JPH11232409A - Two-dimensional bar code forming device and reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To freely and quickly change a two-dimensional bar code by means of an optical element such as a 'DMD(R)'. SOLUTION: For instance, the DMD 20 is provided on the surface of a bucket 15 which is used in an automatic warehouse. The DMD 20 has areas 20a which are divided in a (4×4) matrix, for example, and these two-dimensional bar code forms the areas 20a. Each of areas 20a consists of a micro mirror and the inclination of the micromirror is controlled by a DMD drive circuit 31. The light irradiated from a light source 33 is reflected on the micromirror of each area 20a and received by a CDD 34. Then the two-dimensional bar code is decoded by a control circuit 36.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-dimensional bar code for displaying information by a lattice-shaped pattern, and more particularly to a device for forming a two-dimensional bar code and a device for reading a two-dimensional bar code.

[0002]

2. Description of the Related Art A two-dimensional barcode is constituted by assigning 1-bit information by painting each area partitioned in a grid pattern with black or white. For example, in the case of a 2 × 2 matrix, 16 types are available. Can be displayed. Conventionally, two-dimensional barcodes are printed on paper, and are attached to the surface of a bucket, for example, in an automatic warehouse, to indicate information corresponding to the number and contents of conveyed objects stored in pallets and buckets. You. Such a two-dimensional barcode is read by a reading device and decoded by a computer, and in a system such as an automatic warehouse, the transported object is managed based on the decoding result.

On the other hand, in recent years, DMD (trade name; digital
Abbreviation for micromirror device. ) Has been developed. The DMD is configured by two-dimensionally arranging a large number of micromirrors each having a side of about 16 μm in a lattice shape. Each micromirror can be tilted in two directions, and the tilt direction is changed by an electrostatic field effect of a memory element provided immediately below each micromirror. That is, assuming that the micromirror receiving the electrostatic force is tilted in the first tilt direction, the micromirror not receiving the electrostatic force tilts in the second tilt direction.

[0004]

The printed two-dimensional bar code corresponds to a single piece of information. For example, in the case of an automatic warehouse, when the contents of a conveyed object stored in a bucket or the like are changed, It is necessary to newly attach a paper on which a two-dimensional barcode is printed according to the content of the change. Also 2
Each time the code pattern of the dimensional barcode changes,
Replacing a label on which a two-dimensional barcode is printed is extremely complicated, and an old two-dimensional barcode is placed around a new label.
If a part of the label on which the three-dimensional barcode is printed remains, the reading device cannot read the barcode,
There was a problem of decoding to incorrect information.

An object of the present invention is to provide a two-dimensional barcode forming apparatus that can freely and quickly change a two-dimensional barcode using an optical element such as a DMD.

[0006]

A two-dimensional bar code forming apparatus according to the present invention comprises a plurality of light deflecting elements capable of selectively setting an ON state for deflecting incident light in a predetermined direction and an OFF state for not deflecting the incident light. Thus, a two-dimensional barcode is formed.

The two-dimensional bar code forming apparatus preferably includes a deflection control means for controlling the on / off state of each of the plurality of light deflecting elements to change the two-dimensional bar code. Further, the two-dimensional barcode forming apparatus may include storage means for storing data corresponding to a plurality of two-dimensional barcodes.
One is selected, and the on / off state of the plurality of light deflection elements is controlled based on the selected data.

The light deflecting element is, for example, a mirror element which is set to an on state or an off state by changing an inclination angle by electrostatic force. Alternatively, the light deflecting element is
This is a diffractive light modulation element that is set to an on state or an off state by a light diffraction action.

A two-dimensional bar code reader according to the present invention comprises a light source and a plurality of light deflection units capable of selectively setting an ON state for deflecting incident light from the light source in a predetermined direction and an OFF state for not deflecting the light. And a light deflecting means for forming a two-dimensional barcode by these light deflecting elements, and controlling the on / off state of the plurality of light deflecting elements to change the two-dimensional barcode formed by the light deflecting elements. And a light receiving means for receiving the light reflected by the light deflecting means and detecting a two-dimensional bar code.

The optical axis of the light source and the optical axis of the light receiving means are preferably located substantially at the center of the light deflecting means, and are preferably symmetric with respect to the normal to the plane of the light deflecting element in the ON state.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an overhead traveling vehicle provided in an automatic warehouse, and a bucket carried by the traveling vehicle is provided with a two-dimensional barcode forming apparatus according to the first embodiment of the present invention.

The main body 11 of the overhead traveling vehicle 10 can travel along a rail 12 provided on the ceiling of the automatic warehouse.
The main body 11 is provided with four belts 13 extending downward, and an elevating table 14 is attached to the end of the belt 13. The upper end of each belt 13 is connected to a winding mechanism provided in the main body 11, and by driving the winding mechanism, the lifting platform 14 moves up and down.

