IMAGING APPARATUS

An imaging apparatus includes an optical filter, a holding member which holds the optical filter and which is movable between a first position where an imaging luminous flux passes through the optical filter and a second position where the imaging luminous flux does not pass through the optical filter, and an elastic member which relatively moves on a surface of the optical filter while being in contact with the surface during a movement of the holding member. A portion, on a surface of the holding member, where the elastic member comes into contact with when the holding portion is at the first position or the second position is rougher than the surface of the optical filter.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to an imaging apparatus such as a digital camera with a built-in optical filter.

Description of the Related Art

Recently, with improvements in moving image photography functions in digital cameras, more and more users are performing moving image photography using digital cameras with interchangeable lenses such as a mirrorless interchangeable lens camera. In addition, digital cameras capable of representing moving images by utilizing blurring and a wide dynamic range due to a combination of lenses and large-format sensors are being used. In photography in a bright environment such as outdoors in the daytime, image quality deterioration called blown-out highlights occurs when brightness exceeds an upper limit value of the dynamic range of the sensor and causes a loss in image information. While the image quality deterioration can be reduced by adjusting sensitivity of the sensor, there are cases where sensitivity cannot be sufficiently adjusted. In consideration thereof, generally, photography is performed by reducing a light amount of an imaging luminous flux that is incident to the sensor.

While methods of reducing a light amount of incident light of a sensor include reducing a lens diaphragm, since this method also increases depth of field, blurring expressions utilizing lens performance become difficult. In addition, the light amount of incident light of a sensor can also be reduced by increasing shutter speed. However, when imaging a subject moving at high speed, since increasing the shutter speed results in consecutive still images with little subject blur in each frame, a video (moving image) with flickers due to loss of smoothness may be obtained.

In consideration thereof, an ND (Neutral Density) filter (also referred to as a dark filter) is often used in moving image photography. The ND filter is a physical optical filter which reduces a light amount without significantly affecting color development in a captured image and is capable of increasing a degree of freedom by which a shutter speed or an aperture value can be changed and expanding a width of expression of moving image photography even in a bright imaging environment.

In addition, a camera with a built-in ND filter configured in such a manner that the ND filter is capable of advancing and retreating with respect to a sensor has been proposed. However, dust or the like inside of the camera may adhere to the ND filter when the ND filter moves inside of the camera.

In consideration thereof, as shown inFIG.9, a configuration in which a foreign object adhered to an ND filter built into a camera is removed by a cleaning plate is proposed (Japanese Patent Application Laid-open No. 2010-226526).FIG.9is a schematic configuration diagram of a foreign object removal apparatus900that is built into the camera according to Japanese Patent Application Laid-open No. 2010-226526. The foreign object removal apparatus900includes an ND filter901, a cleaning plate902, a holding portion903, a guide904, a lead screw905, adhesive members906and907, and a motor908.

One end of the cleaning plate902is connected to the holding portion903so as to come into contact with a surface of the ND filter901and another end of the cleaning plate902is engaged with the guide904. The holding portion903is engaged with the lead screw905and moves along the lead screw905as the lead screw905is rotated by a rotation of the motor908. In addition, the adhesive members906and907are arranged at positions sandwiching the ND filter901so as to be capable of coming into contact with the cleaning plate902. The cleaning plate902moves on the ND filter901and the adhesive members906and907with the movement of the holding portion903.

A foreign object that adheres to the surface of the ND filter901is first captured by the cleaning plate902and then captured by the adhesive members906and907when the cleaning plate902moves onto the adhesive members906and907.

However, with the foreign object removal apparatus according to Japanese Patent Application Laid-open No. 2010-226526, depending on adhesion of the adhesive members, a foreign object having been captured by the cleaning plate902may avoid being captured by the adhesive members and may return to the ND filter. In addition, increasing adhesion of the adhesive members906and907may prevent the cleaning plate902from moving smoothly and may end up damaging the cleaning plate902.

SUMMARY OF THE INVENTION

The present invention provides a technique for more suitably removing, in an imaging apparatus with a built-in optical filter, a foreign object adhered to the optical filter.

According to some embodiments, an imaging apparatus includes an optical filter, a holding member which holds the optical filter and which is movable between a first position where an imaging luminous flux passes through the optical filter and a second position where the imaging luminous flux does not pass through the optical filter, and an elastic member which relatively moves on a surface of the optical filter while being in contact with the surface during a movement of the holding member, wherein a portion, on a surface of the holding member, where the elastic member comes into contact with when the holding portion is at the first position or the second position is rougher than the surface of the optical filter.

