Capacitive playback stylus

• US 4,439,855 A
• Filed: 08/12/1981
• Issued: 03/27/1984
• Est. Priority Date: 08/12/1981
• Status: Expired due to Fees

• Current Assignee: RCA Corporation
• Original Assignee: RCA Corporation
• Inventors: Dholakia, Anil R.
• Primary Examiner(s): Faber, Alan
• Application Number:
  US06/292,285
• Time in Patent Office: 958 Days
• Field of Search: 369/126, 369/150, 369/151, 369/170, 369/173
• US Class Current: 369/126
• CPC Class Codes: G11B 9/075 using mechanical contact with record carrier, e.g. by stylus

Abstract

A playback stylus for a capacitive information disc comprising a shank, a dielectric material at one end of the shank, a first conical region of a first angle in an end portion of the dielectric material, a second conical region adjacent to the first conical region of a second angle less than the first angle, and an information recovering terminal region in the first conical region for recovering information recorded in an information track of a capacitive information disc.

Claims

1. A capacitive information disc playback stylus comprising:

a shank;

a dielectric support element at one end of the shank;

a first conical region of a first angle within the range of 40 to 60 degrees in a portion of the dielectric support element, said first conical region terminating at a constricted tip;

a second conical region adjacent to the first conical region and to the shank of a second angle less than the first angle, said second angle being about 30 degrees; and

an information recovery terminal region in the first conical region for recovering information recorded in an information track of a capacitive information disc wherein said region is a keel tip.

2. A stylus in accordance with claim 1 wherein the dielectric support element is bonded to the shank.

3. A stylus in accordance with claim 1 wherein the dielectric support element is made of diamond.

4. A stylus in accordance with claim 1 where the shank comprises titanium.

5. A stylus in accordance with claim 1 wherein the first conical region and the second conical region have a common major axis.

6. A stylus in accordance with claim 5 wherein the major axis of the first conical region and the second conical region is substantially the same as the major axis of the shank.

7. A stylus in accordance with claim 1 wherein said first conial region is about 25 micrometers in height from said tip to said second conical region, and said second region is about 225 micrometers in height from said first conical region to said shank.