Folded Optical Imaging System with Prisms for Compact Telephoto Design
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Solution Overview
Problem
There is a need for an optical imaging system that combines ultra-thin design, large focal length, and ultra-low distortion to meet the miniaturization and imaging requirements of consumer electronic devices like mobile phones, while maintaining high imaging quality.
Innovation Solution
The optical imaging system consists of three imaging lens groups with specific refractive power distributions and surface types, including prisms, aspheric surfaces, and carefully configured lens thicknesses and spacing, which deflect light through 90-degree angles to reduce size and minimize distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If a telephoto lens with relatively long structure size is used, then the focal length is increased, but the device size increases and miniaturization requirement cannot be met
Solution Approach 1:
The patent employs a folded optical path design where light is deflected through 90-degree angles by refraction optical elements (prisms). This transforms the linear optical path into a three-dimensional folded structure, allowing the optical system to achieve a long effective focal length while maintaining a compact physical footprint. The optical axis is folded multiple times to fit within a small form factor suitable for mobile phones.
Solution Approach 2:
The patent implements a nested arrangement where multiple lens groups are positioned along the folded optical path in a compact configuration. The lens groups are nested within each other along the optical axis, with each group contributing to the overall focal length while occupying minimal space. This allows the system to achieve telephoto functionality within a constrained volume.
2Length of moving object
If the optical system is miniaturized, then the device size is reduced, but imaging quality and distortion control become difficult to maintain
Solution Approach 1:
The patent divides the optical system into multiple discrete lens groups (first, second, and third lens groups) with specific refractive power distributions. Each lens group contains one or more lenses with carefully designed surface curvatures and thicknesses. This segmentation allows for precise control of optical aberrations and distortion while maintaining a compact overall structure, as each group can be optimized independently for its specific function.
Solution Approach 2:
The patent applies local quality by assigning different refractive powers and surface characteristics to different lens groups. The first lens group has positive refractive power, the second has negative refractive power, and the third has positive refractive power. Each lens within these groups has specifically designed curvature radii and thicknesses to correct local optical aberrations and control distortion, ensuring high imaging quality despite the miniaturized form factor.
3Length of moving object
If refraction optical elements are used to deflect light, then the device size is reduced through compact folding, but the device complexity increases
Solution Approach 1:
The refraction optical elements (prisms) serve multiple functions: they deflect light by 90-degree angles to fold the optical path, and simultaneously contribute to the overall refractive power of the system. The lens groups not only focus light but also correct optical aberrations and control distortion. This multi-functionality reduces the need for additional separate components, thereby managing complexity while achieving compact 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 achieves a compact size with high focal length and ultra-low distortion, enhancing imaging quality and reducing aberrations, thereby meeting the miniaturization and performance demands of portable electronic devices.
Implementation Method 1
a first refraction optical element configured to deflect light entering along a direction of the first optical axis to be propagated along a direction of the second optical axis
Implementation Method 2
a second refraction optical element configured to deflect light entering along the direction of the second optical axis to be propagated along a direction of the third optical axis
Implementation Method 3
a second imaging lens group, sequentially including from an object side to an image side along the second optical axis: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens with refractive power respectively
Data Source
AI summary
The disclosure provides an optical imaging system, which has a first optical axis, a second optical axis perpendicular to the first optical axis and a third optical axis perpendicular to the second optical axis, the first optical axis is parallel to the third optical axis, the optical imaging system includes: a first imaging lens group, including a first refraction optical element that deflects light entering along a direction of the first optical axis to be propagated along a direction of the second optical axis; a second imaging lens group, sequentially including from an object side to an image side along the second optical axis a first lens to a seventh lens with refractive power; a third imaging lens group, including a second refraction optical element that deflects light entering along the direction of the second optical axis to be propagated along a direction of the third optical axis.