Detection device

Abstract

This detection device has: a plurality of photodiodes that are arrayed on a substrate; a front light that has a light guide plate disposed so as to overlap the plurality of photodiodes and a light source emitting light onto a side surface of the light guide plate; and an optical filter layer that is 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 of which at least some are superimposed on the photodiodes and a light shielding part which has a higher absorptance of light than the light guide paths, and there is a reflection layer that is between the light guide plate and the optical filter layer and that is provided to a region overlapping the light shielding part of the optical 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, Patent Documents 1 and 2). The optical sensors described in Patent Documents 1 and 2 have a front light provided in front of a plurality of photodiodes. The optical sensor described in Patent Document 2 has a collimator having a plurality of light guide paths and a light blocking portion provided between the plurality of photodiodes and the front light. [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, light from the detection object such as a finger must be guided to the multiple photodiodes. Light emitted from the front light may be directly incident on the multiple photodiodes on the side opposite the detection object such as a finger, potentially reducing the detection contrast. Furthermore, in an optical sensor that has a collimator, some of the light emitted from the front light may be absorbed by the light-shielding portion of the collimator, potentially reducing the light utilization efficiency.

[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 comprises a front light having a plurality of photodiodes arranged on a substrate, a light guide plate arranged overlapping the plurality of photodiodes, and a light source that irradiates light onto a side surface of the light guide plate, 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 that at least partially overlap the photodiodes, and a light-shielding portion that has a higher light absorption rate than the light guide paths, and has a reflective layer provided between the light guide plate and the optical filter layer in a region that overlaps with the light-shielding portion 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 reflective layer. [Figure 9] FIG. 9 is a cross-sectional view schematically showing a cross section of a detection device according to a comparative example. [Figure 10] FIG. 10 is a cross-sectional view showing a schematic cross-sectional configuration of a detection device according to the second embodiment. [Figure 11] FIG. 11 is a cross-sectional view showing a scattering section of a detection device according to the second embodiment. [Figure 12] FIG. 12 is a cross-sectional view showing a schematic cross-sectional configuration of a detection device according to the third embodiment. [Figure 13] FIG. 13 is a cross-sectional view showing a schematic cross-sectional configuration of a detection device according to a fourth embodiment. [Figure 14] FIG. 14 is a cross-sectional view showing an inclined portion of a reflective layer of a detection device according to a fourth embodiment. [Figure 15] FIG. 15 is a perspective view schematically showing a detection device according to a fifth embodiment. [Figure 16] FIG. 16 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 prism-shaped (triangular) concave or convex portions. However, the scattering portions SC11 may also be dot-shaped concave or convex portions.

[0017] The detection device 1 has a reflective layer 56 provided between the light guide plate LG and the optical filter layer 50. The reflective layer 56 is provided in an area overlapping with the light-shielding portion 55 of the optical filter layer 50. The reflective layer 56 is not provided in an area overlapping with the light guide path 51 of the optical filter layer 50. The reflective layer 56 is a plate-like member made of a metal material, and is provided parallel to the surface of the light guide plate LG that faces the optical filter layer 50. The reflective layer 56 is provided directly on and in contact with the light-shielding portion 55. However, the present invention is not limited to this, and the reflective layer 56 may be provided on the light-shielding portion 55 via a resin layer or the like.

[0018] 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.

[0019] 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 that faces the light guide plate LG. Since the scattering section SC11 is provided in an area that overlaps with the light-shielding section 55 and the reflective layer 56 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 reflected by the reflective layer 56 and returns to the light guide plate LG.

[0020] 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 multiple photodiodes 30 on the side opposite the object to be detected FG is suppressed. Therefore, the detection device 1 having the front light FL can improve detection accuracy. Furthermore, the light scattered by the scattering section SC11 toward the optical filter layer 50 is not absorbed by the light-shielding section 55 of the optical filter layer 50, but is reflected by the reflective layer 56 and reused. As a result, the detection device 1, which is provided with the reflective layer 56, can improve light utilization efficiency.

[0021] 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.

[0022] 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.

[0023] 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 control signals to the front light FL (see FIGS. 1 and 2) to control the lighting or non-lighting of the light source LS. 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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 (Detection processing circuit) 40. Some or all of the functions of the detection control circuit 11 are included in the 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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."

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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 .

[0059] 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.

[0060] 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.

[0061] 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).

[0062] 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.

[0063] 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.

[0064] The upper electrode 34 is the cathode of the photodiode 30 and is an electrode for supplying the power supply potential SVS to the photoelectric conversion layer. Multiple The upper electrode 34 is a light-transmitting conductive layer such as ITO, and In response to It will be established.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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).

[0072] 7 shows one terminal portion 72, but a plurality of terminal portions 72 are arranged at intervals. The plurality of terminal portions 72 are connected to the wiring board 510 (see FIG. 7) by, for example, anisotropic conductive film (ACF) or the like. 3 ) is electrically connected to the

[0073] 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.

[0074] 8 is a plan view illustrating the positional relationship between the photodiode, the optical filter layer, and the reflective layer. In FIG. 8, the light-shielding portion 55 of the optical filter layer is indicated by diagonal lines. 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.

[0075] 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 (see Fig. 2) 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.

[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] The light absorptance of the light blocking portion 55 is higher than the light absorptance 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 the light transmittance 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 absorptance of incident light. L It 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 in.

[0078] In plan view, the reflective layer 56 is provided in an area overlapping with the light-shielding portion 55 of the optical filter layer 50. More preferably, the reflective layer 56 is provided to cover the entire area of ​​the light-shielding portion 55, and openings are provided in the areas overlapping with the plurality of light guide paths 51, respectively.

[0079] 8, the scattering portions SC11 (see FIG. 2) are omitted from the illustration, but as described above, the scattering portions SC11 are provided in the regions overlapping with the light-shielding portions 55 of the optical filter layer 50, i.e., the regions overlapping with the reflective layer 56. The arrangement pitch, number, arrangement density, etc. of the scattering portions SC11 can be changed as appropriate depending on the characteristics required of the detection device 1.

[0080] 9 is a cross-sectional view schematically illustrating a cross section of a detection device according to a comparative example. In the detection device 100 according to the comparative example, the scattering portions SC11 of the front light FL are provided in a region overlapping the light guide 51 and a region overlapping the light blocking portion 55. In the detection device 100 according to the comparative example, light scattered by the scattering portions SC11 overlapping the light guide 51 is likely to reach the photodiode 30 directly. Furthermore, in the detection device 100 according to the comparative example, the reflective layer 56 is not provided in a region of the optical filter layer 50 overlapping the light blocking portion 55. Therefore, in the detection device 100 according to the comparative example, the light scattered by the scattering portions SC11 overlapping the light blocking portion 55 is absorbed by the light blocking portion 55, reducing the light utilization efficiency.

[0081] 2 and 8 , in this embodiment, the reflective layer 56 is provided between the light guide plate LG and the optical filter layer 50 and in a region overlapping with the light-shielding portion 55 of the optical filter layer 50. Furthermore, the scattering portion SC11 of the front light FL is provided in a region overlapping with the light-shielding portion 55 of the optical filter layer 50, and is provided so as not to overlap with the light guide path 51. The region 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 portion SC11 is not formed. As a result, light scattered upward (toward the object to be detected FG) by the scattering portion 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, the light scattered by the scattering section SC11 toward the optical filter layer 50 does not enter the light guide path 51, but is reflected by the reflective layer 56 provided on the light shielding section 55. In other words, the light scattered by the scattering section SC11 is not absorbed by the light shielding section 55, but is reflected by the reflective layer 56 and enters the light guide plate LG, where it is reused. This allows the detection device 1 to improve the light utilization efficiency.

[0083] Furthermore, in this embodiment, the scattering portion SC11 is not provided in the region overlapping with the light guide path 51. Therefore, the light traveling inside the light guide plate LG is totally reflected in the region overlapping with the light guide path 51, and it is possible to suppress light that directly enters the light guide path 51 from the light guide plate LG of the front light FL. 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.

[0084] 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.

[0085] (Second embodiment) 10 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 embodiment are denoted by the same reference numerals, and redundant description will be omitted.

[0086] As shown in FIG. 10 , the detection device 1A according to the second embodiment includes a light-transmitting resin layer 57 and an adhesive layer 58 provided between the light guide plate LG and the optical filter layer 50. The light-transmitting resin layer 57 is provided between the reflective layer 56 and the light guide plate LG. More specifically, the light-transmitting resin layer 57 is provided in a region overlapping the light-shielding portion 55 of the optical filter layer 50 and is in direct contact with the reflective layer 56. The light guide path 51 of the optical filter layer 50 is made of a light-transmitting resin, and an opening 57a is provided in the light-transmitting resin layer 57 between the light guide plate LG and the optical filter layer 50 and in a region overlapping the light guide path 51 of the optical filter layer 50. The opening 57a in the light-transmitting resin layer 57 is formed of an air layer. That is, the light-transmitting resin layer 57 is not provided in a region overlapping the light guide path 51 of the optical filter layer 50.

