Oblique OCT Light Detection Module Reducing Fixed Pattern Noise
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional OCT instruments fail to sufficiently reduce fixed pattern noise, which appears as non-existent images at specific positions in the depth direction of tomographic images due to multiple reflections of interference light in the optical lens.
Innovation Solution
A light detecting module for OCT instruments is designed with an optical lens and photodetector configuration where the interference light enters and exits obliquely, preventing multiple reflections between the optical fiber exit end surface and the photodetector, and optionally includes a cover part to filter out non-interference light, ensuring the optical lens positions are defined.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional OCT instruments use standard optical lens configuration, then the device structure is simple, but fixed pattern noise appears due to multiple reflections of interference light
Solution Approach 1:
The patent applies asymmetry by tilting the incident surface and exit surface of the optical lens at specific angles (e.g., 5-15 degrees) relative to the optical axis. This asymmetric configuration prevents parallel multiple reflections of interference light between the lens surfaces, thereby reducing fixed pattern noise while maintaining manufacturability
Solution Approach 2:
The patent changes the geometric parameters of the optical lens, specifically the tilt angles of the incident and exit surfaces. By adjusting these angular parameters, the optical path of reflected light is modified to prevent constructive interference that causes fixed pattern noise, while keeping the overall device structure relatively simple
2Object-affected harmful factors
If the incident surface and exit surface are disposed obliquely to prevent multiple reflections, then fixed pattern noise is reduced, but the alignment precision required increases
Solution Approach 1:
The patent incorporates preliminary action by providing a mounting structure that pre-defines the tilted angles of the incident and exit surfaces during assembly. This pre-positioning approach ensures that the precise angular alignment is achieved during manufacturing without requiring complex real-time adjustment, thus reducing the actual alignment precision burden during operation
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 effectively reduces fixed pattern noise, improving the quality of tomographic images by preventing multiple reflections and minimizing noise from non-interference light.
Implementation Method 1
The incident surface is disposed in such a manner that the interference light obliquely enters with respect to a perpendicular line at an incident position of the interference light. The exit surface is disposed in such a manner that the interference light obliquely exits with respect to a perpendicular line at an exit position of the interference light.
Implementation Method 2
The light detecting module for an OCT instrument includes an optical lens and a photodetector... The interference light that has exited the exit surface enters the detecting surface.
Data Source
AI summary
A light detecting module that detects interference light that has exited an exit end surface of an optical fiber in an OCT instrument includes: a ball lens including an incident surface entered by the interference light that has exited the exit end surface, and an exit surface exited by the interference light that has entered the incident surface; and a photodiode including a detecting surface entered by the interference light that has exited the exit surface. The interference light obliquely enters the incident surface with respect to a perpendicular line at an incident position of the interference light. The interference light obliquely exits the exit surface with respect to a perpendicular line at an exit position of the interference light. The interference light obliquely enters the detecting surface with respect to a perpendicular line at an incident position of the interference light.