JP2004085302A - Line light generating optical system and laser marking device mounted with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for realizing a line light generating optical system capable of obtaining a line light having a large spread angle, with high efficiency, and a laser marking device on which the optical system is mounted. <P>SOLUTION: This optical system is so formed that the diameter of a light beam incident on a rod lens is larger than the diameter of its cross section, and that the incident light is reflected to the rod lens side, by arranging a reflector near the rod lens. Since the spread angle of a light, having a higher beam intensity, becomes larger than that of a light having a lower beam intensity, the light which enters the rod lens after being reflected by the reflector, acts to increase the light intensity of the line light at its end part. As a result, the beam spread angle of the line light, which can be seen with the eye, can be enlarged. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a line light generating optical system for obtaining line light from laser light, and more particularly to a line light generating optical system having a high spread angle to line light and a high conversion efficiency, and a laser marking device equipped with the same. .
[0002]
[Prior art]
When building a house, especially at the start of construction, it is essential to perform a task of setting a reference position for mounting various members and setting a level line for the positioning of member processing, that is, a blackout operation. Therefore, at the construction site, leveling was performed using instruments such as a level surveyor, multiple marks (black) were attached to the walls of the target structure, and they were connected to form a blacking line, which was used as a construction standard. .
[0003]
However, this operation must be performed by at least two people, which is very time-consuming and inefficient. In order to solve this problem, recently, the ink marking operation has been often performed efficiently using a laser marking device having a line light irradiation function. Since a laser marking device can easily perform a marking operation by one person, the laser marking device is becoming an indispensable building work tool for building work.
[0004]
The ink line is a vertical line from the floor to the wall and the ceiling, so-called “Tachi Line” or two “Tachi Lines” are simultaneously irradiated to draw a right angle line on the ceiling. ) ”Or“ Roku line ”that draws a horizontal line on a wall, or“ ground ink ”that irradiates a focused laser beam on the floor directly below the laser marking device. These lines can be obtained by transmitting the collimated laser beam through a line light generating optical element such as a rod lens.
[0005]
[Problems to be solved by the invention]
Since a method using a cylindrical rod lens is the simplest and cheapest method for obtaining line light, this method is used in most cases. FIG. 5 is an explanatory view showing the principle of generating line light using a rod lens. Reference numeral 2 denotes a rod lens, which shows a cylindrical cross section. Light beams G and F incident on the rod lens 2 from a light source (not shown) on the right side of the paper surface refract the inside of the lens 2 according to Snell's law, and then exit and spread in a fan shape. FIG. 5 should be correctly illustrated so that the outgoing light expands vertically and symmetrically with the optical axis OO as the axis of symmetry. However, since the figure is complicated, only the half that expands below the OO axis is used here. Is shown.
[0006]
The rod lens 2 has no refracting action in the longitudinal direction (the direction perpendicular to the paper surface). Therefore, the light incident on the rod lens 2 spreads in only one direction, and is converted into line light. The spread angle of the line light greatly depends on the incidence ratio to the rod lens 2. Here, the spread angle of the line light is represented by twice as large as the angle formed between the emitted light and the optical axis OO.
[0007]
In FIG. 5, the beam F has a larger incidence ratio to the rod lens 2 than the beam G. Each beam incident on the rod lens 2 is refracted according to Snell's law and exits the lens, so that the beams F and G travel as shown in FIG. 5, and the beam divergence angle increases as the incidence ratio on the rod lens 2 increases. It turns out that it becomes large.
[0008]
Therefore, in order to obtain a sufficient divergence angle of the line light, it is necessary to make the incident beam diameter 100% relative to the rod lens diameter, and the incident beam diameter is generally reduced to the rod lens diameter. On the other hand, a method of setting the ratio to more than 100% is adopted. Although this method can easily obtain a line light having a sufficient spread, it has the following two disadvantages.
[0009]
One of the drawbacks is that the beam intensity distribution of the incident beam is usually a Gaussian distribution, so that the intensity sharply decreases from the center of the beam to the outer periphery. That is, when the above-mentioned incident beam is expanded by the rod lens, the center of the obtained line light can be seen well, but the end has low intensity, so that it is hardly visible. Therefore, in principle, a sufficient divergence angle can be obtained, but the substantial divergence angle of visible light is as narrow as about 140 °.
[0010]
The second disadvantage is that if the incident beam diameter is larger than the rod lens diameter, of the incident light, those outside the rod lens do not pass through the inside of the lens, go straight on, and become bright spots on the line light. That is, irradiation is performed in the form of dots. Therefore, the dot light is usually removed by providing a light shielding portion near the rod lens. However, this method has a drawback that the conversion efficiency of converting the laser light into the line light is poor.
[0011]
SUMMARY OF THE INVENTION An object of the present invention is to solve such a conventional problem and to provide a line light generating optical system capable of obtaining line light with high efficiency and a large spread angle, and a laser marking device equipped with the optical system. It is to provide.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides an optical system having a light source comprising a semiconductor laser, a collimator lens for converting light emitted from the light source to collimated light, and a rod lens for converting the collimated light to line light. Has one feature in that a reflector that reflects collimated light from the light source toward the rod lens is disposed near the rod lens. With this configuration, the conversion efficiency of converting collimated light into line light can be increased.
[0013]
Another feature of the present invention resides in that the reflector provided near the rod lens is arranged at a predetermined angle with respect to the optical axis of the collimated light incident on the rod lens. With this configuration, the conversion efficiency can be increased, and the spread angle of the output beam can be increased.
[0014]
Still another feature of the present invention resides in that the angle between the reflection surface of the reflector and the optical axis is set in the range of 0 ° to 30 °. In this way, favorable results are obtained from both the conversion efficiency and the spread angle.
[0015]
Still another feature of the present invention is that the diameter of the light beam incident on the rod lens is selected in a range of 0 to 3 times the diameter of the rod lens. In this way, the incident light is not wasted, and the light conversion efficiency can be increased.
[0016]
Another feature of the present invention is that a laser marking device is constituted by an optical unit and a support mechanism for supporting the optical unit, wherein the optical unit includes a light source made of a semiconductor laser, and light emitted from the light source. A collimator lens that converts the collimated light into collimated light, a rod lens that converts the collimated light into line light, and a reflector provided near the rod lens, and the reflector has at least two reflection surfaces. The reflecting surfaces are arranged so as to be in contact with a part of the circumferential surface of the rod lens and to make a predetermined angle with the optical axis of the collimated light incident on the rod lens. With this configuration, it is possible to realize a laser marking device that generates line light that is extremely easy to see.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
(Embodiment 1)
FIG. 1 shows a schematic diagram of a line light generating optical system according to the present invention, and FIG. 2 shows a configuration of a main part thereof. In FIG. 1, a light beam emitted from a light source such as a laser passes through a collimator lens 30, and becomes parallel light (collimated light) having a predetermined beam diameter. This collimated light enters a rod lens 2 whose longitudinal direction is arranged perpendicular to the plane of the drawing. In this embodiment, two reflectors, that is, mirrors 10 are arranged near the rod lens 2.
As is apparent from FIG. 2, the two mirrors 10 are arranged so as to sandwich the rod lens 2 above and below the optical axis OO, and are further arranged so as to form an angle α with the optical axis OO. ing.
[0018]
The magnitude d0 of the incident light (the diameter of the incident light in a cross-sectional direction perpendicular to the longitudinal direction of the rod lens) is larger than the diameter d of the rod lens 2. Of the incident light, the beam A located farthest from the optical axis is reflected by the mirror 10. At this time, since the angle between the beam and the mirror is α, the reflection angle is also α. Next, the beam A enters the rod lens 2 and is refracted according to Snell's law, and then exits the lens. The emitted light makes an angle of φA / 2 with the optical axis.
[0019]
Further, of the incident light, the beam B located outside the rod lens 2 and closest to the rod lens 2 is reflected by the mirror 10 as shown in the figure. Also at this time, since the angle between the beam and the mirror is α, the reflection angle is also α. Next, the beam B is incident on the rod lens 2, is refracted according to Snell's law, and then exits from the lens. The emitted light makes an angle of φB / 2 with the optical axis.
