Laser methods for processing electrochromic glass

A material removal system comprising:

• a laser configured to produce a laser beam collimated to an angular divergence of 1 milliradian or less and comprising pulses of electromagnetic radiation having an energy density from 1 J/cm2 to 10 J/cm2 in a spot having a characteristic dimension of at least 5 mm at a first distance from the laser;
• and
• a workpiece holder configured to hold a surface of a workpiece at the first distance from the laser;
• wherein the material removal system is configured to provide the laser beam in a substantially collimated shape at the first distance from the laser.

A method of removing a material from a surface of a workpiece, the method comprising:

• directing a laser beam collimated to an angular divergence of 1 milliradian or less onto a first position on the surface of the workpiece, wherein the laser beam comprises pulses of electromagnetic radiation having at least two wavelengths, wherein the pulses of electromagnetic radiation form a spot that removes the material from the first position on the surface of the workpiece;
• moving the laser beam to a second position on the surface of the workpiece and removing the material from the second position on the surface of the workpiece;
• and
• moving the laser beam to one or more additional positions on the surface of the workpiece and removing the material from the one or more additional positions on the surface of the workpiece.

A material removal system comprising:

• a laser configured to produce a laser beam collimated to an angular divergence of 1 milliradian or less and comprising pulses of electromagnetic radiation having at least two wavelengths in a spot having a characteristic dimension of at least 5 mm at a first distance from the laser;
• and
• a workpiece holder configured to hold a surface of a workpiece at the first distance from the laser;
• wherein the material removal system is configured to provide the laser beam in a substantially collimated shape at the first distance from the laser.

A method of fabricating an optical device comprising a substrate and, sandwiched between a first conductive layer proximate to the substrate and a second conductive layer distal from the substrate, an electrochromic stack, the method comprising:

• (i) removing a first width of material from the second conductive layer and the electrochromic stack proximal to a perimeter of the substrate to a first depth sufficient to expose a portion of the first conductive layer;
• (ii) removing a second width, narrower than the first width, of material at a periphery of the substrate along substantially an entire perimeter of the substrate to a second depth, the second depth being at least sufficient to remove the first conductive layer;
• and
• (iii) applying a bus bar to the exposed portion of the first conductive layer;
• wherein removing the first width and removing the second width is performed with a laser beam collimated to an angular divergence of 1 milliradian or less and configured as pulses of electromagnetic radiation having an energy density from 1 J/cm2 to 10 J/cm2 in a spot having a characteristic dimension of at least 5 mm at a surface of the first conductive layer.