Orthocircularly polarized light generating device, laser processing equipment and laser processing method

Abstract

The invention provides a perfect circularly polarized light generation device, laser processing equipment and a laser processing method, and the device comprises an elliptically polarized light generation system which is used for generating elliptically polarized light; the polarization modulation system is arranged on the light emitting side of the elliptically polarized light generation system, and the polarization modulation system is configured to apply periodically-changed deflection modulation to the azimuth angle of the elliptically polarized light so as to output the elliptically polarized light with the periodically-changed azimuth angle, and the integral average effect of the projection of the elliptically polarized light with the periodically-changed azimuth angle along the light beam emergent direction on time is equivalent to that of perfect circularly polarized light. According to the embodiment of the invention, periodically changing deflection modulation is applied to the azimuth angle of the elliptically polarized light through the polarization modulation system, and the perfect circularly polarized light can be generated.

Description

Technical Field

[0001] This application belongs to the field of optical technology, and more specifically, relates to a circularly polarized light generation device, laser processing equipment, and laser processing method. Background Technology

[0002] Circularly polarized light is widely used in laser processing (such as cutting, drilling, and micro / nano fabrication) and many optical experiments due to its unique properties of interacting with matter. Currently, the most common method for generating circularly polarized light is to convert linearly polarized light emitted from the laser emitter into circularly polarized light using a quarter-wave plate.

[0003] However, due to factors such as material defects, processing errors, wavelength matching, and installation deviations, even when using the highest quality 1 / 4 waveplate, the emitted light is not ideal circularly polarized light (right circularly polarized light), but rather elliptically polarized light (also known as quasi-circularly polarized light). Elliptically polarized light reduces the precision of laser processing and affects the laser process effect.

[0004] Therefore, there is an urgent need to provide a method that can generate circularly polarized light. Summary of the Invention

[0005] The purpose of this application is to provide a circularly polarized light generating device, laser processing equipment, and laser processing method to solve the technical problem of difficulty in generating circularly polarized light.

[0006] In a first aspect, embodiments of this application provide a circularly polarized light generating device, used for laser processing of a target object, including:

[0007] Elliptically polarized light generation system, used to generate elliptically polarized light; A polarization modulation system is disposed on the light-emitting side of the elliptically polarized light generation system. The polarization modulation system is configured to apply periodically varying deflection modulation to the azimuth angle of the elliptically polarized light to output elliptically polarized light with periodically varying azimuth angle. The integral averaging effect of the projection of the periodically varying azimuth angle elliptically polarized light along the beam emission direction in time is equivalent to that of circularly polarized light.

[0008] In one possible implementation of the first aspect: the polarization modulation system includes a rotation module and a second polarization conversion module, the second polarization conversion module being used to transmit the elliptically polarized light, the second polarization conversion module being disposed on the rotation module, the rotation module being configured to drive the second polarization conversion module to rotate around the optical axis of the elliptically polarized light at a target rotational speed, so as to output the elliptically polarized light with periodically changing azimuth angle, wherein the target rotational speed is N revolutions per second, and the duration of a single action of the circularly polarized light on the target processing object at a single processing point is T, N 2T is an integer.

[0009] In one possible implementation of the first aspect: the elliptically polarized light generation system comprises: The laser emitter is used to generate linearly polarized light; The first polarization conversion module is disposed on the light-emitting side of the laser emitting unit and is used to convert the linearly polarized light into the elliptically polarized light.

[0010] In one possible implementation of the first aspect: the first polarization conversion module is a quarter-wave plate, and the second polarization conversion module is a half-wave plate.

[0011] In one possible implementation of the first aspect, a collimating beam expander is further included, which is disposed on the light-emitting side of the laser emitting unit, and the linearly polarized light is injected into the first polarization conversion module after passing through the collimating beam expander.

[0012] Secondly, embodiments of this application also provide a laser processing apparatus, comprising: The circularly polarized light generating device described in the first aspect above is used to generate circularly polarized light; A worktable is located on the light-emitting side of the circularly polarized light generating device, and the circularly polarized light is used to process the target object on the worktable.

[0013] In one possible implementation of the second aspect: the laser processing equipment further includes a controller configured to: determine a target rotation speed according to the processing parameters corresponding to the target processing object, and control the rotation module of the circularly polarized light generating device according to the target rotation speed, so as to drive the second polarization conversion module of the circularly polarized light generating device to rotate around the optical axis of the elliptical polarized light at the target rotation speed.

[0014] Thirdly, embodiments of this application also provide a laser processing method applied to the laser processing equipment described in the first aspect above, the laser processing method comprising: Obtain the processing parameters of the target object, the processing parameters including the duration of a single action of the circular polarized light on a single processing point of the target object; Place the target object to be processed on the worktable; The circularly polarized light generating device is controlled to generate circularly polarized light according to the processing parameters, and the circularly polarized light is used to perform laser processing on the target object on the worktable.

