Detection device

Abstract

Provided is a detection device that can improve detection accuracy. The detection device comprises: a substrate having a notch part between both ends in a first direction; a light source arranged in the notch part of the substrate; a terminal part provided at one of the ends in the first direction of the substrate; at least one first optical sensor provided on the substrate; and at least one second optical sensor provided on the substrate. In the first direction, the first optical sensor and the second optical sensor are arranged with the notch part of the substrate interposed therebetween. The first optical sensor and the second optical sensor each have a lower electrode, a lower buffer layer, and an active layer. The active layer of the first optical sensor and the active layer of the second optical sensor have thereon upper electrodes to which a reference potential is supplied from the terminal part. The lower electrode of the first optical sensor and the lower electrode of the second optical sensor are electrically connected to each other and are electrically connected to the terminal part.

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, sensors having multiple photodiodes with an organic semiconductor material used as an active layer are known. Light emitted from a light source is scattered and reflected by the object to be detected, and then incident on each of the multiple photodiodes. As a result, the multiple photodiodes detect biometric information of the object to be detected.

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

[0004] In such an optical sensor, when a plurality of photodiodes are arranged side by side, the total light receiving area of ​​the plurality of photodiodes is small, so the light receiving sensitivity of the optical sensor may be low.

[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 comprises a first substrate having a cutout between both ends in a first direction, a light source disposed in the cutout of the first substrate, a terminal portion provided at one end of the first substrate in the first direction, at least one first optical sensor provided on the first substrate, and at least one second optical sensor provided on the first substrate, wherein the first optical sensor and the second optical sensor are disposed on either side of the cutout of the first substrate in the first direction, and each of the first optical sensor and the second optical sensor has a lower electrode, a lower buffer layer, and an active layer, and the active layer of the first optical sensor and the active layer of the second optical sensor each have an upper electrode to which a reference potential is supplied from the terminal portion, and the lower electrode of the first optical sensor and the lower electrode of the second optical sensor are electrically connected and are also electrically connected to the terminal portion.

[0007] FIG. 1 is a schematic diagram showing an example of the appearance of a detection device according to embodiment 1 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 developed view showing an example of the optical sensors of the detection device shown in FIG. 1. FIG. 4 is a 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 schematic cross-sectional view showing an example of the stacked configuration of the optical sensors taken along the line VI-VI' in FIG. 4. FIG. 7 is a circuit diagram showing an example of the configuration of a detection circuit according to an embodiment. FIG. 8 is a diagram showing an example of the configuration of the first optical sensor and the second optical sensor according to a comparative example. FIG. 9 is a diagram showing an example of the configuration of the first optical sensor and the second optical sensor according to embodiment 2. FIG. 10 is a schematic cross-sectional view showing an example of the configuration of the detection device according to embodiment 2.

[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] (Embodiment 1) FIG. 1 is a schematic diagram showing an example of the appearance of a detection device according to embodiment 1 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 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 sensor taken along the line V-V' in FIG. 4. FIG. 6 is a schematic cross-sectional view showing an example of the stacked configuration of the optical sensor taken along the line VI-VI' in FIG. 4. FIG. 7 is a circuit diagram showing an example of the configuration of a detection circuit according to an embodiment. FIG. 8 is a configuration diagram showing an example of the configuration of the first optical sensor and the second optical sensor according to a comparative example.

[0011] The detection device 1 shown in FIG. 1 is a ring-shaped device that can be attached to and detached from the human body, and is worn on a finger Fg of the human body. The finger Fg includes the thumb, index finger, middle finger, ring finger, little finger, etc. The human body is an individual to be authenticated, whose identity is verified by the detection device 1. The detection device 1 can detect biometric information about a living body from the finger Fg on which it is worn. The finger Fg is an example of a measurement target. The measurement target is a living body or part of a living body, and is a 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, at least one first optical sensor 10A, at least one second optical sensor 10B, and a flexible printed circuit board 70. The detection device 1 includes a battery (not shown) inside the housing 200 and is a device that operates on battery power.

[0013] The housing 200 is formed in a ring shape (annular shape) that can be worn on a finger Fg and is a wearable member that is worn on a living body. In the example shown in FIG. 2 , the housing 200 includes a first housing 210 and a second housing 220. The first housing 210 and the second housing 220 are integrally formed into a ring shape. The first housing 210 is a member that comes into contact with the human body on which the housing 200 is worn. The first housing 210 houses the light source 60, the first optical sensor 10A, the second optical sensor 10B, etc. The first housing 210 is formed in a ring shape using a housing material such as a transparent synthetic resin or silicone. The second housing 220 has a surface of the housing 200 that covers the outer peripheral surface 210A of the first housing 210. The second housing 220 is formed in a ring shape using a material such as a metal or a non-transparent synthetic resin. The housing 200 accommodates the 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 first housing 210. The flexible printed circuit board 70 is accommodated inside the housing 200, for example, by forming the housing 200 in a ring shape using a mold and filling the surrounding area with a filling material.

[0014] As shown in FIG. 3 , the flexible printed circuit board 70 is formed in a deformable band shape, and is formed into a ring shape by connecting one end 71 and the other end 72. 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 across the vicinity of the light source 60 in the first mounting area 73. The first substrate 21 is a sensor substrate on which the first optical sensor 10A, the second optical sensor 10B, and the like are mounted. 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] 3 and 4 , the detection device 1 further includes a first substrate 21, a second substrate 50, and a terminal portion 40. The first substrate 21 is an insulating substrate and is formed in a strip shape from, for example, a film-like synthetic resin. The first substrate 21 is formed as a single substrate having one end 21A and the other end 21B. The first substrate 21 is deformable, with the first optical sensor 10A mounted on the one end 21A side and the second optical sensor 10B mounted on the other end 21B side.

[0017] 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 cutout portion 22 between the first optical sensor 10A and the second optical sensor 10B in the circumferential direction 200C of the housing 200. The cutout portion 22 will be described later.

[0018] As shown in FIG. 4 , the terminal unit 40 is a device for electrically connecting the area of ​​the first optical sensor 10A and the second optical sensor 10B on the first substrate 21 to the control circuit 122 and the power supply circuit 123 on the flexible printed circuit board 70. The terminal unit 40 is mounted on the first substrate 21 and electrically connected to the first wiring 26A, the second wiring 26B, the third wiring 26C, etc. on the first substrate 21. The first wiring 26A, the second wiring 26B, and the third wiring 26C are metal wires on the same layer of the first substrate 21. The terminal unit 40 supplies a power signal (power) from the power supply circuit 123 to the first optical sensor 10A via the first wiring 26A. The terminal unit 40 supplies a power signal (power) from the power supply circuit 123 to the second optical sensor 10B via the second wiring 26B. The terminal unit 40 has a plurality of terminals and is configured to be electrically connectable to a plurality of wirings.

[0019] The terminal portion 40 is provided on one end portion 21A of the first substrate 21. The terminal portion 40 supplies power from the power supply circuit 123 to the first optical sensor 10A and the second optical sensor 10B.

[0020] The second substrate 50 is an insulating substrate, similar to the first substrate 21, and is formed in a strip shape from, for example, a film-like synthetic resin, etc. The second substrate 50 covers a sealing film 90 (see FIGS. 5 and 6 ), and is a deformable substrate.

[0021] 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.

[0022] As shown in FIG. 2 , the light source 60 is provided inside the first housing 210 of the housing 200 and is configured to be able to irradiate light toward the finger Fg wearing the housing 200. The light source 60 is disposed in the cutout portion 22 of the first substrate 21. For example, an inorganic light emitting diode (LED) or an organic light emitting diode (OLED) 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, green light, etc.

[0023] Light emitted from the light source 60 is reflected by the surface of the object to be detected, such as a finger 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 projections and recesses on the surface of the finger Fg. Alternatively, the light emitted from the light source 60 may be reflected inside the finger Fg or pass through the finger Fg before entering 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 the finger Fg. Examples of information about a living body include pulse waves, pulse rates, and blood vessel images of the finger or palm. That is, the detection device 1 may be configured as a fingerprint detection device that detects fingerprints, or a vein detection device that detects vascular patterns such as veins.

[0024] Each of the first optical sensor 10A and the second optical sensor 10B detects light emitted by the light source 60 and reflected by a finger Fg or the like, 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 on the housing 200 so as to be adjacent to one end 61 of the light source 60 in the circumferential direction 200C of the housing 200. The second optical sensor 10B is provided on the housing 200 so as to be adjacent to the other end 62 of the light source 60 in the circumferential direction 200C of the housing 200.

[0025] As shown in Fig. 4, the first optical sensor 10A and the second optical sensor 10B each have a plurality of photodiodes PD (see Fig. 4), which are organic photodiodes. The first optical sensor 10A has three lower electrodes 11A, 11B, and 11C aligned along the circumferential direction 200C. The second optical sensor 10B has three lower electrodes 11D, 11E, and 11F 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.

[0026] 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. Note that 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.

[0027] As shown in FIG. 4 , the first optical sensor 10A is configured such that three lower electrodes 11A, 11B, and 11C aligned in the first direction Dx are covered by one upper electrode 15A. The second optical sensor 10B is configured such that three lower electrodes 11D, 11E, and 11F aligned in the first direction Dx are covered by one upper electrode 15B. 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. In a plan view, the upper electrode 15A covers the three lower electrodes 11A, 11B, and 11C. In a plan view, the upper electrode 15B covers the three lower electrodes 11D, 11E, and 11F. The upper electrodes 15A and 15B have rectangular surfaces and are independent electrodes that are not electrically connected.

[0028] The first substrate 21 has a first power supply electrode 25A and a second power supply electrode 25B extending along the second direction Dy. The first power supply electrode 25A is provided between one end 21A of the first substrate 21 and the first optical sensor 10A in the first direction Dx. The second power supply electrode 25B is provided between the other end 21B of the first substrate 21 and the second optical sensor 10B in the first direction Dx. The first power supply electrode 25A is electrically connected to a terminal 40 of the first substrate 21 via a first wiring 26A, and a power signal is supplied from the power supply circuit 123 (see FIG. 3 ) via the terminal 40. The second power supply electrode 25B is electrically connected to the terminal 40 of the first substrate 21 via a second wiring 26B, and a power signal is supplied from the power supply circuit 123 via the terminal 40.

