Sensor, sensor apparatus, and electronic device

Patent metadata

Field	Value
Publication number	US-10758134-B2
Application number	US-201515321045-A
Country	US
Kind code	B2
Filing date	May 27, 2015
Priority date	Jul 28, 2014
Publication date	Sep 1, 2020
Grant date	Sep 1, 2020

Abstract

A sensor that is capable of detecting a pulse of a user by using a proximity illumination sensor or a proximity sensor is provided. A proximity sensor ( 14 ) that includes a pulse detection function includes a count adjustment circuit ( 5 ) that performs adjustment such that a digital output value (ADCOUT 1 ) from an analog-digital conversion circuit ( 4 ) changes in accordance with each value of a distance at least in a prescribed range of the distance between a photodiode ( 2 ) and a detected object (a finger in the drawing) and a digital filter ( 6 ) for detecting a cycle of the digital output value (ADCOUT 1 ) from the analog-digital conversion circuit ( 4 ).

First claim

The invention claimed is:

1. A sensor that includes:
a first light-receiving element which receives infrared light; and
an analog-digital conversion circuit which converts an analog output value of the first light-receiving element to a digital output value,
wherein the analog-digital conversion circuit includes
a charging circuit that includes a capacity which stores a charge amount which corresponds to an input current from the first light-receiving element,
a comparator circuit that compares an output voltage of the charging circuit with a reference voltage,
a discharging circuit that discharges a predetermined charge amount at a time from the charge amount of the charging circuit based on an output value from the comparator circuit, and
a counter that outputs a discharge frequency of the discharging circuit as the digital output value, and

the sensor includes:
an adjustment circuit that (i) includes a second discharging circuit that discharges a predetermined charge amount in a measurement period and decides a discharge frequency in accordance with an offset value of the charge amount of the charging circuit and (ii) performs adjustment on the digital output value by offsetting the charge amount of the charging circuit, and

a digital filter that detects a cycle of the digital output value, and
the offset value of the charge amount of the charging circuit is a value that enables an adjustment such that the digital output value is not saturated in a prescribed range of a distance between the first light-receiving element and a detected object.

2. The sensor according to claim 1 , wherein the analog-digital conversion circuit includes a control circuit that outputs a control signal which controls discharge of the discharging circuit and includes the counter.

3. The sensor according to claim 1 , wherein the digital filter is configured with a low-pass filter and a high-pass filter.

4. The sensor according to claim 1 , wherein the cycle of the digital output value is detected by using a maximum value or a minimum value of the output value from the digital filter.

5. A sensor apparatus comprising:
the sensor according to claim 1 ; and
a light-emitting element that emits light which includes infrared light.

6. The sensor according to claim 1 , wherein the counter outputs the discharge frequency of the discharging circuit as the digital output value, the discharge frequency of the discharging circuit being decided in accordance with a charge amount obtained by applying the offset value to the charge amount of the charge circuit.

7. A sensor according to claim 1 , wherein the prescribed range is 1 mm to 1.6 mm.

8. An electronic device comprising:
a sensor that includes a first light-receiving element which receives infrared light and an analog-digital conversion circuit which converts an analog output value of the first light-receiving element to a digital output value,
wherein the analog-digital conversion circuit includes
a charging circuit that includes a capacity which stores a charge amount which corresponds to an input current from the first light-receiving element,
a comparator circuit that compares an output voltage of the charging circuit with a reference voltage,
a discharging circuit that discharges a predetermined charge amount at a time from the charge amount of the charging circuit based on an output value from the comparator circuit, and
a counter that outputs a discharge frequency of the discharging circuit as the digital output value,

the sensor includes
an adjustment circuit that (i) includes a second discharging circuit that discharges a predetermined charge amount in a measurement period and decides a discharge frequency in accordance with an offset value of the charge amount of the charging circuit and (ii) performs adjustment on the digital output value by offsetting the charge amount of the charging circuit,

the offset value of the charge amount of the charging circuit is a value that enables an adjustment such that the digital output value is not saturated in a prescribed range of a distance between the first light-receiving element and a detected object, and
a digital filter process is performed for the digital output value and a cycle thereof is detected.

9. The electronic device according to claim 8 , wherein the analog-digital conversion circuit includes a control circuit
that outputs a control signal which controls discharge of the discharging circuit and includes the counter.

10. The electronic device according to claim 8 , wherein the counter outputs the discharge frequency of the discharging circuit as the digital output value, the discharge frequency of the discharging circuit being decided in accordance with a charge amount obtained by applying the offset value to the charge amount of the charge circuit.

11. An electronic device according to claim 8 , wherein the prescribed range is 1 mm to 1.6 mm.

Assignees

• Sharp Kk

Inventors

• Inoue Takahiro
• Takahashi Nobuhiro

Classifications

• H03M1/52

  Input signal integrated with linear return to datum · CPC title

• A61B5/02438

  with portable devices, e.g. worn by the patient · CPC title

• A61B5/02433 Primary

  for infrared radiation · CPC title

• A61B5/725

  using specific filters therefor, e.g. Kalman or adaptive filters (specific diagnostics methods using using bioelectric or biomagnetic signals A61B5/316) · CPC title

• A61B5/6826

  Finger · CPC title