Detection device

Abstract

The present invention provides a detection device that makes it possible to obtain better detection accuracy by uniformly irradiating the entire surface of an optical sensor surface with light. This detection device comprises: an optical sensor having a plurality of light-receiving elements that receive light; and a front light that is disposed on a detection-target side of the optical sensor and that comprises a light guide film and a plurality of light sources that irradiate a first side surface of the light guide film with light. A wire grid polarizer, which separates light incident from the light sources into first polarized light and second polarized light, is disposed between the optical sensor and the front light.

Description

Detection device

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

[0002] Optical sensors capable of detecting fingerprint patterns and vein patterns are known (for example, see 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.

[0003] JP2019-045503A JP11-120324A

[0004] When such a detection device is used on thick skin such as the wrist, the light receiving elements near the center of the optical sensor, which are far from the light source, may receive insufficient light, which may reduce the detection contrast.

[0005] An object of the present invention is to provide a detection device that can uniformly irradiate the entire optical sensor surface with light and achieve better detection accuracy.

[0006] A detection device according to one embodiment of the present disclosure comprises an optical sensor having a plurality of light receiving elements that receive light, and a front light arranged on the object-to-be-detected side of the optical sensor and including a light-guiding film and a plurality of light sources that irradiate a first side of the light-guiding film with light, and a wire-grid polarizer arranged between the optical sensor and the front light that separates the light incident from the light sources into a first polarization and a second polarization.

[0007] FIG. 1 is a perspective view schematically showing a detection device according to Embodiment 1. FIG. 2 is a cross-sectional view schematically showing a cross section of the detection device according to Embodiment 1. FIG. 3 is an explanatory diagram showing transmittance versus acceptance angle of the optical filter layer according to Embodiment 1. FIG. 4A is a side view schematically showing a wire grid polarizer according to Embodiment 1. FIG. 4B is a side view schematically showing a wire grid polarizer having a wire direction different from that of FIG. 4A. FIG. 5 is a plan view schematically showing a detection device according to Embodiment 1. FIG. 6 is a block diagram showing an example configuration of the detection device according to Embodiment 1. FIG. 7 is a circuit diagram showing a light receiving element. FIG. 8 is a plan view schematically showing a light receiving element of the detection device according to Embodiment 1. FIG. 9 is a cross-sectional view taken along the line IX-IX′ of FIG. 8. FIG. 10 is an explanatory diagram showing the relationship between the incidence dependency of the transmittance of the light guiding film and the incidence dependency of the reflectance of the wire grid polarizer according to Embodiment 1. FIG. 11 is a cross-sectional view schematically showing a cross section of a detection device according to Embodiment 2. FIG. 12 is an explanatory diagram showing the relationship between the incidence dependency of the transmittance of the light guiding film and the incidence dependency of the reflectance of the wire grid polarizer in embodiment 2. FIG. 13 is a perspective view schematically showing an example of a detection device according to embodiment 3. FIG. 14 is a perspective view schematically showing an example different from the detection device of FIG. 13. FIG. 15 is a perspective view schematically showing an example different from the detection device of FIG. 14. FIG. 16 is a plan view schematically showing a detection device according to embodiment 4. FIG. 17 is a perspective view schematically showing a detection device according to embodiment 5. FIG. 18 is a cross-sectional view schematically showing a cross section of a detection device according to embodiment 6. FIG. 19 is a perspective view schematically showing a detection device according to embodiment 6. FIG. 20 is a cross-sectional view schematically showing a cross section of a detection device according to embodiment 7. FIG. 21 is a plan view schematically showing a detection device according to embodiment 7. FIG. 22 is an explanatory diagram showing the transmittance of a high-refractive-index waveguide layer with respect to the angle of incidence in embodiment 7. FIG. 23 is a plan view schematically showing a detection device according to embodiment 8. Fig. 24 is an explanatory diagram showing the transmittance of a light guiding film with respect to the angle of incidence in embodiment 8. Fig. 25 is a cross-sectional view schematically showing an example of a light receiving element according to embodiment 8. Fig. 26 is a cross-sectional view schematically showing an example different from the light receiving element in Fig. 25 .FIG. 27 is a cross-sectional view schematically showing an example different from the light receiving element of FIG. 26 . FIG. 28 is a cross-sectional view schematically showing a cross section of a detection device according to embodiment 9. FIG. 29 is an explanatory diagram illustrating the transmittance of a light guiding film with respect to the angle of incidence in embodiment 9. FIG. 30 is an explanatory diagram illustrating the transmittance of a light guiding film with respect to the angle of incidence, different from the detection device of FIG. 29 . FIG. 31 is a plan view schematically showing a detection device according to embodiment 10. FIG. 32 is an explanatory diagram showing the relationship between the transmittance of a light guiding film with respect to the angle of incidence and the transmittance of a protective film with respect to the angle of incidence in embodiment 10. FIG. 33 is a plan view schematically showing a detection device according to embodiment 11. FIG. 34 is a perspective view schematically showing a detection device according to embodiment 12.

[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 or 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 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 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 Embodiment 1. Fig. 2 is a cross-sectional view schematically showing a cross section of the detection device according to Embodiment 1. Fig. 3 is an explanatory diagram showing transmittance versus acceptance angle of the optical filter layer according to Embodiment 1. Fig. 4A is a side view schematically showing a wire grid polarizer according to Embodiment 1. Fig. 4B is a side view schematically showing a wire grid polarizer having a wire direction different from that of Fig. 4A. As shown in Figs. 1 and 2, the detection device 1 includes an optical sensor 5, an optical filter layer 50, a wire grid polarizer WG, and a front light FL. The optical filter layer 50, the wire grid polarizer, and the front light FL are stacked in this order on the optical sensor 5.

[0011] The front light FL has a light guide film LG and a light source LS facing a side surface of the light guide film LG. The front light FL is disposed on the detection object FG side of the optical sensor 5, and includes the light guide film LG, a reflector FL1, a light entrance part LG1, and multiple light sources LS. The detection object FG is, for example, a palm, a wrist, or a finger.

[0012] The plurality of light sources LS are arranged along one side surface of the light guiding film LG. Each of the plurality of light sources LS emits light onto a first side surface of the light guiding film LG through a light entrance portion LG1. For example, an inorganic LED (LED: Light Emitting Diode), an organic EL (OLED: Organic Light Emitting Diode), a semiconductor laser LD (LD: Laser Diode), or the like is used as each of the plurality of light sources LS. The light source 60 emits light of a predetermined wavelength. In this embodiment, the light source LS has a plurality of light sources capable of emitting infrared light, near-infrared light, red light, and visible light ranging from green light to blue light.

[0013] The reflector FL1 is disposed on the side of the light guide film LG opposite the light source LS or on the side where the light source LS is not provided. The reflector FL1 reflects the light L propagating through the light guide film LG toward the side on the light source LS side.

[0014] The light entrance portion LG1 is a base material provided to efficiently guide the light emitted from the light source LS into the light guide film LG. The light entrance portion LG1 is light-transmitting and is made of, for example, an optical resin.

