JP2008055436A - Laser beam irradiation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser beam irradiation device capable of stabilizing characteristics of a laser beam emitted to a material to be irradiated and also stabilizing a machining accuracy. <P>SOLUTION: This laser beam irradiation device is provided with: a stage which is provided two-dimensionally movably and on which the material 6 to be irradiated is placed; laser beam oscillator for oscillating the laser beam 20 which is emitted to the material 6 to be irradiated by the laser beam; lens 5 which is arranged on a laser beam route on which the laser beam 20 reaches the material 6; optical axis shifting member 2a which is arranged a laser beam route between the laser beam oscillator and the lens 5 and with which the position of the optical axis of the laser beam 20 is compensated; measuring instrument 3 with which the position of the optical axis on the laser beam route between the optical axis shifting member 2a and the lens 5 and control part 14 for controlling the optical axis shifting member 2a in accordance with the position of the optical axis which is measured with the measuring instrument 3. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a laser irradiation apparatus, and more particularly to a laser irradiation apparatus that performs high-precision and high-efficiency processing by irradiating a processing target placed on a movable stage with laser light.

  In recent years, processing using a laser has been widely used for various applications in various industrial fields such as welding / cutting processing, fine drilling of electronic parts, and production of liquid crystal / semiconductor devices. Along with this, many techniques related to components constituting the laser irradiation apparatus have been proposed for the purpose of improving the efficiency and accuracy of laser processing.

  For example, there has been proposed a laser processing apparatus that controls the position of a laser beam so that the laser irradiation position on the substrate is always within a certain range (see, for example, Patent Document 1). In order to adjust the optical axis of the laser beam, a laser processing apparatus that detects the position of the laser beam and tilts or moves the mirror so that the irradiation position of the laser beam becomes a predetermined position has been proposed (for example, a patent) Reference 2). In addition, laser oscillators have been increased in output for the purpose of improving processing efficiency and processing large parts. As for the optical system, a technique for improving the efficiency and accuracy of processing using a diffractive lens has been proposed.

  FIG. 11 is a schematic diagram showing a configuration of a conventional laser irradiation apparatus. As shown in FIG. 11, the laser irradiation apparatus includes a stage 7, a laser oscillator 1, a mirror 4, and a lens 5. The mirror 4, the lens 5, and the stage 7 are installed on a structure that is supported by the surface plate 10. The surface plate 10 is fixed to the floor surface 13 by a base leg 12, and a vibration absorbing member 11 is provided between the base leg 12 and the surface plate 10. The vibration absorbing member 11 absorbs the vibration of the floor surface 13 and acts so that the vibration of the floor surface 13 generated when a person walks around is not transmitted to the stage 7. On the other hand, the laser oscillator 1 is disposed independently of the structure and is fixed to the floor surface 13.

  The stage 7 is installed above the surface plate 10 with a linear motion member 8 interposed therebetween. The linear motion member 8 is provided so as to be movable in the left-right direction in FIG. Further, the stage 7 is provided so as to be movable in the depth direction of FIG. 11 by other linear motion members (not shown) and other linear motion guides. That is, the stage 7 is provided so as to be movable two-dimensionally. On the surface of the stage 7, a workpiece to be irradiated with the laser, that is, a laser irradiated object 6 is placed. The laser oscillator 1 oscillates a laser beam applied to the laser irradiation object 6. The lens 5 is arranged in a laser path where the laser light oscillated from the laser oscillator 1 reaches the laser irradiated object 6, condenses the laser light incident on the lens 5 and irradiates the laser irradiated object 6. .

In FIG. 11, the linear motion member 8 is in the center of the surface plate 10, and this state is set as a reference position. At this time, the center of gravity of the structure supported by the surface plate 10 is at the G0 position. The angle of the mirror 4 with respect to the surface on which the laser irradiated object 6 of the stage 7 is placed is 45 °. When the linear motion member 8 is at the reference position, the angle of the mirror 4 with respect to the horizontal plane is 45 °. The laser light oscillated from the laser oscillator 1 is horizontal until it enters the mirror 4, is reflected by the mirror 4, is bent by 90 °, and enters the center of the lens 5 perpendicularly. The laser beam condensed by the lens 5 is irradiated to the laser irradiation object 6 placed on the stage 7.
Japanese Patent No. 2583036 Japanese Patent Laid-Open No. 11-58052

  In order to achieve both the enlargement of the laser oscillator and the laser irradiated object and the high accuracy of laser processing, it is necessary to solve conflicting problems. That is, in laser processing, generally, the laser irradiated object and the laser beam are moved relative to each other for positioning and processing, but the laser irradiated object and the laser beam are increased due to the increase in size and mass of the laser irradiated object. The movable stage for relative movement between the two is also enlarged. Therefore, when the stage is moved, the stage is shaken or tilted due to a change in the position of the center of gravity of the structure including the stage.

