Detection device

Abstract

Provided is a detection device that comprises a front light and makes it possible to obtain good detection accuracy. The detection device comprises a plurality of photodiodes arrayed on a substrate, a front light, an optical filter layer, and a plurality of lenses. The front light has a light guiding plate disposed overlapping the plurality of photodiodes, a light source for irradiating a first side surface of the light guiding plate with light, and a plurality of scattering sections disposed on the light guiding plate and scattering light from the light source. The optical filter layer has at least one light shielding layer that has a plurality of openings. The plurality of lenses are provided overlapping the plurality of photodiodes in a plan view.

Description

[Technical Field]

[0001] The present disclosure relates to a detection device. [Background technology]

[0002] Optical sensors capable of detecting fingerprint patterns and vein patterns are known (for example, see Patent Documents 1 and 2). In the optical sensors described in Patent Documents 1 and 2, a front light is provided on the front side of a plurality of photodiodes. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-045503 [Patent Document 2] Japanese Patent Application Publication No. 11-120324 Summary of the Invention [Problem to be solved by the invention]

[0004] The contrast of detection may be reduced due to insufficient illuminance of the light emitted from the front light.

[0005] An object of the present disclosure is to provide a detection device that is equipped with a front light and is capable of achieving good detection accuracy. [Means for solving the problem]

[0006] A detection device according to one embodiment of the present disclosure includes a front light having a plurality of photodiodes arranged on a substrate, a light guide plate arranged to overlap the plurality of photodiodes, a light source that irradiates light onto a first side of the light guide plate, and a plurality of scattering sections provided on the light guide plate that scatter light from the light source, an optical filter layer having at least one light-shielding layer having a plurality of openings, and a plurality of lenses arranged to overlap each of the plurality of photodiodes in a planar view. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a perspective view schematically showing a detection device according to a first embodiment. [Figure 2] FIG. 2 is a cross-sectional view showing a schematic cross-sectional configuration of the detection device according to the first embodiment. [Figure 3] FIG. 3 is a plan view showing the detection device according to the first embodiment. [Figure 4] FIG. 4 is a block diagram showing an example of the configuration of the detection device according to the first embodiment. [Figure 5] FIG. 5 is a circuit diagram showing a detection element. [Figure 6] FIG. 6 is a plan view schematically showing the detection element according to the first embodiment. [Figure 7] FIG. 7 is a cross-sectional view taken along line VII-VII' in FIG. [Figure 8] FIG. 8 is a plan view for explaining the arrangement relationship between the photodiode, the optical filter layer, the lens, and the plurality of scattering portions of the front light. [Figure 9] FIG. 9 is a cross-sectional view schematically showing a detection device according to the second embodiment. [Figure 10] FIG. 10 is a plan view showing the arrangement relationship between the lenses and spacers according to the second embodiment. [Figure 11] FIG. 11 is a cross-sectional view showing a schematic cross-sectional configuration of a detection device according to the third embodiment. [Figure 12] FIG. 12 is a cross-sectional view showing a schematic cross-sectional configuration of a detection device according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Modes (embodiments) for carrying out the present disclosure will be described in detail with reference to the drawings. The present disclosure is not limited to the contents described in the following embodiments. Furthermore, the components described below include those that can be easily imagined by a person skilled in the art and those that are substantially identical. Furthermore, the components described below can be combined as appropriate. Note that the disclosure is merely an example, and any appropriate modifications that a person skilled in the art can easily conceive while maintaining the gist of the present disclosure are naturally included within the scope of the present disclosure. Furthermore, for clarity of explanation, the drawings may schematically depict the width, thickness, shape, etc. of each part compared to the actual embodiment. However, these are merely examples and are not intended to limit the interpretation of the present disclosure. Furthermore, in this disclosure and each figure, elements similar to those described above with reference to the previous figures may be designated by the same reference numerals, and detailed descriptions may be omitted as appropriate.

[0009] In this specification and claims, when expressing an aspect of placing another structure on top of a certain structure, the term "on top" is used, unless otherwise specified, to include both a case in which another structure is placed directly on top of a certain structure so as to be in contact with the certain structure, and a case in which another structure is placed above a certain structure via yet another structure.

[0010] (First embodiment) Fig. 1 is a perspective view schematically showing a detection device according to a first embodiment. Fig. 2 is a cross-sectional view showing a schematic cross-sectional configuration of the detection device according to the first embodiment. As shown in Figs. 1 and 2, the detection device 1 includes an optical sensor 5, an optical filter layer 50, and a front light FL. The optical filter layer 50, a lens 56, and the front light FL are stacked in this order on the optical sensor 5.

[0011] The optical sensor 5 has an array substrate 2 and a plurality of detection elements 3 (photodiodes 30) formed on the array substrate 2. The array substrate 2 is formed using a substrate 21 as a base. Each of the plurality of detection elements 3 is configured with a photodiode 30, a plurality of transistors, and various wirings. The array substrate 2 on which the photodiodes 30 are formed is a drive circuit board that drives the sensor for each predetermined detection area, and is also called a backplane or active matrix substrate.

[0012] The optical filter layer 50 is disposed opposite the plurality of photodiodes 30 and is disposed between the plurality of photodiodes 30 and the light guide plate LG of the front light FL and the object to be detected FG, such as a finger. The optical filter layer 50 has a light-transmitting resin 51, a plurality of light guide paths 51R, and light-shielding portions 55A and 55B provided around the plurality of light guide paths 51R. The optical filter layer 50 is formed of, for example, a light-transmitting acrylic resin. At least a portion of the light guide path 51R overlaps the photodiode 30. The light guide path 51R is formed of the same light-transmitting resin as the light-transmitting resin 51.

[0013] The light-shielding portions 55A and 55B have a higher light absorption rate than the light-transmitting resin 51 and the light guide R. The light-shielding portions 55A and 55B are formed of, for example, a black-colored resin material. A second opening 51b is formed in the light-shielding portion 55B, and the second opening 51b overlaps the photodiode 30. The optical filter layer 50 is a light-shielding layer having multiple pinholes formed by the first opening 51a of the light guide 51R and the second opening 51b surrounded by the light-shielding portion 55B. The optical filter layer 50 has a multi-layer pinhole structure in which multiple layers of light-transmitting resin and light-shielding portions are alternately stacked. The optical filter layer 50 is an optical element that transmits a component of light reflected by a detection object FG, such as a finger, traveling in the third direction Dz toward the photodiode 30. The optical filter layer 50 is also called a collimating aperture or a collimator.

[0014] In the following description, the first direction Dx is a direction in a plane parallel to the substrate 21. The second direction Dy is a direction in a plane parallel to the substrate 21, and is a direction perpendicular to the first direction Dx. The second direction Dy may intersect the first direction Dx without being perpendicular thereto. The third direction Dz is a direction perpendicular to the first direction Dx and the second direction Dy, and is a normal direction to the main surface of the substrate 21. Furthermore, "plan view" refers to the positional relationship when viewed from a direction perpendicular to the substrate 21.

[0015] The lens 56 is made of a light-transmitting resin. The lens 56 is a convex lens that is laminated on the optical filter layer 50 and protrudes toward the front light FL. The lens 56 is disposed between the light guide plate LG and the optical filter layer 50. As shown in FIG. 2, the lens 56, the first opening 51a of the light guide path 51R, and the second opening 51b surrounded by the light-shielding portion 55B overlap each other. If the diameter of the lens 56 is D1, the diameter of the first opening 51a of the light guide path 51R is D2, and the diameter of the opening surrounded by the light-shielding portion 55B is D3, then there is a relationship of D1>D2>D3.

[0016] The front light FL is disposed on the optical filter layer 50, i.e., in front of the optical sensor 5 and the optical filter layer 50. The front light FL has a translucent light guide plate LG, a light source LS facing a side surface of the light guide plate LG, and a plurality of scattering portions SC11. Although not shown, the optical filter layer 50 and the front light FL are bonded together with an optical resin. There may be a space (air layer) between the optical filter layer 50 and the front light FL.

[0017] The light source LS is, for example, a light emitting diode (LED) that emits red light or infrared light. The light source LS is not limited to this and can be changed appropriately to a color such as green depending on the measurement item. A plurality of LEDs of the light source LS are arranged along the side surface of the light guide plate LG.

[0018] The object to be detected FG is disposed facing the detection surface SF of the light guide plate LG. The scattering portions SC11 are provided on the surface of the light guide plate LG opposite the detection surface SF, i.e., on the surface of the light guide plate LG facing the optical filter layer 50. The scattering portions SC11 are provided in areas overlapping with the light-shielding portions 55A of the optical filter layer 50. The scattering portions SC11 have a triangular prism shape. The scattering portions SC11 may be dot-shaped recesses or protrusions, or grooves.

[0019] Light emitted from the light source LS propagates through the light guide plate LG while repeatedly being totally reflected at the detection surface SF and the back surface. A portion of the light propagating through the light guide plate LG is scattered by the scattering section SC11. A portion of the light scattered by the scattering section SC11 is emitted from the detection surface SF of the light guide plate LG to the object to be detected FG. A portion of the light reflected by the object to be detected FG passes through the light guide plate LG and the light guide path 51R of the optical filter layer 50 and is irradiated onto the multiple photodiodes 30. As a result, the multiple photodiodes 30 of the optical sensor 5 can detect information about the object to be detected FG using the light irradiated from the light source LS.

[0020] Furthermore, the light scattered by the scattering section SC11 includes a component that is emitted toward the detected object FG side as well as a component that is emitted toward the optical filter layer 50 facing the light guide plate LG. Since the scattering section SC11 is provided in a region that overlaps with the light-shielding section 55A of the optical filter layer 50, the light scattered by the scattering section SC11 toward the optical filter layer 50 does not enter the light guide path 51R, but is blocked by the light-shielding section 55A.

[0021] As a result, in the detection device 1, the photodiodes 30 of the optical sensor 5 are mainly irradiated with light reflected by the object to be detected FG, and the amount of light emitted from the front light FL that directly enters the photodiodes 30 on the side opposite to the object to be detected FG is suppressed. Therefore, the detection device 1 having the front light FL can improve detection accuracy.

[0022] The object to be detected FG may be, for example, a finger, a palm, or a wrist. For example, the optical sensor 5 may detect information such as a fingerprint of the object to be detected FG based on light. The optical sensor 5 may also detect various types of information (biometric information), such as the shape of blood vessels, pulse, and pulse wave. That is, the detection device 1 may be configured as a fingerprint detection device that detects fingerprints, or a vein detection device that detects blood vessel patterns such as veins. The light source LS of the front light FL is not limited to one type, and multiple types having different wavelengths may be provided.

[0023] 3 is a plan view showing the detection device according to the first embodiment. As shown in Fig. 3, the optical sensor 5 of the detection device 1 has a substrate 21 (array substrate 2), a sensor unit 10, a scanning line driving circuit 15, a signal line selection circuit 16, a detection circuit 48, a control circuit 102, and a power supply circuit 103.

[0024] A control board 501 is electrically connected to the substrate 21 via a wiring board 510. The wiring board 510 is, for example, a flexible printed circuit board or a rigid board. The wiring board 510 is provided with a detection circuit 48. The control board 501 is provided with a control circuit 102 and a power supply circuit 103. The control circuit 102 is, for example, an FPGA (Field Programmable Gate Array). The control circuit 102 supplies control signals to the sensor unit 10, the scanning line driving circuit 15, and the signal line selection circuit 16 to control the detection operation of the sensor unit 10. The control circuit 102 also supplies a control signal to the front light FL (see FIGS. 1 and 2) to control the lighting or non-lighting of the light source 123. The power supply circuit 103 supplies voltage signals such as a power supply potential SVS and a reference potential VR1 (see FIG. 5) to the sensor unit 10, the scanning line driving circuit 15, and the signal line selection circuit 16.

