Optical relay system and methods of use and manufacture

Abstract

This invention discloses numerous specific examples of optical relay systems. In one specific example, a laser processing apparatus includes an optical relay system configured to correct beam placement errors by maintaining the optical path length of the laser energy beam between a first positioner and a scanning lens. In another specific example, the optical relay system may include a first lens, a second lens, and a zoom lens assembly disposed between the first and second lenses, wherein the zoom lens assembly includes a first lens group and a second lens group. The zoom lens assembly is movable relative to the first and second lenses (e.g., mounted on a positioner such as a motion stage). The distances between the lenses in the first lens group and the distances between the lenses in the second lens group may be fixed or variable.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 122,573, filed December 8, 2020, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0003] The specific examples described in this article typically relate to laser processing equipment, optical relay systems, their components, and the techniques for operating them. Background Technology

[0004] Laser processing systems or equipment are used in a wide variety of applications, including printed circuit board (PCB) machining, additive manufacturing, and the like. Many laser processing systems include a scanning lens for focusing a laser energy beam onto a workpiece and a positioner for moving the focused laser energy beam relative to some material to be processed. In some laser processing systems, the scanning lens is movable while the positioner remains stationary, so the optical path length between the scanning lens and the positioner can change depending on the movement of the scanning lens. This change in the optical path length causes the laser energy beam to rotate around a pivot point located outside the entrance pupil of the scanning lens (also referred to herein as the "scanning lens entrance pupil" or more simply as the "SLEP"). The position of the pivot point outside the SLEP can introduce telecentric errors, causing beam distortion at the workpiece and undesired beam shearing at the scanning lens entrance pupil. Summary of the Invention

[0005] A specific example of the present invention can be characterized as a laser processing apparatus comprising: a first positioner configured to deflect a laser energy beam around a pivot point; a scanning lens movable relative to the first positioner; and an optical relay system configured to relay the pivot point to the scanning lens in response to the movement of the scanning lens, wherein the scanning lens is movable relative to the optical relay system. The first positioner may be provided as an AOD system or a galvanometer lens system. The optical relay system is movable relative to the scanning lens and / or the first positioner. The optical relay system may include: an optical input; a first reflector having a first reflective surface, wherein the first reflector is configured to receive a laser energy beam propagating from the first positioner; an optical output; and a second reflector having a second reflective surface opposite to the first reflective surface, wherein the first and second reflective surfaces are configured to relay the laser energy beam received at the first reflector from the optical input to the optical output. The first and second reflective surfaces may be substantially parallel to each other. A first lens may be mounted at the optical input; and a second lens may be mounted at the optical output. A first positioner (e.g., an AOD system and a galvanometer mirror system) is movable relative to an optical relay system, and a linear motion stage is coupled to the first positioner, wherein the stage is operable to change the position of the first positioner relative to the optical relay system.

[0006] In another specific example, the optical relay system may include: a first lens configured and positioned to focus a laser energy beam within the optical relay system; and a second lens configured and positioned to focus a laser energy beam exiting the optical relay system, wherein the first and second lenses are configured to amplify the laser energy beam. The first lens may be configured to focus the laser energy beam at a point separate from the first and second reflective surfaces. A stage may be coupled to the optical relay system, wherein the stage is operable to change the position of the optical relay system relative to a scanning lens, a first positioner, or a combination thereof.

[0007] In another specific example, the laser processing equipment may further include a second positioner configured between the optical relay system and the scanning lens, wherein the second positioner may be a galvanometer, an AOD system, a fast control mirror, or a rotating polygonal mirror.

[0008] In another specific example, the optical relay system may include: a first lens; a second lens; and a zoom lens assembly disposed between the first and second lenses, wherein the zoom lens assembly includes a first lens group and a second lens group, and each of the first and second lens groups includes a plurality of lenses. The first and second lens groups are provided as telephoto doublets arranged symmetrically with respect to the lateral centerline of the zoom lens assembly. The zoom lens assembly is movable relative to at least one of the first and second lenses (e.g., mounted on a first locator, such as a motion stage). The first and second lenses may be provided as positive lenses, planar convex lenses, biconvex lenses, or positive concave-convex lenses, or any combination thereof. The distance between the lenses in the first lens group and the distance between the lenses in the second lens group may be fixed or variable. The first lens group may be mounted on a second locator (e.g., a motion stage) configured to adjust the distance between the lenses in the first lens group. The second lens group can be mounted on a third positioner (e.g., a motion stage), which is configured to adjust the distance between the lenses in the second lens group. Attached Figure Description

[0009] Figures 1 to 3 A schematic diagram illustrating the various spatial states of a laser processing system.

[0010] Figure 4 This illustration depicts a laser processing device based on a specific example.

[0011] Figure 5 and Figure 6 This demonstrates the different positional states of an optical relay system based on a specific example.

[0012] Figure 7A and Figure 7B This demonstrates different positional states of another specific example of an optical relay system. Figure 7A and Figure 7B In the image, the optical relay system is shown in a cross-sectional front view.

[0013] Figure 8 and Figure 9 This demonstrates different positional states of another specific example of an optical relay system.

[0014] Figure 10 and Figure 11 This demonstrates different positional states of another specific example of an optical relay system.

[0015] Figure 12 A view showing another specific example of an optical relay system.

[0016] Figures 13A to 13C exhibit Figure 12The different positional states of specific examples of optical relay systems shown in the figure. Detailed Implementation

[0017] Specific examples are described herein with reference to the accompanying drawings. Unless otherwise explicitly stated, the size, position, and any distances between components, features, elements, etc., in the drawings are not necessarily scaled, but rather enlarged for clarity. In the drawings, the same numbers refer to the same elements throughout. Therefore, the same or similar numbers may be described with reference to other drawings, even if these numbers are not mentioned or described in the corresponding drawings. Furthermore, elements not indicated by reference numbers may be described with reference to other drawings.

[0018] The terminology used herein is for the purpose of describing specific instances only and is not intended to be restrictive. Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art. As used herein, unless the context clearly indicates otherwise, the singular forms "a / an" and "the" are intended to include the plural forms as well. It should be understood that the term "comprises / comprising," when used in this specification, designates the presence of stated features, integrals, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or groups thereof. Unless otherwise specified, when describing a range of values, the range includes both the upper and lower limits of the range and any subranges therein. Unless otherwise indicated, terms such as "first," "second," etc., are used only to distinguish one element from another. For example, a node can be called the "first node", and similarly, another node can be called the "second node", or vice versa.

[0019] Unless otherwise indicated, the terms “about,” “approximately,” etc., mean quantities, sizes, formulas, parameters, and other quantities and characteristics that are not and need not be precise, but may be approximate and / or larger or smaller as needed, reflecting tolerances, conversion factors, rounding, measurement errors, and the like, as well as other factors known to those skilled in the art. Spatial relative terms, such as “below,” “under,” “lower,” “above,” and “upper,” and the like, may be used herein for ease of description to describe the relationship of one element or feature to another, as illustrated in the diagrams. It should be understood that spatial relative terms are intended to encompass different orientations in addition to those depicted in the diagrams. For example, if the objects in the diagrams are flipped, an element described as “below other elements or features” or “under other elements or features” will be oriented “above other elements or features.” Therefore, the illustrative term “below” may encompass both the orientations of above and below. Objects may be oriented in other ways (e.g., rotated 90 degrees or in other orientations), and the spatial relative descriptors used in this document may be interpreted accordingly.

[0020] The section headings used herein are for organizational purposes only and, unless expressly stated otherwise, should not be construed as limiting the subject matter described. It will be understood that many different forms, specific examples, and combinations are possible without departing from the spirit and teachings of this disclosure, and therefore this disclosure should not be considered limited to the specific examples set forth herein. Rather, such examples and specific examples are provided so that this disclosure will be thorough and complete, and will convey the scope of the invention to those skilled in the art.

[0021] I. Overview

[0022] Figures 1 to 3 A schematic diagram illustrating various spatial configurations of a laser processing system. (Reference) Figure 1 The laser energy beam 10 has been deflected by the locator 12 and propagated toward the scanning lens 14 via the folding mirror 16. Although not explicitly stated, relay optics are typically included to relay the pivot point of the locator 12 to the entrance pupil 18 of the scanning lens 14. As shown, the image of the beam from the locator 12 pivots around a virtual pivot point 20 at the entrance pupil 18 of the scanning lens 14, thereby causing acceptable telecentrism of the light rays exiting the scanning lens 14.

[0023] refer to Figure 2 , Figure 1The scanning lens 14 and folding mirror 16 shown have been moved away from the positioner 12, thereby increasing the optical path length between the positioner 12 and the scanning lens 14. This increased optical path length causes the virtual pivot point 20 to move away from the entrance pupil 18 and the scanning lens 14 (e.g., in this case, at or near the surface of the folding mirror 16). This movement of the virtual pivot point 20 away from the scanning lens 14 causes undesirable telecentrism of the light rays leaving the scanning lens 14, which, among other problems, can cause positional errors in the spot position at the workpiece.

[0024] refer to Figure 3 , Figure 1 The scanning lens 14 and folding mirror 16 shown have been moved toward the positioner 12, thereby reducing the optical path length between the positioner 12 and the scanning lens 14. This shortening of the optical path length causes the virtual pivot point 20 to move away from the entrance pupil 18 and toward the scanning lens 14 (and in this case, even beyond the scanning lens 14). This movement of the virtual pivot point 20 toward the scanning lens 14 causes undesirable telecentrism, which can cause positional errors in the spot position at the workpiece, as discussed above. This movement of the virtual pivot point 20 can also cause undesired beam shearing in the entrance pupil 18, thereby reducing the useful deflection range of the positioner 12.

