JP5009250B2 - Imaging unit and imaging apparatus - Google Patents

Description

  The present invention relates to an imaging unit and an imaging apparatus including an imaging element that can be displaced in a two-dimensional direction orthogonal to the optical axis of a photographing lens.

  An electronic camera including an image sensor such as a CCD receives a transmitted light beam of a photographing lens by an image sensor and obtains image data based on the photoelectric conversion output. Here, since the image pickup device itself generates heat, a dark current is generated by the heat, and noise is caused to deteriorate the image quality. Therefore, various heat dissipation measures have been taken conventionally.

  On the other hand, recent electronic cameras include an image blur correction drive mechanism that moves the image sensor in a two-dimensional direction orthogonal to the optical axis, and for image blur correction so as to correct image blur when image blur is detected. Some have a camera shake correction function in which the image pickup device is displaced by a drive mechanism. In this case, the heat radiating member for radiating heat of the image pickup device cannot be directly attached to the movable part, and some device is required for heat radiation countermeasures.

  Therefore, for example, in Patent Document 1, heat is transferred from the movable heat radiating member to the fixed heat radiating member by placing the surfaces of the movable heat radiating member and the fixed heat radiating member as close as possible to face each other. Moreover, in patent document 2, heat is transferred from the movable side to the fixed side by interposing a magnetic fluid between the heat radiation plates facing the movable side and the fixed side.

JP 2006-174226 A JP 2006-31027 A

  However, the method according to Patent Document 1 dissipates heat generated on the movable member side into the air inside the camera casing by convection, transfers the heat to components inside the casing, and dissipates the heat outside the camera casing. Since an air layer having a large thermal resistance is interposed in the heat transfer path between the portion to be cooled and the heat radiating member, the heat transfer efficiency is poor and the heat dissipation efficiency is not good.

  Further, the method according to Patent Document 2 requires prevention of flow out of a magnetic fluid that functions as a heat transfer member, and the structure becomes complicated.

  The present invention has been made in view of the above, and can efficiently dissipate heat on the imaging element side that can be displaced in a two-dimensional direction orthogonal to the optical axis of the photographing lens without complicating the structure. An object is to provide an imaging unit and an imaging apparatus.

  In order to solve the above-described problems and achieve the object, the imaging unit according to the present invention is disposed on the optical axis of the photographing lens so as to be orthogonal to the optical axis, and an object image is formed by the photographing lens. An image pickup device, a heat-radiating support plate on which the image pickup device is mounted, a heat-dissipating fixing member fixedly disposed at a position facing the back surface of the support plate, and the image pickup device. In addition, a drive mechanism that moves the support plate in a two-dimensional direction perpendicular to the optical axis with respect to the fixed member, a temperature sensor that detects the temperature in the vicinity of the imaging element, and heat conduction that contacts and separates from the support plate A movable heat radiating plate that is movably disposed on the side of the fixed plate facing the support plate, and has a heat dissipation property and is thermally coupled to the fixed member and the movable heat radiating plate. Movement of the movable heat sink with respect to A guide member that is idled, and the fixing member so that the heat conducting portion comes into contact with the support plate when energized when a temperature in the vicinity of the imaging element detected by the temperature sensor is equal to or higher than a predetermined temperature. An energization drive mechanism that generates a driving force for moving the movable heat sink, and the movable heat sink is returned to the fixed member so that the heat conducting portion is separated from the support plate when the energization drive mechanism is not energized. And an elastic member to be moved.

  In the imaging unit according to the present invention as set forth in the invention described above, the energization drive mechanism is an electromagnetic drive mechanism that generates an electromagnetic drive force when the coil is energized.

  The imaging unit according to the present invention is characterized in that, in the above invention, the electromagnetic drive mechanism is a combination of a magnetic core around which an excitation coil or a drive coil is wound and a permanent magnet.

  Further, in the imaging unit according to the present invention, in the above invention, the magnetic core is disposed on the movable heat radiating plate with an axis centered along the optical axis, and also serves as the heat conducting unit. The magnet is made of a rubber magnet or a rare earth magnet, and is disposed on the support plate so as to face the magnetic core. When the excitation coil is energized, an electromagnetic attractive force is generated between the magnetic core and the permanent magnet. It is generated.

  Further, in the imaging unit according to the present invention, in the above invention, the magnetic core is disposed on the fixed member with an axis centered along the optical axis, the permanent magnet is a neodymium magnet, and the magnetic flux direction is changed. An electromagnetic driving force that is arranged on the movable heat sink so as to be orthogonal to the optical axis and close to the magnetic core, and to move the magnetic core and the permanent magnet relatively by energizing the drive coil. Is generated.

  In the imaging unit according to the present invention as set forth in the invention described above, the energization drive mechanism is a shape memory alloy spring that generates a spring force as a drive force when energized.

  In the imaging unit according to the present invention, in the above invention, the shape memory alloy spring is disposed between the movable heat sink and the fixed member, and is disposed between the movable heat sink and the fixed member. And a heat conductive sheet.

  In the imaging unit according to the present invention as set forth in the invention described above, the heat conducting portion is connected to a shield plate of a display device thermally coupled to the fixing member by a wire member that conducts heat.

  Further, an imaging apparatus according to the present invention is detected by the imaging unit according to the invention described above, a camera body in which the imaging lens is mounted and the fixing member is fixedly arranged and the imaging unit is built in, and the temperature sensor. Control means for controlling energization of the energization drive mechanism based on temperature.

  According to the imaging unit and the imaging apparatus according to the present invention, when the temperature near the imaging element rises to a predetermined temperature or more, the energization driving mechanism is energized to generate a driving force, and the movable heat sink is attached to the fixed member. By moving the heat conducting part of the movable heat radiating plate in contact with the heat radiating support plate for the image sensor, heat transfer from the support plate side to the fixing member side having the heat radiating property is performed by the heat conducting part and the movable heat radiating plate. For this reason, the contact of the heat conducting part with the support plate can be realized without hindering the displacement movement on the support plate side and without complicating the structure. There is an effect.

  The best mode for carrying out an imaging unit and an imaging apparatus according to the present invention will be described below with reference to the drawings. An image pickup apparatus including the image pickup unit according to the present embodiment will be described as an example of application to a single-lens reflex digital camera capable of exchanging lenses.

(Embodiment 1)
FIG. 1 is a central longitudinal front view showing an outline of the internal structure of the camera body of the single-lens reflex digital camera of Embodiment 1, and FIG. 2 is a longitudinal view on the lens optical axis showing the outline of the internal structure. FIG. 3 is a side view, and FIG. 3 is a horizontal sectional view on the optical axis of the lens showing the outline of the internal structure.

  The single-lens reflex digital camera 1 according to Embodiment 1 includes a camera body 10 and a photographing lens 11 that is mounted on the front side of the camera body 10 so as to be replaceable. A resin-made camera body 10 constituting the external shape of the camera 1 is a ring-shaped mount for removably mounting a lens unit 12 including the photographic lens 11 on the front surface side position on the optical axis O of the photographic lens 11. The unit 13 is provided. Further, the camera body 10 has a grip portion 14 that is held by the right hand of the operator at the time of shooting or the like on the left side when viewed from the front side. Various switches such as a release switch and buttons are provided on the top of the grip portion 14.

  As shown in FIGS. 2 and 3, the camera body 10 includes a liquid crystal monitor 17 as a display device having an acrylic panel display window 16 at a position on the optical axis O on the back side. The liquid crystal monitor 17 is a TFT (Thin Film Transistor) type rectangular display panel that displays various information such as various settings and adjustment items in addition to the photographed image. The camera body 10 is provided with a finder window 18 through which an operator peeks at the time of shooting, and a hot shoe 19 to which an external flash is attached at the top.

  As shown in FIG. 2, the camera body 10 incorporates a mirror member such as a quick return mirror 20 disposed on the optical axis O on the front side, and an AF sensor unit for detecting the defocus amount below the mirror member. A mirror box 22 containing 21 etc. is provided. Further, in the camera body 10, a focal plane shutter 23 and an imaging unit 25 including an imaging element 24 and the like are perpendicular to the optical axis O on the optical axis O toward the back side from the quick return mirror 20. Are arranged in order. In the camera body 10, a sub mirror 20 a is disposed behind the quick return mirror 20 on the optical axis O, and an optical path is set so that reflected light from the sub mirror 20 a is guided to the AF sensor unit 21. On the other hand, on the reflection side optical axis of the quick return mirror 20, a roof mirror 26, an eyepiece lens 27, and the like are arranged.

  Furthermore, a battery storage chamber 41 for storing the battery 40 is provided inside the grip portion 14 of the camera body 10. The battery 40 can be inserted into and removed from the battery storage chamber 41 by opening and closing an open / close lid 42 on the bottom surface. In addition, a circuit board 43 on which a circuit for controlling the entire camera, image processing, compression processing, data storage processing, a memory such as SDRAM, a power supply circuit, and the like are mounted on the back side inside the grip portion 14. , 44 are arranged. The circuit board 43 and the support plate 31 on which the image sensor 24 is mounted, and the circuit boards 43 and 44 are electrically connected by flexible boards 45 and 46. In the grip portion 14, a memory slot 48 for loading a memory card 47 is formed between the battery storage chamber 41 and the circuit board 44, and is normally closed with a cover 49 that can be opened and closed. In the grip portion 14, a strobe aluminum electrolytic capacitor 50 is built in front of the battery storage chamber 41.

  Here, the imaging unit 25 includes an optical LPF (low-pass filter) 30, an imaging element 24, and a support plate 31. The imaging element 24 photoelectrically converts a subject image formed on the imaging surface by the photographing lens 11 and has a horizontally long rectangular shape with a predetermined ratio. In the first embodiment, for example, a CCD image sensor is used. . The image sensor 24 is not limited to a CCD image sensor, and may be a CMOS image sensor or the like. The support plate 31 is for mounting and fixing and positioning the image sensor 24 on the surface. The support plate 31 is made of a heat radiating material such as a metal having good heat radiating property, and is made of an aluminum plate in the first embodiment, and is formed in a horizontally elongated substantially rectangular shape larger than the image sensor 24.

  The imaging unit 25 further includes a first holding member 51, a second holding member 52, a fixing member 53, and a drive mechanism 60. The first holding member 51 is formed in a rectangular frame shape and holds the support plate 31 and the optical LPF 30 on which the image sensor 24 is mounted. The second holding member 52 is formed in a rectangular frame shape that is slightly larger than the first holding member 51, and holds the first holding member 51 so as to be movable in the Y-axis direction (vertical direction). It is. Here, between the first holding member 51 and the second holding member 52, two steel balls that are spaced apart so as to be movable only in the Y-axis direction on one side in the X-axis direction (left-right direction). The first holding member 51 can be smoothly moved in the Y-axis direction with respect to the second holding member 52 by interposing one steel ball 54b on the other side. A spring 55 is interposed between the first holding member 51 and the second holding member 52 in the vicinity of the steel ball 54b.

  The fixing member 53 is formed in a rectangular frame shape that is slightly larger than the second holding member 52, and is for holding the second holding member 52 so as to be movable in the X-axis direction. Here, between the second holding member 52 and the fixing member 53, two steel balls 56a that are arranged to be movable only in the X-axis direction on one side in the Y-axis direction, and 1 on the other side. By interposing the individual steel balls 56 b, the second holding member 52 can move smoothly in the X-axis direction with respect to the fixing member 53. A spring 57 is interposed between the second holding member 52 and the fixing member 53 in the vicinity of the steel ball 56b. In addition, the fixing member 53 is assembled to the fixing unit such as the mirror box 22 at four positions so that the imaging element 24 is positioned on the optical axis O, for example. Here, in the fixing member 53, a fixed heat radiating plate 58 formed larger than the support plate 31 is integrated by screwing at a position close to and opposed to the back surface of the support plate 31. That is, the fixed heat sink 58 also constitutes a part of the fixed member. The fixing member 53 and the fixed heat radiation plate 58 are made of a material such as a metal having a good heat dissipation property or a PC resin (polycarbonate resin) or a PPS resin (polyphenylene sulfide resin) filled with a filler such as carbon fiber as a material having high thermal conductivity. ).

  The drive mechanism 60 includes a first drive mechanism 61 and a second drive mechanism 62. The first drive mechanism 61 is provided between the first holding member 51 and the second holding member 52 so as to correspond to the steel ball 54 a portion, and the first holding member 51 is used as the second holding member 52. On the other hand, it is for moving the displacement in the Y-axis direction. For example, the first drive mechanism 61 is provided in the second holding member 52 side by being brought into press contact with the first holding member 51 and generates an elliptical vibration by applying a voltage to a driving electrode (not shown). This holding member 51 is configured as a piezoelectric element drive motor system using a piezoelectric element 61a that moves the second holding member 52 in the Y-axis direction (see FIG. 3).

  The second drive mechanism 62 is provided between the second holding member 52 and the fixing member 53 so as to correspond to the steel ball 56 a portion, and moves the second holding member 52 in the X-axis direction with respect to the fixing member 53. It is for moving the displacement. The second drive mechanism 62 is also provided in the fixed member 53 side by being brought into press contact with the second holding member 52, for example, and generates an elliptical vibration by applying a voltage to a drive electrode (not shown). This is configured as a piezoelectric element drive motor system using a piezoelectric element 62a that moves 52 in the X-axis direction with respect to the fixed member 53 (see FIG. 2).

  The drive mechanism 60 is not limited to the piezoelectric element drive motor system, but may be an electromagnetic drive system, a system that drives a flexural vibration motor as a drive source, or a system that uses a VCM (voice coil motor) as a drive source. Good.

  By providing such a drive mechanism 60, the support plate 31 on which the image sensor 24 is mounted can be displaced in a two-dimensional direction that is up, down, left, and right within the XY plane perpendicular to the optical axis O with respect to the fixing member 53. Become. Therefore, when camera shake occurs in the single-lens reflex digital camera at the time of photographing, the light receiving surface of the image sensor 24 is driven by driving the driving mechanism 60 and moving the support plate 31 in the two-dimensional direction in the XY plane. It is possible to correct image blur in

  Here, the imaging unit 25 of the present embodiment further includes a movable heat radiating plate 71, a guide shaft 72, a compression coil spring 73, and an electromagnetic drive mechanism 80. FIG. 5 is a horizontal cross-sectional view of the optical axis portion showing a part of the imaging unit 25 when the electromagnetic drive mechanism 80 is de-energized and energized, and FIG. 6 is a longitudinal side view of the optical axis portion. It is. First, the two guide shafts 72 as guide members are erected so as to be positioned near both ends of the fixed heat radiating plate 58 in the X-axis direction and project toward the support plate 31 side. Further, the movable heat radiating plate 71 is disposed on the side of the fixed heat radiating plate 58 facing the support plate 31 and is slidably fitted to the guide shaft 72 so as to be guided and moved in the direction of the optical axis O. ing. Here, the guide shaft 72 is made of a heat radiating material, and the fixed heat radiating plate 58 and the movable heat radiating plate 71 are always thermally coupled. The compression coil spring 73 as an elastic member is provided between the E-ring 74 fixed on the tip end side of the guide shaft 72 on the guide shaft 72 and the movable heat radiating plate 71, and the movable heat radiating plate 71 is fixed to the fixed heat radiating plate. This is for biasing to the 58 side.

  The electromagnetic drive mechanism 80 as an energization drive mechanism is composed of a combination of a magnetic core 82 around which an excitation coil 81 is wound and a rubber magnet 83. When the excitation coil 81 is energized, the movable heat dissipation plate 71 is provided. An electromagnetic solenoid system that generates an electromagnetic attractive force as a driving force to be moved is provided at a plurality of locations, for example, 6 locations, distributed almost evenly. Here, the magnetic core 82 is formed in a cylindrical shape from a heat radiating material, and its axial center is disposed on the movable heat radiating plate 71 along the optical axis O. It also serves as a heat conduction part.

  The rubber magnet 83 having a low magnetic force as a permanent magnet is disposed on the back side of the support plate 31 so as to face each magnetic core 82 on a heat conductive member 75 integrally provided with an adhesive having high heat conductivity. ing. The magnetic flux of the rubber magnet 83 is set in a direction perpendicular to the surface of the movable heat radiating plate 71. Thereby, when the exciting coil 81 is energized, an electromagnetic attractive force is generated between the magnetic core 82 and the rubber magnet 83, and both are brought into contact with each other. Here, the electromagnetic attractive force is set to be weaker than the driving force by the driving mechanism 60 described above. Further, the rubber magnet 83 has a heat dissipation property and is formed in a plate shape larger than the magnetic core 82 that contacts and separates. With respect to such a rubber magnet 83, if there is a possibility that the magnetic force is reduced by heat during injection molding, the rubber magnet 83 may be used with the magnetic force of the rubber magnet obtained after the injection molding. Alternatively, the flexible rubber magnet 83 may be magnetized after injection molding. The permanent magnet is not limited to the rubber magnet 83, and may be a flexible magnet such as a plastic magnet, or may be a rare earth magnet such as SmCO.

