GROUND-BASED FLIGHT SIMULATING APPARATUS

• US 3,784,742 A
• Filed: 05/08/1972
• Issued: 01/08/1974
• Est. Priority Date: 05/12/1971
• Status: Expired due to Term

• Current Assignee: Archer Michael Spooner, Daniel Richard Lobb, Donald Burnham, Samuel Walter Honeyball
• Original Assignee: Archer Michael Spooner, Daniel Richard Lobb, Donald Burnham, Samuel Walter Honeyball
• Inventors: Burnham, Donald, Honeyball, Samuel Walter, Spooner, Archer Michael, Lobb, Daniel Richard
• Primary Examiner(s): Britton, Howard W.
• Application Number:
  US05/251,258
• Time in Patent Office: 610 Days
• Field of Search: 178/7.88,DIG.20 350/123,29,170
• US Class Current: 348/123
• CPC Class Codes: G02B 2027/011 comprising device for correcting geometrical aberrations, distortion
• CPC Class Codes: G02B 27/0101 characterised by optical features G02B27/0172 takes precedence
• CPC Class Codes: G02B 5/02 Diffusing elements; Afocal elements
• CPC Class Codes: G09B 9/32 by projected image G09B9/307, G09B9/36 take precedence

Abstract

An infinity visual display for a ground-based vehicle or craft simulator. A view of terrain passed over is obtained by a television camera controlled in simulated motion over a terrain model. The view is projected by a television projector onto a back-projection screen, the front of which screen is viewed by trainee crew by way of a collimating mirror. The television projector and back-projection screen are located overhead of the trainee crew and the collimating mirror in front, facing upwards. To provide for this inclined viewing axis of the screen relative to the projector axis to the screen, the screen must have a diffusing transmission characteristic and preferably a raydeflecting characteristic also.

Claims

1. Visual display apparatus for providing a collimated visual display for viewing by at least one subject, comprising a concave mirror positioned for viewing by the subject, a curved rearprojection screen positioned substantially at the focal surface of the concave mirror and an optical projector positioned to project a visual scene onto the rear-projection screen.

2. Visual display apparatus as claimed in claim 1, in which the said optical projector is positioned with its axis directed towards the concave surface of the rear-projection screen and the said concave mirror, rear-projection screen and optical projector are further-positioned so that a line from the centre of the mirror to the point of intersection of the projector axis with the screen is oblique to the projector axis.

3. Visual display apparatus as claimed in claim 1, in which the axis of the optical projector is redirected by reflection at at least one mirror surface and the said redirected axis passes through the centre of the rear-projection screen and the centre of the concave mirror.

4. Visual display apparatus as claimed in claim 1, for providing a visual display for flight simulation apparatus comprising a dummy flight deck for housing a trainee pilot and co-pilot and for providing a collimated visual display for viewing by at least the trainee pilot, in which the said line from the centre of the mirror to the point of intersection of the projector axis with the screen is oblique to the projector axis in the vertical plane bisecting the said dummy flight deck and the said mirror, screen and projector are further positioned so that the line of view of the mirror by the said trainee pilot is substantially horizontal and the projector axis is positioned above the roof of the flight deck.

5. Visual display apparatus as claimed in claim 4, in which the said concave mirror is substantially spheroidal in shape, the axis of the spheroid of which the mirror forms a part lying substantially in the said vertical plane bisecting the dummy flight deck, the lower focus of the spheroid being substantially at the mid point of the volume of space from which the image is to be viewed, and the upper focus of the spheroid being above the dummy flight deck, whereby the axis of the spheroid is oblique to the vertical.

6. Visual display apparatus as claimed in claim 5 in which the optical projector is a closed-circuit television image projector provided with a television signal from a television camera positioned to view a model, thereby to provide the viewed visual display.

7. Visual display apparatus as claimed in claim 6, in which optical distortion of the television image due to the projector, screen and mirror optical system is compensated by the use of a non-linear scanning raster.

8. Visual display apparatus as claimed in claim 6, in which optical distortion of the television image due to the projector screen and mirror system is compensated by the use of image distorting means, comprising one or more lenses and/or refracting wedges and/or curved mirrors interposed between the optical projector and the back-projection screen.

9. Visual display apparatus as claimed in claim 8, in which the rear-projection screen has both deflecting and diffusing light-transmitting characteristics, whereby an incident light ray from the projector produces an emergent cone of rays, the axial ray of which cone is directed oblIquely towards the said mirror.

10. Visual display apparatus as claimed in claim 9, in which the rear-projection screen has its face directed towards the optical projector made up of prism strips extending across the width of the screen.

11. Visual display apparatus as claimed in claim 9, in which the angle of the prism strips varies progressively from top to bottom of the screen.