Optical pattern reading apparatus with movable optical unit

Abstract

An optical reading apparatus for moving a mirror in a back and forth motion such that the mirror scans the light reflected from an optical pattern and sequentially projects narrow segments of the reflected image onto a linear image sensor. Moving the mirror includes means for mounting the mirror within a movable case which is mounted on a shaft to selectively cause the case to go back and forth in a seesaw-like fashion. As the case goes back and forth, it causes the mirror to sweep or scan across the reflected image of an optical pattern. As the mirror sweeps across the reflected image of the optical pattern it sequentially projects different segments of the optical pattern onto the linear image sensor until the entire optical pattern is projected onto the linear image sensor. The linear image sensor is operable at a high rate of speed and is sufficiently sensitive that it can sense numerous (e.g., 50, or more) segments of the reflected image during one sweep of the mirror. The image sensor may be a solid state device having a large number of photosensitive elements formed along a row. In a preferred embodiment, the light for illuminating the optical pattern to be read is also mounted within the movable case so as to move with the case, whereby projected light is swept across the optical pattern as it is being read, with greater illumination being provided for those segments whose reflected light is being projected on the image sensor.