JP5364279B2 - Laser irradiation apparatus, focus control method and tilt control method of laser irradiation apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser irradiation device etc., whose optical head unit is made lightweight. <P>SOLUTION: The laser irradiation device makes laser beams emitted by a plurality of laser light emission units incident on a light guide plate 13 through an optical fiber 2 to irradiate an irradiation object with a laser spot formed by converging a laser beam projected from the light guide plate 13 through an objective 16. The reflected laser beam reflected by the irradiation object is received by the light guide plate 13, the received reflected laser beam is guided to an AF optical system 30 from a return light fiber 5 connected to an end surface of the light guide plate 13, and the AF optical system 30 performs automatic focusing control using the reflected laser beam. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a laser irradiation apparatus that irradiates a laser beam while performing focus control on an irradiation object, and a focus control method and a tilt control method of the laser irradiation apparatus, and can perform particularly stable focus control and tilt control. The present invention relates to a laser irradiation apparatus and a focus control method and a tilt control method of the laser irradiation apparatus.

  Generally, a laser irradiation apparatus is used in a laser annealing apparatus or the like that changes a physical characteristic of an irradiation object by irradiating a laser spot focused on the irradiation object.

  As shown in FIG. 6, a laser irradiation apparatus that performs laser spot focus control according to the prior art includes a plurality of semiconductor laser elements 1a to 1n that emit laser beams and laser beams emitted from the plurality of semiconductor laser elements 1a to 1n. A plurality of optical fibers 2 that enter the beam at one end, and a light guide plate 13 that allows a plurality of laser beams emitted from the other end of the plurality of optical fibers to enter from one end side surface and emits from the other end side surface while irregularly reflecting inside. The collimating lens 14 that converts the laser beam emitted from the light guide plate 13 into parallel light, and the objective lens 16 that condenses the laser beam that is parallel light emitted from the collimating lens 14 and irradiates the irradiation object 20. And PBS (polarizing beam splitter: polarizing incident light) that polarizes the traveling direction of the reflected light from the irradiation object 20 by 45 degrees. A filter 15 that separates the polarized light components), an AF (autofocus) condensing lens 12 that condenses the laser beam polarized by the PBS 15 as return light 17, and a detector 11 that receives the collected return light 17. And an autofocus (AF) control unit (not shown) that performs focusing on the irradiation object 20 by the astigmatism method based on the return light 17 received by the detector 11.

  The astigmatism method described above is a method for measuring the displacement in the optical axis direction in a non-contact manner by detecting distortion of a point image formed by an optical system having astigmatism, and the focal length of the lens. Using astigmatism due to different values in two orthogonal cross-sections including the optical axis, and combining point images in an optical system with this astigmatism, the image is vertically long, circular, This is a technique for measuring the displacement in the optical axis direction by detecting the change using a four-divided photodetector.

  The laser irradiation apparatus configured in this manner polarizes the laser beam reflected from the irradiation object 20 by the PBS 15 and stops it by the AF condensing lens 12, which is received by the detector 11, and receives a control signal from the autofocus control unit. By moving the objective lens 16 with respect to the irradiation object 20 based on the above, the laser spot on the irradiation object 20 is controlled to be focused.

Incidentally, as a document describing the technology related to the laser annealing apparatus described above, the following patent document can be cited. Patent Document 1 discloses a technique for crystallizing a semiconductor film by irradiating a laser to an amorphous semiconductor film. In Patent Document 2, a laser beam emitted from a plurality of semiconductor laser elements is joined to one end of a plate-like optical waveguide via an optical fiber, and a laser beam emitted from the other end of the optical waveguide is A technique for irradiating an irradiation target with a laser spot focused by a focusing lens is described.
JP 2004-241421 A JP 2007-115729 A

  In the laser irradiation apparatus according to the above-described prior art, the focus control optical system must be provided with a focus control optical path different from the linear main optical system from the semiconductor laser elements 1a to 1n as the light source to the irradiation target 20. In addition, the overall structure of the optical head unit 10 including the light guide plate 13 / collimator lens 14 / objective lens 16 / AF condenser lens 12 / detector 11 and the drive unit of the objective lens 16 is complicated, and the mounting volume and weight are also increased. There was a problem of getting bigger.

