System and method for employing a resonant scanner in an X-Y high speed drilling system

Abstract

A laser processing system is disclosed for providing a relatively small velocity of a laser beam at target location while at least one scanner scans at a relatively larger velocity. The system includes a laser source, a first scanning unit, a beam expander, a second scanning unit and focusing optics. The laser source is for providing a pulsed laser output having at least one beam with a beam dimension. The first scanning unit is for scanning the laser output in a first direction along a first axis at the target location. The beam expander is for receiving the laser output and for modifying a beam diameter of the laser output and providing a modified laser output. The second scanning unit is for scanning the modified laser output from the beam expander in a second direction along the first axis at the target location. The second direction is substantially opposite to the first direction along the first axis such that a net velocity of the modified laser output along the first axis at the target location may be made to be effectively zero during a laser pulse. The focusing optics is for focusing the modified laser output toward the target location.

Description

[0001] priority [0002] This application claims priority to US Provisional Patent Application Serial No. 60 / 839,211, filed August 22, 2006. technical field [0003] The present invention relates generally to laser processing systems for providing drilled holes in printed circuit boards, and more particularly to such laser processing systems providing improved speed and accuracy in the processing of printed circuit boards. Holes may be used to provide paths (or vias) through the circuit board. Background technique [0004] It is known that laser drilling is often performed using a laser beam positioned with an optical scanner, such as a galvanometer optical scanner. Galvanometric optical scanners typically include a scanning mirror coupled to a limited rotation motor. Such scanners are commonly referred to as "galvanometers" or "galvanometer scanners," and examples of such scanners are disclosed in US Patent No. 6,424,632, assigned to the assignee of the present invention....

AI Technical Summary

Problems solved by technology

For this reason, the speed at which multiple holes can be drilled is limited by the response rate of the positioning system, not by the laser power

Finite limited The stopping performance of a motor is usually limited by the resonant frequency, while the stepping rate (step and stop) is limited by the efficiency of the motor

However, increasing the bandwidth of a motor is constrained by the fact that the power dissipated (e.g. in the form of heat) in a finite rotating motor is proportional to the fifth power of the speed

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