The lift 14 is provided with a clamp 16 for holding a bucket 15, and the clamp 16 can be opened and closed by a drive mechanism (not shown) provided in the lift 14. That is, the overhead traveling vehicle 10 stops immediately above the bucket 15 in a state in which nothing is transported, and the elevator 14 releases the clamp 16 and descends to the vicinity of the bucket 15. Then, the clamp 16 is closed and the lift 14 is raised, so that the bucket 15 is lifted. In this state, the overhead traveling vehicle 10 travels and the bucket 15
Is transported to a predetermined position.

An object to be transported is stored in the bucket 15. The bucket 15 is provided with a DMD 20, a switch 18, and a liquid crystal display device 19. The DMD 20 forms a two-dimensional barcode of, for example, a 4 × 4 matrix, and the two-dimensional barcode corresponds to information indicating the contents and the number of objects to be conveyed, the storage location of the bucket 15, and the like. D
The two-dimensional barcode formed by the MD 20 can be changed by operating the switch 18. On the liquid crystal display device 19, characters or symbols corresponding to the two-dimensional bar code determined by the switch 18 are displayed.

The traveling of the overhead traveling vehicle 10 and the operation of the elevator 14 are controlled by a control system (not shown) provided in the automatic warehouse. That is, the control system recognizes the destination of the overhead traveling vehicle 10 and the storage location of the transported bucket 15 based on the data read and decoded by a reading device described later, and the bucket 15 is transported to that location. You.

FIG. 2 is provided at a predetermined place in an automatic warehouse,
FIG. 2 is a block diagram illustrating a schematic configuration of an apparatus for reading a two-dimensional barcode formed by a DMD 20.

In FIG. 1, the DMD 20 has areas 20a divided into a 4.times.4 matrix.
0a forms a two-dimensional barcode. Each area 20
a is provided with a number of micromirrors (not shown),
These micromirrors are arranged, for example, in a grid on the same plane. The tilt angle of the micro mirror included in each area 20a is changed by the control of the DMD drive circuit 31. That is, the micromirrors in one region 20a are all inclined in the same direction by the same magnitude.

The DMD drive circuit 31 is controlled by a control circuit (CPU) 37 having a microcomputer. In addition to the DMD drive circuit 31, the control circuit 37 is connected to an EEPROM 38, which is a rewritable nonvolatile memory, a switch 18, and a liquid crystal display (LCD) 19.

The EEPROM 38 stores a plurality of code data which can be set by the switch 18, display data corresponding to each code data, that is, information displayed by the liquid crystal display device 19, and data for driving the DMD drive circuit 31. And are stored respectively. Writing and reading of data to and from the EEPROM 38 are performed by the control circuit 37. That is, by operating the switch 18, under the control of the control circuit 37, predetermined code data is selected from a plurality of code data stored in the EEPROM 38, and display data corresponding to the selected code data is read. And is displayed by the liquid crystal display device 19. Further, the DMD drive circuit 31 is controlled by the control circuit 37, whereby a display pattern corresponding to the selected code data is formed by the DMD 20.

The switch 18 is a push button type.
Each time the switch is pressed once, one of a plurality of code data stored in the EEPROM 38 is selected in a predetermined order, and after the last code data is selected, if the switch 18 is further pressed, the operation returns to the first code data.

The two-dimensional bar code reader 32 is provided at a predetermined position in the warehouse. That is, at this position, when the DMD 20 of the bucket 15 is set to the position facing the two-dimensional barcode reader 32 by the raising / lowering operation of the lift 14, the two-dimensional barcode formed by the DMD 20 can be read.

The two-dimensional bar code reader 32 includes a light source 33
And a CCD (solid-state imaging device) 34, a CCD drive circuit 35, and a control circuit 36. The light source 33 and the CCD 34
In a state where D20 is set at a predetermined position, the light source 3
3 illuminates the DMD 20 and reflects the light.
4 so as to be able to receive light. On the other hand, D
The tilt direction of the micromirror provided on the MD 20 is one of a first tilt direction in which the light emitted from the light source 33 is reflected (deflected) to the CCD 34 and a second tilt direction in which the light is reflected in a direction different from the CCD 34. Is set to

The CCD 34 is driven by a CCD driving circuit 35, whereby an image formed by the reflected light from the DMD 20 is detected. This image is input to a control circuit 36 having a microcomputer, and is subjected to predetermined processing.

