JPH0990473A - Dust removing structure for finder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide dust removing structure for a finder capable of removing dust adhering to the optical parts of a finder in a state where a finder unit is assembled in a camera body by forming an air blow hole for removing dust on the case of the finder unit. SOLUTION: In a state where the finder unit 30 is assmebled in the camera body 33, the finder unit 30 is exposed except its base being a coupling part with the camera body 33. The air blow holes for removing the dust 44 and 71 are formed at the exposed part, that is, on the upper surface and the side surface of the unit 30, and its aperture part 30A on the base is covered by an adhesive tape 87. By making compressed air blow into the unit 30 from the holes 44 and 71, the dust adhering to the optical parts in the finder unit is scattered. The dust is stuck to the adhesive tape 87 and collected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for removing dust from a finder, and is particularly applied to compact cameras and the like.
The present invention relates to a finder dust removing structure suitable for removing dust adhering to a path of a finder optical system in a state where a finder unit is attached to a camera body.

[0002]

2. Description of the Related Art Conventionally, an optical finder incorporated in a camera is generally formed by housing optical components such as an objective lens, a prism, a field frame, and an eyepiece lens in a case of the finder, and the object light emitted from the objective lens. The prism is refracted to form a subject image, the field of view is regulated by a field frame, and the subject image is guided to an eyepiece lens so that the subject image can be observed through the eyepiece lens.

Further, in a compact camera, after the finder unit having the above-mentioned structure is assembled to the camera body, a process of attaching a front cover and a rear cover is performed. In such an assembling process, usually, after the finder unit is assembled to the camera body and before the cover is covered, the dust removal operation inside the finder unit is often performed. The dust removal work is performed by blowing gas (compressed air or the like) into the finder unit to scatter the dust.

[0004]

However, in the conventional viewfinder, there is a problem that the gas blown into the viewfinder unit does not reach the inside of the unit sufficiently and the effect of removing dust is weak. In particular, since the exit end surface of the prism, which is the image formation surface of the subject image, is enlarged by the eyepiece and guided to the eyepiece, it is necessary to reliably remove dust adhering to this image formation surface. Is not enough.

Further, such dust removal work is often performed in a process after the finder unit is assembled to the camera body and before the cover is assembled as described above, and the finder unit is disassembled for dust removal. Is not preferable in terms of work efficiency. The present invention has been made in view of the above circumstances, and provides a finder dust removing structure suitable for removing dust adhering to the path of the finder optical system in a state where the finder unit is assembled to the camera body. The purpose is to do.

[0006]

In order to achieve the above object, the present invention provides a finder dust removal for removing dust adhering to an optical component of a finder optical system housed in a case that can be incorporated in a camera body. In the structure, the case that houses the optical system of the finder,
It is characterized in that an opening through which gas can be blown from the gas blowing nozzle is provided in a portion exposed in the assembled state in the camera body.

According to the present invention, an opening through which a gas can be blown is formed in a case for housing a finder optical system in a portion exposed when the case is incorporated in the camera body. After the assembly, the gas can be blown from the opening to scatter the dust attached to the optical component. The opening may be formed at a position communicating with the vicinity of the image forming surface so as to remove dust adhering to a portion forming an image forming surface of a subject image among the optical components forming the finder optical system. Considered most effective.

By placing an adhesive tape on the bottom surface of the case, dust blown off by gas is attached to the adhesive tape. This can prevent dust from reattaching to the optical component.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of a dust removing structure for a finder according to the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a perspective view showing an appearance of a camera to which a dust removing structure for a finder according to the present invention is applied. At the center of the front surface of the front cover 11 of the camera 10 shown in FIG. A flash window 14 is formed at the upper right corner of the photographing lens 12, and a finder objective window 16, an AF projection window 18, a photometry window 20, and an AF light reception window 22 are sequentially formed on the left side of the flash window 14 in the drawing. ing. Also,
A shutter button 24 is provided on the upper surface of the camera 10.

An AF light projecting portion is provided inside the AF light projecting window 18, and an AF light receiving portion is provided inside the AF light receiving window 22. The distance between the light emitting / receiving portion and the object is measured. A distance unit is configured, and this distance measuring unit (AF unit) obtains the distance to the subject based on, for example, the principle of triangulation, and the result is used for autofocus (AF) control. Inside the photometric window 20, there is provided a lens (not shown) that allows external light to enter, and a photometric section composed of a light receiving element provided at the image forming position of the lens. To measure. The measurement result is the exposure control (A
It is used for E control).

The taking lens 12 is, for example, a 2 × zoom capable of changing the focal length in the range of f = 25 to 55 mm, or a 3 × zoom capable of changing the focal length in the range of f = 30 to 90 mm. In addition, each model is composed of a different optical system. A zoom button (not shown) is provided on the back surface of the camera 10. When this zoom button is operated, a lens driving motor (not shown) is driven, and the driving force of the motor is
It is transmitted to the drive mechanism of the photographing lens 12 and the drive mechanism of the moving lens drive system of the zoom finder. The photographer can select a desired photographing magnification by operating the zoom button, and can observe a field of view substantially equal to the photographing angle of view from the eyepiece of the viewfinder. The structure of the zoom finder and the drive mechanism of the moving lens drive system will be described later.

The taking lens 1 inside the camera 10
A shutter (not shown) is incorporated on the optical axis 2 and operates in conjunction with the operation of the shutter button 24. FIG. 2 is a perspective view of the finder unit 30 incorporated in the camera 10. In the main body case 31 of the finder unit 30, from the left in the figure, an AF light receiving housing 32 corresponding to the AF light receiving window 22, an AF light receiving housing 34 corresponding to the AF light emitting window 18, and the inside of the finder objective window 16 are provided. The objective lens 36 provided in the above is disposed.

In the finder unit 30, the main body case 31 is divided into a first storage case 40 and a second storage case 70 (see FIG. 3), and the first storage case 40 includes: The first block is formed by housing the AF section (AF light receiving section and AF light projecting section), the objective lens 36, the moving lens system 38, and the like. On the other hand, the second storage case 70 houses a prism 72, an eyepiece lens 74 and the like to form a second block.

FIG. 4 is an exploded perspective view of the first block. As shown in the figure, the first block is configured by mounting a finder variable magnification optical system and a drive mechanism of the variable magnification optical system in a first storage case 40. The viewfinder variable power optical system includes an objective lens 36 and moving lenses 42 and 43. The objective lens 36 is fitted in an objective lens opening window 40a formed in the front surface of the first storage case 40, and the movable lenses 42 and 43 are stored in a groove 45 behind the objective lens 36. To be done. A mask member 47 is provided between the movable lenses 42 and 43.

Flat portions 51 and 52 are formed on the left and right edges of the movable lenses 42 and 43, respectively, and projection portions 51A and 51A are integrally formed on the flat portions 51 and 51, and the flat portion 52 is formed. , 52 have guide holes 54, 5
5 are formed. A guide rod 56 is inserted through the guide holes 54 and 55, the front end of the guide rod 56 is press-fitted into a hole 40b formed in the front wall of the first storage case 40, and the rear end of the guide rod 56 is The first storage case 40
It is press-fitted and fixed in the hole 40b formed in the rear wall.

Further, in the first storage case 40, a step portion 57 is formed on the upper left side surface of the groove 45 for storing the movable lenses 42 and 43. This step 5
7, the protrusions 51A and 51A of the movable lenses 42 and 43
Is positioned, and the groove 45 is covered with the objective lid 41 from above the moving lenses 42 and 43, whereby a slide groove is formed by the step portion 57 and the lower edge of the objective lid 41. The movable lenses 42 and 43 are guided along the slide groove so as to be movable in the front-rear direction via the protrusions 51A and 51A, and the shake in the vertical direction is suppressed.

Follower pins 54A, 55A are protrudingly provided on the side portions of the movable lenses 42, 43.
A and 55A are engaged with a cam shaft 58 that constitutes a drive mechanism of the variable power optical system. The drive mechanism includes a cam shaft 58 and a motor (not shown) that rotationally drives the cam shaft 58. This motor is also used as a motor for driving the lens barrel 13 of the taking lens, and the rotational force of the motor is fixed to the cam shaft 58 via a gear train (not shown).
To be transmitted to.

The cam shaft 58 includes the moving lens 42,
Cam surfaces 58A and 58B that define the optical positional relationship of 43
Are formed on the outer periphery thereof. Both ends of the cam shaft 58 are press-fitted and fixed in holes 40c, 40c formed in the first storage case 40, respectively. The rear gear 59B
Is linked to a strobe mechanism (not shown). The driven pin 54A of the moving lens 42 contacts the front cam surface 58A of the cam shaft 58, and the driven pin 55A of the moving lens 43 contacts the rear cam surface 58B of the cam shaft 58. ing. In addition, L is provided above the moving lenses 42 and 43.
Character-shaped hooks 54B and 55B are formed, and a tension spring 48 is provided between these hooks 54B and 55B. Due to the biasing force of the tension spring 48, the driven pin 54A
Is pressed against the cam surface 58A, and the driven pin 55A is pressed against the cam surface 58B. This allows
The relative positions of the movable lenses 42 and 43 are regulated.

As described above, the motor for rotating the cam shaft 58 is also used as the motor for the lens barrel 13 of the taking lens. Therefore, when the motor is driven, the cam shaft 58 rotates in conjunction with the lens barrel 13. As a result, the shooting angle of view and the viewfinder visual field range match. Further, a long hole 44 is formed on the upper surface of the first storage case 40, that is, a portion where the guide rod 56 is to be mounted. The long hole 4
Reference numeral 4 communicates with an emission surface 72E of a prism 72, which will be described later, and blows compressed air (clean air) from a gas blowout nozzle (not shown) into the elongated hole 44 to collect dust attached to optical components inside the finder unit 30, particularly Dust adhering to the exit surface 72E of the prism described later can be scattered.

FIG. 5 is an exploded perspective view of the second block.
As shown in the figure, the second block is the second storage case 7
0, prism 72, high-definition (H) field frame 75,
Convention / Panorama (CP) field frame 76, field switching lever 79, field frame base 80, field lens 8
2, a mirror 83, an eyepiece lens 74, etc. are mounted.

The prism 72 has a second storage case 7
It is housed in the second storage case 70 along the inclined surface 70A formed on the upper part of 0, and is biased to the right side in the drawing by the prism pressing plate 73 to be positioned in the second storage case 70 without rattling. Has been done. The prism 72 has a shape in which two right-angle prisms are combined, and the incident subject light is reflected three times to obtain an erect image. That is, the subject light emitted from the zoom optical system enters from the incident surface 72A of the prism 72, is reflected downward by 90 degrees at the reflecting surface 72B, is then reflected forward by 90 degrees at the reflecting surface 72C, and is further reflected by the reflecting surface. The exit surface 72E is reflected by 72D in the horizontal direction (horizontal direction) by 90 degrees and is orthogonal to the entrance surface 72A.
Is emitted from. A target mark and a parallax correction mark are engraved on the emission surface 72E, and a subject image is formed on the emission surface 72E. As described above, the camera 72 is thinned by folding the optical path once in the incident direction (forward) by the prism 72.

The H field frame 75, which is disposed in the vicinity of the exit surface 72E of the prism, has a print aspect ratio (PA
It is a fixed frame that defines a field of view with an angle of view equivalent to the high definition size (H size) of R), and convention (C)
It is a visual field frame that defines the largest area including the size or the panorama (P) size. Behind the H visual field frame, there is further provided a CP visual field frame 76 capable of switching and defining visual fields corresponding to C size or P size. The CP visual field frame 76 is a pair of approximately L-shaped visual field frame pieces 76.
a, 76b, visual field switching lever 79, and visual field frame base 8
0, and the pair of field frame pieces 76a, 7
6b are vertically opposed to each other, and the pair of visual field frame pieces are moved toward or away from each other in the direction of 45 degrees to expand or contract the visual field area of C size or P size.

At both ends of the field frame pieces 76a and 76b, rectangular stroke holes 77 are formed in an oblique 45 degree direction.
A and 77B are formed. This stroke hole 77
Pins 80a and 80b protruding from the field frame base 80 are engaged with A and 77B. In addition, the field frame piece 76
Slots 78A and 78A are provided near the corners of a and 76b, respectively.
B is formed, and pins 79a and 79b projecting from the visual field switching lever 79 are engaged with the long holes 78A and 78B, respectively.

A circular arc guide groove for guiding the rotation of the visual field switching lever 79 is formed on the front surface of the visual field frame base 80, and the visual field switching lever 79 is rotated by being guided by the circular arc groove. As a result, the visual fields can be switched by the visual field frame pieces 76a and 76b. A field lens 82 is fixed behind the field frame base 80, and a mirror 83 is fixed behind it. The mirror 83 is fitted into the edge surface portion of the second storage case 70 at an angle of 45 degrees with respect to the exit surface of the field lens 82, and is biased from the rear of the mirror 83 by the mirror pressing plate 85 to generate the second light. It is fixed to the storage case 70. The optical axis of the exit surface of the prism 72 is reflected by the mirror 83 toward the back surface of the camera 10 by 90 degrees and guided to the eyepiece lens 74.

