JP2000055733A - Multi-channel spectroscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a practical multi-channel spectroscope the astigmatism of which is suppressed low to provide a high resolution. SOLUTION: A diffraction grating 31 used as a dispersion element 3 for dispersing a light to be measured at specified angles according to the wavelength performs a light dispersing action in a main plane 30, on one side of which an incident slit 1 is provided and on the other side of which an array type detector 6 composed of detector elements arrayed in the main plane 30 is provided. A collimating optical element for collimating the light to be measured, incident from the incident slit and 1 and applying the collimated light incident on the diffraction grating 31, and image forming optical element for forming an image of the light to be measured, dispersed from the diffraction grating 31 at a different angle according to the wavelength on each detector element of the array type detector 6, are provided. The collimating optical element is a lower part 71 of a spherical mirror 7 and the image forming optical element is an upper part 72 of the spherical mirror 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-channel spectrometer capable of simultaneously measuring the intensity of light having different wavelengths.

[0002]

2. Description of the Related Art Spectrometry is actively performed in various industrial fields. For example, in the field of material analysis, spectrometry is actively used to analyze optical properties such as absorbance and light transmittance. In developing new light sources, it is essential to measure the emission spectrum of the light source. ing. In order to perform such a spectroscopic measurement, a spectrometer capable of measuring the intensity of light for each wavelength is required. In a spectrometer, light is dispersed for each wavelength in a dispersion element such as a diffraction grating, and only light of a specific wavelength is incident on a detector to measure the intensity. The spectrometer uses an optical system (hereinafter, referred to as a mount) including a dispersion element such as a diffraction grating that disperses light at different angles for each wavelength.

FIG. 5 is a diagram showing a schematic configuration of a mount of a typical conventional spectrometer. The mount for the spectrometer is a Littrow, Czerny-Turner
ner) shapes and the like are known. FIG. 5 shows a Czerny-Turner configuration, which is the most typical type. The Czerny-Turner type is configured so that light incident from an entrance slit 1 is reflected by a first spherical mirror 2 to be parallel light, and then incident on a diffraction grating used as a dispersion element 3. Then, the light dispersed by the diffraction grating is reflected by the second spherical mirror 4 and exits from the exit slit 5.
Has been reached. The second spherical mirror 4 is configured to form an image of the entrance slit 1 on the exit slit 5, and only light having a predetermined wavelength determined by the arrangement angle of the diffraction grating passes through the exit slit 5. .
The light that has passed through the exit slit 5 enters a detector (not shown), and the intensity thereof is detected. The arrangement angle of the diffraction grating is changed by a feed mechanism (not shown), and the intensity of each wavelength can be sequentially measured by wavelength feed.

[0004] The Czerny-Turner mount is often used in conventional spectrometers for the following reasons. Spectrometers, like other optical devices, also suffer from aberrations. The aberrations in the spectrometer include spherical aberration, astigmatism, coma, and the like. Spherical aberration is a rotationally symmetric aberration with respect to the optical axis, and is inevitable in a mount using a spherical mirror.

The astigmatism is defined as a plane (meridional surface) formed by the principal ray (a ray passing through the center of the spherical mirror) and the optical axis of the spherical mirror.
The aberration is caused by the fact that a meridional ray traveling upward and a sagittal ray traveling on a plane (sagittal plane) perpendicularly intersecting with the meridional plane on the principal ray are not formed at the same focal point. As shown in FIG. 5, in the Czerny-Turner type, the entrance slit 1, the first spherical mirror 2, the dispersive element 3,
The second spherical mirror 4 and the exit slit 5 are arranged on the same plane. To be more precise, the surface formed by the light beam (shown by a solid line in FIG. 5) that reaches the output slit 5 via the entrance slit 1, the first spherical mirror 2, the dispersive element 3, and the second spherical mirror 4 corresponds to a meridional surface. This plane coincides with a plane in the direction in which the light dispersion action of the dispersion element 3 works (hereinafter, a main plane). The entrance slit 1 and the exit slit 5 are long in a direction perpendicular to this plane. For this reason, the influence of astigmatism on the resolution of the spectrometer is reduced.

More specifically, in FIG.
The second spherical mirror 4 acts to project the image of the entrance slit 1 onto the exit slit 5, where the image is affected by astigmatism. In this case, since the dispersion direction of the dispersion element 3 is the direction of the meridional plane, it is necessary to form an image in the exit slit 5 at least in the direction of the meridional plane. If an image is not correctly formed in the direction of the meridional surface, light in different dispersion directions will be incident on the exit slit 5 so as to overlap, and the resolution will be reduced. Therefore, in the Czerny-Turner type, the exit slit 5 is configured so that the focal point of the meridional light beam is located. By sufficiently reducing the width of the entrance slit 1, a sufficiently high resolution can be obtained. Since the sagittal ray does not form an image at the exit slit 5, the image at the exit slit 5 is slightly longer than the entrance slit 1. In this case, light loss can be prevented by making the length of the exit slit 5 slightly longer than that of the entrance slit 1.

[0007] Coma is aberration caused by the fact that parallel rays entering the spherical mirror do not enter the spherical mirror at the same angle. In a spectrometer using a slit, unless there are special circumstances such as a high resolution type with a narrow slit width,
Coma does not pose a particular problem. However, in the case of a Littrow type mount in which the arrangement of the first and second spherical mirrors is not symmetrical with respect to the dispersive element, the coma aberration may affect the resolution. In this respect, in the case of the Czerny-Turner type mount, there is an advantage that the influence of coma is small because the arrangement of the spherical mirror is symmetric.

[0008]

As described above, conventional spectrometers often use a Czerny-Turner type mount which is excellent in that it is less affected by astigmatism and coma. However, according to the research of the inventor, it has been found that a Czerny-Turner type mount is not suitable for a multi-channel type spectrometer for which development of a highly practical one has recently been strongly demanded. This will be described below.

The above-described spectrometer is a single-channel spectrometer (monochromatic meter), and only one time can measure the intensity of light having a specific limited wavelength. It is not possible to measure the intensity of light at different wavelengths or wavelength ranges simultaneously. For example, when it is desired to check the ever-changing spectral characteristics of an object or to check the emission spectrum of a discontinuous light source such as a flash lamp, it is preferable to perform multi-wavelength intensity measurement simultaneously. Can not.

On the other hand, with the development of an array-type photodetector in which detection elements such as a diode array are arranged, a spectrometer capable of simultaneously measuring the intensity of different wavelengths in one measurement (referred to as a multi-channel spectrometer in this specification). Development has become possible. In the multi-channel spectrometer, the output slit 5 is not disposed, and the array type detector is disposed at the position of the output slit 5 (or a position optically equivalent thereto). The arrangement direction of the detection elements of the array type light receiver is made to coincide with the direction in which the diffraction grating 31 disperses light. Therefore, when a multi-channel spectrometer is constructed using the Czerny-Turner type mount shown in FIG. 5, it becomes as shown in FIG. FIG. 6 is a diagram showing a schematic configuration of a multi-channel spectrometer using a Czerny-Turner type mount. Light that is dispersed in different directions for each wavelength is incident on each detection element of the array type detector 6 shown in FIG. 6, and is subjected to photoelectric conversion independently for each detection element, so that the intensity of each separated wavelength is separated. At the same time.

However, when a Czerny-Turner type mount is used in a multi-channel spectrometer, there are the following problems. That is, as can be seen from FIG. 6, the light from the dispersion element 3 is dispersed at different angles depending on the wavelength and is incident on the second spherical mirror 4 at different angles. In the case of a monochromator, only light of a specific wavelength forms an image on the exit slit 5, so there was no problem. However, in the case of a multichannel spectrometer, light incident on the second spherical mirror 4 at a different angle for each wavelength. Is incident on each detection element of the array type detector 6, so that the amount of generation of coma differs for each wavelength. When a Czerny-Turner type mount is used, the angle of incidence on the second spherical mirror 4 varies greatly depending on the wavelength, and there is a problem that the influence of coma becomes extremely large particularly at a wavelength of a large angle of incidence. is there.

More specifically, in FIG.
The light of each wavelength dispersed from the dispersion element 3 is λ1,.
... ΛN, the angle θ at which λ1 enters the second spherical mirror 4
1, the angle θM when λM is incident on the second spherical mirror 4 is larger, and the angle θN when λN is incident on the second spherical mirror 4 is larger than the angle θM. As a result, light incident on the detection element at a position further away from the diffraction grating 31 will be incident on the second spherical mirror 4 at a larger incident angle, and the influence of coma will be stronger. For this reason, as a result of the dispersed light being overlapped and incident on adjacent wavelengths, the resolution is greatly reduced.

As described above, if a Czerny-Turner type, which has been generally used for a monochromator, is used for a mount of a multi-channel spectrometer, there is a problem that sufficient resolution cannot be obtained. In particular, in order to perform spectrometry in a wider wavelength range, the number of arrays of the detection elements increases, and the array-type detector 6 tends to be longer.
The problem of the increase in the aberration amount is further promoted. The invention of the present application has been made to solve such a problem, and an object of the invention is to provide a practical multi-channel spectrometer having high resolution with small aberrations.

[0014]

In order to solve the above-mentioned problems, the invention according to claim 1 of the present application is a multi-channel spectrometer capable of simultaneously measuring the intensities of lights of different wavelengths. An incident slit into which is incident, a dispersive element that disperses the measured light at a predetermined angle according to its wavelength, and a parallel optical element that converts the measured light incident from the incident slit into parallel light and enters the dispersive element, A detector into which light to be measured dispersed from the dispersive element is incident at different angles depending on the wavelength, and an imaging optical element for coupling the light to be measured to a light receiving surface of the detector; The detector is disposed on one side of the main plane that is a surface in the direction in which the light dispersion action of the element works, and the detector is an array-type detector in which detection elements are arranged in the direction of the main plane. On the other side across It has a configuration that has been. In order to solve the above problems, the invention described in claim 2 of the present application
In the configuration of claim 1, an incident-side reflecting mirror is provided on an optical path between the incident slit and the dispersion element, and an optical axis from the incident slit is bent by 90 degrees by the incident-side reflecting mirror. To reach the dispersion element. In order to solve the above-mentioned problem, claim 3 of the present application
According to the invention described in the first aspect, an emission-side reflecting mirror is provided on an optical path between the imaging element and the detector, and an optical axis from the imaging element is positioned on the emission side. It has a configuration in which it is bent 90 degrees by a reflecting mirror and reaches the detector. In order to solve the above problem, according to a fourth aspect of the present invention, in the configuration of the third aspect, the emission side reflection mirror and the detector connect the imaging element and the emission side reflection mirror. It has a configuration in which it is provided so as to be integrally movable along the direction of the optical axis.

[0015]

Embodiments of the present invention will be described below. FIG. 1 is a perspective view showing a schematic configuration of a multi-channel spectrometer according to an embodiment of the present invention. The multi-channel spectrometer shown in FIG. 1 includes an entrance slit 1 on which the light to be measured enters, a dispersion element 3 for dispersing light at a predetermined angle according to the wavelength of the light to be measured, and a measurement target incident from the entrance slit 1. A collimating optical element for converting light into collimated light and entering the dispersing element 3;
An array-type detector 6 on which light to be measured dispersed from
An imaging optical element for coupling light to be measured to the light receiving surface of the array type detector 6 is provided. In the present embodiment, as can be seen from FIG. 1, one spherical mirror 7 is also used for the parallel optical element and the imaging optical element.

As the dispersion element 3, a reflection type diffraction grating 3
1 is used. As can be seen from FIG. 1, the diffraction grating 31 is arranged such that the length direction of the groove is oriented in the vertical direction. The center of the surface of the diffraction grating 31 for dispersing light (hereinafter, diffraction surface) is located on the center axis 70 of the spherical mirror 7 (the axis connecting the center of the reflection surface of the spherical mirror 7 and the center of curvature) 70. In the present embodiment, as shown in FIG. 1, the light to be measured enters the diffraction grating 31 from obliquely below and is dispersed while being emitted obliquely upward. However, even in this case, the diffraction grating 31
The principal plane is horizontal as shown at 30 in FIG.

The entrance slit 1 is arranged below the main plane 30, as shown in FIG. Above the entrance slit 1, an entrance-side reflection mirror 81 is arranged. The incident-side reflecting mirror 81 is arranged at an angle of 45 degrees with respect to the horizontal plane. The light to be measured is vertically incident on the entrance slit 1 from below, is reflected on the incident side reflection mirror 81 and travels toward the spherical mirror 7. Note that, of the light traveling toward the spherical mirror 7, the light on the optical axis travels horizontally. As can be seen from FIG. 1, the length direction of the entrance slit 1 is optically perpendicular to the main plane 30.

