TWI818289B - Touch display module - Google Patents

Abstract

A touch display module includes a touch device and a polarizing element. The polarizing element includes a polarizer and a retardation film assembly. The retardation film assembly has a polarization ellipticity value (e-value), and the absolute value of the e-value is greater than 0.8. A reflection rate of the polarizing element is less than 6%, and a total reflection rate of the touch device and the polarizing element is less than 7%.

Description

Touch display module

This disclosure relates to touch display modules.

Organic light-emitting diode displays have the advantages of low power consumption, high color brightness and high contrast, which can give people better visual enjoyment. However, the biggest challenge is how to effectively resist the reflected light generated by incident light from the external environment. Reduce display troubles. One solution is to install a circular polarizer as an anti-reflective film to reduce the amount of ambient light that is reflected back after it enters the display. The theoretical principle of a circular polarizer that combines a quarter wave plate (QWP) and a linear polarizer is to circularly polarize the external ambient light incident on the display, and the incident circularly polarized light (ex. left-handed light) will pass through the display. After reflection by the electrode, it is reversed into circularly polarized light in the opposite direction of rotation (ex. right-handed light), and the circularly polarized light in the opposite direction of rotation (right-handed light) passes through the quarter-wave plate again and becomes the polarization direction positive to the linear polarizer. The intersection of linear polarization and linear polarization causes the linear polarization orthogonal to the polarization direction of the linear polarizer to be unable to emit light from the linear polarizer, thereby eliminating or reducing reflections caused by external ambient light, thereby avoiding problems such as reflection interference or uneven brightness in the display screen. From the above principle, the circular polarization of external ambient light by the anti-reflective sheet is the first step of the above-mentioned anti-reflective mechanism, so it is one of the important factors in the anti-reflective effect. Generally speaking, for the same material, increasing the circular polarization conversion rate can lead to better anti-reflection effects.

For example, TWI580995B (TW'995) proposes an anti-ambient light reflection film, which includes: a linear polarizing layer and an optically active liquid crystal layer formed on the linear polarizing layer. Examples 1-4 from Table 2 of TW'995 show the circular polarization conversion When the rate is close to 1 (that is, linear polarization is fully converted into circular polarization), the lowest reflectivity of light is 7.62%. However, the present invention believes that the reflectivity of about 8% cannot meet the increasingly sophisticated display requirements, especially at present, high-resolution and high-quality videos such as 4K and 8K have been favored by users. On the other hand, the assembly of touch-sensitive electrodes on the display becomes a touch-sensitive display screen, which is one of the important human-machine interfaces in modern society, and the touch-sensitive electrodes are also factors that cause ambient light reflection. In summary, the reflectivity of the anti-ambient light reflection film proposed in TW’995 is too high, so it may not be able to meet high-end display requirements when used with displays and touch sensing electrodes. In other words, how to obtain an anti-reflective sheet with lower reflectivity is actually a major issue for those skilled in the art.

On the other hand, the circular polarization conversion rate of TW’995 Examples 1-4 is close to 1, which is equivalent to the ideal value. It is speculated that it should be laboratory-grade liquid crystal material, which is very expensive and is not conducive to commercial use. In fact, in the commercial market, due to cost considerations, the material specifications of electronic products are not so close to the ideal value. In other words, if the general commercial specifications/costs are taken into account, the circle of Examples 1-4 of TW'995 will be The polarization conversion rate is bound to decrease (for example, the circular polarization conversion rate drops to 0.9). It is conceivable that the aforementioned light reflectivity will also be increased as a result, making it even more difficult to meet the demand for low reflectivity.

Furthermore, the optically active liquid crystal layer used in TW'995 is a cholesteric liquid crystal. Its working principle is to stack multiple layers of liquid crystals with different axial directions to achieve circular polarization of light, as shown in Figure 2 of TW'995 shown, therefore. The multi-layer liquid crystal structure of TW’995 will cause the problem that the thickness of the anti-ambient light reflection film cannot be reduced, so it cannot meet the user’s demand for thin and light portable devices.

The touch display module according to the embodiment of the present disclosure can have a sufficiently low reflectivity to reduce the reflection of ambient light from the outside and avoid affecting the display quality.