  FIG. 7 is a horizontal sectional view showing in principle a more detailed configuration example around the fixed heat radiating plate 58 and the movable heat radiating plate 71. A circuit board 90 formed by etching a printed board or a copper plate is provided on the surface of the movable heat radiating plate 71, and a power supply signal line portion on the circuit board 90 is soldered to each excitation coil 81. In addition, a plurality of heat radiation passages 91 are formed around the magnetic cores 82 in the movable heat radiation plate 71, and a heat radiation sheet 92 is highly thermally conductive on the back side of the movable heat radiation plate 71. A plurality of heat dissipating fins 93 are provided at an opposing portion of the heat dissipating sheet 92 and the fixed heat dissipating plate 58 to improve heat dissipation. Further, a heat radiation passage 94 is formed in a portion of the fixed heat radiation plate 58 facing the magnetic core 82. The base side of each magnetic core 82 is thermally connected and fixed to the shield plate 96 of the liquid crystal monitor 17 with a small screw 97 by a wire member 95 such as a lead wire. Here, a heat conductive sheet 98 having high heat conductivity such as a graphite sheet is interposed between the fixed heat radiating plate 58 and the shield plate 96. Therefore, the wire member 95 is provided so as to be laminated or embedded in the heat conductive sheet 98.

  A temperature sensor 99 for detecting the temperature in the vicinity of the image sensor 24 is soldered and mounted on the circuit board 90 on the surface of the movable heat radiating plate 71. The temperature sensor 99 may be omitted when a temperature sensor is provided in a hall element (not shown) for detecting the position of the image sensor 24. Further, the temperature sensor may be disposed between the fixed heat radiating plate 58 and the shield plate 96. In this case, it may be provided so as to be laminated or embedded in the heat conductive sheet 98.

  A plurality of heat conductive members 76 are formed on the heat conductive member 75 on the support plate 31 so as to protrude toward the movable heat radiating plate 71. The heat conductive member 76 is formed by an etching method in order to obtain cushioning properties. That is, the heat conductive member 76 is formed as a cylindrical member having a diameter of 0.5 mm at a predetermined interval on a metal heat conductive member 75 (a thin plate of 0.5 mm thick copper material) by an etching method. . Alternatively, as the thermal conductive member 76, a PPS resin material filled with graphite or aluminum powder having high thermal conductivity may be formed by injection molding or the like.

  Alternatively, as the heat conductive member 76, heat conduction such as λ gel (registered trademark) formed in a columnar shape so as to have flexibility to follow the displacement movement of the support plate 31 in the two-dimensional direction. It is made of a flexible material, a plurality of which are joined to the support plate 31, and are vertically and horizontally uniform between the support plate 31 and the movable heat sink 71 made of PPS resin material filled with graphite or aluminum powder having high thermal conductivity. It may be distributed so that In the first embodiment, as shown in FIG. 4, a heat dissipation sheet 31 a to which one end of a plurality of heat conductive members 76 is attached is provided, and the other end of the plurality of heat conductive members 76 is a movable heat dissipation plate 71. The heat conductive member 76 is loaded by attaching the heat radiating sheet 31a on the support plate 31 so as to be in contact with or away from the surface of the support plate 31.

  In any case, the heat conductive member 76 needs to have a columnar body whose height is about the height of the magnetic core 82. Furthermore, the outer shape of the columnar body can also be formed in a spiral shape standing in order to improve heat dissipation or an S-shape that lies sideways. Therefore, the height of the columnar body of the heat conductive member 76 is more preferably a PPS resin sheet filled with graphite or aluminum powder having a high heat conductivity of about 1.5 mm.

  In such a configuration, the image sensor 24 becomes a main heat source in the camera body 10, and heat is generated as the image sensor 24 is driven. As a result, when the temperature sensor 99 detects that the temperature in the vicinity of the image sensor 24 has risen above a predetermined temperature, the exciting coil 81 is energized by a control system described later. When the exciting coil 81 is energized, an electromagnetic attractive force is generated between the magnetic core 82 and the rubber magnet 83 that are separated from each other, and the fixed heat dissipation is performed so that the tip of the magnetic core 82 contacts the rubber magnet 83. The movable heat radiating plate 71 is moved against the compression coil spring 73 while being guided by the guide shaft 72 with respect to the plate 58. Thereby, as shown in FIG. 5B and FIG. 6B, the tip of the magnetic core 82 comes into contact with the rubber magnet 83. Although an impact sound is likely to occur at the time of this contact, in Embodiment 1, since the rubber magnet 83 is used as a permanent magnet, the impact at the time of contact with the magnetic core 82 is suppressed, and the impact sound can be eliminated. it can. Further, the front end side of the heat conductive member 76 is also in contact with the movable heat radiating plate 71.

  Thereby, after the heat generated by the image sensor 24 is transmitted to the support plate 31 having heat dissipation properties, the heat conductive member 75, the rubber magnet 83, the magnetic core 82, the movable heat dissipation plate 71 having high heat conductivity, It is transmitted to the guide shaft 72, the fixed heat radiation plate 58, and the fixed member 53 side. At this time, heat can be transmitted to the fixed heat radiating plate 58 and the fixed member 53 side more efficiently by transmitting heat by the members 75, 83, 82, 71, 72 having heat dissipation rather than transmitting the air layer. . The heat conducted to the magnetic core 82 is further transmitted to the shield plate 96 of the liquid crystal monitor 17 through the wire member 95, and is efficiently radiated without heat stagnating in the magnetic core 82 portion. Furthermore, since the heat conductive member 76 is in contact with the movable heat radiating plate 71, the heat on the support plate 31 side is the heat conductive member 76, the movable heat radiating plate 71, the guide shaft 72, the fixed heat radiating plate 58, the fixed member. The heat is also efficiently radiated by the route on the 53 side.

  By the way, the support plate 31 on which the image pickup device 24 is mounted is displaced in the Y direction or the X direction when the camera shake correction is performed by the drive mechanism 60. Here, in the first embodiment, the electromagnetic attractive force in the electromagnetic drive mechanism 80 is set to be weaker than the drive force of the drive mechanism 60, and the magnetic core 82 even when the electromagnetic drive mechanism 80 is energized. Is merely in contact with the rubber magnet 83, and the rubber magnet 83 can be slidably displaced with respect to the magnetic core 82, so that the camera shake correction operation is not impaired. Further, even when the heat conductive member 76 is in contact with the movable heat radiating plate 71, the heat conductive member 76 is made of a heat conductive flexible material formed in a cylindrical shape and follows the displacement movement of the support plate 31. Therefore, the camera shake correction operation is not impaired. Therefore, even in a state where the temperature in the vicinity of the image pickup device 24 is increased, the magnetic core 82 is in contact with the rubber magnet 83, and the heat conductive member 76 is in contact with the movable heat sink 71 to exert a heat transfer effect. An image stabilization operation can be executed.

  For example, FIG. 5B shows a case where the support plate 31 (image sensor 24) is displaced by ΔX in the X direction by the second drive mechanism 62. In this case, the rubber magnet 83 slides and displaces in the X direction with respect to the magnetic core 82. However, since the rubber magnet 83 is formed to be large, the contact state between the two can be maintained and the heat dissipation effect can be exhibited. Further, since the heat conductive member 76 is formed of a flexible material in a columnar shape and easily deforms, the heat conductive member 76 is inclined in the X direction following the displacement movement of the support plate 31, and the back surface side of the support plate 31 and the movable heat radiating plate. The contact state with 71 is maintained. In this way, there is no problem with the displacement movement of the support plate 31 during camera shake correction.