  FIG. 12 is a schematic diagram showing a state in which the stage is inclined. FIG. 13 is a schematic diagram illustrating the tilt angle of the stage. As shown in FIG. 12, in the laser irradiation apparatus described in FIG. 11, the linear motion member 8 on which the stage 7 is installed is supported by the surface plate 10 by moving from the center (reference position) of the surface plate 10. The center of gravity of the structure is moved from the G0 position to the G2 position. The stage 7 is tilted by a change in the center of gravity of the structure including the stage 7. That is, as shown in FIG. 13, as the linear motion member 8 on which the stage 7 is installed moves, the stage 7 before the linear motion member 8 moves is substantially horizontal as indicated by a broken line in FIG. On the other hand, the stage 7 after the movement of the linear motion member 8 is inclined as shown by a solid line in FIG. The angle formed by the surface of the stage 7 after the movement of the linear motion member 8 with respect to the surface on which the laser irradiated object 6 of the stage 7 is placed before the linear motion member 8 is moved is defined as the angle of the stage 7. The inclination angle. θ represents the magnitude of the tilt angle.

  As shown in FIG. 12, as the stage 7 is tilted, the angle at which the laser light enters the lens 5 is tilted. As a result, the laser beam does not enter the center of the lens 5 for condensing the laser beam on the laser irradiated object 6. For example, as shown in FIG. 12, since the stage 7 is inclined, the laser beam may be incident on the lens 5 with a deviation of δA from the center of the lens 5.

  As a result of the laser beam not being incident on the center of the lens, the characteristics of the laser beam irradiated to the laser irradiation object are deteriorated, causing a reduction in processing accuracy. In particular, when a diffractive lens is used, in order to obtain a desired processing accuracy, it is necessary to position the laser beam and the center of the lens with higher accuracy than a refractive lens. As a countermeasure for this problem, the laser oscillator may be disposed on the structure including the stage together with the workpiece, but if the laser oscillator is large, it is extremely difficult to dispose the laser oscillator on the structure.

  Therefore, a main object of the present invention is to provide an object to be irradiated with a laser (laser object) even if the stage is shaken or tilted due to a change in the center of gravity of the structure including the stage when the stage is moved. An object of the present invention is to provide a laser irradiation apparatus capable of stabilizing the characteristics of laser light irradiated to an irradiation object and stabilizing processing accuracy.

  The laser irradiation apparatus according to the present invention includes a stage, a laser oscillator, a lens, an optical axis shift member, a measuring instrument, and a control unit. The stage is provided so as to be movable two-dimensionally, and a workpiece to be irradiated with a laser, that is, a laser irradiated object is placed on the surface of the stage. The laser oscillator is arranged independently of the stage and oscillates the laser light irradiated to the laser irradiation object. The lens is arranged in a laser path from which the laser light oscillated from the laser oscillator reaches the laser irradiation object, and condenses the laser light. The optical axis shift member is disposed in the laser path between the laser oscillator and the lens, and corrects the optical axis position of the laser light. The measuring instrument measures the optical axis position in the laser path between the optical axis shift member and the lens. The control unit controls the optical axis shift member in accordance with the optical axis position measured by the measuring instrument so as to cancel the change in the optical axis position of the laser light that occurs as the stage moves.

  In this case, even if the stage is shaken or tilted due to the change in the center of gravity of the structure including the stage when the stage is moved, and the optical axis position of the laser beam changes, the optical axis position is measured by the measuring instrument. Can be measured. Here, the optical axis is a straight line formed by the locus of the center of the laser beam. Since the change in the optical axis position of the laser beam can be corrected according to the measured optical axis position, adjustment can be made so that the laser beam is incident on the center of the lens. Therefore, it is possible to stabilize the characteristics of the laser beam irradiated to the laser irradiation object, and to stabilize the processing accuracy.

  Preferably, the laser irradiation apparatus further includes a deflector. The deflector is disposed in a laser path between the optical axis shift member and the lens, and adjusts a lens incident angle that is an angle at which the laser light is incident on the lens.

  In this case, in addition to correcting the change in the optical axis position of the laser light, the lens incident angle can be adjusted by the deflector. Therefore, adjustment can be made so that the laser light is incident on the center of the lens and along the normal line at the center of the lens. Therefore, it is possible to further stabilize the characteristics of the laser light irradiated to the laser irradiation object, and to further stabilize the processing accuracy.

