TWI773406B - Under-screen identification display apparatus - Google Patents

Abstract

An under-screen identification display apparatus is suitable for generating an image ray under the irradiation of an external ray and includes a first substrate, a second substrate, a liquid crystal layer, a reflective layer, a photonic crystal layer and a fingerprint recognition module. The second substrate is disposed opposite to the first substrate. The liquid crystal layer is disposed between the first substrate and second substrate. The reflective layer is disposed between the first substrate and the liquid crystal layer and is used to reflect a part of the external ray to generate the image ray. The photonic crystal layer is disposed between the first substrate and the liquid crystal layer, and does not overlap the reflective layer. The fingerprint recognition module is disposed on a side of the first substrate away from the liquid crystal layer and overlaps the photonic crystal layer. The fingerprint recognition module is suitable for emitting an illumination ray toward the photonic crystal layer. The photonic crystal layer is suitable for passing the illumination ray and reflecting another part of the external ray.

Description

Display device for under-screen recognition

The present invention relates to a display device, and more particularly, to a display device for under-screen identification with a fingerprint identification function.

In order to increase the screen-to-body ratio of the display to achieve a narrow bezel design, under-screen fingerprint recognition technology has become a trend. To put it simply, the under-screen fingerprint identification technology is to dispose the fingerprint identification module below the display panel of the electronic device. After the electronic device detects that the user touches the display screen, the electronic device controls the display panel to emit light to illuminate the surface of the user's finger. The light can be reflected by the user's finger (diffusely) into the fingerprint identification module under the display panel, and the fingerprint identification module converts the reflected light into a digital image signal, and then the user's fingerprint image can be obtained.

Most of the current display devices with fingerprint identification function integrate the fingerprint identification module into a backlight module or an additional shading panel. However, such a method increases the overall thickness of the display device, and the visibility of the fingerprint identification module reduces the display quality of the display device. Therefore, the flexibility of setting the fingerprint identification module in the display area is reduced.

The present invention provides a display device for under-screen identification with a fingerprint identification function, which has a thinner overall thickness and better display quality.

The display device for under-screen recognition of the present invention is suitable for generating image light under the irradiation of external light. The display device for under-screen identification includes a first substrate, a second substrate, a liquid crystal layer, a reflective layer, a photonic crystal layer and a fingerprint identification module. The second substrate is disposed opposite to the first substrate. The liquid crystal layer is disposed between the first substrate and the second substrate. The reflection layer is disposed between the first substrate and the liquid crystal layer, and is used for reflecting a part of external light to generate image light. The photonic crystal layer is arranged between the first substrate and the liquid crystal layer, and does not overlap the reflective layer. The fingerprint identification module is arranged on the side of the first substrate away from the liquid crystal layer, and overlaps the photonic crystal layer. The fingerprint identification module is suitable for emitting illumination light toward the photonic crystal layer. The photonic crystal layer is adapted to pass the illumination light and reflect another part of the external light.

In an embodiment of the present invention, the above-mentioned display device for under-screen recognition further includes an active element layer disposed on the first substrate, and the reflective layer is electrically connected to the active element layer.

In an embodiment of the present invention, the above-mentioned display device for under-screen recognition further includes a color filter layer. The color filter layer is overlapped and arranged on the reflective layer, and is located between the liquid crystal layer and the reflective layer. The photonic crystal layer does not overlap the reflective layer and the color filter layer. The thickness of the color filter layer and the reflective layer in a stacking direction is equal to the thickness of the photonic crystal layer in the stacking direction.

In an embodiment of the present invention, the photonic crystal layer of the above-mentioned under-screen recognition display device includes a first photonic crystal pattern, a second photonic crystal pattern and a third photonic crystal pattern suitable for reflecting light of different colors.

