Abstract: The present invention relates to a novel compound 5-pyrrolyl-6-halogeno-2-pyridylmethylsulfinylbenzimidazole derivative having the following formula (I): ##STR1## or a pharmaceutically acceptable salt thereof, in which X represents S, SO or SO.sub.2,Y represents halogen,R.sub.1 and R.sub.2 independently from each other represent hydrogen or methyl,R.sub.3 represents hydrogen, C.sub.1 -C.sub.8 alkyl, --SR.sub.6, --N(R.sub.7).sub.2, or a group of formula --OR.sub.6 or --O(CH.sub.2).sub.m --Z, whereinR.sub.6 represents C.sub.1 -C.sub.4 alkyl, C.sub.2 -C.sub.4 alkenyl, C.sub.3 -C.sub.10 cycloalkyl optionally substituted with C.sub.1 -C.sub.4 alkyl, C.sub.2 -C.sub.5 fluoroalkyl, phenyl optionally substituted with C.sub.1 -C.sub.4 alkyl or benzyl optionally substituted with C.sub.1 -C.sub.4 alkyl,R.sub.7 represents hydrogen or C.sub.1 -C.sub.5 alkyl,Z represents a group of formula --O(CH.sub.2).sub.q --R.sub.9 whereinq denotes an integer of 1 to 3, and R.sub.

Abstract: The projection screen includes a plurality of optical unit cells arranged together to form a display surface of the screen. The optical units cells that are constituents of the projection screen each include an elongated body portion formed of a light transmissive, preferably transparent material. One end of the body portion is formed as a convex lens surface, and an opposite end is formed with a spherical surface contour, preferably a concave surface contour. A light diffusing material is provided at the axial portion of the convex lens surface and a light reflecting material is provided at the axial portion of the spherical concave surface, with the light reflecting material having a reflecting surface directed toward the convex lens surface.