Detection device

Abstract

Provided is a detection device that is makes it possible to improve detection accuracy. The detection device comprises a substrate and a plurality of photodiodes in each of which a lower electrode, a lower buffer layer, an active layer, an upper buffer layer, and an upper electrode are laminated in this order on the substrate. The upper electrode covers the lower buffer layer, the active layer, the upper buffer layer, and the lower electrode. A light-shielding layer is provided in a region in which, in a planar view, an end part of the lower buffer layer, an end part of the active layer, an end part of the upper buffer layer, and an end part of the lower electrode overlap. The lower buffer layer, the active layer, the upper buffer layer, and the lower electrode are disposed separately for each of the plurality of photodiodes.

Description

Detection Device

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

[0002] Optical sensors capable of detecting fingerprint patterns and vein patterns are known (see, for example, Patent Document 1). Among such optical sensors, a sensor having a plurality of organic photodiodes (OPDs) using an organic semiconductor material as an active layer is known. The organic semiconductor material is disposed between a lower electrode and an upper electrode, and a signal line is electrically connected to the lower electrode of the photodiode for outputting a detection signal to a detection circuit.

[0003] Japanese Patent Application Laid-Open No. 2009-32005

[0004] There is a demand for improved detection accuracy in optical sensors having such OPDs.

[0005] An object of the present invention is to provide a detection device that can improve detection accuracy.

[0006] A detection device according to one embodiment of the present invention includes a substrate, a plurality of photodiodes stacked on the substrate in the following order: a lower electrode, a lower buffer layer, an active layer, an upper buffer layer, and an upper electrode; the upper electrode covers the lower buffer layer, the active layer, the upper buffer layer, and the lower electrode; and a light-shielding layer provided in an area overlapping, in plan view, an end of the lower buffer layer, an end of the active layer, an end of the upper buffer layer, and an end of the lower electrode, wherein the lower buffer layer, the active layer, the upper buffer layer, and the lower electrode are arranged at a distance for each of the plurality of photodiodes.

[0007] FIG. 1 is a schematic diagram showing an example of the external appearance of a detection device according to the first embodiment, when a finger is placed inside the detection device, as viewed from the side of the housing. FIG. 2 is a schematic cross-sectional view taken along the line II-II' in FIG. 1. FIG. 3 is a development view showing an example of the optical sensors of the detection device shown in FIG. 1. FIG. 4 is a configuration diagram showing an example of the configuration of the first optical sensor and the second optical sensor shown in FIG. 3. FIG. 5 is a schematic cross-sectional view showing an example of the stacked configuration of the optical sensors taken along the line V-V' in FIG. 4. FIG. 6 is a timing waveform diagram showing the optical response characteristics of a detection device according to a comparative example. FIG. 7 is a timing waveform diagram showing the optical response characteristics of a detection device. FIG. 8 is a schematic cross-sectional view showing an example of the stacked configuration of the optical sensors of a detection device according to a first modification of the first embodiment. FIG. 9 is a development view showing an example of the optical sensors of a detection device according to a second modification of the first embodiment. FIG. 10 is a configuration diagram showing an example of the configuration of the first optical sensor and the second optical sensor shown in FIG. 9. FIG. 11 is a plan view schematically showing a detection device according to a second embodiment. FIG. 12 is a block diagram showing an example of the configuration of a detection device according to the second embodiment. FIG. 13 is a circuit diagram showing a detection device according to the second embodiment. FIG. 14 is an enlarged schematic configuration diagram of a sensor unit according to the second embodiment. FIG. 15 is a plan view showing a light-shielding layer according to the second embodiment. FIG. 16 is a cross-sectional view taken along XVI-XVI' in FIG. 15. FIG. 17 is a cross-sectional view taken along XVII-XVII' in FIG. 15. FIG. 18 is a plan view showing a light-shielding layer according to Modification 1 of the second embodiment. FIG. 19 is a plan view showing a light-shielding layer according to Modification 2 of the second embodiment. FIG. 20 is a plan view showing a light-shielding layer according to Modification 3 of the second embodiment. FIG. 21 is a cross-sectional view taken along XXI-XXI' in FIG. 20. FIG. 22 is a cross-sectional view taken along XXII-XXII' in FIG. 20.

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

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

[0010] (First embodiment) Fig. 1 is a schematic diagram showing an example of the appearance of a detection device according to a first embodiment when a finger is placed inside the detection device as viewed from the side of the housing. Fig. 2 is a schematic cross-sectional view taken along the line A-A in Fig. 1. Fig. 3 is a developed view showing an example of the optical sensors of the detection device shown in Fig. 1. Fig. 4 is a configuration diagram showing an example of the configuration of the first optical sensor and the second optical sensor shown in Fig. 3. Fig. 5 is a schematic cross-sectional view showing an example of the stacked configuration of the optical sensors taken along the line B-B in Fig. 4.

[0011] The detection device 1 shown in FIG. 1 is a ring-shaped device that can be attached and detached to the human body, and is worn on a human finger, which is the object to be detected Fg. Examples of fingers that are the object to be detected Fg include the thumb, index finger, middle finger, ring finger, little finger, etc. The human body is the person to be authenticated, whose identity is verified by the detection device 1. The detection device 1 can detect biometric information about a living organism from the finger on which it is worn. The measurement target is a living organism or part of a living organism, and is the measurement target. The detection device 1 is made into a ring or wristband, making it easy for the user to carry. In the following description, it is assumed that the detection device 1 is used as a ring.

[0012] 2, the detection device 1 includes a housing 200, a light source 60, a first optical sensor 10A, and a second optical sensor 10B. The detection device 1 includes a battery (not shown) inside the housing 200 and is operated by power from the battery.

[0013] The housing 200 is formed in a ring shape (annular shape) that can be attached to the detection subject Fg, and is an attachment member that is attached to a living body. In the example shown in FIG. 2 , the housing 200 includes a sealing film 201 and an exterior part 220. The sealing film 201 and the exterior part 220 are integrally formed into a ring shape. The sealing film 201 houses the light source 60, the first optical sensor 10A, the second optical sensor 10B, etc. inside. The sealing film 201 is formed in a ring shape using a housing material such as a transparent synthetic resin or silicone. The exterior part 220 has a surface of the housing 200 that covers the outer peripheral surface 201A of the sealing film 201. The exterior part 220 is formed in a ring shape using a material such as a metal or a non-transparent synthetic resin. The housing 200 houses a flexible printed circuit board 70, on which the light source 60, the first optical sensor 10A, the second optical sensor 10B, etc. are mounted, inside the sealing film 201. The flexible printed circuit board 70 is housed inside the housing 200 by, for example, forming the housing 200 in a ring shape in a mold and filling a filling material around the flexible printed circuit board 70 .

[0014] As shown in FIG. 3 , the detection device 1 shown in FIG. 1 has four optical sensor elements. The flexible printed circuit board 70 is formed in a deformable band shape and is formed into a ring shape by connecting one end 710 and the other end 720. The flexible printed circuit board 70 has a first mounting area 73 and a second mounting area 74. The first mounting area 73 is an area where the light source 60 and the like are mounted. The second mounting area 74 is an area where the control circuit 122, the power supply circuit 123, and the like are mounted. The flexible printed circuit board 70 has a first substrate 21 mounted so as to straddle the vicinity of the light source 60 in the first mounting area 73. In addition, a second substrate 50 is provided on the first substrate 21. The flexible printed circuit board 70 electrically connects the light source 60, the first optical sensor 10A, the second optical sensor 10B, and the like to the control circuit 122.

