JP2899039B2 - Single-lens reflex camera - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a single-lens reflex camera incorporating a mirror box.

[Conventional technology]

Conventionally, the mirror box of a single-lens reflex camera has been made of aluminum die cast or zinc die cast. Aluminum die cast is most often used because of its light weight and high strength. However, where the dimensional accuracy is severe, secondary processing is required and there is a disadvantage that the cost is high. On the other hand, zinc die cast has extremely high molding dimensional accuracy, does not require secondary processing, and has a cost advantage but has a disadvantage that it is heavy. To solve this problem, it has been proposed to secure the strength of a press metal frame as described in JP-A-57-79929 and insert-mold it into plastic.

More generally, a pentaprism of a single-lens reflex camera is attached to a camera body 601 as shown in FIG.
02 and attach the penta holder 603 to the mirror box 602.
With screws 604 for mounting. A photometric sensor 606 and a photometric lens 605 are attached to the penta holder 603, and a focus plate 607 and a pentaprism 608 are attached and positioned. Since the penta holder 603 has a complicated shape and severe dimensional accuracy, plastic molded products are frequently used.

[Problems to be solved by the invention]

However, in the above conventional example, although the secondary processing is reduced and there is a cost advantage, two steps of metal pressing and insert molding are required. Pressed metal has limited shape and cannot handle complicated shapes. Since the press metal is used, the weight is still heavy, and since the penta-holder has the variance in the assembling position of the focusing plate and the penta-prism, it is necessary to adjust the photographing focus and the finder observation focus.

[Means for solving the problem]

The invention according to claim 1 is a single-lens reflex camera having a mirror box in which a mounting seat for a photographing lens, a mirror mounting portion for supporting a movable mirror, and a mounting portion for a camera body are formed, wherein the mirror box is integrally formed of plastic. In addition to the molding, a wall portion for holding an optical component for guiding the reflected light of the mirror to a finder observation position is formed at an upper end portion of the side surface where the mirror mounting portion is formed.

According to a second aspect of the present invention, there is provided a single-lens reflex camera having a mirror box in which a mounting seat for a photographing lens, a mirror mounting portion for supporting a movable mirror, and a mounting portion for a camera body are formed, wherein the mirror box is made of plastic. While molding, an optical component for guiding the reflected light of the mirror to a viewfinder observation position is held at a position connecting a mounting portion to the camera body formed behind the mirror box and a mounting seat of the photographing lens. It is characterized in that a wall portion is formed.

〔Example〕

FIGS. 1 to 3 show an embodiment of the present invention. FIGS. 1 and 2 are exploded perspective views of a portion related to the present invention in a single-lens reflex camera, and FIG. 3 is a sectional view thereof.

In the drawing, reference numeral 501 denotes a main body block which forms a mirror box of a single-lens reflex camera and serves as a base for holding various members described later. This main body block is made of polycarbonate reinforced with glass fiber and carbon fiber, and can achieve extremely high dimensional accuracy by processing by injection molding.

Table 1 compares the properties of reinforced polycarbonate, which is the material of the main body block 501, and zinc alloy and aluminum alloy, which have been frequently used as materials of conventional mirror box components. Here, PC-CF20 / GF10 is a reinforced polycarbonate, ZDC is a zinc alloy, and ADC is an aluminum alloy. Generally, ADCs are frequently used, but where precision is required, secondary processing is performed. ZDC has good dimensional accuracy, so secondary processing is unnecessary, but it has a heavy disadvantage.

As shown in the table, the thermal expansion coefficients of the three were PC-CF20 / GF1
In the order of 0 <ADC <ZDC, ZDC is satisfied in absolute value. The longitudinal modulus is in the order of PC-CF20 / GF10 <ADC <ZDC, but there is a large difference of about 6 times between PC-CF20 / GF10 and ADC. The tensile strength is in the order of PC-CF20 / GF10 <ZDC <ADC, but there is about a two-fold difference between PC-CF20 / GF10 and ZDC. In other words, if the mirror box of a single-lens reflex camera made of conventional ZDC or ADC is replaced with reinforced polycarbonate, there will be no problem of focus change due to temperature, and even though the weight will be about 1/5 compared to ZDC, it will be deformed by external force. About six times, the breaking strength will be about 1/2. That is, in the reinforced polycarbonate, the temperature change and the weight are improved, but the deformation and the strength are deteriorated. However, since it is impossible to take a photograph with external force applied to the deformation, it is not a problem if the camera returns to the original state with the external force removed. In addition, it is sufficient to reinforce the breaking point to twice the thickness for the strength. First
The main body block shown in the figure has been improved in shape in order to compensate for the weak point of low tensile strength to realize high dimensional accuracy and light weight. The following description will be given together with members to be assembled.

First, the body block 501 according to the present invention and the camera body 5
The connection with 10 will be described.

In FIG. 15, reference numeral 510 denotes a camera base provided with a film cartridge storage section, a battery storage section, a film take-up section, an eyepiece holding section, and the like, similar to the main body block 501.
It is integrally molded from polycarbonate reinforced with glass fiber or the like.

As shown in FIGS. 1 to 3, the main body block 501 has an AF unit 511 from the bottom, a liquid crystal display unit 503 and a shutter unit 507 from the rear, and a communication contact with the photographing lens from the front. The strobe light control unit is assembled, and the mount 515 is connected to the mount 515 by screws 18 with the mount holding spring 513 and the spacer 514 sandwiched from the front. In this state, the mount 515 is connected to the base 510. FIG. 11 and FIG. 16 are explanatory views of the base connecting position in the main body block 501.
k is a female thread for mounting the mount provided in the main body block 501, 501l and 501m are through holes for passing the coupling screw 516 with the base, and 501o and 501p shown in FIG. The mounting female screws 501n and 501r are positioning holes for the base. On the other hand, as shown in FIG.
c, 510d and through holes 510e, 510f are provided.Furthermore, positioning pins 510a, 510b are provided at positions corresponding to the positioning holes 501n, 501r of the main body block 501. Body block by screw 517
The connection between 501 and substrate 510 is made.

Next, generation of stress when a photographing lens is mounted on a structure in which the main body block 501 and the base body 510 are connected will be described.

FIG. 17 shows a state in which a photographing lens 521 is mounted on a mount 515, in which F is the weight of the photographing lens, 519 is a tripod screw seat attached to the base body, 520 is its fixing screw, and 522 is a tripod cloud. The fixed object of the camera, such as a table, and the two-dot chain line are the exterior members of the camera. As described above, when the camera is supported by a tripod or a photographer, a compressive stress is generated mainly in the E portion and a tensile stress is generated in the G portion in the main body block 501 due to the weight of the photographing lens. The weight of the photographic lens may exceed 1 kg, and especially when the lens is attached and any impact is applied, the main body block 501
The force applied to is extremely large.

As shown above, in the zinc alloy type mirror box, since its tensile strength is large, it does not break even with such a force, but the material is reinforced polycarbonate with the same shape. If replaced, usually G
In the part, the stress exceeds the tensile strength, which breaks. In the present invention, the strength is improved by integrating the mirror box and the holding member of the pentaprism 311 to realize a high-precision camera structure. This will be described below with reference to the drawings.

FIG. 12 is a sectional view of the body block 501 taken along the line A--A shown in FIG.
In the drawing, reference numeral 311 denotes a pentabrhythm, and 310 denotes a focus glass. In the figure, 501s, 501
t is a wall of the main body block provided at a position connecting the mounting screw 518a at the top of the mount and the connecting screw 517 of the base 510 and the main body block 501. Thereby, the portion where the tensile force acts most is reinforced, which is extremely effective in reducing the tensile stress of the portion G shown in FIG. According to experiments, it has been confirmed that by adding the wall portions 501s and 501t, even if it is made of reinforced polycarbonate, there is no such reinforcement, and the strength is increased to about the same level as a mirror box made of zinc alloy. I have.

In addition, the pentaprism 311 can be directly held inside the walls 501s and 501t by utilizing the shock absorbing property of the main body block 501 made of resin. Therefore, unlike the related art, it is not necessary to separately provide a pentaprism holding member, which is advantageous in cost.

