Image Reversing System Stray Light Suppression
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Solution Overview
Problem
The existing image inversion systems in terrestrial telescopes suffer from unwanted brightening and color errors due to stray light reaching the viewer's eye directly from the lens through the roof prism and eyepiece, without being shadowed by other apertures, leading to image disturbances.
Innovation Solution
Incorporating a first diaphragm to delimit the imaging rays and suppress interfering light, followed by a second aperture and an additional screen at the narrowest constriction to block stray light, ensuring only necessary rays for geometric-optical imaging enter the system, with the additional screen being oval-arc shaped and aligned perpendicularly to the plane mirror surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If circular screens are installed in front of and behind the reversing system and in front of and behind the prism entry and exit surfaces, then light rays entering from outside the recording angle are suppressed, but stray light can still reach the viewer's eye directly from the lens through the roof prism and eyepiece without touching the plane mirror
Solution Approach 1:
The patent divides the aperture system into multiple segments: a first aperture (4) at the object side, a second aperture (9) at the image side, and an additional screen (12) at the narrowest constriction (10). Each aperture serves a specific function in blocking stray light from different directions, collectively achieving complete suppression of false light that cannot be accomplished by a single circular screen.
Solution Approach 2:
The patent introduces an additional dimension of light blocking by placing the additional screen (12) at the narrowest constriction (10) where the beam cross-section is smallest. This creates a critical blocking point that prevents stray light from bypassing the plane mirror, adding a new spatial dimension to the aperture system's stray light suppression capability.
2Object-affected harmful factors
If the additional screen is placed at the narrowest constriction with an opening adapted to the diameter of the intersecting bundles of rays, then stray light is effectively blocked, but the device complexity increases due to the additional screen and its precise alignment requirements
Solution Approach 1:
The additional screen (12) is positioned at the narrowest constriction (10) where the light bundles intersect, which is the most critical point for blocking stray light. By placing the screen at this predetermined location with an opening adapted to the diameter of the intersecting bundles, the system achieves maximum blocking efficiency with minimal additional complexity.
Solution Approach 2:
The additional screen (12) serves multiple functions simultaneously: it blocks stray light from entering the intermediate image plane, defines the effective aperture for the imaging beam, and provides a reference alignment surface for ensuring proper orientation of the optical components. This multi-functionality reduces the need for separate alignment fixtures.
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
Effectively prevents stray light from entering the intermediate image plane, thereby eliminating unwanted brightening and color errors, enhancing the clarity and accuracy of the viewed image.
Implementation Method 1
The surface of the plane mirror 1 is illuminated by a bundle of rays 3... The beam of rays 3 incident on the plane mirror 1 and the beam of rays 3 reflected thereon intersect
Implementation Method 2
The light beam reflected at the plane mirror enters the base surface of a roof prism... and is reflected on the roof surfaces in an image-reversing manner
Implementation Method 3
In the direction of light in front of the eyepiece, the lens produces a right-sided, but upside-down intermediate image of an object
Data Source
Figure 1~2
AI summary
The system has a plane mirror (1) and a roof edge prism (5) arranged in a light direction, where the plane mirror is inclined in an image beam path. A diaphragm (12) is arranged on the plane mirror enclosing light beams (3), where the diaphragm is arranged in the image beam path at a region of intersection of an incident light beam and a reflected light beam. Another diaphragm (4) is arranged in front of the plane mirror and perpendicular to an optical axis (2) for limiting an object image forming light beam. The former diaphragm is vertically arranged on a plane mirror surface.