Lens Unit Line-Contact Alignment Independent of Barrel Positioning
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Solution Overview
Problem
Existing lens alignment methods in lens units are inaccurate due to the reliance on the positioning accuracy of the holder in the lens barrel, which affects the alignment between adjacent lenses.
Innovation Solution
A lens unit design where adjacent lenses are aligned through line contact using annular contacting and contacted portions with a virtual perpendicular plane to the optical axis, and a lens barrel with fitting projections for radial positioning without direct contact, allowing for high-accuracy alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fifth lens is positioned in the radial direction via the holder, then the lens can be supported and positioned, but the accuracy of positioning the holder in the lens barrel affects the accuracy of alignment between the sixth lens and the fifth lens
Solution Approach 1:
The invention extracts the alignment function from the holder positioning system. By designing the contacting portion and contacted portion to directly contact each other with their contact line on the virtual perpendicular plane, the alignment between lenses is achieved independently of the holder's positioning accuracy in the lens barrel.
Solution Approach 2:
The contact line between the contacting portion and contacted portion acts as an intermediary mechanism that transfers and ensures accurate alignment between lenses. This contact line interface serves as a precise mediator that overrides the less accurate holder positioning system.
2Manufacturing precision
If lenses are aligned through direct contact between contacting portion and contacted portion, then alignment accuracy is improved, but the complexity of the lens structure increases
Solution Approach 1:
The invention applies local quality by creating specific contacting and contacted portions with precise geometric features (tapered surfaces, arcs) only where needed for alignment. The rest of the lens structure remains simple and conventional, thus achieving high alignment precision without overall structural complexity.
Solution Approach 2:
Instead of making the holder complex to achieve precise positioning, the invention inverts the approach by making the lens-contacting surfaces complex and precise while keeping the holder simple. The alignment precision is achieved through the inverted design of the contacting surfaces rather than through complex holder mechanisms.
Data Source
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AI summary
A lens unit (1) includes a first lens (L6) and a second lens (L5) arranged in this order from an image side (X2) toward an object side (X1). The second lens includes an annular contacting portion (26) in contact with the first lens on an outer peripheral side of a lens surface on the image side. The first lens includes an annular contacted portion (37) in contact with the contacting portion on an outer peripheral side of a lens surface on the object side. The contacting portion and the contacted portion are in line contact with each other. A contact line (M) along which the contacting portion and the contacted portion are in contact with each other has an annular shape coaxial with an optical axis (L) of the first lens and is located on a virtual perpendicular plane (S) perpendicular to the optical axis of the first lens.