JPH0277045A - Device for confirming depth of single-lens reflex camera - Google Patents

Abstract

PURPOSE:To confirm depth by the use of a mirror electrically driving mechanism by reversely rotating a motor with a reverse rotation signal from a preview reset switch and stopping the motor when a cam gear for a mirror and a cam gear for a shutter and a diaphragm return to initial dormant positions. CONSTITUTION:By turning on the preview reset switch 85, the motor 12 is reversely rotated and the cam gear for the mirror 26 and the cam gear for the shutter and the diaphragm 27 are reversely rotated. When a preview rotation angle detecting switch 80 detects that the cam gear for the mirror 26 and the cam gear for the shutter and the diaphragm 27 return to the initial dormant positions, a motor control circuit 83 outputs a motor stopping signal. Therefore, a diaphragm linkage plate 36 ascends to the height corresponding to a stop value decided by a diaphragm control mechanism and a lens is stopped down to a set stop value. Thus, the depth by the set stop value can be surely confirmed even in a program mode.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to a single-lens reflex camera whose mirror is driven by a motor, and particularly to a depth confirmation device using a motor.

"Prior Art and its Problems" In the conventional depth confirmation device (preview device) of a single-lens reflex camera, the photographer mechanically narrows down the depth using a manual lever. However, since the diaphragm is normally biased in the opening direction with a relatively large force, it is a burden to operate the manual lever against this biasing force, and it is even more difficult to maintain the diaphragm in a closed state for a long time. It is. Cameras equipped with a mechanism for holding the aperture position are also known, but they require a reset operation and are undeniably difficult to set and reset.

On the other hand, mechanisms in which the mirror is driven by a motor are becoming common, especially in high-end eye reflex cameras. This mirror electric drive device basically supports a gear train and a mirror box mechanism driven by the rotation of this gear train on the side surface of the mirror box, and this gear train is rotationally driven by a motor. Therefore, the mirror box mechanism generally performs a series of operations including closing down the lens, raising the mirror, releasing the mechanical lock of the electromagnetic shutter, lowering the mirror after the shutter has moved, and releasing the stopping down of the lens.

``Object of the Invention'' An object of the present invention is to obtain a depth confirmation device that can confirm depth by using this mirror electric drive mechanism. That is, an object of the present invention is to provide a device that can perform depth confirmation by driving an electric motor by operating an electric switch member.

``Summary of the Invention'' The present invention generally provides a mirror electric drive mechanism for an eye-reflex camera, in which a mirror cam gear and a shutter are mounted in a mirror box, each of which is driven one rotation from an initial rest position by the normal rotation of a motor when the shutter release is released. A diaphragm cam gear is provided, and after the diaphragm is narrowed down to a predetermined value by rotation of the shutter/diaphragm cam gear, the shutter can be operated, and then by rotation of the mirror cam gear,
Focusing on the fact that the mirror is retracted from the optical path and then returned after the shutter is operated, if the mirror cam gear and the shutter/diaphragm cam gear are rotated forward by an appropriate angle and then reversed, the mirror and shutter can be removed. It was completed after discovering that it was possible to confirm the depth without operating (related members).

That is, the present invention provides a single-lens reflex camera equipped with the above-mentioned mirror electric drive mechanism, after the mirror cam gear and the shutter/aperture cam gear start rotating from the initial rest position.
A rotation angle detection means that detects the Brevigny rotation position that operates the aperture but does not operate the shutter and mirror, a preview switch separate from the release switch that issues a forward rotation signal to the motor, and a forward rotation signal from this preview switch that causes the motor to rotate. a motor control circuit that starts normal rotation of the motor and stops the motor when the rotation angle detection means detects a preview rotation position; and a preview reset switch that issues a reverse rotation signal to the motor after the motor is stopped; The control circuit further reverses the motor by a reverse signal from the preview reset switch.
It is characterized in that the motor is stopped when the mirror cam gear and the shutter/diaphragm cam gear return to their initial rest positions.

The stop signal after the motor is reversed can be obtained by the rotation angle detection means, but it may also be obtained by the origin (initial rest position) detection means of the mirror cam gear and the shutter/diaphragm cam gear.

The preview switch and preview reset switch are
Although they may be provided separately, it is possible to configure them by different switch states of a single switch.

