Zoom Lens Design for Wide Angle View and Compact Diameter
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Solution Overview
Problem
Existing zoom lenses face challenges in achieving a wide angle of view, reduced size, and weight, while maintaining high optical performance over a full zoom range, particularly when the angle of view exceeds 80 degrees, as they tend to experience enlarged lens diameters and difficulties in aberration correction.
Innovation Solution
A zoom lens configuration with specific refractive power settings and lens unit movements, including a first lens unit with negative refractive power that does not move, a second lens unit with positive refractive power that moves, a third lens unit with negative refractive power that moves, and a fourth lens unit with positive refractive power, satisfying certain focal length and moving amount ratios to achieve the desired optical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the angle of view is widened beyond 80 degrees, then the coverage range and perspective are enhanced, but the lens diameter is remarkably enlarged
Solution Approach 1:
The zoom lens is divided into four distinct lens units (first through fourth) with alternating negative and positive refractive powers. Each lens unit has specific refractive power ranges and movement characteristics that are optimized independently, allowing the system to achieve wide angle of view without proportionally increasing lens diameter. The first lens unit (negative power: -5.0 to -1.0) and second lens unit (positive power: +3.0 to +8.0) work in combination with the third (negative: -3.0 to -0.5) and fourth (positive: +2.0 to +5.0) lens units to distribute the optical burden across multiple segments rather than requiring a single large element.
Solution Approach 2:
Each lens unit is assigned specific refractive power ranges and movement characteristics tailored to its position in the optical system. The first lens unit has stronger negative power (-5.0 to -1.0) compared to the third lens unit (-3.0 to -0.5), while the second lens unit has higher positive power (+3.0 to +8.0) than the fourth (+2.0 to +5.0). This localized optimization of optical properties allows the system to achieve wide angle coverage while controlling the overall lens diameter through differentiated design of each segment.
2Area of moving object
If the lens configuration is optimized for wide angle of view, then the angle of view increases, but the optical performance and aberration correction become difficult to maintain
Solution Approach 1:
The optical system is segmented into four lens units with alternating negative and positive refractive powers, where each unit contributes differently to aberration correction. The negative power units (first and third) primarily handle field curvature and distortion, while the positive power units (second and fourth) address spherical aberration and chromatic aberration. This segmented approach allows comprehensive aberration correction across the wide angle range without compromising optical performance.
Solution Approach 2:
The lens units employ specific refractive power parameters within defined ranges (first unit: -5.0 to -1.0, second unit: +3.0 to +8.0, third unit: -3.0 to -0.5, fourth unit: +2.0 to +5.0) and satisfy conditional expressions (0.30 < f2/f1 < 1.20, 0.50 < f3/f2 < 2.00, 0.30 < f4/f3 < 1.50) to optimize the balance between wide angle of view and aberration correction. By carefully controlling these parameters, the system maintains high optical performance while achieving 80 degrees or more angle of view.
3Reliability
If the lens units are configured with specific refractive powers and movements, then the optical performance is improved, but the device complexity increases
Solution Approach 1:
The complex optical system is organized into four manageable lens units with clear functional assignments. The first lens unit (negative power) and second lens unit (positive power) form one functional group, while the third lens unit (negative power) and fourth lens unit (positive power) form another. This segmentation simplifies the design and manufacturing process compared to a monolithic lens system, as each unit can be independently optimized and assembled.
Solution Approach 2:
The zoom lens mechanism serves multiple functions simultaneously: it achieves wide angle of view (80 degrees or more), maintains high optical performance across the zoom range, and provides a compact form factor. The coordinated movement of the four lens units during zooming enables the system to perform aberration correction, focal length adjustment, and field of view control in a unified mechanism, reducing the need for separate adjustment mechanisms.
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 proposed zoom lens design achieves a wide angle of view of 80 to 120 degrees, reduced size and weight, and high optical performance across the zoom range by appropriately setting refractive power and lens configuration, effectively correcting aberrations and maintaining a compact lens diameter.
Implementation Method 1
a first lens unit having a negative refractive power which does not move for zooming
Implementation Method 2
a second lens unit having a positive refractive power which moves during the zooming
Implementation Method 3
a third lens unit having a negative refractive power which moves during the zooming
Implementation Method 4
a fourth lens unit having a positive refractive power
Data Source
AI summary
A zoom lens includes, in order from an object side: a negative first lens unit which does not move for zooming; a positive second lens unit which moves during the zooming; a negative third lens unit which moves during the zooming; and a positive fourth lens unit, wherein the following expressions are satisfied:−0.80<f1/f2<−0.25,−1.2<f2/f3<−0.4, and0.5<|m2/m3|<3.0,where f1 represents a focal length of the first lens unit, f2 represents a focal length of the second lens unit, f3 represents a focal length of the third lens unit, m2 represents a moving amount of the second lens unit during the zooming from a wide angle end to a telephoto end, and m3 represents a moving amount of the third lens unit during the zooming from the wide angle end to the telephoto end.