Detection device

Abstract

To provide a detection device capable of sufficiently effectively utilizing potential of a sensor part.SOLUTION: A detection device comprises: a sensor part in which a photodiode for detecting light is provided and which generates an output corresponding a degree of the detected light; and a detection circuit which obtains the output of the sensor part. A plurality of sensor parts is provided. In the photodiode, a reference potential is given to an anode, and a reset potential which is higher than the reference potential is given to a cathode. The sensor part generates an output corresponding to a degree of light detected by the photodiode after the reset potential is given to the cathode and before the reset potential is given again to the cathode. A first period F1 in which outputs of the plurality of sensor parts are obtained and a second period F2 in which outputs of the plurality of sensor parts are obtained after the first period F1 are generated. The reference potential and the reset potential are different in the first period F1 and the second period F2.SELECTED DRAWING: Figure 6

Description

[Technical field]

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

[0002] 2. Description of the Related Art There is known a detection device that enables detection of the state of a culture environment for biological tissues or microorganisms by an optical sensor (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2005-87005 A Summary of the Invention [Problem to be solved by the invention]

[0004] The dynamic range of light and dark detected in the above-mentioned detection device is restricted by the narrower of a first dynamic range defined by the upper and lower limits of the output of a sensor unit provided with a light receiving element, and a second dynamic range defined by the upper and lower limits of the input accepted by a circuit that obtains the output of the sensor unit. Here, if the second dynamic range is narrower than the first dynamic range, the potential of the sensor unit cannot be fully utilized.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a detection device that can fully utilize the potential of a sensor unit. [Means for solving the problem]

[0006] A detection device according to one embodiment of the present disclosure includes a sensor unit having a photodiode that detects light and generates an output according to the level of light detected, and a detection circuit that obtains the output of the sensor unit, wherein a plurality of the sensor units are provided, the photodiode has an anode to which a reference potential is applied and a cathode to which a reset potential higher than the reference potential is applied, the sensor unit generates an output according to the level of light detected by the photodiode after the reset potential is applied to the cathode and before the reset potential is applied to the cathode again, a first period is generated in which outputs of the plurality of sensor units are obtained, and a second period is generated after the first period in which outputs of the plurality of sensor units are obtained, and the reference potential and the reset potential are different between the first period and the second period. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram showing the main configuration of the detection device. [Diagram 2] FIG. 2 is a diagram showing an example of the configuration of a detection area and a wiring area. [Diagram 3] FIG. 3 is a circuit diagram showing the circuit configuration of the sensor unit. [Figure 4] FIG. 4 is a circuit diagram for explaining the behavior of a circuit related to the output of a signal to a signal line and the transmission of the output to a detection circuit. [Diagram 5] FIG. 5 is a schematic diagram showing an embodiment of the detection device during operation. [Figure 6] FIG. 6 is a graph showing the relationship between the signal strength recognized by the AFE and the coordinates of the detection area. [Figure 7] FIG. 7 is a schematic diagram showing the mechanism of signal synthesis processing. [Figure 8] FIG. 8 is a timing chart showing an example of main signal control in the first period F1 and the second period F2 when the bias current is changed when the bias current reaches a ceiling. [Figure 9] FIG. 9 is a timing chart showing an example of main signal control in the first period F1 and the second period F2 when the initial potential is changed in the case where the potential has reached a ceiling. [Figure 10] FIG. 10 is a flowchart showing the flow of processing accompanying the sensor scan. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, each embodiment of the present disclosure will be described with reference to the drawings. Note that the disclosure is merely an example, and those who are skilled in the art can easily come up with appropriate modifications while maintaining the gist of the invention 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 specification and each figure, elements similar to those described above with respect to the previous figures may be given the same reference numerals, and detailed explanations may be omitted as appropriate.

[0009] 1 is a diagram showing the main configuration of a detection device 1. The detection device 1 includes a sensor panel 10 and a light source panel 20. The sensor panel 10 and the light source panel 20 are connected to a host 30.

[0010] The sensor panel 10 has a detection area SA (see FIG. 2) provided on a substrate 11. A reset circuit 13, a scanning circuit 14, and a wiring area VA are also mounted on the substrate 11. The configuration on the detection area SA, the reset circuit 13, and the scanning circuit 14 are connected to a detection circuit 15 via the wiring area VA.

[0011] The light source panel 20 has a light emitting area LA that irradiates light onto the detection area SA. The light source panel 20 has a light source 22 provided on a substrate 21. The light source 22 is a light emitting element such as an LED (Light Emitting Diode), and is arranged within the light emitting area LA. In the example shown in FIG. 1, a plurality of light sources 22 are arranged in a matrix on the substrate 21.

