JP6783374B2 - Material handling using a laser with a variable beam shape - Google Patents

Description

(Related application)
The present application is the benefit of US Provisional Patent Application No. 62 / 362,824 filed on July 15, 2016 and US Patent Application No. 15 / 261,096 filed on September 9, 2016, and to it. Priority is claimed and the entire disclosure of each of these is incorporated herein by reference.

In various embodiments, the present invention relates to the processing of materials (eg, welding or cutting) utilizing high power laser devices with formable beam and / or variable beam polarization.

High power lasers are used in many cutting, etching, annealing, welding, drilling, and soldering applications. As in any material handling operation, efficiency can be an important limiting factor in terms of cost and time. That is, the lower the efficiency, the higher the cost and / or the slower the operation of the laser deployed to process a given material. The brightness and polarization of the laser beam can affect efficiency, and different materials (copper, aluminum, steel, etc.) respond differently to beam polarization as they are processed. In addition, the thickness of these materials can also affect their polarization response. That is, the cutting or welding properties can vary with beam polarization, depending on the material and its thickness. For example, a linearly polarized processed beam can be absorbed differently depending on the polarization orientation of the beam with respect to the cut surface. For this reason, laser-processing systems sometimes utilize circular or randomly polarized laser outputs to avoid directional dependent polarization responses. The approach avoids the inefficient consequences of unfavorable polarization orientation, but also excludes the benefits of favorable orientation.

In addition, high power laser systems often have a laser emitter and a workpiece to process the laser light from the fiber, from which the laser light is coupled into an optical fiber (or simply "fiber"). Includes an optical system that focuses on the piece. Optical systems are typically engineered to produce the highest quality laser beams, or, in other words, beams with the lowest beam parameter product (BPP). BPP is the product of the divergence angle (half angle) of the laser beam and the radius of the beam at its narrowest point (ie, beam waist, minimum spot size). BPP quantifies the quality of the laser beam and the degree to which it can be focused on small spots and is typically expressed in millimeter-milliradian (mm-mrad) units. (The BPP values disclosed herein are in mm-mrad, unless otherwise indicated.) Gaussian beams are the minimum possible BPP determined by the wavelength of the laser beam divided by pi. Has. The BPP of the actual beam at the same wavelength, the ratio for an ideal Gaussian beam is shown as M ^2, which is a wavelength-independent measurement of beam quality.

Techniques such as WBC have been successful in producing laser-based systems for a variety of applications, but material handling challenges remain. For example, a laser with a beam shape optimized for cutting a particular material to a particular thickness may not be suitable for different materials, materials with different thicknesses, and materials with variable thicknesses. The welding process presents similar challenges. Moreover, due to the limited spatial range of conventional highly focused laser beams, the welding process typically requires relative motion between the laser beam and the part being welded, such as Exercise may require complex and expensive robots, mobile gantry, and / or other equipment. Techniques have been developed that utilize multiple laser systems with movable beams (see, eg, US Pat. No. 9,335,551, the entire disclosure of which is incorporated herein by reference). The use of multiple laser systems is often very expensive. Therefore, there is a need for individual laser systems that are possible for a wider variety of material processes.

In many laser processing applications, the desired beam spot size, divergence, and beam quality can vary, for example, depending on the type of treatment and / or the type of material being treated. In order to make such changes to the BPP and / or shape of the laser beam, the output optics or fiber optics often have to be replaced and / or rematched with other components, which is time consuming , And an expensive process, which can also lead to inadvertent damage to the fragile optical components of the laser system.

U.S. Pat. No. 9,335,551

Therefore, to improve the efficiency of laser processing operations, also take advantage of variable responses to beam polarization and / or other beam properties (eg, BPP and / or beam shape) that characterize different materials and material thicknesses. There is a need for improved systems and techniques.

According to embodiments of the present invention, a laser system with a formable power beam is utilized to optimize and simplify material processing tasks such as cutting and welding metal materials. For example, according to an embodiment of the invention, the output beam shape of the laser system will be more (eg, from a Gaussian focused spot beam) as the thickness of the component and / or the angle of the component presented to the laser beam fluctuates. It is modified (to a circular beam with a large area). In another exemplary embodiment, the output beam of the laser system is modified during the welding process (eg, spot welding, butt welding, or lap welding) between the laser beam and the workpiece being processed. Form large area welds without any (or minimal) relative motion.

Embodiments of the invention also modify and optimize the polarization and / or other properties of the beam (eg, BPP, shape) during the process, for example, the beam path varies throughout the process, or the properties of the material. Alternatively, it provides a system and technique that maintains the optimum properties of the beam as the thickness changes.

Embodiments of the present invention may modify the polarization of the beam as the thickness of the workpiece changes and / or for workpieces of different thickness. For example, the roundness of the beam's polarization (ie, any number of ellipses with varying dimensions and curvatures, ranging from linear to elliptical to circular, can be between perfect linear and perfect circle. (Possible), but as the thickness of the workpiece increases, the beam can be modified to be more circular (eg, linear to elliptical, less circular elliptical to more circular ellipse). From oval to circular, etc.). (In various embodiments, the roundness of polarized light is inversely proportional to the eccentricity of elliptical polarized light, eccentricity 0 represents circularly polarized light, and eccentricity 1 represents linearly polarized light.) In various embodiments, the beam of the beam. The polarization state is modified, at least in part, through the use of a Babenet-Soleil compensator, which allows for continuously variable polarization of any degree of eccentricity. Embodiments of the invention can also vary the polarization of the beam from linear to radial, for example, to bring the focus of the beam to a smaller spot size.

Embodiments of the invention typically allow the surface of the workpiece to be physically modified, as opposed to optical techniques (eg, reflectance measurements) that simply probe the surface with light. , And / or are utilized to process the workpiece so that features are formed on or within the surface. Illustrative processes according to embodiments of the present invention include cutting, welding, drilling, and soldering. Various embodiments of the invention also include the workpiece at one or more spots or along a one-dimensional processing path, rather than filling all or substantially all of the workpiece surface with radiation from the laser beam. To process.

Embodiments of the invention use optical elements capable of forming a laser beam and modifying the beam quality (particularly BPP) and / or the shape of the beam to achieve the desired spatial beam profile. More specifically, changes in the optical geometry of the optical element due to lateral or longitudinal movement or displacement of its position with respect to the optic axis of the laser beam cause variations in shape and / or BPP. It may be used. In embodiments of the invention, the optics are located in a beam path and entail a switchable state that produces different beam deflections or diffractions depending on the position. The use of optics according to embodiments of the present invention allows variations in shape and / or BPP regardless of the shape, quality, wavelength, bandwidth, and number of beams corresponding to the input laser beam. Output beams with controllably variable shapes and / or BPPs may be used to process workpieces in applications such as welding, cutting, drilling and the like. As used herein, a change in the "shape" of a laser beam refers to a modification of the shape and geometric range of the beam (eg, at the point where the beam intersects the surface). Shape changes can occur with changes in beam size, beam angular intensity distribution, and BPP, but mere changes in beam BPP are not necessarily due to changes in laser beam shape and vice versa. Not enough (eg, depict two beams with different shapes but with the same BPP, see FIG. 21).

One advantage of variable geometry and / or BPP is improved laser application performance for different types of processing techniques or different types of materials being processed. Embodiments of the present invention also include U.S. Patent Application No. 14 / 632,283 filed February 26, 2015, U.S. Patent Application No. 14 / 747,073 filed June 23, 2015, U.S. Patent Application No. 14 / 852,939 filed September 14, 2015, U.S. Patent Application No. 15 / 188,076 filed June 21, 2016, and April 5, 2017. Various for varying BPP and / or shape of the laser beam as described in U.S. Patent Application No. 15 / 479,745 filed (each disclosure is incorporated herein by reference in its entirety). You may use the technique of. In addition, the different beam intensity distributions induced by the optical elements (refractive optics) modify the beam quality and thus the BPP. Real-time dynamic changes in shape and / or BPP can be achieved by using translations of optical elements with different effective optical geometries within the beam path (eg, motor-driven translations).

Laser beam shaping is the process of redistributing the intensity (irradiance) and phase of a beam. Intensity distributions that define beam profiles such as gauss, vessel, annular, multimode, rectangular, top hat, oval or circular, and different intensity profiles may be important and necessary for specific laser material processing techniques. (As used herein, the "annular" beam is ring-shaped, i.e., has little or substantially no beam intensity in the central portion surrounded by the region of higher beam intensity. However, it is not necessarily circular, that is, the "annular" beam may be oval or otherwise quasi-annular.) In embodiments of the invention, the optical element works with the laser beam. Located within the delivery system, which delivers to and focuses the laser. The delivery system may be configured and / or packaged, for example, as at least part of a cutting head or welding head. Embodiments of the invention vary beam quality to allow controllably variable shapes and / or BPPs on workstations (and / or workstations placed on them). The variable shape and / or BPP module may include one or more optical elements, a motor driven translation stage, a collimating lens, and a focusing lens. Embodiments of the invention may feature any one or more of the plurality of types of refracting optics for optical elements used to vary shape and / or BPP.

Embodiments of the present invention vary beam quality by dynamically changing the position of one or more optical elements within the optical path of the laser beam. In one embodiment, the beam profile is adjusted by adjusting the beam pointing position on the optical element. The optics may have different geometries that depend on the desired beam profile and therefore BPP. One optical element according to an embodiment of the present invention has a flat surface and a flat top (ie, truncated) conical surface. Another optical element according to an embodiment of the present invention has a flat surface and a flat upper spherical surface. Yet another optical element according to an embodiment of the invention is a meniscus lens. The divergent rays from the beam delivery fiber are directed towards the optics and redistribute the beam intensity within the optics. Other optical elements according to embodiments of the present invention include paired positive and negative axicon lenses. In other embodiments, the optics include a pair of complementary phase plate lenses, one of which has a partially convex surface and one of which has a complementary partially concave curved surface. .. The edges of the optics may be rounded to suppress the diffraction effect. The advantage of dynamic variation of BPP with automated movement of optics has been applied, for example, to laser cutting applications on round or square cutting angles where BPP change during free-form cutting is required. May be good. Such advantages may also be applied to laser perforation applications where the ability to vary both BPP and focal length can be utilized. The automated closed-loop motor control of the optics according to embodiments of the present invention provides reliability and reproducibility performance, allowing precise control of the optical position, thereby providing accurate BPP variation.

As used herein, "optical elements" are lenses, mirrors, prisms that redirect, reflect, bend, or optically manipulate electromagnetic radiation in any other manner, unless otherwise indicated. , A grid, and one of the equivalents. As used herein, a beam emitter, emitter, or laser emitter, or laser, produces an electromagnetic beam, but may or may not be self-resonant, any electromagnetic beam-generating device, such as a semiconductor element. including. These also include fiber lasers, disc lasers, non-solid state lasers and the like. In general, each emitter includes a back-reflective surface, at least one optical gain medium, and a pre-reflective surface. The optical gain medium increases the gain of electromagnetic radiation, which can be visible light, infrared light, and / or ultraviolet light, but not limited to any particular portion of the electromagnetic spectrum. The emitter may include, or may consist essentially of, a plurality of beam emitters, such as diode bars, which are configured to emit the plurality of beams. The input beam received in the embodiments herein may be a single wavelength or multiwavelength beam that can be combined using various techniques known in the art. In addition, the reference to "laser," "laser emitter," or "beam emitter" herein is not limited to single diode lasers, but also diode bars, laser arrays, diode bar arrays, and single or arrays. Includes a vertical cavity surface emitting laser (VCSEL).

Embodiments of the present invention may also be used with wavelength beam coupling (WBC) systems that include multiple emitters, such as one or more diode bars, that are combined using dispersion elements to form a multi-wavelength beam. Good. Each emitter in the WBC system resonates individually and is stabilized through wavelength-specific feedback from an intersection reflected output coupler that is filtered by dispersion elements along the beam coupling dimension. The exemplary WBC system is incorporated herein by reference in its entirety, US Pat. No. 6,192,062, filed February 4, 2000, filed September 8, 1998. US Pat. Nos. 6,208,679 filed, US Pat. No. 8,670,180 filed on August 25, 2011, and US Pat. No. 8,559, filed March 7, 2011, It will be described in detail in No. 107. The multi-wavelength output beam of the WBC system may be utilized as an input beam in conjunction with embodiments of the present invention, for example for BPP, shape, and / or polarization control.

