JP4281328B2 - Camera and viewfinder mirror unit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a camera employing a roof mirror in a finder optical system, and a finder mirror unit.
[0002]
[Prior art]
As a mirror unit used for a finder of a single-lens reflex camera, there is a unit using a hollow penta roof mirror. The penta roof mirror is also called a roof type reflecting mirror or the like, and has a roof type roof mirror portion having a pair of reflecting surfaces orthogonal to each other, and a third reflecting surface for guiding reflected light from the roof mirror portion to the eyepiece. Since each mirror part is made into a thin plate shape in order to improve moldability, the weight can be significantly reduced as compared with a solid glass prism (penta prism) having the same function.
[0003]
As a structure for attaching the penta roof mirror to the camera, there is a structure in which unevenness is provided on both the penta roof mirror side and the support side, and the unevenness is engaged and fixed (see, for example, Patent Document 1). There is also one that uses a spring member to press and fix the penta roof mirror to the camera body side (see, for example, Patent Document 2).
[0004]
[Patent Document 1]
Japanese Patent No. 3170540 (paragraph 0022, FIGS. 3 and 4)
[Patent Document 2]
JP-A-11-218803 (paragraph 0016, FIG. 2)
[0005]
[Problems to be solved by the invention]
However, the structure of any of the above documents has a problem that a gap is always generated between the lower surface of the penta roof mirror and the main body, and dust enters the finder from the gap. As a method of eliminating the gap, it is conceivable that the penta roof mirror is attached using an adhesive, in other words, an adhesive is interposed between the penta roof mirror and the main body side attaching portion. However, as described above, since the penta roof mirror is thin, the penta roof mirror may be deformed by a pressing force at the time of bonding or shrinkage deformation at the time of curing of the adhesive itself, and there is a possibility that the viewfinder image may be distorted. Although it is conceivable to use a silicone rubber-based adhesive that has little shrinkage deformation at the time of curing, the assembly time of the mirror unit deteriorates due to the long curing time.
[0006]
An object of the present invention is to provide a camera and a finder mirror unit that have good assembly efficiency of the mirror unit, have no distortion of the finder image, and have an excellent dustproof effect.
[0007]
[Means for Solving the Problems]
The camera according to any one of claims 1 to 5 has first and second reflecting surfaces orthogonal to each other, a roof mirror portion on which a transmitted light beam of a photographing lens is incident, and a first guide for guiding reflected light from the roof mirror portion to the eyepiece portion. A finder mirror unit in which a supported portion for supporting the three reflecting surfaces and the roof mirror portion and the third reflecting surface on the supporting portion of the camera body is integrated, and a finder mirror for preventing dust from entering the finder comprising an elastic dustproof member interposed between the lower surface and the camera body of the unit, and a spring member allowed to support presses the supported portion of the viewfinder mirror unit on the support portion of the camera body, I by the spring member When the supported part is supported by the support part, the bottom face of the finder mirror unit is kept between the camera body and the bottom face of the viewfinder mirror unit is kept between the camera body and the elasticity. The dustproof member is configured to maintain a state of being elastically deformed by a pressing force by a spring member.
According to the second aspect of the present invention, a pair of supported portions are provided so as to protrude from each of two opposing side surfaces of the finder mirror unit, and the center portion is fixed to the camera body, thereby generating elastic forces at both ends. The plate springs are provided as the spring members, and the two supported parts are pressed against the support parts at both ends of the pair of plate springs.
According to the invention of claim 5 , the elastic dustproof member is constituted by a sponge-like member.
According to a sixth aspect of the present invention, there is provided a finder mirror unit having first and second reflecting surfaces orthogonal to each other, a roof mirror portion on which a transmitted light beam of a photographing lens is incident, and reflected light from the roof mirror portion to an eyepiece portion. Between the third reflecting surface, the supported mirror for supporting the roof mirror portion and the third reflecting surface on the supporting portion of the camera body, and between the bottom surface of the finder mirror unit and the camera body so as to prevent dust from entering the finder. And a spring member that presses and supports the supported portion against the support portion of the camera body, and when the supported portion is supported by the support portion by the spring member, The elastic dustproof member sandwiched between the lower surface of the finder mirror unit and the camera body is elastically deformed by the pressing force of the spring member with the lower surface kept at a distance from the camera body. Characterized by being configured to maintain the state.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to FIGS.
FIG. 1 shows the vicinity of a viewfinder of a single-lens reflex camera in the present embodiment. A subject luminous flux that has passed through a photographing lens (not shown) is guided into the camera body 2 from the opening 1a of the lens mount 1, a part of which is reflected upward by the main mirror 3, and passes through the focusing screen 4 to pass through the finder mirror unit. Is incident on the penta roof mirror 10.
[0009]
1 to 4, a penta roof mirror 10 is connected to a roof type roof mirror section 11 having a pair of reflecting surfaces (first and second reflecting surfaces) 11 a orthogonal to each other and both left and right ends of the roof mirror section 11. A pair of side walls 12, a reflection member 13 disposed in front of the lower part of the roof mirror 11, and an emission wall 14 disposed behind the roof mirror 11 are integrated. The transmitted light beam of the focusing screen 4 is first reflected twice by the roof mirror 11 and guided forward, and then reflected backward by the third reflecting surface 13 a formed on the reflecting member 13 and passes through the opening of the exit wall 14. Then, it is guided to the eyepiece 5 as an erect image. The eyepiece 5 is fixed to a standing wall 2 c provided at the rear part of the camera body 2.
[0010]
The penta roof mirror 10 and its mounting structure will be described in further detail.
The roof mirror portion 11 is a plastic molded product, and a reflective film 11a is formed by vapor-depositing a metal film on two inner surfaces. The reflective member 13 is a molded product of glass or plastic, and the third reflective surface 13a is formed in advance on the inner surface by vapor deposition of a metal film. The reflecting member 13 is fixed to the roof mirror 11 and the pair of side walls 12.
[0011]
The lower end surfaces of the pair of side walls 12, the reflecting member 13, and the exit wall 14 are flush with each other, and a rectangular lower surface P is formed by these four end surfaces. Front projections 12a project from the outer surfaces of the side walls 12 at positions slightly higher than the lower surface P, and rear projections 14a project from both sides of the injection wall 14 at the same height as the front projections 12a. It is installed. The left and right pair of four protrusions 12a and 14a constitute a supported portion that is pressed toward the camera body by a leaf spring 32 described later.
[0012]
On the other hand, a positioning portion 2a corresponding to the shape of the penta roof mirror 10 is formed on the camera body 2, and the penta roof mirror 10 is positioned in the left and right and front and rear directions by the positioning portion 2a. A pair of left and right bulged portions 2b are formed at a position slightly higher than the bottom surface of the positioning portion 2a, and a spring seat 2d is formed between the front and rear bulged portions 2b. The four bulging portions 2b constitute support portions that support the entire penta roof mirror 10 by supporting the protrusions 12a and 14a, respectively. These bulging portions 2b and protrusions 12a and 14a are formed with high precision so that the penta roof mirror 10 does not tilt when supported.
[0013]
Reference numeral 20 in FIG. 1 denotes an in-viewfinder display device, which includes a display element 21 such as an LCD or LED, and a prism 22 for guiding display contents of the display element 21 to the eyepiece 5. The upper surface of the prism 22 constitutes a part of the bottom surface of the positioning portion 2a.
[0014]
An elastic dustproof member 31 is interposed between the lower surface P of the penta roof mirror 10 and the bottom surface of the positioning portion 2a of the camera body 2. The elastic dustproof member 31 has the same shape as the lower surface P, that is, a quadrangular shape having an opening, and is fixed to the lower surface P or the finder field frame 41 in advance. As the material of the elastic dustproof member 31, a relatively soft material, for example, a sponge-like material is desirable.
