JPH0559414B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an improvement in a strobe device for a camera, particularly an automatic type camera with a built-in strobe.

PRIOR ART In fully automatic cameras, i.e. cameras that incorporate an automatic exposure control device and a strobe, and in some cases an autofocus device, the strobe is set separately for various combinations of subject brightness and subject distance. He was deciding whether or not to emit light.

By the way, photography is done under various scenes and conditions, and dividing these various conditions into smaller sections and determining the optimal photography and parameters for each case complicates the camera automation system. It has the disadvantage of becoming Further, even if the optimum parameters are determined, good photographs cannot always be obtained because there are always exceptions in each case and there are photometry or distance measurement errors. On the contrary, the more detailed the shooting conditions are, the higher the probability of producing a "failed" photo. For this reason, conventional automatic cameras, which make various subdivided combinations of subject brightness and subject distance, and decide whether or not to fire the strobe according to each combination, suffer from poor overall quality. I had problems getting good photos.

Purpose of the Invention Therefore, the present invention solves the above-mentioned problems in conventional automatic cameras, and solves the problem that a large current may flow in the initial stage when charging a strobe for flash emission. voltage drops,
To provide a strobe device for a camera that does not cause trouble with a control system or other parts and cause failure in taking pictures.

SUMMARY OF THE INVENTION The above object is to provide a strobe device for a camera that shares a power source with a microcomputer that controls multiple functions of the camera, including a charging circuit that charges the strobe, and a charging circuit of the power source that allows the microcomputer to operate. a power supply voltage detection circuit that detects a first voltage level and a second voltage level that is higher than the first voltage level; and a charging control circuit that stops charging the strobe when the strobe is detected, and starts charging the strobe when the power supply voltage detection circuit detects that the voltage level has returned to the second voltage level. This is achieved by the camera's strobe device.

EXAMPLES The present invention will be explained below with reference to examples shown in the drawings.

FIG. 1 is a front view of a specific example of the present invention, in which 1 is a camera body, 2 is a slide cover that can be slid in the direction of arrow A, 3 is a strobe light emitting section provided on this slide cover, 4 is a photographic lens, and 5 is a front view of a specific example of the present invention. 1 is a release button, 6 is a viewfinder, 7 is a metering window of an automatic exposure control device, 8 is a light projection window of an automatic focusing device, and 9 is a light receiving window of the automatic focusing device. Slide the slide cover 2 in the direction of arrow A and align it with the main body 1, and the lens 4, viewfinder 6, various windows 7, 8,
9 will all be hidden by a slide cover. The camera shown in the figure is a camera using a disk film, and 10 is a lever for opening and closing the light shielding plate of the disk film cartridge. This lever is a back cover opening/closing lever, and by raising it, the back cover is unlocked.

Then, when a disk film cartridge is loaded, the back cover is closed, and the lever 10 is pushed down to the state shown in the figure, the back cover is locked and the cartridge light-shielding plate is opened.

Figure 2 is a block diagram of a specific example of the present invention;
The figure is a detailed circuit diagram.

In the figure, A is a logic control circuit consisting of a CMOS one-chip microcomputer (hereinafter referred to as microcomputer). B is the distance measurement circuit, which includes the light emitting diode LED1 for projecting light and the distance measurement sensor SD.
Consisting of Although the sensor SD is omitted in the diagram, it consists of two phototransistors and a processing circuit, and it measures the distance to the subject by comparing the outputs of the two phototransistors.

C is a photometric circuit for automatic exposure control, which uses a photoconductive element.
It consists of a CdS and a comparator _C1 , and this comparator _C1 determines whether the subject is bright or dark. D is a power supply voltage detection circuit, which consists of a constant voltage element _D1 and a comparator _C2 , and prohibits strobe charging when the microcomputer power supply voltage VDD becomes lower than a predetermined value (for example, 3.2 volts) during strobe charging. .
This prohibition control is automatically performed within the strobe circuit, as will be explained later.

E is a power supply control circuit, which includes switching elements TR ₁ ,
Consists of TR ₂ . For example, the first release switch S ₁
When turned ON, TR ₂ becomes conductive and supplies power to the microcomputer, photometry circuit, etc. Similarly, when TR ₂ becomes conductive, strobe charging is prohibited and the motor brake circuit operates. In addition, the power supplies VDD and VCC reset the microcomputer through the reset circuit K, and after this reset, the terminals of the microcomputer are first reset.
A power hold signal is output from PH, and the power supply voltage
VDD is self-held until a predetermined operation is completed.

