JP2001013548A - Camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide optical equipment which is constituted so that dust arising in a closed space formed between optical parts can be easily removed. SOLUTION: A focusing screen 5, a visual field mask 9, a condenser lens 11 and a pentagonal prism 13 are successively arranged in each prescribed position on a mirror box 2. The closed space 27 is formed between the condenser lens 11 and the pentagonal prism 13, and two grooves 20c and 20d formed in a part of the mirror box 2 communicate with the closed space 27, and holes 20a and 20b are formed so as to pass through the wall of the mirror box 2 while communicating with the two grooves. Besides, an air flow direction changing member 28 for changing the flowing direction of the guided air is arranged with a prescribed inclination near one of the paths formed by the grooves 20c and 20d and the holes 20a and 20b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical apparatus, and more particularly to an optical apparatus optimally used for a camera having a finder optical system.

[0002]

2. Description of the Related Art In a camera, which is one type of optical equipment, dust easily adheres to an optical component constituting the finder optical system, and the dust attached to an optical component relatively close to the focal plane is more noticeable. In the camera, dust adhering to the exposed surface of the optical component can be removed by blowing it off with a blower or the like or wiping it with a solvent or the like (anhydrous alcohol or the like). However, dust that has entered the closed (closed) space of the viewfinder optical system consisting of multiple optical components cannot be easily removed, and the only method is to disassemble the optical system and remove the attached dust. Did not.

[0003] As means for solving this problem, for example,
Japanese Patent Application Laid-Open No. Hei 8-2111453 discloses a closed finder optical system for preventing dust from entering the inside. In the finder optical system having such a configuration, the assembling is performed in a clean room or the like in order to prevent the invasion of dust from the outside after the assembling.

Further, as a technique for easily removing dust entering a closed space constituted by a plurality of optical components of a finder optical system, a plurality of passages for communicating the closed space with the inside and outside of the device are formed. A technology has been proposed in which air is allowed to flow into a closed space to blow off dust, and the dust is discharged from the other passage. This configuration will be described below.

FIG. 7 is a plan view showing a main part of a conventional optical apparatus. Here, a single-lens reflex camera is used as an example of the optical apparatus. 7A is a sectional view of a finder optical system of a camera, and FIG. 7B is a sectional view of FIG.
FIG. 3 is a plan view of the viewfinder optical system in a closed space.

The finder optical system includes a focusing screen 5, a field mask 9, a condenser lens 11 disposed above the focusing screen 5, a pentaprism 13 disposed above the condenser lens 11 via a spacer 12, and a pentaprism 13. Air inlet and outlet holes 20a, 2 formed along the side surface of the pentaprism 13.
0b and a closed space 27 formed between the condenser lens 11 and the pentaprism 13 so as to communicate with the holes 20a and 20b. 2 is a mirror box.

A discharge port of a nozzle A such as an air compressor is disposed opposite to the air inflow hole 20a. When air is sent from the nozzle A to the hole 20a, a U-shape is formed from the hole 20a to the hole 20b. It flows along the wall surface of the spacer 12 in the closed space 27 and is discharged from the hole 20b.

[0008]

However, in the configuration disclosed in Japanese Patent Application Laid-Open No. Hei 8-212453, the components are often assembled with dust attached to a part of the components, or the dust is peeled off after the assembly is completed. Adhering to the viewfinder field of view and long-term use,
In some cases, the coating applied to the optical component for the purpose of measures against internal reflection or the like is peeled off and adheres to the optical surface in the visual field of the sealed finder optical system. In this case, the only way to remove dust is to disassemble the sealed finder optical system components and remove the dust.This requires rework during the assembly process at the factory and reassembly and cleaning in the service. It takes a lot of time and effort.

Further, in the configuration shown in FIG. 7, there is no need to rework the sealed finder optical system to remove dust by removing the components.
Is convex toward the center of the optical axis, so that there is a problem that it is difficult to remove dust at the center.

[0010] An object of the present invention is to provide an optical apparatus capable of easily removing dust generated in a closed space formed between optical components.

[0011]

According to a first aspect of the present invention, there is provided a configuration including a plurality of optical components forming an optical path, wherein dust or the like is present in the optical path. In a viewfinder optical system of a camera, which has an undesired closed space provided between the plurality of optical components, an air inlet hole communicating the closed space with the outside of the machine, and an air outlet hole, The camera has an air flow direction changing member provided with a predetermined angle outside the visual field range in the extension direction of the hole.

