Patent Description:
Fingerprint recognition technology is widely used in fields of security and smart attendance, such as fingerprint punch-in, etc., and with the maturity and convenience of the technology, the fingerprint recognition technology is gradually used in smart phone terminals, and becomes a basic configuration of smart phones. With the development of full screen technology, optical fingerprint recognition solutions have been developing rapidly. How to design and manufacture a more optimized display device structure is a focus issue in the related art.

<CIT> discloses a display panel comprising a substrate, a plurality of pixel units, a first color film, and an optical sensing layer.

<CIT> discloses an integrated sensing module comprising an image sensing chip including photo sensing units arranged in a two-dimensional array, a micro-hole layer disposed on the image sensing chip and having one or multiple micro holes corresponding to the photo sensing units.

<CIT> discloses a display panel and an electronic device.

<CIT> discloses an optical imaging system with a variable light field for a biometrics application.

It is an object of the present invention to provide a display device and a manufacturing method thereof.

The object is achieved by the features of the respective independent claims. Further embodiments are defined in the corresponding dependent claims.

In order to clearly illustrate the technical solution of the embodiments of the present disclosure, the drawings of the embodiments will be briefly described in the following; it is obvious that the following described drawings are only related to some embodiments of the present disclosure, and thus are not limitative of the present disclosure.

In order to make objects, technical solutions and advantages of the embodiments of the present disclosure apparent, the technical solutions of the embodiments of the present disclosure will be described in a clearly and fully understandable way in connection with the accompanying drawings related to the embodiments of the present disclosure.

Unless otherwise defined, all the technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art to which the present disclosure belongs. The terms "first," "second," etc., which are used in the present disclosure, are not intended to indicate any sequence, amount or importance, but distinguish various components. Further, the terms such as "a," "an," "the," etc., are not intended to limit the amount, but indicate the existence of at least one. The terms "comprise," "comprising," "include," "including," etc., are intended to specify that the elements or the objects stated before these terms encompass the elements or the objects and equivalents thereof listed after these terms, but do not preclude the other elements or objects. The phrases "connect", "connected", etc., are not intended to define a physical connection or mechanical connection, but may include an electrical connection, directly or indirectly. "On," "under," "right," "left" and the like are only used to indicate relative position relationship, and when the position of the object which is described is changed, the relative position relationship may be changed accordingly.

A display device with an optical fingerprint recognition solution includes a filtering function layer, a prism film, and a photosensitive imaging device which are sequentially stacked and attached to a back side of a display panel, light-emitting units of the display device are configured to emit light upward, and the light emitted by the light-emitting units is reflected back by a finger and is collected and imaged in the photosensitive imaging device after filtering out interference light by the filtering function layer. Because the reflectivity of the light on ridges of the finger is different from that of the light on valleys of the finger, fingerprint recognition can be realized, and an image comparison and algorithm processing, etc., may be performed in a processing chip integrated in the photosensitive imaging device or an external processing chip.

In the above display device, the filtering function layer, the prism film, and the photosensitive imaging device are required to be sequentially attached on the back side of the display panel, and there are many attaching processes between components. Moreover, in the case where the filtering function layer is attached on the prism film, due to insufficient sealing at edges, problems, such as light leakage and warpage, etc., of the filtering function layer may occur, which may make the fingerprint recognition invalid, make the assembly yield of each component not high, and make a reducible space of an overall thickness of a fingerprint recognition module (including the filtering function layer, the prism film, and the photosensitive imaging device) extremely limited.

At least one embodiment of the present disclosure provides a display device, and the display device includes a display panel and a photosensitive imaging device. The display panel includes a display side and a back side opposite to the display side, and the display panel further includes a filter layer disposed at the back side of the display panel. The photosensitive imaging device is stacked with the display panel and located at a side of the filter layer facing away from the display side, and the photosensitive imaging device is configured to detect a skin texture image of a user touching the display panel.

At least one embodiment of the present disclosure provides the display device and a manufacturing method of the display device, the display panel in the display device includes the filter layer having the filtering function, and the photosensitive imaging device is stacked with the display panel and located at the side of the filter layer facing away from the display side, which reduces attaching processes between components and improves the assembly yield of each component, and attaching the filtering function layer on the prism becomes unnecessary, thereby avoiding the problems, such as light leakage and warpage, etc., of the filtering function layer, which improves the accuracy of the fingerprint recognition, and because the filter layer has a filtering function, additionally attaching the filtering function layer on the fingerprint recognition module becomes unnecessary, thereby reducing the overall thickness of the fingerprint recognition module.

Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. It should be noted that same or similar reference numerals in different drawings will be used to refer to the same elements that have been described.

<FIG> is a schematic cross-sectional diagram of a display device <NUM> according to some embodiments not forming part of the present invention but useful to understand it; <FIG> is a schematic plan diagram of a display panel <NUM> according to the embodiments; <FIG> is a schematic cross-sectional diagram of another display device <NUM> according to the embodiments; and <FIG> is a schematic cross-sectional diagram of still another display device <NUM> according to the embodiments.

Referring to <FIG>, the display device <NUM> includes a display panel <NUM> and a photosensitive imaging device <NUM>. The display panel <NUM> includes a display side <NUM> and a back side <NUM> opposite to the display side, and further includes a filter layer <NUM> disposed at the back side <NUM> of the display panel. The photosensitive imaging device <NUM> is stacked with the display panel <NUM> and located at a side of the filter layer <NUM> facing away from the display side <NUM>. In addition, the display panel <NUM> and the photosensitive imaging device <NUM> are sequentially stacked, and the photosensitive imaging device <NUM> is located in a display area <NUM> of the display panel <NUM> and located on the back side of the display panel <NUM>. Therefore, the display device integrates a display function and an under-screen skin texture recognition function. For example, the filter layer functions as a bottom layer film (for example, a base substrate) of the display panel <NUM>, that is, the display panel <NUM> has a bottom layer film with a filtering function, which filters out the interference light from the light incident on the display side during operations, so that the light reflected by the skin texture is collected and imaged on the photosensitive imaging device, thereby improving imaging quality and improving fingerprint recognition effect.

The display panel <NUM> may be an organic light-emitting diode (OLED) display panel, or may be an electronic paper display panel, which is not limited in the embodiments of the present disclosure. The OLED display panel may be, for example, a flexible OLED display panel. The OLED display panel has self-luminous characteristics, and the light emitted by the display pixel units of the OLED display panel can further be controlled or modulated as desired, thereby providing convenience for fingerprint image collection, and contributing to improve the integration level of the electronic device.

As shown in <FIG>, the display panel <NUM> includes the display side <NUM> having a display area <NUM> and the back side <NUM> opposite to the display side. The display area <NUM> includes a fingerprint recognition area <NUM>. The fingerprint recognition area <NUM> may be part or all of the display area <NUM>, thereby realizing a partial under-screen fingerprint recognition function or a full under-screen fingerprint recognition function. The user can put his/her finger in the fingerprint recognition area <NUM> or press upon the fingerprint recognition area <NUM>. When a light-emitting unit of the display device emits light, the light emitted by the light-emitting unit is reflected back by the finger, and is collected and imaged on the photosensitive imaging device <NUM>. Then a fingerprint image obtained by the photosensitive imaging device <NUM> can be subsequently used for a fingerprint recognition operation.

The photosensitive imaging device <NUM> may be configured to collect skin texture images of a user, such as fingerprint images and palm print images, etc., and thus the skin texture images of the user may be used for realizing functions such as fingerprint recognition and palm print recognition, etc. The photosensitive imaging device <NUM> has a certain working area (an active area), and includes a plurality of pixel units that are arranged in a predetermined array. The photosensitive imaging device <NUM> is coupled to a processor (for example, an integrated circuit chip) by, for example, a lead(s), so that the collected fingerprint image may be transmitted to the processor in a data signal manner. The photosensitive imaging device <NUM> may be various suitable types of fingerprint sensors, such as a charge coupled device (CCD) type image sensor, a complementary metal oxide semiconductor (CMOS) type image sensor, etc. According to requirements, the photosensitive imaging device <NUM> may, for example, sense only light of a certain wavelength (for example, red light or green light), or may sense all visible light. The following specific example will be described by taking that the photosensitive imaging device <NUM> is configured as a fingerprint sensor for fingerprint recognition as an example.

As shown in <FIG>, the filter layer <NUM> having the filtering function is disposed between the photosensitive imaging device <NUM> and the back side of the display panel <NUM>, and is configured to support the pixel unit array of the display panel <NUM>. The pixel unit array may be directly manufactured on the filter layer <NUM>. In this structure, when the display panel emits light, for example, the light-emitting device of the display panel <NUM> itself can be made to emit light, or an external light source (such as a backlight) can further be provided to enable the display panel <NUM> to emit light, after the finger reflects back the light emitted by the light panel <NUM>, the interference light (such as infrared light) is filtered out by the filter layer <NUM> having the filtering function, so that the reflected light, which has been subjected to filtering, reaches the photosensitive imaging device <NUM>, and is collected and imaged on the photosensitive imaging device <NUM>. Then the fingerprint image obtained by the photosensitive imaging device <NUM> may be used for subsequent fingerprint recognition operations.

In this example, for example, the filter layer <NUM> having the filtering function is provided as the back side of the display panel <NUM>, and the photosensitive imaging device <NUM> is attached to the back side (that is, a side opposite to the pixel unit array) of the filter layer <NUM> having the filtering function with a double-sided tape or an adhesive, so that the filter layer <NUM> and the photosensitive imaging device <NUM> are stacked on the back side of the display panel <NUM>. Of course, the filter layer <NUM> and the photosensitive imaging device <NUM> may be fixed to each other in other ways.

In the above structure, the filter layer <NUM> having the filtering function is of a single body which is manufactured with the filtering function in advance, for example, the filter layer, which is of a single body, is formed by depositing the filtering function layer on a substrate mother layer in advance (the manufacturing process of the filter layer will be described in detail later). Because the filter layer has the filtering function as a whole, the process of attaching the filtering function layer on the prism can be omitted, and the thickness of the fingerprint recognition module and the thickness of the entire display device can be reduced.

In another example, as shown in <FIG>, the filter layer <NUM> having the filtering function may not be of a single body, which is manufactured with the filtering function in advance, but may include a substrate layer <NUM> and a filtering function layer <NUM> having the filtering function, which are stacked and attached with each other. In this example, the substrate layer <NUM> supports the pixel unit array of the display panel <NUM>, the filtering function layer <NUM> may be attached to the substrate layer <NUM> by a double-sided tape or an adhesive, and the photosensitive imaging device <NUM> may be attached to the back side of the filtering function layer <NUM> by a double-sided tape or an adhesive, so that the substrate layer <NUM>, the filtering function layer <NUM> and the photosensitive imaging device <NUM> are stacked on the back side of the display panel <NUM>. Similarly, the substrate layer <NUM>, the filtering function layer <NUM> having the filtering function, and the photosensitive imaging device <NUM> may be fixed to each other in other ways.

Please refer to <FIG>, in the direction perpendicular to the display panel <NUM>, the filtering function layer <NUM> partially or completely covers the bottom of the substrate layer <NUM>, and the projection of the photosensitive imaging device <NUM> on the substrate layer <NUM> is located within the projection of the filtering function layer <NUM> on the substrate layer <NUM>. For example, the size of the projection of the filtering function layer <NUM> on the substrate layer <NUM> may be equal to the size of the substrate layer <NUM>, for example, the filtering function layer <NUM> and the substrate layer <NUM> are obtained by the same cutting process as described below, and the size of the projection of the photosensitive imaging device <NUM> on the substrate layer <NUM> is smaller than the size of the substrate layer <NUM>.

By attaching the filtering function layer on the substrate layer, and locating the projection of the photosensitive imaging device on the substrate layer within the projection of the filtering function layer on the substrate layer, problems of the filtering function layer, such as light leakage and warpage, etc., which are cause by the insufficient sealing at edges, in the case where the filtering function layer is attached on the prism, may be avoided. In the case where the problem of light leakage of the filtering function layer is alleviated, more stray light may be effectively filtered out, thereby further improving the accuracy of the fingerprint recognition.

Because infrared light has a strong penetrating ability and cannot form reflections at ridges and valleys of a finger, infrared light belongs to stray light and can reduce a signal-to-noise ratio and affect imaging quality. Therefore, in this example, the filtering function layer <NUM> may be an infrared light filtering function layer for filtering infrared stray light. Of course, the filtering function layer <NUM> may be implement in more than one way. For example, the filtering function layer <NUM> may include one or more of an infrared light filtering function layer, an ultraviolet light filtering function layer, a visible light filtering function layer, and a far infrared light filtering function layer. In different application scenarios, by setting the filtering function layer to filter out different types of stray light, the application scenarios of the embodiments of the present disclosure are more extensive.

In another example, as shown in <FIG>, the photosensitive imaging device <NUM> may include a prism film <NUM>, and the prism film <NUM> is disposed at a light incident side <NUM> of the photosensitive imaging device <NUM>. In this example, the photosensitive imaging device <NUM> is combined with the filter layer <NUM> by the prism film <NUM>, for example, the filter layer <NUM> and the prism film <NUM> are combined by adhering to each other, so that the photosensitive imaging device <NUM> is stacked with the display panel <NUM> and located at the side of the filter layer <NUM> facing away from the display side <NUM>.

In this exemplary structure, when the display panel emits light, for example, the light-emitting device of the display panel <NUM> itself can be made to emit light, or an external light source (such as a backlight) can further be provided to enable the display panel <NUM> to emit light, after the finger reflects back the light emitted by the light panel <NUM>, the interference light is filtered out by the filter layer <NUM> having the filtering function, so that the reflected light, which has been subjected to the filtering, reaches the prism film <NUM>, the prism film <NUM> brightens the filtered reflected light, and then the light that has been brightened is transmitted to the photosensitive imaging device <NUM> (for example, a sensor) for imaging. Then the fingerprint image obtained by the photosensitive imaging device <NUM> can be used for a subsequent fingerprint recognition operation.

In this example, the photosensitive imaging device <NUM> may be attached to a back side of the prism film <NUM> by a double-sided tape, and the prism film <NUM> may be attached to the back side of the filter layer <NUM> by a double-sided tape, so that the photosensitive imaging device <NUM>, the prism film <NUM>, and the filter layer <NUM> are stacked on the back side of the display panel <NUM>. Similarly, the filter layer <NUM>, the prism film <NUM>, and the photosensitive imaging device <NUM> may be fixed to each other by other ways.

In some embodiments, the display device <NUM> further includes a back plate <NUM> which is configured to provide support and protection for the display device <NUM>. For example, the stacked structure of the filter layer <NUM> and the photosensitive imaging device <NUM> may further directly or indirectly abut on the back plate <NUM>, and may be relatively fixed on the back plate <NUM>.

Of course, the structure of the display device <NUM> according to any of the embodiments of the present disclosure is not limited to the exemplary structures as shown in <FIG>. For example, the display device <NUM> may further include other devices, such as a driving chip, a memory, a microphone, a speaker, etc., which will not be described in detail here.

At least one embodiment of the present disclosure provides a display device, a display panel of the display device includes a filter layer having a filtering function, and a photosensitive imaging device is stacked with the display panel and located at a side of the filter layer facing away from the display side, which reduces attaching processes between components and therefore improves the assembly yield of each component. Moreover, in these embodiments, attaching the filtering function layer on the prism of the photosensitive imaging device becomes unnecessary, thereby avoiding problems, such as light leakage and warpage, etc., of the filtering function layer, and thereby improving the accuracy of the fingerprint recognition. In addition, because the filter layer has a filtering function, additionally attaching the filtering function layer on the fingerprint recognition module is not necessary, thereby reducing the overall thickness of the fingerprint recognition module. For example, the filter layer functions as a bottom layer film of the display panel, and is disposed at the back side of the display panel.

<FIG> is a schematic cross-sectional diagram of another display device <NUM> according to some embodiments of the present disclosure. Referring to the embodiment of <FIG>, the display device <NUM> includes a display panel <NUM> and a photosensitive imaging device <NUM>. In the present embodiment, the display panel <NUM> is an OLED display panel.

As shown in <FIG>, the OLED display panel <NUM> includes a top film <NUM>, a thin film package <NUM>, a pixel unit array <NUM>, a flexible substrate <NUM>, a filtering function layer <NUM>, and a bottom layer film <NUM>, etc. In the display panel, the stack of the filtering function layer <NUM> and the bottom layer film <NUM>, as a whole, provides a filter layer having a filtering function, and functions as a bottom layer film of the display panel, which is located on a back side of the display panel, specifically, which is a side opposite to the pixel unit array <NUM> on the flexible substrate <NUM>.

The bottom layer film <NUM> provides a protection and support function for other structures and functional layers thereon, and the bottom layer film <NUM> may be, for example, a stronger plastic substrate or a plastic substrate or a glass substrate with a higher strength. The filtering function layer <NUM> is located on the bottom layer film <NUM> for filtering out the stray light. The filtering function layer <NUM> may include one or more of an infrared light filtering function layer, an ultraviolet light filtering function layer, a visible light filtering function layer, and a far infrared light filtering function layer. The flexible substrate <NUM> is configured to provide a buffer, such as a flexible substrate made of a material such as polyimide (PI), polypropylene (PP), polycarbonate (PC), etc..

The pixel unit array <NUM> is formed on the flexible substrate <NUM>, and includes a plurality of pixel units arranged in a predetermined array and signal lines (including gate lines, data lines, detection lines, etc.) for providing electrical signals (including scanning signals, data signals, detection signals, etc.). Each pixel unit includes a light-emitting device (for example, an OLED device) and a pixel driving circuit for driving the light-emitting device (the OLED device) to emit light, etc. The pixel driving circuit is coupled to the signal line, so that the pixel driving circuit can receive a corresponding control signal and a driving voltage, and drive the light-emitting device to emit light as requirements, thereby performing functions such as display, touching sensing, or skin texture (such as fingerprint) recognition, etc. Light <NUM> emitted by the pixel units may be used for displaying, and also used as incident light for the under-screen fingerprint detection. Specifically, the light <NUM> emitted by the light-emitting devices in the pixel units, when the light-emitting device is working, is reflected by a user's skin (a finger or a palm) <NUM> on the display side of the display panel for the skin texture image recognition of the user.

The thin film package <NUM> covers the pixel unit array <NUM> to prevent outside water vapor from entering the pixel unit array <NUM> to cause aging or deterioration. The thin film package <NUM> may be a multilayer thin film package, for example, including a stacked inorganic insulating layer and an organic insulating layer, etc..

The top film <NUM> may be a cover plate, such as a substrate or a thick film made of glass or plastic, and is configure to provide support and protection, for example, for the user to perform operations such as touching, pressing, etc..

According to requirements, the OLED display panel <NUM> may further include other structures or functional layers. For example, the OLED display panel <NUM> may include a touch structure for realizing a touch function. The touch structure may be built in the pixel unit array <NUM>, or formed on the top film, and the touch structure may be in, for example, a capacitive type, a resistive type, etc..

In order to realize the under-screen fingerprint detection function, the top film <NUM>, the thin film package <NUM>, the flexible substrate <NUM>, the filtering function layer <NUM>, and the bottom layer film <NUM>, which are described above, are at least partially transparent. The light <NUM> (indicated by a solid arrow) emitted by the light-emitting device in the pixel unit, in a case where the light-emitting device is working, is reflected by the skin (a finger or a palm) <NUM> of the user on the display side of the display panel, and the reflected light (indicated by a dashed arrow) may be incident on the photosensitive imaging device <NUM>, so that the photosensitive imaging device <NUM> may form an image, and the image, which is obtained, is used to implement subsequent fingerprint recognition operations. The photographic imaging device <NUM> may include a prism film <NUM>, and the prism film <NUM> is disposed at a light incident side of the photosensitive imaging device <NUM>. The photosensitive imaging device <NUM> is combined with the bottom layer film <NUM> by the prism film <NUM>, so that the photosensitive imaging device <NUM> is stacked with the display panel <NUM>, and disposed at a side of the bottom layer film <NUM> of the display panel facing the photosensitive imaging device <NUM>. The light reflected by the skin (the finger or the palm) <NUM> of the user on the display side of the display panel is incident on the photosensitive imaging device <NUM> by the prism film <NUM>.

In at least one embodiment of the present disclosure, in order to use the principle of pinhole imaging to improve the effect of the photosensitive imaging device <NUM>, a pinhole(s) may further be formed in the layer structure as shown in <FIG> (for example, a pinhole layer including a pinhole(s) is provided separately), and the pinhole(s) corresponds to the photosensitive imaging device <NUM>.

The display device according to at least one embodiment of the present disclosure reduces attaching processes between components and improves the assembly yield of each component.

<FIG> is a block diagram of still another display device <NUM> according to some embodiments of the present disclosure, the display device is, for example, a mobile phone or a tablet computer. As shown in <FIG>, the display device <NUM> includes a display panel <NUM>, a touch structure <NUM>, a photosensitive imaging device <NUM>, a controller <NUM> and a fingerprint processor <NUM>. The ways to implement display panel <NUM> and the photosensitive imaging device <NUM> are the same as those of the display panel <NUM> and the photosensitive imaging device <NUM> in the above embodiments, and details are not described herein again. The touch structure <NUM> is coupled to the display panel <NUM>, the photosensitive imaging device <NUM>, and the controller <NUM>, respectively. The controller <NUM> is coupled to the display panel <NUM>, the touch structure <NUM>, the photosensitive imaging device <NUM>, and the fingerprint processor <NUM>, respectively.

In some embodiments, when the touch structure <NUM> senses a user's pressing action on a display side of the display panel <NUM>, the touch structure <NUM> transmits a feedback signal to the controller <NUM>. The feedback signal may include information that the display panel <NUM> is pressed by a user, and may further include information such as a pressing degree (level), a pressing position, etc..

The controller <NUM> receives the feedback signal transmitted by the touch structure <NUM>. The controller <NUM> controls the display panel <NUM> to emit light, that is, to light up the screen. Under this case, the controller <NUM> further controls the photosensitive imaging device <NUM> to start to collect a fingerprint image(s) and transmit the fingerprint image(s) to the fingerprint processor <NUM> for fingerprint recognition (and verification) of the user. After that, the fingerprint processor <NUM> transmits a recognition result to the controller <NUM>, and the controller <NUM> performs subsequent (predetermined) operations according to the fingerprint recognition result. In a case where the controller <NUM> controls the display panel <NUM> to emit light to light up the screen, for example, a system of a mobile phone or a tablet is in a standby state, it is waited for a user to enter a password, etc., to unlock the system. Accordingly, in the case where the fingerprint recognition is successful, the controller <NUM> controls the system of the mobile phone or the tablet to enter into a working state, for example, an operation interface of an application before being in an off-screen state is displayed. The embodiments of the present disclosure are not limited thereto.

As a modified embodiment, the photosensitive imaging device <NUM> may transmit the fingerprint image imaged thereon to the controller <NUM>, and the controller <NUM> transmits the user fingerprint image to the fingerprint processor <NUM>, so that the fingerprint processor <NUM> completes the texture image recognition of the user. For example, if the texture recognition of the user is successful, the controller <NUM> releases a system lock state of an electronic device including the display device. If the texture recognition of the user or verification fails, the controller <NUM> controls the display panel <NUM> not to emit light, i.e., makes the display device <NUM> remain in the off-screen state.

In some embodiments of the present disclosure, the fingerprint processor may be implemented by a general-purpose processor or a special-purpose processor. The controller may be various types of integrated circuit chips with processing functions, which may have various computing architectures, such as a complex Instruction Set Computer (CISC) structure, a Reduced Instruction Set Computer (RISC) structure, or a structure that implements a combination of multiple instruction sets. In some embodiments, the controller may be a microprocessor, such as an X86 processor or an ARM processor, or may be a digital processor (DSP), etc..

Other embodiments of the present disclosure provide a manufacturing method of the display device described above, and the manufacturing method and a working principle of the display device according to at least one embodiment of the present disclosure will be exemplarily described below with reference to <FIG>.

At step S401, a display panel is provided, the display panel includes a display side and a back side opposite to the display side, and the display panel further includes a filter layer disposed at the back side of the display panel.

The display panel may be any display panel in the above embodiments, and details are not described herein again.

At step S402, a photosensitive imaging device is provided, the photosensitive imaging device are sequentially stacked with the display panel and located at a side of the filter layer facing away from the display side, and the photosensitive imaging device is configured to detect a skin texture image of the user touching the display panel.

The filter layer having the filtering function may be a filter layer as a single body, which is manufactured in advance, for example, it may be used as a bottom layer film of the display panel, that is, the filter layer as a whole has the filtering function, or may include a substrate layer and a filtering function layer having a filtering function, which are stacked and attached to each other. Further, for example, the filtering function layer may include one or more of an infrared light filtering function layer, an ultraviolet light filtering function layer, a visible light filtering function layer, and a far infrared light filtering function layer.

The photosensitive imaging device may include a prism film, and the method further includes step S403. The prism film is disposed at a light incident side of the photosensitive imaging device. The photosensitive imaging device may be combined with the filter layer by the prism film, so that the photosensitive imaging device is stacked with the display panel and located at the side of the filter layer facing away from the display side.

For the specific implementation process of the above steps may further refer to the description of the above embodiments of the display device, and details are not described herein again.

A manufacturing method of a display device according to at least one embodiment of the present disclosure may reduce attaching processes between components and improve the assembly yield of each component. And attaching a filtering function layer on the prism becomes unnecessary, thereby avoiding problems, such as light leakage and warpage, etc., of the filtering function layer, and thereby improving the accuracy of the fingerprint recognition. And because the filter layer has a filtering function, additionally attaching the filtering function layer on the fingerprint recognition module is not necessary, thereby reducing the overall thickness of the fingerprint recognition module.

Other embodiments of the present disclosure further provide a filter layer for forming a display device. The filter layer may be used in the display device in the above embodiments, and the filter layer has a filtering function.

The filter layer having the filtering function may be the filter layer having the filtering function as a whole, which is manufactured in advance, that is, the filter layer as a whole has the filtering function, or may include a substrate layer and the filtering function layer having the filtering function, which are stacked and attached with each other. Further, for example, the filtering function layer may include one or more of an infrared light filtering function layer, an ultraviolet light filtering function layer, a visible light filtering function layer, and a far infrared light filtering function layer.

The filter layer for forming the display device according to at least one embodiment of the present disclosure, in the case where the filter layer is used in the display device, attaching processes between components is reduced and the assembly yield of each component is improved. And attaching a filtering function layer on the prism is not necessary any more, thereby avoiding problems, such as light leakage and warpage, etc., of the filtering function layer, and thereby improving the accuracy of the fingerprint recognition. Because the filter layer has a filtering function, additionally attaching the filtering function layer on the fingerprint recognition module is not necessary, thereby reducing the overall thickness of the fingerprint recognition module.

Another embodiment of the present disclosure provides a manufacturing method of the filter layer having the filtering function, which is mentioned above, and the manufacturing method of the filter layer may be used for manufacturing the filter layer used in the display device, and the method includes: forming a filtering function layer on a first side of a substrate mother layer to obtain the filter layer having the filtering function.

Hereinafter, the manufacturing method and the working principle of the filter layer having the filtering function according to at least one embodiment of the present disclosure will be exemplarily described below with reference to <FIG>.

At step S501, before forming a filtering function layer on the first side of the substrate mother layer, a first release film on the first side of the substrate mother layer is removed.

For example, the substrate mother layer may be a roll of PET (Polyethylene terephthalate), PMMA (poly (methyl methacrylate)), etc. In order to realize curling into the roll, a release film is usually attached to one or both sides of the substrate mother layer. In order to form the filtering function layer on the first side of the substrate mother layer, the first release film of the substrate mother layer is removed at first, which makes the filtering function layer be better attached to the substrate mother layer.

At step S502, before forming the filtering function layer on the first side of the substrate mother layer, an ion cleaning processing is performed on the first side of the substrate mother layer, from which the first release film is removed.

Performing the ion cleaning processing on the first side of the substrate mother layer may further remove organic objects (such as the previously used adhesive) attached to the surface of the first side, so that the filtering function layer may be better attached to the substrate mother layer.

At step S503, a filtering function layer is formed on the first side of the substrate mother layer to obtain the filter layer having the filtering function.

In the case where the light emitted from the display panel and reflected by user skin or light incident from outside may form stray light in a large viewing angle, which will affect a recognition result of the skin texture of the user by the photosensitive imaging device. Therefore, it is necessary to filter out the stray light by the filtering function layer.

There implementation methods of forming the filtering function layer on the first side of the substrate mother layer are many. For example, the filtering function layer may be formed by using a material having an adsorption effect on a certain type of light, or the filtering function layer may be formed by setting a film layer structure of the filtering function layer (for example, selecting refractive indexes of mediums on both sides of an interface on a light incident path to filter out stray light). The filtering function layer does include at least one film layer group, each film layer group includes a plurality of film layers, and the filtering function layer is formed by sequentially forming the plurality of film layers of the at least one film layer group.

<FIG> is a schematic diagram of a layer structure of a filtering function layer according to some embodiments not forming part of the present invention but useful to understand it. Referring to <FIG>, the filtering function layer includes a first reflection film layer group <NUM>, the first reflection film layer group <NUM> includes a film layer <NUM> having a first refractive index and a film layer <NUM> having a second refractive index disposed at intervals, and the first refractive index is greater than the second refractive index. Of course, it can be understood that the first reflection film layer group <NUM> is not limited to the structure as shown in <FIG>. For example, the first reflection film layer group <NUM> may include a plurality of (e.g., <NUM> to <NUM>) film layers <NUM> having the first refractive index and a plurality of (e.g., <NUM> to <NUM>) film layers <NUM> having the second refractive index.

In the present embodiment, filtering out the stray light may be implemented by controlling the film layers <NUM> having the first refractive index and the film layers <NUM> having the second refractive index in the first reflection film layer group <NUM>. For example, filtering out the stray light may be implemented by selecting various first refractive indexes and various second refractive indexes. The first refractive index may be set to be <NUM> to <NUM>, and the second refractive index may be set to be <NUM> to <NUM>. Of course, the setting of the magnitudes of the first refractive index and the second refractive index is not limited to the above embodiments. As another example, filtering out the stray light may be implemented by selecting different materials for the film layer. The material of the film layer having the first refractive index may include Ge or PbTe, and the material of the film layer having the second refractive index may include ZnS, ZnSe, TiO2 or SiO2. Similarly, the selection of the materials of the film layer having the first refractive index and the selection of the materials of the film layer having the second refractive index are not limited thereto. Still for another example, filtering out the stray light may be implemented by setting different thicknesses of the materials of the film layer. The thickness of the material of the film layer having the first refractive index may be set to be <NUM> to <NUM> nanometers, and the thickness of the material of the film layer having the second refractive index may be set to be <NUM> to <NUM> nanometers. Similarly, the selection of the thickness of the film layer having the first refractive index and the selection of the thickness of the film layer having the second refractive index are not limited thereto.

The refractive index may be increased by the different settings of the film layers having the first refractive index and the film layers having the second refractive index, which is described above. For example, by setting of the above parameters, high transmittance (more than <NUM>%) for visible light at <NUM> ~ <NUM> and low transmittance (less than <NUM>%) of infrared light at <NUM> ~ <NUM> may be achieved. In the case where the stray light is filtered out, effective light used for the photosensitive imaging device increases, thereby further improving the accuracy of the fingerprint recognition.

In this example, in the case where the incident angle of light <NUM> incident from the display side of the display panel is smaller than a total reflection angle θ1, the light <NUM>, which is incident, may pass through the interface between the film layer <NUM> having the first refractive index of the first reflection film layer group <NUM> and the film layer <NUM> having the second refractive index of the first reflection film layer group <NUM>, and further form an image on the photosensitive imaging device. In the case where the incident angle of light <NUM> incident on the display side of the display panel is greater than θ1, because an incident angle θ2 of the light <NUM> is greater than the total reflection angle θ1, the light <NUM> is totally reflected at the interface between the film layer <NUM> having the first refractive index of the first reflection film layer group <NUM> and the film layer <NUM> having the second refractive index of the first reflection film layer group <NUM>, and cannot reach the photosensitive imaging device to be imaged, thus realizing the filtering function of the filtering function layer by the principle of total reflection.

<FIG> is a schematic structure of a layer structure of a filtering function layer according to another embodiment of the present invention. Please refer to <FIG>, the filtering function layer includes a first reflection film layer group <NUM>, a spacer film layer group <NUM> and a second reflection film layer group <NUM>. The first reflection film layer group <NUM>, the spacer film layer group <NUM>, and the second reflection film layer group <NUM> are sequentially stacked on the first side of the substrate mother layer.

The first reflection film layer group <NUM> and the second reflection film layer group <NUM> include at least one film layer <NUM> having the first refractive index and at least one film layer <NUM> having the second refractive index. This setting is similar to the setting of the first reflection film layer group <NUM> in the previous embodiment, and details are not described herein again.

The spacer film layer <NUM> may include a plurality of film layers having a same refractive index, in the embodiment, the refractive index may be set to the first refractive index or the second refractive index. For example, as shown in <FIG>, a plurality of film layers <NUM> having the first refractive index may be included, or as shown in <FIG>, a plurality of film layers <NUM> having the second refractive index may be included. For related settings of the first refractive index and the second refractive index, reference may be made to the description of the corresponding embodiment of <FIG>, and details are not described herein again. In addition, a number of film layers included in the spacer film layer <NUM> may be set as requirements, and for example, may include <NUM> to <NUM> layers.

In this example, in the case where the light incident on the display side of the display panel first reaches the first reflection film layer group, the stray light may be filtered out by the principle of the total reflection. If part of the stray light is still not filtered out and remains in the first reflective film group, the part of the stray light will produce a light trapping effect due to a structure formed by the first reflection film layer group and the spacer film layer group and a structure formed by the spacer film layer group and the second reflection film layer group, so that the part of stray light cannot reach the photosensitive imaging device to be imaged. The filter film with a multi-film layer group structure realizes the filtering function by the principle of the total reflection and the light trapping effect.

The filtering function layer, which is composed of multi-film layer group further enhances the filtering function. In the case where more stray light is filtered out, effective light reaching the photosensitive imaging device will increase, thereby further improving the accuracy of the fingerprint recognition.

Further referring to <FIG>, the method further includes step S504, attaching a second release film on the first side of the substrate mother layer on which the filtering function layer is formed to obtain the filter layer with the filtering function.

Therefore, after forming the filtering function layer, a release film may be attached to the first side surface of the substrate mother layer, and then the filter layer with the filtering function, which is obtained, may be curled into the roll, for storage and transportation, etc. The second release film is attached on the first side after forming the filtering function layer, which may prevent water, oxygen, and charged ions, and prolong service life of the filtering function layer.

After the filter layer having the filtering function is manufactured, the filter layer may be provided to a manufacturing factory of a display device. During a manufacturing process of the display panel, after removing the second release film on the surface of the filtering function layer of the filter layer having the filtering function, the second release film is cut to an appropriate size for forming a back side of the display panel and using as a bottom layer film of the display panel, which is configured to provide support and protection for the display panel. For example, after a pixel unit array is manufactured on a flexible substrate, the pixel unit array is peeled off as a whole, transferred onto the bottom layer film, and combined with the bottom layer film.

The manufacturing method of a filter layer of forming a display device according to at least one embodiment of the present disclosure, in the case where the manufacture method is used to manufacture a display device, reduces attaching processes between components and improves the assembly yield of each component. And attaching a filtering function layer on the prism is not necessary, thereby avoiding problems, such as light leakage and warpage, etc., of the filtering function layer, and thereby improving the accuracy of the fingerprint recognition. And because the filter layer has a filtering function, additionally attaching the filtering function layer on the fingerprint recognition module is not necessary any more, thereby reducing the overall thickness of the fingerprint recognition module.

The following statements should be noted:.

Claim 1:
A display device (<NUM>) comprising:
a display panel (<NUM>) and a photosensitive imaging device (<NUM>), wherein
the display panel (<NUM>) comprises a display side (<NUM>) and a back side (<NUM>) opposite to the display side (<NUM>), and the display panel (<NUM>) further comprises a filter layer (<NUM>) disposed at the back side (<NUM>) of the display panel (<NUM>),
the photosensitive imaging device (<NUM>) is stacked with the display panel (<NUM>) and located at a side of the filter layer (<NUM>) facing away from the display side (<NUM>), and the photosensitive imaging device (<NUM>) is configured to detect a skin texture image of a user touching the display panel (<NUM>), and
the display panel (<NUM>) further comprises a pixel unit, the pixel unit comprises a light-emitting device, and the display panel (<NUM>) is configured to allow light emitted by the light-emitting device, in a case where the light-emitting device is working, to be reflected by a user skin touching the display panel (<NUM>), for skin texture image recognition,
wherein
the filter layer (<NUM>) comprises a substrate layer (<NUM>) and a filtering function layer (<NUM>) having a filtering function, and the substrate layer (<NUM>) and the filtering function layer (<NUM>) are stacked and combined with each other,
the filtering function layer (<NUM>) comprises at least one film layer group, each film layer group comprises a plurality of film layers, wherein the filtering function layer (<NUM>) comprises a first reflection film layer group (<NUM>), and the first reflection film layer group (<NUM>) comprises at least one film layer (<NUM>) having a first refractive index and at least one film layer (<NUM>) having a second refractive index, which are disposed at intervals, and the first refractive index is greater than the second refractive index,
characterized in that
the filtering function layer (<NUM>) further comprises a spacer film layer group (<NUM>) and a second reflection film layer group (<NUM>), the first reflection film layer group (<NUM>), the spacer film layer group (<NUM>), and the second reflection film layer group (<NUM>) are sequentially stacked on the first side of the substrate layer, and
the second reflection film layer group (<NUM>) comprises at least one film layer (<NUM>) having the first refractive index and at least one film layer (<NUM>) having the second refractive index, and the spacer film layer comprises a plurality of film layers with a same refractive index.