JPH11197862A - Laser marking equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To to attain a required power density distribution of a laser beam and to realize a laser marking equipment exact and excellent in visibility by executing modified adjustment of transmission rate distribution of shattering matrix expressible in gradations. SOLUTION: A laser beam ahead of being made incident on a liquid crystal 10 through a beam sampler 3 is inputted in a control part 6 from a monitoring camera 5, and a power density distribution of the laser beam is detected. The control part 6 generates a corrected transmission rate pattern in order to unify the detected power density distribution, decides a transmission rate pattern of the liquid crystal 10 from the corrected transmission rate pattern and from a transmission rata pattern to carry out print of required letters or others, and with this decided transmission pattern the laser beam 1 is made to transmit the liquid crystal 10 to print on a working object 12. Thereby, it is made possible to adjust the laser beam power density distribution to a required power density distribution and to execute print exact free from thinning or others and excellent in visibility.

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 irradiating a workpiece with a laser beam for printing.

[0002]

2. Description of the Related Art In a conventional laser marking apparatus, a metal mask method or a liquid crystal method is used. The mask method used was used.

That is, a laser beam emitted from a laser oscillator is applied to a liquid crystal mask via a lens forming a beam expander. Printing information is supplied to the liquid crystal mask from the signal control unit, and a laser beam is emitted from only the portion to be printed from the liquid crystal mask.

[0004] Laser light emitted from the liquid crystal mask is applied to a work to be printed via a beam splitter and a projection lens, and is printed on the work to be printed.

[0005]

However, in the above-mentioned conventional laser marking apparatus, when used for a package marker, for example, the laser output from the laser oscillator is non-uniform as shown in FIG. In addition, when the power density distribution is asymmetric, when transferred to a workpiece to be printed, there is a problem that blurring or the like occurs and visibility deteriorates.

In this case, a certain degree of uniformity of the power density distribution can be expected by adjusting the laser optical axis or the like. However, nonuniformity of the power density distribution of the laser output is inevitably generated, and the image forming surface (workpiece) In some cases, the power density at the surface (surface) is too low or too high, and the above-mentioned blurring or the like occurs.

It is conceivable to set conditions and the like for the image forming range and the target work to suppress the occurrence of blurring and the like. However, when the image forming range and the target work are changed, the setting is performed again. Conditions have to be adjusted, which is complicated.

Further, even in the same image forming range and the target work, the characteristics and the like of the apparatus fluctuate under the influence of the environment and the like of the apparatus.
It is also conceivable that the non-uniformity of the power density distribution of the laser output increases, making it difficult to perform stable printing.

It is an object of the present invention to change the power density distribution of a laser beam to a desired power density distribution by changing and adjusting the transmittance distribution of a shuttering matrix capable of expressing gradation. Excellent visibility,
Another object of the present invention is to realize a laser marking device capable of performing various printing.

[0010]

In order to achieve the above object, the present invention is configured as follows. (1) In a laser marking device that irradiates a laser beam output from a laser oscillator onto a workpiece and prints on the workpiece in a desired pattern, the laser beam output from the laser oscillator is used for pattern formation. Is transmitted by a mask formed of a shuttering element matrix capable of expressing gradations and having a transmittance distribution according to a desired print pattern, and the desired pattern is transferred onto the surface of the workpiece.

[0011] The above-mentioned mask makes a marking on the object to be processed with a desired power density distribution without depending on the power density distribution of the laser beam output from the laser oscillator. Therefore, marking can be performed with a laser beam having a uniform power density distribution.

(2) Preferably, in the above (1),
Monitoring means for monitoring the laser light output from the laser oscillator before irradiating the mask, and for uniformizing the power density distribution based on the power density distribution of the laser light monitored by the monitoring means. And a control unit that calculates the transmittance distribution of the mask and controls the mask so that the calculated transmittance is obtained.

The transmittance distribution of the mask is calculated by the control unit so that the power density distribution of the laser light monitored by the monitoring means is made uniform. Therefore, by the laser beam having a uniform power density distribution,
Marking becomes possible.

(3) Preferably, in the above (1), the mask is capable of expressing three or more gradations.
The transmittance distribution of the mask is determined based on a desired gradation pattern including three or more gradations and the desired print pattern.

The transmittance distribution of the mask is determined based on a desired gradation pattern consisting of three or more gradations and a desired printing pattern, and a laser beam is transmitted through the mask, and By printing on an object, a mark expressing desired shading can be printed on a workpiece.

[0016]

Embodiments of the present invention will be described below with reference to the accompanying drawings. In the embodiment of the present invention, each shutter element has a characteristic as shown in FIG. 2, that is, the transmittance is 100% until the applied voltage rises to a predetermined value. %, And when the applied voltage exceeds a predetermined value, a liquid crystal having a characteristic that its transmittance decreases with an increase in the applied voltage is used. Then, a laser marker for changing and adjusting the transmittance distribution by adjusting the applied voltage will be described as an example.

FIG. 1 is an overall configuration diagram of a laser marker according to a first embodiment of the present invention. In FIG. 1, the laser oscillator 2 is supplied with power from a laser power supply 9, and the laser oscillation is controlled by a laser oscillation control unit 8. The laser light 1 output from the laser oscillator 2 is converted into linearly polarized light by a polarizing element (1/4 wavelength plate) 13. However, when the laser output light from the laser oscillator 2 is linearly polarized, the polarizing element 13 is unnecessary. The laser beam 1 that has passed through the polarizing element 13 is converted into a beam sampler 3
As a result, a part of the light enters the observation camera (monitor camera) 5 via the imaging lens 4 and is imaged on the camera 5.

The image information captured by the observation camera 5 is supplied to the control unit 6, and the control unit 6 refers to the power density distribution of the currently output laser beam 1.

Next, it is assumed that the power density distribution referred to from the image information captured by the observation camera 5 has a non-uniform distribution as shown in FIG.
This power density distribution is a power density distribution at a position C in FIG. 1).

When averaging the power distribution density with respect to the non-uniform power distribution density, for example, the control unit 6 controls the reverse of the pattern of the characteristic of the distance d1 to d2 of the power distribution density shown in FIG. Create a transmittance pattern for the pattern. That is, a transmittance pattern of a pattern having a line-symmetrical shape of the power density distribution from the distance d1 to the distance d2 with respect to the power P0 in FIG. 3 is created.

Then, the controller 6 applies a voltage to the liquid crystal 10 so as to obtain the created transmittance pattern. The laser light 1 that has passed through the beam sampler 3 and further has passed through the liquid crystal 10 has a non-uniform power density distribution shown in FIG. The laser beam 1 having the uniformized power density distribution is applied to the workpiece 12 via the imaging lens 11, so that good marking without blurring can be performed.

Here, a case where the character H shown in FIG. 5 is printed on the workpiece 12 by using the laser marker shown in FIG. 1 will be described as an example. When the power density distribution of the laser beam is uniform, the line A of the character H in FIG.
Is a rectangular transmittance distribution as shown in FIG. If the power density distribution of the laser light 1 captured by the camera 5 is the same as that shown in FIG. 3, the transmittance distribution data (shown in FIG. 4) of the liquid crystal 10 for averaging the power density distribution is used. The transmittance pattern shown in FIG. 6 is corrected, and transmittance distribution data as shown in FIG. 7 is created.

As described above, a modified transmittance distribution of the liquid crystal 10 for averaging the power density distribution of the laser light 1 is created from the sampling data of the laser light 1 captured by the camera 5. Then, from the calculation of the transmittance distribution for the desired print pattern and the corrected transmittance distribution, a transmittance pattern of the liquid crystal 10 optimal for the desired print can be created.

Thereafter, the control unit 6 applies the voltage applied to the liquid crystal 10 shown in FIG.
The voltage to be applied to each element of the liquid crystal 10 is determined based on the relationship with the laser transmittance, and applied to the liquid crystal 10.

As a result, the laser beam 1 having a power density as shown in FIG. 5 incident on the liquid crystal 10 is output in a uniform pattern. Thereafter, when the laser beam 1 transmitted through the liquid crystal is irradiated on the work piece 12 by the lens 11 that forms an image, it is possible to mark a uniform H character.

As described above, according to the first embodiment of the present invention, the power density distribution of the laser beam before being incident on the liquid crystal 10 is detected, and the correction for uniforming the detected power density distribution is performed. A transmittance pattern is created, and a transmittance pattern of the liquid crystal 10 is determined from the corrected transmittance pattern and a transmittance pattern for printing desired characters and the like. 1 is transmitted and printed on the workpiece 12.

Therefore, the power density distribution of the laser beam can be adjusted to the desired power density distribution by changing and adjusting the transmittance distribution of the shuttering matrix capable of expressing gradations, and the power density distribution can be made accurate without blurring. Thus, it is possible to realize a laser marking device capable of performing printing with excellent visibility.

FIG. 8 is a functional block diagram of the control unit 6 of the laser marking device according to the second embodiment of the present invention. In addition, about other structures, the 1st shown in FIG.
Since this embodiment is the same as the embodiment, illustration and description thereof are omitted.

In the above-described first embodiment, the laser light is
This is an example in which the transmittance pattern of the liquid crystal 10 is adjusted so as to have a uniform power density distribution. However, by adjusting the gradation of the shuttering element matrix capable of expressing gradation, desired gradation can be expressed. An example is the second embodiment of the present invention.

In FIG. 8, monitor camera data 6a from the monitor camera 5 is supplied to a uniformized data creation unit 6b of the control unit 6. Then, the uniformized data creating unit 6 creates the modified transmittance data for equalizing the power distribution density of the monitored laser light in the same manner as in the first embodiment described above. Then, the created modified transmittance data is supplied to the arithmetic processing unit 6e.

The symbol data storage unit 6c stores symbol data to be marked, and the symbol data (H mark in this example) is stored in the arithmetic processing unit 6e.
Supplied to

Further, a gradation data storage section 6d
Stores the desired gradation data (in the case of grayscale data, in this example, data whose density decreases as approaching the center from both sides). The gradation data is also stored in the arithmetic processing unit 6e. Supplied.

Then, no operation processing 6e is supplied,
According to the relationship between the liquid crystal applied voltage and the transmittance shown in FIG. 2 in accordance with the corrected transmittance data, the design data, and the gradation data, the transmittance of the liquid crystal 10 for printing the H mark on which the desired gradation is applied is determined. Calculate the applied voltage to become The calculated applied voltage data 6f is
The voltage is supplied to the liquid crystal applied voltage generator 6 g, converted into an actual voltage, and supplied to the liquid crystal 10.

As a result, the laser beam transmitted through the liquid crystal 10 is irradiated on the object to be processed with an energy distribution according to the transmittance distribution of the liquid crystal 10, and an H mark in which the density is expressed as shown in FIG. It can be printed on the workpiece.

As described above, the fact that the density of the print on the object to be processed can be expressed means that the power of the laser beam applied to the object to be processed can be partially changed. That is, as shown in FIG. 10, when the mark to be printed becomes thinner from both sides toward the center, the processing depth in the cross section along the line DD ′ is deep on both sides, and Processing with a 2.5-dimensional or 3-dimensional spread that becomes shallower as approaching becomes possible.

Therefore, by utilizing the above-mentioned controllability of the processing depth of the processing object, marking having a plurality of colors can be performed.

That is, as shown in FIG. 11, it is assumed that several layers of coloring materials are stacked on the surface of the object to be processed. For example,
A coloring material is stacked in the order of a red layer, a green layer, and a blue layer to form a multilayer surface. Then, if the processing depth to the workpiece is controlled so that it becomes shallower as it approaches the center from both sides of the print, for example, if both sides are red, the center part is blue, and the distance between both sides and the center part, It is possible to print the English letter H whose area is colored green.

Further, by applying a substance having a different color depending on the calorific value of the laser beam radiated on the surface of the object to be processed, it is possible to have an arbitrary plurality of colors in the same manner as in the case of forming the above-described color forming material into a multilayer. Marking of characters and the like becomes possible.

As described above, according to the second embodiment of the present invention, the power density distribution of the laser beam before being incident on the liquid crystal 10 is detected, and the correction for uniforming the detected power density distribution is performed. A transmittance pattern is created, and a transmittance pattern of the liquid crystal 10 is determined from the corrected transmittance pattern, a transmittance pattern for printing desired characters and the like, and desired gradation data (shading data). The laser beam 1 is transmitted through the determined transmittance pattern, and printing is performed on the workpiece 12.

Therefore, the power density distribution of the laser beam can be adjusted to the desired power density distribution by changing and adjusting the transmittance distribution of the shuttering matrix capable of expressing gradations, and it is possible to obtain a precise power density distribution without blurring. In addition, it is possible to realize a laser marking device capable of performing printing with excellent visibility and performing various printings with gradation.

Furthermore, if the surface of the object to be processed is formed of a multi-layered color developing material of a plurality of colors and the processing depth of the object to be processed by laser light is controlled, characters having arbitrary plural colors can be obtained. And the like can be realized.

