JPS6275426A - Diaphragm control device for single-lens reflex camera - Google Patents

Abstract

PURPOSE:To attain precise diaphragm control by connecting a detecting means for detecting the change of the aperture of a diaphragm of a diaphragm device electrically to an electronic control means arranged on the camera body side and controlling the driving and stop of the diaphragm of an interchangeable lens on the camera body side. CONSTITUTION:A partial gear 30d is formed on a part of the peripheral edge part of a stopping plate 30 and a small-diameter gear of a step gear 37 is engaged with the partial gear 30d. A driving gear 38 is engaged with a large- diameter gear of the step gear 37 and a slit forming member 39 is coaxially engaged with the gear 38. The slit forming member 39 is constituted by forming many cuts on a disk at equal intervals and the slit parts of the member 39 are held between a light emitting diode and a photodetecting element which are opposed to each other to constitute a photointerrupter 60. The output of the photointerrupter is inputted to a waveform shaping circuit 61. Consequently, the accuracy of diaphragm control of a single-lens reflex camera can be improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention provides: - an aperture control device for an eye reflex camera, specifically, an aperture control device in an interchangeable lens that automatically and appropriately controls the aperture in an interchangeable lens by means of a driving means on the camera body; This invention relates to an aperture control device.

[Prior Art] The most commonly used aperture control device for single-lens reflex cameras is (1) that uses the aperture aperture of an interchangeable lens as rotation angle position information of an aperture adjustment lever on the side of the lens. This is detected by the camera, and the aperture aperture of the lens is controlled by the aperture driving means and aperture setting means on the camera side. In addition, (2) a means for controlling the aperture by simply sending and receiving electrical signals between the camera and the camera by placing a stepping motor on the outer periphery of the lens barrel (see Japanese Unexamined Patent Publication No. 78132/1983), and (3) the lens mirror. An aperture control device (see Japanese Patent Laid-Open No. 56-42219) has also been proposed in which an electromagnetic drive means for driving an aperture and an electromagnet for determining an aperture diameter are provided on the outer periphery of a frame.

[Problems to be Solved by the Invention] By the way, in a single-lens reflex camera with interchangeable lenses, the aperture control means described in (1) above has a problem in that the positioning accuracy of the camera body mount and lens mount in the rotational direction is equal to the aperture aperture control accuracy. , which directly affects both mounts, requires highly viscous positioning members, which increases costs. In addition, since many levers and gears are used to transmit position information from the aperture member in the lens to the aperture detection means in the camera, errors due to their deformation, rattling, backlash, etc. It is difficult to detect the aperture value.

Furthermore, although the above aperture control means (2) and (3) are capable of accurate aperture control, - in the case of an eye reflex camera, which can be said to be a feature of the same camera, the number of I often use interchangeable lenses from books, so
If each lens is provided with a stepping motor or an electromagnetic drive mechanism, the total weight of the camera body and the plurality of interchangeable lenses increases, and the total cost also increases.

Therefore, an object of the present invention is to optimize the arrangement of the mechanisms provided for each of a plurality of interchangeable lenses and the mechanism provided within the camera body in order to eliminate the above-mentioned conventional drawbacks, thereby increasing the total cost and weight of the camera system. To provide an aperture control device for a single-lens reflex camera that can perform accurate aperture control without any need.

[Means and effects for solving the problems] In the device of the present invention, a detection means for detecting a change in the aperture diameter of an aperture device that performs an aperture operation when the camera body is driven intermittently is provided in the interchangeable lens. This detection means is electrically connected to electronic control means on the camera body, and the camera body controls the aperture drive and stop of the interchangeable lens.

[Example] The present invention will be explained below with reference to illustrated embodiments.

FIG. 1 is a perspective view of an aperture control device for a single-lens reflex camera showing a first embodiment of the present invention.

In FIG. 1, light that passes through a photographic lens (not shown) and passes through an aperture aperture enters the camera body, and is directed upward by a movable reflection mirror 22 installed obliquely at an angle of 45° on the photographic optical axis 0. The light is reflected by the beam, and is transmitted and diffused to the focusing screen 40. The optical image of this focusing screen 40 is formed by a pentaprism 41. It can be observed as an erect image in the finder through the eyepiece 42. Further, near the eyepiece lens 42, a photometric light receiving element 43 is arranged facing the exit surface of the pentaprism 41. Further, behind the movable reflection mirror 22, an aperture, focal brain shutter, etc. (not shown) are provided.

