JP4126477B2 - Spectrophotometer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a reflection-type light measurement apparatus, and more particularly to a spectrophotometer that performs spectroscopic analysis by moving a reflecting mirror to a fixed position using a light source.
[0002]
[Prior art]
An analyzer that performs qualitative and quantitative analysis by irradiating the sample with light and spectroscopically measuring the spectrum of the light, and qualitative and quantitative analysis. Ultraviolet and visible spectrophotometer, near infrared or infrared spectrophotometer, fluorophotometric analyzer and so on. When light passes through a material, the energy of the light causes a change in the electronic state of the material and some of that energy is lost. The energy lost by light corresponds to the electronic state of the material. Therefore, in order to investigate what kind of light caused the change, the sample was irradiated while changing the wavelength of the light, and the intensity of the light before entering the sample and after leaving the sample was compared. The absorption spectrum is obtained by expressing the relationship curve with the wavelength of the irradiated light, which is expressed in percent transmission. Since this absorption spectrum gives information on the electronic state of the molecule, it is an important clue for knowing the structure of the compound.
[0003]
FIG. 4 shows a block system diagram of a conventional reflective spectrophotometer. The light from the light source 15 is converged by the concave reflecting mirror of the optical system 16, passes through the slit to be parallel light by the concave reflecting mirror, is split by the diffraction grating of the spectroscope 17, and passes through the concave mirror of the optical system 18. Then, it is input to the optical fiber end face of the input fiber 20. The light input to the optical fiber 1 is emitted from the end face of the optical fiber 1 of the sampler unit 19. At the time of photometry, if the sample is gas or liquid, the sample is put in a sample cell (not shown), and if the sample is solid, the optical fiber is processed into a film or paste or by the ATR method. 1 is set on the end face. The light applied to the sample is transmitted and reflected through the sample, returns to the end face of the optical fiber 1 again, and is guided to the other end via the output fiber 21. The light from the end face of the output fiber 21 is converged by the concave reflecting mirror of the optical system 22 and detected by the detector 23. Further, when measuring the reference light in the absence of the sample, the reference mirror 13 of the total reflection flat mirror is set on the end face of the optical fiber 1, and the light reflected by the reference mirror 13 passes through the output fiber 21 to the other end. Led to. The light from the end face of the output fiber 21 is converged by the concave reflecting mirror of the optical system 22 and detected by the detector 23. The analog signal is amplified, converted into a digital signal by an A / D converter, and arithmetically processed by a digital processing unit. This is performed for each wavelength to obtain an absorption spectrum.
[0004]
[Problems to be solved by the invention]
The conventional spectrophotometer is configured as described above. When measuring the reference light in the absence of the sample, the reference mirror 13 of the total reflection plane mirror is set on the end face of the optical fiber 1, and the reference mirror 13 The reflected light is guided to the other end via the output fiber 21, but when the reference mirror 13 is set on the end face of the optical fiber 1, there is no position reproducibility, so the reproducibility of the measurement result cannot be obtained. There was a problem. Further, even if the reference mirror 13 is attached to the tip of the arm and moved manually to the contact surface with the other end as a fulcrum, there is a problem in that there is no reproducibility of the position of the reference mirror 13 if the pressure applied to the contact surface changes. .
[0005]
The present invention has been made in view of such circumstances, and when measuring reference light in the absence of a sample, the reference mirror 13 of the total reflection flat mirror is positioned on the end face of the optical fiber 1 with good reproducibility. It aims at providing the spectrophotometer provided with the mechanism which can do.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the spectrophotometer of the present invention puts light emitted from a light source into a spectroscope through an optical system, and splits the dispersed light into a light entrance / exit of a sample measuring chamber through the optical system. feed to the end face, the sample, or, by setting the reference mirror on the end face, it captures the reflected light at the end face, in a spectrophotometer for analyzing enter the detector through an optical system, the previous end of the arm to a reference mirror provided inside the mirror holder mounted via a spring member, about the other end of the arm attached to the arm, and attracting means for rotating the arm, the rotation of said arm A block that stops at a fixed position, and the end face of the light entrance of the sample measurement chamber is provided in parallel to the surface on which the arm rotates, and the arm is rotated by the attraction means during reference light measurement The mirror holder is brought into contact with the edge of the end face of the light entrance of the sample measuring chamber, and the arm is pulled to the block while changing the angle of the mirror holder with respect to the end face of the light entrance of the sample measuring chamber. , A mirror moving mechanism in which the mirror holder is pressed against the end face with a constant force by the spring material, and a reference mirror inside the mirror holder is set in parallel at a constant distance from the end face of the light entrance of the sample measuring chamber Is provided.
