Catadioptric Camera Lens Narrow Angle Design
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Solution Overview
Problem
Existing camera lenses with catadioptric optical systems face challenges in achieving a small height and narrow angle with good optical properties due to insufficient refractive indices and Abbe numbers, leading to a field of view angle greater than or equal to 21.4°, which is not narrow enough.
Innovation Solution
A camera lens design comprising two lens assemblies and one lens, with specific refractive index and Abbe number ratios, and curvature radius conditions, including a first lens assembly with refractive and reflective surfaces, a second lens assembly with reflective and refractive surfaces, and a third lens with refractive power, optimized to achieve a narrow angle and compact size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the peripheral region and central region of the second lens are formed into one piece with insufficient refractive index and Abbe number, then the manufacturing is simplified, but the field of view angle becomes greater than or equal to 21.4° which is not narrow enough
Solution Approach 1:
The second lens is divided into two separate lenses: a second lens with insufficient refractive index and Abbe number, and a third lens with specifically controlled refractive index (1.68≤nd3≤1.91) and Abbe number satisfying 3.50≤(ν1+ν2)/ν3≤6.00. This segmentation allows each lens to have optimized optical properties, enabling the achievement of a narrow field of view angle (less than 21.4°) while maintaining manufacturing feasibility through standardized lens production processes.
2Length of stationary object
If a camera lens with small height and narrow angle is designed, then the compactness is improved, but the optical properties deteriorate due to insufficient refractive index and Abbe number ratios
Solution Approach 1:
The patent specifies precise parameter ranges for the third lens: refractive index 1.68≤nd3≤1.91 and Abbe number satisfying 3.50≤(ν1+ν2)/ν3≤6.00. Additionally, curvature radius ratios are controlled within specific ranges: 0.70≤(|R3|+R4|)/f≤1.20 and 0.90≤(|R7|+|R8|)/f≤4.00. These parameter optimizations enable the compact lens design (small height) to achieve narrow angle (less than 21.4°) while maintaining excellent optical properties through mathematical optimization of the optical path.
3Length of moving object
If the refractive index and Abbe number ratios are optimized for narrow angle, then the field of view is reduced below 21.4°, but the device complexity increases with additional lens elements
Solution Approach 1:
The third lens is positioned specifically to correct optical aberrations in the narrow-angle regime. Its refractive index (1.68≤nd3≤1.91) and Abbe number (3.50≤(ν1+ν2)/ν3≤6.00) are locally optimized for the central field of view, while the first and second lenses handle the peripheral regions. This local quality optimization allows achieving narrow angle (less than 21.4°) without proportionally increasing overall system complexity.
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 design improves the optical path configuration, achieving a small and compact narrow-angle lens with enhanced diffraction limit and telephoto capabilities, suitable for portable cameras with high-pixel CCD or CMOS imaging elements, while maintaining good optical properties.
Implementation Method 1
a first lens assembly having a reflective power and a refractive power, wherein an object side surface of the first lens assembly includes a first refractive surface in a peripheral region thereof and a second reflective surface in a central region thereof
Implementation Method 2
a second lens assembly having a reflective power and a refractive power, wherein an object side surface of the second lens assembly includes a third refractive surface and a fourth refractive surface that are sequentially arranged from a peripheral region to a central region thereof, and an image side surface of the second lens assembly includes a first reflective surface
Implementation Method 3
a third lens having a refractive power, The camera lens satisfies following conditions: 1.68≤nd3≤1.91; and 3.50≤(ν1+ν2)/ν3≤6.00
Data Source
AI summary
Provided is a camera lens of a catadioptric optical system consisting of two lens assemblies and one lens and having a small height, a narrow angle, and good optical properties. The camera lens includes: a first lens assembly including an object side surface having a first refractive surface and a second reflective surface in a peripheral region and a central region thereof, and an image side surface having a second refractive surface, a fifth refractive surface and a sixth refractive surface that are sequentially arranged from a peripheral region to a central region thereof; a second lens assembly including an object side surface having a third refractive surface and a fourth refractive surface that are sequentially arranged from a peripheral region to a central region, and an image side surface having a first reflective surface; and a third lens having a refractive power.