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US 7,067,990 B2Granted
Projection type video display
AssigneeSanyo Electric Co., Ltd.
InventorsHisashi Nagai, Hiroshi Nakamura
Life of this patent
Estimating the term…
Abstract
A projection type video display reduces the flicker in projection images caused by the brightness fluctuation of a light source lamp regardless of the kind of lamp used as a light source lamp. The projection type video display includes a driving control circuit for a light source lamp to control a discharge voltage of the light source lamp to prevent flicker caused by brightness fluctuation.
Claims18
A projection type video display comprising:
- a light source lamp;
- means for providing driving electric power to the light source lamp;
- detecting means for detecting a discharge voltage of the light source lamp;
- monitoring means for monitoring the discharge voltage of the light source lamp;
- determining means for determining whether the discharge voltage of the light source lamp fluctuates based on the output the monitoring means;
- transforming means for transforming an amplitude and/or a frequency of a driving power of the light source lamp in response to the determining means determining that the discharge voltage of the light source lamp is fluctuating;
- and
- means for returning the amplitude and/or the frequency of the driving power of the light source lamp to its initial state when the fluctuation of the discharge voltage of the light source lamp is reduced by transforming the amplitude and/or the frequency of the driving power of the light source lamp.
5 more elements
A projection type video display comprising:
- a detecting circuit to detect a discharge voltage of light source lamp;
- a microcomputer to determine whether or not the discharge voltage of the light source lamp fluctuates by monitoring the discharge voltage of the light source lamp which is detected by the detecting circuit;
- a control circuit to transform the amplitude and/or the frequency of the driving power of the light source lamp when the discharge voltage of the light source lamp fluctuates;
- and to return the amplitude and/or the frequency of the driving power of the light source lamp to its initial state when the discharge voltage of light source lamp does not fluctuate by transforming the amplitude and/or the frequency of the driving power of the light source lamp.
1 more element
An operation method of a projection type video display comprises the step of:
- detecting a discharge voltage of a light source lamp;
- monitoring the discharge voltage of the light source lamp;
- determining whether the discharge voltage of the light source lamp fluctuates based on the monitoring step;
- transforming an amplitude and/or a frequency of a driving power of the light source lamp in response to the determining step determining that the discharge voltage of the light source lamp is fluctuating;
- determining whether the fluctuation of the discharge voltage of the light source lamp is reduced in response to the transforming step;
- returning the amplitude and/or the frequency of the driving power of the light source lamp to its initial state when the fluctuation of the discharge voltage of the light source lamp is reduced by transforming the amplitude and/or the frequency of the driving power of the light source lamp.
3 more elements
Dependencies are inferred from the claim text.