F is a strobe circuit. Since the strobe circuit is well known, its explanation will be omitted, but since this circuit is related to the power supply voltage detection circuit D, this point will be explained. A switching element _TR3 , which controls ON/OFF of a booster circuit composed of an oscillation transistor _TR4 and coils _L1 and _L2 , is controlled by an STP signal from a microcomputer and a comparator _C2 . That is, even if the strobe is being charged by the STP signal, when the voltage VDD becomes lower than a predetermined voltage, the comparator _C2 becomes LOW level, the switching element _TR3 becomes conductive, and the oscillation transistor _TR4 becomes conductive.
becomes non-conductive and prohibits charging.

The minimum operating voltage of the microcomputer used in this example is approximately 3V, and operation at lower voltages is not guaranteed. However, at the beginning of strobe charging, the starting current causes the power supply voltage to VDD.
It is known that it is possible for the voltage to drop below 3V. Therefore, if the power supply voltage VDD attempts to drop below 3V, it is necessary to temporarily suspend charging to prevent the power supply voltage from dropping.

Due to the operation of comparator _C2 , even when charging is temporarily interrupted, the microcomputer's charging command,
That is, the STP signal continues and the strobe circuit can charge when the power supply voltage is restored and comparator _C2 goes HIGH. In reality, by repeating this operation, the strobe is gradually charged, the charging current decreases, and charging becomes possible under conditions where the current voltage VDD does not fall below 3V, and the desired charging voltage is reached. .

A comparison of the strobe charging mode described above with a conventional example is shown in FIG. 4 (FIG. 4A, operating mode in the specific example in FIG. 3, and FIG. 4B in the conventional example).

Conventional power supply voltage detection circuits measure the open circuit voltage of the battery or the battery voltage with a load current of several milliamps flowing before actually operating the slot machine, etc., and depending on the results, either display a warning or display a warning. A common method was to lock the release. However, according to this method, it is necessary to take into consideration the internal resistance of the battery, load conditions, etc., and perform release locking, etc., while the battery has some remaining power in order to guarantee operation. In the illustrated embodiment, by detecting the power supply voltage when the strobe is actually operating, including the internal resistance of the battery, load conditions, etc., it is possible to use the battery to its maximum capacity.

Also, when the motor is operating, it can be temporarily interrupted in the same manner as described above.

G is the motor circuit, 4 transistors
It consists of TR ₅ , TR ₆ , TR ₇ , and TR ₈ , and when a signal is output from terminal CW of the microcomputer, transistors TR ₆ and TR ₈ become conductive, causing the motor M to rotate forward, and a signal is output from terminal CCW. When this happens, transistors TR ₅ and TR ₇ become conductive, causing the motor M to rotate in reverse. Note that an electromagnetic brake is applied to the motor when the motor stops rotating in the normal direction.

As shown in FIG. 3, since CCW is supplied at least while the power hold signal is being output, the transistor _TR7 is normally ON.

When signal CW is HIGH, turn TR ₇ off with TR ₉ to rotate motor M forward. Signal CW
Even after it becomes LOW, the motor continues to rotate due to inertia, so it will be operated beyond the specified amount driven by the motor. To prevent this, it is well known to quickly reduce the voltage across the motor to zero.

In the example shown in Figure 3, the problem was solved by adding a simple braking function to the bridge circuit that rotates the motor in the forward and reverse directions.

Conventionally, there has been a method of applying a signal in the reverse direction for a predetermined period of time after forward rotation to perform a braking operation using a bridge circuit, but it has been difficult to set this time appropriately. For example, if the reversal time is too long, the motor will reverse after stopping. Moreover, if the time is too short, the braking effect will be weakened.

In the specific example shown in Figure 3, TR ₇ is ON after the motor rotates forward, so motor (+) → TR ₇ collector → TR ₇ emitter → D ₂ anode → D ₂ cathode →
By configuring a closed group called motor (-) and quickly reducing the voltage across the motor to zero,
It has an effective electromagnetic brake function.

FIG. 5 shows another example of the motor drive circuit.

The signal CW makes TR ₆ ′ and TR ₈ ′ conductive, motor M′ rotates forward, and the signal CCW turns TR ₅ ′,
The third reason is that TR ₇ ' conducts and motor M' reverses.
This is the same as the example in the figure. In this example, the brake signal effectively applies the brake to stop both forward rotation and reverse rotation, and moreover, since no current flows through the transistor TR ₉ ' that normally constitutes the brake circuit except when the brake is applied, that is, Great power saving effect. I is an oscillation circuit, which generates the clock necessary for controlling the microcomputer.

H is a strobe trigger control circuit, which will be explained later.
When either SOL1 or SOL2 is ON, the ON of the mechanical synchro switch SSW is transmitted to the trigger input of the strobe circuit.

Before explaining the operation of the camera according to the present invention, the main switches installed in this camera will be explained.

Main switch MSW...The camera according to the present invention has one power supply, and this power supply supplies power to all of the control section, drive section, strobe circuit section, etc., and the main switch MSW uses this power supply. This is a switch that connects and disconnects the control section, drive section, strobe circuit section, etc. When this switch is opened, all electrical systems become inactive. This main switch is turned off when the slide cover that protects the lens and viewfinder is closed, and turned on when it is opened.

Reset switch RSW: This is a switch that resets the logic control unit, that is, the microcomputer, to its initial state.When the opening/closing lever (lever 10 in Fig. 1) that opens and closes the camera back is raised,
It is a switch that turns on and turns off when defeated.

1st release switch S ₁ ...This is a switch that turns on when the release button is pressed, and turns on when the release button is pressed lightly.

Second release switch...This is a switch that turns on when the release button is pressed.The difference from the first release switch _S1 is that it turns on when the release button is pressed deeply.

Knot switch NSW: This is an operating switch related to the notch provided on the outer periphery of the disk film for determining the frame position. It is a switch that turns OFF when the switch arm enters the notch and turns ON when it comes out of the notch. be.

Reverse switch GSW: Cameras that use disk film usually use a single drive source to advance the film, charge the shutter, and operate the shutter, and this is done using a mechanism that uses planetary gears.

In other words, the torque required for film advance and the torque used for shutter charge are such that when film advance is possible, the driving force of the motor is not transmitted to the shutter charge mechanism, and when film advance is locked, the driving force of the motor is not transmitted to the shutter charge mechanism. It is designed so that the motor's driving force is transmitted only to the shutter charge mechanism.

When the pawl that positions the photographic frame in a predetermined position enters the notch provided on the outer periphery of the disk film, making it impossible to advance the film, the cam wheel for shutter charge rotates, and when the pawl comes out of the notch, In this case, the cam wheel for shutter charge does not rotate and the film is advanced. The reverse switch GSW is a switch that is operated by a separate cam installed on this shutter charge cam wheel, and is turned on immediately after the pawl enters the notch and the cam wheel starts moving at the initial position, releasing the shutter (operation). This is a switch that turns OFF before the operation is performed.

Next, the operation of a specific example of the camera according to the present invention will be explained for each operation mode.

1 Shooting Preparation Mode The shooting preparation mode will be explained with reference mainly to FIG. 7, which is a time chart, and FIG. 6, which is a flowchart.

First, by raising the lever 10 for opening and closing the back cover, the reset switch RSW is turned on and the back cover opens simultaneously, making it possible to load the cartridge. Since the reset switch is turned on at this time, the camera will not operate even if the user operates the release switch or the like. When the cartridge is loaded and the back cover is closed, the opening/closing lever 10 collapses and the reset switch RSW turns OFF, thereby making the microcomputer MC ready for operation.

Next, by turning on the main switch MSW, the VB rise detection section of the microcomputer MC and power supply control circuit E is activated, the power supply voltage VDD rises, and this signal is used to generate a signal from the power hold terminal PH of the microcomputer MC. Power is held (PH,
ON-1).

