JPS6133170B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an electric shutter for a camera, and more particularly to an electric shutter having a power supply voltage determination function. For cameras that use an electric shutter,
Since a dry battery with a relatively small current capacity is used as the power source for driving the electric shutter, in order to use the power source effectively and reduce power consumption as much as possible,
When the camera is not in use, the above power supply to the electric shutter drive circuit is stopped, and only when shooting.
The power is supplied to the electric shutter circuit by pressing the shutter button. Also,
In order for the electric shutter circuit to operate properly,
A power supply voltage determination circuit is provided to check whether the voltage of the power supply is higher than a reference voltage value in relation to the shutter release operation before taking a picture, and only when the voltage is higher than the reference voltage value, the electric shutter circuit is activated. The electric shutter circuit is operated normally by supplying the power to the electric shutter circuit, and when the voltage of the power source drops below the reference voltage value, the power supply to the electric shutter circuit is stopped and the electric shutter circuit is operated normally. I am trying not to activate the electric shutter. Incidentally, in such electric shutters, dry batteries with a relatively low current capacity are used as the power source, but as is well known, these dry batteries are generally susceptible to continuous use and temperature changes.
With continuous use, its output voltage will decrease. However, if you do not use it for a certain period of time,
Its output voltage has the property of recovery. This phenomenon is particularly noticeable when the battery is nearing the end of its life and its voltage is unstable. In other words, if a dry battery is nearing the end of its life and has unstable voltage, if it is not used for a while, its output voltage will recover and the terminal voltage will show a normal value, but when it is used, current will flow, When power is consumed, its output voltage drops immediately, and it is no longer able to supply normal power. If the dry battery power source of the electric shutter is in this state, press the shutter button to connect the dry battery power to the electric shutter circuit, and then immediately connect the battery power to the electric shutter circuit. When the voltage of the dry battery power source is checked by the voltage determination circuit, the voltage of the dry battery is
Since it has recovered, it shows a normal reference voltage value.
Therefore, this drives the electric shutter circuit and operates the shutter release magnet.
Start the shutter. However, as mentioned above, the dry battery power source is nearing the end of its lifespan and its output voltage is unstable, so by the time the electric shutter circuit operates as described above and the shutter release magnet operates, the dry battery's life is nearing its end and its output voltage is unstable. The output voltage decreases and becomes below the reference voltage. Then, the power supply voltage determination circuit detects this, and the supply of dry battery power to the electric shutter circuit is cut off. Therefore, at that point, the power to the electric shutter circuit is turned off, and no further operation of the electric shutter circuit is performed. As a result, the operation of the shutter closing control magnet is also turned off, causing the shutter to close prematurely. This results in underexposed photographs not only in normal photography, but especially in long exposure photography. However, the photographer interprets this as a photograph taken with proper automatic exposure using the electric shutter. Also, even if this situation occurs, if you do not use the camera for a while, the output voltage of the dry cell battery will recover, and the voltage will return to normal before the next shot and the shutter will start. There is a possibility that the situation of closing immediately will continue many times. An object of the present invention is to eliminate such drawbacks by allowing the electric shutter circuit to continue the shutter operation to the end even if the power supply voltage drops below the reference voltage once the shutter is started. To provide electric shutters for cameras. According to the present invention, even if the dry battery power supply is nearing the end of its life and its output voltage is unstable, the operation of the electric shutter circuit is continued by maintaining the power supply after starting the shutter. This prevents the shutter from closing in the middle of shooting, resulting in underexposure, and from repeating such failures due to improper exposure. Hereinafter, the present invention will be specifically explained with reference to illustrated embodiments. The electric shutter circuit shown in Figure 1 includes an electric shutter start control circuit ES, a power supply holding circuit PS, a power supply voltage judgment circuit VC, a display circuit DS, an auto/self delay circuit AS, a magnet start circuit SR for shutter release, and a photometry control circuit. It consists of a circuit EC, a magnetic starting circuit SC for shutter closing control, and a DC power supply E. The electric shutter start control circuit ES controls the start of the electric shutter circuit, and consists of a series circuit consisting of a shutter release switch SW 1 and a resistor R 1, whose contacts are closed when the shutter button is pressed, and a series circuit of the shutter release switch SW ₁ and the resistor R ₁ . A series circuit consisting of a switch SW ₂ whose contact closes when the contact is closed, a resistor R ₄ and a transistor Q ₁ is
A capacitor is connected to both ends of the dry battery power supply E, and a capacitor is connected to both ends of the resistor _R1 .
It is configured by connecting a series circuit of C ₁ , resistors R ₂ and R ₃ . The base of the transistor _Q1 is connected to the connection point of the series-connected resistors _R2 and _R3 , and when the shutter button of the camera is pressed, the switch SW1 is closed and the power supply E is connected to the base of the transistor _Q1 . From, switch
Current flows through SW ₁ , capacitor C ₁ , and resistor R ₂ to the base of transistor Q ₁ , and transistor Q ₁ is turned on during the charging time of capacitor C ₁ . The resistor _R1 is for discharging the charge in the capacitor _C1 when the camera is not in use. The power supply holding circuit PS is the power supply voltage judgment circuit mentioned above.