[0025] Figure 4 This illustration depicts a laser processing apparatus according to a specific embodiment of the present invention.

[0026] refer to Figure 4 The specific example shown herein, a laser processing apparatus 100 for processing workpiece 102 (also simply referred to herein as the "apparatus") can be characterized as including a laser source 104 for generating a laser energy beam, one or more positioners (e.g., a first positioner 106, a second positioner 108, a third positioner 110, or any combination thereof), and a scanning lens 112. The scanning lens 112 and the second positioner 108 may be integrated into a scanning head 120, which is described in further detail below.

[0027] Laser energy transmitted along beam path 114 through scanning lens 112 propagates along beam axis 118 for delivery to workpiece 102. The laser energy propagating along beam axis 118 can be characterized as having a Gaussian spatial intensity profile or a non-Gaussian (i.e., "shaped") spatial intensity profile (e.g., a "top-hat" spatial intensity profile). Regardless of the type of spatial intensity profile, the spatial intensity profile can also be characterized as the shape (i.e., cross-sectional shape, also referred to herein as the "spot shape") of the laser energy beam propagating along beam axis 118 (or beam path 114), which can be circular, elliptical, square, rectangular, triangular, hexagonal, annular, or any other shape. As used herein, the term "spot size" refers to the diameter or maximum spatial width (also referred to as "process spot," "spot location," or more simply "spot") of the laser energy beam delivered at the location where the beam axis 118 intersects with the area of ​​the workpiece 102 to be at least partially processed by the delivered laser energy beam. For illustrative purposes herein, spot size is measured as the optical intensity decreasing from the beam axis 118 to at least 1 / e of the optical intensity at the beam axis 118. 2 The radial or lateral distance at the location. Specifically, the spot size of the laser energy beam reaches its minimum at the beam waist. Once delivered to the workpiece 102, the laser energy within the beam can be characterized as irradiating the workpiece 102 with a spot size ranging from 2 μm to 200 μm. However, it should be understood that the spot size can be less than 2 μm or greater than 200 μm. Therefore, the laser energy beam delivered to the workpiece 102 can have a spot size greater than, less than or equal to, 2 μm, 3 μm, 5 μm, 7 μm, 10 μm, 15 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 80 μm, 100 μm, 150 μm, 200 μm, etc., or between any of these values.

[0028] Specifically, the aforementioned positioners (e.g., first positioner 106, second positioner 108, and third positioner 110) are configured to change the relative position between the light spot and the workpiece 102. In view of the following description, it should be understood that the inclusion of the second positioner 108 is optional, subject to the condition that device 100 includes the first positioner 106 and, if applicable, the third positioner 110. Similarly, it should be understood that the inclusion of the third positioner 110 is optional, subject to the condition that device 100 includes the first positioner 106 and, if applicable, the second positioner 108.

[0029] Device 100 may also include one or more other optical components (e.g., beam catchers, beam expanders, beam shapers, beam splitters, apertures, filters, collimators, lenses, mirrors, prisms, polarizers, phase retarders, diffractive optical elements (commonly referred to as DOEs in this art), refractive optical elements (commonly referred to as ROEs in this art), or the like or any combination thereof) to focus, expand, collimate, shape, polarize, filter, separate, combine, crop, absorb, or otherwise modify, adjust, or guide the laser energy beam as it propagates along beam path 114. Optical components such as beam expanders, lenses, beam splitters, prisms, dichroic filters, windows, waveplates, DOEs, and ROEs are generally referred to herein as "transmissive optical components" to the extent that they are formed of a bulk transparent material (which may be coated with one or more anti-reflective coatings or the like) intended to transmit the emitted laser energy beam. As used herein, the assembly of positioners and other optical components, when assembled together in the laser processing equipment 100, can be considered as constituting a "beam path assembly".

[0030] A. Laser source

[0031] In one specific example, laser source 104 is operable to generate laser pulses. Thus, laser source 104 may include a pulsed laser source, a CW laser source, a QCW laser source, a burst-mode laser, or the like or any combination thereof. When laser source 104 includes a QCW or CW laser source, laser source 104 may operate in pulsed mode, or may operate in non-pulsed mode but further include a pulse gating unit (e.g., an acoustic-optic modulator (AOM), a beam chopper, etc.) to temporally modulate the laser radiation beam output from the QCW or CW laser source. Although not explicitly stated, device 100 may optionally include one or more harmonic generating crystals (also referred to as "wavelength conversion crystals") configured to convert the wavelength of the light output from laser source 104. However, in another specific example, laser source 104 may be provided as a QCW or CW laser source and may not include a pulse gating unit. Therefore, laser source 104 can be broadly characterized as operable to generate a laser energy beam, which can be embodied as a series of laser pulses or a continuous or quasi-continuous laser beam, which can then propagate along beam path 114. Although many specific examples discussed herein refer to laser pulses, it should be recognized that continuous or quasi-continuous beams may be used alternatively or additionally whenever appropriate or necessary.

[0032] The laser energy output from laser source 104 may have one or more wavelengths in the ultraviolet (UV), visible, or infrared (IR) range of the electromagnetic spectrum. The laser energy in the UV range of the electromagnetic spectrum may have one or more wavelengths in the range of 10 nm (or approximately) to 385 nm (or approximately), such as 100 nm, 121 nm, 124 nm, 157 nm, 200 nm, 334 nm, 337 nm, 351 nm, 380 nm, or any values ​​between these ranges. The laser energy in the visible green range of the electromagnetic spectrum may have one or more wavelengths in the range of 500 nm (or approximately) to 560 nm (or approximately), such as 511 nm, 515 nm, 530 nm, 532 nm, 543 nm, 568 nm, or any values ​​between these ranges. Laser energies in the IR range of the electromagnetic spectrum can have one or more wavelengths in the range of 750 nm (or above and below) to 15 μm (or above and below), such as 600 nm to 1000 nm, 752.5 nm, 780 nm to 1060 nm, 799.3 nm, 980 nm, 1047 nm, 1053 nm, 1060 nm, 1064 nm, 1080 nm, 1090 nm, 1152 nm, 1150 nm to 1350 nm, 1540 nm, 2.6 μm to 4 μm, 4.8 μm to 8.3 μm, 9.4 μm, 10.6 μm, etc., or between any of these values.

[0033] When the laser energy beam is represented as a series of laser pulses, the laser pulses output by the laser source 104 can have a pulse width or pulse duration (i.e., the full-width at half-maximum (FWHM) based on the optical power in the pulse with respect to time) in the range of 10 fs to 900 ms. However, it will be understood that the pulse duration can be less than 10 fs or greater than 900 ms. Therefore, at least one laser pulse output by the laser source 104 may have a value less than, greater than or equal to 10 fs, 15 fs, 30 fs, 50 fs, 100 fs, 150 fs, 200 fs, 300 fs, 500 fs, 600 fs, 750 fs, 800 fs, 850 fs, 900 fs, 950 fs, 1 ps, 2 ps, 3 ps, 4 ps, 5 ps, 7 ps, 10 ps, ​​15 ps, 25 ps, 50 ps, ​​75 ps, 100 ps, ​​200 ps, ​​500 ps, ​​1 ns, 1.5 ns, Pulse durations of 2ns, 5ns, 10ns, 20ns, 50ns, 100ns, 200ns, 400ns, 800ns, 1000ns, 2μs, 5μs, 10μs, 15μs, 20μs, 25μs, 30μs, 40μs, 50μs, 100μs, 300μs, 500μs, 900μs, 1ms, 2ms, 5ms, 10ms, 20ms, 50ms, 100ms, 300ms, 500ms, 900ms, 1s, etc., or between any of these values.

[0034] The laser pulse output from laser source 104 can have an average power ranging from 5mW to 50kW. However, it should be understood that the average power can be less than 5mW or greater than 50kW. Therefore, the laser pulse output from laser source 104 can have an average power less than, greater than or equal to, 5mW, 10mW, 15mW, 20mW, 25mW, 50mW, 75mW, 100mW, 300mW, 500mW, 800mW, 1W, 2W, 3W, 4W, 5W, 6W, 7W, 10W, 15W, 18W, 25W, 30W, 50W, 60W, 100W, 150W, 200W, 250W, 500W, 2kW, 3kW, 20kW, 50kW, etc., or between any of these values.

[0035] The laser pulse can be output by the laser source 104 at a pulse repetition rate in the range of 5 kHz to 5 GHz. However, it will be understood that the pulse repetition rate can be less than 5 kHz or greater than 5 GHz. Therefore, the laser pulse can be output by the laser source 104 at a pulse repetition rate less than, greater than or equal to, 50 kHz, 100 kHz, 175 kHz, 225 kHz, 250 kHz, 275 kHz, 500 kHz, 800 kHz, 900 kHz, 1 MHz, 1.5 MHz, 1.8 MHz, 1.9 MHz, 2 MHz, 2.5 MHz, 3 MHz, 4 MHz, 5 MHz, 10 MHz, 20 MHz, 50 MHz, 60 MHz, 100 MHz, 150 MHz, 200 MHz, 250 MHz, 300 MHz, 350 MHz, 500 MHz, 550 MHz, 600 MHz, 900 MHz, 2 GHz, 10 GHz, etc., or between any of these values.

[0036] In addition to wavelength, average power, and pulse duration and pulse repetition rate when the laser energy beam is a series of laser pulses, the laser energy beam delivered to workpiece 102 may be characterized by one or more other characteristics such as pulse energy and peak power. These characteristics may be selected (e.g., depending on the circumstances, based on one or more other characteristics such as wavelength, pulse duration, average power, and pulse repetition rate) to achieve an optical intensity (in W / cm²) sufficient to process workpiece 102 (e.g., form one or more features). 2 Measurement), flux (in J / cm) 2 Workpiece 102 at the spot of the irradiation process (measurement).

[0037] Examples of laser types for laser source 104 may be characterized as gas lasers (e.g., carbon dioxide lasers, carbon monoxide lasers, excimer lasers, etc.), solid-state lasers (e.g., Nd:YAG lasers, etc.), rod lasers, fiber lasers, photonic crystal rod / fiber lasers, passively mode-locked solid-state bulk or fiber lasers, dye lasers, mode-locked diode lasers, pulsed lasers (e.g., ms, ns, ps, fs pulsed lasers), CW lasers, QCW lasers, or similar types or any combination thereof. Depending on the configuration of these lasers, gas lasers (e.g., carbon dioxide lasers, etc.) may be configured to operate in one or more modes (e.g., in CW mode, QCW mode, pulsed mode, or any combination thereof).Specific examples of laser sources that can be provided as laser source 104 include one or more laser sources, such as: BOREAS, HEGOA, SIROCCO, or CHINOOK series lasers manufactured by EOLITE; PYROFLEX series lasers manufactured by PYROPHOTONICS; PALADIN Advanced355, DIAMOND series (e.g., DIAMOND E, G, J-2, J-3, J-5 series), FLARE NX, MATRIX QS DPSS, MEPHISTO Q, AVIA LX, AVIA NX, RAPID NX, HYPERRAPID NX, RAPID, HELIOS, FIDELITY, MONACO, OPERA, or RAPID FX series lasers manufactured by SPECTRA; Lasers manufactured by PHYSICS, including the Aschend, Excelior, Explorer, Hippo, Navigator, Quantaray, Quasar, Spirit, Talon, or Vgen series; lasers manufactured by SYNRAD, including the Pulstar or Firestrar series; Truflo series lasers (e.g., Truflo 2000, 2600, 3000, 3200, 3600, 4000, 5000, 6000, 6000, 8000, 10000, 12000, 15000, 20000), Trucoax series lasers (e.g., Trucoax 1000), or Trudisk, Truplese, Trudoid, Trufiber, or Trumicro series lasers, all manufactured by TRUMPF; FCPA μJEWEL or FEMTOLITE series lasers manufactured by IMRA AMERICA; and lasers manufactured by AMPLITUDE. TANGERINE and SATSUMA series lasers (and MIKAN and T-PULSE series oscillators) manufactured by SYSTEMES; CL, CLPF, CLPN, CLPNT, CLT, ELM, ELPF, ELPN, ELPP, ELR, ELS, FLPN, FLPNT, FLT, GLPF, GLPN, GLR, HLPN, HLPP, RFL, TLM, TLPN, TLR, ULPN, ULR, VLM, VLPN, YLM, YLPF, YLPN, YLPP, YLR, YLS, FLPM, FLPMT, DLM, BLM or DLR series lasers (e.g., including GPLN-100-M, GPLN-500-QCW, GPLN-500-M, GPLN-500-R, GPLN-2000-S, etc.) or similar or any combination thereof manufactured by IPG PHOTONICS.

[0038] B. First Positioner

[0039] The first positioner 106 is configured, positioned, or otherwise placed in the beam path 114 and operable to diffract, reflect, refract, or similar or any combination thereof (i.e., to “deflect”) the laser pulses generated by the laser source 104, so as to deflect or impart movement to the beam path 114 (e.g., relative to the scanning lens 112) and thus deflect or impart movement to the beam axis 118 relative to the workpiece 102. Specifically, the first positioner 106 is operable to impart movement to the beam axis 118 relative to the workpiece 102 along the X-axis (or direction), Y-axis (or direction), or a combination thereof. Although not stated, the X-axis (or X direction) should be understood to refer to an axis (or direction) orthogonal to the stated Y and Z axes (or directions).

[0040] Specifically, the first positioner 106 can be provided as a galvanometer mirror system, an AO deflector (AOD) system, an electro-optic (EO) deflector (EOD) system, a fast-steering mirror (FSM) system, or similar or any combination thereof. The AOD of an AOD system typically includes AO units formed from materials such as crystalline germanium (Ge), gallium arsenide (GaAs), lumbromine (PbMoO4), tellurium dioxide (TeO2), crystalline quartz, glassy SiO2, arsenic trisulfide (As2S3), lithium niobate (LiNbO3), or similar or any combination thereof. The EOD of an EOD system typically includes EO units formed from lithium niobate, potassium tantalate niobate, etc. Within the limits of configuring the AO and EO units to transmit an input laser energy beam, the AO and EO units can be considered as types of transmission optical components.

[0041] C. Second Positioner

[0042] The second positioner 108 is disposed in the beam path 114 and operable to diffract, reflect, refract, or similar or any combination thereof (i.e., to "deflect" the laser pulse) generated by the laser source 104 and transmitted by the first positioner 106, so as to deflect or impart movement to the beam path 114 (e.g., relative to the scanning lens 112) and thus deflect or impart movement to the beam axis 118 relative to the workpiece 102. Specifically, the second positioner 108 is operable to impart movement to the beam axis 118 relative to the workpiece 102 along the X-axis (or direction), Y-axis (or direction), or a combination thereof.

[0043] In view of the above, it should be understood that the second positioner 108 may be provided as a micro-electro-mechanical-system (MEMS) mirror or mirror array, an AOD system, an electro-optic deflector (EOD) system, a fast control mirror (FSM) element (e.g., with piezoelectric actuators, electrostrictive actuators, voice coil actuators, etc.), a galvanometer mirror system, a resonant scanning mirror system, a rotating polygon scanner, or the like or any combination thereof.

[0044] In one specific example, the second positioner 108 may be provided as a biaxial galvanometer mirror system including two galvanometer mirror assemblies, namely, a first galvanometer mirror assembly (e.g., an X-axis galvanometer mirror assembly) configured to impart movement of the beam axis 118 relative to the workpiece 102 along the X-axis, and a second galvanometer mirror assembly (e.g., a Y-axis galvanometer mirror assembly) configured to impart movement of the beam axis 118 relative to the workpiece 102 along the Y-axis. However, in another specific example, the second positioner 108 may be provided as a galvanometer mirror system including only a single galvanometer mirror assembly configured to impart movement of the beam axis 118 relative to the workpiece 102 along both the X and Y axes. In yet another specific example, the second positioner 108 may be provided as a rotating polygonal mirror system, etc. Therefore, it should be understood that, depending on the specific configuration of the second positioner 108 and the first positioner 106, the second positioning bandwidth may be greater than or equal to the first positioning bandwidth.

[0045] D. Third Positioner

[0046] In the specific examples described herein, the third positioner 110 includes one or more linear stages (e.g., each capable of providing translational movement of the workpiece 102 along the X, Y, and / or Z directions), one or more rotary stages (e.g., each capable of providing rotational movement of the workpiece 102 about an axis parallel to the X, Y, and / or Z directions), or similar combinations thereof, which are configured and arranged to provide relative movement between the workpiece 102 and the scanning lens 112, and thus relative movement between the workpiece 102 and the beam axis 118. According to the specific examples described herein, and although not explicitly stated, the third positioner 110 includes one or more stages configured and adapted to provide relative movement between the scanning lens 112 and the first positioner 106.

[0047] Given the configuration described herein, it should be recognized that the movement of the process spot relative to the workpiece 102 (e.g., as imparted by the first positioner 106 and / or the second positioner 108) may overlap with the movement of the workpiece 102 or the scanning lens 112, as imparted by the third positioner 110.

[0048] In the specific example described, the third positioner 110 is operable to move the workpiece 102. However, in another specific example, the third positioner 110 is configured and operable to move the scanning head 120, and, depending on the circumstances, one or more components such as the first positioner 106 and the workpiece 102 may remain stationary. In yet another specific example, the third positioner 110 may be provided as a so-called "separation axis" positioning system, wherein the scanning lens 112 and, depending on the circumstances, one or more other components (such as the first positioner 106 and the second positioner 108) are carried by one or more linear or rotary stages (e.g., mounted on a frame, bracket, etc.), and the workpiece 102 is carried by one or more other linear or rotary stages. When provided as a "separation axis" positioning system, the third positioner 110 includes one or more linear or rotary stages configured and operable to move one or more components such as the scanning head 120 and one or more linear or rotary stages configured and operable to move the workpiece 102. For example, the third positioner 110 may include a Y-stage for imparting movement of the workpiece 102 along the Y direction and an X-stage for imparting movement of the scanning head 120 along the X direction. Some examples of a split-axis positioning system that may be advantageously or beneficially used in the device 100 include any of the systems disclosed below: U.S. Patent Nos. 5,751,585, 5,798,927, 5,847,960, 6,606,999, 7,605,343, 8,680,430, 8,847,113, or U.S. Patent Application Publication No. 2014 / 0083983, or any combination thereof, each of which is incorporated herein by reference in its entirety.

