US4701020A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Rear projection screen with improved luminance uniformity
Assignee: NORTH AMERICA PHILIPS CONSUMER ELECTRONICS CORP 100 EAST 42ND STREET NEW YORK NY 10017 A CORP OF DE
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Filing: 1986-09-18
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Granted: 1987-10-20
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Expires: 2006-09-18
Abstract
Abstract Color television rear projection screen having a front vertically oriented lenticular lens array, a circular Fresnel lens component with an infinite second conjugate, and a horizontally oriented linear Fresnel lens component with a finite second conjugate, the screen having improved luminance uniformity.
Inventors
- 👤 Ralph H. Bradley, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 09:56
CPC Classifications
H; H01; H01J; H01J29/00; H01J29/02; H01J29/10; G; G03; G03B; G03B21/00; G03B21/54; G03B21/56; G03B21/60; G03B21/62; G03B21/625; G02; G02B; G02B3/00; G02B3/02; G02B3/08
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
65 words
Color television rear projection screen having a circular Fresnel lens component with an infinite second conjugate, for collimating the light from a projected image, and a front vertically oriented lenticular lens array, for spreading the collimated light horizontally in an audience field; characterized by also having a horizontally oriented linear Fresnel lens component with a finite second conjugate, whereby the screen exhibits improved luminance uniformity.
Claim 2
Dependent Claim
65 words
Color television rear projection screen having a circular Fresnel lens component with an infinite second conjugate, for collimating the light from a projected image, and a front vertically oriented lenticular lens array, for spreading the collimated light horizontally in an audience field; characterized by also having a horizontally oriented linear Fresnel lens component with a finite second conjugate, whereby the screen exhibits improved luminance uniformity.
Claim 3
Dependent Claim
40 words
The screen of claim 1 in which the lenticular lens array comprises mutually parallel sequentially adjacent lenticular lens elements extending the entire vertical length of the screen and separated horizontally from one another by a predetermined distance designated the pitch.
Claim 4
Dependent Claim
47 words
The screen of claim 2 in which each lenticule has a tip surface comprising two side convex cylindrical or flat portions and a central concave cylindrical portion, a height to pitch ratio of at least 1:1 and a pitch to tip width ratio of at least 2:1.
Claim 5
Dependent Claim
70 words
The screen of claim 1 comprising two sections, a front section and a rear section, each section having a front and rear surface: the vertically oriented lenticular lens array located on the front surface of the front section; the circular Fresnel lens located on a surface of the rear section; and the linear Fresnel lens located to the rear of the lenticular lens array on one of the remaining surfaces.
Claim 6
Dependent Claim
23 words
The screen of claim 4 in which the linear Fresnel lens is positioned between the lenticular lens array and the circular Fresnel lens.
Claim 7
Dependent Claim
21 words
The screen of claim 5 in which the linear Fresnel lens is located on the rear surface of the front section.
Claim 8
Dependent Claim
29 words
The screen of claim 5 in which the linear Fresnel lens has an infinite first conjugate and a second conjugate within the range of about 5 to 30 feet.
Claim 9
Dependent Claim
11 words
The screen of claim 1 which additionally comprises optical diffusion means.
Claim 10
Dependent Claim
22 words
The screen of claim 2 in which the lenticular lens array includes light absorbing means in the spaces between adjacent lens elements.
Claim 11
Dependent Claim
20 words
The screen of claim 1 which additionally comprises means for elevating the mean direction of light radiating from the screen.
Claim 12
Dependent Claim
13 words
The screen of claim 10 in which the means comprises a segmented prism.
Claim 13
Dependent Claim
46 words
The screen of claim 1 in which the circular and linear Fresnel lens components are combined into a single Fresnel lens having a compound surface, whereby the second conjugate of the compound lens varies from finite in the vertical direction to infinite in the horizontal direction.
Claim 14
Dependent Claim
25 words
The screen of claim 12 in which the compound Fresnel lens has a minimum second conjugate within the range of about 5 to 30 feet.
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) | 1990-10-19 | 1991-04-20 | 1991-10-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-10-19 | 1995-04-20 | 1995-10-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-10-19 | 1999-04-20 | 1999-10-20 | $7700.00 | Window Closed / Lapsed |