The technical solution adopted in this disclosure is:

One aspect of this disclosure relates to a touch display module. According to one or more implementations of the present disclosure, a touch display module includes a touch element and a polarizing element. The polarizing element is arranged on the touch element. The polarizing element includes a linear polarizing plate and a phase retardation film assembly. When the linear polarized light generated by the ambient light passing through the linear polarizer is converted into circularly polarized light through the phase retardation film assembly, the ratio of linear polarization into circular polarization is defined as the circular polarization conversion rate of the phase retardation film assembly. In the wavelength range between 450nm and 650nm, the absolute value of the circular deflection conversion rate is greater than 0.8. In the wavelength range between 450nm and 650nm, the reflectance of ambient light through the polarizing element is less than 6%.

According to one or more embodiments of the present disclosure, the touch element includes a touch sensor composed of silver nanowires and/or polymer films. The touch sensor is located on the linear polarizing plate or the phase retardation film assembly.

In some embodiments, the combination of the touch element and the polarizing element has a total reflectivity in a wavelength range between 450 nm and 650 nm, and the total reflectance is less than 7% or less than 6%; or in a wavelength range of 450 nm to 650 nm , the refractive index change rate caused by the polarizing element before and after being combined with the touch element is between the range of 0% to 15%, the range of 0% to 13%, the range of 0% to 8%, or 0 % to 2%.

According to one or more embodiments of the present disclosure, the phase retardation film assembly is composed of a positive dispersion type half-wave plate and a positive dispersion type quarter-wave plate.

In some embodiments, the optical axis angle of the half-wave plate relative to the linear polarizer is in the range of 10 degrees to 15 degrees, and the optical axis angle of the quarter-wave plate relative to the linear polarizer is in the range of 65 degrees to 75 degrees. between the ranges.

According to one or more embodiments of the present disclosure, the phase retardation film assembly is composed of a reverse dispersion type quarter wave plate.

In some embodiments, the optical axis angle of the quarter wave plate relative to the linear polarizing plate is 45 degrees.

According to one or more embodiments of the present disclosure, the phase retardation film assembly includes a liquid crystal type phase retardation film or a polymer film type phase retardation film.

According to one or more embodiments of the present disclosure, an absolute value of the circular polarization conversion ratio is in a range of 0.8 to 0.95 in a wavelength range of 450 nm to 650 nm, where in a wavelength range of 450 nm to 650 nm Below, the reflectivity of ambient light passing through the polarizing element is less than 5.5%.

One of the disclosed aspects relates to a touch display module. According to one or more implementations of the present disclosure, a touch display module includes a touch element and a polarizing element. The polarizing element is arranged on the touch element. The polarizing element includes a linear polarizing plate and a phase retardation film assembly. When the linear polarized light generated by the ambient light passing through the linear polarizer is converted into circularly polarized light through the phase retardation film assembly, the ratio of linear polarization into circular polarization is defined as the circular polarization conversion rate of the phase retardation film assembly. At a wavelength of 550nm, the absolute value of the circular deflection conversion rate is greater than 0.9. At a wavelength of 550nm, the reflectance of ambient light passing through the polarizing element is less than 5%.

In this way, through the embodiments of the present invention, the circular polarization conversion rate of the polarizing element does not need to be close to the theoretical value, so that the touch display module can reduce the reflection of incident light from the external environment, thereby improving the visual and operating experience of the touch display module. Without excessively increasing product costs.

The above is only used to describe the problems to be solved by the present disclosure, the technical means to solve the problems, the effects thereof, etc. The specific details of the present disclosure will be introduced in detail in the embodiments and related drawings below.

A plurality of embodiments of the present disclosure will be disclosed below with drawings. For clarity of explanation, many practical details will be explained together in the following description. However, it should be understood that these practical details should not be used to limit the disclosure. That is to say, in the embodiments of the present disclosure, these practical details are not necessary. In addition, for the sake of simplifying the drawings, some commonly used structures and components will be illustrated in a simple schematic manner in the drawings.

For display devices, reflections from external ambient light will affect the user's visual experience. For users of touch display modules, the reflection of external ambient light will affect the operating experience. The external ambient light covers a very wide wavelength range, and the present disclosure is for anti-reflection optical preparation for the wavelength band that the human eye is more sensitive to (such as 450nm-650nm).

