Secondary Mirror Alignment Device for Optical Systems
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Solution Overview
Problem
Existing alignment devices for laser optical apparatuses face challenges in positioning adjustments between primary and secondary mirrors, leading to light loss and production difficulties due to complex configurations and accuracy issues.
Innovation Solution
The alignment device employs a dichroic film on the secondary mirror's front surface and a back reflecting or refracting surface to transmit alignment light, allowing for position adjustments between primary and secondary mirrors without significant light loss, using a simple configuration that includes a light source, dichroic mirror, beam splitter, and photodetector to detect positional deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a spherical mirror of annular shape is used as a null optical system attached in close contact to the peripheral part of the secondary mirror, then alignment can be achieved, but production difficulty increases and center shielding of the beam increases
Solution Approach 1:
The patent extracts the alignment function from a separate null optical system and integrates it into the secondary mirror itself by forming a back reflecting surface directly on the secondary mirror. This eliminates the need for a separate spherical mirror component, thereby reducing production difficulty while maintaining alignment precision.
Solution Approach 2:
The patent merges the alignment function with the secondary mirror by integrating the back reflecting surface into the secondary mirror structure. This combination eliminates the need for separate alignment components and reduces center shielding area, as the alignment function is performed within the existing mirror geometry.
2Measurement precision
If a perforated plane mirror with large diameter and large center through hole is used, then alignment can be achieved, but light quantity is reduced and production accuracy becomes difficult
Solution Approach 1:
The patent extracts the alignment function from a large-diameter perforated mirror and relocates it to the secondary mirror's back surface. This eliminates the need for a large aperture in the primary mirror, thereby preserving light quantity while maintaining alignment precision through the back reflecting surface configuration.
Solution Approach 2:
The patent moves the alignment function from the primary mirror plane to the secondary mirror's back surface, utilizing a different spatial dimension. This allows alignment to be achieved without compromising the primary mirror's light-gathering area, as the alignment optics are now positioned in a different location within the optical path.
3Measurement precision
If a perforated plane mirror with large diameter is used, then alignment can be achieved, but positioning accuracy becomes difficult and cost increases
Solution Approach 1:
The patent extracts the alignment function from a large-diameter mirror that requires precise positioning and integrates it into the secondary mirror structure. The back reflecting surface is formed on the secondary mirror which is already precisely positioned in the optical system, thereby eliminating positioning accuracy challenges associated with large-diameter mirrors.
Solution Approach 2:
The secondary mirror serves multiple functions: it performs its primary optical function and simultaneously provides the back reflecting surface for alignment. This multi-functionality eliminates the need for a separate large-diameter alignment mirror, thereby avoiding the positioning accuracy and cost issues associated with such components.
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 solution enables precise position adjustment between primary and secondary mirrors in laser optical systems, such as Cassegrain and Gregorian systems, without substantial light loss, improving alignment accuracy and reducing production complexities.
Implementation Method 1
a dichroic film to reflect laser light used in the optical system and transmit alignment light
Implementation Method 2
a back reflecting surface to reflect the alignment light
Implementation Method 3
the position of the alignment light, and perform the position adjustment between the primary mirror and the secondary mirror based on the detected positional deviation information
Data Source
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AI summary
An alignment device is provided for aligning a primary mirror with a secondary mirror in an optical system having the primary mirror (21) and the secondary mirror (22) arranged so as to face each other along the optical axis (AX). The alignment device has a dichroic film (4) formed on a surface on the front side of the secondary mirror and configured to reflect light used in the optical system and to transmit alignment light, a back reflecting surface (5) formed on the back side of the secondary mirror and configured to reflect the alignment light, and a detection system (6, 7, 8) which detects a positional deviation between the primary mirror and the secondary mirror, based on the alignment light having traveled via the dichroic film (4), the back reflecting surface (5), and a reflecting surface of the primary mirror (21).