Abstract: A projection optical apparatus includes a projection optical system including lenses, a measurement unit for measuring a change in the shape of one of the lenses, and an adjustment unit for adjusting the optical characteristics of the projection optical system in accordance with a signal from the measurement unit. Since a change in the shape of the lens due to a thermal change of the lens is directly measured and optical characteristics of the projection optical system are adjusted in accordance with the result of the measurement, projection can be performed with high stability and precision.

Abstract: A projective exposure apparatus for imaging a pattern formed on an original onto a substrate at a predetermined magnification to form a pattern image on the substrate includes an original support member, a substrate support member, and a projection lens disposed between these support members for imaging the pattern onto the substrate. In the projection exposure apparatus, a partial deviation of positions of portions of the pattern image from regular positions are obtained in at least one of the directions along and perpendicular to a surface of the pattern image, and the partial deviation is eliminated by deforming at least one of the original and the substrate based on the thus obtained result.

Abstract: Hydroxypropyl cellulose having superior solubility in isopropyl alcohol is obtained by reacting an alkali cellulose of unusually low NaOH/cellulose and water/cellulose ratios with propylene oxide in two stage successive reactions interposing an addition of water.