Projection Lens Structure with Plastic Aspheric Meniscus Lens
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Solution Overview
Problem
Current projection lens structures with multiple groups of lenses face challenges in achieving high image quality while maintaining a simple structure and low manufacturing costs, particularly in terms of focal length arrangement and aperture stop optimization.
Innovation Solution
A projection lens structure comprising multiple groups of lenses with specific dioptric values, including a first group with a plastic aspheric meniscus lens, a second group with positive dioptric lenses, a third group with a positive doublet, and a fourth group with negative dioptric doublets, along with an aperture stop between the third and fourth groups, allowing for operation in both wide-angle and telescope modes with a zoom ratio of 1.0×-1.5×.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple groups of lenses are used to improve image quality, then image quality is improved, but device complexity increases
Solution Approach 1:
The lens system is divided into four distinct groups with specific dioptric values (first group: -25~-80mm, second group: positive, third group: +25~+80mm, fourth group: negative), each group performing specific optical functions. This segmentation allows optimized image quality while maintaining manageable complexity through modular design
Solution Approach 2:
Each lens group is designed with specific local characteristics - the first group uses plastic aspheric meniscus lenses for specific focal lengths, the second and third groups use positive dioptric lenses, and the fourth group uses negative dioptric doublets. This local optimization of lens properties achieves high image quality while controlling overall system complexity
2Manufacturing precision
If complex lens arrangements are used to achieve high image quality, then image quality is improved, but manufacturing cost increases
Solution Approach 1:
The patent optimizes specific parameters including focal lengths (first group: -25~-80mm, third group: +25~+80mm), aperture stop position (between third and fourth groups), and dioptric values to achieve high image quality. These parameter optimizations allow standard manufacturing processes to produce high-quality lenses without requiring expensive specialized fabrication
Solution Approach 2:
The lens system combines different materials with specific properties - plastic aspheric meniscus lenses in the first group and glass lenses in subsequent groups. This composite material approach allows each lens type to be manufactured using optimized processes for its specific material, controlling overall manufacturing cost while achieving high image quality
3Manufacturing precision
If aperture stop is optimized to enhance image quality, then image quality is improved, but device complexity increases
Solution Approach 1:
The aperture stop is positioned as an intermediary element between the third and fourth lens groups, serving as a mediator that controls light paths and optimizes image quality. This intermediate placement allows the aperture stop to function effectively without requiring complex integration with the lens groups, maintaining relatively simple overall structure
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 structure achieves high image quality with a simple design and low manufacturing costs, maintaining optimal focal lengths and aperture settings across different modes, enhancing image projection capabilities.
Implementation Method 1
a first lens being a plastic aspheric lens in a meniscus shape with a focal length between −25 ̃−80 mm
Implementation Method 2
multiple groups of lenses operated together to manufacture the projection lens with simple structure and low costs
Data Source
AI summary
A projection lens structure mainly includes a first group of lenses with a negative dioptric value, a second group of lenses with a positive dioptric value, a third group of lenses with a positive dioptric value and a fourth group of lenses with a negative dioptric value. The first group of lenses further includes at least a first lens and a second lens, of which the first lens ha a plastic aspheric lens in a meniscus shape with a focal length between −25˜−80 mm. The second group of lenses further includes at least a third lens. The third group of lenses further includes at least a first doublet with a focal length between 25˜80 mm. The fourth group of length further includes at least a group of doublets, a fourth lens and a fifth lens.