JP4609663B2 - Imaging device - Google Patents

Description

  The present invention relates to an image pickup apparatus, and more particularly to an image pickup device that includes a solid-state image pickup device that picks up an image of a subject and can prevent adhesion of dust (floating particulate matter) on the solid-state image pickup device.

  Various solutions have been proposed for the problem of dust reflection in a captured image in an imaging apparatus equipped with an imaging element such as a digital camera. In Patent Document 1, it is proposed to provide a dustproof filter that is transparent and vibrated by a piezoelectric element between an imaging element and a shutter. According to this, by applying a voltage to the piezoelectric element, the transparent dustproof filter is vibrated, dust adhering to the dustproof filter is shaken off, and reflection of dust on the photographed image is prevented.

  Patent Document 2 proposes to dispose a transparent thin plate member on the back surface of the focal plane shutter on the image sensor side. According to this, when the dust generated by the opening and closing operation of the shutter is captured by the transparent thin plate member and the amount of dust attached to the thin plate member increases, the dust can be easily removed by replacing the thin plate member. can do.

  In Patent Document 3, it is proposed to provide a transparent protective member that protects the image sensor from dust and dust on the lens side from the shutter curtain. According to this, dust does not adhere to the image sensor, but adheres to the transparent protective member, and does not open the shutter curtain when cleaning the dust (because turbulence that moves the shutter curtain occurs and the dust tends to fly) The dust can be removed by cleaning only the member.

  Patent Document 4 proposes that an optical low-pass filter larger than the area of the image sensor can be moved in a direction perpendicular to the optical axis. According to this, by moving the optical low-pass filter during exposure, it is possible to blur the shape of dust and reduce the appearance of dust in the captured image.

  In Patent Document 5, it is proposed to arrange a sensor cover formed of a liquid crystal layer directly on an image sensor. This prevents dust from adhering to the image sensor during the manufacturing process.

Patent Document 6 describes a single-lens reflex camera using a liquid crystal as a shutter, whereby the lens optical system is reduced in size and thickness.
Japanese Patent Laid-Open No. 2003-348401 Japanese Patent Laid-Open No. 2003-23560 JP 2002-90842 A Japanese Patent Laid-Open No. 2002-10137 JP 2004-260357 A Japanese Patent Laid-Open No. 2003-344897

  However, the above patent document has the following drawbacks. In Patent Document 1, a dustproof filter and a driving circuit for vibration are necessary and expensive. In addition, relatively large dust (about several hundred μm) can be shaken off by vibration, but minute dust (about several tens of μm) cannot be shaken off. In order to prevent the minute dust on the dustproof filter from forming an image on the image sensor, it is necessary to increase the distance between the dustproof filter and the image sensor due to the mechanism.

  Patent Documents 2 and 3 are effective for dust generated when the shutter curtain is opened and closed, but not effective for dust suspended in the air (SPM: Suspended Particulate Matter). This SPM accounts for over 90% of trash). Therefore, the maintenance time (thin plate member replacement time) is the same as the current situation, and the thin plate member needs to be held and is expensive.

  In Patent Document 4, driving means for moving the optical low-pass filter is necessary, and the apparatus becomes expensive and the moving mechanism is necessary, so that the size is increased. In addition, since the maintenance time for garbage cleaning is not different from the current situation, the burden on the user cannot be reduced.

  In Patent Document 5, it is impossible to prevent dust from adhering to a completed image sensor, and in Patent Document 6, no measures are taken to prevent dust from being adhered.

  The present invention has been made in view of such circumstances, and prevents dust from being captured on a captured image or the like captured by the imaging apparatus, can obtain a high-quality image at low cost, and can be used for dust cleaning. An object of the present invention is to provide an imaging apparatus capable of extending the maintenance cycle.

In order to achieve the above object, an image pickup apparatus according to claim 1, a photographing optical system that forms an image of light from an incident subject, and an image formed by the photographing optical system is received by a light receiving surface and photoelectrically received. An image sensor to be converted, an optical filter disposed on the subject side with respect to the light receiving surface of the image sensor, and a super-water-repellent thin film formed on the surface; and the optical filter in contact with the peripheral surface of the optical filter a holding member for holding, Rutotomoni and a capturing means arranged at least on an object side of the optical filter to capture stray dust, the holding portion of the holding member abuts against the circumferential surface of the optical filter, The object-side surface of the optical filter is disposed at a position projecting toward the object side with respect to the object-side surface of the holding member, and the optical filter is disposed at the holding portion of the holding member. Gap penetrating in the thickness direction of the holding portion in order to prevent the retention of floating dust generated when physical cleaning of the optical filter between the circumferential surface of the formed, is characterized in that.

