JP2013019997A - Imaging unit and camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging unit and a camera that suppress internal reflection of image light to provide images in which the occurrence of flare is suppressed.SOLUTION: An imaging unit 40 of the present invention includes a rectangular image pickup device 40S, and a rectangular light-transmissive optical member 43 placed on the front side of the image pickup device 40S. The length of the short side of the light-transmissive optical member 43 is 177% or more and 200% or less of the length in the short side direction of an effective pixel area 40R of the image pickup device 40S.

Description

  The present invention relates to an imaging unit and a camera.

The digital camera obtains image information by converting a subject image formed by an imaging optical system into an electrical signal by an imaging element such as a CCD or a CMOS (takes a digital image).
2. Description of the Related Art Conventionally, not only a digital camera but also an imaging apparatus, when light enters an imaging means (imaging device or the like) from an imaging optical system, ghost and flare are generated due to intense light incident from outside the field of view. For this reason, a member that forms an optical path from the image pickup optical system to the image pickup means and an intervening optical element are configured to prevent internal reflection of image light and suppress the occurrence of flare (see, for example, Patent Document 1). .

JP 2007-65109 A

However, in a digital camera, there are more optical elements intervening in the path from the imaging optical system to the imaging device, compared to a film camera, and the sensitivity of the imaging device is also improved. For this reason, in order to obtain a good image in which the occurrence of flare is suppressed, a configuration in which internal reflection of image light is more precisely suppressed is necessary.
The subject of this invention is providing the imaging unit and camera which can obtain the image which suppressed internal reflection of image light and suppressed generation | occurrence | production of flare.

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

The invention according to claim 1 includes a rectangular imaging element (40S) and a rectangular light transmitting optical member (43) positioned on the front side of the imaging element (40S), and the light transmitting optical member ( 43) The length of the short side of the image pickup device (40S) is 177% or more and 200% or less of the length in the short side direction of the effective pixel region (40R) of the image pickup device (40S). It is.
The invention according to claim 2 is the imaging unit (40) according to claim 1, wherein a length of a long side of the light transmitting optical member (43) is the effective pixel of the imaging element (40S). The imaging unit (40) is characterized by being 148% or more of the length in the long side direction of the region (40R).
The invention according to claim 3 is the imaging unit (40) according to claim 1 or 2, wherein the area of the light transmitting optical member (43) is the effective pixel region (40S) of the imaging element (40S). The image pickup unit (40) is characterized by being 262% or more of the area of 40R).
Invention of Claim 4 is an imaging unit (40) of any one of Claim 1 to 3, Comprising: The length of the short side of the said light transmissive optical member (43) is the said image pick-up element. The imaging unit (40) is characterized by being 188% or more and 250% or less of the length in the short side direction of the effective pixel region (40R) of (40S).
Invention of Claim 5 is an imaging unit (40) of any one of Claim 1 to 4, Comprising: The said light transmission optical member (43) is an optical low-pass filter, It is characterized by the above-mentioned. The imaging unit (40).
Invention of Claim 6 is an imaging unit (40) of any one of Claim 1-5, Comprising: The surface of the said image pick-up element (40S), and the said light transmission optical member (43) The imaging unit (40) is characterized in that the distance between them is 1 mm or more.
A seventh aspect of the present invention is a camera including the imaging unit (40) according to any one of the first to sixth aspects.

  ADVANTAGE OF THE INVENTION According to this invention, the imaging unit and camera which can suppress the internal reflection of image light and can obtain the image which suppressed generation | occurrence | production of flare can be provided.

It is a schematic structure sectional view of a camera to which an embodiment of the present invention is applied. FIG. 2 is a partial enlarged cross-sectional view of an imaging unit that is an enlarged view of a part A in FIG. 1. It is a simulation result which shows generation | occurrence | production of the ghost in the optical LPF1 expanded by the predetermined ratio with respect to the effective pixel area. It is a simulation result which shows generation | occurrence | production of the ghost in the optical LPF2 expanded by the predetermined ratio with respect to the effective pixel area. It is a simulation result which shows generation | occurrence | production of the ghost in the optical LPF3 expanded by the predetermined ratio with respect to the effective pixel area. It is a simulation result which shows generation | occurrence | production of the ghost in the optical LPF4 expanded by the predetermined ratio with respect to the effective pixel area. It is a simulation result which shows generation | occurrence | production of the ghost in the optical LPF5 expanded by the predetermined ratio with respect to the effective pixel area.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic sectional view of a camera 1 to which an embodiment of the present invention is applied.
In the following explanatory diagrams, an XYZ orthogonal coordinate system is provided 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. In the following description, the Z plus direction toward the subject is also referred to as the front side, and the opposite Z minus side is also referred to as the back side.

The camera 1 is an interchangeable lens camera, and includes a camera body 10 and a lens barrel 20 that includes an imaging optical system 21 (shown in a simplified manner with one lens in FIG. 1). .
While the camera body 10 includes a body mount 10M, the lens barrel 20 includes a lens mount 20M, and the lens barrel 20 is coupled to the camera body 10 with the optical axis OA by coupling the body mount 10M and the lens mount 20M. It is mounted in a state where they are matched. Thereby, the lens barrel 20 can be attached to and detached from the camera body 10, and various lens barrels 20 having different focal lengths and functions can be used depending on the object to be photographed.

  The camera body 10 includes a body chassis 30, an imaging unit 40 attached to the body chassis 30, a shutter unit 50, an electronic viewfinder 60, an exterior member 70 that accommodates these components, and the like. A display device 75 is provided on the back side of the exterior member 70.

The body chassis 30 is a member constituting the skeleton of the camera body 10. The center of the front side of the body chassis 30 is open, and the body mount 10M is fastened to the outer surface of the opening by a mount screw.
An imaging unit 40 is mounted on the back side of the body chassis 30.

The imaging unit 40 includes, for example, a bracket 41, an imaging module 42 provided on the front side thereof, which includes an imaging element 40 </ b> S such as a CMOS or CCD that converts subject light into an electrical signal, and an optical low pass filter (Optical Low Pass Filter). : Hereinafter referred to as “optical LPF”) 43 and a pressing fixture 44 that presses the optical LPF 43 from the subject side in the optical axis direction, and these are configured as an integral unit.
The imaging unit 40 is mounted on the back side of the body chassis 30 via a bracket 41, and is provided so that the light receiving surface of the imaging element 40S is orthogonal to the optical axis OA. The imaging unit 40 will be described in detail later.

Although detailed description is omitted, the shutter unit 50 is a longitudinally running focal plane shutter, which is fixed to the body chassis 30 and disposed on the front side of the imaging unit 40.
The shutter unit 50 adjusts the exposure time of the subject light with respect to the image sensor 40S (the time during which the image sensor 40S accumulates the subject light) during photographing.

The electronic viewfinder 60 includes an imaging irradiation module 61 and an eyepiece optical system 62, and is arranged on the upper part of the camera body 10.
The electronic viewfinder 60 displays the through image captured by the image sensor 40S on the imaging irradiation module 61. The photographer can visually recognize the image displayed on the imaging irradiation module 61 through the eyepiece optical system 62. Thereby, it is possible to view the image picked up by the image pickup device 40S in real time like a so-called single-lens reflex without providing a quick return mirror.

  The display device 75 is configured by a liquid crystal panel or the like, and displays a through image captured by the image sensor 40S. Accordingly, it is possible to take a picture by looking at the image picked up by the image pickup device 40S via the display device 75 without looking into the electronic viewfinder 60.

  In the camera 1 configured as described above, the subject image formed on the image sensor 40S of the imaging unit 40 via the imaging optical system 21 of the lens barrel 20 is converted into an electric signal by the image sensor 40S. The imaging data photoelectrically converted by the imaging element 40S is subjected to signal processing as image data by a control device (not shown). The signal-processed image data is sent to the electronic viewfinder 60 and the display device 75, and is recorded in a recording device (not shown) at the time of photographing.

