What is disclosed herein relates to a detection device.
Optical sensors capable of detecting fingerprint patterns and vascular patterns are known (for example, Japanese Patent Application Laid-open Publication No. 2009-032005). Flexible sheet sensors that use an organic semiconductor material as an active layer are known as such optical sensors.
In the optical sensors, electrode peeling may occur due to low adhesion between the active layer made of an organic material and a metal electrode stacked on the active layer.
For the foregoing reasons, there is a need for a detection device capable of restraining the occurrence of the electrode peeling.
According to an aspect of the present disclosure, a detection device includes a plurality of optical sensors arranged on a substrate. In each of the optical sensors: a lower electrode, an electron transport layer, an active layer, a hole transport layer, and an upper electrode are stacked in a direction orthogonal to a surface of the substrate in the order as listed; the active layer includes an organic semiconductor; and the hole transport layer includes a metal oxide layer and is provided on the active layer so as to be in contact with the active layer.
The following describes modes (embodiments) for carrying out the present disclosure in detail with reference to the drawings. The present disclosure is not limited to the description of the embodiments given below. Components described below include those easily conceivable by those skilled in the art or those substantially identical thereto. In addition, the components described below can be combined as appropriate. What is disclosed herein is merely an example, and the present disclosure naturally encompasses appropriate modifications easily conceivable by those skilled in the art while maintaining the gist of the disclosure. To further clarify the description, the drawings may schematically illustrate, for example, widths, thicknesses, and shapes of various parts as compared with actual aspects thereof. However, they are merely examples, and interpretation of the present disclosure is not limited thereto. The same component as that described with reference to an already mentioned drawing is denoted by the same reference numeral through the present specification and the drawings, and detailed description thereof may not be repeated where appropriate.
In the present specification and claims, in expressing an aspect of disposing another structure on or above a certain structure, a case of simply expressing “on” includes both a case of disposing the other structure immediately on the certain structure so as to contact the certain structure and a case of disposing the other structure above the certain structure with still another structure interposed therebetween, unless otherwise specified.
The sensor base member 21 is electrically coupled to a control substrate 121 through a flexible printed circuit board 71. The flexible printed circuit board 71 is provided with the detection circuit 48. The control substrate 121 is provided with the control circuit 122 and the power supply circuit 123. The control circuit 122 is, for example, a field-programmable gate array (FPGA). The control circuit 122 supplies control signals to the sensor 10, the gate line drive circuit 15, and the signal line selection circuit 16 to control a detection operation of the sensor 10. The control circuit 122 supplies control signals to the first and the second light sources 61 and 62 to control lighting and non-lighting of the first and the second light sources 61 and 62. The power supply circuit 123 supplies voltage signals including, for example, a sensor power supply signal (sensor power supply voltage) VDDSNS (refer to
The sensor base member 21 has a detection area AA and a peripheral area GA. The detection area AA is an area provided with a plurality of optical sensors PD (refer to
The gate line drive circuit 15 and the signal line selection circuit 16 are provided in the peripheral area GA. Specifically, the gate line drive circuit 15 is provided in an area extending along a second direction Dy in the peripheral area GA. The signal line selection circuit 16 is provided in an area extending along a first direction Dx in the peripheral area GA, and is provided between the sensor 10 and the detection circuit 48.
The first direction Dx is one direction in a plane parallel to the sensor base member 21. The second direction Dy is one direction in the plane parallel to the sensor base member 21, and is a direction orthogonal to the first direction Dx. The second direction Dy may non-orthogonally intersect the first direction Dx.
The first light sources 61 are provided on the first light source base member 51, and are arranged along the second direction Dy. The second light sources 62 are provided on the second light source base member 52, and are arranged along the second direction Dy. The first light source base member 51 and the second light source base member 52 are electrically coupled, through respective terminals 124 and 125, provided on the control substrate 121, to the control circuit 122 and the power supply circuit 123.
For example, inorganic light-emitting diodes (LEDs) or organic electroluminescent (EL) diodes (organic light-emitting diodes(OLEDs)) are used as the first and the second light sources 61 and 62. The first and the second light sources 61 and 62 emit first light and second light, respectively, having different wavelengths.
