JPH04118330A - Headlamp for vehicle - Google Patents

Abstract

PURPOSE:To improve reliability of a headlamp, to get its compactness and lightness, and to suppress decrease of the quantity of the light in a four lamp type headlamp which has a main beam and a dimmer beam in one body by constituting the headlamp so that any one of the main beam and the dimmer beam is an incandescent lamp and another is a discharge lamp. CONSTITUTION:A four lamp type headlamp system is constituted so that two lamps, for example, a halogen lamp 1 as an incandescent lamp for a main beam and a discharge lamp 3 for a dimmer beam, make a pair. In this case, the halogen lamp 1 is controlled by means of a halogen lamp switching relay 5 as a second switch for performing ON-OFF operation of a power supply. In addition, the halogen lamp 1 is switched on in the case of ON of a beam change-over switch 25, and the discharge lamp 3 is switched on by discharge in the case of OFF of the switch 25. In other words, the beam change-over switch 25 constitutes a first switch for switching on the halogen lamp 1 by feeding. Furthermore, a control means is constituted for controlling ON-OFF of the halogen lamp switching relay 5 by means of a halogen lamp switching-on relay control transistor 29 of a discharge lamp control circuit 15 and a discharge control circuit 19 and the like.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a vehicle illumination lamp using a discharge lamp.

(Prior Art) As a conventional vehicle headlamp using a discharge lamp, there is, for example, one described in Japanese Patent Laid-Open No. 198046/1983.

That is, in this vehicle headlamp, a discharge lamp having a pair of dischargeable electrodes and a substance that becomes vapor and emits light when discharged is provided in a lamp housing, and an optical lens is provided on the front surface of this lamp housing, and an optical lens is provided on the rear surface of the lamp housing. The structure is such that each reflector is provided. The light emitted from a discharge lamp is a collection of light emitted when metal vapor, which is a luminescent substance, is excited to a high energy state and then returns to a low energy state. Therefore, incandescent lamps (including halogen lamps)
Compared to vehicle headlamps that use 2000 kW, it is possible to obtain more light with the same power consumption, making it possible to obtain a highly efficient lamp.

(Problems to be Solved by the Invention) However, vehicle headlights using such discharge lamps require a boost power supply circuit, a discharge starting circuit, a current control circuit, etc. to control the discharge lamp. Moreover, since these circuits need to be placed near the lamp, they have to be placed inside the engine compartment, which may reduce the reliability of the system.

On the other hand, in order to achieve high reliability, these circuits must have various types of water-resistant, heat-resistant, or vibration-resistant structures.
For example, when configuring a four-lamp headlamp system, the circuit becomes large and heavy, making it difficult to mount it on a vehicle.

Further, while the luminescent metal atoms or molecules must be sufficiently evaporated within the discharge lamp in order to stabilize the luminous intensity value, the degree of evaporation of the luminescent metal depends on the temperature within the discharge lamp. For this reason, even if you operate the lighting switch when the inside of the discharge lamp is cold, it will take time to reach the specified luminous intensity value, and in the case of beam switching, etc., the specified luminous intensity value will not be obtained immediately after the lighting operation. There was a fear that it would not be possible.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a vehicle headlamp that can improve reliability, be small and lightweight, and suppress a decrease in light intensity.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention provides a four-lamp type headlamp in which a main beam and a dimer beam are combined as a pair. One was constructed with an incandescent lamp and the other with a discharge lamp.

Also, a first switch for directly supplying power to the incandescent lamp, a second switch connected in parallel with the first switch and capable of supplying power to the incandescent lamp, and opening and closing of the second switch depending on the lighting state of the discharge lamp. The configuration includes a control means for controlling the

(Function) According to the above configuration, the main beam or dimer beam circuit in the four-lamp headlamp system circuit can be simplified by using an incandescent lamp circuit.

Even if a discharge lamp fails, switching to an incandescent lamp makes it possible to keep the incandescent lamp on.It is also possible to prevent all headlights from being turned off in the event of a system failure, thereby improving reliability. .

When switching lighting from an incandescent lamp to a discharge lamp, the incandescent lamp can be turned on depending on the state of decrease in light amount of the discharge lamp.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows a circuit diagram of one side of a vehicle headlamp according to an embodiment of the present invention.

This vehicle headlamp is a four-lamp type headlamp that is arranged on both left and right sides of the front of the vehicle, for example, a pair of halogen lamps 1 as incandescent lamps as the main beam and discharge lamps 3 as a dimer beam. It consists of a lighting system.

The halogen lamp 1 is configured to be controlled by a halogen lamp lighting relay 5, which serves as a second switch that turns on and off the power supply to the halogen lamp 1.

