JP2002257509A - Interferometer adjustment method, interferometer used for implementing the adjustment method, and processing program for implementing the adjustment method - Google Patents

Abstract

(57) [Problem] To provide a small and stable interferometer with reduced cost. An interferometer including an optical system having a plane mirror having a plurality of operating degrees of freedom dependent on each other, when adjusting the amount of operation of the plane mirror at each of the plurality of degrees of operation, the optical system. Detecting output light from a system at a predetermined position, and adjusting an operation amount at each of the plurality of degrees of freedom so that the output light is optimized by a genetic algorithm based on an evaluation of the detected output light. It is.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an interferometer used for an infrared spectrophotometer (FTIR) or the like, and more particularly to an optical system having a plane mirror having a plurality of operating degrees of freedom dependent on each other. The present invention relates to an interferometer adjustment method, an interferometer used for implementing the adjustment method, and a processing program for implementing the adjustment method.

[0002]

2. Description of the Related Art In recent years, attention has been paid to environmental problems, and chemical analyzers used for measuring chemical substances have been required to have stability along with their miniaturization and portability. ing. That is, conventional analytical instruments have been generally designed in consideration of indoor measurements where there is little change in the measurement environment. However, in recent years, attention has been paid to environmental issues, and it is required to be able to perform in-situ measurement at a measurement place, and a small and portable analyzer is desired. The most widely used analytical instrument is an infrared spectrophotometer (FTIR), which is capable of identifying and quantifying most chemical substances and is capable of trace analysis, so it is important in environmental analysis. The advantages of downsizing and portability of FTIR are great.

The FTIR is an interferometer using infrared light as a light source. As shown in FIG.
It comprises a sample chamber 3, a detector 4, a data processing section 5, and a record display section 6. Since most parts are structurally occupied by the interferometer and the adjustment points are concentrated on the interferometer, the FT
For miniaturization and portability of IR, miniaturization and stabilization of the interferometer are required.

An interferometer used for FTIR is called a Michelson interferometer, and basically has a structure as shown in FIG. A light beam emitted from the light source S is split into two by a beam splitter BS, one of which travels straight to a fixed reflecting mirror M2 and the other travels straight after being reflected by a movable reflecting mirror M1. The light beams reflected by the respective mirrors return to the BS, are combined, and travel to the detector P. At this time, interference of the combined light occurs due to the optical path difference (distance difference) between BS-M2 and BS-M1. For example, as shown in FIG. 12A, if the optical path difference is an integral multiple of the wavelength of light, two lights (L1, L2) without deviation are combined to enhance each other (L3). . On the other hand, the moving mirror M1 moves, and as shown in FIG. 12B, the optical path difference is a half integral multiple of the wavelength of light (integer plus / minus 1/2 wavelength).
If, the shifted lights (L1, L2 ') are combined to cancel each other (L3').

The interferometer generates an optical interference wave by adjusting the optical path difference, and the FTIR can obtain a spectrum by performing Fourier transform on an interferogram obtained by the interferometer. To increase the accuracy of this interferometer,
It is necessary to adjust the interference light in wavelength units, and it is important to adjust the position and angle of the reflecting mirror (fixed mirror, movable mirror).

A number of interferometers have been developed so far. Here, an early type interferometer and a commercially available FTIR
An outline of a compensating interferometer that is frequently used in the present invention will be described, and problems to be solved by the invention will be described.

In the early type interferometer, a plane mirror was used as the reflection mirrors M1 and M2. Therefore, due to the structure of the interferometer, unless the plane mirror is perpendicular to the optical axis of the interferometer, the incident light and the reflected light are not parallel, and it is not possible to obtain an interfering composite wave.
Therefore, it is necessary to adjust the plane mirror, and an interferometer such as FTIR, which requires accuracy in wavelength units, requires high-precision adjustment. As shown in FIG.
The degree of freedom in PM adjustment is one degree of freedom (z) in the optical axis direction,
There are two degrees of freedom (θx, θy) in the direction of rotation about axes (x, y) in two directions perpendicular to the optical axis, for a total of three degrees of freedom.

[0008] The compensation interferometer replaces the plane mirror of the initial interferometer with a Littrow mirror, and in particular, a commercially available FTIR replaces a corner cube mirror. The corner cube mirror is a mirror that can obtain reflected light parallel to the incident light regardless of the incident light. When light enters a corner cube mirror CM having three mutually perpendicular surfaces F1 to F3 as shown in FIG. , Parallel light is reflected regardless of the angle. Therefore, if the vertex of the corner cube mirror CM is included in the light beam, parallel reflected light can be obtained without depending on the angle. Therefore, there is no need to adjust the angles (θx, θy) as in a plane mirror, and there is a total of three degrees of freedom, one degree of freedom (z) in the optical axis direction and two degrees of freedom (x, y) in the direction perpendicular to the optical axis. Adjustment. A system in which an automatic alignment function is mounted on this corner cube mirror interferometer has been disclosed in Japanese Patent Application Laid-Open No. Hei 10-206133. FTIR using this interferometer is
Commercially available from JASCO Corporation.

In the early interferometers, the adjustment of the reflecting mirror is performed by a technician, and most of the commercially available FTIRs are shipped without alignment (no adjustment is required). rare. However, in recent years, a device that can replace the beam splitter BS has been desired in response to a wide range of analysis requirements such as environmental problems. By exchanging the beam splitter BS, the measurable wavelength range can be extended. Therefore, in both the plane mirror type and the corner cube mirror type interferometer, it was necessary to readjust the reflecting mirror when the beam splitter BS was replaced. In addition, in order to enable portability, it was thought that readjustment was necessary due to transportation and environmental changes. Also, in view of cost and labor, there has been a demand for an automatic alignment (automatic adjustment) that can be easily re-adjusted by any manufacturer or user, instead of an adjustment method by a technician.

[0010] The interferometer is adjusted to obtain the maximum output of the interference light. In the automatic alignment, the maximum value of the intensity of the interference light output is obtained according to a given search algorithm using the degree of freedom of the reflecting mirror as a variable. As a search algorithm, a hill-climbing method is generally used. As for a corner cube mirror interferometer, a search algorithm using a simplex method has been proposed in Japanese Patent Application Laid-Open No. 10-206133.

The simplex method disclosed in Japanese Patent Application Laid-Open No. 10-206133 is suitable for a unimodal search as shown in FIG. 15 because it searches for a variable in the maximum inclination direction of the interference light output. However, in a multimodal search in which a large number of local peaks exist as shown in FIG. 16, the search ends at the local peak, so that a true peak cannot be reached. Therefore, it can be applied to adjustment (unimodality) having no dependency between the degrees of freedom variables using the corner cube mirror CM, but three adjustment drive elements DE1 proposed by the inventor of the present application as exemplified in FIG. This simplex method cannot be applied to an interferometer using a plane mirror PM that has a dependency between variables having degrees of freedom because it is driven by ~ DE3, or an interferometer that requires complicated adjustment (multimodality). .

That is, the algorithms of the hill-climbing method and the simplex method are suitable for adjustment in an independent relationship in which a large number of degrees of freedom move independently and do not affect each other. However, as shown in FIG. However, it is not suitable for adjusting a plane mirror PM having a dependency between variables having degrees of freedom (having a plurality of operating degrees of freedom dependent on each other). Many interferometers use corner cube mirrors to improve stability, but corner cube mirrors are much more expensive than plane mirrors, and they require a large space because they are deep mirrors. I do.

SUMMARY OF THE INVENTION Therefore, the present invention provides an interferometer having a simple structure including an optical system having a plurality of plane mirrors having a plurality of operating degrees of freedom dependent on each other in order to realize a small and stable interferometer with reduced cost. And an automatic alignment (automatic adjustment) method for compensating for the stability of the interferometer, and a processing program for implementing the adjustment method.

[0014]

An interferometer adjusting method according to the present invention, which advantageously solves the above-mentioned problems, comprises an optical system having a plane mirror having a plurality of operating degrees of freedom dependent on each other. When adjusting the amount of operation of the plane mirror in each of the plurality of degrees of freedom of operation,
Detecting the output light from the optical system at a predetermined position, and adjusting the operation amount at each of the plurality of degrees of freedom so that the output light is optimized by a genetic algorithm based on the evaluation of the detected output light. It is characterized by doing.

According to this adjustment method, the interferometer having an optical system having a plurality of plane mirrors having a plurality of operation degrees of freedom dependent on each other adjusts the operation amount of the plane mirror in each of the plurality of operation degrees of freedom. In doing so, the output light from the optical system is detected at a predetermined position, and based on the evaluation of the detected output light, a genetic algorithm, which is an effective algorithm for optimizing a plurality of nonlinear adjustment points in a short time, An inexpensive and compact plane mirror with inexpensive and simple adjustment means that provides multiple degrees of freedom of operation that are dependent on each other because the amount of operation at each of the multiple degrees of freedom is adjusted to optimize the output light. The interferometer with a mirror can automatically adjust the amount of operation of the plane mirror in each operating degree of freedom in a relatively short time to optimize the output light, realizing a compact, stable and inexpensive interferometer. Do Door can be.

In the adjusting method according to the present invention, the adjustment of the amount of operation at each of the plurality of degrees of freedom is performed by adjusting and driving a central portion, an upper or lower portion, and a side portion of the plane mirror. In this case, only three adjustment driving operations of the plane mirror are required, so that the adjustment driving means and the entire interferometer can be configured simply and compactly.

In the adjusting method of the present invention, the amount of operation in each of the plurality of degrees of freedom may be further finely adjusted by a hill-climbing method based on the evaluation of the detected output light. By doing so, the time required for adjusting the operation amount can be further reduced.

Further, in the adjusting method of the present invention,
The detection of the output light may be performed at a central portion, an upper portion or a lower portion, and a side portion of the detection board disposed at a predetermined position of the interferometer. Position and angle deviation can be easily detected.

In the adjusting method of the present invention,
The detection of the output light may be performed at two places where the distance from the central part is different for each of the upper part or the lower part and the side part. It can be detected in detail.

The interferometer of the present invention used for carrying out the adjusting method may be an interferometer having an optical system having a plane mirror having a plurality of operating degrees of freedom dependent on each other. An output light detecting means for detecting light at a predetermined position, and a plane mirror adjusting drive means for adjusting and driving the plane mirror with the plurality of degrees of freedom of operation.

According to such an interferometer, the output light detecting means detects, at a predetermined position, output light from an optical system of the interferometer having a plane mirror having a plurality of operating degrees of freedom dependent on each other. Since the plane mirror adjustment driving means adjusts and drives the plane mirror with the plurality of degrees of freedom of operation, based on the detection result of the output light detection means, controlling the operation of the plane mirror adjustment driving means by the adjustment method, A simple, compact, and inexpensive interferometer can be realized.

In the interferometer according to the present invention, each of the plurality of degrees of freedom of operation of the plane mirror adjustment driving means is determined by the genetic algorithm based on the evaluation of the output light detected by the output light detection means. It is possible to provide an operation amount adjusting means for adjusting the output light so as to optimize it. In this way, the automatic adjustment of the plane mirror can be performed at any time and anywhere without separately preparing such an operation amount adjusting means. It can be performed.

Further, in the interferometer of the present invention, the plane mirror adjustment drive means has three adjustment drive elements for adjusting and driving the central part, the upper or lower part, and the side part of the plane mirror. In this case, the adjustment driving means for adjusting and driving the plane mirror, and thus the entire interferometer, can be simply and miniaturized.

Further, in the interferometer according to the present invention, the operation amount adjusting means may finely adjust each of the plurality of degrees of operation of the plane mirror adjustment driving means by a hill-climbing method. By doing so, the time required for adjusting the operation amount can be further reduced.

Further, in the interferometer of the present invention, the output light detecting means has a light receiving element at a central portion, an upper or lower portion, and a side portion of a detection board disposed at a predetermined position of the interferometer. If you do this,
The deviation of the position and angle of the plane mirror can be easily detected from the state of the interference fringes.

Further, in the interferometer according to the present invention, the output light detecting means has two light receiving elements having different distances from the light receiving element at the central part, respectively, at the upper or lower part and at the side part. In this case, the state of the interference fringes can be detected in more detail.

The processing program of the present invention for implementing the interferometer adjustment method includes a step of evaluating the detected output light, and a step of optimizing the output light by a genetic algorithm based on the evaluation of the output light. Adjusting the amount of actuation in each of the plurality of degrees of freedom so that
Is executed by a computer.

According to such a processing program, the step of evaluating the detected output light and the step of evaluating each of the plurality of degrees of freedom of operation are performed so that the output light is optimized by a genetic algorithm based on the evaluation of the output light. And the step of adjusting the amount of operation of the computer, the interferometer having an inexpensive and small plane mirror with an inexpensive and simple adjusting means that provides a plurality of degrees of freedom of operation that are dependent on each other, The amount of operation of the plane mirror in each degree of freedom of operation can be automatically adjusted in a relatively short time so that the output light is optimized, and a small, stable and inexpensive interferometer can be realized.

[0029]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a schematic diagram showing the configuration of an embodiment of the interferometer of the present invention used in an embodiment of the interferometer adjusting method of the present invention, and is the same as FIG. 11 in FIG. Are indicated by the same reference numerals. That is, the interferometer of this embodiment has a structure in which the light source S and the detector P are disposed between the light source S and the detector P, similarly to the interferometer shown in FIG.
An optical system O having two reflecting mirrors and a beam splitter is provided, and a planar mirror is used as each of the two reflecting mirrors in the optical system O in order to reduce costs.

The fixed mirror of the two plane mirrors is not an adjustment driving device in which linear driving devices are three-dimensionally stacked and arranged as plane mirror adjustment driving means, but one of the plane mirrors PM as shown in FIG. Is provided with a simple adjustment drive device in which three adjustment drive elements DE1 to DE3 which expand and contract by the expansion and contraction of the piezo element are concentrated. Such an adjustment drive has a subordinate structure. The characteristics of the substructure will be described in detail below. In addition, this structure does not require a large space, so that the interferometer is downsized.

The independent structure means a driving device for adjusting the position z in the optical axis (z-axis) direction, the angle around the x-axis (vibration) θx, and the angle around the y-axis (tilt) θy as in the case of the plane mirror PM shown in FIG. 14, a structure of an adjustment driving device for an x, y-axis direction position x, y orthogonal to the optical axis, such as for a corner cube mirror CM shown in FIG. It has become. This structure is the most common and widely used. On the other hand, in a subordinate structure such as the adjustment driving device of the embodiment shown in FIG. 2 or the adjustment driving device shown in FIG. 17, the position z in the optical axis (z-axis) direction and the shake θ
Since each of the adjustment driving elements DE1 to DE3 of x and tilt θy is arranged on one side of the plane mirror PM as shown in the figure, the structure is simple, but the influence is caused when these adjustment driving elements are moved. May be mutually exclusive.

That is, by operating the adjustment drive elements DE2 and DE3 with the adjustment drive element DE1 as a reference point, the shake θy and the tilt θx can be adjusted respectively. However, the adjustment drive element DE1 also operates at the reference point, so that a dependent relationship is established. For example, it is assumed that the operation amounts of the adjustment drive elements DE1 to DE3 are all 0. Thereafter, assuming that the adjustment drive element DE2 has moved by an operation amount of 5
It swings to the right by y (5), but then adjust drive element DE1
When DE3 moves by an operating amount of 5, the operating amounts of the adjustment drive elements DE1 to DE3 all become 5, and the vibration is eliminated. Actuation of the adjustment drive element DE1 changes the angle of the shake and the tilt, so that it is dependent.

The interrelationship between the three operation amounts for optimal adjustment of these is linear in an independent structure and non-linear in a subordinate relationship.
Then, it is necessary to select an adjustment method suitable for the structure of the adjustment drive device.