In the DMD 20 shown in FIG. 2, a white area 20a indicates that the micromirror is in the on state in which the micromirror is inclined in the first inclination direction, and a hatched area 20a indicates that the micromirror is in the second state. In the off state inclined in the inclination direction. That is, each area 2
A two-dimensional bar code is formed by the on / off state of the micromirror 0a.
Is determined by operating. EEPROM 38 has
Data corresponding to a plurality of two-dimensional barcodes is stored in advance, and one data is selected by operating the switch 18, and the on / off state of the micromirror in each area 20a is controlled based on this.

FIG. 3 is a diagram conceptually showing a configuration for driving a micro mirror (light deflecting element) 21 provided in the DMD 20.

The micromirror 21 is a substantially rectangular plate-like member, and has a mirror surface formed by laminating an aluminum thin film on the surface thereof. One side of the micro mirror 21 is, for example, about 16 μm. The two corners 21 a and 21 b on the diagonal line of the micro mirror 21 are
Are connected via a torsion hinge 24 made of an elastic material. That is, the micro mirror 21 is rotatable around the torsion hinge 24, and stably stops at a position where one of the two corners 21 c and 21 d different from the corners 21 a and 21 b is in contact with the silicon substrate 22.

A plurality of electrodes 25 (memory elements) are formed on the surface of the silicon substrate 22 on the side of the micro mirror 21. When a voltage is applied to a predetermined one of these electrodes 25, an electrostatic force acts on the micromirror 21, and the micromirror 21 is tilted in the first tilt direction when the corner 21c contacts the silicon substrate 22. (ON state). On the other hand, when no electrostatic force is applied, the micromirror 21 is tilted in the second tilt direction by the torsion elastic force of the torsion hinge 24 such that the corner 21d contacts the silicon substrate 22 (off state). .

Referring to FIG. 2 and FIG.
The reflection of light incident on 1 will be described. The light source 33 is
For example, a parallel light flux composed of a light-emitting diode and a collimator lens is emitted, and the emitted light flux is positioned substantially at the center of the DMD 20 and has a predetermined angle with respect to a normal line V of the micromirror inclined in the first direction. It is arranged to enter at an angle θ. An imaging lens is provided in front of the CCD 34, and the imaging lens is arranged so that its optical axis is symmetric with respect to the normal line V with the optical axis of the collimator lens of the light source 33. That is, when the micromirror is tilted in the first direction, the light source 33 and the CCD 34
Are arranged so that the amount of received light is maximized, whereby the micromirror inclined in the first direction can be accurately detected.

When the micro mirror 21 is in the ON state,
As shown by the solid line L1, it is rotationally displaced clockwise by + 10 °, and when in the off state, it is rotationally displaced counterclockwise by −10 ° as shown by the broken line L2. When in the ON state, the light source 3
3 (see FIG. 2) is emitted from the micro mirror 21
And is incident on the CCD 34 (see FIG. 2) (reference B1). On the other hand, when the light source 33 is in the off state,
Is reflected from the micromirror 21 and does not enter the CCD 34 (reference B2). That is, the micromirror 21 can be selectively set between an on state in which incident light is reflected by the CCD 34 and an off state in which incident light is not reflected on the CCD 34 side.

As described above, a two-dimensional bar code is formed by the inclined state of the micro mirror 21, that is, the on / off state, and when the DMD 20 is placed at a position facing the two-dimensional bar code reader 32, the light is radiated from the light source 33 and given a predetermined value. The light reflected on the area 20a is received by the CCD 34, whereby a two-dimensional barcode image is detected. This image is subjected to predetermined processing in the control circuit 36, whereby information indicated by the two-dimensional bar code is decoded.

As described above, according to the first embodiment, the two-dimensional bar code can be quickly changed by changing the tilt direction of the micro mirror 21 in each area 20a of the DMD 20 by operating the switch 18. Can be. Therefore, when it is necessary to change the two-dimensional barcode, for example, when the number of conveyed objects in the bucket 15 changes, the change can be made immediately, and the operation is simple.

Although the above embodiment is an example in which the present invention is applied to an automatic warehouse, the present invention is not limited to this, and can be applied to an automatic assembling system having an assembling robot and the like. In such a case, in a certain process, the information of the own process is added to the two-dimensional barcode corresponding to the information in the process upstream therefrom by operating the switch 18, and the two-dimensional barcode is attached. The transferred object can be sent to a downstream process.

FIGS. 5 and 6 show a diffractive light modulating element 40 provided in the second embodiment. In this embodiment, the light used for forming the pattern is monochromatic light, for example, infrared light. Diffractive light modulation element 40
Are provided in place of the micro mirror 21 (see FIG. 3), and the other configuration is the same as that of the first embodiment.

The diffractive light modulating element 40 includes a large number of beam members 41.
Having. The beam member 41 is made of, for example, silicon nitride, and is a thin plate-shaped member having a width of 1.0 to 1.5 μm and a length of 15 to 120 μm. The surface of the beam member 41 is coated with, for example, a thin film 42 of aluminum to form a mirror surface. Both ends of each beam member 41 are supported by spacers 44 fixed on a substrate 43. The spacer 44 is made of, for example, silicon dioxide. Each beam member 41 is disposed in parallel with each other, and the interval between adjacent beam members 41 is
It is substantially equal to the width of the beam member 41.

The distance between the front surface of the beam member 41 (ie, the back surface of the thin film 42) and the front surface of the substrate 43 is １ ／ of the wavelength (λ) of the light applied to the diffractive light modulation element 40. . The plate thickness of the beam member 41 is の of the wavelength.

When no voltage is applied between the beam member 41 and the substrate 43, the beam member 41 is parallel to the substrate 43, as shown in FIGS. Are separated by λ / 2. In this state,
The monochromatic light having the wavelength λ applied to the substrate 43 is reflected by the diffraction action (on state). On the other hand, when a voltage is applied between the beam member 41 and the substrate 43, as shown in FIGS. 7 and 8, the beam member 41 bends so that its back surface is in close contact with the substrate 43, and The distance between the surface of 41 and the substrate 43 is λ / 4. In this state, the substrate 4
The incident light and the reflected light with respect to 3 cancel each other, and there is no reflected light (off state).

As described above, in the second embodiment, since the diffractive light modulation element 40 which is set to the on state or the off state by the diffraction of light is used, except that the incident light must be monochromatic light. Therefore, the operation is the same as that of the first embodiment, and an equivalent effect is obtained.

[0038]

As described above, according to the present invention, for example, D
The two-dimensional barcode can be freely and quickly changed using an optical element such as an MD.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an overhead traveling vehicle having a two-dimensional barcode forming device according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a schematic configuration of an apparatus for reading a two-dimensional barcode formed by a DMD.

FIG. 3 is a diagram conceptually showing a configuration for driving a micromirror.

FIG. 4 is a diagram illustrating a reflection state of light incident on a micromirror.

FIG. 5 is a cross-sectional view showing a diffractive light modulation element provided in the second embodiment and in an ON state, cut along a plane perpendicular to a beam member.

6 is a side view of the diffractive light modulation device shown in FIG.

FIG. 7 is a cross-sectional view showing the diffractive light modulation element in an off state by cutting along a plane perpendicular to a beam member.

8 is a side view of the diffractive light modulation device shown in FIG.

[Explanation of symbols]

 Reference Signs List 20 DMD (light deflecting means) 20a area 21 Micromirror (light deflecting element) 32 Two-dimensional barcode reader 33 Light source 40 Diffractive light modulating element (light deflecting element)

Continuing from the front page (72) Inventor Takaaki Yoshinari 2-36-9 Maeno-cho, Itabashi-ku, Tokyo Asahi Gaku Kogyo Co., Ltd. (72) Inventor Kiyoshi Negishi 2-36-9 Maeno-cho, Itabashi-ku, Tokyo Manabu Asahi Industrial Co., Ltd.

Claims (7)

[Claims] 1. A two-dimensional bar code, wherein a two-dimensional bar code is formed by a plurality of light deflecting elements capable of selectively setting an ON state for deflecting incident light in a predetermined direction and an OFF state for not deflecting the incident light. Code forming device. 2. The two-dimensional barcode forming apparatus according to claim 1, further comprising a deflection control unit that controls the on / off state of each of the plurality of light deflection elements to change the two-dimensional barcode. apparatus. 3. A storage unit for storing data corresponding to a plurality of two-dimensional barcodes, wherein the deflection control unit selects one of the data, and stores the data of the plurality of light deflection elements based on the selected data. The two-dimensional barcode forming apparatus according to claim 2, wherein the on / off state is controlled. 4. The two-dimensional barcode forming apparatus according to claim 1, wherein the light deflecting element is a mirror element that is set to an on state or an off state by changing an inclination angle by an electrostatic force. 5. The two-dimensional barcode forming apparatus according to claim 1, wherein the light deflecting element is a diffractive light modulation element that is set to an on state or an off state by a diffraction effect of light. 6. A light source, and a plurality of light deflecting elements capable of selectively setting an ON state for deflecting incident light from the light source in a predetermined direction and an OFF state for not deflecting the light, and these light deflecting elements 2. A two-dimensional bar code reading apparatus, comprising: a light deflecting unit that forms a two-dimensional bar code by using the light deflecting unit; 7. The optical axis of the light source and the optical axis of the light receiving means are located substantially at the center of the light deflecting means, and are symmetric with respect to the normal to the plane of the light deflecting element in the ON state. 7. The two-dimensional barcode reader according to claim 6, wherein: