LCD Backlight Driving Method for Light Leakage Reduction
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Solution Overview
Problem
Existing liquid crystal display devices face challenges in eliminating light leakage between adjacent light-emitting regions, leading to reduced contrast and color modulation due to varying LED luminance and temperature-dependent light emission intensity.
Innovation Solution
A backlight driving method that divides the backlight into independent light-emitting blocks, records and corrects light leakage by measuring and calculating the leakage rate, and adjusts light emission based on control signals and measured intensities to minimize influence from adjacent blocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the backlight is divided into multiple light-emitting regions to improve local contrast control, then the contrast ratio is improved, but light leakage from adjacent regions degrades the effectiveness
Solution Approach 1:
The backlight is divided into multiple independent light-emitting regions (first light-emitting region and second light-emitting region) that can be controlled separately. This segmentation allows independent control of each region's luminance, enabling the first region to be dimmed without being affected by light leakage from the second region, thus resolving the contradiction between improving contrast through division and preventing light leakage from adjacent regions.
2Illumination intensity
If LED luminance is increased to improve brightness, then the illumination intensity is improved, but color hue changes due to temperature variations
Solution Approach 1:
The invention employs different types of LEDs (first LED and second LED with different spectral characteristics) in different light-emitting regions. By locally optimizing the LED type selection based on the specific display requirements of each region, the system can maintain stable color hues even when luminance varies, as each region's LED characteristics are suited to its functional requirements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Effectively reduces light leakage, maintaining high contrast and color modulation even with varying LED luminance, and mitigates color hue changes due to temperature variations.
Implementation Method 1
an optical sensor which measures light emission from the backlight
Data Source
AI summary
There is provided a method of driving a backlight of a liquid crystal display device capable of eliminating leakage of light from adjacently-placed light emitting blocks. A gray level and maximum gray level of an input video signal are inputted for every light-emitting block. An output average gray level is calculated and a lighting control signal corresponding to converted luminance is outputted. The drivers responding to the lighting control signal makes LEDs (Light Emitting Diodes) emit light. An average gray level from an output from sensors is calculated. An average gray level, based on an average gray level and a light leakage rate, by taking light leakage into consideration. A gray level correcting signal is outputted in the light-emitting block based on the above output average gray level. An output average gray level is corrected in response to a gray level correcting signal.