US5080456A — Laser scanners with extended working range

Claim 1

Independent Claim 123 words

A bar code scanner comprising: a) a light source for directing a collimated beam of light in a path toward a symbol to be scanned, and a moving optical element in said path to cause the beam of light to move along a scan line; b) optical means in said path for creating a spot of light defined by said beam having a size related to the size of features of said symbol to be scanned, said beam of light exhibiting said spot size over a substantial distance along an axis of said beam, the optical means including a slit in said path perpendicular to the axis of said beam; c) and a light detector positioned to receive light reflected from said symbol.

Claim 2

Dependent Claim 123 words

A bar code scanner comprising: a) a light source for directing a collimated beam of light in a path toward a symbol to be scanned, and a moving optical element in said path to cause the beam of light to move along a scan line; b) optical means in said path for creating a spot of light defined by said beam having a size related to the size of features of said symbol to be scanned, said beam of light exhibiting said spot size over a substantial distance along an axis of said beam, the optical means including a slit in said path perpendicular to the axis of said beam; c) and a light detector positioned to receive light reflected from said symbol.

Claim 3

Dependent Claim 13 words

A scanner according to claim 1 wherein said light source is a laser.

Claim 4

Dependent Claim 39 words

A scanner according to claim 1 wherein said optical means is a solid optical element in the shape of a figure formed by rotation of a line about an axis, said line being at an angle to said axis.

Claim 5

Dependent Claim 13 words

A scanner according to claim 3 wherein said figure is a linear axicon.

Claim 6

Dependent Claim 17 words

A scanner according to claim 3 wherein said beam of light is refracted by said optical means.

Claim 7

Dependent Claim 17 words

A scanner according to claim 3 wherein said beam of light is deflected by said optical means.

Claim 8

Dependent Claim 19 words

A scanner according to claim 3 wherein a central opaque portion is provided at the center of the figure.

Claim 9

Dependent Claim 28 words

A scanner according to claim 1 wherein said optical means is in the shape of a figure defined by rotation of a 4/3 power curve about an axis.

Claim 10

Dependent Claim 19 words

A scanner according to claim 1 wherein said slit extends parallel to a direction of scan of said beam.

Claim 11

Dependent Claim 53 words

A scanner according to claim 1 wherein said symbol is a bar code symbol having bars and spaces extending perpendicular to said scan line, and the size of said light spot as it traverses said scan line on said symbol is not substantially greater than a minimum width of said bars and spaces.

Claim 12

Dependent Claim 27 words

A scanner according to claim 1 wherein said optical means is in the shape of a figure defined by rotation of a logarithmic curve about an axis.

Claim 13

Independent Claim 122 words

A method for scanning a symbol, comprising the steps of: a) generating a collimated light beam and directing said light beam toward a symbol to be read; b) moving said light beam by a moving optical element to generate a scan line across said symbol to be read; c) modifying said light beam in the path toward said symbol to create a spot of light of a size correlated generally with the size of features of said symbol, said spot maintaining a substantially constant size for varying distances to said symbol, over a substantial range of said distances on an optical axis, the step of modifying including passing the light beam through a slit in said path perpendicular to said optical axis.

Claim 14

Independent Claim 122 words

A method for scanning a symbol, comprising the steps of: a) generating a collimated light beam and directing said light beam toward a symbol to be read; b) moving said light beam by a moving optical element to generate a scan line across said symbol to be read; c) modifying said light beam in the path toward said symbol to create a spot of light of a size correlated generally with the size of features of said symbol, said spot maintaining a substantially constant size for varying distances to said symbol, over a substantial range of said distances on an optical axis, the step of modifying including passing the light beam through a slit in said path perpendicular to said optical axis.

Claim 15

Dependent Claim 15 words

A method according to claim 12 wherein said light beam is a laser light beam.

Claim 16

Dependent Claim 15 words

A method according to claim 12 wherein said light beam is scanned across said symbol.

Claim 17

Dependent Claim 45 words

A method according to claim 12 wherein said step of modifying includes directing said light beam through a solid optical element in the shape of a figure formed by rotation of a line about an axis, said line being at an angle to said axis.

Claim 18

Dependent Claim 13 words

A method according to claim 15 wherein said figure is a linear axicon.

Claim 19

Dependent Claim 45 words

A method according to claim 12 wherein said step of modifying includes deflecting said light beam by a solid optical element in the shape of a figure formed by rotation of a line about an axis, said line being at an angle to said axis.

Claim 20

Dependent Claim 37 words

A method according to claim 12 wherein said step of modifying includes directing said light beam through a solid optical element in the shape of a figure defined by rotation of a 4/3-power curve about an axis.

Claim 21

Dependent Claim 38 words

A method according to claim 12 wherein said symbol has features extending perpendicular to said scan line, and said step of modifying includes passing said light beam through a slit extending perpendicular to said features of said symbol.

Claim 22

Dependent Claim 37 words

A method according to claim 12 wherein said step of modifying includes directing said light beam through a solid optical element in the shape of a FIGURE defined by rotation of a logarithmic curve about an axis.

