CN115617190A

CN115617190A - Touch control display module

Info

Publication number: CN115617190A
Application number: CN202110805606.2A
Authority: CN
Inventors: 刘明宗; 杨宜龙; 张雅菁; 萧博友; 刘胜发; 陈威州; 王雪芬; 柯涌彬; 林家瑞; 刘少杰; 张雪龙; 许贤斌
Original assignee: TPK Advanced Solutions Inc
Current assignee: TPK Advanced Solutions Inc
Priority date: 2021-07-16
Filing date: 2021-07-16
Publication date: 2023-01-17
Also published as: JP2023013912A; KR20230012952A

Abstract

A touch display module comprises a touch element and a polarization element. The polarizing element includes a polarizing plate and a phase retardation film assembly. The phase retardation film assembly has a circular polarization conversion ratio with an absolute value larger than 0.8. The reflectivity of the polarizing element is less than 6%, and the total reflectivity of the touch control element and the polarizing element is less than 7%. Therefore, the visual and operation experience of the touch display module is improved, and the product cost is not excessively increased.

Description

Touch display module

Technical Field

The present disclosure relates to a touch display module.

Background

The organic light emitting diode display has the advantages of low power consumption, high color vividness, high contrast ratio and the like, can provide better visual enjoyment for people, and has the greatest challenge of effectively resisting reflected light generated by incident light from the external environment and reducing troubles in the aspect of display. One solution is to reduce the amount of ambient light reflected from the display by mounting a circular polarizer as an anti-reflection sheet. The theoretical principle of the circular polarizer adopting the combination of the quarter-wave plate (QWP for short) and the linear polarizer is as follows: the external environment light incident to the display is circularly polarized, the incident circularly polarized light (ex. Left-handed light) is reflected by the electrodes of the display and then is inverted into circularly polarized light (ex. Right-handed rotation) with opposite rotation direction, and the circularly polarized light (right-handed rotation) with opposite rotation direction passes through the quarter wave plate again and becomes linearly polarized light orthogonal to the polarization direction of the linear polarizer, so that the linearly polarized light orthogonal to the polarization direction of the linear polarizer cannot be emitted by the linear polarizer, and the reflection caused by the external environment light is eliminated or reduced, so that the problems of reflection interference or brightness unevenness of a display picture are avoided. From the above principle, the circular polarization of the external ambient light by the anti-reflective sheet is the first step of the anti-reflective mechanism, so it is one of the important factors of the anti-reflective effect. Generally speaking, the higher the circular polarization conversion ratio, the better the antireflection effect.

For example, TWI580995B (TW' 995) proposes an ambient light resistant reflective film comprising: a linearly polarizing layer and an optically active liquid crystal layer formed on the linearly polarizing layer, and examples 1-4 of table 2 from TW'995 show that the lowest value of reflectance of light is 7.62% when the circular polarization conversion ratio is close to 1 (i.e., linear polarization is fully converted to circular polarization). However, the present invention considers that the reflectivity of about 8% cannot meet the increasingly fine display requirements, and especially, the present invention is popular with the users for high resolution and high quality films such as 4K and 8K. On the other hand, assembling touch sensing electrodes on a display to become a touch display screen is one of important human-computer interfaces in modern society, and the touch sensing electrodes are also factors causing ambient light reflection. In summary, the reflectance of the environmental light reflection resistant film proposed in TW'995 is too high, and thus the high-level display requirement may not be satisfied after the display and the touch sensing electrodes are combined. In other words, it is a major challenge for those skilled in the art to obtain an antireflection sheet with a lower reflectance.

On the other hand, the circular polarization conversion ratios of the samples 1 to 4 of TW'995 were close to 1, which is equivalent to an ideal value, and it is assumed that the liquid crystal material should be a laboratory-grade liquid crystal material, which is very expensive and not suitable for commercial use. In the commercial market, the material specification of the electronic product is not so close to the ideal value due to cost considerations, that is, if the specification/cost of the general commercial product is considered, the circular polarization conversion ratio of the exemplary embodiments 1-4 of TW'995 is inevitably reduced (for example, the circular polarization conversion ratio is reduced to 0.9), and it is conceivable that the aforementioned light reflectivity is also increased, and the requirement of low reflectivity is further not satisfied.

