High-speed scanning arrangement with high-frequency, low-stress scan element

• US 5,412,198 A
• Filed: 11/08/1991
• Issued: 05/02/1995
• Est. Priority Date: 10/30/1989
• Status: Expired due to Term

• Current Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Dvorkis, Paul
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): Duong, Tai V.
• Application Number:
  US07/789,705
• Time in Patent Office: 1,271 Days
• Field of Search: 235/472, 235/462, 235/467, 235/470, 359/198, 359/199, 359/200, 359/212, 359/223, 359/224, 359/225, 359/226
• US Class Current: 235/472.01
• CPC Class Codes: G06K 2207/1011 Aiming
• CPC Class Codes: G06K 2207/1016 Motor control or optical moving unit control
• CPC Class Codes: G06K 2207/1018 Source control
• CPC Class Codes: G06K 7/10564 Light sources
• CPC Class Codes: G06K 7/10584 Source control
• CPC Class Codes: G06K 7/10633 by oscillation
• CPC Class Codes: G06K 7/10643 Activating means
• CPC Class Codes: G06K 7/10653 using flexible or piezoelectric means
• CPC Class Codes: G06K 7/10673 Parallel lines
• CPC Class Codes: G06K 7/10693 for omnidirectional scanning
• 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 7/10871 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 7/1098 the scanning arrangement having a modular construction

Abstract

A scanning arrangement in a scanner which is operative for repetitively scanning indicia having parts of different light reflectivity; for example, such as bar code symbol, and also pertains to the operation of a scanning arrangement of that type at high scanning speeds in two-dimensional or multi-axes scan patterns. A resonance asymmetric scan element (RASE) in which a scan element, which is preferably constituted of a mirror, is in effect attached along the upper side edges thereof to oscillation-imparting spring-means and not at the center of mass of the mirror as heretofore. This allows for higher frequencies of operation for the scan element at lower encountered stresses in that the fast axis of rotation of the scan element or mirror; in essence, the axis of oscillatory rotation about which the mirror is rotated at high frequencies substantially coincides with its center of mass.

Claims

1. In a scanner for reading indicia having portions of different light reflectivity by directing light from said scanner towards said indicia and by collecting reflected light returning from said indicia;

an arrangement for scanning the indicia, comprising;

(a) a scanner component;

(b) holder means mounting said scanner component for angular oscillating movement in first and second scan directions between first and second pairs of scan end positions, said holder means including first and second vibratory means positioned to vibrate in two orthogonal planes and to cooperate for angular oscillating movement in first and second orthogonal scan directions about respective axes for fast and slow oscillatory rotation of said scanner component, said first vibration means comprising a U-shaped spring having a pair of arms, said scanner component being mounted at the first end of one of the arms, said scanner component being configured and said holder means being attached to the scanner component at a position of said component displaced from the center of mass thereof such that the center of mass of said component coincides with the fast axis of oscillatory rotation of said scanner component on said holder means; and

(c) read-start means for simultaneously moving said scanner component in said first and second scan directions to simultaneously angularly oscillate said scanner component between said first and second pair of scan end positions for directing the light along said first and second scan directions so as to resultingly implement a two-dimensional scan pattern over the indicia.

2. The arrangement as claimed in claim 1, wherein said read-start means moves said scanner component in scan directions to resultingly implement a raster scan pattern over the indicia.

3. The arrangement as claimed in claim 1, wherein said read-start means moves said scanner component in scan directions to resultingly implement an omnidirectional scan pattern over the indicia.

4. The arrangement as claimed in claim 1, wherein said second vibratory means comprises a generally planar spring having one end secured to the end of the other arm of said U-shaped spring and the other end secured to a base.

5. The arrangement as claimed in claim 4, wherein said read-start means includes an electrically-operated actuator responsive to actuation thereof for vibrating said holder means to angularly oscillate said component in the first and second scan directions, said actuator including an electromagnetic coil having a passage, and a magnet mounted on the holder means and movable into and out of the passage during actuation of said coil.

6. The arrangement as claimed in claim 5, wherein said magnet is mounted on said holder means proximate the juncture between said other end of the planar spring and said other arm of said U-shaped spring.

7. The arrangement as claimed in claim 5, wherein said first vibratory means is configured to vibrate at a high range of frequencies and wherein said second vibratory means is configured to vibrate at a low range of frequencies to thereby effect a raster-type scan pattern over the indicia in response to driving signal applied to said coil comprising a superposition of a first signal having a frequency within said high range and a second signal having a frequency within said low range.

8. The arrangement as claimed in claim 1, wherein the arms of said U-shaped spring are asymmetrically dimensioned.

9. The arrangement as claimed in claim 5, wherein the center of mass of said scanner component is offset from the axis formed by the electromagnetic coil and said magnet.

10. The arrangement as claimed in claim 4, wherein said U-shaped spring is formed from a bent leaf spring.

11. The arrangement as claimed in claim 1, wherein said scanner component scans said indicia at frequencies within the range of about 150 to 1200 Hz.

12. The arrangement as claimed in claim 1, wherein said indicia is a bar code symbol and said scanner is a bar code reader.

13. The arrangement as claimed in claim 1, wherein the holder means on said arm of said vibratory means mounting said scanner component comprises inwardly folded flexible clip means on opposite side edges of said arm, said scanner component having a neck portion of reduced width at one end thereof grippingly engaged between said respective folded clip means so as to be resiliently mounted on said arm.

14. The arrangement as claimed in claim 13, wherein said folded clip means each have earlobes at a low end thereof receiving the neck portion of said scanner component so as to increase the degree of flexibility in the mounting of said component.

15. The arrangement as claimed in claim 14, wherein said scanner component comprises a scan mirror having a convexly-curved rear surface and a neck portion of narrower width having side edges insertable between said folded clip means whereby advancing said mirror into said holder means causes said clip means to enhance gripping engagement therewith through the imparting of a curvature to the surface portion on said arm extending therebetween in conformance with the curvature of said scan mirror.

16. The arrangement as claimed in claim 13, wherein at least said folded clip means and scanner component mounting means are constituted from a non-ferrous alloy.

17. The arrangement as claimed in claim 16, wherein said non-ferrous alloy comprises a beryllium-copper alloy.

18. A method for reading indicia having portions of differing light reflectivity by directing light from a scanner towards said indicia and by collecting reflected light returning from said indicia through the intermediary of a scanning arrangement for scanning the indicia, comprising:

imparting angular oscillating movement to a scanner component of said scanning arrangement in first and second scan directions between first and second pairs of scan end positions;

vibrating first and second vibratory means in two orthogonal planes so as to cooperate for angular oscillating movement in first and second orthogonal scan directions about respectively axes for fast and slow oscillatory rotation of said scanner component, said scanner component having a center of mass;

positioning said center of mass to coincide with the fast axis of oscillatory rotation of said scanner component on said holder means;

said first vibrating means being configured as a U-shaped spring having a pair of arms, and with the free end of one of the arms being attached to said scanner component at a position thereon displaced from said center of mass; and

simultaneously moving said component responsive to actuation by read-start means in said first and second scan directions to simultaneously angularly oscillate said scanner component between said first and second pair of scan end positions for directing the light along said first and second scan directions so as to resultingly implement a two-dimensional scan pattern over the indicia.

19. The method as claimed in claim 18, wherein said scanner implements a raster scan pattern over said indicia.

20. The method as claimed in claim 18, wherein said scanner component implements an omnidirectional scan pattern over said indicia.

21. The method as claimed in claim 18, wherein said second vibratory means is configured as a generally planar spring having one end secured to the end of the other arm of said U-shaped spring and the other end secured to a base.

22. The method as claimed in claim 21, wherein said read-start means includes an electrically-operated actuator responsive to actuation thereof for vibrating said holder means to angularly oscillate said component in the first and second scan directions, said actuator including an electromagnetic coil having a passage;

and mounting a magnet mounted on the vibratory means so as to be movable into and out of the passage during actuation of said coil.

23. The method as claimed in claim 22, comprising mounting said magnet on said vibratory means proximate the juncture between said other end of the planar spring and said other arm of said U-shaped spring.

24. The method as claimed in claim 22, comprising vibrating said first vibratory means at a high range of frequencies and vibrating said second vibratory means at a low range of frequencies to thereby effect a raster-type scan pattern over the indicia in response to applying a driving signal to said coil comprising superimposing a first signal having a frequency within said high range and a second signal having a frequency within said low range.

25. The method as claimed in claim 18, wherein the arms of said U-shaped spring are asymmetrically dimensioned.

26. The method as claimed in claim 22, wherein the center of mass of said scanner component is offset from the axis formed by the electromagnetic coil and said magnet.

27. The method as claimed in claim 18, wherein said indicia is scanned at frequencies within the range of about 150 to 1200 Hz.

28. The method as claimed in claim 18, wherein said indicia is a bar code symbol and said scanning arrangement is a bar code reader.

29. The method as claimed in claim 18, wherein said free end of the arm of said vibratory means mounting said scanner component includes means having inwardly folded flexible clip means at the opposite edges of said arm, said scanner component having a neck portion of reduced width, opposite side edges of said neck portion being grippingly engaged between said respective folded clip means for resiliently mounting said scanner component on said arm.

30. The method as claimed in claim 29, wherein said folded clip means each have earlobes at a lower end receiving said scanner component so as to increase the degree of flexibility of said clip means towards said lower ends.

31. The method as claimed in claim 30, wherein said scanner component comprises a scan mirror having a convexly-curved rear surface and a reduced width neck portion having side edges insertable into said folded clip means from the ends having said earlobes whereby advancing said mirror into said clip means causes the latter to enhance the gripping engagement with said mirror through the imparting of a curvature to the surface portion on said arm extending therebetween in conformance with the curvature of said scan mirror.

32. The method as claimed in claim 29, wherein at least said folded clip means and mounting means for said scanner component are constituted from a non-ferrous alloy.

33. The method as claimed in claim 32, wherein said non-ferrous alloy comprises a beryllium-copper alloy.

34. In a scanner for reading indicia having portions of different light reflectivity by directing light from said scanner towards said indicia and by collecting reflected light returning from said indicia;

an arrangement for scanning the indicia, comprising;

(a) a scanner component;

(b) holder means mounting said scanner component for angular oscillating movement in first and second scan directions between first and second pairs of scan end positions, said holder means including first and second vibratory means positioned to vibrate in two orthogonal planes and to cooperate for angular oscillating movement in first and second orthogonal scan directions about respective axes for fast and slow oscillatory rotation of said scanner component, said scanner component being configured and being mounted on said holder means such that the center of mass of said component coincides with the fast axis of oscillatory rotation of said scanner component on said holder means; and

(c) read-start means for simultaneously moving said scanner component in said first and second scan directions to simultaneously angularly oscillate said scanner component between said first and second pair of scan end positions for directing the light along said first and second scan directions so as to resultingly implement a two-dimensional scan pattern over the indicia;

wherein

(i) said first vibratory means comprises a U-shaped spring having a pair of arms, said scanner component being mounted at the free end of one of said arms,

(ii) said second vibratory means comprises a generally planar spring having one end secured to the end of the other arm of said U-shaped spring and the other end secured to a base,

( iii ) said read-start means includes an electrically-operated actuator responsive to actuation thereof for vibrating said holder means to angularly oscillate said component in the first and second scan directions, said actuator including an electromagnetic coil having a passage, and a magnet mounted on the holder means and movable into and out of the passage during actuation of said coil, and

(iv) said first vibratory means is configured to vibrate at a high range of frequencies and wherein said second vibratory means is configured to vibrate at a low range of frequencies to thereby effect a raster-type scan pattern over the indicia in response to driving signal applied to said coil comprising a superposition of a first signal having a frequency within said high range and a second signal having a frequency within said low range.

35. In a scanner for reading indicia having portions of different light reflectivity by directing light from said scanner towards said indicia and by collecting reflected light returning from said indicia;

an arrangement for scanning the indicia, comprising;

(a) a scanner component;

(b) holder means mounting said scanner component for angular oscillating movement in first and second scan directions between first and second pairs of scan end positions, said holder means including first and second vibratory means positioned to vibrate in two orthogonal planes and to cooperate for angular oscillating movement in first and second orthogonal scan directions about respective axes for fast and slow oscillatory rotation of said scanner component, said scanner component being configured and being mounted on said holder means such that the center of mass of said component coincides with the fast axis of oscillatory rotation of said scanner component on said holder means; and

(c) read-start means for simultaneously moving said scanner component in said first and second scan directions to simultaneously angularly oscillate said scanner component between said first and second pair of scan end positions for directing the light along said first and second scan directions so as to resultingly implement a two-dimensional scan pattern over the indicia;

wherein

(i) said first vibratory means comprises a U-shaped spring having a pair of arms, said scanner component being mounted at the free end of one of said arms,

(ii) said second vibratory means comprises a generally planar spring having one end secured to the end of the other arm of said U-shaped spring and the other end secured to a base,

(iii) said read-start means includes an electrically-operated actuator responsive to actuation thereof for vibrating said holder means to angularly oscillate said component in the first and second scan directions, said actuator including an electromagnetic coil having a passage, and a magnet mounted on the holder means and movable into and out of the passage during actuation of said coil, and

(iv) the center of mass of said scanner component is offset from the axis formed by the electromagnetic coil and said magnet.

36. In a scanner for reading indicia having portions of different light reflectivity by directing light from said scanner towards said indicia and by collecting reflected light returning from said indicia;

an arrangement for scanning the indicia, comprising;

(a) a scanner component;

(b) holder means mounting said scanner component for angular oscillating movement in first and second scan directions between first and second pairs of scan end positions, said holder means including folded clip means for holding said scanner component and first and second vibratory means positioned to vibrate in two orthogonal planes and to cooperate for angular oscillating movement in first and second orthogonal scan directions about respective axes for fast and slow oscillatory rotation of said scanner component, said scanner component being configured and being mounted on said holder means such that the center of mass of said component coincides with the fast axis of oscillatory rotation of said scanner component on said holder means; and

(c) read-start means for simultaneously moving said scanner component in said first and second scan directions to simultaneously angularly oscillate said scanner component between said first and second pair of scan end positions for directing the light along said first and second scan directions so as to resultingly implement a two-dimensional scan pattern over the indicia;

ps wherein

(i) said first vibratory means comprises a U-shaped spring having a pair of arms, said scanner component being mounted at the free end of one of said arms, and

(ii) said second vibratory means comprises a generally planar spring having one end secured to the end of the other arm of said U-shaped spring and the other end secured to a base.

37. The arrangement as claimed in claim 36, wherein said folded clip means each have earlobes at a low end thereof receiving the neck portion of said scanner component so as to increase the degree of flexibility in the mounting of said component.

38. The arrangement as claimed in claim 37 wherein said scanner component comprises a scan mirror having a convexly-curved rear surface and a neck portion of narrower width having side edges insertable between said folded slip means whereby advancing said mirror into said holder means causes said clip means to enhance gripping engagement theSewith through the imparting of a curvature to the surface portion on said arm extending therebetween in conformance with the curvature of said scan mirror.

39. The arrangement as claimed in claim 36, wherein at least said folded clip means and scanner component mounting means are constituted from a non-ferrous alloy.

40. The arrangement as claimed in claim 39, wherein said nonferrous alloy comprises a beryllium-copper alloy.

41. A method for reading indicia having portions of differing light reflectivity by directing light from a scanner towards said indicia and by collecting reflected light returning from said indicia through the intermediary of a scanning arrangement for scanning the indicia, comprising:

imparting angular oscillating movement to a scanner component of said scanning arrangement in first and second scan directions between first and second pairs of scan end positions;

vibrating first and second vibratory means in two orthogonal planes so as to cooperate for angular oscillating movement in first and second orthogonal scan directions about respectively axes for fast and slow oscillatory rotation of said scanner component, said scanner component having a center of mass;

positioning said center of mass to coincide with the fast axis of oscillatory rotation of said scanner component on said holder means; and

simultaneously moving said component responsive to actuation by read-start means in said first and second scan directions to simultaneously angularly oscillate said scanner component between said first and second pair of scan end positions for directing the light along said first and second scan directions so as to resultingly implement a two-dimensional scan pattern over the indicia,

wherein said scanner component implements an omnidirectional scan pattern over said indicia.

42. A method for reading indicia having portions of differing light reflectivity by directing light from a scanner towards said indicia and by collecting relfected light returning from said indicia through the intermediary of a scanning arrangement for scanning the indicia, comprising:

imparting angular oscillating movement to a scanner component of said scanning arrangement in first and second scan directions between first and second pairs of scan end positions;

vibrating first and second vibratory means in two orthogonal planes so as to cooperate for angular oscillating movement in first and second orthogonal scan directions about respectively axes for fast and slow oscillatory rotation of said scanner component, said scanner component having a center of mass coinciding with the fast axis of oscillatory rotation of said scanner component on said holder means;

simultaneously moving said component responsive to actuation by a read-start means in said first and second scan directions to simultaneously angularly oscillate said scanner component between said first and second pair of scan end positions for directing the light along said first and second scan directions so as to resultingly implement a two-dimensional scan pattern over the indicia,

wherein

(i) said first vibratory means is configured as a U-shaped spring having a pair of arms, comprising mounting said scanner component at the free end of one of said arms;

(ii) said second vibratory means is configured as a generally planar spring having one end secured to the end of the other arm of said U-shaped spring and the other end secured to a base; and

(iii) said read-start means includes an electrically-operated actuator responsive to actuation thereof for vibrating said holder means to angularly oscillate said component in the first and second scan directions, said actuator including an electromagnetic coil having a passage, and mounting a magnet mounted on the vibratory means so as to be movable into and out of the passage during actuation of said coil; and

vibrating said first vibratory means at a high range of frequencies and vibrating said second vibratory means at a low range of frequencies to thereby effect a raster-type scan pattern over the indicia in response to applying a driving signal to said coil comprising superimposing a first signal having a frequency within said high range and a second signal having a frequency within said low range.

43. A method for reading indicia having portions of differing light reflectivity by directing light from a scanner towards said indicia and by collecting reflected light returning from said indicia through the intermediary of a scanning arrangement for scanning the indicia, comprising:

imparting angular oscillating movement to a scanner component of said scanning arrangement in first and second scan directions between first and second pairs of scan end positions;

vibrating first and second vibratory means in two orthogonal planes so as to cooperate for angular oscillating movement in first and second orthogonal scan directions about respectively axes for fast and slow oscillatory rotation of said scanner component, said scanner component having a center of mass;

positioning said center of mass to coincide with the fast axis of oscillatory rotation of said scanner component on said holder means; and

simultaneously moving said component responsive to actuation by read-start means in said first and second scan directions to simultaneously angularly oscillate said scanner component between said first and second pair of scan end positions for directing the light along said first and second scan directions so as to resultingly implement a two-dimensional scan pattern over the indicia,

wherein

(i) said first vibratory means is configured as a U-shaped spring having a pair of arms, comprising mounting said scanner component at the free end of one of said arms; and

(ii) said free end of the arm of said vibratory means mounting said scanner component includes means having inwardly folded flexible clip means at the opposite edges of said arm, said scanner component having a neck portion of reduced width, opposite side edges of said neck portion being grippingly engaged between said respective folded clip means for resiliently mounting said scanner component on said arm.

