Laser cutting method using spatial light modulator and laser cutting device

A laser cutting device adopted to cut an object to be cut, comprising:

• a laser light source, adopted to emit a laser light;
• a spatial light modulator, disposed at a path of the laser light emitted by the laser light source, comprising a plurality of pixels;
• a laser cutting head, comprising an autofocus system, and further comprising:
• a focusing lens;
• and
• a water jacket disposed below the focusing lens, the water jacket comprising:
• a transparent window disposed on an upper lateral surface of the water jacket;
• a water inlet disposed on a lateral surface of the water jacket and configured to receive a liquid;
• and
• a nozzle disposed on a lower side surface of the water jacket, the nozzle being located in a vertical projection plane common with the transparent window and configured to spray the liquid toward the object to form a water column;
• a jig, adopted to fix an uncut object, which is to be cut;
• and
• a controller, electrically connecting to the laser light source, the spatial light modulator and the laser cutting head;
• wherein the laser light reflected by the pixels of the spatial light modulator passes through the laser cutting head to the object;
• wherein the laser light is irradiated onto the object by total reflection in the water column;
• wherein the controller detects a cutting depth of the object through the autofocus system of the laser cutting head;
• wherein the controller controls each of the pixels of the spatial light modulator in order to convert a phase of each of the laser light reflected by each of the pixels when the cutting depth reaches a first predetermined depth;
• and
• wherein the controller controls the jig or the laser cutting head to move when the cutting depth reaches a second predetermined depth.