The first light emitted from the first light sources 61 is mainly reflected on a surface of an object to be detected, such as a finger Fg, and is incident on the sensor 10. As a result, the sensor 10 can detect a fingerprint by detecting a shape of asperities on the surface of the finger Fg or the like. The second light emitted from the second light sources 62 is mainly reflected in the finger Fg or the like, or transmitted through the finger Fg or the like, and is incident on the sensor 10. As a result, the sensor 10 can detect information on a living body in the finger Fg or the like. Examples of the information on the living body include a pulse wave, pulsation, and a vascular image of the finger Fg or a palm. That is, the detection device 1 may be configured as a fingerprint detection device to detect a fingerprint or a vein detection device to detect a vascular pattern of, for example, veins.
The first light may have a wavelength of from 500 nm to 600 nm, for example, a wavelength of approximately 550 nm, and the second light may have a wavelength of from 780 nm and 950 nm, for example, a wavelength of approximately 850 nm. In this case, the first light is blue or green visible light, and the second light is infrared light. The sensor 10 can detect the fingerprint based on the first light emitted from the first light sources 61. The second light emitted from the second light sources 62 is reflected in the object to be detected such as the finger Fg, or transmitted through or absorbed by the finger Fg or the like, and is incident on the sensor 10. As a result, the sensor 10 can detect the pulse wave or the vascular image (vascular pattern) as the information on the living body in the finger Fg or the like.
Alternatively, the first light may have a wavelength of from 600 nm to 700 nm, for example, approximately 660 nm, and the second light may have a wavelength of from 780 nm and 900 nm, for example, approximately 850 nm. In this case, the sensor 10 can detect a blood oxygen saturation level in addition to the pulse wave, the pulsation, and the vascular image as the information on the living body based on the first light emitted from the first light sources 61 and the second light emitted from the second light sources 62. Thus, the detection device 1 includes the first and the second light sources 61 and 62, and therefore, can detect the various information on the living body by performing the detection based on the first light and the detection based on the second light.
The arrangement of the first and the second light sources 61 and 62 illustrated in
The sensor 10 includes the optical sensors PD. Each of the optical sensors PD included in the sensor 10 is a photodiode, and outputs an electrical signal corresponding to light emitted thereto as a detection signal Vdet to the signal line selection circuit 16. The sensor 10 performs the detection in response to a gate drive signal Vgcl supplied from the gate line drive circuit 15.
The detection controller 11 is a circuit that supplies respective control signals to the gate line drive circuit 15, the signal line selection circuit 16, and the detector 40 to control operations of these components. The detection controller 11 supplies various control signals including, for example, a start signal STV, a clock signal CK, and a reset signal RST1 to the gate line drive circuit 15. The detection controller 11 also supplies various control signals including, for example, a selection signal ASW to the signal line selection circuit 16. The detection controller 11 supplies various control signals to the first and the second light sources 61 and 62 to control the lighting and the non-lighting of each group of the first and the second light sources 61 and 62.
The gate line drive circuit 15 is a circuit that drives a plurality of gate lines GCL (refer to
The signal line selection circuit 16 is a switch circuit that sequentially or simultaneously selects a plurality of signal lines SGL (refer to
The detector 40 includes the detection circuit 48, a signal processor (signal processing circuit) 44, a coordinate extractor (coordinate extraction circuit) 45, a storage (storage circuit) 46, a detection timing controller (detection timing control circuit) 47, an image processor (image processing circuit) 49, and an output processor (output processing circuit) 50. Based on a control signal supplied from the detection controller 11, the detection timing controller 47 controls the detection circuit 48, the signal processor 44, the coordinate extractor 45, and the image processor 49 so as to operate in synchronization with one another.
The detection circuit 48 is, for example, an analog front-end (AFE) circuit. The detection circuit 48 is a signal processing circuit having functions of at least a detection signal amplifier 42 and an analog-to-digital (A/D) converter 43. The detection signal amplifier 42 amplifies the detection signals Vdet. The A/D converter 43 converts analog signals output from the detection signal amplifier 42 into digital signals.
The signal processor 44 is a logic circuit that detects a predetermined physical quantity received by the sensor 10 based on an output signal of the detection circuit 48. The signal processor 44 can detect the asperities on the surface of the finger Fg or the palm based on the signals from the detection circuit 48 when the finger Fg is in contact with or in proximity to a detection surface. The signal processor 44 can also detect the information on the living body based on the signals from the detection circuit 48. Examples of the information on the living body include the vascular image, the pulse wave, the pulsation, and the blood oxygen level of the finger Fg or the palm.
The signal processor 44 may also perform processing of acquiring the detection signals Vdet (information on the living body) simultaneously detected by the optical sensors PD, and averaging the detection signals Vdet. In this case, the detector 40 can perform stable detection by reducing measurement errors caused by noise or relative positional misalignment between the object to be detected, such as the Fg finger, and the sensor 10.
The storage 46 temporarily stores therein signals calculated by the signal processor 44. The storage 46 may be, for example, a random-access memory (RAM) or a register circuit.
The coordinate extractor 45 is a logic circuit that obtains detected coordinates of the asperities on the surface of the finger or the like when the contact or the proximity of the finger is detected by the signal processor 44. The coordinate extractor 45 is the logic circuit that also obtains detected coordinates of blood vessels of the finger Fg or the palm. The image processor 49 combines the detection signals Vdet output from the respective optical sensors PD of the sensor 10 to generate two-dimensional information indicating the shape of the asperities on the surface of the finger Fg or the like and two-dimensional information indicating the shape of the blood vessels of the finger Fg or the palm. The coordinate extractor 45 may output the detection signals Vdet as sensor output voltages Vo instead of calculating the detected coordinates. A case can be considered where the detector 40 does not include the coordinate extractor 45 and the image processor 49.
The output processor 50 serves as a processor that performs processing based on the outputs from the optical sensors PD. Specifically, the output processor 50 of the present embodiment outputs the sensor output voltages Vo including at least the pulse wave data based on at least the detection signals Vdet acquired through the signal processor 44. In the present embodiment, the signal processor 44 outputs data indicating a variation (amplitude) in output voltage of the detection signal Vdet of each of the optical sensors PD (to be described later), and the output processor 50 determines which outputs are to be employed as the sensor output voltages Vo. However, the signal processor 44 or the output processor 50 may perform both these operations. The output processor 50 may include, for example, the detected coordinates obtained by the coordinate extractor 45 and the two-dimensional information generated by the image processor 49 in the sensor output voltages Vo. The function of the output processor 50 may be integrated into another component (such as the image processor 49).
The following describes a circuit configuration example of the detection device 1.
The gate lines GCL extend in the first direction Dx, and are each coupled to the partial detection areas PAA arranged in the first direction Dx. A plurality of gate lines GCL(1), GCL(2), . . . , GCL(8) are arranged in the second direction Dy, and are each coupled to the gate line drive circuit 15. In the following description, the gate lines GCL(1), GCL(2), . . . , GCL(8) will each be simply referred to as the gate line GCL when they need not be distinguished from one another. For ease of understanding of the description,
The signal lines SGL extend in the second direction Dy, and are each coupled to the optical sensors PD of the partial detection areas PAA arranged in the second direction Dy. A plurality of signal lines SGL(1), SGL(2), . . . , SGL(12) are arranged in the first direction Dx, and are each coupled to the signal line selection circuit 16 and a reset circuit 17. In the following description, the signal lines SGL(1), SGL(2), . . . , SGL(12) will each be simply referred to as the signal line SGL when they need not be distinguished from one another.
For ease of understanding of the description, 12 of the signal lines SGL are illustrated. However, this is merely an example, and N signal lines SGL (where N is 12 or larger, and is, for example, equal to 252) may be arranged. In
The gate line drive circuit 15 receives the various control signals such as the start signal STV, the clock signal CK, and the reset signal RST1 from the control circuit 122 (refer to
The gate line drive circuit 15 may perform different driving for each of detection modes including the detection of the fingerprint and the detection of different items of the information on the living body (such as the pulse wave, the pulsation, the blood vessel image, and the blood oxygen level). For example, the gate line drive circuit 15 may drive more than one of the gate lines GCL collectively.
The signal line selection circuit 16 includes a plurality of selection signal lines Lsel, a plurality of output signal lines Lout, and third switching elements TrS. The third switching elements TrS are provided corresponding to the signal lines SGL. Six signal lines SGL(1), SGL(2), . . . , SGL(6) are coupled to a common output signal line Lout1. Six signal lines SGL(7), SGL(8), . . . , SGL(12) are coupled to a common output signal line Lout2. The output signal lines Lout1 and Lout2 are each coupled to the detection circuit 48.
The signal lines SGL(1), SGL(2), . . . , SGL(6) are grouped into a first signal line block, and the signal lines SGL(7), SGL(8), . . . , SGL(12) are grouped into a second signal line block. The selection signal lines Lsel are coupled to the gates of the respective third switching elements TrS included in one of the signal line blocks. One of the selection signal lines Lsel is coupled to the gates of the third switching elements TrS in the signal line blocks.
