Projection Optical System Aberration Correction and Dust Protection
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Solution Overview
Problem
Existing projection optical systems face issues with aberration correction and imaging performance due to dust or dirt adhesion on reflective surfaces, particularly in systems with a reflective optical component exposed to the air.
Innovation Solution
A projection optical system comprising a combination of a reflective optical system with a convex mirror and a refractive optical system, including a single aspheric lens with positive or negative refractive power, positioned closer to the magnification side, which forms an intermediate image and corrects aberrations while minimizing the influence of foreign matter adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a reflective optical system with an exposed mirror surface is used, then the system can achieve compact configuration and wide angle, but the imaging performance deteriorates due to adhesion of foreign matter such as dust or dirt onto the reflective surface
Solution Approach 1:
The patent introduces a protective lens as an intermediary component between the external environment and the convex mirror's reflective surface. This lens serves as a mediator that allows light to pass through while preventing foreign matter from directly contacting and adhering to the mirror surface, thus protecting the imaging performance while maintaining the compact reflective optical system configuration
Solution Approach 2:
The protective lens acts as a thin transparent barrier (similar to a shell or film) that covers the convex mirror surface. This thin protective layer allows optical functionality to be maintained while providing physical protection against dust and dirt adhesion, resolving the contradiction between exposed surface benefits and contamination risks
2Device complexity
If the reflective surface is exposed to the outside air, then the system structure is simplified, but foreign matter adhesion causes deterioration of imaging performance
Solution Approach 1:
The protective lens serves as an intermediary barrier between the external environment and the convex mirror. It allows the system structure to remain relatively simple while introducing a thin protective element that prevents foreign matter from directly contacting the reflective surface, thus reducing the harmful effects of dust and dirt adhesion
3Ease of operation
If a projection optical system with exposed mirror is used, then installability in indoor space is improved, but adhesion of foreign matter reduces imaging performance
Solution Approach 1:
The protective lens acts as a mediator that enables the compact projection optical system to be installed in indoor spaces while simultaneously protecting the convex mirror from foreign matter adhesion. This intermediary component ensures that the ease of installation is not compromised by the need to protect against contamination
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 system achieves improved imaging performance and reduced susceptibility to foreign matter adhesion, enabling effective aberration correction and maintaining high performance even in wide-angle configurations with a total angle of view greater than 130 degrees.
Implementation Method 1
a convex mirror that is disposed to be closer to a magnification side than the intermediate image
Implementation Method 2
at least one lens that has a positive or negative refractive power and is disposed in an optical path so as to be closer to the magnification side than the convex mirror
Data Source
AI summary
A projection optical system forms an intermediate image at a position conjugate to a reduction side imaging surface, and forms a final image conjugate to the intermediate image on a magnification side imaging surface. The projection optical system includes a convex mirror disposed to be closer to the magnification side than the intermediate image and at least one lens that has a positive or negative refractive power and is disposed in an optical path so as to be closer to the magnification side than the convex mirror.