Further, the optically active liquid crystal layer employed in TW '995 is a cholesteric liquid crystal that operates on the principle of laminating multiple liquid crystals of different axial directions together to achieve circular polarization of light, as shown in TW'995 FIG. 2, and thus. The TW '995 multilayer liquid crystal structure causes the problem that the thickness of the ambient light resistant reflective film cannot be reduced, and thus cannot satisfy the user's thin and light requirements for the portable device.

Disclosure of Invention

The touch display module disclosed by the embodiment of the disclosure can have a reflectivity low enough to reduce the reflection of light from the external environment and avoid influencing the display quality.

The technical scheme adopted by the disclosure is as follows:

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

According to one or more embodiments of the present disclosure, the touch device includes a touch sensor composed of a nano silver wire and/or a polymer film. The touch sensor is arranged on the linear polarizer or the phase delay film assembly.

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

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

In some embodiments, the half-wave plate is at an optic axis angle in the range of 10 to 15 degrees to the linear polarizer and the quarter-wave plate is at an optic axis angle in the range of 65 to 75 degrees to the linear polarizer.

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

In some embodiments, the quarter-wave plate is at a 45 degree angle to the optical axis of the linear polarizer.

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, the absolute value of the circular polarization conversion rate is in a range of 0.8 to 0.95 at a wavelength range of 450nm to 650nm, wherein the reflectance of ambient light through the polarizing element is less than 5.5% at the wavelength range of 450nm to 650 nm.

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

Therefore, according to the embodiment of the invention, the circular polarization conversion rate of the polarization element does not need to be close to a theoretical value, so that the reflection of incident light of an external environment by the touch display module can be reduced, the visual and operation experience of the touch display module is improved, and the product cost cannot be excessively increased.

The foregoing is merely illustrative of the problems to be solved, solutions to problems, and effects produced by the present disclosure, and the details of the present disclosure will be described in detail in the following examples and related drawings.

Drawings

The foregoing and other objects, features, advantages and embodiments of the disclosure will be apparent from the following more particular description of the embodiments, as illustrated in the accompanying drawings in which:

FIG. 1 is a schematic cross-sectional view of a touch display module according to one embodiment of the present disclosure;

FIG. 2 is an exploded view of a polarizer according to an embodiment of the present disclosure;

FIG. 3 is a schematic diagram illustrating an included angle between optical axes of a polarizer according to an embodiment of the present disclosure;

FIG. 4 is a graph illustrating a relationship between a circular polarization conversion rate and a reflectivity of a polarizer according to an embodiment of the present disclosure;

FIG. 5 is a graph showing the relationship between the absolute value of the circular deviation conversion rate and a reflectance;

FIG. 6 is a graph illustrating a relationship between different incident wavelengths and corresponding reflectivities of a touch display module according to an embodiment of the present disclosure; and

fig. 7 is a schematic cross-sectional view illustrating a touch display module according to an embodiment of the present disclosure.

[ notation ] to show

100,200 touch display module

110,210 touch control element

120,220 display unit

150,250 polarizing element

160,260 polarizing plate

170,270 phase retarder film Assembly

173 one-half wave plate

176,276 quarter wave plate

300 reflective surface

a1, a2, a3 optical axis

a, b, c, d data points

D1, D2 directions

L is light

L1, L2, L3, L1', L2', L3': light/ray

Angle theta 1, theta 2

Detailed Description

In the following description, for purposes of explanation, numerous implementation details are set forth in order to provide a thorough understanding of the various embodiments of the present disclosure. It should be understood, however, that these implementation details should not be used to limit the disclosure. That is, in the disclosed embodiments, such implementation details are not necessary. In addition, for the sake of simplicity, some conventional structures and elements are shown in the drawings in a simple schematic manner.

For a display device, reflection of light from the external environment can affect the visual experience of the user. For a user of the touch display module, the reflection of the external ambient light further affects the operation experience. The range of wavelengths covered by the external ambient light is very wide, and the present disclosure is directed to the anti-reflection optical modulation of the wavelength band (e.g., 450nm-650 nm) to which the human eye is more sensitive.

