JPS5916293A - Device for firing discharge lamp - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a discharge lamp lighting device of a half-cycle ignition type using a nonlinear dielectric element.

[Technical background of the invention and its problems]

In general, for discharge lamps, ballast loss can be reduced by keeping the input constant and reducing the tube current.

Downsizing of the ballast can be achieved. Especially when the discharge lamp is a fluorescent lamp, the intensity of the mercury spectrum, that is,
It has the characteristics of increasing the intensity of ultraviolet rays and increasing the luminous efficiency as a fluorescent lamp.

However, when the tube current is reduced, the tube voltage increases. For this reason, if you use only a normal lighting circuit, that is, a circuit configuration in which a discharge lamp is connected to an AC power source via a ballast, the discharge lamp will not function properly when the polarity is reversed every half cycle (
There was a problem that the light would go off when the light was fired again (re-ignition).

The solution to this problem is a lighting system called the every-half-cycle ignition system. This device uses high-voltage pulses to provide the voltage required to restart the discharge lamp every half cycle when the input is kept constant and the tube current is reduced. However, conventionally, a circuit for generating a restriking pulse every half cycle has had a complicated circuit configuration using a thyristor or the like.

Therefore, as a means to simplify this circuit, Japanese Patent Application Laid-Open No. 14400/1983 discloses a method in which a nonlinear dielectric element is used in a circuit that generates a restriking pulse every half cycle. As shown in FIG. 1, a discharge lamp 3 is connected to an AC source 1 via an inductive ballast 2, and a nonlinear dielectric element 4 is connected in parallel to the discharge lamp 3. still,
The coercive voltage Vc of the nonlinear dielectric element 4 is set lower than the tube ML of the discharge lamp 3 during lighting.

To explain the operation of this circuit, the nonlinear dielectric element 4
The properties of will be explained using the characteristic diagram shown in FIG. That is, the nonlinear dielectric element 4 has a hysteresis characteristic, and when the applied voltage becomes high to a certain extent, the nonlinear dielectric element 4 becomes saturated in the amount of charge. This value is the saturation charge Q
It is called c and is a value determined by the element if the temperature is constant. Then, even if the applied voltage is lowered, almost no charge is discharged. When the applied voltage is further lowered and the applied voltage has a reverse polarity and reaches a certain value, the charged charges suddenly start discharging, and the nonlinear dielectric element 4 is further charged with a reverse polarity. Then, the amount of charged charge immediately reaches the saturated charge amount QC. The voltage at this time is called coercive voltage Vc. Therefore, the nonlinear dielectric element 4 exhibits the action of a switching element that turns on and off before and after the coercive voltage Vc.

The operation of a circuit using this nonlinear dielectric element 4 will be explained using FIG. 3. Here, ■e indicates the tube voltage. In the figure, the solid line indicates the tube voltage ■e, and the nine-dot line indicates the power supply voltage. When VA changes polarity from negative to positive while the Sunzu discharge lamp 30 is lit,
The discharge lamp 3 momentarily stops discharging. Then, the voltage applied to the discharge lamp 3 gradually increases to #1. When the value of L reaches Vc, the current flows into the nonlinear dielectric element 4 as a charging ↑ current. When , the discharge is stopped. When the charging charge reaches Qc, the charging current stops instantly. At this time, an inductive effect occurs in the inductive ballast 2, and the high pressure nokurusu v
p is generated and applied to the discharge lamp 3, and the discharge is restarted. Such an operation is also performed when transitioning to a negative half cycle, and the discharge lamp 3 receives a re-ignition pulse Vp every half cycle.
to maintain the discharge. The fourth diagram shows the relationship between the current flowing through the nonlinear 1μ body element 4 and the applied voltage at this time.
It is a diagram.

Here, in order to reliably re-ignite the discharge lamp 3, the re-ignition pulse VpO value must be set to a sufficient value.

Although the value of this Vp depends on the inductance value of the inductive ballast 2, it was considered to be within the legal range based on the value of the saturation charge mQC of the nonlinear Hz element 4.

In other words, it was thought that if it was desired to increase the vpO value of the restriking pulse, it would be sufficient to increase the saturation charge EI QcO value.

However, as development progressed, it was found that even if the saturation charge amount Qc was made the same, restriking pulses Vp having the same peak value could not necessarily be obtained. That is, the saturated charge 3'i:
Even if Qc is made sufficiently large, sufficient restriking pulse Vp
There is a disadvantage that the discharge lamp 3 often goes out because the discharge lamp 3 cannot be obtained.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned drawbacks, and an object of the present invention is to provide a discharge lamp lighting device that can reliably relight a discharge lamp.

[Summary of the invention]

The present invention relates to a discharge lamp lighting device using a half-cycle ignition method, in which a discharge lamp is connected to an AC power supply via an inductive ballast, and a nonlinear dielectric element is connected in parallel with the discharge lamp. It was discovered that the rate of change in the amount of electric charge of the body element with respect to the voltage affects discharge maintenance, and the rate of change was determined when the input power of the discharge lamp was 0.4 IIμc when the input power of the discharge lamp was 1o[:W] or more and 601:'W:) or less. /v] enables the discharge lamp to be kept lit reliably.

[Embodiments of the invention]

The circuit configuration of the discharge lamp lighting device of the present invention is similar to the conventional circuit configuration shown in FIG. That is, a discharge lamp 3 is connected to the alternating current filter 1 via an inductive ballast 2, and one nonlinear dielectric element 4 is connected in parallel with the discharge lamp 3. Here, the difference from the conventional one is the electrical characteristics of the nonlinear dielectric element 4. The rate of change of the electric charge M of the body element 4 with respect to the pressure is the coercive voltage VcKtd, and the input power of the discharge lamp is 10 [W].
] or more 60 [W3 or less @o, 4(:]t C/V
) and more than 60 [W] i120 (W,':
Throat below I! kio, 6 CttC/V] JJ.

It is above.

The reason for this will be explained below. That is, using the circuit configuration shown in FIG. 1, lighting conditions were observed when the electrical characteristics of the nonlinear dielectric element 4 were different. At this time, discharge lamps with different tube voltages ve were used. As a result, the horizontal axis shows the maximum value Vm of the pressure waveform in input 1 (commercial 10 (7 in case of > (V)
140 in m (1! Voltage ■p for Vl Ic,
The rate of change in the amount of charge with respect to voltage [:dQ/dV:] when the coercive voltage Vc of the nonlinear dielectric element 4 is plotted on the vertical axis is taken to determine the limit curve that can keep the discharge lamp 3 lit, and it is shown in FIG. . Curve (a) shows a case where the lamp input is 20 [W], but almost the same curve is obtained when the lamp input is 10 [W] or more and 60 [W:].

The curve m (b) shown is 110 (W:], but the lamp input exceeds 60 (W) and it is 120 (W:]).
Almost identical curves are obtained for the following: Here, the upper left area of curves (a) and (b) in the figure is the area where lighting is possible.

This is because when the lamp input is constant and the tube diameter is reduced, the tube voltage Ve increases. Therefore, in order to sustain 9 discharges due to the high tube voltage ■e, the restriking pulse voltage vp
It is necessary to increase For this purpose, the rate of change in the coercive voltage of the nonlinear dielectric element with respect to the voltage of electric protection n) [μC/
9 curve (a).

Both (b) are curves that curve to the right.

Therefore, when the tube It and the pressure ve exceed 0.8 Vm, the period during which current flows through the discharge lamp 3 becomes short, and therefore the period during which the current stops flowing becomes long, making it impossible to maintain lighting.

In other words, in this region, 1 yen 9 firing pulses are 1oo
Even if the pressure is increased above o [V], lighting cannot be maintained, and the tube 7) i pressure "a" cannot be increased beyond this.

Therefore, when the tube voltage ve is set to 0.8 Vm or less, the lamp input from Fig. 5 is 10 CW] or more than 60 [W].
In the case below, if the change with respect to the voltage of Inn 1 load 11 ↓ - Qk is 0.4 [μC/V] or more, then the lamp power is 60
0.6 when exceeding [W'] and less than 120 [1'W)
It can be seen that a value of [μC/W] or more is sufficient.

It should be noted that for lamps with a lamp input exceeding 120 (W:), the power loss of the nonlinear dielectric element increases (
There is. This will be explained with reference to FIG.