According to the present invention, by forming a super-water-repellent thin film on the surface of the optical filter disposed in the vicinity of the image sensor, it is possible to prevent adhesion of dust floating in the air and It is possible to provide a high quality photographed image over a long period of time. In addition, since the floating dust can be captured by the capturing means, the floating dust itself can be reduced, and adhesion of the floating dust to the optical filter can be further reduced. Further, since the object-side surface of the optical filter is disposed at a position protruding toward the object side with respect to the object-side surface of the holding member, the optical filter can be used for maintenance such as wiping off dust adhering to the optical filter. Since the structure does not allow dust to accumulate on the peripheral portion, maintenance work can be simplified and the maintenance cycle can be lengthened. In addition, when performing maintenance such as wiping off dust adhering to the optical filter, the dust that has not been wiped off enters the gap that does not affect the captured image (gap between the optical filter and the holding member), and dust accumulates around the optical filter. Since the structure does not, maintenance work can be simplified and the maintenance cycle can be lengthened. In addition, the peripheral surface of the holding portion of the holding member that comes into contact with the peripheral surface of the optical filter is uneven, and the optical filter can be easily held.
The imaging device according to claim 2 is the invention according to claim 1, further comprising a detachable optical finder, and capture means for capturing floating dust inside an exterior member of the optical finder. Furthermore, it is characterized by having prepared. ADVANTAGE OF THE INVENTION According to this invention, the floating dust in the inside of the removable optical finder can be reduced, and the malfunction which dust shows in a finder image is prevented.
According to a third aspect of the present invention, in the invention of the second aspect, a super water-repellent thin film is formed on a surface of a lens constituting the optical finder. According to the present invention, it is difficult for floating dust to adhere to the surface of the lens of the optical viewfinder, and the problem that dust is reflected in the viewfinder image is more effectively prevented.

The imaging device according to a fourth aspect is the invention according to the first , second, or third aspect , wherein the super water-repellent thin film has a water droplet contact angle of 150 degrees or more and a thickness of about 400 nm to about 500 nm. The light transmittance of the wavelength is 80% or more, and at least silicon or fluorine is included as a composition component. The present invention shows one mode of proper thin film conditions capable of preventing the adhesion of dust.

The imaging device according to claim 5 is the invention according to claim 1 , 2 , 3, or 4 , wherein the optical filter is held in a state of being sealed between a light receiving surface of the imaging element, and The super water-repellent thin film is formed at least on the surface of the optical filter on the subject side.

  The present invention shows that an optical filter on which a super-water-repellent thin film is formed is applied to an optical filter arranged in a structure that seals the light-receiving surface of an image sensor, and in that case, in the air This indicates that it is only necessary to form at least a super-water-repellent thin film on the exposed subject-side surface.

According to a sixth aspect of the present invention, in the invention according to any one of the first to fifth aspects, the capturing unit is an adhesive unit that adheres the floating dust. The present invention indicates that the capturing means is a means for capturing floating dust by adhesion, for example, applying adhesive to the wall surface of the space communicating with the optical filter, the entrance of floating dust, etc. A method such as affixing a coated tape can be considered.

According to a seventh aspect of the present invention, there is provided the imaging apparatus according to any one of the first to sixth aspects, wherein the response speed is 0 as a shutter that switches between a state in which a subject light flux is transmitted to the image sensor and a state in which the subject light beam is blocked. It is characterized in that .25ms from the liquid crystal with a liquid crystal shutter over constructed. According to the present invention, since a liquid crystal shutter that does not mechanically open and close is used, floating dust can be prevented from being generated.

According to an eighth aspect of the present invention, in the invention of the seventh aspect , the liquid crystal is a ferroelectric liquid crystal. Ferroelectric liquid crystals are known for their fast response characteristics.

An imaging apparatus according to a ninth aspect is the invention according to any one of the first to eighth aspects, comprising an interchangeable lens camera body and a lens barrel mounted and coupled to the camera body. The photographing optical system is disposed in the lens barrel, and the imaging element and the optical filter are disposed in the camera body. The present invention shows an aspect in which the inventions of claims 1 to 8 are applied to an electronic camera with interchangeable lenses.
An imaging device according to a tenth aspect is the imaging device according to the ninth aspect, wherein the imaging device is provided in an opening of the camera body to which the lens barrel is mounted, and the opening is opened. A barrier that opens and closes to a closed state, a detection unit that detects whether or not the lens barrel is attached to the camera body, and the lens barrel based on a detection result of the detection unit A barrier control means for setting the barrier in an open state when mounted on a camera body, and setting the barrier in a closed state when the lens barrel is not mounted on the camera body; It is characterized by having.

  According to the present invention, when the lens barrel is removed from the camera body, the opening of the camera body to which the lens barrel is mounted is blocked by the barrier, so that intrusion of dust into the camera body is prevented. .

An imaging device according to an eleventh aspect is characterized in that, in the invention according to the tenth aspect , a super water-repellent thin film is formed on the surface of the barrier. According to the present invention, since dust does not easily adhere to the barrier, it is possible to prevent the dust attached to the barrier from being caught in the camera body.

