JP2002018581A - Laser beam marking device and laser beam mark media - Google Patents

Abstract

PROBLEM TO BE SOLVED: To save time when a laser beam marking is performed by scanning an object with a laser beam reflected on a rotating polygonal mirror. SOLUTION: The laser beam marking device 10 comprises a laser beam oscillator 12, a transport unit 16 which transports the object 14 to be marked in a specified direction, and a rotating polygonal mirror 18 located between them. A laser-beam mark is formed by scanning the object 14 to be marked with the laser beam reflected on the polygonal mirror 18 while the object 14 to be marked is transported by the transporting unit 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser marking device for marking characters, images, bar codes, etc. on metal transfer foils, hologram transfer foils, labels, seals, and the like by using a laser beam, and a laser marking device. It relates to a laser mark medium.

[0002]

2. Description of the Related Art Heretofore, cards, such as stock certificates, gift certificates, etc., cards, such as credit cards, prepaid cards, ID cards, etc., metal transfer foils, hologram transfer foils, labels, seals, etc., have been irradiated with laser beams to write letters, bars, etc. There is a laser marking device for marking a code or the like.

In such a laser marking apparatus, a method of scanning a marking object with a laser beam in a predetermined direction is generally a method of scanning a laser beam two-dimensionally using two galvanometers. It is.

In this method, since the laser beam is scanned in one stroke, it is difficult to control a galvanometer for the scanning.

In order to solve such a problem, a laser marking device as disclosed in, for example, Japanese Patent Application Laid-Open No. 3-243289 has been proposed.

In this laser marking device, a rotary polygon mirror is provided on a print head that performs reciprocating operation, and a laser beam is scanned in two directions by a reciprocating motion of the print head and a rotary motion by the rotary polygon mirror. Thereby, the scanning control of the laser beam is simplified.

[0007]

However, the laser marking device disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 3-243289 requires two control systems, that is, a reciprocating motion of a print head and a rotary motion of a polygon mirror. In addition, since the print head reciprocates, there is a problem that wasted time is generated during the reciprocation, and the time required for marking is increased.

Further, since the line width of the laser mark on the marked medium becomes large at the beginning and end, there is a problem that high-definition marking with a high line density in the width direction cannot be performed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and further simplifies a laser beam scanning system and eliminates wasted time during scanning to perform efficient marking. It is an object of the present invention to provide a laser marking device capable of performing a laser marking and a laser mark medium marked with high definition by the laser marking device.

[0010]

According to the present invention, there is provided a laser oscillator for emitting a laser beam for marking, a transport unit for transporting a marking object in a fixed direction, and a transport unit. Is provided rotatably at a fixed position, reflects the laser beam emitted from the laser oscillator in the direction of the marking object transported by the transport unit, and the marking object in a non-parallel direction to the transport direction. A polygon mirror for scanning the object, and a control device for modulating the laser beam, in synchronization with at least the rotation state of the polygon mirror, among the transport state of the marking object and the rotation state of the polygon mirror, The above object is achieved by a laser marking device.

In the laser marking apparatus, a detection laser source for irradiating the polygon mirror with a detection laser beam, and a laser for emitting the detection laser beam emitted from the detection laser source and reflected by the polygon mirror And a detector, wherein the control device modulates the laser beam based on an output signal of the laser detector.

Further, in the laser marking apparatus, at least one of the marking target and the transport unit is provided with a timing mark indicating a position of the marking target in the transport direction, and a timing mark detector for detecting the timing mark is provided. The control device may modulate the laser beam based on a detection signal from the timing mark detector.

A laser mark is recorded by the laser marking device as described above, and the line width of the laser mark is substantially the same from the beginning to the end of the line. The above object is achieved by a medium.

According to the present invention, the scanning portion of the laser beam is only the rotational movement by the rotary polygon mirror, and the scanning system is extremely simplified. Further, since there is no useless time as in the case of reciprocating the print head, efficient laser marking can be performed.

Further, since the line width of the laser mark is uniform, it is possible to obtain a laser mark medium on which high-definition marking is performed.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings.

As shown in FIG. 1, a laser marking device 10 according to an embodiment of the present invention includes a laser oscillator 12 that emits a marking laser beam, and a transport unit 16 that transports a marking object 14 in a certain direction. When,
The laser unit 12 is provided rotatably at a fixed position with respect to the transport unit 16, and reflects a laser beam emitted from the laser oscillator 12 in the direction of the marking object 14 transported by the transport unit 16. A polygon mirror 18 that scans the marking object 14 in a direction orthogonal to the transport direction, and a control device 20 that modulates the laser beam in synchronization with a transport state of the marking object 14 and a rotation state of the polygon mirror 18. It is comprised including.

The polygon mirror 18 is, for example, a polygon mirror and includes a motor (not shown).
4, it is designed to be rotationally driven in a plane parallel to the paper surface in FIG.

From the laser oscillator 12 to the polygon mirror 18
A laser modulator 22, a half mirror 28, and a beam expander 30 are arranged in this order on the optical path of the laser beam from the laser oscillator 12 side.

The laser modulator 22 includes the control device 2
By 0, for example, control is performed to perform intensity modulation of the laser beam.

A semiconductor laser 32 for emitting a laser beam for detection is arranged beside the half mirror 28,
The detection laser beam is emitted in the optical path of the laser beam from the half mirror 28 to the polygon mirror 18 from the laser oscillator 12.

In the range where the detection laser beam from the semiconductor laser 32 is reflected by the polygon mirror 18, the F-.theta.
A laser detector 34 is disposed at a position passing near one limit in the scanning direction in.

The detection signal of the detection laser beam by the laser detector 34 is output to the control device 20.

The control device 20 modulates the laser modulator 22 based on a detection signal from a laser detector 34.

An F-θ lens 36 is disposed between the polygon mirror 18 and the transport unit 16 on the optical path of the reflected light of the laser beam reflected by the polygon mirror 18.

In the embodiment of the present invention, the transport unit 16 includes a supply unit 16A for unwinding and supplying the sheet-like marking object 14, and a winding unit for winding the unwound marking object 14. 16B, and as shown in FIG. 2, the sheet-like marking object 14 is conveyed downward at a constant speed.

On the other hand, the polygon mirror 18 is provided so as to scan the reflected laser beam in a direction perpendicular to the direction in which the marking object 14 is transported in the transport unit 16.

Here, the laser oscillator 12 only needs to be capable of emitting a laser beam having an energy capable of marking the object 14 to be marked. For example, He-C
Lasers commonly used such as d laser, He-Ne laser, ruby laser, semiconductor laser, YAG laser, Nd: glass laser, excimer laser, dye laser, nitrogen laser, argon laser, carbon dioxide laser, etc. Good. The method of laser oscillation may be either continuous oscillation or pulse oscillation.

Furthermore, the laser modulator 22 is used because it is necessary to modulate a laser beam when marking an arbitrary pattern, character, or the like on the marking object 14.

When marking is performed on the entire surface on which laser marking is to be performed, no modulation is necessary, but marking is started on the marking object 14 at a predetermined timing.
In order to complete the operation, the laser beam power is incompletely turned on / off or completely turned on / off depending on whether the power of the laser beam is higher or lower than a threshold value at which the marking object 14 can be marked.

More specifically, any of a device using a mechanical shutter, a device using a rotating prism, a device using an electro-optic effect such as the Kerr effect and the Pockels effect, and a device using an acousto-optic effect such as a flag cell may be used.

The polygon mirror 18 is generally a polygon mirror, but may be another polygon mirror.

The beam expander 30 optically corrects the laser beam passing through the half mirror 28.

Next, a process of marking the marking object 14 by the laser marking device 10 will be described.

First, the marking object 14, for example, a transfer foil in the form of a roll, is attached to the transport unit 16. The transport unit 16 is operated to transport the marking object 14 downward at a constant speed in FIG.

Next, the polygon mirror 18 is rotated at a constant speed by the polygon mirror driving device 24, and the laser oscillator 12 is driven to emit a laser beam. At this stage, the laser beam is cut off by the laser modulator 22.

On the other hand, the semiconductor laser 32 is driven to emit a detection laser beam. The detection laser beam is
The light is reflected by the half mirror 28 and reaches the polygon mirror 18, where it is reflected and passes through the F-θ lens 36 and reaches the laser detector 34 in synchronization with the rotation of the polygon mirror 18. The laser detector 34 outputs a detection signal to the control device 20 each time the reflected detection laser beam is input.

The controller 20 performs one of the scanning operations of the polygon mirror 18 in accordance with the data to be marked at a timing synchronized with the detection signal, that is, at a timing synchronized with the rotation of the polygon mirror 18.
The pulse signal for the line is output to the laser modulator 22.

The laser modulator 22 modulates the intensity of the laser beam in accordance with a signal input from the control device 20 so that the polygon mirror 18 performs one scanning, that is, one line of marking. Become.

By repeating the above operation each time the laser detector 34 detects a signal, a predetermined marking is made on the marking object 14.

Each time the laser beam is scanned by the polygon mirror 18 in the direction perpendicular to the scanning direction, the marking object 14 is sent by the transport unit 16 in a direction orthogonal to the scanning direction. By modulating the intensity of the laser beam in the section, a predetermined picture or character can be formed on the marking object 14. For example, a laser mark medium 44 (detailed later) having a laser mark pattern as shown in FIG. 3 can be formed.

The laser mark medium 44 shown in FIG. 3 is an example of a marking object laser-marked by the laser marking device 10 or 40.

In the laser mark medium 44, the line width of the marking line 45 is changed from the starting end 45A to the ending end 45A.
It is almost constant up to 5B, and a circular portion due to concentration of laser power does not occur at the start end 45A and the end 45B.

Therefore, when forming a hologram or the like, the gap between the marking lines 45, that is, the pitch can be reduced to form a fine display.

