SU783599A1 - Photometer - Google Patents

Description

The invention relates to the field of photometry and is intended for the xytrol and measurement of the properties of photographic materials or their production, as well as for various fields of science and technology, where reps should be replicated in the density of photoemulsions (cut parameters of images or other fictional phenomena ska x-ray technology, photograph, etc.). One of the well-known photometers contains successively installed light sources, a beam-splitting device, an optical interrupter, a photo-receiver and a registration 1J analyzer. The disadvantage of such a device is limited accuracy. The closest to the invention technical KIM solution is a photometer containing sequentially installed sources, a beam-splitting device, an optical chopper, a photodetector, two parallel-connected selective filters and a recorder 2. The disadvantage of the device is The accuracy and sensitivity of the measurement is comparatively low due to the nonlinearity of the amplitude characteristic. the patterns of the ussdtel and the drift amplifier. The aim of the invention is to improve the accuracy and integrity. To achieve this goal, in a known device, the recorder is designed as a phase meter. FIG. 1 shows a block diagram of the proposed device; in fig. 2 - dependence of the initial phases of the harmonic components on the frequency; in fig. 3 - Dependence of the relative phase change on the transmittance. The device comprises a light source 1, a beam-splitting device 2, an interrupter 3, a photometric sample 4, a photodetector 5, selective filters 6 and 7 and a phase meter 8. The device operates as follows. The luminous flux from the light source 1 is divided into two streams by the beam-splitting device 2: the measuring F1 and the reference flux are fed to the interrupter 3, which at the first moment of time passes a reference signal F to the photodetector at

equal to the first - measuring f | and in the third no stream is connected. The measuring luminous flux passes through the photometric sample 4 and, together with the reference, enters the photodetector 5, where it is converted into an electrical signal. The signal from the photo light is fed to selective filters 6 and 7 that are tuned to the appropriate frequencies. The selected harmonic components are represented by a phase meter 8, which measures the times. The phase is between the selected harmonic years (the parts. By the magnitude of this difference, one can judge the presence, sign and optical density of the sample under investigation (Fig. 2). The dependence of the irrigation change of the initial phase on the transmittance f ff

The initial phase of the harmonic component and the dependence on the transmission coefficient, the duration of the signal Tjj, and the frequency is expressed by the effective formula

.ots: (i) V.f,

Jk

From the graph in FIG. 3 that the relative changes in the initial phase versus transmittance are different. So for Tj, f 0.7 this dependence is linear, and at T, jf 0.7 it is a sensitivity. the relative phase change increases dramatically. So if you set the filter to a frequency of 0.95, then when the transmittance changes by 10%, the phase changes by 40%.

The invention makes it possible to eliminate the effect on the measurement accuracy of the nonlinearity of the amplitude characteristic of the photoconverter and its drift.

Claims (2)

1. US patent number 3887281, class, G 01 J 3/42, published. 1975. 2. Authors certificate of the USSR N 88249, cl. G 01 L / 36, 1950 (prototype). i 0.6 0 0.1 0.2 a 0.6 0.8 1 r 9ijf2. FIG. 3