Sensor Panel Guard Trace Geometry for Noise Blocking
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Solution Overview
Problem
Existing sensor panels fail to sufficiently block electromagnetic noise entering from outside, which can impact the accuracy of position detection using the differential method, especially when guard traces are extended along routing traces, leading to increased capacitance and inadequate common mode noise removal.
Innovation Solution
A sensor panel design with guard traces positioned strategically to maintain varying separation distances from routing traces, with a stepped configuration in regions adjacent to the detection area to effectively block electromagnetic noise without interfering with common mode noise removal, utilizing the metal frame and guard traces to absorb external noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a guard trace is extended along the routing traces to block electromagnetic noise, then electromagnetic noise blocking is improved, but the capacitance between the guard trace and routing traces increases, which deteriorates common mode noise removal
Solution Approach 1:
The guard trace configuration is made non-uniform by introducing a stepped portion at specific locations. This creates different separation distances between the guard trace and routing traces in different regions, allowing the system to optimize both electromagnetic noise blocking (where smaller distance helps) and common mode noise removal (where larger distance helps), thus resolving the contradiction through spatially varying local properties
2Ease of manufacture
If the routing traces and outermost shielding trace are positioned far apart, then routing is easier, but electromagnetic noise blocking becomes insufficient
Solution Approach 1:
Instead of only adjusting the lateral position of routing traces, the invention introduces a vertical dimension to the guard trace by creating stepped portions that extend in the direction perpendicular to the routing traces. This dimensional change allows the guard trace to provide effective noise blocking without requiring the routing traces to be positioned extremely close, thus maintaining manufacturing ease while improving noise blocking
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
The design effectively blocks electromagnetic noise entering from outside while maintaining the accuracy of common mode noise removal, enhancing the overall position detection performance without increasing the bezel region size.
Implementation Method 1
a guard trace extending and disposed on one side of the plurality of routing traces farther from the detection region compared with another side of the plurality of routing traces which is closer to the detection region
Implementation Method 2
reception signals at a plurality of electrodes are input into a differential amplifier, and the position of the finger or the active pen is determined on the basis of the reception level of an output signal of the differential amplifier. The position detecting device is configured in this manner to remove the effect of external noise, particularly, common mode noise
Data Source
AI summary
A sensor device comprises an integrated circuit and a sensor panel. The sensor panel includes: a plurality of first linear electrodes disposed in a detection region; a plurality of first routing traces; a plurality of first terminals disposed along one edge of the sensor panel parallel to a second direction; and a first guard trace extending and disposed on one side of the plurality of first routing traces farther away from the detection region. A first trace is one of the plurality of first routing traces connected to a first electrode that is a first linear electrode disposed farthest away from the plurality of first terminals among the plurality of first linear electrodes. A separation distance between the first trace and the first guard trace is not constant in the second direction in a first region adjacent to the detection region in the second direction. In the first region, the first guard trace has a portion intersecting a first direction.