JPH08279635A - Laser irradiator - Google Patents

Abstract

PURPOSE: To easily observe an object irradiated with a laser beam through a simple structure. CONSTITUTION: A laser beam 2 from a laser head is made to impinge on a recording medium on an opposite side being reflected by a reflecting mirror 3 and polarizing mirrors 4 and 5. The laser beam 2 is two-dimensionally polarized by the polarizing mirrors 4 and 5, whereby an picture image is formed on the recording medium. The reflecting mirror 3 is composed of a glass plate 3a and a dielectric multilayered film 3b formed on the surface of the glass plate 3a and capable of fully reflecting only light rays of certain narrow wavelength band where the laser beam 2 is included and transmitting the other light rays. Therefore, the picture image of an irradiated object formed on the recording medium is mirrored on the mirrors 5 and 4, and the mirrored picture image of the object can be observed through an observation window 9 and a reflecting mirror 3 provided to a case 14. The laser beam 2 is reflected by the reflecting mirror 3 and hardly penetrates through the reflecting mirror 3, so that laser beams are leaked out little through the window, and a laser irradiation is kept high in safety.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser irradiation device for irradiating a laser beam to form an image on a recording medium or an inner layer of the recording medium, or for irradiating a laser beam to process an object.

[0002]

2. Description of the Related Art Since a laser beam can be made into an extremely thin beam, it is widely used for precisely drawing figures and characters on a recording medium or for precisely processing a metal or plastic plate. There is. For example, in a laser drawing device, paper coated with a heat-sensitive material is used as a recording medium, the surface thereof is irradiated with a laser beam, and the deflecting means such as a galvanometer mirror is used to deflect the laser beam to draw characters or figures. are doing. On the other hand, in a laser processing machine, laser light is generated by a high-power laser light source, sharply converged, and irradiated onto a metal or plastic plate to be processed. Then, similarly, a galvanometer mirror or the like is used to deflect the laser beam to cut the plate into a complicated shape or to punch a hole in the plate.

[0003]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention In these laser drawing devices and laser processing machines, laser light emitted in the device,
Alternatively, since scattered laser light may adversely affect the human body, the entire optical path of the laser beam from the laser light source to the laser beam irradiation portion is tightly covered with a cover, and the laser light does not leak outside. Has become. The cover is screwed to the frame so that it cannot be easily removed.

Depending on the application, it may be necessary to confirm the progress status during drawing or processing of the irradiation target, or to check whether the drawing or processing is performed correctly. . Therefore, conventionally, a method has been adopted in which a small television camera equipped with a CCD or the like is incorporated in the apparatus, a recording medium irradiated with a laser beam or an object to be processed is photographed, and the image is observed on a monitor television. It was However, as a result of incorporating a television camera or installing a monitor television in this way, there arises a problem that the device becomes complicated and large, and the cost becomes high.

An object of the present invention is to solve the above problems and to provide a laser irradiation apparatus which simplifies the structure and reduces the cost by making it possible to observe an object to be irradiated with a laser beam with a simple structure. It is in.

[0006]

To achieve the above object, the present invention provides a laser emission source for irradiating a laser beam, and an optical deflector for two-dimensionally deflecting the laser beam to irradiate an irradiation target. In a laser irradiation device including a cover for covering an optical path of a laser beam from the laser emission source to an irradiation target, a reflecting mirror for reflecting the laser beam toward the optical deflector is provided, and the reflecting mirror is a transparent substrate. ,
And a transparent dielectric multilayer film coated thereon, and a window is provided in the cover portion located behind the reflecting mirror.

The present invention is also characterized in that the reflecting mirror bends the optical path of the laser beam by approximately 90 °. The invention is also characterized in that the substrate is made of glass or plastic. The present invention is also characterized in that the window is closed by a plate composed of a transparent substrate and a transparent dielectric multilayer film coated thereon. The invention is also characterized in that the substrate is made of glass or plastic.

