JPH0455291B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a self-timer device in a camera with a built-in strobe, and in particular, the light-emitting section of the built-in strobe device is located at a light-emitting position where power can be supplied to the strobe circuit section and at a storage position where power cannot be supplied to the strobe circuit section. A camera that moves to and from the strobe circuit, with at least a small portion of the movement automatically moving to the co-flashing position depending on the brightness of the subject, or a camera whose light emitting part does not move but moves to the strobe circuit part according to the brightness of the subject. The present invention relates to a self-timer device suitable for a camera with a built-in strobe whose power supply is automatically controlled.

Conventional configuration and its problems Conventionally, self-timer devices have been recognized as devices that allow the camera to start shooting after a predetermined set time, and the built-in strobe device is used or not used depending on the brightness of the subject as described above. Cameras with built-in flashes in which the status is automatically selected are also usually provided with such devices.

Now, if we consider the activation of the self-timer device in the camera with a built-in strobe, it has conventionally been extremely common to have the self-timer device activated in conjunction with the shutter release operation.

However, in a camera with a built-in strobe as described above, the measurement operation of the subject brightness for controlling the usage status of the built-in strobe device is also normally performed in conjunction with the shutter release operation.

That is, in reality, subject brightness measurement is performed with priority over activation of the self-timer device; for example,
When taking pictures using a self-timer device on a camera with a built-in strobe as described at the beginning, if the subject brightness is low, the strobe device is set to use before the self-timer device is activated, and the strobe device can fire. When this state is reached, the self-timer device is activated.

However, in conventional devices that operate as described above, subject brightness is not measured after the self-timer is activated; in other words, subject brightness is measured only when the shutter release operation is performed. Therefore, there was a problem in that the self-timer device could not follow changes in subject brightness during operation.

For this reason, in recent years, cameras with built-in strobes have appeared that can measure the brightness of a subject even when the self-timer device is in operation, and can select whether or not to use the built-in strobe device.

However, in the case of the above-mentioned camera, if the use of the built-in strobe device is selected while the self-timer device is operating, if the self-timer continues to operate and continues shooting, the built-in strobe device will be disabled. Although the flash unit is set in a state where it is in use, that is, the light emitting unit is moved and power is supplied to the strobe circuit, strobe devices usually require a predetermined period of time to supply a sufficient amount of light. Therefore, there is a risk that an underexposed photographing operation may be caused.

Therefore, when using the built-in strobe device when using the self-timer, the above-mentioned camera normally returns the state of the self-timer device to its initial state before operation, that is, performs a so-called reset, and then performs subsequent shooting operations. It is configured in such a way that it is prohibited.

Therefore, underexposure shooting operations are always prohibited.
If you wish to continue shooting using the self-timer device, check that the built-in flash device is able to supply sufficient light, and then set the self-timer device again to ensure proper exposure. This means that we can expect it to work.

However, even with the above-mentioned camera, it is not always necessary to reset the self-timer device, for example, if the built-in strobe device did not fire even though it was ready for use in the previous shooting operation. However, it is difficult to say that an operating system for smoothly performing photographing using the self-timer device has been formed.

That is, an operating system in which the self-timer device is reset whenever the use of the built-in strobe device is selected when using the self-timer device is not suitable for all situations, and an improvement is desired.

On the other hand, in recent years, structures have been developed in which the strobe circuit section is maintained in a state where it can emit light by some operation necessary for photographing, regardless of whether or not the built-in strobe device is used. Cameras equipped with a so-called pre-charging configuration, which can be charged in advance regardless of whether or not the strobe device is used, have also been put into practical use.

According to such a camera, if the self-timer device is used with the main capacitor precharged to the desired level, the timing of measuring the subject brightness and its height will affect the timing of using the built-in strobe device as described above. The problem of not being able to take pictures smoothly does not occur.

