Characteristic of diffractive optical element for multi-spot beam homogenizing

摘要

Laser materials processing has been used increasingly over the wide area of electronic industries, especially for drilling microvias in printed circuit boards, and poly-silicon annealing for thin film transistor of liquid crystal display. To increase a processing speed, it has been developed a beam splitting element of a diffractive optical element (DOE). And the other hand, to obtain higher uniformity, because the intensity distribution of laser beam is usually a non-uniform Gaussian profile, beam homogenizer of a DOE has recently been developed and introduced to some promising applications. Through the improvement of optical design algorithms, micro-fabrication techniques of a phase pattern of DOE and new method of optical system, it enables to combine its beam splitting function and homogenizing function. It can produce the simultaneous multi-spot homogenized beam. In this investigation, we introduce a concrete design and fabrication result of multi-spot beam homogenizing system for SHG-YAG laser that can convert a Gaussian distribution into the plural number of uniformity intensity distribution, and present the possibility of new laser material processing by using such optics.