Head up display with a lens decentered to the optical axis of the illumination
US5867287A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 30, 1994 |
| Grant date | Feb 2, 1999 |
| Priority date | — |
| Expiry date | Sep 30, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B2027/0165
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A low cost, compact projection display source that serves as a very bright image source for an automotive head up display. The present invention is comprised of a high intensity halogen light source and a liquid crystal display. The liquid crystal display is controlled by display electronics that write images onto the liquid crystal display that are to be displayed to the driver or passengers of a vehicle. Light output from the high intensity light source is transmitted through a piece of infrared energy absorbing glass, a decentered lens, such as a Fresnel lens, and a diffuser that uniformly backlights the liquid crystal display. Crossed polarizers are used on either side of the liquid crystal display. The high intensity light output transmitted by the liquid crystal display is passed through a yellow-orange output window which is projected onto a toric combiner for display to the driver of the vehicle. A fan provides cooling for the liquid crystal display and display circuitry that interfaces between the display electronics and the liquid crystal display. The projection display source produces a very high contrast (very bright) image source without heat problems. The projection d…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.