RGBW Signal Processing Circuit for LCD Backlight Power Reduction
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Solution Overview
Problem
Liquid crystal display devices face challenges in reducing power consumption while maintaining image resolution and luminosity, as elongating RGBW image signals to reduce backlight power consumption can lead to hue shifts and overflow issues.
Innovation Solution
A signal processing device that calculates an elongation coefficient based on input image signals, converts them into RGBW format, elongates the signals, analyzes them for threshold exceedance, and adjusts pixel values to prevent hue shifts, thereby reducing backlight power consumption without compromising image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the image signal is elongated to reduce backlight power consumption, then power consumption is reduced, but hue shifts and overflow issues occur
Solution Approach 1:
The patent applies preliminary action by performing threshold analysis and adjustment on the RGB pixel values before the elongation process. The adjustment circuit pre-adjusts the RGB pixel values based on threshold comparisons, ensuring that when elongation occurs, the pixel values remain within valid ranges and hue accuracy is maintained. This prevents overflow issues and hue shifts that would otherwise occur during elongation.
2Use of energy by moving object
If the backlight light emission amount is reduced to lower power consumption, then power consumption decreases, but display luminosity deteriorates
Solution Approach 1:
The patent applies local quality by differentiating the treatment of different pixel types within the display. The white subpixel is controlled to emit at full brightness to maintain overall luminosity, while the RGB subpixels have their drive signals adjusted through the elongation and threshold adjustment processes. This allows the backlight to operate at lower power while maintaining perceived brightness through strategic use of the white subpixel.
3Manufacturing precision
If the RGB pixel values are adjusted to prevent overflow, then image resolution is maintained, but color accuracy may be affected
Solution Approach 1:
The patent applies feedback by implementing a threshold analysis circuit that continuously monitors RGB pixel values and provides adjustment signals back to the adjustment circuit. This feedback mechanism ensures that pixel values are adjusted only when necessary to prevent overflow, maintaining color accuracy by making minimal necessary adjustments rather than applying blanket adjustments that would degrade color fidelity.
Data Source
AI summary
A signal processing device includes an elongation coefficient calculation circuit receiving a first image signal including a red pixel value, a green pixel value and a blue pixel value, and determining an elongation coefficient value with respect to one frame based on the first image signal, and an image signal processing circuit receiving the first image signal and the elongation coefficient value. The image signal processing circuit includes an image signal conversion circuit converting the first image signal into a second image signal including a red pixel value, a green pixel value, a blue pixel value and a white pixel value, an elongation processing circuit elongating the second image signal based on the elongation coefficient value, an image signal analysis circuit analyzing the elongated second image signal, and an adjustment circuit adjusting the elongated second image signal.