JP2002361444A - Laser marking device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser marking device with which marking information can be printed without a variation in depth of printing. SOLUTION: For such a line segment element as a line segment element L11 which is not divisible by the length of a reference distance interval d10 and yields a fraction of distance, a plurality of coordinate data at every reference distance interval d10 are generated from the start point S to the short of the terminal point E of the line segment, every coordinate datum of points from the start point S through the short point of the terminal point E is successively given to a galavanoscanner 20 at every time interval t. Thus, the printing is performed at a marking speed equal to that for a line segment element L10 which is divisible by the length of the reference distance interval d10 and the variation in the depth of printing is not generated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a galvano scanning type laser marking apparatus provided with a galvano scanner for scanning an irradiation point on an object to be marked by changing the direction of a laser beam from a laser light source.

[0002]

2. Description of the Related Art A laser marking apparatus of this type includes a laser light source for emitting laser light, a galvano scanner for changing the direction of the laser light and scanning an irradiation point of the laser light on an object to be marked, and a printer for printing. And control means for driving and controlling the laser light source and the galvano scanner based on marking information such as characters, symbols, and figures to be formed. The control means divides the set marking information into various line segment elements, and for each of those line segment elements, a plurality of coordinate data including a start point and an end point constituting the line segment element,
It is sequentially generated for each distance interval corrected according to the length of the line segment element. More specifically, the control means is set in advance with a reference distance interval d1 (for example, a length of one half of the spot diameter at the irradiation point; a dotted circle in FIGS. 4 and 5 indicates a spot outline). And the length is L1 (=
For the line segment element of (d1 × 5), as shown in FIG. 4A, a plurality of coordinate data are generated for each reference distance interval d1 from the start point S to the end point E.

On the other hand, if the length is L2 (= d1 × 5 + qq (<
d1) is the remainder length when the line segment element L2 is divided by the reference distance interval d1. (B), (C), for example, the reference distance interval d1 is corrected to d2 (= d1 + (q / 5)) as shown in FIGS. , And generates coordinate data for each corrected distance interval d2. Then, coordinate data for each distance interval according to the length of each line segment element is sequentially given to the galvano scanner at a predetermined timing, and the galvano scanner is driven sequentially according to the positional deviation of each coordinate data.

[0004]

However, in the conventional laser marking apparatus, in the above-described correction processing of the distance interval between the respective coordinate data, the timing at which the respective coordinate data is given to the galvano scanner also depends on the light intensity of the laser light source. Is also always constant without being changed. For example, the line segment element L1
Are sequentially given to the galvano scanner at a time interval t (= d / V) calculated from the preset marking speed V and the reference distance interval d1, for example. I do. On the other hand, the coordinate data for each distance interval d2 generated for the line segment element L2 is also provided to the galvano scanner at the time interval t.

Accordingly, with respect to the line segment element L1, the irradiation point of the laser beam is scanned at a distance interval d1 at every time interval t, and printing is performed at a speed V1 (= d1 / t). On the other hand, in the line segment element L2, the irradiation point of the laser beam is scanned at a time interval t at a distance interval d2, and is printed at a speed V2 (= d2 / t). That is,
The conventional laser marking device, for each line segment element,
The coordinate data at distance intervals according to the length of each line segment element is generated, and these coordinate data are given to the galvano scanner at a fixed timing, so that the printing speed changes accordingly, and as a result the unit There is a problem in that the irradiation amount per area changes, and as a whole marking information, the printing depth varies for each of the line segment elements constituting the marking information.

Further, as shown in FIG. 5, a line segment element L3 (= d1.times.x) where the fraction distance q3 is slightly smaller than the reference distance d1.
4 + q3), and the following correction processing is performed on the two line segment elements L4 (= d1 × 4 + q4) having slightly different lengths as a whole, with the fraction distance q4 being slightly larger than the reference distance interval d1. I was In the line segment element L3, the fraction distance q3 is equally distributed to four data intervals from the start point to the fourth coordinate data, and the distance interval d3 (= d1 +
(Q3 / 4)) coordinate data is generated. On the other hand, in the line segment element L4, the length obtained by subtracting the fractional distance q4 from the distance interval d1 (= d1 -q4) is subtracted by q4 / 5 from each of the five data intervals from the start point to the fifth coordinate data. The coordinate data is generated for each of the distance intervals d4 (= d1-(q4 / 5)). With such a configuration, the printing speed changes in accordance with the distance interval of the coordinate data even for two line segment elements whose lengths hardly change, and as a result, the irradiation amount per unit area changes and the printing depth changes. Variations can occur.

