Display Device Subframe Timing for Low Gradation Control
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Solution Overview
Problem
Existing display devices face challenges in achieving fine gradation control on the low gradation side, particularly due to limitations in subframe period length and drive margin, which affects the expression of detailed gradations in light-emitting elements.
Innovation Solution
A display device with a control circuit that divides the frame period into subframe periods of varying lengths, using a combination of high and low current levels to control light emission and non-emission of light-emitting elements, allowing for precise gradation control by adjusting the length of light emission periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the subframe period length is kept equal for analog and digital gradation display, then the drive timing is simplified, but fine gradation expression on the low gradation side becomes difficult to achieve
Solution Approach 1:
The invention segments the frame period into multiple subframe periods with different lengths, specifically creating a first subframe period for analog gradation display and a second subframe period for digital gradation display. This segmentation allows each subframe period to be optimized independently: the first subframe period can be extended to provide sufficient drive margin for analog gradation control on the low gradation side, while the second subframe period maintains standard timing for digital display. The segmentation resolves the contradiction by enabling differentiated timing treatment for different display modes.
2Reliability
If the selection period in analog drive is set longer than in digital drive to secure drive margin, then the drive margin is improved, but the system complexity increases
Solution Approach 1:
The invention applies dynamics by making the subframe period length variable rather than fixed. The first subframe period for analog gradation display is set longer than the second subframe period for digital gradation display. This dynamic adjustment of timing parameters allows the system to secure adequate drive margin during analog drive operations without permanently increasing the overall frame period or complicating the display timing structure. The longer duration provides the necessary margin for precise current control in analog mode.
3Device complexity
If equal subframe periods are used, then the control logic is simplified, but low gradation control precision deteriorates
Solution Approach 1:
The invention applies local quality by assigning different temporal characteristics to different portions of the display cycle. The first subframe period dedicated to analog gradation display is given a longer duration to enable precise low gradation control, while the second subframe period for digital display maintains standard timing. This local differentiation ensures that the region requiring high precision (analog gradation control) receives adequate temporal resources without unnecessarily extending the entire frame period or complicating the overall control logic.
Data Source
AI summary
A display device includes a plurality of light-emitting elements, and a control circuit configured to control drive of the light-emitting elements. The control circuit divides one frame period into a plurality of subframe periods having different lengths and controls light emission and non-emission of the light-emitting elements for each of the subframe periods.