Optical relay system, method of use thereof, and method of manufacturing thereof

Abstract

Numerous embodiments of optical relay systems are disclosed. In one embodiment, a laser processing apparatus includes an optical relay system configured to correct beam placement errors by maintaining an optical path length of a laser energy beam between a first positioner and a scan lens. In other embodiments, the optical relay system can include a first lens, a second lens, and a zoom lens assembly disposed between the first and second lenses. The zoom lens assembly includes a first lens group and a second lens group. The zoom lens assembly can be movable relative to the first and second lenses (e.g., mounted on a positioner such as a motion stage). The distance between the lenses in the first lens group and the distance between the lenses in the second lens group can be fixed or variable.

Description

Cross-reference to related applications

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 122,573, filed December 8, 2020, the contents of which are hereby incorporated by reference in their entirety.

Technical Field

[0002] The embodiments described herein generally relate to laser processing apparatuses, optical relay systems, their components, and methods for operating the same. Background

[0003] Laser processing systems and apparatuses are used in a variety of applications such as the processing of printed circuit boards (PCBs), additive manufacturing methods, and the like. Many laser processing systems include a scan lens for focusing a laser energy beam onto a workpiece and a positioner for moving the focused laser energy beam relative to the material being processed. In some laser processing systems, the scan lens can be moved while the positioner remains stationary, resulting in a change in the optical path length between the scan lens and the positioner in response to the movement of the scan lens. The change in the optical path length can cause the laser energy beam to rotate about a turning point located outside the entrance pupil of the scan lens (referred to herein as the "scan lens entrance pupil" or more simply "SLEP"). The position of the turning point outside the SLEP can cause telecentric errors, beam distortion at the workpiece, and unwanted beam clipping at the scan lens entrance pupil. Summary

[0004] One embodiment of the present invention includes a first positioner configured to deflect a laser energy beam around a pivot point, a scan lens movable relative to the first positioner, and an optical relay system configured to relay the pivot point to the scan lens in response to the movement of the scan lens, wherein the scan lens can be characterized as a laser processing apparatus movable relative to the optical relay system. The first positioner may be provided as an AOD system or a galvanometer mirror system. The optical relay system may be movable relative to the scan lens and / or the first positioner. The optical relay system includes an optical input, a first reflector having a first reflective surface and positioned to receive a laser energy beam propagating from the first positioner, an optical output, and a second reflector having a second reflective surface opposite the first reflective surface, wherein the first and second reflective surfaces may be positioned and configured to relay the laser energy beam received from the optical input at the first reflector to the optical output. The first and second reflective surfaces may be substantially parallel to each other. The first lens may be installed at the optical input. The second lens may be installed at the optical output. The first positioner (e.g., AOD system and galvanometer mirror system) may be movable relative to the optical relay system. A linear stage may be coupled to the first positioner. This stage may be able to change the position of the first positioner relative to the optical relay system.

[0005] In other embodiments, the optical relay system includes a first lens positioned and configured to focus a laser energy beam within the optical relay system, and a second lens positioned and configured to focus the laser energy beam leaving the optical relay system, wherein the first and second lenses may be configured to magnify the laser energy beam. The first lens may be configured to focus the laser energy beam to a point away from the first and second reflective surfaces. A stage may be connected to the optical relay system. This stage may be able to change the position of the optical relay system relative to a scanning lens, a first positioner, or a combination thereof.

[0006] In other embodiments, the laser processing apparatus may further include a second positioner positioned between the optical relay system and the scanning lens. The second positioner may be a galvanometer, an AOD system, a fast steering mirror, or a rotating polyhedron mirror.

[0007] In other embodiments, the optical relay system may include a first lens, a second lens, and a zoom lens assembly positioned between the first and second lenses, comprising a first lens group and a second lens group, each containing a plurality of lenses. The first and second lens groups may be telephoto double lenses arranged symmetrically with respect to the transverse centerline of the zoom lens assembly. The zoom lens assembly may be movable relative to at least one of the first and second lenses (e.g., mounted on a first positioner such as a motion stage). The first and second lenses may be positive lenses, planar convex lenses, biconvex lenses, or positive meniscus lenses, or any combination thereof. The distances between the lenses of the first lens group and the distances between the lenses of the second lens group may be fixed or variable. The first lens group may be mounted on a second positioner (e.g., a motion stage) configured to adjust the distances between the lenses of the first lens group. The second lens group may be mounted on a third positioner (e.g., a motion stage) configured to adjust the distance between the lenses of the second lens group. [Brief explanation of the drawing]

[0008] [Figure 1-3] Figures 1 to 3 are schematic diagrams illustrating various spatial states of a laser processing system. [Figure 4] Figure 4 schematically shows a laser processing apparatus according to one embodiment. [Figure 5-6] Figures 5 and 6 show different positional states of an optical relay system according to one embodiment. [Figures 7A-7B]Figures 7A and 7B show different positional states of other embodiments of the optical relay system. In Figures 7A and 7B, the optical relay system is shown in a longitudinal section. [Figure 8-9] Figures 8 and 9 show different positional states of other embodiments of the optical relay system. [Figure 10-11] Figures 10 and 11 show different positional states of other embodiments of the optical relay system. [Figure 12] Figure 12 shows another embodiment of the optical relay system. [Figure 13A-13C] Figures 13A to 13C show different positional states of the embodiment of the optical relay system shown in Figure 12. Detailed explanation

[0009] The following describes examples of embodiments with reference to the attached drawings. Unless explicitly stated, the sizes, positions, and distances between components, features, and elements in the drawings are not necessarily to scale and are exaggerated for ease of understanding. Similar numbers throughout the drawings represent similar elements. Therefore, identical or similar numbers may be mentioned by reference to other drawings even if they are not mentioned or described in the corresponding drawings. Furthermore, elements without reference numbers may also be mentioned by reference to other drawings.

[0010] The terms used in this specification are for the sole purpose of describing specific exemplary embodiments and are not intended to be limiting. Unless otherwise specifically defined, all terms used herein (including technical and scientific terms) have the same meaning as generally understood by those skilled in the art. Where used herein, singular nouns are intended to include plural nouns unless the context explicitly indicates otherwise. Furthermore, the terms “equipped with” and / or “equipped with” should be understood to identify the presence of a described feature, integer, step, operation, element, and / or component, but not to exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. Unless otherwise specifically indicated, where a range of values ​​is given, that range includes the upper and lower limits, as well as the sub-range between the upper and lower limits of that range. Unless otherwise specifically indicated, terms such as “first” and “second” are used solely to distinguish elements from one another. For example, one node may be called the “first node,” and similarly another node may be called the “second node,” or vice versa.

[0011] Unless otherwise specified, “approximately,” “around,” and “about” mean that quantities, sizes, proportions, parameters, and other quantities and characteristics are not, and do not need to be, exact, and may be approximate, and may be larger or smaller, as needed, or to reflect tolerances, conversion factors, rounding, measurement errors, and other factors known to those skilled in the art. In this specification, spatially relative terms such as “below,” “down,” “below,” “up,” and “above” may be used to facilitate explanation when describing the relationship between one element or feature and another element or feature, as shown in the figures. It should be understood that spatially relative terms are intended to include different orientations in addition to the orientations shown in the figures. For example, an element described as being “below” or “below” another element or feature would, if the object in the figure were inverted, face “above” the other element or feature. Thus, the exemplary term “below” may include both upward and downward orientations. If the object is facing a different direction (for example, if it is rotated 90 degrees or is in a different direction), the spatially relative descriptors used herein may be interpreted accordingly.

[0012] Section headings used herein are for organizational purposes only, unless otherwise specified, and should not be construed as limiting the subject matter discussed. It will be understood that many different forms, embodiments, and combinations are conceivable without departing from the spirit and teachings of this disclosure, and that this disclosure should not be construed as limiting to the examples of embodiments described herein. Rather, these examples and embodiments are provided to fully convey the scope of this disclosure to those skilled in the art, as it is complete and all-encompassing.

[0013] I. Overview Figures 1 to 3 are schematic diagrams illustrating various spatial states of a laser processing system. Referring to Figure 1, the laser energy beam 10 is deflected by a positioner 12 and propagates toward the scan lens 14 via a folding mirror 16. Although not shown, relay optics are typically included to relay the pivot point of the positioner 12 to the entrance pupil 18 of the scan lens 14. As shown, the image of the beam from the positioner 12 pivots around a virtual pivot point 20 in the entrance pupil 18 of the scan lens 14, thereby producing acceptable telecentricity for the ray exiting the scan lens 14.

[0014] Referring to Figure 2, the scan lens 14 and folding mirror 16 shown in Figure 1 are moved away from the positioner 12, which increases the optical path length between the positioner 12 and the scan lens 14. By increasing the optical path length, the virtual pivot point 20 moves away from the entrance pupil 18 and the scan lens 14 (for example, in this case, it is on or near the surface of the folding mirror 16). This distance of the virtual pivot point 20 from the scan lens 14 can worsen the telecentricity of the light rays emitted from the scan lens 14, potentially leading to positional errors, particularly regarding the spot position on the workpiece.

[0015] Referring to Figure 3, the scan lens 14 and folding mirror 16 shown in Figure 1 have been moved towards the positioner 12, thereby shortening the optical path length between the positioner 12 and the scan lens 14. By shortening the optical path length, the virtual pivot point 20 moves away from the entrance pupil 18 and towards the scan lens 14 (and in this example, even beyond the scan lens 14). Moving the virtual pivot point 20 towards the scan lens 14 in this way worsens telecentricity and can cause positional errors regarding the spot position on the workpiece, as described above. Furthermore, such movement of the virtual pivot point 20 can cause undesirable beam clipping by the entrance pupil 18, reducing the useful deflection range of the positioner 12.

[0016] Figure 4 schematically shows a laser processing apparatus according to one embodiment of the present invention.

[0017] Referring to the embodiment shown in Figure 4, a laser processing apparatus 100 (hereinafter also simply referred to as the “apparatus”) for processing a workpiece 102 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 scan lens 112. The scan lens 112 and the second positioner 108 may be integrated into a scan head 120, which will be described in more detail below.

[0018] The laser energy transmitted through the scan lens 112 along the beam path 114 propagates along the beam axis 118 so as to irradiate the workpiece 102. The laser energy propagating along the beam axis 118 may 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 may be characterized as the shape (i.e., cross-sectional shape; also referred herein as “spot shape”) of the laser energy beam propagating along the beam axis 118 (or beam path 114). Such shapes may be circular, elliptical, square, rectangular, triangular, hexagonal, ring-shaped, or any other shape. As used herein, the term “spot size” means the diameter or maximum spatial width of the laser energy beam irradiating a region of the workpiece 102 that is at least partially processed by the irradiated laser energy beam at the point where the beam axis 118 intersects (also called the “process spot,” “spot location,” or simply “spot”). For the purposes of this specification, the spot size is defined as the light intensity from the beam axis 118, which is 1 / e of the light intensity at the beam axis 118. 2It is measured as the radial or transverse distance to where it drops down to. Generally, the spot size of a laser energy beam is smallest at the beam waist. When irradiated onto the workpiece 102, the laser energy in the beam can be characterized as hitting the workpiece 102 with a spot size in the range of 2 μm to 200 μm. However, it can be understood that the spot size can be smaller than 2 μm or larger than 200 μm. Thus, a laser energy beam irradiated onto the workpiece 102 can have a spot size greater than, smaller 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 any value between these values.

[0019] Generally, the positioners described above (e.g., the first positioner 106, the second positioner 108, and the third positioner 110) are configured to change the relative position between the spot and the workpiece 102. From the following description, it should be understood that if the device 100 includes the first positioner 106 and optionally the third positioner 110, then including the second positioner 108 is optional. Similarly, if the device 100 includes the first positioner 106 and optionally the second positioner 108, then including the third positioner 110 is optional.

[0020] Also, when the laser energy beam propagates along the beam path 114, the apparatus 100 may include one or more other optical components for focusing, expanding, collimating, shaping, polarizing, filtering, splitting, combining, cropping, absorbing, or modifying and adjusting the laser energy beam (e.g., beam traps, beam expanders, beam shapers, beam splitters, apertures, filters, collimators, lenses, mirrors, prisms, polarizers, phase retarders, diffractive optical elements (commonly known as DOE in the art), refractive optical elements (commonly known as ROE in the art), etc., or any arbitrary combination thereof). Optical components such as beam expanders, lenses, beam splitters, prisms, dichroic filters, windows, waveplates, DOE, ROE, etc. are collectively referred to herein as "transmission-type optical components" as long as they are composed of a set of transparent materials intended to transmit the incident laser energy beam (which may be coated with an anti-reflection coating or the like as required). As used herein, the assembly of the positioner and other optical components is considered to constitute a "beam path assembly" when incorporated together into the laser processing apparatus 100.

[0021] A. Laser source In one embodiment, the laser source 104 can generate laser pulses. Therefore, the laser source 104 may include a pulsed laser source, a CW laser source, a QCW laser source, a burst-mode laser, or any combination thereof. If the laser source 104 includes a QCW laser source or a CW laser source, the laser source 104 may operate in pulsed mode or in non-pulsed mode, but may further include a pulse gating unit (e.g., an acousto-optic (AO) modulator (AOM), a beam chopper, etc.) that temporally modulates the beam of laser radiation output from the QCW laser source or CW laser source. Although not shown, the apparatus 100 may optionally include one or more harmonic generating crystals (also known as "wavelength conversion crystals") configured to convert the wavelength of light output by the laser source 104. However, in other embodiments, the laser source 104 may be provided as a QCW laser source or a CW laser source and may not include a pulse gating unit. Thus, the laser source 104 can be broadly characterized as capable of generating a laser energy beam that can be represented as a series of laser pulses that can then propagate along the beam path 114, or as a continuous or quasi-continuous laser beam. Although many embodiments described herein refer to laser pulses, it should be understood that a continuous or quasi-continuous beam can be used as an alternative or additional method where appropriate or necessary.

[0022] The laser energy output by the laser source 104 can have one or more wavelengths in the ultraviolet (UV), visible light, or infrared (IR) regions of the electromagnetic spectrum. The laser energy in the UV range of the electromagnetic spectrum can have one or more wavelengths in the range from 10 nm (or around it) to 385 nm (or around it), such as 100 nm, 121 nm, 124 nm, 157 nm, 200 nm, 334 nm, 337 nm, 351 nm, 380 nm, or wavelengths between any of these values. The laser energy in the visible green light region of the electromagnetic spectrum can have one or more wavelengths in the range from 500 nm (or around it) to 560 nm (or around it), such as 511 nm, 515 nm, 530 nm, 532 nm, 543 nm, 568 nm, or wavelengths between any of these values. The laser energy in the IR region of the electromagnetic spectrum can have one or more wavelengths in the range from 750 nm (or around it) to 15 μm (or around it), such as from 600 nm to 1000 nm, 752.5 nm, from 780 nm to 1060 nm, 799.3 nm, 980 nm, 1047 nm, 1053 nm, 1060 nm, 1064 nm, 1080 nm, 1090 nm, 1152 nm, from 1150 nm to 1350 nm, 1540 nm, from 2.6 μm to 4 μm, from 4.8 μm to 8.3 μm, 9.4 μm, 10.6 μm, or wavelengths between any of these values.

[0023] When the laser energy beam is represented as a series of laser pulses, the laser pulses output by the laser source 104 may have a pulse width or pulse duration (i.e., based on the full width at half maximum (FWHM) of the optical power in the pulse with respect to time) in the range of 10 fs to 900 ms. However, it can be understood that the pulse duration may be shorter than 10 fs or longer than 900 ms. Thus, at least one laser pulse output by the laser source 104 is 10fs, 15fs, 30fs, 50fs, 100fs, 150fs, 200fs, 300fs, 500fs, 600fs, 750fs, 800fs, 850fs, 900fs, 950fs, 1ps, 2ps, 3ps, 4ps, 5ps, 7ps, 10ps, 15ps, 25ps, 50ps, 75ps, 100ps, 200ps, 500ps, 1ns, 1.5ns, 2ns, 5ns, 10ns, 20ns, 50ns, 10 The pulse duration can be shorter than, longer than, or equal to, a value between these values, such as 0ns, 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.

[0024] The laser pulses output by the laser source 104 can have an average power in the range of 5mW to 50kW. However, it can be understood that the average power may be lower than 5mW or higher than 50kW. Thus, the laser pulses output by the laser source 104 can have an average power of 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 an average power lower than, higher than, or equal to any of these values.

[0025] Laser pulses can be output by the laser source 104 at pulse repetition rates in the range of 5 kHz to 5 GHz. However, it can be understood that the pulse repetition rate may be lower than 5 kHz or higher than 5 GHz. Thus, laser pulses can be output by the laser source 104 at pulse repetition rates lower than, higher than, or equal to, values ​​in the range of 5 kHz, 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 values ​​in between these values.

[0026] In addition to wavelength, average power, and pulse duration and pulse repetition rate when the laser energy beam is expressed as a series of laser pulses, the laser energy beam irradiated onto the workpiece 102 can be characterized by one or more other properties such as pulse energy and peak power. Such properties include sufficient light intensity (W / cm²) to process the workpiece 102 (for example, to form one or more features). 2 (measured in) and fluence (J / cm²) 2 To irradiate the process spot of the workpiece 102 (as measured by, for example, the wavelength, pulse duration, average power, pulse repetition rate, etc.), it can be selected (for example, based on one or more other characteristics as needed, such as wavelength, pulse duration, average power, pulse repetition rate, etc.).