The eyepiece lens 74 is the second storage case 7
A diopter adjustment cam (not shown) is provided in the opening 70B formed in 0.
It is attached so as to be movable back and forth through. The diopter adjustment cam is connected to the diopter adjustment knob, and the photographer can adjust the diopter by moving the diopter adjustment knob to move the eyepiece lens 74 back and forth. On the other hand, a gear 79C is formed below the visual field switching lever 79, and the gear 79C is meshed with the switching gear 88A. Switching gear 88
A is formed at one end of the visual field switching shaft 88 shown in FIG.

FIG. 6 is a structural view of the visual field switching mechanism. As shown in the figure, this visual field switching mechanism is provided on the wall surface 11a at the rear of the camera so as to be movable up and down.
And the PAR knob 90, which is connected to the PAR knob 90.
And a PAR contact piece 91 that moves up and down together with the PA.
The CHP lever 93 is connected to the R contact piece 91 and is provided with a spring 92 for transmitting the vertical movement of the PAR contact piece 91 to the visual field switching shaft 88.

Inside the wall surface 11a behind the camera 10,
Click groove 9 for regulating the stop position of the PAR contact piece 91
5A, 95B, and 95C are formed, which correspond to the switching of the respective visual fields of C, H, and P from the top of the drawing. The PAR contact piece 91 has the click groove 95A,
A claw 91A that engages with one of 95B and 95C is formed by bending, and the PAR knob 90 includes the C, H, and
It can be switched to three stages of P.

As described above, one end of the visual field switching shaft 88 is connected to the gear 79C of the visual field switching lever 79 via the switching gear 88A, and the other end is connected to the CHP lever 93 via the CHP spring 92. As a result, PAR knob 9
When 0 is switched up and down, PAR contact piece 91 moves up and down, and CHP
The lever 93 moves up and down. The movement of the CHP lever 93 is transmitted to the visual field switching shaft 88 via the spring 92.

Since the C size or P size is a size in which the high-definition size region is partially limited, the pair of visual field frame pieces 76a and 76b is used while using the fixed frame of the H visual field frame 75. It is possible to switch the field of view corresponding to each size of H, C, or P by combining the above and below and moving both the field frame pieces 76a and 76b by an appropriate amount in the diagonal direction.

By the way, in order to assemble the second block shown in FIG. 5 below the first block shown in FIG. 4, the holes 40 formed in the first storage case 40 of the first block are assembled.
d and 40d, the protrusions 70d formed on the second block,
70d are respectively fitted and positioned, the holes 40e, 40e of the first block and the holes 70e, 70e of the second block are aligned, and they are connected from above by screws. As a result, the finder unit shown in FIG. 2 is obtained. The finder unit 30 is attached to the upper part of the camera body 33 through the hole 40f.

FIG. 7 is a rear view of the second storage case 70. As shown in FIG. 7, a hole 71 (opening) is formed on the back surface of the second storage case 70. The hole 71 is
It communicates with the vicinity of the exit surface 72E of the prism 72,
The long hole 4 formed in the first storage case 40 shown in FIG.
As in the case of 4, the compressed air can be blown from the hole 71 to scatter the dust in the finder unit 30, especially the dust adhering to the exit surface 72E of the prism.

FIG. 8 is a view for explaining the dust removing structure of the finder, which is a sectional view of the finder unit 30 taken along the emission surface 72E of the prism 72. still,
The left side of the figure corresponds to the front of the camera 10. As shown in the figure, the finder unit 30 is assembled on the upper part of the camera body 33, and in this state, the bottom surface of the finder unit 30 is an assembly surface with the camera body 33 and is exposed from the outside. Not not. Then, the front surface, the upper surface, the back surface, and both side surfaces of the finder unit 30 are exposed. In the present embodiment, holes 44 and 71, which are gas blowing ports for removing dust, are formed on the upper surface and the back surface of the exposed portion of the finder unit 30 that is assembled to the camera body 33. Is characterized by.

An opening 30A is formed on the bottom surface of the finder unit 30, and the opening 30A is closed by an adhesive tape 87. This adhesive tape 87
Is for adhering dust scattered by the compressed air introduced from the dust blowing gas blowing holes 44, 71. According to the finder configured as described above, as shown in FIG. 8, when the finder unit 30 is assembled to the camera body 33, the bottom surface of the finder unit 30 serves as a connecting portion with the camera body 33. It is hidden on the outside and the other parts are exposed. Since the dust removing holes 44 and 71 are provided on the exposed portion, that is, on the upper surface and the back surface of the finder unit 30, the gas blowing hole 44 for removing the dust is attached after the finder unit 30 is assembled to the camera body 33. , 71 to blow clean air to scatter dust adhering to the optical components in the finder unit 30.

