JP2020079873A - Imaging apparatus - Google Patents

Abstract

To enable a focusing screen and a visual field frame to be easily adjusted by materializing satisfactory assembly work efficiency in an imaging apparatus with a finder.SOLUTION: The finder comprises: a screen unit provided with a screen 71 on which an optical image is formed and a visual field frame 72 defining the observation range of the optical image formed on the screen; an ocular lens 75 for observing the observation range via a prism; and a lens holding member 101 holding the prism and the ocular lens. The imaging apparatus is provided with: a mirror 4 reflecting the optical image entered via an imaging optical system to the screen side; a mirror holding member 300 holding the mirror; and a spacer 302 with adjustable thickness and arranged between the mirror holding member and the screen unit, wherein the lens holding member is fixed to the mirror holding member, the screen unit abuts on the mirror holding member in the optical axis direction via the spacer and is movable in the optical axis direction and in a direction perpendicular to the optical axis.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an image pickup apparatus, and more particularly to adjustment of a finder unit mounted on the image pickup apparatus.

  Generally, an imaging device such as a digital camera including a finder unit such as an optical finder for observing an object is known. In this type of image pickup device, a mirror that is movable outside the photographing optical path is provided, and when observing a subject, the mirror is arranged in the photographing optical path and the optical image is reflected by the mirror to guide the optical image to the optical finder. . On the other hand, at the time of shooting, the mirror is flipped up and retracted out of the shooting optical path, and an optical image is formed on the image sensor to perform shooting.

  In such an image pickup apparatus, it is desirable that the focus of the focusing screen on which the optical image (subject image) is formed in the optical finder and the focus of the image pickup element are substantially the same. Therefore, in the manufacturing process of the image pickup apparatus, in order to match the focus on the focusing screen with the focus on the image pickup element, it is necessary to perform highly accurate adjustment in the optical axis direction.

  Furthermore, in the above-described image pickup apparatus, it is desirable that the observation range in the optical finder and the image pickup range in the image pickup element are substantially the same. Therefore, in the manufacturing process of the imaging device, in order to guarantee the field of view, which is a value that indicates the degree of coincidence between the observation range and the imaging range, the field of view frame that determines the observation range is highly accurately measured in the direction perpendicular to the optical axis. Need to be adjusted.

  In order to perform the above adjustment, for example, there is one in which the thickness of the spacers arranged on the focusing screen is changed to adjust the focusing screen in the optical axis direction (Patent Document 1).

  Therefore, in Patent Document 1, the finder unit is attached to a mirror box that holds a mirror, and the focusing screen, the field frame, and the spacer are fixed to the holding member by a spring. In Patent Document 1, the holding member is movable along a plane perpendicular to the optical axis, and the field frame is adjusted in the direction perpendicular to the optical axis by moving the holding member.

JP, 2017-68183, A

  However, in Patent Document 1 described above, in order to change the thickness of the spacer when adjusting in the optical axis direction, it is necessary to remove the spring and the focusing screen and change the thickness of the spacer from the mirror box side. Therefore, in Patent Document 1, when the spacer is attached, it is necessary to assemble the spacer while avoiding the mirror provided in the mirror box, which is extremely troublesome to assemble.

  Therefore, an object of the present invention is to provide an image pickup apparatus which can improve the assembling workability and can easily adjust the focusing screen and the field frame.

  In order to achieve the above object, an image pickup apparatus according to the present invention is an image pickup apparatus including a finder unit for observing an optical image, wherein the finder unit has a focusing screen on which an optical image is formed, and the focusing unit. A focusing screen unit provided with a field frame that defines the observation range of the optical image formed on the screen, an eyepiece for observing the observation range through a prism, and holding the prism and the eyepiece lens. And a mirror holding member for holding the mirror, the mirror holding member for reflecting the optical image incident through the imaging optical system to the focusing screen side, and the mirror holding member. And a spacer having a thickness adjustable between the focusing screen unit and the focusing screen unit, the lens holding member is fixed to the mirror holding member, and the focusing screen unit holds the mirror through the spacer. It is characterized in that it is in contact with the member in the optical axis direction and is movable in the optical axis direction and in a direction perpendicular to the optical axis.

  According to the present invention, the assembling workability is improved, and the focusing screen and the field frame can be easily adjusted.

It is a figure which shows an example of the imaging device provided with the finder unit by the 1st Embodiment of this invention. It is a perspective view which decomposes|disassembles and shows the structure of the finder unit and imaging unit which are shown in FIG. It is a perspective view which decomposes|disassembles and shows the penta unit shown in FIG. It is a perspective view which decomposes|disassembles and shows the screen unit shown in FIG. It is the figure which looked at the finder unit and mirror box shown in FIG. 1 from the upper side. It is sectional drawing which followed the AA line shown in FIG. It is a figure which shows the cross section along the AA line shown in FIG. 5 about the finder unit and mirror box used with the camera which concerns on the 2nd Embodiment of this invention.

  Hereinafter, an example of an imaging device including a finder unit according to an embodiment of the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is a diagram showing an example of an image pickup apparatus including a finder unit according to the first embodiment of the present invention. In the following description, a digital single-lens reflex camera (hereinafter simply referred to as a camera) will be described as an example of the image pickup apparatus.

  The camera has a camera body (imaging device body) 1, and a detachable taking lens unit (hereinafter simply referred to as a taking lens) 2 is attached to the camera body 1. The taking lens (imaging optical system) 2 is provided with a taking optical system 21 and a diaphragm 22 for adjusting the exposure amount. In the illustrated example, the taking optical system 21 is shown as a single lens, but actually it is made up of a plurality of lens groups.

  The taking lens 2 is electrically and mechanically connected to the camera body 1 via a lens mount (also simply referred to as a mount) 3. Further, in the photographing lens 2, a focus mechanism provided in the photographing optical system 21 is moved along the optical axis by a drive mechanism (not shown) to perform focus adjustment.

  The camera body 1 is provided with a movable half mirror 4. The half mirror 4 reflects and transmits an optical image incident via the photographing optical system 21. That is, the half mirror 4 divides one optical path into two optical paths.

  A movable sub-mirror 5 (total reflection mirror) is arranged at the subsequent stage of the half mirror 4, and the sub-mirror 5 reflects the optical image transmitted through the half mirror 4 and guides it to the focus detection unit 6. The focus detection unit 6 performs focus detection by a so-called phase difference detection method according to the optical image.

  The finder unit 7 includes a focusing screen 71, a field frame 72, a PN-LCD 73, a pentaprism 74, an eyepiece lens unit 75, an information display member 76, a display prism 77, a photometric sensor 78, and a photometric lens 79. The optical image reflected by the half mirror 4 is formed on the focusing screen 71.

  The field frame 72 is arranged directly above the focusing screen 71, and has an opening that defines the observation range of the optical image. The PN-LCD 73 is a polymer-dispersed liquid crystal panel made of a polymer-dispersed liquid crystal that is in a diffusion state when not energized and is in a transmission state when energized. The PN-LCD 73 is arranged on the field frame 72.

  On the PN-LCD 73, information regarding the camera is displayed in the observation range. The optical image formed on the focusing screen 71 passes through the PN-LCD 73 and is guided via the pentaprism 74 to the eyepiece lens unit 75 having a plurality of lenses. The photographer can observe the optical image by the eyepiece lens unit 75.

  The information display member 76 displays the setting information related to the camera outside the observation range. The light emitted from the information display member 76 enters the penta prism 74 via the display prism 77. The photographer can see the setting information below the observation range via the eyepiece lens unit 75.

  The photometric sensor 78 detects diffused light from the focusing screen 71 via the photometric lens 79, and photometrically measures the subject based on the detection result, to obtain, for example, luminance information.

  An image pickup unit 8 is arranged after the half mirror 4, and the image pickup unit 8 has an image pickup element 81 such as a CCD or CMOS sensor and an optical low-pass filter 82. The image sensor 81 is driven one-shot or continuously, and a still image or a moving image is obtained according to the output (image signal) of the image sensor 81. An image pickup range indicating the range of the image picked up by the image pickup element 81 is determined.

  The optical low-pass filter 82 cuts a component having a frequency equal to or higher than a predetermined cutoff frequency in the subject image (optical image) and forms an optical image on the image sensor 81.

  As shown in the figure, a focal plane shutter 9 for adjusting the amount of light incident on the image sensor 81 is arranged between the sub mirror 5 and the image pickup unit 8.

  When the photographing operation is performed, the half mirror 4 and the sub mirror 5 are flipped up, the exposure amount is controlled by the focal plane shutter 9, and an optical image is formed on the image sensor 81. That is, shooting is performed. Then, after photographing, the half mirror 4 and the sub mirror 5 are returned to the positions (positions on the optical axis) shown in FIG.

  FIG. 2 is an exploded perspective view showing the configurations of the finder unit and the image pickup unit shown in FIG. 2A is a perspective view seen from the front side, and FIG. 2B is a perspective view seen from the back side.

  The finder unit 7 shown in the figure is separated into a penta unit 100 and a screen unit (focusing screen unit) 200. The penta unit 100 is fixed to a mirror box (mirror holding member) 300 with screws 301. As will be described later, the screen unit 200 contacts the mirror box 300 via the washer 302 in the optical axis direction.

  The half mirror 4 is held in the mirror box 300, and the half mirror 4 is driven by a mirror driving mechanism (not shown). As a result, the state in which the finder unit 7 observes the subject (observation state) and the state in which the imaging unit 8 captures an image (imaging state) are switched. Further, the mount 3 is held in the mirror box 300, and the taking lens 2 (not shown in FIG. 2) is attached to the mount 3 while being in contact with the lens attachment surface 3a.

  The imaging unit 8 is positioned with respect to the mirror box 300 in a direction perpendicular to the optical axis, and is fixed to the mirror box 300 by adjusting screws 303. A coil spring 304 is arranged between the mirror box 300 and the imaging unit 8, and the coil spring 304 urges the imaging unit 8 toward the adjustment screw 303 side.

  When the image pickup unit 8 is moved along the optical axis by adjusting the position of the adjusting screw 303, the optical distance (flange back) from the lens mounting surface 3a to the image pickup surface of the image pickup element 81 can be adjusted. it can.

  As described above, the finder unit 7, the image pickup unit 8, the half mirror 4, and the mount 3 are held in the mirror box 300. Further, the mirror box 300 holds the sub-mirror 5, the focus detection unit 6, and the focal plane shutter 9, but the illustration is omitted here for simplification of the drawing.

  FIG. 3 is an exploded perspective view of the penta unit shown in FIG.

  The penta unit 100 includes a penta prism 74, an eyepiece lens unit 75, a photometric sensor 78, and a photometric lens 79.

  The eyepiece unit 75 has four eyepieces: a first eyepiece lens 75a, a second eyepiece lens 75b, a third eyepiece lens 75c, and a fourth eyepiece lens 75d. The penta prism 74 and the eyepiece lens unit 75 are held by the penta holding member (lens holding member) 101. The second eyepiece lens 75b is movable in the optical axis direction for diopter correction, but since it is known, the description thereof is omitted here.

  The eyepiece lens lid 102 is fastened to the penta holding member 101 with screws 103, and the eyepiece lens lid 102 has a role of covering the eyepiece lens unit 75 so as not to come off in the direction perpendicular to the optical axis. Then, the photometric sensor 78 and the photometric lens 79 are adhesively fixed to the eyepiece lens lid 102.

  FIG. 4 is an exploded perspective view of the screen unit shown in FIG.

  As shown, the screen unit 200 has a focusing screen 71, a field frame 72, a PN-LCD 73, an information display member 76, and a display prism 77.

  The focusing screen 71 and the field frame 72 are held by the FS holding member 201. Then, the holding spring 202 is held by the FS holding member 201, and the holding screen 202 biases the focusing screen 71 and the field frame 72 in the optical axis direction with respect to the FS holding member 201.

  The PN-LCD 73, the information display member 76, and the display prism 77 are held by the PN holding member 203. Then, the PN holding member 203 is positioned with respect to the FS holding member 201 in the direction perpendicular to the optical axis. The arm portion 203b is a portion gripped by a tool when adjusting the visual field frame 72 described below in a direction perpendicular to the optical axis.

