PHOTOELECTRIC SPHYGMOGRAPH MEASUREMENT DEVICE

• US 20110257534A1
• Filed: 06/27/2011
• Published: 10/20/2011
• Est. Priority Date: 01/29/2009
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: SANO, Satoshi, Nakano, Yasuhiko, Yamaji, Takayuki
• Granted Patent: US 9,782,127 B2
• Time in Patent Office: Days
• US Class Current: 600/479
• CPC Class Codes: A61B 2560/0209 adapted for power saving
• CPC Class Codes: A61B 5/02427 Details of sensor
• CPC Class Codes: A61B 5/6816 Ear lobe

Abstract

A photoelectric sphygmograph measurement device includes a light emitting part emitting light pulses, a light receiving part having a light receiving element that receives the light pulses and producing a corresponding output signal, and a control part driving the light emitting part to emit the light pulses and performing a pulse wave measurement by using the output signal. The control part drives the light emitting part so that a charge accumulated in the light emitting element converges on a predetermined amount in a case where the charge accumulated in the light receiving element decreases to the predetermined amount or less during a time when driving of the light emitting part is stopped and/or in a case where the light receiving element changes to a first state in which the light receiving element is capable of receiving the light pulses from a second state in which the light receiving element is not capable of receiving the light pulses.

Claims

1. A photoelectric sphygmograph measurement device comprising:

a light emitting part configured to emit light pulses;

a light receiving part configured to have a light receiving element that receives the light pulses emitted by the light emitting part and to produce an output signal corresponding to the light pulses received by the light receiving element; and

a control part configured to drive the light emitting part to emit the light pulses and perform a pulse wave measurement on the basis of the output signal of the light receiving part,

the control part driving the light emitting part so that a charge accumulated in the light emitting element converges on a predetermined amount in a case where the charge accumulated in the light receiving element decreases to the predetermined amount or less during a time when driving of the light emitting part is stopped and/or in a case where the light receiving element changes to a first state in which the light receiving element is capable of receiving the light pulses from a second state in which the light receiving element is not capable of receiving the light pulses.

2. The photoelectric sphygmograph measurement device according to claim 1, wherein the control part causes the light emitting part to temporarily stop emitting the light pulses during a time when the light pulses emitted by the light emitting part are received directly by the light receiving element, and enables the light emitting part to emit the light pulses so that the charge converges on the predetermined amount in a case where the charge accumulated in the light receiving element decreases to the predetermined amount or less after the light emitting part is caused to temporarily stop emitting the light pulses.

3. The photoelectric sphygmograph measurement device according to claim 1, wherein in a case where the light receiving element changes to the second state from the first state, the control part emits the light pulses at intervals shorter than intervals for the pulse wave measurement to cause the charge accumulated in the light receiving element to converge on the predetermined amount.

4. The photoelectric sphygmograph measurement device according to claim 1, wherein the control circuit includes a peak hold type demodulation circuit configured to demodulate the output signal of the light receiving part, and an extraction circuit configured to extract an amplitude of a pulse wave signal output from the peak hold type demodulation circuit,

the control circuit identifying states of the light emitting part and the light receiving parts on the basis of the pulse wave signal from the peak hold type demodulation circuit and the amplitude of the pulse wave signal.