An imaging device according to a twelfth aspect of the present invention is the imaging device according to the ninth aspect, wherein the imaging device is a closing member that is provided at an opening of the camera body to which the lens barrel is mounted and closes the opening. It is characterized by comprising a closing member having a transmittance of 80% or more and having a super-water-repellent thin film formed on the surface.

  According to the present invention, when the lens barrel is removed from the camera body, the opening of the camera body to which the lens barrel is mounted is closed by the closing member, so that intrusion of dust into the camera body is prevented. Is done.

The imaging apparatus according to claim 13 is the invention according to claim 12, wherein the closure member is characterized in that an elastic member having elasticity. The present invention shows one embodiment of the closing member.

According to a fourteenth aspect of the present invention, there is provided the imaging device according to any one of the first to eighth aspects, wherein the imaging device is a lens-integrated digital still camera.

An imaging device according to a fifteenth aspect is the invention according to any one of the first to thirteenth aspects, wherein the imaging device is a microscope camera.

  According to the present invention, it is possible to prevent dust from being captured on a captured image or the like captured by the imaging apparatus, to obtain a high-quality image at low cost, and to increase the maintenance cycle of dust cleaning.

  The best mode for carrying out an imaging apparatus according to the present invention will be described below in detail with reference to the accompanying drawings.

  FIG. 1 is a side sectional view showing a first embodiment of an interchangeable lens single-lens reflex electronic camera (digital camera) to which the present invention is applied. The electronic camera (hereinafter referred to as a camera) shown in FIG. 1 includes a camera body 10 and a lens barrel 12. The lens barrel 12 is detachably attached to the camera body 10 by a mount 14 of the camera body 10. ing.

  The lens barrel 12 holds therein a photographic optical system 16 including a plurality of lenses and a driving mechanism thereof. The photographic optical system 16 transmits light from the subject so that the image of the subject is photoelectrically detected by the image sensor 18. An image is formed on the conversion surface (light receiving surface). The lens barrel 12 is the same as that generally used in a conventional camera or the like.

  Inside the camera body 10, a main mirror 22, a pentaprism 24, an eyepiece lens 26, and the like for bending a subject light beam transmitted through the photographing optical system 16 and guiding it to the eyepiece window 20 are disposed.

  The main mirror 22 is movably disposed between a position retracted from the optical axis 28 of the photographing optical system 16 and a predetermined position on the optical axis 28, and is disposed on the optical axis 28 in a normal state. The optical axis 28 is disposed at a predetermined angle, for example, an angle of 45 degrees. Thereby, when the camera body 10 is in a normal state, the subject light flux that has passed through the photographing optical system 16 is imaged on the focusing plate 30 with the optical axis 28 bent by the main mirror 22. The luminous flux is guided to the pentaprism 24 through a condenser lens 32 that improves the viewfinder visibility.

  The light beam guided to the pentaprism 24 is reflected so as to be an erect image in the pentaprism 24 and then guided to the eyepiece lens 26 so that the photographer can observe an optimum image by the eyepiece lens 26. Enlarged.

  On the other hand, when the camera is performing the photographing operation, the main mirror 22 moves to a predetermined position that is retracted from the optical axis 28 during the exposure operation. At the same time, by opening the front curtain 34 and the rear curtain 36 constituting the shutter (focal plane shutter), the subject luminous flux passes through the optical low-pass filter 38 installed on the subject side of the image sensor 18 and then the light receiving surface of the image sensor 18. To form an image.

  The optical low-pass filter 38 plays a role in preventing moiré or the like from being generated in the subject image data by reducing the spatial frequency component in the vicinity of the sampling spatial frequency component from the spatial frequency of the subject image.

  The subject image formed on the light receiving surface of the image sensor 18 is obtained by the image sensor 18 as an electric signal (image signal) after photoelectric conversion. The image signal obtained by the image sensor 18 is subjected to various signal processing by an electric circuit such as a signal processing circuit mounted on the circuit board 40 and is recorded on a recording medium such as a memory card.

  Next, the optical low-pass filter 38 will be described. As shown in FIG. 2, the optical low-pass filter 38 is configured by bonding a plurality of (two in this embodiment) birefringent plates 38b and 38c made of a conventional crystal, lithium niobate or the like, and a birefringent plate. A super-water-repellent thin film 38a is formed on the surface of the object side 38b. The super water-repellent thin film 38a is substantially transparent having a water droplet contact angle of 150 ° or more formed by means such as plasma CVD or sol-gel method, and having a transmittance of 80% or more with respect to light having a wavelength of about 400 to about 600 nm. The film is formed of a fluorine (F) film or a silane (SiH4) thin film having a thickness of about several tens of nm to several hundreds of nm. In general, the wavelength of visible light is about 380 nm to about 780 nm, but actually, if the transmittance is 80% or more in the range of about 400 nm to about 500 nm, there is no problem in the obtained captured image.

