JP2012088633A - Finder device and imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a finder device that is excellent in the visibility of a subject and eliminates the need for a size increase.SOLUTION: The finder device comprises: a third lens 109c arranged closest to the observation side among eyepiece lenses 109; a first lens holder 200 having a projection Z forming an opening Z0 limiting a luminous flux entering the third lens; and an eyepiece frame 210 holding a flange portion Y together with the first lens holder. The third lens comprises: an inflecting part X configured to alter the inclination angle of an end face closer to the observation side than to the flange portion; a first end face Q located on the object side of the inflecting part and inclining so as to be away from an optical axis La from the inflecting part in the direction H toward the object side from the observation side; and a second end face R located closer to the observation side than to the inflecting part and inclining so as to be away from the optical axis in the direction H. On a cross-section including the optical axis, an end part Z2 closest to the optical axis of the projection is closer to the optical axis than to the inflecting part and closer to the optical axis than to the place U1 where an extension line U0 extended from the second end face R intersects the projection.

Description

  The present invention relates to a finder device and an imaging device.

  When unnecessary light enters the optical path of the finder optical system of a single-lens reflex camera, the unnecessary light is reflected by the eyepiece lens and its holding member and enters the photographer's field of view, reducing the visibility when the photographer observes the subject. . In order to solve this problem, Patent Document 1 proposes shielding the peripheral luminous flux of the eyepiece by using a light shielding sheet material, light shielding paint, printing, etc., and Patent Document 2 proposes that the finder opening on the eyepiece lens side. It is proposed to provide a protrusion at the edge.

JP 2002-82370 A JP-A-8-220597

  However, since the means proposed in Patent Documents 1 and 2 both provide new parts and processes, the cost is increased and the viewfinder device and the imaging device are enlarged.

  Accordingly, an object of the present invention is to provide a finder device and an imaging device that are excellent in visibility of a subject and do not increase in size.

  A finder device of the present invention is a finder device that enables an optical image formed by a light beam that has passed through an objective lens to be observed through a finder optical system having an eyepiece lens, around an optical unit that has an imaging function. A first lens holding member having a held portion provided and having a final lens disposed on the most observation side of the eyepieces and a protrusion forming an opening for restricting an incident light beam to the final lens; And a second lens holding member that is disposed closer to the observation side than the first lens holding member and holds the held portion of the final lens together with the first lens holding member. The lens is positioned between a boundary portion that changes an inclination angle of an end surface on the observation side with respect to the held portion, and between the boundary portion and the held portion, and in a direction from the observation side toward the object side. A first end face that is inclined so as to be separated from the optical axis of the finder optical system from the boundary portion, and is positioned closer to the observation side than the boundary portion, and is inclined so as to be separated from the optical axis of the finder optical system in the direction. A cross section including the optical axis, and an end portion of the projection of the first lens holding member that is closest to the optical axis is closer to the optical axis than the boundary portion. And the said edge part is near the said optical axis rather than the position where the extension line which extended the said 2nd end surface cross | intersects the said processus | protrusion.

  ADVANTAGE OF THE INVENTION According to this invention, the finder apparatus and imaging device which are excellent in the visibility of a to-be-photographed object and do not cause an enlargement can be provided.

It is a fragmentary sectional view of the finder apparatus of this embodiment. It is a schematic sectional drawing of the imaging device of a present Example. It is a schematic sectional drawing of another state of the imaging device shown in FIG. It is a disassembled perspective view of the finder apparatus of the imaging device shown in FIG. It is sectional drawing of the finder apparatus shown in FIG. It is sectional drawing for demonstrating the effect of the finder apparatus shown in FIG.

  2 and 3 are schematic cross-sectional views of the single-lens reflex digital camera (imaging device) of the present embodiment. The camera is configured such that the lens device 102 can be attached to and detached from the camera body 101.

