Laser-focusing head with zns lenses having peripheral thickness of at least 5 mm and laser cutting apparatus and method using one such focusing head

FIELD: physics, optics.

SUBSTANCE: invention relates to a laser beam focusing head for laser cutting, a method and an apparatus for laser cutting of a metal component. The focusing head comprises a collimating lens (13) and a focusing lens (14). The collimating lens (13) and the focusing lens (14) are made of ZnS and have peripheral thickness of at least 5 mm. A deflecting mirror (15) operating at an inclination angle (α) from 40° to 50° is placed between the collimating lens (13) and the focusing lens (14) on the path of the laser beam. The laser cutting apparatus comprises a solid-state laser device (SL) emitting a laser beam with wavelength of 1.06 mcm to 1.10 mcm and power of 0.1 kW to 25 kW, said focusing head and a conveying fibre (CF) connecting the solid-state laser device (SL) and the focusing head.

EFFECT: invention provides a stable focusing position of a laser beam during cutting.

13 cl, 5 dwg, 1 tbl

 

The invention relates to a particular optical configuration used in the cutterhead of a solid state laser, in particular a fiber laser, allowing to control the focal issues of displacement and damage to the laser optical system, the focusing head, laser unit, equipped with such a focusing head, in particular the installation of a fiber laser doped with ytterbium.

The LEVEL of TECHNOLOGY

A new generation of solid-state lasers such as fiber laser or disk laser has many advantages and combines the power levels of several kW with excellent quality factor or BPP (beam quality parameter), unlike solid-state lasers, such as lasers Nd:YAG.

In addition to the properties, in accordance with which these lasers are sources, suitable for cutting metal materials, in this case, the wavelength (of 1.07 µm), which is smaller than the wavelength of the lasers on the basis of CO2(10.6 μm), is better absorbed by the metal and is better tolerated by the optical fiber, reduced overall dimensions, high reliability and high brightness greatly improve the performance of cutting metallic or non-metallic materials.

Typically, the setting of cutting on the basis of the fiber laser includes a laser source and optical apparatus for the transmission of the manhole�tion of the beam to the cutting head, also called a focusing head which provides focusing of the beam on the thickness of the part.

The laser source is a fiber laser with a mixture of ytterbium (Yb), equipped with at least one optical fiber for transmission of the beam, and the cutting head contains optical device for collimation, redirection and focus, allowing you to deliver a focused laser beam cut straight to the details.

Optical devices, such as a focusing lens in the cutting head of the laser must be able to withstand high surface power density, typically from 1 to 10 kW/cm2depending on the characteristics of the laser source and the beam diameter on optical systems, which makes them more fragile during continuous operation in a contaminated environment, which impairs their.

In the continuous mode of laser radiation damage of optical systems is expressed mainly in the form of a degradation of optical systems, initially with no visible damage. This deterioration occurs essentially due to temperature effects.

In fact, the residual absorption of surface coatings and substrates of optical systems leads to non-uniform heating of the optical components and the accumulation of thermal stress, in private�ti, for transmission components, such as lenses. These mechanisms affect the characteristics and quality of the laser beam and after a long period of radiation damage of optical systems: the appearance of burn marks, flaking of the coating, etc.

The heating of the optical systems of the cutting head is also offset DF from the point of focus of the beam associated with the effect of thermal lensing, also called focal shift, which is illustrated in Fig. 1. When exposed to the lens 1 the center is heated by a laser beam 2, is collimated with a large capacity and deliver on the optical axis (AO), while the edges stay cooler. In the lens 1, a radial temperature gradient. The magnitude of this gradient is greater, the higher the power density received by the lens 1. This temperature gradient creates a gradient in the refractive index of the material. This phenomenon, combined with the effect of thermal expansion of the material of the lens 1, leads to the change of the effective radius of curvature of the lens 1 and change its focusing characteristics. The original focal plane (PFI) of the beam, located at a distance F from the lens, is moved along the direction of propagation of the beam, becoming closer to the focusing lens 1, the distance F until it reaches the shifted focal plane (PFD). �ATEM initial focused beam (FFI) is converted into a focused beam offset (FFD), with worse specifications cutting.

Surface contamination of the optical systems as a result of environmental influences, in other words, dust, or metal protrusions of humidity, and aging are factors that increase the absorption of the lens and gradually increase the heating phenomenon, leading over time to an increase in the amplitude of the focus offset.

Currently the performance characteristics of industrial laser cutting method is determined on the basis of cutting speed, cut quality - i.e. flat, smooth and stable surface section and the permissible deviations of the operating parameters of this method.

Method of laser cutting fiber laser sensitive to changes in position of the focal point of the beam relative to the surface of the workpiece, especially when it comes to cutting very thick plates, namely from 4 mm and above. Permissible deviation from the position of the focal point is typically +/-0,5 mm. If the focal position of the laser beam is changed in a big way from tolerance, optimum implementation of the section next to impossible.

Thus, the challenge is to find new settings section to compensate for the focal shift, or replacing an optical system of the focusing head. Hence nigeriaeducational automated commercial method.

The essential problem is that if the focal point is changed during the cutting operation, it will lead to uneven implementation of the cut in different parts or even on different surfaces of the same details.

The phenomena described above show that the duration of the method of cutting is strongly linked to the strength of the optical systems for the distribution of the laser beam. Because the location of the focal point is an important parameter of a method of cutting fiber laser, it is important that the focal position of the beam was as stable as possible, and ensure that the movement remained within acceptable limits. Thermal deformation, affecting the optical elements must be minimal at high power to avoid damaging them. When choosing optical systems, forming a system of focusing head for the laser cutter, all of these requirements must be taken into account.

In addition, the problem also lies in the difficulty of transmitting the laser beam with high brightness for use when cutting. Available power levels of laser radiation continue to increase, but the strength of optical devices limits the power levels that can be used when cutting. In fact, the rays with high brightness are characterized by a high level�mi power combined with excellent quality coefficients, i.e. small values of the CDF, for example, about 0.33 mm·mrad. This implies a very high power density on the surfaces of optical systems focusing heads, and the increase of the temperature gradients and thermal deformation. It was also found that the durability of optical materials to damage caused by lasers with high brightness, worse than the damage caused by conventional laser-based CO2as a shorter wavelength of lasers with high brightness sensitive stronger to existing deficiencies in substrates and surface coatings of optical elements that may cause excessive local heating.

Disclosure of the INVENTION

Thus, the task that needs to be addressed is the management of the above-mentioned problems of the focal displacement and damage to optical systems arising from the application of solid-state lasers, in particular, when using a fiber laser, in particular a fiber laser, ytterbium-doped, to ensure long-lasting cutting performance, in particular, in applying the method of laser cutting with high power, i.e. with a capacity of at least 1 kW.

The solution, according to the present invention, consists in focusing a laser beam head for laser cutting metal parts, containing�her collimating lens (13) and a focusing lens (14), thus collimating lens (13) and focusing lens (14) is made of ZnS and has a thickness on the edges of at least 5 mm, and a deflecting mirror (15) is located between the collimating lens (13) and a focusing lens (14) in the path of the laser beam in said focusing head so that the laser beam has an angle (α) is the reflection from 40° to 50° from the deflecting mirror (15).

The present invention also relates to an installation for laser cutting of metal parts containing:

- solid-state laser device that emits laser light with a wavelength of 1.06 μm to 1.10 μm and a power of 0.1 kW to 25 kW,

- focusing the laser beam to the laser head for metal cutting according to the first aspect of the invention the preceding paragraphs, and

- transmitting fiber connecting the solid-state laser device and a focusing head so as to bring the laser beam emitted by the solid state laser device, a focusing head.

Depending on the installation situation, according to the present invention, may contain one or more of the following features:

- solid-state laser device is a plan view of a fiber laser, preferably a fiber laser doped with ytterbium;

- solid-state laser device emits a laser beam with power ranging from 1 kW to 5 kW cont�Ohm, quasi-CW or pulsed mode, preferably in a continuous mode;

- transmitting fiber has a diameter that does not exceed 150 μm, preferably 50 μm or 100 μm;

- solid-state laser device emits a laser beam with BPP from 1.6 to 4 mm·mrad;

- transmitting fiber has a diameter of 50 μm and CDF from 1.6 to 2.2 mm·mrad, and the collimating lens has a focal length from 70 mm to 120 mm, and the focusing lens has a focal length of 200 mm to 450 mm. More precisely, in the case of the transmitting fiber with a diameter of 50 μm, CDF from 1.6 to 2.2 mm·mrad, the focal length collimating lens is from 70 mm to 120 mm, preferably from 70 mm to 90 mm. to cut the material, the thickness of which is strictly less than 10 mm, the magnitude of the focal length of the focusing lens is predominantly from 200 mm to 300 mm, preferably from 220 mm to 280 mm, for cutting material thickness higher than or equal to 10 mm, the value of the focal length of the focusing lens is predominantly from 350 mm to 450 mm, preferably from 380 mm to 420 mm;

- transmitting fiber (FDC) has a diameter of 100 μm and CDF from 2.6 to 4 mm·mrad, and the collimating lens has a focal length from 130 to 180 mm, and the focusing lens has a focal length from 200 to 450 mm. More precisely, in the case of the transmitting fiber having a diameter of 100 μm, CDF Coto�CSOs from 2.6 and 4 mm·mrad, focal length collimating lens ranges from 130 mm to 180 mm, preferably from 140 mm to 180 mm. to cut the material, the thickness of which is strictly less than 10 mm, the value of the focal length of the focusing lens is predominantly from 200 mm to 300 mm, preferably from 220 mm to 280 mm, for cutting material with a thickness higher than or equal to 10 mm, the value of the focal length of the focusing lens is predominantly from 350 mm to 450 mm, preferably from 380 mm to 420 mm;

- focusing lens has a focal length of 200 mm and 450 mm.

In addition, the present invention also relates to a method of laser cutting metal parts, which used a laser cutting machine according to the present invention.

BRIEF description of the DRAWINGS

The present invention which, in particular, reveals the specific optical configuration used in the cutterhead of a fiber laser, this becomes clear when considering the following detailed description and the attached drawings, in which:

Fig. 2 shows a basic diagram of a conventional optical system for the cutting head and the characteristics of the laser beam propagating through the optical system,

Fig 3 schematically shows the principle of the unit and the laser cutting method according to the present invented�Yu,

Fig. 4 shows a comparison of the changes of position of the focal point of the beam by laser radiation from the lens system, made of ZnS, and a system of lenses made from fused silicon (Si), and Fig. 5 shows a comparison of the changes of the focal point position of the beam focused by the lens system of ZnS, which includes the collimating lens with the thickness at the edges of 2 mm, and the collimating lens with the thickness at the edges of 7 mm.

The IMPLEMENTATION of the INVENTION

The cutting installation according to the present invention comprises a solid-state laser source SL, equipped with at least one optic fiber FDC, the transmitting beam, and a focusing head 3, also called a cutting head, for moving and focusing the laser beam FL to be cutting part 10 or in it. Features and range of operation of the installation are explained further and illustrated in Fig. 3.

The cutting head 3 contains optical device for collimation, redirection and focusing of laser beam.

In addition, the laser beam is emitted from the solid-state laser device or generator, preferably a fiber laser with a mixture of ytterbium (Yb). In this laser device, the laser, namely the phenomenon of light amplification, which is used for generating laser radiation, is achieved through increase�her environment preferably pumped with laser diodes and formed by one or usually several doped optical fibers, preferably silica fibers with a mixture of ytterbium.

The wavelength of the radiation output from the laser is 1.06 μm to 1.10 μm, and the laser power is between 0.1 kW and 25 kW, usually between 1 kW and 5 kW.

The laser can operate in a continuous, quasi-continuous or pulsed mode, but, according to the present invention, preferably, the laser worked in a continuous mode, since we are talking about the strongest radiation mode for the cutting head optics.

The beam generated by a solid-state laser source is emitted and transmitted to the focusing head, through at least one optical transmission fiber, is made of undoped silicon, with a diameter less than 150 μm, for example equal to 50 μm or 100 μm.

In General, the use of the laser source with high brightness, such as a fiber laser, allows you to generate beams of high power with a great rate.

The degree of quality of the laser beam is measured by its quality factor or parameter of the beam quality (BPP). CDF is determined by the characteristics of the laser source SL and a diameter of the transmitting fiber FDC. He expresses�I as the product of the radius w 0in narrowing the focus of the laser beam half-angle of divergence θ0as shown in Fig. 2. CDF also be determined as the product of the radius wfiboptical transmitting fiber emitting a laser beam, a half angle of divergence θfibbeam at the exit of the fiber. Thus, for the fiber 50 µm BPP of the beam is usually from 1.6 to 2 mm·mrad, while for a 100 µm fiber, CDF is normally from 2.7 to 4 mm·mrad.

As shown in Fig. 2, the system to focus laser cutting head comprises, in series in the propagation direction of the laser beam, at least one collimating lens LC, allowing to obtain a collimated beam FC on the basis of the diverging beam FD, and at least one focusing lens LF, allowing to obtain a focused beam of FF and concentrate the energy of the laser cut parts. Focal length collimating lens and the focusing lens are selected so as to obtain a focal spot with a diameter necessary to provide cutting parts power density.

The diameter 2w0beam in the focal plane is defined as the product of diameter 2wfibfiber optical zoom G system focus, and is expressed as follows:

where - G is defined relative�, making it the focal distance F focfocusing lens FC to the focal length Fcolcollimating lens LC; and

- w0and wfibare the characteristic radii of the beam in the focal plane and the fiber, respectively. Under the characteristic radius w refers to the distance from the optical axis where the intensity drops as 1/e2(about 13.5%) of its maximum value, which means that 86.5% of the beam energy lies in the disk of radius w. All the parameters of the beam are defined according to this criterion.

The radius of the beam emitted by the collimating and focusing optical systems is determined by the following relationship:


Half of the divergence angle θfibbeam, emitted by the transmitting fiber, derived from the values of the BPP of the focused beam through the following relation:

The average power density per unit area, also called power density (DP) emitted from the optical systems is expressed in kW/cm2and is defined as follows:

where Plasis the total energy of the radiation emitted by a laser source, a wcolrepresents a characteristic radius of the beam impinging on the optical system.

Thus, understand the problems that arise when �ispolzovanie laser generator, high brightness, such as fiber laser, namely:

- this type of source is characterized by weak CDF and, thus, the rays having weaker divergence θfibat the output fiber. This parameter corresponds to the speed of propagation in the remote field of the beam emitted by the transmitting fiber, and determines the beam diameter on the optics of the system. At the same focal length collimating the beam of higher quality and therefore more weak divergence has a smaller diameter 2wcolon the collimating lens. Hence the increase in DP. In the recommendation for the following table 1 gives comparative characteristics of conventional beam for different lasers, as well as the density of the received power at the optical systems for the power of 2 kW and focal length collimating lens, equal to 100 mm;

- with the same optical magnification of the laser beam with a smaller CDF focuses with the same focal length has a smaller diameter and the divergence θ0. Its Rayleigh length zR=w00is greater. Meanwhile, the displacement of the focal point caused by heating of the focusing system with a large capacity, is proportional to zR.

The table shows that the power density on the lenses increases with increasing beam quality.The amplitude of the temperature gradient, mounted in optical systems under the influence of laser radiation increases with the density of the power supplied to the optical system. Thus, to avoid problems, the focal displacement and damage to the laser, it is preferable to work with optical systems having the best possible temperature characteristics.

To this end the optical system according to the present invention combines certain properties described below, as shown in the diagram in Fig. 3.

The cutting head 3 is composed of optical devices for transmission, i.e. here the lenses 13, 14 are used for operations collimation (13) and focus (14) of the beam FL laser emanating from the transmitting fiber and the generated solid-state laser source SL.

Preferably use zinc sulfide (ZnS) as a substrate for collimating lens 13 and the focusing lens 14. This is because the amplitude of the temperature gradient, which appeared in the lenses under the influence of laser radiation, is inversely proportional to thermal conductivity of the material constituting the lens. Thus, thermal conductivity of ZnS (0.272 W/cm/°C) is approximately 20 times more thermal conductivity of fused silica (0,0138 W/cm/°C). This increased conductivity increases the ability of ZnS heat output and reduces the amplitude of the gradients of temperature and �elovich deformations, caused in the lens limited radiation with a large capacity.

Mentioned optical collimating device 13 and the optical focusing device 14 may be selected among various types available lenses. The lenses are preferably singlets to limit the number of optical surfaces of the system to focus and minimize the risks of damage. Can be used in different geometry of the lens, for example, PLANO-convex, biweekly or convexo-concave shape. Preferably, used PLANO-convex lens. All optical surfaces are preferably possess antireflective coating reflective at the laser wavelength.

Lens cutting head is placed in a thermally adjustable holder. The water circulating in the holder, provides cooling by indirect contact with lenses. The water temperature is maintained between 19°C to 25°C.

The thickness and diameter of the lenses 13 and 14 have the same effect on their thermal characteristics. The larger the lens, the better the dissipation of heat through the colder peripheral areas and smaller temperature gradients. In conventional cutting heads use lenses with a large thickness, i.e. the thickness of the edges of at least 5 mm, only for the operation of focusing. This is due to the fact that the auxiliary gas is expelled �neposredstvenno after the focusing lens, thereby subjecting it to strong pressure. Focusing lens must, therefore, have to be fat to have suitable mechanical resistance. In the framework of the present invention, to reduce the phenomenon of the focus offset used thick lenses for beam collimation and focusing. Unlike conventional head, the cutting head 3 consists, therefore, of lens thickness at the edges is equal to at least 5 mm, preferably 6 to 8 mm. Also, since a large thickness improves thermal characteristics, optical system with large diameter better bring the heat on the edges. Whatever the size of the beam impinging on the optical system of the cutting head 3, it uses a lens with a diameter of from 35 to 55 mm.

In the cutting head 3 reflective component 15 is located on the path 10 of the laser beam between the collimating lens 13 and the focusing lens 14. This component is a flat mirror and does not change the beam propagation parameters. The mirror substrate is made of fused silica.

At least one mirror surface covered with a reflective layer. This layer is formed of a thin optical layers and reflects light with a wavelength of laser beam cutting, and with a wavelength of from 630 nm to 670 nm. The coating is, however, transparent to visible and infrared� region of the spectrum, including the wavelength of the illumination system, for example, for a laser diode. Thus, it is possible to attach a device management method (type of camera or photodiode) behind the mirror. It provides a reflection of the laser beam at the angle α of the reflection from 40° to 50°, preferably 45°. The thickness of the mirror is from 3 mm to 15 mm, preferably 8 to 12 mm. This mirror allows first of all to reduce the vertical dimension of the head to enhance the mechanical strength. Moreover, in this configuration, the transmitting fiber is held horizontally, which reduces the risk of dust during the operations of mounting and demounting of the fibers or of the collimator. Finally, reflecting the integration component for the beam path to compensate for the focal shift caused by lenses. In fact, the longitudinal movement of the focal point caused by a reflective component, in the direction opposite to the focal shift caused by the transmitting component.

Lens cutting head 3 is also characterized by certain focal lengths adapted to CDF used the transmitting fiber. These focal lengths are needed to obtain the focal spot diameter 2w0suitable for cutting the material. For the transmitting fiber diameter of 50 μm CDF beam usually�is from about 1.6 to 2.2 mm·mrad. For this fiber the focal length collimating lens is 70 to 120 mm, preferably from 70 to 90 mm. the Choice of the focal length of collimating lens determines the focal length of the focusing lens depending on the desired optical zoom cutting thickness of material being processed.

For materials, thickness strictly less than 10 mm, the focal length of the focusing lens ranges from 200 to 300 mm, preferably from 220 to 280 mm. For materials having a thickness greater than or equal to 10 mm, the focal length of the focusing lens varies from 350 mm to 450 mm, preferably from 380 mm to 420 mm.

For a transmission fiber with a diameter of 100 µm BPP beam typically ranges from 2.6 to 4 mm·mrad. For this fiber the focal length collimating lens ranges from 130 mm to 180 mm, preferably from 140 mm to 180 mm. For materials with a thickness strictly less than 10 mm focal length focusing lens is from 200 mm to 300 mm, preferably from 220 mm to 280 mm. For materials having a thickness greater than or equal to 10 mm, the focal length of the focusing lens is from 350 to 450 mm, preferably from 380 to 420 mm.

In the focusing head 3 is supplied auxiliary gas through the inlet 5 for gas, made in the wall indicated the focusing head 3, through which the gas or gas mixture flows p�d pressure from the gas source, for example, from one or more gas cylinders, storage tanks or from one or more gas lines, such as gas distribution system, and introduced to the inlet nozzle 4 and discharged through the nozzle 4 in the direction of the workpiece 30, cut by a laser beam.

Auxiliary gas is used to remove the molten metal from the slots 12 section obtained by melting of metal by means of a laser beam FL that focuses in position 11 relative to the surface being cut details 10.

The choice of gas is dependent on the characteristics of the material being cut, in particular, from its composition, type and thickness. For example, for cutting steel may be used air, oxygen, a mixture of nitrogen/oxygen or helium/nitrogen, while nitrogen, mixtures of nitrogen/hydrogen or argon/nitrogen can be used to cut aluminum or stainless steel.

In fact, laser cut detail 10 may be formed from various metallic materials such as steel, stainless steel, mild steel or light alloys, such as aluminum and its alloys, even titanium and its alloys, which usually has a thickness of from 0.1 mm to 30 mm.

In the method of cutting the laser beam can be focused (11) in the thickness or on one of the surfaces of the part 10, or close to it, i.e. on the outside and a few mm above or below �t its upper surface 10A, or the lower surface 10b, or on the surface 10A or the lower surface 10b. Preferably, the position of the 11 focal point is at a distance of 5 mm above the upper surface 10a and 5 mm below from the lower surface 10b of the workpiece 10.

Thanks to the present invention, the focus position of the laser beam stably retained during the cutting process, it is possible to avoid or to minimize any focal offset and any damage to the optical system that essentially guarantees constant performance throughout the laser cutting operation.

It is preferable to use one or more lenses of ZnS than that of fused silica, as demonstrated when comparing the focal shift caused by exposure to high power on these two types of lenses.

For this purpose we compared two optical systems, each of which consists of a single collimating lens with a focal length of 80 mm and a single focusing lens 250 mm. One system contained ZnS lens and the other of fused silica.

The caustic of the laser beam, focused by each system were recorded using a beam analyzer. This device measures the radius of the beam, for which 86% of the laser power is contained in the disk of this radius on consecutive planes of propagation at a distance �roughly 10 mm on either side of the narrow focused beam.

On the basis of registered caustics is possible to determine the position of the focal plane of the laser beam along the direction of its propagation. Changing the position of the focal plane during prolonged exposure to the focusing optical system can occur when you perform a series of beam analysis.

During these tests, each optical system is exposed to approximately 30 minutes. When studying the optical configuration of the beam had on the lens diameter 9.6 mm, which leads to a power density of from 2.8 kW/cm2at 2 kW.

Fig. 4 compares the change in the position of the focal point of the beam focused by the lens system of ZnS or of fused silica (S). For each curve, the first point corresponds to the position registered in the first beam analysis performed at 200 watts. With that power, the focal displacement due to the effect of thermal lensing, is negligible. We can assume that the measured position corresponds to the position in which immediately is the focal point of the beam after turning on the laser. The focal displacement is then measured relative to this provision. Consequently, this first point on the curves corresponds to the offset from zero of the focal point.

Fig. 5 shows that the longitudinal offset from the focal point for the system of molten�of silicon (Si) more what is the offset for the system with ZnS. The use of ZnS allows, thus, to reduce the amplitude of displacement of the focus point in the radiation optical system with strong power.

The effect of changing the thickness at the edges of the collimating lens was also studied. To this end we compared the amplitude of displacement of the focal point obtained from the ZnS lens system comprising collimating lens with a thickness E on the edges equal to 2 mm, or system that includes a collimating lens with a thickness E on the edges equal to 7 mm.

Fig. 5 compares the change in the position of the focal point of the beam focused by both systems in accordance with the method described above.

It is seen that longitudinal displacement of the focal point more, since the collimating lens thinner.

The combination of optical devices according to the present invention, can guarantee the duration of the method of laser cutting, in particular in the case of a laser cutting method using a solid state laser, in particular a fiber laser, by controlling the amplitude of the focus shift problems and damage to optical systems.

1. Focusing the laser beam head for laser cutting metal parts containing collimating lens (13) and a focusing lens (14), characterized in that:
- collimating lens (13) and focusing lens (4) is made of ZnS and has a thickness on the edges of at least 5 mm, and
- deflecting mirror (15) located between the collimating lens (13) and a focusing lens (14) in the path of the laser beam in said focusing head so that the laser beam has an angle (α) is the reflection from 40° to 50° from the deflecting mirror (15).

2. Focusing the laser beam head according to claim 1, characterized in that the collimating lens (13) and focusing lens (14) have the edges of the thickness, the value of which is between 5 mm to 10 mm, preferably 6 mm to 8 mm.

3. Focusing the laser beam head according to one of the preceding claims, characterized in that the collimating lens (13) and focusing lens (14) have a diameter, the value of which is from 35 mm to 55 mm.

4. Focusing the laser beam head according to claim 1, characterized in that the deflecting mirror (15) is made of silicon.

5. Installation for laser cutting of metal parts, comprising:
- solid-state laser device (SL) that emits a laser beam with a wavelength of 1.06 μm to 1.10 μm and a power of 0.1 kW to 25 kW,
- focusing the laser beam head for laser cutting metal parts according to one of claims.1-4, and
- transmitting fiber (FDC) connecting the solid-state laser device (SL) and a focusing head so as to bring the laser beam emitted from the solid-state laser device (SL), to a focusing head.

6. Install pop. 5, characterized in that the solid-state laser device (SL) is a plan view of a fiber laser, preferably a fiber laser doped with ytterbium.

7. Apparatus according to claim 5 or 6, characterized in that the solid-state laser device (SL) emits a laser beam with power ranging from 1 kW to 5 kW, CW, quasi-CW or pulsed mode, preferably in continuous mode.

8. Apparatus according to claim 5, characterized in that the transmitting fiber (FDC) has a diameter that does not exceed 150 μm, preferably 50 μm or 100 μm.

9. Apparatus according to claim 5, characterized in that the solid-state laser device (SL) emits a laser beam with a beam quality parameter (BPP) from 1.6 mm·mrad to 4 mm·mrad.

10. Apparatus according to claim 5, characterized in that the transmitting fiber (FDC) has a diameter of 50 μm and CDF from 1.6 mm·mrad to 2.2 mm·mrad, and the collimating lens has a focal length from 70 mm to 120 mm.

11. Apparatus according to claim 5, characterized in that the transmitting fiber (FDC) has a diameter of 100 μm or BPP from 2.6 mm·mrad to 4 mm·mrad, and the collimating lens has a focal length of 130 mm to 180 mm.

12. Apparatus according to claim 5, characterized in that the focusing lens has a focal length of 200 mm to 450 mm.

13. Method of laser cutting metal parts (10) which uses laser cutting metal�coy details according to one of claims. 5-12.



 

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EFFECT: high image contrast on the entire field of vision in a wide temperature range.

2 cl, 3 dwg, 3 tbl

FIELD: physics.

SUBSTANCE: lens according to both versions comprises four components, the second and fourth of which are fixed and have two fixed positions each. The first component is in the form of a positive meniscus whose concave surface faces the image plane, the third component is in the form of a positive meniscus whose convex surface faces the image plane, and the fourth component is positive and is in the form of two menisci whose convex surfaces face each other. In the first version, the second component includes a biconcave lens and a negative meniscus facing the biconcave lens with its convex surface. In the second version, the second component is in the form of two negative menisci facing each other with their concave surfaces. Relationships given in the claim are satisfied.

EFFECT: wider angular field, high aperture ratio in narrow field of view mode, providing quasi-equal aperture ratio values when changing the field of view, short relative length of the lens while providing high image quality.

5 cl, 12 dwg, 2 tbl

FIELD: physics, navigation.

SUBSTANCE: invention relates to the field of detection of infrared radiation of low altitude objects. A complex of equipment for air observation includes installation of a thermal imaging camera on a fastened balloon with the possibility of circular rotation of the camera around the vertical axis and variation of the angle of camera inclination to the vertical axis due to its placement on the horizontal shaft. Two thermal imaging cameras are placed on two fastened balloons. Cameras represent infrared mirror-lens telescopes having mosaic photodetecting devices, comprising a large number of pixels 1024×1024, read in series with the help of a CCD matrix. Balloons are filled with hydrogen produced directly in place, by means of water electrolysis.

EFFECT: invention is aimed at increased sensitivity of detection of low-altitude objects.

1 dwg

FIELD: physics.

SUBSTANCE: optical system for a thermal imaging device comprises, arranged in series on the beam path, an input lens which constructs a real intermediate image and comprises a negative and a positive meniscus, and a projection lens mounted in front of a photodetector and comprising, arranged in series on the beam path, a first meniscus, a second negative meniscus whose convex side faces the photodetector, a third positive meniscus whose convex side faces the object space, and a fourth positive meniscus whose convex side faces the photodetector. In the input lens, the negative meniscus lies first on the beam path and after the positive meniscus there is an additional negative meniscus whose convex side faces the real intermediate image. In the projection lens, the first meniscus is positive and its convex side faces the photodetector, and the fourth meniscus is located between the third meniscus of the projection lens and the photodetector.

EFFECT: high resolution of the optical system of the thermal imaging device while maintaining compactness thereof.

1 tbl, 1 dwg

FIELD: physics.

SUBSTANCE: objective lens has two components separated by an aperture diaphragm. The first component consists of a positive meniscus whose concave side faces the image space, and a glued meniscus whose concave side faces the image space, between which there is a negative meniscus whose concave side faces the image space. The glued meniscus whose concave side faces the image space is positive and consists of a biconvex and a biconcave lens. The second component comprises a biconcave lens and two biconvex lenses. The biconcave lens and the first biconvex lens are glued. A negative meniscus whose concave side faces the object space is further placed behind the second biconvex lens.

EFFECT: larger angular and linear field of view and obtaining diffraction image quality at the centre and on the field of view.

2 cl, 1 dwg, 1 app

FIELD: physics.

SUBSTANCE: first component is fixed and is in form of a positive meniscus whose convex surface faces the object space, the second movable component is in form of a biconcave lens, the third component is fixed and the first two menisci therein are positive and face each other with their convex surfaces, and third component is a plane-concave lens, whose flat surface faces the image plane, the fourth fixed positive component includes three menisci whose concave surfaces face the image plane, the first and third menisci of which are positive and the second meniscus is negative. The second surface of the lens of the first component, the first surface of the lens of the second component and the concave surface of the first positive meniscus of the fourth component are aspherical.

EFFECT: high transmission factor of the optical system and manufacturability while maintaining a high aperture ratio, differential magnification and image quality.

8 dwg, 1 tbl

FIELD: nanotechnology.

SUBSTANCE: invention relates to the field of optical nanotechnologies, optical instrument-making, rocket, space, laser optics, quantum and optical nanoelectronics, useful for display, television and medical technology. The optical coating is a thin layer (100 nm or less) coating based on carbon nanotubes with the magnitude of inhomogeneities on the nanometer level. For application of carbon nanotubes on the substrate a slot CO2-laser is used with the laser beam controlled in power. The optical element consists of the coating based on carbon nanotubes and a hygroscopic substrate. The substrates of KBr, NaCl, KCl are used for providing functioning of this optical coating up to the middle infrared region of the spectrum. The coating is able to function in the infrared regions of the spectrum.

EFFECT: increased moisture resistance of the coating.

3 dwg

FIELD: chemistry.

SUBSTANCE: invention relates to a method of forming a transparent doped layer containing zinc oxide on a polymer substrate for optoelectronic devices and a transparent doped layer. The method includes contacting a polymer substrate with at least one precursor containing a dopant and zinc, and exposing to ultraviolet light during chemical vapour deposition to decompose at least one precursor and deposit a layer on the polymer substrate. The polymer substrate is selected from a group consisting of fluoropolymer resins, polyesters, polyacrylates, polyamides, polyimides and polycarbonates. The contacting step is carried out at pressure approximately equal to atmospheric pressure.

EFFECT: providing a chemical vapour deposition method for depositing doped zinc oxide films on polymer substrates for use in optoelectronics.

12 cl, 1 tbl, 8 dwg, 2 ex

FIELD: chemistry.

SUBSTANCE: group of inventions relates to a polimerisation-able photochromic isocyanate composition, containing a photochromic compound, to a photochromic mesh optical material and to a method of its obtaining. The polimerisation-able photochromic isocyanate composition includes. wt.p.: an organic photochromic compound 1-15; a polymerisation catalyst 0.01-5, polymerisable compounds 100. The polymerisable compounds contain, wt.p.: diisocyanates and/or oligoisocyanurateisocyanates 60-100, monoisocyanates 0-40. The catalyst is used in an amount of 0.01-5 wt.p. per 100 wt.p. of the polymerisable compounds. Also described is the photochromic mesh optical material - the product, obtained by thermal hardening of the polymerisation-able composition, described above, at least, on one surface of a sheet of a transparent substrate, made of polymethylmethacrylate, polycarbonate, polyethyleneterephthalate, cellulose derivatives, polyvinyl alcohol, polyvinylchloride, polyvinylidenchloride, polyethers, polyurethanes. Also described is a method of obtaining the photochromic mesh optical material.

EFFECT: obtaining the polymerisation-able photochromic isocyanate composition with high adhesion ability and product based on it with high optical properties, such as transparency, colourlessness, or colouration, and long-term exploitation.

13 cl, 2 tbl, 25 ex

FIELD: physics, optics.

SUBSTANCE: invention can be used in optical systems of UV, visible and IR optical, optoelectronic and laser devices. A flat-concave lens is made of a plastically deformed piece part, wherein an integral flat surface is perpendicular to an axis of symmetry of the piece part and formed from an apex of the piece part at x0<H, wherein H is the thickness of the piece part. An output surface of the lens has a profile providing measuring the thickness hy=h0×n0/ny, wherein h0 is the lens thickness in the centre, n0 is an ordinary beam refraction index, while ny is an extraordinary beam refraction index at a distance Y from the lens centre. The piece part is made by the plastic deformation of a parallel-sided plate of a crystal Z-section by the central annular bend. The lens surface is formed by removing an excessive layer of the material from the piece part.

EFFECT: producing the leucosapphire lens forming the flat wavefront of extraordinary beams and transparent within 25,000-2,000 cm-1 for a parallel beam of light perpendicular to the input surface.

2 cl, 1 dwg

FIELD: chemistry.

SUBSTANCE: invention relates to improved method of obtaining workpieces from silver halides and their solid solutions for fibrous infrared lightguides, which includes application on silver halide crystal-core of crystalline shell of crystalline silver halide with refraction index lower than in crystal-core, and thermal processing. Shell on crystal-core is applied by ion-exchange diffusion in ion-exchange source, as the latter taken is finely disperse silver halide powder with coarseness 1-20 mcm, diffusion is carried out at temperature, close to melting temperature of crystal-core in atmosphere of mixture of vapours of halides, included into composition of crystal material and powder, taken in equal ratio under pressure 0.2-0.5 atm.

EFFECT: method makes it possible to reduce optic loss of lightduides, operating in infrared spectrum range.

2 ex

FIELD: chemistry.

SUBSTANCE: multilayered coating contains three successive layers with an even thickness: a lower mirror metal radio-reflecting skin-layer of pure aluminium, an intermediate protective thermoregulatory dielectric layer of zirconium dioxide and an upper protective wear-resistant highly strong diamond-like carbon layer.

EFFECT: provision of the operation in extreme conditions of open space due to the application of a thin substrate-envelope from a polymer composite material.

3 cl, 1 dwg

FIELD: process engineering.

SUBSTANCE: invention relates to a monocrystal with a garnet-type structure to be used in optical communication and laser processing devices. This monocrystal is described by general formula (Tb3-xScx)(Sc2-yAly)Al3O12-z, where 0<x<0.1; 0≤y≤0.2; 0≤z≤0/.3.

EFFECT: translucent monocrystal that can inhibit cracking at cutting.

5 cl, 3 dwg, 1 tbl, 5 ex

Immersion liquid // 2535065

FIELD: chemistry.

SUBSTANCE: invention relates to an immersion liquid which can be used in optical instrument-making for investigating optical parameters of inorganic materials and optical components, including large, irregularly shaped articles. The immersion liquid for optical investigation contains 97-99 wt % meta-bis(meta-phenoxyphenoxy)benzene and 1-3 wt % 2-naphthol. To reduce viscosity and surface tension, the immersion liquid may further contain 0.1-3 wt % dibutyl sebacate per 100 wt % of said composition.

EFFECT: disclosed immersion liquid is nontoxic, has a good refraction index nD>1,6 and high adhesion to inorganic optical materials, which enables to deposit on the entire surface of the investigated substrate or part thereof a thin immersion layer and use thereof for effective quality control of large optical articles without immersion in a cell with an immersion liquid.

2 cl, 2 dwg, 2 tbl, 2 ex

FIELD: physics, optics.

SUBSTANCE: invention relates to visible light absorbers, particularly novel azo compound monomers, particularly suitable for use in materials for implantable ophthalmic lens materials. The ophthalmic device material includes an azo compound, a device forming acrylic monomer and a cross-linking agent. The ophthalmic device is made from the ophthalmic device material and is in the form of intraocular lenses, contact lenses, keratoprostheses and corneal inlays or rings.

EFFECT: azo compounds are suitable for use as monomers which absorb part of the visible light spectrum (about 380-495 nm).

17 cl, 6 dwg, 3 tbl

FIELD: physics.

SUBSTANCE: free form ophthalmic lens comprises a first optical zone portion comprising multiple voxels of polymerised crosslinkable material containing a photoabsorptive component. The optical zone portion comprises a first area having a first refraction index and a second area having a second refraction index; and a second portion comprising a layered volume of crosslinkable material polymerised beyond the gel point of the crosslinkable material.

EFFECT: obtaining ophthalmic lenses with a free form surface and areas with different refraction indices, which enable to correct vision by changing the focal distance.

18 cl, 19 dwg

FIELD: physics.

SUBSTANCE: film is placed in a liquid medium which is transparent for laser radiation, having a refraction index of not less than 1.5 and pulses are focused by an optical system with a lens with a numerical aperture of not less than 0.33 or the film is placed behind a plate made of material which is transparent for laser radiation, having a refraction index of not less than 1.5 and pulses are focused by an optical system with a lens with a numerical aperture of not less than 0.5. The film is placed at a distance from the lens which is greater than the focal distance of said system during paraxial approximation. Said film is placed in a focal constriction with overlapping of the film and a hole is formed in said film. The energy of the ultra-short laser radiation pulse is set based on a condition of providing energy density of the laser radiation which is higher than the breakdown threshold of the material of the film in the region of the focal constriction.

EFFECT: device enables to form a hole with a diameter of up to 5 mcm in a film with thickness of up to 100 mcm using a single ultra-short laser radiation pulse.

7 cl, 5 dwg

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