In one aspect, embodiments of the present invention feature a method of processing a workpiece. The processing path is defined by creating a relative motion between the laser output beam and the surface of the workpiece. The thickness of the workpiece along the direction parallel to the laser output beam varies along the processing path. The laser output beam physically modifies the surface of the workpiece along at least part of the processing path. During the relative motion between the laser output beam and the surface of the workpiece, the shape of the laser output beam is modified, at least in part, based on the thickness of the workpiece.

Embodiments of the present invention may include one or more of the following in any of the various combinations: The shape of the laser output beam may vary between the focused spot and the ring as the thickness of the workpiece increases. The shape of the laser output beam may vary between focused spots and diffuse spots (eg, spots having a diameter greater than the diameter of the focused spot) as the thickness of the workpiece increases. The diameter and / or BPP of the laser output beam may be increased as the thickness of the workpiece increases. The angle between the laser power beam and the surface of the workpiece is modified (eg, through the tilt of the incident laser power beam, the tilt of the workpiece, and / or the angled topology on the surface of the workpiece. Through), thereby varying the thickness of the workpiece along the direction parallel to the laser output beam. The thickness of the workpiece along the direction parallel to the laser output beam can vary, at least in part, due to changes in the angle between the laser output beam and the surface of the workpiece (eg, incident laser output). Through the tilt of the beam, the tilt of the workpiece, and / or through the angled topology on the surface of the workpiece). The shape of the laser output beam may be modified while maintaining a substantially constant angle between the laser output beam and the surface of the workpiece (eg, the laser output beam is tilted relative to the surface of the workpiece. It may not be necessary, or the topology of the workpiece surface may present a substantially constant angle with respect to the incident laser output beam). The thickness of the workpiece may be measured during the relative motion between the laser output beam and the surface of the workpiece. The shape of the laser output beam may be modified based on the composition of the workpiece. The laser output beam may consist of multiple wavelengths.

In another aspect, embodiments of the present invention feature a system for processing workpieces. This system has a beam emitter for emitting a laser output beam, a positioning device for changing the position of the laser output beam with respect to a workpiece, a means for modifying the shape of the laser output beam, and a positioning device. And coupled with shape-modifying means, (i) operate the beam emitter, causing the laser output beam to traverse the path across at least part of the workpiece and physically modify its surface, (ii) at least. Partly, it comprises, consists of, or consists of a controller for modifying the shape of the laser output beam based on the thickness of the workpiece along the path.

Embodiments of the present invention may include one or more of the following in any of the various combinations: The beam emitter may be located in or coupled to it (eg, via an optical fiber) from which the laser output beam is emitted, includes a processing head, then consists essentially of, consists of, and comprises. hand). The shape-modifying means include (i) one or more optical elements in the processing head and (ii) a second controller for modifying the position of at least one of the optical elements in the processing head. It consists of or may consist of it. The second controller may be separated from and separate from the controller, or the controller and the second controller may be part of a single control system. The controller may be configured to vary the output power of the beam emitter along the path. The controller may be configured to vary the shape of the laser output beam based on the composition of the workpiece. The system may include a database containing multiple records, each relating the laser output beam shape to the workpiece parameters. Workpiece parameters include, and / or workpiece composition, in essence, or may consist of it. The beam emitter receives a beam source that emits multiple discrete input beams, focusing optics for focusing the multiple input beams onto a dispersion element, and receives the focused beam and receives the received focused beam. A dispersion element for dispersion and a dispersed beam are received, a portion of the dispersed beam is transmitted through it as a laser output beam, and a second portion of the dispersed beam is reflected toward the dispersion element. Positioned, including, with a partially reflective output coupler, then essentially, or may consist of it. The laser output beam may consist of multiple wavelengths.

In yet another aspect, embodiments of the present invention feature a method of joining first and second workpieces at a processing point. The first and second workpieces overlap and / or are in close proximity to each other at the processing point. The laser output beam is focused and / or placed in close proximity to the processing point to melt at least one portion of the first or second workpiece, thereby squeezing the first and second workpieces. Join together. During the splicing, the shape of the laser output beam is varied without causing relative motion between the laser output beam and the first and second workpieces.

Embodiments of the present invention may include one or more of the following in any of the various combinations: The shape of the laser output beam may vary between the focused spot and the ring shape. The shape of the laser output beam may vary between focused spots and diffuse spots (eg, spots having a diameter greater than the diameter of the focused spot). The laser output beam may consist of multiple wavelengths.

In another aspect, embodiments of the present invention use a laser output beam capable of focusing on a minimum spot size and weld the first and second workpieces with a spatial range greater than the minimum spot size. It features a method of splicing. The laser output beam is focused and / or placed on the first and / or second workpieces and an adhesive (eg, brazing material, solder material, etc.) placed on or between the first and second workpieces. Or at least partial melting of the flux material) and / or at least partial melting. The shape of the laser power beam is varied, increasing the size of the weld or seam, without causing relative motion between the laser power beam and the first and second workpieces.

Embodiments of the present invention may include one or more of the following in any of the various combinations: The shape of the laser output beam may vary between the focused spot and the ring shape. The shape of the laser output beam may vary between focused spots and diffuse spots (eg, spots having a diameter greater than the diameter of the focused spot). The laser output beam may consist of multiple wavelengths.

In one aspect, embodiments of the present invention feature a system for processing workpieces. This system consists of a beam emitter, a positioning device for changing the beam position of the beam emitter with respect to the workpiece, a variable polarizing device for changing the polarization of the beam, and beam shaping for changing the shape of the beam. Combined with a vessel and a positioning device, a polarizing device, and a beam shaper, for its processing, a beam emitter is operated to allow the beam to traverse the path across at least part of the workpiece, at least partially. , Containing, and essentially consisting of, or consisting of a controller for varying the polarization and / or shape of the beam along the path, based on one or more properties of the workpiece.

Embodiments of the present invention may include one or more of the following in any of the various combinations: The controller may be configured to maintain linear polarization of the beam, having a polarization direction substantially parallel to the path as the beam traverses the path. The controller may be configured to vary the polarization eccentricity of the beam, at least in part, based on the thickness of the workpiece. The controller may be configured to vary the polarization of the beam between a linearly polarized state and a radially polarized state. The variable polarizing device includes, and consists essentially of, or may consist of a wave plate. The variable polarizing device includes, and may consist essentially of, a corrugated plate and a rotating element, the rotating element being operated by a controller. The wave plate comprises, and may consist essentially of, or consist of a half wave plate and / or a quarter wave plate. The beam may be linearly polarized. The controller may operate a rotating element to maintain a polarization direction parallel to the path. The variable polarizing device includes, and consists essentially of, a compensator plate, a fixed birefringence wedge located across the compensator plate, and a movable birefringence wedge located across the fixed birefringence wedge. Good. The variable polarizing device comprises, and essentially consists of, a compensator plate, a fixed birefringence wedge disposed across the compensator plate, a movable birefringence wedge disposed across the fixed birefringence wedge, and a translation element. Or may consist of it, the translation element is driven by the controller. The variable polarizing device includes, and may consist essentially of, or may consist of a radial polarizing converter.

The system may include a memory accessible to the controller for storing data corresponding to the path and a database for storing polarization data for a plurality of materials. The controller may be configured to query the database to obtain polarization data about the material of the workpiece and, at least in part, vary the polarization of the beam based on the polarization data. The path may include at least one directional change. The workpiece may have at least two portions having different thicknesses. The workpiece may have at least two parts that include, are essentially made up of, or consist of different materials. The beam emitter receives a beam source that emits multiple discrete input beams, focusing optics for focusing the multiple input beams onto a dispersion element, and receives the focused beam and receives the received focused beam. A dispersion element for dispersion and a dispersed beam is received, a part of the dispersed beam is transmitted through it as a beam of a beam emitter, and a second part of the dispersed beam is reflected toward the dispersion element. Positioned to allow, includes, and may consist essentially of, or consist of, a partially reflective output coupler. The beam of the beam emitter (eg, the output processing beam) may consist of multiple wavelengths.

The beam shaper includes a collimating lens for collimating the beam received from the beam emitter, a condensing lens for receiving the collimated beam and focusing the beam toward the workpiece, and a beam source and a collimating lens. Includes, and essentially consists of, an optical element for receiving and modifying the shape of the beam and a lens manipulation system for changing the position of the optical element within the path of the beam. It may consist of it. The controller may be configured to control the lens manipulation system and vary the shape of the beam. The optics include, and essentially a lens, which has (i) a first surface having a truncated conical shape and (ii) a second surface in a substantially flat plane opposite to the first surface. It may or may consist of it. The optics include, and essentially a lens, which has (i) a first surface having a truncated spherical shape and (ii) a second surface of a substantially flat surface opposite to the first surface. It may or may consist of it. The optics include, and may consist essentially of, or may consist of a meniscus lens. The lens manipulation system may be configured to position the optics laterally off-center in the path of the beam. The system may include a second optical element located between the focusing lens and the workpiece. The lens manipulation system may be configured to change the position of a second optical element in the path of the beam. The second optical element comprises a lens having (i) a first surface having a truncated conical shape and (ii) a second surface having a substantially flat surface opposite to the first surface. It consists of or may consist of it. The second optical element comprises a lens which has (i) a first surface having a truncated spherical shape and (ii) a second surface having a substantially flat surface opposite to the first surface. It consists of or may consist of it. The second optical element includes, and may consist essentially of, or may consist of a meniscus lens.

The beam shaper includes a collimating lens for collimating the beam received from the beam emitter, a condensing lens for receiving the collimated beam and focusing the beam toward the workpiece, and a beam source and a collimating lens. The first and second optics for receiving the beam and modifying its shape, the position of the first optic in the path of the beam, (ii) the path of the beam. Includes, and / or (iii) a lens manipulation system for varying the distance between the first and second optics within, and / or essentially consists of, or even consists of. Good. The controller may be configured to control the lens manipulation system and vary the shape of the beam. The first optical element comprises, and may consist essentially of, a double concave axicon lens. The second optical element comprises, and may consist essentially of, a biconvex axicon lens. The lens manipulation system may be configured to vary the distance between the first and second optical elements within a range of about 0 mm to about 20 mm. The first optical element has (i) a first surface of a substantially flat surface, (ii) (a) a first portion of convex curvature and (b) a second portion of the substantially flat surface. It has a second surface opposite to, includes a lens, and is essentially made up of, or may be made up of it. The second optical element has (i) a first surface of a substantially flat surface, (ii) (a) a first portion of concave curvature and (b) a second portion of a substantially flat surface. It has a second surface opposite to, includes a lens, and is essentially made up of, or may be made up of it. The lens manipulation system may be configured to position the first and / or second optical element laterally off-center in the path of the beam.

In one aspect, embodiments of the present invention relate to a system for processing workpieces. In various embodiments, the system comprises a beam emitter, a positioning device for varying the beam position of the beam emitter with respect to the workpiece, a variable polarizing device for varying the polarization of the beam, and a positioning device and polarization. Coupled to the vessel, for its processing, the beam emitter is operated to allow the beam to traverse the path across at least part of the workpiece, along the path to consistently polarize the beam against the workpiece. Equipped with a controller to maintain.

In various embodiments, the variable polarizing device comprises a corrugated plate and a rotating element, the rotating element being operated by a controller. For example, the wave plate may be one or more half wave plates, one or more quarter wave plates, or a combination thereof. The beam may be linearly polarized, for example, using a controller that operates a rotating element to maintain a polarization direction parallel to the path.

In some embodiments, the system is further accessible to the controller and comprises a memory for storing data corresponding to the path and a database for storing polarization data for a plurality of materials. The controller is configured to query the database to obtain polarization data about the material of the workpiece, which determines the consistent polarization of the beam. The path may include at least one directional change.

The beam emitter may emit a plurality of beams. The beam emitter may be at least one laser and / or at least one polarized fiber.

In another aspect, the invention relates to a method of processing a workpiece. In various embodiments, the method is the step of operating a beam emitter, directing the beam to traverse a path along the workpiece, and processing the workpiece, wherein the beam has output polarized light. It includes steps and modifying the output polarization along at least part of the path to maintain consistent polarization of the beam to the workpiece throughout the process.

The steps of processing the workpiece may include one or more of cutting, welding, soldering, drilling, or etching the workpiece. The modification step may include directing the beam through the wave plate and varying the rotation angle of the wave plate with respect to the beam. For example, the wave plate may be one or more half wave plates and / or one or more quarter wave plates. The beam may be linearly polarized, for example, and the modification step keeps the direction of polarization of the beam parallel to the path.

In some embodiments, the method further queries the database to obtain polarization data for the material of the workpiece, including a step of storing data corresponding to the path, a step of storing polarization data for multiple materials, and a database. A step, the polarization data, includes a step, which determines the consistent polarization of the beam. The path may include at least one directional change.

In one aspect, embodiments of the present invention feature a laser delivery system for receiving and modifying the spatial power distribution of a radiating beam from a beam source and focusing the radiation with the modified spatial power distribution onto a workpiece. To do. The laser system receives a collimating lens for collimating the radiated beam, a condensing lens for receiving the collimated beam and focusing the beam toward the workpiece, and the radiated beam to modify its spatial power distribution. To control the optics to change the position of the optics in the path of the radiation beam, and the lens manipulation system to achieve a modified spatial power distribution of the target on the workpiece. Including, or essentially consisting of, a controller. The optical element may be placed between the beam source and the collimating lens (ie, placed optically downstream of the beam source and optically upstream of the collimating lens).

Embodiments of the present invention may include one or more of the following in any of the various combinations: The optics include, and essentially a lens, which has (i) a first surface having a truncated conical shape and (ii) a second surface in a substantially flat plane opposite to the first surface. It may or may consist of it. The first surface may face the beam source. The first surface may face upside down from the beam source. The optics include, and essentially a lens, which has (i) a first surface having a truncated spherical shape and (ii) a second surface of a substantially flat surface opposite to the first surface. It may or may consist of it. The first surface may face the beam source. The first surface may face upside down from the beam source. The optics include, and may consist essentially of, or may consist of a meniscus lens. The meniscus lens may be a positive meniscus lens. The meniscus lens may be a negative meniscus lens. The optical element comprises, and may be essentially composed of, fused silica and / or zinc sulfide. The lens manipulation system may be configured to position the optics laterally off-center in the path of the radiated beam.

The laser delivery system may include a second optical element located within the path of the radiated beam. The second optical element may be placed between the focusing lens and the workpiece (ie, placed optically downstream of the focusing lens and optically upstream of the workpiece). The lens manipulation system may be configured to change the position of a second optical element in the path of the radiated beam. The second optical element comprises a lens having (i) a first surface having a truncated conical shape and (ii) a second surface having a substantially flat surface opposite to the first surface. It consists of or may consist of it. The first surface may face the beam source. The first surface may face upside down from the beam source. The second optical element comprises a lens which has (i) a first surface having a truncated spherical shape and (ii) a second surface having a substantially flat surface opposite to the first surface. It consists of or may consist of it. The first surface may face the beam source. The first surface may face upside down from the beam source. The second optical element includes, and may consist essentially of, or may consist of a meniscus lens. The meniscus lens may be a positive meniscus lens. The meniscus lens may be a negative meniscus lens. The second optical element comprises, and may consist essentially of, fused silica and / or zinc sulfide.

The beam source is a beam emitter that emits multiple discrete beams, focusing optics for focusing the multiple beams on a dispersion element, and for receiving the focused beam and dispersing the received focused beam. And the dispersed beam is received, a part of the dispersed beam is transmitted through it as an radiated beam, and the second part of the dispersed beam is positioned to be reflected toward the dispersed element. , Including, or essentially consisting of a partially reflective output coupler. The radiated beam may consist of multiple wavelengths of radiation. Focusing optics may include, or essentially consist of one or more cylindrical lenses, one or more spherical lenses, one or more spherical mirrors, and / or one or more cylindrical mirrors. The dispersion element may include or essentially consist of a diffraction grating (eg, a transmission diffraction grating or a reflection diffraction grating).

In another aspect, embodiments of the present invention feature a laser delivery system for receiving and modifying the spatial power distribution of a radiating beam from a beam source and focusing the radiation with the modified spatial power distribution onto a workpiece. And. The laser delivery system receives the collimating lens for collimating the radiated beam, the condensing lens for receiving the collimated beam and focusing the beam toward the workpiece, and the radiated beam for its spatial power distribution. The first and second optical elements to be modified, (i) the position of the first optical element in the path of the radiating beam, (ii) the position of the second optic element in the path of the radiating beam, and / Or (iii) a lens manipulation system for varying the distance between the first and second optics, and a controller for controlling the lens manipulation system and achieving a modified spatial power distribution of the target on the workpiece. Including, or essentially consisting of. The first and / or second optical element may be located between the beam source and the collimating lens (ie, optically downstream of the beam source and optically upstream of the collimating lens).

Embodiments of the present invention may include one or more of the following in any of the various combinations: The first optical element comprises, and may consist essentially of, a double concave axicon lens. The second optical element comprises, and may consist essentially of, a biconvex axicon lens. The first optical element may be arranged optically upstream of the second optical element. The first optical element may be arranged optically downstream of the second optical element. The lens manipulation system includes first and second optical elements in the range of about 0 mm to about 50 mm, in the range of about 0 mm to about 20 mm, in the range of about 2 mm to about 50 mm, or in the range of about 2 mm to about 20 mm. It may be configured to vary the distance between them. The first optical element has (i) a first surface of a substantially flat surface, (ii) (a) a first portion of convex curvature and (b) a second portion of the substantially flat surface. It has a second surface opposite to, includes a lens, and is essentially made up of, or may be made up of it. The second optical element has (i) a first surface of a substantially flat surface, (ii) (a) a first portion of concave curvature and (b) a second portion of a substantially flat surface. It has a second surface opposite to, includes a lens, and is essentially made up of, or may be made up of it. The first optical element may be arranged optically upstream of the second optical element. The first optical element may be arranged optically downstream of the second optical element. The second surface of the first optical element may face the second surface of the second optical element. The first surface of the first optical element may face the first surface of the second optical element. The first surface of the first optical element may face the second surface of the second optical element. The second surface of the first optical element may face the first surface of the first optical element. The lens manipulation system may be configured to position the first and / or second optical element laterally off-center in the path of the radiated beam. The first optical element comprises, and may consist essentially of, fused silica and / or zinc sulfide. The second optical element comprises, and may consist essentially of, fused silica and / or zinc sulfide.

The beam source is a beam emitter that emits multiple discrete beams, focusing optics for focusing the multiple beams on a dispersion element, and for receiving the focused beam and dispersing the received focused beam. And the dispersed beam is received, a part of the dispersed beam is transmitted through it as an radiated beam, and the second part of the dispersed beam is positioned to be reflected toward the dispersed element. , Including, or essentially consisting of a partially reflective output coupler. The radiated beam may consist of multiple wavelengths of radiation. Focusing optics may include, or essentially consist of one or more cylindrical lenses, one or more spherical lenses, one or more spherical mirrors, and / or one or more cylindrical mirrors. The dispersion element may include or essentially consist of a diffraction grating (eg, a transmission diffraction grating or a reflection diffraction grating).

In yet another aspect, embodiments of the present invention provide a laser delivery system for receiving and modifying the spatial power distribution of a radiating beam from a beam source and focusing the radiation with the modified spatial power distribution onto a workpiece. It is a feature. The laser delivery system receives one or more divergence optics to increase the divergence of the radiated beam, a focusing lens to receive the radiated beam and focus the beam towards the workpiece, and the radiated beam. , Control the lens manipulation system, modify the target, at least one optical element to modify its spatial power distribution, and a lens manipulation system to change the position of at least one optical element in the path of the radiation beam. Includes, or essentially consists of, a controller to achieve the resulting spatial power distribution on the workpiece.

Embodiments of the present invention may include one or more of the following in any of the various combinations: The focusing lens may be optically downstream of one or more divergence increasing optics. At least one optical element may be located optically upstream of the focusing lens. The divergence-increasing optics may include, and essentially consist of, or may consist of a triple collimator. The triple collimator comprises, and may consist essentially of, (i) a first plano-concave lens, (ii) a second meniscus lens, and (iii) a third plano-convex lens. .. The first plano-concave lens may be arranged optically upstream of the second meniscus lens. The second meniscus lens may be arranged optically upstream of the third plano-convex lens. At least one optical element may be placed optically downstream of the first plano-concave lens. At least one optical element may be placed optically upstream of the second meniscus lens and / or the third plano-convex lens. The at least one optical element comprises a lens having (i) a first surface having a truncated conical shape and (ii) a second surface having a substantially flat surface opposite to the first surface. It consists of or may consist of it. At least one optical element comprises a lens having (i) a first surface having a truncated spherical shape and (ii) a second surface having a substantially flat surface opposite to the first surface. It consists of or may consist of it. The at least one optical element comprises, and may consist essentially of, a meniscus lens (eg, a positive meniscus lens or a negative meniscus lens). The lens manipulation system may be configured to laterally decenter the at least one optical element in the path of the radiated beam.

The at least one optical element comprises, consists of, or may consist of a first optical element and a second optical element. The first optical element and the second optical element may be separated by a gap between them. The lens manipulation system includes (i) the position of the first optical element in the path of the radiated beam, (ii) the position of the second optical element in the path of the radiated beam, and / or (iii) the first and second. It may be configured to vary the distance between the optical elements of. The first optical element comprises, and may consist essentially of, a double concave axicon lens. The second optical element comprises, and may consist essentially of, a biconvex axicon lens. The first optical element may be arranged optically upstream of the second optical element. The first optical element may be arranged optically downstream of the second optical element. The lens manipulation system includes first and second optical elements in the range of about 0 mm to about 50 mm, in the range of about 0 mm to about 20 mm, in the range of about 2 mm to about 50 mm, or in the range of about 2 mm to about 20 mm. It may be configured to vary the distance between them. The first optical element has (i) a first surface of a substantially flat surface, (ii) (a) a first portion of convex curvature and (b) a second portion of the substantially flat surface. It has a second surface opposite to, includes a lens, and is essentially made up of, or may be made up of it. The second optical element has (i) a first surface of a substantially flat surface, (ii) (a) a first portion of concave curvature and (b) a second portion of a substantially flat surface. It has a second surface opposite to, includes a lens, and is essentially made up of, or may be made up of it. The first optical element may be arranged optically upstream of the second optical element. The first optical element may be arranged optically downstream of the second optical element. The second surface of the first optical element may face the second surface of the second optical element. The first surface of the first optical element may face the first surface of the second optical element. The first surface of the first optical element may face the second surface of the second optical element. The second surface of the first optical element may face the first surface of the first optical element. The lens manipulation system may be configured to position the first and / or second optical element laterally off-center in the path of the radiated beam. The first optical element comprises, and may consist essentially of, fused silica and / or zinc sulfide. The second optical element comprises, and may consist essentially of, fused silica and / or zinc sulfide.

The beam source is a beam emitter that emits multiple discrete beams, focusing optics for focusing the multiple beams on a dispersion element, and for receiving the focused beam and dispersing the received focused beam. And the dispersed beam is received, a part of the dispersed beam is transmitted through it as an radiated beam, and the second part of the dispersed beam is positioned to be reflected toward the dispersed element. , Including, or essentially consisting of a partially reflective output coupler. The radiated beam may consist of multiple wavelengths of radiation. Focusing optics may include, or essentially consist of, one or more cylindrical lenses, one or more spherical lenses, one or more spherical mirrors, and / or one or more cylindrical mirrors. The dispersion element may include or essentially consist of a diffraction grating (eg, a transmission diffraction grating or a reflection diffraction grating).