[0007]
The spectrophotometer of the present invention is configured as described above, and the reference mirror moving mechanism includes a rotating arm, a contact surface that stops the rotating arm at a fixed position, and the arm is rotated and pushed against the contact surface with a constant force. It consists of a pulling spring for contact, a mirror holder attached to the tip of the arm via a leaf spring, and a reference mirror mounted in the mirror holder, and the arm with the reference mirror at the tip is rotated to the contact surface by the pulling spring The reference mirror is moved to a fixed position on the light entrance / exit end face, and at the same time, the mirror holder is pressed against the light entrance / exit end face with a constant force by a leaf spring provided at the tip of the arm. The reference mirror is set at a certain distance from the entrance / exit end face. For this reason, the position of the reproducible reference mirror can be maintained, and a reliable measurement can be performed. When the measurement of the reference light is completed, the arm can be returned to the original position and stopped with a stopper or the like.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the spectrophotometer of the present invention will be described with reference to FIG. FIG. 1 is a view showing a mirror moving mechanism of the spectrophotometer of the present invention. This mirror moving mechanism is attached to the base 3 via the optical holder 1 for measurement, the rotary shaft 5 attached to the base 3 via the bearing 6, and the rotary shaft 5. Arm 4, U-shaped plate spring 11 attached to the tip of arm 4, mirror holder 12 attached via U-shaped plate spring 11, and measurement light provided in mirror holder 12 are reflected. A reference mirror 13 for measuring the reference light, and a pulling spring hung on the spring support pin 9a and the spring support pin 9 of the arm 4 in order to draw and move the reference mirror 13 onto the end face of the optical fiber 1 when measuring the reference light. 8, the abutment block 7 provided so that the arm 4 rotates and the reference mirror 13 is in a predetermined position, and the mirror holder 12 is an optical fiber The notch 14 of the mirror holder 12 provided so as not to damage the end face when moving to the end face, and a pluggable stopper for returning the reference mirror 13 to the original position and stopping after completion of the reference light measurement. 10.
[0009]
Bearings 6 are used above and below the base 3 to rotate the rotating shaft 5 with high accuracy, and coil springs are used as the tension springs 8 to press the arm 4 against the contact surface of the contact block 7 with a constant pressure. ing. As shown in FIG. 2, the U-shaped plate spring 11 is (a) U-shaped in the rotation direction of the arm 4, and (b) the mirror holder 12 slides into the end face of the optical fiber 1. Then, (c) the mirror holder 12 is pressed against the end face of the optical fiber 1 with a predetermined pressure. Therefore, the distance from the end face of the optical fiber 1 to the reference mirror 13 is always a predetermined interval. As shown in FIG. 1, a notch 14 is provided in the mirror holder 12 so that the end face of the optical fiber 1 is not damaged when the mirror holder 12 moves to the end face of the optical fiber 1. When the reference light measurement is completed, the arm 4 is manually returned to the original position, and the removable stopper 10 is inserted into the base 3 and stopped. Although this operation is performed manually, it may be performed automatically by a motor or an electromagnet.
[0010]
Next, the operation using the spectrophotometer of the present invention will be described with reference to FIG. This photometer is different from the conventional photometer in the setting method of the reference mirror 13 of the sampler unit 19, and the others are the same. First, the photometer is turned on, and the process starts when a predetermined preparation is made and the apparatus is stabilized. Next, the prepared measurement sample is set on the end face of the optical fiber 1 of the sampler unit 19. The light from the light source 1 is converged by the concave reflecting mirror of the optical system 16, passes through the slit to be parallel light by the concave reflecting mirror, is split by the diffraction grating of the spectroscope 17, and is concaved by the optical system 18. Through the optical fiber end face of the input fiber 20. The light input to the optical fiber 1 is emitted from the end face of the optical fiber 1 of the sampler unit 19. The light applied to the sample is transmitted and reflected through the sample, returns to the end face of the optical fiber 1 again, and is guided to the other end via the output fiber 21. The light from the end face of the output fiber 21 is converged by the concave reflecting mirror of the optical system 22 and detected by the detector 23. Next, in order to measure the reference light in the absence of the sample, the measurement sample of the sampler unit 19 is removed, the removable stopper 10 of the mirror moving mechanism shown in FIG. The mirror holder 12 is pressed against the end face of the optical fiber 1 by the U-shaped plate spring 11 and is separated from the end face by a predetermined distance. Is set. The light reflected by the reference mirror 13 is guided to the other end via the output fiber 21. The light from the end face of the output fiber 21 is converged by the concave reflecting mirror of the optical system 22 and detected by the detector 23. The analog signal is amplified, converted into a digital signal by an A / D converter, and arithmetically processed by a digital processing unit. This is performed for each wavelength to obtain an absorption spectrum.
