JP2003156781A - Field switching mechanism for finder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a field switching mechanism used in the finder of a camera and realizing space saving. SOLUTION: A field lens 23 and a roof prism 24 are provided to put an image-formation surface 27 in between, and masks 43 and 44 switching field are provided between the lens 23 and the prism 24. In a real image type finder, the emitting surface of the lens 23 is made smaller than the incident surface of the prism 24, so that the lens 23 is made shorter than the prism 24 in height. A guiding part for a mask driving member 40 is provided in space above the lens 23 formed by making the lens 23 shorter in height. The guiding part is constituted of a guide boss 60 formed on the lens 23 and the part where the guide groove 61 is formed of the member 40.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a visual field switching mechanism such as a viewfinder of a camera.

[0002]

2. Description of the Related Art Conventionally, many visual field switching mechanisms have been proposed. For example, in the visual field switching mechanism disclosed in Japanese Patent Laid-Open No. 6-250281, a line spring is used for transmitting the driving force to achieve a space-saving visual field switching mechanism.

[0003]

However, since the wire spring is passed through the narrow groove, it is difficult to assemble the wire spring. Further, since the mask is driven by using a thin wire spring, there arises a problem in strength of the mask made of thin resin or the like.

An object of the present invention is to provide a space-saving field-of-view switching mechanism used in a camera finder or the like.

[0005]

In order to achieve the above object, a viewfinder switching mechanism of a finder according to a first aspect of the invention has a first optical element provided in the vicinity of an image forming surface and a first optical element in the vicinity of the first optical element. A light blocking member which is provided and is capable of switching between a first field of view and a second field of view having a size different from that of the first field of view, and a drive for driving the light blocking member for switching between the first field of view and the second field of view And a member, and the first optical element has at least a part of a guide portion that guides the movement of the driving member.
The viewfinder switching mechanism of the finder according to claim 2 is provided in the vicinity of the first optical element provided in the vicinity of the image plane and in the vicinity of the image plane opposite to the first optical element with the image plane interposed therebetween. , A second optical element that receives the light flux from the first optical element, and is provided between the first optical element and the second optical element, and the first visual field and the first visual field have a size. A light-shielding member that can switch to a second field of view different from each other, and a drive member that drives the light-blocking member to switch between the first field of view and the second field of view.
Is formed smaller than the second optical element in the direction perpendicular to the optical axis, and a guide portion for guiding the movement of the driving member is provided between the second optical element and the optical axis of the first optical element. It is provided in a space caused by a difference in size in the vertical direction. A viewfinder switching mechanism of a finder according to claim 3, wherein a roof prism provided in the vicinity of the image forming surface, a housing for housing the roof prism, and a housing provided near the image forming surface and in the vicinity of the roof prism, the first view and the first view are provided. And a light blocking member capable of switching to a second field of view having different sizes, and
And a drive mechanism for driving the light blocking member for switching between the second visual field and the second visual field, and at least a part of the drive mechanism is provided in the space between the roof surface of the roof prism and the housing. The field-of-view switching mechanism of the finder according to claim 4, wherein a field lens having an image forming surface on the exit surface side, a prism provided on the side opposite to the field lens with the image forming surface interposed therebetween, the field lens and the prism. And a light blocking member for switching between the first field of view and the second field of view having a size different from that of the first field of view, and a light blocking member for switching between the first field of view and the second field of view. The field lens is formed to be smaller than the prism in the direction perpendicular to the optical axis, and is generated around the field lens due to the size difference between the field lens and the prism in the direction perpendicular to the optical axis. A guide portion for guiding the movement of the drive member is provided in the space. The field-of-view switching mechanism of the finder according to claim 5 is: a field lens having an image plane on the exit surface side; a first member attached to the field lens so as to form a predetermined gap with the field lens; The first member is inserted into a predetermined gap while being positioned in the direction perpendicular to the optical axis of the field lens, and can be switched between the first field of view and the second field of view having a different size from the first field of view. The field lens includes a light blocking member and a drive member that drives the light blocking member to switch between the first visual field and the second visual field. The field lens guides the movement of the driving member and moves in the optical axis direction of the moving member with respect to the field lens. A guide for positioning and a position used for mounting the field lens in the housing and for the optical axis direction and the direction perpendicular to the optical axis. And it has a positioning portion which is also used to decide. A camera according to a sixth aspect includes a finder optical system having the viewfinder field switching mechanism according to any one of the first to fifth aspects.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an overall view of a camera equipped with a visual field switching mechanism of a real image type finder according to the present invention. Figure 1
1A is a rear view of the camera seen from the rear, FIG. 1B is a top view of the camera seen from above, and FIG. 1C is a front view of the camera seen from the front. In FIG. 1C, the camera is shown in an upright state, but in the rear view of FIG. 1A, it is shown in an inverted state.

