TWI869375B - Liquid crystal display device with built-in touch sensing function and manufacturing method thereof - Google Patents

Abstract

The present invention provides a liquid crystal display device with a built-in touch sensing function, which can prevent the generation of static unevenness and maintain a stable touch sensor sensitivity even when exposed to a humid and hot environment. A liquid crystal display device with a built-in touch sensing function is provided. The liquid crystal display device comprises: a liquid crystal layer including liquid crystal molecules; a touch sensor portion; and a first and a second polarizing film respectively arranged on both sides of the liquid crystal layer. The first polarizing film is arranged on the visual side of the liquid crystal layer and is closer to the visual side than the touch sensor portion. The conductive layer is arranged on the visual side closer to the touch sensor portion. The wet-heat conductivity change ratio F _HT represented by the formula (1) under the conductive layer is less than 2. F _HT = ΔC(B)/ΔC(A)…(1) (In formula (1), ΔC(B) is the difference between the touch panel current value after the humidity and heat test and the touch panel base current value, and ΔC(A) is the difference between the touch panel current value before the humidity and heat test and the touch panel base current value)

Description

Liquid crystal display device with built-in touch sensing function and manufacturing method thereof

The present invention relates to a liquid crystal display device with a built-in touch sensing function and a manufacturing method thereof. This application claims priority based on Japanese Patent Application No. 2019-039937 filed on March 5, 2019, and the entire contents of the application are incorporated into this specification by reference.

In recent years, liquid crystal display devices with built-in touch sensing functions have been widely used as image display devices capable of input in various fields such as portable electronic devices and vehicles. In order to prevent the generation of uneven display of liquid crystal caused by static electricity, etc. (hereinafter also referred to as "static unevenness"), such liquid crystal display devices adopt countermeasures such as providing an anti-static layer. For example, when a polarizing film is attached to a liquid crystal unit, static electricity may be generated when the liner is removed from the polarizing film with an adhesive layer. As a prior art document that discloses such a prior art, patent document 1 can be cited. Furthermore, Patent Document 2 discloses a conductive resin composition that can be used for touch panels of various electronic devices, transparent electrodes for liquid crystal driving, etc., and describes that the transparent conductive film contains a conductivity enhancer. [Prior Technical Document] [Patent Document]

Patent document 1: International Publication No. 2017/057097 Patent document 2: Japanese Patent Application Publication No. 2015-117367

[The problem the invention is trying to solve]

The electrostatic capacitance method used in the liquid crystal display device with built-in touch sensing function is an input device that detects the change of electrostatic capacitance generated by the finger touching the touch panel and drives it. Therefore, if the change of electrostatic capacitance to be detected becomes unstable due to the existence of the anti-static layer, it will cause the sensitivity of the touch panel to decrease. Therefore, the anti-static layer used for the built-in touch sensing function is constructed in a way that has conductivity that can simultaneously prevent the generation of static unevenness and the sensitivity of the touch sensor (patent document 1). In terms of the durability or longevity of the device, it is more ideal that the conductivity can also remain stable when used in various environments. However, according to the research results of the inventors, it is known that if the previous antistatic layer is used in a high temperature and high humidity environment, the surface resistance value will decrease, which may cause the touch sensor to malfunction.

The present invention is made in view of the above situation, and its purpose is to provide a liquid crystal display device with a built-in touch sensing function that can prevent the generation of static unevenness and maintain a stable touch sensor sensitivity even when exposed to a humid and hot environment. Another purpose of the present invention is to provide a manufacturing method for a liquid crystal display device with a built-in touch sensing function. [Technical means to solve the problem]

According to the present specification, a liquid crystal display device with a built-in touch sensing function is provided. The liquid crystal display device comprises: a liquid crystal layer including liquid crystal molecules; a touch sensor portion; and a first and a second polarizing film respectively arranged on both sides of the liquid crystal layer. Here, the first polarizing film is arranged on the visual side of the liquid crystal layer and closer to the visual side than the touch sensor portion. Furthermore, in the liquid crystal display device, the conductive layer is arranged on the visual side closer to the touch sensor portion. Furthermore, in some embodiments, the wet-heat conductivity change ratio F _HT represented by the following formula (1) of the conductive layer is less than 2. F _HT = ΔC(B)/ΔC(A)・・・・・(1) (In formula (1), ΔC(B) is the difference between the current flowing in the touch panel and the base current of the touch panel when the conductive layer after the wet heat test at 85°C and 85% relative humidity for 24 hours is placed on the evaluation touch panel, and ΔC(A) is the difference between the current flowing in the touch panel and the base current of the touch panel when the conductive layer before the wet heat test is placed on the evaluation touch panel)

According to the above structure, since the change ratio _FHT of the conductivity of the conductive layer of the liquid crystal display device before and after the wet heat test is less than 2, the change of conductivity is suppressed even when exposed to a wet heat environment. In this way, the generation of static unevenness can be prevented, and the touch sensor sensitivity can be kept stable to prevent the touch sensor from malfunctioning. The liquid crystal display device with a built-in touch sensing function has excellent wet heat durability.

Furthermore, according to the present specification, a liquid crystal display device with a built-in touch sensing function is provided in different aspects. The liquid crystal display device comprises: a liquid crystal layer including liquid crystal molecules; a touch sensor portion; and a first and a second polarizing film respectively arranged on both sides of the liquid crystal layer. Here, the first polarizing film is arranged on the visual side of the liquid crystal layer and closer to the visual side than the touch sensor portion. Furthermore, in the above-mentioned liquid crystal display device, a conductive layer is arranged closer to the visual side than the above-mentioned touch sensor portion. Furthermore, in some aspects, the wet-to-heat surface resistance change ratio S/P of the above-mentioned conductive layer satisfies the condition: 0.05≦S/P≦10. Here, S is the surface resistance value [Ω/□] of the conductive layer after the wet heat test at a temperature of 85°C and a relative humidity of 85% for 24 hours, and P is the surface resistance value [Ω/□] of the conductive layer before the wet heat test. According to the above configuration, the surface resistance change ratio of the conductive layer of the liquid crystal display device before and after the wet heat test is within a specific range, so that it is possible to simultaneously prevent the generation of electrostatic unevenness and stabilize the sensitivity of the touch sensor.

Furthermore, according to the present specification, a liquid crystal display device with a built-in touch sensing function is provided in different aspects. The liquid crystal display device comprises: a liquid crystal layer including liquid crystal molecules; a touch sensor portion; and a first and a second polarizing film respectively arranged on both sides of the liquid crystal layer. Here, the first polarizing film is arranged on the visual side of the liquid crystal layer and closer to the visual side than the touch sensor portion. Furthermore, in the above-mentioned liquid crystal display device, a conductive layer is arranged on the visual side closer to the touch sensor portion. In some aspects, the above-mentioned conductive layer is formed by a conductive composition including a conductive polymer and a high-boiling point compound having a boiling point of 180°C or above. By using a conductive layer formed by a high-boiling point compound having a boiling point of 180°C or more, the conductivity stability after exposure to a humid and hot environment (i.e., wet-heat conductivity stability) is improved, so that even when exposed to a humid and hot environment, the change in conductivity is suppressed. In this way, static unevenness can be prevented and a stable touch sensor sensitivity can be maintained. That is, in the technology disclosed here, the high-boiling point compound is not used to improve conductivity, but is used to improve the sensitivity stability of the touch sensor in a humid and hot environment and improve the wet-heat conductivity stability. This is essentially different from the conductivity improvement using a conductivity enhancer in Patent Document 2. Furthermore, in the technology disclosed herein, the target conductivity can be adjusted by the type and amount of the conductive polymer used.

In some aspects of the technology disclosed herein (including a liquid crystal display device with a built-in touch sensing function, an embedded liquid crystal display device, and a method for manufacturing the same. The same applies below), the wet-heat surface resistance change ratio S/P of the above-mentioned conductive layer satisfies the condition: 0.05≦S/P≦10. Here, S is the surface resistance value [Ω/□] of the conductive layer after a wet-heat test performed at a temperature of 85°C, a relative humidity of 85% and for 24 hours, and P is the surface resistance value [Ω/□] of the conductive layer before the above-mentioned wet-heat test. According to the above structure, the surface resistance change ratio of the conductive layer of the liquid crystal display device based on the wet and hot test is within a specific range. Therefore, even when exposed to a wet and hot environment, the touch sensor can still exhibit good sensitivity stability.

In some preferred embodiments, the content of the high boiling point compound in the conductive composition is 0.1-10 wt%. By setting the content of the high boiling point compound in the conductive composition to a specific range, the effect of the technology disclosed herein can be better exerted.

In some preferred embodiments, the boiling point of the high boiling point compound is 210-290°C. In some other embodiments, the high boiling point compound is preferably a glycol ether solvent. By selecting a suitable high boiling point compound according to the boiling point or chemical structure, even when exposed to a humid and hot environment, a better sensitivity stability of the touch sensor can be achieved.

In some preferred embodiments, the conductive layer includes a thiophene polymer as the conductive polymer. In the structure using the thiophene polymer as the conductive polymer, the effect of improving the stability of the wet-heat conductivity and thus the sensitivity stability of the touch sensor is better exerted.

In some preferred embodiments, the conductive layer contains an adhesive, thereby improving the film forming property of the conductive layer and enabling the conductive layer to be well fixed in the liquid crystal display device.

Furthermore, the liquid crystal display device is preferably an embedded type liquid crystal display device. Unlike the surface embedded type, the conductive layer such as the ITO layer is not provided on the surface of the panel, but is arranged on the visible side of the touch sensor portion. As the conductive layer, a lower resistance layer can be used. Since there is a tendency that the lower the resistance value level, the more difficult it is to eliminate the poor sensitivity of the touch sensor, the importance of resistance stability is higher in the embedded type liquid crystal panel than in the surface embedded type. By configuring a conductive layer with improved moisture-heat conductivity stability in an in-cell liquid crystal display device, the sensitivity of the touch sensor can be stably maintained with good durability for a long period of time, thereby achieving stability of the sensitivity of the touch sensor in the in-cell liquid crystal display device, and further improving the durability and life of the device. The technology disclosed herein is particularly suitable for in-cell liquid crystal panels among various liquid crystal panels.

Furthermore, according to the present specification, a method for manufacturing a liquid crystal display device with a built-in touch sensing function is provided. The liquid crystal display device with a built-in touch sensing function manufactured by the method comprises: a liquid crystal layer including liquid crystal molecules; a touch sensor portion; and a first and a second polarizing film respectively arranged on both sides of the liquid crystal layer. Here, the first polarizing film is arranged on the visual side of the liquid crystal layer and closer to the visual side than the touch sensor portion. The method includes the step of configuring a conductive layer on the visual side closer to the touch sensor portion. Furthermore, the conductive layer is formed by a conductive composition including a conductive polymer and a high-boiling point compound having a boiling point of 180°C or above. According to this method, by forming a conductive layer using a high-boiling-point compound having a boiling point of 180°C or higher, a liquid crystal display device with a built-in touch sensing function can be obtained, which can prevent the generation of static unevenness even when exposed to a humid and hot environment and has excellent touch sensor sensitivity stability.

The following describes the preferred implementation of the present invention. Furthermore, matters not specifically mentioned in this specification and necessary for the implementation of the present invention are understood by the industry based on the teachings of the implementation of the invention recorded in this specification and the technical common sense at the time of application. The present invention can be implemented based on the contents disclosed in this specification and the technical common sense in the area. Furthermore, in the following figures, the components and parts that achieve the same function are described with the same symbols, and repeated descriptions are omitted or simplified. In addition, the implementation forms recorded in the drawings are modeled for the purpose of clearly explaining the present invention, and do not accurately represent the size or scale of the actual products and parts provided.

<Liquid crystal display device with built-in touch sensor function> The liquid crystal display device with built-in touch sensor function disclosed herein has a liquid crystal layer including liquid crystal molecules and a touch sensor portion. In addition, in the above-mentioned liquid crystal display device, a conductive layer is arranged on the visual side closer to the touch sensor portion. Furthermore, the above-mentioned liquid crystal display device can typically be a device in which a polarizing film (first polarizing film) is arranged on the visual side of the liquid crystal layer and closer to the visual side than the touch sensor portion. This type of liquid crystal display device can be a device in which the first and second polarizing films are arranged on both sides of the liquid crystal layer, respectively. At least a portion of the touch sensor portion is disposed between the first polarizing film and the liquid crystal layer. In some embodiments, the touch sensor portion (e.g., the detection electrode and the drive electrode constituting the touch sensor portion) is disposed between the first polarizing film and the liquid crystal layer. In other embodiments, a portion of the touch sensor portion (e.g., the detection electrode) is disposed between the first polarizing film and the liquid crystal layer.

As a liquid crystal display device with a built-in touch sensing function, for example, a device having an embedded liquid crystal panel as shown in Figures 1 to 7 can be cited. In short, the embedded liquid crystal panel has the following structure: in a liquid crystal unit having a liquid crystal layer and two transparent substrates sandwiching the liquid crystal layer, a touch sensing electrode portion related to the touch sensing function is provided in the liquid crystal unit (i.e., on the inner side of the two transparent substrates). The detection electrode and the driving electrode related to the touch sensing function are both arranged in the liquid crystal unit, which is called a fully embedded liquid crystal panel.

1 to 7 are cross-sectional views schematically showing a configuration example of a main part (in-cell liquid crystal panel) of a liquid crystal display device 1 with a built-in touch sensing function. The in-cell liquid crystal panel 101 shown in FIG. 1 includes a liquid crystal cell (in-cell liquid crystal cell) 120 and a first polarizing film 111 disposed on the viewing side of the liquid crystal cell 120.

The liquid crystal cell 120 has a liquid crystal layer 125 including liquid crystal molecules, and a first transparent substrate 141 and a second transparent substrate 142 arranged to sandwich the liquid crystal layer 125. In addition, the liquid crystal cell 120 has a touch sensing electrode portion 130 as a touch sensor portion between the first transparent substrate 141 and the second transparent substrate 142. The touch sensing electrode portion 130 has a detection electrode 131 and a drive electrode 132. Here, the detection electrode is a touch detection (receiving) electrode, which functions as an electrostatic capacitance sensor. The detection electrode is also called a touch sensing electrode.

In the touch sensing electrode portion 130, when the liquid crystal unit 120 is viewed as a plane, the detection electrode 131 and the drive electrode 132 are independently formed in stripes in the X-axis direction and the Y-axis direction of the plane, and the two form a pattern that crosses each other at right angles. The pattern that can be formed in the touch sensing electrode portion 130 is not limited to this, and the detection electrode 131 and the drive electrode 132 can be formed in a manner having various patterns as described below.

In the in-cell liquid crystal panel 101, on the viewing side of the liquid crystal unit 120, specifically, a first adhesive layer 112, a conductive layer 113, and a first polarizing film 111 are sequentially layered from the first transparent substrate 141 toward the viewing side. Without particular limitation, in this configuration example, the first adhesive layer 112, the conductive layer 113, and the first polarizing film 111 are attached to the outer surface of the viewing side of the first transparent substrate 141 in the form of a polarizing film 110 with a conductive layer. The polarizing film 110 with a conductive layer has the following structure: a conductive layer 113 is provided on one surface of a first polarizing film 111, and a first adhesive layer 112 is arranged on one surface of the conductive layer 113 (the surface opposite to the first polarizing film 111). The first adhesive layer 112 is arranged and fixed on the outer surface of the first transparent substrate 141 without interposing the conductive layer. The first polarizing film 111 is arranged on the viewing side of the liquid crystal layer 125 in a manner that the transmission axis (or absorption axis) of the polarizing element thereof is orthogonal. In this structural example, a surface treatment layer 114 is arranged on the back side of the first polarizing film 111.

On the other hand, in the embedded liquid crystal panel 101, a second polarizing film 151 is arranged on the opposite side to the viewing side. The second polarizing film 151 is attached to the outer surface of the second transparent substrate 142 of the liquid crystal unit 120 via the second adhesive layer 152. The second polarizing film 151 is arranged on the back side of the liquid crystal layer 125 in a manner that the transmission axis (or absorption axis) of its polarizing element is orthogonal. Without particular limitation, in this configuration example, the second adhesive layer 152 and the second polarizing film 151 are attached to the outer surface of the second transparent substrate 141 in the form of a polarizing film 150 with a conductive layer. The polarizing film 150 with a conductive layer has a configuration in which the second adhesive layer 152 is arranged on one surface of the second polarizing film 151.

In addition, in the in-cell liquid crystal panel 101, a conductive structure 170 formed of a conductive material is provided on the side surfaces of the conductive layer 113 and the first adhesive layer 112. Thus, the potential can be leaked from the side surfaces of the conductive layer 113 and the first adhesive layer 112 to other parts, and the charging caused by static electricity can be reduced or prevented. The conductive structure 170 can be provided on the entire side surface (end surface) of the conductive layer 113 and the first adhesive layer 112, or it can be provided on a part of the side surface. When the conductive structure 170 is provided in a part, in order to ensure the conduction of the side, the conductive structure 170 can be provided at an area ratio of approximately 1% or more, preferably approximately 3% or more, more preferably approximately 10% or more, and further preferably approximately 50% or more of the total area of the side of the conductive layer 113 and the first adhesive layer 112. Furthermore, in the configuration example shown in FIG. 1 , the conductive structure 171 is also provided on the side of the first polarizing film 111 and the surface treatment layer 114.

