Processing of material using non-circular laser beams

Method for processing of material by use of a pulsed laser, the material being transparent or semi-transparent regarding a wavelength of the pulsed laser, the method comprising:

• generating a series of ultra-short laser pulses with pulse durations of less than 1 ns;
• directing each laser pulse to the material with defined reference to a respectively assigned processing point of a processing path;
• focusing each laser pulse so that respective focal points of the focused laser pulses comprise pre-defined spatial relations to a first surface of the material, wherein each emitted laser pulse effects a respective crack within the material;
• shaping each laser pulse regarding its beam profile so that a cross sectional area, which is defined by a cross section of the laser pulse in its focal point orthogonal to its propagation direction, is of a particular shape and has a main extension axis of significantly greater extent than a minor extension axis which is orthogonal to the main extension axis;
• effecting one major micro-crack by each laser pulse, the major micro-crack having a lateral extent basically oriented according to the orientation of the main extension axis of the respective pulse in the focal point and significantly greater than the extent of the respective main extension axis of the cross sectional areas in the focal point, the lateral extent is in a range of 3-30 times the length of the respective main extension axis;
• emitting each laser pulse so that the orientation of its main extension axis in the focal point corresponds to a pre-defined orientation relative to an orientation of a respective tangent to the processing path at the assigned processing point;
• and
• generating a burst of laser pulses with a defined burst energy, the burst of laser pulses being directed at a designated processing point on the material, wherein a defined inducement and propagation of a respective major micro-crack in the material is provided, wherein the burst energy is of at least 10 μJ, wherein the laser pulses of the burst are generated:
• with a pulse-to-pulse time lag in a range of 1 to 100 ns, or in a range of 10 to 20 ns, wherein the burst effects the micro-crack in the material with an extension as to the direction normal to the surface of the material in a range of 10 to 150 μm, or in a range of 40 to 100 μm, and/or
• comprising a defined power profile, the power profile being defined by:
• an exponential decay of pulse energies of the pulses of the laser burst, wherein the energy of an initial burst pulse is in a range of 15% to 30% of the burst energy, or in a range of 20% to 25% of the burst energy;
• or
• an exponential increase of pulse energies of the pulses of the laser burst;
• or
• constant pulse energies with respect to the pulses of the laser burst;
• and/or
• comprising a defined pulse duration profile defined by:
• a pulse-to-pulse increase of pulse durations of the pulses of the laser burst;
• or
• a pulse-to-pulse decrease of pulse durations of the pulses of the laser burst decay;
• or
• both a pulse-to-pulse increase and decrease of pulse durations during one burst of laser pulses with defined increasing and decreasing rates.

Method for processing of material by use of a pulsed laser, the material being transparent or semi-transparent regarding a wavelength of the pulsed laser, the method comprising:

• generating a series of ultra-short laser pulses with pulse durations of less than 1 ns;
• directing each laser pulse to the material with defined reference to a respectively assigned processing point of a processing path;
• focusing each laser pulse so that respective focal points of the focused laser pulses comprise pre-defined spatial relations to a first surface of the material, wherein each emitted laser pulse effects a respective crack within the material;
• shaping each laser pulse regarding its beam profile so that a cross sectional area, which is defined by a cross section of the laser pulse in its focal point orthogonal to its propagation direction, is of a particular shape and has a main extension axis of significantly greater extent than a minor extension axis which is orthogonal to the main extension axis;
• effecting one major micro-crack by each laser pulse, the major micro-crack having a lateral extent basically oriented according to the orientation of the main extension axis of the respective pulse in the focal point and significantly greater than the extent of the respective main extension axis of the cross sectional areas in the focal point, the lateral extent is in a range of 3-30 times the length of the respective main extension axis;
• emitting each laser pulse so that the orientation of its main extension axis in the focal point corresponds to a pre-defined orientation relative to an orientation of a respective tangent to the processing path at the assigned processing point;
• and
• directing the laser pulses so that a lateral distance with reference to the focal points between at least two of the laser pulses which are successively emitted is equal to or greater than an average of the lateral lengths of the major micro-cracks effected thereby, wherein:
• the main extension axis of each pulse is between 2 micro-meters and 3 micro-meters, the effected major micro-crack has a lateral length in the range of between 10 micro-meters and 60 micro-meters, and the laser pulses are directed with a distance with reference to the focal points between the at least two of the laser pulses which are successively emitted between 10 micro-meters and 60 micro-meters.