Capacitive Touchpad LED Layout Without Electrode Shielding
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Solution Overview
Problem
Conventional capacitive touchpads with multiple LED dies arranged on lateral portions suffer from a negative impact on touch control effect due to the presence of these LED dies.
Innovation Solution
A capacitive touchpad design that includes a substrate module, a sensing electrode layer, a driving electrode layer, a plurality of LED dies, and a controller, where the LED dies are arranged in distribution spaces without shielding any sensing electrodes, allowing the controller to drive the LED dies to emit light in response to coupling capacitors generated by conductors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple LED dies are arranged on lateral portions of the touchpad, then the light emission function is improved, but the touch control effect is negatively affected due to interference from LED die positions
Solution Approach 1:
The patent transitions from a two-dimensional planar arrangement of LED dies to a three-dimensional distributed arrangement within a depth space. LED dies are positioned at different depths and lateral locations within the touchpad structure, creating a volumetric distribution that separates the light emission function from the touch sensing plane, thereby eliminating interference while maintaining illumination.
Solution Approach 2:
The touchpad is divided into multiple functional zones: a touch sensing region with sensing electrodes, and a light emission region with distributed LED dies. The LED dies are segmented and placed in distribution spaces away from the sensing electrodes, allowing independent optimization of touch control and light emission functions without mutual interference.
2Length of stationary object
If LED dies are arranged close to sensing electrodes for compact design, then device thickness is reduced, but touch sensing precision deteriorates due to shielding effects
Solution Approach 1:
The patent utilizes the depth dimension to separate LED dies from sensing electrodes. Instead of arranging components only on the surface plane, LED dies are positioned within the thickness of the touchpad at optimized depths, creating a three-dimensional layout that maintains compact overall thickness while preventing shielding of the sensing electrodes.
Solution Approach 2:
Different regions of the touchpad have different component densities and arrangements. The sensing region maintains high electrode density for precise touch detection, while the light emission region distributes LED dies in specific patterns. The local arrangement of LED dies is optimized to provide illumination without interfering with the local touch sensing performance.
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 design enhances the touch control effect by avoiding interference from the LED dies' positions and allows for subtle changes in optical performance, while also potentially reducing the thickness of the touchpad and simplifying the manufacturing of the protective layer.
Implementation Method 1
When a coupling capacitor is generated from a conductor to at least one of the sensing electrodes
Implementation Method 2
the controller is configured to drive at least one of the LED dies adjacent to the at least one of the sensing electrodes to emit light
Data Source
AI summary
A capacitive touchpad is provided, which includes a substrate module, a plurality of sensing electrodes, a plurality of driving electrodes and a plurality of light-emitting diode (LED) dies. The plurality of sensing electrodes and the plurality of driving electrodes form a touch sensing region of the capacitive touchpad, and the touch sensing region is divided into a plurality of sensing units having same areas. Each of the LED dies is arranged in two adjacent ones of the plurality of sensing units, and a position of each of the LED dies corresponds to one of the plurality of driving electrodes, and the LED dies are electrically isolated from the plurality of sensing electrodes and the plurality of driving electrodes.