[0020]
The relationship between the angles formed by the two emitted lights and the optical axis is φA / 2 <φB / 2 as shown in the figure. That is, comparing the divergence angle φA of the light beam A and the divergence angle φB of the light beam B, it can be seen that the divergence angle of the beam B located closer to the rod lens 2 is larger. This is because, when the beam enters the rod lens 2, the angle between the lens surface normal and the beam is larger for the beam B.
[0021]
In the above embodiment, the angle α was set to 10 °, and the size of the incident light was set to 1.5 times the diameter of the rod lens 2. That is, d0 = 1.5d. Further, the material of the rod lens 2 was BK7, which is a general glass material, and the ray tracing of the beam was performed, and the spread angle when the rod lens 2 was expanded to the line light by the rod lens was calculated. As a result, when the beam A corresponding to 1.5 times the rod lens diameter is incident on the rod lens 2, the beam A is incident on the rod lens 2 at an incident angle of 30 ° with respect to the normal, and finally the divergence angle φA is 82 degrees. On the other hand, when the beam B corresponding to 1.001 times the diameter of the rod lens 2 is incident on the rod lens, it is incident on the lens at an incident angle of 78 ° with respect to the normal, and finally the divergence angle φB is 188. °.
[0022]
When the beam intensities are compared, the beam intensity is higher because the beam B is located closer to the center than the beam A. That is, when the incident light outside the diameter of the rod lens is once reflected by the mirror 10 and then incident on the rod lens 2 and refracted, a beam having a higher beam intensity has a larger divergence angle. The light intensity of the part can be increased. In addition, according to the present embodiment, the conversion efficiency to the line light is 100% because all parts of the incident light are used for the generation of the line light.
[0023]
Next, a desirable range of the arrangement angle of the mirror 10 in the apparatus of the present invention will be described with reference to FIG.
Assuming that the upper mirror in the drawing is 10a and the lower mirror is 10b with respect to the rod lens 2, one of the conditions that must be considered when determining the arrangement angle α of each mirror 10a, 10b is the rod lens 2 Is not blocked by the end portions of the mirrors 10a and 10b.
[0024]
Physically, a straight line OM connecting the reflection point M on the mirror 10a and the center O of the rod lens 2, that is, when the incident light passes through the contact point S2 between the mirror 10b and the rod lens 2, the incident light is It is necessary to go straight inside and pass through the end of the mirror 10b. Mathematically, it is necessary that the relationship of ΔOS ₁ Y ₁ ≡ΔOS ₂ Y _{2 in} FIG. 6 be established when the straight line OM, that is, the incident light passes through the contact point S ₂ . When α satisfying these three conditions is obtained, α = 30 ° is obtained. Therefore, each of the mirrors 10a and 10b can form line light efficiently when the angle is greater than 0 ° and 30 ° or less with respect to a horizontal axis passing through the center of the rod lens 2.
[0025]
Next, with α set to 30 ° or less, a preferable range of the size of incident light diameter / rod lens diameter will be described with reference to FIG.
As shown, when the X axis and the Y axis are set with the center O of the rod lens 2 as the origin, a straight line S ₁ M on which the mirror 10a is arranged is expressed by the following equation (1).
y = tan α × x + R (tan α × sin α + cos α) (1)
Further, the incident light QS ₄ is in the above coordinates represented by the following equation (2).
y = tan2α · x-R ( 1 + tan 2 2α) 1/2 (2)
Here, R indicates the radius of the rod lens 2.
[0026]
The y-coordinate value of the intersection M between the above equations (1) and (2) is the incident light diameter. The y-coordinate value of M is represented by the following equation (3).
y = [tan2α · {tanα · sinα + cosα + (1 + tan 2 α) 1 /
^{2} / (tan2α-tanα)} - (1 + tan 2 α) 1/2] · R (3)
When the refractive index n of the rod lens 2 satisfies the following equation (4), the incident light diameter magnification N (= incident light diameter / rod lens diameter) is given by equation (5).