The liquid crystal display device 2 with built-in touch sensing function shown in FIG2 is a variation of the structure shown in FIG1, and the layer structure of the visual side of the liquid crystal unit 120 is different from the structure shown in FIG1. Specifically, in the in-cell liquid crystal panel 102, on the visual side of the liquid crystal unit 120, from the first transparent substrate 141 toward the visual side, there are (specifically, laminated) a conductive layer 113, a first adhesive layer 112, and a first polarizing film 111 in sequence, which is different from the structure example of FIG1. Without particular limitation, in this configuration example, the conductive layer 113 is formed on substantially the entire outer surface of the first transparent substrate 141, and the first adhesive layer 112 and the first polarizing film 111 are attached to the conductive layer 113 formed on the outer surface of the visible side of the first transparent substrate 141 in the form of a polarizing film 110 with a conductive layer. The polarizing film 110 with a conductive layer has a configuration in which the first adhesive layer 112 is arranged on one surface of the first polarizing film 111. Furthermore, in FIG. 2, for the convenience of explanation, the surface treatment layer 114 and the conductive structures 170 and 171 on the back side of the first polarizing film 111 are omitted.

The liquid crystal display device 3 with built-in touch sensing function shown in FIG. 3 is also a variation of the structure shown in FIG. 1 , and the layer structure of the visual side of the liquid crystal unit 120 is different from the structure shown in FIG. 1 . Specifically, in the in-cell liquid crystal panel 103, on the visual side of the liquid crystal unit 120, from the first transparent substrate 141 toward the visual side, there are (specifically, laminated) the first adhesive layer 112, the first polarizing film 111, and the conductive layer 113 in sequence, which is different from the structure example of FIG. 1 . Without particular limitation, in this structure example, the first adhesive layer 112, the first polarizing film 111, and the conductive layer 113 are attached to the outer surface of the visual side of the first transparent substrate 141 in the form of a polarizing film 110 with a conductive layer. The polarizing film 110 with a conductive layer has the following structure: a first adhesive layer 112 is disposed on one surface of a first polarizing film 111, and a conductive layer 113 is disposed on the other surface of the first polarizing film 111 (the surface opposite to the surface on which the first adhesive layer 112 is formed). The conductive layer 113 can also be formed on the back surface of the first polarizing film 111 after the first polarizing film 111 is laminated on the viewing side of the liquid crystal unit 120. Furthermore, in FIG. 3, for the convenience of explanation, the surface treatment layer 114 and the conductive structures 170 and 171 on the back surface of the first polarizing film 111 are omitted.

The liquid crystal display device 4 with built-in touch sensing function shown in FIG. 4 is a variation of the structure shown in FIG. 1 , and is different from the structure shown in FIG. 1 in that the touch sensing electrode portion 130 as the touch sensor portion in the in-cell liquid crystal panel 104 is disposed between the liquid crystal layer 125 and the second transparent substrate 142. That is, the touch sensing electrode portion 130 having the detection electrode 131 and the driving electrode 132 is disposed on the backlight side (back side) of the liquid crystal layer 125. The liquid crystal display device 5 with a built-in touch sensing function shown in FIG5 is also a variation of the structure shown in FIG1. In the in-cell liquid crystal panel 105, the touch sensing electrode portion 130 in which the detection electrode and the drive electrode are integrally formed is used, which is different from the structure shown in FIG1. The liquid crystal display device 6 with a built-in touch sensing function shown in FIG6 is a combination of the structures of FIG4 and FIG5. In the in-cell liquid crystal panel 106, the touch sensing electrode portion 130 in which the detection electrode and the drive electrode are integrally formed is used, and the touch sensing electrode portion 130 as the touch sensor portion is arranged on the backlight side (back side) of the liquid crystal layer 125 is different from the structure shown in FIG1.

In addition, the liquid crystal display device 7 with a built-in touch sensing function shown in FIG. 7 is different from the configuration shown in FIG. 1 in that the detection electrode 131 and the drive electrode 132 of the touch sensing electrode portion 130 as the touch sensor portion are separately arranged on both sides of the liquid crystal layer 125 in the in-cell liquid crystal panel 107. Specifically, in the in-cell liquid crystal panel 107, the detection electrode 131 is arranged between the liquid crystal layer 125 and the first transparent substrate 141, and the drive electrode 132 is arranged between the liquid crystal layer 125 and the second transparent substrate 142. The other configurations of the variations shown in FIGS. 2 to 7 are basically the same as those of the in-cell liquid crystal panel shown in FIG. 1, and therefore, repeated descriptions are omitted.

As described above, the embedded liquid crystal panel has a touch sensing electrode portion inside the liquid crystal unit rather than outside the liquid crystal unit. In this configuration, no ITO layer or other electrodes (surface resistance is usually below 1×10 ¹³ Ω/□) are provided on the outer surface of the first transparent substrate of the liquid crystal unit. In this embedded liquid crystal panel, the conductive layer disclosed herein is arranged closer to the viewing side than the first transparent substrate of the liquid crystal unit, thereby, based on the improved wet-heat conductive stability, the touch sensor sensitivity stability can be exerted even when exposed to a wet-heat environment, achieving excellent durability. The effects of the technology disclosed herein (improvement of the stability of the wet-heat conductivity, resulting in improved durability or long-term stable maintenance of the sensitivity of the good touch sensor) can be better exerted in the embedded type.

As another example of the liquid crystal display device with built-in touch sensing function disclosed herein, a device with a semi-embedded liquid crystal panel can be cited. In short, a semi-embedded liquid crystal panel refers to a liquid crystal unit having a liquid crystal layer and two transparent substrates sandwiching the liquid crystal layer, wherein only one of the detection electrode and the driving electrode constituting the touch sensing electrode part related to the touch sensing function is arranged in the liquid crystal unit, and the other of the above electrodes is arranged outside the liquid crystal unit (typically on the outer surface of the transparent substrate).

FIG8 is a cross-sectional view schematically showing an example of the structure of a device having a semi-embedded liquid crystal panel. The liquid crystal display device 8 with a built-in touch sensing function shown in FIG8 is different from the embedded type shown in FIGS. 1 to 7 in the following aspects: In the semi-embedded liquid crystal panel 201, a part of the touch sensing electrode portion 130 as a touch sensor portion is arranged inside the liquid crystal unit 120, and another part of the touch sensing electrode portion 130 is arranged outside the liquid crystal unit 120 (specifically, outside the visual side of the liquid crystal unit 120). Specifically, the detection electrode 131 constituting the touch sensing electrode portion 130 is arranged on the outer surface of the first transparent substrate 141, and the driving electrode 132 constituting the touch sensing electrode portion 130 is arranged inside the liquid crystal unit 120. In this configuration example, the driving electrode 132 is disposed between the liquid crystal layer 125 and the second transparent substrate 142. The semi-cell-type liquid crystal panel 201 has a laminated structure in which the first polarizing film 111, the conductive layer 113, the first adhesive layer 112, the detection electrode 131, the first transparent substrate 141, the liquid crystal layer 125, the driving electrode 132, and the second transparent substrate 142 are disposed in order from the viewing side. In addition, a surface treatment layer 114 is provided on the viewing side of the first polarizing film 111. Furthermore, a second adhesive layer 152 and a second polarizing film 151 are disposed in order on the outer side of the second transparent substrate 142. In the liquid crystal panel 201 , the detection electrode 131 of the touch sensing electrode portion 130 is disposed outside the first transparent substrate 141 and is in contact with the adhesive layer 112 .

As another example of the liquid crystal display device with built-in touch sensing function disclosed herein, a device with a surface-mounted liquid crystal panel can be cited. In short, a surface-mounted liquid crystal panel refers to a liquid crystal unit having a liquid crystal layer and two transparent substrates sandwiching the liquid crystal layer, and a touch sensor function is arranged on the outer surface of the transparent substrate of the liquid crystal unit.

FIG9 is a cross-sectional view schematically showing an example of the structure of a device having a surface-mounted liquid crystal panel. The liquid crystal display device 9 with a built-in touch sensing function shown in FIG9 is different from the embedded type shown in FIGS. 1 to 7 in that the detection electrode 131 and the driving electrode 132 of the touch sensing electrode portion 130 as the touch sensor portion are arranged as electrode patterns outside the liquid crystal unit 120 in the surface-mounted liquid crystal panel 202. In this structure, the touch sensor function is provided outside the liquid crystal unit 120 (specifically, outside the first transparent substrate 141 and the second transparent substrate 142). More specifically, a driving electrode 132 is disposed on the outer surface of the first transparent substrate 141 of the liquid crystal unit 120, and a detection electrode 131 is disposed on the driving electrode 132. The surface-mounted liquid crystal panel 202 has a layered structure in which a first polarizing film 111, a conductive layer 113, a first adhesive layer 112, a detection electrode 131, a driving electrode 132, a first transparent substrate 141, a liquid crystal layer 125, a driving electrode 134, and a second transparent substrate 142 are disposed in order from the viewing side. In addition, a surface treatment layer 114 is provided on the viewing side of the first polarizing film 111. Furthermore, a second adhesive layer 152 and a second polarizing film 151 are sequentially arranged on the outer side of the second transparent substrate 142. In the liquid crystal panel 202, the detection electrode 131 of the touch sensing electrode portion 130 is arranged on the outer side of the first transparent substrate 141 and contacts the first adhesive layer 112. In addition, a driving electrode 134 is arranged in the liquid crystal unit 120. The driving electrode 134 is arranged between the liquid crystal layer 125 and the second transparent substrate 142.

Furthermore, in addition to the above description, the above-mentioned liquid crystal panel or the liquid crystal display device having the liquid crystal panel can also change the arrangement or composition of each component or appropriately add other components according to the use or purpose without damaging the effect of the technology disclosed herein. As an example, a design change such as setting a color filter substrate on the liquid crystal unit (such as the first transparent substrate 141 in Figure 1) can be made.

Furthermore, in the embedded liquid crystal panels shown in Figures 1, 4, and 7, the detection electrode is arranged on the first transparent substrate side (visual side) closer to the driving electrode, but the structure of the embedded liquid crystal panel disclosed here is not limited to this, and the driving electrode may also be arranged on the first transparent substrate side (visual side) closer to the detection electrode.

In addition, in the liquid crystal display device with built-in touch sensing function shown in Figures 4 to 9, the layered structure of the visual side of the liquid crystal unit is configured with a first polarizing film, a conductive layer, and a first adhesive layer in sequence from the visual side, but these structures can also be changed to a layered structure in which a first polarizing film 111, a first adhesive layer 112, and a conductive layer 113 are configured in sequence from the visual side as shown in Figure 2. Alternatively, the layered structure of the viewing side of the liquid crystal unit of the liquid crystal display device with built-in touch sensing function shown in FIGS. 4 to 9 may be changed to a layered structure in which a conductive layer 113, a first polarizing film 111, and a first adhesive layer 112 are sequentially arranged on the viewing side as shown in FIG. 3 .

In addition, in the semi-embedded liquid crystal panel shown in Figure 8, the detection electrode is arranged outside the liquid crystal unit (specifically, outside the first transparent substrate), and the driving electrode is arranged inside the liquid crystal unit (specifically, between the first transparent substrate and the second transparent substrate), but it is not limited to this. The technology disclosed here can also be applied to a semi-embedded liquid crystal panel in which the detection electrode is arranged inside the liquid crystal unit and the driving electrode is arranged outside the liquid crystal unit.

Furthermore, in the above-mentioned configuration example, a polarizing film with an adhesive layer substantially composed of a second adhesive layer and a second polarizing film is used on the back side of the liquid crystal unit, but the technology disclosed herein is not limited thereto, and a polarizing film with a conductive layer as used in the configuration example of FIG. 1 may also be used on the back side of the liquid crystal panel. In this case, the polarizing film with a conductive layer disclosed herein may be arranged on both sides of the liquid crystal unit. The polarizing film arranged on the opposite side of the viewing side may be the same as the polarizing film arranged on the viewing side, or may be different. Alternatively, a known optical film with an adhesive layer may be arranged on the back side of the liquid crystal unit.

As the adhesive layer disposed on the back side of the liquid crystal panel, the adhesive layer disclosed herein or a known or commonly used adhesive layer may be used according to the use or purpose. As the adhesive layer, the same adhesive layer as the adhesive layer disposed on the visual side may be used, or a different adhesive layer may be used. When the adhesive layer disposed on the opposite side of the visual side is formed by a known or commonly used adhesive, the thickness of the adhesive layer is not particularly limited, and is preferably about 1 to 100 μm, preferably about 2 to 50 μm, more preferably about 2 to 40 μm, and further preferably about 5 to 35 μm.

On the viewing side or back side of the liquid crystal unit of the above-mentioned liquid crystal display device with built-in touch sensing function, in addition to the above-mentioned layers (polarizing film, adhesive layer, conductive layer, and any surface treatment layer), an easy-to-bond layer can be set between the polarizing film and the conductive layer, or various easy-to-bond treatments such as corona treatment and plasma treatment can be implemented.

A liquid crystal display device with a touch sensing function is manufactured using a liquid crystal panel (preferably an embedded liquid crystal panel) having the above-described structure. When manufacturing the liquid crystal display device, a backlight or a reflector is used in the lighting system, and various components that can be used in a liquid crystal display device can be used by a known or conventional method. Furthermore, the liquid crystal display device can be a structure in which a touch panel is arranged outside the polarizing film (for example, a structure in which a touch panel is arranged outside a liquid crystal panel of an IPS method, etc.).

Secondly, the components of a liquid crystal display device with a built-in touch sensing function are explained.

<Polarizing film> The polarizing film disclosed herein (including the first and second polarizing films. The same shall apply hereinafter unless otherwise specified) is also referred to as a polarizing plate, and may generally be a film having a polarizing element and a transparent protective film disposed on at least one side (preferably both sides) of the polarizing element. The polarizing element is not particularly limited, and may be, for example, a film in which a dichroic substance such as iodine or a dichroic dye is adsorbed on a hydrophilic polymer film and subjected to uniaxial stretching. Examples of hydrophilic polymer films include: polyvinyl alcohol (PVA) films, partially formalized PVA films, and partially saponified films of ethylene-vinyl acetate copolymers. As polarizing elements, polyene-based alignment films such as dehydrated PVA films or dehydrogenated polyvinyl chloride films may also be used. Among them, PVA films and polarizing elements containing dichroic substances such as iodine are preferred.

There is no particular restriction on the thickness of the polarizing element, but it is generally less than 80 μm. From the perspective of minimizing the thickness, a polarizing element with a thickness of less than 10 μm (preferably about 1 to 7 μm) can be preferably used. A polarizing element with a smaller thickness has less uneven thickness and excellent visibility, and also has less dimensional changes, so it is also excellent in durability. Using a polarizing element with a smaller thickness also helps to minimize the thickness of the polarizing film.

As the material constituting the transparent protective film, for example, a thermoplastic resin having excellent transparency, mechanical strength, thermal stability, moisture blocking property, isotropy, etc. is preferably used. Specific examples of such thermoplastic resins include cellulose resins such as triacetyl cellulose (TAC), polyester resins, polyether resins, polyester resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth)acrylic resins, cycloolefin resins (typically norbutyl resins), polyacrylate resins, polystyrene resins, PVA resins, and mixtures of two or more of these resins. In a preferred embodiment, a transparent protective film containing a thermoplastic resin such as TAC may be arranged on one side of the polarizing element, and a transparent protective film containing a cycloolefin resin (typically a norbutyl resin) or a (meth) acrylic resin may be arranged on the other side. In other preferred embodiments, a transparent protective film containing a thermoplastic resin such as TAC may be arranged on one side of the polarizing element, and a thermosetting resin or ultraviolet curing resin such as (meth) acrylic, urethane, acrylic urethane, epoxy, silicone, etc. may be used as a transparent protective film on the other side. Such transparent protective films may be laminated on the polarizing element via adhesives such as PVA. The transparent protective film may contain one or more of any appropriate additives according to the purpose.

The adhesive used to bond the polarizing element to the transparent protective film is not particularly limited as long as it is optically transparent, and various forms of adhesives such as water-based, solvent-based, hot melt-based, free radical curing, and cationic curing can be used. Among them, water-based adhesives or free radical curing adhesives are preferred.

Furthermore, a surface treatment layer may be provided on the back of the polarizing film. The surface treatment layer may be provided on the polarizing film in addition to the transparent protective film mentioned above, or may be provided on the polarizing film as a separate object from the transparent protective film.

