Detection Device

Abstract

Provided is a detection device (1) comprising a front light (FL) and having increased detection accuracy. The detection device (1) comprises: a front light (FL) comprising an optical sensor including a plurality of light-receiving elements (3) for receiving light, and a light source (LS) for irradiating a first side surface of a light guide plate (LG) with light; and an optical filter layer (50) provided between the light-receiving elements (3) and the front light (FL). When viewed from a detection surface (SF) of the light guide plate (LG) on the side of an object (FG) to be detected, a first opening (51b) of a light guide path (51) closest to the light-receiving elements (3) is displaced away from the light source (LS) more than a second opening (51a) of the light guide path (51) farthest from the light-receiving element (3). The light guide plate (LG) comprises on the side of the optical filter layer (50) a scattering portion (SC21) for scattering the light from the light source (LS). When viewed from a direction normal to the detection surface (SF) of the light guide plate (LG) on the side of the object (FG) to be detected, a first peak of the intensity of first light (SLu) emitted from the detection surface (SF) of the light guide plate (LG) is observed at an angle on the opposite side from the first side surface, rather than in the direction of the first side surface.

Description

[Technical Field]

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

[0002] In recent years, optical sensors have become known as sensors used for personal authentication and the like (for example, Patent Document 1). Optical sensors have a light-receiving element that outputs a signal that changes depending on the amount of light received. The sensor described in Patent Document 1 has a plurality of light-receiving elements, such as photodiodes, arranged on a substrate. Furthermore, in order for the light-receiving elements to receive an appropriate amount of light, illumination that illuminates the object to be detected is required. The object to be detected can be illuminated by placing a light guide plate on the front side of the light-receiving elements (for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

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

[0004] The optical detection devices described in Patent Documents 1 and 2 need to guide the light reflected from the subject to a light receiving element, but light that directly enters the light receiving element on the side opposite the subject leads to a decrease in contrast. There is room for improvement in optical detection devices in terms of guiding the light reflected from the subject to the light receiving element.

[0005] The present disclosure has been made in view of the above-mentioned problems, and aims to provide a detection device that is equipped with a front light and can further improve detection accuracy. [Means for solving the problem]

[0006] A detection device according to one embodiment of the present disclosure includes an optical sensor having a plurality of light-receiving elements that receive light; a front light disposed on the object-to-be-detected side of the optical sensor and including a light guide plate and a light source that irradiates light onto a first side of the light guide plate; and an optical filter layer provided between the light-receiving elements and the front light, wherein the optical filter layer includes a light guide path that at least partially overlaps the light-receiving elements and a light-shielding portion that has a higher light absorption rate than the light guide path, and when viewed from the detection surface of the light guide plate facing the object-to-be-detected, a first opening of the light guide path that is closest to the light-receiving elements is shifted in a direction away from the light source relative to a second opening of the light guide path that is farthest from the light-receiving elements, and the light guide plate includes a scattering portion on the optical filter layer side that scatters light from the light source, and when viewed from the normal direction of the detection surface of the light guide plate, a first peak of the intensity of the first light emitted from the detection surface of the light guide plate is observed to be tilted away from the first side surface rather than in the direction in which the first side surface is located. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a perspective view schematically illustrating a detection device according to the first embodiment. [Figure 2] FIG. 2 is a cross-sectional view schematically showing a cross section of the detection device according to the first embodiment. [Figure 3] FIG. 3 is a plan view schematically 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 light receiving element. [Figure 6] FIG. 6 is a plan view schematically showing a light receiving element of the detection device 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 schematically showing the positional relationship between the first opening and the second opening of the light guide path according to the first embodiment. [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 schematically showing a cross section of another detection device according to the first embodiment. [Figure 11] FIG. 11 is an explanatory diagram for explaining the relationship between the distribution of luminance from the light guide plate to the light receiving element and the distribution of luminance from the light guide plate to the detection object. [Figure 12] FIG. 12 is a perspective view schematically showing a detection device according to the second embodiment. [Figure 13] FIG. 13 is a cross-sectional view schematically showing a cross section of a first detection region of the detection device according to the second embodiment. [Figure 14] FIG. 14 is a cross-sectional view schematically showing a cross section of the second detection region of the detection device according to the second embodiment. [Figure 15] FIG. 15 is an explanatory diagram for explaining the relationship between the distribution of luminance from the light guide plate to the light receiving element and the distribution of luminance from the light guide plate to the detection object in the first detection region of the second embodiment. [Figure 16] FIG. 16 is an explanatory diagram for explaining the relationship between the distribution of luminance from the light guide plate to the light receiving element and the distribution of luminance from the light guide plate to the detection object in the second detection region of the second embodiment. [Figure 17] FIG. 17 is a cross-sectional view schematically illustrating a cross section of a second detection region of a detection device according to a first modification of the second embodiment. [Figure 18] FIG. 18 is an explanatory diagram for explaining the relationship between the distribution of luminance from the light guide plate to the light receiving element and the distribution of luminance from the light guide plate to the detection object in the second detection region of the first modification of the second embodiment. [Figure 19] FIG. 19 is a cross-sectional view schematically illustrating a cross section of a second detection region of a detection device according to Modification 2 of Embodiment 2. As shown in FIG. [Figure 20] FIG. 20 is a perspective view schematically showing a detection device according to the third embodiment. [Figure 21] FIG. 21 is a cross-sectional view schematically showing a cross section of the detection device according to the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] A mode for carrying out the invention (Embodiment 1) will be described in detail with reference to the drawings. The present disclosure is not limited to the content described in Embodiment 1 below. Furthermore, the components described below include those that a person skilled in the art would easily imagine 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 would easily conceive while maintaining the gist of the invention 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 specification and each drawing, elements similar to those previously described with reference to the preceding drawings may be designated by the same reference numerals, and detailed descriptions may be omitted as appropriate.