[0015] In one possible implementation of the third aspect: controlling the circularly polarized light generating device to generate circularly polarized light according to the processing parameters includes: The laser processing equipment is controlled to generate elliptically polarized light through an elliptically polarized light generation system. According to the processing parameters, the polarization modulation system of the laser processing equipment is controlled to apply periodically changing deflection modulation to the azimuth angle of the elliptically polarized light, so as to output elliptically polarized light with periodically changing azimuth angle. The integral averaging effect of the projection of the periodically changing elliptically polarized light along the beam exit direction over time is equivalent to that of circularly polarized light.

[0016] In one possible implementation of the third aspect: the step of controlling the polarization modulation system of the laser processing equipment to apply periodically varying deflection modulation to the azimuth angle of the elliptically polarized light according to the processing parameters, so as to output elliptically polarized light with periodically varying azimuth angles, includes: The target rotational speed of the second polarization conversion module of the polarization modulation system is determined based on the duration of the single action. The rotation module of the polarization modulation system is controlled to drive the second polarization conversion module to rotate around the optical axis of the elliptically polarized light at the target rotation speed, so as to output the elliptically polarized light with periodically changing azimuth angle.

[0017] In one possible implementation of the third aspect: the laser processing method is used to perform laser drilling on the target object, the depth of the laser-drilled hole being greater than or equal to 500 micrometers.

[0018] The beneficial effects of the circularly polarized light generating device, laser processing equipment, and laser processing method provided in this application are as follows: The circularly polarized light generating device includes an elliptically polarized light generating system and a polarization modulation system. The polarization modulation system is located on the light-emitting side of the elliptically polarized light generating system. After the elliptically polarized light generating system generates elliptically polarized light, the elliptically polarized light enters the polarization modulation system. The polarization modulation system applies periodically changing deflection modulation to the azimuth angle of the elliptically polarized light to output elliptically polarized light with periodically changing azimuth angle. The superposition and accumulation of the projection of the periodically changing elliptically polarized light along the beam emission direction in time achieves the effect of integral averaging at each azimuth angle of the elliptically polarized light, which is equivalent to outputting circularly polarized light. Therefore, by applying periodically changing deflection modulation to the azimuth angle of the elliptically polarized light through the polarization modulation system, circularly polarized light can be generated. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 A schematic diagram of a circularly polarized light generating device provided in an embodiment of this application. Figure 1 ; Figure 2 A schematic diagram of the propagation of polarized light in a circularly polarized light generating device provided in an embodiment of this application; Figure 3 A schematic flowchart of a laser processing method provided in an embodiment of this application; Figure 4 This is a schematic diagram of laser beam propagation provided in an embodiment of this application; Figure 5 This is a schematic diagram of laser drilling provided in an embodiment of this application; Figure 6 This is a schematic flowchart of a laser processing method provided for another embodiment of this application.

[0021] The following are the labeling elements in the figure: 100 - Elliptically polarized light generation system; 110 - Laser emitting component; 120 - First polarization conversion module; 200 - Polarization modulation system; 210 - Rotation module; 220 - Second polarization conversion module; 300 - Target processing object; 310 - Aperture structure; a - Linearly polarized light; b - Elliptically polarized light; c - Circularly polarized light. Detailed Implementation

[0022] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0023] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0024] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0025] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0026] Circularly polarized light is widely used in laser processing (such as cutting, drilling, and micro / nano fabrication) and many optical experiments due to its unique properties of interacting with matter. Currently, the most common method for generating circularly polarized light is to convert linearly polarized light emitted from the laser emitter into circularly polarized light using a quarter-wave plate. This requires that the vibration direction of the linearly polarized light incident on the quarter-wave plate be precisely at a 45° angle to the fast (or slow) axis of the quarter-wave plate, and that the quarter-wave plate ensures a precise 90° (π / 2) phase difference between the two components on the fast and slow axes to produce ideally circularly polarized light (perfectly circularly polarized light). However, even with the highest quality quarter-wave plates, it is difficult to meet these requirements. Therefore, the polarized light emitted from a quarter-wave plate is not ideally circularly polarized light, but rather elliptically polarized light (quasi-perfectly circularly polarized light).

