JPH0522896B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a camera with a built-in or attachable flash device. With this camera, preparatory operations for flash photography,
For example, the main activation switch is activated in conjunction with the operation of manual operation means, such as retracting the shielding member placed in front of the photographic lens out of the optical path of the lens, or protruding (pop-up) the built-in flash. When activated, it momentarily excites and activates the DC/DC converter, thereby charging the main capacitor.

Conventionally, this type of camera is known from Japanese Patent Application Laid-open No. 159625/1983. This camera momentarily generates a startup signal for the DC/DC converter in conjunction with manual operation, and in response to that signal, the DC/DC converter starts operating and charges the main capacitor, and the charging current reaches a predetermined value. DC/
It is configured to suppress the current flowing to the DC converter (including stopping its operation).

However, in such a flash device, the manual operation means, such as the operation to retract the shielding member or pop up the flash light emitting part, is not performed completely, and the main start switch remains in the ON position. The activation signal may continue to be generated. In this case, the charging voltage to the main capacitor reaches a predetermined value and the charging current also decreases, but the charging current continues to flow. Therefore, there is a problem in that even though the charging voltage has reached a predetermined value before the flash is emitted, a wasteful current flows and the power source battery is exhausted.

SUMMARY OF THE INVENTION An object of the present invention is to provide a camera with a flash device that does not require any special operating means and consumes less battery.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a specific circuit example of an electronic flash device that can be built into the camera of the present invention.

A power supply 1 supplies power to the entire illustrated circuit via a power switch 2. Transistor 3, transformer 4,
Capacitor 5 and diode 6 constitute a DC/DC converter. Moreover, the transistor 3 is
Functions as a control circuit that controls the operation of the DC/DC converter. A switch 8 connected to the primary coil of the transformer 4 via a resistor 7 is the main starting switch. The main capacitor 9 is charged with a voltage for flashlight emission. Transistor 10, resistor 11, switch 12, transistor 13, switch 14,
Resistor 15, transistor 16, switch 17, resistors 18, 19, and 20, transistor 21, and terminal 22 constitute a sub-starting circuit for starting the DC/DC converter. Transistor 23, resistor 24, 2
5, 26 and 27, capacitor 28, switch 2
9 constitutes a sub-trigger circuit for flashlight emission. Thyristor 30, capacitor 31 and transformer 33 constitute a main trigger circuit. A neon display tube 35 connected to the DC/DC converter via a resistor 34 indicates that the main capacitor 9 is fully charged. Both trigger circuits are flash discharge tubes 36.
Controls flash emission. The power switch 47 supplies power to the exposure control circuit 48. This switch 4
7 constitutes a shutter release locking means. That is, first, in conjunction with the lens shielding release operation,
Power switch 2 is turned on and the DC/DC converter starts operating. On the other hand, the release lock means switch 47 is turned OFF at this time, and the exposure control circuit 48 is inoperative. That is, at this time, even if the shutter release is performed, the front curtain does not run. In this way, the shutter release is locked.

The release lock is not limited to being electrically operated as described above, but may be one that mechanically prevents the release button 114 from being pressed. Next, the main start switch 8 is turned OFF and the switch 47 is turned ON, so that the exposure control circuit 48 becomes operable and the shutter release lock is released.

The details of the configuration will be explained below.

The main start switch 8 is a switch that starts oscillation of the DC/DC converter, and is momentarily turned on in conjunction with the shielding release operation of the shielding member. The secondary winding of the step-up transformer 4 is connected to the base (control electrode) of the transistor 3. Further, the secondary output of the step-up transformer 4 charges the main capacitor 9 via the diode 6.

The starting switch 8 includes an auxiliary starting transistor 1.
0 are connected in parallel. The base of the transistor 10 is connected to the power supply battery 1 through a resistor 11, and a normally closed switch 12 controls turning on and off of the transistor 10. Switch 12 (flash)
It is turned off in conjunction with the operation to prepare for the next (flash) photo shoot after the photo shoot is completed.

