JPH0626893Y2 - Shutter device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a shutter device for a camera.

[Problems to be solved by conventional techniques and devices]

In the case of an auto-focus type camera, at the time of shutter release, first the distance is measured and the lens is moved by an amount corresponding to the measured distance to achieve focusing, and then the shutter blades are opened to obtain an appropriate exposure amount. After it is obtained, it will be closed. Then, there is a system in which the lens movement is controlled by pulse-driving a lens position changing member such as a cam or helicoid using an actuator such as a stepping motor. This is because (1) a lens movement position sensor is unnecessary. As the control method (2), the initial (actuation start) position of the lens is always constant, and the subsequent lens movement is performed according to the number of pulses input from the circuit, and the momentary lens position feedback is not performed. , So-called open control is possible, which simplifies the circuit,
(3) Although it had the advantage of simplifying the mechanical mechanism, etc., on the other hand, since it is open control, even if the lens position shift occurs, it cannot be detected and corrected. In order to prevent this, it is necessary to take in fixed position information signals such as a lens start position signal and an intermediate position signal as input information at the start of operation.

However, if the means for generating the lens fixed position information signal and the shutter open position signal are separately provided for that purpose, there is a problem that the number of parts increases and the structure becomes complicated.

The present invention has been made in view of the above problems, and an object thereof is to provide a shutter device capable of obtaining a fixed position information signal required for accurate lens movement without complicating the structure.

[Means and Actions for Solving Problems]

The shutter device according to the present invention is a shutter device including a lens driving mechanism and a shutter control mechanism, in which a part of the shutter blades shields the light guided to the optical sensor to generate a signal. When the lens drive ring of the lens drive mechanism is in a predetermined position, the shutter blade is interlocked and the signal becomes a lens fixed position information signal, and otherwise the signal becomes a shutter open position signal. As a result, the means for generating the fixed position information signal and the shutter opening position signal need not be provided separately.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the illustrated embodiment.

FIG. 1 is a plan view of the shutter device of the present invention when it is closed (at the time of shooting), and FIG. 2 is a plan view when it is open (at the time of shooting).

1 has an exposure opening 1a and a support shaft 1b at a predetermined position,
A substrate 3 provided with an optical sensor 2 connected to 1c and an exposure control circuit is pivotally attached to a support shaft 1b, and a tip thereof has a predetermined arc on the support shaft 1b as a center and on the optical sensor 2. A plurality of, for example, 6 through holes 3 at a pitch of
The first shutter blades 4 provided with a ₁ , 3a ₂ , ..., 3a ₆ are pivotally attached to the same support shaft 1b, and the tip thereof is centered on the support shaft 1b and on the optical sensor 2. A plurality of, for example, seven through holes 4a ₁ , at a predetermined pitch on the passing arc.
Second shutter blades 4a ₂ , ..., 4a ₇ are provided,
Reference numeral 5 denotes a back side of the substrate 1, which is pivotally attached to a support shaft 1c and is loosened by a spring (not shown). The tip end and substantially the center part of one arm of the first and second shutters are connected by a pin-slot connection. An opening / closing lever which is connected to each of the blades 3 and 4 and has a hole 5a provided at a position close to the support shaft 1c of the one arm and a pin 5b provided at the tip of the other arm, and 6 is an upper substrate (not shown) The motor 7 is fixed to the motor 6 and reciprocally rotates within a predetermined set angle range and is controlled by an exposure control circuit (not shown). The motor 7 is fixed to the rotor of the motor 6 and is slidably engaged with the hole 5a. These drive pins are included in the shutter control mechanism.
The open / close lever 5 has a spring for left-handed habit (closed habit).
May be added. Further, instead of the pin 5b, the tip of the other arm of the opening / closing lever 5 may be formed as a circular protrusion.

Reference numeral 8 denotes a backside of the substrate 1 which is rotatably mounted concentrically with the exposure opening 1a, and a projection provided on a part thereof has an arc-shaped gear portion 8a and a cam portion 8b capable of contacting the pin 5b. The formed lens drive ring 9 is a drive pinion connected to a drive source such as a stepping motor of an automatic focus detection mechanism (not shown) and meshed with the arcuate gear portion 8a.
These constitute a lens driving mechanism.

When the lens driving ring 8 is at the position shown by the alternate long and short dash line in FIG. 1 (closest photographing position), the cam portion 8b contacts the pin 5b,
Since the opening / closing lever 5 is slightly turned to the right as it is pushed up, the first shutter blade 3 is slightly turned to the right as shown by the alternate long and short dash line, and at this time, the through hole 3a ₁ is moved to the optical sensor 2
It is supposed to overlap.

Next, the operating principle of the proposed shutter device will be described.

When the lens barrier (not shown) is opened in the state shown in FIG. 1, the lens driving ring 8 is rotated rightward as shown by the alternate long and short dash line to interlock with this and the lens is extended to the closest photographing position. At this time, the cam portion 8b is pin 5
Since the opening / closing lever 5 is turned to the right a little by contacting b, the first shutter blade 3 is turned to the right slightly as shown by the one-dot chain line. At this time, the through hole 3a ₁ overlaps the optical sensor 2 and the optical sensor 2 is turned on. Has become. Although only the through hole 3a ₁ has a rectangular shape, this is only adapted to the optical sensor 2 and is not particularly limited to this shape.