[0027] When elliptically polarized light is used in laser processing, it can lead to a decrease in processing precision, thus affecting the processing effect. For example, in the process of laser processing micro-holes with high aspect ratios, when elliptically polarized light is incident on the hole wall, it is decomposed into P-beams parallel to the incident plane and S-beams perpendicular to the incident plane. Due to the difference in reflectivity of the P-beams and S-beams on the hole wall material, anisotropic reflection occurs when the P-beams and S-beams are reflected from the hole wall. This anisotropic reflection results in uneven distribution of laser energy at the bottom of the micro-hole, causing inconsistent melting and vaporization at different locations on the hole wall, ultimately leading to deformation of the bottom hole and a deviation of the center of the bottom hole from the propagation direction of the laser beam. When elliptically polarized light is used in optical experiments, it can cause distortion of the detection signal, thus affecting the reliability of the detection.

[0028] Even under ideal conditions, using the highest-grade quarter-wave plate to convert linearly polarized light into circularly polarized light, the resulting circularly polarized light is difficult to approximate a perfect circle. Furthermore, in practical applications, assembly errors and other factors further contribute to the even greater discrepancy between the actual generated elliptically polarized light and a perfect circle. Therefore, it is difficult to generate perfectly circularly polarized light in related technologies.

[0029] It is understood that the aforementioned elliptically polarized light refers to polarized light whose ratio of the minor axis to the major axis of the projected cross-section is less than 0.99, including quasi-circularly polarized light; circularly polarized light refers to polarized light whose ratio of the minor axis to the major axis of the projected cross-section is greater than or equal to 0.99, for example, the ratio of the minor axis to the major axis of the projected cross-section is 0.995, 0.999, 0.9995, 0.9999, 1, etc.

[0030] Please refer to the following: Figure 1 and Figure 2 The circularly polarized light generating apparatus provided in the embodiments of this application will now be described. The circularly polarized light generating apparatus includes an elliptically polarized light generating system 100 and a polarization modulation system 200. The elliptically polarized light generating system 100 is used to generate elliptically polarized light. The polarization modulation system 200 is disposed on the light-emitting side of the elliptically polarized light generating system 100. After the elliptically polarized light b generated by the elliptically polarized light generating system 100 passes through the polarization modulation system 200, the ratio of the minor axis to the major axis of the projected cross-section of the output polarized light is very large (e.g., greater than 0.99), which is equivalent to circularly polarized light c.

[0031] For example, the polarization modulation system 200 is configured to apply periodically varying deflection modulation to the azimuth angle of elliptically polarized light b to output elliptically polarized light b with a periodically varying azimuth angle, wherein the integral-averaged effect of the projection of the periodically varying elliptically polarized light b along the beam exit direction over time is equivalent to that of circularly polarized light c. It is understood that the ratio of the minor axis to the major axis of the projected cross-section of the circularly polarized light is greater than or equal to 99%, and the azimuth angle φ refers to the angle between the major axis of the ellipse and the X-axis; optionally, 0 ≤ φ < π.

[0032] The polarization modulation system 200 applies periodically varying deflection modulation to the azimuth angle of the elliptically polarized light b, causing the elliptically polarized light b to be rapidly rotated (e.g., its major axis is rapidly deflected to different positions). The projection of the periodically varying azimuth angle elliptically polarized light b along the beam exit direction accumulates in the effective region, filling different positions. The accumulated elliptically polarized light b over time superimposes to form circularly polarized light c. In other words, all the elliptically polarized light b within a certain time period in the effective region achieves an integral averaging effect, resulting in the superposition of elliptically polarized light b at different times in the effective region to form circularly polarized light c.

[0033] In one application scenario, a circularly polarized light generating device is used to process aperture structures, specifically based on circularly polarized light c. In this scenario, during aperture structure processing, the polarization modulation system 200 applies periodically varying deflection modulation to the azimuth angle of the elliptically polarized light b. The elliptically polarized light b acting on the aperture structure is superimposed on the entire circumference of the aperture structure; therefore, the integral-average effect of the elliptically polarized light b acting on the aperture structure is equivalent to that of the circularly polarized light c.

[0034] In another application scenario, the circularly polarized light generator is used for optical experiments, specifically for optical testing based on circularly polarized light c. For example, the circularly polarized light c generated by the generator is incident on a polarization light detector, which analyzes the c. In this application scenario, the polarization modulation system 200 applies periodically varying deflection modulation to the azimuth angle of the elliptically polarized light b within the response time of the polarization light detector. Within one response time, the polarization light detector senses all the elliptically polarized light b accumulated over a period of time. The integral average effect of all the elliptically polarized light b is equivalent to the circularly polarized light c.

