Fixed-Focus Lens With Reflective Mirror and Positive Lens Groups
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Solution Overview
Problem
Designing a projection lens that balances lower production cost with better optical characteristics, while addressing aberration issues and assembly complexity, is a significant challenge in the field of fixed-focus lenses.
Innovation Solution
A fixed-focus lens is designed with a reflective system and a refractive system, including a reflection mirror with negative refractive power and two lens groups with positive refractive powers, allowing for a broader angle of view, improved imaging quality, and reduced assembly difficulty at a lower cost, with the lens architecture satisfying F/H > 0.23.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a reflection mirror is used to shorten the focal length and reduce aberration, then the angle of view is improved, but the production cost and assembly difficulty increase
Solution Approach 1:
The patent merges the reflection mirror with the lens groups into a single integrated optical system. The reflection mirror is positioned within the lens assembly rather than as a separate component, allowing the light to reflect and pass through multiple lens groups in sequence. This integration maintains the wide angle of view benefit while reducing assembly complexity compared to using multiple separate reflection mirrors.
Solution Approach 2:
The optical system is segmented into distinct functional groups: the reflection mirror for wide-angle light collection, the first lens group for initial focusing, and the second lens group for final image formation. This segmentation allows each component to be optimized for its specific function while being assembled as a coordinated system, reducing overall assembly difficulty.
2Manufacturing precision
If more lenses are used to reduce aberration, then the imaging quality is improved, but the production cost increases
Solution Approach 1:
The patent applies aspheric surfaces specifically to the reflection mirror and selected lens surfaces where they are most effective at correcting aberration. Rather than making all surfaces aspheric (which would increase cost), the aspheric quality is applied locally to the surfaces that provide the greatest aberration correction benefit, optimizing the balance between imaging quality and manufacturing cost.
Solution Approach 2:
The optical system uses a composite design combining spherical and aspheric surfaces, reflection and refraction mechanisms, and multiple lens materials with different refractive indices. This composite approach allows aberration correction through multiple mechanisms working together, reducing the need for an excessive number of lenses while maintaining high imaging quality.
3Length of moving object
If multiple reflection mirrors are used to shorten projection distance, then the projection distance is reduced, but the production cost increases
Solution Approach 1:
The patent combines the function of shortening projection distance with the existing lens groups by integrating a single reflection mirror into the optical path. The reflected light passes through the first and second lens groups which are already present in the system, eliminating the need for additional reflection mirrors that would be required in conventional designs. This merging of functions reduces both production cost and assembly complexity while achieving the short projection distance goal.
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
The solution achieves a broader angle of view, good imaging quality, and lower production costs by simplifying the lens design with a reflective and refractive system, effectively reducing aberrations and assembly complexity.
Implementation Method 1
a reflection mirror with a negative refractive power
Implementation Method 2
a first lens group and a second lens group, the first lens group having a positive refractive power, the second lens group being disposed between the first lens group and the minified side and having a positive refractive power
Data Source
AI summary
A fixed-focus lens disposed between a magnified side and a minified side. The fixed-focus lens has an optical axis and includes a reflective system and a refractive system. The reflective system includes a reflection mirror with a negative refractive power. The refractive system is disposed between the reflection mirror and the minified side and includes a first lens group and a second lens group. The first lens group has a positive refractive power. The second lens group is disposed between the first lens group and the minified side, and has a positive refractive power. The fixed-focus lens satisfies F/H>0.23, where F is an effective focal length and H is an image height.