Vehicle Camera Hood Heating for Window Fog Detection
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Solution Overview
Problem
Existing on-board camera devices for vehicles struggle to efficiently detect and remove fog and dew condensation from the window glass while also monitoring the temperature state of both the window glass and the camera device, often requiring multiple temperature sensors which increase manufacturing costs.
Innovation Solution
The on-board camera device incorporates a camera unit, a hood member, a thermally conductive member, a heater device, and a single temperature measurement element. The thermally conductive member is in thermal contact with the window glass, and the heater device includes the temperature measurement element, allowing it to detect the window glass temperature during non-operation and the heater device temperature during operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single temperature measurement element is used to detect both window glass temperature and heater device temperature, then manufacturing cost is reduced and device complexity is simplified, but measurement precision may be compromised due to the dual-function requirement
Solution Approach 1:
The temperature measurement element is designed to perform dual functions: detecting window glass temperature during non-heating periods and detecting heater device temperature during heating periods. This multi-functionality eliminates the need for separate temperature sensors for each measurement task, reducing manufacturing cost and device complexity while maintaining adequate measurement precision for both purposes
Solution Approach 2:
The system dynamically switches the measurement target of the temperature measurement element based on operational state. During heater non-operation, the element measures window glass temperature; during heater operation, it measures heater device temperature. This dynamic adaptation allows a single sensor to accurately capture temperature information relevant to the current operational phase
2Reliability
If the heater device is operated continuously to prevent fogging, then defogging reliability is improved, but energy consumption increases and may cause unnecessary heating
Solution Approach 1:
The control unit continuously monitors temperature information from the temperature measurement element and adjusts heater operation accordingly. When the window glass temperature is below the dew point, the heater is activated to prevent fogging. When the temperature rises above the dew point, the heater is deactivated to save energy. This feedback-based control ensures the heater operates only when necessary, maintaining defogging reliability while minimizing energy consumption
Solution Approach 2:
The system proactively activates the heater when temperature conditions indicate a high risk of fogging (when window glass temperature approaches or falls below the dew point), preventing fog formation before it occurs. This preliminary action maintains clear visibility while avoiding continuous heating, as the heater is turned off once preventive heating has raised the temperature above the critical threshold
3Measurement precision
If temperature information is acquired from multiple locations to accurately detect fogging conditions, then measurement precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
A single temperature measurement element serves multiple measurement purposes by detecting both window glass temperature and heater device temperature depending on operational state. This eliminates the need for multiple dedicated temperature sensors while providing sufficient temperature information to accurately determine fogging conditions and control heater operation
Solution Approach 2:
The temperature measurement element leverages the existing thermal environment and operational states of the system to provide all necessary temperature measurements. During heater non-operation, it naturally measures window glass temperature; during heater operation, it measures heater device temperature. This self-service approach eliminates the need for additional dedicated measurement devices
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 configuration enables efficient defogging and reliable temperature monitoring of the window glass and camera device using a single temperature sensor, reducing manufacturing costs and improving the accuracy of fog detection and heater control.
Implementation Method 1
a thermally conductive member (14) which is made of a highly thermally conductive material and is fixed to an outer surface of the lens hood (12) to be in thermal contact with the window glass (100)
Implementation Method 2
The temperature measurement element is provided at a substantially center part of the heater device and includes a portion that is disposed in contact with the thermally conductive member. The temperature measurement element is configured to detect a temperature state of the heater device during operation of the heater device and detect a temperature state of the window glass transmitted through the thermally conductive member during non-operation of the heater device.
Data Source
AI summary
An on-board camera device includes a camera unit, a hood member, a thermally conductive member, a heater device, and a temperature measurement element. The camera unit captures an image of an ambient environment through a window glass of a vehicle. The hood member blocks an unnecessary light beam from outside and suppresses background reflection on the window glass. The thermally conductive member is fixed to the hood member to thermally contact with the window glass. The heater device contacts with the thermally conductive member and removes dew condensation and fog adhering to the window glass. The temperature measurement element is provided at the heater device and partly contacts with the thermally conductive member. The temperature measurement element detects a temperature state of the heater device during operation of the heater device and a temperature state of the window glass through the thermally conductive member during non-operation of the heater device.