US4638470A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus using beam splitter cube with specific characteristics for reading information recorded in a magneto-optic medium
Assignee: Xerox Corp
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Filing: 1984-05-09
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Granted: 1987-01-20
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Expires: 2004-05-09
Abstract
Abstract A system for providing a read signal from a magneto-optic medium wherein a non-rotated leaky beam splitter is utilized to provide both s and p components of the light reflected from the medium to a differential detector arrangement. The beam splitter, which may be of conventional construction and which has the reflected beam striking its medium-facing face at normal incidence, is operated in a leaky mode by utilizing it with a read beam having a wavelength differing from the wavelength for which the beam splitter was designed. One face of the beam splitter can be cut at a small angle off normal to prevent any p-polarized light from entering the differential detector arrangement directly from the light source.
Inventors
- 👤 G. A. Neville Connell
- 👤 Jimmy D. Godwin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:57
CPC Classifications
G; G11; G11B; G11B11/00; G11B11/10; G11B11/105; G11B11/10532
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
252 words
A system for providing a read signal from a magneto-optic storage medium having information encoded as directional magnetized domains, said system including first means for directing a focused, polarized light beam of a given wavelength λ 1 onto regions of the storage medium to provide an information beam having both s and p components due to the polar Kerr effect on the medium, and said system further including second means for measuring the phase direction of said s component of said information beam by referencing it to the phase direction of said p component of said information beam, said second means including a beam splitter cube, said beam splitter cube having the design characteristic of very high transmission of the p component of light of wavelength λ 2 and very high reflectance of the s component of light of wavelength λ 2 , said wavelength λ 2 being different than said wavelength λ 1 , said beam splitter cube being oriented such that said information beam of wavelength λ 1 strikes one of its faces at normal incidence, due to said beam splitter cube being of design wavelength λ 2 said beam splitter cube operates in a leaky mode when the information beam of wavelength λ 1 is incident thereon whereby said beam splitter cube directs a small portion of the p component of the information beam and a large portion of the s component of the information beam along a common path for utilization by other components of said second means.
Claim 2
Independent Claim
252 words
A system for providing a read signal from a magneto-optic storage medium having information encoded as directional magnetized domains, said system including first means for directing a focused, polarized light beam of a given wavelength λ 1 onto regions of the storage medium to provide an information beam having both s and p components due to the polar Kerr effect on the medium, and said system further including second means for measuring the phase direction of said s component of said information beam by referencing it to the phase direction of said p component of said information beam, said second means including a beam splitter cube, said beam splitter cube having the design characteristic of very high transmission of the p component of light of wavelength λ 2 and very high reflectance of the s component of light of wavelength λ 2 , said wavelength λ 2 being different than said wavelength λ 1 , said beam splitter cube being oriented such that said information beam of wavelength λ 1 strikes one of its faces at normal incidence, due to said beam splitter cube being of design wavelength λ 2 said beam splitter cube operates in a leaky mode when the information beam of wavelength λ 1 is incident thereon whereby said beam splitter cube directs a small portion of the p component of the information beam and a large portion of the s component of the information beam along a common path for utilization by other components of said second means.
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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) | 1990-01-19 | 1990-07-21 | 1991-01-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-01-19 | 1994-07-21 | 1995-01-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-01-19 | 1998-07-21 | 1999-01-20 | $7700.00 | Window Closed / Lapsed |