Display Panel Scan Timing for Stable Luminance at Variable Frame Frequencies
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Solution Overview
Problem
Display devices experience luminance deviations due to variations in variable frame frequencies, leading to tearing phenomena and inconsistent image quality.
Innovation Solution
A display device operates with a panel driver that performs active scan operations during active periods and initialization scan operations during blank periods, adjusting the timing of initialization scan operations based on variable frame frequencies to maintain consistent luminance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the display panel operates at a variable frame frequency to prevent tearing, then adaptability is improved, but luminance deviation occurs due to inconsistent initialization timing
Solution Approach 1:
The patent applies dynamics by making the initialization scan operation timing flexible and adaptive to variable frame frequencies. The panel driver dynamically adjusts when to perform initialization scan operations based on the actual frame frequency, transforming a static timing system into a dynamic one that can adapt to different refresh rates while maintaining consistent luminance output
Solution Approach 2:
The patent changes the timing parameter of initialization scan operations to match variable frame frequencies. By adjusting the timing at which initialization scans occur based on the frame frequency, the system maintains consistent luminance characteristics across different operating conditions without requiring a fixed timing scheme
2Stability of the object's composition
If initialization scan operations are performed frequently to maintain luminance consistency, then luminance stability is improved, but the complexity of timing control increases
Solution Approach 1:
The patent simplifies timing control complexity by changing the approach from calculating multiple possible initialization timings to using a single clear criterion: perform initialization scan operations only during blank periods when the frame period exceeds the minimum frame period. This parameter change in the control logic reduces computational complexity while maintaining luminance stability
3Ease of operation
If the active period time length is kept constant to simplify control, then ease of operation is improved, but luminance deviation occurs at lower frame frequencies
Solution Approach 1:
The patent extracts the luminance consistency maintenance function from the active period and relocates it to the blank period through initialization scan operations. By separating these functions, the active period can remain simple and constant while the blank period handles the adaptive initialization needed for luminance consistency across different frame frequencies
Solution Approach 2:
The patent applies preliminary action by performing initialization scan operations during the blank period before the active period begins. This advance initialization ensures that pixels are properly prepared for the upcoming frame display, preventing luminance deviations that would otherwise occur at lower frame frequencies while keeping the active period simple
Data Source
AI summary
A display device includes: a display panel including a plurality of pixels; and a panel driver to drive the display panel at a variable frame frequency, and to: in an active period of a frame period, perform an active scan operation to initialize light emitting elements of the plurality of pixels, while providing data voltages to the plurality of pixels, and in a blank period of the frame period, perform an initialization scan operation to initialize the light emitting elements without providing the data voltages to the plurality of pixels. A time interval from a start time point of the frame period to a time point at which the initialization scan operation is performed is different from a time length of a minimum frame period corresponding to a maximum frame frequency of the variable frame frequency.