JPS6125093B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a diffuse reflection measuring device for a spectrophotometer, and particularly to a spectrophotometer having an optical system that contributes to an increase in incident energy and is suitable for use in an infrared spectrophotometer. This invention relates to a diffuse reflection measuring device.

Conventionally, there have been few examples of measuring diffuse reflection in infrared spectroscopy, and it has been considered extremely difficult. That is,
Conventionally, there was no diffuse reflectance measuring device commercially available, so a commercially available powder reflectance measuring device 10 was attached to the sample light 8 side of the sample chamber 2 of the infrared spectrophotometer main body 1 to measure the diffusion, as shown in Fig. 1. I was measuring reflections.
In the figure, 3 is the light source of the infrared spectrophotometer main body 1;
4 is a plane mirror for reflecting the light emitted from the main body light source 3; 5 is a concave mirror for focusing the light reflected by the plane mirror 4 as reference light 6 or sample light 8; 7 is the above-mentioned A photometric diaphragm disposed in the optical path of the control light 6; 9 a shutter for shielding the sample light 8 as necessary; 11 a light source for the partial reflection measurement device 10; 12 the powder reflection A condenser mirror 14 reflects and condenses the light emitted from the measurement light source 11 and irradiates it onto the sample 13, and the light is diffusely reflected by the sample 13 and passes through the hole 12a of the condenser mirror 12. a plane mirror for reflecting light; 15 is a concave mirror for reflecting the light reflected by the plane mirror 14;
A plane mirror 16 reflects the light reflected by the concave mirror 15 again and enters the infrared spectrophotometer main body 2 as sample reflected light 17 instead of the normal sample light 8.

In this way, conventionally, the shutter 9 on the sample light 8 side of the infrared spectrophotometer main body 1 is closed to block the incidence from the main body light source 3, and the powder reflection measuring device 1
The light from the 0 light source 11 is made to enter the infrared spectrophotometer main body 1 as sample reflected light 17.
Therefore, the light beam from the light source 11 for the powder reflection measuring device is incident on the condenser mirror 12 with a spread of θ ₁ degree, and the image of the light source 11 is condensed onto the surface of the sample 13. A hole 12a is opened in the center of the condenser mirror 12, and the diffuse reflection component of the sample 13 is taken out from this hole 12a, and is reflected as sample reflected light 17 into the infrared spectrophotometer main body 1.
and is spectroscopically measured.

In general, the energy of diffusely reflected light is very weak.
Normally, the energy is reduced to 1/100 to 1,000 of the energy of the light source 11. Therefore, such conventional measuring methods have the following drawbacks.

1. The incident angle θ ₁ from the light source 11 is usually small, 40 to 50 degrees, and the utilization rate of light source energy is low.

2. When performing comparative measurements with a standard measurement plate, it is necessary to remove the standard diffusion plate for each comparison measurement, which is extremely complicated.

3. It is difficult to measure both the specular reflection component and the diffuse reflection component.

The present invention has been made to solve the above-mentioned conventional drawbacks, and in particular, it is a spectrophotometer that can effectively utilize light source energy and that can easily perform comparative measurements with a comparison object such as a standard diffuser plate. The purpose of the present invention is to provide a diffuse reflection measuring device.

The present invention provides a diffuse reflectance measuring device for a spectrophotometer that irradiates the sample with light emitted from a light source and measures the diffuse reflection component from the reflected light. and at least one pair of concave mirrors substantially facing each other are arranged so as to sandwich the light source and the sample stage;
The above object is achieved by irradiating the sample or comparison object with the light that has been reflected by the pair of concave mirrors.

Moreover, by making the concave mirror a parabolic mirror,
This increases the efficiency of reflected light and reduces light spots.

Embodiments of the present invention will be described in detail below with reference to the drawings. In this embodiment, as shown in FIG. 2, in a diffuse reflection measuring device 20, 11 pairs of parabolic mirrors 21 and 22, which are first and second concave mirrors facing each other, are used as a light source for the diffuse reflection measuring device. 19 and sample 13 are arranged so as to sandwich them at their respective focal positions, sample 1
3 is disposed on one side of the rotating sample stage 24 having the rotating shaft 23, and the rotating sample stage 24
A standard diffuser plate 25 is attached to the surface opposite to the sample 13, and a circular aperture 16 can be inserted between the light source 19 and the sample 13 if necessary. Different from measuring equipment. The other points are the same as those of the conventional powder reflection measuring device, so the explanation will be omitted.

The action will be explained below. Light from the light source 19 for the diffuse reflection measurement device first enters the parabolic mirror 21 at an angle of spread of θ ₂ °. This θ ₂ ° is approximately 160° ~
180°, the utilization rate of the light source energy from the light source 19 is increased, and the energy of the diffusely reflected light is also increased by about 5 to 10 times compared to that of the conventional method. The light reflected by the parabolic mirror 21 and turned into parallel rays is reflected by the other parabolic mirror 22 and focused onto the sample 13 placed at its focal point. The sample 13
The reflected light diffusely reflected by the parabolic mirror 22 is extracted from a hole 22a provided at the center of the parabolic mirror 22 as a reflected light extraction hole, as in the conventional case. The sample reflected light taken out from the hole 22a of the parabolic mirror 22 passes through a plane mirror 14, a concave mirror 15, and a plane mirror 16, as in the conventional case, and enters a spectrophotometer (not shown) of the infrared spectrophotometer main body 1 as sample reflected light 17. and a measurement is made that is compared with the reference light 6.

