Multiple window scanner and method for multiple focal distance reading

• US 5,869,827 A
• Filed: 08/15/1997
• Issued: 02/09/1999
• Est. Priority Date: 09/24/1991
• Status: Expired due to Fees

• Current Assignee: PSC Scanning, Inc. (Datalogic ADC Incorporated)
• Original Assignee: Spectra-Physics Scanning Systems, Inc.
• Inventors: Rando, Joseph F.
• Primary Examiner(s): Gross, Anita Pellman
• Assistant Examiner(s): LEE, MICHAEL GUNYOUNG
• Application Number:
  US08/912,891
• Time in Patent Office: 543 Days
• Field of Search: 235/467, 235/462, 235/383, 235/375, 235/454
• US Class Current: 235/462.4
• CPC Class Codes: A47F 9/046 Arrangement of recording means in or on check-out counters record carriers or readers per se G06K
• CPC Class Codes: A47F 9/047 for recording self-service articles without cashier or assistant
• CPC Class Codes: G06K 13/00 Conveying record carriers from one station to another, e.g. from stack to punching mechanism conveying record carriers combined with another operation, e.g. with reading G06K17/00
• CPC Class Codes: G06K 7/10693 for omnidirectional scanning
• CPC Class Codes: G06K 7/10811 Focalisation
• CPC Class Codes: G06K 7/1096 the scanner having more than one scanning window, e.g. two substantially orthogonally placed scanning windows for integration into a check-out counter of a super-market
• CPC Class Codes: G07G 1/0045 with a code reader for reading of an identifying code of the article to be registered, e.g. barcode reader or radio-frequency identity [RFID] reader

Abstract

A multiple window data reading device and method for reading symbols such as bar codes through each window, data reading being focused to different focal distances in the scan volume with sensors provided to control focal distance setting from each of the windows.

Claims

1. A bar code scanning system comprising

a housing having a first window and a second window arranged generally orthogonally to one another facing first and second sides of a scan volume;

a first set of pattern mirrors positioned adjacent the first window;

a second set of pattern mirrors positioned adjacent the second window;

a first laser source and a second laser source within the housing;

a single scanning mechanism within the housing comprising a mirror polygon for scanning light from the first laser source in a scan pattern out through the first window and for scanning light from the second laser source in a scan pattern out the second window, wherein said mirror polygon reflects the light from the first laser source across the first set of pattern mirrors and out the first window and reflects the light from the second laser source across the second set of pattern mirrors and out the second window;

a first sensor for sensing distance to an object in the scan volume from the first window;

a second sensor for sensing distance to the object in the scan volume from the second window.

2. A bar code scanning system according to claim 1 further comprising a beam splitter which divides laser beam produced by the first laser source into a first beam portion and a second beam portion, the first beam portion being directed to a first side of the mirror polygon by which the first beam portion is scanned across the first set of pattern mirrors forming the first group of scanning beams which are reflected out the first window, the second beam portion being directed to a second side of the mirror polygon by which the second beam portion is scanned across the second set of pattern mirrors forming the second group of scanning beams which are reflected out the second window.

3. A bar code scanning system according to claim 1 further comprising means for adjusting focal distance for the light from the first laser source based upon the distance to the object sensed by the first sensor;

means for adjusting focal distance for the light from the second laser source based upon the distance to the object sensed by the second sensor.

4. A bar code scanning system according to claim 1 wherein the first sensor comprises a measuring light beam and a detector, the measuring light beam determining whether height of an object in the scan volume is greater or less than a predetermined height.

5. A bar code scanning system according to claim 1 wherein the first light source comprises a first laser diode pair comprising first and second laser diodes focused at different focal distances.

6. A bar code scanning system according to claim 5 wherein the first sensor deactivates the first laser diode and activates the second laser diode depending upon conditions sensed by the first sensor.

7. A bar code scanning system according to claim 1 wherein the first light source comprises a laser diode producing a laser beam and a beam splitter for splitting the laser beam into first and second reading beams.

8. A data reading system comprising

a housing having a first window and a second window arranged to face different sides of a scan volume;

a first set of pattern mirrors positioned adjacent the first window;

a second set of pattern mirrors positioned adjacent the second window;

a first laser diode pair comprising first and second laser diodes and a second laser diode pair comprising third and fourth laser diodes within the housing;

a first sensor for sensing position of an object in the scan volume from the first window;

a second sensor for sensing position of the object in the scan volume from the second window;

a scanning mechanism within the housing for scanning light from the first laser diode pair in a scan pattern out through the first window and for scanning light from the second laser diodes in a scan pattern out the second window, wherein said scanning mechanism reflects the light from the first and second laser diodes across the first set of pattern mirrors and out the first window and reflects the light from the second laser source across the second set of pattern mirrors and out the second window,

wherein the first and second laser diodes are focused at different focal positions within the scan volume and wherein the third and fourth laser diodes are focused at different focal positions within the scan volume.

9. A data reading system according to claim 8 further comprising

means for selecting one of the first laser diode and the second laser diode to adjust focal distance for light from the first laser diode pair based upon the position of the object as sensed by the first sensor;

means for selecting one of the third laser diode and the fourth laser diode to adjust focal distance for light from the second laser diode pair based upon the position of the object as sensed by the second sensor.

10. A method for scanning an item being passed through a scan volume, comprising the steps of

producing a first set of scanning beams and passing the first set of scanning beams through a first window and into the scan volume;

producing a second set of scanning beams and passing the second set of scanning beams through a second window and into the scan volume;

determining distance from the first window to the item and determining distance from the second window to the item;

adjusting focal distance of the first set of scanning beams based upon the distance determined from the first window and separately adjusting focal distance of the second set of scanning beams based upon the distance determined from the second window.

11. A method according to claim 10 further comprising the step of adjusting beam power of the first set of scanning beams.

12. A method according to claim 10 further comprising the step of adjusting spot size of the first set of scanning beams.

13. A method according to claim 10 wherein the step of producing a first set of scanning beams comprises producing a first beam from a first laser diode and a second beam from a second laser diode and focusing the first and second beams at different waist distances and wherein the step of adjusting focal distance of the first set of scanning beams comprises activating the first laser diode and deactivating the second laser diode based upon the distance determined from the first window.

14. A method according to claim 10 further comprising

arranging the first window and the second window on different sides of the scan volume;

passing the item through the scan volume on a conveyor.

15. A method according to claim 14 further comprising reading through the conveyor.

16. A method according to claim 10 further comprising arranging the first window and the second window generally orthogonally to one another.

17. A method according to claim 10 wherein the step of determining distance from the first window to the item comprises determining height of the item.