JPS6316704B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a background correction mechanism for an emission spectrometer, and is a novel improvement particularly for correcting a transient signal background.

An example of this type of device that has been used in the past is shown in the first example.
As shown in the figure. In FIG. 1, reference numeral 1 denotes an excitation light source that heats and excites a sample and emits an emission spectrum. This emission spectrum is imaged by a lens 2 onto an entrance slit 3. 4 is a fan-shaped optical path bending member that rotates around an axis forming an angle α with the optical axis of the incident light; 5 is a motor that rotates the fan-shaped optical path bending member (FIG. 1 4); and 6
7 is a concave diffraction grating; 7 is an output slit; 8 is a photoelectric detector; 9 is an arithmetic circuit that subtracts the background intensity from the peak intensity of the spectral line; 10 is an integration circuit that integrates the output of the arithmetic circuit. , 11 is a display circuit.

The operating principle will be explained below. The light that has passed through the entrance slit in FIG. 1 and 2 passes through a fan-shaped optical path bending member whose rotation center is an axis that forms an angle α with the incident optical axis. As is well known, by inserting an optical path bending member within the optical axis, the wavelength extracted from the exit slit shown in FIG. 1 can be changed by Δ. Here, △ is △=t・α・n-1/n・D t: Thickness of the optical path bending member α: Angle between the optical axis and the optical path bending member n: Refractive index of the optical path bending member D: Reverse spectrometer It is expressed as line dispersion. Therefore, by rotating the fan-shaped optical path bending members and interposing them alternately, the exit slit 7
It is possible to alternately extract light with a wavelength λ and light with a wavelength λ+Δ. Now, if the wavelength λ is the peak wavelength of the spectral line and λ+△ is the background correction position, then the signal intensity Iλ+△ at the wavelength λ+△ is calculated from the signal intensity Iλ at the wavelength λ using the arithmetic circuit shown in FIG.
Background can be corrected.

However, in the conventional configuration as described above, since the angle α between the optical axis and the rotation axis of the sector-shaped optical path bending member cannot be changed, it has been impossible to change the background correction position.

The present invention aims to provide extremely effective means for quickly eliminating the above-mentioned drawbacks, and has a configuration in which the fan-shaped optical path bending member is provided with two rotation axes to improve the background correction mechanism.

Preferred embodiments of background correction according to the present invention will be described below with reference to the drawings. Second
In the figure, the one indicated by the reference numeral 21 heats and excites the sample with an excitation light source and emits an emission spectrum. 2
2 focuses this light onto an entrance slit 23 A lens 24 is a sector-shaped optical path that rotates around a first axis parallel to the longitudinal direction of the entrance slit and a second axis within a plane forming a Rowland circle. 25 is a fan-shaped optical path bending member disposed adjacent to the entrance slit 23, a detailed view of which is shown in FIG.
26 is a motor that rotates the fan-shaped optical path bending member around the first axis; 27 is a concave diffraction grating; 28 is an exit slit;
29 is a photodetector, 30 is an arithmetic circuit that executes Iλ-Iλ+Δ, 31 is an integration circuit that integrates the output of the arithmetic circuit 30, and 32 is a display circuit.

Next, the operation will be explained. The fan-shaped optical path bending member 24 shown in FIG. 3 is made of quartz or magnesium fluoride, and its thickness is optimally 0.5 to 3 mm.
Since the fan-shaped optical path bending members 24 are alternately searched into the optical axis every 1/4 rotation of the motor 25, the wavelength of the light extracted from the output slit 28 can be shifted by Δ. Further, a fan-shaped optical path bending member 14
Since it is rotatable around the first axis by the motor 26, the angle α between the second axis and the optical axis can be freely set. As explained earlier, △=t・α・
n-1/n. Because of the relationship D, Δ can be freely varied and any angle can be selected, so the background correction wavelength λ+Δ can be freely set.

As described above, according to the present invention, since the fan-shaped optical path bending member is configured to be rotatable in two axes, the background correction wavelength can be freely selected, and when another spectral line overlaps in the vicinity of the spectral line to be measured, the background correction wavelength can be freely selected. However, it is possible to perform accurate background correction by setting the background correction wavelength excluding the interference spectrum line.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a conventional example, FIG. 2 is a block diagram showing an embodiment of the present invention, and FIG. 3 is a perspective view showing details of a fan-shaped optical path bending member. 1 is an excitation light source, 2 is a lens, 3 is an entrance slit, 4 is a fan-shaped optical path bending member, 5 is a motor, 6
is a concave diffraction grating, 7 is an output slit, 8 is a photoelectric detector, 9 is an arithmetic circuit, 10 is an integration circuit, 11 is a display circuit, 21 is an excitation light source, 22 is a lens, 23 is an entrance slit, and 24 is a sector-shaped optical path. bending member, 25
is a motor, 26 is a motor, 27 is a concave diffraction grating, 28 is an exit slit, 29 is a photodetector, 3
0 is an arithmetic circuit, 31 is an integration circuit, and 32 is a display circuit.

Claims (1)

[Claims] 1. There is an optical axis consisting of an entrance slit, a diffraction grating, and an exit slit arranged in the spectrometer, and a lens or concave mirror that allows the light from the excitation light source to enter the entrance slit, and an optical axis adjacent to the entrance slit. and an optical path bending member is provided, and the optical path bending member is a disk centered on the rotation axis, and has a planar shape with a radial notch and the remaining fan-shaped portion, and the optical path bending member rotates with respect to the optical axis. . An optical emission spectrometer, characterized in that the cutout portion and the fan-shaped portion alternately cross over each other, and the angle formed by the rotation axis with respect to the optical axis can be arbitrarily set.