JPS628029Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to a shutter control circuit for a camera.

(Prior Art) In the case of a camera, since the exposure operation is always required to be controlled based on a stable photometric output, it is necessary to activate the photometric circuit in advance before starting exposure.

For this reason, the photometry circuit is normally activated by the first stroke of the release button, and the exposure operation is started by the second stroke.

However, even in this configuration, if the first stroke operation and the second stroke operation are performed within a short period of time, there is a risk that the exposure operation will be started before the photometric output is stabilized.

For this reason, a method has been proposed in which a timer circuit is provided that is activated when the second stroke operation is performed, and the release operation (exposure start operation) is started after a time regulated by the timer circuit.

If a camera employing the above method is to have a self-time shooting function, it must be provided with a timer circuit for the self-timer in addition to the timer circuit for normal shooting, resulting in two timers. A circuit is required, which causes the circuit configuration to become larger.

(Summary of the invention) The present invention was made in view of the above matters, and includes a counting circuit that counts pulses, a content of the counting circuit that is detected, and a count value of the circuit that is at least equal to the photometric information.
- a first detection circuit that outputs a release signal when the delay time reaches a first value longer than the time required for D conversion; a second detection circuit that outputs a release signal when the value of and by selecting the second detection circuit to perform a release operation for self-time photography, a single counting circuit as a timer circuit can be used for both normal and self-time shooting, This solves the above-mentioned problems and allows accurate exposure to be obtained at all times.

(Embodiment) FIG. 1 is a block diagram showing an embodiment of a digitally controlled camera according to the present invention, and the portion surrounded by dotted lines shows the circuit configuration built into the camera body.
Note that MD is an electric drive device and EF is an electronic flash device, and these are attached to the camera as necessary.
The camera circuit is an integrated circuit (LSI) that constitutes a sequence control section and an automatic exposure control section, and _P1 to _P17 are input/output terminals to the integrated circuit and external individual component connection terminals. is an integrated circuit (LSI) that constitutes the photometry section, arithmetic section, and time control section _.
~ _P36 is its input/output and external component terminals. M
are information display meters, Mg ₁ , Mg ₂ , and Mg ₃ are each electromagnetic magnets, Tr ₁ is a transistor for the power supply holding circuit from the power supply, LED1 to LED3 are display light emitting diodes, Sw ₁ to _{Sw 7} are switches, VR ₁ ~
VR ₆ is a variable resistor for information settings and other settings, and BAT is a power battery.

In the figure, Sw ₁ is a switch that is turned on at the first stroke of the shutter release operation, Sw ₂ is a switch that is turned on at the second stroke of the shutter release operation, Sw ₃ is a switch that is turned on when the bulb is exposed, and Sw ₄ is a count switch that is turned off when the shutter is released, and Sw ₆ is a switch for switching between auto and manual shooting, which is turned on during manual shooting. Sw ₇ is a switch for self-timer shooting that constitutes a mode selection means for selecting between self-mode and normal mode, and is turned on when the timer is used. Sw ₅ is a switch that alternately switches between film winding operation and camera shooting operation when taking pictures using the electric drive device MD.It switches to the NC side when winding is completed, and to the NO side when the shutter trailing curtain has finished running. Change.
Mg ₁ is a magnet for automatic exposure control, Mg ₂ is a magnet for starting camera operation, and Mg ₃ is a magnet for shutter speed control.

In the camera shown in Figure 1, photometry, calculations, and time control are performed in an analog manner using circuit elements.
Aperture control for automatic exposure and sequential control of various photographing modes are digitally performed by circuit elements. Details regarding these operations will be given when explaining the detailed circuit diagrams of FIGS. 2 and 3.

