JP4091359B2 - Two-dimensional code marking method and marking device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser marking device and a method surely reading a reading reference part. <P>SOLUTION: Laser is irradiated on the entire circumference of a data code 2 with the same width as that of a black cell so as to obtain a frame-shaped auxiliary background part 3. Out of the data part 22 of the data code 2, the black cells 22A adjoining the L-shaped reading reference part 21 comprise a part of the auxiliary background part 3 surrounding the entire circumference of the reading reference part 21. The black cells comprising the auxiliary background part 3 are disposed to such an extent as to be able to recognize the width and the length of the L-shaped reading reference part 21. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a two-dimensional code marking method and a marking device therefor.
[0002]
[Prior art]
A two-dimensional code is a combination of a plurality of white or black unit cells arranged in various arrangements in a rectangular matrix, and displays information. Compared to a one-dimensional code (for example, a so-called bar code), a lot of information is displayed. In recent years, production management and the like have been performed by marking a two-dimensional code on a product (object to be marked) with a laser marking device. For example, a data code (or data matrix) that is one of the two-dimensional codes is suitable for downsizing, and is often used particularly when the marking area is limited.
By the way, as shown in FIG. 7A, the data code 7 has a plurality of unit cells arranged in a matrix. Outer unit cells are blacked by marking the surface of the product, for example, by marking with laser light. It comprises an L-shaped reading reference portion 71 that has been changed in color and a rectangular data portion 72 that includes other unit cells. The reading reference portion 71 is formed to determine the data-like position and range.
[0003]
A code reader is used to read the data code 7. Specifically, after the entire data code 7 is captured as an image by the CCD scanner, the control device determines the brightness (black or white) of each unit cell, and “1” (black) or “0” ( White) is assigned to generate matrix data (matrix data). Then, the portion of the matrix data in which “1” is connected to the L-type is determined as the reading reference portion 71, the range of the data portion 72 is determined by the reading reference portion 71, and the data portion 72 is decoded. Thus, the information is read.
[0004]
[Problems to be solved by the invention]
Here, due to various factors, not all unit cells marked with laser light are sufficiently discolored to black, and some unit cells should be marked black because of insufficient heating. Nevertheless, it may become gray, for example. The data portion 72 has a data structure capable of error correction that can be correctly decoded even if the unit cell to be determined to be black is erroneously determined to be white even if the erroneous determination ratio is within a predetermined value. ing. Therefore, the occurrence of erroneous determination can be tolerated to some extent. However, if some of the unit cells constituting the reading reference unit 71 are also gray, “0” (white) is assigned to the unit cell, and the L-type reading reference unit 71 cannot be formed (FIG. 7B). reference). As a result, when the data code 7 is read, the reading reference part 71 is not discriminated, so that the data part 72 is not fixed and the decoding becomes impossible.
[0005]
The present invention has been completed based on the above circumstances, and an object of the present invention is to provide a marking method and a marking apparatus capable of reliably recognizing a reading reference portion when reading a two-dimensional code. There is to do.
[0006]
[Means for Solving the Problems]
As a means for achieving the above object, the invention of claim 1 is a method of marking a two-dimensional code formed by irradiating an object to be marked with laser light and arranging a plurality of unit cells in a rectangular matrix. In the two-dimensional code, a unit cell group serving as a reading reference portion is disposed at a predetermined position in the rectangular region, and a unit cell serving as a data portion is disposed in the other region. When the unit cell constituting the reading reference unit is not irradiated with laser, an auxiliary background portion that is irradiated with laser with at least the width of the unit cell is provided at least around the reading reference unit. It has the characteristics.
[0007]
The invention of claim 2 is a two-dimensional code marking device for marking a two-dimensional code formed by irradiating an object to be marked with laser light and arranging a plurality of unit cells in a rectangular matrix. A laser that emits the laser light in a case where a unit cell group serving as a reading reference unit is arranged at a predetermined position in the rectangular area and a unit cell serving as a data part is arranged in the other rectangular area. A light source, a laser irradiation control device for controlling the laser light emitted from the laser light source to irradiate the laser light onto the object to be marked, and control data for controlling the laser irradiation control device, Laser irradiation is not performed on the unit cells constituting the reading reference portion of the two-dimensional code, and at least the entire area around the reading reference portion is less than the unit cell width. Having the characteristics in the width was provided with a data generating means for generating control data as an auxiliary background portion subjected to the laser irradiation.
