JPS60117132A - Position adjustor for sample - Google Patents

Abstract

PURPOSE:To perform adjustment of the position of a sample quickly at a high accuracy by memorizing and computing the intensity of diffusively reflected infrared rays moving the sample to automatically set the sample at the position of optimum intensity. CONSTITUTION:A sample 30 is placed on a sample lift mechanism 33 as a part of a driving means, adjusted to a sufficiently low position below the focus of a concave mirror of a diffusive reflection device 29 and then, infrared rays 28 are made incident thereupon. Infrared rays diffusively reflected on the surface of a sample 30 are detected with a detector 31 and the detection signal is converted into a digital numeral with an A/D converter 34 to be memorized into a memory circuit 35. Then, a motor 32 is controlled with a control circuit 37 to move the sample 30 slightly upward and memorization is done likewise. The relative position of the sample 30 thus memorized and the sample position at which the intensity of the detection signal peaks are determined with a computation circuit 36.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for adjusting the vertical position of a sample in a diffuse reflection device used for infrared spectroscopy or the like.

[Overview of conventional technology]

Infrared spectroscopy is a method of irradiating a sample with infrared rays and measuring absorption caused by vibrations that cause changes in the dipole moment of molecular vibrations. Generally, compounds have their own unique vibrational spectra in the infrared region, and qualitative analysis can be performed by measuring the infrared absorption wavelength, and quantitative analysis can be performed by measuring the intensity of absorption at t. .

FIG. 1 shows a block diagram of a typical Fourier transform type infrared spectrometer used in infrared spectroscopy. Infrared light 2 emitted from a light source 1 is restricted in area and solid angle by an entrance aperture 8, is reflected by a concave mirror 4, and enters a parallel ray into a Michaelson interferometer 5.

Michelson interference side 5 is a semi-transparent mirror beam splitter 6
It consists of a fixed mirror 7 and a movable mirror 8. Half of the incident light beam is reflected by the beam splitter 6 and goes towards the fixed mirror 7, and the other half goes to the movable mirror 8 and is reflected, and is combined again to form parallel light beams.

The light passes through a diffuse reflection device 9 loaded with a sample, is condensed by a concave mirror 10, passes through an exit diaphragm Jll, and is focused on a detector 12.

At this time, the beam splitter 6 and the fixed mirror 7. Movable mirror 8
When there is a difference in distance between -, an optical path difference occurs between the light wave reflected by the fixed mirror 7 and the light wave reflected by the movable mirror 8, so that the combined waves cancel each other out and strengthen each other. The output from detector 12 is therefore a function of the optical path difference.

When the output from the detector 12 is subjected to 7-lier transformation, the energy distribution of infrared light for each wave number can be obtained.

Therefore, the output of the detector 12 is amplified by the amplifier 18,
It is converted into a digital value by an analog-to-digital converter 14, and further subjected to 7-lier transform by a high-speed 7-lier transform analyzer (FFT analyzer) 15. The results obtained by the fast Fourier transform analyzer 15 are output to the output device 16 either directly or after being computed by the arithmetic circuit 17 . Fast Fourier Transform Analyzer 15
．． Arithmetic circuit +7. The output device 16 is controlled by a control circuit 18, and the control circuit 18 receives commands from an input device 19. Further, a driving means 20 for driving the movable mirror 8
is controlled by the control circuit 18.

FIG. 2 shows a side view of the diffuse reflection device used in the above configuration. Here, the incident infrared light 21 is transmitted to the plane mirror 2.
, 2.28, reflected by the concave mirror 24, and the sample 25
Light is focused onto the surface. The infrared light diffusely reflected by the sample 25 is reflected and condensed by a concave mirror 26, reflected by plane mirrors 27 and 28, and sent to the detector 12.

When loading the sample 25 in the diffuse reflection device as described above, it is necessary to adjust the height of the sample 25 so that the infrared light reflected by the concave mirror 24 is focused on the surface of the sample 26.

[Disadvantages of conventional technology]

As mentioned above, in the conventional device, when adjusting the height associated with sample loading, the position (height) at which the infrared light reflected by the concave mirror 24 is focused is determined in advance, and all the samples 25 to be subjected to measurement are adjusted. It was adjusted to that height and measured. For this reason, processing of the sample 25 and processing of the pedestal installed below the sample 25 for height adjustment required high precision, resulting in problems such as a long time required for sample preparation.

[Purpose of the invention]

The present invention provides a diffuse reflection device used for infrared spectroscopy, etc.
This was done in view of the problems with the conventional device,
The object of the present invention is to provide a position adjustment device that can accurately perform sample position adjustment in a short time, which previously required a long time.

[Structure of the invention]

Therefore, the present invention provides an infrared spectrophotometer that irradiates a sample with infrared rays and measures the intensity of the diffusely reflected infrared rays, which includes: a drive means for moving the sample; a detector that measures the intensity of the diffusely reflected infrared rays from the sample; a memory circuit that simultaneously stores the infrared intensity and position information of the sample; an arithmetic circuit that compares the infrared infrared intensities from the memory circuit and selects position information corresponding to the optimum intensity; The gist of the present invention is a position adjustment device for an infrared spectrophotometer, which is characterized by comprising a control circuit that controls a driving means so that the position of the infrared spectrophotometer is adjusted.