44. The method as claimed in claim 43, wherein said folded clip means each have earlobes at a lower end receiving said scanner component so as to increase the degree of flexibility of said clip means towards said lower ends.

45. The method as claimed in claim 44, wherein said scanner component comprises a scan mirror having a convexly-curved rear surface and a reduced width neck portion having side edges insertable into said folded clip means from the ends having said earlobes whereby advancing said mirror into said clip means causes the latter to enhance the gripping engagement with said mirror through the imparting of a curvature to the surface portion on said arm extending therebetween in conformance with the curvature of said scan mirror.

46. The method as claimed in claim 43, wherein at least said folded clip means and mounting means for said scanner component are constituted from a non-ferrous alloy.

47. The method as claimed in claim 46, wherein said nonferrous alloy comprises a beryllium-copper alloy.

48. In a scanner for reading indicia having portions of different light reflectivity by directing light from said scanner towards said indicia and by collecting reflected light returning from said indicia;

an arrangement for scanning the indicia, comprising;

(a) a scanner component;

(b) holder means mounting said scanner component for angular oscillating movement in first and second scan directions between first and second pairs of scan end positions, said holder means including first and second vibratory means positioned to vibrate in two orthogonal planes and to cooperate for angular oscillating movement in first and second orthogonal scan directions about respective axes for fast and slow oscillatory rotation of said scanner component, said scanner component being configured and being mounted on said holder means such that the center of mass of said component coincides with the fast axis of oscillatory rotation of said scanner component on said holder means; and

(c) read-start means for simultaneously moving said scanner component in said first and second scan directions to simultaneously angularly oscillate said scanner component between said first and second pair of scan end positions for directing the light along said first and second scan directions so as to resultingly implement a two-dimensional scan pattern over the indicia;

(d) rotating means for rotating said holder means in a third plane;

(e) wherein said rotating means together with said read-start means move said scanner component in scan directions to resultingly implement an omnidirectional scan pattern over the indicia.

49. A method for reading indicia having portions of differing light reflectivity by directing light from said scanner towards said indicia and by collecting reflected light returning from said indicia through the intermediary of an arrangement for scanning the indicia, comprising:

imparting angular oscillating movement to a scanner component of said scanning arrangement in first and second scan directions between first and second pairs of scan end positions;

vibrating first and second vibratory means in two orthogonal planes so as to cooperate for angular oscillating movement in first and second orthogonal scan directions about respectively axes for fast and slow oscillatory rotation of said scanner component, said scanner component having a center of mass coinciding with the fast axis of oscillatory rotation of said scanner component on said holder means; and

simultaneously moving said component responsive to actuation by read-start means in said first and second scan directions to simultaneously angularly oscillate said scanner component between said first and second pair of scan end positions for directing the light along said first and second scan directions so as to resultingly implement a two-dimensional scan pattern over the indicia,

wherein

(i) said first vibratory means is configured as a U-shaped spring having a pair of arms, comprising mounting said scanner component at the free end of one of said arms;

(ii) said second vibratory means is configured as a generally planar spring having one end secured to the end of the other arm of said U-shaped spring and the other end secured to a base;

(iii) said read-start means includes an electrically-operated actuator responsive to actuation thereof for vibrating said holder means to angularly oscillate said component in the first and second scan directions, said actuator including an electromagnetic coil having a passage, and mounting a magnet mounted on the vibratory means so as to be movable into and out of the passage during actuation of said coil; and

(iv) the center of mass of said scanner component is offset from the axis formed by the electromagnetic coil and said magnet.

50. In a scanner for reading indicia having portions of different light reflectivity by directing light from said scanner towards said indicia and by collecting reflected light returning from said indicia;

an arrangement for scanning the indicia, comprising;

(a) a scanner component;

(b) holder means mounting said scanner component for angular oscillating movement in first and second scan directions between first and second pairs of scan end positions, said holder means including first and second vibratory means positioned to vibrate in two orthogonal planes and to cooperate for angular oscillating movement in first and second orthogonal scan directions about respective axes for slow and fast oscillatory rotation of said scanner component, said first vibration means comprising a U-shaped spring having a pair of arms, said scanner component being mounted at the first end of one of the arms, said scanner component being configured and said holder means being attached to the scanner component at a position of said component displaced from the center of mass thereof such that the center of mass of said component coincides with the slow axis of oscillatory rotation of said scanner component on said holder means; and

(c) read-start means for simultaneously moving said scanner component in said first and second scan directions to simultaneously angularly oscillate said scanner component between said first and second pair of scan end positions for directing the light along said first and second scan directions so as to resultingly implement a two-dimensional scan pattern over the indicia.

51. The arrangement as claimed in claim 50, wherein said second vibratory means comprises a generally planar spring having one end secured to the end of the other arm of said U-shaped spring and the other end secured to a base.

52. The arrangement as claimed in claim 51 wherein said read-start means includes an electrically-operated actuator responsive to actuation thereof for vibrating said holder means to angularly oscillate said component in the first and second scan direction, said actuator. including an electromagnetic coil having a passage, and a magnet mounted on the holder means and movable into and out of the passage during actuation of said coil.

53. The arrangement as claimed in claim 52, wherein the center of mass of said scanner component is offset from the axis formed by the electromagnetic coil and said magnet.

54. The arrangement as claimed in claim 53, wherein the offset center of mass of said scanner component provides a restoring force to torsionally vibrate said planar spring along the second scan direction at a high range of frequencies, and said Ushaped spring vibrates along the first scan direction at a low range of frequencies to effect a raster-type scan over the indicia in response to a superimposed high and low frequency driving signal.

55. A method for reading indicia having portions of differing light reflectivity by directing light from a scanner towards said indicia and by collecting reflected light returning from said indicia through the intermediary of a scanning arrangement for scanning the indicia, comprising:

imparting angular oscillating movement to a scanner component of said scanning arrangement in first and second scan directions between first and second pairs of scan end positions;

vibrating first and second vibratory means in two orthogonal planes so as to cooperate for angular oscillating movement in first and second orthogonal scan directions about respectively axes for slow and fast oscillatory rotation of said scanner component, said scanner component having a center of mass;

positioning said center of mass to coincide with the slow axis of oscillatory rotation of said scanner component on said holder means;

configuring said first vibrating means as a U-shaped spring having a pair of arms, with the free end of one of the arms being attached to said scanner component at a position thereon displaced from said center of mass; and

simultaneously moving said component responsive to actuation by read-start means in said first and second scan directions to simultaneously angularly oscillate said scanner component between said first and second pair of scan end positions for directing the light along said first and second scan directions so as to resultingly implement a two-dimensional scan pattern over the indicia.

56. The method as claimed in claim 55, further comprising the step of configuring said second vibratory means as a generally planar spring having one end secured to the end of the other arm of said U-shaped spring and the other end secured to a base.

57. The method as claimed in claim 56, wherein said readstart means includes an electrically-operated actuator responsive to actuation thereof for vibrating said holder means to angularly oscillate said component in the first and second scan directions, said actuator including an electromagnetic coil having a passage;

and

further comprising the step of mounting a magnet on the vibratory means so as to be movable into and out of the passage during actuation of said coil.

58. The method as claimed in claim 57, wherein the center of mass of said scanner component is offset from the axis formed by the electromagnetic coil and said magnet.

59. The method as claimed in claim 58, wherein the offset center of mass of said scanner component provides a restoring force to torsionally vibrate said planar spring along the second scan direction at a high range of frequencies, and said U-shaped spring vibrates along the first scan direction at a low range of frequencies to effect a raster-type scan over the indicia in response to a superimposed high and low frequency driving signal.

60. In a scanner for reading indicia having portions of different light reflectivity by directing light from said scanner towards said indicia and by collecting reflected light returning from said indicia;

an arrangement for scanning the indicia, comprising;

(a) a scanner component;

(b) holder means mounting said scanner component for angular oscillating movement in first and second scan directions between first and second pairs of scan end positions, said holder means including first and second vibratory means positioned to vibrate in two orthogonal planes and to cooperate for angular oscillating movement in first and second orthogonal scan directions about respective axes for slow and fast oscillatory rotation of said scanner component, said scanner component being configured and being mounted on said holder means such that the center of mass of said component coincides with the slow axis of oscillatory rotation of said scanner component on said holder means; and

(c) read-start means for simultaneously moving said scanner component in said first and second scan directions to simultaneously angularly oscillate said scanner component between said first and second pair of scan end positions for directing the light along said first and second scan directions so as to resultingly implement a two-dimensional scan pattern over the indicia;

wherein

(i) said first vibratory means comprises a U-shaped spring having a pair of arms, said scanner component being mounted at the free end of one of said arms,

(ii) said second vibratory means comprises a generally planar spring having one end secured to the end of the other arm of said U-shaped spring and the other end secured to a base,

(iii) said read-start means includes an electrically-operated actuator responsive to actuation thereof for vibrating said holder means to angularly oscillate said component in the first and second scan directions, said actuator including an electromagnetic coil having a passage, and a magnet mounted on the holder means and movable into and out of the passage during actuation of said coil, and

(iv) the center of mass of said scanner component is offset from the axis formed by the electromagnetic coil and said magnet.

61. The arrangement as claimed in claim 60, wherein the offset center of mass of said scanner component provides a restoring force to torsionally vibrate said planar spring along the second scan direction at a high range of frequencies, and said U-shaped spring vibrates along the first scan direction at a low range of frequencies to effect a raster-type scan over the indicia in response to a superimposed high and low frequency driving signal.

62. A method for reading indicia having portions of differing light reflectivity by directing light from said scanner towards said indicia and by collecting reflected light returning from said indicia through the intermediary of an arrangement for scanning the indicia, comprising:

imparting angular oscillating movement to a scanner component of said scanning arrangement in first and second scan directions between first and second pairs of scan end positions;

vibrating first and second vibratory means in two orthogonal planes so as to cooperate for angular oscillating movement in first and second orthogonal scan directions about respectively axes for slow and fast oscillatory rotation of said scanner component, said scanner component having a center of mass;

positioning said center of mass to coincide with the slow axis of oscillatory rotation of said scanner component on said holder means; and

simultaneously moving said component responsive to actuation by read-start means in said first and second scan directions to simultaneously angularly oscillate said scanner component between said first and second pair of scan end positions for directing the light along said first and second scan directions so as to resultingly implement a two-dimensional scan pattern over the indicia,

wherein

(i) said first vibratory means is configured as a U-shaped spring having a pair of arms, comprising mounting said scanner component at the free end of one of said arms;

(ii) said second vibratory means is configured as a generally planar spring having one end secured to the end of the other arm of said U-shaped spring and the other end secured to a base;

(iii) said read-start means includes an electrically-operated actuator responsive to actuation thereof for vibrating said holder means to angularly oscillate said component in the first and second scan directions, said actuator including an electromagnetic coil having a passage, and mounting a magnet mounted on the vibratory means so as to be movable into and out of the passage during actuation of said coil; and

(iv) the center of mass of said scanner component is offset from the axis formed by the electromagnetic coil and said magnet.

63. The method as claimed in claim 62, wherein the offset center of mass of said scanner component provides a restoring force to torsionally vibrate said planar spring along the second scan direction at a high range of frequencies, and said U-shaped spring vibrates along the first scan direction at a low range of frequencies to effect a raster-type scan over the indicia in response to a superimposed high and low frequency driving signal.