OCT Test Object Lens Entry Surface for Signal Oversaturation
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Solution Overview
Problem
Current methods for testing OCT devices are labor-intensive and often result in oversaturation of the interference signal due to increased signal strength, which requires reducing the intensity of the OCT light, thereby altering measurement conditions from normal OCT measurements.
Innovation Solution
A method using a test object with a layered structure made of transparent materials, where the entry surface is shaped as a lens surface, allowing for controlled index of refraction jumps and avoiding oversaturation, enabling precise positioning of the focus within the test object to match the axial resolution of the OCT device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a test object is introduced into the object beam path to determine OCT parameters, then measurement capability is improved, but the signal strength increases causing oversaturation of the interference signal
Solution Approach 1:
A test object with controlled refractive index layers is introduced as an intermediary between the OCT beam path and the measurement system. The test object comprises multiple layers with gradually changing refractive indices, which mediate the interaction between the OCT light and the measurement system to prevent oversaturation while enabling accurate parameter determination.
Solution Approach 2:
The test object utilizes controlled changes in refractive index parameters across its layers. By designing layers with specific refractive index values and transitions, the system modifies the optical parameters to achieve appropriate signal strength levels that prevent oversaturation while maintaining measurement accuracy for OCT device characterization.
2Object-affected harmful factors
If the intensity of OCT light is reduced to avoid oversaturation, then signal oversaturation is prevented, but the measurement conditions differ from normal OCT measurements
Solution Approach 1:
The test object acts as an intermediary that allows normal OCT light intensity to be used while preventing oversaturation. The controlled refractive index layers in the test object manage the signal strength internally, enabling measurements to proceed under normal operating conditions without requiring external intensity reduction.
Solution Approach 2:
The test object is self-regulating in terms of signal management. Its layered structure with specific refractive indices automatically controls the signal strength to prevent oversaturation without requiring external intervention or modification of the OCT system's operating parameters, thus maintaining measurement condition consistency.
3Ease of operation
If the focus position is not precisely controlled in the test object, then alignment is simpler, but the determination of focus position and lateral resolution becomes inaccurate
Solution Approach 1:
The test object utilizes optical path length changes that manifest as detectable signal variations, analogous to color changes in visual detection. By monitoring the interference signal characteristics as the test object is moved axially, the focus position can be precisely identified through signal maxima detection, providing both ease of operation and high measurement precision.
Solution Approach 2:
The measurement system incorporates feedback through detection of interference signal maxima. As the test object is positioned axially, the system monitors the signal strength and identifies the focus position when the signal reaches its maximum value, providing automatic feedback that ensures precise focus determination without complex alignment procedures.
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 allows for accurate determination of OCT device parameters like numerical aperture, focus position, and lateral resolution without oversaturation, providing improved resolution and insensitivity to alignment errors, while maintaining conditions similar to normal OCT measurements.
Implementation Method 1
the index of refraction jumps can be kept small at the interfaces, from which the interference signal is obtained
Implementation Method 2
components of the object beam path reflected from the object are superimposed with a reference beam path to generate an interference signal
Implementation Method 3
The focus of the object beam path can be positioned in a suitable manner by the entry surface of the entry body shaped as a lens surface
Implementation Method 4
An entry surface of the entry body is shaped as a lens surface
Data Source
AI summary
A method for testing an OCT device (14), in which a first test object (27) is arranged in an OCT beam path (16) of an OCT device (14). The first test object (27) comprises a layered structure (29) made up of a plurality of transparent layers and an entry body (30). OCT light emitted by the OCT device (14) enters the entry body (30) via an entry surface and propagates through the entry body (30) up to the layered structure (29). An entry surface of the entry body (30) is shaped as a lens surface (31). The invention also relates to a test object (27), which can be used in such a method.