  FIG. 2 shows a state in which an object can be observed by a photographer using an optical viewfinder (OVF), and the state shown in FIG. 2 is hereinafter referred to as an “OVF mode”. FIG. 3 shows a state in which the subject can be observed by the photographer using an electronic viewfinder (EVF) that sequentially displays the subject image on the display unit 107 attached to the back surface of the camera body 101. Hereinafter, the state shown in FIG. 4 is referred to as “EVF mode”.

  In the lens apparatus 102, a photographing optical system 103 for forming a subject image (optical image) and a diaphragm 104 for adjusting the exposure amount are provided. In FIG. 2, L1 represents the optical axis of the photographing optical system 103.

  The camera body 101 includes an image sensor 106 such as a CCD sensor or a CMOS sensor that photoelectrically converts an optical image formed by the photographing optical system 103, and obtains an image signal. The image sensor 106 is housed in a package 110.

  The image signal from the image sensor 106 is processed and displayed on the display unit 107 as image data. Further, the image signal photographed by the image sensor 106 is recorded in a recording unit (not shown).

  Reference numeral 111 denotes a movable half mirror (main mirror) that reflects part of the light beam incident from the photographing optical system 103 and transmits the remaining part. A movable sub mirror 122 is provided behind the half mirror 111 (on the image plane side), and reflects the light beam that has passed through the half mirror 111 to guide it to a focus detection unit (not shown). The sub mirror 122 is configured to be able to advance and retract with respect to the photographing optical path in conjunction with the half mirror 111. The half mirror 111 and the sub mirror 122 are arranged at the mirror down position shown in FIG. 2 in the OVF mode and at the mirror up position shown in FIG. 3 in the EVF mode. Reference numeral 113 denotes a focal plane shutter that adjusts the amount of light incident on the image plane, and has a front curtain and a rear curtain composed of a plurality of light shielding blades.

  The optical viewfinder is configured as a viewfinder device. 2 and 3 simply show that the finder apparatus has the focusing screen 105, the hollow penta112, the information display unit 180 in the optical finder, and the eyepiece lens 109. It has the following components.

  The focusing screen 105 is disposed on the planned image plane of the subject image formed by the photographing optical system 103. A mirror is deposited inside the hollow penta 112. Reference numeral 180 denotes an information display unit in the optical viewfinder for displaying specific information on the focusing screen 105. The eyepiece lens 109 is a lens group for observing a subject image formed on the focusing screen 105.

  The focusing screen 105, the hollow penta 112 and the eyepiece lens 109 constitute a finder optical system. In FIG. 2, La represents the optical axis of the finder optical system. The viewfinder device is a device that enables a photographer to observe an image formed by the photographing optical system (objective lens) 103 using a viewfinder optical system having an eyepiece lens 109.

  A release button (not shown) is pressed in two steps, and a shooting preparation operation (photometry operation, focus adjustment operation, etc.) is started by a half-press operation (ON of the switch SW1). Further, a shooting operation (running of the focal plane shutter 113, exposure of the image sensor 106, reading of the charge signal, and processing of the charge signal and image data obtained by processing the charge signal by full-pressing operation (ON of the switch SW2) is performed. Recording) starts.

  In the OVF mode shown in FIG. 2, the aperture 104 is in the open state, the front and rear curtains of the focal plane shutter 113 are charged, the front curtain is closed, the rear curtain is open, and the image sensor 106 is Not exposed. The light beam of the subject image incident from the photographing optical system 103 is reflected by the half mirror 111 and guided to the finder optical system, and the light beam transmitted through the half mirror 111 is reflected by the sub mirror 122 and guided to a focus detection unit (not shown). It is burned. Therefore, the photographer can observe the subject image through the eyepiece lens 109 and can perform focus detection by the focus detection unit.

  In the EVF mode shown in FIG. 3, the half mirror 111 and the sub mirror 122 are retracted from the photographing optical path, the light beam from the photographing optical system 103 is guided to the image sensor 106, and the subject image is continuously captured by the image sensor 106. Subject images are sequentially displayed on the unit 107. As a result, the photographer can determine the composition while confirming the subject image displayed on the display unit 107.