  Preferably, the laser irradiation apparatus further includes a sensor capable of measuring an inclination angle. Here, the tilt angle refers to the angle formed by the stage surface after the movement when viewed from the surface on which the laser irradiation object of the stage before the movement is placed when the stage tilts as the stage moves. Show. Then, the control unit tilts the relative angle of the deflector with respect to the structure including the stage by θ / 2 in a direction opposite to the tilt angle direction with respect to the tilt angle having the magnitude of θ measured by the sensor. Control the deflector.

  In this case, the deflector can be controlled using the tilt angle measured by the sensor. Therefore, it can be adjusted more easily so that the laser beam is incident on the center of the lens and along the normal line at the center of the lens.

  Preferably, the optical axis shift member is provided so that a deflector incident angle which is an angle at which laser light enters the deflector can be adjusted. Then, the control unit controls the optical axis shift member so that the deflector incident angle is inclined by θ in the same direction as the inclination angle with respect to the inclination angle having the magnitude of θ measured by the sensor.

  In this case, the optical axis shift member can be controlled using the tilt angle measured by the sensor. Therefore, it can be adjusted more easily so that the laser beam is incident on the center of the lens and along the normal line at the center of the lens.

  Preferably, the optical axis shift member is a parallel plate. Then, the control unit controls the rotation angle around two orthogonal axes on the plane of the parallel plate where the laser light is incident on the parallel plate.

  In this case, by controlling the rotation angle around two orthogonal axes of the parallel plate against the change of the optical axis position of the laser beam due to the two-dimensional movement of the stage, the laser beam is centered on the lens with higher accuracy. It can adjust so that it may inject. Here, the parallel flat plate is a transparent member that has a parallel polished surface and has a single thickness and a refractive index and is capable of transmitting laser light.

  Preferably, the optical axis shift member is composed of two or more prisms. The control unit controls the rotation angle of the prism around the two orthogonal axes on the surface on which the laser light enters the prism.

  In this case, the laser beam is incident on the center of the lens with higher accuracy by controlling the rotation angle around the two orthogonal axes of the prism against the change in the optical axis position of the laser beam due to the two-dimensional movement of the stage. Can be adjusted.

  Preferably, the lens is a diffractive lens. In this case, the laser beam can be adjusted so that the laser beam is incident on the center of the lens by the optical axis shift member. Therefore, a diffractive lens that requires high-precision positioning between the laser beam and the lens center is used as the laser irradiation device. Can be used. By using a diffractive lens in a laser irradiation apparatus, it is possible to achieve higher processing efficiency and higher accuracy.

  As described above, in this laser irradiation apparatus, even if the stage is shaken or tilted due to the change in the center of gravity of the structure including the stage when the stage is moved, the laser beam irradiated to the laser irradiation object Can be stabilized, and machining accuracy can be stabilized.

  Embodiments of the present invention will be described below with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

(Embodiment 1)
FIG. 1 is a schematic diagram showing a configuration of a laser irradiation apparatus according to Embodiment 1 of the present invention. As shown in FIG. 1, the laser irradiation apparatus includes a stage 7, a laser oscillator 1, a lens 5, an optical axis shift member 2, and a measuring instrument 3. Further, a mirror 4 as a deflector is further provided. The optical axis shift member 2, the measuring instrument 3, the mirror 4, the lens 5, and the stage 7 are installed in a structure that is supported by the surface plate 10. The surface plate 10 is fixed to the floor surface 13 by a base leg 12, and a vibration absorbing member 11 is provided between the base leg 12 and the surface plate 10. The vibration absorbing member 11 absorbs the vibration of the floor surface 13 and acts so that the vibration of the floor surface 13 generated when a person walks around is not transmitted to the stage 7. On the other hand, the laser oscillator 1 is disposed independently of the structure and is fixed to the floor surface 13.

  The stage 7 is installed on the upper surface of the surface plate 10 with a linear motion member 8 interposed therebetween. The linear motion member 8 is provided so as to be movable in the left-right direction in FIG. Further, the stage 7 is provided so as to be movable in the depth direction of FIG. 1 by other linear motion members (not shown) and other linear motion guides. That is, the stage 7 is provided so as to be movable two-dimensionally. On the surface of the stage 7, a workpiece to be irradiated with the laser, that is, a laser irradiated object 6 is placed.

  The laser oscillator 1 oscillates a laser beam 20 irradiated on the laser irradiation object 6. The lens 5 is arranged in a laser path where the laser light 20 oscillated from the laser oscillator 1 reaches the laser irradiated object 6, and condenses the laser light 20 incident on the lens 5 to the laser irradiated object 6. Irradiate. The optical axis shift member 2 is disposed in the laser path between the laser oscillator 1 and the lens 5 and corrects the optical axis position of the laser light 20. The measuring instrument 3 measures the optical axis position of the laser beam 20 in the laser path between the optical axis shift member 2 and the lens 5. Here, the optical axis is a straight line formed by the locus of the center of the laser beam. The optical axis position indicates a relative optical axis position viewed from a fixed point (for example, the installation position of the measuring instrument 3) in the structure supported by the surface plate 10.

