Floating Lens Touch Screen with Pressure Sensors
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Solution Overview
Problem
Existing touch sensors for consumer electronics, such as computers and portable devices, face challenges in being both inexpensive and precise, requiring the ability to sense both fingers and pens over a wide pressure range with high positional accuracy and thin form factor, while also being modular for easy integration.
Innovation Solution
A touch screen assembly featuring a floating lens with differentially-mounted pressure sensors connected via a thin flex film, allowing for precise detection of touch coordinates and optional haptic feedback, enabling a thin and modular design suitable for various electronic devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If force sensors are used to measure touch location and magnitude, then measurement precision is improved, but device complexity increases due to multiple sensors and mathematical formulas required
Solution Approach 1:
The touch detection function is segmented into multiple pressure-sensitive transducers arranged in a matrix pattern beneath the lens assembly. Each transducer independently measures pressure at its location, and the controller processes these distributed measurements to determine touch position and force, replacing a single complex sensor system with multiple simpler units.
Solution Approach 2:
The patent replaces complex mechanical force sensor assemblies with pressure-sensitive transducers that convert mechanical pressure directly into electrical signals. This substitution simplifies the mechanical structure while maintaining the ability to measure both location and magnitude of applied force through electrical measurement rather than mechanical linkage.
2Measurement precision
If multiple pressure sensors are mounted beneath the lens assembly, then measurement precision is improved, but manufacturing complexity increases
Solution Approach 1:
Multiple pressure-sensitive transducers are merged into a single lens assembly unit that is pre-positioned beneath the lens. The transducers are arranged in a matrix pattern and electrically connected to a common controller, allowing them to be manufactured and tested as an integrated module before installation, thereby simplifying the overall manufacturing process despite the increased number of sensors.
3Measurement precision
If a floating lens design is used with pressure sensors, then measurement precision is improved, but device thickness increases
Solution Approach 1:
The lens assembly is designed as a thin, flexible structure that can float above the pressure-sensitive transducers with minimal clearance. This allows the floating lens design to achieve precise touch coordinate detection while maintaining a compact thickness suitable for portable electronic devices.
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 provides a low-cost, precise, and thin touch screen technology that can sense a wide range of pressures with high accuracy, suitable for integration into portable devices without disrupting their form factor, while also offering haptic feedback for enhanced user experience.
Implementation Method 1
a plurality (n=1...m) differentially-mounted pressure-sensitive transducers mounted beneath the lens assembly and electrically connected to measure a pressure z from a touch to the lens
Data Source
AI summary
A touch screen assembly for an electronic device such as a cell phone or PDA. The touch screen assembly generally comprises a floating lens suspended over the display and, optionally, the keypad to allow a degree of freedom. An underlying thin connecting layer such as a flex film is attached beneath the floating lens, and a plurality (for example, four) differentially-mounted pressure sensors are mounted beneath the floating lens and are electrically connected to the electronic device via the flex film. The pressure sensors are differentially positioned along an x- and y-axis for registering a pressure z from a touch to the lens at each of the four positions, to provide four data sets (x1-4, y1-4, z1-4). Control software then interprets the exact touch-coordinate from the four data sets and generates a control signal. An optional haptic response generator and/or motion sensor are also contemplated. When used in a smaller electronics device such as a cell phone or PDA the touch screen sensor technology of the present invention is exceedingly thin and is capable of modular assembly for more-or-less “snap-in” construction.