  FIG. 4 is a more detailed exploded perspective view of the viewfinder device. FIG. 5 is a longitudinal sectional view of the finder apparatus, and FIG. 6 is a transverse sectional view of the finder apparatus.

  Reference numeral 200 denotes a first lens holder (first lens holding member) that holds the eyepiece 109, 201 denotes a focus washer that adjusts the position of the focusing screen 105, and 202 holds the focusing screen 105 to the first lens holder 200. It is a spring member. Reference numeral 203 denotes a field frame that limits the field size of a light beam incident on the finder optical system. Reference numeral 204 denotes a mirror that performs image reversal together with the hollow penta 112 and folds the subject image transmitted through the field frame 203 in the direction of the eyeball of the photographer to form an erect image. Reference numeral 205 denotes a spring member for fixing and holding the hollow penta 112 to the first lens holder 200.

  The eyepiece lens 109 is composed of a plurality of lens groups. In this embodiment, as shown in FIGS. 4 to 6, the eyepiece lens 109 includes a first lens (plano-concave lens) 109a and a second lens in order from the object side to the observation side along the optical axis La of the finder optical system. It has a lens (biconvex lens) 109b and a third lens (convex / concave lens) 109c. Note that the eyepiece lens 109 may further include another lens, and the shape of each lens is not limited to these.

  The first lens 109 a is bonded and fixed to the first lens holder 200.

  The second lens 109b is bonded and fixed to the second lens holder 208. The second lens holder 208 is housed in the first lens holder 200 and configured to be movable with respect to the first lens holder 200. Yes.

  Specifically, the second lens holder 208 has a hole for fitting with the shaft 206 and a shaft (not shown) that guides the spring 207 that biases the second lens 109b toward the observation side. Since the shaft 206 is fitted into the fitting hole provided in the first lens holder 200 and the fitting hole of the second lens holder 208, the second lens holder 208 is configured to be slidable in the finder optical axis direction. Has been. The diopter (finder diopter) can be adjusted to any position by moving the second lens 109b in the finder optical axis direction via the gear and the cam 209. The moving mechanism of the second lens 109b in the finder optical axis direction is not limited.

  The third lens 109c is bonded and fixed to the first lens holder 200. The third lens 109c is the final lens arranged on the most observation side among the eyepiece lenses. The third lens 109c has a portion (a flange portion Y to be described later) sandwiched between the eyepiece frame 210 and the first lens holder 200. The eyepiece frame 210 functions as a third lens holding member disposed on the observation side with respect to the first lens holder 200.

  As shown in FIG. 6, the eyepiece frame 210 has a recess A, which is a second lens holding member into which an exterior part (not shown) is inserted. By forming the eyepiece frame 210 so as to surround the exterior part, the effect of dustproof and drip-proof is achieved.

  The eye cup 211 has projections 211a and 211b in the optical axis direction, and is attached by inserting the projections 211a and 211b into rail grooves 210a and 210b provided in the eyepiece frame 210, thereby improving the photographer's feeling of use. .

  FIG. 1 is a partial sectional view showing detailed shapes of the third lens 109c, the first lens holder 200, and the eyepiece frame 210 in a section including the optical axis La of the finder optical system.

  The third lens 109c has an incident surface F1 on which the light beam from the photographing optical system 103 is incident and an emission surface F2 on which the light beam from the photographing optical system 103 is emitted. The entrance surface F1 and the exit surface F2 constitute the front and back surfaces of the optical unit having the image forming action of the third lens 109c.

  The third lens 109c has a flange portion Y, a first end surface Q, and a second end surface R. Further, the eyepiece frame 210 has two end faces that are in contact with the first end face Q and the second end face R, respectively.

  The flange portion Y is a held portion having a first surface Y1 which is a plane positioned and joined to the first lens holder 200, and a second surface Y2 which is held facing the eyepiece frame 210. is there. The flange portion Y is provided around the optical portion of the third lens 109c, protrudes radially outward from the optical portion, and has a substantially rectangular cross-sectional shape. The flange portion Y facilitates the holding and bonding of the third lens 109c by the first lens holder 200 and the eyepiece frame 210.