According to this configuration, when air is supplied into the closed space from one of the plurality of passages provided in the holding member, the air flow flowing into the closed space forms a predetermined angle outside the viewfinder viewing range. The air flow direction changing member provided directs the optical component to a portion where the attachment of dust or the like is undesirable. As a result, dust or the like adhering to the optical component is peeled off, and is discharged to the outside of the apparatus from the other side of the passage together with the airflow. Therefore, dust generated in the closed space formed between the optical components can be easily removed.

Further, in a camera which is a precision optical device, by providing an air flow direction changing member outside the viewable range of the viewfinder optical system for which a viewable range needs to be secured, the adhesion of dust and the like is easily noticeable. An air flow can be formed towards the center of the system. Therefore, dust generated in the closed space formed between the optical components can be easily removed without obstructing the viewfinder view.

In a specific configuration for realizing the object of the invention according to the present application, the air flow direction changing member is provided near the outlet of the passage on the air supply side. An optical device characterized in that:

According to this configuration, the air flow direction changing member is provided near the outlet on the air supply side of the passage.
The air flowing into the enclosed space is changed in flow in a desired direction. Therefore, it is possible to form an airflow toward a portion where dust or the like is likely to adhere or a portion where dust or the like is not desirable.

According to a specific configuration for realizing the object of the invention according to the present application, as set forth in claim 3, the plurality of passages provided in the holding member are configured such that communication with the outside of the machine is performed by an exterior member. The optical device is characterized by being sealed using the optical device.

According to this configuration, if the plurality of passages provided in the holding member are always open, dust and the like can easily enter the closed space from the outside. Therefore, the entrance of the passage is sealed with an exterior member so that it can be opened only when necessary. This prevents dust and the like from entering the passage and the closed space from the outside.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing the overall structure of the camera. FIG. 2 is a perspective view showing details of a finder optical system and a mirror box of FIG. In FIG. 1, reference numeral 1 denotes a camera body, and 2 denotes a mirror box having a built-in quick mirror (not shown), which serves as a base of a finder optical system fixed to the camera body. Reference numeral 3 denotes a lens mount, which is fixed to the opening of the mirror box 2 and has an interchangeable lens (not shown). Reference numeral 4 denotes a mirror unit, which is rotatably attached to the mirror box 2. 5 is an exchangeable focusing screen,
The light incident surface has a Fresnel lens 5a, and the light exit surface has a matt surface 5b. Reference numeral 6 denotes a holding frame, which is rotatably supported by the mirror box 2 and on which the focusing screen 5 is exchangeably mounted. The holding frame 6 includes a leaf spring 6a for pressing the focusing screen 5 against the surface of the mirror box 2 serving as a reference for focusing, and a hook 6b.
It has.

Reference numeral 7 denotes an engaging member formed by a leaf spring, which is engaged with the hook 6b of the holding frame 6, and
Is set at a predetermined position. By pulling the engaging member 7 in the rebound direction, the holding frame 6 is released from a predetermined position.
In this state, the focusing screen 5 can be attached to and detached from the holding frame 6. Reference numeral 8 denotes the mirror box 2 that covers the holding frame 6 and the engagement member 7 inside the lens mount 3.
The cover is fixed to the cover. Reference numeral 9 denotes a visual field mask having an opening, which defines a boundary of a screen in a finder visual field. 11 is a condenser lens, 12 is a spacer provided above the periphery of the condenser lens, and 13 is a spacer 1
It is a pentaprism attached so that 2 contacts. Portions of the pentaprism 13 other than the light incident surface 13a and the light exit surface 13b of the finder optical system are coated with black to prevent internal reflection. 14
Is a penta cover that covers the penta prism 13.

As shown in FIG. 2, the spring member 15 has a hook 14a provided at two places on the left and right of the cover 14 and a hook 2i and a hole 2j provided at two places on the left and right of the mirror box 2. It is hung, and the penta cover 14 is brought into close contact with the penta prism 13. 16a and 16b are eyepieces, and 17 is a protective glass. These constitute a finder optical system together with the focusing screen 5, the condenser lens 11, and the pentaprism 13.

In FIG. 1, reference numeral 20 denotes a pair of holes, which comprises an air inflow hole 20a and a discharge hole 20b formed in two flat portions 2f of the mirror box 2. Hole 20
The hole 20a communicates with the closed space 27 of the finder optical system. 21 is a known focus detection unit,
Reference numeral 22 denotes a shutter device. Further, 23 is a back cover, 24
Is an upper cover, 25 is a front cover, 26 is a bottom cover,
These constitute an exterior member of the camera. The rear wall of the front cover 25 has a flat portion 25a that comes into contact with the flat portion 2f of the mirror box 2.