In the interferometer of the above embodiment, a plane mirror and
Since the adjustment driving device having the dependent structure having the adjustment driving elements DE1 to DE3 is employed, it is necessary to perform nonlinear adjustment. Therefore, the adjustment method of this embodiment employs a search algorithm that uses a genetic algorithm that is an effective algorithm for optimizing a plurality of nonlinear adjustment points in a short time and a hill-climbing method that is a conventional method. . In this search algorithm, the output of the interference waveform is adjusted by feeding back the signal. Therefore, as shown in FIG. 1, a detection board PB for self-evaluation and its detection board are provided inside the interferometer of the above embodiment. The half mirror HM for splitting the output light of the optical system O is incorporated in the gate PB.

In the automatic alignment using the genetic algorithm in the adjustment method of the above embodiment, the optimum adjustment is performed by feeding back the evaluation information of the interference light which is the output light of the optical system O. Therefore, it is necessary to detect interference light for auto alignment,
In the interferometer of the above embodiment, the output light of the infrared interference light is converted from the light intensity to the electric signal by the silicon photodiode PD provided on the detection board PB, and the ordinary personal computer as the operation amount adjusting means is used. The signals are input to a PC and fed back to the three adjustment drive elements DE1 to DE3 via channels 1 to 3 (ch) as shown in FIG. 2 through the personal computer PC. Here, the arrangement of the silicon photodiode PD provided on the detection board PB is, as shown in FIG. 3, the output detection at the center (3 channels (ch)),
There are a total of five locations (five channels): output detection at the top × 2 (1, 2 channels (ch)) and output detection at one side × 2 (4, 5 channels (ch)).

Therefore, the interferometer of the above embodiment is not shown in FIG. 1, as is apparent from FIG. 1; the light source S, the plane mirror interferometer optical system O, the detector P, and the optical system O and the detector P. In addition to the sample chamber, it comprises a half mirror HM, a detection board PB for auto alignment, a personal computer PC, and adjustment drive elements DE1 to DE3 for adjusting a fixed mirror which is one of the plane mirrors in the optical system O. I have.

FIG. 4 shows the flow of the adjustment method of the above embodiment. Here, after the interferometer is activated in step S1,
Calibration is performed in step S2, and then, in step S3, the optimal adjustment solution of the plane mirror is searched in a wide range by a genetic algorithm (GA), and the best individual obtained as a result is used in step S4 by a hill-climbing method. Tweak. According to this method, the GA that specializes in broad and coarse multimodal search and the hill-climbing method that specializes in narrow and fine unimodal search are used together, realizing autoalignment that is multimodal search with high accuracy. can do.

FIGS. 5 to 7 show the flow of processing by the genetic algorithm performed by the personal computer PC in step S3. In FIG. 5, first, in step S11, each degree of freedom of operation (each adjustment drive element DE1) is used as genetic information of an individual.
DEDE3), an initial population of parent individuals having real values of the working amount is generated, and in the next step S12, the parent individuals in the initial population are evaluated. In the following steps S13 to S15, the characteristics of the genetic algorithm are used. A process of selecting a plurality of individuals, crossing the selected individuals, and mutating the crossed individuals is performed to generate a population of offspring individuals.
Then, each child individual of the group is evaluated, and the next step S
In 17, the child individuals are replaced with the previous parent individuals, and in the next step S 18, it is determined whether or not the evaluation value has exceeded the target value. If not, the process returns to step S 13 and returns to step S 13. If so, the process ends.

FIG. 6 shows the evaluation process in steps S12 and S16. First, in step S21, the genetic information of the individual (the actual value of the amount of operation for each degree of freedom) is shown in FIG. In step S22, a plane mirror (fixed mirror) is adjusted based on the genetic information of the individual element, and in step S22, the operation of one of the adjusted drive elements DE1 to DE3 that has been activated is completed. Then, the apparatus waits for a predetermined period of time to stabilize the output of the interference light, and then proceeds to the next step S
At 23, the interference intensity of the interference light detected by the detection board PB, which is obtained from the output signals from the five silicon photodiodes PD of the detection board PB, is input to the personal computer PC as shown in FIG. It is evaluated by an evaluation method and is used as an evaluation value of the individual.

