EP0540140A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Backlighting system for electro-optic displays
Assignee: L3 Technologies ESS Inc
•
Filing: 1992-06-15
•
Granted: —
•
Expires: 2012-06-15
Abstract
Abstract There is described a way to provide night vision viewing compatibility of backlit electrooptic modulated light valve or LCD displays designed for daylight viewing. Liquid crystal displays (LCD) having only backlighting systems which provide a high brightness, good contrast, display under daylight conditions are inappropriate for use in dark, night time, conditions where viewing is desired utilizing electronic night vision equipment. There are described improvements to standard backlighting displays in which, through the utilization of arrays of low-level intensity light sources (37) such as secondary fluorescent light sources, miniature incandescent lamps or light emitting diodes, the lighting means (18) used in daylight vision can be turned off and the secondary low-level lighting sources (37) achieve a minimum intensity acceptable for night vision electronic viewing.
Inventors
- 👤 James Francis Farrell
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 17:15
CPC Classifications
G; G09; G09G; G09G3/00; G09G3/20; G09G3/34; G09G3/3406; G09G3/342; G01; G01D; G01D11/00; G01D11/28; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/1333; G02F1/1335; G02F1/1336; G02F1/133602; G02F1/133603; G02F1/133604; G02F1/133613; G02F1/133626
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
99 words
A backlit electrooptic modulated light valve display device which comprises an electrooptic light valve panel (12) for controllably modifying light being transmitted therethrough into patterns of information and first means (18) for emitting relatively high intensity light through said electrooptic light valve panel and with sufficient intensity for daylight viewing of the display, characterised in that there are second means (37) for emitting relatively low intensity light through said electrooptic light valve panel (12) for use in viewing the panel in dark conditions with night vision equipment whilst the means (18) for emitting relatively high intensity light is deactivated.
Claim 2
Dependent Claim
29 words
A device according to claim 1 wherein the second means (37) are arranged to direct light through portions of the first means (18) before that light reaches the panel.
Claim 3
Dependent Claim
55 words
A device according to claim 1 or 2 and comprising a reflecting surface (20) positioned on a side of the first light emitting means (18) opposite the placement of the electrooptic modulated light valve panel (12) whereby light from said first light emitting means (18) is reflected through said electrooptic modulated light valve panel (12).
Claim 4
Dependent Claim
15 words
A device according to claim 3, wherein the reflecting surface (20) contains through slots (23).
Claim 5
Dependent Claim
25 words
A device according to claim 4, wherein the second light emitting means are arranged to emit light through said slots (23) to the panel (12).
Claim 6
Dependent Claim
23 words
A device according to claim 5 and comprising filter means (39) placed between the second light emitting means (37) and said slots (23).
Claim 7
Dependent Claim
23 words
A device according to claim 3 wherein the second light emitting means (22) are embedded within the material defining said reflecting surface (20).
Claim 8
Dependent Claim
28 words
A device according to claim 1 or 2 wherein the first means for emitting high intensity light comprises a side illuminated, internally reflecting, light pipe or guide (82).
Claim 9
Independent Claim
29 words
A device according to any one of the preceding claims wherein the first means (18) for emitting relatively high intensity light comprises at least one primary, fluorescent, lighting means.
Claim 10
Dependent Claim
22 words
A device according to claim 9, wherein said first means for emitting relatively high intensity light comprises a flat fluorescent lamp (52).
Claim 11
Independent Claim
29 words
A device according to any one of the preceding claims and comprising a diffusing means (16) placed between the first lighting means (18) and the light valve panel (12).
Claim 12
Independent Claim
29 words
A device according to any one of claims 1 to 10 and comprising a filter means placed between the first lighting means (18) and the light valve panel (12).
Claim 13
Independent Claim
46 words
A device according to any one of the preceding claims comprising at least one secondary, fluorescent, lighting means (37) as the means for emitting relatively low intensity light and which is arranged to transmit light through the deactivated means (18) for emitting relatively high intensity light.
Claim 14
Independent Claim
21 words
A device according to any one of claims 1 to 12, wherein the second means comprises multiple light emitting sources (22).
Claim 15
Dependent Claim
32 words
A device according to claim 14 when appended to claim 2, wherein said sources are associated with optical lenses which aid in focusing the emitted low-level light into the first means (18).
Claim 16
Dependent Claim
45 words
A device according to claim 14 or 15 wherein the sources (38) are associated with filters (36) to controllably further reduce the relatively low intensity light emitted to a preselected level suitable for viewing the panel display (12) in the dark with night vision equipment.
Claim 17
Independent Claim
21 words
A device according to any one of claims 14 to 16, wherein said sources are an array of light emitting diodes.
Claim 18
Independent Claim
21 words
A device according to any one of claims 14 to 16, wherein said sources comprise an array of miniature incandescent lamps.
Claim 19
Independent Claim
19 words
A device according to any one of the preceding claims wherein said panel (12) is a liquid crystal panel.
Claim 20
Independent Claim
27 words
A device according to any one of the preceding claims and arranged so as to be operable to define readable coloured patterns of information at the panel.
Claim 21
Independent Claim
24 words
A device according to any one of the preceding claims, wherein the second means are arranged to emit light substantially excluding the infrared region.
References Cited (Backward Citations)
US3950078A
Cited
US4573766A
Cited
US4799771A
Cited
US5046826A
Cited
US4934793A
Cited
EP0364346A1
Cited
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.