Circular projection and display system using segmented trapezoidal screens

• US 4,991,955 A
• Filed: 04/06/1990
• Issued: 02/12/1991
• Est. Priority Date: 04/06/1990
• Status: Expired due to Fees

• Current Assignee: The Todd-Ao Corporation (Ascent Capital Group, Inc.)
• Original Assignee: The Todd-Ao Corporation (Ascent Capital Group, Inc.)
• Inventors: Vetter, Richard
• Primary Examiner(s): Hayes, Monroe H.
• Application Number:
  US07/506,289
• Time in Patent Office: 312 Days
• Field of Search: 352/69, 352/70, 353/48, 350/125
• US Class Current: 352/69
• CPC Class Codes: G03B 21/56 Projection screens
• CPC Class Codes: G03B 37/04 with cameras or projectors providing touching or overlapping fields of view

Abstract

A circular projection system using segmented trapezoidal screens arranged in a continuous arcuate array about a central vertical axis. The top of each screen is tilted downward. Each screen is illuminated by a projector which is mounted above and behind the screen which opposes it. The image from each projector is also angled downward.

For an eight-screen system, each screen is tilted by approximately 8°. For a nine-screen system, each is tilted by approximately 7°. For maximum linearity, the ratio of the distance between the projector lens and the top of the screen on which it projects to the width of the top of said screen is substantially equal to the ratio of the distance between the projector lens and the bottom of said screen to the width of the bottom of said screen.

Claims

1. A multiple screen picture system comprising:

a plurality of trapezoidal screens, each having a flat reflective surface of trapezoidal shape wherein the screen bottom width is greater than the screen top width;

screen mounting means for mounting said plurality of screens in a continuous arcuate array positioned about a central vertical axis of such array and with each of said screens tilted to face in a downward inclined direction relative to said axis; and

a plurality of motion picture projectors provided to project an image on each of said screens.

2. The multiple screen picture system of claim 1 wherein each of said plurality of motion picture projectors is provided with means for tilting the angle of projection therefor in a downward inclined direction toward an associated one of said screens.

3. The multiple screen picture system of claim 1 wherein:

projector positioning means are provided in association with each of said projectors for positioning the associated projector opposite and vertically above an associated one of said screens upon which it is adapted to project an image; and

means for tilting the angle of projection of each of said projectors in a downward inclined direction toward its associated one of said screens.

4. The multiple screen picture system of claims 1, 2 or 3, wherein the ratio of the distance between the projector lens and the top of the screen to the screen top width is substantially equal to the ratio of the distance between the projector lens and the bottom of the screen to the screen bottom width.

5. The multiple screen picture system of claims 1, 2 or 3, wherein each of said screens is contiguous with an adjacent one of said screens with the reflective surfaces of such adjacent screens being contiguous to one another to provide uninterrupted reflective surfaces about said array.

6. The multiple screen picture system of claims 1, 2 or 3, wherein said plurality of screens comprises eight or nine substantially identical screens arranged in a closed loop circular array to provide a 360°

viewing presentation.

7. The multiple screen picture system of claims 1, 2 or 3, wherein the angle of projection of each of said projectors toward its associated screen and the configuration of the trapezoidal shape of such screen reflective surfaces are provided so that such screen surfaces appear as a rectangle to the projector perspective thereof.

8. The multiple screen system of claim 1 wherein said plurality of screens comprises eight substantially identical screens arrayed in a closed loop circular array to provide a 360°

viewing presentation and wherein each of said plurality of screens is tilted by substantially 7°

from a vertical axis.

9. The multiple screen system of claim 1 wherein said plurality of screens comprises nine substantially identical screens arrayed in a closed loop circular array to provide a 360°

viewing presentation and wherein each of said plurality of screens is tilted by substantially 8°

from a vertical axis.

10. A multiple screen and image projection system comprising:

a plurality of flat trapezoidal image-reflecting screens having wider bottom edges than top edges;

screen mounting means for mounting said screens in an arcuate array, individual ones of said flat screens defining chords of an arc defining an outer extent of said array;

a plurality of projectors, each capable of projecting a rectangular image, and projector mounting means for mounting said projectors at individual locations spaced vertically about said array with individual projectors provided to project downward at an associated one of said screens, whereby said projector rectangular images become trapezoidal reflected images when projected on said screens.

