JP2003290941A - Laser marker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure of a laser marker that can provide a laser beam energy density sufficient for marking a marking object by using a comparatively low output LD (semiconductor laser) as a light source. <P>SOLUTION: Laser beams emitted from LDs 1a, 1b are each made to be a near parallel beam by collimator lenses 2a, 2b, subjected to correction of removing the influence of astigmatic difference of the LDs 1a, 1b by cylindrical convex lenses 3a, 3b, and then made incident on the original light-emitting surfaces 4a, 4b of a polarizing beam splitter 4. After that, the laser beams are synthesized into one laser beam for the purpose of adding up the energy densities, and then emitted from the original light incident surface 4c. This resultant laser beam is reflected by a galvano mirror 5 rotating for scanning, converged on and emitted to an object 7 by means of an equidistant projecting lens 6. Thus, the marking is performed on the object 7. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser marker that performs marking such as printing by focusing laser light emitted from a semiconductor laser by an optical system and irradiating the object to be marked.

[0002]

2. Description of the Related Art Semiconductor lasers (hereinafter abbreviated as LD)
In general, since the output intensity is smaller than that of other gas lasers and solid-state lasers, in order to use it as a light source of a laser marker, it is indispensable to use a high-power LD and further focus it on a minute spot. . Therefore, as a high-power LD, a broad area type LD having a large active region area is used as a light source, and a laser marker configuration is proposed in which laser light emitted from this is focused into a minute spot by an optical system.

[0003]

However, in the broad area type LD, the stripe width of the active region is a normal L.
Since it is longer than D, the emitted laser light is LD
Is a long ellipse that is long in the direction perpendicular to the active layer. Also, the astigmatic difference is large. Therefore, a general optical system cannot obtain a small spot light and requires a special optical system.
There was a problem that it would be costly. On the other hand, there is a problem that even if an ordinary low-power LD is used, it is not possible to obtain an energy density of laser light sufficient for marking an object to be marked.

Therefore, an object of the present invention is to provide L of a relatively low output.
An object of the present invention is to provide a structure of a laser marker that can obtain an energy density of laser light sufficient for marking an object to be marked without using a special optical system while using D as a laser light source.

[0005]

In order to solve the above-mentioned problems, according to the present invention, two semiconductor lasers and two laser lights emitted from the two semiconductor lasers are made to be substantially parallel lights. The collimator lens and each of the laser beams that have passed through the two collimator lenses are made incident from the original light emitting surface, and are combined into one laser beam so that the respective energy densities of the laser beams are added, and originally, Marking is performed by concentrating the laser light emitted from the original light incident surface of the polarization beam splitter and irradiating it to the marking target. The structure of the laser marker is adopted.

[0006]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the present invention will be described below with reference to FIG. FIG. 1 shows the configuration of the optical system of the laser marker of the embodiment.

In the configuration of the optical system of the laser marker shown in FIG. 1, two semiconductor lasers (hereinafter also abbreviated as LD) 1
On the optical axes of a and 1b, two collimator lenses 2a and 2b and a cylindrical convex lens 3a and 3b are arranged in this order.
b, a polarizing beam splitter 4, a galvano mirror 5 which is a movable mirror, and an equidistant projection lens (hereinafter abbreviated as fθ lens) 6 are arranged, and a marking target (hereinafter referred to as a target) on an extension line of its optical axis. 7) is arranged.

The LDs 1a and 1b are arranged such that their optical axes are orthogonal to each other, and are rotatably provided about their respective optical axes, and their positions in the direction of rotation about their respective optical axes are set. It can be set variably. It should be noted that the LDs 1a and 1b are not high output type such as broad area type, but relatively low output type.

