Electric lamp and discharge devices: systems – Plural power supplies – Plural cathode and/or anode load device
Reexamination Certificate
1999-11-09
2001-07-24
Wong, Don (Department: 2821)
Electric lamp and discharge devices: systems
Plural power supplies
Plural cathode and/or anode load device
C315S149000, C315S291000, C315S307000
Reexamination Certificate
active
06265833
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a self-emitting display device, and more particularly, to an apparatus and method for driving a self-emitting display device.
2. Background of the Related Art
Generally, a self-emitting display device spontaneously emits a light when electric power or other energy is applied thereto. There are an organic electroluminescence (EL) display, an inorganic light emitting diode, an inorganic EL display, a field effect display, a plasma display panel, and the like in the self-emitting display device.
The self-emitting display device has good visibility outer illumination is low. On the contrary, the self-emitting display device has poor visibility as outer illumination is high. For example, visibility becomes poor in the outside environment where the intensity of light is high.
Most of the self-emitting display devices have a number of control switches which intermittently vary their emitting luminance or control knobs which gradually vary their emitting luminance, so that a user can control emitting luminance using the control switch or the control knob if the intensity of light in the outside environment is high. However, in this case, since the user should directly control emitting luminance of the display device in accordance with the use environment, there brings the user inconvenience and also there are no benefits in time and effects.
To solve such problems, there has been proposed a method for automatically controlling emitting luminance of a display device in which an optical sensor is used to senses the brightness of the outside environment. This method is adapted to control the brightness of a back light of a liquid crystal display (LCD) not a self-emitting display device. The method for automatically controlling emitting luminance of a display device includes the steps of sensing brightness of the outside environment by the optical sensor, and controlling the electric power applied to the back light in accordance with the brightness to automatically control the emitting luminance of the display device. In this method, in the case that the outside environment is dark, it is determined whether the intensity of light in the outside environment sensed by the optical sensor is less than a reference value. If so, the emitting luminance of the display device increases by increasing the electric power applied to the back light more than the reference value. In the case that the outside environment is bright, the emitting luminance of the display device decreases by decreasing the electric power applied to the back light less than the reference value. As a result, the emitting luminance of the display device can be controlled automatically.
Since this method automatically controls the emitting luminance of the display device, power consumption can be reduced and inconvenience of the user can be removed. However, since the electric power of the back light increases or decreases in accordance with the intensity of light of the outside environment, it makes the sight of the user unstable, thereby causing fatigue to the user. In other words, it is difficult to distinguish images or information characters when the emitting luminance of the display device is too low, while glaring occurs when the emitting luminance of the display device is too high, thereby reducing efficiency of work and causing eyestrain.
SUMMARY OF THE INVENTION
Accordingly, the present invention is directed to an apparatus and method for driving a self-emitting display device, that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
An object of the present invention is to provide an apparatus and method for driving a self-emitting display device, in which a driving voltage and a driving current are controlled in accordance with variation of the outside environment to automatically control emitting luminance of the display device.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, an apparatus for driving a self-emitting display device provided with an optical signal converter for converting external light and a display device, according to the present invention includes: a controller for a control signal for converting a predetermined driving current and driving voltage in accordance with a signal converted by the optical signal converter and a signal indicating whether or not the display device is in use; and a driver for simultaneously converting the driving current and driving voltage in accordance with the control signal output from the controller, and automatically controlling emitting luminance of the display device and at the same time optimally setting power consumption.
In another aspect, an apparatus for driving a self-emitting display device provided with an optical signal converter for converting external light and a display device includes: a controller for selecting driving modes corresponding to a predetermined driving current and driving voltage in accordance with a signal converted by the optical signal converter and a signal indicating whether or not the display device is in use, and outputting a corresponding driving mode control signal; and a driver for simultaneously converting the driving current and driving voltage applied to the display device in accordance with the driving mode control signal output from the controller, and automatically controlling emitting luminance of the display device and at the same time optimally setting power consumption.
It is characterized in that the controller includes a driving mode selector for selecting a driving mode corresponding to a predetermined driving current and driving voltage in accordance with the signal converted by the optical signal converter and the signal indicating whether or not the display device is in use.
It is characterized in that the driver includes a driving current controller for controlling the driving current in accordance with the driving mode control signal of the controller, a driving voltage controller for controlling an actual driving voltage of the driving voltage in accordance with the driving mode control signal of the controller, a driving voltage generator for generating an actual driving voltage corresponding to the control signal output from the driving voltage controller, and a driving driver for driving the display device in accordance with the driving current output from the driving current controller and the actual driving voltage generated by the driving voltage generator, and controlling the emitting luminance.
In other aspect, a method for driving a self-emitting display device in which the intensity of light of the outside environment is sensed to convert the sensed intensity of light to an electrical signal, includes the steps of: detecting whether or not a display device is in use; outputting a control signal for converting a predetermined driving current and driving voltage in accordance with the converted electrical signal; controlling levels of the predetermined driving current and driving voltage in accordance with the control signal to set levels of an actual driving current and an actual driving voltage; and automatically controlling emitting luminance of the display device in accordance with the level of the predetermined driving current and the level of the actual driving voltage.
It is characterized in that the detecting step includes steps of outputting a control signal for converting the predetermined driving current and driving voltage at a minimum value if the display device i
Kim Hak Su
Kim Moo Seop
Kim Sung Tae
Lee Eun Young
Fleshner & Kim LLP
LG Electronics Inc.
Vo Tuyet T.
Wong Don
LandOfFree
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