[0035] In this embodiment, the circularly polarized light generating device includes an elliptically polarized light generating system 100 and a polarization modulation system 200. The polarization modulation system 200 is located on the light-emitting side of the elliptically polarized light generating system 100. After the elliptically polarized light generating system 100 generates elliptically polarized light b, it is incident into the polarization modulation system 200. The polarization modulation system 200 applies periodically changing deflection modulation to the azimuth angle of the elliptically polarized light b to output elliptically polarized light b with periodically changing azimuth angles. After a period of superposition and accumulation, the elliptically polarized light b achieves the effect of integral averaging in all directions of the circumference of the elliptically polarized light b. The output polarized light is equivalent to circularly polarized light c. Therefore, by polarizing the elliptically polarized light b through the polarization modulation system 200, circularly polarized light c is generated. When using the circularly polarized light c for processing, the processing accuracy can be improved. Alternatively, when using the circularly polarized light c for optical experiments, signal distortion can be avoided, and the detection reliability of the circularly polarized light c can be improved.

[0036] By way of example and not limitation, the elliptically polarized light generation system 100 includes a laser emitting unit 110 and a first polarization conversion module 120. The first polarization conversion module 120 is disposed on the light-emitting side of the laser emitting unit 110. The laser emitting unit 110 is a linearly polarized light a laser emitting unit 110 used to generate linearly polarized light a. The linearly polarized light a is incident on the first polarization conversion module 120, and the first polarization conversion module 120 outputs elliptically polarized light b to obtain elliptically polarized light b.

[0037] By way of example and not limitation, the elliptically polarized light generation system 100 includes a light source, a linear polarization module, and a first polarization conversion module 120. The linear polarization module is located on the light-emitting side of the light source and is used to convert the light emitted by the light source into linearly polarized light a. The first polarization conversion module 120 is located on the light-emitting side of the linear polarization module. The linearly polarized light a is incident on the first polarization conversion module 120, and the first polarization conversion module 120 outputs elliptically polarized light b to obtain elliptically polarized light b.

[0038] It is understandable that the elliptically polarized light generation system 100 can also use other structures to generate elliptically polarized light b, which will not be listed here.

[0039] For example, the first polarization conversion module 120 is a quarter-wave plate. Based on the quarter-wave plate, linearly polarized light a can be decomposed into two directions, fast axis and slow axis. Therefore, after the linearly polarized light a passes through the quarter-wave plate, it outputs elliptically polarized light b.

[0040] In one possible implementation, the polarization modulation system 200 includes a rotation module 210 and a second polarization conversion module 220. The second polarization conversion module 220 is used to transmit elliptically polarized light b. The second polarization conversion module 220 is disposed on the rotation module 210. The rotation module 210 is configured to drive the second polarization conversion module 220 to rotate around the optical axis of the elliptically polarized light b at a target rotational speed, so as to output elliptically polarized light b with periodically changing azimuth angle.

[0041] In one possible implementation, the target rotational speed is N (revolutions per second), and the duration of a single application of circularly polarized light at a single processing point is T, N 2T is an integer, meaning that within the duration of a single action at a single processing point, the elliptically polarized light b rotates at a constant speed by an integer multiple of 0.5 revolutions, thus ensuring that the integral average effect of the projection of the elliptically polarized light b along the beam exit direction over time is equivalent to that of circularly polarized light.

[0042] For example, in laser processing scenarios, the processing point of circularly polarized light refers to a specific location on the target object to be processed. In some scenarios, it is necessary to process the processing location multiple times to obtain a hole structure, and the duration T of a single action refers to the duration of a single action on the processing location.

[0043] In laser experimental scenarios, the processing point of circularly polarized light refers to the polarization detection device, and the duration of a single action refers to the single response time of the polarization detection device.

[0044] As an example, the first polarization conversion module 120 and the second polarization conversion module 220 are arranged sequentially along the beam propagation direction. The linearly polarized light a emitted from the laser emitting unit 110 is incident on the first polarization conversion module 120. The first polarization conversion module 120 converts the linearly polarized light a into elliptically polarized light b. The elliptically polarized light b output by the first polarization conversion module 120 is incident on the second polarization conversion module 220. During rapid rotation, the second polarization conversion module 220 applies a periodically changing deflection modulation to the azimuth angle of the elliptically polarized light b, so as to output the elliptically polarized light b with a periodically changing azimuth angle.

[0045] As an example, the second polarization conversion module 220 is a half-wave plate. The half-wave plate is used to adjust the phase of the elliptically polarized light b, ensuring a phase difference of 180° (without changing the polarization state). High-speed rotation of the half-wave plate allows for rapid adjustment of the azimuth angle (or polarization position) of the elliptically polarized light b. Therefore, by applying periodically varying deflection modulation to the azimuth angle of the elliptically polarized light b using a half-wave plate, the projection of the elliptically polarized light b onto the beam exit direction can be rapidly adjusted. This ensures that the time-integral averaging effect of the projection of the elliptically polarized light b is equivalent to that of the circularly polarized light c, while maintaining the polarization state of the elliptically polarized light b.

