Compact Compound Zoom Lens with Folded Optical Path
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current zoom lenses with high zoom ratios and wide fields of view are either complex, large, and expensive, or lack the compactness required for consumer electronics, and existing compound zoom systems do not provide a simple, economically producible solution for high-volume applications in devices like cell phones and digital cameras.
Innovation Solution
A compact, ultra-wide angle, optionally rotatable compound zoom lens design with two or three independently moving lens groups, utilizing a zooming kernel and relay with a stationary P lens group in between, allowing for athermalization and temperature compensation, and incorporating fold prisms or mirrors to maintain a small form factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional zoom lens designs are used to achieve high zoom ratios and wide fields of view, then the zoom range and field of view are improved, but the device complexity, size, and cost increase significantly
Solution Approach 1:
The optical system is divided into distinct functional groups: a stationary P lens group that remains fixed, and moving zoom groups (G1 and G2) that change position during zooming. This segmentation allows each group to be optimized for its specific function, reducing overall complexity while achieving high zoom ratios (e.g., 4.8x or 5.5x) and wide fields of view (up to 90 degrees)
Solution Approach 2:
The moving lens groups serve multiple functions simultaneously: they perform zooming by changing focal length, focusing by adjusting image plane position, and athermalization by compensating for temperature-induced focal shifts. This multi-functionality eliminates the need for separate mechanisms, reducing device complexity while maintaining versatile performance
2Adaptability or versatility
If conventional zoom lens designs are used to achieve high zoom ratios and wide fields of view, then the zoom range and field of view are improved, but the lens size increases and becomes unsuitable for compact consumer electronics
Solution Approach 1:
The patent employs fold prisms or mirrors to introduce optical path folding, effectively utilizing the third dimension (depth) to achieve a compact form factor. The optical path is folded back on itself, allowing the physical lens assembly to be much shorter than the optical path length would suggest, enabling high zoom ratios in compact devices like cell phones and PDAs
3Adaptability or versatility
If conventional zoom lens designs are used to achieve high zoom ratios and wide fields of view, then the zoom range and field of view are improved, but the manufacturing cost increases making high-volume production economically unviable
Solution Approach 1:
Multiple functions (zooming, focusing, athermalization) are merged into a single coordinated movement of the zoom groups, rather than requiring separate mechanisms for each function. This merging reduces the number of independent moving parts, simplifies the drive mechanism, and lowers manufacturing costs while achieving the desired optical performance for high-volume consumer electronics production
4Device complexity
If the number of independently moving lens groups is reduced to achieve simplicity and compactness, then device complexity and size are reduced, but maintaining wide zoom range and field of view becomes difficult
Solution Approach 1:
The patent achieves high zoom ratios with minimal moving groups by optimizing key parameters: the stationary P lens group is positioned and sized to provide a stable optical reference, the moving groups use specific focal length ratios, and the optical path folding geometry is carefully designed. These parameter optimizations allow 2-3 moving groups to achieve the same performance that would traditionally require many more elements
Data Source
Figure 1
Figure 2~4
Figure 5
AI summary
A zoom lens is disclosed having a zoom ratio larger than four with a field of view at the short focal length position larger than 85 degrees and with a minimal number of moving groups. The zoom lens utilizes a compound zoom structure comprising an NP or NPP zoom kernel followed by a P or PP zoom relay, with only two or three moving groups that can be used for both zooming, focusing and athermalization. An overall compact package size is achieved by the use of prisms to fold the optical path in strategic locations. An optional variable power liquid cell can provide close focusing with little or no focus breathing.