Display panel and display device

A display panel and a display device thereof are provided. The display panel comprises a display module comprising a first substrate and a first polarizer, wherein a light-exiting surface of the display module is arranged on an outer side of the first polarizer; a fingerprint recognition module disposed on an outer side of the first substrate and comprising a fingerprint recognition layer and a second polarizer disposed on an inner side of the fingerprint recognition layer; and a light source disposed on an inner side of the first polarizer. The fingerprint recognition layer recognizes fingerprint based on fingerprint signal light. The first polarizer is engaged with the second polarizer, such that the fingerprint signal light is transmitted through the first polarizer and the second polarizer without a light intensity loss, and the second polarizer reduces the light intensity of fingerprint noise light.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims the priority of Chinese Patent Application No. CN201710289239.9, filed on Apr. 27, 2017, the entire contents of which are incorporated herein by reference.

FIELD OF THE DISCLOSURE

The present disclosure generally relates to the display technology and, more particularly, relates to a display panel and a display device thereof.

BACKGROUND

A fingerprint is a mark made by the pattern of ridges on the pad of a human finger, which is innate and unique for everyone. With the development of science and technology, a variety of display devices with a fingerprint recognition function are emerging on the market, such as mobile phones, tablets and smart wearable devices, etc. To operate a display device with the fingerprint recognition function, a user can verify the permission only by touching the fingerprint recognition sensor of the display device, thereby simplifying the permission verification.

In an existing display device with the fingerprint recognition function, the fingerprint recognition sensor is often provided in a non-display region of the display panel or on a surface opposite to the light exiting side of the display device. In such an existing display device, the user has to specifically touch the fingerprint recognition sensor to verify the permission, degrading the user experience. In addition, when the fingerprint recognition sensor is disposed in the non-display region of the display panel, the screen-to-body ratio of the display panel is reduced, which is not in line with the development trend of narrow borders in the display panel.

Given the gate, source and drain electrodes of the thin-film-transistor (TFT) in the pixel circuit which is arranged in the display region of the display panel are often made of metal, when the fingerprint recognition sensor is directly disposed in the display region of the display panel, light emitted from the light source of the fingerprint recognition sensor may be directly reflected by the gate, source and drain electrodes of the TFT, and then incident onto the fingerprint recognition sensor, generating noises and degrading the accuracy of the fingerprint recognition sensor. In addition, the light that is leaked from the organic light-emitting layer of the display panel may also be incident onto the fingerprint recognition sensor, generating noises and degrading the accuracy of the fingerprint recognition sensor.

The disclosed display panel and display device thereof are directed to solve one or more problems set forth above and other problems.

BRIEF SUMMARY OF THE DISCLOSURE

One aspect of the present disclosure provides a display panel. The display panel comprises a display module comprising a first substrate and a first polarizer disposed on the first substrate, wherein the first substrate has an inner side facing the first polarizer and an opposite outer side, the first polarizer has an inner side facing the first substrate and an opposite outer side, and a light-exiting surface of the display module is arranged on the outer side of the first polarizer; a fingerprint recognition module disposed on the outer side of the first substrate and comprising a fingerprint recognition layer and a second polarizer, wherein the fingerprint recognition layer has an inner side facing the display module and an opposite outer side, and the second polarizer is disposed on the inner side of the fingerprint recognition layer; and a light source disposed on the inner side of the first polarizer. The fingerprint recognition layer is configured to recognize fingerprint based on fingerprint signal light, the fingerprint signal light being light emitted from the light source and then reflected to the fingerprint recognition layer by a touch object, the first polarizer is engaged with the second polarizer, such that the fingerprint signal light is transmitted through the first polarizer and the second polarizer without a light intensity loss, and the second polarizer is configured to reduce the light intensity of fingerprint noise light, the fingerprint noise light being light other than the fingerprint signal light.

Another aspect of the present disclosure provides a display device comprising a display panel. The display panel comprises a display module comprising a first substrate and a first polarizer disposed on the first substrate, wherein the first substrate has an inner side facing the first polarizer and an opposite outer side, the first polarizer has an inner side facing the first substrate and an opposite outer side, and a light-exiting surface of the display module is arranged on the outer side of the first polarizer; a fingerprint recognition module disposed on the outer side of the first substrate and comprising a fingerprint recognition layer and a second polarizer, wherein the fingerprint recognition layer has an inner side facing the display module and an opposite outer side, and the second polarizer is disposed on the inner side of the fingerprint recognition layer; and a light source disposed on the inner side of the first polarizer. The fingerprint recognition layer is configured to recognize fingerprint based on fingerprint signal light, the fingerprint signal light being light emitted from the light source and then reflected to the fingerprint recognition layer by a touch object, the first polarizer is engaged with the second polarizer, such that the fingerprint signal light is transmitted through the first polarizer and the second polarizer without a light intensity loss, and the second polarizer is configured to reduce the light intensity of fingerprint noise light, the fingerprint noise light being light other than the fingerprint signal light.

DETAILED DESCRIPTION

Reference will now be made in detail to exemplary embodiments of the disclosure, which are illustrated in the accompanying drawings. Hereinafter, embodiments consistent with the disclosure will be described with reference to drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. It is apparent that the described embodiments are some but not all of the embodiments of the present disclosure. Based on the disclosed embodiments, persons of ordinary skill in the art may derive other embodiments consistent with the present disclosure, all of which are within the scope of the present disclosure. Further, in the present disclosure, the disclosed embodiments and the features of the disclosed embodiments may be combined under conditions without conflicts.

As discussed in the background, a fingerprint is a mark made by the pattern of ridges on the pad of a human finger, which is innate and unique for everyone. Thus, we can put a person with his fingerprints, by comparing his fingerprints and pre-stored fingerprint data to verify his true identity, which is called as fingerprint recognition technology. The analysis of fingerprints for matching purposes generally requires the comparison of several features of the print pattern. These include patterns, which are aggregate characteristics of ridges, and minutia points, which are unique features found within the patterns.

Thanks to the electronic integration manufacturing technology, as well as the reliable algorithm research, optical fingerprint recognition technology is emerging in our daily life, which has been the most deeply-researched, the most widely used, and the most mature technology in biological detection technology. The principle of optical fingerprint recognition technology is explained as follows. The light source in the display panel emits light to a user finger, and the light reflected by the user finger is incident onto a fingerprint sensor, and corresponding light signals are collected by the fingerprint sensor. Due to the specific lines on the fingerprint, the light reflected at different positions of the user finger has different light intensity, and then the fingerprint sensor collects different light signals, according to which the user's true identity is determined.

The present disclosure provides an improved display panel and display device, which is able to reduce the noise signal in the fingerprint recognition module, and improve the accuracy of the fingerprint recognition.

The display panel comprises:a display module comprising a first substrate and a first polarizer disposed on the first substrate, wherein the first substrate has an inner side facing the first polarizer and an opposite outer side, the first polarizer has an inner side facing the first substrate and an opposite outer side, and a light-exiting surface of the display module is arranged on the outer side of the first polarizer;a fingerprint recognition module disposed on the outer side of the first substrate and comprising a fingerprint recognition layer and a second polarizer, wherein the fingerprint recognition layer has an inner side facing the display module and an opposite outer side, and the second polarizer is disposed on the inner side of the fingerprint recognition layer; anda light source disposed on the inner side of the first polarizer,wherein the fingerprint recognition layer is configured to recognize fingerprint based on fingerprint signal light, the fingerprint signal light being light emitted from the light source and then reflected to the fingerprint recognition layer by a touch object,the first polarizer is engaged with the second polarizer, such that the fingerprint signal light is transmitted through the first polarizer and the second polarizer without a light intensity loss, andthe second polarizer is configured to reduce the light intensity of fingerprint noise light, the fingerprint noise light being light other than the fingerprint signal light.

In the disclosed embodiments, the light-exiting surface of the display module is disposed on the outer side of the first polarizer, the fingerprint recognition module is disposed on the outer side of the first substrate, the fingerprint recognition module comprises the fingerprint recognition layer and the second polarizer disposed on the inner side of the fingerprint recognition layer. At the fingerprint recognition stage, the light emitted from the inner side of the first polarizer is reflected by the touch object (such as a user finger) to form the fingerprint signa light, during which the first polarizer is engaged with the second polarizer, such that the fingerprint signal light is transmitted through the first polarizer and the second polarizer without a light intensity loss.

Meanwhile, before the light (i.e., the fingerprint noise light) which is not reflected by the touch object is incident onto the fingerprint recognition layer, the second polarizer at least reduces the light intensity of the fingerprint noise light. Thus, the crosstalk caused by the fingerprint noise may be suppressed, the signal-to-noise ratio may be improved, and the accuracy of the fingerprint recognition module may be improved.

In one embodiment, the light source may be an existing light source in the display panel, such that the thickness of the display panel may not be increased, the fabrication process may be simplified, and the fabrication cost may be reduced. In another embodiment, the fingerprint recognition module has an inner side facing the display module and an opposite outer side, and an external source may be disposed on the outer side of the fingerprint recognition module and configured as the light source. Thus, the position of the light source (for example, the distance between the light source and the fingerprint recognition layer) may be adjusted, and the light source with the desired lighting properties may be selected (for example, a highly collimated light source may be selected to reduce the interference between the fingerprint signal light). The light source is not limited by the present disclosure, as long as the light source is disposed on the inner side of the first polarizer and the fingerprint recognition module can detect the fingerprint signal light.

The fingerprint noise light may include part of the light leaked out from the light source of the display module to the fingerprint recognition module, and/or the light emitted from the external light source and then reflected by the metals (e.g., gate, source, drain electrodes of a thin-film-transistors) in the display module.

For the part of the light leaked out from the light source of the display module to the fingerprint recognition module, the second polarizer may be configured to be a linear polarizer or a circular polarizer, which is able to reduce the light intensity of the fingerprint noise light by half. For the light emitted from the external light source and then reflected by the metals (e.g., gate, source, drain electrodes of a thin-film-transistors) in the display module, the second polarizer may be configured to be a circular polarizer, which is able to completely eliminate the fingerprint noise light.

In one embodiment, when second polarizer is a linear polarizer, the first polarizer may be configured to have the same polarization direction as the second polarizer, such that the fingerprint signal light is transmitted through the first polarizer and the second polarizer without a light intensity loss. In another embodiment, when second polarizer is a circular polarizer, the first polarizer may be configured to be a circular polarizer which is engaged with the second polarizer, such that the fingerprint signal light is transmitted through the first polarizer and the second polarizer without a light intensity loss.

FIG. 1illustrates a schematic cross-sectional view of an exemplary display panel consistent with disclosed embodiments. As shown inFIG. 1, the display panel may comprise a display module1and a fingerprint recognition module2. The display module1may comprise a first substrate10and a first polarizer11disposed on the first substrate10. The first polarizer11may have an inner side facing the first substrate10and an opposite outer side. The light-exiting surface of the display module1may be disposed on the outer side of the first polarizer11.

The first substrate10may have an inner side facing the first polarizer11and an opposite outer side. The fingerprint recognition module2may be disposed on the outer side of the first substrate10. The fingerprint recognition module2may comprise a fingerprint recognition layer21and a second polarizer22. The fingerprint recognition layer21may have an inner side facing the display module1and an opposite outer side, and the second polarizer22may disposed on the inner side of the fingerprint recognition layer21. The fingerprint recognition layer21may be configured to identify the fingerprint based on fingerprint signal light, which is emitted from a light source and then reflected to the fingerprint recognition layer21by a touch object.

The display module1may further comprise an organic light-emitting layer12disposed between the first substrate10and the first polarizer11for generating light for displaying an image. The display module1may also comprise any other appropriate components, which is not limited by the present disclosure.

In one embodiment, the organic light-emitting layer12may comprise a plurality of organic light-emitting units. For example, as shown inFIG. 1, the organic light-emitting layer12may comprise a red organic light-emitting unit121, a green organic light-emitting unit122, and a blue organic light-emitting unit123. The fingerprint recognition layer21may comprise a plurality of fingerprint recognition units211.

In one embodiment, the organic light-emitting layer12may be multiplexed as the light source for fingerprint recognition. For example, a plurality of organic light-emitting units and a plurality of fingerprint recognition units may be arranged in an array, respectively. The plurality of organic light-emitting units may be arranged in correspondence with the plurality of fingerprint recognition units. When the organic light-emitting unit is multiplexed as the light source, the light emitted from one organic light-emitting unit may be received by one or more fingerprint recognition units corresponding to the organic light-emitting unit.

In one embodiment, the display panel may include a display region, where the organic light-emitting unit and the fingerprint recognition unit are disposed. Thus, the fingerprint recognition may be realized in the display region of the display panel.

Referring toFIG. 1, the light emitted from the organic light-emitting layer12may be incident onto the touch object, which is often a user finger. The fingerprint is composed of a series of ridges41and valleys42disposed on the skin surface of the fingertip. The light, which is received by the fingerprint recognition unit42after being respectively reflected by the ridges41and the valley42, may be different in light intensity. Then the current signals converted from the light intensity of the light respectively reflected by the ridges41and the valley42may be different in magnitude, based on which fingerprint may be recognized.

It should be noted that, the touch object may also be a palm, and the fingerprint recognition unit may realize the detection and recognition functions based on the palmprint.

When the organic light-emitting layer12functions as a light source for both image display and fingerprint recognition, the organic light-emitting layer12has to emit light at both the display stage and the fingerprint recognition stage. In one embodiment, at the display stage, all the organic light-emitting units in the organic light-emitting layer may be provided with a driving signal for light emission, while at the fingerprint recognition stage, a part of the organic light-emitting units in the organic light-emitting layer may be provided with a driving signal for light emission. Accordingly, the display module1may further include a first display driving circuit19, which may output a driving signal for driving at least one of the organic light-emitting units to emit light at the fingerprint recognition stage, thereby providing a light source to the fingerprint recognition module2.

Because the light emitted by the blue organic light-emitting unit often has short wavelength while respective layers (e.g., organic insulating layers, inorganic insulating layers, polarizers, etc.) in the display panel strongly absorb the light of short wavelength, the light emitted by the blue organic light-emitting unit has lower light transmittance and is easily to be absorbed by the display panel. In addition, the material of the light-emitting functional layer of the blue organic light-emitting unit may have a shorter lifetime than the materials of the light-emitting function layer in the red organic light-emitting unit and green organic light-emitting unit. Thus, at the fingerprint recognition stage, the first display driving circuit19may output a driving signal for driving at least one of the red organic light-emitting unit and the green organic light-emitting unit to emit light.

In one embodiment, the display panel may include a touch function layer, where the structure and the position of the touch function layer are not limited by the present disclosure as long as the touch position on the screen can be detected. When the finger touch position on the screen is detected, during the fingerprint recognition stage, the first display driving circuit19may output a driving signal to drive the organic light-emitting units in the region corresponding to the finger touch position to emit light.

In one embodiment, the first polarizer11may comprise a first linear polarizer, and the second polarizer22may comprise a second linear polarizer. The first and second polarizers may have the same polarization direction, i.e., the optical axes of the first and second polarizers may be arranged in the same direction.

Referring toFIG. 1, the solid arrows indicate the light emitted from the organic light-emitting layer12toward the light exiting surface and the light reflected by the touch object to form the fingerprint signal light. The dashed arrow indicates the light that is leaked out from the organic light-emitting layer12to the fingerprint recognition module2

On one hand, the light emitted from the organic light-emitting layer, such as the red organic light-emitting unit121inFIG. 1, may be converted into linearly polarized light by the first polarizer11. After being incident onto and reflected by the touch object, the reflected light which is the fingerprint signal light may still be linearly polarized light, and the polarization direction is not changed. The fingerprint signal light may be transmitted through the first polarizer11without a light loss. Because the first and second polarizers have the same polarization direction, the fingerprint signal light may also be transmitted through the second polarizer22without a light loss, and then incident onto the fingerprint recognition unit211

On the other hand, the light leaked out from the red organic light-emitting unit121is substantially uniform in the respective polarization directions. After being transmitted through the second polarizer22, the transmitted light has only one polarization direction, and the light intensity thereof is approximately reduced by half. Thus, when upon being incident onto the fingerprint recognition unit211, the light leaked out from the organic light-emitting unit may have significantly reduced light intensity.

In summary, the light intensity of the fingerprint noise light is relatively reduced while the light intensity of the fingerprint light is substantially the same. Thus, the signal-to-noise ratio of the fingerprint recognition module2may be improved, thereby improving the accuracy of the fingerprint recognition module2.

In one embodiment, the display panel may be a rigid display panel. For example, as shown inFIG. 1, the first substrate10may be a first glass substrate. The display module1may further include a second glass substrate13, and the organic light-emitting layer12may be disposed between the first glass substrate10and the second glass substrate13. The first glass substrate10and the second glass substrate13may be supported by spacers15, and an air gap may be formed between the first glass substrate10and the second glass substrate13. In certain embodiments, the thickness of the air gap may be approximately 4 μm.

The display panel may also include a cover glass or cover lens14. The first polarizer11may have an inner side facing the organic light-emitting layer12and an opposite outer side. The cover glass14may be attached to the outer side of the first polarizer11by liquid optical clear adhesive (LOCA). In certain embodiments, the thickness of the display module1may be approximately 1410 μm.

Further, the fingerprint recognition module2may further include a second substrate20having an inner side facing the display module1and an opposite outer side. The fingerprint recognition layer21may be disposed on the inner side of the second substrate20. That is, the fingerprint recognition layer21may be directly fabricated on the inner side of the second substrate20, simplifying the arrangement of the fingerprint recognition layer21. Meanwhile, the second substrate20may also protect the fingerprint recognition layer21. In addition, the second polarizer22may be attached to the first substrate10through a liquid optical clear adhesive (LOCA) (not drawn inFIG. 1), through which the display module1and the fingerprint recognition module2may be attached to each other to form the display panel.