[0025] The substrate 21 has a detection area AA and a peripheral area GA. The detection area AA is an area where a plurality of photodiodes 30 of the sensor unit 10 are provided. The peripheral area GA is an area between the outer periphery of the detection area AA and the edge of the substrate 21, where a plurality of photodiodes 30 are not provided.

[0026] The scanning line driving circuit 15 and the signal line selection circuit 16 are provided in the peripheral area GA. Specifically, the scanning line driving circuit 15 is provided in a region of the peripheral area GA extending along the second direction Dy. The signal line selection circuit 16 is provided in a region of the peripheral area GA extending along the first direction Dx, and is provided between the sensor unit 10 and the detection circuit 48.

[0027] Each of the plurality of detection elements 3 of the sensor unit 10 is an optical sensor having a photodiode 30 as a sensor element. The photodiode 30 is a photoelectric conversion element that outputs an electrical signal according to the light irradiated thereon. More specifically, the photodiode 30 is a PIN (Positive Intrinsic Negative) photodiode or an OPD (Organic Photodiode) using an organic semiconductor. The plurality of detection elements 3 (photodiodes 30) are arranged in a matrix in the detection area AA.

[0028] The photodiodes 30 included in the multiple detection elements 3 perform detection in accordance with gate drive signals supplied from the scanning line drive circuit 15. The multiple photodiodes 30 output electrical signals corresponding to the light irradiated thereon as detection signals Vdet to the signal line selection circuit 16. The detection device 1 detects information related to the object to be detected Fg based on the detection signals Vdet from the multiple photodiodes 30.

[0029] Fig. 4 is a block diagram showing an example of the configuration of the detection device according to the first embodiment. As shown in Fig. 4, the detection device 1 further includes a detection control circuit 11 and a detection unit 40. Some or all of the functions of the detection control circuit 11 are included in a control circuit 102. In addition, some or all of the functions of the detection unit 40 other than the detection circuit 48 are included in the control circuit 102.

[0030] The detection control circuit 11 is a circuit that supplies control signals to the scanning line driving circuit 15, the signal line selection circuit 16, and the detection unit 40, respectively, and controls their operations. The detection control circuit 11 supplies various control signals, such as a start signal STV, a clock signal CK, and a reset signal RST1, to the scanning line driving circuit 15. The detection control circuit 11 also supplies various control signals, such as a selection signal ASW, to the signal line selection circuit 16.

[0031] The scanning line driving circuit 15 is a circuit that drives multiple scanning lines GLS (see FIG. 5) based on various control signals. The scanning line driving circuit 15 selects multiple scanning lines GLS sequentially or simultaneously, and supplies a gate driving signal VGL to the selected scanning lines GLS. In this way, the scanning line driving circuit 15 selects multiple photodiodes 30 connected to the scanning lines GLS.

[0032] The signal line selection circuit 16 is a switch circuit that sequentially or simultaneously selects a plurality of output signal lines SLS (see FIG. 5 ). The signal line selection circuit 16 is, for example, a multiplexer. The signal line selection circuit 16 connects the selected output signal line SLS to the detection circuit 48 based on a selection signal ASW supplied from the detection control circuit 11. As a result, the signal line selection circuit 16 outputs the detection signal Vdet of the photodiode 30 to the detection unit 40.

[0033] The detection unit 40 includes a detection circuit 48, a signal processing circuit 44, a coordinate extraction circuit 45, a memory circuit 46, and a detection timing control circuit 47. Based on a control signal supplied from the detection control circuit 11, the detection timing control circuit 47 controls the detection circuit 48, the signal processing circuit 44, and the coordinate extraction circuit 45 so that they operate in synchronization.

[0034] The detection circuit 48 is, for example, an analog front end (AFE) circuit. The detection circuit 48 is a signal processing circuit having at least the functions of a detection signal amplifier circuit 42 and an A / D conversion circuit 43. The detection signal amplifier circuit 42 amplifies the detection signal Vdet. The A / D conversion circuit 43 converts the analog signal output from the detection signal amplifier circuit 42 into a digital signal.

[0035] The signal processing circuit 44 is a logic circuit that detects a predetermined physical quantity input to the sensor unit 10 based on the output signal of the detection circuit 48. When a finger comes into contact with or close to the detection surface SF (light guide plate LG), the signal processing circuit 44 can detect unevenness on the surface of the finger or palm based on the signal from the detection circuit 48. The signal processing circuit 44 can also detect information about the living body based on the signal from the detection circuit 48. The information about the living body includes, for example, an image of the blood vessels of the finger or palm, a pulse wave, a pulse rate, and a blood oxygen concentration.

[0036] The memory circuit 46 temporarily stores the signals calculated by the signal processing circuit 44. The memory circuit 46 may be, for example, a RAM (Random Access Memory), a register circuit, or the like.

[0037] The coordinate extraction circuit 45 is a logic circuit that calculates the detected coordinates of the unevenness of the surface of a finger or the like when the signal processing circuit 44 detects contact or proximity of a finger. The coordinate extraction circuit 45 is also a logic circuit that calculates the detected coordinates of the blood vessels of the finger or palm. The coordinate extraction circuit 45 combines the detection signals Vdet output from each photodiode 30 of the sensor unit 10 to generate two-dimensional information indicating the shape of the unevenness of the surface of the finger or the like and two-dimensional information indicating the shape of the blood vessels of the finger or palm. The coordinate extraction circuit 45 may output the detection signal Vdet as the sensor output voltage Vo without calculating the detection coordinates.

[0038] Next, an example of the circuit configuration of the optical sensor 5 will be described. FIG. 5 is a circuit diagram showing a detection element. As shown in FIG. 5, the detection element 3 includes a photodiode 30, a capacitance element Ca, and a first transistor Tr. The first transistor Tr is provided corresponding to the photodiode 30. The first transistor Tr is configured by a thin film transistor, and in this example, is configured by an n-channel MOS (Metal Oxide Semiconductor) TFT (Thin Film Transistor). The gate of the first transistor Tr is connected to the scanning line GLS. The source of the first transistor Tr is connected to the output signal line SLS. The drain of the first transistor Tr is connected to the anode of the photodiode 30 and the capacitance element Ca.