[0087] The light-transmitting resin layer 57 and the light guide plate LG are bonded together via an adhesive layer 58. The surface of the light guide plate LG facing the optical filter layer 50 is formed flat. That is, the scattering portions SC12 are not provided on the surface of the light guide plate LG facing the optical filter layer 50, but on the detection surface SF (the side opposite to the surface facing the optical filter layer 50). The adhesive layer 58 is provided on the surface of the light guide plate LG facing the optical filter layer 50, and is in contact with the light-transmitting resin layer 57. The adhesive layer 58 is also provided in a region overlapping with the light guide path 51 of the optical filter layer 50 and a region overlapping with the opening 57a of the light-transmitting resin layer 57.

[0088] Light propagating within the light guide plate LG is totally reflected at the interface between the adhesive layer 58 on the surface of the light guide plate LG facing the optical filter layer 50 and the air layer (openings 57a in the light-transmitting resin layer 57) in the region overlapping with the light guide path 51, and does not enter the photodiode 30. Light propagating within the light guide plate LG enters the light-transmitting resin layer 57 in the region overlapping with the light-shielding portion 55, and is repeatedly reflected at the interface between the light-transmitting resin layer 57 and the air layer (openings 57a in the light-transmitting resin layer 57) and the reflective layer 56, before returning into the light guide plate LG.

[0089] A part of the light propagating through the light guide plate LG is scattered by the scattering portion SC12 provided on the detection surface SF and emitted to the detection object FG. The light reflected by the detection object FG passes through the light guide plate LG and the light guide path 51 and enters the photodiode 30.

[0090] Fig. 11 is a cross-sectional view showing the scattering unit of the detection device according to the second embodiment. As shown in Fig. 11, the inclined surface SC12a of the scattering unit SC12 is inclined at an angle θp with respect to the horizontal line HL. The horizontal line HL is an imaginary line parallel to the detection surface SF.

[0091] Light L1in propagating within the light guide plate LG has an incident angle of θ1 or more with respect to the normal VL of the detection surface SF. The angle θ1 is the angle of total reflection at the detection surface SF. If the refractive index n1 of the light guide plate LG is, for example, n1=1.88 and the refractive index n2 of air is n2=1, then the angle θ1 is θ1=32.1° or more.

[0092] Light L1in is incident at an angle θ4 with respect to the normal NL of the inclined surface SC12a. The angle θ4 is expressed as θ4 = θp - θ1. According to Snell's law, light L1out emitted from the scattering unit SC12 is emitted at an angle θ2 with respect to the normal NL of the inclined surface SC12a in the direction opposite to the incident direction of light L1in. In the example shown in FIG. 11, light L1out travels in a direction parallel to the normal VL of the detection surface SF. In this case, the angle θ2 is θ2 = θp. The angle θ3 formed between the normal NL of the inclined surface SC12a and the horizontal line HL is expressed as θ3 = 90° - θ2 = 90° - θp. With this configuration, light L1 propagating within the light guide plate LG is emitted by the scattering unit SC12 toward the detection object FG.

[0093] The shape of the scattering section SC12 and the angles such as the angle θp of the inclined surface SC12a are merely examples and can be changed as appropriate.

[0094] In this embodiment, the light in the region overlapping with the light-shielding portion 55 can be totally reflected by the light-transmitting resin layer 57 and the reflective layer 56. In addition, the scattering portion SC12 is provided on the detection surface SF of the light guide plate LG. This increases the degree of freedom in positioning the light guide plate LG and the optical filter layer 50 compared to the first embodiment described above, and makes it easier to manufacture the detection device 1A.

[0095] (Third embodiment) Fig. 12 is a cross-sectional view showing a schematic cross-sectional configuration of a detection device according to the third embodiment. As shown in Fig. 12, the detection device 1B according to the third embodiment does not have a light-transmitting resin layer 57, unlike the second embodiment described above. That is, the light guide plate LG and the reflective layer 56 are bonded together via an adhesive layer 58. Furthermore, the scattering section SC12 is provided on the detection surface SF of the light guide plate LG.