The light reflected by the incident-side reflecting mirror 81 is configured to be reflected by a lower portion (hereinafter, a collimator portion) 71 of the spherical mirror 7 functioning as an optical element for collimating, and become parallel light. That is, the length of the optical axis from the entrance slit 1 to the collimator 71 is 1/1 / the radius of curvature of the collimator 71.
It is configured to be equal to two. As shown in FIG. 1, the diffraction grating 31 is located slightly above the collimator 71. Therefore, the light to be measured converted into parallel light by the collimator 71 travels slightly obliquely upward and reaches the diffraction grating 31.

The upper part 72 of the spherical mirror 7 functions as an imaging optical element for connecting the light to be measured dispersedly emitted from the diffraction grating 31 to the array type detector 6. That is, the length of the optical axis reaching the light receiving surface of the array type detector 6 from the spherical mirror 7 is equal to の of the radius of curvature of the spherical mirror 7. Similarly, the dispersed light incident on the upper part (hereinafter referred to as a condenser) 72 of the spherical mirror 7 functioning as an imaging optical element is a parallel light. Are connected to the light receiving surface. That is, on the light receiving surface of the array type detector 6, an image of the entrance slit 1 is formed for each wavelength.

As shown in FIG. 1, on the optical axis between the condenser section 72 and the array-type detector 6, an emission-side reflecting mirror 82 is provided.
Is arranged. The emission-side reflection mirror 82 is disposed at an angle of 45 degrees with respect to the horizontal direction. The optical axis from the condenser section 72 to the emission-side reflection mirror 82 is horizontal, and the optical axis is bent vertically by the emission-side reflection mirror 82 to reach the upper array type detector 6. As can be seen from the above description and FIG. 1, the arrangement of the spherical mirror 7, the diffraction grating 31, the incident-side reflecting mirror 81, and the emitting-side reflecting mirror 82 is symmetrical with respect to the main plane 30.

The array type detector 6 is an elongated box-shaped member as shown in FIG. The array type detector 6 will be described with reference to FIG.
Will be described. FIG. 2 is a schematic plan view illustrating a configuration of a detection element of the array type detector 6 in the multi-channel spectrometer of FIG. As shown in FIG. 2, the array type detector 6 includes a large number of detection elements 61.
Are arranged side by side. Each detection element 61 has a rectangular incident surface that is long in the width direction of the array-type detector 6 and is arranged in the length direction of the array-type detector 6. Detection element 6
Specifically, for example, an InGaAs photodiode can be used.

As can be seen from FIGS. 1 and 2, the light of each wavelength dispersed by the diffraction grating 31 is incident on a specific detection element 61 of the array type detector 6 according to the wavelength. More specifically, each detection element 61 of the array type detector 6 has a rectangular shape parallel to the entrance slit 1 and elongated in the same direction as the entrance slit 1. And
As described above, the condenser unit 72 forms an image of the incident slit 1 on each of the detection elements 61 with the light of each wavelength to be dispersed, and the light of each wavelength is photoelectrically converted and its intensity is measured.

More specifically, the array type detector 6 is provided with a signal reader (not shown) provided with an amplifier, an A / D conversion circuit, and the like. Further, the output signal of the signal reader is sent to a computer (not shown). The light of each wavelength incident on each detection element 61 is photoelectrically converted by the array type detector 6 and then amplified, converted into a digital signal and sent to a computer. Then, the computer processes the transmitted signal and displays the light intensity, that is, the spectrum of each wavelength, on a display. As is apparent from the above description, the spectrometer of the present embodiment is a multi-channel spectrometer, and a spectrum of a predetermined wavelength range can be obtained by one measurement without changing the arrangement angle of the diffraction grating 31.

Next, the mechanical structure of the multi-channel spectrometer of this embodiment will be described in more detail with reference to FIG. FIG. 3 is a front sectional view illustrating the mechanical structure of the multi-channel spectrometer shown in FIG. FIG.
As shown in (1), the multi-channel spectrometer of the present embodiment is housed in a rectangular parallelepiped case 91 as a whole. A diffraction grating holder 92 is provided inside one side wall of the case 91.
Are provided, and the diffraction grating 31 is held at a predetermined angle by the diffraction grating holder 92. The spherical mirror 7 is held by the spherical mirror holder 93 inside the other side wall, and faces the diffraction grating 31.

An opening is formed at a predetermined position of the bottom plate of the case 91, and the entrance slit 1 is provided so as to fit into the opening. A guide tube 94 is fixed to the case 91 so as to surround the optical axis to the entrance slit 1. The end of the optical fiber for guiding the light to be measured to the entrance slit 1 may be connected to the guide tube 94.

