Patent Publication Number: US-2019179102-A1

Title: Three-dimensional shaping apparatus, control method of three-dimensional shaping apparatus, and control program of three-dimensional shaping apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based upon and claims the benefit of priority from Japanese patent application No. 2017-235355, filed on Dec. 7, 2017, the disclosure of which is incorporated herein in its entirety by reference. 
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a three-dimensional shaping apparatus, a control method of the three-dimensional shaping apparatus, and a control program of the three-dimensional shaping apparatus. 
     Description of the Related An 
     In the above technical field, patent literature 1 discloses a technique of providing a condenser lens in an irradiator. 
     [Patent Literature 1] Japanese Patent Laid-Open No. 8-230048 
     SUMMARY OF THE INVENTION 
     In the technique described in the above literature, however, it is impossible to select attachment of a lens unit, thereby making it impossible to implement large-size shaping and small-size high-resolution shaping by one apparatus. 
     The present invention enables to provide a technique of solving the above-described problem. 
     One example aspect of the present invention provides a three-dimensional shaping apparatus comprising: 
     an attachment mechanism that attaches, to a predetermined position, a lens unit that condenses a light beam from a light source; and 
     an adjustment mechanism that adjusts a position of the light source in accordance with the attached lens unit. 
     Another example aspect of the present invention provides a control method of a three-dimensional shaping apparatus including 
     an attachment mechanism that attaches, to a predetermined position, a lens unit that condenses a light beam from a light source, and 
     an adjustment mechanism that adjusts a position of the light source in accordance with the attached lens unit, 
     the attachment mechanism including a moving mechanism that can move the lens unit between an attachment position of the lens unit and a non-attachment position of the lens unit, 
     the method comprising: 
     driving the moving mechanism to move between the attachment position of the lens unit and the non-attachment position of the lens unit; 
     driving the adjustment mechanism to adjust the position of the light source between a first position of the light source obtained when the lens unit is attached and a second position of the light source obtained when the lens unit is not attached; and 
     controlling the driving the moving mechanism and the driving the adjustment mechanism to synchronize with each other. 
     Still other example aspect of the present invention provides a control program of a three-dimensional shaping apparatus including 
     an attachment mechanism that attaches, to a predetermined position, a lens unit that condenses a light beam from a light source, and 
     an adjustment mechanism that adjusts a position of the light source in accordance with the attached lens unit, 
     the attachment mechanism including a moving mechanism that can move the lens unit between an attachment position of the lens unit and a non-attachment position of the lens unit, 
     the program for causing a computer to execute a method, comprising: 
     driving the moving mechanism to move between the attachment position of the lens unit and the non-attachment position of the lens unit; 
     driving the adjustment mechanism to adjust the position of the light source between a first position of the light source obtained when the lens unit is attached and a second position of the light source obtained when the lens unit is not attached; and 
     controlling the driving the moving mechanism and the driving the adjustment mechanism to synchronize with each other. 
     According to the present invention, it is possible to select attachment of a lens unit, thereby making it possible to implement large-size shaping and small-size high-resolution shaping by one apparatus. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a view showing the arrangement of the attachment mechanism of a three-dimensional shaping apparatus according to the first example embodiment of the present invention; 
         FIG. 1B  is a view showing the overall arrangement of the three-dimensional shaping apparatus according to the first example embodiment of the present invention; 
         FIG. 2A  is a view showing the overall arrangement of a three-dimensional shaping apparatus according to the second example embodiment of the present invention; 
         FIG. 2B  is a partially enlarged view showing an example of the attachment mechanism of the three-dimensional shaping apparatus according to the second example embodiment of the present invention; 
         FIG. 2C  is a partially enlarged view showing another example of the attachment mechanism of the three-dimensional shaping apparatus according to the second example embodiment of the present invention; 
         FIG. 3  is a partially enlarged view showing an example of the attachment mechanism of a three-dimensional shaping apparatus according to the third example embodiment of the present invention; 
         FIG. 4A  is a partially enlarged view showing an example of the attachment mechanism of a three-dimensional shaping apparatus according to the fourth example embodiment of the present invention; 
         FIG. 4B  is a partially enlarged view showing another example of the attachment mechanism of the three-dimensional shaping apparatus according to the fourth example embodiment of the present invention; 
         FIG. 5A  is a partially enlarged view showing an example of the attachment mechanism of a three-dimensional shaping apparatus according to the fifth example embodiment of the present invention; 
         FIG. 5B  is another partially enlarged view showing an example of the attachment mechanism of the three-dimensional shaping apparatus according to the fifth example embodiment of the present invention; 
         FIG. 6  is a table showing an example of a synchronization table provided in the three-dimensional shaping apparatus according to the fifth example embodiment of the present invention; and 
         FIG. 7  is a flowchart illustrating the operation procedure of the three-dimensional shaping apparatus according to the fifth example embodiment of the present invention. 