Next, when the photographer presses a release button (not shown), distance measurement by the automatic focus detection mechanism and photometry by the exposure control circuit are performed, and then the lens drive ring 8 is rotated counterclockwise by the drive pinion 9 as the drive source (not shown) is operated. The pin 5b is disengaged from the cam portion 8b by the start of left rotation. Then, since the opening / closing lever 5 is returned to the position shown by the dotted line in FIG. 1 and the first shutter blade 3 is returned to the position shown by the solid line in FIG. ₁ , the through hole 3a ₁ is detached from the optical sensor 2 and the optical sensor 2 is turned off. , At this time, the optical sensor 2 is ON
The signal when the signal changes from OFF to OFF is sent to the automatic focus detection mechanism as a lens start position signal (fixed position information signal). Therefore, the automatic focus detection mechanism turns the lens drive ring 8 to the left as shown in FIG. 2 by the drive pinion 9 corresponding to the number of pulses corresponding to the measurement distance, that is, the drive pinion corresponding to the input of this signal, and holds the lens at the focus position. cause.

Next, after a lapse of a predetermined time after the drive pinion 9 is stopped, the motor 6 starts to rotate to the right in FIG. 1 by a signal from the exposure control circuit, which causes the opening / closing lever 5 to rotate to the right via the pin 7. As a result, the first and second shutter blades 3 and 4 are turned to the right and left respectively, and the exposure opening 1a is opened as shown in FIG. Then, first, the through holes 3a ₁ , 3a ₂ , ..., 3a _{6 of} the first shutter blade 3 sequentially pass over the optical sensor 2 to turn the optical sensor 2 on and off, and a pulse signal (at this time) is generated. The exposure control circuit detects the number of shutter open position signals) and the interval (time) between them. Subsequently, after the optical sensor 2 is once in a state where it is not covered by the first shutter blades 3 (the control circuit also detects this as one pulse. Therefore, the through hole 3a of the first shutter blades 3 at this point. ₆ and the through hole 4a ₁ of the second shutter blade 4 must be set appropriately.) This time, the second shutter blade 4 covers and turns on and off, and then the through hole 4a.
a ₁ , 4a ₂ , ..., 4a ₇ sequentially pass over the optical sensor 2 to turn the optical sensor 2 on and off, and the number of pulse signals generated in these cases and their intervals (time)
Etc. are also detected in the exposure control circuit. Then, when the number of pulses is detected such that the product of the previously measured light intensity and the opening amount of the exposure opening 1a coincides with the proper exposure amount, or the proper exposure amount time information after reaching the fully opened state, When it is obtained, the motor 6 rotates in the reverse direction, so that the opening / closing lever 5 immediately turns counterclockwise to the left and right to rotate the first and first shutter blades 3 and 4, respectively, and closes the exposure opening 1a as shown in FIG. .

Note that the ON / OFF relationship for obtaining various signals may be completely opposite to that in the above embodiment. Further, the lens driving ring 8 may be brought to the farthest photographing position when the lens barrier is opened, and the start position signal may be issued when the release button is pressed thereafter.

The operating principle of the proposed shutter device has been described above.
As described above, the shutter device of the present invention is brought into an interlocking state with the first shutter blade 3 via the opening / closing lever 5 when the lens driving ring 8 is at the closest photographing position (or the farthest photographing position).
Since a part of the shutter blade 3 guides or shields the light from the optical sensor 2 to generate the fixed position information signal in addition to the exposure control signal, the fixed position information signal and the shutter open position signal are generated. It is not necessary to separately provide a means for generating Therefore, the fixed position information signal required for accurate lens movement can be obtained without complicating the structure.

[Effect of device]

As described above, the shutter device according to the present invention has an important practical advantage that a fixed position information signal required for accurate lens movement can be obtained without complicating the structure.

[Brief description of drawings]

1 is a plan view of an embodiment of the shutter device according to the present invention when it is closed, and FIG. 2 is a plan view of the above embodiment when it is open. 1 ... Substrate, 1a ... Exposed opening, 1b, 1c ... Spindle,
2 ...... light sensor, 3 ...... first shutter blade, 4 ...... second shutter _{blade, 3a 1, 3a 2, ····} , 3a 6, 4a
₁ , 4a ₂ , ..., 4a ₇ ... through hole, 5 ... opening and closing lever, 5a ... hole, 5b ... pin, 6 ... motor, 7 ...
Drive pin, 8 ... Lens drive ring, 8a ... Arc gear part,
8b ... Cam section, 9 ... Drive pinion.

Claims (1)

[Scope of utility model registration request] 1. A shutter device comprising a lens driving mechanism and a shutter control mechanism, wherein a part of the shutter blades shields light guided to an optical sensor to generate a signal. When the lens driving ring of the lens driving mechanism is at a predetermined position, the lens driving ring is in an interlocking state with the shutter blade and the signal becomes a lens fixed position information signal,
In other cases, the shutter device is characterized in that the above-mentioned signal becomes a shutter open position signal.