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

[0010] (Embodiment 1) FIG. 1 is a perspective view schematically showing a detection device according to a first embodiment. FIG. 2 is a cross-sectional view schematically showing a cross section of the detection device according to the first embodiment. As shown in FIG. 1, the detection device 1 has an optical sensor 5, an optical filter layer 50, and a front light FL. The front light FL has a translucent light guide plate LG and a light source LS facing a side surface of the light guide plate LG. 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 between the optical filter layer 50 and the front light FL.

[0011] The light source LS is, for example, a light emitting diode (LED) that emits red light or infrared light, but is not limited to this and can be changed appropriately to green or other colors depending on the measurement items. A plurality of LEDs of the light source LS are arranged along the side surface of the light guide plate LG.

[0012] As shown in FIG. 2 , the optical sensor 5 is located on the opposite side of the front light FL from the object to be detected. As viewed from the object to be detected FG, the optical sensor 5 overlaps the detection surface SF of the light guide plate LG. A scattering section SC11 is located on the opposite side of the detection surface SF of the light guide plate LG. The scattering section SC11 is a dot-shaped concave or convex portion. The scattering section SC11 may also be a groove. 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 toward the object to be detected FG. A portion of the light transmitted or reflected by the object to be detected FG returns to the light guide plate LG and is irradiated from the back surface of the light guide plate LG, opposite the detection surface SF. This allows the optical sensor 5 to detect information about the object to be detected FG using light irradiated from the light source LS.

[0013] As shown in FIG. 2, the optical sensor 5 includes a substrate 21 and a light-receiving element 3. The light-receiving element 3 detects light from a detection target FG. Specifically, when light from a light source LS reaches the detection target FG, the light is transmitted through or reflected by the detection target FG and enters the optical filter layer 50. The light passes through the optical filter layer 50 and enters the light-receiving element 3. This allows the optical sensor 5 to detect the light. The detection target FG may be, for example, a finger, a palm, or a wrist. For example, the optical sensor 5 can detect information such as a fingerprint of the detection target FG based on the light. The optical sensor 5 may also detect various information (biometric information), such as the shape of blood vessels, pulse rate, and pulse wave.

[0014] The optical filter layer 50 is an optical element that transmits, toward the photodiode 30, components of light reflected by a detectable object such as the detectable object FG that travel in a direction inclined in a predetermined direction with respect to the third direction Dz, and attenuates components that travel in other directions. The optical filter layer 50 is also called a collimator aperture or a collimator. The optical filter layer 50 is provided on the detectable object FG side of the light receiving element 3 and faces the light receiving element 3. The optical filter layer 50 has a plurality of light guide paths 51 and a light shielding portion 55 provided around the plurality of light guide paths 51.

[0015] Fig. 3 is a plan view schematically showing the detection device according to embodiment 1. As shown in Fig. 3, the optical sensor 5 includes a light receiving element array substrate 2 (substrate 21), a light receiving element 3, 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.

