Pyroelectric Touch Panel Noise Cancellation
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Solution Overview
Problem
Touch panels using pyroelectric materials are affected by pyroelectric noise due to temperature changes, leading to malfunction.
Innovation Solution
The touch panel design incorporates a configuration where the first and second pyroelectric materials generate polar charges that are partially offset at different temperature changes, reducing the electric potential difference between their electrodes and thereby suppressing pyroelectric noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pyroelectric material is used in the touch panel to detect press pressure, then the sensitivity of detecting press pressure is improved, but pyroelectric noise is generated when the temperature changes, causing the touch panel to malfunction
Solution Approach 1:
The pyroelectric material is divided into a first pyroelectric material and a second pyroelectric material with different polarizations. Each material generates pyroelectric charge in response to temperature changes, but with opposite polarities. By segmenting the single pyroelectric material into multiple materials with different polarization directions, the patent achieves cancellation of temperature-induced noise while preserving press pressure detection capability.
Solution Approach 2:
The first and second pyroelectric materials are polarized in opposite directions, creating counteracting pyroelectric charges. When temperature changes occur, the pyroelectric charges generated by the two materials oppose each other, effectively canceling out the temperature-induced noise. This counterweight approach allows the system to maintain sensitivity to press pressure while being insensitive to temperature variations.
2Object-affected harmful factors
If the first and second pyroelectric materials are polarized in opposite directions to cancel temperature-induced noise, then pyroelectric noise is suppressed, but the device structure becomes more complex
Solution Approach 1:
The first and second pyroelectric materials are combined in a layered structure where they are stacked alternately with conductive layers in between. This merging approach integrates the noise-cancellation function into the existing touch panel structure, allowing both materials to work together as a unified system rather than separate components, thereby reducing overall structural complexity.
Solution Approach 2:
The first and second pyroelectric materials serve multiple functions simultaneously: they detect press pressure through their piezoelectric effect and cancel temperature-induced noise through their pyroelectric effect with opposite polarizations. This multi-functionality reduces the need for separate components, simplifying the overall device structure while achieving noise suppression.
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 effectively minimizes the impact of pyroelectric noise from temperature changes, allowing the touch panel to accurately detect press pressure without interference.
Implementation Method 1
When the pyroelectric material undergoes a temperature change, a voltage is generated by the pyroelectric effect, causing noise output (pyroelectric noise).
Implementation Method 2
When the piezoelectric material is pressed, the piezoelectric material generates a voltage corresponding to the change in strain with time during pressing.
Data Source
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AI summary
An object of the present invention is to provide a touch panel that is hardly affected by pyroelectric noise due to temperature changes. As a means for achieving the above object, the present invention provides a touch panel 2. The touch panel 2 comprises a first pyroelectric material 26 and a second pyroelectric material 27, and is capable of detecting press pressure applied to the first pyroelectric material 26 and/or the second pyroelectric material 27. The upper surface of the first pyroelectric material 26 and the lower surface of the second pyroelectric material 27 are surfaces on which a positive charge is generated when the temperature increases, and a negative charge is generated when the temperature decreases. The lower surface of the first pyroelectric material 26 and the upper surface of the second pyroelectric material 27 are surfaces on which a negative charge is generated when the temperature increases, and a positive charge is generated when the temperature decreases. An electrode disposed on the first surface of the first pyroelectric material 26 and an electrode disposed on the first surface of the second pyroelectric material 27 are electrically connected to each other, and an electrode disposed on the second surface of the first pyroelectric material 26 and an electrode disposed on the second surface of the second pyroelectric material 27 are electrically connected to each other.