DESCRIPTION OF THE EMBODIMENTS

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, it is to be understood that constituent elements described in the following embodiments are merely exemplary and that the technical scope of the present invention is not intended to be limited by any of the individual embodiments described below but to be defined by the scope of claims. In addition, configurations may be created by appropriately combining parts of the embodiments described below with each other.

A configuration of a camera that is an example of an imaging apparatus according to the present embodiment will be described with reference toFIGS.1A and1B.FIGS.1A and1Bare external perspective views of a camera100according to the present embodiment.FIG.1Ais a perspective view of the camera100as seen from a side (front side) where an imaging luminous flux is incident andFIG.1Bis a perspective view of the camera100as seen from an opposite side (rear side) to the side where the imaging luminous flux is incident. Note thatFIGS.1A and1Bshow a state where a photographic lens unit104(FIG.2) to be mounted to the camera100has been removed.

InFIG.1A, the camera100includes a grip portion101for a user to stably hold the camera100. A shutter button102that is a switch used to start imaging is provided in an upper part of the grip portion101. In addition, the camera100includes a grip portion304for gripping the camera in a different direction from the grip portion101. As shown inFIG.1A, a lens mount portion103is provided on a front surface of the camera100and enables the photographic lens unit104shown inFIG.2to be attached to and detached from the camera100.

In addition, a mount contact point105between the camera100and the photographic lens unit104electrically connects the camera100and the photographic lens unit104to each other, supplies power to the photographic lens unit104, and performs communication related to lens control and lens data using electric signals. When replacing a lens, a lens lock release button106is depressed to release engagement of the lens and enable the lens to be detached.

A power supply switch107is used when turning power of the camera on or off. In addition, the power supply switch107is also used when prohibiting an operation with respect to a specific operation member. A main electronic dial108and a sub electronic dial119are rotating operation members capable of rotating clockwise and counterclockwise and, by being rotationally operated, enable various setting values such as the aperture and the shutter speed to be changed. A mode switching dial109is an operating portion for switching among photography modes. As an example, the mode switching dial109is used to switch among various modes such as a shutter speed priority photography mode, an aperture value priority photography mode, and a moving image photography mode. A SET button110is a push button mainly used to determine a selected item and the like.

A liquid crystal monitor111displays various setting screens of the camera100, photographed images, and live view images. An electronic view finder112is a finder that can be used as an eyepiece and displays various setting screens of the camera100, photographed images, and live view images. A multifunction button113is a push button that can be used by the user to optionally assign switching among various settings related to photography.

A display panel114displays various setting states of the camera such as photography modes and an ISO sensitivity. In addition, the display panel114is displayed even in a state where power of the camera has been turned off. An accessory shoe115includes an accessory contact point116(FIG.2) and enables various accessories such as an external strobe light and an external microphone to be mounted thereto. A medium slot lid173can be opened and closed and, when opened, an external recording medium148(FIG.3) can be inserted into and extracted from an internal medium slot172(FIG.3). A battery143supplies power to the camera100.

Next, an electrical configuration and operations of the camera100according to the present embodiment will be described with reference toFIG.2.FIG.2is a block diagram showing a main electrical configuration of the camera100.

An MPU (Micro Processing Unit)130is a small central arithmetic processing device that is built into the camera100. An accessory communication control circuit118, a time measuring circuit131, a shutter drive circuit132, a switch sensing circuit133, and a power supply circuit134are connected to the MPU130. In addition, a battery check circuit135, a video signal processing circuit136, an optical filter drive circuit137, and a piezoelectric element drive circuit145are also connected to the MPU130.

The MPU130performs operation control of the various portions of the camera100, processes input information, and issues instructions and performs control with respect to various elements. The MPU130also includes an EEPROM (Electrically Erasable Programmable Read-Only Memory) and can store time information created by the time measuring circuit131and various pieces of setting information. In addition, the MPU130communicates with a lens control circuit138that is built into the photographic lens unit104via the mount contact point105. Accordingly, the MPU130performs operation control of a focusing lens141and an electromagnetically-driven diaphragm142via an AF drive circuit139and a diaphragm drive circuit140. Note that while only one focusing lens141is schematically shown inFIG.2, the photographic lens unit104may be constituted of a group of a large number of lenses.

The AF drive circuit139has, for example, a stepping motor (not illustrated) connected thereto and drives the focusing lens141. The MPU130calculates a focusing lens drive amount in accordance with a defocus amount detected using a focus signal read from an imaging element121. In addition, the MPU130transmits a focus command including the calculated focusing lens drive amount to the lens control circuit138.

The lens control circuit138having received the focus command controls driving of the focusing lens through the AF drive circuit139. Accordingly, automatic focusing (AF) is performed. The diaphragm drive circuit140has a diaphragm actuator such as a stepping motor (not illustrated) connected thereto and drives a plurality of diaphragm blades (not illustrated) which form a diaphragm opening in the electromagnetically-driven diaphragm142. In addition, when the plurality of diaphragm blades are driven, a size of the diaphragm opening changes and a light amount of the imaging luminous flux is adjusted.

The MPU130calculates a diaphragm drive amount from a brightness signal read from the imaging element121and transmits a diaphragm command including the calculated diaphragm drive amount to the lens control circuit138. In other words, the MPU130performs communication for controlling the electromagnetically-driven diaphragm142with respect to the lens control circuit138. The lens control circuit138having received the diaphragm command controls driving of the electromagnetically-driven diaphragm142through the diaphragm drive circuit140. Accordingly, an appropriate aperture value is automatically set.

A mechanical focal plane shutter150is driven by the shutter drive circuit132. During photography, by moving a front curtain shutter (not illustrated) and opening the shutter when a photographer depresses the shutter button102and moving a rear curtain shutter (not illustrated) and closing the shutter in accordance with a desired exposure time, the exposure time with respect to the imaging element121is controlled.

An optical filter160is an optical element which diffuses an imaging luminous flux incident to an imaging unit120of the camera100and which imparts a special effect to an image by attenuating light in a specific wavelength range. An ND (Neutral Density) filter which attenuates an incident light amount of the imaging luminous flux at a constant rate, a PL (Polarized Light) filter which suppresses reflected light using a polarizing film, a soft filter which diffuses light, or the like is used as the optical filter160. A relative position of the optical filter160with respect to the imaging unit120is changed by driving the optical filter160with the optical filter drive circuit137.

The imaging unit120is a unit which mainly integrates an optical low-pass filter122, an optical low-pass filter holding member123, a piezoelectric element124that is a piezoelectric member, and the imaging element121. The imaging element121photoelectrically converts a subject image and, in the present embodiment, the imaging element121is assumed to be a CMOS (Complementary Metal Oxide Semiconductor) sensor. The imaging element121is not limited to a CMOS sensor and imaging devices of various forms such as a CCD type or a CID type may be adopted as the imaging element121. The optical low-pass filter122arranged in a state preceding the imaging element121is a single rectangular birefringent plate made of quartz.

The piezoelectric element124is a single-plate piezoelectric element (piezo element) which is vibrated by the piezoelectric element drive circuit145under an instruction from the MPU130and which transmits the vibration to the optical low-pass filter122. Due to the vibration of the piezoelectric element124, fine dust adhered to the optical low-pass filter122can be shaken off.

The video signal processing circuit136is responsible for image processing in general including filter processing and data compression processing with respect to an electric signal obtained from the imaging element121. Image data for monitor display from the video signal processing circuit136is displayed on the liquid crystal monitor111and the electronic view finder112via a liquid crystal drive circuit144.

In addition, the video signal processing circuit136can also store image data in a buffer memory147through a memory controller146according to an instruction from the MPU130. Furthermore, the video signal processing circuit136can also perform image data compression processing such as JPEG. When photography is continuously performed such as during consecutive photography, image data may be temporarily stored in the buffer memory147and pieces of unprocessed image data can be sequentially read through the memory controller146. Accordingly, the video signal processing circuit136can sequentially perform image processing and compression processing regardless of an input rate of the image data.

The memory controller146includes a function of storing image data in the external recording medium148and a function of reading image data stored in the external recording medium148. Examples of the external recording medium148include an SD card and a CF card which can be mounted to and removed from a camera main body.

The switch sensing circuit133transmits an input signal to the MPU130in accordance with an operation state of each switch. A switch SW1(102a) is turned on by a first stroke (half-press) of the shutter button102. A switch SW2(102b) is turned on by a second stroke (full-press) of the shutter button102. When the switch SW2(102b) is turned on, an instruction to start photography is transmitted to the MPU130. In addition, the main electronic dial108, the mode switching dial109, the power supply switch107, the SET button110, the multifunction button113, and the like are connected to the switch sensing circuit133.

The MPU130performs information communication with the accessory communication control circuit118in order to use functions of an accessory unit (not illustrated) via the accessory contact point116. The power supply circuit134distributes and supplies power of the battery143to each element of the camera. In addition, the battery check circuit135is also connected to the battery143and conveys information on remaining battery life and the like of the battery143to the MPU130.

Next, an internal configuration of the camera100according to the present embodiment will be described with reference toFIG.3.FIG.3is an exploded perspective view of the camera100according to the present embodiment. An exterior of the camera100is mainly constituted of a front cover10, a top cover11, and a rear cover12.

The battery143is arranged in a lower part of the camera100and can be inserted and extracted in a direction of an arrow S51. In addition, the external recording medium148can be inserted in a direction of an arrow S52into the medium slot172provided in a side part of the camera100. The medium slot172includes a push-type lever and the external recording medium148can be extracted in the direction of the arrow S52by pushing the lever.

The lens mount portion103and the imaging unit120are provided on an optical axis1000of the camera100and an optical filter unit320is arranged between the lens mount portion103and the imaging unit120. A main substrate on which the MPU130and the like are provided is arranged between the imaging unit120and the rear cover12.

Next, a configuration of the optical filter unit320will be described with reference toFIG.4.FIG.4is an exploded perspective view of the optical filter unit320of the camera100according to the present embodiment.

Components that make up the optical filter unit320are mounted to a base member321. The optical filter160is held by an optical filter holding member322. The optical filter holding member322includes a rack gear322a.The optical filter holding member322is engaged with an upper rail323and a lower rail324which are guiding members and is capable of moving the optical filter160in a direction in which the upper rail323and the lower rail324extend.

A leaf spring member329is mounted to the base member321by a screw (not illustrated). In addition, an elastic member330is fixed by a double-sided tape or the like to an affixing portion329aof the leaf spring member329. Furthermore, an accumulating member332is mounted in a mounting portion329bof the leaf spring member329. A clingy material such as a double-sided tape is preferably used as the accumulating member332. An elastic member331is fixed to an affixing portion321aof the base member321in a similar manner to the elastic member330and is arranged on an opposite side to the elastic member330with the optical filter160in-between. In addition, the elastic members330and331are arranged outside of a region where an imaging luminous flux passes through the optical filter160.

Furthermore, the elastic members330and331are arranged so that sides opposite to an affixing surface come into contact with the optical filter160or rough surface portions322band322c(FIG.7C) of the optical filter holding member322. In addition, surfaces of the rough surface portions322band322c(FIG.7C) of the optical filter holding member322are rougher than the surface of the optical filter160and are made of irregular surfaces as will be described later.

As shown inFIG.4, a motor325for moving the optical filter holding member322with the rack gear322ais arranged in the optical filter unit320. A pinion gear325ais mounted to a drive shaft of the motor325. In addition, a first gear326, a second gear327, and a third gear328are rotatably mounted to shafts provided in the base member321. The motor325, the pinion gear325a,the first gear326, the second gear327, the third gear328, and the rack gear322afunction as actuators that move the optical filter holding member322.

Next, a movement of the optical filter160held by the optical filter holding member322in the optical filter unit320will be described with reference toFIGS.5A to5C.FIG.5Ashows a state where the optical filter160is inserted into an imaging optical path. When the optical filter160is arranged as shown inFIG.5A, an imaging luminous flux passes through the optical filter160.FIG.5Bshows a state midway through a movement of the optical filter160from a state of being inserted into the imaging optical path to a state of being retreated from the imaging optical path.FIG.5Cshows a state where the optical filter160has retreated from the imaging optical path. When the optical filter160is arranged as shown inFIG.5C, the imaging luminous flux does not pass through the optical filter160. The optical filter holding member322is configured so as to be movable between a position shown inFIG.5Aand a position shown inFIG.5B.

When the user depresses the multifunction button113in the insertion state shown inFIG.5A, the optical filter holding member322starts to move to the state where the optical filter160has retreated from the imaging optical path. At this point, the rotation of the motor325is transmitted to the rack gear322aof the optical filter holding member322via the first gear326, the second gear327, and the third gear328.

In addition, the optical filter holding member322on which the optical filter160is arranged is guided by the upper rail323and the lower rail324and moves from the position (FIG.5A) where the optical filter160is inserted into the imaging optical path to the position (FIG.5C) where the optical filter160has retreated from the imaging optical path. When the optical filter160moves to the position where the optical filter160has retreated from the imaging optical path due to the movement of the optical filter holding member322, a detection of the optical filter160by a sensor (not illustrated) causes the movements of the optical filter holding member322and the optical filter160to stop.