The switch 8 further includes a forced operation transistor 1.
3 are connected in parallel. The base of the transistor 13 is connected to the power supply battery 1 via a switch 14 and a resistor 15. The switch 14 is a flash device (not shown) that protrudes from the camera body (pop-up).
It is turned on in conjunction with. The transistor 16 controls on/off of the transistor 13, and when the selector switch 17 selects the terminal 17a, the power supply voltage divided by the resistor 19 is applied to the resistor 1.
8 and is always on, and when the selector switch 17 selects the terminal 17b, the neon display tube 35 lights up when the main capacitor 9 is fully charged (details will be described later). The voltage generated across the resistor 19 when the resistor 18
is applied to its base through the circuit to turn it on. This changeover switch 17 selects the terminal 17a when the flash device is stored in the camera body, and selects the terminal 17b when the flash device protrudes from the camera body, for example in conjunction with the protrusion operation.

The transistor 21 has the changeover switch 17 connected to the terminal 1.
7b, if the neon display tube 35 is off, the bias voltage from the resistors 19 and 20 is cut off and turned off, generating a Hi level release lock signal at the terminal 22. Further, the transistor 21 is turned on when the neon display tube 35 is off and when the selection switch 17 selects the terminal 17a, and generates a release lock release signal at the L0 level at the terminal ₂₂ .

Transistor 23, resistors 24 to 27, noise absorbing capacitor 28 and synchro contact 29 constitute an auxiliary trigger circuit for thyristor 30. This trigger circuit is supplied with power from the power supply battery 1 via the switch 14. The charge charged in the trigger capacitor 31 via the resistor 32 and the trigger transformer 33 is transferred to the synchro contact 29 contact and the thyristor 3.
0 is turned on, a discharge occurs and the flash discharge tube 36 emits light.

FIG. 2 is a schematic diagram showing an embodiment of a camera with a built-in flash device according to the present invention. In the figure, a shielding member 10
0 is a manual operation member, which can be manually slid up and down the front surface of the lens 101, and is connected to the conductor 102.
is fixed. In the illustrated state, the shielding member 1
00 shields the photographing lens 101, and the conductor 102 is not in contact with the terminals 103, 104, 105, and 106. That is, the main start switch 8, the power switch 2, and the switch 47 constituting the shutter release means are turned off, and the shutter release is locked. This position is the first position. Before photographing, when the shielding member 100 is pushed down, the conductor 102 first connects the terminals 103 and 1.
04 and turn on the power switch 2. By using the terminal 103 as a ground line, the switch 2 is turned on even when the shielding member 100 is completely pushed down. Next, while the shielding member 100 is being pushed down, the conductor 102 is connected to the terminal 1.
03, 105 and turn on the main start switch 8 for a moment. This position is the second position,
At this point, the DC/DC converter starts operating, and on the other hand, the switch 47 is OFF, so the shutter release is locked. Further, when the shielding member 100 is pushed down, the conductor 102 and the terminal 1
03 and 106, turn on switch 47, and release the shutter release lock. That is, this position is the third position, where the main starting switch 8 is turned OFF, and then when the charging voltage reaches a predetermined value, the charging current decreases and the transistor is turned off.
OFF, and the DC/DC converter stops operating. The flash device 108 has pins 110 and 111 fitted into grooves provided in the camera body 109, and can be slid up and down. In the storage position of the flash device 108 shown in the second figure (flash photography not ready state), the switch 1 is
4 is off, and the selector switch 17 selects the terminal 17a. Next, when the flash device 108 is projected upward (flash photography preparation state), the selector switch 17 selects the terminal 17b by the pin 110, and the switch 14 is turned on by the pin 111.

The release lever 112 biased upward by the spring 113 is pushed down against the spring 113 by pressing down the release button 114 to actuate the release plate 115. The shutter is released by operating the release plate 115. The release lock member 116 is rotated clockwise by the excitation of the electromagnet Mg and locks the protrusion 112a. This prevents the shutter release. Electromagnet Mg
is excited when the terminal 22 becomes Hi level. For example, the terminal 22 becomes Hi level when charging is not completed.

Next, the operation will be explained.