The light receiving element 43 for photometry measures the brightness of the subject by the release operation of the camera, and transmits the brightness information to a known CPU 5.
0 (see Figure 4). The CPU calculates the number of refinement steps ΔAv (apex calculation value) together with the determining factor information of the exposure conditions set in advance. after that,
Micromotor 1 is driven. A large-diameter spur gear 3a meshes with the output gear 2 of the motor that rotates in the direction of the arrow, and a bevel gear 3b is integrally provided with the gear 3a. 4a is engaged. A spur gear 4b is integrally attached to the bevel gear 4a, a large diameter gear of a stepped gear 5 is engaged with the spur gear 4b, and a set lever drive gear 6 is engaged with the small diameter gear.
are interlocking. Therefore, as the output gear 2 rotates in the direction of the arrow, each of the gears 3a+ 3b, 4a, 4b
and 5 rotate in the direction of the arrow to transmit power and rotate the gear 6 in the direction of the arrow. A protrusion 6a is integrally provided on the front surface of the drive gear 6, and engages with an interlocking pin 7a implanted on the rear surface of a gear 7, which is rotatably disposed coaxially with the drive gear 6. There is. A transmission gear 8 is meshed with the gear 7, and a gear 9a is meshed with the gear 8. A gear 9b is fixed coaxially with the gear 9a, and the gear 9b meshes with a gear portion 10a of an aperture ring 10 that rotates about the optical axis 0. Therefore, the rotation of gear 7 is caused by the rotation of gear 8. Gear 9a.

It is transmitted to the aperture ring 10 via 9b. A spring 11 is stretched between the aperture ring 10 and a stationary member (not shown) inside the camera, and a rotational force in the direction of the arrow is applied to the aperture ring 10.
In the initial state, due to the rotational force that is significantly reduced between the gear train connecting the gear part 10a and the gear part 10a, the protruding piece 10d is held in a magnetically stable position by the force of holding the motor 1 in a magnetically stable position, that is, the holding force due to so-called cogging. It is held at a position where it abuts against the stop pin 25. Further, in this rotational position, the aperture opening switch SW1 is closed by the protruding piece 10c extending from the aperture ring 10. When the gear 6 rotates in the direction of the arrow in this state, the interlocking pin 7a follows the projection 6a due to the elasticity of the spring 11, and the gears 7.8° 9a, 9b and the aperture ring 10 rotate in the direction of the arrow, and the aperture The open switch SWI is in an open state. 1 Further, a small diameter gear of a step gear 12 is engaged with the gear 8 in the camera body, and a pinion 13a that constitutes an aperture control member 13 is engaged with the large diameter gear.
a and the ratchet wheel 13b are integrated to form the diaphragm control member 13. And the ratchet wheel 13
A locking pawl 15b of the aperture locking lever 15 is adapted to engage and disengage from the position b.

The aperture locking lever 15 is formed of a vertically long lever, and is rotatably supported by a support shaft 15a at a fulcrum near the upper part thereof, and the locking pawl 15b is attached to the ratchet ring 13b in the middle. They are formed in opposing positions. A charging arm 15c is formed at the upper edge of this locking lever 15 and is bent toward the rear.
5c is in contact with the rigid arm portion 17a of the set lever 17.

This set lever 17 has its central fulcrum at the support shaft 15.
The arm 17b of the arm 17b is horizontal so as to behave elastically, and its tip extends onto the rotation path of the protrusion 6a, and the thin arm 17a is supported by the charge arm 15c. It extends below. An auxiliary spring 18 with weak elasticity is stretched between the tip and the stationary member.
Due to the tight elasticity of Hirao, the thin arm 17a becomes the charge arm 15.
It is in contact with c.

Further, an armature 19 that is attracted by a release type electromagnet 20 is pivotally supported at the lower part of the aperture locking lever 15, and when the armature 19 is attracted to the electromagnet 20, the aperture locking lever 15 is locked. The retaining pawl 15b is held at a position spaced apart from the ratchet ring 13b. As is well known, the release type electromagnet 20 has a permanent magnet 20a between the yokes around which the coils are wound.
It is a so-called combination magnet, which is configured by disposing a magnetic bypass section (not shown), and in an initial state, the aperture locking lever 15 is stretched between a stationary member (not shown) inside the camera body and the locking lever 15. Ta,
Separation spring 1 having a stronger elasticity than the spring 18
6 and is attracted to the electromagnet 20.

On the other hand, the back side of the gear 6 is shown in FIGS. 3(a) to 3(a).
As shown in c), a partially arcuate end cam 6b is formed, and when the gear 6 rotates and the diaphragm in the interchangeable lens, which will be described later, is narrowed down to the minimum aperture diameter, the end cam 6b is mirror driven. Actuation pin 2 fixed to lever 21
It serves to rotate the lever 21 around the support shaft 21a in the mirror-up direction (clockwise in FIG. 3(a)) via the lever 1c. The movable reflection mirror 22 is rotatably held around a support shaft 22a fixed to the upper part of both sides, and is lowered by a mirror down spring 23 and comes into contact with a mirror positioning pin 24 so as to be on the optical axis 0. It is installed diagonally at an angle of 45°. Further, a mirror drive bin 22b is fixedly planted on one side of the reflecting mirror 22, and when the mirror drive lever 21 is rotated clockwise, the bin 22b is pushed up by the upper side of the lever 21. A mirror raising operation is performed (see FIG. 3(C)). Then, at the mirror raising completion position, the bent portion 21b of the mirror drive lever 21 operates the mirror up switch SW2 from the off state to the on state. This switch S
When W2 is closed, the motor 1 stops, and at that time the mirror drive lever 21 is held at the mirror raising position at the top dead center of the end cam 6b of the gear 6.

The above is the aperture control mechanism disposed within the camera body.

Next, as shown in FIG. 1, the aperture diameter detection means and the aperture mechanism disposed in the interchangeable lens include a plurality of support bins 33a arranged at equal intervals around the optical axis O in an aperture case 33, which is a fixed member. The aperture blades 32 are pivotally supported on each support pin 33a through its support hole 32b. The aperture plate 30 that operates the aperture blades 32 is rotatably arranged around the optical axis 0, and the aperture plate 30 has a plurality of aperture cam grooves 3 of a known shape.
0b are bored, and drive pins 32a implanted in each of the proofing blades 32 are fitted into each of the cam grooves 30b. A bent arm portion 30a for connection is formed on a part of the outer periphery of the aperture plate 30 and extends along the optical axis 0 to the camera body, and this arm portion 30a and the lens barrel A weakly elastic spring 31 is stretched between a stationary member (not shown) inside. Therefore, when the interchangeable lens is attached to the camera body, the arm portion 30a is always in contact with the upper surface of the inwardly protruding piece 10b of the aperture ring 10 due to the spring 31. The shape of the aperture cam groove 30b depends on the rotation angle of the bent arm 30a and the drive bin 32.
The aperture diameter defined by a is formed in a proportional relationship.

A large number of striped patterns having different reflectances radially centering on the optical axis 0 are drawn on the protrusion 30c formed in a partial arc shape on the outer peripheral edge of the aperture cam plate 30. There is. A well-known reflective photoreflector 34 consisting of a combination of a light emitting diode and a light receiving element is arranged at a position facing this striped pattern, and its output is inputted to a waveform shaping circuit 35. In this example,
The amount by which the aperture is narrowed down is outputted from the photoreflector 34 as the amount of movement of the pattern on the protrusion 30'c, converted into a rectangular wave by the waveform shaping circuit 35, and outputted by the electrical connection contact 36a on the side of the lens as a digital pulse signal. be done.

Further, other electrical connection contacts 36b and 36C are power and ground contacts, which are respectively connected to electrical connection contacts 44a, 44b and 44c provided on the camera body, and the above-mentioned signals are manually transmitted to the CPU in the camera body. be done.

It goes without saying that the ground line may be a body ground using a lens frame, mount, or the like.

The aperture control device of the first embodiment is configured in this way.

