Plastic Lens Outer Ring Design for Coaxiality and Flatness
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Solution Overview
Problem
Conventional injection molded plastic lens elements often suffer from insufficient flatness and coaxiality issues, leading to manufacturing challenges and reduced image quality in optical systems.
Innovation Solution
The imaging lens system incorporates a plastic lens element design featuring an optical effective portion surrounded by an outer ring portion with annular grooves, conical surfaces, flat abutting portions, and full-circle connecting portions, which are tapered and strategically positioned to improve flatness, coaxiality, and assembly accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional injection molded plastic lens elements are used, then manufacturing cost is reduced and shape design flexibility is increased, but manufacturing precision deteriorates due to insufficient flatness and coaxiality
Solution Approach 1:
The plastic lens element is divided into two functional zones: an optical effective portion for light transmission and an outer ring portion for structural support and positioning. This segmentation allows the optical portion to be optimized for imaging while the outer ring is optimized for mechanical precision, flatness, and coaxiality, thereby resolving the contradiction between ease of manufacture and manufacturing precision.
Solution Approach 2:
Different regions of the plastic lens element are given different structural characteristics. The outer ring portion includes specific structures (such as positioning ribs, flat surfaces, and coaxial reference surfaces) that are tailored for precise positioning and mounting, while the optical effective portion maintains optical quality. This local differentiation enables both cost-effective injection molding and high manufacturing precision.
2Manufacturing precision
If the outer ring portion includes complex structures (annular grooves, conical surfaces, flat abutting portions), then assembly accuracy is improved, but device complexity increases
Solution Approach 1:
Multiple functions are merged into the outer ring portion of a single plastic lens element. The annular grooves provide positioning, the conical surfaces enable tapered mounting, the flat abutting portions ensure parallel alignment, and all these features are integrated into one injection-molded component. This merging reduces the need for separate parts and complex assembly processes while achieving high assembly accuracy.
Solution Approach 2:
The outer ring portion serves multiple purposes simultaneously: it provides structural support, ensures precise positioning through annular grooves, enables tapered mounting via conical surfaces, and guarantees parallel alignment through flat abutting portions. This multi-functionality reduces overall system complexity while maintaining high assembly accuracy.
Data Source
AI summary
An imaging lens system includes a plastic lens element. The plastic lens element includes an optical effective portion and an outer ring portion. The optical axis passes through the optical effective portion. The outer ring portion surrounds the optical effective portion and includes an annular groove structure, a conical surface, a flat abutting portion and a full-circle connecting portion. The annular groove structure is tapered off. Each of the conical surface and the flat abutting portion is located closer to the optical effective portion than the annular groove structure. The flat abutting portion is in physical contact with an optical element. The full-circle connecting portion is connected to the annular groove structure and located farther away from the optical effective portion than the annular groove structure. The annular groove structure has an annular bottom end surface extending in a direction substantially perpendicular to the optical axis.