[0016] 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. A detection circuit 48 is provided on the wiring board 510. A control circuit 102 and a power supply circuit 103 are provided on the control board 501. 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 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. Note that, although the first embodiment illustrates a case in which the detection circuit 48 is disposed on the wiring board 510, the present invention is not limited to this. The detection circuit 48 may be disposed on the substrate 21.

[0017] The substrate 21 has a detection area AA and a peripheral area GA. The detection area AA is an area where a plurality of light receiving elements 3 of the sensor unit 10 are provided. The peripheral area GA is an area outside the detection area AA where no light receiving elements 3 are provided. In other words, the peripheral area GA is an area between the periphery of the detection area AA and the outer edge of the substrate 21.

[0018] Each of the light-receiving elements 3 of the sensor unit 10 is an optical sensor having a photodiode 30 as a sensor element. The photodiode 30 outputs an electrical signal corresponding to the light incident thereon. More specifically, the photodiode 30 is a PIN (Positive Intrinsic Negative) photodiode or an OPD (Organic Photodiode) using an organic semiconductor. The light-receiving elements 3 are arranged in a matrix in the detection area AA. The photodiodes 30 of the light-receiving elements 3 perform detection in accordance with a gate drive signal supplied from the scanning line drive circuit 15. The photodiodes 30 output an electrical signal corresponding to the light incident thereon as a detection signal Vdet to the signal line selection circuit 16. The detection device 1 detects information related to the object FG to be detected based on the detection signals Vdet from the photodiodes 30.

[0019] 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.

[0020] 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 with 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 substrate 21.

[0021] Fig. 4 is a block diagram showing an example of the configuration of the detection device according to embodiment 1. 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.

[0022] 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 and a clock signal CK, 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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 is a circuit that amplifies the detection signal Vdet, and is, for example, an integration circuit. The A / D conversion circuit 43 converts the analog signal output from the detection signal amplifier circuit 42 into a digital signal.

[0027] 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 the object to be detected FG comes into contact with or proximity to the detection surface SF (light guide plate LG), the signal processing circuit 44 can detect information based on light reflected by the object to be detected FG based on the signal from the detection circuit 48. The signal processing circuit 44 can also extract other biological information, such as a fingerprint, pulse wave, pulse rate, and blood oxygen saturation, based on the signal from the detection circuit 48.

[0028] 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.

[0029] The coordinate extraction circuit 45 is a logic circuit that determines the detection coordinates of the detectable object FG (for example, the detected positions of the unevenness on the surface of the finger or the detected positions of the blood vessels in the palm or wrist) when the signal processing circuit 44 detects contact or proximity of the detectable object FG. The coordinate extraction circuit 45 combines the detection signals Vdet output from each light receiving element 3 of the sensor unit 10 to generate two-dimensional information indicating the shape of the unevenness on the surface of the finger or an image of the blood vessels. Note that the coordinate extraction circuit 45 may output the detection signal Vdet as the sensor output Vo without calculating the detection coordinates.

[0030] Next, an example of the circuit configuration of the optical sensor 5 will be described. FIG. 5 is a circuit diagram showing a light receiving element of the optical sensor 5. As shown in FIG. 5, the light receiving 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 formed of a thin film transistor, and in this example, is formed of 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.

[0031] 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.

[0032] When light is irradiated onto the light receiving 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 light receiving element 3.

[0033] 5 shows one light receiving element 3, the scanning line GLS and the output signal line SLS are connected to a plurality of light receiving elements 3. Specifically, the scanning line GLS extends in a first direction Dx (see FIG. 2) and is connected to a plurality of light receiving 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 light receiving elements 3 arranged in the second direction Dy.

[0034] The first transistor Tr is not limited to an n-type TFT, and may be a p-type TFT. In addition, in the light receiving element 3, a plurality of transistors may be provided corresponding to one photodiode 30.

[0035] Next, a detailed configuration of the detection device 1 will be described. FIG. 6 is a plan view schematically showing a light receiving element of the detection device according to the first embodiment. As shown in FIG. 6, the light receiving element 3 is an area surrounded by the scanning line GLS and the output signal line SLS. In the first embodiment, the scanning line GLS includes 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.

[0036] The photodiode 30 is provided in a region surrounded by the scanning line GLS and the output signal line SLS. The photodiode 30 includes a semiconductor layer 31, an upper electrode 34, and a lower electrode 35. The photodiode 30 is, for example, a PIN photodiode.

[0037] 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 the first embodiment, the power supply signal line Lvs extends in the second direction Dy, overlapping with the output signal line SLS. The plurality of light receiving elements 3 arranged in the second direction Dy are connected to a common power supply signal line Lvs. This configuration allows the opening of the light receiving element 3 to be large. The lower electrode 35, the semiconductor layer 31, 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 semiconductor layer 31, and the upper electrode 34 can be changed as appropriate.

[0038] 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.

[0039] 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 light receiving 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.

[0040] 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.

[0041] 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.

[0042] The arrangement pitch of the light receiving 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 light receiving 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.

[0043] 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.

[0044] In the description of the optical sensor 5, the direction from the substrate 21 toward the photodiode 30 in the direction perpendicular to the surface of the substrate 21 (third direction Dz) 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." Furthermore, "plan view" refers to the positional relationship when viewed from the direction perpendicular to the surface of the substrate 21.

[0045] 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, first transistors Tr, various wirings (scanning lines GLS and output signal lines SLS), and an insulating layer are provided to form the light receiving element array substrate 2. The photodiodes 30 are arranged on the light receiving element 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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 the first 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.

[0050] 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.

[0051] 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 .

[0052] 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.

[0053] Next, the cross-sectional structure of the photodiode 30 will be described. The photodiode 30 is formed by stacking a lower electrode 35, a semiconductor layer 31, and an upper electrode 34 in this order on the first organic insulating layer 23a of the light-receiving element array substrate 2. The light-receiving element array substrate 2 is a drive circuit board that drives sensors for each predetermined detection area. The light-receiving element array substrate 2 has a substrate 21, and a first transistor Tr, a second transistor TrG, various wirings, etc., provided on the substrate 21.

[0054] 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).

[0055] The semiconductor layer 31 is made of amorphous silicon (a-Si). The semiconductor layer 31 includes an i-type semiconductor layer 32a, an n-type semiconductor layer 32b, and a p-type semiconductor layer 32c. The i-type semiconductor layer 32a, the n-type semiconductor layer 32b, and the p-type semiconductor layer 32c are a specific example of a photoelectric conversion element. In FIG. 7, the p-type semiconductor layer 32c, the i-type semiconductor layer 32a, and the n-type semiconductor layer 32b 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 32b, the i-type semiconductor layer 32a, and the p-type semiconductor layer 32c may also be used. The semiconductor layer 31 may also be a photoelectric conversion element made of an organic semiconductor.

[0056] The n-type semiconductor layer 32b is formed by doping impurities into a-Si to form an n+ region. The p-type semiconductor layer 32c is formed by doping impurities into a-Si to form a p+ region. The i-type semiconductor layer 32a is, for example, an undoped intrinsic semiconductor and has lower conductivity than the n-type semiconductor layer 32b and the p-type semiconductor layer 32c.

[0057] 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.

[0058] 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 connection 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 connection 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, insulating layer 22h may be further provided thereon.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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).

[0065] 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.

[0066] 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.

[0067] FIG. 8 is a plan view schematically showing the positional relationship between the first opening and the second opening of the light guide path according to the first embodiment.

[0068] 8 is a partially enlarged plan view of a part of the optical filter layer 50 as viewed from the third direction Dz (the light guide plate LG side), and the position of the second opening 51a of the light guide path 51 relative to the light receiving element 3 in plan view is indicated by a dotted line. In the first embodiment, the first opening 51b and the second opening 51a have the same area in plan view.

[0069] As shown in FIG. 8, the optical filter layer 50 has a plurality of light guide paths 51 and a light blocking portion 55. The plurality of light guide paths 51 are arranged in a matrix in a first direction Dx and a second direction Dy. Each of the plurality of light guide paths 51 is capable of transmitting light (see FIG. 2). The light blocking portion 55 has a higher light absorptance than 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.

[0070] The light-shielding 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-shielding 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 the incident light in and the intensity of the outgoing light out to the intensity of the incident light in.

[0071] 8 are located on the second surface that emits light to the light receiving elements 3. As shown in Fig. 8, each of the second openings 51a is disposed offset from the first openings 51b in the first direction Dx. The first openings 51b of the multiple light guide paths 51 are disposed to overlap the light receiving elements 3, allowing light to be emitted to the light receiving elements 3 with high precision.

[0072] 2 and 8, the optical filter layer 50 has a surface on which the second opening 51a is located and a surface on which the first opening 51b is located opposite to the surface on which the second opening 51a is located. As shown in FIG. 8, the first opening 51b of the optical filter layer 50 faces the light receiving element 3.

[0073] FIG. 9 is a cross-sectional view schematically illustrating a cross section of a detection device according to a comparative example. The light guide 51 of the comparative example is parallel to the third direction Dz. In the light guide according to the comparative example, light reflected by the object FG and other external light easily reach the light receiving element 3. In contrast, in the first embodiment, the first opening 51b of the light guide 51 closest to the photodiode 30 of the light receiving element 3 overlaps with the photodiode 30 of the light receiving element 3 as viewed from the third direction Dz, and the second opening 51a of the light guide 51 farthest from the photodiode 30 of the light receiving element 3 is shifted in the first direction Dx from the first opening 51b. This allows light reflected by the object FG to be selected and easily reach the light receiving element 3. As a result, noise in the photodiode 30 is reduced, and sensing sensitivity is improved. It is more preferable that the second opening 51a of the light guide 51 does not overlap with the first opening 51b.

[0074] Fig. 10 is a cross-sectional view schematically illustrating a cross section of another detection device according to the first embodiment. Fig. 11 is an explanatory diagram illustrating the relationship between the luminance distribution from the light guide plate to the light receiving element and the luminance distribution from the light guide plate to the object to be detected. The scattering section SC11 described above scatters light isotropically. As a result, some light enters the light guide path 51 from the light guide plate LG, which may reduce the contrast of the light detected by the light receiving element 3.

[0075] 10, in the first embodiment, the scattering portion SC21 has a triangular recess or protrusion in a cross-sectional view. A plurality of scattering portions SC21 are arranged, and a back-exit surface SC22 parallel to the detection surface SF is provided between adjacent scattering portions SC21. The back-exit surface SC22 and the second opening 51a are arranged to be aligned on an extension of the direction in which the light guide path 51 extends.

[0076] Fig. 11 is an explanatory diagram illustrating the relationship between the distribution of luminance from the light guide plate to the light receiving element and the distribution of luminance from the light guide plate to the detected object. In the detection device 1 shown in Fig. 10, as shown in Fig. 11, in the first light SLu having a first peak and a first distribution that is emitted from the detection surface SF of the light guide plate LG toward the detected object FG, the first peak is observed tilted at an angle θ1 with respect to the normal direction of the detection surface SF. As shown in Fig. 10, the first peak of the intensity of the first light SLu is observed tilted in the opposite direction to the direction of the side surface of the light guide plate LG where the light source LS is located.

[0077] 11, in the second light Stu having the second peak and the second distribution emitted from the back exit surface SC22, the second peak is observed in the opposite direction to the direction in which the first peak of the intensity of the first light SLu is observed with respect to the third direction Dz shown in Fig. 10. The second peak of the intensity of the second light Stu is observed at an angle −θ1 with respect to the normal direction of the detection surface SF.

[0078] The multiple light guides 51, also called light guide columns, each extend from the first surface, where the first opening 51b is located, to the second surface, where the second opening 51a is located, at an angle θ1 with respect to the third direction Dz. That is, the second openings 51a of the multiple light guides 51 are offset in the first direction Dx from the first openings 51b of the optical filter layer 50. As a result, as shown in FIG. 11 , the light receiving element 3 detects the third light Ssu, which has a third peak and a third distribution narrower than the second distribution of the second light Stu, thereby improving detection accuracy. The angle between the third direction and the direction in which the light guides extend is preferably equal to the angle between the third direction and the direction in which the first peak of the intensity of the first light SLu emitted from the detection surface SF of the light guide plate LG is observed. This improves the detection sensitivity of the light receiving element 3.

[0079] (Embodiment 2) FIG. 12 is a perspective view schematically showing a detection device according to embodiment 2. FIG. 13 is a cross-sectional view schematically showing a cross section of a first detection region of the detection device according to embodiment 2. FIG. 14 is a cross-sectional view schematically showing a cross section of a second detection region of the detection device according to embodiment 2. FIG. 15 is an explanatory diagram for explaining the relationship between the luminance distribution from the light guide plate to the light receiving element and the luminance distribution from the light guide plate to the object to be detected in the first detection region of embodiment 2. FIG. 16 is an explanatory diagram for explaining the relationship between the luminance distribution from the light guide plate to the light receiving element and the luminance distribution from the light guide plate to the object to be detected in the second detection region of embodiment 2. The same structures as those in embodiment 1 are assigned the same reference numerals, and detailed explanations will be omitted.

[0080] 12, the detection surface SF has a first detection region AA1 and a second detection region AA2 in order of proximity to the light source LS. By providing the scattering section SC21, the first peak intensity SLu is observed tilted in the opposite direction to the direction of the side surface of the light guide plate LG where the light source LS is located. From the propagation characteristics of light within the light guide plate LG, it was found that the tilt of the first light with respect to the third direction Dz increases with increasing distance from the light source LS.

[0081] For example, as shown in FIG. 13 , in the cross section of the first detection area AA1, the scattering portions SC31 are triangular recesses or protrusions in a cross section. A plurality of scattering portions SC31 are arranged, and a back-exit surface SC32 parallel to the detection surface SF is provided between adjacent scattering portions SC31. The back-exit surface SC32 and the second opening 51a are arranged to be aligned on an extension of the direction in which the light guide path 51 extends. As shown in FIG. 15 , the first light SLu1 having a first peak and a first distribution that is emitted from the detection surface SF of the light guide plate LG toward the object FG is observed at an angle θ1 with respect to the normal to the detection surface SF. The second light Stu1 having a second peak and a second distribution that is emitted from the back-exit surface SC32 has a second peak that is observed in the opposite direction to the third direction Dz from the direction in which the first peak is observed. 15, the first peak of the intensity of the first light SLu1 is observed tilted in the opposite direction to the side of the light guide plate LG where the light source LS is located. The light receiving element 3 detects the third light Ssu1 having a third peak and a third distribution that is narrower than the second distribution of the second peak light Stu1, thereby improving detection accuracy.

[0082] For example, as shown in FIG. 14, in the cross section of the second detection area AA2, the scattering portions SC33 are triangular recesses or protrusions in a cross section. A plurality of scattering portions SC33 are arranged, and a back-exit surface SC34 parallel to the detection surface SF is provided between adjacent scattering portions SC33. The back-exit surface SC34 and the second opening 51a are arranged to be aligned on an extension of the direction in which the light guide path 51 extends. The number of scattering portions SC33 overlapping the second detection area AA2 is greater than the number of scattering portions SC31 overlapping the first detection area AA1. As shown in FIG. 16, the first light SLu2 having a first peak and a first distribution, which is emitted from the detection surface SF of the light guide plate LG toward the detected object FG, is observed at an angle θ2 with respect to the normal to the detection surface SF. The second light Stu2, which has a second peak and a second distribution and is emitted from the rear exit surface SC32, is observed in the direction opposite to the direction in which the first peak is observed with respect to the third direction Dz. As shown in FIG. 16 , the first peak of the intensity of the first light SLu2 is observed tilted in the opposite direction to the direction of the side surface of the light guide plate LG where the light source LS is located. The light receiving element 3 detects the third light Ssu2, which has a third peak and a third distribution that is narrower than the second distribution of the second light Stu2, thereby improving detection accuracy. The intensity of the first peak of the first light SLu2 is smaller than the intensity of the first peak of the first light SLu1.

[0083] Therefore, in the second embodiment, the second angle θ2 formed between the third direction Dz and the extension direction of the light guide 51 overlapping with the second detection region AA2 is set larger than the first angle θ1 formed between the third direction Dz and the extension direction of the light guide 51 overlapping with the first detection region AA1. This increases the amount of light passing through the light guide 51, and suppresses in-plane variations in the detection value on the detection surface SF.

[0084] The above has been described using the first detection area AA1 and the second detection area AA2 as examples, but the angle formed between the third direction Dz and the direction in which the light guide path 51 extends may be configured to increase in order as the distance from the light source LS increases.

[0085] (Modification 1 of Embodiment 2) 17 is a cross-sectional view schematically showing a cross section of the second detection region of the detection device according to Modification 1 of Embodiment 2. The same structures as those in Embodiments 1 and 2 are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0086] The first detection region AA1 is the same as in the second embodiment, and therefore its description will be omitted. For example, as shown in FIG. 17, in the cross section of the second detection region AA2, the scattering portions SC35 are triangular concave or convex portions in a cross section. A plurality of scattering portions SC35 are arranged, and a back-exit surface SC36 parallel to the detection surface SF is provided between adjacent scattering portions SC35. The back-exit surface SC36 and the second opening 51a are arranged so as to be aligned on an extension line of the light guide path 51. The number of scattering portions SC35 overlapping the second detection region AA2 is greater than the number of scattering portions SC31 overlapping the first detection region AA1. The number of scattering portions SC35 overlapping the second detection region AA2 is greater than the number of scattering portions SC33 overlapping the second detection region AA2 shown in FIG. 14. This increases the amount of light scattered by the scattering portions SC35.

[0087] As shown in FIG. 18, the first light SLu3, which has a first peak and a first distribution and is emitted from the detection surface SF of the light guide plate LG toward the object FG, is observed at an angle θ2 with respect to the normal to the detection surface SF. The second light Stu3, which has a second peak and a second distribution and is emitted from the rear emission surface SC36, is observed in the direction opposite to the direction in which the first peak is observed with respect to the third direction Dz. As shown in FIG. 18, the first peak of the intensity of the first light SLu3 is observed at an angle opposite to the direction of the side surface of the light guide plate LG where the light source LS is located. The light receiving element 3 detects the third light Ssu3, which has a third peak and a third distribution that is narrower than the second distribution of the second light Stu3, thereby improving detection accuracy. The intensity of the first peak of the first light SLu3 is approximately the same as the intensity of the first peak of the first light SLu1. This makes the detection sensitivity of the third light Ssu1 and the detection sensitivity of the third light Ssu3 approximately the same.

[0088] Although the first detection area AA1 and the second detection area AA2 have been described above as examples, the number of scattering portions may increase in order as the area becomes farther from the light source LS.

[0089] (Modification 2 of Embodiment 2) 19 is a cross-sectional view schematically illustrating a cross section of the second detection region of a detection device according to Modification 2 of Embodiment 2. The same structures as those of Embodiment 1, Embodiment 2, and Modification 1 of Embodiment 2 are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0090] The first detection region AA1 is the same as in the second embodiment, and therefore description thereof will be omitted. As shown in Fig. 19, the transmittance of the optical filter layer 50 overlapping with the second detection region AA2 is greater than the transmittance of the optical filter layer 50 overlapping with the first detection region AA1. For example, when viewed from the third direction Dz, the area of ​​the Dx-Dy cross section of the light guide path 51 overlapping with the second detection region AA2 (see Fig. 19) is made greater than the area of ​​the light guide path 51 overlapping with the first detection region AA1 (see Fig. 13).

[0091] Modification 2 of Embodiment 2 has the same effects as Modification 1 of Embodiment 2. Although the first detection area AA1 and the second detection area AA2 have been described above as examples, the transmittance of the optical filter layer 50 may be configured to increase in order with increasing distance from the light source LS.

[0092] (Embodiment 3) Fig. 20 is a perspective view schematically showing a detection device according to embodiment 3. Fig. 21 is a cross-sectional view schematically showing a cross section of a detection device according to embodiment 3. The same structures as those in embodiment 1, embodiment 2, and the modified example of embodiment 2 are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0093] 20, in the detecting device 1 according to the third embodiment, the light guide plate LG is curved. The light receiving element array substrate 2 (substrate 21) is made of resin and is a flexible substrate. The flexible light receiving element array substrate 2 (substrate 21) is curved along the curvature of the light guide plate LG.

[0094] The object to be detected FG is, for example, an arm or a leg, and the front light FL can be pressed against the object to be detected FG along the shape of the object to be detected FG.

[0095] As shown in Figure 21, the flexible light-receiving element array substrate 2 (substrate 21) is curved along the curvature of the light guide plate LG, so that the radius of curvature of the light guide plate LG around the virtual center Ax is approximately the same as the radius of curvature of the flexible light-receiving element array substrate 2 (substrate 21).

[0096] The scattering portion SC41 has a triangular recess or protrusion in a cross-sectional view. A plurality of scattering portions SC41 are arranged, and a back exit surface SC42 that is curved similarly to the detection surface SF is provided between adjacent scattering portions SC41. The back exit surface SC42 and the second opening 51a are arranged to be aligned on an extension of the direction in which the light guide path 51 extends.

[0097] Although preferred embodiments of the present disclosure have been described above, the present disclosure is not limited to such embodiments. The contents disclosed in the embodiments are merely examples, and various modifications are possible within the scope of the present disclosure. Appropriate modifications made within the scope of the present disclosure also naturally fall within the technical scope of the present disclosure.

[0098] For example, in this embodiment, an example has been described in which the direction in which the second opening 51a is shifted relative to the first opening 51b is the first direction Dx, but the direction in which the second opening 51a is shifted relative to the first opening 51b may be any direction in the Dx-Dy plane.

[0099] The optical filter layer 50 may have a pinhole shape in which the light-shielding portions 55 are intermittent in the thickness direction and the light guide paths 51 are scattered. Also, the light guide paths 51 may be overlapped with microlenses. [Explanation of symbols]

[0100] 1. Detection device 2. Photodetector array substrate 3 Photodetector 5 Optical Sensor 10 Sensor section 21 PCB 30 Photodiode 50 optical filter layer 51 Light guide 51a 2nd opening 51b 1st opening 55 Light blocking section AA1 First detection area AA2 Second detection area Dx 1st direction Dy 2nd direction Dz Third direction FL Front Light FG Object to be detected LG light guide plate LS light source SC11, SC21, SC31, SC33, SC35, SC41 Scatter part SC22, SC32, SC34, SC36, SC42 Back exit surface SF detection surface

Claims

1. an optical sensor having a plurality of light receiving elements that receive light; a front light disposed on the detection object side of the optical sensor and including a light guide plate and a light source that irradiates light onto a first side surface of the light guide plate; an optical filter layer provided between the light receiving element and the front light, the optical filter layer includes a light guide path at least partially overlapping the light receiving element, and a light blocking portion having a higher light absorption rate than the light guide path; When viewed from a detection surface of the light guide plate on the detection object side, a first opening of the light guide path that is closest to the light receiving element is shifted in a direction away from the light source with respect to a second opening of the light guide path that is farthest from the light receiving element, the light guide plate includes a scattering portion on the optical filter layer side that scatters light from the light source, a first peak of intensity of the first light emitted from the detection surface of the light guide plate is observed tilted toward a side opposite to the first side surface with respect to a direction normal to the detection surface of the light guide plate, a plurality of the scattering sections are arranged, and a back exit surface is provided between the scattering sections, the back exit surface being parallel to the detection surface; the rear exit surface and the second opening are arranged to be aligned on an extension line of the light guide path, the scattering portion and the second opening are not arranged to be aligned on an extension line of the light guide path, the second opening is offset from the rear light exit surface in a direction away from the light source, the scattering portion has a triangular shape in cross section, an angle formed between the normal direction and a direction in which a first peak of the intensity of the first light is observed is opposite to an angle formed between the normal direction and a direction in which a second peak of the intensity of the second light emitted from the light guide plate to a back surface opposite to the detection surface is observed; Detection device.

2. 2. The detection device according to claim 1, wherein an angle formed between the normal direction and a direction in which a first peak of the intensity of the first light is observed is equal to an angle formed between the normal direction and an extension direction of the light guide path.

3. a first detection area of ​​the light guide plate and a second detection area that is farther from the light source than the first detection area when viewed from the normal direction; the angle formed between the normal direction and the extending direction of the light guide path varies depending on the location of the light guide path, 2. The detection device according to claim 1, wherein a second angle formed between the normal direction and the extension direction of the light guide path overlapping with the second detection region is larger than a first angle formed between the normal direction and the extension direction of the light guide path overlapping with the first detection region.

4. a first detection area of ​​the light guide plate and a second detection area that is farther from the light source than the first detection area when viewed from the normal direction; The detection device according to claim 1 , wherein a transmittance of an optical filter layer overlapping the second detection region is greater than a transmittance of an optical filter layer overlapping the first detection region.

5. a first detection area of ​​the light guide plate and a second detection area that is farther from the light source than the first detection area when viewed from a normal direction of the light guide plate; The detection device according to claim 1 , wherein an area of ​​the light guide path overlapping with the second detection region is larger than an area of ​​the light guide path overlapping with the first detection region when viewed from the normal direction.

6. a first detection area of ​​the light guide plate and a second detection area that is farther from the light source than the first detection area when viewed from a normal direction of the light guide plate; The detection device according to claim 1 , wherein the number of scattering portions overlapping with the second detection region is greater than the number of scattering portions overlapping with the first detection region when viewed from the normal direction.

7. the plurality of light receiving elements are provided on a flexible substrate; the light guide plate is curved, The detection device according to claim 1 , wherein the flexible substrate is curved in accordance with the curvature of the light guide plate.

Images