FIG. 2 is a circuit connection diagram showing an embodiment of the photometry section, calculation section, and time control section of the camera according to the present invention. External components, input/output, and power supply are connected to this via terminals _P18 to _P36 . In the figure, _AR1 to _AR3 and _AR5 to _AR9 are operational amplifiers, _CP4 to _CP6 are comparators, and _AR5 and _CP6 are controlled by control inputs (arrows). 301 is a constant voltage source, 302 is a switching circuit, and SPD is a photometric silicon photodiode. _D3 is a log diode to obtain logarithmic compression characteristics. The external individual parts R ₃₃ is a posister, C ₄ and VR ₂ are circuits to eliminate rapid fluctuations in photometric values due to flicker of the light source illuminating the subject, and VR ₃ is a variable resistor for setting shutter speed information and film sensitivity information. , VR ₄ is a variable resistor for inputting lens aperture correction information, M is a display meter, VR ₅ is a variable resistor for adjusting the seconds when shooting at the speed of light, VR ₆ is a variable resistor for setting the shutter seconds, C ₅ is a variable resistor for setting the shutter seconds. It is a capacitor in a timed circuit.

Next, the operation of the circuit shown in FIG. 2 will be explained. First, by releasing the shutter, switch SW ₁ is turned on, which turns on transistor TR _1.
(Fig. 1) is turned on, the circuit is connected to the terminal
A power supply battery (BAT in FIG. 1) is supplied with power between P ₃₆ and P ₂₉ via a power supply holding circuit, and the device becomes operational. As a result, the light-receiving photovoltaic element SPD, which receives light from the subject through the camera lens, generates a photocurrent corresponding to the brightness of the subject. This signal is amplified by an operational amplifier AR ₂ which has a logarithmic element D ₃ in its return path, and brightness information (BV) is produced at its output. In order to compensate for changes in the log diode D ₃ due to temperature, an operational amplifier AR ₁ with a diode D ₂ having the same characteristics as D ₃ is provided in the feedback path, and a posistor R ₃₃ is provided on the output side. Furthermore, the output from AR ₂ is input to operational amplifier AR ₃ via Posistor R ₃₃ , where the high frequency components of the signal are attenuated by the characteristics of C ₄ and VR ₂ , and the output fluctuations due to the above-mentioned flicker are removed. It will be destroyed. The brightness information (BV) from the AR ₃ is input to the inverting input terminal of the operational amplifier AR ₅ via a resistor R ₂₉ . Also, shutter time information (TV) and film sensitivity information (SV) are input to this terminal of the _AR5 , set to a variable resistor _VR3 , and these information are calculated by the _AR5 . For this reason
Aperture step number information _VΔAV is outputted to the output of AR ₅ , which is taken out from terminal _P23 and sent to the sequence control and automatic exposure control circuit as shown in FIG.
Also, this aperture step number information V△ _AV is combined with the output of AR ₆ of the aperture value information (AVO) of the lens set to VR ₄ , and the amplifier AR ₇ , and the information corresponding to the aperture value ( AV) is obtained, and this is displayed, for example, in the viewfinder by the aperture value display meter M. Also, as will be described later, when the magnet Mg ₂ that performs the camera start operation is excited, the signal is sent from the terminal P ₂₈ to the comparator CP ₆ to control CP ₆ , and the output from P ₂₇ excites the magnet Mg ₃ . to hold the second shutter curtain. When the shutter starts, the switch Sw ₄ turns off in conjunction with the start of the shutter front curtain, and charging of the capacitor C ₅ starts through the resistors VR ₅ and VR ₆ of the time constant circuit, and the terminal voltage of the comparator CP ₆ is changed. Applied to non-inverting input. This signal and the voltage from the switch 302 were divided by R ₂₆ and R ₂₇ , and this divided voltage and the reference voltage were compared by CP ₆ , and when they matched, CP ₆ was inverted to hold the rear curtain. Mg ₃ is demagnetized and the rear curtain runs. When photography is completed in this manner and the rear curtain of the shutter is braked, the changeover switch _Sw5 shown in FIG. 1 is switched to the NO side and the circuit is reset. The circuit surrounded by the dashed-dotted line is for controlling the aperture according to the distance information when shooting with the EF strobe, and switching the shutter speed to the strobe-only time, and its output controls the AR ₅ and the switch. 302.

FIG. 3 is a circuit connection diagram showing details of the circuit portion in FIG. 1. The figure shows an embodiment of the sequence control section and automatic exposure control section of the apparatus according to the present invention, and the portion surrounded by dotted lines is configured as an LSI. The circuit is configured as a digital control circuit, and P ₁ to _{P 17} are LSI terminals to which external individual components or circuits as shown are connected, respectively. In the figure, 1 to 20 are flip-flops, and these flip-flops constitute a binary counter.
The binary counter updates (steps) its contents by counting clocks and sequentially outputs control signals for sequentially controlling display and exposure operations according to the updating (stepping) state of the counter. Configure a counting circuit as a circuit.

P is preset input terminal, 1...9...20...
is the output, and CP is the clock pulse input terminal.
That is, when input P is logic "1", n is "1", n
becomes “0”. OSC is a clock pulse oscillator that oscillates clock pulses with a period determined by the time constant of resistor _R3 and capacitor _C3 . 308 is AD-
It is a DA comparator, A to G are its binary counters, and LAD is a resistor network. 303 is a power up clear circuit, 304 is a one-shot circuit, 305, 306 and 307 are flip-flop circuits, and 101 to 121 are flip-flop circuits.
NAND gate, 201 to 213 are inverters,
AR ₄ is an operational amplifier, and CP ₁ , CP ₂ , CP ₃ and CP ₇ are comparators.

Next, the operation shown in FIG. 3 will be explained.

(1) The camera has now completed winding, the first stroke of the release has been operated, and switch SW ₅ changes from NO to NC when the winding operation is complete.
Assume that it has been switched to . For this reason, the first
Press down on the stroke to turn on switch SW ₃ .
Transistor Tr ₁ of the power supply circuit is turned on, power supply voltage is supplied between terminals P ₁₇ P ₅ of the circuit, and the circuit is in an operating state. ( _E1 becomes "1") In this state, the OSC is activated and a clock pulse is supplied from the OSC to the counter. Also, when E ₁ is supplied to the circuit, capacitor C ₁ is charged, so transistor Tr ₂ is initially off and then turned on, so transistor Tr ₃
It says it's on for a moment. For this reason, the output of the power up clear circuit 303 becomes "0" for a moment, and the NAND
The output of 109 momentarily becomes "1" and the counter is preset to the initial value (initial state). Flip-flop (FF) 305 is also preset to an initial state, ie, _E2 is set to "1". Further, _{the inverted output 2 of} E2 sets the FF 306 to its initial state, and the output _E3 becomes "1". Also, the inverted output of E ₃
At _{step 3} , the FF 307 is also set to the initial state, and the output _E4 is set to "1". With these
The preset input of the AD-DA converter 308, ie, the output of the NAND 121, becomes "1" and the counters A to G are preset. Also, since _E2 is "1", the operational amplifier _AR4 is controlled thereby and its output is connected to ground. Therefore, since the output of CP ₁ is "1", the magnet Mg ₁ for automatic exposure control (AE) is not excited in this state. As described above, in state (1), E ₁ , E ₂ , E ₃ and E ₄ are all "1".

(2) When the shooting operation is started by operating the second stroke of the release from the state of (1), SW ₂ is turned on in conjunction with the operation of the second stroke. When SW ₂ is turned on, the output of I _V 202 becomes “1”, and the output of I _V 201 is also turned on when SW ₅ is turned on.
Since it is connected to , it becomes "1", and in this state, the divided voltage of the power supply voltage E ₁ and the constant voltage V _c are compared by the comparator CP ₇ , and the divided voltage value of E ₁ becomes V _c Since the output of CP ₇ is "1" when it is sufficiently high compared to (the power supply voltage is sufficient), these signals cause all the inputs of NAND 107 to become "1", and 107 outputs "0".

Now the output of 102 becomes “1”, so FF
305 is inverted and its output E ₂ changes from "1" to "0". Also, by the output of 102, I _V 203
The output changes from "1" to "0" and the base resistors R ₁ and R ₂ of Tr ₁ are connected to ground through terminal P ₁₄ , so even if switch SW ₁ is turned off, Tr ₁ is kept in the on state and the circuit continues. power is maintained. As a result of the above, E ₂ becomes "0", so the output ₂ of I _V 204 becomes "1", and the output of the one-shot circuit 304 becomes "0" by the delay time due to I _V 205, 206, 207. Therefore, the output of NAND 109 momentarily becomes "1" and counters 1 to 20 are preset again, and then NAND 109 is inverted from "1" to "0" and starts counting clock pulses from CP. Also, when E ₂ becomes “0”, AD-DA converter 3
The control of operational amplifier AR ₄ of 08 is released, and AR ₄
The output of is removed from the ground condition. This allows the output of AR ₄ to be transmitted to the input end of CP ₁ . As mentioned above, counters A to G are while ₂ is “0”, i.e.
Since it is in a preset state until E ₂ becomes "0", a high potential is being output from the resistor network LAD at the time E ₂ becomes "0". Therefore, the output of AR ₄ at this point is at a high potential, and CP ₁ where E ₂ becomes "0" is inverted and outputs "0". Yotsute AE magnet Mg ₁
is excited. Also, for comparator CP ₃
Since the high potential from AR ₄ is applied, CP ₃ outputs “1”, and counter A
Since ~G is preset, the output Q _A ~
Q _G is “1”, _A to _G are “0”,
The output of NAND119 is also "1". Therefore, when E ₂ becomes “0”, the input of NAND120 becomes
It becomes “1” other than ₁ , and NAND120 outputs the signal from output ₁ of counters 1 to 20 to AD-DA.
Inform comparator counters A to G.

Assuming that the auto shooting mode is currently selected (SW ₆ is off), the converter 308
The output of the NAND 121 is "1" and the counters A to G maintain their preset states. Also, when the auto shooting mode is switched (SW ₆ is off), the output of NAND121 changes from "1" to "0", the preset state is canceled, and counters A to G are set to NAND as described above.
₁ signal (pulse) output through 120
Start counting. This makes the operational amplifier
When the output of AR ₄ falls stepwise and the signal V△AV from the photometry circuit becomes equal to the output of this AR ₄ , converter CP ₃ inverts and outputs "0", which has no relation to output ₁ of NAND 120. “1” to
is output, the counting operations of counters A to G are stopped, and digital values corresponding to VΔAV are stored in counters A to G. Note that NAND12
By controlling CP ₃ with an output of 0, the influence of noise during counting by the counter is removed.

As described above, by the second stroke operation, a digital value corresponding to the aperture value VΔAV is stored in the counters A to G, and control of the release operation is also started.

(3) When using self-timer. At this time, the switch _SW7 as a mode selection means is on, so the output of the Iv208 is "1". On the other hand, counters 1 to 20 are the second
Since the counting operation is restarted after the stroke, the counter output is changing. Therefore, when the counter outputs ₁₈ and ₂₀ both become "1", the output of the NAND 110 changes from "1" to "0". As a result, NAND112 outputs "1", and the output of I _V 213 becomes "0", resulting in 104
is “1” and E ₂ is also “0” due to the action of the second stroke, that is, ₂ has become “1”.
The FF 306 is inverted and its output _E3 changes from "1" to "0". Therefore, NAND 113 outputs "0", the output of NAND 109 becomes "1", and counters 1 to 20 are preset again.
When the counter is preset, ₁ to ₂₀ become "0", so NAND112 becomes "0",
Therefore, since NAND113 returns to “1”, NAND
The output of 109 becomes "0" and counting is restarted. Therefore, from the time E ₃ changes from "1" to "0" until both ₇ and ₉ become "1", NAND118 becomes "0" and Mg ₂ is excited, which activates the camera start member and starts the shooting operation. Start.

In other words, as mentioned above, the output E ₃ of FF306 becomes after E ₂ becomes “0” in the second stroke.
Since the output becomes "0" only after the outputs of ₁₉ and ₂₀ become "1", the NAND118 outputs "0" only after the time required for the outputs of ₁₉ and ₂₀ to become "1" after the second stroke. electromagnet
Mg ₂ (constituting the camera's starting means) is excited to activate the camera's starting member linked to the magnet. Therefore, when using the timer, the contents of the counter are ₁₈ and ₂₀ from the second stroke.
The camera is not activated until both of the counters become "1" (second value), and the release operation is performed only when the contents of the counter reach the second value. Therefore, the counting time of the counter until the second value is reached becomes the self-timer time. Note that the NAND 110 constitutes a second detection circuit that detects the contents of the counter and outputs "0" as a release signal when the contents of the counter reach a second value.

(4) When not using the self-timer and in auto shooting mode At this time, switch SW ₇ is turned off. Therefore, the output of I _V 208 is “0”, I _V 20
The output of 9 is "1", and when the outputs ₈ , ₉ and ₁₀ from the counter all become "1", the output of NAND111 changes from "1" to "0", and from then on, the same as when using the self-timer. hand
The output E ₃ of the FF 306 becomes "0". As a result, the output _E3 of the FF 306 is inverted from "1" to "0" when all of ₈ , ₉ , _{and 10} become "1" from the second stroke of the release. In other words, when the self-timer is not used, E ₃ from the second stroke of the release has a canter of ₈ , ₉ , _10.
After counting until both become "1", they become "0", so the electromagnet Mg ₂ (constituting the camera's starting means) is excited in a shorter time than when using the self-timer described above, and the camera starts operating. The activation member is activated and the exposure operation begins. Therefore, in the normal shooting mode, ₈ , ₉ , and ₁₀ as the contents of the counter are all "1" from the second stroke.
When the state becomes (first value), the camera is activated. Since the time it takes for the counter to reach the first value is extremely short,
The exposure operation will be started immediately after the second stroke operation.

Here, to further explain the above-mentioned first value, this time is
It is set to be longer than the time required to change the photometric information from an analog value to a digital value. That is, AD-DA converter 308
For the conversion to
The above first value is determined at the reversal timing of the outputs of flip-flops ₈ to ₁₀ of counters 1 to 20, so the first value is A
-It takes longer than the time required for D conversion.

Note that the NAND 111 constitutes a first detection circuit that detects the contents of the counter and sends out an output "0" as a release signal when the contents of the counter reach the first value. Also, when E ₂ becomes “0” in the second stage of release, NAND 1
The output of 15 and 116 becomes “1” and LED1
and the display by LED2 is turned off.

Also, when using the self-timer, when E ₂ becomes "0", ₂ becomes "1", and while E ₃ is "1",
When SW ₇ is on, when both ₁₄ and ₁₅ become "1", the output of NAND 117 becomes "0" and LED ₃ blinks through terminal _P7 . LED ₃ blinks to indicate that the self-timer is in use, and when E ₃ becomes “0” when the timer operation ends, NAND 1
The output of 17 becomes "1" and LED ₃ turns off.

When the timer operation ends and E ₃ changes from "1" to "0" as described above, the output of _IV 211 becomes "1" and the output E ₄ of FF 307 becomes "1". Also, since ₃ is “1”, until both counter outputs ₇ and ₉ become “1”,
The output of NAND 118 becomes "0", and as mentioned above, the camera start magnet Mg ₂ is excited and the camera starts shooting, and when both ₇ and ₉ become "1", the output of NAND 114 becomes "0". The excitation of Mg ₂ is cut off.

(5) Operations after Mg ₂ is excited and photographing operation is started When Mg ₂ is excited as described above, the camera activation member that is linked to this is activated. Also, the Mg ₂ excitation signal is applied to the control terminal (P ₂₈ ) of the comparator circuit CP ₂ in Figure 2, and the output of CP ₆ becomes "0".
Mg ₃ is excited. As a result, the shutter rear curtain is held. At the same time, FF307
is reversed and E ₄ changes from “1” to “0” and becomes NAND
Set the output of 109 to “1” and set counters 1 to 2.
Set 0 to preset state.

When the camera activation member operates as described above,
In conjunction with this, a known diaphragm control mechanism operates to perform diaphragm diaphragm and mirror up. The operating state (diaphragm state) of the above aperture control mechanism is detected as a change in the resistance value of VR ₁ that is linked to the aperture control mechanism, and the comparator CP ₁ compares the resistance value and
The output of AR ₄ and the reference value V _c are compared, and when the resistance value of VR ₁ becomes a value corresponding to the output of AR ₄ , that is, the aperture value calculated as above, CP ₁ becomes "1". is output, demagnetizes the AE control magnet MG ₁ , and stops the aperture control mechanism.
End aperture control.

At this time, the shutter front curtain is moved by a member not shown, and when the shutter front curtain is moved, switch SW ₄ shown in FIG. 2 is turned off, and capacitor C ₅ is charged via resistors VR ₅ and VR ₆ , and the set shutter is After a few seconds, CP ₆ is reversed, Mg ₃ is de-energized, the shutter rear curtain runs, and the shooting operation is completed.

[Effect of idea]

As described above, the shutter control circuit according to the present invention includes the first detection circuit that detects the count value of the counter and generates a release signal when the content of the counter reaches the first value; A second detection circuit is provided that generates a release signal when the counting operation of the counter progresses further and reaches a second value, and the first detection circuit is activated in normal shooting mode and the second detection circuit is activated in self-mode. Since it is designed to be activated selectively, one counting circuit can serve both as a timer for normal photography and a timer for self-time use.

Further, in the shutter control circuit according to the present invention, even in the normal shooting mode, the release signal is generated by providing a delay time at the first value, and this first value is set at least in the light metering information A. Since the time is set to be longer than the time required for -D conversion, accurate exposure can always be performed no matter what conditions the release operation is performed.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment of a camera using a self-timer circuit according to the present invention, Fig. 2 is a circuit connection diagram showing details of the circuit in Fig. 1, and Fig. 3 is a circuit diagram showing the details of the circuit in Fig. 1. It is a circuit connection diagram showing details. ...sequence control and automatic exposure control,
...Photometering, arithmetic and seconds control unit, OSC...Pulse oscillator, 1 to 20...Counter, SW ₇ ...
Switch for self-timer shooting, 110, 11
1...NAND gate, 308...AD-DA converter.

Claims (1)

[Scope of utility model registration request] A release operation member that generates a first signal by a first release operation and a second signal by a second subsequent operation, and a release operation member that generates photometric information from a light receiving element by generation of the first signal. a photometric means for detecting as an analog value; an A-D conversion circuit that converts the photometric information of the analog value into a digital value in response to the second signal;
In the camera that performs an exposure operation based on the photometric information converted into the digital value after the generation of the signal, the second operation is performed by the second operation of the release operation member.
a counting circuit that counts reference pulses after the generation of a signal; and a counting circuit that detects the contents of the counting circuit and uses the contents of the counting circuit in a counting operation for at least A-D conversion in the A-D converting circuit. a first detection circuit that outputs a release signal when a first delay time determined using the output of an intermediate stage selected as a delay circuit longer than the time; and a first detection circuit that detects the contents of the counting circuit; A second circuit that outputs a release signal as a self-timer time when the content of the counting circuit reaches a second delay time determined using the output of a subsequent stage selected as a delay time longer than the first delay time. a second detection circuit, a selection switch for selecting the first or second detection circuit, and activation of the exposure operation of the camera in response to a release signal from the detection circuit selected by the selection switch. A shutter control circuit for a camera, comprising a starting circuit.