JP2003005260A - Stroboscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stroboscope excellent in space saving with a simple and low cost device configuration. SOLUTION: In the stroboscope sharing a set of booster circuits (11, 12, 13) for charging a discharge capacitor 3 and triggering a discharge tube 4, the anode terminals of the discharge capacitor 3, the discharge tube 4, and a rectifier diode 16 are connected in parallel, respectively, and when a switch 20 is closed, they are grounded to the reference potential (ground voltage). When the switch 20 is changed over from the close state to the open state by a trigger control circuit 19, the discharge capacitor 3 and the discharge tube 4 are brought into floating state cut off from the ground potential, and in this state, high voltage capable of being a trigger signal to stimulate flashing of the discharge tube 4 is applied to a trigger line 25 connected with the trigger terminal of the discharge tube 4, and the discharge tube 4 flashes by the electric energy charged in the discharge capacitor 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a strobe device, for example, to a strobe device suitable for being built in or externally attached to various cameras.

[0002]

2. Description of the Related Art Conventionally, a camera for taking a silver halide photograph,
Alternatively, a so-called strobe device that instantaneously illuminates a subject at the time of shooting is prevalent in a digital camera that captures an image using an image sensor.

As an example of such a strobe device, the applicant of the present application has proposed a compact and lightweight strobe device with a simple device configuration in the prior Japanese Patent Application No. 2000-395929 (which has not been published at the time of filing of the present application). In order to realize it, the strobe device shown in FIG. 3 is proposed.

That is, the strobe device shown in FIG. 3 is roughly classified into a discharge tube for flashing (for example, a xenon discharge tube) 4, a discharge capacitor 3 for storing electric energy for causing the discharge tube 4 to emit light, and an electric energy for the discharge capacitor 3. It is composed of a charging circuit 1 for charging and a trigger circuit 2 for generating a high voltage signal that prompts the discharge tube 4 to discharge.

The circuit is a charging circuit 1 and a trigger circuit 2.
The step-up circuit (11, 12, 13) including one piezoelectric transformer 13, which is commonly used as the step-up means of the piezoelectric transformer 13, is provided in the step-up circuit. The secondary electrodes 6 are respectively provided at two different distances (L1, L2) from the primary electrode 5 provided in the area.
7 is provided, and the switch 14B connected to the charging line in the secondary side region of the piezoelectric transformer 13 and the switch 14C connected to the trigger line are appropriately turned on / off to charge the discharge capacitor 3. The operation and the trigger operation of the discharge tube 4 are realized.

[0006]

According to the above circuit configuration, in the piezoelectric transformer 13 provided in one booster circuit, the two secondary electrodes thereof are used for the charging circuit and the trigger circuit. It is possible to achieve both the charging function and the trigger function with only one booster circuit, and it is possible to realize a strobe device having a simple device configuration and excellent space saving.

However, in the above circuit configuration, the switch 14 connected to the secondary electrodes 6 and 7 of the piezoelectric transformer 13
B and the switch 14C have an AC high voltage (several k) output from the piezoelectric transformer 13 according to the switching operation.
Since a voltage of about V) is applied, it is necessary to use a high withstand voltage switching element that can withstand the high AC voltage.

However, the high breakdown voltage switching element that can be employed at the time of filing the present application to turn on / off the output voltage of the piezoelectric transformer, such as the switch 14B and the switch 14C, is expensive and has a relatively large external size. The circuit configuration shown in FIG. 3 is not sufficient to meet the demand for further downsizing of the strobe device, which becomes a factor that prevents downsizing of the overall shape of the strobe device.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a strobe device which has a simple and low-cost device configuration and is more space-saving.

[0010]

In order to achieve the above object, the strobe device according to the present invention is characterized by the following configurations.