  According to the thin film 38a, even when floating dust (floating particulate matter (about several μm to several tens μm)) containing oil enters the inside of the camera body 10 when the lens barrel 12 is replaced, the floating dust. Since the water repellency is very high, floating dust is prevented from adhering to the surface of the thin film 38a. Therefore, there is an effect that a high-quality image can be provided at a low cost over a long period of time.

  In the above embodiment, the super-water-repellent thin film is formed on the surface of the optical low-pass filter 38 on the subject side (the subject-side surface of the birefringent plate 38b). It is possible to form a thin film, and even in that case, the same effect is obtained.

  FIG. 3 is a side sectional view showing a second embodiment of an interchangeable lens single-lens reflex electronic camera (digital camera) to which the present invention is applied. In FIG. 3, the same components as those in FIG. 1 are denoted by the same reference numerals as those in FIG.

  The subject luminous flux that has passed through the photographic optical system 16 is guided to the eyepiece window 20 by bending the optical axis 28 by the main mirror 22, and at the same time, part of it is transmitted and bent by the sub-mirror 50 behind the main mirror 22. Then, it is guided to the AF sensor 52 disposed at the bottom of the camera body 10. The AF sensor 52 is normally modularized together with a separator lens (not shown), and continues to measure the distance to the subject until immediately before the exposure operation, thereby providing a good captured image without focus deviation.

  In the present embodiment, the wall surface in the mirror box 54 in which the main mirror 22 and the sub mirror 50 are installed (FIG. 3 is a cross section of a portion where the subject side and the upper side of the mirror box 54 are opened, so that only the lower surface is provided. ), For example, adhesive UV curable adhesive or adhesive tape 56 coated with an acrylic adhesive having a shear adhesive strength of 700 N (20 nm / 20 mm: stainless steel) or more exposes the adhesive application surface. Glued in the state. Note that the adhesive may be directly applied to the wall surface in the mirror box 54.

  By adhering the adhesive tape 56 to the wall surface in the mirror box 54 or applying an adhesive, even if floating dust (floating particulate matter) enters the camera body 10 during lens replacement, Since it is captured at the entrance, it is possible to reduce floating dust from floating inside the camera body 10. Accordingly, it is possible to prevent floating dust from adhering more than the effect of preventing the floating dust from adhering to the super-water-repellent thin film 38a formed on the optical low-pass filter 38, and to provide a high-quality image at a low cost over a long period of time. Can do.

  At the same time, it is possible to prevent floating dust that has entered inside the camera body 10 from adhering to the separator lens of the AF sensor 52 present at the bottom of the camera body 10, and thus it is possible to prevent malfunction of the AF sensor 52. There is also an effect.

  FIG. 4 is a cross-sectional view showing a first embodiment of a holding mechanism for holding the optical low-pass filter 38 on which a super-water-repellent thin film is formed as in the first and second embodiments. FIG. 5 is an exploded perspective view of the components shown in FIG.

  As shown in FIG. 2, the optical low-pass filter 38 in which the super-water-repellent thin film 38a is formed at least on the surface on the subject side has a rectangular opening from the back side (image sensor side) as shown in FIGS. The rubber member 70 is fitted into a rubber member 70 having an elastic deformation 70 </ b> A, and the rubber member 70 is in close contact with a part of the back side of the peripheral surface of the optical low-pass filter 38 and a peripheral part of the back surface. Further, from the front side (subject side) of the optical low-pass filter 38, the optical low-pass filter 38 is fitted into a holding member 72 having a rectangular opening 72A and is regulated by contact between the rubber member 70 and the holding member 72. Is inserted into the opening 72 </ b> A of the holding member 72. As a result, the optical low-pass filter 38 is held by the holding member 72 at a position substantially determined with respect to the optical axis direction.

  On the other hand, the holding member 72 is attached to a plate-like fixing member 74 having a rectangular opening 74A by screws, and the fixing member 74 is connected to the signal processing circuit board via the plate-like member 76 to which the imaging element 18 is attached. 78 is assembled by screws. As a result, the optical low-pass filter 38 is disposed on the front side of the image sensor 18 and the space between the light receiving surface of the image sensor 18 and the rear surface of the optical low-pass filter 38 is maintained in a sealed state.

  By the way, if the camera is used for several years, even if the optical low-pass filter 38 is formed with the super-water-repellent thin film 38a, the floating dust (floating particulate matter) that has entered the camera body 10 is optically low-pass. In some cases, the optical low-pass filter 38 needs to be cleaned. When cleaning the optical low-pass filter 38, after removing the lens barrel 12 from the camera body 10, the mount 14 side of the camera body 10 is free of dust and contains alcohol or the like in a non-woven fabric, for example. It is necessary to wipe the surface of the optical low-pass filter 38.

