JP2021177158A - Spectroscope - Google Patents

Abstract

To make it possible to take out, from a spectroscope, a sufficient quantity of primary diffraction light within a wide wavelength range.SOLUTION: A spectroscope 100 of the present invention comprises: a diffraction grating 2 that is arranged in a housing 1 and disperses light incident from an entrance 11 and emits light with a target wavelength from an exit 12; a rotation drive mechanism 5 that rotates the diffraction grating; storage units 74, 75 that store an operation expression for calculating the rotation angle position of the diffraction grating corresponding to the target wavelength; and a control unit 7 that causes the rotation drive mechanism to rotate a wavelength dispersion element so that the diffraction grating is located at a predetermined rotation angle position. The diffraction grating and the rotation drive mechanism are configured in the housing such that in a state in which the diffraction grating is located at a rotation angle position corresponding to a first wavelength, an optical axis of light directed from the diffraction grating to the exit when light including light with the first wavelength is made incident from the entrance passes through a predetermined range at the center of the exit, and in a state in which the diffraction grating is located at a rotation angle position corresponding to a second wavelength, an optical axis of light directed from the diffraction grating to the exit when light including light with the second wavelength is made incident from the entrance passes through a predetermined range of the exit.SELECTED DRAWING: Figure 1

Description

The present invention relates to a spectroscope incorporated in a spectrophotometer such as an ultraviolet visible light spectrophotometer, an atomic absorption spectrophotometer, a tunable monochromatic light source, and the like.

Spectrophotometers such as an ultraviolet visible light spectrophotometer and an atomic absorption spectrophotometer are known as devices for performing qualitative and quantitative analysis of a sample. The spectrophotometer irradiates a sample with monochromatic light of a predetermined wavelength and measures the amount of transmitted light at that time to obtain the absorbance at the predetermined wavelength and performs qualitative and quantitative analysis of the sample. In a spectrophotometer, a spectroscope (monochromator) is usually used to obtain monochromatic light having a predetermined wavelength.

The spectroscope includes a housing having an inlet slit and an exit slit, a diffraction grating (wavelength dispersing element) housed in the housing, and a rotation driving mechanism for changing the angle of the diffraction grating with respect to the light incident from the inlet slit. The light incident from the inlet slit is irradiated to the diffraction grating, and only the light traveling in a specific direction out of the light wavelength-dispersed by the diffraction grating is taken out from the exit slit. By adjusting the rotation angle position of the diffraction grating to an appropriate position, monochromatic light of an arbitrary target wavelength (target wavelength) can be extracted (Patent Document 1). The rotation angle position of the diffraction grating is usually calculated based on an arithmetic expression with the wavelength as a variable. The calculation formula has parameters such as the spectroscopic deviation angle (the angle formed by the incident light and the outgoing light of the diffraction grating), the groove spacing of the diffraction grating, and the like, and is set for each spectroscope.

Japanese Unexamined Patent Publication No. 2013-253820

In such a spectroscope, an attachment error occurs when attaching an inlet slit, an outlet slit, a diffraction grating, a rotation drive mechanism, or the like to a housing. Therefore, in order to calibrate the mounting error, various adjustment work is performed before the product is shipped from the factory.

One of the adjustment works is the adjustment work of the optical axis of light whose wavelength is dispersed by a diffraction grating. This uses a He-Ne laser or the like as a light source, and the diffracted light of the laser light (in the case of a He-Ne laser, the wavelength is 632.8 nm) incident on the housing through the inlet slit passes almost through the center of the exit slit. As described above, it is a work of adjusting the inclination of the diffraction groove direction and the tilting direction (direction perpendicular to the direction of the diffraction groove) of the diffraction lattice. Specifically, a target member is installed just outside the entrance slit of the housing, and after visually confirming that the light from the light source is incident on the center of the target member, the target member is removed and the target member is removed. The light from the light source is incident on the housing through the inlet slit. Next, a target member is placed outside the exit slit of the housing, and the inclination of the diffraction grating in the tilting direction is adjusted while visually confirming that the 0th-order light is incident on the center of the target member. .. After that, the inclination of the diffraction grating in the groove direction is adjusted so that the primary diffracted light is incident on the center of the target member.

