JP2010268133A - Imaging unit and electronic camera including the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently dissipates heat of an imaging device without complicating a heat dissipation structure interposed between an XY stage and a fixed stage. <P>SOLUTION: An imaging unit 15 includes a movable member 51 capable of being displaced in an optical axis direction of a taking lens, between a retaining plate 29 which is displaced together with an XY stage 33 and is thermally coupled with a CCD 23 disposed on the XY stage 33, and a fixed stage 31 having heat dissipating property. A heat absorber 52 is connected to the side nearer to the retaining plate 29 of the movable member 51, and a thermally conductive rubber sheet 54 is disposed between the fixed stage 31 and the movable member 51 so as to be always in contact with both the fixed stage 31 and the movable member 51. In the imaging unit 15, when a temperature detected by a temperature sensor for detecting an ambient temperature of a CCD 23 becomes higher than a first temperature, the movable member 51 is displaced by a driving means to press-fit the heat absorber 52 to the retaining plate 29. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an imaging unit having a heat dissipation mechanism and an electronic camera incorporating the imaging unit.

  In general, in an electronic camera, a light beam transmitted through a photographing lens is received by an image sensor such as a CCD, and image data is obtained based on the photoelectric conversion output. At that time, the dark current generated by the heat generation of the image sensor causes noise, and the image quality is degraded. Therefore, it is necessary to take measures against heat radiation of the image sensor. Therefore, various heat dissipation measures have been taken conventionally.

  On the other hand, in recent electronic cameras, an XY stage that is mounted with an image sensor and can be displaced in a two-dimensional direction (XY direction) orthogonal to the optical axis, an image blur correction drive mechanism that moves the XY stage in the XY direction, and an electronic camera In some cases, the image pickup device is displaced by an image blur correction drive mechanism so that the image blur is corrected when the image blur is detected. In this case, a heat radiating member for radiating heat from the image pickup device cannot be directly attached to the XY stage, and thus it is necessary to devise measures for heat radiation.

  Therefore, for example, in Patent Document 1, heat is transferred from the heat radiating member to the heat radiating member on the fixed stage side by placing the surfaces of the heat radiating member on the XY stage side and the fixed heat radiating member on the fixed stage side as close as possible to face each other. I am doing so. In Patent Document 2, heat is transferred from the XY stage side to the fixed stage side by interposing a magnetic fluid between the radiating plates facing the XY stage side and the fixed stage side.

JP 2006-174226 A JP 2006-31027 A

  However, the method according to Patent Document 1 dissipates heat generated on the XY stage side into the air inside the camera casing by convection, and further transfers heat to the components via the heat dissipating member inside the casing. It is designed to dissipate heat outside the body. In this method, 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 low and the heat dissipation efficiency is deteriorated.

  Further, the method according to Patent Document 2 requires that the magnetic fluid functioning as a heat transfer member be prevented from flowing out, and the structure becomes complicated. Furthermore, if a magnetic fluid is used, it will also become an expensive imaging unit.

  Therefore, an object of the present invention made by paying attention to these points is imaging capable of efficiently performing heat radiation of the imaging element without complicating a heat radiation structure interposed between the XY stage and the fixed stage. To provide a unit.

The invention of the imaging unit according to claim 1 that achieves the above object is as follows.
An XY stage displaceable in an XY direction orthogonal to the optical axis of the photographing lens;
An image sensor that is disposed on the XY stage and forms a subject image by the photographing lens;
A plate-like heat transfer member that is thermally coupled to the back surface of the image sensor and is displaced together with the image sensor in accordance with the displacement of the XY stage;
A heat-dissipating fixing member facing the back side of the imaging element of the plate-like heat transfer member,
A movable member provided between the plate-like heat transfer member and the fixed member so as to be displaceable in the optical axis direction of the photographing lens;
A heat absorber coupled to the plate-like heat transfer member side of the movable member;
A heat conducting means disposed between the fixed member and the movable member so as to always contact both the fixed member and the movable member;
A temperature sensor for detecting a temperature around the image sensor;
Driving means for generating a driving force for displacing the movable member with respect to the fixed member according to the temperature around the imaging element detected by the temperature sensor;
When the temperature detected by the temperature sensor becomes equal to or higher than the first temperature, the movable member is driven to the plate-like heat transfer member side by the driving means, and the heat absorber is moved to the plate-like heat transfer member. When the temperature detected by the temperature sensor becomes equal to or lower than the second temperature lower than the first temperature, the movable member is driven to the fixed member side by the driving means. The heat absorber is configured to be separated from the plate-shaped heat transfer member.

  According to a second aspect of the present invention, in the imaging unit according to the first aspect, a low-pass filter is disposed on the XY stage in front of a surface on which a subject image of the imaging element is formed. It is a feature.

  According to a third aspect of the present invention, in the imaging unit according to the first or second aspect, the drive means includes an electromagnetic drive mechanism including a coil on one of the fixed member and the movable member and a permanent magnet on the other. It is characterized by having.

  According to a fourth aspect of the present invention, in the imaging unit according to the first or second aspect, the driving means includes a shape memory alloy spring that generates a spring force as a driving force when energized. Is.

  According to a fifth aspect of the present invention, in the imaging unit according to the fourth aspect, the shape memory alloy spring stands between the movable member and the fixed member (here, standing on a fixed heat radiating plate shown in FIG. 10). The plurality of guide shafts 73 are wound around the outer periphery of the guide shaft 73.

  An invention of an electronic camera according to a sixth aspect that achieves the above object is characterized by comprising the imaging unit according to any one of the first to fifth aspects.