11. A multiple screen and projector system comprising:

a plurality of flat, trapezoidal screens arranged in a generally circular array, individual screens defining adjacent chords lying within a circle encompassing said array;

screen mounting means associated with said screens for mounting each screen with a bottom edge being wider than a top edge of the trapezoidal shape thereof and with each of the screens inclined at a predetermined angle from vertical to face inward and downward relative to the array; and

a plurality of projectors for projecting rectangular images and means for mounting them to project from a location above said array in a downward inclined direction across said array toward a selected one of said screens, the inclined direction of each such projector projecting to its associated screen and the trapezoidal shape of such screen being such that the rectangular image of such projector substantially fits the opposite inclined, flat trapezoidal screen.

12. The multiple screen and image projection system of claim 11 wherein said screen mounting means is provided so as to mount said screen to face in a downward inclined direction for viewing from below said array.

13. The multiple screen and image projection system of claim 11 wherein the ratio of the width of the bottom of each screen to the distance from the projector to such bottom is equal to the ratio of the width of the top of each screen to the distance from the projector to such top.

14. The 360°

picture system of claim 13 wherein the ratio of screen segment top width to top projector throw is equal to the ratio of screen segment bottom width to base projection throw, wherein the screen top and bottom width are the dimensional width of the reflective surface of each of said screen segments at the top and bottom, respectively, and the top and bottom projection throw are the dimensional distances the top and bottom of said segments are from the lens of the associated projector.

15. A 360°

picture system comprising;

a generally circular continuous screen made up of a plurality of flat trapezoidal screen segments, the reflective surfaces of such segments being contiguous to each other to present a substantially continuous, uninterrupted, but segmented reflective surface;

a viewing area below said screen, each of said screen segments being inclined downward to face toward said viewing area; and

a plurality of projector and mounting means for mounting each such projector at a location outside of and above said screen to project downward at a selected one of said screen segments from across the top of said screen.

16. A circular picture system for providing a 360°

picture presentation comprising;

a plurality of flat trapezoidal screens;

screen mounting means for mounting said screens in a circular array about a central vertical axis with each of said screens tilted to face in a downward inclined direction at a predetermined angle relative to said vertical axis; and

a plurality of projectors provided to project a picture image on each of said screens.

17. The circular picture system of claim 16 wherein N is the number of screens, R is the radius of the circular array, each projector is positioned at a height HNY above a lower delimiting plane of the array and at a radial distance HNX outside of the circular array, wherein

HNY=(1+y)*HSC, where y is a predetermined vertical offset factor and HSC is a predetermined screen cylinder height;

HNX=2*x*R, where x is a predetermined radial offset factor; and

wherein the width of the base of each screen is substantially equal to;

space="preserve" listing-type="equation">2*R*sin(180/N).

18. The circular picture system of claim 17 wherein the top screen width TSW of each screen is substantially equal to

19. The circular picture system of claim 18 wherein the height of each screen is substantially equal to HSC/cos(t) where HSC is said screen cylinder height and where t is a predetermined screen tilt angle.

20. The circular picture system of claim 19 wherein

a screen tilt depth STD for each screen is substantially equal to HSC*tan(5);

a base chord depth BCD for each screen is substantially equal to R*(1-cos(180/N));

the top projection throw TPT is substantially equal to SQRT(((1+x)*d-STD-BCD)² +(y*HSC)²); and

wherein the base projection throw BPT is substantially equal to

space="preserve" listing-type="equation">BPT=SQRT((1+x)*d-BCD).sup.2 +(1+y)*HSC).

21. The circular picture system of claim 20 wherein the focal length of the projection lens is substantially equal to:

##EQU3## where FIW is a predetermined film image width and TPT is the top projection throw.

22. A three horizontal level multiple screen picture system for displaying a picture comprising:

a final horizontal level for housing viewers of the picture;

a second horizontal level for containing a plurality of screens, each having a reflective surface, being positioned in a continuous arcuate array about a central vertical axis, and being tilted downward with respect to said axis; and

a third horizontal level containing a plurality of motion picture projectors, each projecting a picture which is directed downward to one of said screens.