Method and system for high-speed precise laser trimming and scan lens for use therein

A system for high-speed, laser-based, precise laser trimming at least one electrical element having at least one measurable property, the at least one element being supported on a substrate, the system comprising:

• a laser subsystem to generate a pulsed laser output having one or more laser pulses at a repetition rate, each laser pulse having a pulse energy, a visible laser wavelength, and a pulse duration;
• a beam delivery subsystem that accepts the pulsed laser output and includes:
• at least one beam deflector to position the one or more laser pulses relative to the at least one element to be trimmed;
• and
• an optical subsystem to focus the one or more laser pulses having the visible laser wavelength into at least one spot within a field of the optical subsystem;
• the at least one spot having a non-uniform intensity profile along a direction and a spot diameter less than about 15 microns;
• and
• a controller coupled to the beam delivery and laser subsystems to control the beam delivery and laser subsystems to selectively irradiate the at least one element such that the one or more laser output pulses having the visible laser wavelength, the pulse duration, the pulse energy and the spot diameter selectively remove material from the at least one element and laser trim the at least one element along a trim path while avoiding substantial microcracking within the at least one element, the laser wavelength being short enough to produce desired short-wavelength benefits of small spot size, tight tolerance, high absorption and reduced or eliminated heat-affected zone (HAZ) along the trim path, but not so short so as to cause microcracking.

A multiple element achromatic scan lens configured to provide:

• a scan field encompassing a scan area of about 25 mm×50 mm;
• a green wavelength laser spot size less than 20 microns to about 8 microns or less, wherein a scan field diameter measures up to about 7000 spots;
• and
• a viewing channel with a bandwidth of at least 40 nm to 100 nm or more, wherein each element is composed of a glass type having an index of refraction, nn, and a dispersion, vn;
• the scan lens comprising in succession from a side of incident light:
• a first bi-concave element (L1);
• a first cemented doublet including plano-concave and bi-convex elements (L2, L3), a cemented surface of the first cemented doublet being concave away from the incident light, wherein n2<n3, v2>v3, and v2 represents an anomalous dispersion;
• a second cemented doublet including plano-concave and bi-convex elements (L4, L5), a cemented surface of the second cemented doublet being concave away from the incident light;
• a first negative meniscus element (L6) being concave toward the incident light;
• a first bi-convex element (L7);
• and
• wherein values of nn and vn for each glass element are characterized by the relationships:
• Index
• Dispersion
• L1
• n1 > 1.58
• v1 < 40
• L2
• 1.85 > n2 > 1.5
• v2 < 50
• L3
• n3 > 1.58
• v3 < 40
• L4
• n4 > 1.61
• v4 < 35
• L5
• 1.85 > n5 > 1.5
• v5 > 40
• L6
• n6 > 1.61
• v6 < 35
• L7
• 1.85 > n7 > 1.5
• v7 > 40