[0015] In this embodiment, the first optical sensor 10A and the second optical sensor 10B are provided so as to sandwich the light source 60 in the circumferential direction 200C. That is, the detection device 1 is arranged in the circumferential direction 200C with the first optical sensor 10A, the light source 60, and the second optical sensor 10B lined up in this order. By arranging the first optical sensor 10A and the second optical sensor 10B so as to sandwich the light source 60 in the circumferential direction 200C, the first optical sensor 10A and the second optical sensor 10B can detect light emitted by the light source 60 over a wide range of the housing 200.

[0016] The first substrate 21 is an insulating substrate formed in a strip shape using, for example, a film-like synthetic resin such as PET (Poly Ethylene Terephthalate). The first substrate 21 is deformable and has the first optical sensor 10A and the second optical sensor 10B mounted thereon. The first substrate 21 can be bent in the third direction Dz. The first substrate 21 is attached to the flexible printed circuit board 70, thereby positioning the first optical sensor 10A and the second optical sensor 10B on both sides of the light source 60 in the circumferential direction 200C of the housing 200. The first substrate 21 has a first region 21A where the first optical sensor 10A is mounted and a second region 21B where the second optical sensor 10B is mounted. The first substrate 21 is formed as a single substrate having the first region 21A and the second region 21B.

[0017] The second substrate 50 is an insulating substrate similar to the first substrate 21, and is formed in a strip shape from, for example, PET (Poly Ethylene Terephthalate), which is a film-like synthetic resin. The second substrate 50 covers the sealing film 201 and is a deformable substrate. The second substrate 50 can be curved in the third direction Dz.

[0018] 2 , the flexible printed circuit board 70 is housed inside the housing 200 so that the surface on which the first optical sensor 10A, the second optical sensor 10B, and the light source 60 are mounted faces the inner circumferential surface 200B of the housing 200. If the flexible printed circuit board 70 is translucent, the first optical sensor 10A, the second optical sensor 10B, and the light source 60 may be mounted on the back surface opposite to the front surface. In this case, the light source 60 may be disposed so that it emits light toward the flexible printed circuit board 70 and the light that has passed through the flexible printed circuit board 70 is emitted toward the outside of the housing 200.

[0019] As shown in Fig. 2, the light source 60 is provided inside the sealing film 201 of the housing 200 and is configured to be able to irradiate light toward the detection object Fg attached to the ring-shaped housing 200. For example, an inorganic LED (Light Emitting Diode) or an organic EL (Organic Light Emitting Diode) is used as the light source 60. The light source 60 irradiates light of a predetermined wavelength. In this embodiment, the light source 60 has a plurality of light sources so as to be able to irradiate near-infrared light, red light, and green light.

[0020] Light emitted from the light source 60 is reflected by the surface of the detection object Fg and enters the first optical sensor 10A and the second optical sensor 10B. This allows the detection device 1 to detect a fingerprint by detecting the shape of the irregularities on the surface of the detection object Fg or the like. Alternatively, the light emitted from the light source 60 may be reflected inside the detection object Fg or may pass through the detection object Fg and enter the first optical sensor 10A and the second optical sensor 10B. This allows the detection device 1 to detect information about a living body inside a finger or the like. The information about the living body includes, for example, the pulse wave, pulse rate, and blood vessel image of the finger or palm. In other words, the detection device 1 may be configured as a fingerprint detection device that detects fingerprints or a vein detection device that detects blood vessel patterns such as veins.

[0021] Each of the first optical sensor 10A and the second optical sensor 10B detects light emitted by the light source 60 and reflected by the detection object Fg, directly incident light, etc. The first optical sensor 10A and the second optical sensor 10B are organic photodiodes (OPDs). The first optical sensor 10A is provided in the housing 200 so as to be adjacent to one end 610 of the light source 60 in the circumferential direction 200C of the housing 200. The second optical sensor 10B is provided in the housing 200 so as to be adjacent to the other end 620 of the light source 60 in the circumferential direction 200C of the housing 200.

[0022] As shown in Fig. 3, the first optical sensor 10A and the second optical sensor 10B each have a photodiode PD (see Fig. 4), which is an organic photodiode. Each of the first optical sensor 10A and the second optical sensor 10B has two lower electrodes 11 aligned along the circumferential direction 200C. The first optical sensor 10A and the second optical sensor 10B are mounted on a single first substrate 21 and electrically connected to the flexible printed circuit board 70 via the first substrate 21. The first substrate 21 has a cutout portion 22 (see Fig. 4) between the first optical sensor 10A and the second optical sensor 10B in the circumferential direction 200C of the housing 200.

[0023] In the following description, the first direction Dx is a direction in a plane parallel to the first substrate 21 and is the same direction as the circumferential direction 200C. The second direction Dy is a direction in a plane parallel to the first substrate 21 and is a direction perpendicular to the first direction Dx. The second direction Dy may intersect with the first direction Dx without being perpendicular thereto. The third direction Dz is a direction perpendicular to the first direction Dx and the second direction Dy. The third direction Dz is the normal direction of the first substrate 21. Furthermore, "planar view" refers to the positional relationship when viewed from a direction perpendicular to the first substrate 21.

[0024] 4, the first optical sensor 10A has a configuration in which two lower electrodes 11 aligned in the first direction Dx and one upper electrode 15A are stacked. The second optical sensor 10B has a configuration in which two lower electrodes 11 aligned in the first direction Dx and one upper electrode 15B are stacked. The upper electrode 15 includes the upper electrode 15A of the first optical sensor 10A and the upper electrode 15B of the second optical sensor 10B. Each of the upper electrode 15A and the upper electrode 15B covers two lower electrodes 11 in a plan view.

[0025] The first substrate 21 has a power supply electrode 211 extending in the second direction Dy. The power supply electrode 211 is electrically connected to a connection portion 212 (terminal portion) of the first substrate 21, and a sensor power supply signal is supplied from the power supply circuit 123 (see FIG. 3 ) via the connection portion 212. The upper electrode 15 is electrically connected to the power supply electrode 211 by a conductive material 213. The conductive material 213 is provided on the first substrate 21 so as to straddle the upper electrode 15 and the power supply electrode 211, and is made of a conductive material. As a result, the sensor power supply signal is supplied to the upper electrode 15 from the power supply circuit 123 via the power supply electrode 211.

[0026] The plurality of first wirings 26 of the first substrate 21 are connected to a detection circuit 48 included in the control circuit 122 via a plurality of signal lines SL of the flexible printed circuit board 70. The detection circuit 48 is electrically connected to the lower electrodes 11 of the first optical sensor 10A and the second optical sensor 10B via the plurality of signal lines SL. The detection circuit 48 may be formed as a circuit separate from the control circuit 122.

[0027] The first wiring 26 is formed, for example, of a metal wiring, and is formed of a material having better conductivity than the lower electrode 11 of the photodiode PD. The first wiring 26 is formed, for example, of a light-transmitting conductive material such as ITO (Indium Tin Oxide). The first wiring 26 is provided in a layer between the first substrate 21 and the photodiode PD in the third direction Dz. The first wiring 26 is electrically connected to the lower electrode 11 and the connection portion 212 on the first substrate 21. Note that the first wiring 26 may be formed, for example, in the same layer as the lower electrode 11, or may be formed of metal.

[0028] The second wiring 260 is electrically connected to the power supply electrode 211 by a conductive material 213. The second wiring 260 is formed, for example, of a metal wiring and is formed of a material having conductivity. The second wiring 260 is formed of a material having better conductivity than the upper electrode 15. The second wiring 260 is provided in a layer between the first substrate 21 and the photodiode PD in the third direction Dz. The second wiring 260 is electrically connected to the upper electrode 15 and the connection portion 212. Note that the second wiring 260 may be formed, for example, in the same layer as the upper electrode 15 or may be formed of metal. The second wiring 260 may also be a shield layer.

