Detector

Abstract

To provide a detector capable of capturing good images.SOLUTION: A detector includes a light source and an optical sensor including a plurality of photodiodes that output pixel data according to the amount of light irradiated thereto, and the optical sensor captures a first image including a plurality of pieces of first pixel data and a second image including a plurality of pieces of second pixel data and having higher sensitivity than the first image, selects second pixel data having a gradation equal to or lower than a predetermined threshold value in the second image, and selects first pixel data in an area corresponding to unselected second pixel data in the first image, and generates a composite image on the basis of the selected second pixel data and the selected first pixel data.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Patent Document 1 describes an image input device using a solid-state imaging element such as a CCD. In Patent Document 1, the imaging element reads the same image multiple times with different accumulation times. Then, the two pieces of image information are compared with a reference value Dref to select one of the two pieces of image information for each pixel, and the selected pieces of image information are synthesized. The reference value Dref is uniquely set in accordance with the output signal of the imaging element. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 5-176233 Summary of the Invention [Problem to be solved by the invention]

[0004] In actual imaging, there are differences in the type (color) of the object to be detected and the culture medium, the in-plane luminance distribution of the light irradiated from each light source to the sensor, and variations in the light receiving sensitivity of the sensor. Therefore, if the uniquely set reference value is not appropriate, it may not be possible to obtain a good composite image by combining two pieces of image information.

[0005] An object of the present invention is to provide a detection device capable of capturing a good image. [Means for solving the problem]

[0006] A detection device of one embodiment of the present invention has a light source and an optical sensor including a plurality of photodiodes that output pixel data according to the amount of light irradiated thereto, wherein the optical sensor captures a first image including a plurality of first pixel data and a second image including a plurality of second pixel data and having higher sensitivity than the first image, selects the second pixel data in the second image having a gradation below a predetermined threshold value, and selects the first pixel data in the first image in an area corresponding to unselected second pixel data, and generates a composite image based on the selected second pixel data and the selected first pixel data. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a cross-sectional view illustrating a schematic configuration of a detection device according to a first embodiment. [Diagram 2] FIG. 2 is a block diagram showing an example of the configuration of the detection device according to the first embodiment. [Diagram 3] FIG. 3 is a block diagram showing an example of the configuration of the detection control circuit according to the first embodiment. [Figure 4] FIG. 4 is a circuit diagram showing a sensor pixel. [Diagram 5] FIG. 5 is a plan view illustrating a sensor pixel according to the first embodiment. [Figure 6] FIG. 6 is a cross-sectional view taken along line VI-VI' of FIG. [Figure 7] FIG. 7 is an explanatory diagram for illustrating a method for generating a composite image using a first image with low sensitivity and a second image with high sensitivity. [Figure 8] FIG. 8 is a timing waveform diagram for explaining an example of the operation of the detection device according to the first embodiment. [Figure 9] FIG. 9 is an explanatory diagram for explaining an example of the threshold value of pixel data. [Figure 10] FIG. 10 is a flowchart showing a method for generating a composite image of the detection device according to the first embodiment. [Figure 11] FIG. 11 is a plan view illustrating a schematic configuration example of a plurality of light sources in a detection device according to the second embodiment. [Figure 12] FIG. 12 is a timing waveform diagram for explaining an example of the operation of the detection device according to the second embodiment. [Figure 13] FIG. 13 is a plan view illustrating an optical sensor and a color filter of a detection device according to a modified example of the second embodiment. [Figure 14] FIG. 14 is an explanatory diagram for explaining a luminance correction method for a composite image in the detection device according to the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The form (embodiment) for carrying out the present invention will be described in detail with reference to the drawings. The present disclosure is not limited by the contents described in the following embodiments. The components described below include those that a person skilled in the art can easily imagine and those that are substantially the same. Furthermore, the components described below can be appropriately combined. Note that the disclosure is merely an example, and those that a person skilled in the art can easily imagine appropriate modifications while maintaining the gist of the present disclosure are naturally included in the scope of the present disclosure. In addition, in order to make the explanation clearer, the drawings may be schematic in terms of the width, thickness, shape, etc. of each part compared to the actual embodiment, but they are merely examples and do not limit the interpretation of the present disclosure. In addition, in this disclosure and each figure, elements similar to those described above with respect to the previously mentioned figures may be given the same reference numerals, and detailed explanations may be omitted as appropriate.

[0009] In this specification and the claims, when expressing an aspect of arranging 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 arranged 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 arranged above a certain structure via yet another structure.

[0010] (First embodiment) Fig. 1 is a cross-sectional view showing a schematic diagram of a detection device according to a first embodiment. As shown in Fig. 1, the detection device 1 includes an optical sensor 10, an optical filter layer 50, a mounting substrate 110 for mounting a detection target 100, and a light source device 80. The optical filter layer 50, the mounting substrate 110 (detection target 100 and culture medium 102), and the light source device 80 are arranged in this order on the optical sensor 10.

[0011] The object to be detected 100 is a minute object such as bacteria. The detection device 1 is a biosensor that detects minute objects such as bacteria. The mounting substrate 110 is a light-transmitting container made of, for example, glass. The mounting substrate 110 includes a container body 111 and a cover member 112. The mounting substrate 110 is, for example, a petri dish. The plurality of object to be detected 100 are mounted on the container body 111 of the mounting substrate 110 together with the culture medium 102. In addition, a cover member 112 that covers the plurality of object to be detected 100 is provided on the upper side of the container body 111. The object to be detected 100 is mounted in the mounting substrate 110 and disposed between the optical sensor 10 and the light source device 80.

[0012] The detection object 100 is not limited to bacteria, but may be other minute objects such as cells. The detection device 1 is not limited to a biosensor, but may be configured as, for example, a fingerprint detection device that detects fingerprints, or a vein detection device that detects blood vessel patterns such as veins. In this case, the detection object 100 may be a living body such as a finger, a palm, or a wrist.

[0013] The optical sensor 10 is a planar detection device including a plurality of photodiodes 30 (photodetection elements) arranged in a planar shape. A detailed configuration of the optical sensor 10 will be described later with reference to FIGS.

[0014] The optical filter layer 50 is an optical directivity control element disposed between a plurality of light sources 82 (light source device 80) and a plurality of photodiodes 30 (optical sensor 10). More specifically, the optical filter layer 50 is provided between a plurality of photodiodes 30 of the optical sensor 10 and a mounting substrate 110. The optical filter layer 50 is disposed facing the plurality of photodiodes 30 of the optical sensor 10. The optical filter layer 50 is an optical element that transmits a component of the light L irradiated from the light source 82, the component traveling in a direction perpendicular to the optical sensor 10, toward the photodiode 30. The optical filter layer 50 is also called a collimator aperture or a collimator.

[0015] The light source device 80 includes a light source substrate 81 and a plurality of light sources 82. The plurality of light sources 82 are point light sources provided corresponding to the plurality of photodiodes 30 of the optical sensor 10. The plurality of light sources 82 are provided on the light source substrate 81 and disposed opposite the plurality of photodiodes 30 of the optical sensor 10. Each of the plurality of light sources 82 is formed of, for example, a light emitting diode (LED: Light Emitting Diode).

[0016] Light L emitted from the light source 82 passes through the mounting substrate 110 (container body 111 and cover member 112), the culture medium 102, and the optical filter layer 50, and is irradiated toward the multiple photodiodes 30 of the optical sensor 10. The amount of light irradiated to the multiple photodiodes 30 differs between an area overlapping with the object to be detected 100 and an area not overlapping with the object to be detected 100. This allows the optical sensor 10 to capture an image of the object to be detected 100.