     
    
    
     DESCRIPTION OF THE EXAMPLE EMBODIMENTS 
     Example embodiments of the present invention will now be described in detail with reference to the drawings. It should be noted that the relative arrangement of the components, the numerical expressions and numerical values set forth in these example embodiments do not limit the scope of the present invention unless it is specifically stated otherwise. 
     First Example Embodiment 
     A three-dimensional shaping apparatus  100  according to the first example embodiment of the present invention will be described with reference to  FIGS. 1A and 1B . The three-dimensional shaping apparatus  100  is an apparatus that shapes a three-dimensional shaped object by irradiating a material of the three-dimensional shaped object with a light beam. 
     As shown in  FIGS. 1A and 1B , the three-dimensional shaping apparatus  100  includes an attachment mechanism  101 , an adjustment mechanism  102 , and a shaping unit  110 . The attachment mechanism  101  attaches, to a predetermined position, a lens unit  111  that condenses a light beam  122  from a light source  121 . The adjustment mechanism  102  adjusts the position of the light source  121  in accordance with the attached lens unit  111 . In the shaping unit  110 , the material of the three-dimensional shaped object is irradiated with the light beam  122  from the light source  121 . Then, the three-dimensional shaped object is shaped in the shaping unit  110 . 
     According to this example embodiment, it is possible to implement large-size shaping and small-size high-resolution shaping by one apparatus. 
     Second Example Embodiment 
     A three-dimensional shaping apparatus according to the second example embodiment of the present invention will be described with reference to  FIGS. 2A to 2C .  FIG. 2A  is a view showing the overall arrangement of the three-dimensional shaping apparatus according to this example embodiment.  FIG. 2B  is a partially enlarged view showing an example of the attachment mechanism of the three-dimensional shaping apparatus according to this example embodiment. 
     A three-dimensional shaping apparatus  200  includes an optical engine  201 , a column  202 , a table  203 , a material storage  204 , a platform  205 , and an attachment mechanism  206 . 
     The optical engine  201  irradiates a material of a three-dimensional shaped object with a light beam. The material of the three-dimensional shaped object is, for example, a photo-curing resin. 
     The optical engine  201  is a high-output high-resolution engine. Note that the light beam emitted from the optical engine  201  has a wavelength of 405 nm but may have a wavelength of 200 nm to 400 nm. The present invention is not limited to this. 
     Although the detailed arrangement of the optical engine  201  is not shown, the optical engine  201  includes a light source, a reflecting mirror, a photodetector, and a two-dimensional MEMS (Micro Electro Mechanical System) mirror. The light source includes a semiconductor LD (Laser Diode) and a collimator lens. The semiconductor LD is a laser beam oscillation element that oscillates an ultraviolet laser beam or the like. Note that the laser beam oscillation element is not limited to the semiconductor LD and may be an LED (Light Emitting Diode). The two-dimensional MEMS mirror is a driving mirror that is driven based on an externally input control signal, and a device that vibrates to reflect the laser beam by changing an angle in the horizontal direction (X direction) and the vertical direction (Y direction). The optical engine  201  has a resolution of 720p or 1080p, and has a width of about 30 mm, a depth of about 15 mm, a height of about 7 mm, and a volume of about 3 cc. The number of semiconductor LDs arranged in the optical engine  201  may be one or more, and a necessary number of semiconductor LDs are arranged in accordance with the application purpose. The spot size of the light beam emitted from the optical engine  201  is 75 μm but can be changed appropriately in accordance with the application purpose. 
     The table  203  is attached to the column  202 . A photosensor  231  is attached to the table  203  via a sensor supporter (sensor bracket)  232 . The position of the photosensor  231  is adjusted using a sensor adjustment stage  233 . 
     The material storage  204  is placed on the table  203 . The material of the three-dimensional shaped object is charged and stored in the material storage  204 . The bottom surface of the material storage  204  is formed by including a member capable of transmitting the light beam. The member capable of transmitting the light beam is represented by, for example, a glass member but the present invention is not limited to this. The entire material storage  204  may be formed by a member capable of transmitting the light beam. Note that the material storage  204  may be fixed to a predetermined position on the table  203  by a screw or the like, or may simply be placed on the table  203 . A method of placing the material storage  204  on the table  203  is not limited to them. 
     The platform  205  is attached to a platform support member  251  by a platform mounting screw  253 . In addition, the platform  205  is attached to the column  202  via the platform support member  251 . The platform  205  can be detached from the platform support member  251  by loosening the platform mounting screw  253 . The platform  205  can be fixed to the platform support member  251  by tightening the platform mounting screw  253 . 
     The platform  205  is used to shape a three-dimensional shaped object. The platform  205  rises and lowers by a platform feeding mechanism, a stepping motor, and the like. That is, when shaping a three-dimensional shaped object, the platform  205  is aligned and lowered to a position where it contacts the bottom surface of the material storage  204 . Then, while raising and pulling up the platform  205  from the state in which the platform  205  and the bottom surface of the material storage  204  are in contact with each other, the material is irradiated with the light beam, thereby shaping the three-dimensional shaped object. Note that the platform  205  is aligned using, for example, the photosensor  231 . The position of the platform  205  can be detected using, for example, a contact bracket (not shown) and the photosensor  231 . The position of the platform  205  can be detected in accordance with a position at which the contact bracket crosses the photosensor  231 . 
     The platform  205  rises and lowers by the platform feeding mechanism, the stepping motor, and the like. The platform feeding mechanism is, for example, a high-rigidity ball screw feeding mechanism. The stepping motor is, for example, a high-torque stepping motor. Note that a structure that raises and lowers the platform  205  is not limited to the structure that uses the platform feeding mechanism and the stepping motor. The platform feeding mechanism is not limited to the ball screw feeding mechanism. 
     The platform feeding mechanism is a high-rigidity high-speed precision feeding mechanism. The rigidity, feeding speed, and feeding pitch of the platform are, for example, 3 kgw, 50 nm/sec, and 2.5 μm, respectively. The platform  205  is light in weight. 
     The attachment mechanism  206  is a mechanism for attaching, to a predetermined position, a lens unit  207  that condenses the light beam from the optical engine  201  serving as a light source. The attachment mechanism  206  is detachable from the three-dimensional shaping apparatus  200 . As shown in the left and right views of  FIG. 2B , the attachment mechanism  206  is attached to the three-dimensional shaping apparatus  200  by being fitted in a light source holder  211  that is used to attach and hold the optical engine  201 . That is, a lens holder  261  is screwed in the light source holder  211  by screws  262 . This attaches the lens holder  261  to the three-dimensional shaping apparatus  200 . 
     The attachment mechanism  206  includes the lens holder  261  and the screws  262 . The lens unit  207  is attached in advance to the lens holder  261 . Then, the lens holder  261  attached with the lens unit  207  is attached to the light source holder  211  using the screws  262 , thereby making it possible to attach the lens unit  207  to the three-dimensional shaping apparatus  200 . In the lens holder  261 , screw holes in which threads for screwing the screws  262  are cut are formed. 
     Note that the example in which the lens unit  207  including one type of lens is attached to one lens holder  261  has been explained. However, a lens unit  207  including a plurality of types of lenses may be attached to one lens holder  261 . Alternatively, a plurality of lens holders  261  each attached with the lens unit  207  including one type of lens may be used. 
     If the lens unit  207  is attached to the three-dimensional shaping apparatus  200 , the focus position of the light beam from the optical engine  201  changes. Therefore, the position of the optical engine  201  is adjusted in accordance with the focus position of the light beam. The position of the optical engine  201  is adjusted using a setting mechanism (not shown) provided in the light source holder  211 , or the like. The setting mechanism is, for example, a mechanism for manually adjusting the position of the optical engine  201 . 
     If, for example, the lens unit  207  is attached, the position of the optical engine  201  is moved upward, closer to the table  203 . That is, since the focal length of the light beam is shortened by attaching the lens unit  207 , the position of the optical engine  201  is made closer to the table  203  to shorten the distance between the optical engine  201  and the platform  205 . 
     If no lens unit  207  is attached, for example, when the three-dimensional shaping apparatus  200  is used by detaching the attached lens holder  261 , the focal length of the light beam from the optical engine  201  is increased, and it is thus necessary to lower the position of the optical engine  201 . That is, the optical engine  201  is moved in a direction away from the table  203  to increase the distance between the optical engine  201  and the platform  205 . Note that adjustment of the position of the optical engine  201  is not limited to the described setting method. The position is adjusted in accordance with the attached lens unit  207 . The lens unit  207  attached to the lens holder  261  is a condenser lens that has a positive focal length, that is, positive refractive power. 
       FIG. 2C  is a partially enlarged view showing another example of the attachment mechanism of the three-dimensional shaping apparatus according to this example embodiment. As shown in the left view of  FIG. 2C , two shafts  264  are provided in the light source holder  211 . Note that the number of shafts  264  provided in the light source holder  211  is not limited to two, and may be one or three or more. 
     Two holes into which the shafts  264  are inserted are formed in a lens holder  263  in correspondence with the shafts  264 . The number of holes formed in the lens holder  263  corresponds to the number of shafts  264 . As shown in the right view of  FIG. 2C , the lens holder  263  is inserted into the two shafts  264  from above, thereby attaching the lens holder  263  to the light source holder  211 . The position of the optical engine  201  is adjusted in accordance with the presence/absence of attachment of the lens unit  207 . 
     A shaping size when the lens unit  207  is used is, for example, a size of 52 mm×37 mm. If the lens unit  207  is used, the three-dimensional shaping apparatus  200  can perform small-size high-resolution shaping. A shaping size when no lens unit  207  is used is, for example, a size of 142 mm×80 mm. If no lens unit  207  is used, the three-dimensional shaping apparatus  200  can perform large-size shaping. Note that the size in the case of small-size shaping and that in the case of large-size shaping are not limited to the above-described examples. The shaping size can be changed appropriately in accordance with the lens unit  207  used. 
     According to this example embodiment, since the focal length of the light beam from the optical engine  201  can be changed in accordance with the presence/absence of attachment of the lens unit  207 , shaping of a large-size three-dimensional shaped object and shaping of a small-size high-resolution three-dimensional shaped object can be performed by one three-dimensional shaping apparatus  200 . Furthermore, it is possible to attach/detach the lens unit easily. 
     Third Example Embodiment 
     A three-dimensional shaping apparatus according to the third example embodiment of the present invention will be described with reference to  FIG. 3 .  FIG. 3  is a view showing an example of the attachment arrangement of the three-dimensional shaping apparatus according to this example embodiment. The three-dimensional shaping apparatus according to this example embodiment is different from the above-described second example embodiment in that a lens unit is detachable from a lens holder. The remaining components and operations are the same as those in the second example embodiment. Hence, the same reference numerals denote the same components and operations, and a detailed description thereof will be omitted. 
     A three-dimensional shaping apparatus  300  includes an attachment mechanism  306 . A lens unit  307  is attached in a hole  362 , formed in a lens holder  361 , for attaching the lens unit  307 . The lens unit  307  is inserted (attached and stored) into the hole  362 , as shown in the left view of  FIG. 3 . In this case, in the hole  362 , a projecting portion (not shown) on which the lens unit  307  is placed, that is, a portion projecting inside on which the lens unit  307  is placed is provided. This projecting portion may be provided on the entire periphery of the hole  362  or partially provided on the periphery of the hole  362 . 
     As shown in the right view of  FIG. 3 , the lens unit  307  is placed in the hole  362 , thereby making it possible to attach the lens unit  307  to the three-dimensional shaping apparatus  300 . In this case, the lens holder  361  is attached in advance to a light source holder  211  or the like. 
     Threads may be formed in the lens unit  307  and the hole  362 , and the lens unit  307  may be screwed in the lens holder  361 . If the lens unit  307  is screwed in this way, the lens unit  307  can be fixed to the lens holder  361  reliably. A pressing ring may be screwed from above the lens unit  307 . 
     According to this example embodiment, since the lens unit is placed or screwed in the lens holder, it is possible to attach/detach the lens unit easily, and fix the lens unit to the lens holder reliably. 
     Fourth Example Embodiment 
     A three-dimensional shaping apparatus according to the fourth example embodiment of the present invention will be described with reference to  FIGS. 4A and 4B .  FIG. 4A  is a partially enlarged view showing an example of the attachment mechanism of the three-dimensional shaping apparatus according to this example embodiment. The three-dimensional shaping apparatus according to this example embodiment is different from the above-described second and third example embodiments in that a moving mechanism is provided as the attachment mechanism. The remaining components and operations are the same as those in the second example embodiment. Hence, the same reference numerals denote the same components and operations, and a detailed description thereof will be omitted. 
     A three-dimensional shaping apparatus  400  includes a moving mechanism  406  as an attachment mechanism that attaches a lens unit  407  to a predetermined position. The moving mechanism  406  includes a rotating mechanism that rotates the attachment mechanism about a predetermined shaft. The moving mechanism  406  includes a lens holder  461 , and the lens holder  461  is attached with the lens unit  407 . The lens holder  461  rotates about a rotating shaft  481  in accordance with movement of a motor  408 . This allows the lens unit  407  to move between an attachment position and a non-attachment position. 
     Since the lens holder  461  rotates about the rotating shaft  481 , the lens unit  407  moves to the attachment position of the lens unit  407 , that is, onto the path of a light beam from an optical engine  201 , as shown in the left view of  FIG. 4A . As shown in the right view of  FIG. 4A , the lens unit  407  moves to the non-attachment position of the lens unit  407 , that is, a position (a position where no light beam is blocked) away from the path of the light beam from the optical engine  201 , as shown in the right view of  FIG. 4A . With the moving mechanism  406 , the lens unit  407  can be automatically attached or released (detached). Note that the example of moving the lens holder  461  by the motor  408  has been explained. However, the lens holder  461  may be rotated and moved manually, instead of using the motor  408 . 
       FIG. 4B  is a partially enlarged view showing another example of the attachment mechanism of the three-dimensional shaping apparatus according to this example embodiment. The three-dimensional shaping apparatus  400  includes the moving mechanism  406  including a slide mechanism. The slide mechanism includes a lens holder  462 . The lens unit  407  is attached to the lens holder  462 , and slides by the slide mechanism. A gear  482  is attached to the rotating shaft of the motor  408  so that the gear  482  meshes with a groove (rack)  483  provided in the lens holder  462 . Therefore, the lens holder  462  slides in accordance with the movement of the gear  482 . Note that the groove  483  is formed on one inner side of the lens holder  462 . 
     If the motor  408  is rotated, the lens holder  462  slides rightward (moves in the horizontal direction), and thus the lens unit  407  also moves rightward, as shown in the left and right views of  FIG. 4B . Then, the lens unit  407  moves to a non-attachment position as a position (a position where no light beam is blocked) away from the path of the light beam from the optical engine  201 . 
     If the motor  408  is reversely rotated, the lens holder  462  slides leftward, and thus the lens unit  407  also moves leftward. Then, the lens unit  407  moves to a position (attachment position) on the path of the light beam from the optical engine  201 . With this moving mechanism  406 , the lens unit  407  can be automatically attached or released (detached). Note that the example of moving the lens holder  462  by the motor  408  has been explained. However, the lens holder  462  may be slid manually, instead of using the motor  408 . 
     According to this example embodiment, it is possible to automatically move the lens unit. Therefore, it is possible to attach/detach the lens unit easily, quickly, and reliably. 
     Fifth Example Embodiment 
     A three-dimensional shaping apparatus according to the fifth example embodiment of the present invention will be described with reference to  FIGS. 5A to 7 .  FIG. 5A  is a partially enlarged view showing an example of the attachment mechanism of the three-dimensional shaping apparatus according to this example embodiment.  FIG. 5B  is another partially enlarged view showing an example of the attachment mechanism of the three-dimensional shaping apparatus according to the fifth example embodiment of the present invention. The three-dimensional shaping apparatus according to this example embodiment is different from the above-described second to fourth example embodiments in that a controller is provided. The remaining components and operations are the same as those in the second to fourth example embodiments. Hence, the same reference numerals denote the same components and operations, and a detailed description thereof will be omitted. 
     A three-dimensional shaping apparatus  500  includes an optical engine  201 , a moving mechanism  406 , a lens unit  407 , a motor  408 , a linear actuator  509 , and a controller  510 . 
     The moving mechanism  406  moves the lens unit  407  between an attachment position and a non-attachment position. The motor  408  drives the moving mechanism  406  to move between the attachment position and the non-attachment position. This causes the lens unit  407  to move between the attachment position and the non-attachment position, thereby automatically attaching detaching the lens unit  407 . Note that the moving mechanism  406  for moving the lens unit  407  moves the lens unit  407  by a slide mechanism described with reference to  FIG. 4B . 
     The controller  510  controls movement (attachment/detachment) of the lens unit  407  and position adjustment of the optical engine  201  in synchronism with each other. That is, if, as shown in  FIG. 5A , no lens unit  407  is used (attached), the controller  510  controls movement of the lens unit  407  to the non-attachment position and position adjustment (downward movement) of the optical engine  201  to synchronize with each other. If, as shown in  FIG. 5B , the lens unit  407  is used (attached), the controller  510  controls movement of the lens unit  407  to the attachment position and position adjustment (upward movement) of the optical engine  201  to synchronize with each other. 
     Therefore, if, for example, the user of the three-dimensional shaping apparatus  500  selects use or nonuse of the lens unit  407 , the controller  510  automatically sets the position of the optical engine  201 . If, for example, the user of the three-dimensional shaping apparatus  500  selects the position of the optical engine  201 , the controller  510  automatically sets the attachment or non-attachment position of the lens unit  407 . 
       FIG. 6  is a table showing an example of a synchronization table provided in the three-dimensional shaping apparatus according to this example embodiment. A synchronization table  601  stores a lens holder position  612 , a lens type  613 , and an optical engine position  614  in association with lens unit presence/absence  611 . The lens unit presence/absence  611  indicates whether or not to use the lens unit  407 . The lens holder position  612  indicates the position of a lens holder  462 , that is determined in accordance with the presence/absence of use of the lens unit  407 . The lens type  613  indicates information about a lens included in the lens unit  407 , and information concerning the performance of the lens and the like. The optical engine position  614  indicates the position of the optical engine  201 , that is determined in accordance with the presence/absence of the lens unit  407  and the type of the lens used as the lens unit  407 . The synchronization table  601  is stored in, for example, the storage (not shown) of the three-dimensional shaping apparatus  500 . The controller  510  controls movement of the lens unit  407  and position adjustment of the optical engine  201  in synchronism with each other with reference to the synchronization table  601 . 
       FIG. 7  is a flowchart illustrating the operation procedure of the three-dimensional shaping apparatus according to this example embodiment. This flowchart is executed by a CPU (Central Processing Unit) of the controller  510 . In step S 701 , the three-dimensional shaping apparatus  500  determines whether to use the lens unit  407 . If it is determined to use the lens unit  407  (YES in step S 703 ), the three-dimensional shaping apparatus  500  advances to step S 703 . In step S 703 , the three-dimensional shaping apparatus  500  prepares for moving the lens unit  407  to the attachment position. If it is determined not to use the lens unit  407  (NO in step S 701 ), the three-dimensional shaping apparatus  500  advances to step S 705 . In step S 705 , the three-dimensional shaping apparatus  500  prepares for moving the lens unit  407  to the non-attachment position. 
     In step S 707 , the three-dimensional shaping apparatus  500  prepares for position adjustment of the optical engine  201  in accordance with the position of the lens unit  407 . That is, a specific position is determined as the position of the optical engine  201 . In step S 709 , the three-dimensional shaping apparatus  500  controls movement of the lens unit  407  and position adjustment of the optical engine  201  to synchronize with each other. That is, movement of the lens unit  407  and that of the optical engine  201  are controlled so as to synchronize with each other. 
     According to this example embodiment, since movement of the lens unit to the attachment positon and non-attachment position and position adjustment of the optical engine are controlled in synchronism with each other, it is possible to make setting of the apparatus easily, quickly, and correctly. In addition, it is possible to automatically set a focal length in accordance with the lens unit used. 
     Other Example Embodiments 
     While the invention has been particularly shown and described with reference to example embodiments thereof, the invention is not limited to these example embodiments. It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the claims. 
     The present invention is applicable to a system including a plurality of devices or a single apparatus. The present invention is also applicable even when an information processing program for implementing the functions of example embodiments is supplied to the system or apparatus directly or from a remote site. Hence, the present invention also incorporates the program installed in a computer to implement the functions of the present invention by the computer, a medium storing the program, and a WWW (World Wide Web) server that causes a user to download the program. Especially, the present invention incorporates at least a non-transitory computer readable medium storing a program that causes a computer to execute processing steps included in the above-described example embodiments.