JPH057693B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a shutter for a camera, and more particularly relates to activation of an exposure time setting circuit for determining exposure and stopping of a motor for charging and releasing the shutter. The present invention relates to a camera shutter that allows the camera to be shuttered.

(Prior Art) A so-called motor-driven camera in which the shutter is charged by a motor is usually configured to charge the shutter by the motor and then release the shutter by a separate release button or the like.

By the way, this type of camera is naturally equipped with a switch to start the motor.
If the switch for starting the motor is not set back to OFF after the exposure is completed, the camera will release the camera as it is, and as a result, if the release button is pressed after a long exposure, the shutter will no longer operate. arise.

Of course, to solve this kind of problem, it would be possible to install a separate motor stop switch to disable the release operation, but this requires a separate circuit means, which is disadvantageous in terms of cost. In addition to causing problems such as significantly impairing operability, reliability, etc.

(Purpose) The present invention has been made in view of the above circumstances, and its purpose is to use the same member to start an exposure time setting circuit that determines exposure and to stop the shutter member charging motor. Therefore, an object of the present invention is to provide an automated camera shutter that does not cause malfunctions.

Another object of the present invention is that, in adopting the above-mentioned means, it is possible to reduce the influence of so-called motor noise, which occurs when cutting off the motor load current, on the charging characteristics of the time-limiting capacitor. It is an object of the present invention to provide a shutter for a camera, which can remove brightness and obtain appropriate exposure according to the brightness of a subject.

(Structure) Therefore, details of the present invention will be described below based on illustrated embodiments.

FIG. 1 shows a program shutter mechanism constituting an embodiment of the present invention, and first, an overview of its structure and operation will be explained.

This program shutter consists of a drive lever 1 which is rotatably biased to the charge position by a cam 2 driven by a motor 3, and then performs a release operation for exposure operation, and a blade release lever on the drive lever 1. a blade lever 5 that engages and disengages from the shutter blade 4, and operates so as to open the shutter blades 6, 6 by being biased by the drive lever 1 when engaged, and to close the shutter blades 6, 6 by its own biasing force when disengaging; After the exposure time has elapsed, the iron piece lever 7 reverses as the electromagnet 8 is deenergized and acts on the blade release lever 4 to release the blade lever 5, and an exposure time setting circuit that determines exposure according to the brightness of the subject. , a timing switch 9 that stops the power supply to the motor 3 and starts the exposure time setting circuit, and a sector wheel 10 that opens the timing switch 9 in conjunction with the blade opening operation of the blade lever 5.
and a governor mechanism 11 that controls the speed of the blade lever 5 via this sector wheel.

In the program shutter configured in this way, when the power switch is first turned on, the cam 2 driven by the motor 3 rotates clockwise in the figure.
The drive lever 1 is rotated to the left by pressing the arm 1a that has entered the rotation locus. Therefore, the other arm 1b of the drive lever 1 presses the iron piece lever 7 to cause it to be attracted and held by the electromagnet 8, while moving the tip of the blade release lever 4 to the engagement position with the blade lever 5. The state shown in the figure is reached.

When the cam 2 further rotates from this state, the disengaged drive lever 1 rotates clockwise in the figure due to its own biasing force, opening the blade release lever 4 pivoted on the other arm 1b. While pushing up the blade lever 5 and rotating it to the left at a speed controlled by the governor mechanism 11, the two shutter blades 6, 6 are rotated via the pin 5a to open the optical path.

On the other hand, the fan wheel 10, which has started to rotate clockwise in the figure along with the counterclockwise rotation of the blade lever 5, has its pin 1
Lead piece 9 of timing switch 9 by 0a
A is pressed to open the circuit, and with this point in time as a reference, there is a time difference between stopping the power supply to the motor 3 and starting the exposure time setting circuit.

When the exposure time corresponding to the subject brightness has elapsed, the charge in the capacitor of the exposure time setting circuit described above reaches a predetermined level, and the electromagnet 8 is accordingly deenergized. As a result, the iron piece lever 7 begins to rotate clockwise in the drawing due to its own biasing force, and its rear pin 7a presses the lower part of the blade release lever 4 to rotate it to the right. Unlock. Therefore, the blade lever 5 is again regulated by the governor mechanism 11 and rotates to the right due to its own biasing force, and the pin 5
The two shutter blades 6, 6 are closed via a.

On the other hand, the sector wheel 10 rotates counterclockwise in the figure following the blade lever 5, releases the pressure on the reed piece 9a, and returns the timing switch 9 to the ON state.

Therefore, the shutter control device of the present invention will be explained below.

FIG. 4 shows an embodiment of the control device, in which reference numeral 40 is a signal processing section constructed using integrated circuit technology, which is operated from a battery 21 via a power switch 20 provided on the camera body. When voltage is supplied, each input terminal has a timing switch 9 and an N/N switch for switching between normal operation and self-timer operation.
S selection switch 22, Cds for detecting subject brightness
A light receiving element 23, a time setting capacitor 24, variable resistors 25a to 25f for adjusting exposure, and a resistor 26a and a capacitor 26b forming an oscillation circuit are connected to the output terminal for driving a shutter charge motor 3.
A switching transistor 27 for stopping, a switching transistor 29 for short-circuiting the armature of the motor 3 through a brake resistor 28, a light emitting display element 30 for indicating self-timer operation, a strobe switch 33, etc. are connected as external components, and a timing signal is generated. , an electromagnet drive signal, a motor drive-stop signal, an exposure signal, and the like.

Next, this signal processing section will be explained in more detail.

Reference numeral 41 in the figure is a timer circuit that sets the time difference between stopping the motor 3 and starting the exposure time setting circuit 54 and generates time signals for various limiters. It selects and outputs a predetermined time signal such as 10 seconds, 7 seconds, 40 milliseconds, 16 milliseconds, 6 milliseconds, 3 milliseconds, 1.75 milliseconds, etc.

44 is an all-clear circuit that checks the voltage level of the battery 21 using the first clock from the oscillator 42, and when a predetermined voltage is reached, the processing unit 40
It outputs an initial setting signal that initializes the entire logic.

Reference numeral 45 denotes a normal/self determination circuit that determines whether it is normal operation or self-timer operation, and determines whether it is normal mode or self-mode depending on whether the N/S selection switch 22 is OFF or ON. 48 and electromagnetic latch circuit 49 to set these circuits 48 and 49. In the self-mode, the self-time display element 30 is lit based on the signal from the timer circuit 41, and after the lighting is finished, the motor latch is turned on. This is used to set the circuit 48 and the electromagnetic latch circuit 49.

46 is a timing detection circuit that detects the signal from the timing switch 9, and includes a first transistor 46a whose base electrode is connected to the normally closed contact of the timing switch 9, and which is turned off when the contact 9a of the switch is opened; A second transistor 46b which sets the timing signal latch circuit 47 by setting the timing signal latch circuit 47, a third transistor 46c which is turned ON by setting this circuit 47, and this transistor 46c supplies the power supply voltage Vcc to the base electrode of the first transistor 46a. and a fourth transistor 46b which cuts off the first transistor 46a, and is configured to reliably hold the operation of the timing switch 9.

Reference numeral 48 designates the aforementioned motor latch circuit, into which signals from the all clear circuit 44, the N/S determination circuit 45, the timing signal latch circuit 47, and the AND circuit consisting of the NOR gate G1 and the inverter I1 are input, and the all clear circuit operates in the normal mode. 44
The motor drive transistor 27 is turned on and the brake transistor 29 is turned on by the signal from
The motor drive transistor 27 is turned OFF and reset by the logical product of the inverted signal from the timing signal latch circuit 47 and the signal from the terminal T1 of the timer circuit 41 that is generated after a predetermined period of time, for example, 16 milliseconds have elapsed since the generation of this signal. OFF, the brake transistor 29 is turned ON, and when the self-mode is set, when the self-time signal from the N/S judgment circuit 45 ends, it is set, the motor drive transistor 27 is turned ON, and the brake transistor 29 is turned ON.
9 is OFF, timing signal latch circuit 47
The inverted signal from and the predetermined time from the generation of this signal
For example, timer circuit 41 that occurs after 16 milliseconds have elapsed.
It is reset by logical AND with the signal from the terminal T1.

Reference numeral 49 denotes an electromagnet latch circuit, into which signals from the N/S determination circuit 45, timing signal latch circuit 47, and electromagnet deenergization timing circuit 55 (described later) are input, and in the normal mode, it is set by an initial setting signal to excite the electromagnet 8. Then, the electromagnet 8 is reset by a signal from the electromagnet deenergization timing circuit 55.
In the self mode, it is set when the self-time signal from the N/S determination circuit 45 ends, and is reset by a signal from the electromagnetic deenergization timing circuit 55.

Reference numeral 50 denotes a current circuit, into which the brightness signal of the subject detected by the light receiving element 23, the variable resistor for level setting during strobe photography, the variable resistor for level setting during AE photography, and a signal based on the set level are input, It outputs a constant current that is proportional to the brightness or the exposure amount for flash photography, regardless of the load impedance.

Reference numeral 54 denotes an exposure time setting circuit, which includes a transistor 54a which is turned off by resetting the timing signal latch circuit 47 and enables the time setting capacitor 24 to be charged with the current from the current circuit 50; and one input terminal connected to the capacitor 24. , a comparator 54c whose other input terminal is connected to a resistor 54b that sets a reference level, and is configured to invert the comparator 54c when the terminal voltage of the timing capacitor 24 reaches the reference level.

55 is the aforementioned electromagnet deenergization timing circuit;
When any of the longest exposure limit signal during AE photography, the strobe photography time limit signal, and the inverted signal from the exposure time setting circuit 54 is input, it is inverted and outputs a reset signal.

56 is a reset pulse generation circuit, which outputs a reset pulse to the oscillator 42 and frequency divider 43 when the timing signal latch circuit 47 is inverted, and resets these circuits 42 and 43 to generate a reset pulse when the timing switch 9 is turned off and when the motor 3 is turned off. Initial settings are made for time signals such as the time difference from when the power supply is stopped and the limiter time, and the electromagnet deenergization timing circuit 47
The oscillator 42 and frequency divider 43 are reset by the inversion of .

57 is an AE that identifies strobe photography and AE photography.
The determination circuit detects that when the strobe switch 33 is OFF, the transistor 58 is also OFF, determines that AE photography is being performed, and activates the AE latch circuit 59.
to cut off the transistor 60,
When the switch 33 is ON, it is determined that flash photography is being performed, and the AE latch circuit 59 is reset.
This makes the transistor 60 conductive. In addition,
Reference numerals 61 and 62 in the figure respectively connect the strobe terminal and the exposure operation end signal terminal to the motor latch circuit 48.
64 is a motor noise absorbing capacitor, 65 is an electromagnetic paracapacitor, and 66 is a power supply capacitor.

Next, the operation of the control device configured as described above will be explained based on the timing diagrams shown in FIGS. 3 and 4.

Shooting in normal mode N/S selection switch 2 provided on the camera body
When the power switch 20 is turned on while normal photography is selected by operating the oscillator 2, the oscillator 42 operates, and if the power supply voltage level is normal, a signal is output from the all clear circuit 44. As a result, the motor latch circuit 48 and the electromagnet latch circuit 4
9 are set respectively, and the motor 3 is driven and the electromagnet 8 is excited. As the motor 3 rotates, the iron piece lever 7 rotates toward the electromagnet 8 and is attracted and held by the electromagnet 8. When the motor 3 further rotates from this state, the blade lever 5 is pushed up and the two shutter blades 6 are rotated to open the optical path.

On the other hand, as the vane lever 5 rotates, the pin 11a of the sector wheel 11 presses the lead piece 9a of the timing switch 9, opening it. Opening this switch 9 inverts the timing signal latch circuit 47. This resets the motor latch circuit 48, turns off the transistor 54a of the exposure time setting circuit 54, and starts charging the time setting capacitor 24 with a current proportional to the subject brightness while the motor 3 is rotating. At the same time, due to the inversion of the timing signal latch circuit 47, the reset pulse generation circuit 56 is activated, and the timer circuit 41 starts counting time. When 16 milliseconds have elapsed after the start of time measurement,
Since a signal is output from terminal T5 of the timer circuit 41, a signal is output from the AND circuit (G1, I1), cutting off the power supply to the motor 3, and turning on the brake transistor 29 to apply regenerative braking to the motor 3. Stop the motor 3 quickly. When a time proportional to the subject brightness has elapsed, the terminal voltage of the time setting capacitor 24 reaches a set level, the comparator 54 is inverted, and the electromagnet deenergization timing circuit 55 is inverted. As a result, the electromagnetic latch circuit 4
9 resets the power supply to the electromagnet 8, releases the iron lever 7, closes the shutter blades 10, and performs exposure proportional to the brightness of the subject. When 16 milliseconds have elapsed since the reversal of the electromagnet deenergization timing circuit 55, the signal from the timer circuit 41
At _T2 , an exposure operation end signal OE is output, and, for example, a film winding motor (not shown) is activated to wind the film by one frame. At the same time, the reset pulse generation circuit 56 is activated by the electromagnet deenergization timing circuit 5.
5, the oscillator 42 and frequency divider 43 are reset, and the limiter time measurement is started.

In this way, the sector wheel 10 continues to rotate even after the exposure is completed, and the timing switch 1
2 returns to the ON state. In this state, the camera waits for the next release. When the camera is released next time, the timing signal latch circuit 47 is reset by the output of the all clear circuit 44, the transistors 46c and 46d are turned off, and the timing switch 12 is turned off.

Shooting in self-timer mode When the power switch 20 is turned on with self-timer shooting selected by the N/S selection switch 22, the N/S determination circuit 45 detects that it is the self-time shooting mode, and the motor latch circuit 4
8 and the electromagnetic latch circuit 49 are prevented from being activated by the signal from the all-clear circuit 44, and the light-emitting display element 30 is turned on and off for 7 seconds and then continuously turned on for 3 seconds. When the predetermined self-time has elapsed in this way, the motor latch circuit 4
8 and the electromagnetic latch circuit 49, and then the exposure is completed through the same process as in normal mode photography described above (FIG. 4).

FIG. 5 shows a second embodiment of the present invention, in which a timing signal latch circuit 47 and a timer circuit 4 are connected to the base electrode of a transistor 54a forming an exposure time setting circuit 54 via a NAND gate G2.
According to this embodiment, as shown in FIG. 6, 3 milliseconds have elapsed since the power supply to the motor 3 was stopped. When the supply voltage from the power supply becomes constant, charging of the time setting capacitor 24 is started, and the exposure time is set while avoiding the influence of noise caused by cutting off the current to the motor 3.

FIG. 7 shows a third embodiment of the present invention, in which the brake transistor 29 is not operated directly by the output of the motor latch circuit 48, and the output signal of the motor latch circuit 48 and the inverted signal of the timing signal latch circuit 47 are used. , and a 16 millisecond signal from the terminal T7 of the timer circuit 41 are input to a three-terminal AND circuit consisting of a NOR gate G3 and an inverter I3, and the transistor 29 is operated by the logical product of these three signals. According to this embodiment, as shown in FIG. 8, regenerative braking of the motor 3 is performed 16 milliseconds after the start of charging of the time setting capacitor 24, and the noise generated during braking is affected by the exposure time setting. influence can be prevented.

FIG. 9 shows a fourth embodiment of the present invention, in which the brake transistor 29 is not operated directly by the output of the motor latch circuit 48, and the output signal of the motor latch circuit 48 and the inverted signal of the timing signal latch circuit 47 are used. , and a 3 millisecond signal at terminal T8 from timer circuit 41 are input to a three-terminal AND circuit consisting of NOR gate G3 and inverter I3, and the brake transistor 29 is operated by the logical product of these three signals, and at the same time The timing signal latch circuit 47 and the terminal T8 of the timer circuit 41 are connected to the base electrode of the transistor 54a forming the time setting circuit 54 via the NAND gate G2.
As shown in Fig. 10, the power supply to the motor 3 is cut off immediately after the timing switch 12 is turned off and the timing signal latch circuit 47 is reversed. Charging is started when 3 milliseconds have elapsed since the power supply was stopped, and regenerative braking is applied at the same time, so that a stable charging current can be supplied to the time-limiting capacitor 24 and the motor 3 can be stopped quickly. .

FIG. 11 shows a fifth embodiment of the present invention, in which a 3 millisecond time signal is supplied to the NAND gate G2 and a 6 millisecond time signal is supplied to the NAND gate G3 in the embodiment of FIG. As shown in Fig. 12, the power supply to the motor 3 is stopped → the time setting capacitor 24
By performing control in the order of charging start → regenerative braking of the motor 3, more stable charging of the capacitor 24 and rapid stopping of the motor 3 are achieved.

Next, the adjustment of exposure time corresponding to the brightness of the subject will be explained.