[0029] Each of the lower electrodes 11A, 11B, and 11C of the first optical sensor 10A is connected to the terminal portion 40 via the third wiring 26C. Each of the lower electrodes 11F of the second optical sensor 10B is connected to the terminal portion 40 via the third wiring 26C. The multiple third wirings 26C of the first substrate 21 are connected to a detection circuit 48 included in the control circuit 122 via the terminal portion 40 and signal lines SL of the flexible printed circuit board 70. In other words, the detection circuit 48 is electrically connected to the lower electrodes 11A, 11B, and 11C of the first optical sensor 10A and the lower electrode 11F of the second optical sensor 10B via the signal lines SL. The detection circuit 48 and the power supply circuit 123 included in the control circuit 122 may each be formed as separate circuits.

[0030] The third wiring 26C is formed of, for example, a metal wiring, and is formed of a material having better conductivity than the lower electrode 11 of the photodiode PD. The third wiring 26C is formed of, for example, a light-transmitting conductive material such as ITO (Indium Tin Oxide). Note that the third wiring 26C may be formed in the same layer as the lower electrode 11, or may be formed of metal.

[0031] The upper electrode 15A of the first optical sensor 10A is connected to the first power supply electrode 25A via the conductive material 24 and is electrically connected to the terminal 40 via the first wiring 26A connected to the first power supply electrode 25A. The upper electrode 15B of the second optical sensor 10B is connected to the second power supply electrode 25B via the conductive material 24 and is electrically connected to the terminal 40 via the second wiring 26B connected to the second power supply electrode 25B. As a result, the upper electrode 15A and the upper electrode 15B are each supplied with power from the independent power systems of the first power supply electrode 25A and the second power supply electrode 25B. The conductive material 24 is made of a conductive material and covers the entire surface of the first power supply electrode 25A or the second power supply electrode 25B, electrically connecting the first power supply electrode 25A to the upper electrode 15A and the second power supply electrode 25B to the upper electrode 15B. The upper electrode 15A may be directly connected to the first and second power supply electrodes 25A and 25B without the conductive material 24 therebetween.

[0032] 4, the first substrate 21 has one end 21A of the first optical sensor 10A and the other end 21B of the second optical sensor 10B, and is formed integrally as a single common substrate. A notch 22 is formed in the first substrate 21 between the one end 21A of the first optical sensor 10A and the other end 21B of the second optical sensor 10B in the first direction Dx. The first substrate 21 has the notch 22 between the first optical sensor 10A and the second optical sensor 10B, and a connecting portion 23 that contacts the notch 22 and is located between the first optical sensor 10A and the second optical sensor 10B.

[0033] The cutout portion 22 is formed over a distance in the first direction Dx that is longer than the length of the light source 60. The cutout portion 22 is formed over a distance in the second direction Dy that is longer than the length of the light source 60 but shorter than the length (width) of the first substrate 21. The first substrate 21 is integrally formed by connecting the regions of the first optical sensor 10A and the second optical sensor 10B via a connecting portion 23 of the cutout portion 22. The cutout portion 22 is formed in a shape that allows the light source 60 to be disposed therein. In this embodiment, the cutout portion 22 is formed in a substantially rectangular shape in a plan view, but may be shaped, for example, semicircular, triangular, polygonal, or the like. The connecting portion 23 is provided with a second wiring 26B and a third wiring 26C.

[0034] 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 to the detection circuit 48. In this embodiment, the detection signals from 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 based on the detection signals from the multiple photodiodes PD.

[0035] The first power supply electrode 25A and the second power supply electrode 25B receive a power supply signal from the power supply circuit 123 via the terminal portion 40, and supply the power supply signal to the upper electrode 15A and the upper electrode 15B. In the example shown in Fig. 4, the first power supply electrode 25A and the second power supply electrode 25B are formed in a substantially rectangular shape extending in the second direction Dy in a plan view, and have the same area (size).

[0036] The power supply circuit 123 supplies a first reference potential Vref (see FIG. 7) to the lower electrode 11 of the photodiode PD via the terminal unit 40, and supplies a second reference potential Vorg (see FIG. 7) to the upper electrode 15 of the photodiode PD. The first reference potential Vref is a fixed, predetermined potential. The second reference potential Vorg is a fixed, predetermined potential.

[0037] The first reference potential Vref is higher than the second reference potential Vorg, so that the photodiode PD is reverse-biased.

[0038] The plurality of photodiodes PD each output an electrical signal (photocurrent Id) corresponding to the light irradiating thereon to the detection circuit 48. As a result, the detection device 1 detects information about the object to be detected based on the photocurrent Id from the plurality of photodiodes PD.

