Patent Publication Number: US-2023150059-A1

Title: Laser processing apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims foreign priority based on Japanese Patent Application No. 2021-186967, filed Nov. 17, 2021, the contents of which are incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The technology disclosed herein relates to a laser processing apparatus. 
     2. Description of Related Art 
     JP 2019-104047 A discloses an example of a laser processing apparatus. 
     Specifically, a laser machining device according to JP 2019-104047 A includes: a laser light deflection section (laser light scanning section) that deflects laser light; a housing that accommodates the laser light deflection section; and an exit window section that is formed on a lower surface of the housing and transmits the laser light deflected by the laser light deflection section. 
     Incidentally, in the laser machining device as disclosed in JP 2019-104047 A, there is a case where a distance (workpiece distance) from the exit window section to a workpiece is set as an index indicating an installation situation in which a preferable machining result is obtained. 
     Further, in a case where the exit window section is formed on the lower surface of the housing as in the laser machining device according to JP 2019-104047 A, it has been conventionally known to adjust a height position of the exit window section so as to achieve the workpiece distance by supporting the lower surface of the housing from below by a predetermined member (hereinafter, referred to as a “support member”) for supporting the housing and adjusting a height of the support member. 
     On the other hand, it is conceivable to set a position of a workpiece corresponding to a workpiece distance set in a laser processing apparatus close to a lower surface of a housing in a height direction in order to reduce an installation space of the laser processing apparatus. However, when the position of the workpiece is brought close to the lower surface of the housing, there is a concern about interference between the support member and the workpiece. 
     SUMMARY OF THE INVENTION 
     The technology disclosed herein has been made in view of such a point, and an object thereof is to suppress interference between a member for supporting a housing and a workpiece while bringing the housing and the workpiece close to each other. 
     According to one embodiment of the disclosure, provided is a laser processing apparatus that is attached to an attachment target position and irradiates an irradiation area with laser light to process a workpiece. The laser processing apparatus includes: a laser light deflection section that deflects the laser light to be emitted toward the irradiation area in accordance with a predetermined processing setting; and a housing that accommodates the laser light deflection section. 
     Further, according to the one embodiment of the disclosure, in the housing, an exit window transmitting the laser light emitted toward the irradiation area via the laser light deflection section, and an attachment surface arranged to face the exit window and attached to the attachment target position are formed. 
     According to the one embodiment, in the housing according to the one embodiment, the attachment surface is formed on an opposite side of the exit window. Since the housing is configured such that not one outer surface on which the exit window is formed, but the attachment surface facing the opposite side thereof is attached to the attachment target position, the housing can be supported to be suspended from the attachment target position. This eliminates the need for interposing the support member between the housing and the workpiece, and thus, the housing and the workpiece can be brought close to each other. 
     At this time, a member (the support member) for supporting the housing is located on the opposite side of the exit window similarly to the attachment target position, and thus, can be sufficiently separated from the workpiece. This makes it possible to suppress the interference between the support member and the workpiece while bringing the housing and the workpiece close to each other. 
     In addition, according to another embodiment of the disclosure, the housing may accommodate: a solid-state laser crystal generating the laser light based on excitation light; and a support plate extending along a direction from the attachment surface toward the exit window and supporting the solid-state laser crystal, and the support plate may be attached to the housing in a state of not being integrated with the attachment surface. 
     According to the another embodiment, it is possible to suppress an influence of distortion, vibration, and the like, generated on the attachment surface at the attachment target position, on the solid-state laser crystal. As a result, the laser light can be favorably generated even in a case where the housing is configured to be supported at the attachment target position. 
     In addition, according to still another embodiment of the disclosure, the attachment surface may be provided with an attachment capable of attaching the attachment surface to the attachment target position. 
     According to the still another embodiment, since the support member provided at the attachment target position and the attachment surface of the housing are connected to each other via the attachment instead of being directly connected, the housing can be attached to the support member that can take various forms without devising a structure of the housing itself. This is advantageous in terms of facilitating replacement of various processing apparatuses with the laser processing apparatus according to the disclosure in a manufacturing line in which use of the various processing apparatuses is assumed. 
     In addition, according to still another embodiment of the disclosure, the housing may include: an exit surface on which the exit window is formed; and an open surface which surrounds the laser light deflection section together with the attachment surface and the exit surface and is at least partially open to communicate with the exit window, and the open surface may be provided with a cover member capable of opening and closing the open surface. 
     According to the still another embodiment, the open surface is configured to be openable and closable, instead of the exit surface facing the workpiece and the attachment surface attached to the attachment target position, so that the exit window can be accessed without causing interference with the workpiece, the support member, and the like. Accordingly, maintainability of the laser processing apparatus can be improved. 
     In addition, according to still another embodiment of the disclosure, the housing may include a connection surface which faces an opposite side of the open surface and surrounds the laser light deflection section together with the open surface, the attachment surface, and the exit surface, and an electric cable for supplying electric power into the housing may be connected to the connection surface. 
     According to the still another embodiment, the open surface provided with the cover member and the connection surface to which the electric cable is connected are located on the opposite side. Interference between the cover member and the electric cable is suppressed when the cover member is opened, closed, attached, or detached. Accordingly, maintainability of the laser processing apparatus can be improved. 
     In addition, according to still another embodiment of the disclosure, the workpiece may be conveyed in a predetermined conveyance direction, the irradiation area may have a constant dimension in the conveyance direction, and a spot diameter of the laser light on the workpiece may be set such that a depth of focus of the laser light corresponds to a portion of the irradiation area where an optical path length of the laser light is longest and a portion of the irradiation area where the optical path length is shortest. 
     In addition, according to still another embodiment of the disclosure, a path corresponding to the irradiation area out of a movement path of the workpiece may include a site having a different distance from the exit window. 
     In addition, according to still another embodiment of the disclosure, the workpiece may be conveyed in a predetermined conveyance direction, a dimension of the irradiation area in the conveyance direction may be 120 mm or more, the laser light deflection section may include a first mirror which deflects the laser light to irradiate the irradiation area, the first mirror may be arranged to face the workpiece across the exit window, a relative position of the workpiece with respect to the housing may be set such that a distance from the first mirror to the workpiece is 150 mm or less, and a spot diameter of the laser light on the workpiece at the relative position may be 60 μm or more. 
     In general, an optical path length difference between a central portion and an end of the irradiation area increases as the dimension of the irradiation area increases. In this case, laser light having a predetermined depth of focus or more is required in order to adopt a configuration in which the optical path length difference is allowed without separately providing a mechanism for adjusting the focus of the laser light. 
     According to findings obtained as results of intensive studies by the inventors of this application, a sufficient depth of focus can be secured by setting the spot diameter of the laser light on the workpiece to 60 μm or more in the layout set as in the still another embodiment. 
     In addition, according still another embodiment of the disclosure, provided is a laser processing apparatus that is supported by a support member connectable to a connection surface in a substantially rectangular parallelepiped printing apparatus including a printing surface on which a printing section that comes into contact with a printing area on a workpiece is exposed and the connection surface different from the printing surface, and emits laser light toward an irradiation area set in accordance with the printing area to process the workpiece. The laser processing apparatus includes: a laser light deflection section that deflects the laser light to be emitted toward the irradiation area in accordance with a predetermined processing setting; and a housing that accommodates the laser light deflection section. 
     Further, according to the still another embodiment of the disclosure, in the housing, an exit window transmitting the laser light emitted toward the irradiation area via the laser light deflection section, and an attachment surface connected to the support member are formed. 
     According to the still another embodiment, in the housing according to the still another embodiment, the exit window corresponding to the printing section in the substantially rectangular parallelepiped printing apparatus and the attachment surface corresponding to the connection surface in the printing apparatus are formed. Here, the support member is configured to be connected to the attachment surface, so that the housing can be supported by the support member from the side or above. As a result, the housing and the workpiece can be brought close to each other as compared with a configuration in which the housing is supported from below. 
     At this time, the support member is located on the side or above the housing in order to support the housing, and thus, can be sufficiently separated from the workpiece. This makes it possible to suppress the interference between the support member and the workpiece while bringing the housing and the workpiece close. 
     In addition, according to still another embodiment of the disclosure, the workpiece may be a workpiece that is conveyed in a state of being placed around a conveyance roller, and the conveyance roller may be arranged to overlap the irradiation area. 
     In addition, according to still another embodiment of the disclosure, the workpiece may be conveyed in a predetermined conveyance direction, a dimension of the irradiation area in the conveyance direction may be 120 mm or more, an output of the laser light transmitted through the exit window may be set to 2 W or less, and a spot diameter of the laser light on the irradiation area may be set to 60 μm or more. 
     According to findings obtained as results of intensive studies by the inventors of this application, it is possible to achieve downsizing of the housing while securing a sufficient depth of focus by adopting the configuration of the still another embodiment. 
     As described above, it is possible to suppress the interference between the member for supporting the housing and the workpiece while bringing the housing and the workpiece close to each other according to the disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a diagram illustrating an overall configuration of a laser processing system; 
         FIG.  2    is a block diagram illustrating a schematic configuration of a laser processing apparatus; 
         FIG.  3 A  is a perspective view illustrating an appearance of a marker head; 
         FIG.  3 B  is a perspective view illustrating the appearance of the marker head; 
         FIG.  4    is a side view of the marker head; 
         FIG.  5    is a perspective view illustrating a state in which a cover member is removed from the marker head; 
         FIG.  6    is a rear view of the marker head; 
         FIG.  7    is a diagram illustrating a connection structure of an electric cable in the marker head; 
         FIG.  8    is a perspective view illustrating an accommodation structure of the marker head; 
         FIG.  9    is a perspective view illustrating the accommodation structure of the marker head; 
         FIG.  10    is a transverse sectional view schematically illustrating an internal structure of the marker head; 
         FIG.  11    is a longitudinal sectional view schematically illustrating the internal structure of the marker head; 
         FIG.  12    is a side view schematically illustrating a main part in a board accommodation section; 
         FIG.  13    is a side view schematically illustrating a main part in a crystal accommodation section; 
         FIG.  14    is a perspective view schematically illustrating a main part in a mirror accommodation section; 
         FIG.  15    is a perspective view for describing deflection of laser light by a laser light scanning section; 
         FIG.  16    is a perspective view for describing the deflection of the laser light by the laser light scanning section; 
         FIG.  17 A  is a schematic view for describing replacement of a printing apparatus and the marker head; 
         FIG.  17 B  is a perspective view for describing attachment of the marker head to the support member; 
         FIG.  18    is a diagram for describing various dimensions of the marker head and the support member; 
         FIG.  19    is a flowchart illustrating a basic control process of the laser processing apparatus; 
         FIG.  20    is a block diagram for describing a circuit structure related to a power supply section; 
         FIG.  21    is a flowchart illustrating a specific example of a control process related to the power supply section; 
         FIG.  22    is a perspective view illustrating a modification of an attachment surface and an attachment; and 
         FIG.  23    is a schematic view illustrating another modification of the attachment surface. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Hereinafter, an embodiment of the disclosure will be described with reference to the drawings. Note that the following description is given as an example. 
     That is, a laser marker is described as an example of a laser processing apparatus in this specification, but the technology disclosed herein can be applied to general laser-applied devices regardless of the names of the laser processing apparatus and the laser marker. 
     In addition, printing will be described as a typical example of processing in this specification, but the technology can be used in various types of processing using laser light such as image marking without being limited to the printing. 
     &lt;Overall Configuration&gt; 
       FIG.  1    is a diagram illustrating an overall configuration of a laser processing system S, and  FIG.  2    is a diagram illustrating a schematic configuration of a laser processing apparatus L in the laser processing system S. In addition,  FIG.  17 A  is a schematic view for describing replacement of a printing apparatus  1001  and a marker head  1 , and  FIG.  17 B  is a perspective view for describing attachment of the marker head  1  to a support member  501 . 
     The laser processing system S illustrated in  FIG.  1    includes the laser processing apparatus L and an external device  400  connected thereto. Among these, the laser processing apparatus L illustrated in  FIGS.  1  and  2    is configured to perform processing corresponding to a predetermined processing pattern Pp on a workpiece W by irradiating a predetermined irradiation area R 1  with laser light. 
     Note that the irradiation area R 1  referred to herein is an area set on the surface of the workpiece W, and can take various forms in accordance with a relative positional relationship between the laser processing apparatus L and the workpiece W, specifications of the laser processing apparatus L, a movement path of the workpiece W, and the like. The irradiation area R 1  according to this embodiment is configured as a rectangular area as illustrated in  FIG.  1   . 
     In particular, the laser processing apparatus L according to this embodiment can emit laser light having a wavelength near 350 nm as the laser light for processing the workpiece W. This wavelength corresponds to a wavelength range of ultraviolet rays. Therefore, the laser light for processing the workpiece W is sometimes referred to as “UV laser light” to be distinguished from other laser light such as near-infrared rays in the following description. Note that laser light other than the ultraviolet rays such as infrared rays may be used for processing the workpiece W. 
     Hereinafter, a case will be described in which the workpiece W made of a sheet-like film is set as an object to be processed, and the film contains a UV-reactive layer that chemically reacts with UV laser light. 
     However, the workpiece W that can be used as the object to be processed is not limited to the film containing the UV-reactive layer in the laser processing apparatus L according to the disclosure. A film that chemically reacts with laser light having a wavelength other than the ultraviolet rays may be used, or the workpiece W made of various materials, such as paper and a synthetic resin, may be used as the object to be processed. 
     In addition, the laser processing apparatus L according to this embodiment is configured to perform so-called two-dimensional printing by performing two-dimensional scanning with laser light, but so-called three-dimensional printing can also be performed since the laser processing apparatus L is configured to have a deep depth of focus as will be described later. Therefore, the laser processing apparatus L can process even the workpiece W conveyed along a three-dimensional movement path as illustrated in  FIG.  18    to be described later. 
     As illustrated in  FIGS.  1  and  2   , the laser processing apparatus L according to this embodiment includes the marker head  1 , a marker controller  100 , an electric cable  200 , and an operation terminal  300 . 
     Among these, the marker controller  100  can receive a setting related to a processing pattern and supply electric power to the outside, and is configured as a controller for controlling the marker head  1 . 
     On the other hand, the marker head  1  can irradiate the irradiation area R 1  with laser light by being controlled by the marker controller  100 . 
     The marker head  1  and the marker controller  100  are separated from each other in this embodiment, and are connected by the electric cable  200 . The electric cable  200  includes at least an electric wiring that transmits the electric power from the inside (specifically, a power supply section  104  to be described later) of the marker controller  100  to the outside. Specifically, the electric cable  200  according to this embodiment is configured by bundling the electric wiring for transmitting the electric power and a signal wiring for transmitting and receiving an analog signal, a digital signal, and the like. 
     The marker head  1  according to this embodiment is installed on the processing equipment  500  that processes the workpiece W made of a sheet-like film. As illustrated in  FIGS.  17 A and  17 B , the processing equipment  500  includes the support member  501  that supports the marker head  1  and a conveyance roller  502  around which the workpiece W is placed. 
     In addition, the processing equipment  500  further includes: two rail members  503   l  and  503   r  that slidably support the marker head  1  via the support member  501 ; two fixing members  505  and  506  to which ends of the two rail members  503   l  and  503   r  are attached, respectively; and a first driven roller  504   l  and a second driven roller  504   r  that are driven when the workpiece W is conveyed by driving of the conveyance roller  502  as illustrated in  FIGS.  17 B,  18   , and the like. At this time, the workpiece W is preferably placed around the conveyance roller  502  such that a length of contact between the conveyance roller  502  and the workpiece W is longer than a length of contact between the first driven roller  504   l  and the workpiece W and longer than a length of contact between the second driven roller  504   r  and the workpiece W. Then, when the conveyance roller  502  conveys the workpiece W, the workpiece W is less likely to slip on the conveyance roller  502 . Note that the “length of contact” used herein refers to the length viewed in a cross section orthogonal to rotation axes of the conveyance roller  502 , the first driven roller  504   l , and the second driven roller  504   r.    
     In this manner, the workpiece W according to this embodiment can be a workpiece that is conveyed in a state of being placed around the conveyance roller  502 , and the conveyance roller  502  used at that time may be arranged so as to overlap the irradiation area R 1  in a vertical direction (Z direction to be described later), for example, as illustrated in  FIG.  1   , a lower diagram of  FIG.  17 A , and  FIG.  18   . 
     The support member  501  can attach the laser processing apparatus L, particularly a housing  10  of the marker head  1 , to a predetermined attachment target position as illustrated in  FIG.  17 A . Although  FIGS.  1 ,  17 A, and  17 B  illustrate the support member  501  configured to suspend the housing  10  from above, the housing  10  may be supported from another direction, such as a side, as will be described later. 
     On the other hand, the conveyance roller  502  is formed in a cylindrical shape having a central axis extending in a lateral direction (front-rear direction to be described later) of the workpiece W. In this case, the workpiece W is conveyed in a longitudinal direction (left-right direction to be described later) along a predetermined movement path by the rotation of the conveyance roller  502 . 
     Here, the processing equipment  500  according to this embodiment is shared between the marker head  1  according to this embodiment and the printing apparatus  1001  that performs printing using a scheme other than laser light as illustrated in the upper diagram and the lower diagram of  FIG.  17 A . 
     That is, the marker head  1  according to this embodiment can be attached to the support member  501  of the processing equipment  500 , configured to attach the printing apparatus  1001 , instead of the printing apparatus  1001 . 
     Examples of the printing apparatus  1001  that can be replaced with the marker head  1  include a thermal transfer overprinter (TTO), but can also be replaced with other printing apparatuses  1001 . 
     As the printing apparatus  1001  that can be replaced with the marker head  1 , for example, any printing apparatus provided with a housing  1010  that is formed in a substantially rectangular parallelepiped shape and includes a printing surface  1010   d  obtained by exposing a printing section  1006  in contact with a printing area on the workpiece W, and a connection surface  1010   u  different from the printing surface  1010   d  and connectable to the support member  501 . 
     In this case, the marker head  1  is supported by the support member  501  connectable to the connection surface  1010   u  similarly to the printing apparatus  1001  as illustrated in the upper diagram and the lower diagram of  FIG.  17 A . The marker head  1  thus supported irradiates the irradiation area R 1  set so as to correspond to the printing area (area in contact with the printing section  1006  in the printing apparatus  1001 ) with laser light, thereby processing the workpiece W. 
     On the other hand, the operation terminal  300  includes, for example, a central processing unit (CPU) and a memory, and is connected to the marker controller  100  so as to be capable of transmitting and receiving an electrical signal in a wired or wireless manner. 
     The operation terminal  300  functions as a terminal configured to set various processing conditions (also referred to as printing conditions) such as printing settings and to display information related to the processing of the workpiece W to a user. The operation terminal  300  includes a display section  301  configured to display information to the user, an operation section  302  that receives an operation input from the user, and a storage apparatus  303  configured to store various types of information. 
     For example, the display section  301  is configured using, for example, a liquid crystal display or an organic EL panel. The operation section  302  can be configured using a keyboard and a pointing device. Here, the pointing device includes a mouse, a joystick, or the like. Instead of the pointing device, the operation section  302  may be configured using, for example, a touch panel console directly connected to the marker controller  100 . 
     The operation terminal  300  configured as described above can set processing conditions in laser processing based on the operation input from the user. The processing conditions include one or more of contents (the processing pattern Pp) of a character string and a figure that need to be printed on the workpiece W, a target output (laser power) of laser light, and a scanning speed (scan speed) of the laser light on the workpiece W. 
     The processing conditions set by the operation terminal  300  are output to the marker controller  100  and stored in the storage section  102  of the marker controller  100 . A storage apparatus  303  in the operation terminal  300  may store the processing conditions if necessary. 
     Note that the operation terminal  300  can be integrated into the marker controller  100 , for example. 
     The external device  400  is connected to the marker controller  100  as necessary. In the example illustrated in  FIGS.  1  and  2   , a conveyance speed sensor  401  and a programmable logic controller (PLC)  402  are provided as the external device  400 . 
     The conveyance speed sensor  401  is configured using, for example, a rotary encoder, and can detect a conveyance speed of the workpiece W. The conveyance speed sensor  401  outputs a signal (detection signal) indicating a detection result to the marker controller  100 . The marker controller  100  controls two-dimensional scanning or the like of laser light based on the detection signal input from the conveyance speed sensor  401 . 
     The PLC  402  is configured using, for example, a microprocessor, and can input a control signal to the marker controller  100 . The PLC  402  is used to control the laser processing system S according to a predetermined sequence. 
     In addition to the above-described devices and apparatuses, an apparatus configured to perform operation and control, a computer configured to perform various other processes, a storage apparatus, a peripheral device, and the like can be connected to the laser processing apparatus L in a wired or wireless manner. 
     Hereinafter, a hardware configuration of each of the marker head  1  and the marker controller  100  will be described in detail, and then, an outline of control of the marker head  1  by the marker controller  100  will be described. 
     &lt;Marker Controller  100 &gt; 
     As illustrated in  FIG.  2   , the marker controller  100  includes: a reception section  101  that receives settings (processing settings) related to the processing conditions including the processing pattern; the storage section  102  that stores the processing conditions; a control section  103  that controls the marker head  1  based on the processing conditions; and the power supply section  104  as a power supplier that supplies electric power to the marker head  1 . 
     (Reception Section  101 ) 
     The reception section  101  is configured to receive the processing conditions input through the operation terminal  300  and output the received processing conditions to the storage section  102  and/or the control section  103 . 
     Specifically, the reception section  101  according to this embodiment is electrically connected to the operation terminal  300 , and can display a setting screen (not illustrated) for setting each processing condition on the display section  301  in the operation terminal  300 . The reception section  101  can reflect a content input through the setting screen in each processing condition and output the processing condition after the reflection to the storage section  102  and/or the control section  103 . 
     (Storage Section  102 ) 
     The storage section  102  is configured to temporarily or continuously store the processing conditions received by the reception section  101 , and output the stored processing conditions to the control section  103 , the display section  301 , or the like if necessary. 
     Specifically, the storage section  102  according to this embodiment is configured using, for example, a non-volatile memory such as a hard disk drive (HDD) or a solid state drive (SSD), and can temporarily or continuously store data indicating the processing conditions. 
     (Control Section  103 ) 
     The control section  103  is configured to execute processing corresponding to a processing condition on the workpiece W by controlling the power supply section  104 , a laser light output section  4 , a laser light scanning section  5 , and the like based on the processing condition. 
     Specifically, the control section  103  according to this embodiment includes a processor, a volatile memory, an input/output bus, and the like. The control section  103  generates a control signal based on the processing condition read from the storage section  102  or directly input from the reception section  101 , and outputs the generated control signal to each section of the laser processing apparatus L to control the processing of the workpiece W. 
     For example, when the processing of the workpiece W is started, the control section  103  reads a target output, which is one of the processing conditions from the storage section  102 , and inputs a control signal generated in relation to the target output to the power supply section  104  or the like, thereby controlling generation of laser excitation light. 
     (Power Supply Section  104 ) 
     The power supply section  104  supplies a drive current to an excitation light generation section  2  based on the control signal output from the control section  103 . Although not described in detail, the power supply section  104  determines the drive current based on the target output input from the control section  103 , and supplies the determined drive current to the excitation light generation section  2 . The power supply section  104  supplies the electric power to the excitation light generation section  2 , and can be configured using a DC power supply  104   a  or the like as illustrated in  FIG.  20    to be described later. Details of the power supply section  104  will be described later. 
     Note that the excitation light generation section  2  configured using an excitation light source, such as a laser diode, is configured to be built in the marker head  1  instead of the marker controller  100  in this embodiment. The electric power supplied from the power supply section  104  is supplied to the excitation light generation section  2  through the electric cable  200 . 
     &lt;Marker Head  1 &gt; 
       FIGS.  3 A and  3 B  are perspective views illustrating an appearance of the marker head  1 .  FIG.  4    is a side view of the marker head  1 ,  FIG.  5    is a perspective view illustrating a state in which a cover member  13  is removed from the marker head  1 , and  FIG.  6    is a rear view of the marker head  1 . 
     In addition,  FIG.  7    is a diagram illustrating a connection structure of the electric cable  200  in the marker head  1 , and  FIGS.  8  and  9    are perspective views illustrating an accommodation structure of the marker head  1 . In addition,  FIG.  10    is a transverse sectional view schematically illustrating an internal structure of the marker head  1 , and  FIG.  11    is a longitudinal sectional view schematically illustrating the internal structure of the marker head  1 . The traverse cross section of  FIG.  10    substantially coincides with a cross section taken along line A-A of  FIG.  11   . 
     In addition,  FIG.  11    is a longitudinal sectional view schematically illustrating the internal structure of the marker head  1 ,  FIG.  12    is a side view schematically illustrating a main part in a board accommodation section H 13 , and  FIG.  13    is a side view schematically illustrating a main part in a crystal accommodation section H 12 . 
     In addition,  FIG.  14    is a perspective view schematically illustrating a main part in a mirror accommodation section H 11 , and  FIGS.  15  and  16    are perspective views for describing deflection of laser light by the laser light scanning section. 
     (Schematic Configuration of Marker Head  1 ) 
     As illustrated in  FIG.  2   , the marker head  1  includes, as main constituent elements, the excitation light generation section  2 , an excitation light guide section  3  as a light guide optical system, the laser light output section  4 , and the laser light scanning section  5  as a laser light deflection section. 
     As will be described in detail later, the excitation light generation section  2  generates excitation light for exciting laser light based on the electric power supplied via the electric cable  200 . The excitation light guide section  3  guides the excitation light generated by the excitation light generation section  2  and inputs the excitation light to the laser light output section  4 . The laser light output section  4  includes a solid-state laser crystal  41  that generates laser light based on the excitation light guided by the excitation light guide section  3 . 
     In addition, the laser light scanning section  5  includes a first scanner  51  that drives a first mirror  51   a  such that the laser light generated by the solid-state laser crystal  41  is emitted toward a desired position in the irradiation area R 1 , and a first control board  53  that controls the first scanner  51 . 
     More specifically, the laser light scanning section  5  according to this embodiment is configured using a so-called biaxial (X-axis and Y-axis) galvano scanner, and further includes a second scanner  52  as an X scanner, in addition to the first scanner  51  as a Y scanner, and a second control board  54  that controls the second scanner  52 . 
     The laser light scanning section  5  controls the first scanner  51  via the first control board  53  and controls the second scanner  52  via the second control board  54 , thereby driving the first mirror  51   a  of the first scanner  51  and the second mirror  52   a  of the second scanner  52 . 
     At that time, the laser light scanning section  5  as the laser light deflection section drives the first mirror  51   a  and the second mirror  52   a  according to a predetermined processing setting (setting related to the processing pattern Pp) to deflect the laser light generated by the laser light output section  4  so as to be emitted toward a desired position in the irradiation area R 1 . 
     The marker head  1  also includes the housing  10  that accommodates the above-described constituent elements, that is, the excitation light generation section  2 , the excitation light guide section  3 , the laser light output section  4 , and the laser light scanning section  5 . In the housing  10 , an exit window  6  that transmits the laser light (that is, the laser light emitted toward the irradiation area R 1  via the laser light scanning section  5 ) deflected by the first mirror  51   a  of the laser light scanning section  5  is formed. 
     Hereinafter, a configuration regarding the appearance of the marker head  1  (specifically, a configuration of six surfaces of the housing  10 ) and the internal structure of the marker head  1  will be described in order. 
     (Outer Surface of Housing  10 ) 
     As illustrated in  FIG.  3 A , the housing  10  of the marker head  1  is configured in a substantially rectangular shape having a longer dimension in the front-rear direction (direction from a right side and a front side to a left side and a depth side in  FIG.  3 A ) as compared with the left-right direction (direction from the left side and the front side when the housing  10  is viewed from the front to the right side and the depth side when the housing  10  is viewed similarly from the front in  FIG.  3 A ). Note that the “left and right” in this specification corresponds to the left and right as viewed from the user facing the housing  10 . 
     Hereinafter, the front-rear direction of the housing  10  is regarded as an X direction, the left-right direction is regarded as a Y direction, and a height direction is regarded as a Z direction. Specifically, the depth side of the plane of the drawing of  FIG.  3 A  in the X direction is regarded as a +X direction, and the front side of the plane of the drawing of  FIG.  3 A  is regarded as a −X direction. Similarly, the front side of the plane of the drawing of  FIG.  3 A  in the Y direction is regarded as a +Y direction, and the depth side of the plane of the drawing of  FIG.  3 A  is regarded as a −Y direction. Similarly, am upper side of the plane of the drawing of  FIG.  3 A  in the Z direction is regarded as a −Z direction, and a lower side of the plane of the drawing of  FIG.  3 A  is regarded as a +Z direction. 
     The definitions based on an outer shape of the housing  10  have been exemplified here for convenience, but definitions based on an operation direction and a positional relationship of each of the constituent elements accommodated in the housing  10  can also be used instead of the definitions or at the same time with the definitions. 
     For example, a first direction that is a deflection direction by the first mirror  51   a  may be defined as the Y direction, and a second direction that is a deflection direction by the second mirror  52   a  may be defined as the X direction. Note that the deflection direction by the mirror included in and driven by the laser light scanning section  5  in this embodiment indicates a direction in which an irradiation position is scanned in the irradiation area R 1  by driving the mirror. That is, the irradiation position in the irradiation area R 1  is scanned in the Y direction as the first mirror  51   a  is driven to rotate. In addition, the irradiation position in the irradiation area R 1  is scanned in the X direction as the second mirror  52   a  is driven to rotate. Similarly, a direction from the marker head  1  toward the irradiation area R 1 , more specifically, an irradiation direction which is a direction from the exit window  6  toward the irradiation area R 1  can be regarded as the Z direction. The irradiation direction may be a direction from the first mirror  51   a  toward the irradiation area R 1 . Note that a “direction from a certain member toward the irradiation area R 1 ” in this embodiment indicates one direction out of an axial direction in which the certain member and the irradiation area R 1  face each other. The “direction from the certain member toward the irradiation area R 1 ” is not a traveling direction of light from the certain member toward the irradiation area R 1 . Therefore, the irradiation position in the irradiation area R 1 , that is, the traveling direction of the light toward the irradiation area R 1  is changed by the rotation of the first mirror  51   a  and the rotation of the second mirror  52   a , but the irradiation direction in this embodiment does not change with the change in the traveling direction of the light. 
     In the following description, a description will be given assuming that the definitions based on the outer shape of the housing  10  coincide with the definitions based on the deflection direction and the irradiation direction of the first mirror  51   a  and the second mirror  52   a  match. 
     As illustrated in  FIGS.  3 A to  7   , the housing  10  has a bottom surface  10   d  on which the exit window  6  is formed, and a top surface  10   u  facing the bottom surface  10   d  and the exit window  6 . For example, the bottom surface  10   d  faces the +Z direction, the top surface  10   u  faces the −Z direction, and both are constituted by one or a plurality of plate-shaped members having a thickness in the Z direction. Note that the expression “facing” used herein indicates conceptual facing in a case where the housing  10  is regarded as a conceptual rectangular parallelepiped. 
     The housing  10  further includes a front surface  10   f , a back surface  10   b , a left side surface  101 , and a right side surface  10   r  surrounding the excitation light generation section  2 , the excitation light guide section  3 , the laser light output section  4 , and the laser light scanning section  5  together with the bottom surface  10   d  and the top surface  10   u.    
     The front surface  10   f , the back surface  10   b , the left side surface  101 , and the right side surface  10   r  all face a direction orthogonal to the top surface  10   u  and the bottom surface  10   d  (that is, a direction along an XY plane). For example, the front surface  10   f  faces the −X direction, the back surface  10   b  faces the +X direction, and both are constituted by one or a plurality of plate-shaped members having a thickness in the X direction. Similarly, for example, the left side surface  101  faces the +Y direction, the right side surface  10   r  faces the −Y direction, and both are constituted by one or more plate-shaped members having a thickness in the Y direction. 
     Hereinafter, the six surfaces of the housing  10  will be described in order. Note that the term “surface” in the bottom surface  10   d , the top surface  10   u , the front surface  10   f , the back surface  10   b , the left side surface  101 , and the right side surface  10   r  also includes a plate-shaped member having a predetermined thickness. In addition, these six surfaces are merely classified for convenience, and do not need to be separated from each other. For example, at least one of the left side surface  101  and the right side surface  10   r  and at least a part of the bottom surface  10   d  (particularly, a non-offset portion  18  to be described later) may be integrated. 
     —Top Surface  10   u—   
     As illustrated in  FIG.  3 A , the top surface  10   u  among the six surfaces constituting the housing  10  is formed in a rectangular plate shape that extends along the X and Y directions and has a longer dimension in the X direction than in the Y direction. The top surface  10   u  according to this embodiment is configured as an attachment surface connected to the support member and attached to the above-described attachment target position. In this case, a plate thickness of the top surface  10   u  is larger than plate thicknesses of the left side surface  101  and the right side surface  10   r.    
     Further, the top surface  10   u  as the attachment surface is provided with an attachment  7  that can be attached to the attachment target position. The attachment  7  is configured as a plate-shaped member that extends along directions (the X and Y directions) substantially parallel to the top surface  10   u  and has a thickness in a direction (the Z direction) orthogonal to the top surface  10   u . The attachment  7  is placed on the top surface  10   u , and is fastened to the top surface  10   u  by a fastener  7   b  such as a bolt, for example, as illustrated in  FIG.  10   . As described above, the plate thickness of the top surface  10   u  is larger than the plate thicknesses of the left side surface  101 , the right side surface  10   r , and the like. The larger plate thickness of the top surface  10   u  is advantageous in securing an insertion allowance for the fastener  7   b.    
     A fastening hole  7   a  corresponding to the support member  501  arranged at the attachment target position is provided in an upper surface of the attachment  7 . The support member  501  can be attached to the attachment  7  by fastening the fastener, such as a bolt, to the fastening hole  7   a  in a state where the support member  501  is placed on the attachment  7 . Accordingly, the top surface  10   u  is attached to the attachment target position via the attachment  7 , and at the same time, the housing  10  is suspended from the support member  501 . 
     —Bottom Surface  10   d—   
     As illustrated in  FIG.  4   , the bottom surface  10   d  among the six surfaces is arranged on an opposite side of the top surface  10   u  with the laser light scanning section  5  interposed therebetween. As illustrated in  FIG.  5   , the bottom surface  10   d  is formed in a curved surface shape that extends along the X direction and has a central portion in the Y direction being recessed toward the −Z side. 
     Specifically, as illustrated in  FIGS.  5  and  10   , the bottom surface  10   d  according to this embodiment includes an offset portion  16   a  that is located at the central portion in the Y direction and offset toward the −Z side, and the non-offset portion  18  that is located at both ends in the Y direction and protrudes more toward the +Z side as compared with the offset portion  16   a . Both the offset portion  16   a  and the non-offset portion  18  are formed to extend flat along the X direction. 
     Specifically, the bottom surface  10   d  according to this embodiment is formed with a groove having a trapezoidal cross section that has the offset portion  16   a  as an upper side and increases in diameter toward the +Z side. The exit window  6  is provided in the offset portion  16   a  as the upper side. The bottom surface  10   d  according to this embodiment is configured as an exit surface on which the exit window  6  is formed. Details of the exit window  6  will be described later. 
     On the other hand, the non-offset portion  18  forms a portion from sites corresponding to oblique sides of the trapezoidal shape to a +Z-side end in the bottom surface  10   d . The non-offset portion  18  according to this embodiment includes: a first plate-shaped member  181  located on the +Y side of the offset portion  16   a ; and a second plate-shaped member  18   r  located on the −Y side of the offset portion  16   a.    
     The first plate-shaped member  181  is formed in a thin plate shape as illustrated in  FIG.  10   , and has an inverted L shape as viewed from the −X side. Here, the “inverted L shape” indicates a shape obtained by inverting an L shape with respect to a symmetry axis extending in the Z direction. The first plate-shaped member  181  is arranged on an opposite side of the second plate-shaped member  18   r  with the offset portion  16   a  interposed therebetween. A vertical side portion of the inverted L shape in the first plate-shaped member  181  forms the oblique side on the +Y side in the trapezoidal shape, and a horizontal side portion of the inverted L shape forms the +Z-side end on the +Y side. 
     The second plate-shaped member  18   r  is formed in a thin plate shape as illustrated in  FIG.  10   , and has an L shape as viewed from the −X side. The second plate-shaped member  18   r  is arranged on an opposite side of the first plate-shaped member  181  with the offset portion  16   a  interposed therebetween. A vertical side portion of the L shape of the second plate-shaped member  18   r  forms the oblique side on the −Y side of the trapezoidal shape, and a horizontal side portion of the L shape forms the +Z-side end on the −Y side. 
     In addition, the first plate-shaped member  181  covers the exit window  6  from the +Y side together with the lower half of the left side surface  101  as illustrated in  FIG.  10   . On the other hand, the second plate-shaped member  18   r  covers the exit window  6  from the −Y side together with the lower half of the right side surface  10   r . In this manner, the first plate-shaped member  181  and the second plate-shaped member  18   r  form a skirt-shaped cover (skirt portion) together with the lower half of the left side surface  101  and the lower half of the right side surface  10   r.    
     —Front Surface  10   f—   
     As illustrated in  FIGS.  3 B and  5   , the front surface  10   f  among the six surfaces is formed in a plate shape that extends along the Y and Z directions and is provided with an indicator  11 , two vents  12  and  12 , and a notch  10   c.    
     As illustrated in  FIGS.  3 B and  5   , the indicator  11  is provided on the upper side and near a right end of the front surface  10   f , and includes three lamps  11   a ,  11   b , and  11   c  arranged side by side along the Y direction (illustrated only in  FIG.  5   ). Each of the three lamps  11   a ,  11   b , and  11   c  includes a light emitting diode (LED) electrically connected to the marker controller  100 . Hereinafter, the three lamps  11   a ,  11   b , and  11   c  are referred to as a first lamp  11   a , a second lamp  11   b , and a third lamp  11   c  in order from the +Y side. 
     The first lamp  11   a  is configured using, for example, a blue LED, and lights up in blue in conjunction with a key switch (not illustrated) provided in the laser processing apparatus L. Note that the “key switch” referred to herein is a switch that is switched by a key managed by a safety manager or the like. An “OFF” state corresponding to a power-off state, a “POWER ON” state corresponding to a power-on state and prohibiting emission of laser light, and a “LASER ON” state corresponding to the power-on state and permitting the emission of the laser light are switched by inserting the key into the laser processing apparatus L and turning the key in a predetermined direction. 
     On the other hand, the second lamp  11   b  is configured to be capable of switching a light emission color to one of green and orange, and the light emission color is switched in accordance with various states in addition to the states of the key switch. In addition, the third lamp  11   c  is configured to be capable of switching the light emission color to any one of green, orange, and red, and the light emission color is switched in accordance with various states in addition to the states of the key switch. 
     Each of the first lamp  11   a , the second lamp  11   b , and the third lamp  11   c  is electrically connected to the marker controller  100 , and is configured to light up in response to the control signal input from the control section  103 . Details of control of the indicator  11  will be described later. 
     As illustrated in  FIGS.  3 B and  5   , one of the two vents  12  and  12  is provided on the lower side and near a left end of the front surface  10   f , and the other of the two vents  12  and  12  is provided on the lower side and near the right end of the front surface  10   f . The two vents  12  and  12  both penetrate through the front surface  10   f  in a thickness direction, and each communicate with a second accommodation section H 2  to be described later. 
     As illustrated in  FIGS.  3 B and  5   , the notch  10   c  is formed by cutting out a site including a lower end of the front surface  10   f , and is connected to a front end (end on the −X direction side) of the offset portion  16   a . The notch  10   c  is arranged between the two vents  12  and  12  in the Y direction. 
     Specifically, the notch  10   c  is formed in a substantially trapezoidal shape whose diameter increases in a tapered shape toward the +Z direction so as to have a cross section substantially coinciding with the trapezoidal cross section having the offset portion  16   a  as the upper side. The front surface  10   f  according to this embodiment is configured as a user access surface (open surface) that is at least partially opened so as to lead to the exit window  6  via the offset portion  16   a  by providing the notch  10   c  in the lower half. 
     —Detail 1 of Front Surface  10   f  (Dust Collector and Camera)— 
     The notch  10   c  according to this embodiment can be used for various uses in addition to a maintenance action of the exit window  6  (for example, a cleaning action performed by inserting a cleaning tool from the notch  10   c ). 
     In general, when the workpiece W, such as a film, is irradiated by a UV laser, smoke is generated. Therefore, a dust collector separate from the marker head  1  may be connected to the front surface  10   f  to suck the smoke through the notch  10   c . Note that the dust collector may be built in the marker head  1  instead of attaching the dust collector to the marker head  1 , such as the connection to the front surface  10   f.    
     In addition, after the workpiece W, such as a film, is irradiated by the UV laser to perform printing processing, a camera may be built in or externally attached to the marker head  1  for the purpose of inspecting a print content thereof. Such a camera may be attached to, for example, the notch  10   c  or attached to the offset portion  16   a . In the former case, a reflection mirror may be provided in the periphery of the exit window  6  such that an image of the irradiation area R 1  can be captured from immediately above (−Z side) as much as possible. In addition, an illumination may be provided in the periphery of the camera or the exit window  6  so as to obtain an image as bright as possible. 
     —Detail 2 of Front Surface  10   f  (Cover Member  13  and Opening and Closing Sensor)— 
     Further, the cover member  13  capable of opening and closing the front surface  10   f  is attached to the front surface  10   f  serving as the open surface. The cover member  13  includes: a first cover portion  13   a  fixed to the upper half of the front surface  10   f  a second cover portion  13   b  that is swingable so as to open and close the lower half of the front surface  10   f , particularly, an open portion by the notch  10   c ; and a hinge mechanism  13   c  that joins the first cover portion  13   a  and the second cover portion  13   b  (see  FIGS.  3 A and  3 B ). 
     The first cover portion  13   a  is formed in a rectangular plate shape covering the upper half of the front surface  10   f , and has through-holes (whose reference signs are omitted) formed at substantially the same positions as the indicator  11 . The first cover portion  13   a  is fixed to the upper half of the front surface  10   f  with the fastener such as a screw. 
     The second cover portion  13   b  is formed in a rectangular plate shape capable of covering the lower half of the front surface  10   f , particularly, the notch  10   c , and has through-holes (whose reference signs are omitted) formed at substantially the same positions as the two vents  12  and  12 . The second cover portion  13   b  is supported to the first cover portion  13   a  via the hinge mechanism  13   c.    
     The hinge mechanism  13   c  is located at a central portion of the front surface  10   f  in the Z direction, and swingably joins an upper edge portion of the second cover portion  13   b  to a lower edge portion of the first cover portion  13   a.    
     The hinge mechanism  13   c  can swing the second cover portion  13   b  about a rotation axis extending in the Y direction in a state where the first cover portion  13   a  is fixed to the front surface  10   f  (see  FIGS.  3 A and  3 B ). As the second cover portion  13   b  is swung in an opening direction, the notch  10   c  of the front surface  10   f  can be exposed. As the notch  10   c  is exposed, various types of maintenance, such as cleaning of the exit window  6 , can be performed through the offset portion  16   a  connected to the notch  10   c.    
     Note that the cover member  13  is not essential. The front surface  10   f  may be exposed without providing the cover member  13 . 
     In addition, an opening and closing sensor that senses opening and closing of the cover member  13  may be provided on at least one of the cover member  13  (particularly, the second cover portion  13   b ) and the front surface  10   f  (particularly, a peripheral portion of the notch  10   c  on the front surface  100  although not illustrated. 
     As such an opening and closing sensor, for example, a magnetic-type sensor including a magnet provided on one of the second cover portion  13   b  and the front surface  10   f  and a magnetic sensor (for example, a Hall element) provided on the other of the second cover portion  13   b  and the front surface  10   f  can be used. Note that the magnetic-type sensor is merely an example, and an optical-type sensor, a mechanical-type sensor, or the like may be used. 
     Such a magnet sensor is electrically connected to the marker controller  100  and/or a circuit board in the marker head  1 , and can output a sensing signal indicating an open or closed state of the cover member  13 , particularly, the second cover portion  13   b , to the marker controller  100  and/or the circuit board. 
     Since such an opening and closing sensor is provided, the open or closed state of the cover member  13  can be sensed, and various types of control based on the open or closed state can be performed. As an example, the marker controller  100  according to this embodiment performs an emergency stop of emission of laser light when the cover member  13  is opened during the emission of the laser light. Thereafter, the cover member  13  is closed to perform an emergency stop releasing operation via the operation section  302 , so that the emission of the laser light can be restarted. 
     Note that, in a case where the cover member  13  is regarded as one outer surface of the housing  10 , the cover member  13  is visually recognized by the user at the time of attaching the marker head  1  or the like. In this case, for example, a first mark M 1  as a mark can be added to the second cover portion  13   b  of the cover member  13  as illustrated in  FIG.  3 A . 
     The first mark M 1  includes: a first center line M 11  indicating a center of the irradiation area R 1  (an intersection where diagonal lines of the irradiation area R 1  intersect); a +Y edge M 12  indicating an edge on the +Y side of the irradiation area R 1 ; and a −Y edge M 13  indicating a center on the −Y side of the irradiation area R 1 . 
     Note that the cover member  13  is not essential. When the front surface  10   f  is regarded as the outer surface of the housing  10  without providing the cover member  13 , the first mark M 1  can be added to the front surface  10   f.    
     —Back Surface  10   b—   
     As illustrated in  FIGS.  3 B and  5   , the back surface  10   b  among the six surfaces is arranged on an opposite side of the front surface  10   f  with the laser light scanning section  5  interposed therebetween, and is formed in a plate shape extending along the Y and Z directions. The back surface  10   b  according to this embodiment can be regarded as one outer surface of the housing  10  (an outer surface different from the cover member  13 ), and forms a connection surface to which the electric cable  200  supplying electric power into the housing  10  is connected. The back surface  10   b  as the connection surface surrounds the laser light scanning section  5  as the laser light deflection section together with the front surface  10   f  as the open surface, the top surface  10   u  as the attachment surface, and the bottom surface  10   d  as the exit surface. 
     Further, the back surface  10   b  as the connection surface is provided with a connection cover  14  that covers a connection portion between the back surface  10   b  and the electric cable  200  as illustrated in  FIG.  7   . The connection cover  14  regulates an extending direction Ae of the electric cable  200  such that the electric cable  200  is drawn out in an in-plane direction (the Y and Z directions) of the back surface  10   b , more specifically, in a direction (the Y direction) intersecting with the irradiation direction (Z direction) out of the in-plane direction (Y and Z directions). 
     In other words, the connection cover  14  is configured to draw out the electric cable  200  along the direction (Y direction or Z direction) orthogonal to the X direction which is a direction connecting the front surface  10   f  and the back surface  1   ob.    
     Specifically, the connection cover  14  according to this embodiment includes: an enclosure portion  14   a  that encloses a connection terminal of the marker head  1  with respect to the electric cable  200 ; a lid  14   b  that closes the enclosure portion  14   a ; a seal member  14   c  that liquid-tightly seals a space between the enclosure portion  14   a  and the lid  14   b ; and a wire diameter conversion connector  14   d  that adjusts a wire diameter of the electric cable  200 . 
     Among them, the enclosure portion  14   a  is formed so as to enclose the connector that is open to the back surface  10   b  from the side (the Y and Z directions). Specifically, the enclosure portion  14   a  according to this embodiment is formed in a thin rectangular box shape that is open in the +X direction. 
     Further, in a case where the enclosure portion  14   a  is regarded as a thin box, two openings (whose reference signs are omitted) communicating with different connection terminals are formed on the bottom surface  14   e . In addition, among a plurality of side walls constituting the enclosure portion  14   a , a left side wall portion  14   f  facing the +Y side is provided with a first through-hole  14   g  penetrating through the left side wall portion  14   f  along the Y direction as the extending direction Ae. As the electric cable  200  is inserted through the first through-hole  14   g , the extending direction Ae thereof is regulated. 
     The wire diameter conversion connector  14   d  is arranged inside the enclosure portion  14   a , and is accommodated in an accommodation space defined by the enclosure portion  14   a  and the lid  14   b . Here, the electric cable  200  according to this embodiment includes: a first cable portion  201  that extends from the marker controller  100  and is connected to the wire diameter conversion connector  14   d ; and a second cable portion  202  that extends from the wire diameter conversion connector  14   d  and is connected to the connection terminal of the marker head  1 . A wire diameter of the second cable portion  202  is set to be smaller than a wire diameter of the first cable portion  201  so as to be suitable for the connection terminal of the marker head  1 . 
     That is, the electric cable  200  is connected to the marker head  1  in a state where the wire diameter has been converted by the wire diameter conversion connector  14   d  in this embodiment. 
     In general, there is a need to change a cable length of the electric cable  200  in accordance with an installation environment of the marker head  1 . Here, in a case where an attempt is made to use the electric cable  200  longer than usual, there is a concern about a voltage drop as compared with a relatively shorter electric cable, and thus, it is conceivable to use the electric cable  200  having a larger wire diameter as a countermeasure thereof. 
     In this manner, the wire diameter of the electric cable  200  can be changed in accordance with the installation environment of the marker head  1 , and thus, it is conceivable to use the wire diameter conversion connector  14   d  as described above, but there is a concern that a connection portion between the first cable portion  201  and the wire diameter conversion connector  14   d  and a connection portion between the second cable portion  202  and the wire diameter conversion connector  14   d  may be wet by water only by simply using the wire diameter conversion connector  14   d.    
     In this regard, the wire diameter conversion connector  14   d  is accommodated in the connection cover  14  as illustrated in  FIG.  7    so that it is possible to suppress each of the above-described connection portions from being wet by water. Accordingly, the marker head  1  can be made conform to a wider installation environment. 
     —Left Side Surface  101 — 
     As illustrated in  FIGS.  3 A,  3 B, and  10   , the left side surface  101  among the six surfaces is arranged on the +Y side with respect to laser light scanning section  5 , and is formed in a plate shape extending along the Z and X directions. 
     Note that, in a case where the left side surface  101  is regarded as one outer surface of the housing  10 , the left side surface  101  is visually recognized by the user at the time of attaching the marker head  1  or the like. As illustrated in  FIG.  3 A , a second mark M 2  as a mark can be added to the left side surface  101 . 
     The second mark M 2  includes: a second center line M 21  indicating the center of the irradiation area R 1  (the intersection where the diagonal lines of the irradiation area R 1  intersect); a +X edge M 22  indicating an edge on the +X side in the irradiation area R 1 ; and a −X edge M 23  indicating an edge on the −X side in the irradiation area R 1 . 
     —Right Side Surface  10   r—   
     As illustrated in  FIGS.  4 ,  5 , and  10   , the right side surface  10   r  among the six surfaces is arranged on the −Y side with respect to the laser light scanning section  5 , and is formed in a plate shape extending along the Z and X directions. The right side surface  10   r  is arranged on an opposite side of the left side surface  101  with the laser light scanning section  5  interposed therebetween. 
     Note that, in a case where the right side surface  10   r  is regarded as one outer surface of the housing  10 , a third mark M 3  configured similarly to the second mark M 2  can be added to the right side surface  10   r.    
     The third mark M 3  includes: a third center line M 31  indicating the center of the irradiation area R 1  (the intersection where the diagonal lines of the irradiation area R 1  intersect); a +X edge M 32  indicating an edge on the +X side in the irradiation area R 1 ; and a −X edge M 33  indicating an edge on the −X side in the irradiation area R 1 . 
     Note that a configuration including both the second mark M 2  and the third mark M 3  is not essential, and one of the second mark M 2  and the third mark M 3  may be provided. 
     (Internal Space of Housing  10 ) 
     The housing  10  defines an internal space surrounded by the six surfaces of the bottom surface  10   d , the top surface  10   u , the front surface  10   f , the back surface  10   b , the left side surface  101 , and the right side surface  10   r . The internal space is partitioned into a plurality of accommodation sections by a plate-shaped member arranged in the housing  10 . 
     As such a plate-shaped member, the marker head  1  according to this embodiment includes a first base plate  15 , a second base plate  16 , and a third base plate  17 . In this embodiment, the first base plate  15 , the second base plate  16 , and the third base plate  17  are separated from each other. In addition, the first base plate  15  is configured as a support plate capable of supporting the solid-state laser crystal  41  among these plate-shaped members. 
     Hereinafter, configurations of the respective plate-shaped members will be described in order. 
     —First Base Plate  15 — 
     As illustrated in  FIGS.  8 ,  9 , and  10   , the first base plate  15  is configured as a metal plate-shaped member extending in the X direction, and is accommodated in the housing  10  (in other words, surrounded by the six surfaces of the housing  10 ). A plate thickness of the first base plate  15  is set to be larger than at least the plate thicknesses of the left side surface  101  and the right side surface  10   r  among the six surfaces of the housing  10 . 
     In particular, the first base plate  15  according to this embodiment has an inverted L shape as viewed from the −X side. Here, the “inverted L shape” indicates a shape obtained by inverting an L shape with respect to a symmetry axis extending in the Z direction. Hereinafter, there is a case where a site corresponding to a vertical side of the inverted L shape in the first base plate  15  is referred to as a vertical side portion  15   a , and a site corresponding to a horizontal side of the inverted L shape is referred to as a horizontal side portion  15   b.    
     The first base plate  15  is arranged between the left side surface  101  and the right side surface  10   r  in the Y direction, and is arranged on the +Y side of the second base plate  16 . The first base plate  15  is arranged on the +Y side of the third base plate  17  with the second base plate  16  interposed therebetween. 
     Here, a seal member (not illustrated) that liquid-tightly seals a gap between the first base plate  15  and the left side surface  101  is provided between a left end (end on the +Y side) of the horizontal side portion  15   b  and the left side surface  101  of the housing  10 . 
     The first base plate  15  is arranged below the top surface  10   u  in the Z direction. 
     Here, as illustrated in an enclosing portion C 1  of  FIG.  10   , an upper end (end on the −Z side) of the vertical side portion  15   a  faces the top surface  10   u  with a predetermined gap. Accordingly, the first base plate  15  is in a state of not being integrated with the top surface  10   u  of the housing  10  (a state of allowing a relative displacement of the first base plate  15  with respect to the top surface  10   u ). 
     Note that, in a case where an outer surface other than the top surface  10   u  among the six surfaces of the housing  10  is the attachment surface, a gap may be provided between the outer surface serving as the attachment surface and the first base plate  15  instead of providing the gap between the top surface  10   u  and the vertical side portion  15   a . For example, in a case where the left side surface  101  of the housing  10  is the attachment surface, a gap can be provided between the left end of the horizontal side portion  15   b  and the left side surface  101 . 
     The first base plate  15  is arranged between the front surface  10   f  and the back surface  10   b  in the X direction. As illustrated in  FIG.  11   , the first base plate  15  is fixed to the front surface  10   f  by a front-surface-side fastener  15   c , and is fixed to the back surface  10   b  by a back-surface-side fastener  15   d.    
     That is, the first base plate  15  as the support plate is attached to the housing  10  through the front surface  10   f  and the back surface  10   b  in the state of not being integrated with the top surface  10   u  as the attachment surface. 
     Next, when describing the vertical side portion  15   a  in detail, the vertical side portion  15   a  according to this embodiment is formed in a thick plate shape that expands along the Z direction as the irradiation direction and the X direction. As illustrated in  FIG.  11   , at least two through-holes  15   e  and  15   f  are formed in the vertical side portion  15   a.    
     Out of the two through-holes  15   e  and  15   f , the second through-hole  15   e  located on the +X side is used to optically couple the excitation light guide section  3  and the laser light output section  4 . The second through-hole  15   e  forms a first entrance window  91  that allows excitation light to enter the laser light output section  4  from the excitation light guide section  3 . 
     Out of the two through-holes  15   e  and  15   f , the third through-hole  15   f  located on the −X side is used to optically couple the laser light output section  4  and the laser light scanning section  5 . An optical member  15   h , such as glass, that transmits laser light is fitted in the third through-hole  15   f . The third through-hole  15   f  and the optical member  15   h  form a second entrance window  92 , which allows the laser light to enter the laser light scanning section  5  from the laser light output section  4 , together with a fifth through-hole  50   b  to be described later. 
     In addition, out of left and right side surfaces of the vertical side portion  15   a , the left side surface facing the +Y side forms a partition surface  15   g  that defines the crystal accommodation section H 12  to be described later. Various optical components including the solid-state laser crystal  41  are fastened to the partition surface  15   g.    
     In addition, out of the left and right side surfaces of the vertical side portion  15   a , the right side surface facing the −Y side supports a first casing  50  that defines the mirror accommodation section H 11  to be described later from the left. The right side surface may define a part of the mirror accommodation section H 11 , instead of supporting the first casing  50  by the right side surface of the vertical side portion  15   a.    
     Next, when describing the horizontal side portion  15   b  in detail, the horizontal side portion  15   b  according to this embodiment is formed in a thick plate shape that expands along the X direction and the Y direction. As illustrated in  FIG.  10   , a first heat sink  81 , which is a heat sink according to this embodiment, is provided on a lower surface of the horizontal side portion  15   b.    
     The first heat sink  81  includes a plurality of fins protruding in the +Z direction. These fins are arranged side by side in the Y direction. Each of the fins is formed to extend in the X direction. The first heat sink  81  is thermally coupled to a constituent component (for example, the solid-state laser crystal  41 ) of the laser light output section  4  via the first base plate  15 . 
     Note that the horizontal side portion  15   b  and the first heat sink  81  are integrated in the example illustrated in  FIG.  10   , but the horizontal side portion  15   b  and the first heat sink  81  may be separated without being limited thereto. 
     —Second Base Plate  16 — 
     As illustrated in  FIGS.  8 ,  9 , and  10   , the second base plate  16  is configured as a metal plate-shaped member extending in the X direction, and defines a part of the six surfaces of the housing  10 , particularly, the offset portion  16   a  of the bottom surface  10   d.    
     In particular, the second base plate  16  according to this embodiment is formed in a Z shape as viewed from the −Y side. An upper side when the second base plate  16  is regarded as the Z shape corresponds to the offset portion  16   a  in this embodiment. In the X direction, a length of the offset portion  16   a  as the upper side is set to be longer than a length of a bottom side when the second base plate  16  is regarded as the Z shape. 
     The second base plate  16  is arranged between the left side surface  101  and the right side surface  10   r  in the Y direction, more specifically, between the first base plate  15  and the third base plate  17 . The second base plate  16  is supported by the first base plate  15  and the third base plate  17  via fasteners (not illustrated) such as screws. 
     The second base plate  16  is arranged below the top surface  10   u  in the Z direction. The second base plate  16  is arranged on the −Z side of the horizontal side portion  15   b  of the first base plate  15 . Specifically, the offset portion  16   a  as the upper side of the Z shape is arranged in the second base plate  16  at substantially the same Z position as a +Z-side portion (lower portion) when the vertical side portion  15   a  of the first base plate  15  is divided into two portions in the Z direction. In addition, a portion of the second base plate  16  corresponding to the bottom side of the Z shape is arranged at substantially the same Z position as +Z-side ends (lower ends) of the left side surface  101  and the right side surface  10   r.    
     Here, a seal member (not illustrated) that liquid-tightly seals a gap between the offset portion  16   a  and the right side surface is provided between a +Y-side end (left end) of the offset portion  16   a  in the second base plate  16  and the right side surface of the vertical side portion  15   a  in the first base plate  15 . 
     Similarly, a seal member (not illustrated) that liquid-tightly seals a gap between the offset portion  16   a  and the left side surface of the vertical side portion  17   a  of the third base plate  17  is provided between a −Y-side end (right end) of the offset portion  16   a  and the left side surface. 
     The second base plate  16  is arranged between the front surface  10   f  and the back surface  10   b  in the X direction. The second base plate  16  is fixed to the front surface  10   f  and the back surface  10   b  via the first base plate  15  and the third base plate  17 . The second base plate  16  may be directly fastened to the front surface  10   f  and the back surface  10   b.    
     Next, when describing the offset portion  16   a  in detail, the offset portion  16   a  according to this embodiment is formed in a thick plate shape that expands along the X direction and the Y direction. Further, the exit window  6  according to this embodiment is formed in a +X-side portion (rear portion in the front-rear direction) when the offset portion  16   a  is divided into two portions in the X direction. 
     The exit window  6  includes: an exit hole  61  penetrating through the +X-side portion of the offset portion  16   a ; a cover glass  62  fitted in the exit hole  61 ; and a seal member (not illustrated) that liquid-tightly seals a gap between the exit hole  61  and the cover glass  62  (see  FIG.  10   ). The cover glass  62  is configured as an optical member that transmits laser light deflected by the laser light scanning section  5  and travels toward the irradiation area R 1 . The cover glass  62  can be formed in a rectangular shape corresponding to the shape of the irradiation area R 1 , for example, a rectangular shape that is substantially similar to the irradiation area R 1  and has a smaller size than the irradiation area R 1 . 
     In addition, an upper surface facing the −Z side between both the upper and lower surfaces of the offset portion  16   a  supports the first casing  50  from below as illustrated in  FIGS.  8 ,  9 , and  10   . More specifically, the first casing  50  can be fastened to the upper surface of the offset portion  16   a , and the first casing  50  can be fixed with respect to the second base plate  16  by this fastening. The upper surface may define a part of the mirror accommodation section H 11 , instead of supporting the first casing  50  by the upper surface of the offset portion  16   a.    
     —Third Base Plate  17 — 
     As illustrated in  FIGS.  8 ,  9 , and  10   , the third base plate  17  is configured as a metal plate-shaped member extending in the X direction, and is accommodated in the housing  10  (in other words, surrounded by the six surfaces of the housing  10 ). A plate thickness of the third base plate  17  is set to be larger than at least the plate thicknesses of the left side surface  101  and the right side surface  10   r  among the six surfaces of the housing  10 . 
     In particular, the third base plate  17  according to this embodiment has an L shape as viewed from the −X side. Hereinafter, there is a case where a site corresponding to a vertical side of the L shape in the third base plate  17  is referred to as a vertical side portion  17   a , and a portion corresponding to a horizontal side of the L shape is referred to as a horizontal side portion  17   b.    
     The third base plate  17  is arranged between the left side surface  101  and the right side surface  10   r  in the Y direction, and is arranged on the −Y side of the second base plate  16 . The third base plate  17  is arranged on the −Y side of the first base plate  15  with the second base plate  16  interposed therebetween. 
     Here, a seal member (not illustrated) that liquid-tightly seals a gap between the third base plate  17  and a right side surface  10   r  of the housing  10  is provided between a right end (end on the +Y side) of the horizontal side portion  17   b  of the third base plate  17  and the right side surface  10   r.    
     The third base plate  17  is arranged below the top surface  10   u  in the Z direction. 
     The third base plate  17  is arranged between the front surface  10   f  and the back surface  10   b  in the X direction. The third base plate  17  is fixed to the front surface  10   f  and the back surface  10   b  by fasteners (not illustrated). 
     Next, when describing the vertical side portion  17   a  of the third base plate  17  in detail, the vertical side portion  17   a  according to this embodiment is formed in a thick plate shape that expands along the −Z direction as the irradiation direction and the X direction. In the Z direction, a dimension of the vertical side portion  17   a  of the third base plate  17  is shorter than a dimension of the vertical side portion  15   a  of the first base plate  15 . The vertical side portion  17   a  supports the second base plate  16  from the −Y side. 
     Next, when describing the horizontal side portion  17   b  of the third base plate  17  in detail, the horizontal side portion  17   b  according to this embodiment is formed in a thick plate shape that expands along the X direction and the Y direction. Various components can be attached to the horizontal side portion  17   b . The components attached to the horizontal side portion  17   b  include the first control board  53  of the laser light scanning section  5 . In addition, a second heat sink  82  serving as a heat sink according to this embodiment is provided on a lower surface of the horizontal side portion  15   b  facing the −Z side as illustrated in  FIG.  10   . 
     The second heat sink  82  includes a plurality of fins protruding in the +Z direction. These fins are arranged side by side in the Y direction. Each of the fins is formed to extend in the X direction. The second heat sink  82  is thermally coupled to a constituent component (for example, the excitation light source  21 ) of the excitation light generation section  2  via the third base plate  17 . 
     That is, the first heat sink  81  for cooling the laser light output section  4  is configured separately from the second heat sink  82  for cooling the excitation light generation section  2  in this embodiment. 
     Note that the horizontal side portion  17   b  and the second heat sink  82  are integrated in the example illustrated in  FIG.  10   , but the horizontal side portion  17   b  and the second heat sink  82  may be separated without being limited thereto. 
     In addition, when the first base plate  15  and the third base plate  17  are separated as in this embodiment, the first heat sink  81  provided on the first base plate  15  and the second heat sink  82  provided on the third base plate  17  are separated from each other. However, the disclosure is not limited to such a configuration, and the first heat sink  81  and the second heat sink  82  can be integrated. 
     (Outline of First Accommodation Section H 1  and Second Accommodation Section H 2 ) 
     As described above, the internal space of the housing  10  is partitioned into the plurality of accommodation sections by the first base plate  15 , the second base plate  16 , and the third base plate  17 . 
     As such accommodation sections, a first accommodation section H 1  provided with the cover glass  62  as the optical member and the second accommodation section H 2 , obtained by forming at least a part of the periphery of the cover glass  62  to protrude toward the irradiation area R 1  from the cover glass  62 , are formed in the housing  10  according to this embodiment (see a broken line S 1  in  FIG.  10   ). 
     The first accommodation section H 1  and the second accommodation section H 2  are arranged side by side along the irradiation direction (−Z direction), the first accommodation section H 1  is arranged on one side (−Z side) in the irradiation direction, and the second accommodation section H 2  is arranged on the other side (+Z side) in the irradiation direction. A boundary between the first accommodation section H 1  and the second accommodation section H 2  is defined by the first base plate  15 , the second base plate  16 , and the third base plate  17 . 
     The first accommodation section H 1  accommodates optical components related to the generation of excitation light, the generation of laser light, and the deflection of laser light. Specifically, the first accommodation section H 1  according to this embodiment accommodates the excitation light generation section  2 , the excitation light guide section  3 , the laser light output section  4 , and the laser light scanning section  5 . 
     In the example illustrated in  FIG.  10   , the first accommodation section H 1  is configured as a space surrounded by the top surface  10   u , an upper portion of the front surface  10   f , a lower portion of the back surface  10   b , an upper portion of the left side surface  101 , an upper portion of the right side surface  10   r , a portion of the bottom surface  10   d  configured by the second base plate  16 , the first base plate  15 , and the third base plate  17 . 
     On the other hand, the second accommodation section H 2  accommodates cooling components related to cooling of optical components accommodated in the first accommodation section H 1 . Specifically, the second accommodation section H 2  according to this embodiment accommodates the first heat sink  81  and the second heat sink  82  thermally coupled to the optical components accommodated in the first accommodation section H 1 , a first blower fan  83  as a blower that blows air to the first heat sink  81 , and a second blower fan  84  as a blower that similarly blows air to the second heat sink  82 . 
     In the example illustrated in  FIG.  10   , the second accommodation section H 2  is configured as a space surrounded by a lower portion of the front surface  10   f , the lower portion of the back surface  10   b , a lower portion of the left side surface  101 , a lower portion of the right side surface  10   r , a portion of the bottom surface  10   d  configured using the non-offset portion  18  excluding the offset portion  16   a , the first base plate  15 , and the third base plate  17 . 
     In addition, out of the first accommodation section H 1  and the second accommodation section H 2 , at least the first accommodation section H 1  is configured to satisfy the IP standard defined by the International Electrotechnical Commission (IEC). Accordingly, the marker head  1  can be washed with water without wetting the optical components, such as the solid-state laser crystal  41  and the first mirror  51   a , by water. This contributes to improvement of ease of cleaning of the marker head  1 . 
     In addition, the housing  10  forming the first accommodation section H 1  and the second accommodation section H 2  can also have an appearance shape in which water is less likely to be accumulated at the time of washing with water. Such an appearance shape can be achieved by, for example, inclining the top surface  10   u  with respect to the XY plane. Such an appearance shape contributes to improvement of sanitary properties of the marker head  1 . 
     At that time, the front surface  10   f  is configured to be opened and closed by the cover member  13  as described above, wiping (particularly, wiping the periphery of the exit window  6 ) after washing with water becomes easy. This contributes to improvement of maintainability of the marker head  1 . 
     (Details of First Accommodation Section H 1 ) 
     Here, out of the first accommodation section H 1  and the second accommodation section H 2  described above, the first accommodation section H 1  is further partitioned into three accommodation sections arranged side by side in a direction (X or Y direction) orthogonal to the irradiation direction, for example, the Y direction. Specifically, the housing  10  according to this embodiment includes the mirror accommodation section H 11 , the crystal accommodation section H 12 , and the board accommodation section H 13 . 
     The mirror accommodation section H 11  accommodates the first mirror  51   a  and the second mirror  52   a  in the laser light scanning section  5 . The mirror accommodation section H 11  according to this embodiment is defined by the first casing  50  capable of airtightly sealing the first mirror  51   a  and the second mirror  52   a . The first casing  50  may be defined using the offset portion  16   a  as described above. In a case where the first casing  50  is defined using the offset portion  16   a , a cushioning material is preferably provided between the offset portion  16   a  and the first casing  50 . The offset portion  16   a  is a part of the bottom surface  10   d , and thus, is easily affected by distortion, vibration, and the like, and the cushioning material can suppress the first casing and members accommodated in the first casing by the cushioning material from being affected by such an external influence. Alternatively, the mirror accommodation section H 11  may be defined using the first base plate  15  similarly to the crystal accommodation section H 12  to be described later. 
     Here, the first casing  50  is formed in a bottomed box shape that is open toward the −Z side. The first casing  50  is held by the first base plate  15 . 
     A dimension of the first casing  50  in the X direction substantially coincides with a dimension of the offset portion  16   a  in the X direction. Similarly, a dimension of the first casing  50  in the Y direction substantially coincides with a dimension of the offset portion  16   a  in the Y direction. 
     A −Z-side opening of the first casing  50  can be closed by, for example, the lid  59  illustrated in  FIG.  10   . For example, the opening of the first casing  50  may be sealed by the top surface  10   u , instead of sealing the opening by the lid  59 . When the opening of the first casing  50  is sealed by the top surface  10   u , the cushioning material is preferably provided between the top surface  10   u  and the first casing  50 . Accordingly, it is possible to suppress the influence of distortion, vibration, and the like generated on the top surface  10   u  from reaching the first casing  50  and the members accommodated in the first casing. 
     In addition, at least four through-holes  50   a ,  50   b ,  50   c , and  50   d  are formed in the first casing  50 . Among the four through-holes  50   a ,  50   b ,  50   c , and  50   d , the fourth through-hole  50   a  formed in a left side wall portion of the first casing  50  communicates with the third through-hole  15   f  of the first base plate  15  by assembly of the marker head  1 , and constitutes the second entrance window  92  together with the third through-hole  15   f  and the optical member  15   h  fitted in the third through-hole  15   f.    
     On the other hand, among the four through-holes  50   a ,  50   b ,  50   c , and  50   d , the fifth through-hole  50   b  formed at a bottom of the first casing  50  is arranged on the +X side when the first casing  50  including the offset portion  16   a  is divided into two portions in the X direction. A defocus lens  57  as an optical element is provided in the fifth through-hole  50   b . The defocus lens  57  will be described later. 
     In addition, among the four through-holes  50   a ,  50   b ,  50   c , and  50   d , the sixth through-hole  50   c  formed in a right side wall portion (wall portion located on the −Y side) of the first casing  50  is arranged on the +X side when the first casing  50  including the offset portion  16   a  is divided into two portions in the X direction. A second motor  52   b  constituting the second scanner  52  can be inserted and fixed to the sixth through-hole  50   c.    
     In addition, among the four through-holes  50   a ,  50   b ,  50   c , and  50   d , the seventh through-hole  50   d  formed in a rear wall portion (wall portion located on the +X side) of the first casing  50  is arranged on the +X side when the first casing  50  including the offset portion  16   a  is divided into two portions in the X direction. In the Z direction, the seventh through-hole  50   d  is arranged on the +Z side of the sixth through-hole  50   c . In addition, in the Y direction, a center of the seventh through-hole  50   d  (a center of a circle when the seventh through-hole  50   d  is regarded as having a circular cross section) is arranged at substantially the same position as an optical axis of the cover glass  62 . A first motor  51   b  constituting the first scanner  51  can be inserted and fixed to the seventh through-hole  50   d.    
     The crystal accommodation section H 12  is defined by the support plate (the first base plate  15 ) having the partition surface  15   g  extending along the irradiation direction, and is arranged on an opposite side (in the illustrated example, the +Y side) of the mirror accommodation section H 11  with respect to the partition surface  15   g  to accommodate the solid-state laser crystal  41 . The crystal accommodation section H 12  accommodates optical components constituting the laser light output section  4 , such as the solid-state laser crystal  41 . The crystal accommodation section H 12  is defined by the second casing  40  capable of airtightly sealing such optical components. The crystal accommodation section H 12  according to this embodiment can accommodate a non-linear optical crystal  45  in a sealed state. 
     Here, the second casing  40  is formed in a bottomed box shape that is open toward the −Y side. The second casing  40  is attached to the vertical side portion  15   a  of the first base plate  15 , and is supported from the −Y side by the partition surface  15   g  of the vertical side portion  15   a . A −Y-side opening of the second casing  40  can be closed by the partition surface  15   g.    
     In addition, an internal space of the crystal accommodation section H 12  can be divided into both a Q-switch accommodation section H 121  and a wavelength conversion section H 122  arranged side by side in the X direction. The Q-switch accommodation section H 121  is a space that accommodates a Q switch  43 . The wavelength conversion section H 122  is a space that accommodates a non-linear optical crystal  35 . 
     Here, the Q-switch accommodation section H 121  and the wavelength conversion section H 122  are arranged side by side along the X direction, and both are configured as spaces surrounded by the second casing  40  and the partition surface  15   g . More specifically, the second casing  40  is constituted by a box-shaped body corresponding to the Q-switch accommodation section H 121  and a box-shaped body corresponding to the wavelength conversion section H 122 , and each of the Q-switch accommodation section H 121  and the wavelength conversion section H 122  is a space surrounded by each of the box-shaped bodies and the partition surface  15   g . The Q-switch accommodation section H 121  and the wavelength conversion section H 122  are optically coupled by an optical member (not illustrated). Since the Q-switch accommodation section H 121  and the wavelength conversion section H 122  are configured as separate spaces in this manner, the possibility of a decrease in output of laser light due to adhesion of impurities, generated in the Q switch  43  to be described later, to the wavelength conversion element  45  to be described later is reduced. 
     The board accommodation section H 13  is arranged on an opposite side of the crystal accommodation section H 11  with respect to the mirror accommodation section H 12 , and accommodates the first control board  53 . The board accommodation section H 13  according to this embodiment is defined as a space excluding the mirror accommodation section H 11  and the crystal accommodation section H 12  out of the internal space of the first accommodation section H 1 . 
     That is, in this embodiment, the expression that “a predetermined member is accommodated in the mirror accommodation section H 11 ” indicates that the member is surrounded by the first casing  50  on six sides, and the expression that “a predetermined member is accommodated in the crystal accommodation section H 12 ” indicates that the member is surrounded by the second casing  40  and the partition surface  15   g  on six sides. 
     On the other hand, the expression that “a predetermined member is accommodated in the board accommodation section H 13 ” merely indicates that the member is arranged in a space other than the mirror accommodation section H 11  and the crystal accommodation section H 12  in the housing  10 . Of course, the invention is not limited to such a configuration, and a casing (so-called third casing) dedicated to the board accommodation section H 13  may be provided similarly to the first casing  50  and the second casing  40 . 
     (Details of Second Accommodation Section H 2 ) 
     Meanwhile, the second accommodation section H 2  is defined as a +Z-side portion in the housing  10  by the first plate-shaped member  181  and the second plate-shaped member  18   r  as plate-shaped members. The second accommodation section H 2  has two spaces arranged at an interval in a direction orthogonal to the irradiation direction, for example, the direction (Y direction) in which the mirror accommodation section H 11 , the crystal accommodation section H 12 , and the board accommodation section H 13  are arranged. 
     As such two spaces, the second accommodation section H 2  according to this embodiment includes a crystal-side accommodation section H 21  and a light-source-side accommodation section H 22 . Here, since the crystal-side accommodation section H 21  and the light-source-side accommodation section H 22  are arranged apart from each other in the Y direction, a space that does not belong to the second accommodation section H 2  is defined between the crystal-side accommodation section H 21  and the light-source-side accommodation section H 22 . 
     The first plate-shaped member  181  and the second plate-shaped member  18   r  according to this embodiment are configured to define a space including an optical path (optical path on the +Z side) closer to the irradiation area R 1  among optical paths of laser light connecting the first mirror  51   a  as a scanner mirror and the irradiation area R 1 , in addition to the second accommodation section H 2  as the space for accommodating the members. Hereinafter, this space is referred to as an “optical path defining section”, and this space is denoted by reference sign H 3 . The optical path defining section H 3  according to this embodiment is configured as a space surrounded on three sides of the +Y side, the −Y side, and the −Z side by the first plate-shaped member  181 , the second plate-shaped member  18   r , and the cover glass  62 . 
     Note that the optical path defining section H 3  is configured as a space whose lower end on the +Z side is open in the illustrated example, but is not limited to such a configuration. The +Z-side end of the optical path defining section H 3  may be covered with an optical member such as glass. The optical member covering the +Z-side end of the optical path defining section H 3  may be provided alternatively to the cover glass  62  or may be used in combination with the cover glass  62 . 
     In addition, out of the two spaces constituting the second accommodation section H 2 , the crystal-side accommodation section H 21  accommodates the first heat sink  81  and the first blower fan  83 . The first heat sink  81  and the first blower fan  83  are arranged side by side in the X direction. 
     Although overlapping with the above description, the first heat sink  81  according to this embodiment is thermally coupled to at least an optical component attached to the first base plate  15  among the optical components constituting the laser light output section  4 . 
     On the other hand, the first blower fan  83  is arranged on the +X side of the first heat sink  81  as illustrated in  FIG.  13   . The first blower fan  83  is configured using a so-called axial fan, and generates airflow passing through the first heat sink  81  in accordance with a control signal received from the marker controller  100 . The first blower fan  83  may be arranged on the −X side of the first heat sink  81 . Since electric power and a signal for driving the first blower fan are supplied via the electric cable  200  whose connection portion is covered by the connection cover  14  provided on the +X side in this embodiment, a space required for wiring is reduced if the first blower fan  83  is provided on the +X side of the first heat sink  81 , which is advantageous for downsizing the marker head  1 . 
     The airflow generated by the first blower fan  83  flows into the crystal-side accommodation section H 21  from the vent  12  provided in the front surface  10   f  of the housing  10  as indicated by an arrow Al 1  in  FIG.  13   . The airflow that has flowed in then flows from the −X side toward the +X side along the X direction, thereby passing through the first heat sink  81  and the first blower fan  83 . The airflow that has passed through the first blower fan  83  flows out from an air outlet provided in the back surface  10   b  of the housing  10  as indicated by an arrow A 12  in  FIG.  13   . 
     Here, a first rectifying plate  85  that adjusts a flow direction of the airflow is attached to the back surface  10   b  of the housing  10  (see also  FIG.  6   ). The first rectifying plate  85  guides the flow direction of the airflow flowing out from the back surface  10   b  to an opposite side (the −Z side) of a direction from the housing  10  toward the workpiece W as indicated by an arrow A 13  in  FIG.  13   . Accordingly, it is advantageous in terms of suppressing a collision between discharged air and the workpiece W and stabilizing a posture of the workpiece W. 
     The light-source-side accommodation section H 22  accommodates the second heat sink  82  and the second blower fan  84 . The second heat sink  82  and the second blower fan  84  are arranged side by side in the X direction. 
     The second heat sink  82  according to this embodiment is thermally coupled to at least the excitation light source  21  attached to the third base plate  17  among the optical components accommodated in the board accommodation section H 13 . 
     On the other hand, the second blower fan  84  is arranged on the +X side of the second heat sink  82  as illustrated in  FIG.  12   . The second blower fan  84  is configured using an axial fan similarly to the first blower fan  83 , and generates airflow passing through the second heat sink  82  in accordance with a control signal received from the marker controller  100 . The second blower fan  84  may be arranged on the −X side of the second heat sink  82 . Since electric power and a signal for driving the first blower fan are supplied via the electric cable  200  whose connection portion is covered by the connection cover  14  provided on the +X side in this embodiment, a space required for wiring is reduced if the first blower fan  83  is provided on the +X side of the second heat sink  82 , which is advantageous for downsizing the marker head  1 . 
     The airflow generated by the second blower fan  84  flows into the light-source-side accommodation section H 22  from the vent  12  provided in the front surface  10   f  of the housing  10  as indicated by an arrow Ar 1  in  FIG.  12   . The airflow that has flowed in then flows from the −X side toward the +X side along the X direction, thereby passing through the second heat sink  82  and the second blower fan  84 . The airflow that has passed through the second blower fan  84  flows out from an air outlet provided in the back surface  10   b  of the housing  10  as indicated by an arrow Ar 2  in  FIG.  12   . 
     Here, a second rectifying plate  86  that adjusts a flow direction of the airflow is attached to the back surface  10   b  of the housing  10  (see also  FIG.  6   ). The second rectifying plate  86  changes a flow direction of the airflow flowing out from the back surface  10   b  to the opposite side (−Z side) of the direction from the housing  10  toward the workpiece W as indicated by an arrow Ar 3  in  FIG.  12   . Accordingly, it is advantageous in terms of suppressing a collision between discharged air and the workpiece W and stabilizing a posture of the workpiece W. 
     Hereinafter, configurations of the excitation light generation section  2 , the excitation light guide section  3 , the laser light output section  4 , the laser light scanning section  5 , and the like provided in the first accommodation section H 1  of the first accommodation section H 1  and the second accommodation section H 2  will be described in detail with reference to relative positional relationships in the housing  10 . 
     (Excitation Light Generation Section  2 ) 
     The excitation light generation section  2  includes: the excitation light source  21  that generates laser excitation light (excitation light) based on electric power (a drive current) supplied from the power supply section  104 ; a metal plate  22  that supports the excitation light source  21 ; a temperature control section  23  that adjusts a temperature of the excitation light source  21 ; and a light source control board  24  that supports the excitation light source  21  based on a control signal input from the marker controller  100 . 
     The excitation light source  21 , the metal plate  22 , the temperature control section  23 , and the light source control board  24  constituting the excitation light generation section  2  are all accommodated in the board accommodation section H 13 . Accordingly, the excitation light generation section  2 , particularly the excitation light source  21 , is arranged on an opposite side of the laser light output section  4  with the mirror accommodation section H 11  interposed therebetween. Accordingly, the excitation light generation section  2  and the laser light output section  4  can be separated as much as possible. 
     —Metal Plate  22 — 
     The metal plate  22  is configured as a thin plate-shaped member made of metal. As illustrated in  FIGS.  11  and  12   , the metal plate  22  is placed on a −X-side portion when the third base plate  17  is divided into three portions, that is, a +X-side portion, a central portion, and the −X-side portion, in the X direction. The metal plate  22  is fastened to an upper surface of the third base plate  17  (more specifically, an upper surface of the horizontal side portion  17   b  of the third base plate  17 ), and is thermally coupled to the second heat sink  82  via the third base plate  17 . 
     In addition, the excitation light source  21  is placed on an upper surface of the metal plate  22 , and the temperature control section  23  having a plate shape is sandwiched between a lower surface of the metal plate  22  and the third base plate  17 . 
     —Excitation Light Source  21 — 
     The excitation light source  21  is configured to receive electric power supplied from power supply section  104  through the electric cable  200 , and generate excitation light corresponding to the electric power. An output of the excitation light generated by the excitation light source  21  increases as a drive current increases. 
     The excitation light source  21  according to this embodiment is configure using a laser diode (LD). Laser light oscillated from the excitation light source  21  is collected by a focusing lens (not illustrated) or the like and is output as laser excitation light (excitation light). The excitation light source  21  is optically coupled to a fiber cable  31  forming the excitation light guide section  3 . The laser excitation light output from the excitation light source  21  is guided to the excitation light guide section  3  via the fiber cable  31 . 
     In addition, the excitation light source  21  is formed in a rectangular thin plate shape, and is fixed to the upper surface of the metal plate  22  in a posture with its thickness direction along the Z direction as illustrated in  FIGS.  11  and  12   . The excitation light source  21  is arranged at the −X-side portion when the third base plate  17  is divided into the three portions in the X direction, which is similar to the metal plate  22 . With this arrangement, the excitation light source  21  according to this embodiment is arranged close to an upstream end (an −X-side end separated from the second blower fan  84 ) of the airflow generated by the second blower fan  84  other than a downstream end (an +X-side end adjacent to the second blower fan  84 ) of the airflow. 
     In addition, one side surface of the excitation light source  21  obliquely faces the +X side and the +Y side, and an upstream end of the fiber cable  31  is connected to this obliquely facing side surface. 
     —Temperature Control Section  23 — 
     The temperature control section  23  is configured to adjust the temperature of excitation light source  21  to fall within a predetermined temperature range. Here, the temperature range (predetermined temperature range) achieved by the temperature control section  23  is set based on a guarantee environment of the marker head  1 , preferably set to be higher than the guarantee environment of the marker head  1 , and more preferably set to 40° C. or higher and 60° C. or lower. 
     Specifically, the temperature control section  23  according to this embodiment is configured using a substantially thin plate-shaped Peltier element, and is sandwiched between the upper surface (more specifically, the upper surface of the horizontal side portion  17   b ) of the third base plate  17  and the lower surface of the metal plate  22 . The temperature control section  23  discharges heat of the metal plate  22 . A harness (not illustrated) for supplying a current to the temperature control section  23  is connected to a side portion of the temperature control section  23 . The temperature control section  23  absorbs heat at the surface on the metal plate  22  side by the current supplied via the harness, and generates heat at the surface on the third base plate  17  side. 
     —Light Source Control Board  24 — 
     The light source control board  24  is electrically connected to the marker controller  100 , and controls electric power supplied from the power supply section  104  to the excitation light source  21 . 
     The light source control board  24  according to this embodiment is configured using a circuit board having a substantially rectangular thin plate shape. The light source control board  24  is arranged in a posture with both front and back surfaces extending along the Z and X directions, and is fastened to, for example, the vertical side portion  17   a  of the third base plate  17  from the −Y side (whose fastening structure is not illustrated). 
     The light source control board  24  is also arranged on the −Z side of the excitation light source  21  in the Z direction as illustrated in  FIG.  12   , and is electrically connected to the excitation light source  21  by wiring (not illustrated). 
     (Excitation Light Guide Section  3 ) 
     The excitation light guide section  3  as a light guide optical system includes the fiber cable  31  optically coupling the excitation light source  21  and the solid-state laser crystal  41  in the laser light output section  4 , and a fiber guide  32  configured to wind the fiber cable  31  with a predetermined bending radius. The fiber cable  31  and the fiber guide  32  are both accommodated in the board accommodation section H 13  in the housing  10 . 
     —Fiber Cable  31 — 
     The fiber cable  31  is configured using a so-called optical fiber, and has one end (one end as viewed in a light propagation direction) being connected to the excitation light source  21  and the other end (end located on an opposite side of the one end in the light propagation direction) being connected to the first entrance window  91 . 
     The other end of the fiber cable  31  is optically coupled to the solid-state laser crystal  41  via the first entrance window  91  and a first deflection mirror  42  to be described later. In addition, at least a part of a middle site connecting the one end and the other end of the fiber cable  31  is wound around the fiber guide  32 . 
     The fiber cable  31  can guide the excitation light generated in the excitation light source  21  to the solid-state laser crystal  41 . 
     —Fiber Guide  32 — 
     The fiber guide  32  is configured to wind the fiber cable  31  with the predetermined bending radius. The bending radius of the fiber guide  32  is set to be equal to or larger than a minimum bending radius of the fiber cable  31 . 
     Specifically, the fiber guide  32  according to this embodiment is formed in a substantially cylindrical reel shape capable of winding the fiber cable  31  several times. The fiber guide  32  is arranged in a posture with a central axis of the cylindrical shape along the Y direction, and is attached to the vertical side portion  17   a  of the third base plate  17  from the −Y side. 
     In addition, the fiber guide  32  is arranged in a range from a front end of the light source control board  24  to a rear end of the second control board  54  in the X direction as illustrated in  FIG.  12   . As illustrated in  FIG.  11   , the fiber guide  32  is arranged on the +Y side of the light source control board  24  and the second control board  54  and on the −Y side of the right side wall portion of the first casing  50  in the Y direction. 
     (Laser Light Output Section  4 ) 
     The laser light output section  4  includes: the first deflection mirror  42  that bends an optical path of excitation light; the solid-state laser crystal  41  that generates a fundamental wave based on the excitation light; the Q switch  43  that performs pulsed oscillation of the fundamental wave based on a control signal input from the marker controller  100 ; and a first reflection mirror  44  that reflects the fundamental wave. These optical components are airtightly accommodated in the Q-switch accommodation section H 12  obtained by dividing the crystal accommodation section H 121  into two portions. Note that at least the solid-state laser crystal  41  among these optical components can also be accommodated in the wavelength conversion section H 122 . 
     The laser light output section  4  also includes: the non-linear optical crystal  45  that receives the laser light (fundamental wave) generated by the solid-state laser crystal  41  and converts a wavelength of the laser light to a shorter wavelength side; the second reflection mirror  46  that forms a resonant optical path together with the first reflection mirror  44 ; a laser light separation section  47  for separating the laser light whose wavelength has been converted to the short wavelength side from the resonant optical path; and a second deflection mirror  48  that bends an optical path of the laser light separated by the laser light separation section  47 . These optical components are airtightly accommodated in the wavelength conversion section H 12  obtained by dividing the crystal accommodation section H 122  into two portions. 
     In particular, the laser light output section  4  according to this embodiment is configured as a so-called intra-cavity laser oscillator. That is, the Q switch  43 , the first deflection mirror  42 , the solid-state laser crystal  41 , a first separator  47   a  constituting the laser light separation section  47 , a second wavelength conversion element  45   b  as the non-linear optical crystal  45 , and a first wavelength conversion element  45   a  as the non-linear optical crystal  45  are arranged in this order on the way from the first reflection mirror  44  to the second reflection mirror  46 . In other words, the first reflection mirror  44 , the second reflection mirror  46 , and the respective members between the first reflection mirror  44  and the second reflection mirror  46  constitute a resonance unit, and the first wavelength conversion element  45   a  and the second wavelength conversion element  45   b  are arranged inside the resonance unit. The laser light output section  4  is configured as the intra-cavity laser oscillator in this embodiment, but may be an extra-cavity laser oscillator in which the non-linear optical crystal  45  is not located between the first reflection mirror  44  and the second reflection mirror  46 . 
     Here, the first deflection mirror  42  is arranged so as to merge the optical axis (optical axis extending along the Y direction as indicated by reference sign A 1  in  FIG.  11   ) of the excitation light guided by the excitation light guide section  3  and passing through the first entrance window  91  and the optical axis (optical axis extending along the X direction) of the resonant optical path as indicated by reference sign A 2  in  FIGS.  11  and  12   . 
     In addition, for example, the first separator  47   a  is arranged so as to separate laser light including a third harmonic wave from the resonant optical path connecting the first reflection mirror  44  and the second reflection mirror  46 . That is, the laser light output section  4  converts a wavelength of the laser light containing photons stimulated and emitted from the solid-state laser crystal  41  to the shorter wavelength side while amplifying the laser light by multiple reflection between the first reflection mirror  44  and the second reflection mirror  46 . The laser light thus amplified is separated by the laser light separation section  47  and output from the laser light output section  4 . 
     In addition, the laser light output section  4  includes a Q-switch driver  49  that drives the Q switch  43  as a component arranged outside the crystal accommodation section H 12 . As illustrated in  FIG.  13   , the Q-switch driver  49  is attached to a +X-side portion obtained by dividing the top surface  10   u  into two portions in the X direction. The Q-switch driver  49  is also arranged on the +Y side of the vertical side portion  15   a  of the first base plate  15 . 
     Note that the Q-switch driver  49  may be attached to the left side surface  101 , the back surface  10   b , or the like of the housing  10 . The Q-switch driver  49  can be attached to a plate-shaped member constituting the outer surface of the housing  10 . 
     —First Reflection Mirror  44 — 
     The first reflection mirror  44  is accommodated in the Q-switch accommodation section H 121  and is configured to reflect at least the fundamental wave. The first reflection mirror  44  constitutes a resonator together with the second reflection mirror  46 . Note that the first reflection mirror  44  according to this embodiment is configured as a total reflection mirror that reflects the fundamental wave. 
     In addition, the first reflection mirror  44  according to this embodiment is attached to the partition surface  15   g  that defines the crystal accommodation section H 12 , and is thermally coupled to the first heat sink  81  via the first base plate  15 . 
     —Second Reflection Mirror  46 — 
     The second reflection mirror  46  is accommodated in the wavelength conversion section H 122 , and is configured to reflect at least the fundamental wave. The second reflection mirror  46  constitutes the resonator together with the first reflection mirror  44 . Note that the second reflection mirror  46  according to this embodiment is configured as a total reflection mirror that reflects a second harmonic wave having a higher wavelength than the fundamental wave and a third harmonic wave having a higher wavelength than the second harmonic wave in addition to the fundamental wave. 
     In addition, the second reflection mirror  46  according to this embodiment is attached to the partition surface  15   g  similarly to the first reflection mirror  44 , and is thermally coupled to the first heat sink  81  via the first base plate  15 . In this manner, the first reflection mirror  44  and the second reflection mirror  46 , which are both ends of the resonant optical path, are preferably positioned by the same first base plate  15  in order to form the resonant optical path with high accuracy as described above. 
     —Q Switch  43 — 
     The Q switch  43  is accommodated in the Q-switch accommodation section H 121 , and is configured to perform pulsed oscillation of the fundamental wave generated by the solid-state laser crystal  41 . Specifically, the Q switch  43  is arranged to be located on the optical axis of the resonant optical path (optical path of the resonator), and is interposed between the solid-state laser crystal  41  and the first reflection mirror  44 . 
     The Q switch  43  according to this embodiment is a so-called active Q switch that operates based on an RF signal applied from the Q-switch driver  49 . That is, if the Q switch  43  is temporarily turned into an on-state, the laser light incident on the Q switch  43  is deflected and separated from the resonant optical path. In this case, the multiple reflection of the laser light is restricted, and as a result, generation of an inverted distribution in the solid-state laser crystal  41  is promoted. 
     Further, if the Q switch  43  is switched from the on-state to an off-state for a predetermined period, the laser light is subjected to multiple reflection without being separated by the Q switch  43 , and is amplified by the multiple reflection. In this case, the high-output laser light is pulse-oscillated. 
     In addition, the Q switch  43  according to this embodiment is attached to the partition surface  15   g  similarly to the first reflection mirror  44  or the like, and is thermally coupled to the first heat sink  81  via the first base plate  15 . 
     —Q-Switch Driver  49 — 
     The Q-switch driver  49  is accommodated inside the housing  10  and outside the crystal accommodation section H 12 , and generates the RF signal to be applied to the Q switch  43  based on a control signal input from the marker controller  100 . 
     The Q-switch driver  49  is attached to the top surface  10   u  via a metal support plate, and is thermally coupled to the housing  10  via the support plate and the top surface  10   u.    
     —First Deflection Mirror  42 — 
     The first deflection mirror  42  is accommodated in the Q-switch accommodation section H 121  and is arranged between the Q switch  43  and the solid-state laser crystal  41  in the X direction. The first deflection mirror  42  according to this embodiment is configured using a so-called beam splitter. The first deflection mirror  42  totally reflects the excitation light incident from the first entrance window  91  toward the +Y side to propagate along the X direction. On the other hand, the first deflection mirror  42  transmits the fundamental wave propagating along the X direction without reflecting the fundamental wave. The fundamental wave transmitted through the first deflection mirror  42  reaches the first reflection mirror  44  via the Q switch  43 . 
     In addition, the first deflection mirror  42  according to this embodiment is attached to the partition surface  15   g  similarly to the first reflection mirror  44  or the like, and is thermally coupled to the first heat sink  81  via the first base plate  15 . 
     —Solid-State Laser Crystal  41 — 
     The solid-state laser crystal  41  is accommodated in the Q-switch accommodation section H 121  and is made of a laser medium capable of forming an inverted distribution. The solid-state laser crystal  41  is configured to perform stimulated emission corresponding to incident laser excitation light when the laser excitation light is incident on an end surface thereof. A wavelength (so-called fundamental wavelength) of photons emitted by the stimulated emission increases or decreases depending on a specific configuration of the solid-state laser crystal  41 , and is in an infrared range of about 1 μm in this embodiment. 
     In this embodiment, rod-shaped Nd:YVO 4  (yttrium vanadate) is used as laser media constituting the solid-state laser crystal  41 . Laser excitation light is incident from one end surface of the rod-shaped solid-state laser crystal  41 , and laser light having a fundamental wavelength (so-called fundamental wave) is emitted from the other end surface (so-called unidirectional excitation scheme by end pumping). In this example, the fundamental wavelength is set to 1064 nm. On the other hand, a wavelength of the laser excitation light is set to the vicinity of a center wavelength of an absorption spectrum of Nd:YVO 4  in order to promote stimulated emission. However, rare earth-doped YAG, YLF, GdVO 4 , and the like, for example, can be used as other laser media without being limited to this example. Various solid-state laser media can be used in accordance with an application of the laser processing apparatus L. 
     In addition, the solid-state laser crystal  41  according to this embodiment is attached to the partition surface  15   g  similarly to the first reflection mirror  44  or the like, and is thermally coupled to the first heat sink  81  via the first base plate  15 . 
     —Non-Linear Optical Crystal  45 — 
     The non-linear optical crystal  45  is configured by combining the first wavelength conversion element  45   a  that receives the fundamental wave generated by the solid-state laser crystal  41  and generates the second harmonic wave having a wavelength higher than the wavelength of the fundamental wave and the second wavelength conversion element  45   b  that generates the third harmonic wave having a higher wavelength than the second harmonic wave. The first wavelength conversion element  45   a  and the second wavelength conversion element  45   b  are both accommodated in the wavelength conversion section H 122 . 
     The first wavelength conversion element  45   a  is a non-linear optical crystal capable of generating the second harmonic wave, and is configured to double a frequency of the fundamental wave and emit the fundamental wave as the second harmonic wave (Second Harmonic Generation: SHG) when the fundamental wave is incident. That is, a wavelength of laser light generated when the fundamental wave is incident on the first wavelength conversion element  45   a  is in a visible light region of around 500 nm. In particular, the wavelength of the second harmonic wave is set to 532 nm in the present embodiment. 
     In general, the conversion efficiency by the first wavelength conversion element  45   a  is lower than 100%. Therefore, when the fundamental wave is incident on the first wavelength conversion element  45   a , laser light in which the fundamental wave and the second harmonic wave are mixed is emitted. 
     Note that LBO (LiB 3 O 3 ) is used as the first wavelength conversion element  45   a  in this embodiment. However, various organic non-linear optical materials, inorganic non-linear optical materials, and the like can be used as the first wavelength conversion element  45   a  without being limited to this example. 
     The second wavelength conversion element  45   b  is a non-linear optical crystal capable of generating the third harmonic wave, and is configured to convert the fundamental wave and the second harmonic wave into the third harmonic wave having a frequency three times the frequency of the fundamental wave and emit the third harmonic wave (Third Harmonic Generation: THG) when the fundamental wave and the second harmonic wave are incident (particularly, when propagation directions of the fundamental wave and the second harmonic wave are equal to each other). That is, a wavelength of laser light generated when the fundamental wave and the second harmonic wave are incident on the second wavelength conversion element  45   b  is in an ultraviolet region (specifically, in the vicinity of a boundary between the visible light region and the ultraviolet region) of around 350 nm. In particular, the wavelength of the third harmonic wave is set to 355 nm in the present embodiment. 
     In general, the conversion efficiency by the second wavelength conversion element  45   b  is lower than 100%. Therefore, when the fundamental wave and the second harmonic wave are incident on the first wavelength conversion element  45   a , laser light in which the fundamental wave, the second harmonic wave, and the third harmonic wave are mixed is emitted. 
     Note that LBO (LiB 3 O 3 ) is used as the second wavelength conversion element  45   b  in this embodiment. However, various organic non-linear optical materials, inorganic non-linear optical materials, and the like can be used as the second wavelength conversion element  45   b  without being limited to this example. 
     In addition, the non-linear optical crystal  45  according to this embodiment is attached to the partition surface  15   g  similarly to the first reflection mirror  44  or the like, and is thermally coupled to the first heat sink  81  via the first base plate  15 . 
     —Laser Light Separation Section  47 — 
     The laser light separation section  47  is accommodated in the wavelength conversion section H 122 , and is configured to separate the third harmonic wave from the resonant optical path of laser light to generate UV laser light for laser processing. 
     The laser light separation section  47  includes a plurality of optical components. Specifically, the laser light separation section  47  according to this embodiment includes: the first separator  47   a  for extracting the second harmonic wave and the third harmonic wave from the laser light; a concave lens  47   b  for adjusting a beam diameter of the laser light including the second harmonic wave and the third harmonic wave; and a second separator  47   c  for extracting the third harmonic wave from the laser light. 
     The first separator  47   a  is a so-called beam splitter, and is configured to transmit the fundamental wave and reflect the second harmonic wave and the third harmonic wave. The first separator  47   a  is arranged to cross the optical axis of the resonant optical path connecting the first reflection mirror  44  and the second reflection mirror  46 , and is in a posture inclined by approximately 45 degrees with respect to the optical axis. The laser light reflected by the first separator  47   a  propagates toward the −Z side. 
     The concave lens  47   b  is configured to transmit the laser light reflected by the first separator  47   a , that is, the laser light separated from the resonant optical path, thereby expanding the beam diameter of the transmitted laser light. In this embodiment, the concave lens  47   b  is interposed between the first separator  47   a  and the second separator  47   c , but is not limited to such an arrangement. 
     The second separator  47   c  is a beam splitter similar to the first separator  47   a , and is configured to transmit the second harmonic wave and reflect the third harmonic wave. The second separator  47   c  is arranged to cross an optical axis of the laser light having passed through the concave lens  47   b , and is in a posture inclined by approximately 45 degrees with respect to the optical axis. The laser light reflected by the second separator  47   c  propagates toward the −X side. 
     In addition, the optical components constituting the laser light separation section  47  are attached to the partition surface  15   g  similarly to the first reflection mirror  44  or the like, and are thermally coupled to the first heat sink  81  via the first base plate  15  (see also  FIG.  10   ). 
     In this manner, all the first reflection mirror  44 , the second reflection mirror  46 , the Q switch  43 , the first deflection mirror  42 , the solid-state laser crystal  41 , the non-linear optical crystal  45 , and the laser light separation section  47  are preferably positioned by the same first base plate  15  in order to generate the laser light in the optical path with high accuracy. 
     —Second Deflection Mirror  48 — 
     The second deflection mirror  48  is accommodated in the wavelength conversion section H 122 , and is arranged on the −X side of the other optical members accommodated in the crystal accommodation section H 12 . The second deflection mirror  48  according to this embodiment is configured using a so-called beam splitter. The second deflection mirror  48  reflects the laser light passing through the second separator  47   c  and propagating toward the −X side. The laser light reflected by the second deflection mirror  48  is deflected to propagate toward the −Y side. 
     In addition, the second deflection mirror  48  according to this embodiment is attached to the partition surface  15   g  similarly to the first reflection mirror  44  or the like, and is thermally coupled to the first heat sink  81  via the first base plate  15 . In this manner, the second deflection mirror  48  that emits the laser light from the laser light output section  4  to the outside is preferably positioned by the first base plate  15  similarly to the first reflection mirror  44  or the like in order to improve the accuracy of a position where the generated laser light is output. 
     Finally, the laser light deflected by the second deflection mirror  48  passes through the second entrance window  92  and enters the first casing  50  from the laser light output section  4 . As illustrated in  FIG.  11   , the laser light entering the first casing  50  propagates toward the −Y side and reaches the third deflection mirror  56  of the laser light scanning section  5 . 
     (Laser Light Scanning Section  5 ) 
     The laser light scanning section  5  includes an intermediate deflection section  55 , a third deflection mirror  56 , the defocus lens  57  as the optical element, and the first casing  50  that accommodates at least the first mirror  51   a  of the first scanner  51  and the second mirror  52   a  of the second scanner  52 , in addition to the first scanner  51  and the second scanner  52 , the first control board  53  and the second control board  54  described above. 
     Hereinafter, these constituent elements will be described in order of arrival of laser light during laser oscillation. 
     —Third Deflection Mirror  56 — 
     As illustrated in  FIG.  11   , the third deflection mirror  56  is accommodated in the first casing  50 , is arranged to be arranged side by side with the second deflection mirror  48  and the second entrance window  92  along the Y direction, and is located on the −Y side of these members. The third deflection mirror  56  is arranged between the second entrance window  92  and the light source control board  24  in the Y direction (in other words, on the −Y side of the second entrance window  92  and on the +Y side of the light source control board  24 ). 
     The third deflection mirror  56  is configured using, for example, a total reflection mirror, receives the laser light entering the first casing  50  and propagating toward the −Y side, and reflects the laser light toward the +X side. The laser light reflected by the third deflection mirror  56  reaches the second mirror  52   a  of the second scanner  52 . Note that the third deflection mirror  56  may be configured using a mirror that partially transmits the laser light, instead of the total reflection mirror. In this case, the output of the laser light entering the first casing  50  from the laser light output section  4  may be detected using the partially transmitted laser light. 
     —Second Scanner  52 — 
     As illustrated in  FIGS.  14 ,  15 , and  16   , the second scanner  52  includes the second mirror  52   a  that scans laser light in a predetermined second direction, and the second motor  52   b  that rotatably supports the second mirror  52   a . Among them, the second mirror  52   a  is accommodated in the mirror accommodation section H 11 , and most of the second motor  52   b  is accommodated in the board accommodation section H 13 . 
     The second mirror  52   a  is configured as a so-called galvanometer mirror. The second mirror  52   a  receives the laser light generated by the solid-state laser crystal  41  via the third deflection mirror  56  and the like illustrated in  FIG.  11   . The second mirror  52   a  reflects the received laser light toward the +Z side to deflect the laser light. As the second mirror  52   a  rotates, an irradiation position of the laser light in the irradiation area R 1  is scanned in the second direction. 
     Here, the second direction that is the deflection direction by the second mirror  52   a  is a direction orthogonal to both the first direction that is the deflection direction by the first mirror  51   a  of the first scanner  51  and the −Z direction as the irradiation direction, and is set to coincide with the X direction in this embodiment. 
     Specifically, the second mirror  52   a  is a total reflection mirror having a substantially rectangular plate shape, and is accommodated in the mirror accommodation section H 11  in a state of being supported by a distal end of a rotation axis of the second motor  52   b . The second mirror  52   a  rotates integrally with a shaft of the second motor  52   b , and is configured to be rotated about a predetermined second rotation axis Ac 2  by the second motor  52   b . The amount of deflection by the second mirror  52   a  and an irradiation position of laser light in the second direction are determined based on a rotation angle of the second mirror  52   a  about the second rotation axis Ac 2 . 
     Here, the second rotation axis Ac 2 , which is a rotation center of the second mirror  52   a , extends to be orthogonal to both a first rotation axis Ac 1 , which is a rotation center of the first mirror  51   a , and the Z direction as the irradiation direction as illustrated in  FIGS.  14  and  15   , and is set to extend along the Y direction in this embodiment. 
     The second mirror  52   a  is also arranged to be arranged side by side with the third deflection mirror  56  along the X direction, and is located on the +X side of the third deflection mirror  56 . The second mirror  52   a  is further located on the −Y side of the first mirror  51   a  and the defocus lens  57  in the Y direction, and is located on the −Z side of the first mirror  51   a  and the defocus lens  57  in the Z direction. 
     The second motor  52   b  is a galvano motor configured using a DC motor or the like, and is formed in a substantially cylindrical shape with the second rotation axis Ac 2  as a central axis. The distal end (+Y-side end) of the second motor  52   b  in a direction of the second rotation axis Ac 2  (Y direction) is inserted into the sixth through-hole  50   c  of the first casing  50 . On the other hand, the other end (−Y-side end of the second motor  52   b ) located on an opposite side of the distal end in the direction of the second rotation axis Ac 2  protrudes from the sixth through-hole  50   c  and is exposed inside the board accommodation section H 13 . 
     The second scanner  52  reflects laser light through the second mirror  52   a . The laser light reflected by the second mirror  52   a  is emitted from the exit window  6  via the intermediate deflection section  55 , the first mirror  51   a , and the defocus lens  57 . At this time, the second scanner  52  can scan the irradiation area R 1  with the laser light in the second direction (X direction) by adjusting a reflection angle of the laser light by the second motor  52   b.    
     —Intermediate Deflection Section  55 — 
     As illustrated in  FIGS.  14 ,  15 , and  16   , the intermediate deflection section  55  includes an intermediate mirror  55   a  that relays laser light between the second mirror  52   a  and the first mirror  51   a , and a pedestal  55   b  that supports the intermediate mirror  55   a . Both the intermediate mirror  55   a  and the pedestal  55   b  are accommodated in the mirror accommodation section H 11 . 
     The intermediate mirror  55   a  is configured using, for example, a total reflection mirror. The intermediate mirror  55   a  allows laser light reflected by the second mirror  52   a  to enter and reflects the laser light toward the first mirror  51   a.    
     The intermediate mirror  55   a  is also arranged to be arranged side by side with the second mirror  52   a  along the Z direction, and is located on the +Z side of the second mirror  52   a . The intermediate mirror  55   a  is further arranged to be arranged side by side with the first mirror  51   a  along the Y direction, and is located on the −Y side of the first mirror  51   a.    
     The intermediate mirror  55   a  receives laser light reflected by the second mirror  52   a  and propagating toward the +Z side, and reflects the laser light toward the +Y side. The laser light reflected by the intermediate mirror  55   a  reaches the first mirror  51   a  of the first scanner  51 . 
     The pedestal  55   b  is arranged at the bottom of the first casing  50  and supports the intermediate mirror  55   a  from the +Z side. The pedestal  55   b  according to this embodiment supports the intermediate mirror  55   a  so as to direct a mirror surface toward the +Y side and the −Z side. 
     —First Scanner  51 — 
     As illustrated in  FIGS.  14 ,  15 , and  16   , the first scanner  51  includes the first mirror  51   a  that scans laser light in the predetermined first direction, and the first motor  51   b  that rotatably supports the first mirror  51   a . Among them, the first mirror  51   a  is accommodated in the mirror accommodation section H 11 , and most of the first motor  51   b  is accommodated in the board accommodation section H 13 . 
     The first mirror  51   a  is configured as a so-called galvanometer mirror. The first mirror  51   a  receives laser light reflected by the intermediate mirror  55   a . The first mirror  51   a  reflects the received laser light toward the +Z side to deflect the laser light. As the first mirror  51   a  rotates, an irradiation position of the laser light in the irradiation area R 1  is scanned in the first direction. 
     Here, the first direction that is the deflection direction by the first mirror  51   a  is a direction orthogonal to both the above-described second direction and the Z direction as the irradiation direction as illustrated in  FIGS.  14  and  15   , and is set to coincide with the Y direction in this embodiment. 
     Note that the first direction and the second direction are not limited to the settings of this embodiment. The first direction may coincide with the X direction and the second direction may coincide with the Y direction, or the first direction and the second direction may be inclined with respect to the X direction and the Y direction, respectively. 
     Specifically, the first mirror  51   a  is a total reflection mirror having a substantially rectangular plate shape, and is accommodated in the mirror accommodation section H 11  in a state of being supported by a distal end of a rotation axis of the first motor  51   b . The first mirror  51   a  rotates integrally with a shaft of the first motor  51   b , and is configured to be rotated about the predetermined first rotation axis Ac 1  by the first motor  51   b . The amount of deflection by the first mirror  51   a  and an irradiation position of laser light in the first direction are determined based on a rotation angle of the first mirror  51   a  about the second rotation axis Ac 2 . 
     Here, the first rotation axis Ac 1 , which is a rotation center of the first mirror  51   a , extends to be orthogonal to both the second rotation axis Ac 2 , which is a rotation center of the second mirror  52   a , and the −Z direction as the irradiation direction, and is set to extend along the X direction in this embodiment. 
     With this setting, both the first rotation axis Ac and the second rotation axis Ac 2  extend in a direction different from the irradiation direction, for example, the direction (X or Y direction) orthogonal to the irradiation direction. Note that a configuration in which the first rotation axis Ac and the second rotation axis Ac 2  are orthogonal to the irradiation direction is not essential, and an inclination angle within, for example, 20 degrees with respect to the X or Y direction may be provided. 
     In addition, the first rotation axis Ac is offset to the +Z side with respect to the second rotation axis Ac 2  in this embodiment, but the first rotation axis Ac and the second rotation axis Ac 2  can be arranged on the same plane depending on the configuration of the intermediate mirror  55   a.    
     The first mirror  51   a  is also arranged side by side with the intermediate mirror  55   a  along the Y direction, and is located on the +Y side of the intermediate mirror  55   a . The first mirror  51   a  is further arranged side by side with the cover glass  62  and the defocus lens  57  along the Z direction, and is located on the −Z side of the defocus lens  57 . As a result of such a configuration, the first mirror  51   a  according to this embodiment is arranged to face the workpiece W and the irradiation area R 1  with the exit window  6  interposed therebetween. The first mirror  51   a  is located immediately above the exit window  6 , and another reflection mirror is not interposed between the first mirror  51   a  and the exit window  6 . Although the first mirror  51   a  is defined on the assumption that no reflection mirror is interposed between the first mirror  51   a  and the exit window  6  in this embodiment for convenience of the description, it is not excluded that a certain reflection mirror is interposed between the first mirror and the exit window  6 . In a case where the reflection mirror is interposed between the first mirror  51   a  and the exit window  6 , a mirror that scans an irradiation position in the irradiation area R 1  immediately before reaching the irradiation area R 1  is regarded as the first mirror  51   a . Note that an area through which laser light passes spreads between the first mirror  51   a  and the exit window  6  due to the rotation of the second mirror  52   a  and the rotation of the first mirror  51   a , and thus, the interposed reflection mirror has a size enough to cover the area through which the laser light passes. Therefore, it is preferable that the reflection mirror not be interposed between the first mirror  51   a  and the exit window  6  in order to downsize the marker head  1 . 
     The first motor  51   b  is a galvano motor configured using a DC motor or the like, and is formed in a substantially cylindrical shape with the first rotation axis Ac as a central axis. The distal end (−X-side end) of the first motor  51   b  in a direction of the first rotation axis Ac (X direction) is inserted into the seventh through-hole  50   d  of the first casing  50 . On the other hand, the other end (+Y-side end of the first motor  51   b ) located on an opposite side of the distal end in the direction of the first rotation axis Ac protrudes from the seventh through-hole  50   d  and is exposed inside the board accommodation section H 13 . 
     The first scanner  51  reflects laser light through the first mirror  51   a . The laser light reflected by the first mirror  51   a  passes through the defocus lens  57  and is emitted from the exit window  6 . At this time, the first scanner  51  can scan the irradiation area R 1  with the laser light in the first direction (Y direction) by adjusting a reflection angle of the laser light by the first motor  51   b.    
     —Defocus Lens  57 — 
     The defocus lens  57  is configured to transmit laser light deflected by the first mirror  51   a  and diffuse the laser light in an outward direction orthogonal to the irradiation direction. When the Z direction is the irradiation direction as in this embodiment, the outward direction as a diffusion direction is a direction along the XY plane. 
     Specifically, the defocus lens  57  can include, for example, one biconcave lens. In this case, the defocus lens  57  is fitted in the fifth through-hole  50   b  with its central axis along the Z direction. 
     The defocus lens  57  is also arranged in a straight line connecting the first mirror  51   a  and a central portion of the cover glass  62  in the exit window  6 . The defocus lens  57  is arranged between the first mirror  51   a  and the cover glass  62  (in other words, on the +Z side of the first mirror  51   a  and on the −Z side of the cover glass  62 ) in the Z direction. 
     The defocus lens  57  is further arranged such that an optical axis of the defocus lens  57  is coaxial with the optical axis of the cover glass  62 . Hereinafter, the optical axes of the defocus lens  57  and the cover glass  62  are collectively referred to as a “laser emission axis”, which is denoted by reference sign A 1  (see also  FIG.  4   ). The laser emission axis A 1  is configured to extend along the Z direction and is offset toward the +Y side with respect to the second mirror  52   a  and the intermediate mirror  55   a , and to cross a mirror surface of the first mirror  51   a.    
     Note that the configuration of the defocus lens  57  as the optical element is not limited to what uses one biconcave lens. The optical element may be configured using a plurality of lenses, or the optical element may be configured using a lens other than the biconcave lens. In addition, in the first place, the laser light scanning section  5  may be configured without using the defocus lens  57 . 
     —Second Control Board  54 — 
     The second control board  54  is electrically connected to the marker controller  100  and the second scanner  52 , and is configured to control the second scanner  52 . More specifically, the second control board  54  can control a rotation angle of the second mirror  52   a  by driving the second motor  52   b  in accordance with a control signal input from the marker controller  100 . 
     The second control board  54  according to this embodiment is configured using a circuit board having a substantially rectangular thin plate shape. The second control board  54  is accommodated in the board accommodation section H 13  in a posture with both front and back surfaces extending along the Z direction and the X direction, and is fastened to, for example, the vertical side portion  17   a  of the third base plate  17  from the −Y side. 
     As illustrated in  FIG.  12   , the second control board  54  is arranged on the +X side of the light source control board  24  in the X direction, and is arranged on the −Y side of the first casing  50  and the light source control board  24  in the Y direction. The second control board  54  is also electrically connected to the second motor  52   b  by wiring (not illustrated). 
     —First Control Board  53 — 
     The first control board  53  is electrically connected to the marker controller  100  and the first scanner  51 , and is configured to control the first scanner  51 . More specifically, the first control board  53  can control a rotation angle of the first mirror  51   a  by driving the first motor  51   b  in accordance with a control signal input from the marker controller  100 . 
     The first control board  53  according to this embodiment is configured using a circuit board having a substantially rectangular thin plate shape. The first control board  53  is accommodated in the board accommodation section H 13  in a posture with both front and back surfaces extending along the Z direction and the X direction, and is fastened to, for example, the vertical side portion  17   a  of the third base plate  17  from the −Y side. 
     As illustrated in  FIG.  12   , the first control board  53  is also arranged side by side with the second control board  54  along the X direction, and is located on the +X side of the light source control board  24  and the second control board  54 . The first control board  53  is also electrically connected to the first motor  51   b  by wiring (not illustrated). 
     &lt;Main Operation and Main Processing of Laser Processing Apparatus L&gt; 
       FIG.  19    is a flowchart illustrating a basic control process of the laser processing apparatus L. Hereinafter, the main operation and main processing of the laser processing apparatus L will be described with reference to  FIG.  19   . 
     First, an input of the processing pattern Pp that needs to be printed on a setting plane R 2  displayed on the display section  301  is received in step S 1  of  FIG.  19   . This input is received by the reception section  101  and read by the control section  103 . The control section  103  generates print data based on the input processing pattern Pp. The print data includes a trajectory (so-called scanning line) of laser light on the workpiece W set in accordance with the processing pattern Pp. 
     In the subsequent step S 2 , the control section  103  sets a voltage (supply voltage) that needs to be supplied to the excitation light source  21 . Details of this setting will be described later with reference to  FIGS.  20  and  21   . 
     In the subsequent step S 3 , the control section  103  inputs a control signal to the light source control board  24  and the like, so that electric power is supplied to the excitation light source  21 . Accordingly, excitation light is generated in the excitation light generation section  2 , and the excitation light is input to the laser light output section  4 . 
     In the subsequent step S 4 , when the control section  103  inputs a control signal to the Q-switch driver  49  and the like, the Q switch  43  is controlled to be turned on and off, so that UV laser light is pulsed. The laser light is output from the laser light output section  4  and input to the laser light scanning section  5 . 
     In the subsequent step S 5 , the control section  103  inputs a control signal to the first control board and  53 , the second control board  54 , and the like, so that two-dimensional scanning with the UV laser light is performed. The two-dimensional scanning referred to herein means that an irradiation position of laser light is moved in a two-dimensional direction, that is, the direction along the XY plane in this embodiment. Note that a shape of the workpiece W irradiated with laser light is not limited to a two-dimensional shape along the XY plane, and may be a three-dimensional shape having different positions in the Z direction (shape whose height in the Z direction changes). 
     At this time, the UV laser light deflected by the second mirror  52   a  is reflected by the intermediate mirror  55   a , and then, deflected again by the first mirror  51   a  in the laser light scanning section  5 . As illustrated in  FIGS.  10  and  18   , the UV laser light deflected by the first mirror  51   a  sequentially passes through the defocus lens  57  and the cover glass  62 , and then, passes through the above-described optical path defining section H 3 , thereby being emitted to the outside of the housing  10 . The UV laser light emitted to the outside of the housing  10  is emitted to the irradiation area R 1  set on the workpiece W. The UV laser light emitted onto the workpiece W is two-dimensionally scanned in the irradiation area R 1  so as to trace the scanning line according to the printing data. 
     &lt;Countermeasure against Heat Generation in Excitation Light Source  21 &gt; 
       FIG.  20    is a block diagram for describing a circuit structure according to the power supply section  104 , and  FIG.  21    is a flowchart illustrating a control process according to the power supply section  104 . As described so far, the excitation light source  21  is configured to be supplied with electric power from the power supply section  104  as the power supplier. 
     Specifically, the power supply section  104  according to this embodiment includes: a DC power supply  104   a  that converts AC power supplied from the outside into DC power and outputs the DC power; and a DC/DC converter  104   b  that performs DC/DC conversion on the power output from the DC power supply  104   a  as illustrated in  FIG.  20   . The power (particularly, DC power) converted by the DC/DC converter  104   b  is input to the excitation light source  21  configured using an LD. 
     Here, a relay  25  is interposed between the DC/DC converter  104   b  and the excitation light source  21 . The relay  25  opens and closes an electrical contact between the DC/DC converter  104   b  and the excitation light source  21 . 
     The relay  25  can be configured using, for example, a field effect transistor (FET). The relay  25  according to this embodiment includes the FET, and opens and closes the electrical contact based on a control signal input from a PLC  902 , the control section  103 , or the like via the light source control board  24 . 
     Conventionally, an output voltage input from the DC/DC converter  104   b  to the excitation light source  21  by relaying has a fixed value. Further, a variation in a forward voltage (so-called Vf) of the excitation light source  21  causes heat generation in the relay  25 . Note that a cause of the variation in Vf is, for example, a variation in quality of the excitation light source  21  itself, and Vf required for the output of certain laser light is different. Therefore, in order to secure the minimum output of the laser light even in the worst case, it is necessary to provide a margin to the output of the DC/DC converter  104   b  (in other words, to set the output voltage of the DC/DC converter  104   b  to be large). 
     However, in a case of using such a conventional configuration, the amount of heat generation in the relay  25  tends to increase. This leads to an increase in size of a heat generating structure, such as a heat sink, and thus, is likely to cause trouble when the excitation light source  21  is built in the marker head  1 . 
     Therefore, the control section  103  according to this embodiment controls the output voltage output from the power supply section  104  as the power supplier and input to the excitation light source  21 . Therefore, the control section  103  and the DC/DC converter  104   b  are electrically connected in this embodiment as illustrated in  FIG.  20   , and the output (the output voltage) from the DC/DC converter  104   b  is adjusted based on a control signal output from the control section  103 . 
     Furthermore, the control section  103  according to this embodiment detects a voltage drop occurring in the relay  25  and controls the output voltage based on the detected voltage drop. Specifically, the control section  103  controls the output voltage such that the detected voltage drop becomes a predetermined value. Therefore, a first monitor circuit  26  that monitors a voltage on the upstream side of the relay  25  and a second monitor circuit  27  that monitors a voltage on the downstream side of the relay  25  are provided in this embodiment as illustrated in  FIG.  20   . The control section  103  can estimate the voltage drop generated in the relay  25  by calculating a difference between the voltage monitored by the first monitor circuit  26  and the voltage monitored by the second monitor circuit  27 . 
     In addition, the “predetermined value” as a criterion for determination of the voltage drop can be set to, for example, 2.5 V in a state where 1 ampere has flowed through the excitation light source  21 . Note that the setting of the predetermined value is stored in advance in the storage section  102 , and is configured to be read by the control section  103  if necessary. 
     As described above, when the predetermined value is set to 2.5 V, the control section  103  adjusts the output voltage of the DC/DC converter  104   b  such that the voltage drop generated in the relay  25  becomes 2.5 V. With this configuration, there is no need to provide the margin to the output voltage of the DC/DC converter  104   b , and thus, the output voltage can be suppressed, and the heat generation occurring in the relay  25  can be suppressed. 
       FIG.  21    is a flowchart illustrating a control process related to the power supply section  104 . This control process may be executed, for example, in step S 2  during the control process of  FIG.  19   . 
     First, the control section  103  inputs a control signal to the relay  25  via the light source control board  24  to electrically connect the DC/DC converter  104   b  and the excitation light source  21  in step S 101  in  FIG.  21   . Further, the control section  103  inputs a control signal to the power supply section  104 , and supplies an output voltage of the DC/DC converter  104   b  to the excitation light source  21  via the relay  25 . 
     In the subsequent step S 102 , the control section  103  detects a voltage drop generated in the relay  25  based on detection signals of the first monitor circuit  26  and the second monitor circuit  27 . 
     In the subsequent step S 103 , the control section  103  determines whether or not the voltage drop detected in step S 102  coincides with the predetermined value set as described above. When the determination is NO, the control section  103  advances the control process to step S 105 , adjusts the output voltage from the DC/DC converter  104 , and returns to step S 101 . That is, the control section  103  is configured to repeat the processing according to steps S 101  to S 103  and step S 105  until the voltage drop coincides with the predetermined value. Note that the control section  103  determines whether or not the voltage drop generated in the relay  25  coincides with the predetermined value (step S 103  in  FIG.  21   ) in this embodiment, but the disclosure is not limited thereto. For example, whether or not the voltage drop falls within a certain range above and below the predetermined value may be determined. In short, the control section  103  may control the output voltage based on the detected voltage drop. 
     On the other hand, when the determination in step S 103  is YES, the control section  103  advances the control process to step S 104  and ends the adjustment of the output of the DC/DC converter  104  (output determination). In this case, the control section  103  ends the process illustrated in  FIG.  21    and advances the control process from step S 2  to step S 3  in  FIG.  19   . The same subsequent processing as described above is performed. 
     &lt;Lighting Control of Indicator  11 &gt; 
     As described above, the first lamp  11   a , the second lamp  11   b , and the third lamp  11   c  constituting the indicator  11  light up in accordance with control signals input from the marker controller  100 . For example, the first lamp  11   a  emits light when the marker head  1  is powered on. On the other hand, the second lamp  11   b  lights up in accordance with a standard requirement of UV laser light, and the third lamp  11   c  lights up in accordance with a state of the laser processing apparatus L, such as an irradiation state of the UV laser light and the presence or absence of occurrence of an error in the marker head  1 . Details of a lighting state are as illustrated in Table 1. 
     Specifically, when the key switch is in the “OFF” state (KSW: OFF), the marker controller  100  turns off all of the first lamp  11   a , the second lamp  11   b , and the third lamp  11   c.    
     When the key switch is in the “POWER ON” state (KSW: POWER ON), the marker controller  100  causes only the first lamp  11   a  to emit blue light and turns off both the second lamp  11   b  and the third lamp  11   c.    
     When the key switch is in the “LASER ON” state (LASER ON (KSW)), the marker controller  100  causes the first lamp  11   a  to emit blue light and causes the second lamp  11   b  to emit green light, and maintains a turn-off state of the third lamp  11   c.    
     When the marker head  1  is ready to emit UV laser light (ready state), the marker controller  100  causes the first lamp  11   a  to emit blue light and causes both the second lamp  11   b  and the third lamp  11   c  to emit green light. 
     While the UV laser light is being emitted from the marker head  1  (during laser irradiation), the marker controller  100  causes the first lamp  11   a  to emit blue light, causes the second lamp  11   b  to emit yellow light, and causes the third lamp  11   c  to emit green light. 
     When a warning of which the user needs to be notified occurs in the laser processing apparatus L (occurrence of a warning error), the marker controller  100  causes the first lamp  11   a  to emit blue light, causes the second lamp  11   b  to emit green light, and causes the third lamp  11   c  to emit orange light. 
     When any abnormality occurs in the laser processing apparatus L (occurrence of an abnormality error), the marker controller  100  causes the first lamp  11   a  to emit blue light, causes the second lamp  11   b  to emit green light, and causes the third lamp  11   c  to emit red light. 
     When the laser processing apparatus L is in an interlock state (for example, when a safety terminal block is in an off state), the marker controller  100  causes the first lamp  11   a  to emit blue light, turns off the second lamp  11   b , and causes the third lamp  11   c  to emit red light. 
     In this manner, the user can intuitively and visually recognize a state of the laser processing apparatus L by controlling a lighting state of the indicator  11  provided on the front surface  10   f  of the housing  10 . 
     
       
         
           
               
               
             
               
                   
                 TABLE 1 
               
             
            
               
                   
                   
               
               
                   
                 Indicator 
               
            
           
           
               
               
               
               
            
               
                 State 
                 First lamp 
                 Second lamp 
                 Third lamp 
               
               
                   
               
               
                 KSW: OFF 
                 Off 
                 Off 
                 Off 
               
               
                 KSW: POWER ON 
                 Blue 
                 Off 
                 Off 
               
               
                 KSW: LASER ON 
                 Blue 
                 Green 
                 Off 
               
               
                 Ready state 
                 Blue 
                 Green 
                 Green 
               
               
                 During laser 
                 Blue 
                 Orange 
                 Green 
               
               
                 irradiation 
               
               
                 Occurrence of 
                 Blue 
                 Green 
                 Orange 
               
               
                 warning error 
               
               
                 Occurrence of 
                 Blue 
                 Green 
                 Red 
               
               
                 abnormality error 
               
               
                 Interlock state 
                 Blue 
                 Off 
                 Red 
               
               
                   
               
            
           
         
       
     
     &lt;Settings of Processing Equipment  500  and Marker Head  1 &gt; 
       FIG.  18    is a diagram for describing various dimensions of the marker head  1  and the support member  501 . As illustrated in  FIGS.  17 A and  17 B , the marker head  1  is attached to the support member  501  of the processing equipment  500  by being replaced with the printing apparatus  1001  such as a TTO. The marker head  1  attached to the support member  501  irradiates the workpiece W made of a sheet-like film with UV laser light to cause a chemical reaction in a UV-reactive layer contained in the workpiece W, thereby executing printing on the workpiece W. 
     The processing equipment  500  and the marker head  1  according to this embodiment are set to be suitable for such a use mode. Hereinafter, settings related to the processing equipment  500  and the marker head  1 , and a relative positional relationship between the processing equipment  500  and the marker head  1  will be described in order. 
     First, the processing equipment  500  according to this embodiment includes the first driven roller  504   l  which is arranged on the +Y side of the conveyance roller  502  and around which the workpiece W is placed from the +Z side, and the second driven roller  504   r  which is arranged on the −Y side of the conveyance roller  502  and around which the workpiece W is placed from the −Z side, in addition to the conveyance roller  502  driven to convey the workpiece W. 
     The conveyance roller  504  as a driving roller conveys the workpiece W at a speed of 1500 mm/s or more and 2000 mm/s or less along the Y direction as a conveyance direction At. The workpiece W conveyed by the conveyance roller  504  moves along a movement path defined by the conveyance roller  502 , the first driven roller  504   l , and the second driven roller  504   r.    
     Here, a path corresponding to the irradiation area R 1  out of the movement path of the workpiece W includes a site having a different distance from the exit window  6 . That is, the movement path of the workpiece W is configured to have a different height within a range of the irradiation area R 1  as illustrated in  FIG.  18   . 
     In addition, the first driven roller  504   l  as a roller, which is immediately above the conveyance roller  502  and is the closest to the conveyance roller  502  among rollers in contact with the workpiece W on the upstream side of the conveyance roller in the movement path of the workpiece W, and the second driven roller  504   r  as a roller, which is immediately below the conveyance roller  502  and is the closest to the conveyance roller  502  among the rollers in contact with the workpiece W at the downstream side of the conveyance roller, are all driven rollers that rotate as the workpiece W is conveyed. The roller immediately above the conveyance roller  502  and the roller immediately below the conveyance roller are not limited to the driven rollers, but are preferably rollers in which the amount of sliding of the workpiece W with respect to the conveyance roller  502  is large even when being driven by a separately provided drive source. For example, if a material has a large frictional force with respect to the workpiece W, the amount of sliding is small. In addition, in a case where the surfaces of the respective rollers are made of the same material, the amount of slip is smaller as the amount of contact with the workpiece W is larger. In a case where the immediately upper roller and the immediately lower roller are configured using driven rollers or rollers having a large amount of slip with respect to the conveyance roller  502 , an error hardly occurs in the amount of movement of the workpiece W with respect to the rotation of the conveyance roller  502 . Therefore, the print quality can be improved by performing print control based on the rotation of the conveyance roller  502 . In particular, the marker head  1  of this embodiment performs printing on the workpiece W in a non-contact manner as compared with the TTO, and thus, a printing position is likely to deviate when the slip occurs in the conveyance roller  502 . Therefore, the marker head  1  is preferably arranged in the irradiation area R 1  such that the conveyance roller having a small amount of slip with respect to rollers immediately before and immediately after the irradiation area R 1  is located. 
     Here, an area irradiated with UV laser light corresponding to the irradiation area R 1  out of the movement path of the workpiece W is arranged to be separated farther from the cover glass  62  as the optical member than an end of the second accommodation section H 2  in a protruding direction, in the protruding direction of the second accommodation section H 2 . 
     Here, the protruding direction of the second accommodation section H 2  coincides with the irradiation direction (that is, the +Z direction) of the UV laser light in this embodiment. In addition, the end of the second accommodation section H 2  in the protruding direction corresponds to a +Z-side end of the housing  10  in this embodiment. 
     That is, the area irradiated with the UV laser light in the movement path of the workpiece W is arranged on the +Z side of the +Z-side end of the housing  10 . In other words, the area irradiated with the UV laser light in the movement path of the workpiece W does not enter the optical path defining section H 3  (is arranged on the +Z side of the optical path defining section H 3 ). According to this configuration, the workpiece W can be easily inserted into the movement path from the front side of the movement path of the workpiece W. Therefore, it is easy to set the workpiece W to the movement path. 
     In addition, an apex  502   a  of the conveyance roller  502  on the cover glass  62  side (−Z side) is offset to the upstream side (+Y side) or the downstream side (−Y side) in the conveyance direction At substantially coinciding with the Y direction with respect to a center line (the laser emission axis A 1 ) penetrating the central portion of the cover glass  62  (offset to +Y side in the illustrated example) as illustrated in  FIG.  18   . 
     That is, a center line Ar passing through the rotation axis of the conveyance roller  502  and extending in the Z direction is offset to the upstream side or the downstream side with respect to the laser emission axis A 1 . In other words, the laser emission axis A 1  extending in the Z direction and the rotation axis of the conveyance roller  502  extending in the X direction are laid out so as not to cross each other. 
     In addition, in other words, the laser emission axis A 1  is offset to the upstream side (+Y side) or the downstream side (−Y side) in the conveyance direction At with respect to the apex  502   a  (offset to the −Y side in the illustrated example). Specifically, out of the workpiece W on the upstream side and the workpiece W on the downstream side with respect to the apex  502   a  as illustrated in  FIG.  18   , the latter workpiece W has a smaller inclination with respect to a plane (the XY plane) orthogonal to the laser emission axis A 1 . That is, the workpiece W on the downstream side with respect to the apex  502   a  is inclined more gently than the workpiece W on the upstream side. The laser emission axis A 1  according to this embodiment is offset to a side where the inclination of the workpiece W with respect to the plane orthogonal to the laser emission axis A 1  is smaller, such as the workpiece W on the downstream side, out of the upstream side and the downstream side in the conveyance direction At. 
     Note that a size of the irradiation area R 1  is set to be larger than a printable area (print area) in the printing apparatus  1001  before the replacement configured as the TTO. The TTO brings the printing section  1006  extending in the lateral direction of the workpiece W into contact with the workpiece W to perform printing on the workpiece W. Therefore, even if a printing area on the workpiece W is an area having a certain length in the longitudinal direction of the workpiece W, printing can be performed on the entire printing area on the workpiece W by causing the workpiece W to pass through the printing section  1006  if there is a positional relationship in which the printable range of the printing section  1006  includes the printing area on the workpiece W in the lateral direction of the workpiece W. On the other hand, a portion irradiated with laser light at a certain moment in the marker head  1  has a certain area but has a point shape. Therefore, when the printing area on the workpiece W is the area having a certain length in the longitudinal direction of the workpiece W, the irradiation area R 1  irradiated with the laser light preferably has a certain length (dimension) in a direction corresponding to the longitudinal direction of the workpiece W. Specifically, a dimension (see reference sign L 5  in  FIG.  17 A ) of the irradiation area R 1  in the conveyance direction At is set to be 120 mm or more when the workpiece W is parallel to the XY plane. Note that the irradiation area R 1  in this embodiment indicates an area that can be irradiated with the laser light by the first scanner  51  and the second scanner  52  on the surface of the workpiece W. 
     In addition, a size of the irradiation area R 1  when the workpiece W is parallel to the XY plane is set such that the irradiation area R 1  is covered with the bottom surface  10   d  of the housing  10  in the XY plane. That is, the entire irradiation area R 1  overlaps the bottom surface  10   d  as viewed in the Z direction orthogonal to the XY plane, the dimension L 5  of the irradiation area R 1  in the Y direction is smaller than a dimension of the bottom surface  10   d  of the housing  10  in the Y direction, and a dimension L 6  of the irradiation area R 1  in the X direction is smaller than a dimension of the housing  10  in the X direction. According to this configuration, the laser light with which the workpiece W is irradiated is less likely to leak to the surroundings. In particular, when a distance from the +Z-side end of the housing  10  to the workpiece W (see a distance L 2  in  FIG.  18   ) is set to 0 mm or more and 20 mm or less, the leakage of the laser light is reduced. Further, when the workpiece W is a sheet-like workpiece W placed around a plurality of conveyance rollers and conveyed, the user can easily set the workpiece W on the movement path of the workpiece W by inserting the workpiece W from the front side of the conveyance rollers. Therefore, the work of setting the workpiece W in the movement path becomes easy when the front side of the movement path of the workpiece W is opened. Therefore, the leakage of the laser light can be reduced while maintaining the workability of setting the workpiece W by opening the front side of the movement path according to the configuration in which the entire length of the irradiation area R 1  is accommodated in the bottom surface  10   d  in the X direction. Note that, in a case of adopting the configuration in which the leakage of the laser light is reduced using a member covering the front side of the workpiece W, there is a possibility that the workpiece W comes into contact with the member so that the workpiece W is contaminated when the workpiece W is moved obliquely, and thus, the possibility of contamination of the workpiece W is reduced according to the configuration in which the front side of the workpiece W is opened. 
     Note that these settings are particularly effective when eight characters are printed on the workpiece W by irradiating the workpiece W with UV laser light for 10 ms per character in a square of 3 mm×2 mm. Here, a parameter related to the UV laser light is suitable for a case where a line width (corresponding to target line width of 100 to 150 μm for one scanning line) of 0.2 to 0.35 mm is achieved by boldface printing with three scanning lines. 
     When the irradiation area R 1  is set to be larger than the printable area in the TTO, printing can be performed in the irradiation area R 1  while causing an irradiation position of the UV laser light to follow the conveyance of the workpiece W. Accordingly, the printable area similar to that in the TTO can be secured. 
     On the other hand, an output of the laser light generated by the marker head  1  and passing through the exit window  6  is set to 1 W or more and 2 W or less. This setting is determined to achieve the downsizing of the marker head  1 . Color development in printing when laser light is emitted for a certain period of time varies depending on a power density of the emitted laser light. When the output of the laser light is 1 W or more and 2 W or less, a spot diameter of the laser light is preferably 160 μm or less such that sufficient color development can be obtained. 
     More preferably, a spot diameter of the laser light in the irradiation area R 1  is set to 60 μm or more and 80 μm or less. This spot diameter can be set such that a depth of focus of the laser light corresponds to a portion having the longest optical path length of the laser light in the irradiation area R 1  (an end of the irradiation area R 1 ) and a portion having the shortest optical path length in the irradiation area R 1  (a central portion of the irradiation area R 1 ). 
     For example, a lower limit value of the spot diameter is a setting that corresponds to the number of scanning lines and the line width described above. In this setting, in a case where the dimension of the irradiation area R 1  is set to 120 mm or more when the distance from the +Z-side end of the housing  10  to the workpiece W (see the distance L 2  in  FIG.  18   ) is set to 0 mm or more and 20 mm or less, it is advantageous in terms of suppressing an influence of an optical path length difference between the central portion and the end of the irradiation area R 1  without adjusting the focus along the Z direction. 
     On the other hand, an upper limit value of the spot diameter is advantageous when boldface printing is performed with a thickness of 200 μm (0.2 mm) or more, such as the above-described line width of 0.2 to 0.35 mm. In this case, there is a concern that a processing time required for boldface processing becomes relatively long, but the irradiation area R 1  of the UV laser light can be made large by setting the upper limit value of the spot diameter as described above, and time for which the irradiation is possible can be made long. 
     Note that the upper limit value (=80 μm) of the spot diameter is an optimum value in a case where the UV laser light is emitted in parallel with the irradiation direction and the distance L 2  is set to 10 mm. When the distance L 2  is changed within the range of 0 mm or more and 20 mm or less, the upper limit value of the spot diameter is 120 μm. 
     Note that, when there is a concern about the optical path length difference in the irradiation area R 1 , the depth of focus can be made deeper by providing the defocus lens  57  described above. To make the depth of focus deeper is advantageous in terms of suppressing the influence of the optical path length difference. 
     In addition, among relative positions of the workpiece W with respect to the housing  10 , particularly, a relative position where printing can be performed with respect to the workpiece W is set such that a distance (particularly, distance as viewed along the irradiation direction, and corresponds to the sum of the distance L 2  and a distance L 3  in  FIG.  19   ) from the first mirror  51   a  to the surface of the workpiece W is 150 mm or less. 
     Note that the distance from the top surface  10   u  of the housing  10  to the workpiece W is set to be 195 mm or less in this embodiment, in addition to the above. The TTO as the printing apparatus  1001  before replacement is often used in an environment where the distance from the top surface to the workpiece W is around 200 mm, and can be used in an environment similar to that of the printing apparatus  1001  before replacement. Specifically, a distance L 1  from the top surface  10   u  of the housing  10  to the +Z-side end of the bottom surface  10   d  is set to 165 mm in this embodiment. Further, the distance L 2  from the +Z-side end of the bottom surface  10   d  to the workpiece W is preferably set to 30 mm or less, and more preferably 20 mm or less. 
     Here, when the distance L 2  is set to 30 mm or less, regular reflection light by the workpiece W of laser light with which the irradiation area R 1  is irradiated can be guided to an area between the first plate-shaped member  181  and the second plate-shaped member  18   r , that is, to the optical path defining section H 3 . This is advantageous in terms of suppressing leakage of the regular reflection light to the outside of the housing  10 . 
     In addition, the distance L 3  from the first mirror  51   a  to the +Z-side end of the bottom surface  10   d  is set to 123 mm in this embodiment. Further, a distance L 4  from a lower surface of the defocus lens  57  to the +Z-side end of the bottom surface  10   d  is set to 100 mm. Here, considering that a thickness of the defocus lens  57  is 2 mm, a distance (not illustrated) from an upper surface of the defocus lens  57  to the +Z-side end of the bottom surface  10   d  is set to 102 mm. 
     Here, a distance (=L 1 −L 3 ) from the top surface  10   u  to the first mirror  51   a  is 42 mm, and a distance (=L 1 −L 4 ) from the top surface  10   u  to the defocus lens  57  is 65 mm. On the other hand, the central portion of the housing  10  in the Z direction corresponds to a site of about 82 mm (=L 1 /2) as viewed from the top surface  10   u . Therefore, both the first mirror  51   a  and the defocus lens  57  according to this embodiment are located on the −Z side of the central portion of the housing  10  in the Z direction. 
     &lt;Positional Relationship among Housing  10 , Support Member  501 , and Workpiece W&gt; 
     As described above, the attachment surface of the housing  10  is formed on an opposite side of the exit window  6  according to this embodiment (see the lower diagram of  FIG.  17 A ). In the housing  10 , not the bottom surface  10   d  on which the exit window  6  is formed, but the top surface  10   u  facing the opposite side thereof is configured to be attached to an attachment target position as the attachment surface, so that the housing  10  can be supported to be suspended from the attachment target position. This eliminates the need for interposing the support member  501  between the housing  10  and the workpiece W, and thus, the housing  10  and the workpiece W can be brought close to each other. 
     At this time, the support member  501  for supporting the housing  10  is located on the opposite side of the exit window  6  similarly to the attachment target position, and thus, can be sufficiently separated from the workpiece W. This makes it possible to suppress the interference between the support member  501  and the workpiece W while bringing the housing  10  and the workpiece W close to each other. 
     In addition, a gap is provided between the first base plate  15  and the top surface  10   u  as the attachment surface as illustrated in  FIGS.  10 ,  13   , and the like, so that it is possible to suppress the solid-state laser crystal  41  from being affected by the influence of distortion, vibration, and the like generated on the attachment surface at the attachment target position. As a result, the laser light can be favorably generated even in a case where the housing  10  is configured to be supported at the attachment target position. 
     In addition, the support member  501  and the attachment surface are configured to be connected via the attachment  7  instead of being directly connected as illustrated in  FIG.  17 A  and the like, so that the housing  10  can be attached to the support member  501  that can take various forms without devising a structure of the housing  10  itself. This is advantageous in terms of facilitating replacement of various processing apparatuses with the laser processing apparatus L according to the disclosure. 
     In addition, the front surface  10   f  as the open surface is configured to be openable and closable as illustrated in  FIGS.  3 A and  3 B  and the like, instead of the exit surface (that is, the bottom surface  10   d ) facing the workpiece W and the attachment surface (that is, the top surface  10   u ) attached to the attachment target position, so that the exit window  6  can be accessed without causing interference with the workpiece W, the support member  501 , and the like. As a result, maintainability of the laser processing apparatus L can be improved. 
     In addition, since the front surface  10   f  as the open surface on which the cover member  13  is provided and the back surface  10   b  as the connection surface to which the electric cable  200  is connected are located on the opposite sides as illustrated in  FIG.  4    and the like, the interference between the cover member  13  and the electric cable  200  is suppressed at the time of opening, closing, attaching, or detaching the cover member  13 . As a result, maintainability of the laser processing apparatus L can be improved. 
     OTHER EMBODIMENTS 
     Although the second accommodation section H 2  is formed in the housing  10  in the above embodiment, the second accommodation section H 2  is not essential. For example, the first heat sink  81  and the second heat sink  82  may be accommodated in the first accommodation section H 1 . In addition, the optical path defining section H 3  can also be omitted as appropriate. 
     In addition, the excitation light source  21  is accommodated in the housing  10  of the marker head  1  in the above embodiment, but the disclosure is not limited to such a configuration. For example, the excitation light source  21  may be provided in the marker controller  100 . 
     In addition, the crystal accommodation section H 12 , the mirror accommodation section H 11 , and the board accommodation section H 13 , obtained by dividing the first accommodation section H 1  in the housing  10  into three portions, are arranged side by side in this order along the Y direction orthogonal to the irradiation direction in the above embodiment, but the disclosure is not limited to such a configuration. For example, the arrangement order of the crystal accommodation section H 12 , the mirror accommodation section H 11 , and the board accommodation section H 13  may be changed, or any two of the crystal accommodation section H 12 , the mirror accommodation section H 11 , and the board accommodation section H 13  may be arranged side by side along the irradiation direction. 
     In addition, the top surface  10   u  facing the bottom surface  10   d  on which the exit window  6  is formed among the six surfaces of the housing  10  is set as the attachment surface in the above embodiment, but the disclosure is not limited to such a setting. Any one surface among the six surfaces excluding the bottom surface  10   d  on which the exit window  6  is formed can be regarded as the attachment surface. For example, in a case where the right side surface  10   r  is the attachment surface, the support member  501  supports the housing  10  to be supported from the left side. 
     In addition, among the six surfaces of the housing  10 , two or more surfaces excluding the bottom surface  10   d  can be regarded as the attachment surfaces. For example, in a case where the left side surface  101  and the top surface  10   u  are the attachment surfaces, the attachment  7  may be attached to one of the left side surface  101  and the top surface  10   u , or may be attached to both the left side surface  101  and the top surface  10   u  as in a marker head  1 ′ illustrated in  FIG.  22   . 
     For example, an attachment  2007  illustrated in  FIG.  22    has a first portion  2007   a  attached to the top surface  10   u  and a second portion  2007   b  attached to the left side surface  101 , and a support member  501 ′ also has a shape conforming to the attachment  2007 . In this manner, the attachment surface can be set in accordance with a form of the support member  501 ′, and the attachment  2007  corresponding to this setting can be used. 
     In addition, the attachment  7  is not essential in the first place. As in a housing  10 ″ of a marker head  1 ″ illustrated in  FIG.  23   , the support member  501  can also be directly attached to an attachment surface (a top surface  10   u ″ in the illustrated example) without the intervention of the attachment  7 . In this case, a partial area of the attachment surface may be regarded as an attachment. In addition, a part of the attachment surface may protrude in a direction opposite to the exit window  6 , and such a protrusion may be used as the attachment.