Head up display projection system having a double reflecting primary mirror
US5734506A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 19, 1996 |
| Grant date | Mar 31, 1998 |
| Priority date | — |
| Expiry date | Aug 19, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B2027/0169
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Head up display apparatus comprises an image source for projecting an image that is to be displayed, a head up display projection unit, and a combiner for reflecting an image that is viewable. The image source projects an image that is to be displayed. The projection unit comprises a double-reflecting primary mirror that receives the image projected by the image source, and a secondary correcting mirror that receive the image reflected from the primary mirror. The secondary correcting mirror reflects the image back onto the primary mirror, and this image is reflected out of the projection unit to the combiner, which reflects the image that is displayed to a viewer. The dual-mirror, triple-reflection design of the present allows it to be smaller than equivalent designs that do not incorporate a mirror arrangement that provides for double-reflection of the projected image from the primary mirror. The projection unit essentially operates as a three-element design, but contains only two optical elements. The optical performance is better than any equivalent dual-mirror design that does not incorporate a double-reflection light path, and the physical package is more compact.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.