Touchscreen Controller Idle Time Uplink Signal Transmission
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Solution Overview
Problem
Display flicker occurs in OLED touchscreen devices due to interference between uplink signals transmitted by the touchscreen controller and control signals/image data, particularly when communicating with an active stylus pen, as they share a common ground with the display driver.
Innovation Solution
A method where the touchscreen controller determines the presence of idle time in a display frame based on the frequency of the vertical synchronization signal (Vsync) and transmits uplink signals during this idle time to minimize interference, and when an active stylus pen is detected, it transmits uplink signals with opposite polarities from specific regions of the touch sensing layer to reduce flicker.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If uplink signals are transmitted by the touchscreen controller for communication with an active stylus pen, then communication functionality is improved, but display flicker occurs due to interference with control signals and image data
Solution Approach 1:
The patent segments the display frame into distinct time periods: active display periods for transmitting control signals and image data, and idle periods for transmitting uplink signals. This temporal segmentation allows different signal types to coexist without interference, resolving the contradiction between communication functionality and display stability.
Solution Approach 2:
The patent implements periodic transmission of uplink signals during idle periods of the display frame. By synchronizing uplink signal transmission with the periodic idle periods of the display refresh cycle, the system enables continuous communication functionality while preventing display flicker caused by simultaneous signal interference.
2Speed
If uplink signals are transmitted during active display periods, then communication speed is improved, but interference with control signals and image data causes display flicker
Solution Approach 1:
The patent extracts uplink signal transmission from the active display periods and relocates it to idle periods. This separation removes the harmful interaction between uplink signals and control signals/image data, eliminating display flicker while maintaining communication functionality through the dedicated idle time slots.
3Device complexity
If the touchscreen controller and display driver share a common ground, then device complexity is reduced, but uplink signals interfere with control signals and image data transmitted by the display driver
Solution Approach 1:
The patent introduces dynamic time-division multiplexing into the signal transmission scheme. By dynamically allocating different time periods within each display frame for different signal types (control signals during active periods, uplink signals during idle periods), the system maintains the simple common ground configuration while preventing signal interference through temporal separation.
Data Source
AI summary
A method for operating an electronic device includes a touchscreen controller determining based on a frequency of a vertical synchronization signal (Vsync), whether a first display frame includes an idle time, the idle time being a duration of time remaining in the first display frame after an image displayed on a display of the electronic device is updated during the first display frame. The method further includes in response to determining that the first display frame includes the idle time, the touchscreen controller transmitting an uplink signal in the first display frame, the uplink signal being transmitted during the idle time of the first display frame.