US4143544A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fingerprinting crystals
Assignee: General Electric Co
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Filing: 1977-06-22
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Granted: 1979-03-13
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Expires: 1997-06-22
Abstract
Abstract A diamond or cubic boron nitride crystal containing growth discontinuities resulting from changes in the environment of the growing crystal and having at least one smooth outside surface which intersects the growth discontinuities is charged electrostatically, a fine powder is applied to the charged smooth surface and the applied powder produces a pattern on the charged surface which is a delineation of the intersected growth discontinuities.
Inventors
- 👤 Robert C. DeVries
- 👤 Roy E. Tuft
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 23:19
CPC Classifications
G; G01; G01N; G01N33/00; G01N33/389; G01N27/00; G01N27/60
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
140 words
A process for characterizing a crystal selected from the group consisting of natural diamond, synthetic diamond and cubic boron nitride, said crystal containing at least a significant amount of structural growth discontinuities caused by fluctuations in the conditions contacting the growing crystal which comprises providing said crystal with at least one external surface having a surface area of at least 0.1 square millimeter which is at least substantially smooth and without significant elevational differences and which intersects at least a portion of said growth discontinuities, electrostatically charging said crystal so that at least said smooth surface of said crystal is electrostatically charged, applying a powder to said charged surface forming a powder pattern on said charged surface, said powder having a particle size ranging from submicron to about 45 microns, said pattern being a delineation of said intersected growth discontinuities.
Claim 2
Dependent Claim
140 words
A process for characterizing a crystal selected from the group consisting of natural diamond, synthetic diamond and cubic boron nitride, said crystal containing at least a significant amount of structural growth discontinuities caused by fluctuations in the conditions contacting the growing crystal which comprises providing said crystal with at least one external surface having a surface area of at least 0.1 square millimeter which is at least substantially smooth and without significant elevational differences and which intersects at least a portion of said growth discontinuities, electrostatically charging said crystal so that at least said smooth surface of said crystal is electrostatically charged, applying a powder to said charged surface forming a powder pattern on said charged surface, said powder having a particle size ranging from submicron to about 45 microns, said pattern being a delineation of said intersected growth discontinuities.
Claim 3
Dependent Claim
22 words
A process for characterizing a crystal according to claim 1 wherein said crystal is electrostatically charged and said powder is applied simultaneously.
Claim 4
Dependent Claim
23 words
A process for characterizing a crystal according to claim 1 wherein said external surface is mechanically polished before said crystal is electrostatically charged.
Claim 5
Dependent Claim
19 words
A process for characterizing a crystal according to claim 1 wherein said crystal is electrostatically charged by corona discharge.
Claim 6
Dependent Claim
24 words
A process for characterizing a crystal according to claim 1 wherein said powder has a particle size ranging from submicron to about 5 microns.
Claim 7
Dependent Claim
30 words
A process for characterizing a crystal according to claim 1 wherein said powder is selected from the group consisting of an insulating powder, a semiconducting powder and a metallic powder.
Claim 8
Dependent Claim
91 words
A fingerprint of a crystal selected from the group consisting of natural diamond, synthetic diamond and cubic boron nitride, said crystal containing at least a significant amount of growth discontinuities in its structure caused by fluctuations in conditions contacting the growing crystal and having at least one outside surface with a surface area of at least 0.1 square millimeter which is at least substantially smooth and which intersects at least a portion of said growth discontinuities, said fingerprint being composed of a powder pattern produced by the process of claim 1.
Claim 9
Dependent Claim
11 words
A photograph of the fingerprint of said crystal of claim 7.
Claim 10
Dependent Claim
22 words
The fingerprint of said crystal of claim 7 wherein said powder pattern is adhered to the adhesive surface of a transparent tape.
Claim 11
Dependent Claim
20 words
The fingerprint of said crystal of claim 7 wherein said powder ranges in particle size from submicron to 5 microns.
References Cited (Backward Citations)
US2678420A
Cited
US3162040A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-03-12 | 1982-09-11 | 1983-03-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-03-12 | 1986-09-11 | 1987-03-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-03-12 | 1990-09-11 | 1991-03-13 | $7700.00 | Window Closed / Lapsed |