Ophthalmic Surgical System Beam Splitter Polarization
Solution Overview
Problem
Ophthalmic surgical systems with wavefront sensors experience inefficiencies in detecting measuring light, particularly due to insufficient separation and polarization management of beam paths.
Innovation Solution
The system employs two beam splitters, a dichroic and a polarizing beam splitter, along with a retarding plate made of birefringent material, to optimize beam paths by separating wavelengths and polarizations, ensuring high-efficiency detection of measuring light through the use of dichroic and polarizing beam splitters and a retarding plate that introduces specific phase differences and orientations to enhance light polarization states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a single polarizing beam splitter is used to separate measuring light, then the beam path separation is achieved, but the detection efficiency of measuring light is insufficient
Solution Approach 1:
The patent divides the beam path separation function into two distinct beam splitters: a dichroic beam splitter that separates wavelengths and a polarizing beam splitter that separates polarizations. This segmentation allows each component to specialize in one separation task, thereby maximizing the intensity of measuring light reaching the detector while maintaining manageable system complexity through functional decomposition.
Solution Approach 2:
The dichroic beam splitter acts as an intermediary element between the light source and the polarizing beam splitter. It first separates the measuring light wavelength from other wavelengths, then passes it to the polarizing beam splitter for polarization separation. This intermediary role ensures that only the relevant measuring light reaches the polarizing beam splitter, improving overall detection efficiency.
2Loss of energy
If measuring light is transformed into circularly polarized light using a quarter-wave plate, then the light returns with orthogonal linear polarization, but the detection efficiency remains insufficient due to polarization misalignment
Solution Approach 1:
The patent modifies the polarization state parameters by introducing a retarding plate with a specific fast axis orientation (at an angle α between 0° and 45° relative to the s-polarization direction). This parameter change transforms the returning circularly polarized light into linearly polarized light with a controlled polarization direction that optimally aligns with the polarizing beam splitter's transmission axis, maximizing light intensity at the detector while preserving wavefront information.
3Productivity
If the fast axis of the retarding plate is oriented at 45° to the s-polarization direction, then circular polarization is achieved, but detection efficiency is reduced
Solution Approach 1:
The patent deviates from the conventional 45° orientation by setting the fast axis angle α to a specific range (0° < α < 45°). This parameter optimization balances two requirements: it creates sufficient elliptical/circular polarization for the round trip through the eye while ensuring that the returning light's linear polarization component aligns optimally with the detector's acceptance angle, thereby maximizing detection efficiency.
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 configuration significantly increases the efficiency of measuring light detection, allowing more light to reach the analyzing detector with high intensity, thereby improving the accuracy of wavefront analysis and refractive error detection in ophthalmic surgeries.
Implementation Method 1
The dichroic beam splitter is designed to separate two beam paths depending on the wavelength of the light of the respective beam path. Thereby, for example, light of a first wavelength traverses the dichroic beam splitter and light of a second wavelength is reflected at the dichroic beam splitter.
Implementation Method 2
The polarizing beam splitter is designed such that two beam paths are separated depending on a direction of polarization of the light of the respective beam path. Thereby, for example, light, which has a direction of polarization in a first direction linearly traverses the beam splitter, whereas light having a direction of polarization, which is oriented orthogonally relative to the first direction, is reflected at the polarizing beam splitter.
Implementation Method 3
The measuring light, which is traveling to the object, is linearly polarized after having passed the polarizing beam splitter and may be influenced with respect to the state of polarization by a retarding plate, which is arranged between the polarizing beam splitter and the object. Thereby, the measuring light, which is incident on the object, is circularly or elliptically polarized.
Data Source
AI summary
A system includes an optical system having two beam splitters (a dichroic beam splitter and a polarizing beam splitter), which are designed to provide three separate beam paths for observing an object. The dichroic beam splitter is designed to separate two beam paths depending on the wavelength of the light of the respective beam path. The polarizing beam splitter is designed such that two beam paths are separated depending on a direction of polarization of the light of the respective beam path. The measuring light is linearly polarized after having passed the polarizing beam splitter and may be influenced with respect to the state of polarization by a retarding plate. The returning measuring light incident on the polarizing beam splitter is linearly polarized and also polarized in such a direction that the returning measuring light is transported through the polarizing beam splitter towards the analyzing detector with a high efficiency.