[0029] The control circuit 122 is a circuit that supplies control signals to the multiple photodiodes PD to control the detection operation. The multiple photodiodes PD output electrical signals corresponding to the light irradiated thereon as detection signals Vdet to the detection circuit 48. The second wiring 260 is connected to the control circuit 122 via wiring 261 that supplies a power supply voltage to the second wiring 260. In this embodiment, the detection signals Vdet of the multiple photodiodes PD are output to the detection circuit 48 sequentially in a time-division manner. In other words, the multiple signal lines SL are electrically connected to the detection circuit 48 sequentially in a time-division manner. As a result, the detection device 1 detects information about the object to be detected Fg based on the detection signals Vdet from the multiple photodiodes PD.

[0030] 5 , the first optical sensor 10A has a first substrate 21 (first region 21A), a photodiode PD, and a second substrate 50 facing the first substrate 21. In the present embodiment, the first optical sensor 10A further has a first insulating layer 27 and a second insulating layer 270.

[0031] The first insulating layer 27 is provided on the first substrate 21. The first insulating layer 27 is disposed between the first substrate 21 and the photodiode PD. The second insulating layer 270 is provided on the photodiode PD. The second insulating layer 270 is disposed between the second substrate 50 and the photodiode PD. The first insulating layer 27 and the second insulating layer 270 may be inorganic insulating films or organic insulating films.

[0032] The photodiodes PD are provided on the first insulating layer 27. The photodiodes PD have a lower electrode 11, a lower buffer layer 12, an active layer 13, an upper buffer layer 14, and an upper electrode 15 (15A). The photodiodes PD are formed by stacking the lower electrode 11, the lower buffer layer 12 (hole transport layer), the active layer 13, the upper buffer layer 14 (electron transport layer), the upper electrode 15, and the light-shielding layer 39 in this order in a third direction Dz perpendicular to the first substrate 21. The lower buffer layer 12, the active layer 13, the upper buffer layer 14, and the lower electrode 11 are arranged separately for each of the multiple photodiodes PD.

[0033] The lower electrode 11 is an anode electrode of the photodiode PD, and is made of a light-transmitting conductive material such as ITO (Indium Tin Oxide).

[0034] The active layer 13 changes its characteristics (e.g., voltage-current characteristics and resistance value) depending on the light irradiated thereto. An organic material is used as the material for the active layer 13. Specifically, the active layer 13 has a bulk heterostructure in which a p-type organic semiconductor and an n-type organic semiconductor, an n-type fullerene derivative (PCBM), are mixed. Examples of low-molecular-weight organic materials that can be used for the active layer 13 include C60 (fullerene), PCBM (phenyl C61-butyric acid methyl ester), CuPc (copper phthalocyanine), F16CuPc (fluorinated copper phthalocyanine), rubrene (5,6,11,12-tetraphenyltetracene), and PDI (perylene derivative).

[0035] The active layer 13 can be formed using these low-molecular-weight organic materials by a vapor deposition (dry process). In this case, the active layer 13 may be, for example, a laminated film of CuPc and F16CuPc, or a laminated film of rubrene and C60. The active layer 13 can also be formed by a coating (wet process). In this case, the active layer 13 is made of a material that combines the above-mentioned low-molecular-weight organic material with a high-molecular-weight organic material. Examples of high-molecular-weight organic materials that can be used include P3HT (poly(3-hexylthiophene)) and F8BT (F8-alt-benzothiadiazole). The active layer 13 can be a film in which P3HT and PCBM are mixed, or a film in which F8BT and PDI are mixed.

[0036] The lower buffer layer 12 is a hole transport layer. The upper buffer layer 14 is an electron transport layer. The lower buffer layer 12 and the upper buffer layer 14 are provided to facilitate the holes and electrons generated in the active layer 13 to reach the lower electrode 11 or the upper electrode 15. The lower buffer layer 12 (hole transport layer) is in direct contact with the lower electrode 11, and is also provided in the region between adjacent lower electrodes 11. The active layer 13 is in direct contact with the lower buffer layer 12. The material of the hole transport layer is a metal oxide layer. As the metal oxide layer, tungsten oxide (WO ３), molybdenum oxide, etc. are used.

[0037] The upper buffer layer 14 (electron transport layer) is in direct contact with the active layer 13, and the upper electrode 15 is in direct contact with the upper buffer layer 14. Ethoxylated polyethyleneimine (PEIE) is used as the material for the electron transport layer.

[0038] The materials and manufacturing methods of the lower buffer layer 12, the active layer 13, and the upper buffer layer 14 are merely examples, and other materials and manufacturing methods may be used. For example, the lower buffer layer 12 and the upper buffer layer 14 are not limited to single-layer films, and may be formed as multilayer films including an electron blocking layer and a hole blocking layer.

[0039] The upper electrode 15 is provided on the upper buffer layer 14. The upper electrode 15 is a cathode electrode of the photodiode PD and is continuously formed across the entire first photosensor 10A and the second photosensor 10B. In other words, the upper electrode 15 is continuously provided on the multiple photodiodes PD. The upper electrode 15 faces the multiple lower electrodes 11, sandwiching the lower buffer layer 12, the active layer 13, and the upper buffer layer 14 between them. The upper electrode 15 is formed of a light-transmitting conductive material such as ITO or IZO. The upper electrode 15 may also be a laminated film of multiple light-transmitting conductive materials. A portion of the edge of the upper surface 150 of the upper electrode 15 is electrically connected to the conductive material 213. In the first photosensor 10A, the photodiode PD is effectively sealed by providing a sealing film 201 on the upper electrode 15 and the like. The upper electrode 15 is provided on the upper buffer layer 14, spanning adjacent photodiodes PD.

[0040] 4 and 5 , the light-shielding layer 39 is provided in the third direction Dz between the first substrate 21 and the first insulating layer 27 at a position overlapping the outer peripheral edge of the upper electrode 15 for each photodiode PD. The light-shielding layer 39 is provided in a region overlapping the edge of the lower buffer layer 12, the edge of the active layer 13, the edge of the upper buffer layer 14, and the edge of the lower electrode 11 in a plan view. The light-shielding layer 39 is formed of a non-light-transmitting material. The light-shielding layer 39 is provided to cover the edge of the upper electrode 15.

[0041] An opening OP is formed in the light-shielding layer 39 in a region overlapping with the lower electrode 11 .

[0042] The second optical sensor 10B has two adjacent lower electrodes 11 in a second region 21B of the first substrate 21, which is different from the lower electrodes 11 of the first optical sensor 10A. The second optical sensor 10B has a first substrate 21 (second region 21B), a photodiode PD, a first insulating layer 27, a second substrate 50 facing the first substrate 21, and a second insulating layer 270. The second substrate 50, photodiode PD, first insulating layer 27, and second insulating layer 270 have the same configuration as the photodiode PD and first insulating layer 27 of the first optical sensor 10A. That is, the photodiode PD of the second optical sensor 10B has a lower electrode 11, a lower buffer layer 12, an active layer 13, an upper buffer layer 14, and an upper electrode 15 (15B). In this embodiment, the first optical sensor 10A and the second optical sensor 10B are organic photodiodes.

[0043] 4, the first substrate 21 has the first region 21A of the first optical sensor 10A and the second region 21B of the second optical sensor 10B, and is formed integrally as a single common substrate. The first substrate 21 has a cutout portion 22 formed in the first direction Dx between the first region 21A of the first optical sensor 10A and the second region 21B of the second optical sensor 10B. The first substrate 21 has the cutout portion 22 between the first optical sensor 10A and the second optical sensor 10B.