The incident-side reflecting mirror 81 is held by an incident-side reflecting mirror holder 95 fixed to a case 91.
A relatively large opening is provided in the upper plate portion of the case 91, and the array type detector 6 is located in this opening. A detector holding plate 96 is provided above the case 91 so as to close this opening. Detector holding plate 9
Reference numeral 6 denotes an array type detector 6 fixedly held on the lower surface thereof.

As shown in FIG. 3, the detector holding plate 9
The output-side reflecting mirror holder 97 is fixed to 6. The emission-side reflector holding member 97 extends downward from the detector holding plate 96, bends toward the spherical mirror 7, and holds the emission-side reflector 82 at its tip. The emission-side reflection mirror 82 holds the emission-side reflection mirror so that the horizontal optical axis from the condenser 72 is bent 90 degrees and goes vertically upward, and the optical axis coincides with the center of the light-receiving surface of the array-type detector 6. It is held by the tool 97.

A major feature of the structure shown in FIG. 3 is that the emission-side reflection mirror 82 and the array-type detector 6 can move integrally in the optical axis direction connecting the condenser section 72 and the emission-side reflection mirror 82. That is. More specifically, the detector holding plate 96 is attached to the case 91 via a linear moving mechanism (not shown) using a guide rail or the like. The linear movement mechanism is provided with a fine adjustment mechanism (not shown) such as a micrometer, so that the arrangement positions of the array type detector 6 and the emission side reflection mirror 82 in the optical axis direction can be adjusted very finely. ing.

Fine adjustment of the arrangement position of the array type detector 6 and the emission side reflection mirror 82 is very convenient for adjustment of the entire optical system when the spectrometer is assembled. That is, when the arrangement position of the array type detector 6 and the emission side reflecting mirror 82 is moved along the optical axis, the optical path length from the capacitor unit 72 to the array type detector 6 changes. Therefore, by finely adjusting the arrangement positions of the array-type detector 6 and the emission-side reflecting mirror 82 so that the light-receiving surface of the array-type detector 6 accurately matches the position of the focal point of the condenser unit 72, the array-type detector 6 The light is accurately focused on the light receiving surface of the light source, and the resolution and brightness of the measurement can be sufficiently obtained.

The multi-channel spectrometer of the present embodiment has the following advantages as compared with a conventional one using a Czerny-Turner type mount. This will be described with reference to FIG. FIG. 4 is a plan view of the multi-channel spectrometer shown in FIG. 1, and is a diagram showing an image formation state of light dispersed from the diffraction grating 31. Although FIG. 4 shows a state in which the light is not reflected by the exit-side reflecting mirror 82 for the sake of illustration, it is optically equivalent to that shown in FIG.

As described above, one of the problems of the optical system that forms an image using the spherical mirror 7 like the Czerny-Turner type or the mount of the present embodiment is coma aberration. As described above, in the multi-channel spectrometer using the Czerny-Turner type mount, the angle of incidence at the time of incidence on the second spherical mirror 74 is increased by the angle dispersed from the diffraction element, and the influence of coma is increased. Would.

On the other hand, when examining the spectrometer of the present embodiment, of the light incident on the condenser 72, FIG.
As shown in (2), the light incident along the central axis 70 of the spherical mirror 7 in plan view has an incident angle of 0 degree in plan view. Then, the light that travels farthest from the central axis 70 and enters the capacitor unit 72 has the largest incident angle, but the light incident state on the capacitor unit 72 is still symmetrical with respect to the central axis 70, Compared with the case shown in FIG. 6, the change amount of the incident angle is almost halved. At this time, the influence of coma is reduced to less than half.

Also, as can be seen from FIG.
Light travels obliquely upward at an angle to the main plane 30. Therefore, the angle of incidence on the condenser section 72 as viewed from the front slightly differs depending on the dispersion angle from the diffraction grating 31. However, the output side reflecting mirror 82 is
By arranging at a position close to the above, it is possible to further reduce the angle of the obliquely upward movement. For this reason, the difference in the incident angle when viewed from the front is almost negligible, and no coma aberration that affects the resolution is generated.

In the mount shown in FIG. 1, light travels obliquely upward with respect to a central axis 70 passing through the center of the spherical mirror 7 and enters the condenser section 72. The plane is perpendicular to 30. The sagittal surface is a surface perpendicular to the original surface in the light beam incident on the condenser section 72. Therefore, the method of forming astigmatism differs from the mount shown in FIG. 5 by 90 degrees.