  According to the present invention, the driving means for generating a driving force for displacing the movable member with respect to the fixed member according to the temperature of the imaging element detected by the temperature sensor is provided, and the temperature detected by the temperature sensor is the first. When the temperature is equal to or higher than the temperature, the driving member drives the movable member toward the plate-like heat transfer member to press the heat absorber against the plate-like heat transfer member, and the temperature detected by the temperature sensor is the second temperature. When the temperature is lower than the temperature, the movable member is driven to the fixed member side by the driving means so that the heat absorber is separated from the plate-like heat transfer member, so that it is interposed between the XY stage and the fixed member. The heat dissipation of the image sensor can be efficiently performed without complicating the heat dissipation structure.

It is a cross-sectional view along the photographic lens optical axis of the electronic camera provided with the imaging unit according to the first embodiment of the present invention. It is AA sectional drawing of FIG. It is a disassembled perspective view of the imaging unit integrated in the camera of FIG. FIG. 4 is a partial cross-sectional view along the X direction through the optical axis O of the image pickup unit of FIG. 3, showing a state where the clamp pin of the center clamp mechanism is retracted (open state). FIG. 4 is a cross-sectional view of a portion close to a guide shaft 34b of the imaging unit in FIG. It is a figure explaining camera control by temperature of CCD at the time of live view operation. It is a fragmentary sectional view of the image pick-up unit concerning a 2nd embodiment of the present invention. FIG. 8 is an enlarged view around the Hall element and the flat coil of FIG. 7. It is the top view which looked at the image pick-up unit of Drawing 7 from the image sensor side. It is a fragmentary sectional view of the image pick-up unit concerning a 3rd embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a cross-sectional view taken along an optical axis of a photographing lens of a single-lens reflex digital camera (hereinafter referred to as a camera) that is an image pickup apparatus including an image pickup unit according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the line AA in FIG.

  The camera 10 according to the present embodiment includes a camera body 1 and a lens unit 2 that is interchangeably mounted on the front side of the camera body 1 and includes a photographing lens 21.

  The camera body 1 has a resin exterior cover 3 for housing camera constituent members, and a lens unit 2 including the photographic lens 21 is interchangeably loaded at a front side position on the optical axis O of the photographic lens 21. A ring-shaped mount portion 4 is provided. The exterior cover 3 is provided with a grip portion 3a that is held by the right hand of the operator at the time of shooting or the like on the left side as viewed from the front side. Various switches such as a release button and buttons are arranged on the top of the grip portion 3a.

  As shown in FIGS. 1 and 2, the camera body 1 further includes a liquid crystal panel 6 having an acrylic panel display window 5 at a position on the optical axis O on the back side of the exterior cover 3. The liquid crystal panel 6 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. Further, the exterior cover 3 is provided with a finder window 7 through which an operator peeks at the time of shooting, and a hot shoe 8 for attaching an external flash is disposed on the top.

  Further, as shown in FIG. 1, the camera body 1 incorporates a mirror member such as a quick return mirror 9 disposed on the optical axis O on the front side in the exterior cover 3, and detects a defocus amount below the mirror member. A mirror box 12 containing the AF sensor unit 11 and the like is provided. Further, a focal plane shutter 13 and an imaging unit 15 including an imaging element and the like are sequentially arranged on the back side of the quick return mirror 9 of the mirror box 12 so as to be orthogonal to the optical axis O. Further, a sub mirror 9 a is disposed behind the quick return mirror 9, and an optical path is set so as to guide reflected light from the sub mirror 9 a to the AF sensor unit 11. On the other hand, on the reflection side optical axis of the quick return mirror 9, a roof mirror 16, an eyepiece 17 and the like are arranged.

  Further, the camera body 1 includes a battery storage chamber 19 for storing the battery 18 inside the grip portion 3 a of the exterior cover 3. Further, inside the grip portion 3a, on the back side of the battery storage chamber 19, a circuit for performing control of the entire camera, image processing, compression processing, data storage processing, etc., a memory such as SDRAM, a power supply circuit, etc. are mounted. A circuit board (not shown) is provided.

  Next, the imaging unit 15 will be described in detail with reference to FIGS. FIG. 3 is an exploded perspective view of the imaging unit 15. 4 is a partial cross-sectional view showing a cross section of a half on one side along the X direction of FIG. 3 through the optical axis O of the photographing lens 21, and a state in which the clamp pin of the center clamp mechanism is retracted (released state) Indicates. FIG. 5 is a cross-sectional view of a portion close to the guide shaft 34 in the other half on the other side along the X direction passing through the optical axis O of the imaging unit in FIG. 3.

  In the following description, the direction parallel to the optical axis O of the photographing lens is defined as the Z direction, the subject side in the Z direction is defined as the front, and the image side is defined as the rear (back side). Further, the right and left direction in FIG. 2 orthogonal to each other on a plane with the Z direction as a normal line is defined as the X direction, and the vertical direction is defined as the Y direction.

  First, the image blur correction mechanism of the imaging unit 15 will be described. The image blur correction mechanism detects camera shake at the time of imaging, and corrects the image blur by displacing the CCD 23 (package or bare chip) that is an image sensor. For this reason, the camera 10 has a shake detection unit (not shown). Further, the imaging unit 15 detects the position in the Y direction and the position in the X direction of the XY stage 33 that supports the CCD 23, for example, by an X position sensor and a Y position sensor configured by Hall elements 39a and 39b, respectively. Based on the detected blur and information on the X position and the Y position, a control mechanism (not shown) of the camera 10 controls the movement of the CCD 23 so as to cancel the image blur on the imaging surface of the CCD 23 due to the blur of the camera 10.

  As shown in FIG. 3, the imaging unit 15 includes a fixed stage 31 fixedly supported inside the camera body 1, a Y stage 32 that can move relative to the fixed stage 31 in the Y direction, and an optical LPF (low-pass filter). ) 22 and the CCD 23 are mounted, and can be moved relative to the Y stage 32 in the X direction. In other words, the XY stage 33 can be moved relative to the fixed stage 31 on the XY plane. .

  The fixed stage 31 includes a frame body 31a having an opening in the central region in the direction of the optical axis O, and a flat base member 31b provided behind the frame body 31a. The base member 31 b has a screw hole for fixing in the camera body 1. Further, the base member 31b has a protruding portion that is rectangular when viewed in the Z direction rearward at the center. A bottom portion 31c that forms the bottom surface of the rectangular protruding portion is a plane orthogonal to the optical axis O.

  In the frame 31a, a pair of guide shafts 34a and 34b extending in the Y direction are arranged in parallel with a gap therebetween with the optical axis O interposed therebetween. Further, four rectangular parallelepiped permanent magnets 35a, 35b, 35c, and 35d are arranged as drive magnets on the inner side of the frame 31a. The four permanent magnets 35a to 35d form a pair of two permanent magnets. The pair of permanent magnets 35a and 35b is disposed outside the pair of guide shafts 34a and 34b in parallel with the guide shafts 34a and 34b. Further, the other pair of permanent magnets 35c and 35d are opposed to each other with an interval in the Y direction across the optical axis of the photographing lens 21 in the XY plane.

  The base member 31b is made of a soft magnetic metal, is fixed to the frame body 31a, and is fixed to the Z-direction rear end surfaces of the permanent magnets 35a to 35d. Further, a center clamp mechanism 41 (to be described later) and a heat dissipation mechanism 50 integrated with the center clamp mechanism 41 are disposed on the bottom 31c of the base member 31b.

  The Y stage 32 is a rectangular frame having an opening that penetrates the optical axis O direction in the central region, and a pair of guide shafts 36a and 36b extending in the X direction are spaced in the Y direction with the optical axis O in between. Is provided. Further, the Y stage 32 is formed with projecting pieces having two sets of bearing-shaped guide shaft holes 32a, 32a ′ and 32b, 32b ′ facing each other at an interval in the Y direction on both sides in the X direction of the Y stage. Yes. The guide shaft 34a of the fixed stage 31 is slidably fitted into the guide shaft holes 32a and 32a ′, and the guide shaft 34b of the fixed stage 31 is slidably fitted into the guide shaft holes 32b and 32b ′. Yes. As a result, the Y stage 32 can move in the Y direction.

  The XY stage 33 is a rectangular frame having a pair of coil mounting plate portions 33a and 33b projecting in the Y direction and a pair of coil mounting plate portions 33c and 33d projecting in the X direction. Further, the optical LPF 22 and the CCD 23 are fixed at the center of the XY stage 33 so as to be orthogonal to the optical axis O in order from the front in the Z direction.

  The optical LPF 22 is supported on the front surface of the central opening of the XY stage 33 via a rubber member 27 (see FIG. 4).

  The CCD 23 is supported on the rear side of the central opening of the XY stage 33 in a state of being mounted on the CCD printed circuit board 25, and a protective glass 24 is mounted on the entire surface. A flexible printed board 26 for connection is connected to the printed board 25.

  Further, a pair of bearing-shaped guide shaft holes facing each other with a gap in the X direction are formed on the back side of the coil mounting plates 33a and 33b of the XY stage 33, and the Y stage 32 is formed in the guide shaft holes. A pair of guide shafts 36a and 36b are fitted and supported so as to be slidable in the X direction. The XY stage 33 is held by the fixed stage 31 and the Y stage 32 so as to be movable along the XY plane, and functions as a guide stage that moves on a plane orthogonal to the optical axis O.

  Coil bodies 37 and 37 ', which are flat and spiral electromagnetic driving means, are connected in series and attached to the pair of coil mounting plate portions 33a and 33b, respectively. Further, coil bodies 38 and 38 ', which are flat and spiral electromagnetic driving means, are attached to the pair of coil mounting plate portions 33c and 33d, respectively. The coil bodies 38 and 38 'are also connected in series.

  Each coil body 37, 37 'is disposed adjacent to the front of the permanent magnets 35c, 35d, respectively. The coil bodies 38 and 38 'are arranged adjacent to the front in the Z direction of the permanent magnets 35a and 35b, respectively. The pair of coil bodies 37, 37 'is used to drive the XY stage 33 in the Y direction, and the pair of coil bodies 38, 38' is used to drive the XY stage 33 in the X direction.

  A Hall element is used as the position detection element of the XY stage 33. Specifically, a hall element 39a as a position detecting element is arranged on one coil attachment plate portion 33b of the pair of coil attachment plate portions 33a and 33b. Similarly, one coil attachment plate of the pair of coil attachment plate portions 33c and 33d. A hall element 39b is disposed in the portion 33d.

  FIG. 4 shows a state in which the fixed stage 31, the Y stage 32, and the XY stage 33 are properly arranged in order from the bottom. The permanent magnet 35 a is fixed to the frame body 31 a and the base member 31 b of the fixed stage 31, and the end surface opposite to the base member 31 b (that is, the front in the Z direction) faces the coil body 38. The bottom 31c of the fixed stage 31 is provided with a through hole 31d for preventing the permanent magnet 33g and the magnetic material 33j from interfering with the bottom 31c while the XY stage 33 is held at the center position. .

  The center clamp mechanism 41 provided in the imaging unit 15 is a center clamp mechanism for holding the XY stage 33 at the center position when the coil bodies 37, 37 ′, 38, and 38 ′ that are image blur correction coils are not energized. . As shown in FIG. 4, the center clamp mechanism is disposed between the bottom 31c of the fixed stage 31 and the XY stage 33, and includes a clamp pin 42, a clamp coil 46, and an urging force provided on the fixed stage side. The spring 45 includes an engagement hole 33h, a permanent magnet 33g, and a magnetic material 33j provided on the XY stage side.

  The clamp pin 42 is a pressing member made of a magnetic material, and is slidably passed through and supported by the bottom portion 31 c of the fixed stage 31. The distal end portion of the clamp pin 42 is tapered, and a retaining ring is formed immediately after the distal end portion. The clamp coil 46 is wound around the clamp pin 42 so as to come into contact with the retaining ring at the tip of the clamp pin and the bottom 31c of the fixed stage 31. The urging spring 45 is inserted into a portion where the clamp pin 42 protrudes rearward from the pin hole of the bottom portion 31c, and the rear end portion of the urging spring 45 contacts the E-type retaining ring 43 provided at the rear end of the clamp pin 42. It touches.

  The engagement hole 33h is formed as a tapered hole provided at a position where the XY stage 33 is engaged with the clamp pin 42 when the XY stage 33 is at the center position, that is, the position where the center of the CCD 23 coincides with the optical axis O. Yes. One end of the permanent magnet 33g and the magnetic material 33j is fixed to the front XY stage 33, and the other end extends toward the through hole 31d of the bottom 31c. The permanent magnet 33g is magnetized in the thickness direction (X direction). Further, the magnetic material 33j is for preventing leakage of magnetic flux to the back side of the permanent magnet 33g, and is disposed in contact with the back side of the permanent magnet 33g when viewed from the clamping coil 46.

  In the center clamp mechanism 41, when no current flows through the clamp coil 46, the clamp pin 42 is moved rearward by the biasing force of the biasing spring 45 as shown in FIG. The part is in a state where it has escaped from the engagement hole 33h of the XY stage 33, that is, in a state where the XY stage 33 can move on the XY plane (release state).

  When the XY stage 33 is at the center position, when a current is passed through the clamp coil 46, the clamp pin 42 is fixed to the clamp pin 42 and is movable later, due to electromagnetic force generated between the permanent magnet 33g and the magnetic field. It moves forward together with the member 51, and the tapered tip end portion 42 a is fitted into the engagement hole 33 h of the XY stage 33 to be in an engaged state. In this engaged state, the XY stage 33 is clamped at the center position. Next, when the current flowing through the clamping coil 46 is stopped while the XY stage 33 is clamped at the center position, the electromagnetic force acting on the clamping coil 46 disappears, and the urging spring 45 causes the clamp pin 42 to move. It is displaced rearward together with the movable member 51. Therefore, in the present embodiment, the drive means is configured as an electromagnetic drive mechanism including the permanent magnet 33g, the clamp pin 42, the clamp coil 46, and the biasing spring 45.

  On the other hand, as shown in FIG. 5, a permanent magnet 33 f is provided on the bottom of the frame body on the coil mounting plate portion 33 d side of the XY stage 33. The permanent magnet 33f removes play between the guide shaft hole of the XY stage 33 and the guide shafts 36a and 36b, and further removes play of the guide shafts 34a and 34b with respect to the guide shaft holes 32a and 32a ′ and 32b and 32b ′. Provided to do.

  Next, a heat dissipation mechanism 50 for generating heat generated by the CCD 23 will be described with reference to FIG. First, in the XY stage 33, the insulating sheet 28, the printed board 25, and the FPC board 26 connected to the printed board 25 are sequentially arranged on the back side of the CCD 23, and further, a plate-like heat transfer member arranged on the back side. It is supported by a presser plate 29 made of an aluminum thin plate having high thermal conductivity. Thereby, the heat generated in the CCD 23 is efficiently transferred to the holding plate 29. The presser plate 29 and the bottom 31c of the fixed stage 31 that is a fixing member are substantially parallel to each other.

  The movable member 51 is fitted between the clamp pin 42 and two other clamp pins (not shown), supported by them, and disposed between the bottom 31 c of the fixed stage 31 and the presser plate 29. The movable member 51 can be displaced in the direction of the optical axis of the photographic lens 21 between the bottom 31 c and the presser plate 29 in accordance with the displacement of the clamp pin 41. The material of the movable member 51 is, for example, black PPS resin filled with spherical graphite or carbon.

  The movable member 51 has a recess around the optical axis of the photographic lens 22, and a heat absorber 52 is fixed to the recess via a metal base 53 having an adhesive on both sides. The heat absorber 52 is a sheet having high heat conductivity, for example, composed of a porous material based on black synthetic resin (PPS resin or PC resin) in which pores are filled with aluminum powder, silicon gel, or carbon fiber. is there. This sheet is produced by applying a porous metal plating (evaporation) to the surface of a PPS resin or the like. Alternatively, graphite is disposed on the surface of the heat absorber 52 that contacts the presser plate 29, and a porous material is laminated between the graphite and the metal base 53. By doing so, it is possible to prevent the generation of sound due to the contact between the presser plate 29 and the heat absorber 52, and to increase the contact area with the presser plate having poor flatness, thereby increasing the heat conduction efficiency. Can do.

  The heat absorber 52 may use a silicon columnar or silicon gel liquid instead of the porous structure.

  Further, between the bottom 31c of the fixed stage 31 and the movable member 51, a heat conductive rubber sheet 54 made of silicon or graphite having elastic force, which is a heat conductive means, is interposed. As the sheet 54, a sheet thickness is selected such that a compressive force is always applied to the thermally conductive rubber sheet 54 between the bottom 31c and the movable member 51. That is, even when the distal end portion of the clamp pin 42 is engaged with the engagement hole 33h and the movable member 51 is displaced most forward, the heat conductive rubber sheet 54, the bottom portion 31c of the fixed stage 31, and the movable member Contact with 51 is maintained.

  Further, for example, a temperature sensor (not shown) is embedded between the heat conductive rubber sheet 54 and the bottom 31 c of the fixed stage 31 or between the heat absorber 52 and the metal base 53 in the movable member 51. The temperature around the CCD 23 is detected. The temperature detected by the temperature sensor is transmitted to a CPU in a system controller (not shown) of the camera 10.

  Further, in the portion where the movable member 51 outside the thermally conductive rubber sheet 54 and the bottom portion 31c of the fixed stage 31 face each other, the movable member 51 and the bottom portion 31c are respectively provided with a reflective sheet 56, a light emitting element and a light receiving element. A photo reflector 55 integrated with the element is provided to face the element. The reflection sheet 56 and the photo reflector 55 are provided to measure the displacement of the movable member 51 in the Z direction with respect to the fixed stage 31.

  Next, a heat dissipation path for radiating heat generated in the CCD 23 of the camera 10 of the present embodiment to the outside of the camera 10 will be described.

  On the back side of the fixed stage 31, a shield plate (not shown), the liquid crystal panel 6, and an acrylic panel display window 5 are arranged, and the fixed stage 31 is in a heat transfer relationship therewith.

  A part of the heat on the back side of the CCD 23 serving as a heat source is radiated through the air layer, the optical LPF 22, and the air layer, but many other parts are transferred to the presser plate 29 made of aluminum. At this time, when the heat absorber 52 is in contact with the presser plate 29, the heat of the presser plate 29 is efficiently transmitted to the movable member 51 via the heat absorber 52, and further, the heat is transferred from the movable member 51. It is transmitted to the bottom 31 c of the fixed stage 31 through the conductive rubber sheet 54. The heat transmitted to the fixed stage 31 is efficiently transmitted to the shield plate via a heat conductive sheet or the like (not shown), and is directly radiated to the outside or transmitted to the liquid crystal panel 6 side. The heat is radiated to the outside through the panel display window 5 made of metal. Therefore, in a state where the heat absorber 52 is in contact with the presser plate 29, the imaging unit 15 can dissipate heat more efficiently than the conventional example. On the other hand, when the heat absorber 52 is not in contact with the presser plate 29, the heat of the presser plate 29 is not efficiently transmitted to the heat absorber 52, and the heat dissipation efficiency is lowered.

  Next, the operation of the imaging unit 15 according to the present embodiment will be described. The imaging unit 15 is controlled by a CPU in a system controller (not shown) of the camera 10 based on the temperature detected by the temperature sensor.

  FIG. 6 is a diagram for explaining the control of the camera 10 based on the temperature detected by the temperature sensor during the live view operation. In FIG. 6, T1 to T4 are determination values of the temperature on the back side of the CCD 23, which is a determination reference when the CPU controls the imaging unit, T3 is the first temperature, and T1 is the second temperature. is there. These determination values have a magnitude relationship of T1 <T2 <T3 <T4. These determination values T1 to T4 are recorded in a flash ROM (not shown) as control parameters. Note that the temperature on the back side of the CCD 23 is derived from the detected temperature in consideration of the temperature difference between the temperature on the back side of the CCD 23 and the detected temperature of the temperature sensor.

  In the following, it is assumed that the camera 10 is turned on from a state where the detected temperature is sufficiently low, the camera operation starts, and the user selects, for example, a live view operation. In this state, no current flows through the clamp coil 46 of the clamp mechanism 41, and the E-type retaining ring 43 of the clamp pin 42 is pushed backward by the biasing spring 45. As a result, the movable member 51 fitted to the clamp pin 42 is located rearward, and the heat absorber 52 is separated from the presser plate 29.

  After the start of the live view operation, in the state where the temperature T on the back side of the CCD 23 is lower than the determination value T2, the display rate of the liquid crystal monitor (that is, the image reading rate from the CCD 23) is set to 30 fps. When the CCD 23 continuously operates, the temperature T on the back side of the CCD 23 rises, and when T exceeds the determination value T2 at time t1, the display rate of the liquid crystal monitor is changed from 30 fps to 15 fps under the control of the CPU. By lowering the display rate, the temperature rise of the CCD 23 is suppressed.

  However, in some cases, such as when the outside temperature of the camera is high, the temperature rise of the image sensor cannot be sufficiently suppressed. In this case, for example, if the temperature T exceeds the determination value T3 at time t2, in order to efficiently release the heat of the image pickup device while the display rate of the liquid crystal monitor is lowered, a clamp actuator driving circuit (not shown) Thus, the clamp coil 46 is energized, the movable member 51 is raised, and the presser plate 29 is pressure-bonded so that the heat absorbing body 52 composed of the porous member is in a contracted state. By this crimping operation, the heat generated on the back surface of the CCD 23 is transferred to the movable member 51 having the metal base 53 through the heat absorbing body 52 of a porous material that can be expanded and contracted, and the heat of the movable member 51 is also thermally conductive. Heat is transferred to the bottom 31c of the fixed stage 31 through a heat conductive rubber sheet 54 composed of a high silicon rubber sheet or graphite sheet, and is radiated from the shield plate, the liquid crystal panel 6 and the acrylic panel display window 5.

  Normally, the temperature rise of the CCD 23 is stopped by the two temperature rise prevention operations, that is, the display rate changing operation and the heat dissipation operation via the heat absorber 52, and the temperature gradually decreases. Therefore, as shown in FIG. 6, at time t3, when the temperature T falls below the determination value T1, the display rate of the liquid crystal monitor is changed from 15 fps to 30 fps by the control of the CPU, and the clamping coil 46 is not turned on. Energization is performed and the crimping operation is released, and the two temperature rise prevention operations are stopped. It should be noted that the temperature rise prevention operation is not stopped until the temperature rises below the judgment value T2 when the temperature rise prevention operation is started and stopped based on the judgment value T2. This is because the operation becomes unstable when in the vicinity, and a dead zone is ensured.

  On the other hand, if the temperature rise does not stop and the determination value T4 is exceeded at time t4 despite the above two temperature rise prevention operations, the system of the camera 10 is forcibly stopped.

  In the above description, it is assumed that the temperature of the CCD 23 increases with the live view operation. However, even when the user does not select the live view operation, for example, the state in which the user presses the release switch in the continuous shooting mode. When the image capturing operation is continuously executed as in the case of maintaining the image quality, the temperature of the image sensor can similarly rise. Even in such a case, the above-described two temperature rise prevention operations are executed.

  As described above, according to the present embodiment, the driving means for displacing the movable member 51 according to the temperature of the CCD 23 detected by the temperature sensor is provided, so that the space between the XY stage 33 and the fixed stage 31 is provided. When the detected temperature exceeds T3 without complicating the heat dissipation structure interposed in the heat sink, the heat absorber 52 is pressure-bonded to the holding plate 29, and the heat generated by the CCD 23 is transferred to the movable member 51 and the heat conductive rubber. Heat can be efficiently radiated to the outside of the camera via the sheet 54 and the fixed stage 31. When the detected temperature is lower than T1, the heat absorber 52 can be separated from the presser plate 29 to release the heat dissipation operation.

(Second Embodiment)
FIG. 7 is a partial cross-sectional view including a cross-sectional view along the X direction passing through the optical axis of the imaging unit 15 according to the second embodiment of the present invention. In the present embodiment, a driving unit having a different configuration is used instead of the driving unit of the movable member 51 of the imaging unit 15 according to the first embodiment. That is, in the present embodiment, instead of the drive means including the permanent magnet 33g, the clamp pin 42, the clamp coil 46, and the biasing spring 45 used in the first embodiment, the fixed stage 31 is fixed to the bottom 31c. The coil indicating plate 63 extending forward in the Z direction along the Z axis, the flat coil 65 fixed to the coil support plate, and the second magnet 66 fixed to the movable member 51 are used as driving means.

  The coil support plate 63 is a member having an L-shaped cross section when viewed in the Y direction, and one end of the L shape is fixed to the bottom 31c of the fixed stage 31 with a screw, bent at a right angle, and provided in the bottom 31c. It passes through the portion 31e and extends forward in the Z direction to the opening 51a of the movable member 51. As shown in FIG. 8, a hall element 64 and an oblong (rectangular) flat coil 65 are joined around the hall element 64 to a flat plate portion extending in the Z direction of the coil support plate 63. Is facing.

  FIG. 8A is a view of the coil support plate 63 as viewed in the X direction (from left to right in FIG. 7). FIG. 8B is a view of the coil support plate 63 viewed in the Y direction (front view in FIG. 7). The second magnet 66 is obtained by connecting two flat rectangular permanent magnets in the front-rear direction (up and down in FIG. 8). The front magnet has an N pole, and the rear magnet has an S pole facing the flat coil. ing. The Hall element detects the position of the movable member 51 by detecting the vertical position of the boundary between the magnetic poles of the second magnet 66.

  FIG. 9 is a plan view of the imaging unit 15 viewed from the front (object side) CCD 23 side. The movable member 51 is positioned by the three positioning pins 68a, 68b, 68c that are fitted. Further, the XY stage 33 is provided with one circular positioning hole at a position where the positioning pin 68a engages and two ellipses whose major axis directions are the X direction and the Y direction at positions where the positioning pins 68b and 68c are engaged. A positioning hole having a shape is provided. The positioning pins 68a to 68c are different from the clamp pin 42 of the first embodiment in that the positioning pins 68a to 68c are biased rearward by leaf springs 61a to 61c fixed by set screws 62a to 62c as shown in FIG. ing. The heat conductive rubber sheets 54a and 54b are rectangular sheets having long sides in the two Y directions with the coil support plate 63 interposed therebetween.

  Since other configurations are the same as those of the first embodiment, the same components are denoted by the same reference numerals, and description thereof is omitted. Also in the electronic camera of the present embodiment, camera control based on the temperature of the CCD 23 is performed as described with reference to FIG.

  With the configuration as described above, according to the present embodiment, the movable member 51 for crimping the heat absorber 52 to the presser plate 29 when the temperature T described in the first embodiment exceeds the determination value T3. Can be driven by energizing the flat coil 65 with a clamp actuator drive circuit (not shown). Further, the heat-absorbing body 52 can be released from the press-bonded state by stopping the energization of the flat coil 65. Other operations are the same as those in the first embodiment.

  As described above, according to the present embodiment, there are the same effects as those of the first embodiment, and furthermore, since the driving means is provided around the optical axis in the imaging unit 15, a set of coils. The movable member 51 can be driven by a combination of a magnet and a magnet, and a simpler and less expensive device configuration than the imaging unit according to the first embodiment can be obtained.

(Third embodiment)
FIG. 10 is a partial cross-sectional view along the X direction passing through the optical axis of the imaging unit 15 according to the third embodiment of the present invention. This embodiment is different from the first embodiment in the configuration of the fixed stage.

  In FIG. 10, the Y stage, the XY stage, and the Y stage guide mechanism and drive mechanism are omitted. In the XY stage 33, a protective glass 24 is provided on the front surface of the CCD 23, and a flexible printed circuit board 26 and a pressing plate 29 such as an aluminum thin plate are provided on the rear surface side. The optical LPF 22 included in the first embodiment is omitted in FIG. On the other hand, as the fixed stage, a fixed heat radiating plate 77 which is a fixed member fixed to the camera body is provided. On the fixed heat radiating plate 77, a movable heat radiating plate 71 which is a movable member, a heat absorber 72, and a heat A heat conductive sheet 76 that is a conduction means, wire members 78 and 81, a micro bellows 79, and a drive means for driving the movable heat radiation plate 71 with respect to the fixed heat radiation plate 77 are arranged.

  Here, the driving means includes a guide shaft 73, a compression coil spring 74, and a shape memory alloy spring 75. The guide shafts 73 are cylindrical guide shafts 73 extending forward in the Z direction from three locations of the fixed heat dissipation plate 77, and each guide shaft 73 slidably penetrates the movable heat dissipation plate 71 which is a movable member, This movable heat sink 71 is held at three locations. The shape memory alloy spring 75 is between the fixed heat sink 77 and the movable heat sink 71, and the compression coil spring 74 is between the retaining ring provided at the upper end of the guide shaft 73 and the movable heat sink 71. Are wound around the guide shaft 73.

  Here, when the shape memory alloy used for the shape memory alloy spring 75 is cooled below the martensite transformation end temperature, the martensite transformation occurs and changes from the austenite phase to the martensite phase, but the reverse transformation end temperature is exceeded by energization. When heated to a temperature, a phase transformation that changes from the martensite phase to the austenite phase occurs. Such a shape memory alloy spring 75 is in a martensite phase in a non-energized state, exhibits a spring force that balances with the elastic force of the compression coil spring 74, generates heat when energized, and transforms into an austenite phase. As a result, a spring force that resists the compression coil spring 73 is generated as a driving force.

  The movable heat radiating plate 71 is a member that can be displaced in the Z direction by sliding with the three guide shafts 73 as described above, and a concave portion is formed in front of the movable heat radiating plate 71 around the optical axis of the photographing lens 21. The heat absorber 72 is fixed to the recess so as to fit the rear (lower side in FIG. 10) portion. In addition, heat radiating fins 71 a are embedded outside the recesses so as to protrude toward the presser plate 29.

  The heat conductive sheet 76 is a sheet-like member having high heat conductivity, such as a graphite sheet or a silicon rubber sheet, provided between the fixed heat radiating plate 77 and the movable heat radiating plate 71. A compressive force is always applied to the heat conductive sheet 76 between the movable heat radiating plate 71 and the fixed heat radiating plate 77, and even when the movable heat radiating plate 71 is displaced forward most, the heat conductive sheet 76. And the contact with both the movable heat sink 71 and the fixed heat sink 77 is maintained.

  Further, the fixed heat radiating plate 77 side of the heat absorber 72 is connected to one end of a micro bellows 79 provided in a hollow portion in the heat conductive sheet 76 by a wire member 78 such as a lead wire penetrating the movable heat radiating plate 71. Is done. Further, the other end of the micro bellows 79 is connected to one end of a wire member 81 disposed between the heat conductive sheet 76 and the fixed heat radiating plate 77. The other end of the wire member 81 is thermally connected to the fixed heat radiating plate 77 with a set screw 82. The end of the micro bellows 79 on the side of the fixed heat radiating plate 71 is fixed with an adhesive. The micro bellows 79 expands and contracts in accordance with the displacement of the movable heat radiating plate 71, and the heat absorber 72 and the fixed heat radiating plate 77 via the wire member 78. Maintain thermal contact between. As a material of the micro bellows 79, a metal such as phosphor bronze or a synthetic resin material such as PC (polycarbonate) having high thermal conductivity can be used.

  In order to connect the wire member 78 and the wire member 81, a compressible coil spring or a leaf spring may be provided in place of the micro bellows 79.

  In addition, the fixed heat radiating member 77 is provided with a preliminary heat radiating portion 83 for radiating heat from other heat sources in the camera 10 to the fixed heat radiating plate 77. For example, an image blur correction apparatus disclosed in Japanese Patent Application Laid-Open No. 2008-48220 includes a motor and a drive unit that drive a Y stage and an XY stage in the Y axis and X axis directions, respectively. Such heat generated by the motor can be radiated to the fixed heat radiating plate 77.

  Since other configurations are the same as those of the first embodiment, the same components are denoted by the same reference numerals, and description thereof is omitted. Also in the electronic camera of the present embodiment, camera control based on the temperature of the CCD is performed as described with reference to FIG.

  With the above configuration, according to the present embodiment, the elastic force of the compression coil spring 74 is obtained when the temperature of the CCD 23 is lower than the determination value T3 that is the first temperature and the shape memory alloy spring 75 is not energized. And the spring force of the shape memory alloy spring 75 are balanced, and in this state, the heat absorber 72 is not in contact with the presser plate 29 that holds the FPC board on the back side of the CCD 23.

  On the other hand, when the temperature of the CCD 23 becomes equal to or higher than the determination value T3, the shape memory alloy spring 75 is energized to generate heat and transformed into the austenite phase, so that the shape memory alloy spring 75 changes in the extending direction and resists the compression coil spring 74. Is generated as a driving force. At this time, since the shape memory alloy spring 75 is preheated by the heat transfer of the path A via the guide shaft 73, the energization current to the shape memory alloy spring 75 may be small, and the power consumption can be reduced. .

  Due to the driving force generated by the shape memory alloy spring 75, the movable heat radiating plate 71 moves toward the holding plate 29 holding the FPC board 26 while being guided by the guide shaft 73, and the heat absorber 72 is crimped to the holding plate 29. It will be in a contracted state. Therefore, the heat generated in the CCD 23 is transferred to the movable heat radiating plate 71 through the pressing plate 29 and the heat absorber 72. Part of this heat is radiated into the air by the heat radiating fins 71a. The heat of the movable heat radiating plate 71 is favorably transferred to the fixed heat radiating plate 77 side through the path A via the guide shaft 73 and the path B via the heat conductive sheet 76. Further, the heat of the heat absorber 72 is also favorably transferred to the fixed heat radiating plate 77 side by the path C through the wire member 78. In this way, a heat dissipation path for the heat generated in the CCD 23 is formed, and the temperature rise of the CCD 23 is suppressed.

  Thereafter, when the temperature in the vicinity of the CCD 23 falls below the determination value T1, which is the second temperature, the energization to the shape memory alloy spring 75 is stopped under the control of the CPU (not shown). As a result, when the temperature of the shape memory alloy spring 75 decreases, the shape memory alloy spring 75 is transformed into a martensite phase, and the movable heat radiating plate 71 returns to the original position that balances with the elastic force of the compression coil spring 74 to absorb heat. The body 72 is separated from the presser plate 29.

  As described above, according to the present embodiment, since the shape memory alloy spring 75 is used as the driving means, the movable heat radiating plate 71 can be displaced by energizing the shape memory spring 75. The same effect as in the first embodiment can be obtained. Furthermore, in the present embodiment, by providing a heat radiation path using the heat radiation fins 71a and the wire member 78, the heat of the heat absorber 72 can be radiated more efficiently.

  In addition, this invention is not limited only to the said embodiment, Many deformation | transformation or a change is possible. For example, the imaging device is not limited to a single-lens reflex digital camera with interchangeable lenses, but may be, for example, a compact digital camera, a mobile phone having a photographing function, a portable information terminal, a notebook personal computer, an electronic medical device, or the like. However, the same can be applied.

  Moreover, although CCD was used as an image pick-up element, you may use other image pick-up elements, such as CMOS. Furthermore, although the display element is an LCD, other display elements such as an organic EL may be used.

  Further, the heat conduction means is not limited to a metal wire such as silicon, graphite sheet, and ground wire, but may be replaced with a heat pipe having a wick formed on the inner wall or a plurality of compression coil springs.

  Furthermore, in the driving means in the first and second embodiments described above, a clamping coil or a flat coil is disposed on the fixed member side, and a permanent magnet is disposed on the movable member side. The driving means may be configured by disposing a permanent magnet on the fixed member side and providing a coil on the movable member side.

  In addition, 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. This technique is, for example, a technique in which a normal photographed image and two images photographed by obliquely displacing a movable part on which an image sensor is mounted by ½ pixel are continuously photographed and the shutter speed is halved. It is. The present invention is not limited to the case where the image sensor 24 is displaced and moved in the two-dimensional direction orthogonal to the optical axis in order to prevent camera shake. As described above, the image sensor is shifted in the two-dimensional direction orthogonal to the optical axis for pixel shifting. It can also be applied to the case of displacement.

DESCRIPTION OF SYMBOLS 1 Camera body 2 Lens unit 3 Exterior cover 3a Grip part 4 Mount part 5 Panel display window 6 Liquid crystal panel 7 Finder window 8 Hot shoe 9 Quick return mirror 9a Sub mirror 10 Camera 11 AF sensor unit 12 Mirror box 13 Focal plane shutter 15 Imaging unit 16 Dach mirror 17 Eyepiece 18 Battery 19 Battery storage chamber 21 Shooting lens 22 Optical low pass filter (optical LPF)
23 CCD
24 Protective Glass 25 Printed Circuit Board 26 Flexible Printed Circuit Board 27 Rubber Member 28 Insulating Sheet 29 Press Plate (Plate Heat Transfer Member)
31 Fixed stage (fixed member)
31a Frame 31b Base member 31c Bottom 31d Through hole 31e Opening 32 Y stage 32a, 32a ′ Guide shaft hole 33 XY stage 33a-33d Coil mounting plate 33e, 33f Permanent magnet 33g, 33i Permanent magnet 33h Engagement hole 33j Magnetic Materials 34a, 34b Guide shafts 35a-35d Permanent magnets 36a, 36b Guide shafts 37, 37 'Coil bodies 38, 38' Coil bodies 39a, 39b Hall element 41 Center clamp mechanism 42 Clamp pin (pressing member)
43 E-type retaining ring 44 E-type retaining ring 45 Biasing spring (elastic member)
46 Clamping Coil 50 Heat Dissipation Mechanism 51 Movable Member 51a Opening Portion 52 Heat Absorber 53 Metal Bases 54, 54a, 54b Thermal Conductive Sheet (Heat Conducting Means)
55 Photo reflector 56 Reflective sheet 57 Magnetic materials 61a and 61b Leaf spring 62 Set screw 63 Coil support plate 64 Hall element 65 Flat coil 66 Second magnet 67 Adhesive materials 68a to 68c Positioning pin 71 Movable heat dissipation plate (movable member)
71a Radiation fin 72 Heat absorber 73 Guide shaft 74 Compression coil spring 75 Shape memory alloy spring 76 Thermal conductive sheet (thermal conduction means)
77 Fixed heat sink (fixing member)
78 Wire member 79 Micro bellows 81 Wire member 82 Set screw 83 Preliminary heat conduction part

Claims (6)

An XY stage displaceable in an XY direction orthogonal to the optical axis of the photographing lens;
An image sensor that is disposed on the XY stage and forms a subject image by the photographing lens;
A plate-like heat transfer member that is thermally coupled to the back surface of the image sensor and is displaced together with the image sensor in accordance with the displacement of the XY stage;
A heat-dissipating fixing member facing the back side of the imaging element of the plate-like heat transfer member,
A movable member provided between the plate-like heat transfer member and the fixed member so as to be displaceable in the optical axis direction of the photographing lens;
A heat absorber coupled to the plate-like heat transfer member side of the movable member;
A heat conducting means disposed between the fixed member and the movable member so as to always contact both the fixed member and the movable member;
A temperature sensor for detecting a temperature around the image sensor;
Driving means for generating a driving force for displacing the movable member with respect to the fixed member according to the temperature around the imaging element detected by the temperature sensor;
When the temperature detected by the temperature sensor becomes equal to or higher than the first temperature, the movable member is driven to the plate-like heat transfer member side by the driving means, and the heat absorber is moved to the plate-like heat transfer member. When the temperature detected by the temperature sensor becomes equal to or lower than the second temperature lower than the first temperature, the movable member is driven to the fixed member side by the driving means. An image pickup unit configured to separate a heat absorber from the plate-like heat transfer member.   The imaging unit according to claim 1, wherein a low-pass filter is disposed on the XY stage in front of a surface on which a subject image of the imaging element is formed.   The imaging unit according to claim 1, wherein the driving unit includes an electromagnetic driving mechanism including a coil on one of the fixed member and the movable member and a permanent magnet on the other.   The imaging unit according to claim 1, wherein the driving unit includes a shape memory alloy spring that generates a spring force as a driving force when energized.   The imaging unit according to claim 4, wherein the shape memory alloy spring is disposed between the movable member and the fixed member.   The electronic camera provided with the imaging unit as described in any one of Claims 1-5.

Images