[0044] The cutout portion 22 is formed in the first direction Dx by a distance D1 that is longer than the length of the light source 60. The cutout portion 22 is formed in the second direction Dy by a distance D2 that is longer than the length of the light source 60 and shorter than the length (width) of the first substrate 21. The cutout portion 22 is formed such that the distance between a center 22C of the cutout portion 22 and one side of the lower electrode 11 of the first optical sensor 10A and one side of the lower electrode 11 of the second optical sensor 10B is equal in the first direction Dx. In the first embodiment, the cutout portion 22 is formed in a substantially rectangular shape in a plan view, but may be, for example, a semicircular, triangular, polygonal, or other shape.

[0045] When the detection device 1 is a bottom-receiving type photosensor, the lower buffer layer 12 is an electron transport layer, and the upper buffer layer 14 is a hole transport layer. When the detection device 1 is a top-receiving type photosensor, the lower buffer layer 12 is a hole transport layer, and the upper buffer layer 14 is an electron transport layer. The active layer 13 is in direct contact with the lower buffer layer 12. The material of the hole transport layer is a metal oxide layer. As the metal oxide layer, tungsten oxide (WO ３ ), molybdenum oxide, etc. are used.

[0046] 6 and 7 are timing waveform diagrams showing the optical response characteristics of a detection device according to a comparative example. The light-shielding layer 39 is not provided in the structure of the comparative example.

[0047] 6 and 7, a detection operation using the first light is performed in periods t(1) and t(3), and a detection operation using the second light is performed in periods t(2) and t(4). Hereinafter, the periods t(1) and t(3) in which the detection operation using the first light is performed will also be referred to as the "first light detection period," and the periods t(2) and t(4) in which the detection operation using the second light is performed will also be referred to as the "second light detection period."

[0048] The first light is near-infrared light and green light, and the second light is red light. When a detection operation using the first light is performed, photoresponsive components T1 and T3 of carriers (holes and electrons) are generated by the active layer 31. When a detection operation using the second light is performed, photoresponsive components T2 and T4 of carriers (holes and electrons) are generated by the active layer 31.

[0049] If the light-shielding layer 39 is not provided at the end of the lower electrode 11 of the detection device according to the comparative example, after the first light or the second light is detected, a response delay component of the first light or the second light remains in the next detection period, resulting in a mixed detection of the first light and the second light, as shown in Fig. 6. As such, if the light-shielding layer 39 is not provided, carriers (holes and electrons) generated in the active layer 31 in the region overlapping with the end of the lower electrode 11 may experience a delay in the optical response until they reach the lower electrode 11, compared to carriers (holes and electrons) generated in the active layer 31 in the region not overlapping with the end of the lower electrode 11.

[0050] In contrast, in the first embodiment in which the light-shielding layer 39 is provided at the end of the lower electrode 11 of the detection device 1, the end of the lower electrode 11 is light-shielded, so that the peak of the photoresponse output is smaller than the peak of the photoresponse output shown in Fig. 6, as shown in Fig. 7. As a result, after the first light or the second light is detected, no response delay component of the first light or the second light remains in the next detection period, and does not affect the photoresponse component of the first light or the second light.

[0051] The detection device 1 of this embodiment is configured as a bottom-light-receiving optical sensor. That is, light L1 emitted from the light source 60 (see FIG. 2 ) and transmitted through or reflected by the object to be detected Fg passes through the first substrate 21 and is irradiated onto the lower electrode 11 side of the photodiode PD. The light L1 passes through the opening OP in the light-shielding layer 39 and is irradiated onto the active layer 13 of the photodiode PD. Carriers (holes and electrons) generated in the active layer 13 pass through the lower buffer layer 12 and upper buffer layer 14 to reach the lower electrode 11 and upper electrode 15, respectively.

[0052] In the detection device 1, light L1 is blocked in the region overlapping with the light-shielding layer 39, and is not irradiated onto the active layer 13 located in the region overlapping with the light-shielding layer 39. This suppresses the generation of carriers (holes and electrons) in the portion of the active layer 13 that overlaps with the light-shielding layer 39 (the portion that overlaps with the region of the outer periphery of the lower electrode 11). Therefore, it is possible to suppress the delay in the arrival time of carriers (holes and electrons) generated in the active layer 31 between the portion that overlaps with the outer periphery of the lower electrode 11 of the photodiode PD and the portion that does not overlap with the outer periphery of the lower electrode 11 of the photodiode PD. As a result, the detection device 1 having the OPD can improve detection accuracy.

[0053] The above describes an example of the configuration of the detection device 1 according to this embodiment. Note that the configuration described above using Figures 1 to 5 is merely an example, and the configuration of the detection device 1 according to this embodiment is not limited to this example. The configuration of the detection device 1 according to this embodiment can be flexibly modified depending on the specifications and operation.

[0054] 8 is a cross-sectional schematic diagram showing an example of a stacked configuration of an optical sensor of a detection device according to Modification 1 of Embodiment 1. In the following description, the same components as those described in the above-described embodiment are denoted by the same reference numerals, and redundant description will be omitted.

[0055] As shown in FIG. 8, in a detection device 1A according to the first modification of the first embodiment, a light-shielding layer 39A is provided on the outer periphery of the upper electrode 15 for each photodiode PD.

[0056] The detection device 1A is configured as a top-light-receiving optical sensor. That is, light L1 emitted from a light source 60 (see FIG. 2 ) and transmitted through or reflected by the object to be detected Fg passes through the first insulating layer 27 and is irradiated onto the upper electrode 15 side of the photodiode PD. The light L1 passes through an opening OP in the light-shielding layer 39A and is irradiated onto the active layer 13 of the photodiode PD. Carriers (holes and electrons) generated in the active layer 13 pass through the lower buffer layer 12 and upper buffer layer 14 to reach the lower electrode 11 and upper electrode 15, respectively.

[0057] In the detection device 1A, too, the light L1 is blocked in the region overlapping with the light-shielding layer 39A, and is not irradiated onto the portion of the active layer 13 that overlaps with the light-shielding layer 39A. This suppresses the generation of carriers (holes and electrons) in the portion of the active layer 13 that overlaps with the light-shielding layer 39A (the portion that overlaps with the region of the outer periphery of the lower electrode 11). As a result, the detection device 1A having an OPD can improve detection accuracy.

[0058] (Modification 2 of First Embodiment) Fig. 9 is a development view showing an example of development of optical sensors of a detection device according to Modification 2 of the first embodiment. Fig. 10 is a configuration diagram showing an example of the configuration of the first optical sensor and the second optical sensor shown in Fig. 9. In the following description, the same components as those described in the above-mentioned embodiment are denoted by the same reference numerals, and duplicated description will be omitted.

[0059] 9 , the number of optical sensor elements in the detection device 1B is two. A flexible printed circuit board 70 electrically connects the light source 60, the first optical sensor 10A, etc. to the control circuit 122. In the detection device 1B, the first optical sensor 10A and the light source 60 are arranged side by side in the circumferential direction 200C in this order. The first optical sensor 10A is arranged near one end of the light source 60 in the circumferential direction 200C, thereby enabling the first optical sensor 10A to detect light emitted by the light source 60 over a wide range of the housing 200.

[0060] The first substrate 21 is attached to the flexible printed circuit board 70, thereby positioning the first optical sensor 10A near one end of the light source 60 in the circumferential direction 200C of the housing 200. The first substrate 21 has a first region 21A where the first optical sensor 10A is mounted. The first substrate 21 is formed as a single substrate having the first region 21A.

[0061] 10 , the first optical sensor 10A has a stacked configuration of two lower electrodes 11 and one upper electrode 15A aligned in the first direction Dx. The upper electrode 15 includes the upper electrode 15A of the first optical sensor 10A. The upper electrode 15A covers the two lower electrodes 11 in a plan view.

[0062] 11 is a plan view schematically illustrating a detection device according to a second embodiment. In the following description, the same components as those described in the above-described embodiment are denoted by the same reference numerals, and redundant description will be omitted.

