Optical Pressure Sensing via Circuit Board Deflection
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Solution Overview
Problem
Conventional pressure sensing systems, such as touch pads, suffer from accuracy issues due to the elasticity of flexible layers which can offset pressure and vary in recovery speed, leading to inaccurate pressure detection.
Innovation Solution
A pressure sensing system utilizing a circuit board, a case, light emitters, and photo detectors, where the distance between the circuit board and the case decreases under pressure, increasing the intensity of light detected by the photo detectors, allowing for precise pressure sensing through optical paths instead of conventional flexible layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a flexible layer is used to transfer pressure from the touching layer to the circuit layer, then pressure sensing function is achieved, but the elasticity of the flexible layer offsets part of the pressure and causes accuracy problems
Solution Approach 1:
The patent removes the flexible layer from the pressure sensing system. Instead of using a flexible layer to transfer pressure, the invention directly applies pressure to the circuit board, eliminating the source of elastic interference and improving measurement accuracy.
Solution Approach 2:
The patent replaces the mechanical flexible layer-based pressure transfer mechanism with a direct mechanical pressure application system. The circuit board itself serves as the pressure reception element, eliminating the intermediate flexible component that caused accuracy degradation.
2Speed
If the flexible layer is pressed, then pressure is transferred to the circuit layer, but the recovery speed varies with pressure and time causing inaccuracy
Solution Approach 1:
The patent eliminates the flexible layer that exhibits variable recovery characteristics. By removing this component, the system avoids the time-dependent and pressure-dependent recovery behavior that compromised measurement accuracy.
Solution Approach 2:
Instead of using a flexible layer that recovers after pressing, the patent uses a rigid circuit board that maintains its deformed state under pressure, providing stable and accurate pressure measurement without recovery issues.
3Measurement precision
If conventional touch pad structure with touching layer and flexible layer is used, then pressure sensing is achieved, but accuracy problems occur due to elasticity offset
Solution Approach 1:
The patent simplifies the multi-layer touch pad structure by removing the flexible layer. The circuit board directly receives pressure, eliminating the complex layering and the associated accuracy problems caused by elastic deformation in intermediate layers.
Solution Approach 2:
The circuit board serves multiple functions: it provides structural support, receives pressure directly, and contains the pressure sensing circuitry. This multi-functionality eliminates the need for separate flexible layer components.
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 enables more accurate and sensitive pressure detection, improving the precision of pressure sensing in electronic devices by calculating the difference in light intensity before and after pressure application, allowing for more reliable execution of corresponding events or displays.
Implementation Method 1
Light emitted by the light emitters enters into the circuit board, and part of the light passes through the second passing zone to enter into the photo detector
Implementation Method 2
the photo detector is located on the second passing zone. Light emitted by the light emitters enters into the circuit board, and part of the light passes through the second passing zone to enter into the photo detector
Implementation Method 3
the circuit board has a top surface and a bottom surface. The case is located near the bottom surface of the circuit board; the distance between circuit board and the case decreases when the circuit board is subjected to a pressure
Data Source
AI summary
A pressure sensing system includes a circuit board, a case, a cover layer, a plurality of light emitters, and a photo detector. The circuit board has a top surface and a bottom surface. The case is located near the bottom surface of the circuit board. The distance between circuit board and the case decreases when the circuit board is subjected to a pressure. The cover layer covers a part of the top surface and a part of the bottom surface, wherein a part of the top surface which is not covered by the cover layer includes a plurality of first passing zone and a second passing zone, and a part of the bottom surface which is not covered by the cover layer includes a plurality of bottom passing zone. The light emitters are located on the first passing zone, respectively, and the photo detector is located on the second passing zone.