Variable Focal Distance Lens System with Opposing Freeform Lenses
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Solution Overview
Problem
Existing zoom lenses face limitations in shortening overall lens length and achieving stable optical quality due to the complexity of processing and controlling multiple freeform-curved surface lenses, which are difficult to manufacture and position accurately.
Innovation Solution
A variable focal distance lens system comprising a first lens unit, a second lens unit with opposing freeform-curved surface lenses, and a third lens unit, where the first and third lens units are rotationally symmetrical and share the same shape, allowing the freeform-curved surface lenses to move in the Y-axis direction to adjust refractive power and cancel aberrations, while maintaining the image surface position constant.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If multiple freeform-curved surface lenses are used to achieve high magnification and compact size, then the lens system becomes smaller and more powerful, but manufacturing precision and optical stability deteriorate due to difficulty in processing and positioning these lenses
Solution Approach 1:
The patent employs freeform-curved surface lenses with asymmetric surfaces that lack rotational symmetry about the optical axis. This asymmetric design enables compact high-magnification capabilities while the patent addresses manufacturing challenges through specific configuration strategies. The first and second freeform-curved surface lenses are positioned to work in combination, where their asymmetric surfaces collectively achieve the desired optical performance despite individual lens positioning challenges.
Solution Approach 2:
The patent combines multiple freeform-curved surface lenses (first and second freeform-curved surface lenses) into a unified optical system where they work together to achieve high magnification. By merging these lenses into a coordinated arrangement within the lens barrel, the system achieves compact size while distributing the optical functions across multiple elements, which helps mitigate individual lens positioning errors.
2Adaptability or versatility
If freeform-curved surface lenses are moved independently to adjust magnification, then zooming flexibility is improved, but device complexity and control difficulty increase
Solution Approach 1:
The patent segments the lens system into distinct functional units: a first lens group with fixed lenses, a second lens group containing the movable freeform-curved surface lenses for zooming, and a third lens group for image surface compensation. This segmentation allows independent control of zooming function while simplifying the overall control mechanism, as each segment has a specific function rather than requiring coordinated movement of all lenses.
Solution Approach 2:
The patent implements dynamic zooming capability by enabling the second lens group containing the freeform-curved surface lenses to move along the optical axis. This dynamic arrangement allows continuous adjustment of magnification from wide-angle to telephoto ends. Additionally, the third lens group dynamically compensates for image surface position changes, maintaining focus throughout the zoom range.
3Length of stationary object
If conventional zoom lens design is used to maintain image surface position, then optical stability is improved, but lens length cannot be sufficiently shortened
Solution Approach 1:
The patent introduces freeform-curved surface lenses that operate in additional spatial dimensions beyond the traditional optical axis movement. These lenses have surfaces that vary in curvature across different zones, enabling focal length adjustment and image surface position compensation through movements in multiple directions. This dimensional approach allows compact lens length while maintaining image surface stability through the combined action of the second lens group (zooming) and third lens group (compensation).
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 results in a compact, high-magnification lens system with improved optical performance by reducing chromatic aberration and asymmetric aberration, while maintaining the image surface position constant, thus enhancing the zooming capability and reducing the size of the lens barrel.
Implementation Method 1
a refractive power of the second lens unit is variable due to the first freeform-curved surface lens and the second freeform-curved surface lens moving in opposite directions
Implementation Method 2
improved optical performance by reducing chromatic aberration and asymmetric aberration
Implementation Method 3
reducing chromatic aberration and asymmetric aberration
Data Source
AI summary
A first lens unit and a third lens unit are constituted by a lens which is rotationally symmetrical with respect to an optical axis and are disposed on the same optical axis, a first freeform-curved surface lens and a second freeform-curved surface lens have the same shape and are disposed to be rotated at 180 degrees with respect to the optical axis. Further, a refractive power of a second lens unit is variable due to the first freeform-curved surface lens and the second freeform-curved surface lens moving in opposite directions. The first freeform-curved surface lens and the second freeform-curved surface lens are moved in the Y-axis direction in association with movement of some of lens groups constituting the first lens unit and the third lens unit when positional states of the lenses are changed from a wide-angle end state to a telephoto end state.