Alternating Concave Conductive Elements for Multi-Touch Sensor
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Solution Overview
Problem
Conventional touch sensors with a single conductive layer are unable to accurately determine the location of multiple simultaneous touches in two dimensions due to the arrangement of conductive elements, which limits their capability in detecting complex touch inputs.
Innovation Solution
A touch sensor with alternating, single-layer conductive elements of complementary, substantially concave shapes that fill the sensor area, allowing multiple elements to interact with each touch, coupled with a touch controller that calculates touch positions using weighted averages of adjacent element coordinates, enabling detection of multiple simultaneous touches in two dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single ITO layer is used in conventional touch sensors, then the device complexity is reduced, but the measurement precision for determining multiple simultaneous touches in two dimensions deteriorates
Solution Approach 1:
The single ITO layer is segmented into multiple discrete conductive elements arranged in a specific pattern. Each conductive element acts as an independent sensing unit, allowing the system to determine touch locations in two dimensions by measuring capacitance changes across multiple segmented elements, thereby maintaining simplicity while improving measurement precision.
Solution Approach 2:
The conductive elements are arranged in a two-dimensional grid pattern rather than a single continuous layer. This dimensional transformation allows the sensor to detect touches in both x and y directions simultaneously by comparing capacitance values across the array of conductive elements, enabling accurate multi-touch detection without increasing layer complexity.
2Measurement precision
If multiple ITO layers are used in conventional touch sensors, then the measurement precision for multiple simultaneous touches is improved, but the device complexity increases
Solution Approach 1:
Instead of using multiple continuous ITO layers, the invention segments a single ITO layer into multiple discrete conductive elements arranged in a two-dimensional array. This segmentation approach achieves multi-touch detection capability equivalent to multiple layers while maintaining the simplicity of a single-layer structure, reducing manufacturing complexity and alignment requirements.
3Ease of manufacture
If conventional conductive element arrangements are used, then the ease of manufacture is maintained, but the productivity in handling complex touch inputs deteriorates
Solution Approach 1:
The conductive elements are arranged in a two-dimensional grid pattern that covers the entire sensor surface. This two-dimensional arrangement allows the sensor to process complex touch inputs including multiple simultaneous touches, gestures, and pressure variations by measuring capacitance changes across the grid, significantly enhancing productivity in handling complex inputs while maintaining ease of manufacture through standard photolithography processes.
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 allows for accurate determination of touch positions in two dimensions, enhancing the capability of touch sensors to handle complex input scenarios with minimal error and increased precision.
Implementation Method 1
A capacitive touch sensor is coated with a conductive material, typically Indium Tin Oxide (ITO) or copper, which conducts continuous electrical current across a sensor. The sensor exhibits a precisely controlled field of stored charge in both the horizontal and vertical axes of a display to achieve capacitance.
Data Source
AI summary
A touch sensor includes conductive elements of substantially concave shape to enable detection of multiple simultaneous touches in at least two directions, with reduced noise sensitivity and enhanced accuracy. The shapes of the conductive elements may be similar, or may be alternating, complementary shapes that cover substantially all of the sensor area. The conductive elements physically interact with adjacent elements in such a way that the area covered by a touch changes monotonically from overlapping substantially all of one element to overlapping substantially all of an adjacent element as the touch area is moved from one element to the other element along a line between the centers of those adjacent elements. Such monotonic change of touch overlap area may occur simultaneously in two orthogonal directions. Connections from internally positioned conductive elements to a touch controller may be made to pass through other conductive elements.