OPTICAL DISPLAY APPARATUS

• US 3,840,289 A
• Filed: 12/14/1972
• Issued: 10/08/1974
• Est. Priority Date: 12/14/1971
• Status: Expired due to Term

• Current Assignee: GEC Marconi Limited (Gooding Consumer Electronics Ltd.)
• Original Assignee: David John Day
• Inventors: Day, David John
• Primary Examiner(s): Rubin, David H.
• Application Number:
  US05/314,936
• Time in Patent Office: 663 Days
• Field of Search: 350/173,174,202 356/251,252
• US Class Current: 359/630
• CPC Class Codes: G02B 27/0101 characterised by optical features G02B27/0172 takes precedence

Abstract

A head-up optical display unit comprising a beam-splitting unit having an optical axis along which images of one of two instrumentation displays are transmitted through a beam-splitting layer contained within the unit and along which images of the other instrumentation display are reflected by said beamsplitting layer, said images being respectively produced, on the optical axis and on an axis transverse thereto, by first and second optical systems located respectively in front and to the side of the beam-splitting unit, which comprises a prism unit having at least its front surface on the optical axis formed as a lens surface concave to the front, optical means being provided to receive the images from the beam-splitting unit and to produce a display thereof.

Claims

1. A head-up optical display unit comprising a beam-splitting prism unit, said unit having at least its front surface formed as a lens surface defining a main optical axis, and a beam-splitting layer intersecting said main optical axis within the unit;

a first optical system in front of said prism unit, for producing complete images on the main optical axis of one of two instrumentation displays, which complete images are transmitted by the beam-splitting layer along the main optical axis of the beam-splitting unit;

a second optical system to the side of said prism unit, for producing images on an axis transverse to the main optical axis of the other instrumentation display, which images are reflected by the beam-splitting layer along the main optical axis of the beam-splitting unit; and

optical output means for receiving the images from the beamsplitting unit to produce a display thereof;

wherein the glass path along which the images from said first optical system are transmitted differs in length from the glass path along which images from said second optical system are transmitted, and the front surface of said beam-splitting prism unit is concave to the front, with a curvature such that it minimizes the conflict in spherical aberration between the images transmitted along the two paths.

2. A unit according to claim 1, wherein the beam-splitting unit is a compound component also having its rear surface concave to the front.

3. A unit according to claim 1, for handling images of two instrumentation displays of differing colour, wherein the beam-splitting layer is a dichroic layer.

4. A unit according to claim 1, wherein the surface of the beam-splitting unit receiving light on the transverse axis is a plane surface.

5. A unit according to claim 1, wherein the first optical system comprises at least two lens components, one convergent and one divergent, and the second optical system comprises a divergent component.

6. A unit according to claim 1, wherein the first optical system is located on the main optical axis and the second optical system is located on the transverse axis.

7. A unit according to claim 1, wherein the second optical system is located on an axis parallel to the main optical axis and a reflector is provided for turning the images formed thereby on to the transverse axis.

8. A unit according to claim 1, wherein the optical output means comprises at least one convergent lens component for producing a focussed display on a semireflecting plate.