Patent Publication Number: US-2023152599-A1

Title: Framing system for shaping a light beam

Description:
FIELD OF THE DISCLOSURE 
     The present disclosure relates to a framing system arranged to shape a light beam by movement of a plurality of blades. 
     BACKGROUND 
     Framing systems for shaping a light beam typically comprise a number of shutter blades being moved in and out of the light beam in order to adjust the shape of the beam. 
     The light beam is typically shaped/delimited/framed by adjusting the position of each shutter blade relative to the light beam and thereby achieving the wanted framing of the light beam. The framing systems are typically used in light fixtures such as moving heads, follow spots and spotlights generating a light beam. Such light fixtures comprise a light source generating a light beam and a number of optical components generating different optical effects. 
     Prior art document WO 2007/134609 discloses a framing system comprising a number of shutter blades cooperating with a number of motors to move the shutter blades in and out of the light beam. The shutter blades form a merged pile, where the shutter blades in the merged pile are placed with the front area placed over the front area of a first neighbouring shutter blade and the front area placed below the front area of the second neighbouring shutter blade. Forming the shutter blades in a merged pile leads to a thin assembly, where the operating edges of the shutters are operating substantially in the same plane. The shutter blades are movable mounted and co-operates with motors to move the shutter means in and out of the light beam. The shutter blades comprise a front end to delimit the beam of light and the two toothed sides and interacting with pinions on the motors. One motor is placed in a fixed position, and second motor is movable in a sideward direction. The two motors allow movement and adjustment of the individual shutter blades in order to delimit the light beam. 
     The framing system disclosed in WO 2007/134609 is however not very useful as it is very hard to manufacture. The toothed sides of the framing blades tend to break during use, especially during long-term use. The shutter blades must further be moved in a very controlled manner, as the shutter blades can be move in and out of the merged pile causing crucial failure of the framing system. This can for instance occur if the corners of two adjacent shutter blades are moved too far away from each other, which results is in the shutter blades getting mixed up so that they will not work properly. 
     SUMMARY 
     It is an object of embodiments of the disclosure to provide an improved framing system for shaping a light beam. 
     According to an aspect, the disclosure provides a framing system for shaping a light beam, the framing system comprising:
         a first shutter system comprising a first blade and a second blade,   a second shutter system comprising a third blade and a fourth blade,   a blade divider forming an aperture, the first shutter system and the second shutter system being arranged on opposite sides of the blade divider,       wherein each blade constitutes an intermediate bar in a five-bar linkage between two sets of outer bars, each set comprising a motorized bar and a passive bar, and   wherein at least one of the motorized bars has a length being larger than a diameter of the aperture.   

     The framing system comprises a first shutter system and a second shutter system, where the first shutter system comprises a first blade and a second blade and the second shutter system comprises a third blade and a fourth blade. The first and second blades are arranged substantially in the same plane, in a first plane. Likewise, are the third and fourth blades arranged substantially in the same plane, in a second plane, where the first and second planes are substantially parallel. 
     By movement of the first, second, third, and fourth blades in and out of a light beam, the shape of the light beam may be changed. It may be possible to move each of the first, second, third, and fourth blades individually. It should be understood, that the framing system may be built into a light fixture which may comprise additional filters, apertures, and other optical devices which may enable additional shaping of the light beam. 
     The first shutter system and the second shutter system are arranged on opposite sides of a blade divider, which blade divider forms an aperture. The aperture may define the largest dimension of the size of the light beam within the framing system in a direction transverse to the light beam, as the blade divider forming the aperture may be arranged transverse to the light source. The largest dimension of the light beam in a direction transverse to the light beam may occur when each of the blades are moved away from the aperture, so that no part of the aperture is shaded by a blade. 
     In one embodiment, the aperture may have a circular form. It should however be understood that the aperture may alternatively be elliptical, oval, or any other shape. In an embodiment, in which the aperture is circular, the size of the aperture may be defied by the diameter of the aperture. In alternative embodiments, in which the aperture is non-circular, the term “diameter” may be used to define the largest crosswise size; i.e. the largest size of the aperture in a direction transverse to the aperture. Thus, the use of the term “diameter” does not limit the disclosure to apertures having a circular shape. 