When the user inserts the optical filter160into the imaging optical path once again, the user depresses the multifunction button113in a state where the optical filter160is at the position shown inFIG.5C. The motor325rotates in a direction opposite to that of the operation described above and the optical filter holding member322moves to the position shown inFIG.5A. When the optical filter160moves to the position where the optical filter160is inserted into the imaging optical path, a detection of the optical filter160by a sensor (not illustrated) causes the movements of the optical filter holding member322and the optical filter160to stop.

Next, the elastic members330and331according to the present embodiment will be described. InFIGS.5A to5C, an effective area160aenclosed by a dotted line of the optical filter160is a region where an imaging luminous flux guided from the focusing lens141(FIG.2) passes through in the state shown inFIG.5Awhere the optical filter160is inserted into the imaging optical path. Therefore, a region outside of the effective area160ain the optical filter160is a region where the imaging luminous flux does not pass through in the state shown inFIG.5Awhere the optical filter160is inserted into the imaging optical path.

First, a case where the optical filter160moves from the position (FIG.5A: insertion state) where the optical filter160is inserted into the imaging optical path to the position (FIG.5C: retreated state) where the optical filter160has retreated from the imaging optical path will be described. At the position (FIG.5A) where the optical filter160is inserted into the imaging optical path, the elastic member330and the elastic member331are respectively in contact with the rough surface portion322band the rough surface portion322c(FIGS.7A to7E) of the optical filter holding member322.

During the movement of the optical filter holding member322from the position where the optical filter160is inserted into the imaging optical path to the position where the optical filter160has retreated from the imaging optical path, the elastic members330and331relatively move on the surface of the optical filter160while in contact with the surface of the optical filter160. In addition, together with the movement of the optical filter holding member322, a foreign object which is adhered to the surface of the optical filter160and which affects imaging is moved by the elastic members330and331. In this case, the elastic members330and331come into contact with the effective area160aof the optical filter160and moves the foreign object in the effective area160aduring the movement of the optical filter160from the insertion state (FIG.5A) to the retreated state (FIG.5C).

At this point, the foreign object adhered to the surface of the optical filter160is moved by adhering to an end330aof the elastic member330and an end331aof the elastic member331(FIG.7E). In a state where the optical filter160has retreated from the imaging optical path shown inFIG.5C, the end330aof the elastic member330and the end331aof the elastic member331are positioned outside of the effective area160a. Therefore, the foreign object adhered to the end330aof the elastic member330and the end331aof the elastic member331can be moved outside of the effective area160a.

Next, when the optical filter160moves from the retreated state (FIG.5C) to the insertion state (FIG.5A), the foreign object adhered to the optical filter160is similarly moved by adhering to an end330bof the elastic member330and an end331bof the elastic member331(FIG.7E). In a state where the optical filter160is inserted into the imaging optical path shown inFIG.5A, the elastic members330and331are respectively positioned in the rough surface portions322band322cthat are outside of the effective area160a.

A behavior of a foreign object moved to the rough surface portion322bby the elastic member330will now be described with reference toFIGS.6A to6D.

FIG.6Ais a diagram created by extracting the optical filter160, the optical filter holding member322, and the accumulating member332from the optical filter unit320.FIG.6Bis an enlarged view of a rectangular portion denoted by G inFIG.6A.FIG.6Cis an enlarged view of a cross section taken along line I-I inFIG.6A.FIG.6Dis an enlarged view of a cross section taken along line J-J inFIG.6A. In addition, inFIGS.6A to6D, a movement direction of the optical filter holding member322when the optical filter160moves from the retreated state (FIG.5C) to the insertion state (FIG.5A) is depicted by an arrow D1. Furthermore, a movement direction of the optical filter holding member322when the optical filter160moves from the insertion state (FIG.5A) to the retreated state (FIG.5C) is depicted by an arrow D2. Moreover, inFIGS.6A to6D, assuming a case where an imaging luminous flux passes through the optical filter160in a direction perpendicular to the direction of gravitational force, the direction of gravitational force at this point is depicted by an arrow D3.

When the optical filter160moves from the retreated state (FIG.5C) to the insertion state (FIG.5A), the optical filter holding member322moves in the direction depicted by the arrow D1. At this point, a foreign object adhered to the optical filter160is moved to the rough surface portion322bof the optical filter holding member322that is outside of the optical filter160.