That is, a discharge tube (4) for flash light and a capacitor (3) for storing electric energy for causing the discharge tube to emit light.
And a charging circuit (11, 12, 13A, 15, 16, 18) for charging the capacitor with electric energy, and a trigger circuit (1 for generating a high voltage signal for urging the discharge tube to discharge.
1, 12, 13A, 19, 19A, 25) and a booster circuit (11, 12,
13A), a switch device or the like for disconnecting the capacitor and the discharge tube from a reference potential (ground potential) common to the charging circuit and the trigger circuit according to the operation of the trigger circuit. The switching means (20) is provided.

According to this device configuration, the charging circuit and the trigger circuit are in a floating state separated from the common reference potential in accordance with the operation of the trigger circuit, so that the withstand voltage characteristic required for the switching means is A few hundred volts is sufficient. Therefore, the switch 14 described above with reference to FIG.
Unlike the switch B and the switch 14C, a high AC voltage of about several kV is not applied between both ends of the switch, and a low cost and small member (switch element) can be adopted as the switching means. That is, it is possible to provide a strobe device that has a simple and low-cost device configuration and is more space-saving.

In a preferred embodiment, there is further provided a second switching means (21) for disconnecting at least the capacitor and the discharge tube from the secondary side electrode of the piezoelectric transformer according to the operation of the trigger circuit. The capacitor and the discharge tube form a closed circuit in a state where they are separated from the reference potential and the secondary side electrode of the piezoelectric transformer.

Any strobe device having any of the above configurations is suitable for use in a camera built in or externally attached to various cameras. In that case, the trigger circuit is
It may be operated according to the shutter operation of the camera.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a flash device according to the present invention will be described in detail below with reference to the drawings.

[First Embodiment] FIG. 1 is a block diagram showing the circuit arrangement of a strobe device according to the first embodiment.

The strobe device shown in FIG. 1 is roughly classified into a discharge tube for flashing (for example, a xenon discharge tube) 4, a discharge capacitor 3 for storing electric energy for causing the discharge tube 4 to emit light, and a discharge capacitor 3 for charging the electric energy. It is composed of a charging circuit and a trigger circuit for generating a high voltage signal for urging the discharge tube 4 to discharge.

The charging circuit and the trigger circuit are the oscillation circuit 1
1, a drive circuit 12, and a pair of booster circuits including a piezoelectric transformer 13A are provided as common booster means, and the drive circuit 12 responds to an oscillation signal of a predetermined frequency output from the oscillator circuit 11 by the piezoelectric transformer. Drive 13A.
Here, the piezoelectric transformer 13A is a Rosen type piezoelectric transformer element.

As for the individual circuit configurations of the oscillation circuit 11 and the drive circuit 12, a general device may be adopted at present, and therefore detailed description of this embodiment will be omitted.

As shown in FIG. 1, the discharge capacitor 3, the discharge tube 4, and the anode terminal of the rectifying diode 16 are connected in parallel, and when the switch (switch element) 20 is in the closed state, the reference potential. Ground to (ground voltage).

Here, the switch (switch element) 20 includes a transistor F having a withstand voltage characteristic of about several hundreds of volts.
Semiconductor elements such as ET (field effect transistor) and IGBT (insulated gate bipolar transistor) can be adopted, and the operation state (closed state / open state) is switched by the trigger control circuit 19.

In the present embodiment, the charging circuit is composed of the oscillation circuit 11, the driving circuit 12, the piezoelectric transformer 13A, the rectifying circuit 18, the discharging capacitor 3 and the switch 20. When the switch 20 is closed, the piezoelectric transformer is closed. The output voltage of 13A is rectified by a rectifier circuit 18 having a general configuration including two diodes 15 and 16, and then charged in the discharge capacitor 3 as electric energy for discharging the discharge tube 4.

On the other hand, the trigger circuit includes an oscillation circuit 11, a drive circuit 12, a piezoelectric transformer 13A, a trigger control circuit 19,
It is composed of the discharge tube 4, the switch 20, and the trigger line 25, and the discharge capacitor 3 and the discharge tube 4 are separated from the ground potential in response to the switch 20 being switched from the closed state to the open state. Becomes

In the floating state, the load connected to the secondary electrode of the piezoelectric transformer 13A has a high impedance state as compared with the case where the switch 20 is in the closed state. In response to the change in the boosting ratio of the piezoelectric transformer 13A, the trigger line 2 connected to the trigger terminal of the discharge tube 4
A high voltage that can serve as a trigger signal for prompting a flash of the discharge tube 4 is applied to the discharge tube 5, and the discharge tube 4 emits a flash of light by the high voltage as a trigger due to the electric energy charged in the discharge capacitor 3.

Further, in this embodiment, the switch 20
The trigger control circuit 19 for controlling the operation state of No. 1 operates according to a trigger start signal input from the outside, and in a preferred embodiment, the strobe device according to the present embodiment is built in or externally attached to various cameras. When it is used as a strobe device for a camera, the trigger control circuit 19 (switch 2
0) should be operated.

According to the above-described embodiment, the discharge capacitor 3 and the discharge tube 4 are in a floating state separated from the common reference potential (ground potential) by the switch 20 according to the operation of the trigger circuit. The withstand voltage characteristic required for the switch 20 is about several hundreds V. Therefore, like the switches 14B and 14C described above with reference to FIG. 3, several kV is across the switches.
High AC voltage is not applied to the switch 2
As 0, a low cost and small member (switch element) can be adopted. That is, it is possible to provide a strobe device that has a simple and low-cost device configuration and is more space-saving.

[Second Embodiment] Next, a second embodiment based on the strobe device according to the above-described first embodiment will be described. In the following description, a duplicate description of the same configuration as that of the first embodiment will be omitted, and the description will focus on the characteristic part of the present embodiment.

In the above-described first embodiment (FIG. 1), the discharge tube 4 is triggered by the switch 20 which disconnects the discharge capacitor 3 and the discharge tube 4 from the ground potential. Therefore, when the switching element used as the switch 20 and the entire control circuit do not match well,
When the switch 20 is opened, the trigger line 2
It is also conceivable that the light emission of the discharge tube 4 cannot be triggered because the voltage (trigger signal) applied to 5 does not reach a predetermined high voltage necessary and sufficient to promote the light emission of the discharge tube 4. Therefore, in the present embodiment, it is a further object to make the discharge tube 4 emit light more reliably, based on the strobe device according to the first embodiment.

FIG. 2 is a block diagram showing the circuit configuration of the strobe device according to the second embodiment.

The circuit configuration of the strobe device shown in FIG. 2 is further different from that of the strobe device described with reference to FIG. 1 in that the secondary side electrode of the piezoelectric transformer 13A and the input stage of the rectification circuit 18 are further added. A switch (switch element) 21 connected in series is provided between and.

In the present embodiment, the switch (switch element) 21 may be a semiconductor element such as a transistor, an FET, an IGBT, etc., like the switch 20, and the trigger control circuit 19A allows the operation state (closed state / closed state). The open state) can be switched.

Also in this embodiment, the switch 2
Trigger control circuit 19A for controlling the operating states of 0 and 21
Operates in accordance with a trigger start signal input from the outside, and in a preferred embodiment, when the strobe device according to the present embodiment is adopted as a strobe device for a camera built in or attached to various cameras, , The trigger control circuit 19A according to the shutter operation of the camera.
(Switches 20 and 21) should be operated.

More specifically, the trigger control circuit 19A is
When the charging of the discharge capacitor 3 is started, the switches 20 and 21 both of which are in the open state are first switched to the switch 2
First, the switch 20 is switched to the closed state in this order.
Then, when the discharge tube 4 is triggered, the trigger control circuit 19A switches the switches 20 and 21 that are both in the closed state to the open state in the order of the switch 20 and then the switch 21.

According to the above-described embodiment, the discharge capacitor 3 and the discharge tube 4 are separated from the common reference potential (ground potential) by the switch 20 according to the operation of the trigger circuit, and the discharge capacitor 3 is in a floating state. The switch 3 and the discharge tube 4 are also separated from the secondary side electrode of the piezoelectric transformer 13A.

That is, the discharge capacitor 3 and the discharge tube 4 are
A closed circuit is formed, and the piezoelectric transformer 13A
The influence of the stray capacitance of the circuit connected to the secondary side is eliminated, and a higher impedance state can be realized in the secondary electrode of the piezoelectric transformer 13A as compared with the first embodiment. A predetermined high voltage necessary and sufficient for promoting the light emission of the tube 4 can be applied to the trigger line 25, and as a result, the discharge tube 4 can more reliably emit light.

As described above, according to this embodiment, in addition to the same effect as that of the first embodiment, the discharge tube 4 can be made to emit light more reliably.

In the present embodiment, the switch 21
Was connected in series to the secondary side electrode of the piezoelectric transformer 13A, but is not limited to this circuit configuration, and similarly to the switch 14C in the circuit shown in FIG. The switch and the switch 21 may be interlocked (in this case, when one is in the open state, the other is in the closed state).

[0038]

According to the present invention described above, it is possible to provide a strobe device having a simple and low-cost device configuration and being more space-saving.

[Brief description of drawings]

FIG. 1 is a block diagram showing a circuit configuration of a strobe device according to a first embodiment.

FIG. 2 is a block diagram showing a circuit configuration of a flash device according to a second embodiment.

FIG. 3 is a diagram showing a circuit configuration of a strobe device previously proposed by the applicant of the present application.

[Explanation of symbols]

1: charging circuit, 2: Trigger circuit, 3: Discharge capacitor, 4: Discharge tube, 5: primary electrode, 6, 7: secondary electrode, 11: oscillator circuit, 12: drive circuit, 13, 13A: Piezoelectric transformer, 14B, 14C, 20, 21: switch, 15, 16: diodes for rectification, 18: Rectifier circuit, 19, 19A: trigger control circuit, 25: Trigger line,

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) H05B 41/32 H05B 41/32 J H01L 41/08 A (72) Inventor Katsuyuki Ishikawa 3-8 Nishikanda, Chiyoda-ku, Tokyo -1 In Taiheiyo Cement Co., Ltd. (72) Inventor Toshiyuki Terada 400 Soya, Hadano City, Kanagawa Prefecture Stanley Electric Co., Ltd. Hadano Works (72) Inventor Tatsuya Goto 400, Soya, Hadano City, Kanagawa Prefecture F-terms in Hadano Works, Stanley Electric Co., Ltd. Reference) 2H053 BA01 BA06 BA21 BA23 BA25 BA78 3K098 AA09 AA11 5H730 AS04 AS18 BB57 BB61 EE06 EE07 EE16 EE48 FG01 FG07 XC20

Claims (3)

[Claims] 1. A discharge tube for flashing light, a capacitor for storing electric energy for causing the discharge tube to emit light, a charging circuit for charging the capacitor with electric energy, and a high voltage signal for promoting discharge of the discharge tube. What is claimed is: 1. A strobe device comprising: a trigger circuit; and a booster circuit including one piezoelectric transformer that is commonly used as a booster means for the charging circuit and the trigger circuit, wherein the trigger circuit includes the capacitor and the discharge tube. The strobe device is provided with switching means for disconnecting from a reference potential common to the charging circuit and the trigger circuit according to the operation of. 2. Further, according to the operation of the trigger circuit,
A second switching unit that disconnects at least the capacitor and the discharge tube from the secondary electrode of the piezoelectric transformer is provided, and the capacitor and the discharge tube are connected from the reference potential and the secondary electrode of the piezoelectric transformer. The strobe device according to claim 1, wherein a closed circuit is formed in the separated state. 3. The strobe device is a strobe device for a camera built in or attached to the camera, and the trigger circuit operates according to a shutter operation of the camera. Alternatively, the strobe device according to claim 2.