Vehicular Camera Imager PCB Mounting for Stable Focus
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Solution Overview
Problem
Existing vehicular vision systems face challenges in maintaining peak focus due to uneven mounting surfaces in camera housings, leading to deflection of the imager printed circuit board (imager PCB) and subsequent focus variation during the camera's life cycle.
Innovation Solution
The vehicular vision system incorporates an imager assembly with a lens barrel and an imager printed circuit board (imager PCB) that includes stress relieving portions and slots to absorb stresses and reduce flexing, thereby maintaining focus. Additionally, an attaching flange is used to secure the lens barrel, reducing stress on the imager PCB.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the imager PCB is directly attached to the camera housing, then the assembly process is simple, but the uneven mounting surface causes deflection and focus variation
Solution Approach 1:
A stress relieving portion is introduced as an intermediary element between the imager PCB and the camera housing. This stress relieving portion acts as a mediator that decouples the rigid connection, allowing the imager PCB to maintain its position and focus while the stress relieving portion absorbs the stress from the uneven mounting surface.
Solution Approach 2:
The connection structure is segmented into distinct functional zones: a rigid imager PCB portion for maintaining focus, a flexible stress relieving portion for absorbing stress, and an attaching portion for mounting. This segmentation allows each part to perform its specific function optimally without compromising the others.
2Strength
If rigid attachment is used to secure the imager PCB, then attachment strength is high, but stress from uneven surfaces causes focus variation
Solution Approach 1:
Different parts of the imager PCB assembly have different mechanical properties tailored to their specific functions. The imager PCB portion is rigid to maintain focus precision, while the stress relieving portion is flexible to absorb stress, and the attaching portion provides strong mechanical attachment. This local differentiation of mechanical properties resolves the contradiction between strength and precision.
3Manufacturing precision
If the imager PCB is made flexible to accommodate uneven surfaces, then focus stability improves, but attachment reliability decreases
Solution Approach 1:
The attachment system is divided into a flexible imager PCB portion for focus stability and a rigid attaching portion for reliable mechanical attachment. The flexible portion contains the stress relieving portion that bends to accommodate surface irregularities, while the rigid attaching portion maintains secure connection to the housing, thus resolving the contradiction between flexibility and reliability.
Data Source
AI summary
A vehicular camera module includes a housing for mounting at a vehicular windshield, a processor printed circuit board (processor PCB) disposed in the housing, and an imager assembly. The imager assembly includes (i) a lens barrel accommodating a lens, (ii) an imager printed circuit board (imager PCB), and (iii) a flexible electrical ribbon cable that electrically connects the imager PCB to the processor PCB. An imager is disposed at a first side of the imager PCB. The imager PCB includes an imager portion at which the imager is disposed and attaching portions at respective outboard ends. At least one stress relieving portion is established at the imager PCB between the imager portion and each of the attaching portions. With the lens barrel received through an aperture of the housing, the attaching portions of the imager PCB are attached at the housing via respective fasteners.