VC, display circuit DS, auto-self delay circuit
It supplies and maintains the voltage of the power supply E to the four circuits AS and photometry control circuit EC.
The above judgment circuit VC, display circuit DS, delay circuit AS,
The four circuits of the control circuit EC are connected to a power line E _P connected to the positive terminal of the dry cell power supply E and a power line E _M connected to the negative terminal of the power supply E through a transistor _Q6 . Power line E _S
is connected between. This holding circuit PS consists of the above-mentioned transistor _Q6 , which functions as a power switch, and the same transistor Q6.
In order to drive Q ₆ , a series circuit consisting of a transistor Q ₂ and resistors R ₅ and R ₆ is connected to both ends of the power supply E, and the collector and emitter of the transistor Q 1 are connected to the collector and emitter of the transistor Q ₁ to maintain the connection with the power supply. It consists of a series circuit of transistors Q ₃ , Q ₄ , and Q ₅ connected between them, and a transistor Q ₃₁ connected in parallel with transistor Q ₃ . The bases of the above transistors Q ₅ and Q ₆ are connected to the connection point of the above resistors R ₅ and R ₆ , and the transistors
The collector current of Q ₂ is designed to flow.
Also, three transistors connected in series
Q ₃ , Q ₄ , Q ₅ form an AND circuit, and 3
Only when all of the transistors are on,
The base current of the transistor Q ₂ flows through the resistor R ₄ to the three series transistors Q ₃ , Q ₄ , and Q ₅ , and the collector current of the transistor _{Q 2} becomes the base current of the transistor Q ₆ . It is supposed to turn on and keep the power connected. Therefore, if even one of the three transistors turns off, the power supply is disconnected, and all the electric circuits between the power lines E _P and E _S become inactive. transistor Q ₃
When the power supply voltage determination circuit VC in the next stage detects that the power supply voltage is normal, it is turned on by applying the determination voltage signal, and the transistor _Q4 is turned on by the comparator _AM3 of the photometry control circuit EC.
The transistor Q5 is turned on by the output of the transistor Q2, and the transistor _Q5 is turned on by the signal from the transistor _Q2 . Transistor Q ₃₁ is
It is turned on by the high level output signal of comparator AM ₂ of delay circuit AS, and transistor Q ₃
Transistor _Q31 maintains the power supply connection even when the power supply is turned off. The power supply voltage judgment circuit VC is the power supply holding circuit PS mentioned above.
When the transistor _Q6 is turned on, the voltage of the power source E applied between the power line E _P connected to the positive terminal of the power source E and the power line E _S is higher than the reference voltage. The field effect transistors connected between the above power lines E _P and E _S respectively
A reference voltage generation circuit consisting of a series circuit of FET, semi-fixed resistor RV ₁ and resistor R ₇ , a voltage dividing circuit consisting of a series circuit of resistors R ₈ and R ₉ , and a comparator.
_AM1 , and a resistor _R10 connected between the output terminal of the comparator _AM1 and the base of the transistor _Q3 . A connection point a between the resistor R ₇ and the resistor RV ₁ is connected to the gate of the field effect transistor FET and to the negative input terminal of the comparator AM ₁ . The above field effect transistor
The series circuit of the FET, semi-fixed resistor RV ₁ and resistor R ₇ forms a constant voltage circuit that maintains the voltage at the connection point a constant, and changes the resistance value of the semi-fixed resistor RV ₁ to It serves to set the voltage at connection point a to a reference voltage value. The positive input terminal of comparator AM ₁ is connected to the above resistors R ₈ and R ₉ forming a voltage divider circuit.
The power supply voltage is applied to this positive input terminal. Comparator AM ₁ compares a voltage value proportional to the voltage of the power source E at the connection point b with a reference voltage value at the connection point a, and determines whether the voltage of the power source E is equal to or higher than the reference voltage value. If the voltage of power supply E is higher than the reference voltage value, the output of comparator _AM1 becomes high level, and if the voltage of power supply E is lower than the reference voltage value, the output of comparator AM1 becomes high level. The output of regulator AM ₁ will be at a low level. And the above resistor R ₁₀ is the comparator
When the output of AM ₁ is at a high level, the transistor Q ₃ is turned on, and when it is at a low level, the transistor Q ₃ is turned off to control the connection of the power supply. The display circuit DS includes a transistor Q ₅₀ and a resistor R ₅₁ connected between the power lines E _P and E _S , respectively.
and a series circuit of R ₅₂ , a series circuit of a resistor R ₅₃ , a light emitting diode D _L and a transistor Q ₅₁ ,
It further comprises a resistor R ₅₀ connected between the base of the transistor Q ₅₀ and the output terminal of the comparator AM ₁ of the judgment circuit VC.
When the output of AM ₁ is at a low level, the transistors Q ₅₀ and Q ₅₁ are turned on, and the light emitting diode D _L emits light, indicating that the voltage of the power source E is low, but when the voltage of the power source E is lower than the reference voltage. high, and when the output of comparator AM ₁ is at a high level,
The transistors Q ₅₀ and Q ₅₁ are turned off, and the light emitting diode _DL does not emit light. The auto/self delay circuit AS is used for normal automatic exposure shooting and self-timer shooting.
A circuit that delays each operation, and a resistor connected between the power supply lines E _P and E _S.
A time constant circuit consisting of a series circuit of R ₁₃ and a transistor Q ₈ , a self-timer setting switch SW ₃ , a resistor R ₁₅ and a capacitor C ₂ ,
A voltage divider circuit consisting of a series circuit of resistors _R18 and _R19 , a comparator _AM2 , a resistor _R16 connected to the other fixed terminal S of the self-timer setting switch _SW3 , and a comparator _AM2. Transistor connected between the positive input terminal and the power line E _S
Q ₉ and a resistor connected between the base of the transistor Q ₈ and the output of the comparator AM ₁
R ₁₂ , a transistor Q ₈₁ connected in parallel with the above transistor Q ₈ , and the same transistor Q ₈₁
a resistor R ₈₁ connected between the base of the comparator AM 2 and the output terminal of the comparator AM ₂ ; a resistor R ₁₄ connected between the base of the transistor Q ₉ and the collector of the transistor Q ₈ ; A resistor R ₁₁ is connected between the output terminal of _{AM 2} and the base of the transistor Q ₃₁ , and a resistor R 11 is connected between the positive input terminal of the comparator AM ₂ and the connection point of the resistor R ₁₅ and the capacitor C ₂ . Resistance R ₁₇
It is composed of. The negative input terminal of the comparator _AM2 is connected to the connection point between the resistors _R18 and _R19 . Also,
The above-mentioned self-timer setting switch SW ₃ has its movable contact W always connected to one fixed terminal A, and is normally used for automatic exposure photography, but when performing self-timer photography , switches the movable contact piece W to the other fixed terminal S.
Capacitor C ₂ forms a time constant circuit with resistor R ₁₅ or R ₁₆ , but resistor R ₁₆ has a large resistance value compared to resistor R ₁₅ , and the above-mentioned switch SW ₃ is movable. When the contact W is connected to the other fixed terminal S, the time constant of the resistor R ₁₆ and the capacitor C ₂ is designed to set the delay time for the self-timer, and the self-timer seconds are ,
It is around 8 to 10 seconds. However, in normal life, the movable contact piece W is connected to one fixed terminal A, and the time constant of the resistor R ₁₅ and capacitor C ₂ at this time is very small, only about a few milliseconds.
There is a delay in operation, but this has become almost imperceptible to the photographer. Comparator AM ₂ connects the charging voltage of capacitor C ₂ connected via resistor R ₁₇ to its positive input, and the voltage of the voltage divider circuit consisting of resistors R ₁₈ and R ₁₉ connected to its negative input. In comparison, when the charging voltage becomes higher than the voltage of the voltage divider circuit, the output of comparator AM ₂ becomes high level, and when it is low, the output becomes low level. The above transistor Q ₈₁ is connected via the resistor R ₈₁ to
The comparator _AM2 is turned on by the high level output signal, and even if the transistor _Q8 is turned off, the transistor _Q81 maintains the operating state of the delay circuit AS. Magnetic starting circuit SR for shutter release
is the magnet for releasing the shutter.
This is a circuit for starting Mg ₁ , and consists of a series circuit of a resistor R ₂₂ and a transistor Q ₁₀ connected to both ends of the power supply E, and a shutter release magnet connected to both ends of the transistor Q ₁₀ .
A series circuit of Mg ₁ , capacitor C ₃ , the base of the above transistor Q ₁₀ and the above comparator AM ₂
It consists of a resistor _R23 connected between the output terminal of the Transistor Q ₁₀ is driven by the high level output of the preceding comparator AM ₂ and turns on, causing the discharge current of capacitor C ₃ to flow through magnet Mg ₁ . In this embodiment, the magnet Mg ₁ is a well-known release type magnet, and as mentioned above, when a discharge current flows through the magnet Mg ₁ , the magnetic force generated thereby cancels out the magnetic force of the permanent magnet. The attraction force of the magnet Mg ₁ is removed and the shutter is released. The photometry control circuit EC determines the shutter time for proper exposure by photometry of the light receiving element CdS and generates a shutter close signal, and is connected between the power lines E _P and E _S , respectively. A time constant circuit consisting of a series circuit of capacitor C ₄ and photodetector CdS, a voltage dividing circuit consisting of a series circuit of semi-fixed resistor RV ₂ and resistor R ₂₄ , comparator AM ₃ , and the above capacitor C ₄ connected to both ends. a resistor R ₂₁ connected between the base of the transistor Q ₁₁ and the output terminal of the comparator AM ₂ , and between the output terminal of _{the comparator AM 3 and} the base of the transistor Q ₄ . It consists of a resistor R ₂₀ connected to. Transistor Q ₁₁ is the comparator
While the output of AM ₂ is at a low level, the base current flows and turns on, serving to short circuit capacitor C ₄ . And said comparator
When the output of AM ₂ becomes high level, the transistor Q ₁₁ is turned off, and a time constant circuit consisting of the capacitor C ₄ and the light receiving element CdS is activated. The negative input terminal of the comparator AM ₃ is connected to the connection point between the semi-fixed resistor RV ₂ and the resistor R ₂₄ , which form a voltage divider circuit, and the positive input terminal is connected to the connection point between the capacitor C ₄ and the photodetector CdS, which form a time constant circuit. and while the transistor Q ₁₁ is turned on at the low level output of the comparator AM ₂ and short-circuits the capacitor C ₄ , the voltage to the positive input terminal is equal to that of the power supply E. Since it is equal to the voltage and higher than the voltage from the voltage divider circuit to the negative input terminal above, the output of comparator AM ₃ is at a high level.
When the output of the comparator AM ₂ becomes high level, the transistor Q ₁₁ is turned off, and the short circuit of the capacitor C ₄ is removed, the time constant circuit is activated and the voltage to the positive input terminal of the comparator AM ₃ becomes As it starts to fall gradually and the voltage becomes lower than the voltage of the voltage divider circuit to the negative input, the output of the comparator AM ₃ switches to a low level. Note that the semi-fixed resistor RV ₂ is used to adjust the voltage of the voltage dividing circuit. The resistor R ₂₀ is for supplying the output of the comparator AM ₃ to the base of the power supply holding transistor Q _4. When the output of the comparator AM ₃ is at a high level, the transistor Q ₄ is turned on. When the output goes low, the transistor Q ₄ turns off, turning off the transistors Q ₂ and Q ₆ , and connects the power supply line between E _P and E _S. Disconnect the power supply. Magnetic starting circuit SC for shutter closing control
is for starting the magnet Mg ₂ that controls the closing timing of the opened shutter, and consists of a series circuit of the shutter closing control magnet Mg ₂ and the transistor Q ₁₂ , each connected to both ends of the power supply E.
It consists of a resistor _R25 connected between the base of the transistor _Q12 and the output terminal of the comparator _AM3 . Transistor Q ₁₂ is the comparator above
The high level output of AM ₃ normally turns it on, thereby also energizing the magnet Mg ₂ and putting it into operation. and the photometry control circuit
When the shutter time for proper exposure is determined by EC and the output of comparator AM ₃ becomes a low level, the transistor Q ₁₂ is turned off, magnet Mg ₂ becomes inactive, and the shutter is closed. . As described above, the electric circuit of the electric shutter of the present invention is constructed. Its operation will be explained next. To take pictures with a camera equipped with the above electric shutter circuit,
All you have to do is press the shutter button (not shown).
When this is pressed down, the release switch _SW1 is closed by the shutter release member.
When this is closed, the voltage of the power source E is applied to the capacitor C ₁ and the resistor through the contacts of the switch SW ₁ .
It is applied to the series circuit of R ₂ and the base and emitter of the transistor Q ₁ , and at the same time the capacitor C ₁ is charged, the transistor Q ₁ is turned on, and its collector current flows through the resistor R ₄ to the base of the transistor Q ₂ . flows into the transistor
Turn on _Q2 . When the transistor _Q2 is turned on, its collector current flows to the base of the transistor _Q6 , turning on the transistor _Q6 , and the power supply voltage judgment circuit VC and display circuit connected between the power supply lines E _P and E _S are connected. Supply voltage from power supply E to DS, auto-self delay circuit AS, and photometry control circuit EC to activate them. Also,
_The collector current of transistor Q ₂ also flows to the base of transistor Q ₅ , turning it on. Transistor Q ₄ is turned on by the high level output of comparator AM ₃ . As described above, when the transistor _Q6 is turned on and the voltage of the power supply E is applied between the power supply lines E _P and E _S , the comparator AM ₁ of the power supply voltage determination circuit VC first The voltage is compared with the reference voltage. In this case, when the voltage of power supply E is higher than the reference voltage, comparator AM ₁
The output of the transistor becomes high level, and the output of the transistor
Supplying the high level output to Q ₃ , turning on transistor Q ₃ , turning on transistor Q ₂ through resistor R ₄ in a series circuit with the transistors Q ₄ and Q ₅ , and keeping the power supply connected. At the same time, the high level signal is also supplied to the next stage, causing the electric shutter circuits in the next stage and below to continue operating. Further, when the voltage of the power supply E is lower than the reference voltage, the output of the comparator _AM1 remains at a low level, and the low level signal turns off the transistor _Q3 , so that the power supply holding circuit is not formed. Therefore, capacitor C ₁
When charging is completed and the base current of transistor Q ₁ stops flowing, transistor Q ₁ is turned off, which turns off transistor Q ₂ , and further turns off transistor Q ₆ , so that the power supply line E _P and The voltage of power source E is no longer applied across E _S , all circuits are turned off, and the electric shutter is not activated. Therefore, the shutter opening/closing member also does not operate. Now, when the voltage of the power supply E is higher than the reference voltage and the output of the comparator _AM1 becomes a high level, the high level output signal turns on the transistor _Q8 . When transistor Q ₈ turns on,
Transistor _Q9 is turned off. This transistor Q ₉ had been on until now, setting the positive input terminal of comparator AM ₂ to zero volts to prevent comparator AM ₂ from malfunctioning, but now transistor Q ₉ has turned off. By this, the charging voltage of the capacitor C ₂ of the time constant circuit is transferred to the comparator via the resistor R ₁₇ .
Transmitted to the positive input terminal of _AM2 . capacitor C ₂
When the movable contact piece W of the self-timer setting switch SW ₃ is connected to one fixed terminal A for automatic shooting, the charging voltage for 8 seconds to 10 seconds when connected to another fixed terminal S for
In about seconds, the voltage becomes higher than the voltage of the voltage divider circuit formed by the resistors R ₁₈ and R ₁₉ , and the output of the comparator AM ₂ changes from a low level to a high level. When the output of comparator AM ₂ goes high, its high level output signal is connected to resistor R ₁₁ and
Transistors Q ₃₁ and through R ₈₁ respectively
Turn on _Q81 . This transistor Q ₃₁ , Q ₈₁
are connected in parallel to the transistors Q ₃ and Q ₈ , respectively, and the voltage of the power source E, which exceeds the reference voltage value at the time of shutter release, is then consumed by the operation of the electric shutter circuit, When the voltage drops below the reference voltage value, the output of the comparator AM ₁ of the judgment circuit becomes low level, the transistors Q ₃ and Q ₈ are turned off, and the power supply holding circuit PS and the delay circuit AS are turned off. When turned off, the shutter operation is prevented from being interrupted, and the power supply holding circuit PS and the delay circuit AS continue to operate. The high level output of comparator AM ₁ above is
Also, the transistors Q ₅₀ and Q ₅₁ of the display circuit DS above
is off. When transistor _Q51 is turned off, light emitting diode DL does not emit light. However, as described above, after the voltage of the power source E is equal to or higher than the reference voltage value at the time of shutter release and the voltage supply of the power source E is held by the power supply holding circuit PS, the voltage of the power source E decreases and When the output of the comparator AM ₁ becomes low level, the transistors Q ₅₀ and Q ₅₁ are turned on and the light emitting diode DL emits light, indicating that the voltage of the power source E is below the reference voltage value. On the other hand, when the output of the comparator AM ₂ becomes high level, the high level output signal turns on the transistor Q ₁₀ and causes the discharge current of the capacitor C ₃ to flow through the shutter release magnet Mg ₁ . Then, the attraction force of the magnet Mg ₁ is removed, the shutter is released, and the shutter starts to open. The high level output signal of the comparator AM ₂ is also transmitted to the base of the transistor Q ₁₁ via the resistor R ₂₁ , turning off the transistor Q ₁₁ . When this is turned off, a charging current flows to the capacitor _C4 of the time constant circuit for photometry formed by the capacitor _C4 and the photodetector CdS. When the voltage from the time constant circuit supplied to the positive input terminal of the comparator AM ₃ reaches the shutter time for proper exposure by the light receiving element CdS, the resistor is supplied to the negative input terminal of the comparator AM ₃ . It will be lower than the voltage from the voltage divider circuit formed by RV ₂ and resistor R ₂₄ , and its output will go from high level to low level. Then, the transistor
_Q12 changes from the on state to the off state, and the shutter closing control magnet _Mg2 also changes from the operating state to the inactive state, thereby closing the shutter and ending the photographing. On the other hand, the comparator
The output signal of AM ₃ , which has changed from high level to low level, is transmitted to the base of transistor Q ₄ through resistor R ₂₀ , turning transistor Q ₄ of the power supply holding circuit PS from on to off, and performing the holding operation of the power supply connection. restore the condition. That is, when transistor Q ₄ is turned off, transistor Q ₂ is turned off, and transistor Q ₆ is also turned off.
Then, the negative terminal of the power supply E, which was connected to the power supply line E _S through the same transistor _Q6 , is disconnected, and the power supply voltage judgment connected to the power supply lines E _P and E _S is disconnected. The circuit VC, display circuit DS, auto-self delay circuit AS, and photometry control circuit EC are all turned off, and the electric shutter circuit shown in Figure 1 returns to its initial state. Further, the switch SW ₂ in the electric shutter start control circuit ES has its contact closed when the shutter is closed, and remains closed until the film is wound, turning off the transistor Q ₂ . Therefore, transistor Q ₆ also remains off, and even if you press the shutter button and turn on shutter release switch SW ₁ during this time, the electric shutter circuit will not operate. . Next, a second example of an electromagnetic release type electric shutter mechanism that is controlled by the electric shutter circuit to which the present invention operates as described above will be described.
This will be explained using figures. In FIG. 2, a disk-shaped shutter drive member 21 is fixed to one rotatable shaft 22, and one end 23a of a driving spring 23 wound around the shaft 22 is connected to the The drive member 21 is fixed, and the other end 23b is fixed to a charge member 29 that rotates in conjunction with the winding of the film. The driving spring 23 is adapted to increase its elasticity in conjunction with the winding of the film, thereby imparting a counterclockwise rotational driving force to the shutter driving member 21. The rotation of the drive member 21 due to this rotational driving force is caused by the locked arm 2 protruding from the drive member 21 in the radial direction before the shutter is operated.
1a is blocked by colliding with the inclined edge 25a of the start position regulating member 25 that is swingably supported by the support shaft 24, and in this blocked state, the shutter drive member 21 is at the starting position of the shutter operation. It has become possible to stand still. Inclined edge 25 of the start position regulating member 25
A is formed at the end of one arm of the regulating member 25, and the other arm 25b is adapted to be attracted to a shutter release magnet Mg ₁ which is constituted by a well-known release type electromagnet including a permanent magnet. . and,
This regulating member 25 is normally given the habit of rotating clockwise around the support shaft 24 due to the elasticity of the spring 30, so that the other arm 25b is attracted to the magnet Mg ₁ and tilted. The locked arm 21a abuts against the edge 25a, thereby stopping the shutter drive member 21 at the starting position. A control section 26a, which is one arm of the locking member 26 for determining the shutter time, is located on the rotation path of the locked arm 21a. The locking member 26 is swingably supported by a support shaft 27, and is given the habit of rotating counterclockwise around the support shaft 27 by the elasticity of a spring 28. The attracting piece 26b at the end of the other arm comes into contact with a shutter control magnet _Mg2 composed of an electromagnet, and is attracted to the magnet _Mg2 when the shutter is operated. Further, a driving pin 31 is implanted at a position close to the periphery of the upper end surface of the shutter driving member 21, and this pin 31 is a driven pin 31 formed by bending the lower end portion of the connecting rod 32 in the horizontal direction. It fits into a long hole 32b bored in the portion 32a. The connecting rod 32 is swingably supported by a shaft 33, and a shutter blade driving pin 34, which is planted at its upper end, is connected to both shutter blades 3.
They are simultaneously fitted into elongated holes 37a and 38a bored at the bases of 7 and 38. Both shutter blades 37,
38 has its base rotatably supported by shafts 35 and 36, and closes the photographing optical path 39 in the state shown in FIG. This shutter blade 37,3
Reference numeral 8 constitutes a so-called vario-type shutter, in which when the shutter drive member 21 rotates due to the release elasticity of the driving spring 23, the connecting rod 32 rotates around its shaft 33 via the drive pin 31. The optical path 39 is opened and closed as the lens oscillates. Next, the operation of the electric shutter described above will be explained with reference to the electric shutter circuit shown in FIG. 1 and the electric shutter mechanism shown in FIG. 2. FIG. 2 shows a state in which the shutter is charged in conjunction with film winding. In this state, since the driving spring 23 is stored, a force is applied to the shutter drive member 21 to rotate it counterclockwise. However, since the inclined edge 25a of the start position regulating member 25 restrained by the shutter release magnet Mg ₁ is located within the rotation path of the locked arm 21a, the The stop arms 21a abut each other, and the shutter drive member 21 remains stationary at the start position. In this state, to take a picture, it is sufficient to press a shutter button (not shown). When this is pressed down, the release switch _SW1 is closed. When this is closed, in the electric circuit shown in FIG. 1, transistor Q ₁ is turned on, transistor Q ₂ is turned on, and transistors Q ₅ and Q ₆ are also turned on. When the transistor _Q6 becomes conductive, an operating voltage is applied to the power supply line _E from the power supply E, and the power supply voltage determination circuit VC, display circuit DS, and auto-self circuits connected between the power supply lines E _P and E _S Power is connected to the delay circuit AS and photometry control circuit EC.
Then, comparator _AM1 of the power supply voltage judgment circuit VC compares the voltage of the power supply E with the reference voltage,
When the voltage of the power source E is higher than the reference voltage, the output of the comparator _AM1 becomes high level, turning on the transistor _Q3 and forming a holding circuit for the power source. In this case, the transistor Q ₄ has already been turned on by the high level output signal of the comparator AM ₃ of the photometric control circuit EC. When the power holding circuit is formed by turning on transistor _Q3 , the finger pressure is removed from the shutter button and the switch is turned on.
Even if SW ₁ is opened or capacitor C ₁ is fully charged and transistor Q ₁ is turned off, the power supply connection remains.
In this case, the transistors Q ₅₀ and Q ₅₁ of the display circuit DS remain off due to the high level output of the comparator AM ₁ , so the light emitting diode DL does not emit light. However, when the voltage of the power supply E is lower than the reference voltage, the output of the comparator _AM1 becomes a low level, so the transistor _Q3 is turned off, and a power supply holding circuit is not formed. When Q ₁ is turned off, the power supply is disconnected, all circuits connected between the power lines E _P and E _S are turned off, and the shutter is not activated. In this case, the transistors Q ₅₀ and Q ₅₁ of the display circuit DS are turned on by the low level output of the comparator AM ₁ , so the light emitting diode DL emits light;
When Q ₁ is turned off, the power connection is immediately cut off, so the light emitted from the light emitting diode DL immediately disappears. Particularly when the time constant of the capacitor C ₁ and resistor R ₂ is small, the power supply is instantaneously disconnected, so the light emitting diode DL only operates instantaneously and hardly emits light. Now, when the voltage of the power supply E is higher than the reference voltage value, the high level output of the comparator _AM1 turns on the transistor _Q8 , and as a result, the transistor _Q9 turns off. Then, the auto-self delay circuit AS operates as described above, and the output of its comparator _AM2 becomes high level. Then, due to the high level output signal,
The transistors Q ₃₁ and Q ₈₁ are turned on, and as described above, the off operation of the transistors Q ₃ and Q ₈ is covered by the on operation of the transistors Q ₃₁ and Q ₈₁ , and the power supply holding circuit PS and the delay circuit AS are respectively turned on. keep it in working condition. Therefore,
After this, even if the voltage of power supply E drops below the reference voltage value, the shutter operation will not be interrupted.
It is done normally. The above display circuit DS is the above comparator AM ₁
However, as mentioned above, when the voltage of the power supply E is low from the beginning and the holding circuit PS is not formed, the operation of the display circuit is interrupted instantaneously. However, as mentioned above, the power supply holding circuit
After the continuation of the operating state of PS is covered by the ON operation of transistor Q ₃₁ and the power supply holding circuit PS is completely formed, it is normally operated by the output signal of comparator AM ₁ of the above-mentioned judgment circuit VC. uninterrupted. Also, in this case, the power supply holding circuit
Since the transistor Q ₃₁ is connected in parallel with the transistor Q ₃ of the holding circuit PS to form the PS, the function of the power supply voltage judgment circuit VC can be operated normally. It's summery. Therefore, even if the voltage of the power supply E drops after this state, that state can be displayed. That is, if the voltage of the power supply E decreases after this state, the comparator AM ₁
Due to the low level output of , transistors Q ₅₀ and Q ₅₁ of the display circuit DS are both turned on, so that the light emitting diode _DL emits light. As mentioned above, this is because the dry batteries that make up power source E are nearing the end of their lifespan.
This indicates that the voltage is unstable, which means it's time to replace the battery.
Furthermore, if the voltage of the power supply E continues to be equal to or higher than the reference voltage value, the output of the comparator AM ₁ remains at a high level, so the transistors Q ₅₀ and Q ₅₁ remain off, and the light emitting diode D _L
does not emit light. The light emitting diode D _L explained above
The table below shows the relationship between the light emission of the light, the voltage of the power source E, and the timekeeping circuit PS, and these relationships will be clearly understood.

[Table] On the other hand, comparator AM ₃ of photometry control circuit EC
When the power source E is supplied through the transistor _Q6 , its output immediately becomes high level, so the transistor _Q12 is turned on, and a current flows through the magnet _Mg2 to excite it. Now, when the output of the comparator AM ₂ becomes high level, the transistor Q ₁₀ turns on, and the discharge current of the capacitor C ₃ flows all at once to the shutter release magnet Mg ₁ , and the attracting magnetic force of the release type magnet is increased. is demagnetized. When this is demagnetized, the other arm 25b of the start position regulating member 25 that was restrained by the magnet Mg ₁
becomes free, so that the inclined edge 25a is attached to the locked arm 2.
1a by the release elasticity of the driving spring 23, the start position regulating member 25 rotates counterclockwise around the support shaft 24 against the tensile force of the spring 30, and the inclined edge 25a and the locked arm 21a
The shutter drive member 21 is rotated counterclockwise by the release elasticity of the driving spring 23, and the shutter starts. When the shutter drive member 21 is unlocked and rotated counterclockwise, the connecting rod 32 is swung clockwise by the drive pin 31 integrated with the shutter drive member 21, and the shutter blades 37, 38 are rotated. The photographing optical path 39 is opened by the swinging movement of the connecting rod 32, and at a position where the locked arm 21a is locked with the control portion 26a of the locking member 26, the photographing optical path 39 is completely opened. On the other hand, the high level output signal of the comparator AM ₂ turns on the transistor Q ₁₀ and causes a degaussing current to flow through the magnet Mg ₁ , and at the same time turns off the transistor Q ₁₁ and starts the operation of the photometry control circuit EC. . This photometry control circuit EC integrates the amount of reflected light from the subject using a time constant circuit of a capacitor _C4 and a light receiving element CdS, and adds the integrated value to a comparator _AM3 . That is, the time constant of the above time constant circuit is determined by the capacitance of the capacitor _C4 being _C4 ', the light receiving element CdS
If the resistor Rcds is determined according to the photometric value of , then it becomes C ₄ '×Rcds, and as is well known, the time taken to charge the capacitor C ₄ by this time constant is the appropriate shutter time for the subject. . Then, as time passes due to the above charging, the capacitor
When the potential at the positive input terminal to comparator AM ₃ due to the charging potential of C ₄ reaches the divided potential of resistors RV ₂ and R ₂₄ , the output of comparator AM ₃ becomes a low level, and the shutter closing control magnet
Cut off the power to Mg ₂ and close the shutter. When the power to this magnet Mg ₂ is cut off,
Since the force that was attracting the attraction piece 26b of the locking member 26 disappears, the locked arm 21a of the shutter drive member 21 is moved by the spring 2 due to the elasticity of the driving spring 23.
8, the control part 26 of the locking member 26
a is retreated from the rotation path of the locked arm 21a. Then, when the shutter drive member 21 further rotates counterclockwise and completes one rotation to the start position shown in FIG. 2, the hold release switch is released by the locked arm 21a of the shutter drive member 21.
SW ₂ is closed. When this is closed, in the electric circuit shown in FIG. 1, transistor Q ₂ is turned off, and along with this, transistors Q ₅ and Q ₆ are turned off, and the power supply is released. Therefore, the current in the circuit is only the dark current of the transistor, and almost no current flows. Also, by turning off transistor _Q6 , the power supply voltage determination circuit VC and display circuit
Since the DS and auto-self delay circuit AS are also turned off, the capacitor _C3 is charged from the power supply E through the resistor _R22 and the magnet _Mg1 , and preparations for the next shooting are made. Furthermore, once the capacitor _C3 has finished charging, this charging current also disappears, so almost no current flows through the entire circuit. Then, due to the attraction force of the permanent magnet of magnet Mg ₁ , the start position regulating member 2 moves back to the initial position.
The locked arm 21a abuts against the inclined edge 25a of the drive member 21, and the drive member 21 stops rotating. Also,
The shutter blades 37 and 38 perform a closing operation by rotating counterclockwise after the locked arm 21a is disengaged from the control unit 26a, and when the driving member 21 is at the stop position, the shutter blades 37 and 38 close the photographing optical path 39. Close completely. After the automatic exposure photographing by the electric shutter is completed in this manner, by winding up the photographed film, the driving spring 23 is charged in conjunction with this, and preparations for the next photographing are made.

[Brief explanation of the drawing]

FIG. 1 is an electric circuit diagram of an electric shutter showing one embodiment of the present invention, and FIG. 2 is a perspective view of an electromagnetic release type electric shutter mechanism controlled by the electric shutter circuit of FIG. 1. . PS...Power supply holding circuit, SR...Magnetic starting circuit for shutter release, VC...Power supply voltage determination circuit, _Q3 , _Q6 ...Transistor, _AM1 ,
AM ₂ , AM ₃ ... Comparator, R ₁₁ ... Resistor,
E...Power source (dry battery).

Claims (1)

[Scope of Claims] 1. A power supply, a voltage determination circuit that constantly measures the power supply voltage while the power supply is being supplied with power, and generates an output when the power supply is equal to or higher than a reference voltage value; and a shutter upon receiving the output of the voltage determination circuit. A shutter release circuit that outputs a shutter release signal to the release electromagnet and holds this output, a photometry control circuit, and a shutter closing circuit that closes the shutter according to the output of this photometry control circuit are connected in parallel to each other. A switching circuit Q ₁ for starting the power supply, which is connected to the shutter release button and becomes activated when the release button is pressed down, a first switching circuit Q ₃ that becomes activated upon receiving the output of the voltage determination circuit, and a circuit for shutter release described above. a second switching circuit _Q31 that is activated upon receiving the output of the switching circuit Q31; and a voltage determination circuit that is activated when at least one of the power start-up switching circuit, the first switching circuit, and the second switching circuit is activated. An electric shutter for cameras consisting of energizing switching circuits Q ₂ and Q ₆ that connect the shutter release circuit, photometry control circuit, and shutter closing circuit to the power supply.