RU2602398C2 - Laser unit - Google Patents

Abstract

FIELD: optics.

SUBSTANCE: laser unit has on one optical axis a laser radiation source, a power supply control input of which forms the first control input of the laser unit, an optical focusing and terminal element, as well as a photodetector, the output of which forms a data output of the laser unit. Photodetector is installed near the means for optical focusing to detect the laser radiation, which is reflected from its components-filter and collecting lens. Between the source of laser radiation and optical focusing mirror is made so that in one of its stable position provides direct passage of laser radiation in the terminal element, and in the other-its deviation in optical trap. Input of radiation direction control forms the second control input of the laser unit.

EFFECT: technical result consists in expansion of functional capabilities for controlling laser light with simplification of the measuring part of the laser unit.

3 cl, 1 dwg

Description

The invention relates to laser equipment and can be used in technological processes, data transmission systems, measuring equipment and other areas where the use of controlled laser exposure is required.

Laser blocks are known in which the evaluation of the intensity of laser radiation and its subsequent control is carried out. For example, in patent documents: [1] - EP 0674965 A1, B23K 26/03, B23K 26/02, publ. 10/04/1995, [2] - DE 102007053632 A1, B23K 26/42, G01J 1/42, G01J 4/00, publ. 05/20/2009, [3] - DE 102009052762 A1, B23K 26/42, publ. 05/12/2011, laser units of technological installations are presented, in which the laser beam coming from the laser source is deflected by a translucent mirror, then focused using optical elements and directed to the surface to be treated. The scattered light reflected from this surface passes in the opposite direction through the optical elements and a translucent mirror, focuses and enters the photodetector. The output of the photodetector is then used either simply to control the intensity of the laser radiation, or to generate control signals for laser radiation, which is carried out by exposing the laser source to the radiation, usually by turning off its power when a certain threshold value of the photodetector output is exceeded.

Closest to the claimed unit in its construction is a laser unit presented in US patent: [4] - US 4154529, G01D 3/36, publ. 05/15/1979 (Fig. 1), adopted as a prototype.

The prototype block contains a laser radiation source located on the same optical axis, the power control input of which forms the control input of the laser unit, the first optical focusing device and an end element, which is an optical fiber designed to output laser radiation to a consumer object and input radiation reflected from it . Between the laser radiation source and the first optical focusing means, there is a stationary oblique mirror with a hole for direct radiation from the laser radiation source, which provides a deviation of the radiation reflected from the consumer object in the opposite direction. Moreover, in the reflected radiation path included in the measuring part of the block, after the specified mirror, there is a second optical focusing device and a photo detector, the output of which forms the information output of the block.

The block prototype works as follows. The laser radiation generated by the laser source passes in the forward direction through the hole in the inclined mirror, then is focused using the first optical focusing means and enters the terminal element. From the same terminal element, in the opposite direction, reflected radiation is received, which is deflected with the help of an inclined mirror, then it is focused with the help of the second optical focusing means and fed to the photodetector input. The photodetector generates at its output an information signal characterizing the intensity of the reflected radiation, and also, through the conversion factor, the intensity of the direct radiation. This signal, as in analogues [1] - [3], can be used either simply to control the intensity of laser radiation (direct and reflected), or to generate a signal to control laser radiation, which is carried out by acting on the laser radiation source, namely by turning off its power when a certain threshold value of the photodetector output signal is exceeded.

Common to the prototype [4] and the above analogues [1] - [3] is that the implementation of the measuring part of the block is carried out using optical elements, which complicates the design of the block. Another disadvantage is that the means of the unit allow controlling laser radiation only by acting on the laser source itself, which is not always convenient according to operating conditions.

The technical result to which the claimed invention is directed is to expand the functionality for controlling laser radiation while simplifying the measuring part of the laser unit.

The invention consists in the following. The laser unit contains a laser radiation source located on the same optical axis, the power control input of which forms the first control input of the laser unit, optical focusing means and an end element, as well as a photodetector, the output of which forms the information output of the laser unit. In contrast to the prototype, a radiation direction control means was introduced between the laser radiation source and optical focusing means, which is designed in such a way that in one of its stable positions it provides direct transmission of laser radiation to the terminal element, and in the other, it deflects into the optical trap, and the photodetector mounted near the optical focusing means with the ability to register only that part of the laser radiation that is reflected from the components of the optical focusing means. The input of the radiation direction control means forms the second control input of the laser unit.

In a case of practical importance, the optical focusing device comprises a filter and a collecting lens located on the same optical axis, and the radiation direction control means is made in the form of a movable mirror linearly moving in the guides on sliding bearings driven by an electric drive, the control input of which forms the input radiation direction controls.

The invention and the possibility of its implementation are illustrated by the structural diagram of the laser unit.

The inventive laser unit in the considered exemplary embodiment comprises a laser radiation source 1 located on the same optical axis, the power control input of which forms the first control input of the laser unit, optical focusing means 2, consisting of two components - a filter 3 and a collecting lens 4, and an end element 5 , which, as in the prototype, is an optical fiber designed to output laser radiation to a consumer object.

The laser radiation source 1 is a solid-state laser with a pump diode and a power supply, the control input of which forms the power control input of the laser radiation source 1.

Filter 3 is a transparent plate made, for example, of SZS22 blue-green glass and is designed to exclude radiation from extraneous spectra, for example, infrared radiation from a solid-state laser pump diode.