[0017] In this embodiment, a plurality of light sources 82 are arranged at a predetermined pitch as point light sources. Therefore, the variation of the light L is suppressed compared to the case where a surface light source is provided, and good imaging can be achieved. The arrangement pitch of the plurality of light sources 82 is set so as to suppress interference of the light L irradiated from adjacent light sources 82. Furthermore, the light L whose viewing angle is limited by the optical filter layer 50 is irradiated onto the optical sensor 10, and the arrangement pitches PS1, PS2 of the plurality of photodiodes 30 are set so as to ensure a light receiving area at the optical sensor 10.

[0018] 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 host IC 70 that controls the optical sensor 10 and a light source device 80. The optical sensor 10 includes an array substrate 2, a plurality of sensor pixels 3 (photodiodes 30) formed on the array substrate 2, gate line driving circuits 15A and 15B, a signal line driving circuit 16A, and a detection control circuit 11.

[0019] The array substrate 2 is formed using a substrate 21 as a base. Each of the sensor pixels 3 includes a photodiode 30, a plurality of transistors, and various wirings. The array substrate 2 on which the photodiodes 30 are formed is a drive circuit substrate that drives a sensor for each predetermined detection region, and is also called a backplane or active matrix substrate.

[0020] The substrate 21 has a detection area AA and a peripheral area GA. The detection area AA is an area in which a plurality of sensor pixels 3 (a plurality of photodiodes 30) 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, and is an area in which the plurality of sensor pixels 3 are not provided. The gate line driving circuits 15A and 15B, the signal line driving circuit 16A, and the detection control circuit 11 are provided in the peripheral area GA.

[0021] Each of the sensor pixels 3 is an optical sensor having a photodiode 30 as a sensor element. The photodiode 30 outputs an electrical signal according to the light irradiated thereon. More specifically, the photodiode 30 is a PIN (Positive Intrinsic Negative) photodiode or an OPD (Organic Photodiode) using an organic semiconductor. The sensor pixels 3 (the photodiodes 30) are arranged in a matrix in the detection area AA.

[0022] The detection control circuit 11 is a circuit that supplies control signals Sa, Sb, and Sc to the gate line driving circuits 15A, 15B and the signal line driving circuit 16A, respectively, and controls their operations. Specifically, the gate line driving circuits 15A, 15B output gate driving signals to the gate lines GLS (see FIG. 4) based on the control signals Sa and Sb. The signal line driving circuit 16A electrically connects the signal line SLS selected based on the control signal Sc to the detection control circuit 11. In addition, the detection control circuit 11 includes a signal processing circuit that processes the detection signals Vdet from the multiple photodiodes 30.

[0023] The photodiodes 30 of the multiple sensor pixels 3 perform detection in accordance with gate drive signals supplied from the gate line drive circuits 15A and 15B. The multiple photodiodes 30 output electrical signals corresponding to the light irradiated thereon as detection signals Vdet to the signal line drive circuit 16A. The detection control circuit 11 (detection circuit) is electrically connected to the multiple photodiodes 30. The detection control circuit 11 processes the detection signals Vdet from the multiple photodiodes 30, and outputs pixel data Cap based on the detection signals Vdet to the host IC 70. The pixel data Cap is a sensor value acquired for each sensor pixel 3. In this way, the detection device 1 detects information related to the object to be detected 100.

[0024] Fig. 3 is a block diagram showing an example of the configuration of the detection control circuit according to the first embodiment. As shown in Fig. 3, the detection control circuit 11 has a detection signal amplitude adjustment circuit 41, an A / D conversion circuit 42, a signal processing circuit 43, and a detection timing control circuit 44. In the detection control circuit 11, the detection timing control circuit 44 controls the detection signal amplitude adjustment circuit 41, the A / D conversion circuit 42, and the signal processing circuit 43 to operate in synchronization with each other based on a control signal supplied from a host IC 70 (see Fig. 2).

[0025] The detection signal amplitude adjustment circuit 41 is a circuit that adjusts the amplitude of the detection signal Vdet output from the photodiode 30, and is configured to include, for example, an amplifier. The A / D conversion circuit 42 converts the analog signal output from the detection signal amplitude adjustment circuit 41 into a digital signal. The signal processing circuit 43 is a circuit that processes the digital signal from the A / D conversion circuit 42 and transmits pixel data Cap to the host IC 70.

[0026] 2, the light source device 80 has a light source substrate 81, a plurality of light sources 82 formed on the light source substrate 81, and a light source control circuit 12. The plurality of light sources 82 are arranged in a matrix in an area overlapping with the detection area AA of the light source substrate 81. The light source substrate 81 is switched on (lighted state) and off (non-lighted state) based on a control signal from the light source control circuit 12.

[0027] The light source control circuit 12 turns on the multiple light sources 82 with different light intensities for each of the detection periods T1 and T2 (see FIG. 8). Furthermore, the light source device 80 may switch each of the multiple light sources 82 between being lit (on) and not being lit (off).

[0028] Any method may be used for controlling the on / off of the multiple light sources 82. For example, the light source control circuit 12 may individually control each of the multiple light sources 82. Furthermore, the light source substrate 81 of the light source device 80 may be a so-called active matrix substrate.

[0029] The host IC 70 controls the optical sensor 10 and the light source device 80 to capture a first image IM1 with low sensitivity including a plurality of first pixel data Cap1 and a second image IM2 with higher sensitivity than the first image IM1 including a plurality of second pixel data Cap2. The host IC 70 then generates a composite image IM-C based on the second pixel data Cap2 selected in the second image IM2 and the first pixel data Cap1 selected in the first image IM1. The detection device 1 of this embodiment can also be said to be an image generating device that generates the composite image IM-C. Details of the method of generating the composite image IM-C will be described later with reference to FIG. 7 and subsequent figures.

[0030] The host IC 70 has a pixel data storage circuit 71, an arithmetic circuit 72, and a threshold value storage circuit 73 as control circuits on the optical sensor 10 side. The pixel data storage circuit 71 stores pixel data Cap (first pixel data Cap1 and second pixel data Cap2) output from the detection control circuit 11 of the optical sensor 10. The arithmetic circuit 72 performs a predetermined arithmetic process on the pixel data Cap of the photodiode 30. For example, the arithmetic circuit 72 compares the first image IM1 and the second image IM2 with a predetermined threshold value and selects the first pixel data Cap1 and the second pixel data Cap2, respectively.

[0031] The threshold memory circuit 73 is a circuit that stores a first threshold value ARU and a second threshold value ARL (see FIG. 10) for selecting the second pixel data Cap2 in the second image IM2. Although the pixel data memory circuit 71 and the threshold memory circuit 73 are described as separate circuits, they may be formed as one memory circuit. Furthermore, the pixel data memory circuit 71 and the threshold memory circuit 73 are not limited to storing the pixel data Cap and each threshold value, and may store various other information.

[0032] The host IC 70 has a lighting control circuit 74 and a lighting pattern storage circuit 75 as control circuits on the light source device 80 side. The lighting pattern storage circuit 75 stores the light intensities of the multiple light sources 82, or, as necessary, the arrangement pattern of the multiple light sources 82 in an on (lighted) or off (non-lighted) state. The lighting control circuit 74 outputs a control signal Sd to the light source control circuit 12 based on various information from the lighting pattern storage circuit 75 (for example, information on the light intensities of the multiple light sources 82).

[0033] The host IC 70 further includes an image generation circuit 76. The image generation circuit 76 combines the first pixel data Cap1 and the second pixel data Cap2 selected by the arithmetic circuit 72 to generate a composite image IM-C.

[0034] Although not shown, the host IC 70 has a control circuit that synchronously controls the detection control circuit 11 and the light source control circuit 12. That is, based on a control signal from the host IC 70, switching of the light amounts of the multiple light sources 82 on the light source device 80 side and detection of the multiple photodiodes 30 on the optical sensor 10 side are synchronously controlled.

[0035] Although the optical sensor 10 has two gate line driving circuits 15A and 15B, it may have one gate line driving circuit. The light source device 80 has a light source control circuit 12, but the light source control circuit 12 may be provided as a common circuit with the lighting control circuit 74 of the host IC 70.

[0036] Next, a configuration example of the optical sensor 10 will be described. FIG. 4 is a circuit diagram showing a sensor pixel. As shown in FIG. 4, the sensor pixel 3 includes a photodiode 30, a capacitance element Ca, and a transistor TrS. The transistor TrS is provided corresponding to the photodiode 30. The transistor TrS is configured by a thin film transistor, and in this example, is configured by an n-channel MOS (Metal Oxide Semiconductor) type TFT (Thin Film Transistor). The gate of the transistor TrS is connected to a gate line GLS. The source of the transistor TrS is connected to a signal line SLS. The drain of the transistor TrS is connected to the anode of the photodiode 30 and the capacitance element Ca.

[0037] A power supply potential SVS is supplied to the cathode of the photodiode 30 from the detection control circuit 11. In addition, a reference potential VR1, which is the initial potential of the capacitance element Ca, is supplied from the detection control circuit 11 to the capacitance element Ca.

[0038] When light is irradiated onto the sensor pixel 3, a current corresponding to the amount of light flows through the photodiode 30, and thus a charge is accumulated in the capacitance element Ca. When the transistor TrS is turned on, a current flows through the signal line SLS according to the charge accumulated in the capacitance element Ca. The signal line SLS is connected to the detection control circuit 11 via the signal line driving circuit 16A. This allows the optical sensor 10 of the detection device 1 to detect a signal corresponding to the amount of light irradiated onto the photodiode 30 for each sensor pixel 3.

[0039] The transistor TrS is not limited to an n-type TFT, and may be a p-type TFT. The pixel circuit of the sensor pixel 3 shown in FIG. 4 is merely an example, and the sensor pixel 3 may include multiple transistors corresponding to one photodiode 30.

[0040] Next, a detailed configuration of the optical sensor 10 will be described. Fig. 5 is a plan view showing a schematic view of a sensor pixel according to the first embodiment.

[0041] In the following description, the first direction Dx is a direction in a plane parallel to the substrate 21 (see FIG. 6). 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. The third direction Dz is a direction perpendicular to the first direction Dx and the second direction Dy, and is a normal direction to the main surface of the substrate 21. In addition, "planar view" refers to the positional relationship when viewed from a direction perpendicular to the substrate 21.

[0042] As shown in FIG. 5, the sensor pixel 3 is an area surrounded by the gate line GLS and the signal line SLS. In this embodiment, the gate line GLS includes a first gate line GLA and a second gate line GLB. The first gate line GLA is provided so as to overlap with the second gate line GLB. The first gate line GLA and the second gate line GLB are provided in different layers via insulating layers 22c and 22d (see FIG. 6). The first gate line GLA and the second gate line GLB are electrically connected at an arbitrary point, and a gate driving signal having the same potential is supplied. At least one of the first gate line GLA and the second gate line GLB is connected to the gate line driving circuits 15A and 15B. In FIG. 5, the first gate line GLA and the second gate line GLB have different widths, but may have the same width.

[0043] The photodiodes 30 are provided in an area surrounded by the gate lines GLS and the signal lines SLS. An upper electrode 34 and a lower electrode 35 are provided corresponding to each of the photodiodes 30. The photodiodes 30 are, for example, PIN photodiodes. The lower electrode 35 is, for example, an anode electrode of the photodiode 30. The upper electrode 34 is, for example, a cathode electrode of the photodiode 30.

[0044] The upper electrode 34 is connected to the power signal line Lvs via the connection wiring 36. The power signal line Lvs is a wiring that supplies the power potential SVS to the photodiode 30. In this embodiment, the power signal line Lvs overlaps with the signal line SLS and extends in the second direction Dy. The sensor pixels 3 arranged in the second direction Dy are connected to a common power signal line Lvs. With this configuration, the opening of the sensor pixel 3 can be made larger. The lower electrode 35, the photodiode 30, and the upper electrode 34 are substantially rectangular in plan view. However, this is not limited thereto, and the shapes of the lower electrode 35, the photodiode 30, and the upper electrode 34 can be changed as appropriate.

[0045] The transistor TrS is provided near the intersection of the gate line GLS and the signal line SLS, and includes a semiconductor layer 61, a source electrode 62, a drain electrode 63, a first gate electrode 64A, and a second gate electrode 64B.

[0046] The semiconductor layer 61 is an oxide semiconductor. More preferably, the semiconductor layer 61 is a transparent amorphous oxide semiconductor (TAOS) among oxide semiconductors. By using an oxide semiconductor for the transistor TrS, the leakage current of the transistor TrS can be suppressed. That is, the transistor TrS can reduce the leakage current from the non-selected sensor pixels 3. Therefore, the optical sensor 10 can improve the S / N ratio. However, the semiconductor layer 61 is not limited thereto, and may be a microcrystalline oxide semiconductor, an amorphous oxide semiconductor, polysilicon, low temperature polycrystalline silicon (LTPS), or the like.

[0047] The semiconductor layer 61 is provided along the first direction Dx and intersects with the first gate electrode 64A and the second gate electrode 64B in a plan view. The first gate electrode 64A and the second gate electrode 64B are provided branching off from the first gate line GLA and the second gate line GLB, respectively. In other words, the portions of the first gate line GLA and the second gate line GLB that overlap with the semiconductor layer 61 function as the first gate electrode 64A and the second gate electrode 64B. The first gate electrode 64A and the second gate electrode 64B are made of aluminum (Al), copper (Cu), silver (Ag), molybdenum (Mo), or an alloy thereof. In addition, a channel region is formed in the portion of the semiconductor layer 61 that overlaps with the first gate electrode 64A and the second gate electrode 64B.

[0048] One end of the semiconductor layer 61 is connected to a source electrode 62 via a contact hole H1. The other end of the semiconductor layer 61 is connected to a drain electrode 63 via a contact hole H2. A portion of the signal line SLS that overlaps with the semiconductor layer 61 serves as a source electrode 62. A portion of the third conductive layer 67 that overlaps with the semiconductor layer 61 functions as a drain electrode 63. The third conductive layer 67 is connected to the lower electrode 35 via a contact hole H3. With this configuration, the transistor TrS can switch between connection and disconnection between the photodiode 30 and the signal line SLS.

[0049] Next, a description will be given of the layer structure of the optical sensor 10. Fig. 6 is a cross-sectional view taken along line VI-VI' in Fig. 5.

[0050] In the description of the detection device 1 including the optical sensor 10, in a direction perpendicular to the surface of the substrate 21 (third direction Dz), the direction from the substrate 21 toward the photodiode 30 is referred to as the "upper side" or "top". The direction from the photodiode 30 toward the substrate 21 is referred to as the "lower side" or "bottom".

[0051] 6, the substrate 21 is an insulating substrate, and for example, a glass substrate such as quartz or non-alkali glass is used. On one surface of the substrate 21, a transistor TrS, various wirings (gate lines GLS and signal lines SLS), and an insulating layer are provided to form an array substrate 2. A plurality of photodiodes 30 are arranged on the array substrate 2, that is, on one surface side of the substrate 21. The substrate 21 may be a resin substrate or a resin film made of a resin such as polyimide.

[0052] The insulating layers 22a and 22b are provided on the substrate 21. The insulating layers 22a, 22b, 22c, 22d, 22e, 22f, and 22g are inorganic insulating films, such as silicon oxide (SiO2), silicon nitride (SiN), etc. Furthermore, each inorganic insulating layer is not limited to a single layer and may be a laminated film.

[0053] The first gate electrode 64A is provided on the insulating layer 22b. The insulating layer 22c is provided on the insulating layer 22b, covering the first gate electrode 64A. The semiconductor layer 61, the first conductive layer 65, and the second conductive layer 66 are provided on the insulating layer 22c. The first conductive layer 65 is provided to cover an end of the semiconductor layer 61 that is connected to the source electrode 62. The second conductive layer 66 is provided to cover an end of the semiconductor layer 61 that is connected to the drain electrode 63.

[0054] The insulating layer 22d is provided on the insulating layer 22c, covering the semiconductor layer 61, the first conductive layer 65, and the second conductive layer 66. The second gate electrode 64B is provided on the insulating layer 22d. The semiconductor layer 61 is provided between the first gate electrode 64A and the second gate electrode 64B in a direction perpendicular to the substrate 21. That is, the transistor TrS has a so-called dual gate structure. However, the transistor TrS may have a bottom gate structure in which the first gate electrode 64A is provided and the second gate electrode 64B is not provided, or may have a top gate structure in which the first gate electrode 64A is not provided and only the second gate electrode 64B is provided.

[0055] The insulating layer 22e is provided on the insulating layer 22d, covering the second gate electrode 64B. The source electrode 62 (signal line SLS) and the drain electrode 63 (third conductive layer 67) are provided on the insulating layer 22e. In this embodiment, the drain electrode 63 is the third conductive layer 67 provided on the semiconductor layer 61 via the insulating layers 22d and 22e. The source electrode 62 is electrically connected to the semiconductor layer 61 via a contact hole H1 and a first conductive layer 65. The drain electrode 63 is electrically connected to the semiconductor layer 61 via a contact hole H2 and a second conductive layer 66.

[0056] The third conductive layer 67 is provided in a region overlapping with the photodiode 30 in a plan view. The third conductive layer 67 is also provided above the semiconductor layer 61, the first gate electrode 64A, and the second gate electrode 64B. That is, the third conductive layer 67 is provided between the second gate electrode 64B and the lower electrode 35 in a direction perpendicular to the substrate 21. Thus, the third conductive layer 67 functions as a protective layer that protects the transistor TrS.

[0057] The second conductive layer 66 extends opposite to the third conductive layer 67 in a region not overlapping with the semiconductor layer 61. A fourth conductive layer 68 is provided on the insulating layer 22d in a region not overlapping with the semiconductor layer 61. The fourth conductive layer 68 is provided between the second conductive layer 66 and the third conductive layer 67. As a result, a capacitance is formed between the second conductive layer 66 and the fourth conductive layer 68, and a capacitance is formed between the third conductive layer 67 and the fourth conductive layer 68. The capacitance formed by the second conductive layer 66, the third conductive layer 67, and the fourth conductive layer 68 is the capacitance of the capacitive element Ca shown in FIG. 4.

[0058] The first organic insulating layer 23a is provided on the insulating layer 22e, covering the source electrode 62 (signal line SLS) and the drain electrode 63 (third conductive layer 67). The first organic insulating layer 23a is a planarizing layer that planarizes irregularities formed by the transistor TrS and various conductive layers.

[0059] Next, a description will be given of a cross-sectional configuration of the photodiode 30. The photodiode 30 is formed by stacking a lower electrode 35, the photodiode 30, and an upper electrode 34 in this order on the first organic insulating layer 23a of the array substrate 2.

[0060] The lower electrode 35 is provided on the first organic insulating layer 23a and is electrically connected to the third conductive layer 67 through a contact hole H3. The lower electrode 35 is an anode of the photodiode 30 and is an electrode for reading out the detection signal Vdet. For example, the lower electrode 35 is made of a metal material such as molybdenum (Mo) or aluminum (Al). Alternatively, the lower electrode 35 may be a laminated film in which a plurality of these metal materials are laminated. The lower electrode 35 may be made of a conductive material having light transmission properties such as ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide).

[0061] The photodiode 30 includes an i-type semiconductor layer 31, an n-type semiconductor layer 32, and a p-type semiconductor layer 33 as semiconductor layers. The i-type semiconductor layer 31, the n-type semiconductor layer 32, and the p-type semiconductor layer 33 are formed of, for example, amorphous silicon (a-Si). In FIG. 6, the p-type semiconductor layer 33, the i-type semiconductor layer 31, and the n-type semiconductor layer 32 are stacked in this order in the direction perpendicular to the surface of the substrate 21. However, the opposite configuration, that is, the n-type semiconductor layer 32, the i-type semiconductor layer 31, and the p-type semiconductor layer 33 may also be used. Each semiconductor layer may be a photoelectric conversion element made of an organic semiconductor.

[0062] The n-type semiconductor layer 32 is an n+ region formed by doping impurities into a-Si. The p-type semiconductor layer 33 is a p+ region formed by doping impurities into a-Si. The i-type semiconductor layer 31 is, for example, a non-doped intrinsic semiconductor, and has lower conductivity than the n-type semiconductor layer 32 and the p-type semiconductor layer 33.

[0063] The upper electrode 34 is a cathode of the photodiode 30, and is an electrode for supplying a power supply potential SVS to the photoelectric conversion layer. The upper electrode 34 is a light-transmitting conductive layer such as ITO, and a plurality of upper electrodes are provided for each photodiode 30.

[0064] An insulating layer 22f and an insulating layer 22g are provided on the first organic insulating layer 23a. The insulating layer 22f covers the periphery of the upper electrode 34, and an opening is provided at a position where the insulating layer 22f overlaps with the upper electrode 34. The connection wiring 36 is connected to the upper electrode 34 at a portion of the upper electrode 34 where the insulating layer 22f is not provided. The insulating layer 22g is provided on the insulating layer 22f, covering the upper electrode 34 and the connection wiring 36. A second organic insulating layer 23b, which is a planarizing layer, is provided on the insulating layer 22g. In the case of an organic semiconductor photodiode 30, an insulating layer 22h may be further provided thereon.

[0065] Next, an example of a detection method of the detection device 1 of this embodiment will be described. Fig. 7 is an explanatory diagram for typically explaining a method of generating a composite image using a first image with low sensitivity and a second image with high sensitivity. Fig. 8 is a timing waveform diagram for explaining an example of the operation of the detection device according to the first embodiment. Fig. 9 is an explanatory diagram for explaining an example of a threshold value of pixel data.

[0066] As shown in Fig. 7, the optical sensor 10 captures a first image IM1 with low sensitivity and a second image IM2 with higher sensitivity than the first image IM1. For ease of understanding, Fig. 7 illustrates a case where the first image IM1 and the second image IM2 are respectively captured of three objects to be detected 100A, 100B, and 100C and a culture medium 102. In the following description, when it is not necessary to distinguish between the objects to be detected 100A, 100B, and 100C, they will simply be referred to as the object to be detected 100.

[0067] The detection device 1 captures images of the same object to be detected 100 and culture medium 102 with different light intensities of the light source 82, and obtains a first image IM1 and a second image IM2 with different sensitivities. Specifically, as shown in FIG. 8, the detection device 1 has a detection period T1 for acquiring the first image IM1 and a detection period T2 for acquiring the second image IM2. In the example shown in FIG. 8, the detection period T1 is divided into a plurality of detection periods T1-1, T1-2, and T1-3, and the light source 82 is turned on in a time-division manner for each of the detection periods T1-1, T1-2, and T1-3. Similarly, the detection period T2 is divided into a plurality of detection periods T2-1, T2-2, and T2-3, and the light source 82 is turned on in a time-division manner for each of the detection periods T2-1, T2-2, and T2-3.

[0068] The light source 82 emits a first amount of light during the detection period T1. The optical sensor 10 scans the multiple photodiodes 30 and detects the detection target 100 and the medium 102 based on the first amount of light.

[0069] Specifically, the gate line driving circuits 15A and 15B of the optical sensor 10 sequentially scan the gate lines GLS-1 in the first row to the gate line GLS-m in the last row based on a control signal from the host IC 70. As a result, the optical sensor 10 scans the entire surface of the multiple photodiodes 30 in the detection area AA. The multiple photodiodes 30 output a detection signal Vdet corresponding to the first amount of light irradiated from the light source 82. The detection control circuit 11 performs signal processing on the detection signal Vdet from the multiple photodiodes 30 and outputs first pixel data Cap1. As a result, the detection device 1 captures a low-sensitivity first image IM1 including the first pixel data Cap1 in the detection period T1.

[0070] The light source 82 emits light of a second amount of light greater than the first amount of light during the detection period T2. The optical sensor 10 scans the multiple photodiodes 30 and detects the detection target 100 and the culture medium 102 based on the second amount of light.

[0071] Specifically, similarly to the detection period T1, the optical sensor 10 scans the entire surface of the multiple photodiodes 30 in the detection area AA. The multiple photodiodes 30 output a detection signal Vdet corresponding to the second amount of light irradiated from the light source 82. The detection control circuit 11 performs signal processing on the detection signal Vdet from the multiple photodiodes 30 and outputs second pixel data Cap2. As a result, the detection device 1 captures a second image IM2 including the second pixel data Cap2 and having higher sensitivity than the first image IM1 during the detection period T2.

[0072] In this embodiment, the second amount of light emitted by the light source 82 in the detection period T2 has a higher luminance than the first amount of light in the detection period T1. However, without being limited thereto, the second amount of light has at least one of a luminance of the light source 82 and an irradiation time greater than the first amount of light. Specifically, the second amount of light may have a longer irradiation time and a longer exposure time of the photodiode 30 than the first amount of light. Alternatively, the second amount of light may have a higher luminance, a longer irradiation time, and a longer exposure time of the photodiode 30 than the first amount of light.

[0073] Also, the timing waveform diagram shown in FIG. 8 is merely a schematic diagram and can be modified as appropriate. For example, the detection device 1 may perform detection at least once (one frame) in each of the detection periods T1 and T2. Also, in FIG. 8, the first image IM1 with low sensitivity is captured in the detection period T1, and then the second image IM2 with high sensitivity is captured in the detection period T2, but the first image IM1 and the second image IM2 may be captured in any order. For example, the second image IM2 with high sensitivity may be captured in the detection period T1, and then the first image IM1 with low sensitivity may be captured in the detection period T1, or they may be captured alternately in a time-division manner.

[0074] 7, the first image IM1 includes a plurality of first pixel data Cap1-1, Cap1-2, Cap1-3, and Cap1-4. The first pixel data Cap1-1, Cap1-2, Cap1-3, and Cap1-4 are detected based on a first amount of light and correspond to the culture medium 102 and the detection objects 100A, 100B, and 100C, respectively. The first pixel data Cap1-1, Cap1-2, Cap1-3, and Cap1-4 each have a different gradation.

[0075] The second image IM2 includes a plurality of second pixel data Cap2-1, Cap2-2, Cap2-3, and Cap2-4. The second pixel data Cap2-1, Cap2-2, Cap2-3, and Cap2-4 are detected based on the second amount of light and correspond to the culture medium 102 and the detection objects 100A, 100B, and 100C, respectively. The gradations of the second pixel data Cap2-1, Cap2-2, Cap2-3, and Cap2-4 are different from the gradations of the first pixel data Cap1-1, Cap1-2, Cap1-3, and Cap1-4 of the first image IM1. More specifically, the gradations of the second pixel data Cap2-1, Cap2-2, Cap2-3, and Cap2-4 are greater than the gradations of the first pixel data Cap1-1, Cap1-2, Cap1-3, and Cap1-4 of the first image IM1.

[0076] In the low-sensitivity first image IM1, in the low gradation (black display) portion (for example, the first pixel data Cap1-4 corresponding to the detection object 100C), the detection intensity of the photodiode 30 is low and noise may occur. On the other hand, in the high-sensitivity second image IM2, in the high gradation (white display) portion (for example, the second pixel data Cap2-1, Cap2-2 corresponding to the medium 102 and the detection object 100A), the detection intensity of the photodiode 30 may be saturated and the detection object 100A may not be detected.

[0077] The detection device 1 of this embodiment performs image analysis on the first image IM1 and the second image IM2, and calculates a conversion coefficient RCnv used to combine the first image IM1 and the second image IM2. In the image analysis, the arithmetic circuit 72 selects the second pixel data Cap2 in the second image IM2 that is equal to or greater than the second threshold value ARL and equal to or less than the first threshold value ARU as an analysis target. In other words, the arithmetic circuit 72 selects the second pixel data Cap2 that corresponds to an area in which no noise occurs in the low-sensitivity first image IM1 and an area in which the detection intensity of the photodiode 30 is not saturated in the high-sensitivity second image IM2.

[0078] 7, the regions in the first low-sensitivity image IM1 where noise does not occur are the regions corresponding to the culture medium 102 and the objects to be detected 100A and 100B. The regions in the second high-sensitivity image IM2 where the detection intensity of the photodiode 30 is not saturated are the regions corresponding to the objects to be detected 100B and 100C.

[0079] The arithmetic circuit 72 selects the second pixel data Cap2-3 corresponding to the object 100B in the second image IM2 as an analysis target, as an area where noise does not occur in the low-sensitivity first image IM1 and an area where the detection intensity of the photodiode 30 does not saturate in the high-sensitivity second image IM2. In other words, the arithmetic circuit 72 does not select an area corresponding to the object 100C where noise occurs in the low-sensitivity first image IM1, that is, the second pixel data Cap2-4 in the second image IM2. In addition, the arithmetic circuit 72 does not select the second pixel data Cap2-1 and Cap2-2 corresponding to the medium 102 and the object 100A where the detection intensity of the photodiode 30 saturates in the high-sensitivity second image IM2.

[0080] The arithmetic circuit 72 calculates the gradation ratio R between the second pixel data Cap2-3 and the first pixel data Cap1-3 for each sensor pixel 3 in the region corresponding to the object 100B to be analyzed. The gradation ratio R is calculated as R=Cap1 / Cap2. The arithmetic circuit 72 then calculates the average value of the gradation ratios R of each sensor pixel 3 as a conversion coefficient RCnv.

[0081] Next, the arithmetic circuit 72 uses the conversion coefficient RCnv to synthesize the first image IM1 and the second image IM2 to generate a synthetic image IM-C. Specifically, the arithmetic circuit 72 selects the second pixel data Cap2-3 and Cap2-4 (areas corresponding to the objects 100B and 100C) having a gradation equal to or lower than a predetermined first threshold value ARU in the second image IM2. The second pixel data Cap2-1 and Cap2-2 (areas corresponding to the medium 102 and the object 100A) having a gradation higher than the first threshold value ARU are not selected.

[0082] The arithmetic circuit 72 multiplies the second pixel data Cap2-3, Cap2-4 selected in the second image IM2 by the conversion coefficient RCnv to calculate composite pixel data Comp(3), Comp(4).

