JP4963563B2 - Foreign matter removing device and imaging device - Google Patents

Description

  The present invention relates to a technique for removing foreign substances adhering to the surface of an image sensor incorporated in an electronic camera or the like or the surface of an optical element arranged in front of the image sensor.

  A so-called electronic camera that captures still images and moving images using an imaging optical system and an image sensor such as a CCD or C-MOS sensor is a zoom optical system, a focusing optical system, a shutter, an iris (iris), a quick return mirror, and the like. Generally, it has a movable mechanism. Here, wear dust discharged from the sliding part in the movable mechanism, foreign matter such as dust entering from the outside world, an optical low-pass filter disposed in the vicinity of the image sensor cover glass or the image sensor, or infrared cut May adhere to the surface of the filter. If shooting is performed with the dust attached, a shadow of the dust is imprinted together with the subject image, and a high-quality image may not be obtained.

  Therefore, various mechanisms for cleaning the surface of the optical element using a wiper-like member have been proposed as one method for removing the dust.

  For example, Japanese Patent Laid-Open No. 2001-298640 (Patent Document 1) or Japanese Patent Laid-Open No. 2003-18440 (Patent Document 2) discloses the following technique. That is, the wiper supported by the motor shaft wipes and scans the glass surface of the image pickup element built in the digital single-lens reflex camera, and removes dust adhering to the surface.

  Japanese Patent Application Laid-Open No. 2004-172961 (Patent Document 3) discloses that a belt-shaped cleaning film is driven in the left-right direction by a take-up roller, and the take-up roller moves in the up-down direction. A mechanism for cleaning is disclosed.

Japanese Patent Laid-Open No. 2005-5972 (Patent Document 4) discloses that a wiper member supported at both ends by a ribbon (belt) cleans the surface of an image sensor in conjunction with an operation of mounting an interchangeable lens on a camera body. A mechanism is disclosed.
JP 2001-298640 A JP 2003-18440 A JP 2004-172961 A JP 2005-5972 A

  However, the above known techniques have the following drawbacks.

  In the devices disclosed in Patent Literature 1 and Patent Literature 2, since one end of the wiper is supported by the motor shaft and the other end is a free end, the wiper pressing force distribution on the glass surface can be made uniform. It is difficult and the dust removal effect may vary depending on the location. Further, since the rotational torque necessary for driving the wiper is proportional to the entire length of the wiper, there is a problem that an excessive load is applied to the wiper motor when cleaning a large area optical element.

  In the apparatus disclosed in Patent Document 3, it is difficult to make the pressure distribution of the cleaning film uniform with respect to the surface of the image sensor, and the pressure becomes minimum at the center of the image sensor. Further, when the pressing force between the cleaning film and the image sensor is set to an appropriate value, the tension of the film must be several times greater than the pressing force. Therefore, in this apparatus, there is a risk of film breakage, and there is a problem that a large output is required for the drive source for the take-up roller due to a load on the take-up roller due to film tension.

  Similarly, in the apparatus disclosed in Patent Document 4, in order to set the pressing force between the wiper member and the image sensor to an appropriate value, it is necessary to apply a large tension to the ribbon that conveys the wiper member. Therefore, in this apparatus, there is a risk that the ribbon may be broken, and the driving load of the take-up drum increases due to the ribbon tension, and the load required for mounting the lens also increases.

  Therefore, the present invention has been made in view of the above-described problems, and the object thereof is to clean the entire surface of the optical effective range of the optical element substantially uniformly when removing the foreign matter on the surface of the optical element for cleaning. Is to do so.

In order to solve the above-described problems and achieve the object, a foreign matter removing apparatus according to the present invention is a foreign matter removing device for removing foreign matter adhering to a surface to be cleaned which is a surface of an optical element. A lead screw arranged outside the element, a drive source for driving the lead screw, a nut screwed to the lead screw, and pivotally supported with respect to the nut and attached to the surface to be cleaned A foreign matter removing member for removing the foreign matter, and when the drive source drives the lead screw in the first direction, the nut is caused to rotate by a frictional force between the lead screw and the nut. The force which presses the said foreign material removal member substantially uniformly against the said to-be-cleaned surface acts, It is characterized by the above-mentioned.

According to the present invention, when removing the foreign matter on the surface of the optical element for cleaning , the foreign matter removing member can be pressed almost uniformly against the surface of the optical element with a simple configuration for cleaning.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings.

(First embodiment)
1 to 4 are diagrams for explaining a first embodiment of the present invention.

  FIG. 1 is a cross-sectional view showing a configuration of a camera which is a first embodiment of an imaging apparatus of the present invention, and shows a shooting preparation state of a digital single-lens reflex camera system including a camera body and an interchangeable lens.

  In FIG. 1, reference numeral 1 denotes a camera body. An interchangeable lens 80 that can be attached to and detached from the camera body 1 is fixed by a camera mount 2 and a lens mount 82. The camera-side contact 3 and the lens-side contact 84 come into contact with each other, so that an in-camera control circuit (not shown) and an in-lens control circuit are electrically connected. Communication for controlling the lens is performed.

  The light beam that has passed through the photographing optical system 81 of the interchangeable lens 80 is incident on the main mirror 5 of the camera. The main mirror 5 is a half mirror, and the light beam reflected here is guided to the finder screen 9, and a subject image is formed on the finder screen 9. The photographer can observe the subject image on the finder screen 9 through the penta roof prism 11 and the eyepiece 12.

  On the other hand, the light beam transmitted through the main mirror 5 is reflected downward by the sub mirror 7 and guided to the focus detection device 10. The focus detection device 10 detects a focus shift amount of the photographic optical system 81, a so-called defocus amount, and calculates a lens driving amount for driving the photographic optical system 81 so that the photographic optical system 81 is in focus. When this lens driving amount is sent to the interchangeable lens 80 via the contact portions 3 and 84, the lens controls a motor (not shown) and drives the photographing optical system 81 to adjust the focus.

  The main mirror 5 is bonded and fixed to the main mirror holding frame 6, and is rotatably supported with respect to the mirror box 100 by a hinge shaft 6a. Further, the sub mirror 7 is bonded and fixed to the sub mirror holding frame 8, and the sub mirror holding frame 8 is pivotally supported by the hinge shaft 8a so as to be rotatable with respect to the main mirror holding frame 6.

  A focal plane shutter 13 is disposed behind the sub-mirror 7, and the shutter front curtain 13a is normally closed, that is, a state where a later-described image sensor is shielded. An optical filter 14 in which an optical low-pass filter and an infrared cut filter are integrated is disposed behind the shutter 13, and a light beam that has passed through the optical filter 14 is incident on an image sensor 15 disposed further rearward during photographing.

  The image sensor 15 includes a cover glass 15a, a sensor package 15b, a sensor chip 15c, and a sensor substrate 15d. Here, the image pickup device or the image pickup means refers to a sensor chip 15c alone in a narrow sense, an image pickup device unit composed of the above 15a to 15d in a broad sense, and a structure in which the image pickup device unit and the optical filter 14 are combined. To do.

  Reference numeral 60 denotes a display such as an LCD, which displays information related to the shooting mode of the camera, a preview image before shooting and a confirmation image after shooting, information related to the progress of the dust removal process, and the like.

  A cleaning unit 20 for removing dust adhering to the surface of the optical filter 14 is arranged behind the shutter 13 and outside the optically effective surface of the optical filter 14. Reference numeral 31 denotes a wiper which will be described later, and constitutes one part constituting the cleaning unit 20. The LED 4 is an illuminating device for illuminating the optical filter 14 and the image sensor 15 from the lower surface side of the mirror box 100 in order to detect the operation status of the cleaning unit 20 and to detect dust adhering to the optical filter 14. A white LED is used.

  2A and 2B are diagrams showing the structure of the cleaning unit 20. FIG. 2A is a perspective view of the cleaning unit alone viewed from the photographic lens side, FIG. 2B is a cross-sectional view thereof, and FIG. A perspective view when assembled in the vicinity, FIG.

  In FIG. 2A, reference numeral 21 denotes a frame corresponding to the housing of the cleaning unit 20, which is composed of rectangular plate-like members 21a, 21b, 21c and 21d surrounding the optical filter 14 to be cleaned. Each member is held.

  First, holes 21a1, 21a2, 21b1, 21b2 are perforated at both ends of the upper frame 21a and the lower frame 21b, and lead screws 22 and 23 are rotatably mounted. Here, the lead screw 22 is formed with a right-hand thread, and the lead screw 23 is formed with a left-hand thread. A motor base 21m is formed at the outer lower end of the side frame 21c, and the motor 24 is fixed. Further, holes 21c1 and 21d1 are formed at the lower ends of the side frames 21c and 21d, and the motor shaft 25 is rotatably held. The bevel gears 26a and 26b are fixed to both ends of the motor shaft 25, the bevel gears 26c and 26d are fixed to the lower ends of the lead screws 22 and 23, the bevel gears 26a and 26c are engaged, and the bevel gears 26b and 26d are engaged. They are engaged.

  Reference numeral 31 denotes a wiper, which is a belt-like member composed of a metal base 31a and a flocked portion 31b. Here, the metal pedestal 31a is made of a metal plate that can be regarded as a substantially rigid body, and fibers having a length of about 0.3 mm are densely planted on the back surface thereof, that is, the surface facing the optical filter 14, by electrostatic flocking. . Instead of the electrostatic flocking treatment, other members having a dust removing ability such as a velvet-like cloth or a non-woven fabric may be attached using an adhesive tape. Reference numerals 27 and 28 denote nuts for supporting and driving the wiper 31, and are screwed into the lead screws 22 and 23. Reference numerals 29 and 30 denote leaf springs, which are provided to generate a predetermined pressing force between the wiper 31 and the optical filter 14. One end is fixed to the end of the wiper 31 and the other end is fixed to the tip of the nuts 27 and 28. Established.

  Further, wiper position detection devices 32 and 33 are provided at the upper and lower ends of the side frame 21c. The wiper position detection devices 32 and 33 are preferably photoelectric sensors such as photo reflectors, and the wiper position detection device 32 detects the light beam emitted from the light projecting unit and reflected by the nut 27 as the subject by the light receiving unit. , 33 is detected whether or not the nut 27 is present.

  In the above configuration, when the motor 24 is energized and the motor shaft 25 is rotated in the direction of the arrow in FIG. 2A, the rotation of the lead screws 22 and 23 is opposite to each other via the four bevel gears 26a to 29d. Rotate in the same direction and at the same rotation speed. Then, since the rotation causes the nuts 27 and 28 to be driven from the top to the bottom at the same speed, the wiper 31 moves in parallel from the top to the bottom, that is, moves straight.

  FIG. 2C is a diagram illustrating a state in which the cleaning unit 20 is incorporated in front of the image sensor 15 and the optical filter 14. In this state, the flocked portion 31b on the back surface of the wiper 31 is in contact with the front surface of the optical filter 14, and an equal pressing force is applied to both ends of the wiper 31 according to the amount of elastic deformation of the leaf springs 29 and 30. Since the pedestal 31a of the wiper 31 is highly rigid and does not elastically deform, the flocked portion 31b abuts uniformly on the front surface of the optical filter 14, and the pressure distribution between the flocked and the filter surface becomes uniform. Therefore, when the wiper 31 is scanned while being in contact with the surface of the optical filter 14, foreign matters such as dust attached to the surface of the optical filter 14 are reliably removed. When the wiper 31 reaches the lower end, the wiper position detection device 33 detects this, reverses the motor 24, and the wiper 31 moves backward. When the wiper 31 returns to the initial position, that is, the upper end, the wiper position detection device 32 detects this, stops the motor 24, and completes one reciprocating dust removal operation.

  Next, the arrangement of the cleaning unit 20 in the optical axis direction in the camera will be described.

  As shown in FIG. 2 (d), a wiper 31, which is a minimum member necessary for dust removal, and a leaf spring 29 supporting the wiper 31 are provided in front of the light incident surface of the optical filter 14 (left side in the figure). 30 and only the tips of the nuts 27 and 28 are arranged. Other main parts, that is, main parts such as a frame body 21 corresponding to a casing, a motor 24 corresponding to a drive unit, lead screws 22 and 23, nuts 27 and 28, and the like are arranged as follows. That is, the optical filter 14 is arranged behind the light incident surface (the direction not protruding from the surface) and in the outer space of the optical filter 14 and the sensor package 15b of the image sensor. With the above configuration, a reduction in shutter efficiency is prevented by keeping the distance between the shutter 13 and the sensor chip 15c to the minimum necessary. Further, by arranging the wiper drive mechanism in the outer peripheral space of the optical filter 14 and the sensor package 15b having a relatively large space, it is easy to ensure the rigidity of the constituent members and the fitting length of the sliding portion, and the reliability. A high cleaning unit can be provided.

  In this embodiment, the leaf springs 29 and 30 are used as members for generating a contact force between the wiper 31 and the optical filter 14, but other elastic members such as a tension coil spring, a compression coil spring, a torsion coil spring, and a rubber bush are used. Etc. may be used.

  Moreover, although the embodiment using a bevel gear is shown as means for equalizing the drive speeds of the two lead screws, a mechanism in which a worm is mounted on the motor shaft and a worm wheel is mounted on the lead screw may be used.

  FIG. 3 is a block diagram showing the electrical circuit configuration of the camera of this embodiment. First, various circuits built in the camera body 1 will be described with reference to FIGS.

  Reference numeral 41 denotes an in-camera CPU which controls various controls of the camera body 1 and includes a calculation unit, ROM, RAM, A / D converter, D / A converter, communication interface circuit, and the like. Reference numeral 42 denotes an in-camera power supply circuit, which includes a secondary battery such as a lithium ion battery and a booster circuit. A photometric sensor driving circuit 43 drives the photometric sensor 16 shown in FIG. 1, calculates a photometric result, and sends the output to the in-camera CPU 41. Reference numeral 44 denotes a display driver circuit, which controls display of the display 60. An operation switch drive circuit 45 determines whether various operation switches (not shown) such as a power switch, a release (shooting trigger) switch, a shooting mode selection switch, and the like have been operated. Reference numeral 46 denotes a detachable flash memory for recording a photographed image. A cleaning mechanism drive circuit 47 controls the driving of the cleaning unit 20 described with reference to FIG.

  An LED drive circuit 54 controls the lighting of the LED 4. Reference numeral 55 denotes an image sensor driving circuit that controls the imaging operation of the image sensor 15 and transmits the acquired image signal to the in-camera CPU 41. Reference numeral 50 denotes an AF sensor drive circuit that drives an AF sensor built in the focus detection apparatus 10 and transmits a focus detection signal to the in-camera CPU 41. A mirror driving circuit 52 drives the main mirror holding frame 6 to move the main mirror 5 and the sub mirror 7 in and out of the photographing optical path. Reference numeral 53 denotes a shutter drive circuit that performs drive trigger control of the front curtain and rear curtain of the shutter 13 based on a command signal from the in-camera CPU 41, and drives a charge motor (not shown) after completion of exposure control to Charge the running spring.

  Next, a circuit included in the interchangeable lens 80 will be described.

  Reference numeral 91 denotes an in-lens CPU, which includes a calculation unit, ROM, RAM, A / D converter, D / A converter, communication interface circuit, etc., and communicates with the in-camera CPU 41 to exchange various data and command signals. Control the circuit.

  An in-lens power circuit 92 supplies the power supplied from the in-camera power circuit 42 to various circuits and actuators in the lens. A diaphragm driving circuit 93 controls the aperture diameter of the iris diaphragm 83. A focus drive circuit 94 drives a focus motor (not shown) to drive the focus adjustment lens back and forth in the optical axis direction.

  Then, the camera side contact 3 and the lens side contact 84 are electrically connected in a state where the camera body 1 and the interchangeable lens 80 are coupled by the mount.

  FIG. 4 is a flowchart for explaining the dust removing process according to the present embodiment. In FIG. 4, the control flow is shown in the left column, the image acquired by the image sensor 15 is shown in the center column, and the image content displayed by the display device 60 is shown in the right column. The acquired image acquired by the image sensor 15 and the display image displayed on the display 60 are connected to the corresponding control step by a broken line. The control flow of FIG. 4 will be described below with reference to FIGS.

