| US 7,538,856 B2 | ||
| Illumination optical system and exposure apparatus including the same | ||
| Kazuhiko Kajiyama, Utsunomiya (Japan); and Toshihiko Tsuji, Utsunomiya (Japan) | ||
| Assigned to Canon Kabushiki Kaisha, Tokyo (Japan) | ||
| Filed on Jul. 24, 2008, as Appl. No. 12/179,506. | ||
| Claims priority of application No. 2007-195929 (JP), filed on Jul. 27, 2007. | ||
| Prior Publication US 2009/0027641 A1, Jan. 29, 2009 | ||
| Int. Cl. G03B 27/54 (2006.01); G03B 27/42 (2006.01) | ||
| U.S. Cl. 355—67 [355/53] | 6 Claims |
| 1. An illumination optical system comprising:
a first optical unit that collects light emitted from a light source;
a reflective integrator that has a plurality of cylindrical reflection surfaces, whose generating lines are oriented in a
uniform direction, and forms a plurality of linear light sources by using the light emitted from the first optical unit;
a pair of flat mirrors that are disposed parallel to the generating lines so as to face each other with the plurality of linear
light sources residing therebetween;
an aperture stop that is disposed perpendicular to the generating lines and has an opening for allowing the light emitted
from the plurality of linear light sources to pass therethrough; and
a second optical unit that integrates beams of the light emitted from the plurality of linear light sources that have passed
through the opening one on top of another in an illumination target plane.
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