Compound anamorphic mirror and frame for off-axis reflected image modification

• US 4,299,446 A
• Filed: 11/05/1979
• Issued: 11/10/1981
• Est. Priority Date: 11/05/1979
• Status: Expired due to Term

• Current Assignee: Atari Incorporated (Infogrames Entertainment SA)
• Original Assignee: Atari Incorporated (Infogrames Entertainment SA)
• Inventors: Jenkins, Harry H. Jr.
• Primary Examiner(s): Evans, F. L.
• Application Number:
  US06/091,629
• Time in Patent Office: 736 Days
• Field of Search: 273/DIG. 28, 358/185, 358/242, 358/250, 358/254, 358/231, 353/98, 350/181, 350/293, 350/296, 350/320, 350/174
• US Class Current: 359/846
• CPC Class Codes: G02B 5/10 with curved faces

Abstract

A system for constructing an anamorphic mirror which reflects an image from an off-axis source such as a CRT display is disclosed. A rectangular frame is provided which has rectilinear top, bottom and side portions defining an inwardly directed continuous groove. The groove is linear along the side portions of the frame, and curved concavely along the top and bottom portions of the frame. A flexible reflective element is provided which is flat and has a trapezoidal shape widest at the top in its unflexed configuration. The element is flexed into a curved shape and inserted into the groove in the frame so that it retains its flexed configuration. The reflective element thus provides a mirror in which the reflected image is expanded towards the sides and presents a one-dimensional infinity effect to simulate a wide field having a variable depth, while maintaining the borders of the field linear to provide the illusion of a rectangle laid back at the top.

Claims

1. Apparatus for providing an anamorphic mirror which reflects an image from an off-axis curved source such as a CRT display so that the reflected image is expanded toward the sides to simulate a wide field and presents a one dimensional infinity effect, said apparatus comprising:

a frame having top and bottom portions defining first and second inwardly directed continuous grooves curved concavely along the top and bottom portions of the frame, respectively, said first and second grooves defining first and second conic sections with foci of different magnitudes; and

a flexible reflective element which is flat and has a trapezoidal shape widest at the top in its unflexed configuration, said element being flexed into a curved shape and inserted into the grooves in the frame to provide a reflector having the desired reflection characteristics.

2. Apparatus as recited in claim 1 wherein said first and second conic sections are substantially parabolic and the flexed reflective element defines a substantially parabolic surface of variable focus between said first and second grooves.

3. Apparatus as recited in claim 2 wherein the magnitude of the focus of the parabolic surface of the reflective element decreases toward the top of the element.

4. The apparatus of claim 1 wherein said frame further includes flanking side portions defining linear grooves in registration with said first and second grooves.

6. Apparatus as recited in claim 1 or 5 wherein the reflective element comprises an acrylic material.

7. Apparatus as recited in claim 4 or 5 wherein one side portion of the frame is removably attachable to the top and bottom portions thereof to facilitate insertion and removal of the reflective element within the frame.

5. Apparatus for providing an anamorphic mirror which reflects an image from an off-axis curved source such as a CRT display so that the reflected image is expanded toward the sides to simulate a wide field and has a one-dimensional infinity effect, said apparatus comprising:

a rectangular frame having rectilinear top, bottom and side portions defining an inwardly directed continuous groove which is linear along the side portions of the frame and has a concave shape along the top and bottom portions of the frame defining first and second parabolic curves, the first parabolic curve defined by the groove in the top portion of the frame having a shorter focus than that of the second parabolic curve defined by the groove in the bottom portion; and

a flexible reflective element which is flat and has a trapezoidal shape widest at the top in its unflexed configuration, said element being flexed into a curved shape having substantially parabolic plan sections which decrease in focal length toward the top of the element, said element being inserted into the groove in the frame to provide a reflector having the desired reflection characteristics.

8. A method for constructing an anamorphic mirror which reflects an image from an off-axis curved source such as a CRT display so that the reflected image is expanded toward the sides to simulate a wide field and has a one-dimensional infinity effect, said method comprising the steps of:

shaping a flexible reflective element so that said element has a trapezoidal shape in its flat configuration having side edges of equal length and a top edge wider than the bottom edge;

concavely flexing the reflective element so that the side edges are parallel and the reflective element has a substantially paraboloidal surface; and

sliding the flexed reflective element into a grooved frame which maintains the flexed configuration of the reflective element to provide a reflector having the desired reflection characteristics.

9. A method as recited in claim 8 wherein said sliding step includes sliding the flexed reflective element into a grooved frame having top and bottom portions and a connecting side portion which in combination define an inwardly directed groove, and additionally comprising the step of retaining the flexed reflective element within the grooved frame by attaching another side frame portion to the distal ends of the top and bottom portions of the frame.

10. A method as recited in claim 8 wherein said flexing step includes the step of bending the reflective element so that it is substantially parabolic in plan section, the focal length of the parabolic section decreasing toward the top of the reflective element.

11. A method as recited in claim 8 wherein the flexing and sliding steps are performed simultaneously.