  The first end face Q is disposed on the object side of the second end face R, and is away from the optical axis La of the finder optical system from the inflection part X in the direction H from the observation side toward the object side. Are inclined at the first inclination angle θ1. The second end face R is inclined at a second inclination angle θ2 with respect to the optical axis La so as to be separated from the optical axis La of the finder optical system in a direction H from the observation side toward the object side. θ1 is larger than θ2 (θ1> θ2> 0). The first end surface Q and the second end surface R constitute part of a conical surface having different central angles.

  Thus, the inflection part X changes the inclination angle of the end surface of the third lens 109c that is closer to the observation side than the flange part Y. The first end face Q is located on the object side (between the inflection part X and the flange part Y) from the inflection part X, and the second end face R is located on the observation side from the inflection part X. The inflection portion X extends in the circumferential direction of the third lens 109c and forms a boundary portion (boundary line) between the first end surface Q and the second end surface R.

  The first lens holder 200 has a protrusion Z that forms an opening Z0 that restricts a light beam incident on the third lens 109c. The protrusion Z is disposed closer to the object side than the third lens 109c.

  The observation-side surface Z1 partially protrudes on the plane Z11 on which the first surface Y1 of the flange portion Y of the third lens 109c is joined and positioned, and the incident surface F1 of the third lens 109c. And an inclined surface Z12.

  Conventionally, the third lens 109 c is bonded to the eyepiece frame 210 and the eyepiece frame 210 is positioned with respect to the first lens holder 200. However, since the first lens 109a and the second lens 109b, which are the other eyepieces 109, are both mounted and positioned on the first lens holder 200, the third lens 109c is also the first lens holder. Positioning with respect to 200 is preferable in terms of aberration correction. Therefore, in this embodiment, the third lens 109c is configured to be joined and positioned with respect to the first lens holder 200 instead of the eyepiece frame 210. In this case, the first surface Y1 and the plane Z11 are parallel.

  Further, a hemispherical convex portion (not shown) may be formed on the first surface Y1, and may be joined and positioned on the plane Z11. The hemispherical convex portion is used to correct a mold for molding the third lens 109c. If the modification of the mold is limited to a part, the accuracy can be easily maintained and processed. The number of convex portions is not limited.

  FIG. 6 shows a light beam in the finder left-right direction (long side direction) when the second lens 109b has a diopter position of −1.0 deoptory, and the right half shows the lens shape described in FIG. 1 of the present embodiment. The left half shows the lens shape without the inflection part X. E is the observer's eye point (eyeball position), B is the finder effective light beam, C is the back-incident light beam of the lens without the inflection portion X, and D is the back-incident light beam of this embodiment.

  The inflection portion X is disposed on the observation side with respect to the flange portion Y, and the end surface (side surface) on the observation side with respect to the flange portion Y of the third lens 109c is divided into two end surfaces having different inclination angles. For this reason, for example, a portion P where the observation side surface of the flange portion Y and the end surface of the third lens 109c intersect in the left diagram of FIG.

  In the present embodiment, the end Z2 closest to the optical axis La of the protrusion Z is closer to the optical axis La than the inflection X in FIG. 1 (that is, the shortest distance between the end Z2 and the optical axis La varies). Shorter than the shortest distance between the curved portion X and the optical axis La). Further, in the present embodiment, the end Z2 is closer to the optical axis La than the position U1 at which the extended line U0 extending the second end surface R toward the subject intersects the projection Z (that is, the end Z2 and the optical axis). The shortest distance to La is shorter than the shortest distance between the position U1 and the optical axis La).

  The first end face Q has an inclination angle that does not generate light that reaches the photographer's field of view as back-incident light even if any light ray S incident from the opening of the eyepiece frame 210 is reflected on the first end face Q, and the eyepiece The shape of the recess A of the frame 210 is set to an angle that secures a moldable thickness T. The second end face R is set at an angle that does not generate light that reaches the photographer's field of view as back-incident light even if any light ray S incident from the opening of the eyepiece frame 210 is reflected by the second end face R. The first end face Q extends from the second end face R so as to be away from the optical axis La.

  FIG. 6 shows the effect of comparing the lens shape of the present embodiment with the lens shape without the inflection portion X.

  In the case of the lens shape without the inflection portion X, the incident light beam is reflected on the left and right side surfaces of the third lens 109c and reflected by the exit surface M on the observation side of the second lens 109b. There is a back-incident ray C that passes through and enters the photographer's field of view, and the visibility of the subject image is reduced.

  On the other hand, in the case of the lens shape of the present embodiment, the reverse incident light beam D is reflected on the left and right side surfaces of the third lens 109c, but the light beam is shielded by the surface Z1, and the reverse incident light beam D reaches the photographer's field of view. Never do. As a result, the visibility of the subject image is improved. Although the reverse incident light beams C and D are described with only one light beam in one direction, they are light generated in all four directions.

  As described above, in this embodiment, the inflection portion X is provided to prevent ghost of the eyepiece lens 109. In order to eliminate the ghost in the lens shape shown in the left diagram of FIG. 6, for example, as shown by the dotted line K in FIG. 6, the inclination angle is increased so that the end surface of the third lens is further away from the optical axis La. It is possible. However, this increases the size of the third lens, resulting in an increase in size of the finder device, and hence the imaging device.

  Therefore, in this embodiment, the ghost is prevented by providing the inflection portion X with the minimum enlargement that forms the first end face Q. Further, in this embodiment, only the shape of the end face of the eyepiece frame 210 corresponding to the end face of the third lens 109c is adjusted, and a new part or printing process is not added, thereby preventing an increase in cost. it can. In addition, the attachment of various accessories is not hindered.

  As mentioned above, although the preferable Example of this invention was described, this invention is not limited to these Examples, A various deformation | transformation and change are possible within the range of the summary.

  The finder apparatus of the present embodiment can be applied to an imaging apparatus, and the imaging apparatus can be applied to use for imaging a subject.

109 Eyepiece 109c Third lens (final lens)
200 First lens holder (first lens holding member)
210 Eyepiece frame (second lens holding member)
Q First end surface R Second end surface La Optical axis Z Projection Z0 Opening Z1 Surface Z2 End U0 Extension line U1 Position X Inflection (boundary)
Y flange part (held part)

Claims (4)

A finder device that enables an optical image formed by a light beam that has passed through an objective lens to be observed through a finder optical system having an eyepiece,
A holding lens provided around an optical unit having an image forming action, and a final lens arranged on the most observation side among the eyepieces;
A first lens holding member having a protrusion that forms an opening that restricts a light beam incident on the final lens;
A second lens holding member that is disposed closer to the observation side than the first lens holding member, and holds the held portion of the final lens together with the first lens holding member;
Have
The final lens is
A boundary part for changing an inclination angle of an end face on the observation side with respect to the held part; and
A first end face that is located between the boundary portion and the held portion and is inclined away from the optical axis of the finder optical system from the boundary portion in a direction from the observation side toward the object side;
A second end face that is located closer to the observation side than the boundary part and is inclined in the direction away from the optical axis of the finder optical system;
Further comprising
In a cross section including the optical axis, an end portion of the projection of the first lens holding member that is closest to the optical axis is closer to the optical axis than the boundary portion, and the end portion is the second end surface. A finder device characterized in that an extended line extending from the position is closer to the optical axis than a position intersecting the protrusion.   2. The device according to claim 1, wherein the held portion has a flat surface on the object side, and the first lens holding member further has a flat surface that is positioned by being joined to the flat surface of the held portion. Finder device.   The held portion has a flat surface on the object side, the flat surface has a convex portion, and the first lens holding member further has a flat surface that is positioned by being joined to the convex portion of the held portion. The viewfinder device according to claim 1.   An imaging apparatus comprising the finder device according to claim 1.