JPH03257794A - Electric discharge lamp lighting device - Google Patents

Abstract

PURPOSE:To conduct lighting with an ideal startup characteristic irrespective of an internal state of an electric discharge lamp by providing a photoelectric transfer part for converting electric discharge lamp output light into an electric signal to output, and controlling the electric discharge lamp on the basis of the signal. CONSTITUTION:A photoelectric transfer part 5 receives output light of a high intensity electric discharge lamp 2 and converts the light into an electric signal for outputting. A driving control circuit 3 controls the high intensity electric discharge lamp 2 on the basis of the signal provided by the photoelectric transfer part 5. Accordingly, control can be conducted by catching light flux generated by the high intensity electric discharge lamp 2 itself independent from an internal state of the high intensity electric discharge lamp 2. According to this constitution, the high intensity electric discharge lamp 2 can be lighted with an ideal startup characteristic, irrespective of the internal state of the high intensity electric discharge lamp 2.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a discharge lamp lighting device for lighting a high-intensity discharge lamp, and a photoelectric device that receives output light from a high-intensity discharge lamp, converts it into an electrical signal, and outputs it. By controlling the high-intensity discharge lamp based on the signal given from the photoelectric conversion unit,
This enables the high-intensity discharge lamp to be lit with ideal start-up characteristics substantially regardless of the internal state of the high-intensity discharge lamp.

<Prior art> Fig. 4 is a diagram showing the configuration of a discharge lamp lighting device using a high-intensity discharge lamp, in which 1 is a power source, 2 is a high-intensity discharge lamp, 3 is a drive control circuit, and 4 is a voltage detection circuit. , 42 is a current detection circuit, and S is a switch.

The high-intensity discharge lamp 2 has a structure in which a rare gas, mercury, metal halide 22, etc. are contained in a tube 21 made of quartz glass, etc., and electrodes 23 and 24 are opposed to each other at a distance within the tube 21. It has become.

The drive control circuit 3 includes a DC-DC converter that converts the DC input from the power supply 1 into a high-level DC voltage, a high-voltage generation circuit and control circuit that switches the output to generate high-voltage pulses, and has a high-voltage generation circuit. Electrode 2 of luminance discharge lamp 2
For example, a high voltage pulse of about 10 to 15 Kv is applied between 3 and 24.

The drive control circuit 3 controls the lighting state of the discharge lamp 2 based on detection signals manually inputted from the voltage detection circuit 4 and the current detection port 42.

When a high voltage pulse is applied to the electrodes 23 , 24 an arc discharge occurs and an electrical discharge occurs through the gas in the tube 21 .

The heat generated by this discharge causes the halide metal 2 to
2 is vaporized and the maximum amount of light is emitted. After lighting, relatively low pulses are continuously applied.

High-intensity discharge lamps 2 are different from halogen lamps, which have traditionally been widely used as automobile headlights, because they generate light by discharging in gas, and are about 1/3 of the halogen lamps. Despite the power consumption, Part 3
By obtaining up to 4 times the luminous flux, it is extremely useful as a headlamp for rice and automobiles. Automobile headlights have a large impact on automobile design, and high-intensity discharge lamps, which are based on miniaturized shapes, can have an extremely large impact on automobile design.

When using high-intensity discharge lamps as automobile headlights, strict standards such as the SAE standard are imposed regarding instant lighting, life characteristics, and lighting stability in order to ensure vehicle driving safety. ing. FIG. 5 is a diagram showing the light output time characteristics required by the above standard at the time of a cold start, with time (seconds) plotted on the horizontal axis and relative luminous flux (%) plotted on the vertical axis. The relative luminous flux is the steady state luminous flux output of 1
It is shown as a percentage when it is set to 00%. Shaded areas A and B are non-permissible areas;
Area C between area B is the permissible area. High intensity discharge lamp 2
must be controlled so that the lighting characteristics fall within the allowable region C, as shown by the curve Il. The characteristics shown in FIG. 5 can be understood as follows.