In one embodiment, the first polarizer11may include a first quarter-wave plate and a third linear polarizer stacked together. The third linear polarizer may have an inner side facing the organic light-emitting layer12and an opposite outer side, and the first quarter-wave plate may be disposed on the inner side of the third linear polarizer. The second polarizer22may include a second quarter-wave plate and a fourth linear polarizer stacked together. The fourth linear polarizer may have an inner side facing the organic light-emitting layer12and an opposite outer side, and the second quarter-wave plate may be disposed on the inner side of the fourth linear polarizer. The first quarter-wave plate and the second quarter-wave plate may have the same material and the same thickness.

In the disclosed embodiments, when facing the propagation direction of the light, counterclockwise is defined as the positive direction.

In one embodiment, the angle from the optical axis of the first quarter-wave plate to the polarization direction of the third linear polarizer may be configured to be approximately 45°. The angle from the optical axis of the second quarter-wave plate to the polarization direction of the fourth linear polarizer may be configured to be approximately −45°. In another embodiment, the angle from the optical axis of the first quarter-wave plate to the polarization direction of the third linear polarizer may be configured to be approximately −45°. The angle from the optical axis of the second quarter-wave plate to the polarization direction of the fourth linear polarizer may be configured to be approximately 45°. Thus, the formed first polarizer and second polarizer may both be circular polarizers.

FIG. 2aillustrates an exemplary optical path before light emitted from an organic light-emitting layer is reflected by a touch object consistent with disclosed embodiments.FIG. 2billustrates an exemplary optical path after light emitted from an organic light-emitting layer is reflected by a touch object consistent with disclosed embodiments;

InFIG. 2aandFIG. 2b, counterclockwise is defined as the positive direction when facing the propagation direction of the light. As shown inFIG. 1, the light before and after being reflected by the touch object have different propagation directions.

The first quarter-wave plate and the second quarter-wave plate may both be calcite, and the e-axis of the first quarter-wave plate and the e-axis of the second quarter-wave plate are defined as the optical axis, respectively.

Referring toFIG. 1andFIG. 2a, at the fingerprint recognition stage and before the light is reflected by the touch object, the angle from the e-axis of the first quarter-wave111plate to the polarization direction P of the third linear polarizer112may be configured to be approximately −45°. The natural light NL_1emitted from the organic light-emitting layer12may pass through the first quarter-wave plate111and become natural light NL_2which is substantially remain the same as the natural light NL_1. The NL_2may pass through the third linear polarizer112to be converted into linearly polarized light NL_3having the same polarization direction P as the third linear polarizer112. That is, the polarization direction of the converted linearly polarized light NL_3may be in the second and fourth quadrants.

Referring toFIG. 2b, the linearly polarized light NL_3inFIG. 2amay be reflected by the touch body to form the fingerprint signal light FSL_1inFIG. 2b, which is still linearly polarized light with substantially the same polarization direction (i.e., polarization direction P). However, after the linearly polarized light NL_3inFIG. 2ais reflected by the touch body, when facing the propagation direction of the fingerprint signal light, the angle from the e-axis of the first quarter-wave plate111to the polarization direction P of the third linear polarizer112now becomes 45°, and the polarization direction of the fingerprint signal light is in the first and third quadrants, as shown inFIG. 2b.

The fingerprint signal light FSL_1may be transmitted through the third linear polarizer112to become the fingerprint signal light FSL_2having substantially the same polarization state and the light intensity. The fingerprint signal light FSL_2may be transmitted through the first quarter-wave plate111to become left-handed circular polarized light FSL_3having substantially the same light intensity.

Then the left-handed circular polarized light FSL_3may be transmitted through the second quarter-wave plate221to become linearly polarized light FSL_4with a polarization direction in the second and fourth quadrants and substantially the same light intensity. Finally, the linearly polarized light FSL_4may pass through the fourth linear polarizer222having the same polarization direction as the FSL_4to become linearly polarized light FSL_5with substantially the same light intensity.

FIG. 3illustrates an exemplary optical path of fingerprint noise light emitted from an organic light-emitting layer consistent with disclosed embodiments. The fingerprint noise light FNL_1emitted from the organic light-emitting layer may be directly incident onto the second polarizer. When facing the propagation direction of the fingerprint noise light, the angle from the e-axis of the second quarter-wave plate221to the polarization direction of the fourth linear polarizer222may be configured to be approximately −45°. The polarization direction of the fourth linear polarizer222is in the second and fourth quadrants.

The fingerprint noise light FNL_1may be transmitted through the second quarter-wave plate221to become fingerprint noise light FNL_2which is still natural light. The fingerprint noise light FNL_2may pass through the fourth linear polarizer222to become linear polarized light FNL_3having a same polarization direction as the fourth linear polarizer222, and the light intensity of FNL_3is reduced to half. Thus, the second polarizer222may reduce the light intensity of the fingerprint noise light, thereby improving the signal-to-noise ratio of fingerprint recognition.

FIG. 4illustrates a schematic cross-sectional view of another exemplary display panel consistent with disclosed embodiments. The similarities betweenFIG. 1andFIG. 4are not repeated here, while certain difference may be explained.

As shown inFIG. 4, the display panel may be a flexible display panel. For example, the first substrate10may be a flexible substrate. The display module1may further comprises a thin film encapsulation layer16, which replaces the second glass substrate13inFIG. 1. The thin film encapsulation layer16may cover the organic light-emitting layer12.

FIG. 5illustrates a schematic cross-sectional view of another exemplary display panel consistent with disclosed embodiments. The similarities betweenFIG. 1andFIG. 5are not repeated here, while certain difference may be explained.

As shown inFIG. 5a, the display panel may comprise a display module1, a fingerprint recognition module2, and a backlight source3. The display module1may comprise a first substrate10, a first polarizer11disposed on the first substrate10, and an organic light-emitting layer12disposed between the first substrate10and the first polarizer11for displaying images. The first polarizer11may have an inner side facing the first substrate10and an opposite outer side. The light-exiting surface of the display module1may be disposed on the outer side of the first polarizer11.

The first substrate10may have an inner side facing the first polarizer11and an opposite outer side. The fingerprint recognition module2may be disposed on the outer side of the first substrate10. The fingerprint recognition module2may comprise a fingerprint recognition layer21and a second polarizer22. The fingerprint recognition layer21may have an inner side facing the display module1and an opposite outer side, and the second polarizer22may disposed on the inner side of the fingerprint recognition layer21. The fingerprint recognition layer21may be configured to identify the fingerprint based on the fingerprint signal light, which is emitted from a light source and then reflected to the fingerprint recognition layer21by a touch object.

The fingerprint recognition module2may have an inner side facing the display module1and an opposite outer side. The backlight source3may be disposed on the outer side of the fingerprint recognition module2. The backlight source3may be configured to be a light source for the fingerprint recognition module2.

In one embodiment, the organic light-emitting layer12may comprise a plurality of organic light-emitting units. For example, as shown inFIG. 5, the organic light-emitting layer12may comprise a red organic light-emitting unit121, a green organic light-emitting unit122, and a blue organic light-emitting unit123. The fingerprint recognition layer21may comprise a plurality of fingerprint recognition units211.

In one embodiment, the display panel may include a display region and a non-display region surrounding the display region, and the organic light-emitting unit and the fingerprint recognition unit may be disposed in the display region. Thus, the fingerprint recognition may be realized in the display region of the display panel.

The organic light-emitting layer12may emit light for displaying images, while the backlight source3may be configured as a light source for the fingerprint recognition module2. That is, at the display stage, the backlight source3may not emit light while the organic light-emitting layer12may emit light, such that the image display may not be affected. At the fingerprint recognition stage, the organic light-emitting layer12may not emit light while the backlight source3may emit light, such that the interference on the fingerprint recognition, which is caused by the light leaked out from the organic light-emitting layer12as well as the light reflected by the touch object to the fingerprint recognition unit121, may be suppressed.

Accordingly, the display module1inFIG. 5may further comprise a second display driving circuit18, which may not output a display driving signal for driving the organic light-emitting layer to emit light at the fingerprint recognition stage, and not output a detection driving signal for driving the backlight source to emit light at the display stage.

In one embodiment, the first polarizer11may include a first quarter-wave plate and a third linear polarizer stacked together. The third linear polarizer may have an inner side facing the organic light-emitting layer12and an opposite outer side, and the first quarter-wave plate may be disposed on the inner side of the third linear polarizer. The second polarizer22may include a second quarter-wave plate and a fourth linear polarizer stacked together. The fourth linear polarizer may have an inner side facing the organic light-emitting layer12and an opposite outer side, and the second quarter-wave plate may be disposed on the inner side of the fourth linear polarizer. The first quarter-wave plate and the second quarter-wave plate may have the same material and the same thickness.

Counterclockwise is defined as the positive direction when facing the propagation direction of the fingerprint signal light. In one embodiment, the angle from the optical axis of the first quarter-wave plate to the polarization direction of the third linear polarizer may be configured to be approximately 45°. The angle from the optical axis of the second quarter-wave plate to the polarization direction of the fourth linear polarizer may be configured to be approximately −45°. In another embodiment, the angle from the optical axis of the first quarter-wave plate to the polarization direction of the third linear polarizer may be configured to be approximately −45°. The angle from the optical axis of the second quarter-wave plate to the polarization direction of the fourth linear polarizer may be configured to be approximately 45°. Thus, the formed first polarizer and second polarizer may both be circular polarizers.

FIG. 6aillustrates another exemplary optical path before light emitted from a light source is reflected by a touch object consistent with disclosed embodiments.FIG. 6billustrates another exemplary optical path after light emitted from a light source is reflected by a touch object consistent with disclosed embodiments.

InFIG. 6aandFIG. 6b, counterclockwise is defined as the positive direction when facing the propagation direction of the fingerprint signal light. The first quarter-wave plate and the second quarter-wave plate may both be calcite, and the e-axis of the first quarter-wave plate and the e-axis of the second quarter-wave plate is defined as the optical axis, respectively.

Referring toFIG. 5, the light before and after being reflected by the touch object have different propagation directions. The solid arrows indicate the light emitted from the backlight source3toward the light exiting surface, as well as, the light reflected by the touch object to form the fingerprint signal light. The dashed arrow indicates the light that is leaked out from the backlight source3to the fingerprint recognition module2

Referring toFIG. 5andFIG. 6a, at the fingerprint recognition stage and before the light emitted from the backlight source3is reflected by the touch object, the angle from the e-axis of the first quarter-wave plate111to the polarization direction P of the third linear polarizer112may be configured to be approximately −45°. The angle from the e-axis of the second quarter-wave plate221to the polarization direction P of the fourth linear polarizer222may be configured to be approximately 45°.

The natural light NL_1emitted from the backlight source3may pass through the fourth linear polarizer222, and become linearly polarized light NL_2with a polarization direction in the first and third quadrants. The linearly polarized light NL_2with the polarization direction in the first and third quadrants may pass through the second quarter-wave plate221, and become left-handed circular polarized light NL_3. The left-handed circular polarized light NL_3may pass through the first quarter-wave plate111, and become linearly polarized light NL_4with a polarization direction in the second and fourth quadrants, which is the same as the polarization direction P of the third linear polarizer112. Finally, the linearly polarized light NL_4with the polarization direction in the second and fourth quadrants may pass through the third linear polarizer112to become linearly polarized light NL_5without a polarization direction change, i.e., the linearly polarized light NL_5with the same polarization as the third linear polarizer112may be incident onto the touch object.

Referring toFIG. 5andFIG. 6b, at the fingerprint recognition stage and after the light emitted from the backlight source3is reflected by the touch object, now the angle from the e-axis of the first quarter-wave plate111to the polarization direction P of the third linear polarizer112may be configured to be approximately 45°. The angle from the e-axis of the second quarter-wave plate221to the polarization direction P of the fourth linear polarizer222may be configured to be approximately −45°.

As discussed inFIG. 6a, the linearly polarized light NL_5inFIG. 6amay be incident onto the touch object. The linearly polarized light NL_5may be reflected by the touch object to become the linearly polarized fingerprint signal light FSL_1inFIG. 6bwithout a polarization direction change. Facing the prorogation direction of the fingerprint signal light FSL_1, the polarization direction of the linearly polarized fingerprint signal light FSL_1may be in the first and third quadrants. The linearly polarized fingerprint signal light FSL_1may pass through the third linear polarizer112and become the linearly polarized fingerprint signal light FSL_2with substantially the same polarization direction and light intensity.

The linearly polarized fingerprint signal light FSL_2may pass through the first quarter-wave plate111and become left-handed circular polarized fingerprint signal light FSL_3with substantially the same light intensity. The left-handed circular polarized fingerprint signal light FSL_3may pass through the second quarter-wave plate221and become linearly polarized fingerprint signal light FSL_4with a polarization direction in the second and fourth quadrants and with substantially the same light intensity. The linearly polarized fingerprint signal light FSL_4may pass through the fourth linear polarizer222having a same polarization direction as the linearly polarized fingerprint signal light FSL_4and become the linearly polarized fingerprint signal light FSL_5with substantially the same light intensity.

FIG. 7aillustrates an exemplary optical path before fingerprint noise light emitted from a backlight source is reflected by a touch object consistent with disclosed embodiments.FIG. 7billustrates an exemplary optical path after fingerprint noise light emitted from a backlight source is reflected by a touch object consistent with disclosed embodiments. InFIG. 7aandFIG. 7b, counterclockwise is defined as the positive direction when facing the propagation direction of the light.

Referring toFIG. 5andFIG. 7a, when facing the propagation direction of the fingerprint signal light, the angle from the e-axis of the second quarter-wave plate221to the polarization direction P of the fourth linear polarizer222may be configured to be approximately 45°. The natural light NL_1emitted from the backlight source3may pass through the fourth linear polarizer222and become linearly polarized light NL_2with a polarization direction in the first and third quadrants. The linearly polarized light NL_2with a polarization direction in the first and third quadrants may pass through the second quarter-wave plate221and become left-handed circular polarized light NL_3.

Then the left-handed circular polarized light NL_3may be incident onto a metal layer (e.g., an electrode in the organic light-emitting layer12inFIG. 5), then reflected by the metal layer, becoming right-handed circular polarized fingerprint noise light FNL_1inFIG. 7b.

Referring toFIG. 5andFIG. 7b, when facing the propagation direction of the fingerprint noise light, the angle from the e-axis of the second quarter-wave plate221to the polarization direction P of the fourth linear polarizer222may be configured to be approximately −45°. The right-handed circular polarized fingerprint noise light FNL_1may pass through the second quarter-wave plate221and become linearly polarized light FNL_2with a polarization direction in the first and third quadrants. In particular, the polarization direction of the linearly polarized light FNL_2may be perpendicular to the polarization direction P of the fourth linear polarizer222. Thus, the linearly polarized light FNL_2may not pass through the fourth linear polarizer222to be incident onto the fingerprint recognition units211. Accordingly, the fourth linear polarizer222may be able to eliminate the fingerprint noise light reflected by the metal layers in the display module1, and the signal-to-noise ratio of the fingerprint recognition may be improved.

In one embodiment, the display panel may be a rigid display panel. For example, as shown inFIG. 5, the first substrate10may be a first glass substrate. The display module1may further include a second glass substrate13, the organic light-emitting layer12may be disposed between the first glass substrate10and the second glass substrate13. The first glass substrate10and the second glass substrate13may be supported by spacers15, and an air gap may be formed between the first glass substrate10and the second glass substrate13. In certain embodiments, the thickness of the air gap may be approximately 4 μm.

The display panel may also include a cover glass or cover lens14. The first polarizer11may have an inner side facing the organic light-emitting layer12and an opposite outer side. The cover glass14may be attached to the outer side of the first polarizer11by liquid optical clear adhesive (LOCA). In certain embodiments, the thickness of the display module1may be approximately 1410 μm.

Further, in the disclosed embodiments, the fingerprint recognition module2may further include a second substrate20having an inner side facing the display module1and an opposite outer side. The fingerprint recognition layer21may be disposed on the inner side of the second substrate20. That is, the fingerprint recognition layer21may be directly fabricated on the inner side of the second substrate20, facilitating the arrangement of the fingerprint recognition layer21. Meanwhile, the second substrate20may also protect the fingerprint recognition layer21. In addition, the second polarizer22may be attached to the first substrate10through an optical adhesive layer including liquid optical clear adhesive (LOCA) (not drawn inFIG. 5), through which the display module1and the fingerprint recognition module2may be attached to each other to form the display panel.

FIG. 8illustrates a schematic cross-sectional view of another exemplary display panel consistent with disclosed embodiments. The similarities betweenFIG. 5andFIG. 8are not repeated here, while certain difference may be explained.

As shown inFIG. 8, the display panel may be a flexible display panel. In particular, the first substrate10may be a flexible substrate, and the display module1may further comprises a thin film encapsulation layer16, which replaces the second glass substrate13in

FIG. 5. The thin film encapsulation layer16may cover the organic light-emitting layer12.

It should be noted that, the optical axis direction of the quarter-wave plate and the polarization direction of the linear polarizer shown inFIGS. 2a, 6aand 6bare for illustrative purposes, and are not intended to limit the scope of the present disclosure. In the disclosed embodiments, the optical axis direction of the first quarter-wave plate and the optical axis direction of the second quarter-wave plate have no specific relationship, and the polarization direction of the third linear polarizer and the polarization direction of the fourth linear polarizer have no specific relationship, as long as the angle from the optical axis of the first quarter-wave plate to the polarization direction of the third linear polarizer, and the angle from the fourth quarter-wave plate to the polarization direction of the fourth linear polarizer satisfy the limiting conditions of the disclosed embodiments.

Further, in the disclosed embodiments, a fingerprint recognition unit may comprise a fingerprint sensor.

FIG. 9aillustrates a circuit diagram of an exemplary fingerprint sensor in an exemplary fingerprint recognition module consistent with disclosed embodiments.FIG. 9billustrates a schematic cross-sectional view of an exemplary fingerprint sensor in an exemplary fingerprint recognition module consistent with disclosed embodiments.