Next, the imaging unit 40 will be described in detail with reference to FIG.
FIG. 2 is a partial enlarged cross-sectional view of the imaging unit 40 which is an enlarged view of a part A in FIG.
As described above, in the imaging unit 40, the imaging module 42 including the imaging element 40S and the optical LPF 43 are attached to the bracket 41 by the press fixing body 44.

  A mask rubber 45 is interposed between the imaging module 42 and the optical LPF 43, and a cleaning unit 46 is disposed on the front surface of the pressing fixture 44 via a support portion 47. Although not described in detail, the cleaning unit 46 includes a transparent filter 46F, a vibrating body, and the like, and functions to vibrate the transparent filter 46F with the vibrating body and remove the attached dust. In the present embodiment, the cleaning unit 46 is also a constituent element of the imaging unit 40.

Hereinafter, each component of the imaging unit 40 will be described in order.
The bracket 41 is a plate having a predetermined thickness, and includes a support convex portion 41A that supports the imaging module 42 at the center, and a fixing portion to the body chassis 30 at the outer edge portion.
In the imaging module 42, an imaging element 40S, a concave package 42P opened to the front side, and a cover glass 42G are integrally configured with a predetermined accuracy. That is, the image sensor 40S is housed and disposed inside the package 42P, and the cover glass 42G covers the front side opening of the package 42P.
Further, in the image pickup element 40S, an area inside a predetermined distance on both sides of the short side and the long side from the edge is an effective pixel area 40R used for actual image pickup.

An imaging mounting board 42C is provided around the back side of the package 42P in the imaging module 42, and the imaging mounting board 42C is responsible for electrical connection between the imaging element 40S and the outside.
The imaging module 42 is attached to the support convex portion 41A of the bracket 41 on the back surface of the package 42P with an adhesive or the like having excellent thermal conductivity, and is provided so as to conduct heat generated by the imaging element 40S to the bracket 41 and dissipate heat. It has been.

  The optical LPF 43 is a filter that removes high-frequency components from subject image light incident on the light receiving surface of the image sensor 40S and suppresses the occurrence of moire or the like in the subject image. The optical LPF 43 is laminated and integrated with an infrared cut filter or the like, and is formed to have a predetermined thickness with a substantially similar rectangular shape that is a predetermined amount larger than the light receiving surface of the image sensor 40. The size of the optical LPF 43 will be described later.

The press fixing body 44 is formed in a rectangular frame shape capable of covering a mask rubber 45 described later by resin molding. An entrance opening 44A that defines the shape of the image light incident on the image sensor 40S in the image capture module 42 is formed at substantially the center of the pressing fixture 44.
A concave pressing portion 44B corresponding to the optical LPF 43 is formed around the back side of the entrance opening 44A.

Further, the inner peripheral end face of the incident opening 44A is inclined at a predetermined angle in a direction extending toward the back side, and the front side angle is an acute opening edge 44E. That is, the size and shape of the entrance opening 44A are defined by the opening edge 44E which is a corner on the front surface side.
Although not shown, the pressing fixing body 44 is fastened to the bracket 41 by a fastening member such as a screw, presses the optical LPF 43 by the pressing portion 44B, and is interposed between the optical LPF 43 and the imaging module 42. The mask rubber 45 is fixed to the bracket 41 as a unit.

The mask rubber 45 is provided with a rectangular substrate portion 45B having a mask opening 45A in the center and an edge portion 45C having a predetermined height that borders the back side of the outer edge portion thereof by an elastic rubber material (silicone rubber or the like). It is formed in a frame shape.
The substrate portion 45B has a plate shape with a predetermined thickness, and the periphery of the front side of the mask opening 45A is formed in a concave shape corresponding to the optical LPF 43 to form a filter seal portion 45D having a predetermined thickness thinner than the substrate portion 45B. Yes.