  According to the holding mechanism for the optical low-pass filter 38 shown in FIGS. 4 and 5, floating dust attached to the surface of the optical low-pass filter 38 in such a cleaning operation can be easily removed. In other words, the optical low-pass filter 38 has a subject whose optical axis direction is greater than the front-side surface (subject-side surface) at the holding portion 72B of the holding member (the vicinity of the boundary contacting the peripheral surface of the optical low-pass filter 38). It is held in a state of protruding to the side. Therefore, when the surface of the optical low-pass filter is wiped with a non-woven cloth impregnated with alcohol for cleaning the optical low-pass filter 38, dust that cannot be removed without adhering to the cloth is collected in the corner of the optical low-pass filter 38. It can be easily removed without depositing. Even if dust accumulates, it is not affected because it is a step portion with the holding member 72 outside the surface of the optical low-pass filter 38. Conventionally, dust is likely to accumulate at the boundary between the optical low-pass filter 38 and the holding member 72 at the time of cleaning, and operation skill is required. However, in the case of the holding mechanism of the above-described embodiment, the optical low-pass filter 38 should be used. There is an advantage that the cleaning work can be easily performed even when the cleaning is required.

  4 and 5, the optical low-pass filter 38 is held in a state where the front side surface protrudes from the front side surface of the holding portion 72B of the holding member 72. The optical low-pass filter 38 may be held by the holding member 72 so that the front-side surface of the optical low-pass filter 38 and the front-side surface of the holding portion 72B of the holding member 72 are in the same position.

  FIG. 6 is a cross-sectional view showing a second embodiment of a holding mechanism for holding the optical low-pass filter 38 on which a super-water-repellent thin film is formed, and FIG. 7 is a structural member shown in FIG. FIG. The structure of the holding mechanism according to the second embodiment is substantially the same as the structure of the holding mechanism according to the first embodiment shown in FIGS. 4 and 5, and is the same as that shown in FIGS. Constituent members having similar actions are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIGS. 6 and 7, a plurality of grooves 72C, 72C,... Having a substantially semicircular cross section are formed in the left and right holding portions 72B of the holding member 72 of the optical low-pass filter 38. As a result, a partial gap is formed between the peripheral surface of the optical low-pass filter 38 and the holding member 72. Unlike the first embodiment, in the second embodiment, the position of the front side surface of the optical low-pass filter 38 and the front side surface of the holding portion 72B of the holding member 72 are the same. Similarly to the embodiment, the front-side surface of the optical low-pass filter 38 may protrude from the front-side surface of the holding portion 72B of the holding member 72.

  According to the holding mechanism of the second embodiment as described above, when the surface of the optical low-pass filter is wiped with a non-woven cloth impregnated with alcohol for cleaning the optical low-pass filter 38, dust is applied to the cloth. It adheres and is removed, or enters the grooves 72C, 72C,... Of the holding portion 72B of the holding member 72. Therefore, even when it is necessary to clean the optical low-pass filter 38, the cleaning operation can be easily performed, and dust can accumulate on the periphery of the optical low-pass filter 38 during the cleaning operation. Therefore, the cleaning operation can be simplified and the cleaning period can be greatly prolonged.

  6 and 7 show the case where the grooves 72C, 72C,... Of the holding portion 72B of the holding member 72 are provided only on the left and right, but this is not limiting, and for example, the left and right grooves 72C, 72C,. Similarly, a plurality of similar grooves may be provided on the upper and lower sides, or a plurality of similar grooves may be provided only on the upper and lower sides (it may be provided only on one side).

  Next, a third embodiment of an interchangeable lens single-lens reflex electronic camera (digital camera) to which the present invention is applied will be described. FIG. 8 is a side sectional view showing an electronic camera according to the third embodiment. In FIG. 8, the same components as those in FIG. 1 are denoted by the same reference numerals as those in FIG.

  In the present embodiment, a liquid crystal shutter 100 is installed instead of the mechanical shutter (the shutter comprising the front curtain 34 and the rear curtain 36) in the first embodiment of FIG. A normal camera has a structure in which a desired shutter speed (1/4000 seconds or more) can be obtained using a mechanical shutter. Also in the first embodiment shown in FIG. 1, the mechanism is such that two shutter curtains (the front curtain 34 and the rear curtain 36) are moved at high speed for exposure. However, in such a shutter operation, subtle dust is likely to be generated inside the camera body 10 when the shutter is opened and closed, and even if a super-water-repellent thin film 38a is added to the optical low-pass filter 38, generation of dust is prevented. It is not desirable from the viewpoint of doing.

  Therefore, by using liquid crystal (liquid crystal shutter 100) as a shutter as in this embodiment, generation of dust is prevented because there is no mechanical movement. The liquid crystal shutter 100 can be switched between a state in which a subject light beam is transmitted and a state in which it is blocked by controlling a voltage applied to the liquid crystal material, so that an action equivalent to the opening / closing operation of the mechanical shutter can be obtained. It has become. As the liquid crystal material of the liquid crystal shutter 100, a ferroelectric liquid crystal (ferroelectric liquid crystal) having a quick response is preferable, and a liquid crystal material capable of a high-speed response with a response speed of 0.25 ms or less is particularly desirable. For example, a ferroelectric liquid crystal material having such characteristics is produced by adding a chiral dopant having a structure as shown in FIG. 9A to a base liquid crystal composition containing no chiral compound. The chiral dopant for ferroelectric liquid crystal shown in FIG. 9A is a fluorine-containing photoactive compound, and has a structure in which the chiral part and the core part are connected by various binders such as ether and ester. Further, instead of the chiral dopant in FIG. 9A, as shown in FIG. 9B, a chiral dopant having an ether bond, a chiral dopant having a changed core structure, or a chiral having a changed core side chain length A dopant can also be used. In addition to the chiral dopant as shown in FIG. 9, a chiral dopant having a different fluorine position in the chiral side chain, a fluorine dopant used in the core side chain, or other liquid crystal materials may be used. May be.

  Next, a fourth embodiment of an interchangeable lens single-lens reflex electronic camera (digital camera) to which the present invention is applied will be described. FIG. 10 is a side sectional view showing an electronic camera according to the fourth embodiment. 10, the same components as those in FIG. 1 are denoted by the same reference numerals as those in FIG. 1, and description thereof is omitted. In the present embodiment, the optical viewfinder unit 102 including the eyepiece window 20 and the eyepiece lens 26 is configured to be detachable from the camera body 10. The optical viewfinder unit 102 includes a frame member (exterior member) 104 that holds the eyepiece window 20 and the eyepiece lens 26 and shields a portion other than the optical path through which the subject light flux passes. On the inner surface of the frame member 104, for example, similar to the wall surface of the mirror box 54 in the second embodiment of FIG. 3, an adhesive UV curable adhesive or a shear adhesive strength of 700 N (20 nm / 20 mm: stainless steel) The pressure-sensitive adhesive tape 106 coated with the above acrylic pressure-sensitive adhesive is adhered with the pressure-sensitive adhesive application surface exposed. Note that the adhesive may be directly applied to the inner surface of the frame member 104.

  A super water-repellent thin film having the same characteristics as the optical low-pass filter 38 is formed on the surface of each lens group constituting the eyepiece 26.

  According to the present embodiment, floating dust is prevented from floating inside the optical finder unit 102. Further, since dust is prevented from adhering to the eyepiece lens 26, a good subject image can be visually recognized. Furthermore, since the optical finder unit 102 itself can be replaced, even if dust is accumulated inside the optical finder unit 102, it can be repaired at low cost.

  Next, a fifth embodiment of an interchangeable lens single-lens reflex electronic camera (digital camera) to which the present invention is applied will be described. FIG. 11 shows a state in which the lens barrel 12 is attached to the camera body 10 in the present embodiment, and FIG. 12 is a side cross-sectional view of the electronic camera showing a state in which the lens barrel 12 is removed from the camera body 10. FIG. 11 and 12, the same components as those in FIG. 1 are denoted by the same reference numerals as those in FIG.

  In the present embodiment, a dust prevention barrier 110 is provided at the opening of the mount 14 to which the lens barrel 12 (interchangeable lens) of the camera body 10 is attached. When the lens barrel 12 is attached to the camera body 10 as shown in FIG. 11, the dust prevention barrier 110 is in a state of being retracted (opened) from the optical path through which the subject luminous flux passes, as shown in FIG. When the lens barrel 12 is removed from the camera main body 10, the lens barrel 12 is opened and closed so that the entire opening of the mount 14 is closed (closed state). The opening / closing operation of the dust prevention barrier 110 is performed by driving a motor 112. The dust prevention barrier 110 may be any mechanism such as a vertically moving barrier or a rotating barrier, and may be made of any material.

  On the other hand, a detection switch 114 for detecting whether or not the lens barrel 12 is mounted is embedded in the detachable ring on which the mount 14 is formed. The detection switch 114 outputs a detection signal (ON / OFF signal) indicating whether or not the lens barrel 12 is mounted, and the detection signal is read by a control circuit (not shown) mounted on the camera body 10. It is supposed to be. The control circuit controls the motor of the dust prevention barrier 110 based on the detection signal from the detection switch 114, and when it is detected that the lens barrel 12 is attached to the camera body 10 based on the detection signal, the control circuit When the prevention barrier 110 is set in an open state as shown in FIG. 11 and it is detected that the lens barrel 12 is detached from the camera body 10, the dust prevention barrier 110 is put in a closed state as shown in FIG. Set.

  In addition, super-water-repellent thin films having the same characteristics as the optical low-pass filter 38 are formed on both surfaces of the dust prevention barrier 110.

  According to the present embodiment, the provision of the dust prevention barrier 110 prevents the floating dust from entering the camera body 10 when the lens barrel 12 is attached or detached. In addition, by forming a super-water-repellent thin film on the dust prevention barrier 110, it is possible to prevent dust from getting inside the camera body 10 and attaching dust to the dust prevention barrier 110 when the dust prevention barrier 110 is opened and closed. .

  Next, a sixth embodiment of an interchangeable lens single-lens reflex electronic camera (digital camera) to which the present invention is applied will be described. FIG. 13 is a side sectional view showing a sixth embodiment of an interchangeable lens single-lens reflex type electronic camera (digital camera) to which the present invention is applied. In the present embodiment, a transparent elastic member 120 that closes the entire opening of the mount 14 is mounted on the inner side of the camera body 10 than the mount 14. The elastic member 120 preferably has a light transmittance of 80% or more. For example, the elastic member 120 is formed of a thin film material such as tin oxide (ITO) or indium zinc oxide (IZO) formed on PET (polyethylene terephthalate), and further has the same characteristics as the optical low-pass filter 38 on these. It has a structure in which a water-repellent thin film is formed.

  14A and 14B show an example of the structure of the elastic member 120. FIG. In FIG. 2A, a thin film of ITO (or IZO) 132 is formed on PET 130 (front surface), and a super-water-repellent thin film 134 is formed on the surface (front surface). In FIG. 5B, the front surface of PET 130 is configured in the same manner as in FIG. 6A, and ITO (or IZO) 136 is formed on the rear surface of PET 130 as in FIG. A super-water-repellent thin film 138 is formed on the rear surface.

  According to the present embodiment, it is possible to prevent floating dust caught when the lens barrel 12 is attached / detached from entering the inside of the camera body 10 and to adhere to the elastic member 120 and to obtain a good captured image. Is obtained. In addition, although the elastic member 120 has elasticity, it does not necessarily need to have elasticity.

  As mentioned above, each component related to prevention of dust generation and adhesion shown in each electronic camera from the first embodiment to the sixth embodiment is applied in any combination to one electronic camera. can do. Only one of the components may be applied.

  In the above embodiment, the case where the present invention is applied to a digital camera has been described as an example. However, the application of the present invention is not limited to this. For example, the present invention can be applied to all imaging apparatuses having an imaging element (a solid-state imaging element such as a CCD or a CMOS) in a video camera, a mobile phone with a camera, a camera for a microscope, and the like. In the above embodiment, the case where the present invention is applied to an interchangeable lens single-lens reflex camera has been described. However, the present invention can be applied to a camera that is not a single lens reflex camera, and the lens is not interchangeable. The present invention can also be applied to an integrated camera (such as a digital still camera).

  In the above embodiment, the case where the optical low-pass filter 18 is disposed as the optical filter disposed on the front side of the image sensor 18 has been described. However, the present embodiment is also applicable to the case where an optical filter other than the optical low-pass filter is disposed. The invention can be applied.

  Furthermore, in the above embodiment, the space between the optical low-pass filter 38 and the light-receiving surface of the image sensor 18 is hermetically sealed, thereby preventing floating dust from entering, and the back surface of the optical low-pass filter 38 and the image sensor 18. Although the floating dust is prevented from adhering to the light receiving surface, the present invention can be applied even to a structure in which floating dust enters the back side of the optical filter disposed on the front side of the image sensor 38. If a super-water-repellent thin film is formed on both the front and back of the optical filter, it is possible to prevent floating dust from adhering to the optical filter.

1 is a side sectional view showing a first embodiment of an interchangeable lens single-lens reflex type electronic camera (digital camera) to which the present invention is applied. The figure which showed the structure of the optical low-pass filter. Side surface sectional drawing which showed 2nd Embodiment of the electronic camera (digital camera) of a lens interchangeable single-lens reflex type to which this invention was applied. Sectional drawing which showed 1st Embodiment of the holding mechanism for hold | maintaining the optical low-pass filter in which the super-water-repellent thin film was formed. The disassembled perspective view which decomposed | disassembled and showed the structural member of FIG. Sectional drawing which showed 2nd Embodiment of the holding mechanism for hold | maintaining the optical low-pass filter in which the super-water-repellent thin film was formed. The disassembled perspective view which decomposed | disassembled and showed the structural member of FIG. FIG. 8 is a side sectional view showing a third embodiment of an interchangeable lens single-lens reflex electronic camera (digital camera) to which the present invention is applied. FIG. 9 is a diagram showing a chemical structure of a chiral dopant for a strong electric liquid crystal used as a liquid crystal material of a liquid crystal shutter. FIG. 10 is a side sectional view showing a fourth embodiment of an interchangeable lens single-lens reflex electronic camera (digital camera) to which the present invention is applied. FIG. 11 is a side sectional view showing a fifth embodiment of an interchangeable lens single-lens reflex type electronic camera (digital camera) to which the present invention is applied. The lens barrel is attached to the camera body. It is the figure which showed the state. FIG. 12 is a side sectional view showing a fifth embodiment of an interchangeable lens single-lens reflex electronic camera (digital camera) to which the present invention is applied, in which the lens barrel is removed from the camera body. It is the figure which showed the state. FIG. 13 is a side sectional view showing a sixth embodiment of an interchangeable lens single-lens reflex type electronic camera (digital camera) to which the present invention is applied. FIG. 14 is a view showing an example of the structure of the elastic member of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Camera body part, 12 ... Lens barrel, 14 ... Mount, 16 ... Imaging optical system, 18 ... Imaging element, 20 ... Eyepiece window, 22 ... Main mirror, 24 ... Pentaprism, 26 ... Eyepiece lens, 28 ... Light Axis 30 ... Focus plate 32 ... Condenser lens 34 ... Leading curtain 36 ... Rear curtain 38 ... Optical low-pass filter 38a ... Thin film 38b, 38c ... Birefringent plate 40 ... Circuit board 50 ... Sub mirror 52 ... AF sensor 54 ... Mirror box 56 ... Adhesive tape 70 ... Rubber member 72 ... Holding member 72C ... Groove 74 ... Fixing member 76 ... Plate member 78 ... Signal processing circuit board 100 ... Liquid crystal shutter DESCRIPTION OF SYMBOLS 102 ... Optical finder unit, 106 ... Adhesive tape, 110 ... Dust prevention barrier, 112 ... Motor, 114 ... Detection switch, 120 ... Elastic member

Claims (15)

An imaging optical system that forms an image of light from an incident subject;
An image sensor that receives and photoelectrically converts an image formed by the photographing optical system by a light receiving surface;
An optical filter disposed on the subject side with respect to the light receiving surface of the image sensor, and having a super-water-repellent thin film formed on the surface;
A holding member that holds the optical filter in contact with the peripheral surface of the optical filter;
Capture means disposed at least on the subject side of the optical filter to capture floating dust;
The equipped Rutotomoni,
In the holding portion of the holding member that contacts the peripheral surface of the optical filter, the surface on the subject side of the optical filter is disposed at a position protruding toward the subject side with respect to the subject side surface of the holding member,
In the holding portion of the holding member, there is a gap penetrating in the thickness direction of the holding portion in order to prevent stagnant floating dust generated when the optical filter is physically cleaned between the peripheral surface of the optical filter. Been formed,
An imaging apparatus characterized by that . Provided with a removable optical viewfinder, the inside of the exterior member of an optical finder, an imaging apparatus of claim 1, further comprising a trapping means for trapping airborne dust. The imaging apparatus according to claim 2 , wherein a super water-repellent thin film is formed on a surface of a lens constituting the optical finder. The super water-repellent thin film has a water droplet contact angle of 150 ° or more, a light transmittance of about 400 nm to about 500 nm, and a composition component containing at least silicon or fluorine. The imaging apparatus according to claim 1 , 2, or 3 . The optical filter is held in a state of being sealed with a light receiving surface of the imaging device, and the super water-repellent thin film is formed on at least a subject side surface of the optical filter. 1 , 2 , 3, or 4 imaging devices. The trapping means is an imaging device according to any one of the preceding claims, characterized in that an adhesive means for adhering the floating dust. As a shutter switching between a state to shield state that transmits the object light to the image sensing device, of claims 1 to 6, comprising the liquid crystal shutter over composed response speed 0.25ms following liquid crystal The imaging device of any one of them . 8. The image pickup apparatus according to claim 7 , wherein the liquid crystal is a ferroelectric liquid crystal. A lens-interchangeable camera Body of consists of a lens barrel that is mounted coupled to the camera the body, the imaging optical system is disposed in the lens inside the body, said optical filter and said image sensor is a camera present the imaging apparatus according to any one of claims 1-8, characterized in that arranged inside the body. Provided in an opening portion of the camera body before Symbol lens barrel is attached, and an open state in which opening the opening, a barrier opening and closing operation in the closed state of closing the opening,
Detecting means for detecting whether or not the lens barrel is attached to the camera body;
When the lens barrel is mounted on the camera body based on the detection result of the detection means, the barrier is set to an open state, and the lens barrel is not mounted on the camera body Includes barrier control means for setting the barrier to a closed state;
The imaging apparatus according to claim 9, further comprising: The imaging apparatus according to claim 10 , wherein a super-water-repellent thin film is formed on the surface of the barrier. Provided in an opening portion of the camera body before Symbol lens barrel is mounted, a closing member for closing the opening, a thin film of and superhydrophobic a light transmittance of 80% or more is formed on the surface The imaging apparatus according to claim 9, further comprising a closing member. The imaging apparatus according to claim 12 , wherein the closing member is an elastic member having elasticity. The imaging apparatus, an imaging apparatus according to any one of claims 1-8, characterized in that the lens is integral digital still camera. The imaging apparatus, an imaging apparatus according to any one of claims 1 to 13, which is a microscope camera.

Images