JPS6331048Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to optical accessories such as interchangeable lenses that can be attached to a single-lens reflex camera body.

[Background of the invention] As a means of attaching and detaching between a camera body and an interchangeable lens as an optical accessory, the mounts of the camera body and the interchangeable lens are rotated clockwise or counterclockwise to couple and detach. A removable bayonet mount is used.

Around the mount, there is a positioning fixing member that fixes the position between the camera body and the interchangeable lens when the lens is attached, an aperture actuation mechanical interlocking means that transmits drive from the camera body side to the interchangeable lens side, and a mechanism that connects the lens side to the camera body side. Various components that exchange mechanical and electrical signals between the camera body and the interchangeable lens are concentrated, such as the aperture step number interlocking means and the open aperture value interlocking means, which transmit information to the mount. This has led to a very complicated situation.

Under the above circumstances, recent cameras
With the addition of the AF function, it has become necessary to electrically exchange a large amount of information between the camera body and lens, so the number of electrical connection terminals has increased further, and the arrangement and configuration of the terminals near the mount has changed. has become increasingly involved in the reliability and structure of

[Purpose of the invention] The purpose of this invention is to provide optical accessories such as interchangeable lenses that can increase the mirror length and viewfinder field of view even when the number of electrical connection terminals is increased, and also shorten the flange back and back focus. The aim is to provide products.

[Summary of the invention] The present invention has a bayonet mount-type optical accessory mount claw that can be connected and detached by rotating around the optical axis with respect to the camera body side mount claw, and has multiple camera body side mount claws. For a single-lens reflex camera body, which has electrical connection terminals arranged around the optical axis and a mirror that reflects subject light to the viewfinder optical system,
In the attachable optical accessory, when the claw of the optical accessory mount is rotatably connected to the claw of the camera body mount, a plurality of optical accessories are provided at positions where the claw comes into contact with the electrical connection terminal on the camera body side. This electrical connection terminal on the optical accessory side is located below the center of the optical axis when the two mounts are coupled, and near the inner diameter side of the abutting surface of the optical accessory side mount. The present invention is characterized by an optical accessory disposed substantially along the axial direction and protruding rearward in the optical axis direction from the position of the claw of the optical accessory side mount.

[Embodiments of the invention] Examples of the invention will be described below with reference to the drawings.

This example is an optical accessory attached to a camera that uses a rotatable bayonet mount that connects the camera body side mount and lens side mount by rotating in one direction and detaching them by rotating in the other direction. This is applied to interchangeable lenses as products.

Camera body side mount 1 as shown in Figure 1.
has an annular abutment surface 1A centered on the optical axis O,
There are three claws 1C ₁ , 1 on the inner peripheral side of this abutment surface 1A.
C ₂ and 1C ₃ are formed in a distributed manner. FIG. 1 shows the camera body mount 1 viewed from the front side of the camera, and in the figure, a mount lock pin 2 is arranged in the vicinity of the immediate right side of the abutment surface 1A. As shown in FIG. 5, this mount lock pin 2 protrudes from the abutting surface 1A of the camera body side mount 1 due to the biasing force of a spring 24 placed at an appropriate position in the mirror box 4, and when the mount is fully installed, the mount lock pin 2 protrudes from the abutting surface 1A of the camera body side mount 1, and when the mount is fully attached, the mount lock pin 2 protrudes from the abutting surface 1A of the camera body side mount 1. It engages with the mount lock groove 6 of the mount 5, but when the unlock button 25 is pushed toward the front cover 22 side against the urging force of the spring 26, the unlock button 25 engages with the lock lever 23 integrated with the mount lock pin 2. Therefore, the mount lock pin 2 is retracted toward the camera body (upward in FIG. 5), and the above-mentioned engaged state is released.

On the other hand, the lens side mount 5 also has an annular abutment surface 5A centered on the optical axis O, as shown in FIG. Three claws 5C ₁ , 5C ₂ , and 5C ₃ are formed in a distributed manner to engage with 1C ₁ , 1C ₂ , and 1C _{3 ,} respectively. Figure 2 shows the lens side mount 5 viewed from the rear end side of the lens with the lens fully attached to the camera body. When viewed from the front, a mount lock groove 6 is carved in the peripheral area near the right side.

A plurality of camera-side electrical connection terminals 3A and lens-side electrical connection terminals 7A, which form pairs with each other, are provided in the lower peripheral area of the camera body side mount 1 and the lens side mount 5 on the inner diameter side of the abutting surfaces 1A and 5A. are arranged along the direction around the optical axis, and when the mounting is completed, the corresponding terminals 3A,
7A are now facing each other. These terminals 3A and 7A are for exchanging various signals between the camera body side circuit and the lens side circuit. For example, power is supplied from the power supply installed on the camera body side to the lens side, It is used to input the aperture f-number and focal length information unique to each lens stored in the ROM on the camera body to the CPU (central processing unit) on the camera body.

In FIGS. 1 and 2, 3 and 7 are the camera-side terminal block and lens-side terminal block to which the terminals 3A and 7A are attached, respectively, and are shaped like an arc along the inner periphery of each mount abutting surface 1A, 5A. None, and its arrangement is at a position retracted downward from the rectangular picture frame of the mirror box 4. Therefore, it is easy to ensure an effective luminous flux. In addition, the circuitry of the AF unit 18 (including the optical sensor and control circuit), which is normally placed at the bottom of the camera body 9 and is closely related to the connection terminals, can be easily connected to the flexible printed board 19 without interfering with other components. Can be connected.
Each of the terminals 3A and 7A is given an appropriate size and spacing to prevent non-contact or erroneous contact due to mount play or component dimensional errors when the mount is completed.

6 and 7 show detailed structures of the terminals 3A and 7A.

FIG. 6 is a sectional view showing a state in which the mount is being attached, and 3 is a camera-side terminal block, and 3A ₁ to 3A ₇ are camera-side electrical connection terminals having pin-like tips. terminal 3
B ₁ to 3B ₇ are camera side terminal springs, and the springs 3B ₁ to 3B 7 are camera side terminal springs.
3B ₇ connects the terminals 3A ₁ to 3A ₇ upward (Fig. 6,
7), and as a result, the tips of the terminals 3A ₁ to 3A ₇ protrude upward from the outer surface of the terminal block 3 in the figure. The lower position of the terminals 3A ₁ to 3A ₇ has the corresponding terminal 3A ₁
A flexible printed board 19 electrically connected to 3A ₇ is arranged. Reference numeral 7 designates a lens-side terminal block, and pin-shaped lens-side electrical connection terminals 7A ₁ to 7A ₇ having a large diameter portion on the lower side are embedded in the terminal block 7 . The upper portions of the terminals 7A ₁ to 7A ₇ are electrically connected to the flexible printed board 21 . A chamfered portion is formed at both lower ends of the terminal block 7, and the terminal 3
The contact resistance with A ₁ to 3A ₇ is reduced. If the lens side terminal block 7 is moved in the direction of arrow A from the state shown in FIG. 6, the terminals 3A ₁ to 3A ₇ will be pushed downward against the biasing force of the springs 3B ₁ to 3B ₇ .
Finally, the mount attachment complete state shown in FIG. 7 is reached. In this state, since the upper and lower terminals 7A ₁ to 7A ₇ and 3A ₁ to 3A ₇ match, accurate signal transmission is performed. At this time, since the mount lock pin 2 is engaged with the mount lock groove 6 as described above, the locked state is maintained.

