A light-emitting element is mounted in a cup-like portion formed on a substrate and a case. The optical connector includes a latch provided in a cantilever form on an external surface of the optical connector and deformable for attachmentdetachment with respect to an adaptor, and an excessive deformation preventing unit that prevents excessive deformation of the latch. Playback of any desired segment may be effected during recording or at any time afterward; and playback does not interfere with the recording of realtime information. As-formed arrays can be combined with other materials to form a composite 3-D structure. A plurality of subarrays of patterns then are generated, each subarray corresponding to a surface treatment product type. The polymer adhesive is preferably a froth liquid polyurethane foam.