"Embodiments of the Invention" The present invention will be described below with reference to illustrated embodiments. As shown in FIG. 6, the mirror box 11 located approximately in the center of the front of the camera body 13 has a main plate 14 and a bottom plate 15 on both sides. A box mechanism 20 is provided. The motor 12 is provided at the top of the mirror box mechanism 20 with its output shaft 16 perpendicular to the main plate 14 . The location of this motor 12 is above the spool and sprocket chamber.

1 and 2 are side views of the mirror box mechanism 20 driven by the motor 12 in the direction of arrow I in FIG. Main board 1
An auxiliary main plate 21 is fixed to the outer surface of the motor 4 at a constant pressure distance, and a motor 12 is fixed to the upper end of the auxiliary main plate 21. The pinion 22 fixed to the output shaft 16 of the motor 12 and the gear train that meshes with the pinion 22 are attached to this main plate 1.
4 and the auxiliary main plate 2I so as to be rotatable. This gear train consists of double gear 23.24, idle gear 25
, a mirror cam gear 26, and a shutter/aperture cam gear 27. The mirror cam gear 26 and the shutter/diaphragm cam gear 27 have the same number of teeth, and each gear of 0 or more is composed of an inexpensive spur gear.

A mirror cam 28 is integrally fixed to the mirror cam gear 26, and this mirror cam 28 is attached to the main plate 14 with a shaft 2.
9 engages with a follower roller 31 of a mirror drive lever 30 rotatably mounted. In FIGS. 1 and 2, the mirror cam 28 is shaded to make its shape easier to understand. A push-up pin 34 that engages with the tip of the mirror drive lever 30 is fixed to the mirror 33 that is pivotally connected to the main plate 14 by a shaft 32.
When rotated upward clockwise in the figure, the mirror 33 rises. The timing for raising and lowering the mirror 33 is determined by the timing at which the mirror cam 28 pushes up the mirror drive lever 30 via the follower roller 31.

A shutter cam 36 and an aperture cam 37 are integrally fixed to the shutter/diaphragm cam gear 27.

The shutter cam 36 is connected to the auxiliary main plate 21 (main plate 14
) is engaged with a follower roller 40 of a shutter set lever 39 which is pivotally connected to the shutter set lever 39 . The shutter set lever 39 rotates downward when the shutter cam 36 rotates clockwise in FIG. 2 and its cam surface retracts.
The mechanical lock of the electromagnetic focal plane shutter is released, allowing the vehicle to travel.

The aperture cam 37 is connected to the auxiliary main plate 21 (main plate main plate 14
) The follower roller 44 of the diaphragm drive lever 43 is pivotally mounted on the
engage with. Further, an aperture linking plate 46 is supported on the main plate 14 so as to be movable a certain distance in the vertical direction by a guide shaft 45 and the above-mentioned shaft 29, and an interlocking bin 47 is fixed to the lower end of this aperture linking plate 46. There is. The interlocking pin 47 is engaged with the tip of a strong torsion spring 48 provided at the tip of the aperture drive lever 43.
3 is in the lowered position as shown in FIG.
6 in the lowered position. The aperture drive lever 43 is biased to rotate upward by a tension spring 49, that is, in a direction in which the follower roller 44 is in constant contact with the aperture cam 37, and the aperture linking plate 46 is also raised by a tension spring 50. biased in the direction. Therefore, when the aperture drive lever 43 is rotated in the upward direction by the aperture cam 37 and the torsion spring 48 is separated from the interlocking pin 47, the aperture linking plate 46 is raised.

The aperture linking plate 46 is integrally provided with an aperture driving protrusion 52, and this aperture driving protrusion 52 is constantly engaged with an aperture bin 53 connected to the aperture mechanism on the lens side, thereby preventing the aperture linking plate 46 from rising. The position determines the calibration value of the lens.

Reference numeral 54 denotes a tension spring that constantly engages the aperture driving protrusion 52 and the aperture pin 53. The raised position of the aperture linking plate 46 is determined by the aperture control mechanism 60 of the automatic exposure control device, with which the bifurcated portion 46a engages. This aperture control mechanism 60
4 will be explained. 3 corresponds to FIG. 1, and FIG. 4 corresponds to FIG. 2.

