Vehicle Camera Single Point PCB Fixation Thermal Stress
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Solution Overview
Problem
Conventional vehicle vision systems face mechanical stress and focus drift due to differential thermal expansion of materials, particularly when multiple fixation points are used for attaching the printed circuit board (PCB) to the lens holder, leading to misalignment and reduced focus stability over temperature ranges.
Innovation Solution
A camera assembly with a single point fixation of the PCB to the lens holder, utilizing a post or protrusion and a non-circular aperture, which reduces mechanical stress and maintains alignment through adhesive bonding, and optionally includes a damper for vibration control, allowing for UV or heat curing of the adhesive without side space requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If multiple fixation points are used to attach the PCB to the lens holder, then the mechanical strength and attachment reliability are improved, but differential thermal expansion causes mechanical stress and focus drift, worsening alignment precision and focus stability
Solution Approach 1:
The patent extracts the problematic multiple fixation points and replaces them with a single fixation point located at the optical axis. This eliminates the differential thermal expansion stress between multiple attachment points while maintaining sufficient mechanical strength through the strategically positioned single point, thereby resolving the contradiction between attachment strength and alignment precision
Solution Approach 2:
The patent employs asymmetric positioning of the single fixation point at the optical axis rather than symmetric distribution of multiple points. This asymmetric placement optimizes the mechanical stress distribution and minimizes thermal expansion-induced misalignment, achieving both strong attachment and precise alignment
2Stability of the object's composition
If multiple fixation points are used to attach the PCB to the lens holder, then the mechanical stability is improved, but the complexity of the attachment structure and adhesive application increases
Solution Approach 1:
The patent simplifies the attachment structure by extracting unnecessary fixation points and retaining only one critical fixation point at the optical axis. This reduction from multiple points to a single point maintains mechanical stability while significantly reducing the complexity of the attachment structure and adhesive application process
Solution Approach 2:
The single fixation point serves multiple functions simultaneously: it provides mechanical support, ensures optical alignment, and simplifies the attachment structure. This multi-functionality resolves the contradiction by achieving mechanical stability without the complexity of multiple fixation points
3Manufacturing precision
If a single point fixation is used to attach the PCB to the lens holder, then the focus stability over temperature range is improved, but the mechanical stress concentration increases
Solution Approach 1:
The patent positions the single fixation point asymmetrically at the optical axis, which is the optimal location for minimizing thermal expansion-induced stress concentration. This strategic positioning maintains focus stability across temperature ranges while distributing stress more effectively than arbitrary single-point locations
Solution Approach 2:
The single fixation point acts as an intermediary that connects the PCB and lens holder while accommodating thermal expansion differences. By positioning it at the optical axis, it mediates the thermal stress in a way that preserves focus stability without excessive stress concentration
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 enhances focus stability over a wide temperature range, reduces production cycle time, and allows for a more compact camera design with less adhesive usage, while maintaining precise alignment of the imager with the lens.
Implementation Method 1
the protrusion and structure are adhesively bonded together to secure the PCB relative to the lens holder and thus to secure the imager relative to and aligned with the lens
Implementation Method 2
optionally includes a damper for vibration control
Implementation Method 3
allowing for UV or heat curing of the adhesive
Implementation Method 4
allowing for UV or heat curing of the adhesive
Data Source
AI summary
A method of assembling a camera for a vehicular vision system includes providing a front housing portion, a rear housing portion and a circuit element having an imager disposed thereat. One of the front housing portion and the circuit element includes a protrusion protruding therefrom and the other of the front housing portion and the circuit element includes a receiving portion for at least partially receiving the protrusion when the circuit element is positioned at the front housing portion to align the imager with the lens. When the circuit element is positioned at the front housing portion to align the imager with the lens, the protrusion is at least partially received at the receiving portion and is attached thereat. A damper or retention feature is provided at an opposite side of the imager from the protrusion and receiving portion.