Next, to explain its operation, Fig. 2(a) to Fig. 2(
Fig. 2(f) shows the operation of the aperture drive stop control mechanism extracted from Fig. 1, and Fig. 2(a) shows its initial state before photographing. In this embodiment, the narrowing operation is performed by rotating the gear 6 approximately 180' in the direction of the arrow from the initial state, and if the electromagnet 20 does not act during the narrowing operation, the narrowing operation can be performed from the open aperture state to the minimum aperture state. The mirror is then rotated by about 180 DEG to 300 DEG from the initial state to raise the mirror.

Now, when the release operation causes the motor 1 and the output gear 2 to rotate in the direction of the arrow, and the aperture ring 10 rotates in the direction of the arrow via the gear train, the aperture blades 32 start the aperture operation with this rotation, and the number of aperture stages increases. At the time when a number of pulse signals corresponding to ΔAv are generated from the photoreflector 34, a demagnetizing current is applied to the coil of the electromagnet 20 in the direction of attenuating the force that attracts the armature 19 according to a signal from the CPU, and the separation spring ' As the armature 19 separates from the electromagnet 20 due to the tightening elasticity of the diaphragm 16, the aperture locking lever 15 rotates counterclockwise around the support shaft 15a, and its locking pawl 15b engages the ratchet ring 13b.
jumps between the claws and suddenly stops the rotation of the diaphragm control member 13.
The aperture diameter is determined.

FIG. 2(b) shows a state in which the aperture aperture is determined to be approximately midway between the open and minimum apertures.

Further, since the motor 1 continues to rotate in the same direction thereafter, the follow-up engagement between the protrusion 6a and the interlocking pin 7a is released, and the gear 6 further rotates in the direction of the arrow. In addition, when the aperture is stopped down to the minimum aperture due to a very bright subject, etc., the protruding piece 10d is moved to the minimum aperture position regulating stop 26.
(See FIG. 1), the following engagement between the arrow tension projection 6a and the interlocking pin 7a is released, and the gear 6 similarly rotates in the direction of the arrow. As described above, when the gear 6 rotates from the initial state to about 180' to 300°, the mirror-up operation of the movable reflecting mirror 22 shown in FIGS. This is done by the action of the cam 6b.

During this mirror raising operation, the protrusion 6a of the gear 6 comes into contact with the horizontal arm 1'7b of the set lever 17, but since the lever 17 rotates counterclockwise while stretching the spring 18, as the gear 6 rotates, The engagement between the projection 6a and the horizontal arm 17b is released. Figure 2 (c) shows the protrusion 6 on the way up the mirror.
This shows a state in which the charging arm 15c and the narrow arm 17a are separated by the extension of the spring 18, and the contact between the protrusion 6a and the horizontal arm 17b is about to be released. Here, since the spring 18 is an extremely weak spring, the increase in the load on the motor due to the spring 18 at this time is extremely small.

When the movable reflective mirror 22 has been raised in this way and the mirror 2 is retracted from the photographing optical path, the mirror up switch SW2 is turned on, the motor 1 is stopped, and the gear 6 is turned on as shown in FIG. 3(C). In the state shown in FIG. 2(d), the protrusion 6a stops at a position separated from the horizontal arm 17b.

When the switch SW2 is turned on, the front curtain of the shutter starts, and the movement of the rear curtain of the shutter is controlled by the shutter speed control means. When the shutter trailing curtain finishes running, the motor 1 starts reversing. As a result, the gear train from output gear 2 to gear 6 operates, and each gear rotates in the direction opposite to the arrow shown in FIG. As a result, the mirror drive lever 21
The movable reflecting mirror 22 rotates counterclockwise due to the elasticity of the spring 23, and the movable reflecting mirror 22 descends until it comes into contact with the positioning pin 24. Further, the switch SW2 changes from the on state to the off state. On the other hand, the protrusion 6a comes into contact with the horizontal arm 17b again, and the spring 1
Since the thin arm 17a and the charge arm 15c are in contact with each other due to the tightening elasticity of the numeral 8, the aperture locking lever 15 is rotated clockwise around the support shaft 15a, and the locking pawl 15b is engaged with the ratchet ring 13b. The stopped state is released and the armature 19 is attracted to the electromagnet 20 again. Then horizontal arm 1
7b is elastically deformed, as shown in FIG. 2(e), and is released from contact with the protrusion 6a.

FIG. 2(f) shows the state immediately after the operating state shown in FIG. 2(e). A state in which the set lever 17 momentarily rotates counterclockwise against the elasticity of the spring 18 due to the repulsive energy stored by the elastic deformation of the horizontal arm 17b at the moment when the contact state between the protrusion 6a and the horizontal arm 17b is released. It is.

This operation ensures that the rear armature 19 and the electromagnet 20 are attracted to each other. To explain this in a little more detail, if the aperture locking lever 15 and the set lever 17 are integrally formed, the repulsive energy stored by the elastic deformation of the horizontal arm 17b will be transferred to the armature 1'9 and the electromagnet when it is released. This may act as a strong impact on the attraction surface of the electromagnet 20, causing the armature 19 to separate from the electromagnet 20. Therefore, in the present invention, the armature 1
9 and the electromagnet 20, the aperture locking lever 15 and the set lever 17 are formed separately, and a means for connecting them with a spring 18 having weak elasticity is adopted. There is.

With the armature 19 being attracted to the electromagnet 20 in this manner, the gear 6 continues to rotate in reverse, and the protrusion 6a and the interlocking pin 7a come into contact again, charging the spring 11 of the aperture ring 10 as shown in FIG. 2(a). Returns to the initial state shown in . Further, in conjunction with this, the aperture plate 30 is also reversed by the elasticity of the spring 31, and the aperture blades 32 are opened. Then, when the protruding piece 10d comes into contact with the stop pin 25, the protruding piece 10c
operates the aperture opening switch SW1 from off to on, stops motor 1, and returns the finder to the observation state. Subsequently, the film is wound and the shutter is charged by known means (not shown), and the camera returns to the next photographing preparation state.

Next, FIG. 4 is a block diagram of an electric circuit when performing programmed exposure control or automatic exposure control with shutter speed priority using the aperture control device of the first embodiment shown in FIGS. 1 to 3 above. This is what is shown.

In the case of program exposure control, subject brightness information Bv is sent from the subject brightness information detection circuit 51 including the light receiving element 43.
, film sensitivity information S■ from the film sensitivity information input means 52, and lens opening FN.

Lens opening FNo. information AVo is sequentially input to the CPU 50 from the information human power means 53. Then, the CPU 50 determines the number of narrowing stages ΔA based on a preset program.
and calculate the shutter time Tv.

In the case of shutter speed priority automatic exposure control, each information By from the luminance information detection circuit 51, film sensitivity information input means 52, and lens aperture FNo. information input means 53 is used.
, "'v" In addition to the input of vo, the CPU 50 receives the set shutter time information Tv from the shutter time setting means 59.
is input, and the CPU 50 calculates the number of refinement stages ΔA.

After calculating the aperture diameter, the CPU 50 outputs signals necessary for display to the display means 56. CP due to release operation
When a signal is output from U50 to the motor drive circuit 55,
The motor 1 is driven by the drive circuit 55 and starts driving the aperture and mirror. Along with this, a number of pulse signals corresponding to the change in the aperture diameter are output from the photoreflector 34 next to the lens, and the waveforms are shaped by the waveform shaping circuit 35 to the electrical connection contacts 36a-36c, 44a-
44c to the CPU 50. When the number of pulses corresponding to the number of aperture stages ΔAv is input, the CPU 50
A signal is output to the magnet drive circuit 54, and the release type electromagnet 20 performs aperture stop control.Furthermore, when the mirror up switch SW2 is turned from off to on due to mirror up completion, the CPU 50 outputs a stop signal to the motor drive circuit 55. Then, motor 1 stops operating.
A signal is output from 50 to shutter speed control means 57 to control the shutter operation.

After the trailing curtain of the shutter finishes running, a motor reversal signal is output from the CPU 50 to the motor drive circuit 55, and the motor 1 is rotated in reverse. Then, when the mirror up switch SW2 changes from the on state to the off state, the CPU 50 outputs a stop signal to the motor drive circuit 55, and the motor 1 stops reverse rotation.

Next, a signal is sent from the CPU 50 to the winding/shutter charge drive control means 58 to wind the film and charge the shutter, thereby completing the photographing.

In the above embodiment, the waveform shaping circuit 35 is provided inside the interchangeable lens, but it can easily be provided inside the camera body. Also, the open FN of the interchangeable lens.

In cameras that transmit various information such as information and focal length information from the lens to the camera body, one of the information transmission signal contacts between the lens and the camera body is time-shared to the lens aperture. Of course, it is also possible to use it for transmitting diameter-changing pulses.

Next, a second embodiment of the present invention will be described with reference to FIG.

The diaphragm control device of this second embodiment differs from the device of the first embodiment in the pulse signal generating means within the interchangeable lens.

That is, a sector gear, a so-called partial gear 30d, is formed on a part of the outer peripheral edge of the narrowing plate 30, and a small-diameter gear of a step gear 37 is engaged with the partial gear 30d. A drive gear 38 is engaged with the large diameter gear of the stepped gear 37, and a slit forming member 39 is attached to this gear 38.
are attached coaxially. The slit forming member 39 is a disc with many equally spaced cuts,
A photointerrupter 60 is provided in which a light emitting diode and a light receiving element face each other so as to sandwich the slit portion of the slit forming member 39fl. The output of this photointerrupter 60 is input to a waveform shaping circuit 61. The other structures inside the interchangeable lens and the structure around the camera body are exactly the same as those of the first embodiment. Therefore, a description of its configuration and operation will be omitted.

The feature of the device of this second embodiment is that the rotation angle of the diaphragm plate 30 is increased by the step gear 37, and the slit forming member 3
9, the aperture diameter formed by the aperture blades 32 can be detected as a digital pulse with higher accuracy. Further, the electric circuit of the device of the second embodiment is similar to the block diagram of FIG. 4 except that the photoreflector 34 is replaced with a photointerrupter 60 and the waveform shaping circuit 35 is replaced with 61. It is.

[Effects of the Invention] According to the present invention, the diaphragm drive source □ and the diaphragm stop control member, which greatly increase weight and cost, are disposed inside the camera body, and the diaphragm, which greatly affects the diaphragm control accuracy, is disposed within the camera body. Since the aperture detection means is placed inside the lens frame of the interchangeable lens, the total cost and weight of the camera system consisting of the camera body and multiple groups of interchangeable lenses are not increased, and extremely accurate single-lens reflex cameras can be used. A diaphragm control device can be provided.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an aperture control device for a single-lens reflex camera showing a first embodiment of the present invention, and FIGS. 2(a) to 2(f) show an aperture drive stop in FIG. 1 above. An enlarged front view showing the operating mode of the control mechanism, and FIGS. 3(a) to 3(c) are a side view, rear view, and operation of the mirror drive mechanism taken out from FIG. 1, respectively. Fig. 4 is an electric circuit block diagram of the aperture control device shown in Fig. 1 above, and Fig. 5 is a perspective view of the aperture control device of a single-lens reflex camera showing a second embodiment of the present invention. It is. 36a to 38c, 44a to 44c... Electrical connection contacts (electrical connection means) 50... CPU (electronic control means),
1 Wa 1 1 2 ≦ Plan 2 diagram (0) 5/'1 b Plan 2 district (b) Strategy 2 diagram (c) Ki 2 ip (d) Procedure amendment (voluntary) November 1985
Month/11 Special + i'l' Agency Director Uga Michibu-dono
] Go to 1. Indication of the incident 1985 Patent Patent No. 2
14230 No. 2, Title of the invention - Aperture control device 3 for an eye reflex camera, relationship to the case of the person making the correction Patent applicant location: 43-2, Hasgaya 2-chome, Shibuya-ku, Tokyo Name (037) Olympus Kogaku Kogyo Co., Ltd. 4, agent address: 5-J-1 Matsubara, Taya-ku, Tokyo 11
No. 152, No. 14, No. 5, Subject of amendment: ``Detailed Description of the Invention in the Specification'' and ``Drawings'' system. 1) ``Mirror-up switch'' described from line 18 to line 19 on page 20 of the specification. Correct "SW2 goes from on to off" to "Aperture opening switch SWI goes from off to on." (2) Figure 2 (f) in the drawing attached to the application is corrected to the attached drawing.

Claims (1)

[Scope of Claims] In a single-lens reflex camera in which an aperture operating means of an interchangeable lens is driven by a drive means on the camera body, a detection means for detecting a change in aperture diameter provided in the interchangeable lens; A means for electrically connecting the detection means and an electronic control means on the camera body; and an aperture stop means provided on the camera body and actuated by a signal from the electronic control means. Aperture control device.