Compensating Circuit for Display Data Signal Overdriving
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Solution Overview
Problem
Display devices, such as LED and OLED displays, face issues with brightness reaching expected levels due to varying frame periods for different color sub-pixels, leading to blurred images when the image moves, as they require multiple frame periods to achieve the desired brightness, especially with low duty and gray values.
Innovation Solution
A compensating circuit that includes a memory circuit, an offsetting circuit, and an overdriving value generator, which generates offset gray values and overdriving values to progressively compensate the data signal, reducing the number of frame periods needed for a sub-pixel to reach the expected brightness by adjusting the data signal based on emission driving signal duty values and current gray values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a low duty value emission driving signal is used to drive the display device, then power consumption is reduced, but the brightness takes several frame periods to reach the expected brightness level
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing overdriving values in a lookup table before actual display operation. When the emission driving signal has a low duty value, the compensating circuit retrieves pre-computed overdriving values that account for the reduced brightness accumulation, allowing the display to reach expected brightness faster without increasing instantaneous power consumption.
Solution Approach 2:
The patent changes the parameter of the data signal by adding overdriving values to the gray level values based on the duty value of the emission driving signal. This parameter modification compensates for the reduced duty cycle effect, enabling the sub-pixel brightness to reach the expected level in fewer frame periods while maintaining energy efficiency.
2Manufacturing precision
If different color sub-pixels require different numbers of frame periods to reach expected brightness, then color accuracy is maintained, but moving edges become blurred
Solution Approach 1:
The patent applies local quality by providing different overdriving values for different color sub-pixels (red, green, blue) based on their specific characteristics. The lookup table stores color-specific overdriving values that compensate for each sub-pixel's unique response time, allowing each color to reach its expected brightness appropriately while maintaining overall image sharpness for moving edges.
Solution Approach 2:
The patent implements dynamics by making the data signal adaptive and variable based on the duty value of the emission driving signal. The compensating circuit dynamically adjusts the overdriving values according to the current duty value, enabling the display to optimize between color accuracy and motion clarity under different operating conditions.
3Loss of time
If the duty value of the emission driving signal is increased to reduce frame periods, then brightness reaches expected level faster, but power consumption increases
Solution Approach 1:
The patent applies partial or excessive action by adding overdriving values to the data signal that partially compensate for the low duty value effect. Instead of increasing the duty value to its maximum, the patent uses moderate overdriving adjustments that provide sufficient brightness acceleration while consuming minimal additional power, achieving a balanced compromise.
Data Source
AI summary
The disclosure provides a compensating circuit for overdriving a data signal of display device. The compensating circuit includes a memory circuit, an offsetting circuit and an overdriving value generator. The memory circuit stores a first offset gray value of a first frame period. The offsetting circuit receives the first offset gray value, a duty value of an emission driving signal and a current gray value of the data signal. The offsetting circuit generates a second offset gray value of a second frame period according to the duty value, the current gray value and the first offset gray value, and stores the second offset gray value into the memory circuit. The overdriving value generator generates an overdriving value for overdriving the data signal to generate a compensated data signal according to the second offset gray value and the current gray value.