SAW Touch Panel Signal Segmentation for Position Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Large-size surface acoustic wave (SAW) touch panels face challenges in accurately detecting touch positions due to signal attenuation over long propagation distances, leading to weak signals that are difficult to distinguish from noise.
Innovation Solution
The method involves generating multiple segments of SAW signals that are propagated and combined to form a complete output electrical signal, which is amplified to overcome signal weakness, and positions are detected by analyzing depressions in this signal, with adjustments made to partial output electrical signals to enhance detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the touch panel size is increased, then the coverage area is improved, but the signal attenuation increases making touch detection more difficult
Solution Approach 1:
The touch panel is divided into multiple detection regions with different gain settings. The signal processing is segmented into multiple gain stages, where different regions use different gain values to compensate for signal attenuation. This allows large-size panels to maintain detection reliability across the entire surface by treating different areas differently rather than using a uniform approach.
Solution Approach 2:
Different regions of the touch panel are assigned different gain characteristics based on their specific requirements. Regions farther from the transducer elements receive higher gain compensation. This local differentiation of signal processing parameters ensures that each region operates optimally despite variations in signal strength across the large panel surface.
2Measurement precision
If multiple SAW segments are propagated and combined, then the detection accuracy is improved, but the device complexity increases
Solution Approach 1:
The detection process is divided into multiple segments where separate SAW signals are propagated and processed independently. Each segment processes a portion of the touch panel surface, and the results are combined to form the complete detection picture. This segmentation approach improves accuracy by allowing focused processing of different regions while keeping individual processing tasks manageable.
Solution Approach 2:
Multiple processed SAW signal segments are merged together to form the complete touch position detection result. The individual segment results, each optimized for specific regions, are combined through coordinate transformation and data fusion to provide accurate touch position information across the entire panel, achieving high accuracy without requiring a single overly complex processing system.
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 approach allows for accurate detection of touch positions on larger SAW touch panels by maintaining signals within a predefined range and increasing the size of detectable depressions, thereby overcoming the limitations of signal attenuation.
Implementation Method 1
It converts an electrical signal to the SAW signal by using a transducer including a piezoelectric material
Implementation Method 2
These reflectors r are all partially transmissive and partially reflective
Data Source
AI summary
The present invention provides a method and device for position detection. For detection of a touch position, a segment of surface acoustic wave (SAW) is provided multiple times to be propagated on a SAW touch panel, and the multiple SAW segments are received by the SAW touch panel. In addition, during or after reception, partial output electrical signals are provided based on different portions of each received SAW segment to construct a complete output electrical signal.