[0015] 2, the optical sensor 5 includes a substrate 21 and a light receiving element 3. The optical sensor 5 is located on the opposite side of the front light FL from the side of the object to be detected, and the optical sensor 5 overlaps the detection surface SF of the light guide film LG when viewed from the side of the object to be detected FG of the light guide film LG.

[0016] The light guide film LG is a light-transmitting film made of a polymer compound such as TAC (Triacetylcellulose).

[0017] The refractive index of the light guide film LG is, for example, 1.487. The refractive index of the epidermis of the detection object FG is, for example, 1.43. The refractive index of the dermis of the detection object FG is, for example, 1.396.

[0018] The size of the light guide film LG is, for example, 50 μm to 300 μm.

[0019] 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 to it. 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.

[0020] The optical filter layer 50 is disposed between the light receiving element 3 and the wire grid polarizer WG. The optical filter layer 50 is an optical element that transmits, toward the photodiode 30, components of light reflected by the object to be detected FG or the like that travel in the third direction Dz and attenuates components that travel in other directions. The optical filter layer 50 is also called a collimator aperture or collimator. The optical filter layer 50 is provided on the object to be detected 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. At least a portion of the light guide paths 51 overlaps the photodiode 30. The light shielding portion 55 has a higher light absorption rate than the light guide paths 51.

[0021] The optical filter layer 50 and the optical sensor 5 are bonded together with an optical resin (not shown). A space may be provided between the optical filter layer 50 and the optical sensor 5.

[0022] 3, the narrower the acceptance angle at which light is accepted by the optical filter layer 50, the higher the imaging resolution becomes. This makes it possible to capture images of fingerprints, etc. The acceptance angle of the optical filter layer 50 is the angle at which light enters the optical filter layer 50.

[0023] As shown in FIGS. 1 and 2, the wire grid polarizer WG is disposed between the optical filter layer 50 and the front light FL.

[0024] 1 and 4A , the wire grid polarizer WG includes a plurality of wire grid polarizers WG1 and a light guiding film supporting the wire grid polarizers WG1. The plurality of wire grid polarizers WG1 are arranged on the light guiding film LG at predetermined intervals in the first direction Dx, extend along the second direction Dy, and protrude toward the optical sensor 5 in the third direction Dz.

[0025] The wire grid polarizer WG1 is formed of a wire grid using metal nanowires, and is made of a material such as an aluminum alloy.

[0026] As shown in FIG. 4A , the wire grid polarizer WG1 separates light L incident from a light source LS into a first polarized light component L1 and a second polarized light component L2. When light L is incident from a direction perpendicular to the wire grid polarizer WG1 (a direction perpendicular to the second direction Dy), the first polarized light component L1, which vibrates parallel to the wire direction of the wire grid polarizer WG1, is reflected by the wire grid polarizer WG1, while the second polarized light component L2, which vibrates perpendicular to the wire direction of the wire grid polarizer WG1, is transmitted through the wire grid polarizer WG1. Here, the wire direction refers to the direction in which the wires of the wire grid polarizer WG1 extend. In this embodiment, the first polarized light component L1 is an s-polarized component, and the second polarized light component L2 is a p-polarized component. Note that depending on the incident direction of light L, the first polarized light component L1 may be a p-polarized component and the second polarized light component L2 may be an s-polarized component.

[0027] The wire direction of the wire grid polarizer WG1 can be not only the first direction Dx shown in FIG. 4A but also the second direction Dy shown in FIG. 4B.

[0028] 4B , when light L is incident from a direction parallel to the wire grid polarizer WG1 (a direction parallel to the second direction Dy), the wire grid polarizer WG1 reflects the first polarized light L1 and transmits the second polarized light L2, which then exits toward the light-receiving element 3. Thus, regardless of the incident direction of light L, the first polarized light L1, which vibrates parallel to the wire direction of the wire grid polarizer WG1, is always reflected by the wire grid polarizer WG1, and the second polarized light L2, which vibrates perpendicular to the wire direction of the wire grid polarizer WG1, is transmitted through the wire grid polarizer WG1. In this case, the light guiding film LG propagates the first polarized light L1 and transmits the second polarized light L2, which then exits toward the light-receiving element 3.

[0029] A gap GP is provided between the wire grid polarizer WG and the optical filter layer 50. The gap GP is bonded with, for example, an optical resin (not shown). The gap GP may be, for example, an air layer.

[0030] As shown in FIG. 2 , light from a light source LS is irradiated into the light-guiding film LG. The first polarized light L1 reflected by the wire grid polarizer WG1 propagates through the light-guiding film LG. When a subject FG comes into contact with the detection surface SF, the first polarized light L1 reaches the epidermis of the subject FG. The second polarized light L2 transmitted through the wire grid polarizer WG1 is blocked from reaching the light-receiving element 3 when the optical filter layer 50 has an acceptance angle of approximately 20° or greater (see FIG. 3 ). However, when the optical filter layer 50 has an acceptance angle of approximately 20° or less (see FIG. 3 ), the second polarized light L2 passes through the optical filter layer 50 and enters the light-receiving element 3. This allows the optical sensor 5 to detect light. The optical sensor 5 can detect information about the skin of the subject FG, for example, based on the light irradiated from the light source LS. The optical sensor 5 may also detect various information (biometric information), such as blood vessel shape, pulse rate, and pulse wave.

[0031] Furthermore, when the first polarized light L1 reaches a measurement site (e.g., a blood vessel) deep in the dermis, it becomes backscattered light L3 and is depolarized. When the backscattered light L3 from the measurement site is incident on the wire grid polarizer WG1, the second polarized light L2 component is transmitted through the wire grid polarizer WG1. At this time, the acceptance angle of the optical filter layer 50 is approximately 20° or less, and the second polarized light L2 enters the optical filter layer 50 side, passing through the optical filter layer 50 and entering the light receiving element 3.

[0032] As a result of the above, by performing good polarization separation, the amount of light leaking from the light-guiding film LG is reduced, and the first polarized light L1 can be uniformly irradiated onto the entire surface of the object FG side of the optical sensor 5, resulting in better detection accuracy.

[0033] Fig. 5 is a plan view schematically illustrating the detection device according to embodiment 1. As shown in Fig. 5, the optical sensor 5 includes an 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.

[0034] The 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 detection circuit 48 is provided on the wiring board 510. 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 power supply circuit 103 supplies voltage signals such as a power supply potential SVS and a reference potential VR1 (see FIG. 7 ) 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 provided on the wiring board 510, the present invention is not limited to this. The detection circuit 48 may be provided on the substrate 21.

[0035] 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 the light receiving elements 3 are not 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.

[0036] 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 irradiated thereon. Specifically, the photodiode 30 is a PIN (Positive Intrinsic Negative) photodiode or an organic photodiode (OPD) 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 irradiated thereon as a detection signal Vdet to the signal line selection circuit 16. The detection device 1 detects information related to the object FG based on the detection signals Vdet from the photodiodes 30.

[0037] 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.

[0038] Fig. 6 is a block diagram showing an example of the configuration of the detection device according to embodiment 1. As shown in Fig. 6, 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.

[0039] 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.

