In-Cell Touch Display Device Using Time-Division Multiplexing
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Solution Overview
Problem
In large-screen touch display devices, the increased number of touch sensors and touch lines leads to reduced transmittance, larger source/touch driver sizes, and higher manufacturing costs due to the need for more input and output channels.
Innovation Solution
The touch display device divides touch sensors into odd and even sensors, using fewer touch lines and touch switches to drive them, with a timing controller generating switch control signals and a gate driver supplying switch enable signals to reduce the number of input/output channels and enhance transmittance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of touch sensors is increased to support large-screen high-resolution displays, then the touch sensing coverage and resolution are improved, but the number of touch lines increases, reducing transmittance and increasing device complexity
Solution Approach 1:
The patent segments the touch sensing function by dividing touch sensors into odd and even groups that operate in different time periods. Each group can be controlled by fewer touch lines through time-division multiplexing, reducing the total number of touch lines required while maintaining high-resolution touch sensing across the entire display area
Solution Approach 2:
The patent implements periodic action by alternately activating odd and even touch sensor groups in different time periods. During odd touch periods, odd sensors are activated; during even touch periods, even sensors are activated. This time-division approach allows the same touch lines to serve multiple sensors sequentially, reducing the number of simultaneous connections needed
2Reliability
If the number of touch lines is increased to connect all touch sensors, then the touch sensing capability is improved, but the transmittance of the display is reduced
Solution Approach 1:
By segmenting touch sensors into odd and even groups that are activated at different times, the patent reduces the number of touch lines needed at any given moment. This segmentation allows the same physical touch lines to be reused for different sensor groups in different time periods, thereby reducing the total number of touch line connections and improving light transmittance
Solution Approach 2:
The periodic activation of odd and even touch sensor groups allows the system to maintain full touch sensing capability while using fewer simultaneous touch line connections. During odd periods, odd sensors use a set of touch lines; during even periods, even sensors use the same or different touch lines. This temporal separation reduces the number of permanently routed touch lines, improving display transmittance
3Area of stationary object
If the number of input and output channels of source/touch driving ICs is increased to support more touch lines, then the touch sensor coverage is improved, but the size of the source/touch driver is enlarged and manufacturing cost increases
Solution Approach 1:
The patent reduces the number of input/output channels required in the source/touch driving IC by implementing periodic control of touch switches. Instead of providing separate continuous control signals for all touch sensors, the system uses time-multiplexed control where touch switches are activated in sequences during odd and even touch periods. This temporal multiplexing allows fewer control channels to manage a larger number of touch sensors
Solution Approach 2:
By segmenting the control approach into periodic phases with different active sensor groups, the patent enables the source/touch driver to use fewer simultaneous output channels. The driving IC can reuse output channels for different sensor groups at different times, reducing the total number of I/O pins required while maintaining comprehensive touch sensor coverage
Data Source
AI summary
Disclosed are an in-cell touch type touch display device that includes a touch display panel, where a plurality of touch sensors are disposed, and a driving circuit unit. Each of the plurality of touch sensors are disposed to correspond to a plurality of subpixels, and each of the plurality of touch sensors may include one or more touch switches. The one or more touch switches disposed in each of the plurality of touch sensors divisionally drive the plurality of touch sensors by 1/n (where n is a natural number equal to or more than two).