These and other objectives, along with the advantages and features of the invention disclosed herein, will become more apparent through reference to the following description, accompanying drawings, and claims. Moreover, it should be understood that the features of the various embodiments described herein are not mutually exclusive and may exist in various combinations and permutations. As used herein, the term "substantially" means ± 10%, and in some embodiments ± 5%. The term "essentially consisting of" means excluding other materials that contribute to function, unless otherwise defined herein. Nevertheless, such other materials may be present in trace amounts, either collectively or individually. As used herein, the terms "radiation" and "light" are used interchangeably unless otherwise indicated. As used herein, "downstream" or "optically downstream" is used to indicate the relative location of the second element, where the light beam strikes the first element after collision. The element is "upstream" or "optically upstream" of the second element. As used herein, the "optical distance" between two components is the distance between the two components actually traveled by the light beam, and the optical distance is the physical distance between the two components. May be equal to, but not necessarily due, for example, due to reflections from the mirror or other changes in the direction of propagation, which are covered by light traveling from one of the components to the other.
The present specification also provides, for example, the following items.
(Item 1)
A method of processing a workpiece, said method:
A relative motion is generated between the laser output beam and the surface of the workpiece to define a processing path, and the thickness of the workpiece along a direction parallel to the laser output beam is the said. The laser output beam varies along the processing path and physically modifies the surface of the workpiece along at least a portion of the processing path.
In the meantime, at least in part, modifying the shape of the laser output beam based on the thickness of the workpiece.
Including methods.
(Item 2)
The method of item 1, wherein the shape of the laser output beam varies between the focused spot and the ring as the thickness of the workpiece increases.
(Item 3)
Item 1 The thickness of the workpiece along a direction parallel to the laser output beam varies, at least in part, due to changes in the angle between the laser output beam and the surface of the workpiece. The method described in.
(Item 4)
The method according to item 1, wherein the shape of the laser output beam is modified while maintaining a substantially constant angle between the laser output beam and the surface of the workpiece.
(Item 5)
The method of item 1, further comprising measuring the thickness of the workpiece during relative motion between the laser output beam and the surface of the workpiece.
(Item 6)
The method of item 1, wherein the shape of the laser output beam is modified based on the composition of the workpiece.
(Item 7)
The method according to item 1, wherein the laser output beam is composed of a plurality of wavelengths.
(Item 8)
A system for processing workpieces, said system
A beam emitter for emitting a laser output beam,
A positioning device for varying the position of the laser output beam with respect to the workpiece, and
Means for modifying the shape of the laser output beam and
A controller coupled to the positioning device and the shape-modifying means, which (i) operates the beam emitter and routes the laser output beam across at least a portion of the workpiece. With a controller that traverses, physically modifies its surface, and (ii) at least partially modifies the shape of the laser output beam based on the thickness of the workpiece along the path.
The system.
(Item 9)
The beam emitter comprises a processing head from which the laser output beam is emitted, and the shape-modifying means include (i) one or more optical elements in the processing head and (ii) in the processing head. 8. The system of item 8, comprising a second controller for modifying the position of at least one of the optical elements.
(Item 10)
8. The system of item 8, wherein the controller is configured to vary the output power of the beam emitter along the path.
(Item 11)
8. The system of item 8, wherein the controller is configured to vary the shape of the laser output beam based on the composition of the workpiece.
(Item 12)
8. The system of item 8, further comprising a database containing a plurality of records, each of the plurality of records relating a laser output beam shape to a workpiece parameter.
(Item 13)
The system of item 12, wherein the workpiece parameter comprises at least one of a workpiece thickness and a workpiece composition.
(Item 14)
The beam emitter
A beam source that emits multiple discrete input beams and
Focusing optics for focusing the plurality of input beams on the dispersion element,
A dispersion element for receiving the focused beam and dispersing the received focused beam,
A partially reflected output coupler, the partially reflected output coupler receives the dispersed beam, transmits a part of the dispersed beam through it as the laser output beam, and the dispersed beam. With a partial reflection output coupler positioned to reflect the second portion of the
8. The system of item 8, wherein the laser output beam comprises a plurality of wavelengths.
(Item 15)
A method of joining the first and second workpieces at a processing point, wherein the first and second workpieces overlap and / or are in close proximity to each other at the processing point.
The laser output beam is focused close to the processing point to melt at least one portion of the first or second workpiece, thereby splicing both the first and second workpieces together. To match and
During that time, the shape of the laser output beam is changed without causing a relative motion between the laser output beam and the first and second workpieces.
Including methods.
(Item 16)
15. The method of item 15, wherein the shape of the laser output beam varies between focused spots and rings.
(Item 17)
The method of item 15, wherein the laser output beam comprises a plurality of wavelengths.
(Item 18)
A method of joining first and second workpieces using a laser output beam capable of focusing on a minimum spot size and using welding with a spatial range greater than the minimum spot size. ,
Focusing the laser output beam onto at least one of the first or second workpieces to cause melting thereof.
To vary the shape of the laser output beam and increase the size of the weld without causing relative motion between the laser output beam and the first and second workpieces.
Including methods.
(Item 19)
18. The method of item 18, wherein the shape of the laser output beam varies between focused spots and rings.
(Item 20)
Item 18. The method of item 18, wherein the laser output beam comprises a plurality of wavelengths.
(Item 21)
A system for processing workpieces, said system
Beam emitter and
A positioning device for varying the beam position of the beam emitter with respect to the workpiece, and
A variable polarizing device for varying the polarization of the beam,
A beam shaper for changing the shape of the beam and
A controller coupled to the positioning device, the polarizing device, and the beam forming device, the controller operating the beam emitter for processing the workpiece, and at least the workpiece on the beam. With a controller that traverses a path across a portion and, at least in part, varies the polarization and / or shape of the beam along the path based on one or more properties of the workpiece.
The system.
(Item 22)
21. The system of item 21, wherein the controller is configured to maintain linearly polarized light of the beam, having a polarization direction substantially parallel to the path as the beam traverses the path.
(Item 23)
21. The system of item 21, wherein the controller is configured to vary the polarization eccentricity of the beam, at least in part, based on the thickness of the workpiece.
(Item 24)
21. The system of item 21, wherein the controller is configured to vary the polarization of the beam between a linearly polarized state and a radially polarized state.
(Item 25)
21. The system of item 21, wherein the variable polarizing device comprises a corrugated plate and a rotating element, the rotating element being operated by the controller.
(Item 26)
25. The system of item 25, wherein the wave plate comprises at least one of a half wave plate or a quarter wave plate.
(Item 27)
25. The system of item 25, wherein the beam is linearly polarized and the controller operates the rotating element to maintain a polarization direction parallel to the path.
(Item 28)
The variable polarizing device includes a compensator plate, a fixed birefringence wedge arranged over the compensator plate, a movable birefringence wedge arranged over the fixed birefringence wedge, and a translation element. 21. The system of item 21, wherein the element is operated by said controller.
(Item 29)
21. The system of item 21, wherein the variable polarizing device comprises a radial polarizing converter.
(Item 30)
A memory that is accessible to the controller, wherein the memory stores data corresponding to the path.
A database for storing polarization data for multiple materials
The controller is configured to query the database, obtain the polarization data for the material of the workpiece, and at least partially vary the polarization of the beam based on the polarization data. The system according to item 21.
(Item 31)
21. The system of item 21, wherein the route comprises at least one directivity change.
(Item 32)
The beam emitter
A beam source that emits multiple discrete input beams and
Focusing optics for focusing the plurality of input beams on the dispersion element,
A dispersion element for receiving the focused beam and dispersing the received focused beam,
A partial reflection output coupler, the partial reflection output coupler receives the dispersed beam, transmits a part of the dispersed beam through it as a beam of the beam emitter, and the dispersed beam. With a partial reflection output coupler positioned to reflect a second portion of the beam towards the dispersion element
21. The system of item 21, wherein the beam of the beam emitter comprises a plurality of wavelengths.
(Item 33)
The beam forming machine
A collimating lens for collimating the beam received from the beam emitter,
A focusing lens for receiving the collimated beam and focusing the beam toward the workpiece.
An optical element arranged between the beam source and the collimating lens, wherein the optical element receives the beam and modifies its shape.
With a lens manipulation system for changing the position of the optical element in the path of the beam
21. The system of item 21, wherein the controller controls the lens operating system and is configured to vary the shape of the beam.
(Item 34)
Item 33, wherein the optical element comprises a lens having (i) a first surface having a truncated conical shape and (ii) a second surface having a substantially flat surface opposite to the first surface. The system described in.
(Item 35)
Item 33, wherein the optical element comprises a lens having (i) a first surface having a truncated spherical shape and (ii) a second surface having a substantially flat surface opposite to the first surface. The system described in.
(Item 36)
33. The system of item 33, wherein the optical element comprises a meniscus lens.
(Item 37)
33. The system of item 33, wherein the lens operating system is configured to position the optical element laterally off-center in the path of the beam.
(Item 38)
Further comprising a second optical element located between the focused lens and the workpiece, the lens manipulation system is configured to change the position of the second optical element in the path of the beam. The system according to item 33.
(Item 39)
The second optical element comprises a lens having (i) a first surface having a truncated conical shape and (ii) a second surface having a substantially flat surface opposite to the first surface. , Item 38.
(Item 40)
The second optical element comprises a lens having (i) a first surface having a truncated spherical shape and (ii) a second surface having a substantially flat surface opposite to the first surface. , Item 38.
(Item 41)
38. The system of item 38, wherein the second optical element comprises a meniscus lens.
(Item 42)
The beam forming machine
A collimating lens for collimating the beam received from the beam emitter,
A focusing lens for receiving the collimated beam and focusing the beam toward the workpiece.
A first and second optical element disposed between the beam source and the collimating lens, wherein the first and second optical elements receive the beam and modify its shape. With the first and second optics,
(I) the position of the first optical element in the path of the beam, (ii) the position of the second optical element in the path of the beam, or (iii) between the first and second optical elements. With a lens manipulation system to change at least one of the distances
21. The system of item 21, wherein the controller controls the lens operating system and is configured to vary the shape of the beam.
(Item 43)
42. The system of item 42, wherein the first optical element comprises a double concave axicon lens and (ii) the second optical element comprises a double convex axicon lens.
(Item 44)
42. The system of item 42, wherein the lens manipulation system is configured to vary the distance between the first and second optical elements within a range of about 0 mm to about 20 mm.
(Item 45)
The first optical element has (i) a first surface of a substantially flat surface, (ii) (a) a first portion of convex curvature, and (b) a second portion of the substantially flat surface. With a lens having a second surface opposite to that of
The first optical element comprises (i) a first surface of a substantially flat surface, (ii) (a) a first portion of concave curvature and (b) a second portion of the substantially flat surface. 42. The system of item 42, comprising a lens having a second surface opposite to that of.
(Item 46)
42. The lens manipulation system is configured to position at least one of the first optical element or the second optical element laterally off-center in the path of the beam. System.

In drawings, similar reference characters generally refer to the same part throughout different drawings. Also, the drawings are not necessarily on an exact scale, but instead are generally emphasized in illustrating the principles of the invention. In the following description, various embodiments of the present invention will be described with reference to the following drawings.

FIG. 1 illustrates a conventional method of cutting a curve out of a material using the polarization of a fixed cutting beam. FIG. 2A illustrates exemplary regulation of polarized light along a cutting path within a material according to various embodiments of the invention. FIG. 2B illustrates exemplary adjustment of polarized light according to material thickness according to various embodiments of the present invention. FIG. 2C illustrates exemplary adjustment of polarized light from linearly polarized light to radially polarized light according to various embodiments of the present invention. FIG. 3A-3G illustrates an exemplary system for varying beam polarization, at least in part, based on treatment direction or material thickness, according to various embodiments of the invention. FIG. 3A-3G illustrates an exemplary system for varying beam polarization, at least in part, based on treatment direction or material thickness, according to various embodiments of the invention. FIG. 3A-3G illustrates an exemplary system for varying beam polarization, at least in part, based on treatment direction or material thickness, according to various embodiments of the invention. FIG. 3A-3G illustrates an exemplary system for varying beam polarization, at least in part, based on treatment direction or material thickness, according to various embodiments of the invention. FIG. 3A-3G illustrates an exemplary system for varying beam polarization, at least in part, based on treatment direction or material thickness, according to various embodiments of the invention. FIG. 3A-3G illustrates an exemplary system for varying beam polarization, at least in part, based on treatment direction or material thickness, according to various embodiments of the invention. FIG. 3A-3G illustrates an exemplary system for varying beam polarization, at least in part, based on treatment direction or material thickness, according to various embodiments of the invention. FIG. 4A illustrates a method for cutting or welding a material using a self-regulating polarized beam according to various embodiments of the present invention. FIG. 4B-4D is a graph of cutting speed as a function of workpiece thickness comparing controlled polarized light according to various embodiments of the present invention with a laser beam using a conventional unpolarized beam. FIG. 4B-4D is a graph of cutting speed as a function of workpiece thickness comparing controlled polarized light according to various embodiments of the present invention with a laser beam using a conventional unpolarized beam. FIG. 4B-4D is a graph of cutting speed as a function of workpiece thickness comparing controlled polarized light according to various embodiments of the present invention with a laser beam using a conventional unpolarized beam. FIG. 5 is a schematic diagram of a laser beam delivery system according to various embodiments of the present invention. FIG. 6 is a schematic view of a flat upper conical optical element according to various embodiments of the present invention. FIG. 7A is a graph of BPP variation as a function of the distance of the fused silica flat top conical optics from the beam source according to various embodiments of the present invention. FIG. 7B is a graph of BPP variation as a function of the distance of the zinc sulfide flat upper conical optics from the beam source according to various embodiments of the present invention. FIG. 8A is a schematic representation of a laser delivery system with off-center optical elements according to various embodiments of the present invention. 8B-8D depict a beam profile as a function of off-center distance produced by the laser delivery system of FIG. 8A. FIG. 9 is a schematic view of a flat upper spherical optical element according to various embodiments of the present invention. FIG. 10A is a graph of BPP variation as a function of the distance of the fused silica flat top spherical optics from the beam source according to various embodiments of the present invention. FIG. 10B is a graph of BPP variation as a function of the distance of the zinc sulfide flat upper spherical optics from the beam source according to various embodiments of the present invention. 11A-11C depict a beam profile as a function of off-center distance produced by a laser delivery system incorporating the optical elements of FIG. 9 according to various embodiments of the present invention. FIG. 11D is a graph of irradiance as a function of position for the two-peak beam profile depicted in FIG. 11C. FIG. 12A is a schematic representation of a portion of a laser delivery system having two axicon lens optics according to various embodiments of the present invention. 12B and 12C depict the geometric design parameters of an axicon lens according to various embodiments of the present invention. 12B and 12C depict the geometric design parameters of an axicon lens according to various embodiments of the present invention. FIG. 13 is a graph of BPP variation as a function of the clearance distance between positive and negative axicon lenses according to various embodiments of the present invention. FIG. 14 depicts beam profiles at different clearance distances between positive and negative axicon lenses according to various embodiments of the present invention. FIG. 15 depicts beam profiles at different clearance distances between positive and negative axicon lenses laterally off-center in the beam path according to various embodiments of the present invention. FIG. 16A is a schematic representation of a portion of a laser delivery system having a pair of phase plate lenses according to various embodiments of the present invention. 16B and 16C depict the geometric design parameters of a phase plate lens according to various embodiments of the present invention. FIG. 16D is a graph of BPP as a function of the inner diameter of the paired phase plates according to various embodiments of the present invention. FIG. 16E is a graph of optimized inner diameters of paired phase plates as a function of separation from the input fiber end cap according to various embodiments of the present invention. FIG. 16F is a graph of BPP variation as a function of the clearance distance between paired phase plate lenses according to various embodiments of the present invention. FIG. 16G depicts beam profiles at different clearance distances between paired phase plate lenses according to various embodiments of the present invention. FIG. 17A is a schematic diagram of a meniscus lens optical element according to various embodiments of the present invention. FIG. 17B is a graph of BPP variation as a function of the distance of the fused silica meniscus lens optics from the beam source according to various embodiments of the present invention. FIG. 18A is a schematic representation of a partial laser beam delivery system incorporating a triple collimator for increased beam divergence according to various embodiments of the present invention. FIG. 18B is a graph of BPP variation as a function of the distance of the flat upper spherical optics from the beam source in the laser delivery system of FIG. 18A according to various embodiments of the present invention. FIG. 18C is a graph of BPP variation as a function of the distance of the meniscus lens optics from the beam source in the laser delivery system of FIG. 18A according to various embodiments of the present invention. FIG. 18D is a schematic representation of a partial laser beam delivery system incorporating a triple collimator for increased beam divergence and paired phase plate optics according to various embodiments of the present invention. FIG. 18E is a graph of BPP variation as a function of the clearance distance between paired phase plate lenses in the laser beam delivery system of FIG. 18D according to various embodiments of the present invention. FIG. 19 is a schematic representation of a wavelength beam combination laser system that can be utilized to supply an input beam for a laser beam delivery system according to various embodiments of the present invention. FIG. 20 is a schematic diagram of a laser system according to various embodiments of the present invention. FIG. 21 is a series of images depicting exemplary beam shapes utilized according to various embodiments of the present invention. 22A and 22B are schematic views of workpieces processed using laser beams with different shapes according to various embodiments of the present invention. 23A-23D are a series of schematic views of a welding process utilizing laser beams having a plurality of different beam shapes according to various embodiments of the present invention.

The sides and embodiments generally adjust the polarization and / or shape of the laser beam used in the production to produce better production results, including clean cut surfaces and welds with little debris. Regarding the field. In various embodiments, therefore, the invention relates to optimizing the polarization and / or shape of the laser beam for the material being treated. More specifically, systems and methods for adjusting polarization selectively select that polarization based on, for example, the geometry, material, and thickness of the material being processed, and the instantaneous orientation of the beam relative to it. It may involve a step of varying the orientation of the wave plate through which the beam passes. The approaches and embodiments described herein may be applied to single and dual beam output systems that use polarization-maintaining optical fibers and deliver the output beam from the laser system to the laser head. In some cases, these laser systems may be wavelength beam combination systems that produce multi-wavelength output beams.

Therefore, embodiments of the present invention establish an optimal polarization direction for a given material and maintain this direction relative to the process as the process progresses. This is in contrast to the behavior of prior art systems as illustrated in FIG. 1, which does not alter the polarization direction. In FIG. 1, the sheet 100 of material is processed by a linearly polarized beam that follows a desired cutting path 102, which can be curved. The linearly polarized light shown in 104 maintains a fixed orientation regardless of the variable orientation of the beam with respect to the material 100. In many systems, optimal beam polarization is parallel to the direction of processing. In FIG. 1, this happens only once, and in fact, in most places, the polarization is unfavorably perpendicular to the processing direction. This can delay processing, produce debris, result in incomplete cutting, and so on.

One optimal behavior for an exemplary system is illustrated in FIG. 2A. The polarization orientation 204 of the processing beam remains parallel to the processing direction throughout the processing path 102. Another optimal behavior for the exemplary system is illustrated in FIG. 2B. The polarization state 210 of the processed beam changes from linearly polarized light to elliptical polarized light and circularly polarized light as the thickness of the material 100 increases. In yet another embodiment illustrated in FIG. 2C, the polarization state 210 of the processed beam changes from linearly polarized light to radially polarized light along the processing path 102. The processing pathways in FIGS. 2B and 2C are substantially linear, but in embodiments of the present invention, the processing pathways may include one or more directional changes, as shown in FIG. 2B. In general, the processing pathways may be curved or linear, and "linear" processing pathways can be characterized by one or more directional changes, i.e., linear processing pathways are not necessarily parallel to each other. It may consist of one or more substantially straight sections.

A representative system for carrying out polarization variation according to an embodiment of the present invention is shown in FIGS. 3A-3C. Referring to FIG. 3A, system 300 includes a laser (or other beam emitter such as a polarizing fiber) 305 and a controller 310. The controller 310 controls the operation of the laser 305 (ie, activates the laser 305 and, if necessary, controls beam parameters such as intensity during processing). The controller also operates a conventional positioning system 315 and a polarization controller 320. The positioning system 315 may be any controllable optical system, mechanical system, or optical mechanical system for directing the beam through a processing path along a two- or three-dimensional workpiece. During processing, controller 310 may operate the positioning system 315 and laser 305 such that the laser beam traverses the processing path along the workpiece. The processing path may be provided by the user and stored in the onboard or remote memory 325, which is also required for the parameters related to the type of processing (cutting, welding, etc.) and for performing the processing. The beam parameter may be stored. In this regard, the local or remote database 330 may maintain a library of materials and thicknesses that the system 300 will process, depending on the user's choice of material parameters (material type, thickness, etc.). The controller 310 queries the database 330 and obtains the corresponding parameter values. The stored values may include polarization orientation and / or states suitable for the material.

As deeply understood in plotting and scanning techniques, the required relative motion between the beam and the workpiece is the optical deflection of the beam with a movable mirror, a gantry, a feed screw, or a laser with other arrays. It may be produced by physical movement of the work piece and / or mechanical arrangement for moving the workpiece rather than (or in addition to) the beam. In some embodiments, the controller 310 may receive feedback from the feedback unit 335 regarding the position and / or processing effectiveness of the beam with respect to the workpiece, which will be connected to a suitable monitoring sensor. .. In response to the signal from the feedback unit 335, controller 310 modifies the path, composition, and / or polarization of the beam.

In one embodiment shown in FIGS. 3B and 3C, polarization adjustment is performed within the laser head component 350, which is the last optical mechanical part of the laser system that emits a beam, typically used in manufacturing. is there. The laser head 350 includes a collimating lens 355, an adjustment / rotating wave plate 360, and a focusing lens 365 for directing the beam 370 onto the surface of the workpiece. The wave plate 360 may be a quarter wave plate, a half wave plate, or another wave plate for rotating the polarized light of the beam 370. Referring to FIG. 3A-3C, the conventional electromechanical rotation device 375 rotates the wave plate 360 as the beam moves through the processing path 102 under the control of the controller 310, and thus the beam 370 with respect to the path 102. Provides a consistent polarization direction for. In other configurations, multiple corrugated plates may be employed and rotated separately by individual rotating devices 375. The use of multiple corrugated plates can improve response time. The polarization of the beam 370 is shown in the first orientation 380a prior to the encounter with the wave plate 360 and in the second orientation 380b after passing through the wave plate 360.

In one embodiment shown in FIGS. 3D and 3E, polarization adjustment is also performed within the laser head component 350. The laser head 350, like the laser head 350 depicted in FIG. 3B, includes a collimating lens 355 and a focusing lens 365 for directing the beam 370 onto the surface of the workpiece. In the embodiment of FIG. 3D, the laser head 350 includes a Babinet-Soleil compensator 385 between the collimating lens 355 and the focusing lens 365. As is known in the art, the Babinet-Soleil compensator 385 is a continuously variable optical retarder capable of altering the polarization of light traveling through it from linear to circular and any elliptical polarization state in between. .. In various embodiments, the Babinet-Soleil compensator 385 comprises, comprises, and consists essentially of a compensator plate 386, a fixed birefringence wedge 387, and a movable birefringence wedge 388. The major axis of the compensator plate 386 is typically perpendicular to the major axis of the wedges 387 and 388. The movement of the wedge 388 with respect to the plate 386 and the wedge 377 modifies the polarization state of the beam 370 to any elliptical state between linear and circular. With reference to FIGS. 3A, 3D, and 3E, the conventional electromechanical translation device 389, under the control of controller 310, as the beam travels through the processing path 102 (eg, as the thickness of the workpiece changes). , The movable wedge 388 of the Babinet-Soleil compensator 385 is translated, thereby changing the polarization state along the path 102 as a function of the thickness of the workpiece. For example, the roundness of the polarized state of the beam 370 (ie, the transition from linear to elliptical or circular) can be increased as the thickness of the workpiece increases. The polarization of the beam 370 is shown in the first state 390a prior to the encounter with the Babinet-Soleil compensator 385 and in the second state 390b after passing through the Babinet-Soleil compensator 385.

In another embodiment shown in FIGS. 3F and 3G, polarization adjustment is also performed within the laser head component 350. The laser head 350 includes a collimating lens 355 and a focusing lens 365 for directing the beam 370 onto the surface of the workpiece, similar to the laser head 350 depicted in FIGS. 3B and 3D. In the embodiment of FIG. 3F, the laser head 350 includes a radial polarizing converter 391 between the collimating lens 355 and the focusing lens 365. As is known in the art, the radial polarization converter 391 comprises, consists of, or may consist of a glass wave plate that converts linearly polarized light into radial or azimuthally polarized light. For example, the radial polarization converter 391 may be a half-wave plate with continuously varying slow-axis or spatially deformed quarter-wave plates with radial symmetry. The radial polarization converter 391 is an S-wave plate radial polarization converter or Edmund Optics Inc. available from nanostructured lattices, such as UAB Altechna (Vilnius, Lithuania). Has one of the radial polarizing converters available from (Barrington, NJ) on it, includes a glass plate, and consists of or may consist essentially of it. In another embodiment, the radial polarization converter 391 is available from a liquid crystal, eg, Arcopix (Neuchatel, Switzerland), where the liquid crystal molecules are specifically matched to produce the desired radial or azimuth polarization. It includes, and may essentially consist of, or may consist of a directional polarization converter. The movement of the radial polarization converter 391 within the path of the beam 370 modifies the polarization state of the beam 370 from linear to radial or azimuth and vice versa. In various embodiments, the radially polarized beam 370 can be focused to a spot size smaller than the beam 370 with linearly polarized light. With reference to FIGS. 3A, 3F, and 3G, the conventional electromechanical translation device 389 translates the radial polarization converter 391 as the beam moves through the processing path 102 under the control of the controller 310, thereby. , The polarization state is changed along the path 102. The polarization of the beam 370 is a first state 392a (ie, linearly polarized light) prior to the encounter with the radial polarization converter 391 and a second state 392b (ie, radial polarization) after passing through the radial polarization converter 391. ) And.

FIG. 4A illustrates a representative method 400 in which the system 300 is operated to perform a cutting operation. In the first step 410, the user preprograms the desired route into the system 300 using any suitable input device or using file transfer. In step 420, controller 310 analyzes the curve, features (eg, thickness), and cutting direction of the path, queries database 330, and, if necessary, determines the rate at which cutting can occur, and cutting direction. Determines the optimum polarization direction and / or state of the laser beam for. During the operation shown in step 430, the controller 330 operates the laser 305 and subsystems 315, 320, cutting along a pre-programmed path to maintain proper polarization. If the composition and / or thickness of the material being processed changes, the location and nature of the change may be programmed and the controller 310 appropriately includes laser beam parameters (including polarization and / or beam shape). Can be adjusted. Optimal cutting, welding, or manufacturing solutions are not necessarily the cleanest cut surfaces or welds, as additional steps in the process (eg, deburring, grinding, and / or polishing) may still be required. Please note that there may be cases. Therefore, overall optimizations can be obtained based on the desired output, and the methods and systems are configured to produce their desired results, whatever they may be. As described above, cutting is only one embodiment of laser processing that can benefit from the approach of embodiments of the present invention.

The controller 310 may be provided as either software, hardware, or some combination thereof. For example, the system is a Pentium® or Celeron family processor manufactured by Intel Corporation (Santa Clara, Calif.), A 680x0 and POWER PC family processor manufactured by Motorola Corporation (Schaumbrug, California), and / Or Advanced Micro Devices, Inc. It may be implemented on one or more conventional server class computers, such as a PC with a CPU board, containing one or more processors, such as ATHLON line processors manufactured by (Sunnyvale, Calif.). The processor may also include a main memory unit for storing programs and / or data related to the methods described above. The memory includes one or more application-specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), electrically erasable programmable read-only memory (EEPROM), programmable read-only memory (PROM), programmable logic devices (programmable logic devices). It may include random access memory (RAM), read-only memory (ROM), and / or flash memory resident on commonly available hardware such as a PLD) or read-only memory device (ROM). In some embodiments, the program may be provided using external RAM and / or ROM such as optical disks, magnetic disks, and other commonly used storage devices. With respect to embodiments in which the functionality is provided as one or more software programs, the program may be any number of FORTRAN, PASCAL, JAVA®, C, C ++, C #, BASIC, various scripting languages, and / or HTML. It may be written in any of the higher level languages. In addition, the software may be implemented in assembly language for microprocessors residing on the target computer. For example, the software may be implemented in Intel 80x86 assembly language if configured to boot on an IBM PC or PC clone. The software is embodied on the product, including, but not limited to, floppy (registered trademark) disks, jump drives, hard disks, optical disks, magnetic tapes, PROMs, EPROMs, EEPROMs, field programmable gate arrays, or CD-ROMs. You may.

Although the methods described herein for improving processing work well for linearly polarized beams (delivered via a free space laser or polarization maintenance fiber), the technique also works well. Works well with an elliptical polarized beam (biased to one polarized light). For example, a beam from standard multimode fiber is likely to be polarized in an elliptical shape and can benefit from the approaches described herein.

Embodiments of the present invention may advantageously be utilized for more efficient cutting of various materials, such as metallic materials. FIG. 4B is a graph of achievable cutting rates as a function of workpiece thickness for workpieces made of 304 stainless steel under nitrogen gas flow. Four different laser systems were utilized for cutting. First, a laser system according to an embodiment of the invention, which operates at a power of 1 kW and utilizes a 58 μm polarization-maintaining optical output fiber to produce a linearly polarized laser output beam, polarizes the workpiece in the polarization direction. It was used to cut in parallel and vertical directions. Trend line 440 describes the achievable cutting speed for a beam polarized parallel to the cutting direction, and trend line 445 describes the achievable cutting speed for a beam polarized perpendicular to the cutting direction. As shown, parallel polarized beams allow significantly higher cutting speeds than vertically polarized beams, especially for thinner workpieces. Trend lines 450 and 455 depict data on two different commercially available 1 kW laser systems with unpolarized output beams (ie, utilizing output fiber optic cables that are not polarized maintenance fibers). As shown, the unpolarized beam allows faster cutting compared to the vertically polarized beam of trend line 445, but is slower than the parallel polarized beam of trend line 440. Trend line 460 depicts data for a 2 kW laser that has a 100 μm output fiber but also produces an unpolarized beam. As would be expected, this more powerful laser system allows faster cutting speeds than lower power laser systems, but the parallel polarized beam of trend line 440 has lower power and more. Despite operating with smaller output fibers, the advantage of cutting at higher speeds is diminished and even disappears for thinner workpieces.

FIG. 4C is a graph of cutting speed achievable as a function of workpiece thickness for workpieces made of 3003 aluminum under nitrogen gas flow. The laser system utilized is the same as that described above with respect to FIG. 4B. As shown, the parallel polarized beam represented by the trend line 440 exhibits the best cutting performance, and the performance of the parallel polarized beam is that of the trend line 460 2 kW, 100 μm unpolarized beam, especially with respect to thinner workpiece thickness. Even better than the one. As in FIG. 4B, the vertically polarized beam of trend line 445 describes the worst performance and emphasizes the advantageous effect of embodiments of the present invention in which the polarization direction is maintained parallel to the cutting direction.

FIG. 4D is a graph of cutting speed achievable as a function of workpiece thickness for workpieces made of brass under nitrogen gas flow. The laser system utilized is the same as that described above with respect to FIG. 4B. As shown, the parallel polarized beam represented by trend line 440 exhibits fast cutting performance, especially for thinner workpiece thicknesses. The parallel polarized beam represented by trend line 440 also exhibits a much faster cutting rate than the comparable 1 kW unpolarized beam represented by trend line 450. As in FIGS. 4B and 4C, the vertically polarized beam of trend line 445 describes the worst performance and, in fact, does not have the ability of cutting speeds to be evaluated for workpieces with a thickness of 3 mm.

Embodiments of the invention combine beam polarization adjustment in response to workpiece material and / or physical properties, using techniques for shaping the beam and / or adjusting the beam's BPP. Replace. FIG. 5 depicts a schematic of a laser beam delivery system 500 incorporating a beam manipulating optical element according to an embodiment of the present invention. In various embodiments, the laser beam delivery system 500 may be located, for example, within a laser-based cutting head or welding head (eg, cutting head 350) and is utilized to adjust the polarization of the output beam. It may be combined with various components thereof (for example, an optical element, a controller, etc.). The beam delivery system 500 comprises a beam delivery fiber and a collimating lens 510, which are connected to the rest of the laser generation system (eg, the WBC laser system, not shown in FIG. 5) and are terminated by a fiber end cap 505. It may feature an focusing lens 515 and an optical element 520 positioned between the end cap 505 and the collimating lens 510. In various embodiments of the invention, characterized by combined functionality for beam shaping and polarization regulation, elements such as the collimating lens 510 and the focusing lens 515 may be shared between those functions. That is, the laser beam delivery system may, in various embodiments, have various optical elements that facilitate both beam shaping and polarization regulation. In various embodiments, the optics 520 are placed in close proximity to the fiber end cap 505 to minimize the size of the beam striking the optics 520. Refraction of smaller beams may be done using optics with smaller geometric dimensions of optics, or higher sensitivities may be used to vary the output profile. FIG. 5 also depicts an optional second optical element 525 placed between the focusing lens 515 and the workpiece 530. The workpiece 530 may include, or essentially consist of, for example, one or more parts (eg, metal parts) that are welded, perforated, and / or cut by a beam focused by a focusing lens 515. .. In various embodiments, the first optical element 520 is disposed between the focusing lens 515 and the workpiece 530, and the second optical element 525 is omitted. Each of the optical elements 520, 525 may include, or essentially consist of, for example, a phase plate.

The position of the first optical element 520 and / or the second optical element 525 includes, or from, for example, one or more machine or motor driven translation stages 535 that can move along two or three axes. It may be translated into the beam profile through the use of a lens manipulation system, which is essentially possible. The lens manipulation system may respond to controller 540. Controller 540 is a BPP or other measurement of the desired target radiation power distribution and / or beam quality (eg, by the user and / or distance to the workpiece, workpiece composition, workpiece topography, workpiece thickness. In response to an input based on one or more properties of the workpiece to be processed, such as positioning the optics 520 and / or the optics 525, the beam 545 being manipulated using the target radiation power distribution or beam quality. It may be configured to strike the work piece 530. Controller 540 may be programmed to achieve the desired power distribution and / or output BPP and / or beam quality through specific optics positioning, as detailed herein. Controller 540 may be provided as either software, hardware, or some combination thereof. For example, the system may be a Pentium® or Celeron family processor from Intel Corporation (Santa Clara, California), a 680x0 and POWER PC family processor from Motorola Corporation (Schaumburg, California), and / or AdvancedM. , Inc. It may be mounted on one or more conventional server class computers, such as a PC with a CPU board containing one or more processors of the ATHLON line, such as (Sunnyvale, California). The processor may also include a main memory unit for storing programs and / or data related to the methods described herein. The memory includes one or more application-specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), electrically erasable programmable read-only memory (EEPROM), programmable read-only memory (PROM), programmable logic devices (programmable logic devices). It may include random access memory (RAM), read-only memory (ROM), and / or flash memory resident on commonly available hardware such as PLD) or read-only memory devices (ROM). In some embodiments, the program may be provided using external RAM and / or ROM such as optical disks, magnetic disks, and other commonly used storage devices. For embodiments in which the functionality is provided as one or more software programs, the program may be any number such as FORTRAN, PASCAL, JAVA®, C, C ++, C #, BASIC, various scripting languages, and / or HTML. It may be written in any of these high-level languages. In addition, the software may be implemented in a microprocessor-oriented assembly language residing on the target computer, for example, the Intel 80x86 assembly if the software is configured to run on an IBM PC or PC clone. It may be implemented in a language. Software includes, but is not limited to, floppy (registered trademark) disks, jump drives, hard disks, optical disks, magnetic tapes, PROMs, EPROMs, EEPROMs, field programmable gate arrays, or CD-ROMs. You may.

FIG. 6 is a schematic view of an optical element 600 having a truncated conical shape (flat upper conical shape or tapered cylindrical shape) according to an embodiment of the present invention. For example, the optical element 600 may be utilized as an optical element 520 and / or an optical element 525 within the delivery system 500. The parameters D, d, θ, and H are slopes that define the outer diameter, inner diameter (which can correspond to the beam size of the beam when striking the optics), and the maximum arrow (or "hanging", h), respectively. Geometric design parameters for the angle, the separation of the outer ring of the beam from the center of the spot of the beam, and the thickness of the optical element 600. Geometric optics ray tracing may be used to design optical elements according to embodiments of the present invention based on energy conservation, optical path length homeostasis, and Snell's law. The lens design and its surface profile can, for example, transform the beam profile from Gauss with the desired intensity distribution to a Vessel laser beam.

Table 1 comprises, for example, two different materials, namely fused silica and zinc sulfide (for example, ZnS MultiSpectal available from II-VI Inc. (Saxonburg, PA)), consisting of or consisting of it. An exemplary design value for the optical element 600 is provided.

7A and 7B are graphs of BPP at different distances from the fiber end cap 505 to the exemplary fused silica (FIG. 7A) and zinc sulfide (FIG. 7B) optics 600 with the design parameters provided in Table 1. Is. In the plot, the initial position of the optical element 600 is assumed to be end cap 505 to 25 mm. As shown, in both cases the BPP of the beam can be increased to about 4 to about 12 via a displacement of the optics 600 of only about 30 mm. The slope of this change in BPP as a function of displacement may be modified via a change in the numerical aperture of the fiber output at the end cap 505. Beam profiles at a distance of 50 mm from the optical element 600 to the fiber end cap 505 are also shown in FIGS. 7A and 7B.

