Adjustable Mirror Optical System for Ultra-Short Throw Projection
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Solution Overview
Problem
Conventional image displaying apparatuses face challenges in reducing the size of the optical system while maintaining the ability to project large format images at ultra-short distances, leading to potential image quality degradation due to positional displacements of the lens and mirror optical systems.
Innovation Solution
An image displaying apparatus with a projection optical system comprising a lens optical system and a mirror optical system, where an intermediate image is formed between the image displaying element and a concave second mirror, and the first mirror is adjustable to correct positional dispersions, ensuring optimal image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a lens optical system with a large outer diameter is used to extend the angle of view for short distance projection, then the projection distance is reduced, but the projector size becomes large
Solution Approach 1:
The patent introduces a folding mirror to fold the optical path, changing the spatial arrangement from a straight-line configuration to a folded configuration. This allows the optical system to achieve a long effective optical path length while maintaining a compact physical footprint, resolving the contradiction between projection distance and projector size
2Volume of stationary object
If a long distance is provided between the lens optical system and the curved mirror to reduce the optical system size, then the optical system becomes compact, but the projection optical system length increases and interferes with further distance reduction
Solution Approach 1:
The folding mirror folds the optical path in a direction perpendicular to the main optical axis, allowing the distance between the lens optical system and curved mirror to be extended without increasing the overall projection optical system length in the direction toward the screen. This resolves the contradiction by utilizing a different spatial dimension
3Length of moving object
If the divergence of light incident on the mirror optical system is increased to project large format images at ultra-short throw, then the projection distance is reduced, but the refraction angle increases causing large positional displacement effects and image quality degradation
Solution Approach 1:
The patent makes the first mirror adjustable in position and angle, allowing dynamic compensation for the increased refraction angles caused by higher light divergence. This adaptability enables the system to maintain image quality despite the increased divergence required for ultra-short throw projection
4Ease of manufacture
If the position of the lens optical system or mirror optical system is displaced, then the optical system becomes simpler to manufacture, but the field curvature varies greatly causing drastic degradation of image quality
Solution Approach 1:
The adjustable first mirror acts as a feedback mechanism that compensates for positional displacements in the optical system. By allowing adjustment of the first mirror's position and angle, the system can correct for manufacturing tolerances and assembly variations, maintaining image quality despite simpler manufacturing processes
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
Enables the projection of large format images at ultra-short distances without degrading image quality, by adjusting the first mirror to compensate for positional errors between the lens and mirror optical systems, thus maintaining image quality.
Implementation Method 1
a lens optical system (8) and a mirror optical system including a first mirror (9) and a second mirror (10) which is a concave mirror
Implementation Method 2
a second mirror (10) which is a concave mirror
Data Source
AI summary
Disclosed is an image displaying apparatus including an image displaying element configured to form an image to be projected and a projection optical system having a positive refractive power and configured to project the image to be projected onto a screen, wherein the projection optical system includes a lens optical system and a mirror optical system, the lens optical system including plural lens groups, the mirror optical system including a first mirror and a second mirror, the second mirror being a concave mirror, wherein an intermediate image of a pixel of the image displaying element is formed between the image displaying element and the second mirror, and wherein the first mirror is held to be capable of adjusting a position thereof.