(1) To release the shielding of the lens 101 shown in FIG. 2, push the shielding member 100 downward from the first position shown. First, the second position is reached, the conductor 102 contacts the terminals 103 and 104, the power switch 2 is turned on, and the circuit is powered on. Next, when the member 100 is pushed down further, the third position is reached and the conductor 102 is connected to the terminal 10.
3, 104 and momentarily contacts the terminal 105. By this, the main start switch 8
turns on momentarily, the DC/DC converter operates, and the main capacitor 9 is charged. On the other hand, the switch 47 is turned OFF and the shutter release is locked. Next, when the member 100 is further pushed down, the conductor 102 is moved to the terminal 10.
3, 104, disconnects from the terminal 105, and contacts the terminal 106. This position is the third position, and main start switch 8 is OFF.
On the other hand, the shutter release lock is released.

According to this configuration and operation, charging is always started by the camera's shooting preparation operation, that is, by the unshielding operation of the lens shielding member 100, so that when switching from shooting without using the flash device to using the flash device, charging is always started. Since the charging waiting time is shortened, you can take quick photos. Also, since oscillation automatically stops, battery consumption due to forgetting to turn off the power switch is significantly reduced.

(2) Next, in the above configuration, once the oscillation has stopped, the oscillation cannot be restarted except by turning on the switch 8 again to start the oscillation. Therefore, for example, once a flash is emitted for flash photography, re-oscillation does not start. This problem is solved by transistor 10 and switch 12. That is, in the embodiment of FIG. 1, the switch 12 is
This is a normally closed switch that is linked to the shutter release mechanism or film winding mechanism and is turned off when it is detected that the flash photography has ended. A transistor 10 connected in parallel with the switch 8 is biased from the power source 1 through a resistor 11, and is cut off when the switch 12 is on. Suppose now that flash photography has ended and oscillation has stopped. At this time, when the switch 12 is turned off in conjunction with, for example, release of the shutter release button or the start of film winding, the transistor 10 is turned on and starts oscillation for boosting the voltage instead of the switch 8. When considering interlocking with the release operation as an example of the implementation of the normally closed switch 12, it is sufficient to turn on the release button normally during the stroke of the release button, that is, without touching it with a finger, and turn it off with a slight stroke after touching the release button.

Further, according to the illustrated embodiment, boost oscillation is restarted by shutter release operation, winding operation, etc., regardless of whether or not the flash device 108 protrudes. supply power to the flashlight 1
If the switch 14 is turned on in conjunction with the protrusion of the flasher 108, re-oscillation of the DC/DC converter will occur only when the flasher 108 is in use.

(3) By the way, in the above case the oscillation automatically stops as the charging current of the main capacitor 9 decreases.
In the DC/DC converter, as the voltage of the power supply battery 1 decreases, its stop voltage gradually decreases, and there is a possibility that the boosting voltage will eventually be stopped before reaching the voltage that allows light emission. Therefore, it is necessary to forcibly oscillate up to a voltage that allows light emission, and then automatically stop the oscillation. In this case, however, it is sufficient to carry out the process only when the flash unit 108 is protruding, that is, when the flash unit is in use (in the illustrated embodiment, this depends on the configuration), but it may of course be carried out regardless of whether the flash unit 108 is protruding or not.

Now, when the flash device 108 is in the retracted state, the changeover switch 17 selects the terminal 17a. At this time, since the resistor 19 is connected to the power supply battery 1, the transistor 16 is turned on, and as a result, the transistor 13 is turned off. Therefore, flashlight 1
When 08 is in the stored state, the DC/DC converter is not forced to oscillate.

Next, when the flash device 108 is projected, the changeover switch 17 selects the terminal 17b. As a result, the charging completion display circuit including the resistor 34 and the neon display tube 35 is closed. Further, when the switch 14 is turned on by the projection of the flashlight 108, the base of the transistor 13 is connected to the power supply battery 1 via the resistor 15. When the main capacitor 9 is not fully charged, the neon display tube 35 does not light up, so no current flows through the resistor 19. Transistor 16 is therefore off, and as a result transistor 13 is on. Turning on transistor 13 causes the DC/DC converter to start oscillating instead of switch 8.

