Method and apparatus for controlling the brightness of a display screen
AssigneeCompaq Computer Corporation
InventorTim L. Zhang
Life of this patent
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Abstract
A method and apparatus of controlling the brightness level of an LCD display. The brightness of a display having two light bulbs may be controlled by illuminating only one bulb to provide a relatively low brightness level or by illuminating both bulbs to provide a relatively high brightness level. This method and apparatus may be particularly useful in AC/DC powered devices, as a single bulb may be lit when the device is operating on DC power to conserve battery power, and both bulbs may be lit when the device is operating on AC power to provide enhanced brightness.
Claims32
An apparatus for controlling a display screen's brightness, the apparatus comprising:
- a first light bulb;
- a second light bulb positioned in spaced apart relation to the first light bulb;
- a diffusion screen positioned in operable relation to the first light bulb and the second light bulb, the diffusion screen providing a relatively consistent brightness level over its entire surface during illumination of one of the first light bulb and the second light bulb and during illumination of both the first light bulb and the second light bulb;
- and
- a control circuit coupled to the first light bulb and the second light bulb, the control circuit illuminating one of the first light bulb and the second light bulb in response to a first condition and illuminating both the first light bulb and the second light bulb in response to a second condition.
An apparatus for controlling a display screen's brightness, the apparatus comprising:
- a first light bulb positioned behind the display screen and adjacent a top edge of the display screen;
- a second light bulb positioned behind the display screen and adjacent a bottom edge of the display screen;
- a diffusion screen positioned behind the display screen between the first light bulb and the second light bulb, the diffusion screen providing a relatively consistent brightness level over its entire surface during illumination of one of the first light bulb and the second light bulb and during illumination of both the first light bulb and the second light bulb;
- and
- a control circuit coupled to the first light bulb and the second light bulb, the control circuit illuminating one of the first light bulb and the second light bulb in response to a first condition and illuminating both the first light bulb and the second light bulb in response to a second condition.
An AC/DC powered device comprising:
- a display screen having a top edge and a bottom edge;
- a first light bulb positioned behind the display screen and adjacent the top edge of the display screen;
- a diffusion screen positioned behind the display screen between the first light bulb and the second light bulb, the diffusion screen providing a relatively consistent brightness level over its entire surface during illumination of one of the first light bulb and the second light bulb and during illumination of both the first light bulb and the second light bulb;
- and
- a control circuit coupled to the first light bulb and the second light bulb, the control circuit illuminating only the first light bulb during DC operation of the device and illuminating both the first light bulb and the second light bulb during AC operation of the device.
A method of controlling a display's brightness, the display having a display screen, a diffusion screen positioned behind the display screen, a first light bulb, and a second light bulb, wherein the first and second light bulbs are positioned behind the display screen in operable relation to the diffusion screen, the method comprising the steps of:
- illuminating only the first bulb in response to a first condition;
- illuminating the first light bulb and the second light bulb in response to a second condition;
- and
- providing a relatively consistent brightness level over the entire surface of the diffusion screen during illumination of one of the first light bulb and the second light bulb and during illumination of both the first light bulb and the second light bulb.
A method of controlling a display's brightness, the method comprising the steps of:
- providing a display screen;
- positioning a diffusion screen behind the display screen;
- positioning a first light bulb and a second light bulb behind the display screen in operable relation to the diffusion screen, the diffusion screen providing a relatively consistent brightness level over its entire surface during illumination of one of the first light bulb and the second light bulb and during illumination of both the first light bulb and the second light bulb;
- illuminating the first light bulb in response to a first condition;
- and
- illuminating the first light bulb and the second light bulb in response to a second condition.
An AC/DC powered device comprising:
- a display, the display having a display screen, a diffusion screen positioned behind the display screen, a first light bulb, and a second light bulb, the first and second light bulbs being positioned behind the display screen in operable relation to the diffusion screen;
- means for providing a relatively consistent brightness level over its entire surface during illumination of one of the first light bulb and the second light bulb and during illumination of both the first light bulb and the second light bulb;
- means for illuminating the first light bulb in response to a first condition;
- and
- means for illuminating the first light bulb and the second light bulb in response to a second condition.
A computer system comprising:
- a computer;
- a display screen operably coupled to said computer, said display screen comprising a first light bulb, and a second light bulb positioned in spaced apart relation to the first light bulb, and a diffusion screen positioned in operable relation to the first light bulb and the second light bulb, the diffusion screen providing a relatively consistent brightness level over its entire surface during illumination of one of the first light bulb and the second light bulb and during illumination of both the first light bulb and the second light bulb;
- and
- a control circuit coupled to the computer and coupled to the first light bulb and the second light bulb, the control circuit illuminating one of the first light bulb and the second light bulb in response to a fist condition and illuminating both the first light bulb and the second light bulb in response to a second condition.
Dependencies are inferred from the claim text.