Ultrasonic Touch Screen Transducer Electrode Length Variation
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Solution Overview
Problem
Conventional touch screens face challenges such as reduced screen brightness and sensitivity due to resistive films, limited functionality with wet fingers or nonconductive materials, and increased complexity and cost with larger display panels, making them difficult to apply effectively.
Innovation Solution
A display apparatus utilizing a touch screen with transducers spaced apart at the edges to transmit and receive ultrasonic signals, where electrodes are arranged alternately with different polarities and lengths to identify touch positions based on signal reflection times, allowing for accurate touch detection without the need for extensive sensor arrays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If resistive films are stacked on a display panel to create a touch screen, then touch detection functionality is achieved, but screen brightness is lowered and process detection sensitivity is decreased
Solution Approach 1:
The patent replaces the resistive mechanical touch detection system with an ultrasonic wave-based detection system. Instead of using resistive films that physically detect touch through pressure, the system uses ultrasonic transducers that emit and receive ultrasonic waves to detect touch positions, thereby eliminating the need for resistive films and maintaining screen brightness while achieving touch detection functionality
2Measurement precision
If the number of sensors is increased to cover larger display panels, then touch detection accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The patent divides the large display panel into multiple zones, each covered by a single ultrasonic transducer. By strategically positioning multiple transducers across the panel and using time-difference of arrival (TDOTA) calculations, the system achieves accurate touch detection across the entire large display area without requiring a dense array of sensors, thus reducing system complexity while maintaining precision
3Area of stationary object
If conventional touch screens are designed for larger display panels, then coverage area is increased, but sensitivity and responsiveness may be compromised
Solution Approach 1:
The patent utilizes ultrasonic vibration waves to detect touch inputs on large display panels. The ultrasonic transducers emit high-frequency mechanical vibrations that travel through the display panel, and when a user touches the panel, the vibrations are reflected or absorbed. This mechanical vibration-based detection maintains high sensitivity and responsiveness across large display areas, as the ultrasonic waves can effectively penetrate and interact with touch inputs regardless of panel size
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 enables accurate and efficient touch position detection on larger display panels with a simple structure, improving sensitivity and usability while reducing costs and complexity.
Implementation Method 1
a plurality of transducers provided to be spaced apart from each other at edges of the touch screen, and configured to transmit and receive an ultrasonic signal with respect to the touch screen
Implementation Method 2
the processor configured to obtain a distance between the transducer and the touch position based on time from a point in time of transmitting the ultrasonic signal to a point in time of receiving the ultrasonic signal reflected by the touch position
Data Source
AI summary
The display apparatus includes a display including a touch screen; a plurality of transducers provided to be spaced apart from each other at edges of the touch screen, and configured to transmit and receive an ultrasonic signal with respect to the touch screen; and a processor configured to identify a touch position on the touch screen based on the ultrasonic signal transmitted and received by the plurality of transducers, wherein the transducer includes a plurality of electrodes arranged from an edge side of the touch screen toward an inner side of the touch screen, and a first electrode at the edge side among the plurality of electrodes is shorter than a second electrode at the inner side.