Zoom Optical System with Dual Focus Groups for Angle-of-View Stability
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Solution Overview
Problem
Conventional zoom optical systems experience significant variation in angle of view during focusing operations, which is not adequately addressed by existing technologies.
Innovation Solution
The zoom optical system comprises a front and rear lens group configuration where the rear group includes a first and second focusing lens group, with specific conditional expressions defining their magnifications and movements along the optical axis to minimize angle of view variation during focusing, and includes a method for manufacturing such systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional zoom optical systems are used, then the system structure is simple, but the variation in angle of view upon focusing is significant
Solution Approach 1:
The rear group is divided into two separate focusing lens groups (first focusing lens group and second focusing lens group) instead of using a single focusing group. This segmentation allows independent control of each group's movement trajectory, enabling precise compensation for angle of view variation while maintaining manageable system complexity
Solution Approach 2:
The patent implements dynamic movement trajectories for the first and second focusing lens groups during focusing operations. The groups move along different trajectories that are specifically designed to compensate for angle of view changes, allowing the system to adaptively maintain consistent angle of view across different focus distances
2Device complexity
If the front group is fixed with respect to the image surface during focusing, then the focusing mechanism is simplified, but the rear focusing lens groups must move on complex different trajectories
Solution Approach 1:
The rear group is segmented into two focusing lens groups that can be controlled independently. This segmentation transforms the complex problem of single-group multi-trajectory control into two simpler, coordinated control tasks, making the system easier to operate while maintaining the fixed front group configuration
Solution Approach 2:
The second focusing lens group acts as an intermediary element that compensates for angle of view variations caused by the first focusing lens group's movement. This intermediary relationship allows the system to achieve complex optical compensation through coordinated movement of two groups rather than requiring complex control of a single group
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
This configuration effectively reduces variation in angle of view upon focusing, enhancing the performance and optical quality of the zoom optical system.
Implementation Method 1
a zoom optical system consists of, in order from an object along an optical axis: a front group; and a rear group
Data Source
AI summary
A variable magnification optical system (ZL) comprises a front group (GA) and a rear group (GB). The rear group (GB) has a first focusing lens group (GF1) and a second focusing lens group (GF2). From focusing on an object at infinity to focusing on a short-distance object, the front group (GA) is fixed with respect to an image surface, and the first focusing lens group (GF1) and the second focusing lens group (GF2) move on different trajectories along an optical axis. The variable magnification system satisfies the following conditional expressions.0.25<βF1t/βF1w<2.000.25<βF2w/βF2t<2.00where βF1t is the magnification of the first focusing lens group (GF1) in a telephoto end state, βF1w is the magnification of the first focusing lens group (GF1) in a wide-angle end state, βF2t is the magnification of the second focusing lens group (GF2) in the telephoto end state, and βF2w is the magnification of the second focusing lens group (GF2) in the wide-angle end state.