| United States Patent | 5,783,798 |
| Abraham | Jul. 21, 1998 |
| Inventors: | Abraham; Martin (Hod Hasharon, IL). |
| Assignee: | Laser Industries Ltd. (Tel Aviv, IL). |
| Appl. No.: | 574,551 |
| Filed: | Dec. 19, 1995 |
| Dec. 21, 1994 [IL] | 112108 |
| Intl. Cl. : | B23K 26/00 |
| Current U.S. Cl.: | 219/121.73; 219/121.76; 606/13 |
| Field of Search: | 219/121.73, 121.75, 121, 76, 121.74; 606/4, 9, 10, 13, 14; 359/690, 694 |
| 4,312,572 | Jan., 1982 | Yamashita et al. | 359/690 |
| 4,353,617 | Oct., 1982 | Tokumitsu | 359/694 |
| 4,597,380 | Jul., 1986 | Raif et al. | 606/14 |
| 5,313,042 | May, 1994 | Matsuyama et al. | 219/121.74 |
| 5,449,879 | Sept., 1995 | Lawson et al. | 219/121.74 |
| 5,475,197 | Dec., 1995 | Wrobel et al | 219/121.75 |
| 5,558,666 | Sept., 1996 | Dewey et al. | 606/13 |
| WO 95/19147 | Jul., 1995 | WO |
A method of delivering a laser beam from a laser to a working site, comprising applying the laser beam received from the laser to a first positive optical element which converges the laser beam; applying the laser beam received from the first positive optical element to a negative optical element which diverges the laser beam; applying the laser beam received from the negative optical element to a second positive optical element which substantially collimates the laser beam before being applied to the working site; and varying the distance between the negative optical element and the second positive optical element to thereby vary the diameter of the substantially collimated laser beam applied to the working site.