Portable laser scanning arrangement for and method of evaluating and validating bar code symbols

• US 4,251,798 A
• Filed: 05/31/1978
• Issued: 02/17/1981
• Est. Priority Date: 05/31/1978
• Status: Expired due to Term

• Current Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Brown, George, Barkan, Edward, Swartz, Jerome, Delfine, Frank, Harrison, Shelley A.
• Primary Examiner(s): Boudreau, Leo H.
• Application Number:
  US05/911,171
• Time in Patent Office: 993 Days
• Field of Search: 350/6.5-6.9, 250/568, 250/569, 250/555, 250/556, 235/454, 235/455, 235/462, 235/463, 235/472, 340/146.3 F, 340/146.3 Z, 340/146.3 SY
• US Class Current: 235/462.2
• 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

Abstract

Laser light reflected from a bar code symbol pattern is detected by a photodetector mounted in a portable scanning head of a laser scanning system. By selecting appropriate threshold values on the analog signal generated by the photodetector, the analog signal is converted to a series of pulses, each pulse width accurately corresponding to the width of a bar from the scanned pattern. A plurality of functions can be determined from the series of pulses, each function being independently selected by keyboard entry from the head, displayed on the head, and/or recorded by a printer remote from the head. Single line or multiple line scans in two orthogonal directions relative to the pattern may be selected. A bimorph or speaker-type oscillatory element may be utilized as a miniature scanning element. Circuitry for synchronizing scanning along both axes, and for generating a signal to drive the bimorph in a uniform, constant velocity manner is also disclosed.

Claims

1. In a laser scanning system for evaluating and validating bar code symbols, a portable laser scanning head comprising:

(a) means on said head for directing a laser light beam towards a bar code symbol for reflection therefrom;

(b) means on said head for detecting the intensity of the light reflected from the symbol, and for generating an electrical signal indicative of the detected intensity of the reflected light;

(c) means on said head for selecting a characteristic of the symbol;

(d) means responsive to selection of the characteristic for decoding the electrical signal, and for generating data descriptive of the decoded signal; and

(e) means on said head for displaying the generated data, whereby the mounting of the displaying means and the selecting means on the head facilitates data reading and characteristic selection at the site of the symbol to be analyzed.

2. The portable laser scanning head of claim 1, wherein said directing means includes a laser;

and further comprising a portable housing in which said laser is mounted; and

also comprising means for holding said housing for movement towards and away from the symbol to be analyzed, including a carrying handle remote from and out of thermal contact with said laser.

3. The portable laser scanning head of claim 2;

and further comprising a shock mounting support plate which subdivides the interior of said portable housing, said laser being mounted on one side of said support plate.

4. The portable laser scanning head of claim 1;

and further comprising resilient contact means on said head for conforming the latter to the surface on which the symbol is imprinted.

5. The portable laser scanning head of claim 1;

and further comprising a housing exit port for juxtaposition with the symbol to be analyzed, and a housing viewport through which the juxtaposed symbol can be observed; and

also comprising means for illuminating the viewport, and means for disabling said displaying means upon illumination of the viewport.

6. The portable laser scanning head of claim 5;

and further comprising a carrying handle on said head, and wherein said disabling means includes a switch proximally located adjacent said handle.

7. The portable laser scanning head of claim 1, wherein said displaying means includes a pair of display elements;

and further comprising means for formatting the generated data such that each display element has a different portion of the generated data.

8. In a laser scanning system for scanning bar code symbols, a portable laser scanning head comprising:

(a) means in said portable head for directing a laser light beam towards a bar code symbol which has bars and spaces successively spaced apart of each other along a predetermined direction; and

(b) multiple line scanning means for generating a raster-type scan pattern, including

(i) first miniature scan means in said portable head for moving the laser light beam lengthwise of the symbol along said predetermined direction, and

(ii) second miniature scan means in said portable head for moving the laser light beam in transverse direction substantially orthogonal to said predetermined direction for a stroke distance at least equal to one-half of the transverse height of the symbol along said orthogonal direction.

9. The portable laser scanning head of claim 8;

and further comprising single line scanning means for generating a single scan line which extends lengthwise of the symbol along said predetermined direction; and

also comprising means for alternately selecting between said single line scanning means and said multiple line scanning means.

10. The portable laser scannng head of claim 8;

and further comprising means for synchronizing the movement of said laser light beam by said first scan means between a pair of end limiting positions, with the movement of said laser light beam by said second scan means, said synchronizing means including means at one of said end limiting positions for sensing the presence of said light beam at said one end limiting position, and for generating an electrical signal in response to such sensing.

11. The portable laser scanning head of claim 8, wherein one of said scan means is a ferro-electric-type bimorph mounted on said head for movement relative thereto;

and further comprising drive means for moving said bimorph in a predetermined cyclic manner over a predetermined time period.

12. The portable laser scanning head of claim 11, wherein said drive means includes circuit means for generating a voltage having a triangular waveform, said circuit means including means for generating a substantially constant high voltage level for one-half said time period, and for generating a substantially constant low voltage level for the other half of said time period;

and means for integrating said high and said low voltage levels to thereby generate said triangular waveform.

13. The portable laser scanning head of claim 11;

and further comprising a support plate on which said bimorph is mounted, a leaf spring on which a reflecting mirror is mounted, and a flexible strip connected to said leaf spring and said support plate.

14. The portable laser scanning head of claim 8, wherein one of said scan means is a speaker-type element having a movable flexible diaphragm;

and further comprising drive means for moving said flexible diaphragm in a predetermed cyclic manner.

15. The portable laser scanning head of claim 8, wherein said scan pattern is comprised of a plurality of generally parallel, equidistantly spaced-apart scan lines which are substantially linear and do not intersect each other over the entire field of said raster-type scan pattern as considered in both the predetermined and the orthogonal directions.

16. A laser scanning system for evaluating and validating bar code symbols, comprising:

(a) a console;

(b) a portable laser scanning head movable relative to and operatively connected with said console;

(c) means on said head for directing a laser light beam towards a bar code symbol for reflection therefrom;

(d) means on said head for detecting the intensity of the light reflected from the symbol, and for generating an electrical signal indicative of the detected intensity of the reflected light;

(e) means on said head for selecting a characteristic of the symbol;

(f) means responsive to selection of the characteristic for decoding the electrical signal, and for generating data descriptive of the decoded signal; and

(g) means on said console for recording the generated data, said recording means including a printer operative for recording each and every of the generated data in response to operation of said selecting means.

17. In a laser scanning system for reading bar code symbols, a portable laser scanning head, comprising:

(a) a portable hand-held housing;

(b) means in the portable housing for directing a laser light beam along a light path towards a bar code symbol which is located in the vicinity of a reference plane that is located exteriorly of the portable housing, said directing means including

(i) light source means for generating the laser light beam, said light source means being mounted within and enclosed on all sides by the housing; and

(ii) optic means for optically modifying the laser light beam to produce a scanning beam spot, said optic means including an optical train in the light path and operative for producing the scanning beam spot with an axial cross-section whose size is generally maintained in the vicinity of the reference plane over a working distance which is at least one-half inch as measured with respect to the reference plane;

(c) miniature multiple line scanning means in the portable housing for generating a raster-type scan pattern which has a height at least on the order of 3/8 inches and which is comprised of a plurality of generally parallel, equidistantly spaced-apart scan lines by sweeping the laser light beam across the bar code symbol for reflection therefrom over a field of view which has a linear dimension up to on the order of four inches, said miniature line scanning means including a miniature scanning element in the light path and operative for changing the sweep direction of the laser light beam in a predetermined cyclic manner;

(d) means in the portable housing for detecting the intensity of light reflected from the bar code symbol, and for generating an electrical signal indicative of the detected intensity of the reflected light; and

(e) means in the portable housing to process the electrical signal for generating therefrom data descriptive of the bar code symbol.

18. The portable laser scanning head of claim 17, wherein said light source means constitutes an unpackaged lightweight laser tube;

and further comprising means for mounting the laser tube in shock-resistant relationship with the portable housing.

19. The portable laser scanning head of claim 18, wherein said laser tube mounting means includes a shock mounting support plate mounted within the interior of the portable housing, and a plurality of shock mounting springs mounted on the support plate and being located at opposite sides of the laser tube for supporting the same in shock-resistant relationship relative to the housing.

20. The portable laser scanning head of claim 17;

and further comprising handle means mounted on the portable housing for permitting a user to transport the latter by hand towards and away from the symbol to be read.

21. The portable laser scanning head of claim 20, wherein said light source means constitutes a Helium-Neon laser tube, and wherein said handle means includes a carrying handle mounted remote from and out of thermal contact with the laser tube.

22. The portable laser scanning head of claim 17;

and furthr comprising a housing exit port for juxtaposition with the symbol to be read, and a housing viewport through which the juxtaposed symbol can be observed; and

also comprising means for illuminating the viewport, and means for disabling said displaying means upon illumination of the viewport.

23. The portable laser scanning head of claim 22;

and further comprising a carrying handle on said housing, and wherein said disabling means includes a switch proximally located adjacent said handle.

24. The protable laser scanning head of claim 17;

and further comprising means for selecting a characteristic of the symbol; and

wherein said processing means is operative for generating data descriptive of the selected characteristic so as to operate the laser scanning system as a reading, evaluating and analyzing system.

25. The portable laser scanning head of claim 17;

and further comprising keyboard means for selecting a characteristic of the symbol, said keyboard means being mounted on the portable housing for facilitating characteristic selection at the site of the symbol to be read.

26. The portable laser scanning head of claim 17;

and further comprising display means for displaying the generated data, said display means being mounted on the portable housing for facilitating data reading at the site of the symbol to be read.

27. The portable laser scanning head of claim 26, wherein said displaying means includes a pair of display elements;

and further comprising means for formatting the generated data such that each display element has a different portion of the generated data.

28. The portable laser scanning head of claim 17;

and further comprising means on said housing for selecting a characteristic of the symbol;

wherein said data generating means includes means responsive to selection of the characteristic for decoding the electrical signal, and for generating data descriptive of the decoded signal; and

further comprising means on said housing for displaying the generated data, whereby the mounting of the displaying means and the selecting means on the housing facilitates data reading and characteristic selection at the site of the symbol to be read.

29. The portable laser scanning head of claim 17, wherein said miniature multiple line means includes first miniature scan means in said portable housing for moving the laser light beam lengthwise of the symbol in a predetermined direction along which the symbol is elongated, and second miniature scan means in said portable housing for moving the laser light beam in transverse direction substantially orthogonal to said predetermined direction for a stroke distance at least equal to one-half of the transverse height of the symbol along said orthogonal direction.

30. The portable laser scanning head of claim 29;

and further comprising means for selecting a characteristic of the symbol; and

wherein said processing means is operative for generating data descriptive of the selected characteristic so as to operate the laser scanning system as a reading, evaluating and analyzing system; and

wherein said scan pattern is comprised of a plurality of generally parallel, equidistantly spaced-apart scan lines which are substantially linear and do not intersect each other over the entire field of said raster-type scan pattern as considered in both the predetermined and the orthogonal directions.

31. The portable laser scanning head of claim 30;

and further comprising means for disabling the second miniature scan means to thereby convert the multiple line scanning means to single line scanning means for generating a single scan line which extends lengthwise of the symbol along said predetermined direction; and

also comprising means for alternately actuating and deactuating and disabling means so as to select between the single scan line and the plurality of scan lines.

32. A miniature light beam scanning device, comprising:

(a) a stationary support plate having a pair of spaced-apart support regions;

(b) a displaceable component having a cantilevered end region mounted at one of the support regions of the support plate, and a free end region movable relative to the cantilevered end region;

(c) a mirror component having a reflective surface positioned in the path of a light beam to be scanned; and

(d) means for mounting the mirror component for amplified angular movement relative to the support plate, said mounting means including

(i) elongated resilient support means having a first end region operatively connected to the free end region of the displaceable component, a second end region operatively connected to the other support region of the support plate, and an intermediate flexible region on which the mirror component is mounted for amplified movement as compared to the movement of the free end region of the displaceable component.

33. The scanning device of claim 32, wherein said resilient support means includes a resilient leaf spring and a flexible tape.

34. The scanning device of claim 32, wherein said displaceable component is a ferro-electric-type oscillatory bimorph;

and further comprising means for driving the bimorph in a predetermined cyclic manner, said amplified movement constituting a scanning distance on the order of at least one-half inch.

35. The scanning device of claim 32, wherein said displaceable component includes a ferro-electric-type oscillatory bimorph;

and further comprising means for operating the bimorph in a resonant, closed loop, electro-mechanical configuration, said amplified movement constituting a scanning distance on the order of at least one inch.

36. The scanning device of claim 32, wherein said displaceable component includes a resilient element and a speaker-type oscillator having a movable flexible disphragm operatively interconnecting the latter with the free end region of the resilient element;

and further comprising means for moving the diaphragm together with the resilient element in a predetermined cyclic manner, said amplified movement constituting a scanning distance on the order of at least one-half inch.

37. A miniature light beam scanning device comprising:

(a) a ferro-electric-type oscillatory bimorph;

(b) means for operative the bimorph for movement in a resonant, closed loop electro-mechanical configuration;

(c) a mirror component having a reflective surface positioned in the path of a light beam to be scanned; and

(d) means operatively connected between the mirror component and the bimorph for moving the mirror over a scanning distance on the order of at least one inch.