First, in order to ensure instant lighting, after the switch S is turned on and a high voltage pulse is applied to the high-intensity discharge lamp 2, a relative luminous flux of 25% is obtained within about 0.5 seconds. Approximately 80% relative luminous flux must be generated within seconds.

Moreover, at the time of startup, the relative luminous flux must be suppressed to less than 150% in order to satisfy the life characteristics.

Furthermore, in order to ensure lighting stability, the relative luminous flux in steady state must fall within an error of ±10%.

Conventionally, as a means to meet the standards shown in FIG. The applied voltage was controlled. However, it is extremely difficult to satisfy the standards shown in FIG. 5 using such means.The reason for this will be explained next.

(A) A headlamp composed of a high-intensity discharge lamp 2 is often used in a blinking manner, for example, by a passing operation. Even in such a case, the standards shown in FIG. 5 must be basically met. However, relighting is normally performed with the tube 21 heated, resulting in lighting characteristics different from those in the case of a cold start. Therefore, it is extremely difficult to relight the high-intensity discharge lamp 2 within the specifications shown in FIG.

(B) The tube temperature at the time of re-lighting varies depending on the time when the high-intensity discharge lamp 2 goes out and the time it goes out, etc., and the temperature detection,
Management is virtually impossible. The gasification state inside the tube 201 varies significantly depending on the tube temperature, and the current and voltage are greatly influenced by the gasification state inside the tube 201. The conventional technology for controlling the high-intensity discharge lamp 2 by detecting current and voltage attempts to control the high-intensity discharge lamp 2 by detecting the current and voltage corresponding to the impossible-to-understand conditions inside the tube. It is extremely difficult to meet the standards shown in Figure 5.

(C) At cold start, as shown in Figure 5,
After the switch 4 is turned on, the rising characteristic must be satisfied such that the relative luminous flux becomes 25% in 0.5 seconds and about 80% in 2 seconds. However, if the starting current is increased in an attempt to satisfy this requirement, the rise characteristic will become like curve I12, and there is a possibility that the relative luminous flux will exceed 150%. When the relative luminous flux is controlled so as not to exceed the limit of 150%, the rise characteristic becomes curve i13.
There is a risk that someone will be inside the non-permissible area A.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above-mentioned conventional problems and to provide a discharge lamp capable of lighting a high-intensity discharge lamp with ideal start-up characteristics, substantially regardless of the internal state of the high-intensity discharge lamp. The purpose of the present invention is to provide a lighting device.

Means for Solving the Problems> To solve the above problems, the present invention provides a discharge lamp lighting device including a high-intensity discharge lamp that emits light by gas discharge inside the tube, a drive control circuit for the lamp, and a photoelectric conversion section. The photoelectric conversion section is a circuit that receives the output light of the high-intensity discharge lamp, converts it into an electric signal, and outputs it, and the drive control circuit converts the output light based on the signal given from the photoelectric conversion section. The present invention is characterized in that the high intensity discharge lamp is controlled.

<Operation> The photoelectric conversion section receives the output light of the high-intensity discharge lamp, converts it into an electrical signal, and outputs the electrical signal. The drive control circuit controls the high intensity discharge lamp based on the signal given from the photoelectric conversion section. Therefore, the luminous flux generated by the high-intensity discharge lamp itself can be captured and controlled independently and substantially independently of the internal state of the high-intensity discharge lamp. Therefore, the high-intensity discharge lamp can be lit with ideal start-up characteristics, not only during a cold start but also during relighting, substantially regardless of the internal state of the high-intensity discharge lamp.

<Embodiment> FIG. 1 is a diagram showing the configuration of a discharge lamp lighting device according to the present invention. In the figure, the same reference numerals as in FIG. 3 indicate the same components. 5 is a photoelectric conversion section.

