Automated Filter Changer for Dynamic Light Scattering
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Solution Overview
Problem
Current laboratory instruments for dynamic light scattering (DLS) are unable to perform depolarised dynamic light scattering (DDLS) measurements due to their inability to measure different polarisation states of scattered light, and upgrading or replacing these systems is expensive.
Innovation Solution
An instrument with an automated optical filter changer that includes a rotatable wheel with multiple filter mounts, allowing for the placement or removal of optical filters, such as polarising, fluorescence, band-stop, or band-pass filters, between the sample cell and scattered light detector, enabling the measurement of different polarisation states and reducing fluorescence interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If standard DLS measurements are performed without optical filters, then measurement simplicity is maintained, but fluorescence interference degrades measurement accuracy
Solution Approach 1:
The optical filter is made movable between different positions (in path and out of path) to dynamically adjust the measurement configuration. This allows the instrument to switch between fluorescence-rejection mode and standard DLS mode, resolving the contradiction by making the system adaptable rather than statically complex
Solution Approach 2:
The optical filter is extracted from the fixed measurement path and placed on a movable carrier. This extraction allows the filter to be removed from the path when not needed, eliminating unnecessary complexity while maintaining the capability to improve measurement accuracy when fluorescence interference is present
2Object-affected harmful factors
If a fluorescence filter is always placed in the detection path, then fluorescence interference is reduced, but DLS measurement quality degrades due to unnecessary filtering
Solution Approach 1:
The filter position is made dynamic rather than fixed, allowing the system to adapt to different measurement conditions. When fluorescence interference is present, the filter is positioned in the detection path; when it is absent, the filter is moved out of the path, thus eliminating harmful factors without compromising measurement quality
3Adaptability or versatility
If existing DLS instruments are used without modifications, then cost is reduced, but the ability to perform DDLS measurements is lost
Solution Approach 1:
The movable optical filter mechanism provides multi-functionality, enabling the existing DLS instrument to perform both standard DLS measurements and DDLS measurements. By adding this single versatile component, the instrument gains the ability to measure different polarisation states without requiring complete system replacement
Solution Approach 2:
The movable optical filter acts as an intermediary component that bridges the gap between standard DLS instrumentation and DDLS measurement capabilities. This intermediate addition allows polarisation-state discrimination without fundamentally altering the core instrument architecture
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
Enables the performance of DDLS and fluorescence correlation spectroscopy measurements using existing DLS instruments, improving measurement accuracy and flexibility by automating the filter changes, thus enhancing the characterisation of particles without the need for costly hardware upgrades.
Implementation Method 1
a filter changer positioned between the sample chamber and the scattered light detector. The filter changer comprises: at least one optical filter
Implementation Method 2
an actuator for moving the at least one optical filter between a first position in which the detection path does not pass through the optical filter, and a second position in which the detection path passes through the optical filter
Implementation Method 3
a scattered light detector positioned to receive scattered light along a detection path from a sample in the sample cell, the scattered light produced by the interaction of the light beam with the sample
Implementation Method 4
a light source operable to provide a light beam and defining an illumination axis
Implementation Method 5
The filter changer may comprise a rotatable wheel, the wheel comprising a plurality of filter mounts for holding a plurality of optical filters, and wherein the actuator is operable to rotate the wheel so as to move each filter between the first and second positions
Data Source
AI summary
An instrument and a method for measuring the characteristics of particles in a sample. The instrument comprises a light source operable to provide a light beam and defining an illumination axis; a sample cell placed on the illumination axis; a scattered light detector positioned to receive scattered light along a detection path from a sample in the sample cell, the scattered light produced by the interaction of the light beam with the sample; and a filter changer positioned between the sample cell and the scattered light detector. The filter changer comprises at least one optical filter and an actuator. The actuator is operable to move each of the at least one optical filter between a first position in which the detection path does not pass through the optical filter, and a second position in which the detection path passes through the optical filter.