Zoom Lens System with Fixed Intermediate Image Formation
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Solution Overview
Problem
Wide-angle zoom lens systems face challenges in achieving a compact design while maintaining sharp images and preventing fluctuations in the intermediate image position during zooming, which can lead to issues like scratches and dust contamination in the final image.
Innovation Solution
A zoom lens system comprising a fixed first optical system forming an intermediate image and a moving second optical system, with a first negative meniscus lens and a third fixed lens group, where the first optical system remains stationary during zooming, ensuring the intermediate image position is fixed, and the second optical system includes variator lens groups to adjust magnification, allowing for a compact and wide-angle design with reduced overall length and simplified zooming mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the first optical system is made movable to enable zooming, then zooming functionality is achieved, but the intermediate image position fluctuates causing scratches and dust contamination in the final image
Solution Approach 1:
The optical system is divided into two independent segments: the first optical system (fixed lens groups G1 and G2) that forms the intermediate image, and the second optical system (movable lens groups G3 and G4) that performs zooming. By separating these functions into distinct segments, the intermediate image position remains stable while zooming functionality is achieved through the movable second optical system.
2Adaptability or versatility
If the lens system is designed to be more wide-angle, then the field of view is increased, but the overall length of the lens system increases
Solution Approach 1:
The lens groups are arranged in a nested configuration where the fixed lens groups G1 and G2 form a compact first optical system, and the movable lens groups G3 and G4 are positioned to overlap partially with the first optical system's light path. This nesting allows the wide-angle first optical system to be integrated with the zooming second optical system without significantly increasing the overall length.
3Adaptability or versatility
If the lens aperture of the first negative meniscus lens is increased to make the system more wide-angle, then the field of view is increased, but the lens size and complexity increase
Solution Approach 1:
The first negative meniscus lens G11 is designed with specific local optical properties (negative refractive power and meniscus shape) that are optimized for wide-angle performance. Rather than uniformly increasing all lens apertures, the invention applies the meniscus lens configuration specifically where needed to achieve wide-angle capability while maintaining compact overall dimensions and managing complexity.
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
This configuration enables the creation of a compact, wide-angle zoom lens system that maintains a stable intermediate image position, suppresses aberrations, and effectively corrects chromatic aberration, resulting in sharp final images across the zoom range without lens surface contamination.
Implementation Method 1
a first negative meniscus lens that is disposed closest to the object side and whose convex surface is oriented toward the object side... This lens group guides the light flux that has passed the first meniscus lens across the opposite side to the optical axis and forms an inverted image as an intermediate image
Implementation Method 2
the second optical system includes a variator lens group that moves during zooming... the variator lens group included in the second optical system moves but the wide-angle and fixed lens group of the first optical system does not move
Implementation Method 3
the fixed lens group includes a first negative meniscus lens... Since the first optical system that forms the intermediate image is fixed, it is possible to also fix the formation position (imaging position) of the intermediate image
Implementation Method 4
the second fixed lens group to include a first cemented lens disposed closest to the object side and for the first cemented lens to include a biconvex positive lens and a biconcave negative lens disposed in order from the object side... By disposing the first cemented lens on the final image side to the entrance pupil, it is possible to effectively correct chromatic aberration
Data Source
Figure 1(a)~1(b)
Figure 2
Figure 3(a)~3(c)
AI summary
A zoom lens system (10) includes: a primary image forming lens group (11) that forms light from an object side (10a) into an intermediate image (51) and a relay lens group (12) that forms light from the intermediate image (51) into a final image (52), wherein the primary image forming lens group (11) includes, in order from the object side (10a), a first fixed lens group (G1) with negative refractive power, a stop (St), and a second fixed lens group (G2) with positive refractive power, and the relay lens group (12) includes, in order from the object side (10a), a third fixed lens group (G3) with negative refractive power, a first moving lens group (G4) with positive refractive power, and a second moving lens group (G5) with positive refractive power.