| 摘要 |
PURPOSE:To provide a titled device which improves airtightness and minimizes the deviation in an optical axis in holding a condenser lens one side of which is a blowing gas chamber by holding the top and bottom surfaces of the condenser lens via annular metallic foil having the curvature approximately equal to the curvature of said surfaces. CONSTITUTION:A condenser lens 2 in a lens barrel 3 is held by means of spacers 26, 27 and a retaining ring 4. Disc rings 23, 24 of aluminum or copper having <=50mu thickness and having the curvature approximately equal to the curvature of the lens 2 are interposed, whereby the airtightness with a lower air chamber is improved and the deviation in the optical axis is minimized. Handling is simpler than in the prior art and the need for consumable material is eliminated. |