[0012] The plurality of light sources 22 are provided so that their light emission can be controlled individually. The light source panel 20 is provided with a light source drive circuit 23. Under the control of the host 30, the light source drive circuit 23 controls whether each of the plurality of light sources 22 is turned on and the luminance when turned on.

[0013] The host 30 performs various controls related to the operation of the detection device 1. Specifically, the host 30 is, for example, a microcontroller corresponding to the configuration of the detection device 1 or an information processing device that functions similarly to a microcontroller. The host 30 is connected to the detection circuit 15 via a standardized interface such as a Serial Peripheral Interface (SPI) and obtains an output from the detection circuit 15. The host 30 is also connected to the light source drive circuit 23 via the standardized interface and performs processes related to the lighting of the light source 22, such as determining the lighting pattern of the light source 22.

[0014] Fig. 2 is a diagram showing an example of the configuration of the detection area SA and wiring area VA. A plurality of sensor units WA (Fig. 3) are provided in the detection area SA. In the embodiment, as shown in Fig. 2, the plurality of sensor units WA are arranged in a matrix along the first direction Dx and the second direction Dy. The first direction Dx and the second direction Dy are orthogonal. In the following description, the third direction Dz refers to a direction orthogonal to the first direction Dx and the second direction Dy.

[0015] The reset circuit 13 is connected to the reset signal transmission lines 51, 52, ..., 5n. Hereinafter, when the reset signal transmission line 5 is described, it refers to any one of the reset signal transmission lines 51, 52, ..., 5n. The reset signal transmission line 5 is wiring along the first direction Dx. In the example shown in FIG. 2, n reset signal transmission lines 5 are arranged in the second direction Dy. n is a natural number equal to or greater than 2. The n reset signal transmission lines 5 are connected to the reset circuit 13 at one end side in the first direction Dx.

[0016] The scanning circuit 14 is connected to the scanning lines 61, 62, . . . , 6n. Hereinafter, when a scanning line 6 is described, it refers to any one of the scanning lines 61, 62, . . . , 6n. The scanning lines 6 are wirings along the first direction Dx. In the example shown in FIG. 2, n scanning lines 6 are arranged in the second direction Dy. The n reset signal transmission lines 5 are connected to the scanning circuit 14 at the other end side in the first direction Dx.

[0017] 2, the reset signal transmission lines 5 and the scanning lines 6 are arranged alternately in the second direction Dy within the detection area SA. Note that, although the reset circuit 13 and the scanning circuit 14 illustrated in Fig. 1 and Fig. 2 are arranged at positions facing each other with the detection area SA in between, the layout of the reset circuit 13 and the scanning circuit 14 is not limited to this and can be changed as appropriate.

[0018] Furthermore, signal lines 71, 72, ..., 7m are provided within the detection area SA. Hereinafter, when the signal line 7 is described, it refers to any one of the signal lines 71, 72, ..., 7m. The signal line 7 is a wiring that extends along the second direction Dy.

[0019] 2, m signal lines 7 are arranged in a first direction Dx, where m is a natural number equal to or greater than 2. Each of the m signal lines 7 is connected at one end in the second direction Dy to one of a plurality of switches (for example, switch SW1, switch SW2, switch SW3, or switch SW4) included in the selector circuit 40.

[0020] The selector circuit 40 is provided in the wiring area VA. The selector circuit 40 has a plurality of switches. In the example shown in FIG. 2, the switches SW1, SW2, SW3, and SW4 are shown as the plurality of switches. The plurality of switches in one selector circuit 40 are turned ON (connected state) at different timings. Among the plurality of switches in one selector circuit 40, while one switch is ON (connected state), the other switches are OFF (disconnected state). The number of selector circuits 40 corresponds to the number (m) of signal lines 7. If the number of switches is p, the number of selector circuits 40 needs to be m / p. When there are a plurality of selector circuits 40, the plurality of selector circuits 40 are connected to the detection circuit 15 via individual wirings 401, 402, . . . , 40p.

[0021] Note that the connection between the signal line 7 and the detection circuit 15 via the selector circuit 40 is merely an example and is not limiting, and the signal line 7 may be directly connected to the detection circuit 15 individually within the wiring area VA. Within the wiring area VA, the reset circuit 13 is connected to the detection circuit 15 via a wiring 131. Within the wiring area VA, the scanning circuit 14 is connected to the detection circuit 15 via a wiring 141.

