Mass Spectrometer Separated Optical Axes Design
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Solution Overview
Problem
Conventional mass spectrometers using LDI/MALDI techniques face limitations in spatial resolution and ion transport efficiency due to large laser light convergence diameters and overlapping optical systems, which hinder analysis of micro-sized samples like living cells.
Innovation Solution
A mass spectrometer design with separated optical axes for sample observation and laser delivery systems, allowing for reduced working distances and increased numerical apertures, enabling high spatial resolution and efficient ion transport without interfering with ion flight paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the laser-condensing optical system and observation optical system share the same optical axis, then the device structure is simplified, but the spatial resolution deteriorates due to large working distance and the ion transport efficiency deteriorates due to interference with ion flight paths
Solution Approach 1:
The patent divides the optical system into two separate systems: a laser-condensing optical system for delivering laser light to the sample, and an observation optical system for imaging the sample. These systems are spatially separated with different optical axes, allowing each to be optimized independently for its specific function without compromising the other's performance.
Solution Approach 2:
The patent transitions from a one-dimensional shared optical axis arrangement to a three-dimensional separated arrangement. The laser optical axis and observation optical axis are positioned at different spatial locations and angles, enabling both systems to operate simultaneously without interference while achieving small working distances for high spatial resolution.
2Measurement precision
If the laser light convergence diameter is reduced to improve spatial resolution, then the spatial resolution improves, but the ion-generating efficiency deteriorates
Solution Approach 1:
The patent applies different quality requirements to different regions of the laser beam. The central region of the laser spot is optimized for high intensity to generate sufficient ions, while the overall spot size is kept small for high spatial resolution. The observation system captures the entire irradiation area to ensure all ion-generating regions are detected.
3Measurement precision
If the working distance of the observation optical system is reduced to improve spatial resolution, then the spatial resolution improves, but the device complexity increases due to interference with laser delivery and ion flight
Solution Approach 1:
The patent separates the observation optical system from the laser delivery system, allowing the observation system to be positioned close to the sample for high spatial resolution without interfering with the laser beam path or ion flight trajectories. The separate optical axes enable independent optimization of each system's working distance.
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 design achieves high spatial resolution and maintains ion-generating and transport efficiency, enabling analysis of micro-sized samples with improved sensitivity and precision, suitable for analyzing specific portions of living cells.
Implementation Method 1
a laser-delivering system, including a laser-condensing optical system, for condensing and delivering an ionizing laser light onto a predetermined point
Implementation Method 2
laser-condensing optical system, for condensing and delivering an ionizing laser light
Implementation Method 3
Laser desorption ionization (LDI) is a technique in which laser light is delivered onto a sample to help the transfer of electrons within the substance that has absorbed the laser light
Implementation Method 4
a substance that is highly absorptive of laser light and easy to ionize is mixed beforehand into the sample, and this mixture is irradiated with laser light to ionize the sample
Implementation Method 5
Examples of the ion transport optical system 16 include an electrostatically-operated electromagnetic lens
Implementation Method 6
an electrostatically-operated electromagnetic lens
Implementation Method 7
The mass analyzer 17 separates the ions according to their mass-to-charge ratios
Implementation Method 8
The detector 18 produces an electric current indicative of the number of the received ions and outputs the electric current as a detection signal
Data Source
AI summary
In a mass spectrometer for carrying out mass analysis while microscopically observing a two-dimensional area of a sample 15, the observation position for selecting a target portion while observing an image of the sample 15 captured with a CCD camera 23 is separated from the analysis position for carrying out the mass analysis of the sample 15 by delivering laser light from the laser-delivering unit 20 onto the sample 15. The sample 15 is placed on a stage 13, which can be precisely moved between the observation position and the analysis position by a stage-driving mechanism 30. An observation optical system 24 can be set close to the sample 15 at the observation position, without impeding the flight of the ions generated from the sample 15 during the analysis or interfering with a laser-condensing optical system 22. Thus, the spatial resolution for observation is improved without deteriorating the ion-detecting efficiency.