JPH0268889A - Discharge lamp lighting device - Google Patents

Abstract

PURPOSE:To reduce the change of brightness in the start by extinguishing an auxiliary lamp continuously or stepwise from the rated lighting to the extinction correspondingly to the luminous flux increase in the start of lighting. CONSTITUTION:An auxiliary lamp 5 is extinguished continuously or stepwise from the rated lighting to the extinction correspondingly to the luminous flux increase in the start of lighting a discharge lamp 4. As the lighting circuit 3 of the discharge lamp 4 and the valuable voltage circuit 7 of an incandescent lamp 6, those of general circuit structures may be used. For example, the valuable voltage circuit 7 can be formed of a DC constant voltage power source circuit or pulse phase control power source circuit compared and controlled by a standard voltage signal from a timer/voltage control circuit 8. Hence, the change of brightness in the start of lighting the discharge lamp can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a lighting device for a discharge lamp equipped with an auxiliary light for compensating for insufficient luminous flux.

[Conventional technology]

Discharge lamps used in heavy vehicle headlamps and the like do not provide sufficient luminous flux when started (cold start), and it takes several tens of seconds to reach the rated lighting. Furthermore, once the lamp is turned off, it cannot be restarted unless the tube temperature falls after a certain period of time. At this time, although it is possible to restart the lamp at a high voltage (hot start), it is extremely dangerous since it is necessary to apply a high voltage ranging from V to 20 KV to the discharge lamp. Therefore, it has been proposed to use, for example, an incandescent lamp as an auxiliary light to compensate for the lack of luminous flux when starting the discharge lamp.

That is, by turning on the incandescent lamp at the same time as the discharge lamp starts lighting, and turning off the incandescent lamp when the discharge lamp reaches its rated lighting state, it is possible to compensate for the lack of luminous flux when starting the discharge lamp. At this time, the lighting time of the incandescent lamp is set in advance by a timer. Furthermore, this incandescent lamp is designed to be turned on even when the discharge lamp goes out due to sudden fluctuations such as a momentary power outage.

FIG. 5 shows the luminous flux of the incandescent lamp and the luminous flux of the discharge lamp over time.

As described above, the incandescent lamp is turned on at the rated value at the same time as the discharge lamp starts, and the incandescent lamp is turned off after the predetermined time T (timer setting time) has elapsed, that is, when the discharge lamp reaches the rated value. In addition, even when the discharge lamp goes out, the incandescent lamp is turned on at that point, and when the discharge lamp becomes self-starting (restarts naturally), the above startup sequence is repeated and the discharge lamp is turned off. Turn off the light when enough luminous flux is obtained.

Note that turning off and self-starting of the discharge lamp can be detected from changes in the terminal voltage or current of the discharge lamp.

[Problem to be solved by the invention]

However, as mentioned above, in the conventional discharge lamp lighting device equipped with an incandescent lamp as an auxiliary light, the incandescent lamp is always lit with a constant luminous flux, that is, the rated lighting is performed, so when the discharge lamp is started, the luminous flux increases. As a result, the light becomes brighter than necessary, and since the incandescent light is turned off instantly, the brightness changes rapidly, giving the user a sense of discomfort. Furthermore, since the time required for obtaining a sufficient luminous flux from the discharge lamp varies depending on the ambient temperature and tube temperature, there is a problem in that even if this is done, the brightness changes greatly.

The present invention has been made in view of these problems, and it is an object of the present invention to provide a discharge lamp lighting device that has little change in brightness and does not give a user a sense of discomfort.

(Means for Solving the Problems) The discharge lamp lighting device of the present invention continuously operates an auxiliary light for a predetermined period of time from rated lighting to extinguishment in response to an increase in luminous flux at the start of lighting of a discharge lamp. Alternatively, dimming lighting means for dimming the light in stages is provided.

Further, the discharge lamp lighting device of the present invention is the lighting device described above, in which the auxiliary lamp is turned on even when the discharge lamp is turned off.

(Function) In the discharge lamp lighting device of the present invention, the dimming lighting means dims the auxiliary lamp continuously or stepwise at the time of starting the discharge lamp. Therefore, there is no possibility that the luminous flux of the discharge lamp will become brighter than necessary as the luminous flux of the discharge lamp increases, or that the brightness will not change due to instantaneous extinguishing of the auxiliary lamp.

〔Example〕

FIG. 1 is a circuit diagram showing an embodiment of the present invention.

In the figure! 2 is a lamp switch, and 3 is a lighting circuit for lighting the discharge lamp 4, which is composed of a transformer, an inverter, and the like.

, 5 is an incandescent lamp provided as an auxiliary light to compensate for the lack of luminous flux of the discharge lamp 4, and 6 is an incandescent lamp provided as an auxiliary light to compensate for the lack of luminous flux of the discharge lamp 4; A dimming lighting means that dims the light in stages or in stages.
It is comprised of a variable voltage circuit 7 that changes the voltage applied to the incandescent lamp 5, a timer for setting the predetermined time, and a timer/voltage control circuit 8 that controls the voltage applied to the incandescent lamp 5. Reference numeral 9 denotes a starting/turning-off detection circuit for detecting starting and turning-off of the discharge lamp 4.

FIG. 2 is a circuit diagram showing an example of the start/off detection circuit 9. This circuit is designed to detect the current of the discharge lamp 4. In the figure, 10 is a transformer, D is a rectifying diode, R, R, is a resistor, C1 is a smoothing capacitor, and Q+ is a transistor. be. FIG. 3 is a circuit diagram showing an example of the timer/voltage control circuit 8, and Q2 in the figure is a circuit diagram showing an example of the timer/voltage control circuit 8.
゜Q3 is a transistor, R1-R6 are resistors, and C2 is a capacitor.

Next, the operation will be explained.