The control circuit 122 (refer to
As illustrated in
The control circuit 122 supplies a reset signal RST2 to the reset signal line Lrst. This operation turns on the fourth switching elements TrR to electrically couple the signal lines SGL to the reference signal line Lvr. The power supply circuit 123 supplies a reference signal COM to the reference signal line Lvr. This operation supplies the reference signal COM to a capacitive element Ca (refer to
The first switching elements Tr are provided corresponding to the optical sensors PD. Each of the first switching elements Tr includes a thin-film transistor, and in this example, includes an n-channel metal oxide semiconductor (MOS) thin-film transistor (TFT).
The gates of the first switching elements Tr belonging to the partial detection areas PAA arranged in the first direction Dx are coupled to the gate line GCL. The sources of the first switching elements Tr belonging to the partial detection areas PAA arranged in the second direction Dy are coupled to the signal line SGL. The drain of the first switching element Tr is coupled to the cathode of the optical sensor PD and the capacitive element Ca.
The anode of the optical sensor PD is supplied with the sensor power supply signal VDDSNS from the power supply circuit 123. The signal line SGL and the capacitive element Ca are supplied with the reference signal COM that serves as an initial potential of the signal line SGL and the capacitive element Ca from the power supply circuit 123.
When the partial detection area PAA is irradiated with light, a current corresponding to the amount of the light flows through the optical sensor PD. As a result, an electric charge is stored in the capacitive element Ca. After the first switching element Tr is turned on, a current corresponding to the electric charge stored in the capacitive element Ca flows through the signal line SGL. The signal line SGL is coupled to the detection circuit 48 through a corresponding one of the third switching elements TrS of the signal line selection circuit 16. Thus, the detection device 1 can detect a signal corresponding to the amount of the light received by the optical sensor PD for each of the partial detection areas PAA or for each block unit PAG.
During a read period Pdet (refer to
The following describes a configuration of the optical sensor PD.
The TFT layer 22 is provided with circuits such as the gate line drive circuit 15 and the signal line selection circuit 16 described above. The TFT layer 22 is also provided with TFTs, such as the first switching elements Tr, and various types of wiring, such as the gate lines GCL and the signal lines SGL. The sensor base member 21 and the TFT layer 22 serve as a drive circuit board that drives the sensor for each predetermined detection area, and are also called a backplane or an array substrate.
The insulating layer 23 is an organic insulating layer and is provided on the TFT layer 22. The insulating layer 23 is a planarizing layer that planarizes asperities formed by the first switching elements Tr and various conductive layers formed in the TFT layer 22.
The optical sensor PD is provided on the insulating layer 23. The optical sensor PD includes a lower electrode 35, an electron transport layer 33, an active layer 31, a hole transport layer 32, and an upper electrode 34, which are stacked in this order in a direction orthogonal to the first surface S1 of the sensor base member 21.
The lower electrode 35 is provided on the insulating layer 23 and is electrically coupled to the first switching element Tr in the TFT layer 22 through a contact hole (not illustrated). The lower electrode 35 is the cathode of the optical sensor PD and is an electrode for reading the detection signal Vdet. The lower electrode 35 is formed of, for example, a light-transmitting conductive material such as indium tin oxide (ITO).
The active layer 31 changes in characteristics (for example, voltage-current characteristics and a resistance value) according to light emitted thereto. An organic material is used as a material of the active layer 31. Specifically, the active layer 31 has a bulk heterostructure in which a p-type organic semiconductor is mixed with an n-type fullerene derivative (PCBM) that is an n-type organic semiconductor. As the active layer 31, low-molecular-weight organic materials can be used including, for example, fullerene (C60), phenyl-C61-butyric acid methyl ester (PCBM), copper phthalocyanine (CuPc), fluorinated copper phthalocyanine (F16CuPc), 5,6,11,12-tetraphenyltetracene (rubrene), and perylene diimide (PDI) (derivative of perylene).
