Capacitive Touch Sensor Oblique Electrode Matrix
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Solution Overview
Problem
Capacitive touch sensors in large format displays face challenges in minimizing visual perceptibility, leading to limitations in their adoption and development due to issues like electrode occlusion, artifacts, and reduced frame rates caused by high electrical resistance in transparent conductive oxides.
Innovation Solution
The use of a zigzag structured electrode matrix with column and row conductors that oscillate across their respective axes, maximizing the distance between electrodes and reducing occlusion artifacts, while maintaining conductivity through the inclusion of inter-column and inter-row pseudo jumpers to minimize perceptibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If opaque metallic conductor is used for column and row electrodes oriented vertically and horizontally, then touch sensing capability is achieved, but visual occlusion and artifact formation occur
Solution Approach 1:
The patent applies asymmetry by rotating the column and row electrodes to non-orthogonal orientations (e.g., 30 degrees from vertical/horizontal). This asymmetric arrangement breaks the alignment with underlying LCD pixel rows and columns, thereby reducing the formation of moire artifacts and visual occlusion while preserving capacitive touch sensing functionality.
Solution Approach 2:
The patent introduces a rotational dimension to the electrode orientation problem. Instead of only varying electrode positions in the horizontal and vertical dimensions, the solution rotates the entire electrode matrix by an angle theta, adding a rotational degree of freedom that effectively reduces visual artifacts without compromising touch sensing.
2Object-affected harmful factors
If transparent conductive oxide (TCO) is used to reduce visual perceptibility, then visual occlusion is minimized, but electrical resistance increases and frame rate is limited
Solution Approach 1:
The patent changes the material parameter from transparent conductive oxide (TCO) to opaque metallic conductor. This parameter change enables the use of highly conductive materials like aluminum or copper, which achieve the required frame rates for large format displays, while the visual occlusion issue is simultaneously addressed through rotational orientation of the electrodes.
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 solution effectively reduces the visual impact of the electrode matrix, enhancing the user experience by minimizing occlusion artifacts and maintaining high touch sensing quality and frame rates in large format displays.
Implementation Method 1
a matrix of column and row electrodes positioned therebetween and configured to detect touch input based on changes in capacitance
Data Source
AI summary
Electrode matrices for capacitive touch-sensing are provided. An electrode matrix may include a plurality of column conductors having a first end and a second end formed along a central longitudinal axis. The column conductor may further include a column zigzag structure extending between the first end and the second end. The electrode matrix may further include a plurality of row conductors having a first end and a second end formed along a lateral axis. The row conductor may further include a row zigzag structure extending between the first end and second end. The zigzag structure of each of the plurality of column conductors may cross the zigzag structure of each of the plurality of row conductors in respective crossing regions that are formed at an intersection of the longitudinal axis of each column conductor and lateral axis of each row conductor.