Protective Multi-Window Cartridge Assembly

Abstract

A device and method are provided that includes a multi-window cartridge assembly that can be used to protect an optical assembly in a laser head, the multi-window cartridge assembly including: a window mount configured to support and rotate a transparent window about a rotation axis, an aperture configured to allow passage of a processing laser beam along an optical axis that passes through a processing position on the transparent window, a housing for enclosing the transparent window and at least a portion of the window mount, the housing configured to form at least a portion of the aperture, and a rotation mechanism configured to engage at least a portion of the window mount to rotate the transparent window about the rotation axis to a rotation position that includes the processing position.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims priority to U.S. Provisional Application No. 63 / 435,623, entitled "PROTECTIVE MULTIWINDOW CARTRIDGE ASSEMBLY," filed December 28, 2022, the contents of which are incorporated herein by reference in their entirety.

[0002] FIELD OF THE INVENTION The present invention relates to a protective window assembly, and more particularly to a protective window assembly for use in combination with a laser processing head. [Background technology]

[0003] Contamination is a frequent problem on the inner surface of laser windows used in material laser processing heads. It takes the form of particulates that accumulate on the window surface and interfere with laser beam transmission. Contamination typically occurs during installation and gradually builds up on the laser optics. Radiation emitted from the processing laser burns off the contaminants, destroying the optics within the head, necessitating their removal and replacement. Protective windows must be removed and replaced frequently and at short intervals, accounting for as much as 90% of downtime experienced during material processing operations, according to some estimates. Furthermore, the act of removing and replacing the window exposes the laser optics to contaminants. Summary of the Invention

[0004] Aspects and embodiments are directed to multi-window cartridge assemblies and uses thereof.

[0005] According to one exemplary embodiment, a multi-window cartridge assembly is provided that includes a window mount configured to support and rotate a transparent window about a rotation axis; an opening configured to allow passage of a processing laser beam along an optical axis passing through a processing position on the transparent window; a housing for enclosing the transparent window and at least a portion of the window mount, the housing configured to form at least a portion of the opening; and a rotation mechanism configured to engage with at least a portion of the window mount to rotate the transparent window about the rotation axis to a rotation position that includes a processing position.

[0006] In one example, the window mount is further configured to support the transparent window at an angle.

[0007] In one example, the multi-window cartridge assembly further includes a position indicator configured to indicate the rotational position of the transparent window.

[0008] In one example, the optical axis is parallel to the axis of rotation.

[0009] In one example, the multi-window cartridge further includes a frame assembly configured to hold the transparent window within the housing.

[0010] In one example, the window mount is a first window mount and the assembly further includes a second window mount configured to support and rotate a second transparent window.

[0011] In one example, the transparent window is coupled to at least a portion of an optical assembly that optically interacts with the processing laser beam. In a further example, the optical assembly is configured to focus the processing laser beam. In a further example, the optical assembly is configured to collimate the processing laser beam.

[0012] In one example, the window mount is configured to support two or more transparent windows.

[0013] According to another exemplary embodiment, a laser system for performing a material modification process on a workpiece is provided, the laser system including: a laser source configured to generate a processing laser beam; and a laser head configured to receive the processing laser beam from the laser source. The laser head includes focusing optics configured to focus the processing laser beam, and a multi-window cartridge assembly disposed downstream from the focusing optics. The multi-window cartridge assembly includes: a window mount configured to support and rotate a transparent window about a rotation axis; an aperture configured to allow passage of the processing laser beam along an optical axis passing through a processing position on the transparent window; a housing for enclosing at least a portion of the transparent window and the window mount, the housing configured to form at least a portion of the aperture; and a rotation mechanism configured to engage at least a portion of the window mount to rotate the transparent window about the rotation axis to a rotation position including the processing position.

[0014] In one example, the laser head further includes a contamination sensor configured to detect contamination on at least one flat surface of the transparent window. In a further example, the contamination sensor is configured as a visible light photodiode. In a further example, the laser system further includes a controller coupled to the contamination sensor, the controller configured to receive contamination measurements from the contamination sensor, compare the contamination measurements with a predetermined contamination threshold, and, in response to the comparison, send a notification to a display device. In one example, the controller is configured to send a notification when the contamination measurements exceed the predetermined contamination threshold. In another example, the laser head further includes a temperature sensor, the controller configured to receive temperature measurements from the temperature sensor, compare the temperature measurements with a predetermined temperature threshold, and, in response to the comparison, perform at least one of sending a notification to a display device and controlling the laser source. In one example, the controller is configured to send a notification and / or control the laser source when the temperature measurements exceed the predetermined temperature threshold.

[0015] In one example, the multi-window cartridge assembly is a first multi-window cartridge assembly, and the laser head further includes a collimator configured to collimate the processing laser beam, the collimator being positioned upstream of the focusing optics, and a second multi-window cartridge assembly disposed upstream of the collimator.

[0016] In one example, the window mount of the multi-window cartridge assembly is configured to support the transparent window at an angle.

[0017] In one example, the multi-window cartridge assembly further includes a position indicator configured to indicate a rotational position of the transparent window. In a further example, the laser head further includes a housing configured with an opening that exposes at least a portion of the rotation mechanism and the position indicator. In one example, the laser head further includes a cover door attached to the housing and configured to cover the opening.

[0018] In one example, the laser head further includes a housing configured to seal the multi-window cartridge within the housing.

