Surgical Microscope Light Trap for Stray Light Elimination
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Solution Overview
Problem
Existing optical observation devices, such as surgical microscopes, face challenges in eliminating stray light when coupling an illumination beam path into an observation beam path using a beam splitter, as residual reflectance leads to disruptive light components entering the observation path, especially in high-intensity applications like surgical microscopes.
Innovation Solution
A specially designed light trap with a neutral filter element featuring a hollow radius light entry surface, which collimates and directs stray light to a non-interfering location, effectively preventing its entry into the observation path, and is optimized for use in various optical observation devices including surgical microscopes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a beam splitter is used to couple the illumination beam path into the observation beam path, then the illumination can be integrated into the observation system, but stray light is generated that reduces image contrast
Solution Approach 1:
The harmful stray light component is extracted and separated from the main beam path using the beam splitter's reflective property. The light trap is positioned to specifically capture and remove the transmitted illumination beam, isolating the harmful effect from the useful observation path.
Solution Approach 2:
The beam splitter's residual transmission, which initially creates harmful stray light, is converted into a beneficial feature by positioning the light trap to utilize this transmitted light for illumination purposes, thereby converting the harmful stray light into useful illumination for the observation path.
2Object-affected harmful factors
If a light trap is positioned next to the beam splitter to absorb non-reflected illumination light, then stray light is reduced, but the light trap cannot be used for incident light illumination in microscopes due to residual reflectance
Solution Approach 1:
The light trap is designed with spatially differentiated functionality: the first light trap handles transmitted illumination light absorption, while the second light trap specifically addresses reflected light from the objective lens. Each light trap is positioned and configured to address the specific local stray light problem in its region.
Solution Approach 2:
The solution extends from a single light trap configuration to a two-dimensional arrangement with light traps positioned in different spatial locations and orientations. The first light trap addresses the beam path direction, while the second light trap addresses the reflected light path from the objective lens, creating a comprehensive stray light elimination system.
3Illumination intensity
If high light intensity is used in surgical microscopy, then observation quality is improved, but residual reflectance from filter elements causes disruptive stray light
Solution Approach 1:
The light traps serve as intermediary elements between the high-intensity illumination source and the observation path. They intercept and absorb the stray light components that would otherwise be amplified by the high intensity and enter the observation path, thereby mediating between the need for high intensity and the need to eliminate stray light.
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
The light trap significantly reduces stray light, improving image contrast and usability in applications where residual reflectance is a concern, by collimating and absorbing stray illumination light, thus enhancing the performance of optical observation devices.
Implementation Method 1
The light trap is characterized, firstly, by the fact that the light-entry surface of the filter element has a hollow radius. This allows any false light to be eliminated in a particularly effective way
Implementation Method 2
The light trap's function is to absorb the non-reflected illumination light coming from the illumination device and passing through the beam splitter
Data Source
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AI summary
The present invention relates firstly to a light trap (20) for eliminating or preventing stray light, such as in the form of scattered light. Furthermore, the invention relates to a device (10) for coupling a first beam path (34) into a second beam path (42). Finally, the invention also relates to an illumination device (30) for an operating microscope and to an operating microscope itself. To further improve the elimination of interfering stray light in the form of scattered light, the light trap (20) is designed in a special way.This has a filter element (21), in particular a neutral density filter element, which is characterized in that the light entry surface (22) of the filter element (21) has a hollow radius, that the radius of curvature of the light entry surface (22) is in the range of 25 mm to 200 mm, preferably in the range of 45 mm to 110 mm, that the filter element (21) consists at least partially of an absorption material or that at least the light entry surface (22) is provided at least partially with an absorption material and that the filter element (21) has a high absorption coefficient of greater than or equal to 80%.