However, if the shooting operation for pre-charging or pre-charging is performed for the first time after firing the flash, etc., the self-timer device may not be able to fully charge the main capacitor. It is conceivable that the photographing operation is performed by the timer device, and in such a case, the above-mentioned problems will not be solved at all.

Purpose of the Invention It is an object of the present invention to take into account the problems of the prior art as described above, and to control the movement of the light emitting unit and the power supply operation to the strobe circuit according to the brightness of the subject, depending on whether or not the built-in strobe device is used. To provide a self-timer device which can form an extremely smooth photographing operation system that is suitable for a camera with a built-in strobe and which does not perform an underexposed photographing operation.

Another object of the present invention is to provide a self-timer device in which the continuation or reset of the photographing operation by the self-timer device can be controlled by the state of charge of the main capacitor in the strobe circuit section of the built-in strobe device.

Configuration of the Invention A self-timer device according to the present invention includes a self-mode setting means for selecting use of the self-timer device, a self-starting circuit that operates upon being supplied with a self-start signal and starts the timing operation of the timer circuit, and the above-mentioned timer circuit. self-operating means consisting of a circuit, and first and second actuators that operate when the use of the built-in strobe device is detected by a switch means that detects whether or not the built-in strobe device is in use, and that operate in reverse after a predetermined delay time. A delay means for outputting a signal, a voltage determination means for determining the state of charge of the main capacitor of the built-in strobe device based on the amount of light emitted, and outputs of the delay means and voltage determination means are supplied to the delay means. and a reset means for outputting a reset signal for the self-operating means only when the state of charge of the main capacitor within a period of time does not allow a sufficient amount of light to be emitted.

DESCRIPTION OF EMBODIMENTS FIG. 1 is a schematic electrical circuit diagram of a camera with a built-in flash having an embodiment of a self-timer device according to the present invention.

Note that the camera with a built-in strobe in this embodiment measures the subject brightness, for example, after opening the lens cover necessary for photographing.
It is configured so that the measurement is always performed at a predetermined period, and if the measurement results show that the subject brightness is low, below a predetermined level that requires the built-in strobe device to emit light, the light emitting part of the built-in strobe device moves to the predetermined light emitting position. It is assumed that the circuit section and the like are configured so as to be moved to an operable state.

In the figure, 1 is a self-mode setting switch that, when turned on, sets a state in which a well-known self-timer operation is performed in which the exposure operation is performed after a predetermined time has elapsed from an arbitrary point in time, and 2 is a self-timer device that measures the set time. A self-operating means is shown that includes a timer circuit 3 that makes decisions and a self-timer starting circuit 4 that controls the operation of the timer circuit 3.

The timer circuit 3 outputs a shooting start signal a that sets the shooting start point when the timer ends, and the self-timer starting circuit 4 is put into an operation ready state when the self-mode setting switch 1 is turned on. When a self-start signal is input to the timing terminal ₄₁ , the timer circuit 3 is operated to maintain the operating state until a high level reset signal is input to the reset terminal ₄₂ .

Reference numeral 5 indicates a middle press switch which is turned on by detecting the middle press operation of the shutter release button (not shown), and 6 operates to output a self-start signal b which starts the operation of the self-timer starting circuit 4 when the middle press switch 5 is turned on. At the same time, the photographing control means outputs a photographing operation signal c that causes the actual photographing operation to be performed in response to the previous photographing start signal a or a full press signal caused by a full press operation of a shutter release button (not shown) being supplied. ing.

The photographing control means 6 in this embodiment is configured such that the output of the above-mentioned photographing operation signals is prohibited by supplying low level signals to the inhibition input terminals 6 ₁ and 6 ₂ .

Reference numeral 7 designates a photometering means which operates in the manner described above and measures the subject brightness, and reference numeral 8 designates a movement control means which controls the movement of a light emitting section (not shown) based on the output of the photometering means 7.

9 is a movement detection switch for the light emitting part that is turned on only when the light emitting part moves to the light emitting position; 10 is a flash discharge tube 11 and an electric circuit part 12 such as a power supply part;
This figure shows a strobe device that is enabled to emit light when a movement detection switch 9 is turned on.

Reference numeral 13 denotes a reference clock circuit 14 which outputs a reference clock pulse signal of a predetermined period, and when the movement detection switch 9 is turned on, a first signal d and a first signal d, which are generated at different times in response to the clock output of the reference clock circuit 14, are output. 2 shows a delay means consisting of a shift register 15 which outputs a signal e of 2.

In this embodiment, the shift register 15 outputs high-level (hereinafter referred to as H) signals as the first and second signals d and e, that is, when the movement detection switch 9 is off. is configured such that both signals are at a low level (hereinafter referred to as L), and therefore the difference in the above-mentioned generation time is the difference in the rise time.

Reference numeral 16 indicates a voltage detection unit 17 that divides and detects the charging voltage of a main capacitor (not shown) included in the electric circuit unit 12 of the strobe device 10, and converts the unknown voltage V detected by the voltage detection unit 17 into a predetermined voltage _Vref.
A voltage determination means consisting of a comparator 18 for comparison with is shown.

19 is a NAND circuit supplied with the first signal d and the output signal of the comparator 18; 20 is supplied with the second signal e and the output signal of the NAND circuit 19;
NOR circuit, 21 is shooting operation signal c and NOR circuit 2
0 output signal is supplied and the output terminal is connected to the reset terminal 42 of the self-timer starting means 4, and the reset means ₂₂ is used to reset the self-timer starting circuit 4 and cancel the operation of the photographing operation means. It consists of

The operation of the self-timer device in the illustrated embodiment having the above configuration will be explained below.

First, a case where the subject brightness is high and the light emitting unit does not move will be described.

In this case, since the movement detection switch 9 is maintained in the off state as shown, the first and second signals d and e of the shift register 15 in the delay means 13 are maintained at L, respectively.

Therefore, the NAND circuit 19 always outputs an H signal regardless of the output of the comparator 18, and therefore the NOR circuit 20 also always outputs an L signal.

As a result, the H signal to the reset terminal ₄₂ of the self-timer starting circuit 3 and the L signal to the prohibition input terminal ₆₂ of the photographing control means 6 are not supplied, and the self-operating means 2 and the photographing control means 6 can operate. It will be in a state of

Therefore, if the middle press operation switch 5 is turned on while the self-mode setting switch 1 is turned on, the self-timer activation circuit 4 is activated by the output of the self-start signal b from the photographing control means 6, and the timer circuit 3 is activated. will start timing.

When the timer circuit 3 finishes counting a predetermined time, it outputs a photographing start signal a, and therefore, at this point, the photographing control means 6 receives the start signal a and outputs a photographing operation signal c, and starts the actual photographing operation. will be carried out.

The photographing operation signal c is sent to the _reset terminal 42 of the self-timer starting circuit 4 via the OR circuit 21.
Needless to say, the self-timer activation circuit 4 is reset.

As described above, when the subject brightness is high and the light emitting unit is not moving, the self-timer operation is performed extremely smoothly.

Next, a case will be described in which the subject brightness is low and the light emitting section moves.

The camera with a built-in strobe in this example is
Since the photometry operation is performed at a predetermined period, it goes without saying that the movement of the light emitting section may occur during or before the timer circuit 3 measures time, that is, before the self-operation. .

Now, when the light emitting part moves a distance, the movement detection switch 9 is turned on regardless of the timing of the movement, so the strobe device 10 and the delay means 13 start a predetermined operation. is brought into an operable state in which the discharge tube 11 can emit light, and the shift register 15 in the delay means 13 is activated in response to the clock output of the reference clock generating circuit 14 as shown in FIG. 2A. After the movement detection switch ₉ is turned on, indicated by t1, from time _t2 or _t3 the signals as shown in FIG. It will be output as signal e.

On the other hand, it goes without saying that the comparator 18 of the voltage determination means 16 also outputs a determination signal corresponding to the detection voltage of the voltage detection section 17 that detects the charging voltage of the main capacitor as the strobe device 10 operates. .

Therefore, the output level of the NAND circuit 19 will vary depending on the output level of the comparator 18.

That is, if the charging voltage of the main capacitor is too low to supply a sufficient amount of light emission and the voltage detected by the voltage detection section 17 is lower than the reference voltage _Vref , the comparator 18 will output an H signal. Therefore, the NAND circuit 19 inverts and outputs an L signal after the time _t2 when the first signal d shown in FIG. If the voltage is high enough to obtain the amount, the comparator 18 will output an L signal, so the NAND circuit 19
will output an H signal regardless of the state of the first signal d.

As is clear from FIG. 1, the signal output from the NAND circuit 19 is transmitted to the photographing control means 6 and
It will be supplied to the NOR circuit 20.

Therefore, the main capacitor is in an uncharged state.
Assuming that the NAND circuit 19 is outputting the L signal, the photographing control means 6 is prohibited from operating to generate the photographing operation signal c, and of course is placed in a state in which it cannot output the self-start signal b. become.

On the other hand, the output level of the NOR circuit 20 is varied depending on the output state of the NAND circuit 19 and the second signal e, that is, the output level of the NOR circuit 20 is varied depending on the output state of the NAND circuit 19 and the second signal e.
When the NAND circuit 19 outputs an L signal from t ₂ , the previous L signal is inverted to output an H signal, and the second signal e is output at time t ₃
Then, an operation is performed to return to the original state of outputting the L signal.

The operating relationship under the above conditions, that is, the operating state of the NAND circuit 19 and NOR circuit 20 when the main capacitor is not charged, is shown in Figure 2 E and F in detail. Needless to say.

Now, the H signal shown between time t ₂ and time t ₃ in FIG. The H signal output within the delay time t is
It will be supplied to the reset terminal ₄₁ of the self-timer starting circuit 4 via the OR circuit 21, and therefore the self-timer starting circuit 4 will be reset, and the self-operating means 2 consisting of the timer circuit 3 etc. will be rendered incapable of performing that action, regardless of its own state.

That is, regardless of whether the self-operating means 2 is in an operating state or not, if the main capacitor is in an uncharged state when the light emitting part moves, the self-operating means 2,
The operation of the photographing operation means 6 is reset and prohibited.

On the other hand, conversely, the charging voltage of the main capacitor is high.
This is a case where the NAND circuit 19 is outputting an H signal, but this state occurs when the luminance of the subject is high and the light emitting part is not moving, that is, when the delay means 1
3 does not operate and the first signal d is in the same state as outputting an L signal, so the NOR circuit 2
0 outputs an L signal, and the OR circuit 21 never outputs an H signal.

Therefore, the self-timer starting circuit 4 or the photographing control means 6 will not be reset, and even if the timer circuit 3 is in operation, its operation will not be stopped.

Furthermore, as described above, if the charging voltage of the main capacitor is high, the self-timer starting circuit 4 and the photographing control means 6 become operational, so if the operation is canceled due to the main capacitor not being charged as described above, It goes without saying that the self-timer operation can be performed by operating the middle press switch 5 again after the main capacitor has been charged until a sufficient amount of light is obtained.

The cases in which the subject brightness is high and low have been briefly described above, but the operation under special conditions that may actually occur will now be described. That is, in a camera with a built-in strobe like the one of the present invention, the operation of the electric circuit section 12 of the built-in strobe device is DC-DC.
Since this is the charging operation of the main capacitor by the converter circuit, it is a significant noise source and is known to cause the terminal voltage of the power supply to drop rapidly, albeit temporarily. Since the circuit operation is stopped while the circuit is in operation, when the light emitting part is in the protruding state, the timer circuit 3
It is conceivable that the voltage may drop below a predetermined voltage during timing.

In such a case, the operation of the self-timer starting circuit 4, etc. should be canceled by following the explanation of the circuit operation described above, but in the self-timer device according to the present invention, the voltage drop described above is as shown in FIGS. The above-described release operation is not performed unless it occurs within the delay time between the first signal d and the second signal e shown in FIG.

This is because the time measured by the timer circuit 3 is usually about 10 seconds, and the voltage value of the main capacitor that drops during this 10 seconds or so is small, so even if the above situation occurs, the photographic effect will not be affected. This is because we believe that it is unlikely to have an extremely large impact.

That is, the self-timer device according to the present invention can be said to be a device that disables the self-timer operation only when the main capacitor is uncharged during the delay period of the first and second signals, which can be considered as the time when the light emitting part is ejected. That's why.

Effects of the Invention The self-timer device according to the present invention automatically selects whether or not to use the built-in strobe device depending on the subject brightness. Since the operation is disabled only when the capacitor is uncharged, when the charging voltage of the main capacitor is high, the self-timer device can be used to perform shooting operations extremely smoothly. Therefore, it has practical value, especially in cameras with a built-in strobe that has a so-called pre-charging function that performs some kind of charging operation of the main capacitor regardless of whether or not the strobe device is used.

[Brief explanation of the drawing]

FIG. 1 is a schematic electrical circuit diagram of a camera with a built-in flash having an embodiment of a self-timer device according to the present invention, and FIG. 2 is a signal waveform diagram for explaining the operation of the embodiment shown in FIG. ing. DESCRIPTION OF SYMBOLS 1...Self mode selection switch, 2...Self operating means, 3...Timer circuit, 4...Self activation circuit, 6...Photography control means, 9...Movement detection switch, 10...Strobe device, 13... ... Delay means, 16 ... Voltage determination means, 17 ... Voltage detection section, 18 ... Comparator.

Claims (1)

[Scope of Claims] 1. A self-timer device for a photographic camera incorporating a strobe device whose use is automatically selected depending on the brightness of a subject, the self-timer device selecting a self-timer mode for photographing using the self-timer device. and a self-mode setting means for prohibiting the operation by the full-press operation of the photographing control means that causes various operations such as exposure operation to be performed by the full-press operation of the shutter button, and when the self-mode is selected by the self-mode setting means. A self-starting circuit that receives the self-start signal from the shooting control output to output a self-lift signal when the shutter button is pressed mid-press and starts operation; and an output signal when the self-starting circuit is in operation is supplied to start timekeeping. self-operating means comprising a timer circuit that supplies a photographing start signal to the photographing control means after completion of the photographing; a switch means for detecting whether or not the strobe device is in use; and a switch means for detecting when the strobe device is in use. Delay means for outputting first and second signals that are inverted with a predetermined delay time due to the operation of the means, and comparison with a reference signal based on the amount of light emitted to obtain the charging voltage of the main capacitor of the strobe device. voltage determining means for determining whether the battery is uncharged or fully charged; a first logic circuit to which the first signal and the output signal of the voltage determining means are supplied; and the second signal and the first logic circuit; includes a second logic circuit to which the output of the logic circuit is supplied, and only when the determination result of the voltage determination means within the delay time is that the battery is not charged, a reset signal for the self-operation means and an operation prohibition of the photographing control means are provided. A self-timer device comprising reset means for outputting a signal. 2. The delay means includes a reference clock circuit that outputs a clock pulse signal of a predetermined cycle, and a switch means that is activated when the strobe device is detected and has a delay time equal to the cycle at the inversion timing in response to the clock pulse signal. The self-timer device according to claim 1, comprising a shift register that outputs a first signal and a second signal. 3. The voltage determination means includes a voltage detection unit that divides and detects the charging voltage of the main capacitor of the strobe device;
The self-timer device according to claim 1, further comprising a comparator that compares the output voltage of the voltage detection section with a reference voltage based on the amount of light emitted.