Spectral OCT Alignment Correction via Calibration Light
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Solution Overview
Problem
Existing optical coherence tomography (OCT) systems based on spectral interference face challenges in accurately obtaining depth direction information due to misalignment between optical members and photodetectors, leading to inaccurate spectral information detection.
Innovation Solution
An OCT apparatus that includes an interference optical system, a spectral optical system, a photodetector, light guiding means for calibration light, and storage means for reference spectral information, with adjustment means to correct alignment between the spectral optical system and photodetector based on comparison between detected and stored spectral information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a predetermined correlation is established between photodetector pixels and frequency components, then spectral information can be detected, but misalignment between optical members and photodetector causes inaccurate spectral information detection
Solution Approach 1:
The patent applies preliminary action by performing alignment adjustment before actual measurement. The system uses calibration light to pre-adjust the alignment between the spectral optical system and photodetector, storing reference spectral information. This preliminary alignment ensures that when actual measurement occurs, the system is already in the correct state, preventing misalignment errors without affecting subsequent measurement reliability.
2Measurement precision
If alignment adjustment is performed using calibration light and reference spectral information, then accurate alignment can be achieved, but additional components and procedures are required
Solution Approach 1:
The patent applies universality by making the spectral optical system and photodetector serve dual functions: they can process both calibration light for alignment adjustment and measurement light for actual depth information acquisition. The same optical components and detector are used in both calibration and measurement modes, eliminating the need for separate dedicated calibration components and reducing overall system complexity.
Solution Approach 2:
The system applies self-service by using its own spectral optical system and photodetector to perform alignment calibration without requiring external specialized equipment. The calibration light passes through the same optical path and is detected by the same components that will be used for measurement, allowing the system to self-calibrate and maintain accuracy without adding complex external alignment tools.
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
Ensures accurate alignment between the spectral optical system and photodetector, thereby enhancing the precision of depth direction information acquisition in OCT systems, particularly in ophthalmic applications.
Implementation Method 1
synthesizing the measurement light reflected from the object and reference light being low coherent light to interfere by an interference optical system
Implementation Method 2
dispersing interference light for every frequency (wavelength) by a spectral optical system
Implementation Method 3
photo-receiving the dispersed interference light with a photodetector
Data Source
AI summary
An apparatus using optical coherence tomography based on spectral interference and an ophthalmic apparatus, which can accurately obtain information on an object in a depth direction by correcting misalignment between an optical member of a spectral optical system and a photodetector, includes an interference optical system for irradiating measurement light being low coherent light onto the object and synthesizing the measurement light reflected from the object and reference light being low coherent light to interfere, a spectral optical system which disperses interference light for every frequency, a photodetector photo-receiving the dispersed interference light, means guiding calibration light for adjusting alignment between the spectral optical system and the photodetector to the spectral optical system, means storing reference spectral information, and means adjusting the alignment based on a comparison between spectral information on the calibration light guided to the spectral optical system and photo-received on the photodetector, and the stored information.