In FIG. 1, a camera 1 includes a taking lens 2, a shutter release button 3, a power switch 4, a zoom switch 5, an LCD display section 6, a strobe 7, and an AF.
(Auto focus) window 8, AE (auto exposure) window 9,
It has a case back 10. Further, reference numeral 11 in FIG. 1C is a finder objective window, and reference numeral 12 in FIG. 1A is a finder eyepiece window. A field frame switching lever 14 is provided on the left side of the finder eyepiece section 13 in the figure, and a diopter adjustment dial 15 is provided on the right side thereof. The strobe 7 is a retractable type strobe, which stands up as shown in FIG. 1C when used and is housed so as to have a shape conforming to the external appearance of the camera when not used (FIG. 2).

FIG. 2 shows a cross section of the finder optical system of the camera 1. The left and right of the figure correspond to the left and right of the camera,
The upper side of the figure corresponds to the photographer side, that is, the eyepiece side, and the lower side of the figure corresponds to the subject side, that is, the object side. The finder optical system includes an objective lens group 21, a mirror 22, a field lens 23, a roof prism 24, a prism 25, and an eyepiece lens 26 from the subject side. A surface of the field lens 23 on the roof prism 24 side is set as an image forming surface 27. Reference numeral 28
Is an AE light receiving unit, and includes an AE light receiving lens 29, an infrared cut filter 30, and an AE light receiving element 31. Code 32
Is an urging spring that urges the mirror 22 to be fixed at a predetermined position. Reference numeral 33 is a finder housing. An alternate long and short dash line 34 indicates the optical axis of the finder optical system.

Field lens 23 and roof prism 24
A field-of-view switching mechanism is provided near the boundary between and. The visual field switching mechanism includes the mask driving member 40 and the switching mechanism base 4.
1, a field frame 42, masks 43 and 44, and the like. The visual field switching mechanism is a visual field frame switching lever 1 by the photographer.
The view frame of the finder is switched between the normal frame and the panorama frame by the slide operation of 4 (FIG. 1). When the normal frame is selected, the field of view of the finder is defined as a normal screen size (full size), and when the panoramic frame is selected, the field of view of the finder is defined as a panoramic screen size (panorama size).

FIG. 3 is a perspective view of the vicinity of the visual field switching mechanism of this embodiment. Reference numerals are given corresponding to the components described in FIG. Spring hooking part 4 of mask driving member 40
The mask driving member biasing spring 46 is applied between the spring 5 and the spring hooking portion 100 (FIG. 10) of the finder housing 33, and the mask driving member 40 is biased in the arrow 47 direction by the spring force. Reference numerals 48 and 49 are interlocking levers described later. The objective lens group 21 includes movable lenses 21a and 21b that move during zooming, and a fixed lens 21c.

FIG. 4 is a diagram showing the components of the visual field switching mechanism. FIG. 5 is a view showing a state (assembly, subassembly) in which the components shown in FIG. 4 are assembled. The assembly in the state of FIG. 5 is incorporated in the finder housing 33, and the mask drive member biasing spring 46 is applied between the spring hooking portion 45 of the mask drive member 40 and the spring hooking portion 100 (FIG. 10) of the finder housing 33. The mask driving member 40 is biased in the direction of arrow 47.

In FIG. 6, the field lens 23 is used to form the image plane 2.
It is the perspective view seen from 7 side (exit surface side). A guide boss 60 is provided on the upper surface of the field lens 23 and is inserted into and engaged with the guide groove 61 of the mask driving member 40 (FIGS. 3 and 4). In addition, the groove 6 of the finder housing 33
Flanges 62, 63, 64 are provided that are press-fitted into 5, 66 (Fig. 2), 73 (Fig. 9). Flange 62, 6
The field lenses 23 are positioned in the direction of the optical axis 34 by press-fitting the grooves 3, 64 into the grooves 65, 66, 73. Positioning of the field lens 23 in the vertical direction of the camera is performed by pressing the lower surface 67 of the field lens 23 into contact with the housing. A target mark 68 is provided on the imaging surface (emission surface) 27. Reference numeral 74 is the rest of the gate.

FIG. 7 is a view showing the switching mechanism base 41. The switching mechanism base 41 is provided on the flanges 62 and 63 of FIG.
Bosses 69 and 70 that are press-fitted into the holes 80 and 81 are provided, and the switching mechanism base 41 is press-fitted until it comes into contact with the base receiving surfaces 71 and 72. The positions of the base receiving surfaces 71 and 72 are such that when the switching mechanism base 41 contacts, the field frame 23 and the masks 43 and 44 are located between the field lens 23 and the switching mechanism base 41.
It is set so that there is a gap where and can be placed.

On the switching mechanism base 41, a mask guide boss 82 inserted into and engaged with the mask guide groove 84 of the mask 43 and the mask guide groove 85 of the mask 44, and the mask 44.
Mask guide groove 86 of the mask, the mask guide groove 8 of the mask 44
7 and a mask guide boss 83 which is inserted into and engages with each other (FIGS. 4 and 7). The movement of the masks 43 and 44 in the vertical direction of the camera is guided by the mask guide bosses 82 and 83 and the mask guide grooves 84 to 87. The switching mechanism base 41 is provided with a groove 88 into which the mask driving boss 90 (FIG. 8) provided on the mask driving member 40 is inserted. By inserting the mask drive boss 90 into the groove 88 of the switching mechanism base 41, the position of the mask drive member 40 in the vertical direction of the camera is defined.

FIG. 8 is a diagram showing the relationship between the mask driving member 40 and the field lens 23. Field lens 2
The guide groove 61 of the mask driving member 40 is engaged with the guide boss 60 on the upper surface of the third face 3, and the interlocking boss 91 is inserted into the interlocking boss guide groove 101 (FIG. 10) of the finder housing 33. As a result, the mask driving member 40 is positioned in the direction of the optical axis 34, and the driving in the direction of the arrow 92 when switching the field frame is guided.

Next, the principle will be described before the description of FIG. Generally, the effective diameter of the prism used in the eyepiece optical system of the real image finder is smaller on the incident surface side than on the exit surface side. Therefore, for example, in a finder optical system of a type in which a roof prism and a prism are combined to bend the optical axis in a plane, the effective diameter of the entrance side of the roof prism, which is closer to the imaging surface, is smaller than the effective diameter of the exit surface of the prism on the eyepiece side. The smaller one. By utilizing this fact, the height of the field lens provided near the image plane can be made smaller than the height of the roof prism.

FIG. 9 is a view showing a longitudinal section of the field lens 23, the visual field switching mechanism, and the roof prism 24 in the vicinity of the optical axis 34. In the present embodiment, based on the above-mentioned contents, the field lens 2 is more than the height of the roof prism 24.
The height of 3 is designed low. That is, the exit surface of the field lens 23 is designed to be smaller than the entrance surface of the roof prism 24. And the roof prism 24
The guide portion of the mask driving member 40 is provided in the space created by the height difference between the field lens 23 and the field lens 23. The guide portion of the mask driving member 40 is configured by the portion of the mask driving member 40 where the guide groove 61 is formed and the guide boss 60 of the field lens 23.

FIG. 10 is a diagram for explaining how the mask driving member 40 is driven. The mask driving member 40 is urged in the direction of arrow 47 by a mask driving member urging spring 46 hung between the spring hooking portion 100 of the finder housing 33 and the spring hooking portion 45 of the mask driving member 40. The interlocking boss 91 is in contact with the interlocking lever 49. Therefore, the mask driving member 40 tries to rotate counterclockwise around the mask driving boss 90, but when the mask driving member 40 rotates a small amount, the curved surface 102 hits the finder cover 103 and the rotation stops.

