TWI628265B - Liquid crystal display panel and manufacturing method thereof - Google Patents

Abstract

A liquid crystal display panel and a manufacturing method thereof. The liquid crystal composition of the liquid crystal display panel has 0 <K33 / K11 ≦ 1.05, 0 <K33 ≦ 14 piconewtons (pN), and 0 <γ1 ≦ 100mPa. s and other characteristics.

Description

Liquid crystal display panel and manufacturing method thereof

The present invention relates to a display device, and more particularly, to a liquid crystal display panel and a manufacturing method thereof.

Polymer Stabilized Vertical Alignment (PSVA) liquid crystal displays have the advantage of high contrast, and are currently widely used in mass production in the industry. As the display response rate requirements continue to increase, the development of liquid crystal materials with fast response rates is a trend, and the response time of liquid crystals is related to their parameters, rotational viscosity coefficient and elastic coefficient. Generally, by reducing the rotational viscosity coefficient or increasing the elastic coefficient To achieve the purpose of rapid response. However, the increase of the liquid crystal elasticity coefficient will also increase the liquid crystal's sensitivity to temperature. As the ambient temperature rises, the liquid crystal generates a voltage-transmittance shift (VT shift) phenomenon at a low gray level (the driving voltage is about 2 to 3 volts), which in turn causes the gamma of the liquid crystal display panel. (Gamma) change (that is, the brightness of the liquid crystal display panel will be changed), under the condition that the temperature uniformity of the backlight module is not good, the brightness uniformity of the liquid crystal display panel will be poor.

The invention provides a liquid crystal display panel and a manufacturing method thereof, which can improve the liquid crystal response rate and improve the problem of poor brightness uniformity of the liquid crystal display panel.

A liquid crystal display panel of the present invention includes a first substrate, a second substrate, and a liquid crystal layer. The liquid crystal layer is disposed between the first substrate and the second substrate. The liquid crystal layer includes a liquid crystal composition. The liquid crystal composition has 0 <K33 / K11 ≦ 1.05, 0 <K33 ≦ 14 piconewtons (pN), and 0 <γ1 ≦ 100mPa. ． s and other characteristics, where K33 is the bend elastic constant of the liquid crystal composition, K11 is the splay elastic constant of the liquid crystal composition, and γ1 is the rotational viscosity coefficient of the liquid crystal composition.

In an embodiment of the present invention, the liquid crystal display panel further includes a first electrode and a second electrode. The first electrode is disposed on the first substrate. The second electrode is disposed on the second substrate. The material of the first electrode and the second electrode includes indium tin oxide or indium zinc oxide.

In an embodiment of the present invention, the liquid crystal display panel further includes a first alignment layer and a second alignment layer, wherein the first alignment layer is disposed on the first electrode and the second alignment layer is disposed on the second electrode.

The liquid crystal display panel of the present invention includes a first substrate, a second substrate, and a liquid crystal layer. The liquid crystal layer is disposed between the first substrate and the second substrate. The liquid crystal layer includes a liquid crystal composition. The retardation value of the liquid crystal composition is greater than 0 nm and 340nm or less.

The method for manufacturing a liquid crystal display panel of the present invention includes the following steps. A first substrate and a second substrate are provided, wherein a liquid crystal layer is provided between the first substrate and the second substrate. A liquid crystal composition is added to the liquid crystal layer, and the liquid crystal composition has 0 <K33 / K11 ≦ 1.05, 0 <K33 ≦ 14 piconewtons (pN), 0 <γ1 ≦ 100mPa. s and other characteristics, where K33 is the bend elastic constant, K11 is the splay elastic constant, and γ1 is the rotational viscosity coefficient of the liquid crystal composition.

In one embodiment of the present invention, the retardation value of the liquid crystal composition is greater than 0 nm and less than or equal to 340 nm.

In an embodiment of the present invention, the first substrate is a color filter substrate, and the second substrate to be matched is an active device array substrate.

