Source Driver Touch Transmitter Parallel Display Drive
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Solution Overview
Problem
Proximity sensor devices face hardware conflicts and signal interference when operating in both display updating and input sensing modes simultaneously, limiting the time available for each function.
Innovation Solution
A processing system with a driver module, receiver module, and determination module that allows for simultaneous display updating and input sensing by modulating the common electrode between voltages while maintaining a consistent potential difference with the source line, enabling concurrent input sensing and display updating without interfering with display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If electrodes are operated for input sensing while simultaneously updating the display, then the time available for both functions is increased, but display artifacts are produced due to hardware conflicts and signal interference
Solution Approach 1:
The patent applies periodic action by modulating the common electrode voltage at a specific frequency (e.g., 1/3 of the display refresh rate) during display updating periods. This periodic modulation enables capacitive sensing to occur concurrently with display updates without causing visible artifacts, as the sensing signal frequency is deliberately chosen to be subharmonic to the display refresh rate, preventing interference patterns from becoming visible to users.
Solution Approach 2:
The patent changes voltage parameters dynamically by modulating the common electrode between different voltage levels (e.g., Vcom and Vcom+ΔV) during display updating. This parameter change approach allows the system to encode sensing information within the display voltage waveform itself, enabling simultaneous operation of both display and sensing functions without requiring separate time periods.
2Object-affected harmful factors
If electrodes are operated in separate dedicated time periods for display updating and input sensing, then display quality is maintained, but the time available for input sensing is greatly reduced
Solution Approach 1:
The patent merges the display updating and input sensing operations into the same time period by utilizing the common electrode for both purposes simultaneously. The common electrode voltage waveform is designed to serve dual functions: maintaining display quality while encoding capacitive sensing information through periodic modulation, thereby eliminating the need for separate dedicated time periods for each function.
Solution Approach 2:
The patent makes the common electrode multi-functional by using it for both display updating and capacitive sensing concurrently. The same electrode structure and voltage control mechanism serve dual purposes: driving the display and transmitting sensing signals, thereby maximizing the utilization of available time and hardware resources without compromising either function.
3Loss of time
If the time allotted for display updating is reduced to increase input sensing time, then more time is available for input sensing, but display updating cannot be performed below a specified level
Solution Approach 1:
The patent uses periodic modulation of the common electrode at frequencies that are subharmonic to the display refresh rate, allowing sensing operations to occur during the display updating period without interfering with the minimum required display update time. This approach enables sensing to proceed concurrently while maintaining the display update timing at or above the specified minimum level.
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 approach significantly increases the time available for both input sensing and display updating, avoiding dedicated separate time periods and maintaining display quality.
Implementation Method 1
drive the first common electrode for capacitive sensing by modulating the first common electrode between a second voltage and a third voltage
Implementation Method 2
shift the first voltage driven onto the first source line while the first common electrode is modulated between the second voltage and the third voltage by a value about equal to a difference between the second voltage and the third voltage
Data Source
AI summary
Various embodiments enable driving one or more sub-pixels with a source voltage while concurrently modulating the voltage of one or more common electrodes coupled to the sub-pixels to perform input sensing with the common electrodes. The voltage driven onto the sub-pixel may be shifted while the common electrode is modulated by a value about equal to about the amplitude of the modulation applied to the common electrode. Thus, the potential difference between the source line and common electrode remains substantially unchanged so that display asperities are not introduced while input sensing while concurrently updating a sub-pixel with display information. Thus, the common electrode(s) may be modulated for input sensing without interfering with display updating of the one or more sub-pixels, greatly increasing the amount of time available for performing input sensing and/or display updating.