Automatic countertop laser scanner with flickering laser scanner beam for improved visibility thereof during bar code symbol reading

• US 5,616,908 A
• Filed: 01/11/1996
• Issued: 04/01/1997
• Est. Priority Date: 09/17/1991
• Status: Expired due to Term

• Current Assignee: Metrologic Instruments Incorporated (Honeywell International Inc.)
• Original Assignee: Metrologic Instruments Incorporated (Honeywell International Inc.)
• Inventors: Rockstein, George B., Naylor, Charles A., Wilz, David M., Knowles, Carl H.
• Primary Examiner(s): SHEPPERD, JOHN W
• Application Number:
  US08/584,135
• Time in Patent Office: 446 Days
• Field of Search: 235/462, 235/472
• US Class Current: 235/462.08
• CPC Class Codes: G02B 26/106 having diffraction gratings as scanning elements, e.g. holographic scanners holographic optical elements G02B5/32, holography G03H
• CPC Class Codes: G06K 17/0022 arrangements or provisions for transferring data to distant stations, e.g. from a sensing device "transfer between computer elements G06F13/00 "; data-transmission H04L
• CPC Class Codes: G06K 2207/1012 Special detection of object
• CPC Class Codes: G06K 2207/1016 Motor control or optical moving unit control
• CPC Class Codes: G06K 2207/1017 Programmable
• CPC Class Codes: G06K 2207/1018 Source control
• CPC Class Codes: G06K 7/10 by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
• CPC Class Codes: G06K 7/10564 Light sources
• CPC Class Codes: G06K 7/10584 Source control
• CPC Class Codes: G06K 7/10594 Beam path
• CPC Class Codes: G06K 7/10603 Basic scanning using moving elements
• CPC Class Codes: G06K 7/10663 using hologram
• CPC Class Codes: G06K 7/10673 Parallel lines
• CPC Class Codes: G06K 7/10693 for omnidirectional scanning
• 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 7/10801 Multidistance reading
• CPC Class Codes: G06K 7/10811 Focalisation
• 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: G06K 7/10871 : randomly oriented data-fields, code-marks therefore, e.g. concentric circles-code
• CPC Class Codes: G06K 7/10881 : constructional details of hand-held scanners
• CPC Class Codes: G06K 7/10891 : the scanner to be worn on a finger or on a wrist
• CPC Class Codes: G06K 7/109 : adaptations to make the hand-held scanner useable as a fixed scanner
• CPC Class Codes: G06K 7/14 : using light without selection of wavelength, e.g. sensing reflected white light G06K7/10831 - G06K7/1097 take precedence
• CPC Class Codes: G06K 7/1443 : locating of the code in an image
• CPC Class Codes: G07F 9/002 : Vending machines being part of a centrally controlled network of vending machines

Abstract

Disclosed is a fully automatic bar code symbol reading system having an hand-supportable laser bar code reading device The system has a number of operative states including, an object detection state, bar code presence detection state and a bar code symbol decoding state. During bar code symbol presence detection state, the visible laser scanning beam produced from the hand-supportable device flickers at a rate which improves the visual conspicuousness of the laser scanning beam in the scan field. The flicker characteristics of the laser scanning beam makes it substantially easier for the user to visually align the laser scanning beam with the bar code symbol on the detected object. Consequently, reading bar code symbols is made substantially easier using the automatic laser bar code symbol reading device of the present invention.

Claims

1. An automatic bar code symbol reading system having an object detection mode of operation, a bar code symbol detection mode of operation, and a bar code symbol reading mode of operation, said automatic bar code symbol reading system, comprising;

a housing mountable relative to a countertop surface, and having a light transmission aperture through which visible light can exit and enter said housing;

object detection means disposed in said housing for automatically detecting an object located within a portion of a scan field defined external to said housing;

laser beam source in said housing for producing a visible laser beam within said housing;

laser beam directing means in said housing, for directing said visible laser beam through said light transmission aperture and into a scan field defined external to said housing;

scanning mechanism in said housing for scanning said visible laser beam across said scan field and a bar code symbol on said detected object, said scanned visible laser beam flickering in said scan field at a rate in the range from about 0.1 Hz to about 16 Hz so as to improve the visual conspicuousness of said visible laser beam in said scan field during said bar code symbol detection mode of operation;

light detection means in said housing, for detecting the intensity of laser light reflected off said bar code symbol as said visible laser beam is scanned across said scan field and said bar code symbol, and for automatically producing scan data indicative of the detected intensity of said reflected laser light;

scan data processing means for processing produced scan data so as to detect and decode said bar code symbol on said detected object, and upon detecting and decoding said bar code symbol on said detected object, automatically producing symbol character data representative of said decoded bar code symbol; and

control means for controlling the operation of said automatic bar code symbol reading system.

2. The automatic bar code symbol reading system of claim 1, wherein said bar code symbol has first and second envelope borders, and wherein said scan data processing means comprises

means for detecting said first and second envelope borders of said bar code symbol, and

means for decoding said detected bar code symbol.

3. The automatic bar code symbol reading system of claim 1, wherein said housing comprises a hand-supportable structure supported within a stand, and said hand-supportable structure has a head portion and a handle portion, and wherein said laser beam source, said laser beam directing means, said scanning mechanism, and said light detection means are disposed in said head portion.

