SU851209A1 - Device for measuring translucent material spectral reflection factor indicatrices - Google Patents

Description

(54) DEVICE-FOR DETERMINATION INDICATRIS

SPECTRAL REFLECTION RATIO

SEMI-TRANSPARENT MATERIALS

I

The invention relates to thermophysical measurements and can be used in the emission of the optical properties of translucent materials and their indicatrix scattering at high temperatures.

A device for determining the indicatrix of reflection of materials is known, comprising a radiation source, a sample, a radiation receiver and a modulator 1.

Closest to the present invention is a device for determining the indicatrices of the spectral reflectance of translucent materials, comprising an optical system, a standard, a radiation source, a water-cooled screen with a heater located in it, and a modulator. The design of the known device makes it possible to determine the indicatrices of the spectral reflectance of diffusely scattering translucent materials in a wide temperature range with an overview of the sample surface at an angle of ± 90 ° 2.

The disadvantages of this device are the low scanning speed of the wavelength spectrum and the instability of the light flux from the radiation source.

The purpose of the invention is to stabilize the luminous flux, increase the speed of scanning the wavelength spectrum and increase the measurement accuracy.

The goal set is achieved by the fact that

in the device for determining the indicatrix of the spectral reflectance of translucent materials, including the optical system, the radiation source, the water-cooled screen located in

10 it is a heater and a modulator, the latter is made in the form of a glass with holes in the wall with the possibility of rotation around the radiation source, two diaphragms are fixedly fixed inside the modulator, which serve to limit the luminous flux

15 to the mirror of the optical system, and the light guide with the sensor of the reference signal, with the centers of the modulator holes, the radiation source, the diaphragm and the light guide with the sensor of the reference signal located on the same optical axis.

20

Claims (2)

In this case, the modulator is placed in a protective screen, in which holes are made, which are located on the optical axis. FIG. 1 shows schematically the proposed device, a general view; in fig. 2 shows section A-A in FIG. 1. The device contains a source of I radiation, aperture 2, mirrors 3 and 4, lens 5, mirror 6, sample 7, heater 8, lens 9, window 10, monochromator slot 11, modulator 12, light guide 13, reference signal sensor 14, protective screen 15 with a hole. The device operates as follows: a radiation source 1 — an incandescent lamp — is located in a vacuum chamber (not shown). From the incandescent lamp, the light flux modulated by the modulator 12 through the diaphragms 2 and the apertures of the protective screen 15 hits the mirror 3 and the light guide 13. Then a part of the light flux with the help of mirrors 3, 4 and 6 and the lens 5 hits the sample 7, which is fixed to the heater 8, and further through the lens 9 and the output window 10 is projected onto the slit AND of the monochromator. Another part of the luminous flux through the aperture 2 and the light guide 13 falls on the sensor 14 of the reference signal. Since the sample 7 with the heater 8, the illumination system 1, 2, 12, 13, 14, 15 and the optical system 3, 4, 5, 6 are rigidly interconnected, the reflection indicatrices are measured by rotating the sample 7 around its axis together with the illumination and optical systems relative to the lens 9. The modulator 12 is made in the form of a cylindrical cup with holes in the walls rotating around the incandescent lamp 1. The modulation frequency of the luminous flux is 400 Hz. Inside the modulator 12 there are two diaphragms 2, with the help of which the possibility of misalignment of the centers of the holes of the modulator with the optical axis is eliminated. Simultaneously, the diaphragms serve to prevent radiation from the inner walls of the modulator from entering the optical system. A light guide 13 is located on the opposite side of the mirror 3, at the end of which a sensor 14 of the reference signal is fixed, which can be installed, for example, with a photodiode FD-2. A modulator 12 with a radiation source 1 and diaphragms 2 is placed in a protective screen 15, in which there are two openings for the passage of the light flux. The protective screen 15 serves to protect the glass of the radiation source 1 from the destruction of non-metallic materials by pollution, and also excludes the possibility of direct radiation from the lamp 1 to the optical system of the device or the surface of the sample 7. Open the walls of the modulator, protective screen, radiation source, orifice plate and the light guide with the sensor of the reference signal are located on the same optical axis. The use of the lighting unit of the proposed design makes it possible to stabilize the luminous flux from the radiation source, to increase the scanning speed over the wavelength spectrum and to improve the measurement accuracy. At the same time, the error in determining the spectral reflectance coefficient by angles at high temperatures for alumina is ± 2Vo (in known devices ± 4-5%). 1. A device for determining the indicatrices of the spectral reflectance of translucent materials, including an optical system, a radiation source, a sample, a water-cooled screen with a heater located in it, and a modulator, in order to stabilize the light flux, to increase the scanning speed of a length spectrum waves and increase measurement accuracy, the radiation modulator is made in the form of a glass with holes in the wall with the possibility of rotation around the radiation source, inside the module Two diaphragms are fixedly mounted to limit the light flux on the mirror of the optical system, and a light guide with a reference signal sensor, the centers of the modulator openings, the radiation source, the aperture and the light guide with a reference signal sensor on the same optical axis. 2. The device according to claim 1, characterized in that the modulator is placed in a protective screen in which holes are made, which are located on the optical axis. Sources of information taken into account in the examination 1. Toporets A. S. A device for determining the indicatrix of the spectral reflectance. - “Optical-mechanical industry, 1961, № 4, p. 20. 2. USSR author's certificate for application number 2616112 / 18-25, cl. G 01 N 21/48, 1978 (prototype). L -fr: 4frg