Touch Sensing Using Acoustic and Optical Signals
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Solution Overview
Problem
Conventional optical touch apparatuses are large, costly, and consume high energy due to the need for multiple light-emitting and light-sensing devices, which limits their size reduction and energy efficiency.
Innovation Solution
A touch-sensing apparatus using a combination of a mechanical wave-receiving unit and an electromagnetic wave-receiving unit, where the touch object emits both signals, allowing the control unit to determine the position based on the time difference and azimuth angle, reducing the need for multiple devices and enabling energy-saving operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple light-emitting and light-sensing devices are used in conventional optical touch apparatuses, then touch detection function is achieved, but device size and energy consumption increase
Solution Approach 1:
The patent combines multiple sensing functions into a single sensor that can detect both acoustic waves (from finger touches) and optical signals (from display pixels). This merging eliminates the need for separate light-emitting and light-sensing devices, thereby reducing energy consumption while maintaining touch detection functionality.
Solution Approach 2:
The sensor is designed with multi-functionality to serve multiple purposes: detecting acoustic waves from touches, sensing optical signals from the display, and potentially other environmental signals. This universal approach replaces multiple specialized devices, reducing overall system energy consumption and component count.
2Reliability
If multiple light-emitting and light-sensing devices are used in conventional optical touch apparatuses, then touch detection function is achieved, but device size increases
Solution Approach 1:
The patent combines multiple sensing functions into a single sensor that can detect both acoustic waves (from finger touches) and optical signals (from display pixels). This merging eliminates the need for separate light-emitting and light-sensing devices, thereby reducing device size while maintaining touch detection functionality.
Solution Approach 2:
The sensor is designed with multi-functionality to serve multiple purposes: detecting acoustic waves from touches, sensing optical signals from the display, and potentially other environmental signals. This universal approach replaces multiple specialized devices, reducing overall system size and footprint.
3Measurement precision
If light-emitting devices and light-sensing devices are disposed in pairs at corners of touch region, then touch position calculation is enabled, but device complexity and installation cost increase
Solution Approach 1:
The patent extracts and removes the complex light-emitting device components from the system. Instead of using active light emission, the system passively detects optical signals already present from the display pixels, thereby simplifying the device structure and reducing installation complexity while maintaining position detection capability.
Solution Approach 2:
The patent replaces the mechanical/optical emission system with an acoustic wave detection system. By detecting acoustic waves generated during touches and combining them with optical signal timing, the system achieves position calculation without requiring complex light-emitting hardware arrangements.
4Speed
If light-emitting devices and light-sensing devices operate continuously, then touch detection responsiveness is maintained, but energy consumption increases
Solution Approach 1:
The patent implements periodic sampling of optical signals from display pixels rather than continuous monitoring. The sensor detects acoustic waves continuously but samples optical information at specific intervals synchronized with display refresh rates, maintaining detection responsiveness while significantly reducing energy consumption compared to continuous operation.
Solution Approach 2:
The system utilizes signals that are already present in the environment (acoustic waves from touches and optical signals from display pixels) rather than requiring active emission. The display pixels themselves serve as the light source, and the acoustic waves provide the touch indication, eliminating the need for separate active light-emitting devices that would consume continuous energy.
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 results in a smaller, more energy-efficient touch system that can be integrated into various display apparatuses without the need for additional components, providing accurate touch detection with reduced energy consumption.
Implementation Method 1
The mechanical wave-receiving unit is configured to receive a mechanical wave signal actively emitted by a touch object
Implementation Method 2
The electromagnetic wave-receiving unit is configured to receive an electromagnetic wave signal actively emitted by the touch object
Implementation Method 3
the control unit is configured to decide an azimuth angle of the touch object on the sensing surface with respect to the signal-receiving module according to the electromagnetic wave signal received by the electromagnetic wave-receiving unit
Implementation Method 4
the control unit is configured to decide a distance of the touch object on the sensing surface with respect to the signal-receiving module according to a time difference of the mechanical wave signal received by the mechanical wave-receiving unit and the electromagnetic wave signal received by the electromagnetic wave-receiving unit
Data Source
AI summary
A touch-sensing apparatus includes a signal-receiving module and a control unit. The signal-receiving module includes a mechanical wave-receiving unit and an electromagnetic wave-receiving unit. The mechanical wave-receiving unit is configured to receive a mechanical wave signal actively emitted by a touch object. The electromagnetic wave-receiving unit, adjacent to the mechanical wave-receiving unit, is configured to receive an electromagnetic wave signal actively emitted by the touch object. The control unit is electrically connected to the mechanical wave-receiving unit and the electromagnetic wave-receiving unit, and decides an azimuth angle and a distance of the touch object on a sensing surface with respect to the signal-receiving module according to the electromagnetic wave signal and the mechanical wave signal, and decides a position of the touch object on the sensing surface according to the azimuth angle and the distance. A touch system and a touch-detection method are also provided.