| 摘要 |
<p>A method for compensating an astigmatism induced by lens heating is provided to restrain the lowering of image contrast by compensating an astigmatism induced by lens heating. An astigmatism induced by lens heating is detected from a projection lens of an light-exposing apparatus using asymmetry modified illumination, and an active lens for compensating a wave front(602) of the projection lens is inserted into the projection lens. The eight points at the edges of the active lens are fixed by using fixing pins, and the edge portion is partially displaced in an upper or lower direction by applying physical forces to the four points among the eight points. The astigmatism is corrected by compensating the wave front.</p> |
