JP2009198693A - Imaging apparatus, camera, and method for manufacturing imaging apparatus - Google Patents

Abstract

An imaging device and the like that can prevent dust from adhering to members in an optical path.
[Solution]
An imaging unit 38 that captures an image by an optical system, a base material 36 that is provided opposite to the imaging unit and has optical transparency, and a surface of the base material that is opposite to a side where the imaging unit is disposed. The imaging device which has the particle layer 40 containing the some particle | grains 40a with which the surface of the side was equipped, and the electroconductive layer 42 provided between the said base material and the said particle layer.
[Selection] Figure 2

Description

  The present invention relates to an imaging device, a camera, and a manufacturing method of the imaging device, and more particularly to an imaging device that can prevent dust from adhering to members in an optical path.

  In an optical apparatus having an imaging device typified by a digital single-lens reflex camera, there may be a problem that dust adheres to a translucent member in an optical path and the dust appears in a photographed image.

  As a conventional technique for solving such a problem, there has been known an imaging apparatus having an optical element in which fine particles of a single layer are arranged on the surface on the object side and dust is prevented from adhering (see Patent Document 1). .

However, an optical element in which fine particles of a single layer are arranged may cause a part of the layer to be lost due to a physical impact, for example, due to a cleaning operation or the like, which causes a problem that dust adheres to the missing part of the film. It was. Further, the optical elements related to the prior art cannot sufficiently prevent the adhesion of dust mainly due to electrostatic force, which is a problem.
JP 2007-135005 A

  The present invention has been made in view of such circumstances, and an object thereof is to provide an imaging device or the like that can prevent dust from adhering to members in an optical path.

In order to solve the above problems, an imaging apparatus according to the present invention provides:
An imaging unit (38) for imaging an image by an optical system;
A base material (36) provided opposite to the imaging unit and having optical transparency;
A particle layer (40) including a plurality of particles (40a) provided on the surface opposite to the side on which the imaging unit is disposed, of the surface of the substrate;
It has the conductive layer (42) provided between the said base material and the said particle layer, It is characterized by the above-mentioned.

  For example, the particles may have water repellency.

  Further, for example, the particle layer may have a structure in which the particles are gathered in a multilayer shape.

  Further, for example, an adhesive layer (44) for fixing the particles to the conductive layer may be formed on the surface of the conductive layer on the particle layer side.

  For example, the conductive layer may not contain the particles.

  For example, the layer thickness of the particle layer may be larger than the average particle diameter of the particles.

  For example, the average particle diameter of the particles may be 5 nm or more and 200 nm or less.

  In addition, for example, the particles may contain at least one of silicon and fluorine.

  The camera according to the present invention includes any one of the imaging devices described above.

  In the manufacturing method of an imaging device according to the present invention, a conductive layer (42) having conductivity is formed on a base material (36) that transmits light, and particles (40a) are formed in layers on the conductive layer. It is characterized by doing.

  In addition, for example, in the method for manufacturing an imaging device according to the present invention, the step of forming particles in a layer shape on the conductive layer may be performed a plurality of times.

  In the above description, in order to explain the present invention in an easy-to-understand manner, the description is made in association with the reference numerals of the drawings showing the embodiments. However, the present invention is not limited to this. The configuration of the embodiment described later may be improved as appropriate, or at least a part of the configuration may be replaced with another component. Further, the configuration requirements that are not particularly limited with respect to the arrangement are not limited to the arrangement disclosed in the embodiment, and can be arranged at a position where the function can be achieved.

Hereinafter, the present invention will be described based on embodiments shown in the drawings. Note that the members shown in each drawing are partially exaggerated for convenience of explanation.
FIG. 1 is a schematic cross-sectional view of a digital single-lens reflex camera including an imaging device according to first to third embodiments of the present invention.
FIG. 2 is an enlarged view of a main part of a dustproof filter provided in the imaging apparatus according to the first embodiment of the present invention.
FIG. 3 is an enlarged view of a main part of a dustproof filter provided in an imaging apparatus according to the second embodiment of the present invention.
FIG. 4 is an enlarged view of a main part of a dustproof filter provided in an imaging apparatus according to the third embodiment of the present invention. FIG. 5 is a schematic cross-sectional view of a digital single lens reflex camera including the imaging apparatus according to the fourth embodiment of the present invention. Figure,
FIG. 6 is a schematic cross-sectional view of a digital single-lens reflex camera including an imaging apparatus according to the fifth embodiment of the present invention.
First embodiment

  FIG. 1 is a schematic cross-sectional view of a digital single-lens reflex camera equipped with an imaging unit 30 according to the first embodiment of the present invention, and shows a side cross-section of the camera body 4. An opening 8 is formed in the housing 6 of the camera body 4, and a lens mount 10 is formed around the opening 8. At the time of photographing, an interchangeable lens (not shown) is installed so as to cover the opening 8, and photographing light guided by the interchangeable lens is introduced into the housing 6.

  In the housing 6 of the camera body 4, a quick return mirror 12, a finder screen 14, a pentaprism 16, an eyepiece lens 22, a shutter 20, an imaging unit 30, and the like are provided.

  The imaging unit 30 includes a dustproof filter 32 and an imaging element 38. The image sensor 38 has a light receiving surface for receiving photographing light on the surface on the lens mount 10 side (X-axis negative direction side) to which the interchangeable lens is attached. The dust filter 32 is disposed on the X axis negative direction side of the image sensor 38 so as to cover the light receiving surface of the image sensor 38. Accordingly, when the shutter 20 is opened at the time of photographing, the photographing light that has passed through the shutter 20 passes through the dust filter 32 and then enters the light receiving surface of the image sensor 38 and is photoelectrically exchanged by the image sensor 38.

  Note that the arrangement of each member will be described with the direction in which the imaging light introduced by the interchangeable lens installed so as to cover the opening 8 travels toward the imaging element 38 is the positive direction of the X axis. Further, the description will be made assuming that the direction in which the photographing light reflected by the quick return mirror 12 travels toward the pentaprism 16 is the positive direction of the Z axis, the X axis direction, and the direction perpendicular to the Z axis direction is the Y direction.

  The dust filter 32 has a base material portion 36, a fine particle layer 40, and a conductive layer 42. The base material portion 36 is formed on the image sensor 38 side of the dust filter 32 and is fixed so as to be in close contact with the light receiving surface of the image sensor 38 via an adhesive layer or the like. The base material portion 36 according to the present embodiment is an optical low-pass filter that prevents generation of false colors (color moire) during imaging.

  FIG. 2 is an enlarged view of a main part of the dustproof filter 32 provided in the imaging apparatus shown in FIG. The dustproof filter 32 has a fine particle layer 40 and a conductive layer 42 on the surface of the base material portion 36 opposite to the side on which the imaging element 38 is disposed, of the surface of the base material portion 36. The fine particle layer 40 is formed by collecting fine particles 40a in layers.

  On the outermost surface 40b of the fine particle layer 40, fine irregularities are formed along the surface shape of the individual fine particles 40a. Here, the size of the fine particles 40a is not particularly limited, but the average particle size of the fine particles 40a is preferably 5 nm to 200 nm. By making the particle size of the fine particles 40a larger than a predetermined value, it becomes easier to obtain the characteristics of the fine particles 40a described later, and by making the particle size smaller than the predetermined value, the photographing light is prevented from being excessively scattered by the fine particles 40a. it can.

  The fine particle layer 40 is formed by collecting fine particles 40a in a layered form, and preferably has a structure in which the fine particles 40a are collected in multiple layers as shown in FIG. If the fine particle layer 40 has a multilayer structure, when the fine particles 40a on the outermost surface 40b of the fine particle layer 40 are peeled off due to physical impact or the like, the lower layer fine particles 40a are exposed to the outermost surface 40b. Therefore, a defect portion does not occur in the fine particle layer 40, and the state where the surface of the base material portion 36 is covered with the fine particle layer 40 is maintained.

