Local Dimming PWM Control for Display Contrast and Power
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Solution Overview
Problem
Existing local dimming technologies face limitations in achieving high image contrast while maintaining low power consumption, leading to increased costs in hardware and power supply.
Innovation Solution
The method involves calculating PWM duty cycles for each backlight region, adjusting output currents by decreasing the duty cycle in low backlight regions and increasing it in high regions, and optimizing RGB pixel values to enhance contrast and brightness, while ensuring power efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If local dimming technology divides backlight into multiple regions with separate control, then image quality and contrast are improved, but hardware costs and power consumption increase
Solution Approach 1:
The backlight is divided into multiple independently controllable regions (first backlight region and second backlight region), allowing separate control of brightness in different areas. This segmentation enables high contrast by dimming dark regions while maintaining brightness in light regions, directly improving image quality without requiring all regions to operate at high power levels simultaneously.
Solution Approach 2:
Different backlight regions are assigned different brightness characteristics based on local image requirements. The first backlight region operates at a first brightness level while the second backlight region operates at a second brightness level, optimizing power consumption by providing high brightness only where needed rather than uniformly across the entire display.
2Illumination intensity
If PWM duty cycle is increased to enhance brightness in high backlight regions, then image contrast improves, but overall power consumption increases
Solution Approach 1:
Instead of increasing brightness across the entire backlight, the patent applies high brightness (higher PWM duty cycle) only to specific regions where it is needed (first backlight region), while maintaining lower brightness in other regions (second backlight region). This partial action achieves the necessary contrast for image quality while minimizing overall power consumption.
Solution Approach 2:
The patent dynamically adjusts the PWM duty cycle parameter for different backlight regions based on image content analysis. By changing the duty cycle parameter locally rather than globally, the system achieves high contrast where needed while maintaining energy efficiency overall, resolving the contradiction between brightness enhancement and power consumption.
Data Source
AI summary
An image quality optimization method based on local dimming includes: based on an input image signal, calculating a PWM duty cycle of a current image signal corresponding to each of backlight regions; comparing a preset first PWM duty cycle and a preset second PWM duty cycle with each PWM duty cycle of the current image signal corresponding to each of the backlight regions to determine whether there exists a high backlight region and a low backlight region in the backlight regions; in determining that there exists the high backlight region and the low backlight region, decreasing a PWM duty cycle of the low backlight region to decrease an output current, and increasing a PWM duty cycle of the high backlight region to increase an output current, thereby increasing a contrast of the current image signal. The present application also provides related apparatus and computer readable storage medium.