As a preferred example of the surface treatment layer, a hard coating layer can be cited. As the material for forming the hard coating layer, for example, a thermoplastic resin or a material that is hardened by heat or radiation can be used. As the material used, radiation-hardening resins such as thermosetting resins, ultraviolet-hardening resins, and electron beam-hardening resins can be cited. Among them, ultraviolet-hardening resins are preferred. Ultraviolet-hardening resins can efficiently form a hardened resin layer by hardening treatment due to ultraviolet irradiation, so they are excellent in processability. As the curing resin, one or more of polyester, acrylic, urethane, amide, silicone, epoxy, melamine, etc. can be used, and these can be in the form of monomers, oligomers, polymers, etc. Since no heat is required (which may cause damage to the substrate) and the processing speed is excellent, radiation curing resins (typically ultraviolet curing resins) are particularly preferred.

As other examples of surface treatment layers, an anti-glare treatment layer or an anti-reflection layer for improving visibility can be listed. An anti-glare treatment layer or an anti-reflection layer can be provided on the above-mentioned hard coating layer. The constituent material of the anti-glare treatment layer is not particularly limited, for example, radiation-hardening resins, thermosetting resins, thermoplastic resins, etc. can be used. As an anti-reflection layer, titanium oxide, zirconium oxide, silicon oxide, magnesium fluoride, etc. can be used. The anti-reflection layer can be a multi-layer structure including a plurality of layers. As other examples of surface treatment layers, anti-sticking layers, etc. can be listed.

When the technology disclosed herein is implemented in a state with a surface treatment layer, the surface treatment layer may contain a conductive agent to impart conductivity. As the conductive agent, the following conductive agents or conductive components may be used without particular limitation. Therefore, the surface treatment layer may be the conductive layer disclosed herein. Furthermore, when the surface treatment layer and the conductive layer are provided on the back of the polarizing film, their configuration is not particularly limited, and the surface treatment layer may be provided between the polarizing film and the conductive layer, or the conductive layer may be provided between the polarizing film and the surface treatment layer.

The thickness of the polarizing film disclosed herein (the total thickness of such layers when including multiple layers) is not particularly limited, for example, it is approximately 1 μm or more, usually approximately 10 μm or more, and preferably approximately 20 μm or more. For example, when a transparent protective film is provided, from the perspective of protection, the thickness of the polarizing film is preferably approximately 30 μm or more, more preferably approximately 50 μm or more, and further preferably approximately 70 μm or more. There is no particular restriction on the upper limit of the polarizing film, for example, it is approximately 1 mm or less, usually approximately 500 μm or less, and preferably approximately 300 μm or less. From the perspective of optical properties or minimization of thickness, the above thickness is preferably approximately 150 μm or less, more preferably approximately 120 μm or less, and further preferably approximately 100 μm or less.

<Conductive layer> The conductive layer disclosed here is a layer that is arranged on the visual side of the touch sensor portion to improve the conductivity of the visual side of the liquid crystal display device and prevent the generation of static unevenness. The conductive layer can be formed by a conductive composition including various conductive agents such as organic or inorganic conductive substances. In the state where the adhesive layer is arranged on the conductive layer, it can function as a thickening layer to improve the adhesion between the adhesive layer and the polarizing film.

Examples of organic conductive substances that may be included in the conductive composition (and therefore in the conductive layer as well, unless otherwise specified) include: quaternary ammonium salts, pyridinium salts, cationic conductive agents having cationic functional groups such as primary amine groups, secondary amine groups, and tertiary amine groups; anionic conductive agents having anionic functional groups such as sulfonates or sulfates, phosphonates, and phosphates; Amphoteric ionic conductors such as alkyl betaine and its derivatives, imidazoline and its derivatives, alanine and its derivatives; non-ionic conductors such as amino alcohol and its derivatives, glycerol and its derivatives, polyethylene glycol and its derivatives; ionic conductive polymers obtained by polymerizing or copolymerizing the above monomers having cationic, anionic, or amphoteric ionic conductive groups (e.g., quaternary ammonium salt groups). Such conductive agents may be used alone or in combination of two or more.

Examples of inorganic conductive materials that may be included in the conductive layer include tin oxide, antimony oxide, indium oxide, cadmium oxide, titanium oxide, zinc oxide, indium, tin, antimony, gold, silver, copper, aluminum, nickel, chromium, titanium, iron, cobalt, copper iodide, ITO (indium oxide/tin oxide), ATO (antimony oxide/tin oxide), etc. Such inorganic conductive materials may be used alone or in combination of two or more.

(Conductive polymer) In some preferred embodiments, a conductive polymer is used as a conductive agent. By using a conductive polymer, a conductive layer having excellent optical properties, appearance, and antistatic effect can be obtained. In addition, the effect of improving the wet-heat conductive stability of the technology disclosed herein tends to be better exerted in a conductive layer containing a conductive polymer. Examples of conductive polymers include polymers such as polyaniline, polythiophene, polypyrrole, polyquinoline, polyethyleneimine, and polyallylamine. Such conductive polymers can be used alone or in combination of two or more.

As preferred examples of conductive polymers, polythiophene (thiophene polymers) and polyaniline (aniline polymers) can be cited. In addition, in this specification, polythiophene refers to polymers of unsubstituted or substituted thiophene. As a preferred example of substituted thiophene polymers in the technology disclosed herein, poly(3,4-ethylenedioxythiophene) can be cited.

As the above-mentioned conductive polymer, organic solvent-soluble or water-soluble and water-dispersible ones can be used without particular limitation. In some preferred embodiments, the conductive polymer is used to form a conductive layer in the form of an aqueous solution or an aqueous dispersion. In this embodiment, since the coating liquid containing the conductive composition can be set in the form of an aqueous liquid (an aqueous solution or an aqueous dispersion that can contain water and other solvents), the risk of polarizing film deterioration caused by organic solvents can be reduced. Conductive polymers such as polyaniline and polythiophene are easily in the form of aqueous solutions or aqueous dispersions, and are therefore preferably used. Among them, polythiophene is more preferred. In some preferred embodiments, a polythiophene aqueous solution is used to prepare the conductive composition. Furthermore, the aqueous solution or aqueous dispersion may contain an aqueous solvent in addition to water. For example, one or more alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, t-butanol, n-pentanol, isopentanol, sec-pentanol, t-pentanol, 1-ethyl-1-propanol, 2-methyl-1-butanol, n-hexanol, and cyclohexanol can be used in the form of a mixed solvent (aqueous solvent) with water.

The aqueous solution or aqueous dispersion of the conductive polymer can be prepared, for example, by dissolving or dispersing a conductive polymer having a hydrophilic functional group (which can be synthesized by copolymerizing a monomer having a hydrophilic functional group in the molecule) in water. Examples of the hydrophilic functional group include sulfonic group, amine group, amide group, imine group, hydroxyl group, hydroxyl group, hydrazine group, carboxyl group, quaternary ammonium group, sulfate group (-O-SO ₃ H), phosphate group (e.g., -O-PO(OH) ₂ ), etc. The hydrophilic functional group can form a salt.

In some preferred embodiments, a polyanion is used as a dopant when preparing a conductive composition (specifically, a dopant of a thiophene-based polymer). In this embodiment, the conductive layer may contain a polyanion. As the polyanion, one or more polycarboxylic acids such as polyacrylic acid or polysulfonic acids such as polystyrene sulfonate (PSS) may be used. In a particularly preferred embodiment, a polythiophene aqueous solution containing PSS is used (which may be in the form of adding PSS to polythiophene as a dopant). The aqueous solution may contain polythiophene:PSS in a weight ratio of 1:1 to 1:10. The total content of polythiophene and PSS in the above aqueous solution may be, for example, about 1 to 5% by weight.

Examples of commercially available polythiophene aqueous solutions include the "Denatron" series manufactured by Nagase Chemicals and the "Clevios" series manufactured by Heraeus. Examples of commercially available polyaniline sulfonic acid aqueous solutions include the "aqua-PASS" series manufactured by Mitsubishi Rayo Corporation.

From the viewpoint of antistatic, the content of the conductive agent (preferably a conductive polymer) in the conductive composition is preferably about 0.005 wt% or more, preferably about 0.01 wt% or more. The upper limit of the content of the conductive agent (preferably a conductive polymer) in the conductive composition is, for example, preferably about 5 wt% or less, preferably about 3 wt% or less, more preferably about 1 wt% or less, and further preferably about 0.7 wt% or less. In the conductive layer obtained using the conductive composition, the content of the conductive agent (preferably a conductive polymer) is preferably about 1 wt% or more, preferably about 3 wt% or more, more preferably about 5 wt% or more, further preferably about 7 wt% or more, and particularly preferably about 10 wt% or more from the viewpoint of antistatic. The upper limit of the content of the conductive agent (preferably a conductive polymer) in the conductive layer is preferably approximately 90% by weight or less.

In the case of using a conductive layer containing a conductive polymer, the conductive layer may also contain a conductive component other than the conductive polymer. Examples of such conductive components include: those exemplified as organic or inorganic conductive substances (other than the conductive polymer), or conductive components contained in the adhesive layer described later. These may be used alone or in combination of two or more. In the technology disclosed herein, the content of conductive components other than the conductive polymer in the conductive layer may be set within a range that does not impair the effect of the invention. The content is generally about 5% by weight or less in the conductive layer, preferably about 3% by weight or less (for example, about 1% by weight or less, typically about 0.3% by weight or less). The technology disclosed herein may be preferably implemented in a case where the conductive layer does not substantially contain conductive components other than the conductive polymer.

(High boiling point compound) The conductive layer disclosed herein is typically formed of a conductive composition containing a high boiling point compound having a boiling point of 180°C or more. The conductive layer formed using the high boiling point compound exhibits improved wet-heat conductive stability. Even when a liquid crystal display device having the conductive layer is exposed to a wet-heat environment, it can prevent the generation of static unevenness and maintain a stable touch sensor sensitivity. The high boiling point compound can be used alone or in combination of two or more. The high boiling point compound may be one that does not remain by volatilization when forming the conductive layer, and the conductive layer formed may better satisfy the wet-heat surface resistance change ratio or wet-heat surface resistance reduction rate, and may better satisfy the wet-heat conductivity change ratio F _HT . The above-mentioned high boiling point compound is a compound with a boiling point of 180° C. or more, and is solid or liquid at room temperature (23° C.). The high boiling point compound that is solid at room temperature is preferably one that is easily soluble in a solvent (such as water) of the conductive composition described later. The solubility of such a high boiling point compound in 100 mL of a solvent (such as water) may be approximately 1 g or more at room temperature (typically approximately 3 g or more, for example approximately 10 g or more, and further approximately 20 g or more). Furthermore, from the viewpoint of the conductive layer formation, the high boiling point compound is preferably a compound that is liquid at a temperature of 20 to 50°C (thus the melting point is below 20°C). Such a compound is also called a high boiling point solvent. Furthermore, the so-called solvent mentioned here refers to the liquid medium contained in the conductive composition. For the sake of convenience, it is called a solvent, but it is a concept that includes solvents and dispersion media.

The reason why the wet thermal conductivity stability is improved by using a high boiling point compound is considered to be as follows. For example, when a low boiling point solvent such as water (a solvent with a boiling point of less than 180°C) is used as a solvent for a conductive composition, the thickness of the conductive layer is relatively small (for example, the thickness is less than 1 μm), so the solvent in the composition evaporates and dries quickly. At this time, the configuration (which may be the orientation) of the conductive agent (preferably a conductive polymer) contained in the composition in the conductive layer will also be affected by the drying process. The high boiling point compound appropriately controls the volatility of the solvent in the drying process when forming the conductive layer, and as a result, the configuration of the conductive agent in the conductive layer is kept good. In addition, according to the research results of the inventors, it is believed that the high-boiling-point compound with a boiling point above a specific value also makes the configuration of the conductive agent in the conductive layer less likely to change due to external factors such as environmental changes during the drying process, thereby maintaining stability. The inventors used TOF/MS (time-of-flight mass spectrometer) to heat a mixed solvent of water and diethylene glycol (boiling point: about 244°C) and a mixed solvent of water and N-methylpyrrolidone (boiling point: about 204°C) at 50°C, and measured the amount of volatile components at this time over time. It was confirmed that when a mixed solvent of a specific high-boiling-point compound (specifically, a boiling point of 180°C or above) was used, if the initial stage of the drying process was passed, the high-boiling-point compound slowly evaporated during the main period of the process. It is believed that the above volatility behavior based on the use of high boiling point compounds helps the conductive agent maintain a stable configuration, and even when exposed to a humid and hot environment, it has stable conductivity. It is believed that this effect is particularly meaningful in the case where a thiophene polymer or an aniline polymer that conducts electrons through the action of π-π stacking is used as a conductive agent (preferably a thiophene polymer, such as a thiophene polymer and a dopant such as PSS). Furthermore, the technology disclosed here is not limited to the above discussion.

The high boiling point compound contained in the conductive composition disclosed herein is also called a conductivity stabilizer due to its wet heat conductivity stabilizing effect. The above conductivity stabilizer can be defined as an agent that suppresses the change of the conductivity (which can be evaluated based on the surface resistance value, etc.) of the conductive layer when exposed to a wet heat environment (e.g., temperature above 50°C, relative humidity above 80%, typically temperature 85°C, 85%RH) for a specific time (e.g., 24 hours) compared to the case where the agent is not used, that is, an agent that helps stabilize the conductivity of the conductive layer in the above environment.

In some aspects, the boiling point of the high boiling point compound contained in the conductive composition is preferably about 200°C or higher, more preferably about 210°C or higher, further preferably about 220°C or higher, and particularly preferably about 230°C or higher (e.g., about 240°C or higher) from the viewpoint of wet heat conductivity stability. The upper limit of the boiling point of the high boiling point compound is appropriately set in consideration of the film forming properties of the conductive layer, drying efficiency, etc., and is not limited to a specific range. The boiling point of the high-boiling-point compound is usually about 400°C or less, preferably about 320°C or less. From the viewpoint of adhesion to the layer adjacent to the conductive layer (for example, an adhesive layer or the first polarizing film, the first transparent substrate), it is preferably about 300°C or less (for example, about 290°C or less), more preferably about 280°C or less, further preferably about 260°C or less, and particularly preferably about 250°C or less.

As the high boiling point compound, for example, lactam compounds such as N-methylpyrrolidone (which may be a lactam solvent) can be used without particular limitation; glycol compounds such as ethylene glycol, propylene glycol, trimethylene glycol, butanediols (1,3-butanediol, 1,4-butanediol, etc.), pentanediols (1,5-pentanediol, etc.), hexanediols (1,6-hexanediol, etc.), neopentyl glycol, o-catecholate (which may be a glycol solvent); glycol ether compounds such as diethylene glycol, triethylene glycol, tripropylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, etc. can be used. Compounds (which may be glycol ether solvents); thiodiol compounds such as β-thiodiethanol (which may be thiodiol solvents); glycerol; sugar alcohol compounds such as mannitol, sorbitol, and xylitol; aromatic alcohol compounds such as 2-phenoxyethanol; amide compounds such as N-methylformamide, acetamide, N-ethylacetamide, and benzamide (which may be amide solvents); amine compounds such as pyrazole (typically cyclic amines); sulfoxide compounds such as dimethyl sulfoxide (which may be sulfoxide solvents); and the like having a boiling point of 180° C. or higher. These compounds may be used alone or in combination of two or more. Among them, preferred are glycol compounds, glycol ether compounds, and glycerin having a boiling point of 180° C. or higher, and more preferred are glycol ether compounds (typically diethylene glycol and triethylene glycol) having a boiling point of 180° C. or higher.

Although not particularly limited, as the high boiling point compound, a compound having a hydroxyl group is preferably used. The high boiling point compound having a hydroxyl group is easily soluble in a solvent (typically an aqueous solvent), and it is believed that, for example, when added to an aqueous solvent, a good volatility behavior leading to improved wet thermal conductivity stability can be obtained. In some preferred embodiments, the number of hydroxyl groups contained in the high boiling point compound is 2 or more, for example, 3 or more. In addition, for example, a compound containing an ether structure can be preferably used.

The content of the high boiling point compound in the conductive composition disclosed herein is appropriately set in order to achieve the target wet heat conductivity stability and the wet heat durability of the liquid crystal display device, and is not limited to a specific range. From the perspective of obtaining the effect of improving the wet heat conductivity stability, the content of the high boiling point compound in the conductive composition is preferably set to about 0.1 weight % or more, preferably about 0.5 weight % or more, more preferably about 1 weight % or more, and further preferably about 2 weight % or more, and can also be about 5 weight % or more (for example, about 8 weight % or more). In addition, the upper limit of the content of the high-boiling-point compound in the conductive composition can be set to, for example, approximately 50 wt% or less, preferably approximately 30 wt% or less (e.g., approximately 25 wt% or less), and from the viewpoint of adhesion to the layer adjacent to the conductive layer (e.g., the adhesive layer or the first polarizing film, the first transparent substrate), preferably approximately 15 wt% or less, more preferably approximately 10 wt% or less, further preferably approximately 7 wt% or less, and particularly preferably approximately 5 wt% or less (typically 4 wt% or less).

