Patent ID: 7170912

Claim:
A laser drilling system for drilling via holes in a flexible printed circuit board, comprising: a first reflector; a second reflector, the first reflector and the second reflector being spaced apart from each other and cooperatively defining a resonator cavity; a laser crystal disposed in the resonator cavity for generating a fundamental laser beam; a second harmonic generator disposed in the resonator cavity for converting a portion of the fundamental laser beam into a second harmonic laser beam; a third harmonic generator disposed in the resonator cavity for converting a portion of the fundamental laser beam and the second harmonic laser beam into a third harmonic laser beam; and a prism disposed in the resonator cavity for separating the third harmonic laser beam from the fundamental laser beam and the second harmonic laser beam as an output laser beam; wherein the third harmonic laser beam has the following parameters: a wavelength of 355 nm; up to 5 watts output power; a beam quality M 2 value of less than 1.2; and a pulse width of 50 ns at 10 KHz.