  Further, the dust filter 32 has a conductive layer 42 formed between the base material portion 36 and the fine particle layer 40. The conductive layer 42 is made of a material that has conductivity and transmits photographing light. For example, the conductive layer 42 is made of a transparent conductive material such as ITO (indium tin oxide) or ZnO. Since the conductive layer 42 is formed in the lower layer of the fine particle layer 40, the surface resistance of the outermost surface 40b of the fine particle layer 40 is reduced, so that charging of the outermost surface 40b can be prevented. The conductive layer 42 preferably does not contain the fine particles 40a from the viewpoint of effectively preventing the charging of the outermost surface 40b.

  The dust-proof filter 32 shown in FIG. 2 has the fine particle layer 40 and the conductive layer 42 as described above, so that dust adheres to the surface of the dust-proof filter 32 on the negative side of the X-axis as described below. Can be effectively prevented. Here, the adhesion force that acts when dust floating around the dust filter 32 adheres to the dust filter 32 is mainly composed of three types of forces: liquid bridge force, intermolecular force, and electrostatic force.

  About the liquid bridge | crosslinking force which acts between the outermost surface 40b of the fine particle layer 40 and dust, fine unevenness | corrugations like the surface comprised by the base material part 36 are carried out by the fine unevenness | corrugation formed in the outermost surface 40b, for example. Not as weak as the surface. This is because the contact area between the outermost surface 40b and dust is reduced by the fine irregularities, and accordingly, the liquid cross-linking force for cross-linking the contact surfaces is weakened as a whole.

  Further, by making the fine particles 40a constituting the fine particle layer 40 into a substantially spherical shape as shown in FIG. 2, the contact area between the outermost surface 40b and dust is further reduced, and the liquid bridging force acting between them is increased. It can be further reduced. The fine particles 40a may contain at least one of silicon and fluorine. When the fine particles 40a contain these elements having water repellency, the contact angle between the moisture contained in the dust and the fine particles 40a is increased, so that the liquid bridging force acting between the outermost surface 40b and the dust can be further weakened. .

  As for the intermolecular force acting between the outermost surface 40b of the fine particle layer 40 and the dust, the fine irregularities formed on the outermost surface 40b have fine irregularities such as the surface constituted by the base material portion 36, for example. Not as weak as the surface. As the contact area between the outermost surface 40b and the dust decreases, the distance between the molecules constituting the fine particle layer 40 or the dust also increases, and the intermolecular force acting on the fine particle layer 40 and the dust is weakened as a whole. is there.

  The electrostatic force acting between the outermost surface 40 b of the fine particle layer 40 and dust is weakened by the conductive layer 42 formed under the fine particle layer 40. The conductive layer 42 lowers the surface resistance of the outermost surface 40b of the thin fine particle layer 40, which is the upper layer of the conductive layer 42, efficiently releases the static charge generated on the outermost surface 40b, and charges the outermost surface 40b. This is because it is prevented.

  As described above, the dustproof filter 32 having the fine particle layer 40 and the conductive layer 42 can weaken all of the liquid bridging force, intermolecular force, and electrostatic force that act when dust adheres to the dustproof filter 32. Therefore, the dustproof filter 32 according to the present embodiment can extremely effectively prevent dust from adhering to the outermost surface 40b.

  Further, the dustproof filter 32 according to the present embodiment can increase the reliability of the dust adhesion preventing effect as described above by making the fine particle layer 40 a multilayer structure of the fine particles 40a. For example, when assembling the camera or performing user maintenance, a cleaning operation is performed to remove dust adhering to the dustproof filter 32 by pressing and wiping the cleaning paper containing the cleaning liquid against the outermost surface 40b shown in FIG. May be.

  For this reason, the fine particle layer 40 is required to have a reliability that maintains the effect of preventing the adhesion of dust even when subjected to a physical impact or chemical action generated in a cleaning operation or the like. If the fine particle layer 40 has a multilayer structure, when the fine particles 40a on the outermost surface 40b of the fine particle layer 40 are partially peeled off due to physical impact or the like, the lower fine particles 40a are exposed to the outermost surface 40b.

  Therefore, a defect portion does not occur in the fine particle layer 40, the state where the surface of the base material portion 36 is covered with the fine particle layer 40 is maintained, and the dust adhesion preventing effect of the dust filter 32 is maintained. Further, when the lower layer fine particles 40a are exposed on the outermost surface 40b, the change in the optical performance of the dustproof filter 32 is also suppressed as compared with the case where the conductive layer 42 or the base material portion 36 having a different surface state is exposed. Even when the fine particles 40a are shifted in the thickness direction of the fine particle layer 40 so that the layer thickness of the fine particle layer 40 is larger than the average particle diameter of the fine particles 40a, the same effect as the case where the fine particles 40a are arranged in multiple layers is obtained. be able to.

  By providing the fine particle layer 40 in multiple layers and further providing the conductive layer 42 between the base material portion 36 and the fine particle layer 40, all the forces of dust adhering to the surface are weakened (liquid crosslinking force and intermolecular force are fine particles). The electrostatic force is weakened by the presence of the conductive layer 42 and the surface of the dustproof filter 32 has mechanical strength that can be wiped off and cleaned (the fine particle layer 40 is a multilayer and the conductive layer 42 is a base material portion). 36 and the fine particle layer 40), and the dustproof filter 32 having very high practicality can be realized.

  Although the manufacturing method of the dustproof filter 32 as shown in FIG. 2 is not specifically limited, For example, it can produce with the manufacturing method shown below. First, a conductive layer 42 made of a conductive material such as ITO as a raw material is formed on one surface of the base material portion 36. A method for forming the conductive layer 42 is not particularly limited, and a sputtering method, a vapor deposition method, a laser deposition method, an ion plating method, a spray method, a dipping method, a CVD method, or the like can be used.

After forming the conductive layer 42, the fine particles 40 a made of a material that transmits visible light, such as SiO ₂ or MgF _2, are collected in layers on the conductive layer 42 to form the fine particle layer 40. A method for forming the fine particle layer 40 is not particularly limited, and for example, a Langmuir-Blodgett method (LB method), a printing method, a laser deposition method, or the like can be used.

In the fine particle layer 40 having a structure in which the fine particles 40a are gathered in a multilayer shape, a single fine particle layer is formed a plurality of times on the surface of the base material portion 36 on which the conductive layer 42 is formed using, for example, the Langmuir-Blodgett method. Can be produced.
Second and third embodiments

  3 and 4 are enlarged views of main parts of the dustproof filter 32 provided in the imaging units according to the second and third embodiments. The parts other than the dust filter 32 are the same as those in the first embodiment shown in FIG.

  The dust filter 32 according to the second embodiment shown in FIG. 3 includes an adhesive layer 44 in addition to the base material portion 36, the conductive layer 42, and the fine particle layer 40. The adhesive layer 44 is formed on the surface of the conductive layer 42 on the fine particle layer 40 side, and the fine particles 40 a are fixed to the conductive layer 42.

  A method for forming the adhesive layer 44 is not particularly limited, and a film containing a compound containing an alkyl group such as tetraethoxysilane (TEOS [Si (OC2H5) 4)]) is formed on the surface of the conductive layer 42. Can be formed. In the dustproof filter 32 according to the second embodiment, the conductive layer 42 is formed on the surface of the base material portion 36, the adhesive layer 44 is formed on the surface of the conductive layer 42, and the fine particles 40 a are formed in layers on the surface of the adhesive layer 44. The fine particle layer 40 is formed. Since the adhesive layer 44 more firmly fixes the fine particle layer 40 and the conductive layer 42, the dustproof filter 32 shown in FIG. 3 has high mechanical strength in the vicinity of the outermost surface 40b, and even when subjected to a physical impact or the like. The fine particles 40a are difficult to peel off.