  In addition, there is a problem that the focus control may become unstable due to vibration due to movement of the optical head unit 10 due to the increase in weight. In particular, in a laser irradiation apparatus used for annealing (crystallization) of a large liquid crystal panel, the influence is large, and the weight reduction of the optical head part has been a big problem.

  Further, in order to irradiate a laser spot with a predetermined intensity distribution onto a minute portion, a laser irradiation apparatus needs to irradiate a laser spot perpendicularly to an irradiation target. There was a problem that the optical axis adjustment of the head part was not taken into consideration.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a laser irradiation apparatus capable of stabilizing the focus control by reducing the weight of the optical head unit and easily adjusting the optical axis, and a focus control method and a tilt control method of the laser irradiation apparatus. is there.

In order to achieve the above object, the present invention is a laser irradiation apparatus for condensing laser beams emitted from a plurality of laser light emitting units and irradiating the focused laser spots while focusing on an irradiation object,
A plurality of irradiation light fibers incident on one end of the laser beams emitted from the plurality of laser light emitting units, and a plurality of laser beams emitted from the other end of the plurality of optical fibers are incident from one end side surface and diffusely reflected inside. An elongated light guide plate that is emitted from the side surface of the other end, a collimator lens that converts the laser beam emitted from the light guide plate into parallel light, and the parallel laser beam emitted from the collimator lens is condensed to be irradiated. An objective lens that irradiates the light beam, a return light fiber that guides the reflected laser beam reflected from the irradiation object and incident on the light guide plate to the outside from one side surface of the light guide plate, and emitted from the other end of the return light fiber And a circuit unit for receiving the reflected laser beam.

Furthermore, the present invention is a laser irradiation apparatus for condensing laser beams emitted from a plurality of laser light emitting units and irradiating the focused laser spots while focusing on an irradiation object,
A plurality of irradiation light fibers incident on one end of the laser beams emitted from the plurality of laser light emitting units, and a plurality of laser beams emitted from the other end of the plurality of optical fibers are incident from one end side surface and diffusely reflected inside. An elongated light guide plate that is emitted from the side surface of the other end, a collimator lens that converts the laser beam emitted from the light guide plate into parallel light, and the parallel laser beam emitted from the collimator lens is condensed to be irradiated. An objective lens that irradiates the light beam, a return light fiber that guides the reflected laser beam reflected from the irradiation object and incident on the light guide plate to the outside from one side surface of the light guide plate, and emitted from the other end of the return light fiber A second feature is that an AF control unit that controls the focusing of the irradiated laser beam on the object to be irradiated is provided.

  According to the present invention, in the laser irradiation apparatus of the second feature, the AF control unit is configured so that the peak of the reflected laser beam light amount reflected from the irradiation object and incident through the light guide plate is near the maximum value. A third feature is that the focusing control is performed by adjusting the distance of the lens to the irradiation object.

  According to the present invention, in the laser irradiation apparatus of the second or third feature, at least one pair of the irradiation light fibers is arranged near the left and right ends of one end side surface of the long plate-shaped light guide plate, and the return light fibers Is arranged on one end side surface of the light guide plate between the pair of fibers for irradiation light.

  According to the fifth aspect of the present invention, in the laser irradiation apparatus according to any one of the fourth characteristics, the return light fiber is disposed in the vicinity of the center in the length direction of one side surface of the light guide plate. And

Further, in the present invention, a plurality of irradiation light fibers incident on one end of laser beams emitted from a plurality of laser light emitting units, and a plurality of laser beams emitted from the other end of the plurality of optical fibers are incident from one end side surface. A long plate-shaped light guide plate that emits from the other side surface while being irregularly reflected inside, a collimator lens that converts the laser beam emitted from the light guide plate into parallel light, and the parallel laser beam emitted from the collimator lens is condensed. A focus control method of a laser irradiation apparatus that irradiates an irradiation target while focusing a laser spot on which the laser beams emitted from the plurality of laser light emitting portions are focused. There,
A return light fiber that guides the reflected laser beam reflected from the irradiation object and incident on the light guide plate to the outside from one side surface of the light guide plate, and a laser beam emitted from the other end of the return light fiber are incident. And an AF control unit for controlling the focusing on the irradiation object of the laser beam,
A sixth feature is that the AF control unit performs focusing control using a reflected laser beam reflected from an irradiation object and incident through the light guide plate.