[0027] Examples of laser types that may characterize the laser source 104 include 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, passive mode-locked solid bulk or fiber lasers, dye lasers, mode-locked diode lasers, pulsed lasers (e.g., ms pulsed lasers, ns pulsed lasers, ps pulsed lasers, fs pulsed lasers), CW lasers, QCW lasers, etc., or any combination thereof. Depending on the configuration, a gas laser (e.g., a carbon dioxide laser, etc.) may be configured to operate in one or more modes (e.g., CW mode, QCW mode, pulsed mode, or any combination thereof). Specific examples of laser sources that may be provided as laser source 104 include BOREAS, HEGOA, SIROCCO, or CHINOOK series lasers manufactured by EOLITE, PYROFLEX series lasers manufactured by PYROPHOTONICS, PALADIN Advanced 355 or DIAMOND series (e.g., DIAMOND E series, G series, J-2 series, J-3 series, J-5 series), FLARE NX series, MATRIX QS DPSS series, MEPHISTO Q series, AVIA LX series, AVIA NX series, RAPID NX series, HYPERRAPID NX series, RAPID series, HELIOS series, FIDELITY series, MONACO series, OPERA series, or RAPID FX series lasers, SPECTRA Lasers from the ASCEND series, EXCELSIOR series, EXPLORER series, HIPPO series, NAVIGATOR series, QUANTA-RAY series, QUASAR series, SPIRIT series, TALON series, or VGEN series manufactured by PHYSICS, lasers from the PULSTAR series or FIRESTAR series manufactured by SYNRAD, and lasers from the TRUFLOW series manufactured by TRUMPF (for example, TRUFLOWLasers (2000, 2600, 3000, 3200, 3600, 4000, 5000, 6000, 6000, 8000, 10000, 12000, 15000, 20000), TRUCOAX series lasers (e.g., TRUCOAX 1000), or TRUDISK series, TRUPULSE series, TRUDIODE series, TRUFIBER series, or TRUMICRO series lasers, FCPAμJEWEL or FEMTOLITE series lasers manufactured by IMRA AMERICA, TANGERINE and SATSUMA series lasers (and MIKAN and T-PULSE series oscillators) manufactured by AMPLITUDE SYSTEMES, IPG One or more laser sources include lasers from the CL series, CLPF series, CLPN series, CLPNT series, CLT series, ELM series, ELPF series, ELPN series, ELPP series, ELR series, ELS series, FLPN series, FLPNT series, FLT series, GLPF series, GLPN series, GLR series, HLPN series, HLPP series, RFL series, TLM series, TLPN series, TLR series, ULPN series, ULR series, VLM series, VLPN series, YLM series, YLPF series, YLPN series, YLPP series, YLR series, YLS series, FLPM series, FLPMT series, DLM series, BLM series, or DLR series (including, for example, GPLN-100-M, GPLN-500-QCW, GPLN-500-M, GPLN-500-R, GPLN-2000-S, etc.) manufactured by PHOTONICS, or similar lasers, or any combination thereof.

[0028] B. First positioner The first positioner 106 is positioned, located, or installed in the beam path 114 and can diffract, reflect, refract, or similarly deflect, or any combination thereof (i.e., "deflect" the laser pulses) the laser pulses generated by the laser source 104 to deflect or move the beam path 114 (for example, relative to the scan lens 112), thereby deflecting or moving the beam axis 118 relative to the workpiece 102. Generally, the first positioner 106 is capable of moving the beam axis 118 relative to the workpiece 102 along the X-axis (or X direction), the Y-axis (or Y direction), or a combination thereof. Although not shown, the X-axis (or X direction) can be understood to mean an axis (or direction) perpendicular to the illustrated Y-axis (or Y direction) and Z-axis (or Z direction).

[0029] Generally, the first positioner 106 can be provided as a galvanometer mirror system, an AO deflector (AOD) system, an electro-optical (EO) deflector (EOD) system, a fast steering mirror (FSM) system, or any combination thereof. The AOD in an AOD system generally includes an AO cell formed from materials such as crystalline germanium (Ge), gallium arsenide (GaAs), chalcite (PbMoO4), tellurium dioxide (TeO2), quartz, glassy SiO2, arsenic trisulfide (As2S3), lithium niobate (LiNbO3), or any combination thereof. The EOD in an EOD system generally includes an EO cell formed from lithium niobate, potassium tantalite niobate, or the like. Insofar as the AO cell and EO cell are configured to transmit the incident laser energy beam, they can be considered a type of transmissive optical component.

[0030] C. Second position The second positioner 108 is positioned in the beam path 114 and can diffract, reflect, refract, or similarly deflect the laser pulse generated by the laser source 104 and passing through the first positioner 106, or any combination thereof (i.e., "deflect" the laser pulse), thereby deflecting or moving the beam path 114 (for example, relative to the scan lens 112), and consequently deflecting or moving the beam axis 118 relative to the workpiece 102. Generally, the second positioner 108 can move the beam axis 118 relative to the workpiece 102 along the X-axis (or X direction), the Y-axis (or Y direction), or a combination thereof.

[0031] From the above perspective, it should be understood that the second positioner 108 may be a microelectromechanical system (MEMS) mirror or mirror array, an AOD system, an electro-optical deflector (EOD) system, a fast steering mirror (FSM) element (incorporating, for example, a piezoelectric actuator, an electrostrictive actuator, a voice coil actuator, etc.), a galvanometer mirror system, a resonant scanning mirror system, a rotating multi-face scanner, or something similar, or any combination thereof.

[0032] In one embodiment, the second positioner 108 may be provided as a two-axis galvanometer mirror system including two galvanometer mirror components: a first galvanometer mirror component (e.g., an X-axis galvanometer mirror component) configured to move the beam axis 118 along the X-axis relative to the workpiece 102, and a second galvanometer mirror component (e.g., a Y-axis galvanometer mirror component) configured to move the beam axis 118 along the Y-axis relative to the workpiece 102. However, in other embodiments, the second positioner 108 may be provided as a galvanometer mirror system including only a single galvanometer mirror component configured to move the beam axis 118 along both the X-axis and the Y-axis relative to the workpiece 102. In yet another embodiment, the second positioner 108 may be provided as a rotating polyhedron mirror system, etc. Thus, it can 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.

[0033] D. Third position In the illustrated embodiment, the third positioner 110 includes one or more linear stages (for example, each capable of giving the workpiece 102 translational movement along the X, Y, and / or Z directions) or any combination thereof, arranged and configured to produce relative movement between the workpiece 102 and the scan lens 112, and as a result, relative movement between the workpiece 102 and the beam axis 118, or one or more rotary stages (for example, each capable of giving the workpiece 102 rotational movement about an axis parallel to the X, Y, and / or Z directions), or any combination thereof. According to embodiments described herein, although not shown, the third positioner 110 includes one or more stages configured and adapted to produce relative movement between the scan lens 112 and the first positioner 106.

[0034] In terms of the configurations described herein, it should be understood that the movement of the process spot relative to the workpiece 102 (for example, performed by the first positioner 106 and / or the second positioner 108) can be superimposed on the movement of the workpiece 102 or the scan lens 112 performed by the third positioner 110.

[0035] In the illustrated embodiment, the third positioner 110 is operable to move the workpiece 102. However, in other embodiments, the third positioner 110 may be positioned and operable to move the scan head 120 and, optionally, one or more components such as the first positioner 106, while keeping the workpiece 102 stationary. In yet another embodiment, the third positioner 110 may be provided as a so-called "split-axis" positioning system in which the scan lens 112 and, optionally, one or more other components such as the first positioner 106 and the second positioner 108 are transported by one or more linear or rotary stages (e.g., mounted on a frame or gantry), and the workpiece 102 is transported by one or more other linear or rotary stages. If the third positioner 110 is provided as a “split axis” positioning system, the third positioner 110 includes one or more operable linear or rotary stages arranged to move one or more components such as a scan head 120, and one or more operable linear or rotary stages arranged to move a workpiece 102. For example, the third positioner 110 may include a Y-stage for moving the workpiece 102 along the Y-direction and an X-stage for moving the scan head along the X-direction. Examples of split-axis positioning systems that may be usefully or conveniently used in apparatus 100 include any of those disclosed in U.S. Patents No. 5,751,585, 5,798,927, 5,847,960, 6,606,999, 7,605,343, 8,680,430, 8,847,113, or in U.S. Patent Application Publication 2014 / 0083983, or any combination thereof. Each of these documents is incorporated herein by reference in its entirety.

[0036] In one embodiment, the third positioner 110 includes a Z-stage, where the Z-stage may be positioned and configured to move the workpiece 102 along the Z-direction. In this case, the Z-stage may be transported by one or more of the other stages described above for moving or positioning the workpiece 102, or transport one or more of the other stages described above for moving or positioning the workpiece 102, or any combination thereof. In another embodiment, the third positioner 110 includes a Z-stage, where the Z-stage may be positioned and configured to move the scan head along the Z-direction. Thus, when the third positioner 110 is provided as a split-axis positioning system, the Z-stage may transport the X-stage, or be transported by the X-stage. By moving the workpiece 102 or the scan head along the Z-direction, the spot size on the workpiece 102 can be changed.

[0037] In yet another embodiment, one or more components, such as the first positioner 106, the second positioner 108, and the scan lens 112, may be transported by a multi-axis articulated robot arm (e.g., a 2-axis, 3-axis, 4-axis, 5-axis, or 6-axis arm). In such an embodiment, the second positioner 108 and / or the scan lens 112 may be transported by the end effector of the robot arm, if necessary. In yet another embodiment, the workpiece 102 may be transported directly on the end effector of the multi-axis articulated robot arm (i.e., without the third positioner 110). In yet another embodiment, the third positioner 110 may be transported on the end effector of the multi-axis articulated robot arm.

[0038] E. Scan Lens Generally, the scan lens 112 (for example, provided as either a simple lens or a composite lens) is typically configured to focus a laser energy beam directed along the beam path to generate a beam waist that may be located at or near a desired process spot. The scan lens 112 may be provided as an f-theta lens, a telecentric lens, an axicon lens (in which case a series of beam waists are generated, resulting in multiple process spots offset from each other along the beam axis), or any combination thereof. The scan lens 112 may be provided as a non-telecentric lens (as illustrated), a f-theta lens, a telecentric lens, an axicon lens (in which case a series of beam waists are generated, resulting in multiple process spots offset from each other along the beam axis 118), or any combination thereof.

[0039] In one embodiment, the scan lens 112 is provided as a fixed focal length lens and is connected to a scan lens positioner (e.g., a lens actuator, not shown) that can move the scan lens 112 (e.g., to change the position of the beam waist along the beam axis). For example, the lens actuator may be provided as a voice coil capable of linearly translating the scan lens 112 along the Z direction. In this case, the lens actuator can be considered as a component of the third positioner 110 described above. Furthermore, the fixed focal length lens may be formed from materials such as fused silica, optical glass, zinc selenide, zinc sulfide, germanium, gallium arsenide, or magnesium fluoride. In other embodiments, the scan lens 112 is provided as a variable focal length lens (e.g., a zoom lens, or a so-called "liquid lens" incorporating technology currently offered by COGNEX, VARIOPTIC, etc.) that can be operated (e.g., via a lens actuator) to change the position of the beam waist along the beam axis 118. By changing the position of the beam waist along the beam axis 118, the spot size on the workpiece 102 can be changed.

[0040] As described above, in one embodiment, the scan lens 112 and the second positioner 108 are integrated into a common scan head 120. Thus, in embodiments in which the device 100 includes a lens actuator, the lens actuator may be connected to the scan lens 112 (for example, to enable the movement of the scan lens 112 relative to the second positioner 108 within the scan head 120). Alternatively, the lens actuator may be connected to the scan head 120 and operable to make the scan head itself movable, in which case the scan lens 112 and the second positioner 108 move together. In either case, the lens actuator can be considered here as a component of the third positioner 110 described above. In other embodiments, the scan lens 112 and the second positioner 108 are integrated into different housings (for example, so that the housing into which the scan lens 112 is integrated is movable relative to the housing into which the second positioner 108 is integrated).

[0041] F. Controller Generally, the device 100 includes one or more controllers, such as a controller 122, for controlling or facilitating the control and operation of the device 100. In one embodiment, the controller 122 is communicatively connected (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 any combination thereof) to one or more components of the device 100, such as a laser source 104, a first positioner 106, a second positioner 108, a third positioner 110, a lens actuator, a scanning lens 112 (if provided as a variable focal length lens), and fixtures, so that these components operate in response to one or more control signals output by the controller 122.

[0042] For example, the 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 perform relative movement between the beam axis and the workpiece, and to generate relative motion 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 so that two positioners (e.g., the first positioner 106 and the second positioner 108, the first positioner 106 and the third positioner 110, the second positioner 108 and the third positioner 110) or three positioners simultaneously generate relative movement between the process spot and the workpiece 102 (thus generating a “composite relative movement” between the beam axis and the workpiece). Of course, it is also possible to control only one positioner (e.g., a first positioner 106, a second positioner 108, or a third positioner 110) to cause a relative movement between the process spot and the workpiece 102 at any given time (thus causing a "non-compound relative movement" between the beam axis and the workpiece).

[0043] Other examples of operations that can be controlled to perform on one or more of the above-mentioned components include those disclosed in U.S. Patents No. 5,751,585, 5,847,960, 6,606,999, 8,680,430, and 8,847,113, or U.S. Patents No. 4,912,487, 5,633,747, 5,638,267, 5,917,300, and 6,3 No. 14,463, No. 6,430,465, No. 6,600,600, No. 6,606,998, No. 6,816,294, No. 6,947,454, No. 7,019,891, No. 7,027,199 , No. 7,133,182, No. 7,133,186, No. 7,133,187, No. 7,133,188, No. 7,244,906, No. 7,245,412, No. 7,259,354, No. 7,611, As disclosed in U.S. Patent Publications No. 745, 7,834,293, 8,026,158, 8,076,605, 8,288,679, 8,404,998, 8,497,450, 8,648,277, 8,896,909, 8,928,853, and 9,259,802, or in U.S. Patent Publications No. 2014 / 0026351, 2014 / 0196140, and 2 Examples include operations, functions, processes, and methods disclosed in Patent Nos. 014 / 0263201, 2014 / 0263212, 2014 / 0263223, 2014 / 0312013, or in German Federal Patent No. DE102013201968B4, or in International Patent Publication No. WO2009 / 087392, or any combination thereof. Each of these documents is incorporated herein by reference in its entirety.In other examples, the controller 122 may control the operation of any positioner, including one or more AODs (e.g., in one embodiment, a first positioner 106, a second positioner 108, or a combination thereof), for changing the spot shape or spot size of the laser energy beam irradiated onto the process spot (e.g., by chirpening an RF signal applied to one or more ultrasonic converters of one or more AODs, by applying a spectrally shaped RF signal to one or more ultrasonic converters of one or more AODs, or by similar methods, or by any combination thereof), as disclosed in, for example, International Patent Publication WO2017 / 044646A1. The above publication is incorporated herein by reference in its entirety. The applied RF signal may be chirp linearly or nonlinearly in a desired or preferred manner. For example, the applied RF signal may be chirp at a first speed and then chirp at a second speed to diffract the laser energy beam passing through the AO cell in two different ways. In this case, the first speed may be slower or faster than the second speed.

[0044] Generally, the controller 122 includes one or more processors capable of generating the aforementioned control signals when executing instructions. The processors may be provided as programmable processors capable of executing instructions (e.g., one or more general-purpose computer processors, microprocessors, digital signal processors, or any combination thereof). Instructions executable by the processors may be implemented as software, firmware, or in any preferred form of circuitry, including programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), field-programmable object arrays (FPOAs), application-specific integrated circuits (ASICs) (including digital circuits, analog circuits, and mixed analog / digital circuits), or any combination thereof. Instruction execution may occur on a single processor, distributed across multiple processors, in parallel across multiple processors within a single device or across a network of devices, or in similar manner, or in any combination thereof.

[0045] In one embodiment, the controller 122 includes a tangible medium such as computer memory accessible by the 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 disks, volatile or non-volatile semiconductor memory (e.g., RAM, ROM, NAND flash memory, NOR flash memory, SONOS memory, etc.), and may be locally accessible, remotely accessible (e.g., via a network), or a combination thereof. Generally, instructions may be stored as computer software (e.g., executable code, files, instructions, library files, etc.). Such computer software can be written in, for example, C, C++, Visual Basic, Java, Python, Tel, Perl, Scheme, Ruby, assembly language, hardware description languages ​​(e.g., VHDL, VERILOG, etc.) and can be easily created by those skilled in the art from the descriptions provided herein. Computer software is typically stored in one or more data structures transmitted by computer memory.

[0046] 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 the laser source 104, the first positioner 106, the second positioner 108, the third positioner 110, the lens actuator, the scan lens 112 (if provided as a variable focal length lens), and the fixture, in order to control such components. Thus, one or more components, such as the laser source 104, the first positioner 106, the second positioner 108, the third positioner 110, the lens actuator, the scan lens 112 (if provided as a variable focal length lens), and the fixture, can also be considered to include any suitable drivers known in the art. Each driver typically includes an input to which a controller 122 is communicatively coupled, and the controller 122 is capable of generating one or more control signals (e.g., trigger signals). These control signals may be transmitted to the inputs of one or more drivers associated with one or more components of the device 100. Thus, components such as the laser source 104, the first positioner 106, the second positioner 108, the third positioner 110, the lens actuator, the scan lens 112 (if provided as a variable focal length lens), and the fixtures are configured to respond to control signals generated by the controller 122.

[0047] Although not shown, one or more additional controllers (e.g., component-specific controllers) may, as needed, be communicably connected to the inputs of drivers communicably connected to (and associated with) components such as the laser source 104, the first positioner 106, the second positioner 108, the third positioner 110, the lens actuator, the scan lens 112 (if provided as a variable focal length lens), and the fixture. In this embodiment, each component-specific controller may be communicably connected to controller 122 and capable of generating one or more control signals (e.g., trigger signals) in response to one or more control signals received from controller 122. These one or more control signals may then be transmitted to the inputs of drivers communicably connected to it. In this embodiment, the component-specific controllers may be operable in the same manner as described with respect to controller 122.

[0048] In other embodiments where one or more component-specific controllers are provided, a component-specific controller associated with a component (e.g., a laser source 104) may be communicatively connected to a component-specific controller associated with another component (e.g., a first positioner 106). In this embodiment, one or more of the component-specific controllers may generate one or more control signals (e.g., trigger signals) in response to one or more control signals received from one or more other component-specific controllers.

[0049] II. Embodiment to resolve misplacement of the pivot point relative to SLEP One or more components of the third positioner 110 are configured as described above, making the scan lens 112 movable relative to the first positioner 106. Therefore, the optical path length between the scan lens 112 and the first positioner 106 is variable. Below, exemplary embodiments that can be used to compensate for the movement of the scan lens 112 relative to the first positioner 106 in order to ensure that the laser energy beam propagating along the beam path 114 rotates about a pivot point located at or at least very close to the entrance pupil of the scan lens 112 are described.

[0050] A. Embodiment 1: First positioner driven by an actuator Figures 5 and 6 show embodiments of a first positioner 106 driven by an actuator. As shown in Figure 5, the first positioner 106 is coupled to an actuator 150 (e.g., a linear stage), and a fixed relay optical component 126 is positioned in the beam path 114 between the first positioner 106 and the scan lens 112. In embodiments where the scan lens 112 is coupled to one or more actuators of a third positioner 110 (e.g., one or more linear actuators capable of moving the scan 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 positioned and operable to move the first positioner 106 in a direction corresponding to the direction in which the scan lens 112 is moved by the third positioner 110. As can be understood, the actuator 150 is configured to move the first positioner 106 to maintain a constant (or at least substantially constant) optical path length between the first positioner 106 and the entrance pupil 132 of the scan lens 112 when the scan lens 112 moves (for example, as shown in Figure 6), in response to one or more commands output by the controller 122. Maintaining the optical path length ensures that the laser energy beam 116 has acceptable telecentricity when directed towards the workpiece 102. Figure 6 shows the scan lens 112 moving toward the fixed relay optical component 126, but the scan lens 112 moves toward the fixed relay optical component 126, and for this reason it can be understood that the actuator 150 may move the first positioner 106 toward the fixed relay optical component 126 to maintain a constant optical path length between the first positioner 106 and the entrance pupil 132.

[0051] During operation, the actuator 150 can move the first positioner 106 by a distance equal to or different from the distance the scan lens 112 moves. For example, in one embodiment, the fixed relay optical component 126 has a magnification M equal to (or at least substantially equal to) 1 such that the distance the first positioner 106 must move along the beam path so that it moves away from the fixed relay optical component 126 in order to reposition the pivot point 134 at the center of the entrance pupil 132 is equal to (or at least substantially equal to) the distance the pivot point 134 moves along the beam path. In an example of another embodiment, the fixed relay optical component 126 has a magnification M greater than 1 such that the distance the first positioner 106 must move along the beam path so that it moves away from the fixed relay optical component 126 in order to reposition the pivot point 134 at the center of the entrance pupil 132 is shorter than the distance the pivot point 134 moves along the beam path. For example, in one embodiment, the fixed relay optical component 126 may have a magnification M equal to (or at least substantially equal to) 2, so that when the scan lens 112 moves 100 mm along the beam path 114 toward the fixed relay optical component 126, the actuator 150 will move (i.e., 100 mm / M 2 The first positioner 106 only needs to be moved along the beam path 114 by a distance of 25 mm. It can be understood that the magnification of the fixed relay optical component 126 may be adjusted by any other desirable or advantageous method.

[0052] Figures 5 and 6 show a configuration in which the actuator 150 moves the first positioner 106 along a direction different from the direction in which the scan lens 112 can move. However, if, for example, one or more mirrors are placed in the beam path to properly relay the beam path 114 from the first positioner 106 to the scan lens 112, it can be understood that the actuator 150 may move the first positioner 106 in one direction or any other direction.

[0053] B. Embodiment 2: Movable Optical Relay System As described above, the optical relay system can position the image of the first positioner 106 on the entrance pupil 132 of the scan lens 112, thereby rotating the laser energy beam 116 propagating along the beam path 114 around a pivot point 134 located at or at least very close to the entrance pupil 132 of the scan lens 112. Movement of the scan lens 112 relative to the first positioner 106 (or second positioner 108) may cause the image of the first positioner 106 to be mispositioned away from the entrance pupil 132. In one embodiment, the optical relay system 200 may maintain the position of the pivot point 134 on the entrance pupil 132 by moving in sync with the movement of the scan lens 112, thereby ensuring that the laser energy beam 116 has acceptable telecentricity when directed towards the workpiece 102.

[0054] Figures 7A and 7B show two spatial states of an embodiment of a movable optical relay system, which includes an optical relay 200 positioned optically connected to a first positioner 106 and mounted on a component of a third positioner 110 (e.g., a linear stage 218 on which the optical relay 200 can move along the X-axis, as shown), and a number of mirrors (e.g., mirrors 214a, 214b, 216). The optical relay 200 is mounted on a carriage 210, which is movable by the linear stage 218 (e.g., in response to one or more commands output by a controller 122). Similarly, the mirrors 216, the second positioner 108, and the scan lens 112 are mounted on the carriage 210 of the linear stage 218 together with the optical relay 200. The linear stage 218 can be mounted on a frame or gantry-like structure 217 of the laser processing apparatus 100. In other embodiments, the optical relay 200 may be located on an auxiliary stage (not shown) instead of the stage 218. During use, the auxiliary stage may position the optical relay 200 in response to the motion given to the second positioner 108 and scan lens 112 by the linear stage 218. Mirrors 214a and 214b (e.g., folding mirrors) are provided on the structure 217. Thus, the linear stage 218 can move not only the optical relay 200 and mirrors 216 but also the second positioner 108 and scan lens 112 relative to the first positioner 106 and mirrors 214a and 214b. As shown, the mirrors 214a, 214b, and 216 are arranged to optically connect the optical relay 200 to the scan lens 112.

[0055] 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 provided in the optical input 206 and a second lens 202b provided in the optical output 208.

[0056] In the illustrated embodiment, the first reflective surface 204a and the second reflective surface 204b are parallel to each other (or at least substantially parallel). It will be understood that the first reflective surface 204a and the second reflective surface 204b do not have to be parallel to each other. Based on the above configuration, the laser energy beam 116 enters the optical input 206 through the first lens 202a, is incident on the first reflective surface 204a, and is reflected by the first reflective surface 204a toward the second reflective surface 204b. The laser energy beam 116 is reflected back and, after four reflections between the reflective surfaces 204a and 204b, exits the optical relay 200 through the optical output 208. The folding of the optical path between the reflective surfaces 204a and 204b makes it possible to make the optical relay 200 compact enough to be mounted on the carriage 210. The laser energy beam 116 passes through the second lens 202b and exits the optical output 208, then propagates toward the mirror 214a. The laser energy beam 116 is reflected from the mirror 214a toward the mirror 214b, and then reflected toward the mirror 216. The mirror 216 is positioned to reflect the laser energy beam 116 toward the scan lens 112 (for example, via the second positioner 108). In the illustrated embodiment, the second positioner 108 is provided as a two-axis galvanometer mirror system, and the entrance pupil 132 of the scan lens 112 is located between its X-axis galvanometer mirror component and its Y-axis galvanometer mirror component. Under certain operating conditions of the apparatus 100, the power of the laser energy beam 116 is high enough to damage the reflective surfaces 204a and 204b if it were directly focused upon them. To avoid this, in the illustrated embodiment, the first lens 202a is configured to focus the laser energy beam 116 to a point between the first reflective surface 204a and the second reflective surface 204b (for example, a nominal midpoint between the reflective surfaces 204a and 204b). This reduces the laser fluence on surfaces 204a and 204b to a degree sufficient to avoid damage to surfaces 204a and 204b.

