JPH0619198Y2 - EL light emitting device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention The present invention relates to an EL light emitting device (electroluminescent device).

2. Description of the Related Art As a device for obtaining a voltage for causing an EL element to emit light by a converter circuit, for example, a device described in Japanese Utility Model Publication No. 50-9958 has been proposed.

This device is a strobe device, and as shown in FIG. 3, includes an oscillating transistor 2, an oscillating transformer 3, a rectifying diode 4 and the like, and a DC power supply 5 supplied via switches SW ₁ and SW _2. The secondary side AC output of the well-known DC-DC converter circuit 1 for boosting the terminal voltage of the above and charging the main capacitor 6 is supplied to the EL element 7.

Therefore, during operation of the DC-DC converter circuit 1, the EL element 7 will emit light by the AC voltage of the oscillation frequency of the oscillation transformer 3.

Problems to be Solved by the Invention Such an EL light emitting device utilizes the converter function of the DC-DC converter circuit 1 normally provided in the strobe device, and does not require addition of special parts. It is possible to obtain a voltage for causing the EL element 7 to emit light.

However, regarding the life characteristics of the EL element 7,
Since the carrier frequency of the DC-DC converter circuit 1 is a high frequency of the order of KHz, the above-mentioned apparatus is not so preferable.

That is, the life of the LE element becomes longer as the frequency of the applied voltage becomes lower. Therefore, when the secondary winding output having a high frequency of KHz order is continuously applied during the operation of the DC-DC converter circuit, the EL element becomes The life will be shortened.

On the other hand, if the oscillating frequency of the DC-DC converter circuit is lowered, no inconvenience will occur in terms of life characteristics. However, in general, when the oscillating frequency is lowered while maintaining the same conversion efficiency, the size of the transformer inevitably increases. And
It will be extremely difficult to use it in strobe devices and other devices that are desired to be smaller and lighter.

The present invention has been made in consideration of such problems, and an object thereof is to provide an EL light emitting device using a converter circuit, which does not increase the size and has a good life characteristic.

The EL light emitting device according to the present invention includes an oscillation transformer having at least a primary winding and a secondary winding, and an oscillation transistor having a collector connected to the primary winding, a base of the oscillation transistor, and a primary winding. And a starting circuit of an oscillating transistor connected to the line, and by operating, boosts the terminal voltage of the DC power supply supplied to the primary winding through the collector and emitter of the oscillating transistor, and A converter circuit that outputs an alternating voltage to a line, a switch element that is arranged in a supply loop of a direct-current power supply voltage to a primary winding through an oscillating transistor, and forms a supply loop by being turned on, and this switch element An oscillating circuit for turning on and off a predetermined cycle and an AC voltage output to the secondary winding are supplied to emit E And an L element.

Operation Since the EL light emitting device according to the present invention is configured as described above, the generation of the voltage output to the secondary winding is generated in this oscillation circuit by controlling the switching element to be turned on and off by the oscillation circuit. The frequency is controlled to a predetermined repetition frequency set by the above. That is, the output voltage of the secondary winding of the oscillation transformer is generated while the switch element is in the conductive state, and does not occur while the switch element is controlled to be in the non-conductive state.

EXAMPLE FIG. 1 is an electric circuit diagram showing an example of an EL light emitting device according to the present invention. In the figure, the same symbols as those in FIG. 3 indicate the same functional members.

In this embodiment, an oscillating transformer 3 having a primary winding 3 ₁ , a secondary winding 3 ₂ , and an auxiliary winding 3 _3, and a collector having a primary winding 3 ₁
And an oscillation transistor 2 connected to the primary winding 3 ₁ and a base of the oscillation transistor 2 and a starting circuit 12 for the oscillation transistor 2 together with the auxiliary winding 3 _3.
A converter circuit 8 provided with a resistor 13 to form a, is provided in the supply Rupupu L of the oscillation transistor 2 and the primary winding 3 ₁ of the DC power source 5, the transistor 9 is a switch element, the base of the transistor 9 outputs a pulse signal of a predetermined frequency to the output terminal 10 ₁ is connected to the oscillation circuit for controlling the operation of the transistor 9 10, E
L element 7 and are connected in series, and a capacitor 11 which controls the value of the voltage applied to the EL element 7 generated in the secondary winding 3 _2.

Note that the oscillation circuit 10, so as to operate in a means such as a start switch when it is desired to emit light EL element 7 (not shown), also iterator to the capacitor 11, the primary winding 3 ₁ and the secondary winding by choosing the turns ratio of 3 _2,
If the output voltage value is adjusted to an appropriate value, each can be omitted.

In the embodiment shown in FIG. ₁ , when the operation of the oscillator circuit 10 is started at time t ₁ so that the EL element 7 emits light, the output terminal 10 ₁ has the output shown in FIG. 2 (a). A pulse signal having a predetermined cycle T is output and supplied to the base of the transistor 9. Thereby, the transistor 9
Is a period t ₁ to t ₂ during which the oscillation circuit 10 outputs a predetermined voltage,
Since the base current is supplied at _{t 3} ~t _4, t 5 ~t between _6, it made conductive, the period prescribed voltage is not output _{t 0 ~t 1, t 2 ~t} 3, t 4 ~t 5 between In, the base current is not supplied and the state becomes non-conductive.