The main plate 61 of the aperture control mechanism 60 has a sector gear 6 connected to it by a shaft 62.
3 is pivotally mounted, and from this sector gear 63 to the tooth surface 63
A linking roller 64 provided on an arm 63b extending on the opposite side of a is engaged with the bifurcated portion 46a of the aperture linking plate 46.

The sector gear 63 meshes with a small diameter gear 66a of a double gear 66 pivotally connected to the main plate 61 by a shaft 65, and this double gear 6
The large-diameter gear 66b of No. 6 meshes with a slit disk 68 of a pulse generator (photointerrupter) 67. The slit disk 68 has light-transmitting slits 69 at equal angular intervals on its periphery, and the light-transmitting slits 69 and a photointerrupter 70 having a light projector and a light receiver sandwiching the light transmitting slits 69 provide the following effects:
A pulse generator 67 is configured.

With the above configuration, when the throttle linking plate 46 rises from the position shown in FIGS. 1 and 3, the sector gear 63 and the double gear 66
The slit disk 68 of the pulse generator 67 rotates through the rotation angle, and pulses corresponding to the rotation angle are sent to the photointerrupter 70.
taken from. This number of generated pulses corresponds to the raised position of the aperture link plate 46, and the comparison value is
Since this corresponds to the rising position of , the calibration value can be determined by managing this number of pulses.

A locking mechanism 71 is supported on the main plate 61 to stop the rotation of the slit disk 68 when the aperture linking plate 46 rises to a set comparison value. This locking mechanism 7
1, a claw member 72 having a locking claw 72a that engages and disengages with a locking tooth 68a on the circumferential surface of a slit disk 68 is attached to the main plate 61 with a shaft 73.
The interlocking arm 72b of the claw member 72 is engaged with the reciprocating plunger 74a of the locking magnet 74. In the de-energized state of the locking magnet 74, the claw member 72
The locking pawl 72a is separated from the locking tooth 68a of the slit disk 68, but when the locking magnet 74 is excited, the reciprocating plunger 74a advances and the locking pawl 72a meshes with the locking tooth 68a. The rotation of the slit disk 68 is stopped.

Therefore, when the pulse generator 67 counts the number of pulses corresponding to the calibration value predetermined by the exposure control device, the set calibration value is obtained by exciting the locking magnet 74.

Reference numeral 76 denotes a return lever provided on the claw member 72 with a shaft 77, which is connected to the aperture control mechanism reset bin 43a provided on the aperture drive lever 43.
In cooperation with this, the aperture set as described above is released. That is, when the diaphragm linking plate 46 is raised and then lowered, the diaphragm drive lever 43 rotates clockwise in FIG. 2.

At this time, the diaphragm control mechanism reset bin 43a rotates the claw member 72 counterclockwise in FIG. On the other hand, when the diaphragm control mechanism reset bin 43a rises from the state shown in FIG. I won't let you.

A rotation angle detection switch 80 is provided between the mirror cam gear 26 and the main plate 14 or the auxiliary main plate 21 to detect the preview rotation position. This rotation angle detection switch 8
0, the diaphragm drive lever 43 is operated after the mirror cam gear 26 and the shutter/diaphragm cam gear 27 start rotating in the normal rotation direction from the initial rest position shown in FIG. (mirror drive lever 30) is rotated at an angle at which it is not operated (rotation angle shown in Figure 2)
It is made up of a brush 81 and a land plate 82 having a land with which this brush 81 comes into contact. This rotation angle detection switch 80 also detects the initial rest position of the mirror cam gear 26 and the shutter/diaphragm cam gear 27.The detection signal of the 0 rotation angle detection switch 80 is as follows.
These input signals are input to the motor control circuit 83, and the motor control circuit 83 controls forward and reverse rotation of the motor 12 based on these input signals. Note that the initial rest positions of the mirror cam gear 26 and the shutter/diaphragm cam gear 27 may be detected by separate origin detection switches.

The present invention further includes a Brevigny 84 and a preview reset switch 85, and the motor 12 can be rotated in forward and reverse directions.

