Optical Delay Apparatus Using Misaligned Retroreflectors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing optical delay apparatuses face challenges in size reduction while maintaining or increasing optical path length, which is crucial for low-coherence interference measurement techniques used in medical devices like optical coherence tomography.
Innovation Solution
The optical delay apparatus employs a configuration of retroreflectors and a driving mechanism that allows for misalignment and relative movement between retroreflectors, enabling a significant change in optical path length with a compact design, doubling the path length change compared to conventional techniques while reducing the apparatus size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If conventional optical delay apparatus configurations are used, then the apparatus can provide sufficient optical path length, but the apparatus size becomes large
Solution Approach 1:
The patent introduces a lateral misalignment dimension between retroreflectors in addition to their positional arrangement. By misaligning retroreflectors laterally (perpendicular to the optical axis) and controlling their relative positions, the system achieves extended optical path length without proportionally increasing apparatus footprint. This dimensional approach allows light to traverse a longer path through multiple reflections while keeping the physical footprint compact.
Solution Approach 2:
The patent arranges multiple retroreflectors in a nested or folded configuration where light reflects between them in a compact spatial arrangement. The retroreflectors are positioned and misaligned to create a folded optical path that effectively 'nested' multiple reflection events within a reduced physical space, achieving longer optical path length within a smaller apparatus envelope.
2Area of stationary object
If the apparatus size is reduced, then the device becomes more compact, but the optical path length decreases
Solution Approach 1:
By utilizing lateral misalignment between retroreflectors perpendicular to the optical axis, the system decouples the relationship between apparatus size and optical path length. The misaligned retroreflectors create an extended effective path length through geometric arrangement in a different dimension, allowing compact apparatus size while maintaining sufficient optical path length for measurement.
Solution Approach 2:
The patent employs a driving mechanism that enables dynamic adjustment of the relative positions and misalignment between retroreflectors. This dynamic capability allows the system to optimize the optical path length for different measurement requirements while maintaining a compact apparatus size, providing flexibility without requiring a large fixed-size configuration.
3Length of stationary object
If misalignment between retroreflectors is introduced, then the optical path length increases significantly, but the alignment precision requirements increase
Solution Approach 1:
The retroreflectors are designed to automatically self-align or self-correct alignment errors through their reflective geometry. The retroreflector structure inherently returns light parallel to the incident direction regardless of minor angular deviations, providing self-aligning functionality that reduces the impact of manufacturing precision limitations and simplifies the alignment process.
Solution Approach 2:
The patent replaces complex mechanical alignment adjustment mechanisms with a driving mechanism that controls the relative positioning of misaligned retroreflectors. This substitution allows precise control of the optical path length through programmed positional changes rather than relying on manual mechanical alignment, reducing the practical impact of manufacturing tolerances through active 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
This configuration allows for a substantial increase in optical path length with a smaller apparatus size, enhancing the resolution and range of low-coherence interference measurements, particularly in optical coherence tomography applications.
Implementation Method 1
The first retroreflector includes a first reflection surface and a second reflection surface which are substantially perpendicular to each other. The second retroreflector includes a third reflection surface and a fourth reflection surface which are opposite to the first reflection surface and substantially perpendicular to each other.
Implementation Method 2
a first retroreflector, a second retroreflector, and a third retroreflector... The first retroreflector includes a first reflection surface and a second reflection surface which are substantially perpendicular to each other
Implementation Method 3
The first driving mechanism moves the first retroreflector and a set of the second retroreflector and the third retroreflector relative to each other
Implementation Method 4
Low-coherence interference measurement is a technique involving sufficient resolution to enable information such as the surface shape or thickness of a measurement target to be obtained at a scale almost equal to the wavelength of light
Data Source
AI summary
According to one embodiment, an optical delay apparatus includes the following elements. The first retroreflector includes a first and a second reflection surface. The second retroreflector includes a third and a fourth reflection surface opposite to the first reflection surface. The third retroreflector includes a fifth and a sixth reflection surface opposite to the second reflection surface. The first driving mechanism moves the first retroreflector and a set of the second retroreflector and the third retroreflector relative to each other. The second retroreflector and the third retroreflector are misaligned with each other in a direction along a first line of intersection between the first reflection surface and the second reflection surface.