FIG. 3 is an exploded perspective view of the finder optical system, and FIG. 4 is a partially enlarged view showing details inside the mirror box. As shown in FIGS. 3 and 4, a finder optical system holding portion above the mirror box 2 has a shelf 2a having an opening for guiding a light beam of the finder optical system, and walls 2b, 2c surrounding four sides thereof. 2d and 2e are provided. Of these walls, the back wall 2e is provided with a finder light flux deflected by the pentaprism 13 for the eyepiece lens 1.
Openings for guiding to 6a and 16b are formed. A hook 2i and a hole 2j are formed in the side walls 2c and 2d. Outer holes 20 in the thickness direction are provided at two places on the left and right of the front wall 2b above the lens mount 3 in the wall.
a, 20b and groove 20 provided to be inclined inward
c and 20d communicate with each other to form respective passages.

Next, a procedure for assembling the finder optical system components to the finder optical system holding portion of the mirror box 2 will be described with reference to FIG. First, the field mask 9 is placed on the shelf 2a of the mirror box 2 from above, and then the condenser mask 11, the spacer 12, and the pentaprism 13 are dropped in this order. And cover 1
4 is placed on the pentaprism 13, the spring member 15 is hung on the hook 14 a of the pentacover 14, the hook 2 i and the hole 2 j of the mirror box 2, and the pentaprism 13 is directed downward toward the shelf 2 a of the mirror box 2. Energize.
Further, gaps between the pentaprism 13 and the walls 2b, 2c, 2d, 2e of the mirror box 2 are sealed with a silicone adhesive B as shown in FIG. Here, the condenser lens 11 has curved surfaces on both the entrance side 11a and the exit side 11b. The spacer 12 has an opening through which the light beam of the finder optical system passes, and the incident side 12 a of the spacer 12 is connected to the exit side curved surface 11 of the condenser lens 11.
b, and the emission side 12b is formed as a plane following the incident surface 13a of the pentaprism 13.
Further, notches 1 are provided at positions corresponding to the two grooves 20c and 20d of the mirror box 2 in the spacer 12.
2c and 12d are provided.

FIG. 5 shows a closed space 27 of the finder optical system.
FIG. 4 is an explanatory diagram showing how dust and the like inside are removed. FIG.
The air flow direction changing member 28 in the closed space 27 of the finder optical system will be described with reference to FIG. As shown in FIG. 5A, the nozzle A of the air compressor or the like is
0a and the air flows into the closed space 27,
As shown in FIG. 5 (b), the air supplied to the hole 20a impinges on the flow direction changing member 28 provided at a predetermined angle outside the viewfinder viewing range (the air flow changing member 28 may be provided in a plurality as necessary). can do). As a result, the direction of flow of the air is changed toward the center of the optical axis of the finder optical system, and after the dust or the like existing at the center of the optical axis of the finder optical system is blown off, the air is discharged from the hole 20b.

As shown in FIG. 1, the flat portion 2f of the two holes 20a and 20b on the front face of the mirror box 2 and the rear wall flat portion 25a of the front cover 25 are in contact with each other. In the finder optical system configured as described above, the closed space 27 from the emission-side curved surface 11b of the condenser lens 11 to the entrance surface 13a of the pentaprism 13 is almost closed. Therefore, intrusion of dust from the outside into the closed space 27 is prevented as much as possible. In addition, dust from the outside may adhere to the focusing screen 5 constituting the focal plane. In this case, if the holding frame 6 is rotated downward by pulling the leaf spring 7 shown in FIG. The focusing screen 5 can be removed, and dust and the like can be easily removed by blowing off dust and the like. Further, dust on the incident surface 11a of the condenser lens 11 is also removed from the focusing screen 5 in the same manner.
If dust and the like are blown off with a blower or the like, it can be easily removed.

As described above, dust attached to the portion exposed to the outside can be easily removed by the user. However, dust may enter the enclosed space 27 during assembly, or the pentaprism 1
These foreign substances may enter the field of view of the finder due to the peeling off of the coating on 3.
This case will be described below.

FIGS. 6A and 6B show a single-lens reflex camera to which the present invention is applied, wherein FIG. 6A is a front view, and FIG.
Has been removed. First, from the state of FIG. 6A, the front cover 25 is removed as shown in FIG. 6B to expose the front surface of the mirror box 2. Thereby, the hole 2
0a, 20b, grooves 20c, 20d, and notch 12
The inside and outside of the closed space 27 can be communicated with each other by the passage composed of c and 12d. And, as shown in FIG.
A nozzle A such as an air compressor is inserted into the hole 20a, and air flows into the closed space 27. The flowing air changes the flow direction of the air to the center of the optical axis of the finder optical system by the flow direction changing member 28 having a predetermined angle outside the finder visual field range. As a result, dust and paint pieces adhering to the exit side curved surface 11b of the condenser lens 11 and the entrance surface 13a of the pentaprism 13 are blown off and discharged from the hole 20b. Thereby, the closed space 2
The dust can be easily removed from the finder field of view.

