Patent Publication Number: US-2023133411-A1

Title: Detection device, correction device, processing device, and article manufacturing method

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a detection device, a correction device, a processing device, and an article manufacturing method. 
     Description of the Related Art 
     There is a technique of correcting the optical axis of laser light emitted from a laser light source. As such a method of adjusting the laser optical axis, Japanese Patent Laid-Open No. H4-351282 discloses providing two movable mirrors and two sensors on the optical axis, calculating the amount of driving of the two movable mirrors from information on positional deviation of the detected laser light, and realizing the correction of optical axis deviation of the laser light by moving the laser light a predetermined amount. 
     In Japanese Patent Laid-Open No. H4-351282, laser light emitted from a laser oscillator is reflected by two mirrors disposed on the optical axis. Each of the mirrors is provided with two pairs of rotation mechanisms and two sets of actuators, and can be adjusted to a desired angle with a two-axis degree of freedom. A portion of the laser light that has passed through the mirrors is received by two sensors, and the two-dimensional position of the laser light is detected. 
     This detection value is input to an arithmetic control device connected to the actuator, and the operation of the actuator is controlled to adjust the angles of the two mirrors, thereby correcting the optical axis position and angle of the laser light. 
     However, in Japanese Patent Laid-Open No. H4-351282, position information cannot be accurately detected due to variations in the sensitivity of the two sensors. In addition, if a positional relationship (distance) between the two sensors changes due to thermal effects or the like, a measurement error occurs. In addition, in Japanese Patent Laid-Open No. 2000-114636, laser light is split into two light beams and guided to a detection unit with different optical path lengths, and the angle of the laser light is obtained from the position of one split light beam, and the position of the laser light is obtained from the position of the other light beam, but a measurement error may occur even with this method. 
     Consequently, an object of the present invention is to provide an optical axis detection device and an optical axis correction device that make it possible to accurately detect position information on the optical axis of laser light and reduce a measurement error. 
     SUMMARY OF THE INVENTION 
     In order to solve the above problem, according to an aspect of the present invention, there is provided a detection device including: 
     a first split unit configured to split laser light output from a light source into a plurality of light beams; 
     a detection unit configured to detect a position of each of the plurality of light beams; 
     a light guide unit configured to guide the plurality of split light beams to the detection unit with optical path lengths different from each other; and 
     at least one processor or circuit configured to function as: 
     a control unit configured to calculate an angular deviation or a positional deviation of the laser light on the basis of a difference in the position of each of the plurality of light beams detected by the detection unit, 
     wherein the detection unit is one sensor that detects the position of each of the plurality of light beams guided by the light guide unit. 
     Further features of the present invention will become apparent from the following description of embodiments with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a diagram illustrating a configuration example of an optical axis correction unit according to a first embodiment. 
         FIG.  2    is a flow diagram of a correction process for optical axis fluctuation according to the first embodiment. 
         FIGS.  3 A and  3 B  are diagrams illustrating the correction process for optical axis fluctuation according to the first embodiment. 
         FIG.  4    is a flow diagram of a calculation process for optical axis fluctuation. 
         FIG.  5    is a diagram illustrating a configuration example of an optical axis correction unit according to the first embodiment. 
         FIGS.  6 A and  6 B  are diagrams illustrating the arrangement of four pairs of Galvano scanners constituting an actuator mirror unit. 
         FIG.  7    is a flow diagram of an optical axis correction process according to the first embodiment. 
         FIG.  8    is a flow diagram of an optical axis correction process according to a second embodiment. 
         FIG.  9    is a diagram illustrating a configuration example of a laser processing device according to a third embodiment. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     Hereinafter, with reference to the accompanying drawings, favorable modes of the present invention will be described using Embodiments. In each diagram, the same reference signs are applied to the same members or elements, and duplicate description will be omitted or simplified. 
