US3720455A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Projection screen
Assignee: Individual
•
Filing: 1971-08-02
•
Granted: 1973-03-13
•
Expires: 1991-08-02
Abstract
Abstract A projection screen comprises a flexible covering forming the picture projecting surface which is stretched to a planar form by an inflatable stiffening structure of flexible material enclosed by the covering.
Inventors
- 👤 J Sahlin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 10:08
CPC Classifications
G; G03; G03B; G03B21/00; G03B21/54; G03B21/56
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
107 words
A projection screen forming a picture projection surface comprising a covering of flexible material for forming a picture projection surface and having a front face and a back face, spaced from each other; an inflatable flexible tube arranged in the space between the front and back faces of the covering to form a frame therein; and an inflatable stiffening member of flexible material arranged in the space between the front and back faces of the covering of flexible material and within the bounds of the frame, the frame and the stiffening member when inflated stretching and rigidifying the covering forming the picture projection surface of the screen.
Claim 2
Dependent Claim
107 words
A projection screen forming a picture projection surface comprising a covering of flexible material for forming a picture projection surface and having a front face and a back face, spaced from each other; an inflatable flexible tube arranged in the space between the front and back faces of the covering to form a frame therein; and an inflatable stiffening member of flexible material arranged in the space between the front and back faces of the covering of flexible material and within the bounds of the frame, the frame and the stiffening member when inflated stretching and rigidifying the covering forming the picture projection surface of the screen.
Claim 3
Dependent Claim
107 words
A projection screen forming a picture projection surface comprising a covering of flexible material for forming a picture projection surface and having a front face and a back face, spaced from each other; an inflatable flexible tube arranged in the space between the front and back faces of the covering to form a frame therein; and an inflatable stiffening member of flexible material arranged in the space between the front and back faces of the covering of flexible material and within the bounds of the frame, the frame and the stiffening member when inflated stretching and rigidifying the covering forming the picture projection surface of the screen.
Claim 4
Dependent Claim
107 words
A projection screen forming a picture projection surface comprising a covering of flexible material for forming a picture projection surface and having a front face and a back face, spaced from each other; an inflatable flexible tube arranged in the space between the front and back faces of the covering to form a frame therein; and an inflatable stiffening member of flexible material arranged in the space between the front and back faces of the covering of flexible material and within the bounds of the frame, the frame and the stiffening member when inflated stretching and rigidifying the covering forming the picture projection surface of the screen.
Claim 5
Dependent Claim
26 words
A projection screen as claimed in claim 1 wherein the stiffening member has a smaller dimension than the frame in the transverse direction of the screen.
Claim 6
Dependent Claim
19 words
A projection screen as claimed in claim 1 wherein the stiffening member forms a ring inscribed in the frame.
Claim 7
Dependent Claim
19 words
A projection screen as claimed in claim 1 wherein the stiffening member forms a grid surrounded by the frame.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-03-12 | 1976-09-11 | 1977-03-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-12 | 1980-09-11 | 1981-03-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-12 | 1984-09-11 | 1985-03-13 | $7700.00 | Window Closed / Lapsed |