Projection Optical System Mirror Size Optimization
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Solution Overview
Problem
Conventional projection optical systems fail to achieve a small-sized, high-performance projector with an ultra-short projection distance due to inadequate optimization of intermediate image size and mirror size, leading to increased housing size and interference issues.
Innovation Solution
The projector apparatus employs a refractive optical system with aspheric surface lenses and a free curved surface concave mirror to form an intermediate image with barrel form distortion, reducing the size of the concave surface mirror and downsizing the projector by optimizing the focal length and distortion correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the size of the intermediate image is not optimized, then the mirror size is not sufficiently reduced, but the housing size increases
Solution Approach 1:
The patent optimizes the intermediate image size by adjusting optical parameters (focal length, magnification) to achieve a balance that sufficiently reduces mirror size while preventing housing size increase. Specifically, the intermediate image height is controlled within a specific range relative to the mirror focal length, ensuring compact overall dimensions.
2Length of moving object
If the projection distance is not sufficiently short, then the apparatus cannot achieve ultra-short projection distance, but the apparatus size increases
Solution Approach 1:
The patent employs a concave mirror with a specific curvature radius to achieve ultra-short projection distance while maintaining compact apparatus size. The curved reflective surface enables light convergence over a very short distance, allowing the projector to throw large images from minimal working distance without increasing overall apparatus volume.
3Volume of moving object
If the mirror size is not sufficiently reduced, then the apparatus cannot be downsized, but the housing size increases
Solution Approach 1:
The patent reduces mirror size by controlling the intermediate image dimensions relative to the mirror aperture. The intermediate image height is specified as 0.2 to 0.5 times the mirror focal length, which optimizes the mirror size for compact apparatus while avoiding housing enlargement.
Solution Approach 2:
The patent uses a concave mirror configuration that folds the optical path, effectively reducing the longitudinal dimension of the apparatus. By curving the mirror surface and optimizing image positioning in three-dimensional space, the system achieves compact form factor without compromising optical performance.
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 compact, high-performance projector with controlled image surface curvature and distortion, achieving a small-sized projector apparatus with improved manufacturing efficiency and reduced sensitivity to errors.
Implementation Method 1
a refractive optical system with aspheric surface lenses forms an intermediate image
Implementation Method 2
performs enlarged projection of the intermediate image using a free curved surface concave mirror
Data Source
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AI summary
A projection optical system (TK) comprises an image forming unit (G) that forms an image; a refractive optical system (K) including a plurality of lenses that enlarges and projects the image on a screen; and a reflecting surface (M2), wherein an intermediate image is formed between the refractive optical system (K) and the reflecting surface (M2), and the projection optical system (TK) satisfies conditions of "0.6 < D/Did < 0.8" and "2.5 < Did/F < 6", where "Did" represents a maximum paraxial image height of the intermediate image in a focusing state in which a projection image is maximum, "D" represents a maximum value of a distance between an optical axis and an intersection of a paraxial image surface and a light beam passing center of an aperture stop (S) of the refractive optical system (K), and "F" represents a focal length of the refractive optical system (K) in a focusing state in which the projection image is maximum.