Zoom Optical System Front Group Dynamics for Aberration Control
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Solution Overview
Problem
Prior art zoom optical systems have not achieved excellent optical performance, particularly in film cameras, digital still cameras, and video cameras due to limitations in refracting power distribution and lens group movements during zooming and focusing.
Innovation Solution
A zoom optical system comprising a first lens group with positive refracting power, a second lens group with negative refracting power, a third lens group with positive refracting power, and a fourth lens group with positive refracting power, where at least one of these groups includes a front group with positive refracting power and a rear group with negative refracting power, with the distance between the front and rear groups remaining constant during zooming, and the front lens group moving along the optical axis for focusing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the distance between the front group and rear group changes during zooming, then the optical system can be more compact, but spherical aberration increases and optical performance deteriorates
Solution Approach 1:
The patent applies dynamics by making the front group movable along the optical axis during focusing operations. This allows the optical system to adapt its configuration dynamically - keeping the front group and rear group at a constant distance during zooming to maintain aberration correction, while enabling focusing movement when needed. The movable front group design resolves the contradiction by providing conditional mobility rather than fixed positioning.
2Ease of operation
If the front lens group moves along the optical axis for focusing, then focusing capability is improved, but the optical system becomes more complex
Solution Approach 1:
The patent applies segmentation by dividing the optical system into distinct functional groups: a movable front group for focusing and a rear group that remains stationary during focusing. This segmentation allows the focusing function to be isolated to a specific component, simplifying the control mechanism compared to moving the entire optical system. The front group's independent movability provides focusing capability without requiring complex adjustments throughout the entire optical train.
3Device complexity
If prior art zoom optical system configurations are used, then device simplicity is maintained, but optical performance is insufficient
Solution Approach 1:
The patent applies local quality by optimizing specific regions of the optical system rather than applying uniform design principles throughout. The front group is specifically designed with particular refractive power characteristics and is positioned to handle specific portions of the optical path. This localized optimization of the front group's properties (positive refractive power, specific movement characteristics) enables superior overall optical performance without requiring complete redesign of the entire system.
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 enhances optical performance by reducing spherical aberration, minimizing manufacturing errors, and maintaining a compact optical system design while ensuring excellent correction of aberrations at short object distances.
Implementation Method 1
a first lens group having a positive refracting power, a second lens group having a negative refracting power, a third lens group having a positive refracting power, and a fourth lens group having a positive refracting power
Data Source
AI summary
A zoom optical system includes, in order from its object side along its optical axis, a first lens group G1 having a positive refracting power, a second lens group G2 having a negative refracting power, a third lens group G3 having a positive refracting power, and a fourth lens group G4 having a positive refracting power, wherein at least one of the first, second, third and fourth lens groups G1, G2, G3, G4 comprises a front group having a positive refracting power including at least two lenses and a rear group having a negative refracting power, and during zooming from the wide angle end state W to the telephoto end state T, the distance between the front group and the rear group does not change, and during focusing onto an object, the front group moves along the optical axis.