〔Effect of the invention〕

In other words, the present invention is a position adjustment device that can store and calculate the intensity of diffusely reflected infrared rays while driving the sample in a direction perpendicular to the observation surface, and can automatically maintain the drive settings for the sample at a position with the optimum intensity. As a result, it is no longer necessary to require much precision in processing the sample or mount, which was previously done to fix the sample surface at a specific position, so sample preparation can be completed in a short time.

〔Example〕

FIG. 8 is a block diagram showing a sample position adjustment device near the diffuse reflection device according to an embodiment of the present invention. Here 2
Infrared light 8 is emitted from a light source (not shown), which is diffusely reflected on the surface of a sample 80 while passing through a diffuse reflection device 29, and then reaches the detector 31.

The sample 80 is placed on a sample lifting mechanism 83 driven by a motor 32 serving as a driving means.

It is configured such that its position can be varied slightly in the vertical direction by rotation of the motor 82.

The detection signal from the detector 31 is converted into a digital value by an analog-to-digital converter 34 and stored in a storage circuit 35. The numerical value stored in this memory circuit 85 is stored in the arithmetic circuit 8
6, and the signal is sent to the control circuit 37 according to the result. In response to this signal, the control circuit 87 controls the motor 3.
Controls the rotation of 2.

The sample 80 is placed on the sample lifting mechanism 38, which is part of the driving means, and the focal point of the concave mirror 24 of the diffuse reflection device 29 is also adjusted to a sufficiently low (or high) position. When the infrared light 28 is incident on the diffuse reflection device 29 in this state, the infrared light 28
reaches the detector 81 after being diffusely reflected on the surface of the sample 80. At this time, the upper and lower positions of the sample 80 are completely aligned with the infrared light 28
If the infrared light 28 is deviated from the optical path of the detector 81, the infrared light 28 will not reach the detector 81, but there will be no problem.

The detection signal from the detector 31 is converted into a digital value by an analog-to-digital converter 84 and stored in a storage circuit 85. In this case, it is stored together with data that allows the sample position to be distinguished. For example, in the case of the first measurement, the value 1 is also stored.

Next, the control circuit 87. Motor 82 that is part of the drive means
control to move the sample 30 slightly upward (or downward). In this state, as described above, the infrared light 28 is incident, detected by the detection unit 5sl, and converted into a digital value by the analog-to-digital converter 84, and then sent to the memory circuit 35 along with a symbol 2, for example, 2, indicating the relative position of the sample 30. to be memorized.

As above, move sample 8o slightly upward (or downward).
While moving the detector 81, the detection signal of the detector 81 is stored in the storage circuit 35 until the focal point of the concave mirror 24 shown in FIG.

As described above, from the relative position of the sample 3° stored in the storage circuit 35 and the detected signal intensity at that position, the arithmetic circuit 86 determines the sample position where the detected signal intensity is highest. As a result.

A signal is sent from the arithmetic circuit 86 to the control circuit 87 so that the sample 8o is moved to the position of the sample 80 where the detection signal intensity is highest. After that, the control circuit 87 further rotates the motor 82 to move the sample lifting mechanism 88 up and down, and
Set the 0 position.

ryr In the above embodiment, the optimum position calculation method is to measure and store the infrared intensity and position at regular intervals in advance, and then compare them at the end.

The calculation may be performed using various optimization methods such as Newton's method or slope method using infrared intensity and intensity difference.

It is also desirable that the circuits, detectors, analog-to-digital converters, etc. shown in FIG. 3 be used in common with the circuits and devices shown in FIG. 1.

[Brief explanation of the drawing]

Fig. m1 is a block diagram of a conventional infrared spectrophotometer of the Nurier transform type, Fig. 2 is an optical path diagram of a diffuse reflection device, and Fig. 8 is a block diagram showing an embodiment of the present invention. 82...Motor as part of the drive means, 88...
Sample lifting/lowering mechanism as part of driving means, 31...detector, 85...memory circuit, 36...arithmetic circuit, 37.
...Control circuit. 25 Figure 2 Figure '3'

Claims (1)

[Scope of Claims] An infrared spectrophotometer that irradiates a sample with infrared rays and measures the intensity of the diffusely reflected infrared rays, comprising: a drive means for moving the sample; a detector that measures the intensity of the diffusely reflected infrared rays from the sample; a memory circuit that simultaneously stores the infrared intensity and sample position information; Equipped with an arithmetic circuit that compares infrared infrared intensities from the memory circuit and selects position information that corresponds to the optimum intensity, and a control circuit that controls the driving means so that the sample is at the optimum position determined by the arithmetic circuit. A sample position adjustment device characterized by: