JP2007315844A - Beam splitter and laser marker using same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make a beam splitter compact, lessen numbers of its components, make a laser marker employing the beam splitter compact and hard to be affected by environmental stresses such as temperature changes and the like, and operate the laser marker stably. <P>SOLUTION: The beam splitter 1 is composed of a prism 2 and a prism 3 each being in the form of a column whose cross-section is approximate to a right triangle, and an evaporated thin film is formed on each tilt surface, and respective tilt surfaces are bonded to each other, and an evaporated thin film is formed on a surface 23 on which light reflected by the thin film formed on a portion 22 of the tilt surface impinges just after the reflection, so as to split the light into a transmission beam and a reflection beam. The laser marker splits an incident beam into beams along three directions by using one beam splitter 1 above-mentioned, and irradiates a vertical baseline 41 with the transmission beam from the beam splitter 1. Therefore, the laser marker is made compact and hard to be affected by the environmental stresses such as the temperature changes and the like. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a beam splitter that divides a laser beam and a laser marking device including the beam splitter.

  Conventionally, as an optical system for branching light, a thin film that branches into light reflecting and transmitting light is deposited on one inclined surface of two triangular prisms. There is a beam splitter with a structure in which the two are bonded together. With the beam splitter having such a configuration, light incident on the splitter is split and irradiated in two directions on the slope.

  Furthermore, as a conventional optical system for branching light from one light source in three directions, a configuration in which the two beam splitters described above are arranged (for example, see Patent Document 1) or four triangular prisms are bonded together. A configuration using a cross prism (see, for example, Patent Document 2) is known.

  However, in the configuration as shown in Patent Document 1, since two beam splitters are provided, the number of optical parts increases, the structure becomes larger, and the number of parts increases. This increases the cost.

  Also in the configuration as shown in Patent Document 2, the number of necessary triangular prisms is increased and the number of steps for bonding these prisms is increased, which increases the cost.

  Also, conventional optical systems used in laser marking devices that irradiate horizontal and vertical reference lines and points for marking operations with laser light using a beam splitter or other optical system can be broadly divided into the following two. There are three configurations. One is a configuration in which optical systems are arranged as many as the number of lines or points to be irradiated (see, for example, Patent Document 3), and the other is to branch light from a light source into a plurality of optical paths using a branch mirror. It is the structure which irradiates a line or a point using the emitted light (for example, refer patent document 4).

  However, in the configuration as shown in Patent Document 3, the number of lines or points requires laser diodes, collimating lenses, and parts such as a case for holding them, so that the structure is enlarged, and Cost increases.

  In the configuration shown in Patent Document 4, the branch mirror can branch only into two optical paths, so that the number of parts is reduced by using two branch mirrors to irradiate two lines and one point. The structure becomes larger and the structure becomes larger. In addition, because of the structure, a line that requires relatively higher accuracy than the point to be irradiated is generated using reflected light instead of transmitted light at the branch mirror, so position fluctuation occurs due to temperature changes and the like. In this case, the line accuracy is liable to deteriorate and the handling is poor.

As described above, in the prior art, the beam splitter that divides the light of one light source in three directions and the laser marking device that irradiates in a plurality of directions are large in size, complicated in configuration, low in manufacturing efficiency, Also, handling is poor.
JP-A-5-296840 Japanese Patent Laid-Open No. 10-312034 JP 2005-10109 A JP 2002-98530 A

  The present invention solves the above-mentioned problems, and is a small beam splitter with a small number of parts, and a small laser using the beam splitter, which is less susceptible to environmental stresses such as temperature changes, and can provide stable operation. The purpose is to provide a sumi appearance device.

  In order to achieve the above object, the invention of claim 1 is composed of two prisms having a columnar shape with a substantially right-angled triangle, and the light is reflected on the inclined surface of at least one prism into light that reflects and transmits light. In the beam splitter in which a thin film is formed as described above and the inclined surfaces of these two prisms are bonded together, the light reflected by the thin film formed on the inclined surface of the light incident on the splitter hits next. A thin film that branches the light into transmitted light and reflected light is deposited on the plane of the splitter.

  According to a second aspect of the present invention, in the beam splitter according to the first aspect, a thin film for preventing reflection is deposited on the light incident surface.

