JP5439966B2 - Imaging device - Google Patents

Description

  The present invention relates to an imaging apparatus that captures a subject image.

Conventionally, for example, in an interchangeable lens camera, in order to prevent dust from adhering to the image sensor at the time of lens replacement, the image sensor is disposed in a sealed space. However, since the image sensor generates heat, the temperature in the sealed space rises. When the temperature in the sealed space rises, a temperature difference from the outside occurs during lens replacement, and condensation may occur on the glass member that is a wall portion that forms the sealed space and is disposed in the photographing optical path.
On the other hand, there is a device that prevents the generation of dew condensation inside by holding a heat-generating optoelectronic component in a sealed space and providing a temperature control unit in the sealed space to keep the temperature constant (for example, Patent Documents). 1).

JP-A-5-243588

  However, in the interchangeable lens camera, the photographing lens may be replaced in a low temperature environment. In this case, even if the temperature control unit is provided in the sealed space as in the above-described prior art, there is a possibility that the temperature difference between the inside and outside is too large and the glass member is cooled to cause dew condensation.

  An object of the present invention is to provide an imaging device in which the occurrence of dew condensation is prevented in a translucent member disposed in a photographing optical path.

The present invention solves the above problems by the following means .

According to one aspect of the present invention, an imaging equipment for capturing lens is detachably mounted, for holding the image pickup element that captures a subject image by receiving the object light via the imaging lens an imaging holding unit, the imaging holder or al, a first side wall extending on the object side in the optical axis direction of the imaging lens is disposed on the object side of the first side wall portion, received by the imaging element is said subject light can transmit to be a first cover which together form a closed space and the imaging holder及 beauty the first side wall, the object light received on the imaging element is a permeable Te, the sealed space, the a between the first closed empty first cover side, a second cover that an image pickup holding portion separated on the between the first closed spatial by Ri large second closed air When, wherein the imaging device is provided with a mount portion for mounting the imaging lens, before The mount portion extends from the imaging holding portion and is disposed on the subject side of a second side wall portion different from the first side wall portion, the first cover is fixed to the second side wall portion, and the second cover is It can move relative to the first cover in the optical axis direction, and a portion of the first side wall portion between the first cover and the second cover is formed by an elastic member. This is an imaging device characterized by the above .

  ADVANTAGE OF THE INVENTION According to this invention, the imaging device by which generation | occurrence | production of the dew condensation in the translucent member arrange | positioned at the imaging | photography optical path was prevented can be provided.

It is a longitudinal cross-sectional view of the camera of the state which mounted | wore with the lens-barrel in 1st Embodiment of this invention. It is sectional drawing of the imaging box in 2nd Embodiment of this invention. It is sectional drawing of the imaging box in 3rd Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings. Each figure shown below is provided with an XYZ orthogonal coordinate system for ease of explanation and understanding. In this coordinate system, when the photographer shoots a horizontally long image with the optical axis OA being horizontal, the direction toward the left as viewed from the photographer at the position of the camera (hereinafter referred to as the positive position) is the X plus direction and the positive position. The direction toward the upper side is the Y plus direction, and the direction toward the subject at the normal position is the Z plus direction.

(First embodiment)
FIG. 1 is a longitudinal sectional view of the camera 1 in a state in which the lens barrel 20 according to the first embodiment of the present invention is mounted. The camera 1 is an interchangeable lens camera, and includes a camera body 10 and a lens barrel 20 that can be attached to and detached from the camera body 10.
The lens barrel 20 includes a photographing lens 21 constituting an imaging optical system therein.

  The camera body 10 includes a camera side mount 10M, and the lens barrel 20 includes a lens side mount 20M. The lens barrel 20 is attached to the camera body 10 with the optical axis A aligned by the coupling of the camera side mount 10M and the lens side mount 20M. Thus, since the lens barrel 20 can be attached to and detached from the camera body 10, different types of lens barrels having different focal lengths and functions can be exchanged depending on the object to be photographed.