  The dustproof filter 32 shown in FIG. 4 has a mixed layer 46 in which the fine particles 40 a of the fine particle layer 40 are embedded in the adhesive layer 44. However, the fine particles 40a are exposed on the outermost surface 40b of the mixed layer 46, and fine irregularities are formed along the surface shape of the individual fine particles 40a.

  A method for forming the mixed layer 46 is not particularly limited, and for example, a sol-gel method or the like can be used. In the sol-gel method, for example, a material liquid is prepared in which fine colloidal silica and tetraethoxysilane are uniformly dispersed in a predetermined solvent. The prepared material liquid is spin-coated on the surface of the conductive layer 42 or the adhesive layer 44, or is applied by dipping or the like, and a predetermined heat treatment is performed to form the mixed layer 46.

By the heat treatment performed during the formation of the mixed layer 46, tetraethoxysilane is hydrolyzed and a continuous film of SiO2 is formed around the fine particles 40a, so that the continuous film firmly fixes the fine particles 40a. Therefore, the dustproof filter 32 provided in the imaging unit according to the third embodiment has the fine particle layer 40 with high mechanical strength, and even when the dustproof filter 32 is subjected to physical impact or chemical action, The effect of preventing dust adhesion can be maintained. Thus, the dustproof filter 32 provided in the imaging units according to the third and fourth embodiments is excellent in durability and reliability in addition to the effects of the dustproof filter 32 described in the first embodiment. It has the effect.
Fourth embodiment

  FIG. 5 is a schematic cross-sectional view of a digital single-lens reflex camera provided with an imaging unit according to the fourth embodiment, and shows a side cross-section of the camera body 4. In the imaging unit 30 according to the fourth embodiment, the dustproof filter 32 is disposed with respect to the imaging element 38 and the optical low-pass filter 37 with a sealed space interposed therebetween. The digital single lens reflex camera shown in FIG. 5 is the same as the digital single lens reflex camera shown in FIG.

  In addition, the base portion 36 of the dust filter 32 according to the fourth embodiment is a cover member for preventing dust from entering the sealed space in which the optical low-pass filter 37 and the image sensor 38 are disposed. The cover member is formed of a material that transmits visible light, such as glass or resin. The shape of the fine particle layer 40 and the conductive layer 42 formed on the surface on the X negative direction side of the dustproof filter 32 and the method of forming these layers are the same as in the first embodiment.

In the imaging unit 30 according to the fourth embodiment, the optical low-pass filter 37 and the imaging element 38 are disposed with respect to the dust-proof filter 32 with a sealed space interposed therebetween. Therefore, the image pickup unit 30 is not only protected from dust by the optical low-pass filter 37 and the image pickup element 38, but also protected from physical impacts, and has high durability. Note that the dustproof filter 32 provided in the imaging unit 30 according to the fourth embodiment can effectively prevent dust from adhering to the surface of the dustproof filter 32 as in the first embodiment.
Fifth embodiment

  FIG. 6 is a schematic cross-sectional view of a digital single-lens reflex camera including the imaging unit 30 according to the fifth embodiment, and shows a side cross-section of the camera body 4. The imaging unit 30 according to the fifth embodiment has the dust capturing member 48 and the imaging according to the first embodiment except that the wiring 50 is connected to the conductive layer 42 of the dust filter 32. Same as unit.

  As shown in FIG. 6, the conductive layer 42 of the dust filter 32 is electrically connected to the housing 6 of the camera body 4 via the wiring 50. Since the conductive layer 42 of the dustproof filter 32 is kept at the same potential as the housing 6, the dustproof filter 32 shown in FIG. 6 can more effectively prevent the outermost surface of the particulate layer 40 from being charged. Thus, in addition to the effect which the dustproof filter 32 demonstrated in 1st Embodiment has in the dustproof filter 32 with which the imaging unit 30 which concerns on 5th Embodiment was equipped, the adhesion of the dust which an electrostatic force acts on is further effective. Has the effect of preventing.