The active layer 31 can be formed by a vapor deposition process (dry process) using any of these low-molecular-weight organic materials. In this case, the active layer 31 may be, for example, a multilayered film of CuPc and F16CuPc, or a multilayered film of rubrene and C60. The active layer 31 can also be formed by a coating process (wet process). In this case, the active layer 31 is made using a material obtained by combining any of the above-listed low-molecular-weight organic materials with a high-molecular-weight organic material. As the high-molecular-weight organic material, for example, poly(3-hexylthiophene) (P3HT) and F8-alt-benzothiadiazole (F8BT) can be used. The active layer 31 can be a film made of a mixture of P3HT and PCBM, or a film made of a mixture of F8BT and PDI.
The upper electrode 34 is the anode of the optical sensor PD and is an electrode for supplying the power supply signal VDDSNS to the photoelectric conversion layers. The upper electrode 34 faces the lower electrode 35 with the active layer 31 interposed therebetween. For example, silver (Ag) is used as the upper electrode 34. Alternatively, the upper electrode 34 may be a metal material such as aluminum (Al) or an alloy material containing at least one or more of these metal materials.
The electron transport layer 33 and the hole transport layer 32 are provided to facilitate holes and electrons generated in the active layer 31 to reach the upper electrode 34 or the lower electrode 35. The electron transport layer 33 is provided between the lower electrode 35 and the active layer 31 in the direction orthogonal to the first surface S1 of the sensor base member 21. The electron transport layer 33 is in direct contact with the top of the lower electrode 35, and the active layer 31 is in direct contact with the top of the electron transport layer 33. Polyethylenimine ethoxylated (PEIE) is used as a material of the electron transport layer 33.
The hole transport layer 32 is provided between the active layer 31 and the upper electrode 34 in the direction orthogonal to the first surface S1 of the sensor base member 21. The hole transport layer 32 is in direct contact with the top of the active layer 31, and the upper electrode 34 is in direct contact with the top of the hole transport layer 32. The hole transport layer 32 is a metal oxide layer. For example, tungsten oxide (WO3) or molybdenum oxide is used as the oxide metal layer.
In the present embodiment, the hole transport layer 32 formed of tungsten oxide that is a metal oxide is provided between the active layer 31 formed of an organic semiconductor material and the upper electrode 34 formed of a metal material. This configuration can improve the adhesion between the active layer 31 and the upper electrode 34 as compared with a configuration in which the hole transport layer 32 is formed of a polythiophene-based conductive polymer (PEDOT:PSS), for example. This configuration allows the detection device 1 to be configured as a flexible sensor that can restrain the upper electrode 34 from peeling off, and is resistant to bending.
The sealing layer 25 is provided so as to cover the optical sensor PD. More specifically, the sealing layer 25 is provided above the upper electrode 34 with the intermediate layer 24 interposed therebetween. The material of the sealing layer 25 is aluminum oxide (Al2O3). This configuration allows the detection device 1 to seal the optical sensor PD better than in a case of using parylene as the sealing layer 25. ITO is used as a material of the intermediate layer 24. The intermediate layer 24 can improve the adhesion between the upper electrode 34 and the sealing layer 25.
The protective layer 29 is provided so as to cover the sealing layer 25. For example, a resin film is used as the protective layer 29. The protective layer 29 is provided to protect the optical sensor PD. The material of the protective layer 29 is not limited to a resin film, and other materials may be used.
In the present embodiment, the configuration has been described in which the light L6 is applied to the optical sensor PD from the second surface S2 side. However, the configuration may be such that the light L6 is applied to the optical sensor PD from the first surface S1 side. In this case, a light-transmitting conductive material such as ITO is used as the upper electrode 34, and a metal material such as silver is used as the lower electrode 35.
The following describes an operation example of the detection device 1.
During the reset period Prst, the gate line drive circuit 15 sequentially selects each of the gate lines GCL based on the start signal STV, the clock signal CK, and the reset signal RST1. The gate line drive circuit 15 sequentially supplies the gate drive signals Vgcl {Vgcl(1), . . . , Vgcl(M)} to the gate lines GCL. The gate drive signal Vgcl has a pulsed waveform having a power supply voltage VDD serving as a high-level voltage and a power supply voltage VSS serving as a low-level voltage. In
Thus, during the reset period Prst, the capacitive elements Ca of all the partial detection areas PAA are sequentially electrically coupled to the signal lines SGL, and are supplied with the reference signal COM. As a result, the capacitance of the capacitive elements Ca is reset. The capacitance of the capacitive elements Ca of some of the partial detection areas PAA can be reset by partially selecting the gate lines and the signal lines SGL.
Examples of the method of controlling the exposure include a method of controlling the exposure during non-selection of the gate lines and a method of always controlling the exposure. In the method of controlling the exposure during non-selection of the gate lines, the gate drive signals {Vgcl(1), . . . , Vgcl(M)} are sequentially supplied to all the gate lines GCL coupled to the optical sensors PD serving as the detection targets, and all the optical sensors PD serving as the detection targets are supplied with the reset voltage. Then, after all the gate lines GCL coupled to the optical sensors PD serving as the detection targets are set to a low voltage (the first switching elements Tr are turned off), the exposure starts and the exposure is performed during the exposure period Pex. After the exposure ends, the gate drive signals {Vgcl(1), . . . , Vgcl(M)} are sequentially supplied to the gate lines GCL coupled to the optical sensors PD serving as the detection targets as described above, and reading is performed during the read period Pdet. In the method of always controlling the exposure, the control for performing the exposure is also performed during the reset period Prst and the read period Pdet (the exposure is always controlled). In this case, the actual exposure period Pex(1) starts immediately after the gate drive signal Vgcl(1) supplied to the gate line GCL becomes L, H, and then L during the reset period Prst. The actual exposure periods Pex {(1), . . . , (M)} are periods during which the capacitive elements Ca are charged from the optical sensors PD. The electric charge stored in the capacitive element Ca during the reset period Prst causes a reverse directional current (from cathode to anode) to flow through the optical sensor PD due to light irradiation, and the potential difference in the capacitive element Ca decreases. The start timing and the end timing of the actual exposure periods Pex(1), . . . , Pex(M) are different among the partial detection areas PAA corresponding to the gate lines GCL. Each of the exposure periods Pex(1), . . . , Pex(M) starts when the gate drive signal Vgcl changes from the power supply voltage VDD serving as the high-level voltage to the power supply voltage VSS serving as the low-level voltage during the reset period Prst. Each of the exposure periods Pex(1), . . . , Pex(M) ends when the gate drive signal Vgcl changes from the power supply voltage VSS to the power supply voltage VDD during the read period Pdet. The lengths of the exposure time of the exposure periods Pex(1), . . . , Pex(M) are equal.
In the method of controlling the exposure during non-selection of the gate lines, a current flows depending on the light received by the optical sensor PD in each of the partial detection areas PAA during the exposure periods Pex {(1) . . . (M)}. As a result, an electric charge is stored in each of the capacitive elements Ca.
At a time before the read period Pdet starts, the control circuit 122 sets the reset signal RST2 to a low-level voltage. This operation stops the operation of the reset circuit 17. The reset signal may be set to a high-level voltage only during the reset period Prst. During the read period Pdet, the gate line drive circuit 15 sequentially supplies the gate drive signals Vgcl(1) . . . , Vgcl(M) to the gate lines GCL in the same manner as during the reset period Prst.
Specifically, the gate line drive circuit 15 supplies the gate drive signal Vgcl(1) at the high-level voltage (power supply voltage VDD) to the gate line GCL(1) during a period V(1). The control circuit 122 sequentially supplies the selection signals ASW1, . . . , ASW6 to the signal line selection circuit 16 during a period in which the gate drive signal Vgcl(1) is at the high-level voltage (power supply voltage VDD). This operation sequentially or simultaneously couples the signal lines SGL of the partial detection areas PAA selected by the gate drive signal Vgcl(1) to the detection circuit 48. As a result, the detection signal Vdet for each of the partial detection areas PAA is supplied to the detection circuit 48.
In the same manner, the gate line drive circuit 15 supplies the gate drive signals Vgcl(2), . . . , Vgcl(M−1), Vgcl(M) at the high-level voltage to gate lines GCL(2), . . . , GCL(M−1), GCL(M) during periods V(2), . . . , V(M−1), V(M), respectively. That is, the gate line drive circuit 15 supplies the gate drive signal Vgcl to the gate line GCL during each of the periods V(1), V(2), . . . , V(M−1), V(M). The signal line selection circuit 16 sequentially selects each of the signal lines SGL based on the selection signal ASW in each period in which the gate drive signal Vgcl is set to the high-level voltage. The signal line selection circuit 16 sequentially couples each of the signal lines SGL to one detection circuit 48. Thus, the detection device 1 can output the detection signals Vdet of all the partial detection areas PAA to the detection circuit 48 during the read period Pdet.
As illustrated in
Specifically, after the period t4 occurs in which the switch SSW is on, the electric charge moves from the capacitor (capacitive element Ca) of the partial detection area PAA to the capacitor (capacitive element Cb) of the detection signal amplifier 42 of the detection circuit 48. At this time, the non-inverting input (+) of the detection signal amplifier 42 is set to the reference potential (Vref) voltage (for example, 0.75 V). As a result, the output voltage (Vout) of the third switching element TrS is also set to the reference potential (Vref) due to the imaginary short-circuit between the input ends of the detection signal amplifier 42. The voltage of the capacitive element Cb is set to a voltage corresponding to the electric charge stored in the capacitor (capacitive element Ca) of the partial detection area PAA at a location where the third switching element TrS is turned on in response to the selection signal ASW(k). After the output voltage (Vout) of the third switching element TrS is set to the reference potential (Vref) due to the imaginary short-circuit, the output voltage of the detection signal amplifier 42 reaches a voltage corresponding to the capacitance of the capacitive element Cb, and this output voltage is read by the A/D converter 43. The voltage of the capacitive element Cb is, for example, a voltage between two electrodes provided on a capacitor constituting the capacitive element Cb.
The period t1 is, for example, 20 μs. The period t2 is, for example, 60 μs. The period t3 is, for example, 44.7 μs. The period t4 is, for example, 0.98 μs.
Although
The following describes relations between the thickness of the active layer 31 and characteristics of the optical sensor PD.
As illustrated in
As illustrated in
As described above, the thickness of the active layer 31 is 500 nm or smaller, more preferably from 140 nm to 500 nm. As a result, the detection device 1 can reduce the influence of the photocurrent (or leakage current) of the optical sensor PD while maintaining the sensor capacitance, and can well obtain the sensor output voltage.
As described above, the detection device 1 of the present embodiment is a detection device including the optical sensors PD arranged on the substrate (sensor base member 21). In each of the optical sensors PD, the lower electrode 35, the electron transport layer 33, the active layer 31, the hole transport layer 32, and the upper electrode 34 are stacked in the direction orthogonal to the surface of the substrate in the order as listed. The active layer 31 contains an organic semiconductor. The hole transport layer 32 contains tungsten oxide and is provided on the active layer 31 so as to be in contact therewith.
The upper electrode 34 contains silver, and the active layer 31 contains a p-type organic semiconductor and an n-type fullerene derivative that is an n-type organic semiconductor. The sealing layer 25 contains aluminum oxide, and the electron transport layer 33 contains polyethylenimine ethoxylated (PEIE).
With this configuration, since the hole transport layer 32 is formed of tungsten oxide that is an inorganic material, the adhesion between the active layer 31 and the upper electrode 34 can be improved. This configuration allows the detection device 1 to be configured as a flexible sensor that can restrain the upper electrode 34 from peeling off, and is resistant to bending.
As illustrated in
A sealing layer 25A is configured by stacking inorganic films 26 and 28 and an organic film 27. The inorganic film 26, the organic film 27, and the inorganic film 28 are stacked in the direction orthogonal to the sensor base member 21 in the order as listed. The inorganic films 26 and 28 are inorganic insulating films of, for example, silicon nitride (SiN). The organic film 27 is, for example, a resin material. In the present embodiment, the sealing layer 25A is multi-layered to enable good sealing of the optical sensor PD.
The configuration of the second embodiment can be combined with that of the first embodiment described above. For example, the sealing layer 25A of the second embodiment may be provided instead of the sealing layer 25 illustrated in
While the preferred embodiments of the present disclosure have been described above, the present disclosure is not limited to the embodiments described above. The content disclosed in the embodiments is merely an example, and can be variously modified within the scope not departing from the gist of the present disclosure. Any modifications appropriately made within the scope not departing from the gist of the present disclosure also naturally belong to the technical scope of the present disclosure. At least one of various omissions, substitutions, and changes of the components can be made without departing from the gist of the embodiments and the modifications described above.
Number | Date | Country | Kind |
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2020-127338 | Jul 2020 | JP | national |
This application claims the benefit of priority from Japanese Patent Application No. 2020-127338 filed on Jul. 28, 2020 and International Patent Application No. PCT/JP2021/026599 filed on Jul. 15, 2021, the entire contents of which are incorporated herein by reference.
Number | Date | Country | |
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Parent | PCT/JP2021/026599 | Jul 2021 | US |
Child | 18101183 | US |