Press Detecting Device With Temperature-Compensating Adhesives
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Solution Overview
Problem
Conventional touch input devices experience variations in detected pressing force due to temperature changes, as the Young's modulus of existing pressure-sensitive adhesives and fixing adhesives do not maintain consistent properties across temperature ranges, leading to inaccurate force detection.
Innovation Solution
A press detecting device is designed with a piezoelectric film, a holding member, an interlayer pressure-sensitive adhesive with high Young's modulus at low temperatures and low Young's modulus at high temperatures, and a fixing adhesive with the opposite temperature-dependent properties, which suppresses distortion and electric charge changes, ensuring stable pressing force detection across temperature variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a pressure-sensitive adhesive layer with translucency is used between the pressure sensitive sensor and the touch panel, then the device maintains optical transparency, but the detected pressing force varies with temperature changes
Solution Approach 1:
The patent applies parameter changes by selecting adhesive materials with specific temperature-dependent Young's modulus characteristics. The interlayer pressure-sensitive adhesive has a large Young's modulus at low temperatures and a small Young's modulus at high temperatures, while the fixing adhesive has the opposite characteristic. This parameter variation with temperature compensates for distortion effects, maintaining consistent pressing force detection across temperature ranges while preserving translucency.
Solution Approach 2:
The patent uses composite materials by combining two different pressure-sensitive adhesives with complementary temperature-dependent properties. The interlayer pressure-sensitive adhesive and the fixing adhesive form a composite adhesive system where their opposing Young's modulus temperature characteristics work together to cancel out temperature-induced distortion effects on the pressure sensitive sensor.
2Adaptability or versatility
If the Young's modulus of the adhesive changes with temperature, then the adhesive remains flexible across temperature ranges, but distortion transmission to the pressure sensitive sensor varies, causing detection errors
Solution Approach 1:
The patent applies preliminary anti-action by pre-designing the adhesive system with opposing Young's modulus temperature characteristics. The interlayer pressure-sensitive adhesive's large Young's modulus at low temperatures prevents excessive distortion transmission when cold, while the fixing adhesive's large Young's modulus at low temperatures restrains the holding member. At high temperatures, the roles reverse, creating a compensatory effect that preliminarily counteracts temperature-induced detection errors before they occur.
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 stabilizes the detection of pressing force by minimizing the impact of temperature changes on the output voltage, allowing for accurate and consistent force measurement without temperature influence.
Implementation Method 1
a press sensor having a piezoelectric film
Data Source
AI summary
A touch input device that includes a housing; a touch detecting sensor having a piezoelectric film; a holding member; an interlayer pressure-sensitive adhesive that fixes the touch detecting sensor to the holding member; and a fixing adhesive that fixes the holding member to the housing. The interlayer pressure-sensitive adhesive has a large Young's modulus at lower temperatures and a small Young's modulus at higher temperatures. The fixing adhesive has a large Young's modulus at lower temperatures and a small Young's modulus at higher temperatures.