The camera body 10 includes a camera housing 11 and an imaging box 30 provided therein.
An opening 12 through which subject light from the lens barrel 20 passes is formed at a substantially central portion on the front side (Z plus side) of the camera housing 11. The camera-side mount 10M is provided on the front side of the opening 12 in the camera housing 11. The imaging box 30 is fixed inside the opening 12 in the camera housing 11.

  Inside the imaging box 30, a sensor unit 40 including an imaging element 41 such as a CCD that converts subject light into an electrical signal is disposed. The details of the imaging box 30 will be described later.

The sensor unit 40 includes an image sensor 41, a package 42, a cover glass 43, a low-pass filter 44, and an electronic mounting board 45.
The imaging element 41 is a photoelectric conversion element such as a CCD that converts subject light into an electrical signal.
The package 42 is a member that accommodates and holds the image sensor 41.
The cover glass 43 is provided on the front side of the package 42 so as to cover the image sensor 41.
The low-pass filter 44 is disposed on the front side of the package 42 and suppresses the occurrence of moire in the subject image formed on the light receiving surface of the image sensor 41.
The electronic mounting board 45 is provided around the back side of the package 42 and performs electrical connection between the package 42 and the outside.
Each component of the sensor unit 40 is supported by a support substrate 46 constituting the imaging box 30 via a package 42.

  An electronic viewfinder 50 is disposed on the upper surface side (Y plus side) of the camera housing 11. A display device 60 made of a liquid crystal panel is provided on the back side (Z minus side) of the camera housing 11.

  The electronic viewfinder 50 includes an imaging irradiation module 51 and an eyepiece optical system 52. The electronic viewfinder 50 displays the through image captured by the image sensor 41 on the imaging irradiation module 51. The photographer can visually recognize the image displayed on the imaging irradiation module 51 through the eyepiece optical system 52. Thereby, even if it is the structure which is not equipped with a quick return mirror, the imaging by the image pick-up element 41 can be seen in real time like what is called a single-lens reflex camera.

  The display device 60 includes a liquid crystal panel that displays a through image captured by the image sensor 41. In addition, the display device 60 has a function setting menu for setting various functions in the camera 1, setting information and photometric information related to photographing input by the user via the operation unit, such as shutter speed, aperture, and exposure correction information. Etc. are displayed. Further, the photographed image, its histogram, photographing information and the like are displayed.

  In the camera 1 having the above-described configuration, the subject image formed on the image sensor 41 in the imaging box 30 via the optical system (the photographing lens 21) of the lens barrel 20 is converted into an electric signal by the image sensor 41. The imaging data photoelectrically converted by the imaging element 41 is signal-processed as image data by a control unit (not shown) included in the camera 1. The signal-processed image data is sent to the electronic viewfinder 50 and the display device 60, and is recorded in a recording device (not shown) at the time of photographing.

  Note that the camera 1 of the present embodiment does not include a mechanical shutter device. The control unit adjusts the exposure time of the subject light with respect to the image sensor 41 at the time of shooting (the time during which the image sensor 41 accumulates the subject light) by electrically controlling the image sensor 41 (electronic shutter control).

Next, the imaging box 30 will be described in detail.
The imaging box 30 includes a side wall 31 that extends from the support substrate 46 that holds the sensor unit 40 described above.
The side wall portion 31 is airtightly fixed to the outer peripheral portion of the support substrate 46 by screws 39. The side wall portion 31 has a cylindrical shape with a rectangular cross section that opens front and rear, and an opening portion 31 </ b> A having a shape similar to the opening portion 12 in the camera housing 11 is formed on the front side.

A protective cover 32 is disposed on the inner side (back side) of the opening 31 </ b> A in the side wall portion 31.
The protective cover 32 is formed with a predetermined thickness from a transparent material such as glass or transparent resin. The both surfaces of the protective cover 32 on the incident / exit side are coated with an antireflection coating. The protective cover 32 is airtightly fixed to the inner surface of the inner edge portion that forms the opening 31 </ b> A in the side wall portion 31.
In this way, by ensuring the airtightness between the support substrate 46 and the side wall portion 31 and ensuring the airtightness between the side wall portion 31 and the protective cover 32, the airtight state inside the imaging box 30 is maintained. .

