JP2755878B2 - Array type photodetector positioning method and spectrometer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spectrometer comprising a concave diffraction grating on which a light beam to be split is incident, and an array type light receiving element for receiving diffracted light diffracted from the concave diffraction grating. The present invention also relates to a method for positioning an array type light receiving element provided in the spectrometer.

[0002]

2. Description of the Related Art Conventionally, this type of spectrometer is shown in FIG.
The configuration shown in FIG. That is, it is configured to include a slit 3 into which a light beam to be split is incident, a plane mirror 5, a concave diffraction grating 4, and an array-type light receiving element 6 for receiving diffracted light diffracted from the concave diffraction grating. The spectrometer is configured so that the light split by the concave diffraction grating can receive the light beam split at the focal plane position, and an array type light receiving element is arranged at this focal plane position to perform detection. Do it. Therefore, in a spectrometer,
Although it is necessary to dispose the array type light receiving element in an appropriate positional relationship with respect to the concave diffraction grating, it is difficult to accurately measure the distance between the optical components. Conventionally, this focal plane alignment is usually performed by an optical method. That is, as shown in FIG. 5 (b), laser light enters the spectrometer from two directions through a slit, obtains diffracted light from a concave diffraction grating, and focuses on the light receiving element surface. , The position of each part was adjusted.

[0003]

However, in this method, the position of the array type light receiving element can be confirmed only at a point, and in order to confirm the entire area, it is necessary to prepare laser light sources having different wavelengths. The equipment became large-scale and it took a long time to adjust. Further, it is necessary to change the irradiation angle of the laser beam to detect whether or not the focal plane position is deviated. However, in this case as well, the device system becomes large and workability is poor. Therefore, it has been difficult to easily appropriately set the position of the array type light receiving element. An object of the present invention is to solve the above problems.

[0004]

In order to achieve the above object, a method of positioning an array type light receiving element according to the present invention is characterized in that an adjusting light beam having a spectral peak at least at two wavelengths is formed by a concave diffraction grating. A first step of obtaining the first detection information by detecting the diffracted light with the array type light receiving element and diffracted light of the first specific position, and diffusing the adjusting light beam with a concave diffractive surface different from the first specific position. Incident on the second specific position of the grating, the second step of detecting the diffracted light with an array type light receiving element to obtain second detection information, the position of at least a pair of elements that receive peaks of at least two wavelengths So that the first detection information and the second detection information match each other,
It is provided with a position adjusting step of adjusting the position of the array type light receiving element, and further, the characteristic configuration of the spectrometer is
Irradiation means for irradiating an adjustment light beam having a spectral peak at at least two wavelengths as a position adjustment light source of the array type light receiving element, and adjustment light rays from the irradiation means to two different portions of the concave diffraction grating There is provided an incident light position adjusting means for individually entering the bundles. And
The operation and effect are as follows.

[0005]

The characteristic of the focal plane inherent to the concave diffraction grating is that, when the light-receiving element is at the focal plane position, the diffracted light from each part of the diffraction grating is received by the element having the same element number as the specific spectrum light. You. Accordingly, in the present application, this characteristic is used in reverse to irradiate a specific adjusting light beam to two different portions of the concave diffraction grating, and the spectra of these diffracted lights are received by the same specific element. The positions of a series of array-type light receiving elements are set as regular positions. Here, whether or not the spectra match in the arrangement direction of the elements is confirmed by comparing at least two peak wavelength positions existing in the adjustment light beam. By the way, in the spectrometer, the irradiation light source capable of irradiating the above-mentioned specific adjusting light beam is provided, and the first and second steps described above are provided with the incident light position adjusting means, and the array type light receiving element is provided. Positioning can be performed.

[0006]

Therefore, it is not necessary to prepare a laser light source having two wavelengths, and since the element position can be confirmed in a state where it is arranged as a surface, the adjustment work can be easily performed and the apparatus system can be easily controlled. A very simple configuration is required. Here, since the shift of the focal plane of the spectrometer can be grasped over the entire wavelength range, it is immediately known in which direction the light receiving element should be moved. Therefore, the optical axis can be easily and quickly adjusted, and the automatic adjustment can be easily performed.

[0007]

An embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows the configuration of the spectrometer 1, and FIG. 2 shows a view (a-a direction view) of the shielding plate 2 with a window provided in the spectrometer 1 as viewed from the incident side. .

First, the schematic configuration of the spectrometer 1 will be described. The spectrometer 1 includes a slit 3 into which a light beam to be split is incident, a plane reflecting mirror 5 for guiding the light beam passing through the slit 3 to a concave diffraction grating 4, a concave diffraction grating 4, and a concave diffraction grating. And an array type light receiving element 6 for receiving the diffracted light diffracted from the diffraction grating 4. The windowed shielding plate 2 is provided on the front side of the concave diffraction grating 4.
As shown in FIGS. 1 and 2, the window-equipped shielding plate 2 has an opening 2 a having an area smaller than the light receiving surface of the diffraction grating 4, and the window-equipped shielding plate 2 extends along the concave diffraction grating 4. Slidably (direction b). Therefore, the shielding plate with window 2
Is moved, the portions of the light beam incident on the concave diffraction grating 4 and the diffracted light diffracted therefrom and received by the array-type element 6 are limited and selected. The window-equipped shielding plate 2 is referred to as incident light position adjusting means. On the other hand, the array type light receiving element 6
A device necessary for positioning includes a white light source 7 for irradiating a white light beam, and an adjustment filter 8 for transmitting the white light beam to obtain an adjustment light beam having a spectral peak at two wavelengths. Have been. Here, the white light source 7 is a general light source, and the white light beam is a broad light beam with low directivity.

The adjustment principle employed when positioning the array type light receiving element 6 will be described below. In FIG. 3, the solid line and the broken line show the peak position (wavelength λ ₁ λ ₂ ) image forming direction of the diffracted light of the adjusting light beam when the shielding plate with window 2 has a different positional relationship. . Furthermore, FIG.
(B) shows the spectrum distribution in these states (the diffraction image from the A portion of the concave diffraction grating 4 is shown by a solid line, and the diffraction image from the B portion is shown by a broken line). As can be seen from the relationship in the figure, when the array type light receiving element 6 coincides with the focal plane, the spectrum of the diffracted light diffracted from the different portions (A and B) of the concave diffraction grating 4 is received. They match on the element 6 (shown in FIG. 4B). On the other hand, as shown in FIG. 3, when the array-type light receiving element 6 is out of the focal plane, the two spectra are shifted (FIG. 4).
(Shown in (a)). Therefore, in order to confirm the coincidence with the focal plane, the position of the array-type light receiving element 6 may be adjusted so that the peak positions P1 and P2 of the array-type elements are detected by the same element.

The procedure for positioning the array type light receiving element 6 will be described below. 1) An adjustment filter 8 is provided in front of the white light source 7, and an adjustment light beam transmitted through the adjustment filter 8 is made to enter the spectrometer 1. 2) The shielding plate with window 2 is set at the first position, the light beam for adjustment is incident on the first specific position A of the concave diffraction grating, and the diffracted light is detected by the array-type light receiving element 6 for the first detection. get information. This step is called a first step. 3) The shielding plate with window 2 is set at a second position different from the first position, and the adjusting light beam is transmitted to the second specific position B of the concave diffraction grating.
And the diffracted light is detected by the array type light receiving element 6 to obtain second detection information. This step is called a second step. 4) The position of the array-type light receiving element is adjusted such that the positions of the pair of elements that receive the peaks of the two wavelengths match each other between the first detection information and the second detection information. This step is called a position adjustment step.

In the above embodiment, the positions of these spectra are compared by receiving the diffracted lights from the respective portions at different times, but a plurality of openings are provided in the shielding plate with windows. In the incident stage, an adjusting light beam having a plurality of peaks may be made incident, and when the same number of peaks are detected in the array type light receiving element, it may be determined that the element is located on the focal plane. .

In the claims, reference numerals are provided for convenience of comparison with the drawings, but the present invention is not limited to the configuration shown in the accompanying drawings.

[Brief description of the drawings]

FIG. 1 shows a configuration of a spectrometer.

FIG. 2 is an aa direction view showing a configuration of a window plate.

FIG. 3 is a diagram showing a relationship between diffracted light from different concave diffraction grating portions and a light receiving element.

FIG. 4 is a diagram showing a spectrum distribution when the light receiving element is out of the focal plane and when the light receiving element is in agreement with the focal plane;

FIG. 5 is a diagram showing a configuration of a conventional spectrometer and a positioning state of a light receiving element thereof.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Spectrometer 2 Incident light position adjusting means 4 Concave diffraction grating 6 Array type light receiving element 7 Irradiating means 8 Irradiating means A First specified position B Second specified position

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G01J 3/36 G01J 3/02

Claims (2)

(57) [Claims] 1. A concave diffraction grating (4) on which a light beam to be split is incident, and an array type light receiving element (6) for receiving diffracted light diffracted by the concave diffraction grating (4). A method for positioning an array-type light receiving element of a spectrometer (1), comprising: adjusting an adjusting light beam having a spectrum peak at least at two wavelengths to a first specific position (A) of the concave diffraction grating (4). A first step of receiving the diffracted light and detecting the diffracted light with the array-type light receiving element (6) to obtain first detection information; and adjusting the adjustment light beam different from the first specific position (A). Incident on the second specific position (B) of the concave diffraction grating,
A second step of detecting the diffracted light with the array-type light receiving element (6) to obtain second detection information, wherein the position of at least one pair of elements that receive the peaks of at least two wavelengths is the first detection. A method for positioning an array-type light-receiving element, comprising a position adjusting step of adjusting the position of the array-type light-receiving element (6) so that information and the second detection information match each other. 2. A device comprising: a concave diffraction grating (4) on which a light beam to be split is incident; and an array-type light receiving element (6) for receiving diffracted light diffracted from the concave diffraction grating (4). Irradiating means (7), (8) for irradiating an adjusting light beam having a spectrum peak at least at two wavelengths as a position adjusting light source of said array type light receiving element; A spectrometer provided with incident light position adjusting means (2) for individually entering the adjusting light beams from the irradiation means (7) and (8) into two different portions of the grating (4).