SCANNING SYSTEM

• US 20140319219A1
• Filed: 04/26/2013
• Published: 10/30/2014
• Est. Priority Date: 04/26/2013
• Status: Active Grant

• Current Assignee: Datalogic Automation Incorporated (Datalogic S.p.A.)
• Original Assignee: Datalogic Automation Incorporated (Datalogic S.p.A.)
• Inventors: Liu, Xinping, Chaleff, Edward I.
• Granted Patent: US 9,373,017 B2
• Time in Patent Office: Days
• US Class Current: 235/455
• CPC Class Codes: G06K 7/10702 Particularities of propagating elements, e.g. lenses, mirrors G06K7/10831 takes precedence
• CPC Class Codes: G06K 7/10792 Special measures in relation to the object to be scanned
• CPC Class Codes: G06K 7/10831 Arrangement of optical elements, e.g. lenses, mirrors, prisms optical elements per se G02B

Abstract

A scanning system has a collimated light source and a movable reflective surface. The surface receives light from the light source, reflects the received light to a target surface, receives light reflected from the target surface, and reflects this light to a detector. An aperture disposed between the reflective surface and the target surface has a non-transmissive portion with a width in a direction perpendicular to the laser scan direction that varies over the scan direction.

Claims

1. A scanning tunnel comprising:

a frame;

a conveyor structure having a generally planar surface and being moveable with respect to the frame in a direction of travel; and

a scanning system in a position with respect to the frame that is fixed during movement of the conveyor structure in the direction of travel, wherein the scanning system comprises

a laser light source,

a rotatable, multi-faceted wheel disposed with respect to the laser light source and the conveyor structure so that when the wheel rotates, and a facet receives light from the laser light source, the facet

reflects the light to the conveyor structure in a scan across the conveyor structure in a direction transverse to the direction of travel,

receives light reflected from the conveyor structure and objects carried by the conveyor structure, and

reflects the reflected light to a detector, and

an aperture that is disposed between the wheel and the conveyor structure so that light from the laser light source that is reflected from the conveyor structure and the objects to the facet passes through the aperture, the aperture having

a first area that receives and transmits to the facet light from the laser light source that is reflected from the conveyor structure and the objects, and

a second area that receives and blocks or diffuses light from the laser light source that is reflected from the conveyor structure and the objects,

wherein the second area has a total width in a direction perpendicular to the transverse direction that varies over the transverse direction.

4. The scanning system as in claim 1, wherein the aperture is disposed between the wheel and the conveyor structure so that light from the laser light source that is reflected from the wheel to the conveyor structure passes through the aperture, and wherein the aperture defines a portion of the first area at which the aperture receives the light reflected from the wheel so that the scan traverses at least a predetermined width of the conveyor structure.

5. The scanning tunnel as in claim 4, wherein the aperture defines respective portions of the second area on opposite sides of the portion of the first area, so that the scan traverses only the predetermined width of the conveyor structure.

6. The scanning tunnel as in claim 4, wherein the second area comprises a first portion and a second portion, wherein the first portion has a width in the direction perpendicular to the transverse direction that does not vary over the transverse direction, and wherein the second portion has a width in the direction perpendicular to the transverse direction that varies over the transverse direction.

7. The scanning tunnel as in claim 6, wherein the first portion is adjacent the portion of the first area at which the aperture receives the light reflected from the wheel.

8. The scanning tunnel as in claim 1, wherein a rate at which the total width of the second area varies over the transverse direction on one side of a center of the second area is different than a rate at which the total width of the second area varies over the transverse direction on the other side of the center.

9. The scanning tunnel as in claim 4, wherein the first portion is disposed in the aperture so that the first portion blocks or diffuses light reflected from a center portion of the predetermined width of the conveyor structure.

10. The scanning tunnel as in claim 9, wherein the first portion has a length in the transverse direction so that the first portion does not block or diffuse light reflected from respective portions of the predetermined width of the conveyor structure on opposite ends of the center portion.

11. The scanning tunnel as in claim 1, wherein the detector defines a width over which the detector collects light reflected from the facet, and wherein the width is predetermined to exclude a portion of light reflected from the facet that is received by the facet from the conveyor structure within a predetermined distance from the facet.

2. A scanning system comprising:

a source of collimated light;

a reflective surface movably disposed with respect to the source of collimated light so that when the reflective surface moves, and receives light from the source of collimated light, the reflective surface

reflects the light toward a target surface in a scan across the target surface in a first direction,

receives light reflected from the target surface, and

reflects the reflected light to a detector; and

an aperture that is disposed between the reflective surface and the target surface so that light from the source of collimated light that is reflected from the target surface to the reflective surface passes through the aperture, the aperture having

a first area that receives and transmits to the reflective surface light from the collimated light source that is reflected from the target surface, and

a second area that receives and blocks or diffuses light from the source of collimated light that is reflected from the target surface,

wherein the second area has a total width in a second direction perpendicular to the first direction that varies over the first direction.

3. The scanning system as in claim 2, wherein the source of collimated light is a laser light source.

12. The scanning system as in claim 2, wherein the aperture is disposed between the reflective surface and the target surface so that light from the source of collimated light that is reflected from the reflective surface to the target surface passes through the aperture.

13. The scanning tunnel as in claim 12, wherein the second area comprises a first portion and a second portion, wherein the first portion has a width in the second direction that does not vary over the first direction, and wherein the second portion has a width in the second direction that varies over the first direction.

14. The scanning tunnel as in claim 13, wherein the first portion is adjacent a portion of the first area that receives the collimated light reflected from the reflective surface.

15. The scanning tunnel as in claim 2, wherein a rate at which the total width of the second area varies over the first direction on one side of a center of the second area is different than a rate at which the total width of the second area varies over the first direction on the other side of the center.

16. A scanning tunnel comprising:

a frame;

a conveyor structure having a generally planar surface and being moveable with respect to the frame in a direction of travel; and

a scanning system in a position with respect to the frame that is fixed during movement of the conveyor structure in the direction of travel, wherein the scanning system comprises

a laser light source,

a rotatable, multi-faceted wheel disposed with respect to the laser light source and the conveyor structure so that when the wheel rotates, and a facet receives light from the laser light source, the facet

reflects the light toward the conveyor structure in a scan across the conveyor structure in a direction transverse to the direction of travel,

receives light reflected from the conveyor structure and objects carried by the conveyor structure, and

reflects the reflected light to a detector, and

an aperture that is disposed between the wheel and the conveyor structure so that light reflected from the facet toward the conveyor structure, and light from the laser light source that is reflected from the conveyor structure and the objects to the facet passes through the aperture, the aperture having

a first area that receives and transmits to the facet light from the laser light source that is reflected from the conveyor structure and the objects, and

a second area that receives and blocks or diffuses light from the laser light source that is reflected from the conveyor structure and the objects,

wherein the second area has a total width in a direction perpendicular to the transverse direction that varies over the transverse direction, and

wherein a rate at which the total width of the second area varies over the transverse direction on one side of a center of the second area is different than a rate at which the total width of the second area varies over the transverse direction on the other side of the center.