Touch Sensor Demultiplexer Layout for Reduced Driving Pad Count
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Solution Overview
Problem
Existing touch sensors require a number of driving pads equal to the number of touch electrodes, leading to increased dead space and inefficiency in display devices.
Innovation Solution
The use of demultiplexers to reduce the number of driving pads by time-divisionally connecting touch electrodes to a fewer number of pads, with different electrode groups connected during different periods and controlled by specific control signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the number of driving pads is reduced using demultiplexers, then dead space is reduced and efficiency is improved, but device complexity increases due to additional demultiplexer components
Solution Approach 1:
Multiple electrode groups are merged into a single driving pad through the use of demultiplexers. The demultiplexer circuit integrates multiple input signals from different electrode groups and routes them to a single output pad, thereby reducing the total number of pads required and minimizing dead space in the display device.
Solution Approach 2:
A single driving pad is designed to serve multiple electrode groups through time-divisional control via demultiplexers. The same physical pad can sequentially connect to different electrode groups based on control signals, allowing one pad to perform the function of multiple pads and reducing overall pad count.
2Quantity of substance
If demultiplexers are used to connect multiple electrode groups to fewer pads, then the number of pads is minimized, but circuit complexity increases
Solution Approach 1:
The demultiplexer operates by periodically switching connections between electrode groups and the driving pad based on time-divisional control signals. Each electrode group is connected to the pad in sequential time periods, allowing multiple groups to share a single pad through periodic connection and disconnection controlled by timing signals.
Solution Approach 2:
The demultiplexer acts as an intermediary circuit between the electrode groups and the driving pad. It mediates the connection by receiving signals from multiple electrode groups and selectively routing them to the single driving pad, thereby reducing pad count while managing the complexity through a dedicated intermediate component.
Data Source
AI summary
A touch sensor may include a substrate and may include electrode units, first demultiplexers, second demultiplexers, and driving pads all located on the substrate. The electrode units each may include a plurality of electrode groups, the electrode groups each including a plurality of touch electrodes. The first demultiplexers each may include a plurality of sub-demultiplexers and each may be electrically connected to a corresponding one of the electrode units. Each of the sub-demultiplexers of a first demultiplexer may be electrically connected to a corresponding one of the electrode groups of a corresponding electrode unit. The second demultiplexers may be connected between the first demultiplexers and the driving pads.