In FIG. 3, the reference numeral 9 indicated by a two-dot chain line indicates the camera body, and the light _L1 that has passed through the rear lens element 8 is reflected upward by the main mirror 10, passes through the finder screen 14 and the pentaprism 15, and passes through the eyepiece lens ( (not shown). On the other hand, the light L ₂ that has passed through the main mirror 10 is reflected downward by the sub-mirror 12 and is located at the bottom of the mirror box 4.
The signal is sent to the AF unit 18. Here, 11 is a main mirror receiving plate, 13 is a submirror receiving plate, 16 is a viewfinder receiving plate, and 17 is a spacer. The end surface (i.e., mutual contact surface) of the lens side electrical connection terminal 7A in the optical axis direction is the rear end surface 5 of the lens side mount 5.
It is set to a position closer to the camera body 9 side (film surface side) than D and the claw 5C, that is, to protrude rearward in the optical axis direction. As shown in FIG. 3, when the lens is attached, the claw 1C of the camera body side mount 1 and the claw 5C of the lens side mount 5 are engaged, and at the same time the camera side electrical connection terminal 3A is connected to the lens side electrical connection terminal. It is in contact with the connection terminal 7A. 20 is a lens-side circuit element including a CPU with a built-in ROM, and 21 is a flexible printed board that connects the circuit element 20 and the lens-side electrical connection terminal 7A. Since the lens side terminal block 7 protrudes from the lens rear lens end surface 8A toward the camera body 9 side, that is, toward the rear in the optical axis direction, the lens and camera body are separated and the mount side of the lens is facing downward, as shown in FIG. Even when the rear end surface 8A of the rear lens element is placed in a flat position, the rear end surface 8A of the rear lens does not come into contact with the mounting surface 27 and is not damaged. Further, the lens-side electrical connection terminal 7A protrudes from the camera body 9 side, that is, rearward in the optical axis direction, than the claw 5C of the lens-side mount, so that when the lens is attached, the mount claw 5C Do not come into contact with it and cause damage.

As explained above, in this embodiment, the lens side electrical connection terminal 7A is located below the optical axis center and near the inner diameter side of the abutment surface 5A when both mounts are connected, specifically, there is a large margin of space. Since it is located in the lower peripheral area of the mirror box 4, which can be removed, an effective luminous flux can be secured even though the number of terminals is increased. In addition, this terminal 7A can be easily connected to the circuit of the AF unit 18 using a flexible printed board, etc., without interfering with other circuits.
Furthermore, since there is plenty of space, there is a large degree of freedom in designing the connection terminals.

In this embodiment, since the lens-side electrical connection terminal 7A is made to protrude rearward in the optical axis direction beyond the position of the claw 5C of the lens-side mount 5, the camera-side electrical connection terminal 3A may be attached to the lens by mistake. There is no need to worry about damage caused by the claws 5C of the side mount 5 or electrical accidents caused by abnormal contact. or,
Even if a single interchangeable lens is placed carelessly, the lens surface can be protected from direct contact with other objects. Also, the lens side electrical connection terminal 7A
Protruding means that the camera-side electrical connection terminal 3A is inevitably placed behind the mount position (more precisely, the mount mating surface 1A position) in the optical axis direction, which makes it difficult to attach the interchangeable lens. Even when it is removed, it will not be damaged by contact with other objects, and furthermore, even if the camera-side electrical connection terminal 3A is a movable type as shown in the example, it is in a position that is difficult to touch, so it can be easily moved. There is no fear of external pressure being applied that would make things worse.

In this embodiment, the lens-side electrical connection terminal 7A is made to protrude behind the optical axis from the claw 5C of the lens-side mount 5, and is positioned substantially inside the camera body when both mounts are connected. Since it is located below the center of the optical axis and near the inner diameter side of the abutment surface 5A, the flange back and back focus can be shortened, and lenses with the same aperture ratio can be housed in a compact mount diameter. In other words, the position below the optical axis center and near the inner diameter side of the abutting surface 5A is a position where the tip trajectory of the main mirror 10 escapes toward the film surface side, so the main mirror 10 is located at the rear end of the lens or at the lens side mount 5. Claw 5C
It can be extended to the very edge of the rear end, reducing mirror breakage, and since there is nothing that interferes with the placement space of the viewfinder screen 14, the screen 14 can be enlarged and the high field of view viewfinder can be installed on the camera itself. This can be achieved without increasing the size. Also, since the rear lens element 8 can be brought closer to the film surface inside the camera body, the flange back and back focus can be shortened, and the mount itself can also be brought closer to the film surface inside the camera body, making it possible to maintain the same aperture. It is possible to fit a comparable lens into a compact mount diameter. In other words, a large-diameter lens can be designed with a compact mount, and as shown in FIG.
Even if a lens is made, it is possible to design a lens in which only the lens side terminal block 7 is cut out. For reference, suppose that the lens-side electrical connection terminal 7A is retracted close to the abutment surface 5A. Therefore, only a lens with a certain amount of light can be designed, which is disadvantageous in terms of securing an effective luminous flux.

In this embodiment, since the lens side electrical connection terminal 7A is arranged near the inner diameter side of the abutment surface 5A,
This prevents water, dust, etc. from entering the terminal 7A position to some extent, and also prevents abrasion particles between the mount surfaces from getting on the terminal 7A, and prevents the terminal 7A from sliding against the metal surface of the mount. It does not move and wear out, and furthermore, the strength of the mount itself is not impaired.

[Effects of the invention] As explained above, the present invention provides an optical accessory that can increase the mirror length and viewfinder field of view even when the number of electrical connection terminals is increased, and further shorten the flange back and back focus. were able to provide the goods.

[Brief explanation of the drawing]

Figure 1 is a front view of the camera body side mount seen from the front side, Figure 2 is a rear view with the lens side mount attached, Figure 3 is a longitudinal sectional view of the center of the camera with the lens attached, and FIG. 4 is a partial sectional view showing the state in which the lens is placed, FIG. 5 is a partial sectional view showing the positioning mechanism, and FIG. 6 is a sectional view showing the state of the connection terminal while the lens is being attached.
FIG. 7 is a sectional view showing the state of the connection terminal after the lens has been attached. 1... Camera body side mount, 1A... Matching surface, 1C ₁ to 1C ₃ ... Claw, 2... Mount lock pin, 3... Camera side terminal block, 3A ₁ to 3A ₇ ...
Camera side electrical connection terminal, 3B ₁ to 3B ₇ ... Spring,
4...Mirror box, 5...Lens side mount, 5A...Abutment surface, 5C ₁ to 5C ₃ ...Claw, 6...
...Mount lock groove, 7...Lens side terminal block, 7
A ₁ ~ 7A ₇ ... Lens side electrical connection terminal, 8 ...
Rear lens element, 9...Camera body, 10...Main mirror, 11...Main mirror receiving plate, 12...Submirror, 13...Submirror receiving plate, 14...Finder screen, 15...Penta prism, 16
...Finder holder, 17...Spacer, 18...
...AF unit, 19...Flexible printed board, 20...Circuit element.

Claims (1)

[Claims for Utility Model Registration] A bayonet mount type optical accessory mount has a bayonet mount claw that can be connected and detached by rotation around the optical axis with respect to the camera body mount claw, and multiple camera body side mount claws. An optical accessory that can be attached to a single-lens reflex camera body, which has electrical connection terminals arranged around the optical axis and a mirror that reflects subject light to a viewfinder optical system, wherein the camera body A plurality of electrical connection terminals on the optical accessory side are formed at positions where the claws on the optical accessory side mount come into contact with the electrical connection terminals on the camera body side when the claws on the optical accessory side mount are rotatably connected to the claws on the side mount. The electrical connection terminal on the accessory side is disposed below the center of the optical axis when both mounts are coupled, and near the inner diameter side of the abutting surface of the optical accessory mount, approximately along the direction around the optical axis. The optical accessory is also characterized in that the optical accessory side mount is protruded rearward in the optical axis direction beyond the position of the claw of the optical accessory side mount.