Laser cutting method and laser cutting device using a spatial light modulator

Abstract

A laser cutting method and a laser cutting apparatus using a spatial light modulator are disclosed. The laser cutting method using a spatial light modulator includes the following steps: (a) emitting a laser to a spatial light modulator, the spatial light modulator including a plurality of pixels; (b) irradiating an object to be cut with the laser modulated by the spatial light modulator to form a focal point and cutting the object; (c) measuring the cutting depth of the object; (d) when the cutting depth of the object reaches a first predetermined depth, the spatial light modulator changes the phase of each laser modulated by each pixel to change the light pattern distribution at the focal point; and (e) repeating steps (b) to (d) until the cutting depth of the object reaches a second predetermined depth; wherein the first predetermined depth varies with each cycle of steps (b) to (d). In addition, the present invention also provides a laser cutting apparatus suitable for cutting an object.

Description

Technical Field

[0001] This invention relates to a method for laser cutting of crystal pillars, and more particularly to a method for laser cutting of crystal pillars using a spatial light modulator. Background Technology

[0002] Ingot dicing is a common process in semiconductor manufacturing, mainly involving cutting microchips from ingots. Currently, wire dicing (such as piano wire) is used for this purpose. However, wire dicing results in a wider width, requiring larger dicing paths to be left on the ingot, and cutting larger pieces also means wasting more ingot substrate.

[0003] Furthermore, some components need to be manufactured using silicon carbide (SiC) or gallium nitride (GaN) wafers. SiC and GaN are more expensive, and larger dicing marks mean more investment is needed in the substrate being cut. Additionally, SiC is harder, and wire cutting can cause cracking on the cut surface, requiring further grinding.

[0004] Laser cutting is another option. Although laser cutting can effectively reduce the width of the cut track, traditional laser cutting has the disadvantages of high cost and difficulty in cutting crystal pillars.

[0005] In addition, please see Figure 1A and Figure 1B , Figure 1A The diagram shown is a microscopic illustration of laser cutting. Figure 1B The diagram shown is a graph illustrating the energy distribution of the laser. Figure 1B In the diagram, the vertical axis represents the laser's energy intensity, and the horizontal axis represents its horizontal position. When laser 11 is projected onto the object 10 to be cut, the laser beam appears concentrated, but in reality, the energy is still concentrated in the center of the beam and decreases outwards; this distribution is commonly referred to as a Gaussian distribution. When cutting in this manner, the physical properties of the object 10 at the energy concentration point will undergo significant changes due to thermal effects, such as changes in refractive index. This causes a slight deflection of the laser beam, resulting in an uneven cut surface.

[0006] For silicon carbide crystal ingot cutting, a stealth cutting method is used. This method utilizes a laser to penetrate and diffract optical elements, focusing the laser onto the interior of the object to be cut. The object dissolves internally, causing it to fracture along the crystal plane, thus achieving the cutting purpose. However, due to the dissolution of the internal material, the heat effect cannot be properly released, which also affects the laser focusing. As a result, the cut surface cannot form an ideal flat surface, requiring subsequent large-scale grinding to reinforce it.

[0007] Therefore, how to solve the problem of silicon carbide or gallium nitride ingot cutting is a question worth considering for those with general knowledge in this field. Summary of the Invention

[0008] The purpose of this invention is to provide a laser cutting method that generates different light pattern distributions through phase modulation. These different light pattern distributions can compensate for the thermal effects of materials and overcome the problem of uneven cut surfaces. The specific methods are as follows:

[0009] A laser cutting method includes the following steps:

[0010] (a) Emitting a laser to a spatial light modulator, the spatial light modulator comprising a plurality of pixels;

[0011] (b) Illuminate the object to be cut with the laser modulated by the spatial light modulator to form a focal point and cut the object;

[0012] (c) Measure the cutting depth of the object to be cut;

[0013] (d) When the cutting depth of the object to be cut reaches a first predetermined depth, the spatial light modulator changes the phase of each laser beam modulated by each pixel to change the light pattern distribution at the focal point; and

[0014] (e) Repeat steps (b) to (d) until the cutting depth of the object to be cut reaches a second predetermined depth;

[0015] The first predetermined depth varies with each cycle of steps (b) to (d).

