Detection device

Abstract

This detection device has a first detection circuit that includes a first photodiode having sensitivity to first light and a second photodiode having sensitivity to second light and a second detection circuit that includes a third photodiode having sensitivity to third light, wherein: the first photodiode and the second photodiode constitute a first detection element connected in series in opposite directions; one end of the first detection element is connected to a first signal line with a first transistor therebetween; a first drive signal is supplied to the other end of the first detection element; a cathode of the third photodiode is connected to a second signal line with a second transistor therebetween; and a second drive signal is supplied to an anode of the third photodiode.

Description

[Technical Field]

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

[0002] As an optical sensor, an OPD (organic photodiode) using an organic semiconductor material is known (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-160826 Summary of the Invention [Problem to be solved by the invention]

[0004] It has been difficult to realize a color scanner that is sensitive to different wavelengths using an OPD.

[0005] An object of the present invention is to provide a detection device using an OPD that has good detection sensitivity for different wavelengths. [Means for solving the problem]

[0006] A detection device according to one embodiment of the present invention includes a first detection circuit including a first photodiode sensitive to a first light and a second photodiode sensitive to a second light, and a second detection circuit including a third photodiode sensitive to a third light, wherein the first photodiode and the second photodiode are connected in series and in reverse directions to form a first detection element, one end of the first detection element is connected to a first signal line via a first transistor, a first drive signal is supplied to the other end of the first detection element, a cathode of the third photodiode is connected to a second signal line via a second transistor, and a second drive signal is supplied to the anode of the third photodiode. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a plan view showing a detection device according to a first embodiment. [Figure 2] FIG. 2 is a block diagram showing an example of the configuration of the detection device according to the first embodiment. [Figure 3] FIG. 3 is a circuit diagram showing the detection device. [Figure 4] FIG. 4 is a circuit diagram showing one pixel and a detection circuit. [Figure 5] FIG. 5 is a cross-sectional view schematically showing a cross section of the detection device according to the first embodiment. [Figure 6] FIG. 6 is a circuit diagram showing one pixel and a detection circuit of the detection device according to the second embodiment. [Figure 7] FIG. 7 is a circuit diagram showing one pixel and a detection circuit of the detection device according to the third embodiment. [Figure 8] FIG. 8 is a cross-sectional view schematically showing a cross section of a detection device according to a fourth embodiment. [Figure 9] FIG. 9 is a cross-sectional view schematically showing a cross section of a detection device according to a fifth embodiment. [Figure 10] FIG. 10 is a cross-sectional view schematically showing a cross section of a detection device according to a sixth embodiment. [Figure 11] FIG. 11 is a cross-sectional view schematically showing a cross section of a detection device according to the seventh embodiment. [Figure 12] FIG. 12 is a diagram showing an example of an electronic device to which the detection device is applied. DETAILED DESCRIPTION OF THE INVENTION

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

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

[0010] (First embodiment) FIG. 1 is a plan view showing a detection device according to a first embodiment. The detection device 1 of this embodiment has an OPD (organic photodiode) as an optical sensor and is used in color scanners, digital cameras, and the like that capture images of a detection target. As shown in FIG. 1, the detection device 1 includes a substrate 21, a sensor unit 10, a gate line driving circuit 15, a signal line selection circuit 16, a detection circuit 48, a control circuit 122, a power supply circuit 123, a first light source substrate 51, a second light source substrate 52, a first light source 53, and a second light source 54. The first light source substrate 51 is provided with a plurality of first light sources 53. The second light source substrate 52 is provided with a plurality of second light sources 54.

[0011] A control board 121 is electrically connected to the substrate 21 via a wiring board 71. The wiring board 71 is, for example, a flexible printed circuit board or a rigid board. The detection circuit 48 is provided on the wiring board 71. The control board 121 is provided with a control circuit 122 and a power supply circuit 123. The control circuit 122 is, for example, an FPGA (Field Programmable Gate Array). The control circuit 122 supplies control signals to the sensor unit 10, the gate line driving circuit 15, and the signal line selection circuit 16 to control the detection operation of the sensor unit 10. The control circuit 122 also supplies control signals to the first light source 53 and the second light source 54 to control whether the first light source 53 and the second light source 54 are turned on or off. The power supply circuit 123 controls the sensor power supply signal (drive signal, power supply voltage) Voltage signals such as VDDSNS (see FIG. 4) are supplied to the sensor unit 10, the gate line driving circuit 15, and the signal line selection circuit 16. The power supply circuit 123 also supplies a power supply voltage to the first light source 53 and the second light source .

[0012] The substrate 21 has a detection area AA and a peripheral area GA. The detection area AA is an area where a plurality of photodiodes PD (see FIG. 4) of the sensor unit 10 are provided. The peripheral area GA is an area between the periphery of the detection area AA and the outer edge of the substrate 21, where a plurality of photodiodes PD are not provided.

[0013] The gate line driving circuit 15 and the signal line selection circuit 16 are provided in the peripheral area GA. Specifically, the gate line driving circuit 15 is provided in a region of the peripheral area GA extending along the second direction Dy. The signal line selection circuit 16 is provided in a region of the peripheral area GA extending along the first direction Dx, and is provided between the sensor unit 10 and the detection circuit 48.

[0014] In the following description, the first direction Dx is a direction in a plane parallel to the substrate 21. The second direction Dy is a direction in a plane parallel to the substrate 21, and is a direction perpendicular to the first direction Dx. The second direction Dy may intersect with the first direction Dx without being perpendicular thereto. Furthermore, "plan view" refers to the positional relationship when viewed from a direction perpendicular to the substrate 21.

[0015] The plurality of first light sources 53 are provided on the first light source substrate 51 and arranged along the second direction Dy. The plurality of second light sources 54 are provided on the second light source substrate 52 and arranged along the second direction Dy. The first light source substrate 51 and the second light source substrate 52 are electrically connected to the control circuit 122 and the power supply circuit 123 via terminal portions 124 and 125 provided on the control board 121, respectively.

