Patent US3856418A successfully refreshed from Google Patents.
US3856418A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Light metering and controlling device
Assignee: Individual
•
Filing: 1973-06-25
•
Granted: 1974-12-24
•
Expires: 1993-06-25
Abstract
Abstract A light metering and controlling device which comprises a support carrying a series of light filters, each varying in the degree of its density or transparency. An aperture is associated with each filter, the aperture being of a calculated area for the passage of a desired amount of light from a light source. The device is particularly useful in determining and controlling the quantity of light issuing from a slide projector in projecting an image on a surface, such as a wall. The area of an aperture is related to the transparency of its associated filter. The projected image is viewed through the filters and the aperture related to the filter through which the projected image is barely visible is the one placed before the projector to thereby control the light therefrom.
Inventors
- 👤 I Levine
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 18:03
CPC Classifications
G; G01; G01J; G01J1/00; G01J1/38; G01J1/40
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
84 words
A light metering and controlling device comprising a support, a series of light filter means mounted in said support, said filter means progressively and decreasingly varying in light transmission therethrough, a series of light apertures in said support, each light aperture being correlated with a respective filter means, the area of each light aperture progressively varying in proportion with the light transmitted through its correlated filter means, the light aperture with the smallest area being correlated with the filter means transmitting the least light.
Claim 2
Dependent Claim
84 words
A light metering and controlling device comprising a support, a series of light filter means mounted in said support, said filter means progressively and decreasingly varying in light transmission therethrough, a series of light apertures in said support, each light aperture being correlated with a respective filter means, the area of each light aperture progressively varying in proportion with the light transmitted through its correlated filter means, the light aperture with the smallest area being correlated with the filter means transmitting the least light.
Claim 3
Dependent Claim
59 words
The device set forth in claim 1 wherein the support is provided with a series of openings and the series of filter means comprise filter elements of progressively varying density, each filter means being aligned with a respective opening, and wherein each of the series of light apertures comprises a hole through the support adjacent its associated filter element.
Claim 4
Dependent Claim
45 words
The device set forth in claim 2 wherein the support comprises two superimposed sheets having aligned openings with each of said filter elements located between the sheets and in alignment with the openings, said superimposed sheets being secured together to thus support the filter elements.
Claim 5
Dependent Claim
24 words
The device set forth in claim 3 wherein the openings in one sheet are deformed to provide pocket formations to house the filter elements.
Claim 6
Dependent Claim
66 words
The device of claim 1 wherein the support is a transparent base and wherein the series of the light filter means comprises a series of areas of the base, each area having a film layer of different light transmitting density thereon, and wherein each light aperture comprises a clear area on the base, the rest of the surface of the base having an opaque layer thereon.
References Cited (Backward Citations)
US1032260A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-12-23 | 1978-06-24 | 1978-12-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-23 | 1982-06-24 | 1982-12-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-23 | 1986-06-24 | 1986-12-24 | $7700.00 | Window Closed / Lapsed |