Four-Lens Optical Imaging Layout for Low-Light Miniaturization
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Solution Overview
Problem
Optical systems in small terminals face challenges in achieving low F numbers and high-resolution imaging, especially in low-illuminance environments.
Innovation Solution
An optical imaging system comprising four lenses with specific refractive powers and configurations, including a first lens with low visible light transmission and high infrared transmission, and a fourth lens with a concave image-side surface, to achieve an F number equal to or less than 1.0 and enable high-resolution imaging in low-light conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the total length of the optical system is shortened to fit in a small terminal, then the device size is reduced, but the ability to achieve low F number and high-resolution imaging deteriorates
Solution Approach 1:
The optical system is divided into four distinct lens groups (first lens group, second lens group, third lens group, fourth lens group) with specific refractive power configurations. Each group contributes differently to light convergence and aberration correction, enabling compact design while maintaining imaging quality. The segmentation of optical functions across multiple groups allows achieving low F number (≤1.0) in a shortened total length.
Solution Approach 2:
Different lens groups have specifically optimized local properties: the first lens group has positive refractive power with specific curvature characteristics, the second lens group has negative refractive power for divergence control, the third lens group has positive refractive power with asymmetric surface designs, and the fourth lens group has negative refractive power. This local optimization of optical properties in different segments enables high-resolution imaging despite compact overall dimensions.
2Illumination intensity
If the F number is reduced to enable low-illuminance imaging, then the light gathering ability is improved, but the optical system complexity increases
Solution Approach 1:
The patent achieves F number ≤1.0 by precisely controlling key parameters including the refractive powers of each lens group, the axial distances between groups, and the curvature radii of lens surfaces. Specific parameter relationships are established (e.g., the fourth lens group has negative refractive power with specific curvature characteristics) to optimize light gathering while managing system complexity through mathematical constraints on these parameters.
Solution Approach 2:
The optical system uses a composite structure of four lens groups with different refractive power characteristics and material properties. Each lens group is designed with specific refractive indices and Abbe numbers to control chromatic aberration and spherical aberration. This composite optical design enables low F number imaging by combining the optical effects of multiple lens groups with complementary properties.
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 enables high-resolution imaging in low-illuminance environments while maintaining a compact size, achieving an F number of 1.0 or less and satisfying various focal length and curvature radius conditions.
Implementation Method 1
Visible light transmission of the first lens may be equal to or less than 5%
Implementation Method 2
a first lens having positive refractive power, a second lens having positive refractive power, a third lens having positive refractive power, and a fourth lens having positive refractive power
Data Source
AI summary
An optical imaging system includes a first lens having positive refractive power, a second lens having positive refractive power, a third lens having positive refractive power, and a fourth lens having positive refractive power, and an F No. of the optical imaging system is equal to or less than 1.0. The optical imaging system is capable of achieving miniaturization while capturing an image at low illumination.