When the interlocking lever 49 is driven in the direction of arrow 112 (described later), the mask drive member 40 is driven in the direction of arrow 112 against the spring force of the mask drive member biasing spring 46. When the mask driving member 40 is driven in the direction of arrow 112, the mask driving boss 90 drives the masks 43 and 44 in the vertical direction of the camera.

FIG. 11 is a diagram showing the relationship among the mask driving member 40, the masks 43 and 44, and the field frame 42. In the state of FIG. 11, the masks 43 and 44 are in positions retracted from the visual field, and the normal frame defined by the visual field frame 42 is selected. Cam (groove) 104 on the mask 43
And a cam (groove) 105 is formed in the mask 44, and the mask driving boss 90 is inserted and engaged with each other.

When the interlocking lever 49 is driven and the mask driving member 40 is driven in the direction of the arrow 112, the mask driving boss 90 pushes the cams 104 and 105, and the mask 43.
Moves up and the mask 44 moves down. The mask guide bosses 82 of the switching mechanism base 41 are inserted and engaged in the mask guide grooves 84 and 85, and the mask guide bosses 83 are inserted and engaged in the mask guide grooves 86 and 87 to guide the vertical movement of the masks 43 and 44. FIG. 12 is a diagram showing a state in which the panorama frame is switched to.

FIG. 13 shows an interlocking lever 49 for switching the field frame.
It is a figure explaining the movement of. The interlocking lever 49 is provided inside the finder housing 33, and the interlocking lever 48 shown by a broken line is provided outside the finder housing 33. The interlocking lever 48 and the interlocking lever 49 are fixed to each other by the screw 106 through the hole of the finder housing 33 and rotate in conjunction with each other.

When the photographer operates the field frame switching lever 14 (FIG. 1) provided outside the camera, the operation amount is transmitted to the interlocking lever 48 by a coupling mechanism (not shown). A broken line interlocking lever 48 and a solid line interlocking lever 49 in FIG.
Indicates that the normal frame is selected. When the panorama frame is selected in this state, the operation amount of the field frame switching lever 14 is transmitted to the interlocking lever 48 in the direction of the arrow 107, and the interlocking lever 48 rotates to the two-dot chain line state. Interlocking lever 4
9 also rotates in conjunction with the two-dot chain line.

The interlocking boss 91 is in contact with the interlocking lever 49 by the mask driving member biasing spring 46, and the interlocking boss 9 is accompanied by the panorama frame switching operation of the field frame switching lever 14.
1 is driven along the interlocking boss guide groove 101 to the state of the chain double-dashed line. When the interlocking boss 91 is driven, the mask driving member 40 moves, and the field frame is switched as described above.

FIG. 14 is a view showing a vertical cross section of the mounting portion of the interlocking levers 48, 49. FIG. 3 is a vertical sectional view taken along the vicinity of an optical axis 108 of the AE light receiving unit 28 in FIG. 2. The roof prism 24 has roof surfaces 109 and 110 (see FIG. 3). In the space 111 formed in the lower part of the roof surface 109, the interlocking lever 48 and the interlocking lever 49 are attached with screws 106.
Is used to rotatably fix the finder housing 33. That is, the interlocking lever mechanism is provided in the space below the roof surface 109 of the roof prism 24.

As described above, in the present embodiment, the guide portion of the visual field switching mechanism is provided in the space formed above the field lens 23 due to the height difference between the roof prism 24 and the field lens 23. As a result, a space-saving visual field switching mechanism can be achieved. Further, the guide boss 60 of the field lens 23 and the guide groove 61 of the mask driving member 40, which constitute the guide portion, can be engaged with each other by a sufficiently thick member and a sufficiently wide groove, which causes a problem in strength. Nor. Further, the portion of the mask driving member 40 where the guide groove 61 is provided has a width corresponding to the thickness of the field lens 23, and can have a thickness corresponding to the space generated by the height difference between the roof prism 24 and the field lens 23. Becomes Thereby, the mask driving member 40
The strength of the guide portion can be secured, and the mask driving member 40 can be stably slid.