[0039] The lower electrode 11 of the first optical sensor 10A and the lower electrode 11 of the second optical sensor 10B are electrically connected to each other and are also electrically connected to the terminal portion 40. In this embodiment, the lower electrodes 11B and 11E are electrically connected to each other via the fourth wiring 26D and are also electrically connected to the terminal portion 40. The lower electrodes 11C and 11F are electrically connected to each other via the fourth wiring 26E and are also electrically connected to the terminal portion 40.

[0040] The fourth wirings 26D and 26E, like the third wiring 26C, are formed of, for example, metal wiring, and are formed of a material having better conductivity than the lower electrode 11 of the photodiode PD.

[0041] The first optical sensor 10A has a plurality of first optical sensors 10A1, 10A2, and 10A3, and the second optical sensor 10B has a plurality of first optical sensors 10B1, 10B2, and 10B3. Among the first optical sensors 10A1, 10A2, and 10A3 and the plurality of second optical sensors 10B1, 10B2, and 10B3, a combination of a first optical sensor 10A and a second optical sensor 10B that are in the same order counting from the cutout portion 22 is defined as a first optical sensor 10A and a second optical sensor 10B. In at least one combination of a first optical sensor 10A and a second optical sensor 10B, the respective lower electrodes 11 are electrically connected to each other.

[0042] In this embodiment, the combinations of the first optical sensor 10A and the second optical sensor 10B are the first optical sensor 10A1 and the first optical sensor 10B1, the first optical sensor 10A2 and the first optical sensor 10B2, and the first optical sensor 10A3 and the first optical sensor 10B3. In the combination of the first optical sensor 10A2 and the first optical sensor 10B2, the second lower electrodes 11B and 11E, counting from the cutout portion 22, are electrically connected. In the combination of the first optical sensor 10A3 and the first optical sensor 10B3, the first lower electrodes 11C and 11D, counting from the cutout portion 22, are electrically connected.

[0043] This makes it possible to suppress variations in the characteristics of the pulse wave signal due to differences in the distance from the light source 60 to the lower electrode 11 .

[0044] In other combinations of the first optical sensor 10A and the second optical sensor 10B, the respective lower electrodes 11 are not electrically connected to each other. In this embodiment, the lower electrodes 11A and 11F are not electrically connected to each other.

[0045] Furthermore, in the combination of the first optical sensor 10A and the second optical sensor 10B arranged closest to the cutout 22, the respective lower electrodes 11 are electrically connected to each other, whereas in the combination of the first optical sensor 10A and the second optical sensor 10B arranged farthest from the cutout 22, the respective lower electrodes 11 are not electrically connected to each other. In this embodiment, in the combination of the first optical sensor 10A3 and the second optical sensor 10B3 arranged closest to the cutout 22, the lower electrodes 11C and 11D are electrically connected, whereas in the combination of the first optical sensor 10A1 and the second optical sensor 10B1 arranged farthest from the cutout 22, the lower electrodes 11A and 11F are not electrically connected.

[0046] This makes it possible to prevent lower electrodes 11A and 11F, which are located at positions farthest from light source 60, from receiving different pulse wave signals.

[0047] Furthermore, in at least one combination of the first optical sensor 10A and the second optical sensor 10B, the areas of the respective lower electrodes 11 are equal. In this embodiment, in the combinations of the lower electrodes 11A and 11F, the lower electrodes 11B and 11E, and the lower electrodes 11C and 11D, the areas of the respective lower electrodes 11 are equal.

[0048] 5 , the first optical sensor 10A has a first substrate 21 (one end 21A), a photodiode PD, and a second substrate 50 facing the first substrate 21. In this embodiment, the first optical sensor 10A further has a first insulating layer 27, an insulating film 28, a sealing film 90, and a second insulating layer 270.

[0049] 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 insulating film 28. 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.

[0050] The insulating film 28 is provided on the first insulating layer 27. The insulating film 28 is disposed between the first insulating layer 27 and the photodiode PD. Like the first insulating layer 27 and the second insulating layer 270, the insulating film 28 may be an inorganic insulating film or an organic insulating film.

[0051] The photodiode PD is provided on the first insulating layer 27 as a sensor element. The photodiode PD has 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 photodiode PD is 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), and the upper electrode 15 in this order in a third direction Dz perpendicular to the first substrate 21. If the upper electrode 15 is not provided, the upper buffer layer 14 serves as the cathode electrode of the photodiode PD.

[0052] The lower electrode 11 is an anode electrode of the photodiode PD and is formed of a light-transmitting conductive material such as indium tin oxide (ITO). The characteristics (e.g., voltage-current characteristics and resistance value) of the active layer 13 change depending on the light irradiated thereon. 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 fullerene derivative (PCBM), which is an n-type organic semiconductor, are mixed. The active layer 13 may be made of, for example, a low molecular weight organic material such as C60 (fullerene), PCBM (phenyl C61-butyric acid methyl ester), CuPc (copper phthalocyanine), F16CuPc (fluorinated copper phthalocyanine), rubrene (5,6,11,12-tetraphenyltetracene), or PDI (a perylene derivative).

