Touch Sensor Bezel Dummy Electrodes for Edge Accuracy
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Solution Overview
Problem
Touch sensors integrated into liquid crystal display devices face challenges in maintaining accuracy and linearity, particularly at the edges and corners, due to variations in capacitance measurements which result in reduced touch sensitivity and performance.
Innovation Solution
The integration of a touch sensor system with a bezel area that extends beyond the active display area, featuring a network of gate and data lines, pixel electrodes, and routing wires, which form a horizontal electric field and compensate for capacitance changes at edges and corners, ensuring consistent touch performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a touch sensor is integrated into the display device, then touch sensitivity and ease of operation are improved, but touch accuracy at edges and corners deteriorates due to capacitance measurement variations
Solution Approach 1:
The patent applies local quality by differentiating the treatment of electrode regions based on their location. Dummy pixel electrodes are specifically added to bezel regions (edges and corners) while regular pixel electrodes are used in the active display area. This creates location-specific electrode configurations that compensate for the reduced capacitance measurements at edges and corners, thereby maintaining uniform touch accuracy across the entire display surface while preserving the integrated touch sensor benefits.
2Ease of manufacture
If the touch sensor uses standard pixel electrodes only in the active area, then manufacturing simplicity is improved, but touch performance at bezel regions deteriorates
Solution Approach 1:
The patent implements universality by making the dummy pixel electrodes in the bezel region serve multiple functions. These electrodes not only compensate for the reduced capacitance at edges and corners but also maintain the continuous electrode pattern required for proper liquid crystal switching across the entire panel. This multi-functional design allows the same electrode structure to address both touch sensitivity enhancement and display uniformity requirements without requiring separate compensation mechanisms.
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 configuration enhances touch accuracy and linearity by maintaining initial capacitances across the active and bezel areas, improving touch performance even at edges and corners.
Implementation Method 1
measure changes in a capacitance of each independent pattern, thereby deciding whether or not a touch operation is performed
Implementation Method 2
sense changes in voltages generated in sensing nodes defined as crossings of the X-axis electrode lines and the Y-axis electrode lines through the Y-axis electrode lines
Data Source
AI summary
A touch sensor integrated type display device includes gate lines and data lines disposed to cross over each other, pixel electrodes respectively disposed in areas defined by the crossing of the gate lines and the data lines in an active area, 1-1 electrodes arranged in at least two rows and at least two columns in the active area, 1-2 electrodes positioned outside the 1-1 electrodes and extending from the active area to a bezel area, and first routing wires respectively connected to the 1-1 and 1-2 electrodes and arranged in parallel. Each gate line extends from the active area to the bezel area on opposite sides of the active area, and each data line extends from the active area to the bezel area on opposite sides of the active area crossing the gate line.