RU2398252C2 - Optical transceiving device - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: device has spherical radome, a laser emitter, a plane mirror lying at an angle to the optical axis, and a lens which is optically connected to a photodetector, the signal from which is transmitted to a unit for receiving commands and processing information which is connected to the laser emitter launching input. The plane mirror has an axial hole through which laser radiation from the laser emitter passes. Radiation reflected from the plane mirror falls in the lens which is made in form of two optical branches. Between the optical branches there is an attenuator operating on the effect of violation of total internal reflection, whose control input is connected to one output of the unit for receiving commands and processing information which is fitted with a circuit for controlling the attenuator using the signal from the laser emitter.

EFFECT: increased protection of the device from intra-device flares and from the signal reflected from an object near the device.

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Description

The invention relates to optical instrumentation, in particular to optical-electronic devices for two-way optical communication, allowing the transmission and reception of optical radiation energy, and can be used in the development of systems operating in different spectral ranges.

A device is known that is described in the book of L.Z. Krikunov "Information System with Optical Quantum Generators", Kiev, published. “Technique”, 1970, p. 203, Fig. 107. The device contains a radiation source, a flat mirror mounted at an angle to the optical axis, a coaxially mounted spherical radome, a receiving lens and a photodetector (FPU).

The disadvantage of this device is that a significant part (depending on the material of the fairing from 5% to 10%) of the emitted laser stream, reflected from the spherical surfaces of the fairing, falls into the area of the radiation receiver. And since the power of the emitted laser stream is significant, even a small part of the stream reflected from the fairing, passing into the plane of the FPU by an unfocused beam, can lead to the failure of the receiver due to its high sensitivity.

The issue of combating intra-instrument flare (glare) has been resolved to some extent by the RF patent No. 2168751, G02B 23/00, publ. 11/23/2000, selected as a prototype. This optical transmitting and receiving device contains a radiation source, a flat mirror placed at an angle to the optical axis, a spherical fairing, a lens made in the form of a concave spherical mirror with a counter-mirror equipped with a screen, a FPU and an instruction receiving and information processing unit. In this case, the concave spherical mirror is located along the optical axis from the inner surface of the spherical fairing at a distance Δ satisfying the condition:

Δ≤F _rev + R,

where F _rev - the focal length from the inner surface of the fairing,

R is the radius of curvature of a concave spherical mirror.

However, in the prototype, the following disadvantages are noted.

The device’s functionality is limited, since it is possible to use such protection against intra-instrument flare only if the receiving lens is made according to a mirror-lens scheme.

Increased mass and dimensional characteristics while providing protection against glare. Since such devices are designed for the combined operation of independent devices (heat channel, visible channel and laser channel), it is usually necessary to achieve significant values from the inner surface of the fairing to the lens to ensure the functioning of the laser channel (receiving and transmitting device), and, therefore, to protect against intra-instrument flare (as described in the prototype), it is necessary to increase the radius of curvature of the spherical mirror of the receiving lens, which leads to an increase in its mass and size x parameters, and in accordance with the requirements for such a kind of devices, this is unacceptable.

In addition, this device cannot protect the FPU from a signal reflected from an object located in the immediate vicinity of the receiving and transmitting optical device.

The objective of the invention is the creation of a transmitting and receiving device that provides information from objects located in the field of view of the device at different distances from it, using its own radiation source.

The technical result, the achievement of which the present invention is directed, is to increase the protection of the device from both intra-instrument flare and radiation reflected from an object located in close proximity to the receiving and transmitting device.

The technical result is achieved due to the fact that in the transmitting and receiving optical device containing a laser emitter (laser), a flat mirror located at an angle to the optical axis, a spherical fairing, a lens, a FPU and a unit for receiving commands and processing information, made in the form of a block digital processing (BTSO), the lens is made in the form of two optical links, between which an attenuator is installed on the effect of violation of total internal reflection (ATR), while the flat mirror has an axial hole.

This design of the device allows you to adjust the intensity of the light flux incident on the attenuator, thereby protecting the FPU at the time of laser radiation from both intra-instrument illumination and radiation reflected from an object located in the immediate vicinity of the receiving and transmitting optical device.

The essence of the claimed device is illustrated by drawings.

Figure 1 schematically shows a receiving and transmitting optical device; figure 2 shows a timing diagram of the interaction of the digital processing unit, the laser emitter and the attenuator.

The device includes a laser emitter 1, a flat mirror 2 with an axial hole, a fairing 3, a lens 4-4 ', made in the form of two optical links (collimating and collecting), between which there is an attenuator 5, which is a shutter based on the ATR effect, which provides smooth adjustment of the intensity of optical radiation passing through the interference filter 6 on the FPU 7, and the command receiving and information processing unit 8, connected by one of the outputs to the control input of the attenuator 5, the other to the launcher input EPA 1.

Figure 2 shows:

9 - laser start pulse 1 coming from BCO 8;

10 - control pulse of the attenuator 5, coming from the laser 1 to BCO 8;

11 - laser radiation pulse 1;

12 - control pulse of the attenuator 5, coming from the CCO 8 to the attenuator 5 at a time τ earlier than the moment of the appearance of the pulse 11, while τ can take a maximum value equal to Δ ';

Δ 'is the programmable delay time of the radiation pulse 11 from the moment of appearance of the pulse 10;

T is the gate exit time for the ATR effect to the maximum transmission mode.

Transmitting optical device operates as follows. From the CCU unit 8, the laser start pulse 9 arrives at the laser emitter 1, after a while the laser 1 gives out an attenuator 5 control pulse 10 to the CCO 8. After a period of time Δ 'after the appearance of pulse 10, the laser emitter 1 sends a radiation pulse 11, and in time τ before this, the pulse 12 control the attenuator 5 is supplied to the attenuator. From the laser 1, the working light flux, passing through the axial hole of the flat mirror 2, the fairing 3, hits the target. At the same time, part of the working light flux is reflected from the spherical radome 3 and enters the plane mirror 2 in the form of a scattered reflected beam (inside the instrument), reflecting from which it falls on the attenuator 5, which at the moment has a transmittance K substantially lower than the maximum value. At the input prism of the attenuator 5 and its air gap, reflection of the inside-instrument radiation occurs, therefore, only a small part of it falls on the FPU 7. In the case when the reflected radiation arrives at the attenuator 5 from an object located in the immediate vicinity of the transmitting and receiving optical device, a continuously changing coefficient transmittance K does not reach its maximum value, and through a decreasing air gap of the attenuator 5 on FPU 7 only a part of the radiation reflected from a nearby the location of the object. During the period of time T, the shutter passes from a closed state, characterized by a minimum transmission of energy, to an open, at which the transmission is maximum. The signals from the FPU 7 are transmitted to the electronic unit (not shown in the drawing) and then to the unit for receiving commands and processing information (BTsO) 8.

When implementing the device, the shutter on the NPBO can be made in the form of two prisms transparent for radiation, the adjacent faces of which form a plane-parallel air gap with a thickness of several micrometer fractions. P-3 piezoelectric transducers are located on the truncated faces of the prisms.

Thus, the proposed device in comparison with the prototype is highly effective, since it retains all the advantages of the prototype and eliminates the failure of the FPU at the time of laser radiation from both inside illumination and radiation reflected from nearby observation objects.

Claims (1)

An optical transmitting and receiving device comprising a spherical radome, a flat mirror located at an angle to the optical axis, and a lens optically coupled to a photodetector, a signal from which is transmitted to an instruction receiving and information processing unit connected to a laser emitter start input, characterized in that the flat mirror has an axial hole through which the radiation of the laser emitter passes, and the radiation reflected from the flat mirror enters the lens, made in the form of two optical links between which an attenuator is installed on the effect of violation of total internal reflection, the control input of which is connected to one of the outputs of the command receiving and information processing unit, equipped with an attenuator control circuit based on a signal from a laser emitter.

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