[0040] The scanning line driving circuit 15 is a circuit that drives a plurality of scanning lines GLS (see FIG. 7 ) based on various control signals. The scanning line driving circuit 15 sequentially or simultaneously selects the plurality of scanning lines GLS and supplies a gate driving signal VGL to the selected scanning lines GLS. In this way, the scanning line driving circuit 15 selects a plurality of photodiodes 30 connected to the scanning lines GLS.

[0041] The signal line selection circuit 16 is a switch circuit that sequentially or simultaneously selects a plurality of output signal lines SLS (see FIG. 7 ). 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.

[0042] 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. The detection timing control circuit 47 controls the detection circuit 48, the signal processing circuit 44, and the coordinate extraction circuit 45 based on a control signal supplied from the detection control circuit 11 so that they operate in synchronization with each other.

[0043] The detection circuit 48 is, for example, an analog front end (AFE) circuit. The detection circuit 48 is a signal processing circuit that has 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.

[0044] 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 detection object FG comes into contact with or proximity to the detection surface SF, the signal processing circuit 44 can detect information based on light reflected by the detection object FG based on the signal from the detection circuit 48. The signal processing circuit 44 can also extract other biological information, such as pulse wave, pulse rate, and blood oxygen saturation, based on the signal from the detection circuit 48.

[0045] 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.

[0046] The coordinate extraction circuit 45 is a logic circuit that calculates the detection coordinates of the detectable object FG (for example, the detected position of blood vessels in the palm or wrist) when contact with or proximity of the detectable object FG is detected by the signal processing circuit 44. 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 of the skin surface and 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.

[0047] Next, an example of the circuit configuration of the optical sensor 5 will be described. FIG. 7 is a circuit diagram showing a light receiving element of the optical sensor 5. As shown in FIG. 7, 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 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.

[0048] 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.

[0049] 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.

[0050] 7 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.

[0051] 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.

[0052] Next, the detailed configuration of the detection device 1 will be described. FIG. 8 is a plan view schematically illustrating a light receiving element of the detection device according to the first embodiment. As shown in FIG. 8, the light receiving element 3 is an area surrounded by scanning lines GLS and output signal lines SLS. In this embodiment, the scanning lines GLS include a first scanning line GLA and a second scanning line GWG1. The first scanning line GLA is arranged to overlap the second scanning line GWG1. The first scanning line GLA and the second scanning line GWG1 are arranged in different layers with insulating layers 22c and 22d (see FIG. 9) interposed therebetween. The first scanning line GLA and the second scanning line GWG1 are electrically connected at an arbitrary location 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 GWG1 is connected to a scanning line drive circuit 15. In FIG. 8, the first scanning line GLA and the second scanning line GWG1 have different widths, but they may have the same width.

[0053] The photodiode 30 is provided in a region surrounded by the scanning lines GLS and the output signal lines 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.

[0054] The upper electrode 34 is connected to a 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.

[0055] 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.

[0056] 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. Therefore, the detection device 1 can improve the S / N ratio. However, the semiconductor layer 61 is not limited thereto and may be a microcrystalline oxide semiconductor, an amorphous oxide semiconductor, polysilicon, low-temperature polycrystalline silicon (LTPS), or the like.

[0057] The semiconductor layer 61 is disposed 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 disposed branching off from the first scanning line GLA and the second scanning line GWG1, respectively. In other words, portions of the first scanning line GLA and the second scanning line GWG1 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. Furthermore, 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.

[0058] One end of the semiconductor layer 61 is connected to the source electrode 62 via a contact hole H1. The other end of the semiconductor layer 61 is connected to the drain electrode 63 via a contact hole H2. The portion of the output signal line SLS that overlaps with the semiconductor layer 61 serves as the source electrode 62. The 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 connection and disconnection between the photodiode 30 and the output signal line SLS.

[0059] 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, and 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.

[0060] Next, the layer structure of the optical sensor 5 will be described. Fig. 9 is a cross-sectional view taken along line IX-IX' in Fig. 8. In Fig. 9, in order to show the relationship between the layer structure of the detection area AA (see Fig. 5) and the layer structure of the peripheral area GA (see Fig. 5), a cross-section along line IX-IX' and a cross-section of a portion of the peripheral area GA including the second transistor TrG are shown connected in a schematic manner. Furthermore, Fig. 7 shows a cross-section of a portion of the peripheral area GA including the terminal portion 72 connected in a schematic manner.

[0061] 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) is referred to as the "upper side" or "top." The direction from the photodiode 30 toward the substrate 21 is 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.

[0062] 9, the substrate 21 is an insulating substrate, and may be, for example, a glass substrate such as quartz or alkali-free glass. The first transistor Tr, various wirings (scanning lines GLS and output signal lines SLS), and an insulating layer are provided on one surface of the substrate 21 to form the 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.

[0063] 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, and are made of, for example, silicon oxide (SiO ２ ), silicon nitride (SiN), etc. Furthermore, each inorganic insulating layer is not limited to a single layer, and may be a laminated film.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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. 7 .

[0069] 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.

[0070] 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 array substrate 2. The array substrate 2 is a drive circuit board that drives the sensor for each predetermined detection area. The array substrate 2 has a substrate 21, and a first transistor Tr, a second transistor TrG, various wirings, etc., provided on the substrate 21.

[0071] 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 stacked. 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).

[0072] 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.

[0073] 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.

[0074] 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.

[0075] Insulating layers 22f and 22g are provided on the first organic insulating layer 23a. The insulating layer 22f covers the periphery of the upper electrode 34 and has an opening at a position overlapping the upper electrode 34. The connection wiring 36 is connected to the upper electrode 34 at a portion of the upper electrode 34 where the insulating layer 22f is not provided. The insulating layer 22g is provided on the 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 the insulating layer 22g. In the case of an organic semiconductor photodiode, an insulating layer 22h may be further provided thereon.

[0076] 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.

[0077] The semiconductor layer 81 is polysilicon. More preferably, the semiconductor layer 81 is 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.

[0078] The gate electrode 84 is provided above the semiconductor layer 81 via the insulating layer 22b. 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.

[0079] 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.

[0080] 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 so as to communicate with the insulating layers 22c, 22d, and 22e and the first organic insulating layer 23a.

[0081] 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. 8).

[0082] 9 shows one terminal portion 72, a plurality of terminal portions 72 are arranged at intervals. The plurality of terminal portions 72 are electrically connected to the wiring substrate 510 (see FIG. 5) by, for example, an anisotropic conductive film (ACF) or the like.

[0083] FIG. 10 is a diagram illustrating the relationship between the incidence dependency of the transmittance of the light guiding film and the incidence dependency of the reflectance of the wire grid polarizer in the first embodiment.

[0084] 2 and 10 , when the incident angle θ of light L incident on the light guiding film LG is 0°<θ<43°, the light L is irradiated onto the surface skin interface of the object FG via the interface between the light guiding film LG and the air or directly. In this case, the first polarized light L1 transmits through the light guiding film LG with a transmittance Ts1 of 80% or more, and the second polarized light L2 transmits through the light guiding film LG with a transmittance Tp1 of approximately 100%. Here, the transmittance Ts1 is the rate at which the first polarized light L1 transmits through the light guiding film LG. The transmittance Tp1 is the rate at which the second polarized light L2 transmits through the light guiding film LG.