The present invention also provides a laser emission source for irradiating a laser beam, an optical deflector for two-dimensionally deflecting the laser beam to irradiate the irradiation target, and a laser beam from the laser emission source to the irradiation target. In the laser irradiation device having a cover for covering the optical path, the window is provided at the cover portion where the irradiation target can be visually recognized. The present invention is also characterized in that the laser irradiation device constitutes a laser drawing device which forms an image on the recording medium as the object by a laser beam. The present invention is also characterized in that the laser irradiation device constitutes a laser processing machine for processing the target with a laser beam.

[0009]

In the laser irradiation apparatus of the present invention, by appropriately setting the refractive index of the dielectric material constituting the dielectric multilayer film and the film thickness of each film, only the light having a wavelength within a very narrow specific range is described above. It can be reflected by a reflector. Therefore,
When the above wavelength range is set to include the wavelength of the laser beam used, the laser beam is almost completely reflected by the reflecting mirror, so the laser beam that passes through the reflecting mirror and reaches the back of the reflecting mirror. Is extremely weak. on the other hand,
Light outside the wavelength range passes through the reflecting mirror, so that when the irradiation target is colored, emits light, or is deformed by the irradiation of the laser beam, the image reflected on the mirror of the optical deflector is It can be viewed from behind the reflector through the window.

Further, in the laser irradiation apparatus of the present invention in which the window is closed by the transparent plate, the dielectric multilayer film formed on the plate reflects light in the wavelength range including the wavelength of the laser beam used. By doing so, it is possible to more reliably prevent the laser beam from leaking to the outside of the cover through the window.

Further, according to the present invention, the irradiation target of the laser beam can be observed with an extremely simple structure by directly observing the irradiation target through the window.

[0012]

EXAMPLES Next, examples of the present invention will be described. FIG.
Is a schematic sectional plan view showing a laser drawing apparatus which is an example of a laser irradiation apparatus according to the present invention, and FIG. 2 is a schematic perspective view.
The laser drawing device 20 includes a laser head 1, which is a source of a laser beam, a reflecting mirror 3, deflecting mirrors 4 and 5, a recording medium carrying unit 10, and a monitoring window 9 provided in a housing 14.
Is provided as a main component. The laser head 1 has a semiconductor laser and a converging optical system (both not shown). The semiconductor laser is 770 nm to 8 in this embodiment.
Generate laser light having a wavelength in the range of 40 nm.
The laser light generated by the semiconductor laser is emitted from the laser head 1 as a laser beam 2 which converges on the recording medium 8 arranged in the recording medium transporting section 10 by the converging optical system including a lens.

The reflecting mirror 3 is held by a holding member 3c, and is arranged at an angle of 45 ° with respect to the laser beam 2 emitted from the laser head 1 with its surface oriented obliquely laterally.
Therefore, the laser beam 2 is 90 ° by this reflecting mirror 3.
Bend right beside. The reflecting mirror 3 is formed by coating a transparent dielectric multilayer film 3b on a glass substrate 3a. The dielectric multilayer film 3b is formed by alternately arranging a dielectric layer having a high refractive index and a layer having a low refractive index with a predetermined thickness. Is selectively reflected. The reflection band is narrow, usually several tens of nm
The reflectance is close to 100% with respect to light having a wavelength within the band. In this example, 770 nm to 840 n
The dielectric multilayer film 3b so as to reflect light having a wavelength of m.
Are formed. Therefore, the laser beam 2 is almost 100% reflected by the reflecting mirror 3. This type of dielectric multilayer film total reflection mirror is commercially available, and the reflection mirror 3 can be configured using it.

