초록 ▼

A portable terminal unit of tablet configuration contains an optical reader for scanning two-dimensional information on a target area. The terminal unit has an optical window near an underside thereof and contains an optical reader having a given depth of field and field of view at a given range fro

A portable terminal unit of tablet configuration contains an optical reader for scanning two-dimensional information on a target area. The terminal unit has an optical window near an underside thereof and contains an optical reader having a given depth of field and field of view at a given range from the window. The apparatus includes a ranger for operably determining the range of the target area from the terminal unit and a controller for operably controling activation of the reader. The controller may be configured to permit activation of the reader as: the target area is spaced within a certain tolerance range about an optimal focal length from the reader; the target area is spaced within the depth of field of the reader and motion of the terminal unit relative to the target area is halted; or the target area is spaced within the depth of field of the reader and motion of the terminal unit relative to the target area is reversed.

대표청구항 ▼

[ I claim as my invention:] [5.] A method for imaging optical indicia contained on a target surface, comprising the steps of:a) determining an optimal focus location for an optical reader having a known depth of field and an optimal focus length;b) determining the distance to the target surface;c) d

[ I claim as my invention:] [5.] A method for imaging optical indicia contained on a target surface, comprising the steps of:a) determining an optimal focus location for an optical reader having a known depth of field and an optimal focus length;b) determining the distance to the target surface;c) determining whether the distance to the target surface is changing; andd) permitting activation of the optical reader, to capture an image of the target surface, if it is determined that a target surface is moving away from the optimal focus location and that the target surface is within the optical reader's depth of field.