Touch Sensor Multiplexing for Display Circuit Size Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As display devices increase in size, the number of touch electrodes and touch driving signals required for touch sensors also increases, leading to a larger touch drive circuit size, which in turn raises manufacturing costs and thickness concerns.
Innovation Solution
A display apparatus with a substrate featuring a display area, a pad area, and a circuit area including multiplexer circuits that selectively connect touch electrode lines to reduce the number of touch wirings needed, incorporating organic films and wirings with contact holes to connect touch electrodes efficiently, thereby minimizing the touch drive circuit size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the display device size increases, then the display area is enlarged, but the number of touch electrodes and touch driving signals increases, leading to larger touch drive circuit size
Solution Approach 1:
The touch electrode lines are divided into multiple groups, with each group connected to a separate multiplexer circuit. This segmentation allows multiple touch electrodes to share common touch wirings through selective connection, reducing the total number of touch wirings and drive circuit components needed for large displays.
Solution Approach 2:
The multiplexer circuits enable touch wirings to serve multiple functions by selectively connecting to different touch electrode lines based on control signals. A single touch wiring can serve multiple touch electrodes at different times, reducing the overall wiring count and drive circuit size while maintaining full touch functionality across the enlarged display area.
2Adaptability or versatility
If more touch driving signals are output to sense touches at various points, then touch sensing capability is improved, but the touch drive circuit size increases
Solution Approach 1:
The multiplexer circuits dynamically reconfigure connections between touch wirings and touch electrode lines based on control signals. This dynamic switching allows the same physical wiring to be reassigned to different touch electrodes for different sensing operations, enabling comprehensive touch detection with fewer permanent connections and less circuitry.
Solution Approach 2:
The touch sensing system uses periodic multiplexing where different groups of touch electrodes are sensed in sequential time slots through the multiplexer circuits. This periodic switching allows multiple touch zones to be monitored using the same physical wirings at different times, maintaining full touch sensing capability while reducing the number of simultaneous signal paths required.
3Device complexity
If the number of touch wirings is reduced by using multiplexer circuits, then touch drive circuit size is reduced, but the thickness of the touch sensor increases
Solution Approach 1:
The patent transitions from a planar two-dimensional wiring layout to a three-dimensional stacked architecture where multiplexer circuits are positioned vertically above touch electrode lines. This vertical stacking in the thickness dimension allows wiring reduction in the horizontal plane while accommodating the additional circuit layers vertically, thus reducing touch drive circuit size without significantly increasing overall sensor thickness.
Data Source
AI summary
A display apparatus includes a substrate; a display area defined on the substrate and on which a plurality of pixels are disposed; a pad area defined on the substrate and on which a plurality of pads are disposed; a circuit area including a plurality of multiplexer circuits disposed between the display area and the pad area; a touch sensor part including a plurality of touch electrodes disposed at the display area; a plurality of touch electrode lines connecting the plurality of touch electrodes and the plurality of multiplexer circuits; and a touch wiring connecting the plurality of multiplexer circuits and the plurality of pads, wherein the plurality of multiplexer circuits selectively connects a touch electrode line among the plurality of touch electrode lines with the touch wiring.