Display Timing Controller Adjusts Emission Signal for High-Speed Driving
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Solution Overview
Problem
High-speed driving of display devices at frequencies like 120 Hz poses a challenge in maintaining the threshold voltage charge time for driving transistors, leading to reduced image quality due to shortened charge times.
Innovation Solution
A display device configuration that includes a timing controller adjusting the emission start signal period and clock signal cycle based on driving frequency, along with separate emission drivers providing a second emission control signal to effectively compensate the threshold voltage of driving transistors using a constant voltage source or data voltage, ensuring sufficient compensation time even at high speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the driving frequency is increased to achieve high-speed driving, then the productivity is improved, but the threshold voltage charge time is shortened leading to reduced image quality
Solution Approach 1:
The emission start signal period is dynamically adjusted based on the driving frequency. When operating at high driving frequencies (e.g., 120 Hz), the timing controller increases the emission start signal period to ensure that the threshold voltage charge time remains sufficient, thereby maintaining image quality while enabling high-speed driving operation
Solution Approach 2:
The patent changes the timing parameters of control signals to resolve the contradiction. Specifically, the emission start signal period is extended when driving frequency increases, and the clock signal cycle is adjusted accordingly. This parameter adjustment ensures that threshold voltage compensation is completed within the available time, preventing image quality degradation at high speeds
2Manufacturing precision
If the emission start signal period is increased to maintain threshold voltage charge time, then the image quality is maintained, but the supply period of emission control signal becomes longer
Solution Approach 1:
The timing controller performs preliminary adjustment of the emission start signal period before the actual emission phase. By extending the emission start signal period in advance when high driving frequency is detected, the system ensures that threshold voltage compensation is completed before emission begins, thereby maintaining image quality without unnecessarily extending the actual emission control signal supply period during the emission phase
3Reliability
If the clock signal cycle is adjusted to maintain compensation time, then the threshold voltage compensation is effective, but the device complexity increases
Solution Approach 1:
The timing controller performs multiple functions: it generates the emission start signal, adjusts the clock signal cycle, and controls the overall timing coordination between scan drivers and emission drivers. By making the timing controller universal and adaptable to different driving frequencies through software or firmware configuration, the patent avoids adding separate dedicated hardware circuits for frequency adaptation, thereby maintaining reliability while minimizing device complexity
Data Source
AI summary
A display device includes a display panel including a plurality of pixels, a timing controller which generates an emission start signal, an emission driver which supplies an emission control signal to the plurality of pixels based on the emission start signal received from the timing controller, a first scan driver which supplies a first scan signal to the plurality of pixels, a second scan driver which supplies a second scan signal to the plurality of pixels, and a data driver which supplies a data signal to the plurality of pixels. The timing controller adjusts a period in which the emission start signal is supplied based on a change of a driving frequency.