Zoom Lens Segmented First Unit for Compact High Magnification
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Solution Overview
Problem
Conventional zoom lenses face challenges in achieving high magnification while maintaining a small size and light weight, along with minimizing aberration deviation during focus adjustment, especially for television and motion-picture cameras.
Innovation Solution
The zoom lens design includes a first lens unit with positive refractive power that does not move, a magnification-varying lens unit with two moving lens units, and an imaging lens unit with positive refractive power that does not move, where the second sub-lens unit moves towards the object side for focus adjustment, satisfying specific conditional expressions to suppress aberration deviation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the first lens unit diameter or entire length is increased to achieve high magnification, then magnification is improved, but device size and weight increase
Solution Approach 1:
The first lens unit is divided into three sub-lens units (first, second, and third) with different refractive powers. This segmentation allows each sub-unit to have optimized dimensions and refractive properties, achieving high magnification through coordinated action of smaller components rather than requiring a single large lens unit.
Solution Approach 2:
The patent applies specific conditional expressions that define relationships between focal lengths and distances (e.g., 0.3 < f1/ft < 0.6, 0.05 < d1/f1 < 0.3). By controlling these parameters, the system achieves high magnification while maintaining compact dimensions and reduced weight through optimized optical path design.
2Adaptability or versatility
If the first lens unit diameter or entire length is increased to achieve high magnification, then magnification is improved, but device size increases
Solution Approach 1:
Dividing the first lens unit into three sub-lens units allows the optical system to achieve high magnification through a more compact arrangement. The segmented structure enables better control of light paths and reduces the overall length required compared to a single large lens unit.
Solution Approach 2:
The patent utilizes the degree of freedom in moving individual sub-lens units independently along the optical axis. This dimensional control allows optimization of the optical path length and focusing mechanism, achieving high magnification with reduced overall lens length.
3Ease of operation
If conventional focus adjustment methods are used, then focus adjustment is achieved, but aberration deviation increases
Solution Approach 1:
Different sub-lens units within the first lens unit have different refractive powers and are designed with specific local optical properties. The second sub-lens unit, in particular, is optimized for focus adjustment functionality. This local optimization allows focus adjustment while maintaining low aberration deviation.
Solution Approach 2:
The patent defines conditional expressions that constrain the relationship between focal lengths and distances (e.g., 0.05 < d1/f1 < 0.3, where d1 is the moving distance of the second sub-lens unit). These parameter constraints ensure that focus adjustment produces minimal aberration deviation by controlling the movement characteristics of the second sub-lens unit.
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 design achieves a high-performance zoom lens with high magnification, small size, and light weight, while effectively minimizing aberration deviation due to focus adjustment, enabling improved optical performance for cameras.
Implementation Method 1
a first lens unit having positive refractive power, a second lens unit having negative refractive power, and a third lens unit having positive refractive power
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
A zoom lens includes, in order from an object side: a first lens unit having positive refractive power which does not move for varying magnification; a magnification-varying lens unit including at least two lens units which move for varying magnification; an aperture stop; and an imaging lens unit having positive refractive power which does not move for varying magnification, in which: the first lens unit includes, in order from the object side, a first sub-lens unit having positive refractive power, a second sub-lens unit having negative refractive power, and a third sub-lens unit having positive refractive power; the second sub-lens unit is driven to the object side so as to perform focus adjustment to an object at a short distance; and the following expression is satisfied: 0.07<f1/f11<0.35, where f1 represents a focal length of the first lens unit, and f11 represents a focal length of the first sub-lens unit.