[0016] The first light sources 53 and the second light sources 54 may be, for example, inorganic light emitting diodes (LEDs) or organic light emitting diodes (OLEDs). The first light sources 53 and the second light sources 54 each include a plurality of LEDs that emit red (R), green (G), and blue (B) light. The first light sources 53 and the second light sources 54 may also include a plurality of LEDs that emit white light. The light emitted from the first light sources 53 and the second light sources 54 is reflected by the surface of the object to be detected and enters the sensor unit 10. This allows the sensor unit 10 to capture an image of the object to be detected. The first light sources 53 and the second light sources 54 may be omitted.

[0017] Fig. 2 is a block diagram showing an example of the configuration of the detection device according to the first embodiment. As shown in Fig. 2, the detection device 1 further includes a detection control circuit 11 and a detection unit 40. Some or all of the functions of the detection control circuit 11 are included in a control circuit 122. In addition, some or all of the functions of the detection unit 40 other than the detection circuit 48 are included in the control circuit 122.

[0018] The sensor unit 10 has a plurality of photodiodes PD. The photodiodes PD of the sensor unit 10 output electrical signals corresponding to the incident light as output signals Vdet to the signal line selection circuit 16. The sensor unit 10 also performs detection in accordance with gate drive signals Vgcl supplied from the gate line drive circuit 15.

[0019] The detection control circuit 11 is a circuit that supplies control signals to the gate line drive circuit 15, the signal line selection circuit 16, and the detection unit 40, respectively, and controls their operations. The detection control circuit 11 supplies various control signals, such as a start signal STV, a clock signal CK, and a reset signal RST1, to the gate line drive circuit 15. The detection control circuit 11 also supplies various control signals, such as a selection signal ASW, to the signal line selection circuit 16. The detection control circuit 11 also supplies various control signals to the first light source 53 and the second light source 54, and controls the lighting and non-lighting of each.

[0020] The gate line driving circuit 15 is a circuit that drives multiple gate lines GCL (see FIG. 3) based on various control signals. The gate line driving circuit 15 selects the multiple gate lines GCL sequentially or simultaneously and supplies a gate driving signal Vgcl to the selected gate lines GCL. In this way, the gate line driving circuit 15 selects multiple photodiodes PD connected to the gate lines GCL.

[0021] The signal line selection circuit 16 is a switch circuit that sequentially or simultaneously selects a plurality of signal lines SGL (see FIG. 3). The signal line selection circuit 16 is, for example, a multiplexer. The signal line selection circuit 16 connects the selected signal line SGL to the detection circuit 48 based on a selection signal ASW supplied from the detection control circuit 11. As a result, the signal line selection circuit 16 outputs the output signal Vdet of the photodiode PD to the detection unit 40.

[0022] The detection unit 40 includes a detection circuit 48, a signal processing circuit 44, a memory circuit 46, a detection timing control circuit 47, an image processing circuit 49, and an output processing circuit 50. The detection timing control circuit 47 controls the detection circuit 48, the signal processing circuit 44, and the image processing circuit 49 based on a control signal supplied from the detection control circuit 11 so that they operate in synchronization with each other.

[0023] The detection circuit 48 is, for example, an analog front end (AFE). The detection circuit 48 is a signal processing circuit having at least the functions of a detection signal amplifier circuit 42 and an A / D conversion circuit 43. The detection signal amplifier circuit 42 amplifies the output signal Vdet. The A / D conversion circuit 43 converts the analog signal output from the detection signal amplifier circuit 42 into a digital signal. The detection circuit 48 outputs red (R), green (G), and blue (B) color signals for each pixel PX.

[0024] The signal processing circuit 44 performs a predetermined correction on the color signals for red (R), green (G), and blue (B) received from the detection circuit 48. For example, the signal processing circuit 44 performs a predetermined correction on the color signals to suppress variations in the intensity of light emitted from the first light source 53 and the second light source 54 within the detection area AA and variations in the detection sensitivity of the photodiodes PD. The signal processing circuit 44 may also acquire output signals Vdet simultaneously detected by multiple photodiodes PD and average these signals. In this case, the detection unit 40 can suppress measurement errors caused by noise and relative positional misalignment between the object to be detected and the sensor unit 10, enabling stable detection.

[0025] The memory circuit 46 temporarily stores the signals calculated by the signal processing circuit 44. The memory circuit 46 may be, for example, a RAM (Random Access Memory), a register circuit, or the like.

[0026] The image processing circuit 49 generates two-dimensional information of an image by combining the output signals Vdet output from the photodiodes PD of the sensor unit 10. The image processing circuit 49 may output the output signal Vdet as the sensor output voltage Vo without calculating image data. The image processing circuit 49 may not be included in the detection unit 40.

[0027] The output processing circuit 50 functions as a processing unit that performs processing based on outputs from the multiple photodiodes PD. The output processing circuit 50 may include the two-dimensional information generated by the image processing circuit 49 in the sensor output voltage Vo. Furthermore, the function of the output processing circuit 50 may be integrated into another configuration (for example, the image processing circuit 49).

[0028] Next, an example of the circuit configuration of the detection device 1 will be described. FIG. 3 is a circuit diagram showing the detection device. As shown in FIG. 3, the sensor unit 10 has a plurality of pixels PX arranged in a matrix. Each of the plurality of pixels PX is provided with a photodiode PD. The plurality of pixels PX including the photodiode PD are arranged on a substrate 21. The photodiode PD is an OPD (organic photodiode) using an organic semiconductor. The detailed configuration of the pixel PX will be described later with reference to FIG. 4.

[0029] The gate line GCL extends in a first direction Dx and is connected to a plurality of pixels PX arranged in the first direction Dx. Furthermore, a plurality of gate lines GCL(1), GCL(2), ..., GCL(8) are arranged in a second direction Dy and are each connected to a gate line driving circuit 15. In the following description, when it is not necessary to distinguish between the plurality of gate lines GCL(1), GCL(2), ..., GCL(8), they will simply be referred to as gate lines GCL. Furthermore, for ease of understanding, eight gate lines GCL are shown in FIG. 3, but this is merely an example, and M gate lines GCL (M is 8 or more, for example, M=256) may be arranged.

