Portable laser diode scanning head

• US 4,835,374 A
• Filed: 08/09/1988
• Issued: 05/30/1989
• Est. Priority Date: 02/28/1985
• Status: Expired due to Term

• Current Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Barkan, Edward, Swartz, Jerome, Metlitsky, Boris, Barkan, Eric F., Shepard, Howard M., Adelson, Alexander M., Krichever, Mark J.
• Primary Examiner(s): Pitts, Harold I.
• Application Number:
  US07/230,746
• Time in Patent Office: 294 Days
• Field of Search: 235/472
• US Class Current: 235/472.01
• CPC Class Codes: G06K 2207/1011 Aiming
• CPC Class Codes: G06K 7/10633 by oscillation
• CPC Class Codes: G06K 7/10881 constructional details of hand-held scanners

Abstract

A portable laser diode scanning head, aimable at each symbol to be read, emits and receives non-readily-visible laser light, and is equipped with a trigger-actuated aiming light arrangement for visually locating and tracking each symbol. A compact laser diode optical train and an optical folded path assembly, as well as an interchangeable component design and an integral window construction for the head also are disclosed.

Claims

1. In a laser scanning system for reading symbols, a laser scanning head comprising:

(a) means including an actuatable laser light source. mounted in the head and operative, when actuated, for generating an incident laser beam whose light is non-readily visible to a user;

(b) optic means mounted in the head for optically forming and directing said non-readily-visible incident laser beam along a first optical path toward a reference plane located exteriorly of the head, and to a symbol located in a working distance range in the vicinity of the reference plane, thereby reflecting off the symbol non-readily-visible reflected laser light, at least a returning portion of which travels along a second optical path away from the symbol, back toward the head;

(c) actuatable scanning means mounted in the head, operative, when actuated, for repetitively scanning the symbol in a scan across the symbol, said returning portion of said reflected laser light having a variable intensity over the scan;

(d) sensor means mounted in the head for detecting the variable intensity of said returning portion of said reflected laser light over a field of view, and for generating an electrical analog signal indicative of the detected variable light intensity;

(e) said scanning means being operative for scanning at least one of said incident laser beam and said field of view;

(f) signal processing means mounted in the head for processing the analog electrical signal, and for generating a processed signal indicative of the symbol;

(g) means including an actuatable aiming light source mounted in the head and operative, when actuated, for generating an aiming light beam whose light is readily visible to the user;

(h) aiming means mounted in the head for directing said aiming light beam along an aiming light path from the aiming light source toward the reference plane and to the symbol to visibly illuminate at least a part of the symbol, said aiming light path lying within at least one of said optical paths in the portion of the latter which lies exteriorly of the head; and

(i) manually-actuatable trigger means on the head and operatively connected to, and operative for actuating, the actuatable sources, the scanning means, the sensor means and the signal processing means to initiate a reading of the partly illuminated symbol upon manual actuation of the trigger means by the user, said trigger means being actuatable for each symbol to be read, each symbol in its respective turn.

2. The head as recited in claim 1, wherein the actuatable laser light source is a semiconductor gallium arsenide-based laser diode operative for emitting said non-readily visible incident laser beam with a wavelength on the order of 7800 Angstrom units, and with a non-radially symmetrical beam cross-section which diverges downstream along said first optical path.

3. The head as recited in claim 2 wherein the optic means includes a focusing lens and an aperture stop positioned in said first optical path, said aperture stop having a cross-section smaller than the beam cross-section for optically forming said non-radially symmetrical beam cross-section to a smaller beam cross-section at the aperture stop, said optic means being operative for focusing said incident laser beam to have a beam cross-section of a predetermined size within the working distance range.

4. The head as recited in claim 3, wherein the optic means includes a single focusing lens, wherein the aperture stop has a generally circular cross-section, and wherein the aperture stop is located downstream and in the immediate vicinity of the lens.

5. The head as recited in claim 3, wherein the optic means further includes means for adjustably and jointly positioning the lens and the aperture stop at a predetermined spacing from the diode, and locating the lens at the aperture stop at said predetermined spacing.

6. The head as recited in claim 1, wherein the scanning means includes an actuatable reciprocally oscillatable scanning mirror operative, when actuated, to oscillate at a plurality of times per second and to initiate a repetitive and cyclical scanning across the symbol over the field of view;

and wherein the trigger means is operatively connected to the actuatable scanning mirror for reciprocally oscillating the latter upon manual actuation of the trigger means by the user.

7. The head as recited in claim 6;

and further comprising an actuatable reciprocally oscillatable spherical mirror operatively connected to the trigger means and operative, when actuated by the trigger means, to oscillate at a plurality of times per second, to collect said returning portion of said reflected laser light over the field of view, and to direct said collected returning portion to the sensor means; and

wherein the aiming means includes an optical element positioned in said second optical path between the spherical mirror and the sensor means, said optical element being transmissive to said collected returning portion of said reflected laser light, thereby permitting said collected returning portion to be detected by the sensor means; and

wherein said aiming means directs said aiming light beam to the spherical mirror for reflection therefrom along said aiming light path; and

wherein the optical element also is positioned in said aiming light path between the aiming light source and the spherical mirror, said optical element being reflective to said aiming light beam, thereby reflecting said aiming light beam to the spherical mirror.

8. The head as recited in claim 7, wherein the scanning mirror is substantially planar, and wherein the spherical mirror is generally concave, and wherein the substantially planar scanning mirror and the generally concave spherical mirror are of one-piece construction.

9. The head as recited in claim 1, wherein the aiming means includes single static beam means stationarily mounted in the head and operative for directing said aiming light beam to the symbol to visibly illuminate thereon a spot region within the field of view prior to and during the scan.

10. The head as recited in claim 1, wherein the aiming light beam generating means includes another actuatable aiming light source mounted in the head and operative, when actuated by the trigger means, for generating another aiming light beam whose light is readily visible to the user;

and wherein the aiming means directs said other aiming light beam along another aiming light path from said other aiming light source toward the reference plane and to the symbol to visibly illuminate another part thereof; and

wherein the aiming means includes twin static beam means stationarily mounted in the head and operative for directing both aiming light beams to the same symbol to visibly illuminate thereon a pair of spot regions that are within, and spaced apart of each other along, the field of view, both prior to and during the scan.

11. The head as recited in claim 7, wherein the aiming means directs said aiming light beam to the spherical mirror operative, when actuated by the trigger means, to focus and to dynamically sweep said aiming light beam across the symbol to visibly illuminate thereon a line region extending along the field of view during the scan.

12. The head as recited in claim 7, wherein the spherical mirror has a stationary state and an oscillating state;

and wherein the aiming means directs said aiming light beam to the spherical mirror in the stationary state for focusing and reflecting said aiming light beam to the symbol to visibly illuminate thereon a spot region in the field of view prior to the scan, and to the spherical mirror in the oscillating state for focusing and dynamically sweeping said aiming light beam across the symbol to visibly illuminate thereon a line region extending along the field of view during the scan.

13. The head as recited in claim 1, wherein the trigger means is actuatable from an off state to a first operational state in which the trigger means at least actuates the aiming light source, and thereupon to a second operational state in which the trigger means at least actuates the laser light source.

14. The head as recited in claim 13, wherein the aiming means directs said aiming light beam to the symbol in the first operational state of the trigger means to visibly illuminate a spot region within the field of view on the symbol the symbol and aim the head thereat prior to the scan, to locate the symbol and aim the head thereat prior to the scan, and in the subsequent second operational state of the trigger means to visibly illuminate a line region extending along the field of view on the symbol to dynamically track the symbol during the scan.

15. The head as recited in claim 14, wherein the trigger means comprises switching means having sequential contacts, and a manually-depressible trigger operative, when depressed to an initial extent, to close one of the contacts to define the first operational state and, when depressed to a further extent, to sequentially close the other of the contacts to define the subsequent second operational state.

16. The head as recited in claim 1, wherein the aiming light source is a light emitting diode.

17. The head as recited in claim 1, wherein the head is generally gun-shaped and has a hollow barrel portion and a hollow handle portion.

18. The head as recited in claim 17, wherein the processed signal is a digitized electrical signal;

and wherein the laser beam generating means, optic means, scanning means, sensor means, signal processing means, aiming light beam generating means, and aiming means are all mounted within the barrel portion.

19. The head as recited in claim 18;

and further comprising actuatable decode/control means mounted in the handle portion and operative, when actuated, for decoding the digitized signal to data descriptive of the symbol being read, for determining a successful decoding of the symbol being read, and for terminating the reading of the symbol being read upon the determination of the successful decoding thereof; and

wherein the trigger means is operatively connected to, and is operative for actuating, the decode/control means for each symbol to be read, each symbol in its respective turn; and

further comprising an electrical interlock between the barrel the decode/control means in the handle portion to the signal processing means in the barrel portion when the handle portion is mounted on the latter.

20. The head as recited in claim 19;

and further comprising local data storage means mounted in the handle portion and operatively connected to the decode/control means for storing multiple data from the symbol which have been read.

21. The head as recited in claim 19, wherein the system includes a host computer having a memory base, and an and the host computer, and wherein the decode/control means is operative for conducting each data corresponding to a respective symbol along the conductor for storage in the memory base after each determination of a successful decoding of the respective symbol.

22. The head as recited in claim 20, wherein the system includes a host computer having a memory base, and an electrical cable having a conductor connected between the head and the host computer, and wherein decode/control means is operative for conducting the multiple data stored in the local data storage means along the conductor for storage in the memory base.

23. The head as recited in claim 20, wherein the hollow handle portion has means for interchangeably receiving at least one of the decode/control means and the local data storage means.

24. The head as recited in claim 1, wherein the laser beam generating means and the aiming light beam generating means include means for electrically powering the laser light source and the aiming light source, said powering means being detachably mounted on the head.

25. In a laser scanning system for reading symbols by aiming at each symbol a hand-held laser scanning head of the type including:

(A) means mounted in the head for generating an incident laser beam;

(B) optic means mounted in the head for optically forming and directing said incident laser beam along a first optical path toward a reference plane located exteriorly of the head, and to a symbol located in a working distance range in the vicinity of the reference plane, thereby reflecting off the symbol reflected laser light, at least a returning portion of which travels along a second optical path away from the symbol back toward the head;

(C) actuatable scanning means mounted in the head, operative, when actuated, repetitively scanning the symbol in a scan across the symbol, said returning portion of said reflected laser light having a variable intensity over the scan;

(D) sensor means mounted in the head for detecting the variable intensity of said returning portion of said reflected laser light over a field of view, and for generating an electrical analog signal indicative of the detected variable light intensity;

(E) said scanning means being operative for scanning at least one of said incident laser beam and said field of view;

(F) signal processing means mounted in the head for processing the analog electrical signal, and for generating processed signal indicative of the symbol; and

(G) manually-actuatable trigger means on the head operatively connected to, and operative for actuating, the incident laser beam generating means, the scanning means, the sensor means, and the signal processing means to initiate a reading of the symbol upon manual actuation of the trigger means by the user, said trigger means being actuatable for each symbol to be read, each symbol in its respective turn;

an aiming light arrangement for visually locating, and for aiming the head at, each symbol to be read when said incident laser beam and said reflected laser light are not readily visible to the user, said aiming light arrangement comprising;

(a) means including an actuatable aiming light source mounted in the head and operatively connected to the trigger means, and operative, when actuated by the trigger means, for generating an aiming light beam whose light is readily visible to the user; and

(b) aiming means mounted in the head for directing said aiming light beam along an aiming light path from the aiming light source toward the reference plane and to each symbol to visibly illuminate at least a part of the respective symbol and locate the latter, said aiming light path lying within at least one of said optical paths in the portion of the latter which lies exteriorly of the head to assist the user in correctly aiming the head at the respective symbol to be read.

26. The aiming light arrangement as recited in claim 25, wherein the aiming means includes a stationary directing element in the aiming light path within the head and operative for directing said aiming light beam to the respective symbol to visibly illuminate thereon a spot region within the field of view, said spot region being illuminated both prior to the scan to locate the respective symbol before the reading thereof, and during the scan to locate the respective symbol during the reading thereof.

27. The aiming light arrangement as recited in claim 25, wherein the aiming light beam generating means includes another actuatable aiming light source mounted in the head and operative, when actuated by the trigger means, for generating another light beam whose light is readily visible to the user;

and wherein the aiming means light beam along another aiming light path from said other aiming light source toward the reference plane and to each symbol to visibly illuminate another part thereof; and

wherein the aiming means includes at least one stationary directing element in each of the aiming light paths within the head, and operative for directing both aiming light beams to the same respective symbol to visibly illuminate thereon a pair of spot regions that are within, and spaced apart Of each other along, the field of view, said spot regions being illuminated both prior to and during the scan to locate and track the respective symbol both before and during the reading thereof.

28. The aiming light arrangement as recited in claim 25, wherein the aiming means includes a reciprocally oscillatable directing element in the aiming light path within the head and operative, when actuated by the trigger means, for dynamically sweeping said aiming light beam across the respective symbol to visibly illuminate thereon a line region extending along the field of view, said line region be illuminated during the scan to track the respective symbol during the reading thereof.

29. The aiming light arrangement as recited in claim 25, wherein the aiming means includes a reciprocally oscillatable directing element in the aiming light path within the head;

and wherein the trigger means is actuatable from an off state, to a first operational state in which the trigger means actuates the aiming light source and in which the trigger means directs said aiming light beam to the directing element for direction therefrom to the respective symbol to visibly illuminate thereon a spot region within the field of view prior to the scan to locate the respective symbol before the reading thereof, and to a second operational state in which the trigger means actuates the laser beam generating means, the scanning means, the sensor means, and the signal processing means and also moves the directing element and in which the moving directing element dynamically sweeps said aiming light beam across the respective symbol to visibly illuminate thereon a line region extending along the field of view, said line. region being illuminated during the scan to track the respective symbol during the reading thereof.

30. The aiming light arrangement as defined in claim 25, wherein said aiming light path lies, at least in part, within at least one of said optical paths within the head to provide a compact, efficient, folded, integrated optical assembly.