Display Driver Backlight Control Circuit
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional circuit configurations are unable to combine backlight control methods that reduce power consumption by decompressing display data and adjusting backlight luminance based on external conditions, resulting in either limited power reduction or increased circuit size.
Innovation Solution
A display driver that uses a histogram for only upper pixel values, allowing for combined backlight control with an optical sensor, reducing logic circuit size and achieving high power reduction rates by generating a combined backlight control signal based on luminance rates from both methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a histogram is provided for all pixel values (0 to 255) to achieve high power reduction rate, then power reduction rate increases, but logic circuit size becomes large
Solution Approach 1:
The histogram is segmented to cover only a specific range of pixel values (e.g., 183 to 255) rather than all possible values (0 to 255). This segmentation reduces the number of histogram bins required, thereby decreasing logic circuit size while still capturing the essential luminance distribution for power reduction purposes.
Solution Approach 2:
The patent applies local quality by focusing histogram analysis on the upper portion of pixel values where luminance information is most critical for power reduction. By allocating computational resources only to this specific range, the circuit achieves effective power reduction without the overhead of processing all pixel values uniformly.
2Device complexity
If conventional circuit configuration is used, then circuit size remains small, but combinational use of histogram-based backlight control and optical sensor-based backlight control cannot be realized
Solution Approach 1:
The patent merges histogram-based backlight control and optical sensor-based backlight control into a unified system. The luminance rate from histogram analysis and the luminance rate from optical sensor detection are combined to generate a final backlight control signal, enabling both control methods to work together synergistically without requiring separate independent circuits.
Solution Approach 2:
The circuit is designed with multi-functionality to handle both histogram processing and optical sensor input through a common control pathway. The backlight control signal generation unit can process inputs from either method or both simultaneously, making the circuit adaptable to different operating conditions and content types.
3Device complexity
If method using maximum value is used, then circuit size increase is small, but amount of light emission cannot be reduced significantly
Solution Approach 1:
The patent changes the parameter being analyzed from maximum pixel value to histogram-based luminance distribution. By examining the overall distribution of pixel values rather than relying solely on the maximum value, the system can make more informed decisions about backlight dimming, achieving greater light emission reduction while maintaining acceptable image quality.
Data Source
AI summary
In a display driver, a first backlight control unit using a histogram and a second backlight control unit using an optical sensor can be used in combination. The display driver includes a PWM generating unit setting a control signal value consisting of a product of a luminance rate of X % and a luminance rate of Y % as a luminance rate of a control signal for controlling a backlight with respect to maximum backlight luminance when a luminance rate of a control signal obtained by first backlight control with respect to the maximum backlight luminance is X % and a luminance rate of a control signal obtained by second backlight control with respect to the maximum backlight luminance is Y %.