By the way, due to the high degree of freedom of handling, an optical fiber may be used for entering and exiting light to and from the housing. In this case, in a spectroscope incorporated in a device that does not require a large amount of light, a general-purpose optical fiber is connected to the housing using a general connector such as an FC connector or an SMA connector instead of an expensive bundle fiber. .. However, in the spectroscope that has undergone the optical axis adjustment work described above, when the optical fiber is connected to the outlet slit using a connector, the amount of primary diffracted light taken out from the outlet slit decreases, and the spectrophotometer is incorporated into the spectrophotometer. In that case, a sufficient amount of light may not be obtained in order to obtain a predetermined analysis accuracy and analysis sensitivity.

An object to be solved by the present invention is to enable the spectroscope to extract a sufficient amount of primary diffracted light at various wavelengths, not limited to the wavelength used for adjusting the optical axis.

The spectroscope according to the present invention made to solve the above problems is
A housing with an entrance and an exit,
A wavelength dispersion element arranged in the housing, which disperses the light incident from the inlet and emits the light of a target wavelength from the outlet.
A rotary drive mechanism that rotates the wavelength dispersion element,
A storage unit that stores an arithmetic expression for calculating the rotation angle position of the wavelength dispersion element corresponding to the target wavelength, and a storage unit.
The rotation drive mechanism is provided with a control unit for rotating the wavelength dispersion element so that the wavelength dispersion element is located at the rotation angle position calculated from the calculation formula.
In a state where the wavelength dispersion element is located at the rotation angle position calculated from the calculation formula with the first wavelength as the target wavelength, the wavelength when light including the light of the first wavelength is incident from the inlet. Calculated from the above formula with the second wavelength, which is a wavelength different from the first wavelength, that the optical axis of light from the dispersion element toward the outlet passes through the central predetermined range of the outlet and is different from the first wavelength. In a state where the wavelength dispersion element is located at the rotation angle position, when light containing the light of the second wavelength is incident from the inlet, the optical axis of the light from the wavelength dispersion element toward the outlet is the outlet. The wavelength dispersion element and the rotation drive mechanism are set in the housing so as to pass through the predetermined range.

Here, the light containing the light of the first wavelength and the light containing the light of the second wavelength may be either monochromatic light or multicolored light (multiwavelength light), and are directional light and omnidirectional light. Either is fine. Examples of the light having directivity include light that is mechanically imparted with directivity by using laser light, a slit, or the like. Further, the light containing the light of the first wavelength and the light containing the light of the second wavelength may be the same or different.

The spectroscope according to the present invention is obtained as follows.
In adjusting the optical axis before shipping the product from the factory, first, the first wavelength is set as the target wavelength. As a result, the rotation drive mechanism rotates the wavelength dispersion element so that the wavelength dispersion element is located at the rotation angle position corresponding to the first wavelength calculated from the calculation formula. Then, when light containing the light of the first wavelength is incident from the inlet in this state, the light is wavelength-dispersed by the wavelength-dispersing element, and the light of the first wavelength which is a part of the dispersed light is used. Since the light travels from the wavelength dispersion element toward the outlet, the arrangement of the wavelength dispersion element and the rotation drive mechanism is adjusted so that the optical axis of the light passes through a predetermined range in the center of the outlet. Subsequently, for the second wavelength, in the same procedure as for the first wavelength, the wavelength is such that the optical axis of the light of the second wavelength from the wavelength dispersion element toward the outlet passes through a predetermined range in the center of the outlet. Adjust the arrangement of the dispersion element and the rotation drive mechanism. At this time, even if the arrangement of the wavelength dispersion element and the rotation drive mechanism is not changed, when the optical axis of the light of the second wavelength dispersed by the wavelength dispersion element and heading toward the outlet passes through the predetermined range in the center of the outlet. , Finish the optical axis adjustment work. On the other hand, when the arrangement of the wavelength dispersion element and the rotation drive mechanism is changed when the second wavelength is set to the target wavelength, the first wavelength is set to the target wavelength again and the above-mentioned work is performed to perform the first operation. It is confirmed whether or not the optical axis of the light directed to the outlet is passed through the predetermined range of the outlet after the wavelength of the light is dispersed by the wavelength dispersion element. Then, when the optical axis of the light passes through the predetermined range of the outlet, the optical axis adjustment work is completed. In short, the optical axis adjustment work ends when it is confirmed that the light of the first and second wavelengths is dispersed by the wavelength dispersion element and both the light toward the outlet has passed through the predetermined range in the center of the outlet. ..

Here, the first wavelength and the second wavelength are preferably wavelengths that satisfy predetermined conditions. The predetermined conditions will be described later. Further, examples of the wavelength dispersion element include a diffraction grating and a prism. When the wavelength dispersion element is a diffraction grating, the optical axis adjustment work is the inclination of the diffraction grating in the groove direction and the direction perpendicular to the groove direction so that the optical axis of the primary diffraction light passes through a predetermined range in the center of the outlet. Therefore, the inclination in the direction along the lattice plane of the diffraction grating is adjusted. The fact that the optical axis of light from the wavelength dispersion element toward the outlet has passed a predetermined range in the center of the outlet means that a target member is placed near the outlet and the position of the light spot formed on the target member is visually confirmed. Alternatively, the amount of light emitted from a predetermined range of the outlet may be detected by a detector and confirmed by maximizing the amount of light.

In the spectroscope according to the present invention, when two different wavelengths are set as target wavelengths, the wavelength dispersive element and the wavelength dispersive element so that the optical axis of the light of the target wavelength from the wavelength dispersive element to the outlet passes through a predetermined range in the center of the outlet. Since the rotation drive mechanism is arranged, it is possible to extract a sufficient amount of light at various target wavelengths, not limited to the wavelength used for adjusting the optical axis.

The schematic block diagram which shows one Example of the spectroscope which concerns on this invention. The figure which shows the spot of the primary diffracted light near the exit slit. The graph which shows the size of the spot of the primary diffracted light formed in the vicinity of the exit slit when the laser beam of 200 nm diameter is incident on the housing through the inlet slit. The graph which shows the change of the intensity ratio of the 1st order diffracted light with respect to 0th order light by the difference of the optical axis adjustment method. A flowchart showing the procedure of adjusting the optical axis.

Hereinafter, an embodiment of the spectroscope according to the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of the spectroscope 100 of this embodiment. The spectroscope 100 is a mirror having a housing 1 having an inlet 11 and an outlet 12, a diffraction grating 2 as a wavelength dispersion element arranged inside the housing 1, a first reflecting surface 33, and a second reflecting surface 34. 3. It includes a rotation drive mechanism 5 for rotating the diffraction grating 2, an origin sensor 6 for detecting that the rotation position of the diffraction grating is at the machine origin position, a control unit 7, and an input unit 8.

The rotation drive mechanism 5 includes a stepping motor and a reduction mechanism for rotationally driving the diffraction grating 2 by decelerating the rotation of the output shaft of the stepping motor at a predetermined reduction ratio. The origin sensor 6 is composed of, for example, a reflection type photoelectric switch, and the protrusion (not shown) provided on the diffraction grating 2 detects that the diffraction grating 2 is located at the mechanical origin. The detection signal of the origin sensor 6 is output to the control unit 7.

Mounting mounts 13 and 14 are provided at the inlet 11 and the outlet 12 of the housing 1, respectively, and the inlet slit 131 and the outlet slit 141 are detachably mounted on each mount.

A filter device 9 is arranged in the vicinity of the outlet 12 in the housing 1. Although detailed illustration is omitted, the filter device 9 is attached to each of the disk 91, a plurality of openings arranged along the outer peripheral edge of the disk 91, and a plurality of openings other than one of the plurality of openings. It is provided with an optical filter 92 (only one optical filter is shown in FIG. 1), a rotation dial 93 for rotating the disk 91, and a rotation position sensor 94 for detecting the rotation position of the rotation dial 93. As the optical filter 92, a degree separation filter that transmits the first-order diffracted light from the diffraction grating 2 and cuts the higher-order light having a wavelength shorter than that of the first-order diffracted light is used. For the plurality of optical filters 92, order separation filters having different transmission wavelength bands are selected. The detection signal of the rotation position sensor 94 is output to the control unit 7. The rotary dial 93 is arranged on the outside of the housing 1, and the disk 91 is rotated by manually rotating the rotary dial 93, whereby an optical filter is placed on the optical path of light from the diffraction grating 2 toward the outlet 12. It is possible to switch between the state in which any of 92 is arranged and the state in which the opening is arranged.

The control unit 7 controls the operation of the rotation drive mechanism 5, and has a wavelength movement control unit 71, an initialization control unit 72, a coefficient setting unit 73, a coefficient storage unit 74, an arithmetic storage unit 75, and the like as functional blocks. Be prepared. The coefficient storage unit 74 stores the number of offset pulses C1 used for the initialization processing by the initialization control unit 72, the optical mount correction coefficient C2 and the filter correction coefficient C3 used for the wavelength movement processing by the wavelength movement control unit 71. Has been done. Further, the arithmetic expression storage unit 75 stores an arithmetic expression for calculating the number of driving pulses of the stepping motor required to rotate the diffraction grating 2 at the wavelength origin to the rotation angle corresponding to the target wavelength. .. This calculation formula is used for the wavelength movement processing by the wavelength movement control unit 71. The coefficient storage unit 74 and the arithmetic expression storage unit 75 correspond to the storage unit of the present invention.

The substance of the control unit 7 is a personal computer, and the functions of the respective function blocks are realized by operating the dedicated control software installed on the computer on the computer. Therefore, the input unit 8 includes a pointing device such as a keyboard and a mouse.

The number of offset pulses C1 is the number of drive pulses of the stepping motor required to move the diffraction grating 2 from the origin of the machine to the origin of the wavelength. The offset pulse number C1 is a value different for each device. The wavelength origin is the rotational position of the diffraction grating 2 assuming that the target wavelength is 0 nm.

The optical mount correction coefficient C2 and the filter correction coefficient C3 are used to calculate the number of pulses required to rotationally drive the diffraction grating 2 from the wavelength origin to the rotation position corresponding to the target wavelength. The optical mount correction coefficient C2 and the filter correction coefficient C3 are different values for each device. The filter correction coefficient C3 is a different value for each type of the optical filter 92, and the coefficient storage unit 74 stores the same number of filter correction coefficients C3 as the type of the optical filter 92 included in the disk 91.

The number of drive pulses of the stepping motor required to move the diffraction grating 2 from the wavelength origin to the rotation position corresponding to the target wavelength is calculated using the following calculation formula (1).
P = θ / Res ・ ・ ・ (1)
In the equation (1), P represents the number of drive pulses, θ (deg) represents the rotation angle of the diffraction grating 2 corresponding to the target wavelength, and Res (deg / pulse) represents the angular resolution of the diffraction grating 2.

Further, the rotation angle θ of the diffraction grating 2 is obtained from the following equation (2).
θ = {arcsin (K × (1 + C2) × W1) / π × 180} × C3 ・ ・ ・ (2)
In equation (2), K represents the optical mount constant and W1 represents the target wavelength. The optical mount constant K is a value peculiar to the apparatus, which is determined by the declination angle of the diffraction grating 2, the number of grooves, and the like. Further, in the equation (2), C2 and C3 represent the above-mentioned optical mount correction coefficient and filter correction coefficient, respectively.

The spectroscope 100 having the above configuration is subjected to work for adjusting the optical axis before being shipped from the factory. Hereinafter, the optical axis adjusting method will be described with reference to FIG. The optical axis adjustment work consists of a first step for obtaining two different wavelengths (first wavelength λ1 and a second wavelength λ2) used for optical axis adjustment, and two wavelengths (λ1, λ2) obtained in the first step. Includes a second step for adjusting the arrangement of the diffraction grating 2 and the rotation drive mechanism 5 using the above. In the optical axis adjusting work described below, the inclination of the diffraction grating 2 in the groove direction is mainly adjusted. Since the work of adjusting the inclination of the diffraction grating 2 in the tilting direction, which is performed prior to the work of adjusting the inclination of the diffraction grating 2 in the groove direction, is the same as the conventional one, the description thereof will be omitted.

(1) First Step First, the inlet slit 131 is removed from the mounting mount 13 at the inlet 11 of the housing 1, and a white light source such as a halogen lamp is connected to the mounting mount 13 via a single-core optical fiber. Then, the light emitted by the white light source is incident into the housing 1 through the single-core optical fiber. Further, the exit slit 141 is removed from the mounting mount 14 of the outlet 12 of the housing 1, and a photodiode array sensor (hereinafter referred to as “photo sensor”) is installed instead. Then, a plurality of wavelengths within the wavelength range of the light that can be emitted from the light source are set as target wavelengths, and while controlling the rotation drive mechanism 5 to rotate the diffraction grating 2, the first next time for each of the plurality of target wavelengths. An image of a spot on the light receiving surface of the photosensor of the diffraction grating is obtained (step 101). Next, the size of the spot is obtained from the image of the spot (step 102). The spot size may be determined by binarizing the image of the spot on the light receiving surface of the photo sensor to determine the shape of the spot and automatically calculating from the determined shape, and the image of the spot is displayed. It may be displayed on the screen and the size of the image may be measured manually.