[0049] In one specific embodiment of the third positioner 110 including a Z-stage, the Z-stage can be configured and configurable to move the workpiece 102 along the Z direction; in this case, the Z-stage can be carried by one or more of the other aforementioned stages used for moving or positioning the workpiece 102, or any combination thereof. In another specific embodiment of the third positioner 110 including a Z-stage, the Z-stage can be configured and configurable to move the scanning head along the Z direction; therefore, when the third positioner 110 is provided as a separate stage positioning system, the Z-stage can carry or be carried by the X-stage. Moving the workpiece 102 or the scanning head along the Z direction can cause a change in the spot size at the workpiece 102.

[0050] In another specific example, one or more components, such as the first positioner 106, the second positioner 108, and the scanning lens 112, may be carried by an articulated multi-axis robotic arm (e.g., a 2-axis, 3-axis, 4-axis, 5-axis, or 6-axis arm). In this specific example, the second positioner 108 and / or the scanning lens 112 may be carried by the end effector of the robotic arm, if appropriate. In yet another specific example, the workpiece 102 may be carried directly on the end effector of the articulated multi-axis robotic arm (i.e., without the third positioner 110). In still another specific example, the third positioner 110 may be carried on the end effector of the articulated multi-axis robotic arm.

[0051] E. Scanning lens

[0052] The scanning lens 112 (e.g., provided as a single lens or a compound lens) is typically configured to focus a laser energy beam guided along the beam path, typically to produce a beam waist that can be positioned at or near the desired process spot. The scanning lens 112 may be provided as a non-telecentric f-θ lens (as shown), a telecentric f-θ lens, an axial-cone lens (in which case a series of beam waists are produced, resulting in several process spots displaced relative to each other along the beam axis 118), or similar or any combination thereof.

[0053] In one specific example, the scanning lens 112 is provided as a fixed-focus lens and coupled to a scanning lens positioner (e.g., a lens actuator, not shown) operable to move the scanning lens 112 (e.g., to change the position of the beam waist along the beam axis 118). For example, the lens actuator can be provided as a voice coil operable to linearly translate the scanning lens 112 along the Z direction. In this case, the lens actuator can be considered as a component of the aforementioned third positioner 110. Additionally, the fixed-focus lens can be formed from materials such as fused silica, optical glass, zinc selenide, zinc sulfide, germanium, gallium arsenide, magnesium fluoride, etc. In another specific example, the scanning lens 112 is provided as a variable-focus lens (e.g., a zoom lens or a so-called "liquid lens," with technology currently available from COGNEX, VARIOPTIC, etc.), which can be actuated (e.g., via a lens actuator) to change the position of the beam axis 118 along the beam waist. Changing the position of the beam waist along the beam axis 118 can cause a change in the size of the spot at the workpiece 102.

[0054] As described above, in one specific example, the scanning lens 112 and the second positioner 108 are integrated into a common scanning head 120. Therefore, in a specific example where the device 100 includes a lens actuator, the lens actuator may be coupled to the scanning lens 112 (e.g., to enable movement of the scanning lens 112 relative to the second positioner 108 within the scanning head 120). Alternatively, the lens actuator may be coupled to the scanning head 120 and operable to enable movement of the scanning head itself, in which case the scanning lens 112 and the second positioner 108 will move together. In either case, the lens actuator can be considered here as a component of the aforementioned third positioner 110. In another specific example, the scanning lens 112 and the second positioner 108 are integrated into separate housings (e.g., such that the housing incorporating the scanning lens 112 is movable relative to the housing incorporating the second positioner 108).

[0055] F. Controller

[0056] Generally, device 100 includes one or more controllers, such as controller 122, to control or facilitate the operation of device 100. In a specific example, controller 122 (e.g., via one or more wired or wireless, serial or parallel communication links, such as USB, RS-232, Ethernet, Firewire, Wi-Fi, RFID, NFC, Bluetooth, Li-Fi, SERCOS, MARCO, EtherCAT, or similar or any combination thereof) is communicatively coupled to one or more components of device 100, such as laser source 104, first positioner 106, second positioner 108, third positioner 110, lens actuator, scanning lens 112 (when provided as a variable focal length lens), clamp, etc., which can thus operate in response to one or more control signals output by controller 122.

[0057] For example, controller 122 may control the operation of the first positioner 106, the second positioner 108, or the third positioner 110, or any combination thereof, to impart relative movement between the beam axis and the workpiece, thereby causing relative movement between the process spot and the workpiece 102 along a path or trajectory (also referred to herein as the "process trajectory") within the workpiece 102. It will be understood that any two or all three of these positioners may be controlled such that two positioners (e.g., first positioner 106 and second positioner 108, first positioner 106 and third positioner 110, or second positioner 108 and third positioner 110) or all three positioners simultaneously impart relative movement between the process spot and the workpiece 102 (thus imparting a "compound relative movement" between the beam axis and the workpiece). Of course, at any given time, it is possible to control only one positioner (e.g., the first positioner 106, the second positioner 108, or the third positioner 110) to give relative movement between the process spot and the workpiece 102 (thereby giving "non-compound relative movement" between the beam axis and the workpiece).

[0058] Other examples of operations that can control one or more of the aforementioned components include any operation, function, process, and method, as disclosed in U.S. Patent Nos. 5,751,585, 5,847,960, 6,606,999, 8,680,430, and 8,847,113, or as disclosed in U.S. Patent Nos. 4,912,487, 5,633,747, 5,638,267, and 5,917,300. Nos. 6,314,463, 6,430,465, 6,600,600, 6,606,998, 6,816,294, 6,947,454, 7,019,891, 7,027,199, 7,133,182, 7,133,186, 7,133,187, 7,133,188, 7,244,906, and 7,245,412 Disclosed in No. 7,259,354, No. 7,611,745, No. 7,834,293, No. 8,026,158, No. 8,076,605, No. 8,288,679, No. 8,404,998, No. 8,497,450, No. 8,648,277, No. 8,896,909, No. 8,928,853, and No. 9,259,802, or in U.S. Patent Application Publication No. 2014 The following patents are disclosed in: No. 0026351, No. 2014 / 0196140, No. 2014 / 0263201, No. 2014 / 0263212, No. 2014 / 0263223, No. 2014 / 0312013, or German Patent No. DE102013201968B4, or International Patent Publication No. WO2009 / 087392, each of which is incorporated herein by reference in its entirety. In another example, controller 122 may control the operation of any positioner including one or more AODs (e.g., in some specific instances, a first positioner 106, a second positioner 108, or a combination thereof) to change the spot shape or spot size of the laser energy beam delivered to the process spot (e.g., by chirping an RF signal applied to one or more ultrasonic transducer elements of one or more AODs, by applying a spectrally shaped RF signal to one or more ultrasonic transducer elements of one or more AODs, or similar or any combination thereof), as disclosed, for example, in International Patent Publication No. WO2017 / 044646A1, which is incorporated herein by reference in its entirety. The applied RF signal may be chirped linearly or nonlinearly in any desired or suitable manner. For example, the applied RF signal may be chirped at a first rate and then at a second rate to diffract the laser energy beam, thereby delivering the AO unit in two different ways.In this case, the first speed may be slower or faster than the second speed.

[0059] Generally, controller 122 includes one or more processors operable to generate the aforementioned control signals upon execution of instructions. The processors may be programmable processors (e.g., including one or more general-purpose computer processors, microprocessors, digital signal processors, or the like or any combination thereof) provided as operable to execute instructions. Instructions executable by the processor may be implemented as software, firmware, etc., or as any suitable form of circuit system, including programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), field-programmable object arrays (FPOAs), application-specific integrated circuits (ASICs) (including digital, analog, and mixed-signal analog / digital circuit systems), or the like or any combination thereof. Execution of instructions may be performed on a single processor, distributed across processors, across processors within a device, or across a network of devices, or the like or any combination thereof.

[0060] In one specific example, controller 122 includes tangible media such as computer memory, which can be accessed by a processor (e.g., via one or more wired or wireless communication links). As used herein, "computer memory" includes magnetic media (e.g., magnetic tape, hard disk drives, etc.), optical discs, volatile or non-volatile semiconductor memories (e.g., RAM, ROM, inverse NAND flash memory, inverse OR flash memory, SONOS memory, etc.), and can be accessed locally, remotely (e.g., across a network), or in combination thereof. Specifically, instructions may be stored as computer software (e.g., executable code, files, instructions, etc., library files, etc.) that can be readily licensed by a person skilled in the art based on the description provided herein, written, for example, in C, C++, Visual Basic, Java, Python, Tel, Perl, Scheme, Ruby, assembly languages, hardware description languages ​​(e.g., VHDL, Verilog, etc.). Computer software is typically stored in one or more data structures transferred by computer memory.

[0061] Although not shown in the figures, one or more drivers (e.g., RF drivers, servo drivers, line drivers, power supplies, etc.) may be communicatively coupled to the inputs of one or more components, such as laser source 104, first positioner 106, second positioner 108, third positioner 110, lens actuator, scanning lens 112 (when provided as a variable focal length lens), clamp, etc. Therefore, one or more components such as laser source 104, first positioner 106, second positioner 108, third positioner 110, lens actuator, scanning lens 112 (when provided as a variable focal length lens), clamp, etc., can be considered as including any suitable driver, as known in the art. Each of these drivers typically includes an input communicatively coupled to controller 122, and controller 122 is operable to generate one or more control signals (e.g., trigger signals, etc.) that can be transmitted to the inputs of one or more drivers associated with one or more components of device 100. Components such as laser source 104, first positioner 106, second positioner 108, third positioner 110, lens actuator, scanning lens 112 (when provided as a variable focal length lens), clamp, etc., therefore respond to the control signal generated by controller 122.