[0015]
The penta roof mirror 10 is fixed to the camera body 2 by a pair of leaf springs 32. That is, when the penta roof mirror 10 is positioned on the positioning portion 2 a via the elastic dust-proof member 31, the four protrusions 12 a and 14 a are positioned above the bulging portion 2 b of the camera body 2. In this state, the center portion of the pair of leaf springs 32 is screwed to the spring seat 2d with screws while being elastically deformed. As a result, a downward elastic force is generated at both ends (free ends) of the leaf spring 32, and the protrusions 12 a and 14 a are pressed and supported by the bulging portion 2 b by both ends of the leaf spring 32. In the present embodiment, since the four corners of the penta roof mirror 10 having a quadrangular cross section are pressed by the springs, stable support is possible. Moreover, since the four leaf springs 32 cover the four points of pressing, the number of parts and the number of assembling steps can be reduced and the space efficiency can be improved.
[0016]
Here, as shown in the enlarged view of FIG. 5, the rear protrusion 14 a is provided with a slope, and the slope is pressed against one end of the leaf spring 32. At the same time, it is also pressed rearward, that is, the standing wall 2c of the camera body 2. As a result, it is possible to prevent the positional shift in the front-rear direction and the rotational direction of the penta roof mirror 10 that has a great influence on the optical performance. As can be seen from FIG. 4, the lateral displacement of the penta roof mirror 10 is suppressed by the side walls of the positioning portion 2a.
[0017]
When the protrusions 12a and 14a are pressed by the leaf spring 32, the elastic dust-proof member 31 disposed on the field frame 41 is crushed between the lower surface P and the bottom surface of the positioning portion 2a (partly the upper surface of the prism 22). Thus, the gap between the lower surface P and the bottom surface of the positioning portion is sealed, and dust can be prevented from entering the finder. In particular, in this embodiment, the clearance between the lower surface P and the positioning portion bottom surface is uniform over the entire surface, and as described above, stable support is provided by pressing at four locations. It becomes uniform throughout and provides a reliable dustproof effect.
[0018]
Further, according to the above support structure, the penta roof mirror 10 is pressed and supported at a position above the lower surface P, and the lower surface P itself does not press the bottom surface of the positioning portion 2a. Is only the elastic force of the elastic dust-proof member 31. Since the elastic dust-proof member 31 is a very soft material (for example, sponge-like), its elastic force is extremely small and does not distort the roof mirror 11 (does not affect the finder performance).
[0019]
Further, according to the above support structure, the positions of the pressed parts (protrusions 12a and 14a) and the parts (2b) that receive the reaction force are the same, so that an undesired moment is applied to the penta roof mirror 10. In addition, the distortion of the roof mirror 11 due to the moment can be prevented.
Incidentally, when it is configured to receive a pressing force from the lower surface P on the bottom surface of the positioning portion 2a, the positions of the pressed portions (projections 12a and 14a) and the locations receiving the reaction force (lower surface P) are different. An undesirable moment is applied to the roof mirror 10, and the roof mirror 11 may be distorted.
[0020]
Further, in the present embodiment, since no adhesive is used for mounting the penta roof mirror 10, there is no distortion of the penta roof mirror 10 due to pressing force during bonding or shrinkage deformation during curing of the adhesive. Furthermore, since it is not necessary to consider the curing time of the adhesive, the assembly work efficiency can be improved.
[0021]
As shown in FIG. 6, a protrusion Pa having a sharp tip may be formed on the lower surface P of the penta roof mirror. By causing the ridge Pa to bite into the elastic dustproof member 32, the reaction force received from the elastic dustproof member 32 can be reduced as compared with the case where the lower surface P is flat. Therefore, even if the crushing amount of the elastic dustproof member 32 is increased , the distortion of the roof mirror portion 11 can be suppressed and the dustproof effect can be improved. The protrusion Pa is preferably formed on the entire lower surface P, that is, on each lower end surface of the side wall 12, the reflecting member 13, and the exit wall 14.
