JPH03237444A - Single-lens reflex camera - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a single-lens reflex camera incorporating a mirror box.

[Conventional technology]

Conventionally, mirror hooks for eye reflex cameras have been made of die-cast aluminum or die-cast zinc. Aluminum die-casting was the most commonly used material due to its light weight and high strength, but it had the drawback of requiring secondary processing in areas where dimensional accuracy was critical, resulting in high costs. On the other hand, zinc die casting has very good molding dimensional accuracy and does not require secondary processing, which has cost advantages, but it has the disadvantage of being heavy. In order to solve this problem, it has been proposed to ensure strength as a pressed metal frame and to insert mold it into plastic, as described in JP-A-57-79929.

Furthermore, in general, the pentaprism of a single-lens reflex camera is installed by attaching a mirror box 602 to the camera body 601 and tightening a penta holder 603 to the mirror box 602 with screws 604, as shown in FIG. . In the penta holder 603: photometric sensor 6
06, the photometric lens 605 is attached and the focusing plate 60
7 and a pentaprism 608 are attached and positioned. Since the penta holder 603 has a complicated shape and requires strict dimensional accuracy, a plastic molded product is often used.

[Problem to be solved by the invention] However, although the conventional example described above has a cost advantage by reducing secondary processing, it requires two processes: metal pressing and insert molding. Because it is pressed metal, it has shape limitations and cannot accommodate complex shapes. Since it uses a brush and a metal lens, it is still heavy, and since it has a penta holder, there will be variations in the installation position of the focusing board and penta prism, so it is necessary to adjust the shooting focus and finder observation focus. Ta.

[Means for Solving the Problems] According to the present invention, the entire mirror box including the penta holder that holds the penta prism is integrally molded, thereby achieving high precision and light weight, and overcoming the lack of strength of plastic. be.

In particular, it is possible to provide a single-lens reflex camera that satisfies both the needs of reinforcing the lack of strength caused by plastic mirror boxes and accurate positioning of the finder optical system.

[Example] Figures 1 to 3 show examples of the present invention, Figures 1 and 2 are exploded perspective views of the parts related to the present invention in a single-lens reflex camera, and Figure 3 is a cross-sectional view thereof. It is.

In the figure, 501 is a main body block that forms a mirror box of the single-lens reflex camera and serves as a base for holding various members to be described later. This main body block is made of polycarbonate reinforced with glass fiber and carbon fiber, and is processed by injection molding to achieve extremely high dimensional accuracy.

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 for the components of conventional mirror boxes. Here PC-CF20/GF 1
0 is reinforced polycarbonate, Z D Cif zinc alloy and ADC is aluminum alloy. Generally AD
Secondary processing is performed where C is used extensively or where precision is required.

Z D C: It has good dimensional accuracy and does not require secondary processing, but it has a heavy drawback.

As shown in the table, the thermal expansion coefficients of the three are PC-CF2
Although the order is 0/GF 10<ADC<ZDC (7), ZDC is also satisfactory in absolute value. Longitudinal elastic modulus! 1Pc
-CF20/GF 10<ADC<ZDC (7) Although the order is, there is a large difference of about 6 times between PC-CF20/GF10 and ADC. Tensile strength P C-CF 20/G
The order is F10<ZDC<ADC, but PC-CF2
There is a difference of about 2 times between 0/GF 10 and ZDC. In other words, if you replace the mirror hook of a single-lens reflex camera made with conventional ZDC or ADC with reinforced polycarbonate, there will be no problem with the focus change due to temperature, and although it weighs about 115 mm compared to ZDC, the outer edge will be stiffer. The deformation will be approximately 6 times greater, and the fracture strength will be approximately %. In other words, reinforced polycarbonate improves temperature change and weight, but deteriorates deformation and strength. However, common sense suggests that it is impossible to photograph the deformation while applying an external force, so there is no problem as long as the deformation returns to its original state after the external force is removed. In addition, for strength, it is sufficient to reinforce the fractured area to double the thickness.The main block shown in Figure 1 has been improved in shape to compensate for its low tensile strength, resulting in high dimensional accuracy. It has achieved a reduction in weight, and will be explained below along with the parts that are assembled into it.

First, the connection between the main body block 501 and the camera base 510 according to the present invention will be described.

In FIG. 15, 510 is a film cartridge storage section;
This is the base of the camera, which includes a battery storage section, a film winding section, an eyepiece holding section, etc., and is integrally molded from polycarbonate reinforced with glass fiber or the like, like the main body block 501.