[0008]
[Action and effect of the invention]
The invention according to claim 1 and claim 2 is configured to mark the auxiliary background portion composed of unit cells that are irradiated with laser over the whole of the reading reference portion without performing laser irradiation on the reading reference portion. did.
When the object to be marked receives laser light, the object to be marked is heated or discolored by the laser light. Of the object to be marked, the reflectance is different between the portion irradiated with laser and the portion not irradiated with laser, so that the code reader can recognize both by the difference in brightness of reflected light.
In this way, in the conventional method of irradiating the reading reference portion with laser, if all unit cells constituting the reading reference portion are not sufficiently engraved, reading is impossible. Since the background color of the object to be marked is left without performing laser irradiation, the colors of the unit cells constituting the reading reference portion are not erroneously discriminated. In addition, since the reading reference portion is lifted by the surrounding auxiliary background portion, it can be reliably determined.
[0009]
Specifically, as shown in FIG. 8A, the reading reference unit 71 leaves the ground color of the object to be marked without marking with the laser beam. Then, the auxiliary background portion 73 disposed around the code data 7 (entirely around the reading reference portion 71) is marked with a laser beam, for example, black and formed. When the data code 7 is read by the code reader, “1” is assigned to the black unit cell, “0” is assigned to the white unit cell, and matrix data (matrix data) is generated. The
[0010]
Then, an L-shaped region in which four “0” s are continuously arranged in a straight line and four “0” s are arranged in a straight line from one end side of “0” that is linearly connected to the reading reference unit 71. What is necessary is just to discriminate. Further, the auxiliary background portion 73 functions as a background for making the L-shaped region (reading reference portion 71) formed with “0” on the matrix data stand out.
Here, the term “auxiliary background portion that has been irradiated with laser with a width equal to or larger than the unit cell width around the reading reference portion” in the claims refers to a unit cell (dashed line A) that constitutes the auxiliary background portion 73. It is not necessary that all the unit cells) are printed in black, but may be formed so that the width and length of the reading reference portion 71 can be recognized. Further, a part of the data part 72 (unit cell with a broken line A) may also serve as the auxiliary background part 73.
[0011]
Therefore, even if some of the unit cells constituting the auxiliary background portion 73 are not determined to be black but are erroneously determined to be white, the white unit cells are arranged in an L shape. The reading reference section 71 is not affected and can be reliably determined (see FIG. 8B).
[0012]
DETAILED DESCRIPTION OF THE INVENTION
<First Embodiment>
Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 6.
The laser marking apparatus according to the present embodiment is used for marking a work W with a data code 2 in which, for example, a total of 16 unit cells in four columns in each of vertical and horizontal directions are arranged in a rectangular matrix. In the present embodiment, the ground color of the workpiece W is white for convenience of explanation.
[0013]
As shown in FIGS. 1 and 2, the laser marking device according to the present embodiment includes a laser light source 10, a galvanometer scanner 11 and a controller 12 corresponding to a laser irradiation control device, and a laser signal according to a control signal from the controller 12. The laser light emitted from the light source 10 is scanned to a desired position on the workpiece W by the galvanometer scanner 11.
[0014]
In this embodiment, the unit cell constituting the data code 2 is one in which the surface of the workpiece W is changed to black by irradiating laser light (hereinafter referred to as “black cell”), and without irradiating the laser light. The work W is composed of two types: the ground color (white) of the workpiece W (hereinafter referred to as “white cell”). Various data codes 2 are configured by combining these two types of unit cells, and all the data codes 2 have a reading reference unit 21. The reading reference unit 21 is composed of a total of seven white cells connected in an L shape that form the two outer sides of the data code 2. The other unit cell groups constitute the data unit 22 (see FIG. 3).
[0015]
In order to mark these data codes 2, the controller 12 stores a memory 12A in which matrix data corresponding to various data codes 2 is stored, and marking data (“laser” based on the matrix data read from the memory 12A. CPU 12 </ b> B is generated that corresponds to “control data for controlling the irradiation control device”. As shown in FIG. 3, the matrix data is, for example, arranged in a matrix by assigning “1” to a black cell of data code 2 and assigning “0” to a white cell. Further, in this embodiment, the value “1” is input in advance to the reading reference unit 21 as in the past, and among the unit cells constituting the data unit 22, a predetermined value adjacent to the reading reference unit 21 is set. “0” is input to the unit cell.
[0016]
And in this embodiment, when marking each data code 2, as shown in FIG.5 and FIG.6, laser irradiation with the same width | variety as a black cell is performed to the perimeter of the data code 2 of 4 rows 4 columns. A frame-shaped auxiliary background portion 3 is provided. Therefore, when the CPU 12B generates the marking data, it also generates marking data for generating the auxiliary background portion 3. Further, in the data portion 22 of the data code 2, the black cell 22A adjacent to the L-type reading reference portion 21 constitutes a part of the auxiliary background portion 3 that surrounds the reading reference portion 21 over the entire circumference. Note that the black cells constituting the auxiliary background portion 3 do not need to be continuously formed around the entire L-shaped reading reference portion 21, so that the width and length of the reading reference portion 21 can be recognized. Just place it.
[0017]
Next, the operation of this embodiment will be described.
When a marking command is given to the controller 12, the CPU 12B reads matrix data from the memory 12A and inverts values assigned to all unit cells (see FIG. 4). Then, from this matrix data, marking data for designating coordinates to be irradiated with laser light on the workpiece W and ON / OFF of the laser light source is generated, and at the same time, laser irradiation is performed around the entire data code 2. Marking data for marking the auxiliary background portion 3 composed of cells is also generated. Then, the data code 2 is marked on the workpiece W by transmitting the marking data to the laser light source 10 and the galvanometer scanner 11.
[0018]
Thereby, in the data code 2, the region irradiated with the laser light is a black cell, and the region not irradiated is a white cell. Accordingly, as shown in FIG. 5, the reading reference portion 21 remains white as the ground color of the work W, and the auxiliary background portion 3 is printed in black over the entire area around the data code 2.
[0019]
By the way, the data code 2 is read by a code reader. As a principle, first, the entire data code 7 is captured as an image by a CCD scanner, and then black or white is applied to each pixel of the CCD. Judgment is made and “1” (black) or “0” (white) is assigned. At this time, scanning is performed in the horizontal direction, the number of pixels having “1” or “0” is counted, and subsequently, scanning is performed in the vertical direction. Count the number of Thereafter, the smallest number of pixels having the same numerical value is defined as one side of the unit cell. Based on this, a unit cell is formed from each pixel, and if the value assigned to each pixel constituting the unit cell is “1” equal to or greater than a predetermined ratio, “1” is assigned. 0 "is assigned to generate matrix data (matrix data).
[0020]
From this matrix data, four “0” s are linearly continued, and an L-shaped region where four “0” s are linearly connected from one end side of “0” linearly connected (reading reference). Part 21) is identified from the whole. At the time of identification, the reading reference portion 21 made up of white cells (value “0”) is entirely surrounded by black cells (value “1”). Can be accurately identified. In addition, it is unlikely that the white cell portion is erroneously recognized as a black cell (value “1”). Further, even if some of the black cells constituting the auxiliary background portion 3 are erroneously recognized as white cells (value “0”), the width and length of the white cells constituting the reading reference portion 21 are identified. Since there is no problem, the reading reference portion 21 can be reliably identified.
[0021]
As described above, according to the present embodiment, since the reading reference unit 21 does not perform the marking process and leaves the white color that is the ground color of the workpiece W, each unit cell constituting the work W There is no misclassification as black, and it is definitely discriminated as white. Therefore, when the data code 2 is read, the reading reference portion 21 can be reliably determined (see FIG. 6).
In addition, there is a concern that the marking around the data code 2 may increase the size of the conventional data code. However, even in the conventional data code, in order to determine the reading reference portion, a frame-like region (margin) that is not marked is left around, and in this embodiment, the auxiliary background portion is added to this frame-like region. 3 was formed. Therefore, the space required for printing the data code 2 on the work W is the same between the conventional data code and the data code 2 of the present embodiment, and the space does not increase.
