WO2019051705A1

WO2019051705A1 - Display module

Info

Publication number: WO2019051705A1
Application number: PCT/CN2017/101706
Authority: WO
Inventors: 凌严; 朱虹
Original assignee: 上海箩箕技术有限公司
Priority date: 2017-09-14
Filing date: 2017-09-14
Publication date: 2019-03-21

Abstract

A display module, comprising: an optical sensor (110) comprising a flexible plastic substrate (111) and a device layer (112) located on the flexible plastic substrate (111); a self-luminous display panel (120) located above the optical sensor (110); a point light source (130) located at one side of the self-luminous display panel (120) and of the optical sensor (110); a protective cover plate (140) located above the point source (130) and the self-luminous display panel (120). The surface of the protective cover plate (140) facing away from the self-luminous display panel (120) is a sensing surface (141). Light (131) generated by the point light source (130) is obliquely projected to the protective cover plate (140) and is transmitted to the sensing surface (141), to form reflected light (132) carrying fingerprint information on the sensing surface (141). The optical sensor (110) is used for collecting the reflected light (132) to obtain a fingerprint image. The use of the flexible plastic substrate (111) can reduce the thickness of the optical sensor (110) while ensuring the manufacturing yield of the display module, so that the purpose of reducing the thickness of the display module is achieved, and both a better manufacturing yield and module thinning can be achieved.

Description

Display module

Technical field

The present invention relates to the field of optical fingerprint recognition, and in particular, to a display module.

Background technique

The fingerprint imaging recognition technology is a technique of acquiring a fingerprint image of a human body through a fingerprint sensor and then comparing it with existing fingerprint imaging information in the system to determine whether it is correct or not, thereby realizing the identity recognition technology. Due to its ease of use and the uniqueness of human fingerprints, fingerprint recognition technology has been widely used in various fields. For example, the public security bureau, customs and other security inspection areas, building access control systems, and consumer goods such as personal computers and mobile phones.

Fingerprint imaging recognition technology can be realized by various techniques such as optical imaging, capacitive imaging, and ultrasonic imaging. Relatively speaking, optical fingerprint imaging technology has relatively good imaging effect and relatively low equipment cost.

On the other hand, in the prior art, the self-luminous display panel is widely used in various electronic products due to its small size, light weight, low radiation and the like. In the prior art, a reference has been made to combine a self-luminous display panel with an optical fingerprint imaging film layer, thereby enabling the display panel to integrate fingerprint recognition and image display functions.

However, the thickness of the display module having the fingerprint recognition function tends to be large, and the existing thinning process causes a high yield loss in the manufacturing process of the display module, and it is difficult to ensure the production yield of the display module. .

Summary of the invention

The problem to be solved by the present invention is to provide a display module that reduces the thickness of the display module while ensuring the yield of the display module.

To solve the above problems, the present invention provides a display module, including:

An optical sensor comprising a flexible plastic substrate and a device layer on the flexible plastic substrate; a self-luminous display panel over the optical sensor; a point light source located in the self-luminous display panel and the optical a side of the sensor; a protective cover plate located above the point light source and the self-luminous display panel; a surface of the protective cover facing away from the self-luminous display panel is a sensing surface, and the point light source is generated The light is obliquely projected onto the protective cover and conducted to the sensing surface, and reflected light carrying fingerprint information is formed on the sensing surface; the optical sensor is configured to collect the reflected light to obtain Fingerprint image.

Optionally, the material of the flexible plastic substrate is polyimide plastic or polyphthalic plastic.

Optionally, the flexible plastic substrate has a thickness of less than or equal to 0.2 mm.

Optionally, the optical sensor is an optical sensor based on an amorphous silicon thin film transistor, an optical sensor based on a low temperature polysilicon thin film transistor, or an optical sensor based on an indium gallium zinc oxide thin film transistor.

Optionally, the optical sensor comprises photosensitive pixels, and the photosensitive device in each of the photosensitive pixels is an amorphous silicon PIN photodiode.

Optionally, the self-luminous display panel is an OLED display panel.

Optionally, the self-luminous panel comprises a plurality of light emitting units, and the light emitting unit comprises a light transmissive area, and the light transmissive area has an area of 5% to 20% of the area of the light emitting unit.

Optionally, the point light source is an infrared light source.

Optionally, the method further includes: a filter layer between the self-luminous display panel and the optical sensor.

Optionally, the filter layer has a transmittance to near-infrared light of greater than 50%.