  FIG. 6B shows a case where the first driving mechanism 61 moves the support plate 31 (imaging element 24) by ΔY in the Y direction. In this case, the rubber magnet 83 slides and displaces in the Y direction with respect to the magnetic core 82. However, since the rubber magnet 83 is formed larger, it is possible to maintain the contact state between them and to exert a heat radiation effect. Further, since the heat conductive member 76 is formed of a flexible material in a cylindrical shape and easily deforms, the heat conductive member 76 is inclined in the Y direction following the displacement movement of the support plate 31, and the back surface side of the support plate 31 and the movable heat radiating plate. The contact state with 71 is maintained. In this way, there is no problem with the displacement movement of the support plate 31 during camera shake correction.

  When the temperature of the image sensor 24 is not increased and the electromagnetic drive mechanism 80 is not energized, no electromagnetic attractive force is generated, and the magnetic core 82 is removed from the rubber magnet 83 by the spring force of the compression coil spring 73. Since they are separated from each other, there is no hindrance to the displacement movement of the support plate 31 at the time of camera shake correction. It can also be used for the positioning function of the image sensor 24 when the electromagnetic drive mechanism 80 is not energized or when the live view operation shown in FIG. 11 is started. In the case of an electromagnetic drive mechanism that uses an exciting coil or permanent magnet for camera shake correction, there is a problem regarding low power consumption by always supplying current. However, for such a problem, the image sensor 24 moves. If not, it can wait at the initialization position (position of the image sensor 24 when the power is turned on) and can be magnetically locked. In addition, a taper hole is formed in a support member such as the support plate 31 for the image sensor 24, and a taper pin corresponding to the taper hole is provided on the movable heat radiating plate 71 side. It is also possible to mechanically lock by engaging.

  Here, with or without a heat conductive member (magnetic body 82, rubber magnet 83, movable heat sink 71, guide shaft 72, heat conductive member 76, etc. are shown together) and heat conductive sheet 98 are provided. The difference in the heat radiation effect will be described with reference to FIG. FIG. 8A is a thermal circuit configuration diagram illustrating the case of the first embodiment, and FIG. 8B includes a heat conductive member, a heat conductive sheet 98, and a fixed heat radiating plate 58. It is a thermal circuit block diagram which models and shows the conventional case which is not. In FIG. 8, fine parts such as a motor are collectively shown as one thermal resistance. Further, when the entire camera is modeled, the amount becomes enormous, so in FIG. 8, only the thermal circuit on the optical axis O from the imaging unit 25 to the panel display window 16 is shown. In FIG. 8, each component indicated by a circled numeral is 1 for the optical LPF 30, 2 for the image sensor 24, 3 for the support plate 31, 4 for the first drive mechanism 61, and 5 for the second holding member 52. , 6 is the second drive mechanism 62, 7 is the fixing member 53, 8 is the shield plate 96, 9 is the liquid crystal monitor 17, 10 is inside the acrylic panel display window 16, 11 is outside the acrylic panel display window 16, Reference numeral 12 denotes a fixed heat radiating plate 58, 13 is the outside of the shield plate 96.

  First, in the conventional case that does not include the heat conductive member, the heat conductive sheet 98, or the fixed heat radiating plate 58, as shown in FIG. In addition to the optical LPF 30 and the part that radiates heat through the air layer, most of the heat is transferred to the aluminum support plate 31, and then the liquid crystal monitor 17 passes through the air layer between the support plate 31 and the shield plate 96. The heat is transferred to the side and further radiated to the outside through the air layer and the panel display window 16 made of acrylic. That is, there are many parts depending on the air layer having a large thermal resistance, and the heat dissipation efficiency is poor.

  On the other hand, in the case of the first embodiment, as shown in FIG. 8A, the heat of the image sensor 24 serving as a heat generation source is other than the air layer, the optical LPF 30, and the part that is radiated through the air layer. After the heat is transferred to the aluminum support plate 31, first, the heat is efficiently transferred to the fixed heat radiating plate 58 side through the heat conductive member, and further, the heat transferred to the fixed heat radiating plate 58 and the fixed member 53. Is efficiently transferred to the shield plate 96 via the heat conductive sheet 98. The heat transmitted to the shield plate 96 is radiated to the outside as it is, or is transmitted to the liquid crystal monitor 17 side, and further radiated to the outside through the air layer or the acrylic panel display window 16. As described above, according to the first embodiment, the heat generated in the image sensor 24 can be efficiently transferred to the fixed heat radiating plate 58 and the liquid crystal monitor 17 side to be radiated as compared with the conventional example. .

  Next, the configuration of the electrical control system of the single-lens reflex digital camera according to the first embodiment including such components will be described. FIG. 9 is a block diagram illustrating a configuration example of the electrical control system of the single-lens reflex digital camera according to the first embodiment. First, a system controller 100 that controls the entire camera is provided. The system controller 100 includes a CPU 101 and a plurality of circuit blocks such as an image processing circuit 102, a compression / decompression circuit 103, an external memory IF circuit 104, an interrupt control circuit 105, a timer counter 106, an AD converter 107, and the like. The CPU 101 and each of the circuit blocks 102 to 107 are connected by a control line or a bus line.

  The image processing circuit 102 performs predetermined image processing such as γ correction, color conversion, pixel conversion, and white balance processing on the image data captured by the image sensor 24 in the imaging unit 25 and captured from the image sensor IF circuit 110. Apply. The compression / decompression circuit 103 performs compression processing of the image data processed by the image processing circuit 102 and expansion processing of the compressed image data read from the memory card 47.

  The external memory IF circuit 104 performs a bridge function between the memory card 47, the SDRAM 111, the FlashRom 112, and the data bus inside the system controller 100. In the FlashRom 112, a control program for controlling the entire operation, a control parameter, and the like are recorded. In the system controller 100, the CPU 101 reads out and executes a control program stored in the FlashRom 112, thereby controlling the operation of the camera and realizing a function as a control unit. The SDRAM 111 is used for temporary storage of image data obtained via the image sensor IF circuit 110 and as a work area for the system controller 100. The memory card 47 is a removable recording medium such as a semiconductor nonvolatile memory or a small HDD.

  The interrupt control circuit 105 generates an interrupt signal from the camera operation switch 113, an interrupt signal from the timer counter 106, and the like. The timer counter 106 counts clocks and generates timing signals necessary for system control. The AD converter 107 A / D converts detection outputs of various sensors such as the temperature sensor 99 provided in the camera body 10.

  The image sensor 24 provided in the imaging unit 25 photoelectrically converts the subject image formed by the photographing lens 11 into an analog electric signal. The image sensor IF circuit 110 generates a timing pulse for driving the image sensor 24, reads an analog electric signal photoelectrically converted by the image sensor 24, performs AD conversion, and transfers it to the system controller 100 as image data.

  The temperature sensor 99 constitutes temperature detecting means together with the temperature detecting circuit 114. As the temperature sensor, an element whose resistance value changes according to temperature or a semiconductor temperature sensor may be used. The temperature sensor 99 is for detecting the temperature in the vicinity of the image sensor 24 as described above.

  The dustproof filter drive circuit 115 outputs a drive signal to a piezoelectric element (not shown) in order to remove dust attached to a dustproof filter (not shown) included in the imaging unit 25 by vibration. The drive mechanism 60 is for two-dimensionally displacing the image sensor 24 in an XY plane perpendicular to the optical axis O of the photographic lens 11, and includes an actuator that is a piezoelectric element drive motor as a drive source. The actuator drive circuit 116 outputs a drive signal to this actuator. The system controller 100 can execute a so-called camera shake correction operation that prevents the image from being deteriorated by displacing the image sensor 24 in accordance with camera shake. Camera shake is detected by an angular velocity sensor 117a using a gyroscope and an angular velocity detection circuit 117 that amplifies the output of the angular velocity sensor 117a. The system controller 100 outputs a control signal for shake correction operation to the actuator drive circuit 116 based on the output of the angular velocity detection circuit 117.

  A focal plane shutter 23 provided on the front surface (subject side) of the image pickup unit 25 and controlling the exposure time of the image pickup device 24 is driven to open and close by a shutter drive mechanism 118. The system controller 100 controls the opening / closing operation by the shutter drive mechanism 118 by the actuator drive circuit 116 according to the exposure time. The quick return mirror 20 can be switched between a down position (Down position) positioned on the optical path of the photographing lens 11 and an up position (Up position) positioned outside the optical path by the mirror drive mechanism 119. The central portion of the quick return mirror 20 is in a semi-transmissive state, and when the quick return mirror 20 is in the down position, the light flux of the photographing lens 11 is divided into the pentaprism 26 side and the sub mirror 20a side. The sub mirror 20a is disposed on the back surface side of the quick return mirror 20, and is folded when the quick return mirror 20 is in the up position, and transmits light transmitted through the center of the quick return mirror 20 when the quick return mirror 20 is in the down position. Reflected to the AF sensor 21. Further, a part of the light beam that has passed through the pentaprism 26 is guided to a photometric sensor (not shown) in the photometric circuit 120, and a known photometric process is performed based on the amount of light detected here.

  The power supply circuit (DC / DC converter) 121 converts the voltage of the battery 40 into a drive voltage necessary for the system controller 100 and its peripheral circuits and supplies the converted drive voltage. The power distribution is controlled based on a command from the system controller 100. The liquid crystal monitor drive circuit 122 drives the liquid crystal monitor 17. The liquid crystal monitor 17 displays image data at the time of the live view operation or various menus according to the drive signal from the liquid crystal monitor drive circuit 122. The camera operation switch 113 is a switch for operating the camera, and includes a release switch, a mode setting switch, a finder mode switching switch, an image stabilization mode switching switch, a power switch, and the like.

  Further, the suction actuator drive circuit 123 is for supplying a drive current to the excitation coil 81 in the electromagnetic drive mechanism 80 provided in the imaging unit 25. When a current flows through the exciting coil 81, an electromagnetic attractive force is generated between the magnetic core 82 and the rubber magnet 83.

  The taking lens 11 in the lens unit 12 is controlled by a lens controller 130. The lens controller 130 is connected to the system controller 100 via a communication line, and executes a predetermined control operation in response to a command from the system controller 100.

  Subsequently, prior to description of an example of operation control executed by the CPU 101 in the system controller 100, an outline of temperature control in the first embodiment will be described. FIG. 10 is a graph showing the correspondence between the detected temperature T near the image sensor 24 and the camera control operation. The temperature determination values T1 to T4 have a magnitude relationship of T1 <T2 <T3 <T4. These determination values T1 to T4 are control parameters stored in the FlashRom 112.

  Here, it is assumed that the power switch is turned on and the camera operation starts from a state where the temperature of the image sensor 24 is sufficiently low. Then, assume that the user selects a live view operation, for example. Then, since the image sensor 24 operates continuously, the temperature T near the image sensor 24 rises. Therefore, as shown at time t1, when the detected temperature T exceeds the determination value T2, the display rate of the liquid crystal monitor 17 is changed from 30 fps to 15 fps. By lowering the display rate, the temperature rise of the image sensor 24 is suppressed.

  However, in some cases, such as when the outside temperature of the camera is high, the temperature rise of the image sensor 24 cannot be suppressed. Then, as shown at time t2, when the detected temperature T exceeds the determination value T3, excitation is performed by the adsorption actuator driving circuit 123 in order to efficiently release the heat of the image sensor 24 while the display rate is lowered. The coil 81 is energized to attract the magnetic core 82 to the rubber magnet 83. By this adsorption operation, the heat generated in the image sensor 24 can be released to the fixed heat radiating plate 58 side or the liquid crystal monitor 17 side via the movable heat radiating plate 71.

  Normally, the temperature rise of the image sensor 24 is stopped by the two temperature rise prevention operations (display rate changing operation and heat dissipation operation by energizing the exciting coil 81), and the temperature gradually decreases. Therefore, as shown at time t3, when the detected temperature T falls below the determination value T1, the display rate of the liquid crystal monitor 17 is changed from 15 fps to 30 fps, the excitation coil 81 is deenergized, and the adsorption operation is released. Two temperature rise prevention operations stop. Note that the temperature rise prevention operation is not stopped until the temperature rises below the judgment value T2 because the temperature T is in the vicinity of the judgment value T2 when the start and stop of the temperature rise prevention operation are controlled based on the judgment value T2. This is because the operation becomes unstable when it is in the area, and a dead zone region is secured.

  In addition, as shown at time t4, when two temperature rise prevention operations are executed, the temperature rise of the image sensor 24 does not stop and the situation exceeds the determination value T4. Forcibly stop the operation.

  In the above description, it is assumed that the temperature of the image sensor 24 increases with the live view operation. However, even when the user does not select the live view operation, the continuous shooting operation (for example, in the continuous shooting mode). The temperature of the image sensor 24 can similarly rise when the user executes the operation of keeping the release switch pressed. Even in such a case, the above-described two temperature rise prevention operations are executed.

  Next, an example of camera operation control including a temperature rise prevention operation, a camera shake correction operation, and the like executed by the CPU 101 in the system controller 100 will be described. 11 to 13 are schematic flowcharts showing an example of camera operation control executed by the CPU 101. First, when the power switch of the camera 1 is turned on, the system of the camera 1 is initialized (step S100). Next, it is determined whether or not a finder mode changeover switch, which is one of the camera operation switches 113, has been operated by the user (step S102). By operating this switch, the finder mode changeover switch can select the optical finder mode and the live view mode as the finder mode. The optical finder mode is a mode in which the subject image formed by the photographing lens 11 is directly observed through the finder window 18. On the other hand, in the live view mode, the subject image formed by the photographing lens 11 is acquired as image data using the imaging device 24 and displayed on the liquid crystal monitor 17 so that the user can use the liquid crystal monitor 17 to display the subject image. This is an observation mode.

  When the operation of the finder mode changeover switch is detected (step S102; Yes), the currently set finder mode state is determined (step S104). If the live view mode has been set, the optical viewfinder mode is set (step S106), the quick return mirror 20 is set to the down position for the optical viewfinder mode, and the live view operation is stopped (step S108). On the other hand, if the optical viewfinder mode has been set, the live view mode is set (step S110), the quick return mirror 20 is set to the up position for the live view mode, and the live view operation is started (step S112). ). When the operation of the finder mode changeover switch is not detected (step S102; No), the process proceeds to step S120.

  Subsequently, it is determined whether or not the image stabilization mode switch, which is one of the camera operation switches 113, has been operated by the user (step S120). The anti-vibration mode changeover switch is for selecting permission or prohibition of the camera shake correction operation by operating this switch. When the camera shake correction operation is permitted, the camera shake correction operation is performed during the exposure operation or the live view operation by operating the drive mechanism 60. When the operation of the image stabilization mode switch is detected (step S120; Yes), it is determined whether or not the image stabilization mode is currently set (step S122). If the image stabilization mode is not set (step S122; No), the image stabilization mode is set (step S123). As a result, the camera shake correction operation is performed during the exposure operation or the live view operation. On the other hand, when the image stabilization mode is set (step S122; Yes), the image stabilization mode is canceled (step S124). Thereby, the camera shake correction operation during the exposure operation or the live view operation is prohibited. If the operation of the image stabilization mode switch is not detected (step S120; No), the process proceeds to step S125.

  Further, in the first embodiment, when the camera 1 falls, an operation for protecting the imaging unit 25 from an impact applied to the camera 1 is performed. First, it is determined whether or not the camera 1 is in a fall state (step S125). This process determines whether or not the camera 1 is in a fall state by periodically monitoring the output of the angular velocity sensor 117a. If not in the falling state (step 125; No), the process proceeds to step S130.

  On the other hand, if the camera 1 is in a fall state (step S125; Yes), an operation (impact mitigation operation) is performed to protect the movable part inside the camera 1 from an impact that occurs when the camera 1 falls and collides with the ground. (Step S126). As the impact relaxation operation, a centering operation of the image sensor 24 by the drive mechanism 60 and an adsorption operation accompanying energization of the excitation coil 81 by the electromagnetic drive mechanism 80 are executed. The imaging element 24 (imaging unit 25) is positioned at the center of the movement range by the centering operation. Further, by energizing the exciting coil 81 to attract the magnetic core 82 and the rubber magnet 83, the imaging unit 25 is prevented from moving carelessly due to an impact at the time of collision. And it waits until the camera 1 falls and collides with the ground (step S127), and when it collides and is stabilized (step S127; Yes), it transfers to step S202 and stops operation | movement of a system.

  Subsequently, the temperature in the vicinity of the image sensor 24 is detected by the outputs of the temperature sensor 99 and the temperature detection circuit 114, the measured temperature data Tx and the threshold values (predetermined determination values T1 to T4) are compared, and the comparison result In response to this, the process branches to a predetermined operation step (step S130). First, when T3 ≧ Tx> T2 (corresponding to time t1 in FIG. 10), it is determined whether or not the live view mode is performed at a frame rate of 30 fps (step S136). If present (step S136; Yes), the live view mode frame rate is changed to 15 fps (step S138). Due to such a decrease in the frame rate, heat generated by the image sensor 24 is suppressed.

  If T4 ≧ Tx> T3 (corresponding to time t2 in FIG. 10), it is determined whether or not the magnetic core 82 is attracted to the rubber magnet 83 (step S132). If not attracted (step S132; No), a control signal is sent to the attracting actuator drive circuit 123 to energize the exciting coil 81, thereby attracting the magnetic core 82 to the rubber magnet 83 (step S134) to dissipate heat. Secure a route.

  Further, if T1 ≧ Tx (corresponding to time t3 in FIG. 10), it is determined whether or not the live view mode is performed at the frame rate of 15 fps (step S140). (Step S140; Yes), the frame rate of the live view mode is changed to 30 fps (Step S142). This is because if the temperature in the vicinity of the image sensor 24 is sufficiently lowered, there is no problem even if the frame rate in the live view operation is returned to the normal 30 fps. Further, it is determined whether or not the magnetic core 82 is attracted to the rubber magnet 83 (step S144). If it is attracted (step S144; Yes), a control signal is sent to the attracting actuator drive circuit 123 to stop energization of the exciting coil 81, thereby canceling the attracting between the magnetic core 82 and the rubber magnet 83. (Step S146), the spring is separated by the spring force of the compression coil spring 73. This is because if the temperature in the vicinity of the image sensor 24 is sufficiently lowered, a heat radiation operation in the heat radiation path using the magnetic core 82 or the like is not necessary.

  If Tx> T4 (corresponding to time t4 in FIG. 10), the process proceeds to step S202 to stop the operation of the system.

  Thereafter, in step S150, it is determined whether or not the release switch in the camera operation switch 113 is in the 1st release switch ON state. When the release switch is half-pressed, the 1st release switch is turned on. If it is not in the 1st release switch ON state (step S150; No), it is determined whether or not the power switch is in the ON state (step S200). If it is in the ON state (step S200; Yes), the process returns to step S102. If the power switch is not in the ON state (step S200; No), the system operation is stopped (step S202), and the process is terminated.

  On the other hand, if the first release switch is ON (step S150; Yes), it is determined whether or not the live view mode and the image stabilization mode are set (step S152). When both these two modes are set (step S152; Yes), the blur correction operation is started by driving the drive mechanism 60 via the actuator drive circuit 116 (step S154). By this operation, the user can observe the subject image on the liquid crystal monitor 17 in a stable state. If the above two modes are not set (step S152; No), the process of step S154 is jumped.

  Thereafter, a shooting preparation operation is performed in accordance with the 1st release switch ON state (step S156). The shooting preparation operation includes an automatic focus adjustment operation (AF) and an operation (AE) for measuring subject brightness and determining an exposure condition. Here, when the live view mode is set, the contrast value is detected from the output of the image sensor 24, and the position of the photographing lens 11 is set to the position where the contrast value is maximized (contrast AF operation). . Further, the subject brightness is measured from the output of the image sensor 24. On the other hand, when the optical finder mode is set, a defocus value (a focus shift amount) is detected from the output of the AF sensor in the AF sensor unit 21, and the photographing lens 11 is driven based on the detected value ( Phase difference AF operation). Also, the subject brightness is measured from the output of the photometry circuit 120.

  In this way, when the shooting preparation operation is completed, it is determined whether or not the release switch is in the 2nd release switch ON state (step S158). When the release switch is fully pressed, the 2nd release switch is turned on. Here, if the 2nd release switch is not in the ON state (step S158; No), it is determined whether or not the 1st release switch is in the ON state (step S190). If the 1st release switch is in the ON state (step S190; Yes), it indicates that the user is maintaining the focus lock state and waits for the 2nd release switch to be in the ON state. However, when the ON state of the first release switch is released (step S190; No), the focus lock state is also released, and it is determined whether or not the shake correction operation is being performed (step S192). If the motion compensation operation is in progress (step S192; Yes), the motion compensation operation is stopped by stopping the operation of the drive mechanism 60 via the actuator drive circuit 116, and then the centering operation is performed to center the image sensor 24. Position to the position (step S194), and return to step S102.

  On the other hand, when the 2nd release switch is turned on (step S158; Yes), it is determined whether or not the shake correction operation is being performed (step S160). If the motion compensation operation is in progress (step S160; Yes), the motion compensation operation is stopped by stopping the operation of the drive mechanism 60 via the actuator drive circuit 116 (step S162). If the shake correction operation is not in progress (step S160; No), the process of step S162 jumps.

  Next, the finder mode being set is determined (step S164). Here, if it is the live view mode, the live view operation is stopped (step S166). On the other hand, if the mode is the optical finder mode, the quick return mirror 20 is driven to the up position (step S168).

  Further, it is determined whether or not the image stabilization mode is set (step S170). If the image stabilization mode is set (step S170; Yes), the blur correction operation is started after the centering operation for positioning the image sensor 24 at the center of the movement range is executed (step S174). That is, the shake amount of the camera 1 is detected from the angular velocity sensor 117a, and the image pickup device 24 is moved by driving the drive mechanism 60 via the actuator drive circuit 116 based on the shake amount. This operation is maintained during the exposure operation. If the image stabilization mode is not set (step S170; No), the process of step S174 jumps.

  Then, an exposure operation for exposing the image sensor 24 under a predetermined condition is performed. When the exposure operation is completed, an image acquisition operation is performed to read out image data from the image sensor 24, create a predetermined image file, and store it in the memory card 47. (Step S176). The exposure operation in this case is performed by controlling the focal plane shutter 23 and the aperture of the photographing lens 11 based on the exposure condition determined in step S156.

  When the photographing operation is finished, it is determined again whether or not the image stabilization mode is set (step S178). When the image stabilization mode is set (step S178; Yes), after stopping the shake correction operation, a centering operation for positioning the image sensor 24 at the center of the moving range is executed (step S182). If the image stabilization mode is not set (step S178; No), the process of step S182 jumps.

  Further, the finder mode being set is determined (step S184). Here, if it is the live view mode, the live view operation is resumed (step S188). On the other hand, if it is the optical finder mode, the quick return mirror 20 is driven to the down position (step S186).

  As described above, according to the first embodiment, when the temperature in the vicinity of the image sensor 24 rises to a predetermined temperature or more, the magnetic core 82 and the rubber magnet 83 are energized by energizing the excitation coil 81 of the electromagnetic drive mechanism 80. During this time, an electromagnetic attractive force is generated as a driving force to move the movable heat radiating plate 71 with respect to the fixed heat radiating plate 58, and the magnetic core 82 (heat conducting portion) of the movable heat radiating plate 71 is radiated for the image sensor 24. The heat transfer from the support plate 31 side to the fixed heat radiating plate 58 and the fixed member 53 side is efficiently performed by the magnetic core 82 (heat conducting portion) and the movable heat radiating plate 71 by contacting with the support plate 31 having the property. be able to. For this reason, the contact of the magnetic core 82 (heat conduction part) with the support plate 31 is realized without causing any trouble in the displacement movement on the support plate 31 side for preventing blurring and without complicating the structure. can do.

  In particular, in the first embodiment, the heat conducted to the magnetic core 82 is further transmitted to the shield plate 96 of the liquid crystal monitor 17 via the wire member 95, and the heat does not stagnate in the magnetic core 82 portion. It can dissipate heat well. Furthermore, since the heat conductive member 76 that does not hinder the displacement movement of the support plate 31 is also in contact with the movable heat radiating plate 71, the heat on the support plate 31 side is converted to the heat conductive member 76, the movable heat radiating plate. 71, the guide shaft 72, the fixed heat radiation plate 58, and the path on the fixed member 53 side can also efficiently dissipate heat.

  In the first embodiment, when the drive source of the shake preventing drive mechanism 60 is a VCM (voice coil motor), the magnetic core 82 and the rubber magnet 83 are turned off when the excitation coil 81 is turned off. And the movement of the image sensor 24 may be mechanically locked. That is, the attractive force between the magnetic core 82 and the rubber magnet 83 is made larger than the spring force of the compression coil spring 73 so that the magnetic core 82 and the rubber magnet 83 are attracted and locked when the exciting coil 81 is not energized. The energization coil 81 may be energized so that the lock is released when the camera operation is started. In this case, the power consumption is increased by using the mechanical lock mechanism as well, but even if the user drops the camera when transporting the camera or using the camera, the movable member around the image sensor 24 is prevented from being damaged. Can be achieved.

(Embodiment 2)
Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 14 is a horizontal sectional view showing a configuration example around the electromagnetic drive mechanism according to the second embodiment. The same parts as those shown in Embodiment Mode 1 are denoted by the same reference numerals.

  In the second embodiment, heat conducting portions 71a that come in contact with and separate from the support plate 31 (thermal conductive member 75) are formed to protrude at a plurality of locations on the surface side of the movable heat radiating plate 71. The electromagnetic drive mechanism 300 serving as an energization drive mechanism is arranged between the back side of the movable heat radiating plate 71 and the fixed heat radiating plate 58, and is configured to generate an electromagnetic driving force as a driving force when energized. ing. In FIG. 14, only one electromagnetic drive mechanism 300 is shown, but a plurality of, for example, six electromagnetic drive mechanisms 300 are provided as in the case of the electromagnetic drive mechanism 80 of the first embodiment. Such an electromagnetic drive mechanism 300 includes a drive coil 301, a magnetic core 302, and a permanent magnet 303. The magnetic core 302 is provided on a printed circuit board 304 provided on the surface side of the fixed heat radiating plate 58 by being fixed with an adhesive so that the axis is along the optical axis O, and a drive coil 301 is wound around the magnetic core 302. Has been. The permanent magnet 303 is composed of a neodymium magnet, and moves in the vicinity of the magnetic core 302 so that the direction of the magnetic flux is parallel to the surface of the movable heat radiating plate 71 (thus orthogonal to the optical axis O). It is arranged on the back side of the plate 71.

  In the vicinity of the permanent magnet 303, a hall element 305 is soldered on the printed circuit board 304 so as to face the movable heat radiating plate 71. The Hall element 305 is for detecting the position of the movable heat radiating plate 71 to detect the interruption (disconnection) of the drive coil 301.

  A compression coil spring 73 is provided on the guide shaft 72 to move the movable heat radiating plate 71 back, and is positioned between the movable heat radiating plate 71 and the fixed heat radiating plate 58 (printed circuit board 304). A separate compression coil spring 310 is provided for biasing the movable heat radiating plate 71 toward the support plate 31. Here, the elastic force of the compression coil spring 73 is set larger than the elastic force of the compression coil spring 310. Further, a heat conductive sheet 311 for conducting heat well is interposed between the movable heat radiating plate 71 and the fixed heat radiating plate 58. The thermally conductive sheet 311 is made of, for example, a graphite sheet or a silicon rubber sheet, and is configured to apply a pressure corresponding to the difference in elastic force between the compression coil springs 73 and 310 to the movable heat radiating plate 71.

  In such a configuration, when the temperature in the vicinity of the image sensor 24 is lower than the predetermined temperature and the drive coil 301 is not energized, the movable heat radiating plate 71 has a fixed heat dissipation according to the magnitude relationship of the elastic forces of the compression coil springs 73 and 310. It stops in a state of being biased toward the plate 58 side. In this state, the heat conducting portion 71a is not in contact with the support plate 31 (the heat conducting member 75) on the image pickup device 24 side.

  Then, when the temperature in the vicinity of the image pickup element 24 becomes equal to or higher than the predetermined temperature and a drive current in a predetermined direction is supplied to the drive coil 301, a downward force is applied to the permanent magnet 303, and thus the movable heat radiating plate 71 due to the electromagnetic drive action of the drive coil 301. Acts to move the movable heat radiating plate 71 toward the support plate 31 against the spring force of the compression coil spring 73. Thereby, the heat conduction part 71a of the movable heat sink 71 will be in a contact state with respect to the support plate 31 (heat conductive member 75). Therefore, the heat generated in the image sensor 24 is transferred to the movable heat radiating plate 71 through the support plate 31 (thermal conductive member 75) and the heat conductive portion 71a. The heat of the movable heat radiating plate 71 is transferred from the guide shaft 72 to the fixed heat radiating plate 58 side, and also to the fixed heat radiating plate 58 side through the heat conductive sheet 311 disposed around the electromagnetic drive mechanism 300. Heat is transferred. In this way, a heat dissipation path for the heat generated in the image sensor 24 is formed, and the temperature rise of the image sensor 24 is suppressed.

  Thereafter, when the temperature in the vicinity of the image sensor 24 decreases and the energization to the drive coil 301 is stopped, the downward force on the permanent magnet 303 does not work, and the movable heat radiating plate 71 returns to the original position by the elastic force of the compression coil spring 73. Then, the heat conducting portion 71a is separated from the support plate 31.

  According to the second embodiment, by winding the drive coil 301 around the magnetic core 302, the magnetic core 302 can be moved with low power and the power consumption can be suppressed. Heat generation can be suppressed. Further, since the heat conductive sheet 311 is always in contact when the movable heat sink 71 is moved up and down, the heat conductive sheet 311 is applied to the downward force acting on the permanent magnet 303 and the movable heat sink 71 by energizing the drive coil 301. The repulsive force 311 is also added, and the power consumption of the drive coil 301 can be reduced.

(Modification)
In addition, regarding the electromagnetic drive mechanism 300 of the second embodiment, the drive coil 301, the magnetic core 302, and the permanent magnet 303 may be disposed so as to be interchanged. That is, the drive coil 301 and the magnetic core 302 are provided on the movable heat radiating plate 71 side together with the printed circuit board 304, the permanent magnet 303 is provided on the fixed heat radiating plate 58 side, and the drive coil 301 and the magnetic core are energized. The 302 side may move. In accordance with this, in the configuration of the electromagnetic drive mechanism 80 shown in the first embodiment, the exciting coil 81 is provided as a drive coil, and the magnetic flux is brought close to the drive coil 81 on the support plate 31 (thermally conductive member 75). A permanent magnet whose magnetic flux direction is set so as to pass through the drive coil 81 is provided, and when the drive coil (excitation coil 81) is energized, the drive coil 81 and the magnetic core 80 move, and the movable heat sink 71 moves. It may be.

(Embodiment 3)
The third embodiment of the present invention will be described with reference to FIG. FIG. 15 is a horizontal sectional view showing a configuration example around the shape memory alloy spring according to the third embodiment. The same parts as those shown in the first and second embodiments are denoted by the same reference numerals.

  In the third embodiment, heat conducting portions 71b that come in contact with and separate from the support plate 31 (the heat conductive member 75) are embedded in a plurality of locations on the movable heat radiating plate 71 so as to protrude toward the support plate 31 side. In the third embodiment, instead of the compression coil spring 310 shown in FIG. 14, a shape memory alloy spring 320 serving as an energization drive mechanism is interposed between the movable heat sink 71 and the fixed heat sink 58 (printed circuit board 304). Positioned on the guide shaft 72. Here, when the shape memory alloy is cooled below the martensite transformation end temperature, it undergoes martensite transformation and changes from the austenite phase to the martensite phase. This causes a phase transformation that changes to the austenite phase. Such a shape memory alloy spring 320 is in a martensite phase state in a non-energized state, exhibits a spring force that balances with the elastic force of the compression coil spring 73, generates heat when energized, and transforms into an austenite phase. In this way, it changes in the extending direction and generates a spring force against the compression coil spring 73 as a driving force.

  Further, the base side of each heat conducting portion 71b is thermally connected and fixed to the fixed heat radiating plate 58 with a set screw 331 by a wire member 330 such as a ground wire. Further, between the fixed heat radiating plate 58 and the movable heat radiating plate 71, a heat conductive sheet 332 having a high heat conductivity such as a graphite sheet or a silicon rubber sheet is interposed. Therefore, the wire member 330 is provided so as to be laminated or embedded in the heat conductive sheet 332.

  In such a configuration, the elastic force of the compression coil spring 73 and the spring force of the shape memory alloy spring 320 are balanced when the temperature in the vicinity of the image sensor 24 is lower than a predetermined temperature and the shape memory alloy spring 320 is not energized. In this state, the heat conducting portion 71b is not in contact with the support plate 31 (the heat conducting member 75) on the image pickup device 24 side.

  When the temperature in the vicinity of the image sensor 24 becomes equal to or higher than the predetermined temperature and the shape memory alloy spring 320 is energized, the heat is generated and transformed into the austenite phase, so that it changes in the extending direction and resists the compression coil spring 73. Is generated as a driving force. At this time, since the shape memory alloy spring 320 is preheated by heat transfer through the path A via the guide shaft 72, the energization current to the shape memory alloy spring 320 may be small, and the power consumption can be reduced.

  Thereby, the movable heat radiating plate 71 moves to the support plate 31 side while being guided by the guide shaft 72, and the heat conducting portion 71b comes into contact with the support plate 31 (the heat conducting member 75). Therefore, the heat generated in the image sensor 24 is transferred to the movable heat radiating plate 71 via the support plate 31 (the heat conductive member 75) and the heat conductive portion 71b. The heat of the movable heat radiating plate 71 is favorably transferred to the fixed heat radiating plate 58 side through the path A via the guide shaft 72 and the path B via the heat conductive sheet 332. Further, the heat of the heat conducting portion 71 b is favorably transferred to the fixed heat radiating plate 58 side through the path C via the wire member 330. In this way, a heat dissipation path for the heat generated in the image sensor 24 is formed, and the temperature rise of the image sensor 24 is suppressed.

  After that, when the temperature in the vicinity of the image sensor 24 is decreased, the energization to the shape memory alloy spring 320 is stopped, and when the temperature of the shape memory alloy spring 320 is decreased, the shape memory alloy spring 320 is transformed into a martensite phase and is movable to a state balanced with the compression coil spring 73. The heat radiating plate 71 returns to the original position by the elastic force of the compression coil spring 73, and the heat conducting portion 71 b is separated from the support plate 31.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the embodiment, the first holding member 51 and the support plate 31 are arranged in a two-stage structure in which the first holding member 51 and the second holding member 52 are interposed between the fixing member 53 and the support plate 31. The member 51 can be displaced in the Y direction with respect to the second holding member 52 by the first driving mechanism 61, and the second holding member 52 is displaced in the X direction with respect to the fixed member 53 by the second driving mechanism 62. By making it possible, the displacement was moved in a two-dimensional direction orthogonal to the optical axis. However, the present invention is not limited to such a two-stage structure, but has a one-stage planar structure in which the support plate (first holding member) can be directly displaced in the XY direction with respect to the fixing member. It may be a drive mechanism that is displaced in the Y direction and the X direction directly with respect to the fixed member by the two drive mechanisms.

  The imaging device is not limited to a single-lens reflex digital camera with interchangeable lenses, but may be a compact digital camera, a mobile phone having a photographing function, a personal digital assistant, a notebook personal computer, an electronic medical device, or the like. However, the same can be applied.

  Furthermore, in this type of camera, there is a technique called a pixel shift method in which photographing is performed with a higher number of pixels than that of the CCD device. For example, this is a technique in which a normally taken image and two images taken by moving a movable part on which an image sensor is mounted obliquely by 1/2 pixel are continuously taken and the shutter speed is reduced to half. Therefore, not only when the image sensor 24 is displaced in the two-dimensional direction orthogonal to the optical axis O to prevent camera shake, but in this way, the image sensor is shifted in the two-dimensional direction orthogonal to the optical axis for pixel shifting. The present invention can also be applied to displacement movement.

1 is a central longitudinal front view showing an outline of an internal structure of a camera body of a single-lens reflex digital camera according to Embodiment 1 of the present invention. It is a vertical side view on the lens optical axis which shows the outline of an internal structure. It is a horizontal sectional view on the lens optical axis showing the outline of the internal structure. It is a perspective view which shows a heat conductive member. It is a horizontal sectional view in an optical axis part which extracts and shows a part of image pick-up unit at the time of de-energization and energization to an electromagnetic drive mechanism. It is a vertical side view in an optical axis part. It is a horizontal sectional view which shows in principle the further detailed structural example around a fixed heat sink and a movable heat sink. It is the modeled thermal circuit block diagram shown contrasting with a prior art example. FIG. 3 is a block diagram illustrating a configuration example of an electrical control system of the single-lens reflex digital camera according to the first embodiment. It is a graph which shows the correspondence of detection temperature T near an image sensor, and camera control operation. It is a schematic flowchart which shows the first half part of the operation control example of the camera performed by CPU. It is a schematic flowchart which shows the intermediate part of the example of operation control of the camera performed by CPU. It is a schematic flowchart which shows the second half part of the operation control example of the camera performed by CPU. It is a horizontal sectional view which extracts and shows the example of composition around the electromagnetic drive mechanism concerning Embodiment 2 of the present invention. It is a horizontal sectional view which extracts and shows the example of composition around the shape memory alloy spring concerning Embodiment 3 of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Single-lens reflex digital camera 10 Camera main body 11 Shooting lens 17 Liquid crystal monitor 24 Image pick-up element 25 Development unit 31 Support plate 53 Fixed member 58 Fixed heat sink 60 Drive mechanism 71 Movable heat sink 71a, 71b Heat conduction part 72 Guide shaft 80 Electromagnetic Drive mechanism 81 Excitation coil 82 Magnetic core 83 Rubber magnet 95 Wire member 96 Shield plate 99 Temperature sensor 101 CPU
300 Electromagnetic Drive Mechanism 301 Drive Coil 302 Magnetic Core 303 Permanent Magnet 320 Shape Memory Alloy Spring 332 Thermal Conductive Sheet

Claims (9)

An image sensor that is arranged on the optical axis of the photographic lens so as to be orthogonal to the optical axis and forms a subject image by the photographic lens;
A heat-radiating support plate on which the imaging element is mounted;
A fixing member having heat dissipation fixedly disposed at a position facing the back surface of the support plate;
A drive mechanism for displacing and moving the support plate on which the imaging element is mounted in a two-dimensional direction perpendicular to the optical axis with respect to the fixed member;
A temperature sensor for detecting a temperature in the vicinity of the image sensor;
A heat-dissipating part that contacts and separates from the support plate, and a movable heat radiating plate that is movably disposed on the support plate-facing surface side of the fixed member;
A guide member that has heat dissipation and is thermally coupled to the fixed member and the movable heat sink and guides the movement of the movable heat sink relative to the fixed member;
When the temperature in the vicinity of the image sensor detected by the temperature sensor is higher than a predetermined temperature, the movable heat sink is moved with respect to the fixed member so that the heat conducting portion comes into contact with the support plate when energized. An energization drive mechanism that generates a driving force to be
An elastic member that returns and moves the movable heat sink with respect to the fixed member so that the heat conducting portion is separated from the support plate when the energization drive mechanism is not energized;
The imaging unit according to claim 1, further comprising:   The imaging unit according to claim 1, wherein the energization driving mechanism is an electromagnetic driving mechanism that generates an electromagnetic driving force when the coil is energized.   The imaging unit according to claim 2, wherein the electromagnetic drive mechanism includes a combination of a magnetic core around which an excitation coil or a drive coil is wound and a permanent magnet. The magnetic core is disposed on the movable heat radiating plate along the optical axis and also serves as the heat conducting unit,
The permanent magnet is a rubber magnet or a rare earth magnet, and is disposed on the support plate so as to face the magnetic core.
The imaging unit according to claim 3, wherein an electromagnetic attractive force is generated between the magnetic core and the permanent magnet when the excitation coil is energized. The magnetic core is disposed on the fixing member with the axis along the optical axis,
The permanent magnet is composed of a neodymium magnet, and is disposed on the movable heat sink so that the magnetic flux direction is perpendicular to the optical axis and close to the magnetic core.
The imaging unit according to claim 3, wherein an electromagnetic driving force that relatively moves the magnetic core and the permanent magnet is generated by energizing the driving coil.   The imaging unit according to claim 1, wherein the energization drive mechanism is a shape memory alloy spring that generates a spring force as a drive force when energized. The shape memory alloy spring is disposed between the movable heat sink and the fixed member,
The imaging unit according to claim 6, further comprising a heat conductive sheet disposed between the movable heat sink and the fixed member.   The imaging unit according to claim 1, wherein the heat conducting unit is connected to a shield plate of a display device thermally coupled to the fixing member by a wire member that conducts heat. . The imaging unit according to any one of claims 1 to 8,
A camera body in which the photographing lens is mounted and the fixing member is fixedly arranged to incorporate the imaging unit;
Control means for controlling energization to the energization drive mechanism based on the temperature detected by the temperature sensor;
An imaging apparatus comprising:

Images