The incandescent lamp 5, which is an auxiliary light, is turned on not only when the discharge lamp 4 is started but also when the discharge lamp 4 is turned off. Fourth
The figure shows the relationship between the luminous flux of the incandescent lamp 5 and the luminous flux of the discharge lamp 4. When the lamp switch 2 is turned on, the lighting circuit 3 is activated and the discharge lamp 4 is started. The starting of the discharge lamp 4 is detected by the starting/turning-off detection circuit 9. At this time, as shown in FIG. 4, in response to the increase in the luminous flux of the discharge lamp, the incandescent lamp 5 changes from the rated lighting state to 10% of the rated luminous flux.
The light is gradually dimmed over a predetermined time T until the light reaches the desired level, and the light is turned off. At this time, the timer/voltage control circuit 8 outputs a reference voltage signal for a predetermined period of time T to the variable voltage circuit, and this reference voltage signal causes the incandescent lamp 5 to be applied so that the luminous flux shown in FIG. The voltage is controlled.

Furthermore, if the tube temperature is still high after the discharge lamp 4 has been turned off, the discharge lamp 4 will not start. At this time, the discharge lamp 4 is in a high impedance state and no current flows. When the start/off detection circuit 9 detects this, the timer/voltage control circuit 8 outputs a reference voltage signal of the maximum voltage, and the incandescent lamp 5 is lit at the rated value. Thereafter, when the tube temperature of the discharge lamp 4 falls below a predetermined temperature, starting of the discharge lamp 4 is started. At this time, the impedance of the discharge lamp 4 rapidly decreases, and current flows. When this change in current, that is, the restart of the discharge lamp 4, is detected by the starting/going out detection circuit 9, the timer/voltage control circuit 8 is reset, and the timer/voltage control circuit 8 is used to detect the incandescent lamp 5 in FIG. A reference voltage signal corresponding to the attenuation luminous flux curve is output. Then, the incandescent lamp 5 is dimmed and controlled in the same way as at the time of startup described above, and is turned off after the predetermined time T has elapsed.

In this way, since the starting, extinguishing, or self-starting of the discharge lamp 4 is automatically detected, and the luminous flux of the incandescent lamp 5 is controlled according to the luminous flux of the discharge lamp 4, when the discharge lamp 4 is started, The brightness does not become more bright than necessary, the incandescent lamp 5 does not turn off instantaneously, and there are few sudden changes in brightness. Furthermore, even if the time required to obtain the rated luminous flux varies due to differences in the ambient temperature of the discharge lamp 4 and the temperature at the time of starting, the user will not feel uncomfortable because there is no sudden change in brightness. Furthermore, since high voltage restart of 10KV to 20KV is not performed, it is safe for users.

Note that the lighting circuit 3 of the discharge lamp 4 and the variable voltage circuit 7 of the incandescent lamp 5 may have a general circuit configuration; for example, the variable voltage circuit 7 is comparatively controlled by a reference voltage signal from the timer/voltage control circuit 8. It can be configured with a DC constant voltage power supply circuit or a pulse phase control power supply circuit. The starting/turning-off detection circuit 9 is not limited to the one shown in FIG. 2, and may be a circuit that detects the terminal voltage of the discharge lamp 4, for example.

In this case, the fact that the terminal voltage of the discharge lamp 4 drops after it is started is utilized. The timer/voltage detection circuit 8 is not limited to that shown in FIG. 3, but may be used as long as it can perform control similar to the change in luminous flux shown in FIG. 4 as the dimming lighting means 6. In addition to the incandescent lamp 5 of the embodiment, a halogen lamp or the like can also be used as the auxiliary lamp.

(Effects of the Invention) As described above, according to the present invention, the auxiliary lamp is dimmed continuously or in stages for a predetermined period of time from rated lighting to extinguishing in response to the increase in luminous flux at the time when the discharge lamp starts lighting. Since a dimming lighting means is provided, the luminous flux of the auxiliary lamp can be controlled according to the luminous flux of the discharge lamp, which has the effect of reducing sudden changes in brightness and causing no discomfort to the user. In addition, even if the time required for sufficient luminous flux to be obtained from the discharge lamp varies depending on the ambient temperature and tube temperature, changes in brightness can be reduced, and it is safe because it does not require high-voltage restart. effective.

[Brief explanation of the drawing]

FIG. 1 is a circuit configuration diagram showing an embodiment of the present invention, FIG. 2 is a circuit diagram showing an example of the start/off detection circuit of FIG. 1,
Figure 3 is a circuit diagram showing an example of the timer/voltage control circuit in Figure 1, Figure 4 is a timing diagram showing the relationship between the luminous flux of an incandescent lamp and the luminous flux of a discharge lamp in the lighting device of Figure 1, and Figure 5. 1 is a timing chart showing the relationship between the luminous flux of an incandescent lamp and the luminous flux of a discharge lamp in a conventional discharge lamp lighting device. 1.--Battery 2.--Lamp switch 3.--Lighting circuit 4.--Discharge lamp 5.--Incandescent lamp (auxiliary light) 6.--One dimming lighting means 7-----Variable voltage circuit 8...-Timer/voltage control circuit 9---Start/off detection circuit Applicant: Stanley Electric Co., Ltd.

Claims (2)

[Claims] (1) In a lighting device that turns on an auxiliary light for a predetermined period of time to compensate for a lack of luminous flux when starting a discharge lamp, the auxiliary light is turned on for the predetermined period of time from rated lighting to extinguishing in response to an increase in luminous flux when the discharge lamp starts lighting. A discharge lamp lighting device characterized by being provided with dimming lighting means for dimming the light continuously or stepwise. (2) The discharge lamp lighting device according to claim 1, characterized in that an auxiliary light is turned on when the discharge lamp goes out.