The operational amplifier 51 operates during automatic exposure shooting (AE).
When the transistor 60 is turned off, the load voltage determined by the sum of the level setting variable resistor 25d during strobe photography and the level setting variable resistor 25e during AE photography is turned on, and when the transistor 60 is turned on during strobe photography (FM). Since the load voltage determined by the level setting variable resistor 25d during strobe photography is applied, the input terminal connected to the other input terminal
A current proportional to the load voltage flows through the Cds light receiving element 23, and the diode 52a and transistor 5
A logarithmically compressed voltage Vcds is generated by a logarithmically compressed circuit 52 consisting of 2b. On the other hand, the current flowing through the inflection point adjusting variable resistor 25a generates a voltage Vw logarithmically compressed by the logarithm compression circuit 63.
These two voltages Vcds and Vw are divided by the high brightness correction variable resistor 25b and the low brightness correction variable resistor 25c, respectively, and input to the gamma correction circuit 53. If the voltage Vcds is larger than the voltage Vw, the gamma correction circuit 53 sets the voltage determined by the high-brightness side correction variable resistor 25b, and if the voltage Vcds is smaller than the voltage Vw, the gamma correction circuit 53 controls the voltage determined by the low-brightness side correction variable resistor 2.
5c and select the voltage determined by the current circuit 5.
The current circuit 50 expands this input voltage to generate a current and outputs it to the time setting capacitor 24 to create an accurate exposure time proportional to the subject brightness. Note that this current circuit 50
A current determined by the variable resistor 25f for the high brightness limiter is input to the
3, and the smaller current is selected as the charging current for the time-fixing capacitor 24.

Since the exposure amount is adjusted using this circuit configuration, 1. Variable resistor 25 for level setting during strobe photography
d or by adjusting the level setting variable resistor 25e during AE shooting, the Cds light receiving element 23
By adjusting the voltage applied to the
Alternatively, the exposure can be automatically switched at a fixed ratio during AE shooting, and 2. By adjusting the inflection point setting variable resistor 25a, the inflection points on the high brightness side and the low brightness side can be set. Furthermore, the maximum current from the current circuit 50 is regulated by the high brightness limiter variable resistor 25f,
By ensuring the shortest exposure time, it is possible to minimize photographic errors.

(Effects) As described above, according to the present invention, output means for outputting a stop signal and a start signal are provided to the motor that charges and releases the shutter, and to the circuit means that determines exposure according to subject brightness, respectively. Since this is operated by an actuating means that is linked to the opening/closing means of the shutter, a series of exposure operations of the shutter can be performed in an ever-set manner, making the operation extremely simple. It is possible to prevent malfunction of the shutter and reduce manufacturing costs by disabling the shutter release after exposure is completed without requiring a member such as a switch that complicates the shutter mechanism. In addition, the circuit means that determines the exposure according to the brightness of the subject is activated before or after the power supply to the shutter charge motor is stopped, regardless of the noise that occurs when the load current is cut off. The exposure amount can always be determined according to the subject brightness,
Reliability can be improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a program shutter mechanism which is an embodiment of the present invention, and FIG. 2 is a block diagram of a device which is a first embodiment of a control device for controlling the shutter mechanism. 3 and 4 are timing diagrams showing the operation of the above device, respectively.
Figures 7, 9, and 11 are block diagrams showing other embodiments of the control device according to the present invention, and Figures 6, 8, and 1 are block diagrams, respectively.
0 and 12 are timing diagrams showing the operation of the above device, respectively. 3...Motor, 1...Drive lever (drive member),
4... Blade release lever, 7... Iron piece lever, 5...
...Blade lever (opening/closing member), 9...Timing switch (output means), 40...Control circuit, 41...
...Timer.

Claims (1)

[Claims] 1. A motor 3 that rotates in one direction to charge the shutter drive member 1 and release the member, a circuit means 40 that determines exposure according to the brightness of the subject, and a circuit means 40 for determining the exposure according to the brightness of the subject; Output means 9 for outputting a stop signal and a starting signal for the circuit means, engaged with the drive member 5 at the time of charging, and releasing the shutter blade by subsequent release operation, and releasing the engagement. The shutter opening/closing member 5 is configured to close the shutter blade by the shutter blade, the electromagnet 8 terminates the exposure by releasing the engagement based on the output of the circuit means, and Actuation means 10 for actuating the output means, and means 41 for generating a time difference between the stop signal from the output means and the activation signal.
A shutter for the camera.