Around the same time, microcomputers
A signal is output from terminal CW of MC, causing motor M to rotate forward. At this time, the motor rotation is performed by checking whether the notch switch is ON or OFF in the microcomputer MC (judgment NSW1) as shown in Figure 6, and if it is ON (motor forward rotation - 1). , continues until it is turned OFF, that is, until the notch claw enters the notch and the first frame of the film is fed to the predetermined position, and stops when it is fed to the predetermined position (motor stop-4). Note that the operating mode when the touch switch NSW does not operate will be explained later.

After the motor stops, the strobe is charged by a signal from the strobe charge signal terminal STP of the microcomputer MC after a predetermined time _△ t for restoring the power supply, and the charge completion signal is input to the microcomputer MC terminal END. Charging is performed. Charging will also stop if the charging completion signal is not output within the predetermined time set by timer T ₃ , and the power hold circuit will turn OFF after the time set by timer T ₇ (2.5 seconds) after charging is stopped. System hangs. In normal shooting preparation mode, the release button is not pressed, just by loading the film, opening the disk film slide cover, and setting it to standby, so at judgment S ₂ - 4, the second release switch S ₂ is turned OFF. After the time (2.5 seconds) determined and made by timer T ₄ , the power hold is
OFF and the entire system stops.

2 Normal Shooting Mode Normal shooting operation is naturally started by pressing the release button. That is, the first
Start by turning release switch S ₁ ON.

After that, the power supply voltage VDD rises, the power is held, and the notch switch is turned on at judgment NSW-1.
Determining whether NSW is ON or OFF, charging the flash with EF charging 1, and performing charging stop 2 are the same operations as in the shooting preparation mode described above. When the release button is pressed, the first release switch _S1 is activated, then the second release switch _S2 is activated.
Turn on. Therefore, the judgment S ₂ -4 in Figure 6
At , it is determined that _S2 is ON, and then at judgment ST it is checked whether the self-timer switch ST is ON or OFF.In the case of normal shooting, ST is OFF and the process moves to the photometry and distance measurement step.

This step will be explained with reference to FIG. 8b. After the second release switch S ₂ is turned on, until the power is stabilized, △t ₂ After that, the photometry data is read, that is, ED is read, and then the distance measurement timing signal FLD is output, and the distance measurement LED 1 emits light.
Reading of the distance measurement signal, that is, FD reading is performed. Both photometry data ED and distance measurement data FD indicate whether the subject is dark (EV12 or less) or bright.
This is a binary signal indicating whether the subject is far away (more than 1.2m) or close.

The camera in this specific example has an aperture of F2.8 and F8
A two-step control is performed, and the close-up lens is automatically inserted into the photographic lens system for close-up objects.

Specifically, the close-up lens is configured to move in and out of the optical system using a cam mechanism every time the shutter is charged, and at close range, the magnet SOL2 is activated to hold the close-up lens in the photographic optical system. Since the magnet SOL2 is inactive when shooting at long distances, a mechanism is adopted in which the close-up lens is retracted outside the photographic optical system.

SOL1 is a magnet for aperture control, and this is
Set the aperture to F2.8 when ON, and F8 when OFF. Furthermore, strobe light emission control is also performed automatically. SOL2 is a magnet that controls the close-up lens, and its mechanism is as described above.

Control of the aperture, strobe light emission, and close-up lens is processed by the logic shown in FIG. 14. In other words, when the subject is close, SOL1 is OFF and the aperture is set to F8, i.e.
The aperture is set to a small aperture, SON2 is turned on, the close-up lens is held within the photographic optical system, and it is controlled so that a strobe trigger signal is output.

If the subject is far away and bright,
When SOL1 is OFF, the aperture is set to F8 (small aperture), and when SOL2 is also OFF, the close-up lens is outside the photographic optical system during exposure, and is controlled so that no strobe trigger signal is output.

If the subject is far away and it is dark, use SOL1.
When ON, the aperture is set to F2.8, that is, wide open.
When SOL2 is OFF, the close-up lens is located outside the optical system and is controlled to output a strobe trigger signal, as described above. What is unique about this process is that when the subject is close, the aperture is set to a small aperture (for example, F8) and the strobe is fired, regardless of the brightness or darkness of the subject. This is because in close-up photography, in most cases the subject is not extremely bright, apart from the background, and close-up photography is often done indoors or in similar conditions, so a small aperture is used to capture the depth of field. This process is based on statistical results, showing that better photos can be obtained by increasing the depth of the lens and firing the strobe.