[0096] In this embodiment, the light guide 51A of the optical filter layer 50 is formed of an air layer. An air layer is provided in a region between the optical filter layer 50 and the adhesive layer 58 that overlaps with the light guide 51A, i.e., in the opening 56a of the reflective layer 56. The light guide 51A formed of the air layer and the opening 56a of the reflective layer 56 are connected in the third direction Dz.

[0097] With this configuration, in the region overlapping with the light guide path 51A, light propagating within the light guide plate LG is totally reflected at the interface between the adhesive layer 58 provided on the surface of the light guide plate LG facing the optical filter layer 50 and the air layer provided in the opening 56a of the reflective layer 56, and does not enter the photodiode 30. Furthermore, in the region overlapping with the light shielding portion 55, light propagating within the light guide plate LG is reflected by the reflective layer 56 and returns into the light guide plate LG. Note that the configuration in which the light guide path 51A of the optical filter layer 50 is formed with an air layer is not limited to this embodiment and may be combined with other embodiments.

[0098] (Fourth embodiment) Fig. 13 is a cross-sectional view showing a schematic cross-sectional configuration of a detection device according to Embodiment 4. Fig. 14 is a cross-sectional view showing an inclined portion of a reflective layer of a detection device according to Embodiment 4.

[0099] 13, in the detection device 1C according to the fourth embodiment, support parts 59 are provided in regions overlapping with the light-shielding parts 55 between the light guide plate LG and the optical filter layer 50. An inclined surface and a flat surface are formed in each region on the surface of the support parts 59 facing the light guide plate LG.

[0100] The reflective layer 56 is provided on the surface of the support portion 59 facing the light guide plate LG. The reflective layer 56 has an inclined portion provided along the inclined surface of the support portion 59 and a flat portion provided along the flat surface of the support portion 59. The inclined portion of the reflective layer 56 is provided at an angle with respect to the surface facing the optical filter layer 50 of the light guide plate LG. The flat portion of the reflective layer 56 is provided parallel to the surface facing the optical filter layer 50 of the light guide plate LG. The inclined and flat portions of the reflective layer 56 are arranged with different area ratios in each region. For example, the reflective layer 56b is composed of multiple inclined portions. The reflective layer 56c has no inclined portions and is composed of flat portions. The reflective layer 56d is provided with a mixture of inclined and flat portions.

[0101] The light guide plate LG and the reflective layer 56 are bonded together via an adhesive layer 58. The adhesive layer 58 has a thickness that can absorb the difference in height between the inclined portion and the flat portion of the reflective layer 56. An air layer is provided in the region between the optical filter layer 50 and the adhesive layer 58 that overlaps with the light guide path 51, i.e., in the opening 59a of the support portion 59.

[0102] In this embodiment, the inclined portions of the reflective layer 56 also function as the scattering portions SC11 and SC12 (see FIGS. 2 and 10) in the above-described embodiments. That is, in this embodiment, the surface of the light guide plate LG facing the optical filter layer 50 and the detection surface SF are each formed as a flat surface, and the scattering portions SC11 and SC12 are not provided.

[0103] With this configuration, light propagating within the light guide plate LG is totally reflected at the interface between the adhesive layer 58 provided on the surface of the light guide plate LG facing the optical filter layer 50 and the air layer (openings 59a of the support portion 59) in the region overlapping with the light guide path 51, and does not enter the photodiode 30. Furthermore, light propagating within the light guide plate LG is reflected by the inclined portion of the reflective layer 56 in the region overlapping with the light shielding portion 55. The light reflected by the inclined portion of the reflective layer 56 has its traveling direction changed to the third direction Dz side, and is emitted toward the detection object FG.

[0104] 14, the inclined portion of the reflective layer 56 is inclined at an angle θ14 with respect to the horizontal line HLa. The angle θ14 of the inclined portion of the reflective layer 56 is, for example, θ14 = 18.0°. The adhesive layer 58 is provided in contact with the inclined portion of the reflective layer 56 and covers the entire inclined portion.

[0105] Light L1in propagating within the light guide plate LG has an incident angle of θ1 or more with respect to the normal VLa of the detection surface SF. The angle θ1 is the angle of total reflection at the detection surface SF. If the refractive index n1 of the light guide plate LG is, for example, n1=1.49 and the refractive index n2 of air is n2=1, then the angle θ1 is θ1=42.2° or more.

