Compact High-Power Zoom Lens Aberration Control
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Solution Overview
Problem
Existing high-power zoom lenses face challenges in achieving a zoom ratio of 24 to 34 times while maintaining miniaturization and suppressing axial chromatic and spherical aberrations, as well as minimizing moving distances of movable groups.
Innovation Solution
A four-group zoom lens configuration where the first and third groups are fixed, and the second and fourth groups are moved along the optical axis to compensate for imaging position fluctuations, with specific refractive power and lens configurations in each group to achieve a compact and high-power design, including a three-group four-lens configuration for the first and second groups and a two-group two-lens configuration for the third group, and a two-group three-lens configuration for the fourth group.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the zoom ratio is increased to 24-34 times, then the imaging range is widened, but the axial chromatic aberration and spherical aberration increase
Solution Approach 1:
The zoom lens is divided into four distinct groups (first group with positive refractive power, second group with negative refractive power, third group with positive refractive power, and fourth group with positive refractive power), with each group containing specific lens elements configured to address different aberration types. This segmentation allows independent optimization of each group to control aberrations across the high zoom ratio range.
Solution Approach 2:
Specific lens elements within each group are assigned particular refractive powers and positions to address local aberration problems. For example, the second group's negative refractive power elements are positioned to correct chromatic aberration, while the fourth group's elements are configured to correct spherical aberration at the telephoto end, giving different parts of the system different functional qualities.
2Adaptability or versatility
If the power is increased to achieve higher zoom ratio, then the imaging range is expanded, but the moving distances of movable groups increase
Solution Approach 1:
The lens system employs dynamic movement of the second and fourth groups along the optical axis during zooming, with the second group moving to perform zooming and the fourth group moving to compensate for imaging position fluctuations. This dynamic configuration allows the system to achieve high zoom ratio while controlling moving distances through coordinated group movements.
3Reliability
If the aberration is suppressed to maintain optical performance, then the image quality is improved, but the lens complexity increases
Solution Approach 1:
Multiple lens elements with different refractive powers are combined within each group to achieve aberration correction. For example, the first group combines positive refractive power elements, while the second group combines negative refractive power elements, creating compact sub-assemblies that collectively correct various aberrations without requiring excessive individual elements.
4Volume of moving object
If the lens is miniaturized for surveillance camera use, then the size is reduced, but the aberration correction becomes more difficult
Solution Approach 1:
The lens groups are arranged in a nested configuration along the optical axis, with the aperture stop positioned between the second and third groups. This nested arrangement allows compact packaging of multiple optical elements in a miniaturized form factor while maintaining the functional separation needed for aberration correction.
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 enables a compact, high-power zoom lens system suitable for surveillance cameras, effectively correcting aberrations and achieving the desired zoom ratio while maintaining a small size.
Implementation Method 1
a first group (10) having a positive refractive power, a second group (20) having a negative refractive power, a third group (30) having a positive refractive power, and a fourth group (40) having a positive refractive power arranged in this order from the object side
Data Source
AI summary
A zoom lens is provided and has a first group having a positive refractive power, a second group having a negative refractive power, an aperture stop, a third group having a positive refractive power and a fourth group having a positive refractive power, which groups are arranged in this order from the object side. The first group has a three-group four-lens configuration where a cemented lens of a negative lens and a positive lens, and two positive single-lenses and are disposed in this order from the object side. The second group has a three-group four-lens configuration where two single-lenses and each having a negative refractive power with a strong concave surface on the image side, and a cemented lens of a double-concave lens and a positive lens are disposed in this order from the object side.