US4051535A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnification of television images
Assignee: Individual
•
Filing: 1976-04-09
•
Granted: 1977-09-27
•
Expires: 1996-04-09
Abstract
Abstract A compact, economical system for magnifying a television image. A fresnel lens of focal length up to 10 inches projects an image from a television image source onto a rear projection screen. Lens aberrations and light quality are controlled by an opaque enclosure which fits around the lens, extends toward the screen, and terminates at a variable aperture. A means is provided for intercepting nearly all light from the television source that is directed toward the screen but does not pass through the lens. The system may be adjusted to be compatible with any conventional television set.
Inventors
- 👤 James M. Inglis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 10:56
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/12; H04N9/31; H04N9/3141
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
156 words
A system for magnifying a television image comprising: a fresnel lens of focal length up to 10 inches, an enclosure fitting all around the circumference of said lens and extending in a direction parallel to the optical axis of the lens, a means defining an aperture in the end of said enclosure away from said lens, a means for intercepting light arranged in combination with said lens so that if a television image source is placed on the side of the lens opposite to the direction in which said enclosure extends, substantially along the optical axis of the lens and within 18 inches of the lens, substantially all light emitted from said source and not passing through said lens will be intercepted, the distance between said lens and said aperture being between 20% and 50% of said focal length, and the area of said aperture being between 25% and 50% of the area of said lens.
Claim 2
Independent Claim
156 words
A system for magnifying a television image comprising: a fresnel lens of focal length up to 10 inches, an enclosure fitting all around the circumference of said lens and extending in a direction parallel to the optical axis of the lens, a means defining an aperture in the end of said enclosure away from said lens, a means for intercepting light arranged in combination with said lens so that if a television image source is placed on the side of the lens opposite to the direction in which said enclosure extends, substantially along the optical axis of the lens and within 18 inches of the lens, substantially all light emitted from said source and not passing through said lens will be intercepted, the distance between said lens and said aperture being between 20% and 50% of said focal length, and the area of said aperture being between 25% and 50% of the area of said lens.
Claim 3
Dependent Claim
24 words
A system for magnifying a television image in accordance with claim 1 and further comprising a means for varying the size of said aperture.
Claim 4
Dependent Claim
31 words
A system for magnifying a television image in accordance with claim 1 and further comprising a means for adjustably suspending said lens, said means for intercepting, said enclosure, and said aperture.
Claim 5
Dependent Claim
111 words
A system for magnifying a television image in accordance with claim 3 wherein: said means for intercepting comprises a plate of opaque material formed with a central opening, said enclosure comprises an open ended box of opaque material secured to said plate so that it circumscribes said central opening, said means defining an aperture comprises a sheet of opaque material formed with a rectangular opening, said sheet fitting over the end of said box away from said lens, and said means for adjustably suspending comprises an adjustable arm one end of which is secured to said plate and the other end of which is adapted to attach to a television set.
Claim 6
Dependent Claim
24 words
A system for magnifying a television image in accordance with claim 4 and further comprising a means for varying the size of said aperture.
Claim 7
Dependent Claim
96 words
A system for magnifying a television image in accordance with claim 5 wherein said means for varying the size of said aperture comprises: a set of opaque cards, each card formed with a central opening of a different size, and a three-sided frame attached to said sheet along a raised rim having a height substantially equal to the thickness of said cards so that when one of said cards is inserted between said frame and said sheet and is seated against said rim, the opening in said card is centered over the opening in said sheet.
Claim 8
Dependent Claim
43 words
A system for magnifying a television image in accordance with claim 1 wherein: said fresnel lens has a focal length of 81/2 inches and an area of 35 square inches, and the distance between said lens and said aperture is substantially 2 inches.
Claim 9
Dependent Claim
92 words
A system for magnifying a television image in accordance with claim 1 wherein: said enclosure comprises an open ended box, said means for intercepting comprises an opaque frustum of a rectangular pyramid the larger end of which is adapted to fit around a television image source and the smaller end of which fits around and supports said lens and said box-like enclosure, and said means defining an aperture comprises a sheet of opaque material formed with a rectangular opening, said sheet fitting over the end of said box away from said lens.
Claim 10
Dependent Claim
43 words
A system for magnifying a television image in accordance with claim 8 wherein: said fresnel lens has a focal length of 81/2 inches and an area of 35 square inches, and the distance between said lens and said aperture is substantially 2 inches.
Claim 11
Dependent Claim
137 words
In a system for magnifying a television image of the type employing a source of an inverted television image and a rear projection screen, the improvement comprising: a fresnel lens of focal length up to 10 inches located between said source and said screen so that it projects said image onto the screen, means for intercepting substantially all the light from said source which is directed toward said screen but does not pass through said lens, an enclosure fitting all around the circumference of said lens and extending forward toward said screen, means defining an aperture in the forward end of said enclosure, the distance between said lens and said aperture being between 20% and 50% of said focal length, and the area of said aperture being between 25% and 50% of the area of said lens.
Claim 12
Dependent Claim
137 words
In a system for magnifying a television image of the type employing a source of an inverted television image and a rear projection screen, the improvement comprising: a fresnel lens of focal length up to 10 inches located between said source and said screen so that it projects said image onto the screen, means for intercepting substantially all the light from said source which is directed toward said screen but does not pass through said lens, an enclosure fitting all around the circumference of said lens and extending forward toward said screen, means defining an aperture in the forward end of said enclosure, the distance between said lens and said aperture being between 20% and 50% of said focal length, and the area of said aperture being between 25% and 50% of the area of said lens.
References Cited (Backward Citations)
US2590130A
Cited
US3560649A
Cited
US3632873A
Cited
US3814509A
Cited
US3800085A
Cited
US3909523A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-09-26 | 1981-03-28 | 1981-09-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-09-26 | 1985-03-28 | 1985-09-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-09-26 | 1989-03-28 | 1989-09-27 | $7700.00 | Window Closed / Lapsed |