Further, since the main body block can be molded with high precision by injection molding, the adjustment of the flange back of the camera is not required, and the number of assembling steps is greatly reduced.

Next, the mirror unit holding mechanism of the main body block 501 and the structure for holding the finder display member will be described with reference to the drawings.

First, in FIGS. 1 and 3, reference numeral 502 denotes a mirror unit. The mirror unit is composed of a movable half mirror that divides the light beam from the photographing lens into a front system and a focus detection system, and a sub mirror that can swing with respect to the movable half mirror and guides the light beam to the auto focus unit at the bottom bottom of the mirror box. I have. FIG. 4 and FIG. 5 are FIG.
FIG. 3 is a view showing a method of supporting the mirror unit shown in FIG. 3 by the main body block 501, and is a view in which a section of a mirror box is viewed from the left and right. In the figure, the part incorporating the mirror mechanism of the main body block 501 is the mirror box 120.
Is simplified.

In the drawing, reference numeral 16 denotes a holding frame for the half mirror 309, which is supported by the shafts 16b and 16d so as to be swingable with respect to the mirror box 120 as described later, and is integrated with the main body block by a spring biasing force applied to the drive pin 16a in the direction of arrow H. Molded stoppers 50
Pressed to 1a. A sub-mirror 315 is fixed to the sub-mirror receiving plate 25, and is swingably supported by a shaft 16c provided integrally with the half mirror holding frame 16.
The spring 29 is supported by the spring hook 16d, and one end of the arm is
Abuts against the half mirror holding frame 16 and the other end receives the sub mirror
It comes into sliding contact with the 25 working portion 25c. This forms a toggle inversion mechanism that urges the sub mirror receiving plate 25 in the opening direction with respect to the half mirror holding frame 16 at the mirror down position and urges the sub mirror receiving plate 25 in the closing direction at the mirror up position (not shown). I have.

Reference numeral 121 denotes an eccentricity-adjustable pin implanted on the side of the mirror box, and a first arm portion 25a of the sub-mirror receiving plate 25.
The half mirror 26 determines the opening angle of the half mirror 26 in the viewfinder observation state, and moves the second mirror 25
b, and has a role of causing the above-described toggle inversion mechanism to perform an inversion operation. Here, reference numeral 121a denotes a flange of the eccentric pin, which prevents the eccentric pin 121 from falling when the angle of the sub-mirror is adjusted by rotating the eccentric pin 121 around a caulking foot (not shown).

U-shaped grooves 120d and 120b as shown in FIG. 6 are formed in the walls on both sides of the mirror box 120, and the shafts 16d and 16b of the half mirror holding frame 16 described above are respectively fitted to be rotatable. It is configured to be. Also, 122, 1
Reference numeral 23 denotes a holding plate for closing the opening of the U-shaped groove, which is made of a thin metal plate, is attached to the mirror box 120 by screws 124 and 125, and forms a bearing together with the U-shaped groove.

As described above, the half mirror holding frame has the U-shaped groove 120d,
Positioning is made at three points, 120b and the stopper 501a, all of which are integrally formed with the main body block. As described above, the material of the main body block 501 is made of reinforced polycarbonate, thereby It is possible to extremely accurately control the positional relationship.

As a result, the angle adjustment of the half mirror, which has been conventionally performed, becomes unnecessary, and the adjustment mechanism therefor is also eliminated. Next, in the folder in the main body block 501,
A method for holding the superimpose display mechanism will be described. FIG. 7 shows the elements shown in FIG. 1 to FIG.
FIG. 3 is a diagram illustrating a main part of a superimposed display.

In the figure, reference numeral 313 denotes a light projecting lens for displaying a superimposed distance measurement visual field. A light beam emitted from three display LEDs (one of which is shown in FIG. 3) is used as a half mirror 309.
And a Fresnel lens portion 313a for forming an image of the mask 508 shown in FIGS. 3 and 8 on the focusing glass 310 via the half mirror 309. ing. The above-mentioned LEDs for display are sealed by transparent packages 314b, c and d made of resin, respectively, and the main body block 501 holds them by fitting them into three grooves at the upper part of the front surface. Further, as shown in FIG. 8, the mask 508 has three LED packages.
It has three openings 508b, 508c, 508d corresponding to 314b, c, d, and is directly fixed by positioning pins 501b of the main body block, like the LED package.

FIG. 11 shows the light emitting lens 3 in the main body block 501.
FIG. 13 is a diagram for explaining a holding method of the main body block 501.
FIG. 2 is a plan view seen from the X direction in FIG. Positioning pins 501c and 501d are implanted in the upper part of the front of the main body block, while the light projecting lens 313 has positioning holes 313e and 313f in its wings 313c and 313d. As shown in FIG. 1, the light projecting lens 313 is assembled from the front of the main body block 501, and the positioning pin of the main body block 501 and the light projecting lens 3 are mounted.
The two are connected by fitting the 13 positioning holes. At this time, the light incident surface 313b of the light projecting lens 313 enters from the opening 501e of the main body block 501 in the direction of the pentaprism 311 and can take in the LED light.

Next, a method of holding the focus graph 310, which is an object to be irradiated with LED light, will be described with reference to FIGS. Twelfth
FIG. 13 is a cross-sectional view of the main body block 501 at a position AA shown in FIG. 2, and FIG. 13 is a detailed view of a portion B in FIG.
As shown in FIG. 1, the focus glass 310 is incorporated at a position below the pentaprism 311 through an opening of the main body block 501 on the photographing lens mounting side, and is held by a pressing spring 505. In FIG. 12, 501f and 501g are main body blocks 50.
The focus glass positioning surface formed in FIG. 1 has four reference surfaces 310i-1 and 310i-
2 comes in contact with each other. Also focus glass 310
Two projections 310j and 310k are arranged on the side surface of the, and the action parts 505a and 505b of the pressing spring 505 abut as shown in FIG. The focusing glass 310 is urged in the direction of FIG. 13B by incorporating the pressing spring 505 into the spring hooks formed on the main body block and the light shielding plate 504, respectively. And reference planes 310i-1, 310i
-2 is adhered. A concave portion 310h is formed on the side surface of the focus glass 310, and the focus glass 310 is biased to the focus glass positioning surface 501h (third illustration) of the main body block 501 by the D-direction component of the urging force of the pressing spring 505. At the same time, the concave portion 310h of the focus glass is fitted to the convex portion (not shown) formed on the positioning surface, and the position of the focus glass in the direction orthogonal to the optical axis is determined.

The operation of the superimposed display with the above configuration will be described below.

The light beams emitted from the LEDs 2, 3, and 4 first pass through the openings 508b, c, and d of the mask 508, and enter the surface 313b of the light projecting lens 313. The light is totally reflected twice inside the light projecting lens 313 and is emitted from the Fresnel lens unit 313a toward the half mirror 309. The light beam reflected by the half mirror 309 forms images 509b, 509c, and 509d of the openings of the mask 508 on the matte surface 310g of the focus graph as shown in FIG. On the matte surface of the focus graph, there are three distance measurement field frames 31 as shown in FIG.
0b, 310c, and 310d are formed as an aggregate of a large number of micro prisms. As shown in the cross section in FIG. 10, only the light beam (for example, 322) incident on the micro prisms is deflected upward, The light is guided to the eyepiece through the prism 311. The LED light (for example, 323) that has not entered the micro prism is diffused on the matte surface 310g and then absorbed by the black painted surface 311a of the pentaprism 311 shown in FIG. do not do. Therefore, the LED
When the lights 2, 3, and 4 are selectively turned on, the corresponding distance measuring frame on the focus glass changes its color to the emission color of the LED.

