US3687530A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for projecting hemispherical motion pictures
Assignee: Midori Kai Co Ltd
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Filing: 1971-03-15
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Granted: 1972-08-29
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Expires: 1991-03-15
Abstract
Abstract An apparatus for projecting hemispherical motion pictures includes a hemispherical screen truncated below its equator and a plurality of equidistantly spaced projectors positioned along the lower periphery of the screen. Each projector is positioned within a projection room having a projection window of generally triangular shape, and a mask is positioned over each window. Each mask has an opening which has substantially the same contour as the contour of the window but which is sized slightly smaller than the window to define a projection ray transmitting portion between the periphery of the projection window and the periphery of the mask opening.
Inventors
- 👤 Toshio Watanuki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 19:42
CPC Classifications
G; G03; G03B; G03B37/00
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
144 words
An apparatus for projecting hemispherical motion pictures comprising a truncated hemispherical screen, a plurality of projectors disposed below the equator of the screen and spaced apart adjacent the periphery of the screen, a projection room for each projector, each projection room having a projection window positioned forwardly of the associated projector, and a mask secured to each projection window, each mask being made of a semitransparent material and having an opening having substantially the same contour as the contour of the projection window and being sized slightly smaller than the window, each mask including a projection ray transmitting portion defined by the periphery of the projection window and the periphery of the opening in the mask and the transparency of the projection ray transmitting portion being greater adjacent the periphery of the projection window than adjacent the periphery of the opening in the mask.
Claim 2
Independent Claim
144 words
An apparatus for projecting hemispherical motion pictures comprising a truncated hemispherical screen, a plurality of projectors disposed below the equator of the screen and spaced apart adjacent the periphery of the screen, a projection room for each projector, each projection room having a projection window positioned forwardly of the associated projector, and a mask secured to each projection window, each mask being made of a semitransparent material and having an opening having substantially the same contour as the contour of the projection window and being sized slightly smaller than the window, each mask including a projection ray transmitting portion defined by the periphery of the projection window and the periphery of the opening in the mask and the transparency of the projection ray transmitting portion being greater adjacent the periphery of the projection window than adjacent the periphery of the opening in the mask.
Claim 3
Dependent Claim
90 words
The apparatus of claim 1 in which each projection window and each mask opening are generally triangular in shape with the apex thereof extending upwardly toward the equator of the screen, each projection window including three convex arcuate sides and each mask opening including three convex arcuate sides spaced inwardly from the sides of the associated window, the transparency of the projection ray transmitting portion of each mask gradually increasing from the periphery of each convex arcuate side of the mask opening toward the convex arcuate side of the window.
Claim 4
Dependent Claim
33 words
The apparatus of claim 1 in which the transparency of the projection ray transmitting portion gradually increases from the periphery of the opening in the mask toward the periphery of the projection window.
Claim 5
Dependent Claim
43 words
The apparatus of claim 1 in which the projection window and the mask opening are generally triangular in shape, the projection window including three convex arcuate sides, the mask opening including three convex arcuate sides spaced inwardly from the sides of the window.
Claim 6
Dependent Claim
23 words
The apparatus of claim 4 in which the apex of the triangularly shaped mask opening extends upwardly toward the equator of the screen.
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) | 1975-08-29 | 1976-02-28 | 1976-08-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-29 | 1980-02-28 | 1980-08-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-29 | 1984-02-28 | 1984-08-29 | $7700.00 | Window Closed / Lapsed |