[0085] At this time, the wire grid polarizer WG1 reflects the first polarized light L1 with a reflectance Rs of 80% or more and does not reflect the second polarized light L2. The first polarized light L1 is irradiated onto the epidermal surface of the object FG and is transmitted through or reflected from the epidermal surface. The first polarized light L1 reflected from the epidermal surface of the object FG does not pass through the wire grid polarizer WG1 and is therefore not detected by the optical sensor 5.

[0086] 2 and 10 , when the incident angle θ is 43°<θ<75°, light L is totally reflected between the light guiding film LG and the air interface. However, when the light guiding film LG and the object to be detected FG are in contact with each other, the light L is irradiated onto the epidermal surface when the incident angle θ is within the range of 0°≦θ<75°, and the first polarized light L1 and the second polarized light L2 are transmitted from the light guiding film LG to the object to be detected FG with transmittances Tp2 and Ts2 of approximately 100%, respectively. Here, transmittance Ts2 is the rate at which the first polarized light L1 is transmitted from the light guiding film LG to the object to be detected FG. Transmittance Tp2 is the rate at which the second polarized light L2 is transmitted from the light guiding film LG to the object to be detected FG.

[0087] In this case, when the incident angle θ is 43°<θ<75°, the wire grid polarizer WG1 reflects the first polarized light L1 with a reflectance Rs of 90% or more. As the incident angle θ increases, the reflectance Rp of the second polarized light L2 also increases, and the second polarized light L2 is reflected with a reflectance Rp of 3% to 40%. The second polarized light L2 is contained in a portion of the light reflected by the wire grid polarizer WG1, and is also contained in a portion of the light reflected from the surface skin interface of the detected object FG. The second polarized light L2 reflected from the surface skin interface of the detected object FG is transmitted through the wire grid polarizer WG1, but cannot be detected by the light receiving element 3 because the acceptance angle of the optical filter layer 50 is greater than approximately 20°.

[0088] Therefore, the first polarized light L1 from the surface of the object FG, which is a source of noise, can be significantly reduced, and the optical signal detected by the light receiving element 3 is mainly the second polarized light L2 of the backscattered light from the dermis region, making it possible to image subcutaneous blood vessels, etc. with a high SNR.

[0089] (Embodiment 2) Fig. 11 is a cross-sectional view schematically showing a cross section of a detection device according to embodiment 2. Fig. 12 is an explanatory diagram showing the relationship between the incidence dependency of the transmittance of a light guiding film and the incidence dependency of the reflectance of a wire grid polarizer in embodiment 2. In the following description, the same components as those described in the above embodiments are designated by the same reference numerals, and redundant description will be omitted.

[0090] As shown in FIG. 11, in a detection device 1A according to the second embodiment, a light-transmitting protection film 80 is disposed on a detection surface SF of a light guide film LG on the side of a detection target FG.

[0091] The protective film 80 is a light-transmitting film that is excellent in heat resistance and durability. The protective film 80 is made of, for example, silicone rubber, polyurethane, or PET (Poly Ethylene Terephthalate). This can reduce the skin irritation of the detection object FG.

[0092] The refractive index of the protective film 80 is greater than the refractive index (1.487) of the light guide film LG. The refractive index of the protective film 80 is also greater than the refractive index (1.43) of the epidermis of the detection object FG. The refractive index of the protective film 80 is, for example, 1.63.

[0093] 12, the incident angle θ of the light incident on the epidermis surface of the subject FG is reduced from 75° to 62°. At this time, when light L travels from the light guide film LG to the protective film 80, it travels from a medium with a small refractive index to a medium with a large refractive index, and therefore the incident angle θ becomes smaller, making it easier for the light L to enter the skin. This makes it possible to reduce the surface reflection component (first polarized light L1) from the skin surface, which is a source of noise.

[0094] Furthermore, when light L travels from the protective film 80 toward the surface of the object to be detected FG, it travels from a medium with a high refractive index to a medium with a low refractive index, and therefore, if the incident angle θ is greater than the critical angle, the light L is totally reflected on the surface of the protective film 80, and the proportion of light guided to the entire surface of the optical sensor 5 increases.

[0095] When the light-guiding film LG is wrapped around the wrist or the like and curvature occurs, the incident angle θ on the inner diameter side of the light-guiding film LG effectively increases, making total reflection at the air interface more likely, further narrowing the range of light irradiation angles onto the epidermis, and reducing the surface reflection component from the skin surface, which is a source of noise.

[0096] (Embodiment 3) Fig. 13 is a perspective view schematically showing an example of a detection device according to embodiment 3. Fig. 14 is a perspective view schematically showing an example different from the detection device of Fig. 13. Fig. 15 is a perspective view schematically showing an example different from the detection device of Fig. 13. In the following description, the same components as those described in the above-mentioned embodiments are assigned the same reference numerals, and duplicate description will be omitted.

[0097] The light sources LS1, LS2, and LS3 are arranged on two orthogonal sides or two or three opposing sides of the light guiding film LG. Specifically, as shown in Fig. 13 , in the detection device 1B according to the third embodiment, the light sources LS1 are provided on a first side surface of the light guiding film LG, and the light sources LS2 are provided on a second side surface of the light guiding film LG that is orthogonal to the first side surface and does not have a wiring substrate 510.

[0098] The polarized light components that are reflected or transmitted depend on the wire direction of the wire grid polarizer WG1, regardless of the incident direction of the light L. The first polarized light L1, which vibrates parallel to the wire direction of the wire grid polarizer WG1, is reflected by the wire grid polarizer WG1, while the second polarized light L2, which vibrates orthogonal to the wire direction of the wire grid polarizer WG1, is transmitted through the wire grid polarizer WG1. As shown in Figure 4A, when the light incident from the multiple light sources LS1 is orthogonal to the wire grid polarizer WG1 (orthogonal to the second direction Dy), the first polarized light L1, which vibrates parallel to the wire direction, is reflected by the wire grid polarizer WG1, and the second polarized light L2, which vibrates orthogonal to the wire direction, is transmitted through the wire grid polarizer WG1. 4B , when the light incident from the light sources LS2 arranged at a position perpendicular to the light sources LS1 is parallel to the wire grid polarizer WG1 (i.e., parallel to the second direction Dy), the first polarized light L1 vibrating parallel to the wire direction is reflected by the wire grid polarizer WG1, and the second polarized light L2 vibrating perpendicular to the wire direction is transmitted through the wire grid polarizer WG1. Therefore, the polarized light components reflected by or transmitted through the wire grid WG1 of the light sources LS1 and LS2, which are arranged orthogonal to each other but have different incident directions, exhibit the same polarization direction.

[0099] 14 , in the detection device 1C, the plurality of light sources LS1 are provided on a first side surface of the light guiding film LG, and the plurality of light sources LS3 are provided on a third side surface opposite the first side surface of the light guiding film LG. As with the light incident from the plurality of light sources LS1, the first polarized light L1 of the light incident from the plurality of light sources LS3 is reflected by the wire grid polarizer WG1, and the second polarized light L2 is transmitted through the wire grid polarizer WG1.