Here, in order to selectively change the color of the focusing frame,
The illumination range of the LED light shown in FIG. 14, that is, the mask image 509
It is necessary that b, 509c, and 509d do not overlap the adjacent ranging frames, and in order to uniformly change the color of one ranging frame, the mask images 509b, 509c, and 509d are shifted from the corresponding ranging frame. It is necessary that they do not come off. Thus, in order to enhance the quality of the superimposed display, the mask image 509b,
It is important to guarantee the positions of c and d. Mask image 50
The positions of 9b, c, and d are as follows: the light emitting unit (LED), the illumination range regulating member (mask 508), the imaging system (light projection lens 313), the light deflecting means (mirror unit 502), and the illuminated object (focus graph 31).
Since it changes sensitively depending on the position of 0), extremely strict positional accuracy is required for each component. In this embodiment, as described above, the main body block 501 is used.
However, by directly holding all of these elements, the above-described inconvenience does not occur, and a high-quality superimposed display is realized.

As a secondary effect of the high positional accuracy of the movable half mirror 309 and the focus glass 310 and the fact that the above-mentioned flange back can be accurately assured, there is an improvement in the finder focus accuracy.

〔The invention's effect〕

The invention according to claim 1 is a single-lens reflex camera having a mirror box in which a mounting seat for a photographing lens, a mirror mounting portion for supporting a movable mirror, and a mounting portion for a camera body are formed, wherein the mirror box is integrally formed of plastic. A conventional metal mirror box is formed by forming a wall portion for holding an optical component for guiding reflected light of the mirror to a finder observation position at an upper end portion of a side surface where the mirror mounting portion is formed. In addition to obtaining the same strength as that of the first embodiment, an optical component for guiding the reflected light of the mirror to the finder observation position can be directly held in the mirror box, so that a lightweight and highly accurate single-lens reflex camera can be provided. it can.

According to a second aspect of the present invention, there is provided a single-lens reflex camera having a mirror box in which a mounting seat for a photographing lens, a mirror mounting portion for supporting a movable mirror, and a mounting portion for a camera body are formed, wherein the mirror box is made of plastic. While molding, an optical component for guiding the reflected light of the mirror to a viewfinder observation position is held at a position connecting a mounting portion to the camera body formed behind the mirror box and a mounting seat of the photographing lens. By forming the wall part, the same strength as that of the conventional metal mirror box can be obtained, and the optical components for guiding the reflected light of the mirror to the viewfinder observation position can be directly held in the mirror box. Therefore, a lightweight and highly accurate single-lens reflex camera can be provided.

[Brief description of the drawings]

1 and 2 are exploded perspective views of a camera as an embodiment, FIG. 3 is a sectional view in the optical axis direction, FIGS. 4 to 6 are views showing a mirror mounting portion, and FIGS. The figure shows the superimpose in the viewfinder, FIG. 11 shows the mount mounting surface, FIG. 12 shows the sectional view in the optical axis direction, FIG. 13 shows the focus plate mounting part, and FIG. FIG. 15 is a perspective view of the camera body, FIG. 16 is a plan view seen from the rear surface, FIG. 17 is a cross-sectional view in the optical axis direction with a lens attached, FIG. It is a perspective view showing a conventional example. 501… Mirror box main body block 502… Mirror unit 507… Shutter unit 511… Mount 310… Focus glass 311… Pentaprism 313… Flood lens 314… LED

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G03B 17/02 G03B 13/24-13/26

Claims (4)

(57) [Claims] 1. A single-lens reflex camera having a mounting box for a photographing lens, a mirror mounting portion for supporting a movable mirror, and a mirror box in which a mounting portion to a camera body is formed. A single-lens reflex camera, wherein a wall for holding an optical component for guiding reflected light of the mirror to a finder observation position is formed at an upper end portion of a side surface where the mirror mounting portion is formed. 2. A single-lens reflex camera having a mount for a taking lens, a mirror mount for supporting a movable mirror, and a mirror box in which a mount for a camera body is formed. A wall that holds an optical component for guiding the reflected light of the mirror to a finder observation position at a position connecting a mounting portion to the camera main body formed behind the mirror box and a mounting seat of the photographing lens. A single-lens reflex camera characterized by being formed. 3. The single-lens reflex camera according to claim 1, wherein the mirror box is integrally formed of polycarbonate. 4. The single-lens reflex camera according to claim 1, wherein the mirror box is formed by injection molding.