Detection device

Abstract

Provided is a detection device capable of suppressing a reduction in detection accuracy due to time-varying changes in a reverse bias characteristic. This detection device comprises: a sensor unit that has a first photodiode and a second photodiode; and a detection circuit that detects the output of the first photodiode and the output of the second photodiode alternately. A first potential is supplied to anodes of the first photodiode and the second photodiode, a second potential lower than the first potential is supplied to a cathode of the second photodiode during a first period (1F_odd) when the output of the first photodiode is detected, and the second potential is supplied to a cathode of the first photodiode during a second period (1F_even) when the output of the second photodiode is detected.

Description

[Technical Field]

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

[0002] For example, a detection device using an optical sensor for detection is known (see, for example, Patent Document 1). In a detection device using an optical sensor, the optical sensor is reverse-biased to generate electric charges, which are converted into a voltage signal and output to a detection circuit, and the voltage signal is integrated by an integration circuit provided in the detection circuit, thereby performing detection processing. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-10054 Summary of the Invention [Problem to be solved by the invention]

[0004] Known optical sensors for detection include organic photodetectors such as organic photodiodes (OPDs). When variations occur in the organic semiconductor layer of a detection device using an OPD, variations in the reverse bias characteristics occur. Furthermore, the reverse bias characteristics may change over time, potentially reducing detection accuracy.

[0005] An object of the present invention is to provide a detection device that can suppress a decrease in detection accuracy due to changes over time in reverse bias characteristics. [Means for solving the problem]

[0006] A detection device according to one embodiment of the present invention includes a sensor unit having a first photodiode and a second photodiode, and a detection circuit that alternately detects the output of the first photodiode and the output of the second photodiode, wherein a first potential is supplied to the anodes of the first photodiode and the second photodiode, and during a first period in which the output of the first photodiode is detected, a second potential lower than the first potential is supplied to the cathode of the second photodiode, and during a second period in which the output of the second photodiode is detected, the second potential is supplied to the cathode of the first photodiode. [Brief explanation of the drawings]

[0007] [Figure 1A] FIG. 1A is a cross-sectional view showing a schematic cross-sectional configuration of a detection instrument with an illumination device having a detection device according to an embodiment. [Figure 1B] FIG. 1B is a cross-sectional view showing a schematic cross-sectional configuration of a detection instrument with an illumination device according to a modified example. [Figure 2] FIG. 2 is a plan view showing a detection device according to a comparative example. [Figure 3] FIG. 3 is a diagram showing an example of the configuration of each divided region of a detection device according to a comparative example and a connection to a detection circuit. [Figure 4] FIG. 4 is a timing chart showing an example of the operation of the detection device according to the comparative example. [Figure 5] FIG. 5 is a diagram illustrating an example of diode characteristics of an optical sensor. [Figure 6A] FIG. 6A is a diagram showing an example in which the output level in each divided region is visualized in the detection region. [Figure 6B] FIG. 6B is a diagram showing an example in which the output level in each divided region is visualized in the detection region. [Figure 7] FIG. 7 is a plan view showing the detection device according to the embodiment. [Figure 8] FIG. 8 is a diagram showing an example of the configuration of each divided area of ​​the detection device according to the embodiment and a connection to the detection circuit. [Figure 9]FIG. 9 is a timing chart showing an example of the operation of the detection device according to the embodiment. [Figure 10] FIG. 10 is a plan view showing a detection device according to a first modified example of the embodiment. [Figure 11] FIG. 11 is a plan view showing a detection device according to a second modified example of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Modes (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the contents described in the following embodiments. Furthermore, the components described below include those that can be easily imagined by a person skilled in the art and those that are substantially identical. Furthermore, the components described below can be appropriately combined. Furthermore, the disclosure is merely an example, and appropriate modifications that a person skilled in the art can easily conceive while maintaining the gist of the invention are naturally included within the scope of the present invention. Furthermore, for clarity of explanation, the drawings may show the width, thickness, shape, etc. of each part schematically compared to the actual embodiment. However, these are merely examples and are not intended to limit the interpretation of the present invention. Furthermore, in this specification and each figure, elements similar to those described above with reference to the previous figures may be designated by the same reference numerals, and detailed descriptions may be omitted as appropriate.

