Zoom Optical System Aberration Correction via Segmented Focusing Lens
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Solution Overview
Problem
Conventional zoom optical systems lack sufficient reduction in the weight of the focusing lens group, which affects the camera's performance in terms of speed and silence during autofocus and aberration correction.
Innovation Solution
A zoom optical system comprising a front lens group with positive refractive power, an M1 lens group with negative refractive power, an M2 lens group with positive refractive power, and an RN lens group with negative refractive power, where the distances between these groups change upon zooming, and the RN lens group moves upon focusing, with the M2 lens group satisfying a specific focal length ratio condition to optimize aberration correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the focusing lens group weight is reduced, then autofocus speed and silence are improved, but aberration correction capability deteriorates
Solution Approach 1:
The focusing lens group is segmented into multiple sub-groups (first focusing lens group and second focusing lens group) with different refractive powers. The first focusing lens group has positive refractive power while the second has negative refractive power. This segmentation allows independent optimization of each sub-group's contribution to both weight reduction and aberration correction, resolving the contradiction between lightweight design and optical performance.
Solution Approach 2:
Different regions within the focusing lens group are assigned different optical properties. The first focusing lens group uses positive refractive power elements while the second uses negative refractive power elements. This local differentiation of optical characteristics enables precise control over aberration correction in specific zones while maintaining overall weight reduction, addressing both requirements simultaneously.
2Object-generated harmful factors
If the focusing lens group weight is reduced, then autofocus silence is improved, but optical performance deteriorates
Solution Approach 1:
By dividing the focusing lens group into multiple sub-groups with different refractive powers, the patent reduces the total mass of glass required while maintaining optical performance. The distributed architecture allows each sub-group to contribute minimally to weight while collectively providing sufficient aberration correction, thereby achieving quiet autofocus without sacrificing optical quality.
Solution Approach 2:
The patent employs composite optical structures combining positive and negative refractive power elements in a unified focusing lens group. This composite approach optimizes the balance between material usage (weight) and optical function (aberration correction), enabling lightweight design that maintains high optical performance and produces minimal autofocus noise.
3Reliability
If the lens barrel size is increased, then aberration correction is improved, but device compactness deteriorates
Solution Approach 1:
The patent employs dynamic movement of the focusing lens group along the optical axis to achieve focusing from infinity to short distances. The first and second focusing lens groups move cooperatively to maintain optimal spacing and optical alignment throughout the focusing range. This dynamic configuration enables effective aberration correction across all focus distances without requiring increased lens barrel length, as the optical performance is maintained through intelligent motion control rather than physical size expansion.
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 reduces the size and weight of the focusing lens group, enabling high-speed autofocus and silence without increasing the lens barrel size, while effectively suppressing aberrations during zooming and focusing, thereby enhancing optical performance.
Implementation Method 1
a front lens group having a positive refractive power; an M1 lens group having a negative refractive power; an M2 lens group having a positive refractive power; and an RN lens group having a negative refractive power
Data Source
AI summary
A zoom optical system comprises, in order from an object: a front lens group (GFS) having a positive refractive power; an M1 lens group (GM1) having a negative refractive power; an M2 lens group (GM2) having a positive refractive power; and an RN lens group (GRN) having a negative refractive power, wherein upon zooming, distances between the front lens group and the M1 lens group, between the M1 lens group and the M2 lens group, and between the M2 lens group and the RN lens group change, upon focusing from an infinite distant object to a short distant object, the RN lens group moves, and the M2 lens group comprises an A lens group that satisfies a following conditional expression, 1.10<fvr/fTM2<2.00, where, fvr: a focal length of the A lens group, and fTM2: a focal length of the M2 lens group in a telephoto end state.