When the transistor 9 becomes conductive, the direct current power source 5 causes the emitter-base of the oscillation transistor 2 to start, and the starting circuit 1 to operate.
2, a current flows through the transistor 9, and the oscillation transistor 2 is turned on together with the transistor 9. As a result, the DC power supply 5, the emitter-collector of the oscillation transistor 2, the primary winding 3 ₁ , the transistor A current loop L consisting of 9 collector-emitters is formed.

When the current loop L is formed, the converter circuit 8 including the oscillating transistor 2, the oscillating transformer 3, and the starting circuit 12 starts a known oscillating operation.

On the other hand, when the transistor 9 is completely turned off, the loop L described above is not formed, and thus the converter circuit 8
The oscillation operation of will be stopped.

That is, the converter circuit 8 performs the well-known oscillation operation only while the transistor 9 is in the conductive state.
An AC voltage based on the oscillation frequency of the oscillation circuit 10 as shown in FIG. 2B is output between the output terminals A and B.

The AC voltage output between the output terminals A and B in response to the operation of the oscillation circuit 10 is supplied to the EL element 7 via the capacitor 11, and the EL element 7 includes the capacitors 11 and E.
A voltage obtained by dividing the AC voltage by the capacitance ratio of the L element 7 is applied to emit light. This light emitting operation is shown in Fig. 2 (b).
It is done intermittently as shown in.

The oscillation frequency of the oscillation circuit 10 that controls the operation of the converter circuit 8 and outputs an AC voltage in a predetermined cycle is based on the life of the EL element 7 or the emission mode, that is, whether intermittent emission or continuous emission is good. Considering this, the frequency may be appropriately set to an appropriate low frequency.

As described above, according to the present embodiment, the converter circuit 8 oscillates intermittently when the transistor 9 is turned on and off.
Since the EL element 7 emits light intermittently based on the oscillation frequency of the oscillation circuit 10, the life of the EL element 7 can be extended as compared with a device in which an alternating voltage of a high frequency is constantly applied. Then, since it is only necessary to intermittently apply the AC voltage to the EL element 7, it is possible to use the small-sized oscillation transformer 3, so that the converter circuit 8 can be downsized.

Further, when the present embodiment is applied to a strobe device, the converter circuit 8 can also be used for charging the main capacitor, for example, but in such a case, since there is an oscillation pause period, the charging time of the main capacitor is reduced. Can be long. At this time, it is preferable that this EL light emitting device is configured independently of the strobe device.
It should be noted that the independent configuration increases the number of parts and leads to an increase in the size of the apparatus, but as described above, the size of the present embodiment itself is small, so that the size is not particularly large.

EFFECTS OF THE INVENTION According to the EL light emitting device of the present invention, since it has the switch element for controlling the oscillation operation of the converter circuit,
Since the L element performs the intermittent light emitting operation based on the oscillation frequency of the oscillation circuit, it is possible to prolong the life of the EL element as compared with a device to which an alternating voltage with a high frequency is constantly applied.

Since it is only necessary to intermittently apply the AC voltage to the EL element, a small oscillation transformer can be used,
The converter circuit can be downsized.

[Brief description of drawings]

FIG. 1 is an electric circuit diagram of an embodiment of an EL light emitting device according to the present invention, and FIGS. 2 (a) and 2 (b) are output waveform diagrams of the oscillator circuit 10 and output waveforms between terminals A and B in FIG. 3 and 4 are electric circuit diagrams of a conventional EL device. 2 ... Oscillation transistor, 3 ... Oscillation transformer, 5 ...
DC power supply, 7 ... EL element, 8 ... Converter circuit, 9
...... Transistor (switch element), 10 ... Oscillation circuit, 11 ... Capacitor, 12 ... Startup circuit.

Claims (3)

[Scope of utility model registration request] 1. An oscillation transformer having at least a primary winding and a secondary winding, an oscillation transistor having a collector connected to the primary winding, and an oscillation transistor connected between the base of the oscillation transistor and the primary winding. An oscillation transistor start-up circuit is included, and when operated, the terminal voltage of the DC low-voltage power supply supplied to the primary winding through the collector-emitter of the oscillation transistor is boosted to supply an AC high voltage to the secondary winding. An output converter circuit, a switch element that is arranged in a supply loop of the DC power supply voltage to the primary winding through the oscillation transistor, and forms a supply loop by being turned on, and an operation of the switch element. And an EL element that emits light by being supplied with the AC voltage output to the secondary winding. Ranaru EL light-emitting device. 2. The EL light emitting device according to claim (1), wherein the EL element is supplied with an AC voltage output to the secondary winding through a capacitor. 3. The oscillator circuit has an output terminal connected to the control pole of the switch element, and outputs a pulse signal of a predetermined frequency to the output terminal by operating the utility circuit. The EL light-emitting device according to the item).