As shown in FIGS. 1 to 3, the main body block 501 includes an AP unit 511 from below, a liquid crystal display unit 503 and a shutter unit 507 from the rear, and a strobe that also has communication contacts with a photographic lens from the front. After the light control unit is assembled, the mount 515 is connected from the front with the mount presser spring 513 and the spacer 514 sandwiched together by the screws 18, and in this state, the base 51
A combination with 0 is performed. 11 and 16 are explanatory diagrams of the base coupling position in the main body block 501, and 501h to 501k shown in FIG. 11 which is a front view are the main body block 50.
Female thread for mounting the mount provided in 1, 50112.
501m is a through hole for passing the coupling screw 516 with the base body, and 501q and 50 shown in FIG. 16, which is a rear view.
1p is a female screw for mounting the base, and 501n and 501r are holes for positioning with the base. On the other hand, the base body 510 has female screws 510c and 510d and a through hole 510e as shown in FIG.
Further, positioning pins 510a and 510b are provided at positions corresponding to positioning holes 501n and 501r of the main body block 501, and when these are fitted, the main body block 501 and the base are connected by screws 516 and 517. 510 is made.

Next, the generation of stress when a photographing lens is attached to a structure in which the main body block 501 and the base 510 are combined will be explained.

Fig. 1.7 shows the state in which the photographing lens 521 is attached to the mount 515, and in the figure, F is the weight of the photographing lens, 51
Reference numeral 9 indicates a tripod screw seat attached to the base body, 520 a fixing screw thereof, 522 a fixing object of the camera such as a tripod head, and the chain double-dashed line indicates an exterior member of the camera. When the camera is supported on a tripod or by the photographer, the main body block 501 is mainly
A compressive stress occurs in the G part, and a tensile stress occurs in the G part. Some photographic lenses weigh more than 1 kg, and when some kind of impact is applied, especially when the lens is attached, the force applied to the main body block 501 becomes extremely large.

As shown above, the zinc alloy type mirror box has a high tensile strength, so it will not break even under such force. When replaced, the stress in the G section usually exceeds the tensile strength, resulting in breakage.

In the present invention, by integrating the mirror hook and the holding member of the pentaprism 311, strength is improved and a highly accurate camera structure is realized.

This will be explained below using figures.

FIG. 12 shows the A of the main body block 501 shown in FIG.
This is a cross section at the position -A, where 311 is a pentaprism and 310 is a focusing glass. In the figure, 5
01s and 501t are the mounting screws 518a on the top of the mount.
This is a wall portion of the main body block that is provided at a position connecting the connecting screw 517 of the base 510 and the main body block 501.

This reinforces the part on which the tensile force is most applied, and is extremely effective in reducing the tensile stress in the G section shown in FIG. 17. According to experiments, this wall portion 501s, 50
It has been confirmed that by adding 1 t, the strength can be increased to the same extent as mirror hocks made of zinc alloy, which do not have such reinforcement, even if they are made of reinforced polycarbonate.

Furthermore, by utilizing the shock absorbing properties of the main body block 501 made of resin, it is possible to directly hold the pentaprism 311 inside the walls 501S and 501t. There is no need to separately provide a pentaprism holding member, which is advantageous in terms of cost.

Furthermore, since the main body block can be molded with high precision by injection molding, there is no need to adjust the flange focal length of the camera, resulting in a significant reduction in assembly man-hours.

Next, the mirror unit holding mechanism of the main body block 501 and the holding structure of the finder display member will be explained using the drawings.

First, in FIGS. 1 and 3, 502 is a mirror unit. The mirror unit consists of a movable half mirror that divides the light flux from the photographing lens into the finder system and the focus detection system, and a sub-mirror that can swing relative to the movable half mirror and guides the light flux to the autofocus unit at the bottom of the mirror box. . Figure 4 and Figure 5 are Figure 1,
4 is a diagram showing a method of supporting the mirror unit shown in FIG. 3 by the main body block 501, and is a cross-sectional view of the mirror box viewed from the left and right sides, respectively. FIG.

In the figure, a portion of the main body block 501 into which the mirror mechanism is incorporated is simplified and shown as a mirror box 120.

Reference numeral 16 in the figure denotes a holding frame for the half mirror 309, which is swingably supported by shafts 16b and 16d relative to the mirror box 120, as will be described later.
It is pressed against a stopper 501a integrally molded on the main body block by spring biasing force in the direction. 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 has a spring hook portion 16d.
, and one end of the arm is attached to the half mirror holding frame 16.
The other end makes sliding contact with the action portion 25c of the sub-mirror receiving plate 25. As a result, the sub-mirror receiving plate 25 is biased in the opening direction with respect to the half-mirror holding frame 16 at the mirror-down position, and the sub-mirror receiving plate 25 is biased at the mirror-up position (not shown).
It forms a toggle reversal mechanism that urges the toggle in the closing direction.

