JP4976892B2 - Laser marker - Google Patents

Description

The present invention is a laser marking device, a laser marker for machining such as printing by irradiating a laser beam to the workpiece.

  The laser processing apparatus scans a laser beam within a predetermined region and irradiates the surface of a processing target (work) such as a component or product with a laser beam to perform processing such as printing or marking. An example of the configuration of the laser processing apparatus is shown in FIG. The laser processing apparatus shown in this figure includes a laser control unit 901, a laser output unit 902, and an input unit 904. The excitation light generated by the laser excitation unit 910 of the laser control unit 901 is transmitted to the laser output unit 902 and irradiated to the solid-state laser medium 921 constituting the resonator by the laser resonance unit 920 to cause laser oscillation. The laser oscillation light is emitted from the emission end face of the solid-state laser medium 921, the beam diameter is enlarged by the beam expander 936, reflected by the optical member, and guided to the laser light scanning system 930. The laser beam scanning system 930 reflects the laser beam and polarizes the laser beam in a desired direction, and the laser beam LB output from the work area condensing unit 940 is scanned on the surface of the workpiece W to perform processing such as printing.

As a configuration for exciting the solid-state laser medium, a so-called end-pumping one-way excitation method is known in which excitation light for exciting the solid-state laser medium is incident only from one end face to be excited, and laser light is emitted from the other end face. It has been. In addition, a two-way excitation system that irradiates excitation light from the front and rear end faces of the solid-state laser medium has been proposed. In the bi-directional excitation, in addition to a configuration in which a semiconductor laser (Laser Diode: LD) as an excitation light source is disposed on each end face, excitation light from a single LD 928 is transmitted to an optical fiber 932 as disclosed in FIG. Is known, and is pumped from both end faces of the solid-state laser medium 921 and output from the output coupler 918 (see, for example, Patent Document 1).
Japanese National Patent Publication No. 11-505376

  According to such bi-directional excitation, the excitation light is dispersed and applied from the two end faces, so that the amount of excitation light at each end face can be suppressed, and the generation of the thermal lens, the ignition lens effect, and the like can be suppressed. However, in recent years, there has been a demand for further improvement of the output of the laser processing apparatus, and thus further improvement of the output of the LD is required. As a result, it is necessary to increase the amount of input excitation light from each end face even in the bi-directional excitation, and there is a possibility that the thermal lens, the igniting lens effect, thermal birefringence or heat damage may occur on each end face.

The present invention has been made in view of such conventional problems, and the main object of the present invention is to suppress or alleviate the occurrence of a thermal lens or the like in two-way excitation, thereby improving reliability. It is to provide a laser marker.

Means for Solving the Problems and Effects of the Invention

To achieve the above object, a laser marker according to the first invention, the excitation for transmitting a laser control unit for generating excitation light, the excitation light generated by the laser control unit as hereinafter described laser output unit a laser marker comprising an optical transmission medium, and a laser output unit including a laser beam scanning system for scanning the laser beam generated by the laser oscillation based on the excitation light transmitted by the excitation light transfer medium, the laser output unit is extended in one direction, a crystalline solid state laser medium having two end faces, the excitation light transmitted by the excitation light transfer medium was poured from both end surfaces is intended to cause laser oscillation And a first end surface constituting the incident surface of the excitation light and a second end surface constituting the incident surface of the excitation light and the extraction surface of the excitation light as the end surface. Solid state laser medium If branches the excitation light transmitted by the excitation light transfer medium, the two second excitation light traveling in the first excitation light and second branch path travels first branch path, the solid-state laser medium from the first branch path first the end face of the first excitation light of the excitation light, the second excitation light from the second branch path to a second end surface, the branch means first excitation light Ru is respectively incident to be larger than the second excitation light A first dichroic mirror that is disposed on the first branch path so as to face the first end face, transmits the excitation light, and reflects the laser oscillation light toward the first end face, and a second facing the second end face. A second dichroic mirror that is disposed on the branch path and transmits the excitation light and reflects the laser oscillation light toward the output mirror described later; and a position that does not interfere with the branch path, and is unidirectional from the second dichroic mirror. It is located at a distance in a direction substantially orthogonal An output mirror for outputting the light reflected by the second dichroic mirror, disposed between the output mirror and the second dichroic mirror, comprising a Q switch for controlling ON / OFF of the laser output, a solid-state laser The distance between the medium and the first dichroic mirror is shorter than the distance between the second dichroic mirror and the output mirror, and the first excitation light incident on the first end surface is incident on the second end surface. It can comprise so that it may become more than 2nd excitation light . As a result, the ratio of the pumping light in the two-way pumping is regulated so that the exit surface side becomes lower, thereby mitigating the influence caused by the generation of the thermal lens and suppressing the deterioration of the quality of the laser output light. The operation can be stabilized.

The laser marker according to the second invention, the branch means, the ratio for splitting incident light into the first excitation light and second excitation light, approximately 2: can be set to 1: 1 to approximately 4. As a result, a highly efficient operation with a reduction in laser output minimized can be obtained.

Laser marker according to still embodiment, the solid-state laser medium is a substantially rectangular parallelepiped shape, the end surfaces 5mm × 5mm or less, set the length below 18 mm.

Furthermore laser marker according to the third invention, the solid-state laser medium Nd: can a YVO ₄ crystal.

Furthermore laser marker according to another embodiment, a Nd concentration of the solid-state laser medium can than 1%. This enables highly efficient laser oscillation.

Furthermore laser marker according to the fourth invention, the reflectivity of the output mirror may be 30% to 70%.

Furthermore laser marker according to another embodiment, the excitation light source can include a semiconductor laser. Thus, maintenance with high efficiency easy laser marker can be realized.

Furthermore laser marker according to the fifth invention, the average output of the semiconductor laser as an excitation light source can be a more 10 W. Even when such a high-power semiconductor laser is used, generation of a thermal lens can be suppressed and stable laser output light can be obtained.

Furthermore laser marker according to another embodiment, the exciting light emitted from the semiconductor laser can unpolarized light. By making non-polarized light, it is not necessary to consider the change in polarization state, which is advantageous in design.

Furthermore laser marker further according to the sixth invention, it is disposed on the opposite side of the solid-state laser medium on the first branch path to face the first dichroic mirror, a first excitation light of the excitation light transmitted through the first dichroic mirror There is the spot diameter at the time of being irradiated to the first end surface, a first condensing lens causes condensing the excitation light to be smaller than TEM ₀₀ mode of the solid-state laser medium, a to face the second dichroic mirror 2 disposed opposite the solid-state laser medium on the branch path, the spot diameter when the second excitation light of the excitation light transmitted through the second dichroic mirror is irradiated on the second end face, than TEM ₀₀ mode of the solid-state laser medium also and a second condensing lens causes condensing the excitation light so as to reduce, to the first end surface of the solid-state laser medium, small spot diameter than TEM ₀₀ mode of the solid-state laser medium Excitation light is turned on, and, on the second end surface of the solid-state laser medium, solid excitation light small spot diameter than the laser medium TEM ₀₀ mode is turned can be configured to the solid-state laser medium is excited. Thereby, in two-way excitation, the spot diameter of the excitation light can be made smaller than that of the TEM ₀₀ mode of the solid-state laser medium, and high efficiency can be achieved.

Furthermore laser marker according to the seventh invention, the laser output unit is further the first pumping light or the second pumping light branched by the branching unit, a first reflecting mirror for reflecting substantially vertically, the first reflecting mirror The reflected light reflected or the second excitation light or the first excitation light branched by the branching means is further reflected in a substantially vertical direction, and the reflected light reflected by the second reflection mirror is substantially perpendicular. A branch path constituted by the first branch path and the second branch path is formed into a rectangular shape by the branching means, the first reflection mirror, the second reflection mirror, and the third reflection mirror. The solid-state laser medium and the first and second dichroic mirrors are arranged on any one side of the rectangular shape, and are any one of the rectangular vertices, and any of the rectangular shapes forming the vertices On the extension of the side Excitation light from the excitation light source can be arranged to be incident. As a result, the bifurcated excitation bifurcation path can be formed in a rectangular shape, the laser resonator can be arranged on one of the sides, and the incident position of the excitation light from the excitation light source can be arranged at one of the rectangular vertices. As a result, the branch path for bi-directional excitation of the solid-state laser medium can be greatly simplified, making it compact and increasing the degree of freedom in layout.

Furthermore laser marker further according to the eighth invention, it is arranged between the branching means and pumping light transfer medium and the excitation light coupling means for optically coupling a second dichroic mirror and the output mirror, the laser oscillation light And an aperture for shaping. Thereby, the optical system of a laser resonator can be adjusted appropriately.

Furthermore laser marker according to the ninth invention, a laser beam scanning system of the laser output unit is provided with an exit lens and the incident lens, the optical axis of the incident lens and the exit lens in the optical axis of the laser beam emitted from the laser resonator portion A Z-axis scanner capable of adjusting the focal length of the laser light by changing the relative distance between the incident lens and the outgoing lens along these optical axes in a state of matching, and the laser light transmitted through the Z-axis scanner, X-axis scanner or Y-axis scanner for scanning in the X-axis direction or Y-axis direction, and Y-axis for scanning laser light scanned by the X-axis scanner or Y-axis scanner in the Y-axis direction or X-axis direction A scanner or an X-axis scanner. With such a laser beam scanning system, the laser output light obtained by the laser resonator can be scanned three-dimensionally within the work area.

Furthermore, a solid-state laser resonator according to another embodiment includes a pumping light source that generates pumping light, and a crystalline solid-state laser medium that extends in one direction and has two end faces. Excitation light from both end faces to cause laser oscillation, and the end face is a first end face that constitutes the incident face of the excitation light and the opposite side of the first end face, A solid-state laser medium having an incident surface and a second end surface constituting a pumping light extraction surface; and pumping light output from the pumping light source is branched into two paths, a first branch path and a second branch path; the first excitation light of the excitation light to the first end surface of the solid-state laser medium 1 branch path, a second pumping light from the second branch path to a second end surface, so that the first excitation light is larger than the second excitation light Branching means for making each incident on the first end face A first dichroic mirror that is disposed on the first branch path and transmits the excitation light and reflects the laser oscillation light to the first end face side, and is disposed on the second branch path so as to face the second end face. And a second dichroic mirror that reflects the laser oscillation light toward the output mirror, which will be described later, and a position that does not interfere with the branch path and is substantially orthogonal to the laser oscillation light, And an output mirror for outputting the reflected light, and the first pumping light of the pumping light is input to the first end face of the solid-state laser medium, and the second pumping light is input to the second end face to pump the solid-state laser medium. Can be configured. As a result, the ratio of the pumping light in the two-way pumping is regulated so that the exit surface side becomes lower, thereby mitigating the influence caused by the generation of the thermal lens and suppressing the deterioration of the quality of the laser output light. The operation can be stabilized.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the embodiments shown below are intended to illustrate the laser marker for embodying the technical idea of the present invention, the present invention does not specify the laser marker to the following. Further, the present specification by no means specifies the members shown in the claims to the members of the embodiments. In particular, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in the embodiments are not intended to limit the scope of the present invention unless otherwise specified, and are merely explanations. It is just an example. Note that the size, positional relationship, and the like of the members shown in each drawing may be exaggerated for clarity of explanation. Furthermore, in the following description, the same name and symbol indicate the same or the same members, and detailed description thereof will be omitted as appropriate. Furthermore, each element constituting the present invention may be configured such that a plurality of elements are constituted by the same member and the plurality of elements are shared by one member, and conversely, the function of one member is constituted by a plurality of members. It can also be realized by sharing.

  In this specification, the connection between the laser processing apparatus and computers, printers, external storage devices and other peripheral devices for operation, control, input / output, display, and other processing connected thereto is, for example, IEEE 1394, RS- 232x, RS-422, RS-423, RS-485, USB, PS2, etc., serial connection, parallel connection, or 10BASE-T, 100BASE-TX, 1000BASE-T, etc. I do. The connection is not limited to a physical connection using a wire, but may be a wireless connection using radio waves such as IEEE802.1x, OFDM, etc., Bluetooth (registered trademark), infrared rays, optical communication, or the like. Further, a memory card, a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, or the like can be used as a recording medium for storing observation image data or setting data.