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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 over the entire first optical sensor 10A and the second optical sensor 10B. In other words, the upper electrode 15 is continuously provided over the multiple photodiodes PD. The upper electrode 15 faces the multiple lower electrodes 11 (11A, 11B, 11C) across the lower buffer layer 12, the active layer 13, and the upper buffer layer 14. The upper electrode 15 is formed of a light-transmitting conductive material such as ITO or IZO. A portion of the end of the upper surface 150 of the upper electrode 15 is electrically connected to a conductive material 24. The conductive material 24 is electrically connected to a first power supply electrode 25A and supplies a power signal from the first power supply electrode 25A to the upper electrode 15. In the first optical sensor 10A, the photodiode PD is well sealed by providing the sealing film 90 on the upper electrode 15, the conductive material 24, etc. The upper electrode 15 may be a laminated film made of a plurality of light-transmitting conductive materials.

[0058] The sealing film 90 is provided on the upper electrode 15. 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.

[0059] 6 , the second optical sensor 10B has three lower electrodes 11 (11D, 11E, 11F) in a region of the first substrate 21 different from the region of the lower electrodes 11 (11A, 11B, 11C) of the first optical sensor 10A. The lower electrodes 11D, 11E, 11F are covered with a lower buffer layer 12, an active layer 13, an upper buffer layer 14, and an upper electrode 15 (15B). In this embodiment, the second optical sensor 10B has a first substrate 21 (the other end 21B), a photodiode PD, a first insulating layer 27, an insulating film 28, a second substrate 50 facing the first substrate 21, and a second insulating layer 270. The photodiode PD, the first insulating layer 27, the insulating film 28, and the second insulating layer 270 have the same configurations as the photodiode PD, the first insulating layer 27, the insulating film 28, and the second insulating layer 270 of the first optical sensor 10A described above. That is, the photodiode PD of the second optical sensor 10B has a lower electrode 11 (11D, 11E, 11F), 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.

[0060] In the second optical sensor 10B, a portion of an end of an upper surface 150 of the upper electrode 15 (15B) is electrically connected to the conductive material 24, and the conductive material 24 is electrically connected to the second power supply electrode 25B. In the second optical sensor 10B, a power supply signal is supplied from the second power supply electrode 25B to the upper electrode 15. In the second optical sensor 10B, a sealing film 90 is provided on the upper electrode 15 (15B), the conductive material 24, etc., so that the photodiode PD is well sealed.

[0061] 7 is a circuit diagram showing an example of the configuration of a detection circuit according to an embodiment. As shown in FIG. 7, a plurality of photodiodes PD1, PD2, PD3, and PD4 are connected to a detection circuit 48 via connection switches SSW1, SSW2, SSW3, and SSW4.

[0062] In the following description, when it is not necessary to distinguish between the photodiodes PD1, PD2, PD3, and PD4, they will simply be referred to as photodiodes PD. Furthermore, when it is not necessary to distinguish between the connection switches SSW1, SSW2, SSW3, and SSW4, they will simply be referred to as connection switches SSW.

[0063] Here, photodiode PD1 is a photodiode having a lower electrode 11A. Photodiode PD2 is a photodiode having lower electrodes 11B and 11E. Photodiode PD3 is a photodiode having lower electrodes 11C and 11D. Photodiode PD4 is a photodiode having a lower electrode 11F.

[0064] The control circuit 122 includes a detection circuit 48 and a memory circuit 49. The detection circuit 48 includes a detection signal amplifier circuit 45 and an ADC (Analog Digital Converter) circuit 47.

[0065] The detection circuit 48 is a current detection circuit that measures the photocurrent Id output from the photodiode PD. The detection circuit 48 is a signal processing circuit that has at least the functions of the detection signal amplifier circuit 45 and the ADC circuit 47.

[0066] The memory circuit 49 temporarily stores information about the photocurrent Id measured by the detection circuit 48. The memory circuit 49 may be, for example, a RAM (Random Access Memory), a register circuit, or the like.

[0067] The anode of each photodiode PD is supplied with the second reference potential Vorg from the power supply circuit 52. That is, the second reference potential Vorg is supplied to each of the upper electrodes 15 of the first optical sensor 10A and the second optical sensor 10B. The cathode of the photodiode PD is connected to the detection circuit 48 via the connection switch SSW.

[0068] The sensor capacitance Cd is connected in parallel to the photodiode PD and is formed between the upper electrode 15 and the lower electrode 11 of the photodiode PD.

[0069] The inverting input (−) of the detection signal amplifier circuit 45 is connected to the photodiode PD via a connection switch SSW. The multiple photodiodes PD1, PD2, PD3, and PD4 are connected in parallel to the inverting input (−) of the detection signal amplifier circuit 45 via multiple connection switches SSW1, SSW2, SSW3, and SSW4, respectively.

[0070] The first reference potential Vref is supplied to the non-inverting input (+) of the detection signal amplifier circuit 45 from the power supply circuit 123. The output of the detection signal amplifier circuit 45 is connected to the ADC circuit 47.

[0071] The detection signal amplifier circuit 45 amplifies the detection signal of each photodiode. The ADC circuit 47 converts the analog signal output from the detection signal amplifier circuit 45 into a digital signal. The detection circuit 48 measures the photocurrent Id output from the photodiode PD, performs signal processing such as A / D conversion, and stores in a memory circuit 49 a sensor value Raw, which is a detection value of each photodiode PD corresponding to the photocurrent Id.

