Inverted Lens Group for Wide-Angle Imaging
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Solution Overview
Problem
Existing imaging lenses for in-vehicle applications face challenges in achieving a balance between high imaging performance, wide angle of view, low F-number, and miniaturization, with limitations in brightness, distortion correction, and durability under varying environmental conditions.
Innovation Solution
The imaging lens configuration includes a negative meniscus lens, a positive meniscus lens, and additional lenses with specific refractive powers and surface shapes, along with an aperture stop placement, to achieve a wide angle of view, low F-number, and compact size, while using glass lenses for thermal stability and suppressing aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a lens group having positive combined refractive power is configured by a lens disposed closer to the object than the aperture stop, then low distortion is realized while having a relatively wide angle, but the imaging lens cannot secure a sufficient aperture stop diameter and the brightness is insufficient
Solution Approach 1:
The lens is divided into multiple lens groups with different refractive powers arranged in specific sequences. The object-side lens group has negative refractive power while the image-side lens group has positive refractive power, allowing each group to independently optimize for its function (distortion control vs. brightness) without compromising the other.
Solution Approach 2:
Instead of placing the positive refractive power lens closer to the object (as in conventional designs), this invention inverts the arrangement by placing the negative refractive power lens closer to the object and the positive refractive power lens closer to the image, thereby achieving both wide angle/low distortion and sufficient brightness simultaneously.
2Illumination intensity
If the F number is reduced to increase brightness, then sufficient visibility under low illuminance is achieved, but the lens diameter increases and miniaturization is compromised
Solution Approach 1:
The invention changes the refractive power parameters of the lens groups, specifically making the object-side lens group have negative refractive power and the image-side lens group have positive refractive power. This parameter inversion allows the system to achieve high brightness (low F number) while maintaining a compact form factor.
Solution Approach 2:
The lens system uses composite optical design combining multiple lens materials with different refractive indices and aberration characteristics. This allows optimization of light gathering efficiency while controlling the physical dimensions of each lens element, achieving bright imaging with miniaturization.
3Area of stationary object
If the angle of view is widened for in-vehicle sensing, then the imaging range is increased, but the imaging performance and distortion correction become more difficult to maintain
Solution Approach 1:
The lens is segmented into multiple lens groups that can independently correct aberrations. The object-side negative lens group handles wide-angle light rays while the image-side positive lens group corrects distortion and maintains sharpness, allowing wide imaging range without sacrificing image quality.
Solution Approach 2:
Different regions of the lens system are optimized for different functions: the object-side lens group is optimized for wide-angle acceptance and distortion control, while the image-side lens group is optimized for focus sharpness and aberration correction. This local optimization allows simultaneous achievement of wide angle of view and high imaging performance.
4Reliability
If glass lenses are used for thermal stability, then durability under varying environmental conditions is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The invention specifies precise parameter ranges for the glass lenses including refractive power, curvature radii, and thickness ratios (e.g., Expression 1: 1.0 < D2/f < 3.0). These controlled parameters simplify the manufacturing process by providing clear design targets while maintaining the thermal stability benefits of glass materials.
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 results in an imaging lens that is bright, has a wide imaging range, and maintains high imaging performance while being miniaturized, suitable for in-vehicle applications with improved durability and reduced sensitivity to environmental changes.
Implementation Method 1
an imaging lens includes, in order from an object side to an image side, a first lens G1 including a negative meniscus lens having a convex shape facing the object, a second lens G2 including a positive meniscus lens having a convex shape facing the image
Data Source
AI summary
An imaging lens includes, in order from an object side to an image side, a first lens including a negative meniscus lens having a convex shape facing the object, a second lens including a positive meniscus lens having a convex shape facing the image, at least one lens including a third lens, a fourth lens, a fifth lens, and a sixth lens including a positive lens having a convex image side surface, and Expression (1) is satisfied as follows. Further, an imaging apparatus including the imaging lens is provided.1.2<D2/f  (1)whereD2 is a thickness of the second lens on the optical axis, andf is a focal length of the imaging lens.