[0016] In the laser cutting method described above, the object to be cut is a crystal pillar.

[0017] In the aforementioned laser cutting method, the crystal pillar is made of silicon carbide or gallium nitride.

[0018] In the aforementioned laser cutting method, the crystal pillar is fixed on a tool, and when the crystal pillar is cut by the laser, the tool rotates the crystal pillar.

[0019] The laser cutting method described above further includes step (a) of emitting a water jet toward the object to be cut; and step (b) of irradiating the object to be cut by total internal reflection in the water jet to cut the object.

[0020] In the aforementioned laser cutting method, the spatial light modulator is an LCOS device.

[0021] The laser cutting method described above, wherein step (a) includes:

[0022] (a1) Emit a laser to a beam expander;

[0023] (a2) Irradiate the spatial light modulator with the laser beam expanded by the beam expander.

[0024] The present invention also provides a laser cutting method, comprising the following steps:

[0025] (a) Emitting a laser to a spatial light modulator, the spatial light modulator comprising a plurality of pixels;

[0026] (b) Using the spatial light modulator, the laser is focused onto multiple focal points within the object to be cut;

[0027] The spatial light modulator dynamically changes the phase of each laser beam modulated by each pixel, thereby altering the light pattern distribution at each focal point.

[0028] In the aforementioned laser cutting method, the object to be cut is a transparent material.

[0029] In the laser cutting method described above, in step (b), the spatial light modulator is an LCOS device.

[0030] The present invention also provides a laser cutting apparatus suitable for cutting an object to be cut. The laser cutting apparatus includes a laser source, a spatial light modulator, a laser cutting head, a tool, and a controller. The laser source is adapted to emit a laser beam. The spatial light modulator is disposed in the path of the laser source and includes a plurality of pixels. The laser cutting head includes an autofocus system. The tool is adapted to fix the object to be cut. The controller is electrically connected to the laser source, the spatial light modulator, and the laser cutting head. The laser beam reflected by the pixels of the spatial light modulator passes through the laser cutting head and irradiates the object to be cut. The controller detects a cutting depth of the object to be cut via the autofocus system of the laser cutting head. When the cutting depth reaches a first predetermined depth, the controller controls the pixels of the spatial light modulator to change the phase of the laser beam reflected by each pixel. When the cutting depth reaches a second predetermined depth, the controller controls the tool or the laser cutting head to move.

[0031] The aforementioned laser cutting device further includes a focusing lens and a water jacket in the laser cutting head. The focusing lens is located below the laser cutting head. The water jacket is located below the focusing lens and includes a transparent window, a water inlet, and a nozzle. The transparent window is located on the upper surface of the water jacket. The water inlet is located on the side of the water jacket and is suitable for injecting a liquid. The nozzle is located on the lower side of the water jacket and is on the same vertical projection plane as the transparent window. The nozzle is suitable for directing the liquid toward the object to be cut. The laser irradiates the object to be cut within the liquid.

[0032] The aforementioned laser cutting device also includes a beam expander disposed in the path of the laser source.

[0033] In the aforementioned laser cutting device, the controller controls the rotation of the tool.

[0034] In the aforementioned laser cutting apparatus, the spatial light modulator is an LCOS device.

[0035] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the present invention. Attached Figure Description

[0036] Figure 1A The diagram shown is a microscopic illustration of laser cutting.

[0037] Figure 1B The diagram shown is an energy distribution map of the laser.

[0038] Figure 2A The illustration depicts a laser cutting method according to a first embodiment of the present invention;

[0039] Figure 2B The diagram shown is a schematic of the cutting device;

[0040] Figure 2C The diagram shown is a schematic of a spatial light modulator;

[0041] Figure 2D The diagram shown is an architecture diagram of the controller;

[0042] Figure 3A and Figure 3B A schematic diagram of the light pattern distribution at different depths;

[0043] Figure 3C The diagram shown illustrates the cutting depth.

[0044] Figure 4A The illustration shows a laser cutting method and schematic diagram according to the second embodiment;

[0045] Figure 4B The illustration shown is a laser schematic diagram of the second embodiment;

[0046] Figure 5 The diagram shown is a schematic of a water-guided laser;

[0047] Figures 6A to 6D The diagram shown is a cutting illustration;

[0048] Figure 7A The diagram shown is a cut surface image of traditional laser stealth cutting;

[0049] Figure 7B The diagram shown is a cutting surface view of the laser cutting method of the present invention.

[0050] Among them, the attached figures are labeled

[0051] 10: Item to be cut

[0052] 10': Cutting section

[0053] 11: Laser

[0054] 100: Laser cutting device

[0055] 101: Water Column

[0056] 110: Laser source

[0057] 111, 111a, 111b, 111b': Laser

[0058] 120: Beam expander

[0059] 130: Spatial light modulator

[0060] 131: pixels

[0061] 140: Laser cutting head with autofocus system

[0062] 151: Focusing lens

[0063] 152: Water Jacket

[0064] 153: Transparent Window

[0065] 154: Water inlet

[0066] 155: Nozzle

[0067] 156: Liquid

[0068] 156': Water column

[0069] 160: Controller

[0070] 161: Input Interface

[0071] 210: Tools

[0072] F1, F2, F3: Focus

[0073] FA, FB: Explosion Point

[0074] C: Axis

[0075] S11~S15, S21~S22: Flowchart Steps Detailed Implementation

[0076] The structural and working principles of the present invention will be described in detail below with reference to the accompanying drawings:

[0077] This invention provides a laser cutting method that uses a spatial light modulator to modulate the phase of the laser and control the location of laser energy concentration, overcoming the problem of uneven cut surfaces. Furthermore, this laser cutting method is suitable for application in a laser cutting apparatus 100. Please refer to [further details needed]. Figure 2B , Figure 2B The diagram shows a laser cutting apparatus. The laser cutting apparatus 100 includes a laser source 110, a beam expander 120, a spatial light modulator 130, multiple mirrors 101, a laser cutting head 140, a tool 210, and a controller 160.

[0078] Next, please refer to Figure 2A , Figure 2A The illustration depicts a laser cutting method according to a first embodiment of the present invention. First, step S11 is performed, in which a laser 111 is emitted to a spatial light modulator 130, the spatial light modulator 130 including a plurality of pixels 131. In this embodiment, a laser 111 is emitted from a laser source 110, and the laser 111 is first emitted to a beam expander 120. The laser 111a expanded by the beam expander 120 then irradiates the spatial light modulator 130.

[0079] For further details, please refer to Figure 2C , Figure 2C The diagram illustrates a spatial light modulator. A spatial light modulator is a liquid crystal on silicon (LCOS) device comprising multiple pixels 131. The LCOS controls the phase of the laser light reflected by each pixel 131. Due to phase modulation, the energy concentration point of the laser light 111b reflected by the LCOS changes, thus altering the light pattern distribution at the focal point.

[0080] Please return to the forum. Figure 2A and Figure 2B Next, in step S12, the laser 111b modulated by the spatial light modulator 130 is irradiated onto the workpiece 10 to be cut, forming a focal point and cutting the workpiece 10. In one embodiment, the laser 111b modulated by the spatial light modulator 130 is reflected by multiple mirrors 101 to adjust its direction and passes through a laser cutting head 140 with an autofocus system. The laser cutting head 140 with an autofocus system mainly focuses the laser 111b onto the workpiece 10 and provides cutting depth measurement. In this embodiment, the workpiece 10 is a crystal pillar, such as a silicon carbide or gallium nitride crystal pillar.

