JPS628505Y2 - - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a photometric device.

When using a photometric device, such as a spectrophotometer, to measure the transmitted light of a sample with a high refractive index, such as a glass block or lens, such a sample refracts the light, causing the transmitted light to be focused or diverged. Therefore, the cross-sectional shape or size of the light beam on the light-receiving surface of the detector changes depending on the sample, and is therefore strongly affected by local sensitivity unevenness on the light-receiving surface, making it difficult to accurately measure transmitted light.

In view of this point, an integrating sphere is used in the photometry section and is displaced in the optical axis direction of the light beam from the sample to adjust the position of the integrating sphere with respect to the light beam. However, although this method makes it possible to equalize the size of the cross-section of the light flux near the entrance of the integrating sphere, the area of the part where the light flux hits the inner wall of the integrating sphere is Therefore, the influence of local unevenness of the paint on the inner wall of the integrating sphere is particularly large in the ultraviolet region shorter than 400 nm, making accurate measurements impossible.

This idea was proposed in consideration of this point.
It consists of a light source, a spectrometer, a sample holder, and a photodetector, and this photodetector is combined with a photoelectric conversion element in which a light diffuser is disposed closely or in close proximity to the front surface of the light-receiving surface, and this element is The present invention is characterized by comprising means for holding light from the sample so as to be freely displaceable in the optical axis direction.

Hereinafter, a detailed explanation will be given according to the illustrated embodiment.

In FIG. 1, 1 is a light source, 2 is a spectrometer, 3 is a sample holder, 4 is a sample, for example, an optical lens, 5 is a detector, 6 is a diffuser, 7 is a photoelectric conversion element,
For example, a photomultiplier tube. The diffuser 6 is disposed close to or closely in front of the light receiving surface of the photomultiplier tube 7 .

The light from the light source is separated by a spectrometer, and the monochromatic light is irradiated onto the lens of the sample. The light transmitted through the sample is irradiated onto a diffuser, and the diffused light is incident on the photomultiplier tube 7.

The feature of the present invention is that the displacement of the photoelectric conversion element equipped with a diff user is adjusted in the optical axis direction of the light transmitted through the sample, so that the cross-sectional shape of the light beam hitting the diff user can be maintained substantially the same regardless of the difference in the sample. It is in.

FIG. 2 shows an example of a mechanism for displacing the detector in the optical axis direction. Reference numeral 10 denotes a guide bench provided parallel to the optical axis L of the transmitted light of the sample 4, and has a protruding strip 11 provided on its upper surface. A carriage 12 houses the photomultiplier tube 7 and the diffuser 6, and has a groove 13 on the bottom surface into which the protrusion 11 of the guide bench 10 is fitted, so that it can slide freely along the protrusion. Convex strip 11 is "dovetail"
It is desirable that the dovetail groove 13 be a corresponding "dovetail groove".

14 is a screw for fixing the carriage at a desired position on the guide bench; 15 is an entrance window provided on the front surface of the carriage; and 16 is a cord for taking out the output electrical signal of the phototube.

According to the proposed device, first, the 100% line is adjusted by applying light to the diff user without placing the sample in the optical path (in an air blank state) (Fig. 3a). At this time, the cross-sectional shape or size d of the light beam on the surface of the diffuser 6 is recorded, for example, on the scale of a shutter provided just before the diffuser surface, and the transmitted light when a sample is placed in this cross-sectional shape or size. By adjusting the position of the photoelectric conversion element so as to match the cross-sectional shape or size on the diffuser surface of the light beam, it is possible to eliminate measurement errors due to differences in the cross-sectional shape or size of the light beam on the diffuser surface due to different samples. That is, for example, if the sample is a convex lens 4a with a short focal length, the carriage 1
2 toward the sample (Figure 3b), and conversely, if the sample is a convex lens 46 with a long focal length, the carriage is moved away from the sample (Figure 3c).
In either case, the cross-sectional shape or size of the light beam on the front surface of the differential user is made to match that of the air blank.

In the illustrated embodiment, a large-diameter end-on type photomultiplier tube is used, and this type is preferable, but a sand-on type photomultiplier tube may also be used. In addition to phototubes, photoconductive cells, solar cells, etc. may also be used.

Opalescent glass can be used as a diff user, but if a quartz plate with a ground surface on both or one side is used, the ultraviolet region shorter than 340 nm can also be covered. As shown in FIG. 4, a pipe 20 whose inner surface is vapor-deposited with aluminum, for example, and a diffuser 6 attached to the front end thereof may be placed in front of the photoelectric conversion element.

A scale indicating the position of the carriage may be provided on the top surface of the bench or the top surface of the protrusion. Furthermore, the mechanism for displacing the photoelectric conversion element together with the differential user is not limited to the illustrated example; for example, a groove may be provided on the bench side, a protrusion may be provided on the carriage, and other configurations are also possible.

Of course, the sample is not limited to a solid sample like the illustrated lens, but may also be a liquid sample.

As described above, according to the present invention, in the photometry device, the photoelectric conversion element in which the diff user is disposed immediately before is displaced in the optical axis direction with respect to the sample, so that the cross-sectional shape or size of the light flux on the diff user surface of the light transmitted through the sample can be changed. Since the intensity can be made constant regardless of the sample, the influence of local sensitivity unevenness on the light-receiving surface of the photoelectric conversion element can be minimized. In addition, the distance between the sample and the detector can be changed, so in the case of translucent samples such as suspensions, the detector can be brought closer to the sample to measure transmitted light with high sensitivity, and conversely, the transmitted light can be measured with high sensitivity. By moving the detector away from the generated sample, the effect of fluorescence can be virtually completely eliminated. It should be noted that the present invention is of course applicable not only to spectrophotometers but also to other photometric devices.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the principle of construction of the present invention, Fig. 2 is a perspective view showing an example of a specific arrangement for displacing the detector in the optical axis direction, Figs. It is a figure showing a modification. 4...Sample, 6...Difuser, 7...Photoelectric conversion element, 10...Guide bench, 12...Carriage, L...Optical axis.

Claims (1)

[Scope of utility model registration request] It consists of a light source, a spectrometer, a sample holder, and a photodetector, and this photodetector is combined with a photoelectric conversion element in which a light diffuser is disposed closely or in close proximity to the front surface of the light-receiving surface, and this element is 1. A photometric device comprising means for holding light from a sample so as to be freely displaceable in the optical axis direction.