In the following embodiments, a laser marker will be described as an example of a laser processing apparatus embodying the present invention. However, in this specification, the laser processing apparatus can be used in general for laser application equipment regardless of its name, for example, laser processing such as a laser resonator and various laser processing apparatuses, drilling, marking, trimming, scribing, surface treatment, As a laser light source, it can be widely applied in other laser application fields, such as material processing, spectroscopy, wafer inspection, medical diagnosis, laser printing, and other laser irradiation processes, and it can be used for fine processing of semiconductors, display repairs, trimming systems, etc. Available for use. Thus, in this specification, the laser processing apparatus is referred to as a laser processing apparatus including those that perform such processing regardless of its name. In this specification, printing will be described as a representative example of processing. However, the present invention is not limited to printing processing, and can be used in any processing using laser light such as melting, peeling, surface oxidation, cutting, and discoloration.
(Embodiment 1)

FIG. 1 is a block diagram showing the laser processing apparatus 100 according to the first embodiment. A laser processing apparatus 100 shown in this figure includes a laser control unit 1 and a laser output unit 2. The laser control unit 1 constitutes a controller unit that controls the laser output unit 2, and is optically connected by the laser output unit 2 and the excitation light transmission medium 3. The laser output unit 2 outputs laser output light as a head unit for performing laser marking. The laser control unit 1 includes a laser excitation unit 10 that constitutes an excitation light source. In addition, an input unit 4 for inputting a machining pattern and a display unit 5 for displaying various setting screens are connected to the laser control unit 1 as necessary. On the other hand, the laser output unit 2 includes a laser resonance unit 20 that emits excitation light into a solid-state laser medium to generate laser resonance, and a laser beam scanning system for scanning the laser output light on the surface of the workpiece (workpiece) W. 30. If necessary, a work area condensing unit 40 such as an fθ lens is disposed on the output side of the laser beam scanning system 30.
(Input unit 4, display unit 5)

The input unit 4 is connected to the laser control unit 1, inputs necessary settings for operating the laser processing apparatus 100, and transmits the settings to the laser control unit 1. The setting contents are operating conditions of the laser processing apparatus 100, specific processing contents, and the like. The input unit 4 is an input device such as a keyboard, a mouse, or a console. In addition, a display unit for confirming input information input by the input unit 4 and displaying the state of the laser control unit 1 and the like can be provided separately. The display unit 5 can be a monitor such as an LCD or a cathode ray tube. If a touch panel method is used, the input unit and the display unit can also be used. Thus, the necessary setting of the laser processing apparatus 100 can be performed at the input unit without externally connecting a computer or the like.
(Laser controller 1)

  The laser control unit 1 includes a control unit 50, a memory unit 52, a laser excitation unit 10, and a power supply circuit 54. The setting content input from the input unit 4 is recorded in the memory unit 52. The control unit 50 reads the setting content from the memory unit 52 when necessary, and operates the laser excitation unit 10 based on the processing signal corresponding to the processing content to excite the solid-state laser medium 21 of the laser output unit 2. The memory unit 52 can use a semiconductor memory such as a RAM or a ROM. In addition to the built-in memory unit 52 in the laser control unit 1, a semiconductor memory card such as a detachable PC card or SD card (registered trademark), or a memory card such as a card-type hard disk can be used. The memory unit 52 composed of a memory card can be easily rewritten by an external device such as a computer, and the contents set by the computer are written in the memory card and set in the laser control unit 1 so that the input unit is laser controlled. Settings can be made without connecting to the unit. In particular, a semiconductor memory is fast in reading and writing data and has no mechanical operation part, so it is resistant to vibrations and can prevent data loss accidents due to a crash like a hard disk.

Further, the control unit 50 scans the laser beam oscillated by the solid-state laser medium 21 so as to perform the set processing on the workpiece W, and outputs a scanning signal for operating the laser beam scanning system 30 of the laser output unit 2 to the laser beam. Output to the scanning system 30. The power supply circuit 54 applies a predetermined voltage to the laser excitation unit 10 as a constant voltage power supply. The processing signal for controlling the processing operation is a PWM signal corresponding to one pulse of the laser light that is switched ON / OFF according to the HIGH / LOW and that one pulse is oscillated. Although the laser intensity of the PWM signal is determined based on a duty ratio corresponding to the frequency, the laser intensity may be changed depending on the scanning speed based on the frequency.
(Laser excitation unit 10)

  The laser excitation unit 10 includes an excitation light source 11 and an excitation light condensing unit 12 that are optically bonded. An example of the laser excitation unit 10 is shown in the perspective view of FIG. The laser excitation unit 10 shown in this figure has an excitation light source 11 and an excitation light condensing unit 12 fixed in an excitation casing 13. The excitation casing 13 is made of a metal such as copper having excellent thermal conductivity, and efficiently radiates the excitation light source 11 to the outside. The excitation light source 11 is composed of a semiconductor laser (LD), a lamp, or the like. In the example of FIG. 2, an LD array or an LD bar in which a plurality of LD elements are arranged in a straight line is used, and laser oscillation from each element is output in a line. Laser oscillation enters the incident surface of the excitation light condensing unit 12 and is output as laser excitation light collected from the exit surface. The excitation light condensing unit 12 is composed of a focusing lens or the like. The laser excitation light from the excitation light condensing unit 12 is incident on the laser resonance unit 20 through the optical fiber 14 or the like. The excitation light source 11, the excitation light condensing unit 12, and the optical fiber 14 are optically coupled through space or an optical fiber. Further, the laser excitation unit 10 can use an LD unit or an LD module in which such a member is incorporated in advance. Here, a high-power LD unit with an output of 40 W to 50 W is used, and the excitation light is branched by the branching means. Further, the excitation light emitted from the laser excitation unit 10 can be non-polarized, which is advantageous in design because it is not necessary to consider the change in the polarization state. In particular, it is preferable to provide a mechanism for making the output light non-polarized in the LD unit itself that bundles and outputs the light obtained from the LD array in which several tens of LD elements are arranged with an optical fiber. Or it is good also as a structure made into a non-polarization state (random polarization | polarized-light) in the process transmitted with the optical fiber cable from the laser excitation part 10, the process optically couple | bonded with a branch path | route by an excitation light coupling means, etc.

Further, the laser excitation unit 10 includes a temperature adjustment mechanism for adjusting the temperature of the excitation light source 11. In particular, since a semiconductor light emitting device such as an LD device has a temperature dependency in which the wavelength changes depending on the temperature, the temperature of the LD device is measured and maintained at an appropriate temperature so as to obtain laser excitation light having a desired wavelength. Control the adjustment mechanism. The temperature adjustment mechanism can use a Peltier element or the like.
(Laser output unit 2)

The laser excitation light generated in this way by the laser excitation unit 10 is transmitted to the laser output unit 2 by the excitation light transmission medium 3. An optical fiber cable or the like is used for the excitation light transmission medium 3. Further, the optical fiber 14 of the laser excitation unit 10 may be used as the excitation light transmission medium 3 as it is. The laser output unit 2 makes laser excitation light incident on the laser resonator 20 and oscillates the laser to generate laser output light, and the laser beam scanning system 30 scans the laser beam with a desired processing pattern on the work area. Let
(Laser resonator 20)

  The laser resonator 20 is a solid laser resonator or a laser oscillator unit that generates laser light by laser oscillation. The laser resonator 20 splits excitation light coupling means 22 for introducing excitation light from the excitation light source 11 and excitation light introduced from the excitation light coupling means 22 into a first branch path B1 and a second branch path B2. Along the optical path of the branching means 23, the solid laser medium 21 that is excited by the excitation light incident on the respective end faces from the first branch path B1 and the second branch path B2, and the optical path of the stimulated emission light emitted by the solid laser medium 21. The first dichroic mirror 24 and the second dichroic mirror 25 that are arranged to face each other at a predetermined distance, and an output mirror that is arranged at a position that does not interfere with the branch path and outputs reflected light from the second dichroic mirror 25 26. Here, the first dichroic mirror 24 is referred to as a rear side mirror RM, and the second dichroic mirror 25 is referred to as an emission side mirror FM. The rear side mirror RM is fixed perpendicular to the traveling direction of the laser oscillation light, while the emission side mirror FM is inclined at 45 ° with respect to the incident direction so as to reflect the laser oscillation light to the output mirror 26 side. Fixed.

  On the other hand, an aperture 27, a Q switch 28, a laser shutter, and the like are disposed between the output mirror 26 and the emission side mirror FM. An optical fiber cable that is the pumping light transmission medium 3 is connected to the pumping light coupling unit 22 so that pumping light generated by the laser pumping unit 10 is introduced into the laser resonance unit 20 and is branched by the branching unit 23 to be solid. The light is incident on each end face of the laser medium 21. The stimulated emission light emitted from the solid-state laser medium 21 is amplified by multiple reflection between the output side mirror FM and the rear side mirror RM, and is switched by the aperture 27 while being cut off in a short period by the operation of the Q switch 28. After sorting, the laser beam is output through the output mirror 26. A laser resonator is configured from the rear side mirror RM to the output mirror 26 via the emission side mirror FM.

  The aperture 27 is a shielding plate that is arranged with an aperture smaller than the aperture of the solid-state laser medium 21 aligned with the center of the optical path of the stimulated emission light, and functions as a mode selector that performs a mode selection function that suppresses unnecessary mode oscillation. . By this mode selection, the quality of laser processing is improved.

  The Q switch 28 cuts off the optical path of the stimulated emission light that travels back and forth between the output mirror 26 and the reflection mirror in a short period, and increases the number of merits (Q value) as a resonator. The operation to control ON / OFF of the. In the present embodiment, the Q switch frequency is variable from 1 kHz to 400 kHz, and CW oscillation is also possible.

  The output mirror 26 is a half mirror that outputs the reflected light from the emission side mirror FM, and is disposed at a reflection position of the second dichroic mirror 25 in a direction substantially orthogonal to the laser oscillation light at a position that does not interfere with the branch path. The

  On the other hand, the pumping light coupling means 22 is a member for optically coupling the pumping light transmission medium 3 with the branching means 23, and is split between the optical fiber coupling part 22a for connecting the optical fiber cable and the optical fiber coupling part 22a. A collimating lens 22b is provided between the means 23 and for shaping the excitation light from the LD unit incident through the optical fiber coupling portion 22a into parallel light. A plano-convex lens or the like can be used as the collimating lens 22b.

The excitation light converted into parallel light by the collimator lens 22b is transmitted to the end face side of the solid-state laser medium 21 through the first branch path B1 and the second branch path B2, and then incident on the rear side mirror RM and the output side mirror FM. Before being collected by the condenser lens. Here, the first condenser lens 61 on the first branch path B1 facing the rear-side mirror RM, and the second condenser lens 62 on the second branch path B2 facing the output-side mirror FM, respectively. Be placed. As will be described later, the first condenser lens 61 determines the spot diameter when the first excitation light R1 of the excitation light transmitted through the rear-side mirror RM is applied to the first end surface of the solid-state laser medium 21, and determines the spot diameter. The light is condensed so as to be smaller than the TEM ₀₀ mode. Further, the second condenser lens 62 determines the spot diameter when the second excitation light R2 of the excitation light transmitted through the emission side mirror FM is irradiated on the second end face of the solid-state laser medium 21, and the TEM _{00 of the} solid-state laser medium 21. Condensed so that it is smaller than the mode. The first condenser lens 61 and the second condenser lens 62 can be plano-convex lenses.
(Arrangement of laser resonator 20)

The branching unit 23 branches the excitation light output from the excitation light source 11 into the first excitation light R1 and the second excitation light R2. The branched first pumping light R1 and second pumping light R2 are respectively distributed to the first branching path B1 and the second branching path B2, and the pumping light is transmitted from the first branching path B1 to the first end surface of the solid-state laser medium 21. The first excitation light R1 is incident on the second end surface from the second branch path B2 and the second excitation light R2 is incident thereon. Such a branching unit 23 can use a beam splitter BS such as a half mirror.

The first branch path B1 and the second branch path B2 are each composed of an optical system member such as a beam splitter BS and a reflection mirror. That is, the first reflection mirror M1 that reflects the first excitation light R1 or the second excitation light R2 branched by the beam splitter BS substantially vertically and the reflected light reflected by the first reflection mirror M1 or the beam splitter BS. A second reflection mirror M2 that further reflects the branched second excitation light R2 or first excitation light R1 in a substantially vertical direction, and a third reflection that reflects the reflection light reflected by the second reflection mirror M2 substantially vertically. A branch path is formed with the mirror M3. By configuring the branch path in a rectangular shape in this way, the branch path for bi-directional excitation of the solid-state laser medium 21 can be made compact, and the arrangement and adjustment work of each reflecting mirror can be facilitated. In particular, by arranging the beam splitter BS, the first reflecting mirror M1, the second reflecting mirror M2, and the third reflecting mirror M3 on the same plane, it is possible to easily adjust the positioning of each member. In this example, all the optical members are arranged on one structural substrate 63, and a solid-state laser resonator can be designed with a simple configuration. In addition, by using only one excitation light source 11, it is possible to use one medium for transmitting the excitation light source 11 to the beam splitter BS. This also contributes to simplification of the configuration. In addition, the branching configuration with one excitation light source 11 provides an advantage that it can be configured at a lower cost than the configuration in which excitation is performed from each end face by two conventional LDs.

  The above configuration can also increase the degree of freedom in layout of each member such as the solid-state laser medium 21 and the excitation light coupling means 22. That is, the solid-state laser medium 21, the rear-side mirror RM, and the emission-side mirror FM can be arranged on any one side of the rectangular shape, and on the other hand, the rectangular shape that forms the vertex at any vertex of the rectangular shape. It can arrange | position so that the excitation light from the excitation light source 11 may inject into the extension line | wire of either side. As described above, since the arrangement of the members can be changed, there is an advantage that an appropriate layout according to the space or shape given as the laser resonator 20 can be appropriately adopted.

