Display Drive Circuit Clock Signal Pulse Width Extension
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Solution Overview
Problem
In display devices with integrated touch panels, the simultaneous operation of display drive and touch detection can lead to a deterioration in image quality due to signal interference, particularly during intermittent scanning operations, where the restart of display drive after interruption results in reduced luminance and potential voltage issues.
Innovation Solution
A display drive circuit that alternates between display drive and interruption periods, with a gate control driver extending the pulse width and amplitude of the clock signal during the start of the display drive period after interruption, and utilizing registers to adjust the gate pulse change period and clock signal parameters, ensuring adequate voltage recovery and minimizing image quality degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If display drive is performed simultaneously with touch detection, then productivity is improved, but image quality deteriorates due to signal interference
Solution Approach 1:
The display drive operation is divided into multiple scanning periods within one frame period, with touch detection performed in specific intervals. This segmentation allows both display driving and touch detection to be executed without simultaneous interference, maintaining image quality while achieving productivity improvement through time-division multiplexing.
2Object-affected harmful factors
If intermittent scanning is used for touch detection, then image quality is improved by preventing signal mixing, but luminance deteriorates at the start of display drive period
Solution Approach 1:
A preparation period is set before the display drive period during which the gate drive circuit is activated and voltage is gradually built up. This preliminary action ensures that when the display drive period starts, the gate drive circuit is already at appropriate voltage levels, preventing luminance deterioration at the beginning of scanning.
Solution Approach 2:
The gate control driver changes the pulse width of the clock signal during the gate pulse change period, extending it relative to the normal display drive period. This parameter change allows adequate voltage buildup in the gate drive circuit during the preparation period, ensuring proper luminance when display driving commences after interruption.
3Illumination intensity
If the clock signal pulse width is extended during start of display drive period, then luminance is improved, but device complexity increases
Solution Approach 1:
The gate control driver is designed to perform multiple functions: normal clock signal generation during display drive, and extended pulse width generation during the gate pulse change period. This multi-functionality allows the same circuit to handle both standard and special timing requirements without adding separate dedicated circuits, thereby limiting the increase in device complexity.
Data Source
AI summary
Provided is a display drive circuit which is connected to a display panel including a gate drive circuit that scans gate electrodes, a source driver that drives source electrodes of the display panel, and a gate control driver that supplies a clock signal to the gate drive circuit. The display drive circuit performs an intermittent operation which is alternately provided with a display period in which the source electrodes are driven and an interruption period during which the display panel is not updated. During a start of the display period following the interruption period, the gate control driver extends a pulse width of the clock signal which is supplied to the gate drive circuit, or preliminarily outputs the clock signal before the start of the display period.