JPH06308570A - Motor-driven lens shutter for camera - Google Patents

Abstract

PURPOSE:To prevent power from being consumed unnecessarily and also to prevent a motor from burning by generated heat, etc., by impressing a high voltage on a motor for driving a shutter blade from a driving control circuit in a high speed area and impressing a voltage lower than that in the high speed area on the motor in a low speed area. CONSTITUTION:The lens shutter is provided with an opening motor M1 which is linked with opening shutter blades 2 and 3, a closing motor M2 which is linked with closing shutter blades 4 and 5 and a driving control circuit for dividing an exposure time control area into plural areas and impressing a different voltages, or a different currents on the respective areas. In a high-speed exposure time area, the high voltages, or currents are impressed on the opening motor M1 and the closing motor M2 from the driving control circuit, and then, the opening shutter blades 2 and 3 and the closing shutter blades 4 and 5 are actuated fast, meanwhile, in the case of a low speed exposure time area, the low voltage, or currents are impressed, so that the opening shutter blades 2 and 3 and the closing shutter blades 4 and 5 are actuated slowly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor-driven lens shutter for a camera in which an opening shutter blade and a closing shutter blade are driven by respective motors.

[0002]

2. Description of the Related Art Normally, opening and closing operations of shutter blades are performed by the force of springs. However, as electronic control of cameras has advanced in recent years, more or more operations are performed by motors. Particularly in a large shutter, the shape and mass of the shutter blades are large and it is difficult to achieve high speed, but this can be achieved by adopting this motor drive type. However, if such a system is adopted, the downsizing of the motor and the reduction of the power consumption will be another serious problem. Therefore, in order to reduce the load on the motor as much as possible and improve the exposure characteristics at high speed, the shutter blade for opening and the shutter blade for closing are separately provided, and each shutter is driven by a different motor. Proposed by applicant.

[0003]

In order to increase the speed of a motor-driven lens shutter, it is conceivable to increase the amount of electric power supplied to the motor in addition to reducing the load as described above. To be However, this means that the power consumption becomes large in the case of the low speed (long) exposure time as well as in the case of the high speed (short) exposure time,
In some cases, the motor may generate heat and cause a seizure.

The present invention has been made in view of the above problems, and an object of the present invention is to separately provide an opening shutter blade and a closing shutter blade, and drive them by different motors. It is an object of the present invention to provide a motor-driven lens shutter for a camera, in which the power consumption of the power supply is small even though a high-speed exposure time can be obtained.

[0005]

A motor-driven lens shutter according to the present invention includes an opening motor that operates in conjunction with an opening shutter blade, a closing motor that operates in conjunction with a closing shutter blade, and exposure time control. A drive control circuit that divides the region into a plurality of regions and applies different voltages or currents to the respective regions, and the applied voltage value or current value is smaller in the low-speed exposure time control side region than in the high-speed exposure time control side region. To do so.

[0006]

In the high-speed exposure time region, the applied voltage (current) from the drive control circuit to the motor is high, and the shutter blades operate quickly, but in the low-speed exposure time region, the applied voltage (current) is low. The operation of the shutter blades is slower than in the above case.

[0007]

Embodiments of the present invention will be described with reference to FIGS. 1 is a plan view of a shutter before the start of exposure, FIG. 2 is a plan view of the shutter after the end of exposure, FIG. 3 is an enlarged view of a rotor of an opening motor, and FIG. 4 is a circuit diagram showing an example of a motor drive circuit. is there. 5A and 5B are timing charts of shutter operation. FIG. 5A shows a case in the high-speed exposure time region, and FIG. 5B shows a case in the low-speed exposure time region.

1 to 3, reference numeral 1 denotes a shutter base plate.
And has an exposure opening 1a and slots 1b, 1c
At the same time, pins 1d, 1e, 1f and 1g are planted.
2 and 3 are opening shank pivotally attached to pins 1d and 1e, respectively.
4 and 5 are pivotally attached to pins 1f and 1g, respectively.
It is a shutter blade for closing. M₁Is the shutter base plate 1
It is a motor for opening, which is mounted on the back and is capable of forward and reverse rotation.
This opening motor M ₁The rotor 6 of is clearly shown in FIG.
It is a permanent magnet and is formed integrally with this rotor 6.
The pin 6a on the opened lever is the slot 1 of the shutter base plate 1.
Shutter blade for opening protruding from b to the surface of FIG.
It is fitted in a slot (not shown) provided in the.
In FIG. 3, reference numeral A indicates a magnetic pole which is a magnetic pole.
Yes, when the opening shutter blades 2, 3 are in the closed position,
That is, when the pin 6a is in the solid line position,
A shutter for opening that gives a force in the direction and vibrates or bounces.
The blades 2 and 3 move inadvertently and leak light from the exposure opening 1a.
I try not to do anything. M₂Is the shutter base plate 1
It is a closing motor mounted on the back that can be rotated in the forward and reverse directions.
It has a rotor 7 and a pin 7a.
Opening motor M₁The description is omitted because it is exactly the same as.
These motors M₁, M₂Is a moving magnet
Type motor, but in the camera industry
Known as irismo because it is used to open and close the wings
It is called data.

FIG. 4 shows an example of the drive control circuit according to the present invention. This circuit is a capacitor drive circuit, and by using a capacitor that charges the electromotive force of the battery, the voltage (current) applied to the motor can be set large, and is a circuit suitable for high-speed operation of the shutter blades. In this figure, R ₁ and R ₂ are resistors, and TR ₁ and TR are
₂ is a transistor for power saving.

Next, the operation of the above embodiment will be described with reference to the timing chart shown in FIG. First, in the case of photographing with the exposure time in the high speed region, a signal is output from the controller in FIG. 4 and the power save transistors TR ₁ and TR ₂ are turned on. Then, when the shutter is released, a forward current flows through the coil of the opening motor M _{1 in} the first embodiment, and the rotor 6 rotates counterclockwise. At this time, the opening shutter blade 2 rapidly rotates clockwise around the pin 1d and the opening shutter blade 3 rapidly rotates counterclockwise around the pin 1e by the pin slot connection with the pin 6a. When the opening shutter blades 2 and 3 are completely retracted from the exposure opening 1a, the pin 6a integral with the rotor 6 of the opening motor M ₁ reaches from the solid line position to the broken line position in FIG. Motor M for opening during this opening operation
_{Since the} voltage applied to ₁ is extremely high (for example, 5 V), as shown in FIG.
It takes a very short time for 3 to reach from the pinhole position to the fully open position. After that, the opening motor M ₁ is energized until the photographing is completed.

After the opening motor M ₁ is energized, the closing motor M ₂ is energized. The time when the closing motor M ₂ is energized may be before the opening shutter blades 2 and 3 reach the fully open position, as can be seen from FIG. 5A. When the closing motor M ₂ is energized, the rotor 7 rotates clockwise, and the closing shutter blade 4 rotates clockwise around the pin 1f and the closing shutter blade 4 due to the pin slot connection with the pin 7a. 5 rotates counterclockwise around the pin 1g. The closing shutter blades 4 and 5 are the exposure opening 1
When a is completely covered, one shot is completed and each shutter blade is in the state shown in FIG.

The shutter is charged by applying a current to the motors M ₁ and M ₂ in the opposite direction to that described above. First, after the opening shutter blades 2 and 3 reach the state shown in FIG. , The closing shutter blades 4 and 5 are operated and stopped in the state of FIG. In order to enhance the light blocking effect of the exposure opening 1a, the closing shutter blades 4 and 5 are placed in a state of covering the exposure opening 1a in the same manner as the opening shutter blades 2 and 3 in the charged state of the shutter, and at the time of shutter release. First, the closing shutter blades 4 and 5 may be returned to the positions shown in FIG. 1 and then the opening shutter blades 2 and 3 may be opened, which is particularly effective in the case of a large shutter.

Next, in the case of photographing with the exposure time in the low speed region, the power save transistor TR ₁ ,
TR ₂ is off. In this case, the opening motor M
_The voltage applied to ₁ is lower than that in the above case (for example, 3 V) by the action of the resistors R ₁ and R ₂ . Therefore, as shown in FIG. 5B, it takes a long time for the opening shutter blades 2 and 3 to reach the fully open position from the pinhole. After that, when the closing motor M ₂ is energized after a predetermined time elapses, the closing shutter blades 4 and 5 operate to close the exposure opening 1a. In the above embodiment, the exposure time control region is divided into two stages, a high speed region and a low speed region, but it may be divided into three or more stages.

[0014]

As described above, according to the present invention, the exposure time control area is divided into two or more stages, and in the high speed area, a large voltage (current) is applied from the drive control circuit to the motor for driving the shutter blades. By applying a smaller voltage (current) in the low-speed area than in the high-speed area, it is not necessary to continue applying a large voltage (current) in the low-speed area for a long time, and unnecessary power consumption is increased. It is possible to prevent the burn-in of the motor due to heat generation.

[Brief description of drawings]

FIG. 1 is a plan view showing a state before starting exposure of a lens shutter which is an embodiment of the present invention.

FIG. 2 is a plan view similar to FIG. 1 showing a state after completion of exposure.

3 is an enlarged view of the motor rotor shown in FIGS. 1 and 2. FIG.

4 is a circuit diagram showing an example of a drive control circuit of the motor shown in FIGS. 1 and 2. FIG.

5A and 5B are time charts showing the relationship between the operation of the shutter and the voltage applied to the motor. FIG. 5A shows the case of a high-speed exposure time, and FIG. 5B shows the case of a low-speed exposure time.

[Explanation of symbols]

1 Shutter base plate 1a Exposure opening 1b, 1c Slots 1d, 1e, 1f, 1g, 6a, 7a Pins 2, 3 Opening shutter blades 4, 5 Closing shutter blades 6, 7 Rotor M ₁ Opening motor M ₂ Closing Motor R ₁ , R ₂ resistance TR ₁ , TR ₂ power save transistor

Front Page Continuation (72) Inventor Shigeru Takahashi 16-20 20 Shimura, Itabashi-ku, Tokyo Copal Co., Ltd. (72) Inventor Yoshiyuki Ozeki 16-20 20 Shimura, Itabashi-ku, Tokyo Copal Co., Ltd. (72 ) Inventor Koichi Kobayashi, 16-20, Copal Co., Ltd., 2 Shimura, Itabashi-ku, Tokyo (72) Inventor Kenji Nakagawa 2 16-20 Copal, Ltd., Shimura, Itabashi-ku, Tokyo (72) Inventor Tomio Kurosu Tokyo 16-20 Copal Co., Ltd. 2-2 Shimura, Itabashi-ku, Tokyo (72) Inventor Toyonori Sasaki 20-20 Copal Co., Ltd. Shimura, Itabashi-ku, Tokyo

Claims (4)

[Claims] 1. An opening motor interlocking with an opening shutter blade, a closing motor interlocking with a closing shutter blade, an exposure time control region is divided into a plurality of regions, and different voltages are applied to the respective regions. Or a drive control circuit for applying a current to each of the motors, wherein the applied voltage value or current value is smaller in the low speed exposure time control side region than in the high speed exposure time control side region. Motor driven lens shutter for cameras. 2. The motor-driven lens shutter for a camera according to claim 1, wherein the plurality of areas are a high-speed exposure time control area and a low-speed exposure time control area. 3. The shutter blade for opening and the shutter blade for closing are each composed of two blades that operate in directions substantially opposite to the optical axis.
Alternatively, the motor-driven lens shutter for a camera according to the item 2. 4. The motor-driven lens shutter for a camera according to claim 1, wherein the opening motor and the closing motor are arranged symmetrically with respect to the optical axis. .