Projection Optical System with 90-Degree Light Path Bending
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Solution Overview
Problem
Existing projection optical systems with wide angles of view face challenges in achieving both short projection distances and high image quality while maintaining a compact size, often requiring lengthy optical systems and increased costs due to multiple optical elements for bending the light path.
Innovation Solution
A projection optical system comprising a first optical system and a second optical system, where the first optical system includes a reflecting optical element that bends the light path only once by 90 degrees, allowing for a compact design that satisfies specific conditional formulas to optimize the ratio of optical system lengths and focal lengths, thereby reducing the projection-direction length and improving image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If a relay-type projection optical system is adopted to achieve wide angle of view, then the angle of view is improved, but the total length of the projection optical system is extended
Solution Approach 1:
The patent introduces a light path bending mechanism that changes the spatial arrangement from a linear configuration to a folded configuration. By bending the light path at approximately 90 degrees between the first and second optical systems, the optical system achieves a wide angle of view while keeping the projection-direction length short, effectively trading spatial arrangement for performance improvement.
2Length of moving object
If the light path is bent multiple times to shorten the projection optical system, then the length is reduced, but the number of optical elements is increased and cost is increased
Solution Approach 1:
Instead of bending the light path multiple times or excessively, the patent applies a single light path bending of approximately 90 degrees between the first and second optical systems. This partial action is sufficient to achieve the desired shortening effect while avoiding the increased complexity and cost associated with multiple bending elements.
3Length of moving object
If the light path is bent at the position of the intermediate image to shorten the projection optical system, then the projection direction length is reduced, but it is difficult to achieve both wide angle of view and high image quality
Solution Approach 1:
The patent divides the projection optical system into two distinct optical systems: a first optical system that forms the intermediate image and a second optical system that projects the intermediate image onto the screen. The light path bending is positioned between these two segmented systems, allowing each system to be optimized independently for both wide angle of view and high image quality while maintaining a compact projection-direction length.
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 large screen projection with high image quality and a short projection distance while minimizing the size and cost of the projection apparatus by reducing the number of optical elements needed for light path bending, achieving a well-balanced optical performance and miniaturization.
Implementation Method 1
a reflecting optical element that bends a light path between the first-A optical system and the first-B optical system
Data Source
AI summary
A projection optical system that enlarges and projects an image displayed on an image display includes: a first optical system; and a second optical system. The projection optical system is a monofocal lens or a zoom lens. The first optical system and the second optical system are arranged, in order starting with the first optical system, from an enlargement side of the projection optical system. The second optical system forms an intermediate image of the image between the first optical system and the second optical system. The first optical system enlarges and projects the intermediate image. The first optical system includes: a first-A optical system and a first-B optical system in order from the enlargement side; and a reflecting optical element that bends a light path between the first-A optical system and the first-B optical system.