[0100] 15 , in the detection device 1D, the plurality of light sources LS1 are provided on a first side surface of the light guiding film LG, and the plurality of light sources LS2 are provided on a second side surface of the light guiding film LG that is perpendicular to the first side surface and does not have a wiring substrate 510. The plurality of light sources LS3 are provided on a third side surface of the light guiding film LG that is opposite the first side surface. The plurality of light sources LS2 are not provided on the side surface on which the wiring substrate 510 is provided.

[0101] This increases the amount of light propagating within the light guide film LG, increasing the amount of light reflected from the measurement target portion of the detection object FG, and improving the efficiency of light guide incident on the optical sensor 5 side.

[0102] 16 is a plan view schematically showing a detection device according to embodiment 4. In the following description, the same components as those described in the above-mentioned embodiments are denoted by the same reference numerals, and redundant description will be omitted.

[0103] 16, in the detection device 1E, the light sources LS1, LS2, and LS3 each have a first light source LS11 and a second light source LS12. The first light source LS11 and the second light source LS12 are arranged alternately. The first light source LS11 and the second light source LS12 emit at least one of red light, green light, infrared light, near-infrared light, and visible light. The wavelength of the light from the first light source L11 is different from the wavelength of the light from the second light source L12.

[0104] For example, the first light source LS11 emits near-infrared light or infrared light. The second light source LS12 emits green light or red light. The green light has a wavelength of, for example, 490 nm or more and 550 nm or less. The red light has a wavelength of, for example, 640 nm or more and 770 nm or less. The infrared light has a wavelength of, for example, approximately 2500 nm or more and approximately 25 μm or less. The near-infrared light has a wavelength of, for example, approximately 770 nm or more and approximately 2500 nm or less. In this embodiment, light sources of two different wavelengths are arranged, but three or more different light sources may be arranged alternately.

[0105] This allows the two different wavelengths to be incident on the optical sensor 5 more uniformly, improving the light guide efficiency.

[0106] 17 is a perspective view schematically showing a detection device according to embodiment 5. In the following description, the same components as those described in the above embodiments are denoted by the same reference numerals, and redundant description will be omitted.

[0107] As shown in Figure 17, in the detection device 1F of embodiment 5, the shape of the light entrance portion LG1 provided on the side of the light guide film LG where light L is incident is trapezoidal in cross-sectional view in a plane (Dx-Dz plane) perpendicular to the second direction Dy.

[0108] The light entrance portion LG1 has two parallel sides. The shorter of the two sides faces the light guide film LG. The longer of the two sides faces the light source LS. Therefore, the thickness of the side of the light entrance portion LG1 facing the light source LS is greater than the thickness of the light guide film LG.

[0109] This allows light to be reliably emitted from the light source LS into the light guide film LG, thereby reducing the amount of light leakage.

[0110] (Embodiment 6) Fig. 18 is a cross-sectional view that schematically shows a cross section of a detection device according to embodiment 6. Fig. 19 is a perspective view that schematically shows a detection device according to embodiment 6. In the following description, the same components as those described in the above embodiments are denoted by the same reference numerals, and redundant description will be omitted.

[0111] As shown in Figure 18, in the detection device 1G of embodiment 6, the side of the light-guiding film LG is inclined with respect to the normal direction of the detection surface SF on the side of the light-guiding film LG facing the object to be detected FG, and the light source LS faces the side of the light-guiding film LG facing the object to be detected FG.

[0112] This reduces the loss of light incident from the light source LS and improves the light guide efficiency to the light guide film LG. In addition, the light irradiation intensity of the light source LS increases, and power consumption can be reduced.

[0113] 19 , in the detection device 1G according to the sixth embodiment, the light guiding film LG is curved. The array substrate 2 (substrate 21) is made of resin and is a flexible substrate having flexibility. The flexible array substrate 2 (substrate 21) is curved along the curvature of the light guiding film LG.

[0114] (Seventh embodiment) Fig. 20 is a cross-sectional view schematically showing a cross section of a detection device according to a seventh embodiment. Fig. 21 is a plan view schematically showing a detection device according to the seventh embodiment. Fig. 22 is an explanatory diagram showing the transmittance of a high refractive index waveguide layer versus the angle of incidence in the seventh embodiment. In the following description, the same components as those described in the above-mentioned embodiments are assigned the same reference numerals, and redundant description will be omitted.

[0115] 20 , in a detecting device 1H according to the seventh embodiment, a detection surface SF of a light guiding film LG on the side of a detection target FG is provided with a protective film 80 and a high-refractive index waveguide layer 90. The high-refractive index waveguide layer 90 is disposed between the protective film 80 and the light guiding film LG.

[0116] The protective film 80 is made of, for example, polydimethylsiloxane (PDMS) or the like, which has a low refractive index.

[0117] A film with a high refractive index is used for the high-refractive-index waveguide layer 90. The high-refractive-index waveguide layer 90 is, for example, polyacrylate with dispersed zirconia nanoparticles or titanium oxide nanoparticles. The refractive index of the high-refractive-index waveguide layer 90 is 1.65 to 1.71, which is greater than the refractive index of the light guide film LG (1.487) and the refractive index of the protective film 80 (1.41).

[0118] As shown in Figure 21, the high-refractive-index waveguide layer 90 has a triangular shape in a plan view. This changes the angle of incidence of light L guided from the light-guiding film LG, which has a different refractive index, to the high-refractive-index waveguide layer 90, and the light L gradually leaks from two sides of the triangle, allowing the light to be guided uniformly within the plane. Note that the number of light sources and the number of high-refractive-index light-guiding layers do not need to match. Furthermore, the two sides of the triangle of the high-refractive-index waveguide layer 90 may be curved rather than straight.

[0119] FIG. 22 is an explanatory diagram showing the transmittance of the high refractive index waveguide layer versus the incident angle in the seventh embodiment.

[0120] 20 and 22 , when the incident angle θ of light L incident on the light guide film LG is 0°<θ<60°, the light L incident on the high-refractive-index waveguide layer 90 is refracted by the protective film 80 and is irradiated onto the epidermis. In this case, the first polarized light L1 and the second polarized light L2 are transmitted from the high-refractive-index waveguide layer 90 to the detection object FG with transmittances Tp3 and Ts3 of approximately 100%, respectively. Here, the transmittance Ts3 is the rate at which the first polarized light L1 is transmitted from the high-refractive-index waveguide layer 90 to the protective film 80. The transmittance Tp3 is the rate at which the second polarized light L2 is transmitted from the high-refractive-index waveguide layer 90 to the protective film 80.

[0121] 20 and 22 , when the incident angle θ is in the range of 60°<θ<65°, light L incident on the high-refractive-index waveguide layer 90 is refracted by the light-guiding film LG and is irradiated onto the wire-grid polarizer WG1. In this case, the first polarized light L1 and the second polarized light L2 are incident from the high-refractive-index waveguide layer 90 to the light-guiding film LG with transmittances Tp4 and Ts4 of approximately 100%, respectively. Here, the transmittance Ts4 is the proportion of the first polarized light L1 that is transmitted through the high-refractive-index waveguide layer 90. The transmittance Tp4 is the proportion of the second polarized light L2 that is transmitted through the high-refractive-index waveguide layer 90.

