Pulse wave detection apparatus

• US 20080125664A1
• Filed: 11/13/2007
• Published: 05/29/2008
• Est. Priority Date: 11/27/2006
• Status: Abandoned Application

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Sakai, Kazuhiro, Nishii, Katsuyoshi
• Application Number:
  US11/979,969
• Publication Number:
  US 20080125664A1
• Time in Patent Office: Days
• US Class Current: 600/500
• CPC Class Codes: A61B 5/02444 Details of sensor A61B5/02427 takes precedence
• CPC Class Codes: A61B 5/14552 Details of sensors specially adapted therefor

Abstract

An optical pulse wave detection apparatus includes a light emitting element, a light receiving element, a first control unit, a second control unit, and a pulse wave detection unit. The first control unit obtains a first signal by causing the light emitting element to emit light of a first light quantity, and by causing the light receiving element to receive reflected light, which is reflected by a living organism, of the light of the first light quantity. The second control unit obtains a second signal by causing the light emitting element to emit the light of a second light quantity that is smaller than the first light quantity, and by causing the light receiving element to receive the reflected light of the light of the second light quantity. The pulse wave detection unit detects a pulse wave of the living organism based on the first and second signals.

Claims

1. An optical pulse wave detection apparatus comprising:

a light emitting element that emits light to a living organism;

a light receiving element that receives a reflected light of the light that is reflected by the living organism;

a first control unit for obtaining a first signal by causing the light emitting element to emit the light of a first light quantity, and by causing the light receiving element to receive the reflected light of the light of the first light quantity;

a second control unit for obtaining a second signal by causing the light emitting element to emit the light of a second light quantity that is smaller than the first light quantity, and by causing the light receiving element to receive the reflected light of the light of the second light quantity; and

a pulse wave detection unit for detecting a pulse wave of the living organism based on the first signal and the second signal.

2. The pulse wave detection apparatus according to claim 1, wherein the second light quantity is equal to or less than a half of the first light quantity.

3. The pulse wave detection apparatus according to claim 1, wherein the second light quantity is set at a level such that the reflected light that is received by the light receiving element has a light quantity other than a sensitivity deterioration range of the light receiving element.

4. The pulse wave detection apparatus according to claim 1, wherein an interval between a first timing for obtaining the first signal and a second timing for obtaining the second signal is set equal to or less than 3 msec.

5. The pulse wave detection apparatus according to claim 1, wherein a ratio of the first light quantity to the second light quantity is kept when both the first light quantity and the second light quantity are changed in accordance with a condition.

6. The pulse wave detection apparatus according to claim 1, wherein the pulse wave is detected based on a difference between the first signal and the second signal.

7. The pulse wave detection apparatus according to claim 6, wherein the pulse wave is detected by performing a frequency analysis using the difference.

8. The pulse wave detection apparatus according to claim 1, wherein the pulse wave is detected based on a difference between a result of a first frequency analysis using the first signal and a result of a second frequency analysis using the second signal.

9. The pulse wave detection apparatus according to claim 1, wherein a disturbance period is specified based on a result of frequency analysis using the second signal.

10. The pulse wave detection apparatus according to claim 9, wherein the pulse wave is detected by comparing the disturbance period with a result of a frequency analysis using a difference between the first signal and the second signal.

20. The pulse wave detection apparatus according to claim 11, further comprising:

the first control unit, the second control unit, and the pulse wave detection unit according to claim 1.

21. An article manufacture comprising:

a computer readable medium readable by a computer; and

program instructions carried by the computer readable medium for causing the computer to serve as the first control unit, the second control unit, and the pulse wave detection unit according to claim 1.

11. An optical pulse wave detection apparatus comprising:

a light emitting element that emits light to a living organism;

a light receiving element that receives a reflected light of the light that is reflected by the living organism;

a signal control unit for causing the light emitting element to emit the light to the living organism, the signal control unit obtaining a plurality of signals from the light receiving element that receives the reflected light of the light emitted by light emitting element, each of the plurality of signals being obtained at a timing different from each other; and

a pulse wave detection unit for detecting single sampling data based on the plurality of signals, the single sampling data being used for detecting a pulse wave.

12. The pulse wave detection apparatus according to claim 11, wherein an interval between the timing for obtaining each of the plurality of signals is equal to or less than 1 msec.

13. The pulse wave detection apparatus according to claim 11, wherein:

the signal control unit causes the light emitting element to emit the light of a certain light quantity for a plurality of times; and

the signal control unit obtains the each of the plurality of signals at each of the plurality of times for causing the light emitting element to emit the light.

14. The pulse wave detection apparatus according to claim 11, wherein a next one of the plurality of signals is adjusted based on a preceding one of the plurality of signals, the preceding one preceding the next one.

15. The pulse wave detection apparatus according to claim 11, wherein a number of the plurality of signals obtained by the signal control unit is changeable in accordance with a condition for detecting the single sampling data.

16. The pulse wave detection apparatus according to claim 11, wherein a number of the plurality of signals is determined such that at least one of the plurality of signals has a magnitude that stays within an obtainable range of the signal control unit.

17. The pulse wave detection apparatus according to claim 11, wherein a certain one of the plurality of signals is set as the single sampling data, the certain one being obtained at a certain order among the plurality of signals.

18. The pulse wave detection apparatus according to claim 11, wherein:

each of the plurality of signals has a magnitude that stays within an obtainable range of the signal control unit; and

a first one or a last one of the plurality of signals is set as the single sampling data, the first one of the plurality of signals being obtained firstly, the last one of the plurality of signals being obtained lastly.

19. The pulse wave detection apparatus according to claim 11, wherein a calculation result using two or more of the plurality of signals is set as the single sampling data, each of the two or more of the plurality of signals having a magnitude that stays within an obtainable range of the signal control unit.

22. An article manufacture comprising:

a computer readable medium readable by a computer; and

program instructions carried by the computer readable medium for causing the computer to serve as the signal control unit and the pulse wave detection unit according to claim 11.