Zoom Lens Extender Integration for Compact Aberration Control
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Solution Overview
Problem
Existing zoom lenses with large aperture diameters and long focal lengths face challenges in maintaining good optical performance when an extender is inserted, often requiring large air gaps and improper positioning, leading to increased size and difficulty in correcting aberrations.
Innovation Solution
A zoom lens design with specific refractive power relationships between lens units, allowing for an extender to be easily inserted while maintaining optical performance, including a configuration that satisfies inequalities to control the distance and focal lengths of lens units, and a detachable extender with multiple cemented lenses for aberration correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a large air gap is provided to insert the extender into the optical path, then the extender can be inserted, but the overall lens length increases and the structure becomes larger
Solution Approach 1:
The patent makes the air gap dynamic by allowing the fourth lens unit to move independently during focusing operations. This creates a variable space between the fourth lens unit and the fixed rear lens unit, enabling the extender to be inserted into this dynamically adjusted gap without requiring a permanently large air gap, thus resolving the contradiction between extender insertability and compact lens length
Solution Approach 2:
The patent divides the focusing function across multiple lens units (fourth lens unit moves for focusing, fifth lens unit remains fixed). This segmentation allows the fourth lens unit to create the necessary variable air gap for extender insertion while the fifth lens unit maintains optical performance, enabling extender compatibility without compromising optical quality or increasing overall size
2Device complexity
If the position of the extender insertion is not proper, then the lens structure becomes large, but optical performance deteriorates
Solution Approach 1:
The patent introduces the fourth lens unit as an intermediary element between the third and fifth lens units. This intermediary can move to create the necessary air gap for extender insertion while maintaining proper optical positioning. The fourth lens unit acts as a mediator that enables extender integration at the optimal position without compromising optical performance or requiring an oversized lens structure
Solution Approach 2:
The movable fourth lens unit creates a dynamic positioning system that allows the extender to be inserted at the proper optical position. By adjusting the position of the fourth lens unit, the system maintains optimal optical performance while accommodating the extender, avoiding both oversized structure and performance degradation
3Device complexity
If refractive powers of lens units are not properly set, then the lens structure becomes simpler, but optical performance before and after extender insertion deteriorates
Solution Approach 1:
The patent carefully optimizes the refractive power parameters of each lens unit (first: positive, second: negative, third: positive, fourth: negative, fifth: positive). These specific parameter settings enable the system to maintain consistent optical performance before and after extender insertion. The balanced distribution of positive and negative refractive powers across the five lens units creates a stable optical system that accommodates the extender without performance degradation
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 enables a zoom lens that can change focal length ranges easily with an extender, while keeping a compact size and ensuring good optical performance throughout the zoom range, with effective aberration correction.
Implementation Method 1
a zoom lens according to the disclosure consists of, in order from an object side to an image side, a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, and a rear group including a plurality of lens units
Implementation Method 2
a first cemented lens having a negative refractive power and consisting of a negative lens, a positive lens, and a negative lens, and a second cemented lens having a negative refractive power and consisting of a negative lens, a positive lens, and a negative lens
Data Source
AI summary
A zoom lens consists of, in order from an object side to an image side, a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, and a rear group including a plurality of lens units. A distance between adjacent lens units is changed during zooming. The rear group includes a diaphragm, an n-th lens unit disposed closest to an image plane and having a positive refractive power, and an (n−1)-th lens disposed on the object side of the n-th lens unit and having a negative refractive power. A predetermined condition is satisfied.