Abstract:
An illumination apparatus including a light source that emits illumination light, an optical member that transmits the illumination light to externally project the illumination light, and a reflector that reflects illumination light from the light source towards the optical member, the device comprising: a drive device to drive the reflector and the light source to advance and retract in a substantially perpendicular direction relative to a light projection surface of the optical member; and a relative movement device to cause the light source to relatively move relative to the reflector in a process of driving to advance and retract by way of the drive device, wherein the relative movement device includes a straight guide member that causes the light source to move straight ahead in the substantially perpendicular direction relative to the reflector.

Description:
The present application claims priority under 35 U.S.C. §119 to Japanese Patent Application No. 2009-241961 filed on Oct. 21, 2009. The content of the application is incorporated herein by reference in its entirety. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an illumination apparatus. 
     2. Description of the Related art 
     Conventionally, an illumination apparatus exists that can automatically change its illumination angle to correspond to the focal length of the photographic lens. As a conventional example relating to this type of illumination apparatus, a flash device has been known that is made so that the light source is configured to freely swing on an optical axis direction with the axis of rotation as the pivot point, and the positional relationship between the light source and a reflector changes by way of this swinging (for example, Japanese Patent No. 3022295). 
     SUMMARY OF THE INVENTION 
     With the above-mentioned conventional example, since the light source swings on an arc about the center of rotational axis, when the amount of movement of the light source increases, the position of the light source deviates greatly from the optical axis. When the position of the light source deviates greatly from the optical axis in this way, the light distribution becomes vertically unsymmetrical, and the vertical luminance of the image becomes non-uniform. 
     The problem of the present invention is to provide an illumination apparatus that can make the light distribution vertically symmetrical, irrespective of the amount of movement of the light source. 
     The present invention solves the problem by the following solution. 
     Accordingly, an object of the present invention is to provide an illumination apparatus including a light source that emits illumination light, an optical member that transmits the illumination light to externally project the illumination light, and a reflector that reflects illumination light from the light source towards the optical member, the device comprising: a drive device to drive the reflector and the light source to advance and retract in a substantially perpendicular direction relative to a light projection surface of the optical member; and a relative movement device to cause the light source to relatively move relative to the reflector in a process of driving to advance and retract by way of the drive device, wherein the relative movement device includes a straight guide member that causes the light source to move straight ahead in the substantially perpendicular direction relative to the reflector. 
     The drive device may include a light source retaining member that retains the light source, and a reflector retaining member that retains the reflector, may be a device to support the light source retaining member to be movable in the substantially perpendicular direct, and to drive the reflector retaining member to advance or retract in the substantially perpendicular direction, and may further include a cam face that is provided along a path in which the reflector retaining member is driven to advance or retract and has a sloped surface at a portion thereof, wherein the relative movement device may include a depressing member having one end that abuts with the light source retaining member and another end that abuts with the cam face, and controls a position of the light source retaining member in the substantially perpendicular direction by way of the depressing member abutting the light source retaining member and the cam face, and wherein the relative movement device may cause the light source to relatively move relative to the reflector when the drive device performs driving to advance or retract, by way of the depressing device moving while abutting the sloped surface of the cam face. 
     The depressing member may be supported to be rotatable about a predetermined axis of rotation, and wherein the depressing member may be set so as enter different rotational states when moving while abutting with the sloped surface of the cam face and when moving while abutting a non-sloped face of the cam face, and may cause the light source to relatively move relative to the reflector by way of abutting with the sloped surface or the non-sloped surface of the cam face. 
     The depressing member may be supported to be reciprocally movable in an orthogonal direction to the substantially perpendicular direction, and wherein the depressing member may be set so as to move in the orthogonal direction by different amounts when moving while abutting with the sloped surface of the cam face and when moving while abutting a non-sloped surface of the cam face, and may cause the light source to relatively move relative to the reflector by way of abutting with the sloped surface or the non-sloped surface of the cam face. 
     The drive device may include a light source retaining member that retains the light source, and a reflector retaining member that retains the reflector, and may be a device that retains the light source retaining member to be moveable in the substantially perpendicular direction and drives the reflector retaining member to advance or retract in the substantially perpendicular direction by way of driving power emitted by a first drive source, and wherein the relative movement device may be drive the light source retaining member to advance or retract in the substantially perpendicular direction independently from the drive device, by way of driving power emitted by a second drive source that is different from the first drive source. 
     According to the present invention, it is possible to provide an illumination apparatus that can make the light distribution vertically symmetrical irrespective of the amount of the movement of the light source. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings attached, 
         FIG. 1A  is block diagram of an illumination apparatus according to a first embodiment; 
         FIG. 1B  is block diagram of an illumination apparatus according to a first embodiment; 
         FIG. 2A  is block diagram of an illumination according to a second embodiment; 
         FIG. 2B  is block diagram of an illumination apparatus according to a second embodiment; 
         FIG. 3A  is block diagram of an illumination apparatus according to a third embodiment and 
         FIG. 3B  is block diagram of an illumination apparatus according to a third embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Hereinafter, embodiments of an illumination apparatus according to the present invention will be explained while referring to the drawings. The illumination apparatus according to the present embodiments is mounted to a camera, which is not illustrated. The camera is provided with a camera body including an imaging unit that converts object light to electronic signals and outputs the electronic signals, and the like, and a photographic lens that captures the object light on a light receiving surface of the imaging unit. This photographic lens is a zoom lens having a focal length that is variable manually or electrically. The illumination apparatus according to the present embodiments is configured so as that the illumination angle automatically changes in accordance with the focal length of the photographic lens. 
     First Embodiment 
       FIGS. 1A and 1B  are block diagrams showing an illumination apparatus  1  according to a first embodiment.  FIG. 1A  shows a configuration when a zoom mechanism  20  is positioned to a telephoto side, and  FIG. 1B  shows a configuration when positioned to a wide-angle side. 
     The illumination apparatus  1  according to the present embodiment is configured with a light source unit  10  and a zoom mechanism  20 . The light source unit  10  includes a xenon tube  11 , a reflector  12 , and diffuser  13 . The xenon tube  11  is a light source that generates illumination light, and is a light emission tube that illuminates by way of electric power being supplied from a capacitor, which is not illustrated, to emit illumination light. It should be noted that the light source is not limited to a xenon tube, and may be a light emitting diode, for example. In addition, illustrations and explanations for a boosting circuit for causing the xenon tube  11  to illuminate and the like are omitted. Moreover, the reference numbers are partly omitted in  FIG. 1B . 
     The reflector  12  is a member that reflects illumination light from the xenon tube  11  towards the diffuser  13 . This reflector  12  is retained by a reflector retaining portion  31   a  of a reflector holder  31  described later. In the present embodiment, the luminescent center of the xenon tube  11  and the reflection center of the reflector  12  are positioned on the optical axis A of the light source unit  10 . This optical axis A is a line extending in a substantially perpendicular direction relative to a light projection surface of the diffuser  13  described later. 
     The diffuser  13  is an optical member that scatters illumination light from the xenon tube  11  and projects to outside. The diffuser  13  is disposed in an object direction (right-side direction in the figure) relative to the xenon tube  11 , which is the light source. It should be noted that the diffuser  13  is configured by a transparent or semi-transparent resin material, and has a Fresnel lens, which is not illustrated, provided on the projection surface. 
     The zoom mechanism  20  is configured by the light source retaining portion  30  and a light source drive unit  40 . The light source retaining portion  30  includes a reflector holder  31  and a xenon tube holder  32 . The reflector holder  31  is a member that is driven to advance or retract in the direction of the optical axis A of the light source unit  10  by way of the light source drive unit  40  described later. The reflector holder  31  includes a reflector retaining portion  31   a , a reflector holder engaging portion  31   b , a drive shaft engaging portion  31   c , and a straight guide member  31   d.    