[0083] In addition, the arithmetic circuit 72 selects the first pixel data Cap1-1, Cap1-2 in the first image IM1 as the composite pixel data Comp(1), Comp(2) of the areas corresponding to the unselected second pixel data Cap2-1, Cap2-2 (the culture medium 102 and the detection object 100A).

[0084] The image generation circuit 76 (see FIG. 2) generates a composite image IM-C based on the composite pixel data Comp(3), Comp(4) and the composite pixel data Comp(1), Comp(2). In other words, the image generation circuit 76 generates a composite image IM-C based on the second pixel data Cap2-3, Cap2-4 selected in the second image IM2 and the first pixel data Cap1-1, Cap1-2 selected in the first image IM1.

[0085] Here, the first threshold value ARU and the second threshold value ARL are set, for example, by the method shown in FIG. 9. The left diagram of FIG. 9 is a schematic diagram in which the gradations (theoretical values) of the detection object 100 (including the culture medium 102) are arranged in order from a low gradation Gd(0) to a high gradation Gd(255) for each sensor pixel 3. The first image IM1 and the second image IM2 shown in the right diagram of FIG. 9 show the gradations of pixel data Cap captured by varying the amount of light from the light source 82 in an arrangement corresponding to the theoretical values ​​of the sensor pixels 3 shown in the left diagram of FIG. 9. The first pixel data Cap1 of the first image IM1 is shifted to the low gradation side compared to the theoretical value. The second pixel data Cap2 of the second image IM2 is shifted to the high gradation side compared to the theoretical value.

[0086] In the first image IM1, the first pixel data Cap1-a on the low gradation side is an area where noise occurs. No noise occurs in the first pixel data Cap1-b on the high gradation side. In the array of the sensor pixels 3 in FIG. 9, the sensor pixel 3-a is the sensor pixel 3 located on the rightmost side among the sensor pixels 3 where noise occurs. In other words, noise does not occur in the sensor pixels 3 to the right of the sensor pixel 3-a.

[0087] In the second image IM2, the gray level obtained by adding a margin of several gray levels to the gray level corresponding to the rightmost sensor pixel 3-a in the area where noise occurs is set as the second threshold value ARL.

[0088] In the second image IM2, in the second pixel data Cap2-a on the low gradation side, the detection intensity of the photodiode 30 does not saturate, and the gradation of the second pixel data Cap2 can be detected well. In the second pixel data Cap2-b on the high gradation side, the detection intensity of the photodiode 30 saturates, and the gradation of the second pixel data Cap2 cannot be detected (all white is displayed). In the array of the sensor pixels 3 in FIG. 9, the sensor pixel 3-b is the leftmost sensor pixel 3 among the sensor pixels 3 where the detection intensity of the photodiode 30 saturates and the second pixel data Cap2 has the maximum gradation.

[0089] In the second image IM2, the gray level obtained by subtracting a margin of several gray levels from the gray level of the leftmost sensor pixel 3-b, which is the maximum gray level, is set as the first threshold value ARU.

[0090] The first threshold value ARU and the second threshold value ARL are determined when the detection device 1 is designed, and are stored in advance in the threshold value storage circuit 73 (see FIG. 2). Note that the size of the margin in setting the first threshold value ARU and the second threshold value ARL is set for each detection device 1 according to the variation in the detection sensitivity of the photodiode 30 and the variation in the amount of light of the light source 82.

[0091] Next, a more detailed method for generating a composite image IM-C will be described with reference to Fig. 10. Fig. 10 is a flow chart showing a method for generating a composite image of the detection device according to the first embodiment. In Fig. 10, the steps of capturing a first image IM1 with low sensitivity and a second image IM2 with high sensitivity described in Figs. 7 and 8 are omitted. In Fig. 10, the first image IM1 including the first pixel data Cap1 and the second image IM2 including the second pixel data Cap2 are stored in advance in a pixel data storage circuit 71 of the host IC 70.

[0092] As shown in FIG. 10, the host IC 70 sets the analysis target pixel number n to n=0 (step ST1).

[0093] Next, the host IC 70 sets the sensor pixel number p to 1 (step ST2).

[0094] The arithmetic circuit 72 acquires the second pixel data Cap2(p) in the second image IM2 from the pixel data storage circuit 71, and determines whether the second pixel data Cap2(p) is in the range from the second threshold value ARL to the first threshold value ARU (step ST3).

[0095] If the second pixel data Cap2(p) is in the range between the second threshold value ARL and the first threshold value ARU (step ST3, Yes), the arithmetic circuit 72 selects the second pixel data Cap2(p) of the sensor pixel number p as the analysis target. The host IC 70 sets the analysis target pixel number n to n=n+1 (step ST4).

[0096] The arithmetic circuit 72 acquires the first pixel data Cap1(p) in the first image IM1 corresponding to the sensor pixel number p selected as the analysis target, and calculates the gradation ratio R(n) (step ST5). The gradation ratio R(n) is the ratio between the first pixel data Cap1(p) in the first image IM1 with low sensitivity and the second pixel data Cap2(p) in the second image IM2 with high sensitivity, and is calculated based on the following formula (1).

[0097] R(n)=(Cap1(p)) / (Cap2(p)) ··· (1)

[0098] If the second pixel data Cap2(p) is not within the range of the second threshold value ARL or more and the first threshold value ARU or less (step ST3, No), the arithmetic circuit 72 does not select the second pixel data Cap2(p) of the sensor pixel number p as an analysis target. In this case, the host IC 70 skips steps ST4 and ST5 and proceeds to step ST6.

[0099] Next, the host IC 70 judges whether the sensor pixel number p is the final value (step ST6). If the sensor pixel number p is not the final value (step ST6, No), the host IC 70 updates the sensor pixel number p to p=p+1 (step ST7) and executes the calculations from step ST3 to step ST5 for all sensor pixel numbers p.

[0100] If the sensor pixel number p is the final value (step ST6, Yes), the host IC 70 determines whether the analysis target pixel number n is n>0 (step ST8). That is, the host IC 70 determines whether the second pixel data Cap2(p) selected as the analysis target in step ST3 exists.

[0101] If the analysis target pixel number n is n>0 (step ST8, Yes), the calculation circuit 72 calculates the conversion coefficient RCnv based on the following formula (2) (step ST9). In formula (2), R(n) is the gradation ratio R(n) obtained by formula (1). As shown in formula (2), the conversion coefficient RCnv is the average value of the gradation ratios R(n).

[0102]

number

[0103] If the analysis target pixel number n is not n>0 (step ST8, No), that is, if there is no second pixel data Cap2(p) selected as the analysis target in step ST3, the calculation circuit 72 sets the conversion coefficient RCnv to the standard conversion ratio Rdef (step ST10). The standard conversion ratio Rdef is determined when the detection device 1 is designed, and is stored in advance in a storage circuit (for example, the threshold storage circuit 73 (see FIG. 2)).

[0104] Next, the host IC 70 sets the sensor pixel number p to 1 (step ST11).

[0105] The arithmetic circuit 72 acquires the second pixel data Cap2(p) in the second image IM2 from the pixel data storage circuit 71, and determines whether the second pixel data Cap2(p) is equal to or smaller than the first threshold value ARU (step ST12).

[0106] If the second pixel data Cap2(p) is equal to or smaller than the first threshold value ARU (step ST12, Yes), in other words, if the detection intensity of the photodiode 30 at the sensor pixel number p is not saturated, the arithmetic circuit 72 calculates the composite pixel data Comp(p) based on the following formula (3) (step ST13). As shown in formula (3), for a sensor pixel 3 where the detection intensity of the photodiode 30 is not saturated, the composite pixel data Comp(p) is calculated by multiplying the second pixel data Cap2(p) by a conversion coefficient RCnv.

[0107] Comp(p)=Cap2(p)×Rcnv (3)

[0108] If the second pixel data Cap2(p) is greater than the first threshold value ARU (step ST12, No), in other words, if the detection intensity of the photodiode 30 at sensor pixel number p is saturated, the arithmetic circuit 72 calculates the composite pixel data Comp(p) based on the following formula (4) (step ST14). As shown in formula (4), in the sensor pixel 3 where the detection intensity of the photodiode 30 is saturated, the composite pixel data Comp(p) is set to the first pixel data Cap1(p) in the first image IM1 without using the second pixel data Cap2(p).

[0109] Comp(p) = Cap1(p) (4)

[0110] Next, the host IC 70 judges whether the sensor pixel number p is the final value (step ST15). If the sensor pixel number p is not the final value (step ST15, No), the host IC 70 updates the sensor pixel number p to p=p+1 (step ST16) and executes the calculation of the composite pixel data Comp(p) in steps ST12 to ST14 for all sensor pixel numbers p.

[0111] If the sensor pixel number p is the final value (step ST15, Yes), the image generating circuit 76 generates a composite image IM-C using the composite pixel data Comp(p) (step ST17).

[0112] In the above-described manner, the detection device 1 of the first embodiment can generate a composite image IM-C based on the first pixel data Cap1 selected in the first image IM1 and the second pixel data Cap2 selected in the second image IM2.

[0113] As a result, the detection device 1 can suppress the occurrence of noise on the low gradation side in the low-sensitivity first image IM1, and can suppress saturation of the detection intensity of the photodiode 30 in the high-sensitivity second image IM2, thereby generating a composite image IM-C with good gradation expression from the low gradation side to the high gradation side. As shown in steps ST12 to ST14, the composite pixel data Comp is calculated mainly using the high-sensitivity second image IM2. As a result, a high-sensitivity composite image IM-C can be generated.

[0114] In this embodiment, a conversion coefficient RCnv is calculated using the first pixel data Cap1 of the first image IM1 and the second pixel data Cap2 of the second image IM2, and the selected second pixel data Cap2 is multiplied by the conversion coefficient RCnv to generate composite pixel data Comp. This makes it possible to suppress degradation in image quality of the composite image IM-C compared to when images with different sensitivities are simply synthesized or when multiple images are synthesized using a unique coefficient that is set in advance.

[0115] 10 is merely an example and can be modified as appropriate. For example, the calculation of the gradation ratio R(n) in step ST5 is not limited to using the first pixel data Cap1 and the second pixel data Cap2 as is, and data obtained by subtracting (or adding) a predetermined offset value from the first pixel data Cap1 and the second pixel data Cap2 may be used.

[0116] Second embodiment Fig. 11 is a plan view showing a schematic configuration example of a plurality of light sources of the detection device according to the second embodiment. Fig. 12 is a timing waveform diagram for explaining an operation example of the detection device according to the second embodiment. In the following explanation, the same components as those explained in the above-mentioned embodiment are given the same reference numerals, and the duplicated explanation is omitted.

[0117] As shown in FIG. 11, in a light source device 80A according to the second embodiment, the multiple light sources 82 include light sources 82-R, 82-G, and 82-B. The light source 82-R (first light source) emits red light. The light source 82-G (second light source) emits green light. The light source 82-B (third light source) emits blue light. The light sources 82-R, 82-G, and 82-B are arranged side by side in this order. However, this is not limited thereto, and the arrangement of the light sources 82-R, 82-G, and 82-B can be changed as appropriate. Furthermore, the multiple light sources 82 may be configured with four or more colors.

[0118] 12, during the detection period T1, the light source 82-R, the light source 82-G, and the light source 82-B are turned on in a time-division manner. More specifically, the detection period T1 is divided into a plurality of detection periods T1-1, T1-2, and T1-3, and during each of the detection periods T1-1, T1-2, and T1-3, the light source 82-R, the light source 82-G, and the light source 82-B are turned on in a time-division manner and each emits a first amount of light.

[0119] The detection control circuit 11 processes the detection signals Vdet from the multiple photodiodes 30 during each of the detection periods T1-1, T1-2, and T1-3, and outputs first pixel data Cap1-R, Cap1-G, and Cap1-B corresponding to each color.

[0120] During the detection period T2, the light source 82-R, the light source 82-G and the light source 82-B are turned on in a time-division manner during the detection periods T2-1, T2-2 and T2-3 to irradiate a second amount of light greater than the first amount of light.

[0121] The detection control circuit 11 processes the detection signals Vdet from the multiple photodiodes 30 during each of the detection periods T2-1, T2-2, and T2-3, and outputs second pixel data Cap2-R, Cap2-G, and Cap2-B corresponding to each color.

[0122] Thus, in the second embodiment, the detection device 1 captures a first image IM1 corresponding to red light, green light, and blue light, respectively, based on the first pixel data Cap1-R, Cap1-G, and Cap1-B, and also captures a second image IM2 corresponding to red light, green light, and blue light, respectively, based on the second pixel data Cap2-R, Cap2-G, and Cap2-B.

[0123] Although not shown in the figures, in the second embodiment, the calculation of the gradation ratio R(n) and the conversion coefficient RCnv shown in steps ST3 to ST10 of FIG. 10 for each color, and the calculation of the composite pixel data Comp shown in steps ST12 to ST14 are performed for all sensor pixels 3.

[0124] In this embodiment, a conversion coefficient RCnv-R corresponding to red light, a conversion coefficient RCnv-G corresponding to green light, and a conversion coefficient RCnv-B corresponding to blue light are calculated in step ST9 in Fig. 10. Then, based on the following formula (5), the average value of the conversion coefficients RCnv-R, RCnv-G, and RCnv-B corresponding to R, G, and B is calculated as the conversion coefficient RCnv.

[0125] RCnv=(RCnv-R, RCnv-G, RCnv-B) / 3 ··· (5)

[0126] Using the conversion coefficient RCnv obtained by equation (5), the composite pixel data Comp corresponding to each of RGB can be calculated, as in the first embodiment, to generate a composite color image IM-C.

[0127] (Modification of the second embodiment) Fig. 13 is a plan view showing an optical sensor and a color filter of a detection device according to a modification of the second embodiment. In the above-mentioned second embodiment, the configuration in which light sources 82-R, 82-G, and 82-B are provided to capture a color image has been described, but the present invention is not limited to this. As shown in Fig. 13, the detection device 1 according to the modification of the second embodiment has a color filter 52 provided on the optical sensor 10.

[0128] The color filter 52 includes, for example, a color filter 52R that transmits red light, a color filter 52G that transmits green light, and a color filter 52B that transmits green light. The color filters 52R, 52B, and 52G are arranged such that filters of different colors are arranged for each sensor pixel 3 (photodiode 30).

[0129] 13, color filters 52R and 52G are alternately arranged in the first direction Dx in correspondence with the first row of sensor pixels 3 arranged in the first direction Dx. Color filters 52B and 52G are alternately arranged in the first direction Dx in correspondence with the second row of sensor pixels 3. Color filters 52R and 52G are adjacent to each other in the second direction Dy, and color filters 52B and 52G are adjacent to each other.

[0130] In a modified example, the multiple light sources 82 of the light source device 80 emit white light. Of the light emitted from the light sources 82, the light of the colors corresponding to the color filters 52R, 52B, and 52G are incident on the photodiodes 30 of the optical sensor 10. The photodiode 30 overlapping with the color filter 52R outputs a detection signal Vdet corresponding to red light. The photodiode 30 overlapping with the color filter 52G outputs a detection signal Vdet corresponding to green light. The photodiode 30 overlapping with the color filter 52B outputs a detection signal Vdet corresponding to blue light.

[0131] The detection control circuit 11 performs signal processing on the detection signals Vdet from the multiple photodiodes 30, and outputs the first pixel data Cap1-R, Cap1-G, Cap1-B and the second pixel data Cap2-R, Cap2-G, Cap2-B corresponding to each color for each sensor pixel 3. This allows the detection device 1 according to the modified example to generate a composite image IM-C of a color image, similar to the above-mentioned second embodiment. Also, in the modified example of the second embodiment, the influence of the adjacent light source 82 can be suppressed by making the adjacent color filters 52R, 52B, 52G and the light sources 82-R, 82-G, 82-B different colors.

[0132] 13 is merely an example and may be modified as appropriate. For example, the color filters 52R, 52G, and 52B may be arranged in this order in the first direction Dx. The color filters 52 are not limited to three colors and may be four or more colors.

[0133] Third embodiment Fig. 14 is an explanatory diagram for explaining a luminance correction method for a composite image in the detection device according to the third embodiment. Fig. 14 shows schematic gradation distributions along dashed lines A, B, and C for a composite image IM-C (left diagram in Fig. 14), luminance gradient data IM-D (center diagram in Fig. 14), and a corrected composite image IM-Ca (right diagram in Fig. 14), respectively.

[0134] As shown in the left diagram of Fig. 14, the composite image IM-C generated in step ST17 (see Fig. 10) may have a distribution of gradations depending on the distance from the light source 82. For example, the composite image IM-C in a region corresponding to one light source 82 is brighter the closer to the center of the composite image IM-C, i.e., the center of the light source 82, and darker the periphery of the composite image IM-C, i.e., the farther from the center of the light source 82. In this case, gradation variations occur depending on the position in the composite image IM-C, and the object 100 may not be detected well.

[0135] In the detection device 1 according to the third embodiment, a memory circuit (e.g., threshold memory circuit 73) stores luminance gradient data IM-D shown in the center diagram of FIG. 14. The luminance gradient data IM-D is information on luminance according to the distance from each of the multiple light sources 82 in a planar view. The luminance gradient data IM-D is information obtained based on a composite image IM-C acquired for the mounting substrate 110 and the culture medium 102 in the absence of the detection object 100. The memory circuit (e.g., threshold memory circuit 73) also stores in advance information on a correction value based on the luminance gradient data IM-D. The correction gradation Lc is calculated based on the following formula (6) and stored in the memory circuit (e.g., threshold memory circuit 73).

[0136] Lc(x)=(Ls(x) / Lp(x))×S (6)

[0137] In formula (6), x is the pixel coordinate in the first direction Dx. Lc is the correction gradation. Ls is the acquired gradation (synthetic pixel data Comp) acquired based on the synthetic image IM-C. Lp is the reference gradation distribution based on the luminance gradient data IM-D. S is an adjustment coefficient.

[0138] As shown in FIG. 14, the host IC 70 includes an image processing circuit 79. The image processing circuit 79 performs luminance correction of the composite image IM-C based on the luminance gradient data IM-D. More specifically, the image processing circuit 79 multiplies the composite image IM-C generated in step ST17 (see FIG. 10) by the correction gradation Lc stored in advance in a storage circuit (for example, a threshold storage circuit 73) to obtain a corrected composite image IM-Ca (right diagram in FIG. 14) in which the gradation distribution is corrected. In the corrected composite image IM-Ca, the gradation distribution characteristics of the background are substantially constant regardless of position, and a gradation according to the transmittance of the object to be detected 100 is obtained regardless of position. The detection device 1 according to the third embodiment can improve the detection accuracy.

[0139] 14, an example in which the luminance correction is performed on the composite image IM-C has been described, but the present invention is not limited to this. If necessary, the luminance correction may be performed on at least one of the first image IM1 and the second image IM2.

[0140] Although the preferred embodiment of the present invention has been described above, the present invention is not limited to such an embodiment. The contents disclosed in the embodiment are merely examples, and various modifications are possible within the scope of the present invention. Appropriate modifications made within the scope of the present invention naturally belong to the technical scope of the present invention. At least one of various omissions, substitutions, and modifications of components can be made within the scope of the gist of each of the above-mentioned embodiments and each modified example. [Explanation of symbols]

[0141] 1. Detection device 2 Array Board 3, 3-a, 3-b Sensor pixels 10 Optical Sensor 11 Detection control circuit 12 Light source control circuit 21 Substrate 30 Photodiode 52, 52R, 52G, 52B Color Filters 70 Host IC 71 Pixel data storage circuit 72 Arithmetic circuit 73 Threshold memory circuit 76 Image Generation Circuit 80, 80A light source device 81 Light source board 82, 82-R, 82-G, 82-B light source 100, 100A, 100B, 100C Object to be detected 102 Culture medium 110 Mounting Board Cap pixel data Cap1 1st pixel data Cap2 2nd pixel data Comp, Comp(p) Composite pixel data IM1 1st image IM2 2nd image IM-C composite image

Claims

1. A light source; an optical sensor including a plurality of photodiodes that outputs pixel data according to the amount of light irradiated thereon; The optical sensor captures a first image including a plurality of first pixel data and a second image including a plurality of second pixel data and having a higher sensitivity than the first image; selecting the second pixel data having a gradation equal to or less than a predetermined threshold value in the second image; selecting the first pixel data in a region corresponding to the unselected second pixel data in the first image; generating a composite image based on the selected second pixel data and the selected first pixel data; Detection device.

2. a first detection period during which the first image is captured and a second detection period during which the second image is captured, During the first detection period, the light source emits a first amount of light, and the optical sensor captures the first image in response to the first amount of light; In the second detection period, the light source emits a second amount of light that is greater than the first amount of light, and the optical sensor captures the second image in response to the second amount of light. The detection device according to claim 1 .

3. The second amount of light is greater than or equal to one of the luminance of the light source and the irradiation time of the light source.

3. The detection device according to claim 2.

4. an arithmetic circuit for selecting the second pixel data in the second image and for selecting the first pixel data in the first image; an image generating circuit for generating the composite image; the arithmetic circuit calculates composite pixel data by multiplying the selected second pixel data by a predetermined conversion coefficient; The image generating circuit generates the composite image based on the composite pixel data and the selected first pixel data. The detection device according to claim 1 .

5. The optical sensor has a light-transmitting mounting substrate disposed between the light source and the optical sensor, on which an object to be detected is mounted. The detection device according to claim 1 .

6. The light source is a point light source. The detection device according to claim 1 .

7. the light source includes a first light source that emits red light, a second light source that emits green light, and a third light source that emits blue light; The optical sensor captures the first image and the second image corresponding to red light, green light, and blue light, respectively. The detection device according to claim 1 .

8. Selecting the second pixel data corresponding to red light, green light, and blue light, respectively; generating the composite image using composite pixel data obtained by multiplying the second pixel data corresponding to each of the selected red light, green light, and blue light by a predetermined conversion coefficient; The predetermined conversion coefficient is a value obtained by averaging a conversion coefficient corresponding to red light, a conversion coefficient corresponding to green light, and a conversion coefficient corresponding to blue light.

8. The detection device according to claim 7.

9. a memory circuit for storing luminance gradient data according to a distance from the light source to each of the photodiodes; The luminance of the composite image is corrected based on the luminance gradient data. The detection device according to claim 1 .

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