[0030] The signal line SGL extends in the second direction Dy and is connected to the photodiodes PD of the plurality of pixels PX arranged in the second direction Dy. The plurality of signal lines SGL(1), SGL(2), ..., SGL(12) are arranged in the first direction Dx and are each connected to the signal line selection circuit 16 and the reset circuit 17. In the following description, when it is not necessary to distinguish between the plurality of signal lines SGL(1), SGL(2), ..., SGL(12), they will simply be referred to as signal lines SGL.

[0031] For ease of understanding, 12 signal lines SGL are shown, but this is merely an example, and N signal lines SGL (N is 12 or more, for example, N=252) may be arranged. In addition, in Fig. 3, the sensor unit 10 is provided between the signal line selection circuit 16 and the reset circuit 17. However, this is not limiting, and the signal line selection circuit 16 and the reset circuit 17 may be connected to ends of the signal lines SGL in the same direction.

[0032] The gate line driving circuit 15 receives various control signals, such as a start signal STV, a clock signal CK, and a reset signal RST1, from the control circuit 122 (see FIG. 1). Based on the various control signals, the gate line driving circuit 15 sequentially selects multiple gate lines GCL(1), GCL(2), ..., GCL(8) in a time-division manner. The gate line driving circuit 15 supplies a gate driving signal Vgcl to the selected gate line GCL. As a result, the gate driving signal Vgcl is supplied to multiple transistors Tr (first transistor Tr1 and second transistor Tr2 (see FIG. 4)) connected to the gate line GCL, and multiple pixels PX arranged in the first direction Dx are selected as detection targets.

[0033] The signal line selection circuit 16 has a plurality of selection signal lines Lsel, a plurality of output signal lines Lout, and a third transistor TrS. The plurality of third transistors TrS are provided corresponding to the plurality of signal lines SGL, respectively. The six signal lines SGL(1), SGL(2), ..., SGL(6) are connected to a common output signal line Lout1. The six signal lines SGL(7), SGL(8), ..., SGL(12) are connected to a common output signal line Lout2. The output signal lines Lout1 and Lout2 are each connected to a detection circuit 48.

[0034] Here, the signal lines SGL(1), SGL(2), ..., SGL(6) are defined as a first signal line block, and the signal lines SGL(7), SGL(8), ..., SGL(12) are defined as a second signal line block. The multiple selection signal lines Lsel are connected to the gates of the third transistors TrS included in one signal line block. Furthermore, one selection signal line Lsel is connected to the gates of the third transistors TrS of multiple signal line blocks.

[0035] The control circuit 122 (see FIG. 1) sequentially supplies the selection signal ASW to the selection signal line Lsel. As a result, the signal line selection circuit 16 sequentially selects the signal lines SGL in one signal line block in a time-division manner through the operation of the third transistor TrS. The signal line selection circuit 16 also selects one signal line SGL in each of the multiple signal line blocks. With this configuration, the detection device 1 can reduce the number of ICs (Integrated Circuits) including the detection circuit 48 or the number of IC terminals. The signal line selection circuit 16 may also bundle multiple signal lines SGL and connect them to the detection circuit 48.

[0036] 3, the reset circuit 17 includes a reference signal line Lvr, a reset signal line Lrst, and a fourth transistor TrR. The fourth transistor TrR is provided corresponding to the plurality of signal lines SGL. The reference signal line Lvr is connected to one of the sources or drains of the plurality of fourth transistors TrR. The reset signal line Lrst is connected to the gates of the plurality of fourth transistors TrR.

[0037] The control circuit 122 supplies a reset signal RST2 to the reset signal line Lrst. This turns on the multiple fourth transistors TrR, and the multiple signal lines SGL are electrically connected to the reference signal line Lvr. The power supply circuit 123 supplies a reference potential COM to the reference signal line Lvr. This supplies the reference potential COM to the capacitive elements Ca1 and Ca2 (see FIG. 4) included in the multiple pixels PX.

[0038] FIG. 4 is a circuit diagram showing one pixel and a detection circuit. Note that FIG. 4 also shows the circuit configuration of the power supply circuit 123. As shown in FIG. 4, the pixel PX includes a first detection circuit SPX1 and a second detection circuit SPX2. The first detection circuit SPX1 and the second detection circuit SPX2 are sensitive to light in different wavelength regions. Specifically, the first detection circuit SPX1 detects a first light, which is red (R) light, and a second light, which is green (G), of the light incident on the pixel PX. The second detection circuit SPX2 detects a third light, which is blue (B) light.

[0039] The first detection circuit SPX1 includes a first photodiode PD-R sensitive to the first light, a second photodiode PD-G sensitive to the second light, a capacitance element Ca1, and a first transistor Tr1. The first photodiode PD-R and the second photodiode PD-G are connected in series in reverse directions (first detection element). Note that "connected in reverse directions" refers to a connection configuration in which the rectification characteristics of the first photodiode PD-R and the second photodiode PD-G are in reverse directions.

[0040] More specifically, the anode of the first photodiode PD-R and the anode of the second photodiode PD-G are electrically connected. One end of the first photodiode PD-R and the second photodiode PD-G connected in series, i.e., the cathode of the first photodiode PD-R, is connected to a first signal line SGL(n) via a first transistor Tr1. The other end of the first photodiode PD-R and the second photodiode PD-G connected in series, i.e., the cathode of the second photodiode PD-G, is electrically connected to a drive signal supply circuit 123a (power supply circuit 123) and is supplied with a drive signal VDDSNS (first drive signal).

[0041] The capacitive elements Ca1 and Ca2 are capacitances (sensor capacitances) formed in the photodiode PD and are equivalently connected in parallel to the photodiode PD. In the first detection circuit SPX1, one end of the capacitive element Ca1 is electrically connected to the cathode of the first photodiode PD-R, and the other end of the capacitive element Ca1 is electrically connected to the cathode of the second photodiode PD-G.

[0042] The first transistor Tr1 is provided corresponding to the photodiode PD (the first photodiode PD-R and the second photodiode PD-G). The first transistor Tr1 is configured by a thin film transistor, and in this example, is configured by an n-channel MOS (Metal Oxide Semiconductor) TFT (Thin Film Transistor).

[0043] The gate of the first transistor Tr1 is connected to the gate line GCL (see FIG. 3), the source of the first transistor Tr1 is connected to the first signal line SGL(n), and the drain of the first transistor Tr1 is connected to the cathode of the first photodiode PD-R and one end of the capacitive element Ca1.