In the present embodiment, as shown inFIG.6B, an irregular surface is formed in the rough surface portion322bof the optical filter holding member322. InFIG.6B, a hatching part with a grid pattern is a protrusion that protrudes further toward a near side in a direction of the paper plane than a portion without the hatching part. Furthermore, a plurality of grooves322eare formed by protrusions and depressions (portions that are not hatching parts) in the rough surface portion322b.Each groove322eincludes a wall portion322fextending in a direction that obliquely intersects with the direction D2on a far side (a side of the direction D2) from the optical filter160. In addition, the groove322eincludes a saw-shaped wall portion322gextending in the extending direction of the wall portion322fon a near side (a side of the direction D1) to the optical filter160. The wall portion322gis formed so as to alternately connect a first portion322hextending in the direction of gravitational force D3that is perpendicular to the movement direction of the optical filter holding member322and a second portion322iextending in a direction that intersects with the direction of gravitational force D3. InFIG.6B, as an example, foreign objects accumulated on the end330bof the elastic member330and moved to the rough surface portion322bare depicted as foreign objects G1and G2.

When the optical filter holding member322moves in the direction D1, the foreign object adhered to the elastic member330moves into the groove322ein the rough surface portion322b(foreign object G2). The elastic member330is in contact with the rough surface portion322band the foreign object G2remains in contact with the elastic member330even after moving to the groove322e.In addition, when the optical filter holding member322further moves in the direction of the arrow D1, the foreign object G2is moved in the direction of the arrow D2by the elastic member330and collides with the wall portion322fof the groove322e.Subsequently, the foreign object G2moves in a direction of an arrow1001along the wall portion322fwith the movement of the optical filter holding member322.

In addition, when the optical filter160moves from the insertion state (FIG.5A) to the retreated state (FIG.5C), the optical filter holding member322moves in the direction depicted by the arrow D2. At this point, the foreign object G1adhered to the elastic member330is moved in the direction of the arrow D1by the elastic member330and collides with the first portion322hof the wall portion322gof the groove322e. Alternatively, the foreign object G1is moved in the direction of the arrow D1by the elastic member330, collides with the second portion322i,and moved along the second portion322ito the first portion322h.Since the first portion322his a wall portion extending in the direction of gravitational force D3or, in other words, a direction perpendicular to the movement direction D2of the optical filter holding member322, the foreign object G1remains in contact with the first portion322hand does not move even when the optical filter holding member322moves. Therefore, the foreign object G1remains in the rough surface portion322band is prevented from returning to the optical filter160. As described above, according to the present embodiment, a foreign object of the optical filter160which is adhered to the elastic member330is moved to the groove322eformed in the rough surface portion322bof the optical filter holding member322and a phenomenon in which the foreign object returns from the groove322eto the optical filter160is suppressed.

Next, a movement of the foreign object G2shown inFIG.6Bwill now be described with reference to the sectional view inFIG.6C. InFIG.6C, moved positions of the foreign object G2shown inFIG.6Bare denoted by G3, G4, G5, and G6. As shown inFIG.6C, the accumulating member332for accumulating foreign objects of the optical filter160having been moved by the elastic member330is provided on a side of a direction perpendicular to the movement direction of the optical filter holding member322or, in other words, a side of the direction of gravitational force D3with respect to the rough surface portion322b.

When the optical filter holding member322is repetitively moved between the insertion state and the retreated state of the optical filter160, inFIG.6C, the foreign object G2moves in a direction of an arrow1002along the wall portion322ffrom the position G3. In addition, the foreign object G2reaches the position G4at an upper end of an inclined portion322dof the optical filter holding member322. The foreign object G2having moved to the position G4moves in a direction of an arrow1003along an inclined surface of the inclined portion322dand reaches the position G5at a lower end of the inclined portion322d.The foreign object G2having moved to the position G5moves in a direction of an arrow1004from the inclined portion322dand is accumulated on a surface of the accumulating member332(position G6).

As described above, according to the present embodiment, a foreign object adhered to the optical filter160is moved into the groove322eof the rough surface portion322bby the elastic member330and subsequently accumulated by the accumulating member332. In addition, as shown inFIG.5B, a width w2of the accumulating member332is set larger than a width w1of the elastic member330in the movement direction of the optical filter holding member322. Accordingly, even when a foreign object adhered to the ends330aand330bof the elastic member330drops from the elastic member330during a movement of the optical filter holding member322, the foreign object can be caught by the accumulating member332. Note that an inclined portion and an accumulating member similar to the inclined portion322dand the accumulating member332described above are also provided on an opposite side with the optical filter holding member322in-between. Accordingly, a foreign object moved to the rough surface portion322cis accumulated by the accumulating member from the rough surface portion322cvia the inclined portion in a similar manner to a foreign object moved to the rough surface portion322b.

