Fingertip pulse wave sensor

• US 4,915,116 A
• Filed: 03/28/1989
• Issued: 04/10/1990
• Est. Priority Date: 07/06/1988
• Status: Expired due to Fees

• Current Assignee: Misawa Homes Institute of Research & Development
• Original Assignee: Misawa Homes Institute of Research & Development
• Inventors: Hasebe, Norboru, Ito, Shoji
• Primary Examiner(s): JAWORSKI, FRANCIS J
• Application Number:
  US07/329,535
• Time in Patent Office: 378 Days
• Field of Search: 128/687-689, 128/691, 128/666, 128/633
• US Class Current: 600/479
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence

Abstract

A fingertip pulse wave sensor includes a fingertip supporting base having either a nail supporting surface or a fingertip cushion supporting surface, and a slider having the other of the nail supporting surface and the fingertip cushion supporting surface. The slider is guided on the fingertip supporting base in such a manner as to be slidable in the direction in which it is moved away from or toward the fingertip supporting base. The slider is urged in the direction in which it is moved toward the fingertip supporting base by an elastic body which is capable of applying a substantially fixed amount of pressure with respect to the variations in the slide stroke in the direction in which the slider is moved away from the fingertip supporting base which occur when different fingertips are set. The fingertip pulse wave sensor also includes a light-emitting element disposed in one of the nail supporting surfaces and the fingertip cushion supporting surface, and a light-receiving element disposed on the other of the nail supporting surface and the fingertip cushion supporting surface.

Claims

1. A fingertip pulse wave sensor, comprising:

a fingertip supporting base having a fingertip cushion supporting surface on which a fingertip cushion is set;

a slider having a nail contact surface which is disposed in opposed relationship with said fingertip cushion supporting surface at an interval smaller than the standard thickness of fingertips inserted, said slider being guided on said fingertip supporting base in such a manner as to be slidable in the direction in which said nail contact surface is moved away from or toward said fingertip cushion supporting surface;

an elastic body for urging said slider in the direction in which said nail contact surface is moved toward said fingertip cushion supporting surface, in such a manner that said elastic body applies a substantially fixed amount of pressure to said slider with respect to variations in the slide stroke caused by variations in the position of said nail contact surface where it makes contact with a nail; and

a light-emitting element disposed in either of said fingertip cushion supporting surface and said nail contact surface and a light-receiving element disposed in the other of said fingertip cushion supporting surface and said nail contact surface in opposed relationship with said light-emitting element.

2. A fingertip pulse wave sensor according to claim 1, wherein said fingertip supporting base has a rising surface which includes said fingertip cushion supporting surface and a fingertip guide surface with continues from said fingertip cushion supporting surface, said fingertip cushion supporting surface and said fingertip guide surface being slanted so as to cope with the standard shape of the fingertip cushion of a finger resting in a relaxed state and that of the finger cushion of the finger located between the first and second joints, respectively.

3. A fingertip pulse wave sensor according to claim 1, wherein said fingertip cushion supporting surface has a recess or a hole through which the central portion of the fingertip cushion escapes, a light-emitting element or a light-receiving element being disposed behind said recess or said hole.

4. A fingertip pulse wave sensor according to claim 1, wherein said fingertip supporting base is formed integrally with a body of said sensor.

5. A fingertip pulse wave sensor, comprising:

a fingertip supporting base having a rising surface which includes a fingertip cushion supporting surface and a fingertip guide surface which continues from said fingertip cushion supporting surface, said fingertip cushion supporting surface and said fingertip guide surface being slanted with respect to a bottom surface of said fingertip supporting base so as to cope with the standard shape of a fingertip cushion of a finger resting in a relaxed state and that of the finger cushion of said finger between the first and second joints, respectively;

a slider having a nail contact surface which is disposed in opposed relationship with said fingertip cushion supporting surface at an interval slightly smaller than the standard thickness of a fingertip, said slider being guided on said fingertip supporting base in such a manner as to be slidable slantingly with respect to said bottom surface so that said nail contact surface can be moved away from or toward said fingertip cushion supporting surface;

a constant-load spiral spring accommodated in said fingertip supporting base, an inner end of said constant-load spiral spring being rotatably supported on said slider or said fingertip supporting base and an outer end thereof being connected to said fingertip supporting base or said slider so as to allow said slider to be urged against the separation thereof; and

a light-emitting element disposed in either of said fingertip cushion supporting surface and said nail contact surface and a light-receiving element disposed in the other of said fingertip cushion supporting surface and said nail contact surface.

6. A fingertip pulse wave sensor, comprising:

a fingertip supporting base having a nail supporting surface;

a slider having a fingertip cushion supporting surface which is disposed in opposed relationship with said nail supporting surface at an interval smaller than the standard thickness of fingertips, said slider being guided on said fingertip supporting base in such a manner as to be slidable in the direction in which said slider is moved away from or toward said nail supporting surface;

an elastic body for urging said slider in the direction in which said slider is moved toward said nail supporting surface in such a manner that the pressure applied by said elastic body becomes substantially constant with respect to variatons in the slide stroke of said slider in the direction in which said fingertip cushion supporting surface is moved away from said nail supporting surface when a fingertip is held on said fingertip cushion supporting surface; and

a light-emitting element disposed in either of said fingertip cushion supporting surface and said nail contact surface and a light-receiving element disposed in the other of said fingertip cushion supporting surface and said nail contact surface.

7. A fingertip pulse wave sensor according to claim 6, wherein said nail supporting surface is formed on said fingertip supporting base or a second slider guided on a first slider having said fingertip cushion supporting surface, and said second slider is also urged by an elastic body which is capable of applying a substantially fixed amount of pressure with respect to variations in the slide stroke.