JPH0390441A - Head lamp device for vehicle - Google Patents

Abstract

PURPOSE:To prevent the front visibility from deterioration by a method wherein first irradiating parts formed with discharge lamps for running beam irradiation and second irradiating parts for low beam irradiation are provided, and during switching from low beam irradiation to running beam irradiation, an amount of light emitted by the second irradiating part is gradually decreased for lighting OFF. CONSTITUTION:In a front headlamps 2 and 2' of an automobile, main beam irradiating parts 3 and 3' for running beam irradiation having a metal halide lamp being a discharge lamp and auxiliary beam irradiating parts 4 and 4' for low beam irradiation having halogen bulbs 12 and 12' are provided. A lighting control device is provided with a switching circuit 20 for switching running beams and low beam, a bulb lighting circuit 21, and a discharge lamp lightening circuit 23. The bulb lighting circuit 21 is formed in a manner to perform extinction control wherein quantities of light of the halogen bulbs 12 and 12' are gradually reduced for lighting OFF when irradiation of low beam is switched to irradiation of running beams by means of the switching circuit 20.

Description

DETAILED DESCRIPTION OF THE INVENTION The details of the vehicle headlamp device of the present invention will be explained in accordance with the following items.

A. Industrial field of application B1 Overview of the invention C9 Background technology 0 Problems to be solved by the invention [ito figure] E0 Means for solving the problem F. Examples [Figs. 1 to 9] F- 1. First embodiment [Figures 1 to 5] a. External appearance [
Fig. 1] b. Headlight unit [Fig. 2] C7 lighting circuit [Fig. 3, Fig. 4] c-1. Overall circuit configuration [! [Figure 3] c-2, Switching circuit C-3, Light bulb lighting circuit C-4, Discharge lamp lighting circuit d, Operation [Figure 5] F-2, Second embodiment [Figures 6 to 9] a0 lighting circuit [Fig. 6, Fig. 7 a-1, sub-beam irradiation section lighting circuit a-2, main beam irradiation section lighting circuit] Operation [Fig. 8, Fig. 9] Effect of the G0 invention (A. Industrial Application Field) The present invention relates to a novel vehicle headlamp device. Specifically, the vehicle headlight device includes a first irradiation section that irradiates a running beam and a second irradiation section that irradiates a passing beam, and uses a discharge lamp as a light source of the first irradiation section. An object of the present invention is to provide a novel vehicle headlamp device that does not cause a temporary decrease in the amount of irradiated light when switching from a low beam to a running beam.

(B. Summary of the Invention) The vehicle headlamp device of the present invention has a first irradiation section that irradiates a running beam and a second irradiation section that irradiates a passing beam, and the light source of the first irradiation section This is a vehicle headlamp device that uses a discharge lamp in the headlamp, and when switching from low-beam irradiation to driving beam irradiation, the light emission amount of the light source of the second irradiation part is gradually reduced and the light is turned off. By providing the light control means, a temporary decrease in the amount of irradiation light at the time of switching the irradiation beam is suppressed, and the visibility is prevented from deteriorating.

(C. Background Art) A so-called metal halide lamp, which has lower power consumption and higher efficiency than conventional halogen lamps, is attracting attention as a light source that can be used to make headlights thinner and more power efficient. This metal halide lamp has a pair of discharge electrodes inside its glass bulb, and is filled with a starting gas such as argon, mercury, and metal iodide, and when a high voltage is applied to the discharge electrode, the starting gas is activated. After the gas discharge, a mercury arc discharge occurs, and the heat generated at this time vaporizes metal iodide, which is dissociated within the mercury arc, emitting light with a spectrum unique to metal atoms.

(D. Problem to be solved by the invention) [Figure 10] By the way, this metal halide lamp does not brighten up instantly like a halogen bulb, and it takes several seconds to finally reach a stable brightness. , Irradiation] If the light source is simply switched when switching the beam, there is a problem in that the amount of light irradiated by the headlamp temporarily decreases and forward visibility deteriorates.

