Wide-Angle Zoom Lens Structure for Lightweight Off-Axis Correction
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Solution Overview
Problem
Existing zoom lenses for image pickup apparatuses face challenges in achieving a wide angle of view while maintaining a small and lightweight configuration, with significant off-axis aberrations such as curvature of field and distortion, and insufficient optical performance.
Innovation Solution
A zoom lens design that includes a first lens unit with negative refractive power, a second lens unit with positive refractive power, and a rear unit with one or more lens units, where the focal length and refractive index of the negative lenses are carefully set to satisfy specific inequalities, allowing for weight reduction and improved optical performance through the use of electronic aberration correction technology.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If a negative lead type zoom lens is used to achieve wide angle of view, then the angle of view is improved, but the lens unit becomes larger and heavier
Solution Approach 1:
The patent applies parameter changes by carefully controlling the focal length ratio (0.05 < fG1/fG2 < 0.30) and refractive index (1.8 < ndG1 < 2.2) of the negative lenses. This optimization allows the first lens unit to achieve wide angle of view while reducing its size and weight compared to conventional designs.
Solution Approach 2:
The patent uses composite lens designs combining negative lenses with different refractive indices and dispersion properties. The first lens unit includes a negative lens G1 and negative lens G2 with specifically controlled optical parameters, creating a composite structure that reduces weight while maintaining wide angle performance.
2Weight of moving object
If the lens unit is made smaller and lighter, then the portability is improved, but off-axis aberrations such as curvature of field and distortion increase
Solution Approach 1:
The patent controls off-axis aberrations through precise parameter optimization: the focal length ratio (0.05 < fG1/fG2 < 0.30) and refractive index (1.8 < ndG1 < 2.2) of the negative lenses are specifically set to balance miniaturization with aberration correction, enabling small size while maintaining optical quality.
Solution Approach 2:
The patent applies local quality by using negative lenses with different refractive indices and dispersion characteristics in specific positions within the first lens unit. This localized optimization of optical properties corrects off-axis aberrations in the miniaturized lens structure without compromising overall compactness.
3Duration of action of moving object
If the first lens unit is optimized for wide angle, then the angle of view is improved, but the optical performance deteriorates due to insufficient aberration correction
Solution Approach 1:
The patent achieves both wide angle of view and high optical performance through comprehensive parameter optimization. The focal length ratio (0.05 < fG1/fG2 < 0.30) and refractive index (1.8 < ndG1 < 2.2) are carefully controlled to ensure proper aberration correction while maintaining wide angle capability across the zoom range.
Solution Approach 2:
The patent employs composite lens construction in the first lens unit, combining negative lenses with different optical properties (refractive indices and dispersion). This composite structure enables simultaneous achievement of wide angle of view and high optical performance by correcting various aberrations through the synergistic effect of different lens materials.
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 achieves a small and lightweight zoom lens with high optical performance across the entire zoom range, effectively correcting aberrations and enabling image stabilization through parallel decentering of lens units, while reducing the size and weight of the lens.
Implementation Method 1
a first lens unit having negative refractive power, a second lens unit having positive refractive power
Data Source
AI summary
A zoom lens includes, in order from an object side to an image side, a first lens unit having negative refractive power, a second lens unit having positive refractive power, and a rear unit including one or more lens units. A distance between adjacent lens units changes during zooming. The rear unit includes a focus lens unit having positive refractive power and configured to move from the image side to the object side during focusing from infinity to a short-distance end. The first lens unit includes, in order from the object side to the image side, a first negative lens and a second negative lens. A predetermined condition is satisfied.