This halogen lamp lighting relay 5 is connected to a headlamp power supply relay 7 that switches on and off the power supply to the headlights, and this headlamp power supply relay 7 is connected to a battery 11 that serves as a power source via a power fuse 9. It is connected to the.

The headlamp power supply relay 7 includes a headlamp lighting switch 13.
instructions are now entered.

The discharge lamp 3 is configured to be controlled by a discharge lamp control circuit 15.

The discharge lamp control circuit 15 has a detailed structure as shown in FIG. That is, the discharge lamp control circuit 15 is the discharge lamp control circuit 1
7 and a discharge control circuit 19. The discharge circuit 17 is for discharging and lighting the discharge lamp 3, and the discharge control circuit 19 controls the discharge circuit 17 to control the discharge lamp 3 to at least a warm arc discharge state using a minute current and a lighting arc discharge state using a steady current. It is something. The discharge circuit 17 and one discharge control circuit are connected to relay contacts of the headlamp power supply relay 7 via power supply sections 21 and 23, respectively.

Instructions from the beam changeover switch 25 are input to the discharge lamp control circuit 15. An instruction input from the beam changeover switch 25 to the discharge lamp control circuit 15 is inputted to one discharge control circuit via a vehicle power supply prevention diode 27. When the beam changeover switch 25 is turned ON, the halogen lamp 1 is turned on, and the halogen lamp 1 is turned on.
The discharge lighting of the discharge lamp 3 is performed by the FF. Therefore, in this embodiment, the beam changeover switch 25 constitutes a first switch for supplying power to the halogen lamp 1 and turning it on.

Further, the discharge lamp control circuit 15 has a halogen lamp lighting relay control transistor 29, the collector terminal of which is connected to the excitation coil of the halogen lamp lighting relay 5. Further, the discharge lamp control circuit 15 includes a pull-up resistor 31 for beam switching signal input, and the beam switching switch 25.
and a diode 33 that directly controls the halogen lamp lighting relay 5. In this embodiment, the halogen lamp lighting relay control transistor 29, beam switching signal input pull-up resistor 31, halogen lamp direct control diode 33, and discharge control circuit 19 are control means for controlling opening and closing of the halogen lamp lighting relay 5. It consists of

The discharge circuit 17 includes a DC/ACC/type converter 35, a coupling capacitor 37, an LC resonance circuit 39, a discharge lamp current detection resistor 41, and a discharge lamp voltage detection capacitor 43.

The DC/ACC/equation converter 35 receives a set frequency input from the discharge control circuit 19.

The L-C resonance circuit 39 has an inductance. , capacitance C
6, and the capacitance of the voltage detection capacitor 43 is sufficiently larger than that of C8 (for example, 100
~1000 times). The detected voltage and detected current of the discharge lamp 3 are input to the discharge control circuit 19.

Next, the operation of the above embodiment will be explained.

First, the basic operation of discharge control will be explained.

By the discharge control circuit 19, the DC/ACC/formula 35
The conversion frequency f is set. As a result, the voltage Vsource is supplied to the LC resonance circuit 39 at the frequency F via the coupling capacitor 37.

This L-C resonant circuit 39 is constructed as shown in FIG.
When the discharge control circuit 19 is set to f-F, the power supply, Lo, Co
A very high voltage Vo (eg, 5KV to 20KV) is generated, which is determined by the internal resistance of the bone.

On the other hand, although the dielectric breakdown voltage of the discharge lamp 3 changes depending on the internal pressure, it is v. It is lower than that. Furthermore, when the discharge lamp 3 is in an insulated state, the voltage across the discharge lamp 3 is L
-C The voltage across the capacitor C6 of the resonant circuit 39 is approximately equal to the voltage across the capacitor C6.

Therefore, depending on the setting of f-Fo, the discharge lamp 3 immediately causes dielectric breakdown and spark discharge. During this spark discharge, all circuits inside the discharge lamp 3 are destroyed, resulting in an instantaneous short circuit, and the voltage across the discharge lamp 3 drops at once, but at the same time, thermoelectrons are self-excited and emitted from the cathode, causing an arc. It moves on to discharge.

When arc discharge is started, the discharge control circuit 19 detects the arc current via the discharge lamp current detection resistor 41 and controls f to a predetermined current value (for example, 0.2A to 1.OA).

Next, the operation of the entire circuit will be explained based on the control timing chart shown in FIG.

In FIG. 4, first, 1-1. When the headlight lighting switch 13 is turned on, the power supply fuse 9 is removed from the battery 11.
, the power is turned on via the headlight power supply relay 7%. When the beam changeover switch 25 is OFF, the discharge lamp control circuit 19 turns on the discharge lamp 3, which is a dimer beam, under the control described above.

Next, when the beam changeover switch 25 is turned on with txt and the beam changeover operation is performed, the excitation coil of the halogen lamp lighting relay 5 is connected to the power fuse 9 from the battery 11, the headlamp power supply relay 7, and the halogen lamp lighting relay. 5. Power is supplied through the path of the halogen lamp direct control diode 33 and the beam changeover switch 25, and the halogen lamp lighting relay 5 is turned on.
When the halogen lamp 1, which is the main beam, is turned on, the discharge control circuit 1 switches the beam changeover switch 25.
When ON is detected through the pull-up resistor 31 for beam switching signal input, the two halogen lamp lighting relay control transistors are immediately turned ON, but the discharge lamp 3, which is a dimer beam, continues to fish, and the halogen lamp 1 is turned on at 80%. The discharge lamp 3 is turned off at the time t, -t2+τ1, when the light amount reaches the light amount.

Here, τ is the turn-off delay time of the discharge lamp 3, for example, −
The discharge lamp 3 is turned off at a time of 0.1 to 0.2 seconds.

Such control makes it possible to suppress the instantaneous decrease in light intensity 4 when switching from the daimer beam to the main beam.

Next, at t 4, turn off the beam changeover switch 2 to switch from the main beam to the daimer beam.
Then, the discharge control circuit 19 immediately turns on the discharge lamp 3 via the discharge cycle 17.

At this time, the halogen lamp 1 is turned on and is turned on temporarily by controlling the two control transistors, until the discharge lamp 3 reaches 80% light intensity.

At the time of −14+τ2, the halogen lamp 1 is turned off.

Here, τ2 is the turn-off delay time of the halogen lamp 1, and is set to -0.1 to 1.0 seconds, for example.

Discharge lamp 3 takes time to reach the specified luminous intensity value when the temperature inside the discharge lamp is low, and it may also take time to start the initial discharge, so the initial lighting performance is unstable. However, by setting the turn-off delay time τ2 of the halogen lamp 1 as described above, it is possible to reliably suppress the instantaneous decrease in light intensity when switching from the main beam to the dimer beam.

Note that the turn-off delay time τ2 of the halogen lamp 1 may be changed by detecting the light emitting state from, for example, the tube internal temperature state or the initial current value of the discharge lamp 3, and changing accordingly.

Further, according to this embodiment, some functions of the power supply section 23, the discharge control circuit 19, the halogen lamp lighting relay control transistor 29, the diode 33 for direct control of the halogen lamp, the discharge circuit 17, etc. are malfunctioned, and the discharge lamp 3 Even if the halogen lamp 1 is not turned on or the halogen lamp 5 cannot be controlled, the halogen lamp 1 can be turned on immediately by turning on the beam changeover switch 25, thereby reliably preventing the headlights from turning off entirely. be able to.

[Effects of the Invention] As is clear from the above description, according to the configuration of the present invention, the size and weight of the four-lamp headlamp system circuit can be reduced.
Compared to a system in which all four lamps are discharge lamps, it is significantly smaller and lighter, making it easier to install in a vehicle. Even if a discharge lamp fails, it is possible to turn on the incandescent lamp by switching to an incandescent lamp, which prevents all headlights from turning off in the event of a system failure, improving reliability. .

Furthermore, it is possible to suppress a decrease in the amount of C light when switching lighting from an incandescent lamp to a discharge lamp.

[Brief explanation of drawings]

Fig. 1 is a circuit configuration diagram of two lights on one side of a vehicle lighting lamp according to an embodiment of the present invention, Fig. 2 is an enlarged view of main parts showing details of a discharge control circuit, and Fig. 3 is a diagram of a large resonance path. Figure 4 is a voltage frequency characteristic diagram and a timing chart for main and dimer switching control. ...Halogen lamp (incandescent lamp) 2...Discharge lamp 5...Halogen lamp lighting relay (second switch) 5...Beam selection switch (first switch)

Claims (2)

[Claims] (1) A four-lamp headlamp consisting of a main beam and a dimmer beam as a pair, for a vehicle, characterized in that one of the main beam and dimmer beam is an incandescent lamp and the other is an electric discharge lamp. Headlights. (2) a first switch that directly supplies power to the incandescent lamp; a second switch that is connected in parallel to the first switch and is capable of supplying power to the incandescent lamp; and opening and closing of the second switch that controls the lighting of the discharge lamp. The vehicle headlamp according to claim 1, further comprising a control means for controlling the headlamp accordingly.