Display Common Voltage Inclined Waveform Flicker Compensation
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Solution Overview
Problem
Display devices experience significant flickering at low driving frequencies due to luminance changes caused by residual DC components and leakage currents, leading to reduced luminance and increased power consumption.
Innovation Solution
A display device with a driving frequency converter circuit, common voltage controller, and common voltage generator that adjusts the common voltage to have an inclined waveform within an integer multiple of a frame period, minimizing flickering by compensating for data voltage ripples and maintaining a consistent voltage difference between data and common voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the display panel is driven at a low frequency to reduce power consumption, then power consumption is reduced, but luminance decreases and flickering increases due to residual DC components and leakage current
Solution Approach 1:
The patent applies parameter changes by adjusting the common voltage level dynamically based on the driving frequency. When operating at low frequencies, the common voltage is increased to compensate for the voltage drop caused by leakage current and residual DC components, thereby maintaining stable luminance while preserving the low power consumption benefit
Solution Approach 2:
The patent implements preliminary action by proactively adjusting the common voltage before significant luminance degradation occurs. The system detects the driving frequency and pre-compensates the common voltage to counteract the expected voltage drop from leakage current, preventing flickering before it becomes noticeable
2Use of energy by moving object
If the display panel is driven at a low frequency to maintain still images, then power consumption is reduced, but flickering occurs due to sudden luminance changes when data is refreshed
Solution Approach 1:
The patent changes the common voltage parameter dynamically according to the driving frequency. At low frequencies where flickering is problematic, the system increases the common voltage to maintain a stable voltage difference between data and common voltage lines, thereby eliminating luminance fluctuations and flickering while maintaining the energy-efficient low-frequency operation
Solution Approach 2:
The patent implements a feedback mechanism where the system continuously monitors the driving frequency and adjusts the common voltage accordingly. This closed-loop control ensures that the common voltage is optimized for each operating condition, preventing flickering by maintaining consistent voltage differential even as operating parameters change
3Stability of the object's composition
If the common voltage is increased to compensate for leakage current, then luminance stability is improved, but power consumption increases
Solution Approach 1:
The patent applies dynamics by making the common voltage adjustable and adaptive rather than fixed. The system dynamically modifies the common voltage level based on the actual driving frequency and operating conditions, increasing it only when necessary to compensate for leakage current at low frequencies, while maintaining lower voltage levels at higher frequencies where leakage is less problematic, thus balancing luminance stability with power consumption
Data Source
AI summary
A display device includes: a display panel; a driving frequency converter circuit configured to convert a driving frequency according to an input image data. A common voltage controller outputs a common voltage data corresponding to the driving frequency; and a common voltage generator receives the common voltage data to generate a common voltage and outputs the common voltage to the display panel. The common voltage has an inclined waveform within an integer multiple of a frame period.