A specific arrangement example of the optical system members is shown in FIG. The laser resonator 201 shown in this figure has a solid-state laser medium 21, a rear-side mirror RM, and an emission-side mirror FM arranged on one long side (left side in FIG. 3) of a rectangular branch path, and the other length. A beam splitter BS1 is arranged at the apex on the side side (right side in FIG. 3) and close to the rear side mirror RM, and the excitation light coupling means 22 is placed close to the beam splitter BS1 so that the excitation light is perpendicular to the long side. It arranges so that it may enter from various directions. In other words, in FIG. 3, a vertically long rectangular rectangular beam splitter BS1 at the lower right vertex, the first reflection mirror M11 at the lower left vertex, the second reflection mirror M21 at the upper right vertex, and the third at the upper left vertex. Reflective mirrors M31 are respectively arranged. The first, second, and third reflecting mirrors M11 to M31 are fixed by being inclined in the direction of chamfering each vertex, that is, in the direction of an inner angle of 135 ° with respect to each side, so as to reflect incident light at a right angle. Has been. On the other hand, the beam splitter BS1 is fixed by being inclined in the direction of an inner angle of 45 ° with respect to each side in order to branch the incident light into transmitted light traveling straight and reflected light reflected at right angles. Excitation light coupling means 22 is arranged on the right side of the beam splitter BS1, and the excitation light from the LD unit incident through the optical fiber coupling portion 22a connected to the optical fiber cable is shaped into parallel light by the collimator lens 22b. The excitation light is incident on the beam splitter BS1 (to the left in FIG. 3). The beam splitter BS1 is fixed in an inclined posture at an angle of 45 ° with respect to the incident light, and the excitation light is obtained by using the transmitted light in the straight traveling direction as the first excitation light R1 and the reflected light reflecting upward as the second excitation light R2. Fork. A first reflecting mirror M11 is fixed to the left side of the beam splitter BS1 at an angle of 45 ° with respect to the incident light, and reflects the first excitation light R1 upward. The reflected light is condensed by the first condenser lens 61 and is input to the rear side mirror RM. As described above, the first branch path B1 is formed in an L shape.

On the other hand, the second pumping light R2 reflected upward by the beam splitter BS1 is horizontally directed (leftward in FIG. 3) by the second reflecting mirror M21 fixed in an inclined posture of 45 ° with respect to the incident light. Reflected. The reflected light travels parallel to the transmitted light of the beam splitter BS1 and is reflected downward by the third reflecting mirror M31 fixed to the incident light at an inclination of 45 °. The reflected light of the second excitation light R2 is collected by the second condenser lens 62 and is input to the exit side mirror FM. As described above, the second branch path B2 is formed in an inverted L shape. As a result, the reflected light of the first excitation light R1 reflected by the first reflection mirror M11 and the reflected light of the second excitation light R2 reflected by the third reflection mirror M31 face each other on the same axis. Then, the first excitation light R1 and the second excitation light R2 are respectively input to the rear side mirror RM and the emission side mirror FM, and are laser-oscillated by the solid laser medium 21 disposed between these dichroic mirrors, and the stimulated emission light is emitted. It is taken out from the side mirror FM. That is, the laser oscillation light is reflected in the horizontal direction (left direction in FIG. 3) by the output-side mirror FM inclined at 45 °, reaches the output mirror 26 via the Q switch 28 and the aperture 27, and then lasers. Output light is output.
(Embodiment 2)

The above layout is an example, and the arrangement of the beam splitter BS, the excitation light coupling means 22, and the solid-state laser medium 21 can be changed. Next, FIG. 4 shows an arrangement example of the optical system members of the solid-state laser oscillator according to the second embodiment as a layout example in which the position of the excitation light coupling unit 22 is changed. The laser resonator 202 shown in this figure also has a solid-state laser medium 21, a rear-side mirror RM, and an emission-side mirror FM arranged on one long side (left side in FIG. 4) of a branch path formed in a rectangular shape. The splitter BS2 is disposed at the apex on the other long side (left side in FIG. 4) on the side close to the rear side mirror RM. Here, the excitation light coupling means 22 arranged close to the beam splitter BS2 is arranged so that the excitation light enters from a direction coinciding with the long side. The arrangement of the optical members is the same as in FIG. 3. The beam splitter BS2 is at the lower right vertex of the rectangular shape that is long in the vertical direction, the first reflection mirror M12 is at the lower left vertex, the second reflection mirror M22 is at the upper right vertex, and the upper left. The third reflecting mirror M32 is arranged at the apex of each. The first, second, and third reflecting mirrors M12 to M32 are fixed by being inclined in the direction of chamfering each vertex, that is, in the direction of an inner angle of 135 ° with respect to each side so as to reflect incident light at a right angle. Has been. On the other hand, the beam splitter BS2 is fixed at an angle of 45 ° so as to equally divide the rectangular interior angle in order to branch into the transmitted light that causes the incident light to travel straight and the reflected light that is reflected at a right angle, as in FIG. ing. Excitation light is incident (upward in FIG. 4) from the excitation light coupling means 22 disposed below the beam splitter BS2. The beam splitter BS2 is fixed at an inclination different from that of FIG. 3 by 90.degree., And the excitation light is reflected with the second excitation light R2 reflecting the light transmitted in the straight direction and the first excitation light R1 reflecting the reflected light in the horizontal direction (leftward in FIG. 4). Split light. On the left side of the beam splitter BS2, as in FIG. 3, a first reflection mirror M12 is fixed with an inclination of 45 ° with respect to the incident light, and reflects the first excitation light R1 upward. The reflected light is condensed by the first condenser lens 61 and is input to the rear side mirror RM. As described above, the first branch path B1 is formed in an L shape.

On the other hand, the second excitation light R2 transmitted upward by the beam splitter BS2 is reflected in the horizontal direction (leftward in FIG. 4) by the second reflection mirror M22 fixed in an inclined posture of 45 ° with respect to the incident light. Is done. The reflected light travels in parallel with the reflected light of the beam splitter BS2, and is reflected downward by the third reflecting mirror M32 fixed at a 45 ° inclination with respect to the incident light. The reflected light of the second excitation light R2 is collected by the second condenser lens 62 and is input to the exit side mirror FM. As described above, the second branch path B2 is formed in an inverted L shape. Hereinafter, similarly to FIG. 3, the reflected light of the first excitation light R1 reflected by the first reflection mirror M12 and the reflected light of the second excitation light R2 reflected by the third reflection mirror M32 face each other on the same axis. Then, the first excitation light R1 and the second excitation light R2 are input to the rear side mirror RM and the emission side mirror FM, respectively, and are oscillated.
(Embodiment 3)

As yet another layout example, FIG. 5 shows an arrangement example of the optical system members of the solid-state laser oscillator according to the third embodiment. Also in the laser resonator 203 shown in this figure, the solid-state laser medium 21, the rear side mirror RM, and the emission side mirror FM are arranged on one long side (left side in FIG. 5) of the branch path formed in a rectangular shape. . Here, the beam splitter BS3 is arranged on the same long side and at the apex on the side close to the rear side mirror RM. Further, the excitation light coupling means 22 arranged close to the beam splitter BS3 is arranged so that the excitation light enters from a direction coinciding with the long side. Also, the optical member is arranged in a rectangular shape that is long in the vertical direction, the beam splitter BS3 at the lower left vertex, the first reflection mirror M13 at the lower right vertex, the second reflection mirror M23 at the upper right vertex, and the third reflection at the upper left vertex. Mirrors M33 are respectively arranged. Further, the first, second, and third reflecting mirrors M13 to M33 are inclined in the direction of chamfering each vertex, that is, in the direction of an inner angle of 135 ° with respect to each side so as to reflect incident light at right angles. It is fixed with. On the other hand, the beam splitter BS3 is fixed at an angle of 45 ° so as to equally divide the rectangular interior angle in order to branch into the transmitted light that makes the incident light travel straight and the reflected light that reflects at right angles, like FIG. Has been. As in FIG. 4, the excitation light is incident (upward in FIG. 5) from the excitation light coupling unit 22 disposed on the lower side of the beam splitter BS3, and the transmitted light in the straight traveling direction is converted into the first excitation light R1 and the horizontal direction ( The excitation light is branched with the reflected light reflected rightward in FIG. 5 as the second excitation light R2. The first excitation light R1, which is transmitted light, is condensed by the first condenser lens 61 and input to the rear side mirror RM. In this example, the first branch path B1 is formed linearly.

On the other hand, the second excitation light R2 reflected in the horizontal direction (rightward in FIG. 5) by the beam splitter BS3 is vertical (see FIG. 5) by the first reflection mirror M13 fixed in an inclined posture of 45 ° with respect to the incident light. (Upward at 5). The reflected light travels parallel to the transmitted light of the beam splitter BS3, and is reflected in the horizontal direction (leftward in FIG. 5) by the second reflecting mirror M23 fixed in an inclined posture of 45 ° with respect to the incident light. Further, the light is reflected in the vertical direction (downward in FIG. 5) by the third reflection mirror M33 fixed in an inclined posture of 45 ° with respect to the incident light. The reflected light of the second excitation light R2 is collected by the second condenser lens 62 and is input to the exit side mirror FM. As described above, the second branch path B2 is formed in an inverted U shape. In this way, the first excitation light R1 transmitted by the beam splitter BS3 and the reflected light of the second excitation light R2 reflected by the third reflection mirror M33 face each other on the same axis, and the first excitation light R1. The second excitation light R2 is input to the rear-side mirror RM and the emission-side mirror FM, respectively, and oscillates.
(Embodiment 4)

Furthermore, as another layout example, FIG. 6 shows an arrangement example of optical system members of the solid-state laser oscillator according to the fourth embodiment. Also in the laser resonator 204 shown in this figure, the solid-state laser medium 21, the rear side mirror RM, and the emission side mirror FM are arranged on one long side (left side in FIG. 6) of the branch path formed in a rectangular shape. . Here, the beam splitter BS4 is arranged on the same long side and at the apex on the side close to the rear side mirror RM. Further, the excitation light coupling means 22 arranged close to the beam splitter BS4 is arranged so that the excitation light enters from a direction orthogonal to the long side (left side of the apex in FIG. 6). Similarly to FIG. 5, the optical members are arranged in a vertically long rectangular shape with the beam splitter BS4 at the lower left vertex, the first reflecting mirror M14 at the lower right vertex, the second reflecting mirror M24 at the upper right vertex, and the upper left corner. A third reflecting mirror M34 is arranged at the apex. Further, the first, second, and third reflecting mirrors M14 to M34 are inclined in the direction of chamfering each vertex, that is, in the direction of an inner angle of 135 ° with respect to each side so as to reflect incident light at a right angle. It is fixed with. On the other hand, the beam splitter BS4 is fixed at an angle of 45 ° so as to equally divide the interior angle of the rectangle in order to divide into the transmitted light that causes the incident light to travel straight and the reflected light that is reflected at a right angle as in FIG. Has been. As in FIG. 5, the excitation light is incident in the right direction in FIG. 6 from the excitation light coupling means 22 disposed on the left side of the beam splitter BS4, and the transmitted light in the straight traveling direction is converted into the second excitation light R2 in the vertical direction (in FIG. 6). The reflected light reflected upward) is used as the second excitation light R2, and the excitation light is branched. The first excitation light R1, which is reflected light, is collected by the first condenser lens 61 and is input to the rear side mirror RM. Also in this example, the first branch path B1 is formed in a straight line.

On the other hand, the second pumping light R2 that passes through the beam splitter BS4 and goes straight to the right in FIG. 6 is perpendicular to the first reflecting mirror M14 that is fixed at an inclination of 45 ° with respect to the incident light as in FIG. Reflected in the direction (upward in FIG. 6). The reflected light travels parallel to the reflected light of the beam splitter BS4, and is reflected in the horizontal direction (leftward in FIG. 6) by the second reflecting mirror M24 fixed in an inclined posture of 45 ° with respect to the incident light. Further, the light is reflected in the vertical direction (downward in FIG. 6) by the third reflecting mirror M34 fixed in an inclined posture of 45 ° with respect to the incident light. The reflected light of the second excitation light R2 is collected by the second condenser lens 62 and is input to the exit side mirror FM. As described above, the second branch path B2 is formed in an inverted U shape. In this way, the first excitation light R1 reflected by the beam splitter BS4 and the reflection light of the second excitation light R2 reflected by the third reflection mirror M34 face each other on the same axis, and the first excitation light R1. The second excitation light R2 is input to the rear-side mirror RM and the emission-side mirror FM, respectively, and oscillates.
(Embodiment 5)

Furthermore, as another layout example, FIG. 7 shows an arrangement example of optical system members of the solid-state laser oscillator according to the fifth embodiment. The laser resonator 205 shown in this figure also has a solid-state laser medium 21, a rear-side mirror RM, and an emission-side mirror FM arranged on one long side (left side in FIG. 7) of a rectangular branch path. . Here, the beam splitter BS5 is arranged on the same long side and at the apex on the side close to the emission side mirror FM. Further, the excitation light coupling means 22 arranged close to the beam splitter BS5 is arranged so that the excitation light enters from a direction orthogonal to the long side (left side of the apex in FIG. 7). Further, the optical member is arranged in a rectangular shape that is long in the vertical direction, the beam splitter BS5 at the top left vertex, the first reflection mirror M15 at the top right vertex, the second reflection mirror M25 at the bottom right vertex, and the third reflection at the bottom left vertex. Mirrors M35 are respectively arranged. Further, the first, second, and third reflecting mirrors M15 to M35 are inclined in the direction of chamfering each vertex, that is, in the direction of an inner angle of 135 ° with respect to each side so as to reflect incident light at right angles. It is fixed with. On the other hand, the beam splitter BS5 is fixed at an angle of 45 ° so as to equally divide the rectangular interior angle in order to branch into the transmitted light that makes the incident light travel straight and the reflected light that reflects at right angles, as in FIG. Has been. Here, the excitation light is incident in the right direction in FIG. 7 from the excitation light coupling means 22 disposed on the left side of the beam splitter BS5, and the transmitted light in the straight traveling direction is the first excitation light R1 in the vertical direction (downward in FIG. 7). The reflected light to be reflected is used as the second excitation light R2, and the excitation light is branched. The second excitation light R2, which is reflected light, is collected by the second condenser lens 62 and is input to the exit side mirror FM. In this example, the second branch path B2 is formed in a straight line.