[0044] The second detection circuit SPX2 includes a third photodiode PD-B sensitive to the third light, a capacitive element Ca2, and a second transistor Tr2. Unlike the first detection circuit SPX1, the second detection circuit SPX2 is configured with one third photodiode PD-B. The cathode of the third photodiode PD-B is connected to the second signal line SGL(n+1) via the second transistor Tr2. The anode of the third photodiode PD-B is electrically connected to the drive signal supply circuit 123a (power supply circuit 123) and is supplied with a drive signal VDDSNS (second drive signal).

[0045] In the following description, when there is no need to distinguish between the first photodiode PD-R, the second photodiode PD-G, and the third photodiode PD-B, they may be simply referred to as photodiodes PD. Also, when there is no need to distinguish between the first signal line SGL(n) and the second signal line SGL(n+1), they may be simply referred to as signal lines SGL.

[0046] In the second detection circuit SPX2, one end of the capacitance element Ca2 is electrically connected to the cathode of the third photodiode PD-B, and the other end of the capacitance element Ca2 is electrically connected to the anode of the third photodiode PD-B.

[0047] The second transistor Tr2 is provided corresponding to the third photodiode PD-B. Like the first transistor Tr1, the second transistor Tr2 is configured as a thin-film transistor. The gate of the second transistor Tr2 is connected to the gate line GCL (see FIG. 3). The source of the second transistor Tr2 is connected to the second signal line SGL(n+1). The drain of the second transistor Tr2 is connected to the cathode of the third photodiode PD-B and one end of the capacitive element Ca2.

[0048] A reference potential COM (see FIG. 3), which serves as the initial potential of the signal line SGL and each photodiode PD, is supplied from the power supply circuit 123 to the first signal line SGL(n), the second signal line SGL(n+1), the cathode of the first photodiode PD-R, and the cathode of the third photodiode PD-B. A bias voltage VB is supplied to each photodiode PD by the drive signal VDDSNS and the reference potential COM. The bias voltage VB is expressed as VB=COM-VDDSNS.

[0049] The drive signal supply circuit 123a, which supplies a drive signal VDDSNS to each photodiode PD of the first detection circuit SPX1 and the second detection circuit SPX2, includes a first voltage signal supply circuit 123H, a second voltage signal supply circuit 123L, and a switch BSW. The first voltage signal supply circuit 123H is a circuit that supplies a first voltage signal VH having a higher voltage level than the reference potential COM. The second voltage signal supply circuit 123L is a circuit that supplies a second voltage signal VL having a lower voltage level than the reference potential COM. The switch BSW is a switch element that switches the connection state between the first voltage signal supply circuit 123H and the second voltage signal supply circuit 123L and each photodiode PD of the first detection circuit SPX1 and the second detection circuit SPX2. By operating the switch BSW, the drive signal supply circuit 123a supplies the first voltage signal VH and the second voltage signal VL to each photodiode PD of the first detection circuit SPX1 and the second detection circuit SPX2 in a time-division manner. When the second photodiode PD-G is forward biased, it is desirable to set the path from the second signal line SGL(n+1) to high impedance by, for example, gating off the second transistor Tr2 or turning off the third transistor TrS connected to that path.

[0050] Specifically, in the first detection circuit SPX1, when the drive signal supply circuit 123a supplies a first voltage signal VH (VH>COM) to the cathode of the second photodiode PD-G, the first photodiode PD-R is forward-biased and the second photodiode PD-G is reverse-biased. In this case, the second photodiode PD-G detects the second light (G), and a forward current flows through the first photodiode PD-R. In other words, the first photodiode PD-R is refreshed in synchronization with the detection period during which the second photodiode PD-G performs detection. In this disclosure, the term "refresh operation" refers to an operation of returning the characteristics of the OPD to their initial states by passing a forward bias current through the photodiode PD.

[0051] Also, when a second voltage signal VL (VL < COM) is supplied from the drive signal supply circuit 123a to the cathode of the second photodiode PD-G, the first photodiode PD-R is driven in reverse bias and the second photodiode PD-G is driven in forward bias. In this case, the first photodiode PD-R detects the first light (R), a forward current flows through the second photodiode PD-G, and a refresh is performed.

[0052] In the second detection circuit SPX2, when a first voltage signal VH (VH > COM) is supplied from the drive signal supply circuit 123a to the anode of the third photodiode PD-B, for example, the second transistor Tr2 is turned off at the gate, the third photodiode PD-B is not driven in forward bias, and a refresh is not performed. Also, when a second voltage signal VL (VL < COM) is supplied from the drive signal supply circuit 123a to the anode of the third photodiode PD-B, the third photodiode PD-B is driven in reverse bias, and the third light (B) is detected.

[0053] The detection device 1 performs detection of the first light (R) by the first photodiode PD-R and detection of the second light (G) by the second photodiode PD-G in a time division manner in the first detection circuit SPX1. Also, the detection device 1 may perform detection of the third light (B) by the third photodiode PD-B in the second detection circuit SPX2 in synchronization with the detection in the first detection circuit SPX1, or may perform it in a time division manner without synchronization with the detection in the first detection circuit SPX1.

[0054] In other words, the drive signal VDDSNS (first drive signal) supplied to the first detection circuit SPX1 and the drive signal VDDSNS (second drive signal) supplied to the second detection circuit SPX2 may be supplied with signals having the same potential in synchronization, or different signals may be supplied to each. When the second photodiode PD-G is in forward bias, it is desirable to make the path from the second signal line SGL(n + 1) into a high impedance by turning off the gate of the second transistor Tr2, or turning off the third transistor TrS connected to the path, etc.

[0055] When light is irradiated onto the first detection circuit SPX1 and the second detection circuit SPX2, a current corresponding to the amount of the first light, the second light, and the third light flows through the photodiodes PD (the first photodiode PD-R, the second photodiode PD-G, and the third photodiode PD-B), and this causes a capacitance element Ca1 , Ca2 When the first transistor Tr1 or the second transistor Tr2 is turned on, a charge is accumulated in the capacitance element Ca1. or Ca2 A current flows through the signal line SGL in accordance with the charge accumulated in the signal line SGL. The signal line SGL is electrically connected to the detection circuit 48 via the third transistor TrS of the signal line selection circuit 16. This allows the detection device 1 to detect a signal corresponding to the amount of light irradiated on each photodiode PD for each pixel PX.

[0056] In the detection circuit 48, the switch SSW is turned on during the readout period, and the detection circuit 48 is connected to the signal line SGL. The current is adjusted according to the value of the current. electric Pressure The detection signal amplifier circuit 42 converts and amplifies the detected signal. A reference potential (Vref) having a fixed potential is input to the non-inverting input (+) of the detection signal amplifier circuit 42, and a signal line SGL is connected to the inverting input (-). In this embodiment, a signal equal to the reference potential COM is input as the reference potential (Vref) voltage. The signal processing circuit 44 (see FIG. 2) calculates the difference between the output signal Vdet when light is irradiated and the output signal Vdet when no light is irradiated as the sensor output voltage Vo. The detection signal amplifier circuit 42 also has a capacitance element Cb and a reset switch RSW. During the reset period, the reset switch RSW is turned on, and the charge of the capacitance element Cb is reset.

[0057] Next, a configuration example of the photodiode PD will be described. FIG. 5 is a cross-sectional view schematically showing a cross section of the detection device according to the first embodiment. As shown in FIG. 5, the first photodiode PD-R, the second photodiode PD-G, and the third photodiode PD-B are provided on the first main surface S1 of the substrate 21. The detection device 1 according to the first embodiment is a top-light-receiving type optical sensor, and light L1 is incident on the first main surface S1 side of the substrate 21.

[0058] The substrate 21 is an insulating base material, and is made of, for example, glass or a resin material. The substrate 21 is a flat-plate member having a first main surface S1 and a second main surface S2 opposite to the first main surface S1. However, the substrate 21 is not limited to a flat-plate shape and may have a curved surface. In this case, the substrate 21 may be a film-like resin.

[0059] The first photodiode PD-R includes a first organic semiconductor layer 31 that is sensitive to the first light. The second photodiode PD-G includes a second organic semiconductor layer 32 that is sensitive to the second light. In a region overlapping with the first detection circuit SPX1, the second organic semiconductor layer 32 (second photodiode PD-G) and the first organic semiconductor layer 31 (first photodiode PD-R) are stacked in this order on the first main surface S1 of the substrate 21. However, the stacking order of the second organic semiconductor layer 32 (second photodiode PD-G) and the first organic semiconductor layer 31 (first photodiode PD-R) may be reversed.

[0060] The third photodiode PD-B includes a laminated structure in which a first organic semiconductor layer 31 and a second organic semiconductor layer 32 are laminated. In a region overlapping with the second detection circuit SPX2, the second organic semiconductor layer 32, the first organic semiconductor layer 31, and a wavelength conversion layer 81 are laminated in this order on the first main surface S1 of the substrate 21. The wavelength conversion layer 81 is laminated on the light L1 incident surface side of the second organic semiconductor layer 32 and the first organic semiconductor layer 31 (on the upper surface of the first organic semiconductor layer 31 in FIG. 5). In other words, the second detection circuit SPX2 includes the third photodiode PD-B and the wavelength conversion layer 81 that converts the third light into the first light or the second light.

[0061] The first organic semiconductor layer 31 and the second organic semiconductor layer 32 are provided continuously from the region overlapping with the first detection circuit SPX1 to the region overlapping with the second detection circuit SPX2. That is, the first organic semiconductor layer 31 constituting the first photodiode PD-R and the first organic semiconductor layer 31 constituting the third photodiode PD-B are formed continuously in the same layer, and the second organic semiconductor layer 32 constituting the second photodiode PD-G and the second organic semiconductor layer 32 constituting the third photodiode PD-B are formed continuously in the same layer.

[0062] The wavelength conversion layer 81 can be a wavelength conversion film, a wavelength cut film that cuts off specific wavelength components and transmits other wavelength components, etc. For example, the wavelength conversion layer 81 converts the third light (B) component of the light L1 into the first light (R).

[0063] With this configuration, the first photodiode PD-R of the first detection circuit SPX1 outputs an output signal Vdet(R) based on the first light (R) of the light L1. The second light (G) component of the light L1 is not absorbed by the first organic semiconductor layer 31 (first photodiode PD-R) and is incident on the second organic semiconductor layer 32 (second photodiode PD-G). The second photodiode PD-G of the first detection circuit SPX1 outputs an output signal Vdet(G) based on the second light (G) of the light L1.

[0064] The first organic semiconductor layer 31 (third photodiode PD-B) of the second detection circuit SPX2 outputs an output signal Vdet(B) based on the light L1 that has been converted from third light (B) to first light (R) by the wavelength conversion layer 81.

[0065] Signal processing circuit 44 (Fig. 2The second detection circuit SPX2 (see reference 1) performs arithmetic processing of the output signals Vdet from the first photodiode PD-R, the second photodiode PD-G, and the third photodiode PD-B as necessary. For example, the second detection circuit SPX2 can subtract the output value of the output signal Vdet(R) of the first detection circuit SPX1 from the output value of the output signal Vdet(B) from the third photodiode PD-B in accordance with the transmission characteristics of the wavelength conversion layer 81 to obtain the detection value of the second detection circuit SPX2.

[0066] With this configuration, the detection device 1 can detect first light (R), second light (G), and third light (B) using the first photodiode PD-R, second photodiode PD-G, and third photodiode PD-B, respectively. The first photodiode PD-R and second photodiode PD-G are formed of a first organic semiconductor layer 31 and a second organic semiconductor layer 32 stacked on the substrate 21, and are configured as a single first detection circuit SPX1. In other words, the single first detection circuit SPX1 is sensitive to each of the first light (R) and the second light (G). The second detection circuit SPX2 is sensitive to the third light (B). While previously detecting color images required detection elements with three different sensitivities (RGB), the detection device 1 of this embodiment can detect first light (R), second light (G), and third light (B) using two detection circuits: the first detection circuit SPX1 and the second detection circuit SPX2.

[0067] (Second embodiment) 6 is a circuit diagram showing one pixel and a detection circuit of a detection device according to the second embodiment. In the following description, the same components as those described in the above embodiments are denoted by the same reference numerals, and redundant description will be omitted.

[0068] As shown in FIG. 6, in the detection device 1A according to the second embodiment, the second detection circuit SPX2 has a third photodiode PD-B and a fourth photodiode PD-A. The fourth photodiode PD-A is sensitive to light (e.g., near-infrared light) other than the first light (R), the second light (G), and the third light (B). The third photodiode PD-B and the fourth photodiode PD-A are connected in series and in reverse directions. The connection configuration between the third photodiode PD-B and the fourth photodiode PD-A is the same as that of the first detection circuit SPX1 described above, and a repeated description will be omitted.

[0069] In this embodiment, the wavelength conversion layer 81 (see FIG. 5) has a function of converting, for example, the third light (B) component of the light L1 into the first light (R) and also a function of converting the near-infrared component into the second light (G). As a result, the second organic semiconductor layer 32 of the second detection circuit SPX2 shown in FIG. 5 functions as the fourth photodiode PD-A and can detect the near-infrared component. That is, the second organic semiconductor layer 32 constituting the second photodiode PD-G and the second organic semiconductor layer 32 constituting the fourth photodiode PD-A are formed continuously in the same layer.

[0070] (Third embodiment) Fig. 7 is a circuit diagram showing one pixel and a detection circuit of a detection device 1B according to the third embodiment. As shown in Fig. 7, in the detection device 1B according to the third embodiment, the pixel PX includes a first photodiode PD-R, a second photodiode PD-G, two capacitance elements Ca1 and Ca2, a first transistor Tr1, and a second transistor Tr2.

[0071] The cathode of the first photodiode PD-R is connected to the first signal line SGL(n) via the first transistor Tr1 and to the second signal line SGL(n+1) via the second transistor Tr2. The cathode of the second photodiode PD-G is supplied with the drive signal VDDSNS from the drive signal supply circuit 123a.

[0072] In this embodiment, either the first photodiode PD-R or the second photodiode PD-G also functions as the third photodiode PD-B. For example, when the first transistor Tr1 is on and the second transistor Tr2 is off, the first photodiode PD-R detects the first light (R) and the second photodiode PD-G detects the second light (G). When the first transistor Tr1 is off and the second transistor Tr2 is on, either the first photodiode PD-R or the second photodiode PD-G detects the third light (B).

[0073] In this embodiment, the number of photodiodes PD in one pixel PX can be reduced compared to the above-described embodiment. Also, this configuration allows the use of conventional protocols as they are.

[0074] (Fourth embodiment) 8 is a cross-sectional view schematically showing a cross section of a detection device according to the fourth embodiment. As shown in FIG. 8, the detection device 1C according to the fourth embodiment further includes a light-shielding layer 82 and a reflective layer 83. The detection device 1C according to the fourth embodiment is a bottom-light-receiving optical sensor, and light L1 is incident on the second main surface S2 side of the substrate 21. In this embodiment, the light-shielding layer 82, the wavelength conversion layer 81, and the reflective layer 83 are provided on the surfaces of the first organic semiconductor layer 31 and the second organic semiconductor layer 32 opposite to the surface on which light L1 is incident (on the upper surface of the first organic semiconductor layer 31 in FIG. 8).

[0075] More specifically, the second organic semiconductor layer 32 and the first organic semiconductor layer 31 are stacked in this order on the first main surface S1 of the substrate 21. However, the stacking order of the second organic semiconductor layer 32 and the first organic semiconductor layer 31 may be reversed.

[0076] A wavelength conversion layer 81 and a reflective layer 83 are provided in this order on the upper surface of the first organic semiconductor layer 31 (the surface opposite to the incident surface of light L1). The wavelength conversion layer 81 and the reflective layer 83 are provided continuously across the first detection circuit SPX1 and the second detection circuit SPX2. The light-shielding layer 82 is provided between the first organic semiconductor layer 31 and the wavelength conversion layer 81 in a region overlapping with the first detection circuit SPX1. The light-shielding layer 82 is not provided in a region overlapping with the second detection circuit SPX2.

[0077] In other words, in the region overlapping with the first detection circuit SPX1, the second organic semiconductor layer 32 (second photodiode PD-G), the first organic semiconductor layer 31 (first photodiode PD-R), the light-shielding layer 82, the wavelength conversion layer 81, and the reflective layer 83 are stacked in this order on the first main surface S1 of the substrate 21. In the region overlapping with the second detection circuit SPX2, the second organic semiconductor layer 32 and the first organic semiconductor layer 31 (third photodiode PD-B), the wavelength conversion layer 81, and the reflective layer 83 are stacked in this order on the first main surface S1 of the substrate 21.

[0078] In the first detection circuit SPX1, the first photodiode PD-R detects the first light (R) component of the light L1, and the second photodiode PD-G detects the second light (G) component of the light L1. In the region overlapping with the first detection circuit SPX1, the light L1 that has passed through the first photodiode PD-R and the second photodiode PD-G is blocked by the light-shielding layer 82 and is prevented from traveling to the wavelength conversion layer 81.

[0079] In the second detection circuit SPX2, the component of light L1 that has passed through the second organic semiconductor layer 32 and the first organic semiconductor layer 31 (third photodiode PD-B) is incident on the wavelength conversion layer 81. Reflected light L2 that has passed through the wavelength conversion layer 81 and been reflected by the reflective layer 83 passes through the wavelength conversion layer 81 again and is incident on the second organic semiconductor layer 32 and the first organic semiconductor layer 31. As in the first embodiment, the wavelength conversion layer 81 converts the third light (B) component of light L1 into first light (R). As a result, the first organic semiconductor layer 31 of the third photodiode PD-B of the second detection circuit SPX2 outputs an output signal Vdet(B) based on the light of reflected light L2 that has been converted from third light (B) to first light (R) by the wavelength conversion layer 81.

