Six-Element Camera Optical Lens for Visible-Infrared Wide-Angle Imaging
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Solution Overview
Problem
Existing camera optical lenses for in-vehicle laser radars fail to meet the requirements of large aperture, ultra-wide angle, and wide working bands, particularly in varying environmental conditions.
Innovation Solution
A camera optical lens design comprising a sequence of lenses with specific refractive powers, curvature radii, and refractive indices, including a first lens with negative power, a second lens with convex and concave surfaces, and a third lens made of glass, satisfying conditions such as −1.70≤f1/f≤−1.40, 0.11≤BF/TTL≤0.17, and nd3≥1.70, to achieve large aperture and ultra-wide angle, covering visible and infrared light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If a conventional camera optical lens is used, then the structure is simple, but it cannot meet the requirements of large aperture and ultra-wide angle
Solution Approach 1:
The optical system is divided into six separate lens elements with different refractive powers and characteristics. Each lens is optimized for specific functions: the first lens provides negative refractive power for wide angle, the second lens corrects aberrations, the third lens handles infrared transmission, and the remaining lenses balance the optical path. This segmentation allows each component to be simpler while the collective system achieves complex performance requirements.
Solution Approach 2:
The patent employs composite optical design by combining lenses with different material properties and refractive indices. Specifically, the third lens uses glass material with refractive index nd3≥1.70 for infrared transmission, while other lenses use materials optimized for visible light. This composite approach enables the system to handle both visible and infrared wavelengths simultaneously, achieving large aperture and ultra-wide angle capabilities.
2Adaptability or versatility
If the working band is extended to cover visible and infrared light, then day and night confocality is achieved, but the lens design complexity increases
Solution Approach 1:
The optical system is designed to perform multiple functions across different wavelength ranges. The same lens assembly handles visible light imaging during day and infrared light detection during night, eliminating the need for separate optical systems. The sixth lens specifically transmits infrared light while the overall configuration maintains visible light performance, achieving universal applicability across day and night conditions.
Solution Approach 2:
The patent achieves broad spectral coverage by carefully selecting and optimizing the refractive index parameters of each lens. The third lens has refractive index nd3≥1.70, which is specifically optimized for infrared transmission. The curvature radii and thicknesses of all lenses are adjusted to ensure proper optical performance across both visible and infrared bands, allowing the system to adapt to different working conditions without changing the physical structure.
3Measurement precision
If the aperture is enlarged to improve detection capability, then the optical performance improves, but the back focal length requirements become more stringent
Solution Approach 1:
The optical system uses the movable sixth lens to dynamically adjust the optical path and focus. The sixth lens is positioned at a specific distance from the image sensor and can be adjusted to optimize the back focal length while maintaining large aperture performance. This dynamic adjustment allows the system to achieve both improved optical precision and satisfied back focal length requirements.
Solution Approach 2:
The sixth lens serves as an intermediary element between the fifth lens and the image sensor. It is specifically designed with positive refractive power to transmit infrared light while also contributing to the overall focus adjustment. This intermediary lens allows the system to maintain a manageable back focal length while achieving the desired aperture size for improved detection precision.
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 lens design provides good optical performance with large aperture and ultra-wide angle, enabling day and night confocality for in-vehicle laser radars by covering both visible and infrared light.
Implementation Method 1
a first lens having a negative refractive power, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens... nd3 represents a refractive index of the third lens
Data Source
AI summary
A camera optical lens includes in sequence from an object side to an image side: a first lens having a negative refractive power, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens. The camera optical lens satisfies the following conditions: −1.70≤f1/f≤−1.40; 0.11<BF/TTL≤0.17; 2.90≤(R3+R4)/(R3−R4)≤50; and nd3≥1.70, where f, TTL and BF represent a focal length, a total track length and a back focus length of the camera optical lens respectively; f1 represents a focal length of the first lens; R3 and R4 represent curvature radius of an object-side surface and an image-side surface of the second lens respectively; and nd3 represents a refractive index of the third lens. The camera optical lens has good optical performance, and can meet the design requirements of large aperture and ultra-wide angle, and the working band of the camera optical lens can cover visible and infrared light.