FIG. 7 shows the replacement process in step S17, in which replacement is started in step S31.
In the next step S32, the top two individuals C and D with the highest evaluation are selected from the selected parent individuals A and B and the generated child individuals A 'and B', and in the next step S33 the parent individuals A and B are selected. The individuals A and B are replaced with the individuals C and D, and the replacement is completed in the next step S34.

The details of the processing of the crossover of the selected individuals and the mutation of the crossed individuals in steps S14 and S15 are described in, for example,
Since it is publicly known as disclosed in Japanese Patent Publication No. 0-156627, the description is omitted here. On the other hand, in this embodiment, the process of selecting a plurality of individuals in step S13 is a process of randomly selecting two parent individuals A and B from the population, and performing a genetic operation on these.

In the evaluation method described below, the symbols shown in FIG. 3 are used. That is, the central part of the detection board PB is 3ch, the upper part is 1ch, 2ch, and one side is 4ch, 5c.
h. In the first example of the evaluation method, the sum of 3ch and 1ch and 5ch farther from the center is used as the evaluation value. In the second example of the evaluation method, the sum of 3ch and 2ch and 4ch near the center is used as the evaluation value. In the third example of the evaluation method, the sum of 3ch, 1ch, 2ch, 4ch, and 5ch is used as the evaluation value.

In a fourth example of the evaluation method, in order to evaluate the distortion of the interference fringes, the absolute value of the difference between 1ch and 5ch far from the center is calculated, and the value obtained by subtracting the absolute value from 3ch is used as the evaluation value. And In the fifth example of the evaluation method, in order to evaluate distortion of interference fringes, the absolute value of the difference between 2ch and 4ch near the center is calculated, and a value obtained by subtracting the absolute value from 3ch is used as the evaluation value. In the sixth example of the evaluation method, the absolute value of the difference between 1ch and 5ch far from the center and the absolute value of the difference between 2ch and 4ch near the center are evaluated in order to evaluate the interference fringe distortion. Is calculated, and a value obtained by subtracting them from 3ch is set as an evaluation value.

Generally, the light output tends to be higher at a position closer to the center of the detection board PB. Therefore, the fourth example is the most preferable. However, the above-mentioned evaluation methods are selectively used depending on the size of the interference light and the like. May be.

Finally, FIG. 8 shows the flow of the fine adjustment processing by the hill-climbing method performed by the personal computer PC in step S4. In this hill-climbing method, fine adjustment is performed in a small search space centered on the best individual previously searched by a genetic algorithm (GA). That is, here, first, in step S41, the best individual A obtained by GA is selected, and then, in step S42, as shown in FIG. On the other hand, ± δ is applied to each of them to generate new 6 individuals (3 degrees of freedom × 2).

Then, in the next step S43, the six individuals are evaluated as described above.
At 45, the seven evaluation values combined with the original individual are compared. If the best one A ′ among the new six individuals is better than the original best individual A, the original best individual A is replaced with the new best individual A at step S46. The operation of replacing with the individual A 'is repeatedly performed, and when the original individual has the highest evaluation, the original individual is set as the final adjustment result.

According to the interferometer of this embodiment and the method of adjusting the interferometer, each of the three operating degrees of freedom of the interferometer having the optical system O having a plane mirror having three operating degrees of freedom dependent on each other is described. When adjusting the operation amount of the plane mirror in the above, the silicon-photodiode of the detection board PB in which the output light from the optical system O is arranged at a predetermined position of the interferometer
Based on the evaluation of the output light detected by the PD, based on the evaluation of the detected output light, the output light is optimized so that the output light is optimized by a genetic algorithm that is an effective algorithm for optimizing multiple nonlinear adjustment points in a short time. Adjust the amount of operation in each of the three degrees of freedom for position, runout and tilt,
Even in an interferometer having an inexpensive and small plane mirror with an inexpensive and simple adjusting drive that provides three degrees of freedom dependent on each other, the amount of operation of the plane mirror in each degree of freedom of operation can be relatively short. The output light can be automatically adjusted so as to be optimized, and a small, stable and inexpensive interferometer can be realized.

