Touch Panel Electrode Separation Optimizes Capacitance and Signal
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Solution Overview
Problem
High performance touch panel sensors face challenges in balancing mutual capacitance and output signal magnitude, with existing designs either leading to electrical interference or reduced visibility and signal strength due to varying electrode separation distances.
Innovation Solution
A touch electrode configuration with an opaque metal mesh, where the electrode separation distance is optimized between 30 μm to 50 μm, or 0.5 to 0.75 times the pixel pitch, with inactive electrodes and a uniform insulating region, to reduce mutual capacitance while maintaining sufficient output signal magnitude and avoiding visibility issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If electrode separation distance is increased to reduce mutual capacitance, then mutual capacitance decreases, but output signal magnitude also decreases
Solution Approach 1:
The patent applies parameter changes by optimizing the electrode separation distance to a specific range (0.5 to 0.75 times the pixel pitch, or 30 to 50 μm). This parameter optimization achieves a disproportionate reduction in mutual capacitance while maintaining sufficient output signal magnitude, resolving the contradiction between reducing mutual capacitance and preserving signal strength.
2Ease of manufacture
If non-uniform insulating region is used to simplify manufacturing, then manufacturing complexity decreases, but electrode separation distance varies causing performance inconsistency
Solution Approach 1:
The patent applies homogeneity by requiring the insulating region to have uniform thickness throughout. This ensures consistent electrode separation distance across the entire touch panel, which maintains performance uniformity while still allowing for practical manufacturing through standard deposition processes.
3Reliability
If opaque metal mesh is used for high conductivity, then electrical performance improves, but visibility and display emission are interfered with
Solution Approach 1:
The patent applies dimensionality change by positioning the opaque metal mesh electrode configuration in a specific spatial relationship to the display pixels. The electrodes are arranged outside of the pixel regions that emit light, effectively moving the conductive elements to a different spatial dimension where they provide electrical performance without interfering with light emission from the pixel regions.
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 achieves a disproportionate reduction in mutual capacitance with minimal impact on output signal magnitude, optimizing for lower mutual capacitance and visibility, thus enhancing touch panel performance without interference with display emission.
Implementation Method 1
a first electrode and a second electrode that are separated by an insulating region that electrically isolates the first electrode from the second electrode
Implementation Method 2
A changing voltage or excitation electrical signal is applied to the drive electrode 20 from a voltage source 22. An output signal is then generated on an electrode different from the drive electrode, referred to as the sense electrode, such as on the adjacent electrode 21 by capacitive coupling. As a result, a mutual coupling capacitance 23 is formed between the drive electrode 20 and sense electrode 21.
Data Source
AI summary
A touch panel display includes a display panel having a plurality of pixel regions that emit light, and a touch sensor having an electrode configuration that overlays the display panel. The electrode configuration includes a first electrode and a second electrode that are separated by an insulating region. The electrode separation distance between the first and second electrodes is in a range whereby (1) with increasing electrode separation distance a first rate of proportional decrease in mutual capacitance between the first and second electrodes is greater than a second rate of proportional decrease in signal magnitude of an output signal, and (2) a ratio (R) of the first rate to the second rate satisfies the relationship 1.0<R<2.5. With such parameters, the electrode separation distance may be from 30 μm to 50 μm, and/or from 0.5 to 0.75 times a pixel pitch of the pixel regions.