Optical Surface Cleaning Using Peripheral SAW and Lamb Wave Actuation
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Solution Overview
Problem
Existing methods for removing raindrops, ice, or snow from optical surfaces, such as windshields and sensors in vehicles, are inefficient and unsuitable for large areas, causing interference with the field of view and requiring frequent maintenance, especially for autonomous vehicles with numerous sensors.
Innovation Solution
A device featuring a piezoelectric layer and electrodes generating ultrasound surface waves or Lamb waves to efficiently clean optical surfaces by propagating these waves, allowing for effective removal of liquid or solid deposits without obstructing radiation transmission and minimizing interference with detection or emission equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a wiper is used to clean the optical surface, then the liquid body is removed from the surface, but the field of view is limited and greasy particles are spread
Solution Approach 1:
The patent replaces the mechanical wiper system with an acoustic field-based cleaning system. A transducer generates surface acoustic waves that propagate through the optical surface, creating vibrations that remove liquid bodies without mechanical contact. This eliminates the harmful effects of wipers while maintaining effective cleaning capability.
Solution Approach 2:
The invention utilizes mechanical vibration through surface acoustic waves generated by the transducer. The vibrations propagate through the optical surface and interact with liquid bodies, causing them to detach and be removed. This vibrational mechanism achieves cleaning without the mechanical contact and field of view limitations associated with wipers.
2Object-affected harmful factors
If electrodes are positioned precisely over the entire surface to control wetting properties, then the hydrophobic property is controlled, but the device complexity increases
Solution Approach 1:
The patent replaces the electrical field-based EWOD system with an acoustic field-based cleaning system. Instead of using electrodes to control wetting properties, the invention uses surface acoustic waves generated by a transducer to mechanically remove liquid bodies. This substitution significantly reduces device complexity while achieving the same cleaning objective.
3Area of stationary object
If a transducer is placed within the optical field, then the cleaning coverage is maximized, but shading effects on radiation transmission occur
Solution Approach 1:
The patent applies local quality by positioning the transducer at the periphery of the optical surface, specifically in a region where it does not obstruct the optical path. This allows the transducer to clean the entire optical surface through wave propagation while minimizing its impact on radiation transmission. The peripheral positioning creates a local arrangement that balances cleaning coverage with optical performance.
4Productivity
If the transducer extends over a large area of the optical surface, then the cleaning efficiency is improved, but the device becomes less compact and more difficult to integrate
Solution Approach 1:
The patent applies segmentation by confining the transducer to a specific peripheral region of the optical surface rather than distributing it across the entire area. The transducer is divided into discrete electrode fingers that generate surface acoustic waves, which then propagate across the full optical surface. This segmented approach allows compact transducer design while maintaining comprehensive cleaning coverage through wave propagation.
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 device enables efficient cleaning of optical surfaces by propagating ultrasound waves, ensuring clear radiation transmission and reducing maintenance needs, while being compact and suitable for large or curved surfaces, including those on autonomous vehicles.
Implementation Method 1
The wave transducer includes a piezoelectric layer and electrodes of opposite polarity in contact with the piezoelectric layer, and being configured to generate at least one ultrasound surface wave or Lamb wave propagating in the optical surface
Implementation Method 2
generate at least one ultrasound surface wave or Lamb wave propagating in the optical surface
Implementation Method 3
generate at least one ultrasound surface wave or Lamb wave propagating in the optical surface
Implementation Method 4
generate at least one ultrasound surface wave or Lamb wave propagating in the optical surface
Data Source
AI summary
The invention relates to a device (5) comprising: —an optical surface (10); —a cleaning unit (15) for cleaning the optical surface, comprising at least one wave transducer (70) acoustically coupled to the optical surface, the wave transducer having a piezoelectric layer (80) and electrodes (85) of opposite polarity in contact with the piezoelectric layer, and being configured to generate at least one surface ultrasonic wave (WS) or a Lamb wave (WL) propagating in the optical surface; —the optical surface having at least one region of optical interest (100) not superposed on the wave transducer, the device comprising an apparatus (20) configured to sense and/or to emit radiation (R) through the region of optical interest (100).