US4796973A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pellicle structure for transmission of mid ultraviolet light
Assignee: DU PONT CHEMICAL AND ENERGY OPERATIONS Inc
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Filing: 1987-09-04
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Granted: 1989-01-10
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Expires: 2007-09-04
Abstract
Abstract A freely standing thin pellicle film of cellulose acetate buterate is formed by spinning on a rotating substrate. After forming, the film is lifted off of the substrate and secured to a metallic frame. The pellicle is for use in the mid ultraviolet range of 280 to 360 nanometers, but can be used also in the deep ultraviolet range, e.g. wavelengths as low as about 240 nanometers. The pellicle prevents dust particles from being focused on a surface which is to be exposed by the ultraviolet radiation.
Inventors
- 👤 Joseph Gordon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 20:15
CPC Classifications
C; C08; C08J; C08J5/00; C08J5/18; B; B29; B29C; B29C41/00; B29C41/02; B29C41/12; G; G03; G03F; G03F1/00; G03F1/62; B29K; B29K2001/00; B29K2001/08; B29K2001/12; B29K2105/00; B29K2105/0058; B29K2105/0073; C08J2301/00; C08J2301/08; C08J2301/14
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
29 words
A pellicle comprising a thin film of substantially uniform thickness which is tautly fixed to one edge of an enclosed frame, said thin film consisting of cellulose acetate butyrate.
Claim 2
Dependent Claim
29 words
A pellicle comprising a thin film of substantially uniform thickness which is tautly fixed to one edge of an enclosed frame, said thin film consisting of cellulose acetate butyrate.
Claim 3
Dependent Claim
21 words
The pellicle of claim 1, wherein said thin film has a thickness of from about 1 micron to about 5 microns.
Claim 4
Dependent Claim
82 words
The pellicle of claim 2 wherein said thin film in the absence of antireflection coatings has a spectral transmission characteristic whereby an average greater than about 90% of incident light in the band of frequencies from 280 nanometers to 360 nanometers is passed by said film, wherein said thin film has an antireflection coating on one of its surfaces and said thin film with coating transmits greater than about 90% of incident light in the band of 240 nanometers to 600 nanometers.
Claim 5
Dependent Claim
21 words
The pellicle of claim 1, wherein the opposite edge of said enclosed frame is adapted for mounting to a silica mask.
Claim 6
Dependent Claim
16 words
The pellicle of claim 4, wherein said thin film has a thickness of about 2.85 microns.
Claim 7
Dependent Claim
46 words
The pellicle of claim 1, wherein said thin film in the absence of antireflection coatings has a spectral transmission characteristic whereby an average greater than about 90% of incident light in the band of frequencies from 280 nanometers to 360 nanometers is passed by said film.
Claim 8
Dependent Claim
16 words
The pellicle of claim 6, wherein said thin film has a thickness of about 2.85 microns.
Claim 9
Dependent Claim
18 words
The pellicle of claim 1, wherein said thin film has an antireflection coating on one of its surfaces.
Claim 10
Dependent Claim
28 words
The pellicle of claim 8, wherein said thin film with coating transmits greater than about 90% of incident light in the band of 240 nanometers to 600 nanometers.
Claim 11
Dependent Claim
16 words
The pellicle of claim 6, wherein said thin film has a thickness of about 2.85 microns.
Claim 12
Dependent Claim
16 words
The pellicle of claim 8, wherein said thin film has a thickness of about 2.85 microns.
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) | 1992-01-10 | 1992-07-11 | 1993-01-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-01-10 | 1996-07-11 | 1997-01-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-01-10 | 2000-07-11 | 2001-01-10 | $7700.00 | Window Closed / Lapsed |