Detection Device

Abstract

This detection device includes: a front light including a plurality of photodiodes arranged on a substrate, a light guide plate disposed overlapping the plurality of photodiodes, a light source that emits light on a first side surface of the light guide plate, and a plurality of scattering parts that are provided on the light guide plate and that scatter the light from the light source; and a light filter layer provided between the plurality of photodiodes and the light guide plate of the front light. The light filter layer includes: a plurality of light guide paths, of which at least a portion overlap the photodiodes; and a light-blocking part having a light absorption rate that is higher than that of the light guide paths. The plurality of scattering parts are provided in a region that is a surface of the light guide plate opposing the light filter layer and that overlaps the light-blocking part of the light filter layer.

Description

[Technical Field]

[0001] The present invention 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] In an optical sensor that has a front light provided between a detection object such as a finger and multiple photodiodes, it is necessary to guide light from the detection object such as a finger to the multiple photodiodes. The light emitted from the front light may be incident directly on the multiple photodiodes on the side opposite to the detection object such as a finger, which may reduce the detection contrast.

[0005] An object of the present invention 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 invention includes a front light having a plurality of photodiodes arranged on a substrate, a light guide plate arranged overlapping the plurality of photodiodes, a light source that irradiates light onto a first side of the light guide plate, and a plurality of scattering portions provided on the light guide plate that scatter light from the light source; and an optical filter layer provided between the plurality of photodiodes and the light guide plate of the front light, wherein the optical filter layer includes a plurality of light guide paths at least partially overlapping the photodiodes, and light-shielding portions having a higher light absorption rate than the light guide paths, and the plurality of scattering portions are provided on a surface of the light guide plate facing the optical filter layer in areas that overlap with the light-shielding portions of the optical filter layer. [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 positional relationship between the photodiode, the optical filter layer, and the plurality of scattering portions of the front light. [Figure 9] FIG. 9 is a cross-sectional view that schematically shows a cross section of a detection device according to a comparative example. [Figure 10] FIG. 10 is a perspective view schematically showing a detection device 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 second embodiment. [Figure 12] FIG. 12 is a plan view illustrating the arrangement of the photodiode, the optical filter layer, and the plurality of scattering sections of the front light in the detection device according to the second embodiment. [Figure 13] FIG. 13 is a cross-sectional view showing a schematic cross-sectional configuration of a detection device according to a third embodiment. [Figure 14] FIG. 14 is a cross-sectional view showing a schematic cross-sectional configuration of a detection device according to a fourth embodiment. [Figure 15] FIG. 15 is a cross-sectional view showing a schematic cross-sectional configuration of a detection device according to a fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Modes (embodiments) for carrying out the present invention 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 make 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 previously described with reference to the preceding 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 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 multiple photodiodes 30 and is disposed between the multiple photodiodes 30 and the light guide plate LG of the front light FL and a detected object FG such as a finger. The optical filter layer 50 has multiple light guide paths 51 and a light shielding portion 55 provided around the multiple light guide paths 51. At least a portion of the light guide paths 51 overlaps the photodiodes 30. The light shielding portion 55 has a higher light absorption rate than the light guide paths 51. The optical filter layer 50 is an optical element that transmits a component of light reflected by a detected object FG such as a finger and traveling in the third direction Dz toward the photodiodes 30. The optical filter layer 50 is also called a collimating aperture or a collimator.

[0013] 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.

[0014] 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.

[0015] 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.

[0016] The light guide plate LG is disposed so as to overlap the multiple photodiodes 30. The object to be detected FG is disposed facing the detection surface SF of the light guide plate LG. The multiple 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 multiple scattering portions SC11 are provided in areas overlapping with the light-shielding portions 55 of the optical filter layer 50. The scattering portions SC11 are dot-shaped concave or convex portions. The scattering portions SC11 may also be grooves.

[0017] 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 51 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.

