JP2002372741A - Stroboscopic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that a user can confirm the charging of a stroboscopic device by whining sound to be sounded by it's own body of a transformer in the stroboscopic device in which a wire wound transformer is adopted, however, when a piezoelectric transformer is adopted in the device instead of the wire wound transfer, the user can not confirm the charging of the device by sound. SOLUTION: This stroboscopic device is provided with at least a flashing discharge tube, a charge and discharge capacitor storing energy for making the flashing discharge tube emit light, a piezoelectric transformer as a boosting means for charging energy on the charge and discharge capacitor, a driving circuit driving the piezoelectric transformer and a voltage controlled oscillation circuit generating an oscillation signal to be supplied to the driving circuit and, moreover, the device is provided with a charged voltage detecting means detecting the charged voltage of the charge and discharge capacitor and a sound generating means rumbling in accordance with the oscillation signal and the device informs the user of the charged state of the capacitor by changing the rumbling state of the sound generating means in accordance with the change of the oscillating state of the oscillation signal by the voltage control oscillation circuit according to the detected results of the charged voltage detecting means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a strobe device using a piezoelectric transformer. More specifically, the present invention relates to a notifying means for notifying a charge state of a charge / discharge capacitor that stores energy for causing a flash discharge tube to emit light in a flash device.

[0002]

2. Description of the Related Art Conventionally, cameras for taking silver halide photographs,
Alternatively, as a digital camera that captures an image using an image sensor, a so-called strobe device that instantaneously illuminates a subject at the time of photographing has become widespread.

The above-described strobe device generally includes a charging circuit for boosting the power supply voltage and charging the charge / discharge capacitor with the light-emitting energy of the discharge tube, and a trigger circuit for promoting (starting) light emission. For example, JP-A-200
As disclosed in Japanese Patent Application No. 0-241860, a winding transformer is employed for each of the charging circuit and the trigger circuit.

When charging the charging / discharging capacitor with energy for light emission, the frequency of the winding transformer changes as charging progresses, and the beat of the winding transformer itself is heard as a sound. Completion can be confirmed by the change in sound, and you are used to it.

[0005] However, in recent years, there has been a demand for miniaturization and weight reduction of the camera device itself. However, in the above-mentioned strobe device, the weight and size of the winding transformer are problematic, and thus the demand for miniaturization and weight reduction is met. It is difficult. Therefore, Japanese Patent Application Laid-Open
No. 00-321634 proposes a strobe device employing a piezoelectric transformer instead of a winding transformer.

The use of a piezoelectric transformer in place of a winding transformer can meet the demand for a smaller and lighter camera. However, a piezoelectric transformer generates its own beat sound like a winding transformer. Since it does not occur, the user cannot confirm the completion of charging as it is. In addition, it is possible to assist charging confirmation by turning on a lamp like a monitor, but in this case, it is different from the confirmation method using sound that the user has been accustomed to for many years. Absent.

[0007]

As described above, the user can confirm the charging of the strobe device by the beat sound generated by the winding transformer itself. However, when a piezoelectric transformer is used instead of the winding transformer, , Sound cannot confirm the charge.

[0008]

The present invention provides the following means for solving the above-mentioned problems. Specifically, at least a flash discharge tube, a charge / discharge capacitor for storing energy for causing the flash discharge tube to emit light, a piezoelectric transformer as a boosting unit for charging the charge / discharge capacitor with energy, A strobe device including a drive circuit for driving a transformer, and a voltage-controlled oscillation circuit for generating an oscillation signal to be supplied to the drive circuit,
Charge voltage detection means for detecting a charge voltage of the charge / discharge capacitor; and sound generation means for sounding in response to the oscillation signal, wherein the voltage control oscillation circuit oscillates the oscillation signal in accordance with a detection result of the charge voltage detection means. The charging state of the charging / discharging capacitor is notified by changing the sounding state of the sounding means in accordance with the state change.

Here, the voltage control oscillation circuit generates a burst oscillation signal in response to the charging voltage detecting means detecting the full charge of the charging / discharging capacitor, so that the oscillation signal is charged / discharged. It is characterized in that it is changed so as to be different from the state during charging of the capacitor. Further, the sounding means is a piezoelectric sounding body.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of a charge state notifying circuit in a flash device according to the present invention.

FIG. 1 is a block diagram of a charging state notification circuit in a flash device according to the present invention. The charge state notification circuit shown in FIG. 1 includes a booster circuit 10 including a drive circuit 103 and a piezoelectric transformer (for example, a Rosen type piezoelectric transformer) 104, a power supply 101, a voltage controlled oscillator circuit 102, a rectifier circuit 105, a charge voltage detection circuit. 106, a trigger signal generating circuit 107 for promoting discharge of the discharge tube 109, a charge / discharge capacitor 1 for storing electric energy for causing the discharge tube 109 to emit light
08, a flash discharge tube (for example, a xenon discharge tube) 109, and a sound generator 110.

Here, the drive circuit 103 includes, for example, FIG.
As shown in (1), if a general circuit using a bridge circuit including two switching elements (field-effect transistors 501 and 502) and an inductor 503 that converts a rectangular wave output from the bridge circuit into a sine wave is adopted. good. Further, a rectifier diode may be used for the rectifier circuit 105.

In FIG. 1, since a general device may be employed at present for the circuit configuration such as a drive circuit, a trigger circuit, and a rectifier circuit, a detailed description of this embodiment will be omitted.

The charge voltage detection circuit 106 is composed of, for example, voltage dividing resistors 601 and 602 for dividing the potential Vc of the charge / discharge capacitor and an error amplifier circuit 603 as shown in FIG. The error amplification circuit 603 compares the input voltage Vri from the voltage-dividing resistor with the reference voltage Vref, and only when Vri becomes larger than Vref, the output Vctr becomes HIGH.

The output of the charging voltage detection circuit 106 is input to the voltage controlled oscillation circuit 102. Voltage controlled oscillation circuit 10
2 includes a first oscillator 401, a second oscillator 402, a duty ratio setting circuit 403, and an AND element 404, as shown in FIG.

Here, the first oscillator 401 has a predetermined first
The second oscillator 402 outputs a signal having an oscillation frequency (a first oscillation signal), and the second oscillator 402 outputs a second oscillation signal having a frequency lower than the first oscillation frequency output from the first oscillator 401.

Further, the duty ratio setting circuit 403
The duty ratio is set to the second oscillator 402 according to the input signal Vctr from the charging voltage detection circuit. The resulting output of the first oscillator 401 and the second oscillator 402
Is ANDed by the AND element 404 and output to the drive circuit 103 and the sound generator 110.

There are two types of duty ratios set by the duty ratio setting circuit 403 to distinguish between charging and charging completion, one of which is 100%.
The balance may be, for example, 50%.

When the duty ratio is 100%, the signal output from the second oscillator is a DC signal. Therefore, the drive signal output from the oscillation circuit 102 is output from the first oscillator as shown in FIG. Output signal itself. On the other hand, if the duty ratio is set to 50%, the drive signal output from the oscillation circuit 102 becomes an intermittent signal as shown in FIG. 2B.

The switching of the duty ratio is performed according to the input signal Vctr from the charging voltage detection circuit 106.
When Vctr is LOW, the duty ratio is set to 100%, and the first oscillation signal is output as a drive signal.
On the other hand, when Vctr is HIGH, the duty ratio is set to, for example, 50%, and a signal generated by taking the logical product of the first oscillation signal and the second oscillation signal is output as the oscillation signal.

The output signal of the oscillation circuit 102 is
Also given to 0. As the sounding body 110, for example, a piezoelectric buzzer can be used. The piezoelectric buzzer is an AC piezoelectric buzzer that emits a sound according to the frequency when an AC signal is given,
There is a DC piezoelectric buzzer that emits at a specific frequency when a DC signal is applied.

