CROSS SECTION EDGE NON-PROCESSING MIRROR SURFACE CUTTING METHOD

PROBLEM TO BE SOLVED: To solve the problems in cutting of a brittle transparent body that, after cutting, breaking strength of a product is weak because of stress concentration on a micro-crack generated on a cross section edge, and that a processing mark on a cross section is dirty.SOLUTION: Cutting with an industrially utilizable laser beam is performed as follows. A plurality of fine laser beam focal points arranged in series in a depth direction are generated successively from a deep point at a time difference, modified to be impermeable so as to absorb light, and a crack length is increased by interaction therebetween, and a focal point position is moved in a cut depth direction at high speed, to thereby elongate a cut depth without processing the edge part of a cut cross section, and to obtain a mirror surface cross section and high breaking strength.SELECTED DRAWING: Figure 3 【課題】 脆性透明体の切断は、切断後、断面端部に生成するマイクロクラックにおける応力集中により製品の破断強度が弱く断面の加工痕が汚いなどの問題があった。【解決手段】深さ方向に直列した微細な複数のレーザービーム焦点を時間差を置いて深いところから順次生起させ不透過性に変性させ光吸収を図り、それら相互作用により亀裂長さを増大させるとともに、焦点位置を切断深さ方向に高速で移動させることにより切断断面の端部を加工することなく切断深さを長くすることにより鏡面断面と高い破壊強度の得られるように産業利用可能なレーザーで切断。【選択図】 図３