[0081] Please see Figure 5 , Figure 5The diagram illustrates a water-guided laser. In one embodiment, step S11 further includes emitting a water jet 156' directed toward the object to be cut 10. Step S12 further includes the laser irradiating the object to be cut by total internal reflection of the water jet 156', thereby cutting the object 10. In this embodiment, the laser cutting head 140 further includes a focusing lens 151 and a water jacket 152, with the water jacket 152 disposed below the focusing lens 151. The water jacket 152 includes a transparent window 153, a water inlet 154, and a nozzle 155. The transparent window 153 is disposed on the upper surface of the water jacket 152 and faces the focusing lens 151, while the nozzle 155 is disposed on the lower surface of the water jacket 152. Furthermore, the transparent window 153 and the nozzle 155 are on the same vertical projection plane. The inlet 154 is located on the side of the water jacket 152. Liquid 156 can be injected into the water jacket 152 through the inlet. Liquid 156 enters the water jacket 152 with a certain pressure column. Therefore, liquid 156 can be ejected through the nozzle 155 to form a water column 156' that is directed toward the object to be cut 10.

[0082] When the laser 111b is focused by the focusing lens 151 and directed towards the water jacket 152, it enters the water jacket 152 through the transparent window 153 and exits the water jacket 152 with the liquid 156 from the nozzle 155. At this time, the laser 111b' is reflected by the inner surface of the water column 156' and does not leave the water column 156'. In other words, the laser 111b can undergo total internal reflection inside the water column 156' before irradiating the object to be cut 10, which can effectively improve the focusing effect of the laser 111b. In addition, the water column 156' can also reduce the temperature generated when the object to be cut 10 is cut, and wash away the dust generated during cutting, maintaining the cleanliness of the cutting path.

[0083] Please return to the forum. Figure 2A and Figure 2B After laser 111b irradiates the object to be cut 10, cutting begins. After cutting begins, step S13 is performed to measure the cutting depth of the object 10. This cutting depth can be measured by measuring the light reflected from the object 10 by laser 111b using an autofocus system. When the cutting depth of the object 10 reaches a first predetermined depth, step S14 is performed, where the spatial light modulator 130 changes the phase of each laser modulated by each pixel 131 to alter the light pattern distribution at the focal point. Then, steps S13 to S14 are repeated until the cutting depth reaches a second predetermined depth. Furthermore, in one embodiment, a different first predetermined depth can be used each time steps S13 to S14 are repeated; that is, the first predetermined depth varies with each cycle of steps S13 to S14.

[0084] Please see Figure 1B , Figure 3A , Figure 3B and Figure 3C , Figure 3A and Figure 3B This is a schematic diagram of the light pattern distribution at different depths. Figure 3A and Figure 3B In the diagram, the vertical axis represents the energy intensity of the laser, and the horizontal axis represents the position in the horizontal direction. Figure 3C The diagram illustrates the cutting depth, represented by the cross-section of the laser and the object to be cut. In steps S13 and S14, firstly... Figure 1B The light pattern distribution is used to cut the workpiece 10, therefore corresponding to Figure 3C The energy concentration point is located on vertical line 21a. When the cutting depth reaches the first predetermined depth L1, the spatial light modulator 130 remodulates the laser 111b, modulating the light pattern distribution of the laser 111b, for example, as follows: Figure 3A As shown, continue cutting the object to be cut 10, therefore corresponding to Figure 3C The energy concentration point is located on vertical line 21b. When the cutting depth reaches the first predetermined depth L2, the spatial light modulator 130 modulates the laser 111b again, modulating the light pattern distribution of the laser 111b, for example, as follows: Figure 3B As shown, continue cutting the object to be cut 10, therefore corresponding to Figure 3C The energy concentration point is located on the vertical line 21c. When the cutting depth reaches the first predetermined depth L3, the overall cutting depth reaches the second predetermined depth L4. The second predetermined depth L4 is equivalent to the thickness of the object to be cut 10, that is, the laser 111b has penetrated the object to be cut 10. Then the laser cutting head 140 with an automatic focusing system or the object to be cut 10 can be moved along the cutting path (moved by a tool) to continuously cut the object to be cut 10 and recut the first predetermined depths L1 to L3.

[0085] In one embodiment, the multiple first predetermined depths L1 to L3 can be different depths, for example, the first predetermined depth L1 is 1 mm; the first predetermined depth L2 is 1.5 mm; and the first predetermined depth L3 is 2 mm. The sum of all the first predetermined depths is equivalent to the second predetermined depth. Furthermore, different combinations of first predetermined depths can be used for cutting at different cutting points before reaching the second predetermined depth. While the foregoing embodiment uses three first predetermined depths, it is not limited to this, and those skilled in the art will understand that different numbers of first predetermined depths can be set.

[0086] At each cutting depth, the laser 111b is modulated by the spatial light modulator 130 to change the position of the laser 111b energy concentration. This allows the laser 111b to avoid the heat-affected zone of the workpiece 10 to be cut, which can reduce the change in refractive index of the laser due to the heat-affected zone and improve the flatness of the cut surface.

[0087] Furthermore, a similar concept can also be applied to stealth cutting, as illustrated by further examples below. Next, please refer to... Figure 4A , Figure 4A The illustration shows a laser cutting method and schematic diagram according to the second embodiment. First, in step S21, a laser is emitted to a spatial light modulator, which includes multiple pixels 131. In this embodiment, the spatial light modulator is an LCOS, similar to the first embodiment, and will not be described again here. Next, in step S22, the laser is focused onto multiple focal points within an object to be cut using the spatial light modulator. The spatial light modulator dynamically changes the phase of each laser beam modulated by each pixel 131, thereby changing the light pattern distribution at each focal point. In this embodiment, the object to be cut is preferably a transparent material. Here, a transparent material refers to a material with a transmittance greater than 80% relative to the wavelength of the laser. Of course, those skilled in the art can also choose a material with lower transmittance as the object to be cut; that is, the object to be cut can be a transparent material or a non-transparent material.

[0088] Please see Figure 4B , Figure 4B The illustration shows a laser schematic of the second embodiment. Laser 111b passes through a laser cutting head 140 with an autofocus system and is projected onto a workpiece 10 to be cut. In this embodiment, laser 111b is focused at three focal points F1, F2, and F3, with one of these focal points, F1, falling on the surface of the workpiece 10. The light patterns at the focal points F1, F2, and F3 of laser 111b are all different (e.g., [missing information]). Figure 1B , Figure 3A and Figure 3B (The light pattern distribution). In this way, when dissolving focal points F1, F2, and F3, the different light pattern distributions can avoid the heat-affected zones generated by different focal points. Then, the object to be cut 10 is rotated. After the object to be cut 10 rotates once, the parts where focal points F1, F2, and F3 are dissolved will form a cross-section, and the object to be cut 10 will break and the cutting will be completed. Furthermore, since the light pattern distributions of focal points F1, F2, and F3 are all different, the heat-affected zones are avoided, and the resulting cross-section will be smoother.

[0089] In addition, Figure 4B In one embodiment, although the focal point F1 is located on the surface of the object to be cut 10, it is not limited to this. In other embodiments, the focal point F1 can also be located below the surface of the object to be cut 10, that is, the focal points F1, F2 and F3 are all located below the surface of the object to be cut 10.

[0090] Please see Figure 7A and Figure 7B , Figure 7A The diagram shown is a cut surface diagram of traditional laser stealth cutting. Figure 7BThe diagram shown is a cutting surface view of the laser cutting method of the present invention. Please refer to [link / reference]. Figure 7A , Figure 7A Cutting is performed using a traditional multi-focus, in-phase laser. However, because the thermal effect of the material being cut (10) during melting affects the laser's focusing position, a multi-focus, in-phase laser cannot actually achieve a neat alignment of focal points. Therefore, from... Figure 7A As can be seen, the cut surface is not smooth, and the focal points (FAs) of the laser beam are arranged very randomly. Next, please refer to... Figure 7B , Figure 7B When the laser cutting method of this invention is used for cutting, it can be seen that the flatness of the cut surface is significantly improved, and the FB spots on the cut surface are arranged much more neatly.

[0091] Please see Figure 2D , Figure 2D The diagram illustrates the architecture of the controller. The laser cutting method of the present invention can be controlled by a controller 160, which is electrically connected to the laser source 110, the spatial light modulator 130, the laser cutting head 140, and the tool 210. The controller 160 is a programmable logic controller (PLC) or a computer device with control capabilities, and also includes an input interface 161. The input interface 161 is adapted to input a control command, and the controller 160 receives the control command and controls the laser source 110 and the spatial light modulator 130 according to the control command. The input interface 161 may be, for example, a keyboard or a touch screen.

[0092] Furthermore, the controller 160 controls the output power of the laser source 110 and the pixels of the spatial light modulator 130. In a preferred embodiment, the control commands include multiple first cutting depths and second cutting depths, and the controller 160 calculates control parameters corresponding to the cutting depths, thereby adjusting the output power of the laser source 110 and controlling the pixels of the spatial light modulator 130. In addition, the controller 160 can also control the laser cutting head 140 and the tool 210 to adjust the laser irradiation position (i.e., the cutting position) on the object to be cut 10. The controller 160 controls the laser cutting head 140 to move to adjust the cutting position, or controls the tool 210 to move or rotate to control the position of the object to be cut 10.

[0093] Please see Figures 6A to 6D , Figures 6A to 6D The diagram shown is a schematic representation of the cutting process. Figures 6A to 6D In this embodiment, the laser cutting method of the present invention is applied to a cutting device. Therefore, the cutting device is suitable for cutting an object 10 to be cut, and the cutting device includes a laser cutter and a tool 210. To keep the drawings simple, in... Figures 6A to 6DOnly the laser cutting head 140 with an autofocus system of the laser cutter is shown in the diagram. The tool 210 is, for example, a clamp adapted to hold the workpiece 10 to be cut, positioning it below the laser cutting head 140 with the autofocus system. Furthermore, the tool 210 is also adapted to rotate the workpiece 10 during the cutting process. And, in Figures 6A to 6D In one embodiment, the object to be cut 10 is a cylindrical material.

[0094] Please refer to the following first. Figure 6A The object to be cut 10 is fixed below the laser cutting head 140 with an autofocus system by the tool 210, and the laser 111b passing through the laser cutting head 140 with an autofocus system is projected onto the object to be cut 10. Next, please refer to... Figure 6B The laser 111b has been modulated by the spatial light modulator 130, so it can pass through the object to be cut 10 with different light patterns to form a cutting depth. In this embodiment, the cutting depth is equivalent to the radius of the object to be cut 10.

[0095] Next, please refer to Figure 6D When the cutting depth reaches the second predetermined cutting depth, tool 210 rotates the object to be cut 10 about axis C. During this time, laser 111b continues to dissolve material radially from the object to be cut 10 until the object to be cut 10 has rotated one full circle (360 degrees). Next, please refer to... Figure 6D When the object to be cut 10 is rotated once, the material in the radial direction of the object to be cut 10 is removed, and the cutting part 10' will break, thus achieving the cutting effect.

[0096] The laser cutting method of the present invention modulates the laser using a spatial light modulator 130, allowing the modulated laser to irradiate the workpiece 10 to be cut with different light patterns. Figure 7B As can be seen, laser cutting with different light pattern distributions significantly improves the flatness of the cut surface.

[0097] Therefore, the laser cutting method of the present invention uses multi-phase laser to complete the cutting, which occupies a smaller cutting track area, is less likely to generate debris splash, and can further overcome the disadvantage of uneven cutting surface of traditional stealth laser cutting technology.

[0098] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the appended claims.