  According to a third aspect of the present invention, there is provided a laser marking device comprising: a laser diode that emits a laser beam; and an optical system that receives the laser beam, branches the laser beam, and emits a laser beam for marking. A beam splitter according to claim 1 or 2 is used in the optical system.

  According to a fourth aspect of the present invention, in the laser marking device according to the third aspect, of the laser light incident from a substantially horizontal direction, the laser light transmitted through the inclined surface generates vertical reference line light. In addition, the beam splitter is arranged so that the laser beam reflected by the inclined surface irradiates the upper and / or lower part of the laser beam.

  According to a fifth aspect of the present invention, in the laser marking device according to the fourth aspect, the thin film on the inclined surface is formed by vapor deposition so that the transmittance at the wavelength of the laser beam is 60 to 90%, and the thin film on the flat surface Is formed by vapor deposition so that the transmittance at the wavelength of the laser beam is 40 to 80%, and the beam splitter is arranged so that the plane faces upward.

  According to a sixth aspect of the present invention, in the laser marking device according to the fourth aspect, the thin film on the inclined surface is formed by vapor deposition so that the transmittance at the wavelength of the laser beam is 40 to 60%. Is formed by vapor deposition so that the transmittance at the wavelength of the laser beam is 60 to 90%, and the beam splitter is arranged so that the plane faces upward.

  A seventh aspect of the present invention is the laser marking device according to the third aspect, wherein the laser beam that has passed through the inclined surface of the laser beam incident from a substantially horizontal direction generates vertical reference line light. The beam splitter is arranged so that the laser beam reflected by the inclined surface irradiates both sides.

  According to an eighth aspect of the present invention, in the laser marking device according to any one of the third to seventh aspects, the beam splitter is freely adjustable to rotate around an axis parallel to a column axis of the columnar prism. It is said that.

  According to a ninth aspect of the present invention, in the laser marking device according to any one of the third to eighth aspects, among the laser light incident from a substantially horizontal direction, the laser light transmitted through the slope is obliquely upward. An optical system that emits vertical reference laser light is configured by a reflecting mirror that reflects the light beam and a cylindrical lens that uses the laser light reflected by the reflecting mirror as vertical reference line light.

  A tenth aspect of the present invention is the laser marking device according to any one of the third to ninth aspects, wherein the laser beam passes through the upper surface and the lower surface of the housing that holds the beam splitter. This aperture is provided.

  An eleventh aspect of the invention is the laser marking device according to the ninth aspect, further comprising a horizontal reference optical system having a cylindrical lens for making the laser light emitted from the laser diode a horizontal reference line light, The horizontal reference optical system is disposed below or to the side of the optical system that emits the vertical reference laser light.

  According to the first aspect of the present invention, since the incident light can be branched in three directions by one beam splitter, the beam splitter can be reduced in size.

  According to the invention of claim 2, since the reflected light to the laser diode of the light source is reduced, the control of the laser diode driving circuit can be stabilized.

  According to the invention of claim 3, since the laser beam from one laser diode can be irradiated in one direction with one beam splitter, the number of parts can be reduced and the laser marking device can be downsized. .

  According to the fourth aspect of the present invention, since the vertical reference line is generated by the transmitted light of the beam splitter, the influence of the environmental stress on the position accuracy of the vertical reference line can be reduced.

  According to the invention of claim 5, by making the transmittance of the inclined surface where the incident laser beam first strikes and the plane where the laser beam reflected by the inclined surface strikes next to a predetermined value, When the upper point is formed and the lower point is formed by the laser beam vertically downward, the brightness of the vertical reference line, the upper point, and the lower point can be balanced.

  According to the sixth aspect of the invention, by setting the transmittance of the inclined surface on which the incident laser beam first hits and the plane on which the laser beam reflected on the inclined surface hits next to a predetermined value, When the ceiling cross line is formed, the brightness of the vertical reference line and the ceiling cross line can be balanced.

  According to the seventh aspect of the invention, the arrangement of the beam splitter can irradiate the three directions of the front and both sides with one beam splitter, so that the laser marking device can be miniaturized.

  According to the invention of claim 8, since the rotation of the beam splitter is freely adjustable, the laser light irradiated on the upper side and the lower side can be adjusted in a straight line, and the positional accuracy of the laser light can be improved.

