DETECTION DEVICE
A detection device includes a sensor unit that has a detection area divided into a plurality of partial detection areas, a control circuit that has a first mode of acquiring data for each of the partial detection areas based on a detection value acquired from the partial detection area and a second mode of selecting the partial detection areas in which a signal strength of the data acquired in the first mode is relatively higher among the partial detection areas, and acquiring biometric data of an object to be detected based on a detection value acquired by coupling the selected partial detection areas in parallel, and an amplifying circuit configured to receive the detection value acquired in the second mode.
1 . A detection device comprising:
a sensor unit that has a detection area divided into a plurality of partial detection areas;
a control circuit that has a first mode of acquiring data for each of the partial detection areas based on a detection value acquired from the partial detection area and a second mode of selecting the partial detection areas in which a signal strength of the data acquired in the first mode is relatively higher among the partial detection areas, and acquiring biometric data of an object to be detected based on a detection value acquired by coupling the selected partial detection areas in parallel; and
an amplifying circuit configured to receive the detection value acquired in the second mode.
2 . The detection device according to claim 1 , wherein the control circuit is configured to select the partial detection areas in which a ratio of an alternating-current component to a direct-current component of the data acquired in the first mode is equal to or higher than a predetermined value in the second mode.
3 . The detection device according to claim 1 , wherein the control circuit is configured to select the partial detection areas in which a ratio of an alternating-current component to a direct-current component of the data acquired in the first mode is included in a predetermined number of highest-ranked ratios among the partial detection areas in the second mode.
4 . The detection device according to claim 1 , wherein the control circuit is configured to sequentially acquire the detection value for each of the partial detection areas in the first mode.
5 . The detection device according to claim 4 , wherein
the sensor unit comprises a shift register circuit in which flip-flop circuits provided in the respective partial detection areas are coupled in a cascade arrangement, and
the control circuit is configured to write a set value indicating a selection state in the second mode to each of the flip-flop circuits.
6 . The detection device according to claim 1 , wherein
the partial detection areas are provided in a matrix having a row-column configuration in the detection area,
the sensor unit comprises a storage circuit provided in each of the partial detection areas, and
the control circuit is configured to write a set value indicating a selection state in the second mode to the storage circuit.
7 . The detection device according to claim 6 , wherein
the sensor unit comprises:
a first drive circuit comprising a shift register circuit in which a plurality of flip-flop circuits arranged in a row direction are coupled in a cascade arrangement; and
a second drive circuit comprising a shift register circuit in which a plurality of flip-flop circuits arranged in a column direction are coupled in a cascade arrangement,
the flip-flop circuits of the first drive circuit are coupled to the respective storage circuits provided in the partial detection areas arranged in the column direction,
the flip-flop circuits of the second drive circuit are coupled to the respective storage circuits provided in the partial detection areas arranged in the row direction, and
the control circuit is configured to write the set value indicating the selection state in the second mode to the storage circuit in the partial detection area selected by the second drive circuit via the first drive circuit.
8 . The detection device according to claim 6 , wherein
the detection area is divided into a plurality of data acquisition areas, in each of which the partial detection areas are arranged in a row direction, and
a plurality of the amplifying circuits are provided correspondingly to the data acquisition areas.
9 . The detection device according to claim 1 , further comprising a light source configured to emit light to the detection area, wherein
the sensor unit comprises a plurality of optical sensors provided in the respective partial detection areas, and
the control circuit has a reset period to apply a reference potential to the optical sensors, an exposure period to expose the optical sensors to the light, and a read period to read electric charges that have charged the optical sensors.
10 . The detection device according to claim 9 , wherein the control circuit is configured to apply the reference potential to the optical sensors in the partial detection areas that are not selected in the second mode.
11 . The detection device according to claim 9 , wherein the control circuit is capable of changing a negative feedback capacitor of the amplifying circuit according to a number of the parallelly coupled partial detection areas in the second mode.
12 . The detection device according to claim 9 , capable of changing an amount of light of the light source according to a number of the parallelly coupled partial detection areas in the second mode.
13 . The detection device according to claim 9 , wherein the control circuit is capable of changing the exposure period according to a number of the parallelly coupled partial detection areas in the second mode.
14 . The detection device according to claim 9 , wherein
the light source comprises:
a first light source configured to emit first light to the detection area; and
a second light source configured to emit second light having a different wavelength from that of the first light to the detection area, and
the detection value acquired in the second mode comprises:
a first detection value acquired by the emission of the first light; and
a second detection value acquired by the emission of the second light.
15 . The detection device according to claim 14 , wherein one of the first light and the second light is infrared light.
16 . The detection device according to claim 15 , wherein one of the first light and the second light is red light.
17 . The detection device according to claim 16 , wherein the control circuit is configured to calculate a blood oxygen saturation level based on the first detection value and the second detection value that have been acquired in the second mode.
18 . The detection device according to claim 9 , wherein the optical sensors are organic photodiodes.