Eyepiece Device Thermal Expansion Management
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Solution Overview
Problem
Surgical endoscopes face challenges with chromatic aberration and temperature resistance, particularly during autoclaving, due to differences in thermal expansion coefficients of optical elements and the brittleness of anomalous dispersion lenses.
Innovation Solution
The ocular device for surgical instruments incorporates an optical unit with a first and second optical element, where the second element is made of a material with anomalous dispersion, and an expansion space in the eyepiece mount allows the second element to expand radially without mechanical stress, while the first element is mechanically connected to the mount.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an optical unit corrected for chromatic aberration is used with a second optical element made of material with anomalous dispersion, then chromatic aberration is reduced, but the brittleness of the second optical element increases and it becomes more sensitive to thermal expansion
Solution Approach 1:
The optical unit is segmented into a first optical element and a second optical element made of different materials. The second optical element with anomalous dispersion is separated from direct mechanical connection to the mount, allowing it to be isolated from thermal stress while maintaining its optical correction function
Solution Approach 2:
The first optical element acts as an intermediary between the eyepiece holder and the second optical element. It provides the mechanical connection to the mount while the second element remains mechanically decoupled, serving as a buffer that protects the brittle anomalous dispersion material from thermal stress
2Strength
If the second optical element is mechanically connected to the eyepiece holder, then the optical unit is securely mounted, but thermal expansion during autoclaving causes mechanical stress and potential damage
Solution Approach 1:
The second optical element is extracted from the direct mechanical mounting structure. It is positioned in the optical path without being rigidly attached to the eyepiece holder, allowing it to be removed from the system of parts subject to thermal expansion constraints
Solution Approach 2:
The mechanical connection parameters are changed by introducing selective attachment: the first optical element is rigidly mounted to the holder while the second element is optically coupled but mechanically decoupled, changing the boundary conditions from fully constrained to partially free
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 design enhances temperature resistance and prevents damage to the optical unit during autoclaving by isolating the more brittle second optical element from mechanical stress, ensuring the ocular device's durability and functionality.
Implementation Method 1
the second optical element is made of a second material with anomalous dispersion, and the first and the second optical elements together form an optical unit corrected with respect to chromatic aberration
Implementation Method 2
This arises from the dispersion of optical glass, as light of different wavelengths is refracted to varying degrees
Implementation Method 3
The materials used to correct chromatic aberrations, for example glasses with anomalous dispersion, expand more when heated than glasses with normal dispersion
Data Source
Figure 1
Figure 2~3
AI summary
The invention relates to an eyepiece device (20), an eyepiece (44) and a surgical instrument (2), wherein the eyepiece device (20) for a surgical instrument (2) comprises an eyepiece frame (22) and at least one optical unit (24), wherein the optical unit (24) is accommodated in the eyepiece frame (22). The optical unit (24) comprises a first optical element (26) and a second optical element (28) connected therewith, wherein the optical elements (26, 28) form an optical unit (24) which is corrected in respect of chromatic aberration and the second optical element (28) is produced from a material with abnormal dispersion. The eyepiece device (20) is developed by virtue of there being at least one mechanical connection element (30) between the eyepiece frame (22) and the first optical element (26) for accommodating the optical unit (24) in the eyepiece frame (22).