The mirror box mechanism 20 configured as described above operates as follows during normal photographing. When the shirt release signal is output, the motor 12 is driven in the forward rotation direction, and the pinion 22,
Via the double gears 23, 24 and the idle gear 25, the mirror cam gear 26 and the shutter/diaphragm cam gear 27 rotate one revolution from the initial rest position shown in FIG. During this rotation, first, at the beginning of the rotation of the shutter/diaphragm cam gear 27, the diaphragm drive lever 43 rises, and the diaphragm linking plate 46 rises to the position determined by the diaphragm control mechanism 60. That is, when the diaphragm linking plate 46 rises, the photointerrupter 70 counts pulses according to the distance it rises, and when the counted pulse number reaches the number of pulses corresponding to the set calibration value, the locking magnet 74 is excited and the slit is closed. The rotation of the disc 68 is stopped. When the rotation of the slit disk 68 stops, the aperture linking plate 46 can no longer rise, and the aperture pin 53 moves together with the aperture driving protrusion 52.
The aperture of the lens is narrowed down to the predetermined value.

As the shutter/throttle cam gear 27 further rotates, the shutter set lever 39 descends, the electromagnetic focal plane shutter is mechanically unlocked, and the shutter membrane becomes movable.

On the other hand, when the mirror cam gear 26 rotates, the shutter
After the narrowing down is completed by the rotation of the squeeze cam gear 27 and the electromagnetic shutter is mechanically unlocked, the mirror cam 28 pushes up the mirror drive lever 30 to raise the mirror 33. When the mirror 33 has finished rising, the shutter moves, and when the movement is completed, the mirror drive lever 30 and the mirror 33 are lowered. Further, due to the rotation of the shutter/diaphragm cam gear 27, the aperture drive lever 43, the aperture linking plate 46, and the shutter set lever 39 return to the initial rest position shown in FIG. 1, and the lens returns to its open state.

In this way, in normal release operation, the mirror cam gear 26 and the shutter/diaphragm cam gear 27 are
It makes one rotation in the forward rotation direction from the rest state shown in the figure.

On the other hand, when confirming the depth, the following operation is performed according to the time chart shown in FIG.

Simply put, when the preview switch 84 is turned on, the mirror cam gear 26 and the shutter/diaphragm cam gear 27 rotate forward from the initial rest position shown in FIG. 1 to the preview rotation position shown in FIG. By turning on the reset switch 85, the mirror cam gear 26 and the shutter/diaphragm cam gear 27 change from the state shown in FIG. 2 to the first position.
This is an operation that reverses to the state shown in the figure.

First, when the preview switch 84 is turned on, the motor 12
rotates in the normal direction, and the mirror cam gear 26 and the shutter/diaphragm cam gear 27 rotate in the normal direction. When the rotation angle of the mirror cam gear 26 reaches the state shown in FIG.
detects this, and the motor control circuit 83 issues a stop signal to the motor 12. The state shown in FIG. 2 is a position where the diaphragm drive lever 43 rotates counterclockwise as shown in FIG. .

Therefore, the diaphragm linking plate 46 rises to a height corresponding to the calibration value determined by the diaphragm control mechanism 60, and the lens is stopped down to the set calibration value, so that the progress can be confirmed. This sequence is exactly the same as the sequence up to aperture determination during normal photography, so even in the program mode, the depth based on the set comparison value can be reliably confirmed. In the state shown in Fig. 2, the mirror cam gear 2
The mirror cam 28 of No. 6 does not contact the follower roller 31 of the mirror drive lever 30, so the mirror 33 does not operate. Also, the shutter cam 36 is connected to the shutter set lever 39.
is held in the raised position, so the shutter does not operate.

In this preview state, when the preview reset switch 85 is turned on, the motor 12 is reversely rotated, and the mirror cam gear 26 and the shutter/diaphragm cam gear 27 are reversely rotated. When the rotation angle detection switch 80 detects that the mirror cam gear 26 and the shutter/diaphragm cam gear 27 have returned to their initial rest positions, the motor control circuit 83 issues a motor stop signal. Everything thus returns to the initial rest position of FIG. In other words, shutter/throttle cam gear 2
7, the aperture driving lever 43 and the aperture linking plate 46 are lowered, and the aperture of the lens is also returned to its open state. Note that the preview switch 84 and the preview reset switch 85 may be constructed from separate operating members or may be constructed from the same operating member.

The mirror box mechanism 20 described above shows an example of a specific structure, and it is clear that the present invention is not limited to this structure. In short, in the mirror box electric drive mechanism, the mirror cam gear and the shutter/diaphragm cam gear can be rotated part way without making one revolution to enable previewing, and then reversed to return them to their original positions. That's fine. Furthermore, the recording medium of an eye reflex camera does not matter. That is, the present invention is applicable not only to silver salt photographic cameras but also to still video cameras.

"Effects of the Invention" As described above, the depth confirmation device for a single-lens reflex camera of the present invention includes Brevigny rotation angle detection means for the mirror cam gear and the shutter/diaphragm cam gear, which operates the aperture but does not operate the mirror and shutter. Depth can be checked by rotating the motor in forward and reverse directions by operating the preview switch and preview reset switch, making it extremely easy to check the depth with a small amount of operating force, and even in program mode. You can check the depth. Further, since there is no mechanical interlocking mechanism between the operating member and the diaphragm mechanism, there is a degree of freedom in the installation positions of the preview switch and the reset switch.

[Brief explanation of the drawing]

1 and 2 are side views taken along arrow I in FIG. 6, showing an embodiment of the depth confirmation device for a single-lens reflex camera, and show mutually different operating states. 3 and 4 are front views showing examples of the diaphragm control mechanism 60 in different operating states;
The figure is an operation time chart of the depth confirmation device of the present invention, No. 6
The figure is a front view showing the relationship between the mirror box, the mirror box drive mechanism, and the drive motor. 11...Mirror box, 12...Motor, 13.
... Camera body, 14... Main plate, 16... Output shaft, 20... Mirror box mechanism, 21... Auxiliary main plate, 22... Binion, 23.24... Double gear (
gear train), 25... idle gear (gear train), 26.
...Mirror cam gear (gear train), 27...Shutter/squeezing cam gear (gear train), 28...Mirror cam, 3
0...Mirror drive lever, 33...Mirror, 36.
...Shutter cam, 37...Aperture cam, 39...Shutter set lever-543...Aperture drive lever, 46...
- Aperture linking plate, 47... Interlocking bin, 48... Toshimin spring, 52... Aperture drive protrusion, 53... Aperture bottle, 60... Aperture control mechanism, 63... Sector gear, 6
4... Interlocking roller, 67... Pulse generator, 68...
...Slit disk, 69...Transparent slit, 70...
・Photo interrupter, 71...Lock mechanism, 72...
- Claw member, 74... Locking magnet, 76... Return lever, 80... Rotation angle detection switch, 81... Brush, 82... Land plate, 83... Motor control circuit, 84 ...Preview switch, 85...Preview reset switch. Patent Applicant: Asahi Optical Industry Co., Ltd. Agent: Kunio Miura Figure 6 Procedural Report (spontaneous) 1. Indication of the incident 1988 Patent Application No. 229258 2 Name of the invention Depth confirmation device for single-lens reflex camera Representative Toru Matsumoto Drawing Figure 3

Claims (3)

[Claims] (1) The mirror box is provided with a mirror cam gear and a shutter/diaphragm cam gear that are each driven one rotation from a rest position by the forward rotation of a motor when the shutter is released;
The rotation of the shutter/diaphragm cam gear narrows down the aperture to a predetermined value, and then the shutter can be operated.Then, the rotation of the mirror cam gear retracts the mirror from the optical path, and the shutter is then operated. In a single-lens reflex camera that returns a rear mirror, rotation angle detection means detects a preview rotation position in which the diaphragm is operated but the shutter and mirror are not operated after the mirror cam gear and the shutter/diaphragm cam gear start rotating from an initial rest position. and; a preview switch separate from the release switch that issues a forward rotation signal to the motor; the forward rotation signal from this preview switch causes the motor to start rotating in the forward direction, and when the rotation angle detection means detects the preview rotation position; A motor control circuit that stops the motor; and a preview reset switch that issues a reverse rotation signal to the motor after the motor is stopped; the motor control circuit further reverses the motor in response to a reverse rotation signal from the preview reset switch, and outputs a reverse rotation signal to the mirror cam gear. and a depth confirmation device for a single-lens reflex camera, characterized in that a motor is stopped when a shutter/aperture cam gear returns to an initial rest position. (2) The depth confirmation device for a single-lens reflex camera according to claim 1, wherein the stop signal after the motor is reversed is provided by the rotation angle detection means. (3) The depth confirmation device for a single-lens reflex camera according to claim 1, wherein the preview switch and the preview reset switch are configured by different switch states of a single switch.