Ultrasonic Waveguide Touch Panel for Large Displays
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Solution Overview
Problem
Large-sized display devices face challenges in implementing resistive and capacitive touch screen panels due to difficulties in forming fine electrode patterns and increased manufacturing costs for multi-touch detection, as existing technologies struggle to efficiently sense multiple touches without increasing sensor numbers.
Innovation Solution
A touch screen panel utilizing a wave guide with transmitters and receivers that output and receive ultrasonic or light waves, detecting touch positions based on time differences and wave speeds to sense multiple touches with a reduced number of sensors, thereby lowering manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If resistive or capacitive touch screen panels are applied to very large-sized display devices, then touch sensing function is provided, but it becomes difficult to form fine electrode patterns and manufacturing complexity increases
Solution Approach 1:
The patent replaces the electrical field-based sensing mechanism (electrodes) with an acoustic wave-based sensing mechanism. Instead of using conductive film electrodes that require fine patterning, the invention uses ultrasonic waves propagating through a waveguide to detect touch positions, thereby eliminating the manufacturing difficulties associated with forming fine electrode patterns on large areas.
Solution Approach 2:
The patent introduces a waveguide as an intermediary medium that carries ultrasonic waves across the touch surface. The waveguide serves as a platform that enables acoustic wave propagation and touch detection without requiring direct electrode patterns on the large display area, thus simplifying the manufacturing process for large-sized devices.
2Adaptability or versatility
If infrared or ultrasonic wave sensors are used to detect multi-touches, then the number of sensors must be increased, but manufacturing cost increases
Solution Approach 1:
The patent makes a single waveguide perform multiple functions: it serves as both the propagation medium for ultrasonic waves and the sensing element for detecting multiple touch positions. By using one waveguide with ultrasonic wave propagation, the system can detect multiple simultaneous touches without requiring multiple separate sensors, thereby reducing the quantity of sensing components while maintaining multi-touch capability.
Solution Approach 2:
The patent transitions from a two-dimensional sensor array approach to a one-dimensional wave propagation approach. Instead of placing sensors across the entire two-dimensional surface area, the invention uses ultrasonic waves traveling along a one-dimensional waveguide path to detect touch positions, reducing the number of sensing elements required while maintaining the ability to detect multiple touches.
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
Enables the detection of multiple touches with a reduced number of sensors, making it cost-effective and suitable for large-sized display devices while maintaining accuracy in touch position and pressure detection.
Implementation Method 1
the first receiver and the second receiver may receive the one of the ultrasonic wave and the light wave totally reflected and transferred through the wave guide
Implementation Method 2
the wave guide may include a material having a refractive index which is different from a refractive index of external air
Data Source
AI summary
A touch screen panel includes: a wave guide; a first transmitter at a first end of the wave guide to output an ultrasonic or light wave into the wave guide; a second transmitter at a second end of the wave guide to output the ultrasonic or light wave into the wave guide; a first receiver at the first end to receive the ultrasonic or light wave from the second transmitter and generate a first receipt signal; a second receiver at the second end to receive the ultrasonic or light wave and generate a second receipt signal; and a controller connected to the first receiver and the second receiver to detect a touch position on the wave guide using a time difference between a time point at which the first receipt signal is varied and a time point at which the second receipt signal is varied.