In an embodiment of the present invention, the first substrate is a black matrix substrate, and the second substrate to be matched is an active element array substrate including a color filter.

In an embodiment of the present invention, the first substrate is a transparent substrate, and the second substrate to be matched is an active device array substrate including a color filter.

In an embodiment of the present invention, the method for manufacturing a liquid crystal display panel further includes forming a first electrode and a second electrode on the first substrate and the second substrate, respectively.

In an embodiment of the present invention, the method for manufacturing a liquid crystal display panel further includes forming a first alignment layer and a second alignment layer on the first electrode and the second electrode, respectively.

Based on the above, the present invention improves the response rate of the liquid crystal by using a liquid crystal composition with specific characteristics, and at the same time improves the problem of poor brightness uniformity of the liquid crystal display panel, wherein the liquid crystal composition has 0 <K33 / K11 ≦ 1.05, 0 < K33 ≦ 14 piconewtons (pN) and 0 <γ1 ≦ 100mPa. The characteristics of s, K33 is the bend elastic constant of the liquid crystal composition, K11 is the splay elastic constant of the liquid crystal composition, and γ1 is the rotational viscosity coefficient of the liquid crystal composition. In addition, in some embodiments, the liquid crystal group The compound has a characteristic that the retardation value is greater than 0 nm and less than or equal to 340 nm, and the sensitivity of the transmittance of the liquid crystal composition to temperature changes can be further reduced.

In order to make the above features and advantages of the present invention more comprehensible, embodiments are hereinafter described in detail with reference to the accompanying drawings.

102, 104‧‧‧ substrate

106, 108‧‧‧ electrodes

110, 112‧‧‧Alignment layer

114‧‧‧LCD layer

202‧‧‧Display Panel

P1 ~ P15‧‧‧Designated location

S302 ~ S308, S402‧‧‧Manufacturing method of liquid crystal display panel

FIG. 1 is a schematic diagram of a liquid crystal display panel according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of a liquid crystal display panel according to another embodiment of the present invention.

FIG. 3 is a schematic flowchart of a method for manufacturing a liquid crystal display panel according to an embodiment of the present invention.

FIG. 4 is a schematic flowchart of a method for manufacturing a liquid crystal display panel according to another embodiment of the present invention.

FIG. 1 is a schematic diagram of a liquid crystal display panel according to an embodiment of the present invention. Please refer to FIG. 1. The liquid crystal display panel may be, for example, a polymer-maintained vertical alignment type liquid crystal display panel including a substrate 102, a substrate 104, and a liquid crystal layer 114. In addition, the liquid crystal display panel may further include an electrode 106, an electrode 108, an alignment layer 110, and an alignment layer 112. The electrode 106 is disposed on the substrate 102, and the electrode 108 is disposed on the substrate 104. In addition, the alignment layer 110 is disposed on the electrode 106, the alignment layer 112 is disposed on the electrode 108, and the liquid crystal layer 114 is disposed on the alignment layer 110 and the alignment layer 112. between. Of which substrate 102 It may be, for example, a color filter substrate, and the substrate 104 may be, for example, an active device array substrate. In other embodiments, the substrate 102 may be, for example, a black matrix substrate or a transparent substrate, and the substrate 104 may, for example, include a color filter Active element array substrate. In addition, the material of the electrodes 106 and 108 may include, for example, indium tin oxide or indium zinc oxide, and the alignment layer 110 and the alignment layer 112 may include, for example, a material of polyimide.

The liquid crystal layer 114 includes a liquid crystal composition. The liquid crystal composition may be, for example, a negative type liquid crystal, but is not limited thereto. The dielectric anisotropy is less than 0, and the composition is not particularly limited. However, the liquid crystal composition must have 0 <K33. /K11≦1.05, 0 <K33 ≦ 14 piconewtons (pN), 0 <γ1 ≦ 100mPa. s and other characteristics, where K33 is the bend elastic constant of the liquid crystal composition, K11 is the splay elastic constant of the liquid crystal composition, and γ1 is the rotational viscosity coefficient of the liquid crystal composition. When K33 and K11 increase, the Shortening the response time of the liquid crystal composition, and increasing the rotational viscosity coefficient γ1 will make the response time of the liquid crystal composition longer.