As shown inFIG. 9aandFIG. 9b, the fingerprint sensor may include a photodiode D, a storage capacitor C, and a thin-film-transistor (TFT) T. In particular, the photodiode D may have a positive electrode D1electrically connected to the first electrode of the storage capacitor C, and a negative electrode D2electrically connected to the second electrode of the storage capacitor C and the source electrode Ts of the thin-film-transistor T. The gate electrode Tg of the thin-film-transistor T may be electrically connected to a switch control line Gate, and the drain Td of the thin-film-transistor T may be electrically connected to a signal detection line Data. The photodiode D may convert the fingerprint signal light into a current signal. At the fingerprint recognition stage, the switch control line Gate may control the thin-film-transistor T to turn on, and the current signal may be transmitted to the signal detection line Data by the thin-film-transistor T, thereby realizing the fingerprint recognition according to the current signal.

In addition, to improve the accuracy of fingerprint recognition, the present disclosure also provides certain exemplary display panels.

For example, the present disclosure provides an exemplary display panel where the organic light-emitting layer is multiplexed as a light source for fingerprint recognition.

FIG. 10aillustrates a schematic top view of another exemplary display panel consistent with disclosed embodiments.FIG. 10billustrates a partial enlarged schematic view of an exemplary S1region inFIG. 10aconsistent with disclosed embodiments.FIG. 10cillustrates a schematic A1-A2sectional view of another exemplary display panel inFIG. 10aconsistent with disclosed embodiments;

As shown inFIGS. 10a-10c, the display panel may comprise a first substrate10, a plurality of organic light-emitting units120, and at least one fingerprint recognition unit211. The plurality of organic light-emitting units120may be disposed on the first substrate10. The organic light-emitting unit120may have an inner side facing the viewers and an opposite outer side facing the first substrate10. The fingerprint recognition unit211may be disposed on the outer side of the organic light-emitting units120, i.e., the fingerprint recognition unit211may be disposed between the organic light-emitting units120and the first substrate10. The fingerprint recognition unit211may be configured to recognize or identify the fingerprint based on the light reflected by the touch object (such as finger) to the fingerprint recognition unit211.

The plurality of organic light-emitting units120may comprise a plurality of red organic light-emitting units121, a plurality of green organic light-emitting units122, and a plurality of blue organic light-emitting units123. Each organic light-emitting unit may have the inner side facing the light-exiting surface of the display panel and the outer side far away from the light-exiting surface of the display panel.

At the fingerprint recognition stage, at least one of the red organic light-emitting unit121and the green organic light-emitting unit122may be configured as the light source for the fingerprint recognition unit211to emit light. At least one of the red organic light-emitting unit121and the green organic light-emitting unit122, which is configured as the light source for the fingerprint recognition unit211, may have the area of a light-transparent region at the outer side of the organic light-emitting unit120smaller than the blue organic light-emitting unit123.

It should be noted that, the number and the layout of the organic light-emitting units in the display panel are for illustrative purposes, and are not intended to limit the scope of the present disclosure. In one embodiment, as shown inFIGS. 10a-10c, the first substrate1may be an array substrate.

Referring toFIG. 10bandFIG. 10c, each organic light-emitting unit120may have an inner side far away from the first substrate10and an opposite outer side facing the first substrate10. A first electrode313, a light-emitting function layer311, and a second electrode314may be sequentially disposed on the inner side of the organic light-emitting unit120. The organic light-emitting units120may include the red organic light-emitting units121, the green organic light-emitting units122, and the blue organic light-emitting units123.

Each organic light-emitting unit120may include a light-emitting function layer311. The light-emitting function layer311may have an inner side facing the light-exiting surface of the display panel and an opposite outer side far away from the light-exiting surface of the display panel. The light-emitting function layer311in the organic light-emitting unit120may a light-transparent region37and an opaque region36at the outer side of the light-emitting function layer311. For the top-emission type OLED display panel, the light-exiting surface of the display panel may be arranged at the outer side of the organic light-emitting unit120.

In particular, the light-emitting functional layer311may include a first auxiliary function layer, a light-emitting material or luminescent material layer, and a second auxiliary function layer. The first auxiliary functional layer may be a hole-type auxiliary functional layer, and may have a multilayer structure comprising, for example, one or more layers of a hole injection layer (HIL), a hole transport layer (HTL), and an electron blocking layer (EBL). The second auxiliary functional layer may be an electron-type auxiliary functional layer, and may have a multilayer structure comprising, for example, one or more layers of an electron transport layer (ETL), an electron injection layer (EIL), and a hole blocking layer (HBL).

When applied with an external electric field, electrons from the second electrode314and holes the first electrode313may be injected into the luminescent material layer in the luminescent functional layer311, and then recombined to generate excitons. The excitons migrate under the applied electric field, and the energy is transferred to the light-emitting molecules in the luminescent material. Then the electrons are stimulated to transit from the ground state to the excited state. The electrons at the excited state may release the energy through the radiation transition, thereby generating light.

In one embodiment, as shown inFIGS. 10b-10c, the first electrode313may be an anode and the second electrode314may be a cathode. In another embodiment, the first electrode313may be a cathode, the second electrode314may be an anode, which is not limited by the present disclosure.

In the disclosed embodiments shown inFIGS. 10a-10c, the display panel may comprise a plurality of organic light-emitting units120and at least one fingerprint recognition unit211disposed on the first substrate10. The plurality of organic light-emitting units120may comprise a plurality of red organic light-emitting units121, a plurality of green organic light-emitting units122, and a plurality of blue organic light-emitting units123. At the display stage, the red organic light-emitting unit121, the green organic light-emitting units122, and the plurality of blue organic light-emitting units123may emit light according to a predetermined sequence.

At the fingerprint recognition stage, because the light emitted by the blue organic light-emitting unit123has substantially short wavelength while the respective layers (e.g., organic insulating layers, inorganic insulating layers, polarizers, etc.) in the display panel strongly absorb light of short wavelength, the light emitted by the blue organic light-emitting unit123has lower light transmittance as compared to that of the red organic light-emitting unit121and green organic light-emitting unit122.

To address the above-mentioned concern, at least one of the red organic light-emitting unit121and the green organic light-emitting unit122may be configured to be the light source for the fingerprint recognition unit211and, meanwhile, the at least one of the red organic light-emitting unit121and the green organic light-emitting unit122, which is configured to be the light source for the fingerprint recognition unit211, may be configured to have the area of the light-transparent region at the outer side of the organic light-emitting unit120smaller than the blue organic light-emitting unit123.

Because the organic light-emitting unit configured as the light source for the fingerprint recognition unit211has a smaller area of the light-transparent region, stray light which is directly incident onto the fingerprint recognition unit211without being reflected by the touch object (e.g., finger) may be reduced. The stray light which is directly incident onto the fingerprint recognition unit211without being reflected by the touch object (e.g., finger) may not carry the fingerprint information, as a comparison, the light reflected by the touch body may carry the fingerprint information. Thus, through reducing the stray light, the noise in the fingerprint recognition may be suppressed, and the accuracy of the fingerprint recognition may be improved.

Further, as shown inFIG. 10c, the display panel may also include a second substrate20having an inner side facing the display module1and an opposite outer side. The first substrate10may have an inner side facing the organic light-emitting units120and an opposite outer side, and the second substrate20may be disposed on the outer side of the first substrate10. The fingerprint recognition units211may be disposed between the second substrate20and the first substrate10. The fingerprint recognition unit211and the second substrate20may be configured as a part of the fingerprint recognition module2, and the fingerprint recognition module2may also comprise a plurality of metal connection lines and IC drive circuits (not drawn inFIG. 10c).

In one embodiment, as shown inFIGS. 10b-10c, each organic light-emitting unit120may have the inner side facing the viewers and the outer side facing the first substrate10. The first electrode313, the light-emitting function layer311, and the second electrode314may be sequentially disposed on the inner side of the organic light-emitting unit120. The first electrode313may be a reflective electrode which may include, for example, an indium tin oxide (ITO) conductive layer, a reflective electrode layer (Ag), and an ITO conductive layer sequentially stacked. The ITO conductive layer comprises materials of a high work function, which may facilitate the hole injections. The light-emitting functional layer311of the red organic light-emitting unit121, the light-emitting functional layer311of the green organic light-emitting unit122, and the light-emitting functional layer311of the blue organic light-emitting unit123may be spaced apart from each other by a pixel-defining layer312.

Further, at the fingerprint recognition stage, both the red organic light-emitting unit121and the green organic light-emitting unit122may be configured as the light source for the fingerprint recognition. The area of the first electrode313in the red organic light-emitting unit121and the area of the first electrode313in the green organic light-emitting unit122each may be larger than the area of the first electrode313in the blue organic light-emitting unit123. On one hand, the light emitted from the light-emitting function layer311in the organic light-emitting unit120towards the first substrate10may be blocked by the first electrode313, which is disposed between the light-emitting function layer311and the fingerprint recognition unit211. On the other hand, as compared to the reflective electrode in the existing display panel, the reflective electrodes (i.e., the first electrodes313) in the red organic light-emitting unit121and green organic light-emitting unit122which are configured as the light source for the fingerprint recognition may be further extended outwards, for example, in the arrangement direction of the first electrodes313, thereby reducing the stray light incident onto the fingerprint recognition unit211and improving the accuracy of the fingerprint recognition.

That is, the area of the reflective electrode313in the blue organic light-emitting unit123may substantially remain the same, while the area of the reflective electrode313in the red organic light-emitting unit121and the area of the reflective electrode313in the green organic light-emitting unit122each may be expanded to block the stray light, as compared to the area of the reflective electrode in the existing display panel.

In addition, the reflective electrode313may be arranged adjacent to or in contact with the light-emitting functional layer311, such that the light emitted from the light-emitting functional layer311towards the first substrate10may be substantially close to the edge of the reflective electrode313. Thus, the reflective electrode313may be configured to extend a predetermined distance to prevent the light emitted from the light-emitting function layer from being directly incident onto the fingerprint recognition unit211. Further, when the reflective electrode313is extended to a certain extent, the reflective electrode313may completely prevent the stray light from being incident onto the fingerprint recognition unit211, thereby greatly improving the accuracy of the fingerprint recognition.

In one embodiment, as shown inFIGS. 10b-10c, in the organic light-emitting unit120which is configured as the light source for the fingerprint recognition unit211, a ratio between the area of the first electrode313and the area of the light-emitting function layer311may be approximately in the range of 1.2 to 6. In the organic light-emitting unit120which is not configured as the light source for the fingerprint recognition unit211, a ratio between the area of the first electrode313and the area of the light-emitting function layer311may be approximately in the range of 1 to 1.2.

For example, as shown inFIGS. 10b-10c, the opaque region36inFIG. 10bmay be the orthogonal projection of the first electrode313in the organic light-emitting unit120onto the first substrate10. When the red organic light-emitting unit121and the green organic light-emitting unit122are configured as the light source of the fingerprint recognition unit211, while the blue organic light-emitting unit123is not configured as the light source of the fingerprint recognition unit211, the ratio between the area of the opaque region36and the area of the light-emitting function layer311in the red organic light-emitting unit121and the ratio between the area of the opaque region36and the area of the light-emitting function layer311in the green organic light-emitting unit122each may be larger than the ratio between the area of the opaque region36and the area of the light-emitting function layer311in the blue organic light-emitting unit123.

Thus, in the organic light-emitting unit120which is configured as the light source for the fingerprint recognition unit211, through configuring the ratio between the area of the first electrode313and the area of the light-emitting function layer311to be approximately in the range of 1.2 to 6, the first electrode313may effectively prevent the light emitted from the light-emitting function layer from being directly incident onto the fingerprint recognition unit211. That is, the stray light may be effectively suppressed, the noise in the fingerprint recognition may be reduced, and the accuracy of the fingerprint recognition may be improved.

It is understood that, in the organic light-emitting unit120which is configured as the light source for the fingerprint recognition unit211, when the ratio of the area of the first electrode to the area of the light-emitting function layer is larger, the stray light may be more effectively blocked by the first electrode313, or more stray light may be blocked by the first electrode313. When the ratio between the area of the first electrode313and the area of the light-emitting function layer311is approximately 6, the first electrode may be able to block most of the stray light, greatly improving the accuracy of the fingerprint recognition.

FIG. 10dillustrates an exemplary first closed loop and an exemplary second closed loop consistent with disclosed embodiments. In one embodiment, as shown inFIGS. 10cto 10d, in the organic light-emitting unit120which is configured as the light source for the fingerprint recognition unit211, when being projected onto the first substrate10, the orthogonal projection of the border of the first electrode313in the organic light-emitting unit120may form a first closed loop101, and the orthogonal projection of the border of the light-emitting function layer311in the organic light-emitting unit120may form a second closed loop102.

Referring toFIG. 10d, the first closed loop101may surround the second closed loop102. For any point of the first closed loop101, the second closed loop102may have a corresponding point providing a short distance L between the point of the first closed loop101and the corresponding point of the second closed loop102. That is, the distance range between the first closed loop101and the second closed loop102may include a set of the shortest distances L corresponding to all the points on the first closed loop101.

The distance range between the first closed loop101and the second closed loop102may represent the range of the extending length of the first electrode in either direction in the plane of the first electrode. In one embodiment, the distance between the first closed loop101and the second closed loop102may be approximately in a range of 3 μm to 30 μm That is, the range of the extending length of the first electrode in either direction in the plane of the first electrode may be approximately in a range of 3 μm to 30 μm. In other words, the extending length of the first electrode in either direction in the plane of the first electrode may be approximately in a range of 3 μm to 30 μm. When the distance between the first closed loop101and the second closed loop102is approximately in a range of 3 μm to 30 μm, the first electrode may effectively reduce the stray light and improve the accuracy of fingerprint recognition.

FIG. 10eillustrates a partial enlarged schematic view of another exemplary S1region inFIG. 10aconsistent with disclosed embodiments.

As shown inFIGS. 10aand 10e, only the red organic light-emitting unit121may be configured as the light source of the fingerprint recognition unit211. The red organic light-emitting unit121may have the area of the light-transparent region at the outer side of the red organic light-emitting unit121smaller than the blue organic light-emitting unit123. Meanwhile, the red organic light-emitting unit121may have the area of the light-transparent region at the outer side of the red organic light-emitting unit121smaller than the green organic light-emitting unit122.

The light-emitting layer in the red organic light-emitting unit121may have an inner side facing the light-exiting surface of the display panel and an opposite outer side far away from the light-exiting surface of the display panel. Because only the red organic light-emitting unit is used as the light source for fingerprint recognition, it may be only necessary to block the light emitted from the outer side of the light-emitting layer in the red organic light-emitting unit121, for example, only the first electrode in the red organic light-emitting unit121may have to be extended. The first electrodes in the blue organic light-emitting unit123and green organic light-emitting unit122may not have to extended and, meanwhile, both the green organic light-emitting unit122and the blue organic light-emitting unit123may have a light-transparent region of the organic light-emitting unit larger than the red organic light-emitting unit121.

Thus, on one hand, the accuracy of the fingerprint recognition may be ensured, while the light-transparent regions of the organic light-emitting units may be sufficiently large to transmit the light reflected by the touch object (e.g., finger), thereby increasing the light intensity of the fingerprint signal light detected by the fingerprint recognition unit.

In addition, the light intensity of the fingerprint signal light detected by the fingerprint recognition unit may be increased by raising the operating voltage of the red organic light-emitting unit121.

In another embodiment, only the green organic light-emitting unit122may be configured as the light source of the fingerprint recognition unit211. The green organic light-emitting unit122may have the area of the light-transparent region at the outer side of the green organic light-emitting unit122smaller than the blue organic light-emitting unit123. Meanwhile, the green organic light-emitting unit122may have the area of the light-transparent region at the outer side of the green organic light-emitting unit122smaller than the red organic light-emitting unit121.

FIG. 11illustrates a schematic top view of another exemplary display panel consistent with disclosed embodiments.

As shown inFIG. 11, the area of the light-emitting function layer in the blue organic light-emitting unit123may be larger than the area of the light-emitting functional layer in the red organic light-emitting unit121. Meanwhile, the area of the light-emitting function layer in the blue organic light-emitting unit123may be larger than the area of the light-emitting function layer in the green organic light-emitting unit122.

Because the material of the light-emitting function layer of the blue organic light-emitting unit has a shorter life than the materials of the light-emitting functional layer in the red organic light-emitting mechanism and blue organic light-emitting unit, the area of the light-emitting function layer in the blue organic light-emitting unit may be desired to be larger, and the light-emitting function layer of the blue organic light-emitting unit may be able to be operated at a lower voltage.

For example, the operating voltage of the light-emitting functional layer in the red organic light-emitting unit121and the green organic light-emitting unit122may be set as approximately 3 V, and the operating voltage of the light-emitting functional layer in the blue organic light-emitting unit123may be set as approximately 2 V, thereby improving the lifetime of the blue organic light-emitting unit123. Accordingly, the lifetime of the red organic light-emitting unit, green organic light-emitting unit and blue organic light-emitting unit may be balanced, and the lifetime of the entire display panel may be improved.

FIG. 12aillustrates a schematic cross-sectional view of another exemplary display panel consistent with disclosed embodiments.FIG. 12billustrates a partial enlarged schematic view of an exemplary S1region inFIG. 12aconsistent with disclosed embodiments.

As shown inFIG. 12a, the display panel may comprise a first substrate10and a plurality of pixel driving circuits133arranged on the first substrate10. Each pixel driving circuit133may be electrically connected to a corresponding organic light-emitting unit120, and the fingerprint recognition unit211may be disposed between the first substrate10and the organic light-emitting unit120. For illustrative purposes,FIG. 12ashows three pixel driving circuits133, and each of the pixel driving circuits133may be electrically connected to the first electrode313in the corresponding organic light-emitting unit120. The fingerprint recognition units211, metal connecting lines, and an IC driving circuit (not drawn inFIG. 12a) may form a fingerprint recognition module, which may be embedded inside the display panel. Because the fingerprint recognition module is embedded inside the display panel, the thickness of the display panel may be reduced, and the thin-and-light design of the display panel may be realized.

In one embodiment, as shown inFIGS. 12aand 12b, when being projected onto the first substrate10, the pixel driving circuit133corresponding to the organic light-emitting unit120configured as the light source for the fingerprint recognition unit211, may have a larger orthogonal projection than, the pixel driving circuit133corresponding to the organic light-emitting unit120not configured as the light source for the fingerprint recognition unit211. The fingerprint recognition unit211may be arranged between the pixel driving circuit133and the first substrate10.

