Assembly and method for cutting a vitreous body with a laser

Abstract

Disclosed are cutting assemblies and methods for cutting a glass body having an end face at a desired angle greater than 0 degrees. The assembly includes a laser device for emitting a laser beam, a rotating device, and a positioning fixture. The rotating device has a head that rotates about a central axis normal to the laser beam. The positioning fixture is operatively mounted to the head and axially centered along the central axis, and is also rotatably driven by the rotating device. The positioning fixture has a taper that supports the glass body transverse to the central axis and at a predetermined angle relative to the central axis. When the glass body is exposed to the laser beam, rotation of the positioning fixture about the central axis cuts the end face of the glass body at the desired angle due to the glass body being supported transverse to the central axis.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 055,307, filed July 22, 2020, and U.S. Provisional Patent Application No. 63 / 073,705, filed September 2, 2020, both of which are incorporated herein by reference. background Invention Field

[0003] The present invention relates to components and methods for cutting or slicing glass bodies (such as rods, capillaries, or optical fibers), and more specifically, but not exclusively, to components for angular cutting or slicing of cylindrical glass bodies using laser cutting or slicing.

[0004] 2. Description of the prior art

[0005] Various techniques are known for cutting or slicing optical fibers to obtain optical-grade surfaces. Some techniques require mechanical scoring, followed by torsional fracture, and then mechanical polishing or grinding to eliminate the surface roughness, chatter, and cracks caused by the mechanical scoring. Other techniques, such as laser processing under controlled optical conditions (as disclosed in U.S. Patent 7,142,741B2), can achieve optical properties similar to mechanical polishing techniques. Both techniques have their advantages and disadvantages, and depending on the specific application, one method may be preferred over the other.

[0006] Since the early 2000s, laser processing of optical fibers has become the industry standard; however, mechanical polishing remains the superior method for processing optical fibers due to its low entry cost and versatility. Historically, a drawback of mechanically polishing fibers is the need to completely remove surface deformation caused by mechanical patterning, which typically requires lengthy and expensive polishing steps. Additional disadvantages include the inability to polish fibers to precise axial dimensions, the inability to align stress members with polarization-maintaining fibers at specified angles, and increased processing costs associated with achieving non-standard surface angles (i.e., 0° or 8°).

[0007] However, recently, with the influx of high-power transmissions required by 5G, autonomous vehicle sensors, and military weapons, silica deposits embedded in micro-abrasions found on the surface of optical fibers from conventional polishing techniques have been found to be highly absorbent and disrupt light transmission, producing undesirable back reflections and beam scattering. When these damages are present, device failure (optical fiber or active device) eventually occurs. For this reason, laser processing of conventional optical fibers used in these applications is gaining significant momentum; however, such laser processing of large-diameter glass bodies still has drawbacks.

[0008] Current laser processing methods are well-suited for conventional optical fibers, particularly those with a combined core / cladding diameter of 125 μm or less. However, laser processing becomes problematic for fibers or other glassy structures with a combined core / cladding diameter greater than 125 μm due to the energy difference between the incident and emitted beams. This incident / exit effect creates a undulating surface that impairs light transmission, produces uncontrollable back reflections, and introduces beam skew and a non-Gaussian energy distribution into the transmitted beam. During angled cutting of the fiber, surface undulations are further exacerbated, as the incident / exit effect is amplified by the increased cutting length along the bevel. Invention Overview

[0010] This invention provides a cutting assembly for cutting a glass body having an end face at a desired angle greater than 0 degrees and with reduced light scattering or absorption damage. The assembly includes: a laser device for emitting a laser beam; a rotating device; and a positioning fixture. The rotating device has a head that rotates about a central axis orthogonal to the laser beam. The positioning fixture is operably mounted to the head and axially centered along the central axis, and is also rotatably driven by the rotating device. The positioning fixture has a tapered surface transverse to the central axis and supports the glass body at a predetermined angle relative to the central axis. When the glass body is exposed to the laser beam, the rotation of the positioning fixture about the central axis cuts the end face of the glass body at a desired angle because the glass body is supported transversely to the central axis.

[0011] This invention further provides a method for cutting a glass body using a cutting assembly. The cutting assembly includes: a laser device for emitting a laser beam; a rotating device; and a positioning fixture. The method includes the following steps: aligning and positioning the rotating device and the positioning fixture along a central axis orthogonal to the laser beam, and mounting the positioning fixture to the head of the rotating device while supporting the glass body along a conical surface of the positioning fixture. The conical surface extends transversely to the central axis at a predetermined angle. Next, the positioning fixture and the head of the rotating device rotate about the central axis while the glass body is supported at the predetermined angle, such that the laser beam cuts the end face of the glass body at a desired angle corresponding to the predetermined angle.

[0012] This invention offers numerous advantages over existing components and methods. First, it provides end faces virtually free of surface undulations and damage, allowing for the processing of glass without the light scattering or absorption damage associated with mechanical polishing. Therefore, when cutting according to this invention, the end faces of the glass do not exhibit undesirable incident / exit effects. Another advantage of this invention is the ability to rapidly interchange multiple different positioning fixtures at varying predetermined angles on a rotating device while maintaining the precision of laser cutting at the exact desired angle. Brief description of the attached diagram

[0014] Other advantages of the invention will readily be understood, as they become better apparent when considered in conjunction with the accompanying drawings and by referring to the following detailed description, in which:

[0015] Figure 1 This is a perspective view of a cutting assembly for cutting glass bodies (such as rods, capillaries, or optical fibers) according to the invention of this subject matter, the cutting assembly having a laser device and a rotating device;

[0016] Figure 2 It is an exploded perspective view of the rotating device and positioning fixture used for cutting glass.

[0017] Figure 3 It is a close-up perspective view of the positioning fixture attached to the rotating device;

[0018] Figure 4 This is a close-up image of the positioning fixture supporting the glass body during rotation and laser beam cutting;

[0019] Figure 5 This is a close-up image of a positioning fixture used for cutting flat surfaces on glass.

[0020] Figure 6A This is a perspective view of a positioning fixture according to one embodiment of the invention.

[0021] Figure 6B yes Figure 6A A cross-sectional view of the positioning fixture shown;

[0022] Figure 6C yes Figure 6A End view of the positioning fixture shown;

[0023] Figure 7 It is a close-up image of a vitreous body with angled ends;

[0024] Figure 8A This is a perspective view of a positioning clamp according to another embodiment of the invention in accordance with this subject matter;

[0025] Figure 8B yes Figure 8A A cross-sectional view of the positioning fixture shown;

[0026] Figure 8C yes Figure 8A End view of the positioning fixture shown;

[0027] Figures 9A-9B yes Figure 8A A schematic diagram of the positioning fixture shown;

[0028] Figure 9C yes Figure 8A A schematic diagram of the positioning fixture at discrete points rotating around the central axis;

[0029] Figure 10 It is a close-up of the vitreous body at a specific rotation angle;

[0030] Figure 11 shows various cutting angles on different glass bodies formed according to the invention of this subject;

[0031] Figure 12-14 This is a schematic diagram of one embodiment of the cutting assembly invented according to this subject matter;

[0032] Figure 15A It is a photograph of a 1mm glass rod with a cut angle of 2.71 degrees;

[0033] Figure 15B It is a photograph of a 1mm glass rod with a cut angle of 8.36 degrees; and

[0034] Figures 16A-16C are perspective photographs of glass bodies cut using existing techniques. Invention Details

[0036] This invention generally relates to an assembly 100 and method for cutting a glass body 102 to a desired angle using a laser beam 104. The glass body 102 includes, but is not limited to, a glass rod, capillary, ferrule, tube, and optical fiber. Typically, the glass body 102 is cylindrical and is particularly suitable for bevel applications and optical applications (high power and other applications sensitive to back reflection, light scattering, beam deflection, and light transmission). The assembly 100 can be used for angles greater than 0 degrees and will produce an angle on the end face 106 of the glass body 102 without lenses or tapers.