FIG. 6 shows an equivalent circuit of the discharge lamp lighting device of the present invention. In other words, 几e is the equivalent load resistance, and
C□ and E□ are the ta loss low resistance capacitance of the nonlinear dielectric element and the pulse voltage source, respectively. As the lamp input power increases, the 9 equivalent load resistance decreases. As the equivalent load resistance decreases, the pulse voltage decreases. and c7111 To increase the combined pulse voltage, it is necessary to increase the capacitance Co, but even if the loss resistance RO does not increase, the charge/discharge current increases due to the increase in the capacitance Co, so the loss due to the resistor 1b increases. . Generally, loss resistance also increases, resulting in a double increase in power loss. Experiments have shown that this power loss increases rapidly when the lamp input power exceeds 120 [W]. Therefore, the lamp input power is 1
Must be 20 (W) or less.

As described above, it is the anti-IU of the nonlinear dielectric element 4 that provides the restriking pulse Vp necessary to keep the discharge lamp lit.
EE Rate of change of charge amount with respect to voltage at Vc [d
Q/dV) will be explained below.

The induced voltage generated in the ballast 2, that is, the restriking pulse V
If p is 'ill, and the flow is 1, then Vp = "4-¥. Here, L is the self-inductance of the ballast 2. On the other hand, ■ is the 1(-(flow) flowing into the ballast 2, This means that at the moment when the restriking pulse Vp occurs, the non-4'l type trigger [
In this equation, the voltage V is a function of time since it is the charging/discharging current of the body element 4, but it is a term that does not depend on the 1σ1 path configuration. Therefore, it can be seen that the pulse Q wave height Vp depends on L and K. In the half-cycle restriking method, L is made as small as possible to reduce the size of the ballast 2. Therefore, in this state, in order to raise the restriking pulse V13 (IQ), it is necessary to increase V. Therefore, the peak value of the restriking pulse vp is equal to the nonlinear dielectric element 4.
It depends on the saturation 1E load ILL Qc of '
It can be seen that it depends on c < +kai-.

In the above description, the discharge lamp 3 is explained using as an example a discharge lamp that does not require a starting device, but the present invention can also be applied to a fluorescent lamp.

! If fluorescent lamps are used in RVs, the weight of the entire device can be reduced by applying it to fluorescent lamp devices that can replace general incandescent light bulbs, which have been developed to reflect recent energy conservation trends.

Table 1 below lists specific numerical values of embodiments of the lighting device of the present invention in comparison with a conventional case that does not use a nonlinear dielectric element.

Table 1 (X- mark is induced voltage only by the ballast, w1tt flow.

(Tube voltage and pulse voltage are effective values) As is clear from this table, even if the lamp input is small, the intensity of the mercury's ultraviolet rays improves and it is possible to obtain the same brightness. This promises improved efficiency. Furthermore, as a result of throttling the current, the inductance of the ballast can be lowered, thus making it possible to reduce the weight and size of the ballast.

〔Effect of the invention〕

The present invention connects a discharge lamp to an AC power source via an inductive ballast, and connects a nonlinear dielectric element in parallel with this discharge lamp, so that the coercive voltage of the nonlinear dielectric element is lower than the tube voltage of the discharge lamp. At the same time, it is possible to reliably maintain the false re-ignition of the discharge lamp by changing the rate of change in the amount of charge at the coercive voltage with respect to the voltage.
Inconveniences such as disappearing can be resolved.

[Brief explanation of drawings]

Figure 1 is a circuit configuration diagram of a discharge lamp lighting device using a nonlinear dielectric element, Figure 2 is a charge thread characteristic diagram of the nonlinear dielectric element, and Figure 3 is a diagram of the discharge lamp lighting device shown in Figure 1. Operation explanatory diagram, Figure 4 is a current characteristic diagram of the nonlinear dielectric element, Figure 5 is the resistance of the nonlinear dielectric element 1...AC power supply, 2...inductive ballast, 3...discharge lamp . 4...Nonlinear dielectric element. Agent Patent Attorney Kensuke Chika (and 1 other person) Figure 1 Figure 3 Vp, Vp Figure 6 Figure 2 Figure 4 Figure 6 461

Claims (1)

[Scope of Claims] A discharge lamp connected to an AC power source via an inductive ballast and a nonlinear dielectric element connected in parallel to the discharge lamp, the coercive voltage of the 100 electric elements being teeth. 04 [μC/
A discharge lamp lighting device characterized in that the lamp input power is 60 CW, 3 ft, or more, and the lamp input power is 120 [W:) or less, 6 [μc/V] or more.