Display panel and method for preparing photosensitive module thereof

Abstract

An embodiment of the present application provides a method for preparing a display panel and a photosensitive module thereof. The display panel includes a base substrate and a photosensitive module; a fingerprint recognition module is disposed within the base substrate; the photosensitive module is disposed on the light-emitting side of the base substrate and includes: a base layer, a lens array layer, and a light-shielding layer, the lens array layer and the light-shielding layer being disposed on either side of the base layer, respectively, with the light-shielding layer disposed proximal to the base substrate; the light-shielding layer is provided with light-transmitting holes corresponding one-to-one with the lens array layer, and the fingerprint recognition module collects and recognizes fingerprint images located on the light-emitting side of the base substrate through the light-transmitting holes. Providing the light-transmitting holes in the light-shielding layer prevents stray light outside the display panel from entering the fingerprint recognition module and affecting the fingerprint recognition effect.

Description

Technical Field

[0001] The present application relates to the field of display technology, and in particular to a method for preparing a display panel and a photosensitive module thereof. Background Art

[0002] Information security has always been a key concern. For example, bank accounts, secure payments, door locks, and safes all require verification before they can be opened. Early security verification methods primarily relied on multi-digit passwords, but this method was cumbersome, easy to forget, and vulnerable to being snooped on and stolen, posing a serious security risk. To address this, biometric identification methods such as iris recognition, fingerprint recognition, and 3D facial recognition have gradually emerged. These biometrics are unique and convenient to use, making them a mainstream market, with fingerprint recognition being the most widely used.

[0003] Portable devices like smartphones and tablets have become indispensable for communication, interaction, learning, entertainment, and shopping. Unlocking the screen and making electronic payments require identity verification, making fingerprint recognition a must-have technology for these devices. Fingerprint recognition methods for full-screen portable devices include optical and ultrasonic fingerprint recognition. Optical fingerprint recognition offers advantages in cost and energy savings, leading to its widespread adoption. Currently, most optical fingerprint recognition systems only support single-finger unlocking and are located near the phone's bottom bezel, resulting in a poor user experience.

[0004] Therefore, improvements are urgently needed to address the defects in the prior art. Summary of the Invention

[0005] The embodiments of the present application provide a display panel and a method for manufacturing a photosensitive module of the display panel to improve the current problem of low fingerprint recognition accuracy and small fingerprint recognition area in display panels.

[0006] An embodiment of the present application provides a display panel, comprising: a base substrate, in which a fingerprint recognition module is disposed; a photosensitive module, disposed on the light-emitting side of the base substrate, comprising: a base layer, a lens array layer, and a light-shielding layer, wherein the lens array layer and the light-shielding layer are respectively disposed on either side of the base layer, and the light-shielding layer is disposed close to the base substrate; wherein the light-shielding layer is provided with light-transmitting holes corresponding one-to-one to the lens array layer, and the fingerprint recognition module collects and recognizes a fingerprint image located on the light-emitting side of the base substrate through the light-transmitting holes.

[0007] Optionally, in an embodiment of the present application, the fingerprint recognition module array is disposed in the base substrate, and one fingerprint recognition module is disposed at least corresponding to one light-transmitting hole.

[0008] Optionally, in an embodiment of the present application, the lens array layer includes a plurality of lenses, and the focal length of each lens is greater than the thickness of the base layer and less than the sum of the thicknesses of the base layer and the light-shielding layer.

[0009] Optionally, in an embodiment of the present application, the focused spot size of a single lens is slightly smaller than the size of the light-transmitting hole; the focused spot size of a single lens is in a range of 2 μm to 15 μm.

[0010] Optionally, in an embodiment of the present application, the photosensitive module further includes a protective layer, which is arranged on a side of the lens array layer away from the base layer and covers the lens array layer.

[0011] Optionally, in one embodiment of the present application, the lens array layer is arranged in a quadrilateral or hexagonal manner.

[0012] Optionally, in an embodiment of the present application, the light shielding layer includes a black positive photoresist, and the black positive photoresist contains a black light absorbing substance.

[0013] Optionally, in one embodiment of the present application, an optical adhesive layer is further included, wherein the optical adhesive layer is disposed between the base substrate and the photosensitive module and covers the light-transmitting hole.

[0014] Correspondingly, an embodiment of the present application also provides a method for preparing the photosensitive module of the display panel described in the above embodiment, comprising the following steps: providing a base layer; preparing a lens array layer on one side of the base layer; coating black positive photoresist on the other side of the base layer to form a light-shielding layer; exposing the light-shielding layer using a micro-focusing method on the side of the lens array layer away from the light-shielding layer, and developing and removing the black positive photoresist in the exposed area to form a light-transmitting hole.

[0015] Optionally, in an embodiment of the present application, the method for preparing the photosensitive module further includes the following steps: after preparing the lens array layer, depositing a protective layer on the lens array layer; after forming the light-transmitting hole, removing the protective layer.

[0016] The present embodiment provides a display panel in which the lens array layer is configured to more closely focus the light reflected by the fingerprint, resulting in better fingerprint recognition. The light-shielding layer reduces interference light entering the fingerprint recognition module, improving fingerprint recognition sensitivity. The light-transmitting holes provided in the light-shielding layer prevent stray light from outside the display panel from entering the fingerprint recognition module and affecting fingerprint recognition. Furthermore, the photosensitive module and the fingerprint recognition module are disposed in the spacer between the pixel areas of the display panel, thereby not affecting normal display. This allows for simultaneous multi-finger recognition over a large display area, resulting in higher fingerprint unlocking security and better fingerprint recognition results.

[0017] Furthermore, by setting up one fingerprint recognition module corresponding to multiple light-transmitting holes, the size of the fingerprint recognition module can be ensured to be larger, thereby reducing the requirements for the lens array layer and its alignment accuracy, which is conducive to large-scale mass production; and under the premise that the fingerprint recognition resolution meets the requirements, the size of a single fingerprint recognition module and the pixel size of the display panel are quite different, which is conducive to reducing the interference of moiré patterns caused by the periodicity of the pixel display of the display panel and the recognition method of the fingerprint recognition module, thereby improving the fingerprint recognition accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 Schematic diagram of the three-dimensional cross-sectional structure of the display panel provided in the embodiment of the present application Figure 1 ;

[0020] Figure 2 Schematic diagram of the three-dimensional cross-sectional structure of the display panel provided in the embodiment of the present application Figure 2 ;

[0021] Figure 3 A schematic diagram of the arrangement of the lens array layer of the display panel provided in an embodiment of the present application;

[0022] Figure 4 A schematic flow chart of a method for preparing the photosensitive module of the display panel provided in an embodiment of the present application;

[0023] Figures 5 to 10 This is a schematic structural diagram of each step in the method for preparing the photosensitive module of the display panel provided in an embodiment of the present application.

[0024] Description of main reference numerals:

[0025] DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present application. In addition, it should be understood that the specific embodiments described herein are only used to illustrate and explain the present application, and are not used to limit the present application. In the present application, unless otherwise specified, the directional words used, such as "up", "down", "left" and "right", can be the directions of the actual use or working state of the device, can also be the directions of the drawings with reference to the drawings, or can refer to two relative directions; while "inside" and "outside" refer to the outline of the device.

[0027] See also Figures 1 to 2 The embodiment of the present application provides a display panel 10, comprising a base substrate 100, a photosensitive module 200 and an optical adhesive layer 300; a fingerprint recognition module 110 is provided in the base substrate 100; the photosensitive module 200 is provided on the light-emitting side of the base substrate 100, and comprises: a base layer 210, a lens array layer 220, a light shielding layer 230 and a protective layer 240, the lens array layer 220 and the light shielding layer 230 are respectively provided on both sides of the base layer 210, and the light shielding layer 230 is close to the base substrate 1 00 is set, the protective layer 240 is set on the side of the lens array layer 220 away from the base layer 210, and covers the lens array layer 220; the light-shielding layer 230 is provided with light-transmitting holes 231 corresponding to the lens array layer 220 one by one, and the fingerprint recognition module 110 collects and recognizes the fingerprint image located on the light-emitting side of the base substrate 100 through the light-transmitting holes 231; the optical adhesive layer 300 is set between the base substrate 100 and the photosensitive module 200, and covers the light-transmitting holes 231.

[0028] In the display panel 10 of the present application, when a user places a finger on the display area of ​​the display panel 10, light emitted by the display panel 10 is reflected by the fingerprint. The reflected light is converged by the lens array layer 220 and passes through the light-transmitting holes 231 to the fingerprint recognition module 110. The fingerprint recognition module 110 recognizes the fingerprint image based on the light emitted from each light-transmitting hole 231. The protective layer 240 can absorb stray light from the ambient light to achieve preliminary filtering of the light entering the lens array layer 220, for example, by absorbing infrared light from the ambient light. The provision of the lens array layer 220 makes the light reflected by the fingerprint more concentrated, thereby improving the recognition effect. The light-shielding layer 230 can reduce interfering light (such as fingerprint reflected light at a large angle or ambient light) entering the fingerprint recognition module 110, thereby improving the fingerprint recognition sensitivity. The provision of the light-transmitting holes 231 on the light-shielding layer 230 can prevent stray light outside the display panel 10 from entering the fingerprint recognition module 110 and affecting the fingerprint recognition effect. It can be understood that the photosensitive module 200 and the fingerprint recognition module 110 are arranged in the spacing area between the pixel areas of the display panel 10, so as not to affect the normal display, and can realize large-area recognition in the display area and achieve better fingerprint recognition effect.

[0029] In order to enable the fingerprint recognition module 110 to recognize a complete fingerprint image, the distribution of the light-transmitting holes 231 and the lens array layer 220 should satisfy the requirement that when a finger is placed in the display area of ​​the display panel 10, the lens array layer 220 in the area where the finger is located can ensure that the light reflected from each position of the finger can pass through the lens array layer 220 and the light-transmitting holes 231 to reach the fingerprint recognition module 110. Specifically, the fingerprint recognition modules 110 are arrayed in the base substrate 100, and one fingerprint recognition module 110 corresponds to at least one light-transmitting hole 231. Figure 2 As shown, preferably, one fingerprint recognition module 110 is provided corresponding to a plurality of light-transmitting holes 231, which can ensure that the size of the fingerprint recognition module 110 is larger, thereby reducing the requirements for the alignment accuracy of the lens array layer 220 and the lens array layer 220, which is conducive to large-scale mass production; and under the premise that the fingerprint recognition resolution meets the requirements, the size of a single fingerprint recognition module 110 and the pixel size of the display panel 10 are quite different, which is conducive to reducing the interference of moiré caused by the periodicity of the pixel display of the display panel 10 and the recognition method of the fingerprint recognition module 110, thereby improving the fingerprint recognition accuracy.

[0030] The fingerprint recognition module 110 described in this application may include a photoelectric sensor and an image processor. The photoelectric sensor is used to convert the received light into an electrical signal and send it to the image processor. The image processor calculates the fingerprint image corresponding to each focusing lens based on the received electrical signal and further synthesizes a complete fingerprint image. The fingerprint recognition module 110 can be set on one side of the light-emitting surface of the display panel 10. In this case, the fingerprint recognition module 110 can be integrated into the drive circuit (such as placed in the thin film transistor layer) or integrated into other film layers of the display panel 10. It should be noted that when the fingerprint recognition module 110 is integrated into the drive circuit, the display drive and the fingerprint drive can share a drive chip. By setting the fingerprint recognition module 110 on one side of the light-emitting surface of the display panel 10, the fingerprint recognition module 110 can be integrated with the film layer structure of the display panel 10, which is conducive to reducing the thickness of the display panel 10, the overall thickness is lower, and the integration is better.

[0031] In the present application, the lens array layer 220 includes a plurality of lenses 221. The focal length of each lens 221 is greater than the thickness of the base layer 210 and less than the sum of the thicknesses of the base layer 210 and the light shielding layer 230. In other words, the focused light spot of each lens 221 is located at the position of the corresponding light-transmitting hole 231, so that after being focused by the lens 221, as much light as possible can pass through the light-transmitting hole 231, thereby improving the fingerprint recognition effect. Preferably, the size of a single lens 221 ranges from 10 μm to 100 μm, for example, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, and 90 μm. The focused spot size of a single lens 221 is slightly smaller than the size of the light-transmitting hole 231. The focused spot size of a single lens 221 ranges from 2 μm to 15 μm, for example, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, and 14 μm. This configuration ensures that the light focused by the lens 221 can fully pass through the light-transmitting hole 231, while preventing external stray light from passing through the light-transmitting hole 231 and affecting the fingerprint recognition effect.

[0032] See also Figure 3 , the lens array layer 220 is arranged in a quadrilateral or hexagonal manner ( Figure 3 In other words, the cross-sectional shape of a single lens 221 is preferably a quadrilateral or a hexagon. This shape arrangement enables the duty cycle of the lens array layer 220 to approach 100%, thereby increasing the transmittance of the lens array layer 220 at each position of the finger, thereby improving the fingerprint recognition effect.

[0033] In the present application, the light-shielding layer 230 comprises a black positive photoresist containing a black light-absorbing material. Preferably, the thickness of the light-shielding layer 230 ranges from 1 μm to 5 μm. The light-shielding layer 230 has a cutoff performance for visible and infrared light of at least OD2, meaning a transmittance of less than or equal to 1%. In other words, the light-shielding layer 230 has an absorptivity greater than or equal to 99% for visible and infrared light. The black light-absorbing material is selected from the group consisting of carbon, carbide, carbonitride, and sulfide.

[0034] In the present application, the optical adhesive layer 300 is selected from one of solid optical transparent adhesive, high transmittance pressure-sensitive adhesive or transparent hot melt adhesive. The base substrate 100 can be bonded to the photosensitive module 200 through the optical adhesive layer 300, thereby improving the stability of the photosensitive module 200. Obviously, the flatness of the photosensitive module 200 after bonding with the optical adhesive layer 300 is higher, which can reduce the optical distortion caused by the wave of the film material and enhance the accuracy of its image recognition. Since the optical adhesive layer 300 covers the light-transmitting hole 231, if the thickness of the optical adhesive layer 300 is too thin, it will result in loose bonding, and if it is too thick, it will result in signal light loss or crosstalk. Preferably, the thickness of the optical adhesive layer 300 is in the range of 10μm to 20μm. This arrangement can ensure that the optical adhesive layer 300 covers the light-transmitting holes 231, that is, fills the light-transmitting holes 231 in the light-shielding layer 230, and prevents the light reflected by the lens array layer 220 at each position of the finger from being significantly refracted when passing through the base layer 210 due to the large difference in the light propagation path between the lens array layer 220 and the light-transmitting holes 231, thereby improving the recognition accuracy of the fingerprint recognition module 110.

[0035] See also Figures 4 to 10 Accordingly, the embodiment of the present application further provides a method for preparing the photosensitive module 200 of the display panel 10 described in any of the above embodiments, comprising the following steps:

[0036] like Figure 4 and Figure 5 As shown, step S1: providing a base layer 210 .

[0037] like Figure 4 and Figure 6 As shown, step S2: preparing a lens array layer 220 on one side of the base layer 210; the lens array layer 220 includes a plurality of lenses 221, and the plurality of lenses 221 are arranged in a quadrilateral or hexagonal manner.

[0038] like Figure 4 and Figure 7As shown, step S3: depositing a protection layer 240 on the lens array layer 220 to protect the lens array layer 220 .

[0039] like Figure 4 and Figure 8 As shown, step S4: coating a black positive photoresist on the other side of the base layer 210 to form a light shielding layer 230 .

[0040] like Figure 4 and Figure 9 As shown, step S5: exposing the light-shielding layer 230 using a micro-focusing method on the side of the lens array layer 220 away from the light-shielding layer 230, and developing and removing the black positive photoresist in the exposed area to form light-transmitting holes 231. Specifically, UV light is irradiated on the side of the lens array layer 220 away from the light-shielding layer 230. Within a certain focal length range, the UV light is focused on the black positive photoresist directly below the lens array layer 220. After a certain period of time, the black positive photoresist directly below the microlenses is cleaned through development, while the black positive photoresist at other locations remains, thus forming the light-transmitting holes 231. The UV light is collimated during the irradiation process to ensure that the light-transmitting holes 231 are evenly distributed.

[0041] like Figure 4 and Figure 10 As shown, step S6: removing the protective layer 240.

[0042] It can be understood that the photosensitive module 200 prepared by the preparation method of the photosensitive module 200 described in this application does not require the use of a photomask, and the relative position of the lens array layer 220 and the light-transmitting hole 231 is accurate, requiring no secondary alignment, and the alignment accuracy with the fingerprint recognition module 110 in the base substrate 100 is low, making it suitable for large-scale production and having lower process costs. The protective layer 240 plays a protective role for the lens array layer 220 during the preparation of the photosensitive module 200, and can absorb stray light in the ambient light to achieve preliminary filtering of light entering the lens array layer 220; in one embodiment, when the photosensitive module 200 is aligned and bonded to the base substrate 100, removing the protective layer 240 can further thin the display panel and improve the transmittance of the photosensitive module 200. Therefore, the protective layer 240 described in this application can be considered for removal based on actual usage, and this application will not be repeated.

[0043] The display panel 10 described in this application can be applied to any product or component with a display function, such as a mobile phone, tablet computer, television, monitor, laptop computer, digital photo frame, or navigation system. Other essential components of the display panel 10 are well understood by those skilled in the art and are not described here in detail, nor should they be construed as limitations of this application.

[0044] In summary, the embodiment of the present application provides a display panel 10 in which the lens array layer 220 is provided to more concentrate the light reflected by the fingerprint, resulting in a better recognition effect. The light shielding layer 230 can reduce interfering light (such as fingerprint reflected light at a large angle or ambient light) entering the fingerprint recognition module 110, thereby improving fingerprint recognition sensitivity. The light-transmitting holes 231 provided in the light shielding layer 230 can prevent stray light outside the display panel 10 from entering the fingerprint recognition module 110 and affecting the fingerprint recognition effect. Furthermore, the photosensitive module 200 and the fingerprint recognition module 110 are provided in the spacer area between the pixel areas of the display panel 10, thereby not affecting normal display. This allows for simultaneous support of multi-finger recognition over a large display area, resulting in higher fingerprint unlocking security and better fingerprint recognition results.

[0045] Furthermore, by setting up one fingerprint recognition module 110 corresponding to multiple light-transmitting holes 231, the size of the fingerprint recognition module 110 can be ensured to be larger, thereby reducing the requirements for the lens array layer 220 and its alignment accuracy, which is conducive to large-scale mass production; and under the premise that the fingerprint recognition resolution meets the requirements, the size of a single fingerprint recognition module 110 and the pixel size of the display panel 10 are quite different, which is conducive to reducing the interference of moiré patterns caused by the periodicity of the pixel display of the display panel 10 and the recognition method of the fingerprint recognition module 110, thereby improving the fingerprint recognition accuracy.

[0046] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0047] The above is a detailed introduction to a method for preparing a display panel 10 and a photosensitive module 200 thereof provided in an embodiment of the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea. At the same time, for those skilled in the art, based on the ideas of the present application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A display panel, characterized in that: include: A base substrate, wherein a fingerprint recognition module is provided in the base substrate; A photosensitive module is provided on the light-emitting side of the base substrate, comprising: a base layer, a lens array layer, and a light-shielding layer, wherein the lens array layer and the light-shielding layer are respectively provided on both sides of the base layer, and the light-shielding layer is provided close to the base substrate; in The light shielding layer is provided with light-transmitting holes corresponding to the lens array layer one by one, and the fingerprint recognition module collects and recognizes the fingerprint image located on the light-emitting side of the base substrate through the light-transmitting holes; The photosensitive module and the fingerprint recognition module are arranged in a spacing area between pixel areas of the display panel, and the fingerprint recognition module is arranged on one side of the light emitting surface of the display panel.

2. The display panel according to claim 1, wherein The fingerprint recognition module array is arranged in the base substrate, and one fingerprint recognition module is arranged corresponding to at least one light-transmitting hole.

3. The display panel according to claim 1, wherein The lens array layer includes a plurality of lenses, and the focal length of each lens is greater than the thickness of the base layer and less than the sum of the thicknesses of the base layer and the light shielding layer.

4. The display panel according to claim 3, wherein: The focused spot size of a single lens is slightly smaller than the size of the light-transmitting hole; The focused spot size of a single lens is in the range of 2 μm to 15 μm.

5. The display panel according to claim 1, wherein The photosensitive module further includes a protective layer, which is arranged on a side of the lens array layer away from the base layer and covers the lens array layer.

6. The display panel according to claim 1, wherein: The lens array layer is arranged in a quadrilateral or hexagonal manner.

7. The display panel according to claim 1, wherein: The light shielding layer includes a black positive photoresist, and the black positive photoresist contains a black light absorbing material.

8. The display panel according to claim 1, wherein: The invention also includes an optical adhesive layer, which is arranged between the base substrate and the photosensitive module and covers the light-transmitting hole.

9. A method for preparing a photosensitive module, wherein the photosensitive module is provided on the display panel according to claim 1, wherein: The steps include: providing a base layer; A lens array layer is prepared on one side of the substrate layer; Applying black positive photoresist on the other side of the base layer to form a light-shielding layer; The light shielding layer is exposed by using a micro-focusing method on a side of the lens array layer away from the light shielding layer, and the black positive photoresist in the exposed area is removed by development to form a light-transmitting hole.

10. The method for preparing a photosensitive module according to claim 9, wherein: The following steps are also included: After the lens array layer is prepared, a protective layer is deposited on the lens array layer; After the light-transmitting hole is formed, the protective layer is removed.

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