The disclosure relates to a touch display structure, which can reduce the reflection of external ambient light, thereby reducing the interference from the reflection of the external ambient light to the vision and operation experience, and maintaining the overall thickness to be thin and light. The disclosure can obtain an anti-reflection element with low reflectivity without reaching or approaching an ideal circular polarization conversion rate (i.e., the circular polarization conversion rate is equal to 1) for a polarization element in a touch display structure, thereby having a good balance between cost and product quality.

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

As shown in fig. 1, in an embodiment of the present disclosure, a touch display module 100 at least includes a touch device 110 and a polarization device 150.

In the present embodiment, the touch device 110 and the display unit 120 can be assembled, for example, by using an optical adhesive (OCA) to attach and fix the two.

In some embodiments, the display unit 120 includes an Organic Light-Emitting Diode (OLED), a mini-LED display, and the like. The organic light emitting diode display can have advantages of low power consumption, high color vividness, and high contrast. In some embodiments, the one or more organic light emitting diodes of the display unit 120 can be configured as an Active-matrix organic light-emitting diode (AMOLED) to display images and signals.

As shown in fig. 1, in an embodiment of the present disclosure, the display unit 120 can emit light L in a direction D1 to display a picture, that is, a user can receive a signal emitted by the display unit 120 in the direction D1.

In some embodiments, the touch device 110 may include a touch sensor. The touch sensor can sense a touch or a gesture of a user, thereby implementing a touch operation of the touch display module 100.

In some embodiments of the present disclosure, the touch device 110 includes an electrode formed by patterning a transparent conductive layer or a transparent conductive film, which has a high transmittance, for example, a transmittance (Transmission) of more than about 88%, 90%, 91%, 92%, 93% or more in visible light (e.g., wavelength between 400nm and 700 nm). In some embodiments, the transparent conductive layer or the transparent conductive film includes an ITO material, a Silver Nanowire (SNW) material, or the like.

Please refer back to fig. 1. As shown in fig. 1, the polarization element 150 is disposed on the touch element 110. In some embodiments of the present disclosure, the polarizer 150 can convert the ambient light (e.g., the light L1) from the external environment into polarized light, so as to reduce the reflection of the ambient light and the emission along the direction D1, which affects the view of the user, as will be discussed in detail later.

As shown in fig. 1, the polarizing element 150 may include a linear polarizer 160 and a phase retardation film assembly 170. In the present embodiment, the phase retardation film assembly 170 is located between the light emitting surface of the optical touch device 110 and the polarizer 160.

The linear polarizer 160 can be arranged 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 not limited thereto.

In some embodiments, the phase retardation film assembly 170 may include one or more phase retardation films (retarders). In the present embodiment, the retardation film assembly 170 is composed of a positive dispersion type Half Wave Plate (HWQ) 173 and a positive dispersion type Quarter Wave Plate (QWP) 176. In this embodiment, the quarter wave plate 176 and the half wave plate 173 are both single-layer liquid crystal coatings, such as commercially available products: a quarter-wave plate 176 and a half-wave plate 173 (e.g., DNP; DNP _ HWP and DNP _ QWP) made of Reactive Mesogen (RM) Reactive liquid crystals.

In this way, the retardation film assembly 170 can be regarded as a liquid crystal coating type retardation device, and since the thickness of the coating type liquid crystal is only several micrometers (um), the entire thickness can be reduced. Compared with the stacked thickness of the multiple layers of cholesteric liquid crystals 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 retardation effect, so that the requirement of thinning products can be satisfied.

Referring to fig. 2, when the external ambient light L1 is incident, the light is incident in a direction D2 substantially opposite to the direction D1 (i.e. the display direction), and the external ambient light is converted into linearly polarized light L2 by the polarizing plate 160. The linearly polarized light L2 is then converted into circularly polarized light L3 (e.g., left-handed light) through the half wave plate 173 and the quarter wave plate 176. When the circularly polarized light L3 is reflected by the touch device 110 or the display unit 120, a reversed circularly polarized light L3' (e.g., right-handed rotation) is formed. At this time, the reversed circularly polarized light L3 'passes through the phase retardation film assembly 170 to form linearly polarized light L2' perpendicular to the optical axis of the linear polarizer 160, and since the polarization angle is orthogonal, the polarized light L2 'cannot be emitted from the linear polarizer 160, that is, in an ideal state, no reflected light L1' is generated. As such, the Polarizer 150 is optically called a Circular Polarizer (CPOL), which eliminates or reduces reflected light in optical applications, and is also called an anti-reflective element.

