Lighting Touchpad Cell Layout for Uniform Capacitance and Illumination
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Solution Overview
Problem
Existing capacitive touchpads face challenges in balancing light efficiency and ensuring uniform performance across all sensor units due to the integration of light-emitting devices.
Innovation Solution
A lighting touchpad design that includes a substrate with alternately arranged first and second electrodes and bonding pads, with lighting devices connected to these pads, and a sensing area with predetermined spatial characteristics to enhance uniformity and maintain consistent capacitance values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If light emitting devices are integrated within the touch sensor units, then lighting effects are achieved, but uniform performance across all sensor units deteriorates
Solution Approach 1:
The patent divides the touchpad into multiple sensing cells with segmented electrode arrangements. Each sensing cell contains first and second electrodes with bonding pads positioned at specific locations, creating modular units that maintain consistent electrical characteristics despite the presence of lighting devices. This segmentation allows independent optimization of each cell's lighting and sensing functions.
Solution Approach 2:
The patent implements local quality by positioning bonding pads at specific locations within each sensing cell, away from the center where lighting devices are located. The electrode patterns are designed with varying local characteristics - the first and second electrodes have different shapes and positions tailored to compensate for the local impact of lighting devices on capacitance values.
2Illumination intensity
If light emitting devices are integrated within the touch sensor units, then lighting effects are achieved, but light efficiency deteriorates
Solution Approach 1:
The patent transitions from a traditional planar electrode layout to a three-dimensional spatial arrangement where bonding pads are positioned at specific coordinates (e.g., corners or edges) of each sensing cell. This dimensional repositioning allows light to be emitted from the center while electrical connections are established at peripheral locations, reducing light obstruction and improving light efficiency.
3Measurement precision
If electrodes and bonding pads are arranged on the substrate, then capacitive sensing is enabled, but uniform capacitance values across sensing cells deteriorate
Solution Approach 1:
The patent employs asymmetric electrode designs where the first electrode and second electrode have different shapes, sizes, and positions within each sensing cell. The bonding pads are also asymmetrically positioned relative to the electrodes. This asymmetric arrangement compensates for the non-uniform impact of lighting devices, allowing each sensing cell to achieve consistent capacitance values despite physical asymmetries in the structure.
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 ensures uniform base capacitance and high sensing performance, improving touch sensing accuracy and reducing the impact of lighting devices on touch performance, while maintaining consistent lighting effects.
Implementation Method 1
light emitting diodes (LEDs) can be affixed to a printed circuit board (PCB)
Implementation Method 2
capacitive touchpads have been adapted for various applications that incorporate lighting effects
Data Source
AI summary
A lighting touchpad is provided. The lighting touchpad includes a substrate, a plurality of first electrodes, a plurality of second electrodes, a plurality of bonding pads and a plurality of lighting devices. The plurality of first electrodes, the plurality of second electrodes and the plurality of bonding pads are arranged on the substrate, and the first electrodes, the second electrodes, and the bonding pads are alternately arranged in a sensing area without overlapping with one another. The pluralities of lighting devices are connected to a part of the bonding pads. The sensing area includes a plurality of sensing cells, and the first electrodes, the second electrodes and the bonding pads are arranged according to a predetermined spatial characteristic for each of the sensing cells.