[0019] In one example, the laser source is configured as a fiber laser, and the processing laser beam is delivered to the laser head by an optical fiber.

[0020] According to another exemplary embodiment, a method for protecting an optical assembly included in a laser processing head is provided, the method including the steps of: providing a multi-window cartridge assembly containing a transparent window configured to protect the optical assembly; exposing a first rotational processing position on the transparent window to an environment containing a contaminant; measuring the intensity of scattered radiation from a plane of the transparent window; comparing the measured intensity with a predetermined contamination threshold; and providing a notification in response to the comparison result when the measured intensity exceeds the predetermined contamination threshold.

[0021] In one example, the method further includes rotating the transparent window to a second rotational processing position if the measured intensity exceeds a predetermined contamination threshold. In a further example, the transparent window is provided with N rotational processing positions, and the method further includes the steps of exposing, measuring, comparing, and rotating until each of the N rotational processing positions has been exposed.

[0022] In one example, the optics assembly is configured to focus the processing laser beam through the laser head and the first rotary processing location.

[0023] In one example, the optics assembly is configured to collimate a processing laser beam passing through the laser head and the first rotary processing location.

[0024] In one example, the method further includes measuring a temperature near the transparent window, comparing the measured temperature to a predetermined temperature threshold, and, in response to the comparison, performing at least one of providing a notification and controlling a laser source that generates a processing laser beam passing through the laser head when the measured temperature exceeds the predetermined temperature threshold. In a further example, the method further includes rotating the transparent window to a second rotational processing position when the measured temperature exceeds the predetermined temperature threshold.

[0025] In one example, the method further includes providing a laser processing head.

[0026] According to another exemplary embodiment, a laser processing head is provided that includes focusing optics configured to focus a processing laser beam and a multi-window cartridge assembly disposed downstream of the focusing optics, the multi-window cartridge assembly including: a window mount configured to support and rotate a transparent window about a rotation axis, an opening configured to allow passage of the processing laser beam along an optical axis passing through a processing position on the transparent window, a housing for enclosing the transparent window and at least a portion of the window mount, the housing configured to form at least a portion of the opening, and a rotation mechanism configured to engage at least a portion of the window mount to rotate the transparent window about the rotation axis to a rotation position that includes the processing position.

[0027] In one example, the multi-window cartridge assembly is a first multi-window cartridge assembly, and the laser processing head further includes a collimator configured to collimate the processing laser beam, the collimator being positioned upstream of the focusing optics, and a second multi-window cartridge assembly disposed upstream of the collimator.

[0028] In one example, the laser processing head further includes at least one of a contamination sensor configured to detect contamination on at least one planar surface of the transparent window and a temperature sensor configured to measure a temperature in the vicinity of the transparent window.

[0029] In one example, the window mount of the multi-window cartridge assembly is configured to support the transparent window at an angle.

[0030] In one example, the multi-window cartridge assembly further includes a position indicator configured to indicate the rotational position of the transparent window.

[0031] In one example, the laser processing head further includes a housing configured with an opening that exposes at least a portion of the rotation mechanism and the position indicator, hi a further example, the laser processing head further includes a cover door attached to the housing and configured to cover the opening.

[0032] In one example, the laser processing head further includes a housing configured to seal the multi-window cartridge within the housing.

[0033] In one example, the processing laser beam is generated by a fiber laser source that is fed to a laser processing head by an optical fiber.

[0034] Still other aspects, embodiments, and advantages of these exemplary aspects and embodiments are discussed in detail below. Furthermore, it should be understood that the foregoing information and the following detailed description are merely illustrative examples of various aspects and embodiments and are intended to provide an overview or framework for understanding the nature and characteristics of the claimed aspects and embodiments. The embodiments disclosed herein may be combined with other embodiments, and references to "one embodiment," "one example," "some embodiments," "some examples," "an alternative embodiment," "various embodiments," "one embodiment," "at least one embodiment," "this embodiment and other embodiments," "a particular embodiment," etc. are not necessarily mutually exclusive and are intended to indicate that a particular described feature, structure, or characteristic may be included in at least one embodiment. Appearances of such terms herein do not necessarily all refer to the same embodiment.

[0035] Various aspects of at least one embodiment are discussed below with reference to the accompanying drawings, which are not intended to be drawn to scale. The drawings are included to provide illustration and a further understanding of various aspects and embodiments, and are incorporated into and constitute a part of this specification, but are not intended as a definition of the limitations of any particular embodiment. The drawings, together with the remainder of the specification, serve to explain the principles and operation of the aspects and embodiments described and claimed herein. In the drawings, each identical or nearly identical component shown in the various drawings is represented by a like numeral. It is to be clarified that not every component is labeled in every figure. The drawings are as follows: [Brief explanation of the drawings]

