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Mountain, New York USA (Authenticated 2841-0090) Unauthorized use of this<br />
signature is prohibited)<br />
------------------------------------------------------------------------<br />
Date: Sat, 06 Dec 1997 05:38:49 -0800<br />
<strong>From</strong>: Tom Howe<br />
To: ceds@teleport.com<br />
Subject: RE: Stylus Cartridge Manufacture<br />
Mime-Version: 1.0<br />
The diamond tip of the <strong>CED</strong> stylus will probably be the most difficult obstacle<br />
to overcome in re-introducing the production of stylus cartridges. Here's a<br />
summary of the steps involved in its manufacture:<br />
1) <strong>From</strong> natural diamond, prepare .025 x .025 x .2 cm stylus blanks.<br />
2) Polish a flat face on the blank for electrode deposition.<br />
3) Clean the blank in a hot oxidizing acid bath.<br />
4) Rinse in high purity deionized water.<br />
5) Atomically clean by baking in a near vacuum at 1300 deg. C.<br />
6) Sputter titanium on the polished face in pure argon at a power density of<br />
60,000 watts per square meter.<br />
7) Fashion the tip into the proper shape by running it around a keel-lapping<br />
disc.<br />
8) Cut a 140 degree angle into the tip by running it around another lapping<br />
disc.<br />
RCA had to invent the oven in step (5), as no vacuum oven capable of that<br />
temperature had ever before been needed. The lapping discs in the last two steps<br />
were something like a coarse VideoDisc with a uniform groove, and had their own<br />
unique mastering process.<br />
RCA was issued a number of patents regarding stylus design, some of which<br />
weren't filed until 1984. These ones will still be valid until 2004, and would<br />
presently be owned by GE or Thomson. The full patent descriptions are public<br />
documents that will be available at libraries with large government document<br />
sections. Here's a listing by patent number:<br />
4,597,646 Apparatus for positioning a stylus<br />
4,587,570 Stylus kicker having kick energy minimization means<br />
4,574,306 Apparatus and method for automatically measuring the shoe-length<br />
of a video disc stylus<br />
4,561,215 Stylus lapping control<br />
4,560,853 Positioning and bonding a diamond to a stylus shank<br />
4,557,040 Alignment and insertion apparatus for an information-containing<br />
disc stylus<br />
4,536,238 Method and apparatus for aligning a chuck for holding an<br />
information containing disc stylus<br />
4,532,737 Method for lapping diamond<br />
4,516,232 Video disc player with compensation for stylus holder mechanical<br />
resonance
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