Projection Lens with Non-Coaxial Aspheric Mirror
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Solution Overview
Problem
Designing a projection lens for wide-angle displays that minimizes aberrations while maintaining a compact form factor and low cost remains a challenge, as existing methods complicate the design process and increase manufacturing difficulties.
Innovation Solution
A projection lens configuration featuring a lens group with a non-coaxial optical axis and an aspheric mirror, where the aspheric mirror reflects an intermediate image formed by the lens group to produce a large image within a short range, utilizing an aspheric surface with a degree of aspheric formula less than or equal to 8 to reduce aberrations and simplify production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the length of the projection lens is extended to reduce aberration effects, then the imaging quality is improved, but the projection distance increases and the device becomes more complex
Solution Approach 1:
The patent employs an aspheric mirror with a specifically designed aspheric surface to correct optical aberrations. The aspheric shape allows for better control of light paths and reduction of distortion, field curvature, and astigmatism without requiring an extended projection lens length, thus maintaining compact form factor while improving imaging quality
Solution Approach 2:
The patent introduces a beam splitter as an intermediary optical element that directs light paths and enables the use of an aspheric mirror to correct aberrations. This intermediary component allows the system to achieve high imaging quality with a compact design by mediating between the light source and the image sensor
2Length of stationary object
If multiple reflectors are used to shorten the projection distance, then the compact form factor is improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent combines the functions of multiple optical elements into a single aspheric mirror that simultaneously corrects multiple types of aberrations (distortion, field curvature, astigmatism). This merging approach achieves the aberration correction that would otherwise require multiple separate reflectors, thereby reducing device complexity while maintaining compact projection distance
Solution Approach 2:
The aspheric mirror serves multiple functions: it acts as a primary optical element for image formation, corrects various optical aberrations, and enables compact projection geometry. This multi-functionality eliminates the need for separate correction elements, reducing overall device complexity
3Manufacturing precision
If spherical lenses and aspheric lenses are combined to reduce aberrations, then the imaging quality is improved, but the manufacturing precision requirements and cost increase
Solution Approach 1:
The patent replaces expensive, difficult-to-manufacture aspheric lenses with a more cost-effective aspheric mirror. The mirror can be manufactured using conventional techniques such as spin coating and curing, which are more accessible and less expensive than precision aspheric lens fabrication, thereby reducing manufacturing difficulty and cost while maintaining aberration correction capabilities
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
This configuration enables high-quality image projection with low aberration effects and reduced manufacturing costs, allowing for effective image enlargement within a limited range, while simplifying the design and production process.
Implementation Method 1
The aspheric mirror has a second optical axis and an aspheric surface, and the lens group is disposed between the object side and the aspheric mirror. The aspheric surface faces the lens group and reflects the intermediate image to form the image at an image side.
Implementation Method 2
The lens group has a first optical axis, and an intermediate image is formed by the lens group from the image source.
Data Source
AI summary
A projection lens configured to form an image from an image source which is disposed at an object side is provided. The projection lens includes a lens group and an aspheric mirror. The lens group has a first optical axis, and an intermediate image is formed by the lens group from the image source. The aspheric mirror has a second optical axis and an aspheric surface. The lens group is disposed between the object side and the aspheric mirror. The aspheric surface faces the lens group and reflects the intermediate image to form the image at an image side. The first optical axis is not coaxial with the second optical axis, and an offset of the image relative to the first optical axis is larger than or equal to 100%.