[0022]
<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention, and further, within the scope not departing from the gist of the invention other than the following. Various modifications can be made.
(1) In the above embodiment, the matrix data in which the reading reference portion 21 of the data code 2 is previously set to a value of “1” is stored in the memory 12A, and this is inverted at the time of marking. Matrix data replaced with a value of “0” in advance may be stored. In other words, the white and black colors of the data code 2 are all reversed. However, the present invention is not limited to this, and any configuration is acceptable as long as the reading reference portion is white. The data portion 22 may not be reversed.
[0023]
(2) In the above embodiment, the auxiliary background portion 3 is configured as an aggregate of black cells, but is not limited thereto, and is configured by an L-shaped region that is continuously irradiated with laser light with a width equal to or greater than the width of the unit cell. You may do it.
[0024]
(3) In the above embodiment, the auxiliary background portion 3 is formed so that a part of the auxiliary background portion 3 surrounds the four sides of the data code 2. May be arranged in an L shape. Also in this case, the auxiliary background portion may be formed in a part of the data portion so as to cover the entire L-type reading reference portion.
[0025]
(4) In the above embodiment, an example in which a black cell is formed by irradiating a workpiece W having a white ground color with a laser beam is described. However, a laser beam is irradiated to a workpiece having a black ground color (or dark color). Then, the color may be changed to white (or light color). In this case as well, the reading reference portion may be irradiated with the laser light without irradiating the auxiliary background portion with the laser light.
[0026]
(5) In the above embodiment, an example of a data matrix is shown as a two-dimensional code. However, the present invention is not limited to this, and the present invention can also be applied to a two-dimensional code such as a QR code.
[0027]
(6) In the present embodiment, an example of galvano scanning has been described. However, for example, the present invention can also be applied to a mask type laser marking apparatus that selectively irradiates laser light through a mask.
[Brief description of the drawings]
FIG. 1 is an overall view of a laser marking device of the present embodiment. FIG. 2 is a block diagram of the laser marking device. FIG. 3 is a diagram schematically showing code data and matrix data corresponding to the code data. Fig. 5 is a diagram schematically showing the matrix data corresponding to the code data. Fig. 5 is a diagram schematically showing the code data and the corresponding matrix data. Fig. 6 is a schematic diagram showing the code data and the corresponding matrix data. FIG. 7 is a diagram schematically showing conventional code data and matrix data corresponding thereto. FIG. 8 is a diagram schematically showing the data code of the present invention and matrix data corresponding thereto. Explanation of symbols]
2 ... Data code 3 ... Auxiliary background 10 ... Laser light source 11 ... Galvanometer scanner 12A ... Memory 12B ... CPU
21 ... Reading reference part 22 ... Data part 22A ... Black cell

Claims (2)

A method for marking a two-dimensional code formed by irradiating an object to be marked with laser light and arranging a plurality of unit cells in a rectangular matrix, wherein the two-dimensional code is a predetermined one of the rectangular regions. In a unit cell group serving as a reading reference part at a position and a unit cell serving as a data part in other areas,
The unit cell constituting the reading reference portion is not irradiated with laser, but at least the reading reference portion is provided with an auxiliary background portion that is irradiated with laser at a width equal to or larger than the unit cell width. A method for marking a two-dimensional code, characterized in that A marking device for a two-dimensional code that marks a two-dimensional code formed by irradiating an object to be marked with laser light and arranging a plurality of unit cells in a rectangular matrix, wherein the two-dimensional code is the rectangular region In which a unit cell group serving as a reading reference portion is arranged at a predetermined position and a unit cell serving as a data portion is arranged in the other region,
A laser light source for emitting the laser light;
A laser irradiation control device that controls the laser light emitted from the laser light source to irradiate the laser light onto the object to be marked;
Control data for controlling the laser irradiation control device, wherein the unit cell constituting the reading reference portion of the two-dimensional code is not irradiated with laser, and at least the reading reference portion is entirely covered by the unit. A two-dimensional code marking device comprising: data generation means for generating control data for providing an auxiliary background portion that has been irradiated with laser with a width equal to or greater than the cell width.

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