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

[0010] First, an application example of the detection device according to this embodiment will be described with reference to FIGS. 1A and 1B.

[0011] 1A is a cross-sectional view showing a schematic cross-sectional configuration of a detection device with an illumination device having a detection device according to an embodiment. As shown in FIG. 1A, a detection device with an illumination device 120 has a detection device 1 (light detection device), an illumination device 121, and a cover glass 122. The illumination device 121, the detection device 1, and the cover glass 122 are stacked in this order in a direction perpendicular to the surface of the detection device 1.

[0012] The illumination device 121 has a light irradiation surface 121a that emits light, and emits light L1 from the light irradiation surface 121a toward the detection device 1. The illumination device 121 is a backlight. The illumination device 121 may be, for example, a so-called side-light type backlight that has a light guide plate provided at a position corresponding to the detection area AA and a plurality of light sources lined up at one end or both ends of the light guide plate. For example, a light-emitting diode (LED) that emits light of a predetermined color is used as the light source. The illumination device 121 may also be a so-called direct-type backlight that has a light source (for example, an LED) provided directly below the detection area AA. The illumination device 121 is not limited to a backlight, and may be provided to the side or above the detection device 1, and may emit light L1 from the side or above the finger Fg.

[0013] The detection device 1 is disposed opposite the light irradiation surface 121a of the illumination device 121. Light L1 emitted from the illumination device 121 passes through the detection device 1 and the cover glass 122. The detection device 1 detects light L2 reflected by or transmitted through the subject's finger Fg, wrist, etc., thereby detecting information about the living body inside the finger Fg, wrist, etc. (hereinafter also referred to as "biometric information"). The color of the light L1 from the illumination device 121 may be varied depending on the biological information to be detected (for example, pulse wave).

[0014] The cover glass 122 is a member for protecting the detection device 1 and the illumination device 121, and covers the detection device 1 and the illumination device 121. The cover glass 122 is, for example, a glass substrate. Note that the cover glass 122 is not limited to a glass substrate, and may be a resin substrate or the like. Also, the cover glass 122 may not be provided. In this case, a protective layer is provided on the surface of the detection device 1, and the subject's finger Fg, wrist, etc. come into contact with the protective layer of the detection device 1.

[0015] 1B is a cross-sectional view showing a schematic cross-sectional configuration of a detection device with an illumination device according to a modified example. As shown in FIG. 1B, detection device with an illumination device 120A has detection device 1, illumination device 121, and cover glass 122 stacked in this order in a direction perpendicular to the surface of detection device 1. In this modified example, a display panel such as an organic EL display panel can be used as illumination device 121.

[0016] Light L1 emitted from the illumination device 121 passes through the cover glass 122, and is then reflected by or passes through the subject's finger Fg, wrist, etc. Light L2 reflected by or passes through the subject's finger Fg, wrist, etc. passes through the cover glass 122 and then passes through the illumination device 121. The detection device 1 receives the light L2 that has passed through the illumination device 121, thereby being able to detect biological information (e.g., pulse wave) that is the detection target.

[0017] Fig. 2 is a plan view showing a detection device according to a comparative example. In the comparative example shown in Fig. 2, the detection device has a sensor unit 3, a power supply circuit 4, a drive circuit 6, and a detection circuit 5 on a substrate 2.

[0018] The substrate 2 has a detection area AA and a peripheral area GA. The detection area AA has a plurality of divided areas 30 arranged in a matrix. The detection area AA is an area that overlaps with the plurality of divided areas 30 of the sensor unit 3. In the comparative example shown in FIG. 2, the detection area AA is divided into M columns and N rows of divided areas 30, in which M columns of divided areas 30 are arranged in the X direction (first direction) and N rows of divided areas 30 are arranged in the Y direction (second direction).

[0019] The peripheral area GA is an area outside the detection area AA and does not overlap with the divided area 30. In other words, the peripheral area GA is an area between the outer periphery of the detection area AA and the edge of the substrate 2. Fig. 2 shows an example in which a power supply circuit 4, a drive circuit 6, and a detection circuit 5 are provided in the peripheral area GA.

[0020] In the comparative example shown in FIG. 2, each divided region 30 is provided with a photosensor PD (see FIG. 3). In the present disclosure, the photosensor PD provided in each divided region 30 is an organic photodiode (OPD). An organic semiconductor layer of the photosensor PD is provided on the substrate 2. The organic semiconductor layer uses a material that is sensitive to near-infrared light (for example, light with a wavelength of 850 nm). Each divided region 30 is a region where the organic semiconductor layer of each photosensor PD is provided. The organic semiconductor layer of each photosensor PD is insulated by a bank layer (insulating layer). In other words, the organic semiconductor layer of each photosensor PD is provided in a region surrounded by the bank layer.

[0021] The power supply circuit 4 is a circuit that supplies various potentials and various power supply voltages to be applied to the divided regions 30. The various potentials and various power supply voltages that are applied to the divided regions 30 will be explained in the configuration of the divided regions 30, which will be described later.

[0022] The drive circuit 6 is a circuit that outputs various control signals, such as a read control signal, to the divided regions 30 and controls the operation of the divided regions 30. The various control signals, such as a read control signal, that are output to the divided regions 30 will be described later in the configuration of the divided regions 30.

[0023] The detection circuit 5 is a circuit that performs a predetermined detection process based on the signal output from the divided region 30. The detection circuit 5, for example, performs AD conversion on the signal output from the divided region 30 and outputs the converted signal to a downstream processing device (not shown) or the like.

[0024] 3 is a diagram showing an example of the configuration of each divided region of a detection device according to a comparative example, and a connection example with a detection circuit 5. In FIG. 3, an example of the configuration of divided regions 30 of m columns and n-1 rows and m columns and n rows and a connection example with a detection circuit 5 are shown.

[0025] 3, each divided region 30 is provided with a photosensor PD, a readout transistor Mrd, and a reset transistor Mrst. A power supply potential PVSS and a reset potential VRST are supplied to each divided region 30 from a power supply circuit 4. The power supply potential PVSS is set to, for example, 0.75 [V]. The reset potential VRST is set to, for example, 2.75 [V].

[0026] Detection Circuit 5 A constant current source for supplying a bias current Ib to the read transistor Mrd is connected to the detection circuit 5. This makes it possible to detect the output of each divided region 30 via the read transistor Mrd during the read period Prd (see FIG. 4). This constant current source may be provided in the detection circuit 5 or in the peripheral region GA of the substrate 2.

[0027] The anode of the photosensor PD is supplied with a power supply potential PVSS. The cathode of the photosensor PD is supplied with a reset potential VRST via the reset transistor Mrst during the reset period Prst (see FIG. 4). This causes the photosensor PD to be reverse biased (2.0 [V]).

[0028] The operation of the configuration according to the comparative example will be described below with reference to Fig. 4, which is a timing chart showing an example of the operation of the detection device according to the comparative example.

[0029] 4, in the configuration according to the comparative example, the detection device has a reset period Prst, an exposure period Pch, and a readout period Prd within one frame period 1F of the detection operation. The power supply circuit 4 supplies the power supply potential PVSS to the anode of the photosensor PD throughout the reset period Prst, the exposure period Pch, and the readout period Prd.

[0030] During the reset period Prst, the drive circuit 6 sequentially outputs the reset signal RST <n>to a high potential "H" (hereinafter also referred to as "H control"). As a result, the reset transistor Mrst in each divided region 30 is controlled to be on, a reset potential VRST (e.g., 2.75 [V]) is applied to the cathode of the photosensor PD via the reset transistor Mrst, and the photosensor PD is reverse biased (2.0 [V]). At this time, a charge corresponding to the reverse bias voltage is stored in the photosensor PD.

[0031] Reset signal RST <n>is controlled to a low potential "L" (hereinafter also referred to as "L control"), the reset transistor Mrst of each divided region 30 is controlled to be off, and an exposure period Pch for each photosensor PD begins. During this exposure period Pch, a reverse current flows through the photosensor PD, gradually reducing the charge stored in the photosensor PD during the reset period Prst. The reverse current flowing during the exposure period Pch varies depending on the amount of light incident on the photosensor PD.

[0032] Thereafter, the drive circuit 6 sequentially outputs the read signal RD during the read period Prd. <n>of High voltage to control (H control) As a result, the readout transistor Mrd in each divided region 30 is turned on, a bias current Ib flows, and a voltage corresponding to the charge stored in the photosensor PD is detected by the detection circuit 5. The period from when the reset transistor Mrst in each divided region 30 is turned off to when the readout transistor Mrd is turned on is called the "effective exposure period."

[0033] By repeatedly executing the reset period Prst, exposure period Pch, and readout period Prd described above over a plurality of frames, it is possible to acquire time-varying biological information such as a pulse wave.

[0034] Here, if variations occur in the organic semiconductor layer of the OPD (photo sensor PD), variations may occur in the reverse bias characteristics, which may result in a decrease in detection accuracy. Below, the diode characteristics of the photo sensor PD when variations occur in the organic semiconductor layer will be described with reference to Figures 5, 6A, and 6B.

[0035] Fig. 5 is a diagram showing an example of the diode characteristics of an optical sensor. In Fig. 5, the horizontal axis represents current, and the vertical axis represents voltage. In Fig. 5, the solid line represents the diode characteristics under normal conditions, and the dashed line represents an example of characteristic changes due to characteristic variations in the OPD. In Fig. 5, the positive current direction represents when a forward current flows through the diode of the optical sensor PD, and the negative current direction represents when a reverse current flows through the diode of the optical sensor PD.

[0036] 6A and 6B are diagrams showing examples of visualization of the output levels in each divided region in the detection region. Fig. 6A shows an example of visualization of detection region AA immediately after the start of detection operation, and Fig. 6B shows an example of visualization of detection region AA 15 minutes after the start of detection operation. In the examples shown in Fig. 6A and 6B, areas where the output level has become abnormal appear as bright spots.

[0037] Variations in the organic semiconductor layer of the OPD may cause the reverse bias characteristics of the OPD to change over time, as shown by the dashed line in Fig. 5. This may cause variations in the reverse current flowing through the photosensors PD of each divided region 30 during the exposure period Pch (effective exposure period), resulting in reduced detection accuracy.

[0038] In particular, in a configuration that acquires time-varying biological information such as pulse waves, observation must be performed over a relatively long period of time, and in such a configuration, the accuracy deteriorates significantly due to the change in the reverse bias characteristics of the OPD over time, as shown in Figure 6B.

[0039] Furthermore, when acquiring time-varying data such as pulse waves with high accuracy, detection must be performed at a high frame rate.

[0040] The change over time in the variation in the reverse bias characteristics of the OPD caused by the variation in the organic semiconductor layer can be eliminated by forward-biasing the photosensor PD to flow a forward bias current and return the OPD characteristics to their initial state. In this disclosure, this operation of returning the OPD characteristics to their initial state is referred to as a "refresh operation." Below, a configuration example and an operation example of the detection device 1 according to the embodiment will be described with reference to FIGS. 7 to 9.

[0041] Fig. 7 is a plan view showing a detection device according to an embodiment. Fig. 8 is a diagram showing an example of the configuration of each divided region of the detection device according to an embodiment and a connection to a detection circuit. Fig. 9 is a timing chart showing an example of the operation of the detection device according to an embodiment. In the following description, explanations of components that are the same as those in the comparative example described above will be omitted.

[0042] In the configuration of the detection device 1 according to the embodiment shown in FIG. 7, the detection area AA is divided into M columns and 2N rows in which M first divided areas 30_1 are arranged in the X direction (first direction), M second divided areas 30_2 are arranged in the X direction (first direction), and N first divided areas 30_1 and N second divided areas 30_2 are arranged alternately in the Y direction (second direction).

[0043] In addition, in the detection device 1 according to the embodiment, as shown in FIG. 7, an inverted L-shaped first divided region 30_1 in an odd-numbered row (2n-1 row) and an L-shaped second divided region 30_2 in an even-numbered row (2n row) adjacent to each other are combined so as to overlap partially in the X direction (first direction).

[0044] 8, the first division region 30_1 is provided with a first photosensor PD1, a readout transistor Mrd1, and a reset transistor Mrst1 (second transistor). A power supply potential PVSS (first potential) and a reset potential VRST (third potential) are supplied to the first division region 30_1 from the power supply circuit 4. The power supply potential PVSS (first potential) is set to, for example, 0.75 [V]. The reset potential VRST (third potential) is set to, for example, 2.75 [V].

[0045] 8, the first divided region 30_1 of the detection device 1 according to the embodiment is provided with a refresh transistor Mref1 (first transistor) in addition to the configuration of the comparative example shown in FIG. 3. A refresh potential VREF is supplied to the first divided region 30_1 from the power supply circuit 4. The refresh potential VREF is set to, for example, −1.25 [V].

[0046] 8, the second division region 30_2 is provided with a second photosensor PD2, a readout transistor Mrd2, and a reset transistor Mrst2 (fourth transistor). A power supply potential PVSS (first potential) and a reset potential VRST (third potential) are supplied from the power supply circuit 4 to the second division region 30_2.

[0047] 8, the second divided region 30_2 of the detection device 1 according to the embodiment is provided with a refresh transistor Mref2 (third transistor) in addition to the configuration of the comparative example shown in Fig. 3. A refresh potential VREF is supplied to the second divided region 30_2 from the power supply circuit 4.

[0048] The cathodes of the first optical sensor PD1 and the second optical sensor PD2 are supplied with a current during the refresh period. Pref<2n-1> , Pref<2n> 9, a refresh potential (second potential) VREF is supplied via refresh transistors Mref1 and Mref2, which causes the first photosensor PD1 and the second photosensor PD2 to be forward biased (2.0 [V]).

[0049] 9, the detection device 1 according to the embodiment has a reset period Prst<2n-1>, an exposure period Pch<2n-1>, and a readout period Prd<2n-1> for the first photosensors PD1 in each of the odd-numbered (2n-1) first divided regions 30_1 during an odd-numbered frame period 1F_odd (first period) of the detection operation. Also, the detection device 1 according to the embodiment has a refresh period Pref<2n> for the second photosensors PD in each of the even-numbered (2n) second divided regions 30_2 during an odd-numbered frame period 1F_odd (first period) of the detection operation.

[0050] The drive circuit 6 sequentially outputs the reset signal RST<2n-1> during the reset period Prst<2n-1>. High voltage to control (H control) As a result, the reset transistor Mrst1 (second transistor) of each first divided region 30_1 in the odd-numbered rows (2n-1 rows) is turned on, a reset potential VRST (e.g., 2.75 [V]) is applied to the cathode of the first photosensor PD1 in each first divided region 30_1 in the odd-numbered rows (2n-1 rows) via the reset transistor Mrst1 (second transistor), and the first photosensor PD1 in each first divided region 30_1 in the odd-numbered rows (2n-1 rows) is reverse-biased (2.0 [V]). At this time, the first photosensor PD1 in each first divided region 30_1 in the odd-numbered rows (2n-1 rows) is charged with a charge corresponding to the reverse bias voltage.

[0051] Furthermore, the drive circuit 6 sequentially outputs the refresh signal REF<2n> during the refresh period Pref<2n>. High voltage to control (H control) As a result, the refresh transistor Mref2 (third transistor) of each second division region 30_2 in the even-numbered rows (2n rows) is turned on, a refresh potential VREF (e.g., −1.25 [V]) is applied to the cathode of the second photosensor PD2 in each second division region 30_2 in the even-numbered rows (2n rows) via the refresh transistor Mref2 (third transistor), and the second photosensor PD2 in each second division region 30_2 in the even-numbered rows (2n rows) is forward biased (2.0 [V]). This allows the reverse bias characteristics of the second photosensor PD2 in each second division region 30_2 in the even-numbered rows (2n rows) to be returned to their initial state. Note that the reset period Prst<2n−1> of the odd-numbered rows (2n−1 rows) and the refresh period Pref<2n> of the even-numbered rows (2n rows) overlap each other.

[0052] Reset signal RST<2n-1> Low potential When controlled by (L control) , the reset transistor Mrst1 (second transistor) of each first divided region 30_1 in the odd-numbered rows (2n-1 rows) is controlled to be turned off, and an exposure period Pch<2n-1> is started for each first photosensor PD1 in each first divided region 30_1 in the odd-numbered rows (2n-1 rows). During this exposure period Pch<2n-1>, a reverse current flows through the first photosensor PD1 in each first divided region 30_1 in the odd-numbered rows (2n-1 rows), so that the electric charge stored in the first photosensor PD1 in each first divided region 30_1 in the odd-numbered rows (2n-1 rows) during the reset period Prst<2n-1> gradually decreases.

[0053] Thereafter, the drive circuit 6 sequentially outputs the read signal RD<2n-1> during the read period Prd<2n-1>. High voltage to control (H control) As a result, the readout transistor Mrd1 in each first division region 30_1 in the odd-numbered rows (2n-1 rows) is turned on, a bias current Ib flows, and a voltage corresponding to the charge stored in the first photosensor PD1 in each first division region 30_1 in the odd-numbered rows (2n-1 rows) is detected by the detection circuit 5.

[0054] 9, the detection device 1 according to the embodiment has a reset period Prst<2n>, an exposure period Pch<2n>, and a readout period Prd<2n> for the second photosensors PD2 of each of the second divided regions 30_2 in the even-numbered rows (2n rows) during an even-numbered frame period 1F_even (second period) in the detection operation. 1st divided area 30_1 of First optical sensor PD1 The refresh period Pref<2n-1> is

[0055] The drive circuit 6 sequentially outputs the reset signal RST<2n> during the reset period Prst<2n>. High voltage to control (H control) As a result, the reset transistor Mrst2 (fourth transistor) of each second division region 30_2 in the even-numbered rows (2n rows) is turned on, a reset potential VRST (third potential) is applied to the cathode of the second photosensor PD2 in each second division region 30_2 in the even-numbered rows (2n rows) via the reset transistor Mrst2 (fourth transistor), and the second photosensor PD2 in each second division region 30_2 in the even-numbered rows (2n rows) is reverse-biased (2.0 [V]). At this time, the second photosensor PD2 in each second division region 30_2 in the even-numbered rows (2n rows) is charged with a charge corresponding to the reverse bias voltage.

[0056] Furthermore, the drive circuit 6 sequentially outputs the refresh signal REF<2n-1> during the refresh period Pref<2n-1>. To high voltage Control (H potential) As a result, the refresh transistor Mref1 (first transistor) of each first division region 30_1 in the odd-numbered rows (2n-1 rows) is turned on, a refresh potential VREF (e.g., -1.25 [V]) is applied to the cathode of the first photosensor PD1 in each first division region 30_1 in the odd-numbered rows (2n-1 rows) via the refresh transistor Mref (first transistor), and the first photosensor PD1 in each first division region 30_1 in the odd-numbered rows (2n-1 rows) is forward biased (2.0 [V]). This allows the reverse bias characteristics of the first photosensor PD1 in each first division region 30_1 in the odd-numbered rows (2n-1 rows) to be returned to their initial state. Note that the reset period Prst<2n> of the even-numbered rows (2n rows) and the refresh period Pref<2n-1> of the odd-numbered rows (2n-1 rows) overlap each other.

[0057] The reset signal RST<2n> To low potential When controlled (L control) , the reset transistor Mrst2 (fourth transistor) of each second divided region 30_2 in the even-numbered rows (2n rows) is controlled to be turned off, and an exposure period Pch<2n> is started for each second photosensor PD2 in each second divided region 30_2 in the even-numbered rows (2n rows). During this exposure period Pch<2n>, a reverse current flows through the second photosensor PD2 in each second divided region 30_2 in the even-numbered rows (2n rows), so that the electric charge stored in the second photosensor PD2 in each second divided region 30_2 in the even-numbered rows (2n rows) during the reset period Prst<2n> gradually decreases.

[0058] Thereafter, the drive circuit 6 sequentially outputs the read signal RD<2n> in the read period Prd<2n>. To high voltage Control (H control) This allows even number The read transistor of each second division region 30_2 in the row (2n rows) Mrd2 is turned on to cause the bias current Ib to flow, and the detection circuit 5 detects a voltage corresponding to the charge stored in the second photosensor PD2 of each second divided region 30_2 in the even-numbered rows (2n rows).

[0059] By alternately and repeatedly executing the odd-numbered frame period 1F_odd (first period) and the even-numbered frame period 1F_even (second period), the detection operation of the first optical sensor PD1 in each of the odd-numbered (2n-1) first divided regions 30_1 and the detection operation of the second optical sensor PD2 in each of the even-numbered (2n) second divided regions 30_2 are alternately executed. Furthermore, the refresh operation of the second optical sensor PD2 in each of the even-numbered (2n) second divided regions 30_2 is executed during the odd-numbered frame period 1F_odd (first period) when the detection operation of the first optical sensor PD1 in each of the odd-numbered (2n-1) first divided regions 30_1 is being executed, and the refresh operation of the first optical sensor PD1 in each of the odd-numbered (2n-1) first divided regions 30_1 is executed during the even-numbered (2n-1) frame period 1F_even (second period) when the detection operation of the second optical sensor PD2 in each of the even-numbered (2n) second divided regions 30_2 is being executed. This makes it possible to acquire time-varying biological information such as pulse waves with high accuracy without reducing the frame rate.

[0060] The division example within the detection area AA is not limited to the embodiment in which an inverted L-shaped first divided area 30_1 in odd-numbered rows (2n-1 rows) and an L-shaped second divided area 30_2 in even-numbered rows (2n rows) are combined so as to partially overlap in the X direction (first direction) as shown in Fig. 7. In the following explanations of each modification, explanations of components that are the same as those in the above-described embodiment will be omitted.

[0061] Fig. 10 is a plan view showing a detection device according to a first modified example of the embodiment. In the configuration of the detection device 1a according to the first modified example of the embodiment shown in Fig. 10, a rectangular first divided region 30_1 and a rectangular second divided region 30_2 are arranged in a matrix in a detection area AA, similar to the comparative example shown in Fig. 2.

[0062] FIG. 11 is a plan view showing a detection device according to a second modification of the embodiment. In the configuration of the detection device 1b according to the second modification of the embodiment, as shown in FIG. 11, a diamond-shaped first divided region 30_1 and a diamond-shaped second divided region 30_2 are arranged in a staggered pattern within a detection region AA. In other words, within the detection region AA, the position of the second divided region 30_2 in the X direction (first direction) is shifted relative to the position of the first divided region 30_1 in the X direction (first direction). In this configuration, similar to the configuration shown in FIG. 7, the first divided region 30_1 in an odd-numbered row (2n-1 row) and the second divided region 30_2 in an even-numbered row (2n row) adjacent to each other are combined so as to partially overlap in the X direction (first direction). Furthermore, the position of the second divided region 30_2 in the Y direction (second direction) is shifted relative to the position of the first divided region 30_1 in the Y direction (second direction).

[0063] Furthermore, the above-described embodiments can be combined with the respective components as appropriate. Furthermore, other effects and advantages brought about by the aspects described in the present embodiments that are obvious from the description in this specification or that can be conceived by a person skilled in the art are naturally understood to be brought about by the present invention. [Explanation of symbols]

[0064] 1, 1a, 1b Detection device 2 boards 3 Sensor section 4 Power circuit 5 Detection circuit 6 Drive circuit 30 divided areas 30_1 Split area (first split area) 30_2 divided area (second divided area) AA detection area GA peripheral area Mrd, Mrd1, Mrd2 readout transistors Mrst Reset Transistor Mrst1 Reset transistor (second transistor) Mrst2 reset transistor (fourth transistor) Mref refresh transistor Mref1 Refresh transistor (first transistor) Mref2 Refresh transistor (third transistor) Pch exposure period PD light sensor Prd read period Pref Refresh Period Prst Reset Period PVSS Power supply potential (first potential) RD read signal RST Reset signal REF Refresh signal VREF Refresh potential (second potential) VRST Reset potential (third potential)< / n> < / n> < / n>

Claims

1. a sensor unit having a first photodiode and a second photodiode; a detection circuit that alternately detects the output of the first photodiode and the output of the second photodiode; Equipped with a first potential is supplied to the anodes of the first photodiode and the second photodiode; a first period during which the output of the first photodiode is detected; a second period during which the output of the second photodiode is detected; and The first period of time is a refresh period in which a second potential lower than the first potential is supplied to the cathode of the second photodiode; an exposure period during which the first photodiode is exposed; a readout period in which the charge stored in the first photodiode is read out; and The second period is a refresh period in which the second potential is supplied to the cathode of the first photodiode; an exposure period during which the second photodiode is exposed; a readout period in which the charge stored in the second photodiode is read out; having Detection device.

2. a third potential higher than the first potential is supplied to the cathode of the first photodiode during a refresh period of the first period; During a refresh period of the second period, the third potential is supplied to the cathode of the second photodiode. The detection device according to claim 1 .

3. The sensor unit a detection region including a first divided region in which the first photodiode is provided and a second divided region in which the second photodiode is provided; The first divided region and the second divided region are adjacent to each other within the detection region. The detection device according to claim 2 .

4. The first divided region is a first transistor that supplies the second potential to the cathode of the first photodiode; a second transistor that supplies the third potential to the cathode of the first photodiode; is established, The second divided region is a third transistor that supplies the second potential to the cathode of the second photodiode; a fourth transistor that supplies the third potential to the cathode of the second photodiode; are provided, The detection device according to claim 3 .

5. When the first transistor is turned on, the fourth transistor is turned on; When the third transistor is controlled to be on, the second transistor is controlled to be on. The detection device according to claim 4 .

6. the sensor unit includes a plurality of first divided regions and a plurality of second divided regions, a plurality of the first divided regions are arranged in a first direction, a plurality of the second divided regions are arranged in the first direction, The first division regions and the second division regions are alternately arranged in a second direction different from the first direction.

6. A detection device according to any one of claims 3 to 5.

7. the first division region and the second division region adjacent to each other in the second direction are provided to partially overlap each other in the first direction; The detection device according to claim 6.

8. the sensor unit includes a plurality of first divided regions and a plurality of second divided regions, a plurality of the first divided regions are arranged in a first direction, a plurality of the second divided regions are arranged in the first direction, Within the detection area, the second divided area is disposed so as to be shifted in position in the first direction relative to the first divided area.

6. A detection device according to any one of claims 3 to 5.

9. the first photodiode and the second photodiode are organic photodiodes.

9. A detection device according to any one of claims 3 to 8.

10. an organic semiconductor layer is provided in the first dividing region and the second dividing region; The detection device according to claim 9.

11. the organic semiconductor layer in the first dividing region and the organic semiconductor layer in the second dividing region are insulated from each other; The detection device according to claim 10.

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