In the above example, the laser light 1 is monitored by the beam sampler 3 and the camera 5 to determine the transmittance distribution of the liquid crystal 10. However, the power density distribution of the laser light 1 is known. In the case of (1), without monitoring the laser beam, the liquid crystal 1 is adjusted to have a transmittance distribution for correcting a known power density distribution.
It can also be configured to control 0.

In this case, if the power density distribution of the laser beam changes due to a change in the use environment such as the temperature, the change in the use environment such as the temperature can be obtained. Accordingly, the transmittance distribution of the liquid crystal 10 can be changed and adjusted.

[0044]

Since the present invention is configured as described above, it has the following effects. By changing and adjusting the transmittance distribution of the shuttering matrix capable of expressing the gradation of the power density of the laser beam, it is possible to obtain a desired power density distribution, and it is accurate without blur and has excellent visibility. It is possible to realize a laser marking device capable of performing the printing.

The transmittance pattern of the liquid crystal is determined from the corrected transmittance pattern, the transmittance pattern for printing desired characters and the like, and the desired gradation data (shading data). If the laser beam is transmitted in a rate pattern and printed on the workpiece, accurate and highly visible printing without blurring is possible, and various gradation printing is performed. It is possible to realize a laser marking device capable of performing the above.

[Brief description of the drawings]

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

FIG. 2 is a diagram showing a change curve of transmittance with respect to an applied voltage of a liquid crystal.

FIG. 3 is a diagram illustrating an example in which laser light output from a laser oscillator has a bias in a power density distribution.

FIG. 4 is a diagram showing a modified transmittance distribution of the liquid crystal calculated by the control unit.

FIG. 5 is a diagram illustrating an example of characters displayed on a liquid crystal.

FIG. 6 is a diagram showing a portion along the line A of the character shown in FIG. 5 when the power density distribution of the laser beam is uniform, which is the transmittance distribution of the liquid crystal.

FIG. 7 is a view showing a transmittance obtained by correcting the transmittance of the liquid crystal shown in FIG. 6;

FIG. 8 is a functional block diagram of a control unit of a laser marking device according to a second embodiment of the present invention.

FIG. 9 is a diagram illustrating an example of gradation-applied marking.

FIG. 10 is a diagram illustrating adjustment of a processing depth of a workpiece according to a second embodiment of the present invention.

FIG. 11 is a diagram illustrating an example in which marking having a plurality of colors is possible.

FIG. 12 is a diagram illustrating an example in which a laser beam 1 output from a laser oscillator has a bias in a power density distribution.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 laser light 2 laser oscillator 3 beam sampler 4 imaging lens 5 camera 6 control unit 6 b uniform data creation unit 6 c design data storage unit 6 d gradation data storage unit 6 e arithmetic processing unit 6 g liquid crystal applied voltage generation unit 8 laser oscillation control unit 9 Laser power supply 10 Liquid crystal 11 Imaging lens 12 Workpiece 13 Polarizing element (1/4 wavelength plate)

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁶ Identification code FI G02B 27/09 B41J 3/00 Q G02F 1/133 575 G02B 27/00 E (72) Inventor Yasushi Minomoto Yasushi, Tsuchiura-shi, Ibaraki 650-machi Hitachi Construction Machinery Engineering Co., Ltd.

Claims (3)

[Claims] A laser marking device for irradiating a laser beam output from a laser oscillator onto a workpiece to print on the workpiece in a desired pattern. The desired printing pattern is formed by a shuttering element matrix capable of expressing gradation for formation, is transmitted through a mask having a transmittance distribution according to a desired printing pattern, and is irradiated with a laser beam having a desired power density distribution. A laser marking device for transferring an image onto a surface of a workpiece. 2. A laser marking apparatus according to claim 1, wherein a monitoring means monitors the laser light output from the laser oscillator before irradiating the mask, and a power density distribution of the laser light monitored by the monitoring means. A control unit for calculating the transmittance distribution of the mask for equalizing the power density distribution based on the control, and controlling the mask so that the calculated transmittance is obtained. Laser marking device. 3. The laser marking apparatus according to claim 1, wherein the mask is capable of expressing three or more gradations.
A laser marking apparatus, wherein the transmittance distribution of the mask is determined based on a desired gradation pattern including three or more gradations and the desired print pattern.