  The mask rubber 45 is extrapolated to the imaging module 42 from the front side, the peripheral portion of the substrate portion 45B is located between the front surface (cover glass 42G) of the imaging module 42 and the pressing member 45, and the filter seal portion 45D is optical. It is sandwiched between the LPF 43 and the cover glass 42G. In other words, the filter seal portion 45D is pressed against the cover glass 42G via the optical LPF 43 pressed by the pressing fixture 44.

  In the mask rubber 45 thus provided, the filter seal portion 45D is interposed between the optical LPF 43 and the cover glass 42G so as to form a predetermined gap without contacting them. Also, the filter seal portion 45D fills the space between the optical LPF 43 and the cover glass 42G, and the peripheral portion of the substrate portion 45B is between the pressing member 45 (accommodating step portion 45F) and the imaging module 42. It functions as a sealing material that prevents intrusion inside.

Next, the size of the optical LPF 43 will be described.
As indicated by a dotted line in FIG. 2, stray light A, A ′, B, and C from the outside may be incident on the imaging element 40 </ b> S of the imaging unit 40.
The stray light A ′ is stray light that is reflected by the side surface of the filter seal portion 45D of the mask rubber 45 and further reflected by the optical LPF 43 and incident on the effective pixel region 40R of the image sensor 40S.
The stray light A is stray light that is reflected by the inner peripheral end face of the edge 45E of the mask rubber 45 and enters the image sensor 40S.
The stray light B is stray light that is reflected by the opening edge 44E of the pressing fixture 44 and is incident on the image sensor 40S.
The stray light C is stray light that is reflected by the end of the support portion 47 of the cleaning unit 46 and is incident on the image sensor 40S.
Due to these stray lights, flare and ghost are generated in the photographed image.

  These stray lights A, A ′, B, and C are caused by respective factor portions (the side surface of the filter seal portion 45D of the mask rubber 45, the inner peripheral end surface of the edge 45E of the mask rubber 45, and the pressure fixing body 44). If the opening edge 44E and the end of the support portion 47 of the cleaning unit 46) are separated from the effective pixel region 40R of the image sensor 40S, the possibility of entering the effective pixel region 40R is considered to be low.

  These factor parts are arranged at the edge of the optical LPF 43. Therefore, if the optical LPF 43 is made larger than the effective pixel area 40R of the image sensor 40S, these factor parts are necessarily separated from the effective pixel area 40R of the image sensor 40S, and the occurrence of flare and ghost due to stray light can be suppressed. it is conceivable that.

  Therefore, in the case of a plurality of optical LPFs having different relative sizes with respect to the effective pixel region 40R of the image sensor 40S, a ghost incident on the effective pixel region 40R was simulated. The results are shown in FIGS.

  3 to 7 show the case of an optical LPF (LPF1, LPF2, LPF3, LPF4, LPF5) enlarged by a ratio shown in the table in each figure with respect to the vertical length, horizontal length, and area of the effective pixel region 40R. This is a simulation result.

  FIG. 3 shows a case where the vertical length of the optical LPF 43 is 166% of the vertical length of the effective pixel region 40R, the horizontal length is 145% of the horizontal length of the effective pixel region 40R, and the area is 241% of the area of the effective pixel region 40R. . In this case, the ghost intensity is strong in any of A ', A, B, and C, particularly in the upper part of the image.

  FIG. 4 shows a case where the vertical length of the optical LPF 43 is 177% of the vertical length of the effective pixel region 40R, the horizontal length is 148% of the horizontal length of the effective pixel region 40R, and the area is 262% of the area of the effective pixel region 40R. . In this case, ghosts from A ', A, B, and C are slightly weaker than those in FIG.

  FIG. 5 shows a case where the vertical length of the optical LPF 43 is 188% of the vertical length of the effective pixel region 40R, the horizontal length is 160% of the horizontal length of the effective pixel region 40R, and the area is 301% of the area of the effective pixel region 40R. . In this case, ghosts from A 'and C almost disappear.

  FIG. 6 shows a case where the vertical length of the optical LPF 43 is 199% of the vertical length of the effective pixel region 40R, the horizontal length is 167% of the horizontal length of the effective pixel region 40R, and the area is 323% of the area of the effective pixel region 40R. . In this case, the ghost from A 'and C disappears, and the ghost from A and B weakens.

