Projection Lens Correction Group for Field Curvature
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Wide angle projection lenses face challenges in maintaining image quality when projection distance changes, particularly due to fastening errors and field curvature variations, which complicates focusing and requires independent correction of field curvature and focusing operations.
Innovation Solution
A projection lens design with a correction group that moves along the optical axis to adjust field curvature, maintaining constant conjugate length between lens groups, allowing independent magnification and focusing operations without causing defocusing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the focusing mechanism is used to absorb fastening errors, then the fastening error is corrected, but the focusing mechanism becomes overloaded and may cause troubles in wide angle lenses
Solution Approach 1:
The lens system is divided into multiple lens groups with specific functions: a correction group for field curvature correction and a focusing group for focusing. This segmentation allows the fastening error to be absorbed by the correction group's movement rather than overloading the focusing mechanism, resolving the contradiction between correcting fastening errors and maintaining focusing mechanism simplicity.
2Adaptability or versatility
If the projection distance is changed, then the projection distance is adjusted, but field curvature variation occurs requiring additional correction operations
Solution Approach 1:
The field curvature correction function is merged into the correction group that can move independently along the optical axis. When projection distance changes, the correction group automatically adjusts field curvature through its movement, combining the correction function with the distance adjustment mechanism and eliminating the need for separate correction operations.
3Manufacturing precision
If the conjugate length of the combined optical system is changed to correct field curvature, then field curvature is corrected, but defocusing occurs
Solution Approach 1:
The correction group is designed with specific optical characteristics (local quality) that allow it to correct field curvature while maintaining the conjugate length of the combined optical system constant. This local optimization ensures that field curvature correction does not cause defocusing, resolving the contradiction between correction precision and focus precision.
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
Enables precise correction of field curvature and inhibition of field curvature variation when absorbing fastening errors, simplifying focusing operations and maintaining image quality across varying projection distances.
Implementation Method 1
a correction group consisting of a plurality of lens groups that corrects field curvature by moving in an optical axis direction and changing the distance between each lens group
Implementation Method 2
a projection lens having a positive refractive power as a whole and including a correction group consisting of a plurality of lens groups that corrects field curvature
Data Source
AI summary
A projection lens is provided having a positive refractive power as a whole and including a correction group consisting of a plurality of lens groups that corrects field curvature by moving in an optical axis direction and changing the distance between each lens group. The conjugation length of a combined optical system combining the most magnification side lens group constituting the correction group to the most reduction side lens group constituting the correction group in the projection lens is constant before and after the movement of the correction group for correcting field curvature. If the projection lens is variable in magnification or focusable by moving at least some of the lens groups, the movement of the correction group for correcting field curvature is allowed to be performed independently of the movement for either changing magnification or focusing.