[0011]
In the above embodiment, the tension spring 8 is used as means for applying the arm 4 to the contact block 7 with a constant force. However, another method using an electromagnet or the like may be used. Further, although the U-shaped plate spring 11 is used for the mirror holder 12 as means for lifting the reference mirror 13 from the end face by a certain distance, other spring mechanisms can be used. Moreover, although the upper and lower bearings 6 have the swing of the rotating shaft 5, the rotating mechanism is not limited to the bearings 6 and may be any other accurate rotating mechanism. The same effect can be obtained even if the end face of the light inlet / outlet of the sampler portion 19 is not the fiber type of the optical fiber 1.
[0012]
【The invention's effect】
The spectrophotometer of the present invention is configured as described above, and when measuring the reference light without a sample, even if a reference mirror is taken in and out of the entrance / exit end face of the measurement light in the sample measurement chamber, The reference mirror is attracted by a spring with a constant force and held at a predetermined position on the contact surface. Furthermore, the distance between the reference mirror and the input / output end face of the measurement light is constant with a U-shaped plate spring attached to the reference mirror holder. become. Therefore, the position reproducibility is excellent and the reliability of the measurement result is high. Furthermore, when the reference mirror is set, it is inserted smoothly and the notch is provided in the holder, so that the input / output end face of the measurement light is not damaged. Further, after the measurement is completed, the reference mirror can be returned to the original position, and the rotation can be stopped with a stopper.
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment of a mirror moving mechanism of a spectrophotometer according to the present invention.
FIG. 2 is a diagram showing the setting of a reference mirror of the spectrophotometer of the present invention.
FIG. 3 is a view showing an embodiment of the spectrophotometer of the present invention.
FIG. 4 is a view showing a conventional spectrophotometer.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Optical fiber 2 ... Fiber holder 3 ... Base 4 ... Arm 5 ... Rotating shaft 6 ... Bearing 7 ... Contact block 8 ... Pulling spring 9 ... Spring support pin 9a ... Spring support pin 10 ... Removable stopper 11 ... U-shaped plate Spring 12 ... Mirror holder 13 ... Reference mirror 14 ... Notch 15 ... Light source 16 ... Optical system 17 ... Spectroscope 18 ... Optical system 19 ... Sampler unit 20 ... Input fiber 21 ... Output fiber 22 ... Optical system 23 ... Detector

Claims (2)

The light emitted from the light source enters the spectroscope via the optical system, the split light is sent to the end face of the light entrance / exit of the sample measurement chamber via the optical system, and the sample or reference mirror is set on the end face to, capture the reflected light at the end face, in a spectrophotometer for analyzing enter the detector through an optical system, provided in the interior of the mirror holder which is attached via a spring member in the previous end of the arm A reference mirror attached to the arm, an attracting means for rotating the arm around the other end of the arm, and a block for stopping the rotation of the arm at a fixed position. An end face of the light entrance is provided in parallel to the surface on which the arm rotates, and the arm is rotated by the attracting means during reference light measurement, and the edge of the end face of the light entrance of the sample measurement chamber is aligned with the edge -The holder is brought into contact, and the arm is pulled to the block while changing the angle of the mirror holder with respect to the end face of the light entrance of the sample measuring chamber, and the mirror holder is pushed against the end face by a constant force by the spring material. The spectrophotometer further includes a mirror moving mechanism in which the reference mirror inside the mirror holder is set in parallel at a constant distance from the end face of the light entrance of the sample measuring chamber. 2. The spectrophotometer according to claim 1, wherein the mirror holder has a notch in a portion that comes into contact with an end face of the light entrance of the sample measurement chamber.

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