Folded Optical Imaging Layout for Compact Long-Focal Modules
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Solution Overview
Problem
The challenge of miniaturizing retractable optical imaging systems with multiple lenses is significant, particularly when integrating them into portable terminals with limited thickness, as the overall length increases with the number of lenses, hindering their mounting in such devices.
Innovation Solution
An optical imaging system is designed with a specific configuration of lenses and a prism to fold the optical path, allowing for a compact design while maintaining a long focal length, utilizing lens groups that move along the optical axis to adjust focus and zoom, and incorporating a prism to bend the optical path at a right angle, thereby reducing the system's overall length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the number of lenses is increased to achieve a long focal length, then the focal length is improved, but the overall length of the optical imaging system increases
Solution Approach 1:
The patent introduces a folding mirror to redirect the optical path at a right angle, transforming the linear optical path into a two-dimensional configuration. This allows the optical system to achieve a long focal length while maintaining a compact overall length by utilizing spatial dimensions beyond the simple linear arrangement of lenses.
2Measurement precision
If the number of lenses is increased to achieve precise focus adjustment and zoom, then the optical performance is improved, but the system complexity and size increase
Solution Approach 1:
The patent divides the optical system into distinct lens groups (first lens group, second lens group, third lens group) with specific functions. Each group contains lenses with particular refractive power characteristics, allowing independent movement for focus adjustment and zoom operations. This segmentation enables precise control while managing system complexity through functional modularity.
Solution Approach 2:
The patent implements a retractable mechanism where lens groups can move along the optical axis to adjust focus and zoom. The system transitions from a static to a dynamic configuration, allowing the optical imaging system to adapt its parameters (focal length, focus position) by changing the relative positions of lens groups, thereby achieving precise adjustment without permanently increasing system complexity.
3Length of moving object
If the optical path is folded using a prism, then the overall length is reduced, but the manufacturing complexity increases
Solution Approach 1:
The patent introduces a folding mirror as an intermediary optical element to redirect the light path at a right angle. This mirror serves as a mediator that enables the compact folded configuration without requiring complex prism assemblies, thereby reducing manufacturing complexity while still achieving the goal of minimizing overall system length.
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 system achieves a compact, thinned design suitable for portable terminals by optimizing lens arrangements and using a prism to fold the optical path, enabling precise focus adjustment and significant zoom ratio changes with minimal displacement, thus overcoming the miniaturization limitations of traditional systems.
Implementation Method 1
incorporating a prism to bend the optical path at a right angle, thereby reducing the system's overall length
Implementation Method 2
utilizing lens groups that move along the optical axis to adjust focus and zoom
Data Source
AI summary
An optical imaging system includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens disposed sequentially from an object side. The optical imaging system satisfies −2.0<L3R2/f<−0.5 and 3.0<f/IMG_HT<4.0, where L3R2 is a radius of curvature of an image-side surface of the third lens, f is a focal length of the optical imaging system, and IMG_HT is half a diagonal length of an imaging plane.