WO2013019216A1

WO2013019216A1 - Miniature barcode scanning module for a barcode reading device

Info

Publication number: WO2013019216A1
Application number: PCT/US2011/046244
Authority: WO
Inventors: Duan ZHIHUI; Bu YINGGANG
Original assignee: Optoelectronics Co Ltd; Opticon Inc
Current assignee: Optoelectronics Co Ltd; Opticon Inc
Priority date: 2011-08-02
Filing date: 2011-08-02
Publication date: 2013-02-07
Anticipated expiration: 2014-02-02

Abstract

A barcode scanning module for a barcode reading device includes a light source for generating a beam of light, a first light collecting mirror having a first surface curvature, a second light collecting mirror having a second surface curvature, and a light receiving assembly for receiving light reflected by a barcode in response to being scanned by the beam of light generated by the light source. The first and second surface curvatures of the first and second light collecting mirrors, respectively, may be generally perpendicular to one another to direct the light reflected by the barcode at the light receiving assembly. The first optics assembly can also include a torsion bar assembly for allowing the first optics assembly to oscillate and vibrate to scan the barcode with the beam of light generated by the light source.

Description

MINIATURE BARCODE SCANNING MODULE FOR

A BARCODE READING DEVICE

FIELD

The present disclosure relates to devices for optically scanning images. More particularly, the present disclosure relates to a miniature barcode scanning module for an barcode reading device.

BACKGROUND

A barcode is an optical machine-readable label attached to an object, which directly or indirectly represents information about the object. Such information can include, without limitation, vendor identification, product name, price, patient name and other descriptive information about the object. Barcode reading devices are widely used in distribution, retail and many other industries for reading barcodes.

One common type of barcode reading device includes a barcode scanning module that a produces a laser light beam generated by a light source, such as laser diode. The barcode scanning module further includes a rotating or vibrating mirror arrangement that scans the light beam across the barcode. Light reflected by the barcode is condensed and received by a light receiving sensor of the module and is converted into an electrical signal representing the barcode. The electrical signal representing the barcode is decoded, and outputted as bar code read information.

The current trend is to reduce the size and weight of the barcode reading device to make it easier to use and less expensive to manufacture. This, in turn, requires the use of a dimensionally more compact light scanning module.

Accordingly, a miniaturized light scanning module is needed.

SUMMARY

Disclosed herein is a barcode scanning module for a barcode reading device. One or more embodiments of the barcode scanning module comprises a light source for generating a beam of light, a first light collecting mirror having a first surface curvature, a second light collecting mirror having a second surface curvature, and a light receiving assembly for receiving light reflected by a barcode in response to being scanned by the beam of light generated by the light source. The first and second surface curvatures of the first and second light collecting mirrors, respectively, may be generally perpendicular to one another to direct the light reflected by the barcode at the light receiving assembly.

The barcode scanning module, in one or more embodiments, further comprises a first light scanning mirror for scanning the barcode with the beam of light generated by the light source.

In one or more embodiments of the barcode scanning module, the first light scanning mirror and first light collecting mirror comprise a first optics assembly.

In one or more embodiments of the barcode scanning module, the first light scanning mirror is integrated or unitary with the first light collecting mirror.

In one or more embodiments of the barcode scanning module, the first optics assembly further comprises a holding member for holding the first light scanning and collecting mirrors, and a magnet for moving the holding member, the movement of the holding member moving the first scanning to mirror to scan the beam of light generated by the light source across the barcode, wherein the first light collecting mirror is disposed at an acute angle relative to the holding member.

The barcode scanning module, in one or more embodiments, further comprises a housing for holding the first optics assembly and wherein the first optics assembly further comprises a torsion bar fixedly connecting the holding member to the housing, the torsion bar allowing the holding member to move the first light scanning mirror to scan the barcode with the beam of light generated by the light source.

The barcode scanning module, in one or more embodiments, further comprises a second scanning mirror for reflecting the beam of light generated by the light source towards the first light scanning mirror.

In one or more embodiments of the barcode scanning module, the second scanning mirror and second collecting mirror comprise a second optics assembly.

In one or more embodiments of the barcode scanning module, the second scanning mirror is integrated or unitary with the second collecting mirror.

In one or more embodiments of the barcode scanning module, the second scanning mirror is disposed above or at an edge of the second light collecting mirror.

In one or more embodiments of the barcode scanning module, the first light collecting mirror reflects and concentrates the light reflected by the barcode onto the second light collecting mirror and the second light collecting mirror reflects and further concentrates the light reflected and concentrated by the first light collecting mirror onto an active area of the light receiving assembly, the further concentrated light reflected by the second light collecting mirror being entirely received by the active area of the light receiving assembly.

In one or more embodiments of the barcode scanning module, the light receiving assembly is disposed generally above the second light collecting mirror.

In one or more embodiments of the barcode scanning module, the first light collecting mirror reflects the light reflected by the barcode in a first direction onto the second light collecting mirror and the second light collecting mirror reflects the light reflected by the first light collecting mirror in a second direction onto the light receiving assembly.

The barcode scanning module, in one or more embodiments, further comprises a band pass filter for passing to the light receiving assembly only the light reflected by the barcode in response to the beam of light generated by the light source.

In some embodiments of the barcode scanning module, the band pass filter is integrated with the light receiving assembly.

The barcode scanning module, in some embodiments, further comprises a circuit board comprising one or more circuits for processing a signal output by the light receiving assembly, and a housing for holding the light source, the first and second light collecting mirrors, the light receiving assembly, and the circuit board. The light receiving assembly may be disposed on a surface of the circuit board facing a base surface of the housing.

In one or more embodiments of the barcode scanning module, the one or more circuits comprises an analog integrated circuit disposed adjacent to the light receiving assembly.

In one or more embodiments of the barcode scanning module, the light receiving assembly comprises a photodiode.

In one or more embodiments of the barcode scanning module, the first curvature of the first light collecting mirror is generally along a scanning direction.

The barcode scanning module, one or more embodiments, further comprises a housing for holding the light source the first and second light collecting mirrors, and the light receiving assembly, the housing including a base surface, the second collecting mirror being disposed at an acute angle relative to the base surface.

In one or more embodiments of the barcode scanning module, the light source comprises a laser diode.

The barcode scanning module, in one or more embodiments, further comprises a lens for collimating light emitted by the laser diode into the light beam. BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a miniature barcode scanning module for a barcode reading device, according to one or more embodiments of the present disclosure.

FIG. 2A is a perspective view of the module without the cover and the circuit board. FIG. 2 B is a perspective view of the module without the cover.

FIG. 2 C is a perspective view of the module without the cover and with the circuit board partially removed.

FIG. 3 A is an exploded perspective view of the light source according to one or more embodiments of the present disclosure.

FIG. 3B is an assembled perspective view of the light source according to one or more embodiments of the present disclosure.

FIG. 4A is an exploded perspective view of the first optics assembly according to one or more embodiments of the present disclosure.

FIG. 4B is an assembled perspective view of the first optics assembly according to one or more embodiments of the present disclosure.

FIG. 5A is perspective view of the second optics assembly according to one or more embodiments of the present disclosure.

FIG. 5B is perspective view of the second optics assembly according to one or more other embodiments of the present disclosure.

FIG. 5C is an elevational view of the second optics assembly of FIG. 5B.

FIG. 6A is an elevational view of the light receiving assembly according to one or more embodiments of the present disclosure.

FIG. 6B is an elevational view of the light receiving assembly according to one or more further embodiments of the present disclosure.

FIG. 7 is a perspective view showing the optical path to the light receiving assembly.

DETAILED DESCRIPTION

FIG. 1 is a perspective view of a miniature barcode scanning module for a barcode reading device, according the present disclosure. In one or more embodiments, the module, denoted generally by reference numeral 100, comprises a housing 102 with main and side compartments 103 a and 103b, respectively, (FIG. 2A) for holding and/or mounting optical and electrical components of the module 100 and a cover 114 for covering a circuit board 160 (FIG. 2B). The housing 102 includes a base wall 104, a front wall 106 (FIG. 2B), sides walls 108 and 1 10 and rear wall 112. The front wall 106 includes an opening or window 107 for emitting and receiving light.

In one or more embodiments, the module housing 102 and cover 114 are made of a metal that can be formed with sufficient accuracy and strength and to provide a sufficient electrical shielding for the electrical module components. In other embodiments, the metal can be a zinc alloy, such as ZDC2. In one or more other embodiments, aluminum, aluminum alloys, or magnesium alloys may be used. In embodiments where electrical shielding is effected separately, the module housing 102 and/or cover 1 14 may be formed of a resin such as reinforced plastic.

To reduce the dimensions and weight of the barcode reading device, the module housing 102 in one or more embodiments may have a length or depth D of 16 mm or less, a width W of 16 mm of less, and a height H (including the cover 114) of 8.0 mm or less. In other embodiments, the module housing 102 may have other dimensions.

FIGS. 2A-2C are perspective views of the module 100 with various components fully or partially removed to show the placement of the optical and electrical components in the module housing 102. As shown in FIG. 2A, the main compartment 103a of the module housing 102 holds and/or mounts a first light scanning and collecting optics assembly (first optics assembly) 130, a second light scanning and collecting optics assembly (second optics assembly) 140, and a driving coil 150. The side compartment 103b of the module housing 102 holds and/or mounts a light source 120.

As shown in FIG. 2B, a circuit board 160 covers the main compartment 103 a of the housing 102 and partially covers an upper portion of the side compartment 103b of module housing 102. The circuit board 160 includes a microprocessor 166 and an interface port 168 mounted on an exterior surface 162 of the circuit board 160. The cover 114 is disposed over the circuit board 160, but includes a cut-out 115, which allows access to the interface port 168 (FIG. 1).

As further shown in FIG. 2C, a light receiving assembly 170 and an analog large scale integrated circuit (LSI) 180 are mounted immediately adjacent to one another on an interior surface 164 of the circuit board 160.

FIGS. 3 A and 3B respectively are exploded and assembled perspective views of the light source 120. In one or more embodiments, the light source 120 comprises a laser diode 122 for generating a laser light beam, an aspherical lens arrangement 124 for collimating the laser light beam emitted by the laser diode 122, and a lens holder 126 coupled to the laser diode 122 for holding the lens arrangement 124 in axially alignment with a light emitting end 123 of the laser diode 122. The lens holder 126 includes an aperture 105 for emitting the light beam generated by the laser diode 122.

FIGS. 4A and 4B respectively are exploded and assembled perspective views of the first optics assembly 130. In one or more embodiments, the first optics assembly 130 comprises an elongated holding member 131, a first light collecting mirror 132, a first light scanning mirror 133, a permanent magnet 134, and a torsion bar assembly 136. The first light collecting mirror 132 is fixed at a first end of the holding member 131 and the magnet 134 is fixed at a second end thereof. The first light collecting mirror 132 is disposed at an acute angle 135 relative to the elongated holding member 131. In one or more embodiments, the acute angle 135 comprises, but is not limited to, a 45 degree angle. The first light collecting mirror 132 has a concave, cylindrically curved reflecting surface. The cylindrical curvature of the first light collecting mirror 132 is configured in the Y direction, perpendicular to the scanning direction (X-direction) of the module 100. The first light scanning mirror 133 is formed as a small planar section of the first light collecting mirror 131. The first light scanning mirror 133 can be made of metal, resin or glass, the first light collecting mirror 132 can be made of metal, resin or glass, and the holding member 131 can be made of resin. The torsion bar assembly 136 mounts the first optics assembly 130 to the base wall 104 of the housing 102 (FIG. 2A). The torsion bar assembly 136 comprises a torsion bar 137 having a mounting flange 137a formed at a first end thereof and a base 137b formed at a second end thereof. The mounting flange 137a fixedly connects the holding member 131 to the torsion bar assembly 136 and the base 137b fixedly connects the first optics assembly to an inner surface of the base wall 104 of the housing 102. The torsion bar 137 can have any suitable cross-sectional profile including, but not limited to, an I, H, V, T, and + cross-sectional profile. The torsion bar assembly 136 is made of an elastomeric material, such as silicone rubber, or any other suitable material with viscoelastic properties that allows torsion movement of the holding member 131 around axis A to allow oscillation or vibrational movement of the first optics assembly 130.

When reading a barcode of interest, the first optics assembly 130 moves in an oscillating or vibrational manner due a magnetic force generated between driving coil 150 and the permanent magnet 134, thereby causing the first light scanning mirror 133 to scan a beam of light generated by the light source 120 and reflected by the second optics assembly 140, across a barcode of interest. The configuration of the first light collecting mirror 132 allows it to collect incoming light reflected by the barcode and direct this light to the second optics assembly 140.