4. A method of reading bar code symbols using an automatic laser scanning unit having an object detection mode of operation, a bar code detection mode of operation, and a bar code symbol reading mode of operation, said method comprising the steps;

(a) supporting said automatic laser scanning unit stationary relative to a countertop surface;

(b) bringing an object in a non-contacting relationship with said automatic laser scanning unit so that said object is located within a least a portion of a scan field defined external to said automatic laser scanning unit;

(c) during said object detection mode, automatically generating an activation signal in response to the detection of said object located in said scan field;

(d) in response to the generation of said activation signal during step (c) and automatically entering said bar code symbol detection mode of operation;

(1) automatically activating a laser beam source and an electrically driven scanning element in said automatic laser scanning unit so as to produce a visible laser beam which (i) is directed through a light transmission aperture in said automatic laser scanning unit and scanned across said scan field and a bar code symbol on said detected object, and (ii) flickers in said scan field at a rate in the range from about 0.1 Hz to about 16 Hz so as to improve during said bar code symbol detection mode, the visual conspicuousness of said visible laser beam in said scan field during said bar code detection mode of operation;

(2) automatically detecting at said automatic laser scanning unit, the intensity of laser light reflected off said bar code symbol on said detected object, and automatically producing scan data indicative of the detected intensity of said reflected laser light, and

(3) automatically processing produced scan data in order to detect said bar code symbol on said detected object;

(e) upon detecting said bar code symbol, automatically entering said bar code symbol reading mode of operation, and continuing to produce scan data indicative of the detected intensity of laser light reflected of said detected bar code symbol, and automatically processing produced scan data in order to decode said laser bar code symbol on said detected object, and

(f) upon decoding said detected bar code symbol, automatically producing symbol character data representative of said decoded bar code symbol.

5. The method of claim 4 wherein said bar code symbol has first and second envelope borders, and wherein substep (d)(3) comprises detecting said first and second envelope borders of said bar code symbol and decoding said detected bar code symbol.

6. An automatic bar code symbol reading system for countertop use by a user endowed with a human vision system having a critical flicker frequency, said automatic bar code symbol reading system having an object detection mode of operation, a bar code symbol detection mode of operation, and comprising:

a housing mountable relative to a countertop surface, and having a light transmission aperture through which visible light can exit and enter said housing;

object detection means in said housing, for automatically detecting, during said object detection mode, the presence of an object within at least a portion of a scan field defined external to said housing;

laser beam source in said housing for producing, a visible laser beam within said housing;

laser beam directing means in said housing, for directing said visible laser beam through said light transmission aperture and into said scan field;

a scanning mechanism in said housing for scanning, during said bar code symbol detection mode and said bar code symbol reading mode, said visible laser beam across said scan field an a bar code symbol on said detected object,

said scanned visible laser beam flickering in said scan field during said bar code symbol detection mode, at a rate below the critical flicker frequency of the user'"'"'s human visual system so as to improve the visual conspicuousness of said visible laser beam in said scan field during said bar code symbol detection mode of operation;

light detection means in said housing, for detecting the intensity of laser light reflected off said bar code symbol as said visible laser beam is scanned across said scan field and said bar code symbol during said bar code symbol detection and bar code symbol reading modes, and for automatically producing scan data indicative of the detected intensity or said reflected laser light;

scan data processing means for processing produced scan data during said bar code symbol detection mode and said bar code symbol reading mode, so as to detect and decode said bar code symbol on said detected object, and upon detecting and decoding said bar code symbol, automatically producing symbol character data representative of said decoded bar code symbol; and

control means for controlling the operation of said automatic bar code symbol reading system.

7. The automatic bar code symbol reading system of claim 6, wherein said housing comprises a hand-supportable structure supportable in a stand and said hand-supportable structure comprises a head portion and a handle portion, and wherein said laser beam source, said laser beam directing means, said scanning mechanism, and said light detection means are disposed in said head portion.

8. A method of reading bar code symbols using an automatic laser scanning unit having an object detection mode, a bar code symbol detection mode and a bar code symbol reading mode, said method comprising the steps:

(a) supporting said automatic laser scanning unit stationary relative to countertop surface and a user endowed with a human vision system having critical flicker frequency;

(b) bringing an object in a non-contacting relationship with said automatic laser scanning unit so that said object is located within at least a portion of a scan field defined external to said automatic laser scanning unit and said automatic laser scanning unit automatically detects said object with at least a portion or said scan field;

(c) automatically generating an activation signal in response to the detection of said object located in said scan field so that said automatic laser scanning unit is induced into said bar code symbol detection mode;

(d) in response to the generation of said activation signal during step (c),

(1) automatically activating a laser beam source and an electrically driven scanning element in said automatic laser scanning unit so as to produce a visible laser beam which is directed through a light transmission aperture in said automatic laser scanning unit and scanned across said scan field and a bar code symbol on said detected object, and said scanned visible laser beam flickers in said scan field at a rate less than the critical flicker frequency of the user'"'"'s human visual system, so as to improve the visual conspicuousness of said visible laser beam in said scan field as said user visually detection mode;

(2) automatically detecting at said automatic laser scanning unit, the intensity of laser light reflected off said bar code symbol on said detected object, and automatically producing scan data indicative of the detected intensity of said reflected laser light, and

(3) automatically processing produced scan data in order to detect and decode said bar code symbol on said detected object; and

(e) upon detecting and decoding said bar code symbol, automatically producing symbol character data representative of said decoded bar code symbol.

9. The method of claim 8, wherein said bar code symbol has first and second envelope borders, and wherein substep (d)(3) comprises detecting said first and second envelope borders of said bar code symbol and decoding said detected bar code symbol.