On the other hand, the first pumping light R1 that passes through the beam splitter BS5 and goes straight to the right in FIG. 7 is a first reflecting mirror M15 that is fixed in an inclined posture of 45 ° with respect to the incident light, and is in the vertical direction (in FIG. 7). Reflected downward). The reflected light travels in parallel with the reflected light of the beam splitter BS5, and is reflected in the horizontal direction (leftward in FIG. 7) by the second reflecting mirror M25 fixed in an inclined posture of 45 ° with respect to the incident light. Further, the light is reflected in the vertical direction (upward in FIG. 7) by the third reflecting mirror M35 fixed at a 45 ° inclination with respect to the incident light. The reflected light of the first excitation light R1 is collected by the first condenser lens 61 and is input to the rear side mirror RM. As described above, the first branch path B1 is formed in a U shape. In this way, the second excitation light R2 reflected by the beam splitter BS5 and the reflection light of the first excitation light R1 reflected by the third reflection mirror M35 face each other on the same axis, and the first excitation light R1. The second excitation light R2 is input to the rear-side mirror RM and the emission-side mirror FM, respectively, and oscillates.
(Embodiment 6)

Furthermore, as another layout example, FIG. 8 shows an arrangement example of the optical system members of the solid-state laser oscillator according to the sixth embodiment. Also in the laser resonator 206 shown in this figure, the solid-state laser medium 21, the rear-side mirror RM, and the emission-side mirror FM are arranged on one long side (left side in FIG. 8) of the branch path formed in a rectangular shape. . Here, the beam splitter BS6 is arranged on the same long side and at the apex on the side close to the emission side mirror FM. Further, the excitation light coupling means 22 arranged close to the beam splitter BS6 is arranged so that the excitation light enters from the direction (upper side of the apex in FIG. 8) coincident with the long side. Similarly to FIG. 7, the arrangement of the optical members is a beam splitter BS6 at the upper left vertex of the rectangular shape that is long in the vertical direction, the first reflection mirror M16 at the upper right vertex, the second reflection mirror M26 at the lower right vertex, and the lower left corner. A third reflecting mirror M36 is arranged at the apex. Further, the first, second, and third reflecting mirrors M16 to M36 are inclined in the direction of chamfering each vertex, that is, in the direction of an inner angle of 135 ° with respect to each side so as to reflect incident light at right angles. It is fixed with. On the other hand, the beam splitter BS6 is fixed at an angle of 45 ° so as to equally divide the rectangular interior angle in order to branch into the transmitted light that makes the incident light travel straight and the reflected light that reflects at right angles, as in FIG. Has been. Here, the excitation light is incident downward in FIG. 8 from the excitation light coupling means 22 disposed on the upper side of the beam splitter BS6, and the transmitted light in the straight traveling direction is directed to the second excitation light R2 in the horizontal direction (rightward in FIG. 8). The reflected light to be reflected is the first excitation light R1, and the excitation light is branched. The second excitation light R2, which is transmitted light, is condensed by the second condenser lens 62 and is input to the exit side mirror FM. Also in this example, the second branch path B2 is formed in a straight line.

On the other hand, the first pumping light R1 reflected by the beam splitter BS6 and traveling straight to the right in FIG. 8 is perpendicular to the first reflecting mirror M16 fixed at a 45 ° inclination with respect to the incident light as in FIG. Reflected in the direction (downward in FIG. 8). The reflected light travels parallel to the transmitted light of the beam splitter BS6, and is reflected in the horizontal direction (leftward in FIG. 8) by the second reflecting mirror M26 fixed at a 45 ° inclination with respect to the incident light. Further, the light is reflected in the vertical direction (upward in FIG. 8) by the third reflecting mirror M36 fixed at an inclination of 45 ° with respect to the incident light. The reflected light of the first excitation light R1 is collected by the first condenser lens 61 and is input to the rear side mirror RM. As described above, the first branch path B1 is formed in a U shape. In this way, the second excitation light R2 transmitted by the beam splitter BS6 and the reflected light of the first excitation light R1 reflected by the third reflection mirror M36 face each other on the same axis, and the first excitation light R1. The second excitation light R2 is input to the rear-side mirror RM and the emission-side mirror FM, respectively, and oscillates.
(Embodiment 7)

Furthermore, as another layout example, FIG. 9 shows an arrangement example of optical system members of the solid-state laser oscillator according to the seventh embodiment. Also in the laser resonator 207 shown in this figure, the solid-state laser medium 21, the rear side mirror RM, and the emission side mirror FM are arranged on one long side (left side in FIG. 9) of the branch path formed in a rectangular shape. . Here, the beam splitter BS7 is arranged at the apex on the other long side (right side in FIG. 9) on the side close to the emission side mirror FM. Further, the excitation light coupling means 22 arranged close to the beam splitter BS7 is arranged so that the excitation light enters from a direction (upper side of the apex in FIG. 9) coincident with the long side. Further, the optical member is arranged in a vertically long rectangular shape with a beam splitter BS7 at the upper right vertex, a first reflecting mirror M17 at the lower right vertex, a second reflecting mirror M27 at the lower left vertex, and a third reflection at the upper left vertex. Mirrors M37 are respectively arranged. Further, the first, second, and third reflecting mirrors M17 to M37 are inclined in the direction of chamfering each vertex, that is, in the direction of an inner angle of 135 ° with respect to each side so as to reflect incident light at a right angle. It is fixed with. On the other hand, the beam splitter BS7 is fixed at an angle of 45 ° so as to equally divide the rectangular interior angle in order to branch into the transmitted light that makes the incident light travel straight and the reflected light that reflects at right angles, as in FIG. Has been. Here, the excitation light is incident downward in FIG. 9 from the excitation light coupling means 22 disposed on the upper side of the beam splitter BS7, and the transmitted light in the straight traveling direction is the first excitation light R1 in the horizontal direction (leftward in FIG. 9). The reflected light to be reflected is used as the second excitation light R2, and the excitation light is branched. On the left side of the beam splitter BS7, a third reflection mirror M37 is fixed with an inclination of 45 ° with respect to the incident light, and reflects the second excitation light R2 downward. This reflected light is condensed by the second condenser lens 62 and is input to the exit side mirror FM. As described above, the second branch path B2 is formed in an inverted L shape.

On the other hand, the first excitation light R1 transmitted through the beam splitter BS7 and traveling straight downward in FIG. 9 is a horizontal direction (in FIG. 9) by the first reflection mirror M17 fixed at a 45 ° inclination with respect to the incident light. Reflected left). The reflected light travels parallel to the reflected light of the beam splitter BS7, and is reflected in the vertical direction (upward in FIG. 9) by the second reflecting mirror M27 fixed in an inclined posture of 45 ° with respect to the incident light. The reflected light of the first excitation light R1 is collected by the first condenser lens 61 and is input to the rear side mirror RM. As described above, the first branch path B1 is formed in a U shape. In this way, the second excitation light R2 reflected by the third reflection mirror M37, and the reflected light of the first pumping light R1 reflected by the second reflecting mirror M27 is opposite in the same axis, the first excitation The light R1 and the second excitation light R2 are input to the rear side mirror RM and the emission side mirror FM, respectively, and are oscillated.
(Embodiment 8)

Furthermore, as another layout example, FIG. 10 shows an arrangement example of the optical system members of the solid-state laser oscillator according to the eighth embodiment. Also in the laser resonator 208 shown in this figure, the solid-state laser medium 21, the rear-side mirror RM, and the emission-side mirror FM are arranged on one long side (left side in FIG. 10) of the branch path formed in a rectangular shape. . Here, the beam splitter BS8 is arranged at the apex on the other long side (right side in FIG. 10) on the side close to the exit side mirror FM. Further, the excitation light coupling means 22 arranged close to the beam splitter BS8 is arranged so that the excitation light is incident from a direction orthogonal to the long side (right side of the apex in FIG. 10). Similarly to FIG. 9, the optical members are arranged in a vertically long rectangular shape with a beam splitter BS8 at the upper right vertex, a first reflecting mirror M18 at the lower right vertex, a second reflecting mirror M28 at the lower left vertex, and an upper left corner. A third reflecting mirror M38 is arranged at the apex. Further, the first, second, and third reflecting mirrors M18 to M38 are inclined in the direction of chamfering each vertex, that is, in the direction of an inner angle of 135 ° with respect to each side so as to reflect incident light at right angles. It is fixed with. On the other hand, the beam splitter BS8 is fixed at an angle of 45 ° so as to equally divide the rectangular interior angle in order to branch into the transmitted light that makes the incident light travel straight and the reflected light that reflects at right angles, like FIG. Has been. Here, the excitation light is incident in the left direction in FIG. 10 from the excitation light coupling means 22 arranged on the right side of the beam splitter BS8, and the transmitted light in the straight traveling direction is the second excitation light R2 in the vertical direction (downward in FIG. 10). The reflected light to be reflected is the first excitation light R1, and the excitation light is branched. On the left side of the beam splitter BS8, a third reflecting mirror M38 is fixed at an angle of 45 ° with respect to the incident light, and the transmitted second excitation light R2 is reflected downward. This reflected light is condensed by the second condenser lens 62 and is input to the exit side mirror FM. As described above, the second branch path B2 is formed in an inverted L shape.

On the other hand, the first excitation light R1 that is reflected by the beam splitter BS8 and travels downward in FIG. 10 is a first reflection mirror M18 that is fixed in an inclined posture of 45 ° with respect to the incident light, and in the horizontal direction (in FIG. Reflected left). The reflected light travels in parallel with the transmitted light of the beam splitter BS8, and is reflected in the vertical direction (upward in FIG. 10) by the second reflecting mirror M28 fixed in an inclined posture of 45 ° with respect to the incident light. The reflected light of the first excitation light R1 is collected by the first condenser lens 61 and is input to the rear side mirror RM. As described above, the first branch path B1 is formed in a U shape. In this way, the second excitation light R2 reflected by the third reflection mirror M38, and the reflected light of the first pumping light R1 reflected by the second reflecting mirror M28 is opposite in the same axis, the first excitation The light R1 and the second excitation light R2 are input to the rear side mirror RM and the emission side mirror FM, respectively, and are oscillated.

  As described above, the arrangement of the excitation light source 11 for injecting the excitation light into the solid-state laser medium 21 can be simplified by configuring the excitation light branch path in a rectangular shape. A modified example of such an arrangement pattern is collectively shown in the schematic diagram of FIG. In this figure, the numbers in parentheses correspond to the numbers in the embodiment. In this way, the branch path B, which is a combination of the first branch path and the second branch path, is formed in a rectangular shape, the solid-state laser medium 21 is arranged on the axis of one side (here, the long side) of the rectangle, It can arrange | position so that excitation light may inject along any side in any rectangular corner. For this reason, the arrangement position of the excitation light source 11 can be easily changed while maintaining the branch path B in a rectangular shape. As described above, the layout can be easily changed, and bi-directional excitation can be realized with a very simple and compact configuration.

  As shown in FIG. 11, it is desirable that the solid-state laser medium 21 be disposed on any long side of a rectangular shape. The sides on which the solid-state laser medium 21 is arranged need a certain length because the rear-side mirror RM, the emission-side mirror FM, and the like are arranged in addition to the solid-state laser medium 21, and these are arranged on the short side. This is because there is no need to make this portion short, so that the rectangular shape of the branch path can be made compact, and the laser resonator can be miniaturized. However, depending on the layout of the laser resonator, it can be arranged on the short side as shown in FIG. Further, the branch path is not limited to a rectangular shape, and may be formed in a square shape as shown in FIG. Thereby, since the solid-state laser medium 21 can be disposed on any side, the degree of freedom in layout is further increased. That is, the arrangement of the optical members can be appropriately distributed according to physical space and layout requirements, and an efficient arrangement can be adopted.

As will be described later, from the viewpoint of adding a lot of excitation light branching components to the rear surface side of the solid-state laser medium 21, the third embodiment, the fourth embodiment, or the first embodiment in which the number of reflections by the reflection mirror is small and the loss is small. 2 is preferable. In particular, the third embodiment is preferable from the viewpoint of reducing loss because the first branch component input to the rear surface side can be input to the first end surface without being reflected. However, it goes without saying that the same effect can be obtained in other embodiments by adjusting the branching ratio by the beam splitter. The adjustment on the beam splitter side can be designed in consideration of the loss due to the reflection mirror, and a free arrangement is possible without being restricted by the layout.
(Solid laser medium 21)

The solid-state laser medium 21 is a crystal that extends in one direction and has two end faces in the longitudinal direction. Here, the end face is composed of a first end face constituting the excitation light incident face and a second end face opposite to the first end face and constituting the excitation light incidence face and the excitation light extraction face. . In the example of FIG. 3, the second end face is referred to as a take-out face (outgoing face), and the first end face is referred to as a rear face (incident face). The exit surface is opposed to the exit side mirror FM, and the rear surface is opposed to the rear side mirror RM. Further, out of the excitation light branched into the first excitation light R1 and the second excitation light R2 by the beam splitter BS, the first excitation light R1 is incident on the rear surface side, and the second excitation light R2 is incident on the emission surface side. The

In the above example, a rod-shaped Nd: YVO ₄ crystal is used as the solid-state laser medium 21. The wavelength of the semiconductor laser for excitation of the solid-state laser medium 21 was set in the vicinity of 808 nm which is the central wavelength of the absorption spectrum of Nd: YVO ₄ . However, the present invention is not limited to this example, and other solid-state laser medium 21 such as YAG doped with rare earth, LiSrF, LiCaF, YLF, NAB, KNP, LNP, NYAB, NPP, GGG or the like can also be used. Further, the wavelength of the laser beam to be output can be converted to an arbitrary wavelength by combining the solid-state laser medium 21 with a wavelength conversion element. Examples of the wavelength conversion element include KTP (KTiPO ₄ ), organic nonlinear optical materials and other inorganic nonlinear optical materials such as KN (KNbO ₃ ), KAP (KAsPO ₄ ), BBO, LBO, and bulk polarization inversion elements ( LiNbO ₃ (Periodically Polled Lithium Niobate: PPLN), LiTaO ₃ or the like) can be used. Further, a semiconductor laser for an excitation light source of a laser by up-conversion using a fluoride fiber doped with rare earth such as Ho, Er, Tm, Sm, and Nd can be used. Thus, in this embodiment, various types can be appropriately used as a laser generation source.
(Nd concentration)

The rod-shaped solid laser medium 21 crystal can be used in either a cylindrical shape or a prismatic shape. Here, an Nd: YVO ₄ crystal having a rectangular parallelepiped shape with an end face of 3 mm (H) × 3 mm (W) and a length (L) of 15 mm was used as the prismatic solid laser medium 21 crystal. Further, the Nd concentration is preferably 1% or less.

In general, the higher the Nd concentration, the better the absorption of laser light. On the other hand, if the concentration is too high, the excitation light does not penetrate to the deep part of the crystal and tends to be excited in a narrow surface area. In particular, since the Nd: YVO ₄ crystal has a small thermal conductivity coefficient, if the LD unit has a high output, a thermal lens may be generated and damaged. YVO ₄ crystal is a uniaxial crystal and has a strong cleavage, so that it has a property of being easily broken along the C axis. As described above, the use of a high concentration crystal makes it easy to generate an overheated lens, which causes the operation of the resonator to become unstable, leading to a decrease in beam quality. There was also a risk of causing it. In particular, the YVO ₄ crystal is a uniaxial crystal and has a strong cleavage property, and therefore has a property of being easily broken along the C axis. In order to alleviate this, it is effective to lower the Nd concentration.

  However, if the Nd concentration is lowered, the total amount of absorption into the crystal increases, but the spatial matching between the laser beam mode and the absorption section decreases, so that the excitation light cannot be used effectively and the absorption efficiency decreases. To do. In addition, when a low concentration crystal is used, there is a problem that it becomes sensitive to the wavelength of the LD that is the excitation light source 11 and a stable wavelength cannot be obtained. Therefore, it is necessary to appropriately adjust the Nd concentration in consideration of these.

FIG. 14 is a graph showing a change in absorption efficiency with respect to the wavelength of excitation light in an Nd: YVO ₄ crystal. Here, the ratio of the absorbed light to the total excitation light was compared for a plurality of crystals having Nd: YVO ₄ crystals with end faces of 3 mm × 3 mm and varying the crystal length and Nd concentration. Specifically, the Nd concentration when the crystal length is 15 mm is changed to 0.10%, 0.20%, 0.27%, 0.30%, 0.40%, and the Nd concentration is 0.27%. In this case, the measurement was performed for each of the examples in which the crystal length was changed to 10 mm. As shown in this figure, the higher the Nd concentration, the higher the laser beam absorption efficiency. In both cases, the absorption efficiency peaked when the wavelength of the excitation light was around 808 nm to 809 nm. However, if the Nd concentration is increased too much, instability or damage due to heat occurs. For this reason, the Nd concentration of the solid-state laser medium 21 is set to 1% or less, preferably 0.1% to 0.4%. However, the Nd concentration of the actually produced solid-state laser medium 21 crystal has a variation of about ± 0.03% to 0.05%, and considering these, about 0.22% to 0.32%. Set to Most preferably, the absorption efficiency can be maintained in a well-balanced manner by setting it to around 0.27%. Further, since the absorption efficiency tends to decrease when the crystal length (L) is shortened, the crystal is set to about 10 mm to 20 mm, preferably 13 mm to 17 mm, more preferably about 15 mm.

  Note that the cross section of the crystal of the solid-state laser medium 21 need only be larger than the spot diameter of the excitation light, and the crystal shape is not limited to a rectangular parallelepiped shape, and a cylindrical shape or other shapes can be used as appropriate. For example, if the spot diameter of the excitation light is φ1 mm, it may be a cylindrical shape having this size. However, if the solid laser medium 21 crystal is thin, there is a problem that it is easy to break. Considering the ease of handling of the crystal during assembly, the area of the crystal end face and the shape of the crystal should be constant. In this case, the crystal end face is a rectangular parallelepiped shape of 3 mm × 3 mm.

If necessary, the thermal lens effect can be suppressed by applying gold plating or the like to the side surface of the Nd: YVO ₄ crystal, and the oscillation mode of the solid-state laser medium 21 can be enhanced.
(Bidirectional excitation method)

In the laser processing apparatus that excites the solid-state laser medium 21, 30% to 40% of the excitation power is lost due to heat due to the limit of quantum efficiency. Therefore, in order to exhibit the extreme performance, it is necessary to solve various thermal problems such as thermal birefringence, thermal lens, thermal doublet lens, and destruction due to heat, which are manifested by strong excitation. In particular, in an LD-pumped solid-state laser processing apparatus, heat generated by the absorption of pumping light of the solid-state laser medium 21 induces a lens effect on the crystal itself, thereby generating a thermal lens. The thermal lens significantly impedes the stability of the laser resonator and becomes a major obstacle to the resonator design. In order to deal with such a problem, the present embodiment adopts a two-way excitation method, uses one excitation light source 11 as the laser excitation unit 10, and branches it from each end face. And succeeded in suppressing the generation of thermal lenses. In addition to this, an effect of improving the stability with respect to the excitation wavelength and the rise characteristic can be obtained.
(Stability against wavelength change)

FIG. 15 shows a graph comparing the change in laser output light with respect to the wavelength of the LD unit by unidirectional excitation and bidirectional excitation. Here, a rectangular parallelepiped shape having an end face of 3 mm × 3 mm is used as the Nd: YVO ₄ crystal, the Nd concentration is 0.27% as the unidirectional excitation, the crystal length is 10 mm, and the Nd concentration is 0.27% as the bidirectional excitation. A crystal length of 15 mm was used. As shown in this figure, in the unidirectional excitation, when the wavelength of the excitation light is shifted around 808 nm, the laser output light also changes greatly. For this reason, the laser output changes due to variations in the peak wavelength of the LD unit, making it difficult to obtain a homogeneous laser processing apparatus. In particular, semiconductor light-emitting elements generally have individual differences and tend to cause wavelength variations, so it is usually necessary to consider an error of about ± 2 nm to 3 nm. Furthermore, since the wavelength of the excitation light has temperature dependence, it is necessary to control the temperature of the LD element using a Peltier element or the like. For this reason, in the past, design was made in accordance with the lowest laser output in consideration of wavelength variation, and the original output was not utilized.

On the other hand, in the two-way excitation, the laser output light is stable even if the excitation light deviates from 808 nm. From this, it was confirmed that the wavelength dependence of the excitation light was suppressed by two-way excitation, and a stable laser output light could be obtained regardless of the wavelength change of the LD unit.
(Rise characteristics)

Further, FIG. 16 shows a graph comparing the temporal change of the laser output light between the one-directional excitation and the two-directional excitation. Also in this figure, a rectangular parallelepiped Nd: YVO ₄ crystal having an Nd concentration of 0.27% and an end face of 3 mm × 3 mm is used, and the wavelength of the LD unit is changed to 806 nm, 808 nm, and 810 nm, and one-directional excitation and two-directional excitation are performed. The time change of the laser output light when the current of each LD unit was changed from 0 A to 35 A was measured. The crystal length was set to 10 mm (unidirectional excitation) and 15 mm (bidirectional excitation) for convenience of the comparative test. As shown in this figure, in the unidirectional excitation, when the excitation wavelength is 808 nm or 810 nm, a moderate increase is observed. On the other hand, overshoot occurs at 806 nm, and about 1.4 until the output is stabilized. It takes seconds. On the other hand, in the bi-directional excitation, a steep rise and early stability were exhibited at any wavelength, and it was confirmed that the laser rise characteristics were excellent. Moreover, the overshoot at 806 nm is also suppressed to an extremely low level.

To confirm this, FIG. 17 shows that the LD unit current is changed from 0 A to 45 A in the bi-directional excitation using a rectangular Nd: YVO ₄ crystal having a Nd concentration of 0.27% and 3 mm × 3 mm × 15 mm as in FIG. The waveform which measured the time change of the laser output light at the time of making it with the photodiode is shown. As is apparent from this figure, it was confirmed that the desired laser output light level was reached in an extremely short time of about 20 ms and a stable output was obtained without causing overshoot. As described above, according to the conditions of the present embodiment, the time required for the output to stabilize at the rise of the laser output light can be increased to 1/10 or less of the conventional time. As a result, it is possible to realize high-speed machining with improved responsiveness and follow-up while maintaining machining accuracy and reduced standby time. In conventional laser processing, due to the problem of responsiveness of laser output, the laser output cannot be changed for each block of the laser processing pattern, and when changing the laser output, it waits until the output stabilizes. Time (eg 300 ms) was required. On the other hand, since the above configuration is excellent in stability at the time of start-up, high-speed tracking is possible, and the laser output can be changed for each block of the laser processing pattern, which has been difficult in the past.

In this way, by adopting the above configuration, it is possible to suppress the change in the laser output with respect to the wavelength of the LD unit, and further, the excellent advantage that the followability of the output laser light is fast with respect to the change in the laser output value. Is realized. According to the test conducted by the present inventor, in the conventional example, when the setting of the laser output light is changed from 0% to 100%, the followability of the actually output laser output light is 300 msec. On the other hand, 20 msec was achieved in this embodiment.
(Adjustment of branching ratio by branching means 23)

  The laser excitation light branched in two directions from the single excitation light source 11 is pumped from each end face in the longitudinal direction of the solid-state laser medium 21. At this time, the magnitude of the excitation light input from the rear side mirror RM side is made larger than the excitation light input from the output side mirror FM side. As a result of diligent research on the thermal lens, the present inventor has found that the thermal lens generated on the rear side of the solid-state laser medium has less influence on the inside of the resonator than the emission side. In the configuration of FIG. 3, the branching ratio to the rear side mirror RM and the output side mirror FM is adjusted by the reflectance of the beam splitter BS. That is, as the reflectivity is higher, more excitation light is irradiated on the emission surface side. Conversely, as the reflectivity is lower, that is, as the transmittance is higher, more excitation light is irradiated on the rear surface side. Here, it is preferable that the branching ratio at the beam splitter BS is such that 50% or more of the total power is input to the crystal end face on the rear face side.

Further, in order to further optimize the reflectivity, the reflectivity of the beam splitter is changed in the two-way excitation method, and the result of measuring the power of the laser output light with respect to the power of the LD of the excitation light source is shown in FIGS. 19 shows. In these figures, typical output characteristics when the reflectivity of the beam splitter is 20%, 33%, and 45% are measured. FIG. 18 shows the output during CW operation, and FIG. 19 shows the output during Q switch operation. Each is shown. As is clear from these figures, the laser output increases as the LD power of the excitation light source increases, but the saturation of the output, which is a feature of the thermal lens, from around 45 W during CW operation and from around 40 W during Q switch operation. A decrease is seen. In this state, it was observed that the beam mode was also deteriorated. From this, it was confirmed that the decrease in the laser output becomes remarkable even when the reflectance is too low. In practical use, the reflectance is preferably in the range of 30% to 50%. Most preferably, the reflectance is set to around 33%, that is, the ratio at which the beam splitter splits the incident light into the rear surface and the output surface is set to approximately 2: 1. In the vicinity of this value, the highest laser output was obtained, and it was confirmed that high-efficiency operation with minimal reduction in laser output was obtained. The superiority of the above numerical range was confirmed both in CW operation and in Q switch operation. In addition, it is confirmed that the Q switch operation is more susceptible to the influence of the thermal lens because the laser output as a whole is lower than in the CW operation, and the excitation light is reduced from a low stage. It was.

If the ratio of branching to the rear side is increased too much, there is a high possibility that the excitation light is unevenly distributed on the rear side and a thermal lens is generated on this surface. Therefore, the ratio of branching incident light to the rear surface and the exit surface is 4. : 1 vicinity is the upper limit.
(Output mirror reflectivity)

  On the other hand, the energy that can be extracted from the resonator is determined by the reflectance of the output mirror. For this reason, it is necessary to optimally set the reflectance. In general, when the reflectance of the resonator is increased, the energy confined inside the resonator is increased, so that there is a high possibility that the optical member constituting the inside of the resonator is damaged. For this reason, from the viewpoint of reducing the load on the optical member, it is desirable to design the reflectance of the output mirror to a low value. For this purpose, it is necessary to increase the excitation density inside the crystal. In excitation, there is a limit to increasing the excitation density from the viewpoint of thermal lens and crystal damage.

