U.S. patents available from 1976 to present.
U.S. patent applications available from 2005 to present.

Information signal record medium of the capacitance type

Patent 4351747 Issued on September 28, 1982. Estimated Expiration Date: Icon_subject October 28, 2000. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Patent References

3833541

Disc record and method of compounding disc record composition
Patent #: 3960790
Issued on: 06/01/1976
Inventor: Khanna

Sound reproduction compositions
Patent #: 3975321
Issued on: 08/17/1976
Inventor: Heiberger

Molding composition Patent #: 4151132
Issued on: 04/24/1979
Inventor: Khanna

Inventors

Assignee

Application

No. 06/201592 filed on 10/28/1980

US Classes:

252/511, Resin, rubber, or derivative thereof containing252/500, ELECTRICALLY CONDUCTIVE OR EMISSIVE COMPOSITIONS252/572Metal- or insoluble component-containing; e.g., slurry, grease, etc.

Examiners

Primary: Padgett, Benjamin R.
Assistant: Barr, J. L.

Attorney, Agent or Firm

International Classes

C08K 3/08 (20060101)
C08K 3/00 (20060101)
C08K 3/04 (20060101)
G11B 9/00 (20060101)
G11B 9/06 (20060101)

Foreign Application Priority Data

1979-10-29 JP

Abstract

An improvement is provided in and relating to a capacitance-type record medium wherein an information signal is recorded as a variation in the geometrical shape of its surface area, and is played back by the variation of the capacitance between its surface and an electrode of a reproducing stylus scanning the surface of the record medium relatively which occurs according to a variation in the geometrical shape of its surface area. The improvement consists in the fact that at least the surface area of the record medium is formed of (1) a material composed of an electrically conductive substance and a copolymer consisting of 98 to 65% by weight of vinyl chloride, 2 to 20% by weight of an alkyl vinyl ether with the alkyl group having 4 to 18 carbon atoms and/or a vinyl ester of a fatty acid in which the fatty acid residue has 4 to 18 carbon atoms and 0 to 15% by weight of another monomer copolymerizable with these compounds, or (2) a material composed of an electrically conductive substance and a polymer mixture consisting of at least two polymers in which the proportions of the constituent monomers are the same as in the aforesaid copolymer.

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