Capacitive Moisture Sensor for Surveillance Camera Lens
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Solution Overview
Problem
Surveillance cameras, especially those outdoors, face challenges in maintaining clear lenses due to environmental elements like rain, ice, and dirt, which affect image quality and require effective moisture detection and removal systems.
Innovation Solution
A capacitive moisture sensor system is integrated into surveillance cameras, featuring a transparent substrate with conductive electrodes and electrical contacts, connected to a controller that uses capacitive sensing to differentiate between moisture, ice, and debris, activating a wiper, defroster, or washer as needed to maintain lens clarity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a capacitive moisture sensor is integrated into the surveillance camera, then moisture detection capability is improved, but device complexity increases
Solution Approach 1:
The capacitive moisture sensor is integrated directly into the camera housing structure, merging the sensing function with the existing camera body. The substrate is positioned adjacent to the lens, and the electrodes are formed on the substrate, combining multiple components into a unified structure that detects moisture without requiring separate external sensing devices.
Solution Approach 2:
The substrate serves multiple functions: it acts as the mounting structure for the capacitive sensor electrodes, provides structural support for the sensor assembly, and is positioned to facilitate both moisture detection and optical function. This multi-functionality reduces the need for additional separate components.
2Illumination intensity
If transparent conductive material is used for electrodes, then optical transparency is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent specifies using transparent conductive materials with particular electrical and optical properties. The conductive material is applied in controlled thicknesses and patterns to achieve the desired balance between electrical conductivity for capacitive sensing and optical transparency for camera function. This parameter optimization allows the electrodes to perform both electrical and optical functions effectively.
3Measurement precision
If the substrate is positioned adjacent to the lens, then moisture detection effectiveness is improved, but risk of moisture ingress increases
Solution Approach 1:
The substrate acts as an intermediary element positioned between the external environment and the camera internal components. It is configured to detect moisture on its outer surface while the camera housing and sealing structures prevent moisture from penetrating inward. The substrate's strategic positioning allows it to serve as both the sensing surface and a protective barrier.
Solution Approach 2:
The capacitive sensor system automatically detects moisture conditions and can trigger responsive actions such as activating heating elements or wipers to clear the substrate surface. This self-monitoring and self-responsive capability maintains detection effectiveness while protecting the system from moisture-related damage.
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 system effectively detects and responds to various environmental conditions, ensuring continuous lens clarity by automatically cleaning or defrosting the lens, thereby maintaining optimal image quality and camera functionality.
Implementation Method 1
capacitive sensor that senses capacitance of the substrate
Implementation Method 2
capacitive sensing to differentiate between moisture, ice, and debris
Data Source
AI summary
An inter-digital capacitive sensor and control system are used to distinguish between rain, ice, dirt and debris on the outer lens surface of a surveillance camera. The electrodes of the capacitive sensor are made from a conductive coating such as printed epoxy or a transparent conductive oxide, that is directly deposited onto the inner surface of the lens. A defroster is spaced radially-outward from the capacitive sensor and is formed by metal deposition directly on the substrate surface.