[0046] As an example, the rotating module 210 includes a mounting base and a drive motor, with a second polarization conversion module 220 disposed within the mounting base. The drive motor is configured to drive the second polarization conversion module 220 to rotate. The rotation of the second polarization conversion module 220 is controlled at a constant speed by the drive motor.

[0047] One embodiment of this application also provides a laser processing device; please refer to the following: Figure 1 and Figure 2 It includes a circularly polarized light generating device and a worktable. The circularly polarized light generating device is used to generate circularly polarized light, and the worktable is located on the light-emitting side of the circularly polarized light generating device. The circularly polarized light is used to process the target object 300 on the worktable.

[0048] In this embodiment, the laser processing equipment includes the circularly polarized light generating device in the aforementioned embodiments. Therefore, the laser processing equipment has the same effects as the circularly polarized light generating device in the aforementioned embodiments.

[0049] As an example, the laser processing equipment also includes a controller configured to: determine a target rotational speed based on processing parameters corresponding to the target processing object 300, and control the rotation module 210 of the circularly polarized light generating device according to the target rotational speed, so as to drive the second polarization conversion module 220 of the circularly polarized light generating device to rotate around the optical axis of the elliptical polarized light at the target rotational speed. Here, the target processing object 300 is a workpiece processed using circularly polarized light c, for example, the target processing object 300 is a substrate.

[0050] It is understandable that when circularly polarized light c is used to process the target object 300, the rotation of the second polarization conversion module 220 causes the azimuth angle of the elliptically polarized light b to change at least one revolution during the processing. The elliptically polarized light b accumulated on the target object 300 during the processing superimposes to form circularly polarized light c.

[0051] Alternatively, an optical experiment can be conducted on the target object 300 using circularly polarized light c. The rotation of the second polarization conversion module 220 causes the azimuth angle of the elliptically polarized light b to change at least one revolution within the response time of the polarization detection device. The polarization detection device then senses the circularly polarized light c, formed by the superposition of the elliptically polarized light b accumulated within the response time. Therefore, based on the processing parameters corresponding to the target object 300, the second polarization conversion module 220 is controlled to rotate at the target rotation speed. The periodically changing azimuth angle of the elliptically polarized light b output by the second polarization conversion module 220 is projected along the beam emission direction onto the target object 300 to form circularly polarized light c, thus achieving the purpose of generating circularly polarized light c to process the target object 300.

[0052] As an example, the processing parameters include at least one of the hole depth, hole diameter, and target laser energy of the hole structure to be processed in the target object. The duration of a single action at a single processing position on the target object is determined based on the processing parameters. For example, if the required processing time is determined to be t1 based on the hole depth of the hole structure to be processed, and the number of processing operations is n1, then the duration of a single action T is t1 / n1, and the target rotational speed is determined based on the duration of the single action T.

[0053] In some embodiments, within the duration T of a single action, the azimuth angle of the elliptically polarized light b deflects at least one revolution to determine the target rotational speed N of the second polarization conversion module 220, wherein N T is an integer.

[0054] In some embodiments, a half-wave plate is used to deflect and modulate the elliptically polarized light b. Since the half-wave plate rotates 180° (i.e., half a revolution), the azimuth angle of the elliptically polarized light b is deflected by one revolution. For example, the target rotational speed of the second polarization conversion module 220 is M. (1 / 2T) revolutions per second, where M is a positive integer greater than 0, and T is the duration of a single action of circularly polarized light at a single processing point.

[0055] Taking drilling on a substrate as an example, if the target hole structure can be processed on the substrate in one laser drilling operation, and the laser drilling time T is 0.01s, then the target rotation speed is M. At 50 revolutions per second, the controller controls the rotating module 210 to drive the second polarization conversion module 220 at M... The laser rotates at a speed of 50 revolutions per second to apply periodically varying deflection modulation to the azimuth angle of elliptically polarized light b, outputting elliptically polarized light with periodically varying azimuth angles. The projection of this periodically varying elliptically polarized light along the beam's exit direction onto the substrate forms an equivalent circularly polarized light, thus achieving drilling with circularly polarized light c. If machining the target hole structure on the substrate requires two laser drilling operations, and the total drilling time t1 is 0.1s, while the time T for a single laser drilling operation is 0.05s, then the target rotational speed is M. 10 revolutions per second.

[0056] In one possible implementation, the polarization modulation system 200 includes an electro-optic polarization controller. The electro-optic polarizer is configured to adjust the relative phase and amplitude of two orthogonal polarization components to deflect and modulate the incident elliptically polarized light b, thereby changing the azimuth angle of the elliptically polarized light b. Exemplarily, the electro-optic polarization controller includes at least two electro-optic waveplates, utilizing electro-optic effects (such as the Pockels effect), and applying a driving voltage V to continuously change the phase difference in real time, causing the elliptically polarized light b to change periodically, thus achieving periodic polarization modulation of the elliptically polarized light b. Optionally, in this example, the modulation period of the polarization modulation is controlled by controlling the period of the driving voltage of the electro-optic modulator.

[0057] Figure 3 This is a schematic flowchart of a laser processing method provided in one embodiment of this application, applied to the circularly polarized light generating device or laser processing equipment in the foregoing embodiments. It is intended as an example and not a limitation. Figure 3 As shown, laser processing methods include: S301, Obtain the processing parameters of the target object, including the duration of a single action of circularly polarized light on a single processing point of the target object.

[0058] In laser processing scenarios, laser equipment is used to process target objects. In this embodiment, the laser equipment can generate circularly polarized light by controlling a circularly polarized light generating device. Therefore, when using the laser equipment for laser processing, the processing parameters required to generate circularly polarized light are obtained.

[0059] Optionally, the processing parameters include the duration of a single interaction of circularly polarized light with a single processing point on the target object. For example, a specific location on the target object to be processed is a single processing point of circularly polarized light, and the duration of a single laser processing operation at that location is the duration of the single interaction.

[0060] In one possible implementation, the duration of a single action is determined based on the processing parameters corresponding to the target object. For example, the target rotational speed of the second polarization conversion module of the laser processing equipment is determined based on the duration of a single action of circularly polarized light at a single processing point, including: determining the processing information corresponding to the target object of the laser processing equipment; and determining the duration of a single action at a single processing point of the target object based on the processing information.

[0061] Optionally, if a hole structure is being machined on a target object, the machining information includes at least one of the hole depth, hole diameter, and target laser energy of the hole structure to be machined on the target object. For example, the total laser machining time and the number of laser machining operations are determined based on the hole depth, and the duration of a single operation is determined based on the total laser machining time and the number of laser machining operations.

[0062] S302, Place the target object to be processed on the worktable.

[0063] S303 controls the circular polarization light generating device to generate circular polarization light according to the processing parameters, and uses the circular polarization light to perform laser processing on the target object on the worktable.

[0064] Laser processing equipment includes a circularly polarized light generator, which generates circularly polarized light and is used for drilling, cutting, or optical experiments. For example... Figure 1 As shown, the circularly polarized light generating device of this embodiment includes an elliptically polarized light generating system 100, a polarization modulation system 200, and a controller. The controller is electrically connected to the elliptically polarized light generating system 100 and the polarization modulation system 200.

[0065] Elliptically polarized light generation system 100 is used to generate elliptically polarized light, and polarization modulation system 200 is configured to apply periodically varying deflection modulation to the azimuth angle of the elliptically polarized light to output elliptically polarized light with periodically varying azimuth angle, wherein the integral averaging effect of the projection of the periodically varying elliptically polarized light along the beam exit direction over time is equivalent to that of circularly polarized light.

[0066] Therefore, controlling the circularly polarized light generating device to generate circularly polarized light according to processing parameters specifically includes: The elliptically polarized light generation system of the laser processing equipment generates elliptically polarized light.

[0067] The polarization modulation system of the laser processing equipment is controlled according to the processing parameters to apply periodically changing deflection modulation to the azimuth angle of the elliptically polarized light, so as to output elliptically polarized light with periodically changing azimuth angle. The integral averaging effect of the projection of the elliptically polarized light with periodically changing azimuth angle along the beam exit direction over time is equivalent to that of circularly polarized light.

[0068] For example, when the laser processing equipment receives a processing instruction, it controls the elliptically polarized light generation system 100 to generate elliptically polarized light. At the same time, it generates a control instruction for the polarization modulation system 200 according to the processing parameters, and controls the polarization modulation system 200 to apply periodically changing deflection modulation to the azimuth angle of the elliptically polarized light. This makes the elliptically polarized light emitted from the elliptically polarized light generation system 100, after passing through the polarization modulation system 200, project onto the target processing object in a manner equivalent to circularly polarized light. In other words, the target processing object is processed based on circularly polarized light.

[0069] Taking the application to laser-processed hole structures as an example, the laser processing equipment includes the circularly polarized light generating device, and the laser processing equipment controls the circularly polarized light generating device to generate circularly polarized light.

[0070] As an example, the polarization modulation system 200 includes a rotation module 210 and a second polarization conversion module 220, the second polarization conversion module 220 being disposed on the rotation module 210. Optionally, the rotation module 210 includes a mounting base and a drive motor, the second polarization conversion module 220 being disposed within the mounting base, and the drive motor being configured to drive the second polarization conversion module 220 to rotate. In this example, the laser processing equipment controls the drive motor to rotate, thereby causing the second polarization conversion module 220 to rotate.