Further, the liquid crystal composition may contain, for example, at least one compound selected from the group of compounds represented by the formula (1) as a first component described below, and a second component selected from the group represented by the formula (2). A group of compounds represented by at least one compound.

In formula (1), Y1 and Y2 are each independently -CH = CH2 (vinyl), -CH = CHCH3, -CH = CHF, -CH = CF2, an alkyl group having 1 to 6 carbon atoms, For example, propyl, hexyl, alkoxy having 1 to 6 carbon atoms, such as ethoxyl (ethoxy) or methoxyl (methoxy); ring A and ring B are each independently 1,4- Cyclohexyl or 1,4-phenyl; m and n are each independently an integer of 0 to 3, and m + n ≧ 2.

In the formula (2), Y3 is an alkyl group having 1 to 6 carbon atoms, such as -CH3 (methyl), -C2H5 (ethyl), -C3H7 (propyl), -C4H9 (butyl), -C5H11 ( Pentyl) or -C6H12 (hexyl); Y4 is an alkoxy group having 1 to 4 carbons or an alkyl group having 1 to 4 carbons, such as -OCH3 (methoxy), -OC2H5 (ethoxy), -OC3H7 (propoxy), -OC4H9 (butoxy), -CH3 (methyl), -C2H5 (ethyl), -C3H7 (propyl), or -C4H9 (butyl); Z is a single bond,- C2H4-, -COO-, -OCO-, or -CH = CH-; Ring C and Ring D are each independently 1,4-cyclohexyl or 1,4-phenylene; R is F (fluoro), Cl ( (Chloro), Br (bromine), CF3 (trifluoromethyl) or CN (cyano); p and q are each independently an integer of 0 to 3, p + q ≧ 1, and r is an integer of 0 to 4, when r When ≧ 2, each of R may be the same or different.

By adjusting the characteristics of the liquid crystal composition as above, the response rate of the liquid crystal can be increased, and at the same time the problem of poor uniformity of the brightness of the liquid crystal display panel can be improved. For example, Table 1 shows the characteristics of the conventional liquid crystal composition and the liquid crystal composition. For the comparison table of the transmittance and voltage-transmittance shift (VT shift) of sample A and sample B, please refer to Table 1.

As shown in Table 1, the conventional liquid crystal composition has the same threshold voltage as the sample A, and the sample B has a larger threshold voltage. The threshold voltage is a voltage that causes the liquid crystal molecules to start to rotate. The value of the voltage applied to the liquid crystal composition when the transmittance of the object is 10%. The K33 value of Sample A and Sample B are both less than 14 and the ratio of K33 / K11 is less than 1.05, while the K33 value of the conventional liquid crystal composition is greater than 14 and the ratio of K33 / K11 is greater than 1.05. In addition, the retardation values of the conventional liquid crystal composition and the samples A and B are almost the same. It can be seen from the experimental results that under the same starting voltage and the same bias voltage (the bias voltage of this embodiment is 2.5 volts), both sample A and sample B have lower voltage-through Transmittance shift. The voltage-transmittance shift is calculated by first subtracting the transmittance corresponding to the liquid crystal composition at high temperature (65 ° C) and subtracting the corresponding transmittance of the liquid crystal composition at low temperature (25 ° C) to obtain a The difference is divided by the transmittance corresponding to the liquid crystal composition at a low temperature (25 ° C.) to obtain a voltage-transmittance shift percentage value. In the example of Table 1, the voltage-transmittance shift percentages of sample A and sample B are smaller than the traditional liquid crystal composition, that is, the temperature of sample A and sample B rises from low temperature (25 ° C) to high temperature under the same bias voltage. The percentage change in transmittance corresponding to (65 ° C) is smaller than that of the conventional liquid crystal composition. Sample A and sample B have the advantage that the transmittance is less sensitive to temperature changes than the conventional liquid crystal composition.

