US4799786A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of diamond identification
Assignee: BP PLC
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Filing: 1986-06-12
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Granted: 1989-01-24
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Expires: 2006-06-12
Abstract
Abstract A method for the identification of diamonds in which a sample (3) to be identified is placed in a beam of monochromatic laser radiation (2) of pre-determined wavelength. The scattered Raman radiation emitted from the sample (3) is passed through a filter (4) adapted to pass only scattered Raman radiation of frequency characteristic of a diamond. The filtered radiation is then detected by the human eye (5) or a photocell device.
Inventors
- 👤 Donald L. Gerrard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 14:39
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/62; G01N21/63; G01N21/65; G01N21/84; G01N21/87
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
96 words
A method for distinguishing between diamonds comprising the steps of: (a) irradiating a gem to be distinguished with a beam of monochromatic laser radiation, the laser radiation being produced by a low powdered laser and having a wavelength in the range about 450 to 550 nanometers; (b) passing any resultant scattered Raman radiation from said gem through an optical filter adapted to pass only scattered Raman radiation of wavelength characteristic of diamond and, (c) detecting said filtered radiation by the eye of an observer thereby to enable identification of said gem as a diamond or otherwise.
Claim 2
Independent Claim
96 words
A method for distinguishing between diamonds comprising the steps of: (a) irradiating a gem to be distinguished with a beam of monochromatic laser radiation, the laser radiation being produced by a low powdered laser and having a wavelength in the range about 450 to 550 nanometers; (b) passing any resultant scattered Raman radiation from said gem through an optical filter adapted to pass only scattered Raman radiation of wavelength characteristic of diamond and, (c) detecting said filtered radiation by the eye of an observer thereby to enable identification of said gem as a diamond or otherwise.
Claim 3
Dependent Claim
26 words
A method according to claim 1 in which said laser radiation is produced by a helium/neon laser and has a wavelength at or near 543.5 nanometers.
Claim 4
Dependent Claim
22 words
A method according to claim 1 or 2 in which the optical filter comprises a portion of glass having a filtering coating.
Claim 5
Dependent Claim
23 words
A method according to claim 1 or 2 in which the filtering means is at right angles to the scattered beam of radiation.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-01-24 | 1992-07-25 | 1993-01-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-01-24 | 1996-07-25 | 1997-01-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-01-24 | 2000-07-25 | 2001-01-24 | $7700.00 | Window Closed / Lapsed |