System and method of laser drilling

A method of producing a laser milled workpiece with a picosecond laser system, the method comprising:

• producing a picosecond laser beam;
• diffracting the picosecond laser beam, thereby illuminating at least one workpiece with a plurality of sub-beams;
• and
• performing a traversal of an exposed surface of the workpiece with the sub-beams, thereby ablating the exposed surface.

A method of controlling light beam intensity distribution in a laser drilling system comprising:

• determining an intensity distribution of a plurality of sub-beams provided by a source of sub-beams;
• constructing a microfilter based on the intensity distribution;
• and
• positioning the constructed microfilter within an optical path of the plurality of sub-beams.

A method of designing a microfilter to control beam intensity, the method comprising:

• determining an intensity distribution of a plurality of sub-beams provided by a source of sub-beams;
• calculating transmission values of partially transmissive filters for individual beams;
• and
• designing the physical layout of the microfilter.

An apparatus for controlling light beam intensity, the apparatus comprising:

• a substrate further including:
• a) a plurality of optical coatings;
• and
• b) a plurality of partially transmissive filters.

A method for correcting reflection angles from a PZT scan mirror comprising:

• calculating a reflection correction measure based on an incident angle;
• incorporating the reflection correction measure into a tool path algorithm;
• and
• operating the scan mirror with reflection correction to a tool path of the tool path algorithm.

A method for correcting hysteresis effect in a PZT scan mirror comprising:

• calculating a hysteresis correction measure based on a determined voltage response for a drilling run;
• incorporating the hysteresis correction factor into a tool path algorithm;
• and
• operating the scan mirror with hysteresis correction to a tool path of the tool path algorithm.

A method for operating a PZT scan mirror comprising:

• calculating a reflection correction measure based on an incident angle;
• calculating a hysteresis correction measure based on a determined voltage response for a drilling run;
• incorporating the reflection correction measure and hysteresis correction measure into a tool path algorithm;
• and
• operating the scan mirror with reflection correction and hysteresis correction to a tool path of the tool path algorithm.

A laser micromachining system comprising:

• a picosecond laser operable to produce a laser beam to illuminate a workpiece;
• a beam path describing a route of the laser beam from said picosecond laser to the workpiece;
• a scan mirror intersecting the beam path and operable to guide the laser beam to achieve a desired shape in the workpiece;
• a diffractive optical element intersecting the beam path and operable to diffract the laser beam, thereby producing a plurality of sub-beams illuminating a workpiece;
• a scan lens intersecting the sub-beams and operable to determine a spot size of the sub-beams upon the workpiece;
• a microfilter intersecting the sub-beams and operable to equalize an intensity distribution of the sub-beams;
• and
• a control module operable to:
• a) calculate a reflection correction measure based on an incident angle;
• b) calculate a hysteresis correction measure based on a determined voltage response for a drilling run;
• c) incorporate the reflection correction measure and hysteresis correction measure into a tool path algorithm;
• and
• d) operate said scan mirror with reflection correction and hysteresis correction to a tool path of the tool path algorithm.