This disclosure is related to the touch display structure, which can reduce the reflection of external ambient light, thereby reducing the interference from the reflection of external ambient light on the visual and operating experience, and can maintain the overall thickness and thinness. The present disclosure does not require the polarization element in the touch display structure to reach or be close to the ideal circular polarization conversion rate (that is, the circular polarization conversion rate is equal to 1) to obtain an anti-reflective element with low reflectivity, so it has advantages in cost and product quality. Pretty fine balance.

Please refer to picture 1. Figure 1 is a schematic cross-sectional view of a touch display module 100 according to an embodiment of the present disclosure.

As shown in FIG. 1 , in an embodiment of the present disclosure, a touch display module 100 at least includes an optical touch element 110 and a polarizing element 150 .

In this embodiment, the optical touch element 110 can be assembled with the display unit 120, for example, optical adhesive (OCA) is used to adhere and fix the two.

In some embodiments, the display unit 120 includes an organic light-emitting diode (OLED), a mini-LED display, or the like. Organic light-emitting diode displays can have the advantages of low power consumption, high color vividness and high contrast ratio. In some embodiments, one or more organic light-emitting diodes of the display unit 120 can form an active-matrix organic light-emitting diode (AMOLED) to display images and signals.

As shown in FIG. 1 , in one embodiment of the present disclosure, the display unit 120 can emit light L toward the direction D1 and display the image accordingly. That is to say, the user can receive the light L emitted by the display unit 120 along the direction D1 . signal.

In some implementations, the optical touch element 110 may include a touch sensor. The touch sensor can sense the user's touch and gestures, thus To realize the touch operation of the touch display module 100 .

In some embodiments of the present disclosure, the optical touch element 110 includes an electrode formed by patterning a transparent conductive layer or a transparent conductive film, which has high transmittance, such as visible light (such as a wavelength between 400 nm and 700 nm). ) has a light transmittance (Transmission) greater than about 88%, 90%, 91%, 92%, 93% or more. In some embodiments, the transparent conductive layer or transparent conductive film includes ITO material, silver nanowires (SNW) material, etc.

Please go back to picture 1. As shown in FIG. 1 , the polarizing element 150 is disposed on the optical touch element 110 . In some embodiments of the present disclosure, the polarizing element 150 can convert the ambient light from the external environment (such as the incident light L1) into polarized light, thereby reducing the reflection of the ambient light and then emitting along the direction D1 and affecting the user's viewing of the picture. Details See discussion below.

As shown in FIG. 1 , the polarizing element 150 may include a linear polarizing plate 160 and a phase retardation film assembly 170 . In this embodiment, the phase retardation film assembly 170 is located between the light exit surface of the optical touch element 110 and the polarizing plate 160 .

The linear polarizer 160 can be configured to convert the passing light into linearly polarized light. In some embodiments of the present disclosure, the degree of polarization (DOP) of the linear polarizer 160 is greater than 98%, but is not limited thereto.

In some embodiments, the phase retardation film assembly 170 may include one or more phase retardation films (Retarder). In this embodiment, the phase retardation film assembly 170 is composed of a positive dispersion type half-wave plate (Half-wave plate). It is composed of Wave Plate (HWQ) 173 and positive dispersion quarter wave plate (Quarter Wave Plate, QWP) 176. In this embodiment, the quarter wave plate 176 and the half wave plate 173 are both made of a single layer of liquid crystal coating, for example, a quarter wave plate made of a commercially available product: Reactive Mesogen (RM) reactive liquid crystal. One-wave plate 176 and one-half wave plate 173 (for example, manufacturer DNP; DNP_HWP and DNP_QWP).

In this way, the phase retardation film assembly 170 can be considered as a liquid crystal coating type phase retardation element. Since the thickness of the coating type liquid crystal is only a few microns (um), the overall thickness can be reduced. Compared with the thickness of the multi-layer cholesteric liquid crystal used in TW’995, the RM reactive liquid crystal used in this embodiment only needs to be coated with one layer to achieve the phase effect of delayed light, so it can meet the demand for thin products.

Please refer to Figure 2. When the external ambient light L1 is incident, the light is incident along the direction D2 which is opposite to the direction D1 (ie, the screen display direction), and the external ambient light is converted into linearly polarized light L2 by the linear polarizer 160. The linearly polarized light L2 then passes through the half-wave plate 173 and the quarter-wave plate 176 and is converted into circularly polarized light L3 (for example, left-handed light). When the circularly polarized light L3 is reflected by the optical touch element 110 or the display unit 120, reverse circularly polarized light L3' (for example, right-handed light) will be formed. At this time, the reverse circularly polarized light L3' then passes through the phase retardation film assembly 170 to form linearly polarized light L2' perpendicular to the optical axis of the linearly polarizing plate 160. Since the polarization angles are orthogonal, the linearly polarized light L2' cannot pass through the phase retardation film assembly 170. The linear polarizing plate 160 emits outward, that is, in an ideal state, no reflected light L1' is generated. As a result, the polarizing element 150 is optically called a circular polarizer (CPOL), which can In optical applications, it eliminates or reduces reflected light, so it is also called an anti-reflective element.

In short, through the arrangement of the polarizing element 150 , the external ambient light is converted into circularly polarized light, and then after the circularly polarized light is reflected again, the reflected circularly polarized light will be blocked by the linear polarizing plate 160 due to the polarization angle. In this way, external ambient light reflection can be prevented from affecting the visual effect of the touch display module 100 . It is worth mentioning that the polarizing element 150 can convert linearly polarized light into ideally completely circularly polarized light or elliptically polarized light that is close to circularly polarized light. In this way, the circular polarization conversion rate or circular polarization conversion rate (polarization ellipticity value, e-value for short) of the phase retardation film assembly 170 can be defined based on the ratio of linearly polarized light L2 into circularly polarized light. Since The circular deviation conversion rate has a positive/negative numerical value depending on the left-handed or right-handed rotation. For convenience of explanation, the circular deviation conversion rate of the present invention will be explained in terms of absolute values.

For example, when the circularly polarized light L3 is right-handed circularly polarized light, the circular polarization conversion rate of the phase retardation film assembly 170 is +1 (that is, completely converted); when the circularly polarized light L3 is right-handed elliptically polarized light, That is, a combination of a part of linearly polarized light and a part of circularly polarized light, then the circular polarization conversion rate of the phase retardation film assembly 170 is between +1 and 0; similarly, when the circularly polarized light L3 is left-handed circularly polarized light, the phase The circular deflection conversion rate of the retardation film assembly 170 is between -1 and 0. In general, when linearly polarized light is completely converted into circularly polarized light, the absolute value of the circularly polarized conversion rate is equal to 1.

In some embodiments, the absolute value of the circular deflection conversion ratio of the phase retardation film assembly 170 is less than 1. In other words, it does not need to be close to complete circular deflection. , it can still provide anti-reflective effect. Specifically, in some embodiments, in the wavelength range of 450-650 nm, as long as the absolute value of the circular polarization conversion rate of the phase retardation film assembly 170 is greater than 0.8 (it does not need to be close to the ideal value), the touch display can still be effectively reduced. The overall reflectivity of the module 100, for example, the reflectivity is less than 6% or less than 5.5%.

To further illustrate, when the absolute value of the circular deflection conversion rate of the phase retardation film assembly 170 is greater than 0.8 but does not need to be close to the ideal value, the effect of reducing the overall reflectivity of the touch display module 100 can still be obtained.

FIG. 3 shows a schematic diagram of the angles θ1 and θ2 between the optical axes of a polarizing element 150 according to an embodiment of the present disclosure. In FIG. 3 , the optical axis a1 corresponds to the linearly polarizing plate 160 . For the polarizing element 150 , the optical axis a2 corresponds to the half-wave plate 173 of the positive dispersion liquid crystal coating type, and the optical axis a3 corresponds to the quarter-wave plate 176 of the positive dispersion liquid crystal coating type. Since the half-wave plate 173 of the positive dispersion liquid crystal coating type and the quarter-wave plate 176 of the positive dispersion liquid crystal coating type are liquid crystal coating types, they only have single optical axes a2 and a3 respectively. a2 and a3 can be slow axes.

