TWI780436B - Under-screen fingerprint identification device - Google Patents

Abstract

An under-screen fingerprint identification device adapted to sense a finger is provided. The under-screen fingerprint identification device includes an image sensing element and a display module. The display module is disposed on the image sensing element. The display module includes a light source module, a diffusion layer and a transparent protective layer. The diffusion layer is disposed in the light source module. The diffusion layer has a first area and a second area. The transparent protective layer is disposed on the diffusion layer and has a finger pressing area. In the direction perpendicular to the extension direction of the display module, the position of the finger pressing area is overlapped with the image sensing element and the first area of the diffusion layer. The image sensing element is adapted to receive a reflected beam reflected by the finger and transmitted through the first area, and the transmittance of the first region to the reflected beam is greater than the transmittance of the second region to the reflected beam.

Description

Under-screen fingerprint recognition device

The present invention relates to an electronic device, and in particular to an under-display fingerprint identification device.

In order to increase the screen-to-body ratio of displays, under-display fingerprint sensing technology has become a trend. To put it simply, the under-display fingerprint sensing technology is to dispose the fingerprint sensor under the display screen of the electronic device. After the electronic device detects that the user touches the display screen, the electronic device controls the display screen to emit light to illuminate the surface of the user's finger. The light can be reflected by the user's finger into the fingerprint sensor under the display screen, and the reflected light is converted into a digital image signal by the fingerprint sensor to obtain the fingerprint image of the user. However, in the current development, the liquid crystal display has a large number of structural layers, and the internal brightness enhancement film layer and diffusion layer will reduce the image quality, so that the fingerprint imaging device below cannot obtain the image.

The invention provides an under-display fingerprint identification device, which allows a user to directly sense an under-display fingerprint by pressing a display area of a display module, and at the same time allows the display module to have a good display effect.

The present invention provides an under-screen fingerprint identification device, which is suitable for sensing fingers. The under-screen fingerprint identification device includes an image sensing element and a display module. The display module is configured on the image sensing element. The display module includes a light source module, a diffusion layer and a light-transmitting protective layer. The diffusion layer is configured on the light source module. The diffusion layer has a first region and a second region. The light-transmitting protection layer is arranged on the diffusion layer and has a finger pressing area, wherein the position of the finger pressing area overlaps with the image sensing element and the first area of the diffusion layer in a direction perpendicular to the extending direction of the display module. The finger pressing area does not overlap the second area, the image sensing element is suitable for receiving the reflected beam reflected by the finger and passed through the first area, and the transmittance of the first area to the reflected beam is greater than the transmittance of the second area to the reflected beam .

In an embodiment of the present invention, a first gain layer is disposed on the surface of the above-mentioned first region. The refractive index of the first gain layer matches the refractive index of the first region, and the reflected light beam reflected by the finger passes through the first gain layer to be transmitted to the image sensing element.

In an embodiment of the present invention, the above-mentioned first area has a first through hole, and the reflected light beam reflected by the finger passes through the first through hole to be transmitted to the image sensing element.

In an embodiment of the present invention, the above-mentioned under-screen fingerprint recognition device further includes at least one optical film layer disposed on the diffusion layer. At least one optical film layer has a third area and a fourth area, wherein in a direction perpendicular to the extension of the display module, the position of the third area corresponds to the first area, the position of the fourth area corresponds to the second area, and the position of the third area corresponds to the second area, and the The transmittance of the third area to infrared light is greater than the transmittance of the fourth area to infrared light.

In an embodiment of the present invention, a first gain layer is arranged on the surface of the above-mentioned first region, the refractive index of the first gain layer matches the refractive index of the first region, and in each at least one optical film layer, the first A second gain layer is arranged on the surface of the three areas, the refractive index of the second gain layer matches the refractive index of the third area, and the reflected light beam reflected by the finger passes through the second gain layer and the first gain layer to the image sensor element.

In an embodiment of the present invention, in each of the at least one optical film layer, the first region has a first perforation, the third region has a second perforation, and the reflected beam reflected by the finger passes through the first perforation and the second perforation. perforated and transferred to the image sensing element.

In an embodiment of the present invention, the third region of the at least one optical film layer has an asymmetric optical microstructure.

In an embodiment of the present invention, the third region of the at least one optical film layer is a flat surface.

In an embodiment of the present invention, the above-mentioned under-screen fingerprint recognition device further includes a pair of infrared absorbing layers, and the diffusion layer is disposed between the pairs of infrared absorbing layers. The layer does not cover the first region of the diffusion layer.

