Zoom Lens Relay Portion Extender Design
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Solution Overview
Problem
Existing zoom lens systems with high zoom ratios face challenges in maintaining high optical performance while minimizing the overall length of the relay portion, as increasing optical power in the extender units leads to aberration issues and difficulty in correcting for optical errors.
Innovation Solution
A zoom lens system with a relay portion comprising a fourth-first unit with negative optical power, a removable fourth-second unit, a fourth-third unit with positive optical power, and an extender fourth-fourth unit that shifts the focal length range, where specific optical axis distances and aperture diameters are optimized to balance system length and aberration correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the optical power of the front unit and rear unit in the extender is increased to reduce the entire length of the extender, then the entire length of the relay portion is reduced, but the aberration amount and high order aberration increase making it difficult to correct for aberration
Solution Approach 1:
The relay portion is divided into multiple lens units (first lens unit, second lens unit, third lens unit, fourth lens unit) with each unit having specific optical powers and functions. The extender is further segmented into a front unit and rear unit with specific optical power ratios. This segmentation allows each unit to be optimized independently for length and aberration control.
Solution Approach 2:
Different lens units are assigned different optical powers and characteristics tailored to their specific functions. The front unit of the extender has positive optical power while the rear unit has negative optical power, with their ratio controlled within specific ranges. Each unit's optical properties are locally optimized to achieve overall system compactness while maintaining aberration correction.
2Length of moving object
If the optical power of the front unit and rear unit in the extender is increased to reduce the entire length of the extender, then the entire length of the relay portion is reduced, but high optical performance cannot be maintained due to increased aberration
Solution Approach 1:
The patent establishes specific parameter ranges for the extender's optical configuration: the ratio of positive to negative optical power in the front and rear units is controlled within 0.5 to 2.0, and the ratio of the front unit's optical power to the entire extender's optical power is controlled within 0.3 to 0.7. These parameter constraints ensure compact length while maintaining optical performance within acceptable bounds.
3Ease of operation
If a space having a predetermined length is secured in the optical axis direction for inserting and removing the extender, then the extender can be properly installed, but the entire length of the relay portion increases
Solution Approach 1:
The second lens unit is designed to be movable along the optical axis, enabling dynamic adjustment of the optical path length. This movability allows the system to accommodate the extender's insertion and removal while maintaining a compact overall structure, as the lens unit can shift position to compensate for the extender's presence or absence.
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 solution effectively reduces the entire length of the relay portion while maintaining high optical performance in both standard and extender switched states, facilitating downsizing and improved aberration correction.
Implementation Method 1
a fourth-fourth unit which is inserted in the optical path for shifting a focal length range of an entire system to a long focal length side
Implementation Method 2
an aperture stop for light amount adjustment disposed between the zoom portion and the relay portion
Data Source
AI summary
Provided is a zoom lens including a focus lens portion, a zoom portion, an aperture stop, and a relay portion that does not move for zooming but comprises a negative fourth-first unit, a fourth-second unit interchangeable for an optical path, a positive fourth-third unit, and a fourth-fourth unit inserteable for the optical path for shifting a focal length range of an entire system to a long focal length side after removing the fourth-second unit from the optical path, and a distance on an optical axis between the aperture stop and a last lens surface of the fourth-fourth unit in a state of inserting the fourth-fourth unit in the optical path, a distance on the optical axis between a first lens surface and the last lens surface of the fourth-fourth unit, and an aperture diameter in an opened state of the aperture stop satisfy a predetermined conditions.