^{cos (π-2sin -1 (sinθ} / n)) · Rtan2α (1 + tan 2 2α) 1/2 / (1 + tan 2 2α) + sin (π-2sin -1 (sinθ / n
)) · (1-R) / (1 + tan 2 2α) 1/2 = -Rsinα (4)
Where θ = 2α−tan ⁻¹ {(1 / R−1) · (1 / tan2α)}
N = [tan2α · {tanα · sinα + cosα + (1 + tan 2 α) 1 /
^{2} / (tan2α-tanα)} - (1 + tan 2 α) 1/2] (5)
Now, assuming that the refractive index n of the rod lens 2 is 1.5 (the most typical glass material BK7), the relationship between the arrangement angle α of the mirror 10 and the incident light diameter / rod lens diameter is as shown in FIG. That is, if the diameter of the incident light is up to about three times the diameter of the rod lens, the incident light is effectively used, but if it is larger than that, there is a wasteful portion that does not enter the rod lens. . Therefore, the diameter of the light beam incident on the rod lens is desirably larger than 0 and three times or less the diameter of the rod lens.
(Embodiment 2)
FIG. 3 shows another embodiment of the main part of the optical system of the present invention, and shows an example in which the mirror 10 is also used as the rod lens holding member 3. That is, in the rod lens holding member 3, the tapered portion 4 is a portion for holding and housing the rod lens 2 and also serves as a mirror 10 for reflecting light. That is, the inner wall portion of the tapered portion 4 is mirror-finished by, for example, a method of forming a thin film by vacuum evaporation or plating. Further, the angle of the taper matches the reflection angle at the mirror 10. By using the rod lens holding member 3 as shown in this embodiment, it is possible to achieve both the lens holding effect and the effect of increasing the beam spread angle.
(Embodiment 3)
Next, an embodiment in which the line light generating optical system 1 of the present invention is mounted on a laser marking device will be described. As shown in FIG. 4, the laser marking device basically includes an optical system 1 for generating line light and a support mechanism 5 for keeping the optical system horizontal.
[0027]
As described above, the line light generating optical system 1 includes a laser light source, a collimator lens, a rod lens, and a reflector. When the line generating optical system 1 of the present invention is used, not only can the incident light be used 100% effectively, but also the light having a high intensity is reflected by the mirror, so that the angle of incidence on the rod lens is enlarged. As a result, it is possible to obtain a large beam divergence angle. As a result, it is possible to obtain line light having a spread angle of about 190 °.
[0028]
【The invention's effect】
As described above, in the present invention, the diameter of the light beam incident on the rod lens is made larger than the diameter of the cross section of the rod lens, and a reflector is provided near the rod lens to reflect the incident light to the rod lens side. With this configuration, it is possible to convert the incident light into 100% line light, and there is an effect that the laser light can be used very effectively. In addition, the light that enters the rod lens after being reflected by the reflector has the effect of increasing the light intensity at the end of the line light because the light with a high beam intensity has a larger divergence angle than the light with a low beam intensity. As a result, it has become possible to increase the beam spread angle of the line light that can be visually observed, as compared with the related art. For this reason, the light beam intensity is relatively averaged, and a remarkable effect that a laser marking device that generates a line light with a large beam spread angle and easily visible can be realized.
[Brief description of the drawings]
FIG. 1 is a schematic view of a line light generating optical system according to the present invention.
FIG. 2 is a schematic view of a main part showing one embodiment of a line light generating optical system of the present invention.
FIG. 3 is a schematic diagram showing one embodiment of a rod lens holding unit of the line light generating optical system of the present invention.
FIG. 4 is a schematic view showing an embodiment of a laser marking device using the line light generating optical system of the present invention.
FIG. 5 is an explanatory diagram illustrating the principle of a rod lens.
FIG. 6 is an explanatory diagram for explaining a desirable mirror arrangement angle in the present invention.
FIG. 7 is an explanatory diagram for explaining a desirable incident beam diameter in the present invention.
FIG. 8 is an explanatory diagram illustrating a relationship between a mirror arrangement angle and an incident light diameter / rod lens diameter in the present invention.
[Explanation of symbols]
1: line light generating optical system 2: rod lens 3: rod lens holding member 4: taper section 5: support mechanism section 10: optical reflector (mirror)
12: Laser marking device body 20: Laser light source 30: Collimator lens

Claims (10)

A light source composed of a semiconductor laser, a collimator lens for converting light emitted from the light source to collimated light, a rod lens for converting the collimated light to line light, and a collimator provided near the rod lens and collimated from the light source And a reflector for reflecting light toward the rod lens. A light source comprising a semiconductor laser; a collimator lens for converting light emitted from the light source to collimated light; a rod lens for converting the collimated light to line light; and at least two reflections provided near the rod lens The reflector has a predetermined angle with respect to the optical axis of the collimated light incident on the rod lens in order to reflect the collimated light from the light source toward the rod lens. A line light generating optical system, characterized in that: A light source comprising a semiconductor laser, a collimator lens for converting light emitted from the light source to collimator light, a rod lens for converting the collimator light to line light, and a reflector provided near the rod lens are provided. The reflector has at least two reflecting surfaces, each reflecting surface being in contact with a part of the circumferential surface of the rod lens and forming a predetermined angle with the optical axis of the collimated light incident on the rod lens. A line light generating optical system characterized in that a part of light emitted from the light source is reflected by the reflector, and then enters the rod lens and is converted into line light by arranging the light sources. . A light source composed of a semiconductor laser, a collimator lens that converts light emitted from the light source into collimated light, a rod lens that converts the collimated light into line light, and a holding member that holds the rod lens, The line light incident on the rod lens has a beam diameter in the direction perpendicular to the incident direction and the longitudinal direction of the rod lens larger than the diameter of the cross section of the rod lens in the same direction, and the holding member has at least two reflection surfaces. Wherein each reflecting surface is in contact with a part of the circumferential surface of the rod lens and is arranged so as to form a predetermined angle with the optical axis of the collimated light incident on the rod lens. system. 5. The line light generating optical system according to claim 2, wherein an angle between the reflection surface of the reflector and the optical axis is set to an angle in a range of 0 to 30 degrees. An optical unit; and a support mechanism for supporting the optical unit. The optical unit includes a light source including a semiconductor laser, a collimator lens configured to convert light emitted from the light source into collimated light, and the collimator. A laser marking device, comprising: a rod lens for converting light into line light; and a reflector provided near the rod lens and reflecting collimated light from the light source toward the rod lens. An optical unit; and a support mechanism for supporting the optical unit. The optical unit includes a light source including a semiconductor laser, a collimator lens configured to convert light emitted from the light source into collimated light, and the collimator. A rod lens for converting light into line light, and a reflector provided in the vicinity of the rod lens, the reflection being arranged at a predetermined angle with respect to the optical axis of the collimated light incident on the rod lens. A laser marking device characterized by comprising a body. The optical unit includes an optical unit and a support mechanism for supporting the optical unit. The optical unit includes a light source including a semiconductor laser, a collimator lens that converts light emitted from the light source into collimated light, and the collimator light. To a line light, and a reflector provided in the vicinity of the rod lens, the reflector having at least two reflecting surfaces, each reflecting surface being a circumference of the rod lens. A part of the light emitted from the light source is reflected by the reflector by being arranged so as to be in contact with a part of the surface and at a predetermined angle with the optical axis of the collimated light incident on the rod lens. A laser marking device configured to be incident on the rod lens and to convert the light into line light. 9. The laser marking device according to claim 7, wherein an angle between the reflection surface of the reflector and the optical axis is set to an angle in a range of 0 ° to 30 °. In any one of claims 1 to 4 and 6 to 8, the diameter of the light beam incident on the rod lens is in a range of 0 to 3 times the diameter of the rod lens in a direction perpendicular to the longitudinal direction of the rod lens. A line light generating optical system or a laser marking device having a value selected from the group consisting of:

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