In an embodiment of the present invention, the first photonic crystal pattern, the second photonic crystal pattern, and the third photonic crystal pattern of the above-mentioned under-screen recognition display device are respectively used to reflect wavelengths ranging from 630 nm to 750 nm. Red light, green light with wavelengths ranging from 490 nm to 570 nm, and blue light with wavelengths ranging from 440 nm to 470 nm.

In an embodiment of the present invention, the orthographic projections of the first photonic crystal pattern, the second photonic crystal pattern and the third photonic crystal pattern on the first substrate of the above-mentioned under-screen recognition display device do not overlap each other.

In an embodiment of the present invention, the orthographic projections of the first photonic crystal pattern, the second photonic crystal pattern and the third photonic crystal pattern of the above-mentioned under-screen recognition display device on the first substrate overlap with each other.

In an embodiment of the present invention, the above-mentioned display device for under-screen recognition further includes a light guide plate and a light source. The light guide plate is arranged on the side of the second substrate away from the liquid crystal layer, and has a light emitting surface facing the reflective layer and a light incident surface connected to the light emitting surface. The light source is arranged on one side of the light incident surface of the light guide plate.

In an embodiment of the present invention, the reflective layer of the above-mentioned under-screen recognition display device is another photonic crystal layer.

In an embodiment of the present invention, the reflective layer and the photonic crystal layer of the above-mentioned under-screen recognition display device are integrated.

In an embodiment of the present invention, the above-mentioned display device for under-screen recognition further includes a plurality of light-transmitting conductive patterns, which are disposed on the photonic crystal layer overlappingly. The reflective layer is a plurality of reflective electrodes, and the light-transmitting conductive patterns are electrically connected to the reflective electrodes respectively.

In an embodiment of the present invention, the external light of the display device identified under the screen is visible light, and the illumination light is infrared light.

Based on the above, in the display device for under-screen identification according to an embodiment of the present invention, a fingerprint identification module is disposed on the side of the first substrate away from the liquid crystal layer, and a photonic crystal layer is disposed between the first substrate and the liquid crystal layer. Through the overlapping relationship between the photonic crystal layer and the fingerprint identification module, the flexibility of setting the fingerprint identification module in the display area can be increased, and the display quality of the display device identified under the screen can be prevented from deteriorating due to the fingerprint identification module. On the other hand, since the display device for under-screen recognition of the present invention can effectively reduce the visibility of the fingerprint recognition module without setting an additional light shield, it can also have a thinner and lighter appearance.

The foregoing and other technical contents, features and effects of the present invention will be clearly presented in the following detailed description of a preferred embodiment with reference to the drawings. The directional terms mentioned in the following embodiments, such as: up, down, left, right, front or rear, etc., are only for referring to the directions of the attached drawings. Accordingly, the directional terms used are illustrative and not limiting of the present invention.

1 is a schematic cross-sectional view of a display device for under-screen recognition according to a first embodiment of the present invention. FIG. 2 is a schematic top view of the photonic crystal layer of FIG. 1 . FIG. 3 is a schematic top view of a photonic crystal layer according to another embodiment of the present invention. 4 is a schematic top view of a photonic crystal layer according to still another embodiment of the present invention.

Referring to FIG. 1 and FIG. 2 , the display device 10 recognized under the screen includes a first substrate 101 , a second substrate 102 , an active element layer 105 , a liquid crystal layer 110 and a reflective layer 120 . The first substrate 101 and the second substrate 102 are disposed opposite to each other. The liquid crystal layer 110 is disposed between the first substrate 101 and the second substrate 102 . The reflective layer 120 is disposed on the first substrate 101 and located between the first substrate 101 and the liquid crystal layer 110 . The active element layer 105 is disposed on the first substrate 101 and located between the liquid crystal layer 110 and the first substrate 101 . In this embodiment, the reflective layer 120 is, for example, a plurality of reflective electrodes RE. The reflective electrodes RE are electrically connected to the first substrate 101 . The plates of the first substrate 101 and the second substrate 102 can be made of glass, quartz, or high molecular polymers (such as polycarbonate, polyimide or polyethylene terephthalate), but not limit.

For example, a plurality of scan lines (not shown) and a plurality of data lines (not shown) may also be disposed on the first substrate 101 , and the active element layer 105 may have a plurality of switching elements (not shown). Each of the switching elements is electrically connected to a corresponding scan line and a corresponding data line. The plurality of reflective electrodes RE of the reflective layer 120 are respectively electrically connected to the switching elements (ie, the active element layer 105 ). The switching elements here are, for example, thin film transistors, or other suitable active elements. On the other hand, the display device 10 for under-screen recognition may further include a common electrode layer (not shown) and a polarizer (not shown) respectively disposed on opposite side surfaces of the second substrate 102 , wherein the common electrode layer is located on the opposite side of the second substrate 102 . between the liquid crystal layer 110 and the second substrate 102, but not limited thereto.

The electric field generated when the common electrode layer and the reflective electrodes RE are enabled can drive a plurality of liquid crystal molecules (not shown) of the liquid crystal layer 110 to rotate, so as to modulate the polarization state of incident light (eg, external light EB). ). In this embodiment, the display device 10 for under-screen recognition is, for example, a reflective display device for under-screen recognition, which is suitable for generating image light IMB under the irradiation of external light EB. For example, the display device 10 for under-screen recognition can individually control the potentials of the reflective electrodes RE through the scan lines, the data lines and the switching elements according to the screen image to be presented, so that the external light EB passes through the liquid crystal layer 110 twice and Image rays IMB with different polarization states are formed after reflection by these reflective electrodes RE. The image light IMB has a corresponding light intensity after passing through the aforementioned polarizer, and forms an image on the retina of the human eye.

It should be noted that the present invention is not limited to the driving mode of the liquid crystal layer 110 , for example, the liquid crystal layer 110 may adopt an electrically controlled birefringence (ECB) liquid crystal mode, an optically compensated birefringence (OCB) Liquid crystal mode, Vertical Alignment (VA) liquid crystal mode, Fringe-Field Switching (FFS) liquid crystal mode, In-Plane Switching (IPS) liquid crystal mode, twisted nematic ( Twisted Nematic, TN) liquid crystal mode or super twisted nematic (Super-Twisted Nematic, STN) liquid crystal mode.

Since the electrode configuration of the display device 10 for under-screen recognition depends on the driving mode adopted by the liquid crystal layer 110, the present invention is not limited thereto. For example, in other not shown embodiments, the electrode layer and the reflective layer 120 on the first substrate 101 may also belong to different film layers. Alternatively, the common electrode layer may also be disposed on the first substrate 101 instead.

In order to enable the display device 10 for under-screen identification to have the function of fingerprint identification, the display device 10 for under-screen identification further includes a photonic crystal layer 130 and a fingerprint identification module 200 . In detail, the first substrate 101 has a first surface 101a facing the liquid crystal layer 110 and a second surface 101b opposite to the first surface 101a. The photonic crystal layer 130 and the fingerprint identification module 200 are respectively disposed on the first surface 101 a and the second surface 101 b of the first substrate 101 . That is, the fingerprint recognition module 200 is disposed on the side of the first substrate 101 away from the liquid crystal layer 110 , and the photonic crystal layer 130 is disposed between the first substrate 101 and the liquid crystal layer 110 .

In this embodiment, the fingerprint identification module 200 and the photonic crystal layer 130 are disposed between the plurality of reflective electrodes RE, and overlap each other along the direction Z. For example, the fingerprint recognition module 200 may have a plurality of recognition units 200U, and the recognition units 200U and the plurality of reflective electrodes RE are alternately arranged in at least one direction (eg, the direction X) of the vertical direction Z, but this is not the case limit.

The fingerprint identification unit 200U is adapted to emit illumination light IB toward the photonic crystal layer 130 . The illumination light IB forms a fingerprint image light IB' after (diffuse) reflection on the fingerprint surface of the finger FG and transmits it back to the corresponding fingerprint recognition unit 200U. It is particularly noted that the photonic crystal layer 130 disposed on the transmission path of the illumination light IB is suitable for allowing the illumination light IB and the fingerprint image light IB' to pass, and reflecting a part of the external light EB (eg, the external light EB1). In addition to ensuring the normal operation of the fingerprint identification, the concealment of the fingerprint identification module 200 under the irradiation of the external light EB can also be increased. In this embodiment, the illumination light IB is, for example, infrared light, and the external light EB is, for example, visible light.

Further, the photonic crystal layer 130 may selectively include a plurality of photonic crystal patterns, for example, a first photonic crystal pattern 131 , a second photonic crystal pattern 132 and a third photonic crystal pattern 133 . These photonic crystal patterns are suitable for reflecting light of different colors. In this embodiment, the first photonic crystal pattern 131 , the second photonic crystal pattern 132 and the third photonic crystal pattern 133 are disposed between any two adjacent display pixel areas PA, and these photonic crystal patterns are located in the first The orthographic projections on the substrate 101 do not overlap with each other, but not limited thereto. For example, the first photonic crystal pattern 131 , the second photonic crystal pattern 132 and the third photonic crystal pattern 133 can be used to reflect red light with wavelengths ranging from 630 nm to 750 nm, and wavelengths ranging from 490 nm to 750 nm, respectively. Green light at 570 nm and blue light with wavelengths ranging from 440 nm to 470 nm, but not limited thereto.

Since these photonic crystal patterns do not overlap each other in the transmission direction of light, part of the visible light can still pass through the photonic crystal layer 130 . In order to reduce the visibility of the fingerprint identification module 200, a visible light absorption layer (not shown) may be provided around the fingerprint identification module 200, but not limited thereto. In other embodiments, an absorption filter layer may be disposed between the photonic crystal layer 130 and the fingerprint identification module 200 , and the absorption filter layer has the characteristics of absorbing visible light and allowing infrared light to pass through.

It is particularly mentioned that the display device 10 for under-screen recognition may also selectively include a plurality of light-transmitting conductive patterns 150 , and these light-transmitting conductive patterns 150 overlap with the photonic crystal layer 130 in the direction Z. As shown in FIG. The material of the light-transmitting conductive pattern 150 includes, for example, metal oxides, such as indium tin oxide, indium zinc oxide, aluminum tin oxide, aluminum zinc oxide, or other suitable oxides, or a stack of at least two of the above. Floor.

In this embodiment, the light-transmitting conductive patterns 150 are respectively electrically connected to the plurality of reflective electrodes RE of the reflective layer 120 . Therefore, the portion of the liquid crystal layer 110 overlapping the photonic crystal layer 130 along the direction Z can also be driven by the electric field. That is to say, the polarization state of the external light EB1 reflected by the photonic crystal layer 130 can be modulated after passing through the liquid crystal layer 110 again, so that the area between the reflective electrodes RE can also be switched between bright and dark states to achieve The effect of color display. From another point of view, the reflective electrode RE and the light-transmitting conductive pattern 150 that are adjacent to each other and electrically connected can define the display pixel area PA of the display device 10 recognized under the screen.

It should be noted that the present invention does not limit the arrangement of the light-transmitting conductive patterns 150. For example, in other embodiments, the light-transmitting conductive patterns 150 can also be arranged between the photonic crystal layer 130 and the first substrate 101. And directly cover the adjacent reflective electrodes RE.

In this embodiment, the photonic crystal patterns may have a plurality of columnar structures, and the columnar structures are respectively arranged at a specific pitch along at least two directions. In this embodiment, the columnar structures are arranged along the direction X and the direction Y respectively, and the direction X is substantially perpendicular to the direction Y, but not limited thereto. In other embodiments, the columnar structures can also be arranged at a specific pitch along three mutually intersecting and coplanar directions, for example, a honeycomb arrangement. In this embodiment, the orthographic profile of the columnar structures on the first substrate 101 may be square, but not limited thereto. In other embodiments, the orthographic profile of the columnar structure of the photonic crystal pattern on the first substrate 101 may also be a circle or other suitable shapes.

For example, the plurality of columnar structures 131p of the first photonic crystal pattern 131 each have a width Wa, and are arranged with a pitch Pa along the direction X and the direction Y, respectively. The plurality of columnar structures 132p of the second photonic crystal pattern 132 each have a width Wb, and are arranged with a pitch Pb along the direction X and the direction Y, respectively. The plurality of columnar structures 133p of the third photonic crystal pattern 133 each have a width Wc, and are arranged with a pitch Pc along the direction X and the direction Y, respectively. It is important to note that these photonic crystal patterns used to reflect light of different colors have different columnar structure widths and arrangement pitches.

In this embodiment, regardless of whether the order is based on the width of the columnar structures or the arrangement pitch, the width Wa and arrangement pitch Pa of the first photonic crystal pattern 131 are both the largest, and the second photonic crystal pattern 132 has the largest width Wa and arrangement pitch Pa. The width Wb and the arrangement pitch Pb are next, and both the width Wc and the arrangement pitch Pc of the third photonic crystal pattern 133 are the smallest. The columnar structure material of the photonic crystal pattern here includes silicon, such as single-crystalline silicon or polycrystalline silicon.

Through the optical properties of the photonic crystal layer 130 and the overlapping relationship with the fingerprint identification module 200 , in addition to increasing the flexibility of the fingerprint identification module 200 in the display area of the display device 10 for under-screen identification, it can also avoid under-screen identification. The display device 10 of the present invention is provided with the fingerprint identification module 200 and the display quality is degraded.

It should be noted that the present invention is not limited to the configuration and fabrication material of the periodic structure of the photonic crystal layer. In other embodiments, the periodic structures of the multiple photonic crystal patterns (eg, the first photonic crystal pattern 131A, the second photonic crystal pattern 132A, and the third photonic crystal pattern 133A) of the photonic crystal layer 130A may also be multiple holes. (The holes 131h, the holes 132h and the holes 133h shown in FIG. 3 ), and the materials used are, for example, metal materials or other suitable dielectric materials. On the other hand, the present invention does not limit the arrangement of a plurality of photonic crystal patterns. For example, in other embodiments, in order to make the reflection effect of red light greater than the reflection effect of green light and blue light, any two adjacent display images Two first photonic crystal patterns 131B, one second photonic crystal pattern 132B and one third photonic crystal pattern 133B of the photonic crystal layer 130B may be disposed between the pixel areas PA (as shown in FIG. 4 ).

In this embodiment, the display device 10 for under-screen recognition may optionally further include a color filter layer 140 disposed between the liquid crystal layer 110 and the reflective layer 120 . The color filter layer 140 is overlapped with the reflective layer 120 . It is particularly noted that the photonic crystal layer 130 does not overlap the color filter layer 140 and the reflective layer 120 along the stacking direction (eg, the direction Z) of the color filter layer 140 and the reflective layer 120 , and the color filter layer 140 and the reflective layer 120 do not overlap. The thickness T1 of the layer 120 in the stacking direction is substantially equal to the thickness T2 of the photonic crystal layer 130 in the stacking direction. Accordingly, the uniformity of the film thickness of the liquid crystal layer 110 is ensured, and the deterioration of the display quality due to the arrangement of the photonic crystal layer 130 is avoided.

Another part of the external light EB (eg, the external light EB2 ) forms light of different colors through the color filter layer 140 , thereby achieving the effect of color display. For example, the color filter layer 140 may include a plurality of red filter patterns, a plurality of green filter patterns, and a plurality of blue filter patterns, and these filter patterns respectively overlap with the plurality of the reflective layers 120 along the direction Z. a reflective electrode RE. The external light EB2 can respectively form red light, green light and blue light after passing through these filter patterns. However, the present invention is not limited to this. In other embodiments, the display device for under-screen recognition may not be provided with the color filter layer 140 .

Hereinafter, other embodiments will be listed to describe the present disclosure in detail, wherein the same components will be marked with the same symbols, and the description of the same technical content will be omitted.

5 is a schematic cross-sectional view of a display device for under-screen recognition according to a second embodiment of the present invention. Referring to FIG. 5 , the difference between the display device 10A recognized under the screen of this embodiment and the display device 10 recognized under the screen of FIG. 1 is that the arrangement of the photonic crystal patterns of the photonic crystal layer is different. In this embodiment, the first photonic crystal pattern 131C, the second photonic crystal pattern 132C and the third photonic crystal pattern 133C of the photonic crystal layer 130C are, for example, along the normal direction of the first surface 101a of the first substrate 101 (for example, direction Z) stacking settings. That is, the orthographic projections of these photonic crystal patterns on the first substrate 101 overlap with each other. Accordingly, the reflection areas of these photonic crystal patterns for light of different colors can be increased.

Since the first photonic crystal pattern 131C, the second photonic crystal pattern 132C and the third photonic crystal pattern 133C of the present embodiment are similar to the first photonic crystal pattern 131 , the second photonic crystal pattern 132 and the third photonic crystal pattern of the embodiment of FIG. 2 Pattern 133. Therefore, for a detailed description, please refer to the relevant paragraphs of the foregoing embodiments, which will not be repeated here.

In this embodiment, the external light EB1 is composed of, for example, a plurality of different colors of light, for example: a first color light EB1a (eg, red light), a second color light EB1b (eg, green light), and a third color light EB1c (for example, Blu-ray). When the external light EB1 is transmitted to the interface between the first photonic crystal pattern 131C and the liquid crystal layer 110, the first color light EB1a is reflected. When the external light EB1 is transmitted to the interface between the first photonic crystal pattern 131C and the second photonic crystal pattern 132C, the second color light EB1b will be reflected. By analogy, when the external light EB1 is transmitted to the interface between the second photonic crystal pattern 132C and the third photonic crystal pattern 133C, the third color light EB1c will be reflected.

That is to say, the external light EB1 cannot pass through the photonic crystal layer 130C, thereby effectively reducing the visibility of the fingerprint identification module 200 . From another point of view, since the display device 10A for under-screen recognition can effectively reduce the visibility of the fingerprint recognition module 200 without an additional shading plate, it can also have a thinner and lighter appearance.

6 is a schematic cross-sectional view of a display device for under-screen recognition according to a third embodiment of the present invention. Referring to FIG. 6 , the difference between the display device 20 identified under the screen of this embodiment and the display device 10 identified under the screen in FIG. 1 is that the display device 20 identified under the screen can optionally include a front light module. For example, the front light module includes a light guide plate 180 and a light source 190 . The light guide plate 180 is disposed on the side of the second substrate 102 away from the liquid crystal layer 110 and has a light exit surface 180e facing the reflective layer 120 and a light incident surface 180i connected to the light exit surface 180e. The light source 190 is disposed on one side of the light incident surface 180i of the light guide plate 180 .

In this embodiment, the light source 190 is used to provide the illumination light FIB. The illuminating light FIB is transmitted laterally inside the light guide plate 180 and then exits from the light guide plate 180 in the direction of the reflective layer 120 or the photonic crystal layer 130 . Through the arrangement of the front light module, the display device 20 identified under the screen can have a good display quality even in the night or in a darker use environment.

7 is a schematic cross-sectional view of a display device for under-screen recognition according to a fourth embodiment of the present invention. Referring to FIG. 7 , the difference between the display device 30 for under-screen identification in this embodiment and the display device 10 for under-screen identification in FIG. 1 is that the configurations of the photonic crystal layer and the fingerprint identification module are different. In this embodiment, the photonic crystal layer 130D of the display device 30 for under-screen recognition extends over the entire surface between the liquid crystal layer 110 and the first substrate 101 . That is to say, the combination of the reflective layer 120 and the color filter layer 140 in FIG. 1 can also be replaced by another photonic crystal layer, and the other photonic crystal layer is integrated with the photonic crystal layer 130 in FIG. 1 to form the present invention. Photonic crystal layer 130D of an embodiment.

Correspondingly, the fingerprint recognition module 200A of this embodiment can also be distributed on the second surface 101 b of the first substrate 101 over the entire surface. Accordingly, the operation flexibility of the display device 30 for under-screen recognition during fingerprint recognition can be increased. For example, the user can perform fingerprint identification anywhere on the display screen. Since the composition and configuration of the photonic crystal layer 130D of this embodiment are similar to the photonic crystal layer 130 of FIG. 2 , the photonic crystal layer 130A of FIG. 3 , the photonic crystal layer 130B of FIG. 4 or the photonic crystal layer 130C of FIG. , please refer to the relevant paragraphs of the foregoing embodiments for detailed description, which will not be repeated here.

On the other hand, different from the display device 10 identified under the screen of FIG. 1 , the plurality of light-transmitting conductive patterns 150A of this embodiment can define a plurality of display pixel areas PA' of the display device 30 identified under the screen.

To sum up, in the display device for under-screen identification according to an embodiment of the present invention, a fingerprint identification module is disposed on the side of the first substrate away from the liquid crystal layer, and a photonic crystal layer is disposed between the first substrate and the liquid crystal layer. . Through the overlapping relationship between the photonic crystal layer and the fingerprint identification module, the flexibility of setting the fingerprint identification module in the display area can be increased, and the display quality of the display device identified under the screen can be prevented from deteriorating due to the fingerprint identification module. On the other hand, since the display device for under-screen recognition of the present invention can effectively reduce the visibility of the fingerprint recognition module without setting an additional light shield, it can also have a thinner and lighter appearance.

10, 10A, 20, 30: Display devices identified under the screen 101: The first substrate 101a: First surface 101b: Second surface 102: Second substrate 105: Active component layer 110: Liquid crystal layer 120: Reflective layer 130, 130A, 130B, 130C, 130D: photonic crystal layer 131, 132, 133, 131A, 132A, 133A, 131B, 132B, 133B, 131C, 132C, 133C: Photonic crystal pattern 131h, 132h, 133h: holes 131p, 132p, 133p: Columnar structure 140: color filter layer 150, 150A: light-transmitting conductive pattern 180: light guide plate 180e: light-emitting surface 180i: light incident surface 190: light source 200, 200A: Fingerprint recognition module 200U: Fingerprint recognition unit Da, Db, Dc: pore size EB, EB1, EB2: External light EB1a, EB1b, EB1c: Color Light FG: finger IB, FIB: lighting rays IB’: Fingerprint Image Light IMB: Image Ray PA, PA': Display pixel area Pa, Pb, Pc: pitch RE: Reflective electrode T1, T2: Thickness X, Y, Z: direction

1 is a schematic cross-sectional view of a display device for under-screen recognition according to a first embodiment of the present invention. FIG. 2 is a schematic top view of the photonic crystal layer of FIG. 1 . FIG. 3 is a schematic top view of a photonic crystal layer according to another embodiment of the present invention. 4 is a schematic top view of a photonic crystal layer according to still another embodiment of the present invention. 5 is a schematic cross-sectional view of a display device for under-screen recognition according to a second embodiment of the present invention. 6 is a schematic cross-sectional view of a display device for under-screen recognition according to a third embodiment of the present invention. 7 is a schematic cross-sectional view of a display device for under-screen recognition according to a fourth embodiment of the present invention.

10: Display device recognized under the screen

101: The first substrate

101a: First surface

101b: Second surface

102: Second substrate

105: Active component layer

110: Liquid crystal layer

120: Reflective layer

130: Photonic crystal layer

131, 132, 133: Photonic crystal pattern

140: color filter layer

150: Light-transmitting conductive pattern

200: Fingerprint recognition module

200U: Fingerprint recognition unit

EB, EB1, EB2: External light

FG: finger

IB: Lighting Light

IB’: Fingerprint Image Light

IMB: Image Ray

PA: Display pixel area

RE: Reflective electrode

T1, T2: Thickness

X, Z: direction

Claims (12)

A display device for under-screen recognition, suitable for generating image light under the irradiation of external light, the display device for under-screen recognition comprises: a first substrate; a second substrate disposed opposite to the first substrate; a liquid crystal layer disposed between the first substrate and the second substrate; a reflective layer, disposed between the first substrate and the liquid crystal layer, and used for reflecting a part of the external light to generate the image light; a photonic crystal layer disposed between the first substrate and the liquid crystal layer and not overlapping the reflective layer; and a fingerprint identification module, disposed on the side of the first substrate away from the liquid crystal layer, and overlapping the photonic crystal layer, the fingerprint identification module is suitable for emitting illumination light toward the photonic crystal layer, wherein the photonic crystal layer is suitable for to pass the illumination light and reflect another part of the external light. The display device for under-screen recognition as claimed in claim 1, further comprising an active element layer disposed on the first substrate, and the reflective layer is electrically connected to the active element layer. The display device for under-screen identification according to claim 1, further comprising: a color filter layer overlapping the reflective layer and between the liquid crystal layer and the reflective layer, wherein the photonic crystal layer does not overlap the reflective layer and the color filter layer, and the color filter layer and The thickness of the reflective layer in a stacking direction is equal to the thickness of the photonic crystal layer in the stacking direction. The display device for under-screen recognition according to claim 1, wherein the photonic crystal layer comprises a first photonic crystal pattern, a second photonic crystal pattern and a third photonic crystal pattern suitable for reflecting light of different colors. The display device for under-screen recognition according to claim 4, wherein the first photonic crystal pattern, the second photonic crystal pattern, and the third photonic crystal pattern are respectively used to reflect wavelengths ranging from 630 nm to 750 nm. Red light, green light with wavelengths ranging from 490 nm to 570 nm, and blue light with wavelengths ranging from 440 nm to 470 nm. The display device for under-screen recognition according to claim 4, wherein the orthographic projections of the first photonic crystal pattern, the second photonic crystal pattern and the third photonic crystal pattern on the first substrate do not overlap each other. The display device for under-screen recognition according to claim 4, wherein the orthographic projections of the first photonic crystal pattern, the second photonic crystal pattern and the third photonic crystal pattern on the first substrate overlap with each other. The display device for under-screen identification according to claim 1, further comprising: a light guide plate, disposed on the side of the second substrate away from the liquid crystal layer, and having a light emitting surface facing the reflective layer and a light incident surface connected to the light emitting surface; and A light source is arranged on one side of the light incident surface of the light guide plate. The display device for under-screen recognition according to claim 1, wherein the reflective layer is another photonic crystal layer. The display device for under-screen recognition according to claim 9, wherein the reflective layer and the photonic crystal layer are integrated. The display device for under-screen identification according to claim 1, further comprising: A plurality of light-transmitting conductive patterns are overlapped on the photonic crystal layer, wherein the reflective layer is a plurality of reflective electrodes, and the light-transmitting conductive patterns are respectively electrically connected to the reflective electrodes. The display device for under-screen recognition according to claim 1, wherein the external light is visible light, and the illumination light is infrared light.

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