Fixed-Focus Projector Lens for Compact Wide-Angle Imaging
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Solution Overview
Problem
Existing projection lenses with a wide-angle field of view and favorable image performance suffer from large lens length and diameter, leading to poor installation adaptability and design restrictions.
Innovation Solution
A fixed-focus lens design featuring a first lens group with positive refractive power and a second lens group, including aspherical lenses, arranged in a telecentric system, which satisfies specific conditional expressions to reduce size and correct aberrations while maintaining a wide-angle field of view.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a projection lens uses a conventional design with negative and positive lens groups to achieve wide-angle field of view and favorable image performance, then image quality is improved, but lens length and lens diameter become large
Solution Approach 1:
The patent changes the refractive power parameters of lens groups, specifically making the first lens group have positive refractive power instead of negative, and adjusting the focal lengths and spacing of lens groups to achieve compact dimensions while maintaining wide-angle field of view and image quality
Solution Approach 2:
The patent introduces aspherical lenses (lens closest to enlargement side or second closest) to correct aberrations and improve image performance, allowing for more compact lens design by reducing the need for additional correction elements that would increase lens length
2Manufacturing precision
If a projection lens uses a conventional design with negative and positive lens groups to achieve wide-angle field of view and favorable image performance, then image quality is improved, but lens diameter becomes large
Solution Approach 1:
The patent adjusts the refractive power distribution and focal length parameters of lens groups to reduce beam height at lens surfaces, thereby reducing lens diameter while maintaining wide-angle field of view and image quality through optimized optical path control
3Adaptability or versatility
If a projection lens reduces lens length and diameter to improve installation adaptability, then installation flexibility is improved, but image performance may deteriorate
Solution Approach 1:
The patent uses aspherical lenses to correct aberrations in the compact lens design, maintaining image performance despite reduced lens length and diameter by compensating for optical path deviations through aspherical surface geometry
Solution Approach 2:
The patent applies different refractive powers and aspherical surfaces to specific lens elements at critical positions (enlargement side and reduction side) to locally optimize aberration correction and maintain overall image performance in the compact configuration
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 lens achieves a compact size, high-quality image projection with a wide-angle field of view, reducing product size and cost without compromising resolution performance.
Implementation Method 1
a lens closest to the enlargement side or a lens second closest to the enlargement side in the first lens group is an aspherical lens
Implementation Method 2
the reduction side of the fixed-focus lens is a telecentric system
Implementation Method 3
a first lens group; an aperture stop; and a second lens group sequentially arranged from an enlargement side toward a reduction side, the first and second lens groups each having positive refractive power
Data Source
AI summary
A fixed-focus lens includes: a first lens group; an aperture stop; and a second lens group sequentially arranged from an enlargement side toward a reduction side, the first and second lens groups having positive refractive power. In the first group, a lens closest or second closest to the enlargement side is an aspherical lens. The fixed-focus lens satisfies conditional expressions below.ω>45(1)0.15<L1H/LL<0.4(2)2.5<BF/F<3.5(3)The value ω represents the largest half viewing angle of the lens, the value L1H represents the height of the beam passing through the top of the maximum image height at the surface of the lens closest to the enlargement side, the value LL is the length of the lens, the value BF represents the back focal length in air, and the value F represents the focal length of the entire lens.