Projection Optical System Aspect Ratio Conversion via Anamorphic Lens
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Solution Overview
Problem
Existing projection optical systems face challenges in efficiently converting aspect ratios without increasing projector size or degrading image quality, as existing aspect ratio converters are either bulky, complex, or not designed for projection optical systems.
Innovation Solution
A projection optical system comprising a three-group configuration with a variable magnification optical system, an adjustment optical component with rotational asymmetry, and a correction optical component, allowing for aspect ratio conversion by adjusting the focal length differently in vertical and horizontal directions, and enabling the use of a retractable adjustment group to maintain image quality and reduce mechanical burden.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a front-disposed converter is used for aspect ratio conversion, then the aspect ratio can be converted, but the projector size increases and the optical system becomes more complex
Solution Approach 1:
The aspect ratio conversion function is nested within the existing projection optical system by integrating the conversion lens into the lens barrel structure. The conversion lens can be retracted into or extended from the lens barrel, allowing it to be part of the system when needed and concealed when not needed, thus avoiding increase in overall projector size and reducing apparent structural complexity.
Solution Approach 2:
The aspect ratio conversion lens is designed to be movable between an extended position (where it performs conversion) and a retracted position (where it is stored within the lens barrel). This dynamic configuration allows the system to adapt its structure based on operational requirements, providing conversion capability only when needed while maintaining a compact form factor otherwise.
2Adaptability or versatility
If a front-disposed converter is used for aspect ratio conversion, then the aspect ratio can be converted, but image quality deteriorates
Solution Approach 1:
The aspect ratio conversion lens acts as an intermediary optical element positioned within the existing projection optical path. By placing the conversion lens at a specific position where it can interact with the light beam without disrupting the overall optical design, the system achieves conversion while maintaining image quality. The conversion lens is designed to work harmoniously with the existing projection lenses rather than being an external add-on.
3Adaptability or versatility
If an anamorphic converter from image-taking systems is used directly in projection systems, then aspect ratio conversion can be achieved, but positional deviation of the image occurs due to tilting
Solution Approach 1:
Instead of tilting the conversion lens to achieve aspect ratio conversion (which causes image positional deviation in image-taking systems), the patent inverts the approach by keeping the conversion lens optical axis aligned with the projection optical axis and achieving conversion through the lens's inherent anamorphic power. This inversion of the conventional tilting method eliminates image positional deviation while maintaining conversion capability.
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 efficient aspect ratio conversion without increasing projector size, maintaining image quality, and allowing for precise adjustment of the projected image, including the ability to project images at different aspect ratios without degrading brightness or introducing chromatic aberration.
Implementation Method 1
an adjustment optical component (40) with a surface rotationally asymmetrical to an optical axis, when defining at least one direction of the vertical direction and the horizontal direction of the optical modulator as an adjustment direction in which conversion adjustment using compression or extension is performed, the adjustment optical component (40) having at least one optical system which is different in power between the vertical direction and the horizontal direction
Data Source
AI summary
A projection optical system which, when projecting an image of an optical modulator onto a projection surface on an enlarged scale, differs the aspect ratio of the image of the optical modulator and the aspect ratio of the image projected onto the projection surface, and includes, in order from the projection surface, a first group which is an enlargement optical system; a second group includes an adjustment optical component with a surface rotationally asymmetrical to an optical axis, when defining at least one direction of the vertical direction and the horizontal direction of the optical modulator as an adjustment direction in which conversion adjustment using compression or extension is performed, the adjustment optical component having at least one optical system which differs in power between the adjustment direction and another direction; and a third group which has a correction optical component with a surface rotationally symmetrical to the optical axis.