Wide-Angle Projection Lens With Folded Optical Path
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Solution Overview
Problem
Current wide-angle projection lenses face challenges in minimizing aberrations and lens barrel length while maintaining a large numerical aperture, with existing designs suffering from complexity, manufacturability issues, and instability due to exposed mirror designs.
Innovation Solution
A wide-angle projection lens system utilizing a combination of spherical lenses, aspheric lenses, and a concave reflector, with a refraction system and reflection system configured to optimize focal length and reduce aberrations, including a first lens group with multiple spherical and aspheric lenses and a second lens group with specific refractive powers, and a concave reflector to improve image quality and reduce lens barrel length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If refraction type wide-angle lens with many refractive lenses is used, then wide-angle function is achieved, but lens barrel becomes too long and dispersed with increased complexity and low manufacturability
Solution Approach 1:
The patent combines refraction and reflection mechanisms into a hybrid optical system. The reflector folds the optical path to reduce the physical length of the lens barrel, while the coordinated arrangement of lenses and reflector eliminates the need for excessive refractive elements, thereby reducing both length and complexity simultaneously
Solution Approach 2:
The patent introduces a folded optical path using a reflector, transitioning from a linear one-dimensional arrangement to a multi-dimensional folded structure. This allows the optical system to achieve wide-angle coverage in a compact form factor by utilizing spatial folding rather than simply extending the lens barrel length
2Reliability
If reflection type wide-angle lens with whole reflective mirrors is used, then zero-dispersion is achieved, but manufacturability becomes very low due to requirement of many aspheric reflectors or free-surface reflectors
Solution Approach 1:
The patent applies different surface types to different parts of the optical system: spherical surfaces for lenses that are easier to manufacture, and selective aspheric surfaces only where necessary for aberration correction. This localized application of complexity maintains optical quality while improving overall manufacturability
Solution Approach 2:
The patent creates a composite optical system combining refractive lenses and reflective elements with different surface geometries (spherical and aspheric). This composite approach allows each component to be optimized for its specific function while maintaining compatibility with manufacturing capabilities
3Adaptability or versatility
If hybrid type with plane reflector is used, then optical properties and manufacturability are balanced, but lens barrel becomes longer sacrificing space to achieve wider angle
Solution Approach 1:
The patent uses a folded optical path with a reflector to achieve wide-angle coverage without proportionally increasing the lens barrel length. By folding the light path in three-dimensional space, the system achieves greater angular coverage within a compact linear footprint
4Length of moving object
If concave reflector is added to shorten lens barrel length, then focal length is shortened, but width or height of lens increases
Solution Approach 1:
The patent employs a folded optical path that redirects light in three-dimensional space, allowing the focal length to be shortened along the optical axis without proportionally increasing the lateral dimensions. The fold enables the light to traverse a longer effective path within a compact envelope
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 solution effectively shortens the focal length, decreases aberrations, and improves manufacturability by balancing optical properties, achieving high image quality and compactness with reduced lateral color and geometric distortion, suitable for large numerical apertures.
Implementation Method 1
the reflector will be added into the lens for turning
Implementation Method 2
the wide-angle lens is designed with the whole refractive lenses. The spherical lenses or the aspheric lenses are usually used in the wide-angle lens
Data Source
AI summary
A wide-angle projection system includes a refraction unit and a reflection unit. The refraction unit includes a first lens group of positive refractive power and a second lens group of negative refractive power. The second lens group is disposed between the first lens group and the reflection unit and the condition: 0.9<A/B<1.4 is satisfied, where A denotes a distance along an optical axis of the wide-angle projection system and between the refraction unit and the reflection unit, and B denotes a total length of the refraction unit along the optical axis.