On the back side of the protective cover 32 in the side wall portion 31, a dew condensation prevention cover 33 is disposed at a position spaced apart from the protective cover 32 by a predetermined distance.
Similar to the protective cover 32, the condensation prevention cover 33 is formed with a predetermined thickness from a transparent material such as glass or transparent resin, and is airtightly fixed to the inner surface of the side wall portion 31. Anti-reflective coating is applied on both the entrance and exit sides of the condensation prevention cover 33.

  With the above-described configuration, an airtight space (front airtight space 35) that is isolated from the outside by the dew condensation prevention cover 33 and the front protective cover 32 is formed inside the side wall portion 31. Further, an airtight space (rear airtight space 36) isolated from the outside is formed by the dew condensation prevention cover 33 and the sensor unit 40 (support substrate 46) located on the back side thereof. Here, the arrangement position of the dew condensation prevention cover 33 inside the side wall portion 31 is set closer to the protective cover 32 than the sensor unit 40, and therefore the volume of the front airtight space 35 is smaller than the rear airtight space 36. Since the protective cover 32 and the dew condensation prevention cover 33 are formed of a transparent material as described above, they do not hinder the transmission of subject light.

As described above, this embodiment has the following effects.
(1) As described above, according to the present embodiment, the front airtight space 35 is formed between the protective cover 32 and the condensation prevention cover 33, and the rear airtight space 36 is formed between the condensation prevention cover 33 and the sensor unit 40. Has been. Thereby, it is possible to prevent dust and the like from entering the inside of the imaging box 30 from the outside, and it is possible to avoid problems such as dust that has entered the sensor unit 40 being attached to the sensor unit 40 and appearing in the imaging.
(2) Further, since the front airtight space 35 is provided on the front side of the rear airtight space 36 in which the sensor unit 40 is accommodated, dew condensation does not occur on the inner surface of the protective cover 32. That is, the air inside the rear airtight space 36 is heated by the heat generated by the image sensor 41 and the like. On the other hand, the outer surface of the protective cover 32 is exposed to the outside when the lens barrel 20 is replaced. For this reason, in the configuration in which the space for housing the sensor unit 40 is sealed with the single protective cover 32 interposed therebetween, there is a possibility that condensation occurs on the inner surface when the protective cover 32 is cooled by external cold air or the like. The configuration can prevent such condensation from occurring. Therefore, according to the camera 1, even if the lens barrel 20 is replaced in a cold region, for example, condensation does not occur on the inner surface of the protective cover 32, and shooting is not hindered.

(Second Embodiment)
Next, a second embodiment of the present invention will be described.
FIG. 2 is a cross-sectional view of the imaging box 300 in the camera to which the second embodiment of the present invention is applied. The configuration of the camera excluding the imaging box 300 is the same as that of the first embodiment described above, and a description thereof is omitted. Further, in the figure, the same components as those in the first embodiment described above are denoted by the same reference numerals and description thereof is omitted.

An imaging box 300 shown in FIG. 2 has a double structure of an outer wall portion 301 and an inner wall portion 302.
Similar to the side wall 31 in the first embodiment described above, the outer wall 301 has a rectangular tube shape having an opening 301 </ b> A on the front surface side, and a support substrate 46 that holds the sensor unit 40 is predetermined with respect to the camera housing 11. The distance between the mount surface and the imaging surface with high accuracy: L is supported. In this structure, the connection part of the outer wall part 301 and the sensor unit 40 does not need to be airtight.

