Fixed Focus Lens Design Reducing Aspheric Fabrication Costs
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Solution Overview
Problem
Conventional projection lenses with multiple aspheric lenses face challenges in production yields and fabrication costs due to high precision requirements and surface complexity, leading to increased complexity and costs.
Innovation Solution
A fixed focus lens design with a limited number of aspheric lenses, utilizing a first lens group with negative refractive power and a second lens group with positive refractive power, including compound lenses, to maintain optical performance while reducing the number of aspheric surfaces, thereby simplifying fabrication and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple aspheric lenses are used to achieve large effective apertures and low distortion, then optical performance is improved, but manufacturing precision requirements and fabrication costs increase
Solution Approach 1:
The patent replaces expensive aspheric lenses with spherical lenses that can be manufactured more cheaply and with lower precision requirements. While aspheric lenses provide better optical performance, they are difficult and costly to manufacture. The invention uses spherical lenses combined with a reflective optical path to achieve acceptable optical performance at lower cost and manufacturing complexity.
Solution Approach 2:
The patent substitutes refractive optical elements (aspheric lenses) with a reflective optical system using mirrors. The light reflection path includes a first reflection surface and a second reflection surface that work together to achieve the desired optical performance without requiring multiple complex aspheric lenses, thereby reducing manufacturing precision requirements.
2Reliability
If multiple aspheric lenses are used to achieve low chromatic aberration, then optical performance is improved, but fabrication costs and production complexity increase
Solution Approach 1:
The patent replaces expensive aspheric lenses with simpler spherical lenses that are easier and cheaper to manufacture. The spherical lenses, combined with the reflective optical path and selective use of materials, achieve acceptable chromatic aberration control without the high fabrication costs and complexity associated with multiple aspheric lenses.
Solution Approach 2:
The patent employs a composite optical system that combines spherical lenses made from different materials (including plastic and glass lenses with different Abbe numbers) with reflective surfaces. This composite approach allows chromatic aberration control through material selection and optical path design rather than relying solely on complex aspheric lens surfaces.
3Reliability
If the number of aspheric lenses is increased to improve optical performance, then image quality is improved, but production yields decrease
Solution Approach 1:
The patent reduces the number of aspheric lenses in favor of spherical lenses that have higher production yields. Spherical lenses are easier to manufacture with consistent quality, leading to fewer defects and higher production yields while maintaining acceptable image quality through the reflective optical path design.
Solution Approach 2:
The patent extracts and removes aspheric lenses from the optical system, replacing them with spherical lenses and reflective elements. This extraction of complex aspheric surfaces simplifies the manufacturing process, increases production yield, and reduces the likelihood of manufacturing defects while maintaining functional performance.
4Reliability
If multiple aspheric lenses are used to achieve large effective apertures, then optical performance is improved, but fabrication costs increase
Solution Approach 1:
The patent replaces expensive aspheric lenses with cheaper spherical lenses that can be manufactured more easily. The reflective optical path design allows the system to achieve large effective apertures without requiring multiple costly aspheric lenses, thereby reducing fabrication costs while maintaining optical performance.
Solution Approach 2:
The patent substitutes refractive aspheric lenses with a reflective optical system that achieves large effective apertures more cost-effectively. The combination of spherical lenses and reflective surfaces provides the necessary aperture performance without the high fabrication costs associated with multiple aspheric lenses.
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 reduced fabrication costs and increased production efficiency without compromising optical performance by limiting the number of aspheric surfaces and maintaining a whole group focusing operation, resulting in a cost-effective and efficient optical system.
Implementation Method 1
a first lens group G1 with a negative refractive power, an aperture stop S, and a second lens group G2 with a positive refractive power which are arranged in order from a first side to a second side
Implementation Method 2
The first lens group has at least two lenses including at least one aspheric lens
Data Source
AI summary
A fixed focus lens includes a first lens group with a negative refractive power, an aperture stop, and a second lens group with a positive refractive power arranged in order from a first side to a second side. The first lens group has at least two lenses including at least one aspheric lens. The second lens group includes at least five lenses, the at least five lenses comprising a first compound lens and a second compound lens. A difference between a maximum Abbe number and a minimum Abbe number for all lenses of the first compound lens is greater than 50, and a difference between a maximum Abbe number and a minimum Abbe number for all lenses of the second compound lens is greater than 45.