     By arranging the first and second shutter system on opposite sides of the blade divider forming the aperture, the first, second, third, and fourth blades may be arranged close to each other while still being arranged so that the first and second blades are on one side and the third and fourth blades are on the opposite side of the blade divider. When lowering the distance between the blades and the aperture, it may be possible to shape the light beam more precisely as light escaping between the blades and the blades diving may be omitted or at least considerably reduced. Furthermore, when arranging the first and second blades in a first plane, and the third and fourth blades in a second plane, where the first and second planes are substantially parallel and arranged on opposite sides of the blade divider, the number of layers may be reduced whereby the risk of overheating the framing system may be reduced. 
     Each of the first, second, third, and fourth blades constitutes an intermediate bar in a five-bar linkage between two sets of outer bars, each set comprising a motorized bar and a passive bar. Thus, each blade is arranged as the middle bar in a five-bar linkage between two sets of outer bars. Each of the sets of outer bars comprises a passive bar and a motorized bar. Preferably, the outermost bar in each of the sets of outer bars may be the motorized bar. 
     The outermost bar of each of the sets of outer bars may be pivotally arranged around an outer pivot, where the outer pivot may be arranged substantially at one end of the outermost bar. At the other end, the outermost bar may be attached to the second bar of the set of outer bars. The two bars may be attached to each other at a floating pivot to allow movement of the bars. 
     At least one of the motorized bars has a length being larger than a diameter of the aperture. By providing, at least one of the blades with a motorized bar with a length being larger than the diameter of the aperture, a single blade may be moved to fully cover the aperture at a wide range of angles of the blade, such as a range of at least +/−30 degrees. 
     Preferably, each of the motorized bars may have a length being larger than the diameter of the aperture to allow each blade to be moved to fully cover the aperture at a wide range of angles of the blade. 
     The length of the bars may be defined as the distance between two pivot points. Thus, the length of each of the motorized bars may be the distance between the outer fixed pivot point and the floating pivot point. The length of each of the passive bars may be distance between the floating pivot point and the attachment point at the respective blade (the intermediate bar), where the attachment point may preferably be a second floating pivot point. 
     Each blade may have a width being defined as the dimension of the blade in a direction parallel to a line extending between the two attachment points for the passive bars of the two sets of outer bars forming part of the five-bar linkage in which the blade forms the intermediate bar. In one embodiment, the width of the blade may increase in a direction perpendicular to the line between the two attachments points to form a blade substantially in the form of a trapezoid. 
     Each blade may have a height being defined as the dimension of the blade in a direction perpendicular to the width of the blade. In one embodiment, both the height and the width may be larger than the diameter of the aperture to thereby provide the ability of fully shading the aperture with a single blade. 
     It should be understood that each of the blades may have a width and a height being at least of the same size than the diameter of the aperture. 
     The framing system may further comprise a first blade guide and a second blade guide, where the first shutter system may be arranged between the blade divider and the first blade guide, and where the second shutter system may be arranged between the blade divider and the second blade guide. The first and second blade guides may each comprises a spring structure arranged to exert a pressure towards the first and second shutter system, respectively. By exerting a pressure towards the first and second shutter system, respectively, the movement of the blades may substantially be in only one plane; i.e. substantially parallel to the blade divider. Furthermore, the risk of bending of the blades due to high temperatures may be limited. In one embodiment, the spring structure may comprise a leaf spring. 
     The surfaces of the blades may be formed by a low frictional material to facilitate movement of the blades along the blade divider between the blade divider and the first and second blade guide, respectively. 
     A pin may extend from each of the blades, where each pin may extend through a corresponding slot in one of the first and second blade guides to constrain movement of each of the blades. The pin may extend from the outer surface of the blade in a direction away from the blade divider. A pin extending from the first blade may extend through a corresponding slot in the first blade guide. Likewise, may a pin extending from the second blade extend through a slot in the first blade guide. Oppositely, may a pin extending from the third blade and a pin extending from the fourth blade extend through corresponding slots in the second blade guide. 
     The respective pins may be movable arranged in the respective slots to constrain movement of the blades to a linear movement while at the same time allowing pivotal movement of the blades to thereby allow tilting of the blade during the linear movement and allow change of the tilt angle during the linear movement. 
     Each blade may be movable within a range of at least +/−30 degrees for any position of the pin in the corresponding slot, such as within a range of +/−40 degrees, +/−50 degrees, +/−60 degrees, or even higher. 
     As specified above, each of the motorized bars may extend between a fixed pivot point and a floating pivot point. Each of the motorized bars may be rotatable around the fixed pivot point between an upper limit position and a lower limit position. A blade may be rotated at least 30 degrees, such as at least 35 degrees, such as at least 40 degrees, such as at least 45 degrees, such as at least 50 degrees, or even more, when one of the associated motorized bars is in the upper limit position and the other one of the associated motorized bars is in the lower limit position. 
     To allow a light beam to pass through the framing system having a first blade guide and a second blade guide arranged on opposite sides of the first shutter system and second shutter system, respectively, the first blade guide may form a first aperture, and the second blade guide may form a second aperture, whereby a light beam may pass the first blade guide, then the blade divider, and finally the second blade guide. It should be understood that a light beam may likewise pass in the other direction; i.e. first through the second blade guide, then through the blade divider and finally through the first blade guide, as the numbering of first and second does not provide a limitation to the disclosure. 
     In one embodiment, the aperture, and the first and second apertures may be co-axially arranged. 
     A first slot and a second slot may be arranged in the first blade guide, whereas a third slot and a fourth slot may be arranged in the second blade guide. The first and second slots may be arranged to cooperate with a pin extending from the first and second blade, respectively, whereas the third and fourth slots may be arranged to cooperate with a pin extending from the third and fourth blade, respectively. 
     The first and second blade guide may each be formed as a substantially flat element, e.g. formed by a sheet material, such as a sheet of metal. The first aperture and the first and second slots may be formed as through holes in the substantially flat element forming the first blades guide, whereas the second aperture and the third and fourth slots may be formed as through holes in the substantially flat element forming the second blades guide. The first and second slots may extend on opposite sides of the first aperture, whereas the third and the fourth slots may extend on opposite sides of the second aperture. The first, second, third, and forth slots may be elongated openings having a width being considerable smaller than the length hereof. As an example, the width of a slot may be less than 20% of the length of a slot, such as less than 15%, such as less than 10%. The length of a slot may be larger than the diameter of the first and second aperture, such as 10% larger, such as 15% larger, such as 20% larger. 
     The framing system may further comprise a rotatable frame portion, where the first shutter system, the second shutter system, and the blade divider may be attached to the frame portion for rotation of the first and second shutter systems and the blade divider with the frame portion. The rotatable frame portion may as an example be arranged for rotation in a light fixture. The rotatable frame portion may be rotatably attached to a static frame portion which may be fixedly attached to a light fixture, such as inside a moving head. 
     The blade divider may be formed as a substantially flat element, e.g. formed by a sheet material, such as a sheet of metal. In one embodiment, the blade divider may be fixedly attached to the rotatable frame portion at a single point. Additionally, the blade divider may be movably attached to the rotatable frame portion by at least one spring structure, such as by two spring structures, such as by three spring structures, or by more spring structures. Thus, the blade divider may be stretched between the single attachment point to which it is attached and the additional attachment point(s) at which the spring structure(s) may be attached to thereby from a drum-skin-like structure. This may counteract the thermal expansion of the blade divider when heated by the light beam. 
     The first and second shutter systems may be attached to the rotatable frame portion by via the motorized bars which may each be attached to the rotatable frame portion at the fixed pivot point. 
     The first and second blade guides may likewise be attached to the rotatable frame portion. In one embodiment, the first and second blade guides may be at least partly attached via the spring structure arranged to allow the first and second blade guides to exert a pressure towards the first and second shutter system, respectively. 
     The framing system may further comprise an anti-collision system configured to control movement of the blades to avoid collision between the first blade and second blade and between the third blade and fourth blade, respectively. The anti-collision system may in one embodiment form part of a control system configured to also control rotation of a rotatable frame portion and/control of a light fixture in which the framing system may be integrated. It should, however, be understood, that the anti-collision system may be a separate system which may be in communication with a control system configured to also control rotation of a rotatable frame portion and/control of a light fixture. 
     In one embodiment, the anti-collision system may comprise a memory arranged to read an angular position of each of the motorized bars. The anti-collision system may further comprise a kinematic model configured to transform the angular position of the motorized bars to define an orientation and a position of the blades to control that the first and second blades and the third and fourth blades, respectively, do not overlap to thereby avoid collision between the first blade and second blade and between the third blade and fourth blade, respectively. 
     The framing system may comprise a plurality of actuators, where an actuator may be operatively attached each of the motorized bars. The actuators may be arranged for movement of the blades. In one embodiment, at least one of the actuators may comprise a step motor. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the disclosure will now be further described with reference to the drawings, in which: 
         FIG.  1    illustrates an exploded view of an embodiment of a framing system; 
         FIG.  2    illustrates an assembled view of an embodiment of a framing system; 
         FIG.  3    illustrates an embodiment of a blade divider; 
         FIG.  4    illustrates an embodiment of a first blade guide; 
         FIG.  5    illustrates an embodiment of a second blade guide; 
         FIG.  6    illustrates an embodiment of a second shutter system; 
         FIG.  7    illustrates an embodiment of a first shutter system; 
         FIGS.  8 A- 8 D  illustrates different steps in of a +30 degrees full curtain framing; 
         FIGS.  9 A- 9 C  illustrates different steps in of a 0 degrees full curtain framing; 
         FIG.  10    illustrates a first and a second blade doing 30 degrees framing; 
         FIG.  11    illustrates a first, a second, a third, and a fourth blade arranged to form a parallelogram; and 
         FIG.  12    schematically illustrates a section through an embodiment of a framing system integrated in a moving head light system. 
     
    
    
     DETAILED DESCRIPTION 
     It should be understood that the detailed description and specific examples, while indicating embodiments of the disclosure, are given by way of illustration only, since various changes and modifications within the spirit and scope of the disclosure will become apparent to those skilled in the art from this detailed description. 
       FIG.  1    illustrates an exploded view of an embodiment of a framing system  10  for shaping a light beam (not shown). The framing system  10  comprises a first shutter system  12  and a second shutter system  14 , where the first shutter system  12  comprises a first blade  16  and a second blade  18 , and where the second shutter system  14  comprises a third blade  20  and a fourth blade  22 . 
     The framing system  10  further comprises a blade divider  24  forming an aperture  26 . The first shutter system  12  and the second shutter system  14  are arranged on opposite sides of the blade divider  24 . 
     A light source  210  (see also  FIG.  12   ) is arranged to generate a light beam which passes through the aperture  26  of the blade divider  24 . By movement of the first blade  16 , the second blade  18 , the third blade  20 , and the fourth blade  22  in and out of a light beam, the shape of the light beam can be changed. It may be possible to move each of the first, second, third, and fourth blades  16 ,  18 ,  20 ,  22  individually. 
     Each blade  16 ,  18 ,  20 ,  22  constitutes an intermediate bar  16 ,  18 ,  20 ,  22  in a five-bar linkage between two sets of outer bars  30 ,  32 , each set comprising a motorized bar  30  and a passive bar  32 . Each of the motorized bars  30  has a length being larger than the diameter of the aperture  26 . 
     The framing system  10  further comprises a first blade guide  34  and a second blade guide  36 . The first shutter system  12  is arranged between the blade divider  24  and the first blade guide  34 , whereas the second shutter system  14  is arranged between the blade divider  24  and the second blade guide  36 . 
     Each of the motorized bars  30  extends between a fixed pivot point  38  and a floating pivot point  40 . Each of the passive bars  32  extends between the floating pivot point  38  and the attachment point  42  at the respective blade  16 ,  18 ,  20 ,  22  (the intermediate bar). Each of the attachment points  42  are a second floating pivot point. 
     As specified above, each of the motorized bars  30  has a length being larger than the diameter of the aperture  26 , where the length of the motorized bar  30  is defined as the distance between the fixed pivot point  38  and the floating pivot point  40 . 
     The framing system  10  comprises a plurality of actuators  44  (see e.g.  FIGS.  6  and  7   ), where an actuator  44  is operatively attached each of the motorized bars  30 , and thereby is arranged for movement of the blades  16 ,  18 ,  20 ,  22 . 
     A pin  50  (see also  FIG.  7   ) extends from each of the blades  16 ,  18 ,  20 ,  22  through a corresponding slot  52  (see also  FIGS.  4 ,  5 , and  7   ) in one of the first and second blade guides  34 ,  36  to constrain movement of the blades  16 ,  18 ,  20 ,  22 . 
     The pin  50  extend from the outer surface of the blade  16 ,  18 ,  20 ,  22  in a direction away from the blade divider  24 . The pins  50  extending from the first blade  16  and the second blade  18  extend through corresponding slots  52  in the first blade guide  34 , whereas pins  50  extending from the third blade  20  and the fourth blade  22  extend through corresponding slots  52  in the second blade guide  36 . 
     To allow a light beam to pass through the framing system  10 , the first blade guide  34  forms a first aperture  54 , and the second blade guide  36  forms a second aperture  56 . In the illustrated embodiment, the aperture  26 , and the first and second apertures  54 ,  56  are co-axially arranged. 
     The framing system  10  further comprises a rotatable frame portion  60 . The rotatable frame portion  60  may be arranged for rotation in a light fixture  200  (see  FIG.  12   ). To allow rotation of the rotatable frame portion  60 , it may be rotatably attached to a static frame portion  80  (see e.g.  FIG.  8 A ) being fixedly attached to the light fixture. 
       FIG.  2    illustrates an assembled view of an embodiment of a framing system  10 . The framing system  10  further comprises a rotatable frame portion  60 . The first shutter system  12 , the second shutter system  14 , the blade divider  24 , and the first and second blades guides  34 ,  36  are attached to the frame portion  60  for rotation of the first and second shutter systems  12 ,  14 , the first and second blade guides  34 ,  36 , and the blade divider  24  with the rotatable frame portion  60 . The rotatable frame portion  60  may as an example be arranged for rotation in a light fixture  200  (see  FIG.  12   ). 
       FIGS.  3 - 7    illustrate embodiments of a blade divider  24 , a first blade guide  34 , a second blade guide  36 , a second shutter system  14 , and a first shutter system  12 , respectively. Each of these elements are individually disclosed while attached to a rotatable frame portion  60  to illustrate the elements in more detail and to illustrate their individual attachment structures to enable attachment hereof to the rotatable frame portion  60 . 
       FIG.  3    illustrates an embodiment of a blade divider  24 . The blade divider  24  is formed as a substantially flat element. The blade divider  24  is fixedly attached to the rotatable frame portion  60  at a single point  62 . Additionally, the blade divider  24  is movably attached to the rotatable frame portion  60  by a plurality of spring structures  64  in the form of leaf springs. Thus, the blade divider  24  is stretched between the single attachment point  62  to which it is fixedly attached and the additional attachment points at which the spring structures  64  are attached to thereby form a drum-skin-like structure. 
       FIGS.  4  and  5    illustrate an embodiment of a first blade guide  34  ( FIG.  4   ) and an embodiment of a second blade guide  36  ( FIG.  5   ). 
     The first and second blade guides  34 ,  36  are likewise attached to the rotatable frame portion  60 . The first and second blade guides  34 ,  36  are at least partly attached via a spring structure  66  arranged to ensure that the first and second blade guides  34 ,  36  exert a pressure towards the first and second shutter system, respectively. By exerting a pressure towards the first and second shutter systems  12 ,  14 , respectively, the movement of the blades  16 ,  18 ,  20 ,  22  may substantially be in only one plane; i.e. substantially parallel to the blade divider  24 . Furthermore, the risk of bending of the blades  16 ,  18 ,  20 ,  22  due to high temperature can be limited. 
     Each of the first and second blade guides  34 ,  36  are as the blade divider  24  attached to form drum-skin-like structures. 
       FIGS.  6  and  7    illustrates an embodiment of a first shutter system  12  ( FIG.  7   ) and an embodiment of a second shutter system  14  ( FIG.  6   ). 
     The first and second shutter systems  12 ,  14  are attached to the rotatable frame portion  60  via the motorized bars  30  at the fixed pivot points  38 . 
       FIGS.  8 A- 8 D  illustrates different steps in of a +30 degrees full curtain framing, where  FIG.  8 A  illustrates the first step and  FIG.  8 D  illustrates the last step. The framing system  10  comprises a rotatable frame portion  60  being rotatably attached to a static frame portion  80  which can be fixedly attached to a light fixture, such as inside a moving head. 
     In the first step, the first blade  16  and the second blade  18  are arranged with their outer portion facing each other in parallel. The pin  50  of each of the first and second blades  16 ,  18  are in the outermost position in the corresponding slots  52 ; i.e. at the position away from the aperture  26  in the blade divider  24 . 
     In the second step ( FIG.  8 B ) and the third step ( FIG.  8 C ), the second blade  18  remains at this position, while the first blade  16  in the second step is tilted to an angle of 30 degrees by use of the motorized bars  30  attached to the first blade. In the third step, the first blade  16  is moved towards the aperture  26  to partly shade the aperture, while maintain at an angle of 30 degrees relative to the starting position. The first blade  16  is moved by used of the motorized bars  30 . 
     In the fourth step ( FIG.  8 D ), the first blade  16  fully shades the aperture  26  at an angle of 30 degrees relative to its starting position. The pin  50  of the first blade  16  is moved to the other end of the corresponding slot  52 . To avoid collision with the second blade  18 , the second blade  18  is tilted 30 degrees relative to its starting position by use of the motorized bars  30  attached to the second blade  18 . The pin  50  of the second blade  18  is still in the outermost position in the corresponding slot  52 ; i.e. at the position away from the aperture  26  in the blade divider  24 . 
       FIGS.  9 A- 9 C  illustrates different steps in of a 0 degrees full curtain framing, where  FIG.  9 A  illustrates the first step, and  FIG.  9 C  illustrates the third step. 
     In the first step, the first blade  16  and the second blade  18  are arranged with their outer portion facing each other in parallel. The pin  50  of each of the first and second blades  16 ,  18  are in the outermost position in the corresponding slots  52 ; i.e. at the position away from the aperture  26  in the blade divider  24 . 
     In the second step ( FIG.  9 B ) and the third step ( FIG.  9 C ), the second blade  18  remains at this position, while the first blade  16  in the second step is moved towards the aperture  26  to partly shade the aperture without tilting the first blade  16 . The first blade  16  is moved by used of the motorized bars  30  attached hereto. 
     In the third step ( FIG.  9 C ), the first blade  16  fully shades the aperture  26 . The pin  50  of the first blade  16  is moved to the other end of the corresponding slot  52 . 
       FIG.  10    illustrates a first and a second blade  16 ,  18  doing 30 degrees framing. The first blade  16  and the second blade  18  have both been tilted to form a common angle of 30 degrees by use of the respective motorized bars  30  attached to each of the first blade and the second blade  16 ,  18 . Additionally, the position of the first and the second blades  16 ,  18  have been changed, whereby the pins  50  of each of the first and second blade  16 ,  18  has been moved towards the aperture  54  of the first blade guide  34 . 
       FIG.  11    illustrates a first, a second, a third, and a fourth blade  16 ,  18 ,  20 ,  22  arranged to form a parallelogram. The position of the first and the second blades  16 ,  18  have been changed by moving them towards the aperture  26  to partly shade the aperture without tilting the first and second blades  16 ,  18 . The pins  50  of each of the first and second blade  16 ,  18  has been moved towards the aperture  54  of the first blade guide  34 . The third blade  20  and the fourth blade  22  have both been tilted while their outer portions facing each other are still parallel use of the respective motorized bars  30  attached to each of the third blade and the fourth blade  20 ,  22 . The position of the third and the fourth blades  20 ,  22  have additionally been changed by moving them towards the aperture  26  to partly shade the aperture. 
       FIG.  12    schematically illustrates a section through an embodiment of a framing system  10  integrated in a moving head light system  200  comprising a light source  210 . The moving head light system  200  comprise a base  202 , a yoke  204 , and a head  206 , where the light source and the framing system  10  are arranged in the head  206 . Two motors  208 A,  208 B are arranged for movement of the head  206 , where the motor  208 A is for rotation of the head  206 , whereas the motor  208 B is for tilting of the head  206 . 
     To enable additional shaping of the light beam, a zoom device  212  and a focus device  214  are arranged in the head  206 . It should be understood that the moving head light system  200  may further comprise other optical devices. 
     An external computer  300  is in communication with a controller  220  integrated in the base  202 . The controller  220  is arranged to control rotation of the rotatable frame portion  60 , to control the light source  201 , to control movement the head, etc. Additionally, an anti-collision system configured to control movement of the blades  16 ,  16 ,  20 ,  22  to avoid collision between the first blade  16  and second blade  18  and to avoid collision between the third blade  20  and fourth blade  22 , respectively, forms part of the controller  220 . Additionally, a driver board  222  is arranged in the head  206  for control of the head  206  and the light source  210 . The driver board  222  is in communication with the controller  220 . 
     In the illustrated embodiment, the base  202  further comprises a user input element  224 . The user input element  224  may as an example comprise bottoms, touch pad(s), a keyboard, etc. Additionally, the base  202  comprises a display  226  enabling a user to interact with the user input element  224 .