  According to the ninth aspect of the present invention, since the optical system that emits the vertical reference laser beam is constituted by the reflecting mirror and the cylindrical lens, it is possible to irradiate vertically upward, and the inking workability is improved.

  According to the invention of claim 10, since the aperture is provided, the diameter of the laser beam forming the point light is reduced, and the visibility of the point light is improved.

  According to the eleventh aspect of the present invention, the horizontal reference optical system is disposed below or to the side of the optical system that emits the vertical reference laser beam, so that the horizontal reference optical system is a laser of the vertical reference optical system. The laser marking device can be miniaturized so as not to obstruct light.

(First embodiment)
A beam splitter according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1A shows a configuration of the beam splitter, and FIG. 1B shows a triangular prism constituting the beam splitter. In the beam splitter 1, a columnar triangular prism 2 and a triangular prism 3 having a substantially right-angled cross section are bonded to each other on the inclined surfaces 22 and 31. The material of the triangular prisms 2 and 3 is preferably transparent glass, but a resin material can also be used. And it arrange | positions so that the surface 21 may face the laser beam A side and the light reflected by the surface 22 may irradiate upward. Thin films 21a, 22a, and 23a that branch incident light into transmitted light and reflected light are deposited on the surfaces 21, 22, and 23 of the triangular prism 2, respectively.

  The transmittance representing the ratio of the amount of transmitted light to the amount of incident light varies depending on the wavelength of the light, and the transmittance of the surfaces 21, 22, and 23 will be described with reference to FIG. 2, FIG. 3, and FIG. 2 shows the transmittance of the surface 21, FIG. 3 shows the transmittance of the surface 22, and FIG. 4 shows the transmittance of the surface 23. In each figure, the horizontal axis indicates the wavelength of light, and the vertical axis indicates the transmittance. 635 nm which is the wavelength of the laser diode used as the light source of the laser marking device is indicated by a dotted line. As shown in each figure, the transmittance of the surface 21 at 635 nm is about 100%, the transmittance of the surface 22 is 80%, and the transmittance of the surface 23 is 70%.

  The branching of the laser beam in the beam splitter 1 on which a thin film is deposited will be described with reference to FIG. FIG. 5 shows a state in which the laser light emitted from the laser diode enters from the surface 21 and branches on each surface, and the ratio of each branched light when the light amount of the laser light A is 1 is attached to each laser light. It is written in the parenthesis of the symbol. The laser beam A incident on the surface 21 is transmitted through the triangular prism 2 without being reflected almost entirely. Then, 80% of the incident light on the triangular prism 2 is transmitted light B and 20% is reflected upward on the surface 22. Then, 70% of the reflected laser light becomes laser light C that passes through the surface 23, and its light quantity is 0.14. The remaining 30% of the surface 23 becomes the downward laser beam D, and its light amount is 0.06. The laser beam D is branched at the surface 22, and 0.048, which is 80% of the light amount 0.06, becomes laser light E that passes through the surface 22 and exits from the surface 32, and the light amount 0 that is 20% of the light amount 0.06. .012 is a laser beam F that reflects the surface 22 and returns in the direction of the laser diode. Therefore, assuming that the amount of laser light emitted from the laser diode is 1, the amount of each branched light is 0.8 for transmitted light B, 0.14 for upward laser light C, and downward for laser light. When E is 0.048, the laser beam F returning to the laser diode is 0.012.

  With the configuration as described above, incident light can be branched in three directions by one beam splitter, the beam splitter can be downsized, and the cost can be reduced by reducing the number of components.

  Here, the arrangement of the beam splitter 1 is turned upside down so that the reflected light from the first surface 22 irradiates downward, and the transmittance is adjusted so that the incident light is branched at the same rate as in the above configuration. The configuration described above will be described with reference to FIG. FIG. 6 shows the state of branching of the laser light when the transmittance of the surface 22 is 77.5%, the transmittance of the surface 23 is 21%, and the arrangement of the beam splitter 1 is turned upside down. The amount of each branched light in this configuration is 0.775 for the transmitted light B forward of the beam splitter 1, 0.138 for the laser light E passing through the surface 32, and 0 for the laser light C passing through the surface 23. The ratio of branching to three directions is almost the same as in the first embodiment, but the laser beam F to the laser diode is as large as 0.040, which is not suitable because the loss is large.

(Second Embodiment)
A laser marking device according to a second embodiment of the present invention will be described with reference to FIG. The laser marking device according to the present embodiment uses the beam splitter according to the first embodiment. FIG. 7 shows the appearance of the laser marking device according to the present embodiment and the usage situation in a rectangular parallelepiped room. The laser marking device according to this embodiment includes a vertical reference optical system 4 and a horizontal reference optical system 5, and the vertical reference optical system 4 includes a laser diode 6 that emits laser light for marking, A collimating lens 7 for collimating the laser beam, a beam splitter 1 for branching the collimated laser beam, a reflecting mirror 8 for reflecting the laser beam transmitted through the beam splitter 1 obliquely upward, and the reflected laser beam And a cylindrical lens 9 for line light. The laser diode 6 is placed sideways so as to emit laser light horizontally. The beam splitter 1 that branches the laser beam is held by a housing 10, and holes of apertures 11 having a diameter of 1 to 3 mm are formed on the upper and lower surfaces of the housing 10. The housing 10 is rotatable and adjustable around an axis parallel to the column axis of the columnar triangular prism. The cylindrical lens 9 has a cylindrical shape, and is arranged so that the cylinder axis is perpendicular to the laser beam and horizontal.

  The horizontal reference optical system 5 includes a laser diode 6, a collimating lens 7, and a cylindrical lens 9. The horizontal reference optical system 5 is disposed below the vertical reference optical system 4, and laser light at a lower point 44 from the vertical reference optical system 4. It has a lower point hole 12 through which it passes. The laser diode 6 of the horizontal reference optical system 5 irradiates in the same direction as the laser diode 6 of the vertical reference optical system 4, and is in front of the lower point hole 12 so as not to disturb the optical path of the lower point 44, and They are shifted in the lateral direction.

  The operation of the laser marking device according to this embodiment will be described. In the vertical reference optical system 4, the laser diode 6 emits laser light in the horizontal direction, and the laser light is collimated by the collimator lens 7 and enters the beam splitter 1. And since the beam splitter 1 which concerns on 1st Embodiment is used, the laser beam which permeate | transmitted the beam splitter 1 is reflected diagonally upward by the reflective mirror 8, spreads in fan shape in the perpendicular direction by the cylindrical lens 9, It becomes the vertical reference line 41 and irradiates the front of the room and the ceiling surface. The laser beam branched vertically upward by the beam splitter 1 is squeezed by the aperture 11 to irradiate the ceiling surface to become an upper point 43, and the laser light branched vertically downward by the beam splitter 1 irradiates the floor surface and falls down. It becomes point 44.

  In the horizontal reference optical system 5, the laser diode 6 emits laser light in the horizontal direction, and the laser light is made parallel by the collimating lens 7 and spreads in a fan shape in the horizontal direction by the cylindrical lens 9 to form a horizontal reference line 42. Irradiate the front of the room.

  In the laser marking device according to the present embodiment, the vertical reference optical system 4 is configured in this manner, so that the vertical reference line 41, the upper point 43, and the lower point 44 are formed by one laser diode 6 and one beam splitter 1. Further, the upper point 43 and the lower point 44 can be irradiated on the same line. By reducing the number of parts, the laser marking device can be reduced in size and cost, and the optical axis can be easily adjusted. Further, since the beam splitter 1 according to the first embodiment is used, the ratio of the laser light is 0.8 for the vertical reference line 41, 0.14 for the upper point 43, and 0.048 for the lower point 44. It becomes. In the normal inking operation, the light amount of the vertical reference line 41 is required to be larger than the upper point 43 and the lower point 44, and the distance to the upper point 43 is longer than that to the lower point 44. 43 requires a light amount more than the lower point 44, but in this embodiment, the brightness is balanced and the requirement is satisfied. Since the visibility of the dark part is not bad, the entire part is brightened to brighten the dark part and does not exceed class 2 of the JIS laser standard. Further, since the ratio of the laser beam returning to the laser diode 6 is as small as 0.012, there is no temperature rise due to the laser beam, the control of the laser diode driving circuit can be stabilized, and the laser beam is not wasted.