In short, by the arrangement of the polarization element 150, the external environment light is converted into circularly polarized light, and then the circularly polarized light is reflected again, and the reflected circularly polarized light will be blocked by the linear polarizer 160 due to the polarization angle. Thus, the external ambient light reflection can be prevented from affecting the visual effect of the touch display module 100. It should be noted that the linearly polarized light can be converted into an ideally completely circularly polarized light or elliptically polarized light close to the circularly polarized light by the polarizing element 150. In this way, the circular polarization conversion rate or the circular polarization conversion rate (e-value) of the phase retardation film assembly 170 can be defined according to the ratio of linearly polarized light L2 converted into circularly polarized light, and since the circular polarization conversion rate has a positive/negative value according to the left-hand rotation or the right-hand rotation, the circular polarization conversion rate of the present invention is explained as an absolute value for convenience of description.

For example, when the polarized light L3 is right-handed circularly polarized light, the circular polarization conversion rate of the phase retardation film assembly 170 is +1 (i.e. complete conversion); when the polarized light L3 is right-handed elliptically polarized light, i.e., a combination of a portion of linearly polarized light and a portion of circularly polarized light, the circular polarization conversion rate of the phase retardation film assembly 170 is between +1 and 0; similarly, when the polarized light L3 is left-handed circularly polarized light, the circular polarization conversion rate of the phase 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 circular polarization conversion rate is equal to 1.

In some embodiments, the absolute value of the circular polarization conversion ratio of the phase retardation film assembly 170 is less than 1, i.e., the phase retardation film assembly can still provide the anti-reflection effect without approaching the complete circular polarization conversion. Specifically, in some embodiments, in the wavelength range of 450 to 650nm, the absolute value of the circular polarization conversion rate of the phase retardation film assembly 170 is still greater than 0.8 (which is not close to the ideal value), and the reflectivity of the touch display module 100 as a whole can be effectively reduced, for example, the reflectivity is less than 6% or less than 5.5%.

To further illustrate, when the absolute value of the circular polarization conversion rate of the 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 is a schematic diagram illustrating included optical axis angles θ 1 and θ 2 formed by a polarizer 150 according to an embodiment of the disclosure. In fig. 3, the optical axis a1 corresponds to the linearly polarizing plate 160. The optical axis a2 of the polarizer 150 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 have only single optical axes a2 and a3, respectively, and the optical axes a2 and a3 can be slow axes.

The optical axis a2 has an included angle θ 1 with respect to the optical axis a1 of the linearly polarizing plate 160. The optical axis a3 has an included optical axis angle θ 3 with respect to the optical axis a1 of the linearly polarizing plate 160. In some embodiments, the included optic axis angles θ 1 and θ 2 may range between 0 degrees and 180 degrees. In the present embodiment, the included optical axis angle θ 1 is 15 degrees, and the included optical axis angle θ 2 is 75 degrees, but not limited thereto. In one embodiment, the included optic angle θ 1 is 10 to 15 degrees, and the included optic angle θ 2 is 65 to 75 degrees, but not limited thereto.

Referring back to fig. 2, an incident light L1 is incident on a polarization device 150, passes through a reflection surface 300, such as a half mirror (3D Lens) with a reflectivity of about 50-60%, and then passes through the polarization device 150 to be a reflected light L1' according to an embodiment of the present disclosure. Fig. 4 is a graph showing the relationship between the absolute value of the circular polarization conversion rate (e value) and the reflectance (R%) of the polarizer 150 measured according to the above embodiment.

As shown in fig. 4 and table 1 below, the absolute values of the circular polarization conversion (e value) of the polarization element 150 of the present disclosure are all above 0.8 corresponding to the incident light L1 with the incident wavelength ranging from 450nm to 650nm, as shown by the dashed line; and a reflectance (R%) of less than 6%, or less than 5.5% for an incident light L1' in a range of 450nm to 650 nm.

TABLE 1

Wavelength (nm)	e value	Reflectivity R%
			450	0.85	5.2
475	0.91	5.2
			500	0.92	5.0
525	0.92	4.6
			550	0.9	4.9
575	0.89	4.9
			600	0.87	5.2
625	0.85	5.4
			650	0.82	5.5

Thus, the absolute value of the circular polarization conversion (e value) of the polarization element 150 of the present embodiment is greater than 0.8 when the incident light L1 with the incident wavelength ranging from 450nm to 650nm is incident, so that the reflectivity in the range from 450nm to 650nm, which is sensitive to human eyes, is less than 6%, or less than 5.5%. More specifically, the absolute value of the circular polarization conversion ratio (evalue) of the polarization element 150 of the present embodiment only needs to be between 0.82 and 0.92 without approaching the theoretical value (evalue = 1) corresponding to the incident light L1 with the incident wavelength ranging from 450nm to 650nm, so that the reflectance in the range of 450nm to 650nm to which the human eye is sensitive can be less than 6%, or less than 5.5%, thereby achieving an advantage in commercial/industrial production cost. In one embodiment, the absolute value of the circular polarization conversion ratio (e value) of the polarizing element 150 only needs to be between 0.8 and 0.95 without approaching the theoretical value (e value = 1), so that the reflectance in the 450nm to 650nm range, to which the human eye is sensitive, is less than 6%, or less than 5.5%.

More specifically, the absolute value of the circular polarization conversion (e value) of the polarization element 150 of the present embodiment only needs to be 0.9 or more and does not need to be close to the theoretical value (evalue = 1) at the incident light L1 with the incident wavelength of 550nm, so that the reflectance at 550nm, which is sensitive to the human eye, can be made less than 6%, or less than 5.5%, or less than 5%. More specifically, when the incident light L1 with the incident wavelength of 550nm is used, the absolute value of the circular polarization conversion (e value) of the polarization element 150 of the present embodiment is only 0.9 or more, and does not need to be close to the theoretical value (e value = 1), so that the reflectivity of 550nm, which is sensitive to the human eye, is 4.9%, which is advantageous in commercial/industrial production cost. In summary, the absolute value of the circular polarization conversion rate (e value) of the polarization element 150 of the present embodiment only needs to be 0.9 to 0.95 without being close to the theoretical value (e value = 1), so that the reflectance at 550nm, which is sensitive to the human eye, can be between 4.5 and 5.0%.

FIG. 5 is a graph showing the relationship between the absolute value of the circular deviation conversion (evalue) and the reflectance. At an incident light ray in the range of 450nm to 650nm, the horizontal axis is the liquid crystal coated type phase retarder assembly set to the circularly polarized conversion ratio (e value) using different absolute values of the present disclosure, and the vertical axis is the reflectance (R%) of the polarizing element using the corresponding phase retarder assembly. It can be seen that, once the absolute value of the circular polarization conversion ratio (e value) is less than 0.8, it is ensured that the reflectance (R%) of the polarizing element is less than 6% when the wavelength of the incident light is in the range of 450nm to 650 nm; when the slow axis of the half wave plate 173 is included at an angle exceeding 15 degrees with respect to the optical axis a1 of the linear polarizer 160 or the slow axis of the quarter wave plate 176 is included at an angle exceeding 75 degrees with respect to the optical axis a1 of the linear polarizer 160, there is a possibility that the absolute value of the circular polarization conversion ratio (e value) is less than 0.8 and the comparative example (data points a, b, c, d in fig. 5) having a reflectance (R%) of more than 6% at a wavelength range of 450nm to 650nm is caused. Other data points in fig. 5 satisfy the above embodiments, and are not repeated herein.

According to an embodiment of the present disclosure, after the touch device 110 is assembled to the polarizer 150, a test for measuring the circular polarization conversion rate and the light reflectance within a wavelength range of 450nm to 650nm is performed. In one embodiment, the combination of the touch device 110 and the polarizer 150 can be regarded as an optoelectronic device, i.e. an integrated device having both optical and electrical functions, where the electrical function refers to a touch sensing function, and the optoelectronic device has a total reflectivity, since the touch device 110 also causes light reflection, the total reflectivity of the optoelectronic device is slightly larger than that of the polarizer 150, and the total reflectivity of the product must be small enough not to affect the display quality. The testing method of the present embodiment can refer to the method shown in fig. 2 and the related description, and is not described herein again.

