Aspherical Projection Lens Aberration Correction
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Solution Overview
Problem
The demand for smaller projection lenses with high optical performance has increased due to the development of smaller and lighter projector devices, including those with integrated projector functions in digital cameras and portable telephones, while existing lenses struggle to effectively correct various aberrations in compact optical systems.
Innovation Solution
A projection lens configuration comprising a first biconvex lens component with positive refractive power, a second meniscus lens component with negative refractive power, and a third lens component with a convex surface facing the projection side, where lens surfaces are aspherical, and specific conditional expressions are satisfied to optimize focal lengths, radii of curvature, Abbe numbers, and refractive indices, ensuring ideal aberration correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the projection lens is downsized to meet demand for smaller projector devices, then the size and weight of the optical system are reduced, but the ability to effectively correct various aberrations deteriorates
Solution Approach 1:
The patent applies aspherical surfaces to multiple lens components (first lens component L1, second lens component L2, and third lens component L3) to correct aberrations in the compact optical system. The aspherical shapes enable effective aberration correction despite the reduced size and number of lens elements, resolving the contradiction between downsizing and maintaining optical performance.
Solution Approach 2:
The patent optimizes specific parameter ranges including the focal length ratio (0.2 < f/(−f2) < 1.0), refractive indices (1.45 < nd1 < 1.55, 1.50 < nd2 < 1.64), and Abbe numbers (50 < νd1 < 60, 20 < νd2 < 30) to achieve ideal aberration correction in the compact projection lens system.
2Device complexity
If the number of lens components is reduced to downsize the projection lens, then the complexity and size of the optical system are reduced, but the ability to correct chromatic and curvature of field aberrations deteriorates
Solution Approach 1:
The patent divides the optical system into three functional lens components: a first biconvex lens component (L1) for positive refractive power, a second meniscus lens component (L2) for negative refractive power to correct chromatic aberration, and a third lens component (L3) with a convex surface facing the projection side. This segmentation enables effective aberration correction with a minimal number of elements.
Solution Approach 2:
The patent combines lens components made from materials with different refractive indices and Abbe numbers to achieve chromatic aberration correction. Specifically, the first lens component uses material with 1.45 < nd1 < 1.55 and 50 < νd1 < 60, while the second lens component uses material with 1.50 < nd2 < 1.64 and 20 < νd2 < 30, creating a composite optical system that corrects aberrations effectively.
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 achieves ideal correction of various aberrations, including chromatic and curvature of field aberrations, while maintaining a small and short optical system, thereby ensuring high optical performance and image quality.
Implementation Method 1
a first lens component (L1) which has positive refractive power and is biconvex; a second lens component (L2) which has negative refractive power and is meniscus; and a third lens component (L3) which has positive refractive power
Data Source
AI summary
A projection lens PL comprises, in order from a projection side: a first lens component L1 which has positive refractive power and is biconvex; a second lens component L2 which has negative refractive power and is meniscus; and a third lens component L3 which has positive refractive power and has a convex lens surface facing the projection side, lens surfaces on the projection side and an object side of the first lens component L1 and lens surfaces on the projection side and the object side of the second lens component L2 being aspherical, and the following conditional expression being satisfied:0.2<f/(−f2)<0.7where f2 denotes a focal length of the second lens component, and f denotes a focal length of the projection lens.