In addition, the measurement method of the maximum brightness difference and the central transmittance in Table 1 may be, for example, measuring 15 positions P1 to P15 specified on the display panel 202 shown in FIG. 2, where the maximum brightness difference is between The maximum value of the percentage difference of the brightness before and after the temperature rises at the 15 positions P1 to P15 of the display panel, the central transmittance is the transmittance at the central position P8 of the display panel, and the response time Toff is a certain value for the liquid crystal composition. After the voltage is released, the time required for the liquid crystal to return to positioning from a certain angle of rotation. When the temperature of the display panel rises and stabilizes, the left and right positions (that is, positions P1 to P6, P10 to P15) will have higher temperatures, while the center position (that is, positions P7 to P9) will have lower temperatures. temperature. It can be known from Table 1 that under the same temperature environment, the maximum brightness change of sample A and sample B before and after the display panel is heated are lower than the maximum brightness change of the traditional liquid crystal composition, that is, sample A and sample B have lower brightness. The amount of change. In addition, comparing the center transmittance of the display panel of the sample A with the conventional liquid crystal composition, it can be seen that, even at the same threshold voltage, the elastic coefficient of the sample A is reduced. For K11 and K33, as long as the K33 / K11 ratio of Sample A is lower than 1.05, Sample A can also maintain the same level of central transmittance as the conventional liquid crystal composition. In addition, when the critical voltage of the liquid crystal composition is increased (such as sample B), it can also maintain the same level of central transmittance.

In addition, in some embodiments, the retardation value of the liquid crystal composition can also be set to be greater than 0 nm and less than or equal to 340 nm. This can further reduce the sensitivity of the liquid crystal composition's transmittance to temperature changes, thereby improving the liquid crystal. The purpose of response rate, and at the same time improve the problem of poor brightness uniformity of the liquid crystal display panel. For example, Table 2 is a comparison table of the transmittance and voltage-transmittance shift (V-T shift) of the conventional liquid crystal composition and Sample C and Sample D. Please refer to Table 2.

In the example in Table 2, the K33 value of sample C is less than 14 and the ratio of K33 / K11 is less than 1.05, and the ratio of K33 / K11 of sample D is greater than 1.05, and its The K33 value is greater than 14, and the retardation values of Sample C and Sample D are both less than 340 nm. It can be seen from the experimental results that when the retardation value is less than 340 nm, the voltage-transmittance shift can be effectively reduced, and the sensitivity of the liquid crystal composition's transmittance to temperature changes is reduced. Among them, even if the ratio of K33 / K11 of sample D is greater than 1.05 and the value of K33 is greater than 14, the voltage-permeability shift can be reduced. However, from the experimental data of sample C and sample D in Table 2, it can be seen that when the ratio of K33 / K11 is greater than When the value of 1.05 and K33 is greater than 14, the voltage-transmittance shift will obviously increase, but it is still lower than the voltage-transmittance shift of the conventional liquid crystal composition.

FIG. 3 is a schematic flowchart of a method for manufacturing a liquid crystal display panel according to an embodiment of the present invention. Referring to FIG. 3, a method for manufacturing a liquid crystal display panel according to an embodiment of the present invention includes the following steps. First, a first substrate and a second substrate are provided (step S302), wherein the first substrate is a color filter substrate or a black matrix substrate or a transparent substrate, and the second substrate is an active element array substrate or an active device including a color filter. Element array substrate. Then, a first electrode and a second electrode are formed on the first substrate and the second substrate, respectively (step S304). Next, a first alignment layer and a second alignment layer are formed on the first electrode and the second electrode, respectively (step S306). Then, a liquid crystal composition is added to the liquid crystal layer between the first substrate and the second substrate, wherein the liquid crystal composition has 0 <K33 / K11 ≦ 1.05, 0 <K33 ≦ 14 piconewtons (pN), 0 <γ1 ≦ 100mPa ． characteristics such as s (step S308), K33 is a bend elastic constant, K11 is a splay elastic constant, and γ1 is a rotational viscosity coefficient of the liquid crystal composition.