Further, in this embodiment, the field lens 23 has the guide boss 60 formed on the upper surface of the field lens 23. That is, the field lens 23 is
It has at least a part of a guide portion for guiding the mask driving member 40. Further, in the field lens 23, the lens portion, the guide boss 60, the flanges 62 to 64, the bosses 69, 70, etc. are integrally formed of the same resin material. With these, it is possible to achieve a small-sized mechanism with high dimensional accuracy.

Further, in this embodiment, the interlocking lever 49
Is provided in the finder housing 33, and the interlocking lever 48
Are provided outside the finder housing 33, and they are fixed with screws through the holes of the finder housing 33 so as to rotate integrally. As a result, it is possible to prevent dust and dirt from entering the finder housing 33, and to prevent dust and dirt from adhering to the imaging surface 27. In the downsized real image type viewfinder, the magnifying power of the eyepiece optical system is increased, so that dust and dirt on the image forming surface are easily visible. However, this can be prevented in the viewfinder using the visual field switching mechanism of the present embodiment.

Further, in the present embodiment, the interlocking lever 4 which is a part of the driving mechanism of the masks 43 and 44 which are light shielding members.
8, 49 and the like are provided in the space below the roof surface 109 of the roof prism 24. As a result, the roof 1
You can effectively use the dead space under 09,
Further space saving of the visual field switching mechanism is realized. Further, a part of the screw 106 and the interlocking lever 49 are provided on the roof surface 10
The dead space between 9 and the finder housing 33 that houses the roof prism 24 is effectively used.

Further, the roof surface 109 extends to the vicinity where the mask driving member 40 is provided (FIG. 3). Therefore, the interlocking levers 48 and 49, which are rotating members for driving the mask driving member 40, can be arranged at the lower part of the roof surface 109 and the rotation center can be brought to a position close to the mask driving member 40. As a result, the interlocking lever 48,
The field-of-view switching mechanism including 49 can be designed small and compact.

Further, in the present embodiment, the switching mechanism base 41, the masks 43, 4 are provided for the field lens 23.
4, the field frame 42, and the mask driving member 40 are attached and positioned. Then, in the assembled state as shown in FIG. 5, the flange 62 of the field lens 23,
63 and 64 are used to mount and position the viewfinder housing 33. That is, the switching mechanism base 4
1, masks 43 and 44, field frame 42, mask driving member 4
The field switching mechanism such as 0 is positioned with the field lens 23 as a reference. As a result, accurate positioning and easy manufacturing can be realized.

In the above embodiment, the guide portion of the mask driving member 40 is connected to the guide boss 6 of the field lens 23.
0 and the portion of the mask driving member 40 where the guide groove 61 is formed have been described, but the present invention is not necessarily limited to this. A boss may be formed on the mask driving member 40 side and a groove may be formed on the field lens 23 side. That is, any guide portion may be used as long as it is provided using the space created by the height difference between the roof prism 24 and the field lens 23.

Further, in the above embodiment, an example of utilizing the space generated above the field lens 23 has been described, but the present invention is not necessarily limited to this. You may make it utilize the space produced in the side surface, the lower part, etc. of the field lens 23. That is, the roof prism 24
Any one may be used as long as it uses the space generated around the field lens 23 due to the difference in size in the direction perpendicular to the optical axis of the field lens 23.

Further, in the above embodiment, the example of the 35 mm film camera has been described, but it is not necessarily limited to this content. For example, it can be applied to an APS camera that switches the screen size to C size, H size, and P size. Further, the screen size may be switched differently from these.

In the above embodiment, an example of a still camera using a film has been described, but it is not necessarily limited to the contents. For example, it may be an electronic camera. It can also be applied to a video camera that captures moving images. Further, it may be another optical device (product). That is, the present invention can be applied to all optical devices (products) equipped with a finder having a visual field switching mechanism.

[0036]

Since the present invention is configured as described above, it has the following effects. A space-saving field-of-view switching mechanism can be realized by effectively utilizing an optical element near the image plane, for example, a space generated above the field lens.

[Brief description of drawings]

FIG. 1 is a diagram showing an overall view of a camera equipped with a visual field switching mechanism of a real image type finder of the present invention.

FIG. 2 is a view showing a cross section of a viewfinder optical system of a camera.

FIG. 3 is a perspective view of the vicinity of a visual field switching mechanism according to the present embodiment.