FIG. 2 shows the sizes of spots of primary diffracted light obtained for a plurality of target wavelengths when light from a light source is incident on the housing 1 using a single-core optical fiber having a core diameter of 200 nm. There is. Further, FIG. 3 shows an image of a spot of the primary refraction light when the target wavelengths are set to 400 nm, 550 nm, 650 nm, 750 nm, and 800 nm. Here, the size of the spot means the length of the spot image shown in FIG. 3 in the vertical direction (spot height (mm)). The vertical direction of the spot image corresponds to the width direction of the grooves of the diffraction grating 2 (the direction in which the grooves are lined up). From FIGS. 2 and 3, it can be seen that the spot size differs depending on the target wavelength and that there are two minimum values in the wavelength range of 200 nm to 900 nm. The reason why the spot height differs depending on the target wavelength is that various aberrations exist in the optical system from the inlet 11 to the outlet 12, and the wavelength at which the spot height of the primary diffracted light is small is defined as the wavelength. Represents a wavelength with small astigmatism.

Based on the results obtained in step 102, the operator of the optical axis work can use any two different wavelengths included in the wavelength range of the light source (one of these two wavelengths is the first wavelength of the present invention and the other is. (Corresponding to the second wavelength) is selected as the wavelength for adjusting the optical axis. As the wavelength for adjusting the optical axis, it is preferable to select two wavelengths showing the minimum values in the graph of FIG. 3 for the reasons described below. That is, showing the minimum value in the graph of FIG. 3 means "satisfying a predetermined condition".

In the case of primary diffracted light with a small spot height near the outlet 12, the position of the optical axis when the spot does not overlap with the outlet 12 at all, and in the case of primary diffracted light with a large spot height near the outlet 12. Compared with the position of the optical axis when the spot does not overlap the outlet 12 at all, the primary diffracted light having a smaller spot height has a shorter distance from the central portion of the outlet 12. This means that the primary diffracted light having a small spot height cannot be emitted from the outlet 12 (that is, cannot be taken out from the spectroscope 100) even if the position of the optical axis is slightly deviated from the center of the outlet 12. Therefore, it means that the position of the optical axis needs to be adjusted strictly. Since it is necessary to rigorously adjust the optical axis of the primary diffracted light of the wavelength at which the spot height is the minimum value, if the optical axis is adjusted using the primary diffracted light of such a wavelength, the optical axis can be adjusted. Not limited to the wavelength used, the primary diffracted light in a wide wavelength range can be extracted from the outlet 12.

However, one of the two wavelengths for adjusting the optical axis may be set to a wavelength showing a minimum value (minimum wavelength), and a wavelength different from the minimum wavelength may be selected as the other wavelength. For example, when there are two minimum wavelengths and the values of the two minimum wavelengths are close to each other, one of the two wavelengths for adjusting the optical axis is set as the minimum wavelength and the other is the wavelength range of the light source. The wavelength should be near the end of.

(2) Second Step Two wavelengths selected as wavelengths for adjusting the optical axis in the first step are set as target wavelengths (step 103). Then, while controlling the rotation drive mechanism 5 to rotate the diffraction grating 2, the amount of light whose primary diffracted light is incident on a predetermined range of the light receiving surface of the photosensor is detected for each of the two target wavelengths (step). 104). The process of step 104 is repeated while changing the arrangement of the diffraction grating 2 and the rotation drive mechanism 5 with the diffraction grating 2 positioned at the rotation angle position corresponding to the target wavelength. As a result, the inclination of the diffraction grating 2 in the groove direction is adjusted so that the amount of light detected by the photo sensor is maximized. In this case, it is preferable that the detected light amount of the photosensor is maximized at both of the two wavelengths for adjusting the optical axis, but the total value of the detected light amounts of the photosensors obtained at the two wavelengths can be maximized. For example, the amount of detected light at one or both wavelengths does not have to be the maximum value.

Using the spectroscope 100 after the optical axis adjustment is performed by the above method, the light emitted from the white light source is incident on the housing 1, and the rotation drive mechanism 5 is controlled to rotate the diffraction grating 2. The results obtained when the amount of the primary diffracted light of each of the plurality of target wavelengths is detected are shown in FIG. Here, the two minimum wavelengths in the graph shown in FIG. 2 are defined as wavelengths for adjusting the optical axis. In addition, FIG. 4 also shows the result of detecting the amount of light of the first-order diffracted light in the same manner using a conventional spectroscope whose optical axis is adjusted with the first-order diffracted light of one wavelength. The horizontal axis of FIG. 4 represents the target wavelength (nm), and the vertical axis represents the ratio of the amount of light of the first-order diffracted light to the amount of light of the 0th-order light. As can be seen from this figure, the spectroscope of this embodiment has an increased amount of primary diffracted light as compared with the conventional spectroscope.

In the above description, the light source used in the first step (the step of obtaining the wavelength for adjusting the optical axis) and the light source used in the second step (the optical axis adjusting step) are the same, but in the second step, the optical axis is adjusted. A laser that emits laser light (monochromatic light) in the vicinity of the wavelength for use may be used as a light source.
Further, in the optical axis adjusting work, not only the arrangement of the diffraction grating 2 and the rotation driving mechanism 5 but also the posture of the mirror 3 (the inclinations of the first and second reflecting surfaces 33 and 34) may be adjusted.

Further, in the above-mentioned optical axis adjustment method, the amount of light emitted from the outlet 12 of the housing 1 is measured by a photosensor, but a single-core optical fiber having a predetermined core diameter is attached to the mounting mount 14 of the outlet 12. The arrangement of the diffraction grating 2 and the rotation drive mechanism 5 may be adjusted so that the result of connecting and detecting the amount of light passing through the light amount with the detector is maximized. In this example, the core of the optical fiber corresponds to a predetermined range in the center of the outlet 12. Further, a target member is installed near the outlet 12, and the diffraction grating 2 and the rotation drive mechanism 5 are arranged so that the spot of the primary diffracted light formed on the target member is located within a predetermined range in the center of the target member. You may adjust.

It is clear that the above embodiment is merely an example of the present invention, and is included in the present invention even if it is appropriately modified, added, deleted, etc. within the scope of the claims of the present application.

[Various aspects]
It will be understood by those skilled in the art that the above-described exemplary embodiments are specific examples of the following embodiments.

(Clause 1) The spectroscope according to the present invention is
A housing with an entrance and an exit,
A wavelength dispersion element arranged in the housing, which disperses the light incident from the inlet and emits the light of a target wavelength from the outlet.
A rotary drive mechanism that rotates the wavelength dispersion element,
A storage unit that stores an arithmetic expression for calculating the rotation angle position of the wavelength dispersion element corresponding to the target wavelength, and a storage unit.
The rotation drive mechanism is provided with a control unit for rotating the wavelength dispersion element so that the wavelength dispersion element is located at the rotation angle position calculated from the calculation formula.
In a state where the wavelength dispersion element is located at the rotation angle position calculated from the calculation formula with the first wavelength as the target wavelength, the wavelength when light including the light of the first wavelength is incident from the inlet. Calculated from the above formula with the second wavelength, which is a wavelength different from the first wavelength, that the optical axis of light from the dispersion element toward the outlet passes through the central predetermined range of the outlet and is different from the first wavelength. In a state where the wavelength dispersion element is located at the rotation angle position, when light containing the light of the second wavelength is incident from the inlet, the optical axis of the light from the wavelength dispersion element toward the outlet is the outlet. The wavelength dispersion element and the rotation drive mechanism are set in the housing so as to pass through the predetermined range.

According to the spectroscope according to the first item, when two different wavelengths are set as target wavelengths, the optical axis of light of each target wavelength from the wavelength dispersion element to the outlet passes through a predetermined range in the center of the outlet. Since a wavelength dispersion element and a rotation drive mechanism are arranged in the wavelength, in a configuration in which an optical fiber is connected to an outlet and light is emitted through the optical fiber, the wavelength is not limited to the wavelength used for the optical axis adjustment, and various target wavelengths are used. It is possible to extract a sufficient amount of light.

(Item 2) In the spectroscope according to the item 1, the wavelength dispersion element is a diffraction lattice, and the first wavelength is a plurality of wavelengths within a wavelength range of multi-wavelength light including light of the first wavelength. When the multi-wavelength light is incident from the inlet in a state where the diffraction grid is located at the rotation angle position calculated from the calculation formula with each of the wavelengths of It can be the wavelength at which the size of the cross section of the primary diffracted light at the outlet is minimized.

(Item 3) In the spectroscope according to the first item, the wavelength dispersion element is a diffraction lattice, and the first wavelength and the second wavelength are the light of the first wavelength and the second wavelength. The multi-wavelength light is used in a state where the diffraction lattice is located at a rotation angle position calculated from the above calculation formula with each of three or more wavelengths within the wavelength range of the multi-wavelength light including the light of the wavelength as the target wavelength. It can be the wavelength at which the size of the cross section of the primary diffracted light from the diffractive grid toward the outlet when incident from the inlet is the first and second smallest.

The size of the cross section of the primary diffracted light from the diffraction grating toward the outlet means the area of the cross section, the length of a predetermined portion (diameter, perimeter) of the cross section, and the like. The closer the image formation position of the first-order diffracted light is to the exit, the smaller the size of the cross section. Compared to the primary diffracted light having a large cross section, the primary diffracted light having a small cross section may not be able to pass through the outlet even if the amount of deviation between the optical axis and the center of the outlet is small. The position needs to be adjusted precisely. In the spectroscopes described in the second and third paragraphs, since the optical axis is adjusted by using the primary diffracted light having a wavelength that makes the cross section at the outlet smaller, even if the spectroscope is connected to the outlet, an optical fiber is connected. , It is possible to reliably extract a sufficient amount of primary diffracted light from the optical fiber at various wavelengths.

1 ... Housing 11 ... Inlet 12 ... Outlet 13a ... Inlet slit 14a ... Exit slit 2 ... Diffraction grating 5 ... Rotational drive mechanism 7 ... Control unit 74 ... Coefficient storage unit 75 ... Calculation type storage unit 8 ... Input unit 100 ... Spectrometer

Claims (3)

A housing with an entrance and an exit,
A wavelength dispersion element arranged in the housing, which disperses the light incident from the inlet and emits the light of a target wavelength from the outlet.
A rotary drive mechanism that rotates the wavelength dispersion element,
A storage unit that stores an arithmetic expression for calculating the rotation angle position of the wavelength dispersion element corresponding to the target wavelength, and a storage unit.
The rotation drive mechanism is provided with a control unit for rotating the wavelength dispersion element so that the wavelength dispersion element is located at the rotation angle position calculated from the calculation formula.
In a state where the wavelength dispersion element is located at the rotation angle position calculated from the calculation formula with the first wavelength as the target wavelength, the wavelength when light including the light of the first wavelength is incident from the inlet. Calculated from the above formula with the second wavelength, which is a wavelength different from the first wavelength, that the optical axis of light from the dispersion element toward the outlet passes through the central predetermined range of the outlet and is different from the first wavelength. In a state where the wavelength dispersion element is located at the rotation angle position, when light containing the light of the second wavelength is incident from the inlet, the optical axis of the light from the wavelength dispersion element toward the outlet is the outlet. A spectroscope in which the wavelength dispersion element and the rotation drive mechanism are set in the housing so as to pass through the predetermined range. In the spectroscope according to claim 1,
The wavelength dispersion element is a diffraction grating,
The diffraction lattice is located at a rotation angle position calculated from the above calculation formula with each of a plurality of wavelengths within the wavelength range of the multi-wavelength light including the light of the first wavelength as target wavelengths. A spectroscope that is the wavelength at which the area of the cross section of the primary diffracted light from the diffractive lattice toward the outlet is minimized when the multi-wavelength light is incident from the inlet in the state. In the spectroscope according to claim 1,
The wavelength dispersion element is a diffraction grating,
The first wavelength and the second wavelength have each of three or more wavelengths within the wavelength range of the multi-wavelength light including the light of the first wavelength and the light of the second wavelength as target wavelengths. The area of the cross section of the primary diffracted light from the diffractive lattice toward the outlet when the multi-wavelength light is incident from the inlet in a state where the diffractive lattice is located at the rotation angle position calculated from the calculation formula. Is the wavelength when is the first and second smallest, the spectroscope.

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