When the charging of the main capacitor 9 is completed, the neon display tube 35 lights up, and the lighting current causes a voltage drop across the resistor 19, which is applied to the base of the transistor 16 via the resistor 18, so that the transistor 16 is turned on. Become. Therefore, the transistor 13, which was on until the neon display tube 35 was turned on, is turned off, and the oscillation state of the DC/DC converter becomes the same as when the switch 8 is turned off. In this case, if the voltage of the power supply battery 1 is high enough, the neon display tube 35 lights up and the oscillation continues to some extent even if the transistor 13 is turned off. Thereafter, the feedback current to transistor 3 decreases and this oscillation automatically stops. Further, when the voltage of the power supply battery 1 is low, the oscillation stops at the same time as the transistor 13 turns off, that is, the neon display tube 35 lights up.

(4) Furthermore, in cameras with built-in flash devices, DC/DC
It is necessary to provide a mechanism to lock the shutter release while the converter is oscillating. In the illustrated embodiment, a changeover switch 17, a resistor 1
9, 20, transistor 21, and signal terminal 2
2 shows a configuration in which the release lock is released by lighting the neon display tube 35. The state of the signal terminal 22 is Hi level and the release is locked.
The configuration is such that the lock is released at the _L0 level. When the changeover switch 17 is on the 17b side, when the display tube 35 is turned on, the voltage generated in the resistor 19 turns on the transistor 21 through the resistor 20, and the signal terminal 22 goes to the _L0 level and the release lock can be released. Before the display tube 35 lights up, the transistor 21 is turned off and the terminal 2
2 is Hi level, ie, release lock.
Further, when the flash device 108 is stored, the changeover switch 17 is connected to the terminal 17a. Since the voltage from the power supply 1 is directly applied to the terminal 17a, the transistor 21 is always on.
That is, the terminal 22 is at the _L0 level, and the release lock is released.

(5) Resistor 32, thyristor 30, trigger coil 3
3. The capacitor 31 constitutes the main trigger circuit for the flash discharge tube 36. By turning on the thyristor 30, the secondary output of the trigger coil 33 is applied to the discharge tube 36, causing it to emit light. Thyristor 3
The auxiliary trigger circuit for triggering 0 is supplied with power from the primary side of the step-up transformer via switch 14. Therefore, the auxiliary trigger circuit operates only when the flashlight 108 is projected. When the synchro switch 29 is turned on, the transistor 23 is turned on via the resistor 25, and the divided voltages of the resistors 27 and 28 are applied to the gate of the thyristor 30, which turns on and causes the flash discharge tube 36 to emit light. Resistor 24 is a leak cut resistance.

In this way, the drop in the charging voltage of the main capacitor 9 due to leakage can be reduced compared to the conventional case where power is supplied to the auxiliary trigger circuit for the thyristor 30 from the secondary side of the DC/DC converter. . In other words, in a device that automatically stops the oscillation of the DC/DC converter upon completion of charging of the main capacitor 9, the charge stored in the main capacitor 9 only decreases due to leakage after the oscillation is stopped, so the boost It is necessary to connect no load to the secondary side of the transformer 4 as much as possible. Therefore, the above problem can be solved by supplying power to the auxiliary trigger circuit for the thyristor 30 from the primary side of the step-up transformer.

FIG. 3 shows a second embodiment obtained by modifying the circuit block of FIG. 1.

In the first embodiment, when the flash device 108 is ejected, the display tube 35 is turned on and the transistor 1 is turned on.
3 is turned off, the base circuit of transistor 3 is released, and the oscillation of the DC/DC converter is automatically stopped. In this case, the electric charge of the main capacitor 9 is consumed by the lighting current of the display tube 35, and the charging voltage of the main capacitor 9 eventually becomes unable to maintain the lighting of the display tube 35. Therefore, the display tube 35 is turned off and the transistor 13 is turned on again, restarting the oscillation of the DC/DC converter. It is obvious that if such a situation is repeated, the power supply 1 will be consumed. The second embodiment shown in FIG. 3 improves this.

First, the switch 14 is turned on by the flash 108 protruding. The switch 12 remains on until the camera starts preparing for the next flash photography. The transistor 37 is a forced oscillation transistor connected in parallel with the switch 8.

Now, when the changeover switch 17 selects the terminal 17b, charging of the main capacitor 9 progresses, and when the display tube 35 lights up, the transistor 16 turns on. As a result, transistor 42 is turned on through resistor 45, transistor 39 is turned on through resistor 40, and transistor 37 is turned off. Therefore, upon completion of charging
Oscillation of the DC/DC converter is automatically stopped.
Next, when the display tube 35 is turned off, the transistor 16 remains on because it is biased through the resistor 46. In other words, by making the transistors 16 and 42 a bistable circuit,
The base circuit of the transistor 3 is opened at the stage when the display tube 35 is turned on, and thereafter, even if the display tube 35 is turned off, it is prevented from re-oscillating.
Note that the bistable circuit may be achieved using a thyristor.

Further, the switch 12 is the above-mentioned switch, and in this case is used to release the latch of a bistable circuit. In other words, switch 1 is turned on in response to preparations for the next light shooting.
When transistor 2 is turned off and transistor 16 is turned off, transistor 39 is turned off, transistor 37 is turned on through resistor 38, and oscillation starts again. Therefore, the switch 12 also serves to restart the oscillation after the flash is emitted, but in FIG. 3, the switch 12 is configured so that the restart is performed only when the flash device 108 is projected.

In the above embodiment, the switch 8 is turned on for a moment in conjunction with the movement of the shielding member 100 to move the lens out of the photographing optical path, but the switch 8 is not limited to this and can be turned on in conjunction with the pop-up of the flash device 108. It is a good thing.

According to the present invention as described above, since the main capacitor is charged whenever the camera is in the shooting mode, not only can quick shots be taken more quickly when switching to flash photography, but also the flash 1
Since the voltage increase of 08 is automatically stopped, there is no consumption of the power supply, and furthermore, due to the interlocking relationship with the camera, the functions of the built-in flash device 108, such as restarting oscillation, can be fully utilized.

In this embodiment, only the photographing lens shielding member is used as the manual operation means, but it is also possible to use a winding lever or a dedicated manual operation member as the manual operation means. can. In the former case, the shutter release is initially locked, the main start switch is turned on during winding, and when winding is completed, the main start switch is turned off and the shutter release lock is released. Configure. In the latter case, a slide button or the like is used as a special manual operation member, the shutter release is initially locked, and the first stroke of the slide turns on the main start switch. Then, at the second stroke, the main start switch is turned OFF and the shutter release lock is released.

As described above, according to the present invention, when the operating member is moved from the position in which photographing is not possible to the position in which photographing is possible, the main activation switch of the main condenser for flashlight emission is operated in conjunction with this movement. The shutter release is locked until this movement is completed. When the movement is completed, the shutter release can be performed and the main start switch is deactivated.

Therefore, when the main activation switch is on, that is, when the operation member is not fully moved, the shutter release is locked, giving a warning to the photographer. Upon receiving this warning, the photographer completes the movement of the operating member in order to release the lock.
Once the movement is complete, the activation switch is cut off and the main activation signal disappears, eliminating the problem of charging current continuing to flow idly even after the charging voltage reaches a predetermined value, thus preventing unnecessary power consumption. be able to.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a specific circuit example of a flash device that can be built into the camera of the present invention, FIG. 2 is a diagram showing an embodiment of the camera of the present invention, and FIG. It is a figure which shows the example of a modification of the circuit shown in 1st figure. Explanation of symbols of main parts, main capacitor...
9. DC/DC converter...3,4,5,6, Main start switch...8, Flash device...108, Release lock means...47, Manual operation means...10
0. Control circuit...3.

Claims (1)

[Scope of Claims] 1. A main capacitor for flashlight emission, a DC/DC converter that boosts the DC power supply voltage to charge the main capacitor, and is activated to start the DC/DC converter and start the charging. A main start switch, and after the charging starts, charging is maintained even if the main start switch becomes inoperable, and when the charging current to the main capacitor decreases below a predetermined value, the DC/DC
A flash device including a control circuit that suppresses the operation of the DC converter, a release lock means that locks the shutter release, and at least two states, one in which photography is not possible and one in which photography is possible.
a first position in which the main activation switch is inactivated and the shutter release lock means is activated in the process of moving the operating member; a second position in which both the main activation switch and the shutter release locking means are actuated; and a third position in which the main activation switch is inactivated and the shutter release is unlocked by the shutter release locking means. A camera with a flash having a manual operating means capable of at least the following positions: