Super-Wide-Angle Zoom Lens Layout With Fixed Front Group
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Solution Overview
Problem
Existing super-wide-angle zoom lenses face challenges in sufficiently suppressing aberrational fluctuations associated with zooming and reducing the weight of the movable lens unit.
Innovation Solution
A zoom lens design comprising a first lens unit with negative refractive power and subsequent lens units, where the first lens unit is fixed, and the subsequent units move to change the distance between them, adhering to specific inequalities to ensure lightweight and maintain excellent optical performance across the zoom range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the first lens unit is fixed and subsequent lens units move for zooming, then the weight of the movable lens unit is reduced, but aberrational fluctuations associated with zooming cannot be sufficiently suppressed
Solution Approach 1:
The zoom lens is divided into multiple lens units (first lens unit with negative refractive power, second lens unit, third lens unit, and fourth lens unit). This segmentation allows the first lens unit to remain fixed while the subsequent units move independently during zooming, reducing the weight of movable components while maintaining aberration control through coordinated movement of multiple lighter segments rather than one heavy unit
Solution Approach 2:
The patent specifies particular parameter ranges including the inequality 0.3 < Tsw/fw < 0.6 at the wide-angle end, where Tsw is the distance from the object-side lens surface to the aperture stop and fw is the focal length at wide-angle end. These parameter optimizations ensure that the fixed first lens unit and moving subsequent units work together to suppress aberrational fluctuations while maintaining the lightweight design
2Adaptability or versatility
If the refractive power arrangement is retrofocus type with extreme negative refractive power on the front side, then super-wide-angle imaging is achieved, but various aberrations associated with magnification variation significantly fluctuate
Solution Approach 1:
The retrofocus-type refractive power arrangement is segmented into a fixed first lens unit with extreme negative refractive power and multiple subsequent lens units with positive refractive power. This segmentation allows the negative power front element to maintain the super-wide-angle capability while the subsequent positive power units are optimized to correct aberrations during zooming operations
Solution Approach 2:
Instead of moving the negative power front element during zooming (which would maintain aberration correction but increase weight), the patent inverts the approach by keeping the negative power unit fixed and moving the subsequent positive power units. This inversion achieves both weight reduction and aberration control through the coordinated movement of the positive power units compensating for the fixed negative power element
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 design achieves reduced weight of the movable lens unit and maintains excellent optical performance throughout the zoom range by effectively correcting aberrations.
Implementation Method 1
a first lens unit having negative refractive power
Implementation Method 2
a plurality of subsequent lens units... move to change a distance between adjacent lens units
Data Source
AI summary
A zoom lens includes, in order from an object side to an image side, a first lens unit having negative refractive power, and a plurality of subsequent lens units. The zoom lens further includes an aperture stop. For zooming, the first lens unit is fixed, and the plurality of subsequent lens units move to change a distance between adjacent lens units. Predetermined inequalities are satisfied.