[0057] Generally, the optical relay 200 may be configured to expand the laser energy beam 116 to compensate for changes in optical path length caused by folding the optical path two or more times (for example, depending on the configuration of the device 100) in order to maintain the position of the pivot point 134 at or near the scan lens entrance pupil 132.

[0058] In one embodiment, referring to Figure 7A, the optical input 206 is located at a distance X0 from the first positioner 106. As shown in Figure 7B, the optical input 206 is repositioned at a distance X1 from the first positioner 106, which has been moved by a distance D = X1 - X0 (for example, by the operation of the linear stage 218). Since the laser energy beam 116 is reflected twice by the mirrors 214a and 214b, when the optical relay 200 is moved in the +X direction, the distance between the optical output 208 and the scan lens 112 changes by a factor of 2. As a result, the image of the first positioner 106 moves away from the scan lens 112 by a distance of 2 × D, potentially moving the relayed pivot point 134 outside the entrance pupil 132. This introduces a telecentric error in the beam irradiating the workpiece 102. To address this, in this embodiment, lenses 202a and 202b can impart a lateral magnification of M=sqrt(2)=1.414 to the laser energy beam 116. As a result, the beam emitting from the optical output 208 has a width 1.414 times that of the beam entering the optical input 206. The resulting vertical magnification is M 2 = 2, and as a result, the relayed pivot point 134 moves by a distance of 2 × D, thereby maintaining not only the beam size of the laser energy beam 116 in the entrance pupil 132 but also the position of the relayed pivot point 134 when the scan lens 112 and optical relay 200 are moved by the linear stage 218.

[0059] In another embodiment, the optical path may be folded three times, such as when the optical input 206 is repositioned at a distance X1 from the first positioner 106, which has been moved by a distance D=X1-X0 (for example, by the operation of the linear stage 218). Since the laser energy beam 116 is folded three times, when the optical relay 200 is moved in the +X direction, the distance between the optical output 208 and the scan lens 112 changes by a factor of 3. As a result, the image of the first positioner 106 moves away from the scan lens 112 by a distance of 3×D. To accommodate this, in this embodiment, lenses 202a and 202b may impart a transverse magnification of M=sqrt(3)=1.732 to the laser energy beam 116. As a result, the beam leaving the optical output 208 has a width 1.732 times the width of the beam entering the optical input 206. The resulting vertical magnification is M 2 = 3, and as a result, the relayed pivot point 134 moves by a distance of 3 × D, thereby maintaining not only the beam size of the laser energy beam 116 in the entrance pupil 132 but also the position of the relayed pivot point 134 when the scan lens 112 and optical relay 200 are moved by the linear stage 218. In other possible configurations of the device 100, the optical path between the relays 200 may be folded back more than three times, and it can be understood that the lenses 202a and 202b may be configured to compensate for this and give the laser energy beam 116 an appropriate magnification in order to maintain the pivot point 134 in or near the entrance pupil 132.

[0060] In Figures 7A and 7B, the second positioner 108 is shown overlapping with the entrance pupil 132, but it can be understood that the second positioner 108 may be positioned so as not to overlap with the entrance pupil 132. For example, the mirror 216 shown in Figures 7A and 7B may be replaced with the second positioner 108.

[0061] C. Embodiment 3: Light delay line with retroreflector Figures 8 and 9 show the positional states of an optical relay system provided as an optical delay line incorporating a retroreflector, such as optical delay line 300. The optical delay line 300 receives the laser energy beam 116 from the first positioner 106 and relays it to the scan lens 112 via the folding mirror 130. It should be understood that the folding mirror 130 is optional and can be omitted if the direction of one or more other components of the laser processing apparatus 100 (e.g., the first positioner 106, the second positioner 108, the scan lens 112, the optical delay line 300, or any combination thereof) is modified to ensure that the laser energy beam 116 propagates reliably from the first positioner 106 to the scan lens 112. In this way, the laser energy beam 116 is directed to the entrance pupil 132 of the scan lens 112 or to a relay point 134 in its vicinity.

[0062] Generally, the optical delay line 300 includes a motion system 308 (e.g., a linear stage), a retroreflector 310, a relay reflector 320, and a delay line body 302. The motion system 308, the retroreflector 310, and the relay reflector 320 are mounted on the delay line body 302, and the retroreflector 310 is movable relative to the relay reflector 320 by the motion system 308. In one embodiment, the optical delay line 300 is installed in the laser processing apparatus 100 so as to be fixed in position relative to a first positioner 106, and the scan lens 112 is movable relative to the optical delay line 300. In other embodiments, the optical delay line 300 is movable relative to the first positioner 106 and can be fixed in position relative to the scan lens 112. For example, the optical delay line 300 may be connected to one or more actuators of the third positioner 110 (for example, one or more linear actuators capable of moving the scan lens 112 along any of the X, Y, and / or Z directions). In other embodiments, the optical delay line 300 is movable relative to the first positioner 106 and the scan lens 112.

[0063] In the illustrated embodiment, the retroreflector 310 is a corner reflector (known as a “corner cube”) including a first reflective surface 314, a second reflective surface 316, and a third reflective surface 318 oriented substantially orthogonally to each other. In other embodiments, the retroreflector 310 may not have the third reflective surface 318. In other embodiments, the retroreflector 310 may be provided as a pair of mirrors or as a spherical retroreflector. Those skilled in the art will understand that various retroreflectors can be used within the optical delay line 300. In the illustrated embodiment, when the retroreflector 310 comprises three reflective surfaces 314, 316, and 318, the beams propagating to and from the retroreflector 310 remain parallel regardless of the direction of the beams relative to the reflective surfaces of the retroreflector 310.

[0064] The relay reflector 320 is configured to reflect the laser energy beam 116 to the retroreflector 310 and the laser energy beam returning from the retroreflector 310 to the scan lens 112. In the illustrated embodiment, the relay reflector 320 includes a first reflective surface 324 and a second reflective surface 326 attached to or formed on the relay reflector body 322. In the illustrated embodiment, the first reflective surface 324 and the second reflective surface 326 are oriented orthogonal to each other. In other embodiments, the first reflective surface 324 and the second reflective surface 326 do not need to be oriented orthogonal to each other. In other embodiments, the relay reflector 320 may be provided as two mirrors provided on the relay reflector body 322. It will be understood that various optical components or optical surfaces may be attached to or formed on the relay reflector body 322.

[0065] In embodiments where the scan lens 112 is movable relative to the optical delay line 300 (for example, the optical delay line 300 is installed in the laser processing apparatus 100 so as to be fixed in position relative to the first positioner 106) when the scan lens 112 is moved relative to the first positioner 106 (for example, in the +X direction), the retroreflector 310 is moved relative to the relay reflector 320 (for example, in the -Z direction). Thus, the optical path length between the scan lens 112 and the first positioner 106 is maintained such that the pivot point 134 of the laser energy beam 116 remains located at or near the entrance pupil 132 of the scan lens 112 when the scan lens 112 is moved. For example, referring to Figures 8 and 9, during use, the scan 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 optical delay line 300 (as shown in Figure 9). The change is ΔX = X1 - X0. Synchronized with the movement of the scan lens 112, the retroreflector 310 moves in the -Z direction from a distance Z0 relative to the relay reflector 320 (as shown in Figure 8) to a distance Z1 relative to the relay reflector 320 (as shown in Figure 9). The change in position is ΔZ = Z0 - Z1. In this embodiment, ΔX ≈ 2ΔZ. Since the optical path is folded twice in the Z direction by the optical delay line 300, the original optical path length from the first positioner 106 to the scan lens 112 is maintained when ΔX ≈ 2ΔZ.

[0066] In embodiments where the optical delay line 300 is movable relative to the first positioner 106 (e.g., by the scan lens 112) or is movable relative to the scan lens 112 itself, when the optical delay line 300 is moved relative to the first positioner 106 (or the scan lens 112) (e.g., in the +X direction), the retroreflector 310 can be moved relative to the relay reflector 320 (e.g., in the -Z direction). Thus, the optical path length between the scan lens 112 and the first positioner 106 is maintained such that the pivot point 134 of the laser energy beam 116 remains located at or near the entrance pupil 132 of the scan lens 112 when the scan lens 112 is moved. For example, referring to Figures 8 and 9, during use, the optical delay line 300 moves in the +X direction from a distance X2 relative to the first positioner 106 to a distance X3 relative to the first positioner 106. The change is ΔX = X3 - X2. Synchronized with the movement of the optical delay line 300 in the +X direction, the retroreflector 310 moves in the -Z direction from a distance Z0 relative to the relay reflector 320 (as shown in Figure 8) to a distance Z1 relative to the relay reflector 320 (as shown in Figure 9). The change in position is ΔZ = Z0 - Z1. In this embodiment, ΔX ≈ 2ΔZ. Since the optical path is folded twice in the Z direction by the optical delay line 300, the original optical path length from the first positioner 106 to the scan lens 112 is maintained when ΔX ≈ 2ΔZ.