  Further, as an effect of the laser marking device according to the present embodiment, the vertical reference line 41 requiring higher positional accuracy than the upper point 43 and the lower point 44 is formed by the transmitted light of the beam splitter 1. Even if the position fluctuates due to temperature change or external force, the position of the vertical reference line 41 is not affected. In addition, the upper point 43 and the lower point 44 have a substantially circular shape with the laser beam being narrowed by the aperture 11 and are made small, so that the visibility is improved. Further, since the vertical reference line 41 is irradiated up to the vertically upper side of the laser marking device by the reflecting mirror and the cylindrical lens, workability can be improved.

  Further, since the optical path of the vertical reference line 41 can be avoided by arranging the horizontal reference optical system 5 below the vertical reference optical system 4, it is possible to reduce the size and cost of the laser marking device. it can. Further, in the normal summing-out operation, the vertical reference line 41, the upper point 43, and the lower point 44 are not necessary in the operation that requires the horizontal reference line 42, and the horizontal reference line 41 in the operation that requires the vertical reference line 41. Line 42 is not necessary. With the configuration of the present embodiment, in an operation that requires the horizontal reference line 42, the current consumption can be suppressed by turning on the laser diode 6 of the horizontal reference optical system 5 and turning off the laser diode 6 of the vertical reference optical system 4. Can do. On the contrary, in an operation requiring the vertical reference line 41, the current consumption can be suppressed by turning on the laser diode 6 of the vertical reference optical system 4 and turning off the laser diode 6 of the horizontal reference optical system 5. In addition, a laser marker that emits only the vertical reference line 41, the upper point 43, and the lower point 44; a laser marker that emits only the horizontal reference line 42; and the vertical reference line 41, the upper point 43, and the lower point 44. Three types of laser marking devices that emit all of the horizontal reference line 42 can be easily made by combining the vertical reference optical system 4 and the horizontal reference optical system 5.

  Adjustment of the optical axes of the upper point 43 and the lower point 44 irradiated by the laser marking device according to the present embodiment will be described with reference to FIGS. FIG. 8 shows an angle relationship between incident light, transmitted light, and reflected light in the beam splitter 1. In FIG. 8, the beam splitter 1 is placed so that the normal line of the surface 21 is parallel to the horizontal line 51, and the laser beam A is incident on the surface 21 with an angle H with the horizontal line 51 of θ1. The incident laser light is transmitted through the surface 22, but the triangular prism 2 and the triangular prism 3 are made of the same material, so that the angles I and Q are equal, and the refractive indexes of the surfaces 21 and 33 are the same. Angle H and angle K are also equal. Therefore, the angle K between the transmitted light B of the beam splitter 1 and the horizontal line 51 is θ1 as with the laser light A. The laser beam C directed to the upper point 43 is reflected by the surface 22, but since the angle I and the angle L are equal, the angle M and the angle N are equal, and the refractive indexes of the surfaces 21 and 23 are the same. Therefore, the angle O is equal to the angle H and becomes θ1. Further, in the laser beam E directed to the lower point 44, the angle P is equal to the angle N, and the angle J is also equal to the angle P. Therefore, the angle J is equal to the angle M, and since the refractive indexes of the surface 21 and the surface 32 are the same, the angle R is equal to the angle H and is θ1. Therefore, the angles of the laser beams C and E to the upper point 43 and the lower point 44 with the vertical line 52 are equal to the angle with the horizontal line 51 of the laser light A.

  A method of adjusting the optical axes of the upper point 43 and the lower point 44 using the above-described relationship between the angles of the laser light A and the laser lights C and E will be described with reference to FIG. FIG. 9 shows a state of adjusting the angle of the beam splitter 1. From the relationship of FIG. 8 described above, the laser light that irradiates the upper point 43 and the lower point 44 is not in a straight line unless the laser light A and the normal of the surface 21 are parallel. At this time, by rotating and adjusting the housing 10 holding the beam splitter 1 around an axis parallel to the column axis of the columnar triangular prism 2, the incident laser beam and the normal of the surface 21 are made parallel. The laser beams that irradiate the upper point 43 and the lower point 44 are aligned. In this way, the optical axis adjustment of the upper point 43 and the lower point 44 can be facilitated.

(Third embodiment)
A beam splitter and a laser marking device according to a third embodiment of the present invention will be described with reference to FIGS. The laser marking device according to the present embodiment irradiates the ceiling cross line in place of the upper point 43 in the laser marking device according to the second embodiment, and is applied to the surfaces 22 and 23 of the beam splitter 1. The transmittance is different, and a cylindrical lens is provided on the top of the housing 10. FIG. 10 shows a state in which the laser light emitted from the laser diode 6 enters from the surface 21 of the beam splitter 1 and branches at each surface, and the ratio of each branched light when the amount of incident light is 1 is shown in parentheses. It is described in. The transmittance of the surface 22 is 50%, and the transmittance of the surface 23 is 90%. The forward laser beam B has a light quantity of 0.5, the upward laser light C has a light quantity of 0.45, and the downward laser light E has a light quantity of 0.025.

  FIG. 11 shows the appearance of the laser marking device according to the present embodiment and the usage situation in a rectangular parallelepiped room. The laser marking device according to the present embodiment includes a cylindrical lens 9 on the optical path of the laser beam at the upper part of the casing 10 of the vertical reference optical system 4, and its column axis is emitted horizontally from the laser diode 6. It arrange | positions so that it may become parallel to light. Laser light emitted from the laser diode 6 enters the beam splitter 1 and is divided into transmitted light, upward branched light, and downward branched light. The transmitted light has a light quantity of 0.5 and becomes a vertical reference line 41, and the laser light branched upward spreads in a fan shape by the cylindrical lens 9 with a light quantity of 0.45 and is a ceiling cross line 45 perpendicular to the vertical reference line 41. Thus, the laser beam branched downward becomes the lower point 44 when the light amount is 0.025. With this configuration, the vertical reference line 41 and the ceiling cross line 45 have the same brightness, and a laser beam suitable for downlight installation work or the like can be emitted.

(Fourth embodiment)
A laser marking device according to a fourth embodiment of the present invention will be described with reference to FIGS. The laser marking device according to the present embodiment changes the orientation of the arrangement of the beam splitter 1 in the laser marking device according to the second embodiment, and does not irradiate the upper point 43 and the lower point 44, so This is a laser marking device that emits light. FIG. 12 shows the appearance of the vertical reference optical system 4 of the laser marking device according to the present embodiment and the use situation in a rectangular parallelepiped room. FIG. 13A shows a plan view seen from the direction of arrow U in FIG. 12, and FIG. 13B shows a front view seen from the direction of arrow V in FIG.

  The configuration of the laser marking device according to this embodiment will be described. The laser marking device according to the present embodiment is arranged so that the surface 23 of the beam splitter 1 faces the arrow W direction in FIG. 12 and the surface 32 faces the arrow X direction. 8b and 8c and cylindrical lenses 9b and 9c are provided. The beam splitter 1 is rotatable and adjustable about an axis parallel to the column axis of the columnar triangular prism so that the optical axis can be adjusted. The reflecting mirrors 8b and 8c are installed so that the reflecting surfaces are obliquely upward so as to reflect the horizontal laser light obliquely upward, and the cylindrical lenses 9b and 9c are configured so that the cylindrical axes of the laser light emitted from the laser diode 6 are emitted. It is arranged to be parallel to the direction. The laser light emitted from the laser diode 6 and collimated by the collimating lens 7 is split into transmitted light and reflected light in the directions of the arrow W and X in FIG. Then, the branched light in the direction of arrow W is reflected obliquely upward by the reflecting mirror 8b, spreads in a fan shape by the cylindrical lens 9b, becomes line light, irradiates the left side surface and ceiling surface of the room, and becomes the left vertical reference line 46. The branched light in the direction of the arrow X is reflected obliquely upward by the reflecting mirror 8c, spreads in a fan shape by the cylindrical lens 9c, becomes line light, irradiates the indoor right side surface and the ceiling surface, and becomes the right vertical reference line 47. The transmittance of each surface of the beam splitter 1 may be set to an appropriate value. Since one laser diode 6 and one beam splitter 1 can irradiate the vertical reference line 41, the left vertical reference line 46, and the right vertical reference line 47, the laser marking device can be downsized and the cost can be reduced.

  The present invention is not limited to the configurations of the various embodiments described above, and various modifications can be made without departing from the spirit of the invention. For example, a semi-cylindrical lens may be used without using the cylindrical lens 9. Further, the transmittance of each surface of the beam splitter 1 can be set to a value suitable for the purpose of use.

(A) is a block diagram of the beam splitter which concerns on the 1st Embodiment of this invention, (b) is a block diagram of the triangular prism which comprises the beam splitter. The transmission characteristic figure of the surface 21 of the beam splitter which concerns on the 1st Embodiment of this invention. The transmission characteristic figure of the surface 22 of the beam splitter. The transmission characteristic figure of the surface 23 of the beam splitter. The optical path schematic of the beam splitter. The optical path schematic diagram at the time of the arrangement direction change of the beam splitter. The external view of the laser marking device which concerns on the 2nd Embodiment of this invention. The optical path schematic diagram of the beam splitter of the laser marking device. Angle adjustment diagram of the beam splitter of the laser marking device. The optical path schematic of the beam splitter which concerns on the 3rd Embodiment of this invention. External view of a laser marking device using the beam splitter. The external view of the vertical reference | standard optical system of the laser marking device which concerns on the 4th Embodiment of this invention. (A) is a plan view of the vertical reference optical system of the laser marking device, and (b) is a front view of the vertical reference optical system of the laser marking device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Beam splitter 2, 3 Triangular prism 6 Laser diode 8 Reflective mirror 9 Cylindrical lens 10 Case 11 Aperture 21 Surface (incident surface)
22, 31 plane (slope)
23 planes
41 Vertical reference line 42 Horizontal reference line

Claims (11)

The prism is composed of two prisms having a substantially right triangle in cross section, and a thin film is vapor-deposited on the slope of at least one of the prisms so as to be branched into light reflected and transmitted through the slope, and the two prisms. In the beam splitter that bonds the slopes of
Of the light incident on the splitter, the light reflected by the thin film formed on the inclined surface is formed by vapor deposition on the plane of the splitter where the light is split next into transmitted light and reflected light. And beam splitter.   2. The beam splitter according to claim 1, wherein a thin film for preventing reflection is deposited on the light incident surface. In a laser marking device comprising: a laser diode that emits laser light; and an optical system that makes the laser light incident, branches the laser light, and emits laser light for marking.
A laser marking device using the beam splitter according to claim 1 or 2 in the optical system.   Of the laser light incident from a substantially horizontal direction, the laser light transmitted through the slope becomes light for generating vertical reference line light, and the laser light reflected by the slope is both vertically upward and vertically downward. The laser marking device according to claim 3, wherein the beam splitter is arranged so as to irradiate any one of them.   The thin film on the inclined surface is formed by vapor deposition so that the transmittance at the wavelength of the laser beam is 60 to 90%, and the thin film on the plane is formed so that the transmittance at the wavelength of the laser beam is 40 to 80%. The laser marking device according to claim 4, wherein the beam splitter is disposed so as to be vapor-deposited and the plane faces upward.   The thin film on the inclined surface is formed by vapor deposition so that the transmittance at the wavelength of the laser beam is 40 to 60%, and the thin film on the plane is formed so that the transmittance at the wavelength of the laser beam is 60 to 90%. The laser marking device according to claim 4, wherein the beam splitter is disposed so as to be vapor-deposited and the plane faces upward.   Of the laser light incident from a substantially horizontal direction, the laser light transmitted through the inclined surface becomes light for generating vertical reference line light, and the laser light reflected by the inclined surface irradiates both sides. 4. The laser marking device according to claim 3, wherein the beam splitter is arranged.   The laser marking device according to any one of claims 3 to 7, wherein the beam splitter is freely rotatable around an axis parallel to a column axis of the columnar prism. Of the laser light incident from a substantially horizontal direction, a reflecting mirror that reflects the laser light transmitted through the inclined surface obliquely upward;
9. An optical system that emits vertical reference laser light is configured by a cylindrical lens that uses the laser light reflected by the reflecting mirror as vertical reference line light. The laser marking device according to claim 1.   The laser marking according to any one of claims 3 to 9, wherein an aperture having a diameter of 1 to 3 mm through which a laser beam passes is provided on an upper surface and a lower surface of a housing that holds the beam splitter. vessel. A horizontal reference optical system having a cylindrical lens for making laser light emitted from the laser diode a horizontal reference line light;
10. The laser marking device according to claim 9, wherein the horizontal reference optical system is disposed below or on the side of the optical system that emits the vertical reference laser beam.

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