[0072] The detection circuit 48 acquires a sensor value Raw(n) (n is an integer from 1 to N, N is the total number of frames) for each photodiode PD. The control circuit 122 outputs an output value Data(n) (n is an integer from 1 to N, N is the total number of frames) for each photodiode PD to an external host (not shown).

[0073] 8 is a configuration diagram showing an example of the configuration of the first optical sensor and the second optical sensor according to the comparative example. As shown in Fig. 8, in the detection device 1A according to the comparative example, the plurality of lower electrodes 11 arranged at equal intervals on both sides of the cutout portion 22 in the first direction Dx are not electrically connected to each other, as compared with the detection device 1 according to the embodiment.

[0074] This may reduce the total light receiving area of ​​the optical sensor, resulting in a decrease in the light receiving sensitivity of the optical sensor.

[0075] In contrast, in the detection device 1 according to the first embodiment, the plurality of lower electrodes 11 arranged at equal intervals on both sides of the cutout portion 22 in the first direction Dx are electrically connected to each other, which increases the light receiving area of ​​the photodiode PD and improves the light receiving sensitivity of the optical sensor.

[0076] Furthermore, in the detection device 1A of the comparative example, compared to the detection device 1 of the embodiment, the area of ​​the lower electrode 11 of the first optical sensor 10A and the area of ​​the lower electrode 11 of the second optical sensor 10B are equal and of uniform size.

[0077] Therefore, as the distance from the light source 60 to the lower electrode 11 increases, the amount of light reaching the optical sensor decreases exponentially, which may result in a decrease in the light receiving sensitivity of the optical sensor.

[0078] In contrast, in the detection device 1 according to the first embodiment, in at least one combination of the first optical sensor 10A and the second optical sensor 10B, the area of ​​the lower electrode 11 of the first optical sensor 10A or the area of ​​the lower electrode 11 of the second optical sensor 10B is different from the area of ​​the lower electrode 11 of another combination of the first optical sensor 10A and the second optical sensor 10B. In this embodiment, the area of ​​each of the lower electrodes 11A and 11F in the combination of the first optical sensor 10A1 and the second optical sensor 10B1 is different from the area of ​​each of the lower electrodes 11B and 11E in the combination of the first optical sensor 10A3 and the second optical sensor 10B3. Furthermore, the area of ​​each of the lower electrodes 11A and 11F in the combination of the first optical sensor 10A1 and the second optical sensor 10B1 is different from the area of ​​each of the lower electrodes 11C and 11D in the combination of the first optical sensor 10A2 and the second optical sensor 10B2.

[0079] Furthermore, the area of ​​the lower electrode 11 of the combination of the first optical sensor 10A and the second optical sensor 10B arranged at a position farthest from the cutout portion 22 is larger than the area of ​​the lower electrode 11 of the combination of the first optical sensor 10A and the second optical sensor 10B arranged at a position nearest to the cutout portion 22. In other words, the area of ​​the lower electrodes 11A, 11F of the combination of the first optical sensor 10A1 and the second optical sensor 10B1 arranged at a position farthest from the cutout portion 22 is larger than the area of ​​the lower electrodes 11C, 11D of the combination of the first optical sensor 10A3 and the second optical sensor 10B3 arranged at a position nearest to the cutout portion 22.

[0080] This makes it possible to increase the light receiving sensitivity and to prevent the amount of light reaching the optical sensor from exponentially decreasing as the distance from the light source 60 to the lower electrode 11 increases.

[0081] 9 is a configuration diagram showing an example of the configuration of a first optical sensor and a second optical sensor according to embodiment 2. In the following description, the same components as those described in the above embodiment are denoted by the same reference numerals, and redundant description will be omitted.

[0082] In the detection device 1B according to the second embodiment, the first optical sensor 10A and the second optical sensor 10B further include a light-shielding layer LS1, which is larger than the lower electrodes 11. At least one lower electrode 11 is covered with the light-shielding layer LS1 in a plan view and is electrically connected to the terminal portion 40.

[0083] 9, the light-shielding layer LS1 is provided at a position overlapping the lower electrode 11B in the third direction Dz. The light-shielding layer LS1 is made of a non-light-transmitting material.

[0084] In this embodiment, the light-shielding layer LS1 is larger than the lower electrodes 11B and 11E, and each of the lower electrodes 11B and 11E is covered with the light-shielding layer LS1 in a planar view, and the lower electrode 11B is electrically connected to the terminal portion 40.

[0085] In addition, in at least one combination of the first optical sensor 10A and the second optical sensor 10B, the lower electrodes 11 covered with the light-shielding layer LS1 are electrically connected to each other. In this embodiment, in the combination of the first optical sensor 10A2 and the second optical sensor 10B2, the lower electrodes 11B and 11E covered with the light-shielding layer LS1 are electrically connected to each other.

[0086] At this time, the output value Data(n) of the photodiode PD1 is a difference value obtained by subtracting the sensor value Raw(n) of the photodiode PD2 from the sensor value Raw(n) of the photodiode PD1.

