Projection screen with retro-reflective calibration points, placement tool and method

• US 5,638,208 A
• Filed: 07/23/1996
• Issued: 06/10/1997
• Est. Priority Date: 07/23/1996
• Status: Expired due to Term

• Current Assignee: Evans & Sutherland Computer Corp. (Elevate Entertainment, Inc.)
• Original Assignee: Evans & Sutherland Computer Corp. (Elevate Entertainment, Inc.)
• Inventors: Walker, Joe L.
• Primary Examiner(s): MALLEY, DANIEL PATRICK
• Application Number:
  US08/685,154
• Time in Patent Office: 322 Days
• Field of Search: 359/443, 359/451, 359/459
• US Class Current: 359/443
• CPC Class Codes: G03B 21/56 Projection screens

Abstract

In a multiple-projector concave-screen display system, spacial alignment of images on the screen, is enabled by designating calibration points with retro-reflective dots and illumination markers. The manufacture of the screen involves locating calibration points and depositing the dots with a tool utilizing a rotary mechanism for loading and applying the dots from solenoid actuated pod units. Areas for retro-reflective dots, versus illumination markers, are defined on the basis of reflectance angles between vectors to the screen from a projector and from the screen to a viewer.

Claims

1. A projection display screen structure for use with light image projection apparatus to display images to a viewer whereby calibration points are specified to facilitate spacial alignment, said projection display screen structure comprising:

a display screen defining a display surface for receiving light images from said projection apparatus; and

a plurality of retroreflective markers affixed to said display surface at said calibration points whereby to reflect light directionally back to a source for locating said calibration points as during alignment operations.

2. A projection display screen structure in accordance with claim 1 further including a plurality of illumination devices affixed to said display screen providing illumination at select calibration points.

3. A projection display screen structure in accordance with claim 2 wherein said plurality of retro-reflective markers are located at calibration points having a less than critical angular position with respect to said projection apparatus and said viewer.

4. A projection display screen structure in accordance with claim 3 wherein said plurality of retro-reflective reference markers comprise dots of retro-reflective material adhesively affixed to said display surface.

5. A process for producing a projection display screen structure for use with light image projection apparatus to display images to a viewer and whereby calibration points are specified for facilitating spacial alignment, said process including the steps of:

providing a display screen for displaying images with identified calibration points on said screen;

specifying a critical size reflectance angle defined by vectors from said projection apparatus and said viewer to individual of said calibration points;

fixing a retro-reflective reference marker at calibration points on said screen having a reflective angle above said critical size reflectance angle; and

mounting an illumination device at calibration points on said screen having a reflectance angle below said critical size reflectance angle.

6. A process according to claim 5 where in said critical size reflectance angle is determined based on the gain of said display screen.

7. A process according to claim 5 wherein said step of fixing a retro-reflective reference marker to said screen comprises adhesively affixing a dot of retro-reflective material.

8. A process according to claim 7 wherein said dot of retro-reflective material is of small size to be not visibly annoying.