| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a beam scanning type laser marking device suitable for forming fine dot marks for which visibility is secured. SOLUTION: In a beam scanning type laser marking device with which a marking is performed on a surface (MS) to be marked by being scanned with a laser beam emitted from a laser oscillator (1) at a predetermined pattern using a scanning mirror (5x, 5y) and by converging the laser beam through a conversion lens system (6 to 8), the conversion lens system (6 to 8) is constructed of three or more conversion type lenses. The focal length (fb1) of an fθlens (6) which is located at a position closest to the scanning mirror is so decided that the focal length does not interfere with a first scanning mirror (5x) which is placed opposite to the lens, the center of the first scanning mirror (5x) is placed at a position coincident with the front focal point (fb1) of the lens (6), and the elements of the conversion lens system (6 to 8) are successively placed in a telecentric relationship with each other. Thus, the deviation value of image formation is minimized and a dot interval which does not affect the visibility is secured even for fine dot marks.</p> |