     The reflector retaining portion  31   a  is a concave shape having a cross-section formed in a substantially trapezoidal shape. The aforementioned reflector  12  is retained to the reflector retaining portion  31   a . The reflector holder engaging portion  31   b  is a through-hole portion engaged by the reflector holder  31 . The reflector holder  31  is supported to be movable along the optical axis A in a state of being engaged with the reflector holder engaging portion  31   b.    
     The drive shaft engaging portion  31   c  is a threaded hole portion that engages with the drive shaft  41   a  of the light source drive unit  40 , and has female threads formed in the inner circumference. The drive shaft  41   a  of the light source drive unit  40  has male threads formed on the outer circumference. The male threads of the drive shaft  41   a  of the light source drive unit  40  and the female threads of the drive shaft engaging portion  31   c  are mutually engaged. Rotation of the reflector holder  31  relative to the drive shaft  41   a  restricted by a member, which is not illustrated. The reflector holder  31  is driven to advance or retract in the direction of the optical axis A depending on the rotational direction of the drive shaft  41   a . For example, it advances when the drive shaft  41   a  rotates in a clockwise direction, and retracts when rotating in the counterclockwise direction. The straight guide member  31   d  is a member that allows the xenon tube holder  32  retaining the xenon tube  11  to move straight ahead along the direction of the optical axis A relative to the reflector  12 . The straight guide member  31   d  engages with an engaging portion  32   b  of the xenon tube holder  32  described later. A spring  33  is attached to the straight guide member  31   d . The spring  33  is a member that biases the xenon tube holder  32  to the left side in the figure. 
     The xenon tube holder  32  is a member that causes the xenon tube  11  to be driven to advance or retract along the direction of the optical axis A. The xenon tube holder  32  includes a holder portion  32   a  that retains the xenon tube  11 , an engaging portion  32   b  that engages with the straight guide member  31   d  of the reflector holder  31 , and a depressed portion  32   c . The engaging portion  32   b  is a through-hole portion engaged by the straight guide member  31   d  of the aforementioned reflector holder  31 . The xenon tube holder  32  is locked to the left side in the figure by way of the biasing of the spring  33  when not being depressed by a drive lever  43  described later. At this time, the xenon tube  11  retained to the xenon tube holder  32  is at a position closest to the base portion of the reflector  12 . The depressed portion  32   c  is a part that is depressed by a depressing portion  43   b  of the drive lever  43  described later. 
     The light source drive unit  40  includes a motor  41 , a control circuit  42 , a drive lever  43 , and a cam face  44 . The motor  41  is a drive source that produces driving power for driving the reflector holder  31 . The motor  41  has the aforementioned drive shaft  41   a . The drive shaft  41   a  engages with the drive shaft engaging portion  31   c  of the reflector holder  31 . 
     The control circuit  42  is a circuit that controls rotation of the motor  41 , and is configured by a microprocessor such as a CPU. The control circuit  42  causes the reflector holder  31  engaging with the drive shaft  41   a  of the motor  41  to be driven to advance or retract in the direction of the optical axis A by way of controlling rotation of the motor  41  in accordance with the focal length of the aforementioned photographic lens. In other words, the control circuit  42  causes the reflector holder  31  to retract along the direction of the optical axis A (move to the left side in the figure) when the focal length of the photographic lens, which is not illustrated, moves from the wide-angle side to the telephoto side, and causes the reflector holder  31  to advances along the direction of the optical axis A (move to the right side in the figure) when the focal length of the photographic lens moves from the telephoto side to the wide-angle side. 
     The drive lever  43  is a member that depresses the xenon tube holder  32  and controls the position thereof in the direction of the optical axis A. The drive lever  43  is attached to a rotating shaft  47  provided to the reflector holder  31 . A spring, which is not illustrated and biases the drive lever  43  in the counterclockwise direction, is attached to the rotating shaft  47 . The drive lever  43  is biased in the counterclockwise direction about the rotating shaft  47  by the spring, and is supported to be rotatable also in the clockwise direction about the rotating shaft  47 . The drive lever  43  moves along the direction of the optical axis A along with the reflector holder  31 . 
     The cam face  44  is a member provided along the path in which the reflector holder  31  is driven to advance and retract. The cam face  44  is disposed to be fixed inside of the illumination apparatus. In addition, the cam face  44  has a flat surface  44   a , and a sloped surface  44   b  provided at one end thereof. 
     The drive lever  43  includes a sliding portion  43   a  on a lower end. The sliding portion  43   a  is a part that abuts with the cam face  44 . The drive lever  43  moves while abutting with the flat surface  44   a  or sloped surface  44   b  of the cam face  44  with movement of the reflector holder  31 . In addition, the drive lever  43  includes a depressing portion  43   b  at an upper end. 
     The drive lever  43  is biased in a counterclockwise direction about the rotating shaft  47  when the focal length of the photographic lens, which is not illustrated, moves from the wide-angle side to the telephoto side, due to the sliding portion  43   a  moving while abutting with the flat surface  44   a  of the cam face  44 . At this time, the depressing portion  43   b  does not abut the depressed portion  32   c  of the xenon tube holder  32 . As a result, the xenon tube holder  32  relatively moves to the left side in the figure relative to the reflector holder  31 , by way of the biasing force of the spring  33 . 
     In addition, the drive lever  43  rotates counterclockwise about the rotating shaft  47  when the focal length of the photographic lens, which is not illustrated, moves from the telephoto side to the wide-angle side, due to the sliding portion  43   a  moving while abutting with the sloped surface  44   b  of the cam face  44 . At this time, the depressing portion  43   b  depresses the depressed portion  32   c  of the xenon tube holder  32  in the right direction in the figure against the biasing force of the spring  33 . With this, the xenon tube holder  32  relatively moves to the right side in the figure relative to the reflector holder  31 . 
     Next, operations during zoom driving of the illumination apparatus  1  configured in the above-mentioned way will be explained. When the zoom mechanism  20  moves from the wide-angle side to the telephoto side, the reflector holder  31  engaging with the drive shaft  41   a  of the motor  41  retracts along the direction of the optical axis A (moves to the left side in the figure) by way of control of the control circuit  42 . At this time, the sliding portion  43   a  of the drive lever  43  moves while abutting with the flat surface  44   a  of the cam face  44 , as shown in  FIG. 1A . Herein, the sliding portion  43   a  of the drive lever  43  is biased in the counterclockwise direction by way of the spring, which is not illustrated, without torque being imparted from the cam face  44 . At this time, a state is entered in which depressing to the depressed portion  32   c  of the xenon tube holder  32  by the drive lever  43  has been released. 
     With this, the xenon tube holder  32  engaging with the straight guide member  31   d  of the reflector holder  31  moves straight ahead to a side opposite the diffuser  13  along the direction of the optical axis A by way of the biasing force of the spring  33 . As a result thereof, a space between the center of the xenon tube  11  and the base portion of the reflector  12  becomes h 1 . 
     On the other hand, when the zoom mechanism  20  moves from the telephoto side to the wide-angle side, the reflector holder  31  engaging with the drive shaft  41   a  of the motor  41  advances along the direction of the optical axis A (moves to the right side in the figure) by way of control of the control circuit  42 . At this time, the sliding portion  43   a  of the drive lever  43  moves while abutting with the sloped surface  44   b  of the cam face  44 , as shown in  FIG. 1B . Herein, torque in the clockwise direction about the rotating shaft  47  is imparted to the sliding portion  43   a  of the drive lever  43  by way of the sloped surface  44   b  of the cam face  44 . As a result, the drive lever  43  rotates clockwise against the biasing of the spring, which is not illustrated, and the depressing portion  43   b  of the drive lever  43  depresses the depressed portion  32   c  of the xenon tube holder  32  in the right direction in the figure against the biasing force of the spring  33 . 
     With this, the xenon tube holder  32  engaging with the straight guide member  31   d  of the reflector holder  31  moves straight ahead along the direction of the optical axis A to the side of the diffuser  13 . As a result thereof, the space between the center of the xenon tube  11  and the base portion of the reflector  12  becomes h 2  (&gt;h 1 ). 
     According to the illumination apparatus of the aforementioned first embodiment, in both cases of when the zoom mechanism  20  moves from the wide-angle side to the telephoto side, and when moving from the telephoto side to the wide-angle side, the xenon tube holder  32  moves straight ahead along the straight guide member  31   d  of the reflector holder  31 , when the xenon tube  11  relatively moves relative to the reflector  12 . As a result, the position of the xenon tube  11 , which is the light source, does not deviate from the optical axis A, irrespective of the amount of movement thereof. Therefore, the light distribution of the xenon tube  11  is vertically symmetrical both at the wide-angle side and the telephoto side, and the vertical luminance of the image is uniform. 
     In addition, according to the configuration of the present embodiment, the amount of relative movement of the xenon tube holder  32  relative to the reflector holder  31  can be controlled by appropriately selecting the length of the depressing portion  43   b  of the drive lever  43  in the direction of the optical axis A. 
     Second Embodiment 
       FIG. 2  is a block diagram of an illumination apparatus  1 A according to a second embodiment.  FIG. 2A  shows a configuration when a zoom mechanism  20 A is positioned to a telephoto side, and  FIG. 2  shows a configuration when positioned to a wide-angle side. Hereinafter, for equivalent parts to the first embodiment, the same reference symbols are assigned, and explanations are omitted. 
     The zoom mechanism  20 A of the present embodiment is configured by a light source retaining portion  30 A and a light source drive unit  40 A. The light source retaining portion  30 A includes a reflector holder  31 A and a xenon tube holder  32 A. The reflector holder  31 A includes a reflector retaining portion  31   a , reflector holder engaging portion  31   b , drive shaft engaging portion  31   c , straight guide member  31   d , and drive pin engaging portion  31   e . The drive pin engaging portion  31   e  is a through-hole portion through which a drive pin  45  described later is inserted. 
     The xenon tube holder  32 A includes a holder portion  32   a , engaging portion  32   b , and sloped portion  32   d . The sloped portion  32   d  is a sloped surface that is abutted by a depressing portion  45   b  of the drive pin  45  described later. When the depressing portion  45   b  of the drive pin  45  moves upwards in the figure against the biasing force of the spring  33  while abutting with the sloped portion  32   d , the xenon tube holder  32 A is depressed in the right direction in the figure, which is orthogonal to the movement direction of the drive pin  45 . In addition, when the depressing portion  45   b  of the drive pin  45  moves downwards in the figure while abutting with the sloped portion  32   d , the xenon tube holder  32 A is pressed back in the left direction in the figure, which is orthogonal to the movement direction of the drive pin  45 , by way of the biasing force of the spring  33 . 
     The light source drive unit  40  includes a motor  41 , control circuit  42 , cam face  44 , and drive pin  45 . The drive pin  45  is a member that depresses the xenon tube holder  32 A to control the position in the direction of the optical axis A. The drive pin  45  is inserted in the drive pin engaging portion  31   e  of the reflector holder  31 . In addition, a spring, which is not illustrated and biases the drive pin  45  downward in the figure, is provided to the drive pin  45 . The drive pin  45  is biased downward in the figure by the spring, and is supported to reciprocally move freely in a direction orthogonal to the direction of the optical axis A. 
     The drive pin  45  includes a sliding portion  45   a  on a lower end. The sliding portion  45   a  is a part that abuts with the cam face  44 . The drive pin  45  moves while abutting the flat surface  44   a  or sloped surface  44   b  of the cam face  44  with movement of the reflector holder  31 . In addition, the drive pin  45  includes a depressing portion  45   b  on an upper end. 
     When the focal length of the photographic lens, which is not illustrated, moves from the wide-angle side to the telephoto side, the drive pin  45  has movement in an upward direction orthogonal to the direction of the optical axis A restricted by way of the biasing force of a spring, which is not illustrated, since the sliding portion  45   a  moves while abutting with the flat surface  44   a  of the cam face  44 . As a result, the depressing portion  45   b  does not depress the sloped portion  32   d  of the xenon tube holder  32 A. Therefore, the xenon tube holder  32 A relatively moves to the left side in the figure relative to the reflector holder  31 A, by way of the biasing force of the spring  33 . 
     In addition, when the focal length of the photographic lens, which is not illustrated, moves from the telephoto side to the wide-angle side, the drive pin  45  moves only by a predetermined amount in the upward direction orthogonal to the direction of the optical axis A against the biasing force from the spring, which is not illustrated, since the sliding portion  45   a  moves while abutting with the sloped surface  44   b  of the cam face  44 . As a result, the depressing portion  45   b  depresses the sloped portion  32   d  of the xenon tube holder  32 A in the right direction in the figure against the biasing force of the spring  33 . With this, the xenon tube holder  32 A relatively moves to the right side in the figure relative to the reflector holder  31 A. 
     Next, operations during zoom driving of the illumination apparatus  1 A configured in the above-mentioned way will be explained. When the zoom mechanism  20 A moves from the wide-angle side to the telephoto side, the reflector holder  31 A engaging with the drive shaft  41   a  of the motor  41  retracts along the direction of the optical axis A (moves to the left side in the figure), by way of control of the control circuit  42 . At this time, the sliding portion  45   a  of the drive pin  45  moves while abutting with the flat surface  44   a  of the cam face  44 , as shown in  FIG. 2A . Herein, the sliding portion  45   a  of the drive pin  45  is biased downward by a spring, which is not illustrated, due to force in the upward direction not being imparted from the cam face  44 . At this time, a state is entered in which depressing to the sloped portion  32   d  of the xenon tube holder  32  by the drive pin  45  is released. 
     With this, the xenon tube holder  32 A engaging with the straight guide member  31   d  of the reflector holder  31 A moves straight ahead to a side opposite the diffuser  13  along the direction of the optical axis A. As a result thereof, the space between the center of the xenon tube  11  and the base portion of the reflector  12  becomes h 1 . 
     On the other hand, when the zoom mechanism  20 A moves from the telephoto side to the wide-angle side, the reflector holder  31 A engaging with the drive shaft  41   a  of the motor  41  advances along the direction of the optical axis A (moves to the right side in the figure) by way of control of the control circuit  42 . At this time, the sliding portion  45   a  of the drive pin  45  moves while abutting with sloped surface  44   b  of the cam face  44 , as shown in  FIG. 2B . Herein, a force in the upward direction is imparted to the sliding portion  45   a  of the drive pin  45  by way of the sloped surface  44   b  of the cam face  44 . As a result, the drive pin  45  moves in the upward direction against the biasing force of the spring, which is not illustrated, and the depressing portion  45   b  of the drive pin  45  depresses the sloped portion  32   d  of the xenon tube holder  32  in the right direction in the figure, against the biasing force of the spring  33 . 
     With this, the xenon tube holder  32 A engaging with the straight guide member  31   d  of the reflector holder  31 A moves straight ahead to the side of the diffuser  13  along the direction of the optical axis A. As a result thereof, the space between the center of the xenon tube  11  and the base portion of the reflector  12  becomes h 2  (&gt;h 1 ). 
     According to the illumination apparatus  1 A of the aforementioned second embodiment, in both cases of when the zoom mechanism  20 A moves from the wide-angle side to the telephoto side, and when moving from the telephoto side to the wide-angle side, the xenon tube holder  32 A moves straight ahead along the straight guide member  31   d  of the reflector holder  31 A, when the xenon tube  11  relatively moves relative to the reflector  12 . As a result, the position of the xenon tube  11 , which is the light source, does not deviate from the optical axis A, irrespective of the amount of movement thereof. Therefore, the light distribution of the xenon tube  11  is vertically symmetrical both at the wide-angle side and the telephoto side, and the vertical luminance of the image is uniform. 
     It should be noted that, according to the configuration of the present embodiment, the amount of relative movement of the xenon tube holder  32 A relative to the reflector holder  31 A can be controlled by appropriately selecting the length of the drive pin  45  and the slope of the sloped portion  32   d  of the xenon tube holder  32 A. 
     Third Embodiment 
       FIG. 3  is a block diagram of an illumination apparatus according to a third embodiment.  FIG. 3A  shows a configuration when a zoom mechanism  20 B is positioned to a telephoto side, and  FIG. 3B  shows a configuration when positioned to a wide-angle side. Hereinafter, for equivalent parts to the first embodiment, the same reference symbols are assigned, and explanations are omitted. 
     A zoom mechanism  20 B of the present embodiment is configured by a light source retaining portion  30 B and a light source drive unit  40 B. The light source retaining portion  30 B includes a reflector holder  31 B and a xenon tube holder  32 B. The reflector holder  31 B includes a reflector retaining portion  31   a , reflector holder engaging portion  31   b , drive shaft engaging portion  31   c , and second motor fixing portion  31   f . The second motor fixing portion  31   f  is a part that fixes a second motor  46  described later. 
     The xenon tube holder  32 B includes a holder portion  32   a  and a drive shaft engaging portion  32   e . The drive shaft engaging portion  32   e  is a threaded hole portion that engages with the drive shaft  46   a  of the second motor  46  described later, and has female threads formed in the inner circumference. 
     The light source drive unit  40 B includes a first motor  41 , control circuit  42 A, and second motor  46 . The first motor  41  is a first drive source that produces driving power for driving the reflector holder  31 B. It should be noted that, although described as a “first motor” in order to distinguish from the “second motor” in the present embodiment, the first motor  41  is the motor  41  of the first and second embodiments. The second motor  46  is a second drive source that produces driving power for driving the xenon tube holder  32 B. The second motor  46  includes the aforementioned drive shaft  46   a . The drive shaft  46   a  engages with the drive shaft engaging portion  32   e  of the xenon tube holder  32 B. In the present embodiment, the drive shaft  46   a  of the second motor  46  functions as a straight guide member that causes the xenon tube  11 , which is the light source, to move straight ahead in the direction of the optical axis A relative to the reflector  12 . 
     The control circuit  42 A is a circuit that controls rotation of the first motor  41  and the second motor  46 , and is configured by a microprocessor such as a CPU. The control circuit  42 A causes the reflector holder  31 B engaging with the drive shaft  41   a  of the first motor  41  to be driven to advance or retract in the direction of the optical axis A by way of controlling rotation of the first motor  41  in accordance with the focal length of the aforementioned photographic lens. In addition, the control circuit  42 A causes the xenon tube holder  32 B engaging with the drive shaft  46   a  of the second motor  46  to be driven to advance or retract in the direction of the optical axis A by way of controlling rotation of the second motor  46  in accordance with the focal length of the aforementioned photographic lens. 
     In other words, the control circuit  42 A causes the reflector holder  31 B to retract along the direction of the optical axis A (move to the left side in the figure) when the focal length of the photographic lens, which is not illustrated, moves from the wide-angle side to the telephoto side, by way of controlling rotation of the first motor  41 . In addition, the control circuit  42 A simultaneously causes the xenon tube holder  32 B to retract along the direction of the optical axis A (move to the left side in the figure) by way of controlling rotation of the second motor  46 . With this, the xenon tube holder  32 B relatively moves to the left side in the figure relative to the reflector holder  31 B. 
     In addition, the control circuit  42 A causes the reflector holder  31 B to advance along the direction of the optical axis A (move to the right side in the figure) when the focal length of the photographic lens, which is not illustrated, moves from the telephoto side to the wide-angle side, by way of controlling rotation of the first motor  41 . In addition, the control circuit  42 A simultaneously causes the xenon tube holder  32 B to advance along the direction of the optical axis A (move to the right side in the figure) by way of controlling rotation of the second motor  46 . With this, the xenon tube holder  32 B relatively moves to the right side in the figure relative to the reflector holder  31 B. 
     Next, operations during zoom driving of the illumination apparatus  1 B configured in the above-mentioned way will be explained. The reflector holder  31 B engaging with the drive shaft  41   a  of the first motor  41  retracts along the direction of the optical axis A (moves to the left side in the figure) when the zoom mechanism  20 B moves from the wide-angle side to the telephoto side, by way of control of the control circuit  42 A. At this time, the xenon tube holder  32 B engaging with the drive shaft  46   a  of the second motor  46  retracts along the direction of the optical axis A (moves to the left side in the figure) by way of control of the control circuit  42 A, as shown in  FIG. 3A . As a result thereof, the space between the center of the xenon tube  11  and the base portion of the reflector  12  becomes h 1 . 
     On the other hand, when the zoom mechanism  20 B moves from the telephoto side to the wide-angle side, the reflector holder  31 B engaging with the drive shaft  41   a  of the first motor  41  advances along the direction of the optical axis A (moves to the right side in the figure) by way of control of the control circuit  42 A. At this time, the xenon tube holder  32 B engaging with the drive shaft  46   a  of the second motor  46  moves straight ahead to the side of the diffuser  13  along the same direction of the optical axis A by way of control of the control circuit  42 A, as shown in  FIG. 3B . As a result thereof, the space between the center of the xenon tube  11  and the base portion of the reflector  12  becomes h 2  (&gt;h 1 ). 
     According to the illumination apparatus  1 B of the aforementioned third embodiment, in both cases of when the zoom mechanism  208  moves from the wide-angle side to the telephoto side, and when moving from the telephoto side to the wide-angle side, the xenon tube holder  32 B moves straight ahead along the drive shaft  46   a  of the second motor  46 , when the xenon tube  11  relatively moves relative to the reflector  12 . As a result, the position of the xenon tube  11 , which is the light source, does not deviate from the optical axis A, irrespective of the amount of movement thereof. Therefore, the light distribution of the xenon tube  11  is vertically symmetrical both at the wide-angle side and the telephoto side, and the vertical luminance of the image is uniform. 
     According to the present embodiment, the amount of relative movement of the xenon tube holder  32 B relative to the reflector holder  31 B can be controlled by appropriately setting the drive amount of the second motor  46  in the control circuit  42 A. 
     Modifications 
     Not being limited to the embodiments explained above, various modifications and alterations of the present invention are possible as shown below, and are also within the scope of the present invention. 
     (1) In each of the embodiments, it may be configured so that driving of the motor is performed by way of a control circuit of the camera to which the illumination apparatus is mounted. 
     (2) In the first (or second) embodiment, the amount of relative movement of the xenon tube holder  32  relative to the reflector holder  31  can change by way of appropriately selecting the sloped surface  44   b  of the cam face  44 . In other words, the slope of the sloped surface  44   b  may relax or be made steep, and different slopes may be combined, depending on the amount of movement of the xenon tube holder  32 . Furthermore, the sloped surface  44   b  may be made a curve (convex curve or concave curve). 
     (3) The drive lever  43  of the first embodiment or the drive pin  45  of the second embodiment may be configured so as to be driven using an actuator, which is not illustrated. 
     (4) In the third embodiment, rotation of the first motor  41  and second motor  46  is not limited to being controlled by one control circuit, and may be controlled by control circuits corresponding to the individual motors. 
     (5) The illumination apparatus according to the present invention is not only an external illumination apparatus mounted to a camera, and can also be applied to a built-in illumination apparatus of a camera. In addition, it is not only an illumination apparatus for a digital camera, and can also be applied as an illumination apparatus of a video camera. 
     Moreover, each of the above-mentioned embodiments and modifications can be used in combination as appropriate; however, detailed explanations thereof are omitted due to the configurations of each embodiment being clear from the drawings and explanations. Furthermore, the present invention is not to be limited by the embodiments explained above.