JP3788046B2 - Optical emission spectrometer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an emission spectroscopic analyzer that performs quantitative and qualitative measurement of elements, and more particularly to a spectroscope that performs multi-element simultaneous analysis.
[0002]
[Prior art]
A spectroscope used in an emission spectroscopic analysis apparatus causes light incident from an entrance slit to undergo wavelength dispersion by a dispersion element such as a diffraction grating, and then forms an image on the exit slit. This spectrometer is provided with a single exit slit and a monochromator that sequentially changes the analysis wavelength to the exit slit by rotating the dispersive element, and a plurality of exit slits instead of rotating the dispersive element. There is a polychromator that can be installed and analyze multiple wavelengths simultaneously.
[0003]
An example of an emission spectroscopic analyzer is shown in FIG. 5, and the spectrometer is of a polychromator type. In FIG. 5, light emitted by discharge between the sample and the counter electrode is incident on the entrance slit 10, and wavelength dispersion is performed by the diffraction grating 11, and exit slits 12a to 12d are disposed at wavelength positions corresponding to the respective elements. The light intensity of each wavelength that has passed through the exit slits 12a to 12d is converted into an electrical signal by the photomultipliers 13a to 13d, and qualitative and quantitative values of each element are output by computer processing.
[0004]
Since all the optical elements (including the slits) are fixed in this polychromator, their positions must be adjusted so that they are strictly disposed at predetermined positions. In particular, when the exit slits are close to each other in the measurement wavelength, it is necessary to arrange the exit slits close to each other, so it is necessary to employ a complicated exit slit adjustment mechanism such as a fine screw in a narrow space. Can not.
[0005]
Therefore, conventionally, an exit slit adjusting mechanism as shown in FIGS. FIG. 3 is an exploded view of the assembly of the parts constituting the adjusting mechanism, and FIG. 4 is a front view when they are assembled. As shown in FIG. 3, an eccentric shaft 3 forming a cam mechanism is prepared, and the eccentric shaft 3 is inserted into the slot holes provided in the upper and lower ends of the outlet slit movable base 2 so that the eccentric portion of the shaft is inserted. The eccentric shaft 3 is attached to the base 4. As a result, when the eccentric shaft 3 is finely rotated around the rotation center 5, the exit slit movable base 2 moves in the wavelength dispersion direction by the cam mechanism of the eccentric shaft, and the position of the exit slit 1 can be adjusted. In this case, the portion in contact with the eccentric shaft is grooved with a tight fitting dimension with respect to the shaft diameter, and a slot hole with a tight parallel surface tolerance is required.
[0006]
[Problems to be solved by the invention]
The exit slit of the conventional spectroscope for emission spectroscopic analysis is configured as described above. However, the spectroscope used for emission spectroscopic analysis generally requires high resolution, and the inverse dispersion is about 0.5 nm / mm. In order to match the peak of the wavelength profile to the exit slit, it is necessary to adjust the position in the dispersion direction on the order of microns. However, in the conventional structure, when the tolerance between the grooves is small, a gap is generated between the eccentric shaft forming the cam mechanism (see FIG. 4), and a desired amount of movement cannot be obtained with respect to the rotation of the eccentric shaft. As a result, smooth movement is impossible and precise adjustment becomes impossible. Also, with negative tolerances, it cannot be inserted into the eccentric shaft, and even if it is forcibly inserted, the movement is hard and smooth adjustment is not possible. In this case, the movement becomes softer as it is used, but there is a problem that a gap is generated between the shaft and the shaft.
[0007]
The present invention has been made in view of such circumstances, and provides an emission spectroscopic analyzer having an exit slit adjusting mechanism that does not create a gap between the eccentric shaft forming the cam mechanism and the exit slit movable base. The purpose is to do.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the emission spectroscopic analysis apparatus of the present invention has a two-plate leaf spring structure using an elastic material for the movable part of the exit slit of the spectrometer, and the eccentric shaft forming the cam mechanism is the above-described eccentric shaft. The eccentric shaft diameter sandwiched between the two leaf spring portions is set to be plus tolerance with respect to the interval between the two leaf spring portions so as to be sandwiched between the two leaf spring portions.
Thus, the two leaf spring portions of the exit slit movable base cooperate with the eccentric shaft forming the cam mechanism, and a gap between the eccentric shaft and the outlet slit movable base is not generated.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
One embodiment of the outlet slit adjusting mechanism of the spectroscope for emission spectral analysis of the present invention will be described with reference to FIGS. FIG. 1 is an assembly drawing of the exit slit portion, and the assembling method is the same as that in FIG. FIG. 2 is a front view of the exit slit portion. Reference numeral 1 denotes an exit slit. A slit hole having a width of 20 to 50 μm is formed in a very thin plate by laser processing, and an entrance slit image of monochromatic light dispersed in wavelength is formed here, and only the wavelength of the target element is detected by photoelectric conversion. To the photomultiplier. Reference numeral 2 denotes an exit slit movable base, in which a stainless spring steel having a thickness of 0.3 mm is bent into a U shape, and an exit slit 1 is bonded to the bottom thereof. Furthermore, two pieces of leaf spring portions 2S are formed at the upper and lower ends of the exit slit movable base 2 so as to extend. Reference numeral 3 denotes an eccentric shaft that forms a cam mechanism. A cam mechanism in which the shaft diameter and the rotation center 5 of the portion fitted to the base 4 are different from the shaft diameter and the shaft center of the portion sandwiched by the outlet slit movable table 2. The axis center and the rotation center 5 are shifted by an amount necessary as a wavelength dispersion direction adjusting movement width of the exit slit 1. And the exit slit 1 is fixed by fitting the eccentric shaft 3 to the base 4 as a result.
[0010]
The outlet slit portion is assembled by sandwiching the eccentric portion of the eccentric shaft 3 by the two leaf spring portions 2S of the outlet slit movable base 2 and fitting the eccentric shaft 3 to the base 4. As a result, the gap between the eccentric shaft 3 and the exit slit movable base 2 is eliminated.
[0011]
Next, an adjustment method for finely adjusting the exit slit movable base 2 in the wavelength dispersion direction and matching the peak of the wavelength profile with the exit slit 1 will be described. When the eccentric shaft 3 is rotated, the shaft that is fitted to the base 4 and the shaft that is sandwiched between the two leaf spring portions 2S of the movable outlet slit 2 are made eccentric. The slit movable base 2 can be moved in the wavelength dispersion direction by e (sin θ), where θ is the rotation angle of the eccentric shaft 3 and e is the amount of eccentricity. Since the exit slit 1 is bonded to the exit slit movable base 2, unlike the conventional method, the exit slit 1 can be smoothly and reliably adjusted by a target amount.
[0012]
Although the features of the present invention are as described above, the configuration of the leaf spring portion 2S may be formed as the same body as the exit slit movable base 2 as shown in the drawing, or a separate member may be provided in a protruding manner. May be. For example, the exit slit movable base 2 can be made of a metal material, and the leaf spring portion 2S can be made of a resin material.
[0013]
【The invention's effect】
The emission spectroscopic analysis apparatus of the present invention is configured as described above, and for adjusting the exit slit, the eccentric shaft forming the cam mechanism is sandwiched between the two leaf spring portions of the exit slit movable base. A gap does not occur between the eccentric shaft and the exit slit movable base, and the position adjustment of the exit slit can be performed stably and precisely. Further, in this structure, the tolerance of the portion sandwiching the eccentric shaft does not have to be so severe, and can be realized by a sheet metal structure, so that the mechanism can be manufactured stably and efficiently by using a mold.
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment of an exit slit portion of an emission spectroscopic analyzer of the present invention.
FIG. 2 is a diagram showing a main part of the present invention.
FIG. 3 is a view showing an exit slit portion of a conventional emission spectroscopic analyzer.
FIG. 4 is a view showing an exit slit portion of a conventional emission spectroscopic analyzer.
FIG. 5 is a diagram showing an emission spectroscopic analyzer.
[Explanation of symbols]
1 ... Exit slit 2 ... Exit slit movable base 2S ... Plate spring part 3 ... Eccentric shaft 4 ... Base 5 ... Eccentric shaft rotation center

Claims (1)

In the emission spectroscopic analyzer in which the position adjustment of the exit slit of the spectrometer performing the multi-element simultaneous analysis is performed by adjusting the movement of the exit slit in the wavelength dispersion direction by the cam mechanism of the eccentric shaft, the movable base having the exit slit is provided. An emission spectroscopic analysis apparatus characterized in that two pieces of leaf springs are provided and the eccentric shaft is sandwiched between the two pieces of leaf springs.

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