In one embodiment, as shown inFIGS. 12aand 12b, the pixel driving circuits133may comprise a plurality of scanning lines34and a plurality of data lines35. The scanning lines34and data lines35in the pixel driving circuits133, which are corresponding to the organic light-emitting unit120configured as the light source for the fingerprint recognition unit211, may be widened, thereby blocking the stray light. In another embodiment, the position or the size of the opaque elements in the pixel driving circuits133, which are corresponding to the organic light-emitting unit120configured as the light source for the fingerprint recognition unit211, may be modified, thereby blocking the stray light without affecting the original function of the opaque elements. For example, the position of the capacitive metal plate38may be changed, such that in addition to the capacitance storage function, the capacitive metal plate38may also be able to block the stray light.

FIG. 12cillustrates a circuit diagram of an exemplary pixel driving circuit consistent with disclosed embodiments.FIG. 12dillustrates an exemplary driving diagram of an exemplary pixel driving circuit consistent with disclosed embodiments.

Referring toFIGS. 12band 12c, the scanning lines34inFIG. 12bmay be a signal control line, a first scanning line, and a second scanning line in the pixel drive circuit inFIG. 12c. The data line35inFIG. 12bmay be a data line in the pixel drive circuit inFIG. 12c. The capacitive metal plate38inFIG. 12bmay be a storage capacitor C1in the pixel driving circuit inFIG. 12c. It is understood that the gate electrode, the source electrode and other non-transparent component of the first TFT T1and the second TFT T2in the pixel driving circuit may also be configured to block the stray light.

Referring toFIGS. 12cand 12d, the pixel driving circuit may include a data line, a first scanning line, a second scanning line, a signal control line, a light-emitting device, a storage capacitor C1, a driving transistor DTFT and five switching transistors T1to T5.

The first TFT T1may have a gate electrode electrically connected to the signal control line, a source electrode electrically connected to a first level terminal, and a drain electrode electrically connected to a first electrode of the storage capacitor C1.

The second switching transistor T2may have a gate electrode electrically connected to the first scanning line, a source electrode electrically connected to the ground, and a drain electrode electrically connected to a second electrode of the storage capacitor C1.

The third switching transistor T3may have a gate electrode electrically connected to the first scanning line, and a source electrode electrically connected to the second electrode of the storage capacitor C1.

The fourth switching transistor T4may have a gate electrode electrically connected to the first scanning line, a source electrode electrically connected to the data line, and a drain electrode electrically connected to the drain electrode of the third switching transistor T3.

The driving transistor DTFT may have a gate electrode electrically connected to the drain electrode of the fourth switching transistor T4, and a source electrode electrically connected to the data line, and a drain electrode electrically connected to the first electrode of the storage capacitor C1.

The fifth switching transistor T5may have a gate electrode electrically connected to the second scanning line, a source electrode electrically connected to the drain electrode of the driving transistor DTFT, and a drain electrode electrically connected to one terminal (e.g., an electrode) of the light-emitting device. The other terminal (e.g., another electrode) of the light-emitting device may be electrically connected to a second level terminal.

In particular, the first switching transistor T1, the third switching transistor T3, and the fifth switching transistor T5may be N-type switching transistors, while the driving transistor DTFT, the second switching transistor T2, and the fourth switching transistor T4may be P-type switching transistors.

Referring toFIG. 12d, the driving method of the pixel driving circuit may be explained as follows. Referring toFIG. 12dandFIG. 12c, the first scanning signal, the second scanning signal, the control signal, and the data signal are provided by the first scanning line, the second scanning line, the signal control line and the data line, respectively.

As shown inFIG. 12d, during the first time period, the first switching transistor T1, the second switching transistor T2, the fourth switching transistor T4, the fifth switching transistor T5may be turned on, while the third switching transistor T3may be turned off, the first level terminal may charge the storage capacitor C1.

During the second time period, the second switching transistor T2, the fourth switching transistor T4, and the fifth switching transistor T5may be turned on, while the first switching transistor T1and the third switching transistor T3may be turned off. The storage capacitor C1may be discharged until the voltage difference between the gate electrode and source electrode of the driving transistor DTFT is sustainably equal to the threshold voltage of the driving transistor DTFT.

During the third time period, the first switching transistor T1, the third switching transistor T3and the fifth switching transistor T5may be turned on, while the second switching transistor T2and the fourth switching transistor T4may be turned off. The first and second level terminals may provide a turn-on signal to the light-emitting device.

The fifth switching transistor T5may be turned off after the image displaying is completed, thereby protecting the light-emitting device.

FIG. 13illustrates a schematic cross-sectional view of another exemplary display panel consistent with disclosed embodiments.

As shown inFIG. 13, the display panel may further include a plurality of light-shielding pads50disposed between the organic light-emitting units120and the fingerprint recognition units211. Each organic light-emitting unit120may have an inner side facing the viewers and an opposite outer side facing the first substrate10. A first electrode313, a light-emitting function layer311, and a second electrode314may be sequentially disposed on the inner side of the organic light-emitting unit120.

In particular, the first electrode313may be reflective electrode. The organic light-emitting unit120configured as the light source for the fingerprint recognition unit211may correspond to at least one light-shielding pad50, and the organic light-emitting unit120not configured as the light source for the fingerprint recognition unit211may not correspond to any light-shielding pads50.

In one embodiment, as shown inFIG. 13, the organic light-emitting unit120configured as the light source for the fingerprint recognition unit211may be corresponding to two light-shielding pads50. For the organic light-emitting unit120configured as the light source for the fingerprint recognition unit211, the area of the combined orthogonal projection (CP) of the first electrode313and the two light-shielding pads50onto the first substrate10may be defined as Scp. For the organic light-emitting unit120not configured as the light source for the fingerprint recognition unit211, the area of the orthogonal projection of the first electrode313onto the first substrate10may be defined as Sp131. In particular, Scp is larger than Sp131.

For the organic light-emitting unit120configured as the light source for the fingerprint recognition unit211, the combined orthogonal projection (CP) of the first electrode313and the light-shielding pads50onto the first substrate10may be the union of the orthogonal projection (P313) of the first electrode313onto the first substrate10and the orthogonal projections (P50) of the first electrodes313onto the first substrate10. That is, when X and Y are sets, the union of X and Y includes all the elements in X and all the elements in Y, but without any other elements.

For illustrative purposes,FIG. 13only shows the combined orthogonal projection (CP) of the first electrode313in the red organic light-emitting unit121and the two light-shielding pads50onto the first substrate10. The combined orthogonal projection (CP) of the first electrode313in the green organic light-emitting unit122and the two light-shielding pads50onto the first substrate10can be similarly drawn.

Further, as shown inFIG. 13, for the organic light-emitting unit120configured as the light source for the fingerprint recognition unit211, the orthogonal projection of the edge (E313) of the first electrode313onto the first substrate10may fall within the orthogonal projections (P50) of the light-shielding pad50onto the first substrate10. Such an arrangement of the reflective electrode (i.e., the first electrode313) and the light-shielding pad50may be equivalent to extending the reflective electrode (i.e., the first electrode313) shown inFIG. 10c, i.e., equivalent to remaining the area of the reflective electrode in the blue organic light-emitting unit123unchanged while increasing at least one of the area of the reflective electrode in the red organic light-emitting unit121and the area of the reflective electrode in the green organic light-emitting unit122. Thus, for the organic light-emitting unit120configured as the light source for the fingerprint recognition unit211, the stray light may be prevented by the light-shielding pad50and the reflective electrode (i.e., the first electrode313) from being incident onto the fingerprint recognition unit211.

In one embodiment, as shown inFIG. 13, the display panel may include a first substrate10and a plurality of pixel driving circuits133disposed on the first substrate10. The pixel driving circuits133may comprise data lines, scanning lines, and capacitive metal plates (not drawn inFIG. 13). The light-shielding pad50may be arranged in the same layer as the data line, the scanning line or the capacitive metal plate, simplifying the fabrication process. That is, the light-shielding pad50may be fabricated without introducing an extra metal layer, thereby increasing the production efficiency and lowering the fabrication cost.

The light-shielding pad50may be made of a metal material or a non-metal material capable of shielding light. The light-shielding pad50may prevented the stray light from being incident onto the fingerprint recognition unit211, thereby improving the accuracy of fingerprint recognition.

It should be noted that, the disclosed embodiments and the features of the disclosed embodiments may be combined under conditions without conflicts, to achieve the purpose of improving the accuracy of fingerprint recognition.

For example, in one embodiment, the reflective electrode of the organic light-emitting unit configured as the light source may be extended outwards and, meanwhile, the pixel driving circuit may be designed to block a portion of the stray light (SeeFIG. 12b). In another embodiment, the reflective electrode of the organic light-emitting unit configured as the light source may be extended outwards and, meanwhile, the light-shielding pad may be disposed to block a portion of the stray light. In another embodiment, the light-shielding pad may be disposed to block a portion of the stray light and, meanwhile, the pixel driving circuit may be designed to block another portion of the stray light. In another embodiment, the reflective electrode of the organic light-emitting unit configured as the light source may be extended outwards to block a portion of the stray light, the pixel driving circuit may be designed to block another portion of the stray light, and the light-shielding pad may be disposed to block another portion of the stray light.

In addition, the present disclosure also provides a display panel in which the backlight is configured as a light source of the fingerprint recognition module.FIG. 14aillustrates a schematic three-dimensional view of an exemplary display panel consistent with disclosed embodiments.FIG. 14billustrates a schematic B1-B2sectional view of an exemplary display panel inFIG. 14aconsistent with disclosed embodiments.

As shown inFIGS. 14a-14b, the display panel may include a display module1, a fingerprint recognition module2, and at least one black matrix30. The display module1may include a first substrate10and a plurality of pixel circuits134. The first substrate10may include a display region A and a non-display region B surrounding the display region A, and the plurality of pixel circuits134may be disposed in the display region A of the first substrate10. The pixel circuit134may include a plurality of thin film transistors (TFTs) (not drawn inFIGS. 14a-14b), and each TFT includes a gate electrode, a source electrode and a drain electrode.

The first substrate10may have an inner side facing the TFTs included in the pixel circuits134and an opposite outer side, and the fingerprint recognition module2may be disposed on the outer side of the first substrate10and in the display region A. The black matrix30may be disposed between the TFTs (included in the pixel circuit134) and the fingerprint recognition module2, and the black matrix30may include a plurality of light-shielding regions31and a plurality of opening regions (or a light-transparent regions)32. The opening region32may be arranged between the light-shielding regions31. When being projected onto the first substrate10, the orthogonal projection of the gate, source, drain electrodes of the TFT (included in the pixel circuit134) may be disposed within the orthogonal projection of the light-shielding region31.

In the disclosed embodiments, the black matrix30may be disposed between the TFTs (included in the pixel circuit134) and the fingerprint recognition module2. The black matrix30may include a plurality of light-shielding regions31and a plurality of opening regions32arranged between the light-shielding regions31. When being projected onto the first substrate10, the orthogonal projection of the gate, source, drain electrodes of the TFT may be disposed within the orthogonal projection of the light-shielding region31.

The light-shielding regions31of the black matrix30may block the light emitted from the fingerprint recognition module2, such that the light may be less reflected by the gate, source, drain electrodes of the TFT, the possibility that the light reflected at the gate, source, drain electrodes of the TFT is incident onto the fingerprint recognition module2may be reduced, and the corresponding noise in the fingerprint recognition module2may be reduced accordingly.

In addition, through arranging a plurality of opening regions32in the black matrix30, the light emitted from the fingerprint recognition module2may be transmitted through the opening regions32and incident onto a finger pressing the display panel and, meanwhile, the light reflected by the fingerprint of the finger may be transmitted through the opening regions32. Thus, the signal-to-noise ratio of the fingerprint recognition module may be increased, and the fingerprint recognition accuracy of the fingerprint recognition module may be improved.

In one embodiment, the light-shielding regions31of the black matrix30may be made of black metal, a black organic material, or a material doped with a black pigment, which may significantly absorb light, facilitating the light absorption of the light emitted from the fingerprint recognition module2and incident onto the light-shielding region31of the black matrix30. Thus, the possibility that the light reflected at the gate, source, drain electrodes of the TFT is incident onto the fingerprint recognition module2may be further reduced, and the fingerprint recognition accuracy of the fingerprint recognition module may be improved. In one embodiment, the material of the black matrix30shading region31may include chromium (Cr).

It should be noted that, inFIG. 14b, the black matrix30may be disposed between the first substrate10and the fingerprint recognition module2, which is for illustrative purposes and is not intended to limit the scope of the present disclosure. In another embodiment, as shown inFIG. 15, the black matrix30may be disposed between the TFTs (included in the pixel circuit134) and the first substrate10. In another embodiment, as shown inFIG. 16, the display panel may include two black matrixes30. A first black matrix301may be disposed between the TFTs (included in the pixel circuit134) and the first substrate10, and a second black matrix302may be disposed between the first substrate10and the fingerprint recognition module2.

In one embodiment, the first substrate10may be a rigid substrate made from, for example, quartz or glass. In another embodiment, the first substrate10may be a flexible substrate made form, for example, polyimide. Certain exemplary display panels will be described in detail as follows, which is for illustrative purposes and is not intended to limit the scope of the present disclosure.

FIG. 17illustrates a schematic cross-sectional view of another exemplary display panel consistent with disclosed embodiments. As shown inFIG. 17, the display panel may comprise a first substrate10which is a rigid substrate, and a black matrix30disposed between the TFTs (included in the pixel circuit134) and the first substrate10. The display panel may further include a first planarization layer135and a second planarization layer136. The first substrate10may have an inner surface facing the black matrix30and an opposite outside surface. The first planarization layer135may be disposed on the inner surface of the first substrate10. The black matrix30may have an inner surface facing the TFTs (included in the pixel circuit134) and an opposite outside surface. The second planarization layer136may be disposed on the inner surface of the black matrix30. The second planarization layer136may cover the light-shielding regions31of the black matrix30and fill the opening regions32of the black matrix30.

The first substrate10may be made of quartz or glass, and the first substrate10may be configured to provide a support in the subsequent fabrication of the pixel circuit134, and the light-emitting units, etc.

In practice applications, due to the accuracy limitation of the surface polishing of the first substrate10and the degree of cleaning of the first substrate10, the first substrate10may have small defects formed on the surface. The first planarization layer135may be configured to fill the small defects on the first substrate10, thereby flattening the surface of the first substrate10.

Further, in the practical fabrication of the black matrix30, only the regions determined to be the light-shielding regions31of the black matrix30on the first substrate10may be deposited with a film, while the regions determined to be the opening regions32of the black matrix30on the first substrate10may not be deposited with any film. Thus, after the black matrix30is formed on the first substrate10, the light-shielding regions31and the opening regions32of the black matrix30may exhibit a thickness difference.

Then in the subsequent fabrication, a portion of the associated film forming the pixel circuit134may be trapped into the opening region32of the black matrix30and, thus the components in the pixel circuit134near the opening area32of the black matrix30may be displaced, causing a short circuit or open circuit in the pixel circuit134and degrading the display performance.

In the disclosed embodiments, through disposing the second planarization layer136on the inner surface of the black matrix30to cover the light-shielding regions31and fill the opening regions32of the black matrix30, the thickness difference between the light-shielding regions31and the opening regions32of the black matrix30may be eliminated. Accordingly, in the subsequent fabrication process, the component displacement in the pixel circuit134near the opening area32of the black matrix30may be suppressed, and the yield of the display panel may be improved. In another embodiment, the second planarization layer136may only fill the opening regions32of the black matrix30, i.e., the second planarization layer136may not cover the light-shielding regions31of the black matrix30.

The material of the first planarization layer135and the second planarization layer136may be any appropriate insulating material. In one embodiment, the first planarization layer135and the second planarization layer136may be made of polyimide, which has stable physical and chemical properties, good electrical insulation, simple production process, and low cost.

FIG. 18illustrates a schematic cross-sectional view of another exemplary display panel consistent with disclosed embodiments. As shown inFIG. 18, the display panel may comprise a first substrate10which is a rigid substrate, and a black matrix30disposed between the TFTs (included in the pixel circuit134) and the first substrate10. The display panel may further include a first planarization layer135. The black matrix30may have an inner surface facing the TFTs (included in the pixel circuit134) and an opposite outside surface. The first planarization layer135may be disposed on the inner surface of the black matrix30. The first planarization layer135may cover the light-shielding regions31of the black matrix30and fill the opening regions32of the black matrix30.

Similar as the display panel shown inFIG. 17, in the display panel inFIG. 18, through disposing the first planarization layer135on the inner surface of the black matrix30to cover the light-shielding regions31and fill the opening regions32of the black matrix30, the thickness difference between the light-shielding regions31and the opening regions32of the black matrix30may be eliminated. Accordingly, in the subsequent fabrication process, the component displacement in the pixel circuit134near the opening area32of the black matrix30may be suppressed, and the yield of the display panel may be improved.

The material of the first planarization layer135and the first substrate10may be any appropriate insulating material. In one embodiment, the first planarization layer135and the first substrate10may be made of polyimide, which has stable physical and chemical properties, good electrical insulation, simple production process, and low cost.

Further, in the disclosed display panels, the TFTs forming the pixel circuit134may have a top gate structure or a bottom gate structure, which may be determined according to various application scenarios. Certain exemplary display panels will be described in detail as follows, which is for illustrative purposes and is not intended to limit the scope of the present disclosure.

FIG. 19illustrates a schematic cross-sectional view of another exemplary display panel consistent with disclosed embodiments. The display panel may comprise a plurality of pixel circuits. For illustrative purposes,FIG. 19merely shows two pixel circuits, each of which includes only one TFT121a. As shown inFIG. 19, the TFT121amay have a bottom gate structure, and the TFT121amay comprise a gate electrode1211formed on the first substrate10, a first insulating layer1212formed on the gate electrode1211, an active layer1213formed on the first insulating layer1212, and a source electrode1214and a drain electrode1215formed on the active layer1213.

