Patent US4482206A successfully refreshed from Google Patents.
US4482206A
Expired / Lapsed
US
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Rear projection television screen having a multi-surface Fresnel lens
Assignee: RCA Licensing Corp
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Filing: 1983-04-21
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Granted: 1984-11-13
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Expires: 2003-04-21
Abstract
Abstract A rear projection television receiver comprising a rear projection screen that incorporates a compound Fresnel field lens. The field lens comprises two circular Fresnel lenses that together provide the total refraction for the light impinging on the screen. The angle of incidence of the light striking the individual Fresnel elements is reduced, thereby reducing the amount of light reflected from the Fresnel surfaces. The screen efficiency, especially near the edges of the screen, is thereby increased.
Inventors
- 👤 Bertram VanBreemen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 18:50
CPC Classifications
G; G03; G03B; G03B21/00; G03B21/54; G03B21/56; G03B21/60; G03B21/62; G03B21/625
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
106 words
A rear projection television receiver comprising: a video image source; and a rear projection screen comprising: a field lens for substantially collimating light from said mirror and incorporating a first circular Fresnel lens for receiving light from said mirror for refracting said light through a first angle and a second circular Fresnel lens for receiving said light from said first Fresnel lens for refracting said light through a second angle, the region between said first and second Fresnel lenses being substantially devoid of any light reflecting surfaces; and a focusing lens incorporating an image surface for focusing light from said field lens onto said image surface.
Claim 2
Dependent Claim
106 words
A rear projection television receiver comprising: a video image source; and a rear projection screen comprising: a field lens for substantially collimating light from said mirror and incorporating a first circular Fresnel lens for receiving light from said mirror for refracting said light through a first angle and a second circular Fresnel lens for receiving said light from said first Fresnel lens for refracting said light through a second angle, the region between said first and second Fresnel lenses being substantially devoid of any light reflecting surfaces; and a focusing lens incorporating an image surface for focusing light from said field lens onto said image surface.
Claim 3
Dependent Claim
40 words
The arrangement defined in claim 1, wherein each of said first and second Fresnel lenses comprises a plurality of concentric circular Fresnel elements, said elements of said first Fresnel lens concentrically aligned with said elements of said second Fresnel lens.
Claim 4
Dependent Claim
21 words
The arrangement defined in claim 2, wherein the width of said circular Fresnel elements is of the order of 0.015 inches.
Claim 5
Dependent Claim
43 words
The arrangement defined in claim 1, wherein said light impinges on said first and second Fresnel lenses at an angle less than 40° with respect to the surface normal to said first and second Fresnel lenses at all points on said field lens.
Claim 6
Dependent Claim
39 words
The arrangement defined in claim 1, wherein each of said first and second Fresnel lenses comprises a front and rear surface with said rear surface of said first Fresnel lens facing said rear surface of said second Fresnel lens.
Claim 7
Dependent Claim
14 words
The arrangement defined in claim 1, wherein said field lens is made of plastic.
Claim 8
Dependent Claim
19 words
The arrangement defined in claim 1, wherein said focusing lens comprises a plurality of vertically disposed lenticular lens elements.
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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) | 1987-11-13 | 1988-05-14 | 1988-11-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-11-13 | 1992-05-14 | 1992-11-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-11-13 | 1996-05-14 | 1996-11-13 | $7700.00 | Window Closed / Lapsed |