[0022] The detection circuit 15 is involved in the detection of light by the PD 82 (see FIG. 3) provided in the sensor unit WA, and controls the operation timing of the reset circuit 13 and the scanning circuit 14. In this way, the detection circuit 15 controls the timing of the reset period RT, the exposure period EX, and the readout period RD of the sensor unit WA, which will be described later with reference to FIG. 8 and FIG. 9. The detection circuit 15 also receives an output from the sensor unit WA. The detection circuit 15 converts the signal input from the sensor unit WA into data that can be interpreted by the host 30, and outputs the converted data to the host 30. The detection circuit 15 in the embodiment is a ROIC (Read Out Integrated Circuit) of the multiple sensor units WA in the sensor panel 10.

[0023] Fig. 3 is a circuit diagram showing the circuit configuration of the sensor unit WA. Note that the first direction Dx and the second direction Dy in Fig. 3 merely correspond to the directions of the reset signal transmission line 5, the scanning line 6, and the signal line 7, and do not strictly indicate the relative positional relationship of the circuit configuration in the sensor unit WA.

[0024] 3, the sensor unit WA includes a switching element 81, a PD 82, a transistor element 83, and a switching element 85. The PD 82 is a photodiode (PD: PhotoDiode). The switching elements 81, 83, and 85 are MOSFETs (Metal Oxide Semiconductor Field Effect Transistors).

[0025] The gate of the switching element 81 is connected to the reset signal transmission line 5. A reset potential VReset is applied to one of the source or drain of the switching element 81. The cathode of PD82 and the gate of the transistor element 83 are connected to the other of the source or drain of the switching element 81. Hereinafter, when the connection part CP is described, it refers to the point where the other, that is, the cathode of PD82 and the gate of the transistor element 83 are connected. In addition, a reference potential VCOM is applied from the anode side of PD82. The potential difference between the reset potential VReset and the reference potential VCOM is predetermined, but the potentials of the reset potential VReset and the reference potential VCOM may be variable. Incidentally, the reset potential VReset is a potential higher than the reference potential VCOM.

[0026] An output source potential VPP2 is applied to the drain of the transistor element 83 functioning as a source follower. One of the source or drain of the switching element 85 is connected to the source of the transistor element 83. The other of the source or drain of the switching element 85 is connected to the signal line 7. The gate of the switching element 85 is connected to the scanning line 6.

[0027] The reset potential VReset, the reference potential VCOM, and the output source potential VPP2 are supplied to the sensor unit WA by the detection circuit 15 based on, for example, power supplied via a power supply circuit (not shown) connected to the detection circuit 15, but are not limited to this and can be changed as appropriate.

[0028] The output source potential VPP2 is determined in advance. The potential on the source side of the transistor element 83 is a potential that is lower than the output potential of the PD82 by the gate-source voltage (Vth) of the transistor element 83. In this case, the potential on the source side of the transistor element 83 depends on the reset potential VReset and the potential of the reference potential VCOM. The potential of the output of the PD82 depends on the photoelectromotive force generated by the PD82 in response to the light detected by the PD82 during the exposure period EX described later.

[0029] When the gate of the switching element 85 is turned ON by a signal provided from the scanning circuit 14 via the scanning line 6, the source and drain of the switching element 85 are connected. As a result, the signal (electric potential) transmitted to the switching element 85 via the transistor element 83 is transmitted to the signal line 7 through the switching element 85. In this manner, an output is generated from the sensor unit WA. Hereinafter, the term "scanning signal" refers to the signal (electric potential) provided from the scanning circuit 14 via the scanning line 6. The scanning circuit 14 is a circuit that outputs the scanning signal.

[0030] The output of one PD82 provided on one sensor unit WA corresponds to the intensity of light detected by that PD82 within a predetermined exposure period EX (see Figures 8 and 9). The output of the PD82 is reset in response to a signal provided from the reset circuit 13 via a reset signal transmission line 5. When the signal turns on the gate of the switching element 81, the source and drain of the switching element 81 are connected. This resets the potential of the connection point CP to the reset potential VReset. Hereinafter, when the term "initial potential" is used, it refers to this reset potential VReset.

[0031] Moreover, when described as a reset signal, it refers to a signal provided from the reset circuit 13 via the reset signal transmission line 5. The reset circuit 13 is a circuit that outputs a reset signal.

[0032] Hereinafter, the output of a signal to the signal line 7 and the transmission of the output to the detection circuit 15 will be described in detail with reference to FIG.

[0033] FIG. 4 is a circuit diagram for explaining the behavior of the circuit related to the output of a signal to the signal line 7 and the transmission of the output to the detection circuit 15. As described above, once the output of PD82 is reset, the potential of the connection part CP becomes the initial potential. The charge accumulated in the capacitance C1 is discharged from PD82 according to the intensity of the light detected by PD82 until the output of PD82 is reset again, so that the potential of the connection part CP drops. In FIG. 4, the electrostatic capacitance at the connection part CP is indicated by capacitance C1. Therefore, it can be said that the source potential of the transistor element 83 corresponds to the capacitance C1. If PD82 does not detect any light, substantially no current flows through PD82, so the potential across the capacitance C1 does not change from the initial potential. According to the degree to which PD82 detects light, the capacitance C1 changes in a direction lower than the initial potential.