In one embodiment, the touch device 110 at least includes a touch electrode made of a nano silver wire and/or a polymer film, which is described in US20190227650A, CN101292362, and the like. As shown in fig. 6, in the range of 450nm to 650nm to which human eyes are sensitive, the total reflectance of the optical touch device 110 and the polarizer 150 can be less than 7%, as shown in table 2 below.

TABLE 2

* Note: experimental figures possibly caused by instrumental errors

As shown in the above table, in the incident light L1 with the corresponding incident wavelength ranging from 450nm to 650nm, the reflectivity of the photoelectric element of the present embodiment in the range from 450nm to 650nm, which is sensitive to human eyes, is less than 7% or less than 6%. In summary, the reflectivity of the photoelectric element of the embodiment of the invention in the range of 450nm to 650nm sensitive to human eyes is 5% -6%.

More specifically, the reflectance of the photoelectric element of the present embodiment at 550nm corresponding to the incident light L1 with an incident wavelength of 550nm is less than 6%, or less than 5.5%. More specifically, the reflection rate of the photoelectric element of the present embodiment at a wavelength of 550nm is 5.3% with respect to the incident light L1 having a wavelength of 550 nm. In summary, the reflectance of the photoelectric element of the embodiment of the invention at a wavelength of 550nm is between 5.0% and 5.5%.

In addition, it is common that characteristics may affect each other when two elements having different functions are combined. The embodiment of the present invention can find that the touch electrode formed by the nano silver wires and/or the polymer film is combined with the polarizer 150 without excessively deteriorating the characteristics of the polarizer 150. Specifically, in the embodiment of the present invention, when the touch electrode composed of the silver nanowires and/or the polymer film is combined with the polarizer 150, the reflectance change rate is 15% or less at a wavelength of 450nm to 650nm as compared with the polarizer 150; in summary, the reflectivity of the photoelectric element of the embodiment of the invention varies by 0% to 15%, 0% to 13%, 0% to 8%, or 0% to 2% at a wavelength of 450nm to 650 nm.

More specifically, the reflectance change rate is 10% or less at the corresponding wavelength of 550 nm; more specifically, the reflectance change rate was 8% at the corresponding wavelength of 550 nm. In summary, the reflectivity of the photoelectric element of the embodiment of the invention changes by 0% -10%, 5% -10% or 5% -8% at a wavelength of 550 nm.

In some embodiments, a transparent protective cover can be further disposed on the polarizer 150.

Fig. 7 is a schematic cross-sectional view illustrating a touch display module 200 according to an embodiment of the disclosure.

In the present embodiment, as shown in fig. 7, the touch display module 200 includes an optical touch device 210, a display unit 120, and a polarizer 250, and the polarizer 250 includes a polarizer 260 and a liquid crystal coating type retardation film assembly 270.

The difference with the previous embodiment is at least: the phase retardation film assembly 270 may include a phase retardation film (Retarder). In the present embodiment, the phase retardation film assembly 270 is composed of only the inverse dispersion type quarter wave plate 276. In this embodiment, the quarter-wave plate 276 is a single layer of liquid crystal coating, such as commercially available: a quarter wave plate 276 (DNP; DNP _ QWP) made of Reactive Mesogen (RM) reaction type liquid crystal. In this embodiment, the quarter-wave plate 276 has a single optical axis, and the optical axis (e.g., slow axis) of the quarter-wave plate 276 has an included angle with respect to the optical axis of the polarizer 260. In some embodiments, the included optic angle ranges from 0 to 180 degrees. In some embodiments, the included optic axis angle is 45 degrees. In some embodiments, the included angle of the optical axis is 40 to 50 degrees.

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

Further, as with the previous embodiments, the quarter-wave plate 276 has a circular polarization conversion ratio in the 450nm to 650nm incident wavelength range of less than 0.8, or between 0.82 and 0.92, in absolute value, without being close to the theoretical value (e value = 1). Thus, it is ensured that the reflectivity of the polarizer 250 is less than 6%, or less than 5.5%, and the total reflectivity of the polarizer 250 and the optical touch device 210 can be less than 7%. Alternatively, the optical characteristics of the quarter-wave plate 276 and the optical characteristics after the quarter-wave plate is combined with the touch device are the same as those of the previous embodiments, and are not described herein again.