[0039] A power supply potential SVS is supplied to the cathode of the photodiode 30 from the power supply circuit 103. Furthermore, a reference potential VR1, which is the initial potential of the capacitance element Ca, is supplied from the power supply circuit 103 to the capacitance element Ca.

[0040] When light is irradiated onto the detection element 3, a current corresponding to the amount of light flows through the photodiode 30, causing charge to accumulate in the capacitance element Ca. When the first transistor Tr is turned on, a current corresponding to the charge accumulated in the capacitance element Ca flows through the output signal line SLS. The output signal line SLS is connected to the detection circuit 48 via the signal line selection circuit 16. This allows the detection device 1 to detect a signal corresponding to the amount of light irradiated onto the photodiode 30 for each detection element 3.

[0041] 5 shows one detection element 3, the scanning line GLS and the output signal line SLS are connected to a plurality of detection elements 3. Specifically, the scanning line GLS extends in a first direction Dx (see FIG. 3) and is connected to a plurality of detection elements 3 arranged in the first direction Dx. Furthermore, the output signal line SLS extends in a second direction Dy and is connected to a plurality of detection elements 3 arranged in the second direction Dy.

[0042] The first transistor Tr is not limited to an n-type TFT, and may be a p-type TFT. In addition, in the detection element 3, a plurality of transistors may be provided corresponding to one photodiode 30.

[0043] Next, the detailed configuration of the detection device 1 will be described. FIG. 6 is a plan view schematically showing a detection element according to the first embodiment. As shown in FIG. 6, the detection element 3 is an area surrounded by the scanning lines GLS and the output signal lines SLS. In this embodiment, the scanning lines GLS include a first scanning line GLA and a second scanning line GLB. The first scanning line GLA is provided so as to overlap with the second scanning line GLB. The first scanning line GLA and the second scanning line GLB are provided in different layers with insulating layers 22c and 22d (see FIG. 7) interposed therebetween. The first scanning line GLA and the second scanning line GLB are electrically connected at an arbitrary position and are supplied with a gate drive signal VGL having the same potential. At least one of the first scanning line GLA and the second scanning line GLB is connected to a scanning line drive circuit 15. Although the first scanning line GLA and the second scanning line GLB have different widths in FIG. 6, they may have the same width.

[0044] The photodiodes 30 are provided in an area surrounded by the scanning lines GLS and the output signal lines SLS. An upper electrode 34 and a lower electrode 35 are provided corresponding to each photodiode 30. The photodiodes 30 are, for example, PIN photodiodes. The lower electrode 35 is, for example, an anode electrode of the photodiode 30. The upper electrode 34 is, for example, a cathode electrode of the photodiode 30.

[0045] The upper electrode 34 is connected to the power supply signal line Lvs via a connection wiring 36. The power supply signal line Lvs is a wiring that supplies a power supply potential SVS to the photodiode 30. In this embodiment, the power supply signal line Lvs extends in the second direction Dy, overlapping with the output signal line SLS. The multiple detection elements 3 arranged in the second direction Dy are connected to a common power supply signal line Lvs. This configuration allows the aperture of the detection element 3 to be large. The lower electrode 35, the photodiode 30, and the upper electrode 34 are each substantially rectangular in plan view. However, this is not limited thereto, and the shapes of the lower electrode 35, the photodiode 30, and the upper electrode 34 can be changed as appropriate.

[0046] The first transistor Tr is provided near the intersection of the scanning line GLS and the output signal line SLS, and includes a semiconductor layer 61, a source electrode 62, a drain electrode 63, a first gate electrode 64A, and a second gate electrode 64B.

[0047] The semiconductor layer 61 is an oxide semiconductor. More preferably, the semiconductor layer 61 is a transparent amorphous oxide semiconductor (TAOS) among oxide semiconductors. By using an oxide semiconductor for the first transistor Tr, the leakage current of the first transistor Tr can be suppressed. That is, the first transistor Tr can reduce the leakage current from the unselected detection elements 3. This allows the detection device 1 to improve the S / N ratio. However, the semiconductor layer 61 is not limited to this, and may be a microcrystalline oxide semiconductor, an amorphous oxide semiconductor, polysilicon, low temperature polycrystalline silicon (LTPS), etc.

[0048] The semiconductor layer 61 is provided along the first direction Dx and intersects with the first gate electrode 64A and the second gate electrode 64B in a plan view. The first gate electrode 64A and the second gate electrode 64B are provided branching off from the first scanning line GLA and the second scanning line GLB, respectively. In other words, portions of the first scanning line GLA and the second scanning line GLB that overlap with the semiconductor layer 61 function as the first gate electrode 64A and the second gate electrode 64B. The first gate electrode 64A and the second gate electrode 64B are made of aluminum (Al), copper (Cu), silver (Ag), molybdenum (Mo), or an alloy thereof. In addition, a channel region is formed in the portion of the semiconductor layer 61 that overlaps with the first gate electrode 64A and the second gate electrode 64B.

[0049] One end of the semiconductor layer 61 is connected to a source electrode 62 via a contact hole H1. The other end of the semiconductor layer 61 is connected to a drain electrode 63 via a contact hole H2. A portion of the output signal line SLS that overlaps with the semiconductor layer 61 serves as the source electrode 62. A portion of the third conductive layer 67 that overlaps with the semiconductor layer 61 functions as the drain electrode 63. The third conductive layer 67 is connected to the lower electrode 35 via a contact hole H3. With this configuration, the first transistor Tr can switch between connecting and disconnecting the photodiode 30 and the output signal line SLS.

[0050] The arrangement pitch of the detection elements 3 (photodiodes 30) in the first direction Dx is determined by the arrangement pitch of the output signal lines SLS in the first direction Dx. The arrangement pitch of the detection elements 3 (photodiodes 30) in the second direction Dy is determined by the arrangement pitch of the scanning lines GLS in the second direction Dy.

