Zoom Lens with Five Groups for Compact High Zoom Ratio
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Solution Overview
Problem
Modern zoom lenses face a trade-off between size reduction and maintaining high optical performance, as increasing the zoom ratio and optical performance often results in larger and heavier lenses due to the need for multiple lens groups, while fewer lens groups compromise optical quality.
Innovation Solution
A zoom lens configuration comprising specific lens groups with varying refractive powers and aspheric surfaces, allowing for a compact design while maintaining high optical performance by adjusting the positions of lens groups to switch between wide-angle and telephoto modes, thereby optimizing focal lengths and aberration control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If more lens groups are provided to raise zoom ratio and optical performance, then optical performance is improved, but the zoom lens becomes bigger and heavier
Solution Approach 1:
The zoom lens is divided into five lens groups (G1, G2, G3, G4, G5) with different refractive powers, where each group serves a specific function. The first lens group (G1) with positive refractive power includes three lenses, the second lens group (G2) with negative refractive power includes four lenses, and so on. This segmentation allows for optimized optical performance while controlling the overall size and weight by assigning specific functions to each group rather than using a uniform structure throughout.
Solution Approach 2:
Different lens groups are assigned different refractive powers and structural characteristics to optimize specific regions of the optical system. For example, the first lens group has positive refractive power with three lenses (two with positive power), while the second lens group has negative refractive power with four lenses. This local optimization of quality in different parts of the system achieves high overall performance without requiring excessive materials throughout the entire lens.
2Adaptability or versatility
If more lens groups are provided to raise zoom ratio and optical performance, then zoom ratio is improved, but the zoom lens becomes bigger and heavier
Solution Approach 1:
The zoom lens employs dynamic movement of lens groups to achieve variable focal lengths and zoom ratios. During zooming operations, the distances between lens groups are adjusted: the distance between G1 and G2 increases, while the distances between G2-G3 and G3-G4 decrease. This dynamic reconfiguration allows the lens to achieve high zoom ratios (32x or higher) without requiring a proportionally larger physical structure, as the same lens groups serve multiple focal length requirements through positional changes.
3Volume of moving object
If fewer lens groups are used to reduce size, then the zoom lens becomes smaller, but the optical performance is poor
Solution Approach 1:
The patent combines multiple optical functions into a compact five-group structure. The first lens group (G1) with positive refractive power and the second lens group (G2) with negative refractive power work together to achieve both wide-angle and telephoto capabilities. By merging the functions of traditional larger lens systems into these five coordinated groups with specific refractive power distributions, the design achieves high optical performance in a reduced volume compared to conventional designs with twenty or more lens groups.
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 high zoom ratio with small size and excellent optical performance across modes, with improved field curvature, distortion, chromatic aberration, and spherical aberration control, ensuring acceptable coma aberrations.
Implementation Method 1
The first lens group has positive refractive power, and includes three lenses, wherein two of the lenses have positive refractive power. The second lens group has negative refractive power... The third lens group has positive refractive power... The fourth lens group has positive refractive power... The fifth lens group has positive refractive power
Data Source
AI summary
A zoom lens includes a first lens group, a second lens group, an aperture, a third lens group, a fourth lens group, a fifth lens group, and an image surface in order along an optical axis from an object side to an image side. The first lens group has positive refractive power, and includes three lenses. The second lens group has negative refractive power, and includes fourth lenses. The third lens group has positive refractive power, and includes two lenses. The fourth lens group has positive refractive power, and includes five lenses. The fifth lens group has positive refractive power, and includes two lenses. Therefore, the zoom lens has a small size and high zoom ratio.