Projection System Optical Element Refraction Reflection
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Solution Overview
Problem
The existing projection systems face challenges in shortening the projection distance while maintaining image quality and resolution, particularly due to difficulties in designing the optical systems with reflection surfaces and transmissive surfaces effectively.
Innovation Solution
The projection system incorporates a first optical system and a second optical system with an optical element having a reflection surface, a first transmissive surface, and a second transmissive surface, along with a reflector, which are strategically positioned to refract and direct light fluxes, allowing for a shorter projection distance without compromising image quality by suppressing aberrations and inclination of intermediate images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a conventional projection system with reflection mirror and refractive optical system is used, then the system can form projection images, but the projection distance cannot be sufficiently shortened due to design difficulties
Solution Approach 1:
The patent combines the reflection surface and transmissive surfaces into a single integrated optical element. This optical element has a reflection surface facing the reduction-side image formation plane and a transmissive surface facing the enlargement-side image formation plane, allowing it to perform both reflection and refraction functions simultaneously. This merging resolves the contradiction by simplifying the optical system structure while enabling shorter projection distance.
Solution Approach 2:
The optical element serves multiple functions: it acts as both a reflective surface for forming intermediate images and a transmissive surface for final image projection. Additionally, the reflector and optical element work together to control light flux in multiple directions. This multi-functionality reduces the number of separate components needed, thereby shortening the projection distance without excessive complexity.
2Length of moving object
If the projection distance is shortened, then the system becomes more compact, but image quality deteriorates due to increased aberrations and intermediate image inclination
Solution Approach 1:
The patent applies different surface characteristics to different parts of the optical element. The reflection surface has specific curvature properties optimized for intermediate image formation, while the transmissive surface has different curvature properties optimized for final image projection. This local optimization of surface qualities allows the system to maintain high image quality even with shortened projection distance by compensating for aberrations locally.
Solution Approach 2:
The patent optimizes specific parameters including the curvature radii of the reflection and transmissive surfaces, the relative positioning between the optical element and reflector, and the refractive indices of optical materials. By carefully adjusting these parameters, the system achieves short projection distance while maintaining image quality through aberration suppression.
3Illumination intensity
If a reflection mirror is used in the projection system, then the optical path can be controlled, but light loss occurs at the periphery and contrast reproduction ratio decreases
Solution Approach 1:
The patent replaces the conventional reflection mirror with an optical element that uses refraction in addition to reflection. The transmissive surface of the optical element refracts light flux to reach the enlargement-side image formation plane, providing an alternative path that reduces peripheral light loss. This substitution of pure reflection with a combination of reflection and refraction mechanisms improves light utilization efficiency and contrast reproduction.
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 a shorter focal length and improved resolution, reducing light loss at the periphery and maintaining high contrast reproduction ratios, thus enhancing the projection system's performance and efficiency.
Implementation Method 1
an optical element (33) having a reflection surface (41), a first transmissive surface (42), and a second transmissive surface (43)
Implementation Method 2
The intermediate image (35) is formed between the first optical system (31) and the reflection surface (41) of the optical element (33)
Data Source
AI summary
A projection system includes a first optical system and a second optical system including an optical element and a reflector and disposed at the enlargement side of the first optical system. The optical element has a reflection surface, a first transmissive surface disposed at the enlargement side of the reflection surface, and a second transmissive surface disposed at the enlargement side of the first transmissive surface. The reflector is disposed at the enlargement side of the reflection surface and at the reduction side of the first transmissive surface. The reflector is disposed between the optical element and the first optical system in the direction along a first optical axis of the first optical system.