Optical information reading apparatus

• US 20060054844A1
• Filed: 08/23/2005
• Published: 03/16/2006
• Est. Priority Date: 08/25/2004
• Status: Active Grant

• Current Assignee: DENSO Corporation, Denso Wave Inc (DENSO Corporation)
• Original Assignee: DENSO Corporation
• Inventors: Itou, Kunihiko
• Granted Patent: US 7,279,696 B2
• Time in Patent Office: Days
• US Class Current: 250/566
• CPC Class Codes: G06K 2207/1011 Aiming
• CPC Class Codes: G06K 7/10702 Particularities of propagating elements, e.g. lenses, mirrors G06K7/10831 takes precedence
• CPC Class Codes: G06K 7/10851 Circuits for pulse shaping, amplifying, eliminating noise signals, checking the function of the sensing device basic electronic circuitry H03
• CPC Class Codes: G06K 7/10881 constructional details of hand-held scanners

Abstract

In an optical information reading apparatus, a marker beam irradiating unit has a light beam source for emitting a light beam, a diffusing lens for diffusing the light beam emitted from the light beam source, and a collective lens for collecting the light beam diffused by the diffusing means. The marker beam irradiating unit has a pattern forming unit for forming a marker beam based on the light beam collected by the collecting means to irradiate the marker beam. The marker beam has a predetermined beam pattern indicating the reading position of the pickup unit.

Claims

1. An optical information reading apparatus comprising:

a pickup unit having a predetermined reading position and configured to optically pickup information of a target when the information is located at the reading position; and

a marker beam irradiating unit comprising;

a light beam source configured to emit a light beam;

a beam pattern forming member arranged at a light beam emitting side of the light beam source;

a diffusing lens coaxially arranged between the light beam source and the beam pattern forming member and configured to diffuse the light beam emitted from the light beam source; and

a collective lens coaxially arranged between the diffusing lens and the beam pattern forming member and configured to collect the diffused light beam so that the collected light beam is incident into the beam pattern forming member, the beam pattern forming member being configured to form a marker beam based on the incident collected light beam to irradiate the marker beam, the marker beam having a predetermined beam pattern indicating the reading position of the pickup unit.

2. An optical information reading apparatus according to claim 1, wherein the light beam emitted from the light beam source has a substantially prolate ellipsoid profile in a first direction orthogonal to an optical axis of the light beam source, and the diffusing lens has an output surface facing the collective lens, the output surface being concavely curved in a second direction orthogonal to the optical axis and the first direction, the output surface allowing the light beam emitted from the light beam source incident into the diffusing lens to be diffused in the second direction so that the diffused laser beam by the diffusing lens has a substantially circle in a lateral cross section thereof.

3. An optical information reading apparatus according to claim 2, wherein the read position is a predetermined area corresponding to a field of view of the pickup unit, and the collective lens is configured to collect the diffused light beam by the diffusing lens so that the collected light beam is incident into the pattern forming member with the beam profile thereof being kept in a circle in the lateral cross section, the circular shaped profile of the light beam incident into the pattern forming member corresponding to the predetermined area.

4. An optical information reading apparatus according to claim 1, wherein the pattern forming member includes a slit plate through which at least one slit is formed, the slit plate being arranged to allow the collected light beam to be incident into the at least one slit, a shape of the at least one slit corresponding to the predetermined beam pattern, the at least one slit being arranged in the slit plate so as to correspond to an arrangement of the beam pattern.

5. An optical information reading apparatus according to claim 1, wherein the pattern forming member includes a beam pattern forming lens with at least one lens element, the beam pattern forming lens being arranged to allow the collected light beam to be incident into the at least one lens element, the at least one lens element having a substantially cylindrical refractive surface and arranged to correspond to the beam pattern.

6. An optical information reading apparatus according to claim 5, a radius of curvature at each position on the refractive surface of the at least one lens element being changed depending on a distance between each position on the refractive surface and a position of the light beam source from which the light beam is emitted.

7. An optical information reading apparatus according to claim 1, wherein the pattern forming member includes a diffraction grating with a hologram plane, the hologram plane being formed with a diffraction pattern corresponding to the predetermined beam pattern, the diffraction grating being arranged to allow the collected light beam to be incident into the grating pattern of the hologram plane thereof.

8. An optical information reading apparatus according to claim 2, wherein the pickup unit comprises an area sensor with a predetermined aspect ratio, and a ratio of length of the circular profile of the diffused laser beam by the diffusing lens in the first direction to length of the circular profile of the diffused laser beam in the second direction is substantially equal to the aspect ratio, the first and second directions corresponding to horizontal and vertical directions of the area sensor, respectively.

9. An optical information reading apparatus according to claim 1, wherein the light beam source includes a laser diode configured to emit a laser beam as the light beam.