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EP0915363A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

A method for adjusting the colour temperature in a back-lit liquid crystal display

Assignee: Nokia Oyj
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Filing: 1998-11-04
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Granted: —
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Expires: 2018-11-04
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Abstract

Abstract The invention relates to a method for adjusting the colour temperature in a liquid crystal display with background lighting. According to the invention, the liquid crystal display is lit by two or more background light lamps with different colour temperatures (LAMP 1, 2, 3, 4, 5), the colour temperature range of the background light is extended and better opportunities for adjusting the colour temperature by changing the pass rate of the light are provided. In a more advanced solution, background light lamps with different colour temperatures (LAMP 1, 2, 3, 4, 5) are switched on (S1) separately for setting the colour temperature of the display, and furthermore, the brightness of the background light lamps (LAMP 1, 2, 3, 4, 5) with different colour temperatures can be adjusted separately for setting the colour temperature.

Inventors

  • 👤 Kimmo Siitari

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-01 22:07
CPC Classifications
G; G09; G09G; G09G3/00; G09G3/20; G09G3/34; G09G3/3406; G09G3/3413; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/1333; G02F1/1335; G02F1/1336; G02F1/133602; G02F1/133609; H; H05; H05B; H05B41/00; H05B41/14; H05B41/36; H05B41/38; H05B41/39; H05B41/392; H05B41/3921; G09G2320/00; G09G2320/06; G09G2320/0606; G09G2320/0626; G09G2320/0633; G09G2320/0666

Claims Analysis

Total Claims: 8
Claim 1
Independent Claim 33 words
A method for adjusting the colour temperature in a back-lit liquid crystal display, characterized in that the liquid crystal display is lit by two or more background light lamps with different colour temperatures.
Claim 2
Dependent Claim 30 words
A method according to Claim 1, characterized in that background light lamps with different colour temperatures are switched (7, 9) separately for setting the colour temperature (8) of the display.
Claim 3
Dependent Claim 28 words
A method according to Claim 1, characterized in that the brightness of background light lamps with different colour temperatures is adjusted separately for setting the colour temperature (8).
Claim 4
Dependent Claim 29 words
A method according to Claim 1, 2 or 3, characterized in that the light of the background light lamps is transferred to the liquid crystal display by a photoconductor.
Claim 5
Dependent Claim 56 words
A back-lit liquid crystal display, characterized in that it comprises two or more background light lamps with different colour temperatures (LAMP 1, 2, 3, 4, 5) for the background lighting of the liquid crystal display (4) and a switch (S1) for lighting the background light lamps with different colour temperatures (LAMP 1, 2, 3, 4, 5).
Claim 6
Dependent Claim 18 words
A liquid crystal display according to Claim 5, characterized in that the switch is a selection switch (S1).
Claim 7
Dependent Claim 60 words
A liquid crystal display according to Claim 5, characterized in that the switch is a continuous-state controller enabling continuous adjustment from a situation in which the lamp with the lowest colour temperature (LAMP 1) is lit to a situation in which the lamp with the highest colour temperature (LAMP5) is lit so that the total light intensity remains essentially constant.
Claim 8
Dependent Claim 41 words
A liquid crystal display according to Claim 5, 6 or 7, characterized in that it also comprises a light conductor (3) for transferring the light from the background light lamps (LAMP 1, 2, 3, 4, 5) to the liquid crystal display.

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