Omni-directional optical code reader using scheimpflug optics

• US 6,621,063 B2
• Filed: 06/21/2001
• Issued: 09/16/2003
• Est. Priority Date: 06/21/2001
• Status: Expired due to Term

• Current Assignee: PSC Scanning, Inc. (Datalogic ADC Incorporated)
• Original Assignee: PSC Scanning, Inc. (Datalogic ADC Incorporated)
• Inventors: McQueen, Alexander M
• Primary Examiner(s): Allen, Stephone
• Assistant Examiner(s): Glass, Christopher W
• Application Number:
  US09/884,975
• Publication Number:
  US 20020195550A1
• Time in Patent Office: 817 Days
• Field of Search: 250/566, 250/568, 250/234, 250/235, 250/236, 250/208.1, 235/462.09, 235/462.1, 235/462.11, 235/462.24, 235/462.41, 235/462.42, 235/462.01
• US Class Current: 250/208.1
• CPC Class Codes: G06K 2007/10485 Arrangement of optical elements
• CPC Class Codes: G06K 7/10722 Photodetector array or CCD scanning

Abstract

An optical code reader for reading optical codes in any orientation with a preferred depth of field (DOF), the optical code reader including imaging sensor arrays arranged at angles to one another and tilted in accordance with the Scheimpflug principle to allow for omni-directional reading and a preferred DOF. In addition, an optical code reader may also include an optical device to rotate an image as it is projected upon a stationary tilted image sensor array. Still further, an optical code reader may include a rotating imaging sensor array tilted in accordance with the Scheimpflug principle to allow for omni-directional reading with a preferred DOF.

Claims

1. An omni-directional optical code reader comprising:

a lens system;

a first image sensor array for detecting a signal representative of light reflected from an optical code through said lens system, wherein the first image sensor array is disposed approximately at a tilt angle α

with respect to the lens system;

a second image sensor array for detecting a signal representative of light reflected from an optical code through said lens system, wherein the second image sensor array is disposed approximately at the tilt angle α

with respect to the lens system and oriented in a direction substantially orthogonal to said first image sensor array; and

a first beam splitter to provide a reflected image of the optical code to the first image sensor array and a transmissive image of the optical code to the second image sensor array.

2. An omni-directional optical code reader comprising:

a lens system;

N image sensor arrays for detecting a signal representative of light reflected from an optical code through said lens system, wherein each of said N image sensor arrays is disposed at approximately the same tilt angle α

with respect to the lens system, each of said N image sensor arrays oriented in a direction approximately 180/N degrees in relation to one another, N being an integer greater than 1.

3. An omni-directional optical code reader comprising:

a lens system having an optical axis;

an image sensor array for generating a pattern of analog signal lines representative of light reflected from an optical code through said lens system, wherein the image sensor array is disposed at a tilt angle α

with respect to the lens system and wherein the image sensor array is rotatable about the optical axis while maintaining the tilt angle α

to produce an omni-directional sample-scan line pattern.

4. The omni-directional optical code reader of claim 3, wherein rotation of the image sensor array is synchronized with a timing cycle of raster scan line reading of the image sensor array.

5. An omni-directional optical code reader comprising:

a lens system;

an image sensor array for detecting a signal representative of light reflected from an optical code through said lens system, wherein the image sensor array is disposed at a tilt angle α

with respect to the lens system; and

an optical device for rotating the image of the optical code.

6. The omni-directional optical code reader of claim 5, wherein rotation of the image of the optical code is synchronized with a timing cycle of raster scan line reading of the I-mage sensor array.

7. The omni-directional optical code reader of claim 5 wherein the optical device is a dove prism.

8. The omni-directional optical code reader of claim 5, wherein the optical device is a mirror assembly.

9. An omni-directional optical code reader comprising:

a first lens system;

a first image sensor array for detecting a signal representative of light reflected from an optical code through said first lens system, wherein the first image sensor array is disposed approximately at a tilt angle α

with respect to the first lens system;

a second lens system;

a second image sensor array for detecting a signal representative of light reflected from an optical code through said second lens system, wherein the second image sensor array is disposed approximately at the tilt angle with respect to the second lens system and oriented in a direction substantially orthogonal to said first image sensor array; and

a beam splitter to provide a reflected image of the optical code to the first lens system and image sensor array and a transmissive image of the optical code to the second lens system and image sensor array.

10. A method of optical reading comprising the steps of

focusing an image with a lens system along an optical axis toward an image sensor array;

arranging the image sensor array at a tilt angle α

with respect to the lens system according to Scheimpflug principle;

rotating the image sensor array about the optical axis while maintaining the tilt angle α

;

generating a pattern of analog signal lines representative of light reflected from an object being read through said lens system.

11. A method according to claim 10 wherein the image sensor array comprises a two-dimensional array.

12. A method according to claim 11 further comprising

rotating the image sensor array in synchronicity with timing of raster scan line reading of the image sensor array.

13. A method according to claim 10 further comprising

synchronizing rotational speed of the image sensor array with time between successive imaging cycles of the image sensor array.

14. A method of optical reading comprising the steps of

receiving an image from an object to be read;

directing the image so as to direct the image toward a first lens system and to direct the image toward a second lens system;

focusing the image with the first lens system onto a first sensor array, the first sensor array being arranged at a tilt angle with respect to the first lens system according to Scheimpflug principle;

focusing the image with the second lens system onto a second sensor array, the second sensor array being arranged at a tilt angle with respect to the second lens system according to Scheimpflug principle.

15. A method according to claim 14 wherein the step of directing the image comprises splitting the image for simultaneously directing the image toward the first lens system and the second lens system.

16. A method according to claim 15 wherein the step of splitting the image comprises splitting the image via a beam splitter.

17. A method according to claim 14 further comprising arranging an image plane of the first sensor array orthogonal to an image plane of the seocond sensor array.