Telephoto Optical Imaging System With Folded Light Path
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Solution Overview
Problem
Current portable electronic device camera systems face challenges in achieving high image quality and ultra-long focal length while maintaining a compact and miniaturized structure due to the limitations of optical imaging system size and complexity.
Innovation Solution
A telephoto optical imaging system comprising a first lens with positive refractive power, a second lens with negative refractive power, an optical path turning prism, and a triangular prism, which folds the light path to reduce system size and energy loss, allowing for ultra-long focal length and high image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the optical imaging system uses more lenses to improve image quality and focal length, then the imaging performance is improved, but the system size and structural complexity increase
Solution Approach 1:
The patent applies aspheric surface parameters to lens surfaces, changing the geometric parameters from traditional spherical to aspheric configurations. This allows achieving superior image quality with fewer lens elements by optimizing surface curvature parameters, thereby reducing system complexity while maintaining high imaging performance
Solution Approach 2:
The patent introduces different aspheric coefficients (K values and higher-order terms) at different zones of the lens surfaces. By optimizing local surface properties rather than uniform spherical surfaces, the system achieves high image quality with reduced number of elements, resolving the contradiction between image quality and system complexity
2Length of moving object
If the optical imaging system increases focal length for telephoto capability, then the magnification is improved, but the system length increases
Solution Approach 1:
The patent employs an optical path turning prism that redirects the optical path at approximately right angles. This transforms the optical system from a linear elongated structure to a compact folded configuration, achieving ultra-long effective focal length (50mm or more) while keeping the physical system length suitable for portable devices
Solution Approach 2:
The optical path turning prism is integrated within the lens barrel structure, with the prism nested among the lens elements. This nested configuration allows the folded optical path to be contained within a compact form factor, achieving long focal length without proportionally increasing system length
3Volume of moving object
If the optical imaging system reduces the number of lenses for miniaturization, then the system size is reduced, but the manufacturing complexity increases
Solution Approach 1:
The patent uses aspheric surface parameters with specific K values and higher-order coefficients that can be directly manufactured using modern precision molding or grinding techniques. By optimizing these parameters, the system achieves compact size with fewer lenses while maintaining manufacturability through standardized aspheric surface fabrication processes
Solution Approach 2:
The patent divides the optical system into functional groups (positive power lens group, negative power lens group, and optical path turning prism) rather than using many individual spherical lenses. This segmentation into fewer but more functionally optimized elements reduces system size while the aspheric parameters provide clear manufacturing specifications for each element
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-quality optical imaging system with an ultra-long focal length, meeting the requirements of miniaturization and image quality while maintaining a small system size, through the strategic configuration of refractive power, surface shape, and lens spacing.
Implementation Method 1
An imaging light incident to the optical path turning prism along the optical axis is reflected sequentially at a first optical path turning surface of the optical path turning prism and a second optical path turning surface of the optical path turning prism and emitted perpendicularly from the exit surface of the optical path turning prism
Implementation Method 2
The light perpendicularly emitted from the exit surface of the optical path turning prism is reflected at a reflecting surface of the triangular prism and deflected by 90° with a deflection direction toward the image side
Implementation Method 3
At least one of an object-side surface of the first lens to an image-side surface of the second lens is aspheric
Data Source
AI summary
A telephoto optical imaging system and zoom camera apparatus. The telephoto optical imaging system includes, sequentially from an object side to an image side along an optical axis, a first lens having positive refractive power, a second lens having negative refractive power, an optical path turning prism, and a triangular prism. Distance T from the object-side surface of the first lens to an imaging plane of the telephoto optical imaging system in a normal direction of the imaging plane and the total effective focal length F1 of the telephoto optical imaging system satisfy T/F1<0.6. The zoom camera apparatus includes the telephoto optical imaging system and a short-focus optical imaging system arranged in parallel with the telephoto optical imaging system. A total effective focal length F1 of the telephoto optical imaging system and a total effective focal length F2 of the short-focus optical imaging system satisfy F1/F2>5.