Pickup device for picking up vibration transmitted through bones

• US 4,596,903 A
• Filed: 04/27/1984
• Issued: 06/24/1986
• Est. Priority Date: 05/04/1983
• Status: Expired due to Term

• Current Assignee: Pilot Man-Nen-Hitsu Kabushiki Kaisha (Berkshire Hathaway Incorporated)
• Original Assignee: Pilot Man-Nen-Hitsu Kabushiki Kaisha (Berkshire Hathaway Incorporated)
• Inventors: Yoshizawa, Naomi
• Primary Examiner(s): Rubinson, Gene Z.
• Assistant Examiner(s): NOT, DEFINED
• Application Number:
  US06/604,493
• Time in Patent Office: 788 Days
• Field of Search: 179/121 C, 179/107 BC, 179/110 A, 367/157, 367/166, 367/171
• US Class Current: 381/151
• CPC Class Codes: G01H 11/08 using piezoelectric devices
• CPC Class Codes: H04R 1/46 Special adaptations for use as contact microphones, e.g. on musical instrument, on stethoscope throat mountings H04R1/14
• CPC Class Codes: H04R 17/02 Microphones

Abstract

A pickup device for picking up vibration transmitted through bones or solid members in human, in which a piezoelectric element is mounted like a cantilever within a substantially rigid liquid-tight case filled with a viscous liquid in such a way that the free end of the piezoelectric element can vibrate with respect to the liquid-tight case. The viscosity of the viscous liquid ranges from 30 to 10,000 cs so that the sharpness of resonance of the piezoelectric element can be suitably suppressed.

Claims

1. A pickup device for detecting auditory vibrations transmitted through bones or other rigid members in a human body, comprising:

a substantially rigid liquid-tight case having a cavity therein, a cantilever-like piezo-electric element having a first end fixed to said case so as to vibrate therewith when said case vibrates in response to auditory vibrations, and a free second end extending into said cavity; and

a viscous liquid having a viscosity in the range 30 cs to 10,000 cs, filling said cavity so as to dampen resonant vibrations of said free end of said piezo-electric element;

said piezo-electric element having a resonant frequency greater than 1.5 KHz and exhibiting a Q in said device less than 3.

2. A pickup device as in claim 1, wherein said viscous liquid is a liquid selected from the group of viscous liquids consisting of paraffin chloride, high-molecular plasticizer, glycol, mineral oil, motor oil, organic solvent, prepolymer and epoxy resin.

3. A pickup device as in claim 1, wherein said case has a small hole for filling said cavity with said viscous liquid and a plug closing said small hole.