In another embodiment of the present invention, the polarizer 250 may also include a quarter-wave plate of a polymer film type (film-type), or a combination of the quarter-wave plate of the polymer film type (film-type) and a half-wave plate of the polymer film type (film-type). The polymer film material can be: PC, CPI or COP, etc. That is, the present invention can be implemented as long as it is the same as the foregoing embodiment, regardless of the material or laminate of the polarizing element 250.

In summary, the present disclosure provides a touch display module including a polarizer with a reflectivity less than 6% or less than 5.5%. The polarizing element uses a liquid crystal coating type phase retardation film assembly, and the overall thickness is reduced. In addition, the absolute value of the circular polarization conversion ratio (e value) of the liquid crystal coating type phase retardation film assembly is larger than 0.8 without being close to a theoretical ideal value, so that the linear polarization passing through the polarizing element is converted into circular polarization or nearly circular polarization, thereby reducing the reflected light; in addition, the total reflectivity of the polarizer and the touch device can be smaller than a specific value in the wavelength range to which human eyes are sensitive, for example, the total reflectivity is smaller than 7%, or smaller than 6%, so that the visual and operational experience of a user is improved.

The above-described embodiments are not intended to limit the disclosure, and those skilled in the art can make various changes and modifications without departing from the spirit and scope of the disclosure. Therefore, the protection scope of the present disclosure should be determined by the scope of the appended claims.

Claims

1. A touch display module, comprising:

a touch control element; and

a polarization element disposed on the touch element, the polarization element comprising:

a linear polarizer; and

a phase retarder assembly, wherein a linearly polarized light generated when an ambient light passes through the linear polarizer is converted into a circularly polarized light by the phase retarder assembly, wherein a ratio of the linearly polarized light to the circularly polarized light is defined as a circular polarization conversion ratio of the phase retarder assembly,

wherein the absolute value of the circular polarization conversion is greater than 0.8 at a wavelength range between 450nm and 650nm,

wherein the reflectance of the ambient light through the polarizing element is less than 6% at a wavelength range between 450nm and 650 nm.

2. The touch display module of claim 1, wherein the touch element comprises:

a touch sensor composed of nano silver wires and/or polymer films, which is arranged on the linear polarizer or the phase retardation film assembly.

3. The touch display module of claim 2, wherein the combination of the touch element and the polarizer element has a total reflectance in a wavelength range of 450nm to 650nm, the total reflectance being less than 7% or less than 6%; or under the wavelength range of 450nm to 650nm, the refractive index change rate of the polarizing element before and after being combined with the touch control element is between the range of 0% to 15%, the range of 0% to 13%, the range of 0% to 8% or the range of 0% to 2%.

4. The touch display module of claim 1, wherein the retarder film assembly comprises a positive dispersion type quarter-wave plate and a positive dispersion type quarter-wave plate.

5. The touch display module of claim 4, wherein an optic axis angle of the half-wave plate with respect to the linear polarizer is in a range of 10 degrees to 15 degrees, and an optic axis angle of the quarter-wave plate with respect to the linear polarizer is in a range of 65 degrees to 75 degrees.

6. The touch display module of claim 1, wherein the phase retardation film assembly is formed of a quarter-wave plate of an inverse dispersion type.

7. The touch display module of claim 6, wherein an optic axis angle of the quarter-wave plate with respect to the linear polarizer is 45 degrees.

8. The touch display module of claim 1, wherein the retarder film assembly comprises a liquid crystal type retarder film or a polymer film type retarder film.

9. The touch display module of claim 1, wherein the absolute value of the circular polarization conversion rate is in a range of 0.8 to 0.95 at a wavelength range of 450nm to 650nm, and wherein the reflectance of the ambient light passing through the polarization element is less than 5.5% at a wavelength range of 450nm to 650 nm.

10. A touch display module, comprising:

a touch control element; and

a linear polarizer; and

a phase retardation film assembly, wherein when a linear polarization generated by an ambient light passing through the linear polarizer is converted into a circular polarization by the phase retardation film assembly, a ratio of the linear polarization to the circular polarization is defined as a circular polarization conversion ratio of the phase retardation film assembly,

wherein the absolute value of the circular polarization conversion is greater than 0.9 at a wavelength of 550nm,

wherein the reflectance of the ambient light through the polarizing element is less than 5% at a wavelength of 550 nm.