The collimator lenses 2a and 2b are LD1
The laser beams emitted from a and 1b are positioned so as to be substantially parallel light. Where LD1
Each of the laser light emitted from a and 1b is LD
Due to the astigmatic difference between 1a and 1b, laser light emitted in the horizontal direction along the active layer of the LDs 1a and 1b (hereinafter referred to as horizontal laser light) and laser light emitted in the direction perpendicular to the active layer (hereinafter , Vertical surface direction laser light), the apparent emission position is shifted in the optical axis direction. As a result, the horizontal plane laser beam and the vertical plane laser beam are deviated in angle with respect to the optical axis. That is, they do not form the same angle at the same distance from the optical axis. Therefore, with respect to each of the laser beams that have passed through the collimator lenses 2a and 2b, the angle between the horizontal plane laser beam and the vertical plane laser beam is different from the optical axis. Then, by adjusting the positions of the collimator lenses 2a and 2b,
For example, even if vertical plane direction laser light is parallel light parallel to the optical axis, horizontal plane direction laser light does not become parallel light, and if it is left as it is, it is possible to focus the laser light on one point to obtain a minute spot light. I can't.

Therefore, the cylindrical convex lens 3a,
3b is provided. Cylindrical convex lens 3a,
Reference numeral 3b corrects each of the laser beams that have passed through the collimator lenses 2a and 2b so as to eliminate the angular deviation of the laser beams from the horizontal plane laser beam and the vertical plane laser beam due to the astigmatic difference of the LDs 1a and 1b. , The horizontal plane laser light and the vertical plane laser light emitted through the cylindrical convex lenses 3a and 3b are arranged at the same distance and the same angle from the optical axis. For example, the horizontal plane laser light is also the vertical plane laser. The light should also be parallel light parallel to the optical axis.

Next, the polarization beam splitter 4 is originally used to separate one laser beam incident from the light incident surface 4c into two polarization directions orthogonal to each other, and the two separated laser beams. Light is emitted from the light emitting surfaces 4a and 4 respectively.
It is emitted from b. However, in this embodiment,
The polarization beam splitter 4 is arranged so that the light incident surface and the light emitting surface are opposite to each other, and the collimator lens 2a,
Each of the laser beams that have passed through 2b and the cylindrical convex lens 3a, 3b is incident from each of the original light emitting surfaces 4a, 4b of the polarization beam splitter 4, and is combined into one laser beam so that their respective energy densities are added. The light is combined and emitted from the original light incident surface 4c.

Here, as is generally the case, L
Since the laser lights emitted from D1a and 1b are linearly polarized, the polarization directions of the respective laser lights can be variably set by rotating the LDs 1a and 1b about their respective optical axes. 4 can be adjusted to match the respective polarization directions of the original light emitting surfaces 4a and 4b.

Since the original light emitting surfaces 4a and 4b have their polarization directions orthogonal to each other, the cylindrical convex lenses 3a and 3b are arranged so as to correspond thereto.
That is, the cylindrical convex lenses 3a and 3b are arranged such that the directions of the respective generatrices are perpendicular to the original polarization directions of the light emitting surfaces 4a and 4b.

Next, the galvano mirror 5 is driven (rotated) for scanning by the laser light, and reflects the laser light emitted from the original light incident surface 4c of the polarization beam splitter 4. As a result, the laser light is swung in one direction on the object 7 for scanning.

Next, the fθ lens 6 is connected to the galvano mirror 5
The laser beam reflected by the object 7 is focused on the object 7, and the scanning angle (rotation angle) of the galvano mirror 5
The scanning line of the laser beam on the object 7, that is, the length of the marked line is proportional.

Next, the operation at the time of marking with the above configuration will be described. At the time of marking, LD1a, 1b
Are driven, and laser light is emitted from each. The laser beams are collimator lenses 2a and 2b, respectively.
After being made into a substantially parallel light by the cylindrical convex lens 3
As described above, a and 3b are corrected so as to eliminate the angle deviation of the horizontal plane laser beam and the vertical plane laser beam with respect to the optical axis due to the astigmatic difference of the LDs 1a and 1b. For example, both are parallel rays parallel to the optical axis. To be

Further, each of the laser beams is made incident from the original light emitting surfaces 4a and 4b of the polarization beam splitter 4, and combined into one laser beam so that the respective energy densities of the laser beams are added together, and originally, Is emitted from the light incident surface 4c. The combined laser beam is reflected by the galvanometer mirror 5 that is being driven (rotated), is swung in the scanning direction, passes through the fθ lens 6, is focused on the object 7, and is scanned in one direction. To do. As a result, marking such as printing is made on the object 7.

By the action of the cylindrical convex lenses 3a and 3b relating to the correction of the astigmatic difference, the laser light emitted from the original light incident surface 4c of the polarization beam splitter 4 is a horizontal laser light and a vertical laser light. The emission angles of light are the same at the same distance from the optical axis. Therefore, the laser light can be focused on one minute spot by the fθ lens 6 for marking.

According to this embodiment as described above, the LD1
The two laser beams emitted from a and 1b are combined into one laser beam by the polarization beam splitter 4 so that their respective energy densities are added, and marking is performed by the combined laser beam. Even if the laser light sources LD1a and 1b having a relatively low output are used, the energy density of the laser light sufficient for marking the object 7 can be obtained, and the marking can be performed without any trouble. Further, unlike the case of using the broad area type LD, a special and expensive optical system is not required, and the laser marker can be constructed at low cost.

In the above-described configuration of the present embodiment, if the astigmatic difference between the LDs 1a and 1b is small and the influence thereof is small enough to focus the laser light on a minute spot, a cylindrical convex lens is used. Three
It is possible to omit a and 3b.

[0021]

As is apparent from the above description, according to the present invention, in the laser marker, the two laser beams emitted from the two semiconductor lasers have their energy densities added together by the polarization beam splitter. As described above, since the laser light is combined into one laser beam and the combined laser light is used for marking, even if a relatively low-power semiconductor laser is used as a laser light source, it is sufficient to mark an object to be marked. The energy density of laser light can be obtained, and marking can be performed without any trouble. Further, unlike the case of using a high output broad area type semiconductor laser, it is possible to obtain an excellent effect that a laser marker can be inexpensively constructed without requiring a special optical system.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a configuration of an optical system of a laser marker according to an embodiment of the present invention.

[Explanation of symbols]

1a, 1b Semiconductor laser (LD) 2a, 2b Collimator lens 3a, 3b Cylindrical convex lens 4 Polarizing beam splitter 5 galvo mirror 6 Equidistant projection lens (fθ lens) 7 Marking target

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2C362 AA10 AA11 AA26 AA43 AA49                       AA52 BA17 BA84 BA86 CB67                       DA03                 4E068 AB00 CA06 CB05 CB10 CD02                       CD05 CD14 CE03                 5F073 AB25 AB27 AB29 BA09 FA30

Claims (4)

[Claims] 1. Two semiconductor lasers, two collimator lenses that make the laser beams emitted from the two semiconductor lasers substantially parallel, and the laser beams that have passed through the two collimator lenses, respectively. It has a polarization beam splitter that is arranged so as to be incident from the light emission surface of the laser light, be combined into one laser light so that the respective energy densities of the laser light are added, and then be emitted from the original light incident surface. A laser marker characterized in that marking is performed by focusing laser light emitted from the original light incident surface of the polarization beam splitter and irradiating it onto a marking target. 2. The semiconductor laser, which is disposed between each of the two collimator lenses and the polarization beam splitter, and which has an astigmatic difference of the semiconductor laser with respect to each of the laser beams that have passed through the two collimator lenses. 2. Two cylindrical lenses are provided to correct the laser light in the horizontal plane direction along the active layer and the angle of the laser light in the direction perpendicular to the active layer with respect to the optical axis. Laser marker described in. 3. A movable mirror, which is driven for scanning by the laser light emitted from the original light incident surface of the polarization beam splitter and reflects the laser light, and a marking of the laser light reflected by the movable mirror. The laser marker according to claim 1 or 2, further comprising an equidistant projection lens that focuses on an object. 4. The two semiconductor lasers are rotatably provided around their respective optical axes, and the rotation allows the polarization directions of the laser beams emitted by the respective semiconductor lasers to be variably set. The laser marker according to any one of claims 1 to 3, wherein the laser marker is formed.