Negative-Power Front Lens Layout for Compact Wide-Angle Imaging
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Solution Overview
Problem
Existing imaging optical systems for in-vehicle and surveillance cameras face challenges in downsizing the first lens while maintaining optical characteristics.
Innovation Solution
The imaging optical system is configured with specific conditional expressions to downsize the first lens, ensuring negative power and correcting various aberrations, using a combination of lenses made of different materials to improve temperature characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the first lens is downsized to reduce the overall system size and improve user perception, then the lens diameter decreases, but optical characteristics deteriorate
Solution Approach 1:
The patent applies parameter changes by optimizing the conditional expressions for the first lens's effective radius, curvature radii, and focal length relationships. Specifically, it sets precise ranges for sd11/IH (effective radius to image height ratio), R11/f0 (object-side curvature radius to focal length ratio), and R12/f0 (image-side curvature radius to focal length ratio), allowing the first lens to be downsized while maintaining optical performance through mathematically optimized geometric parameters
Solution Approach 2:
The patent uses composite materials by combining the first lens with subsequent lens groups that have different optical properties. The first lens with negative power is integrated with following positive and negative power lenses, creating a composite optical system where each lens group compensates for the limitations of others, enabling the first lens to be smaller while the overall system maintains required optical characteristics
2Volume of moving object
If the first lens is downsized, then the imaging optical system becomes more compact, but brightness and field of view are reduced
Solution Approach 1:
The patent optimizes the parameter sd11/IH (effective radius of first lens to maximum image height ratio) within a specific range to balance lens size and brightness. By precisely controlling this ratio along with other parameters, the system achieves compact size while maintaining adequate illumination intensity across the image field
Solution Approach 2:
The patent segments the optical system into multiple lens groups (first lens group, second lens group, etc.) with different functions. The first lens group handles initial light gathering with optimized negative power, while subsequent groups compensate for brightness and field of view, allowing the first lens to be downsized without sacrificing overall system brightness performance
3Volume of moving object
If the first lens is downsized, then the system is more compact, but aberration correction becomes more difficult
Solution Approach 1:
The patent applies parameter changes by establishing specific conditional expressions for curvature radii (R11/f0, R12/f0) and their relationships. These optimized parameters enable the first lens to be downsized while maintaining the geometric conditions necessary for aberration correction, effectively translating optical theory into practical design guidelines for compact systems
Solution Approach 2:
The patent uses a composite lens structure where the first lens (with negative power) is combined with subsequent lens groups having different power characteristics. This composite arrangement allows the first lens to be smaller while the combined system maintains proper aberration correction through the complementary optical properties of different lens groups
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 achieves downsized first lens dimensions while maintaining optical performance and correcting aberrations, ensuring adequate brightness and wide field of view.
Implementation Method 1
the first lens has a negative power
Data Source
AI summary
An imaging optical system includes: in order from an object side to an image side, a front group; a diaphragm; and a rear group. The front group includes a plurality of lenses including a first lens arranged closest to the object side. The rear group includes a plurality of lenses. The first lens has a negative power. When a total track of an entire lens system is d0, an effective radius of a lens surface of the first lens on the object side is sd11, and a maximum image height is IH, the following conditional expressions:3.< d0/sd11<4.5(1)2.5<d0/IH<5.000(2)are satisfied.