[0063] 11 , the detection device 1C includes a sensor substrate 210 (substrate), a sensor unit 10, a gate line driving circuit 16, a signal line selection circuit 17, a detection circuit 48, a control circuit 122, a power supply circuit 123, a first light source substrate 51, a second light source substrate 52, and light sources 53 and 54. The first light source substrate 51 is provided with a plurality of light sources 53. The second light source substrate 52 is provided with a plurality of light sources 54.

[0064] The control board 121 is electrically connected to the sensor substrate 210 via a wiring board 71. The wiring board 71 is, for example, a flexible printed circuit board or a rigid board. The wiring board 71 is provided with a detection circuit 48. The control board 121 is provided with a control circuit 122 and a power supply circuit 123. The control circuit 122 is, for example, an FPGA (Field Programmable Gate Array). The control circuit 122 supplies control signals to the sensor unit 10, the gate line driving circuit 16, and the signal line selection circuit 17 to control the detection operation of the sensor unit 10. The control circuit 122 also supplies control signals to the light sources 53 and 54 to control the lighting or non-lighting of the light sources 53 and 54. The power supply circuit 123 supplies voltage signals such as a sensor power supply signal VDDSNS (see FIG. 13 ) to the sensor unit 10, the gate line driving circuit 16, and the signal line selection circuit 17. Furthermore, the power supply circuit 123 supplies a power supply voltage to the light sources 53 and 54 .

[0065] The sensor substrate 210 has a detection area AA and a peripheral area GA. The detection area AA is an area where multiple photodiodes PD (see FIG. 14 ) of the sensor unit 10 are provided. The peripheral area GA is an area between the outer periphery of the detection area AA and the outer edge of the sensor substrate 210, and is an area where multiple photodiodes PD are not provided.

[0066] The gate line driving circuit 16 and the signal line selection circuit 17 are provided in the peripheral area GA. Specifically, the gate line driving circuit 16 is provided in a region of the peripheral area GA extending along the second direction Dy. The signal line selection circuit 17 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.

[0067] In the following description, the first direction Dx is a direction in a plane parallel to the sensor substrate 210. The second direction Dy is a direction in a plane parallel to the sensor substrate 210, 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 the normal direction to the main surface of the sensor substrate 210. Furthermore, "planar view" refers to the positional relationship when viewed from a direction perpendicular to the sensor substrate 210.

[0068] The plurality of light sources 53 are provided on the first light source substrate 51 and arranged along the second direction Dy. The plurality of light sources 54 are provided on the second light source substrate 52 and arranged along the second direction Dy. The first light source substrate 51 and the second light source substrate 52 are electrically connected to the control circuit 122 and the power supply circuit 123 via terminal portions 124 and 125 provided on the control board 121, respectively.

[0069] For example, inorganic light emitting diodes (LEDs) or organic light emitting diodes (OLEDs) are used as the light sources 53 and 54. The light sources 53 and 54 emit light of different wavelengths.

[0070] Light emitted from the light source 53 is reflected by the surface of the detection object Fg and enters the sensor unit 10. As a result, the sensor unit 10 can detect a fingerprint by detecting the uneven shape of the surface of a finger or the like. Light emitted from the light source 54 is reflected inside the detection object Fg or passes through the detection object Fg and enters the sensor unit 10. As a result, the sensor unit 10 can detect information about the living body inside the finger or the like. The information about the living body includes, for example, the pulse wave, pulse rate, blood vessel image, etc. of the finger or palm. In other words, the detection device 1 may be configured as a fingerprint detection device that detects fingerprints, or a vein detection device that detects blood vessel patterns such as veins.

[0071] The arrangement of the light sources 53, 54 shown in Figure 11 is merely an example and can be changed as appropriate. The detection device 1 is provided with multiple types of light sources 53, 54 as light sources. However, this is not limited to this, and the light source may be of one type. For example, multiple light sources 53 and multiple light sources 54 may be arranged on each of the first light source substrate 51 and the second light source substrate 52. Furthermore, the number of light source substrates on which the light sources 53 and the light sources 54 are arranged may be one or three or more. Alternatively, it is sufficient that at least one or more light sources are arranged.

[0072] Fig. 12 is a block diagram showing an example of the configuration of a detection device according to the second embodiment. As shown in Fig. 12, the detection device 1C further includes a detection control circuit 110 and a detection unit 40. Some or all of the functions of the detection control circuit 110 are included in a control circuit 122. 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 122.

[0073] The sensor unit 10 has a plurality of photodiodes PD. The photodiodes PD of the sensor unit 10 output electrical signals corresponding to the incident light as detection signals Vdet to the signal line selection circuit 17. The sensor unit 10 also performs detection in accordance with the gate drive signal VGL supplied from the gate line drive circuit 16.

[0074] The detection control circuit 110 supplies control signals to the gate line drive circuit 16, the signal line selection circuit 17, and the detection unit 40, respectively, to control their operations. The detection control circuit 110 supplies various control signals, such as a start signal STV and a clock signal CK, to the gate line drive circuit 16. The detection control circuit 110 also supplies various control signals, such as a selection signal ASW, to the signal line selection circuit 17. The detection control circuit 110 also supplies various control signals to the light sources 53 and 54 to control their lighting and non-lighting.

[0075] The gate line driving circuit 16 drives a plurality of gate lines GL (see FIG. 3) based on various control signals. The gate line driving circuit 16 sequentially or simultaneously selects the plurality of gate lines GL and supplies a gate driving signal VGL to the selected gate lines GL. In this way, the gate line driving circuit 16 selects a plurality of photodiodes PD connected to the gate lines GL.

[0076] The signal line selection circuit 17 has a switch circuit that sequentially or simultaneously selects multiple signal lines SL (see FIG. 13 ). The signal line selection circuit 17 is, for example, a multiplexer. The signal line selection circuit 17 connects the selected signal line SL to the detection circuit 48 based on a selection signal ASW supplied from the detection control circuit 110. As a result, the signal line selection circuit 17 outputs a detection signal Vdet of the photodiode PD to the detection unit 40.

[0077] 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 110 so that they operate in synchronization with each other.

[0078] 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 amplifies the detection signal Vdet. The A / D conversion circuit 43 converts the analog signal output from the detection signal amplifier circuit 42 into a digital signal.

[0079] The signal processing circuit 44 detects a predetermined physical quantity input to the sensor unit 10 based on the output signal of the detection circuit 48. The signal processing circuit 44 is a logic circuit. When the object to be detected Fg comes into contact with or close to the detection surface, the signal processing circuit 44 can detect unevenness on the surface of the finger or palm based on the signal from the detection circuit 48. The signal processing circuit 44 can also detect information about the living body based on the signal from the detection circuit 48. The information about the living body includes, for example, an image of the blood vessels of the finger or palm, a pulse wave, a pulse rate, and a blood oxygen concentration.

[0080] 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.

[0081] When the signal processing circuit 44 detects contact or proximity of the object Fg to be detected, the coordinate extraction circuit 45 determines the detection coordinates of the unevenness of the surface of the finger or the like. The coordinate extraction circuit 45 also determines the detection coordinates of the blood vessels in the finger or palm. The coordinate extraction circuit 45 is a logic circuit. The coordinate extraction circuit 45 combines the detection signals Vdet output from each photodiode PD of the sensor unit 10 to generate two-dimensional information indicating the shape of the unevenness of the surface of the finger or the like and two-dimensional information indicating the shape of the blood vessels in the finger or palm. The coordinate extraction circuit 45 may output the detection signal Vdet as the sensor output voltage Vo without calculating the detection coordinates.

