Acoustic Touch Sensor Camera Hole Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Bezel-less acoustic touch sensors face issues with surface acoustic wave signal attenuation and touch sensitivity loss due to camera holes, which disrupt the propagation of surface acoustic waves and result in a dip in received signals and loss of touch sensitivity in certain areas.
Innovation Solution
A corrective acoustic lens is positioned adjacent to the camera hole on the substrate's border layer, made from acoustic material that adjusts the surface acoustic wave velocity to match the surrounding border layer, eliminating phase shifts and signal dips by canceling the perturbed wavefronts caused by the camera hole.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a camera hole is provided in the border layer to allow camera access, then optical functionality is enabled, but surface acoustic wave propagation is disrupted causing signal attenuation and touch sensitivity loss
Solution Approach 1:
An acoustic lens is introduced as an intermediary element positioned between the camera hole and the surface acoustic wave propagation path. The lens has a specific acoustic impedance matched to the border layer material, creating a gradual transition that reduces wavefront distortion and minimizes signal attenuation while preserving camera functionality
Solution Approach 2:
The acoustic lens modifies local acoustic parameters (impedance, wave velocity) in the region around the camera hole. By changing these parameters gradually rather than having a sharp discontinuity, the lens reduces the perturbation to surface acoustic waves and maintains touch sensitivity in the affected region
2Area of stationary object
If the active touch region is enlarged to maximize screen real estate, then device functionality is improved, but surface acoustic wave propagation is interfered with by additional features and functions
Solution Approach 1:
The border layer is designed with locally differentiated properties: regions with acoustic features have tailored acoustic impedances and wave velocities optimized for their specific functions, while other regions maintain uniform properties for consistent wave propagation. This local optimization allows larger active touch regions without compromising overall wave propagation reliability
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 corrective lens effectively eliminates signal dips and maintains touch sensitivity across the active touch region by compensating for the velocity changes caused by the camera hole, ensuring consistent surface acoustic wave propagation and accurate touch detection.
Implementation Method 1
a substrate capable of propagating surface acoustic waves
Implementation Method 2
A corrective acoustic lens is positioned adjacent to the camera hole on the substrate's border layer, made from acoustic material that adjusts the surface acoustic wave velocity to match the surrounding border layer
Data Source
Figure 1
Figure 2(a)~2(b)
Figure 3
AI summary
According to a specific embodiment, an acoustic touch apparatus comprising a substrate having a first surface and a second surface, the first and second surfaces capable of propagating surface acoustic waves, the second surface comprising a touch region and the first and second surfaces coupled via a rounded connecting surface; at least one acoustic wave transducer on the first surface; and at least one reflective array on the first surface, said transducer capable of transmitting or receiving surface acoustic waves to and from said reflective array, said substrate and said reflective array capable of acoustically coupling surface acoustic waves to propagate between the first and second surfaces, and said substrate having a border region on the first surface that is adapted to hide from view through the substrate the transducer and the reflective array and to preclude distortion of surface acoustic waves propagating over a window in the border region. In some embodiments, a border layer is on the border region except at the window and a corrective lens is used proximate the window. In other embodiments, the border region comprises discolored glass except at the window.