The photoelectric conversion unit 5 receives the output light from the high-intensity discharge lamp 2, converts it into an electrical signal, and outputs the electrical signal. The photoelectric conversion unit 5 has a configuration that combines an optical system that receives output light and a photoelectric conversion element such as a phototransistor that converts the received optical signal into an electrical signal, or a configuration that combines an optical system and a photoelectric conversion element that converts the received optical signal into an electrical signal. Any of the following configurations may be used. In the former case, an optical system such as an optical fiber or lens is interposed between the high-intensity discharge lamp 2 and the photoelectric conversion element, and in the latter case, the output light of the high-intensity discharge lamp 2 is transferred to the photoelectric conversion element. The structure is such that it receives light directly.

The drive control circuit 3 controls the high intensity discharge lamp 2 based on the signal given from the photoelectric conversion section 5. The drive control circuit 2 controls the high-intensity discharge lamp 2 by setting a certain target value for the output luminous flux of the high-intensity discharge lamp 2 and controlling the high-intensity discharge lamp 2 so that the output luminous flux of the rice grains reaches this target value. It's like controlling the current or voltage that flows. The target value in this case is generally the output luminous flux during steady lighting.

In this way, independently of the internal state of the high-intensity discharge lamp 2,
Since the light output of the high-intensity discharge lamp 2 itself can be detected and controlled substantially independently of this, it is virtually independent of the internal state of the high-intensity discharge lamp 2, not only during a cold start but also when restarting. , the ideal rise characteristic J21 (
(see FIG. 5), the high-intensity discharge lamp 2 can be turned on.

FIG. 2 shows a specific circuit configuration. In the drive control circuit 3, 301 is a DC-DC converter, 302 is a control circuit, 303 is an operational amplifier, 304 and 305 are switching elements, 306 is a drive transformer, 307 is a capacitor, 308 is an inductor, 309 is a capacitor, 310 to 313 is a diode, 314 is a resistor, 315
is the reference power supply.

The DC-DC converter 301 converts the DC voltage provided from the DC power supply 1 into a higher voltage DC voltage and outputs the DC voltage. DC power supply 1 is DC12V or DC24 in cars etc.
It is a low voltage of V. Therefore, the DC-DC converter 30
1 converts the level into a DC voltage necessary for lighting the discharge lamp and outputs it.

Control circuit 302 controls switching elements 304 and 305. In this embodiment, the switching element 304,
This will be explained as a voltage-frequency converter that variably controls the number of switching frequencies to be applied to 305.

The operational amplifier 303 outputs a voltage signal E0 according to the reference voltage signal E1 given from the reference power supply 315 and the voltage signal E2 given from the photoelectric conversion section 5.

The switching elements 304 and 305 are constituted by field effect transistors, bipolar transistors, or the like. These switching elements 304 and 305 perform switching operations in response to signals given from the control circuit 302. The switching element 304 performs a switching operation at the frequency of the control signal applied from the control circuit 302 through the drive transformer 306, and switches the DC voltage applied from the DC-DC converter 301.

The switching element 305 is controlled by the control circuit 302 so as to be turned on during the off period of the switching element 304.

Inductor 308 and capacitor 309 constitute a resonant circuit. Switching elements 304 and 305 set the resonant frequency f of this resonant circuit. When a switching operation is performed,
A high resonant voltage appears in the resonant circuit formed by inductor 308 and capacitor 309. This resonant voltage is applied to the high-intensity discharge lamp 2, and the high-intensity discharge lamp 2 is triggered.

The photoelectric conversion unit 5 includes a photoelectric conversion element 51, a bias power source 52, a resistor 53, a capacitor 54, and the like. The photoelectric conversion element 51 is constituted by a phototransistor, and is optically coupled to the high-intensity discharge lamp 2 so as to receive its output light.

Immediately after the switch S is closed and the power supply 1 is turned on, the high-intensity discharge lamp 2 does not emit light, and the photoelectric conversion element 51 is substantially in an open state. At this time, the control circuit 302 controls the switching frequency of the inductor 308 and the capacitor 3.
Resonant frequency f of the resonant circuit according to 09. The switching elements 304 and 305 are driven accordingly. As a result, a resonant high voltage pulse is applied to the electrodes 23, 24 of the high-intensity discharge lamp 2, and arc discharge occurs between the electrodes 23-24.

During the arc discharge period at startup, the luminous flux output from the high-intensity discharge lamp 2 is at a low level, so the photoelectric conversion unit 5
The level change of the voltage signal E2 inputted to the operational amplifier 303 from the operational amplifier 303 is extremely small. is at a low level. Therefore, at startup, the switching elements 304 and 305 are driven at a low frequency, a large current is supplied to the high-intensity discharge lamp 2, and the heat generated by the arc discharge causes the halide metal inside the high-intensity discharge lamp 2 to is rapidly vaporized in a short period of time and enters a high brightness lighting state in a short period of time.

In the lit state, a large amount of light is emitted from the high intensity discharge lamp 2. The luminous flux emitted from the high-intensity discharge lamp 2 is received by the photoelectric conversion element 51, and the potential of the collector C decreases.

Therefore, the level of the voltage signal E2 inputted to the (-) terminal of the operational amplifier 303 decreases, so that the operational amplifier 30
3, the voltage signal Eo outputted from the voltage signal Eo increases. As a result, the control circuit 302 controls the switching element 30
4. The switching frequency of 305 is controlled in the direction of a higher frequency than that at the rise time. As a result, the peak value of the current pulse applied to the high-intensity discharge lamp 2 is reduced, and eventually a constant and stable voltage pulse is provided.

In the steady state, the voltage signal E2 and the output voltage signal E are supplied to the operational amplifier 303 in response to changes in the luminous flux of the high-intensity discharge lamp 2. The light flux changes accordingly and is controlled to maintain a constant luminous flux.

FIG. 3 is a diagram showing a specific arrangement. 6 is a reflector, 7
is the car body. The photoelectric conversion element 51 is installed inside the reflector 6 at a position where it can receive light from the high-intensity discharge lamp 2. The photoelectric conversion sections other than the photoelectric conversion element 51 and the drive control circuit 3 are preferably arranged outside the reflector 6. As another arrangement example, a configuration in which the output light of the high intensity discharge lamp 2 is received by an optical fiber and guided to a photoelectric conversion element and a photoelectric conversion section provided at an appropriate position such as outside the reflector 6 is also effective. .

The high-intensity discharge lamp 2 is placed at the focal point of the reflector 6,
The light emitted from the high-intensity discharge lamp 2 is reflected and radiated into substantially parallel light rays. The external light, which is parallel light, is reflected by the reflector 6 and focused on a certain position of the high-intensity discharge lamp 2 . Therefore, by arranging the light conversion element 51 at the illustrated position, the influence of external light can be eliminated.

<Effects of the Invention> As described above, the discharge lamp lighting device according to the present invention includes a photoelectric conversion unit that receives the output light of a high-intensity discharge lamp, converts it into an electric signal, and outputs it, and receives the output light from the photoelectric conversion unit. Since the high-intensity discharge lamp is controlled based on the signal received, ideal start-up characteristics can be achieved not only during a cold start but also when re-lighting, virtually regardless of the internal state of the high-intensity discharge lamp.
A discharge lamp lighting device capable of lighting a high-intensity discharge lamp can be provided.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of a discharge lamp lighting device according to the present invention,
FIG. 2 is a diagram showing a specific circuit configuration thereof, FIG. 3 is a diagram showing a specific example of its arrangement, FIG. 4 is a diagram showing a configuration of a conventional discharge lamp lighting device, and FIG. FIG. 3 is a diagram showing the relative luminous flux time characteristics required by the standard for cold start. 2... High intensity discharge lamp 3... Drive control circuit 5...
Photoelectric conversion section

Claims (1)

[Claims] (1) A discharge lamp lighting device including a high-intensity discharge lamp that emits light by gas discharge inside the tube, a drive control circuit thereof, and a photoelectric conversion section, wherein the photoelectric conversion section is configured to output an output of the high-intensity discharge lamp. A discharge lamp lighting device, which is a circuit that receives light, converts it into an electric signal, and outputs it, and the drive control circuit controls the high-intensity discharge lamp based on a signal given from the photoelectric conversion section. .