[0106] The light L1in is refracted at the interface between the light guide plate LG and the adhesive layer 58 in accordance with Snell's law, and travels through the adhesive layer 58 at an angle θ12 with respect to the normal VLb to the interface between the light guide plate LG and the adhesive layer 58. When the refractive index n3 of the adhesive layer 58 is, for example, n3=1.70, the angle θ12 is θ12=36.0°.

[0107] Light L1in in the adhesive layer 58 is incident at an angle θ13 with respect to the normal NLa of the inclined portion of the reflective layer 56. Light L1out reflected by the inclined portion of the reflective layer 56 is emitted at an angle θ13 in the opposite direction to the incident direction of light L1in with respect to the normal NLa. In the example shown in FIG. 14, light L1out travels in a direction parallel to the normal VLa of the detection surface SF. In this case, the angle θ13 is θ13 = (½) × θ12 = 18.0°. With this configuration, light L1 propagating within the light guide plate LG is emitted by the inclined portion of the reflective layer 56 toward the detection object FG.

[0108] In the detection device 1C of this embodiment, the inclined portions of the reflective layer 56 having the functions of the scattering sections SC11 and SC12 (see FIGS. 2 and 10) are provided on the optical filter layer 50 side. Therefore, in the detection device 1C according to the fourth embodiment, high positional accuracy between the light guide plate LG and the optical filter layer 50 is not required, compared to the above-described embodiments.

[0109] (Fifth embodiment) Fig. 15 is a perspective view schematically showing a detection device according to a fifth embodiment, and Fig. 16 is a cross-sectional view showing a schematic cross-sectional configuration of the detection device according to the fifth embodiment.

[0110] 15 and 16, in a detection device 1D according to the fifth embodiment, a light guide plate LG has a first detection region AA1 and a second detection region AA2 arranged side by side in a first direction Dx. The first detection region AA1 is a region closer to the light source LS. The second detection region AA2 is a region farther from the light source LS than the first detection region AA1.

[0111] 16, the area of ​​the flat portion of the reflective layer 56 in the first detection region AA1 close to the light source LS is larger than the area of ​​the flat portion of the reflective layer 56 in the second detection region AA2 far from the light source LS. In other words, the area (arrangement density) of the inclined portions of the reflective layer 56 in the second detection region AA2 far from the light source LS is larger than the area (arrangement density) of the inclined portions of the reflective layer 56 in the first detection region AA1 close to the light source LS. In this embodiment, the area of ​​the flat portion of the reflective layer 56 and the area of ​​the inclined portions of the reflective layer 56 are compared based on the area of ​​the region that overlaps with one photodiode 30.

[0112] Specifically, in the first detection area AA1, a reflective layer 56b composed of a plurality of inclined portions, a reflective layer 56c composed of a flat portion without inclined portions, and a reflective layer 56d provided with a mixture of inclined portions and flat portions are arranged side by side in the first direction Dx. In the second detection area AA2, the reflective layer 56c and the reflective layer 56d are not provided, and only the reflective layer 56b composed of a plurality of inclined portions is arranged side by side in the first direction Dx.

[0113] As a result, in the detection device 1D according to the fifth embodiment, compared to a configuration in which the flat and inclined portions of the reflective layer 56 are provided at the same arrangement density in the first detection area AA1 and the second detection area AA2, more light is reflected by the inclined portions of the reflective layer 56 toward the object to be detected FG in the third direction Dz in the second detection area AA2, which is farther from the light source LS, and the light extraction efficiency can be improved. As a result, the intensity distribution of light irradiated toward the object to be detected FG, such as a finger, between the first detection area AA1 and the second detection area AA2 Difference Therefore, the detection device 1D can suppress the detection variation caused by the difference in distance from the light source LS.

[0114] 16, in the detection device 1D according to the fifth embodiment, the arrangement pitches P1, P2 of the reflective layers 56 and the light-shielding portions 55 are different between the first detection region AA1 and the second detection region AA2, and the element sizes (widths W1, W2) of the photodiodes 30 are also different. Specifically, the arrangement pitch P2 of the reflective layers 56 and the light-shielding portions 55 in the second detection region AA2 is larger than the arrangement pitch P1 of the reflective layers 56 and the light-shielding portions 55 in the first detection region AA1. In other words, the diameter of the light guide path 51 in the second detection region AA2 is larger than the diameter of the light guide path 51 in the first detection region AA1. Furthermore, the width W2 of the photodiode 30 in the second detection region AA2 in the first direction Dx is larger than the width W1 of the photodiode 30 in the first direction Dx in the first detection region AA1.