For example, when switching from lighting a halogen bulb for a low beam to a metal halide lamp for a running beam, a period T occurs in which the amount of light irradiated by the metal halide lamp is low, as shown in FIG. FIG. 10 is a graph schematically showing changes in the luminous flux of a light source (expressed as a percentage based on the rated luminous flux) over time, where the graph curve a is the luminous flux of a halogen bulb, and the graph curve is a metal halide bulb. It shows the luminous flux of the lamp.

(E. Means for Solving the Problems) Therefore, in order to solve the above-mentioned problems, the vehicle headlamp device of the present invention has a first irradiation section that irradiates a running beam, and a second irradiation section that irradiates a passing beam. irradiation part, and a discharge lamp is used as the light source of the first irradiation part, the vehicle headlamp device has a second irradiation part when switching from low beam irradiation to driving beam irradiation. A dimming control means is provided to gradually reduce the amount of light emitted from the light source of the section and turn off the light.

Therefore, according to the vehicle headlamp device of the present invention, when switching the irradiation beam from the passing beam to the driving beam,
Since dimming control is performed so that the amount of light irradiated by the second irradiation section gradually decreases and eventually reaches the off state, the amount of light irradiated by the headlights temporarily decreases and forward visibility deteriorates. There is no such thing as inviting.

(F. Embodiment) [FIGS. 1 to 9] Details of the vehicle headlamp device of the present invention will be explained according to each embodiment.

(F-1, First Embodiment) [Figs. 1 to 5] Figs. 1 to 5 show a first embodiment 1 of the vehicle headlamp device of the present invention.

(a, External appearance) [In Figure 1, 2.2' are headlamp units, and the main beam irradiation section 3.2' is provided for irradiation of the traveling beam.
3' and a sub-beam irradiation section 4.4' provided for irradiating the passing beam, and these headlamp units 2.2' are provided at positions near both left and right ends of the front of the vehicle. ing. These headlamp units 2.2' can be switched between a running beam and a passing beam by a lighting circuit which will be described later.

(b, Headlamp unit) [Figure 2] The headlamp unit 2.2' has a symmetrical structure, so below we will explain one headlamp located on the right side when viewed from the front of the vehicle. Only the unit 2 will be described, and the description of each part of the other headlamp unit 2' will be omitted by adding the reference numeral ``''' to each part of the headlamp unit 2.

Reference numeral 5 denotes a lamp body of the headlamp unit 2, and the lamp body 5 includes a main reflecting mirror portion 6 with an open front and a sub-reflecting mirror adjacent to the main reflecting mirror portion 6 from diagonally rear right and also having an open front. The front opening 8 of the lamp body 5 is slightly upward and slightly to the right (as viewed from the front) (slanted).

Attachment holes 9 are provided in the center of each rear part of the reflector part 6.7.
．． A metal halide lamp 11 is supported in one mounting hole 9, and a halogen light bulb 12 is supported in the other mounting hole 10.

Further, a lens installation groove 13 that opens substantially forward is formed in the opening 8 of the lamp body 5.

Reference numeral 14 denotes a lens made of transparent synthetic resin or glass, which includes a front surface portion 15 that faces substantially forward and slopes downward and to the right, and a peripheral wall portion 16 that protrudes substantially rearward from the periphery of the front surface portion 15. are integrally formed, and the peripheral wall portion 1
The rear end of the lamp body 6 is fitted into the installation groove 13 of the lamp body 5.

Thus, the main beam irradiation section 3 is composed of the main reflecting mirror section 6, the metal halide lamp 11, and the part of the lens 14 that corresponds to the main reflecting mirror section 6, and the sub-reflecting mirror section 7, the halogen bulb 12, and the lens 14 constitute the main beam irradiation section 3. 14, a portion corresponding to the sub-reflector section 7 constitutes the sub-beam irradiation section 4.

(c. Lighting Circuit) [FIGS. 3 and 4] Next, the configuration and operation of the lighting circuit 17 of the vehicle headlamp device 1 will be described.

(c-1, Overall circuit configuration) [Figure 3] Reference numeral 18 denotes a DC power supply, which is connected between power supply voltage input terminals 19 and 19'.

Reference numeral 20 denotes a switching circuit, which includes a lighting switch and a beam changeover switch, and is provided for switching between a running beam and a passing beam.

21 is a light bulb lighting circuit, halogen light bulb 12.12'
A halogen light bulb 12, 12' is connected in parallel between its output terminals 22, 22'.

23 is a discharge lamp lighting circuit, and its output terminal 24.24
Metal halide lamps 11 and 11' are connected in parallel between them.

(c-2, switching circuit) In the figure, 25 and 25' are power supply lines, the - side 25 is a positive line, and the other side 25' is a ground line.

26 is a lighting switch, one end of which is connected to the power supply voltage input terminal 19, and the other end connected to the beam changeover switch 2.
It is connected to the input side terminal 27a of No.7.

(c-3, light bulb lighting circuit) 28 is a two-relay, one end of which coil 28a is connected to one terminal 27b of the output terminals of the beam changeover switch 27, and the other end is grounded. A diode 29 is connected in parallel. And relay 2
Eight a-contact points 28b are provided on the positive line 25.

30 is a timer circuit, whose enable terminal is connected to the output side terminal 27b of the beam changeover switch 27 via a diode 31, and whose trigger terminal is connected to the positive line 25 via a diode 32; The time can be set using a variable resistor 33.

Reference numeral 34 denotes a drive circuit, which is provided to receive a signal from the timer circuit 30 and control the drive of a power transistor, which will be described later, and whose power supply terminal is connected to the diode 3.
Connected to the cathode of 2.

35 is a PNP type power transistor, and relay 2
In parallel to the a contact 28b of 8, that is, its emitter is connected to the positive line 25, and its collector is connected to the output terminal 22 via a diode 36 for preventing reverse current.
The base is connected to the output terminal of the drive circuit 34.

(c-4, discharge lamp lighting circuit) 37 is a DC boost circuit, for example, a chopper type DC-DC converter circuit that can vary the boost level by switching control of an active switch element is used, and the positive side Input terminal is beam selection switch 2
7, and the other input terminal is grounded. A voltage dividing resistor 38.38 for detecting the output voltage is connected between the output terminals of the DC booster circuit 37.
', and an output current detection resistor 39 is also provided on the output line on the ground side.

40 is a control circuit which generates a predetermined control signal according to the detection results from the voltage dividing resistors 38, 38' and the detection resistor 39, feeds this back to the DC booster circuit 37, and adjusts the level of its output voltage. provided for control.

41 is a high frequency booster circuit, which is provided after the DC booster circuit 37. After converting the DC voltage output by the DC booster circuit 37 into an AC voltage, the high frequency booster circuit 41 converts the DC voltage outputted by the DC booster circuit 37 into an AC voltage. This is a circuit for applying a high voltage to 11'. The current limiting circuit 42 is a series circuit of one winding 43a of the trigger transformer 43 and a capacitor 44, and the other winding 43b of the trigger transformer 43 is a series circuit.
is connected to an igniter starting circuit 45, which generates a starting pulse to trigger the metal halide lamp 11, 11'.

(d. Operation) [FIG. 5] The operation of the lighting circuit 17 described above is performed as follows. Furthermore, Figure 5 shows the metal halide lamp 11.1.
1', A graph diagram schematically showing the temporal change in the luminous flux of a halogen bulb 12.12', with the vertical axis centered on the luminous flux (expressed as a percentage of the rated luminous flux) and the horizontal axis plotting time. The period indicated by 'TOFFJ' in the figure is the main
This represents a non-lighting period in which both the light sources of the beam irradiation section 3.3' and the sub-beam irradiation section 4.4' are not lit.
The period indicated by 'TLJ represents the irradiation period of the passing beam, and r7. ” represents the irradiation period of the traveling beam. These symbols will be used with the same meaning in the second embodiment described later.

When irradiating a passing beam, the beam selection switch 27
The contact point is on the output side terminal 27b side, and when the lighting switch 26 is turned on, the relay 28 is turned on, and the a
Since the contacts 28b are closed, the halogen bulb 12.12
' is energized. Therefore, as shown by a graph curve 46 shown by a solid line in FIG. 5, the luminous flux of the halogen bulb 12, 12' rises instantaneously and stabilizes at the rated luminous flux. Note that at this time, the diode 31 is in an on state, the timer circuit 30 is not operating, and the power transistor 35 is off.

After that, connect the contact of the beam changeover switch 27 to the output side terminal 2.
When switched to the side 7c, the discharge lamp lighting circuit 23 is activated.

That is, the starting pulse generated by the igniter starting circuit 45 is superimposed on the AC voltage output from the high frequency booster circuit 41 to trigger the metal halide lamp 11, 11', and then the control circuit 40 activates the DC booster circuit. The output voltage of 37 is controlled to gradually decrease compared to the initial stage of lighting. Therefore, metal halide lamp 1
The luminous flux of 1.11' is shown in graph curve 47 (dashed line) in Figure 5.
As shown in FIG. 2, the rated luminous flux is reached several seconds after the beam changeover switch 27 is switched, and becomes approximately constant. That is, during the irradiation period TH of the traveling beam, only the main beam irradiation section 3.3' irradiates light.

By the way, regarding the light bulb lighting circuit 21, the relay 28 is turned off by switching to the running beam, and the a contact 28b is turned off.
However, at the same time, the diode 32 is turned on and the timer circuit 30 is activated, so the power transistor 35 is turned on by a signal sent to the power transistor 35 via the drive circuit 34, and then the power transistor 35 is turned on as time passes. Accordingly, the current flowing through the power transistor 35 is controlled to decrease. Therefore, halogen bulb 12
．． The luminous flux 12' gradually decreases accordingly, and after a time period defined by the variable resistor 33 of the timer circuit 30 has elapsed, the power transistor 35 is turned off and the halogen bulb 12, 12' is extinguished.

In this way, during the switching period (this is referred to as "Tc, 4") until the luminous flux of the metal halide lamp 11.11' reaches the rated value, the brightness of the halogen bulb 12.12' gradually decreases. Since the control is performed in such a manner that the amount of irradiated light is temporarily reduced by C when switching from the passing beam to the traveling beam, it is possible to avoid the situation.

(F''-2, Second Embodiment) [Figures 6 to 9] Figures 6 to 9 show a second embodiment IA of the vehicle headlamp device of the present invention. .

Note that the vehicle headlight device IA shown in this second embodiment is different from the vehicle headlight device 1 shown in the first embodiment, in that both the vehicle headlight device IA shown in the second embodiment are used as light sources for emitting a running beam and a passing beam. The only difference is that a metal halide lamp was used. Therefore, the description of the parts that are not different, such as the structure of the headlamp unit 2.2', will be omitted, and the explanation of the parts that are different from each part of the first embodiment 1 in the lighting circuit, and the parts that are not different will be omitted. Even if there is, the main parts will be explained, and the other parts will be given the same reference numerals as those used for the same parts in the first embodiment 1, and the explanation will be omitted. .

(a, lighting circuit) [Figures 6 and 7] In the figure, 48 and 48' are power supply lines, the negative side 48 is the positive line, and the other 48' is the ground line, and the light is lit on the positive line 48. A switch 26 is provided, one end of which is connected to the power supply voltage input terminal 19.

(a-1, lighting circuit for sub-beam irradiation section) 23A is a discharge lamp lighting circuit for the sub-beam irradiation section 4.4'.

Reference numeral 49 denotes a delayed return operation circuit, which not only turns on the metal halide lamp that emits the passing beam, but also controls the dimming control of the metal halide lamp as the light source of the passing beam when switching from the passing beam to the main beam. It is provided to take the time off and turn off the light after a predetermined period of time has elapsed.

In the delayed return operation circuit 49, an input terminal 27a of the beam changeover switch 27 is connected to a positive line 48, and one output terminal 27b is connected to a ground line 48' via an LED 50 and a capacitor 51. , the base of the emitter-grounded NPN transistor 52 is connected between the LED 50 and the capacitor 51 via the resistor 53, and the collector thereof is connected to the coil 54 of the relay 54.
It is connected to the positive line 48 via a. An a contact 54b of the relay 54 is provided on the positive line 48 between the coil 54a and a DC booster circuit to be described later. Note that 55 is a resistor inserted between the base and emitter of the transistor 52, and 56 is a diode connected in antiparallel to the coil 54a of the relay 54.

