US3936147A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Variable characteristic light filter
Assignee: Minolta Co Ltd
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Filing: 1973-10-15
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Granted: 1976-02-03
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Expires: 1993-10-15
Abstract
Abstract A variable color light filter system comprises a variable light filter including a pair of superimposed different color chromatic polarizing components with axes at a right angle to each other and an achromatic polarizing filter component which is rotatable relative to the chromatic polarizing components. A quarter wave length retardation plate is positioned in front of the variable light filter and has its optical axis at 45° to the vertical. In another form the achromatic polarizing filter component is positioned between two pairs of superimposed chromatic polarizing components all of which are of different colors.
Inventors
- 👤 Sanjiro Murakami
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 06:58
CPC Classifications
G; G02; G02B; G02B27/00; G02B27/28; G02B27/288
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
83 words
A variable light filter system comprising a filter having a chromatic polarizing filter section including superimposed first and second chromatic polarizing filter components of different color transmission characteristics and whose polarizing axes are substantially perpendicular to each other and an achromatic polarizing filter section, said chromatic and achromatic polarizing filter sections being rotatable relative to each other, and a quarter wave retardation plate disposed in front of said filter and having its optical axis at an angle of substantially 45° to the vertical.
Claim 2
Dependent Claim
83 words
A variable light filter system comprising a filter having a chromatic polarizing filter section including superimposed first and second chromatic polarizing filter components of different color transmission characteristics and whose polarizing axes are substantially perpendicular to each other and an achromatic polarizing filter section, said chromatic and achromatic polarizing filter sections being rotatable relative to each other, and a quarter wave retardation plate disposed in front of said filter and having its optical axis at an angle of substantially 45° to the vertical.
Claim 3
Dependent Claim
40 words
The variable light filter system of claim 1 including a pair of said chromatic polarizing filter sections, the chromatic polarizing filter sections having different color transmission characteristics, said achromatic polarizing filter section being disposed between said chromatic polarizing filter sections.
Claim 4
Dependent Claim
19 words
The variable light filter system of claim 2 wherein said pair of chromatic polarizing filter sections are relatively rotatable.
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) | 1979-02-02 | 1979-08-04 | 1980-02-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-02-02 | 1983-08-04 | 1984-02-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-02-02 | 1987-08-04 | 1988-02-03 | $7700.00 | Window Closed / Lapsed |