  In FIG. 1, the linear motion member 8 is in the center of the surface plate 10, and this state is set as a reference position. At this time, the center of gravity of the structure supported by the surface plate 10 is at the G0 position. The angle of the surface that reflects the laser beam 20 of the mirror 4 with respect to the surface on which the laser irradiated object 6 of the stage 7 is placed is 45 °. When the linear motion member 8 is at the reference position, the angle of the surface of the mirror 4 that reflects the laser light 20 with respect to the horizontal plane is 45 °. The laser beam 20 oscillated from the laser oscillator 1 is horizontal until it enters the mirror 4, is reflected by the mirror 4, is bent by 90 °, and enters the center of the lens 5 perpendicularly. Therefore, the mirror incident angle as the deflector incident angle (that is, the optical axis of the laser light 20 and the point at which the laser light 20 is incident on the mirror 4) is the angle at which the laser light 20 is incident on the mirror 4 as the deflector. The angle formed by the normal line of the mirror 4 is 45 °. The lens incident angle (that is, the angle formed by the optical axis of the laser light 20 and the normal of the lens 5 at the point where the laser light 20 enters the lens 5) is the angle at which the laser light 20 is incident on the lens 5. , 0 °. Then, the laser beam 20 collected by the lens 5 is irradiated onto the laser irradiated object 6 placed on the stage 7.

  FIG. 2 is a schematic diagram for correcting the optical axis position of the laser beam by the parallel plate. In FIG. 2, as in FIG. 12, the center of gravity of the structure supported by the surface plate 10 moves from the G0 position to the G2 position as the linear motion member 8 moves. Therefore, the stage 7 has an inclination angle of size θ (see FIG. 13), and the laser irradiated object 6 placed on the stage 7 is inclined. When the optical axis position of the laser beam is not corrected with the stage 7 tilted, the laser beam 21 incident on the lens 5 changes its optical axis position by δA from the center of the lens 5 as described with reference to FIG. Will do. Therefore, the laser beam 20 can be incident on the center of the lens 5 by correcting the optical axis position of the laser beam 20 using the parallel plate 2a as the optical axis shift member.

  FIG. 3 is a schematic diagram for explaining the principle of correcting the optical axis position using a parallel plate. As shown in FIG. 3, when the laser beam 20 passes through the parallel plate 2a, the laser beam 20 is refracted by the refraction of the laser beam 20, so that the laser beam 20 has an optical axis position of δB relative to the laser beam 21 when the optical axis position is not corrected. Is corrected.

Here, the refractive index n ₁ of the atmosphere, the refractive index n _{2 of} the parallel plate 2a, the angle (incident angle) ψ ₁ formed by the laser beam 20 incident on the parallel plate 2a and the normal line of the parallel plate 2a, within the parallel plate 2a Assuming that the angle (refraction angle) ψ ₂ formed by the laser beam 20 and the normal line of the parallel plate 2a is, the following relational expression is established from Snell's law.

n ₁ sinψ ₁ = n ₂ sinψ ₂
Therefore, when the thickness d of the parallel plate 2a is assumed, the optical axis position correction amount δB is expressed as a function of the incident angle ψ ₁ by the following equation (A).
δB = (d / cosφ ₂ ) · sin (φ ₁ −φ ₂ )
= D [sinψ ₁ − (n ₁ / n ₂ ) (sinψ ₁ cosψ ₁ ) / √ {1- (n ₁ sinψ ₁ / n ₂ ) ² }] (A)
As shown in FIG. 2, the correction amount δB of the optical axis position of the laser beam 20 can be measured by the measuring device 3. The measured correction amount δB is transmitted to the control unit 14 and used for controlling the parallel plate 2a. Since the incident angle ψ ₁ can be controlled by controlling the inclination of the parallel plate 2a, the correction amount δB of the optical axis position can be controlled from the equation (A).

  Then, the parallel plate is set such that the correction amount δB of the optical axis position is equal to the change amount δA of the optical axis position from the center of the lens 5 when the laser beam 21 is incident on the lens 5 when the correction is not performed. 2a is controlled. Specifically, the laser beam 20 can be controlled to enter the center of the lens 5 by controlling the parallel plate 2 a while measuring δB by the measuring instrument 3. At this time, the laser beam 20 is incident on the lens 5 with a lens incident angle having a size θ at the center of the lens 5. For example, when the stage tilt angle magnitude θ = 2 °, as shown in FIG. 2, the lens incident angle is 2 °, and the angle formed by the optical axis of the laser beam 20 and the surface of the lens 5 is 88 °. It is. However, when the lens incident angle is 0.57 ° (about 10 mrad) or less, if the laser light 20 can be controlled to be incident on the center of the lens 5, the laser light 20 with respect to the normal at the center of the lens 5. Even if it is tilted (ie, has a lens incident angle other than 0 °) and enters the lens 5, it is considered that the processing accuracy of the laser irradiated object 6 is not greatly affected. Therefore, by adjusting the parallel plate 2a so that the laser beam 20 is incident on the center of the lens 5, the characteristics of the laser beam 20 irradiated on the laser irradiation object 6 can be stabilized, and the laser irradiation can be performed. The processing accuracy of the article 6 can be stabilized.

  Since the stage 7 can be moved two-dimensionally, a change in the optical axis position from the center of the lens 5 when the laser beam 21 is incident on the lens 5 without correction is also generated two-dimensionally. To do. In other words, not only the change amount δA of the optical axis position in the horizontal direction in the drawing shown in FIG. 2, but also the change in the optical axis position occurs in the depth direction of the drawing. In order to appropriately correct such a two-dimensional change in the optical axis position, the parallel plate 2a serving as the optical axis shift member is provided around the two orthogonal axes on the plane where the laser light 20 enters the parallel plate 2a. The rotation angle can be controlled and is controlled by the control unit 14.

  FIG. 14 is a schematic diagram showing two orthogonal axes on the plane of the parallel plate 2a on which the laser beam 20 is incident. As shown in FIG. 14, the horizontal axis 30 is an intersection line between the parallel flat plate 2a and the horizontal plane, and the horizontal axis 30 is a line perpendicular to the horizontal axis 30 on the plane where the laser light 20 is incident on the parallel flat plate 2a. The axis 30 and the orthogonal axis 31 are two orthogonal axes. The parallel plate 2a can be configured such that the rotation angle of the parallel plate 2a having the horizontal axis 30 as the rotation axis and the rotation angle of the parallel plate 2a having the orthogonal axis 31 as the rotation axis can be controlled. For example, one rotating member having a cylindrical shape and rotatable about an axis is disposed along the horizontal axis 30, and the one rotating member is connected to the parallel plate 2 a, and has a cylindrical shape and has an axis about the axis. Another rotating member that can rotate can be arranged along the orthogonal axis 31, and the other rotating member can be connected to one rotating member. As a result, even when the two-dimensional optical axis position of the laser beam 20 changes due to the two-dimensional movement of the stage 7, the laser beam 20 is parallel so that the laser beam 20 enters the center of the lens 5 with higher accuracy. The flat plate 2a can be adjusted.

  In addition, a diffractive lens can be used as the lens 5. A diffractive lens is a lens that collects light by bending light using a light diffraction phenomenon. That is, by using the diffraction phenomenon of light to superimpose or cancel light waves, the direction in which the light is transmitted can be changed, and a diffractive lens uses this.

  FIG. 10 is a schematic diagram showing the configuration of a diffractive lens. 10A is a schematic sectional view of a diffractive lens, and FIG. 10B is a schematic plan view of the diffractive lens. As shown in FIG. 10A, the surface of the diffractive lens 5a is formed like a transmissive diffraction grating. Further, as shown in FIG. 10B, a concentric pattern is seen on the surface of the diffractive lens 5a. Since the diffraction lens can change the light traveling direction by changing the grating interval of the diffraction grating, the lens having the same function as the aspherical lens can be obtained by adjusting the grating interval.

  When using a diffractive lens, it is necessary to position the laser beam and the center of the lens with high accuracy in order to obtain a desired processing accuracy. In the laser irradiation apparatus according to the first embodiment, the diffractive lens 5a is used because the laser beam 20 can be adjusted to be incident on the center of the lens 5 by controlling the parallel plate 2a as the optical axis shift member. be able to. By using the diffractive lens 5a in the laser irradiation apparatus, it is possible to achieve higher processing efficiency and higher accuracy.

(Embodiment 2)
FIG. 4 is a schematic diagram showing the configuration of the laser irradiation apparatus of the second embodiment. The laser irradiation apparatus according to the second embodiment and the laser irradiation apparatus according to the first embodiment described above basically have the same configuration. However, the second embodiment is different from the first embodiment in that the optical axis shift member is configured as shown in FIG.

  Specifically, as shown in FIG. 4, the optical axis shift member 2 is composed of two prisms 2b. That is, when the laser beam 20 passes through the prism 2b, which is a transparent body having a plurality of polished surfaces formed at a predetermined angle that is not parallel, the optical axis position is corrected and the laser beam 20 reaches the mirror 4. The inclination of the two prisms 2 b is controlled by the control unit 14.

  FIG. 5 is a schematic diagram for explaining the principle of correcting the optical axis position using two prisms. As shown in FIG. 5, the two prisms 2b are arranged in parallel such that the edge on the thin side of one prism and the edge on the thick side of the other prism are close to each other. The laser beam 20 oscillated from the laser oscillator 1 is refracted when passing through the first prism. Therefore, the laser beam 20 after passing through the first prism is not parallel to the laser beam 20 before entering the first prism, and has a certain angle. Thereafter, the laser beam 20 enters the second prism and is refracted when passing through the second prism. As a result, the laser beam 20 after passing through the second prism becomes parallel to the laser beam 20 before entering the first prism. The distance δB between the laser beam 20 after passing through the second prism and the laser beam 21 when not corrected is the correction amount of the optical axis position of the laser beam 20. δB is determined by the incident angle of the laser beam 20 on the prism 2b. In other words, the correction amount δB of the optical axis position can be controlled by controlling the inclination of the two prisms 2b.

  As the two prisms 2b, prisms having the same prism refractive power are preferably used. It is more preferable if the prisms have the same material and shape. As the shape of the prism 2b, for example, a triangular prism or a wedge prism can be used.

  Similar to the parallel plate 2a as the optical axis shift member in the first embodiment, the prism 2b is configured to be able to control the rotation angle around two orthogonal axes on the surface on which the laser light 20 enters the prism 2b. If it is controlled by the control unit 14, the change in the optical axis position of the two-dimensional laser beam 20 from the center of the lens 5 can be corrected appropriately. Therefore, it can be adjusted so that the laser beam 20 is incident on the center of the lens 5 with higher accuracy.

(Embodiment 3)
FIG. 6 is a schematic diagram showing the configuration of the laser irradiation apparatus according to the third embodiment. The laser irradiation apparatus according to the third embodiment and the laser irradiation apparatus according to the first embodiment described above basically have the same configuration. However, the third embodiment is different from the first embodiment in that the mirror is configured as shown in FIG.

  Specifically, as shown in FIG. 6, the mirror 4 as a deflector is disposed in the laser path between the parallel plate 2 a as the optical axis shift member and the lens 5, and the laser light 20 is converted into the lens 5. The angle of incidence of the lens, which is the angle of incidence on the lens, is adjustable. That is, the mirror 4 of the third embodiment is provided so that the control unit 14 can control the tilt of the mirror 4. By controlling the mirror 4, in addition to correcting the change in the optical axis position of the laser light 20, the lens incident angle can be adjusted. For example, as the mirror 4, a galvanometer mirror, a piezo mirror deflector, or the like can be used.

  FIG. 7 is an enlarged schematic view showing the vicinity of the region VII in FIG. As shown in FIG. 7, the laser light 20 that has been corrected for the change in the optical axis position at the distance of δC by the parallel plate 2 a is deflected by reflection at the mirror 4. As described in the first embodiment, if the mirror 4 is fixed to the structure supported by the surface plate 10, the laser beam is used for the inclination of the stage 7 (that is, the inclination of the laser irradiated object 6). 20 is inclined with respect to the normal line at the center of the lens 5, that is, has a lens incident angle other than 0 °, and enters the lens 5. On the other hand, the mirror 4 of Embodiment 3 is provided so that the lens incident angle can be adjusted. Therefore, even when the laser irradiated object 6 is inclined, correction of the change of the optical axis position by the parallel plate 2a and adjustment of the lens incident angle by the mirror 4 (shown by the solid line from the position shown by the broken line in FIG. 7). The laser beam 20 is adjusted so as to be incident on the center of the lens 5 and along the normal line at the center of the lens 5 (that is, the incident angle of the lens is 0 °). be able to. Therefore, the characteristic of the laser beam 20 irradiated to the laser irradiated object 6 can be further stabilized, and the processing accuracy can be further stabilized.

  Further, when the laser irradiation apparatus includes a sensor capable of measuring the tilt angle, the lens incident angle can be controlled using the magnitude θ of the tilt angle measured by the sensor. Here, the tilt angle refers to the surface of the stage 7 after the movement as viewed from the surface on which the laser irradiated object 6 of the stage 7 before the movement is placed when the stage 7 is inclined as the stage 7 moves. Indicates the angle formed by. The mirror 4 serving as the deflector has a relative angle with respect to the structure supported by the surface plate 10 of the mirror 4 opposite to the direction of the inclination angle with respect to the inclination angle having the magnitude of θ measured by the sensor. If controlled by the control unit 14 so as to be inclined by θ / 2 in the direction, the laser light 20 can be adjusted to be incident along the normal line at the center of the lens 5.

