The present invention provides a display which has a modulator, preferably a liquid-crystal cell, adapted to modulate activating UV light (23, 25) input from the rear of the cell on to phosphor-type output elements (7) at the viewer side of the cell, and a pre-collimating device (11) such as a prismatic sheet for partially collimating the input light before it reaches the cell, in order to improve the contrast of the liquid-crystal modulator. In the invention a further collimator is included in the form of a dielectric stack filter (9) between the cell (1) and the output elements (7). This filter is tuned to block the essentially monochromatic input light (25a) emerging from the cell at angles greater than a predetermined angle to the normal to the cell, and also acts to block the passage of light at visible wavelengths. This ensures a good light throughput while eliminating the most harmful (i.e. contrast-degrading) off-axis rays.

Title
Display with dielectric stack filter
Application Number
98810106
Publication Number
1276067
Application Date
August 11, 1998
Publication Date
December 6, 2000
Inventor
W A Crossland
T M Coker
P A Bayley
Agent
liang yong
Assignee
The Secretary Of State For Defence
IPC
G02F 01/1335