| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide enhance the NA up to at least a refractive index proximity to the refractive index of glass used in a final lens, in an immersion optical system. <P>SOLUTION: The immersion optical system focuses light 10 from a light source toward a first surface 13a and comprises a lens 11, of which a lens surface 11a closest to the first surface is a concave face and liquid 12 which fills a light transmitting region between the lens surface and the first surface. The immersion optical system satisfies the condition: d>L/[2×tanäarcsin(NA/ni)}], where (d) is the distance between a first point and a second point, when the first point 11b on the lens surface and a second point 13b on the first surface becomes maximum in the direction approximately vertical with respect to the first surface, L/2 is the maximum distance from the second point up to the end of a light illumination region L on the first surface, NA is numerical aperture of the optical system and ni is the refractive index of the liquid. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
