JPS61140099A - Discharge lamp lighting apparatus - 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 <Industrial Application Field> The present invention relates to an improvement in a filament preheating method in a discharge lamp lighting device such as a fluorescent lamp.

<Prior Art> FIG. 2 is a wiring diagram of an embodiment of the present invention, but for convenience of explaining the prior art, the configuration will be explained in terms of units.

In the figure, 1 is a fluorescent lamp having electrode filaments 2, 2, 3 is a choke L, resistors R, , R, trunked TR, , TR,, capacitor C, ,) known blocking oscillation consisting of a lance T5, etc. circuit, 4 is a resistor R,,R,
, transistor TR, 5 is a lighting voltage generating circuit, and 6 is a control section. The control unit 6 generates a preheating signal P in response to a lighting operation of a lighting switch (not shown) or the like.
It outputs REHT and lighting signal FLON,
Preheating signal PFCEHTtL level %: tcON-O
When the transistor TR of the FF circuit 4 becomes conductive, the blocking oscillation circuit 3 oscillates. Due to this oscillation, a preheating voltage ``1'' is generated in the secondary coils 3a, 3a of the transformer T1, and the filament 2.2 is preheated by the preheating current ``1''. Furthermore, when the lighting signal FLON becomes L level, the lighting voltage generation circuit 5 is activated, and high voltage is applied to the filament 2,
The configuration is such that the fluorescent lamp 1 is turned on when the voltage is applied between the voltages 2 and 2.

In the conventional technology, when the lighting operation is performed at time t as shown in FIG.
It oscillates at Hz, and preheating of the filaments 2, 2 is started by preheating voltage (1) with a peak voltage of 10V. Since the filaments 2 and 2 have a positive temperature coefficient with a small resistance value at room temperature, at the start of preheating, for example, while the peak value of the steady current is OJA, a rush current with a peak value of about 1.2A flows, and the time With the passage of time, the filament temperature rises and the current value decreases, and after about 3 seconds it approaches a steady value and the filament temperature reaches about 900°C. Therefore, at time t2, three seconds after the lighting operation, the lighting signal FLON is set to L level, and the lighting voltage generating circuit 5 outputs a high voltage to light the fluorescent lamp 1.

<Problems to be solved by the invention> In the case of the above-mentioned conventional technology, a preheating time of about 3 seconds is required before lighting, which causes a delay in lighting, and moreover, a rush current flows through the filament each time it is lit, causing the filament There is a problem in that it has a negative effect on lifespan. In order to eliminate this lighting delay, it is possible to preheat the filament at all times, but this causes the filament to constantly reach a high temperature of around 900°C, which shortens its lifespan and also increases power loss. A problem arises.

The present invention has been made with the object of solving these problems and providing a discharge lamp lighting device in which the filament preheating time is short, the filament has a long life, and power loss is small.

Means for Solving Problems> In order to achieve the above object, the present invention brings the filament into a semi-preheated state by intermittently applying a preheating current to the electrode filament in a standby state when the discharge lamp is turned off. The filament is kept in a steady state of preheating by switching the preheating current to continuous energization immediately before applying the lighting voltage. It is best to select the above preheating current intermittent cycle and energization duty to values that can maintain the filament temperature at a temperature that will not cause a rush current of a magnitude that would adversely affect the filament life when the current is restarted. good.
1 <Function> Since the filament is in a semi-preheated state, the time required to heat the filament to the temperature at which it can be lit is shortened, and the delay time for lighting is shortened, and a large rush current does not flow through the filament 5) .

<Example> Next, an example shown in FIGS. 1 and 2 will be described. FIG. 1 is a timing chart showing the filament preheating operation.

In this embodiment, unlike the prior art described above, the preheating signal P
As shown in FIG. 1, REHT is a pulse wave that repeats Tt'H level and L level at a constant cycle in a standby state when the fluorescent lamp 1 is off. Therefore, the operation of the blocking oscillation circuit 3 is intermittent, and the preheating current I is intermittently applied to the filament 2.2 as shown in the figure, so that the filament 2.2 is maintained in a semi-preheated state.

The intermittent period T and current duty of the preheating current 11 prevent the filament from cooling each time the current is stopped and causing a rush current to flow each time the current is restarted, and also prevent unnecessary power consumption and filament wear due to excessive heating of the filament. set to a value that prevents That is, the period T is set to be sufficiently short (for example, T -10 m5ec, and the energization duty is set to, for example, 50%, and the temperature rise time constant when the filament is heated and the temperature fall time constant when it is not heated) are sufficiently short. 9, the temperature of filament 2,2 is approximately 500℃
The temperature is maintained around the same temperature.

In this state, when the lighting operation is performed at time t, the preheating signal PREHT is at L level *mainly the preheating current 1
1 is continuously energized, and the filament 2.2 rises to the temperature of about 900°C required for lighting, but because it is semi-preheated to around 500°C, it reaches 900° in a short time of about 1 second.
Reach C. Therefore, the lighting signal FLON is set to LI/bell at 1 second after the lighting operation, and the lighting voltage generation circuit 5 is activated to generate a high voltage.
The light will turn on with a delay of about 1 second after the lighting operation.

In addition, in this embodiment, the 0N-OF of the blocking oscillation circuit
Since the preheating current is intermittent by F, it is easy to operate reliably with a simple circuit configuration.

<Effects of the Invention> The present invention maintains the electrode filament in a semi-preheated state by intermittent preheating current in the standby state, so the delay time from lighting operation to lighting can be shortened, and the rush flowing into the filament can be shortened. By reducing the current and eliminating unnecessary heating, the life of the filament can be extended, and wasteful power consumption can also be reduced.

[Brief explanation of the drawing]

FIG. 1 is a timing chart showing the operation of one embodiment of the present invention.
FIG. 2 is a wiring diagram similar to the above, and FIG. 3 is a timing chart showing the operation of the conventional example. 1...Fluorescent lamp, 2...Filament 3...
Blocking oscillation circuit, 4...0N-OFF circuit, 5... Lighting voltage generation circuit, 6... Control section.

Claims (1)

[Claims] 1. In the standby state when the discharge lamp is off, a preheating current is intermittently applied to the electrode filament to keep the filament in a semi-preheated state, and just before the lighting voltage is applied, the preheating current is switched to continuous energization to keep the filament in a steady preheated state. A discharge lamp lighting device characterized by: