Vehicle Camera Device Holder Thermal Expansion Design
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Solution Overview
Problem
Vehicle-mounted cameras with fixed focal length configurations face challenges in maintaining superior performance across a wide range of environmental temperatures, as changes in temperature lead to shifts in the focal length of the optical system and the dimensions of the camera housing, potentially causing the electrical connection between the imaging device and the substrate to break.
Innovation Solution
The optical apparatus incorporates a device holder with multiple materials of different thermal characteristics, where the linear expansion coefficient of one material is greater than that of another, allowing the device holder to deform and maintain the imaging device's position near the focal plane, thus reducing stress on the electrical connection and preventing breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a fixed focal length configuration lens is used to reduce cost and compactness, then the apparatus becomes more compact and cost-effective, but the camera cannot maintain superior performance across a wide environmental temperature range due to thermal expansion and focal length changes
Solution Approach 1:
The device holder is constructed from multiple materials with different linear expansion coefficients (first material with higher expansion coefficient, second material with lower expansion coefficient) arranged in the optical path direction. This differential thermal expansion creates controlled deformation of the device holder that compensates for thermal displacement of the image focal plane, maintaining imaging performance across temperature changes without requiring active focus adjustment mechanisms.
Solution Approach 2:
The device holder employs a composite structure combining at least two different materials (first member with first material, second member with second material) that have different thermal properties. This composite construction allows the holder to exhibit controlled thermal deformation characteristics that counteract the thermal expansion of the housing and optical system, thereby maintaining the imaging device at the correct focal position across a wide temperature range.
2Temperature
If the housing dimensions increase due to thermal expansion at higher temperatures, then the distance between the optical system and imaging device increases, but this causes the imaging device to move away from the in-focus position, degrading performance
Solution Approach 1:
The differential thermal expansion between the first and second materials in the device holder creates a compensating deformation mechanism. When temperature increases cause the housing to expand and push the imaging device away from focus, the device holder deforms in a controlled manner (with the first material expanding more than the second material) to counteract this displacement and maintain the imaging device at the correct focal position.
3Adaptability or versatility
If the focal length becomes shorter due to increased lens intervals and refractive index changes at higher temperatures, then the in-focus position shifts, but maintaining fixed focal length configuration limits the ability to compensate for these changes
Solution Approach 1:
The device holder utilizes differential thermal expansion of its composite materials to physically adjust the position of the imaging device in response to temperature-induced focal length changes. As temperature increases cause the optical system's focal length to shorten and the in-focus position to shift, the device holder deforms to move the imaging device accordingly, maintaining proper focus without requiring active focal length adjustment mechanisms.
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 ensures that the vehicle-mounted camera maintains excellent performance across a wide range of environmental temperatures by minimizing the impact of thermal expansion on the electrical connection and maintaining the imaging device's optimal position relative to the optical system.
Implementation Method 1
the device holder includes, in order of proximity to the lens in an optical path direction along an optical axis of the lens, a first member containing a first material, and a second member containing a second material different from the first material, and wherein a linear expansion coefficient of the first material is larger than a linear expansion coefficient of the second material
Data Source
AI summary
An optical apparatus includes a lens, a lens holding member configured to hold the lens, an imaging device configured to receive light that has passed through the lens at an imaging plane of the imaging device to convert the received light into an electrical signal, and a device holder configured to hold the imaging device, the lens, the lens holding member, the imaging device, and the device holder being integrally formed in the optical apparatus, wherein the device holder holds a surface of the imaging device, the surface being different from the imaging plane and a surface opposite to the imaging plane, wherein the device holder includes, in order from the lens in an optical path direction, a first member containing a first material, and a second member containing a second material, and wherein a linear expansion coefficient of the first material is larger than that of the second material.