[0122] 20 and 22 , when the incident angle θ is 65°<θ<90°, the light L incident on the high-refractive-index waveguide layer 90 propagates through the high-refractive-index waveguide layer 90 and is guided toward the reflector FL1. In this case, the first polarized light L1 and the second polarized light L2 are transmitted from the light-guiding film LG to the high-refractive-index waveguide layer 90 with transmittances Tp5 and Ts5, respectively. Here, the transmittance Ts5 is the rate at which the first polarized light L1 is transmitted from the light-guiding film LG to the high-refractive-index waveguide layer 90 and penetrates therein. The transmittance Tp5 is the rate at which the second polarized light L2 is transmitted from the light-guiding film LG to the high-refractive-index waveguide layer 90 and penetrates therein.

[0123] This allows the light to be uniformly irradiated onto the entire surfaces of the plurality of optical sensors 5, thereby improving detection accuracy.

[0124] The front light FL has a reflector FL1 on the side of the light guide film LG opposite to the side facing the light source LS. The side of the reflector FL1 is inclined at an angle equal to or greater than the acceptance angle, which is the maximum angle at which light L enters the optical filter layer 50.

[0125] This allows light incident on the reflector FL1 to be reflected toward the epidermis via the high-refractive-index waveguide layer 90 or the protective film 80, making it possible to effectively utilize the light guided within the high-refractive-index waveguide layer 90 and the light-guiding film LG, and also improving the power efficiency of the detection device.

[0126] Eighth Embodiment Fig. 23 is a cross-sectional view schematically showing a cross section of a detection device according to embodiment 8. Fig. 24 is an explanatory diagram showing the transmittance of a light guiding film versus the angle of incidence in embodiment 8. In the following description, the same components as those described in the above embodiments are denoted by the same reference numerals, and redundant description will be omitted.

[0127] 23, the detection device 1I according to the eighth embodiment includes an optical sensor 5, a front light FL, and an optical filter layer 50. The optical sensor 5, the optical filter layer 50, and the front light FL are stacked in this order on a substrate 21.

[0128] 23 and 24 , when the incident angle θ of light L incident on the light guide film LG is 0°<θ<43°, the first polarized light L1 passes through the optical filter layer 50 with a transmittance Ts1 of 80% or more, and the second polarized light L2 passes through the optical filter layer 50 with a transmittance Tp1 of almost 100%. Here, the transmittance Ts6 is the rate at which the first polarized light L1 passes through the optical filter layer 50. The transmittance Tp6 is the rate at which the second polarized light L2 passes through the optical filter layer 50.

[0129] At this time, light is irradiated onto the epidermis either through the air interface or directly, and if the acceptance angle of the optical filter layer 50 is within approximately 20°, the surface reflection of the epidermis or the backscattered light from the measurement target area (e.g., blood vessels inside the skin) is detected by the light receiving element 3.

[0130] 23 and 24 , when the incident angle θ is 43°<θ<75°, the light L is totally reflected between the light guiding film LG and the air interface and is directly irradiated onto the epidermis at the contact interface between the light guiding film LG and the object to be detected FG. In this case, when the incident angle θ is in the range of 0°<θ<75°, the first polarized light L1 and the second polarized light L2 are transmitted through the optical filter layer 50 and penetrate into the object to be detected FG with transmittances Tp7 and Ts2 of approximately 100%, respectively. Here, the transmittance Ts7 is the rate at which the first polarized light L1 is transmitted through the optical filter layer 50 and penetrates into the object to be detected FG. The transmittance Tp7 is the rate at which the second polarized light L2 is transmitted through the optical filter layer 50 and penetrates into the object to be detected FG.

[0131] At this time, if the light reflected from the surface of the epidermis or backscattered light from the measurement target area (for example, blood vessels inside the skin) has an acceptance angle of the optical filter layer 50 within approximately 20°, it is detected by the light receiving element 3.

[0132] 23 , the front light FL has a plurality of light sources LS that irradiate a first side surface of the light guiding film LG with light L, and has a reflector FL1 on a second side surface of the light guiding film LG opposite the light sources LS and on a third side surface perpendicular to the first side surface of the light sources LS. The side surface of the reflector FL1 is inclined at an angle equal to or greater than the acceptance angle, which is the maximum angle at which light L enters the optical filter layer 50.

[0133] This allows the light incident on the reflector FL1 to be reflected toward the side facing the light source LS, making it possible to effectively utilize the light guided through the light-guiding film LG and also improving the power efficiency of the detection device.

[0134] Fig. 25 is a cross-sectional view schematically showing an example of a light-receiving element according to embodiment 8. Fig. 26 is a cross-sectional view schematically showing an example different from the light-receiving element of Fig. 25. Fig. 27 is a cross-sectional view schematically showing an example different from the light-receiving element of Fig. 26.

[0135] The photodiode 30 is any one of an organic photodiode (OPD), a quantum dot, and a perovskite.

[0136] 25 , the photodiode 30 includes a lower electrode 35, a lower buffer layer 350, a semiconductor layer 31, an upper buffer layer 340, and an upper electrode 34. In the photodiode 30, the lower electrode 35, the lower buffer layer 350 (hole transport layer), the semiconductor layer 31, the upper buffer layer 340 (electron transport layer), and the upper electrode 34 are stacked in this order in a direction perpendicular to the third direction Dz.

[0137] The lower electrode 35 may be the anode electrode of the photodiode 30, and the upper electrode 34 may be the cathode electrode of the photodiode 30. In this case, the lower buffer layer 350 may be a hole transport layer, and the upper buffer layer 340 may be an electron transport layer.

[0138] The semiconductor layer 31 has acceptor molecules 311 and donor molecules 312. The semiconductor layer 31 has a bulk heterostructure in which the acceptor molecules 311 and the donor molecules 312 are mixed together.

[0139] The photodiode 30 is, for example, a quantum dot. As shown in Fig. 26, the semiconductor layer 31 has quantum dots 313. The quantum dots 313 are nano-sized semiconductor particles, and for example, the main component of the core of the quantum dot is PbS, and the core is covered with a ligand (covering layer) such as oleic acid or a polymer. The quantum dots 313 are arranged to form a quantum well structure.

[0140] The photodiode 30 is made of, for example, perovskite. As shown in FIG. 27, the semiconductor layer 31 is made of, for example, barium titanate (BaTiO ３ The semiconductor layer 31 includes a ternary transition metal oxide such as lead halide (CH3NH3PbI3) and forms a perovskite structure. The semiconductor layer 31 is, for example, a lead halide semiconductor (CH3NH3PbI3), which is also a solar cell material.

[0141] Ninth Embodiment Fig. 28 is a cross-sectional view schematically showing a cross section of a detection device according to embodiment 9. Fig. 29 is an explanatory diagram showing the relationship between the transmittance of a light guiding film and the transmittance of a protective film with respect to the incident angle in embodiment 9. Fig. 30 is an explanatory diagram explaining the transmittance of a light guiding film with respect to the incident angle, which is different from the detection device in Fig. 29. In the following explanation, the same components as those explained in the above-mentioned embodiments are assigned the same reference numerals, and redundant explanations will be omitted.