[0071] In laser drilling scenarios involving target objects, drilling with circularly polarized light can achieve a hole depth greater than or equal to 500 micrometers, improving and optimizing the laser drilling structure. (Please refer to...) Figure 4 In laser processing, because the focused laser beam follows a hyperbolic propagation model, the focal area has the smallest spot size and the highest energy density. Further away from the focal point, the beam diverges, leading to a decrease in energy density. This causes the opening size of the laser beam along the penetration direction to continuously shrink, resulting in an inverted trapezoidal cross-section for the drilled hole. With greater hole depth, it can even become an inverted conical structure. In this case, if non-circularly polarized light is used for drilling, the anisotropic reflection of the ellipticized s-rays and p-rays on the sidewalls of the hole structure causes the cross-sectional structure of the drilled hole to shift to one side, such as... Figure 5 As shown, the inverted trapezoidal or inverted conical structure of the cross-section of the hole structure 310 will tilt. When the hole depth of the hole structure 310 to be processed increases, the tilt of the hole structure 310 becomes more obvious, and the bottom opening becomes smaller, resulting in large dimensional deviations of the upper and lower openings of the hole structure 310, as well as large deviations in the center position.

[0072] Based on this, for laser drilling scenarios with a hole depth greater than or equal to 500 micrometers, the laser processing method in the embodiments of this application is used for drilling. Using circularly polarized light for drilling can avoid the displacement of the cross-sectional structure of the drilled hole, that is, it can avoid the tilting of the hole structure.

[0073] In this embodiment, the circularly polarized light generation device includes an elliptically polarized light generation system and a polarization modulation system. The polarization modulation system is located on the light-emitting side of the elliptically polarized light generation system. After the elliptically polarized light generation system generates elliptically polarized light, the elliptically polarized light enters the polarization modulation system. By controlling the polarization modulation system to apply periodically changing deflection modulation to the azimuth angle of the elliptically polarized light, the polarization modulation system outputs elliptically polarized light with periodically changing azimuth angles. The superposition and accumulation of the projections of the periodically changing elliptically polarized light along the beam emission direction over time achieves the effect of integral averaging at various azimuth angles of the elliptically polarized light, which is equivalent to outputting circularly polarized light. Therefore, by applying periodically changing deflection modulation to the azimuth angle of the elliptically polarized light through the polarization modulation system, circularly polarized light is generated. When using this circularly polarized light for processing, processing accuracy can be improved; or when using this circularly polarized light for optical experiments, signal distortion can be avoided, and the detection reliability of the circularly polarized light can be improved.

[0074] Figure 6 This is a schematic flowchart of a laser processing method according to another embodiment of this application. Based on the foregoing embodiments, this embodiment provides a detailed description of the process of applying periodically varying deflection modulation to the azimuth angle of elliptically polarized light by controlling a polarization modulation system according to processing parameters. This is intended as an example and not a limitation. Figure 6 As shown, it includes: S601, determine the target rotational speed of the second polarization conversion module of the polarization modulation system based on the duration of a single action; In one possible implementation, the laser processing method is used to process a target object, for example, a substrate, on which laser drilling is performed.

[0075] The laser generated by the laser processing equipment is circularly polarized light. Therefore, a certain position on the target object to be processed is a single processing point of circularly polarized light, and the duration of one laser processing at that position is the duration of a single operation.

[0076] It is understandable that the relationship between the duration of a single action and the target rotational speed of the second polarization conversion module is as follows: within the duration of a single action T, the second polarization conversion module rotates at least 1 / 2 revolution. Therefore, the target rotational speed N is M / (2T), where M is a positive integer greater than 0.

[0077] As an example, the processing type is related to the number of rotations of the azimuth angle of elliptically polarized light, and the number of rotations is also obtained based on the processing type. For instance, when processing deep, elongated holes, the corresponding number of rotations is M1, and when conducting optical experiments with circularly polarized light, the corresponding number of rotations is M2, where M1 and M2 are different. When processing a target object using circularly polarized light, the rotation number of the second polarization conversion module is controlled differently for different processing types to modulate the circularly polarized light adapted to the corresponding processing type, thereby improving the processing quality of the target object and preventing the second polarization conversion module from rotating too fast and affecting the processing effect of the laser point.

[0078] S602 controls the rotation module of the polarization modulation system, which drives the second polarization conversion module to rotate around the optical axis of the elliptically polarized light at a target rotation speed, so as to output elliptically polarized light with periodically changing azimuth angle.

[0079] As an example, the polarization modulation system includes a rotation module and a second polarization conversion module, with the second polarization conversion module mounted on the rotation module. The rotation module is controlled to drive the second polarization conversion module to rotate at a target rotational speed, so that elliptically polarized light, after being modulated by the second polarization conversion module, outputs elliptically polarized light with a periodically changing azimuth angle. The integral averaging effect of the projection of the periodically changing elliptically polarized light along the beam exit direction over time is equivalent to that of circularly polarized light.