[0018] 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 55 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 51, but is shielded by the light-shielding section 55.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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 periphery of the detection area AA and the outer edge of the substrate 21, where a plurality of photodiodes 30 are not provided.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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 sequentially or simultaneously selects multiple scanning lines GLS 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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."

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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 .

[0058] 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.

[0059] 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.

[0060] 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).

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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).

[0071] 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.

[0072] 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.

[0073] 8 is a plan view illustrating the positional relationship between the photodiode, the optical filter layer, and the plurality of scattering portions of the frontlight. In FIG. 8, the light-shielding portion 55 of the optical filter layer is shown with diagonal lines. The photodiode 30 is also shown schematically with 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 shown with diagonal lines to distinguish it from the light-shielding portion 55.

[0074] As shown in Fig. 8, the plurality of light guide paths 51 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 51 is capable of transmitting light. As shown in Figs. 8 and 2, each of the plurality of light guide paths 51 has a first opening 51a on the front light FL side and a second opening 51b (not shown in Fig. 8) on the photodiode 30 side. In this embodiment, the plurality of light guide paths 51 extend in the third direction Dz, and the second opening 51b is arranged to overlap the first opening 51a in a plan view. Furthermore, the second opening 51b has the same area as the first opening 51a.

[0075] The light absorptance of the light blocking portion 55 is higher than that of the plurality of light guide paths 51. In other words, the light transmittance of the plurality of light guide paths 51 is higher than that of the light blocking portion 55. The light blocking portion 55 is provided around the plurality of light guide paths 51 and is made of a material that does not easily transmit light. The light absorptance of the light blocking portion 55 is preferably 99% or more and 100% or less, and more preferably 100%. The light absorptance here 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.

[0076] The first openings 51a and second openings 51b of the plurality of light guides 51 are arranged so as to overlap the photodiodes 30. In Fig. 8, four light guides 51 are provided so as to overlap one photodiode 30. However, this is not limitative, and it is sufficient that at least one light guide 51 is provided so as to overlap one photodiode 30.

[0077] 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 may be smaller than the diameter of the light guide path 51. As described above, the scattering portions SC11 of the front light FL are provided in regions that overlap with the light blocking portions 55 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 51 of the optical filter layer 50.

[0078] Furthermore, the arrangement density of the scattering portions SC11 in the region overlapping with a plurality of light guides 51 is lower than the arrangement density of the scattering portions SC11 in the region overlapping with the light shielding portion 55. More specifically, in the region overlapping with one photodiode 30, the number of scattering portions SC11 overlapping with the light guide 51 (0 in the example shown in FIG. 8) is lower than the number of scattering portions SC11 overlapping with the light shielding portion 55 (9 in the example shown in FIG. 8).

[0079] 8, the number and diameter of the scattering portions SC11 are shown schematically to make the drawing easier to see, 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 51 of the optical filter layer 50, and may be provided so as to overlap with some of the light guide paths 51.

[0080] 9 is a cross-sectional view schematically illustrating a cross section of a detection device according to a comparative example. In detection device 100 of the comparative example, scattering portions SC11 of front light FL are provided in a region overlapping light guide path 51 and a region overlapping light blocking portion 55. In detection device 100 of the comparative example, light scattered by scattering portions SC11 overlapping light guide path 51 is likely to reach photodiode 30 directly.

[0081] 2 and 8, in this embodiment, the scattering portions SC11 of the front light FL are provided in an area overlapping with the light-shielding portions 55 of the optical filter layer 50, and are provided so as not to overlap with the light guide path 51. The area of the light guide plate LG of the front light FL that overlaps with the light guide path 51 is formed by a flat surface on which the scattering portions SC11 are not formed. As a result, light scattered upward (toward the object to be detected FG) by the scattering portions SC11 is reflected by the object to be detected FG, such as a finger, passes through the light guide path 51, and enters the photodiode 30.

[0082] On the other hand, light scattered by the scattering portions SC11 toward the optical filter layer 50 does not enter the light guide path 51 but is blocked by the light-shielding portions 55. Furthermore, the scattering portions SC11 are not provided in the region overlapping with the light guide path 51, or the number of scattering portions SC11 overlapping with the light guide path 51 is smaller than the number of light-shielding portions 55. Therefore, the light traveling inside the light guide plate LG is totally reflected in the region overlapping with the light guide path 51, and light that directly enters the light guide path 51 from the light guide plate LG of the front light FL can be suppressed. In other words, the detection device 1 can suppress external light other than the 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.

[0083] The configuration of the optical filter layer 50 can be changed as appropriate. For example, the light guide 51 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.

[0084] (Second embodiment) Fig. 10 is a perspective view showing a schematic diagram of a detection device according to a second embodiment. Fig. 11 is a cross-sectional view showing a schematic cross-sectional configuration of a detection device 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.

[0085] 10 and 11, in the detection device 1A according to the second embodiment, the front light FL has a light source LS1 and a light source LS2. The light sources LS1 are provided on a first side surface SD1 of the light guide plate LG, and the light sources LS2 are provided on a second side surface SD2 of the light guide plate LG opposite to the first side surface SD1.

[0086] The light guide plate LG has a first detection region AA1, a second detection region AA2, and a third detection region AA3 arranged side by side in the first direction Dx between a first side surface SD1 and a second side surface SD2. The first detection region AA1 is a region close to a light source LS1 provided on the first side surface SD1. The third detection region AA3 is a region close to a light source LS2 provided on the second side surface SD2. The second detection region AA2 is a region provided between the first detection region AA1 and the third detection region AA3, and is a region far from the light sources LS1 and LS2.

[0087] 12 is a plan view illustrating the positional relationship between the photodiode, the optical filter layer, and the multiple scattering portions of the front light in the detection device according to the second embodiment. Note that Fig. 12 shows a plan view of the first detection region AA1 and the second detection region AA2, and the third detection region AA3 is the same as the first detection region AA1 and is therefore not shown.

[0088] 11 and 12, the arrangement density of the scattering portions SC11 in the second detection region AA2, which is far from the light sources LS1 and LS2, is higher than the arrangement density of the scattering portions SC11 in the first detection region AA1 and the third detection region AA3, which are close to the light sources LS1 and LS2. That is, the number of scattering portions SC11 overlapping one photodiode 30 in the second detection region AA2 is greater than the number of scattering portions SC11 overlapping one photodiode 30 in the first detection region AA1. Similarly, as shown in FIG. 11, the number of scattering portions SC11 overlapping one photodiode 30 in the second detection region AA2 is greater than the number of scattering portions SC11 overlapping one photodiode 30 in the third detection region AA3.

[0089] 12, the arrangement pitch of the scattering members SC11 in the second detection area AA2 in the first direction Dx and the second direction Dy is about half the arrangement pitch of the scattering members SC11 in the first detection area AA1 in the first direction Dx and the second direction Dy. Although not shown in FIG. 12, the arrangement pitch of the scattering members SC11 in the third detection area AA3 is the same as that in the first detection area AA1.

[0090] As a result, in the detection device 1A according to the second embodiment, compared to a configuration in which scattering units SC11 are provided at the same arrangement density in the first detection region AA1, the second detection region AA2, and the third detection region AA3, more light is scattered by the scattering units SC11 in the second detection region AA2, which is farther from the light sources LS1 and LS2, thereby improving the light extraction efficiency. This makes it possible to prevent the occurrence of intensity distribution of light irradiated toward the finger or other detectable object FG among the first detection region AA1, the second detection region AA2, and the third detection region AA3. Therefore, the detection device 1A can reduce detection variations due to differences in distance from the light sources LS1 and LS2.

[0091] 11 and 12, in the first detection region AA1 and the third detection region AA3, similarly to the first embodiment described above, the scattering unit SC11 is provided in the region overlapping with the light blocking unit 55, but is not provided in the region overlapping with the light guide path 51. In the present embodiment, in the second detection region AA2, the scattering unit SC11 is provided in the region overlapping with the light blocking unit 55, and is also provided in the region overlapping with the light guide path 51.

[0092] As shown in FIG. 12, in the second detection area AA2, in the area overlapping one photodiode 30, the number of scattering portions SC11 overlapping with the light guide 51 (four in the example shown in FIG. 12) is smaller than the number of scattering portions SC11 overlapping with the light shielding portion 55 (21 in the example shown in FIG. 12). As a result, even in a configuration in which some of the scattering portions SC11 are provided in the area overlapping with the light guide 51, the light scattered by the scattering portions SC11 provided in the area overlapping with the light shielding portion 55 becomes dominant. The proportion of the light scattered by the scattering portions SC11 provided in the area overlapping with the light guide 51 is reduced to a small proportion of the total scattered light. Therefore, the detection device 1A can improve the light extraction efficiency in the second detection area AA2 and suppress a decrease in detection accuracy.

[0093] 12, the scattering unit SC11 provided in the region overlapping with the light guide 51 in the second detection region AA2 is positioned at the center of the light guide 51. However, FIG. 12 is merely an example, and the scattering unit SC11 may be positioned at a position offset from the center of the light guide 51. Furthermore, the relationship between the arrangement pitch of the scattering units SC11 in the second detection region AA2 and the arrangement pitch of the scattering units SC11 in the first detection region AA1 and the third detection region AA3 is also merely an example, and can be changed as appropriate depending on the detection accuracy required of the detection device 1A and the distance from the light sources LS1 and LS2.

[0094] (Third embodiment) FIG. 13 is a cross-sectional view showing a schematic cross-sectional configuration of a detection device according to the third embodiment. As shown in FIG. 13, in a detection device 1B according to the third embodiment, a front light FL has a reflective layer RF. The reflective layer RF is provided on the second side surface SD2 of the light guide plate LG. That is, in the third embodiment, a reflective layer RF is provided instead of the light source LS2 (see FIG. 11) shown in the second embodiment. Of the light emitted from the light source LS1, light that is not scattered by the scattering section SC11 and travels inside the light guide plate LG is reflected by the reflective layer RF on the second side surface SD2 and returns in the opposite direction (toward the first side surface SD1). This enables the detection device 1B according to the third embodiment to improve light utilization efficiency.

[0095] In this embodiment, the first detection region AA1, the second detection region AA2, and the third detection region AA3 are arranged in this order from the light source LS1. That is, the first detection region AA1 is provided in a position close to the light source LS1, and the third detection region AA3 is provided in a position farther from the light source LS1. Note that the second detection region AA2 is omitted in FIG. 13. In the front light FL, the arrangement density of the scattering portions SC11 (i.e., the number of scattering portions SC11 overlapping one photodiode 30) increases with increasing distance from the light source LS1. That is, the number of scattering portions SC11 overlapping one photodiode 30 increases in the order of the first detection region AA1, the second detection region AA2, and the third detection region AA3. In this embodiment, the scattering portions SC11 are provided in the region overlapping with the light-shielding portion 55, but are not provided in the region overlapping with the light guide path 51.

[0096] Furthermore, the arrangement pitch of the light guides 51 (and the light blocking portions 55) of the optical filter layer 50 is formed according to the arrangement density of the scattering portions SC11 of the front light FL. That is, the arrangement pitch P3 of the light guides 51 in the third detection region AA3 is smaller than the arrangement pitch P2 (not shown) of the light guides 51 in the second detection region AA2, and the arrangement pitch P2 of the light guides 51 in the second detection region AA2 is smaller than the arrangement pitch P1 of the light guides 51 in the first detection region AA1. In other words, the arrangement pitch of the light guides 51 decreases with increasing distance from the light source LS1. Note that while FIG. 13 shows the arrangement pitches P1 and P3 in the first direction Dx, the light guides 51 and the light blocking portions 55 are arranged in each region with a similar arrangement relationship in the second direction Dy as well.

[0097] The aspect ratio of the light guide 51 is also constant in the first detection region AA1, the second detection region AA2, and the third detection region AA3. That is, the thickness T3 of the light guide 51 in the third detection region AA3 is thinner than the thickness T2 (not shown) of the light guide 51 in the second detection region AA2, and the thickness T2 of the light guide 51 in the second detection region AA2 is thinner than the thickness T1 of the light guide 51 in the first detection region AA1. In other words, the thickness of the optical filter layer 50 decreases with increasing distance from the light source LS1. This reduces variation in the angle (angle with respect to the third direction Dz) of light transmitted through the light guide 51 and incident on the photodiode 30 between the first detection region AA1, the second detection region AA2, and the third detection region AA3. In other words, the optical filter layer 50 can reduce variation in light transmission performance among the first detection region AA1, the second detection region AA2, and the third detection region AA3, which are located at different distances from the light source LS1. As a result, the detection device 1B can suppress variations in detection accuracy.

[0098] 13 shows only a portion of the optical filter layer 50, the thicknesses T1, T2, and T3 of the light guide 51 may be formed so as to become gradually thinner in each predetermined region, or may be formed so as to become continuously thinner from the first side surface SD1 (first detection region AA1) to the second side surface SD2 (third detection region AA3). The reflective layer RF may also be omitted. The reflective layer RF may also be combined with the detection device 1 of the first embodiment described above.

[0099] (Fourth embodiment) Fig. 14 is a cross-sectional view showing a schematic cross-sectional configuration of a detection device according to the fourth embodiment. As shown in Fig. 14, in the detection device 1C according to the fourth embodiment, similar to the second embodiment (see Figs. 10 and 11), the front light FL has a light source LS1 and a light source LS2. The plurality of light sources LS1 are provided on a first side surface SD1 of the light guide plate LG, and the plurality of light sources LS2 are provided on a second side surface SD2 of the light guide plate LG.

[0100] Furthermore, the scattering portions SC11 are arranged at a higher density in the central portion of the front light FL in the first direction Dx, which is far from the light sources LS1 and LS2, than at both ends in the first direction Dx, which are closer to the light sources LS1 and LS2. That is, the number of scattering portions SC11 overlapping one photodiode 30 in the second detection region AA2 is greater than the number of scattering portions SC11 overlapping one photodiode 30 in the first detection region AA1. Similarly, the number of scattering portions SC11 overlapping one photodiode 30 in the second detection region AA2 is greater than the number of scattering portions SC11 overlapping one photodiode 30 in the third detection region AA3.

[0101] 14, in this embodiment, the scattering portion SC11 is provided in a region overlapping with the light shielding portion 55, but is not provided in a region overlapping with the light guide path 51. However, a part of the scattering portion SC11 may be provided in the region overlapping with the light guide path 51.

[0102] The arrangement pitch of the light guides 51 (and the light blocking portions 55) of the optical filter layer 50 is determined according to the arrangement density of the scattering portions SC11 of the frontlight FL. That is, the arrangement pitch P2 of the light guides 51 in the second detection region AA2 is smaller than the arrangement pitch P1 of the light guides 51 in the first detection region AA1. The arrangement pitch P2 of the light guides 51 in the second detection region AA2 is smaller than the arrangement pitch P3 of the light guides 51 in the third detection region AA3. In other words, the arrangement pitch of the light guides 51 decreases with increasing distance from the light source LS1 and the light source LS2. Note that while FIG. 14 shows the arrangement pitches P1, P2, and P3 in the first direction Dx, the light guides 51 and the light blocking portions 55 are similarly arranged in the second direction Dy.

[0103] Similarly to the third embodiment, the aspect ratio of the light guide 51 is constant in each of the first detection region AA1, the second detection region AA2, and the third detection region AA3. That is, the thickness T2 of the light guide 51 in the second detection region AA2 is thinner than the thickness T1 of the light guide 51 in the first detection region AA1, and the thickness T2 of the light guide 51 in the second detection region AA2 is thinner than the thickness T3 of the light guide 51 in the third detection region AA3. In other words, the thickness of the optical filter layer 50 decreases with increasing distance from the light source LS1 and the light source LS2. This reduces variation in the angle (angle with respect to the third direction Dz) of light passing through the light guide 51 and incident on the photodiode 30 between the first detection region AA1, the second detection region AA2, and the third detection region AA3, even in a configuration in which the light sources LS1 and LS2 are provided at both ends of the light guide plate LG. This reduces variation in detection accuracy in the detection device 1C.

[0104] (Fifth embodiment) Fig. 15 is a cross-sectional view showing a schematic cross-sectional configuration of a detection device according to a fifth embodiment. In each of the above-described embodiments, the scattering portion SC11 of the front light FL is formed of dot-shaped convex portions, but this is not limiting. As shown in Fig. 15, in a detection device 1D according to the fifth embodiment, the scattering portion SC21 may have a prism shape (triangular concave or convex portions).

[0105] In this embodiment, similarly to the first embodiment described above, the scattering portions SC21 are provided in regions overlapping with the light-shielding portions 55 of the optical filter layer 50. However, without being limited to this, the prism-shaped scattering portions SC21 can be applied to any of the second to fourth embodiments.

[0106] In the above-described embodiments, the optical filter layer 50 has a light-guiding columnar structure in which the light guide paths are formed in a columnar shape. However, the present invention is not limited to this structure, and various other structures can be applied. For example, the optical filter layer 50 may have a multi-layer pinhole structure in which light-shielding layers with a plurality of pinholes and light-transmitting resin layers are alternately stacked. Alternatively, the optical filter layer 50 may be configured by solidifying a plurality of light-transmitting optical fibers with a colored resin layer (light-shielding portion 55). Alternatively, the optical filter layer 50 may have a structure in which light-shielding layers and light-transmitting layers are stacked in a louvered shape and arranged orthogonally. Alternatively, the optical filter layer 50 may be provided with microlenses as needed.

[0107] Although preferred embodiments of the present invention have been described above, the present invention is not limited to such embodiments. The contents disclosed in the embodiments are merely examples, and various modifications are possible without departing from the spirit of the present invention. Appropriate modifications made without departing from the spirit of the present invention naturally fall within the technical scope of the present invention. At least one of various omissions, substitutions, and modifications of components can be made without departing from the spirit of each of the above-described embodiments and modifications. [Explanation of symbols]

[0108] 1, 1A, 1B, 1C, 1D 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 layers 51 Light guide 55 Light blocking section AA detection area AA1 First detection area AA2 Second detection area AA3 Third detection area GA peripheral area FL Front Light LG light guide plate LS, LS1, LS2 light source SD1 1st side SD2 2nd side SC11, SC21 scattering section

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 provided between the plurality of photodiodes and the light guide plate of the front light; the optical filter layer includes a plurality of light guide paths at least partially overlapping the photodiode, and a light shielding portion having a higher light absorption rate than the light guide paths, the scattering portions are provided on a surface of the light guide plate facing the optical filter layer, in regions overlapping with the light-shielding portions of the optical filter layer; the light guide plate has a first detection area and a second detection area that is farther from the light source than the first detection area, the number of the scattering portions overlapping one of the photodiodes in the second detection region is greater than the number of the scattering portions overlapping one of the photodiodes in the first detection region; the light source is provided on the first side surface of the light guide plate corresponding to the first detection area, a reflective layer provided on a second side surface of the light guide plate opposite to the first side surface; Detection device.

2. 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 provided between the plurality of photodiodes and the light guide plate of the front light; the optical filter layer includes a plurality of light guide paths at least partially overlapping the photodiode, and a light shielding portion having a higher light absorption rate than the light guide paths, the scattering portions are provided on a surface of the light guide plate facing the optical filter layer, in regions overlapping with the light-shielding portions of the optical filter layer; the light guide plate has a first detection area and a second detection area that is farther from the light source than the first detection area, The arrangement pitch of the light guide paths in the second detection region is smaller than the arrangement pitch of the light guide paths in the first detection region. Detection device.

3. 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 provided between the plurality of photodiodes and the light guide plate of the front light; the optical filter layer includes a plurality of light guide paths at least partially overlapping the photodiode, and a light shielding portion having a higher light absorption rate than the light guide paths, the scattering portions are provided on a surface of the light guide plate facing the optical filter layer, in regions overlapping with the light-shielding portions of the optical filter layer; the light guide plate has a first detection area and a second detection area that is farther from the light source than the first detection area, The thickness of the light guide plate in the second detection area is thinner than the thickness of the light guide plate in the first detection area. Detection device.

4. 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 provided between the plurality of photodiodes and the light guide plate of the front light; the optical filter layer includes a plurality of light guide paths at least partially overlapping the photodiode, and a light shielding portion having a higher light absorption rate than the light guide paths, the scattering portions are provided on a surface of the light guide plate facing the optical filter layer, in regions overlapping with the light-shielding portions of the optical filter layer; a plurality of the light sources; the plurality of light sources are provided on the first side surface of the light guide plate and on a second side surface opposite to the first side surface, the light guide plate has a first detection area, a second detection area, and a third detection area arranged between the first side surface and the second side surface, The number of the scattering portions overlapping one photodiode in the second detection region is greater than the number of the scattering portions overlapping one photodiode in the first detection region, and is greater than the number of the scattering portions overlapping one photodiode in the third detection region. Detection device.

5. 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 provided between the plurality of photodiodes and the light guide plate of the front light; the optical filter layer includes a plurality of light guide paths at least partially overlapping the photodiode, and a light shielding portion having a higher light absorption rate than the light guide paths, the scattering portions are provided on a surface of the light guide plate facing the optical filter layer, in regions overlapping with the light-shielding portions of the optical filter layer; a plurality of the light sources; the plurality of light sources are provided on the first side surface of the light guide plate and on a second side surface opposite to the first side surface, the light guide plate has a first detection area, a second detection area, and a third detection area arranged between the first side surface and the second side surface, The arrangement pitch of the light guide paths in the second detection region is smaller than the arrangement pitch of the light guide paths in the first detection region and the arrangement pitch of the light guide paths in the third detection region. Detection device.

6. 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 provided between the plurality of photodiodes and the light guide plate of the front light; the optical filter layer includes a plurality of light guide paths at least partially overlapping the photodiode, and a light shielding portion having a higher light absorption rate than the light guide paths, the scattering portions are provided on a surface of the light guide plate facing the optical filter layer, in regions overlapping with the light-shielding portions of the optical filter layer; a plurality of the light sources; the plurality of light sources are provided on the first side surface of the light guide plate and on a second side surface opposite to the first side surface, the light guide plate has a first detection area, a second detection area, and a third detection area arranged between the first side surface and the second side surface, The thickness of the light guide plate in the second detection region is thinner than the thickness of the light guide plate in the first detection region and the thickness of the light guide plate in the third detection region. Detection device.

7. The number of the scattering portions overlapping one of the photodiodes in the second detection region is greater than the number of the scattering portions overlapping one of the photodiodes in the first detection region. The detection device according to any one of claims 2 to 6.

8. In a region overlapping one of the photodiodes, the number of the scattering portions overlapping with the plurality of light guide paths is smaller than the number of the scattering portions overlapping with the light blocking portion. The detection device according to any one of claims 1 to 6.

9. The scattering portions are provided in an area of the optical filter layer that does not overlap with the light guide path. The detection device according to any one of claims 1 to 6.

10. The scattering portion is in the form of a dot or a prism. The detection device according to any one of claims 1 to 6.

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