Symmetrical Pressure Sensor Output Amplification
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Solution Overview
Problem
In touch input devices, particularly in mobile terminals, the narrow peripheral edge of the display device poses challenges for pressure detection unit placement, leading to image distortion and inadequate sensitivity due to overlapping with the display device, and insufficient output from pressure sensitive sensors when placed between the display module and the base plate.
Innovation Solution
A pressure detection device with a pair of pressure sensitive portions symmetrically located on a pressure sensitive sensor, which includes a first and second insulating layer, an elastic member, and drive and sense electrodes, configured to amplify output by adding sign-reversed pressure changes, and an information input apparatus with a support structure that allows initial load setting before assembly, enhancing sensitivity and facilitating manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the pressure detection unit is provided at the center of the display device in a state overlapped with the display unit, then the pressure detection unit can be disposed on the display device, but a pressure is applied to a part of the display device from the pressure detection unit, resulting in a distortion in the image, which is referred to as pooling
Solution Approach 1:
The pressure detection unit is extracted from the display device structure and disposed on the base plate rather than being overlapped with the display device. This separation eliminates the harmful effect of image distortion while maintaining pressure detection functionality.
Solution Approach 2:
The pressure detection unit is moved from a vertical overlap position (center of display device) to a horizontal position on the base plate. This dimensional change in placement strategy resolves the contradiction by positioning the pressure detection unit in a different spatial plane that does not interfere with the display device.
2Object-affected harmful factors
If the pressure detection unit is provided between a peripheral edge portion of the display module and the base plate, then the pressure detection unit can be disposed without overlapping the display device, but the peripheral edge of the display device has a narrow width, making it difficult to dispose a pressure detection unit on the edge portion
Solution Approach 1:
The pressure detection unit is positioned on the base plate in a horizontal plane rather than being constrained to the vertical edge portion of the display device. This dimensional change in placement strategy provides sufficient space for the pressure detection unit while avoiding overlap with the display device.
3Object-affected harmful factors
If the pressure detection unit is provided corresponding to the entirety of the display device, then the pressure detection unit can be disposed without overlapping the display device, but the output of the pressure sensitive sensor becomes insufficient depending on the configuration of the information input device, which leads to inadequate sensitivity
Solution Approach 1:
The pressure detection unit is configured with a specific structural design that enhances local pressure detection capability. The pressure sensitive sensor is positioned and structured to provide sufficient output signal while the pressure detection unit is disposed on the base plate to avoid image distortion.
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
The solution enhances the sensitivity of pressure sensitive sensors by amplifying output and allows for initial load setting before assembly, addressing the challenges of image distortion and inadequate sensitivity in touch input devices.
Implementation Method 1
The sensor member is configured to change in resistance in a case that a pressing force applied to the pressure sensitive sensor changes
Implementation Method 2
an elastic member disposed at a position to which a pressing force is applied
Data Source
AI summary
A pressure detection device includes a pressure sensitive sensor and a pressure calculating unit. The pressure sensitive sensor includes an upper base substrate, a lower base substrate, and a pressure sensitive layer formed on a surface of one of the base substrates. The pressure sensitive layer includes a pair of pressure sensitive portions located symmetrically with respect to a plane center. A first elastic body and a second elastic body are disposed at a position to which a pressing force is applied. A first electrode and a second electrode are disposed with the pressure sensitive layer. The pressure calculating unit is configured to cause the pressure sensitive sensor to detect a pressure change for each of the pair of pressure sensitive portions and to add a sign-reversed pressure change in a pressure sensitive portion to a pressure change in the other pressure sensitive portion to amplify an output.