Projection Lens Group Back Focus and Centering Adjustment
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Solution Overview
Problem
In projector systems, particularly for short-throw projection, it is challenging to simultaneously perform back focus adjustment and centering of lenses, as the rotation mechanism for back focus adjustment often interferes with centering, leading to difficulties in maintaining optical performance and resolution.
Innovation Solution
A projection system incorporating a reduction side lens group with a feeding mechanism for rotary adjustment and a rotation angle adjustment mechanism that allows independent rotation, enabling precise back focus adjustment and centering without affecting the optical performance, utilizing a double frame structure and biasing members to maintain the rotation angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If back focus adjustment is performed by rotation of the fixed lens section, then the distance between the lens group and object plane can be adjusted, but the centering of the lens group cannot be adjusted independently
Solution Approach 1:
The patent divides the adjustment functions into two independent mechanisms: a feeding mechanism for back focus adjustment and a rotation angle adjustment mechanism for centering. This segmentation allows each function to be adjusted independently without interfering with the other, resolving the contradiction between back focus adjustment precision and centering operation difficulty.
Solution Approach 2:
The fixed lens section is designed to serve multiple functions: it can be adjusted for back focus through the feeding mechanism and for centering through the rotation angle adjustment mechanism. This multi-functionality allows a single component to handle both adjustment tasks independently, eliminating the need for separate mechanisms while maintaining operational independence.
2Manufacturing precision
If an aspheric lens is employed in the fixed lens section, then resolution and optical performance are improved, but the centering becomes critical and difficult to maintain during adjustment
Solution Approach 1:
The patent introduces a rotation angle adjustment mechanism that allows dynamic adjustment of the aspheric lens centering after assembly. This dynamic capability ensures that the critical centering of the aspheric lens can be maintained and fine-tuned even after the lens is installed, preserving optical performance while allowing for adjustments during assembly and maintenance.
Solution Approach 2:
The rotation angle adjustment mechanism is designed to be operable after the lens group is assembled into the projector. This preliminary action allows centering to be adjusted and optimized before final assembly, ensuring that the aspheric lens is properly centered while maintaining the ability to make corrections if needed.
3Device complexity
If a single rotation mechanism is used for back focus adjustment, then the structure is simplified, but both back focus adjustment and centering cannot be performed independently
Solution Approach 1:
The patent segments the adjustment mechanisms into two independent systems: a feeding mechanism with a first rotary member for back focus adjustment, and a rotation angle adjustment mechanism with a second rotary member for centering. This segmentation increases operational independence while keeping each individual mechanism relatively simple, resolving the contradiction between structural simplicity and independent adjustment capability.
Solution Approach 2:
The patent combines two adjustment functions (back focus and centering) into a single fixed lens section assembly, allowing both functions to be integrated in one component group. This merging maintains structural compactness while the independent rotation mechanisms ensure that both adjustments can be performed independently without interfering with each other.
Data Source
AI summary
A feeding mechanism is used to adjust the distance between a reduction side lens group and an object plane for back focus adjustment. A rotation angle adjustment mechanism capable of rotating action independent of rotating action performed in the back focus adjustment is used to adjust the rotation angle by which at least part of the reduction side lens group is rotated.