Planar laser illumination module (PLIM) employing high-frequency modulation (HFM) of the laser drive currents and optical multplexing of the output laser beams

• US 7,784,695 B2
• Filed: 10/30/2007
• Issued: 08/31/2010
• Est. Priority Date: 11/24/2000
• Status: Expired due to Fees

• Current Assignee: Metrologic Instruments Incorporated (Honeywell International Inc.)
• Original Assignee: Metrologic Instruments Incorporated (Honeywell International Inc.)
• Inventors: Gardner, John A., Zhu, Xiaoxun, Veksland, Michael, Ren, Jie, Knowles, C. Harry, Xian, Tao, Liu, Yong, Good, Timothy, Giordano, Patrick, Schmidt, Mark, Kotlarsky, Anatoly, Tao, Xi, Liu, JiBin, Essinger, Steven, Kearney, Sean, Ellis, Duane, Ciarlante, Nicholas, Hernandez, Mark, Zhuo, Ming, Furlong, John A.
• Primary Examiner(s): Kim; Ahshik
• Application Number:
  US11/980,083
• Publication Number:
  US 20080135622A1
• Time in Patent Office: 1,036 Days
• Field of Search: 235/454, 235/462.42, 235/462.01, 235/462.09, 235/462.32
• US Class Current: 235/454
• 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: G02B 27/48 Laser speckle optics
• CPC Class Codes: G06K 2207/1012 Special detection of object
• CPC Class Codes: G06K 7/10544 by scanning of the records by radiation in the optical part of the electromagnetic spectrum
• CPC Class Codes: G06K 7/10564 Light sources
• CPC Class Codes: G06K 7/10574 Multiple sources
• CPC Class Codes: G06K 7/10613 by rotation, e.g. polygon
• CPC Class Codes: G06K 7/10623 Constructional details
• CPC Class Codes: G06K 7/10693 for omnidirectional scanning
• CPC Class Codes: G06K 7/10712 Fixed beam scanning
• CPC Class Codes: G06K 7/10722 Photodetector array or CCD scanning
• CPC Class Codes: G06K 7/10732 Light sources
• CPC Class Codes: G06K 7/10782 Slot readers
• CPC Class Codes: G06K 7/10792 Special measures in relation to the object to be scanned
• 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 7/10861 sensing of data fields affixed to objects or articles, e.g. coded labels postal sorting B07C3/14, conveying articles B65G47/48
• CPC Class Codes: G06Q 20/208 Input by product or record sensing, e.g. weighing or scanner processing
• CPC Class Codes: G06Q 30/06 Buying, selling or leasing transactions
• CPC Class Codes: G06V 10/141 Control of illumination
• CPC Class Codes: G07G 1/0036 Checkout procedures
• 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
• CPC Class Codes: G07G 3/00 : Alarm indicators, e.g. bells
• CPC Class Codes: G07G 3/006 : False operation

Abstract

A planar laser illumination module (PLIM) including: (i) a laser illumination source driven preferably by high frequency modulated (HFM) diode current drive circuitry; (ii) a beam collimating optics disposed beyond the laser illumination source; (ii) an optical beam multiplexer (OMUX) device disposed beyond the collimating optics; and (iv) a planarizing-type illumination lens array disposed beyond the OMUX device, and arranged for generating a plurality of substantially planar coherence-reduced laser illumination beams (PLIBs) that form a composite substantially planar laser illumination beam (PLIB) having substantially reduced spatial/temporal coherence.

Claims

1. A planar laser illumination module (PLIM) comprising:

(i) a laser illumination source driven by high frequency modulated (HFM) diode current drive circuitry, for producing a laser beam having a characteristic wavelength, a coherence length, and spectral sideband components about said characteristic wavelength;

(ii) beam collimating optics disposed beyond said laser illumination source, for producing an input laser beam;

(ii) an optical beam multiplexer (OMUX) device disposed beyond said beam collimating optics, for multiplexing said input laser beam and producing multiple spatial-coherence reduced output laser beams; and

(iv) a planarizing-type illumination lens array disposed beyond said OMUX device, and arranged for receiving said multiple spatial-coherence reduced output laser beams and generating a plurality of substantially planar coherence-reduced laser illumination beams that form a composite substantially planar laser illumination beam having a substantially reduced coherence length.

3. The planar laser illumination module of claim 1, wherein said laser illumination source is selected from the group consisting of a visible laser diode (VLD) and an IR laser diode (IRLD).

7. The planar laser illumination module of claim 1, wherein said OMUX device comprises a single glass plate bearing reflective and semi- reflective coatings to optically multiplex said input laser beam into said multiple spatial- coherence reduced output laser beams;

and wherein said multiple spatial-coherence reduced output laser beams are planarized into said plurality of substantially planar coherence-reduced laser illumination beams by way of said planarizing-type illumination lens array being disposed in close proximity with said OMUX device.

2. A digital illumination and imaging system comprising:

a planar laser illumination module (PLIM) including;

(i) a laser illumination source driven by high frequency modulated (HFM) diode current drive circuitry, for producing a laser beam having a characteristic wavelength, a coherence length, and spectral sideband components about said characteristic wavelength;

(ii) a beam collimating optics disposed beyond said laser illumination source, for producing an input laser beam;

(ii) an optical beam multiplexer (OMUX) device disposed beyond said beam collimating optics, for multiplexing said input laser beam and producing multiple spatial-coherence reduced output laser beams; and

(iv) a planarizing-type illumination lens array disposed beyond said OMUX device, and arranged for receiving said multiple spatial-coherence reduced output laser beams and generating a plurality of substantially planar coherence-reduced laser illumination beams that form a composite substantially planar laser illumination beam having a substantially reduced coherence length; and

a digital image detection array for detecting digital images of an object illuminated by said composite substantially planar laser illumination beam;

wherein the power of speckle pattern noise observed in a digital image of an object detected at said digital image detection array is substantially reduced when said digital image is formed using said composite substantially planar laser illumination beam.

8. The digital illumination and imaging system of claim 2, wherein said OMUX device comprises a single glass plate bearing reflective and semi-reflective coatings to optically multiplex said input laser beam into said multiple spatial-coherence reduced output laser beams;

and wherein said multiple spatial-coherence reduced output laser beams are planarized into said plurality of substantially planar coherence-reduced laser illumination beams by way of said planarizing-type illumination lens array being disposed in close proximity with said OMUX device.

4. An illumination system, comprising:

a planar laser illumination module (PLIM) including;

(i) a laser illumination source driven by high frequency modulated (HFM) current drive circuitry, for producing a laser beam having a characteristic wavelength, a coherence length, and spectral sideband components about said characteristic wavelength;

(ii) beam collimating optics disposed beyond said laser illumination source, for producing an input laser beam;

(ii) an optical beam multiplexer (OMUX) device disposed beyond said beam collimating optics, for multiplexing said input laser beam and producing multiple spatial-coherence reduced output laser beams; and

(iv) a planarizing-type illumination lens array disposed beyond said OMUX device, and arranged for receiving said multiple spatial-coherence reduced output laser beams and generating a plurality of substantially planar coherence-reduced laser illumination beams that form a composite substantially planar laser illumination beam having a substantially reduced coherence length;

wherein said laser illumination source is mounted in a support block, and said HFM diode current drive circuitry further includes a flexible HFM circuit connected to a laser diode current drive circuit.

5. The illumination system of claim 4, wherein said laser diode current drive circuit is electrically interfaced to a printed circuit (PC) board.

6. The illumination system of claim 4, wherein said OMUX device comprises a single glass plate bearing reflective and semi-reflective coatings to optically multiplex said input laser beam into said multiple spatial-coherence reduced output laser beams;

and wherein said multiple spatial-coherence reduced output laser beams are planarized into said composite plurality of substantially planar coherence-reduced laser illumination beams by way of said planarizing-type illumination lens array being disposed in close proximity with said OMUX device.