[0142] 28 , a detection device 1J according to the ninth embodiment includes an optical sensor 5, a front light FL, and an optical filter layer 50. The optical sensor 5, the optical filter layer 50, and the front light FL are stacked in this order on a substrate 21.

[0143] The front light FL has a plurality of light sources LS that emit light onto the first side surface of the light guide film LG, and has a light-transmitting protective film 80 on the detection surface SF side of the light guide film LG.

[0144] A case will be described in which the material of the light guiding film LG is, for example, TAC (Triacetylcellulose) and the material of the protective film 80 is, for example, polydimethylsiloxane (PDMS). In this case, the refractive index of the protective film 80 is, for example, 1.141, which is smaller than the refractive index (1.487) of the light guiding film LG. The refractive index of the protective film 80 is also smaller than the refractive index (1.43) of the epidermis of the detection object FG.

[0145] 29 , when the protective film 80 is not provided, the first polarized light L1 transmits through the light guiding film LG with a transmittance Ts6 of 80% or more within the incident angle θ range of 0°<θ<43°, and the second polarized light L2 transmits through the light guiding film LG with a transmittance Tp6 of approximately 100%, resulting in the light being irradiated directly or via the air interface onto the surface of the object FG. On the other hand, when the incident angle θ is 43°≦θ≦75°, the light L is totally reflected between the light guiding film LG and the air interface and is not irradiated onto the surface of the object FG. When the light guiding film LG and the surface of the object FG are in contact with each other, the first polarized light L1 and the second polarized light L2 transmit through the light guiding film LG with transmittances Tp7 and Ts7 of approximately 100% within the incident angle θ range of 0°<θ<75°, resulting in the light being irradiated onto the surface of the object FG.

[0146] 28 and 30 , when a protective film 80 is provided on the detection surface SF side of the light guiding film LG, if the incident angle θ at which light L enters the protective film 80 is 0°<θ<43°, the light L is irradiated to the surface skin interface of the detection object FG via the air interface or directly. In this case, the first polarized light L1 transmits through the protective film 80 with a transmittance Ts8 of 80% or more, and the second polarized light L2 transmits through the protective film 80 with a transmittance Tp8 of approximately 100%. Here, the transmittance Ts8 is the rate at which the first polarized light L1 transmits through the protective film 80. The transmittance Tp8 is the rate at which the second polarized light L2 transmits through the protective film 80.

[0147] 28 and 30 , when the incident angle θ is in the range of 0°<θ<75°, light L is incident from the light guiding film LG to the protective film 80. In this case, when the incident angle θ is in the range of 0°<θ<75°, the first polarized light L1 and the second polarized light L2 are transmitted from the light guiding film LG to the protective film 80 with transmittances Tp9 and Ts9 of approximately 100%, respectively. Here, the transmittance Ts9 is the rate at which the first polarized light L1 is transmitted from the light guiding film LG to the protective film 80. The transmittance Tp9 is the rate at which the second polarized light L2 is transmitted from the light guiding film LG to the protective film 80.

[0148] 28 and 30 , when a protective film 80 having a lower refractive index than the light guiding film LG is provided, light L is irradiated onto the surface skin interface of the detection target FG, which is in direct contact with the protective film 80, when the incident angle θ is in the range of 0°<θ<90°. In this case, when the incident angle θ is in the range of 75°<θ<80°, the first polarized light L1 and the second polarized light L2 are transmitted through the protective film 80 and enter the detection target FG with transmittances Tp10 and Ts10 of approximately 100%, respectively. Here, the transmittances Ts10 and Tp10 are the proportions of the first polarized light L1 and the second polarized light L2 that are transmitted through the protective film 80 and enter the detection target FG, respectively.

[0149] 29 and 30 , the incident angle θ of light incident from the protective film 80 onto the skin surface of the contacting detection object FG is increased from 75° to 90°, thereby improving the efficiency of guiding light to the optical sensor 5. Furthermore, if a curvature occurs when the light is wrapped around the wrist or the like, the incident angle θ on the inner diameter side of the light guiding film effectively becomes larger, and therefore, if there is a protective film 80 with a low refractive index, this is effective in maintaining the amount of light incident on the detection object FG.

[0150] Tenth Embodiment Fig. 31 is a plan view schematically showing a detection device according to embodiment 10. Fig. 32 is an explanatory diagram showing the relationship between the transmittance of a light guiding film and the transmittance of a protective film with respect to the angle of incidence in embodiment 10. In the following description, the same components as those described in the above embodiments are denoted by the same reference numerals, and redundant description will be omitted.

[0151] In the detection device 1K according to the tenth embodiment, the light guiding film LG is made of, for example, triacetylcellulose (TAC), and the protective film 80 is made of, for example, polyethylene terephthalate (PET). In this case, the refractive index of the protective film 80 is, for example, 1.63, which is greater than the refractive index (1.487) of the light guiding film LG. The refractive index of the protective film 80 is also greater than the refractive index (1.43) of the epidermis of the detection object FG.

[0152] 31 and 32 , when the incident angle θ at which light L enters the protective film 80 is 0°<θ<38°, the light L is irradiated to the surface skin interface of the detection object FG via the air interface or directly. When the incident angle θ is 38°<θ<62°, the light L is totally reflected between the protective film 80 and the air interface and is not irradiated to the surface skin interface of the detection object FG. When the incident angle θ is 62°<θ<90°, the light L is incident from the light guiding film LG to the protective film 80.

[0153] 31 and 32 , the incident angle θ at which light L is incident on the epidermis surface of the detection subject FG is reduced from 75° to 62°. At this time, when light L travels from the light guiding film LG to the protective film 80, it travels from a medium with a small refractive index to a medium with a large refractive index, and therefore the incident angle θ becomes smaller, making it easier for the light L to enter the skin. This makes it possible to reduce the surface reflection component from the skin surface, which is a source of noise.

[0154] Furthermore, when light L travels from the protective film 80 toward the surface of the object to be detected FG, it travels from a medium with a high refractive index to a medium with a low refractive index, and therefore, if the incident angle θ is greater than the critical angle, the light L is totally reflected on the surface of the protective film 80, and the proportion of light guided to the entire surface of the optical sensor 5 increases.

[0155] When the light-guiding film LG is wrapped around the wrist or the like and curvature occurs, the incident angle θ on the inner diameter side of the light-guiding film LG increases, but the incident angle θ incident on the epidermis surface via the air interface decreases, thereby narrowing the range of light irradiation angles on the epidermis and reducing the surface reflection components from the skin surface that cause noise.

[0156] 33 is a plan view schematically showing a detection device according to embodiment 11. In the following description, the same components as those described in the above-mentioned embodiments are denoted by the same reference numerals, and redundant description will be omitted.

[0157] 33 , in a detection device 1L according to the ninth embodiment, the SF side of the light guiding film LG is provided with a high-refractive-index waveguide layer 90. The high-refractive-index waveguide layer 90 is disposed between the protection film 80 and the light guiding film LG.

[0158] This allows the light to be uniformly irradiated onto the entire surfaces of the plurality of optical sensors 5, thereby improving detection accuracy.

[0159] 33 , the inclination angle of the side surface of the light guiding film LG onto which light L is incident forms an angle other than 90° with respect to the detection surface SF side of the light guiding film LG. In this case, the side surface of the light guiding film LG is inclined with respect to the detection surface SF on the side of the light guiding film LG facing the object to be detected FG, and the light source LS faces the side surface of the light guiding film LG facing the object to be detected FG.

[0160] This reduces the loss of light incident from the light source LS and improves the light guide efficiency to the light guide film LG. In addition, the light irradiation intensity of the light source LS increases, and power consumption can be reduced.

[0161] 34 is a perspective view schematically showing a detection device according to embodiment 12. In the following description, the same components as those described in the above-mentioned embodiments are denoted by the same reference numerals, and redundant description will be omitted.

[0162] 34, a detection device 1M according to the twelfth embodiment includes an optical sensor 5, a front light FL, and an optical filter layer 50. The optical sensor 5, the optical filter layer 50, and the front light FL are stacked in this order on a substrate 21.

[0163] A gap GP is provided between the light guide film LG and the optical filter layer 50. The gap GP is bonded with, for example, an optical resin (not shown). The gap GP may be, for example, an air layer.

[0164] As shown in Figure 34, the shape of the light entrance portion LG1 provided on the side of the light guide film LG where light L is incident is trapezoidal in cross section in a plane (Dx-Dz plane) perpendicular to the second direction Dy.

[0165] The operation and effects of the detection device 1M according to the twelfth embodiment are similar to those of the detection device 1F according to the fifth embodiment, and therefore detailed description thereof will be omitted.

[0166] 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.

[0167] For example, combinations of the aspects of the first to twelfth embodiments naturally fall within the technical scope of the present disclosure.

[0168] 1A, 1B, 1C, 1D, 1E, 1F, 1G, 1H, 1I, 1J, 1K, 1L, 1M Detecting device 2 Array substrate 3 Light receiving element 5 Optical sensor 10 Sensor section 21 Substrate 30 Photodiode 313 Quantum dot 50 Optical filter layer 51 Light guide path 55 Light blocking section 80 Protective film 90 High refractive index waveguide layer Dx First direction Dy Second direction Dz Third direction FL Front light FL1 Reflector FG Object to be detected LG Light guide film LG1 Light entrance section LS, LS1, LS2, LS3 Light source LS11 First light source LS12 Second light source SF Detection surface WG Wire grid polarizer WG1 Wire grid polarizer

Claims

1. A detection device comprising: an optical sensor having a plurality of light receiving elements that receive light; and a frontlight arranged on the object to be detected side of the optical sensor and comprising a light guiding film and a plurality of light sources that irradiate a first side of the light guiding film, wherein a wire grid polarizer is arranged between the optical sensor and the frontlight for separating the light incident from the light sources into first and second polarized light.

2. The detection device according to claim 1, wherein the light guiding film propagates either the first polarized light or the second polarized light, and the light guiding film transmits the other of the first polarized light or the second polarized light and outputs it to the optical sensor side.

3. The detection device according to claim 1 or 2, wherein an optical filter layer is disposed between the light receiving element and the wire grid polarizer.

4. The detection device according to claim 3, wherein a light-transmitting protective film is disposed on the detection surface of the light-guiding film facing the object to be detected.

5. The detection device according to claim 4, wherein the refractive index of the protective film is greater than the refractive index of the light-guiding film.

6. The detection device according to claim 5, wherein each of the plurality of light receiving elements is an organic photodiode.

7. The detection device according to claim 6, wherein the light source has a first light source and a second light source, the first light source and the second light source are arranged alternately, the first light source and the second light source emit at least one of infrared light, near-infrared light, red light and green light, and the wavelength of the light of the first light source is different from the wavelength of the light of the second light source.

8. The detection device according to claim 7, wherein the plurality of light sources are arranged on two perpendicular sides, or two or three opposing sides, of the light-guiding film.

9. The detection device according to claim 7, further comprising a light entrance section on a side of the light-guiding film where light is incident, the light entrance section having a trapezoidal shape in cross section.

10. The detection device according to claim 7, wherein a side surface of the light-guiding film is inclined with respect to a normal direction of a detection surface of the light-guiding film facing the object to be detected, and the light source faces the side surface.

11. The detection device according to claim 7, further comprising a high refractive index waveguide layer on the detection surface side of the light guiding film, the high refractive index waveguide layer having a refractive index higher than the refractive indexes of the light guiding film and the protective film, the high refractive index waveguide layer being disposed between the protective film and the light guiding film.

12. The detection device described in claim 7, wherein the front light has a reflector on a side of the light-guiding film opposite to the side facing the light source, and the side of the reflector is inclined at an angle equal to or greater than the acceptance angle, which is the maximum angle at which light enters the optical filter layer.

13. A detection device comprising: an optical sensor having a plurality of light receiving elements that receive light; a frontlight arranged on the object to be detected side of the optical sensor and having a light guiding film; and an optical filter layer arranged between the optical sensor and the frontlight, wherein the optical sensor, the optical filter layer, and the frontlight are stacked in this order, and the frontlight has a plurality of light sources that irradiate light onto a first side of the light guiding film, and has a reflector on a second side of the light guiding film opposite the light sources.

14. The detection device according to claim 13, wherein the second side surface is inclined at an angle equal to or greater than an acceptance angle that is the maximum angle at which light enters the optical filter layer.

15. The detection device according to claim 13, wherein each of the plurality of light receiving elements is at least one of an organic photodiode, a quantum dot, and a perovskite.

16. A detection device comprising: an optical sensor having a plurality of light receiving elements that receive light; a frontlight arranged on the object to be detected side of the optical sensor and having a light guiding film; and an optical filter layer arranged between the optical sensor and the frontlight, the optical sensor, the optical filter layer, and the frontlight being stacked in this order, the frontlight having a plurality of light sources that irradiate light onto a first side of the light guiding film, and a light-transmitting protective film on the detection surface side of the light guiding film.

17. The detection device according to claim 16, wherein the refractive index of the protective film is greater than the refractive index of the light-guiding film.

18. The detection device according to claim 16, further comprising a high refractive index waveguide layer on the detection surface side of the light guiding film, the high refractive index waveguide layer having a refractive index higher than the refractive indexes of the light guiding film and the protective film, the high refractive index waveguide layer being disposed between the protective film and the light guiding film.

19. A detection device comprising: an optical sensor having a plurality of light receiving elements that receive light; a frontlight arranged on the object side of the optical sensor and having a light guiding film; and an optical filter layer arranged between the optical sensor and the frontlight, wherein the optical sensor, the optical filter layer, and the frontlight are stacked in this order, and the inclination angle of the side of the light guiding film onto which light is incident is an angle other than 90° with respect to the detection surface of the light guiding film.

20. A detection device comprising: an optical sensor having a plurality of light receiving elements that receive light; a frontlight arranged on the object to be detected side of the optical sensor and comprising a light guiding film and a plurality of light sources that irradiate light onto a first side of the light guiding film; and an optical filter layer arranged between the optical sensor and the frontlight, wherein the optical sensor, the optical filter layer, and the frontlight are stacked in this order; the device has a light entrance portion on the side of the light guiding film where light is incident, and the shape of the light entrance portion is trapezoidal when viewed in cross section.