[0036] [Figure 1] FIG. 1 is a schematic perspective view of an example of a multi-window cartridge assembly according to an aspect of the present invention. [Figure 1A]2 is a first example of a cross-sectional view of the multi-window cartridge assembly of FIG. 1 taken along line "A" in a vertical plane. [Figure 1B] 2 is a cross-sectional top view of the multi-window cartridge assembly of FIG. 1 taken along a horizontal plane through the center of the assembly. [Figure 2] 1 is a perspective view of an example of a transparent window showing various rotational processing positions in accordance with an aspect of the present invention; [Figure 3] 2 is a second example of a cross-sectional view of the multi-window cartridge assembly of FIG. 1 taken along line "A" in a vertical plane. [Figure 4] 1 is a schematic cross-sectional view of an example laser head configured with at least one multi-window cartridge assembly according to an embodiment of the present invention. [Figure 5] FIG. 1 is a schematic perspective view of an example laser head configured with at least one multi-window cartridge assembly according to an embodiment of the present invention. [Figure 6] FIG. 1 is a simplified block diagram of a laser system according to an aspect of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0037] Aspects and embodiments are directed to a multi-window cartridge assembly and its use in combination with a laser processing head. The multi-window cartridge assembly addresses the above-mentioned problems associated with frequent replacement of protective windows used in laser heads that function to protect optics, such as focusing optics, from contamination. For example, the disclosed multi-window cartridge assembly is configured to rotate the protective window through multiple rotational positions, one of which is a processing position. This allows the protective window to be rotated so that a "clean" location is the processing position, allowing for less frequent window replacement.

[0038] 1 is a schematic perspective view illustrating one non-limiting example of a multi-window cartridge assembly 100 (also referred to herein simply as a "cartridge assembly" or "assembly") according to at least one embodiment. Multi-window cartridge assembly 100 includes a window mount 106 (see FIGS. 1A and 1B), an opening 105, a housing 102, and a rotation mechanism 108.

[0039] FIG. 1A is a cross-sectional view of the multi-window cartridge assembly 100 of FIG. 1 taken along line "A" in a vertical plane, and FIG. 1B is a top cross-sectional view of the multi-window cartridge assembly 100 of FIG. 1 taken along a horizontal plane through the center of the assembly. A window mount 106 (also referred to herein as a "bushing") is configured to support the transparent window 104 and rotate it about an axis of rotation 101. In some embodiments, the window mount 106 is attached to at least one or more peripheral edges of the transparent window 104 and can rotate 360° about the axis of rotation 101, thereby allowing the transparent window 104 to rotate 360°. The window mount 106 is also configured to maintain or otherwise support the transparent window 104 at an angle, as can be seen by angle α in FIG. 1A. By having the transparent window 104 at an angle, back reflections are prevented so that the processing light is not reflected directly back through the optics (e.g., fibers, collimating lenses, and / or focusing lenses, described in more detail below). In some embodiments, the window is mounted at an angle in the range of 0.5 degrees to 10 degrees. In some embodiments, the transparent window 104 is not configured at an angle.

[0040] Aperture 105 is configured to allow passage of processing laser beam 142 (see FIGS. 4 and 6 ) along optical axis 103. Aperture 105 extends through the overall height (H) dimension of multi-window cartridge assembly 100. Processing laser beam 142 is generated by laser source 160 (see FIG. 6 ) and passes through aperture 105 along optical axis 103. Optical axis 103 and rotation axis 101 are parallel to one another. As used herein, the term “upstream” refers to the direction toward laser source 160, and the term “downstream” refers to the direction toward workpiece 170, where processing laser beam 142 interacts with the material of workpiece 170. Transparent window 104 (also referred to herein simply as “window”) extends within and across aperture 105, as seen in FIG. 1A . 1B, the area of ​​transparent window 104 that extends across aperture 105 and is exposed to processing laser beam 142, contamination sources, and / or other heat sources is referred to as processing location 124 (also referred to herein as one of the rotational processing locations). It will be understood that optical axis 103 also passes through processing location 124.

[0041] The housing 102 of the multi-window cartridge assembly 100 is configured to surround at least a portion of the transparent window 104 and the window mount 106 and form at least a portion of an opening. The housing 102 functions, in part, to protect an unused portion of the transparent window 104 (described in more detail below). The housing 102 can also add to the modular aspect of the multi-window cartridge assembly 100. According to at least one embodiment, the housing 102 can be removed from the laser head (described in more detail below) and replaced with a new cartridge assembly, or in other cases, the housing 102 can be removed and a new transparent window 104 can be installed in the assembly 100.

[0042] The rotation mechanism 108 of the multi-window cartridge assembly 100 is configured to engage at least a portion of the window mount 106 to rotate the transparent window 104 about a rotation axis 101. The rotation axis 101 passes through the approximate center of the transparent window 104. The rotation mechanism 108 rotates the transparent window 104 to rotational positions, including a processing position 124. This can be seen in the schematic diagram of the transparent window 104 shown in FIG. 2, where rotational position 124a is the “current” processing position (and intersects with the optical axis 103) and is shown as 124 in FIGS. 1A and 1B. In this example, rotational position 124a represents a processing position exposed to contamination, while rotational positions 124b-124h are “clean” or “fresh” rotational positions protected by the housing 102. When the current processing position becomes contaminated to or beyond a certain threshold (described below), the window 104 is rotated to a new rotational processing position. In this example, window 104 is rotated in the direction of the arrow in FIG. 2 so that rotational position 124b moves into aperture 105 and aligns with optical axis 103, exposing the "clean" surface of transparent window 104 to processing radiation and contamination. This process is repeated until all of the rotational positions are contaminated and a new window is required. While the example in FIG. 2 shows eight rotational positions, it should be understood that fewer (i.e., at least two) or more (e.g., ten) rotational positions are within the scope of this disclosure. The number of positions is a function of one or more factors, including the size of window 104 and the size of aperture 105.