The deflecting mirrors 4 and 5 reflect the laser beam 2 reflected by the reflecting mirror 3 on the recording medium 8 in the X direction and X direction.
This is for deflecting the laser beam in the Y direction orthogonal to the direction. These mirrors 4 and 5 are formed by applying a normal silver coating on a glass plate. Deflection mirror 4
Is driven by its deflection actuator 6. The deflection actuator 6 has a structure similar to that of a galvanometer, and the shaft 6a rotates by an angle corresponding to the current value supplied to the coil. The shaft 6a extends vertically downward, and the deflection mirror 4 is attached to the tip of the shaft 6a. The deflection mirror 4 is arranged at an angle of 45 ° with respect to the laser beam 2 from the reflection mirror 3 with the surface thereof obliquely laterally in a state where it is not driven by the deflection actuator 6. The laser beam 2 from the reflecting mirror 3 is reflected by the deflecting mirror 4 and enters the next deflecting mirror 5. The deflection mirror 5 is driven by the deflection actuator 7. The deflection actuator 7 also has a structure similar to that of the galvanometer, and the shaft 7a is rotated by an angle corresponding to the current value supplied to the coil. The shaft 7a extends horizontally, and the deflection mirror 4 is attached to the tip of the shaft 7a.
Is attached. When the deflection mirror 7 is not driven by the deflection actuator 7, the laser beam 2 from the mirror 4 has its optical path bent downward by 90 °.

The recording medium conveying section 10 conveys the recording medium 8 to a predetermined position for image drawing and arranges it. The laser beam 2 reflected by the deflection mirror 5 is incident on the recording medium 8 which is transported and arranged by the transport unit 10. The recording medium 8 is formed by coating a paper with a heat-sensitive material that is colored by heat. When the laser beam 2 is irradiated, the temperature of that portion rises and color is developed.

The above components are housed in a housing 14 made of an iron plate or an aluminum plate, and therefore the laser beam 2 is used.
The entire optical path of is inside the housing 14. This prevents the laser light emitted from the laser head 1 or its reflected light from leaking to the outside and adversely affecting the human body. However, a monitoring window 9 is provided in the housing 14 behind the reflecting mirror 3. A lighting fixture 12 is arranged diagonally above the recording medium transport unit 10. The recording medium 8 arranged at a predetermined position is illuminated by the lighting fixture 12.

Next, the operation will be described. The laser beam 2 emitted from the laser head 1 travels straight and is incident on the reflecting mirror 3, is almost completely reflected on the surface thereof, and its optical path is bent horizontally by 90 °. The laser beam 2 reflected by the reflecting mirror 3 is incident on the deflection mirror 4, but when the deflection mirror 4 is not driven, the optical path of the laser beam 2 is horizontally bent by 90 ° by this mirror 4. The reflected light is further reflected by the deflecting mirror 5 and is incident on the recording medium 8 arranged at a predetermined position by the recording medium conveying unit 10.

When the deflection actuator 6 drives the mirror 4, the irradiation position of the laser beam 2 on the recording medium 8 moves in the X direction. On the other hand, when the deflection actuator 7 drives the mirror 5, the laser beam 2 moves. Beam 2
The irradiation position on the recording medium 8 moves in the Y direction. Therefore, when an appropriate current is supplied to the deflection actuators 6 and 7 based on a predetermined signal, the irradiation position on the recording medium 8 moves according to the current value, and characters or figures corresponding to the signal are generated. Is drawn. The drawing result is illuminated by the luminaire 12.

Here, for example, the operator can directly visually confirm whether or not the drawing is properly performed, or to what extent the drawing has progressed. That is,
The surface of the recording medium 8 illuminated by the luminaire 12 is
First, it is reflected on the deflecting mirror 5, and the image is further reflected on the deflecting mirror 4. The operator can observe the image reflected on the mirror 4 through the reflecting mirror 3. As described above, the reflecting mirror 3 reflects light in the band of 770 nm to 840 nm, but does not reflect light of other wavelengths, that is, visible light, and is transparent to visible light. Therefore, the operator can see the image of the recording medium 8 reflected on the deflecting mirror 4 through the monitoring window 9 from behind the reflecting mirror 3.

