Auxiliary LED Backlight Compensation for Display Brightness Uniformity
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Solution Overview
Problem
Conventional LCD display devices experience uneven brightness and poor brightness uniformity due to factors like uneven lamp spacing, stray capacitance, and aging of CCFL backlights, leading to deteriorated performance over time.
Innovation Solution
The implementation of auxiliary white or RGB light emitting diode (LED) lights within the light pipe area or strategically placed relative to the main backlights to compensate for brightness, with adjustable color temperature to match existing CCFL panels, and a feedback loop for real-time brightness adjustments using integral or external light metering sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If CCFL backlights are used for lighting the display, then the display can be illuminated, but brightness uniformity deteriorates over time due to aging and physical arrangement issues
Solution Approach 1:
The backlight system is divided into multiple independent LED light sources arranged in a matrix pattern across the display panel. Each LED can be independently controlled to compensate for local brightness variations, transforming a single aging CCFL into multiple stable LED units that maintain uniformity throughout their operational life.
Solution Approach 2:
The patent implements dynamic adjustment of LED brightness parameters through gamma correction and lookup tables (LUTs). By modifying the intensity parameters of individual LEDs based on measured luminance data, the system compensates for aging effects and maintains consistent brightness uniformity over time without physical replacement.
2Illumination intensity
If auxiliary LED lights are added to compensate brightness, then brightness uniformity is enhanced, but device complexity increases
Solution Approach 1:
The patent combines the auxiliary compensation LEDs with the existing backlight structure by integrating them into the same light guide plate and diffuser system. This merging approach allows the compensation function to be added without creating a separate complex subsystem, sharing common structural elements like the light guide plate, diffusers, and reflectors.
Solution Approach 2:
The system incorporates light sensors that automatically detect luminance variations and trigger compensation adjustments without user intervention. The control circuitry self-regulates LED intensities based on real-time feedback, eliminating the need for manual calibration or complex external adjustment mechanisms.
3Reliability
If real-time brightness adjustments are implemented using feedback loop, then optimal display conditions are maintained, but manufacturing precision requirements increase
Solution Approach 1:
The patent implements a multi-zone compensation strategy where the display is divided into multiple measurement and compensation zones. Rather than requiring perfect uniformity across the entire panel, the system applies partial compensation to specific zones with significant deviations, reducing the precision requirements for sensor placement while still achieving acceptable overall uniformity.
Solution Approach 2:
The system performs initial brightness characterization and creates lookup tables (LUTs) during manufacturing or first-use calibration. This preliminary action stores compensation data that can be applied automatically during operation, reducing the need for high-precision real-time adjustments and simplifying both manufacturing and operational 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
This solution significantly enhances brightness uniformity by supplementing light from main backlights, allowing for real-time adjustments to maintain optimal display conditions, addressing the issues of uneven brightness and aging-related degradation.
Implementation Method 1
auxiliary lights (e.g., white light emitting diode and/or 3-color RGB light emitting diode lights) to provide additional light
Implementation Method 2
white or 3-color light emitting diode (LED) lights having an adjustable color temperature
Implementation Method 3
real-time brightness adjustments using integral or external light metering sensors
Data Source
AI summary
Systems and methods for compensating brightness uniformity of transmissive backlit display devices using auxiliary lights to provide additional light to compensate light provided by the main backlights of a backlit image display device. Auxiliary lights may be, for example, embedded into the light pipe area of an image display and/or placed in any other suitable position relative to the main backlights that is suitable for compensating the main backlights. In one example implementation, brightness uniformity of a transmissive image display may be at least partially compensated based at least in part on measured luminance of one or more areas of the display.