Claim 23

Dependent Claim 160 words

Apparatus for detecting indicia having portions of different light reflectivity such as a bar code symbol comprising: (a) a light source operable to emit a substantially monochromatic collimated beam of light having a predetermined diffraction pattern; (b) optical means disposed in the path of the beam of light for modifying the diffraction pattern of the light beam and creating a beam spot of a predetermined diameter, said diameter being relatively constant over a predetermined distance along an optical axis passing through the center of and normal to said optical means; (c) means for directing the beam spot to said indicia, said indicia lying in a reference plane which is substantially normal to the optical axis, said means being adapted to scan spatially adjacent portions of said indicia; and (d) sensor means for detecting at least a portion of light of variable intensity reflected off the indicia, and for generating an electrical signal indicative of the intensity of said detected light.

Claim 24

Dependent Claim 160 words

Apparatus for detecting indicia having portions of different light reflectivity such as a bar code symbol comprising: (a) a light source operable to emit a substantially monochromatic collimated beam of light having a predetermined diffraction pattern; (b) optical means disposed in the path of the beam of light for modifying the diffraction pattern of the light beam and creating a beam spot of a predetermined diameter, said diameter being relatively constant over a predetermined distance along an optical axis passing through the center of and normal to said optical means; (c) means for directing the beam spot to said indicia, said indicia lying in a reference plane which is substantially normal to the optical axis, said means being adapted to scan spatially adjacent portions of said indicia; and (d) sensor means for detecting at least a portion of light of variable intensity reflected off the indicia, and for generating an electrical signal indicative of the intensity of said detected light.

Claim 25

Dependent Claim 103 words

Apparatus as defined in claim 21, wherein said optical means comprises: (a) an axicon having a predetermined index of refraction and a predetermined cross section angle, being operable to create the beam spot of constant diameter along the predetermined distance along the optical axis by focusing the beam of light along a continuous series of points along the predetermined distance along the optical axis; and (b) a slit having a predetermined width and being adapted to pass the beam spot created by the axicon and to restrict the passage of light exterior to the beam spot in a direction perpendicular to the slit.

Claim 26

Dependent Claim 166 words

Apparatus for reading an optically coded symbol comprising: (a) a laser light source operable to emit a beam of collimated coherent light directed in a path toward said symbol; (b) an axicon in said path adapted to receive the light beam and to generate a diffraction pattern comprising a central beam spot having a predetermined diameter and exterior rings surrounding the beam spot, said beam spot and diffraction pattern being of substantially constant size along a predetermined distance along an optical axis, said optical axis being normal to and passing through the center of said axicon; (c) a slit of a predetermined width in said path adapted to limit the spatial extent of the diffraction pattern generated by the axicon; (d) means for directing the beam spot onto and across the symbol to be read; and (e) sensor means operative for detecting at least a portion of light reflected off the symbol, and for generating an electrical signal indicative of the intensity of the detected light.

Claim 27

Dependent Claim 166 words

Apparatus for reading an optically coded symbol comprising: (a) a laser light source operable to emit a beam of collimated coherent light directed in a path toward said symbol; (b) an axicon in said path adapted to receive the light beam and to generate a diffraction pattern comprising a central beam spot having a predetermined diameter and exterior rings surrounding the beam spot, said beam spot and diffraction pattern being of substantially constant size along a predetermined distance along an optical axis, said optical axis being normal to and passing through the center of said axicon; (c) a slit of a predetermined width in said path adapted to limit the spatial extent of the diffraction pattern generated by the axicon; (d) means for directing the beam spot onto and across the symbol to be read; and (e) sensor means operative for detecting at least a portion of light reflected off the symbol, and for generating an electrical signal indicative of the intensity of the detected light.

Claim 28

Dependent Claim 25 words

Apparatus as defined in claim 23, further comprising means for converting said electrical signal into a digital representation of the data encoded in the symbol.

Claim 29

Independent Claim 69 words

A method for scanning a symbol, comprising the steps of: (a) generating a substantially monochromatic beam of collimated light having a predetermined diffraction pattern; (b) modifying the diffraction pattern of the beam of light to create a beam spot of a substantially constant diameter which extends along a predetermined distance along the path of said beam; and (c) directing the extended beam spot onto a symbol to be read.

Claim 30

Independent Claim 69 words

A method for scanning a symbol, comprising the steps of: (a) generating a substantially monochromatic beam of collimated light having a predetermined diffraction pattern; (b) modifying the diffraction pattern of the beam of light to create a beam spot of a substantially constant diameter which extends along a predetermined distance along the path of said beam; and (c) directing the extended beam spot onto a symbol to be read.

Claim 31

Dependent Claim 73 words

A method as defined in claim 25, wherein said step of modifying the diffraction pattern of the beam of light includes: (a) adapting an axicon to focus the beam of light along a continuous series of points along a predetermined extent of an optical axis; and (b) adapting a slit to limit the spatial extent of the diffraction pattern generated by the axicon in a direction perpendicular to the symbol to be read.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1995-01-13	1995-07-15	1996-01-14	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1999-01-13	1999-07-15	2000-01-14	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2003-01-13	2003-07-15	2004-01-14	$7700.00	Window Closed / Lapsed

Laser scanners with extended working range

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