121 is a bin whose eccentricity can be adjusted, which is installed on the side surface of the mirror box, and which is attached to the first arm portion 2 of the sub-mirror receiving plate 25.
5a determines the opening angle of the half mirror 26 in the viewfinder observation state, and when moving in the shooting retraction direction, it comes into contact with the second arm portion 25b of the sub-mirror receiving plate 25, and the above-mentioned toggle reversing mechanism It has the role of causing a reversal operation. Here, 121
Reference character a denotes a flange of the eccentric bottle, which prevents the eccentric bottle 121 from falling when the eccentric bottle 121 is rotated around a caulking foot (not shown) and the angle of the sub-mirror is adjusted.

U-shaped grooves 120d and 120b as shown in FIG. 6 are formed on both sides of the mirror box 120.
The shafts 16d and 16b of the half-mirror holding frame 16 mentioned above are respectively depressed and rotatably fitted into each other. Reference numerals 122 and 123 denote holding plates for closing the openings of the U-shaped grooves, which are made of thin metal plates and are attached to the mirror box 120 with screws 124 and 125, forming a bearing together with the U-shaped grooves.

As described above, the half mirror holding frame has the U-shaped groove 120d.
, 120b and the stopper 501a, and since all of these are integrally molded into the main body block, as mentioned above, by making the material of the main body block 501 reinforced polycarbonate, these It is possible to determine the positional relationship extremely accurately.

As a result, the angle adjustment of the half mirror, which was previously done, is no longer necessary, and the adjustment mechanism for that purpose is also abolished.
Add an explanation about how to hold the superimpose display mechanism. Figure 7 shows the elements shown in Figures 1 to 3.
FIG. 3 is a diagram showing main parts configuring a superimposed display.

In the figure, 313 is a light projecting lens for displaying a superimposed distance measurement field of view. The luminous flux emitted from three display LEDs (one of which is shown in Figure 3) is reflected by a half mirror.
309, and a Fresnel lens section 313a for forming the image of the mask 508 shown in FIGS. 3 and 8 on the focusing glass 310 via the half mirror 309. are doing. Note that the above display LEDs are each made of resin transparent packages 314b and 314c.
, d, and is held by the main body block 501 by fitting these into three grooves on the upper front surface. Furthermore, as shown in FIG. 8, the mask 508 has three openings 508b, 508c, and 508d corresponding to the three LED packages 314b, c, and d, and the mask 508 has three openings 508b, 508c, and 508d corresponding to the three LED packages 314b, c, and d. It is directly fixed by the bin 501b.

FIG. 11 is a diagram for explaining a method of holding the light projecting lens 313 in the main body block 501, and is a plan view of the main body block 501 viewed from the X direction in FIG. A positioning bin 501c is located at the front upper part of the main block.
, 501d are implanted, and on the other hand, the projection lens 313 has positioning holes 313e, 31 in its wing portion 313C1313d.
3f is provided. As shown in FIG. 1, the light projecting lens 313 is assembled from the front of the main body block 501, and the positioning bin of the main body block 501 and the positioning hole of the light projecting lens 313 fit together, thereby coupling the two. At this time, from the opening 501e of the main body block 501,
A light incident surface 313b of the light projecting lens 313 enters in the direction of the pentagonal prism 311 and can take in the LED light.

Next, a method for holding the focusing glass 310, which is an object to be irradiated with LED light, will be explained using FIGS. 12 and 13. FIG. 12 shows the A of the main body block 501 shown in FIG.
-A cross section at position A, FIG. 13; and a detailed view of section B in FIG. 3. As shown in FIG. 1, the focusing glass 310 is installed at a position below the pentaprism 311 through the opening of the main body block 501 on the side where the photographic lens is attached.
It is held by a presser spring 505. In FIG. 12, 501f and 501g are focusing glass positioning surfaces formed on the main body block 501, and the four reference surfaces 310i-1 and 310i-2 of the focusing glass 310 come into contact with these surfaces. Further, two protrusions 310j and 310k are provided on the side surface of the focusing glass 310, and as shown in FIG.
505b comes into contact. By incorporating the presser spring 505 into the spring hooks formed on the main body block and the light shielding plate 504, the focusing glass 310 is biased in the direction B in FIG.
f, 501g and reference surfaces 310i-1, 310i-2 are brought into close contact. Further, a recess 310h is formed on the side surface of the focusing glass 310, and the focusing glass 310 is biased toward the focusing glass positioning surface 501h (shown in the third figure) of the main body block 501 by the D-direction component of the urging force by the presser spring 505. At the same time, the concave portion 31 of the focusing glass is aligned with the convex portion (not shown) formed on this positioning surface.
0h is fitted, and the position of the focusing glass in the direction perpendicular to the optical axis is determined.

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

The light flux emitted from the LED 2.3.4 first passes through the mask 50.
The light passes through the apertures 508b, c, and d of No. 8 and enters the surface 313b of the light projection lens 313. Inside the projection lens 313, 2
The light is totally reflected twice and is emitted from the Fresnel lens portion 313a toward the half mirror 309. Luminous flux reflected by the half mirror 309: As shown in FIG. 14, an image 509b of the opening of the mask 508 is formed on the matte surface 310g of the focusing glass
, 509c, and 509d. On the matte surface of the focusing glass, there are three distance measuring field frames 310 as shown in FIG.
b, 310c, and 310d are formed as an assembly of a large number of microprisms, and as shown in the cross section in FIG. It is guided through a prism 311 to the eyepiece. Further, the LED light (for example, 323) that did not enter the microprism is diffused by the matte surface 310g, and then absorbed by the black painted surface 311a of the pentaprism 311 shown in FIG. 7, and reaches the eyepiece 312. do not. Therefore, when LED 2.3.4 is selectively turned on, the corresponding distance measurement frame on the focusing glass changes color to the color of the LED light.

Here, in order to selectively change the color of the ranging frame, the first
The illumination range of the LED light shown in Figure 4, that is, the mask image 5
It is necessary that the mask images 509b, 509c, and 509d do not overlap adjacent distance measurement frames, and in order to uniformly change the color of one distance measurement frame, the mask images 509b, 509c, and
It is necessary that 09d does not deviate from the corresponding distance measurement frame.

In this way, in order to improve the quality of superimposed display, it is important to ensure the positions of mask images 509b, c, and d. The positions of mask images 509b, c, and d are as follows:
Light emitting part (LED), illumination range regulating member (mask 508
) Since the imaging system (projection lens 313), light deflection means (mirror unit 502), and illuminated object (focusing glass 310) change sensitively depending on their positions, extremely strict positional accuracy is required for each component. required.

In this embodiment, as described above, the main body block 5
01 is configured to directly hold all of these elements, thereby eliminating the above-mentioned problems and realizing high-quality superimposed display.

Further, as a secondary effect of the high positional accuracy of the movable half mirror 309 and the focusing glass 310 and the fact that the aforementioned flange back can be accurately guaranteed, there is an improvement in finder focusing accuracy.

[Effects of the Invention] As explained above, by integrally molding the mirror hook with plastic as a holding member for optical components such as a pentaprism, which had conventionally been a separate structure, it is possible to replace the conventional metal mirror box. On the other hand, it can handle complex shapes with high precision, and it is also possible to reduce the weight, resulting in a significant cost reduction, and it has also become possible to solve the drawback of plastic mirror boxes, which is the lack of strength. Additionally, since the entire mirror hook is integrally molded, if the mold dimensions are controlled, adjustments that previously required adjustment, such as adjusting the mirror tilt, photographing focus, and viewfinder observation focus, can now be adjusted without the need for adjustment.

[Brief explanation of drawings]

Figures 1 and 2 are exploded perspective views of a camera as an example, Figure 3 is a sectional view in the optical axis direction, Figures 4 to 6 are views showing the mirror mounting section, and Figures 7 to 10. Figure 11 shows the superimpose in the finder, Figure 11 shows the mount mounting surface, Figure 12 shows a sectional view in the optical axis direction, Figure 13 shows the focus plate mounting part, and Figure 14 shows the mounting part of the focus plate. Figure 15 is a perspective view of the camera body, Figure 16 is a plan view from the rear, Figure 17 is a cross-sectional view along the optical axis with the lens attached, and Figure 18 is a diagram showing the illumination range on the focusing plate. FIG. 2 is a perspective view showing a conventional example. 501...Mirror hox body block 502...
Mirror unit 507...Shutter unit 511...Mount 30...Focusing glass 31...Penta prism 33...Light projection lens 34...LED "D9 East 15 Room Figure 13

Claims (3)

[Claims] (1) In a single-lens reflex camera incorporating a mirror box having a mounting seat for a photographic lens, a mirror mounting portion that supports a mirror for a finder optical system, and a mounting portion to the camera body, the photographic lens mounting seat and the A single-lens reflex camera characterized in that, in addition to the mirror mounting part and the main body mounting part, a mounting and holding part for an optical component for guiding the reflected light of the mirror to a viewfinder observation position are all integrally molded from plastic. (2) The single-lens reflex camera according to claim 1, wherein a focusing glass unit is used as the optical component. (3) The single-lens reflex camera according to claim 1 or 2, wherein a pentaprism is used as the optical component.