[0087] Similarly to the output value Data(n) of the photodiode PD1, the output value Data(n) of the photodiode PD3 is a difference value obtained by subtracting the sensor value Raw(n) of the photodiode PD2 from the sensor value Raw(n) of the photodiode PD3.

[0088] The output value Data(n) of the photodiode PD4, like the output value Data(n) of the photodiode PD1, is a difference value obtained by subtracting the sensor value Raw(n) of the photodiode PD2 from the sensor value Raw(n) of the photodiode PD4.

[0089] As a result, by using the photodiode PD2 shielded by the light-shielding layer LS1 as a reference element, it is possible to cancel noise from the optical sensor 10 and suppress the generation of electromagnetic noise.

[0090] The area of ​​each of the lower electrodes 11 covered with the light-shielding layer LS1 is equivalent to the area of ​​the lower electrodes 11 of the first optical sensor 10A or the second optical sensor 10B that are not covered with the light-shielding layer LS1 and whose lower electrodes 11 are electrically connected to each other. In this embodiment, the area of ​​each of the lower electrodes 11B, 11E covered with the light-shielding layer LS1 is equivalent to the area of ​​the lower electrode 11C or lower electrode 11D of the first optical sensor 10A3 or the second optical sensor 10B3 that are not covered with the light-shielding layer LS1 and whose lower electrodes 11 are electrically connected to each other.

[0091] As a result, the light receiving area of ​​the unshaded photodiode PD3 becomes equal to the light receiving area of ​​the shaded photodiode PD2, so the amount of noise in the photodiode PD3 can be cancelled, making gain adjustment unnecessary.

[0092] Furthermore, the total area of ​​the lower electrodes 11 covered with the light-shielding layer LS1 is equivalent to the area of ​​the lower electrodes 11 of the first optical sensor 10A or the second optical sensor 10B whose lower electrodes 11 are not electrically connected to each other. In this embodiment, the total area of ​​the lower electrodes 11B and 11E covered with the light-shielding layer LS1 is equivalent to the area of ​​the lower electrode 11A or the lower electrode 11F of the first optical sensor 10A1 or the second optical sensor 10B1 whose lower electrodes 11 are not electrically connected to each other.

[0093] As a result, the light receiving area of ​​each of the unshaded photodiodes PD1 and PD4 becomes equal to the light receiving area of ​​the shaded photodiode PD2, so the amount of noise in each of the photodiodes PD1 and PD4 can be cancelled out, making gain adjustment unnecessary.

[0094] Furthermore, in combinations of the first optical sensor 10A and the second optical sensor 10B other than the combination of the first optical sensor 10A and the second optical sensor 10B arranged closest to the cutout portion 22, the respective lower electrodes 11 are covered with the light-shielding layer LS1 in a planar view. In combinations of the first optical sensor 10A2 and the second optical sensor 10B2 in this embodiment, in combinations of the first optical sensor 10A2 and the second optical sensor 10B2 other than the combination of the first optical sensor 10A3 and the second optical sensor 10B3 arranged closest to the cutout portion 22, each of the lower electrodes 11B, 11E is covered with the light-shielding layer LS1 in a planar view.

[0095] As a result, the photodiode PD closest to the light source 60 can be effectively used for light sensing because it receives a large amount of green light or the like.

[0096] Furthermore, in combinations of the first optical sensor 10A and the second optical sensor 10B other than the combination of the first optical sensor 10A and the second optical sensor 10B arranged at a position farthest from the cutout portion 22, the respective lower electrodes 11 are covered with the light-shielding layer LS1 in a planar view. In the present embodiment, in combinations of the first optical sensor 10A2 and the second optical sensor 10B2 other than the combination of the first optical sensor 10A1 and the second optical sensor 10B1 arranged at a position farthest from the cutout portion 22, the respective lower electrodes 11B, 11E are covered with the light-shielding layer LS1 in a planar view.

[0097] This allows the photodiode PD, which is farthest from the light source 60, to improve the quality of the detection signals of near-infrared light, red light, and the like.

[0098] Fig. 10 is a cross-sectional view showing a configuration example of a detection device according to embodiment 2. Fig. 10 is a cross-sectional view showing a configuration example of an optical sensor taken along the X-X' cross section shown in Fig. 3. As shown in Fig. 10, when the detection device 1B is worn on a finger Fg and the light source 60 emits light L, the light L passes through the housing 200 and is irradiated onto the finger Fg. The light L includes green light L1 and near-infrared light L2. Note that the near-infrared light L2 may be red light.

[0099] Light L enters the inside of the finger Fg through the skin and is transmitted through or reflected by muscle tissue, arteries, veins, etc. Reflected light L11, L21, which are green light L1 and near-infrared light L2 reflected inside the finger Fg, travels toward the detection device 1. When the reflected light L11, L21 is emitted toward the outside of the finger Fg and reaches the optical sensor 10 of the detection device 1, the reflected light L11, L21 is received by each photodiode PD of the detection device 1B.

[0100] The lower electrode 11B between the lower electrode 11A arranged closest to the light source 60 and the lower electrode 11C arranged closest to the light source 60 is shielded from the reflected light L11 and L21 by the light-shielding layer LS1.

[0101] The lower electrode 11C is used as a light sensing element for green light L1, and the lower electrode 11A is used as a light sensing element for near-infrared light L2.

[0102] As a result, the distance between the light-shielded lower electrode 11B and both the lower electrode 11A and the lower electrode 11C is short, which improves the light detection accuracy of each of the photodiodes PD3 and PD4. Note that although an example configuration on the first optical sensor side is described in Fig. 10, the light detection accuracy of each of the photodiodes PD1 and PD3 on the second optical sensor side can also be improved in a similar manner.

[0103] Furthermore, other effects and advantages brought about by the aspects described in this embodiment that are clear from the description in this specification or that can be appropriately thought of by a person skilled in the art are naturally understood to be brought about by the present invention.

[0104] REFERENCE SIGNS LIST 1, 1A, 1B Detecting device 10A First optical sensor 10B Second optical sensor 11 Lower electrode 12 Lower buffer layer 13 Active layer 15, 15A, 15B Upper electrode 21 First substrate 22 Notch portion 40 Terminal portion 60 Light source LS1 Light-shielding layer PD Photodiode

Claims

1. A detection device comprising: a first substrate having a cutout between both ends in a first direction; a light source arranged in the cutout of the first substrate; a terminal portion provided at one end of the first substrate in the first direction; at least one first optical sensor provided on the first substrate; and at least one second optical sensor provided on the first substrate, wherein in the first direction, the first optical sensor and the second optical sensor are arranged to sandwich the cutout of the first substrate, each of the first optical sensor and the second optical sensor has a lower electrode, a lower buffer layer, and an active layer, and an upper electrode to which a reference potential is supplied from the terminal portion is provided on the active layer of the first optical sensor and the active layer of the second optical sensor, respectively, and the lower electrode of the first optical sensor and the lower electrode of the second optical sensor are electrically connected and are also electrically connected to the terminal portion.

2. The detection device according to claim 1, comprising a plurality of the first optical sensors and a plurality of the second optical sensors, wherein among the plurality of the first optical sensors and the plurality of the second optical sensors, there are combinations of first optical sensors and second optical sensors that are in the same order counting from the cutout portion, and in at least one combination of the first optical sensors and second optical sensors, the respective lower electrodes are electrically connected to each other.

3. The detection device according to claim 2, wherein in other combinations of the first optical sensor and the second optical sensor, the respective lower electrodes are not electrically connected to each other.

4. The detection device described in claim 2, wherein in a combination of a first optical sensor and a second optical sensor arranged in a position closest to the cutout portion, the respective lower electrodes are electrically connected to each other, and in a combination of a first optical sensor and a second optical sensor arranged in a position farthest from the cutout portion, the respective lower electrodes are not electrically connected to each other.

5. The detection device according to claim 2, further comprising a light-shielding layer, the light-shielding layer being larger than the lower electrodes, and at least one of the lower electrodes being covered by the light-shielding layer in a planar view and electrically connected to the terminal portion.

6. The detection device according to claim 5, wherein in at least one combination of the first optical sensor and the second optical sensor, the lower electrodes covered with the light-shielding layer are electrically connected to each other.

7. The detection device according to claim 6, wherein the area of ​​each of the lower electrodes covered with the light-shielding layer is equal to the area of ​​the lower electrodes of the first optical sensor or the second optical sensor which are not covered with the light-shielding layer and whose lower electrodes are electrically connected to each other.

8. The detection device according to claim 6, wherein the total area of ​​the lower electrodes covered with the light-shielding layer is equal to the area of ​​the lower electrodes of the first optical sensor or the second optical sensor whose lower electrodes are not electrically connected to each other.

9. The detection device according to claim 5, wherein in combinations of the first and second optical sensors other than the combination of the first and second optical sensors arranged in a position closest to the cutout portion, the respective lower electrodes are covered by the light-shielding layer in a planar view.

10. The detection device described in claim 5, wherein in combinations of the first and second optical sensors other than the combination of the first and second optical sensors arranged at a position farthest from the cutout portion, the respective lower electrodes are covered by the light-shielding layer in a planar view.

11. The detection device according to claim 2, wherein the areas of the lower electrodes of the at least one combination of the first optical sensor and the second optical sensor are equal to each other.

12. The detection device according to claim 11, wherein in at least one combination of the first optical sensor and the second optical sensor, the area of ​​the lower electrode of the first optical sensor or the area of ​​the lower electrode of the second optical sensor is different from the area of ​​the lower electrode of another combination of the first optical sensor and the second optical sensor.

13. The detection device described in claim 2, wherein the area of ​​the lower electrode of the combination of the first optical sensor and the second optical sensor arranged at a position farthest from the cutout portion is larger than the area of ​​the lower electrode of the combination of the first optical sensor and the second optical sensor arranged at a position closest to the cutout portion.

14. The detection device according to any one of claims 1 to 13, wherein the first and second optical sensors are organic photodiodes.

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