[0067] The optical delay line 300 may be configured to fold the optical path between the first positioner 106 and the scan lens 112 any number of times, and it can be seen that this can 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. As a result, the optical path length is maintained at a ratio of ΔX = 4ΔZ. Furthermore, any number of optical relay lines or subsystems may be provided to maintain the optical path length in any desired or beneficial way.

[0068] In Figures 8 and 9, the second positioner 108 is shown overlapping the entrance pupil 132 (for example, as described above with respect to Figures 7A and 7B), but it can be understood that the second positioner 108 may be positioned so as not to overlap the entrance pupil 132. For example, the folding mirror 130 may be replaced by the second positioner 108. During operation, the second positioner 108 and the scan lens 112 may be scanned along the X direction in the same manner as in the embodiments described above, and the optical path length can be maintained by synchronously moving the retroreflector 310 relative to the relay reflector 320.

[0069] In describing this embodiment, it should be understood that the X, Y, or Z directions may be used arbitrarily. For example, the optical delay line 300 may be oriented such that the change in position between the retroreflector 310 and the relay reflector 320 is also in the X direction. The absolute value of the change in distance between the retroreflector 310 and the relay reflector 320 (and correspondingly the absolute value of the change in distance between the optical delay line 300 and the scan lens 112) results in maintaining the optical path length. This also applies to the embodiments described below.

[0070] D. Embodiment 4: Optical delay line with polarizing beam splitter Figures 10 and 11 show the positional states of an optical relay system provided as an optical delay line incorporating a polarization beam splitter, such as the optical delay line 400. The optical delay line 400 receives the laser energy beam 116 from the first positioner 106 and relays it to the scan lens 112 via the folding mirror 130. In this embodiment, the laser energy beam 116 initially sent to the optical delay line 400 is linearly polarized. It should be understood that the folding mirror 130 is optional and can be omitted if the orientation of one or more other components of the laser processing apparatus 100 (e.g., the first positioner 106, the second positioner 108, the scan lens 112, the optical delay line 400, or any combination thereof) is corrected to ensure that the laser energy beam 116 propagates reliably from the first positioner 106 to the scan lens 112. In this way, the laser energy beam 116 is directed towards the entrance pupil 132 of the scan lens 112 or the pivot point 134 that is relayed therein.

[0071] Generally, the optical delay line 400 includes a polarizing beam splitter 430, a retarder 412, a reflector 410, a motion system 408 (e.g., a linear stage), and a delay line body 402. The polarizing beam splitter 430, the retarder 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 the motion system 408. The optical delay line 400 may be installed in the laser processing apparatus 100 so as to be fixed in position relative to the first positioner 106 and the scan lens 112, or it may be movable relative to the first positioner 106 and / or the scan lens 112 (for example, as described above with respect to the optical delay line 300).

[0072] The retarder 412 is positioned between the polarizing beam splitter 430 and the reflector 410 and is configured to change the polarization of the laser energy beam passing through the retarder 412 (for example, from linear polarization to circular polarization, or vice versa). The reflector 410 is positioned and configured to reflect the incident laser energy beam 116 and direct it toward the polarizing beam splitter 430. Therefore, the polarization of the laser energy beam 116 propagating from the polarizing beam splitter 430 is converted from linear polarization to circular polarization by the retarder 412, and the polarization of the laser energy beam 116 propagating from the reflector 410 is converted from circular polarization to linear polarization by the retarder 412. However, in this case, the polarization of the laser energy beam 116 reflected back (from the retarder 412) to the polarizing beam splitter 430 is rotated by 90 degrees with respect to the polarization direction of the laser energy beam 116 propagating from the polarizing beam splitter 430 (to the retarder 412). Therefore, the laser energy beam 116 that is reflected back to the polarizing beam splitter 430 is reflected by the polarizing beam splitter 430 (for example, via the folding mirror 130) toward the scanning lens 112.

[0073] The reflector 410 is mounted on a motion system 408 attached to the delay line body 402. The delay line body 402 is configured to change the position of the reflector 410 relative to the polarizing beam splitter 430. If necessary, the polarizing beam splitter 430 may be mounted on the motion system 408 so that the position of the polarizing beam splitter 430 is changed relative to the reflector 410.

[0074] In an embodiment where the scan lens 112 is movable relative to the optical delay line 400 (the optical delay line 300 is installed in the laser processing apparatus 100 so as to be fixed in position relative to the first positioner 106), when the scan lens 112 is moved relative to the first positioner 106 (for example in the +X direction), the reflector 410 is moved relative to the polarizing beam splitter 430 (for example in the +Z direction). Thus, the optical path length between the scan lens 112 and the first positioner 106 is maintained such that the pivot point 134 of the laser energy beam 116 remains located at or near the entrance pupil 132 of the scan lens 112 when the scan lens 112 is moved. For example, referring to Figures 10 and 11, the scan 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 optical delay line 400 (as shown in Figure 11). The change is ΔX = X1 - X0. Synchronized with the movement of the scan lens 112, the reflector 410 moves in the +Z direction from a distance Z0 relative to the polarizing beam splitter 430 (as shown in Figure 10) to a distance Z1 relative to the polarizing beam splitter 430 (as shown in Figure 11). The change in position is ΔZ = Z0 - Z1. In this embodiment, ΔX ≈ 2ΔZ. Since the optical path is folded twice in the Z direction by the optical delay line 400, the original optical path length from the first positioner 106 to the scan lens 112 is maintained when ΔX ≈ 2ΔZ.

[0075] It can be understood that the optical delay line 400 may be configured to fold the optical path between the first positioner 106 and the scan lens 112 any number of times (for example, to provide an arbitrary 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 twice. As a result, the optical path length is maintained at a ratio of ΔX = 4ΔZ. Any number of optical relay systems or subsystems may be provided to maintain the optical path length in any desired or beneficial way.

[0076] In the embodiments described above, the reflector 410 is provided as a zero-phase-shift reflector. However, in other embodiments, the reflector 410 may be provided as a reflection phase retarder, such as a half-wavelength reflection phase retarder, configured to rotate the polarization direction of the laser energy beam 116 as it reflects the laser energy beam 116 back toward the polarization beam splitter 430. In this case, the retarder 412 is not required. The use of a half-wavelength reflection phase retarder may be preferable when the laser energy beam is in the UV, mid-infrared, or long-infrared wavelength range of the electromagnetic spectrum.

[0077] In Figures 10 and 11, the second positioner 108 is shown overlapping the entrance pupil 132 (for example, as described above with respect to Figures 7A and 7B), but it can be understood that the second positioner 108 may be positioned so as not to overlap the entrance pupil 132. For example, the folding mirror 130 may be replaced by the second positioner 108. During operation, the second positioner 108 and the scan lens 112 may be scanned in the X direction in the same manner as in the embodiments described above, and the optical path length can be maintained by synchronously moving the reflector 410 relative to the polarizing beam splitter 430.

[0078] E. Embodiment 5: Zoom Optical Relay System As described above, one embodiment of the optical relay system may have a fixed magnification capable of achieving a target spot size on the surface of the workpiece, while ensuring that the laser energy beam 116 propagating along the beam path 114 rotates about a pivot point 134 located at or very close to the entrance pupil 132 of the scan lens 112. However, according to other embodiments, an optical relay system may be provided that relays the beam pivot point 134 to the entrance pupil 132 of the scan lens 112 and can change the magnification of the laser energy beam (for example, to adjust or maintain the laser spot size on the workpiece 102). Below, exemplary embodiments of an optical relay system that can vary the magnification, output a collimated beam, and keep the position of the pivot point constant are described. Such an optical relay system may be located optically downstream of one or more positioners in the system (for example, after the first positioner 106 or the second positioner 108).

[0079] Figure 12 shows an example embodiment of an optical relay system 500 configured to relay the image (or focal plane) of a first positioner 106 (or second positioner 108) to the entrance pupil 132 of a scan lens 112. In this embodiment, the position of the optical relay system 500 is fixed relative to the first positioner 106 (or second positioner 108) and the scan lens 112. If necessary, the position of the optical relay system 500 (or its components) may be adjustable relative to the first positioner 106, the second positioner 108 and / or the scan lens 112, as described below.

