Pressure Sensor Array with Half-Bridge Circuits for Touchscreen Detection
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Solution Overview
Problem
Conventional touchscreen pressure-sensitive solutions face challenges in achieving high sensitivity and precision due to interference, complex circuit designs, and increased costs, particularly in detecting pressure values in the Z-axis direction, which limits their ability to provide accurate and reliable touch input.
Innovation Solution
A pressure-sensitive detection apparatus featuring a pressure sensor array with half-bridge circuits, where each row includes multiple pressure sensors, and a switch circuit to activate only relevant half-bridge circuits corresponding to the touch location, amplifying the pressure-sensitive signal through differential amplification and reducing circuit energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a capacitive pressure-sensitive solution is used, then it can detect pressure values, but it is interfered with by a current capacitive touchscreen causing low resolution and requires a complex drive circuit increasing costs
Solution Approach 1:
The pressure sensor array is divided into multiple rows and columns, with each row containing multiple half-bridge circuits. This segmentation allows selective activation of only the relevant row and column circuits corresponding to the touch location, reducing the overall circuit complexity while maintaining pressure detection precision.
Solution Approach 2:
The patent introduces a row selection circuit and column selection circuit as intermediary components that act as mediators between the pressure sensor array and the control system. These intermediary circuits enable selective activation of specific half-bridge circuits, simplifying the drive circuit architecture while maintaining measurement precision.
2Measurement precision
If a piezoresistive or piezoelectric pressure-sensitive solution is used, then pressure values can be detected through impedance and voltage changes, but the detection unit deforms to an extremely small degree causing the electrical signal to be extremely small and likely drowned by noise
Solution Approach 1:
The patent employs a half-bridge circuit configuration where two pressure sensor units are arranged in opposition. When pressure is applied, one unit experiences increased resistance while the other experiences decreased resistance. This counterweight arrangement amplifies the differential signal, improving the signal-to-noise ratio and reliability of pressure detection.
Solution Approach 2:
The patent changes the measurement parameter from absolute resistance measurement to differential resistance measurement. By measuring the difference in resistance changes between two opposing pressure sensor units, the system amplifies the effective signal while rejecting common-mode noise, thereby improving reliability.
3Reliability
If structural mechanics is applied to amplify the electrical signal, then the signal-to-noise ratio is improved, but thickness is likely to be increased and the solution is likely to be affected by structural processing error making subsequent calibration troublesome
Solution Approach 1:
The patent replaces complex mechanical amplification structures with an electrical differential amplification approach using half-bridge circuits. This substitution eliminates the need for thick structural components and complex mechanical processing while achieving signal amplification through electrical means, thereby reducing device thickness and simplifying manufacturing.
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 enhances the sensitivity and precision of pressure-sensitive detection on touchscreens by effectively amplifying pressure signals and reducing circuit complexity and costs, allowing for accurate detection of touch input pressure values in the Z-axis direction.
Implementation Method 1
When a detection unit is pressed due to a force, impedance and a voltage of a sensor are changed
Implementation Method 2
the plate is deformed. Therefore, an inter-plate distance is changed, and then a capacitance of the detection capacitor is changed
Data Source
AI summary
The present disclosure relates to pressure-sensitive detection apparatus. One example apparatus includes a pressure sensor array located in a touch display screen. One half-bridge circuit is constituted in each row of the pressure sensor array. When there is a touch input signal on the touch display screen, a first half-bridge circuit and a second half-bridge circuit corresponding to a touch location of the touch input signal output signals. A deformation amount generated when pressure is applied to a first pressure sensor component in the first half-bridge circuit is less than a deformation amount generated when the pressure is applied to a second pressure sensor component in the first half-bridge circuit, and a deformation amount generated when the pressure is applied to a first pressure sensor component in the second half-bridge circuit is greater than a deformation amount generated when the pressure is applied to a second pressure sensor component in the second half-bridge circuit.