[0034] Here, the capacitance at the connection point between the source of the transistor element 83 and one of the source or drain of the switching element 85 is defined as capacitance C2. Also, the capacitance corresponding to the other of the source or drain of the switching element 85 is defined as capacitance C3. The source and drain of the switching element 85 are connected by outputting a scanning signal.

[0035] The signal line 7 interposed between the other of the source or drain of the switching element 85 and the AFE 31 provided in the detection circuit 15 has an electric resistance ER according to its extension length. Here, a current source 32 is provided so as to branch off from the signal line 7. The current source 32 causes a constant current to flow out of the signal line 7, so that a voltage according to the current value flowing through the electric resistance ER is generated between the other of the source or drain of the switching element 85 and the AFE 31. The capacitance C4 is, for example, a capacitance that stabilizes the potential of the signal line 7. Hereinafter, when the term "bias current" is used, it refers to a current that is provided (flowed out) from the current source 32 to the signal line 7. The current source 32 is a current source that provides a bias current, and is provided, for example, in the detection circuit 15.

[0036] As shown in FIG. 4, the capacitance C1 can be regarded as a capacitance element having one end connected to a signal line (connection part CP) and the other end to which a reference potential (GND) is applied. The capacitance C2 can be regarded as a capacitance element having one end connected to a signal transmission path between the transistor element 83 and the switching element 85 and the other end to which a reference potential (GND) is applied. The capacitance C3 can be regarded as a capacitance element having one end connected to a signal transmission path between the switching element 85 and the detection circuit 15 and the other end to which a reference potential (GND) is applied. The capacitance C4 can be regarded as a capacitance element having one end connected to a signal transmission path between the switching element 85 and the detection circuit 15 and the other end to which a reference potential (GND) is applied. The capacitances C1 to C4 may not be capacitance elements, but may be parasitic capacitances of the respective elements.

[0037] Furthermore, when the potential of the connection part CP is changed from the initial potential, the potential of the transistor element 83 is also changed. That is, when the initial potential is changed, the potential of the signal line 7 is changed accordingly. Therefore, the potential of the signal line 7 can be controlled by controlling the initial potential. Furthermore, when the bias current is changed, the potential difference across the electrical resistance ER is also changed, and therefore the potential of the signal line 7 can also be changed.

[0038] The AFE 31 is a circuit that functions as an analog front end. The AFE 31 generates a signal according to an input given via a signal line 7 and outputs the signal to the host 30.

[0039] Next, the operation of the detection device 1 will be described with reference to FIG.

[0040] FIG. 5 is a schematic diagram showing the operation of the detection device 1. The detection device 1 is provided such that the light source panel 20 and the sensor panel 10 face each other in the third direction Dz with the detection object SUB in between. The detection object SUB is, for example, a petri dish on which a medium such as an agar medium is formed, but is not limited thereto and may have another configuration that transmits light from the light source panel 20. The detection object SUB is placed in the detection area SA on the substrate 11. The light source panel 20 irradiates light from above the detection object SUB toward the sensor panel 10 by turning on the light source 22. FIG. 5 shows a case where the light source 22 located near the center in the first direction Dx is turned on. Also, FIG. 5 shows the spread of light emitted from the light source 22 toward the detection object SUB as an illumination range 220. Of the light emitted from the light source 22 toward the detection object SUB, the light that has passed through the detection object SUB is detected by the PD82 (see FIGS. 3 and 4) in the detection area SA. Hereinafter, when the term "sensor scan" is used, it refers to a process in which the sensor panel 10 detects light that is irradiated from the light source panel 20 and passes through the object to be detected (e.g., the object to be detected SUB) when the positional relationship between the sensor panel 10 and the light source panel 20, which face each other across the object to be detected, is established.

[0041] Even if the light source is common, the intensity of light detected by each of the multiple PDs 82 provided in the detection area SA may differ. Hereinafter, the intensity of light detected in the detection area SA will be described with reference to FIG.

[0042] FIG. 6 is a graph showing the relationship between the signal intensity recognized by the AFE31 and the coordinates of the detection area SA. Hereinafter, when simply described as signal intensity, it refers to the signal intensity recognized by the AFE31 unless otherwise specified. The signal intensity corresponds to the intensity of light detected by the PD82. In addition, "E1" among the coordinates of the detection area SA shown on the horizontal axis of the graph shown in FIG. 6 indicates one end of the detection area SA along one of the first direction Dx and the second direction Dy. In addition, "E2" indicates the other end of the detection area SA along the one. In the explanation with reference to FIG. 6, the one is described as the first direction Dx in accordance with FIG. 5. The graph in FIG. 6 is assumed to roughly show the signal intensity according to the illumination range 220 shown in FIG. 5. In addition, FIG. 6 shows a graph of the first period F1 and a graph of the second period F2.