Further, as shown in FIG. 6, the dust capturing member 48 is arranged so as to surround the periphery of the dustproof filter 32. The dust trapping member 48 has, for example, an adhesive tape, and the dust floating in the space near the dustproof filter 32 can be captured by the adhesive surface of the adhesive tape. As described above, in the fifth embodiment, dust that approaches the dustproof filter 32 can be reduced by the dust trapping member 48, so that dust can be more effectively prevented from adhering to the dustproof filter 32. The dust capturing member 48 is not limited to one having an adhesive tape, and may be one having a dust collection filter or one that captures dust by electrostatic force.
Other embodiments

  In the above-described embodiment, the description has been made using the imaging unit 30 provided in the digital single-lens reflex camera. It may be provided. In addition, the base material portion 36 on which the conductive layer 42 and the fine particle layer 40 are formed on the surface is not limited to the optical low-pass filter or the cover member, but may be an infrared cut filter or other optical components.

FIG. 1 is a schematic cross-sectional view of a digital single-lens reflex camera including an imaging apparatus according to first to third embodiments of the present invention. FIG. 2 is an enlarged view of a main part of the dustproof filter provided in the imaging apparatus according to the first embodiment of the present invention. FIG. 3 is an enlarged view of a main part of the dustproof filter provided in the imaging apparatus according to the second embodiment of the present invention. FIG. 4 is an enlarged view of a main part of the dustproof filter provided in the imaging apparatus according to the third embodiment of the present invention. FIG. 5 is a schematic cross-sectional view of a digital single-lens reflex camera including an imaging apparatus according to the fourth embodiment of the present invention. FIG. 6 is a schematic cross-sectional view of a digital single-lens reflex camera including an imaging apparatus according to the fifth embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 6 ... Case 30 ... Imaging unit 32 ... Dust-proof filter 36 ... Base material part 38 ... Imaging element 40 ... Fine particle layer 40a ... Fine particle 40b ... Outermost surface 42 ... Conductive layer 44 ... Adhesive layer 46 ... Mixed layer

Claims (11)

An imaging unit for imaging an image by an optical system;
A base material that is provided opposite to the imaging unit and has optical transparency;
Of the surface of the base material, a particle layer including a plurality of particles provided on the surface opposite to the side where the imaging unit is disposed;
An imaging apparatus comprising: a conductive layer provided between the base material and the particle layer. The imaging apparatus according to claim 1,
The image pickup apparatus, wherein the particles have water repellency. The imaging apparatus according to claim 1 or 2,
The image pickup apparatus, wherein the particle layer has a structure in which the particles are gathered in a multilayer shape. The imaging apparatus according to any one of claims 1 to 3, wherein
An image pickup apparatus, wherein an adhesive layer for fixing the particles to the conductive layer is formed on a surface of the conductive layer on the particle layer side. The imaging apparatus according to any one of claims 1 to 4, wherein:
The imaging device, wherein the conductive layer does not include the particles. An imaging apparatus according to any one of claims 1 to 5, wherein
The imaging apparatus according to claim 1, wherein a thickness of the particle layer is larger than an average particle diameter of the particles. The imaging apparatus according to any one of claims 1 to 6,
The average particle size of the particles is 5 nm to 200 nm. The imaging apparatus according to any one of claims 1 to 7,
The imaging device, wherein the particles include at least one of silicon and fluorine.   A camera comprising the imaging device according to claim 1.   A method for manufacturing an imaging device, comprising: forming a conductive layer having conductivity on a base material that transmits light; and forming particles in layers on the conductive layer. The manufacturing method according to claim 10, comprising:
A method of manufacturing an imaging device, wherein the step of forming particles in a layered form on the conductive layer is performed a plurality of times.

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