US4467172A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for laser engraving diamonds with permanent identification markings
Assignee: Individual
•
Filing: 1983-01-03
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Granted: 1984-08-21
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Expires: 2003-01-03
Abstract
Abstract A laser system for inscribing permanent identification markings on or below the surface of a diamond. A shallow penetration depth and narrow line width is achieved by using a harmonic conversion device to produce an output frequency which is the second harmonic of the fundamental laser frequency in combination with a lens system having a short focal length to provide a high density pinpoint spot of laser energy. The energy intensity can be further regulated by a polarization attenuator. In operation, the diamond is mounted on a movable support structure which insures proper relationship to the laser beam. The process is activated by a computer which supplies positional commands to the movable support and is interfaced with the laser for generating programmed alpha-numeric sequences.
Inventors
- 👤 Jerry Ehrenwald
- 👤 Carl B. Miller, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 16:32
CPC Classifications
B; B44; B44B; B44B7/00; B23; B23K; B23K2101/00; B23K2101/007; B23K2103/00; B23K2103/30; B23K2103/50; B41; B41M; B41M5/00; B41M5/24
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
134 words
A laser apparatus for inscribing permanent markings selectively on or below a target surface comprising a source of coherent electromagnetic radiation in a continuous mode having a fundamental radiation frequency, resonator means including an optical cavity, switch means for transmitting short duration pulses of said radiation from the cavity, fixed focus optical means including short focal length objective lens means for directing the transmitted radiation to a focussed spot at the target surface, conversion means within the optical cavity for modifying the radiation wave length to conform with the focal length of the lens means, said conversion means including a harmonic crystal generator providing a multiple harmonic of the fundamental radiation frequency with the converted wave length being compatibly focusable by the lens means for providing a shallow penetration depth in the target surface.
Claim 2
Dependent Claim
134 words
A laser apparatus for inscribing permanent markings selectively on or below a target surface comprising a source of coherent electromagnetic radiation in a continuous mode having a fundamental radiation frequency, resonator means including an optical cavity, switch means for transmitting short duration pulses of said radiation from the cavity, fixed focus optical means including short focal length objective lens means for directing the transmitted radiation to a focussed spot at the target surface, conversion means within the optical cavity for modifying the radiation wave length to conform with the focal length of the lens means, said conversion means including a harmonic crystal generator providing a multiple harmonic of the fundamental radiation frequency with the converted wave length being compatibly focusable by the lens means for providing a shallow penetration depth in the target surface.
Claim 3
Dependent Claim
31 words
A laser apparatus as claimed in claim 1 wherein the harmonic conversion produces an output frequency which is the second harmonic of the fundamental radiation frequency at one-half the wave length.
Claim 4
Dependent Claim
26 words
A laser apparatus as claimed in claim 2 further including power attenuator means for adjusting the radiation amplitude and corresponding energy density of the focussed spot.
Claim 5
Dependent Claim
27 words
A laser system as claimed in claim 3 further including beam expander means having a lens system for enlarging the radiation beam while simultaneously reducing its divergence.
Claim 6
Dependent Claim
42 words
A laser system as claimed in claim 3 wherein the power attenuator means includes at least one fixed and at least one rotatable polarizer within the path of radiation whereby the transmitted radiation is a vector sum of the relative polarizer positions.
Claim 7
Dependent Claim
34 words
A laser system as claimed in claim 4 further including beam splitter means for directing the radiation to the focussing lens and viewer means for monitoring the target surface through the beam splitter means.
Claim 8
Dependent Claim
34 words
A laser system as claimed in claim 6 further including positioning means for displacing the target surface with respect to the focussed spot, said positioning means including a positioning table controlled by a computer.
Claim 9
Dependent Claim
41 words
A laser system as claimed in claim 7 wherein the computer is interfaced with a shutter for on/off gating of the radiation pulses, whereby the focussed spot on a selected area of the target surface will conform to a programmed code.
Claim 10
Dependent Claim
16 words
A laser system as claimed in claim 8 wherein the switch means includes an acousto-optical Q-switch.
Claim 11
Dependent Claim
21 words
A laser system as claimed in claim 9 wherein the source of electromagnetic energy is solid-state neodymium yttrium aluminum garnet rod.
Claim 12
Dependent Claim
17 words
A laser apparatus as claimed in claim 10 wherein the harmonic generator utilizes a lithium iodate crystal.
Claim 13
Independent Claim
115 words
A method for laser engraving permanent identification markings in the structure of a diamond including the steps of (a) mounting the diamond in a fixture, (b) generating a beam of laser radiation at a constant wave length, (c) modifying the wave length by harmonic conversion for compatibility with a fixed short focal length lens system, (d) selectively focussing the laser beam either on or below a target surface area on the diamond, (e) displacing the fixture with respect to the focussed beam in accordance with a computer program sequence, (f) coordinating on/off laser beam transmission by interfacing the computer with the laser for imprinting a desired format on the target surface area of the diamond.
Claim 14
Independent Claim
115 words
A method for laser engraving permanent identification markings in the structure of a diamond including the steps of (a) mounting the diamond in a fixture, (b) generating a beam of laser radiation at a constant wave length, (c) modifying the wave length by harmonic conversion for compatibility with a fixed short focal length lens system, (d) selectively focussing the laser beam either on or below a target surface area on the diamond, (e) displacing the fixture with respect to the focussed beam in accordance with a computer program sequence, (f) coordinating on/off laser beam transmission by interfacing the computer with the laser for imprinting a desired format on the target surface area of the diamond.
Claim 15
Dependent Claim
52 words
A method for laser inscribing identification markings as claimed in claim 12 wherein the focussed laser beam forms a blackened residue on the target surface when vaporized, and further including the steps of (g) removing the residue and (h) filling the depressions with a selected material for contrasting with the diamond surface.
Claim 16
Dependent Claim
26 words
A method for laser inscribing identification markings as claimed in claim 13 wherein the focussed laser beam has a penetration depth of less than 50 microns.
Claim 17
Dependent Claim
26 words
A method for laser inscribing permanent identification markings as claimed in claim 14 wherein the inscriptions have a character size within the range of 25-125 microns.
Claim 18
Dependent Claim
25 words
A method for laser inscribing identification markings as claimed in claim 15 wherein the target surface area is on a girdle portion of the diamond.
Claim 19
Dependent Claim
22 words
A method for laser inscribing identification markings as claimed in claim 12 wherein the imprinted format is occluded below the target surface.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-08-21 | 1988-02-20 | 1988-08-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-08-21 | 1992-02-20 | 1992-08-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-08-21 | 1996-02-20 | 1996-08-21 | $7700.00 | Window Closed / Lapsed |