  The inner wall portion 302 has a rectangular tube shape that is slightly smaller than the outer wall portion 301 in all directions in the X-axis, Y-axis, and Z-axis directions, and is airtightly attached to the front surface side of the support substrate 46 in the sensor unit 40. The inner wall 302 is made of a resin material such as ABS or polycarbonate, for example. A predetermined gap is set between the outer surface of the inner wall portion 302 and the inner surface of the outer wall portion 301 so as to be non-contact. The inner wall portion 302 is configured to be thermally expandable when affected by heat generated by the sensor unit 40 provided in an airtight space 36 described later.

A protective cover 32 is airtightly attached to the opening 302 </ b> A on the front side of the inner wall 302. Further, on the back side of the protective cover 32 in the inner wall portion 302, a dew condensation prevention cover 33 is airtightly disposed at a position spaced apart from the protective cover 32 by a predetermined distance.
With the above configuration, in the imaging box 300, the opening on the front side of the inner wall 302 is hermetically closed by the protective cover 32, and the dew condensation prevention cover 33 is hermetically disposed on the inner side (back side). . As a result, a front airtight space 35 is formed between the protective cover 32 and the dew condensation prevention cover 33, and a rear airtight space 36 is formed between the dew condensation prevention cover 33 and the sensor unit 40 on the back side thereof.

As described above, this embodiment has the following effects.
(1) In the imaging box 300 of this embodiment, it is possible to prevent dust and the like from entering the inside of the inner wall portion 302 from the outside, and the dust and the like that have entered the sensor unit 40 are reflected in the imaging. The trouble can be avoided.
(2) Since the front airtight space 35 is provided on the front side of the rear airtight space 36 in which the sensor unit 40 is accommodated, dew condensation does not occur on the inner surface of the protective cover 32.
(3) It is possible to suppress the occurrence of problems due to the expansion of the imaging box 300 due to the heat generated by the sensor unit 40 (imaging device 41 or the like). That is, since the sensor unit 40 and the mount unit 10M are respectively supported by the camera casing 11 via the outer wall portion 301 (not via the inner wall portion 302), the inner wall portion 302 is caused to be Z-axis by the heat generated by the sensor unit 40 Even if it expands in the direction, the distance L between the mount surface and the imaging surface is not changed. In addition, it is more preferable that the outer wall portion 301 is formed of a material having a smaller thermal expansion coefficient than the inner wall portion 302.

(Third embodiment)
Next, a third embodiment of the present invention will be described.
FIG. 3 is a cross-sectional view of the imaging box 310 in the camera to which the third embodiment of the present invention is applied. The configuration of the camera excluding the imaging box 310 is the same as that of the first embodiment described above, and a description thereof is omitted. Further, in the figure, the same components as those in the first embodiment described above are denoted by the same reference numerals and description thereof is omitted.

An imaging box 310 shown in FIG. 3 has a double structure of an outer wall portion 311 and an inner wall portion 312. The inner wall portion 312 is made of the same material as the inner wall portion 302 described in the second embodiment, and is configured to be thermally expandable as in the second embodiment.
The outer wall portion 311 has a rectangular tube shape like the imaging box 30 in the first embodiment described above, and supports the sensor unit 40 with respect to the camera housing 11 at a predetermined accuracy between a mount surface and an imaging surface distance: L. doing.

  A protective cover 32 is provided on the inner side (rear side) of the opening 311A in the outer wall 311. The protective cover 32 is airtightly fixed to the inner surface of the opening 311A in the outer wall 311. A holding edge 311 </ b> B that holds the protective cover 32 is formed on the back side of the protective cover 32 in the outer wall portion 311.

The inner wall portion 312 has a rectangular tube shape that is slightly smaller than the outer wall portion 311 in all directions in the X-axis, Y-axis, and Z-axis directions, and is airtightly attached to the front surface side of the support substrate 46 in the sensor unit 40. A predetermined gap is set between the outer surface of the inner wall portion 312 and the inner surface of the outer wall portion 311 so that they are not in contact with each other.
A dew condensation prevention cover 33 is airtightly disposed in the opening on the front surface side of the inner wall portion 312. The front side end of the inner wall 312 is set to be separated from the protective cover 32 and the holding edge 311B provided on the front side of the outer wall 311 by a predetermined distance.

An airtight seal 313 is disposed between the edge of the outer wall 311 where the opening 311 </ b> A is provided and the tip of the inner wall 312. The hermetic seal 313 is formed to be extendable and contractible by an elastic material such as rubber, and is provided over the entire circumferential direction.
With the above configuration, the front airtight space 35 is formed between the protective cover 32 provided on the outer wall portion 311 and the dew condensation prevention cover 33 provided on the inner wall portion 312, and between the condensation prevention cover 33 and the sensor unit 40 on the back side thereof. A rear airtight space 36 is formed in the front.

As described above, this embodiment has the following effects.
(1) According to the imaging box 310 of the present embodiment, it is possible to prevent dust and the like from entering the inside of the inner wall 312 from the outside, and the dust and the like that have entered the sensor unit 40 and appear in the imaging. Etc. can be avoided.
(2) Since the front airtight space 35 is provided on the front side of the rear airtight space 36 in which the sensor unit 40 is accommodated, dew condensation does not occur on the inner surface of the protective cover 32.
(3) Even if expansion occurs in the inner wall portion 312 due to heat generated by the sensor unit 40 (image sensor 41 or the like), the airtight seal 313 is elastically deformed, so that the airtight state of the front airtight space 35 is maintained and the outer wall portion 311 Relative displacement with the inner wall portion 312 is allowed. For this reason, deformation stress does not act on the outer wall 311 and the distance L between the mount surface and the imaging surface is not changed.

(Deformation)
The present invention is not limited to the above-described embodiment, and various modifications and changes as described below are possible, and these are also within the scope of the present invention.
(1) In each of the above embodiments, a heating element that does not affect imaging may be provided inside the protective cover 32 (on the front airtight space 35 side) or inside the protective cover 32. Thereby, even if dew condensation occurs on the inner surface of the protective cover 32, it can be easily eliminated. Further, an inert dry gas (such as nitrogen gas) may be sealed in the front airtight space 35.
(2) In the third embodiment, if the outer wall 311 is airtightly attached to the support substrate 46 of the sensor unit 40, the airtight seal 313 is not necessarily provided.
(3) In each of the above embodiments, the internal dew condensation prevention cover 33 disposed on the side wall 31, the inner wall 302, or the inner wall 312 may be configured by a low-pass filter. Thereby, a structure can be simplified.
In addition, although embodiment and a deformation | transformation form can also be used in combination as appropriate, detailed description is abbreviate | omitted. Further, the present invention is not limited to the embodiment described above.

  1: camera, 10: camera body, 10M: camera side mount, 21: photographing lens, 31: side wall, 32: protective cover, 33: condensation prevention cover, 35: front airtight space, 36: rear airtight space, 40: sensor unit, 301: outer wall portion, 302: inner wall portion, 311: outer wall portion, 312: inner wall portion, 313: hermetic seal, OA: optical axis, L: distance between mount surface and imaging surface

Claims (1)

An imaging device in which a photographic lens is detachably mounted,
An imaging holding unit that holds an imaging element that receives subject light via the photographing lens and captures a subject image;
A first side wall portion extending from the imaging holding portion to the subject side in the optical axis direction of the photographing lens;
A first cover that is disposed on the subject side of the first side wall and is capable of transmitting the subject light received by the imaging device and forms a sealed space together with the imaging holding unit and the first side wall;
The subject light received by the image sensor can be transmitted, and the sealed space is divided into a first sealed space on the first cover side and a second larger on the imaging holding unit side than the first sealed space. A second cover that divides into a sealed space ,
The imaging device includes a mount portion for mounting the photographing lens,
The mount portion is disposed on the subject side of a second side wall portion that extends from the imaging holding portion and is different from the first side wall portion,
The one cover is fixed to the second side wall;
The second cover is movable relative to the first cover in the optical axis direction;
Wherein one of the first side wall portion, the portion between the second cover and the first cover is Rukoto is formed by an elastic member,
An imaging apparatus characterized by the above.

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