Abstract: A planar light source includes a substrate, light sources, and at least one partitioning member. The partitioning member includes first wall parts, second wall parts, and partitioned regions. The first wall parts define first ridges extending in a first direction. The second wall parts define second ridges extending in a second direction. The partitioned regions each is surrounded by the first ridges and the second ridges in a plan view. the partitioned regions are arranged in the first and second directions. At least one first cut is defined on at least one of the first ridges. At least one second cut is defined on at least one of the second ridges. The at least one first cut and the at least one second cut are spaced apart from each other. At least one of the light sources is arranged in a corresponding one of the partitioned regions.

Abstract: Purified .alpha.-amino-.epsilon.-caprolactam free from not only visible ray-absorbing substances but ultra-violet ray-absorbing substances, such as, tetrahydrophenazine and octahydrophenazine, and volatile basic substances such as, ammonium salts, is obtained by dissolving a crude .alpha.-amino-.epsilon.-caprolactam in a solvent consisting of at least one alkyl ester of saturated aliphatic acid of the formula:C.sub.m H.sub.2m+1 COOC.sub.n H.sub.2n+1wherein m is 1 or 2 and n is 1, 2, 3 or 4, at an elevated temperature at which the crude material can be completely dissolved in the solvent, cooling the solution to a lowered temperature at which the .alpha.-amino-.epsilon.caprolactam is allowed to recrystallize from the solution, and separating the crystals of the purified .alpha.-amino-undecanoic acid from the solution.