US4165155A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Amplitude modulation of light beam
Assignee: International Business Machines Corp
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Filing: 1978-03-27
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Granted: 1979-08-21
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Expires: 1998-03-27
Abstract
Abstract An optical modulator suitable for use with a collimated light beam having a moderate cross section and a fast response time and operational at relatively low voltage includes, for example, a glass prism and a smooth metal surface that are separated by an adjustable gap. The gap is filled with a medium, for example, air, having an index of refraction lower than the prism. A beam of monochromatic light is passed into the prism at a specific angle of incidence to undergo total internal reflection at the glass prism-gap interface. A change of approximately 1 micron in the thickness of the gap is sufficient to change the reflectivity from greater than 95% to essentially zero. The size of the gap is mechanically adjusted and this mechanical device determines the frequency response of the light modulation.
Inventors
- 👤 II Joseph G. Gordon
- 👤 Glenn T. Sincerbox
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 21:38
CPC Classifications
G; G02; G02B; G02B26/00; G02B26/02
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
105 words
An optical device comprising: an optically transparent first material having a first plane surface, a second material having a second plane surface with a negative dielectric constant facing said first surface to form a gap therebetween, a medium filling said gap and having a dielectric constant whose magnitude is less than that of said first material, and means for changing the thickness of said gap wherein the optical thickness of the gap determines the reflectivity of a monochromatic linearly polarized light beam that is passed into said first material and that undergoes total internal reflection at the interface between said first surface and said medium.
Claim 2
Dependent Claim
105 words
An optical device comprising: an optically transparent first material having a first plane surface, a second material having a second plane surface with a negative dielectric constant facing said first surface to form a gap therebetween, a medium filling said gap and having a dielectric constant whose magnitude is less than that of said first material, and means for changing the thickness of said gap wherein the optical thickness of the gap determines the reflectivity of a monochromatic linearly polarized light beam that is passed into said first material and that undergoes total internal reflection at the interface between said first surface and said medium.
Claim 3
Dependent Claim
18 words
A device as described in claim 1 wherein said first material is a prism having a triangular shape.
Claim 4
Dependent Claim
18 words
A device as described in claim 1 wherein said first material is a prism having a hemicylindrical shape.
Claim 5
Dependent Claim
15 words
A device as described in claim 1 wherein said second plane surface is a metal.
Claim 6
Dependent Claim
27 words
A device as described in claim 4 wherein said second plane surface is a metal taken from the group consisting of copper, silver, gold, aluminum and rhodium.
Claim 7
Dependent Claim
13 words
A device as described in claim 1 wherein said medium is a gas.
Claim 8
Dependent Claim
12 words
A device as described in claim 6 wherein said gas is air.
Claim 9
Dependent Claim
14 words
A device as described in claim 1 wherein said means is a mechanical device.
Claim 10
Dependent Claim
14 words
A device as described in claim 4 wherein said means is a piezoelectric transducer.
Claim 11
Independent Claim
84 words
A method of modulating the amplitude of a monochromatic light beam in an apparatus having a smooth metal surface separated from a glass prism by a gap that is filled with a material having an index of refraction that is lower than the glass prism comprising the steps of: passing a monochromatic light beam at an angle of incidence into said glass prism to undergo total internal reflection at the glass prism-gap interface, and changing the thickness of the gap to change the reflectivity.
Claim 12
Independent Claim
84 words
A method of modulating the amplitude of a monochromatic light beam in an apparatus having a smooth metal surface separated from a glass prism by a gap that is filled with a material having an index of refraction that is lower than the glass prism comprising the steps of: passing a monochromatic light beam at an angle of incidence into said glass prism to undergo total internal reflection at the glass prism-gap interface, and changing the thickness of the gap to change the reflectivity.
Claim 13
Dependent Claim
17 words
The method as described in claim 10 including the step of providing a gap filled with air.
References Cited (Backward Citations)
US2565514A
Cited
US3156825A
Cited
US2997922A
Cited
US3559101A
Cited
US3376092A
Cited
US3514183A
Cited
US3556638A
Cited
US3565514A
Cited
US3586872A
Cited
US3832567A
Cited
US3983406A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-08-20 | 1983-02-19 | 1983-08-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-08-20 | 1987-02-19 | 1987-08-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-08-20 | 1991-02-19 | 1991-08-21 | $7700.00 | Window Closed / Lapsed |