・This section explains optimization of the shape of the laser beam energy distribution generated by splitting a laser beam into several beams in order to improve operational stability during continuous processing for long hours.

・While splitting a single laser beam into four beams for processing requires boosting up the power of the laser oscillator, important concerns for the engineer in charge are controlling investments and avoiding over-engineered designs as much as possible.

・And it is preferable to optimize the energy shape of the laser beam because an unexpected problem (such as damage to the laser beam shaping slitter, or damage to the table caused by the transmitted light) may occur caused by the transmitted light or the reflected light if the energy of the laser beam is too intense.

・Fig.1 illustrates the relationship between the shape of the laser beam and the allowable width for positional deviation of the laser beam required for maintaining machining quality.Fig 1 leads to the following formula for an allowable width for positional deviation of the laser beam:

・Positions of components on the light path needed to be re-adjusted for correct alignment because the beam position may shift over time due to ambient temperature changes, etc. in the light path system for laser beam.Optimization of the shape of the laser beam which allows an increase in the allowable width (W) for deviation in Formula (A) reduces positional correction for the beam and ensures continuous and stable processing for long hours.

・This requires techniques for optimizing distribution of energy density of the split laser beam (such as techniques for optimizing from Gaussian distribution-shaped beam for tophat-shaped beam, as shown in Fig.2).