[0115] As a result, the light capture angle θin in the second detection area AA2 is larger than that in the first detection area AA1. The light capture angle θin is the angular range of light that is reflected by the object FG and can pass through the light guide path 51 and enter the photodiode 30. By increasing the light capture angle θin, the amount of light incident on the photodiode 30 can be increased even in a configuration in which the scattering sections SC11 and SC12 are not provided in the area of ​​the light guide plate LG that overlaps with the light guide path 51. Furthermore, in the second detection area AA2, which is far from the light source LS, the amount of light incident on one photodiode 30 can be increased, thereby correcting the difference in light amount between the first detection area AA1 and the second detection area AA2.

[0116] 16 shows a configuration in which the area of ​​the flat portion of the reflective layer 56 is different between the first detection region AA1 and the second detection region AA2, and the arrangement pitches P1 and P2 of the reflective layer 56 and the light-shielding portions 55 and the element size (widths W1 and W2) of the photodiodes 30 are different. However, this is not limiting, and the arrangement pitches P1 and P2 of the reflective layer 56 and the light-shielding portions 55 and the element size (widths W1 and W2) of the photodiodes 30 may be the same between the first detection region AA1 and the second detection region AA2. Furthermore, the configuration in which the arrangement pitches P1 and P2 of the reflective layer 56 and the light-shielding portions 55 are different between the first detection region AA1 and the second detection region AA2, and the configuration in which the element size (widths W1 and W2) of the photodiodes 30 are different between the first detection region AA1 and the second detection region AA2 may be combined with each of the first to fourth embodiments described above.

[0117] In the above-described embodiments, the optical filter layer 50 has a light-guiding columnar structure in which the light guide paths 51 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, each having 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.

[0118] 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]

[0119] 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 layer 51 Light guide 55 Light blocking section 56 Reflective layer 57 Translucent resin layer 58 Adhesive layer 59 Support part AA detection area AA1 First detection area AA2 Second detection area GA peripheral area FL Front Light LG light guide plate LS light source SC11, SC12 scattering part

Claims

1. a plurality of photodiodes arranged on a substrate; a front light including a light guide plate disposed so as to overlap a plurality of photodiodes and a light source that irradiates light onto a side surface of the light guide plate; 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, a reflective layer provided between the light guide plate and the optical filter layer and in a region overlapping the light-shielding portion of the optical filter layer; a plurality of scattering portions provided on the light guide plate for scattering light from the light source; the scattering portions are provided on a surface of the light guide plate facing the optical filter layer, in an area overlapping the light blocking portion and the reflective layer of the optical filter layer; The scattering portions scatter the light propagating through the light guide plate toward the reflective layer and toward the object to be detected on the opposite side to the reflective layer. Detection device.

2. The reflective layer and the light guide plate are bonded together via an adhesive layer. The detection device according to claim 1 .

3. A light-transmitting resin layer is provided between the reflective layer and the light guide plate. The detection device according to claim 1 .

4. The plurality of scattering portions are provided on a surface of the light guide plate opposite to a surface facing the optical filter layer. The detection device according to claim 2 .

5. The plurality of scattering portions are provided on a surface of the light guide plate opposite to a surface facing the optical filter layer. The detection device according to claim 3 .

6. the light guide path of the optical filter layer is made of a light-transmitting resin; An air layer is provided between the light guide plate and the optical filter layer and in a region where the optical filter layer overlaps with the light guide path. The detection device according to claim 1 .

7. The light guide path of the optical filter layer is an air layer. The detection device according to claim 1 .

8. A plurality of photodiodes arranged on a substrate; a front light including a light guide plate disposed so as to overlap a plurality of photodiodes and a light source that irradiates light onto a side surface of the light guide plate; 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, a reflective layer provided between the light guide plate and the optical filter layer and in a region overlapping the light-shielding portion of the optical filter layer; The reflective layer includes an inclined portion provided at an angle with respect to a surface of the light guide plate facing the optical filter layer, and a flat portion provided parallel to the surface of the light guide plate facing the optical filter layer. Detection device.

9. 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 area of ​​the flat portion in the first detection region is larger than the area of ​​the flat portion in the second detection region. The detection device according to claim 8.

10. The scattering portion is in the form of a dot or a prism. The detection device according to claim 1 .

11. The scattering portion is in the form of a dot or a prism. The detection device according to claim 4 .

12. The scattering portion is in the form of a dot or a prism. The detection device according to claim 5 .

Images