Image Pickup Unit Lens Alignment via Locking Portions
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Solution Overview
Problem
Existing image pickup units face challenges in accurately aligning the optical axis of the lens unit with the center of the light receiving portion of the image pickup chip, particularly in compact designs where space is limited, such as in endoscope applications.
Innovation Solution
The image pickup unit incorporates a transparent substrate with locking portions and a lens unit with corresponding locked portions, where the lens unit is aligned with the optical axis by fitting its locked faces onto the locking faces of the substrate, allowing for precise alignment of the optical axis with the image pickup chip, even in reduced dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the lens unit is designed to cover the entire image pickup chip with no space between them, then the alignment accuracy of the optical axis with the light receiving portion center is improved, but the device complexity and difficulty of assembly increase
Solution Approach 1:
The patent introduces a lens barrel as an intermediary component between the lens unit and the image pickup chip. The lens barrel includes a positioning structure with positioning protrusions that fit into positioning recesses on the image pickup chip, serving as a mediator to achieve precise alignment without requiring direct contact between the lens unit and chip edges.
Solution Approach 2:
The lens unit is divided into separate components: the lens element, the lens holder, and the lens barrel. This segmentation allows each component to be manufactured and positioned independently, with the lens barrel's positioning structure providing the alignment function, thereby simplifying the overall assembly process while maintaining high alignment accuracy.
2Volume of moving object
If the lens unit dimensions are reduced to be equal to or smaller than the image pickup chip, then the overall diameter of the image pickup unit is reduced, but the alignment precision becomes more difficult to maintain
Solution Approach 1:
The lens barrel acts as a mediator that provides precise positioning features (protrusions and recesses) even when the overall lens unit is compact. This intermediary structure ensures that alignment precision is maintained through mechanical interfitting rather than relying solely on the relative sizes of the lens unit and image pickup chip.
Solution Approach 2:
The positioning protrusions and recesses are pre-formed on the lens barrel and image pickup chip respectively, establishing the alignment relationship before final assembly. This preliminary positioning action ensures that even in a compact design, the optical axis is accurately aligned with the light receiving portion center from the outset.
Data Source
AI summary
An image pickup unit according to the embodiment includes an image pickup device chip having a rectangular shape in plan view, a transparent substrate which is equal in plan view dimensions to the image pickup device chip and is joined to the image pickup device chip, and a lens unit joined to the transparent substrate with the center of a light receiving portion of the image pickup chip aligned with the optical axis, in which, two locking portions are formed in the transparent substrate and two locked portions of the lens unit which is equal to or smaller than the image pickup device chip in plan view dimensions are fitted into or abut on the corresponding locking portions respectively.