JP2013013017A - Imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent dust attached to a dustproof glass disposed on the front side of an imaging device from being included in a taken image and to prevent occurrence of stray light entering the imaging device.SOLUTION: An imaging apparatus is provided with: a sensor unit 14 comprising an imaging device 14a for taking an image of a subject light from a subject; and a structure 20 provided with a dustproof optical member 22 disposed on the subject side of the sensor unit and forming a sealed space inside in cooperation with the dustproof optical member. In the structure, a distance between the light-receiving surface of the imaging device and the dustproof optical member is set to be a predetermined distance and a diaphragm member 28 is provided at a position adjacent to the dustproof optical member within the sealed space.

Description

  The present invention relates to an imaging apparatus.

  An imaging device such as an interchangeable lens digital camera has a structure in which the internal space of the camera body is exposed to the outside when the photographic (exchange) lens is attached or detached. There is a problem of adhering to the imaging unit. For this reason, there is an electronic camera device in which a transparent cover is disposed on the front surface of the mirror box structural member in which the quick return mirror is accommodated, and dust is prevented from adhering to the image pickup device by using the inside of the mirror box structural member as a sealed space ( For example, see Patent Document 1).

JP 2000-241869 A

  However, in the above-described electronic camera device, the stray light generated when the subject light incident inside the mirror box structure member through the transparent cover is reflected by the bottom surface of the mirror box structure member and the like is incident on the image sensor and is photographed. In some cases, a ghost occurred.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an imaging device that prevents dust adhering to dust-proof glass disposed on the front side of an imaging device from appearing in a captured image and prevents stray light from entering the imaging device. It is to be.

  The present invention solves the above problems by the following means. In addition, in order to make an understanding easy, it attaches | subjects and demonstrates the code | symbol corresponding to embodiment of this invention, but this invention is not limited to this.

  The imaging apparatus of the present invention includes a sensor unit (14) having an imaging element (14a) that captures an image of subject light from a subject, and a dust-proof optical member (22) disposed closer to the subject than the sensor unit. A structure (20) that forms a sealed space in cooperation with the dust-proof optical member, and the structure is a distance between the light-receiving surface of the image sensor and the dust-proof optical member. Is set to a predetermined distance, and a diaphragm member (28) is provided at a position close to the dustproof optical member in the sealed space.

  ADVANTAGE OF THE INVENTION According to this invention, while adhering to the dust-proof glass arrange | positioned at the front side of an image pick-up element, it can prevent appearing in the image | photographed image, and generation | occurrence | production of the stray light which injects into an image pick-up element can be prevented.

It is sectional drawing which shows the internal structure of the camera which concerns on embodiment. It is a figure which shows the state which prevents generation | occurrence | production of a stray light with the aperture_diaphragm | restriction member which concerns on embodiment. It is a figure which shows the structure of the pressing member of the dustproof glass which concerns on embodiment. It is a figure which shows the state which has generated the stray light when not providing the aperture_diaphragm | restriction member which concerns on this Embodiment.

  Hereinafter, a digital camera (hereinafter referred to as a camera) according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing the internal configuration of the camera according to the embodiment. 1 shows a state in which the interchangeable lens 40 (see FIG. 2) is removed from the camera body 10 of the camera 1. Further, in FIG. 1, the illustration of the outer cover of the camera body 10 is omitted. In the following, since the subject exists on the left side in FIGS. 1 and 2, the left side in the drawing may be referred to as the subject side or the front side in the optical axis X direction. In addition, the right side in the drawing may be referred to as the camera back side (back side) in the optical axis X direction.

  The camera body 10 includes a body mount 10M, and the interchangeable lens 40 is attached to the camera body 10 by coupling a lens mount provided on the interchangeable lens 40 to the body mount 10M. Therefore, various interchangeable lenses 40 having a focal length and a function corresponding to the subject to be photographed can be attached to the camera body 10.

  A sensor unit 14 is held on the front side of the imaging substrate 12 disposed on the back side of the camera body 10. The sensor unit 14 includes an image sensor 14a configured by a CCD or a CMOS that converts subject light into an electrical signal, and a cover glass 14b that is disposed on the front side of the image sensor 14a. A dust-proof rubber member 16 is disposed at the peripheral portion on the front side of the sensor unit 14, and a low-pass filter 18 is disposed on the front side of the sensor unit 14 a via the rubber member 16. Here, the low-pass filter 18 is a filter for suppressing the occurrence of moire or the like in the subject image formed on the light receiving surface of the image sensor 14a.

  On the front side of the low-pass filter 18, a rectangular tube-shaped light shielding structure 20 is disposed. A dust-proof rubber member 16 is disposed between the back side of the light shielding structure 20 and the front side of the cover glass 14b of the sensor unit 14, and the back side of the light shielding structure 20 and the cover glass 14b of the sensor unit 14 are provided. Are in close contact. A dust-proof glass 22 is disposed on the front side of the light shielding structure 20 as a dust-proof optical member. Here, an antistatic film is formed on the front surface of the dust-proof glass 22, and an antireflection film is formed on the rear surface.

  Between the back side of the dust-proof glass 22 and the front side of the light shielding structure 20, a dust-proof rubber member 24 provided at the peripheral edge on the front side of the light shielding structure 20 is disposed. The dustproof glass 22 is fixed to the front side of the light shielding structure 20 by a pressing member 26. Thereby, the back side of the dust-proof glass 22 and the front side of the light shielding structure 20 are adhered.

  Accordingly, a dust-proof rubber member 24 is disposed between the front side of the light shielding structure 20 and the dust-proof glass 22, and the dust-proof rubber is provided between the rear side of the light-shielding structure 20 and the cover glass 14 b of the sensor unit 14. Since the member 16 is disposed, the inside of the light shielding structure 20 can be a sealed space. Accordingly, it is possible to prevent dust from entering the sealed space.

  The light shielding structure 20 has a length in the optical axis direction in which the distance in the optical axis direction between the light receiving surface of the image sensor 14a and the front surface of the dust-proof glass 22 is a predetermined distance, and the inner wall surface 20a is subjected to a textured process. It has been subjected. Here, the predetermined distance is a distance at which a dust image is not formed on the light receiving surface of the image sensor 14a when dust having a diameter of less than 0.1 mm adheres to the surface of the dust-proof glass 22, that is, the contrast becomes extremely low. The distance is obtained from the pixel pitch of the image sensor 14a (for example, less than 7%).

  The light shielding structure 20 includes a diaphragm member 28 at a position close to the dust-proof glass 22 in the sealed space in the light shielding structure 20. The diaphragm member 28 is made of black resin, and an edge portion 28a that forms a rectangular opening is an inclined surface that is inclined toward the inner wall surface 20a side of the light shielding structure 20 on the imaging element 14a side of the diaphragm member 28. Have

  The body mount 10M is fixed to the front side of the camera structure 34 with a mount screw 36. On the back side of the body mount 10M, that is, on the dust-proof glass 22 side, an aperture portion 30 that blocks harmful light is formed. Further, the imaging substrate 12 is fixed to the back side of the camera structure 34 with a mount screw 36.

  In the camera 1 according to this embodiment, as shown in FIG. 2, the subject light R is blocked by the diaphragm member 28 via the interchangeable lens 40 and enters the inner wall surface 20a of the light shielding structure 20. Generation of stray light caused by reflection at the inner wall surface 20a can be prevented. Further, since the edge portion 28a on the imaging element 14a side of the diaphragm member 28 has an inclined surface inclined toward the inner wall surface 20a side of the light shielding structure 20, the subject light is reflected by this inclined surface and becomes stray light. Can be prevented. Furthermore, since the antireflection film is formed on the surface on the back side of the dustproof glass 22, stray light can be prevented from being generated from the surface on the backside of the dustproof glass 22.

  Here, for comparison with the present embodiment, the subject light R when the diaphragm member 28 is not provided will be described. FIG. 4 differs from FIG. 2 only in that the diaphragm member 28 is not provided. In FIG. 4, the subject light R is reflected by the inner wall surface 20a of the light shielding structure 20, and enters the image pickup surface of the image pickup device 14a as shown. That is, the subject light R becomes stray light and enters the image sensor 14a, which causes a ghost in the image. If the interval (length) between the inner wall surfaces 20a of the light shielding structure 20 is sufficiently short, such stray light is unlikely to occur. However, in order to prevent the image pickup element from picking up an image of foreign matters such as dust adhering to the dustproof glass 22 (so as to blur the image), the image pickup surface of the image pickup element 14a and the dustproof glass 22 in the optical axis direction. It is necessary to secure a certain interval. In other words, securing this distance means increasing the length of the inner wall surface 20a of the light shielding structure 20 in the optical axis direction.

  As described with reference to FIG. 4 above, when the dust-proof glass 22 shown in the present embodiment is configured in the camera body 10, it is necessary to secure a certain length of the inner wall surface 20a in the optical axis direction. If this embodiment (the diaphragm member 28 shown in FIGS. 1 and 2) is employed, even if a foreign object adheres to the dust-proof glass 22, it is possible to suppress the reflection of the image and to generate a ghost due to stray light. Can also be suppressed.

  Further, according to this embodiment, a sealed space isolated from the outside is formed between the dust-proof glass 22 and the sensor unit 14. As a result, dust can be prevented from entering the sealed space. Therefore, when the interchangeable lens 40 is replaced, dust that has entered from the outside adheres to the sensor unit 14 (the light receiving surface of the image sensor 14a or the low-pass filter 18). In addition, it is possible to prevent a problem that a dust image is formed on the light receiving surface of the image sensor 14a. When the interchangeable lens 40 is replaced, if dust adheres to the outer surface (front surface) of the dust-proof glass 22, it can be easily seen if it has a diameter of 0.1 mm or more. It can be easily removed. Further, if the diameter is less than 0.1 mm, the dust-proof glass 22 is disposed at a distance where the image of the dust is not formed on the light receiving surface of the image sensor 14a, so that it can be prevented from appearing in the image. .

  In the above-described embodiment, the dust-proof glass 22 is fixed to the light-shielding structure 20 by the pressing member 26. However, as shown in FIG. 3A, the dust-proof glass-side pressing portion 26a of the pressing member 26 and A predetermined gap x (for example, a gap of 0.1 mm) may be formed between the surface of the dust-proof glass 22. In this case, when the user wipes off dust (dust having a diameter of 0.1 mm or more) adhering to the surface of the dust-proof glass 22, the subject of the dust-proof glass 22 is pushed and held in the gap. Dust in a region where light passes can be removed.

  Further, as shown in FIG. 3B, a predetermined gap is formed between the dust-proof glass side pressing portion 26a of the pressing member 26 and the surface of the dust-proof glass 22, and a region facing the dust-proof glass side pressing portion 26a is formed. An adhesive member 42 such as a double-sided tape may be disposed on the surface of the dustproof glass 22. In this case, when the user wipes off the dust adhering to the surface of the dust-proof glass 22, when the dust that has not been wiped is pushed into the gap, the dust adheres to the adhesive member 42, and the dust is again applied to the subject light of the dust-proof glass 22. It is possible to prevent adhesion to a passing region.

DESCRIPTION OF SYMBOLS 1 ... Camera, 10 ... Camera body, 10M ... Body mount, 12 ... Imaging board, 14 ... Sensor unit, 14a ... Imaging element, 16 ... Rubber member, 18 ... Low pass filter, 20 ... Light shielding structure, 20a ... Inner wall surface, 22 ... dustproof glass, 24 ... rubber member, 26 ... pressing member, 28 ... squeezing member, 42 ... adhesive member

Claims (7)

A sensor unit having an image sensor that captures an image of subject light from the subject;
A structure that includes a dust-proof optical member disposed closer to the subject than the sensor unit, and that forms a sealed space inside in cooperation with the dust-proof optical member;
Have
The structure has a predetermined distance between the light receiving surface of the image sensor and the dustproof optical member, and includes a diaphragm member at a position close to the dustproof optical member in the sealed space. An imaging device.   The imaging device according to claim 1, wherein an edge portion forming the opening of the diaphragm member has an inclined surface inclined toward the inner wall surface side of the structure on the imaging element side of the diaphragm member.   The imaging apparatus according to claim 1, wherein the diaphragm member is made of a black resin.   The imaging device according to any one of claims 1 to 3, wherein the structure has a cylindrical shape having a predetermined length, and an inner wall surface is textured. .   The predetermined distance is a distance at which an image of an object of a predetermined size attached to the surface of the dust-proof optical member is not formed on the light receiving surface of the image sensor. The imaging device according to any one of the above. The dust-proof optical member is fixed to the front side of the structure by a pressing member,
The predetermined clearance gap is formed between the said dust-proof optical member side pressing part of the said pressing member, and the surface of the said dust-proof optical member, The Claim 1 characterized by the above-mentioned. Imaging device.   The imaging apparatus according to claim 6, wherein an adhesive member is disposed on a surface of the dust-proof optical member facing the dust-proof optical member-side pressing portion.

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