JP2000351089A - Optical assembly for laser beam generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the breakage or damage of a protective window by providing a means to cool a focal lens to protect the protective window from the damage caused by the gas pressure, and to unify the pressure around the protective window. SOLUTION: A unifying means preferably comprises at least one hole, desirably a plurality of holes provided in a protective window assembly or a protective window. A protective window 219 with a drilled hole is positioned in an inner cylindrical chamber of a lens mount so as to form a cavity between the protective window 219 and an operation end part of a lens 218. This protective window 219 completely fills the operation end part of the cylindrical chamber to prevent a sputter from a work from being brought into contact with the focal lens 218. The protective window 219 is drilled to allow the gas into the cavity generated by a spacer, i.e., an inner flange 217, and the pressure is equalized before and behind the window 219 in the space of the cavity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention is filed on Oct. 6, 1995, US patent application Ser. No. 08 / 540,56.
U.S. patent application Ser. No. 08 / 668,384, filed on Jun. 21, 1997, U.S. Pat.
No. 8/880663 is a CIP application.

The present invention relates to or in conjunction with a focus lens assembly in a laser beam generator in which a protective window is provided to protect the focus lens and in particular to protect the coating on the lens from contamination. A protective window assembly for use integrally with the protective window assembly. The protective window is located in a single housing containing the focus lens or in a separate housing operatively secured to the assembly containing the focus lens.

[0003]

BACKGROUND OF THE INVENTION Lasers are a universal and important mechanism for cutting, marking, welding and surfacing materials such as metals, including stainless steel. The term “Laser” is a term for Light Ampl.
ifation by Stimulated E
It is an acronym for “mission of Radiation”. The most common stimulating media are carbon dioxide gas and neodymium yttrium aluminum garnet (Nd: Y
AG).

The maximum laser productivity depends on the output power, the laser beam quality and the ease of operation of the device for the desired purpose. One of the most common reasons for poor laser performance is contamination of the laser equipment, especially of the focusing lens. Sources of laser contamination include impurities in the laser gas or nozzle pressurization gas, leakage of the vacuum system, backflow of the vacuum pump oil into the laser cavity, sputtering of metal atoms from the electrodes (sp.
utering), fingerprints, vacuum grease, the presence of contaminants in the area where the optical system is housed, and the like.

[0005] Many laser systems use several types of nozzles in front of the final focus lens. The nozzle carries pressurized gas to the workpiece and serves to prevent debris from being sprayed onto the focus lens. Focal lens contamination is one of the main reasons for poor laser performance and downtime of laser work. However, the nozzle system is not perfect,
Some debris, vapors or back spatter often reaches the laser.

[0006] More recent laser systems employ protective windows to protect the focusing lens from contamination. This protective window is positioned in front of the focusing lens, and both optics are contained within the lens assembly. This system is not preferred because the protection window requires modification or disassembly of the lens assembly to replace or renew a protection window that can change the focal length of the laser beam. Such systems are often not practical because the lens holder is not designed to house the protective window.

[0007] Lasers are widely used as a means of cutting steel, stainless steel, aluminum, titanium, plastic, wood and other materials. Lasers are also used for welding. In many cutting applications, a gas known as an assist gas as a high pressure gas is used to assist in this cutting process. High pressure oxygen has been used to cut carbon or mild steel. Nitrogen assist gas is commonly used to cut stainless steel, and argon and helium are used to cut titanium. Gases used to cut materials other than mild steel tend to be used at higher pressures than oxygen used to cut mild steel. The assist gas performs various functions depending on the material to be cut.

[0008] Oxygen reacts with ions in the mild steel to release energy, which causes the steel to melt more quickly than a single laser provided at the same power level. The reaction of oxygen with such ions effectively doubles the energy output of the laser. An inert assist gas is used for cutting stainless steel. This is because undesired black adherent lumps remain on the surface and form rough edges on the thick pieces by oxygen cutting. By eliminating this oxygen-ion reaction, even higher power will be used to cut stainless steel.

[0009]

SUMMARY OF THE INVENTION CO2 (carbon dioxide)
The high viscosity of the stainless steel melted by laser cutting results in the adhesion of grime or dross to the bottom edge of the material. To alleviate this problem, a very high gas pressure assist gas is blown through the cut in order to get rid of this dross. The assist gas would also be used to blow off spatter generated by the cutting process from the laser focus lens and cool the focus lens. The assist gas is introduced to the cutting surface via a laser cutting head and is conveyed to the cutting surface by the same nozzle through which the laser beam passes. When the assist gas is introduced into the cutting head, the assist gas resides in the same room in which the focusing lens is located, so that the assist gas exerts pressure on the lens.

[0010] The smoke or smoke and steel particles resulting from the CO2 laser cutting and welding process are known as "spatter." This spatter can damage the laser focus lens and the anti-reflective coating attached to the lens to enhance the transfer of energy through the lens. Sputters tend to be small particles which adhere to the focusing lens and the anti-reflective coating on the lens. Sputters can scorch and damage these lenses and coatings. As such spatter damage and contamination forms on the lens, the energy transmitted by the focal lens is reduced until insufficient energy is transferred to the lens focus to continue effective cutting. . At this time, the lens must be replaced. CO2 laser focus lenses are very expensive. If the lens is not replaced, the lens may begin to absorb an excessive amount of energy, which may cause overheating and melt the lens. If the lenses melt, the expensive internal optics components of the laser are exposed to contamination and they will be destroyed.

Many laser cutting devices that use assist gas also use this assist gas to cool the focus lens. Recently, some CO2 laser system users have used a protective window in front of the focus laser to protect the focus laser from spatter. These protective windows are usually added by the user, and today the means for using protective windows are from any CO2 laser system manufacturer using high pressure gas for cutting. Not provided. However, users of such systems having sufficient clearance in the focus lens mount or mount have placed protective windows in front of the lens with limited success. Many users have laser systems in which the lens mount cannot accommodate the protective window without removing the focusing lens. If the lens is moved, the focal point of the laser beam changes. Consequently, if the system is not provided with focus adjustment applicability to accommodate the movement of the focus lens or if there is not enough clearance in the lens mount for another optical system For example, in order to mount a protective window, certain improvements or additions must be made to accommodate the protective window in the lens mount. For this reason, many users of laser-based welding and cutting systems are unable to use protective windows.

[0012] NaCl and KCl are the most practical materials for use as protective windows. Unfortunately, protective windows formed of these materials are damaged by pressure. Thus, the use of the protective window is well confined to the CO2 laser welding system, no assist gas is used, and the pressure on the protective window is not a factor. Furthermore, if the lenses in the system are intended to be cooled by the assist gas, a protective window located in front of the lens prevents the assist gas from cooling the lenses. Increasingly, high laser power is being used in the industry, which results in the lens receiving higher energy, which creates a heat rise, and the thermal effects on such focus lenses are of concern. ing.

Since most cutting lasers, or cutting lasers, operate at high pressure, at least for some time, there is a need to invent means that can handle the pressure so that the use of protective windows can be practical in cutting applications. It is. Simply creating space for a protective window in the lens mounting system does not address pressure. Furthermore, the insertion of the protective window prevents the assist gas from cooling the focusing lens.

As mentioned above, the standard protective window used for CO2 lasers is NaCl or KCl.
It is a crystal material formed from. These window materials are economical and will transmit 90% or more of the energy available in CO2 laser systems without using expensive non-reflective coatings. However, these materials cannot withstand the high pressures generated by the assist gas during the cutting operation.

As mentioned above, there is no CO2 laser cutting system containing a protective window in the market formed by the major laser manufacturers. The use of a method or apparatus in which the protective window can operate in a pressure neutral environment and is protected from the pressure of the assist gas depends on the configuration and other design features of the industrial laser for which it is desired to use the protective window. Limited by various features. Some laser systems employ a lens mounting configuration that has insufficient airspace to mount the means for using a protective window in the presence of high pressure assist gas, while other laser systems use A proprietary design is employed that has features such as impractical autofocus that alter or add to the manufacturer's lens mounting or lens mount design. Industrial Laser Review (Industrial Laser Review)
According to a recent study published by w), there are more than thousands of industrial laser welding and cutting systems in this field, and more than 1200 new cutting systems are sold each year. . Because the laser systems described above do not provide a means for using a protective window, and in such systems the cost of replacing a damaged focus lens is significant, such laser systems contain a high pressure assist gas and have a focus lens. It would be a significant advantage to provide such a method and apparatus that protects the focus lens from spatter by using a protective window that can properly cool the lens.

[0016] Devices for holding a protective window in front of a laser focus lens are known. U.S. Pat. No. 5,312,397 to Cosmescu and U.S. Pat. No. 45 to Diakuzno
No. 92353 discloses an apparatus for protecting the laser optics used in a surgical process from blood and body fluids that would harm the surgical procedure in procedures such as laser laparoscopy. . These devices are used in systems that are quite different from industrial CO2 laser cutting systems. The devices disclosed by Cosmechu and Diakzuno are used with low power lasers. The device disclosed by Diakzuno relates to fiber optic systems such as Nd: YAG and argon which are not high power industrial lasers such as CO2 lasers.

More importantly, blood and bodily fluids that contaminate the optics during a surgical procedure are significantly different from materials such as molten metal or plastic that affect the optics in a CO2 laser cutting system.
In the latter case, they are mostly solid, which can cause permanent damage to the lens by sticking to the lens, burning the lens, or leaving marks on the lens, whereas in the former case, it is mostly water. It can be wiped away. An economical protective window that is practical for use with CO2 cutting lasers such as NaCl and KCl would not be surgically usable due to its water solubility. On the other hand, in surgical prescriptions, expensive water-insoluble crystals such as sapphire are used and reused as protective windows. The use of sapphire in a cutting laser means that sapphire can be NaCl or KCl
Would be impractical because it is much more expensive. In fact, sapphire is as expensive as zinc selenide (ZnSe) from which the focusing lens is made. Sacrificing a sapphire protective window for a ZnSe lens in an industrial laser detracts from economic sense. Although the sapphire protective window can be cleaned and reused in a surgical setting, it will be easily broken in an industrial cutting or welding setting. In addition, sapphire is not a useful laser transmitter at the 10.6 micron wavelength at which the CO2 laser operates.

Another significant difference between a high power CO2 laser cutting system and a low power surgical laser system in the use of the previously disclosed devices is the stainless steel in the CO2 laser cutting system. The use of a high pressure assist gas of 30 psi or more to cut steel and other objects. The high pressure assist gas used in the CO2 laser cutting system has not been proposed by cosmetic shoes or diakzuno. The use of inexpensive material as a protective window in a CO2 laser cutting system may negate the assist gas pressure to provide support for the protective window, such as using an optical mounting device or the method and apparatus of the present invention. Requests use of equipment. Furthermore, if the protective window blocks the assist gas as a means of cooling the focus lens, another means must be used so that the assist gas can cool the lens as well as the protective window.

Finally, while the known devices are intended to embody systems and devices designed to accommodate protective windows, in accordance with one aspect of the present invention, they are coupled to new devices. Retrofit protection windows to existing systems
ting).

[0020]

SUMMARY OF THE INVENTION The present invention relates to a protective window assembly in a laser beam generator where a focusing lens is protected by a protective window contained within the protective window assembly and with or with the focusing lens assembly. And using the protective window assembly in one piece therewith. The protective window assembly is removably attached to or integral with a focus lens assembly that includes the focus lens. When the focus lens assembly and the protective window assembly are mounted together, the focus lens is economically and effectively protected from contamination.
Replacement or renewal of the protective window can often be performed without changing or disassembling the focus lens assembly.

According to one aspect of the present invention, there is provided a protective window assembly comprising a protective window assembly which is releasably securable to a laser beam generator or a laser beam generator. A protective window assembly is provided which is integral with the focus lens assembly for use with the device. The protective window assembly comprises: (a) a housing with a recess for securing the protective window therein; and (b) securing means for securing the housing to a focus lens assembly including a focus lens. ,have.

According to another aspect of the present invention, a housing for securing the protective window is releasably attachable to the focus lens assembly. In another embodiment of the present invention, the protective window assembly is integral with the focus lens assembly.

According to a preferred aspect of the present invention, the protective window assembly housing allows gas to pass through the housing to equalize the pressure around the protective window, thus preventing breakage or damage of the protective window. Preventing.

Further in accordance with a preferred aspect of the present invention, the protective window assembly or drilled window (see below) has a sufficient number of holes, these holes providing sufficient sized gas passages. A functional and protective window is operatively positioned to allow sufficient flow of assist gas within the system used internally to cool the focus lens.

According to another embodiment of the present invention, the protective window places the protective window directly against the flat surface of the focusing lens, so that the flat surface of the barrier or a large part of the window is the lens. It is in contact with most of the flat surface and thus the additional support provided by the focusing lens sufficiently enhances the strength of the protective barrier or window, thereby preventing the protective window from breaking under high pressure. According to another preferred embodiment of the present invention,
A sufficient number of holes are drilled into the protective window, high pressure assist gas passes through the window to equalize the pressure around the focus lens and cool the lens, and (i) small spacers Is located on the working side of the lens between the lens and the protective window to form a hollow depression, or (ii) a flange is located in the lens mount integral with the lens mount or lens mount. It provides the same function as the spacer. In both embodiments, the protective window or the protective window and the spacer (or flange) can be housed in a similar recess of the existing system, in which the lens (i) makes the existing recess longer and deeper. Thus, (ii) by replacing a thin focal lens having a focal length similar to that used in the lenses used so far, (iii) like a spring or holding screw securing the lens (Iv) reducing the size of one or more of the elements by moving the focus lens to a position that has sufficient points in the system to adjust the focus so that the focus of the laser beam is not altered, or a longer focal length. Is moved to the position where the lens of the alternative is used, or (v) by combining the above (i) to (iv), It is of being positioned by forming between.

The following figures show specific examples of embodiments of the present invention, in which like numerals indicate like parts.
It is not intended to limit the invention as described in the claims of the application.

The present invention relates to a protective window assembly, and also to protect the focus lens from spatter while simultaneously protecting the protective window against high gas pressures and allowing the focus lens to cool properly. Are disclosed with respect to using. The protective window assembly used by the present invention protects the protective window from damage and at the same time protects the focus lens from contamination, and can achieve such protection economically and effectively. Things. The protective window assembly can be used alone, and can be detachably or even incorporated as an integral part of the focus lens assembly that is plugged into the laser beam generator.

A high-pressure gas (eg, nitrogen gas) is used as an assist gas to assist the laser operation. The assist gas reinforces the cutting operation and, as described above, provides an environment that is superior to the atmosphere of the factory to blow off spatter from the focusing lens. Under certain circumstances, such as when cutting stainless steel, the pressure of the assist gas can be very high (eg, 150-300 psig). The high pressure gas can break or destroy windows used to protect the lens.

High power laser cutting systems often use an assist gas to cool the focal lens of the system. When a protective window is used to protect the focus lens from spatter, the protective window prevents assist gas from reaching the lens. This leads to overheating of the lens, which in turn causes distortion of the lens and even melting of the lens. According to a preferred embodiment of the present invention, the high gas pressure around the protective window is in a neutral state, providing a means for cooling the lens with the aid of an assist gas, and further providing a protective window to protect the lens from sputter contamination. An example of use is provided.

The economic and practical resilience of NaCl, KCl and other materials for use as a barrier to protect the focus lens in industrial lasers makes CO2 laser focus lenses such as zinc selenide (ZnSe) Lower than the elasticity of the material used. If ZnSe is used as a protective window, a relatively thin window must be used. This is to make this rather expensive material material economically feasible for protective window applications. However, such thin windows are very easily broken or destroyed by the high pressure assist gas. Focusing lenses used in CO2 laser systems designed for applications such as cutting stainless steel must withstand assist gas pressures in the 300 psig range. Such high pressure assist gases are typically used only for high power lasers (250 watts or more) used for cutting. High pressure assist gas is not found in medical CO2 lasers, and the optics in such medical systems need not withstand high pressures. In such high pressure applications, if no method or apparatus for handling high pressure is employed, KC
Thin windows made of many barrier materials such as 1 and NaCl and more expensive materials such as ZnSe will break. In many systems using high pressure assist gas, the assist gas is used as a means to cool the focus lens.

The most high power, high power CO2 laser systems for cutting on the market today are not structured to accept devices that have windows to protect the focus lens from spatter and other damage. The dimensions and shapes of the cutting head and lens mount used in many of these systems have little or no space to improve so that a protective barrier window can be added. Furthermore, many systems do not have the flexibility to substantially change the focusing parameters incorporated into these systems, assuming that the position of the focus lens will not be changed. for that reason,
Since it is almost always necessary to accommodate the mounting system for the protective or barrier window in the limited space of the elements in the laser system including either the focusing lens or the mounting device for the focusing lens. is there. Furthermore, such accommodation should almost always be done without changing the position of the focusing lens. It means that changing the position of the focusing lens changes the focus of the laser where the cutting operation takes place, and many existing laser cutting systems allow focusing to compensate for such changes in focus position. Because it does not have a sufficient focal range. When sufficient space exists and the shape of the cutting head and lens mount is not unduly limited, the methods and apparatus described above can be employed.

However, in many types of cutting heads and lens mounts, the external shape of the hardware having the lens mount is changed or the external shape is added, and the position of the lens is changed. Or changing the head is not possible due to the functional and geometric constraints imposed by the laser cutting system in which these heads and mounts are used. These geometric and system constraints have not been overcome with the prior art. That is because the prior art has been directed to low pressure laser systems such as those used surgically.

The present invention and particularly the embodiments described below,
The pressure provided by the assist gas used in the laser system is directed to a protective window assembly that is neutralized by means that does not substantially alter the external dimensions of the focus lens mounting hardware. This can be achieved by pressing the flat surface of the protective window against the flat surface of the focusing lens in those systems where plano-convex lenses are used, or by placing pressure on either side of the protective window, as in the preferred embodiment. Achieved by using a protective window drilled with holes and in sufficient size, number and position to allow the assist gas to flow into the recess between the focus lens and the protective window to be equal. I have. This furthermore means that, in another preferred embodiment of the invention, the protective window is provided on the outside of the lens mount by inserting a window holder with gas passage means inside the lens mount by means as shown in FIGS. This can be achieved by being mounted in a geometrical geometry. In accordance with yet another preferred embodiment of the present invention, a protective window assembly with gas passing means or a window with drilling is provided, wherein assist gas is introduced into the system where the protective window is used to cool the focusing lens. It has a sufficient number of holes of sufficient dimensions positioned to provide sufficient gas flow.

The use of gas passing means allows the assist gas to continue to cool the lens and the protective window, but in order to cool the lens, the heat passing from the lens is carried away so that the assist gas carries away the heat from the lens. It is necessary that the means circulate the assist gas sufficiently. With higher power lasers, gas passing means suitable for equalizing the pressure on both sides of the protective window so as not to damage the protective window are inadequate for cooling the lens. Therefore, when arranging a plurality of holes in the protective window or the protective window assembly holding the protective window when manufacturing the gas passage means, the number and size of the holes are sufficiently large, and the lens and the protective window are provided. The holes need to be properly positioned to carry the heat away from the rear surface and thereby provide a circulation rate of the assist gas to help cool these optics. Thus, although a smaller number of holes would be appropriate to serve as a gas passage means for pressure equalization,
Larger diameter holes or a greater number of holes will be required to cool the optics device. Further, when the gas passage means are holes drilled into the optical system, it is desirable to drill the holes closer to the center to allow for cooling. For example,
Suitably one hole is located in the optics to allow sufficient pressure to pass through the window to achieve pressure equilibrium, but more holes are needed to cool the optics. Become. Similarly, when the gas passage means is a hole formed by drilling into a protective window or an assembly on which a focusing lens is mounted, of course, the gas passage means comprising a hole formed by drilling into an optical system is formed to such an extent that the gas passage means is formed. Similar considerations apply, except that it may not be possible to drill holes close to the center of the optics, but the gas may be directed towards the center of the lens. In yet another preferred embodiment of the invention, it is required to cool the lens, and the holes are drilled into both the protective window and the focusing lens or the element of the assembly in which the protective window is mounted. Should be understood.

In a preferred embodiment of the present invention using a drilled window, the recess between the focusing lens and the protective window creates a thickness between the lens and the protective window, for example, about 1 mm to 2 mm. Possess and 1
It is formed by inserting a small cylindrical spacer having a width of 2 mm to 2 mm.

In another preferred embodiment of the present invention using a drilled window, the spacer is used as a means for forming a recess between the lens and the protective window, the active side (cutting side) of the lens. Has been replaced by a small flange located on the inside diameter of the cylindrical part of the lens mount in which it sits. The protective window sits on the opposite side of the flange or spacer. The use of a flange instead of a spacer means that the means for forming a recess between the lens and the protective window to make the pressure on the protective window neutral and the focusing lens cannot be changed. This has the advantage of being a means for forcibly positioning the lens. Such a flange has the advantage of forcing the lens in these systems where the lens is not seated on its upper surface (usually convex).

In all of the embodiments of the present invention, sufficient space is provided for mounting the protective window and for accommodating the spacers or flanges, the spacers or flanges comprising (a) a lens mounting set. The dimensions of the various elements of the volume, such as, but not limited to, (i) the lens, (ii) the spring, (iii) the retaining screw, (iv) the many segments of the lens mount that can be shortened ( (B)
By removing non-essential elements such as spacers and wave springs, and (c) the working end (cutting end) by a small distance that does not exceed the focusing capability of the system or can be corrected with a lens having a longer focal length It is used to form a recess by moving the lens backwards from section (1).

[0038]

FIG. 1 shows a focusing lens in a Mitsubishi CO2 industrial laser system.
lens mount (lens mou) similar to the type used by Mitsubishi to mount the lens
FIG. 3 is a diagram showing a cross section of type (nt). This lens mount has a hollow cylindrical assembly 201. The assembly 201 has openings at both ends 202 and 203. The focus lens 204 is seated on the flanges 205a and 205b of this opening, and the holding screw 206 and the spacer 2
07 and an O-ring 208 fixed in place.
The convex surface of the lens is the laser (upper) of the assembly 201
It is arranged so as to face the end 202. A hole 2 in which assist gas is drilled around the periphery of the working end 203 of the cylindrical chamber in the assembly
09. The distance between the flange 205a, 205b on which the lens rests and the top of the assembly is represented by D = X.

FIG. 2 shows an exploded view of the internal components of FIG. 1, which contain retaining screws 206, spacers 207, and O-rings, which can be released by use of a spanner wrench. Gasket 208 and FIG.
And a focusing lens 204 mounted on the flange indicated by flanges 205a, 205b.

FIG. 3 shows a sectional view of a lens mount according to a preferred embodiment of the present invention, which can be manufactured as an alternative to a lens mount of the type shown in FIG. In this preferred embodiment, the flanges 210a, 210b are protected windows.
w) Flange 20 in FIG.
It is perforated deeper than 5a and 205b. When this preferred embodiment of the invention is manufactured as a replacement for a lens mount of the type shown in FIG. 1, the invention has the same external form and dimensions, and the position and size of the focusing lens It has not been modified by improvements or differences between the internal form of the invention and the internal form of the lens mount of the style of FIG. A protective window 211 positioned into the inner cylindrical chamber of the lens mount is pressed against the flat surface of the plano-convex lens 212 as a means to provide sufficient support for the protective window 211 and the inner cylindrical recess or chamber of the assembly. The lens does not break when exposed to the high pressure of the assist gas introduced through hole 209 around the periphery of the working end 213. It will be appreciated that a drilled protective window 211 is used in the preferred embodiment for assist gas cooling of the focus lens. This protective window 211 completely fills the working end of the cylindrical chamber 213, so that the splash from the work, that is, the spatter,
2 is prevented from coming into contact. Room 21 required to house protective window 211
Incremental depth of the interior chamber extending the point at which the flange is positioned towards the working end of the third
depth) is represented by D = Y. Y is also the thickness of the protective window. The total depth of the chamber 213 with the protective window at this position is represented by D = X + Y.
Here, D is the total distance, X is the one shown in FIG. 1, and the increment interval Y is the lens mount having the same external form as the lens mount shown in FIG. Is required to accommodate the protection window 211.

FIG. 4 is an exploded view of the internal components shown in FIG. 3, showing a retaining screw 214 of the type released by use of a spanner wrench, a spacer 215, an O-ring or gasket 216, and a seat on the protective window 211. Focusing lens 212 is shown. As shown in FIG. 3, the protective window 211 has flanges 210a, 210
b.

FIG. 5 is a sectional view of a lens mount showing another preferred embodiment of the present invention which can be used as an alternative to a lens mount of the type shown in FIG. Flange 22
Oa, 220b are perforated to a sufficient depth to receive the protective window 219 and the spacer or inner flange 217. The preferred embodiment of the present invention shown in FIG. 5 can be formed to have the same external form and dimensions as a lens mount of the type shown in FIG. If used, it can be formed to be identical to a lens mount of the type shown in FIG. A protective window 219 with a drilled hole is positioned within the interior cylindrical chamber of the lens mount to form a cavity between the protective window 219 and the working (flat) end of the lens 218. The protective window 219 completely fills the working end of the cylindrical chamber, so that spatter from the work is prevented from coming into contact with the focusing lens 218. The drilling of the protective window 219 allows the gas to assist in passing into the cavities created by the spacers or internal flanges 217 so that pressure can be created in front of and behind the window 219 in the space within the cavities. It is possible that both are equal. This puts the window 219 in a pressure neutral state. The cavity is formed by a spacer or inner flange 217 located between the working end of the lens and the window. In a preferred embodiment of the present invention, a sufficient number and size of holes are drilled into appropriate locations in the protective window,
Assist gas can be used as a means to cool the focus lens and the window.

Assuming that the thickness of the spacer, that is, the inner flange 217 is A, D = A. According to this example of the preferred embodiment, the overall depth D of the chamber is the same as in the other preferred embodiment shown in FIG. 3 and is represented by X + Y, so that D = X + Y. In this preferred embodiment, the spacing provided by the additional elements not used in the embodiment shown in FIG.
The distance between the flanges 217 separating the first and the second 19 is D = A.
Represented by Spacer or internal flange 217
Is provided by making the lens thinner by A, where A is the flange 2
The same dimensions as required to accommodate 17 intervals. However, all or part of the spacing required to accommodate this spacer and protective window can be provided by making the protective window thinner by dimension A or by making both the protective window and the lens thinner. Will be understood. In addition, if the focal length of the lens is changed or if the system has sufficient focus capability, by moving the lens toward the top of the cavities 221 in the lens mount and by using the retaining screw 2
It is understood that by making one or more elements thinner, such as 22 or spacer 223, additional space is formed to accommodate the spacer or protective window. Further, when a spacer or internal flange is added to separate the protective window and the lens, the lens will take on a form other than a plano-convex lens. This is because the flat sides are no longer required to support the protective window so that it is not destroyed by pressure.

In this embodiment of the present invention, it is not necessary for the protective window to contact the lens to provide a means of preventing the protective window from being damaged by the pressure applied by the assist gas, which is not necessary. This embodiment makes it practical to use with focus lenses that do not have a flat surface, such as meniscus lenses and defractive lenses that will support the window. Further, it will be appreciated that the spacer may be omitted from between the lens 218 and the drilled protective window 219 if the working end surface of the lens is sufficiently concave to form a depression where the assist pressure may be equal. Will be. Also, in a preferred embodiment of the present invention, a sufficient number and size of holes are drilled into the protective window so that the assist gas can be used as a means for cooling the focus lens and the window. Will be understood.

FIG. 6 shows a working end retaining screw 225 optional for the internal element in the preferred embodiment of the present invention shown in FIG.
FIG. This internal element includes a retaining screw 222, a spacer 223, an O-ring 224,
Focusing lens 218 and spacer or inner flange 21
7 and a holding window 219 formed by drilling. It will be appreciated that if an internal flange is used in the location of the spacer, it will be integral with the wall of the cylindrical internal chamber of the assembly shown in FIG. 5 and will not be a separate element. Such an integral flange 217 may be used with the lower working end retaining screw 225. An advantage of the inner flange 217 integral with the inner wall of the assembly chamber is that such a flange positively positions the lens at the focal point of the laser beam and prevents inadvertent minor changes in the focal point. The use of the working end retaining screw is similar to that of the flange 2 shown in FIG.
It can be seen that 20a, 220b has been removed and that the inner diameter of the cylindrical chamber of the assembly will be threaded (not shown) with a female thread (not shown) that will thread into the male thread of retaining screw 225. Another advantage of using the optional working end retaining screw 225 in conjunction with the inner flange 217 is that the protective window can be moved independently of the focusing lens by simply moving the retaining screw from the working end of the assembly. And at the same time the lens is held undisturbed, thus preventing the lens or the coating on the lens from being damaged by mishandling when the protective window is replaced.
The use of a working end retaining screw would require the use of means (not shown) that allow the assist gas to pass through or over the retaining screw, such as a hole or slot.

FIG. 7 is a cross-sectional view of a lens mount of a type typically used by Trumpf to mount a focusing lens on a CO2 laser head. The assembly that makes up this lens mount is composed of two main elements 226, 2 screwed together and pressing a lens 228 and a spring 229 therebetween.
27. The larger main element 226 has flanges or shoulders 230a, 230b on which the convex side of the lens sits. Furthermore, this element 226 has internal threads 231a, 231b, which are the external threads 23 of another main element 227.
2a and 232b. The lens mount assembly includes holes 233a, 233b, 233c that direct the assist gas toward the lens to cool the lens and repel spatter. A spring 229 is located below the focusing lens 228 to allow thermal expansion of the lens and to prevent damage from accidental over-tightening. These springs and lenses are held in place by flanges or shoulders 235a, 235b formed by the top of the lower portion 227 of the lens mount, and flanges 230a, 230b on which the convex surfaces of the lenses sit. I have. The form of this style of lens mount is complex and the lens mount is tightly enclosed within the cylinder or tube 233 in the cutting head 234, thus adding or modifying its external form to the lens mount assembly. This is not possible without redesigning the entire cutting head or making any modifications to the lens mount assembly. Here, these design changes or modifications would allow the assist gas to flow into the recess behind the protective window without blocking the laser and maintaining the same focal length, but to achieve them Would be impossible or very complicated and expensive.

FIG. 8 shows a cross-sectional view of another preferred embodiment of the present invention. In this figure, the lens mounting assembly has an external configuration similar to the type of lens mount shown in FIG. In this preferred embodiment of the present invention, the same as in FIG. 7 so as not to change the focus of the laser beam when the present invention is used as a lens mount instead of a lens mount of the type shown in FIG. Can be manufactured so that the focus lens is maintained in the position of Spacer or flange 23
9 is positioned in the assembly between the focus lens 238 and the drilled protective window 240 to form a recess 241 between the focus lens 238 and the drilled protective window 240 and pressurized therein. Assist gas can flow in. Protective window 240 is cylindrical chamber 2
The work end 43 is completely filled to prevent spatter from the work from scattering to contact the focus lens 238. Drilling of the protective window 240 allows the assist gas to flow into the recess 241 formed by the spacer or inner flange 239, thereby providing a pressure within the recess 241 at both the front and rear of the window 240. Are equalized, thus creating a pressure neutral environment in the window 240. The recess 241 is formed by a spacer or inner flange 239 located between the working end of the lens and the window.
In a preferred embodiment of the present invention, a sufficient number and size of holes are drilled into the protective window at appropriate locations,
It will be appreciated that the gas can thus be used as a means for cooling the focus lens and the window.

It is understood that this embodiment of the present invention may be used as a replacement for an existing lens mount of the type shown in FIG. Here, the space occupied by the spacer or flange 239 and the protective window 240 (denoted by D = Y) shortens the working end of the lens mount by a distance equal to "y".

In this embodiment of the present invention, there is no need to contact the protective window with the lens to provide a means of preventing the window from being damaged by the pressure applied by the assist gas. The examples are suitable for use with focusing lenses that do not have a flat surface that would support a window, such as meniscus lenses and defractive lenses. Also, if the working end surface of the lens has enough recesses to form a recess so that the assist gas can be equalized, a spacer or flange 239 may be formed between the lens 238 and the drilled protective window 240. It is understood that it could be deleted from time.

FIG. 9 is an exploded view of the internal elements of the preferred embodiment of the present invention shown in FIG.
, A spacer or flange 239, a drilled protective window 240, and a spring 242.

FIG. 10 is an exploded perspective view of another preferred embodiment of the present invention, in which a drilled protective window 246 has an external configuration similar to lens mounts manufactured by Laser Mechanism and others. Is mounted on a drawer type lens mount assembly 244 that can be manufactured. Such lens mounts are intended to use the present invention as an alternative to such types of lens mounts, with the Cincinnati Tripit & Laser Cut brand (Cincinnati, Str.)
ippit and Laser Cut brand
s), including those used in several laser systems. In the illustrated preferred embodiment of the present invention, a drilled protective window 246 is positioned in front of the focusing lens 249 so that the protective window comprises a cylindrical recess 252 in which the focusing lens 249 is mounted. The entire hole is blocked. If this preferred embodiment of the present invention is used in place of a drawer-type lens mount assembly manufactured by Laser Mechanism Corporation and other companies, the lens mount will have substantially similar dimensions to the lens mount. Have to slide into the holes of existing laser system cutting heads (not shown) having a shape and shape, and require non-viable cutting head modifications to accommodate larger or differently shaped lens mounts It will be. In the illustrated preferred embodiment of the present invention, the gap required to accommodate the protective window 246 when the present invention is used as an alternative lens mount in an existing laser system, is increased by the following means. Can be formed without changing the external form. That is,
(I) using a thinner focus lens 249 than is typically used in OEM designs; (ii) moving the lens back 1-2 mm from the workpiece by shortening the holding screw 250 by 1-2 mm. , (I
ii) Move the spacer 248 from the front of the working end of the assembly to a position below the focus lens 249 between the protection window 246 and the lens 249, or place the spacer 248 between the protection window 246 and the lens 249. Replace with a smaller spacer or remove the spacer in some cases (see below). If the focal length is moved, the focal length will be changed, and if the system does not have enough focus adjustment to accommodate the focal length change, housing a focal length with a longer focal length will be used. It must be understood that it must be done.

The lens 249 and the protection window 24 formed with a drill are formed in the recess through which the pressurized assist gas can flow.
6, a spacer 248 is disposed between the focusing lens 249 and the drilled protective window 246. Drilling of the protective window 246 allows the assist gas to flow into the recess formed by the spacer 248 or optional internal flange (not shown), which equalizes the pressure both in front and behind the window 246. And this
The window 246 creates a pressure neutral or neutral environment. Lens mount cylindrical recess 252
The working end has a flange 253 on which a protective window is seated. In another form of this embodiment of the present invention, a working end retaining screw 251 can be used in place of the flange 253 to handle the focus lens to prevent accidental damage to the focus lens due to mishandling. The protection window can be removed without any problem.

In this embodiment of the present invention, it is not necessary for the protective window to contact the lens to provide a means of preventing the protective window from being destroyed by the pressure provided by the assist gas.
This makes this embodiment practical for use with focus lenses that do not have a flat surface, such as meniscus lenses or defractive lenses that will support the window. However, in another embodiment (not shown) of the present invention, the protective window is arranged to contact the flat surface of the plano-convex lens to provide support for the protective window, as shown in FIG. It can be understood that it gets. Furthermore, if the working end surface of the lens is sufficiently recessed to form a recess that allows the assist gas pressure to be equalized, a spacer or flange 248 may be inserted between the lens 249 and the drilled protective window 246. It can be understood that can be deleted.

FIG. 11 illustrates a Bistronic (Bystronic) for focusing a lens of a laser cutting system similar to the concept of the tubular lens mount shown in FIG.
FIG. 3 shows a cross section of a tubular lens mount of the type used by S. Onic) and others. However, while in FIG. 7 the tube comprises two main elements screwed together, the tube of FIG. 11 is a single internally threaded tube 254, in which an external thread is provided. A holding screw 255 is inserted to hold the focus lens 256 in place within the tube 254. The tube can be of various lengths to accommodate various focal lengths and cutting head configurations, and if the lens assembly is placed in the tube, loosen the retaining screw 255 to remove the optics by removing the retaining screw 255. It will be appreciated that the use of a spanner wrench with a long handle is required. The focus lens 256 is mounted inside the tube 254, and the lens 256 is mounted on the tube flange or shoulder 257.
a, 257b. This focusing lens 256
Is positioned in a predetermined position by an O-ring 259 mounted in a groove or recess in the spring 258 between the spring 258 and the lower (working end) surface of the lens 256, and an assembly constituted by the spring 258 and the like. This assembly includes a retaining screw 2 having an external thread threaded into tube 254.
55 secures into the tube. Assemblies 255, 25
The space occupied by 6,258,259 is represented by D = X.

FIG. 12 is a cross-sectional view of another preferred embodiment of the present invention, in which a lens mounting system uses the present invention instead of a lens mount of the type shown in FIG. It can be formed to have an external form similar to a lens mount of the type shown. When the preferred embodiment of the present invention is used as an alternative lens mount for an existing system, the focus lens 260 is positioned at the same position as the focus lens 256 in the lens mount shown in FIG. 11 so as not to change the focus of the laser beam. A spacer is provided between the focal lens 260 and the drilled protective window 262 in the assembly to form a recess 263 between the lens 260 and the drilled protective window 262 through which the pressurized assist gas can flow. Alternatively, a flange 261 is provided. The protective window 262 completely fills the working end of the cylindrical chamber 264 so that spatter from the workpiece is prevented from coming into contact with the focusing lens 260. Drilling of the protective window 262 allows the assist gas to flow into a recess 263 formed by the spacer or flange 261, which recess 263 is both in front of and behind the window 262 in the space within the recess 263. Pressure at
It is pressure neutral for window 262. This indentation is provided by a spacer or flange 2 located between the working end of lens 260 and window 262.
61.

This embodiment of the present invention can be used as a replacement for an existing lens mount of the type shown in FIG. 11, and for the lens mount shown in FIG. 12, a spacer or flange 261, a protective window 262, a lens 260, O-ring 265, spring 266, and retaining screw 2
67 are housed in a similar distance as indicated by D = X which houses the lens 256, O-ring 259, spring 258, and holding screw 255 in a lens mount of the type shown in FIG. The additional spacing occupied by the protective window 262 and spacers or flanges 261 used in this preferred embodiment of the present invention, as indicated by D = Y, is the OEM of lens mounts of the type shown in FIG. It can be used by using a smaller spring 266 and retaining screw 267 than used in the version. Lens 26
The assembly consisting of the spacer 261, the protective window 262, the O-ring 265, and the spring 266 forms a shoulder or flange 268 a, 268 b forming part of the tube 269 containing the assembly in the cutting head 270.
The lens 260 is held at a predetermined position by a holding screw 267 that presses the lens 260.

In this embodiment of the present invention, it is not necessary for the protective window to contact the lens to provide a means to prevent the protective window from being destroyed by the pressure provided by the assist gas.
This makes this embodiment practical for use with focus lenses that do not have a flat surface, such as meniscus lenses or defractive lenses that will support the window. However, in another embodiment (not shown) of the present invention, the protective window is arranged to contact the flat surface of the plano-convex lens to provide support for the protective window, as shown in FIG. It can be understood that it gets. Furthermore, if the working end surface of the lens is sufficiently recessed to form a recess that allows the assist gas pressure to be equalized, a spacer or flange 248 may be inserted between the lens 249 and the drilled protective window 246. It can be understood that can be deleted. Further, in a preferred embodiment of the present invention, a sufficient number and size of holes can be drilled into appropriate locations within the protective window so that the assist gas is used as a means for cooling the focus lens and the window. It is understood that.

A lens mounting system as shown in FIG. 11 is a commercially available laser system that can be used in a power range of about 1500 watts to at least about 3000 watts when used. High power lasers generate more energy and can be absorbed by the focusing lens, which generates heat when the lens absorbs energy. Excessive heat can deform or damage the lens, resulting in a range of defects ranging from distorting the laser beam spot size or focus to severe damage that melts the lens. FIG. 11 in which the preferred embodiment of the present invention is used as shown in FIGS.
In a 3000 watt laser equipped with a cutting head similar to that shown in FIG. 6, six 1/16 inch diameter holes 301 arranged around the protective window 302 as shown in FIGS. Are suitable as gas passage means for equalizing the pressure in front and behind the window. However, if the assist gas is a means for cooling the lens, when such a hole geometry is used, the heat generated by the beam will cause the focus lens 2 located behind the protective window 262 to be positioned.
Will distort 60. When a larger diameter hole 303 is added closer to the center of window 302, as shown in FIG. 16B, the laser can operate at a higher high power rate but is not yet at full power. However, as shown in FIG. 16C, the addition of a large diameter hole 304 to the window 302 as the second row allows the laser to operate at substantially full power without lens damage. I can do it. When these large holes are located close to the periphery of the window and the small holes are located close to the center, or when equally sized holes are placed in the proper position, multiple holes are created in the window. It will be appreciated that in combination, similar results may be obtained as would be obtained with the proper placement of a plurality of holes in the assembly in which the lens or window is mounted.

Referring to FIGS. 14 and 15, the lens mount is a Mazak lens mount 409.
To the focus lens 408
Is a flat spring 40 like a wave spring
6 against the flange 411. The adapter has the form of two stacked retaining screws 402, 405, one retaining screw 402 is a male screw 402
A and is screwed into a female screw (not shown) of the other holding screw 405. These two elements 402, 40
5 is the original equipment manufacturer of the laser system.
It replaces the lens mount retaining screw supplied by the tmanufacturer (OEM). A protective window 404 is inserted through the working end of the lens mount and a larger retaining screw 405 on flange 412 (see FIG. 15) located at the laser end of the retaining screw.
It is attached inside. The assist gas passes through the hole 405A of the larger holding screw 405,
The pressure of the assist gas is leveled in the recess formed between the lens 408 and the protective window 404. This depression is formed by the wave spring 406 and the spacer 407. According to another embodiment of the present invention, these holes 405A are provided in the outer casing of the lens mount 409 or, depending on the form of the assembly, between the protective window mount and the assembly in which the lens is mounted. It will be appreciated that other elements such as can be arranged radially. If properly operated, this protection window 404 can be removed and a replacement can be installed without disturbing the focus lens 408, which is required when the protection window 404 is changed. Limit the amount of focus performed.

The protective window 404 has an inner retaining screw 402 that overlaps a larger outer retaining screw 405.
Is held at a predetermined position. Protective window 4
An O-ring 403 is arranged between the holding screw 04 and the holding screw. The O-ring allows the window to expand when the window is heated and also cushions the optics when pressure is applied. Outer holding screw 4
Reference numeral 05 is tightened with a predetermined pressure to hold the focus lens at a predetermined position. Thereafter, other elements are assembled.

A hole 405A in the lens mount allows the assist gas pressure to bypass the protection window 404. The wave spring 406 must be positioned as shown so as to level the assist gas in front of and behind the protective window, thereby allowing an opening through which the assist gas passes through hole 405A. I have. In the presently preferred embodiment, a sufficient number and size of holes are provided in the protective window or in the lens or window mounting assembly 402,
It will be appreciated that drilling into the elements 405, 409, or into both the window and such elements, the assist gas can be used as a means to cool the focusing lens and window.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a portion of a component for mounting a lens of the type typically used on some CO2 laser systems for mounting a focus lens, which houses a protective window and also protects the protective window from damage. FIG. 3 shows a situation where the area is restricted to expand the device to accommodate high pressures in the system to prevent it.

FIG. 2 is a partial exploded view of an element relating to a lens mounting of the type shown in FIG.

FIG. 3 shows a lens installation of the type shown in FIG.
FIG. 3 is a cross-sectional view of a preferred embodiment of the present invention, including means for employing a protective window.

FIG. 4 is a partial exploded view of an element relating to a lens mounting of the type shown in FIG. 3;

FIG. 5 is a cross-sectional view of another preferred embodiment of the present invention showing a lens mount of the type shown in FIG. 4 with another means of employing a protective window.

FIG. 6 is a three-dimensional exploded view of the internal components and optional lower retaining screw for the lens mounting shown in FIG.

FIG. 7 is a cross-sectional view of the elements associated with a lens mount of the type commonly used in certain CO2 laser systems.

FIG. 8 shows a lens installation of the type shown in FIG.
FIG. 6 is a cross-sectional view of another embodiment of the present invention including means for employing a protective window.

9 is a three-dimensional exploded view of internal element parts related to the lens attachment shown in FIG.

FIG. 10 is a three-dimensional exploded view of a preferred embodiment of the present invention in which means for housing a protective window are used.

FIG. 11 is a cross-sectional view of components for a type of lens mounting commonly used in a CO2 laser system for mounting a focusing lens.

FIG. 12 is a cross-sectional view of another embodiment of the present invention comprising means for employing a protective window for mounting a lens of the type shown in FIG.

FIG. 13 is a three-dimensional exploded view of internal element parts relating to lens attachment shown in FIG.

FIG. 14 is a three-dimensional exploded view showing another embodiment of the lens mounting assembly according to the present invention.

FIG. 15 is a cross-sectional view of the lens mounting assembly shown in FIG. 14 including a protective window.

FIG. 16 is a plan view showing an embodiment of a protection window used in the present invention, and A, B, and C show preferred specific examples, respectively.

[Explanation of symbols]

209: hole 210a, 210b: flange 21
1: protection window 212: plano-convex lens 213: internal cylindrical recess 21
4: Protective screw 215: Spacer 216: O-ring 21
7: Spacer 218: Focus lens 219: Protective window 220a, 220b: Flange 221: Cavity
222: Protective screw 223: Spacer 224: O-ring 225:
Holding screw 238: Focus lens 239: Flange 240:
Holding window 241: recess 242: spring 243:
Cylindrical chamber 244: lens mount assembly or lens mounting assembly 246: protective window 248: spacer 24
9: Focus lens 250, 251: Holding screw 252: Cylindrical recess 25
3: Flange 260: Focus lens 261: Spacer 26
2: Protective window 263: recess 264: cylindrical chamber 26
5: O-ring 266: Spring 267: Holding screw 268a, 268
b: Flange 269: Pipe 270: Cutting head 301:
Hole 302: Protection window 303, 304: Hole 40
2, 402A: Screw 404: Protective window 405: Holding screw 40
5A: Male screw 406: Flat spring 408: Focus lens 409: Mazak lens mount 411, 412:
Flange

Claims (10)

[Claims] 1. An optical assembly for a laser beam generator, comprising: (a) a housing for securing a protective window;
A protective window assembly having a protective window secured into the housing at a location in the path of the laser beam between the focal point of the laser beam and the focusing lens;
(C) a recess between the protective window and the focus lens; and (d) means for cooling the focus lens and leveling the pressure around the protective window to protect the protective window from damage caused by gas pressure. An optical assembly for a laser beam generator. 2. The means for cooling the focus lens and leveling the pressure around the protective window comprises gas passing means to allow gas to pass through or around the protective window assembly. An optical system assembly for a laser beam generator according to claim 1. 3. The method of claim 1, wherein the means for cooling the focus lens and leveling the pressure around the protective window comprises gas passing means for allowing gas to pass through or around the protective window. An optical assembly for the laser beam generator according to the above. 4. The gas passage means is a hole in the protective window assembly or the protective window, the gas passage means being of a size sufficient to level the gas pressure and cool the focus lens and at least in a predetermined position. The optical system assembly for a laser beam generator according to claim 2, comprising one hole. 5. The gas passage means comprises a protective window assembly or window having a plurality of apertures of sufficient size and location to allow gas pressure to be leveled and to cool the focus lens. 3. An optical system assembly for a laser beam generator according to item 2. 6. A method of protecting a focus lens of a laser beam generator, comprising: arranging a protection window assembly having a protection window near the focus lens, leveling pressure around the protection window and focusing the focus lens. Passing a gas through or around a protective window assembly to cool the focus lens of a laser beam generator. 7. The assist gas is directed through at least one aperture having a size and location sufficient to level the pressure in the protective window assembly or the protective window and to cool the focus lens. The method for protecting a focal lens of a laser beam generator according to claim 6, comprising: 8. The method according to claim 6, further comprising: directing an assist gas around the protection window assembly or the protection window. 9. The method of claim 1, wherein the protective window and the lens assembly each have a flat surface, and wherein the method further includes the steps of: contacting the flat surfaces of the protective window and the lens assembly with the flat surfaces. The method for protecting a focus lens of a laser beam generator according to claim 6, wherein 10. The method of claim 1, wherein the protective window and the focus lens are separated by a recess, and the method further comprises adjusting a size of the recess, one or more of a lens assembly including the focus lens. Reducing the thickness of the element, reducing the size of the element holding the lens assembly, adjusting the position or increasing the central depression of one or more elements of the lens assembly, and 7. The method according to claim 6, further comprising: holding a means for accommodating at least the protection window in the three-dimensional object.