[0043] As shown in the graph of the first period F1 in FIG. 6, the signal intensity may vary depending on the coordinates of the detection area SA. However, as shown as a peak range WH, the signal intensity remains high in the middle between the coordinates E1 and E2 and in the vicinity of the middle. This is due to the dynamic range DR of the AFE31. The dynamic range DR is determined by the lower limit (Dmin) and upper limit (Dmax) of the signal that the AFE31 can process. The peak range WH occurs due to the upper limit (Dmax) of the dynamic range DR. If there is no limit on the signal intensity due to the upper limit (Dmax), the distribution of the signal intensity according to the intensity of light detected by each of the multiple PDs 82 arranged along the horizontal axis (coordinate) shows a sinusoidal distribution formed by the solid curve W1 and the dashed curve WM in the graph of the first period F1 in FIG. 6. This is because the PD 82 that is closer relative to the lit light source 22 detects stronger light.

[0044] Conversely, in the first period F1, the output corresponding to the solid line graph formed by the solid line curve W1 and the peaking range WH is treated as "the output of one sensor scan corresponding to the lighting pattern of a certain light source 22" corresponding to the outputs from the multiple sensor units WA. In other words, the combined output of each of the multiple sensor units WA at a certain point in time (for example, a readout period RD described later) is treated as the output from the detection area SA.

[0045] As described with reference to Fig. 4, the signal strength (potential of the signal line 7) can be changed by changing at least one of the bias current and the initial potential. Therefore, when an output corresponding to the upper limit (Dmax) of the dynamic range DR occurs, such as the peaking range WH in the graph of the first period F1 in Fig. 6, the signal discrimination limit caused by the upper limit (Dmax) can be eliminated by lowering the signal strength.

[0046] The graph for the second period F2 in Fig. 6 shows that the signal intensity is lowered by the shift amount SH compared to the graph for the first period F1. As a result, in the second period F2, the AFE31 can recognize the signal intensity distribution corresponding to the solid curve W2 including the portion of the dashed curve WM that the AFE31 could not recognize in the first period F1. On the other hand, in the second period F2, the portion shown as the dashed curve WB falls below the lower limit (Dmin), and the AFE31 cannot recognize the signal or distinguish the signal intensity. In this way, by changing the signal intensity, the relationship between the distribution of signal intensity according to the light intensity detected by each of the multiple PDs 82 and the dynamic range DR can be changed.

[0047] When the difference between the lower limit and the upper limit of the signal strength in the distribution of the signal strength according to the light strength detected by each of the multiple PDs 82 exceeds the dynamic range DR, simply operating the AFE 31 cannot identify the distribution of the signal strength according to the light strength detected by each of the multiple PDs 82. In this case, by using two detection results in which the signal strength is changed, such as the first period F1 and the second period F2 described with reference to FIG. 6, the distribution of the signal strength according to the light strength detected by each of the multiple PDs 82 can be more reliably identified. Here, the shift amount (shift amount SH) of the signal strength when changing the signal strength from the first period F1 to the second period F2 is equal to or less than the difference (upper and lower difference) between the upper limit (Dmax) and the lower limit (Dmin) of the dynamic range DR. In the example shown in FIG. 6, the shift amount SH is less than the upper and lower difference. The overlap range Di shown in FIG. 6 is the difference obtained by subtracting the shift amount SH from the upper limit difference. In other words, the signal included in the overlap range Di is recognized in both the first period F1 and the second period F2. Therefore, when using the results of two detections, a signal synthesis process is performed in which measures are taken to prevent overlapping of the portions included in the overlap range Di.

[0048] FIG. 7 is a schematic diagram showing the mechanism of signal synthesis processing. In FIG. 7, the signal obtained in the first period F1 shown in FIG. 6 is shown as the first signal P1. Also, in FIG. 7, the signal obtained in the second period F2 shown in FIG. 6 is shown as the second signal P2. In the signal synthesis processing, the first signal P1 and the second signal P2 are added together, and the signal strength of the portion included in the overlap range Di is subtracted once. This makes it possible to obtain a synthetic signal WS that reflects measures against both the distribution of signal strength exceeding the dynamic range DR and the overlap of the portion included in the overlap range Di.

[0049] In the embodiment, the determination of whether a signal input corresponding to the upper limit (Dmax) of the dynamic range DR has occurred in the AFE 31 and the change of the signal intensity when such an input has occurred are performed by, for example, the detection circuit 15. Furthermore, the signal synthesis process is performed by, for example, the host 30, but the detection circuit 15 may have a function of performing the signal synthesis process. Furthermore, if the signal has not reached a ceiling, it is determined that there is no need to perform detection corresponding to the second period F2 for the signal synthesis process. The term "topping out" here refers to the signal intensity reaching the upper limit (Dmax) of the dynamic range DR at one or more coordinates. If the signal has reached a ceiling, it is impossible to distinguish whether the signal intensity is equal to or exceeds the upper limit of the dynamic range DR, so detection corresponding to the second period F2 for the signal synthesis process is performed.

[0050] In the embodiment, the signal strength is set in advance so that the signal strength when the PD82 does not detect any light at all during the first period F1 exceeds the lower limit (Dmin) of the dynamic range DR. This limits the signal strength distribution outside the dynamic range DR to those exceeding the upper limit (Dmax) of the dynamic range DR.

[0051] Next, as a specific method for changing the signal strength, a case in which the bias current is changed and a case in which the initial potential is changed will be described in turn.

[0052] Fig. 8 is a timing chart showing an example of main signal control in the first period F1 and the second period F2 when the bias current is changed when the bias current reaches a ceiling. CL1 in Fig. 8 and Fig. 9 described later indicates a reset signal. CL2 in Fig. 8 and Fig. 9 indicates a scanning signal. Vo in Fig. 8 indicates a bias current.

[0053] The light detection process, which is performed multiple times, such as the first period F1 and the second period F2, is performed in a unit time cycle. That is, the time length of the first period F1 and the time length of the second period F2 are substantially the same. In addition, the ratio of the time lengths allocated to the reset period RT, the exposure period EX, and the readout period RD included in each unit time is also substantially the same in the first period F1 and the second period F2. The start timing control of the reset period RT and the readout period RD is performed by the detection circuit 15.

[0054] Common to the first period F1 and the second period F2, first, during the reset period RT, a reset signal is provided from the reset circuit 13 to the reset signal transmission line 5. This causes the connection point CP (electric potential at one end of the capacitance C1) to become the initial electric potential. Thereafter, the electric potential at one end of the capacitance C1 and the electric potential at one end of the capacitance C2 vary according to the intensity of the light detected by the PD 82 during the exposure period EX. Then, during the readout period RD, a scanning signal is provided from the scanning circuit 14 to the scanning line 6, and the signal (electric potential) input via the signal line 7 becomes a signal intensity (electric potential) according to the electric potential at one end of the capacitance C2.

[0055] The bias current is changed at the boundary timing between the first period F1 and the second period F2. In the example shown in Fig. 8, the bias current is increased to decrease the potential level at one end of the capacitance C4. This allows the signal strength in the second period F2 to be lower than that in the first period F1, as described with reference to Fig. 6.

[0056] Fig. 9 is a timing chart showing an example of main signal control in the first period F1 and the second period F2 when the initial potential is changed when the potential reaches a ceiling. VReset in Fig. 9 indicates the reset potential VReset described with reference to Fig. 3 and Fig. 4. VCOM in Fig. 9 indicates the reference potential VCOM described with reference to Fig. 3 and Fig. 4.

[0057] The example shown in FIG. 9 differs from FIG. 8 in that the initial potential, not the bias current, is changed at the boundary timing between the first period F1 and the second period F2. Specifically, the reset potential VReset and the reference potential VCOM are lowered at the boundary timing between the first period F1 and the second period F2. This lowers the potential level at one end of the capacitance C4, so that the signal strength in the second period F2 can be lowered compared to the first period F1. As described above, FIG. 9 is the same as FIG. 8, except for the points noted above. Note that if the characteristics of the photodiode do not change regardless of the reverse bias voltage between the anode and cathode of PD82, only the reset potential VReset may be changed without changing the potential of the reference potential VCOM.

[0058] The shape of the graph showing the relationship between coordinates and signal intensity described with reference to FIG. 6 is that when the light source 22 located near the center of the light-emitting area LA is turned on, as described with reference to FIG. 5. The peak of the signal intensity distribution corresponding to the sinusoidal graph corresponds to the arrangement of the turned-on light sources 22. In the sensor scan, some (one or more) of the multiple light sources 22 are turned on, and a process of obtaining an output from the sensor unit WA according to the turning-on is repeated. The host 30 integrates the outputs obtained by such repetition, and the sensing result of the object to be detected (e.g., object to be detected SUB) is derived. In such repetition, all of the multiple light sources 22 are turned on at least once.

[0059] Although the signal strength may be changed by changing both the bias current and the initial potential, changing the signal strength by changing the bias current or the initial potential can simplify the process of changing the signal strength. The above-described flow of control will be described with reference to the flowchart of FIG.

[0060] 10 is a flow chart showing the flow of processing associated with a sensor scan. First, a sensor scan is performed (step S1). As a result of the sensor scan in step S1, it is determined whether there is a sensor unit WA that has generated an output of a signal corresponding to (or exceeding) the upper limit (Dmax) of the dynamic range DR (step S2).

[0061] If it is determined in step S2 that there is a sensor unit WA that has generated an output of a signal that corresponds to (or exceeds) the upper limit (Dmax) of the dynamic range DR (step S2; Yes), the sensor output level is shifted (step S3). Specifically, a process is performed to lower the output level of the sensor unit WA by the next sensor scan by changing the signal strength by changing at least one of the bias current and the initial potential described above.

[0062] After the process of step S3, the sensor scan is performed again (step S4). The sensor scan in step S4 corresponds to the second period F2 described above. When the process of step S4 is performed, the sensor scan in the process of step S1 corresponds to the first period F1 described above.

[0063] After the process of step S4, the output from the sensor scan of step S1 and the output from the sensor scan of step S4 are combined (step S5). Specifically, as described with reference to Fig. 7, a process is performed in which the overlapping portion of the outputs of the two sensor scans is subtracted from the sum of the outputs of the two sensor scans. The output combined by the process of step S5 is adopted as the output of the sensor scan (step S6).

[0064] On the other hand, if it is determined in step S2 that there is no sensor unit WA that has generated a signal output corresponding to the upper limit (Dmax) of the dynamic range DR (step S2; No), the output obtained in the processing of step S1 is adopted as the output of the sensor scan (step S7).

[0065] As described above, according to the embodiment, the detection device 1 includes a sensor unit WA having a PD82 that detects light and generates an output according to the degree of light detected, and a detection circuit 15 that obtains the output of the sensor unit WA, where multiple sensor units WA are provided, PD82 has a reference potential VCOM applied to its anode and a reset potential VReset applied to its cathode, and the sensor unit WA generates an output according to the degree of light detected by PD82 after the reset potential VReset is applied to the cathode and before the reset potential VReset is again applied to the cathode, a first period F1 is generated in which outputs of the multiple sensor units WA are obtained, and a second period F2 is generated after the first period F1 in which outputs of the multiple sensor units WA are obtained, and the reference potential VCOM and the reset potential VReset are different between the first period F1 and the second period F2.

[0066] Also, according to an embodiment, the detection device 1 is provided with a sensor unit WA having a PD82 that detects light and generates an output according to the degree of light detected, and a detection circuit 15 that obtains the output of the sensor unit WA, where multiple sensor units WA are provided, PD82 has a reference potential VCOM applied to its anode and a reset potential VReset applied to its cathode, a configuration (signal line 7) that functions as an electrical resistance (electrical resistance ER) is interposed between the sensor unit WA and the detection circuit 15, a current source 32 that provides a bias current is connected to the connection path between the electrical resistance and the detection circuit 15, a first period F1 is generated in which outputs from the multiple sensor units WA are obtained, and a second period F2 is generated after the first period F1 in which outputs from the multiple sensor units WA are obtained, and the bias current differs between the first period F1 and the second period F2.

[0067] Either of these can adjust the level of the signal (the above-mentioned signal intensity) input to the detection circuit 15 as the output of the sensor unit WA. Therefore, even if the range between the lower and upper limits of the output of the sensor unit WA according to the degree of light detection by the PD82 exceeds the range between the lower and upper limits that the detection circuit 15 can recognize (for example, the above-mentioned dynamic range DR), by adjusting the level in the first period F1 and the second period F2, the output of the sensor unit WA can be easily kept within the range that the detection circuit 15 can recognize through two sensing operations in the first period F1 and the second period F2. Therefore, sensing that fully utilizes the potential of the sensor unit WA, i.e., the potential of the PD82 provided in the sensor unit WA, can be realized.

[0068] Furthermore, when the outputs of the multiple sensor units WA during the first period F1 are all within the range between the lower and upper limits of the input that can be recognized by the detection circuit 15, the second period F2 is omitted. This makes it possible to omit the second period F2 when there is no need to implement the second period F2 in order to fully utilize the potential of the PD82 provided in the sensor unit WA, thereby providing a detection device with higher responsiveness.

[0069] In addition, in the first period F1 and the second period F2, the combined output of each of the multiple sensor units WA is treated as the output from the detection area SA in which the multiple sensor units WA are arranged, thereby obtaining a surface sensor output.

[0070] Furthermore, when the detection circuit 15 obtains both a first output (e.g., a first signal P1) which is an output from the detection area SA in the first period F1, and a second output (e.g., a second signal P2) which is an output from the detection area SA in the second period F2, the first output and the second output can be combined by subtracting the overlapping portion (e.g., within the overlapping range Di) between the first output and the second output from the first output or the second output, and the sensor output obtained through two sensing operations in the first period F1 and the second period F2 can be used as an output indicating the result of sensing that fully utilizes the potential of PD82 provided in the sensor unit WA.

[0071] In addition, multiple sensor units WA are arranged in a matrix, and each of the multiple sensor units WA is connected to a scanning line for transmitting a scanning signal that generates an output in the sensor unit WA and a signal line for transmitting the output from the sensor unit WA, thereby making it possible to arrange the multiple sensor units WA more efficiently.

[0072] In addition, the sensor panel 10 includes a light source 22 that emits light and has a detection area SA in which a plurality of sensor units WA are arranged, and the light source 22 faces the sensor panel 10 across a medium (e.g., a detection target SUB), so that the light emitted from the light source 22 and transmitted through the medium can be detected in the detection area SA. In other words, the state of the medium can be sensed.

[0073] Furthermore, since the range between the lower and upper limits of the input that can be recognized by the detection circuit 15 (e.g., the dynamic range DR) is smaller than the range between the lower and upper limits of the output of the sensor unit WA, the potential of the sensor unit WA can be utilized more effectively by adjusting the level in the first period F1 and the second period F2 to bring the output of the sensor unit WA within the range that can be recognized by the detection circuit 15 through two sensing operations in the first period F1 and the second period F2.

[0074] In addition, other advantageous effects brought about by the aspects described in this embodiment that are obvious from the description in this specification or that can be appropriately thought of by a person skilled in the art are naturally understood to be brought about by the present disclosure. [Explanation of symbols]

[0075] 1. Detection device 6 Scan Lines 7 Signal Line 10 Sensor Panel 15 Detection circuit 22 Light source 31 AFE 32 Current source 82 Photodiode F1 1st Period F2 2nd Period VReset Reset potential VCOM reference potential WA Sensor section

Claims

1. a sensor section provided with a photodiode for detecting light and generating an output in accordance with the level of the detected light; a detection circuit for obtaining an output of the sensor unit; A plurality of the sensor units are provided, A reference potential is applied to the anode of the photodiode, and a reset potential higher than the reference potential is applied to the cathode of the photodiode. the sensor unit generates an output according to a level of light detected by the photodiode after the reset potential is applied to the cathode and before the reset potential is applied to the cathode again; a first period in which outputs of a plurality of the sensor units are obtained, and a second period in which outputs of the plurality of the sensor units are obtained after the first period; The reference potential and the reset potential are different between the first period and the second period. Detection device.

2. a sensor section provided with a photodiode for detecting light and generating an output in accordance with the level of the detected light; a detection circuit for obtaining an output of the sensor unit; A plurality of the sensor units are provided, A reference potential is applied to the anode of the photodiode, and a reset potential higher than the reference potential is applied to the cathode of the photodiode. A configuration functioning as an electrical resistance is interposed between the sensor unit and the detection circuit, a current source that applies a bias current is connected to a connection path between the electrical resistance and the detection circuit; a first period in which outputs of a plurality of the sensor units are obtained, and a second period in which outputs of the plurality of the sensor units are obtained after the first period; The bias current is different between the first period and the second period. Detection device.

3. When the outputs of the plurality of sensor units are all within a range between a lower limit and an upper limit of an input that can be recognized by the detection circuit during the first period, the second period is omitted.

3. A detection device according to claim 1 or 2.

4. In each of the first period and the second period, a combined output of each of the plurality of sensor units is treated as an output from a detection area in which the plurality of sensor units are arranged.

3. A detection device according to claim 1 or 2.

5. when the detection circuit obtains both a first output which is an output from the detection region in the first period and a second output which is an output from the detection region in the second period, the detection circuit subtracts an overlapping portion of the first output and the second output from the first output or the second output to combine the first output and the second output; 5. The detection device according to claim 4.

6. The plurality of sensor units are arranged in a matrix, Each of the plurality of sensor units is connected to a scanning line for transmitting a scanning signal that causes the sensor unit to generate an output and a signal line for transmitting an output from the sensor unit.

3. A detection device according to claim 1 or 2.

7. A light source that emits light is provided, A sensor panel having a detection area in which a plurality of the sensor units are arranged and the light source face each other across the culture medium.

3. A detection device according to claim 1 or 2.

8. a range between a lower limit and an upper limit of an input that can be recognized by the detection circuit is smaller than a range between a lower limit and an upper limit of an output from the sensor unit; 3. A detection device according to claim 1 or 2.

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