Projection Lens Aberration Correction via ABBE Ratio Optimization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional short throw projection lenses with ultra-short focal lengths require expensive aspherical lenses to eliminate lateral color aberration, increasing manufacturing costs.
Innovation Solution
A projection lens design comprising a first lens group with a negative diopter adjacent to the screen and a second lens group with a positive diopter, including a negative biconcave lens and three positive lenses, where the ABBE number ratio and refractive index are optimized to correct image distortion and eliminate lateral color aberration, using a fifth aspherical lens to reduce manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an aspherical lens is used to eliminate lateral color aberration in conventional short throw projection lenses, then lateral color aberration is eliminated, but manufacturing cost greatly increases
Solution Approach 1:
The patent changes the optical parameters by using multiple lenses with specific refractive indices and ABBE numbers instead of a single aspherical lens. The first lens has refractive index ≤1.64 and ABBE number Vd1, while the second lens has refractive index >1.64 and ABBE number Vd2, with the ratio 0.4≤Vd2/Vd1≤1.2. This parameter optimization eliminates lateral color aberration through careful selection of glass materials and lens configurations, avoiding the need for expensive aspherical lenses.
2Device complexity
If a conventional two-lens-group design is used for short throw projection, then the lens structure is simple, but lateral color aberration cannot be eliminated
Solution Approach 1:
The patent segments the lens system into three distinct lens groups: a first lens group with a first lens (refractive index ≤1.64), a second lens group with a second lens (refractive index >1.64), and a third lens group with additional lenses. Each group is positioned at specific distances from the imaging unit and screen. This segmentation allows each lens group to perform specific functions while collectively eliminating lateral color aberration, maintaining relative structural simplicity.
3Length of moving object
If the focal length is made ultra-short for compact projection device, then the device is convenient to carry and adjust focus, but optical aberrations become more severe
Solution Approach 1:
The patent employs composite optical materials by combining lenses with different refractive indices and ABBE numbers. The first lens uses material with refractive index ≤1.64 and ABBE number Vd1, while the second lens uses material with refractive index >1.64 and ABBE number Vd2. This composite material approach allows the system to achieve ultra-short focal length while controlling optical aberrations through the complementary properties of different 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
The design effectively corrects image distortion and eliminates lateral color aberration while reducing manufacturing costs by optimizing the lens configuration and refractive indices, improving image quality and preventing structural interference.
Implementation Method 1
A refractive index of the first lens is less than or equal to 1.64, an ABBE number of the first lens represents Vd1, an ABBE number of the second lens represents Vd2, 0.4≦Vd2/Vd1≦1.2
Data Source
AI summary
A projection lens is applied to image projection of a projection device including an imaging unit. The projection lens includes a first lens group with a negative diopter and a second lens group with a positive diopter. The first lens group has a first lens having a first negative diopter. The second lens group is adjacent to the imaging unit and includes second, third, fourth, and fifth lenses. The second lens has a second negative diopter. The third and fourth lenses are between the first and second lenses. The fifth lens is between the imaging unit and the second lens and is an aspherical lens. A refractive index of the first lens is less than or equal to 1.64. An ABBE number of the first lens represents Vd1, an ABBE number of the second lens represents Vd2, 0.4≦Vd2/Vd1≦1.2, and Vd1<50.