SU587343A1 - Spectrum instrument - Google Patents

Description

(54) SPECTRAL ORIBOR

one

The invention relates to spectral instrumentation, which can be used, for example, in infrared spectrophotometers.

Spectral instruments are known, containing a dispersing element — a diffraction grating, a scanning drive for rotating it, sets of replaceable filters (interference), switching filters for each set, and a receiving-regimenter.

In large-scale field devices of this type, to prevent distortions in the recorded spectrum, the filters change when the scan is stopped, which means that the whole spectrum is recorded and the instrument is more complex.

Closest to the proposed spectral device, which contains a {{1spergiruyuschiy} element, an adjustable scanner drive, sets of replaceable filters, filter switching drives, and a recording device. Its drawback is the spectrum recording upon switching ({zltr.

The purpose of the invention, the elimination of spectral detection bones during filter switching, is achieved by introducing means for adjusting the switching speeds into a known spectral instrument.

The drawing shows the functional diagram of the device

The spectral instrument contains a dispersing element (diffraction grating) 1, an adjustable scanning drive, i.e. the drive of the dispersing element, which includes, for example, the executive stepping motor 2, the speed controller of the spectrum 3, which is a switch for selecting the required speed 1 and the input of the dispersing element, the generator 4 of control pulses and the electronic switch 5 switching current in the windings stepper motor 2. fe device with also optical elements, schematically depicted in the form of mirrors 6, forming an optical channel with specified cross-sectional dimensions, and a recording system 7 To eliminate the scattered light and, the highest order of the spectrum in the device, a set of reflective filters 8 mounted on a rotating holder 9 and a set of interference filters 1O mounted on a rotating holder 11, Rotary holders 9 and 11 of reflective and interference filters drives 12 are installed. and 13 independent movements, for example, rotation, of each holder that contains actuating motors, for example, direct current 14 and 15, and shutdown mechanisms 16. The shutdown mechanisms are provided with contact groups (on ) Tezhe not shown), each of which corresponds to a single filter 8 ,. 1Q. The actuators 12 and 13 of the independent rotation of the filter holders are diverted from each other, mainly by the number of mechanisms 16 for switching off the corresponding filters in the set. A command device 17, such as a cam base with microswitches installed in the device, serves to generate the filter switching commands in a specific pattern. It is associated, for example, with a kinematically rigid connection with the rotational drive of the dispersing alemate. The input of the command device is connected by means of controlling the speed of independent rotation of the filter holders, which are, for example, controller 1. connected between generator 4 and command device 17, in combination with converters 19 and 2O, the conversion factors of which are chosen depending on the required rotation speed of filter holders. Converters 19, 20 are connected by their inputs to the output of the command device 17, and by outputs to the drives of independent rotation of the filter holders. The device also contains a deceleration device 21, which reduces the speed (sweeps of the spectrum in the absorption bands. The spectral device operates with the following. The regulator 3 is set to the desired scanning speed of the spectrum. The generator 4 generates a sequence of pulses whose frequency depends on the position of the regulator The pulse sequence of the generator 4 is converted by the electronic switch 5 into a multiphase pulse system which controls the stepping motor 2 and turns the dispersing electron The radiation flux generated by the optical elements 6 passed through the reflective and interference filters recorded by the receiver-recording system 7, which also controls the scan speed slowdown device 21, which reduces the frequency of the oscillator a 4 when scanning the bands nlnnn in the absorption spectrum Since the shaft of the stepper motor 2 is rigidly connected with the mechanism of the command device 17, the cam system of this device generates commands for turning on the motors 14 and 15 in ashiyh spectrum. When the engine 14 or 15 is turned on, a smooth turning of the corresponding holder 9 of the cylinder 11 begins, i.e. changing the filters in set 8 or 1О without stopping the scan drive. The spectrum of rotation of the holders 9, 11 should be optimal from the point of view of the accuracy of the spectrum recording so that the feed switching time T is within D / iO / l ("where Y is the scanning speed} g9 is the overlap of the transmission areas of adjacent filters, i.e. interval in which both filters have sufficiently high transmittance (for example, less than 0.5-O, 8) {-frequency of switching optical channels in dual-channel devices ILE 1 streaming in single-channel. Maintaining switching times within optimal limits and changing the scanning speed is provided by the connection of the regulator 18 with the generator 4, which determines the scanning speed. Dependence of the filter switching speed on the overlap of the transmission areas of adjacent filters, which may be different for the filters of different sets, is realized by converting the converter 19, 20 with the respective conversion factors. After installing the filters in the desired position, the motors 14 and 15 are switched off by mechanisms 16 equipped with contact groups. It is advisable to make the overlap of the optical channel with non-optic jumpers of the holders 9, 11 during the switching of the filters small. In most cases, it is desirable that attenuation of the radiation flux by bridges does not exceed 30%. When these conditions are fulfilled, the filter JMJs are switched almost without any reduction in the registration of the specialist. Smooth switching of filters without stopping the scan drive allows for the continuity of the recording of spectral information and thereby shortens the overall recording time. ; This is

The bin is important in devices with a wide spectral range using a large number of filters.

Claims (2)

1. The US patent in 3322941, cl. 356/100, 1974. 2. Infrared spectrophotometer IKS-2 Technical specification. L., LOMO, 197O,