The conductive composition used to form the conductive layer typically includes a solvent or a dispersion medium (hereinafter collectively referred to as "solvent" for convenience). The solvent is not particularly limited, and it is preferred to use a solvent that can stably dissolve or disperse the conductive layer forming components. The solvent can be an organic solvent, water, or a mixed solvent thereof. As the organic solvent, for example, one or more selected from esters such as ethyl acetate; ketones such as methyl ethyl ketone, acetone, and cyclohexanone; cyclic ethers such as tetrahydrofuran (THF) and dioxane; aliphatic or alicyclic hydrocarbons such as n-hexane and cyclohexane; aromatic hydrocarbons such as toluene and xylene; aliphatic or alicyclic alcohols such as methanol, ethanol, n-propanol, isopropanol, and cyclohexanol; glycol ethers such as alkylene glycol monoalkyl ethers (e.g., ethylene glycol monomethyl ether, ethylene glycol monoethyl ether), etc. can be used. In addition, the solvent is liquid at room temperature and has a boiling point of less than 180°C.

In some preferred embodiments, the solvent is an aqueous solvent. Here, the aqueous solvent refers to water or a mixed solvent with water as the main component (for example, a mixed solvent of water and lower alcohols such as methanol and ethanol). In the technology disclosed herein, an aqueous solvent is preferably used. This is, for example, preferred from the perspective of preventing the polarizing film from deteriorating in a state where the conductive layer and the first polarizing film are arranged adjacent to each other. The ratio of water in the aqueous solvent should preferably be approximately 30% by weight or more, preferably approximately 50% by weight or more (typically more than 50% by weight), may be approximately 70% by weight or more, and may also be approximately 80% by weight or more (for example, approximately 90 to 100% by weight).

(Adhesive) In some aspects, the conductive layer contains an adhesive. By making the conductive layer contain an adhesive, the film formability of the conductive layer is improved, and the adhesion with the layer adjacent to the conductive layer (such as the adhesive layer or the first polarizing film, the first transparent substrate) is improved. As the adhesive, there is no particular limitation, and one or more of oxazoline-containing polymers, urethane polymers, acrylic polymers, polyester polymers, polyether polymers, cellulose polymers, vinyl alcohol polymers, epoxy-containing polymers, vinyl pyrrolidone polymers, styrene polymers, polyethylene glycol, pentaerythritol, etc. can be used. As a preferred example, there can be listed: oxazoline-containing polymers, urethane polymers (typically polyurethane).

In some preferred embodiments, a polymer containing an oxazoline group is used as an adhesive. By using a polymer containing an oxazoline group, it is easy to obtain wettability on the surface of the polarizing film and tend to improve the grip of the adhesive layer. The oxazoline-containing polymer can be used alone or in combination of two or more. Preferably, it is a polymer containing an oxazoline group that can be dissolved or dispersed in water. The oxazoline group can be any of 2-oxazoline group, 3-oxazoline group, and 4-oxazoline group, for example, a 2-oxazoline group can be preferably used. As a polymer containing an oxazoline group, for example, a main chain containing a (meth) acrylic skeleton or a styrene skeleton and a side chain of the main chain having an oxazoline group can be used. Some preferred oxazoline group-containing polymers may be oxazoline group-containing (meth)acrylic acid-based polymers having a main chain including a (meth)acrylic acid backbone and having oxazoline groups on the side chains of the main chain.

The molecular weight of the oxazoline group-containing polymer can be appropriately set according to the purpose or required characteristics. The upper limit of the molecular weight of the oxazoline group-containing polymer is preferably about 100×10 ⁴ or less, preferably about 50×10 ⁴ or less, more preferably about 10×10 ⁴ or less, and further preferably about 5×10 ⁴ or less from the viewpoint of coating properties. The above molecular weight is the number average molecular weight (Mn) converted to standard polystyrene obtained by GPC (gel permeation chromatography).

In some aspects, a urethane polymer is used as an adhesive. By using a urethane polymer, there is a tendency to improve the adhesion with the layer adjacent to the conductive layer (for example, an adhesive layer or a first polarizing film, a first transparent substrate). Examples of the urethane polymer include: polyurethanes such as ether polyurethanes, ester polyurethanes, and carbonate polyurethanes; (meth)acrylic urethanes, or acrylic-urethane copolymers obtained by copolymerizing (meth)acrylic alkyl esters; and the like. One type of urethane polymer may be used alone, or two or more types may be used in combination. In some aspects, it is preferred to use a polymer containing an oxazoline group and a urethane polymer as an adhesive.

The content of the adhesive in the conductive layer is not particularly limited, and is preferably about 3% by weight or more, for example. From the perspective of adhesion, the content of the adhesive is preferably about 10% by weight or more, more preferably about 30% by weight or more, and further preferably about 50% by weight or more, particularly preferably about 60% by weight or more, and may be about 70% by weight or more (for example, about 80% by weight or more). Considering the effects of other components such as conductive polymers, the upper limit of the content of the adhesive is usually about 99% by weight or less, preferably about 95% by weight or less, and may be about 90% by weight or less (for example, about 80% by weight or less).

Additives may be added to the conductive layer as needed. Examples of additives include leveling agents, defoaming agents, thickeners, antioxidants, etc. The proportion of these additives in the conductive layer is usually about 50% by weight or less, preferably about 30% by weight or less (e.g., about 10% by weight or less), and may also be about 3% by weight or less (e.g., less than 1% by weight).

(Method for forming a conductive layer) The conductive layer can be preferably formed by a method including applying a liquid conductive composition obtained by dispersing or dissolving the conductive agent or high boiling point compound and an additive as needed in a suitable solvent to a polarizing film. For example, the following method can be preferably adopted: applying the conductive composition on one side of the polarizing film, drying it, and performing a curing treatment (heat treatment, ultraviolet treatment, etc.) as needed. Alternatively, in the state where the conductive layer is formed on the outer surface of the first transparent substrate, the conductive composition is applied to the surface of the first transparent substrate by a known method such as roll coating, rod coating, dip coating, spin coating, casting, die coating, gravure coating, spray coating, spray printing, screen printing, inkjet printing, offset printing, etc., and dried and cured as needed to form the conductive layer. The solid content concentration (NV) of the conductive composition can be set to 5% by weight or less (typically 0.05 to 5% by weight), and is usually preferably set to 3% by weight or less (typically 0.10 to 3% by weight). When forming a thinner conductive layer, it is preferred to set the NV of the conductive composition to, for example, 0.05-0.50 wt % (e.g., 0.10-0.30 wt %). By using a conductive composition with a low NV, a more uniform conductive layer can be formed.

(Surface resistance) The surface resistance of the conductive layer is preferably approximately 1×10 ¹² Ω/□ or less from the viewpoint of anti-static, etc. If a conductive layer whose surface resistance is limited to a specific value or less is applied to a liquid crystal panel (e.g., an embedded liquid crystal panel), static unevenness is prevented from occurring based on the conductivity of the conductive layer. Furthermore, from the viewpoint of the sensitivity of the touch sensor, the lower limit of the surface resistance is preferably set to approximately 1×10 ⁶ Ω/□ or more. The range of the surface resistance of the conductive layer may vary depending on whether the first adhesive layer is conductive, the type of liquid crystal unit, the use in portable electronic equipment or in-vehicle use, etc. For example, when applied to an embedded liquid crystal cell for portable electronic devices, the surface resistance value is preferably approximately 1×10 ⁸ Ω/□ to 1×10 ¹⁰ Ω/□, and from the perspective of antistatic, it is more preferably approximately 1×10 ⁸ Ω/□ to 1×10 ⁹ Ω/□. When applied to an embedded liquid crystal cell for vehicle use, it is preferably approximately 1×10 ⁶ Ω/□ to 1×10 ⁹ Ω/□, and from the perspective of antistatic, it is more preferably approximately 1×10 ⁷ Ω/□ to 5×10 ⁸ Ω/□. Furthermore, when applied to a surface-embedded liquid crystal cell, the surface resistance value is preferably approximately 1×10 ¹⁰ Ω/□ to 1×10 ¹² Ω/□. When applied to a semi-intercalated liquid crystal cell, the surface resistance is preferably approximately 1×10 ⁹ Ω/□ to 1×10 ¹² Ω/□. The surface resistance of the conductive layer is measured by the method described in the examples below (initial surface resistance).

(Wet-heat surface resistance change ratio) The conductive layer disclosed herein may be characterized in certain aspects in that the ratio of the surface resistance value S[Ω/□] of the conductive layer after a wet-heat test at a temperature of 85°C, a relative humidity of 85% and for 24 hours to the surface resistance value P[Ω/□] of the conductive layer before the wet-heat test (wet-heat surface resistance change ratio S/P) satisfies the condition: 0.05≦S/P≦10. The conductive layer satisfying the wet-heat surface resistance change ratio S/P exhibits improved wet-heat conductivity stability and can exhibit good touch sensor sensitivity stability even when exposed to a wet-heat environment. The above-mentioned wet-to-heat surface resistance change ratio S/P is preferably approximately greater than 0.1, more preferably approximately greater than 0.5, and further preferably approximately greater than 0.8 (for example, approximately greater than 1). In addition, the above-mentioned S/P is preferably approximately less than 3, more preferably approximately less than 1.5, further preferably approximately less than 1.2, and particularly preferably less than 1.1. The wet-to-heat surface resistance change ratio S/P is measured by the method described in the embodiments described later. Furthermore, the liquid crystal display device with a built-in touch sensing function disclosed in this specification includes a state in which the above-mentioned wet-to-heat surface resistance change ratio S/P is not limited. In this state, the liquid crystal display device with a built-in touch sensing function is not limited to those having the above-mentioned characteristics.

(Wet heat surface resistance reduction rate) In some aspects, the conductive layer may have a wet heat surface resistance reduction rate suppressed to below a specific value. Specifically, the wet heat surface resistance reduction rate of the conductive layer based on the formula: (1-S/P)×100 may be below 95%. Here, S is the surface resistance value [Ω/□] of the conductive layer after a wet heat test performed at a temperature of 85°C, a relative humidity of 85% and for 24 hours, and P is the surface resistance value P [Ω/□] of the conductive layer before the above wet heat test. S and P are measured by the method described in the following embodiment. The conductive layer that satisfies the above-mentioned wet heat surface resistance reduction rate can be one that effectively suppresses the reduction of the surface resistance value when exposed to a wet heat environment. The above-mentioned wet heat surface resistance reduction rate is preferably approximately 90% or less, more preferably approximately 50% or less, further preferably approximately 20% or less, and particularly preferably approximately 0% or less. The technology disclosed herein can be related to suppressing the reduction of the surface resistance when exposed to a wet heat environment. Therefore, there is no particular limitation on the increase of the surface resistance value after the wet heat test. For example, the wet heat surface resistance increase rate calculated based on the formula: (S/P-1)×100 is preferably approximately 200% or less, and can be less than 150%, or less than 130% (for example, less than 120%). The meanings of S and P in the above formula are the same as those of S and P in the above wet heat surface resistance reduction rate.

(Hygro-thermal factor F _HT ) The conductive layer disclosed herein may be characterized in some aspects by a hygro-thermal factor F _HT (Hygro-thermal factor) represented by the following formula (1) being 2 or less. F _HT = ΔC(B)/ΔC(A)・・・・・(1) In the above formula (1), ΔC(B) is the difference between the current value flowing in the touch panel and the base current value of the touch panel when the conductive layer after the humidity and heat test is performed at a temperature of 85°C and a relative humidity of 85% for 24 hours is arranged on the evaluation touch panel, and ΔC(A) is the difference between the current value flowing in the touch panel and the base current value of the touch panel when the conductive layer before the humidity and heat test is arranged on the evaluation touch panel. The conductive layer satisfying this characteristic can maintain stable conductivity even when exposed to a hot and humid environment, preventing the generation of static unevenness, and maintaining stable touch sensor sensitivity to prevent malfunction of the touch sensor. From this point of view, the above F _HT is preferably approximately 1.7 or less, more preferably approximately 1.5 or less, further preferably approximately 1.3 or less, and even more preferably approximately 1.1 or less (e.g., 1.0 or less). The technology disclosed herein can be related to suppressing the decrease in surface resistance (increase in conductivity) when exposed to a wet and hot environment. Therefore, the decrease in conductivity after the wet and hot test (i.e., the decrease in F _HT ) is not particularly limited. The above F _HT is usually approximately 0.1 or more (e.g., approximately 0.3 or more), preferably approximately 0.5 or more, preferably approximately 0.6 or more, more preferably approximately 0.7 or more, further preferably approximately 0.8 or more, and particularly preferably approximately 0.9 or more (typically 0.95 or more, for example, 0.99 or more). The above F _HT is measured by the method described in the embodiments described below. Furthermore, the liquid crystal display device with a built-in touch sensing function disclosed in this specification includes a state where the above-mentioned wet-thermal conductivity change ratio F _HT is not limited. In this state, the liquid crystal display device with a built-in touch sensing function is not limited to those having the above-mentioned characteristics.

(Thickness of the conductive layer) The thickness of the conductive layer in the technology disclosed herein can be appropriately set according to the required characteristics such as antistatic properties and adhesion. The thickness of the conductive layer is usually about 10 nm or more, and preferably more than 10 nm. From the perspective of improving antistatic properties or obtaining uniform thickness, the thickness of the conductive layer is preferably 12 nm or more, more preferably 14 nm or more, further preferably 15 nm or more, and particularly preferably 20 nm or more (typically 25 nm or more, for example 30 nm or more). In addition, the thickness of the conductive layer is preferably set to about 500 nm or less. By suppressing the thickness of the conductive layer to about 500 nm or less, it is easy to obtain good optical properties (total light transmittance, etc.). From this viewpoint, the thickness of the conductive layer is preferably less than about 100 nm, more preferably less than about 70 nm. In a structure having a conductive layer with a smaller thickness, the effect of using a high boiling point compound disclosed herein (improvement of wet thermal conductivity stability) can be better exerted.

<Adhesive layer> The liquid crystal display device with built-in touch sensing function disclosed herein may be provided with an adhesive layer (including the first and second adhesive layers. The same shall apply hereinafter unless otherwise specified) for the purpose of fixing the first polarizing film to the liquid crystal unit. The adhesive constituting the adhesive layer may be, for example, an adhesive layer comprising one or more adhesives selected from acrylic, rubber, urethane, silicone, vinyl alkyl ether, vinyl pyrrolidone, acrylamide, cellulose, etc. Therefore, the polymer constituting the adhesive layer may be an acrylic polymer, a rubber polymer, a urethane polymer, a silicone polymer, a vinyl alkyl ether polymer, a vinyl pyrrolidone polymer, an acrylamide polymer, a cellulose polymer, etc. Among them, acrylic adhesives are preferred from the viewpoints of transparency, appropriate wettability, adhesion properties such as cohesion or adhesion, weather resistance, heat resistance, etc. Hereinafter, the above-mentioned adhesive layer is a structure of an acrylic adhesive layer as a main example to explain the technology disclosed herein in more detail, and it is not intended to limit the above-mentioned adhesive layer to those containing acrylic adhesives.

(Acrylic adhesive) The so-called acrylic adhesive used in some preferred embodiments refers to an adhesive having an acrylic polymer as the base polymer (the main component among the polymer components contained in the adhesive, i.e., the component that accounts for more than 50% by weight). In addition, the so-called "acrylic polymer" refers to a polymer having a monomer having at least one (meth)acryl group in one molecule (hereinafter, sometimes referred to as "acrylic monomer") as the main constituent monomer component (the main component of the monomer, i.e., the component that accounts for more than 50% by weight of the total amount of monomers constituting the acrylic polymer). The above-mentioned "(meth)acryl" means including acryl and methacryl. Similarly, the so-called "(meth)acrylate" means including acrylate and methacrylate.

(Acrylic polymer) The acrylic polymer as the base polymer of the acrylic adhesive is typically a polymer having (meth)acrylic acid alkyl ester as the main monomer component. As the (meth)acrylic acid alkyl ester, for example, a compound represented by the following formula (1) can be preferably used. CH ₂ =C(R ¹ )COOR ² (1) Here, R ¹ in the above formula (1) is a hydrogen atom or a methyl group. R ² is an alkyl group having 1 to 20 carbon atoms (including a chain alkyl group and an alicyclic alkyl group). In order to easily obtain an adhesive having excellent adhesive properties, preferably, ^R2 is an alkyl (meth)acrylate having a chain alkyl group (including a straight chain alkyl group and a branched alkyl group) having 1 to ₁₈ carbon atoms (hereinafter, this range of carbon atoms is sometimes expressed as C1-18), and more preferably, an alkyl (meth)acrylate having a chain alkyl group having _C1-14 . Specific examples of the C _1-14 chain alkyl group include methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl, n-heptyl, n-octyl, isooctyl, 2-ethylhexyl, n-nonyl, isononyl, n-decyl, isodecyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, etc. Examples of the alicyclic alkyl group that can be selected as R ² include cyclohexyl, isoindole, etc.

In some preferred embodiments, about 50% by weight or more, more preferably about 60% by weight or more, for example, about 70% by weight or more of the total amount of monomers used in the synthesis of the _acrylic polymer (hereinafter also referred to as "total raw material monomers") is selected from ^one or more of the (meth)acrylic acid alkyl esters (more preferably (meth)acrylic acid C _1-14 chain alkyl esters, and further preferably (meth)acrylic acid C _4-10 chain alkyl esters, such as one or both of n-butyl acrylate (BA) and 2-ethylhexyl acrylate (2EHA)) in which R 2 in the above formula (1) is a C 1-18 chain alkyl. The acrylic polymer obtained from such a monomer composition is easy to form an adhesive that exhibits adhesive properties suitable for use in liquid crystal display devices, and is therefore preferred. The ratio of the (meth)acrylic acid C _1-18 (e.g. C _1-14 , typically preferably C _4-10 ) chain alkyl ester to the total amount of the above-mentioned monomers is preferably approximately 95 wt % or less, preferably approximately 90 wt % or less, and more preferably 85 wt % or less (e.g. 80 wt % or less), from the viewpoint of introducing the functional group a or adjusting the phase difference or the refractive index.

In addition, in terms of adhesion characteristics, durability, adjustment of phase difference, adjustment of refractive index, etc., it is preferred to use (meth)acrylates having an aromatic ring structure as monomers used in the synthesis of acrylic polymers. Examples of the aromatic ring structure of (meth)acrylates having an aromatic ring structure include: benzene ring, naphthalene ring, thiophene ring, pyridine ring, pyrrole ring, furan ring, etc. Among them, (meth)acrylates having a benzene ring and a naphthalene ring are preferred. As (meth)acrylates having an aromatic ring structure, various (meth)acrylate aryl esters, (meth)acrylate aryl alkyl esters, (meth)acrylate aryloxyalkyl esters, etc. can be used.

Specific examples of (meth)acrylates having an aromatic ring structure include phenyl (meth)acrylate, o-phenylphenol (meth)acrylate, phenoxy (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxypropyl (meth)acrylate, benzyl (meth)acrylate, phenoxyethylene glycol (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, ethylene oxide-modified nonylphenol (meth)acrylate, ethylene oxide-modified cresol (meth)acrylate, phenol ethylene oxide-modified (Meth)acrylate, phenoxy-2-hydroxypropyl (meth)acrylate, methoxybenzyl (meth)acrylate, benzyl (meth)acrylate chloride, toluene (meth)acrylate, polystyrene (meth)acrylate, hydroxyethylated β-naphthol acrylate, 2-naphthyloxyethyl (meth)acrylate, 2-(4-methoxy-1-naphthyloxy)ethyl (meth)acrylate, thiophenyl (meth)acrylate, pyridinyl (meth)acrylate, pyrrole (meth)acrylate, polystyrene (meth)acrylate, etc. Those having a biphenyl ring such as biphenyl (meth)acrylate can also be used. These can be used alone or in combination of two or more. Among them, phenoxyethyl (meth)acrylate and benzyl (meth)acrylate are more preferred.

When (meth)acrylates having an aromatic ring structure are used, their content is appropriately set according to the adhesive properties, optical properties, etc. The (meth)acrylates having an aromatic ring structure are preferably about 5% by weight or more of the total amount of monomers used in the synthesis of the acrylic polymer. From the perspective of well exerting the effect of (meth)acrylates having an aromatic ring structure (improving durability or improving uneven liquid crystal display), it is preferably about 10% by weight or more, and more preferably about 15% by weight or more (for example, about 20% by weight or more). The upper limit of the amount of (meth)acrylates having an aromatic ring structure is preferably about 30% by weight or less. Considering the adhesive properties or the grip of the adhesive layer, it is preferably less than about 30% by weight, and more preferably less than about 25% by weight (for example, less than 22% by weight).

As the acrylic polymer in the technology disclosed herein, it is preferable to use a copolymer of a monomer containing a functional group. As preferred examples of monomers containing functional groups, there can be listed: carboxyl group-containing monomers, acid anhydride group-containing monomers, and hydroxyl group-containing monomers. These can be used alone or in combination of two or more. The above-mentioned monomers containing functional groups become cross-linking points in the adhesive layer, or can improve the cohesion or heat resistance of the adhesive. In addition, the adhesion between the conductive layer and the adhesive layer can be improved. By using an appropriate amount of monomers containing functional groups, the glass transition temperature (Tg) of the acrylic polymer can also be adjusted to adjust the adhesion characteristics.

Examples of monomers containing a carboxyl group include ethylenically unsaturated monocarboxylic acids such as acrylic acid (AA), methacrylic acid (MAA), carboxyethyl (meth)acrylate, and carboxypentyl (meth)acrylate; and ethylenically unsaturated dicarboxylic acids such as itaconic acid, succinic acid, fumaric acid, butenoic acid, isomethalic acid, and methylsuccinic acid. Examples of monomers containing anhydride groups include succinic anhydride, itaconic anhydride, and anhydrides of the above-mentioned ethylenically unsaturated dicarboxylic acids. Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxyhexyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxybutyl (meth)acrylate, and 12-hydroxyoctyl (meth)acrylate. (meth)acrylates such as hydroxy alkyl (meth)acrylates, such as decyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, (4-hydroxymethylcyclohexyl)methyl (meth)acrylate; alkylene glycol (meth)acrylates such as polyethylene glycol mono(meth)acrylate and polypropylene glycol mono(meth)acrylate; unsaturated alcohols such as vinyl alcohol, allyl alcohol, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, and diethylene glycol monovinyl ether; etc. These functional group-containing monomers may be used alone or in combination of two or more.

The acrylic polymer in the technology disclosed herein can be copolymerized with monomers containing functional groups other than those mentioned above. Such monomers can be used, for example, for purposes such as adjusting the Tg of the acrylic polymer and adjusting the adhesive properties. For example, as monomers that can improve the cohesive force or heat resistance of the adhesive, monomers containing sulfonic acid groups, monomers containing phosphoric acid groups, monomers containing cyano groups, etc. can be listed. In addition, as monomers that can be introduced into the acrylic polymer as functional groups that can become crosslinking bases or can help improve the adhesion with adherends such as glass, monomers containing amide groups, monomers containing amino groups, monomers containing imide groups, monomers containing epoxy groups, monomers having a ring containing nitrogen atoms, monomers containing ketone groups, monomers containing isocyanate groups, monomers containing alkoxysilyl groups, etc. can be listed. Among them, the amide group-containing monomers, amine group-containing monomers, and monomers having a nitrogen atom-containing ring as exemplified below are preferably used.

Monomers containing amide groups: for example, (meth)acrylamide, N,N-dimethyl (meth)acrylamide, n-butyl (meth)acrylamide, N-hydroxymethyl (meth)acrylamide, N-hydroxymethylpropane (meth)acrylamide, N-methoxymethyl (meth)acrylamide, N-butoxymethyl (meth)acrylamide. Monomers containing amino groups: for example, aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, N,N-dimethylaminopropyl (meth)acrylate, tert-butylaminoethyl (meth)acrylate. Monomers having a ring containing a nitrogen atom: for example, N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpiperidone, N-vinylpyrrolidone, N-vinylpyrrole, N-vinylimidazole, N-vinyloxazole, N-vinylmorpholine, N-vinylcaprolactam, N-(methyl)acryloylmorpholine, N-(methyl)acryloylpyrrolidone. Furthermore, among the above-mentioned monomers having a ring containing a nitrogen atom, there are of course monomers such as N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylcaprolactam, N-(methyl)acryloylmorpholine, N-(methyl)acryloylpyrrolidone that are equivalent to monomers containing an amide group. The same applies to the relationship between the above-mentioned monomer having a ring containing a nitrogen atom and the monomer containing an amine group.

The content of the functional group-containing monomer is not particularly limited, and is generally less than 40% by weight, preferably less than 30% by weight, based on the total amount of monomers used in the synthesis of the base polymer (typically an acrylic polymer). From the perspective of adhesion properties, it is preferably less than 20% by weight, more preferably less than 15% by weight, and further preferably less than 10% by weight (e.g., less than 5% by weight). The lower limit of the content of the functional group-containing monomer in the total amount of monomers used in the synthesis of the base polymer is generally greater than 0.001% by weight, preferably greater than 0.01% by weight, and from the perspective of better exerting the effect of copolymerization of the functional group-containing monomer, it is preferably greater than 0.1% by weight, more preferably greater than 0.5% by weight, and further preferably greater than 1% by weight.

In some preferred embodiments, at least one (preferably both) of a carboxyl group-containing monomer and a hydroxyl group-containing monomer is used as a monomer component of a base polymer (typically an acrylic polymer). When a carboxyl group-containing monomer is used as a monomer component of an acrylic polymer, the amount of the carboxyl group-containing monomer is generally about 0.001% by weight or more, preferably about 0.01% by weight or more, more preferably about 0.1% by weight or more, more preferably about 0.2% by weight or more, for example, it may be 1% by weight or more, or it may be 3% by weight or more, based on the total amount of monomers used in the synthesis of the base polymer, from the perspective of the cohesiveness and grip of the adhesive. The upper limit of the amount of carboxyl-containing monomer used is appropriately set in a manner to obtain the desired adhesive properties, and is preferably approximately 10 wt% or less, preferably approximately 8 wt% or less, and more preferably approximately 6 wt% or less, for example, approximately 3 wt% or less, and may also be approximately 1 wt% or less, based on the total amount of monomers used in the synthesis of the base polymer.

When a hydroxyl-containing monomer is used as a monomer component of a base polymer (typically an acrylic polymer), the amount of the hydroxyl-containing monomer is generally about 0.001% by weight or more, preferably about 0.01% by weight or more, and more preferably about 0.1% by weight or more, based on the total amount of monomers used in the synthesis of the base polymer, from the viewpoint of the cohesiveness and grip of the adhesive. The upper limit of the amount of the hydroxyl-containing monomer used is appropriately set in order to obtain the desired adhesive properties, and is preferably about 5% by weight or less, preferably about 3% by weight or less, and more preferably about 1% by weight or less (e.g., about 0.5% by weight or less) of the total amount of monomers used in the synthesis of the base polymer.

As other copolymerizable monomers that can be used in addition to the above-mentioned monomers containing functional groups, there can be listed: vinyl ester monomers such as vinyl acetate and vinyl propionate; aromatic vinyl ester compounds such as styrene, substituted styrenes (α-methylstyrene, etc.), and vinyl toluene; (meth)acrylates containing non-aromatic rings such as cyclohexyl (meth)acrylate, tert-butylcyclohexyl (meth)acrylate, cyclopentyl (meth)acrylate, and isobutyl (meth)acrylate; olefin monomers such as ethylene, propylene, isoprene, butadiene, and isobutylene; chlorine-containing monomers such as vinyl chloride and butylidene chloride; alkoxy-containing monomers such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate; vinyl ether monomers such as methyl vinyl ether, ethyl vinyl ether, and isobutyl vinyl ether; etc. These monomers can be used alone or in combination of two or more. When such other copolymerizable monomers are used, their usage is not particularly limited, and is usually preferably less than about 30% by weight (e.g., 0 to 30% by weight), and preferably less than about 10% by weight (e.g., less than about 3% by weight), of the total amount of monomers used in the synthesis of the base polymer (typically, an acrylic polymer). The technology disclosed herein can also be implemented in a state where the monomer components used in the synthesis of the base polymer do not substantially contain the above-mentioned other copolymerizable monomers.

As other examples of copolymerizable monomers that can constitute the base polymer (typically an acrylic polymer), polyfunctional monomers can be cited. Specific examples of polyfunctional monomers include compounds having two or more (meth)acryl groups in one molecule, such as 1,6-hexanediol di(meth)acrylate, ethylene glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, trihydroxymethylpropane tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and methylene diacrylamide. Polyfunctional monomers can be used alone or in combination of two or more. When such polyfunctional monomers are used, there is no particular limitation on the amount used, and it is usually preferably less than approximately 2% by weight (more preferably less than approximately 1% by weight) of the total amount of monomers used in the synthesis of the base polymer.

The initiator used for the polymerization can be appropriately selected from known or commonly used polymerization initiators. For example, azo-based polymerization initiators such as 2,2'-azobisisobutyronitrile can be preferably used. Other examples of polymerization initiators include: peroxide-based initiators (persulfates such as potassium persulfate, benzoyl peroxide, hydrogen peroxide, etc.); substituted ethane-based initiators such as phenyl-substituted ethane; aromatic carbonyl compounds; etc. As further examples of polymerization initiators, redox-based initiators composed of a combination of a peroxide and a reducing agent can be listed. Examples of the redox initiator include a combination of peroxide and ascorbic acid (a combination of hydrogen peroxide and ascorbic acid, etc.), a combination of peroxide and iron (II) salt (a combination of hydrogen peroxide and iron (II) salt, etc.), and a combination of persulfate and sodium bisulfite.

Such polymerization initiators may be used alone or in combination of two or more. The amount of the polymerization initiator used may be a normal amount, for example, 0.005 to 1 part by weight (typically 0.01 to 1 part by weight) per 100 parts by weight of the total raw monomers.

The method for obtaining the base polymer (typically an acrylic polymer) having the monomer composition is not particularly limited, and various polymerization methods such as solution polymerization, emulsion polymerization, bulk polymerization, and suspension polymerization can be used. Alternatively, active energy ray irradiation polymerization such as photopolymerization by irradiation with UV light (typically performed in the presence of a photopolymerization initiator), or radiation polymerization by irradiation with radiation such as β rays and γ rays can be used. From the perspective of transparency or adhesion performance, solution polymerization is preferably used. As a monomer supply method during polymerization, a one-time addition method in which all monomer raw materials are supplied at once, a continuous supply (drip) method, a batch supply (drip) method, etc. can be appropriately used. The polymerization temperature can be appropriately selected according to the types of monomers and solvents used, the types of polymerization initiators, etc., and can be set to about 20°C to 170°C (typically 40°C to 140°C). In addition, the synthesized base polymer can be a random copolymer, a block copolymer, a graft copolymer, etc. From the perspective of productivity, etc., a random copolymer is usually preferred.

As the solvent (polymerization solvent) used for solution polymerization, for example, any one solvent selected from aromatic compounds (typically aromatic hydrocarbons) such as toluene and xylene; acetates such as ethyl acetate; aliphatic or alicyclic hydrocarbons such as hexane; halogenated alkanes such as 1,2-dichloroethane; lower alcohols such as isopropanol (for example, monohydric alcohols having 1 to 4 carbon atoms); ethers such as tert-butyl methyl ether; ketones such as methyl ethyl ketone; etc., or a mixed solvent of two or more thereof can be used.

The base polymer (acrylic polymer) in the technology disclosed herein preferably has a weight average molecular weight (Mw) of about 10×10 ⁴ or more, obtained by GPC (gel permeation chromatography) in terms of standard polystyrene conversion. From the viewpoints of durability and heat resistance, it is preferably about 50×10 ⁴ or more, more preferably about 80×10 ⁴ or more, and further preferably about 120×10 ⁴ or more (e.g., about 150×10 ⁴ or more). In addition, the above Mw is preferably about 500×10 ⁴ or less, and from the viewpoints of coating properties when forming an adhesive layer, it is preferably about 300×10 ⁴ or less, more preferably about 250×10 ⁴ or less, and further preferably about 200×10 ⁴ or less.

Specifically, the above Mw can be measured under the following conditions using the trade name "HLC-8120GPC" (manufactured by Tosoh Corporation) as a GPC measuring device. [GPC measurement conditions] Sample concentration: 0.2 wt% (tetrahydrofuran solution) Sample injection volume: 100 μL Eluent: tetrahydrofuran (THF) Flow rate: 0.8 mL/min Column temperature (measurement temperature): 40°C Column: G7000H _XL + GMH _XL + GMH _XL manufactured by Tosoh Corporation Column size: 7.8 mm each ×30 cm, total 90 cm Detector: Differential Refractometer (RI) Standard Sample: Polystyrene

(Conductive component) The technology disclosed herein can be preferably implemented in a state where the adhesive layer contains a conductive component. As the above-mentioned antistatic component, an ionic compound is exemplified. The conductive agent that can be contained in the above-mentioned conductive layer can also be used. These conductive components can be used alone or in combination of two or more. In some preferred embodiments, the adhesive layer contains an ionic compound. The ionic compound preferably improves the conductivity of the adhesive layer as a conductive component. For example, it is preferred to use one or more selected from alkali metal salts or organic cation-anion salts. From the perspective of gripping properties, organic cation-anion salts are more preferred.

(Alkali metal salt) As the alkaline metal salt, organic salts and inorganic salts of alkaline metals can be used. Alkaline metal ions constituting the cation portion of the alkaline metal salt include lithium, sodium, and potassium ions. Among these alkaline metal ions, lithium ions are preferred.

The anion portion of an alkaline metal salt may contain either organic or inorganic substances. Examples of the anion portion constituting the organic salt include CH ₃ COO ^- , CF ₃ COO ^- , CH ₃ SO ₃ ^- , CF ₃ SO ₃ ^- , (CF ₃ SO ₂ ) ₃ C ^- , C ₄ F ₉ SO ₃ ^- , C ₃ F ₇ COO ^- , (CF ₃ SO ₂ )(CF ₃ CO)N ^- , (FSO ₂ ) ₂ N ^- , ^-O ₃ S(CF ₂ ) ₃ SO ₃ ^- , PF ₆ ^- , CO ₃ ^2- or the following general formulas (1) to (4): (1) (C _n F _2n+1 SO ₂ ) ₂ N ^- (wherein n is an integer of 1 to 10); (2) CF ₂ (C _m F _2m SO ₂ ) ₂ N ^- (wherein m is an integer of 1 to 10); (3) ^- O ₃ S(CF ₂ ) _l SO ₃ ^- (wherein l is an integer of 1 to 10); (4) (C _p F _2p+1 SO ₂ )N ^- (C _q F _2q+1 SO ₂ ) (wherein p and q are integers of 1 to 10); those represented by the above, etc. An ionic compound containing a fluorine atom in the anion part is preferably used because of its good ion dissociation property. As the inorganic anion part, Cl ^- , Br ^- , I ^- , AlCl ₄ ^- , Al ₂ Cl ₇ ^- , BF ₄ ^- , PF ₆ ^- , ClO ₄ ^- , NO ₃ ^- , AsF ₆ ^- , SbF ₆ ^- , NbF ₆ ^- , TaF ₆ ^- , (CN) ₂ N ^- and the like are used. As the anion part, (perfluoroalkylsulfonyl)imide such as (CF ₃ SO ₂ ) ₂ N ^- and (C ₂ F ₅ SO ₂ ) ₂ N ^- is preferred, and (trifluoromethanesulfonyl)imide represented by (CF ₃ SO ₂ ) ₂ N ^- is particularly preferred.

Specifically, organic salts of alkaline metals include sodium acetate, sodium alginate, sodium lignin sulfonate, sodium toluene sulfonate, LiCF ₃ SO ₃ , Li(CF ₃ SO ₂ ) ₂ N, Li(CF ₃ SO ₂ ) ₂ N, Li(C ₂ F ₅ SO ₂ ) ₂ N, Li(C ₄ F ₉ SO ₂ ) ₂ N, Li(CF ₃ SO ₂ ) ₃ C, KO ₃ S(CF ₂ ) ₃ SO ₃ K, LiO ₃ S(CF ₂ ) ₃ SO ₃ K, and the like. Among them, preferred are LiCF ₃ SO ₃ , Li(CF ₃ SO ₂ ) ₂ N, Li(C ₂ F ₅ SO ₂ ) ₂ N, Li(C ₄ F ₉ SO ₂ ) ₂ N, Li(CF ₃ SO ₂ ) ₃ C, etc., more preferred are fluorine-containing lithium imide salts such as Li(CF ₃ SO ₂ ) ₂ N, Li(C ₂ F ₅ SO ₂ ) ₂ N, Li(C ₄ F ₉ SO ₂ ) ₂ N, etc., and particularly preferred are (perfluoroalkylsulfonyl)imide lithium salts. Examples of the inorganic salt of the alkaline metal include lithium perchlorate and lithium iodide. The above alkaline metal salts may be used alone or in combination of two or more.

(Organic cation-anion salt) The so-called "organic cation-anion salt" used in the technology disclosed herein refers to an organic salt whose cation component includes organic matter, and the anion component can be organic or inorganic.

Specifically, the cationic component constituting the organic cation-anionic salt includes pyridinium cation, piperidinium cation, pyrrolidinium cation, cation having a pyrroline skeleton, cation having a pyrrole skeleton, imidazolium cation, tetrahydropyrimidinium cation, dihydropyrimidinium cation, pyrazolium cation, pyrazolinium cation, tetraalkylammonium cation, trialkylsiron cation, tetraalkylphosphonium cation, and the like.

Examples of anion components of the organic cation-anion salt include Cl ^- , Br ^- , I ^- , AlCl ₄ ^- , Al ₂ Cl ₇ ^- , BF ₄ ^- , PF ₆ ^- , ClO ₄ ^- , NO ₃ ^- , CH ₃ COO ^- , CF ₃ COO ^- , CH ₃ SO ₃ ^- , CF ₃ SO ₃ ^- , (CF ₃ SO ₂ ) ₃ C ^- , AsF ₆ ^- , SbF ₆ ^- , NbF ₆ ^- , TaF ₆ ^- , (CN) ₂ N ^- , C ₄ F ₉ SO ₃ ^- , C ₃ F ₇ COO ^- , (CF ₃ SO ₂ )(CF ₃ CO)N ^- , (FSO ₂ ) ₂ N ^- , ^-O ₃ S(CF ₂ ) ₃ SO ₃ ^- or the following general formulas (1) to (4): (1) (C _n F _2n+1 SO ₂ ) ₂ N ^- (where n is an integer of 1 to 10); (2) CF ₂ (C _m F _2m SO ₂ ) ₂ N ^- (where m is an integer of 1 to 10); (3) ^- O ₃ S(CF ₂ ) _l SO ₃ ^- (where l is an integer of 1 to 10); (4) (C _p F _2p+1 SO ₂ )N ^- (C _q F _2q+1 SO ₂ ) (where p and q are integers of 1 to 10); and the like. An ionic compound containing fluorine atoms as an anionic component is preferably used because of its good ionic dissociation property. The total number of carbon atoms of the fluoroalkyl group possessed by the anionic component is preferably 1 to 3, more preferably 1 or 2. The plasma compound may be used alone or in combination of two or more.

(Other ionic compounds) In addition to the above-mentioned alkali metal salts and organic cation-anion salts, inorganic salts such as ammonium chloride, aluminum chloride, cupric chloride, ferrous chloride, ferric chloride, and ammonium sulfate may also be used as ionic compounds. In addition, the ionic compounds disclosed herein include those generally referred to as ionic surfactants. As ionic surfactants, there can be listed: cationic surfactants having cationic functional groups such as quaternary ammonium salts, phosphonium salts, cobalt salts, pyridinium salts, and amine groups; anionic surfactants having anionic functional groups such as carboxylic acids, sulfonates, sulfates, phosphates, and phosphites; amphoteric surfactants such as sulfobetaines and their derivatives, alkylbetaines and their derivatives, imidazolines and their derivatives, alkylimidazoliumbetaines and their derivatives; etc. Organic cationic-anionic salts may be used alone or in combination of two or more.

As the ionic compound, there can be ionic solids and ionic liquids, and it is preferable to use ionic liquids. Ionic liquids are easy to move in the adhesive layer and are easy to be evenly dispersed in the layer. When an ionic liquid is used as the ionic compound, the effect of the technology disclosed herein tends to be better exerted.

Furthermore, the so-called "ionic liquid" refers to a molten salt that is liquid at a temperature below 40°C. In the temperature range where the ionic liquid is liquid, it is easier to add, disperse or dissolve in the adhesive than a solid salt. Furthermore, the ionic liquid has the following characteristics: no vapor pressure (non-volatile), so it does not disappear over time and can continuously obtain antistatic properties. The ionic liquid used in the technology disclosed here is preferably a molten salt that is liquid at room temperature (25°C). Among the above-mentioned ionic compounds, organic cation-anion salts (ionic liquids of organic cation-anion salts) that are liquid at 40°C or below are preferred, and organic cation-anion salts (ionic liquids of organic cation-anion salts) that are liquid at room temperature (25°C) are more preferred.

The content of the ionic compound (preferably an organic cationic-anionic salt) in the adhesive layer is not particularly limited, and can be added in an appropriate amount to impart specific conductivity to the adhesive layer. The amount of the ionic compound is preferably set to approximately 0.01 parts by weight or more (e.g., approximately 0.05 parts by weight or more) relative to 100 parts by weight of the base polymer (e.g., acrylic polymer). From the perspective of improving conductivity, it is preferably approximately 0.1 parts by weight or more, more preferably approximately 0.3 parts by weight or more, further preferably approximately 0.5 parts by weight or more, and particularly preferably approximately 0.7 parts by weight or more. In addition, the upper limit of the amount of the ionic compound is preferably set to approximately 20 parts by weight or less relative to 100 parts by weight of the base polymer. Considering durability or adhesion properties, it is preferably approximately 10 parts by weight or less, more preferably approximately 5 parts by weight or less, and further preferably approximately 3 parts by weight or less (for example, approximately 2 parts by weight or less).

The content of the conductive component in the adhesive layer (including the total amount of the conductive component of the ionic compound) is not particularly limited, and can be added in an appropriate amount to give the adhesive layer a specific conductivity. The amount of the conductive component is preferably set to approximately 0.01 parts by weight or more relative to 100 parts by weight of the base polymer (e.g., acrylic polymer). From the perspective of improving conductivity, it is preferably approximately 0.1 parts by weight or more, and more preferably approximately 0.5 parts by weight or more. In addition, the upper limit of the amount of the conductive component is preferably set to approximately 30 parts by weight or less relative to 100 parts by weight of the base polymer. Considering durability or adhesive properties, it is preferably approximately 10 parts by weight or less, more preferably approximately 5 parts by weight or less, and further preferably approximately 3 parts by weight or less. In the case where an ionic compound is used as the conductive component, the adhesive layer may contain, in addition to the ionic compound, any conductive component other than the ionic compound, or may contain substantially no conductive component. Furthermore, the technology disclosed herein may be implemented in the case where the adhesive layer substantially contains no conductive component other than the ionic compound.

(Adhesive composition) In the technology disclosed herein, the form of the adhesive composition used to form the adhesive layer is not particularly limited. For example, it may be an adhesive composition in a form in which an adhesive component is contained in an organic solvent (solvent-type adhesive composition), an adhesive composition in a form in which an adhesive component is dispersed in an aqueous solvent (a water-dispersible adhesive composition, typically an aqueous emulsion-type adhesive composition), a solvent-free adhesive composition (for example, an adhesive composition of a type that is hardened by irradiation with active energy rays such as ultraviolet rays or electron beams, a hot-melt adhesive composition), etc. The technology disclosed herein can be preferably implemented in a form having an adhesive layer formed by a solvent-type adhesive composition. The organic solvent contained in the solvent-type adhesive composition may be, for example, a single solvent including any one of toluene, xylene, ethyl acetate, hexane, cyclohexane, methylcyclohexane, heptane and isopropanol, or a mixed solvent containing any one of these as a main component.

In the technology disclosed herein, the adhesive composition (preferably a solvent-type adhesive composition) used for forming the adhesive layer can preferably be formed in a manner that enables the base polymer (typically an acrylic polymer) contained in the composition to be appropriately crosslinked. As a specific crosslinking method, it is preferred to use a method in which a crosslinking point is introduced into the base polymer in advance by copolymerizing a monomer having an appropriate functional group (hydroxyl group, carboxyl group, etc.), and a compound (crosslinking agent) that can react with its functional group to form a crosslinked structure is added to the base polymer for reaction.

Examples of the crosslinking agent include isocyanate crosslinking agents, epoxy crosslinking agents, oxazoline crosslinking agents, aziridine crosslinking agents, melamine crosslinking agents, carbodiimide crosslinking agents, hydrazine crosslinking agents, amine crosslinking agents, imine crosslinking agents, peroxide crosslinking agents (e.g., benzoyl peroxide), metal chelate crosslinking agents (typically, polyfunctional metal chelates), metal alkoxide crosslinking agents, and metal salt crosslinking agents. The crosslinking agent may be used alone or in combination of two or more. Among them, isocyanate crosslinking agents, epoxy crosslinking agents, peroxide crosslinking agents, and metal chelate crosslinking agents are preferred. For example, when an acrylic polymer is used as the base polymer, isocyanate crosslinking agents and peroxide crosslinking agents are preferred, and a combination of isocyanate crosslinking agents and peroxide crosslinking agents is more preferred.

The amount of the crosslinking agent used can be appropriately selected according to the composition and structure (molecular weight, etc.) of the base polymer (e.g., acrylic polymer) or the purpose of the liquid crystal display device. Generally, the amount of the crosslinking agent used is preferably about 0.01 parts by weight or more relative to 100 parts by weight of the base polymer. From the perspective of improving the cohesive force of the adhesive, it is preferably about 0.02 parts by weight or more, and more preferably about 0.03 parts by weight or more (e.g., 0.1 parts by weight or more). The upper limit of the amount of the crosslinking agent used is usually preferably about 10 parts by weight or less relative to 100 parts by weight of the base polymer. From the perspective of wettability to the adherend, it is preferably about 5 parts by weight or less, more preferably about 3 parts by weight or less, and further preferably about 1 part by weight or less.

The above adhesive composition can be further formulated with various additives as needed. Examples of such additives include: surface lubricants, leveling agents, plasticizers, softeners, fillers, antioxidants, preservatives, light stabilizers, ultraviolet absorbers, polymerization inhibitors, crosslinking promoters, silane coupling agents, etc. In addition, in the adhesive composition with acrylic polymer as the base polymer, a well-known or commonly used adhesive imparting resin or stripping regulator can also be formulated. Furthermore, when the adhesive polymer is synthesized by emulsion polymerization, it is preferred to use an emulsifier or a chain transfer agent (also called a molecular weight regulator or a polymerization degree regulator). The content of the additives as the optional components can be appropriately determined according to the purpose of use. The amount of the optional additives used is generally about 5 parts by weight or less, preferably about 3 parts by weight or less (e.g., about 1 part by weight or less) relative to 100 parts by weight of the base polymer.

(Method for forming adhesive layer) The adhesive layer can be formed, for example, by applying the above-mentioned adhesive composition directly to the polarizing film or to the conductive layer provided on the polarizing film, and drying or curing it (direct method). Alternatively, the adhesive layer can be formed by applying the above-mentioned adhesive composition to the surface of the peeling pad (peeling surface), drying or curing it, and forming the adhesive layer on the surface, and then attaching the adhesive layer to the polarizing film or to the surface of the conductive layer provided on the polarizing film to transfer the adhesive layer (transfer method). When applying (typically coating) the adhesive composition, various methods such as roll coating and gravure coating can be appropriately used. The adhesive composition can be dried under heating as needed. As a method for curing the adhesive composition, ultraviolet rays, laser rays, α rays, β rays, γ rays, X-rays, electron beams, etc. can be appropriately used.

(Surface resistance of adhesive layer) The surface resistance of the adhesive layer is not particularly limited. In some preferred embodiments, by configuring not only the conductive layer but also the adhesive layer to have conductivity, a higher conductivity can be imparted to the visual side of the liquid crystal display device. In this embodiment, the surface resistance of the adhesive layer is preferably approximately 1×10 ¹² Ω/□ or less from the perspective of anti-static and the like. If an adhesive layer whose surface resistance is limited to a specific value or less is used for liquid crystal panels (e.g., embedded liquid crystal panels), the generation of static unevenness can be well prevented based on its conductivity. In addition, from the viewpoint of the sensitivity or durability of the touch sensor, the lower limit of the surface resistance value is preferably about 1×10 ⁷ Ω/□ or more. From the viewpoint of the above, for example, when applied to the following surface embedded liquid crystal unit, the surface resistance value is preferably about 1×10 ¹⁰ Ω/□ to 1×10 ¹² Ω/□. In addition, when applied to the following semi-embedded liquid crystal unit, the surface resistance value is preferably about 1×10 ⁹ Ω/□ to 1×10 ¹² Ω/□. Furthermore, when applied to the following embedded liquid crystal unit, the surface resistance value is preferably about 1×10 ⁷ Ω/□ to 1×10 ¹² Ω/□, and from the viewpoint of durability, it is more preferably about 1×10 ⁸ Ω/□ to 1×1012 Ω/□. The surface resistance of the adhesive layer is measured by the method described in the examples described below.

(Thickness of adhesive layer) Although not particularly limited, the thickness of the adhesive layer can be set to, for example, approximately 1 μm or more, and is usually preferably set to approximately 3 μm or more. From the perspective of antistatic properties or durability, and ensuring the contact area with the conductive path when the conductive path is set on the side, the thickness of the adhesive layer is preferably approximately 5 μm or more, more preferably approximately 7 μm or more, and further preferably approximately 10 μm or more. The above thickness can be set to, for example, approximately 100 μm or less, and is usually preferably approximately 50 μm or less (e.g. approximately 35 μm or less).

<Constitutional materials of liquid crystal panel> As a liquid crystal layer constituting a liquid crystal unit, a liquid crystal layer containing liquid crystal molecules is used. In some embodiments, the liquid crystal layer is a liquid crystal layer containing horizontally aligned liquid crystal molecules in the absence of an electric field. As a liquid crystal layer, for example, an IPS type liquid crystal layer is preferably used. As other examples of liquid crystal layers that can be used in the technology disclosed herein, there can be listed: TN type or STN type, π type, VA type, etc. liquid crystal layers. The thickness of the liquid crystal layer is, for example, about 1.5 μm to 4 μm.

The detection electrode and the driving electrode (including the integration of the two) constituting the touch sensing electrode part are typically transparent conductive layers (transparent electrodes). The materials of these electrodes are not particularly limited, and for example, one or more metals such as gold, silver, copper, platinum, palladium, aluminum, nickel, chromium, titanium, iron, cobalt, tin, magnesium, tungsten, or alloys of these metals can be used. In addition, as electrode materials, one or more metal oxides of indium, tin, zinc, gallium, antimony, zirconium, and cadmium can be used. As specific examples, metal oxides including indium oxide, tin oxide, titanium oxide, cadmium oxide, and mixtures thereof can be listed. Other metal compounds including copper iodide and the like may also be used. The above metal oxide may further include oxides of the metal atoms listed above as needed. For example, indium oxide (ITO) containing tin oxide, tin oxide containing antimony, etc. are preferably used, and ITO is particularly preferred. As ITO, it is preferred to use one containing approximately 80 to 99% by weight of indium oxide and approximately 1 to 20% by weight of tin oxide.

In an embedded type liquid crystal panel, the detection electrode and the driving electrode as the touch sensing electrode part are usually formed as a transparent electrode pattern on the inner side (the liquid crystal layer side in the liquid crystal cell) of at least one (typically only one) of the first transparent substrate and the second transparent substrate. In a semi-embedded type liquid crystal panel, one of the detection electrode and the driving electrode is formed on the inner side (the liquid crystal layer side in the liquid crystal cell) of one of the first transparent substrate and the second transparent substrate, and the other of the detection electrode and the driving electrode is formed on the outer side of the other of the first transparent substrate and the second transparent substrate. In the embedded type liquid crystal panel, the detection electrode, the driving electrode, and the electrode formed in one piece are formed outside the first transparent substrate and the second transparent substrate (outside the liquid crystal unit). The above electrode pattern is formed by a conventional method. Furthermore, the detection electrode, the driving electrode, and the electrode formed in one piece in the touch sensing electrode part can also function as a common electrode for controlling the liquid crystal layer.

The electrode pattern is usually electrically connected to a lead (not shown) formed at the end of the transparent substrate. The lead is connected to a controller IC (not shown). The shape of the electrode pattern is not limited to the orthogonal stripe wiring in the above-mentioned configuration example. For example, in addition to the stripe shape, any shape such as a comb shape or a diamond shape can be selected according to the use and purpose. Therefore, the so-called detection electrode and the driving electrode can have a cross pattern other than a right angle or various other patterns. The height of the electrode pattern can be, for example, approximately 10 nm to 100 nm, and the width can be approximately 0.1 mm to 5 mm.

As materials for forming the transparent substrate (including the first and second transparent substrates), for example, glass or polymer films can be cited. Therefore, the transparent substrate can be a glass substrate or a polymer substrate. As the glass used for the transparent substrate, various glass materials can be used without particular limitation. As polymer films, for example, polyethylene terephthalate (PET), polycycloolefin, polycarbonate, etc. can be cited. In the case where the main body of the transparent substrate is formed by a glass plate, its thickness is, for example, about 0.1 mm to 1 mm. In the case where the main body of the transparent substrate is formed by a polymer film, its thickness is, for example, about 10 μm to 200 μm. The transparent substrate may have an easy-to-adhesion layer or a hard coating layer on its surface.

As a material for forming a conductive structure connected to the side of the adhesive layer and the conductive layer, various conductive materials can be used without particular limitation. For example, it is preferable to use a conductive slurry such as a metal slurry containing one or more of silver, gold and other metals. As another example of the above-mentioned material, a conductive adhesive can be cited. The conductive structure can be a linear structure extending from the side of the conductive layer or adhesive layer. The material of the conductive structure that can be set on the side of the polarizing film is also the same as above and can be set to the same shape as above.

In the liquid crystal panel, the optical film as the optical film of the adhesive layer disposed on the side opposite to the viewing side may be the polarizing film disclosed herein or a known or conventional optical film different from the polarizing film, depending on the application or purpose. Examples of such optical films include: phase difference film (also called phase difference plate, including wavelength plate), optical compensation film, brightness enhancement film, light diffusion film, reflection film, anti-transmission film, etc. These may be used alone or in combination of two or more.

<Application> The application of the liquid crystal display device with built-in touch sensing function (also called touch panel type liquid crystal display device) disclosed herein is not particularly limited, and can be used for various applications such as portable electronic equipment and vehicle-mounted use. The technology disclosed herein is particularly suitable for vehicle-mounted touch panel type liquid crystal display devices that are easily exposed to harsh environments and require specific or higher moisture and heat durability. By applying the technology disclosed herein to the above-mentioned applications, excellent durability can be obtained based on improved moisture and heat conductivity stability.

The following describes several embodiments of the present invention, but it is not intended to limit the present invention to the specific embodiments. In addition, the "parts" and "%" in the following description are based on weight unless otherwise specified.

<Evaluation method> [Surface resistance of conductive layer] (1) Initial surface resistance For the surface of the conductive layer side of the polarizing film with conductive layer (before adhesive layer lamination) used in the manufacture of liquid crystal display devices, the initial surface resistance [Ω/□] was measured at a temperature of 23°C and 50% RH in accordance with JIS K 6911 under the conditions of applying a voltage of 10 V for 10 seconds. As a resistivity meter, the "Hiresta UP MCP-HT450" manufactured by Mitsubishi Chemical Analytical Technology Co., Ltd. or its equivalent can be used. (2) Surface resistance after wet heat test A polarizing film with a conductive layer (before adhesive layer deposition) used to manufacture a liquid crystal display device was placed in a wet heat environment at 85°C and 85%RH for 24 hours (wet heat test). After drying for 3 hours at room temperature, the surface of the conductive layer was tested for surface resistance [Ω/□] at 23°C and 50%RH for 10 seconds in accordance with JIS K 6911. As a resistivity meter, the "Hiresta UP MCP-HT450" manufactured by Mitsubishi Chemical Analytical Technology Co., Ltd. or its equivalent can be used. (3) Wet-heat surface resistance change ratio The wet-heat surface resistance change ratio is calculated from the ratio (S/P) of the surface resistance value S[Ω/□] after the wet-heat test to the initial surface resistance value P[Ω/□] obtained by the above measurement.

[Surface resistance of adhesive layer] An adhesive layer for manufacturing a liquid crystal display device was formed on a release pad. The surface resistance of the adhesive layer was measured at a temperature of 23°C and 50% RH in accordance with JIS K 6911 under the conditions of applying a voltage of 250V for 10 seconds. As a resistivity meter, a commercially available resistivity meter (e.g., "Hiresta UP MCP-HT450" manufactured by Mitsubishi Chemical Analytical Technology Co., Ltd.) or its equivalent can be used. In Table 1 described below, the case where the resistance value exceeds the upper limit of the measurement is recorded as "OVER".

[Wet-heat conductivity change ratio F _HT ] (1) Preliminary evaluation (correlation with surface resistance) Five samples of polarizing films with conductive layers having different surface resistance values were prepared, and each sample of polarizing films with conductive layers was installed in a touch panel evaluation kit (manufactured by Shurter Corporation under the product name "TouchKit"). The evaluation kit has a PCAP (projected electrostatic capacitive) touch panel laminated with a cover glass, an IC (integrated circuit) substrate, and software. The software can record and process the current value of the touch panel from the terminal connected to the touch panel through the IC substrate. As shown in FIG10, the polarizing film sample with a conductive layer is attached to the evaluation kit. Specifically, the adhesive layer surface of the polarizing film sample with a conductive layer S is attached to the cover glass 304 of the touch panel 302 of the evaluation kit 300 in a manner that does not produce bulges. The touch panel 302 is placed horizontally on an insulator (not shown). As an insulator, for example, a flat resin or a frame-shaped rubber body can be used. Furthermore, by using the software started by the PC, the capacitance data map of the touch panel 302 surface is obtained through the terminal T and the IC substrate, and ΔC is obtained in the form of the difference (processed data) between the current value of the touch panel obtained and the base current value of the touch panel when the polarizing film sample S without a conductive layer is attached. In this measurement, as ΔC, the processed data (Max-Min) calculated from the maximum and minimum values of the difference (processed data) between multiple measured values measured at multiple locations in the touch panel surface and the base current value is used. FIG11 is a graph obtained by plotting the sample with the above-measured ΔC (processed data (Max-Min)) as the vertical axis and the surface resistance value of the conductive layer [Ω/□] as the horizontal axis. As shown in FIG11, the above-mentioned ΔC and the surface resistance value [Ω/□] show a correlation coefficient R ² of 0.9701 in the regression line, which shows that the above-mentioned ΔC can be used as an indicator of the conductivity or conductivity change of the conductive layer. The above-mentioned ΔC is a value that has been digitally converted (8bit) in the above-mentioned software, so the unit is bit. The same is true for the following ΔC (A), ΔC (B) and the wet-heat conductivity change ratio F _HT . Furthermore, in the measurement of ΔC(A) and ΔC(B) described later, when the polarizing film sample with a conductive layer is installed in the evaluation kit, a plurality of insulating sheets (such as polystyrene sheets) may be overlapped on the upper surface (back surface) of the polarizing film sample with a conductive layer as weights to prevent a bulge from being generated between the polarizing film sample with a conductive layer and the cover glass 304. In addition, when a conductive layer (for example, a sample in which a conductive layer is formed on a PET film of an insulator) is directly mounted on an evaluation kit to carry out the measurement of ΔC(A) and ΔC(B) described later, the conductive layer is mounted in such a manner that the surface of the conductive layer is in contact with the cover glass of the evaluation kit. Then, a plurality of insulating sheets (for example, about 20 polystyrene sheets of the same size as the touch panel (each sheet weighing about 10 to 20 g)) are overlapped on the conductive layer as weights to prevent a bulge from being generated between the conductive layer and the cover glass. The other measurements can be carried out in the same manner as described above. As described above, regardless of whether the F _HT of the conductive layer is measured by using a polarizing film with a conductive layer as an evaluation kit with an adhesive layer interposed therebetween or when the conductive layer is directly in contact with the cover glass as an evaluation kit, _{the F HT obtains} a substantially consistent value without significant variation. (2) ΔC (A) The polarizing film with a conductive layer used to manufacture a liquid crystal display device is installed in the evaluation kit 300 by the same method as in (1) above, and the difference ΔC (processed data) between the current value of the touch panel when the polarizing film with a conductive layer is installed and the base current value of the touch panel is obtained based on the capacitance data graph obtained within the touch panel surface. It is used as the difference ΔC(A) between the current value flowing in the touch panel and the base current value of the touch panel when the conductive layer before the wet heat test is arranged on the touch panel for evaluation. Furthermore, as mentioned above, ΔC(A) can be measured directly using the conductive layer instead of the polarizing film with a conductive layer. (3) ΔC(B) In addition, the polarizing film with a conductive layer used to manufacture the liquid crystal display device is placed in a wet heat environment of 85°C and 85%RH for 24 hours (wet heat test). Afterwards, after drying for 3 hours at room temperature, the test kit 300 is installed in the same manner as in (1) above. Based on the capacitance data graph obtained on the surface of the touch panel, the difference ΔC (processed data) between the current value of the touch panel when the polarizing film with a conductive layer is installed and the base current value of the touch panel is obtained. This is used as the difference ΔC(B) between the current value flowing in the touch panel and the base current value of the touch panel when the conductive layer after the wet heat test is arranged on the evaluation touch panel. Furthermore, as described above, ΔC(B) can be measured directly using the conductive layer without using the polarizing film with a conductive layer. (4) Calculation of the thermal conductivity change ratio F _HT The thermal conductivity change ratio F _HT is calculated according to the following formula (1). F _HT = ΔC(B)/ΔC(A) ・・・・・(1)

[Evaluation of touch sensitivity stability] Based on the wet-heat conductivity change ratio F _HT , the evaluation was conducted according to the following criteria. (Evaluation criteria) ◎: F _HT ≦1.5 ○: 1.5＜F _HT ≦2 ×: 2＜F _HT

[ESD (electrostatic discharge) test] Prepare the embedded liquid crystal unit, peel off the peel pad from the polarizing film with a conductive layer, and stick the exposed adhesive surface to the visual side of the embedded liquid crystal unit as shown in Figure 1. Then, apply 5 mm wide silver paste on the side of the polarizing film with a conductive layer stuck to the embedded liquid crystal unit to cover the entire side of the hard coating layer, polarizing film, conductive layer, and adhesive layer, and connect it to the ground electrode from the outside, thereby obtaining a liquid crystal display panel. Under the conditions of 23℃ and 55%RH, the LCD panel was mounted on the backlight device, and an electrostatic discharge gun was used to apply a voltage of 10 kV to the polarizing film surface on the viewing side, and the time taken for the blank part caused by electricity to disappear was measured (initial evaluation). In addition, the LCD panel was placed in a wet and hot environment at a temperature of 85℃ and 85%RH for 24 hours, and then dried at room temperature for 3 hours, and the same ESD test was also implemented (wet and hot evaluation). The measurement results obtained were evaluated according to the following standards. (Evaluation criteria) ◎: White spots disappeared within 3 seconds both at the beginning and after wet heat treatment ○: White spots disappeared within 5 seconds but more than 3 seconds at the beginning or after wet heat treatment ×: White spots did not disappear within 5 seconds both at the beginning and after wet heat treatment

[Preparation of polarizing film] (Preparation example A1) A 30 μm thick polyvinyl alcohol (PVA) resin film (manufactured by Kuraray Co., Ltd., product name "PE3000") was stretched uniaxially to 5.9 times in the length direction using a roll stretching machine, and then subjected to swelling, dyeing, crosslinking, washing, and finally drying treatment, thereby obtaining a polarizing element with a thickness of 12 μm. Specifically, during the swelling treatment, the film was stretched to 2.2 times while being treated with pure water at 20°C. During the dyeing treatment, the film was stretched to 1.4 times while being treated at 30°C in an aqueous solution with an iodine concentration adjusted so that the monomer transmittance of the obtained polarizing element would be 45.0%. In the above aqueous solution, the weight ratio of iodine to potassium iodide is 1:7. As a crosslinking treatment, a two-stage crosslinking treatment is adopted. In the first stage of the crosslinking treatment, the membrane is stretched to 1.2 times while being treated in a boron/potassium iodide aqueous solution at 40°C. The boron content of the aqueous solution is set to 5.0%, and the potassium iodide content is set to 3.0%. In the second stage of the crosslinking treatment, the membrane is stretched to 1.6 times while being treated in a boron/potassium iodide aqueous solution at 65°C. The boron content of the aqueous solution is set to 4.3%, and the potassium iodide content is set to 5.0%. In the washing treatment, a potassium iodide aqueous solution at 20°C is used. The potassium iodide content of the aqueous solution for the washing treatment is set to 2.6%. The drying treatment is carried out at 70°C for 5 minutes.

A 32 μm thick TAC-HC film having a hard coating (HC) layer on one side of a triacetyl cellulose (TAC) film was bonded to one side of the polarizing element using a PVA-based adhesive. A 25 μm thick acrylic (CAT) film was bonded to the other side of the polarizing element using a PVA-based adhesive to prepare a polarizing film having a structure of TAC protective layer/PVA polarizing element/CAT protective layer. A hard coating layer as a surface treatment layer was provided on the TAC protective layer side of the polarizing film.

[Preparation of Conductive Composition] (Preparation Example B1) 14.3 parts of a solution containing a thiophene-based polymer (PEDOT/PSS-NH ₄ ), 1 part of an adhesive solution A (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., trade name "Superflex 210", containing a urethane adhesive, solid content rate of 35%), 4 parts of an adhesive solution B (manufactured by Nippon Catalyst Co., Ltd., trade name "Epocros WS-700", containing an oxazoline-containing polymer with Mn 20,000 and Mw 40,000), triethylene glycol (boiling point: about 287°C) as a high boiling point compound, and water were prepared to prepare a conductive composition B1 with a solid content concentration of 1.5%. As a solution containing a thiophene-based polymer, an aqueous dispersion containing PEDOT (poly(3,4-ethylenedioxythiophene)) and PSS (sodium poly(styrenesulfonate)) (manufactured by Heraeus, trade name "CleviosP") was used, which was neutralized with 28% ammonia water manufactured by Tokyo Chemical Industry Co., Ltd. and the solid content was adjusted to 1%. Triethylene glycol was prepared so as to be contained in the composition at 3%. The obtained composition contained 0.14% of the thiophene-based polymer, 0.36% of the urethane adhesive, and 1.0% of the oxazoline-based polymer.

(Preparation Example B2) The conductive composition B2 of this example was prepared in the same manner as Preparation Example B1 except that diethylene glycol (boiling point: about 244°C) was used instead of triethylene glycol as the high boiling point compound.

(Preparation Example B3) The conductive composition B3 of this example was prepared in the same manner as Preparation Example B1 except that o-catechin (boiling point: about 246°C) was used instead of triethylene glycol as the high boiling point compound.

(Preparation Example B4) The conductive composition B4 of this example was prepared in the same manner as Preparation Example B3, except that the amount of the high boiling point compound (o-catechol) added was changed from 3% to 10% and the amount of water was reduced accordingly.

(Preparation Example B5) The conductive composition B5 of this example was prepared in the same manner as Preparation Example B1 except that glycerol (boiling point: about 290°C) was used instead of triethylene glycol as the high boiling point compound.

(Preparation Example B6) The conductive composition B6 of this example was prepared in the same manner as Preparation Example B1 except that N-methylpyrrolidone (boiling point: about 204°C) was used instead of triethylene glycol as the high boiling point compound.

(Preparation Example B7) The conductive composition B7 of this example was prepared in the same manner as Preparation Example B1 except that 5% dimethyl sulfoxide (boiling point: about 189°C) was used instead of 3% triethylene glycol as the high boiling point compound and the amount of water was reduced accordingly.

(Preparation Example B8) The conductive composition B8 of this example was prepared in the same manner as Preparation Example B1 except that no high boiling point compound was used.

(Preparation Example B9) The conductive composition B9 of this example was prepared in the same manner as Preparation Example B1 except that N,N-dimethylformamide (boiling point: about 153°C) was used instead of triethylene glycol.

(Preparation Example B10) The conductive composition B10 of this example was prepared in the same manner as Preparation Example B1 except that diethylene glycol dimethyl ether (boiling point: about 162°C) was used instead of triethylene glycol.

[Preparation of adhesive composition] (Preparation Example C1) In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen inlet tube, and a cooler, a monomer mixture containing 76.9 parts of butyl acrylate (BA), 17 parts of benzyl acrylate (BzA), 5 parts of acrylic acid (AA), 1 part of N-vinyl-2-pyrrolidone (NVP), and 0.1 parts of 4-hydroxybutyl acrylate (4HBA) was added. Furthermore, 0.1 part of 2,2'-azobisisobutyronitrile as a polymerization initiator was added together with 100 parts of ethyl acetate with respect to 100 parts of the above-mentioned monomer mixture (solid content), and nitrogen was introduced while slowly stirring to replace the nitrogen atmosphere. The liquid temperature in the flask was maintained at approximately 55°C and a polymerization reaction was carried out for 8 hours to prepare an acrylic polymer P1 solution with Mw of 1.95 million and Mw/Mn=3.9.

To 100 parts of the solid content of the acrylic polymer P1 solution obtained above, 0.4 parts of an isocyanate crosslinking agent (manufactured by Tosoh Corporation, trade name "Coronate L", trihydroxymethylpropane/toluene diisocyanate adduct), 0.1 parts of a peroxide crosslinking agent (manufactured by NOF Corporation, trade name "Nyper BMT") and 0.2 parts of γ-glycidyloxypropyl methoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KBM-403") were mixed to prepare a solution of an acrylic adhesive composition C1.

(Preparation Example C2) 6 parts of a conductive agent were mixed with 100 parts of the solid content of the acrylic polymer P1 solution, and further 0.4 parts of an isocyanate crosslinking agent (manufactured by Tosoh Corporation, trade name "Coronate L", trihydroxymethylpropane/toluene diisocyanate adduct), 0.1 parts of a peroxide crosslinking agent (manufactured by NOF Corporation, trade name "Nyper BMT"), and 0.2 parts of γ-glycidyloxypropylmethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KBM-403") were mixed to prepare a solution of an acrylic adhesive composition C2. As a conductive agent, lithium bis(trifluoromethanesulfonyl)imide (Li-TFSI) was used.

<Examples 1 to 11 and Comparative Examples 1 to 3> On one side of the polarizing film (the side without the hard coating layer), a coating liquid containing any one of the conductive compositions B1 to B10 is applied to a thickness of 50 nm after drying, and dried at 80°C for 3 minutes to form a conductive layer. On one side of a polyethylene terephthalate (PET) film (peel pad, manufactured by Mitsubishi Chemical Polyester Film Co., Ltd., No. "MRF38") treated with a silicone peeling agent, a solution of any one of the acrylic adhesive compositions C1 to C2 was applied in such a manner that the thickness of the adhesive layer after drying became 23 μm, and dried at 155° C. for 1 minute to form an adhesive layer on the surface of the peel pad. Furthermore, the adhesive layer formed on the peel pad was transferred to the conductive layer side surface of the polarizing film obtained above. In this way, the polarizing film with a conductive layer of each example was prepared. The polarizing films with conductive layers have a structure of polarizing film/conductive layer/adhesive layer, and a hard coating layer is arranged on the back side of the polarizing film, and a peeling pad is used to protect the adhesive surface of the adhesive layer.

Next, the embedded liquid crystal unit is prepared, and the peelable pad is peeled off from the polarizing film with a conductive layer in each example, and the exposed adhesive surface is attached to the two sides of the embedded liquid crystal unit as shown in Figure 1. The lead wiring (not shown) around the transparent electrode pattern inside the embedded liquid crystal unit is connected to the controller IC (not shown) to produce the liquid crystal display device with built-in touch sensing function in each example.

The schematic structure of the liquid crystal display device with built-in touch sensing function, the surface resistance value [Ω/□] at the initial stage and after the wet-heat test, the wet-heat surface resistance change ratio, the surface resistance value [Ω/□] of the adhesive layer and the wet-heat conductivity change ratio F _HT (ΔC(B)/ΔC(A)), the touch sensitivity stability and the ESD evaluation results of each example are shown in Table 1. In addition, N,N-dimethylformamide and diethylene glycol dimethyl ether used in Comparative Examples 2 and 3 are not high-boiling point compounds, but are recorded in the high-boiling point compound column for convenience.

[Table 1] Table 1 Conductive layer Adhesive layer Conductive layer surface resistance [Ω/□] Wet-heat surface resistance change ratio Adhesive layer surface resistance [Ω/□] ΔC(B)/ΔC(A) Touch sensitivity stability ESD Composition Conductivity Stabilizer Composition Conductive agent Type Boiling point Dispensing amount Early days After wet heat test Embodiment 1 B1 Triethylene glycol 287℃ 3% C1 - 3.6E+07 4.2E+07 1.18 OVER 0.96 ◎ ○ Embodiment 2 B2 Diethylene glycol 244℃ 3% C1 - 6.9E+07 7.9E+07 1.14 OVER 0.96 ◎ ○ Embodiment 3 B3 Ophthalmic acid 246℃ 3% C1 - 2.3E+07 2.4E+07 1.02 OVER 0.99 ◎ ○ Embodiment 4 B4 Ophthalmic acid 246℃ 10% C1 - 2.3E+07 2.4E+07 1.02 OVER 0.99 ◎ ○ Embodiment 5 B5 glycerin 290℃ 3% C1 - 5.6E+07 8.1E+07 1.45 OVER 0.89 ◎ ○ Embodiment 6 B6 N-Methylpyrrolidone 204℃ 3% C1 - 2.0E+07 1.7E+06 0.08 OVER 1.58 ○ ○ Embodiment 7 B7 Dimethyl sulfoxide 189℃ 5% C1 - 4.0E+07 3.0E+06 0.08 OVER 1.70 ○ ○ Embodiment 8 B1 Triethylene glycol 287℃ 3% C2 LiTFSI 3.6E+07 4.2E+07 1.18 5.0E+09 0.96 ◎ ◎ Embodiment 9 B2 Diethylene glycol 244℃ 3% C2 LiTFSI 6.9E+07 7.9E+07 1.14 5.0E+09 0.96 ◎ ◎ Embodiment 10 B3 Ophthalmic acid 246℃ 3% C2 LiTFSI 2.3E+07 2.4E+07 1.02 5.0E+09 0.99 ◎ ◎ Embodiment 11 B4 Ophthalmic acid 246℃ 10% C2 LiTFSI 2.3E+07 2.4E+07 1.02 5.0E+09 0.99 ◎ ◎ Comparison Example 1 B8 - - - C1 - 2.2E+09 4.0E+06 0.0018 OVER 101.92 × ○ Comparison Example 2 B9 N,N-Dimethylformamide 153℃ 3% C1 - 6.3E+07 6.0E+05 0.01 OVER 2.44 × ○ Comparison Example 3 B10 Diethylene glycol dimethyl ether 162℃ 3% C1 - 7.0E+07 5.0E+05 0.01 OVER 2.59 × ○

As shown in Table 1, in Examples 1 to 11 in which a high boiling point compound having a boiling point of 180°C or more is used in the formation of the conductive layer, the wet-heat surface resistance change ratio of the conductive layer is within the range of 0.05 to 10, and the touch sensitivity stability evaluation results are all qualified. In these examples, the wet-heat conductivity change ratio F _HT is also less than 2. In addition, in Examples 1 to 5 and 8 to 11 in which a high boiling point compound having a boiling point of 210°C or more is used, the range of the wet-heat surface resistance change ratio of the conductive layer is narrower, and particularly excellent evaluation results are obtained. In addition, in Examples 1 to 11, the ESD evaluation results are also good, and Examples 8 to 11 in which the adhesive layer includes a conductive agent obtain particularly excellent results. In contrast, in Comparative Examples 1 to 3, which do not use a high boiling point compound having a boiling point of 180°C or more, the wet-heat surface resistance change ratio of the conductive layer is less than 0.05, and the touch sensitivity stability evaluation result is poor. In Comparative Examples 1 to 3, the wet-heat conductivity change ratio F _HT also exceeds 2. Based on the above results, it can be seen that in a liquid crystal display device with a built-in touch sensing function, by configuring a conductive layer on a visual side closer to the touch sensor portion, the wet-heat conductivity change ratio F _HT is less than 2, or the wet-heat surface resistance change ratio of the conductive layer is 0.05 to 10, and the conductive layer is formed using a conductive polymer and a high-boiling point compound with a boiling point of 180° C. or more. Even when exposed to a wet and hot environment, it is possible to prevent the generation of electrostatic unevenness and maintain a stable touch sensor sensitivity.

The specific examples of the present invention are described in detail above, but these are only examples and do not limit the scope of the patent application. The technology described in the scope of the patent application includes various changes and modifications to the specific examples described above.

1,2,3,4,5,6,7,8,9: LCD display device with built-in touch sensing function 101,102,103,104,105,106,107: In-cell LCD panel 110: Polarizing film with conductive layer 111: First polarizing film 112: First adhesive layer 113: Conductive layer 114: Surface treatment layer 120: Liquid crystal unit 125: Liquid crystal layer 130: Touch sensing electrode part (touch sensor part) 13 1: Detection electrode 132: Driving electrode 141: First transparent substrate 142: Second transparent substrate 150: Polarizing film with adhesive layer 151: Second polarizing film 152: Second adhesive layer 170: Conductive structure 171: Conductive structure 201: Semi-embedded LCD panel 202: Surface-embedded LCD panel 300: Evaluation kit 302: Touch panel 304: Cover glass S: Polarizing film sample with conductive layer T: Terminal

FIG. 1 is a cross-sectional view schematically showing the main part of an embedded liquid crystal display device in one embodiment. FIG. 2 is a cross-sectional view schematically showing the main part of an embedded liquid crystal display device in another embodiment. FIG. 3 is a cross-sectional view schematically showing the main part of an embedded liquid crystal display device in another embodiment. FIG. 4 is a cross-sectional view schematically showing the main part of an embedded liquid crystal display device in another embodiment. FIG. 5 is a cross-sectional view schematically showing the main part of an embedded liquid crystal display device in another embodiment. FIG. 6 is a cross-sectional view schematically showing the main part of an embedded liquid crystal display device in another embodiment. FIG. 7 is a cross-sectional view schematically showing the main part of an embedded liquid crystal display device in another embodiment. FIG. 8 is a cross-sectional view schematically showing the main part of a semi-embedded liquid crystal display device in one embodiment. FIG9 is a schematic cross-sectional view of a main part of a surface-mounted liquid crystal display device in an embodiment. FIG10 is a schematic diagram for explaining a method for measuring a difference between a current value of a touch panel and a base current value of a touch panel when a conductive layer is disposed on the touch panel. FIG11 is a diagram showing a correlation between ΔC (Cooked Data (Max-Min)) and a surface resistance value [Ω/□] of the conductive layer when a conductive layer is disposed.

1: LCD display device with built-in touch sensing function

101: Embedded LCD panel

110: Polarizing film with conductive layer

111: 1st polarizing film

112: 1st adhesive layer

113: Conductive layer

114: Surface treatment layer

120: Liquid crystal unit

125: Liquid crystal layer

130: Touch sensing electrode part (touch sensor part)

131: Detection electrode

132: Driving electrode

141: 1st transparent substrate

142: Second transparent substrate

150: Polarizing film with adhesive layer

151: Second polarizing film

152: Second adhesive layer

170: Conductive structure

171: Conductive structure

Claims (10)

A liquid crystal display device having a built-in touch sensing function and comprising the following components: a liquid crystal layer including liquid crystal molecules, a touch sensor portion, and first and second polarizing films respectively arranged on both sides of the liquid crystal layer, wherein the first polarizing film is arranged on the visual side of the liquid crystal layer and closer to the visual side than the touch sensor portion; wherein a conductive layer is arranged on the visual side closer to the touch sensor portion, wherein the wet-heat conductivity change ratio _FHT of the conductive layer expressed by formula (1) is less than 2, and _FHT =△C(B)/△C(A)‧‧‧‧‧(1)(In formula (1), △C(B) is the difference between the current value flowing in the touch panel and the base current value of the touch panel when the conductive layer after the wet heat test implemented at a temperature of 85°C and a relative humidity of 85% for 24 hours is arranged on the touch panel for evaluation; △C(A) is the difference between the current value flowing in the touch panel and the base current value of the touch panel when the conductive layer before the wet heat test is arranged on the touch panel for evaluation). A liquid crystal display device having a built-in touch sensing function and comprising the following components: a liquid crystal layer including liquid crystal molecules, a touch sensor portion, and first and second polarizing films respectively disposed on both sides of the liquid crystal layer, wherein the first polarizing film is disposed on the viewing side of the liquid crystal layer and closer to the viewing side than the touch sensor portion; and the second polarizing film is disposed on the viewing side of the liquid crystal layer and closer to the viewing side than the touch sensor portion. A conductive layer is arranged on the visual side, and the wet-heat surface resistance change ratio S/P of the conductive layer meets the condition: 0.05≦S/P≦10, where S is the surface resistance value [Ω/□] of the conductive layer after the wet-heat test at a temperature of 85°C, a relative humidity of 85% and 24 hours, and P is the surface resistance value [Ω/□] of the conductive layer before the wet-heat test. A liquid crystal display device having a built-in touch sensing function and having the following components: a liquid crystal layer including liquid crystal molecules, a touch sensor portion, and first and second polarizing films respectively arranged on both sides of the liquid crystal layer, wherein the first polarizing film is arranged on the visual side of the liquid crystal layer and closer to the visual side than the touch sensor portion; wherein a conductive layer is arranged on the visual side closer to the touch sensor portion, and the conductive layer is formed of a conductive composition including a conductive polymer and a high boiling point compound having a boiling point of 180°C or more. For a liquid crystal display device as claimed in claim 1 or 3, the wet-heat surface resistance change ratio S/P of the conductive layer satisfies the condition: 0.05≦S/P≦10, where S is the surface resistance value [Ω/□] of the conductive layer after a wet-heat test at a temperature of 85°C, a relative humidity of 85% and for 24 hours, and P is the surface resistance value [Ω/□] of the conductive layer before the wet-heat test. As in claim 3, the liquid crystal display device, wherein the content of the high boiling point compound in the conductive composition is 0.1-10% by weight. As in claim 3 or 5, the liquid crystal display device, wherein the boiling point of the high boiling point compound is 210~290℃. A liquid crystal display device as claimed in claim 3 or 5, wherein the high boiling point compound is a glycol ether solvent. A liquid crystal display device as claimed in any one of claims 1, 2, 3, and 5, wherein the conductive layer comprises a thiophene polymer as a conductive polymer. A liquid crystal display device as claimed in any one of claims 1, 2, 3, and 5, wherein the conductive layer contains an adhesive. A manufacturing method is a manufacturing method of a liquid crystal display device with a built-in touch sensing function having the following components: a liquid crystal layer including liquid crystal molecules, a touch sensor portion, and first and second polarizing films respectively arranged on both sides of the liquid crystal layer, wherein the first polarizing film is arranged on the visual side of the liquid crystal layer and closer to the visual side than the touch sensor portion; the manufacturing method includes the step of arranging a conductive layer closer to the visual side than the touch sensor portion; the conductive layer is formed by a conductive composition including a conductive polymer and a high boiling point compound having a boiling point of 180°C or above.