In particular, the above processing is effective in a system like this camera in which the aperture and lens are controlled in only two stages each. Note that this processing method is also effective when controlling the aperture and the lens in about three or four stages, respectively.

The routine between distance measurement and normal rotation of the motor 3 in FIG. 6 is a step for setting the above-mentioned photographing conditions.

To make sure that the close-up lens is working properly when shooting at close range,
LED2 lights up and displays the time from when SOL2 turns ON until the next time the motor starts operating.

Figure 3 shows the self-timer operation display, which will be described later.
LED2 is shared with the above display. That is,
Self-timer LED signal SLD and SOL2 signal
Driver DR ₁ when either FMG outputs
is configured to operate.

Also displayed when motor M is operating.
The power supply voltage of LED2 may fluctuate and the LED may flicker, so when the motor forward rotation signal CW is output, driver _DR2 is activated and the display is
LED2 is turned off.

Next, the motor rotates forward 3. In this case, the claw is inserted into the notch in the film, so the film does not rotate, and the motor rotates to charge the shutter. According to the conditions of SOL1 and SOL2, the aperture and close-up lens are set, and then the shutter is operated. and the film is exposed. In addition, in synchronization with the shutter being fully opened, the synchro switch SSW is turned on, and in the case of strobe photography, a trigger signal is output and the strobe fires.

After the film is exposed, the motor continues to rotate forward, rotating the cam wheel, and the claw is removed from the notch. The operation of this pawl is also performed by another cam provided on the above-mentioned shutter charge and shutter operation cam wheel. Almost at the same time as this claw is removed from the notch, the notch switch NSW turns on.
The SOL1 and SOL2 are turned off (SOL, OFF),
Cancels the shooting conditions that were set. When the pawl is removed from the notch, the cam wheel stops rotating, the rotational force of the motor is transmitted to the film, the film rotates, and the pawl rotates until it enters the next notch, and when the notch enters the next pawl, the notch switch NSW
The motor stops with the OFF signal. After the motor stops, strobe charging (EF charging-2) is performed again.
Charge for the next photo is charged to the strobe power supply capacitor. When the charging completion signal END is output, strobe charging ends, power hold is turned off, power supply voltage VDD becomes LOW, and the entire system stops.

In addition, in the above operation, the reverse switch GSW is momentarily turned ON by the cam installed on the shutter operating cam wheel just before the shutter is charged, but this is for activation after the final frame has been photographed, which will be explained later. This is ignored in this normal shooting mode. That is, judgment GSW3 in Figure 6
In judgment NSW2, Notsuchi Switch NSW
is ON and the reverse switch GSW is ON, the routine enters and another mode of operation begins, but as shown in Figure 5, in this operation mode,
Since there is no point in time when NSW and GSW are ON at the same time, NSW3 proceeds to motor stop 7 and the above operation is performed.

This camera is designed for single and continuous shooting. Prior to shooting, the photographer can select the above-mentioned single shooting mode or continuous shooting mode using a changeover switch. After EF charging 2nd,
Judgment S/C is performed to see whether it is single shooting or continuous shooting, and in the case of single shooting, the route indicated by OFF is followed and power hold OFF (PH, OFF3) is performed. In the case of continuous shooting, proceed to the route indicated by ON and judge S ₂ −
2 to check whether the second release switch S ₂ is ON or OFF, and if it is OFF, the power hold will be OFF.
If it is ON, the process returns to judgment ST, and a series of photographic operations such as photometry, distance measurement, and shutter operation are performed again.

3 Self-timer Photography Mode In the camera according to the present invention, the self-timer photography operation is performed independently of the release button. That is, by simply pressing the self-timer button, the self-timer operation and subsequent photographing operation are performed without pressing the release button. When you press the self-timer button, the self-timer switch ST turns on.

When ST is turned on, the power supply VDD rises, power hold PH, ON strobe charging, and strobe charging is stopped, which are the same operations as explained in the normal shooting mode.

Self-timer switch ST, first release switch _S1 and second release switch _S2 are the first
It consists of the circuit shown in Figure 5.

In other words, when the self-timer switch ST is turned on, the terminal that enters the microcomputer MC
Not only ST, but also input terminal _S2 and switching element _TR1 are turned on at the same time. Therefore, in judgment S ₂ -4 after strobe charging is stopped, S ₂ is also ON.
It is determined that this is the case, and the process proceeds to judgment ST. Next, an LED display indicating that self-timer photography is being performed is performed by lighting up LED 2, and a determination is made as to whether 10 seconds have elapsed. After 10 seconds, the same operation as in normal shooting mode will be performed. Until now, there have been cameras that operate the self-timer independently of the release button, just like this camera, in other words, the shutter automatically turns off after a predetermined amount of time by simply pressing the self-timer button. It is being An example is Konica FS-1 (manufactured by Konishiroku Photo Industry Co., Ltd.).

However, in the past, the self-timer release switch was mechanically activated by turning on S ₁ , S ₂ , and ST.
The switch structure was complicated because it was configured to do so. According to the circuit shown in FIG. 15, a simple and inexpensive switch such as a conductive rubber switch used in calculators and the like is sufficient.

As shown in FIG. 6, photometry, distance measurement, and based on this, setting of the aperture and focusing of the optical system are performed at the end of the self-timer operation. Therefore, for example, even if the subject moves and the distance to the subject changes during the self-timer operation, an in-focus photograph can be obtained.

4. Self-timer cancellation mode In the camera according to the present invention, after setting the self-timer, it is possible to cancel the setting while the self-timer is in operation. FIG. 10 shows a time chart of this self-termer release mode.

After turning on the self-timer ST and starting its operation, press the self-timer button again and turn on the switch ST. It is determined that the ST has been released in the judgment in Figure 6, and the predetermined time created by the timer _T7 (2.5 seconds)
Afterwards, the power hold PH turns OFF and the entire system stops.

5 Final photographing mode The procedure from step _S1 to SOL OFF in Fig. 6 is the same as in the normal photographing mode.

The motor rotates to advance the film after the shutter is activated, but after the final frame has been taken, the disk film system cannot advance the film after a short distance, so the film stops with the notch claw sticking out of the film notch. I will do it. Therefore, the switch
NSW will continue to be in the ON state as shown in Figure 11. Therefore, judgment NSW2 is ON
It is determined that this is the case, and in this state, the shutter charge and cam wheels will continue to rotate.
The cam wheel returns to its initial position and tries to continue rotating, but at this time the reverse switch GSW
is turned ON, it is determined that judgment GSW-3 is ON, and the process proceeds to motor stop 1 and motor reverse rotation. Then, the motor reverses until the reverse switch GSW reverses the cam wheel, turning it off again, and then stops. After the motor stops, the power hold turns OFF and the entire system stops.

If you do not reverse the rotation after taking the final frame, the motor will continue to rotate because the notch switch NSW will remain ON, but the film will not rotate any further due to the structure of the cartridge, so the rotation of the motor will be transmitted to the cam wheel. It turns out. The cam wheel rotates once, starts charging the shutter again from the initial position, and then releases the shutter.
Repeat this until the motor stops,
The film becomes a multiple exposure. To prevent this, after the final frame has been photographed, before the cam wheel performs shutter charge again, the cam wheel is reversed, returned to its initial position, and then the motor is stopped.

Furthermore, FIG. 12 shows an operation for prohibiting photographing in the above-described state.

6 Shooting Prohibition Mode After Shooting the Last Frame It is quite possible that the user may accidentally press the release button even after shooting the final frame. FIG. 12 is a time chart of the operation in such a case. As shown in FIG. 11, the notch switch NSW remains in the ON state after the final frame has been photographed.

When the first release switch S ₁ is turned ON in this state, it is determined that the notch switch NSW is ON at determination NSW-2 after power hold.
Then the motor rotates forward. The cam wheel is rotated by the forward rotation of the motor, and the reverse rotation switch GSW is activated.
Turn it on. Therefore, the motor is reversed in the same way as in the final frame shooting mode, and when the reverse switch GSW is turned OFF, the motor is stopped (motor stop-2), the time elapsed power hold by timer 7 is turned OFF, and the entire system is turned off. Stop.

7 Aerial shooting mode Even if there is no film in the camera,
The user may press the release button by mistake. FIG. 13 is a time chart showing the operation of the camera in such a case.

First, the first release switch turns ON (S ₁ ON) and starts operation, but from this step, EF charging, charging stop, photometry, distance measurement, and motor forward rotation -3 are performed in normal shooting mode. is the same as

As already explained, the notch switch NSG is turned OFF when the claw is in the notch of the film, and turned ON when the claw is removed from the film notch and rests on the film.

When there is no film in the camera, the claw is in a free state, the same state as when the film is in the notch. Therefore, when there is no film in the camera, the
NSW is in OFF state.

Therefore, in the judgment NSW-2, NSW is OFF.
After the time determined and made by timer T ₅ ,
The motor stops (motor stop - 5), and after the time set by timer _T7 has elapsed, the power hold turns OFF and the entire system stops. The motor sound at this time allows the user to know that no film is loaded.

In the operation of the camera of the present invention explained above,
One of the distinctive points is that at the end of each operation, the power hold continues for a predetermined time (2.5 seconds) after the completion of the element operation, and after this time, the power hold is released and the entire system stops. This is the point. (Fig. 7, Fig. 10, Fig. 11, Fig. 12,
(See abort timer C in FIG. 13 and timer T ₇ in FIG. 6).

This prevents external signals from being input to the microcomputer MC during this time, and if the photographer makes an incorrect operation, the camera will continue to perform unnecessary operations without delay, and the resulting battery consumption will be reduced. This is to prevent this.

A supplementary explanation will be given regarding the EF charging surrounded by the dashed line in Fig. 6. After charging the EF, if no charging signal is output from the strobe circuit after the time set by timer _T3 has elapsed, charging is stopped (charging stop - 1) and the entire operation is stopped.

Then, after waiting for the battery to recover, the first
The battery can be used effectively by accepting the release switch S ₁ again and recharging it.

The automatic camera equipped with the strobe device of the present invention has been described above. These various operations are controlled by a microcomputer, and the microcomputer has a minimum operating voltage that guarantees operation. In the past, during strobe charging, the minimum operating voltage could drop even for a short period of time, and this could disrupt a wide range of camera operations. The present invention has been made by clarifying this cause. With the present invention, camera malfunctions are completely eliminated, and unlike conventional strobe charging, which takes a long time to prevent voltage drop, the charging time is shortened. The strobe was charged in a short amount of time, and it became possible to always take good pictures, including strobe photography.

[Brief explanation of drawings]

Fig. 1 is a front view of a specific example of the camera of the present invention, Fig. 2 is a block diagram of the control and drive section of the same example, Fig. 3 is its circuit diagram, and Fig. 4 is a specific example of the camera shown in Fig. 3. Figure 5 showing an example of strobe charging mode in the example.
The figure shows an example of a drive circuit for a motor that performs film advance, shutter charge, and shutter operation. Fig. 6 is a flow diagram showing the operation of the camera shown in Figs. A time chart showing the operation of the camera shown in Figs. 3 and 6 in the shooting preparation mode, Fig. 8 a time chart showing the operation in the normal shooting mode, and Fig. 9 showing the operation in the self-timer shooting mode. Time chart. Figure 10 is a time chart showing the operation in the self-timer release mode. Figure 11 is a time chart showing the operation in the final frame shooting mode. Figure 12 is the operation when the release button is pressed after the final frame shooting is completed. Fig. 13 is a time chart showing the operation in sky photography mode, Fig. 14 is a logic diagram showing the setting conditions of the aperture, photographing optical system, and strobe based on photometry and distance measurement data, Fig. 15 The figure is a circuit diagram showing the mutual connection relationship of a first release switch, a second release switch, and a self-timer switch. A...Logic control circuit, B...Distance measuring circuit, C...
Photometering circuit, F... Strobe circuit, SOL1... Aperture control magnet, SOL2... Close-up lens control magnet, H... Trigger control circuit.

Claims (1)

[Claims] 1. In a camera strobe device that shares a power source with a microcomputer that controls multiple functions of the camera, a charging circuit that charges the strobe; a first voltage level of the power source that allows the microcomputer to operate; a power supply voltage detection circuit that detects a second voltage level that is higher than the first voltage level; Stop strobe charging,
A strobe device for a camera, comprising: a charging control circuit that starts charging the strobe when the power supply voltage detection circuit detects that the voltage level has returned to the second voltage level.