[0062] Although not shown in the figures, one or more additional controllers (e.g., component-specific controllers) may be communicatively coupled to the input of the driver, which is communicatively coupled to (and thus associated with) components such as laser source 104, first positioner 106, second positioner 108, third positioner 110, lens actuator, scanning lens 112 (when provided as a variable focal length lens), clamp, etc. In this specific example, each component-specific controller may be communicatively coupled to controller 122 and operable to generate one or more control signals (e.g., trigger signals, etc.) in response to one or more control signals received from controller 122, which may then be transmitted to the input of the driver to which the controller is communicatively coupled. In this specific example, the component-specific controller may operate in a manner similar to that described with respect to controller 122.

[0063] In another specific instance of providing one or more component-specific controllers, a component-specific controller associated with a component (e.g., laser source 104) may be communicatively coupled to a component-specific controller associated with another component (e.g., first positioner 106, etc.). In this specific instance, one or more of the component-specific controllers may be operable to generate one or more control signals (e.g., trigger signals, etc.) in response to one or more control signals received from one or more other component-specific controllers.

[0064] II. Specific examples of resolving the misalignment of the pivot point relative to the SLEP

[0065] As described above, one or more components of the third positioner 110 enable movement of the scanning lens 112 relative to the first positioner 106. Therefore, the optical path length between the scanning lens 112 and the first positioner 106 is variable. The following is a discussion of illustrative specific examples that can be used to compensate for movement of the scanning lens 112 relative to the first positioner 106 to ensure that the laser energy beam propagating along the beam path 114 rotates around a pivot point located at or at least very close to the entrance pupil of the scanning lens 112.

[0066] A. Specific Example 1: First Positioner Driven by Actuator

[0067] Figure 5 and Figure 6 A specific example of an actuator-driven first positioner 106 is shown. For example... Figure 5 As shown, the first positioner 106 is coupled to the actuator 150 (e.g., a linear motion stage), and the fixed relay optics 126 is positioned within the beam path 114 at a location between the first positioner 106 and the scanning lens 112. In a specific instance where the scanning lens 112 is coupled to one or more actuators of the third positioner 110 (e.g., one or more linear actuators coupled to move the scanning lens 112 along any of the X, Y, and / or Z directions), the actuator 150 is not part of the third positioner 110. However, the actuator 150 is configured and operable to move the first positioner 106 in a direction corresponding to the direction of movement of the scanning lens 112 as given by the third positioner 110. As will be understood, the actuator 150 is operable (e.g., in response to one or more commands output by the controller 122) to move the first positioner 106 so that the scanning lens 112 moves (e.g., as...). Figure 6 (As shown in the diagram) a constant (or at least substantially constant) optical path length is maintained between the first positioner 106 and the entrance pupil 132 of the scanning lens 112. Maintaining the optical path length ensures that the laser energy beam 116 has acceptable telecentrism when guided toward the workpiece 102. Although Figure 6 The scanning lens 112 is shown moving toward the fixed relay optics 126, but it should be understood that the scanning lens 112 can move away from the fixed relay optics 126, so the actuator 150 can move the first positioner 106 toward the fixed relay optics 126 in order to maintain a constant optical path length between the first positioner 106 and the entrance pupil 132.

[0068] During operation, actuator 150 can cause the first positioner 106 to move by an amount equal to or different from the distance traversed by the scanning lens 112. For example, in one specific instance, the fixed relay optics 126 has a magnification M equal to (or at least substantially equal to) 1, such that the first positioner 106 must move along the beam path away from the fixed relay optics 126 to reposition the pivot point 134 at the center of the entrance pupil 132 by a distance equal to (or at least substantially equal to) the distance the pivot point 134 moves along the beam path. In another specific instance, the fixed relay optics 126 has a magnification M greater than 1, such that the first positioner 106 must move along the beam path away from the fixed relay optics 126 to reposition the pivot point 134 at the center of the entrance pupil 132 by a distance less than the distance the pivot point 134 moves along the beam path. For example, in one specific instance, the fixed relay optics 126 may have a magnification M equal to (or at least substantially equal to) 2. Therefore, if the scanning lens 112 moves 100 mm along the beam path 114 toward the fixed relay optics 126, the actuator 150 only needs to move the first positioner 10625 mm along the beam path 114 (i.e., 100 mm / M). 2 =25mm). It should be understood that the magnification of the fixed relay optics 126 can be adjusted in any other desired or beneficial manner.

[0069] Figure 5 and Figure 6 This describes a configuration in which the actuator 150 moves the first positioner 106 in a direction different from the direction in which the scanning lens 112 can move. However, it should be understood that the actuator 150 can move the first positioner 106 in one direction or any other direction, subject to, for example, one or more mirrors being arranged within the beam path to adequately relay the beam path 114 from the first positioner 106 to the scanning lens 112.

[0070] B. Specific Example 2: Portable Optical Relay System

[0071] As discussed above, the optical relay system is operable to position the image of the first positioner 106 at the entrance pupil 132 of the scanning lens 112, thereby causing the laser energy beam 116 propagating along the beam path 114 to rotate around a pivot point 134 located at or at least very close to the entrance pupil 132 of the scanning lens 112. Movement of the scanning lens 112 relative to the first positioner 106 (or the second positioner 108) can cause a misalignment of the image of the first positioner 106 away from the entrance pupil 132. In one specific example, the optical relay system 200 can move synchronously with the movement of the scanning lens 112 to maintain the position of the pivot point 134 at the entrance pupil 132, thereby ensuring acceptable telecentrism of the laser energy beam 116 when guided toward the workpiece 102.

[0072] Figure 7A and 7B Two spatial states illustrate a specific example of a movable optical relay system, comprising: an optical relay 200 configured to optically communicate with a first positioner 106 and mounted on a component of a third positioner 110 (e.g., a linear stage 218 operable to move the optical relay 200 along the X-axis, as illustrated); and several mirrors (e.g., mirrors 214a, 214b, and 216). The optical relay 200 is mounted to a bracket 210, which is then movable by the linear stage 218 (e.g., in response to one or more commands output by a controller 122). Similarly, mirror 216, the second positioner 108, and the scanning lens 112 are mounted together with the optical relay 200 on the bracket 210 of the linear stage 218. The linear stage 218 can be mounted to a structure 217, such as the frame or support of a laser processing apparatus 100. In another specific example, the optical relay 200 may be mounted to an auxiliary stage (not shown) instead of stage 218. During use, the auxiliary stage can position the optical relay 200 in response to the movement imparted to the second positioner 108 and scanning lens 112 by the linear stage 218. Mirrors 214a and 214b (e.g., folding mirrors) are mounted to structure 217. Thus, the linear stage 218 can move the second positioner 108 and scanning lens 112, as well as the optical relay 200 and mirror 216, relative to the first positioner 106 and mirrors 214a and 214b. As illustrated, mirrors 214a, 214b, and 216 are configured to position the optical relay 200 in optical communication with the scanning lens 112.

[0073] The optical relay 200 further includes an optical input 206, an optical output 208, a first reflector 212a having a first reflective surface 204a, and a second reflector 212b having a second reflective surface 204b. The optical relay 200 further includes a first lens 202a mounted in the optical input 206 and a second lens 202b mounted in the optical output 208.

[0074] In the specific example described, the first reflective surface 204a and the second reflective surface 204b are parallel to each other (or at least substantially parallel to each other). It should be understood that the first reflective surface 204a and the second reflective surface 204b may not be parallel to each other. Based on the configuration described above, the laser energy beam 116 enters the optical input 206 via the first lens 202a and is incident on the first reflective surface 204a, which reflects back to the second reflective surface 204b. The laser energy beam 116 reflects back and forth multiple times between the reflective surfaces 204a and 204b until it exits the optical relay 200 via the optical output 208. The folding of the optical path between the reflective surfaces 204a and 204b allows the optical relay 200 to be compactly mounted to the bracket 210. After exiting the optical output 208 via the second lens 202b, the laser energy beam 116 propagates to the mirror 214a. A laser energy beam 116 is reflected from mirror 214a to mirror 214b, where it is then reflected back to mirror 216 configured to reflect the laser energy beam 116 to scanning lens 112 (e.g., via second positioner 108). In the specific example described, second positioner 108 is provided as a biaxial galvanometer mirror system, and the entrance pupil 132 of scanning lens 112 is located between its X and Y axis galvanometer mirror assemblies. Under certain operating conditions of device 100, the power of the laser energy beam 116 is high enough to cause damage to reflective surfaces 204a and 204b if it is focused directly onto them. To avoid this situation, in the specific example described, the first lens 202a is configured to focus the laser energy beam 116 at a point between the first reflective surface 204a and the second reflective surface 204b (e.g., nominally halfway between reflective surfaces 204a and 204b), thereby reducing the laser flux at surfaces 204a and 204b sufficiently to avoid damage to them.

[0075] Specifically, the optical relay 200 can be configured to impart amplification to the laser energy beam 116 in order to compensate for changes in the optical path length caused by the optical path being folded into two or more branches (e.g., depending on the configuration of the device 100) so as to keep the pivot point 134 at or near the entrance pupil 132 of the scanning lens.

[0076] In a specific instance, refer to Figure 7A The optical input 206 is located at a distance X0 from the first locator 106. For example... Figure 7BAs shown, the optical input 206 is repositioned to a distance X1 from the first positioner 106, having moved a distance D = X1 - X0 (e.g., after operation of the linear stage 218). When the optical relay 200 moves in the +X direction, the distance between the optical output 208 and the scanning lens 112 changes by a factor of 2 because the laser energy beam 116 is folded into two branches by mirrors 214a and 214b. Consequently, the effect is that the image of the first positioner 106 has moved a distance 2*D away from the scanning lens 112, potentially causing the relay pivot point 134 to shift out of the entrance pupil 132, which will cause a telecentric error in the beam guided to the workpiece 102. To account for this situation, in this specific example, lenses 202a and 202b can impart a lateral magnification of M = sqrt(2) = 1.414 to the laser energy beam 116, such that the width of the beam exiting the optical output 208 is 1.414 times the width of the beam entering the optical input 206. The resulting longitudinal magnification is M 2 =2, so that the relay pivot point 134 moves a distance of 2*D, thereby maintaining the position of the relay pivot point 134 and the beam size of the laser energy beam 116 at the entrance pupil 132 when the scanning lens 112 and the optical relay 200 move by means of the linear stage 218.

[0077] In another specific example, the optical path can be folded into three branches, such that when the optical input 206 is repositioned to a distance X1 from the first positioner 106, it has moved a distance D = X1 - X0 (e.g., after operation of the linear stage 218). When the optical relay 200 moves in the +X direction, the distance between the optical output 208 and the scanning lens 112 will change by a factor of 3 because the laser energy beam 116 is folded into three branches. Thus, the effect is that the image of the first positioner 106 has moved a distance of 3*D away from the scanning lens 112. To account for this situation, in this specific example, lenses 202a and 202b can impart a lateral magnification of M = sqrt(3) = 1.732 to the laser energy beam 116, such that the width of the beam leaving the optical output 208 is 1.732 times the width of the beam entering the optical input 206. The resulting longitudinal magnification is M 2 =3, causing the relay pivot point 134 to move a distance of 3*D, thereby maintaining the position of the relay pivot point 134 and the beam size of the laser energy beam 116 at the entrance pupil 132 as the scanning lens 112 and optical relay 200 move by means of the linear stage 218. It should be understood that in other possible configurations of the device 100, the optical path between the relays 200 can be folded into more than three branches, and lenses 202a and 202b can be configured to impart appropriate magnification to the laser energy beam 116 to compensate for this and maintain the pivot point 134 at or near the entrance pupil 132.

[0078] Although the second locator 108 is in Figure 7A and Figure 7B The description indicates that it overlaps with the entrance pupil 132, but it should be understood that the second locator 108 can alternatively be positioned to avoid overlap with the entrance pupil 132. For example, Figure 7A and 7B The mirror 216 shown can be replaced by the second locator 108.

[0079] C. Specific Example 3: Optical retardation line with a regressor

[0080] Figure 8 and Figure 9 The positional state of an optical relay system provided with an optical delay line (such as optical delay line 300) and a regressor is illustrated. Optical delay line 300 receives a laser energy beam 116 from first positioner 106 and relays it to scanning lens 112 via folding mirror 130. It should be understood that folding mirror 130 is optional and may be omitted if the orientation of one or more other components of laser processing equipment 100 (e.g., first positioner 106, second positioner 108, scanning lens 112, optical delay line 300, or the like or any combination thereof) is modified to ensure that laser energy beam 116 propagates from first positioner 106 to scanning lens 112. Laser energy beam 116 is thus guided to a relay pivot point 134 at or near the entrance pupil 132 of scanning lens 112.

[0081] Specifically, the optical delay line 300 includes a motion system 308 (e.g., a linear stage), a regressor reflector 310, a relay reflector 320, and a delay line body 302. The motion system 308, the regressor reflector 310, and the relay reflector 320 are mounted on the delay line body 302, and the regressor reflector 310 is movable relative to the relay reflector 320 by means of the motion system 308. In one specific embodiment, the optical delay line 300 is mounted within a laser processing apparatus 100 to be fixed in position relative to a first positioner 106, and the scanning lens 112 is movable relative to the optical delay line 300. In another specific embodiment, the optical delay line 300 is movable relative to the first positioner 106 and can be fixed in position relative to the scanning lens 112. For example, the optical delay line 300 may be coupled to one or more actuators of the third positioner 110 (e.g., coupled to one or more linear actuators operable to move the scanning lens 112 along any of the X, Y, and / or Z directions). In another specific embodiment, the optical delay line 300 may be movable relative to the first positioner 106 and the scanning lens 112.

[0082] In the specific example described, the recurrent reflector 310 is an angular reflector (also called a right-angle prism) comprising a first reflecting surface 314, a second reflecting surface 316, and a third reflecting surface 318, which are generally orthogonal to each other. In another specific example, the recurrent reflector 310 does not need to have a third reflecting surface 318. In other specific examples, the recurrent reflector 310 may also be provided as a pair of mirrors or spherical recurrent reflectors. Those skilled in the art will understand that any of these types of recurrent reflectors can be used in the optical delay line 300. In the specific example described, when the recurrent reflector 310 has three reflecting surfaces 314, 316, and 318, the light beam propagating to and from the recurrent reflector 310 remains parallel, regardless of the orientation of the light beam to the reflecting surfaces of the recurrent reflector 310.

[0083] The repeater reflector 320 is configured to reflect the laser energy beam 116 to the return reflector 310 and reflect the laser energy beam returning from the return reflector 310 to the scanning lens 112. In a specific example, the repeater reflector 320 includes a first reflective surface 324 and a second reflective surface 326 attached to or formed on the repeater reflector body 322. In a specific example, the first reflective surface 324 and the second reflective surface 326 are orthogonally oriented to each other. In another specific example, the first reflective surface 324 and the second reflective surface 326 may not be orthogonally oriented to each other. In another specific example, the repeater reflector 320 may provide two mirrors mounted to the repeater reflector body 322. It should be understood that any variety of optical devices or optical surfaces may be mounted to or formed on the repeater reflector body 322.

[0084] In a specific example where the scanning lens 112 is movable relative to the optical delay line 300 (e.g., the optical delay line 300 is mounted within the laser processing apparatus 100 to be fixed in position relative to the first positioner 106), when the scanning lens 112 moves relative to the first positioner 106 (e.g., in the +X direction), the regressor reflector 310 moves relative to the relay reflector 320 (e.g., in the -Z direction). Therefore, the optical path length between the scanning lens 112 and the first positioner 106 is maintained such that when the scanning lens 112 moves, the pivot point 134 of the laser energy beam 116 remains at or near the entrance pupil 132 of the scanning lens 112. For example, refer to... Figure 8 and Figure 9 During use, the scanning lens 112 moves in the +X direction from a distance X0 relative to the optical delay line 300 (as shown in Figure 8) to a distance X1 relative to the delay line 300 (as shown in Figure 8). Figure 9As shown in the diagram), it changes to ΔX = X1 - X0. Synchronized with the movement of the scanning lens 112, the returning reflector 310 moves in the -Z direction from a distance Z0 relative to the relay reflector 320 (as shown in the diagram). Figure 8 (As shown in the image) Move to a distance Z1 relative to the relay reflector 320 (e.g.) Figure 9 As shown in the diagram, the change in position is ΔZ = Z0 - Z1. In this specific example, ΔX ≈ 2ΔZ. Since the optical path is folded into two branches in the Z direction by the optical delay line 300, the original optical path length from the first positioner 106 to the scanning lens 112 is maintained when ΔX ≈ 2ΔZ.

[0085] In a specific instance where the optical delay line 300 is movable relative to the first positioner 106 (e.g., via the scanning lens 112) or is itself movable relative to the scanning lens 112, when the optical delay line 300 moves relative to the first positioner 106 (or relative to the scanning lens 112) (e.g., in the +X direction), the regressor reflector 310 is movable relative to the relay reflector 320 (e.g., in the -Z direction). Therefore, the optical path length between the scanning lens 112 and the first positioner 106 is maintained such that when the scanning lens 112 moves, the pivot point 134 of the laser energy beam 116 remains at or near the entrance pupil 132 of the scanning lens 112. For example, refer to... Figure 8 and Figure 9 During use, the optical delay line 300 moves in the +X direction from a distance X2 relative to the first locator 106 to a distance X3 relative to the first locator 106, changing to ΔX = X3 - X2. Synchronously with the movement of the optical delay line 300 in the +X direction, the resetting reflector 310 moves in the -Z direction from a distance Z0 relative to the relay reflector 320 (e.g., ...). Figure 8 (As shown in the image) Move to a distance Z1 relative to the relay reflector 320 (e.g.) Figure 9 As shown in the diagram, the change in position is ΔZ = Z0 - Z1. In this specific example, ΔX ≈ 2ΔZ. Since the optical path is folded into two branches in the Z direction by the optical delay line 300, the original optical path length from the first positioner 106 to the scanning lens 112 is maintained when ΔX ≈ 2ΔZ.

[0086] It should be understood that the optical delay line 300 can be configured to fold the optical path between the first positioner 106 and the scanning lens 112 into any number of branches, and thus provide any ratio between ΔX and ΔZ. For example, the optical delay line 300 may include two sub-delay lines (not shown), each folding the optical path twice, such that a ratio of ΔX = 4ΔZ will maintain the optical path length. Furthermore, any number of optical repeaters or subsystems can be provided to maintain the optical path length in any number of desired or beneficial ways.

[0087] Although the second locator 108 is in Figure 8 and Figure 9 The description states that it overlaps with the incident pupil 132 (e.g., as described above relative to...). Figure 7A and Figure 7B (As discussed above), but it should be understood that the second positioner 108 can alternatively be positioned to avoid overlapping with the entrance pupil 132. For example, the folding mirror 130 can be replaced by the second positioner 108. During operation, the second positioner 108 and the scanning lens 112 can be scanned along the X direction in a manner similar to the specific example described above, and the optical path length can be maintained by moving the reverting reflector 310 synchronously relative to the repeater reflector 320.

[0088] It should be understood that the X, Y, or Z directions are arbitrarily used in the description of this specific example. For example, the optical retardation line 300 may be oriented such that the change in position between the regressor 310 and the relay reflector 320 is also in the X direction. The absolute value of the change in distance between the regressor 310 and the relay reflector 320 (and correspondingly, the absolute value of the change in distance between the optical retardation line 300 and the scanning lens 112) is the reason for the conservation of optical path length. This also applies to other specific examples described below.

[0089] D. Specific Example 4: Optical Delay Line with Polarization Beam Splitter

[0090] Figure 10 and Figure 11 The diagram illustrates the positional state of an optical relay system provided with an optical delay line (such as optical delay line 400) and a polarization beam splitter. Optical delay line 400 receives a laser energy beam 116 from a first positioner 106 and relays it to a scanning lens 112 via a folding mirror 130. In this specific example, the laser energy beam 116 initially transmitted to optical delay line 400 is linearly polarized. It should be understood that the folding mirror 130 is optional and may be omitted if the orientation of one or more other components of the laser processing apparatus 100 (e.g., first positioner 106, second positioner 108, scanning lens 112, optical delay line 400, or the like or any combination thereof) is modified to ensure that the laser energy beam 116 propagates from the first positioner 106 to the scanning lens 112. The laser energy beam 116 is thus guided to a relay pivot point 134 at or near the entrance pupil 132 of the scanning lens 112.

[0091] Specifically, the optical delay line 400 includes a polarization beam splitter 430, a delay unit 412, a reflector 410, a motion system 408 (e.g., a linear stage), and a delay line body 402. The polarization beam splitter 430, the delay unit 412 (e.g., a quarter-wave plate), and the motion system 408 are mounted on the delay line body 402, and the reflector 410 is movable by means of the motion system 408. The optical delay line 400 can be mounted within the laser processing equipment 100 to be fixed in position relative to the first positioner 106 and the scanning lens 112, or movable relative to the first positioner 106 and / or the scanning lens 112 (e.g., as discussed above regarding the optical delay line 300).

[0092] A delay unit 412 is disposed between a polarization beam splitter 430 and a reflector 410 and is configured to change the polarization of the laser energy beam transmitted through it (e.g., from linear polarization to circular polarization, or vice versa). The reflector 410 is configured to reflect the incident laser energy beam 116 back to the polarization beam splitter 430. Therefore, the polarization of the laser energy beam 116 propagating from the polarization beam splitter 430 is changed from linear to circular polarization at the delay unit 412, and the polarization of the laser energy beam 116 propagating from the reflector 410 is changed from circular to linear polarization at the delay unit 412. However, in this case, the polarization direction of the laser energy beam 116 reflected back to the polarization beam splitter 430 (i.e., from the delay unit 412) is rotated by 90 degrees relative to the polarization direction of the laser energy beam 116 propagating from the polarization beam splitter 430 (i.e., to the delay unit 412). Therefore, the laser energy beam 116 reflected back to the polarization beam splitter 430 is reflected by the polarization beam splitter 430 to the scanning lens 112 (e.g., via the folding mirror 130).

[0093] Reflector 410 is mounted on motion system 408 attached to delay line body 402, which is configured to change the position of reflector 410 relative to polarization beam splitter 430. Alternatively, polarization beam splitter 430 may be mounted on motion system 408 such that its position relative to reflector 410 is changed.

[0094] In a specific example where the scanning lens 112 is movable relative to the optical delay line 400 (e.g., the optical delay line 400 is mounted within the laser processing apparatus 100 to be fixed in position relative to the first positioner 106), when the scanning lens 112 moves relative to the first positioner 106 (e.g., in the +X direction), the reflector 410 moves relative to the polarization beam splitter 430 (e.g., in the +Z direction). Therefore, the optical path length between the scanning lens 112 and the first positioner 106 is maintained such that when the scanning lens 112 moves, the pivot point 134 of the laser energy beam remains at or near the entrance pupil 132 of the scanning lens 112. For example, refer to... Figure 10 and Figure 11 During use, the scanning lens 112 moves in the +X direction from a distance X0 relative to the optical delay line 400 (as shown in Figure 10) to a distance X1 relative to the delay line 400 (as shown in Figure 10). Figure 11 (as shown in the diagram), changing to ΔX = X1 - X0. Synchronized with the movement of the scanning lens 112, the reflector 410 moves in the +Z direction from a distance Z0 relative to the polarization beam splitter 430 (e.g., ...). Figure 10 (As shown in the image) Move to a distance Z1 relative to the polarization beam splitter 430 (e.g.) Figure 11 As shown in the diagram, the change in position is ΔZ = Z0 - Z1. In this specific example, ΔX ≈ 2ΔZ. Since the optical path is folded into two branches in the Z direction by the optical delay line 400, the original optical path length from the first positioner 106 to the scanning lens 112 is maintained when ΔX ≈ 2ΔZ.

[0095] It should be understood that the optical delay line 400 can be configured to fold the optical path between the first positioner 106 and the scanning lens 112 into any number of branches (e.g., to provide any ratio between ΔX and ΔZ). For example, the optical delay line 400 may include two sub-delay lines (not shown), each folding the optical path into two branches such that a ratio of ΔX = 4ΔZ will maintain the optical path length. Any number of optical relay systems or subsystems can be provided to maintain the optical path length in any number of desired or beneficial ways.

[0096] In the specific example discussed above, reflector 410 is provided as a zero-phase-shift reflector. However, in another specific example, reflector 410 can be provided as a reflective phase retarder, such as a half-wave reflective phase retarder configured to rotate the polarization direction of the laser energy beam 116 after reflecting it back to the polarization beam splitter 430. In this case, retarder 412 is not required. If the laser energy beam is in the UV, mid-wave infrared, or long-wave infrared range of the electromagnetic spectrum, a half-wave plate reflective phase retarder may be necessary.

[0097] Although the second locator 108 is in Figure 10 and Figure 11 The description states that it overlaps with the incident pupil 132 (e.g., as described above relative to...). Figure 7A and Figure 7B (As discussed above), but it should be understood that the second positioner 108 can alternatively be positioned to avoid overlapping with the entrance pupil 132. For example, the folding mirror 130 can be replaced by the second positioner 108. During operation, the second positioner 108 and the scanning lens 112 can be scanned in the X direction in a manner similar to the specific example described above, and the optical path length can be maintained by synchronously moving the reflector 410 relative to the polarizing beam splitter 430.

[0098] E. Specific Example 5: Zoom Optical Relay System

[0099] As discussed above, some specific examples of optical relay systems may have a fixed magnification operable to achieve a target spot size at the surface of the workpiece, while ensuring that the laser energy beam 116 propagating along beam path 114 rotates around a pivot point 134 located at or very close to the entrance pupil 132 of the scanning lens 112. However, according to other specific examples, optical relay systems may be provided that are operable to relay the beam pivot point 134 to the entrance pupil 132 of the scanning lens 112 and vary the magnification of the laser energy beam (e.g., to adjust or maintain the laser spot size at the workpiece 102). The following is a discussion of an exemplary specific example of such an optical relay system capable of varying the magnification, collimated beam output, and constant pivot point position. This optical relay system may be optically positioned downstream of one or more of the positioners in the system (e.g., after the first positioner 106 or the second positioner 108).

[0100] Figure 12 A specific example of an optical relay system 500 configured to relay the image (focal plane) of a first positioner 106 (or a second positioner 108) to the entrance pupil 132 of a scanning lens 112 is shown. In this specific example, the position of the optical relay system 500 is fixed relative to the first positioner 106 (or the second positioner 108) and the scanning lens 112. As may be described below, the position of the optical relay system 500 (or its components) may be adjusted relative to the first positioner 106, the second positioner 108, and / or the scanning lens 112.

[0101] As shown, the relay system 500 may include a first lens 502, a zoom lens assembly 510, and a second lens 506. An aperture 504 operable to restrict light entering the zoom lens assembly 510 (e.g., to allow diffraction order separation, or to further limit the angular range of the laser energy beam 116 (and its marginal rays 116') diffracted by the first locator 106 or reflected by the second locator 108) may be positioned between the first lens 502 and the zoom lens assembly 510. In the specific example illustrated, the zoom lens assembly 510 is located between the first lens 502 and the second lens 506. Although lenses 502 and 506 are... Figure 12 The lens shown is a biconvex lens, but depending on the operating requirements of the device 100, various positive lenses (e.g., planar convex lenses, positive concave-convex lenses, positive achromatic lenses, aspherical lenses and the like, or configured as biplex lenses, triple lenses or any combination thereof) may be used.

[0102] In this specific example, the zoom lens assembly 510 includes a first lens group 516 and a second lens group 522. The first lens group 516 and the second lens group 522 are separated by a fixed distance C. The first lens group 516 includes a first lens 512 and a second lens 514, and the second lens group 522 includes a first lens 518 and a second lens 520. Figure 12 In the specific example shown, the first lens group 516 and the second lens group 522 can provide a telephoto doublet lens symmetrically arranged with respect to the lateral center line 530 of the zoom lens assembly 510. In this specific example, in the first lens group 516, the first lens 512 is a plano-concave lens and the second lens 514 is a biconvex lens, and lenses 512 and 514 are separated by a distance A. In the second lens group, lens 518 is a biconvex lens and the second lens 520 is a plano-concave lens, and lenses 518 and 520 are separated by a distance B and are arranged in a mirror-symmetrical manner with respect to the plano-concave lens 512 and the biconvex lens 514 of the first lens group 516. Distance A can be adjusted by any suitable or desired method known in the art (also referred to herein as "adjustment of the first lens group 516"). Similarly, distance B can be adjusted by any suitable or desired method known in the art (also referred to herein as "adjustment of the second lens group 522").

[0103] To adjust the magnification of the optical relay system 500 (also referred to herein as the "magnification setpoint") to set or adjust the laser spot size of the laser energy beam 116, the position of the zoom lens assembly 510 within the optical relay system 500 can be set or adjusted. The position of the zoom lens assembly 510 can be manually set (e.g., by the manufacturer of the equipment 100, by the user of the equipment 100 or other operator, by an application engineer or technician responsible for developing the process or formulation for processing the workpiece 102, or similar personnel, or any combination thereof), and then fixed in place. In another specific example, the zoom lens assembly 510 can be mounted on a first positioner 524 (e.g., a linear stage, voice coil, optical mount, etc.) operable to change the position of the zoom lens assembly 510 within the optical relay system 500 (e.g., in response to one or more commands from the controller 122).

[0104] Similar to the adjustment of the position of the zoom lens assembly 510 within the optical relay system 500, the adjustment of the first lens group 516 and the second lens group 522 can be performed manually or by mounting the first lens group 516 and the second lens group 522 onto the second positioner 526 and the third positioner 528, respectively. In this specific example, when setting the magnification setpoint of the optical relay system 500, it may be necessary to adjust the first lens group 516 and the second lens group 522 to collimate the laser energy beam 116 between the first lens group 516 and the second lens group 522, thereby creating a pivot point between the lens groups 516 and 522. Furthermore, it may be necessary to adjust the first lens group 516 and the second lens group 522 to collimate the laser energy beam 116 after the second lens 506, thereby positioning the pivot point 134 at the entrance pupil 132 of the scanning lens. The first lens group 516 and the second lens group 522 can also be adjusted as needed to adjust the effective focal length of the entire optical relay system 500, thereby maintaining the position of the pivot point 134 at or near the entrance pupil 132 of the scanning lens. The adjustment of the first lens group 516 and the second lens group 522 can be performed synchronously or sequentially (in any order) with the adjustment of the position of the zoom lens assembly 510 within the optical relay system 500, or through an iterative process.

[0105] Depending on the optical performance requirements of device 100, alternative embodiments of the zoom lens assembly 510 may be used. For example, in one alternative embodiment, the distance C between the first lens group 516 and the second lens group 522 may be adjustable rather than fixed. In another embodiment, the first lens group 516 and the second lens group 522 may include various combinations of positive lenses (e.g., plano-convex lenses, positive concave-convex lenses, positive achromatic lenses, aspherical lenses, and the like, configured as biplexes, triplets, or any combination thereof) and negative lenses (e.g., biconcave lenses, plano-concave lenses, negative concave-convex lenses, negative achromatic lenses, and the like, configured as biplexes, triplets, or any combination thereof) in any order or spacing.

[0106] As described above, when adjusting the magnification setpoint of the optical relay system 500 (e.g., to adjust or maintain the size of the laser spot at workpiece 102), it may be necessary to adjust the first lens group 516 and the second lens group 522. Figures 13A to 13C The optical relay system 500 is shown in various positional states, illustrating examples of how changes in the magnification setpoint affect the size of the laser spot and the position of the pivot point 134, and how adjustments to the first lens group 516 and the second lens group 522 can adjust the position of the pivot point 134.

[0107] Figure 13A An optical relay system 500 is shown positioned between a first locator 106 (or a second locator 108) and a scanning lens 112, such that when scanning a laser energy beam 116 (e.g., diffracted by the first locator 106 or reflected by the second locator 108), a pivot point 134 is located at or near the entrance pupil 132 of the scanning lens 112. As shown, the optical relay system 500 includes a zoom lens assembly 510 positioned between a first lens 502 and a second lens 506. The first lens group 516 has a lens separation distance A, and the second lens group 522 has a lens separation distance B. In this specific example, the distance C between the first lens group 516 and the second lens group 522 is fixed. A laser spot 532 with a diameter D0 is shown below the first locator 106 (e.g., at the image plane of the first locator 106). A laser spot 532' with a diameter D1 (e.g., magnified by the optical relay system 500) is displayed below the entrance pupil 132. In this position, the magnification setpoint of the optical relay system 500 is set such that the laser spot 532 experiences a lateral magnification of M times (e.g., 1.414) from a diameter of D0 (e.g., 30 μm) to a diameter of D1 = 1.414 * D0 = 42 μm.

[0108] Figure 13BThis demonstrates that when the magnification setpoint of the optical relay system 500 has been moved toward the zoom lens assembly 510 (e.g., by means of the first lens 502), the magnification setpoint of the optical relay system 500 is demonstrated. Figure 12 When adjusting (by actuating the first locator 524 shown in the diagram). Figure 13A An example of a change in positional state is shown. In this example, the magnification setpoint M is changed from 1.414 to 1.50, causing the diameter D0 (e.g., 30 μm) of the laser spot 532 to undergo a lateral magnification to D2 = 1.50 * D0 = 45 μm. This change in the magnification setpoint causes a change in the longitudinal magnification of the image plane of the first locator 106, thereby causing a misalignment between the pivot point 134 and the entrance pupil 132.

[0109] Figure 13C exhibit Figure 13B Examples of changes in the position state of the optical relay system 500 are shown. As shown, the spacing A of the first lens group 516 (e.g., by means of...) Figure 12 The actuation of the second positioner 526 shown in the figure is adjusted to a distance A', and the second lens group 522 (e.g., by means of...) Figure 12 The actuation of the third positioner 528 shown in the figure adjusts the spacing B to the spacing B'. This adjustment causes a change in the longitudinal magnification to reposition the pivot point 134 at the entrance pupil 132, while maintaining the lateral magnification of the laser spot 532" at 45μm.

[0110] III. Conclusion

[0111] The foregoing description of specific examples and instances of the invention is not intended to be construed as limiting it. Although several specific examples and instances have been described with reference to the drawings, it will be readily apparent to those skilled in the art that numerous modifications to the disclosed specific examples and instances, as well as other specific examples, are possible without significantly departing from the novel teachings and advantages of the invention. Accordingly, all such modifications are intended to be included within the scope of the invention as defined in the claims. For example, those skilled in the art will understand that the subject matter of any sentence, paragraph, instance, or specific example may be combined with some or all of the subject matter of other sentences, paragraphs, instances, or specific examples, unless such combinations are mutually exclusive. The scope of the invention should therefore be determined by the following claims, and the equivalents of the claims are included within the scope of the invention.

Claims

1. A laser processing system comprising: A first positioner is configured to deflect a laser energy beam around a pivot point at the position of the entrance pupil of a scanning lens, wherein the scanning lens is movable relative to the first positioner; and An optical relay system configured to maintain the pivot point at the entrance pupil of the scanning lens. wherein The optical relay system is configured to move synchronously with the movement of the scanning lens, and The optical relay system is configured to laterally amplify the laser energy beam to compensate for changes in the optical path length between the optical relay system and the entrance pupil.

2. The laser processing system of claim 1, wherein the first positioner is selected from at least one of the group consisting of an AOD system and a galvanometer mirror system.

3. The laser processing system of claim 1, wherein the lateral magnification provided by the optical relay system is approximately 1.

414.

4. The laser processing system of claim 1, wherein the optical relay system is movable relative to the first locator.

5. The laser processing system of claim 1, wherein the optical relay system comprises: Optical input; A first reflector having a first reflective surface, wherein the first reflector is configured to receive the laser energy beam propagating from the first locator; Optical output; and A second reflector having a second reflective surface opposite to the first reflective surface, wherein the first reflective surface and the second reflective surface are configured to relay the laser energy beam received at the first reflector from the optical input to the optical output.

6. The laser processing system of claim 5, wherein the optical relay system further comprises: A first lens, configured and positioned to focus the laser energy beam within the optical relay system; and A second lens, configured and positioned to focus the laser energy beam exiting the optical relay system. The first lens and the second lens are configured to amplify the laser energy beam.

7. The laser processing system of claim 6, wherein the first lens is configured to focus the laser energy beam at a point separate from the first reflective surface and the second reflective surface.

8. The laser processing system of claim 5, further comprising a stage coupled to the optical relay system, wherein the stage is operable to change the position of the optical relay system relative to at least one or a combination thereof selected from the scanning lens and the first positioner.

9. The laser processing system of claim 1, further comprising a second positioner disposed between the optical relay system and the scanning lens.

10. The laser processing system of claim 9, wherein the second positioner is selected from at least one of the group consisting of a galvanometer, an AOD system, a fast control mirror, and a rotating polygonal mirror.

Images