On the other hand, the wavelength of the laser beam 2 is 770 nm
Since it is in the band of ˜840 nm, the laser beam 2 is almost completely reflected by the surface of the reflecting mirror 3. Therefore, the laser light that passes through the reflecting mirror 3 and goes out through the window 9 due to reflection or scattering is negligibly weak.
As a result, it is possible to monitor the drawing on the recording medium 8 with a simple configuration while ensuring the safety.

In the second embodiment of the present invention, in the laser drawing apparatus of FIGS. 1 and 2, the monitoring window 9 has a glass plate 9a coated with a transparent dielectric multilayer film as shown in FIG. Is blocked by. This dielectric multilayer film
This is exactly the same as the multilayer film 3b of the reflecting mirror 3. Therefore,
Light in the band of 770 nm to 840 nm is emitted from the glass plate 9
reflected by a. Therefore, even if part of the laser beam 2 passes through the reflecting mirror 3 and enters the window 9 due to reflection or scattering, the laser beam 2 is almost completely reflected by the glass plate 9a. Can be further reduced and safety can be further enhanced.

The case of the laser drawing apparatus has been described above as an example. However, when the present invention is applied to a laser processing machine, the structure thereof is basically the same as that of the laser drawing apparatus. However, in the case of a laser processing machine, the recording medium transport unit 10 and the recording medium 8 are replaced by the processing target and its fixing device. Also in this case, the metal or plastic plate in the process of being processed is illuminated by the luminaire 12, is reflected on the deflecting mirror 5, and the image reflected on the deflecting mirror 4 is viewed through the reflecting mirror 3 through the monitoring window 9. can do.

In the laser processing machine, the laser head 1 is composed of a high-power laser device and uses a high-energy laser beam. Even with such a laser beam, the reflectance of the reflecting mirror 3 is as described above. Since it is close to 100%, the reflecting mirror 3 does not absorb the energy of the laser light and becomes high in temperature, and the laser light passing through the reflecting mirror 3 is very small, so that it hardly leaks to the outside of the device. Also, safety can be secured. Further, as shown in FIG. 3, when a glass plate 9a coated with a dielectric multilayer film is attached to the monitoring window 9, the laser light leaking to the outside is further reduced, and higher safety is obtained. .

Although the reflecting mirror 3 is constructed by using the glass plate 3a and the window 9 is closed by the glass plate 9a in the above-mentioned embodiment, a plastic plate may be used instead of the glass plate 3a. Therefore, the same operation can be realized. The same effect can be achieved by using a laser-absorbing plate in which a material having an optical filter function, such as used in laser protection glasses and ND filters, is dispersed instead of the glass plate 3a.

Next, a third embodiment will be described with reference to FIG. FIG. 4 shows a schematic perspective view of a laser drawing apparatus according to the third embodiment. The same parts and members as those in the first and second embodiments are designated by the same reference numerals. In the third embodiment, the recording medium 8 to be irradiated is not directly passed through the reflecting mirror 3 but directly from the monitoring window 31. It is made visible. That is, a concave portion 33 that is recessed inward is formed in the housing 14, and a monitoring window 31 is provided at the bottom of the concave portion 33.
The recording medium 8 is made visible. Also in this case, whether or not the glass plate 9a coated with the dielectric multilayer film is attached to the monitoring window 9 is arbitrary.

When the irradiation portion is observed from the window behind the reflecting mirror through the reflecting mirror as in the first and second embodiments, the object to be irradiated is viewed from the front. On the other hand, in the case of observing the irradiation portion without passing through the reflecting mirror as in the third embodiment, the irradiation target is viewed obliquely. The former is superior for accurate inspection of whether drawing and processing are as set. In any case, when the laser light is absorbed / reflected by the window or the reflecting mirror, there is no concern that the laser light will leak to the observer side, which is safe.

[0027]

As described above, in the laser irradiation apparatus of the present invention, the refractive index of the dielectric material constituting the dielectric multilayer film and the film thickness of each film are appropriately set so as to be within a very narrow specific range. It is possible to reflect only the light having the wavelength of 5 by the reflecting mirror. Therefore, when the range of the wavelength is set to include the wavelength of the laser beam used, the laser beam is almost completely reflected by the reflecting mirror, so that the laser beam passes through the reflecting mirror and reaches the back of the reflecting mirror. The laser beam is extremely weak. On the other hand, light outside the wavelength range passes through the reflecting mirror, so by irradiation with a laser beam,
When the irradiation target develops color, emits light, or is deformed, the image reflected on the mirror of the light deflector can be observed from behind the reflecting mirror through the window.

As described above, in the laser irradiation apparatus of the present invention, the irradiation target can be observed through the reflecting mirror and the window while surely preventing the laser light from leaking out of the apparatus. Therefore, it is not necessary to incorporate a television camera into the device or install a television monitor as in the conventional case, and the device can be simplified and downsized, and the cost can be reduced.

Further, in the laser irradiation apparatus of the present invention in which the window is closed by the transparent plate, the dielectric multilayer film formed on the plate reflects light in the wavelength range including the wavelength of the laser beam used. By doing so, it is possible to more reliably prevent the laser beam from leaking to the outside of the cover through the window.

Further, according to the present invention, the irradiation target of the laser beam can be observed with an extremely simple structure by directly observing the irradiation target through the window.

[Brief description of drawings]

FIG. 1 is a schematic sectional plan view showing a laser drawing apparatus which is an example of a laser irradiation apparatus of the present invention.

FIG. 2 is a schematic perspective view showing a laser drawing apparatus which is an example of a laser irradiation apparatus of the present invention.

FIG. 3 is a schematic sectional plan view showing a laser drawing apparatus according to a second embodiment.

FIG. 4 is a schematic perspective view showing a laser drawing apparatus according to a third embodiment.

[Explanation of symbols]

 1 Laser Head 2 Laser Beam 3 Reflecting Mirror 3a Glass Substrate 3b Dielectric Multilayer Film 4, 5 Deflection Mirror 6, 7 Deflection Actuator 8 Recording Medium 9, 31 Monitoring Window 9a Glass Plate 10 Recording Medium Conveying Section 12 Lighting Fixture 14 Housing 20 Laser drawing device

Claims (8)

[Claims] 1. A laser emission source for irradiating a laser beam, an optical deflector for two-dimensionally deflecting the laser beam to irradiate an irradiation target, and an optical path of the laser beam from the laser emission source to the irradiation target. In a laser irradiation device including a cover, a reflecting mirror for reflecting the laser beam toward the light deflector is provided, the reflecting mirror is provided with a transparent substrate and a transparent dielectric multilayer film coated thereon. And a window provided in the cover portion located behind the reflecting mirror. 2. The laser irradiation apparatus according to claim 1, wherein the reflecting mirror bends the optical path of the laser beam by approximately 90 °. 3. The laser irradiation apparatus according to claim 1, wherein the substrate is made of glass or plastic. 4. The laser irradiation apparatus according to claim 1, wherein the window is closed by a plate composed of a transparent substrate and a transparent dielectric multilayer film coated on the transparent substrate. 5. The laser irradiation apparatus according to claim 4, wherein the substrate is made of glass or plastic. 6. A laser emission source for irradiating a laser beam, an optical deflector for two-dimensionally deflecting the laser beam to irradiate an irradiation target, and an optical path of the laser beam from the laser emission source to the irradiation target. A laser irradiation device comprising: a cover for covering, wherein a window is provided at a cover portion where the irradiation target can be visually recognized. 7. The laser irradiation apparatus according to claim 1, wherein the laser irradiation apparatus constitutes a laser drawing apparatus that forms an image on the recording medium as the irradiation target by a laser beam. 8. The laser irradiation apparatus according to claim 1, wherein the laser irradiation apparatus constitutes a laser processing machine that processes the irradiation target with a laser beam.