LCD White Balance Alignment via Gain Segmentation
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Solution Overview
Problem
Information handling system LCD panels face challenges in achieving optimal brightness uniformity and viewing angles when gain values are set below maximum, leading to luminance variations and suboptimal optical performance.
Innovation Solution
Setting the red, green, and blue gain values to their maximum levels during white balance adjustment and then adjusting the backlight current to achieve a predetermined brightness, such as 200 nits, while storing these settings for future reference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If gain values are reduced to achieve predetermined brightness level (200 nits), then brightness uniformity deteriorates and luminance variation increases, but end user experience improves with comfortable brightness
Solution Approach 1:
The patent segments the brightness control function into two independent parts: (1) gain controls (R, G, B) that affect color temperature and are set to maximum values, and (2) backlight current that controls overall brightness. This segmentation allows each parameter to be optimized independently, preventing the luminance variation that occurs when gain values are reduced for brightness control.
Solution Approach 2:
The patent applies different control strategies to different aspects of display performance: maximum gain values are used to maintain optimal local pixel performance and brightness uniformity, while backlight current is adjusted to achieve the desired overall brightness level. This local quality approach ensures that each parameter is optimized for its specific function.
2Manufacturing precision
If gain values are set to maximum, then LCD panel performance is optimized with better brightness uniformity, but brightness level becomes too high for comfortable viewing
Solution Approach 1:
The patent separates the control of brightness uniformity (achieved through maximum gain values) from the control of overall brightness level (achieved through backlight current adjustment). This allows the display to simultaneously achieve both optimal uniformity and comfortable viewing brightness.
Solution Approach 2:
The patent changes the control parameter for brightness from gain values to backlight current. By using backlight current instead of gain values to control brightness, the system maintains optimal gain settings for uniformity while achieving the desired brightness level through a different parameter that does not affect luminance variation.
3Temperature
If gain values are reduced for white balance adjustment, then color temperature is achieved, but optical performance deteriorates with visible patches and reduced viewing angle quality
Solution Approach 1:
The patent segments color temperature control from brightness control by setting all gain values to maximum and using backlight current for brightness adjustment. This prevents the optical performance degradation that occurs when gain values are reduced for color temperature adjustment.
Solution Approach 2:
The patent changes the approach to color temperature control by using maximum gain values for all color channels and relying on the inherent color characteristics of the LCD panel at full gain, rather than reducing individual gain values to achieve color balance. This maintains optimal optical performance while achieving acceptable color temperature.
Data Source
AI summary
LCD panel white balance adjustment provides a desired brightness with minimal impact on optical performance by maximizing Red, Green and Blue gains of the LCD panel for a predetermined color temperature and then adjusting brightness with backlight current. For example, Red, Green and Blue gain settings are set at substantially their maximum value to achieve a color temperature of 6500 degrees and then brightness for the LCD panel is adjusted to substantially 200 nits with the gains remaining at maximized values.