| 摘要 |
PURPOSE:To obtain an objective lens having good temperature characteristics by forming a supporting member for the objective lens by using alloy whose coefficient of heat expansion is nearly equal to that of the lens. CONSTITUTION:The objective lens device 45 consists of glass lenses 1, 2 and 3, a lens barrel 4, and a spacer 5. The lens barrel 4 and spacer 5 are formed of the alloy which are nearly equal in coefficient of heat expansion to the lenses and consists principally of ion and nickel. Consequently, the distortion due to heat expansion and shrinkage is reduced to obtain the objective lens with good temperature characteristics. |
