Detection device

Abstract

A detection device that absorbs variations between individual devices. [Solution] The detection device comprises a plurality of light sensors each having a photodiode, a reset transistor that applies a reset potential to the cathode, a source follower transistor that outputs a signal corresponding to the potential generated by the photodiode, and a readout transistor for the output signal; a sensor panel having a detection area in which the light sensors are arranged in a planar manner; a light source that irradiates the object to be detected between the sensor panel and the light source; a detection circuit that acquires a potential corresponding to the bias current of the readout transistor; and a control circuit for the sensor panel, the light source, and the detection circuit. When there is no object to be detected, the control circuit controls the reset transistor and the readout transistor to be turned ON and performs an initial setting process to adjust at least one of the set values ​​of the reset potential and the bias current so that the input potential acquired by the detection circuit via the signal transmission path between the light sensor and the detection circuit falls within a predetermined target setting range.

Claims

1. Photodiodes and A reset transistor that applies a reset potential to the cathode of the aforementioned photodiode, A source follower transistor that outputs a signal corresponding to the potential generated by the photodiode, A readout transistor that reads the output signal of the source follower transistor, Multiple light sensors each equipped with, A sensor panel having a detection area in which multiple optical sensors are arranged in a planar manner, A light source is provided between the sensor panel and the object to be detected, A detection circuit that acquires a potential corresponding to the bias current flowing through the readout transistor, The sensor panel, the light source, and the control circuit for controlling the detection circuit, Equipped with, The aforementioned control circuit is With no object to be detected between the sensor panel and the light source, the reset transistor and the read transistor are controlled to be turned ON, and an initial setup process is performed to adjust at least one of the reset potential setting value and the bias current setting value so that the input potential acquired by the detection circuit via the signal transmission path between the light sensor and the detection circuit falls within a predetermined target setting range. Detection device.

2. The target setting range is a range of 80% to 90% of the upper limit of the input value of the detection circuit. The detection device according to claim 1.

3. The aforementioned control circuit is In the initial setup process, the reset potential setting value and the reference potential setting value applied to the anode of the photodiode are adjusted so that the potential difference across the photodiode becomes constant. The detection device according to claim 1 or 2.

4. The aforementioned control circuit is In the initial setup process, at least one of the reset potential setting value and the bias current setting value is adjusted so that the average value of the multiple input potentials corresponding to the multiple optical sensors falls within a predetermined target setting range. The detection device according to claim 1 or 2.

5. The aforementioned control circuit is In the initial setup process, at least one of the reset potential setting value and the bias current setting value is adjusted so that the average value of multiple input potentials corresponding to a portion of the optical sensors included in the detection region falls within a predetermined target setting range. The detection device according to claim 1 or 2.

6. The sensor panel has a plurality of light sensors arranged in a matrix in the detection area along a first direction and a second direction intersecting the first direction. The aforementioned control circuit is In the initial setup process, at least one of the reset potential setting value and the bias current setting value is adjusted so that the average value of multiple input potentials corresponding to multiple photons located at predetermined intervals in the first and second directions, respectively, among the photons included in the detection region, falls within a predetermined target setting range. The detection device according to claim 1 or 2.

7. The sensor panel has a detection area that is divided into multiple sub-regions. The aforementioned control circuit is In the initial setup process, at least one of the reset potential setting value and the bias current setting value is adjusted so that the average value of multiple input potentials corresponding to multiple photons included in a portion of the multiple divided regions falls within a predetermined target setting range. The detection device according to claim 1 or 2.

8. The light source irradiates the object to be detected with multiple different colored lights in a time-division manner. The aforementioned control circuit is In the initial setup process, at least one of the reset potential setting value and the bias current setting value is adjusted for each light emission color of the light source. The detection device according to claim 1 or 2.

9. The aforementioned initial setup process is, A first process of reducing the set value of the reset potential until the input potential falls below the upper limit of the input of the detection circuit, A second process involves increasing the set value of the reset potential until the input potential exceeds the lower limit of the input of the detection circuit. If the input potential exceeds the lower input limit and is less than the upper input limit, a third process is performed to calculate the set value of the reset potential by adding the difference between the input potential and a predetermined value within the target setting range to the reset potential. including, The detection device according to claim 1 or 2.

10. The aforementioned initial setup process is, A first process of reducing the bias current setting value until the input potential falls below the input upper limit of the detection circuit, A second process involves increasing the set value of the bias current until the input potential exceeds the lower limit of the input of the detection circuit. A third process to calculate the bias current setting value such that, when the input potential exceeds the lower input limit and is less than the upper input limit, the value obtained by subtracting the threshold voltage of the source follower transistor and the voltage drop corresponding to the resistance component of the signal transmission path from the reset potential is a predetermined value within the target setting range, including, The detection device according to claim 1 or 2.

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