[0051] Next, the layer structure of the optical sensor 5 will be described. FIG. 7 is a cross-sectional view taken along line VII-VII' in FIG. 6. In FIG. 7, in order to show the relationship between the layer structure of the detection area AA (see FIG. 3) and the layer structure of the peripheral area GA (see FIG. 3), a cross section along line VII-VII' and a cross section of a portion of the peripheral area GA including the second transistor TrG are shown connected together. Furthermore, FIG. 7 also shows a cross section of a portion of the peripheral area GA including the terminal portion 72 connected together.

[0052] In the description of the optical sensor 5, in the direction perpendicular to the surface of the substrate 21 (third direction Dz), the direction from the substrate 21 toward the photodiode 30 will be referred to as the "upper side" or "top." The direction from the photodiode 30 toward the substrate 21 will be referred to as the "lower side" or "bottom."

[0053] 7, the substrate 21 is an insulating substrate, and may be, for example, a glass substrate such as quartz or alkali-free glass. On one surface of the substrate 21, a first transistor Tr, various wirings (scanning lines GLS and output signal lines SLS), and an insulating layer are provided to form an array substrate 2. The photodiodes 30 are arranged on the array substrate 2, i.e., on one surface of the substrate 21. The substrate 21 may be a resin substrate or a resin film made of a resin such as polyimide.

[0054] The insulating layers 22a and 22b are provided on the substrate 21. The insulating layers 22a, 22b, 22c, 22d, 22e, 22f, and 22g are inorganic insulating films, such as silicon oxide (SiO2), silicon nitride (SiN), etc. Furthermore, each inorganic insulating layer is not limited to a single layer and may be a multilayer film.

[0055] The first gate electrode 64A is provided on the insulating layer 22b. The insulating layer 22c is provided on the insulating layer 22b, covering the first gate electrode 64A. The semiconductor layer 61, the first conductive layer 65, and the second conductive layer 66 are provided on the insulating layer 22c. The first conductive layer 65 is provided to cover the end of the semiconductor layer 61 that is connected to the source electrode 62. The second conductive layer 66 is provided to cover the end of the semiconductor layer 61 that is connected to the drain electrode 63.

[0056] The insulating layer 22d is provided on the insulating layer 22c, covering the semiconductor layer 61, the first conductive layer 65, and the second conductive layer 66. The second gate electrode 64B is provided on the insulating layer 22d. The semiconductor layer 61 is provided between the first gate electrode 64A and the second gate electrode 64B in the direction perpendicular to the substrate 21. In other words, the first transistor Tr has a so-called dual-gate structure. However, the first transistor Tr may have a bottom-gate structure in which the first gate electrode 64A is provided but the second gate electrode 64B is not provided, or a top-gate structure in which the first gate electrode 64A is not provided but only the second gate electrode 64B is provided.

[0057] The insulating layer 22e is provided on the insulating layer 22d, covering the second gate electrode 64B. The source electrode 62 (output signal line SLS) and the drain electrode 63 (third conductive layer 67) are provided on the insulating layer 22e. In this embodiment, the drain electrode 63 is the third conductive layer 67 provided on the semiconductor layer 61 via the insulating layers 22d and 22e. The source electrode 62 is electrically connected to the semiconductor layer 61 via a contact hole H1 and a first conductive layer 65. The drain electrode 63 is electrically connected to the semiconductor layer 61 via a contact hole H2 and a second conductive layer 66.

[0058] The third conductive layer 67 is provided in a region overlapping with the photodiode 30 in plan view. The third conductive layer 67 is also provided above the semiconductor layer 61, the first gate electrode 64A, and the second gate electrode 64B. That is, the third conductive layer 67 is provided between the second gate electrode 64B and the lower electrode 35 in the direction perpendicular to the substrate 21. As a result, the third conductive layer 67 functions as a protective layer that protects the first transistor Tr.

[0059] The second conductive layer 66 extends opposite the third conductive layer 67 in a region not overlapping with the semiconductor layer 61. Furthermore, a fourth conductive layer 68 is provided on the insulating layer 22d in a region not overlapping with the semiconductor layer 61. The fourth conductive layer 68 is provided between the second conductive layer 66 and the third conductive layer 67. As a result, a capacitance is formed between the second conductive layer 66 and the fourth conductive layer 68, and a capacitance is formed between the third conductive layer 67 and the fourth conductive layer 68. The capacitance formed by the second conductive layer 66, the third conductive layer 67, and the fourth conductive layer 68 is the capacitance of the capacitive element Ca shown in FIG. 5 .

[0060] The first organic insulating layer 23a is provided on the insulating layer 22e, covering the source electrode 62 (output signal line SLS) and the drain electrode 63 (third conductive layer 67). The first organic insulating layer 23a is a planarizing layer that flattens unevenness formed by the first transistor Tr and various conductive layers.

[0061] Next, a description will be given of the cross-sectional structure of the photodiode 30. The photodiode 30 is formed by stacking a lower electrode 35, the photodiode 30, and an upper electrode 34 on the first organic insulating layer 23a of the array substrate 2 in this order.

[0062] The lower electrode 35 is provided on the first organic insulating layer 23a and is electrically connected to the third conductive layer 67 through a contact hole H3. The lower electrode 35 is the anode of the photodiode 30 and is an electrode for reading out the detection signal Vdet. The lower electrode 35 is made of a metal material such as molybdenum (Mo) or aluminum (Al). Alternatively, the lower electrode 35 may be a laminated film in which a plurality of these metal materials are laminated. The lower electrode 35 may also be made of a light-transmitting conductive material such as ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide).

[0063] The photodiode 30 includes semiconductor layers such as an i-type semiconductor layer 31, an n-type semiconductor layer 32, and a p-type semiconductor layer 33. The i-type semiconductor layer 31, the n-type semiconductor layer 32, and the p-type semiconductor layer 33 are formed of, for example, amorphous silicon (a-Si). In FIG. 7, the p-type semiconductor layer 33, the i-type semiconductor layer 31, and the n-type semiconductor layer 32 are stacked in this order in the direction perpendicular to the surface of the substrate 21. However, the opposite configuration, that is, the n-type semiconductor layer 32, the i-type semiconductor layer 31, and the p-type semiconductor layer 33 may also be used. Each semiconductor layer may be a photoelectric conversion element made of an organic semiconductor.

[0064] The n-type semiconductor layer 32 is formed by doping impurities into a-Si to form an n+ region. The p-type semiconductor layer 33 is formed by doping impurities into a-Si to form a p+ region. The i-type semiconductor layer 31 is, for example, an undoped intrinsic semiconductor and has lower conductivity than the n-type semiconductor layer 32 and the p-type semiconductor layer 33.

[0065] The upper electrode 34 is a cathode of the photodiode 30 and is an electrode for supplying the power supply potential SVS to the photoelectric conversion layer. The upper electrode 34 is a light-transmitting conductive layer made of, for example, ITO, and a plurality of upper electrodes 34 are provided for each photodiode 30.

[0066] Insulating layers 22f and 22g are provided on the first organic insulating layer 23a. Insulating layer 22f covers the periphery of the upper electrode 34, and an opening is provided in the insulating layer 22f at a position where it overlaps with the upper electrode 34. The connecting wiring 36 is connected to the upper electrode 34 at a portion of the upper electrode 34 where insulating layer 22f is not provided. Insulating layer 22g is provided on insulating layer 22f, covering the upper electrode 34 and the connecting wiring 36. A second organic insulating layer 23b, which is a planarizing layer, is provided on insulating layer 22g. In the case of an organic semiconductor photodiode 30, an insulating layer 22h may be further provided thereon.

[0067] The peripheral area GA is provided with a second transistor TrG of the scanning line driving circuit 15. The second transistor TrG is provided on the same substrate 21 as the first transistor Tr. The second transistor TrG includes a semiconductor layer 81, a source electrode 82, a drain electrode 83, and a gate electrode 84.

[0068] The semiconductor layer 81 is made of polysilicon. More preferably, the semiconductor layer 81 is made of low-temperature polysilicon (LTPS). The semiconductor layer 81 is provided on the insulating layer 22a. That is, the semiconductor layer 61 of the first transistor Tr is provided at a position farther from the substrate 21 than the semiconductor layer 81 of the second transistor TrG in a direction perpendicular to the substrate 21. However, without being limited thereto, the semiconductor layer 81 may be formed in the same layer and from the same material as the semiconductor layer 61.

[0069] The gate electrode 84 is provided above the semiconductor layer 81 with an insulating layer 22b interposed therebetween. The gate electrode 84 is provided in the same layer as the first gate electrode 64A. The second transistor TrG has a so-called top-gate structure. However, the second transistor TrG may have a dual-gate structure or a bottom-gate structure.

[0070] The source electrode 82 and the drain electrode 83 are provided on the insulating layer 22e. The source electrode 82 and the drain electrode 83 are provided in the same layer as the source electrode 62 and the drain electrode 63 of the first transistor Tr. Contact holes H4 and H5 are provided from the insulating layer 22b through the insulating layer 22e. The source electrode 82 is electrically connected to the semiconductor layer 81 via the contact hole H4. The drain electrode 83 is electrically connected to the semiconductor layer 81 via the contact hole H5.

[0071] The terminal portion 72 is provided in a position in the peripheral area GA that is different from the area in which the scanning line driving circuit 15 is provided. The terminal portion 72 has a first terminal conductive layer 73, a second terminal conductive layer 74, a third terminal conductive layer 75, and a fourth terminal conductive layer 76. The first terminal conductive layer 73 is provided on the insulating layer 22b, in the same layer as the first gate electrode 64A. A contact hole H6 is provided to communicate between the insulating layers 22c, 22d, and 22e and the first organic insulating layer 23a.

[0072] The second terminal conductive layer 74, the third terminal conductive layer 75, and the fourth terminal conductive layer 76 are stacked in this order within the contact hole H6 and are electrically connected to the first terminal conductive layer 73. The second terminal conductive layer 74 can be formed using the same material and in the same process as the third conductive layer 67, etc. The third terminal conductive layer 75 can be formed using the same material and in the same process as the lower electrode 35. The fourth terminal conductive layer 76 can be formed using the same material and in the same process as the connection wiring 36 and the power signal line Lvs (see FIG. 6).

[0073] 7 shows one terminal portion 72, but a plurality of terminal portions 72 are arranged at intervals. The plurality of terminal portions 72 are electrically connected to the wiring board 510 (see FIG. 2) by, for example, anisotropic conductive film (ACF) or the like.

[0074] The optical sensor 5 is not limited to the above-described structure as long as it can detect light with the photodiode 30. Furthermore, the optical sensor 5 may be one that detects information other than fingerprint information, as long as it receives light with the photodiode 30 and detects information.

[0075] 8 is a plan view illustrating the positional relationship between the photodiode, the optical filter layer, the lens, and the multiple scattering portions of the frontlight. In FIG. 8, the light-shielding portion 55A of the optical filter layer is indicated by hatching. The photodiode 30 is also schematically indicated by dotted lines. The outer shape of the photodiode 30 is, for example, the outer shape of the n-type semiconductor layer 32 (see FIG. 7) that constitutes the light-receiving portion of the photodiode 30. The scattering portion SC11 of the frontlight FL is also indicated by hatching to distinguish it from the light-shielding portion 55A.

[0076] As shown in Fig. 8, the plurality of light guide paths 51R of the optical filter layer 50 are arranged in a matrix in the first direction Dx and the second direction Dy. Each of the plurality of light guide paths 51R is capable of transmitting light. As shown in Figs. 8 and 2, each of the plurality of light guide paths 51R has a first opening 51a on the front light FL side. In this embodiment, the plurality of light guide paths 51R extend in the third direction Dz, and the second openings 51b are arranged to overlap the first openings 51a in a plan view. Furthermore, the first openings 51a have a larger area than the second openings 51b.

[0077] The light absorptance of the light shielding portion 55A is higher than that of the plurality of light guide paths 51R. In other words, the light transmittance of the plurality of light guide paths 51R is higher than that of the light shielding portion 55A. The light shielding portion 55A is provided around the plurality of light guide paths 51R and is made of a material that does not easily transmit light. The light absorptance of the light shielding portion 55A is preferably 99% or more and 100% or less, and more preferably 100%. Here, the light absorptance refers to the ratio ((Lin-Lout) / Lin) of the difference between the intensity of incident light Lin and the intensity of output light Lout to the intensity of incident light in.

[0078] 2, the first openings 51a and second openings 51b of the plurality of light guides 51R are arranged so as to overlap the photodiodes 30. As shown in FIG. 8, four lenses 56 each overlap one first opening 51a. Four light guides 51R are provided so as to overlap one photodiode 30. However, this is not limiting, and it is sufficient that at least one light guide 51R is provided so as to overlap one photodiode 30.

[0079] In a plan view, the scattering portions SC11 are arranged in a matrix on the light guide plate LG of the front light FL. The diameter of the scattering portions SC11 is smaller than the diameter of the light guide path 51R. As described above, the scattering portions SC11 of the front light FL are provided in regions that overlap with the light blocking portions 55A of the optical filter layer 50. In other words, the scattering portions SC11 of the front light FL are provided in regions that do not overlap with the light guide path 51R of the optical filter layer 50.

[0080] The scattering portions SC11 are arranged at a lower density in the region overlapping with the plurality of light guides 51R than in the region overlapping with the light blocking portion 55A. The convex portions of the scattering portions SC11 are provided in the region not overlapping with the lenses 56.

[0081] 8, the number and diameter of the scattering portions SC11 are shown schematically for ease of viewing, but the number, diameter, arrangement pitch, and arrangement density of the scattering portions SC11 can be changed as appropriate. Furthermore, the scattering portions SC11 are not limited to a configuration in which they do not overlap with all of the light guide paths 51R of the optical filter layer 50, and may be provided so as to overlap with some of the light guide paths 51R.

[0082] 2 and 8, in this embodiment, the scattering portion SC11 of the front light FL is provided in an area overlapping with the light-shielding portion 55A of the optical filter layer 50, and is provided so as not to overlap with the light guide path 51R. The area of ​​the light guide plate LG of the front light FL that overlaps with the light guide path 51R is formed as a flat surface on which the scattering portion SC11 is not formed. As a result, light scattered upward (toward the object FG) by the scattering portion SC11 is reflected by the object FG such as a finger, passes through the light guide path 51R, and enters the photodiode 30.

[0083] On the other hand, light scattered by the scattering portions SC11 toward the optical filter layer 50 does not enter the light guide path 51R but is blocked by the light-shielding portions 55A. Furthermore, no scattering portions SC11 are provided in the region overlapping with the light guide path 51R, or the number of scattering portions SC11 overlapping with the light guide path 51R is smaller than that of the light-shielding portions 55A. Therefore, light traveling inside the light guide plate LG is totally reflected in the region overlapping with the light guide path 51R, thereby suppressing light from the light guide plate LG of the front light FL from directly entering the light guide path 51R. In other words, the detection device 1 can suppress external light other than light reflected by the object FG from entering the photodiode 30. As a result, noise in the photodiode 30 is reduced, and the sensing sensitivity of the detection device 1 is improved.

[0084] The configuration of the optical filter layer 50 can be changed as appropriate. For example, the light guide 51R is not limited to a configuration extending in the third direction Dz, but may be provided at an angle with respect to the third direction Dz. Furthermore, the second opening 51b and the first opening 51a are not limited to a configuration having the same area, but may have different areas.

[0085] As described above, the detection device 1 of the first embodiment includes a plurality of photodiodes 30 arranged on the array substrate 2, a front light FL, an optical filter layer 50, and a plurality of lenses 56. The front light FL includes a light guide plate LG arranged to overlap the plurality of photodiodes 30, a light source of the front light FL that irradiates a first side surface of the light guide plate LG, and a plurality of scattering portions SC11 provided on the light guide plate LG that scatter light from the light source of the front light FL. The optical filter layer 50 includes at least a light-shielding portion 55B having a plurality of second openings 51b. The plurality of lenses 56 are provided to overlap each of the plurality of photodiodes 30 in a plan view.

[0086] The front light FL may have insufficient illumination. In the detection device 1 of the first embodiment, the lens 56 collects light reflected by the detection object FG such as a finger. Therefore, the detection device 1 of the first embodiment can improve the utilization efficiency of the light reflected by the detection object FG and obtain good detection accuracy.

[0087] (Second embodiment) Fig. 9 is a cross-sectional view schematically showing a detection device according to a second embodiment. Fig. 10 is a plan view showing the arrangement of lenses and spacers according to the second embodiment. In the following description, the same components as those described in the above-mentioned embodiments are designated by the same reference numerals, and redundant description will be omitted.

[0088] As shown in FIGS. 9 and 10 , the detection device 1A of the second embodiment includes a plurality of spacers 59 that regulate the distance between the light guide plate LG and the optical filter layer 50. The spacers 59 are made of a light-transmitting resin. The spacers 59 are cylindrical. An air layer is present between the light guide plate LG and the optical filter layer 50.

[0089] It is desirable that the surface shape of the lens 56 is scratch-resistant, as this may affect the detection accuracy of the photodiode 30. The spacer 59 ensures a distance between the lens 56 and the light guide plate LG, and prevents the occurrence of surface shape abnormalities such as scratches on the surface of the lens 56.

[0090] 10, in the second embodiment, the lenses 56 are arranged so that connecting the centers of three adjacent lenses forms a triangle. The spacers 59 are provided in areas that do not overlap with the lenses 56. This makes it less likely that the spacers 59 will affect the light collection of the lenses 56.

[0091] (Third embodiment) 11 is a cross-sectional view showing a schematic cross-sectional configuration of a detection device according to the third embodiment. In the following description, the same components as those described in the above embodiments are denoted by the same reference numerals, and redundant description will be omitted. In the detection device 1B of the third embodiment, the position of the lens 56 is different.

[0092] The lens 56 in the third embodiment is disposed on the detection surface SF of the light guide plate LG, which is on the opposite side to the optical filter layer 50. The lens 56 is closer to the object to be detected FG than in the first embodiment. This allows the detection device 1B of the third embodiment to improve the light utilization efficiency.

[0093] In the third embodiment, the optical filter layer 50, the front light FL, and the lens 56 are stacked in this order on the optical sensor 5. The light-shielding portion 55A is provided on the surface facing the front light FL, and the air layer 57 acts like a second lens. Therefore, in this embodiment, the scattering portion SC11 is provided in an area overlapping the light-shielding portion 55A, but not in an area overlapping the light guide path 51R. A flat surface is formed between the scattering portions SC11, and this flat surface is provided in an area overlapping the light guide path 51R. In the third embodiment, the detection device 1B has a support layer 58 in the peripheral area GA (see FIG. 3) that regulates the distance between the light guide plate LG and the optical filter layer 50. The support layer 58 is, for example, an adhesive resin. The support layer 58 prevents the scattering portion SC11 from contacting the optical filter layer 50.

[0094] The scattering portions SC11 are multiple convex portions that protrude toward the optical filter layer 50 side of the light guide plate LG. These convex portions have a triangular prism shape. If the convex portions of the scattering portions SC11 are provided in an area that does not overlap with the lens 56 in a plan view, light that passes from the convex portions through the area that does not overlap with the lens 56 irradiates the object FG to be detected. This makes it possible to prevent the lens 56 from causing partial non-uniformity in the irradiated light.

[0095] (Fourth embodiment) 12 is a cross-sectional view showing a schematic cross-sectional configuration of a detection device according to the fourth embodiment. In the following description, the same components as those described in the above embodiments are denoted by the same reference numerals, and redundant description will be omitted. The detection device 1C of the fourth embodiment includes a scattering unit SC12 that is different from that of the third embodiment.

[0096] The scattering portion SC12 is a plurality of convex portions that protrude toward the optical filter layer 50 side of the light guide plate LG. These convex portions have a hemispherical shape. The scattering portion SC12 is covered with a reflective layer 55C made of a metal with metallic luster, such as Al or an Al alloy. As a result, the scattering portion SC12 and the reflective layer 55C form a concave mirror.

[0097] 12, when the convex portion of the scattering unit SC12 is provided in an area that does not overlap with the lens 56 in a plan view, the light that passes through the area that does not overlap with the lens 56 from the concave mirror irradiates the object FG. This makes it possible to prevent the irradiated light from becoming partially non-uniform due to the lens 56.

[0098] Furthermore, in the detection device 1B, the air layer 57 has support layers 58A that regulate the distance between the light guide plate LG and the optical filter layer 50. In the third embodiment, the support layers 58A are provided interspersed between the reflective layer 55C and the optical filter layer 50. Since a large number of support layers 58A are arranged in the plane, the distance between the light guide plate LG and the optical filter layer 50 is made uniform in the plane.

[0099] Furthermore, since the reflective layer 55C is provided, the light-shielding portion 55A is omitted in the fourth embodiment. Note that, like the third embodiment, the detection device 1C may include the light-shielding portion 55A.

[0100] Although preferred embodiments of the present disclosure have been described above, the present disclosure is not limited to such embodiments. The contents disclosed in the embodiments are merely examples, and various modifications are possible within the scope of the present disclosure. Appropriate modifications made within the scope of the present disclosure naturally fall within the technical scope of the present disclosure. At least one of various omissions, substitutions, and modifications of components can be made within the scope of the gist of each of the above-described embodiments and modifications. [Explanation of symbols]

[0101] 1, 1A, 1B, 1C Detector 2 Array board 3. Detector element 5 Optical Sensor 10 Sensor section 11 Detection control circuit 15 Scanning line driving circuit 16 Signal line selection circuit 21 PCB 30 Photodiode 50 optical filter layer 51 Translucent resin 51R light guide path 55A, 55B Light shielding part 56 Lens 57 Air Layer 58, 58A support layer 59 Spacer AA detection area GA peripheral area FL Front Light LG light guide plate SC11, SC12 scattering part

Claims

1. a plurality of photodiodes arranged on a substrate; a front light including a light guide plate disposed to overlap the plurality of photodiodes, a light source that irradiates light onto a first side surface of the light guide plate, and a plurality of scattering portions that are provided on the light guide plate and that scatter the light from the light source; an optical filter layer having at least one light blocking layer with a plurality of openings; a plurality of lenses provided so as to overlap the plurality of photodiodes, respectively, in a plan view; a spacer that regulates the distance between the light guide plate and the optical filter layer; the spacers are provided in areas around the lenses in a plan view but not overlapping with the lenses; The scattering portion is disposed around the lens in a cross-sectional view and at a boundary between two adjacent lenses. Detection device.

2. the plurality of lenses are disposed between the light guide plate and the optical filter layer; The detection device according to claim 1 .

3. the lens is disposed on a detection surface of the light guide plate opposite the optical filter layer. The detection device according to claim 1 .

4. the scattering portion is a plurality of convex portions protruding from the light guide plate toward the optical filter layer; The detection device according to any one of claims 1 to 3.

5. The detection device according to claim 4 , wherein the convex portion is provided in an area that does not overlap with the lens in a plan view.

6. The convex portion is covered with a reflective layer. The detection device according to claim 4.

7. a support layer that regulates the distance between the light guide plate and the optical filter layer; the convex portion is not in contact with the optical filter layer; The detection device according to claim 4.

8. The space between adjacent protrusions is a flat surface. The detection device according to claim 4.

9. an air layer is present between the light guide plate and the optical filter layer; The detection device according to claim 4.

10. the optical filter layer includes a plurality of light guide paths; the light guide path is disposed around one of the scattering sections in a plan view, the lenses are arranged in a staggered pattern in a plan view and overlap the openings; the scattering portion is disposed so as not to overlap with the opening and the lens; The detection device according to claim 1 .

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