  According to the present invention, in the focus control method of the above feature, the objective lens is irradiated so that the peak of the reflected laser beam light amount reflected by the AF control unit and incident through the light guide plate is near the maximum value. The seventh feature is that the focusing control is performed by adjusting the distance to the object.

  In the focus control method according to the seventh aspect of the present invention, at least a pair of the irradiation light fibers is arranged near the left and right ends of one side surface of the long plate-shaped light guide plate, and the return light fibers are Irradiation is performed using a reflected laser beam emitted from a return light fiber disposed between one pair of irradiation light fibers on one side surface of the light guide plate between the pair of irradiation light fibers. The eighth feature is that the focusing control for the irradiation target of the laser spot is performed.

  According to the present invention, in the focus control method according to the eighth feature, the return light fiber is disposed in the vicinity of the center in the length direction of one side surface of the light guide plate, and is disposed in the vicinity of the center. A ninth feature is that focusing control of an irradiation laser spot with respect to an irradiation object is performed using a reflected laser beam emitted from the laser beam.

Furthermore, the present invention is a laser irradiation apparatus for condensing laser beams emitted from a plurality of laser light emitting sections and irradiating the focused laser spots while focusing on an irradiation object, wherein the plurality of laser light emission units A plurality of irradiation light fibers incident on one end of the laser beam emitted from the part, and a plurality of laser beams emitted from the other end of the plurality of optical fibers are incident from one side surface, and diffusely reflected from the other side surface A pair of long plate-shaped light guide plates to be emitted, a collimator lens for converting the laser beam emitted from the pair of light guide plates into parallel light, and the parallel laser beam emitted from the collimator lens is condensed to be irradiated. an objective lens for irradiating the reflected laser beam respectively incident to the outside from one end side of the light guide plate to the light guide plate of the pair of light guide plates is reflected from the irradiated object Tilt control that adjusts the optical axis of a laser spot using a plurality of reflected laser beams incident on the plurality of return light fibers and a plurality of reflected laser beams emitted from the other ends of the plurality of return light fibers. A tenth feature.

  According to the present invention, in the laser irradiation apparatus having the tenth feature, the pair of light guide plates are arranged symmetrically with respect to the optical axis of the laser spot, and the irradiation light fiber is disposed at one end side of the long plate light guide plate. At least one pair in the vicinity of the left and right ends of the light source, the return light fibers are disposed on one end side surface of the light guide plate between the pair of irradiation light fibers, and the tilt control unit is disposed on the one side surface of the light guide plate. An eleventh feature is that the optical axis of the laser spot is adjusted using a reflected laser beam emitted from a return light fiber disposed between the optical fibers.

  Further, the present invention provides the laser irradiation apparatus according to claim 10, wherein the return light fiber is disposed in the vicinity of the center in the length direction of one side surface of the light guide plate, and the tilt control unit is disposed in the vicinity of the center. The twelfth feature is that the optical axis of the irradiated laser spot is adjusted using the reflected laser beam emitted from the arranged return light fiber.

Further, in the present invention, a plurality of irradiation light fibers incident on one end of laser beams emitted from a plurality of laser light emitting units, and a plurality of laser beams emitted from the other end of the plurality of optical fibers are incident from one end side surface. A pair of long light guide plates that are emitted from the side surface of the other end while being irregularly reflected inside, a collimator lens that converts a laser beam emitted from the pair of light guide plates into parallel light, and a parallel laser beam emitted from the collimator lens And a plurality of return lights for guiding a reflected laser beam reflected from the irradiation object and incident on the pair of light guide plates to the outside from one side surface of the light guide plate. A plurality of reflected laser beams emitted from the other end of the fiber and the plurality of return light fibers are incident, and an optical axis of a laser spot using the plurality of reflected laser beams A tilt control method of the laser irradiation apparatus and a tilt control unit for performing integer, the tilt control unit is reflected from the irradiated object, using a plurality of reflected laser beam incident through the light guide plates The thirteenth feature is that the optical axis of the laser spot is adjusted.

  In the tilt control method of the thirteenth feature, according to the fourteenth feature, the tilt control unit adjusts the optical axis so that the maximum amounts of received light of the plurality of reflected laser beams emitted from the plurality of light guide plates match. To do.

  In the tilt control method according to the thirteenth or fourteenth aspect of the present invention, the pair of light guide plates are arranged symmetrically with respect to the optical axis of the laser spot, and the irradiation light fiber is arranged at one end of the long plate-shaped light guide plate. A pair of at least one pair is disposed near the left and right ends of the side surface, the return light fiber is disposed on one end side surface of the light guide plate between the pair of irradiation light fibers, and the tilt control unit is a pair of one side surface of the light guide plate. A fifteenth feature is that the optical axis of the laser spot is adjusted using a reflected laser beam emitted from a return light fiber disposed between the irradiation light fibers.

  In the tilt control method according to the thirteenth or fourteenth aspect of the present invention, the return light fiber is disposed in the vicinity of the center in the length direction of one side surface of the light guide plate, and the tilt control unit includes the center. A sixteenth feature is that focusing control of an irradiation laser spot with respect to an irradiation object is performed using a reflected laser beam emitted from a return light fiber disposed in the vicinity.

  A laser irradiation apparatus employing the laser irradiation method and the tilt method according to the present invention receives a reflected laser spot from an irradiation object by a light guide plate, and performs focusing control or tilt control using the received reflected laser spot. As a result, the weight of the optical head can be reduced, the focus control can be stabilized, and the optical axis can be easily adjusted.

Hereinafter, an embodiment of a laser irradiation apparatus employing a laser irradiation method and a tilt method according to the present invention will be described in detail with reference to the drawings. 1 is a diagram showing a schematic configuration of a laser irradiation apparatus according to the present embodiment, FIG. 2 is a diagram for explaining a focus control signal according to the present embodiment, and FIG. 3 is a schematic configuration of a laser irradiation apparatus according to another embodiment of the present invention. FIG. 4 is a diagram illustrating a tilt control signal according to another embodiment, and FIG. 5 is a diagram illustrating transition of the tilt control signal according to another embodiment.
[First Embodiment]
As shown in FIG. 1, the laser irradiation apparatus according to the first embodiment of the present invention includes a plurality of laser light emitting sections 6a each composed of a plurality of semiconductor laser elements 1a / 1b that emit laser beams and coupling lenses 4a / 4b, and 6b, a plurality of optical fibers 2 incident on one end of the laser beams emitted from the laser light emitting sections 6a and 6b, and a plurality of laser beams emitted from the other end of the plurality of optical fibers 2 are incident from one side surface, A light guide plate 13 that is emitted from the other end while being irregularly reflected inside, a collimator lens 14 that converts the laser beam emitted from the light guide plate 13 into parallel light, and a laser beam that is parallel light emitted from the collimator lens 14. The objective lens 16 that condenses and irradiates the irradiation target 20 and the laser beam reflected from the irradiation target 20 and incident on the light guide plate 13 are guided. A return light fiber 5 guided from the center of one end side surface of the plate 13 to the outside, a condensing lens for entering and condensing a laser beam emitted from the other end of the return light fiber 5, and the condensed laser beam And an AF optical system 30 composed of a detector that outputs a signal MONC (central monitor signal) whose value changes according to the amount of received light, and a drive unit (not shown) based on a control signal from the AF optical system 30 ) And an AF control unit 35 that performs automatic focusing by driving the objective lens 16.

  The light guide plate 13 has a flat plate shape, and has a characteristic of emitting a uniform laser beam by combining a plurality of laser beams from the other side surface by internally reflecting and combining the laser beams incident from one side surface. At the same time, the laser beam incident on the side surface of the other end also has a characteristic of emitting a uniform laser beam synthesized by irregular reflection inside. In addition, the side surface to which the optical fiber of the light guide plate in the present invention is attached also constitutes a reflective surface except for the optical fiber attachment position.