Further, according to the interferometer of this embodiment and the method of adjusting the same, the adjustment of the amount of operation at each of the three degrees of freedom of operation can be performed by adjusting the central portion, the upper portion, and the side portions of the fixed plane mirror. Since adjustment driving is performed by the driving elements DE1 to DE3, adjustment driving at three points of the plane mirror is sufficient, so that the adjustment driving device and the entire interferometer can be simply and miniaturized.

According to the interferometer of this embodiment and the method of adjusting the same, the amount of operation at each of the three degrees of freedom is determined based on the evaluation of the output light detected by the silicon photodiode PD of the detection board PB. Since the fine adjustment is performed by the hill-climbing method, the time required for adjusting the operation amount can be further reduced.

Further, according to the interferometer of this embodiment and the method of adjusting the same, the detection of the output light is performed at the central portion, the upper portion, and one side portion of the detection board PB disposed at a predetermined position of the interferometer. Therefore, it is possible to easily detect the deviation of the position and angle of the plane mirror from the state of the interference fringes.

According to the interferometer of this embodiment and the method of adjusting the same, the output light is detected at two locations at different positions from the center for each of the upper and side portions. Therefore, the state of interference fringes can be detected in more detail.

Although the present invention has been described with reference to the illustrated examples, the present invention is not limited to the above examples. For example, the interferometer itself includes an operation amount adjusting means constituted by a microcomputer or the like. In addition, the operation amount adjusting means may meet a computer shared with the data processing unit of the infrared spectrophotometer, and the detection board may serve as a light receiving element other than a silicon-photodiode, such as a two-dimensional light receiving element. May be provided. Further, an adjustment driving device having the configuration shown in FIG. 17 may be used as the plane mirror adjustment driving means, and the degree of freedom of operation of the plane mirror adjustment driving means may be appropriately increased. The interferometer and the method for adjusting the interferometer according to the present invention can be used other than the infrared spectrophotometer.

The present invention further includes a processing program for implementing an interferometer adjustment method, the processing program comprising: a step of evaluating a detected output light; and a step of evaluating the output by a genetic algorithm based on the evaluation of the output light. Adjusting the amount of operation in each of the plurality of degrees of freedom so that the light is optimized.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of an embodiment of an interferometer of the present invention used in an embodiment of an interferometer adjusting method of the present invention.

FIG. 2 is an explanatory view showing an adjustment driving device in the interferometer of the embodiment together with a plane mirror.

FIG. 3 is an explanatory diagram showing a detection board in the interferometer of the embodiment.

FIG. 4 is a flowchart illustrating a flow of an adjustment method according to the embodiment.

FIG. 5 is a flowchart showing a flow of a genetic algorithm in the adjustment method of the embodiment.

FIG. 6 is a flowchart showing a flow of evaluation by a genetic algorithm in the adjustment method of the embodiment.

FIG. 7 is a flowchart showing a flow of replacement in a genetic algorithm in the adjustment method of the embodiment.

FIG. 8 is a flowchart showing a flow of a hill-climbing method in the adjustment method of the embodiment.

FIG. 9 is an explanatory diagram of a search algorithm that combines a genetic algorithm and a hill-climbing method in the adjustment method of the embodiment.

FIG. 10 is a configuration diagram showing a basic configuration of an infrared spectrophotometer (FTIR).

FIG. 11 is a configuration diagram showing a basic configuration of an interferometer.

FIG. 12 is an explanatory diagram showing a basic principle of an interferometer.

FIG. 13 is an explanatory diagram showing a degree of freedom of operation required for a plane mirror of an optical system in an interferometer.

FIG. 14 is an explanatory diagram showing a degree of freedom of operation required for a corner cube mirror of an optical system in an interferometer.

FIG. 15 is an explanatory diagram showing a unimodal search for an adjustment value.

FIG. 16 is an explanatory diagram showing a multimodal search for adjustment values.

FIG. 17 is an explanatory view illustrating an adjustment driving device having a subordinate structure.