[0022]
The spring member for holding the penta roof mirror is not limited to the plate spring as described above, and the position pressed by the spring member is not particularly limited. Although a sponge-like elastic dustproof member is provided, other materials may be used as long as they are soft.
[0023]
【The invention's effect】
According to the present invention, the elastic dustproof member provided between the lower surface of the finder mirror unit and the camera body is pressed by the support portion of the camera body by the spring member and supported by the spring member. Since it is configured to be elastically deformed, there is no gap between the lower surface of the finder mirror unit and the main body, and dust can be reliably prevented from entering the finder. Further, since it is not necessary to use an adhesive, there is no distortion in the roof mirror portion, and the assembly work efficiency can be improved.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a viewfinder structure of a single-lens reflex camera according to an embodiment.
FIG. 2 is a view as seen from line II-II in FIG.
FIG. 3 is a view taken along line III-III in FIG.
4 is a cross-sectional view taken along line IV-IV in FIG.
FIG. 5 is an enlarged view showing a pressing portion by a spring member.
FIG. 6 is a view showing an example in which a protrusion is provided on the lower surface of the penta roof mirror.
[Explanation of symbols]
2 camera body 2a positioning part 2b bulging part 2c standing wall 5 eyepiece 10 penta roof mirror (finder mirror unit)
11 roof mirror part 11a reflecting surface 12 side wall 12a protrusion 13 reflecting member 13a third reflecting surface 14 compartment wall 14a protrusion 20 finder display device 31 elastic dustproof member 32 leaf spring P lower surface of penta roof mirror

Claims (6)

A roof mirror unit having first and second reflecting surfaces orthogonal to each other and receiving a transmitted light beam of the photographing lens, a third reflecting surface for guiding reflected light from the roof mirror unit to the eyepiece unit, the roof mirror unit and the first mirror unit A finder mirror unit in which a supported portion for supporting the three reflecting surfaces on the supporting portion of the camera body is integrated;
An elastic dustproof member interposed between the lower surface of the finder mirror unit and the camera body to prevent dust from entering the finder;
A spring member that presses and supports the supported portion of the finder mirror unit against the support portion of the camera body;
When the supported portion I by the said spring member is supported by the support portion, in a state where the lower surface of the viewfinder mirror unit keeping the camera body and spacing, sandwiched between the lower surface and the camera body of the viewfinder mirror unit The camera according to claim 1 , wherein the elastic dustproof member is kept elastically deformed by the pressing force of the spring member .   The supported portion is provided to protrude by two on each of two opposing side surfaces of the finder mirror unit, and the spring member generates elastic force at both ends by fixing the central portion to the camera body. 2. The camera according to claim 1, wherein the camera is configured such that the two supported portions are pressed against the support portions at both ends of each of the pair of plate springs. One of the two supported portions has a slope inclined with respect to the lower surface of the finder mirror unit, and each end of the pair of leaf springs presses the slope. The camera according to claim 2 . The camera according to any one of claims 1 to 3, wherein a ridge is formed on a mirror side end surface of the lower surface of the finder mirror unit. The camera according to claim 1, wherein the elastic dustproof member is a sponge-like member. A roof mirror unit having first and second reflecting surfaces orthogonal to each other and into which a transmitted light beam of a photographing lens is incident;
  A third reflecting surface for guiding reflected light from the roof mirror to the eyepiece;
  A supported portion for supporting the roof mirror portion and the third reflecting surface on a support portion of a camera body;
  An elastic dustproof member interposed between the bottom of the finder mirror unit and the camera body to prevent dust from entering the finder;
  A spring member that presses and supports the supported portion against the support portion of the camera body,
  When the supported part is supported by the support part by the spring member, the lower surface of the finder mirror unit is held between the lower surface of the finder mirror unit and the camera body while the lower surface of the finder mirror unit is spaced from the camera body. A finder mirror unit characterized in that the elastic dustproof member is configured to maintain a state of being elastically deformed by a pressing force by the spring member.

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