Abstract: A monochromatic-light reproduction type hologram having a hologram recorded area provided with interference fringes that form a hologram image, the hologram image being reproducible by irradiating the hologram recorded area with monochromatic light at a given angle. A plurality of hologram images different from each other in the directionality of interference fringes are multiple-recorded in the hologram recorded area. Alternatively, the hologram recorded area is divided into a plurality of regions so that a plurality of hologram images different from each other in the directionality of interference fringes are separately recorded in the divided regions. The recorded area is successively or simultaneously irradiated with monochromatic light rays at given angles corresponding to the directionality of interference fringes of the respective hologram images, to reproduce the hologram images as a plurality of information patterns or a single information pattern.

Abstract: An identification mark comprises a set of a plurality of mark elements. One mark element is divided into a large number of first and second fine square regions alternately arranged. One or two basic gratings selected from a plurality of types of basic gratings is/are drawn in both fine square regions, so that patterns are formed. Since the basic gratings are different in direction of the grating or spatial frequency, the types of the basic gratings are different from each other. One selected type of basic gratings is drawn in all first fine square regions. Similarly, the one or another type of basic gratings is drawn in all second fine square regions. At least one first fine region and at least one second fine region exist in the diameter of the light beam when light is radiated on the mark element for optical read. Thereby, types of patterns, which one mark element can obtain, are increased.