Zoom Lens Stationary First Unit Aberration Control
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Solution Overview
Problem
Existing zoom lenses face challenges in reducing chromatic aberration while maintaining high image quality and compact size, particularly in achieving a wide angle and large magnification with good optical properties.
Innovation Solution
A zoom lens configuration with specific refractive power arrangements and movement ratios between lens units, including a first lens unit with positive refractive power that does not move, a second lens unit with negative refractive power, and intermediate and rear lens groups with varying intervals, satisfying conditional expressions to correct aberrations and reduce size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a zoom lens uses multiple movable lens units to achieve a wide angle and large magnification, then the zoom ratio and field of view are improved, but the chromatic aberration varies significantly during zooming
Solution Approach 1:
The zoom lens is divided into five distinct lens units (L1-L5) with different refractive powers, where each unit has a specific function. The first lens unit (L1) with positive refractive power remains stationary during zooming, while the other units move to achieve zooming. This segmentation allows the stationary L1 to provide a fixed optical reference that helps maintain consistent chromatic aberration correction across the zoom range.
Solution Approach 2:
Each lens unit is designed with specific optical properties (refractive power, focal length) tailored to its position and function. The first lens unit L1 has a positive refractive power and is specifically designed not to move during zooming, creating a stable optical zone that anchors the chromatic aberration correction while other units move to provide zoom functionality.
2Length of moving object
If the first lens unit is made movable to achieve compact size, then the total length is reduced, but the chromatic aberration control deteriorates
Solution Approach 1:
Instead of making all lens units movable to achieve compactness, the invention inverts the conventional approach by making the first lens unit (L1) stationary while allowing subsequent units to move. This reversal creates a stable optical reference point at the front of the system, which helps maintain consistent chromatic aberration correction while still enabling zoom functionality through the movement of other units.
3Volume of moving object
If lens units are made small in diameter to reduce overall size, then the device becomes more compact, but the optical performance and aberration correction are compromised
Solution Approach 1:
Each lens unit is designed with specific optical properties (refractive power, focal length, diameter) optimized for its particular position and function in the zoom system. The first lens unit L1 has a positive refractive power and is designed with appropriate diameter to provide stable chromatic aberration correction, while other units have dimensions optimized for their specific zoom functions.
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 achieves a small size, wide angle, large magnification, and effective correction of chromatic aberration, ensuring good optical properties across the zoom range.
Implementation Method 1
a first lens unit L1 having a positive refractive power, a second lens unit L2 having a negative refractive power, a third lens unit L3 having a positive refractive power, a fourth lens unit L4 having a negative refractive power, and a fifth lens unit L5 having a positive refractive power which are arranged in order from the object side to the image side
Data Source
AI summary
A zoom lens includes, in order from an object side, a positive first unit, a negative second unit, a positive intermediate group consisting of one or two units and including a third unit located on a most object side, a negative unit, and a rear group consisting of one or two units including a positive unit located on a most object side. Conditional expressions are satisfied with respect to amounts of movement of the second and third units from a wide angle end to a telephoto end, a distance at the wide angle end from a most object side surface vertex in the first unit to a most object side surface vertex in the third unit, an Abbe number of a most object side lens in the first unit, a focal length of the second unit, and focal lengths at the wide angle end and at the telephoto end.