Dual-Shielding Optical Attenuator for OCT Light Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional optical attenuators in OCT systems face challenges in precisely adjusting light amounts due to time degradation and environmental variations, requiring complex and costly mechanisms for accurate control, especially when shielding a large portion of light.
Innovation Solution
An optical image measurement apparatus with a dual-shielding optical attenuator system, utilizing a stepping motor and cam mechanism to adjust light amounts by shielding from two directions, allowing precise control without the need for high-resolution motors, using a cam face shaped according to light distribution for efficient light management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional single-shield optical attenuator is used, then the structure is simple, but the light amount adjustment precision is insufficient when shielding a large portion of light
Solution Approach 1:
The optical attenuator is divided into two independent shielding mechanisms: a first shield that rotates about a first axis and a second shield that rotates about a second axis. Each shield independently controls light blocking from different directions, allowing precise adjustment of the light amount by combining their effects without requiring a single complex high-resolution mechanism
Solution Approach 2:
The patent transitions from single-direction shielding to two-directional shielding by introducing shields rotating about different axes. This dimensional expansion allows the system to control light amount more precisely by blocking light from multiple angles simultaneously, effectively increasing the control degrees of freedom
2Measurement precision
If a high-resolution stepping motor is used for precise light amount control, then the operational accuracy is high, but the device complexity and cost increase
Solution Approach 1:
The rotational control is segmented into two independent axes, each driven by its own shielding mechanism. This allows the use of simpler rotation control for each axis while achieving high overall precision through the combined effect of both shields, avoiding the need for a single high-resolution motor
Solution Approach 2:
The patent introduces a light amount distribution calculation mechanism that acts as an intermediary between the simple rotation controls and the final light amount output. This calculation mechanism (using Gaussian distribution or other models) translates the simple rotational positions into precise light amount control, mediating between simple mechanics and precise optical control
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 dual-shielding system enables precise adjustment of light amounts, improving operational accuracy and reducing complexity and cost, allowing for suitable detection of interference light and high-definition imaging in OCT applications.
Implementation Method 1
a cam that has a cam surface shaped depending on the distribution of the light amount in the cross-section of the subject light, and that is rotated by the stepping motor
Implementation Method 2
a first shield that is provided at a predefined distance away from the axis of rotation and capable of shielding the subject light from a first direction; and a second shield that is capable of shielding the subject light from a second direction
Implementation Method 3
generates and detects interference light by superposing the signal light that has passed through a signal optical path toward a measured object and the reference light that has passed through a reference optical path
Data Source
AI summary
A cam face 303a of a cam 303 has a shape depending on the distribution of the light amount in the cross-section of reference light LR. When the cam 303 is rotated by a stepping motor 302, an abutment 312 moves following the displacement of the cam face 302a with the rotation of the cam 303. A light-blocking link 310 rotates about the axis of rotation 311 with the movement of the abutment 312. A shield 313 moves in a first direction with the rotation of the light-blocking link 310 to change the shielding region of the reference light LR. A light-blocking plate 400 can shield the reference light LR from a second direction different from a shielding direction (first direction) by an attenuator 300. The light-blocking plate 400 is moved by a drive mechanism 410 and changes the shielding region.