[0043] According to at least one embodiment, the rotation mechanism 108 includes any one or more components, such as a support structure, that allow the window mount 106 to rotate about the rotation axis 101. For example, with reference to FIG. 1 , a user may rotate the transparent window 104 by engaging the transparent window 104 with the rotation mechanism 108 and pushing the rotation mechanism 108 in the direction of the arrow shown. In some embodiments, the window mount 106 is exposed so that a user can engage and rotate the window 104.

[0044] According to at least one embodiment, the multi-window cartridge assembly 100 also includes a position indicator 120 configured to indicate the rotational position of the transparent window 104. This feature allows a user to know how many "clean" positions are left on the window and, in some embodiments, also provides an indication as to when the window 104 has been fully rotated to a new "clean" position. A non-limiting example of the position indicator 120 shown in FIG. 1 includes a series of grooves or notches located on the exterior of the housing 102 that indicate the number of rotational positions 124 and provide a reference point for a pointer or indicator; in this example, it is contemplated to have a lip or marker formed on the sidewall of the window mount 106 that aligns with the notches or grooves when the rotational positions are fully engaged. It should be understood that the position indicator may be any feature or set of features that communicates to the user the rotational position of the transparent window 104 and / or communicates to the user when a certain rotational position has been engaged (i.e., rotated to the point where a completely clean surface is exposed within the opening 105 and no portions of the previous rotational position that are now contaminated or otherwise unusable / endangered remain exposed within the opening 105).

[0045] FIG. 3 is another example cross-sectional view of the multi-window cartridge assembly 100 of FIG. 1 taken along line "A" in a vertical plane, showing one non-limiting example of a frame assembly 107 (shown in FIG. 3 as 107a, 107b, and 107c). The frame assembly 107 is configured to hold the transparent window 104 within the housing 102. The frame assembly 107 includes several components that provide kinematic constraints. For example, the upper and lower frames 107a and 107b hold the window by friction, and the screw 107c is used to apply force to the upper and lower frames 107a and 107b. The housing 102 is configured with upper and lower frames and a slot 122 for the window mount 106, and the force is transmitted through the upper frame 107a, the window mount 106, the transparent window 104, and the lower frame 107b to the bottom of the slot 122. Other components (not shown in FIG. 3 ) may also be included, such as ball and groove components, springs, O-rings, gaskets, flanges, etc. It should be understood that the exemplary frame assembly 107 shown in FIG. 3 is one non-limiting example, and that the frame assembly may comprise any one of several different component configurations that prevent the transparent window 104 from moving during the laser processing operation and allow the window to rotate without causing damage to the window's surface.

[0046] According to certain aspects, a processing laser head and laser system for performing a material modification process on a workpiece are disclosed. Figure 4 is a cross-sectional view of an example laser head 140, Figure 5 is a perspective view of laser head 140, and Figure 6 is a simplified block diagram of a non-limiting example laser system 130 including laser head 140. Laser system 130 includes a laser source 160 configured to generate a processing laser beam 142. Laser head 140 is configured to receive processing laser beam 142 from laser source 160.

[0047] Laser source 160 may be any one of several different types of laser sources, including solid-state, gas, fiber, and excimer laser radiation sources. According to one embodiment, laser source 160 is configured as a fiber laser, and processing laser beam 142 is delivered to the laser head by optical fiber 125, as shown in FIG. 6. Suitable fiber laser sources for practicing embodiments of the present disclosure are available from IPG Photonics (Marlborough, Massachusetts, USA). Laser beam 142 interacts with the material of workpiece 170 to perform a material modification process. Non-limiting examples of material modification processes include welding, cutting, drilling, brazing, annealing, soldering, and additive manufacturing.

[0048] The transparent window 104 functions to protect one or more optical assemblies within the laser head 140. The transparent window 104 includes at least one flat surface and is optically transparent to the processing laser beam 142. The transparent window 104 can be constructed from any one or more different materials, non-limiting examples of which include fused silica, tin selenide, tin sulfide, sapphire (Al2O3), calcium fluoride, magnesium fluoride, barium fluoride, sodium chloride, potassium bromide, glass materials, and the like. Additionally, one or more flat surfaces may be coated with an anti-reflective coating. Thus, the transparent window 104 is configured to maximize transmission over a specific wavelength range while minimizing reflection and absorption. According to at least one embodiment, the optical assembly protected by the transparent window is configured to focus the processing laser beam 142. According to another embodiment, the optical assembly is configured to collimate the processing laser beam 142.

[0049] In one embodiment, laser head 140 includes focusing optics 144 configured to focus processing laser beam 142. Depending on the desired application, processing laser beam 142 may be focused above, above, or below workpiece 170. Focusing optics 144 may include one or more lenses and / or other optical components, as will be understood by those skilled in the art. For example, focusing optics 144 may comprise one or more cylindrical lenses, one or more spherical lenses, and in some cases, may also include one or more spherical and / or cylindrical mirrors. As shown in FIGS. 4 and 6 , multi-window cartridge assembly 100b is disposed downstream from focusing optics 144. Transparent window 104b of multi-window cartridge assembly 100b functions to protect focusing optics 144 from splashes and debris during laser processing operations. Focusing optics 144 are typically expensive components and must be free of contamination to function optimally.

[0050] According to another embodiment, the laser head 140 includes a collimator 134 configured to collimate the processing laser beam 142. The collimator 134 is disposed upstream of the focusing optics 144. The collimator 134 includes one or more collimator lenses that collimate light from the delivery fiber 125. The delivery fiber 125 is attached to the laser head 140 using a fiber receiver 132. The multi-window cartridge assembly 100a is disposed upstream of the collimator 134. The transparent window 104a of the multi-window cartridge assembly 100a functions to protect the collimator 134 from various sources of contamination. For example, when the optical fiber 125 is initially positioned within the receiver 132, debris from the optical fiber 125 and / or the receiver 132 can be introduced onto the surface of the collimator 134, which can increase absorption on the lens and be detrimental to the function and operational life of one or more lenses. Additionally, contaminants may settle on other surfaces within the laser head, which may then flake off and deposit on the optics within the head, including the collimator 134. Therefore, the transparent window 104a of the multi-window cartridge assembly 100a protects the collimator 134 from these sources of contamination.

[0051] Referring now to FIG. 5 , according to one specific embodiment, the laser head 140 also includes a housing 146 configured with an opening 145 that exposes at least a portion of the multi-window cartridge assembly 100. For example, the opening 145 exposes at least a portion of the rotation mechanism 108 and the position indicator 120. The example shown in FIG. 5 has two such openings: opening 145a for the multi-window cartridge assembly 100a (associated with protecting the collimator 134) and opening 145b for the multi-window cartridge assembly 110b (associated with protecting the focusing optics 144). In a further aspect, the laser system also includes a cover door 110 attached to the housing 146 and configured to cover the opening 145. As shown in FIG. 5 , in this example, the cover door 110a covers the opening 145a, and the cover door 110b covers the opening 145b. Housing 146 also includes aperture 148 (see FIG. 4) or opening that allows processing laser beam 142 to pass therethrough and is aligned with optical axis 103, aperture 105a of multi-window cartridge assembly 100a, and aperture 105b of multi-window cartridge assembly 100b. Focusing optics 144 and collimator 134 extend within this aperture 148 in housing 146.

[0052] According to another embodiment, the laser head includes a housing (not shown) configured to seal the multi-window cartridge 100 therein. In such a configuration, the housing provides a gas-tight (or substantially gas-tight) enclosure with a hermetic closure. In this configuration, the actuator may be controlled by the controller 150, which actuates the rotation of the window mount and thus functions as the rotation mechanism. The controller 150 may also be configured to track how many "clean" rotation positions remain and send an alert to the user (e.g., via a display device) when all rotation positions on the window have been contaminated. This configuration may be used in applications where even less interaction (e.g., opening) with the laser head is desirable.

[0053] According to another aspect, the laser system 130 also includes a contamination sensor 136 configured to detect contamination on at least one planar surface of the transparent window 104. For example, contamination on the at least one planar surface generates scattered light (radiation), and the sensor 136 is configured to detect the scattered light (i.e., the intensity of the scattered radiation). According to some embodiments, the contamination sensor 136 is configured to perform contamination measurements on the planar surface of the window 104. FIG. 6 includes a contamination sensor 136a associated with monitoring the transparent window 104a protecting the collimator 134, and a contamination sensor 136b associated with monitoring the transparent window 104b protecting the focusing optics 144. In one embodiment, the contamination sensor 136a is positioned or otherwise arranged to monitor the top (upstream) surface of the transparent window 104a closest to one or more sources of contamination (e.g., the optical fiber 125 and the receiver 132). In another embodiment, the contamination sensor 136b is positioned or otherwise arranged to monitor the lower (downstream) surface of the transparent window 104b closest to one or more sources of contamination (e.g., the workpiece and the material modification process).

[0054] The laser system 130 also includes a controller 150 coupled to the contamination sensors 136 (e.g., contamination sensors 136a and 136b), e.g., the controller 150 providing feedback to a user regarding the contamination status when the contamination exceeds a threshold level. For example, in one embodiment, the controller 150 is configured to receive contamination measurements (i.e., measured intensities) from the contamination sensors 136, compare the contamination measurements to a predetermined contamination threshold, and send a notification to the display device 155 in response to the results of the comparison. According to one embodiment, the contamination sensors 136 are configured as visible light photodiodes. In some embodiments, the notification can indicate that the contamination measurements do not exceed the predetermined contamination threshold. According to a further aspect, the controller is configured to send a notification when the contamination measurements exceed the predetermined contamination threshold. The predetermined contamination threshold can be set by a user (and programmed into the controller 150). The user is also notified that the transparent window 104 is currently “dirty” via the display device 155 (e.g., an electronic device having a screen). When this occurs, the user can remove cover door 110 to access rotation mechanism 108 of multi-window cartridge assembly 100, use position indicator 120 to rotate rotation mechanism 108 to the next “clean position” (rotation position), and then replace cover door 110 onto housing 146 to cover opening 145. In certain embodiments with a fully enclosed laser head, controller 150 controls the actuator that rotates window 104 (e.g., automatically in response to measurements from sensors 136 and / or 138 or in response to input by a user). According to some embodiments, even without a fully enclosed laser head, controller 150 can control the actuator that rotates window 104. When all processing rotation positions have been used, multi-window cartridge assembly 100 can be removed and replaced with a new multi-window cartridge assembly.By some estimates, implementations of multi-window cartridge assemblies can reduce downtime by as much as 90%, and multi-window cartridge assemblies can be used continuously (without replacement) for as long as a year.

