Touch Display Controller Noise Isolation via Dynamic Timing
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Solution Overview
Problem
Noise interference between the display panel and touch panel in portable information terminal devices causes unwanted brightness differences and flicker due to capacitive coupling, especially when touch detection occurs during display periods.
Innovation Solution
A touch display controller that dynamically adjusts the start timings of display and non-display periods within a frame cycle, allowing touch panel activation and detection to occur during non-display periods, thereby isolating noise sources and minimizing brightness differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If touch detection is performed during the display period, then touch response speed is improved, but noise interference between display panel and touch panel increases
Solution Approach 1:
The frame cycle is segmented into distinct display period and non-display period, with touch detection performed during the non-display period. This temporal segmentation separates the noise-generating display operations from the sensitive touch detection operations, eliminating noise interference while maintaining functional performance.
Solution Approach 2:
The controller dynamically adjusts the timing of display and non-display periods within the frame cycle to optimize the separation between display operations and touch detection. This dynamic timing adjustment allows flexible management of noise isolation while ensuring touch response within acceptable timeframes.
2Object-affected harmful factors
If non-display period is extended to improve touch detection, then noise isolation is improved, but brightness uniformity deteriorates
Solution Approach 1:
The controller dynamically adjusts the length and positioning of non-display periods to achieve optimal noise isolation while maintaining brightness uniformity. By flexibly managing timing parameters, the system prevents fixed brightness differences that would occur with rigid, extended non-display periods.
Solution Approach 2:
The controller changes timing parameters of display and non-display periods to balance noise isolation requirements with brightness uniformity. By adjusting these parameters dynamically, the system achieves noise separation without creating visible brightness variations across the display frame.
3Device complexity
If display and non-display period timings are fixed, then control simplicity is maintained, but noise interference and brightness differences increase
Solution Approach 1:
The controller implements dynamic adjustment of display and non-display period timings to eliminate noise interference and brightness differences. This dynamic control mechanism, while adding some complexity, effectively resolves the technical problems by adapting timing parameters to optimize performance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution effectively suppresses noise interference and reduces unwanted brightness differences, improving both display quality and touch detection performance by ensuring that noise from activation and detection do not coincide, and reducing flicker visibility.
Implementation Method 1
A mutual capacitance type touch panel which supports multipoint touch has a number of detection capacitances formed at intersections where the drive and detection electrodes intersect one another like a matrix
Implementation Method 2
the capacitive coupling between a display panel and a touch panel superposed on each other or integrally formed
Implementation Method 3
a liquid crystal panel has a thin-film transistor referred to as TFT arranged at each intersection point of the scan and signal electrodes
Implementation Method 4
The signal voltages supplied to the source electrodes at this time are applied to the liquid crystal elements, thereby bringing them into a transmissive state
Data Source
AI summary
Provided are a touch display control device and an information terminal device, which are arranged so that the noise resulting from the actions for activation and display on a display panel, and the noise caused by the actions of activation and detection on a touch sensor never affects each other, and are useful for suppressing the elicitation of the difference in brightness attributed to non-display in a display frame.The information terminal device includes: a display controller operable to change start timings of display and non-display periods in a cycle of a frame synchronizing signal of a display frame, in each cycle of the frame synchronizing signal or each sequence of cycles thereof; and a touch panel controller operable to perform the activation of a touch panel and a touch detection during the non-display period.