Optionally, the filter layer has an absorption rate of visible light greater than 50%.

Optionally, the filter layer is an ink layer or a multilayer dielectric reflective layer.

Optionally, the filter layer is an ink layer; the filter layer is formed by screen printing.

Optionally, the filter layer is an ink layer; the filter layer has a thickness of less than 20 μm.

Optionally, the filter layer is a multilayer dielectric reflective layer; the filter layer is formed by sputtering or evaporation.

Optionally, the filter layer is a multilayer dielectric reflective layer; the filter layer has a thickness of less than 5 μm.

Compared with the prior art, the technical solution of the present invention has the following advantages:

The flexible plastic substrate and the device layer are used to form the optical sensor for collecting reflected light formed by the light generated by the point light source on the sensing surface to obtain a fingerprint image. Since the material of the flexible plastic substrate is often a high molecular polymer, it has high toughness, and is less likely to be damaged in the case of a small thickness; therefore, the use of the flexible plastic substrate can ensure the display module. In the case of yield, the thickness of the optical sensor is reduced, thereby achieving the purpose of reducing the thickness of the display module. Therefore, the use of the flexible plastic substrate can better achieve both manufacturing yield and module thinness. Technical requirements.

In an alternative of the present invention, the material of the flexible plastic substrate is polyimide plastic or polyterephthalic plastic. Polyimide plastic or poly-p-dicarboxylic acid plastic has good mechanical properties and strong toughness, and can maintain a small breakage rate even when the thickness is less than or equal to 0.2 mm, so The material of the flexible plastic substrate is set as polyimide plastic or poly-p-dicarboxylic acid plastic, which can effectively reduce the thickness of the optical sensor and maintain good manufacturing yield; furthermore, polyimide plastic or poly It also has good thermal stability performance for stupid dicarboxylic acid plastics, can withstand high temperature, can withstand various process conditions in the semiconductor manufacturing process, is beneficial to ensure the performance of the optical sensor, and is better for fingerprint recognition. The integration with the image display function is beneficial to the high-yield and small-thickness technical requirements; moreover, polyimide plastic or poly-p-dicarboxylic acid plastic has better isolation properties, which can effectively prevent water vapor from penetrating into the Inside the display module, It is beneficial to improve the stability of the formed display module.

In an alternative embodiment of the present invention, the point light source is located on a side of the self-luminous display panel and the optical sensor, and the generated light is obliquely projected onto the sensing surface to form a reflection carrying fingerprint information. Light. Since the light generated by the point light source has strong consistency, the stray light is less; and the point light source is located on one side of the self-luminous display panel and the optical sensor, and the light generated by the point light source is directly transmitted. It is not necessary to transmit the self-luminous display panel and the optical sensor to the sensing surface, so that the light generated by the point light source is less likely to be scattered, and less stray light is formed. The use of the point light source and the position of the point light source can effectively reduce the scattering of the reflected light formed, improve the signal to noise ratio of the reflected light, thereby improving the quality of the obtained fingerprint image, and better. The performance of the display module is improved; and the setting of the point light source can save the use of the light collimation structure, and is better than the technical solution for fingerprint recognition by using the light generated by the self-luminous display panel. The purpose of reducing the thickness of the display module is achieved.

In an optional aspect of the invention, the display module further includes: a filter layer. The filter layer is located between the self-luminous display panel and the optical sensor to prevent the filter layer from affecting an image display function of the self-luminous display panel; the filter layer can ensure that impurities are removed as much as possible Astigmatism, suppressing noise signals caused by stray light; also effectively ensuring the transmittance of the reflected light and ensuring smooth acquisition of the fingerprint image; therefore, the setting of the filter layer can effectively improve the signal collected by the optical sensor The noise ratio is beneficial to the acquisition of high-quality fingerprint images, which is beneficial to better integration of fingerprint recognition and image display.

DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the description of the prior art will be briefly described below. Obviously, the drawings in the following description are only It is a certain embodiment of the present invention, and other drawings can be obtained from those skilled in the art without any creative work.

1 is a schematic cross-sectional view showing an embodiment of a display module of the present invention.

Detailed ways

It can be known from the background art that the existing display module with fingerprint recognition function tends to have a large thickness, and the existing thinning process causes high yield loss in the manufacturing process, and it is difficult to achieve manufacturing yield and module thinning. Take care of both.

