Optical: systems and elements – Holographic system or element – Head up display
Patent
1991-04-26
1992-10-06
Arnold, Bruce Y.
Optical: systems and elements
Holographic system or element
Head up display
359 24, G02B 532, G02B 2710
Patent
active
051537516
ABSTRACT:
The invention relates to a holographic display element which includes a reflection hologram and is attached to, for example, an automobile windshield so as to project light rays carrying images of display information onto the display element from a luminous source in the car. When external light such as sunlight coming is diffracted by the reflection hologram there is a possibility that visible light ranging from 570 nm (greenish yellow) to 780 nm (red) is diffracted into a certain range of angles in a horizontal plane and makes a strange impression on persons viewing the windshield from the outside. According to the invention another reflection hologram having different diffraction characteristics is superposed on the first hologram on the outer side in order that diffraction of visible light into the aforementioned range of angles may become inconspicuous. In one embodiment the second hologram diffracts light of 570-780 nm at angles outside the aforementioned range of angles thereby to prevent undesirable diffraction by the first hologram. In another embodiment the second hologram diffracts different wavelengths into the range of angles so that additive color mixing with visible light diffracted from the first hologram results in whitening of diffracted light or reduction in the excitation purity of diffracted light as viewed outside the vehicle.
REFERENCES:
patent: 5066525 (1991-11-01), Nakamachi et al.
Akamatsu Yoshinori
Ishikawa Tomohisa
Todoriki Tsuyoshi
Arnold Bruce Y.
Central Glass Company Limited
Nissan Motor Co,. Ltd.
Parsons David R.
LandOfFree
Holographic display element does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Holographic display element, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Holographic display element will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1194633