Imaging Lens Aberration Correction via Sixth Lens Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing image pickup lenses face limitations in making the back focus shorter, which restricts the arrangement of the sixth lens close to the image plane, thereby limiting the correction of various aberrations and the overall optical length.
Innovation Solution
An image pickup lens configuration with specific refractive powers and surface shapes for each lens, including a first lens with positive refractive power, a sixth lens with negative refractive power and an optically planar image plane-side surface, and intermediate lenses with aspheric surfaces, optimized by conditional expressions to achieve shorter optical overall length and improved aberration correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the sixth lens is arranged close to the image plane to correct aberrations and shorten optical length, then the back focus becomes excessively short, limiting further optimization
Solution Approach 1:
The patent applies parameter changes by modifying the refractive index and dispersion characteristics of the sixth lens. Specifically, it sets the refractive index nd6 between 1.70-1.90 and the Abbe number vd6 between 18-35, which allows the lens to achieve effective aberration correction with a shorter back focus distance, thereby resolving the contradiction between compactness and adjustment flexibility
Solution Approach 2:
The patent introduces a movable sixth lens that can shift along the optical axis. This dynamic capability allows the lens to adjust its position to optimize both the back focus distance and aberration correction performance, enabling the system to adapt between different operational requirements for compactness and adjustment range
2Manufacturing precision
If the sixth lens is positioned closer to the image plane, then aberration correction improves, but the design flexibility for back focus is reduced
Solution Approach 1:
The patent changes the optical parameters of the sixth lens, specifically setting the refractive index nd6 between 1.70-1.90 and the Abbe number vd6 between 18-35. These parameter changes enable the lens to maintain high aberration correction accuracy while allowing for greater back focus design flexibility
Solution Approach 2:
By making the sixth lens movable along the optical axis, the patent enables dynamic adjustment that maintains high aberration correction accuracy across different back focus configurations, thereby improving both manufacturing precision and design adaptability
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 effectively corrects various aberrations and reduces the optical overall length, enabling a more compact image pickup lens design while maintaining telephotographic characteristics.
Implementation Method 1
at least one of an object-side surface and an image plane-side surface of each of the second lens, the third lens, the fourth lens, and the fifth lens being an aspheric surface
Implementation Method 2
the sixth lens capable of more effectively correcting various aberrations
Data Source
AI summary
It is possible to (i) cause a sixth lens to more effectively correct various aberrations and (ii) make an optical overall length shorter. A first lens (L1) has positive refractive power. A fifth lens (L5) and a sixth lens (L6) each have negative refractive power. An object-side surface (L1F) of the first lens (L1) is a convex surface. At least one of an object-side surface and an image plane-side surface of each of a second lens (L2), a third lens (L3), a fourth lens (L4), and the fifth lens (L5) is an aspheric surface. An object-side surface (L6F) of the sixth lens (L6) is a concave surface and is an aspheric surface. An image plane-side surface (L6R) of the sixth lens (L6) is an optically planar surface throughout a region corresponding to an effective diameter of the image plane-side surface (L6R) of the sixth lens (L6).