Claims

1. A laser cutting method, characterized in that, Includes the following steps: (a) Emitting a laser to a spatial light modulator, the spatial light modulator comprising a plurality of pixels; (b) Illuminate the object to be cut with the laser modulated by the spatial light modulator to form a focal point and cut the object; (c) Measure the cutting depth of the object to be cut; (d) When the cutting depth of the object to be cut reaches a first predetermined depth, the spatial light modulator changes the phase of each laser beam modulated by each pixel to change the light pattern distribution at the focal point; and (e) Repeat steps (b) to (d) until the cutting depth of the object to be cut reaches a second predetermined depth; The first predetermined depth varies with each iteration of steps (b) to (d).

2. The laser cutting method according to claim 1, characterized in that, The object to be cut is a crystal pillar.

3. The laser cutting method according to claim 2, characterized in that, The crystal pillar is made of silicon carbide or gallium nitride.

4. The laser cutting method according to claim 2, characterized in that, The crystal pillar is fixed to a tool, which rotates the crystal pillar when it is cut by the laser.

5. The laser cutting method according to claim 1, 2, or 4, characterized in that, Step (a) further includes: launching a jet of water toward the object to be cut; Step (b) involves the laser irradiating the object to be cut by total internal reflection in the water column, thereby cutting the object.

6. The laser cutting method according to claim 1, characterized in that, This spatial light modulator is an LCOS device.

7. The laser cutting method according to claim 1, characterized in that, (a) The steps include: (a1) Emit a laser to a beam expander; (a2) Irradiate the spatial light modulator with the laser beam expanded by the beam expander.

8. A laser cutting method, characterized in that, Includes the following steps: (a) Emitting a laser to a spatial light modulator, the spatial light modulator comprising a plurality of pixels; (b) Using the spatial light modulator, the laser is focused onto multiple focal points within the object to be cut, the multiple focal points being arranged along a cutting direction; The spatial light modulator dynamically changes the phase of each laser beam modulated by each pixel, thereby altering the light pattern distribution at each focal point.

9. The laser cutting method according to claim 8, characterized in that, The object to be cut is a transparent substance.

10. The laser cutting method according to claim 8, characterized in that, In step (b), the spatial light modulator is an LCOS device.

11. A laser cutting apparatus utilizing the laser cutting method of claim 1, suitable for cutting an object to be cut, characterized in that, The laser cutting device includes: A laser source, suitable for emitting a laser; A spatial light modulator is disposed in the path of the laser source, and the spatial light modulator includes multiple pixels; A laser cutting head, including an autofocus system; A tool suitable for fixing the object to be cut; and A controller is electrically connected to the laser source, the spatial light modulator, and the laser cutting head; The laser reflected by the pixel of the spatial light modulator passes through the laser cutting head and irradiates the object to be cut. The controller detects a cutting depth of the object to be cut via the autofocus system of the laser cutting head; When the cutting depth reaches a first predetermined depth, the controller controls the pixel of the spatial light modulator to change the phase of the laser reflected by each pixel; When the cutting depth reaches a second predetermined depth, the controller controls the tool or the laser cutting head to move.

12. The laser cutting apparatus according to claim 11, characterized in that, The laser cutting head also includes: A focusing lens is positioned below the laser cutting head; and A water jacket, positioned below the focusing lens, further includes: A transparent viewing window is provided on the upper surface of the water jacket; An inlet is located on the side of the water jacket, suitable for injecting a liquid; and A nozzle is located on the lower side of the water jacket and is on the same vertical projection plane as the transparent window. The nozzle is adapted to spray the liquid toward the object to be cut. The laser irradiates the object to be cut by total internal reflection in the liquid.

13. The laser cutting apparatus according to claim 11 further includes a beam expander disposed in the path of the laser source.

14. The laser cutting apparatus according to claim 11, characterized in that, The controller is used to control the rotation of the tool.

15. The laser cutting apparatus according to claim 11, characterized in that, This spatial light modulator is an LCOS device.

Images