As described above, according to the embodiment of the present invention, simply removing the front cover 25 allows air to flow through the hole 20a (or 20b) of the mirror box 2,
Dust and the like can be discharged from the hole 20b (or the hole 20a). Thereafter, the work is completed only by attaching the front cover 25.

In the above embodiment, the case where dust and the like in the closed space 27 of the finder optical system of the camera are removed has been described. However, the present invention is not limited to the closed space 27 in other parts of the camera and optical devices other than the camera. The present invention can also be applied to the case where dust and the like are removed from the closed space 27 in the device.

In the above embodiment, the mirror box 2 corresponds to a holding member, the condenser lens 11 and the pentaprism 13 correspond to a plurality of optical components, and the holes 20a and 20b and the grooves 20c. , 20d correspond to the passage, and the front cover 25 corresponds to the exterior member.

[0032]

As described above, according to the first aspect of the present invention, there is provided a camera finder including a plurality of optical components forming an optical path, wherein the presence of dust and the like in the optical path is undesirable. An optical system, comprising: a closed space provided between the plurality of optical components; an air inflow hole communicating the closed space with the outside of the machine; and an air outflow hole, and a visual field in a direction in which the air inflow hole extends. By using a camera having an air flow direction changing member provided with a predetermined angle outside the range, a plurality of optical components are used for a finder optical system, and the air flow direction changing member is used outside the view range. So that without obstructing the viewfinder field of view,
The dust generated in the closed space formed between the optical components can be easily removed.

Further, since the air flow direction changing surface is provided with the air flow direction changing member at a predetermined angle with respect to the flow direction of air from the passage, the air flow direction can be easily transferred to a portion where dust or the like easily adheres. If the direction is selected, the air can be circulated evenly in the closed space, and the dust and the like can be efficiently discharged.

According to the invention described in claim 2 of the present application, since the air flow direction changing member is provided near the outlet of the passage on the air supply side, a portion to which dust or the like easily adheres, or an attachment of the dust or the like. Can create an airflow towards undesirable areas.

According to the invention of claim 3 of the present application, since the plurality of passages provided in the holding member are sealed using an exterior member, dust and the like enter the passages and the closed space from the outside. To prevent

[Brief description of the drawings]

FIG. 1 is a side sectional view showing an embodiment of an optical apparatus (camera) according to the present invention.

FIG. 2 is a perspective view showing a configuration of a main part of the optical device of FIG.

FIG. 3 is an exploded perspective view of the optical device shown in FIG. 2;

FIG. 4 is a perspective view showing a part of the mirror box shown in FIGS. 2 and 3 in detail;

5A and 5B are views for explaining a usage mode of the optical apparatus of the present invention, wherein FIG. 5A is a side sectional view of a finder optical system, and FIG.
FIG. 3 is a plan view showing the inside of a closed space of the finder optical system.

FIGS. 6A and 6B show a single-lens reflex camera as an optical apparatus of the present invention, wherein FIG. 6A is a front view with a front cover attached, and FIG. 6B is a front view with the front cover removed.

7A and 7B show a viewfinder optical system of a camera as a conventional optical device, wherein FIG. 7A is a side sectional view, and FIG. 7B is a plan view of a closed space portion of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Camera main body 2 Mirror box 3 Lens mount 5 Focusing screen 7 Engaging member 9 Field mask 11 Condenser lens 12 Spacer 13 Penta prism 20a, 20b Hole 20c, 20d Groove 25 Front cover 26 Bottom cover 27 Closed space 28 Air flow changing member 29 Viewfinder viewing range

Claims (3)

[Claims] A plurality of optical components forming an optical path;
In a finder optical system of a camera in which it is undesirable that dust or the like is interposed in the optical path, a closed space provided between the plurality of optical components, an air inlet hole communicating the closed space with the outside of the machine, and an air outlet. A camera having a hole, and having an air flow direction changing member provided with a predetermined angle outside a visual field range in an extension direction of the air inflow hole. 2. The camera according to claim 1, wherein the air flow direction changing member is provided near an outlet of the passage on an air supply side. 3. The closed space has the plurality of passages provided in a holding member, and the plurality of passages are sealed with an exterior member using an exterior member. The camera according to claim 1.