Compact Projection Lens with Concave Reflective Surface
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Solution Overview
Problem
In projection systems with a concave reflective surface on the magnifying side, shortening the projection distance leads to an increase in the size of the reflective surface, causing the system to become larger and less efficient.
Innovation Solution
A projection system with a second optical system comprising a lens having a first transmissive surface, a reflective surface, and a second transmissive surface, where the reflective surface is concave and the second transmissive surface is convex, allowing for a more compact design by suppressing the increase in the size of the reflective surface even at short projection distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the projection distance is shortened in a projection system with a concave reflective surface, then the projection system becomes more compact, but the size of the reflective surface increases
Solution Approach 1:
The projection system is divided into two separate optical systems: a first optical system (refractive) and a second optical system (reflective). This segmentation allows each system to handle specific portions of the optical path, enabling the reflective surface to maintain a smaller size while achieving short projection distance through the combined action of both systems.
Solution Approach 2:
The patent combines a refractive optical system and a reflective optical system into a unified projection system. The first optical system forms an intermediate image, and the second optical system further processes this image to form the final projected image. This merging of different optical principles allows the system to achieve short projection distance without requiring a large reflective surface.
2Manufacturing precision
If the size of the reflective surface is increased to maintain image quality at short projection distances, then the projection system becomes larger and less efficient, but the image formation quality improves
Solution Approach 1:
By segmenting the optical system into refractive and reflective portions, each component can be optimized for its specific function. The first optical system handles initial image formation with controlled aberrations, while the second optical system completes the projection with minimal reflective surface size, together achieving high image quality without excessive system size.
Solution Approach 2:
The patent optimizes specific parameters including the focal lengths, spacing, and configuration of the first and second optical systems. By carefully adjusting these parameters, the system achieves optimal image formation quality while maintaining a compact size and avoiding the need for a large reflective surface.
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 maintains the system's efficiency and compactness by preventing the reflective surface from enlarging when the projection distance is shortened, reducing field curvature and aberrations, and ensuring optimal image formation.
Implementation Method 1
The projection system includes a first optical system and a second optical system sequentially arranged from a demagnifying side toward a magnifying side. The second optical system is a lens with a first transmissive surface, a reflective surface, and a second transmissive surface.
Implementation Method 2
The reflective surface has a concave shape. The second transmissive surface has a convex shape protruding toward the magnifying side.
Data Source
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AI summary
A projection system is formed of a first optical system and a second optical system sequentially arranged from the demagnifying side toward the magnifying side and forms a first intermediate image and a second intermediate image in positions between a demagnifying-side image formation plane and a magnifying-side image formation plane of the projection system. The second optical system is a lens. The lens has a first transmissive surface, a reflective surface, and a second transmissive surface. The reflective surface has a concave shape, and the second transmissive surface has a convex shape protruding toward the magnifying side. An imaginary line specified in the lens inclines with respect to an imaginary vertical line perpendicular to the imaginary axis in a plane YZ, and the intermediate image is located between the first transmissive surface and the reflective surface.