  When the photographer operates the operation switch (not shown) and selects the dust removal mode while viewing the display device 60 installed on the back surface of the camera body 1, a dust removal routine is started from step S101, and the display device 60 displays the dust removal routine. A screen is displayed asking whether to check the dust level. The display content at this time is shown in DSP-11.

  In step S103, if the photographer denies the execution of the dust level confirmation, the process proceeds to step S155 to end the dust removal routine. On the other hand, when the dust level confirmation is performed in step S103, the process proceeds from step S103 to step S111.

  In step S111, the main mirror 5 and the sub mirror 7 are retracted out of the photographing light beam, the diaphragm 83 is narrowed down to the minimum aperture diameter, and the front curtain of the focal plane shutter is driven to open the shutter.

  In step S113, the LED 4 is turned on, and the illumination light of the LED 4 passes through the optical filter 14 and the protective glass 15a of the image sensor 15 to illuminate the sensor chip 15c. FIG. 5 shows a cross-sectional view of the camera in this state. The aperture of the aperture 83 is minimized by the aperture operation, and the entry of external light into the mirror box is substantially blocked. Further, since the light source area of the LED 4 is very small, if dust adheres to the surface of the optical filter 14, a shadow of dust caused by the LED illumination light is projected onto the sensor chip 15c.

  In step S115, image storage and readout of the image sensor 15 are performed to obtain an image indicated by IMG-12. This image shows a state where black spots of various shapes corresponding to the shadows of dust attached to the surface of the optical filter 14 are scattered in the bright region illuminated substantially uniformly by the LEDs.

  In step S117, the dust region is extracted from the image acquired in step S115, and then the display image is emphasized. Specifically, a reference image (referred to as IMG-11 (not shown)) that is acquired when the camera body 1 is manufactured, that is, without dust adhering and stored in the ROM, is read out. And the dust adhering after manufacture is extracted by calculating the difference of the image IMG-11 for reference and the image IMG-12 acquired at step S115. Next, a dust level (a value representing the amount of dust, for example, the number of dust portions) is calculated. Since the technique etc. which were disclosed by Unexamined-Japanese-Patent No. 2003-23563 already filed by the applicant of this application can be utilized for the concrete method, detailed description is abbreviate | omitted. Thereafter, in the extracted dust image, enlargement of the dust portion and contrast enhancement are performed.

  In step S119, the enlarged dust image is further blinked and displayed on the display 60, thereby notifying the photographer of the dust adhesion state (DSP-12).

  In step S121, the dust level calculated in step S117 is displayed on the display device 60 (DSP-13). In the present embodiment, both the dust level recognized last time and the dust level recognized this time are quantitatively displayed as a bar graph and a numerical value. A selection button for determining whether or not to perform cleaning is also displayed at the bottom of the display screen. That is, the photographer compares the dust level of the previous time with that of the current time, and instructs whether or not to execute the cleaning process with the selection button.

  If it is selected in step S123 that no cleaning operation is required (No), the process proceeds to step S155, and the dust removal routine is terminated. On the other hand, if execution of the cleaning process (Yes) is selected in step S123, the process proceeds to step S131.

  In step S131, driving of the wiper 31 provided in the cleaning unit 20 is started. In step S133, a moving image during wiper driving is acquired (IMG-13). In step S135, the acquired moving image is sequentially displayed on the display device 60 (DSP-14). In this case, since the shadow of the wiper 31 moves on the screen, the photographer can easily see the progress of the cleaning process, and can also grasp the process of removing dust by the passage of the wiper 31. When the subject is photographed using the interchangeable lens 80, an inverted image is formed on the image sensor 15. Therefore, when displaying a normal subject image on the display 60, the top and bottom of the image is corrected and displayed. is doing. On the other hand, in the present embodiment, since the wiper 27 starts scanning from the upper side in the camera, the display 60 displays an image that is not upside down. As a result, the photographer can correctly recognize that the wiper is driven from the top to the bottom.

  In step S137, after determining that the forward scanning of the wiper 31 is completed, the wiper 31 is moved backward in the initial position, that is, upward in FIG.

  In step S139, a dust image is acquired by the same method as in step S115 (IMG-14), and in step S141, dust recognition and dust enhancement processing are performed by the same method as in step S117. In step S143, the dust adhesion status after the cleaning process is displayed by the same method as in step S119 (DSP-15). This screen allows the photographer to determine how much dust remains in which area.

  In step S145, the dust level recognized in step S141 is displayed on the display device 60 in the same manner as in step S121 (DSP-16). In the present embodiment, the dust levels before and after cleaning are quantitatively displayed as bar graphs and numerical values. At this time, when the dust level after cleaning is a predetermined value or more, it is effective to give a warning such as blinking the bar graph or displaying it in a conspicuous color. In addition, a selection button for determining whether or not to perform cleaning again is displayed at the bottom of the display screen. That is, the photographer can compare the dust levels before and after cleaning, quantitatively grasp the cleaning effect, and use the selection button to instruct whether or not to re-execute the cleaning process. The dust removal effect and warning information can be used as a judgment material when the photographer himself wipes and cleans the front surface of the optical element using a commercially available cleaning tool (such as a cotton swab, a cleaning cloth, or a blower brush).

  If execution of re-cleaning is selected in step S147, the process returns to step S131, and steps S131 to S151 are repeatedly executed. On the other hand, if it is selected in step S147 that re-cleaning is unnecessary, the process proceeds to step S151.

  In step S151, the LED 4 is turned off. In step S153, the rear curtain of the shutter is first moved to close the shutter, the aperture is returned to the open position, and the main mirror and sub mirror are returned to the photographing light flux. Next, the shutter curtain running spring is charged, and the shutter front curtain and the rear curtain are returned to a running state. In step S155, the dust removal routine is completed.

According to the above first embodiment, the following effects can be obtained.
(1) Since both ends of the belt-shaped wiper are supported by nuts and the two nuts are driven at a constant speed by lead screws, respectively, the surface of the optical filter can be reliably scanned with a small driving force.
(2) The main mechanism for driving the wiper is disposed on the imaging element side (the side not protruding from the surface) of the optical filter surface and at a position facing the optical filter with the optical axis interposed therebetween. Therefore, a shutter mechanism or another optical element can be disposed immediately before the optical filter, which is effective for downsizing the apparatus.
(3) Since both ends of the rigid wiper base are pressed against the optical filter by using an elastic member such as a leaf spring, the pressure distribution between the flocked portion on the wiper and the optical filter can be made uniform, and uniform over the entire optical filter. A good dust removal effect.

(Second Embodiment)
In the first embodiment, an example in which a uniform wiper distribution is obtained by pressing a wiper whose base is a rigid body against an optical filter with a leaf spring. In the second embodiment described below, an example of obtaining a uniform pressure distribution by using a wiper base as a leaf spring (elastic body) and curving its initial shape against a planar optical filter. Indicates. The configuration other than the wiper portion is the same as that of the first embodiment. Hereinafter, the configuration and operation of the second embodiment will be described with reference to FIGS. 5 and 6.

  FIG. 5 is a configuration diagram of the cleaning unit in the second embodiment, and corresponds to FIG. 2 in the first embodiment. In the cleaning unit 20 of the first embodiment, the wiper 31 is a belt-shaped rigid body that has been subjected to electrostatic flocking. On the other hand, in the cleaning unit 200 of the second embodiment, the wiper 231 is a band-like shape that is curved in advance so as to protrude toward the optical filter 14 with a predetermined curvature, as shown in FIG. Electrostatic flocking 231b is applied to the convex side of the leaf spring 231a. When the cleaning unit 200 is assembled on the surface side of the optical filter 14, the leaf spring-like wiper 231 is pressed against the front surface of the optical filter 14 as shown in FIG. 5C, and a substantially uniform pressing force is generated. The relationship between the initial shape of the leaf spring and the pressing force distribution at this time will be described with reference to FIG.

  FIG. 6A shows a state in which both ends of a linear beam are supported by fulcrums, and FIG. 6B shows that the beam is deflected when an equally distributed load w (unit: N / m) is applied to the beam. It shows a state of stagnation. This bending shape can be derived from the bending curve formula described in the literature of material mechanics. FIG. 6C is a diagram showing the shape of the wiper according to the second embodiment in an unloaded state.

  The wiper 231 is plastically deformed so as to have the same shape as the beam bending curve of FIG. 6B when manufacturing the strip-shaped leaf spring 231a, and then the electrostatic flocking 231b is formed on the surface that contacts the optical filter 14. Then, both ends are fixed to the tips of the nuts 27 and 28. FIG. 6D shows a state in which this is incorporated in the vicinity of the optical filter 14. When the contact amount between the wiper 231 and the optical filter 14 is gradually increased, the pressing force of the contact portion gradually increases, and the wiper 231 approaches a straight line according to the plane of the optical filter. When the shape reaches a straight line, the pressing force distribution coincides with the equally distributed load w shown in FIG. Therefore, the pressing force between the wiper 231 and the optical filter 14 is kept uniform by determining the relative position of the cleaning unit 200 and the optical filter 14 in advance so that the state shown in FIG. be able to.

According to the second embodiment described above, the following effects (3), (4), and (5) are obtained in addition to the following effects (1) and (2) similar to those of the first embodiment. It is done.
(1) Since both ends of the belt-shaped wiper are supported by nuts and the two nuts are driven at a constant speed by lead screws, respectively, the surface of the optical filter can be reliably scanned with a small driving force.
(2) Since the main mechanism for driving the wiper is disposed on the image sensor side of the optical filter surface and at a position facing the optical axis of the optical filter, the shutter mechanism or other optical element is provided immediately before the optical filter. This is effective for downsizing the apparatus.
(3) Since both ends of the leaf spring wiper base curved in a predetermined shape are supported and pressed against the optical filter, the pressure distribution between the flocked portion on the wiper and the optical filter can be made substantially uniform, and the entire area of the optical filter can be distributed. And uniform dust removal effect.
(4) Since the wiper and the pressing force generating member can be integrated, the device can be manufactured at low cost.
(5) Since the wiper can be thinned, the apparatus can be further reduced in size.

(Third embodiment)
In 1st and 2nd embodiment, the example which removes the dust of an optical filter with the flocking type wiper was shown. In the third embodiment described below, an example is shown in which a rubber blade type wiper is pressed against the surface of an optical filter and scanned to remove dust. The configuration other than the wiper portion is the same as that of the first embodiment. Hereinafter, the configuration and operation of the third embodiment will be described with reference to FIG.

  FIG. 7 is a configuration diagram of the cleaning unit in the third embodiment, and corresponds to FIG. 2 of the first embodiment. In the cleaning unit 20 of the first embodiment, the wiper 31 applies electrostatic flocking to a band-shaped rigid body, and supports this with nuts 27 and 28 via leaf springs 29 and 30. In contrast, in the cleaning unit 300 of the third embodiment, the wiper 331 is a rubber blade type wiper similar to a window wiper of an automobile. FIG. 7B shows an enlarged cross-sectional view of the cleaning unit alone. The wiper 331 includes a highly rigid metal frame 331a having a U-shaped cross section and a rubber blade 331b. As shown in FIG. 7A, both ends of the wiper 331 are coupled to nuts 27 and 28 via leaf springs 29 and 30, as in the first embodiment.

  Therefore, when the image pickup device 15 including the optical filter 14 is incorporated, the wiper 331 comes into contact with the optical filter 14 with a predetermined force by elastic deformation of the leaf springs 29 and 30 as shown in FIG. Then, as shown in FIG. 7D, the tip of the rubber blade 331b is deformed, and dust on the surface of the optical filter is removed by scanning the wiper 331 from top to bottom.

According to the third embodiment described above, effects (3) and (4) can be obtained in addition to the following effects (1) and (2) similar to those of the first embodiment.
(1) Since both ends of the belt-shaped wiper are supported by nuts and the two nuts are driven at a constant speed by lead screws, respectively, the surface of the optical filter can be reliably scanned with a small driving force.
(2) Since the main mechanism for driving the wiper is disposed on the image sensor side of the optical filter surface and at a position facing the optical axis of the optical filter, the shutter mechanism or other optical element is provided immediately before the optical filter. This is effective for downsizing the apparatus.
(3) Since both ends of the rigid wiper base are pressed against the optical filter using leaf springs, the pressure distribution between the tip of the rubber blade of the wiper and the optical filter can be made uniform, and dust can be removed uniformly throughout the optical filter. An effect can be obtained.
(4) Since the pressing force is concentrated on the tip of the rubber blade, it is possible to reliably remove the dust adhered firmly.

(Fourth embodiment)
In the first to third embodiments, an example has been described in which dust is removed by scanning while the wiper is in contact with the effective portion surface of the optical filter. In a fourth embodiment described below, an example is shown in which a knife edge wiper is scanned with a small amount away from the optical filter surface to remove dust. The configuration other than the wiper portion is the same as that of the first embodiment. Hereinafter, the configuration and operation of the fourth embodiment will be described with reference to FIG.

  FIG. 8 is a configuration diagram of the cleaning unit according to the fourth embodiment, and corresponds to FIG. 2 of the first embodiment. The wiper 431 provided in the cleaning unit 400 according to the fourth embodiment is a band-shaped rigid body whose upper edge and lower edge are knife edges, as shown in the perspective view of FIG. 8A and the cross-sectional view of FIG. It is a member. As shown in FIG. 8C, three hemispherical embossments 431a having a predetermined height are provided on the back surface of the wiper 431, that is, the contact surface with the optical filter. Here, the height of the emboss is set equal to or less than the size of dust harmful to the image sensor 15. In the present embodiment, the emboss height is 20 μm. Therefore, when the cleaning unit 400 of the present embodiment and the image sensor 15 including the optical filter 14 are combined, the tip of the emboss 431a comes into contact with the surface of the optical filter 14 as shown in FIG. Then, since a gap corresponding to the height of the emboss 431a is formed on the knife edge portion of the wiper 431 and the surface of the optical filter 14, dust larger than 20 μm is removed by scanning the wiper 431. Further, since the emboss 431a is provided outside the optical effective range of the optical filter 14, even if the surface of the optical filter 14 is scratched by the contact of the emboss 431a, there is no optical effect.

According to the above fourth embodiment, in addition to the following effects (1) and (2) similar to those of the first embodiment, the effects (3) and (4) can be obtained.
(1) Since both ends of the belt-shaped wiper are supported by nuts and the two nuts are driven at a constant speed by lead screws, respectively, the surface of the optical filter can be reliably scanned with a small driving force.
(2) Since the main mechanism for driving the wiper is disposed on the image sensor side of the optical filter surface and at a position facing the optical axis of the optical filter, the shutter mechanism or other optical element is provided immediately before the optical filter. This is effective for downsizing the apparatus.
(3) Since both ends of a rigid wiper having a knife edge and emboss are pressed against the optical filter using a leaf spring, dust of a predetermined size or more can be reliably removed.
(4) Since the wiper member does not come into contact with the optically effective area of the optical filter, there is no possibility that scratch marks will be generated in the effective area.

(Fifth embodiment)
In the first to fourth embodiments, an example in which the wiper mechanically removes dust from the optical filter has been described. In the fifth embodiment described below, an example is shown in which dust is removed using a remote force such as an electrostatic force. The configuration other than the wiper portion is the same as that of the first embodiment. Hereinafter, the configuration and operation of the fifth embodiment will be described with reference to FIG.

  FIG. 9 is a configuration diagram of the cleaning unit according to the fifth embodiment, and corresponds to FIG. 2 of the first embodiment. As shown in FIG. 9C, the wiper 531 provided in the cleaning unit 500 of the fifth embodiment has two opposing electrodes on the back surface of the band-shaped rigid member 531a, that is, the surface facing the optical filter 14. A flexible printed board 531b is bonded and fixed. Further, as shown in FIG. 9A, both ends of the wiper 531 are directly fixed and supported by the nuts 27 and 28. When the cleaning unit 500 and the image sensor 15 are assembled, as shown in FIG. 9B, the gap between the flexible printed circuit board 531b and the optical filter surface is adjusted to a predetermined amount, for example, 0.1 mm.

  In the above configuration, when the motor 24 is driven to scan the wiper 531 from top to bottom, a predetermined voltage is applied to the counter electrode of the flexible printed circuit board 531b. Then, an electric field is generated in a space including dust attached to the surface of the optical filter 14, and the dust is removed by the action of the electric field. Here, the action due to the electric field refers to suction and evacuation of charged dust by Coulomb force, suction of dust by gradient force, neutralization action of the optical filter surface by corona discharge, etc., and forms suitable for expressing each action This voltage may be applied.

According to the fifth embodiment described above, in addition to the following effects (1) and (2) similar to those of the first embodiment, the effect (3) can be obtained.
(1) Since both ends of the belt-shaped wiper are supported by nuts and the two nuts are driven at a constant speed by lead screws, respectively, the surface of the optical filter can be reliably scanned with a small driving force.
(2) Since the main mechanism for driving the wiper is disposed on the image sensor side of the optical filter surface and at a position facing the optical axis of the optical filter, the shutter mechanism or other optical element is provided immediately before the optical filter. This is effective for downsizing the apparatus.
(3) Since the wiper is scanned in a non-contact manner with respect to the optical filter, the wiper driving load is reduced, and miniaturization and power saving of each member including the driving motor can be achieved.

(Sixth embodiment)
In the first to fourth embodiments, an abutting force is generated between the wiper and the optical filter using an elastic member such as a leaf spring. In the sixth embodiment described below, an example is shown in which a friction torque acting between a lead screw and a nut, which is a driving means, is used as a pressing force of a wiper. The configuration other than the wiper and the nut portion is the same as that of the first embodiment. Hereinafter, the configuration and operation of the sixth embodiment will be described with reference to FIG.

  FIG. 10 is a configuration diagram of the cleaning unit in the sixth embodiment, and FIG. 10A is a perspective view of the cleaning unit 600 alone. In FIG. 10 (a), the wiper 631 is provided with electrostatic flocking on the back surface of a metal band-shaped rigid body member, like the wiper 31 of the first embodiment.

  Reference numerals 627 and 628 denote nuts which can be moved up and down by screwing with the lead screws 22 and 23, and support both ends of the wiper 631 to form a part of a drive member for driving the wiper up and down. Yes. Reference numerals 629 and 630 denote connecting pins which pivotally support both ends of the wiper 631 with respect to the nuts 627 and 628. Since these members are the same as those in the first embodiment, description thereof is omitted.

  In the above configuration, when the motor 24 is energized and the motor shaft 25 is rotated in the direction of the arrow in FIG. 10A, the rotation is caused by the lead screws 22 and 23 and the nut 627 via the four bevel gears 26a to 29d. , 628 are driven as follows.

  First, the lead screw 22 rotates counterclockwise and drives the nut 627 downward. Further, the lead screw 23 rotates clockwise, and the nut 628 is driven downward at the same speed as the nut 627. Then, the wiper 631 coupled by the connecting pins 629 and 630 is also translated and driven downward.

  Here, since friction torque acts on the screwed portion of the lead screw 22 and the nut 627, the nut 627 also generates counterclockwise rotational torque in addition to the downward driving force. Similarly, due to the friction torque acting on the threaded portion of the lead screw 23 and the nut 628, the nut 628 also generates a clockwise rotational torque in addition to the downward driving force. Therefore, when the wiper 631 is driven downward, a pressing force toward the optical filter 14 is generated at both ends of the wiper 631.

  FIG. 10B is an enlarged cross-sectional view of the vicinity of the wiper when the cleaning unit 600 and the image sensor 15 are coupled and the wiper 631 is driven downward (forward movement). As described above, a rightward force in the drawing acts on the wiper 631 due to the frictional torque of the nut, so that the flocking portion of the wiper 631 is driven downward while in contact with the surface of the optical filter 14. When the wiper 631 reaches the lower end, the wiper position detection device 33 detects this, reverses the motor 24, and the wiper 631 moves back upward. At this time, the friction torque generated at the screwed portions of the lead screws 22 and 23 and the nuts 627 and 628 is reversed from that during the forward movement. Accordingly, as shown in FIG. 10C, a force in a direction away from the optical filter 14 acts on both ends of the wiper 631. Here, a protruding stopper 627 a is provided outside the nut 627, and a protruding stopper 628 a is also provided outside the nut 628. The stoppers 627a and 628a are in contact with the inner surfaces of the side frames 21c and 21d, so that the rotation angles of the nuts 627 and 628 are limited. Accordingly, the distance between the wiper 631 and the optical filter 14 is also limited to a predetermined value, and the collision between the wiper 631 and the shutter 13 is avoided.

  FIG. 10D is an enlarged cross-sectional view of the vicinity of the wiper when the wiper 631 is driven upward (returned). As described above, since a force in the left direction in the drawing acts on the wiper 631 due to the friction torque of the nut, the flocking portion of the wiper 631 is driven upward while being away from the surface of the optical filter 14.

  When the wiper 631 returns to the initial position, that is, the upper end, the wiper position detection device 32 detects this, stops the motor 24, and completes one dust removal operation.

According to the above sixth embodiment, in addition to the following effects (1) and (2) similar to those of the first embodiment, the effects (3) and (4) can be obtained.
(1) Since both ends of the belt-shaped wiper are supported by nuts and the two nuts are driven at a constant speed by lead screws, respectively, the surface of the optical filter can be reliably scanned with a small driving force.
(2) Since the main mechanism for driving the wiper is disposed on the image sensor side of the optical filter surface and at a position facing the optical axis of the optical filter, the shutter mechanism or other optical element is provided immediately before the optical filter. This is effective for downsizing the apparatus.
(3) Since the contact force for pressing the wiper against the optical filter uses the frictional force generated at the nut screwing portion, the displacement dependency of the force, which is a defect of the spring, does not appear. Therefore, even if an error or variation occurs in the relative position between the cleaning unit and the optical filter, a constant pressing force can always be obtained.
(4) The wiper removes dust only when it is driven downward from above, and is separated from the optical filter during reverse driving, so that the wiped dust falls below the optical filter and does not accumulate upward. Therefore, it is possible to prevent the removed dust from reattaching to the optical filter.

  In addition, you may use the press mechanism by the friction torque of 6th Embodiment for the wiper of 3rd thru | or 5th Embodiment.

  The present invention provides an apparatus for reliably removing dust from an optical element and an imaging element by a small and simple mechanism, and is particularly effective for an imaging apparatus such as an electronic camera.

It is sectional drawing which shows the structure of the camera which is 1st Embodiment of the imaging device of this invention. It is explanatory drawing of the cleaning unit of 1st Embodiment. It is a block diagram which shows the circuit structure of the camera of 1st Embodiment. It is a flowchart which shows the dust removal process of 1st Embodiment. It is explanatory drawing of the cleaning unit of 2nd Embodiment. It is explanatory drawing of the structure of the wiper of 2nd Embodiment. It is explanatory drawing of the cleaning unit of 3rd Embodiment. It is explanatory drawing of the cleaning unit of 4th Embodiment. It is explanatory drawing of the cleaning unit of 5th Embodiment. It is explanatory drawing of the cleaning unit of 6th Embodiment.

Explanation of symbols

1 Camera body 2 Camera mount 3 Camera contact 4 LED
5 main mirror 6 main mirror holding frame 7 sub mirror 8 sub mirror holding frame 9 viewfinder screen 10 focus detection unit 11 penta roof prism 12 eyepiece 13 shutter 14 optical low-pass filter 15 image sensor 20, 200, 300, 400, 500, 600 cleaning unit 21 Cleaning unit frame 22, 23 Lead screw 24 Motor 26a, 26b, 26c, 26d Bevel gear 27, 28, 627, 628 Nut 31, 231, 331, 431, 531, 631 Wiper 41 Camera CPU
44 Display Drive Circuit 47 Cleaning Mechanism Drive Circuit 54 LED Drive Circuit 55 Image Sensor Drive Circuit 60 Display 80 Interchangeable Lens 81 Imaging Optical System 82 Lens Mount 83 Diaphragm Mechanism 84 Lens Side Contact 91 Lens CPU

Claims (9)

A foreign matter removing apparatus for removing foreign matter adhering to a surface to be cleaned which is a surface of an optical element,
A lead screw disposed outside the optical element;
A drive source for driving the lead screw;
A nut screwed into the lead screw;
A foreign matter removing member that is pivotally supported with respect to the nut and removes the foreign matter attached to the surface to be cleaned;
When the drive source drives the lead screw in the first direction, the nut is substantially uniformly disposed on the surface to be cleaned by the rotational frictional force between the lead screw and the nut. A foreign matter removing device characterized in that a pressing force acts on the surface. When the drive source drives the lead screw in the second direction, the nut is separated from the surface to be cleaned by the rotational frictional force between the lead screw and the nut. 2. The foreign matter removing apparatus according to claim 1, wherein force acts. The foreign matter removing member includes a band-shaped or bar-shaped main body disposed across the surface to be cleaned, and flocking provided on a side of the main body facing the surface to be cleaned. Item 3. The foreign matter removing apparatus according to Item 1 or 2. 4. When the drive source drives the lead screw in the second direction, the foreign matter removing member is in a state in which the flocking is separated from the surface to be cleaned by the separating force. 5. The foreign matter removing apparatus described. A foreign matter removing apparatus for removing foreign matter adhering to a surface to be cleaned which is a surface of an optical element,
A first lead screw disposed on one outer side of the optical element;
A second lead screw disposed on the other outer side of the optical element;
A drive source for driving the first lead screw and the second lead screw;
A first nut threadably engaged with the first lead screw;
A second nut threadably engaged with the second lead screw;
One end is pivotally supported with respect to the first nut and the other end is pivotally supported with respect to the second nut so as to remove foreign matter adhering to the surface to be cleaned. A foreign matter removing member that
When the drive source drives the first lead screw in the first direction and drives the second lead screw in the second direction, the first nut may include the first lead screw. And a force that presses one end of the foreign matter removing member substantially uniformly against the surface to be cleaned by a rotational friction force between the first nut and the first nut, and the second lead is applied to the second nut. A foreign matter removing apparatus, wherein a force that presses the other end of the foreign matter removing member substantially uniformly against the surface to be cleaned is exerted by a rotational frictional force between a screw and the second nut. When the driving source drives the first lead screw in the second direction and drives the second lead screw in the first direction, the first nut may include the first lead screw. And a force of separating one end of the foreign matter removing member from the surface to be cleaned is exerted by a rotational friction force between the first nut and the first nut, and the second lead screw and the second nut are connected to the second nut. The foreign matter removing apparatus according to claim 5, wherein a force that separates the other end of the foreign matter removing member from the surface to be cleaned acts by a rotational friction force between the second nut and the second nut. The foreign matter removing member includes a band-shaped or bar-shaped main body disposed across the surface to be cleaned, and flocking provided on a side of the main body facing the surface to be cleaned. Item 7. A foreign matter removing apparatus according to Item 5 or 6. When the drive source drives the first lead screw in the second direction and drives the second lead screw in the first direction, the foreign matter removing member causes the flocking to occur by the separating force. The foreign matter removing apparatus according to claim 7, wherein the foreign object removing apparatus is in a state of being separated from the surface to be cleaned. An imaging device comprising the foreign matter removing device according to any one of claims 1 to 8.

Images