JP2000055734A - Spectrophotometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure a large sample using an end-on type light detector unit. SOLUTION: A condensing mirror 26 removably disposed in an end-on type detector unit 20 is removed in measuring a large sample 27. A reference light beam R passing through this unit 20 is introduced to a side-on type light detector 10 through a converging mirror 7 outside the unit 20, while a sample light beam S is sent to an end-on type light detector 24 by a reflection mirror 22 and condensing mirror 23 and transmitted through the large sample 27, resulting in scattered lights reaching the light detector 24. This has no need to avoid the reference flux R, since only the sample flux S is incident on the light detector 24, and allows a large sample to be inserted as it is.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a spectrophotometer,
In particular, the present invention relates to a double beam type spectrophotometer having two paths of a sample side light beam and a reference side light beam.

[0002]

2. Description of the Related Art FIG. 3 is a diagram showing an example of an optical path configuration of a conventionally known general double beam type visible ultraviolet spectrophotometer. In this configuration, a standard sample chamber unit 12 in which two cells, a reference side cell (cell containing a solvent) 13 and a sample side cell (cell containing a sample solution) 14, are arranged side by side. It is attached to.

Light emitted from a light source 1 is introduced into a monochromator 2, and monochromatic light having a predetermined wavelength is extracted. The monochromatic light is sent to the sector mirror 4 by the reflecting mirror 3 and is alternately distributed to the sample side and the reference side by the sector mirror 4 rotating about the axis A. The reference-side light flux R reflected by the sector mirror 4 is applied to the reference-side cell 13 via the reflecting mirror 5, is transmitted through the reference-side cell 13, is reflected and condensed by the converging mirror 7, and is reflected by the photodetector 10. It is guided to the light receiving surface.

On the other hand, the sample-side luminous flux S that has not hit the reflecting mirror surface of the sector mirror 4 is radiated to the sample-side cell 14 via the reflecting mirror 6 and transmitted through the sample-side cell 14 before being reflected / collected by the condensing mirror 8. The light is then reflected by the folded plane mirror 9 and guided to the light receiving surface of the photodetector 10. The reference beam R passing through the reference cell 13 and the sample beam S passing through the sample cell 14 are alternately introduced into the photodetector 10 in synchronization with the rotation of the sector mirror 4. By performing predetermined signal processing using the received light signal, noise, light amount fluctuation,
Alternatively, an accurate absorbance can be calculated by canceling the influence of the solvent such as light absorption. Note that a photomultiplier tube is used as the photodetector 10, and the photodetector 10 used here is called a side-on type photodetector due to its structural features.

[0005] It is desirable that this type of spectrophotometer is configured to be able to measure various types or forms of samples. In the configuration of FIG. 3, when a sample such as a solution with high turbidity or polished glass, in which transmitted light spreads as scattered light, is placed at the position of the sample-side cell 14, only a part of the transmitted light is collected. Since the light does not impinge on the optical mirror 8, the amount of light introduced into the photodetector 10 is greatly reduced, and accurate measurement cannot be performed.

In such a case, a sample chamber unit having another configuration called an end-on type photodetector unit 20 is mounted in the sample chamber installation space 11 instead of the sample chamber unit 12. FIG. 4 is a diagram showing an optical path configuration when the end-on type photodetector unit 20 is mounted on the spectrophotometer. The end-on type photodetector unit 20 includes a condenser mirror 21 for reflecting and condensing the reference-side light flux R.
A reflecting mirror 22 for reflecting the sample-side light flux S, and a condensing mirror 23 for reflecting and condensing the light flux reflected by the reflecting mirror 22;
And a photodetector 24. The photodetector 24 used here is a photomultiplier tube called an end-on photodetector or a head-on photodetector. End-on type photodetectors have a wide angle range of detectable incident light,
Since the effective light receiving surface is wide, scattered light arriving from various directions can be detected efficiently.

In the configuration in which the end-on type photodetector unit 20 is mounted, each component described on the right side of the sample chamber installation space 11 in FIG. 4, that is, used when the above-described sample chamber unit 12 is mounted. The components that were used are not used.