For example, when looking at a short line segment element (for example, length d1 × 2 + q) and a long line segment element (for example, length d1 × 8 + q) that produce the same fraction distance q, the reference distance interval d1 Is d1 + (q /
The distance interval is corrected to the distance interval of 2) and the distance interval of d1 + (q / 8) for long line segment elements. In other words, since the short line segment elements generate less coordinate data than the long line segment elements, the correction amount for the reference distance interval d1 is large. Therefore, the problem of the printing depth variation caused by the difference in printing speed between the line segment element in which the fractional distance occurs and the line element in which the fraction distance does not occur appears more remarkably for the line element having a relatively short distance. For example, a laser marking device may print a two-dimensional code such as the QR code shown in FIG. The two-dimensional code is configured by combining a plurality of fixed elements T in a desired arrangement.
Compared to dimensional codes (for example, so-called barcodes)
Much information can be encoded. In particular,
As shown in simplified form in FIG. 6 (B), small squares arranged vertically and horizontally in a matrix are given black to form a fixed element T. Due to the difference in arrangement of the fixed elements T, the manufacturing date, product number Etc. are coded. Fixed form element T
Is printed on an object by scanning with a laser beam along a scanning pattern P as shown in the upper left of FIG. Here, the fixed element T is an extremely narrow area,
The length of each line segment element constituting the scanning pattern P is also extremely short, and printing is performed in a state almost similar to one-point irradiation. Therefore, for such a very short line segment element,
As described above, when the reference distance interval d1 is corrected according to the fractional distance, the printing depth is different from that of the uncorrected line segment element, and the printing depth varies for each of the above-mentioned fixed form elements T. This makes the QR code unclear,
When reading a two-dimensional coat, a reading error may occur.

[0008] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a laser marking apparatus capable of printing marking information without variation in printing depth.

[0009]

According to a first aspect of the present invention, there is provided a laser marking apparatus, comprising: a laser light source for emitting a laser beam; Includes a galvano scanner that scans the irradiation point of laser light, and on / off control of the laser light source, and for each line element that constitutes a character, symbol, graphic, or the like to be printed, includes a start point that constitutes the line element. A laser marking device comprising: a controller that sequentially generates a plurality of pieces of coordinate data and sequentially supplies the respective pieces of coordinate data to the galvano scanner. Generated as coordinate data for each interval. Of the line segment elements, for the line segment elements whose length is not divisible by the length of the reference Is generated for each reference distance interval up to a point before the end point of the line segment element, and the coordinate data is sequentially supplied to the galvano scanner at a timing corresponding to the length of the reference distance interval. Having.

[0010]

According to the structure of the first aspect, the control means determines each of the line elements constituting the characters, symbols, figures, etc. to be printed, irrespective of the length of each of the line elements. The coordinate data for each given reference distance interval is sequentially generated from the starting point. Here, with respect to a line segment element having a length that is not divisible by the length of the reference distance interval and has a fractional distance, coordinate data for each constant reference distance interval is similarly generated from the start point to the point before the end point. And
Each of the coordinate data is sequentially provided to the galvano scanner at a timing corresponding to the length of the reference distance interval. In this way, regardless of the length of each line segment element, coordinate data is always generated for each fixed reference distance interval, and is provided to the galvano scanner at a fixed timing corresponding to the length of the reference distance interval. Therefore, the irradiation point of the laser beam always scans the object to be marked at a constant printing speed, so that characters, symbols, figures, and the like can be printed without variation in printing depth.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS <First Embodiment> A first embodiment of the present invention will be described with reference to FIGS. In FIG. 1, reference numeral 10 denotes a laser light source, and the laser light emitted from the laser light source is changed in direction by a galvano scanner 20 and is irradiated onto a target object W to be marked. The galvanometer scanner 20 includes a pair of galvanometer mirrors 20V and 20W.
And a converging lens 20Z. One galvanomirror 20W can change the reflection angle in the vertical direction by a driving means 20Y, and the other galvanomirror 20V
The reflection angle can be shifted in the lateral direction by the driving means 20X. Both galvanometer mirrors 20V, 2
The direction of the laser light can be adjusted in two orthogonal directions by 0W, and as a result, the irradiation point of the laser light can be moved to any position on the marking target object W. The converging lens 20Z is composed of, for example, an fθ lens, and converges the laser light reflected by the galvanometer mirrors 20V and 20W and focuses on the target object W (“irradiation point of laser light” of the present invention). It has the function of connecting