In addition, as shown inFIG.6D, in the optical filter holding member322, depressions322jand322nare formed between the optical filter160and the rough surface portions322band322c.Furthermore, the depressions322jand322nhave inclined surfaces322kand322mthat rise toward the rough surface portions322band322cfrom the optical filter160.

Hereinafter, while a description will be given with a focus on a relationship among the optical filter160, the rough surface portion322b,the inclined surface322k, the depression322j,and a foreign object, a relationship among the optical filter160, the rough surface portion322c,the inclined surface322m,the depression322n,and a foreign object can also be described in a similar manner. InFIG.6D, a direction in which an imaging luminous flux passes through the optical filter160is denoted by a direction D4. As shown inFIG.6D, the inclined surface322kis formed in the depression322jthat is depressed in the direction D4with respect to the surface of the optical filter160.

When the optical filter160moves from the insertion state (FIG.5A) to the retreated state (FIG.5C), a foreign object having been moved into the groove322eof the rough surface portion322bmay move outside of the groove322ewhile remaining adhered to the elastic member330and may move to the side of the optical filter160. In this case, as shown inFIG.6D, the foreign object having been moved outside of the groove322emoves in the direction of the arrow D1along the inclined surface322kand accumulates inside of the depression322jas depicted by a foreign object G7. As shown inFIG.6D, on a cross section of the optical filter holding member322made of a surface parallel to the direction of the arrow D4, the depression322jis formed to be lower than the surface of the optical filter160and the surface of the rough surface portion322b.Therefore, in the present embodiment, by causing a foreign object having been moved to the rough surface portion322bby the elastic member330to be accumulated inside of the depression322j,the foreign object can be prevented from returning once again to the optical filter160.

A phenomenon of a foreign object having been moved outside of the groove322ereturning to the optical filter160can be more suppressed when widths of the inclined surfaces322kand322min the movement direction of the optical filter holding member322are wider. In addition, a foreign object is more readily moved to the rough surface portions322band322cby the elastic members330and331when the inclined surfaces322kand322mare more gradual or, in other words, when gradients of the inclined surfaces322kand322mare smaller. Ranges in which the depressions322jand322nare formed and widths and gradients of the inclined surfaces322kand322min the optical filter holding member322may be appropriately determined according to sizes of the optical filter holding member322and the optical filter160that are built into the camera100and according to an arrangement of components of various parts.

While the behavior of a foreign object on the side of the elastic member330has been described above with reference toFIGS.6A to6D, the optical filter holding member322includes constituent elements similar to those described above in the elastic member331provided on an opposite side with the optical filter160in-between. Therefore, a foreign object of the optical filter160adhered to the elastic member331exhibits similar behavior to that described above.

Next, a biasing relationship among the optical filter160, the optical filter holding member322, and the elastic members330and331will be described with reference toFIGS.7A to7E.FIG.7Ais a view of the camera100as seen from a rear side in a state where the rear cover12has been removed.

FIG.7Bis a sectional view taken along line B-B inFIG.7Ain the insertion state (FIG.5A) of the optical filter160.FIG.7Cis an enlarged view of a portion enclosed by a circle denoted by X inFIG.7Bfor the purpose of illustration.FIG.7Dis a sectional view taken along line B-B inFIG.7Ain the retreated state (FIG.5C) of the optical filter160.FIG.7Eis an enlarged view of a portion enclosed by a circle denoted by Y inFIG.7Dfor the purpose of illustration.

As shown inFIGS.7B and7C, when the optical filter160is in the insertion state, the elastic members330and331are respectively in contact with the rough surface portions322band322cof the optical filter holding member322. The leaf spring member329biases the elastic member330in the direction of the optical filter holding member322. In addition, due to the optical filter holding member322pushing back the elastic member331in the direction of the leaf spring member329against a biasing force of the leaf spring member329, equilibrium is established between the elastic members330and331.

As shown inFIG.7D, when the optical filter160is in the retreated state, the optical filter160is caused to retreat to a position between the grip portion101and the medium slot172or a main substrate180by the optical filter holding member322. In addition, as shown inFIGS.7D and7E, when the optical filter160is in the retreated state, the elastic members330and331are in contact with the optical filter160. The leaf spring member329biases the elastic member330in the direction of the optical filter holding member322. In addition, due to the optical filter holding member322pushing back the elastic member331in the direction of the leaf spring member329against the biasing force of the leaf spring member329, equilibrium is established between the elastic members330and331.

In this case, sounds and vibrations that occur when the optical filter holding member322moves such as motor sounds and minute vibrations due to meshing of the gears are transmitted to the elastic members330and331by the optical filter160or the optical filter holding member322and absorbed by the elastic members330and331. Therefore, the vibrations and the sounds that occur when the optical filter holding member322moves are hardly transmitted to the user using the camera100.

As described above, according to the present embodiment, the camera100which has a built-in optical filter and which is capable of more suitably removing a foreign object adhered to the optical filter160can be provided without having to enlarge a conventional interchangeable lens camera.

Next, a modification of the embodiment described above will be described with reference toFIG.8. It should be noted that, in the following description, components similar to those of the camera100according to the embodiment described above will be denoted by the same reference signs and illustrations and detailed descriptions thereof will be omitted and components that differ from the embodiment described above will be described.FIG.8is a diagram showing an optical filter holding member1322built into the camera100according to the present modification.FIG.8is a view which corresponds toFIG.6Aand which is created by extracting the optical filter160, the optical filter holding member1322, and the accumulating member332from the optical filter unit320.

Due to a movement of the optical filter holding member1322in a direction of an arrow D1, the optical filter160is moved from a position where the optical filter160is retreated from an imaging optical path to a position where the optical filter160is inserted into the imaging optical path. In addition, due to a movement of the optical filter holding member1322in a direction of an arrow D2, the optical filter160is moved from the position where the optical filter160is inserted into the imaging optical path to the position where the optical filter160is retreated from the imaging optical path. Furthermore, in the optical filter holding member1322, rough surface portions1322dand1322bare respectively arranged on a side of the direction D1and a side of the direction D2with respect to the optical filter160. Note that in the optical filter holding member1322, rough surface portions configured in a similar manner to the rough surface portions1322band1322dare respectively arranged on opposite sides to the rough surface portions1322band1322dwith the optical filter holding member1322in-between.

In the present modification, when the optical filter160is in the insertion state, the elastic member330is at a position where the elastic member330comes into contact with the rough surface portion1322d.In addition, when the optical filter160moves from the insertion state to the retreated state, the optical filter holding member1322moves in the direction depicted by the arrow D2. At this point, the elastic member330relatively moves on the surface of the optical filter160from the rough surface portion1322dwith the movement of the optical filter holding member1322and, when the optical filter160assumes the retreated state, moves to a position where the elastic member330comes into contact with the rough surface portion1322b.Therefore, when the optical filter160moves from the insertion state to the retreated state, a foreign object on the surface of the optical filter160adheres to the elastic member330and is moved to the rough surface portion1322b.

On the other hand, when the optical filter160moves from the retreated state to the insertion state, the optical filter holding member1322moves in the direction depicted by the arrow D1. At this point, the elastic member330relatively moves on the surface of the optical filter160from the rough surface portion1322bwith the movement of the optical filter holding member1322and, when the optical filter160assumes the insertion state, moves to a position where the elastic member330comes into contact with the rough surface portion1322d.Therefore, when the optical filter160moves from the retreated state to the insertion state, a foreign object on the surface of the optical filter160adheres to the elastic member330and is moved to the rough surface portion1322d.

Since behaviors of foreign objects having been moved to the rough surface portions1322band1322dare similar to the embodiment described above, a detailed description will be omitted. In addition, the elastic member331is arranged on an opposite side to the elastic member330with the optical filter160in-between. Since movements of the elastic member331and behaviors of a foreign object are similar to the case of the elastic member330, a detailed description will be omitted.

Therefore, according to the present modification, since a foreign object of the optical filter160moves to the rough surface portions1322band1322devery time the optical filter160is switched between the insertion state and the retreated state, an effect of more reliably removing a foreign object of the optical filter160can be expected.

According to the present invention, in an imaging apparatus with a built-in optical filter, a foreign object adhered to the optical filter can be more suitably removed.

This application claims the benefit of Japanese Patent Application No. 2023-120478, filed on Jul. 25, 2023, which is hereby incorporated by reference herein in its entirety.