  For example, as shown in FIG. 6, the angle θ of the tilt angle is 2 °, and the angle formed between the locus of the laser light 21 and the surface of the lens 5 when not corrected is 92 ° (that is, the lens incident angle is 2 °), if the mirror 4 is controlled to be tilted by −1 ° (= −2 ° / 2), the laser light 20 is aligned along the normal line at the center of the lens 5 (that is, the lens incidence). It can be adjusted to be incident (with an angle of 0 °). In FIG. 6, the clockwise direction that is the tilt direction of the stage 7 (laser irradiated object 6) is the positive direction, and the counterclockwise direction that is opposite to the tilt direction of the stage 7 is the negative (−) direction. Therefore, by controlling the mirror 4 as the deflector using the inclination angle having the magnitude of θ measured by the sensor, the laser light 20 is at the center of the lens 5 and the normal line at the center of the lens 5. It can adjust more easily so that it may inject along.

  As with the parallel plate 2a as the optical axis shift member in the first embodiment, the mirror 4 can control the rotation angle around two orthogonal axes on the surface on which the laser light 20 enters the mirror 4. If it is configured to be controlled by the control unit 14, the change in the optical axis position of the two-dimensional laser beam 20 from the center of the lens 5 can be corrected appropriately. Therefore, it can be adjusted so that the laser beam 20 is incident on the center of the lens 5 with higher accuracy.

(Embodiment 4)
FIG. 8 is a schematic diagram showing the configuration of the laser irradiation apparatus according to the fourth embodiment. The laser irradiation apparatus according to the fourth embodiment and the laser irradiation apparatus according to the second embodiment described above basically have the same configuration. However, the fourth embodiment is different from the second embodiment in that the prism 2b is configured as shown in FIG.

  Specifically, as shown in FIG. 8, the two prisms 2 b constituting the optical axis shift member 2 are provided such that their inclinations can be independently controlled by the control unit 14. By independently controlling the inclination of each of the two prisms 2b, the mirror incident angle as the deflector incident angle, which is the angle at which the laser light 20 enters the mirror 4 as the deflector, is adjusted. By adjusting the mirror incident angle, it is possible to adjust the lens incident angle, which is the angle at which the laser light 20 is incident on the lens 5. That is, by controlling the prism 2b, in addition to correcting the change in the optical axis position of the laser light 20, the lens incident angle can be adjusted.

  FIG. 9 is an enlarged schematic view showing the vicinity of the region IX in FIG. As shown in FIG. 9, since the mirror 4 is inclined with the inclination of the structure including the stage 7 supported by the surface plate 10, the laser beam 21 when the optical axis position is not corrected is When the linear motion member 8 is at the reference position, the laser beam 20 is incident on the mirror 4 at a position where the laser beam 20 is incident on the mirror 4, for example, at a point deviated from the center 4a of the mirror. On the other hand, the laser beam 20 whose optical axis position change and optical axis angle have been corrected when passing through the prism 2b is incident on the mirror 4 at the center 4a of the mirror. It can be confirmed by the measuring instrument 3 that the laser beam 20 is incident on the center 4a of the mirror.

  When the laser irradiation apparatus includes a sensor capable of measuring the tilt angle, the lens incident angle can be controlled using the tilt angle magnitude θ measured by the sensor, as in the third embodiment. If the two prisms 2b are controlled by the control unit 14 so that the mirror incident angle is inclined by θ in the same direction as the inclination angle with respect to the inclination angle having the magnitude of θ measured by the sensor. The laser beam 20 can be adjusted so as to be incident on the lens 5 along the normal line at the center of the lens 5.

  For example, as shown in FIG. 8, the angle θ of the tilt angle is 2 °, and the angle formed between the locus of the laser beam 21 and the surface of the lens 5 when not corrected is 92 ° (that is, the lens incident angle is 2 °), if the two prisms 2b are controlled so that the mirror incident angle is inclined by 2 °, the laser light 20 is aligned along the normal at the center of the lens 5 (that is, the lens incident angle is Can be adjusted to be incident). In FIG. 8, the tilt angle in the clockwise direction, which is the tilt direction of the stage 7 (laser irradiated object 6), is defined as the positive direction. Therefore, by controlling the two prisms 2b as the optical axis shift member using the inclination angle having the magnitude of θ measured by the sensor, the laser light 20 is at the center of the lens 5 and the lens 5 It can be adjusted more easily so that it is incident along the normal line at the center.

  In the description of the first to fourth embodiments, an example in which the laser beam 20 is reflected by the mirror 4 serving as a deflector and is bent by approximately 90 ° is described. For example, a prism that can bend light at a right angle, such as a prism or a miss prism, can be used. Further, if the laser oscillator 1 can be disposed on the laser irradiation object by installing it on a structure including a stage, for example, a deflector for bending the laser light at a right angle can be eliminated. However, since it is extremely difficult to dispose a large laser oscillator in the structure, when using a large laser oscillator, the laser oscillator described in the above embodiment is fixed to the floor surface, and laser light is emitted. It is advantageous to have a structure that bends at right angles by a deflector such as a mirror 4.