Relative to the optical axis a1 of the linear polarizing plate 160 , the optical axis a2 has an included angle θ1 between the optical axes. Relative to the optical axis a1 of the linear polarizing plate 160 , the optical axis a3 has an included angle θ2 between the optical axes. In some embodiments, the angle between the optical axes θ1 and θ2 may range from 0 degrees to 180 degrees. In this embodiment, the included angle θ1 of the optical axes is 15 degrees, and the included angle θ2 of the optical axes is 75 degrees, but it is not limited to this. In one embodiment, the optical axis angle θ1 is between 10 and 15 degrees, and the optical axis angle θ2 is between 65 and 75 degrees, but is not limited thereto.

Please return to Figure 2. According to an embodiment of the present disclosure, an incident light L1 is shown to enter a polarizing element 150 and then pass through the reflective surface 300, such as a semi-reflective mirror with a reflectivity of about 50-60% (manufacturer: 3D Lens). A schematic diagram of the reflected light L1' that passes through the polarizing element 150. FIG. 4 is a relationship diagram between the absolute value of the circular polarization conversion rate (e value) and the reflectance (R%) of the polarizing element 150 measured according to the above embodiment.

As shown in Figure 4 and Table 1 below, corresponding to the incident light L1 with an incident wavelength in the range of 450 nm to 650 nm, the absolute values of the circular polarization conversion rate (e value) of the polarizing element 150 of the present disclosure are all above 0.8, as shown by the dotted line ; And for incident light L1 in the range of 450nm to 650nm, the reflectance (R%) is less than 6%, or less than 5.5%.

In this way, when the corresponding incident wavelength is in the range of 450nm to 650nm Regarding the incident light L1, the absolute values of the circular polarization conversion ratio (e value) of the polarizing element 150 of this embodiment are all above 0.8, so that the reflectance in the range of 450nm to 650nm, which the human eye is sensitive to, is less than 6%, or less than 5.5%. . More specifically, when the incident light L1 corresponds to the incident wavelength in the range of 450 nm to 650 nm, the absolute value of the circular polarization conversion rate (e value) of the polarizing element 150 of this embodiment only needs to be between 0.82 and 0.92 and does not need to be close to the theoretical value. value (e value=1), it can make the reflectivity in the range of 450nm to 650nm, which the human eye is sensitive to, less than 6%, or less than 5.5%, so it has an advantage in commercial/industrial production costs. In one embodiment, the absolute value of the circular polarization conversion rate (e value) of the polarizing element 150 only needs to be between 0.8 and 0.95 and does not need to be close to the theoretical value (e value=1), so that the human eye can be sensitive to The reflectance in the range of 450nm to 650nm is less than 6%, or less than 5.5%.

More specifically, when the incident light L1 corresponds to the incident wavelength of 550 nm, the absolute value of the circular polarization conversion rate (e value) of the polarizing element 150 of this embodiment only needs to be 0.9 or above and does not need to be close to the theoretical value (e value= 1), it can make the reflectivity at 550nm, which the human eye is sensitive to, less than 6%, or less than 5.5%, or less than 5%. More specifically, when the incident light L1 corresponds to the incident wavelength of 550 nm, the absolute value of the circular polarization conversion rate (e value) of the polarizing element 150 of this embodiment only needs to be 0.9 or above and does not need to be close to the theoretical value (e value). =1), it can achieve a reflectivity of 4.9% at 550nm, which the human eye is sensitive to, so it has an advantage in commercial/industrial production costs. To sum up, the absolute value of the circular polarization conversion rate (e value) of the polarizing element 150 of this embodiment only needs to be between 0.9 and 0.95. Close to the theoretical value (e value=1), the reflectivity at 550nm, which the human eye is sensitive to, can be between 4.5~5.0%.

Figure 5 shows a graph showing the relationship between the absolute value of the circular deflection conversion rate (e value) and the reflectivity. Under an incident light in the range of 450nm to 650nm, the horizontal axis is the liquid crystal coating type phase retardation film assembly configured to use the circular deflection conversion rate (e value) of different absolute values of the present disclosure, and the vertical axis is the use of the corresponding phase The reflectance (R%) of the polarizing element of the retardation film assembly. It can be seen that once the absolute value of the circular polarization conversion rate (e value) is less than 0.8, it can be ensured that when the wavelength of the incident light is in the range of 450nm to 650nm, the reflectance (R%) of the polarizing element is less than 6%; and when the second The angle between the slow axis of the quarter wave plate 173 and the optical axis a1 of the linear polarizing plate 160 exceeds 15 degrees, or the angle between the slow axis of the quarter wave plate 176 and the optical axis a1 of the linear polarizing plate 160 exceeds 75 degrees. It may cause the absolute value of the circular deflection conversion rate (e value) to be less than 0.8, and result in a comparative example where the reflectance (R%) is greater than 6% in the wavelength range of 450nm to 650nm (such as data points a, b, c in Figure 5 ,d). The other data points in Figure 5 all meet the aforementioned embodiments and will not be described again here.

According to an embodiment of the present disclosure, after the optical touch element 110 is assembled into the aforementioned polarizing element 150, a test is performed to measure the circular polarization conversion rate and light reflectance in the wavelength range of 450 nm to 650 nm. In one embodiment, the combination of the optical touch element 110 and the polarizing element 150 can be regarded as an optoelectronic element, that is, an integrated element with both optical and electrical functions. The electrical function here refers to the touch sensing function, and the aforementioned The optoelectronic element has an overall reflectivity. Since the optical touch element 110 will also cause light reflection, the overall reflectivity of this type of optoelectronic element will be slightly greater than that of the polarizing element 150. In the product The overall reflectivity must also be small enough not to affect display quality. For the testing method in this embodiment, reference can be made to the method shown in Figure 2 and the foregoing related descriptions, and will not be described again here.

In one embodiment, the optical touch element 110 at least includes a touch electrode composed of silver nanowires and/or a polymer film. For specific methods, reference can be made to US20190227650A, CN101292362, etc., which are incorporated in their entirety. As shown in Figure 6, in the range of 450nm to 650nm that the human eye is sensitive to, the overall reflectance of the optical touch element 110 and the polarizing element 150 can be less than 7%, as shown in Table 2 below.

As shown in the table above, the corresponding incident wavelength is between 450nm and 650nm. In the range of incident light L1, the reflectivity of the optoelectronic element of this embodiment in the range of 450 nm to 650 nm, which the human eye is sensitive to, is less than 7% or less than 6%. In summary, the reflectivity of the optoelectronic element according to the embodiment of the present invention is between 5% and 6% in the range of 450nm to 650nm, which the human eye is sensitive to.

More specifically, when the incident light L1 corresponds to the incident wavelength of 550 nm, the reflectance of the photoelectric element at 550 nm of this embodiment is less than 6%, or less than 5.5%. More specifically, when the incident light L1 corresponds to the incident wavelength of 550 nm, the reflectance of the photoelectric element of this embodiment at the wavelength of 550 nm is 5.3%. In summary, the reflectivity of the optoelectronic element according to the embodiment of the present invention at a wavelength of 550 nm is between 5.0% and 5.5%.

In addition, when two components with different functions are combined, it often happens that the characteristics of each other will affect each other. According to embodiments of the present invention, it can be found that the characteristics of the polarizing element 150 will not be excessively degraded when a touch electrode composed of silver nanowires and/or a polymer film is combined with the polarizing element 150 . Specifically, when the touch electrode composed of nanosilver wires and/or polymer films in the embodiment of the present invention is combined with the aforementioned polarizing element 150, compared with the aforementioned polarizing element 150, when the wavelength is in the range of 450 nm to 650 nm, its The reflectivity change rate is below 15%; generally speaking, the reflectance change rate of the optoelectronic element according to the embodiment of the present invention is in the wavelength range of 450nm to 650nm in the range of 0%~15%, 0%~13%, and 0%~8 % or 0%~2%.

More specifically, at the corresponding wavelength of 550nm, the reflectance change rate is below 10%; still more specifically, at the corresponding wavelength of 550nm, the reflectance change rate is 8%. To sum up, when the wavelength of the optoelectronic element according to the embodiment of the present invention is 550nm, its reflectivity change rate is between 0% and 10%. 5%~10% or 5%~8%.

In some embodiments, a transparent protective cover can be further provided on the polarizing element 150 .

FIG. 7 illustrates a schematic cross-sectional view of a touch display module 200 according to an embodiment of the present disclosure.

In this embodiment, as shown in FIG. 7 , the touch display module 200 includes an optical touch element 210 , a display unit 220 and a polarizing element 250 . The polarizing element 250 includes a polarizing plate 260 and a liquid crystal coating type phase retardation film. Total 270.

The difference from the previous embodiment is at least that the phase retardation film assembly 270 may include a phase retardation film (Retarder). In this embodiment, the phase retardation film assembly 270 is composed only of the reverse dispersion type quarter wave plate 276 . In this embodiment, the quarter-wave plate 276 is a single-layer liquid crystal coating, for example, the quarter-wave plate 276 is made of a commercially available product: Reactive Mesogen (RM) reactive liquid crystal (manufacturer DNP; DNP_QWP). In this embodiment, the quarter-wave plate 276 has a single optical axis, and the optical axis (eg, slow axis) of the quarter-wave plate 276 has an optical axis angle relative to the optical axis of the polarizing plate 260 . In some embodiments, the angle between the optical axes ranges from 0 degrees to 180 degrees. In some embodiments, the angle between the optical axes is 45 degrees. In some embodiments, the angle between the optical axes is 40 degrees to 50 degrees.

In this embodiment, in the incident wavelength range of 450 nm to 650 nm, the retardation wavelength of the quarter wave plate 276 is between 100 nm and 160 nm.

In addition, similar to the previous embodiments, the quarter-wave plate 276 has a circular deflection conversion rate with an absolute value less than 0.8 or between 0.82-0.92 in the incident wavelength range of 450 nm to 650 nm without being close to the theoretical value ( e value=1). In this way, it is ensured that the reflectance of the polarizing element 250 is less than 6%, or less than 5.5%, and the total reflectance of the polarizing element 250 and the optical touch element 210 can be less than 7%. Alternatively, the optical characteristics of the quarter-wave plate 276 in this embodiment and the optical characteristics after being combined with the touch element are the same as those in the previous embodiment, and will not be described again.

In another embodiment of the present invention, the polarizing element 250 may also include a polymer film-type quarter-wave plate or a polymer film-type quarter-wave plate. A combination with a polymer film-type half-wave plate. Polymer membrane materials can be: PC, CPI or COP, etc. That is to say, the present invention can be implemented regardless of the material or stack of the polarizing element 250 as long as it is the same as the previous embodiment.

To sum up, the present disclosure provides a touch display module including a polarizing element with a reflectivity of less than 6% or less than 5.5%. The polarizing element uses a liquid crystal-coated phase retardation film assembly, which reduces the overall thickness. In addition, the absolute value of the circular polarization conversion rate (e value) of the liquid crystal-coated phase retardation film assembly is greater than 0.8 and does not need to be close to the theoretical ideal value, so that the linearly polarized light passing through the polarizing element is converted into circularly polarized light or close to circularly polarized light. , thereby reducing reflected light; in addition, the combined reflectivity of the polarizing element and the touch element can be less than a specific value in the wavelength range that the human eye is sensitive to, for example, the total reflectance is less than 7%, or less than 6%, improving the user's vision. and operational experience.

The embodiments disclosed above are not intended to limit the disclosure. Anyone skilled in the art can make various changes and modifications without departing from the spirit and scope of the disclosure, and all of them are protected by the disclosure. . Therefore, the scope of protection of the present disclosure shall be subject to the scope of the appended patent application.

100,200:Touch display module

110,210: Optical touch components

120,220:Display unit

150,250: Polarizing element

160,260:Polarizer

170,270: Phase retardation film assembly

173:Half wave plate

176,276: Quarter wave plate

300: Reflective surface

a1, a2, a3: optical axis

a,b,c,d: data points

D1, D2: direction

L:Light

L1: incident light

L2: linearly polarized light

L3: Circularly polarized light

L1’: reflected light

L2’: linearly polarized light

L3’: circularly polarized light

θ1, θ2: angle

In order to make the above and other objects, features, advantages and embodiments of the present disclosure more obvious and understandable, the accompanying drawings are described as follows: Figure 1 illustrates a schematic cross-sectional view of a touch display module according to an embodiment of the present disclosure; Figure 2 shows an exploded schematic diagram of a polarizing element according to an embodiment of the present disclosure; Figure 3 is a schematic diagram illustrating the angle between the optical axes of a polarizing element according to an embodiment of the present disclosure; FIG. 4 illustrates a relationship between a circular polarization conversion rate and a reflectance of a polarizing element according to an embodiment of the present disclosure; Figure 5 shows a relationship between the absolute value of a circular deflection conversion rate and a reflectivity; Figure 6 illustrates a relationship diagram of a touch display module corresponding to different incident wavelengths and corresponding reflectivity according to an embodiment of the present disclosure; and FIG. 7 illustrates a schematic cross-sectional view of a touch display module according to an embodiment of the present disclosure.

100:Touch display module

110: Optical touch components

120:Display unit

150:Polarizing element

160:Polarizer

170: Phase retardation film assembly

173:Half wave plate

176: Quarter wave plate

D1, D2: direction

Claims (10)

A touch display module includes: a touch element; and a polarizing element disposed on the touch element. The polarizing element includes: a linear polarizer; and a phase retardation film assembly. When an ambient light passes through The linear polarized light generated by the linear polarizer is converted into a circular polarized light by the phase retardation film assembly, wherein the ratio of the linear polarized light converted into the circular polarized light is defined as a circular polarization conversion rate of the phase retardation film assembly, wherein between 450nm and 650nm In the wavelength range between 450 nm and 650 nm, the absolute value of the circular polarization conversion rate is greater than 0.8, and in the wavelength range between 450 nm and 650 nm, the reflectivity of the ambient light passing through the polarizing element is less than 6%. The touch display module of claim 1, wherein the touch element includes: a touch sensor composed of silver nanowires and/or polymer films, which is located on the linear polarizer or the phase On the retardation film assembly. The touch display module as described in claim 2, wherein the combination of the touch element and the polarizing element has a total reflectivity in the wavelength range between 450nm and 650nm, and the total reflectance is less than 7% or less than 6 %; or in the wavelength range of 450nm to 650nm, the refractive index change rate caused by the polarizing element before and after being combined with the touch element is between 0% and within the range of 15%. The touch display module as claimed in claim 1, wherein the phase retardation film assembly is composed of a positive dispersion type half-wave plate and a positive dispersion type quarter-wave plate. The touch display module as described in claim 4, wherein an optical axis angle of the half-wave plate relative to the linear polarizer is in the range of 10 degrees to 15 degrees, and the quarter-wave plate is relative to the linear polarizing plate. An optical axis angle of the linear polarizing plate is in the range of 65 degrees to 75 degrees. The touch display module as claimed in claim 1, wherein the phase retardation film assembly is composed of a reverse dispersion type quarter wave plate. The touch display module of claim 6, wherein an optical axis angle of the quarter-wave plate relative to the linear polarizer is 45 degrees. The touch display module according to claim 1, wherein the phase retardation film assembly includes a liquid crystal phase retardation film or a polymer film type phase retardation film. The touch display module as described in claim 1, wherein in the wavelength range between 450nm and 650nm, the absolute value of the circular polarization conversion rate is in the range of 0.8 to 0.95, wherein between 450nm and 650nm In the wavelength range between nm, the reflectivity of the ambient light passing through the polarizing element is less than 5.5%. A touch display module includes: a touch element; and a polarizing element disposed on the touch element. The polarizing element includes: a linear polarizing plate; and a phase retardation film assembly. When an ambient light passes through The linearly polarized light generated by the linear polarizer is converted into a circularly polarized light by the phase retardation film assembly, wherein the proportion of the linearly polarized light converted into the circularly polarized light is defined as a circular polarization conversion rate of the phase retardation film assembly, wherein at a wavelength of 550nm , the absolute value of the circular polarization conversion rate is greater than 0.9, and at a wavelength of 550 nm, the reflectance of the ambient light passing through the polarizing element is less than 5%.

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