A tuned beam profile with two peaks on one axis traverses the optics 600 (or other optics detailed herein) in the beam path, as shown in FIG. 8A. Can be obtained by off-center positioning (ie, introducing it partially into the input laser beam). Depending on the degree of introduction, the beam profile of the output laser beam can be optimally adapted for a variety of laser applications. In FIG. 8B-8D, beam profiles at different off-center distances (0 mm, 2 mm, and 4 mm) for the optical element 600 at a distance of 40 mm to the end cap 505 are shown. FIG. 8E is a graph of irradiance as a function of position for the beam profile depicted in FIG. 8D, clearly showing the two-peak properties of the beam profile. In various embodiments, the variation in BPP at different centers of the optics 600 is about zero while the irradiance changes as a function of position across the beam profile.

The optics according to embodiments of the present invention may also have a truncated spherical (ie, flat top spherical) configuration and may be used to produce a Bessel beam profile. The geometric design for the optical element 900 according to such an embodiment is graphically depicted in FIG. The optical element 900 may be utilized as an optical element 520 and / or an optical element 525 within the delivery system 500. The design parameters are the same as those detailed above for the flat top conical optics 600, except for the radius of curvature R, which also results in the maximum droop of the annular beam ring from the center of the beam spot ( h) and the separation is defined.

Table 2 provides exemplary design values for an exemplary optical element 900 comprising, consisting of, or consisting of two different materials, namely fused silica and zinc sulfide.

10A and 10B are graphs of BPP at different distances from the fiber end cap 505 to the exemplary fused silica (FIG. 10A) and zinc sulfide (FIG. 10B) optics 900 with the design parameters provided in Table 2. Is. In the plot, the initial position of the optical element 900 is assumed to be end cap 505 to 25 mm. As shown, in both cases the BPP of the beam can be increased to about 4 to about 12 through displacement of the optics 900 by only about 30 mm (eg, about 28 mm to about 32 mm). The slope of this change in BPP as a function of displacement may be modified via a change in the numerical aperture of the fiber output at the end cap 505. The beam profile at a distance of 50 mm from the optical element 900 to the fiber end cap 505 is also a graph of its irradiance as a function of the position with respect to the 50 mm spacing between the optical element 900 and the end cap 505 in FIGS. 10A and 10B. Shown in.

11A-11C, as shown with respect to the optical element 600 in FIG. 6A, at a distance of 40 mm of the end cap 505, at different centered distances (0 mm, 2 mm, and 4 mm) for the optical element 900. The beam profile is shown. FIG. 11D is a graph of irradiance as a function of position for the beam profile depicted in FIG. 11C, clearly showing the two-peak nature of the intensity of the beam profile. In various embodiments, the variation in BPP at different off-center positions of the optical element 900 is about zero, even while the irradiance as a function of the position across the beam profile changes.

Embodiments of the present invention utilize optical elements to produce an annular beam shape. Embodiments of the present invention are characterized by one or more optical elements comprising, and essentially consisting of, or consisting of an axicon lens. As is known in the art, an axicon lens is a lens having at least one conical surface, such a lens for imaging a point source in a line compartment along the optical axis. It may be used. The conical surface of rotational motion can be mixed with light from a point source located on the axis of rotational motion by reflection, refraction, or both. Embodiments of the present invention are a double positive (ie, double convex) axicon lens 1200 and a double negative (ie) between the fiber end cap 505 and the collimating lens 510, as shown in FIG. 12A. , Double concave) Utilizing a combination of axicon lenses 1210, the beam size in the workpiece can be varied using this lens system. As shown, the lenses 1200, 1210 are separated in the beam path by a gap distance of 1220. θ1 and θ2 are the tilt variables of the conical surface that define the maximum droop (h1 and h2) and separation of the annular beam ring from the center of the beam spot, as graphically depicted in FIGS. 12B and 12C. In various embodiments of the invention, one or both conical surfaces of lenses 1200, 1210 have a smooth edge and a radius of curvature of less than about 5 μm.

FIG. 13 is a graph illustrating control of the BPP of a laser delivery system as a function of the clearance distance 1220 between two axicon lenses 1200, 1210. As shown in FIG. 13, a variation of about 7 mm at a gap distance of 1220 results in a BPP increase of 4-12, demonstrating the wide range of BPP control enabled by such embodiments of the present invention. The beam profile as a function of the clearance distance 1220 between the lenses 1200, 1210 is shown in FIG. 14, and the clearance distances are listed in millimeters. As shown, the adjustment of the gap distance 1220 can transform a beam profile with a single peak into one with two, three or more peaks. FIG. 15 depicts a similar beam profile when two axicon lenses 1200, 1210 are laterally offset by 4 mm in the beam path and separated by the listed clearance distances 1220 (gap distances are: , Listed in millimeters).

Embodiments of the present invention include, include, or consist essentially of a phase plate having one planar surface and an opposing surface thereof, and at least a portion of which is curved into a convex or concave surface. It features an optical element. FIG. 16A depicts a partial beam delivery system featuring two such plates 1600, 1610 separated by a gap Z. As shown, the plate 1600 is separated from the fiber end cap 505 by a distance S. 16B and 16C depict plates 1600, 1610 in more detail. As shown, the plates 1600, 1610 have an outer diameter D, and the convex / concave portions of its surface have an inner diameter d that defines the maximum droop h (in combination with R detailed below). .. The thickness of the plate at its outer peripheral boundary (ie, the thickness between the planar portions of its opposing surfaces) is represented by H, and the radius of curvature of the convex / concave portions is represented by R. As depicted in FIGS. 16B and 16C, plates 1600, 1610 have substantially the same H, D, d, and R, but various embodiments of the invention are one or more of their parameters. It features a pair of plates, one having a partially concave surface and one having a partially convex surface, which are different in one.

Table 3 provides exemplary design values for exemplary optical elements 1200, 1210 comprising, consisting essentially of, or consisting of two different materials, namely fused silica and zinc sulfide.

16D and 16E are optimized so that the inner diameters d of the plates 1600, 1610 according to the embodiments of the present invention maximize the output BPP of the laser delivery system as a function of the distance S from the fiber end cap 505. Depict what can be done. FIG. 16D is a graph of BPP as a function of inner diameter d for plates 1600, 1610, having a distance S 40 mm, a gap distance Z 10 mm, and a radius of curvature R 500. As shown, the resulting BPP is maximized at an inner diameter d of about 5 mm. The BPP is substantially independent of changes in the gap distance Z and the radius of curvature R. FIG. 16E is a graph of the optimized inner diameter d (ie, the inner diameter d that maximizes the output BPP) as a function of the distance S between the end cap 505 and the plate 1600. As shown, the optimized inner diameter d may be selected to maximize the BPP of the output beam as a function of distance S.

FIG. 16F is a graph of BPP at different gap distances Z between plates 1600, 1610 with the design parameters provided in Table 3 (using the design parameters in Table 3, fused silica and zinc sulfide plates 1600, 1610). Both provide the same result). In the plot, the distance S to the end cap 505 is assumed to be 40 mm. As shown, the BPP of the beam can be increased to about 4 to about 12 through modification of the gap Z between plates 1600, 1610 of only about 9 mm. Various beam profiles of the output beam as a function of the gap Z (in mm) are illustrated in FIG. 16G as a graph of its irradiance as a function of position. As shown, as the beam BPP increases, the beam shape changes from one with a single peak to one with a wider multi-peak irradiance profile.

Optical elements according to embodiments of the present invention may also include, and essentially consist of, or consist of a meniscus lens. The geometric design for the optical element 1700 according to such an embodiment is graphically depicted in FIG. 17A. As shown, in various embodiments, one surface of the optical element 1700 is curved in a convex shape over substantially the entire surface, while the opposing surface is curved in a concave shape over a portion of the surface, with an inner diameter d. Define. The optical element 1700 may be utilized as an optical element 520 and / or an optical element 525 within the delivery system 500. As shown, the optical element 1700 has an outer diameter D, an inner diameter d, a thickness H, a maximum hanging h1 of a convex curved surface, and a maximum hanging h2 of a partially concave curved surface. You may. The radius of curvature R, which can be substantially identical for both surfaces of the optical element 1700, defines the maximum droop h1 and h2 as well as the resulting separation of the annular beam ring from the center of the beam spot.

Table 4 provides exemplary design values for the exemplary optical element 1700, comprising, consisting of, or consisting of two different materials, namely fused silica and zinc sulfide.

FIG. 17B is a graph of BPP at different distances from the fiber end cap 505 to the exemplary fused silica optical element 1700 with the design parameters provided in Table 4. In the plot, the initial position of optical element 1700 is assumed to be end cap 505 to 25 mm. As shown, the BPP of the beam can be increased to about 4 to about 12 via displacement of the optics 1700 by only about 24 mm. The beam profile at a distance of 46 mm from the optical element 1700 to the fiber end cap 505 is also shown in FIG. 17B as a graph of irradiance as a function of position for the 46 mm spacing between the optical element 1700 and the end cap 505. Shown.

The laser beam delivery system according to embodiments of the present invention may also utilize various lens arrangements to form a larger and more dispersed input beam for BPP variation as a function of optical element movement. FIG. 18A depicts a portion of a laser delivery system 1800 incorporating a mobile optical element 1805 for BPP variation and a triple collimator to increase the divergence of the laser beam. As shown, the triple collimator increases the divergence of the beam from angle α to angle β. In various embodiments, the ratio of β to α is about 2 to about 1.5, for example about 1.74. As described in more detail below, this increased divergence allows for better control of the BPP with less movement of the optical element 1805. In various embodiments, the optical element 1805 comprises any one or more of the optical element 600, the optical element 900, the optical element 1700, the phase plate 1600/1610, or the axicon lenses 1200, 1210. In essence, or consists of it.

The triple collimator for increasing beam divergence according to an embodiment of the present invention may consist of various combinations of lenses. FIG. 18A illustrates one such embodiment, including a plano concave lens 1810, a meniscus lens 1815 (eg, a positive meniscus lens), and a plano convex lens 1820. In various embodiments of the invention, the optical element 1805 is arranged in the beam path between the plano-concave lens 1810 and the meniscus lens 1815. In other embodiments, the optical element 1805 may be located in the beam path between the meniscus lens 1815 and the plano-convex lens 1820 or even optically downstream of the plano-convex lens 1820.

FIG. 18B is exemplary with the design parameters provided in Table 1 from the fiber end cap 505 when used within the laser beam delivery system 1800 in combination with a triple collimator for increased beam divergence. FIG. 5 is a graph of BPP at different distances to the fused silica optical element 600. In the plot, the initial position of the optical element 600 is assumed to be end cap 505 to 25 mm. As shown, the BPP of the beam is only about 16 mm displacement of the optics 600, i.e. less than about twice the displacement (ie, better) compared to the beam delivery system lacking the triple collimator of FIG. 18A. Control) can be increased to about 4 to about 12 (see FIG. 7A). The beam profile at a distance of 21 mm from the optical element 600 to the fiber end cap 505 is also shown in FIG. 18B.

FIG. 18C is exemplary with the design parameters provided in Table 4 from the fiber end cap 505 when used within the laser beam delivery system 1800 in combination with a triple collimator for increased beam divergence. FIG. 5 is a graph of BPP at different distances to fused silica optical element 1700. In the plot, the initial position of optical element 1700 is assumed to be end cap 505 to 25 mm. As shown, the BPP of the beam is a displacement of the optical element 600 of only about 12 mm, i.e. less than about twice the displacement (ie, better) compared to the beam delivery system lacking the triple collimator of FIG. 18A. Control) can be increased to about 4 to about 12 (see FIG. 17B). The beam profile at a distance of 17.5 mm from the optical element 1700 to the fiber end cap 505 is also shown in FIG. 18C.

FIG. 18D is a schematic of a partial laser beam delivery system 1800 incorporating the aforementioned pair of phase plate optical elements 1600, 1610 separated in the beam path by a gap distance Z. FIG. 18E is an exemplary molten silica optical element 1600, 1610 with the design parameters provided in Table 3 when used within a laser beam delivery system 1800 in combination with a triple collimator for increased beam divergence. It is a graph of BPP about the different gap spacing Z of. In the plot, the position of the optical element 1600 is assumed to be 25 mm from the end cap 505. As shown, the BPP of the beam increases the clearance Z between the optical elements 1600, 1610 by only about 3 mm, ie about 3 compared to the beam delivery system lacking the triple collimator of FIG. 18A. It can be increased to about 4 to about 12 through less than double the displacement (ie, better control) (see Figure 16F). The beam profile at a gap distance of 3 mm between the optical elements 1600, 1610 is also shown in FIG. 18C.

The laser system and laser delivery system according to embodiments of the present invention, detailed herein, may be utilized within and / or with the WBC laser system. Specifically, in various embodiments of the invention, the multi-wavelength output beam of the WBC laser system is due to variations in BPP, beam shape, and / or polarization, as detailed herein. It may be used as an input beam for a laser beam delivery system. FIG. 19 illustrates an exemplary WBC laser system 1900 utilizing one or more lasers 1905. In the embodiment of FIG. 19, the laser 1905 features a diode bar having four beam emitters emitting beams 1910 (see magnified input FIG. 1915), but embodiments of the invention are in any number of individuals. A diode bar or a diode or diode bar in a two-dimensional array or stack may be utilized. In FIG. 1915, each beam 1910 is represented by a line, where the length or longer dimension of the line represents the slow divergence dimension of the beam and the height or shorter dimension represents the fast divergence dimension. Collimating optics 1920 may be used to collimate each beam 1910 along a high speed dimension. Deformation optics 1925, including, or essentially capable of containing one or more cylindrical or spherical lenses and / or mirrors, are used to combine each beam 1910 along the WBC direction 1930. Transforming optics 1925 then includes, or essentially consists of a dispersion element 1935 (eg, a reflection or transmission diffraction grating, a dispersion prism, a grinding (prism / grating), a transmission grating, or an Echelle grating) of the combined beam. The beams overlapped and combined on top are then transmitted onto the output coupler 1940 as a single output profile. The output coupler 1940 then transmits the combined beam 1945 onto the output front view 1950, as shown. The output coupler 1940 is typically partially reflective and acts as a common front facet for all laser elements within the external cavity system 1900. The external cavity is a lasing system in which the secondary mirror is displaced by a distance away from the emission aperture or facets of each laser emitter. In some embodiments, additional optics are installed between the emission aperture or facet and the output coupler or partially reflective surface. The output beam 1945 is therefore a multi-wavelength beam (combining the wavelengths of the individual beams 1910) and may be utilized as an input beam within the laser beam delivery system detailed herein and / or. It may be coupled in an optical fiber.

FIG. 20 depicts a laser system 2000 with a variable shape output beam utilized according to various embodiments of the present invention. As shown, the laser system 2000 may include a laser source 2010 (eg, the WBC laser system 1900 forms an output beam of multiple wavelengths) coupled to the optical fiber 2020. At the distal end of the optical fiber 2020 is a processing head or laser beam delivery system 2030. The processing head 2030 includes, or may consist essentially of, all or part of the components of the laser beam delivery system 500 described above, for example. For example, the processing head 2030 may incorporate and / or respond to a controller (eg, controller 540) that controls the output beam shape at focus 2040 on or near the surface of the workpiece. In various embodiments, as detailed herein, the processing heads 2030 are shaped and / or movable relative to each other to form an output laser beam with a variable output beam shape. It may include, or essentially consist of, various optical elements. FIG. 21 depicts a series of different output beam shapes that can be formed by the laser system 2000 according to an embodiment of the present invention. As shown, the output beam shape is highly focused, depending on the control voltage applied within the processing head 2030 (eg, via a controller to control the position of one or more optics within it). From the spot beam to a larger, diffused and unfocused spot, the annular beam. Also, as shown in FIG. 21, the BPP of the beam can also change as the beam shape changes.

In various embodiments, the laser system 2000 includes a controller (eg, controller 540, as described above) and / or a positioning system (eg, positioning system 315). The controller controls the operation of the laser system (ie, activates the laser and controls beam parameters such as intensity and / or output beam shape as needed during processing). The controller may also operate the positioning system. The positioning system may be any controllable optical system, mechanical system, or optical mechanical system for directing the beam through the processing path along the 2D or 3D workpiece. During processing, the controller allows the laser beam to traverse the processing path along the workpiece and / or at a specific point on the workpiece on which the laser output beam should be processed (eg, the position for welding). The positioning system and the laser system 2000 may be operated so that they can be positioned at. The processing path and / or one or more processing points may be provided by the user and stored onboard or in remote memory, which also includes parameters related to the type of processing (cutting, welding, etc.). The beam parameters (for example, the output beam shape) necessary for performing the processing may be stored. In this regard, the local or remote database may maintain a library of materials and thicknesses that the laser system will process, depending on the user's choice of material parameters (material type, thickness, etc.). May query the database to get the corresponding parameter values.

As deeply understood in plotting and scanning techniques, the required relative motion between the output beam and the workpiece used optical deflection of the beam with a movable mirror, gantry, feed screw, or other arrangement. It may be produced by the physical movement of the laser and / or the mechanical arrangement for moving the workpiece rather than (or in addition to) the beam. In some embodiments, the controller may receive feedback from the feedback unit regarding the beam position and / or the processing effectiveness of the beam with respect to the workpiece, which will be connected to a suitable monitoring sensor. In response to the signal from the feedback unit, the controller modifies the path, position, BPP, and / or shape of the beam.

In addition, the laser system may incorporate one or more systems for detecting the thickness of the workpiece and / or the height of features on it. For example, the laser system is as detailed in US Patent Application No. 14 / 676,070 filed April 1, 2015, the entire disclosure of which is incorporated herein by reference. A system (or component thereof) for measuring the depth of interference of the workpiece may be incorporated. Such depth or thickness information controls the output beam shape by a controller, eg, according to the records in the database corresponding to the type of material being processed, to process the workpiece (eg, cutting or welding). It may be used for optimization.

22A and 22B depict exemplary cutting scenarios according to embodiments of the present invention. In various embodiments of the invention, the laser system 2000 makes cuts of different depths and / or different sizes on the workpiece 2200 and / or cuts of consistent size within the workpiece 2200 with variable thickness. Used for. As shown, the output beam shape has a highly focused spot due to shallow cutting and is forced by a thicker area on the workpiece 2200 and / or a change in angle between the processing head 2030 and the workpiece 2200. Even if it is gradually or substantially abruptly varied to have an unfocused spot and / or an annular shape (and / or a spot with two or more distinctly different intensity peaks) for deeper cutting. Good. For example, as shown in FIG. 22A, the output beam may strike the workpiece 2200 at an angle approximately perpendicular to the surface of the workpiece 2200, and the output beam may be all or part of the thickness of the workpiece 2200. It may have the shape of a highly focused spot to make a relatively shallow cut through. Also, as shown in FIG. 22A, the shape of the beam is increased in order to make larger width cuts into the workpiece 2200 and / or through the workpiece 2200 along the output beam direction. As such, when the angle between the output beam and the surface 2200 of the workpiece is modified (eg, reduced), it may be modified into an unfocused spot or an annular shape.

In various embodiments, as shown in FIG. 22B, the angle of the processing head 2030 (and thus the output beam) is the topology, thickness of the workpiece 2200 during the relative motion between the beam and the workpiece 2200. And / or as the surface angle fluctuates, it can be kept constant (eg, approximately vertical) and the controller is presented to the processing head 2030 at various processing points or across processing paths, the effective thickness of the workpiece 2200. The beam shape is controlled according to (ie, the depth of cut required to cut through or within the workpiece 2200 to a specified distance). For example, the thickness of the workpiece 2200 presented to the processing head 2030 on the left side of FIG. 22B is larger than that on the right side of FIG. 22B, for example due to the surface topology, and the beam shape is adjusted accordingly. .. Such an arrangement eliminates the need for the processing head 2030 and / or the output beam to be repositioned to present a consistent angle between the beam and the workpiece surface. Therefore, the complex robot and / or other equipment and associated costs and complexity for repositioning the angle of the processing head can be avoided.

In various embodiments of the invention, a laser system is utilized to weld one or more workpieces while minimizing or substantially eliminating the need to scan the output beam over the surface of the workpiece. To. 23A-23D depict an exemplary welding sequence according to an embodiment of the present invention. As shown, the output beam shape 2300 has a larger area during spot welding to weld the two workpieces 2310 and 2320 together without the need for relative motion between the output beam and the workpiece. It varies from an annular shape (FIG. 23A) to a smaller ring shape (FIG. 23B), a large focusing spot (FIG. 23C), and a smaller area focusing spot (FIG. 23D). Thus, a uniform weld larger than the spot size 2300 in FIG. 23D (and / or at least as large as the outer boundary of the spot size 2300 in FIG. 23A) does not scan the beam along its surface and the two workpieces. It is formed between pieces 2310 and 2320. In various embodiments, the controller may vary the output power and / or BPP of the beam during the welding process, in addition to varying the shape of the output beam. For example, the output power of a highly focused beam shape can be reduced to substantially match the output power of a more defocused and / or annular beam, facilitating the formation of a spatially uniform weld. Thus, a large, uniform single weld is produced on the workpiece simply by modifying the beam shape (and in some embodiments, the beam power) and is produced over multiple smaller pieces over the same area. The need to form spot welds (as well as the need to move the workpiece relative to the beam with each weld) can be eliminated. Although FIGS. 23A-23D depict an exemplary spot welding process, embodiments of the present invention include other processing techniques and types of welding, such as lap welding and spot welding. In addition, the various welding steps using the different beam shapes depicted in FIGS. 23A-23D may be performed in any order according to embodiments of the present invention. Although FIGS. 23A-23D depict a series of four different beam shapes used for welding, embodiments of the present invention exceed two, three, or four when welding workpieces. Different beam shapes may be used.

The terms and expressions used herein are used as a descriptive point of view and exclude any equivalent of the features illustrated and described or any portion thereof in the use of such terms and expressions. Recognize that various modifications are possible within the scope of the claimed invention.

Claims (14)

A method of processing a workpiece, said method:
A relative motion is generated between the laser output beam and the surface of the workpiece to define a processing path, and the thickness of the workpiece along a direction parallel to the laser output beam is the said. The laser output beam varies along the processing path and physically modifies the surface of the workpiece along at least a portion of the processing path.
In the meantime, a method comprising modifying the shape of the laser output beam based, at least in part, on the thickness of the workpiece along a direction parallel to the laser output beam. The shape of the laser output beam, said as the thickness of the laser output beam and the workpiece along a direction parallel increases, the sera varied between the focused spot and the ring-shaped, the method according to claim 1 .. Claim that the thickness of the workpiece along a direction parallel to the laser output beam varies, at least in part, due to changes in the angle between the laser output beam and the surface of the workpiece. The method according to 1. The method of claim 1, wherein the shape of the laser output beam is modified while maintaining a substantially constant angle between the laser output beam and the surface of the workpiece. The first aspect of the present invention further comprises measuring the thickness of the workpiece along a direction parallel to the laser output beam during the relative motion between the laser output beam and the surface of the workpiece. the method of. The method of claim 1, wherein the shape of the laser output beam is modified based on the composition of the workpiece. The method according to claim 1, wherein the laser output beam is composed of a plurality of wavelengths. A system for processing workpieces, said system
A beam emitter for emitting a laser output beam,
A positioning device for varying the position of the laser output beam with respect to the workpiece, and
Means for modifying the shape of the laser output beam and
A controller coupled to the positioning device and the shape-modifying means, which (i) operates the beam emitter and passes the laser output beam through a path across at least a portion of the workpiece. move Te, the surface physically altered, along (ii) the path, at least in part, based on the thickness of the workpiece along the laser output beam in a direction parallel, the laser A system with a controller that modifies the shape of the output beam. The beam emitter comprises a processing head, the laser output beam is emitted from the processing head , and the shape-modifying means include (i) one or more optical elements in the processing head and (ii) the processing head. 8. The system of claim 8, comprising a second controller for modifying the position of at least one of the optical elements in the device. The system of claim 8, wherein the controller is configured to vary the output power of the beam emitter along the path. The system according to claim 8, wherein the controller is configured to vary the shape of the laser output beam based on the composition of the workpiece. 8. The system of claim 8, further comprising a database comprising a plurality of records, each of the plurality of records relating a laser output beam shape to a workpiece parameter. 12. The system of claim 12, wherein the workpiece parameter comprises at least one of a workpiece thickness and a workpiece composition. The beam emitter
A beam source that emits multiple discrete input beams and
Focusing optics for focusing the plurality of input beams on the dispersion element,
A dispersion element for receiving the focused beam and dispersing the received focused beam,
A partially reflected output coupler, the partially reflected output coupler receives the dispersed beam, transmits a part of the dispersed beam through it as the laser output beam, and the dispersed beam. 8. The system of claim 8, wherein the laser output beam comprises a partial reflection output coupler, which is positioned to reflect a second portion of the laser output towards the dispersion element.