Abstract: A light guide (3) for a surface light source used to constitute a surface light source in combination with a primary light source (1) and guiding light emitted from the primary light source (1). The light guide (3) has a light incident end face (31) on which the light emitted from the primary light source (1) impinges, a light exit face (33) from which guided light exits, and a rear surface (34) on the opposite side. A plurality of prism arrays (34a) extending in a direction traversing the light incident end face (31) are formed on at least one of the light exit face (33) and the rear surface (34), and each prism array (34a) has a plurality of divided top portions (34a1, 34a2) where the top is divided in the cross-section profile thereof in at least a partial region in the extending direction.

Abstract: A light guide (3) for a surface light source used to constitute a surface light source in combination with a primary light source (1) and guiding light emitted from the primary light source (1). The light guide (3) has a light incident end face (31) on which the light emitted from the primary light source (1) impinges, a light exit face (33) from which guided light exits, and a rear surface (34) on the opposite side. A plurality of prism arrays (34a) extending in a direction traversing the light incident end face (31) are formed on at least one of the light exit face (33) and the rear surface (34), and each prism array (34a) has a plurality of divided top portions (34a1, 34a2) where the top is divided in the cross-section profile thereof in at least a partial region in the extending direction.

Abstract: A planar light source device capable of preventing the occurrence of a luminescent line in the vicinity of a light incident end face without interrupting an incident light incoming from a primary light source and entering at a light incident end face, and being not likely to cause a decrease in incident light quantity, that is, without lowering entire luminance and producing dark lines to be caused when light to be originally guided is shaded. A platy light guide (3) that guides light emitted from a primary light source (1) and has a light incident end face (31) for receiving light from the primary light source (1) and a light emitting face (33) for outputting the guided light which is formed with a light absorption zone (36) extending along the light incident end face (31) and having a width of 50 to 1000 ?m, and a side edge closer to the light incident end face (31) of the light absorption zone (36) is up to 300 ?m away from the light incident end face (31).

Abstract: An amino acid compound of the formula: ##STR1## wherein R is a lower alkyl group, R.sub.1 is a hydrogen atom or a protecting group for carboxyl, R.sub.2 is a hydrogen atom, a protecting group for amino, an optionally substituted allyl group of the formula: ##STR2## (wherein R.sub.3 and R.sub.4 are each a hydrogen atom, a lower alkyl group or an aryl group), a beta-hydroxyethyl group in which the hydroxyl group is optionally protected, a formylmethyl group in which the formyl group is optionally protected, a carboxymethyl group in which the carboxyl group is protected or a 2-furylmethyl group and X is an optionally protected carboxyl group, a hydroxymethyl group in which the hydroxyl group is optionally protected or a substituted mercaptomethyl group of the formula:--CH.sub.2 SR.sub.5(wherein R.sub.5 is an aryl group or an ar(lower)alkyl group), which is a useful intermediate in the synthesis of 1-alkylcarbapenem compounds.