At this time, the marking object 14 can be fed intermittently and at a high speed.
There is no need to provide a waiting time for the scanning of the laser beam by the laser beam 8, so that a large number of marking objects 14 can be efficiently laser-marked.

The control device 20 in the example of the above embodiment
Indicates that the control of the laser modulator 26 is started and ended based on an independent command and operation after the conveyance of the marking object 14 by the conveyance unit 16 is started. May be detected, and the laser modulator 22 may be controlled in synchronization with the detection signal.

For example, a laser marking device 40 according to a second embodiment of the present invention shown in FIG. 4 is provided with a timing mark 15 indicating the position in the transport direction on the marking object 14, and this timing mark The control device 20 modulates the laser modulator 22 based on a detection signal from the timing mark detector 42.

The timing mark 15 is a print mark, a hole, a groove, or the like.
May be any sensor that can detect these by light or the like.

It is to be noted that, for example, in the supply unit 16A or the winding unit 16B of the transport unit 16,
The timing mark 15 may be provided at a location not covered by the timing mark 4 and detected by the timing mark detector 42.

In the example of the above embodiment, the intensity modulation of the laser beam for laser marking is performed by the laser modulator 22, but the present invention is not limited to this, and the laser oscillator 12 itself may be modulated. On / off or intensity modulation may be performed.

For example, if a semiconductor laser is used as the laser oscillator 12, intensity modulation can be performed by controlling the current supplied to the semiconductor element.

In a laser using a laser beam of a semiconductor laser as a pumping light, for example, a YAG laser excited by a laser beam, a current value supplied to a semiconductor laser as a pumping light source is controlled to control a laser oscillator. Laser beam intensity modulation can be performed.

When a pulse laser is used as the laser oscillator 12, the pulse light is generated by a Q switching element. By controlling the timing of the Q switching element, the modulation (on / off modulation) of the laser light is performed. )It can be performed.

The transport unit 16 includes a supply unit 16
The sheet-like marking object 14 is transported from A to the winding unit 16B, but the present invention is not limited to this. For example, a scanning stage that performs a uniaxial reciprocating motion, a rotating drum, A belt conveyor or the like can be used as a transport unit.

The direction of transport of the marking object by the transport unit is not limited to the orthogonal direction, and may be an inclined direction, as long as it is not the same as the scanning direction of the laser beam by the polygon mirror 18. That is, the scanning direction of the laser beam may be non-parallel to the transport direction.

Further, in the above embodiment, the beam expander 30 and the half mirror 28 are provided on the optical path of the laser beam between the laser oscillator 12 and the polygon mirror 18. The present invention is not limited to this. When it is necessary to form an image of the laser beam on the marking object 14, an imaging lens, a necessary focal position, an F-θ lens for correcting a beam shape, a cylinder, A Dolkar lens or the like may be provided.

[0057]

According to the present invention, the laser beam is rotated and reflected by the polygon mirror to scan the object to be marked. It has an excellent effect of being able to.

[Brief description of the drawings]

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

FIG. 2 is a schematic side view showing a polygon mirror and a transport unit in the laser marking device.

FIG. 3 is a plan view showing a main part of a laser mark medium laser-marked by the laser marking device.

FIG. 4 is a block diagram showing a laser marking device according to a second example of the embodiment;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Laser marking device 12 ... Laser oscillator 14 ... Marking object 15 ... Timing mark 16 ... Convey unit 18 ... Polygon mirror 20 ... Control device 22, 26 ... Laser modulator 24 ... Polygon mirror drive device 28 ... Half mirror 30 ... Beam Expander 32 Semiconductor laser 34 Laser detector 36 F-θ lens 42 Timing mark detector 44 Laser mark medium 45 Marking line 45A Start end 45B End

Claims (4)

[Claims] 1. A laser oscillator for emitting a marking laser beam, a transport unit for transporting an object to be marked in a fixed direction, and a rotatable unit provided at a fixed position with respect to the transport unit. The laser beam is reflected in the direction of the marking object transported by the transport unit, and a polygon mirror that scans the marking object in a non-parallel direction to the transport direction,
Of the transport state of the marking object and the rotation state of the polygon mirror, at least in synchronization with the rotation state of the polygon mirror,
And a control device for modulating the laser beam. 2. A detecting laser source for irradiating a laser beam for detection onto the polygon mirror, and detecting a laser beam emitted from the detection laser source and reflected by the polygon mirror. A laser detector, wherein the control device modulates the laser beam based on an output signal of the laser detector. 3. The apparatus according to claim 1, wherein a timing mark indicating a position of the marking object in the transport direction is provided on at least one of the marking object and the transport unit, and a timing mark detector for detecting the timing mark is provided. A laser marking device, wherein the control device modulates the laser beam based on a detection signal from the timing mark detector. 4. A laser marking device according to claim 1, wherein a linear laser mark is recorded, and the line width of the laser mark is substantially the same from the beginning to the end of the line. Laser mark medium.