Each drive means 2 of the galvano scanner 20
0X and 20Y are controlled by the controller 30 corresponding to control means. A console (not shown) is connected to the controller 30 so that a desired character to be marked
When symbols, graphics, etc. are set in the console, the controller 30 gives data to the galvano scanner 20 according to the settings. More specifically, the controller 30
A memory for storing font data such as symbols and figures is built in. When a character or the like to be marked is set, line segment data constituting the character or the like is read based on the font data. Then, a CPU (not shown)
For each line segment element, a plurality of coordinate data for determining the irradiation position on the marking target object W is generated based on a control routine described below, and D / A converted to perform D / A conversion.
, And on / off control of the laser light source. Note that the marking speed can be set to a desired speed on the console.

Now, the contents of the control executed by the CPU will be described with reference to a flowchart shown in FIG. 3 and two line segment elements L10, L10 having different lengths shown in FIG.
11 will be described as an example. The length of the line segment element L10 is L10 (= the length of a reference distance interval d10 × 5 described later), and the length of the line segment element L11 is L11 (= the length of the reference distance interval d10 × 5).
+ Q10), both of which are shorter than the length LM of a reference segment described later.

First, when printing the line segment element L10,
In step S1, it is determined whether or not the length is smaller than a predetermined reference line length LM. If the length is shorter than the predetermined reference line length LM, in step S2, the line segment element L10 is set to a predetermined reference distance d10 (for example, 2 minutes of the spot diameter of the irradiation point). 1 is about 30 microns. In FIG. 2, a dotted circle indicates a spot outline, and it is determined whether or not the length is divisible by. Since the line segment element L10 is a length divisible by the reference line segment LM (Yes in step S2), as shown in FIG. 2A, the line segment element L10 is sequentially extended from the start point S to the end point E at every reference distance interval d10. The coordinate data of the two points is sequentially generated (step S3). The coordinate data is set at a fixed timing, in this embodiment, the marking speed V at which the reference distance interval d10 is set.
Are transferred to the galvano scanner 20 in order from the coordinate data of the starting point S at the timing of the time interval t (= d10 / V) calculated by dividing ON data is transferred (step S5). Then, simultaneously with the transfer of the coordinate data of the end point E, the OFF data is transferred to the laser light source 10 (step S6), and the laser light source is stopped. As a result, the galvano scanner 20 moves the irradiation point of the laser beam from the laser light source 10 on the target object W by the reference distance interval d10 at each time interval t, and the marking speed V set in advance. Will be printed at a constant speed.

On the other hand, when printing the line segment element L11,
Similarly to the above, it is determined that the length is shorter than the length LM of the reference line segment (Yes in step S1), and it is determined whether the length is divisible by the length of the reference distance interval d10. Line element L11
Is the length that produces the fractional distance q when divided by the reference distance interval d10 (No in step S2). Therefore, in step S4, from the start point S to a point just before the end point E (in this embodiment, the fifth point from the start point S), 6 points for each reference distance interval d10.
The coordinate data of the two points is sequentially generated. And the starting point S
The coordinate data of points from to the end point E is also sequentially transferred to the galvano scanner 20 at the timing of the time interval t (= d10 / V), and the ON data is transmitted to the laser light source 10 simultaneously with the transfer of the coordinate data of the start point S. Is transferred (step S5). Thereafter, simultaneously with the transfer of the coordinate data of the end point E, the OFF data is transferred to the laser light source 10 (step S6), and the laser light source 10 is stopped. Thereby, the irradiation point of the laser light from the laser light source 10 is also
The target object W is moved by the reference distance interval d10 at every time interval t, and printing is performed at a constant marking speed V set in advance.

With the laser marking device configured as described above, the two-dimensional code described in the conventional description (see FIG. 6)
Can be always printed at a constant printing depth for all the fixed-form elements T, thereby avoiding the problem of a reading error when reading.

The processing (described as "normal processing" in FIG. 3) for the line segment element having a length equal to or longer than the reference line segment LM (No in step S1) is not described. As in the case of the laser marking device, the reference distance d10 may be corrected according to the length of the line segment element.

Further, the present invention is applied only to line elements shorter than the reference line LM, but may be applied to line elements of all lengths. The reason for adopting the configuration as in the present embodiment is that, as described in the above-described conventional description, the correction amount for the reference distance interval d10 for the line segment element having a certain length is corrected even if the correction processing is performed by the conventional laser marking device. It is minute. Therefore, it is considered that the printing speed is not so different from the marking speed of the line segment element that does not require the correction processing and the difference in the printing depth does not occur.

As described above, for a line segment element having a length that is not divisible by the length of the reference distance interval d10 and has a fractional distance, such as the line segment element L11, the line element is located between the start point S and the end point E of the line element. Up to the point, a plurality of coordinate data is generated for each reference distance interval d10, and each coordinate data of a point before the start point S to the end point E is supplied to the galvano scanner 20 at every time interval t. Thereby, printing is performed at the same marking speed as the line segment element L10 that is divisible by the length of the reference distance interval d10, so that there is no variation in printing depth. Moreover,
Regardless of the length of each line segment element, coordinate data is always generated at a fixed reference distance interval d10 only at a part divisible by the reference distance interval d10, transferred at a fixed time interval t, and subjected to complicated correction processing such as feedback processing. Therefore, the effect can be exhibited for the purpose of speeding up the marking. In such a configuration, the line segment element L11 having a fractional distance is printed up to a point before the end point E,
Fractional distance parts are not printed. However, in the present embodiment, the fractional distance is extremely small, for example, less than about 30 microns (half the spot diameter of the irradiation point) as described above, so that the substantial influence is not exerted. Absent.

<Other Embodiments> The present invention is not limited to the above embodiments. For example, the following embodiments are also included in the technical scope of the present invention.
In addition to the following, various changes can be made without departing from the scope of the invention.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a laser marking device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing the relationship between the length of each line segment element, coordinate data, and marking speed.

FIG. 3 is a control routine performed by a CPU.

FIG. 4 is an explanatory diagram showing the relationship between the length of each line segment element and coordinate data of a conventional laser marking device (part 1).

FIG. 5 is an explanatory diagram showing the relationship between the length of each line segment element and coordinate data (part 2).

FIG. 6 is a schematic diagram showing a QR code.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Laser light source 20 ... Galvano scanner 30 ... Controller (control means) E ... End point S ... Start point L10, L11 ... Line segment element W ... Marking target object d10 ... Reference distance interval q10 ... Fractional distance

Claims (1)

[Claims] A laser light source that emits a laser light; a galvano scanner that scans an irradiation point of the laser light on an object to be marked by changing a direction of the laser light; and performs on / off control of the laser light source. For each of the line elements constituting the characters, symbols, figures, etc. to be printed, a plurality of coordinate data including the starting points constituting the line elements are sequentially generated, and each of the coordinate data is sent to the galvano scanner. In the laser marking device comprising a control means for sequentially giving, the control means generates the plurality of coordinate data as coordinate data for each predetermined constant reference distance interval,
Among the line segment elements, for a line segment element having a fractional distance that is not divisible by the length of the reference distance interval, a plurality of coordinate data including the start point is obtained for each of the reference distance intervals. A laser marking apparatus which generates up to a point before an end point and sequentially supplies the respective coordinate data to the galvano scanner at a timing corresponding to the length of the reference distance interval.