US3821795A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical low pass filter
Assignee: Minolta Co Ltd
•
Filing: 1972-10-02
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Granted: 1974-06-28
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Expires: 1992-10-02
Abstract
Abstract AN OPTICAL LOW-PASS FILTER UTILIZING A PHASE GRATING IS EMPOLYED IN A COLOR TELEVISION CAMERA SYSTEM. IN ORDER TO ELIMINATE THE HIGHER ORDER SPECTRA WHICH PRODUCE FLARE OR LOW CONTRAST IMAGE, THE STRIPS OF THE PHASE GRATING ARE SO SHAPED THAT THEIR SIDE SURFACES ARE INCLINED TO THE BASE BODY OR SUBSTRATE. SUCH PHASE GRATINGS, FOR EXAMPLE, ARE TRAPEZOIDAL-WAVE, TRIANGULAR-WAVE AND SINUSOIDAL-WAVE PHASE GRATINS. IN THE CASE OF TRAPEZOIDAL SHAPED LAMINAE THE FOLLOWING CONDITIONS APPLY: 1-0.65 D/AE $ COS $ $ 1-0.35 D/AE D/AE $ 2 WHERE AE IS THE EFFECTIVE LAMINA WIDTH, D IS THE SPACING OF THE LAMINA AND $ IS MAXIMUM PHASE RETARDATION INTRODUCED BY THE LAMINAE.
Inventors
- 👤 Y Okano
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 01:51
CPC Classifications
G; G02; G02B; G02B27/00; G02B27/42; G02B27/46; H; H01; H01J; H01J29/00; H01J29/86; H01J29/89; H01J29/898
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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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) | 1977-06-27 | 1977-12-27 | 1978-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-27 | 1981-12-27 | 1982-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-27 | 1985-12-27 | 1986-06-28 | $7700.00 | Window Closed / Lapsed |