[Explanation of symbols]

 1, S light source 2 Interferometer 3 Sample chamber 4, P detector 5 Data processing unit 6 Record display unit BS beam splitter CM Corner cube mirror DE1 to DE4 Adjustment drive element F1 to F3 Plane HM Half mirror M1, M2 Reflector O optics System PB detection board PC Personal computer PD Silicon-photodiode PM Planar mirror

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masahiro Murakawa 1-1-4 Umezono, Tsukuba, Ibaraki Pref., Ministry of Economy, Trade and Industry (METI) Inside the Electronic Technology Research Institute (72) Inventor Tetsuya Higuchi Umezono, Tsukuba, Ibaraki 1-1-4, Electronic Technology Research Institute, National Institute of Advanced Industrial Science and Technology, Ministry of Economy, Trade and Industry (72) Inventor Hirokazu Nozato 1-4-1, Umezono, Tsukuba, Ibaraki Prefecture, Electronic Technology Research Institute, National Institute of Advanced Industrial Science and Technology, Ministry of Economy, Trade and Industry In-house (72) Inventor Koji Suzuki 1-A705, Kokura, Koyuki-ku, Kawasaki-shi, Kanagawa F-term (reference) 2F064 AA15 EE01 FF00 GG12 GG16 GG22 GG70 HH00 JJ01

Claims (12)

[The claims] 1. An interferometer comprising an optical system having a plane mirror having a plurality of operating degrees of freedom dependent on each other, when adjusting an operation amount of the plane mirror at each of the plurality of degrees of operation, Detecting output light from the optical system at a predetermined position, and adjusting an operation amount at each of the plurality of degrees of freedom so that the output light is optimized by a genetic algorithm based on the evaluation of the detected output light. Characterized by the fact that
How to adjust the interferometer. 2. The method according to claim 1, wherein adjusting the amount of operation at each of the plurality of degrees of freedom includes adjusting a central portion of the plane mirror, an upper portion or a lower portion,
The method for adjusting an interferometer according to claim 1, wherein the adjustment is performed by adjusting and driving the side portions. 3. The method according to claim 1, wherein the amount of operation in each of the plurality of degrees of freedom of operation is further finely adjusted by a hill-climbing method based on the evaluation of the detected output light. How to adjust the interferometer. 4. The method according to claim 1, wherein the detection of the output light is performed at a central portion, an upper portion or a lower portion, and a side portion of a detection board disposed at a predetermined position of the interferometer. 3. The method for adjusting an interferometer according to any one of the items up to 3. 5. The method according to claim 4, wherein the detection of the output light is carried out at two points having different distances from the central part for each of the upper or lower part and the side part.
How to adjust the interferometer described. 6. An interferometer including an optical system having a plurality of plane mirrors having a plurality of degrees of freedom of operation that are dependent on each other, wherein: an output light detecting means for detecting output light from the optical system at a predetermined position; 2. An interferometer for use in carrying out the interferometer adjustment method according to claim 1, further comprising: a plane mirror adjustment drive means for adjusting and driving the plurality of operation degrees of freedom. 7. The amount of operation of each of the plurality of degrees of freedom of operation of the plane mirror adjustment driving unit is adjusted so that the output light is optimized by a genetic algorithm based on the evaluation of the output light detected by the output light detection unit. 7. The interferometer according to claim 6, further comprising an operation amount adjusting means for adjusting. 8. The plane mirror adjustment driving means has three adjustment driving elements for adjusting and driving a central part, an upper or lower part, and a side part of the plane mirror, respectively. Item 7. The interferometer according to Item 7. 9. The apparatus according to claim 6, wherein said operation amount adjusting means further finely adjusts each of the plurality of degrees of freedom of operation of said plane mirror adjustment driving means by a hill-climbing method.
The interferometer according to any one of claims 1 to 8. 10. The output light detecting means has a light receiving element at a central part, an upper or lower part, and a side part of a detection board arranged at a predetermined position of the interferometer.
The interferometer according to claim 6. 11. The output light detecting means has two light receiving elements having different distances from the light receiving element in the central part, respectively, in the upper or lower part and the side part. 10. The interferometer according to 10. 12. A step of evaluating the detected output light, and adjusting an operation amount in each of the plurality of degrees of freedom so as to optimize the output light by a genetic algorithm based on the evaluation of the output light. 2. A processing program for implementing a method for adjusting an interferometer according to claim 1, wherein the program is executed by a computer.