In an embodiment of the present invention, the material of the first region of the diffusion layer is different from the material of the second region.

Based on the above, in the under-display fingerprint recognition device of the present invention, the display module is disposed above the image sensing element, and the diffusion layer in the display module has a first area and a second area, wherein the position of the finger pressing area overlaps The image sensing element and the first region of the diffusion layer. The image sensing element is adapted to receive the reflected beam reflected by the finger and transmitted through the first area, and the transmittance of the first area to the reflected beam is greater than the transmittance of the second area to the reflected beam. In this way, the user can directly perform off-screen fingerprint sensing by pressing the display area of the display module, and at the same time, the display module has a good display effect.

In order to make the above-mentioned features and advantages of the present invention more comprehensible, the following specific embodiments are described in detail together with the accompanying drawings.

FIG. 1 is a schematic top view of an under-display fingerprint recognition device according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of the under-screen fingerprint recognition device of FIG. 1 . Please refer to Figure 1 and Figure 2. The present embodiment provides an under-screen fingerprint identification device 10 , such as an electronic device with a liquid-crystal display (LCD). For example, the under-display fingerprint identification device 10 of this embodiment is a smart phone, but the present invention is not limited thereto.

The under-screen fingerprint recognition device 10 is suitable for sensing the finger 20 , and includes an image sensing element 50 and a display module 100 , wherein the display module 100 is configured on the image sensing element 50 . In other words, the image sensing element 50 is disposed below the display module 100 . Therefore, when performing fingerprint identification under the screen, the user can place the finger 20 on the display module 100, and the image sensor 50 located under the display module 100 receives the reflected sensing light from the finger 20 to perform fingerprint identification. .

The image sensing element 50 is, for example, a photosensitive element such as a charge coupled device (CCD) or a complementary metal oxide semiconductor transistors (CMOS) for receiving light signals.

The display module 100 is, for example, a liquid crystal display module. In this embodiment, the display module 100 includes a light source module 110 , a diffusion layer 120 and a light-transmitting protective layer 140 . In this embodiment, the light source module 110 is, for example, an edge-type backlight module or a direct-type backlight module including a light emitting element (such as an LED light bar) and a light guide plate, but the invention is not limited thereto.

The diffusion layer 120 is disposed on the light source module 110 to make the passing display light distribution more uniform. In this embodiment, the diffusion layer 120 includes diffusion particles, for example. For example, the diffusion particles are polystyrene, polymethacrylate, methyl methacrylate and styrene copolymer, polycarbonate, polyethylene, silicone, calcium carbonate, silicon dioxide, titanium dioxide or combinations thereof, but the present invention is not limited thereto.

The light-transmitting protective layer 140 is disposed on the diffusion layer 120 and has a finger pressing area A, which is suitable for the user to press with the finger 20 for fingerprint identification. The light-transmitting protection layer 140 is, for example, light-transmitting glass or light-transmitting plastic, and the present invention is not limited thereto.

In this embodiment, the diffusion layer 120 has a first region B1 and a second region B2. In the direction perpendicular to the extension of the display module 100 (that is, the direction D in FIG. 2 ), the position of the finger pressing area A overlaps the first area B1 of the image sensing element 50 and the diffusion layer 120, and the finger pressing area A does not Overlapping the second area B2. In other words, the position of the first area B1 corresponds to the finger pressing area A. As shown in FIG.

In this embodiment, however, the image sensing element 50 is adapted to receive the reflected light beam L reflected by the finger 20 and passed through the first area B1, and the transmittance of the first area B1 to infrared light is greater than that of the second area B2 to infrared light transmittance. Specifically, in the manufacturing process of the diffusion layer 120 in this embodiment, different materials, flatness, geometric shape, coating or structural symmetry and other factors that can change the optical effect can be further used to manufacture the first layer with different optical characteristics. The first region B1 and the second region B2, for example, the first region B1 has an asymmetric optical microstructure or is a flat surface. In this way, the user can directly perform off-screen fingerprint sensing by pressing the display area of the display module 100 , and at the same time, the display module 100 has a good display effect. For example, in one embodiment, a first gain layer (not shown) may be disposed on the surface of the first region B1, and the refractive index of the first gain layer matches the refractive index of the first region B1, and the The reflected light beam L reflected by 20 passes through the first gain layer to the image sensing element 50 .

Alternatively, in this embodiment, the under-display fingerprint recognition device 10 may further include at least one optical film layer 130 (for example, an upper brightness enhancement film 132 and a lower brightness enhancement film 134 ), disposed on the diffusion layer 120, and at least one optical film layer 130 has a third area B3 and a fourth area B4, wherein in the direction perpendicular to the extension of the display module 100 (that is, the direction D in FIG. 2 ), the position of the third area B3 corresponds to the first area B1, and the fourth area The position of B4 corresponds to the second area B2, and the transmittance of the third area B3 to infrared light is greater than the transmittance of the fourth area B4 to infrared light. In other words, in this embodiment, in addition to the diffusion layer 120 , the optical film layer 130 can be further optically designed during the manufacturing process to improve a good sensing effect, but the present invention is not limited thereto.

Specifically, in the manufacturing process of the optical film layer 130 of this embodiment, different materials, flatness, geometric shape, coating or structural symmetry and other factors that can change the optical effect can be further used to manufacture optical films with different optical characteristics. The third region B3 and the fourth region B4, for example, the third region B3 has an asymmetric optical microstructure or is a flat surface. In this way, the user can directly perform off-screen fingerprint sensing by pressing the display area of the display module 100 , and at the same time, the display module 100 has a good display effect. For example, in another embodiment, a second gain layer (not shown) may be disposed on the surface of the third region B3, and the refractive index of the second gain layer matches the refractive index of the third region B3, and by The reflected light beam L reflected by the finger 20 passes through the second gain layer and the first gain layer to the image sensing element 50 .

The display module 100 further includes a reflective layer 150 disposed between the light source module 110 and the image sensing element 50 , adapted to reflect light leakage from the light source module 110 to improve the display effect of the display module 100 . In this embodiment, the reflective layer 150 can reflect visible light and allow infrared light to pass through the material or structural design, but the present invention is not limited thereto.

FIG. 3 is a schematic cross-sectional view of an under-display fingerprint recognition device according to another embodiment of the present invention. Please refer to Figure 3. The under-display fingerprint recognition device 10A of this embodiment is similar to the under-display fingerprint recognition device 10 shown in FIG. 2 . The difference between the two is that, in this embodiment, the first area B1 of the diffusion layer 120A has a first through hole H through which the reflected beam L reflected by the finger 20 passes through the first through hole H to be transmitted to the image sensing element 50 . Therefore, the transmission effect of the reflected light beam L in the first area B1 can be further improved, and a good optical signal intensity can be maintained. In this way, the user can directly perform off-screen fingerprint sensing by pressing the display area of the display module 100A, and at the same time, the display module 100A has a good display effect. Furthermore, in another embodiment, in addition to the first through hole H in the first region B1, in each at least one optical film layer 130, the third region B3 may also have a second through hole (not shown), And the reflected light beam L reflected by the finger 20 passes through the first through hole H and the second through hole H2 to be transmitted to the image sensing element 50 .

Besides, in this embodiment, the under-screen fingerprint recognition device 10A further includes a pair of infrared absorbing layers 160 , and the diffusion layer 120 is disposed between the pair of infrared absorbing layers 160 . The infrared absorbing layer 160 is, for example, a thin film or a coating film formed on the diffusion layer 120 , and the invention is not limited thereto. In one embodiment, the pair of infrared absorbing layers 160 does not cover the first region B1 of the diffusion layer 120 in the direction perpendicular to the extension of the display module 100 (ie, the direction D in FIG. 3 ). In this embodiment, the pair of infrared absorbing layers 160 does not cover the first through hole H in the first region B1. That is, the infrared absorbing layer 160 can also be designed to have perforations, so that the reflected light beam L reflected by the finger 20 passes through and has a good light intensity signal. In this way, the user can directly perform off-screen fingerprint sensing by pressing the display area of the display module 100A, and at the same time, the display module 100A has a good display effect.

In this embodiment, the under-screen fingerprint recognition device 10A further includes a light emitting element 170 disposed adjacent to the image sensing element 50 . The light emitting element 170 is adapted to provide a sensing light beam (not shown) to illuminate the finger pressing area A of the light-transmitting protective layer 140 . The light emitting element 170 is, for example, an infrared light emitting diode, but the present invention is not limited thereto. In some embodiments, it is possible to further increase the design of improving the infrared light transmission effect for the position of the diffusion layer 120A and the optical film layer 130 corresponding to the light-emitting element 170, such as changing the material, forming a coating, configuring a thin film, or designing a perforation, etc., the present invention It is not limited to this.

In summary, in the under-display fingerprint recognition device of the present invention, the display module is disposed above the image sensing element, and the diffusion layer in the display module has a first area and a second area, wherein the position of the finger pressing area overlapping with the image sensing element and the first region of the diffusion layer. The image sensing element is adapted to receive the reflected beam reflected by the finger and transmitted through the first area, and the transmittance of the first area to the reflected beam is greater than the transmittance of the second area to the reflected beam. In this way, the user can directly perform off-screen fingerprint sensing by pressing the display area of the display module, and at the same time, the display module has a good display effect.

Although the present invention has been disclosed above with the embodiments, it is not intended to limit the present invention. Anyone with ordinary knowledge in the technical field may make some changes and modifications without departing from the spirit and scope of the present invention. The scope of protection of the present invention should be defined by the scope of the appended patent application.

10,10A: Under-screen fingerprint recognition device 20: fingers 50: Image sensing element 100,100A: display module 110:Light source module 120, 120A: diffusion layer 130: Optical film layer 132: Upper brightness enhancement film 134: lower brightness enhancement film 140: light-transmitting protective layer 150: reflective layer 160: infrared absorbing layer 170: Light emitting element A: Finger press area B1: the first area B2: Second area B3: The third area B4: The fourth area D: Direction H: first piercing L: reflected beam

FIG. 1 is a schematic top view of an under-display fingerprint recognition device according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of the under-screen fingerprint recognition device of FIG. 1 . FIG. 3 is a schematic cross-sectional view of an under-display fingerprint recognition device according to another embodiment of the present invention.

10A: Under-screen fingerprint recognition device

20: fingers

50: Image sensing element

100A: display module

110:Light source module

120A: Diffusion layer

130: Optical film layer

132: Upper brightness enhancement film

134: lower brightness enhancement film

140: light-transmitting protective layer

150: reflective layer

160: infrared absorbing layer

170: Light emitting element

A: Finger press area

B1: the first area

B2: Second area

B3: The third area

B4: The fourth area

D: Direction

H: first piercing

L: reflected beam

Claims (9)

An under-screen fingerprint recognition device, suitable for sensing fingers, comprising: an image sensing element; and a display module configured on the image sensing element, the display module comprising: a light source module; a diffusion layer configured on the In the light source module, the diffusion layer has a first area and a second area; and a light-transmitting protective layer, configured on the diffusion layer, has a finger pressing area, wherein in the direction perpendicular to the extension of the display module , the position of the finger pressing area overlaps the image sensing element and the first area of the diffusion layer, and the finger pressing area does not overlap the second area, and the image sensing element is suitable for receiving the reflected beam reflected by the finger and passing through the first area, and the transmittance of the first area to the reflected beam is greater than the transmittance of the second area to the reflected beam, wherein, The under-screen fingerprint recognition device further includes: a pair of infrared absorbing layers, the diffusion layer is arranged between the pair of infrared absorbing layers, wherein in the direction perpendicular to the extension of the display module, the pair of infrared absorbing layers A layer does not cover the first region of the diffusion layer. The under-screen fingerprint recognition device according to claim 1, wherein a first gain layer is disposed on the surface of the first region, the refractive index of the first gain layer matches the refractive index of the first region, and by The reflected light beam reflected by the finger passes through the first gain layer to the image sensing element. The under-screen fingerprint recognition device according to claim 1, wherein the first region has a first perforation, and the reflected light beam reflected by the finger passes through the first perforation and is transmitted to the image sensing element . The under-display fingerprint recognition device according to claim 1, further comprising: at least one optical film layer disposed on the diffusion layer, the at least one optical film layer has a third area and a fourth area, wherein In the extending direction of the display module, the position of the third area corresponds to the first area, the position of the fourth area corresponds to the second area, and the transmission of infrared light by the third area The ratio is greater than the transmittance of the fourth region to infrared light. The under-screen fingerprint recognition device according to claim 4, wherein a first gain layer is disposed on the surface of the first region, the refractive index of the first gain layer matches the refractive index of the first region, and In the at least one optical film layer, a second gain layer is arranged on the surface of the third region, the refractive index of the second gain layer matches the refractive index of the third region, and all the reflections reflected by the finger The reflected light beam passes through the second gain layer and the first gain layer to the image sensing element. The fingerprint recognition device under the screen according to claim 4, wherein in the at least one optical film layer, the first region has a first perforation, and the third region has a second perforation, and is reflected by the finger The reflected light beam passes through the first through hole and the second through hole to the image sensing element. The under-screen fingerprint recognition device according to claim 4, wherein the third region of the at least one optical film layer has an asymmetric optical microstructure. The under-display fingerprint recognition device according to claim 4, wherein the third region of the at least one optical film layer is a flat surface. The under-display fingerprint recognition device according to claim 1, wherein the material of the first region of the diffusion layer is different from the material of the second region.

Images