Optical Isolator Layout for Stable Platelet Signal Detection
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Solution Overview
Problem
Existing optical detection systems in blood cell analyzers face instability due to reflected light, leading to amplitude changes and frequency shifts in laser beams, which confuse small pulses from interfering sources with those from platelet particles, hindering accurate platelet detection.
Innovation Solution
An optical detection system with an optical isolator comprising a beam splitter prism and polarization conversion elements to isolate reflected light, combined with a frequency-doubling crystal and bandpass filter, ensures stable laser output and precise platelet detection by isolating and filtering out interfering light pulses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pulse detection threshold value is set to be greater than the amplitudes of interfering small pulses to filter them out, then the stability of laser output is improved, but the measurement precision of platelet detection deteriorates
Solution Approach 1:
The patent extracts and removes the interfering reflected light from the optical path by introducing an optical isolator. This isolator specifically blocks the reflected light while allowing the forward propagating laser beam to pass through, thereby eliminating the source of interfering small pulses without affecting the detection of genuine platelet signals
Solution Approach 2:
The optical isolator acts as an intermediary component in the optical path. It is positioned between the laser and the detection system to selectively block reflected light while transmitting the useful laser beam, thus mediating between the laser source and the detection system to prevent interference without compromising detection capability
2Object-affected harmful factors
If the detection threshold is increased to eliminate interfering pulses, then the harmful factors affecting the system are reduced, but the detection precision of small platelet signals deteriorates
Solution Approach 1:
The patent converts the harmful reflected light into a beneficial situation by using the optical isolator to block it. The reflected light that would otherwise create interfering pulses is now prevented from re-entering the laser cavity, transforming a harmful factor into a non-issue while preserving all detection capabilities
Solution Approach 2:
The optical isolator serves as an intermediary that selectively removes the harmful reflected light component from the optical path while leaving the useful forward propagating beam intact, thus eliminating interference without affecting the detection of genuine platelet signals
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 system effectively isolates reflected light, stabilizes laser output, and improves detection precision by distinguishing between interfering pulses and genuine platelet signals, enhancing the accuracy of platelet detection in blood cell analysis.
Implementation Method 1
The optical isolator comprises a beam splitter prism and polarization conversion element which are adhesively connected with each other. The beam splitter prism is configured to reflect the S-polarization component of the incident laser beam and transmit the P-polarization component of the incident laser beam. The polarization conversion element is configured to change the polarization state of the P-polarization component transmitted through the beam splitter prism such that the P-polarization component is changed from linearly polarized light into circularly polarized light
Implementation Method 2
The beam splitter prism is configured to reflect the S-polarization component of the incident laser beam
Implementation Method 3
The bandpass filter is configured to transmit the laser beam with a wavelength of 630 nm to 640 nm
Implementation Method 4
The frequency-doubling crystal is configured to perform frequency doubling on the laser beam passing through the bandpass filter and perform frequency doubling again on reflected light of the frequency-doubled laser beam
Implementation Method 5
the front optical assembly is configured to perform front optical treatment on the laser beam, such that the laser beam subjected to the front optical treatment is converged in a first direction at the platelet particles in the flow chamber, and scattered light is thus generated
Data Source
AI summary
An optical detection system, a blood cell analyzer and a platelet detection method are provided. The optical detection system includes: an optical subsystem, a flow chamber and a first detector; the optical subsystem includes a laser, a front optical assembly including an optical isolator, and a rear optical assembly including a blocking diaphragm. The laser is configured to emit a laser beam; the front optical assembly is configured to perform front optical treatment; the rear optical assembly is disposed downstream of the flow chamber in the propagation direction of the laser beam, and is configured to perform rear optical treatment on the scattered light and the laser beam converged at the blocking diaphragm; and the optical isolator is configured to isolate reflected light that is generated when the laser beam passes through the flow chamber.