[0082] Fig. 13 is a circuit diagram showing a detection device according to the second embodiment. Fig. 13 also shows the circuit configuration of a detection circuit 48. As shown in Fig. 13, a sensor pixel PX includes a photodiode PD, a capacitance element Ca, and a drive transistor Tr. The capacitance element Ca is a capacitance (sensor capacitance) formed in the photodiode PD, and is equivalently connected in parallel with the photodiode PD.

[0083] 13 shows two gate lines GL(m) and GL(m+1) aligned in the second direction Dy among the multiple gate lines GL. Also, two signal lines SL(n) and SL(n+1) aligned in the first direction Dx among the multiple signal lines SL. A sensor pixel PX is an area surrounded by the gate line GL and the signal line SL.

[0084] The drive transistors Tr are provided corresponding to the respective photodiodes PD. The drive transistors Tr are configured by thin film transistors, and in this example, are configured by n-channel MOS (Metal Oxide Semiconductor) type TFTs (Thin Film Transistors).

[0085] Each of the gate lines GL is connected to the gates of a plurality of drive transistors Tr arranged in a first direction Dx. Each of the signal lines SL is connected to one of the source and drain of a plurality of drive transistors Tr arranged in a second direction Dy. The other of the source and drain of each of the drive transistors Tr is connected to the anode of the photodiode PD and the capacitance element Ca.

[0086] A sensor power supply signal VDDSNS is supplied to the cathode of the photodiode PD from a power supply circuit 123 (see FIG. 11 ). A sensor reference voltage COM, which serves as the initial potential of the signal line SL and the capacitance element Ca, is supplied to the signal line SL and the capacitance element Ca from the power supply circuit 123 via a reset transistor TrR.

[0087] When light is irradiated onto the sensor pixel PX during the exposure period, a current corresponding to the amount of light flows through the photodiode PD, causing charge to accumulate in the capacitance element Ca. When the drive transistor Tr is turned on during the readout period, a current corresponding to the charge accumulated in the capacitance element Ca flows through the signal line SL. The signal line SL is connected to the detection circuit 48 via the output transistor TrS of the signal line selection circuit 17. This allows the detection device 1 to detect a signal corresponding to the amount of light irradiated onto the photodiode PD for each sensor pixel PX.

[0088] During the readout period, the switch SSW of the detection circuit 48 is turned on and connected to the signal line SL. The detection signal amplifier circuit 42 of the detection circuit 48 converts the current or charge supplied from the signal line SL into a voltage corresponding to the current or charge. A reference potential (Vref) having a fixed potential is input to the non-inverting input terminal (+) of the detection signal amplifier circuit 42, and the signal line SL is connected to the inverting input terminal (-). In this embodiment, a signal equal to the sensor reference voltage COM is input as the reference potential (Vref) voltage. The control circuit 122 (see FIG. 11) calculates the difference between the detection signal Vdet when light is irradiated and the detection signal Vdet when light is not irradiated as the sensor output voltage Vo. The detection signal amplifier circuit 42 also includes a capacitance element Cb and a reset switch RSW. During the reset period, the reset switch RSW is turned on, resetting the charge in the capacitance element Cb.

[0089] The driving transistor Tr is not limited to an n-type TFT, but may be a p-type TFT. The pixel circuit of the sensor pixel PX shown in Fig. 3 is merely an example, and the sensor pixel PX may be provided with multiple transistors corresponding to one photodiode PD.

[0090] Next, the configuration of the photodiode PD will be described. Fig. 14 is an enlarged schematic configuration diagram of a sensor unit according to the second embodiment. Fig. 15 is a plan view showing a light-shielding layer according to the second embodiment. Fig. 14 is a plan view showing a part of the sensor unit 10, and is a plan view in which the light-shielding layer 36 in Fig. 15 is removed. In Fig. 15, the light-shielding layer 36 is shown hatched.

[0091] 14 and 15 , the detection device 1C has a plurality of photodiodes PD provided on a sensor substrate 210 and a light-shielding layer 36. A plurality of gate lines GL each extend in a first direction Dx and are arranged at intervals in a second direction Dy. A plurality of signal lines SL each extend in the second direction Dy and are arranged at intervals in the first direction Dx. The plurality of photodiodes PD are provided in an area surrounded by two gate lines GL and two signal lines SL, and are arranged in a matrix on the sensor substrate 210.

[0092] Furthermore, lower electrodes 23 of the photodiodes PD are provided in a matrix on the sensor substrate 210 in correspondence with each of the multiple photodiodes PD. As shown in Fig. 14, the lower electrodes 23 have a first side 23a and a second side 23b intersecting with the first side 23a. The first side 23a and the second side 23b are disposed at intervals from the signal lines SL and the gate lines GL, respectively.

[0093] The drive transistor Tr is provided in a region overlapping with the lower electrode 23 of the photodiode PD. Specifically, the drive transistor Tr has a semiconductor layer 61, a source electrode 62, a drain electrode 63, and a gate electrode 64. The semiconductor layer 61 extends along the gate line GL and is provided so as to intersect with the gate electrode 64 in a plan view. The gate electrode 64 is connected to the gate line GL and extends in a direction (second direction Dy) perpendicular to the gate line GL.

[0094] 15, the light-shielding layer 36 is provided in a region overlapping with the first side 23a and the second side 23b of the lower electrode 23 in a plan view. The light-shielding layer 36 is not provided in a region overlapping with the drive transistor Tr.

[0095] More specifically, the light-shielding layer 36 has first light-shielding portions 36a and second light-shielding portions 36b. The light-shielding layer 36 is formed in a lattice pattern with the first light-shielding portions 36a and the second light-shielding portions 36b intersecting with each other. The first light-shielding portions 36a extend in the second direction Dy. The first light-shielding portions 36a overlap with the first side 23a of the lower electrode 23 and extend along the first side 23a of the lower electrode 23. The second light-shielding portions 36b extend in the first direction Dx. The second light-shielding portions 36b overlap with the second side 23b of the lower electrode 23 and extend along the second side 23b of the lower electrode 23.

[0096] 15, an opening OP is formed in the light-shielding layer 36 in a region overlapping the opening of the insulating film 35. The opening OP of the light-shielding layer 36 is a region surrounded by two first light-shielding portions 36a and two second light-shielding portions 36b.

[0097] The shapes, arrangement pitches, etc. of the lower electrodes 23 and the light-shielding layers 36 shown in FIGS. 14 and 15 are merely examples, and can be changed as appropriate depending on the characteristics and detection accuracy required for the detection device 1C.

[0098] Figure 16 is a cross-sectional view taken along the line XVI-XVI' in Figure 15. As shown in Figure 16, the detection device 1C includes a circuit formation layer 29, a light-shielding layer 36, an insulating film 28 (organic insulating film), a photodiode PD, and a sealing film 90 stacked in this order on a sensor substrate 210. The sensor substrate 210 is an insulating substrate, and for example, a glass substrate such as quartz or alkali-free glass is used. The sensor substrate 210 is not limited to being flat, and may have a curved surface. In this case, the sensor substrate 210 may be made of a film-like resin material.

[0099] The circuit formation layer 29 is provided on the sensor substrate 210, and is a layer on which various transistors such as the drive transistors Tr shown in Figures 13 and 14, and various wirings such as the gate lines GL and signal lines SL are formed. Figure 6 illustrates the signal lines SL connected to the drive transistors Tr, part of the circuit formation layer 29. The insulating film 28 is provided on the circuit formation layer 29 including the drive transistors Tr, covering the signal lines SL. The insulating film 28 is an organic planarizing film made of an organic insulating material.

[0100] The photodiode PD is provided on the insulating film 28. More specifically, the photodiode PD has a lower electrode 23, a lower buffer layer 32, an active layer 31, an upper buffer layer 33, and an upper electrode 24. In the photodiode PD, the lower electrode 23, the lower buffer layer 32, the active layer 31, the upper buffer layer 33, and the upper electrode 24 are stacked in this order in a direction perpendicular to the sensor substrate 210. The photodiode PD of this embodiment is an OPD (organic photodiode) in which an organic semiconductor is used as the active layer 31.

[0101] The lower buffer layer 32, the active layer 31, the upper buffer layer 33 and the lower electrode 23 are arranged separately for each of the plurality of photodiodes PD.

[0102] The components and materials of the upper electrode 24, upper buffer layer 33, active layer 31, lower buffer layer 32, and lower electrode 23 are almost the same as those of the upper electrode 15, upper buffer layer 14, active layer 13, lower buffer layer 12, and lower electrode 11 of the conveying device 1 according to the first embodiment, respectively, and therefore will not be described here.

[0103] The light-shielding layer 36 (first light-shielding portion 36a) is a metal layer or an alloy layer provided in the same layer as the signal line SL, the source electrode 62, and the drain electrode 63. The light-shielding layer 36 is provided in regions overlapping with the end of the lower buffer layer 32, the end of the active layer 31, and the end of the upper buffer layer 33, and in a region overlapping with the peripheral edge of the lower electrode 23.

[0104] Furthermore, contact hole CH1 is provided in the center of lower electrode 23, penetrating insulating film 28 in the thickness direction (third direction Dz). Lower electrode 23 is connected to connection pad 66 at the bottom of contact hole CH1. Lower electrode 23 is provided to cover the bottom of contact hole CH1, and is electrically connected to connection pad 66 at the bottom of contact hole CH1.

[0105] The lower buffer layer 32 and the upper buffer layer 33 are provided to allow holes and electrons generated in the active layer 31 to easily reach the lower electrode 23 or the upper electrode 24. The lower buffer layer 32 is in direct contact with the lower electrode 23. The end of the photodiode PD is provided so as to overlap the light-shielding layer 36.

[0106] The active layer 31 is in direct contact with the upper surface of the lower buffer layer 32. The upper buffer layer 33 is in direct contact with the upper surface of the active layer 31, and the upper electrode 24 is in direct contact with the upper buffer layer 33.

[0107] The upper electrode 24 is provided on the upper buffer layer 33. The upper electrode 24 is a cathode electrode of the photodiode PD and is formed continuously over the entire detection area AA. In other words, the upper electrode 24 is provided continuously over the multiple photodiodes PD. The upper electrode 24 faces the multiple lower electrodes 23, with the lower buffer layer 32, the active layer 31, and the upper buffer layer 33 sandwiched between them.

[0108] The sealing film 90 is provided on the upper electrode 24. The sealing film 90 is made of an inorganic film such as a silicon nitride film or an aluminum oxide film, or a resin film such as acrylic. The sealing film 90 is not limited to a single layer, but may be a laminated film of two or more layers combining the inorganic film and the resin film. The sealing film 90 effectively seals the photodiode PD and can prevent moisture from entering from the upper surface side.

[0109] Fig. 17 is a cross-sectional view taken along the line XVII-XVII' of Fig. 15. As shown in Fig. 17, the detection device 1C has an insulating film 38, a light-shielding layer 360, an insulating film 28 (organic insulating film), a photodiode PD, and a sealing film 90 laminated in this order on a sensor substrate 210.

[0110] The insulating film 38 includes a first insulating film 38 a, a second insulating film 38 b, a third insulating film 38 c, and a fourth insulating film 38 d. The insulating film 38 is stacked on the sensor substrate 210 in the following order: the first insulating film 38 a, the second insulating film 38 b, the third insulating film 38 c, and the fourth insulating film 38 d.

[0111] The first insulating film 38a is provided on the sensor substrate 210. The light-shielding layer 360 is provided on the first insulating film 38a. The light-shielding layer 360 is electrically connected to the gate electrode 64, and the light-shielding layer 360 may function as the gate electrode.

[0112] The second insulating film 38b is provided on the first insulating film 38a, covering the light-shielding layer 360. The semiconductor layer 61 is provided on the second insulating film 38b.

[0113] The third insulating film 38c is provided on the second insulating film 38b, covering the semiconductor layer 61. The gate electrode 64 is provided on the third insulating film 38c. The light-shielding layer 360 overlaps with the semiconductor layer 61 and the gate electrode 64 when viewed from the third direction Dz, and is provided in a layer different from the semiconductor layer 61 and the gate electrode 64.

[0114] The fourth insulating film 38d is provided on the third insulating film 38c, covering the gate electrode 64. The source electrode 62 is provided on one end of the semiconductor layer 61 on the fourth insulating film 38d. The drain electrode 63 is provided on the other end of the semiconductor layer 61 on the fourth insulating film 38d. The source electrode 62 faces the drain electrode 63 in the first direction Dx, with the gate electrode 64 sandwiched between them. The first insulating film 38a, the second insulating film 38b, the third insulating film 38c, and the fourth insulating film 38d are formed of a light-transmitting inorganic material such as silicon oxide or silicon nitride, for example.

[0115] The semiconductor layer 61 is made of, for example, polysilicon. However, the semiconductor layer 61 is not limited to this and may be made of a microcrystalline oxide semiconductor, an amorphous oxide semiconductor, low temperature polycrystalline silicon (LTPS), or the like.

[0116] One end of the semiconductor layer 61 is connected to a source electrode 62 via a contact hole CH2. The source electrode 62 is connected to a connection wiring 65 and a connection pad 66, and is drawn out to the center of the photodiode PD (lower electrode 23). The lower electrode 23 is connected to the connection pad 66 at its center via a contact hole CH1. With this configuration, the source electrode 62 of the drive transistor Tr is electrically connected to the photodiode PD. The other end of the semiconductor layer 61 is connected to a drain electrode 63 via a contact hole CH3. The drain electrode 63 is connected to a signal line SL.

[0117] The detection device 1C is configured as a bottom-light-receiving optical sensor. That is, light L1 is emitted from light sources 53, 54 (see FIG. 11 ) to the detection object Fg. The light L1 transmitted through or reflected by the detection object Fg passes through the sensor substrate 210 and is irradiated onto the lower electrode 23 side of the photodiode PD. The light L1 passes through the opening OP in the light-shielding layer 36 and is irradiated onto the active layer 31 of the photodiode PD. Carriers (holes and electrons) generated in the active layer 31 pass through the lower buffer layer 32 and upper buffer layer 33 to reach the lower electrode 23 and upper electrode 24, respectively.

[0118] Furthermore, the light L1 is blocked in the region overlapping with the light-shielding layer 36, and is not irradiated onto the active layer 31 located in the region overlapping with the light-shielding layer 36. More specifically, the light L1 is not irradiated onto portions overlapping with the end of the lower buffer layer 32, the end of the active layer 31, the end of the upper buffer layer 33, and the end of the lower electrode 23. This suppresses the generation of carriers (holes and electrons) in the portion of the active layer 31 overlapping with the light-shielding layer 36. As a result, the detection device 1 having an OPD can improve detection accuracy.

[0119] 18 is a plan view showing a light-shielding layer according to Modification 1 of Embodiment 2. In the following description, the same components as those described in the above-described embodiment are denoted by the same reference numerals, and redundant description will be omitted.

[0120] 15 is not provided, a light-shielding layer 360 may be provided at a position overlapping the outer peripheral edge of the lower electrode 23, the signal line SL, and the scanning line GL, as shown in Fig. 18. In this case, the light-shielding layer 360 is provided separately so as to overlap the source electrode 62, the drain electrode 63, and the gate electrode 64. Furthermore, the second light-shielding portion 360b is not provided at a position overlapping the light-shielding layer 360 overlapping the source electrode 62, the drain electrode 63, and the gate electrode 64, respectively, and the first light-shielding portion 360a extending along the signal line SL and the second light-shielding portion 360b extending along the scanning line GL.

[0121] (Modification 2 of Second Embodiment) Fig. 19 is a plan view showing a light-shielding layer according to Modification 2 of the second embodiment. The light-shielding layer according to Modification 2 is composed of two layers at different levels. In the following description, the same components as those described in the above-mentioned embodiment are denoted by the same reference numerals, and duplicated description will be omitted. As shown in Fig. 19, the light-shielding layer 36 shown in Fig. 15 and the light-shielding layer 360 shown in Fig. 18 may be stacked on top of each other so that the two layers overlap the outer periphery of the lower electrode 23, the entire drive transistor Tr, the signal line SL, and the scanning line GL.

[0122] In this case, in the first direction Dx, the second light-shielding portion 36b is provided so as to overlap the outer circumferential edge of the lower electrode 23. The second light-shielding portion 36b is in the same layer as the scanning line GL. Furthermore, in the second direction Dy, the first light-shielding portion 360a is provided so as to overlap the outer circumferential edge of the lower electrode 23. The first light-shielding portion 360a is provided so as to overlap the entire driving transistor Tr. The first light-shielding portion 360a is in the same layer as the signal line SL. This provides light shielding from the second light-shielding portion 36b, the first light-shielding portion 360a, and the entire driving transistor Tr without any gaps.

[0123] 14 to 19 are merely examples and can be modified as appropriate. For example, the upper electrode 24 may be the anode electrode of the photodiode PD, and the lower electrode 23 may be the cathode electrode of the photodiode PD.

[0124] (Variation 3 of Second Embodiment) Fig. 20 is a plan view showing a light-shielding layer according to Variation 3 of the second embodiment. Fig. 21 is a cross-sectional view taken along XXI-XXI' in Fig. 20. Fig. 22 is a cross-sectional view taken along XXII-XXII' in Fig. 20. In the following description, the same components as those described in the above-mentioned embodiments are designated by the same reference numerals, and duplicate description will be omitted.

[0125] 20 , in a detection device 1D according to Modification 3 of the second embodiment, a light-shielding layer 37 is provided in an area overlapping the first side 23 a and the second side 23 b of the lower electrode 23 and the drive transistor Tr in a plan view. The light-shielding layer 37 is also provided in an area overlapping the signal line SL and the scanning line GL. The detection device 1D does not have the light-shielding layer 36 of the detection device 1C according to the second embodiment.

[0126] More specifically, the light-shielding layer 37 has first light-shielding portions 37a and second light-shielding portions 37b. The light-shielding layer 37 is formed in a lattice pattern with the first light-shielding portions 37a and the second light-shielding portions 37b intersecting with each other. The first light-shielding portions 37a extend in the second direction Dy. The first light-shielding portions 37a overlap with the first side 23a of the lower electrode 23 and extend along the first side 23a of the lower electrode 23. The second light-shielding portions 37b extend in the first direction Dx. The second light-shielding portions 37b overlap with the second side 23b of the lower electrode 23 and extend along the second side 23b of the lower electrode 23.

[0127] An opening OP is formed in the light-shielding layer 37 in a region overlapping with the first side 23 a and the second side 23 b of the lower electrode 23. The opening OP in the light-shielding layer 37 is a region surrounded by two first light-shielding portions 37 a and two second light-shielding portions 37 b.

[0128] 21 , the light-shielding layer 37 is provided on the upper electrode 24. The light-shielding layer 37 is formed of a non-light-transmitting metal layer or alloy layer. The light-shielding layer 37 is in contact with the upper electrode 24 and has the same potential as the upper electrode 24. In the detection device 1D, the light-shielding layer 37 is provided to cover the inclined surfaces of the upper electrode 24 that are covered by the side surfaces of the active layer 31 in the third direction Dz.

[0129] As shown in FIG. 22, the detection device 1D has an insulating film 38, a light-shielding layer 360, an insulating film 28 (organic insulating film), a photodiode PD, a light-shielding layer 37, and a sealing film 90 stacked in this order on a sensor substrate 210.

[0130] The light-shielding layer 37 is provided at a position where it overlaps the entire semiconductor layer 61 , the source electrode 62 , the drain electrode 63 and the gate electrode 64 .

[0131] The detection device 1D is configured as a top-light-receiving optical sensor. That is, light L1 emitted from light sources 53, 54 (see FIG. 11 ) and transmitted through or reflected by the detection object Fg passes through the sealing film 90 and is irradiated onto the upper electrode 24 side of the photodiode PD. The light L1 passes through the opening OP in the light-shielding layer 37 and is irradiated onto the active layer 31 of the photodiode PD. Carriers (holes and electrons) generated in the active layer 31 pass through the lower buffer layer 32 and upper buffer layer 33 to reach the lower electrode 23 and upper electrode 24, respectively.

[0132] In this embodiment, too, light L1 is blocked in the region overlapping with the light-shielding layer 37, and is not irradiated onto the portion of the active layer 31 that overlaps with the light-shielding layer 37. More specifically, light L1 is not irradiated onto the portions that overlap with the end of the lower buffer layer 32, the end of the active layer 31, the end of the upper buffer layer 33, and the end of the lower electrode 23. This suppresses the generation of carriers (holes and electrons) in the portion of the active layer 31 that overlaps with the light-shielding layer 37. As a result, the detection device 1 having an OPD can improve detection accuracy.

[0133] The components of each of the above-described embodiments can be combined as appropriate. Furthermore, other effects and advantages brought about by the aspects described in the present embodiments that are obvious from the description in this specification or that can be conceived by a person skilled in the art are naturally understood to be brought about by the present invention.

[0134] 1, 1A, 1B, 1C, 1D Detector 11 Lower electrode 12 Lower buffer layer 13 Active layer 14 Upper buffer layer 15, 15A, 15B Upper electrode 21 First substrate 23 Lower electrode 24 Upper electrode 31 Active layer 32 Lower buffer layer 33 Upper buffer layer 39, 39A, 36, 37 Light-shielding layer 62 Source electrode 63 Drain electrode 64 Gate electrode Fg Detected object PD Photodiode

Claims

1. A substrate; a plurality of photodiodes each having a lower electrode, a lower buffer layer, an active layer, an upper buffer layer, and an upper electrode stacked in this order on the substrate; a light-shielding layer provided in a region overlapping an end of the lower buffer layer, an end of the active layer, an end of the upper buffer layer, and an end of the lower electrode in a plan view; the upper electrode covers the lower buffer layer, the active layer, the upper buffer layer, and the lower electrode; the lower buffer layer, the active layer, the upper buffer layer, and the lower electrode are arranged separately for each of the plurality of photodiodes; Detection device.

2. the light-shielding layer is provided between the substrate and the lower electrode in a direction perpendicular to the substrate; The detection device according to claim 1 .

3. the light-shielding layer is provided to cover an end portion of the upper electrode; The detection device according to claim 1 .

4. a driving transistor disposed at a position overlapping the lower electrode; the driving transistor has a source electrode and a drain electrode; the light-shielding layer is a metal layer or an alloy layer provided in the same layer as the source electrode and the drain electrode; The detection device according to claim 1 .

5. the light-shielding layer is provided to cover the inclined surface of the upper electrode that covers the side surface of the active layer, The light-shielding layer is made of a metal material or an alloy material. The detection device according to claim 1 .

6. a light source for irradiating the object to be detected with light; the light emitted from the light source and transmitted through or reflected by the detection object is irradiated onto the lower electrode side of the photodiode; 5. The detection device according to claim 2 or 4.

7. a light source for irradiating the object to be detected with light; the light emitted from the light source and transmitted through or reflected by the detection object is irradiated onto the upper electrode side of the photodiode; the substrate; 6. The detection device according to claim 3 or 5.