  FIG. 7 shows a case where the vertical length of the optical LPF 43 is 209% of the vertical length of the effective pixel region 40R, the horizontal length is 174% of the effective pixel region 40R, and the area is 364% of the area of the effective pixel region 40R. In this case, there are no ghosts from A 'and C, and ghosts from A and B are sufficiently weak.

  As described above, from the simulation results shown in the drawing, the length (short side) of the optical LPF 43 is preferably 177% or more (more than the length of the LPF 2). More preferably, it is 188% or more (more than the longitudinal length of LPF3) in which ghosts from A ′ and C substantially disappear. Further, it is more preferable if the ghost from A and B is 209% (more than the longitudinal length of LPF5) at which the ghost is sufficiently weak.

  However, if the optical LPF 43 exceeds 200% (for example, LPF5), the manufacturing cost is increased, and it is not preferable from the viewpoint of securing specification values (such as expansion of thickness unevenness due to polishing). It is also contrary to downsizing.

  Therefore, in the embodiment, the vertical length of the optical LPF 43 is set to 195% of the vertical length of the effective pixel region 40R. Note that the length of the horizontal side has less influence on the ghost as the length of the vertical side. For this reason, the horizontal length of the optical LPF 43 is set to 152% of the horizontal length of the effective pixel region 40R without increasing the length of the short side from the viewpoint of cost and compactness. Further, the area ratio of the optical LPF 43 of this embodiment is 296% of the effective pixel region 40R.

As described above, this embodiment has the following effects.
The generally used optical LPF is about LPF1 shown in FIG. 3 and has a vertical length of 166% of the vertical length of the effective pixel region 40R and a horizontal length of about 145% of the horizontal length of the effective pixel region 40R. . In this case, even if the optical LPF is any of A ′, A, B, and C described above, a ghost is strongly generated particularly in the upper part of the image. However, in this embodiment, the vertical length is 195%, the horizontal side is 152%, and the area is The ratio is 296%. Therefore, the internal reflection of the image light is suppressed without generating a strong ghost like the LPF 1, and an image with reduced flare can be obtained.

(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.
The above embodiment is an example in which the present invention is applied to a camera body with interchangeable lenses that does not include a quick return mirror. However, the present invention is not limited to this, and may be applied to a camera body provided with a quick return mirror.

  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, 20: lens barrel, 30: body chassis, 40: imaging unit, 40S: imaging device, 40R: effective pixel area, 42: imaging module, 43: optical LPF, 44: pressure fixing Body, 44A: incident opening, 44E: opening edge, 45: mask rubber, 45A: mask opening, 45E: edge, 80: light shielding sheet, 81: light shielding opening, OA: optical axis

Claims (7)

A rectangular imaging device;
A rectangular light-transmitting optical member located on the front side of the imaging device;
With
The length of the short side of the light transmitting optical member is 177% or more and 200% or less of the length of the effective pixel region of the image sensor in the short side direction;
An imaging unit characterized by. The imaging unit according to claim 1,
The length of the long side of the light transmitting optical member is 148% or more of the length of the effective pixel region of the image sensor in the long side direction;
An imaging unit characterized by. The imaging unit according to claim 1 or 2,
The area of the light transmissive optical member is 262% or more of the area of the effective pixel region of the image sensor;
An imaging unit characterized by. The imaging unit according to any one of claims 1 to 3,
The length of the short side of the light transmitting optical member is 188% or more and 250% or less of the length of the effective pixel region of the image sensor in the short side direction;
An imaging unit characterized by. The imaging unit according to any one of claims 1 to 4,
The light transmitting optical member is an optical low-pass filter;
An imaging unit characterized by. The imaging unit according to any one of claims 1 to 5,
The distance between the surface of the image sensor and the light transmitting optical member is 1 mm or more,
An imaging unit characterized by.   A camera provided with the imaging unit of any one of Claims 1-6.