Here, FIG. 20 shows an equation for calculating the energy inside the resonator. As shown in this figure, the energy E _rsn confined inside the resonator is represented by E _rsn = {(1 + R) X} / (1 where X is the output emitted from the output mirror and R is the reflectance of the output mirror. -R). To design a laser processing apparatus that obtains 10 W of laser output light, if the output mirror has a reflectivity of 90%, energy of 190 W is accumulated inside the resonator. Such high energy causes heat to be generated in the optical member constituting the resonator, and in some cases, the quality of the laser beam is deteriorated due to optical thermal distortion generated in a mirror or the like. In particular, in a pulse laser equipped with a Q switch, a peak power of several tens of kW is generated, thereby damaging an optical member constituting the resonator.

Therefore, by reducing the reflectivity of the output mirror from 90% to 70%, the energy accumulated in the resonator can be suppressed to about one third. If it is further reduced to 50%, it can be reduced to about a half. Thus, it is desirable to design the output mirror to have a low reflectance. Preferably, the reflectance can be made 70% or less, and the power can be taken out efficiently. Also, from the viewpoint of stability, setting the reflectance to about 50% can provide the advantage of improving reliability, although the output is somewhat reduced.
(Output mirror reflectance lower limit setting)

  On the other hand, if the reflectivity of the output mirror is too low, there is a possibility that harmful effects may occur. FIG. 21 shows a change in laser output with respect to the reflectivity of the output mirror in the two-way excitation method, and FIG. 22 shows a change in resonator internal energy with respect to the reflectivity of the output mirror.

  It can be seen from FIG. 21 that the output mirror gives the maximum output when the reflectance is about 70 to 80%. Further, even at 50 to 60%, an output of nearly 90% of the above range can be maintained, and the energy confined inside the resonator from FIG. 22 can be kept low. For this reason, from the viewpoint of reducing the resonator internal energy, it is preferable to set the reflectance of the output mirror to 50 to 60%.

  On the other hand, even if the output mirror reflectivity is set to a lower value of 30 to 50%, the output is expected to be 80% or more according to FIG. 21, and the energy confined inside the resonator can be further reduced from FIG. From the viewpoint of ensuring reliability even if the output is somewhat sacrificed, it seems to be a preferable configuration at first glance. However, when the reflectance is set to 30% or less, the energy confined inside the resonator cannot be reduced by the amount that the output is reduced.

In particular, when such a low reflectance is selected, even if a certain level of output can be secured at the maximum excitation power, when the excitation power is changed stepwise or when the output is changed at a low output It becomes a problem. In general, the design of the output mirror reflectivity is determined based on this data on the assumption that the maximum excitation power is equal to the maximum output generation time. However, an actual laser processing apparatus is not always used at the maximum output, and is also used in a different excitation range below this. In such a case, when the output mirror reflectivity is extremely low, there is a problem that the laser oscillation threshold is increased. FIG. 23 shows a graph in which the power of the laser output light is measured with respect to the power of the LD of the excitation light source when the reflectivity of the beam splitter is increased (50%) and decreased (3%) compared to FIG. As shown in this figure, the laser oscillation threshold value of the excitation light from which the laser output light can be obtained increases from about 13 W to 20 W when the reflectance decreases. This is because the gain inside the solid-state laser medium decreases when the power of the LD unit is low, that is, the pumping density decreases. As a result, the optimum output mirror reflectivity is relative to the case where the power of the LD unit is high. This is because it becomes larger. For this reason, when the power of the LD unit is low, the optimum reflectance is not designed, and inefficient oscillation is forced. In the case of such oscillation efficiency, the output becomes unstable, and there arises a problem that the change in laser output light due to temperature and mirror coating deterioration with time increases. For this reason, if the output mirror reflectivity is excessively lowered, the overall merit cannot be obtained. Considering this point, it can be said that the reflectance of the output mirror is preferably in the range of 30% to 70%. More preferably, it is 40% to 50%.
(Advantage of reducing output mirror reflectivity)

Here, the calculation formula of the laser output P is examined. The transmittance of the output mirror is T, the internal loss of the resonator is Loss, the cross-sectional area of the solid-state laser medium (effective pumping cross-sectional area) is A, the crystal length of the solid-state laser medium (effective pumping length) is L, and the solid-state laser The small signal gain generated in the medium is g ₀ , and the saturation constant is Is (= hν / δτ _f ). At this time, the laser output P is expressed by the following equation (1).
[Equation 1]
P = T · (T + Loss) · A · Is · g ₀ · L−T · A · Is / 2

Considering the above equation 1 as an equation of T, the power that can be extracted from the output mirror becomes maximum when T _opt gives a maximum value. Therefore, when T _opt is calculated, the following equation (2) is obtained.
[Equation 2]
T _opt = ((sqrt (2 · g ₀ · L / Loss) −1) Loss

From Equation 2, the larger the small signal gain g ₀ , the larger the optimum output mirror transmittance T _opt becomes, and hence the output mirror reflectivity R becomes smaller. From the above, if the design is such that the small signal gain g ₀ is increased, the reflectance R of the output mirror that can extract energy most efficiently can be reduced. On the other hand, if the reflectance R of the output mirror and the output that can be extracted from the output mirror are X, the power confined inside the resonator can be expressed by the following equation (3) as shown in FIG.
[Equation 3]
(1 + R) · X / (1-R)

  From this, it can be seen that the smaller the reflectivity R of the output mirror, the smaller the energy confined inside the resonator, and the lower the risk of coating damage on the output mirror, rear side mirror, and solid laser medium end face.

On the other hand, the small signal gain g ₀ is expressed by the following equation (4).
g ₀ = σ · N ₀ · Wp · τ _f

In the above equation, σ is a stimulated emission cross-sectional area, and τ _f is a fluorescence lifetime, both of which are physical property values, which are determined by the type of solid-state laser medium (Nd: YVO ₄ or Nd: YLF, etc.). On the other hand, N ₀ and Wp mean the pumping rate of the excitation source (number of atoms) existing in the unit volume, and the product N ₀ · Wp means the number of excited atoms per unit time and unit volume. become. Therefore, in order to design a laser processing apparatus with a large g ₀ , it is only necessary to increase the number of atoms excited in a unit volume by concentrating excitation light on a small volume and increasing the excitation density. g ₀ leads to the fact that large. As a result, if the excitation volume is designed to be small and the excitation density is increased and excitation is performed, g ₀ increases, and as a result, even if the output mirror reflectance is lowered, the laser can be extracted more efficiently than the output mirror. You can do it. As a result, the risk of damage to the coating used in the optical member constituting the resonator can be reduced.

From the above viewpoint, a design that increases the excitation density is preferable. However, because of the thermal lens generated inside the solid-state laser medium, the output according to the above calculation formula cannot actually be obtained. The thermal lens generated inside the solid-state laser medium may deteriorate the mode, and in some cases, the stable operation of the resonator may be hindered and the laser may not oscillate. Therefore, it can be said that it is preferable to increase the excitation density based on the above theory under the assumption that the generation amount of the thermal lens is the same. In particular, compared with the conventional one-way excitation, the two-way excitation can reduce the total amount of generated thermal lenses by dispersing the excitation light. Thereby, in the two-way excitation, even if the excitation density is increased, it is possible to realize a thermal lens generation state equivalent to the conventional one-way excitation, and it is possible to suppress the reflectance of the output mirror correspondingly. In this way, it is possible to dissipate heat using two-way excitation and excite it by a correspondingly high density, which can further reduce the reflectivity of the output mirror, and reduce the energy accumulated in the resonator. Can be suppressed.
(Mode matching)

Further, by making the spot diameter of the excitation light smaller than the TEM ₀₀ beam mode of the solid-state laser medium in the two-way excitation, it is possible to further increase the efficiency. In the conventional bi-directional excitation, the excitation is narrowly excited by slightly increasing the spot diameter of the excitation light to be irradiated on each end face of the solid-state laser medium from the size of the TEM ₀₀ mode diameter of the solid-state laser medium. The problem that the thermal lens and the hot lens effect are generated by concentrating on the range was avoided. However, this method can cope with the case where the output of the LD unit is low, but it is difficult to increase the gain in the solid-state laser medium crystal when the high output LD unit is used. Therefore, the gain generated inside the solid-state laser crystal is increased by performing high-density excitation with an excitation spot diameter narrower than the TEM ₀₀ mode generated inside the resonator.

More specifically, the TEM ₀₀ beam mode is a mode that can oscillate a single wavelength (single mode). By oscillating laser in this mode, the phase of the laser output light is aligned and high quality output without disturbance Light can be obtained. To obtain a TEM ₀₀ mode, using an aperture or the like, to excite only the area of the TEM ₀₀ mode at the end face of the solid-state laser medium. Here, according to the conventional idea, it is considered that a thermal lens is likely to be generated when excited in a narrow region. Also, once a thermal lens is generated, the output light spreads due to the thermal lens effect even if it is condensed by an aperture or the like and set in the TEM ₀₀ mode. For this reason, it has been practiced to avoid a thermal lens by exciting slightly larger than the TEM ₀₀ mode. However, when excited over a wide area, single mode to multi-mode are mixed. On the other hand, if the spot diameter is reduced and excited, a thermal lens is generated as described above, and a single mode cannot be obtained. For example, if the laser processing apparatus has a low output of about 2 to 3 W, a single mode can be obtained even if it is excited finely. However, when the output is 10 W class, a single mode cannot be obtained due to the influence of heat if it is excited finely. Therefore, by adopting the two-way excitation method as described above, the concentration of heat is alleviated. As a result, even if excitation is performed with a narrow spot diameter, excitation can be performed in a single mode. As described above, by using two-way excitation and spot diameter adjustment in combination, it is possible to enhance and excite only a necessary region, and to obtain high-efficiency and high-quality laser output light. For example, in the conventional method, a 9 W resonator output is obtained at the input of the 30 W LD unit, but in this embodiment, the efficiency is improved by combining two-way excitation and mode matching, and the 40 W LD unit is improved. A resonator output with an average output of 10 W or more and a peak power of 30 kW or more can be obtained at the input. Further, the average output can be 15 W and the peak power can be 100 kW.
Furthermore, the TEM ₀₀ mode spot diameter is 1.3 or less to enable single mode output. In addition, the laser output light is suppressed to a TEM ₀₀ mode spot diameter of 1.3 or less in the entire output range of 0.5 W to 15 W. be able to.

The spot diameter is adjusted with a condenser lens. The condensing lens condenses the parallel light reflected by the reflecting mirror or reflected or transmitted by the branching means 23 to a predetermined spot diameter, and puts it on the end face of the solid-state laser medium.
(Laser beam scanning system 30)

  Processing is performed by scanning the laser output light generated by the laser resonator as described above into a work area on the workpiece W with a desired processing pattern by the laser beam scanning system 30. The laser resonator 20 and the laser beam scanning system 30 are optically connected. For example, the laser output light emitted from the output mirror 26 in FIG. 3 is folded and transmitted to the laser beam scanning system 30 disposed below.

  The laser beam scanning system 30 includes a scanner that reflects and outputs the laser beam in a desired direction, and scans and processes the laser output beam on the surface of the workpiece W. Each scanner has a galvano mirror which is a total reflection mirror as a reflecting surface for reflecting light, a galvano motor for rotating with the galvano mirror fixed to the rotating shaft, and a position where the rotating shaft rotates. A position detector for outputting as a signal is provided. The scanner is connected to a scanner driving unit 35 that drives the scanner. The scanner driving unit 35 is connected to the control unit 50, receives a control signal for controlling the scanner from the control unit 50, and drives the scanner based on the control signal. For example, the scanner drive unit 35 adjusts the drive current for driving the scanner based on the control signal. The scanner driving unit 35 includes an adjustment mechanism that adjusts a temporal change in the rotation angle of each scanner with respect to the control signal. The adjustment mechanism is configured by a semiconductor component such as a variable resistor that adjusts each parameter of the scanner driving unit 35.

  The laser beam scanning system 30 shown in FIG. 1 includes a pair of an X-axis scanner 31 and a Y-axis scanner 32, and galvano motors 33 and 34 that rotate them. The galvano motors 33 and 34 are driven by a scanner driving unit 35. The scanner driving unit 35 drives the galvano motors 33 and 34 based on the scanning signal given from the control unit 50, so that the X-axis scanner 31 and the Y-axis scanner 32 provided on the output shafts of the galvano motors 33 and 34. The total reflection mirror is rotated, and the laser output light oscillated from the solid-state laser medium 21 is deflected and scanned. The deflected / scanned laser output light is irradiated and marked on the surface of the workpiece W through a work area condensing unit 40 provided in a substantially deflecting direction. The work area condensing unit 40 is provided so that the laser output light deflected in a state where the scanner is in the neutral position is incident on the center as parallel light.

The work area condensing unit 40 uses a work area condensing lens such as an fθ lens. After the laser beam is reflected by the galvanometer mirror, it is condensed by the work area condensing lens and irradiated on the irradiation surface. As shown in FIG. A beam expander 36 is placed in front of the galvanometer mirror so that the beam diameter of the laser beam output from the laser oscillation unit 50 is expanded. The outgoing beam from the beam expander 36 is reflected by an optical member such as a mirror and guided to the galvanometer mirror of the laser beam scanning system 30. The work area condensing unit such as the fθ lens can be omitted by substituting the function of the Z-axis scanner as described later.

  An example of the laser beam scanning system 30 is shown in FIG. 24, FIG. 25, and FIG. In these drawings, FIG. 24 is a perspective view showing the configuration of the laser beam scanning system 30 of the laser processing apparatus, FIG. 25 is a perspective view of FIG. 24 viewed from the reverse direction, and FIG. 26 is a side view. Yes. The laser processing apparatus shown in these drawings includes a beam expander 36 that incorporates a Z-axis scanner whose optical path coincides with a laser resonator 20 that generates laser output light, an X-axis scanner 31, and an X-axis scanner 31. And a Y-axis scanner 32 arranged to do so. The laser beam scanning system 30 causes the laser output light emitted from the laser resonator 20 to be scanned two-dimensionally within the work area WS by the X-axis scanner 31 and the Y-axis scanner 32, and further the height by the Z-axis scanner 37. The working distance, that is, the focal length can be adjusted in the direction, and processing can be performed three-dimensionally. Needless to say, the X-axis scanner, the Y-axis scanner, and the Z-axis scanner can function similarly even if they are interchanged. For example, the laser output light emitted from the Z-axis scanner may be received by the Y-axis scanner, or the Y-axis may be controlled by the X-axis scanner and the Z-axis may be controlled by the Y-axis scanner. In these drawings, the fθ lens which is a work area condensing lens is not shown.

  In general, in a laser processing apparatus, a work area condensing lens such as an fθ lens is provided between the Y axis scanner and the work area in order to collect the laser output light reflected by the Y axis scanner so as to irradiate the work area. Is arranged. The fθ lens performs correction in the Z-axis direction. Specifically, as shown in FIG. 27A, the focal position is extended as it approaches the end of the work area WS, and is corrected to be positioned on the processing target surface of the workpiece W. Since the focus position of the laser output light is an arc-shaped locus, when the processing target surface is a plane, the focus position is adjusted so that the focus position is at a position vertically below, the center of the plane WM indicating the processing target surface in FIG. When set, the farther away from the center, that is, the closer to the periphery of the work area WS, the farther the focal position is from the surface to be processed (laser output light LB ′), and the processing accuracy is lowered because the focus is not achieved. Therefore, as shown in FIG. 27 (b), correction is performed by the fθ lens so that the focal position of the laser output light LB becomes longer as it approaches the end of the work area WS. The focal position of the laser output light LB can be positioned on the plane WM by virtually converting the plane WM of the processing target surface into a convex curved correction surface indicated by WM ′.

  In the laser processing apparatus, for example, when it is desired to form a beam having a spot diameter smaller than about 50 μm, it is preferable to arrange an fθ lens. On the other hand, when a beam diameter larger than the small spot diameter described above and having a spot diameter of about 100 μm (usually used spot diameter) is adopted, the Z-axis assembly provided in the beam expander on the Z-axis scanner side is used. By moving the optical lens in the Z-axis direction, correction in the Z-axis direction that should be performed by the fθ lens can be performed as correction control. Thereby, when the spot diameter is large, the fθ lens can be omitted. In the example of FIG. 27A described above, correction in the Z-axis direction to be performed by the fθ lens is performed by correction control of the Z-axis scanner. On the other hand, when the spot diameter is small, the focus position is not sufficiently adjusted by the correction by the Z-axis scanner, so the fθ lens is used as described above. In this embodiment, there are three types of spot diameters of laser output light: small spot, standard, and wide spot. Only the small spot type of these is used to correct distortion at the end of the work area WS with the fθ lens. In standard and wide spots, the fθ lens is not used, and correction is performed by a Z-axis scanner.

Even when correction control in the Z-axis direction is performed by the Z-axis condenser lens provided in the beam expander of the Z-axis scanner, correction similar to the correction by the fθ lens described above is performed. The height of the correction surface WM ′ described in FIG. 27B, that is, the Z coordinate is uniquely determined by the XY coordinate. Therefore, by associating the corrected Z coordinate for each XY coordinate, if the Z-axis scanner is moved to the associated Z-coordinate according to the movement of the XY-axis scanner, processing at the focal position can always be performed. Become. The association data is stored in the storage unit 72 of the laser processing data setting device shown in FIG. Alternatively, the data can be stored and transferred to the memory unit 52 provided in the laser control unit 1 of the laser processing apparatus. As a result, the corrected Z coordinate is determined following the movement of the XY coordinate in the work area, so that it is possible to irradiate the laser output light whose focal position is adjusted almost uniformly in the work area.
(Z-axis scanner 37)

  The Z-axis scanner 37 constitutes a beam expander 36 that adjusts the spot diameter of the laser output light and thereby adjusts the focal length. That is, by changing the relative distance between the entrance lens and the exit lens by the beam expander 36, the beam diameter of the laser output light can be enlarged / reduced, and the focal position can also be changed. The beam expander 36 is arranged in front of the galvanometer mirror as shown in FIG. 24 and adjusts the beam diameter of the laser output light output from the laser resonator 20 so as to effectively collect light on a small spot. In addition, the focal position of the laser output light can be adjusted. A method for adjusting the working distance by the Z-axis scanner 37 will be described with reference to FIGS. 29 and 30 are side views of the laser beam scanning system 30. FIG. 29 shows a case where the focal length of the laser output light is increased, and FIG. 30 shows a case where the focal length is shortened. FIG. 31 shows a front view and a sectional view of the Z-axis scanner 37. As shown in these figures, the Z-axis scanner 37 includes an incident lens 38 facing the laser resonator 20 side and an exit lens 39 facing the laser exit side. It can change. In the example of FIGS. 29 to 31, the exit lens 39 is fixed, and the entrance lens 38 can be slid along the optical axis direction by a drive motor or the like. FIG. 31 shows the drive mechanism of the incident lens 38 with the illustration of the exit lens 39 omitted. In this example, the movable element can be slid in the axial direction by a coil and a magnet, and the incident lens 38 is fixed to the movable element. However, the incident lens side can be fixed and the exit lens side can be moved, or both the entrance lens and the exit lens can be moved.

  As shown in FIG. 29, when the distance between the incident lens 38 and the outgoing lens 39 is made closer, the focal position becomes farther and the focal distance (working distance) becomes larger. On the contrary, as shown in FIG. 30, when the distance between the incident lens 38 and the outgoing lens 39 is increased, the focal position approaches and the focal distance becomes smaller.

Note that the laser processing apparatus capable of three-dimensional processing, that is, processing in the height direction of the workpiece, is not limited to the method of adjusting the Z-axis scanner as shown in FIGS. It is also possible to use other methods such as moving the lens, moving the laser output unit or the marking head itself, or moving the stage on which the workpiece is placed.
(Distance pointer)

  Further, in order to adjust the focal position at the center of the work area of the laser processing apparatus capable of three-dimensional processing, a guide pattern indicating the irradiation position when the laser output light is scanned into the work area WS can be displayed. The laser beam scanning system 30 of the laser processing apparatus shown in FIGS. 24 to 25 serves as a distance pointer to align the guide light source 64 and the guide light GL from the guide light source 64 with the optical axis of the laser beam scanning system 30. And a pointer light source 66 for irradiating pointer light PL as a pointer light adjustment system, and a pointer scanner mirror formed on the back surface of the Y-axis scanner 32. 68 and a fixed mirror 67 for further reflecting the pointer light PL from the pointer light source 66 reflected by the pointer scanner mirror 68 and irradiating it toward the focal position. The distance pointer is adjusted by irradiating the pointer light PL indicating the focal position of the laser output light from the pointer light source 66 and irradiating the pointer light PL almost at the center of the guide pattern displayed by the guide light GL. The focal position of the laser output light is indicated.

  In the above example, the laser beam scanning system 30 is provided with a mechanism capable of adjusting the focal length of the laser output light, thereby enabling three-dimensional processing. However, it is also possible to adjust the height of the stage so that the focus of the laser output light is tied to the work surface of the work by making the position of the stage on which the work is placed vertically adjustable. Three-dimensional processing can also be performed. Also, by making the stage movable in the X-axis or Y-axis direction, the corresponding scanner of the laser beam scanning system can be omitted. These configurations can be suitably used not only in a form in which the workpiece is conveyed on the line but also in a form in which the work is placed on the stage and processed.

  According to the above configuration, the laser output light obtained by the laser resonator by the laser light scanning system 30 can be scanned three-dimensionally in the work area. Further, by controlling the movement amount of the Z-axis scanner, which is generally inferior in response characteristics as compared to the XY-axis scanner, three-dimensional processing with higher speed and higher controllability is possible. In addition, while correcting with the Z-axis scanner so that the focal length at each position in the work area is kept constant, this correction is interrupted while the emission of the laser output light is OFF, and generally response characteristics compared with the XY-axis scanner. The amount of movement of the inferior Z-axis scanner can be suppressed, and three-dimensional machining with higher speed and higher controllability is possible. Furthermore, adjustment is made by the Z-axis scanner so that the focal position becomes substantially uniform in the work area, and it is possible to prevent a reduction in processing accuracy near the edge of the work area without preparing a separate work area condenser lens. In addition, the next machining start can be smoothly performed by prefetching the Z coordinate of the next machining start position and moving it to this position. Alternatively, the follow-up operation of the Z-axis scanner can be interrupted and held at a fixed position, so that the XY-axis scanner can move to the next processing position at a high speed regardless of the response time of the Z-axis scanner, and the entire scan can be performed. The speed is improved.

On the other hand, since the spread angle of the emitted light changes due to the thermal lens characteristics of the solid-state laser medium, there arises a problem that the focal position at the processing point is shifted due to the power setting. By calculating this deviation, the deviation is corrected by the Z-axis scanner, and high-precision processing can be maintained even if a thermal lens is generated.
(System configuration of laser processing equipment)

  Next, FIG. 32 shows a system configuration of a laser processing apparatus capable of three-dimensional processing. The laser processing system shown in this figure is connected to a marking head 2A that constitutes a laser output unit, a controller 1A that is a laser control unit 1 that is connected to and controls the marking head 2A, and a controller 1A that is capable of data communication. And a laser processing data setting device 70 that sets a processing pattern as three-dimensional laser processing data for the controller 1A. The marking head 2A and the controller 1A constitute a laser processing apparatus 100. In the example of FIG. 32, the laser processing data setting device 70 installs a laser processing data setting program in a computer to realize a laser processing data setting function. The laser processing data setting device can use a programmable logic controller (PLC) connected with a touch panel, other dedicated hardware, etc. in addition to a computer. The laser processing data setting device can also function as a control device that controls the operation of the laser processing device. For example, a function as a laser processing data setting device and a function as a controller of a laser output unit including a laser output unit may be integrated into one computer. Further, the laser processing data setting device is constituted by a member different from the laser processing device, and can also be integrated into the laser processing device, for example, a laser processing data setting circuit incorporated in the laser processing device.

Furthermore, various external devices 80 can be connected to the controller 1A as necessary. For example, an image recognition device such as an image sensor for confirming the type and position of a workpiece conveyed on the line, a distance measuring device such as a displacement meter for obtaining information on the distance between the workpiece and the marking head 2A, and a device according to a predetermined sequence It is possible to install a PLC that controls the above, a PD sensor that detects the passage of a workpiece, and other various sensors, and to be connected so that data communication is possible.
(Laser processing data setting device)

  Laser processing data that is setting information for processing planar processing data into a three-dimensional shape is set by a laser processing data setting device 70. FIG. 28 shows a block diagram as an example of the laser processing data setting device 70. The laser processing data setting device 70 shown in this figure includes an input unit 4 for inputting various settings, and an arithmetic unit constituting processing data generating means for generating laser processing data based on information input from the input unit 4. 71, a display unit 5 for displaying setting contents and post-calculation laser processing data, and a storage unit 72 for storing various setting data. The display unit 5 displays the image of the marking head 2A when displaying the image of the processing target surface three-dimensionally on the processing image display unit and the processing image display unit. Displayable head image display means is provided. The input unit 4 is a machining condition setting unit for inputting machining conditions to be machined with a desired machining pattern, and a machining surface profile input unit for inputting profile information indicating a three-dimensional shape of the workpiece machining surface, A machining pattern input means for inputting pattern information, a plurality of machining blocks set in a work area, a machining block setting means capable of setting a machining pattern for each machining block, and a plurality of blocks set by the block setting means The function of the group setting means for setting the process group which put the process block together, and the position adjustment means which can adjust the position of the process pattern arrange | positioned on a process target surface is implement | achieved. The machining surface profile input means further includes a basic graphic designating means for designating a basic graphic representing the machining target surface, and a three-dimensional shape data input means for inputting the three-dimensional shape data representing the machining target surface from the outside. Is realized. The storage unit 72 corresponds to the memory unit 52 in FIG. 1 and is a member that stores information such as profile information and machining pattern information set by the input unit 4. A storage medium such as a fixed storage device, a semiconductor memory, or the like is used. Available. In addition to providing a dedicated display, the display unit 5 may use a computer monitor connected to the system. The machining conditions set by the laser machining data setting device 70 include, in addition to machining power (laser output) and scan speed (scanning speed), working distance, defocus amount, spot diameter, and workpiece type (iron Black processing on stainless steel, black processing on stainless steel, workpiece material such as ABS resin, polycarbonate resin and phenol resin, and processing purpose such as resin welding and surface roughening). A plurality of processing blocks may be set, and processing pattern information may be set for each processing block. In particular, in laser processing equipment that can achieve laser output light with excellent rise characteristics, the power of the laser output light and the setting items such as workpiece material, processing pattern, finishing state, and processing time for each processing block The beam diameter can be freely changed. Furthermore, the processing parameters of the processing conditions once set can be saved as setting data and recalled when necessary.

  In a general laser beam scanning system, the response characteristics of the scanner, that is, the response time required to actually complete the operation after the operation instruction is given to the scanner may differ depending on the scanner. For example, in a laser processing apparatus capable of three-dimensional processing having an X, Y, and Z axis scanner, the response characteristics of the Z axis scanner tend to be inferior as compared to the X and Y axis scanners. For example, as shown in FIG. 24 and the like, an X / Y-axis scanner scans with a mirror rotated by a galvano scanner, whereas a Z-axis scanner has a mechanism for translating the lens itself in the optical axis direction. For this reason, the Z-axis scanner is disadvantageous in response characteristics of the Z-axis scanner compared to the X / Y-axis scanner due to the operation mechanism that converts the rotational motion using the motor into the parallel movement. The Z-axis scanner can be driven by a cylinder, a piston or the like without using a motor, but this case is also disadvantageous in terms of response speed compared to the X / Y-axis scanner. As a result, the response time of the Z-axis scanner driving motor lags behind that of the X / Y-axis scanner, so that a waiting time occurs in the scanner control. Therefore, the control unit 50 selects an optimal movement path according to the machining pattern so as to select an appropriate movement path according to the response characteristics of the scanner used, the shape of the workpiece, and the like. Preferably, a high-speed movement can be realized by selecting a path that refrains from using a scanner with poor response performance as much as possible.

  Further, the optical characteristics can be corrected as shown in FIG. 27 with a Z-axis scanner. That is, even when the focal position is corrected by the fθ lens using the Z-axis scanner, the tracking function of the Z-axis scanner can be used by associating the Z coordinates. Even in this case, by turning off the tracking function when the output of the laser output light is turned off, an extra waiting time can be omitted, the response characteristics can be improved, and the time required for processing can be shortened. In this way, the Z-axis trajectory is changed according to the output ON / OFF of the laser output light, and the processing time can be shortened by eliminating unnecessary movement in the Z direction especially when the output is OFF. Driving can be realized.

The laser marker of the present invention, for example marking, drilling, trimming, scribing, surface treatment, material processing, spectroscopy, wafer inspection, medical diagnosis, laser printing and the like, are widely applicable in the process of performing laser irradiation, the fine semiconductor such as It can be used for applications such as processing, display repair, and trimming systems.

It is a block diagram which comprises the laser processing apparatus which concerns on Embodiment 1 of this invention. It is a perspective view which shows the internal structure of the laser excitation part of FIG. 6 is a plan view showing an arrangement example of optical system members of a laser resonator according to Embodiment 1. FIG. 6 is a plan view showing an arrangement example of optical system members of a laser resonance unit according to Embodiment 2. FIG. 6 is a plan view showing an arrangement example of optical system members of a laser resonator according to Embodiment 3. FIG. FIG. 10 is a plan view showing an arrangement example of optical system members of a laser resonator according to a fourth embodiment. FIG. 10 is a plan view showing an arrangement example of optical system members of a laser resonator according to a fifth embodiment. FIG. 10 is a plan view illustrating an arrangement example of optical system members of a laser resonator according to a sixth embodiment. FIG. 10 is a plan view showing an arrangement example of optical system members of a laser resonator according to a seventh embodiment. FIG. 20 is a plan view showing an arrangement example of optical system members of a laser resonator according to an eighth embodiment. It is the top view which summarized the modification of the arrangement pattern of an optical system member. It is the top view which summarized the other modification of the arrangement pattern of an optical system member. It is the top view which put together the further modification of the arrangement pattern of an optical system member. Nd: In YVO ₄ crystal is a graph showing changes in absorption efficiency for the wavelength of the excitation light. It is the graph which compared the change of the laser output light with respect to the wavelength of an excitation source by 1 direction excitation and 2 direction excitation. It is the graph which compared the time change of the laser output light by 1 direction excitation and 2 direction excitation. It is a graph which shows the time change of the laser output light at the time of changing the electric current of an excitation source from 0A to 45A in bi-directional excitation. It is the graph which measured the laser output light with respect to the power of an excitation light source according to the reflectance of a beam splitter at the time of CW operation | movement of a two-way excitation system. It is the graph which measured the laser output light with respect to the power of an excitation light source according to the reflectance of a beam splitter at the time of Q switch operation | movement of a two-way excitation system. It is a schematic diagram which shows the type | formula which calculates the energy inside a resonator. It is a graph which shows the change of the laser output with respect to the reflectance of the output mirror in a two-way excitation system. It is a graph which shows the change of the resonator internal energy with respect to the reflectance of an output mirror. It is the graph which measured the laser output light with respect to the power of the excitation light source at the time of the CW operation | movement of a two-way excitation system in the case where the reflectance of a beam splitter is high and low. It is a perspective view which shows the structure of the laser output part containing the laser beam scanning system of a laser processing apparatus. It is the perspective view which looked at FIG. 24 from the back direction. It is the side view which looked at FIG. 24 from the side. It is explanatory drawing explaining the state from which the focus position of the laser output light of a laser processing apparatus changes in a work position. It is a block diagram which shows a laser processing system. It is a side view which shows the laser beam scanning system in the case of lengthening a focal distance. It is a side view which shows the laser beam scanning system in the case of shortening a focal distance. It is the front view and sectional drawing which show a Z-axis scanner. It is a block diagram which shows the system configuration | structure of the laser processing apparatus which can be processed three-dimensionally. It is a block diagram which shows the structure of the laser processing apparatus by the conventional end pumping system. It is a block diagram which shows the structure of a two-way excitation system.

DESCRIPTION OF SYMBOLS 100 ... Laser processing apparatus 1 ... Laser control part; 1A ... Controller 2 ... Laser output part; 2A ... Marking head 3 ... Excitation light transmission medium; 4 ... Input part; 5 ... Display part 10 ... Laser excitation part 11 ... Excitation light source; DESCRIPTION OF SYMBOLS 12 ... Excitation light condensing part; 13 ... Excitation casing; 14 ... Optical fiber 20, 201-208 ... Laser resonance part; 21 ... Solid laser medium 22 ... Excitation light coupling means; 22a ... Optical fiber coupling part; 23: Branch means 24: First dichroic mirror; 25: Second dichroic mirror 26 ... Output mirror; 27 ... Aperture; 28 ... Q switch 30 ... Laser beam scanning system 31 ... X-axis scanner; 32 ... Y-axis scanner; 34 ... Galvano motor 35 ... Scanner drive unit; 36 ... Beam expander; 37 ... Z-axis scanner 38 ... Incident lens; 39 ... Out Lens 40 ... Condensing unit; 50 ... Control unit 52 ... Memory unit; 54 ... Power supply circuit 61 ... First condensing lens; 62 ... Second condensing lens; 63 ... Structural substrate 64 ... Light source for guide; 65 ... Half mirror 66 ... Pointer light source 67 ... Fixed mirror; 68 ... Pointer scanner mirror 70 ... Laser processing data setting device 71 ... Calculation unit; 72 ... Storage unit; 80 ... External device 901 ... Laser control unit; 902 ... Laser output unit; 904: input unit; 910: laser excitation unit 918 ... output coupler; 920 ... laser resonator; 921 ... solid laser medium; 928 ... LD
930 ... Laser beam scanning system; 932 ... Optical fiber; 936 ... Beam expander 940 ... Work area condensing unit LB, LB '... Laser output light; PL ... Pointer light; GL ... Guide light W ... Work; WS ... Work area WM: plane to be processed; WM ′: correction surface R1: first excitation light ; R2: second excitation light B: branch path; B1: first branch path; B2: second branch path RM: rear side Mirror: FM ... Exit-side mirror BS, BS1-BS8 ... Beam splitters M1, M11-M18 ... First reflection mirror M2, M21-M28 ... Second reflection mirror M3, M31-M38 ... Third reflection mirror

Claims (9)

A laser controller for generating excitation light;
An excitation light transmission medium for transmitting excitation light generated by the laser control unit to a laser output unit described later;
A laser output unit including a laser light scanning system for scanning laser light generated by laser oscillation based on excitation light transmitted by the excitation light transmission medium;
A laser marker with a,
The laser output unit,
A crystalline solid-state laser medium extending in one direction and having two end faces, wherein the pumping light transmitted by the pumping light transmission medium is input from both end faces to cause laser oscillation; and As an end face,
A first end face constituting an incident surface of excitation light;
A second end surface that is opposite to the first end surface and forms an excitation light incident surface and an excitation light extraction surface;
A solid state laser medium comprising:
Splits the pumping light transmitted by the excitation light transfer medium, the two second excitation light traveling in the first excitation light and second branch path travels first branch path, said solid state laser from the first branch path a first pump light of the first end surface to the excitation light of the medium, the second excitation light from the second branch path to a second end surface, Ru is respectively incident to first excitation light is larger than the second excitation light Branching means;
A first dichroic mirror disposed on the first branch path so as to face the first end face and transmitting excitation light and reflecting laser oscillation light toward the first end face;
A second dichroic mirror that is disposed on the second branch path so as to face the second end face, transmits excitation light, and reflects laser oscillation light toward an output mirror described later;
An output mirror that is disposed at a position that does not interfere with the branch path and is separated from the second dichroic mirror in a direction substantially orthogonal to the one direction, and for outputting reflected light reflected by the second dichroic mirror; ,
A Q switch disposed between the second dichroic mirror and the output mirror for controlling ON / OFF of laser output;
With
The distance between the solid-state laser medium and the first dichroic mirror is shorter than the distance between the second dichroic mirror and the output mirror, and the first excitation light incident on the first end face is the second end face. the laser marker characterized by comprising configured to be larger than the second excitation light is incident on. A laser marker according to claim 1,
The laser marker and characterized by being set to 1: the branch unit, the ratio for branching incident light into the first excitation light and second excitation light, approximately 2: 1 to approximately 4. A laser marker according to claim 1 or 2,
The laser marker, characterized in that YVO a ₄ crystal: the solid-state laser medium is Nd. A laser marker as claimed in any one of 3,
The laser marker, wherein the reflectivity of the output mirror is 30% to 70%. A laser marker as claimed in any one of 4,
The laser marker, wherein the average output of the semiconductor laser as the excitation light source is 10W or more. A laser marker according to any one of claims 1-6, further
The first end face is irradiated with the first excitation light of the excitation light that is disposed opposite to the solid-state laser medium on the first branch path so as to face the first dichroic mirror and that has passed through the first dichroic mirror. spot diameter during comprises a first condenser lens causes condensing the excitation light to be smaller than TEM ₀₀ mode of the solid-state laser medium,
The second end face is irradiated with the second excitation light of the excitation light that is disposed on the opposite side of the solid-state laser medium on the second branch path so as to face the second dichroic mirror and that has passed through the second dichroic mirror. spot diameter during comprises a second condensing lens causes condensing the excitation light to be smaller than TEM ₀₀ mode of the solid-state laser medium,
Equipped with a,
The first end surface of said solid-state laser medium, the solid excitation light of a small spot diameter than the laser medium TEM ₀₀ mode is turned, and, on the second end surface of said solid-state laser medium, TEM ₀₀ mode of the solid-state laser medium the laser marker, wherein Rukoto such are configured to solid-state laser medium is excited is turned excitation light of a small spot diameter than. A laser marker according to any of claims 1 7,
The laser output unit further includes
A first reflection mirror that reflects the first excitation light or the second excitation light branched by the branching unit substantially vertically;
A second reflecting mirror that further reflects the reflected light reflected by the first reflecting mirror or the second excitation light or the first excitation light branched by the branching means in a substantially vertical direction;
A third reflecting mirror for reflecting the reflected light reflected by the second reflecting mirror substantially vertically;
With
The branch path constituted by the first branch path and the second branch path is configured in a rectangular shape by the branching means, the first reflecting mirror, the second reflecting mirror, and the third reflecting mirror, and any one of the rectangular shapes The solid-state laser medium and the first and second dichroic mirrors are disposed on the side,
In addition, any one of the vertices of the rectangular shape is arranged so that the excitation light from the excitation light source is incident on an extension line of any one of the rectangular shapes forming the vertex. laser marker. A laser marker according to any one of claims 1-8, further
Excitation light coupling means for optically coupling the excitation light transmission medium with the branching means;
An aperture disposed between the second dichroic mirror and the output mirror for shaping laser oscillation light;
The laser marker, characterized in that it comprises a. A laser marker according to any one of claims 1-9,
The laser output scanning system of the laser output unit includes an entrance lens and an exit lens, and the entrance lens and the exit lens are aligned with the optical axes of the laser light emitted from the laser resonator. A Z-axis scanner capable of adjusting the focal length of the laser beam by changing the relative distance between the lens and the exit lens along these optical axes;
An X-axis scanner or a Y-axis scanner for scanning the laser beam transmitted through the Z-axis scanner in the X-axis direction or the Y-axis direction;
A Y-axis scanner or an X-axis scanner for scanning a laser beam scanned by the X-axis scanner or the Y-axis scanner in the Y-axis direction or the X-axis direction;
The laser marker, characterized in that it comprises a.

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