In this embodiment, the sample 13 is mounted on a rotating sample stage 2 that can rotate around a rotating shaft 23 as shown by arrow A.
By tilting the rotating sample stage 24, it is possible to extract and measure not only the diffusely reflected light from the sample 13 but also the specularly reflected light. Also, the sample 13 is rotated around the rotating shaft 23.
Since the structure is such that the sample 13 and the standard diffuser plate 25 are attached back to back, by rotating the rotating sample stage 24 by 180 degrees, the sample 13 and the standard diffuser plate 25 can be attached back to back.
can be easily switched for the optical path. Therefore, comparative measurements between the standard diffuser plate 25 and the sample 13 are extremely easy. Furthermore, in this embodiment, a circular diaphragm 26 is inserted into the parallel beam section as required. Therefore, as shown in FIG. 3, the angle of incidence of the light on the sample 13 can be changed, and the angular dependence of the diffused light on the angle of incidence can also be known. This angular dependence of diffused light on the incident angle is extremely useful, particularly in the measurement of heat collecting elements used in research on solar heat utilization. In other words, it is not possible to obtain such an angular distribution using an integrating sphere as in the past, but according to the method of the present invention, it is possible to easily obtain the angular distribution from the difference in the measured values of circular apertures with different diameters. It is possible.

Furthermore, in the conventional device shown in Fig. 1,
Since the sample 13 is fixedly placed close to the condensing mirror 12, it is not easy to attach and detach the sample. However, in this embodiment, by rotating the rotary sample stage 24 and directing the sample 13 to the opposite side of the parabolic mirror 22, it becomes extremely easy to attach and detach the sample 13.

In the above embodiment, if direct light from the light source 19 becomes a problem, the shielding plate 27 is
1 and the sample 13.

A second embodiment of the invention is shown in FIG. The diffuse reflection measurement device 29 of this embodiment is configured to actively utilize the direct light emitted from the light source 19 for the diffuse reflection measurement device as a reference light source. A plane mirror 30 having a hole 30a in the center is disposed in the middle, and the parabolic mirrors 21 and 22 are disposed with their optical axes tilted at 90 degrees so that they substantially face each other through the plane mirror 30. The point where the light reflected by the sample 13 and passed through the hole 22a of the parabolic mirror 22 enters the plane mirror 16 via the reflection mirror 14, the concave mirror 15, and the reflection mirror 31, and passes through the hole 30a of the plane mirror 30. This embodiment differs from the first embodiment in that the light is made to enter the infrared spectrophotometer main body 1 as reference light 6 via a plane mirror 32, a concave mirror 33, and a plane mirror 34. In the figure, 35 is a shutter for shielding the control light 6 from the main body light source, 36 is for preventing direct light emitted from the light source 19 for the diffuse reflection measuring device from being irradiated onto the sample 13, disposed between the light source 19 and the plane mirror 30,
This is a shielding plate having a hole 36a in the center.

In this embodiment, since the light source 19 for the diffuse reflection measuring device is also used as the reference light 6 in the infrared spectrophotometer main body 1, The light source and the sample reflected light are the same, improving measurement accuracy. In addition, it is easy to exchange samples.

In each of the above embodiments, a parabolic mirror is used as the concave mirror, but the type of concave mirror is not limited to this, and other concave mirrors such as a spherical mirror can also be used.

Further, in all of the above embodiments, the diffuse reflection device is separate from the main body of the infrared spectrophotometer, but it is of course possible to integrate the two.
Furthermore, in the example shown in FIG.
3 can of course be placed on a rotatable sample stage together with a standard diffuser plate, as in the embodiment shown in FIG.

In measurements using a spectrophotometer, as is well known, comparative measurements are often made between two samples, a standard flat mirror for specular reflection, or a scattering plate (ground glass surface with Al deposited on it). It will be done. Therefore, in place of the standard diffuser plate described above, other samples, specular reflection standard mirrors, scatter plates, and other comparison objects may be attached.

As explained above, the present invention includes disposing a sample together with a standard diffuser plate on a rotating sample stage, and disposing at least one pair of concave mirrors that substantially face each other so as to sandwich the light source and the rotating sample stage, Since the light reflected by the pair of concave mirrors is irradiated onto the sample or comparison object, the utilization rate of light source energy from the light source is increased, and accurate measurements are not only possible, but also standard diffusion It has the excellent effect of making it easy to perform comparative measurements with the plate.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a state of conventional infrared spectroscopy diffuse reflection measurement, and FIG. 2 is a sectional view showing a state in which a first embodiment of the diffuse reflection measurement device according to the present invention is installed in an infrared spectrophotometer. FIG. 3 is a cross-sectional view showing a state in which the angular dependence of the diffuse reflection component is being measured in the first embodiment, and FIG. FIG. 7 is a sectional view showing a state in which the second embodiment is installed in an infrared spectrophotometer. 1... Infrared spectrophotometer body, 2... Sample chamber, 6
...Control light, 13...Sample, 14,16,30,
32...Plane mirror, 15, 33...Concave mirror, 17...
...Sample reflected light, 19...Light source for diffuse reflection measurement device, 20, 29...Diffuse reflection measurement device, 21, 2
2...parabolic mirror.

Claims (1)

[Scope of Claims] 1. In a spectrophotometer diffuse reflection measurement device that irradiates a sample with light emitted from a light source and measures a diffuse reflection component from the reflected light, the light from the light source at the focal position a first concave mirror that reflects light, a second concave mirror that is arranged substantially opposite to the first concave mirror and that collects the light from the first concave mirror, and a substantially focal position of the second concave mirror; a rotatable sample stage provided at the center of the second concave mirror, and a rotatable sample stage on which a sample and a comparison object are arranged on two surfaces;
A spectrophotometer diffuse reflection measuring device, characterized in that a reflected light extraction hole is provided for guiding reflected light from a sample or a comparative object placed on the sample stage to a spectrophotometer. 2. The spectrophotometer diffuse reflection measuring device according to claim 1, wherein the concave mirror is a parabolic mirror.