In the end-on type photodetector unit 20,
As shown in FIG. 4, a sample to be measured (for example, a solid sample such as polished glass) 25 is included in the sample-side light flux S immediately before the photodetector 24.
Is inserted. Since the distance between the sample 25 and the photodetector 24 is short, even if the light transmitted through the sample 25 is bent or diffused, most of the transmitted light reaches the light receiving surface of the photodetector 24. Therefore, the absorbance of the sample 25 can be calculated from the sample-side light flux S and the reference-side light flux R that alternately reach the photodetector 24 in synchronization with the rotation of the sector mirror 4. In addition,
When the sample 25 is a solution and needs to be accommodated in a cell, a cell containing a solvent is also inserted into the reference-side light flux R immediately before the photodetector 24 to measure the spectrum of only the solute in the sample solution. Becomes possible.

[0009]

However, in the end-on type photodetector unit 20, it is necessary to insert the sample 25 at a position where the sample-side light beam S and the reference-side light beam R are extremely close to each other. Since it is necessary not to cover the reference light beam R, the measurable sample 2
The size of 5 is limited to fairly small ones. For this reason, a large sample must be partly cut out to a measurable size. In addition, a large sample that cannot be cut out cannot be measured.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an object of the present invention is to provide a double beam capable of measuring a large sample using an end-on type photodetector unit. Spectrophotometer of the type.

[0011]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention divides light emitted from the same light source into two systems, a sample-side light beam and a reference-side light beam, and converts the light into a light beam on the sample-side light beam. Is a double beam type spectrophotometer in which a transmitted light or reflected light and a reference side light beam are respectively detected by a photodetector, and a first cell in which a sample side cell and a reference side cell are provided. A first optical path configuration in which the first photodetector detects the sample-side light beam and the reference-side light beam that have passed through the sample chamber unit with the sample chamber unit attached thereto, and instead of the first sample chamber unit, A second sample chamber unit including a second photodetector and a second sample chamber unit including a plurality of reflecting mirrors each of which reflects the sample-side light beam and the reference-side light beam and guides them to the second light detector. In a spectrophotometer capable of selecting an optical path configuration, the second
A reflector for the reference-side light beam of the sample chamber unit is detachably provided, and the sample-side light beam is guided to the second photodetector by removing the reflector. A third optical path configuration for leading to the vessel.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the spectrophotometer of the present invention will be described below with reference to FIG. FIG. 1 is an optical path configuration diagram of a spectrophotometer which is an example of the present invention. In this spectrophotometer, the second sample chamber unit corresponds to the end-on type photodetector unit 20. The basic configuration of the end-on type photodetector unit 20 is the same as that shown in FIG. 3, except that the condenser mirror 26 installed in the reference light beam R is detachable. . As shown in FIG. 1, when measuring a large sample 27, the condenser mirror 26 is removed.

In this case, the reference light beam R reflected by the sector mirror 4 is sent to the end-on type photodetector unit 20 via the reflecting mirror 5, but goes straight through because there is no condenser mirror 26, The light is reflected and condensed by the condenser mirror 7 and is introduced into the side-on type photodetector 10. On the other hand, the sample-side light flux S that has traveled straight without hitting the reflecting surface of the sector mirror 4 is sent into the end-on type photodetector unit 20 via the reflecting mirror 6,
After being reflected by the reflecting mirror 22, the light is reflected and condensed by the condensing mirror 23 and sent to the photodetector 24. This light beam enters a large sample 27 placed just before the photodetector 24, and the transmitted light reaches the light receiving surface of the photodetector 24.

Accordingly, the end-on type photodetector 24 outputs a light receiving signal for the sample side light beam S transmitted through the large sample 27, and the side-on type photodetector 10 outputs a light receiving signal for the reference side light beam R. Since the light receiving signals of the two are alternately obtained in synchronization with the rotation of the sector mirror 4, for example, the switch 29 for switching the connection in synchronization with the rotation of the sector mirror 4
If the light receiving signals of the two photodetectors 10 and 24 are switched and extracted, the light receiving signals can be output alternately. Of course, in addition to switching the light receiving signal by the switch 29, the outputs of the two photodetectors 10 and 24 are respectively taken into a signal processing unit (not shown), and a signal corresponding to the sample-side light flux S and the reference-side light flux R in the signal processing process. May be taken out.

