Compact Wide-Angle Projection Lens for Aberration Correction
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Solution Overview
Problem
Existing projection lenses have large lens diameters and lengths, affecting the size, weight, and design flexibility of projection apparatuses, and they do not effectively correct various aberrations.
Innovation Solution
A projection lens design with a first lens group having positive or negative refractive power and a second lens group with positive refractive power, arranged sequentially, and configured to satisfy specific conditional expressions for compact size and aberration correction, including a first sub-lens group with negative refractive index and a second sub-lens group with positive refractive index.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a projection lens uses a conventional lens structure with large lens diameter and length, then the lens can achieve adequate aberration correction and imaging performance, but the size and weight of the projection apparatus increase, and design flexibility is reduced
Solution Approach 1:
The lens is divided into multiple lens groups (first lens group with negative refractive power, second lens group with positive refractive power) that are sequentially arranged. Each group contains specific lens elements configured to correct particular aberrations, allowing the system to achieve adequate aberration correction with a more compact overall structure, thereby reducing the weight of the projection apparatus.
Solution Approach 2:
The patent employs specific refractive index values and curvature radii for each lens element, carefully optimized to satisfy conditional expressions that balance aberration correction with compact size. By precisely controlling parameters such as the refractive power distribution and lens spacing, the system achieves effective aberration correction without requiring excessively large lens diameter or length.
2Volume of moving object
If the lens diameter and length are reduced to make the projection apparatus more compact, then design flexibility and space utilization improve, but aberration correction becomes difficult to maintain
Solution Approach 1:
The lens system is segmented into multiple functional groups with specific refractive power characteristics. The first lens group (negative refractive power) and second lens group (positive refractive power) are arranged sequentially to work together, allowing compact overall dimensions while maintaining the capability to correct various aberrations through the coordinated action of individual lens elements within each group.
Solution Approach 2:
The lens system utilizes composite optical design combining lens elements with different refractive indices and optical properties. By integrating multiple lens types (meniscus lenses, biconcave lenses, cemented lenses) with specific refractive power characteristics, the system achieves effective aberration correction in a compact configuration, avoiding the need for excessively large lens dimensions.
3Reliability
If more lens elements are added to improve aberration correction, then imaging quality improves, but the lens length and complexity increase
Solution Approach 1:
The lens is organized into two main groups with distinct refractive power characteristics. The first lens group containing negative refractive power elements and the second lens group containing positive refractive power elements are sequentially arranged, providing a structured approach to aberration correction that improves imaging quality while controlling structural complexity through clear functional separation.
Solution Approach 2:
Multiple lens elements with different functions are combined into integrated lens groups. For example, the first lens group combines negative refractive power elements that work together to correct specific aberrations, and the second lens group combines positive refractive power elements for additional correction. This merging approach achieves improved imaging quality while avoiding excessive complexity by organizing elements into coherent functional units.
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 achieves a compact projection lens with a wide viewing angle, favorable resolution, and effective aberration correction, including chromatic aberration, while ensuring an appropriate back focal length for space and reducing lens diameter and cost.
Implementation Method 1
a first lens group having positive or negative refractive power; an aperture stop; and a second lens group having positive refractive power that are sequentially arranged from an enlargement side
Data Source
AI summary
A projection lens includes first lens group having positive or negative refractive power; aperture stop; and second lens group having positive refractive power that are sequentially arranged from enlargement side. The first lens group is configured with first sub-lens group having negative refractive index and second sub-lens group having positive refractive index that are sequentially arranged from enlargement side, and projection lens satisfies conditional expressions:0.1<1/fg1p-1/fg1m<0.25(1)ω>50(2)2.5<(DL1×LL)×F/IH2<6.5(3)3.0<BF/F<5.0(4)In Conditional Expressions (1) to (4), value fg1p is the combined focal length of first sub-lens group G1m, value fg1m is the combined focal length of second sub-lens group G1p, value ω is maximum half viewing angle of projection lens, value IH is image circle, value DL1 is the radius of lens closest to a screen, value LL is the total length of projection lens, value F is the combined focal length of all lenses, and value BF is the back focal length in air.