[0037] refer to Figure 1 A perspective view of one embodiment of the cutting assembly 100 for cutting glass body 102. Figure 1Generally, it includes a laser device 108 and a rotating device 110. The glass body 102 may comprise a glass rod, a glass capillary, or an optical fiber. The glass body 102 has a diameter of at least 125 μm, which is considered large by those skilled in the art when compared to conventional telecommunications-grade optical fibers. The glass body 102 extends along a longitudinal central axis C between a first end 112 and a second end 114. The first end 112 of the glass body 102 presents an end face 106 to be cut or finished. Depending on the specific application, the glass body 102 can be of any desired length. The glass body 102 can be hollow or solid. One embodiment of the glass body 102 is referred to as a glass rod, preferably a solid glass rod. In another embodiment, when the glass body 102 is a glass capillary, the glass capillary may be hollow. In yet another embodiment, when the glass body 102 is an optical fiber, the optical fiber includes at least one core formed of glass material. Optionally, the optical fiber may include a cladding (not shown) surrounding the core and an outer layer (not shown) surrounding the core. Furthermore, the optical fiber can contain multiple cores. This invention can be practiced with any of the various types of glass bodies described herein, but is particularly suitable for large-diameter solid glass rods exceeding 125 μm.

[0038] Laser device 108 emits a laser beam 104, preferably a carbon dioxide laser beam 104 with a wavelength of 10.6 μm. It should be understood that other types of laser devices 108 with different beam shapes and wavelengths can be used with this invention. For example, laser device 108 can be a quantum cascade laser, an ultraviolet excimer laser, a semiconductor laser, etc., and it can emit a laser beam 104 with wavelengths between 0.2 and 11 μm. Laser device 108 may include a focusing system 116 to guide and manipulate the laser beam 104 to a first end 112 of the glass body 102.

[0039] refer to Figure 2 The rotating device 110 includes a head 118 that rotates about a central axis C orthogonal to the laser beam 104 emitted by the laser device 108. A positioning fixture 122 is operably mounted to the head 118 and axially centered along the central axis C. The positioning fixture 122 is rotatably driven by the rotating device 110 about the central axis C. The positioning fixture 122 has a conical surface 106 that is transverse to the central axis C and supports the glass body 102 at a predetermined angle θ relative to the central axis C. Since the glass body 102 is supported transversely to the central axis C, when the laser beam 104 is guided to the glass body 102, the rotation of the positioning fixture 122 about the central axis C cuts the end face 106 of the glass body 102 at a desired angle.

[0040] refer to Figure 3The positioning clamp 122 has an outer surface 126, a front surface 128, and a back surface 130. The back surface 130 defines a retainer 132 for operably mounting to the head 118. (Reference) Figure 6B and 8B The fastener 132 is further shown to be threaded. As an example, the fastener 132 may be an M6 or 0.25-32 thread.

[0041] Reference Figure 1 and 2 The extender 134 is operatively mounted between the positioning clamp 122 and the head 118. The extender 134 operatively secures the positioning clamp 122 to the rotating device 110. Furthermore, the extender 134 can also serve as an auxiliary support for the glass body 102 in applications requiring rotation of large objects about a central axis C, as discussed further below. The extender 134 may also be threaded at one or both ends, serving as an external or internal threaded connector. It should be understood that the extender 134 can be used with certain types of glass bodies 102 and not with other types of glass bodies 102.

[0042] This invention may also include an adapter 136 operatively mounted between the extender 134 and the head 118. The adapter 136 may also be threaded at one or both ends for mounting between the extender 134 and the head 118. It should be understood that the adapter 136 can be used with certain types of glass bodies 102 and not with other types of glass bodies 102. Furthermore, in some embodiments, the extender 134 or the adapter 136 may be omitted without departing from this invention.

[0043] Referring to the glass body 102 shown in the figure, the glass body 102 extends between a first end 112 and a second end 114. The tapered surface 106 of the positioning clamp 122 supports the glass body 102 such that the first end 112 and the second end 114 can be held transversely to the central axis C of the rotating device 110, and (if present) an extender 134 and an adapter 136. Figure 1 and 2 In the embodiment shown, the positioning device, the extender 134, and the adapter 136 are connected together and centered along the central axis C.

[0044] Figure 3 The central axis C along the extender 134, adapter 136, and positioning clamp 122 is shown. The glass body 102 is presented at a predetermined angle drawn along the axis L. The predetermined angle between C and L is defined as θ, which is controllable by the conical surface 106.

[0045] Specifically, refer to Figure 4The image shows a close-up perspective view of the cutting instrument. In this embodiment, the positioning clamp 122 has an extension 134 integrated therein, and the positioning clamp 122 rotates about a central axis C. The laser beam 104 cuts the glass body 102 at a first end 112 point, producing a lost fragment S, which is then discarded. The end face 106 of the glass body 102 is then transformed into an angled geometry that matches the desired angle.

[0046] Figure 5 A positioning clamp 122 is shown having an inner hole 138 extending between a front face 128 and a back face 130, wherein the inner hole 138 is axially centered along a central axis C. In various embodiments, the positioning clamp 122 may have a tapered shape. A tapered surface 106 is defined as a channel 140 extending between the front face 128 and the back face 130 in an outer surface 126. The tapered surface 106 has a predetermined angle from greater than 0 degrees to 45 degrees. In this embodiment, the central axis C is the same as the axis L of the glass body 102. Therefore, the glass body 102 rotates about C and L, producing a flat 0° surface 106 geometry. This configuration allows the positioning clamp 122 to produce two different types of surface geometries on the surface 106, namely a surface 106 with a desired angle and a flat geometry. One advantage of this subject matter invention is that various positioning clamps 122 can be made with different predetermined angles. Therefore, when different angles are required on different glass bodies 102, a positioning clamp 122 with a suitable tapered surface 106 can be selected. This allows for quick replacement of the positioning clamp 122 while maintaining precise cutting of the glass body 102.

[0047] Figure 6A yes Figure 5 Perspective view of the positioning fixture 122 shown. Figure 6B It is a cross-sectional view and Figure 6C yes Figure 5 The positioning fixture 122 is shown as an end view. The positioning fixture 122 has a channel 140 that extends downward along the outer surface 126 to define a conical surface 106 at a predetermined angle θ. The channel 140 ensures the elimination of complex angles during the cutting operation. The predetermined angle controls the cutting during rotation and cutting operations.

[0048] Figure 7 This is a close-up schematic diagram of a glass body 102 formed using a positioning fixture 122 according to the present invention, and the glass body is exposed to a laser beam 104 during rotation. The end face 106 of the glass body 102 has a desired angle of 2 degrees.

[0049] Now for reference Figure 8AThis illustrates another embodiment of the positioning clamp 122'. The positioning clamp 122' includes a front face 128, a back face 130, an outer surface 126, and an inner bore 138; however, in this embodiment, the positioning clamp 122' is defined by a conical surface 106 within the inner bore 138. An insert 142, sized to fit within the inner bore 138, is inserted into the inner bore 138. The conical surface 106 is defined between the insert 142 and the inner bore 138, and a glass body 102 is fixed therebetween at a predetermined angle. Specifically, the insert 142 has an outer surface 144 inclined at a predetermined angle to define the conical surface 106. The outer surface 144 may also include a channel 140'. In such embodiments, multiple different inserts 142 with different predetermined angles, such as 2 degrees, 5 degrees, etc., can be used. Optionally, the inner bore 138 has an inclined surface 146 at a predetermined angle to define the conical surface 106. The inclined surface 146 may also include a channel 140'. Similarly, different positioning jigs 122 with an inner hole 138 having different predetermined angles that can be easily changed while maintaining cutting accuracy can be prepared. The conical surface 106 can be defined with a predetermined angle from greater than 0 degrees or at least 0.5 degrees to 45 degrees.

[0050] Figure 8B yes Figure 8A The cross-sectional view of the positioning fixture 122' shown is shown. Figure 8C yes Figure 8A The image shows an end view of the positioning clamp 122'. In this embodiment, the glass body 102 is located within the inner bore 138 and secured in place by the insert 142. The glass body 102 is easy to insert and remove and does not require tunneling because the glass body 102 is secured by the wedging force of the tapered insert 142. The insert 142 may be disposed within the locator and mate with at least a portion of the inner bore 138 to secure the glass body 102. In one embodiment, the inner bore 138 may include a channel 140' to receive the glass body 102. The insert 142 holds the glass body 102 within the channel 140'. Optionally, the channel 140 may be formed within the insert 142. In yet another embodiment, the glass body 102 may be held in place by means of adhesive or the like so that it can be removed after being cut. Figure 8C The diameter and thickness of the positioning clamp 122', the inner hole 138, and the insert 142 are shown.

[0051] Figure 9A and 9B The diagram illustrates the positioning fixture 122' in two positions as it rotates about its central axis C. Figure 9A In the middle, one position of the vitreous body 102 is shown at -180 degrees, and in Figure 9B In the middle, another position of the vitreous body 102 is shown at +180 degrees. Figure 9CThe glass rod is shown rotating at 90-degree intervals with the positioning clamp 122', with the two positions indicated by dashed lines. In this embodiment, the cone angle is 2 degrees.

[0052] Figure 10 This is a close-up of the glass body 102 in its -180° and +180° positions within the rotation of the positioning fixture 122'. The ends 112 and 114 of the glass body 102 are precisely mirror images of each other during rotation, allowing the laser beam 104 to cut at the desired angle. The predetermined angle θ corresponds to the desired angle

[0053] Figure 11 illustrates the versatility of the glass rod, which can be achieved by the cutting assembly 100 of the present invention, which utilizes positioning clamps 122, 122' with different predetermined angles, allowing for an infinite array of cutting angles for the glass body 102. Figure 11 shows a glass body 102 having a first end 112 with a desired angle from 0 degrees to any desired angle. The angles illustrated in Figure 11 are relative to the axis L of the glass body 102. The axis L has a predetermined angle defined by a conical surface 124. Those skilled in the art will denote a 90-degree angle as a 0-degree cut. Examples of 87.5, 82, and 70 degrees will represent 2.5, 8, and 20-degree cuts as understood by those skilled in the art.

[0054] refer to Figure 12-14 This illustrates one embodiment of a cutting assembly 100 invented according to this subject matter. Specifically, Figure 12 A DC power supply 120, which is connected to and supplies power to the rotating device 110, is shown, as is well known to those skilled in the art. Figure 13 The optical path of laser head 118 is shown. Figure 14 The camera 148, laser device 108, and other optical devices are shown.

[0055] refer to Figures 15A-15B This shows the use of Figure 12-14 A close-up photograph of a 1mm glass rod effectively cut by the cutting assembly 100 shown. Specifically, in Figure 15A In Figure 16, the end of the glass rod has been cut to an angle of 8.36 degrees, with a target value of 8.0 degrees. In Figure 16B, the end of the glass rod has been cut to an angle of 2.71 degrees, with a target value of 2.5 degrees.

[0056] For illustrative purposes and to demonstrate the importance of the invention, rotating the glass body 102 during the laser cutting process, without the embodiments of the invention, will produce a conical or tapered surface 106 as shown in photographs 16A-16C. These methods generally cannot produce a flat angle greater than 0 degrees without these types of damage and irregularities. While rotating the glass body 102 about its axis L during laser processing of large-diameter optical fibers can reduce incident / exit effects and produce a surface suitable for optical-grade transmission, this method is only suitable for flat (0°) cuts. Figures 16A-16C show the glass body 102, which is rotated only about its axis L orthogonal to the laser beam 104 and obtains an unacceptable conical or tapered geometry.

[0057] The invention has been described in an illustrative manner, and it should be understood that the terminology used is intended to describe the nature of the words rather than to limit their nature. It will now be apparent to those skilled in the art that many modifications and variations of the invention are possible in accordance with the foregoing teachings. Therefore, it should be understood that the invention can be practiced in ways other than those specifically described.

Claims

1. A cutting assembly for cutting a glass body at a desired angle greater than 0 degrees and with reduced light scattering or absorption damage, the glass body having an end face, the assembly comprising a laser device for emitting a laser beam; a rotating device comprising a head that rotates about a central axis normal to the laser beam; a positioning fixture operably mounted to the head and axially centered along the central axis, the positioning fixture being rotatably driven by the rotating device; and wherein the positioning fixture has a tapered surface transverse to the central axis and supporting the glass body at a predetermined angle relative to the central axis, and wherein rotation of the positioning fixture about the central axis cuts the end face of the glass body at the desired angle due to the glass body being supported transverse to the central axis.

2. The cutting assembly of claim 1, wherein the positioning fixture has an outer surface, a front face, and a back face, the back face defining a fastener for operably mounting to the head.

3. The cutting assembly of claim 2, wherein the fastener is further defined as being threaded.

4. The cutting assembly of claim 2, further comprising an extender operably mounted between the positioning fixture and the head.

5. The cutting assembly of claim 4, further comprising an adapter operably mounted between the extender and the head.

6. The cutting assembly of claim 5, wherein the head is threaded.

7. The cutting assembly of claim 6, wherein the adapter is threaded, and wherein the extender is threaded for mounting to one another.

8. The cutting assembly of claim 2, wherein the positioning fixture further comprises an inner bore extending between the front face and the back face, the inner bore being axially centered along the central axis.

9. The cutting assembly of claim 8, wherein the tapered surface is defined as a channel in the outer surface extending between the front face and the back face.

10. The cutting assembly of claim 9, wherein the tapered surface has the predetermined angle from greater than 0 degrees to 45 degrees.

11. The cutting assembly of claim 8, further comprising an insert sized within the inner bore, and the tapered surface is defined within the inner bore to secure the glass body at the predetermined angle.

12. The cutting assembly of claim 11, wherein the insert further comprises an outer surface that is inclined at the predetermined angle to define the tapered surface.

13. The cutting assembly of claim 11, wherein the inner bore further comprises an inclined surface at the predetermined angle to define the tapered surface.

14. The cutting assembly of claim 11, wherein the tapered surface has the predetermined angle from 0.5 degrees to 45 degrees.

15. A method of cutting a glass body with a cutting assembly, the cutting assembly comprising a laser device for emitting a laser beam, a rotating device having a head, and a positioning fixture, the method comprising the steps of: ​ positioning the rotation device and the positioning fixture centrally aligned along a central axis of the laser beam; mounting the positioning fixture to a head of the rotation device; supporting the glass body along a taper of the positioning fixture, the taper extending transverse to the central axis at a predetermined angle; rotating the positioning fixture and the head of the rotation device about the central axis while the glass body is supported at the predetermined angle such that the laser beam cuts an end face of the glass body at a desired angle corresponding to the predetermined angle.

16. The method of claim 15, wherein the step of supporting the glass body with the taper is further defined as positioning the glass body in a channel of an outer surface of the positioning fixture, the channel defining the predetermined angle.

17. The method of claim 15, wherein the step of supporting the glass body with the taper is further defined as positioning the glass body within an inner bore of the positioning fixture defining the predetermined angle.

18. The method of claim 17, further comprising the step of inserting an insert into the inner bore to define the predetermined angle.

19. The method of claim 15, wherein the taper has the predetermined angle from greater than 0 degrees to 45 degrees.

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