| 摘要 |
PURPOSE:To obtain a bright objective lens for optical disc consisting of two constituting lenses which is used most suitably when the distance between a light source and an information recording surface is short, by constituting the objective lens with the first lens which has a positive refracting power and has both of surfaces in the light source side and the image side formed to aspherical surfaces and the second lens having a positive refracting power and arranging the first and the second lenses in order from the light source side and satisfying specific conditions. CONSTITUTION:The objective lens consists of the first lens which has a positive refracting power and has both of surfaces in the light source side and the image side formed to aspherical surfaces and the second lens which has a positive refracting power, and the first and the second lenses are arranged in order from the light source side, and the condition of a formula is satisfied. This condition is given to determine distribution of the refracting power of the first lens and indicates the range where aberration is corrected effectively by making lenses aspherical. Thus, the bright lens is designed which has aberration corrected sufficiently as the objective lens for optical disc.
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