In order to solve the technical problem, the present invention provides a display module, by using the flexible plastic substrate, reducing the thickness of the optical sensor under the premise of ensuring the manufacturing yield of the display module, thereby achieving The purpose of reducing the thickness of the display module is to better achieve both the manufacturing yield and the thinning of the module.

The above described objects, features, and advantages of the present invention will be more apparent from the aspects of the invention.

Referring to FIG. 1, a cross-sectional structural view of an embodiment of a display module of the present invention is shown.

The display module includes:

The optical sensor 110 includes a flexible plastic substrate 111 and a device layer 112 on the flexible plastic substrate 111. The self-luminous display panel 120 is located above the optical sensor 110. The point light source 130 is located at the optical sensor 110. a side of the self-luminous display panel 120 and the optical sensor 110; a protective cover 140 located above the point light source 130 and the self-luminous display panel 120; the protective cover 140 facing away from the self-luminous display The surface of the panel 120 is a sensing surface 141. The light 131 generated by the point light source 130 is obliquely projected to the protective cover 140, and is transmitted to the sensing surface 141 to form a carrying on the sensing surface 141. Reflected light 132 having fingerprint information; the optical sensor 110 is configured to collect the reflected light 132 to obtain a fingerprint image.

The flexible plastic substrate 111 and the device layer 112 are configured to form the optical sensor 110 for collecting the reflected light 132 formed by the light generated by the point light source 130 on the sensing surface 141 to obtain a fingerprint. image. Since the material of the flexible plastic substrate 111 is often a high molecular polymer, it has high toughness, and is less likely to be damaged in the case of a small thickness; therefore, the adoption of the flexible plastic substrate 111 can ensure the In the case of displaying the module yield, the thickness of the optical sensor 110 is reduced to achieve the purpose of reducing the thickness of the display module. Therefore, the flexible plastic substrate 111 can be used to better achieve good manufacturing. The technical requirements for rate and module thinning.

The specific technical solutions of the embodiment of the display module of the present invention are described in detail below with reference to the accompanying drawings.

The optical sensor 110 is configured to collect the reflected light 132 and photoelectrically convert the collected reflected light 132 to obtain a fingerprint image.

The flexible plastic substrate 111 is used to form the optical sensor 110 to provide a process operation platform and foundation for the formation of the device layer 112.

Since the material of the flexible plastic substrate 111 is often a high molecular polymer and has high toughness, and the thickness is less likely to be damaged, the optical sensor is formed on the flexible plastic substrate 111. Effectively reducing the thickness of the formed optical sensor can also reduce the yield loss during the formation of the optical sensor, and is advantageous in achieving both manufacturing yield and thinning of the module.

In this embodiment, the thickness of the flexible plastic substrate 111 is less than or equal to 0.2 mm. The thickness of the flexible plastic substrate 111 is not too large. If the thickness of the flexible plastic substrate 111 is too large, the thickness of the optical sensor 110 is too large, which may affect the thickness reduction of the display module, which is disadvantageous for thinning the module.

In this embodiment, the material of the flexible plastic substrate 111 is Polyimide (PI) plastic or Polyethylene Terephthalate (PET) plastic.

Polyimide plastic or polyterephthalic plastic has good mechanical properties and strong toughness, and can maintain a small breakage rate even when the thickness is less than or equal to 0.2 mm, so The material of the flexible plastic substrate 111 is set to polyimide plastic or poly-p-dicarboxylic acid plastic, which can effectively reduce the thickness of the optical sensor 110 and maintain good manufacturing yield; in addition, polyimide The plastic or poly-p-dicarboxylic acid plastic also has good thermal stability, can withstand high temperature, can withstand various process conditions in the semiconductor manufacturing process, and is beneficial to ensure the performance of the optical sensor 110. It is beneficial to better realize the integration of fingerprint recognition and image display functions, which is beneficial to the high-yield and small-thickness technical requirements. Moreover, polyimide plastic or poly-p-dicarboxylic acid plastics have better isolation performance. It can effectively prevent water vapor penetration and is beneficial to the improvement of the stability of the display module.

The device layer 112 is used together with the flexible plastic substrate 111 to constitute the optical sensor 110. The device layer 112 has a photosensitive device for collecting the reflected light to obtain a fingerprint image.