  As shown in FIG. 3, the signal MONC output from the detector has a maximum output when the focus of the laser spot 7 coincides with the irradiation object 20, and is used as a focus control signal. No. 35 performs automatic focusing by driving the objective lens 16 so that the value of the signal MONC from the detector exceeds the threshold value VC. More specifically, the laser irradiation apparatus according to the present example irradiates the laser spot 7 by moving the objective lens 16 up and down in the vertical direction with respect to the surface of the irradiation object 20, and sets the output level of the signal MONC. After monitoring and determining the threshold value VC using 90% of the maximum value of the output level as a focus area, the objective lens 16 is then moved up and down, and the objective lens is moved at the moment when the value of the threshold value C is exceeded during this movement. By stopping, detecting the position of the irradiation object, and repeating this operation in a short time, the position of the irradiation object is continuously detected.

  In the laser irradiation apparatus configured as described above, the AF optical system 30 receives the laser beam reflected from the irradiation object 20 from the light guide plate 13 through the return light fiber 5, and the AF optical system 30 receives the received laser. By outputting a signal MONC whose output value changes according to the amount of light of the beam, the AF control unit 35 to which the signal MONC is input controls the position of the objective lens 16 so that the value of the signal MONC exceeds the threshold value VC. The laser spot 7 operates so as to focus on the surface of the irradiation target 20. That is, in the present embodiment, using the characteristic that the light amount of the laser beam reflected from the irradiation object 20 is maximized at the time of focusing, the objective lens is moved to a position where the light amount of the reflected laser beam is maximized. Perform focus control.

  In particular, in the laser irradiation apparatus according to the present embodiment, a plurality of laser beams from a laser beam emission source are incident from positions near both ends of one side surface of the flat plate-shaped light guide plate 13, and the reflected laser beam from the irradiation object 20 is guided. Input from the other side surface of the optical plate 13 is received by the return light fiber 5 disposed at a substantially central position on the one side surface of the light guide plate 13, and a laser beam output (returned) from the substantially central position of the light guide plate 13 is received. Since the focus control is performed based on the configuration, it is not necessary to provide a focus control optical path different from that of the main optical system as in the prior art, and the structure of the optical head unit can be simply configured.

  Furthermore, according to the present embodiment, the optical head unit 70 is configured only by the light guide plate 13, the collimator lens 14, the objective lens 16, and the objective lens 16 drive system (not shown), thereby reducing the size and weight of the optical head unit 70. In addition, the weight reduction can prevent instability of focus control due to vibration.

  In addition, according to the said embodiment, although the example which has arrange | positioned the return light fiber 5 in the center of the end side surface length direction of the light-guide plate 13 was demonstrated, the light quantity returned to the one end side surface of the light-guide plate 13 is light guide plate 13 inside. Therefore, the arrangement position is not limited to the center.

Further, according to the embodiment, the example in which the in-focus control for adjusting the objective lens position so that the light amount of the reflected laser beam becomes the maximum value has been described, but the present invention is not limited to this, and the AF is not limited thereto. The optical system 30 may output a focus error signal by the astigmatism method, and the AF control unit 35 may perform focusing control based on the focus error signal.
[Second Embodiment]
The laser irradiation apparatus according to the embodiment has been described as an example in which only the laser spot focusing control is performed. However, the laser irradiation apparatus according to the present invention can also adjust the tilt (optical axis) of the optical head unit. A form is demonstrated with reference to FIGS.

  As shown in FIG. 3, the laser irradiation apparatus according to the second embodiment of the present invention includes a plurality of laser light emitting units 6a and 6d, and a plurality of lights incident on one end of laser beams emitted from the laser light emitting units 6a and 6b. A fiber 2a, a plurality of optical fibers 2b that enter one end of the laser beam emitted from the laser emitting units 6c and 6d, and a plurality of laser beams that exit from the other end of the optical fiber 2a are incident from one side surface, A light guide plate 13a that is emitted from the other end while being irregularly reflected, and a plurality of laser beams that are emitted from the other end of the optical fiber 2, and a light guide plate 13b that is emitted from the other end while being irregularly reflected inside, A collimating lens 14 that converts the laser beams emitted from the light guide plates 13a and 13b into parallel light, and a light emitted from the collimating lens 14. The objective lens 16 that condenses the irradiated laser beam and irradiates the irradiation target 20, and the laser beam reflected from the irradiation target 20 and incident on the light guide plate 13 a is guided from the center of one end side surface of the light guide plate 13 a to the outside. A return light fiber 5a, a return light fiber 5b for guiding the laser beam reflected from the irradiation object 20 and incident on the light guide plate 13b to the outside from the center of one end side surface of the light guide plate 13b, and the return light fiber 5a An AF optical system L31 composed of a detector that receives a laser beam emitted from the other end of the laser beam and outputs a signal MONC, and a laser beam emitted from the other end of the return light fiber 5b are incident to output a signal MONC. And an optical system R32 composed of a detector for detecting the optical head and a drive unit (not shown) based on the control signals of both the AF optical systems 31 and 32. Comprising a tilt control unit 36 which controls the winding direction Z, and AF control unit 35 for performing focus control by using a drive unit (not shown) on the basis of the two AF optical system 31 and 32 control signals. In this embodiment, an example in which a pair of return light fibers that guide the reflected laser beam returned to the light guide plate to the outside is described, but the present invention is not limited to this, and the number may be an even multiple.

  When the two light guide plates 13a and 13b have the same flat plate shape and assume an optical axis that is a line segment perpendicular to the surface of the irradiation target 20 of the laser spot 7 irradiated from the objective lens 16, It arrange | positions axisymmetrically with respect to this optical axis, By this arrangement | positioning, it has the characteristic that the reflected laser beam of the same light quantity reflected from the irradiation target object 20 is reflected and input into the light-guide plates 13a and 13b.

  The laser irradiation apparatus configured in this manner returns the laser beam reflected from the irradiation target 20 from the light guide plates 13a and b through the optical fibers 5a and 5b, and the AF optical system L31 and the AF optical when the optical axis is adjusted. When each of the systems R32 receives light and the optical head unit 80 is slightly rotated in the tilt direction Z with respect to the irradiation target 20 by a driving unit (not shown), the left and right signals MONL and MONR are obtained as shown in FIG. The output signal is rotated so that the peaks of the signal MONL and the signal MONR coincide with each other, the maximum value of the sum signal is searched, the signal level of 90% is determined as Vt, and then the combined signal level is Vt By stopping the rotation when reaching the value, the inclination of the optical head unit with respect to the irradiation object 20 can be adjusted vertically. Note that the focusing control of the laser spot is controlled so that the amount of the laser beam received by the AF optical systems 31 and 32 is close to the maximum value by the AF control unit 35 as in the above-described embodiment.

  That is, according to the present embodiment, tilt control can be performed by rotating and positioning the optical head unit 80 so that the sum signal of the signal MONR shown in FIG.

  In the above embodiment, the example in which the reflected laser beam reflected from the irradiation object is received by the light guide plate and the focusing control and the optical axis adjustment are performed using the return reflected laser beam from the light guide plate has been described. However, the present invention is not limited to this, and the return reflection laser beam from the light guide plate can be used for other applications.

The figure which shows schematic structure of the laser irradiation apparatus by one Embodiment of this invention. The figure for demonstrating the focus control signal by this embodiment. The figure which shows schematic structure of the laser irradiation apparatus by other embodiment of this invention. The figure which shows the control signal for tilting by other embodiment of this invention. The figure which shows the control signal for tilting by other embodiment. The figure which shows schematic structure of the laser irradiation apparatus by a prior art.

Explanation of symbols

  1a to 1n: Semiconductor laser device, 2: Optical fiber, 2a and 2b: Optical fiber, 4a / 4b: Coupling lens, 5: Return optical fiber, 5a and 5b: Return optical fiber, 6a-6c: Laser emission part, 7: Laser spot, 10: Optical head, 11: Detector, 12: AF condenser lens, 13: Light guide plate, 13a and 13b: Light guide plate, 14: Collimator lens, 16: Objective lens, 17: Return light, 20 : Irradiation object, 30 to 31: optical system, 35: AF control unit, 36: tilt control unit, 70 to 80: optical head unit.

Claims (16)

A laser irradiation apparatus that condenses laser beams emitted from a plurality of laser light emitting units and irradiates the focused laser spots while focusing on an irradiation object,
A plurality of irradiation light fibers incident on one end of the laser beams emitted from the plurality of laser light emitting units, and a plurality of laser beams emitted from the other end of the plurality of optical fibers are incident from one end side surface and diffusely reflected inside. An elongated light guide plate that is emitted from the side surface of the other end, a collimator lens that converts the laser beam emitted from the light guide plate into parallel light, and the parallel laser beam emitted from the collimator lens is condensed to be irradiated. An objective lens that irradiates the light beam, a return light fiber that guides the reflected laser beam reflected from the irradiation object and incident on the light guide plate to the outside from one side surface of the light guide plate, and emitted from the other end of the return light fiber And a circuit unit for receiving the reflected laser beam. A laser irradiation apparatus that condenses laser beams emitted from a plurality of laser light emitting units and irradiates the focused laser spots while focusing on an irradiation object,
A plurality of irradiation light fibers incident on one end of the laser beams emitted from the plurality of laser light emitting units, and a plurality of laser beams emitted from the other end of the plurality of optical fibers are incident from one end side surface and diffusely reflected inside. An elongated light guide plate that is emitted from the side surface of the other end, a collimator lens that converts the laser beam emitted from the light guide plate into parallel light, and the parallel laser beam emitted from the collimator lens is condensed to be irradiated. An objective lens that irradiates the light beam, a return light fiber that guides the reflected laser beam reflected from the irradiation object and incident on the light guide plate to the outside from one side surface of the light guide plate, and emitted from the other end of the return light fiber Irradiation apparatus including an AF control unit that controls the focusing of a laser beam to be irradiated with a reflected laser beam incident thereon.   The AF control unit performs focusing control by adjusting the distance of the objective lens with respect to the irradiation target so that the peak of the amount of reflected laser beam reflected from the irradiation target and incident through the light guide plate is close to the maximum value. The laser irradiation apparatus of Claim 2 to perform.   At least one pair of the irradiation light fibers is disposed near the left and right ends of one end side surface of the long plate-shaped light guide plate, and the return light fibers are disposed on one end side surface of the light guide plate between the pair of irradiation light fibers. The laser irradiation apparatus according to claim 2 or 3.   The laser irradiation apparatus according to claim 4, wherein the return light fiber is disposed in the vicinity of the center in the length direction of one end side surface of the light guide plate. While irradiating a plurality of laser beams emitted from a plurality of laser light emitting sections to one end, and a plurality of laser beams emitted from the other end of the plurality of optical fibers from one side, An elongated light guide plate that is emitted from the side surface of the other end, a collimator lens that converts the laser beam emitted from the light guide plate into parallel light, and the parallel laser beam emitted from the collimator lens is condensed to be irradiated. A focus control method of a laser irradiation apparatus that irradiates an object to be irradiated while focusing a laser spot, which is provided with an irradiation objective lens, and focuses a laser spot emitted from the plurality of laser light emitting units.
A return light fiber that guides the reflected laser beam reflected from the irradiation object and incident on the light guide plate to the outside from one side surface of the light guide plate, and a laser beam emitted from the other end of the return light fiber are incident. And an AF control unit for controlling the focusing on the irradiation object of the laser beam,
A focus control method in which the AF control unit performs focusing control using a reflected laser beam reflected from an irradiation object and incident through the light guide plate.   The AF control unit performs focusing control by adjusting the distance of the objective lens with respect to the irradiation target so that the peak of the amount of reflected laser beam reflected from the irradiation target and incident through the light guide plate is close to the maximum value. The focus control method according to claim 6 to be performed.   At least one pair of the irradiation light fibers is disposed near the left and right ends of one end side surface of the long plate-shaped light guide plate, and the return light fibers are disposed on one end side surface of the light guide plate between the pair of irradiation light fibers. The focusing control of the irradiation laser spot with respect to the irradiation object is performed using a reflected laser beam emitted from a return light fiber disposed between a pair of irradiation light fibers on one side surface of the light guide plate. Focus control method.   The return light fiber is disposed in the vicinity of the center in the length direction of the one side surface of the light guide plate, and the irradiation target of the irradiation laser spot using the reflected laser beam emitted from the return light fiber disposed in the vicinity of the center The focus control method according to claim 7, wherein focus control for an object is performed. A laser irradiation apparatus that condenses laser beams emitted from a plurality of laser light emitting units and irradiates the focused laser spots while focusing on an irradiation object,
A plurality of irradiation light fibers incident on one end of the laser beams emitted from the plurality of laser light emitting units, and a plurality of laser beams emitted from the other end of the plurality of optical fibers are incident from one end side surface and diffusely reflected inside. A pair of long light guide plates that exit from the other end side surface, a collimator lens that converts the laser beams emitted from the pair of light guide plates into parallel light, and the parallel laser beams emitted from the collimator lenses are condensed. An objective lens that irradiates the object to be irradiated, and a plurality of return light fibers that guide the reflected laser beam reflected from the object to be irradiated and incident on the light guide plates of the pair of light guide plates to the outside from one side surface of the light guide plate And a plurality of reflected laser beams emitted from the other ends of the plurality of return light fibers are incident, and an optical axis adjustment of a laser spot is performed using the plurality of reflected laser beams. The laser irradiation apparatus and a tilt control unit for.   The pair of light guide plates are arranged symmetrically with respect to the optical axis of the laser spot, the irradiation light fibers are arranged at least in the vicinity of the left and right ends of one end side surface of the long plate-shaped light guide plate, and the return light fibers Is disposed on one side surface of the light guide plate between the pair of irradiation light fibers, and the tilt control unit is emitted from a return light fiber disposed between the pair of irradiation light fibers on one side surface of the light guide plate. The laser irradiation apparatus according to claim 10, wherein the optical axis of the laser spot is adjusted using a reflected laser beam.   The return light fiber is arranged in the vicinity of the center in the length direction of one side surface of the light guide plate, and the tilt control unit uses a reflected laser beam emitted from the return light fiber arranged in the vicinity of the center. The laser irradiation apparatus of Claim 10 which adjusts the optical axis of an irradiation laser spot. While irradiating a plurality of laser beams emitted from a plurality of laser light emitting sections to one end, and a plurality of laser beams emitted from the other end of the plurality of optical fibers from one side, A pair of light guide plates having a long plate shape emitted from the side surface of the other end, a collimator lens that converts the laser beam emitted from the pair of light guide plates into parallel light, and the parallel laser beam emitted from the collimator lens is condensed. An objective lens that irradiates the irradiation object; a plurality of return light fibers that guide the reflected laser beams reflected from the irradiation object and incident on the pair of light guide plates to the outside from one side surface of the light guide plate; A plurality of reflected laser beams emitted from the other end of the return light fiber and adjusting the optical axis of the laser spot using the reflected laser beams. A tilt control method of the laser irradiation apparatus and a control unit,
A tilt control method in which the tilt control unit adjusts the optical axis of a laser spot using a plurality of reflected laser beams reflected from the irradiation object and incident through the pair of light guide plates .   The tilt control method according to claim 13, wherein the tilt control unit adjusts the optical axis so that the maximum received light amounts of the plurality of reflected laser beams emitted from the plurality of light guide plates coincide.   The pair of light guide plates are arranged symmetrically with respect to the optical axis of the laser spot, the irradiation light fibers are arranged at least in the vicinity of the left and right ends of one end side surface of the long plate-shaped light guide plate, and the return light fibers Is disposed on one side surface of the light guide plate between the pair of irradiation light fibers, and the tilt control unit emits light from the return light fiber disposed between the pair of irradiation light fibers on the one side surface of the light guide plate. 15. The tilt control method according to claim 13, wherein the optical axis of the laser spot is adjusted using the reflected laser beam.   The return light fiber is arranged in the vicinity of the center in the length direction of one side surface of the light guide plate, and the tilt control unit uses a reflected laser beam emitted from the return light fiber arranged in the vicinity of the center. The tilt control method according to claim 13 or 14, wherein focus control is performed on an irradiation object of an irradiation laser spot.

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