FIG. 5A is perspective view of the second optics assembly 140 according to one or more embodiments of the present disclosure. The second optics assembly 140 comprises a second light collecting mirror 142 and a second light scanning mirror 143 extending from a top edge or top surface portion of the second light collecting mirror 142. In one or more other embodiments, as shown in FIG. 5B, the second light scanning mirror extends 143' from a side edge of the second light collecting mirror 142'. The second light scanning mirror 143, 143' is generally perpendicular to the housing base wall 104 and generally parallel with the first light scanning mirror 132 of the first optics assembly 130 (FIG. 7). The second light scanning mirror 143, 143' of the second optics assembly 140, 140' bends the light beam generated by the light source 120 towards the first light scanning mirror 133 of the first optics assembly 130.

Referring still to FIGS. 5A and 5B, the second light collecting mirror 142, 142' has a concave, cylindrically curved reflecting surface which is generally is disposed at an acute angle 145 relative to the base wall 104 of the housing 102 (FIG. 5C) so that incoming light reflected by the first light collecting mirror 132 of the first optics assembly 130 changes direction upwardly towards the light receiving assembly 170 which is disposed generally over the second optics assembly 140, 140'. In one or more embodiments, the acute angle 145 comprises, but is not limited to, a 45 degree angle. The cylindrical curvature of the second light collecting mirror 142, 142 is configured in the X direction, perpendicular to the cylindrical curvature of the first light collecting mirror 132 of the first optics assembly 130. The second light scanning mirror 143, 143' can be made of metal, resin or glass and the second light collecting mirror 142, 142' can be made of metal, resin or glass.

FIG. 6A is an elevational view of the light receiving assembly 170 according to one or more embodiments of the present disclosure. The light receiving assembly 170 comprises a photo-sensitive sensor 172, such as an SMD (surface-mounted-device) photodiode, an uncolored transparent cover or package 176 made, for example, of plastic, disposed over the photo-sensor 172, and an external band pass filter 174 disposed in front of an active area of the photo-sensitive sensor 172 for permitting only the scanning light to pass through to the sensor 172 while blocking ambient light. The band pass of this filter can comprise a 650nm band pass, plus or minus about 50nm. In one or more embodiments, the external band pass filter 174 comprises a transparent glass coated with a band-pass film. In other embodiments, the external band pass filter 174 comprises a colored glass with an IR cutoff film where the colored glass has a color-blocking wavelength shorter than 600nm and where the IR cutoff film only permits wavelengths shorter than 700nm to pass through to the photo-sensitive sensor 172. To further reduce the size of the light receiving assembly 170, the bandpass filter 174 can be combined with the photo-sensitive sensor 172 by using a red colored package 176 and placing the IR cutoff filter 174 on the package 176 (not shown) to provide a total thickness of 1.8mm.

As shown in FIG. 6B, the light receiving assembly 170' according to one or more further embodiments comprises a photo-sensitive sensor 172' (e.g., a SMD photodiode), a band pass or IR cutoff filter 174' disposed on the active surface of the photo-sensitive sensor 172' and an uncolored package 176' (used with the band pass filter) or a red-colored package 176' (used with the IR cutoff filter) disposed over the sensor 172', to provide a total thickness less than 1.2mm.

FIG. 7 is a perspective view showing the optical path to the light receiving assembly 170. The first light collecting mirror 132 of the first optics assembly 130 reflects and concentrates the light Li, L2 reflected by the barcode in the Y direction onto the second light collecting mirror 142 of the second optics assembly 140 so that all the light in the Y direction can reach the relatively smaller area of the second light collecting mirror. The second light collecting mirror 142 of the second optics assembly 140 further concentrates and reflects the light L3, L₄ (received from the first light collecting mirror 132) in the X direction onto an active area of the light receiving assembly 170, which is located generally over the second optics assembly 140. This further concentrated light L3, L₄ is entirely received by the active area of the light receiving assembly 170.

While exemplary drawings and specific embodiments of the present disclosure have been described and illustrated, it is to be understood that that the scope of the invention as set forth in the claims is not to be limited to the particular embodiments discussed. Thus, the embodiments shall be regarded as illustrative rather than restrictive, and it should be understood that variations may be made in those embodiments by persons skilled in the art without departing from the scope of the invention as set forth in the claims that follow and their structural and functional equivalents.

Claims

CLAIMS What is claimed is:

1. A barcode scanning module for a barcode reading device, the barcode scanning module comprising:

a light source for generating a beam of light;

a first light collecting mirror having a first surface curvature;

a second light collecting mirror having a second surface curvature; and

a light receiving assembly for receiving light reflected by a barcode in response to being scanned by the beam of light generated by the light source;

wherein the first and second surface curvatures are generally perpendicular to one another to direct the light reflected by the barcode at the light receiving assembly.

2. The barcode scanning module of claim 1, further comprising a first light scanning mirror for scanning the barcode with the beam of light generated by the light source.

3. The barcode scanning module of claim 2, wherein the first light scanning mirror and first light collecting mirror comprise a first optics assembly.

4. The barcode scanning module of claim 3, wherein the first light scanning mirror is integrated or unitary with the first light collecting mirror.

5. The barcode scanning module of claim 3, wherein the first optics assembly further comprises:

a holding member for holding the first light scanning and collecting mirrors; and a magnet for moving the holding member, the movement of the holding member moving the first scanning to mirror to scan the beam of light generated by the light source across the barcode;

wherein the first light collecting mirror is disposed at an acute angle relative to the holding member.

6. The barcode scanning module of claim 5, further comprising a housing for holding the first optics assembly and wherein the first optics assembly further comprises a torsion bar fixedly connecting the holding member to the housing, the torsion bar allowing the holding member to move the first light scanning mirror to scan the barcode with the beam of light generated by the light source.

7. The barcode scanning module of claim 3, further comprising a second scanning mirror for reflecting the beam of light generated by the light source towards the first light scanning mirror.

8. The barcode scanning module of claim 7, wherein the second scanning mirror and second collecting mirror comprise a second optics assembly.

9. The barcode scanning module of claim 8, wherein the second scanning mirror is integrated or unitary with the second collecting mirror.

10. The barcode scanning module of claim 1, further comprising a scanning mirror for scanning the barcode with the beam of light generated by the light source, the scanning mirror and second collecting mirror comprise an optics assembly.

11. The barcode scanning module of claim 10, wherein the scanning mirror is integrated or unitary with the second collecting mirror.

12. The barcode scanning module of claim 10, wherein the scanning mirror is disposed above or at an edge of the second light collecting mirror.

13. The barcode scanning module of claim 1, wherein the first light collecting mirror reflects and concentrates the light reflected by the barcode onto the second light collecting mirror and the second light collecting mirror reflects and further concentrates the light reflected and concentrated by the first light collecting mirror onto an active area of the light receiving assembly, the further concentrated light reflected by the second light collecting mirror being entirely received by the active area of the light receiving assembly.

14. The barcode scanning module of claim 1, wherein the light receiving assembly is disposed generally above the second light collecting mirror.

15. The barcode scanning module of claim 14, wherein the first light collecting mirror reflects the light reflected by the barcode in a first direction onto the second light collecting mirror and the second light collecting mirror reflects the light reflected by the first light collecting mirror in a second direction onto the light receiving assembly.

16. The barcode scanning module of claim 1, further comprising a band pass filter for passing to the light receiving assembly only the light reflected by the barcode in response to the beam of light generated by the light source.

17. The barcode scanning module of claim 17, wherein the band pass filter is integrated with the light receiving assembly.

18. The barcode scanning module of claim 1, further comprising:

a circuit board comprising one or more circuits for processing a signal output by the light receiving assembly; and

a housing for holding the light source, the first and second light collecting mirrors, the light receiving assembly, and the circuit board;

wherein the light receiving assembly is disposed on a surface of the circuit board facing a base surface of the housing.

19. The barcode scanning module of claim 19, wherein the one or more circuits comprises an analog integrated circuit disposed adjacent to the light receiving assembly.

20. The barcode scanning module of claim 1, wherein the light receiving assembly comprises a photodiode.

21. The barcode scanning module of claim 1, wherein the first curvature of the first light collecting mirror is generally perpendicular to a scanning direction.

22. The barcode scanning module of claim 1, further comprising a housing for holding the light source, the first and second light collecting mirrors, and the light receiving assembly, the housing including a base surface, the second collecting mirror being disposed at an acute angle relative to the base surface.

23. The barcode scanning module of claim 1, wherein the light source comprises a laser diode.

24. The barcode scanning module of claim 23, further comprising a lens for collimating light emitted by the laser diode into the light beam.