In the above description, the reflection type diffraction grating 31 is taken as an example of the dispersion element 3, but the transmission type diffraction grating 31 is used.
Alternatively, a configuration such as a combination of a prism and a reflecting mirror can be adopted. The effect of reducing the amount of coma described above can be similarly obtained without using the incident side reflecting mirror 81 and the emitting side reflecting mirror 82. However, if the incident-side reflecting mirror 81 and the emitting-side reflecting mirror 82 are not used, the entrance slit 1 and the array-type detector 6 will be disposed immediately below or above the diffraction grating 31, and the entrance slit 1 and the array-type detection The arrangement may be difficult depending on the size of the container 6. It is effective to increase the radius of curvature of the spherical mirror 7 to reduce the influence of coma aberration and the like. However, if the radius of curvature is increased, the optical path length from the entrance slit 1 to the collimator 71 and the There is a drawback that the optical path length to the array type detector 6 becomes long, and the entire spectrometer becomes long horizontally. However, when the incident-side reflecting mirror 81 and the emitting-side reflecting mirror 82 are used, the optical axis is bent vertically.
It can be compact without being lengthened sideways.

[0036]

As described above, according to the first aspect of the present invention, in a multi-channel spectrometer using an array type detector, the influence of coma is reduced by half, and the resolution and brightness are reduced. Excellent measurements can be made. Also,
According to the second aspect of the invention, in addition to the effect of the first aspect,
The arrangement of the entrance slit becomes easy, and the entire spectrometer can be made compact. According to the third aspect of the present invention, in addition to the effect of the first aspect, the arrangement of the array-type detector is facilitated, and the entire spectrometer can be made compact. Further, according to the invention of claim 4, in addition to the effect of the above-described claim 3, the adjustment of the optical system can be easily performed, and the configuration becomes more practical.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a schematic configuration of a multi-channel spectrometer according to an embodiment of the present invention.

FIG. 2 is a schematic plan view illustrating a configuration of a detection element of an array type detector 6 in the multi-channel spectrometer of FIG.

FIG. 3 is a front sectional view illustrating a mechanical structure of the multi-channel spectrometer shown in FIG. 1;

FIG. 4 is a plan view of the multi-channel spectrometer shown in FIG. 1, showing an image formation state of light dispersed from a diffraction grating 31;

FIG. 5 is a diagram showing a schematic configuration of a mount of a conventional typical spectrometer.

FIG. 6 is a diagram showing a schematic configuration of a multi-channel spectrometer using a Czerny-Turner type mount.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 entrance slit 3 dispersive element 31 diffraction grating 30 principal plane 31 diffraction grating 6 array detector 7 spherical mirror 71 collimator unit 72 condenser unit 81 incident-side reflecting mirror 82 emission-side reflecting mirror

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[Procedure amendment]

[Submission date] April 12, 1999 (1999.4.1
2)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 3

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] Claim 4

[Correction method] Change

[Correction contents]

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction contents]

On the other hand, with the development of an array-type detector in which detection elements such as diode arrays are arranged, a spectrometer (herein called a multi-channel spectrometer) capable of simultaneously measuring the intensity of different wavelengths in one measurement is called. Development has become possible. In the multi-channel spectrometer, the output slit 5 is not disposed, and the array type detector is disposed at the position of the output slit 5 (or a position optically equivalent thereto). The arrangement direction of the detection elements of the array type detector is made to coincide with the direction in which the dispersion element 3 disperses light. Therefore, when a multi-channel spectrometer is constructed using the Czerny-Turner type mount shown in FIG. 5, it becomes as shown in FIG. FIG. 6 is a diagram showing a schematic configuration of a multi-channel spectrometer using a Czerny-Turner type mount. Light that is dispersed in different directions for each wavelength is incident on each detection element of the array type detector 6 shown in FIG. 6, and is subjected to photoelectric conversion independently for each detection element, so that the intensity of each separated wavelength is separated. At the same time.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction contents]

More specifically, in FIG.
The light of each wavelength dispersed from the dispersion element 3 is λ1,.
... ΛN, the angle θ at which λ1 enters the second spherical mirror 4
1, the angle θM when λM is incident on the second spherical mirror 4 is larger, and the angle θN when λN is incident on the second spherical mirror 4 is larger than the angle θM. After all, minutes
The light incident on the detection element at a position further away from the diffuser element 3 is incident on the second spherical mirror 4 at a larger incident angle, and the influence of coma becomes stronger. For this reason, as a result of the dispersed light being overlapped and incident on adjacent wavelengths,
The resolution is greatly reduced.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction contents]