  The PN light guide 204 is disposed on the side surface of the PN-LCD 73 and guides light from an LED (not shown) to the PN-LCD 73. The PN mask 205 is arranged immediately above the PN-LCD 73 and determines the display range on the PN-LCD 73. Double-sided tapes are arranged on the front and back of the PN mask 205, one side of which is fixed to the PN holding member 203, and the other side of which is fixed the PN-LCD 73 and the PN light guide 204.

  The display light guide 206 is disposed on the back surface of the information display member 76 and guides light from an LED (not shown) to the information display member 76. The display light guide holding member 207 holds the display light guide 206.

  The reflection sheet 208 is disposed on the back surface of the display light guide 206, and reflects the light, which is guided by the display light guide 206 and is emitted to the reflection sheet 208 side, to the information display member 76 side. The display light guide mask 209 is disposed between the information display member 76 and the display light guide 206, and determines the range in which the light guided by the display light guide 206 illuminates the information display member 76.

  The information display member 76, the display light guide 206, the display light guide holding member 207, the reflection sheet 208, and the display light guide mask 209 are fixed to the PN holding member 203 by the fixing plate 210.

  The display mask 211 is arranged immediately above the display prism 77, determines the display range of the information display member 76, and blocks light outside the observation range.

  The first elastic member (first elastic body) 212 is arranged between the PN holding member 203 and the penta holding member 101. Then, the first elastic member 212 is compressed by the PN holding member 203 and the penta holding member 101, so that the PN holding member 203 is biased toward the FS holding member 201. Further, the first elastic member 212 surrounds the observation range and the outside of the display range of the information display member 76 on the entire circumference, and prevents dust from entering between the FS holding member 201 and the penta holding member 101 from the outside. To prevent.

  The second elastic member (second elastic body) 213 is arranged between the FS holding member 201 and the PN-LCD 73. The second elastic member 213 is compressed by the FS holding member 201 and the PN holding member 203, so that the FS holding member 201 is biased toward the washer 302 and the PN holding member 203 is biased toward the penta holding member 101. To be done. Further, the second elastic member 213 entirely surrounds the observation range and the outside of the display range of the information display member 76, and prevents dust from entering between the FS holding member 201 and the PN holding member 203 from the outside. To prevent.

  Here, the above-mentioned screen unit will be further described.

  FIG. 5 is a view of the finder unit and the mirror box shown in FIG. 1 as viewed from above. 6 is a sectional view taken along the line AA shown in FIG.

  The biasing force of the first elastic member 212 described above is larger than the biasing force of the second elastic member 213, and the PN holding member 203 abuts the FS holding member 201 in the optical axis direction by the convex portion 203a. Further, the FS holding member 201 abuts the washer 302 at the convex portion 201a by the urging force of the first elastic member 212 and the second elastic member 213.

  Therefore, by changing the thickness of the washer 302 (the thickness of the washer 302 can be adjusted), the FS holding member 201 and the PN holding member 203 can be moved in the optical axis direction. Therefore, members such as the focusing screen 71, the field frame 72, the PN-LCD 73, and the information display member 76 held by the FS holding member 201 and the PN holding member 203 also move in the optical axis direction by changing the thickness of the washer 302. Can be made.

  As described above, the PN holding member 203 can move the arm 203b in the direction perpendicular to the optical axis by gripping the arm 203b with a jig. Since the FS holding member 201 is positioned on the PN holding member 203 in the direction perpendicular to the optical axis, it can be moved together with the PN holding member 203. Therefore, members such as the focusing screen 71, the field frame 72, the PN-LCD 73, and the information display member 76 held by the FS holding member 201 and the PN holding member 203 can also be moved in the direction perpendicular to the optical axis.

  Here, the adjustment in the optical axis direction of the focusing screen 71 and the adjustment in the direction perpendicular to the optical axis of the field frame 72 will be described.

  In the illustrated camera, the position of the image sensor 81 is first determined. The position of the image pickup element 81 in the direction perpendicular to the optical axis is determined by fixing the image pickup element 81 to the mirror box 300 with the adjusting screw 303, and thereby the position of the image pickup range in the direction perpendicular to the optical axis is determined. It is determined.

  Next, the flange back is measured with a known tool, and the position of the image pickup element 81 in the optical axis direction is adjusted by the adjusting screw 303 so that the image pickup surface comes to a predetermined flange back position.

  Then, the position of the focusing screen 71 in the optical axis direction is determined. First, the finder unit 7 is fixed to the mirror box 300 without the washer 302. Then, the optical distance from the lens mounting surface 3a to the image forming surface of the focusing screen 71 is measured to calculate the difference between the flange back and the optical distance from the lens mounting surface 3a to the image forming surface of the focusing screen 71.

  Next, the finder unit 7 is removed from the mirror box 300, and the washer 302 is attached to the mirror box 300 in the optical axis direction. At this time, the thickness of the washer 302 is made substantially the same as the difference between the above-mentioned flange back and the optical distance from the lens mounting surface 3a to the image forming surface of the focusing screen 71.

  After that, the finder unit 7 is fixed to the mirror box 300 again so that the focusing screen 71 is brought into focus with the image pickup element 81. At this time, the PN-LCD 73 and the information display member 76 as well as the focusing screen 71 are adjusted in the optical axis direction. Therefore, the diopter of the focusing screen 71, the PN-LCD 73, and the information display member 76 does not shift due to the adjustment of the focusing screen 71 in the optical axis direction.

  Further, since the washer 302 is assembled in the optical axis direction with respect to the mirror box 300 from which the finder unit 7 is removed, the assembly is extremely easy.

  Finally, the position of the field frame 72 in the direction perpendicular to the optical axis is determined. First, the position of the photographing range is measured with a tool. Next, the position of the field frame 72 in the direction perpendicular to the optical axis is measured with a tool via the eyepiece lens unit 75. Then, the difference is calculated based on the imaging range obtained by the measurement and the position of the field frame 72. According to the difference, the arm 203b is gripped by a tool and the PN holding member 203 is moved in a direction perpendicular to the optical axis, and the observation range is adjusted to be substantially the same as the imaging range.

  After adjustment in the direction perpendicular to the optical axis of the field frame 72, the arm portion 203b of the PN holding member 203 is adhesively fixed to the penta holding member 101.

  The visual field ratio is related to not only the position of the visual field frame 72 in the optical axis direction but also the size of the opening of the visual field frame 72 (manufacturing error of the opening). Therefore, in a camera with a high visual field ratio (about 100%), it is necessary to adjust the focusing screen 71 in the direction perpendicular to the optical axis of the visual field frame 72 more accurately than in the optical axis direction.

  Further, due to a manufacturing error of the FS holding member 201, the washer 302, and the like, when performing either one of the adjustment of the focusing screen 71 in the optical axis direction and the adjustment of the field frame 72 in the direction perpendicular to the optical axis, , The other position adjustment changes slightly. Therefore, as described above, if the adjustment in the direction perpendicular to the optical axis of the field frame 72 is performed after the adjustment in the direction of the optical axis of the focusing screen 71, the adjustment in the direction perpendicular to the optical axis of the field frame 72 is performed. Can be performed with high precision.

  Further, the screen unit 200 is biased by the first elastic member 212 toward the washer 302. Accordingly, when the PN holding member 203 is adhesively fixed to the penta holding member 101, it is possible to prevent the position of the PN holding member 203 from being displaced due to contraction during curing of the adhesive material.

  In the above example, the PN holding member 203 contacts the FS holding member 201 by the first elastic member 212, but the PN holding member 203 and the FS holding member 201 may be fixed by screws.

  As described above, in the first embodiment of the present invention, the assembling workability is improved, and the focusing screen and the field frame can be easily adjusted.

[Second Embodiment]
Next, an example of a camera including the finder unit according to the second embodiment of the present invention will be described. The configuration of the camera according to the second embodiment is the same as that of the camera shown in FIG. 1, and the configurations of the finder unit and the imaging unit are the same as the examples shown in FIGS.

  FIG. 7 is a view showing a cross section taken along line AA shown in FIG. 5 of the finder unit and the mirror box used in the camera according to the second embodiment of the present invention.

  Referring to FIGS. 5 and 7, the biasing force of first elastic member 212 is smaller than the biasing force of second elastic member 213, and PN holding member 203 has a convex portion 203c with respect to penta holding member 101. Abut in the optical axis direction. Further, the FS holding member 201 contacts the washer 302 at the convex portion 201a by the biasing force of the second elastic member 213.

  Therefore, the FS holding member 201 can be moved in the optical axis direction by changing the thickness of the washer 302. Therefore, members such as the focusing screen 71 and the field frame 72 held by the FS holding member 201 can also be moved in the optical axis direction by changing the thickness of the washer 302.

  Moreover, the PN holding member 203 can be moved in a direction perpendicular to the optical axis by grasping the arm portion 203b with a jig. Since the FS holding member 201 is positioned with respect to the PN holding member 203 in a direction perpendicular to the optical axis, it can be moved together with the PN holding member 203. Therefore, members such as the focusing screen 71, the field frame 72, the PN-LCD 73, and the information display member 76 held by the FS holding member 201 and the PN holding member 203 can also be moved in the direction perpendicular to the optical axis.

  Note that the adjustment of the focusing screen 71 in the optical axis direction and the adjustment of the field frame 72 in the direction perpendicular to the optical axis are the same as those in the first embodiment described above, and a description thereof will be omitted.

  The second embodiment is used when the PN holding member 203 cannot move in the optical axis direction, for example, when the gap between the penta holding member 101 and the PN holding member 203 is smaller than the change amount of the thickness of the washer 302. . Then, in the second embodiment, only the FS holding member 201 is moved in the optical axis direction to adjust the focusing screen 71 in the optical axis direction.

  As described above, also in the second embodiment of the present invention, the assembling workability is improved and the focusing screen and the field frame can be easily adjusted.

  Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the gist thereof.

1 Camera Main Body 3 Mount 4 Half Mirror 7 Finder Unit 71 Focusing Screen 72 Field of View Frame 73 PN-LCD
74 Penta prism 75 Eyepiece unit 81 Image sensor

Claims (8)

An imaging device comprising a finder unit for observing an optical image,
A focusing screen unit provided with the finder unit, a focusing screen on which an optical image is formed, and a field frame defining an observation range of the optical image formed on the focusing screen,
An eyepiece for observing the observation range through a prism,
A lens holding member for holding the prism and the eyepiece lens is provided,
A mirror that reflects the optical image incident through the imaging optical system toward the focusing screen side;
A mirror holding member for holding the mirror,
A spacer disposed between the mirror holding member and the focusing screen unit, the thickness of which is adjustable,
The lens holding member is fixed to the mirror holding member, and the focusing screen unit is in contact with the mirror holding member in the optical axis direction via the spacer to move in the optical axis direction and a direction perpendicular to the optical axis. An imaging device characterized by being movable.   The image pickup apparatus according to claim 1, wherein the focusing screen unit is provided with a display member that displays at least the setting information related to the image pickup apparatus in the visual field frame or outside the visual field frame. A first elastic body is arranged between the focusing screen unit and the lens holding member,
The imaging device according to claim 2, wherein the first elastic body urges the focusing screen unit toward the spacer. The focusing screen unit includes a first holding member that holds the focusing screen and the field frame,
A second holding member for holding the display member,
A second elastic body is arranged between the first holding member and the second holding member, and the urging force of the first elastic body is larger than the urging force of the second elastic body. The image pickup apparatus according to claim 3, wherein The focusing screen unit includes a first holding member that holds the focusing screen and the field frame,
A second holding member for holding the display member,
A second elastic body is arranged between the first holding member and the second holding member, and the urging force of the first elastic body is smaller than the urging force of the second elastic body. The image pickup apparatus according to claim 3, wherein A lens mount to which the image pickup optical system is attached is disposed on the mirror holding member,
An imaging element that outputs the image signal corresponding to the optical image by forming the optical image through the imaging optical system,
The thickness of the spacer is changed based on the optical distance from the lens mount to the image forming surface of the image pickup device and the optical distance from the lens mount to the image forming surface of the focusing screen, thereby changing the thickness of the focusing screen unit. The image pickup apparatus according to claim 1, wherein a first adjustment for adjusting a position in the optical axis direction is performed.   The second adjustment for adjusting the position of the focusing screen unit in the direction perpendicular to the optical axis is performed based on the imaging range of the imaging element and the observation range of the field frame. Imaging device.   The image pickup apparatus according to claim 7, wherein the second adjustment is performed after the first adjustment.