FIG. 20illustrates a schematic cross-sectional view of another exemplary display panel consistent with disclosed embodiments. The display panel may comprise a plurality of pixel circuits. For illustrative purposes,FIG. 20merely shows two pixel circuits, each of which includes only one TFT121a. As shown inFIG. 20, the TFT121amay have a top gate structure. The TFT121amay include an active layer1213formed on the first substrate10, a first insulating layer1212formed on the active layer1213, a gate electrode1211formed on the first insulating layer1212, a second insulating layer1216formed on the gate electrode1211, and a source electrode1214and a drain electrode1215formed on the second insulating layer1216.

Further, the display module often includes a plurality of light-emitting units. The pixel circuit of the display panel may have an outside surface facing the first substrate10and an opposite inner surface, and the plurality of light-emitting units may be disposed on the inner surface of the pixel circuit. The plurality of light-emitting units may be one-to-one corresponding to the plurality of pixel circuits. When the light emitted from the light-emitting unit is directly incident onto the fingerprint sensors in the fingerprint sensor module2, the noise in the fingerprint sensors in the fingerprint recognition module2may also be substantially large, degrading the fingerprint recognition accuracy of the fingerprint recognition module2.

In certain embodiments, as shown inFIG. 19orFIG. 20, when being projected onto the first substrate10, the orthogonal projection of the light-emitting unit15amay be disposed within the orthogonal projection of the light-shielding region31. Thus, the light emitted from the light-emitting unit15atowards the fingerprint recognition module2may be blocked by the light-shielding region31of the black matrix30. According, the signal-to-noise ratio of the fingerprint recognition module may be increased, and the fingerprint recognition accuracy of the display panel may be improved.

The display panel may include any appropriate type of display panels capable of displaying videos and/or images, such as plasma display panels, field emission display panels, organic light-emitting diode (OLED) display panels, light-emitting diode (LED) display panels, liquid crystal display (LCD) panels, quantum dots (QDs) display panels, electrophoretic display panels, etc.

In one embodiment, the display panel may be an OLED display panel. As shown inFIG. 19orFIG. 20, the light-emitting unit15amay include a first electrode151, a second electrode152, and a light-emitting layer153sandwiched between the first electrode151and the second electrode152. In certain embodiments, the first electrode151may be an anode, the second electrode152may be a cathode. In certain other embodiments, the first electrode151may be a cathode and the second electrode152may be an anode.

In another embodiment, the display panel may be an LCD panel, and the light-emitting unit12amay be a sub-pixel unit.

FIG. 21aillustrates a schematic top view of another exemplary display panel consistent with disclosed embodiments.FIG. 21billustrates a schematic C1-C2sectional view of another exemplary display panel inFIG. 21aconsistent with disclosed embodiments.

As shown inFIGS. 21aand 21b, the fingerprint recognition module2in the display panel may further comprise a second substrate20, and a plurality of isolated fingerprint recognition units211may be formed on the second substrate20. The second substrate20may have an inner surface facing the first substrate10and an opposite outside surface, and the plurality of isolated fingerprint recognition units211may disposed on the inner surface of the second substrate20. When being projected onto the first substrate10, the orthogonal projection of the fingerprint recognition unit211may be at least partially within the orthogonal projection of the opening region32of the black matrix30.

Through configuring the orthogonal projection of the fingerprint recognition unit211onto the first substrate10to be at least partially within the orthogonal projection of the opening region32of the black matrix30onto the first substrate10, the light reflected by the user fingerprint may be less shielded by the light-shielding region31of the black matrix30. Thus, more light may be transmitted through the opening region32of the black matrix30to be incident onto the fingerprint recognition unit211, and the signal-to-noise ratio of the fingerprint recognition unit211may be increased.

The display panel may further include a backlight source3, which may be disposed on the outside surface of the second substrate20. The backlight source3in the fingerprint recognition module2may be a collimated light source or a planar light source. Compared with surface light source, the collimated light source may reduce the crosstalk between different fingerprint recognition sensors caused by the light reflected by the user fingerprint and, accordingly, improve the accuracy of fingerprint recognition. However, the collimated light source is often thicker than the planar light source, which may increase the thickness of the display panel.

FIG. 22illustrates a fingerprint recognition principle of an exemplary fingerprint recognition module consistent with disclosed embodiments. The principle of the fingerprint recognition will be described in detail below with reference toFIGS. 9a, 9band22. Referring toFIGS. 9a, 9b, and22, at the fingerprint recognition stage, under the control of a driving chip (not drawn inFIGS. 9a, 9band22) electrically connected to the fingerprint sensor, the TFT T in the fingerprint recognition unit211may be turned on. When the user finger presses the display panel, the light emitted from the backlight source3in the fingerprint recognition module2may be divided into two parts: light a and light c. The light a may be transmitted through the opening area32of the black matrix30and incident onto the finger, forming reflected light b after being reflected by the surface of the fingerprint. The light c may be incident onto the light-shielding region31of the black matrix30and absorbed. The reflected light b may be incident onto the fingerprint recognition unit211, received by the photodiode D of the fingerprint recognition unit211, and converted into a current signal. The converted current signal may be transmitted to the signal detection line Data through the TFT T.

The fingerprint is often composed of a series of ridges41and valleys42disposed on the skin surface of the fingertip. Because the ridge41is in contact with the surface of the display panel while the valley42is not in contact with the surface of the display panel, the light reflectance at the valley42and the ridge41is different. Accordingly, the reflected light b formed at the valley42and the reflected light b formed at the ridge41may have different light intensity, and the current signals converted from the light intensity of the reflected light b formed at the valley42and the ridges41may have different magnitude, based on which fingerprint may be recognized.

To prevent the relative displacement of the display module1from the fingerprint recognition module2, and to maintain the good light transmittance of the display panel, in one embodiment, as shown inFIG. 22, the fingerprint recognition module2and the first substrate10are bonded by a LOCA40. The materials of the LOCA40may include an acrylic material and a silicon-based material.

Further, when the organic light-emitting layer is multiplexed as the light source of the fingerprint recognition module or an external light source is configured as the light source of the fingerprint recognition module, the present disclosure also provides certain exemplary display panels, in which the light reflected at different positions of the touch object selectively filtered by an angle-limiting film. Thus, the crosstalk caused by the light reflected from different positions of the touch objected to the same fingerprint recognition unit may be suppressed, and the accuracy of the fingerprint recognition may be improved.

An exemplary display panel may comprise a display module, a fingerprint recognition module, and an angle limiting film. The display module may include a first substrate and a plurality of organic light-emitting units disposed on the first substrate. The organic light-emitting unit may have an inner side facing the viewers and an opposite outer side facing the first substrate. The fingerprint recognition module may be disposed on the outer side of the organic light-emitting units. The fingerprint recognition module may comprise a second substrate, and at least one fingerprint recognition unit disposed on the second substrate. The fingerprint recognition unit may be configured to recognize or identify the fingerprint based on the light reflected by the touch object (such as the user finger) to the fingerprint recognition unit.

The angle-limiting film may be disposed between the display module and the fingerprint recognition module. The angle-limiting film may filter out the light, whose incident angle on the angle-limiting film is larger than the transmitting angle of the angle-limiting film, from the light reflected by the touch object (such as the user finger) to the fingerprint recognition unit. In particular, the light transmittance of the light normally (or perpendicularly) incident onto the angle-limiting film is defined as A, and the transmitting angle of the angle-limiting film is defined as the incident angle of the light with kA light transmittance with respect to the angle-limiting film, where 0<k<1.

In practical applications, the light reflected at different positions of the touch object may be incident onto the same fingerprint recognition unit. For example, the light reflected by the ridge and adjacent valley of the touch object may be incident onto the same fingerprint recognition unit. Thus, the fingerprint recognition unit may be unable to detect the exact locations of the ridge and valley of the fingerprint, which may result serious crosstalk in the fingerprint recognition, and degrade the fingerprint recognition accuracy and sensitivity of the fingerprint recognition sensor.

To address the one or more problems set forth above, in the disclosed embodiments, the angle-limiting film may be disposed between the display module and the fingerprint recognition module, and the angle-limiting film may be configured to filter out the light, whose incident angle on the angle-limiting film is larger than the transmitting angle of the angle-limiting film, from the light reflected by the touch object to the fingerprint recognition unit. Thus, the crosstalk, which is caused by the light reflected at different positions of the touch object (such as the ridge and adjacent valley of the touch object) to the same fingerprint recognition unit, may be suppressed.

That is, because the angle-limiting film is able to selectively filter out the light reflected at different positions of the touch object to the same fingerprint recognition unit, the light with an incident angle larger than the transmitting angle of the angle-limiting film may be filtered by the angle-limiting film. Thus, the crosstalk, which is caused by the light reflected at different positions of the touch object to the same fingerprint recognition unit, may be suppressed, and the fingerprint recognition accuracy and sensitivity may be improved.

Certain exemplary display panels comprising the angle-limiting film will be explained in detail as follows.

FIG. 23aillustrates a schematic top view of another exemplary display panel consistent with disclosed embodiments.FIG. 23billustrates a schematic D1-D2sectional view of another exemplary display panel inFIG. 23aconsistent with disclosed embodiments.

As shown inFIGS. 23a-23b, the display panel may include a display module1, a fingerprint recognition module2, and an angle-limiting film4. The display module1may include a first substrate10and a plurality of organic light-emitting units120disposed on the first substrate10. The first substrate10may have an inner side facing the organic light-emitting units120and an opposite outer side, and the fingerprint recognition module2may be disposed on the outer side of the first substrate10and in the display region A. The fingerprint recognition module2may include a second substrate20and at least one fingerprint recognition unit211disposed on the second substrate20. The angle-limiting film4may be disposed between the display module1and the fingerprint recognition module2.

The fingerprint recognition module2may recognize the fingerprint based on the light reflected by the touch object to the fingerprint recognition unit211. The angle-limiting film4may be able to filter out the light, whose incident angle on the angle-limiting film4is larger than the transmitting angle of the angle-limiting film4, from the light reflected by the touch object to the fingerprint recognition unit211.

In particular, the light transmittance of the light normally (or perpendicularly) incident onto the angle-limiting film4is defined as A, and the transmitting angle of the angle-limiting film4is defined as the incident angle of the light with kA light transmittance with respect to the angle-limiting film4, where 0<k<1. The light, whose incident angle on the angle-limiting film4is larger than the transmitting angle of the angle-limiting film4, may be completely filtered out from the light reflected by the touch object to the fingerprint recognition unit211, by the angle-limiting film4.

In one embodiment, k may be configured to be 0.1, i.e., the transmitting angle of the angle-limiting film4is defined as the incident angle (with respect to the angle-limiting film4) of the light with 0.1 A light transmittance.

Referring toFIG. 23b, the light emitted from the light source towards the touch object may correspond to different light sources, for example, the light denoted by the solid arrows inFIG. 23bis emitted from the organic light-emitting unit120, while the light denoted by the dashed arrows inFIG. 23bis emitted from the backlight source3. The fingerprint recognition unit211may be able to recognize the fingerprint based on the light emitted from any light sources.

The touch object is often a user finger, where the fingerprint is composed of a series of ridges41and valleys42disposed on the skin surface of the fingertip. Because the ridges41and valleys42have different distance to the fingerprint recognition unit211, the light, which is respectively reflected by the ridges41and the valley42and then received by the fingerprint recognition unit42, may be different in light intensity. Thus, the current signals converted from the light intensity of the light respectively reflected by the ridges41and the valley42may be different in magnitude, based on which fingerprint may be recognized.

It should be noted that, the touch object may also be a palm, and the fingerprint recognition unit may realize detection and recognition functions based on the palmprint.

In one embodiment, the organic light-emitting unit120may be configured as the light source for the fingerprint recognition module2, and the fingerprint recognition module2may recognize the fingerprint based on the light, which is emitted from the organic light-emitting unit120and then reflected by the touch object to the fingerprint recognition unit211(such as the solid arrows shown inFIG. 23b). The angle-limiting film4may be able to filter out the light, whose incident angle on the angle-limiting film4is larger than the transmitting angle of the angle-limiting film4, from the light emitted from the organic light-emitting unit120and then reflected by the touch object to the fingerprint recognition unit211.

Thus, the crosstalk, which is caused by the light emitted from the organic light-emitting unit120and then reflected at different positions of the touch object to the same fingerprint recognition unit211, may be suppressed. Accordingly, the fingerprint recognition accuracy and sensitivity of the fingerprint recognition module2may be improved.

In one embodiment, when the light source for the fingerprint recognition is the organic light-emitting unit120, for the light reflected perpendicular to the touch body, the light transmitted through the display module1and then incident onto the fingerprint recognition unit211may be configured to have the light transmittance greater than approximately 1%. When the fingerprint recognition unit211recognizes the fingerprint based on the light emitted from the organic light-emitting unit120, while the light transmittance of the light reflected perpendicular to the touch body then transmitted through the display module1and incident onto the fingerprint recognition unit211is substantially low, the light intensity received by the fingerprint recognition unit211may be substantially low, degrading the accuracy of the fingerprint recognition.

To solve one or more problems set forth above, the thickness of the various films in which the light is transmitted through may be adjusted, such that the light transmittance of the light, which is reflected perpendicular by the touch body and then transmitted through the display module1to be incident onto the fingerprint recognition unit211may be adjusted, accordingly.

In one embodiment, the display panel may include a light-exiting surface and a non-light-exiting surface. The organic light-emitting unit120may have an outer side facing the first substrate10and an opposite inner side far away from the first substrate10. The first substrate10have an outer side far away from the organic light-emitting unit120and an opposite inner side. The light-exiting surface of the display panel may be arranged at the inner side of the organic light-emitting unit120, where the inner side of the organic light-emitting unit120is arranged far away from the first substrate10. The non-light-exiting surface of the display panel may be arranged at the outer side of the substrate10, where the outer side of the substrate10is arranged far away from the organic light-emitting unit120.

When the fingerprint recognition unit211recognizes the fingerprint based on the light emitted from the organic light-emitting unit120, the ratio of the brightness at the light-exiting surface to the brightness at the non-light-exiting surface may be greater than approximately 10:1. The light at the non-light-exiting surface of the display panel may affect the fingerprint recognition, which is performed by the fingerprint recognition unit211based on the light emitted from the organic light-emitting unit120. For example, a crosstalk may be introduced to the light detected by the fingerprint recognition unit211. When the brightness of the display panel at the non-light-exiting surface is too large, the accuracy of the fingerprint recognition may be significantly reduced.

It should be noted that,FIGS. 23aand 23bshow the relative positions of the organic light-emitting unit120and the fingerprint recognition unit211, which is for illustrative purposes and is not intended to limit the scope of the present disclosure. The relative positions of the organic light-emitting unit120and the fingerprint recognition unit211may be determined according to various application scenarios, as long as the light emitted from the organic light-emitting unit120can be reflected to the fingerprint recognition unit211by the touch object.

In one embodiment, the display panel may further include a backlight source3. The second substrate20may have an inner side facing the organic light-emitting unit120and an opposite outer side, and the backlight source3may be disposed on the outer side of the second substrate20. The fingerprint recognition unit211may recognize the fingerprint based on the light, which is emitted from the backlight source3and then reflected by the touch object to the fingerprint recognition unit211(such as the dashed arrows shown inFIG. 23b).

The angle-limiting film4may be able to filter out the light, whose incident angle on the angle-limiting film4is larger than the transmitting angle of the angle-limiting film4, from the light emitted from the backlight source3and then reflected by the touch object to the fingerprint recognition unit211. Thus, the crosstalk, which is caused by the light emitted from the backlight source3and then reflected at different positions of the touch object to the same fingerprint recognition unit211, may be suppressed. Accordingly, the accuracy and sensitivity of the fingerprint recognition may be improved.

In one embodiment, the light emitted from the backlight source3may be incident onto the touch object after being transmitted through the gap between two adjacent fingerprint recognition units211. In one embodiment, when the light source for the fingerprint recognition is the backlight source3, for the light reflected perpendicular to the touch body, the light transmitted through the display module1and then incident onto the fingerprint recognition unit211may be configured to have the light transmittance greater than approximately 10%. When the light transmittance of the light, which is reflected perpendicular to the touch body and incident onto the fingerprint recognition unit211after being transmitted through the display module1, is substantially low, the light intensity received by the fingerprint recognition unit211may be substantially low, degrading the accuracy of the fingerprint recognition.

Compared to the fingerprint recognition performed by the fingerprint recognition unit211based on the light emitted from the organic light-emitting unit120, during the fingerprint recognition performed by the fingerprint recognition unit211based on the light emitted from the backlight source3, the light emitted from the backlight source3may be transmitted through a larger number of films to be incident onto the fingerprint recognition unit211. A larger number of films may indicate a larger total thickens of the films. Thus, during the fingerprint recognition performed by the fingerprint recognition unit211based on the light emitted from the backlight source3, for the light reflected perpendicular to the touch body, the light transmitted through the display module1and then incident onto the fingerprint recognition unit211may be desired to have higher light transmittance.

It should be noted that, the position and type of the backlight source3is not limited by the present disclosure, the backlight source3may be a point light source or a planar light source, as long as the light emitted from the backlight3can be reflected to the fingerprint recognition unit211by the touch object. Meanwhile, the light indicated by the solid arrow and the dashed arrow inFIG. 23bmerely illustrate a certain light beam emitted from the organic light-emitting unit120and the backlight3, however, the light emitted from the organic light-emitting unit120and the light source for fingerprint recognition may be divergent.

In addition, the light source for fingerprint recognition is not limited by the present disclosure, as long as the light emitted from the light source for fingerprint recognition can be reflected to the fingerprint recognition unit211by the touch object. For example, the light source for fingerprint recognition may be the organic light-emitting unit120, or may be the backlight3which is an external light source rather than being disposed inside the display module.

FIG. 24aillustrates a schematic top view of an exemplary angle-limiting film consistent with disclosed embodiments.FIG. 24billustrates a schematic E1-E2sectional view of an exemplary angle-limiting film inFIG. 24aconsistent with disclosed embodiments.

