METHOD AND OPTICAL UNIT FOR ADJUSTING CONVERGENCE STATE OF LIGHT OF SHORT ARC DISCHARGING LAMP BY ELLIPTIC CONVERGING MIRROR

摘要

PURPOSE:To adjust the position of a lamp with a simple device by displacing and adjusting the short arc discharging lamp so that a displayed photocurrent value is a certain value up to a maximum value. CONSTITUTION:The arc of the lamp 3 arranged in a light irradiation unit 10 is positioned at the 1st focus point F1 of the elliptic converging mirror 4. The arm of this lamp 3 is reflected by the elliptic converging mirror 4 and a plane mirror 6 and imaged on a photoelectric conversion element 23 arranged in the optical unit 20 for converged state adjustment. The photoelectric conversion element 23 which is arranged in the unit 20 and supported and fixed to an element fitting plate 24 is positioned at the position of the 2nd focus F2 of the converging mirror 4. Further, a pinhole plate 21 is screwed in the lens barrel 27 of the unit 20. Then a filter 22 is arranged inside the plate 21. When the lamp 3 is replaced, a three-dimensional position adjusting mechanism 5 is operated to position the arm of the lamp 3 at the position of the focus F1 of the converging mirror 4. Namely, the photocurrent value of the element 23 is maximized. Further, the photocurrent value can be fixed at a certain specific value right before the maximum value.