Vertical Interface Detection Using Dual-Wavelength Laser Calibration
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Solution Overview
Problem
Existing apparatus for determining the vertical position of interfaces between components in a sample container face challenges such as cumbersome calibration of laser diodes with respect to the z-axis movement, degradation of the driving unit, and inability to detect deviations or state changes of the laser diodes over time.
Innovation Solution
An apparatus with a calibration device comprising bars and openings, allowing for precise calibration and periodic re-calibration of laser diodes with the z-axis movement, monitoring the state of the driving unit and laser diodes through periodic re-calibration data, and using wavelength-specific collimating optics to enhance detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If laser diodes are used for interface detection, then detection precision is improved, but calibration with respect to z-axis movement becomes cumbersome and reliability deteriorates
Solution Approach 1:
A calibration device with known geometric structure serves as an intermediary between the laser diodes and the z-axis movement system. This calibration device provides reference features that mediate the calibration process, making it systematic and reliable rather than cumbersome. The calibration device translates the complex calibration problem into measurable geometric relationships.
Solution Approach 2:
The system changes the calibration parameters by using multiple wavelengths of light from different laser diodes. By varying the wavelength parameter and measuring how different wavelengths interact with the calibration device and sample components, the system establishes reliable calibration data for z-axis movement compensation.
2Productivity
If the driving unit moves the sensing units, then productivity is improved, but the drive degrades over time and measurement precision deteriorates
Solution Approach 1:
The system implements feedback by continuously monitoring the actual position of the driving unit using the calibration device during periodic re-calibrations. This feedback information about drive degradation is used to compensate for position errors and maintain measurement precision despite wear over time.
Solution Approach 2:
The system performs preliminary calibration actions by establishing a reference calibration state before normal operation. Periodic re-calibrations are performed in advance to detect and correct drive degradation before it significantly impacts measurement precision, maintaining accuracy throughout the system's operational life.
3Measurement precision
If multiple sensing units are used, then detection precision is improved, but device complexity increases
Solution Approach 1:
The calibration device serves multiple functions: it calibrates the laser diodes, provides reference features for position measurement, and enables periodic re-calibration. This multi-functional approach consolidates several needs into a single device, reducing overall system complexity while maintaining high measurement precision through the use of multiple sensing units.
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 solution enables accurate and continuous monitoring of the vertical position of interfaces, maintains the health of the driving unit and laser diodes, and improves detection performance by reducing the impact of label layers on the sample container.
Implementation Method 1
a first laser diode configured to emit light having a first wavelength, which is substantially transmitted by the sample container and the first component
Implementation Method 2
a second laser diode configured to emit light having a second wavelength, which is substantially transmitted by the sample container but blocked by the first component
Implementation Method 3
a first collimating optics adapted to collimate the light having the first wavelength, a second collimating optics adapted to collimate the light having the second wavelength
Implementation Method 4
a first light detector configured to generate a first sensing signal in response to an intensity of light having the first wavelength being applied to the first light detector, a second light detector configured to generate a second sensing signal in response to an intensity of light having the second wavelength being applied to the second light detector
Data Source
Figure 1
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Figure 4
AI summary
An apparatus (100) for determining a vertical position of at least one interface (102) between a first component (104) and at least one second component (106), the components (104, 106) being comprised as different layers in a sample container (108), is disclosed. The apparatus (100) comprises a first sensing unit (116) comprising a first laser diode (118) configured to emit light having a first wavelength and a first light detector (122) configured to generate a first sensing signal (124) in response to an intensity of light having the first wavelength being applied to the first light detector (122). The apparatus (100) comprises a second sensing unit (126) vertically spaced by a given vertical distance (128) from the first sensing unit (116) and comprising a second laser diode (130) configured to emit light having a second wavelength and a second light detector (134) configured to generate a second sensing signal (136) in response to an intensity of light having the second wavelength being applied to the second light detector (134). The apparatus (100) comprises a driving unit (142) configured to move the sample container (108) relative to the first sensing unit (116) and the second sensing unit (126). The apparatus (100) comprises a position sensing unit (146) configured to output a position sensing signal (152) indicative of a vertical position of the sample container (108). The apparatus (100) comprises a vertical position determining unit (154) configured to match the first sensing signal (124) and the second sensing signal (136) such that first sensing signal (124) and the second sensing signal (136) correspond to identical vertical positions, and to determine the vertical position of the at least one interface (102) in response to the matched sensing signals (156) and the position sensing signal (152). The apparatus (100) comprises a calibration device (160) comprising a plurality of bars (162) and a plurality of openings (164) arranged between the bars (162). The driving unit (142) is configured to move the calibration device (160) relative to the first sensing unit (116) and the second sensing unit (126). The vertical position determining unit (154) is configured to determine a vertical orientation of the driving unit (142) relative to the first sensing unit (116) and the second sensing unit (126) based on the first and second signals (124, 136) generated during a movement of the calibration device (160) relative to the first sensing unit (116) and the second sensing unit (126).