Accordingly, the AC piezoelectric buzzer can be sounded by directly applying the AC signal from the oscillation circuit 102, or the DC piezoelectric buzzer can be sounded by converting the AC signal from the oscillation circuit 102 into DC.

In the case of this embodiment, if the first oscillation signal is, for example, a signal having a frequency of 100 kHz, even if this signal is directly input to the sounding body 110, it cannot be heard by human ears. Therefore, at the time of charging, substantially no sound is output from the buzzer. On the other hand, when charging is completed, the signal input to the sounding body 110 is, for example, 100 Hz as shown in FIG.
If it is an intermittent signal, a 100 Hz sound is heard. The reason why the oscillation signal frequency is set to 100 kHz or 100 Hz is merely an example, and naturally changes by changing the type of the piezoelectric transformer and the setting of the duty ratio.

When the output signal of the oscillation circuit 102 is converted into a DC signal through a filter circuit, a signal as shown in FIG. 3 is obtained. This filter circuit may adopt, for example, a general circuit configuration including a capacitor (C) and a resistor (R). In this case, the filter circuit can be provided between the oscillation circuit 102 and the sounding body 110. FIG. 3A
FIG. 3B shows the converted first oscillation signal during charging.
Is obtained by converting the oscillation signal corresponding to FIG. 2B when charging is completed. In the DC piezoelectric buzzer, the input signal is HIGH
When these signals are input to the DC piezoelectric buzzer, in the case of an input signal as shown in FIG. 3A, a continuous sound is output from the buzzer, and an intermittent signal as shown in FIG. 3B is obtained. Is input, an intermittent sound is output from the buzzer.

When a low-pass filter circuit is used as a filter circuit and input to an AC piezoelectric buzzer,
At the time of charging, a silent state is set, and at the time of completion of charging, a sound having a frequency of, for example, 100 Hz is generated in the above case.

[0026]

As described above, according to the present invention, the charging state of the flash device can be easily grasped by sound even with the flash circuit using the piezoelectric transformer as the boosting means. As a result, the user can perform strobe shooting without feeling strange.

[Brief description of the drawings]

FIG. 1 is a block diagram of a flash device according to an embodiment of the present invention.

FIG. 2 is a diagram showing an oscillation signal output from a voltage controlled oscillation circuit 102 according to the embodiment of the present invention.

FIG. 3 is a diagram showing an input signal to a sounding body 110 in the embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration of a voltage controlled oscillation circuit 102 in FIG.

FIG. 5 is a block diagram showing a configuration of a driving circuit 103 in FIG.

FIG. 6 is a block diagram showing a configuration of a charging voltage detection circuit 106 in FIG.

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Claims (3)

[Claims] At least a flash discharge tube, a charge / discharge capacitor for storing energy for causing the flash discharge tube to emit light, a piezoelectric transformer as boosting means for charging the charge / discharge capacitor with energy, A strobe device comprising: a drive circuit for driving a transformer; and a voltage control oscillation circuit for generating an oscillation signal to be input to the drive circuit, wherein the charge voltage detection means detects a charge voltage of the charge / discharge capacitor; Sounding means for sounding in response to a signal, wherein the sounding state of the sounding means changes as the voltage controlled oscillation circuit changes the oscillation state of the oscillation signal according to the detection result of the charging voltage detecting means. By
A strobe device for notifying a charge status of the charge / discharge capacitor. 2. The charge-discharge capacitor according to claim 2, wherein the charge-voltage detection means detects a full charge of the charge-discharge capacitor, and the voltage-controlled oscillation circuit generates a burst oscillation signal. The strobe device according to claim 1, wherein the strobe device is changed to be different from a state during charging. 3. The strobe device according to claim 1, wherein the sounding means is a piezoelectric sounding body.