It should be noted that, in the embodiment, the optical sensor 110 is an optical film based on an amorphous silicon thin film transistor (a-Si: H TFT). The sensor, that is, the device layer 112 is a device layer based on an amorphous silicon thin film transistor. However, in other embodiments of the present invention, the optical sensor may also be an optical sensor based on a Low Temperature Polysilicon Thin Film Transistor (LTP-Si TFT) or an Indium Gallium Zinc Oxide (Indium Gallium Zinc Oxide). The optical sensor of the Thin Film Transistor, IGZO TFT), that is, the device layer may also be a device layer based on a low temperature polysilicon thin film transistor or an indium gallium zinc oxide thin film transistor.

The device layer 112 includes: a photosensitive device 113 on the flexible plastic substrate 111; and a protective layer 114 covering the photosensitive device 113 and at least a portion of the substrate 110.

In this embodiment, the optical sensor 110 includes photosensitive pixels, and the photosensitive device 113 in each of the photosensitive pixels is an amorphous silicon PIN photodiode, that is, the photosensitive device 113 in the device layer 112 of each photosensitive pixel is Amorphous silicon PIN photodiode.

In this embodiment, since the flexible plastic substrate 111 is made of a plastic material, the material of the protective layer 114 is one or two of amorphous silicon oxide and amorphous silicon nitride.

The self-luminous display panel 120 is used to implement an image display function.

In this embodiment, the self-luminous display panel 120 includes a first transparent substrate (not shown), a second transparent substrate (not shown), and a self-illuminating circuit layer (not shown). The self-illuminating circuit layer is located between the first transparent substrate and the second transparent substrate.

The self-luminous display panel 120 includes a plurality of light emitting units (not shown). Each of the light emitting units includes a light transmitting region and a non-light transmitting region, so the reflected light 132 can be transmitted through the self-luminous display panel 120.

It should be noted that the area of the light transmissive area accounts for 5% to 20% of the area of the light emitting unit. The ratio of the area of the light-transmitting area to the area of the light-emitting unit is not too high or too low. If the ratio of the area of the light-transmitting area to the area of the light-emitting unit is too low, the transmission of the reflected light 132 by the self-luminous display panel 120 may be affected, which may affect the acquisition of a clear fingerprint image; If the ratio of the area of the light area to the area of the light emitting unit is too high, the image display function of the self-luminous display panel 120 may be affected.

Specifically, the self-luminous display panel 120 may be an OLED display panel. Therefore, the display pixel unit of the self-luminous circuit layer 120 may include an anode layer, a hole injection layer (HIL), an emission layer (EML), an electron injection layer (EIL), and a cathode layer, and may also have a hole transport layer. (HTL) and an electron transport layer (ETL) may also include a structure for driving a TFT of an OLED, a driving metal line, and a storage capacitor. The specific technical solution of the self-luminous display panel 120 is the same as that of the prior art, and the present invention is not described herein again.

It should be noted that, in this embodiment, the display module further includes: a signal readout chip 160, and the signal readout chip 160 is connected to the optical sensor 110 through the flexible circuit board 170. Specifically, the signal readout chip 160 is fixed to one end of the flexible circuit board 170, and the other end of the flexible circuit board 170 is connected to the flexible plastic substrate 111 through an anisotropic conductive film 150.

The point source 130 is used to generate a light 131 that captures a fingerprint image.

The point light source 130 is located on one side of the self-luminous display panel 120 and the optical sensor 110, and the generated light 131 is obliquely projected onto the sensing surface 141 to form reflected light 132 carrying fingerprint information. .

Since the light source 131 generated by the point light source 130 has strong consistency, the stray light is less; and the point light source 130 is located on one side of the self-luminous display panel 120 and the optical sensor 110, the point The light 131 generated by the light source 130 is directly transmitted to the sensing surface 141 without transmitting the self-luminous display panel 120 and the optical sensor 110. Therefore, the probability that the light 131 generated by the point light source 130 is scattered is relatively high. Less, less stray light is formed, which can effectively reduce the scattering of the reflected light 132 formed, improve the signal-to-noise ratio of the reflected light 132, thereby improving the quality of the obtained fingerprint image, and is beneficial to the display module. Integrated fingerprint recognition and image display capabilities.

In addition, compared with the technical solution of fingerprint recognition by using the light generated by the self-luminous display panel, the use of the point light source 130 can also eliminate the use of the light collimation structure, and better reduce the display mode. The purpose of the group thickness.

In this embodiment, the point light source 130 is an infrared light source. Specifically, according to the type and technical parameters of the optical sensor 110, the point light source 130 is a near-infrared light source. The method of setting the point light source 130 as an infrared light source can effectively reduce the influence of the light 131 generated by the point light source 130 on the image display function of the self-luminous display panel 120, and can ensure the display effect. Obtaining a clear fingerprint image is beneficial to better integration of fingerprint recognition and image display functions.

Specifically, since the visible spectrum that can be perceived by human vision is in the range of 390 nm to 780 nm, the wavelength of light formed by the self-luminous display panel 120 for image display is generally in the range of 400 nm to 700 nm, so the point light source 130 The wavelength of the generated light 131 ranges from 700 nm to 1500 nm.

In this embodiment, the point light source 130 is an LED lamp; specifically, an infrared LED lamp.

The protective cover 140 is located on the point light source 130 and the self-luminous display panel 120 to provide a protection function.

The surface of the protective cover 140 facing away from the point light source 130 is the sensing surface 141 for accepting a touch for fingerprint collection. Specifically, in this embodiment, the protection The cover plate 140 is a cover glass of the self-luminous display panel 120.

The light 131 generated by the point light source 130 is transmitted through the protective cover 140, obliquely projected onto the sensing surface 141, and reflected or refracted on the sensing surface 141 to form a fingerprint. The reflected light 132 of the information is folded back into the protective cover 140, transmitted through the protective cover 140, and transmitted through the self-luminous display panel 120, projected onto the optical sensor 110, The optical sensor 110 acquires a fingerprint image.

It should be noted that, in this embodiment, the display module further includes: a filter layer 150 between the self-luminous display panel 120 and the optical sensor 110. Therefore, the reflected light 132 needs to be transmitted through the filter layer 150 to be collected by the optical sensor 110.

The filter layer 150 is used to filter out stray light to improve the quality of the obtained fingerprint image.

It can be seen from the function of the filter layer 150 that the transmittance of the filter layer 150 to stray light is preferably as low as possible; in this embodiment, the stray light is mainly visible light, so the filter layer 150 is opposite to the filter layer 150. The higher the absorption rate of visible light, the better; in addition, the point light source 130 is an infrared light source. Specifically, the reflected light 132 is near-infrared light, so according to the imaging principle of the optical sensor 110, the filtering The higher the transmittance of layer 150 to near-infrared light, the better.

In this embodiment, the transmittance of the filter layer 150 to near-infrared light is greater than 50%; and the absorption ratio of the filter layer 150 to visible light is greater than 50%. Therefore, the filter layer 150 can ensure that the stray light is removed as much as possible, and the noise signal caused by the stray light is suppressed. The transmittance of the near-infrared light can be effectively ensured, and the fingerprint image can be smoothly obtained. Therefore, the filter layer 150 is ensured. The setting can effectively improve the signal-to-noise ratio of the signal collected by the optical sensor 110, and is advantageous for obtaining a high-quality fingerprint image.

The filter layer 150 is disposed under the self-luminous display panel 120 and located between the self-luminous display panel 120 and the optical sensor 110, so the self-luminous display The light generated by the panel 120 need not be transmitted through the filter layer 150, so that the filter layer 150 can be effectively prevented from being self-luminous. The influence of the image display function of the display panel 120 can improve the quality of the fingerprint image under the premise of ensuring the image display function, thereby better integrating the fingerprint recognition and the image display function.

In this embodiment, the filter layer 150 is a multilayer dielectric reflective layer, and the stray light of a specific wavelength is filtered by the interference principle of light waves.

The filter layer 150 includes a silicon oxide layer and a titanium oxide layer which are alternately disposed. When the light is irradiated to the filter layer 150, reflection and transmission occur at the respective interfaces of the silicon oxide layer and the titanium oxide layer, and constructive interference may occur between the reflected light and the incident light. , thereby increasing the intensity of the reflected light, causing more energy to be reflected by the filter layer 150, thereby reducing the transmittance of the transmitted light; or, the reflected light and the incident light may also be cancelled. Interference, thereby reducing the intensity of the reflected light, allowing more energy to pass through the filter layer 150, thereby increasing the transmission of transmitted light.

The wavelength of the light, the thickness of the silicon oxide layer, and the thickness of the titanium oxide layer determine whether constructive interference or destructive interference occurs between the reflected light rays; therefore, the thickness of the silicon oxide layer and the thickness of the titanium oxide layer are set. , which makes the light reflectance in a specific wavelength range higher and the transmittance lower; the light transmittance in a specific wavelength range is higher, and the reflectance is lower; thereby enabling the filter layer to filter out a specific wavelength range Light.

The light is reflected at the interface between the silicon oxide layer and the titanium oxide layer, so the sum of the number of layers of the silicon oxide layer and the number of layers of the titanium oxide layer in the filter layer 150 is 5 to 60 Within the scope. The number of layers of the silicon oxide layer and the number of layers of the titanium oxide layer in the filter layer 150 may be too small, which may affect the filtering effect of the filter layer 150 on ambient light, and is not conducive to providing a fingerprint image. The quality of the silicon oxide layer in the filter layer 150 and the number of layers of the titanium oxide layer are too large, which increases the manufacturing process difficulty, increases the manufacturing cost, and reduces the yield.

In addition, in this embodiment, the filter layer 150 has a thickness of less than 5 μm. The overall thickness of the filter layer 150 is not too large. If the overall thickness of the filter layer 150 is too large (for example, greater than 10 um), the manufacturing time will increase and the cost will increase. In addition, the overall thickness is too large, and the overall film stress is too large, so that the film layer will crack and fall off.

In this embodiment, the filter layer 150 is a multi-layer dielectric reflective layer in which a silicon oxide layer and a titanium oxide layer are alternately disposed; therefore, the filter layer 150 may form the filter layer by sputtering or evaporation. 150.

In other embodiments of the invention, the filter layer is an ink layer, and the filter layer can be formed by screen printing. When the filter layer is an ink layer, the filter layer has a thickness of less than 20 μm. The thickness of the filter layer is not too large. If the thickness of the filter layer is too large, the overall thickness of the formed display module may be affected, which is disadvantageous for reducing the thickness of the formed display module.

Although the present invention has been disclosed above, the present invention is not limited thereto. Any changes and modifications may be made by those skilled in the art without departing from the spirit and scope of the invention, and the scope of the invention should be determined by the scope defined by the appended claims.

Claims

A display module, comprising:

An optical sensor comprising a flexible plastic substrate and a device layer on the flexible plastic substrate;

a self-luminous display panel located above the optical sensor;

a point light source on a side of the self-luminous display panel and the optical sensor;

a protective cover plate located above the point light source and the self-luminous display panel;

The surface of the protective cover facing away from the self-luminous display panel is a sensing surface, and the light generated by the point light source is obliquely projected to the protective cover and transmitted to the sensing surface, Reflected light carrying fingerprint information is formed on the sensing surface; the optical sensor is configured to collect the reflected light to obtain a fingerprint image.
The display module as claimed in claim 1 , wherein the flexible plastic substrate is made of polyimide plastic or polyphthalic plastic.
The display module according to claim 1, wherein the flexible plastic substrate has a thickness of less than or equal to 0.2 mm.
The display module according to claim 1, wherein the optical sensor is an optical sensor based on an amorphous silicon thin film transistor, an optical sensor based on a low temperature polysilicon thin film transistor, or an optical sensor based on an indium gallium zinc oxide thin film transistor. .
The display module according to claim 1, wherein the optical sensor comprises photosensitive pixels, and the photosensitive device in each of the photosensitive pixels is an amorphous silicon PIN photodiode.
The display module of claim 1 , wherein the self-luminous display panel is an OLED display panel.
The display module of claim 1 , wherein the self-illuminating panel comprises a plurality of light emitting units, the light emitting unit comprises a light transmissive area, and the area of the light transmissive area accounts for 5% of the area of the light emitting unit To 20%.
The display module of claim 1 wherein said point source is an infrared source.
The display module of claim 1 further comprising: a filter layer between the self-luminous display panel and the optical sensor.
The display module according to claim 9, wherein the filter layer has a transmittance to infrared light of more than 50%.
The display module according to claim 9, wherein the filter layer absorbs visible light by more than 50%.
The display module according to claim 9, 10 or 11, wherein the filter layer is an ink layer or a multilayer dielectric reflective layer.
The display module according to claim 12, wherein the filter layer is an ink layer;

The filter layer is formed by screen printing.
The display module according to claim 12, wherein the filter layer is an ink layer;

The filter layer has a thickness of less than 20 μm.
The display module according to claim 12, wherein the filter layer is a multilayer dielectric reflective layer;

The filter layer is formed by sputtering or evaporation.
The display module according to claim 12, wherein the filter layer is a multilayer dielectric reflective layer;

The filter layer has a thickness of less than 5 μm.