Compact Telescopic Optical Imaging System with Movable Lens Groups
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Solution Overview
Problem
Existing telescopic optical imaging systems are too large to be effectively mounted in small electronic devices such as mobile communications terminals, due to their significant size relative to their focal length.
Innovation Solution
The optical imaging system comprises a first lens group with a positive refractive power and a second lens group with convex surfaces closest to the imaging plane, designed to satisfy specific conditional expressions for the total length to focal length ratio, lens distances, and refractive indices, allowing for a compact configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a telescopic optical system is designed to capture images at long distance, then the focal length increases, but the total length becomes significantly large (TL/f ≥ 1)
Solution Approach 1:
The optical system is divided into multiple lens groups (first lens group with positive refractive power, second lens group with negative refractive power, and third lens group) that can be independently positioned. This segmentation allows the system to achieve telescopic functionality through relative movement of lens groups rather than requiring a single long optical path, thereby reducing the total length while maintaining long-distance image capture capability.
Solution Approach 2:
The patent employs movable lens groups that can adjust their positions relative to each other along the optical axis. By dynamically changing the distances between lens groups during operation, the system can switch between different focal lengths and magnification levels, enabling long-distance imaging without requiring a permanently extended optical path.
2Length of moving object
If the total length to focal length ratio (TL/f) is reduced below 1 for compactness, then the system becomes suitable for mobile devices, but traditional telescopic optical designs cannot achieve long distance image capture
Solution Approach 1:
The patent utilizes conditional expressions that define specific ranges for parameters including TL/f < 1, refractive powers of lens groups, and distances between lenses. By optimizing these parameters within defined ranges, the system achieves compact dimensions while maintaining the optical performance necessary for long-distance imaging through the coordinated arrangement of positive and negative refractive power lens groups.
3Length of moving object
If multiple lenses with specific refractive powers are arranged in sequence, then compactness is achieved, but the optical design becomes complex
Solution Approach 1:
The patent designs lens groups that serve multiple functions: the first lens group with positive refractive power provides both convergence of light rays and contributes to the overall focal length, while the second lens group with negative refractive power simultaneously diverges rays and enables focal length adjustment through positional changes. This multi-functionality reduces the need for additional dedicated components, simplifying the overall system despite the multi-element construction.
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 optical imaging system to capture images at long distances while being compact enough to be integrated into small electronic devices, such as mobile communications terminals, without compromising image quality.
Implementation Method 1
a first lens group 1G having a first group of lenses, wherein a foremost lens of the first group of lenses is a lens closest to an object side and comprises a positive refractive power
Implementation Method 2
a second lens group 2G having a second group of lenses, wherein a rearmost lens of the second group of lenses is a lens closest to an imaging plane and comprises convex surfaces
Data Source
AI summary
An optical imaging system includes a first lens group having a first group of lenses. A foremost lens of the first group of lenses is a lens closest to an object side and has a positive refractive power. The optical imaging system also includes a second lens group having a second group of lenses. A rearmost lens of the second group of lenses is a lens closest to an imaging plane and has convex surfaces. The first and second lens groups are sequentially disposed from the object side to an imaging plane. An expression TL/f1<2.0 is satisfied, where TL represents a distance from an object-side surface of the foremost lens to the imaging plane and f1 represents a focal length of the foremost lens.