FIG. 4 is a diagram showing components of a visual field switching mechanism.

5 is a diagram showing a state in which the components shown in FIG. 4 are assembled.

FIG. 6 is a perspective view of the field lens seen from the image plane side (emission side).

FIG. 7 is a view showing a switching mechanism base.

FIG. 8 is a diagram showing a relationship between a mask driving member and a field lens.

FIG. 9 is a view showing a vertical section in the vicinity of the optical axis of a field lens, a visual field switching mechanism, and a roof prism.

FIG. 10 is a diagram illustrating how the mask driving member is driven.

FIG. 11 is a diagram showing a relationship between a mask driving member, a mask, and a field frame.

FIG. 12 is a diagram showing a state in which the panorama frame is switched to.

FIG. 13 is a diagram for explaining the movement of the interlocking lever when switching the field frame.

FIG. 14 is a view showing a vertical cross section of a mounting portion of an interlocking lever.

[Explanation of symbols]

2 Shooting lens 14 Field-of-view frame switching lever 23 Field lens 24 Dach Prism 25 prism 26 eyepiece 27 Image plane 33 Finder housing 40 Mask driving member 41 Switching mechanism base 42 view frame 43,44 mask 48, 49 interlocking lever 60 Guide boss 61 Guide groove 62-64 flange 90 Mask driven boss 91 Interlocking boss 104, 105 cam 109, 110 Dach side

Claims (6)

[Claims] 1. A first optical element provided near an image plane, and a second visual field provided near the first optical element, the first visual field and the first visual field having different sizes. And a driving member that drives the light blocking member to switch between the first visual field and the second visual field, and the first optical element is configured to move the driving member. A viewfinder switching mechanism for a finder, which has at least a part of a guiding portion for guiding. 2. A first optical element provided in the vicinity of the image plane, and a first optical element provided in the vicinity of the image plane opposite to the first optical element with the image plane interposed therebetween. It is provided between a second optical element that enters a light beam from an optical element and the first optical element and the second optical element, and the first visual field and the first visual field have different sizes. A light-shielding member that can be switched to a second field of view; and a drive member that drives the light-blocking member to switch between the first field of view and the second field of view, wherein the first optical element has an optical axis A guide portion that is formed smaller than the second optical element in a direction perpendicular to the second optical element, and that guides the movement of the drive member in a direction perpendicular to the optical axes of the second optical element and the first optical element. Viewfinder switching, characterized by being provided in a space caused by the difference in size Structure. 3. A roof prism provided near an image forming surface, a housing for housing the roof prism, and a housing provided near the image forming surface and near the roof prism.
And a second light field having a size different from that of the first field of view, and a drive mechanism for driving the light blocking member to switch between the first field of view and the second field of view. A field-of-view switching mechanism for a finder, wherein at least a part of the drive mechanism is provided in a space between a roof surface of the roof prism and the housing. 4. A field lens having an image forming surface on the exit surface side, a prism provided on the opposite side of the field lens with the image forming surface interposed, and between the field lens and the prism. A first field of view and a second field of size different from the first field of view
And a drive member that drives the light blocking member to switch between the first field of view and the second field of view, and the field lens with respect to a direction perpendicular to the optical axis. ,
A guide portion that is formed smaller than the prism and that guides the movement of the driving member is provided in a space generated around the field lens due to a difference in size between the field lens and the prism in a direction perpendicular to the optical axis. A viewfinder switching mechanism that is characterized in that 5. A field lens having an image plane on the exit surface side, a first member attached to the field lens so as to form a predetermined gap with the field lens, the field lens and the first lens. The member is inserted into the predetermined gap while being positioned in the direction perpendicular to the optical axis of the field lens, and can be switched between the first field of view and the second field of view having a different size from the first field of view. A light blocking member; and a driving member that drives the light blocking member to switch between the first visual field and the second visual field, wherein the field lens guides the movement of the driving member and the moving member A guide portion for positioning the field lens in the optical axis direction, and a guide portion used for attaching the field lens to the housing and A field-of-view switching mechanism for a finder, which has a positioning section that is also used for positioning in the optical axis direction and a direction perpendicular to the optical axis. 6. A camera comprising a finder optical system having a viewfinder switching mechanism according to claim 1. Description: