Variable Magnification Optical System with Reflective Element
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Solution Overview
Problem
Existing variable magnification optical systems require large mirrors and significant changes in projection distance to achieve desired magnification, leading to increased manufacturing costs, system size, and instability due to weight and center of gravity issues.
Innovation Solution
A variable magnification optical system that uses a combination of refractive optical elements and a reflective optical element with a positive power, allowing for changes in magnification without altering the projected angle of view by adjusting the distance between the reflective optical element and the screen, thereby reducing the size of the reflective optical element and maintaining a constant projected angle of view.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a large mirror is used to achieve sufficient magnification without changing projection distance, then the magnification function is achieved, but the system size and manufacturing cost increase
Solution Approach 1:
The patent divides the optical system into multiple lens groups (first lens group with negative power, second lens group with positive power, third lens group with positive power) that can move independently. This segmentation allows each group to contribute differently to the magnification function, enabling variable magnification without requiring a single large mirror. The first lens group moves to change magnification while the other groups remain relatively stationary or move less.
2Adaptability or versatility
If the projection distance is changed significantly to achieve desired magnification, then the magnification is achieved, but the system stability decreases due to weight and center of gravity issues
Solution Approach 1:
The patent implements a dynamic optical system where lens groups can move along the optical axis to adjust magnification. The first lens group is designed to move to change the magnification ratio, while the optical system as a whole remains relatively stable. This dynamic adjustment mechanism allows magnification changes without requiring significant changes in projection distance that would affect system stability.
3Adaptability or versatility
If a high-power mirror is used to achieve wide projected angle, then the projected angle increases, but the mirror size and manufacturing precision requirements increase
Solution Approach 1:
The patent changes the optical parameters by using a combination of lens groups with different powers (negative and positive) instead of relying on a single high-power mirror. The first lens group with negative power and the second and third lens groups with positive power work together to achieve the desired projected angle of view. This approach distributes the optical power requirements across multiple elements, reducing the precision requirements for each individual component compared to using a single high-power mirror.
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 projection with sufficient magnification without the need for large mirrors, reducing manufacturing costs and system size while maintaining image quality and stability by allowing for smaller changes in projection distance and preventing distortion.
Implementation Method 1
a refractive optical system including a first optical system with plural refractive optical elements and a second optical system with plural refractive optical elements
Implementation Method 2
a reflective optical element with a certain power; The optical path of light which has passed through the second optical system is folded by the reflective optical element so that an enlarged image can be projected
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
A variable magnification optical system projects an image onto a screen with a sufficient magnification without requiring a large-sized mirror. The variable magnification optical system includes a first optical system through which a light beam modulated with an image signal corresponding to the image is passed; a second optical system disposed downstream of the first optical system in a direction of travel of the light beam along an optical axis; and a reflective optical element having a magnification power that is configured to reflect the light beam from the second optical system toward the screen. A magnification of the image projected on the screen is changed by moving the reflective optical element relative to the object plane, thus changing a distance between the screen and the reflective optical element, while an incident angle of the light beam on the screen is maintained substantially constant.