[0080] In this embodiment, the bias modulation module is controlled according to the processing parameters of the target object, so that the polarization modulation system deflects and modulates the azimuth angle of the elliptically polarized light to match the processing requirements of the target object, thus adapting to the processing requirements of the target object. By performing targeted deflection modulation, the different processing requirements of different target objects can be met.

[0081] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A circularly polarized light generating device, used for laser processing of a target object, characterized in that, include: Elliptically polarized light generation system, used to generate elliptically polarized light; A polarization modulation system is disposed on the light-emitting side of the elliptically polarized light generation system. The polarization modulation system is configured to apply periodically varying deflection modulation to the azimuth angle of the elliptically polarized light to output elliptically polarized light with periodically varying azimuth angle. The integral averaging effect of the projection of the periodically varying azimuth angle elliptically polarized light along the beam emission direction in time is equivalent to that of circularly polarized light.

2. The circularly polarized light generating device as described in claim 1, characterized in that, The polarization modulation system includes a rotation module and a second polarization conversion module. The second polarization conversion module is used to transmit the elliptically polarized light. The second polarization conversion module is disposed on the rotation module. The rotation module is configured to drive the second polarization conversion module to rotate around the optical axis of the elliptically polarized light at a target rotational speed to output the elliptically polarized light with periodically changing azimuth angles. The target rotational speed is N revolutions per second, and the duration of a single action of the circularly polarized light on the target processing object at a single processing point is T, N. 2T is an integer.

3. The circularly polarized light generating device as described in claim 2, characterized in that, The elliptically polarized light generation system includes: The laser emitter is used to generate linearly polarized light; The first polarization conversion module is disposed on the light-emitting side of the laser emitting unit and is used to convert the linearly polarized light into the elliptically polarized light.

4. The circularly polarized light generating device as described in claim 3, characterized in that, The first polarization conversion module is a quarter-wave plate, and the second polarization conversion module is a half-wave plate.

5. A laser processing device, characterized in that, include: The circularly polarized light generating apparatus as described in any one of claims 1 to 4, wherein the circularly polarized light generating apparatus is used to generate circularly polarized light; A worktable is located on the light-emitting side of the circularly polarized light generating device, and the circularly polarized light is used to process the target object on the worktable.

6. The laser processing equipment as described in claim 5, characterized in that, The laser processing equipment also includes a controller configured to: determine a target rotation speed based on the processing parameters corresponding to the target processing object, and control the rotation module of the circularly polarized light generating device based on the target rotation speed, so as to drive the second polarization conversion module of the circularly polarized light generating device to rotate around the optical axis of the elliptical polarized light at the target rotation speed.

7. A laser processing method, characterized in that, The laser processing method, applied to the laser processing equipment as described in claim 5 or 6, comprises: Obtain the processing parameters of the target object, the processing parameters including the duration of a single action of the positive circular polarized light on a single processing point of the target object; Place the target object to be processed on the worktable; The circularly polarized light generating device is controlled to generate circularly polarized light according to the processing parameters, and the circularly polarized light is used to perform laser processing on the target object on the worktable.

8. The laser processing method as described in claim 7, characterized in that, The step of controlling the circularly polarized light generating device to generate circularly polarized light according to the processing parameters includes: The laser processing equipment is controlled to generate elliptically polarized light through an elliptically polarized light generation system. According to the processing parameters, the polarization modulation system of the laser processing equipment is controlled to apply periodically changing deflection modulation to the azimuth angle of the elliptically polarized light, so as to output elliptically polarized light with periodically changing azimuth angle. The integral averaging effect of the projection of the periodically changing elliptically polarized light along the beam exit direction over time is equivalent to that of circularly polarized light.

9. The laser processing method as described in claim 8, characterized in that, The step of controlling the polarization modulation system of the laser processing equipment according to the processing parameters to apply periodically changing deflection modulation to the azimuth angle of the elliptically polarized light, so as to output elliptically polarized light with periodically changing azimuth angle, includes: Based on the duration of the single action, the target rotational speed of the second polarization conversion module of the polarization modulation system is determined, wherein the target rotational speed N is M / (2T), T is the duration of the single action, and M is a positive integer greater than 0; The rotation module of the polarization modulation system is controlled to drive the second polarization conversion module to rotate around the optical axis of the elliptically polarized light at the target rotation speed, so as to output the elliptically polarized light with periodically changing azimuth angle.

10. The laser processing method according to any one of claims 7-9, characterized in that, The laser processing method is used to perform laser drilling on the target object, wherein the depth of the laser-drilled hole is greater than or equal to 500 micrometers.

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