Intermediate-Image Optical Layout for Stable Wide-Angle Focusing
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Solution Overview
Problem
Wide-angle imaging optical systems face issues with aberration fluctuation, such as field curvature aberration and astigmatism, during focus adjustment, leading to degraded optical performance, and existing focus mechanisms are either heavy or require multiple moving groups, increasing complexity.
Innovation Solution
An optical system with an intermediate imaging position conjugate to both magnification and reduction sides, featuring a first positive lens group and a negative lens group that move during focusing, while a second positive lens group remains stationary, facilitating easier focus adjustment and reducing the size and weight of the focus mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If focus adjustment is performed using two focus groups on the magnification side, then the center of gravity is positioned on the magnification side, but fluctuation of off-axis curvature of field reaches about 0.05 mm degrading optical performance
Solution Approach 1:
The optical system divides the focusing function across three distinct lens groups (first positive, second positive, and negative lens groups) positioned at different locations relative to the intermediate image. This segmentation allows each group to contribute differently to focus adjustment, enabling better control of field curvature aberration while maintaining ease of operation.
Solution Approach 2:
Different lens groups are assigned different roles in the focusing mechanism. The first positive lens group moves during focusing, the second positive lens group remains stationary, and the negative lens group moves during focusing. This local differentiation of functionality optimizes the focusing performance and reduces field curvature fluctuation.
2Manufacturing precision
If two or three focus groups are used for focus adjustment, then optical performance improves, but device complexity and weight increase due to multiple actuators
Solution Approach 1:
The patent combines the focusing function into a coordinated system where the first positive lens group and negative lens group move together during focusing, while the second positive lens group remains stationary. This merging of movement patterns reduces the number of independent actuators needed compared to using three separate focus groups, thereby reducing device complexity and weight while maintaining good optical performance.
Solution Approach 2:
The second positive lens group serves a dual role: it is positioned between the first positive lens group and the intermediate image, and it remains stationary during focusing. This stationary group contributes to image quality correction while the other groups handle focus adjustment, reducing the overall complexity of the focusing mechanism.
3Area of stationary object
If wide-angle projection is achieved with short focal length, then screen coverage is improved, but aberration fluctuation increases during focus adjustment
Solution Approach 1:
The optical system employs a dynamic focusing mechanism where specific lens groups (first positive and negative) move during focusing while others remain stationary. This dynamic configuration allows the system to maintain wide-angle projection capability with short focal length while actively compensating for aberration fluctuations that occur during focus adjustment.
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 system achieves improved focus adjustment with reduced weight and size, minimizing aberration fluctuation and enhancing optical performance by optimizing the movement of lens groups, thereby simplifying the focus mechanism.
Implementation Method 1
a first positive lens group GP1 including a plurality of lens elements and positioned on a magnification side with respect to an intermediate imaging position MI... a second positive lens group GP2 including a plurality of lens elements and positioned between the first positive lens group GP1 and the intermediate imaging position MI... a negative lens group GN including a plurality of lens elements and positioned on a reduction side with respect to the intermediate imaging position MI
Data Source
AI summary
The present disclosure is directed to an optical system internally having an intermediate imaging position MI that is conjugate with both of a magnification conjugate point on a magnification side and a reduction conjugate point on a reduction side, the optical system including: a first positive lens group GP1 including a plurality of lens elements and positioned on the magnification side with respect to the intermediate imaging position; a second positive lens group GP2 including a plurality of lens elements and positioned between the first positive lens group GP1 and the intermediate imaging position M1; and a negative lens group GN including a plurality of lens elements and positioned on the reduction side with respect to the intermediate imaging position MI, wherein, during focusing, the first positive lens group GP1 and the negative lens group GN move in an optical axis direction, and the second positive lens group GP2 is stationary.