Vehicle Camera Assembly with CTE-Matched Lens Barrel and PCB
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Solution Overview
Problem
The deformation of lens barrels and PCBs due to differing coefficients of thermal expansion (CTE) during environmental testing at high temperatures affects the focus distance and optical performance of camera assemblies in vehicles.
Innovation Solution
A camera assembly design featuring a first lens barrel with integrally formed connecting portions and a second lens barrel with a smaller CTE, connected via screw threads, to compensate for thermal deformation, minimizing deformation impact on the PCB.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If AA adhesive is used to bond the lens barrel to the PCB after focusing, then the lens assembly is fixed in position, but the differing CTE between lens barrel and PCB causes deformation at high temperatures, affecting focus distance and optical performance
Solution Approach 1:
The patent changes the material parameter (CTE) of the lens barrel by selecting a material with a CTE matched to the PCB. This parameter change ensures that both components expand and contract at the same rate during temperature variations, preventing deformation and maintaining focus distance stability without requiring additional compensation mechanisms
Solution Approach 2:
The patent employs composite material selection where the lens barrel is made from a material specifically chosen for its thermal expansion characteristics. By using a material whose CTE matches the PCB, the assembly creates a thermally compatible composite structure that maintains dimensional stability across temperature ranges, resolving the contradiction between bonding strength and thermal deformation
2Ease of manufacture
If the lens barrel material has a different CTE than the PCB, then manufacturing and assembly are simplified, but thermal deformation occurs at elevated temperatures, changing focus distance and reducing optical performance
Solution Approach 1:
The patent modifies the material parameter (CTE) of the lens barrel to match the PCB's CTE. This parameter change eliminates thermal deformation during temperature cycling, ensuring that focus distance precision is maintained throughout the environmental testing process while keeping the assembly process simple and straightforward
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
Stabilizes the optical performance of camera assemblies by reducing focus distance variations and maintaining alignment under temperature changes, enhancing overall camera assembly stability.
Implementation Method 1
Due to the differing coefficients of thermal expansion (CTE) of the lens barrel and the PCB, the deformation of the lens barrel and the PCB varies at elevated temperatures
Data Source
AI summary
Embodiments of the present disclosure relates to a camera assembly and a vehicle using the camera assembly. The camera assembly includes a first lens barrel, a second lens barrel, at least one lens, and a circuit board. The first lens barrel having a first accommodating cavity. The second lens barrel is connected to the first lens barrel. The lens is held by the first lens barrel and positioned within the first accommodating cavity. The lens is configured to receive image light. The circuit board is adhered to an end of the second lens barrel away from the first lens barrel. An absolute value of a difference between a coefficient of thermal expansion (CTE) of the second barrel and that of the circuit board is less than an absolute value of a difference between a CTE of the first barrel and that of the circuit board.