The collecting lens 4 is designed to focus the laser radiation at the input of the terminal element 5, i.e. at the end of the fiber.

Between the laser radiation source 1 and the optical focusing means 2, a radiation direction control means 6 is arranged so that in its first stable position, the laser radiation is directly transmitted through the optical focusing means 2 to the terminal element 5, and in the second, its deviation to the optical a trap 7, while the input of the radiation direction control means 6 forms a second control input of the laser unit.

Structurally, the radiation direction control means 6 can be implemented, for example, in the form of a movable mirror linearly moving in guides on sliding bearings driven by an electric drive, the control input of which forms the input of the radiation direction control means 6.

The optical trap 7 is designed to absorb light radiation and is a surface of a certain geometric shape, such that the radiation incident on it is not reflected from it. Such traps are described, for example, in patents: [5] - EP 2602645 B1, G02B 5/00, publ. 03/26/2014, [6] - US 4864098, B23K 27/00, publ. 09/05/1989, [7] - US 7374298 B2, G02B 27/00, publ. 05/20/2008.

The laser unit in its measuring part contains a photodetector 8, the output of which forms the information output of the laser unit. A photodetector 8 is installed near the optical focusing means 2 with the possibility of detecting only that part of the laser radiation that is reflected from components 3 and 4 of the optical focusing means 2.

The operation of the laser unit is as follows.

Before turning on the source of laser radiation 1 (before turning on its power supply) at the output of the photodetector 8, i.e. at the information output of the laser unit, there is no information signal and the radiation direction control means 6 is in its first stable position.

The inclusion of the source of laser radiation 1 is carried out by applying to its input power control (first control input of the laser unit) of the corresponding enable signal. After the laser radiation source 1 is turned on, laser radiation is generated at its output, which enters the input of the optical focusing means 2, passes through it through a filter 3, and a collecting lens 4 and then enters the terminal element 5. A part of this radiation, partially reflected from these components 3 and 4 means 2 of optical focusing, is recorded (fixed) by the photodetector 8. At the output of the photodetector 8, a signal is formed that characterizes the intensity of the reflected radiation. This signal directly depends on the intensity of the laser radiation generated by the source 1.

The signal generated by photodetector 8 can be used either simply to control the intensity of laser radiation, or to generate signals based on it to control laser radiation, which is carried out using means external to the claimed laser unit (not shown in the structural diagram).

The proposed control of laser radiation in the inventive laser unit is carried out by applying an external control signal generated on the basis of the output signal of the photodetector 8 to the input of the radiation direction control means 6 (second control input of the laser unit). Under the influence of this control signal, the radiation direction control means 6 is transferred to a second stable position, at which the laser radiation is deflected into the optical trap 7. In this case, almost instantaneous removal of radiation from the terminal element 5 is provided.

If necessary, depending on operational requirements, the laser radiation source 1 itself can also be turned off by supplying a corresponding shutdown signal generated on the basis of the output signal of the photodetector 8 to the power control input of the laser radiation source 1 (first control input of the laser unit).

The possibility of generating, in the laser unit of the proposed design, an output information signal sufficient to control the intensity of the laser radiation and generate laser control signals based on it, is confirmed by an experiment conducted at the Department of Applied and Computer Optics of the St. Petersburg National Research University of Information Technologies, Mechanics and Optics . So, during this experiment, the radiation from the LSR445NL-1W laser module passing through a 1 mm thick SZS22 blue-green glass plate was detected by a sensor (photodetector) located next to the plate, which was played by the compact solar battery SC3030S-3NA, while the potential difference at the sensor contacts, controlled by the UT30D combined instrument, was 1.22 V. This signal level is sufficient to monitor the intensity of laser radiation and generate laser control signals based on it nym radiation.

Thus, the above shows that the invention is feasible and gives a technical result, which consists in expanding the functionality for controlling laser radiation while simplifying the measuring part of the laser unit.

Information sources

1. EP 0674965 A1, B23K 26/03, B23K 26/02, publ. 10/04/1995.

2. DE 102007053632 A1, B23K 26/42, G01J 1/42, G01J 4/00, publ. 05/20/2009.

3. DE 102009052762 A1, B23K 26/42, publ. 05/12/2011.

4. US 4154529, G01D 3/36, publ. 05/15/1979.

5. EP 2602645 B1, G02B 5/00, publ. 03/26/2014.

6. US 4864098, B23K 27/00, publ. 09/05/1989.

7. US 7374298 B2, G02B 27/00, publ. 05/20/2008.

Claims (3)

1. A laser unit containing a laser radiation source located on one optical axis, the power control input of which forms the first control input of the laser unit, optical focusing means and an end element, as well as a photodetector, the output of which forms the information output of the laser unit, characterized in that between a laser radiation source and optical focusing means have been introduced means for controlling the direction of radiation, made in such a way that in one of its stable position provides It allows direct laser radiation to pass through to the end element, and in the other, it deviates into an optical trap, and the photodetector is installed near the optical focusing means with the possibility of detecting only that part of the laser radiation that is reflected from the components of the optical focusing means, while the input of the radiation direction control means forms the second control input of the laser unit. 2. The laser unit according to claim 1, characterized in that the optical focusing means comprises a filter and a collecting lens located on the same optical axis. 3. The laser unit according to claim 1, characterized in that the radiation direction control means is made in the form of a movable mirror linearly moving in guides on sliding bearings driven by an electric drive, the control input of which forms the input of the radiation direction control means.