     First Embodiment 
       FIG.  1    is a diagram illustrating a configuration example of an optical axis correction unit  100  according to a first embodiment. The optical axis correction unit  100  is an optical axis correction device that corrects the optical axis position of a laser light beam  101  output from a laser light source such as a laser oscillator or its angle of incidence on a processing target. The optical axis correction unit  100  includes a first actuator mirror  104 , a second actuator mirror  105 , a sampler  106 , a control unit  113 , and a measurement unit  200 . 
     The laser light beam  101  which is output from a light source and incident on the optical axis correction unit  100  is first reflected by two light reflection members, that is, the first actuator mirror  104  and the second actuator mirror  105 . The first actuator mirror  104  and the second actuator mirror  105  can be adjusted to a desired angle with a two-axis degree of freedom by two pairs of rotation mechanisms and two sets of actuators. 
     The laser light beam  101  reflected by the first actuator mirror  104  and the second actuator mirror  105  is then branched in two directions by the sampler  106  that branches (splits) the light at a desired ratio. Most of the laser light beam  101  incident on the optical axis correction unit  100  passes through the sampler  106  and is emitted from the optical axis correction unit  100 , while a portion thereof is reflected by the sampler  106  and sent out to the measurement unit  200 . 
     The measurement unit  200  includes a first half mirror  107  (first split unit), a first mirror  108 , a second mirror  109 , a second half mirror  110  (second split unit), a damper  111 , and a camera  112  (detection unit). 
     A portion of the laser light beam  101  incident on the measurement unit  200  is first branched in two directions, an optical path A 102  and an optical path B 103 , by the first half mirror  107  that branches (splits) the light at a desired ratio. The second half mirror  110  that likewise branches the light at a desired ratio is disposed on the optical path A 102 . A portion of the laser light on the optical path A 102  passes through the second half mirror  110  and is incident on the camera  112 . The first mirror  108  and the second mirror  109  are disposed on the optical path B 103 . 
     The laser light of the optical path B 103  is reflected by the first mirror  108  and the second mirror  109 , and then a portion thereof is reflected by the second half mirror  110  and incident on the camera  112 . The first mirror  108  and the second mirror  109  are disposed on the optical path B 103 , so that the optical path length of the optical path B 103  becomes longer than the optical path length of the optical path A 102 , and the optical path lengths of the optical path A 102  and the optical path B 103  are different from each other. That is, the first mirror  108  and the second mirror  109  are optical members for making the optical path lengths of a plurality of light beams split by the first half mirror  107  different from each other. 
     The second half mirror  110  guides transmitted light on the optical path A 102  and reflected light on the optical path B 103  to different positions on the light receiving surface of a sensor  114  of the camera  112  to be described later. Here, the different positions on the light receiving surface of the sensor  114  are positions at which light beams do not overlap each other on the light receiving surface of one sensor within the camera  112  (one sensor formed on the same semiconductor substrate). 
     The reflected light on the optical path A 102  and the transmitted light on the optical path B 103  which are caused by the second half mirror  110  are shielded and absorbed by the light-absorbing damper  111 . In the first embodiment, the first mirror  108 , the second mirror  109 , and the second half mirror  110  are light guide units that guide a plurality of split light beams to the camera  112  with different optical path lengths. 
     Meanwhile, if the amount of light branched by the sampler  106  is weak enough, and the amount of light from the optical path A 102  and the amount of light from the optical path B 103  are weak enough not to damage the sensor  114 , there is no need to allow a portion of the light to escape to the damper  111  through the second half mirror  110 . In this case, for example, either the light from the optical path A 102  or the light from the optical path B 103  may be reflected by a reflection member and guided to a different position on the light receiving surface of the sensor  114 . 
     In this way, the optical path lengths of the optical path A 102  and the optical path B 103  are set to be different from each other. In  FIG.  1   , the optical path length of the optical path B 103  is longer than that of the optical path A 102 , but it may be reversed. In addition, the first actuator mirror  104  and the second actuator mirror  105  need not be formed in an integrated structure. For example, it is also possible to use a driving mechanism such as a single-axis motor and a positioning mechanism combining three axes of X, Y, and Z and an angle θ of a reflection member such as a mirror that reflects laser light. 
     The camera  112  is provided with one sensor  114 , which measures the incidence positions of two laser light beams from the optical path A 102  and the optical path B 103 , that is, the optical axis positions on the light receiving surface of the sensor  114 , and transmits the measurement result to the control unit  113  serving as a control unit. The sensor  114  is, for example, a charge coupled device (CCD) sensor or a complementary metal oxide semiconductor (CMOS) sensor. 
     The control unit  113  has a CPU (computer) and a memory (ROM, RAM) which are not shown, the CPU controlling each functional block of the optical axis correction unit  100  and performing arithmetic operations necessary therefor in accordance with a computer program loaded from the memory. Specifically, in addition to control of the camera  112 , the optical axis correction unit  100  has a fluctuation component calculation function for the measurement result of the camera  112  and an actuator control function, and controls the angle of the actuator mirror. 
     A series of steps relating to a correction process for optical axis fluctuation in the first embodiment will be described below.  FIG.  2    is a flow diagram of a correction process for optical axis fluctuation according to the first embodiment. Each operation (step) shown in this flowchart can be executed by control of each unit performed by the control unit  113 . 
     In step S 1 , laser light serving as a reference (reference laser light) is first measured and stored. Specifically, the reference laser light is caused to be incident on the optical axis correction unit  100 , and two incidence positions of the laser light beams from the optical path A 102  and the optical path B 103  on the sensor  114  are measured and stored as reference positions (also referred to as reference incidence positions). 
     In step S 2 , the incidence position of laser light which is a target for measurement is measured. Specifically, laser light which is a target for measurement is caused to be incident on the optical axis correction unit  100 , and two incidence positions of the laser light beams from the optical path A 102  and the optical path B 103  on the sensor  114  are measured. 
     In step S 3 , optical axis fluctuation from the reference laser light is calculated. The incidence positions of the two light beams from the optical path A 102  and the optical path B 103  on the sensor  114  change in accordance with a change in the position or angle of the laser light which is a target for measurement incident on the optical axis correction unit  100 . Therefore, the camera  112  calculates a deviation from the reference position, that is, the amount of change from the reference position, from the measurement result in step S 2 . 
     Specifically, the control unit  113  calculates the deviation amount and deviation direction of the optical axis position of each of a plurality of light beams from the reference position on which the reference laser light is incident. The angle component of the optical axis fluctuation (the amount of change in angle) and the position component of the optical axis fluctuation (the amount of change in optical axis position) are calculated on the basis of the calculated deviation amount and deviation direction. The details of this step will be described later. 
     In step S 4 , the optical axis fluctuation of the laser light is corrected. The control unit  113  calculates the angle of the actuator mirror that can resolve the optical axis fluctuation on the basis of the deviation calculated in step S 3 , and drives the actuator mirror. 
     In step S 5 , the camera  112  re-measures the incidence position of the laser light with the sensor  114 . Specifically, after correction, that is, after the actuator mirror is driven, the incidence positions of the two light beams from the optical path A 102  and the optical path B 103  are measured. In step S 6 , it is determined that that the corrected incidence position of the laser light matches the stored reference position with desired accuracy. 
     Specifically, it is determined whether the deviation between the corrected incidence position of the laser light and the reference position is equal to or less than a threshold. In step S 6 , if the deviation is equal to or less than the threshold (Yes), the process ends. On the other hand, if the deviation is not equal to or less than the threshold (No), steps S 3  to S 6  are repeated until the deviation becomes equal to or less than the threshold. 
     Through the series of steps described above, it is possible to correct the optical axis fluctuation of the laser light, and to stabilize the position of the optical axis of the laser light emitted from the optical axis correction unit  100  and the angle of incidence on the processing target with respect to the fluctuation of the laser light incident on the optical axis correction unit  100 . 
       FIGS.  3 A and  3 B  are diagrams illustrating a correction process for optical axis fluctuation according to the first embodiment.  FIG.  3 A  is a diagram partially illustrating the measurement unit  200  in  FIG.  1   , and  FIG.  3 B  is an explanatory diagram of the principle of measurement using the camera  112 . 
     In  FIG.  3 B , a reference optical axis  204  is an optical axis of laser light stored as a reference. An optical axis  201  to be measured is an optical axis in a state where the position and angle of laser light incident on the optical axis correction unit are fluctuated, that is, an optical axis of laser light which is a target for measurement. A sampler surface  205  is a surface that simulates the reflection surface of the sampler  106  in  FIG.  3 A  along the optical axis. 
     An angular deviation θ1 and a positional deviation d1 are fluctuation components of the optical axis  201  to be measured on the sampler surface  205  from the reference optical axis  204 . A first sensor light receiving surface  206  is a surface that simulates the light receiving surface of the sensor  114  through the optical path A 102  in  FIG.  3 A . A second sensor light receiving surface  207  is a surface schematically illustrating the light receiving surface of the sensor  114  through the optical path B 103  in  FIG.  3 A . 
     D1 is a design distance from the light receiving surface of the sampler  106  to the first sensor light receiving surface  206 , and is equivalent to the design optical path length of the optical path A 102  in  FIG.  3 A . D2 is a design distance from the light receiving surface of the sampler  106  to the second sensor light receiving surface  207 , and is equivalent to the design optical path length of the optical path B 103  in  FIG.  3 A . 
     An optical path  202  simulates the optical path of laser light in the optical path A 102  after fluctuation. An optical path  203  simulates the optical path of laser light in the optical path B 103  after fluctuation. In  FIG.  3 A , the light receiving surface of the sensor  114  (sensor light receiving surface) for measuring the light beams on the optical path A 102  and the optical path B 103  is the same, but in  FIG.  3 B , it is simulatively set as two sensor light receiving surfaces corresponding to D1 and D2 from the sampler surface  205 . Therefore, a difference in optical path length between the optical path A 102  and the optical path B 103  in  FIG.  3 A  is a difference between D2 and D1 in  FIG.  3 B . 
     Here, d2 is the amount of incident point movement on the first sensor light receiving surface  206  after optical axis fluctuation, that is, the amount of incident point movement of the optical axis  201  to be measured on the first sensor light receiving surface  206  from the reference optical axis  204 . In addition, d2 simulates a change in the incidence position of light from the optical path A 102  to the sensor  114  in  FIG.  3 A . 
     Similarly, d3 is the amount of incident point movement on the second sensor light receiving surface  207  after optical axis fluctuation, that is, the amount of incident point movement of the optical axis  201  to be measured on the second sensor light receiving surface  207  from the reference optical axis  204 . In addition, d3 simulates a change in the incidence position of light from the optical path B 103  to the sensor  114  in  FIG.  3 A . 
     An angular deviation θ2 is an angle fluctuation component of laser light within the measurement unit  200 , and is coincident with the angular deviation θ1 in principle. 
     A series of steps relating to a method of calculating optical axis fluctuation, that is, detailed steps of step S 3  in  FIG.  2   , will be described below.  FIG.  4    is a flow diagram of a calculation process for optical axis fluctuation. Each operation (step) shown in this flowchart can be executed by the control unit  113 . In step S 11 , the angle component of optical axis fluctuation is calculated on the basis of the measurement result in the camera  112 , specifically, the deviation amount and deviation direction of the optical axis position calculated on the basis of the measurement result in step S 2  of  FIG.  2   . 
     In addition, θ2 in  FIG.  3 B  is represented by atan((d3-d2)/(D2-D1)). Since 02 is coincident with θ1 in principle, the angular deviation θ1 of optical axis fluctuation can be calculated by this formula. 
     In step S 12 , the position component of optical axis fluctuation is calculated on the basis of the measurement result in the camera  112 , specifically, the deviation amount and deviation direction of the optical axis position calculated on the basis of the measurement result in step S 2  of  FIG.  2   . In addition, d1 in  FIG.  3 B  is represented by d2-D1×tan(θ 2 ). The positional deviation d1 which is the position component of optical axis fluctuation can be calculated by this formula. 
     Through the series of steps described above, the angle component and position component of optical axis fluctuation can be calculated from the measurement result in the camera  112 . Meanwhile, by inserting an optical system of which the optical magnification is changed by a combination of lenses and the like into the optical path of the measurement unit  200 , the relative efficiency of the angle component and the position component may be changed. For example, in an optical system with a magnification of  2 , the angle component of the emitted laser light changes by a factor of ½ and the position component thereof changes by a factor of 2 with respect to the fluctuation of the incident laser light. 
     In the first embodiment, although the laser light incident on the optical axis correction unit  100  is branched into the two optical paths A 102  and B 103  having different optical path lengths, it may be branched into a plurality of optical paths having different optical path lengths, and the number of branches is not limited to two. If the number of branches is increased, the accuracy of the calculated fluctuation component increases. 
     In addition, the light from the optical path A 102  and the light from the optical path B 103  may be guided to the light receiving surface of the sensor  114  so that at least some of them overlap each other. In this case, for example, by varying the timing of detecting the optical axis with the sensor  114  using a shutter or the like, the optical axis positions of the light from the optical path A 102  and the light from the optical path B 103  can be measured by one sensor. 
       FIG.  5    is a diagram illustrating a configuration example of an optical axis correction unit  300  according to the first embodiment. Laser light  301  incident on the optical axis correction unit  300  is incident on an actuator mirror unit  302 . The actuator mirror unit  302  is a Galvano scanner comprising a motor and a galvanometer mirror that can adjust the three-axis directions of X, Y, and Z of the laser light  301  and the angle θ, each of which can be adjusted to a desired angle. 
     Thereafter, the laser light  301  is branched in two directions by a sampler  303  that branches light at a desired ratio. Most of the laser light  301  incident on the optical axis correction unit  300  passes through the sampler  303  and is emitted from the optical axis correction unit  300 , and a portion thereof is reflected by the sampler  303  and is sent out to a measurement unit  304 . The sampler  303  in the first embodiment transmits 99.9% of the laser light  301  incident on the optical axis correction unit  300 . 0.1% of the laser light  301  is reflected by the sampler  303  and is incident on the measurement unit  304 . 
     A portion of the laser light  301  incident on the measurement unit  304  passes through a variable magnification optical system  305 . The variable magnification optical system  305  in the first embodiment is set to a magnification of 0.7 by a plurality of lenses. Thereby, the beam diameter after passing through the variable magnification optical system  305  is reduced to 7/10 of that before passing through it. In addition, the angle component of the emitted laser light changes by a factor of 10/7 and the position component thereof changes by a factor of 7/10 with respect to the fluctuation of the incident laser light. 
     The laser light  301  after passing through the variable magnification optical system  305  is branched in two directions of an optical path A 307  and an optical path B 309  by a first half mirror  306  that branches light at a desired ratio. A portion of the laser light on the optical path A 307  passes through a second half mirror  308  that also branches light at a desired ratio, and is incident on a camera  312 . After the laser light on the optical path B 309  is reflected by a first mirror  310  and a second mirror  311 , a portion thereof is reflected by the second half mirror  308  and is incident on the camera  312 . 
     The second half mirror  308  guides the transmitted light on the optical path A 307  and the reflected light on an optical path B 308  to different positions on the light receiving surface of a sensor  316  of the camera  312 . Both the first half mirror  306  and the second half mirror  308  in the first embodiment transmit 50% of the incident laser light  301  and reflect 50% thereof. 
     The reflected light on the optical path A 307  and the transmitted light on the optical path B 309  which are caused by the second half mirror  308  are shielded and absorbed by a light-absorbing damper  313 . In the first embodiment, the optical path length of the optical path B 309  is set to be approximately 2.5 times longer than the optical path A 307 . 
     The camera  312  is provided with one sensor  316 , which measures the incidence positions of the two laser light beams from the optical path A 307  and the optical path B 309  and transmits the measurement result to a control unit  314 . The camera  312  in the first embodiment is a CMOS camera as an example, and performs signal transmission with the control unit  314  through a LAN cable. 
     In addition to control of the camera  312 , the control unit  314  has a fluctuation component calculation function with respect to the measurement result of the camera  312  and an actuator control function, and controls the angle of the actuator mirror. The control unit  314  in the first embodiment includes a PC with camera control and dedicated calculation process software and a driver for a Galvano scanner. In addition to independent operation, the control unit  314  can be remotely operated by a host computer  315  provided outside of the optical axis correction unit  300 . 
     The host computer  315  is an information processing device, and typically a general-purpose computer such as a personal computer is used. That is, the host computer  315  has a built-in CPU serving as a computer, and controls the operation of each unit of the entire device on the basis of a computer program stored in a memory serving as a storage medium. The host computer  315  is connected to the optical axis correction unit  300 , for example, through a network, and can perform control thereof. 
     Partially transmissive optical elements such as samplers and half mirrors may provide a wedge angle on the optical surface as necessary. In the first embodiment, a wedge angle of 1° is set to suppress a ghost light component from the transmission surface. 
       FIGS.  6 A and  6 B  are diagrams illustrating the arrangement of four pairs of Galvano scanners constituting the actuator mirror unit  302 .  FIG.  6 A  is a layout diagram illustrating a Galvano scanner from the same direction as  FIG.  5   , and  FIG.  6 B  is a layout diagram illustrating a Galvano scanner from the A-A cross-sectional direction of  FIG.  5   . 
     Laser light  401  incident on the actuator mirror unit  302  is reflected by a first Galvano scanner  402 , a second Galvano scanner  403 , a third Galvano scanner  404 , and a fourth Galvano scanner  405 , and is incident on a sampler  406 . Transmitted light of the sampler  406  is emitted from the optical axis correction unit  300 , and reflected light is sent out to a measurement unit  407 . 
     A dielectric multilayer film mirror having a reflectance of 99.95% with respect to the laser wavelength was used as the mirror of each Galvano scanner in the first embodiment. A motor angle is detected by an encoder provided inside the Galvano scanner. Each Galvano scanner is connected to a driving control unit  408 . 
     The driving control unit  408  uses an encoder signal of the Galvano scanner to send out a motor driving signal so that the mirror is at a desired angle, and controls the Galvano scanner. Although the driving control unit  408  is a separate unit from the control unit  314  in the first embodiment, the control unit  314  may execute the function of the driving control unit  408 . 
     A calculation process for optical axis fluctuation of the laser light in the first embodiment is the same as the series of steps shown in  FIG.  4   . Although a unit configured to correct optical axis fluctuation in the first embodiment is also the same as in  FIG.  2   , the calculation process and optical axis correction operation of the control unit  314  will be described below in more detail. 
       FIG.  7    is a flow diagram of an optical axis correction process according to the first embodiment. In the first embodiment, an example in which the actuator mirror is constantly driven to perform correction in accordance with the fluctuation of incident laser light (laser light which is a target for measurement) will be described. 
     In step S 31 , the measurement unit  304  first measures the incidence position of the reference laser light. In step S 32 , the control unit  314  stores the incidence position (reference position) of the reference laser light measured by the measurement unit  304 . Specifically, as the reference position, the incidence position and incidence angle of the reference laser light on the sensor  316  are stored. Meanwhile, steps S 31  and S 32  are equivalent to step S 1  in  FIG.  2   . 
     In step S 33 , the laser light which is a target for measurement is incident on the measurement unit  304 . In step S 34 , the camera  312  of the measurement unit  304  measures the incidence position of the laser light which is a target for measurement on the sensor  316 . Here, as an example, the camera  312  is assumed to measure the optical axis angle and position of the laser light at regular intervals, and to transmit the measurement result to the control unit  314 . Meanwhile, step S 34  is equivalent to step S 2  in  FIG.  2   . 
     In step S 35 , the control unit  314  calculates the deviation from the reference position from the measured incidence position of the laser light which is a target for measurement. In step S 36 , the control unit  314  calculates the amount of difference in the angle and position of the laser light which is a target for measurement with respect to the reference optical axis for each measurement result. Meanwhile, steps S 35  and S 36  are equivalent to step S 3  in  FIG.  2   . 
     In step S 37 , the angle of each Galvano scanner for eliminating the amount of difference from the reference optical axis is calculated through software processing of the control unit  314 . The control unit  314  then transmits the calculated angle to the driving control unit  408 . 
     In step S 38 , the driving control unit  408  drives each Galvano scanner at an angle acquired from the control unit  314 , and corrects the fluctuation of the laser light incident on the optical axis correction unit  300 . Meanwhile, steps S 37  and S 38  are equivalent to step S 4  of  FIG.  2   . 
     In step S 39 , the laser light in which the fluctuation has been corrected is then emitted from the optical axis correction unit  300 . 
     With such a configuration, the actuator mirror can be constantly driven to perform correction in accordance with the fluctuation of the incident laser light, and the stability of the laser light emitted from the optical axis correction unit  300  is improved. 
     Meanwhile, in the first embodiment, a portion of the laser light incident on the optical axis correction unit  300  is caused to be incident on the measurement unit  304 , and thus the optical axis position is measured and the optical axis fluctuation component is calculated in parallel with processing of the processing target. However, by causing all of the laser light incident on the optical axis correction unit  300  to be incident on the measurement unit  304 , the correction process for optical axis fluctuation may be performed at a timing different from the processing of the processing target. 
     Second Embodiment 
       FIG.  8    is a flow diagram of an optical axis correction process according to a second embodiment. In the second embodiment, a correction flow for driving the actuator mirror at a timing designated by a user to perform correction for the fluctuation of the incident laser light will be described. 
     In the present flow, the same steps as those in  FIG.  7    of the first embodiment are assigned the same step numbers, and description thereof will be omitted. Meanwhile, in the second embodiment, the camera  312  is also assumed to measure the optical axis angle and position of the laser light at regular intervals, and to transmit the measurement result to the control unit  314  serving as a control unit. 
     In step S 40 , a command for optical axis correction operation is transmitted from the host computer  315 . In step S 41 , the control unit  314  detects the command transmitted from the host computer  315 , and the control unit  314  calculates the amount of difference in the angle and position of the laser light which is a target for measurement with respect to the reference optical axis for each measurement result. In step S 37 , the angle of each Galvano scanner for eliminating the amount of difference from the reference optical axis is calculated through software processing of the control unit  314 . The control unit  314  then transmits the calculated angle to the driving control unit  408 . 
     In step S 38 , the driving control unit  408  drives each Galvano scanner at an angle acquired from the control unit  314 , and corrects the fluctuation of the laser light incident on the optical axis correction unit  300 . In step S 42 , the camera  312  of the measurement unit  304  measures the incidence position of the corrected laser light on the sensor  316 . 
     In step S 43 , the control unit  314  calculates the deviation from the reference position from the measured incidence position of the corrected laser light. In step S 44 , the control unit  314  calculates the amount of difference in the angle and position of the corrected laser light with respect to the reference optical axis for each measurement result. In step S 45 , the control unit  314  determines whether the amount of difference is within a tolerance (threshold) set in advance. 
     In step S 45 , if the amount of difference is not within the tolerance (equal to or less than the threshold) (No), the correction operation for correcting the amount of difference is executed again. Specifically, steps S 37  to S 45  are repeated until the amount of difference is within the tolerance. On the other hand, in step S 45 , if the amount of difference is equal to or less than the threshold (Yes), the correction operation is completed, and the control unit  314  transmits a correction completion command to the host computer  315  in step S 46  to end the correction operation. Meanwhile, steps S 42  to S 45  are equivalent to steps S 5  and S 6  in  FIG.  2   . 
     In the second embodiment, as the tolerance after optical axis correction, an angle of 0.01° and a position of 0.1 mm were set. Meanwhile, it is also possible to cancel the repetition of the correction operation by setting the control unit  314 . In addition, if a dark noise component of the CMOS camera influences or the intensity of the incident laser light changes, image processing such as providing a detection threshold may be performed on the camera side as necessary. 
     In addition, if the incident laser light contains a noise component such as vibration or atmospheric fluctuation, noise reduction means such as an averaging process may be provided on the camera side as necessary. In addition, in order to cope with the characteristics of laser to be used, an optical system such as a beam expander, a polarization control element, or an optical element such as a light attenuation filter may be added before, after, or inside the optical axis correction unit as necessary. 
     According to the second embodiment, since it is possible to perform the optical axis correction process at a user&#39;s desired timing, for example, the correction process does not reduce the productivity of processing, which is advantageous in terms of the improvement of productivity. 
     Third Embodiment 
     Hereinafter, an example of a processing device  500  including an optical element that guides light emitted from the optical axis correction unit  100  shown in the first embodiment to a target will be described. Meanwhile, the optical axis correction unit  300  may be applied.  FIG.  9    is a diagram illustrating a configuration example of a laser processing device  500  according to a third embodiment. 
     The laser processing device  500  in the third embodiment includes the optical axis correction unit  100  shown in the first embodiment at the subsequent stage of a laser oscillator  501  serving as a laser light source. A condensing optical system  502  is disposed at the subsequent stage, and a laser light beam is condensed and radiated onto a processing target  503  dispose on the focal plane. 
     In this configuration, by driving the first actuator mirror  104  and the second actuator mirror  105  of the optical axis correction unit  100 , scanning with the laser light is performed and the processing target  503  can be processed. 
     In the processing device  500 , it is preferable that driving of the actuator mirror for correcting the optical axis fluctuation of the laser light is executed at a different timing from the processing step for the processing target  503 . In other words, it is preferable that driving of the actuator mirror for correcting the optical axis fluctuation is executed at a different timing from a period in which the processing target  503  is being processed by the laser light. By driving the actuator mirror for correcting the optical axis fluctuation at such a timing, it is possible to reduce the influence of the driving on the processing. 
     In addition, it is preferable that the detection of the laser optical axis position for correcting the optical axis fluctuation of the laser light is executed at the same timing as the processing step for the processing target  503 . Setting such a timing makes it possible to efficiently perform the correction process, which is advantageous in terms of the improvement of productivity. 
     Embodiment Relating to Method of Manufacturing Article 
     The processing device according to the embodiments described above can be used in a method of manufacturing an article. The method of manufacturing the article can include a step of processing an object (target) using the processing device and a step of processing an object that has been processed in the step. 
     The processing can include, for example, at least any one of processing different from the processing, transportation, inspection, sorting, assembly, and packaging. The article manufacturing method of first to third embodiments is advantageous in at least one of the performance, quality, productivity, and production cost of an article compared with methods of the related art. 
     OTHER EMBODIMENTS 
     While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation to encompass all such modifications and equivalent structures and functions. For example, the sampler  106 , the measurement unit  200 , the control unit  113 , and the like may be combined and made independent to form one optical axis detection device that calculates the fluctuation component of the optical axis. 
     In addition, as a part or the whole of the control according to the embodiments, a computer program realizing the function of the embodiments described above may be supplied to the detection apparatus or the like through a network or various storage media. Then, a computer (or a CPU, an MPU, or the like) of the detection apparatus or the like may be configured to read and execute the program. In such a case, the program and the storage medium storing the program configure the present invention. 
     This application claims the benefit of Japanese Patent Application No. 2021-178766 filed on Nov. 1, 2021, which is hereby incorporated by reference herein in its entirety.