[0055] According to another embodiment, the laser system also includes a temperature sensor 138. The temperature sensor 138 is configured to monitor (i.e., measure) the temperature near the transparent window 104. Many laser processes implement the use of high-power lasers (e.g., at least 1 kW of power), which can generate heat within the laser head. Furthermore, if the optics become contaminated with particles or other debris (e.g., film), the contamination absorbs the laser radiation and generates heat. The more heat generated, the more contaminated the transparent window 104 is. Contamination on the transparent window 104 can be monitored by the temperature sensor 138 alone or in addition to the contamination sensor 136. In the non-limiting example shown in FIG. 6 , the temperature sensor 138a is positioned or otherwise disposed near the transparent window 104a, and the temperature sensor 138b is positioned near the transparent window 104b. The temperature sensors 138 are positioned such that temperature measurements are meaningful in determining the contamination level of the transparent window 104, as described in more detail below.

[0056] According to one embodiment, controller 150 is coupled to temperature sensor 138 and configured to receive temperature measurements from temperature sensor 138. In some embodiments, controller 150 is configured to compare the temperature measurements to a predetermined temperature threshold, which may be set by a user, and, in response to the comparison, to at least one of send a notification to display device 155 and control laser source 160. For example, the notification may relay to the user via display device 155 that the temperature is “OK” or has increased or decreased since the last measurement. In some embodiments, controller 150 is configured to send a notification to display device 155 and / or control laser source 160 when the temperature measurements exceed the predetermined temperature threshold. For example, when the temperature exceeds the threshold, a control signal may be sent to laser source 160 to reduce or turn off the power of laser source 160. This may prevent further heat buildup that could damage the optics within laser head 140. In some embodiments, when the temperature measurement exceeds a threshold, the user is notified (via the display device 155) and may initiate rotating the transparent window 104 to a new rotational position or replacing the cartridge assembly, as described above.

[0057] The contamination sensor 136 and / or the temperature sensor 138 may be configured to take measurements at periodic time intervals during the laser processing operation, or possibly continuously, and transmit the measurements to the controller 150, which then performs an evaluation of the measurements.

[0058] It should be understood that controller 150 may be a processing computer or computing device including a processing unit operably coupled to memory that stores control logic and other data, as will be understood by those skilled in the art. For example, controller 150 is configured to communicate with one or more components of laser system 130, including laser source 160, contamination sensors 136a and 136b, and temperature sensors 138a and 138b. Controller 150 may also be configured to communicate with components of multi-window cartridge assembly 100, such as rotation mechanism 108 or other actuation mechanisms as described above.

[0059] To implement a method according to aspects of the present disclosure, a multi-window cartridge assembly is used, as described above. According to some embodiments, a method for protecting an optical assembly included in a laser processing head includes providing a multi-window cartridge assembly containing a transparent window configured to protect the optical assembly. Such a multi-window cartridge assembly 100 is shown in the figures and discussed herein. The method also includes exposing a first rotational processing position (124) on the transparent window to an environment containing a contaminant. Referring to FIG. 2, processing position 124a is the first rotational processing position exposed to the contaminant environment. The method also includes measuring the intensity of scattered radiation from the plane of the transparent window. This can be achieved using contamination sensor 136, as described above. The method also includes comparing the measured intensity to a predetermined contamination threshold, as described above, and, in response to the comparison, providing a notification when the measured intensity exceeds the predetermined contamination threshold, as also described above. For example, a notification can be sent to a display device so that a user knows when the measured intensity exceeds the predetermined contamination threshold. The method may also include rotating the transparent window to a second rotational processing position if the measured intensity exceeds a predetermined contamination threshold. For example, the rotation mechanism 108 may be engaged by a user or an actuator that rotates the transparent window to the second rotational processing position (e.g., position 124b is rotated to the previous position 124a shown in FIG. 2). In some embodiments, the method also includes providing a transparent window with N rotational processing positions, and further includes exposing, measuring, comparing, and rotating until each of the N rotational processing positions has been exposed. For example, in FIG. 2, N=8, which is associated with rotational processing positions 124a-124h. In some embodiments, an optical system assembly is configured to focus the processing laser beam passing through the laser head and the first rotational processing position. Focusing optical system 144 is one such type of optical system assembly.In some embodiments, an optical system assembly is configured to collimate the processing laser beam passing through the laser head and the first rotary processing position. Collimator 134 is one such type of optical system assembly. In another embodiment, the method further includes measuring a temperature near the transparent window. This can be accomplished using temperature sensor 138, as described above. In addition, the method can include comparing the measured temperature to a predetermined temperature threshold and, in response to the comparison result, performing at least one of providing a notification and controlling a laser source generating the processing laser beam passing through the laser head when the measured temperature exceeds the predetermined temperature threshold. For example, if the measured temperature exceeds the predetermined temperature threshold, a notification can be sent to a display device or the laser source can have operating parameters adjusted (e.g., lower output power, turn off laser power) so that a user understands. The method also includes rotating the transparent window to a second rotary processing position when the measured temperature exceeds the predetermined temperature threshold, as described herein. In some embodiments, the method also includes providing a laser processing head. One non-limiting example of such a laser head is described herein and shown in FIGS.

[0060] According to another embodiment, window mount 104 is configured to support two or more transparent windows. For example, instead of a single piece of rotating transparent material, the window mount may be configured to hold multiple windows that can be rotated into opening 105 and exposed to processing laser beam 142. In one embodiment, multiple circular windows are arranged circumferentially on the window mount. Each window can be sized to accommodate the dimensions of opening 105 so that the transparent material extends across opening 105 when the window is rotated into place.