[0014]

In order to solve the above-mentioned problems, the invention according to claim 1 of the present application is a multi-channel spectrometer capable of simultaneously measuring the intensities of lights of different wavelengths. An incident slit into which is incident, a dispersive element that disperses the measured light at a predetermined angle according to its wavelength, and a parallel optical element that converts the measured light incident from the incident slit into parallel light and enters the dispersive element, A detector into which light to be measured dispersed from the dispersive element is incident at different angles depending on the wavelength, and an imaging optical element for coupling the light to be measured to a light receiving surface of the detector; The detector is disposed on one side of the main plane that is a surface in the direction in which the light dispersion action of the element works, and the detector is an array-type detector in which detection elements are arranged in the direction of the main plane. On the other side across It has a configuration that has been. In order to solve the above problems, the invention described in claim 2 of the present application
In the configuration of claim 1, an incident-side reflecting mirror is provided on an optical path between the incident slit and the dispersion element, and an optical axis from the incident slit is bent by 90 degrees by the incident-side reflecting mirror. To reach the dispersion element. In order to solve the above-mentioned problem, claim 3 of the present application
The invention according to claim 1, wherein in the configuration according to claim 1, the imaging is performed.
An emission-side reflecting mirror is provided on an optical path between the optical element for imaging and the detector, and an optical axis from the imaging optical element is bent by 90 degrees by the reflecting mirror on the emission side, and is reflected by the detector. Has a configuration that has reached. To solve the above problems,
According to a fourth aspect of the present invention, in the configuration of the third aspect, the exit-side reflecting mirror and the detector are connected to each other for the imaging .
It has a configuration in which it is provided so as to be integrally movable along the direction of the optical axis connecting the optical element and the exit-side reflecting mirror.

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0031

[Correction method] Change

[Correction contents]

As described above, one of the problems of the optical system that forms an image using the spherical mirror 7 like the Czerny-Turner type or the mount of the present embodiment is coma aberration. As described above, Czerny - In multichannel spectrometer using Turner-shaped mount, different increases depending on the angle of incidence angle at the time of entering the second spherical mirror 4 are dispersed from the diffraction element, the influence of the coma aberration becomes stronger Would.

[Procedure amendment 7]

[Document name to be amended] Statement

[Correction target item name] Explanation of sign

[Correction method] Change

[Correction contents]

[Description of Signs] 1 Incident slit 3 Dispersion element 30 Main plane 31 Diffraction grating 6 Array type detector 7 Spherical mirror 71 Collimator unit 72 Capacitor unit 81 Incident-side reflecting mirror 82 Exit-side reflecting mirror

Claims (4)

[Claims] 1. A multi-channel spectrometer capable of simultaneously measuring the intensities of lights of different wavelengths, wherein an incident slit into which the light to be measured is incident, and the light to be measured are dispersed at a predetermined angle according to the wavelength. A dispersive element, a collimating optical element that converts the light to be measured incident from the entrance slit into parallel light and impinges on the dispersive element, and a detector to which the light to be measured dispersed from the dispersive element is incident at different angles according to the wavelength. ,
An imaging optical element for forming light to be measured on a light receiving surface of the detector, wherein the entrance slit is disposed on one side of a main plane that is a surface in a direction in which the light dispersion action of the dispersion element works. Wherein the detector is an array-type detector in which detection elements are arranged in a direction of a main plane, and is arranged on the other side of the main plane. 2. An incident-side reflecting mirror is provided on an optical path between the incident slit and the dispersing element, and an optical axis from the incident slit is bent by 90 degrees by the incident-side reflecting mirror to form the dispersion mirror. 2. The multi-channel spectrometer according to claim 1, wherein the multi-channel spectrometer reaches the element. 3. An emission-side reflecting mirror is provided on an optical path between the imaging element and the detector, and an optical axis from the imaging element is bent by 90 degrees by the emission-side reflecting mirror. The multi-channel spectrometer according to claim 1, wherein the detector reaches the detector. 4. The light-emitting device according to claim 1, wherein the emission-side reflection mirror and the detector are provided so as to be integrally movable along a direction of an optical axis connecting the imaging element and the emission-side reflection mirror. 4. The multi-channel spectrometer according to claim 3, wherein: