Touch Screen LED Photodiode Circuit Reduction
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Solution Overview
Problem
Existing touch screens using light emitting diodes (LEDs) and photodiodes for touch location detection require numerous electrical connections, increasing the size and cost of the circuit, which is inefficient and costly to manufacture.
Innovation Solution
The solution involves reducing the number of LED and photodiode connections to the circuit by electrically connecting multiple photodiodes in parallel and LEDs in series, thereby minimizing the number of connections needed to determine the touch location on the touch screen panel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple LEDs and photodiodes are individually connected to the circuit, then the touch detection accuracy is maintained, but the circuit size and manufacturing cost increase
Solution Approach 1:
The patent combines multiple photodiodes into groups where each group shares common electrical connections to the circuit. Specifically, multiple photodiodes are connected in parallel to shared signal lines, reducing the number of individual connections required while maintaining the ability to detect touch events across different locations on the touch screen.
Solution Approach 2:
The patent divides the touch screen into multiple zones or regions, with each zone served by a specific group of LEDs and photodiodes. This segmentation allows for localized touch detection while reducing the overall circuit complexity by treating each zone as an independent detection unit with its own shared connections.
2Reliability
If multiple LEDs and photodiodes are individually connected to the circuit, then the touch detection capability is maintained, but the manufacturing cost increases
Solution Approach 1:
The patent merges multiple photodiode connections into shared electrical pathways, reducing the total number of connection points that require manufacturing processes such as bonding wires or traces. This merging reduces material usage and assembly steps while maintaining functional reliability through the grouped detection architecture.
3Adaptability or versatility
If numerous electrical connections are made to LEDs and photodiodes, then the touch screen functionality is ensured, but the material costs increase
Solution Approach 1:
The patent combines multiple individual electrical connections into fewer shared connections by grouping photodiodes that detect touches in adjacent or related regions. This reduction in the quantity of electrical connection materials (such as conductive traces, bonding wires, or connection pads) directly reduces material costs while preserving the ability to detect touches across the entire touch screen surface.
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 configuration reduces the size and material costs of the circuit while maintaining the ability to accurately determine touch location, thereby providing a cost-effective and efficient touch detection system.
Implementation Method 1
The photodiodes convert this received light into electrical signals so that the location of the touch is determined
Implementation Method 2
A touch screen may utilize light emitting diodes (LEDs) and photodiodes to determine the location of a touch on a panel of the touch screen. Upon the LEDs are illuminated, the light emitted by these LEDs is received by the photodiodes
Data Source
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AI summary
Examples of a touch screen are disclosed herein. One example of the touch screen includes a plurality of light emitting diodes positioned adjacent a perimeter of a panel and a circuit electrically connected to the plurality of light emitting diodes to individually and sequentially illuminate the light emitting diodes. This example of the touch screen additionally includes a plurality of photodiodes positioned adjacent the perimeter of the panel so that each photodiode receives light from at least one of the light emitting diodes when illuminated by the circuit. Photodiodes that receive light from different light emitting diodes are electrically connected in parallel.