[0080] In this embodiment, the first organic semiconductor layer 31 of the third photodiode PD-B of the second detection circuit SPX2 also detects the light L1 incident from the second main surface S2 side. For this reason, as in the first embodiment described above, the signal processing circuit 44 ( 2 (see reference) calculates the detection value of the second detection circuit SPX2 by a predetermined calculation process. That is, if the wavelength conversion layer 81 converts the third light (B) into the first light (R), for example, the detection value of the second detection circuit SPX2 can be obtained by subtracting the output value of the output signal Vdet(R) of the first organic semiconductor layer 31 of the first detection circuit SPX1 from the output value of the output signal Vdet(B) from the first organic semiconductor layer 31 (third photodiode PD-B) in the second detection circuit SPX2. If the wavelength conversion layer 81 converts the third light (B) into the second light (G), for example, the detection value of the second detection circuit SPX2 can be obtained by subtracting the output value of the output signal Vdet(G) of the second organic semiconductor layer 32 of the first detection circuit SPX1 from the output value of the output signal Vdet(G) from the second organic semiconductor layer 32 (third photodiode PD-B) in the second detection circuit SPX2, as described above. The same applies to FIGS. 9 and 11 described later, and repeated explanations will be omitted.

[0081] (Fifth embodiment) 9 is a cross-sectional view schematically illustrating a cross section of a detection device according to the fifth embodiment. As shown in FIG. 9, the detection device 1D according to the fifth embodiment is a top-light-receiving optical sensor, and light L1 is incident from the first main surface S1 side of the substrate 21. In the detection device 1D according to the fifth embodiment, a wavelength conversion layer 81, a light-shielding layer 82, a second organic semiconductor layer 32, and a first organic semiconductor layer 31 are stacked in this order on the first main surface S1 of the substrate 21.

[0082] The wavelength conversion layer 81, the second organic semiconductor layer 32, and the first organic semiconductor layer 31 are provided continuously across the first detection circuit SPX1 and the second detection circuit SPX2. The light-shielding layer 82 is provided between the first organic semiconductor layer 31 and the wavelength conversion layer 81 in a region overlapping with the first detection circuit SPX1. The light-shielding layer 82 is not provided in a region overlapping with the second detection circuit SPX2.

[0083] The reflective layer 83 is disposed opposite the second main surface S2 of the substrate 21. The reflective layer 83 is provided continuously across the first detection circuit SPX1 and the second detection circuit SPX2.

[0084] The light-shielding layer 82, the wavelength conversion layer 81, and the reflective layer 83 are disposed on the side opposite to the light L1 incident surface side of the first organic semiconductor layer 31 and the second organic semiconductor layer 32. That is, when viewed from the light L1 incident surface side, the positional relationship between the light-shielding layer 82, the wavelength conversion layer 81, and the reflective layer 83 and the first organic semiconductor layer 31 and the second organic semiconductor layer 32 is the same as in the fourth embodiment described above. The detection of light L1 and reflected light L2 by the first detection circuit SPX1 and the second detection circuit SPX2 is the same as in the fourth embodiment described above, and a repeated description will be omitted.

[0085] (Sixth embodiment) 10 is a cross-sectional view schematically illustrating a cross section of a detection device according to a sixth embodiment. As shown in FIG. 10, the detection device 1E according to the sixth embodiment is a bottom-light-receiving optical sensor, and light L1 is incident from the second main surface S2 side of the substrate 21. A wavelength conversion layer 81 and a reflective layer 83 are provided in this order on the surface of the first organic semiconductor layer 31 and the second organic semiconductor layer 32 opposite to the light incident surface (the upper surface of the first organic semiconductor layer 31). A light-shielding layer 82 is provided on the light incident surface side of the first organic semiconductor layer 31 and the second organic semiconductor layer 32 (the lower surface side of the second organic semiconductor layer 32) in a region overlapping with the second detection circuit SPX2.

[0086] More specifically, the second organic semiconductor layer 32, the first organic semiconductor layer 31, the wavelength conversion layer 81, and the reflective layer 83 are laminated in this order on the first main surface S1 of the substrate 21. The second organic semiconductor layer 32, the first organic semiconductor layer 31, the wavelength conversion layer 81, and the reflective layer 83 are provided continuously across the first detection circuit SPX1 and the second detection circuit SPX2. The light-shielding layer 82 is provided on the second main surface S2 of the substrate 21 in a region overlapping with the second detection circuit SPX2, but is not provided in a region overlapping with the first detection circuit SPX1.

[0087] As described above, the detecting device 1E is a bottom-light-receiving optical sensor, and in the second detecting circuit SPX2, the light L1 incident from the second main surface S2 side of the substrate 21 is suppressed by the light-shielding layer 82. The second detecting circuit SPX2 detects the light L1 incident obliquely on the first detecting circuit SPX1.

[0088] More specifically, in the first detection circuit SPX1, the first photodiode PD-R detects the first light (R) component of the light L1, and the second photodiode PD-G detects the second light (G) component of the light L1. The light L1 transmitted through the first photodiode PD-R (first organic semiconductor layer 31) and the second photodiode PD-G (second organic semiconductor layer 32) of the first detection circuit SPX1 is incident on the wavelength conversion layer 81. The reflected light L2 transmitted through the wavelength conversion layer 81 and reflected by the reflective layer 83 passes through the wavelength conversion layer 81 again and is incident on the second organic semiconductor layer 32 and first organic semiconductor layer 31 on the second detection circuit SPX2 side.

[0089] As in the first embodiment, the wavelength conversion layer 81 converts the third light (B) component of the light L1 into the first light (R). As a result, the first organic semiconductor layer 31 (third photodiode PD-B) of the second detection circuit SPX2 outputs an output signal Vdet(B) based on the light of the reflected light L2 that has been converted from the third light (B) to the first light (R) by the wavelength conversion layer 81.

[0090] In this embodiment, the light-shielding layer 82 is provided, which suppresses the first light (R) component of light L1 incident on the first organic semiconductor layer 31 (third photodiode PD-B) of the second detection circuit SPX2 from the second main surface S2 side. As a result, reflected light L2 that has passed through the first detection circuit SPX1 and been reflected by the reflective layer 83 is incident on the third photodiode PD-B, and the light that has been converted from third light (B) to first light (R) by the wavelength conversion layer 81 can be detected satisfactorily. Note that this embodiment does not require subtraction processing.

[0091] (Seventh embodiment) Fig. 11 is a cross-sectional view schematically showing a cross section of a detection device according to the seventh embodiment. As shown in Fig. 11, a detection device 1F according to the seventh embodiment differs from the detection device 1E according to the sixth embodiment in that the detection device 1F does not have a light-shielding layer 82. That is, the second organic semiconductor layer 32, the first organic semiconductor layer 31, the wavelength conversion layer 81, and the reflective layer 83 are stacked in this order on the first main surface S1 of the substrate 21. The light-shielding layer 82 is not provided on the second main surface S2 of the substrate 21.

[0092] The reflected light L2 reflected by the reflective layer 83 and the light L1 from the second main surface S2 side are incident on the first organic semiconductor layer 31 (third photodiode PD-B) of the second detection circuit SPX2. Even in this case, as in the first embodiment described above, the signal processing circuit 44 (FIG. 2 ) can calculate the detection value of the second detection circuit SPX2 by a predetermined calculation process.

[0093] (electronic equipment) FIG. 12 is a diagram showing an example of an electronic device to which a detection device is applied. As shown in FIG. 12, a color scanner 200 to which detection device 1 is applied has, for example, a main body 201 and a cover 202. Detection device 1 is mounted inside main body 201 and can capture an image of a detection target placed in detection area 203. Note that color scanner 200 is not limited to detection device 1, and any one of detection devices 1A-1F may be provided. Furthermore, without being limited to color scanner 200, detection device 1 and detection devices 1A-1F described above may be applied to other electronic devices such as digital cameras.

[0094] Although preferred embodiments of the present invention have been described above, the present invention is not limited to such embodiments. The contents disclosed in the embodiments are merely examples, and various modifications are possible without departing from the spirit of the present invention. Appropriate modifications made without departing from the spirit of the present invention naturally fall within the technical scope of the present invention. At least one of various omissions, substitutions, and modifications of components can be made without departing from the spirit of each of the above-described embodiments and modifications. [Explanation of symbols]

[0095] 1, 1A, 1B, 1C, 1D, 1E, 1F Detector 10 Sensor section 21 PCB 31 First organic semiconductor layer 32 Second organic semiconductor layer 40 Detector 48 Detection circuit 81 Wavelength conversion layer 82 Light blocking layer 83 Reflective layer PD photodiode PD-R 1st photodiode PD-G Second photodiode PD-B 3rd photodiode PD-A 4th photodiode SPX1 First detection circuit SPX2 Second detection circuit AA detection area GA peripheral area

Claims

1. a first detection circuit including a first photodiode sensitive to a first light and a second photodiode sensitive to a second light; a second detection circuit including a third photodiode sensitive to a third light; the first photodiode and the second photodiode are connected in series in reverse directions to form a first detection element; one end of the first detection element is connected to a first signal line via a first transistor; a first drive signal is supplied to the other end of the first detection element; a cathode of the third photodiode is connected to a second signal line via a second transistor; a second drive signal is supplied to the anode of the third photodiode; the first photodiode includes a first organic semiconductor layer sensitive to the first light; the second photodiode includes a second organic semiconductor layer sensitive to the second light; the third photodiode includes a stacked structure in which the first organic semiconductor layer and the second organic semiconductor layer are stacked, The second detection circuit includes the third photodiode and a wavelength conversion layer that converts the third light into the first light or the second light. Detection device.

2. the first organic semiconductor layer constituting the first photodiode and the first organic semiconductor layer constituting the third photodiode are formed continuously in the same layer; The second organic semiconductor layer constituting the second photodiode and the second organic semiconductor layer constituting the third photodiode are formed continuously in the same layer. The detection device according to claim 1 .

3. a reflective layer facing the wavelength conversion layer; a light-shielding layer; the wavelength conversion layer and the reflective layer are provided in this order on the surfaces of the first organic semiconductor layer and the second organic semiconductor layer opposite to the light incident surface, The light-shielding layer is provided between the first organic semiconductor layer and the second organic semiconductor layer and the wavelength conversion layer in a region overlapping with the first detection circuit. The detection device according to claim 1 .

4. a reflective layer facing the wavelength conversion layer; a light-shielding layer; the wavelength conversion layer and the reflective layer are provided in this order on the surfaces of the first organic semiconductor layer and the second organic semiconductor layer opposite to the light incident surface, The light-shielding layer is provided on the light incident surface side of the first organic semiconductor layer and the second organic semiconductor layer in a region overlapping with the second detection circuit. The detection device according to claim 1 .

5. a signal processing circuit that receives and processes output signals from the first detection circuit and the second detection circuit; The signal processing circuit calculates the detection value of the second detection circuit by subtracting the output value of the output signal of the first detection circuit from the output value of the output signal of the second detection circuit. The detection device according to claim 1 .

6. the first light is red light, the second light is green light, The third light is blue light. The detection device according to claim 1 .

7. A first detection circuit including a first photodiode sensitive to a first light and a second photodiode sensitive to a second light; a second detection circuit including a third photodiode sensitive to a third light; the first photodiode and the second photodiode are connected in series in reverse directions to form a first detection element; one end of the first detection element is connected to a first signal line via a first transistor; a first drive signal is supplied to the other end of the first detection element; a cathode of the third photodiode is connected to a second signal line via a second transistor; a second drive signal is supplied to the anode of the third photodiode; a signal processing circuit that receives and processes output signals from the first detection circuit and the second detection circuit; The signal processing circuit calculates the detection value of the second detection circuit by subtracting the output value of the output signal of the first detection circuit from the output value of the output signal of the second detection circuit. Detection device.

8. A first detection circuit including a first photodiode sensitive to a first light and a second photodiode sensitive to a second light; a second detection circuit including a third photodiode sensitive to a third light; the first photodiode and the second photodiode are connected in series in reverse directions to form a first detection element; one end of the first detection element is connected to a first signal line via a first transistor; a first drive signal is supplied to the other end of the first detection element; a cathode of the third photodiode is connected to a second signal line via a second transistor; a second drive signal is supplied to the anode of the third photodiode; the first light is red light, the second light is green light, The third light is blue light. Detection device.

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