As shown inFIGS. 24a-24b, the angle-limiting film4may include a plurality of opaque regions41aand light-transparent regions41barranged in a plane parallel to the plane of the second substrate20. The plurality of opaque regions41aand light-transparent regions41bmay be alternately arranged along a same direction.

Light absorption materials may be disposed in the opaque regions41aof the angle-limiting film4. Thus, light incident onto the opaque regions41amay be absorbed by the light absorption material disposed in the opaque regions41a. That is, the light reflected by the touch body and then incident onto the opaque regions41aof the angle-limiting film4may not be received by the fingerprint recognition unit211. In other words, the light reflected by the touch body to the opaque regions41aof the angle-limiting film4may be effectively filter out by the angle-limiting film4.

As shown inFIG. 24b, because the light incident onto the opaque regions41ais absorbed by the light absorption material, the transmitting angle of the angle-limiting film4may be configured to satisfy the following equation:

θ=arctan⁢ph,(1)
where θ is transmitting angle of the angle-limiting film4, p is the width of the light-transparent region41bin the direction where the light transmission regions41bare arranged, and h is the thickness of the angle-limiting film4. As shown inFIG. 24b, θ, p, and h have a relationship indicated by Eq (1) and, thus, the transmitting angle of the angle-limiting film4may satisfy the Eq (1).

Because the light incident onto the opaque region41ais absorbed by the light absorption material in the opaque region41a, the light having an incident angle (onto the angle-limiting film4) larger than the calculated transmitting angle of the angle-limiting film4may be filtered by the angle-limiting film4. The light having an incident angle (onto the angle-limiting film4) larger than the calculated transmitting angle of the angle-limiting film4may not be desired for fingerprint recognition.

Through configuring the angle-limiting film4in the display panel, the light having an incident angle (onto the angle-limiting film4) larger than the calculated transmitting angle of the angle-limiting film4may be prevented from being incident onto the fingerprint recognition unit211, thereby suppressing the interference in the fingerprint recognition.

In one embodiment, when the angle-limiting film4includes a plurality of opaque regions41aand light-transparent regions41barranged in a plane parallel to the plane of the second substrate20, in which the plurality of opaque regions41aand light-transparent regions41bare alternately arranged along a same direction and the light absorption materials are disposed in the opaque regions41a, the diffusing distance of the angle-limiting film4may be configured to satisfy the following equation:

Δ⁢⁢X=p·(H+h)h,(2)
where ΔX is the diffusing distance of the angle-limiting film4, H is the thickness of the display module1.

The diffusing distance of the angle-limiting film4refers to the distance between two reflection points on the touch object, at which the actually detected light (e.g., fingerprint signal light) and the disturbed light (e.g., fingerprint noise light) corresponding to the same fingerprint recognition unit211are reflectively reflected. That is, one reflection point corresponds to the actually detected light (e.g., fingerprint signal light), and the other reflection point corresponds to the disturbed light (e.g., fingerprint noise light), in which the actually detected light (e.g., fingerprint signal light) and the disturbed light (e.g., fingerprint noise light) is going to be received by the same fingerprint recognition unit211.

The actually detected light is defined as the reflected light (i.e., the light reflected by the touch object) which has the smallest incident angle onto the fingerprint recognition unit211. The disturbed light is defined as the reflected light (i.e., the light reflected by the touch object) which has a larger incident angle onto the fingerprint recognition unit211than the actually detected light.

FIG. 24cillustrates a schematic cross-sectional view of another exemplary display panel consistent with disclosed embodiments.

As shown inFIG. 24c, the fingerprint recognition unit211may recognize the fingerprint based on the light, which is emitted from the organic light-emitting unit120, then reflected by the touch object to the fingerprint recognition unit211. The light denoted by the solid arrow inFIG. 24cmay be the reflected light (i.e., the light reflected by the touch object) which has the smallest incident angle onto the fingerprint recognition unit211, i.e., the actually detected light. The light denoted by the dashed arrow inFIG. 24cmay be the reflected light (i.e., the light reflected by the touch object) which has a larger incident angle onto the fingerprint recognition unit211than the actually detected light, i.e., the disturbed light.

Without the angle-limiting film4, the actually detected light and the disturbed light, which is the reflected light formed at different positions of the touch object, such as two adjacent ridges41, may be incident onto the same fingerprint recognition unit211. That is, interference may be generated in the fingerprint recognition process.

FIG. 24dillustrates a diffusing distance of an exemplary angle-limiting film inFIG. 24aconsistent with disclosed embodiments. Referring toFIG. 24candFIG. 24d, the diffusing distance ΔX of the angle-limiting film4refers to the distance between two reflection points on the touch object, at which the actually detected light (e.g., fingerprint signal light) and the disturbed light (e.g., fingerprint noise light) corresponding to the same fingerprint recognition unit211are reflectively reflected.

The incident angle of the actual detected light onto the fingerprint recognition unit211may be approximately 0°. For the disturbed light which could be transmitted through the angle-limiting film4, the incident angle onto the fingerprint recognition may have a minimum value as the transmitting angle of the angle-limiting film4. Thus,

tan⁢⁢θ=ph=Δ⁢⁢XH+h,
and the diffusing distance of the angle-limiting film4may also satisfy this question. A larger diffusing distance of the angle-limiting film4may indicate a lower accuracy and sensitivity of the fingerprint recognition in the display panel.

The angle-limiting film4inFIG. 24amay be arranged in a one-dimensional (1D) structure, in which the light-transparent regions41band the opaque regions41aare alternately arranged in the horizontal direction. In another embodiment, the angle-limiting film4may be arranged in a two-dimensional (2D) structure.FIG. 24eillustrates a schematic top view of another exemplary angle-limiting film consistent with disclosed embodiments. As shown inFIG. 24e, the light-transparent regions41band the opaque regions41amay be alternately arranged in both the horizontal direction and the vertical direction.

As compared to the angle-limiting film4having the 1D structure inFIG. 24a, the angle-limiting film4having the 2D structure inFIG. 24emay be able to selectively filter the light incident onto the angle-limiting film4from every direction.

FIG. 25aillustrates a schematic top view of another exemplary angle-limiting film consistent with disclosed embodiments.FIG. 25billustrates a schematic F1-F2sectional view of another exemplary angle-limiting film inFIG. 25aconsistent with disclosed embodiments.

As shown inFIGS. 25a-25b, the angle-limiting film4may have a porous structure including a plurality of through-holes41c, and the side wall411of the through-holes41cmay absorb the light incident on the side wall411. That is, the light absorbed by the side wall411of the through-holes41cmay be no longer incident onto the fingerprint recognition unit211.

In one embodiment, the porous structure41cmay be a glass capillary structure in which a light absorption material in black may be coated on the side wall411of the glass capillary, such that that the side wall411may absorb the light incident onto the side wall411. That is, the light may be partially filtered by the angle-limiting film4.

In one embodiment, the light absorption material may be provided between the adjacent through-holes41cin the porous structure. In another embodiment, the light absorption material may not be provided between the adjacent through-holes41cin the porous structure.

In particular, because the side wall411of the through-holes41cis capable of absorbing light incident onto the side wall411, the transmitting angle of the angle-limiting film4may satisfy the following formula:

θ=arctan⁢dh,(3)
where θ is transmitting angle of the angle-limiting film4, d is the diameter of the through-hole41c, andhis the thickness of the angle-limiting film4. As shown inFIG. 25b, θ, d, and h have a relationship indicated by Eq (3) and, thus, the transmitting angle of the angle-limiting film4may satisfy the Eq (3).

Meanwhile, because the side wall411of the through-holes41cis able to absorb light incident onto the side wall411, the diffusing distance of the angle-limiting film4may be configured to satisfy the following equation:

Δ⁢⁢X=d·(H+h)h,(4)
where ΔX is the diffusing distance of the angle-limiting film4, and H is the thickness of the display module1.

Eq (4) may be derived similarly to Eq (2), i.e. the diffusing distance of the angle-limiting film4shown inFIG. 24a, which is not repeated here. Similarly, a larger diffusing distance of the angle-limiting film4may indicate a lower accuracy and sensitivity of the fingerprint recognition in the display panel.

It should be noted that, from a top view of the angle-limiting film4, the aperture of the through-hole41cincluded in the porous structure may have a circular shape as shown inFIG. 25a, or have a hexagonal shape as shown inFIG. 25c, which is not limited by the present disclosure. In practical applications, the aperture of the through-hole41cincluded in the porous structure may have any appropriate shapes according to various application scenarios.

FIG. 26aillustrates a schematic top view of another exemplary angle-limiting film consistent with disclosed embodiments. As shown inFIG. 26a, the angle-limiting film4may include a plurality of optical fibers43arranged in parallel and extending in a same direction.FIG. 26billustrates a schematic cross-sectional view along an extending direction of optical fibers in an exemplary angle-limiting film inFIG. 26aconsistent with disclosed embodiments.

As shown inFIGS. 26a-26b, each optical fiber43may include a core431and a clad432, and a light absorption material433may be provided between any two adjacent optical fibers43. When the light emitted from the optical fiber43is incident onto regions between two adjacent optical fibers43, the light absorption material433may absorb the incident light. That is, the light may be partially filtered by the angle-limiting film4.

In particular, the refractive index of the core431and the clad432of the optical fiber43is different, the transmitting angle of the angle-limiting film4may satisfy the following formula:
n·sin θ=√{square root over (ncore2−nclad2)},  (5)
where θ is transmitting angle of the angle-limiting film4, n is the refractive index of the film layer in the display module1that is in contact with the angle-limiting film4, ncoreis the refractive index of the core431of the optical fiber43, and ncladis the refractive index of the clad432of the optical fiber43.

As shown inFIG. 26b, for the light reflected by the touch object, when the incident angle onto the angle-limiting film4is larger than the transmitting angle θ of the angle-limiting film4, the light may not undergo the total internal reflection (TIR) in the optical fiber43, i.e., the light may be transmitted through the optical fiber43, and then absorbed by the light absorption material433disposed between any two adjacent optical fibers43in the angle-limiting film4. That is, the light transmitted through the optical fiber43may be filtered by the angle-limiting film4, and may be no longer incident onto the fingerprint recognition unit211.

In other words, the angle-limiting film4may effectively filter out the light, whose incident angle on the angle-limiting film is larger than the transmitting angle θ of the angle-limiting film4, from the light reflected by the touch object (such as the user finger) to the fingerprint recognition unit211. Thus, the crosstalk, which is caused by the light emitted from the backlight source3and then reflected at different positions of the touch object to the same fingerprint recognition unit211, may be suppressed. Accordingly, the accuracy and sensitivity of the fingerprint recognition may be improved.

When the angle-limiting film4includes a plurality of optical fibers43arranged in parallel and extending in a same direction, the refractive index of the core431and the clad432of the optical fiber43is different, and the light absorption material433is provided between any two adjacent optical fibers43, the diffusing distance of the angle-limiting film4may be configured to satisfy the following equation:
ΔX=H·tan θ,  (6)
where ΔX is the diffusing distance of the angle-limiting film4, and H is the thickness of the display module1.

As shown inFIG. 26c, the incident angle of the actual detected light onto the fingerprint recognition unit211may be approximately 0°. For the disturbed light which could be transmitted through the angle-limiting film4, the incident angle onto the fingerprint recognition may have a minimum value as the transmitting angle of the angle-limiting film4, i.e., the critical angle of the total internal reflection of in the optical fiber43. Thus,

tan⁢⁢θ=Δ⁢⁢XH.
A larger diffusing distance of the angle-limiting film4may indicate a lower accuracy and sensitivity of the fingerprint recognition in the display panel.

FIG. 27aillustrates a schematic top view of another exemplary angle-limiting film consistent with disclosed embodiments.FIG. 27billustrates a schematic G1-G2sectional view of another exemplary angle-limiting film inFIG. 27aconsistent with disclosed embodiments.

As shown inFIGS. 27a-27b, the angle-limiting film4may include a plurality of pillars43arranged in parallel and extending in a same direction. Each pillar43may include a core451and a clad452with the same refractive index. The material forming the clad452may include a light absorption material, such that the light transmitted through the core451and then incident onto the clad452may be absorbed by the clad452. That is, the light transmitted through the core451and then incident onto the clad452may be no longer incident onto the fingerprint recognition unit211. Further, a light absorption material433may be provided or not provided between any two adjacent pillars45.

In particular, the light transmitted through the core451and then incident onto the clad452may be absorbed by the clad452, the transmitting angle of the angle-limiting film4may satisfy the following formula:

θ=arctan⁢Dh,(7)
where θ is transmitting angle of the angle-limiting film4, D is the diameter of the core451, and h is the thickness of the angle-limiting film4. As shown inFIG. 27b, θ, D, and h have a relationship indicated by Eq (7) and, thus, the transmitting angle of the angle-limiting film4may satisfy the Eq (7).

When the angle-limiting film4includes the plurality of pillars43arranged in parallel and extending in a same direction, each pillar43includes a core451and a clad452with the same refractive index, and the material forming the clad452includes a light absorption material, the diffusing distance of the angle-limiting film4may be configured to satisfy the following equation:

Δ⁢⁢X=D·(H+h)h,(8)
where ΔX is the diffusing distance of the angle-limiting film4, H is the thickness of the display module1.

Eq (8) may be derived similarly to Eq (2), i.e. the diffusing distance of the angle-limiting film4shown inFIG. 24a, which is not repeated here. Similarly, a larger diffusing distance of the angle-limiting film4may indicate a lower accuracy and sensitivity of the fingerprint recognition in the display panel.

It should be noted that, from a top view of the angle-limiting film4, the aperture of the pillar45included in the angle-limiting film4may have a circular shape as shown inFIG. 27a. In practical applications, the aperture of the pillar45may have any appropriate shapes according to various application scenarios, which is not limited by the present disclosure.

In one embodiment, the angle-limiting film4may have a diffusing distance of approximately less than 400 μm. When the diffusing distance of the angle-limiting film4increases, the distance between two reflection points on the touch object, at which the actually detected light and the disturbed light corresponding to the same fingerprint recognition unit211are respectively reflected, may increase accordingly. When the distance between two reflection points on the touch object, at which the actually detected light and the disturbed light corresponding to the same fingerprint recognition unit211are respectively reflected, is larger than the distance between the valley42and the adjacent ridge41in the fingerprint, errors may be generated in the fingerprint recognition process. Thus, the fingerprint may not be successfully recognized, and the accuracy of the fingerprint recognition may be significantly degraded.

In one embodiment, the organic light-emitting unit120may be configured as the light source for the fingerprint recognition module2, and the fingerprint recognition unit211may recognize the fingerprint based on the light, which is emitted from the organic light-emitting unit120and then reflected to the fingerprint recognition unit211by the touch object. At the fingerprint recognition stage, within a range of twice the diffusing distance of the angle-limiting film4, only one organic light-emitting unit120may be configured to be emit light.

Thus, the probability that the light emitted from different organic light-emitting units120is reflected to the same fingerprint recognition unit211by different positions of the touch object may be significantly reduced. The crosstalk, which is caused by the light emitted from the organic light-emitting units120and then reflected by different positions of the touch object to the same fingerprint recognition unit211, may be suppressed. Accordingly, the accuracy and sensitivity of the fingerprint recognition may be improved.

In one embodiment, an optical adhesive layer (e.g., formed of LOCA) may be provided between the fingerprint recognition module2and the angle-limiting film4, for bonding the fingerprint recognition module2to the angle-limiting film44. The fingerprint recognition unit211may include an optical fingerprint sensor capable of detecting and recognizing the fingerprint based on the light reflected by the touch object. The material forming the fingerprint recognition unit211may include, for example, amorphous silicon or gallium arsenide or arsenide sulfide, or other light absorption materials, which is not limited by the present disclosure.

In one embodiment, as shown inFIGS. 23band 24c, the display panel may also include a thin film encapsulation layer16, a first polarizer11and a cover glass14sequentially disposed on the organic light-emitting units120. The second substrate20, which is the substrate of the fingerprint recognition unit211, may be a glass substrate or a flexible substrate. The cover glass14may be attached to the first polarizer11by liquid optical clear adhesive (LOCA).

In one embodiment, the display panel may also include a touch control electrode layer which may be disposed between the thin film encapsulation layer16and the first polarizer11. In another embodiment, the display panel may also include a touch control electrode layer which may be disposed between the cover glass14and the first polarizer11. The display panel integrated with the touch control electrodes may have the touch control function in addition to the display function.

It should be noted that, the accompanying drawings illustratively show the size of various elements and the thickness of various layers, but do not represent the actual dimensions of the various elements and various layers in the display panel.

In the disclosed embodiments, the angle-limiting film4may be disposed between the display module1and the fingerprint recognition module2. The angle-limiting film4may be able to filter out the light, whose incident angle on the angle-limiting film4is larger than the transmitting angle of the angle-limiting film4, from the light reflected by the touch object to the fingerprint recognition unit211. That is, the angle-limiting film4may be able to selectively filter the light reflected at different positions of the touch object to the same fingerprint recognition unit211. Thus, the crosstalk, which is caused by the light reflected at different positions of the touch object to the same fingerprint recognition unit211, may be suppressed, and the fingerprint recognition accuracy and sensitivity may be improved.

Further, in an existing display device with a fingerprint recognition function, the light emitted from the light sources for the fingerprint recognition is reflected by the finger to a plurality of fingerprint recognition units. Thus, in addition to receiving a fingerprint signal from the corresponding position, each fingerprint recognition unit also receives fingerprint signals from other positions, degrading the accuracy of the fingerprint recognition.

To solve one or more problems set forth above, the present disclosure provides an improved display panel.

FIG. 28aillustrates a schematic cross-sectional view of another exemplary display panel consistent with disclosed embodiments.FIG. 28billustrates a partial top view of another exemplary display panel inFIG. 28aconsistent with disclosed embodiments.FIG. 28cillustrates a scanning diagram at a fingerprint recognition stage of another exemplary display panel inFIG. 28aconsistent with disclosed embodiments.

The organic light-emitting layer12may include a plurality of organic light-emitting units120. The fingerprint recognition module2may include a fingerprint recognition layer21. The cover glass14may have a first surface far away from the first substrate10and an opposite second surface facing the first substrate10. The light-exiting surface of the display panel may be defined as the first surface of the cover glass14.

At the fingerprint recognition stage, the plurality of organic light-emitting units120may emit light in accordance with a first light-emitting unit array124, and the distance J of any two adjacent organic light-emitting units120in the first light-emitting unit array124may be greater than or equal to the minimum crosstalk distance L. The minimum crosstalk distance L is the maximum radius of a coverage region132at the fingerprint recognition layer21, in which the coverage region132is formed by the light emitted from any one of the plurality of organic light-emitting units120and then reflected to the fingerprint recognition layer21by the first surface of the cover plate14.

In one embodiment, the first substrate10may have an outer side far away from the cover glass14and an opposite inner side facing the cover glass14. The fingerprint recognition layer21may be disposed on the outer side of the first substrate10. The fingerprint recognition layer21may include a plurality of fingerprint recognition units211, and the plurality of fingerprint recognition units211may be disposed corresponding to the plurality of organic light-emitting units120.

The display module1may be configured as the light source for fingerprint recognition. In particular, the organic light-emitting unit120of the organic light-emitting layer12in the display module1may be configured as the light source for fingerprint recognition. When the user finger presses against the first surface of the cover plate14, the light emitted by the organic light-emitting unit120is incident onto the user finger after being transmitted through the first surface of the cover plate14, and then is reflected by the fingerprint of the user finger to form the fingerprint signal light. The fingerprint signal light is transmitted through the first surface of the cover plate14again, and then incident onto the fingerprint recognition unit211corresponding to the organic light-emitting unit120. The fingerprint recognition unit211that receives the fingerprint signal light generates an induction signal, according to which the fingerprint recognition circuit of the display panel performs the fingerprint recognition.

FIG. 29illustrates a crosstalk in an existing display panel. As shown inFIG. 29, when all the organic light-emitting units120emit light at the same time for fingerprint recognition, because the light emitted by the organic light-emitting unit120has a wide range of angular distribution, each fingerprint recognition unit211receives not only fingerprint signal light from the corresponding organic light-emitting units120, but also interference signals from other organic light-emitting units120, degrading the accuracy of the fingerprint recognition.

As a comparison, as shown inFIGS. 28a-28c, to improve the accuracy of the fingerprint recognition, at the fingerprint recognition stage, the plurality of organic light-emitting units120may emit light in accordance with a first light-emitting unit array124, and the distance J of any two adjacent organic light-emitting units120in the first light-emitting unit array124may be greater than or equal to the minimum crosstalk distance L.

Referring toFIGS. 28a-28b, the light emitted from the organic light-emitting unit120may be angularly distributed. The light emitted from the organic light-emitting unit120may be reflected by the first surface of the cover glass14to form the coverage region132on the fingerprint recognition layer21. That is, any fingerprint signal light emitted from the organic light-emitting unit120may be reflected by the first surface of the cover glass14and incident onto the coverage region132on the fingerprint recognition layer21. The maximum radius of the coverage region132may be the minimum crosstalk distance L.

The distance J of any two adjacent organic light-emitting units120in the first light-emitting unit array124may be configured to be greater than or equal to the minimum crosstalk distance L, such that in a plurality of turned-on organic light-emitting units120in the first light-emitting unit array124, the fingerprint signal light emitted from any one of the plurality of turned-on organic light-emitting units120may be prevented from being incident onto the fingerprint recognition unit211corresponding to other turned-on organic light-emitting units120. That is, the fingerprint recognition unit211, which is corresponding to any one of the plurality of turned-on organic light-emitting units120in the first light-emitting unit array124, may only receive the fingerprint signal light emitted from the corresponding turned-on organic light-emitting unit120.

Thus, in the display panel, the fingerprint recognition unit211, which is corresponding to any one of the plurality of turned-on organic light-emitting units120in the first light-emitting unit array124, may not receive any interference signals from other turned-on organic light-emitting units120. Accordingly, when the fingerprint recognition circuit of the display panel performs the fingerprint recognition based on the induction signal generated by the fingerprint recognition unit211, the accuracy the fingerprint recognition may be improved.

In the disclosed embodiments, the fingerprint signal light is defined as the reflected light formed by reflecting the light emitted from the organic light-emitting unit120by the fingerprint of the user finger, which is pressing the first surface of the cover plate14. As compared to the thickness of the display panel, the distance between the first surface of the cover plate14and the fingerprint of the user finger may be substantially small and, thus, the influence on the range of the coverage region132may be substantially small. Thus, the minimum crosstalk distance L is determined without taking the distance between the first surface of the cover plate14and the fingerprint of the user finger into account.

In addition, the radius L of the coverage region132is calculated based on the fact that the origin is the center point of the organic light-emitting unit120. However, the number of the organic light-emitting units120in the display panel is often substantially large and, accordingly, the size of the organic light-emitting unit120is substantially small. Thus, in the disclosed embodiments, the entire organic light-emitting unit120may be considered as the origin of the coverage region132and, accordingly, the radius L of the coverage region132may be calculated as the length from the edge of the organic light-emitting unit120to the edge of the coverage region132. That is, the size of the organic light-emitting unit120may not be taken into account when calculating the minimum crosstalk distance L.

It should be noted that, the minimum crosstalk distance L may be related to the thickness of the display panel, and the light emission angle of the organic light-emitting unit, etc., such that different display panels may have different values of the minimum crosstalk distance L. In another embodiment, when calculating the minimum crosstalk distance L, the size of the organic light-emitting unit120may have to be taken into account.

As described above, the light emitted from the organic light-emitting unit120may have an angular distribution. The minimum crosstalk distance L is the maximum radius of a coverage region132at the fingerprint recognition layer21, in which the coverage region132is formed by the light emitted from any one of the plurality of organic light-emitting units120and then reflected to the fingerprint recognition layer21by the first surface of the cover plate14. That is, the coverage region132on the fingerprint recognition layer21may be confined by the reflected light, which is formed by reflecting the light emitted from the edge of the organic light-emitting unit120and with the maximum emission angle onto the fingerprint recognition layer21. Then the light emitted from the organic light-emitting unit120and with any emission angle may be reflected to be within coverage region132.

FIG. 28dillustrates a detailed schematic view of another exemplary display panel inFIG. 28aconsistent with disclosed embodiments.

As shown inFIG. 28d, each organic light-emitting unit120may have an inner side far away from the first substrate10and an opposite outer side facing the first substrate10. A first electrode313, a light-emitting function layer311, and a second electrode314may be sequentially disposed on the inner side of the organic light-emitting unit120. One first electrode313, and the corresponding light-emitting function layer311and second electrode314together may form one organic light-emitting unit120.

In one embodiment, the organic light-emitting layer12may include organic light-emitting units of three different colors and, accordingly, one organic light-emitting unit120may include three organic light-emitting sub-units of different colors. When a signal is applied to the first electrode313and second electrode314, the light-emitting function layer311may emit light having an angular distribution. The fingerprint signal light may be substantially formed by specular reflection of the light emitted from the light-emitting function layer311, i.e., angle of reflection=angle of incidence.

Thus, L=tan θ*H1+tan θ*H2, where L is the minimum crosstalk distance and θ is the angle between the direction with a preset luminance and the direction perpendicular to the organic light-emitting unit120, H1is the distance between the first surface of the cover plate14and the light-emitting function layer311in the direction perpendicular to the display panel, and H2is the distance between the first surface of the cover plate14and the fingerprint recognition layer21in the direction perpendicular to the display panel. The preset luminance may be configured to be less than or equal to approximately 10% of the luminance in the direction perpendicular to the organic light-emitting layer311.

In the disclosed embodiments, the light emission angle (the angle with respect to the direction perpendicular to the organic light-emitting layer311) of the light emitted from the organic light-emitting unit120may be related to the luminance of the organic light-emitting unit120. The luminance is the subjective feeling of the light intensity, and the luminance in the direction perpendicular to the organic light-emitting layer311is defined as 100%. The lower the luminance is, the larger the light emission angle is.

When the luminance (unit: cd/m2) of the organic light-emitting unit120is less than or equal to 10%, the light intensity of the light emitted from the organic light-emitting unit120may be substantially low, and the light reflected by the first surface of the cover plate14may not cause a crosstalk in the fingerprint recognition unit211. Thus, in one embodiment, the light emission angle of the organic light-emitting unit120may be determined based on the critical luminance value of 10%.

The angle θ may be determined by measuring the luminance of the light emitted from the organic light-emitting unit120in the direction perpendicular to the organic light-emitting unit120(i.e., the light emission angle is zero), determining the light emission direction in which the emitted light has 10% luminance of the light having the zero light emission angle, and determining the angle θ according to an angel between the determined light emission direction and the direction perpendicular to the organic light-emitting unit120.

It should be noted that, organic light-emitting units in different display panels may have different light intensity and, accordingly, the preset luminance may also be different. In another embodiment, the preset luminance may be configured to approximately 12% or 9% of the luminance in the direction perpendicular to the organic light-emitting layer311. That is, in practical applications, the preset luminance may be determined according to various application scenarios, which is not limited by the present disclosure.

FIG. 28cillustrates a scanning diagram at a fingerprint recognition stage of another exemplary display panel inFIG. 28aconsistent with disclosed embodiments.

As shown inFIG. 28c, at the fingerprint recognition stage, the display panel may scan the display screen for fingerprint recognition. For example, in a first image frame, a plurality of organic light-emitting units120may be simultaneously turned on in accordance with the first light-emitting unit array124shown in the most left sub-figure inFIG. 28c, and the induction signal generated by the fingerprint recognition unit211corresponding to the organic light-emitting unit120may be recorded.

In a second image frame, the plurality of organic light-emitting units120simultaneously turned on in accordance with the first light-emitting unit array124shown in the most left sub-figure inFIG. 28cmay be displaced, i.e., a plurality of organic light-emitting units120may be simultaneously turned on in accordance with the first light-emitting unit array124shown in the middle sub-figure inFIG. 28c, and the corresponding induction signals may be recorded.

In a third image frame, the plurality of organic light-emitting units120simultaneously turned on in accordance with the first light-emitting unit array124shown in the middle sub-figure inFIG. 28cmay be displaced, i.e., a plurality of organic light-emitting units120may be simultaneously turned on in accordance with the first light-emitting unit array124shown in the most right sub-figure inFIG. 28c, and the corresponding induction signals may be recorded.

The organic light-emitting units120simultaneously turned on in accordance with the first light-emitting unit array124may keep being displaced, until all the organic light-emitting units120may be sequentially turned-on, and the fingerprint recognition is performed based on the corresponding induction signals received by the fingerprint recognition units211. Because the fingerprint recognition unit211does not receive any crosstalk signals, the fingerprint recognition accuracy of the display panel may be substantially high.

The first light-emitting unit array may be a smallest repeating unit composed of a plurality of organic light-emitting units that simultaneously emit light, and is not limited to a matrix formed by a plurality of organic light-emitting units that simultaneously emit light.

In the disclosed embodiments, at the fingerprint recognition stage, a plurality of organic light-emitting units120may be simultaneously turned on in accordance with the first light-emitting unit array124. The distance J of any two adjacent organic light-emitting units120in the first light-emitting unit array124may be configured to be greater than or equal to the minimum crosstalk distance L. The minimum crosstalk distance L may be defined as the maximum radius of the coverage region132at the fingerprint recognition layer21, in which the coverage region132is formed by the light emitted from any one of the plurality of organic light-emitting units120and then reflected to the fingerprint recognition layer21by the first surface of the cover plate14.

Thus, in a plurality of turned-on organic light-emitting units120in the first light-emitting unit array124, the fingerprint signal light emitted from any one of the plurality of turned-on organic light-emitting units120may be prevented from being incident onto the fingerprint recognition unit211corresponding to other turned-on organic light-emitting units120. That is, the fingerprint recognition unit211, which is corresponding to any one of the plurality of turned-on organic light-emitting units120in the first light-emitting unit array124, may only receive the fingerprint signal light emitted from the corresponding turned-on organic light-emitting unit120.

Thus, in the display panel, the fingerprint recognition unit211, which is corresponding to any one of the plurality of turned-on organic light-emitting units120in the first light-emitting unit array124, may not receive any interference signals from other turned-on organic light-emitting units120. Accordingly, when the fingerprint recognition circuit of the display panel performs the fingerprint recognition based on the induction signal generated by the fingerprint recognition unit211, the accuracy the fingerprint recognition may be improved.

It should be noted that the display panel shown inFIG. 28ais only one of the display panels provided by the present disclosure, and a variety of display panels having different configurations are provided in other embodiments of the present disclosure.

FIG. 30illustrates a schematic cross-sectional view of another exemplary display panel consistent with disclosed embodiments. The similarities betweenFIG. 30andFIG. 28amay not be repeated here, while certain difference may be explained.

As shown inFIG. 30, the first substrate10may have an inner side facing the cover glass14and an opposite outer side. A TFT array113, a fingerprint recognition layer21, and an organic light-emitting layer12may be disposed on the inner side of the first substrate10. The fingerprint recognition layer21may be disposed between the TFT array113and the organic light-emitting layer12. The fingerprint recognition layer21may be electrically insulated from the TFT array113and the organic light-emitting layer12, respectively.

The fingerprint recognition process of the display panel shown inFIG. 30may be similar to the fingerprint recognition process of the display panel shown inFIG. 28a, which is not repeated here. In particular, in the display panel shown inFIG. 30, through disposing the fingerprint recognition layer21between the TFT array113and the organic light-emitting layer12, the aperture ratio of the first electrode313in the organic light-emitting unit120in the organic light-emitting layer12may not be degraded. The arrangement of the fingerprint recognition units211may be determined according to various application scenarios, which is not limited by the present disclosure.

FIG. 31aillustrates a schematic cross-sectional view of another exemplary display panel consistent with disclosed embodiments.FIG. 31billustrates a schematic H1-H2sectional view of another exemplary display panel inFIG. 31aconsistent with disclosed embodiments. The similarities betweenFIGS. 31a-31bandFIG. 28amay not be repeated here, while certain difference may be explained.

As shown inFIGS. 31a-31b, the first substrate10may have an inner side facing the cover glass14and an opposite outer side. A TFT array113, a fingerprint recognition layer21, and an organic light-emitting layer12may be disposed on the inner side of the first substrate10. The organic light-emitting layer12may include a plurality of light-emitting regions120aand a plurality of non-light-emitting region120b, and the orthogonal projection of the fingerprint recognition layer21onto the display panel may be disposed in the non-light-emitting regions120bof the organic light-emitting layer12. The fingerprint recognition layer21may be disposed on the inner side of the first substrate10, and the fingerprint recognition layer21may be electrically insulated from the organic light-emitting layer12.

The fingerprint recognition process of the display panel shown inFIGS. 31a-31bmay be similar to the fingerprint recognition process of the display panel shown inFIG. 28a, which is not repeated here. In particular, in the display panel shown inFIGS. 31a-31b, the fingerprint recognition layer21may be disposed on the inner side of the first substrate10, through configuring the orthogonal projection of the fingerprint recognition layer21onto the display panel to be disposed in the non-light-emitting regions120bof the organic light-emitting layer12, the aperture ratio of the first electrode313in the organic light-emitting unit120in the organic light-emitting layer12may not be degraded.

FIG. 32aillustrates a schematic cross-sectional view of another exemplary display panel consistent with disclosed embodiments.FIG. 32billustrates a schematic11-12sectional view of another exemplary display panel inFIG. 32aconsistent with disclosed embodiments. The similarities betweenFIGS. 32a-32bandFIG. 28amay not be repeated here, while certain difference may be explained.

As shown inFIGS. 32a-32b, the display module1may further include an encapsulation glass140. The first substrate10may have an inner side facing the cover glass14and an opposite outer side, and the encapsulation glass140may be disposed on the inner side of the first substrate10. The encapsulation glass140may have an inner side facing the first substrate10and an opposite outer side, and the fingerprint recognition layer21may disposed on the inner side of the encapsulation glass140. The organic light-emitting layer12may be disposed between the first substrate10and the fingerprint recognition layer21. The organic light-emitting layer12may include a plurality of light-emitting regions120aand a plurality of non-light-emitting region120b, and the orthogonal projection of the fingerprint recognition layer21onto the display panel may be disposed in the non-light-emitting regions120bof the organic light-emitting layer12.

The fingerprint recognition process of the display panel shown inFIGS. 32a-32bmay be similar to the fingerprint recognition process of the display panel shown inFIG. 28a, which is not repeated here.

In particular, in the display panel shown inFIGS. 32a-32b, the display panel may be encapsulated by the encapsulation glass140, and the fingerprint recognition layer21may disposed on the inner side of the encapsulation glass140. Through configuring the orthogonal projection of the fingerprint recognition layer21onto the display panel to be disposed in the non-light-emitting regions120bof the organic light-emitting layer12, the aperture ratio of the display panel may not be degraded.

FIG. 33aillustrates a schematic cross-sectional view of another exemplary display panel consistent with disclosed embodiments.FIG. 33billustrates a schematic cross-sectional view of another exemplary display panel consistent with disclosed embodiments. The similarities betweenFIGS. 33a-33bandFIG. 28amay not be repeated here, while certain difference may be explained.

As shown inFIGS. 33a-33b, the display module1may further include an encapsulation layer16. The first substrate10may have an inner side facing the cover glass14and an opposite outer side, and the encapsulation layer16may be disposed on the inner side of the first substrate10. The organic light-emitting layer12may also be disposed on the inner side of the first substrate10.

The encapsulation layer16may have an inner side facing the first substrate10and an opposite outer side. In one embodiment, the fingerprint recognition layer21may disposed on the inner side of the encapsulation layer16, as shown inFIG. 33a. In another embodiment, the fingerprint recognition layer21may disposed on the outer side of the encapsulation layer16, as shown inFIG. 32b.

FIG. 33cillustrates a schematic top view of exemplary display panels inFIG. 33aandFIG. 33bconsistent with disclosed embodiments. As shown inFIG. 33c, the organic light-emitting layer12may include a plurality of light-emitting regions120aand a plurality of non-light-emitting region120b, and the orthogonal projection of the fingerprint recognition layer21onto the display panel may be disposed in the non-light-emitting regions120bof the organic light-emitting layer12.

The fingerprint recognition process of the display panel shown inFIGS. 33a-33cmay be similar to the fingerprint recognition process of the display panel shown inFIG. 28a, which is not repeated here.

In particular, in the display panel shown inFIGS. 33a-33b, the display panel may be encapsulated by the encapsulation layer16, and the fingerprint recognition layer21may disposed on the inner side or the outer side of the encapsulation layer16. Through configuring the orthogonal projection of the fingerprint recognition layer21onto the display panel to be disposed in the non-light-emitting regions120bof the organic light-emitting layer12, the aperture ratio of the display panel may not be degraded.

It should be noted that, the display panel may read the fingerprint information by an image scanning method. When scanning a first image frame, a certain number of the organic light-emitting units120in the organic light-emitting layer12may emit light in accordance with the first light-emitting array124, and the fingerprint information detected by the fingerprint recognition units corresponding to the turned-on organic light-emitting units120. When scanning a second image frame, the certain number of the organic light-emitting units120emitting light may be shifted. The certain number of the organic light-emitting units120emitting light may be sequentially shifted until all the organic light-emitting units120in the organic light-emitting layer12are turned on through scanning a plurality of image frames.

The display panel performs the fingerprint information by scanning a plurality of image frames, when the number of the organic light-emitting units120which are turned-on in one image frame is smaller, the number of the image frames for completely reading the fingerprint information may be larger, and the time for completely reading the fingerprint information may be longer.

For example, when the display panel reads the fingerprint information using the image scanning method shown inFIG. 34a, and the number of the organic light-emitting units120emitting light at the same time in each image frame (11*10 organic light-emitting units) is nine, then at least 12 image frames (11*10/9=12.3) may have to be scanned to completely read the fingerprint information detected by the fingerprint recognition units211of all the organic light-emitting units120, given that the reading time of the fingerprint information for each image frame is fixed.

To reduce the time required to read the fingerprint information, in one embodiment, a plurality of organic light-emitting units120in the first light-emitting array124as shown inFIG. 34bmay form a plurality of patterns, in which the pattern125with the smallest area may have each angle unequal to 90°.

As compared toFIG. 34a, the distance J between any two adjacent light-emitting organic units120in the first light-emitting array124shown inFIG. 34bmay be reduced and, thus, the number of the turned-on organic light-emitting units120in each image frame may be increased. For example, the number of the organic light-emitting units120emitting light at the same time in each image frame (11*10 organic light-emitting units) may become twelve, then at most 10 image frames (11*10/12=10) may have to be scanned to completely read the fingerprint information detected by the fingerprint recognition units211of all the organic light-emitting units120, given that the reading time of the fingerprint information for each image frame is fixed.

Through configuring a plurality of organic light-emitting units120in the first light-emitting array124to form a plurality of patterns and configuring the pattern125with the smallest area to have each angle unequal to 90°, the number of the turned-on organic light-emitting units120in each image frame may be increased without introducing any crosstalk. Accordingly, the time for completely reading the fingerprint information may be significantly reduced.

For example, in one embodiment, as shown inFIG. 35a, the first light-emitting unit array124may be a pentagonal light-emitting unit array124, which may include an organic light-emitting unit120disposed in the center of the pentagonal light-emitting unit array124(called as a central organic light-emitting unit) and five edge organic light-emitting units120disposed at the edge of the pentagonal light-emitting unit array124(called as edge organic light-emitting units). A plurality of organic light-emitting units120in the first light-emitting array124may form a plurality of patterns, in which the pattern125with the smallest area may have each angle unequal to 90°. The pentagonal light-emitting unit array124may increase the number of the turned-on organic light-emitting units120in each image frame without introducing any crosstalk. Accordingly, the time for completely reading the fingerprint information may be significantly reduced.

In another embodiment, as shown inFIG. 35b, the first light-emitting unit array124may be a hexagonal light-emitting unit array124, which may include a central organic light-emitting unit120and six edge organic light-emitting units120. Similarly, the hexagonal light-emitting unit array124may increase the number of the turned-on organic light-emitting units120in each image frame without introducing any crosstalk. Accordingly, the time for completely reading the fingerprint information may be significantly reduced.

In another embodiment, as shown inFIG. 35c, the first light-emitting unit array124may include a first light-emitting unit row124aand a second light-emitting unit row124bdisposed with an interval. In particular, any organic light-emitting units124in the first light-emitting unit row124aand any organic light-emitting units124in the second light-emitting unit row124bmay not be disposed in a same column.

Through configuring any organic light-emitting units124in the first light-emitting unit row124aand any organic light-emitting units124in the second light-emitting unit row124bto be not disposed in a same column, the number of the turned-on organic light-emitting units120in each image frame may be increased without introducing any crosstalk. Accordingly, the time for completely reading the fingerprint information may be significantly reduced. For example, the number of the organic light-emitting units120emitting light at the same time in each image frame (11*10 organic light-emitting units) may be twelve, then at most 10 image frames (11*10/12=10) may have to be scanned to completely read the fingerprint information detected by the fingerprint recognition units211of all the organic light-emitting units120. Thus, the time for completely reading the fingerprint information may be significantly reduced.

For any of the first light-emitting unit array124provided in any of the disclosed embodiments, the distance J of any two adjacent organic light-emitting units120in the first light-emitting unit array124may be configured to be greater than or equal to the minimum crosstalk distance L. Thus, on one hand, in the display panel, the fingerprint recognition unit211, which is corresponding to any one of the plurality of turned-on organic light-emitting units120in the first light-emitting unit array124, may not receive any interference signals from other turned-on organic light-emitting units120. Accordingly, the accuracy the fingerprint recognition may be improved. On the other hand, the number of the turned-on organic light-emitting units120in each image frame may be increased and, thus, the time for completely reading the fingerprint information may be significantly reduced, and the reading efficiency of the fingerprint information may be improved.

For any of the first light-emitting unit array124provided in any of the disclosed embodiments, in one embodiment, as shown inFIG. 35b, a vertical distance between any two adjacent organic light-emitting units120may be configured to satisfy at least one of the following conditions: (1) a vertical distance C1between any two adjacent organic light-emitting units120which are not disposed in the same row may be configured to be greater than or equal to the minimum crosstalk distance L; and (2) a vertical distance C2between any two adjacent organic light-emitting units120which are not disposed in the same column may be configured to be greater than or equal to the minimum crosstalk distance L.

Through configuring the first light-emitting unit array124, on one hand, in the display panel, the fingerprint recognition unit211, which is corresponding to any one of the plurality of turned-on organic light-emitting units120in the first light-emitting unit array124, may not receive any interference signals from other turned-on organic light-emitting units120. Accordingly, the accuracy the fingerprint recognition may be improved. On the other hand, the number of the turned-on organic light-emitting units120in each image frame may be increased and, thus, the time for completely reading the fingerprint information may be significantly reduced, and the reading efficiency of the fingerprint information may be improved.

The fingerprint reading efficiency of the display panel is further explained by taking a square array scanning method and a hexagonal array scanning method as an example.

The distance between the two adjacent turned-on organic light-emitting units120is configured to be greater than or equal to the distance between at least 20 organic light-emitting units120(the distance between the centers of two organic light-emitting units120), and the distance between 20 organic light-emitting units120is defined as 20P.

FIG. 36aillustrates an exemplary square array scanning method of an exemplary display panel consistent with disclosed embodiments. As shown inFIG. 36a, the coordinates of the tuned-on organic light-emitting unit is defined as (row, column), and the coordinates of the first organic light-emitting unit120in the upper left corner inFIG. 36ais defined as (1,1). Then the coordinates of the turned-on organic light-emitting units120in the first row are respectively (1,1), (1,21), (1,41), . . . , and the coordinates of the turned-on organic light-emitting units120in the second row are respectively (21,1), (21,21), (21,41), . . . , and the coordinates of the turned-on organic light-emitting units120in the third row are respectively (41,1), (41,21), (41,41), . . . , and so on. That is, (1,1), (1,21), (1,41), . . . , (21,1), (21,21), (21,41), . . . , and (41, 1), (41, 21) (41,41), . . . , and so on, are the coordinates of all the organic light-emitting units120which are simultaneously turned-on in one image frame.

Provided that each of the turned-on organic light-emitting units120is a center point, the organic light-emitting layer12of the display panel may be vertically and horizontally divided into a plurality of identical bright regions121B each having a same size. Each bright region121B may include a turned-on organic light-emitting unit120and a plurality of turned-off organic light-emitting units120A surrounding the turned-on organic light-emitting unit120. It should be noted that, the turned-on organic light-emitting unit120, which is disposed at the edge of the organic light-emitting layer12, may correspond to a region of the organic light-emitting layer12which is only a part of the bright region corresponding to the turned-on organic light-emitting unit120.

For example, the turned-on organic light-emitting unit120(21,41) may correspond to a bright region121B including four turned-off organic light-emitting units120A, and the coordinates of the four turned-off organic light-emitting units120A are (11,31), (11, 51), (31,31) and (31,51), respectively. The bright region121B may have a length of 20P and a width of 20P, i.e., the number of the organic light-emitting units forming the bright spot region121B may be 20*20=400. However, the bright region121B may only have one turned-on organic light-emitting unit120(21,41), i.e., every 400 organic light-emitting units120may only have one turned-on organic light-emitting unit120. Thus, the density of the turned-on organic light-emitting unit120in the bright region121B may be 1/400.

Because the organic light-emitting layer12of the display panel is divided into a plurality of identical bright regions121B, the density of the turned-on organic light-emitting unit120in each image frame may be 1/400. Thus, to sequentially turn on all the organic light-emitting units120in the display panel, 400 (20*20) image frames may have to be scanned.FIG. 36aonly shows some of the organic light-emitting units120which are simultaneously turned on and their coordinates, and four turned-off organic light-emitting units120A in the bright region121B and their coordinates.

FIG. 36billustrates a schematic view of a hexagonal array scanning method of an exemplary display panel consistent with disclosed embodiments. The similarities betweenFIG. 36aandFIG. 36bare not repeated here, while certain difference may be explained.

As shown inFIG. 36b, the coordinates of the tuned-on organic light-emitting unit is defined as (row, column), and the coordinates of the first organic light-emitting unit120in the upper left corner inFIG. 36bis defined as (1,1). The distance J between any two adjacent turned-on organic light-emitting units120is configured to be the distance between 20 organic light-emitting units120(i.e., 20P). The distance J1from a row including the central organic light-emitting unit120to the edge organic light-emitting unit120disposed in a row different from the central organic light-emitting unit120is 10P√{square root over (3)}≈18P. The distance J2from a column including the central organic light-emitting unit120to the edge organic light-emitting unit120disposed in a row different from the central organic light-emitting unit120is 10P.

When some organic light-emitting units120are turned on and the distance between two adjacent turned-on organic light-emitting units120in the same row is 20P, the row spacing of the turned-on organic light-emitting units120disposed in different rows may be reduced from 20P to 18P. Thus, the distance from the central organic light-emitting unit120to the edge organic light-emitting unit120disposed in a row different from the central organic light-emitting unit120may be √{square root over ((10P)2+(18P)2)}≈20.59P>20P, meeting the requirements to avoid a crosstalk.

Provided that each of the turned-on organic light-emitting units120is a center point, the organic light-emitting layer12of the display panel may be vertically and horizontally divided into a plurality of identical bright regions121B each having a same size. Each bright region121B may include a turned-on organic light-emitting unit120and a plurality of turned-off organic light-emitting units120A surrounding the turned-on organic light-emitting unit120. It should be noted that, the turned-on organic light-emitting unit120, which is disposed at the edge of the organic light-emitting layer12, may correspond to a region of the organic light-emitting layer12which is only a part of the bright region corresponding to the turned-on organic light-emitting unit120.

For example, the turned-on organic light-emitting unit120(19,51) may correspond to a bright region121B including four turned-off organic light-emitting units120A, and the coordinates of the four turned-off organic light-emitting units120A are (10,41), (10,61), (28,41) and (28,61), respectively. The bright region121B may have a length of 20P in the row direction and a width of 18P in the column direction, i.e., the number of the organic light-emitting units forming the bright spot region121B may be 20*18=360. However, the bright region121B may only have one turned-on organic light-emitting unit120(19,51), i.e., every 360 organic light-emitting units120may only have one turned-on organic light-emitting unit120. Thus, the density of the turned-on organic light-emitting unit120in the bright region121B may be 1/360.

Because the organic light-emitting layer12of the display panel are divided into a plurality of identical bright regions121B, the density of the turned-on organic light-emitting unit120in each image frame may be 1/360. Thus, to sequentially turn on all the organic light-emitting units120in the display panel, 360 (20*18) image frames may have to be scanned.FIG. 36bonly shows some of the organic light-emitting units120which are simultaneously turned on and their coordinates, and four turned-off organic light-emitting units120A in the bright region121B and their coordinates.

According to the above discussion of the scanning methods shown inFIGS. 36a-36b, the hexagonal array scanning method of the display panelFIG. 36bmay outperform the square array scanning method of the display panelFIG. 36a, in terms of the number of the image frames to be scanned for sequentially turning on all the organic light-emitting units120in the display panel.

Further, the present disclosure also provides a fingerprint recognition method for exemplary display panels shown inFIGS. 28ato 28dandFIGS. 30 to 35c. As shown inFIGS. 28ato 28dandFIGS. 30 to 35c, the display panel may comprise a display module1and a fingerprint recognition module2. The display module1may comprise a first substrate10, an organic light-emitting layer12disposed on the first substrate10, and a cover glass14. The organic light-emitting layer12may have an inner side far away from the first substrate10and an opposite outer side facing the first substrate10. The cover glass14may be disposed on the inner side of the organic light-emitting layer12.

The organic light-emitting layer12may include a plurality of organic light-emitting units120. The fingerprint recognition module2may include a fingerprint recognition layer21. The cover glass14may have a first surface far away from the first substrate10and an opposite second surface facing the first substrate10. The light-exiting surface of the display panel may be defined as the first surface of the cover glass14.

FIG. 37illustrates a flowchart of an exemplary display panel fingerprint recognition method consistent with disclosed embodiments. As shown inFIG. 37, the fingerprint recognition method for the display panel may comprise the following steps.

At the fingerprint recognition stage, a plurality of organic light-emitting units are controlled to emit light in accordance with a first light-emitting unit array (S310). The distance of any two adjacent organic light-emitting units in the first light-emitting unit array may be greater than or equal to the minimum crosstalk distance. The minimum crosstalk distance is the maximum radius of a coverage region at the fingerprint recognition layer, in which the coverage region is formed by the light emitted from any one of the plurality of organic light-emitting units and then reflected to the fingerprint recognition layer by the first surface of the cover plate.

The fingerprint recognition layer performs fingerprint recognition based on the light reflected to the fingerprint recognition unit by the touch object, which is arranged on the first surface of the cover plate (S320). In the disclosed embodiment, the touch object may be selected as a user finger.

In the disclosed embodiments, the display panel may perform the fingerprint recognition by an image scanning method, and in each image frame, each organic light-emitting unit may emit light in accordance with the first light-emitting unit array. In particular, the distance of any adjacent organic light-emitting units in the first light-emitting unit array may be configured to be greater than or equal to the minimum crosstalk distance, Thus, in a plurality of turned-on organic light-emitting units in the first light-emitting unit array, the fingerprint signal light emitted from any one of the plurality of turned-on organic light-emitting units may be prevented from being incident onto the fingerprint recognition unit corresponding to other turned-on organic light-emitting units.

That is, the fingerprint recognition unit, which is corresponding to any one of the plurality of turned-on organic light-emitting units in the first light-emitting unit array, may only receive the fingerprint signal light emitted from the corresponding turned-on organic light-emitting unit, i.e., may not receive any interference signals from other turned-on organic light-emitting units120. Accordingly, the induction signal generated by the fingerprint recognition unit may accurately indicate the light reflection of the outgoing light of the corresponding organic light-emitting unit at the fingerprint of the user finger. Thus, the accuracy of the fingerprint recognition may be improved.

The present disclosure also provides a display device comprising any one of the disclosed display panels.FIG. 38illustrates an exemplary display device consistent with disclosed embodiments. As shown inFIG. 38, the display device may comprise a display panel200, which may include any one of the disclosed display panels. The display device100may be a mobile phone, a computer, a television, and a smart wearable display device, which is not limited by the present disclosure.

In the disclosed embodiments, the light-exiting surface of the display module is disposed on the outer side of the first polarizer, the fingerprint recognition module is disposed on the outer side of the first substrate. The fingerprint recognition module comprises the fingerprint recognition layer and the second polarizer disposed on the inner side of the fingerprint recognition layer. At the fingerprint recognition stage, the light emitted from the inner side of the first polarizer is reflected by the touch object (such as a user finger) to form the fingerprint signa light, during which the first polarizer is engaged with the second polarizer, such that the fingerprint signal light may be transmitted through the first polarizer and the second polarizer without a light intensity loss.

Meanwhile, before the light (i.e., the fingerprint noise light) which is not reflected by the touch object is incident onto the fingerprint recognition layer, the second polarizer at least reduces the light intensity of the fingerprint noise light. Thus, the crosstalk caused by the fingerprint noise may be suppressed, the signal-to-noise ratio may be improved, and the accuracy of the fingerprint recognition module may be improved.

Various embodiments have been described to illustrate the operation principles and exemplary implementations. It should be understood by those skilled in the art that the present disclosure is not limited to the specific embodiments described herein and that various other obvious changes, rearrangements, and substitutions will occur to those skilled in the art without departing from the scope of the disclosure. Thus, while the present disclosure has been described in detail with reference to the above described embodiments, the present disclosure is not limited to the above described embodiments, but may be embodied in other equivalent forms without departing from the scope of the present disclosure, which is determined by the appended claims.