Particularly, in the present embodiment, since the dust removing holes 44, 71 are formed at the positions communicating with the exit surface 72E of the prism, the dust adhering to the image forming surface of the subject image can be effectively treated. Can be removed. By changing the place where the hole is formed, it is possible to effectively remove the dust adhering to the portion other than the exit surface of the prism.

Further, since the adhesive tape 87 is provided on the bottom surface of the finder unit 30, the dust scattered by the clean air adheres to the adhesive tape 87. This can prevent reattachment of dust. After the dust removal work is completed, the front cover and the back cover of the camera are attached, and the assembly of the camera 10 is completed.

The subject light incident through the objective lens 36 is bent downward by the prism 72 as shown in FIG.
Further, it is bent in a direction orthogonal to the incident optical axis, that is, in the lateral direction of the camera 10, and an image is formed on the exit surface 72E of the prism. Then, the subject image formed on the exit surface 72E can be observed from the eyepiece through the field lens 82 and the eyepiece lens 74. The emission surface 72E is
Since the dust has been removed by the dust removal work described above, a good subject image can be observed from the eyepiece.

When the photographer operates the zoom switch to change the focal length of the photographic lens 12, the cam shaft 58 is rotated by the gear that rotates in conjunction with the focus variable mechanism of the photographic lens 12. (See FIG. 4), it is possible to form a subject image at the eyepiece of the finder that is substantially equal to the magnification scaled by the taking lens system. When the photographer operates the CHP knob 90 to select the desired aspect ratio, the CP visual field frame 76 is expanded or contracted as described above, and the visual field is switched.

In the above embodiment, the case where the gas blowing holes for removing dust are formed on the upper surface and the rear surface of the finder unit, respectively, is described. However, the holes are formed at other positions. Alternatively, the number of holes to be formed may be plural. In the above embodiment, the zoom finder capable of switching the field of view in three stages of CHP has been described. However, the optical components of the finder are irrespective of whether the field of view is switched or not. The present invention can be widely applied to those that form a finder unit by housing the.

[0039]

As described above, according to the dust removing structure of the finder of the present invention, the case for housing the finder optical system is provided with the opening through which the gas can be blown in the exposed portion in the assembled state. Therefore, after the case is assembled into the camera body, gas can be blown from the opening to remove dust attached to the optical component. As a result, it is possible to effectively scatter and remove the dust adhering to the path of the finder optical system, and to improve the efficiency of the dust removing operation in the camera assembly process.

Further, since the adhesive tape is arranged on the bottom surface of the case to adhere the scattered dust, it is possible to prevent the scattered dust from re-adhering to the optical component.

[Brief description of drawings]

FIG. 1 is a perspective view showing an appearance of a camera to which a dust removing structure of a finder according to the present invention is applied.

FIG. 2 is a perspective view of a finder unit 30 incorporated in the camera 10.

FIG. 3 is a perspective view of a first block and a second block of the finder unit 30.

FIG. 4 is an exploded perspective view of a first block of the finder unit 30.

FIG. 5 is an exploded perspective view of a second block of the finder unit 30.

FIG. 6 is a structural diagram of a viewfinder field switching mechanism.

FIG. 7 is a rear view of the second block.

FIG. 8 is a sectional view for explaining the dust removing structure of the finder.

[Explanation of symbols]

 10 ... Camera 30 ... Finder unit 31 ... Main body case 33 ... Camera body 36 ... Objective lens 40 ... First storage case 42, 43 ... Moving lens 44 ... Slot 70 ... Second storage case 71 ... Hole 72 ... Prism

Claims (2)

[Claims] 1. A dust removing structure of a finder for removing dust adhering to an optical component of a finder optical system housed in a case that can be incorporated in a camera body, wherein a case for housing the finder optical system includes: An opening that can blow gas from the gas blowing nozzle,
A structure for removing dust from a finder, which is provided in a portion exposed in the camera body in an assembled state. 2. The dust removing structure for a finder according to claim 1, wherein an adhesive tape to which dust blown off by the gas is attached is arranged on a bottom surface of the case.