OCT Reference Reflector Actuator for Wide Field-of-View Imaging
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Solution Overview
Problem
Conventional Optical Coherence Tomography (OCT) systems face challenges in providing wide-field-of-view imaging across curved surfaces, such as the retina, especially in highly myopic patients, due to image distortion caused by variations in optical path length differences.
Innovation Solution
The OCT system employs a linear actuator, such as a piezoelectric or voice coil actuator, to dynamically adjust the reference reflector's position, synchronizing with the scanner's scan rate, to maintain the reference beam path length within a tolerance range matching the imaging beam path length across varying scan angles, thereby reducing distortion and maintaining image clarity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the scan angle is increased to achieve wide field-of-view imaging, then the imaging coverage area is improved, but the image distortion increases due to optical path length differences
Solution Approach 1:
The reference mirror is made movable via a linear actuator to dynamically adjust the reference beam path length in real-time during scanning. This dynamic adjustment compensates for the varying optical path length differences that occur at different scan angles, thereby maintaining image quality across the wide field of view without sacrificing imaging coverage area
Solution Approach 2:
The system changes the path length parameter of the reference beam dynamically during operation. By adjusting the reference mirror position through the linear actuator, the reference path length is modified to match the sample path length at each scan angle, compensating for distortion while preserving the wide imaging area
2Manufacturing precision
If the reference beam path length is adjusted to compensate for scan angle variations, then the image distortion is reduced, but the system complexity increases
Solution Approach 1:
The patent replaces complex optical mechanical systems with a simpler linear actuator mechanism to adjust the reference mirror position. This substitution achieves the necessary path length compensation with a more straightforward mechanical solution, reducing overall system complexity while maintaining image quality
Solution Approach 2:
The linear actuator serves as an intermediary component between the control system and the reference mirror. It provides a simple mechanical interface to achieve precise path length adjustment, simplifying the control architecture while effectively compensating for scan angle variations
3Measurement precision
If the linear actuator translates the reference reflector to maintain path length, then the path length matching precision is improved, but the device complexity increases
Solution Approach 1:
The linear actuator is configured to automatically adjust the reference mirror position based on real-time scan angle information. The system self-regulates the path length matching without requiring complex external intervention, achieving high precision while keeping the control mechanism relatively simple through automated feedback
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 approach enables ultra-wide field-of-view OCT imaging with reduced distortion, ensuring that the target surface remains centered throughout the image window, even on curved surfaces like high-myopia retinal surfaces, facilitating improved live imaging during surgical procedures.
Implementation Method 1
The linear actuator comprises a piezoelectric stack configured to translate the reference reflector at least 2mm in a direction parallel to the reference beam
Implementation Method 2
The linear actuator comprises a voice coil configured to translate the reference reflector at least 2mm in a direction parallel to the reference beam
Implementation Method 3
a beam splitter, configured to split the OCT beam into a reference beam and an imaging beam, direct the reference beam toward a reference reflector, and direct the imaging beam toward a scanner
Implementation Method 4
a detector configured to receive the reference beam reflected by the reference reflector and the imaging beam reflected by the target surface, and output an interference signal based on the received reference beam and the imaging beam
Implementation Method 5
the scanner, configured to scan the imaging beam onto a target surface over a plurality of scan angles
Data Source
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AI summary
An optical coherence tomography (OCT) system includes a light source configured to generate an OCT beam and a beam splitter, configured to split the OCT beam into a reference beam and an imaging beam, direct the reference beam toward a reflector, and direct the imaging beam toward a scanner. The system includes a linear actuator, such as a piezoelectric or voice coil, configured to move the reflector to adjust the length of the reference beam and the scanner, configured to scan the imaging beam onto a target surface at a plurality of scan angles, wherein the scanner and target surface are separated by a sample distance that varies at each of the scan angles. The system further includes an OCT controller comprising a processor and instructions stored on a memory, the instructions executable by the processor to cause the OCT controller to generate signals to cause the scanner to scan the imaging beam at each of the scan angles at a first scan rate, and cause the actuator to adjust the length of the reference beam during the scan synchronously with the scan rate to offset the variation in sample distance at each of the scan angles.