In this configuration, the end-on type photodetector 24
Since only the sample-side light flux S is incident on the sample 27, the size of the sample 27 is not limited as long as it can be stored in the end-on type photodetector unit 20.

FIG. 2 is an optical path configuration diagram showing another embodiment of the spectrophotometer according to the present invention. In this example, the light reflected by the sector mirror 4 is referred to as a sample-side light flux S, and the light traveling straight without hitting the reflection surface of the sector mirror 4 is referred to as a reference-side light flux R. In this case, the position of the condenser mirror 21 is fixed, and the reflection mirror 28 is detachable.

When the reflecting mirror 28 is detached during the measurement of the large sample 27, the reference light beam R introduced into the end-on type photodetector unit 20 via the reflecting mirror 6 is applied to the unit 2
After passing through 0, the light is sent to the side-on type detector 10 via the condenser mirror 8 and the folded plane mirror 9. On the other hand, the sample side light flux S
Is reflected and condensed by the condenser mirror 21 and sent to the end-on type photodetector 24. In this case, the large sample 27 may be placed immediately before the photodetector 24 as shown in FIG. 2, or may be placed at a position 27 'immediately before the condenser mirror 21 as shown by a dotted line in FIG. .

It should be noted that the above embodiment is merely an example, and it is apparent that modifications and modifications can be made as appropriate within the spirit of the present invention.

[0019]

As described above, according to the spectrophotometer according to the present invention, since only the sample side light beam is introduced into the end-on type photodetector, the sample is inserted so as to avoid the reference side light beam. Alternatively, it is not necessary to install the apparatus, and the measurement can be performed without cutting out a large sample.

[Brief description of the drawings]

FIG. 1 is an optical path configuration diagram of a spectrophotometer according to an embodiment of the present invention.

FIG. 2 is an optical path configuration diagram of a spectrophotometer according to another embodiment of the present invention.

FIG. 3 is an optical path configuration diagram of a conventional general double beam type visible ultraviolet spectrophotometer.

FIG. 4 is an optical path configuration diagram of a conventional spectrophotometer using an end-on type photodetector.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Light source 2 ... Monochromator 4 ... Sector mirror 5, 6 ... Reflecting mirror 7, 8 ... Condensing mirror 9 ... Folded plane mirror 10 ... Side-on type photodetector (first photodetector) 11 ... Sample chamber installation space 12: sample chamber unit (first sample chamber unit) 20: end-on type photodetector unit (second sample chamber unit) 21, 23: condensing mirror 22: reflecting mirror 24: end-on type photodetector (second 26 ... detachable condenser mirror 27 ... large sample 28 ... detachable reflector

Claims (1)

[Claims] 1. A light beam emitted from the same light source is divided into two systems, a sample-side light beam and a reference-side light beam, and a sample is disposed on an optical path of the sample-side light beam. Is a double-beam type spectrophotometer for detecting a light beam with a photodetector, wherein a first sample chamber unit containing a sample cell and a reference cell is mounted, and a sample-side luminous flux passed through the sample chamber unit. And a first optical path configuration for detecting the reference light beam by the first photodetector, and instead of the first sample chamber unit,
A second sample chamber unit including a second photodetector and a second sample chamber unit including a plurality of reflecting mirrors each of which reflects the sample-side light beam and the reference-side light beam and guides them to the second light detector. In a spectrophotometer capable of selecting an optical path configuration, a reflecting mirror for a reference-side luminous flux of the second sample chamber unit is detachably provided,
By removing the reflecting mirror, the sample-side light beam is guided to the second photodetector, while the reference-side light beam forms a third optical path configuration for leading to the first photodetector. Spectrophotometer.