  The embodiment disclosed this time is to be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The laser irradiation apparatus of the present invention can be particularly advantageously applied to a large-sized laser irradiation apparatus for the purpose of performing highly accurate and highly efficient processing.

It is a schematic diagram which shows the structure of the laser irradiation apparatus of Embodiment 1 of this invention. It is a schematic diagram which correct | amends the optical-axis position of a laser beam with a parallel plate. It is a schematic diagram explaining the principle which correct | amends an optical axis position using a parallel plate. 6 is a schematic diagram illustrating a configuration of a laser irradiation apparatus according to a second embodiment. FIG. It is a schematic diagram explaining the principle which correct | amends an optical axis position using two prisms. FIG. 6 is a schematic diagram illustrating a configuration of a laser irradiation apparatus according to a third embodiment. It is a schematic diagram which expands and shows the area | region VII vicinity of FIG. FIG. 6 is a schematic diagram illustrating a configuration of a laser irradiation apparatus according to a fourth embodiment. It is a schematic diagram which expands and shows the area | region IX vicinity of FIG. It is a schematic diagram which shows the structure of a diffraction type lens. It is a schematic diagram which shows the structure of the conventional laser irradiation apparatus. It is a schematic diagram which shows the state in which the stage inclined. It is a schematic diagram explaining the inclination-angle of a stage. It is a schematic diagram which shows two orthogonal axes | shafts in the surface into which the laser beam of a parallel plate enters.

Explanation of symbols

  1 laser oscillator, 2 optical axis shift member, 2a parallel plate, 2b prism, 3 measuring instrument, 4 mirror, 4a center of mirror, 5 lens, 5a diffractive lens, 6 laser irradiated object, 7 stage, 8 linear motion Member, 9 linear motion guide, 10 surface plate, 11 vibration absorbing member, 12 base leg, 13 floor surface, 14 control unit, 20 laser beam, 21 laser beam when optical axis position is not corrected, 30 horizontal axis, 31 orthogonal axis.

Claims (7)

A stage on which a laser irradiation object is placed and movable in two dimensions;
A laser oscillator that is arranged independently of the stage, and that oscillates a laser beam irradiated to the laser irradiation object;
The laser beam oscillated from the laser oscillator is disposed in a laser path leading to the laser irradiation object, and a lens that focuses the laser beam;
An optical axis shift member that is disposed in the laser path between the laser oscillator and the lens and corrects the optical axis position of the laser beam;
A measuring instrument for measuring the optical axis position in the laser path between the optical axis shift member and the lens;
A control unit that controls the optical axis shift member in accordance with the optical axis position measured by the measuring instrument so as to cancel the change in the optical axis position of the laser beam that occurs as the stage moves. Laser irradiation device.   2. The apparatus according to claim 1, further comprising a deflector that is disposed in the laser path between the optical axis shift member and the lens and adjusts a lens incident angle that is an angle at which the laser light is incident on the lens. Laser irradiation device. When the stage is tilted as the stage is moved, an inclination angle formed by the surface of the stage after the movement as viewed from the surface on which the laser irradiated object of the stage before the movement is placed is formed. Equipped with measurable sensors,
3. The control unit according to claim 2, wherein the control unit controls the deflector to tilt θ / 2 in a direction opposite to the tilt angle with respect to the tilt angle having a magnitude of θ measured by the sensor. Laser irradiation device. The optical axis shift member is provided such that a deflector incident angle, which is an angle at which the laser light is incident on the deflector, can be adjusted.
When the stage is tilted as the stage is moved, an inclination angle formed by the surface of the stage after the movement as viewed from the surface on which the laser irradiated object of the stage before the movement is placed is formed. Equipped with measurable sensors,
The control unit controls the optical axis shift member so that the incident angle of the deflector is inclined by θ in the same direction as the inclination angle with respect to the inclination angle having a magnitude of θ measured by the sensor. The laser irradiation apparatus according to claim 1. The optical axis shift member is a parallel plate,
The laser irradiation according to any one of claims 1 to 4, wherein the control unit controls a rotation angle around two orthogonal axes on a plane of the parallel plate on which the laser light is incident on the parallel plate. apparatus. The optical axis shift member is composed of two or more prisms,
5. The laser irradiation apparatus according to claim 1, wherein the control unit controls a rotation angle around two orthogonal axes on a surface of the prism on which the laser light is incident on the prism. 6.   The laser irradiation apparatus according to claim 1, wherein the lens is a diffractive lens.

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