57 is a DC booster circuit, which includes an inductor 58 whose one end is connected to the a contact 54b of the relay 54;
N provided between the other end of 8 and the ground line 48'
It consists of a channel FET 59, a diode 60 whose anode is connected to the drain of the FET 59 on the positive line 48, and a capacitor 61 inserted between the cathode of the diode 60 and the ground line 48'. And, FET59 is a PWM
(Pulse Width Modulation) The switching operation is controlled by a control pulse sent from a control IC via a gate circuit.

Reference numeral 62 denotes a PWM control IC, and for example, as shown in FIG. It is connected between voltage dividing resistors 65 and 66, and a predetermined reference voltage is applied to the inverting input terminal.

Further, a current detection resistor 67 is provided on the ground side output line of the DC booster circuit 57, and the terminal voltage of the current detection resistor 67 is connected to the non-inverting input terminal 64a of the error amplifier 64 to the amplifier circuit 68 and the amplifier circuit. The signal is sent after passing through a low-pass filter 69 provided for reducing ripples in the output voltage of 68, and a predetermined reference voltage is applied to its inverting input terminal. The output terminals of these error amplifiers 63 and 64 are OR-connected to the minus input terminal of a PWM comparator 70, and the sawtooth wave from the oscillator 71 is input to the plus input terminal of the PWM comparator 70.

Reference numeral 72 denotes a rest period adjustment comparator, whose negative input terminal is connected to the control terminal 72a, and whose positive input terminal is connected to the output terminal of the oscillator 71.

The output terminals of the PWM comparator 70 and the idle period adjustment comparator 72 are each connected to the input terminal of an AND circuit 73, and the output signal of the AND circuit 73 is outputted as a control output via an output mode switching circuit 74 and a buffer 75. The signal is sent to a terminal 76.

77 is a gate circuit which receives a control pulse sent from the control output terminal 76 and controls F of the DC booster circuit 57.
A pulse signal is sent to the gate of ET59, and the FE759
This is provided to speed up the switching operation.

Reference numeral 78 denotes an integrating circuit, in which the non-inverting input terminal of the operational amplifier 79 is connected between the voltage dividing resistors 80 and 81 provided between the power supply voltage input terminals 19 and 19', and the inverting input terminal thereof is It is grounded via a resistor 82. and,
A capacitor 83 is inserted between the inverting input terminal and the output terminal, and a resistor 84 is connected in parallel to the capacitor 83.
and a phototransistor 85. Note that this phototransistor 85 is connected to the L of the delayed recovery operation circuit 49.
Together with ED50, it forms a photocoupler.

A diode 86 has its anode connected to the output terminal of the operational amplifier 79, and its cathode connected between the voltage dividing resistors 87 and 88. In addition, voltage dividing resistor 87
One end is connected to eight output terminals of a reference voltage circuit (not shown) provided in the PWM control IC 62, and a voltage dividing resistor 8
The terminal on the opposite resistance 87 side of 8 is grounded.

The control terminal 72a of the above-mentioned PWM control IC 82 is connected between the voltage dividing resistors 87 and 88, and a capacitor 90 is provided in parallel with the voltage dividing resistor 87.

Reference numeral 91 denotes a high frequency booster circuit, which is provided after the DC booster circuit 57, and its AC output is sent to output terminals 93 and 93' via a current limiting circuit 92.

Reference numerals 94 and 94' designate metal halide lamps, which are connected in parallel between output terminals 93 and 93', while 94 is supported in the mounting hole 10 of the headlamp unit 2;
The other end 94' is supported in the mounting hole 10' of the headlamp unit 2'.

95 is an igniter starting circuit.

(a-2, Lighting circuit of main beam irradiating section) Regarding the lighting circuit 23 of the main beam irradiating section 3.3', its DC booster circuit 37 (its configuration is similar to the DC booster circuit 37 described above). ) A delayed recovery operation circuit 96 is disposed in the preceding stage. The delayed return operation circuit 96 has the same configuration as the above-described delay return operation circuit 49, and its LED 97
The anode of is connected to the other output side terminal 27c of the beam changeover switch 27.

The control circuit 40 also includes a lighting circuit 23A of the sub-beam irradiation section.
Similarly, when signals corresponding to the voltage detected by the voltage dividing resistor 38, 38' and the output current of the DC booster circuit 37 by the detection resistor 39 are sent to the PWM control IC, the duty cycle is adjusted accordingly. A control pulse is sent to the DC booster circuit 37 to control its boost ratio.

When the light from the LED 97 to the phototransistor 99 of the integrating circuit 98 stops when switching the irradiation from the running beam to the passing beam, this causes the integrating circuit 98 to operate and the control circuit 40 to ignite the metal halide lamp 11. 11' dimming control is performed.

(b. Operation) [FIGS. 8 and 9] However, the operation of the lighting circuit described above is performed as follows.

During the irradiation period TL of the passing beam, when the lighting switch 26 is turned on, the metal halide lamps 94 and 94' start lighting as shown by the graph curve 100 shown by the solid line in FIG. 8, and after a few seconds, the rated luminous flux is reached. Brightness becomes stable.

That is, the contact point of the beam changeover switch 27 is connected to the output side terminal 27.
Since it is on the b side, the transistor 52 is turned on,
The relay 54 is turned on, its a contact 54b is closed, and the lighting operation is started. Then, a control pulse with a duty cycle corresponding to the output voltage and output current of the DC booster circuit 57 is generated from the PWM control IC 62, and this is fed back to the FET 59 of the DC booster circuit 57 via the gate circuit 77. The output voltage of the DC booster circuit 57 is controlled.

In other words, immediately after lighting, the lamp voltage is low and the output current of the DC booster circuit 57 is also small, so the duty cycle of the control pulse output from the PWM control IC 62 becomes the maximum value defined by the voltage dividing resistor 87.88. The output voltage of the DC booster circuit 57 is increased, and the metal halide lamps 94 and 94' are encouraged to emit light. As the luminous flux of the metal halide lamp 94,94' increases, the lamp voltage rises, and the output current of the DC booster circuit 57 increases, so that the duty of the control pulse output from the PWM control IC 62 increases. As the cycle decreases, the output voltage of the DC booster circuit 57 decreases accordingly. Finally, the output current of the DC booster circuit 57 is saturated to a steady level, and the luminous flux of the metal halide lamps 94, 94' settles to the rated luminous flux.

During this time, since the LED 50 continues to emit light, the integrating circuit 7
8 is not being performed, and the diode 86 is off.

After that, in order to switch from the passing beam to the running beam, connect the contact point of the beam changeover switch 27 to the other output side terminal 2.
7c side, the LED 50 turns off, the integration circuit 78 starts integrating, and the output voltage of the operational amplifier 79 increases. When the diode 86 turns on, this output voltage is applied to the control terminal 72a of the PWM control IC 62. and its potential increases. Therefore, the duty cycle of the control pulse is determined by the duty cycle of the output signal of the rest period adjustment comparator 72, regardless of the output voltage of the error amplifiers 63 and 64, and as the potential of the control terminal 72a increases, Duty cycle decreases. Therefore, the output voltage of the DC booster circuit 57 decreases accordingly, and the luminous flux of the metal halide lamp 94,94' also decreases, and by the time the duty cycle of the control pulse approaches 0, the capacitor 51, the resistor The time constant circuit composed of 53 and 55 turns off the transistor 52, turns off the relay 54, and turns off the metal halide lamps 94 and 94'.

FIG. 9 is a time chart at the time of this switching, in which 5W27 is the state of the contact of the beam changeover switch 27, R3'54 is the operation of the relay 54, V721 is the potential of the control terminal 72a, and L is the metal halide lamp 94.
．． 94' luminous fluxes are respectively represented.

On the other hand, when the contact of the beam changeover switch 27 is switched, the lighting circuit 23 is activated, and the metal halide lamp 11.11
' starts to light up, and the graph curve 1 shown by the broken line in Fig.
The luminous flux rises as shown in 01, reaches the rated luminous flux after a few seconds, and the brightness stabilizes.

In this way, the metal halide lamp 11 for the traveling beam.
During the switching period TcN until 11' reaches a predetermined brightness, the metal halide lamp 94.94 for the passing beam
Since control is performed so that the light gradually decreases, forward visibility will not deteriorate due to a temporary decrease in the amount of irradiated light.

After that, when switching to the low beam again, the lighting circuit 2
The LED 97 of No. 3 goes out, the integrating circuit 98 performs an integrating operation, and the metal halide lamps 11 and 11' gradually dim. And metal halide lamp 11.11
By the time ' is turned off, the luminous flux of the metal halide lamps 94 and 94' for the passing beam has reached the rated value, so there is no temporary decrease in the amount of irradiated light even during this switching.

(G. Effects of the Invention) As is clear from the above description, the vehicle headlamp device of the present invention has a first irradiation section that irradiates a running beam and a second irradiation section that irradiates a passing beam. A vehicular headlamp device in which a discharge lamp is used as the light source of the first irradiation section, the light source of the second irradiation section being switched from low beam irradiation to driving beam irradiation. The light emitting device is characterized by being provided with a dimming control means that gradually reduces the amount of light emitted by the light and turns off the light.

Therefore, according to the vehicle headlamp device of the present invention, when switching the irradiation beam from the passing beam to the driving beam,
Since dimming control is performed so that the amount of light irradiated by the second irradiation section gradually decreases and eventually turns off, - the amount of light irradiated by the headlights temporarily decreases and forward visibility deteriorates. There is no such thing as inviting.

The above-mentioned embodiments are merely examples of the vehicle headlight device according to the present invention, and the technical scope of the vehicle headlight device of the present invention is limited only to such devices. However, it is possible to construct a dimming control means according to the circuit configuration of the lighting circuit of the halogen bulb or metal halide lamp. For example, it is possible to vary the frequency of the AC voltage applied to the metal halide lamp. In the case of a lighting circuit that controls light emission based on the illumination beam, it is sufficient to gradually reduce the frequency of the AC voltage to turn off the light when switching the irradiation beam, without departing from the technical scope of the vehicle headlamp device of the present invention. It is possible to carry out the invention in various ways.

[Brief explanation of drawings]

1 to 5 show a first embodiment of the vehicle headlight device of the present invention, and FIG. 1 is a schematic front view showing the vehicle headlight device installed on a vehicle. , Figure 2 is a horizontal sectional view of the headlamp unit, Figure 3 is a circuit block diagram showing the overall configuration of the lighting circuit, Figure 4 is a circuit block diagram, and Figure 5 is a circuit block diagram showing the overall configuration of the lighting circuit.
The figure is a graph diagram for explaining the illumination state of the headlights.
9 to 9 show a second embodiment of the vehicle headlamp device of the present invention, FIG. 6 is a circuit block diagram, and FIG.
A circuit block diagram showing the circuit configuration of the WMIJ official IC, FIG. 8 is a graph diagram for explaining the irradiation state of the headlight, and FIG. 9 is a time chart diagram for explaining the operation at the time of beam switching. FIG. 10 is a graph diagram for explaining the problem. Explanation of symbols 1...Vehicle headlamp device, 3.3'...First irradiation part, 4.4'...Second irradiation part, 11.11'...Discharge lamp, 12.12'... Incandescent light bulb, 21.30.34.35... Dimming control means, Vehicle headlight device, 3A. 50. 62, - Dimming control substage, 94, 4 - Discharge lamp, Applicant Koito Manufacturing Co., Ltd. 1 - Vehicle headlight device 4.4' Second head schematic front view Figure 1 62. /1IIJ Rabbit Means 2 Figure 7 Time-8-Yard Diagram (Second Tiger Abandonment) Figure 9

Claims (3)

[Claims] (1) A vehicle headlamp device having a first irradiation section that irradiates a running beam and a second irradiation section that irradiates a passing beam, and in which a discharge lamp is used as the light source of the first irradiation section. For a vehicle, characterized in that it is provided with a dimming control means that gradually reduces the amount of light emitted from the light source of the second irradiation part and turns off the light when switching from irradiation of a passing beam to irradiation of a running beam. headlight device (2) A vehicle headlamp device according to claim 1, characterized in that the light source of the second irradiation section is an incandescent light bulb. (3) A vehicle headlamp device according to claim 1, characterized in that the light source of the second irradiation section is a discharge lamp.