Three-Lens Single Focus Optical System with Aberration Correction
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Solution Overview
Problem
Current image pick-up lenses for small-sized devices like mobile phones and digital cameras face challenges in achieving compactness and high performance while maintaining a minimal number of lenses.
Innovation Solution
A single focus lens system comprising a first positive power lens, a second negative meniscus lens, and a third aspheric lens, with specific refractive index and Abbe number conditions, and an aperture stop placement to optimize focal distance, curvature radius, and aberration correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a three-lens construction is used to achieve compactness, then the number of lenses is reduced, but aberration correction performance deteriorates
Solution Approach 1:
The patent applies parameter changes by specifying precise refractive index ranges (NdB: 1.49-1.70, NdA: 1.65-2.05) and Abbe number ranges (vdB: 25-55, vdA: 15-30) for the lens materials. These parameter constraints enable optimal aberration correction within the three-lens configuration, resolving the contradiction between reduced lens count and maintained optical performance
Solution Approach 2:
The patent employs composite material selection by combining lenses with different refractive indices and dispersion characteristics. The first lens uses materials with NdB and vdB within specific ranges, while the second lens uses materials with NdA and vdA within different ranges, creating a composite optical system that achieves superior aberration correction with only three elements
2Manufacturing precision
If lens materials with high refractive index are used to reduce lens curvature, then manufacturing precision improves, but material cost and availability worsen
Solution Approach 1:
The patent optimizes the refractive index parameters to balance manufacturing precision and material availability. By specifying NdB: 1.49-1.70 and NdA: 1.65-2.05, the patent selects ranges that enable effective aberration correction without requiring exotic or difficult-to-manufacture materials, thus resolving the contradiction between precision and ease of manufacture
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 solution enables a compact, high-performance lens system with effective aberration correction and reduced length, utilizing only three lenses, while allowing for the selection of cost-effective and easily available materials like acrylic resin or cycloolefin polymer.
Implementation Method 1
a first lens of positive power having a convex-shaped surface on an object side
Implementation Method 2
a second lens of a negative meniscus lens having, on the object side, a concave-shaped surface on its paraxial axis
Implementation Method 3
νdA: Abbe number of the second lens, νdB: Abbe number of the first lens and the third lens
Implementation Method 4
a third lens of an aspheric lens having, on the object side, a convex-shaped surface on its paraxial axis
Data Source
AI summary
A single focus lens comprises: a first lens of positive power having a convex-shaped surface on an object side; a second lens of a negative meniscus lens having, on the object side, a concave-shaped surface on its paraxial axis; and a third lens of an aspheric lens having, on the object side, a convex-shaped surface on its paraxial axis, in this order from the object side, wherein the single focus lens satisfies the predetermined conditions.