Force Sensing Bridge Resistor Layout for Temperature Compensation
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Solution Overview
Problem
Current touch control display panels face accuracy issues with force touch due to temperature changes caused by user interaction, as resistance measurements are affected by temperature variations, leading to reduced measurement accuracy.
Innovation Solution
The implementation of a force sensing bridge with resistors disposed in the same leg and confined to a small area on the touch control display panel, where resistors experience the same temperature, minimizing temperature effects and improving measurement accuracy by ensuring consistent local temperature across resistors in the same leg.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If force sensors are distributed across a large area to detect touch positions, then the coverage of touch detection is improved, but the temperature variation between sensors increases, reducing measurement accuracy
Solution Approach 1:
The force sensing bridge is divided into four independent sensing resistors (first, second, third, and fourth sensing resistors) arranged in specific configurations. Each resistor can be independently optimized for its local temperature conditions while contributing to the overall force measurement, allowing the system to maintain both wide coverage and high precision.
Solution Approach 2:
The patent applies different extending length configurations to different sensing resistors based on their local requirements. The first and third sensing resistors have longer extending lengths in the first extending direction, while the second and fourth sensing resistors have longer extending lengths in the second extending direction. This local optimization ensures that each resistor experiences minimal temperature variation while accurately detecting force in its specific direction.
2Measurement precision
If sensing resistors are placed in the same small area to experience the same temperature, then temperature-related measurement errors are reduced, but the detection area for force touch is limited
Solution Approach 1:
Instead of placing all sensing resistors in a single small area, the patent segments the force detection function into four distributed sensing resistors. Each resistor is positioned to detect force in a specific direction, and all resistors experience the same local temperature change when a user interacts with the panel, thereby maintaining measurement precision while expanding detection coverage.
Solution Approach 2:
The force sensing bridge circuit is designed to simultaneously detect force in multiple directions using the four sensing resistors. The circuit configuration allows it to universally measure force magnitude and direction while all resistors experience identical temperature conditions, achieving both precision and broad detection capability.
3Measurement precision
If the first and third sensing resistors have longer extending lengths in the first extending direction, then force detection sensitivity in the first direction is improved, but the resistance value increases, potentially affecting signal measurement
Solution Approach 1:
The patent employs asymmetric extending length configurations for different sensing resistors based on their functional requirements. The first and third sensing resistors are designed with longer extending lengths in the first extending direction to maximize sensitivity to force applied in that direction. The second and fourth sensing resistors have longer extending lengths in the second extending direction. This asymmetric design optimizes force detection sensitivity while the Wheatstone bridge configuration compensates for resistance value variations.
Solution Approach 2:
The Wheatstone bridge circuit acts as an intermediary that compensates for the increased resistance values of the longer sensing resistors. By balancing the resistance values in the bridge circuit and measuring voltage differences rather than absolute resistance changes, the system maintains accurate force measurement despite the longer resistor lengths that provide enhanced sensitivity.
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 temperature-related errors in force touch measurements, enhancing the accuracy of force detection and touch sensitivity while maintaining effective strain detection in different directions.
Implementation Method 1
at least one force sensing bridge including a first sensing resistor, a second sensing resistor, a third sensing resistor, and a fourth sensing resistor
Implementation Method 2
the first sensing resistor has a longer extending length in the first extending direction than in the second extending direction. From the first end to the second end of the second sensing resistor, the second sensing resistor has a longer extending length in the second extending direction than in the first extending direction
Data Source
AI summary
A touch control display panel and a touch control display device are provided. The touch control display panel comprises a substrate having a first extending direction and a second extending direction; and at least one force sensing bridge including a first sensing resistor, a second sensing resistor, a third sensing resistor, and a fourth sensing resistor. The first sensing resistor has a longer extending length in the first extending direction than in the second extending direction. The second sensing resistor has a longer extending length in the second extending direction than in the first extending direction. The third sensing resistor has a longer extending length in the first extending direction than in the second extending direction. The fourth sensing resistor has a longer extending length in the second extending direction than in the first extending direction.