Patent US4679900A successfully refreshed from Google Patents.
US4679900A
Expired / Lapsed
US
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Bulk diffuser for a projection television screen
Assignee: Philips North America LLC
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Filing: 1986-06-05
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Granted: 1987-07-14
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Expires: 2006-06-05
Abstract
Abstract A bulk diffuser for rear projection television screens which exhibits a Gaussian intensity profile. By appropriately selecting the indices of refraction of the substrate and the spheres therein and the range of diameters of the spheres, the intensity half-angle is made equal to the energy half-angle.
Inventors
- 👤 Thomas S. McKechnie
- 👤 Jill F. Goldenberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 23:12
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
83 words
A bulk diffuser for a rear projection television screen comprising: a substrate having a first index of refraction; and a plurality of spheres dispersed through said substrate, said spheres having a second index of refraction which is different from said first index of refraction, a range of diameters of said spheres and a loading density of said spheres being chosen such that a resulting intensity half-angle and an energy half-angle are substantially equal whereby an intensity profile of said bulk diffuser is Gaussian.
Claim 2
Dependent Claim
83 words
A bulk diffuser for a rear projection television screen comprising: a substrate having a first index of refraction; and a plurality of spheres dispersed through said substrate, said spheres having a second index of refraction which is different from said first index of refraction, a range of diameters of said spheres and a loading density of said spheres being chosen such that a resulting intensity half-angle and an energy half-angle are substantially equal whereby an intensity profile of said bulk diffuser is Gaussian.
Claim 3
Dependent Claim
22 words
A bulk diffuser as claimed in claim 1, wherein said second index of refraction is greater than said first index of refraction.
Claim 4
Dependent Claim
36 words
A bulk diffuser as claimed in claim 1, wherein for a given intensity and energy half-angle, said bulk diffuser has a thickness which is inversely proportional to said loading density of said spheres in said substrate.
Claim 5
Dependent Claim
21 words
A bulk diffuser as claimed in claim 1, wherein said intensity half-angle and said energy half-angle are equal to 8 degrees.
Claim 6
Dependent Claim
28 words
A bulk diffuser as claimed in claim 4, wherein said bulk diffuser has a thickness of 3 mm. and said loading density of said spheres is 2 percent.
Claim 7
Dependent Claim
19 words
A bulk diffuser as claimed in claim 5, wherein said range of diameters of said spheres is 5-25 μm.
Claim 8
Dependent Claim
24 words
A bulk diffuser as claimed in claim 6, wherein said first index of refraction is 1.49 and said second index of refraction is 1.508.
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) | 1990-07-13 | 1991-01-12 | 1991-07-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-07-13 | 1995-01-12 | 1995-07-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-07-13 | 1999-01-12 | 1999-07-14 | $7700.00 | Window Closed / Lapsed |