Optical Imaging System with Folded Light Path
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Solution Overview
Problem
There is a need for an optical imaging system that achieves high resolution while being compact and slim, suitable for portable devices, as the demand for high-resolution cameras in portable terminals has increased with the miniaturization of their form factor.
Innovation Solution
The optical imaging system consists of a first lens group with positive refractive power and a second lens group with multiple lenses, including both positive and negative refractive power lenses, arranged sequentially along an optical axis, with specific focal lengths and Abbe numbers to achieve high resolution and miniaturization. The system includes a reflective member to elongate the optical path in a narrow space, allowing for a long focal length and improved chromatic aberration correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of lenses in the optical imaging system is increased to achieve high resolution, then the imaging quality is improved, but the overall length and complexity of the system increase
Solution Approach 1:
The patent introduces a reflective member (mirror) to fold the optical path, transforming a linear arrangement into a multi-dimensional configuration. This allows the optical path length to be extended without increasing the overall system length along the optical axis, effectively resolving the contradiction between high resolution (requiring long focal length) and compact size.
Solution Approach 2:
The patent arranges lenses with different refractive powers (positive and negative) in a nested configuration where the second lens group with negative refractive power is positioned between the object and the first lens group with positive refractive power. This nesting allows multiple optical functions to be achieved within a compact space, reducing the overall system length while maintaining imaging quality.
2Measurement precision
If the focal length is increased to achieve high resolution, then the imaging quality is improved, but the device size increases
Solution Approach 1:
The reflective member folds the optical path in a direction perpendicular to the optical axis, allowing the focal length to be extended without increasing the device volume in the optical axis direction. This enables high resolution imaging while maintaining a compact device form factor suitable for portable terminals.
3Measurement precision
If chromatic aberration correction is improved by adding more lenses, then the imaging quality is improved, but the device complexity and size increase
Solution Approach 1:
The patent assigns specific optical properties to different lens groups: the first lens group has positive refractive power while the second lens group has negative refractive power. This local differentiation of optical properties allows chromatic aberration correction to be achieved through the coordinated action of these specialized groups rather than requiring every lens to contribute to all correction functions, thereby reducing overall system complexity.
Solution Approach 2:
The patent uses lenses made of different materials with different Abbe numbers (dispersion characteristics) in the first and second lens groups. This composite approach, combining materials with different optical properties, enables effective chromatic aberration correction through the complementary actions of the lens groups without requiring an excessive number of elements.
4Measurement precision
If the effective diameter of the first lens is increased to reduce distortion, then the imaging quality is improved, but the device size increases
Solution Approach 1:
The patent optimizes the ratio between the effective diameter of the first lens and the focal length (expressed as the condition 0.5 < TTL/f ≤ 1.5) to achieve effective distortion control without requiring an excessively large lens diameter. This parameter optimization allows distortion correction while maintaining a compact device size.
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 achieve high resolution and miniaturization, suitable for portable devices, while maintaining a long focal length and effective chromatic aberration correction, thus addressing the challenge of integrating high-resolution imaging in a compact form.
Implementation Method 1
The optical imaging system includes a reflective member to elongate the optical path in a narrow space
Implementation Method 2
the first lens group has positive refractive power, and the second lens group has positive refractive power as a whole
Data Source
AI summary
An optical imaging system is provided. The optical imaging system includes a first lens group, a reflective member, and a second lens group arranged sequentially along an optical axis, and the first lens group may include one lens, and the second lens group includes two or more lenses, the first lens group may have positive refractive power, and the second lens group may have positive refractive power as a whole, an effective diameter of the lens included in the first lens group may be greater than an effective diameter of the lenses included in the second lens group, and 0<D1/f<0.05 may be satisfied. Here, D1 is a distance on the optical axis between an image-side surface of the lens included in the first lens group and the reflective member, and f is a total focal length of the optical imaging system.