[0061] According to another embodiment, transparent window 104 is coupled to at least a portion of an optical assembly that optically interacts with processing laser beam 142. For example, a focusing assembly or a collimating assembly can be added as an accessory to the respective assembly and installed within the laser head. The assemblies can be provided with openings to access rotation mechanism 108, or the assemblies can be sealed within the laser head housing, as described above.

[0062] Aspects disclosed herein in accordance with the present invention are not limited in their application to the details of construction and the arrangements of components set forth in the following description or illustrated in the accompanying drawings. These aspects may incorporate other embodiments and may be practiced or carried out in various ways. Examples of specific implementations are provided herein for illustrative purposes only and are not intended to be limiting. In particular, acts, components, elements, and features described in connection with any one or more embodiments are not intended to be excluded from a similar role in any other embodiment.

[0063] Additionally, the phraseology and terminology used herein are for purposes of description and should not be considered limiting. Any reference herein to system and method examples, embodiments, components, elements, or acts in the singular may also encompass embodiments that include the plural, and any reference herein to any embodiment, component, element, or act in the plural may also encompass embodiments that include only the singular. References in the singular or plural are not intended to limit the disclosed systems or methods, their components, acts, or elements. The use herein of "including," "comprising," "having," "containing," "involving," and variations thereof, is meant to encompass the items listed thereafter and equivalents thereof, as well as additional items. References to "or" may be construed as inclusive, such that any term described using "or" may refer to one, more than one, and all of the described terms. Furthermore, if there is a discrepancy in term usage between this document and a document incorporated herein by reference, the term usage in the incorporated reference should be considered secondary to the usage in this document. In the event of any irreconcilable discrepancy, the term usage in this document shall prevail. Furthermore, titles or subtitles may be used herein for the convenience of the reader, and this shall not affect the scope of the invention.

[0064] Having thus described several aspects of at least one example, it should be understood that various alterations, modifications, and improvements will readily occur to those skilled in the art. For example, the examples disclosed herein may be used in other contexts. Such alterations, modifications, and improvements are intended to be part of this disclosure and are intended to be within the scope of the examples discussed herein. Accordingly, the foregoing description and drawings are by way of example only. [Explanation of symbols]

[0065] 100 multi-window cartridge assembly, 101 rotating shaft, 102 housing, 103 optical axis, 104 transparent window, 105 aperture, 106 window mount, 107 frame assembly, 108 rotation mechanism, 110 cover door, 120 position indicator, 124 processing position, 130 laser system, 134 collimator, 136 contamination sensor, 138 temperature sensor, 140 laser head, 142 processing laser beam, 144 focusing optics, 145 aperture, 146 housing, 150 controller, 155 display device, 160 laser source, 170 workpiece

Claims

1. 1. A multi-window cartridge assembly comprising: a window mount configured to support and rotate a transparent window about an axis of rotation; an aperture configured to pass a processing laser beam along an optical axis passing through a processing location on the transparent window; a housing for enclosing at least a portion of the transparent window and the window mount, the housing configured to define at least a portion of the opening; a rotation mechanism configured to engage at least a portion of the window mount to rotate the transparent window about the axis of rotation to a rotational position, the rotational position including the processing position; and A multi-window cartridge assembly comprising:

2. The multi-window cartridge assembly of claim 1 , wherein the window mount is further configured to support the transparent window at an angle.

3. The multi-window cartridge assembly of claim 1 , further comprising a position indicator configured to indicate the rotational position of the transparent window.

4. The multi-window cartridge assembly of claim 1 , wherein the optical axis is parallel to the axis of rotation.

5. The multi-window cartridge assembly of claim 1 , further comprising a frame assembly configured to retain the transparent window within the housing.

6. 10. The multi-window cartridge assembly of claim 1, wherein the window mount is a first window mount, the assembly further comprising a second window mount configured to support and rotate a second transparent window.

7. The multi-window cartridge assembly of claim 1 , wherein the transparent window is coupled to at least a portion of an optical assembly that optically interacts with the processing laser beam.

8. The multi-window cartridge assembly of claim 7 , wherein the optical assembly is configured to focus the processing laser beam.

9. The multi-window cartridge assembly of claim 7 , wherein the optical assembly is configured to collimate the processing laser beam.

10. The multi-window cartridge assembly of claim 1 , wherein the window mount is configured to support two or more transparent windows.

11. 1. A laser system for performing a material modification process on a workpiece, the laser system comprising: a laser source configured to generate a processing laser beam; a laser head configured to receive the processing laser beam from the laser source, the laser head comprising: focusing optics configured to focus the processing laser beam; a multi-window cartridge assembly disposed downstream of the focusing optical system, the multi-window cartridge assembly comprising: a window mount configured to support and rotate a transparent window about an axis of rotation; an aperture configured to pass the processing laser beam along the optical axis through a processing location on the transparent window; a housing for enclosing at least a portion of the transparent window and the window mount, the housing configured to define at least a portion of the opening; a rotation mechanism configured to engage at least a portion of the window mount to rotate the transparent window about the rotation axis to a rotational position, the rotational position including the processing position.

12. 12. The laser system of claim 11, wherein the laser head further comprises a contamination sensor configured to detect contamination on at least one planar surface of the transparent window.

13. 13. The laser system of claim 12, wherein the contamination sensor is configured as a visible light photodiode.

14. Further comprising a controller coupled to the contamination sensor, the controller comprising: receiving a pollution measurement from the pollution sensor; comparing said contamination measurement to a predetermined contamination threshold; 13. The laser system of claim 12, configured to send a notification to a display device in response to the comparison.

15. 15. The laser system of claim 14, wherein the controller is configured to send the notification when the contamination measurement exceeds the predetermined contamination threshold.

16. The laser head further includes a temperature sensor, and the controller receiving a temperature measurement from the temperature sensor; comparing the temperature measurement to a predetermined temperature threshold; In response to the comparison, sending a notification to the display device; and 12. The laser system of claim 11 configured to perform at least one of:

17. 17. The laser system of claim 16, wherein the controller is configured to send the notification and / or control the laser source when the temperature measurement exceeds the predetermined temperature threshold.

18. The multi-window cartridge assembly is a first multi-window cartridge assembly, and the laser head comprises: a collimator configured to collimate the processing laser beam, the collimator being positioned upstream of the focusing optics; a second multi-window cartridge assembly disposed upstream of the collimator; 12. The laser system of claim 11.

19. 12. The laser system of claim 11, wherein said window mount of said multi-window cartridge assembly is configured to support said transparent window at an angle.

20. 12. The laser system of claim 11, wherein said multi-window cartridge assembly further comprises a position indicator configured to indicate said rotational position of said transparent window.

21. 21. The laser system of claim 20, wherein the laser head further comprises a housing configured with an opening exposing the rotation mechanism and at least a portion of the position indicator.

22. 22. The laser system of claim 21, wherein the laser head further comprises a cover door attached to the housing and configured to cover the opening.

23. 12. The laser system of claim 11, wherein the laser head further comprises a housing configured to seal the multi-window cartridge therein.

24. 12. The laser system of claim 11, wherein the laser source is configured as a fiber laser and the processing laser beam is delivered to the laser head by an optical fiber.

25. 1. A method for protecting an optical assembly included in a laser processing head, comprising: providing a multi-window cartridge assembly containing transparent windows configured to protect the optical system assembly; exposing a first rotating location on the transparent window to an environment containing contaminants; measuring the intensity of scattered radiation from the plane of the transparent window; comparing the measured intensity with a predetermined contamination threshold; providing a notification in response to the comparison when the measured intensity exceeds the predetermined contamination threshold; A method comprising:

26. 26. The method of claim 25, further comprising rotating the transparent window to a second rotational processing position if the measured intensity exceeds the predetermined contamination threshold.

27. 27. The method of claim 26, wherein the transparent window is provided with N rotational machining positions, the method further comprising the steps of exposing, measuring, comparing, and rotating until each of the N rotational machining positions has been exposed.

28. 26. The method of claim 25, wherein the optics assembly is configured to focus a processing laser beam passing through the laser head and the first rotary processing location.

29. 26. The method of claim 25, wherein the optics assembly is configured to collimate a processing laser beam passing through the laser head and the first rotary processing location.

30. measuring the temperature adjacent the transparent window; comparing the measured temperature to a predetermined temperature threshold; In response to the comparison, performing at least one of providing a notification and controlling a laser source that generates a working laser beam passing through the laser head if the measured temperature exceeds the predetermined temperature threshold; 26. The method of claim 25, further comprising:

31. 31. The method of claim 30, further comprising rotating the transparent window to a second rotational processing position if the measured temperature exceeds the predetermined temperature threshold.

32. 26. The method of claim 25, further comprising the step of providing the laser processing head.

33. A laser processing head, a focusing optical system for focusing the processing laser beam; a multi-window cartridge assembly disposed downstream of the focusing optical system, the multi-window cartridge assembly comprising: a window mount configured to support and rotate a transparent window about an axis of rotation; an aperture configured to pass the processing laser beam along the optical axis through a processing location on the transparent window; a housing for enclosing at least a portion of the transparent window and the window mount, the housing configured to define at least a portion of the opening; a rotation mechanism configured to engage at least a portion of the window mount to rotate the transparent window about the rotation axis to a rotational position, the rotational position including the processing position.

34. The multi-window cartridge assembly is a first multi-window cartridge assembly, and the laser processing head includes: a collimator configured to collimate the processing laser beam, the collimator being positioned upstream of the focusing optics; a second multi-window cartridge assembly disposed upstream of the collimator; 34. The laser processing head of claim 33, further comprising:

35. 35. The laser processing head of claim 33 or claim 34, further comprising at least one of a contamination sensor configured to detect contamination on at least one planar surface of the transparent window and a temperature sensor configured to measure a temperature in the vicinity of the transparent window.

36. 35. The laser processing head of claim 33 or claim 34, wherein the window mount of the multi-window cartridge assembly is configured to support the transparent window at an angle.

37. 35. The laser processing head of claim 33 or claim 34, wherein the multi-window cartridge assembly further includes a position indicator configured to indicate a rotational position of the transparent window.

38. 35. The laser processing head of claim 33 or claim 34, further comprising a housing configured with an opening that exposes the rotation mechanism and at least a portion of the position indicator.

39. 35. The laser processing head of claim 33 or claim 34, further comprising a cover door attached to the housing and configured to cover the opening.

40. 35. A laser processing head according to claim 33 or claim 34, further comprising a housing configured to seal the multi-window cartridge therein.

41. 34. The laser processing head of claim 33, wherein the processing laser beam is generated by a fiber laser source supplied to the laser processing head by an optical fiber.

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