[0080] As shown in the illustration, the relay system 500 may include a first lens 502, a zoom lens assembly 510, and a second lens 506. An aperture 504 capable of restricting the light incident on the zoom lens assembly 510 may be located between the first lens 502 and the zoom lens assembly 510 (for example, to allow separation of diffraction orders, or to limit the angular range of the laser energy beam 116 (and its peripheral rays 116') diffracted by the first positioner 106 or the laser energy beam 116 reflected by the second positioner 108). In the illustrated embodiment, the zoom lens assembly 510 is located between the first lens 502 and the second lens 506. Although lenses 502 and 506 are shown as biconvex lenses in Figure 12, various positive lenses (for example, a planar convex positive meniscus lens, a positive achromatic lens, an aspherical lens, or lenses arranged to form a double or triple lens, or any combination thereof) may be used depending on the operating conditions of the device 100.

[0081] In this embodiment, the zoom lens assembly 510 includes a first lens group 516 and a second lens group 522. The first lens group 516 is spaced a fixed distance C from the second lens group 522. 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. In the embodiment shown in Figure 12, the first lens group 516 and the second lens group 522 may be provided as a telephoto double lens symmetrically arranged with respect to the transverse centerline 530 of the zoom lens assembly 510. In this embodiment, 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 spaced a distance A apart. In the second lens group, lens 518 is a biconvex lens and lens 520 is a plano-concave lens, and lenses 518 and 520 are spaced apart by a distance B and arranged mirror-symmetrically with respect to the plano-concave lens 512 and biconvex lens 514 of the first lens group 516. Distance A can be adjusted by any preferred 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 preferred or desired method known in the art (also referred to herein as "adjustment of the second lens group 522").

[0082] The position of the zoom lens assembly 510 within the optical relay system 500 can be set or adjusted to adjust the magnification (also referred to herein as the “magnification setting point”) of the optical relay system 500 in order to set or adjust the laser spot size of the laser energy beam 116. The position of the zoom lens assembly 510 can be set manually (for example, by the manufacturer of the apparatus 100, by a user or other operator of the apparatus 100, by an application engineer or technician responsible for developing a process or recipe for processing the workpiece 102, or any combination thereof) and then fixed in the appropriate position. In other embodiments, the zoom lens assembly 510 may be mounted on a first positioner 524 (e.g., a linear stage, voice coil, optical mount, etc.) that can change the position of the zoom lens assembly 510 within the optical relay system 500 (for example, in response to one or more commands from a controller 122).

[0083] 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 placing the first lens group 516 and the second lens group 522 on the second positioner 526 and the third positioner 528, respectively. In this embodiment, when the magnification setting point of the optical relay system 500 is set, adjustment of the first lens group 516 and the second lens group 522 may be necessary to achieve collimation of the laser energy beam 116 between the first lens group 516 and the second lens group 522, thereby generating a pivot point between the lens groups 516 and 522. Furthermore, adjustment of the first lens group 516 and the second lens group 522 may be necessary to achieve collimation of the laser energy beam 116 behind the second lens 506 in order to position the pivot point 134 in the scan lens entrance pupil 132. Furthermore, the first lens group 516 and the second lens group 522 can 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 scan lens. The adjustment of the first lens group 516 and the second lens group 522 can be performed in synchronization with, or subsequently (in any order) with, the adjustment of the position of the zoom lens assembly 510 within the optical relay system 500, or by an iterative process.

[0084] Depending on the optical performance requirements of the device 100, other embodiments of the zoom lens assembly 510 may be used. For example, in one other embodiment, the distance C between the first lens group 516 and the second lens group 522 may be adjustable rather than fixed. In other embodiments, the first lens group 516 and the second lens group 522 may include various combinations of positive lenses (e.g., planar convex positive meniscus lenses, positive achromatic lenses, aspherical lenses, etc., arranged to form a double or triple lens, or any combination thereof) and negative lenses (e.g., biconcave, plano-concave, negative meniscus lenses, negative achromatic lenses, etc., arranged to form a double or triple lens, or any combination thereof) in any order or at any interval.

[0085] As described above, when the magnification setting point of the optical relay system 500 is adjusted (for example, to adjust or maintain the laser spot size on the workpiece 102), adjustment of the first lens group 516 and the second lens group 522 may be necessary. Figures 13A to 13C show various positional states of the optical relay system 500, illustrating an example of the effect of changes in the position of the magnification setting point and the pivot point 134 on the laser spot size, and how the position of the pivot point 134 can be adjusted by adjusting the first lens group 516 and the second lens group 522.

[0086] Figure 13A shows an optical relay system 500 positioned between the first positioner 106 (or second positioner 108) and the scan lens 112 such that when the laser energy beam 116 is scanned (for example, by diffraction by the first positioner 106 or by reflection by the second positioner 108), the pivot point 134 is located at or near the entrance pupil 132 of the scan lens 112. As shown, the optical relay system 500 includes a zoom lens assembly 510 positioned between the first lens 502 and the second lens 506. The lenses of the first lens group 516 are spaced apart by a distance A, and the lenses of the second lens group 522 are spaced apart by a distance B. In this embodiment, the distance C between the first lens group 516 and the second lens group 522 is fixed. Below the first positioner 106 (e.g., the image plane of the first positioner 106), a laser spot 532 having a diameter D0 is shown. Below the entrance pupil 132, a laser spot 532' having a diameter D1 (e.g., amplified by the optical relay system 500) is shown. In this positional state, the magnification setting point of the optical relay system 500 is set so that the laser spot 532 is laterally magnified from a diameter D0 (e.g., 30 μm) to a diameter D1 = 1.414 × D0 = 42 μm by a factor M (e.g., 1.414).

[0087] Figure 13B shows an example of the change in the positional state shown in Figure 13A when the magnification setpoint of the optical relay system 500 is adjusted by moving the zoom lens assembly 510 toward the first lens 502 (for example, by the operation of the first positioner 524 shown in Figure 12). In this example, the magnification setpoint M changes from 1.414 to 1.50, resulting in a lateral expansion of the diameter D0 (e.g., 30 μm) of the laser spot 532 to D2 = 1.50 × D0 = 45 μm. This change in the magnification setpoint changes the vertical magnification of the image plane of the first positioner 106, causing a mispositioning of the pivot point 134 from the entrance pupil 132.

[0088] Figure 13C shows an example of a change in the positional state of the optical relay system 500 shown in Figure 13B. The spacing A of the first lens group 516 is adjusted to spacing A' (for example, by activating the second positioner 526 shown in Figure 12), and the spacing B of the second lens group 522 is adjusted to spacing B' (for example, by activating the third positioner 528 shown in Figure 12). These adjustments change the vertical magnification for repositioning the pivot point 134 to the entrance pupil 132, while maintaining the lateral magnification of the laser spot 532" at 45 μm.

[0089] III. Conclusion The foregoing describes embodiments and examples of the present invention and should not be construed as limiting thereto. While several specific embodiments and examples have been described with reference to the drawings, those skilled in the art will readily recognize that many improvements are possible to the disclosed embodiments and examples and other embodiments without departing largely from the novel teachings and advantages of the present invention. Therefore, all such improvements are intended to fall within the scope of the present invention as defined in the claims. For example, those skilled in the art will understand that the subject matter of any sentence or paragraph, example or embodiment can be combined with the subject matter of some or all of the other sentences or paragraphs, examples or embodiments, unless such combinations are mutually exclusive. Therefore, the scope of the present invention should be determined by the following claims and their equivalents.

Claims

1. A first positioner configured to deflect the laser energy beam around a pivot point, A scanning lens for focusing the laser energy beam onto a workpiece, comprising a scanning lens movable relative to the first positioner, An optical relay system configured to move in sync with the movement of the scan lens and maintain the position of the pivot point at the entrance pupil of the scan lens. A system equipped with these features.

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

3. The system according to claim 1 or 2, wherein the scanning lens is movable relative to the optical relay system.

4. The optical relay system is movable relative to at least one selected from the scan lens and the first positioner, according to any one of claims 1 to 3.

5. The aforementioned optical relay system is, Optical input and A first reflector having a first reflective surface, the first reflector being positioned to receive the laser energy beam propagating from the first positioner, Light output and, A second reflector having a second reflective surface opposite to the first reflective surface, Includes, The first reflective surface and the second reflective surface are arranged and configured to relay the laser energy beam received from the optical input by the first reflector to the optical output. The system according to any one of claims 1 to 4.

6. The aforementioned optical relay system is, A first lens is arranged and configured to focus the laser energy beam within the optical relay system, A second lens is positioned and configured to focus the laser energy beam exiting the optical relay system. It further includes, The first lens and the second lens are configured to magnify the laser energy beam. The system according to claim 5.

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

8. The system according to claim 5, further comprising a stage connected to the optical relay system, the stage capable of changing the position of the optical relay system with respect to at least one selected from the scan lens and the first positioner.

9. The system according to any one of claims 1 to 8, further comprising a second positioner disposed between the optical relay system and the scan lens.

10. The system according to claim 9, wherein the second positioner is at least one selected from the group consisting of a galvanometer, an AOD system, a fast steering mirror, and a rotating polyhedron mirror.

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