FIG. 4 is a schematic flowchart of a method for manufacturing a liquid crystal display panel according to another embodiment of the present invention. Please refer to FIG. 4. Differences between this embodiment and the embodiment of FIG. 3 In step S402 of this embodiment, the liquid crystal composition further includes a characteristic that the retardation value is greater than 0 nm and less than or equal to 340 nm. This can further reduce the sensitivity of the liquid crystal composition's transmittance to temperature changes.

In summary, the embodiments of the present invention improve the liquid crystal response rate by using a liquid crystal composition with specific characteristics, and at the same time improve the problem of poor uniformity of the brightness of the liquid crystal display panel. The liquid crystal composition has 0 <K33 / K11 ≦ 1.05, 0 <K33 ≦ 14 piconewtons (pN) and 0 <γ1 ≦ 100mPa. The characteristics of s, K33 is the bend elastic constant of the liquid crystal composition, K11 is the splay elastic constant of the liquid crystal composition, and γ1 is the rotational viscosity coefficient of the liquid crystal composition. In some embodiments, the liquid crystal composition can further have a characteristic that the retardation value is greater than 0 nm and less than or equal to 340 nm, so as to further reduce the sensitivity of the liquid crystal composition's transmittance to temperature changes.

Claims (7)

A liquid crystal display panel includes: a first substrate; a second substrate; and a liquid crystal layer disposed between the first substrate and the second substrate, and including a liquid crystal composition. The liquid crystal composition has the following characteristics: 0 <K33 / K11 ≦ 1.05, 0 <K33 ≦ 14 piconewtons, 0 <γ1 ≦ 100mPa. s where K33 is the bending elastic constant of the liquid crystal composition, K11 is the stretch elastic constant of the liquid crystal composition and γ1 is the rotational viscosity coefficient of the liquid crystal composition, and the retardation value of the liquid crystal composition is greater than 0 nm and less than or equal to 340nm. The liquid crystal display panel according to item 1 of the scope of patent application, wherein the first substrate is a color filter substrate or a black matrix substrate or a transparent substrate, and the second substrate is an active element array substrate or a substrate including a color filter. Active element array substrate. The liquid crystal display panel according to item 1 of the scope of patent application, further comprising: a first electrode disposed on the first substrate; and a second electrode disposed on the second substrate, wherein the first electrode and The material of the second electrode includes indium tin oxide or indium zinc oxide. The liquid crystal display panel according to item 3 of the scope of patent application, further comprising: a first alignment layer disposed on the first electrode; and a second alignment layer disposed on the second electrode. A method for manufacturing a liquid crystal display panel includes: providing a first substrate and a second substrate, wherein a liquid crystal layer is provided between the first substrate and the second substrate; and adding a liquid crystal composition to the liquid crystal layer, The liquid crystal composition has the following characteristics: 0 <K33 / K11 ≦ 1.05, 0 <K33 ≦ 14 piconewtons (pN), 0 <γ1 ≦ 100mPa. s where K33 is the bend elastic constant, K11 is the splay elastic constant, γ1 is the rotational viscosity coefficient of the liquid crystal composition, and the retardation value of the liquid crystal composition is greater than 0 nm and less than or equal to 340 nm. The method for manufacturing a liquid crystal display panel according to item 5 of the scope of patent application, wherein the first substrate is a color filter substrate or a black matrix substrate or a transparent substrate, and the second substrate is an active element array substrate or includes a color filter. Active element array substrate for light sheet. The method for manufacturing a liquid crystal display panel according to item 5 of the scope of patent application, further comprising: forming a first electrode and a second electrode on the first substrate and the second substrate, respectively.