Patent ID: 8561904
Filing Date: 2013-10-22
Classification: G06K

Abstract:
1. An optical apparatus that, upon imaging a target pattern that comprises characters, numeric values, numbers, or an arrangement of these and carries predetermined information, by means of an imaging apparatus, projects on a pattern forming plane where the target pattern is formed a guide pattern that is projected to show a normal shape appearance on the pattern forming plane only when the imaging apparatus is in a focused state with respect to the pattern forming plane, as a light projection pattern for determining a location of the imaging apparatus in an optical axis direction with respect to the pattern forming plane, the optical apparatus comprising: one light source that outputs light; a collimation lens that collimates the light output from the light source; a diffractive optical element that divides the light collimated through the collimation lens into a plurality of first light beams to travel in varying directions; and a computer-generated hologram that divides the plurality of first light beams each into a plurality of second light beams, and outputs these plurality of second light beams of each first light beam in varying directions such that the second light beams of each first light beam are projected on the pattern forming plane in a state said second beams of each first light beam overlap the second beams of another first light beam only in the focused state, wherein: the second light beams of each first light beam are formed to show a predetermined shape to match the guide pattern after being output from the computer-generated hologram; and the guide pattern is formed when the second light beams of each first light beam are projected on the pattern forming plane.