JP2589662Y2 - Headlight lighting device for vehicles - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION This invention is for a vehicle that uses a high-pressure discharge lamp such as a metal halide lamp as a light source and turns on the high-pressure discharge lamp at a high frequency using a converter for boosting a DC voltage and an inverter for high-frequency conversion. The present invention relates to a headlight lighting device.

[0002]

2. Description of the Related Art Conventionally, incandescent lamps (eg, halogen lamps) have been used as a light source for headlights of vehicles. However, incandescent lamps have disadvantages such as low luminous efficiency and short life. was there. On the other hand, recently, research and development of a device using a high-pressure discharge lamp (for example, a metal halide lamp or the like), which has a high luminous efficiency and is easy to miniaturize, as a light source of a headlight are being advanced.

[0003] By the way, a headlight of a vehicle is required to be instantaneously lit and instantaneously luminous flux rising. However, high pressure discharge lamps are generally difficult to start. In order to use a high-pressure discharge lamp having such properties as a light source of a vehicle headlamp, it is necessary to provide a configuration that can be turned on instantaneously. Therefore, in a vehicle headlamp lighting device, an igniter (Starting circuit) using more than 10 k
By applying a high-voltage pulse voltage of about V to the high-pressure discharge lamp, it is intended to realize instantaneous lighting of the high-pressure discharge lamp.

[0004] However, since such a high-voltage pulse is applied, an electric shock accident occurs at the time of lamp replacement or the like, or a gasoline gas which has been gasified at the time of a vehicle accident occurs, as compared with a conventional incandescent lamp. When a high-voltage pulse is generated in the above, there is a risk that the gasoline gas may ignite and explode, which is a problem in terms of safety. On the contrary,
In order to prevent electric shock when replacing the bulb (light source unit) of the high pressure discharge lamp, the one with the interlock function and the function to detect disconnection when the lens is broken such as in an accident and to automatically stop the operation of the lighting circuit have already been provided. It has been proposed.
657).

[0005]

[Problem to be solved by the invention] In the above proposed example,
For example, a configuration in which conductive paths are distributed and arranged on one of the front surface and the rear surface of the lens, and a current is supplied to the conductive path to detect an increase in the resistance value of the conductive path due to damage to the lens, and the power supply to the high-pressure discharge lamp is stopped. In addition to detecting the fact that the lens has been completely broken in an accident or the like, it not only stops the energization of the high-pressure discharge lamp but also hits the lens while the vehicle is running. Even when cracks, chips or the like occur, the power supply to the high-pressure discharge lamp is stopped.

However, to the extent that the lens is cracked, chipped, or the like, there is almost no abnormality in the high-pressure discharge lamp as the internal light source. There is no major problem with the light distribution of the lens, and it is considered that there is no particular problem even if the lens is continuously used thereafter. As described above, in the conventional vehicle headlamp lighting device, the conductive path is provided in the lens, and the power supply to the high-pressure discharge lamp is stopped by increasing the resistance value due to the damage of the lens. In order to restart the lens, it is necessary to replace the lens, and a lens that has not yet lost its original function and can be used sufficiently, such as prevention of electric shock, prevention of ignition of fuel gas by high voltage pulse voltage, etc. It is considered wasteful to replace the conductive path provided due to an increase in the resistance value of the conductive path provided from the viewpoint of ensuring safety. Moreover, lens replacement is more difficult and expensive than lamp replacement, which is a major problem.

Accordingly, an object of the present invention is to provide a headlight lighting device for a vehicle which can easily and inexpensively secure safety aspects such as prevention of electric shock and prevention of ignition of vaporized fuel by high voltage pulse voltage. It is to provide.

[0008]

A vehicle headlamp lighting device according to the present invention comprises a base having an arc tube attached thereto, a protection tube having distribution paths formed on at least one of an outer surface and an inner surface, and a light emitting tube. A high-pressure discharge lamp mounted in a state surrounding the tube, a lighting circuit for supplying lighting power to the arc tube, and detecting an increase in the resistance value of the conductive path due to breakage of the protective tube by energizing the conductive path. And a control unit for forcibly stopping the operation of the lighting circuit in response to the output of the detection unit.

[0009]

According to the structure of the present invention, when the protection tube adjacent to the arc tube is damaged and the resistance value of the conductive path increases, the detection unit detects this and sends a signal to the control unit. As a result, the control unit forcibly stops the operation of the lighting circuit, stops power supply to the arc tube, prevents electric shock at the time of lamp replacement, etc. Prevents inflammation and ensures safety.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention has been made in view of the fact that a vehicle headlight is constructed as follows. Recent automobiles have been reduced in weight, and the headlights are often made of plastics and the like in addition to metal. Since these plastics are easily deteriorated by ultraviolet rays, it is necessary to block ultraviolet rays emitted from the discharge lamp. In addition, when the arc tube is directly touched by hand, the life of the arc tube is likely to be shortened.

As described above, there is a discharge lamp in which a protective tube (outer bulb) is provided outside the arc tube. In such a type of discharge lamp, a conductive path for damage detection is formed on at least one of the inner surface and the outer surface of the protective tube, and a predetermined voltage is applied to the conductive path to detect a current flowing through the conductive path. When the value is less than the predetermined value, that is, when the resistance value of the conductive path exceeds the predetermined value, the power supply to the discharge lamp is stopped to prevent electric shock at the time of lamp replacement or the like. In addition, in the event of an accident or the like, it is possible to prevent ignition of vaporized fuel due to the high-voltage pulse voltage, thereby ensuring safety.

After the protection tube is broken, the lighting can be restarted by replacing only the protection tube or by replacing both the arc tube and the protection tube. Hereinafter, examples will be specifically described. A first embodiment of the present invention will be described with reference to FIGS. In this vehicle headlight lighting device, as shown in FIG. 1, a high-pressure discharge lamp 1 is mounted on a rear opening of a lamp body 2 having a lens portion 2a on a front surface. The high-pressure discharge lamp 1 has a base 1b to which an arc tube 1a is attached.
A protective tube 1c having conductive paths (not shown) formed on at least one of the outer surface and the inner surface, and an arc tube 1a
Are mounted in a state of being closely enclosed. The protection tube 1c is
The base 1b to which the arc tube 1a is attached may be configured to be detachable, or the base 1b and the protection tube 1c may be integrated so that the protection tube 1c cannot be removed.

The arc tube 1a is connected to two lighting power lines 1d whose both lead wires are drawn rearward from the base 1b within the base 1b. In addition, protection tube 1c
The ends of the conductive paths formed on at least one of the outer surface and the inner surface are respectively connected to two protection tube breakage detection signal lines 1e drawn rearward from the base 1b in the base 1b.

On the other hand, the lighting power is supplied to the high-pressure discharge lamp 1 and the high-pressure discharge lamp 1
The lighting device 3 that stops supplying power to the power supply is configured as follows. That is, the voltage of the DC power supply 4 (12 V or 24 V) is boosted to a DC voltage of about 300 V or more by the converter 5, the DC power supplied from the converter 5 is converted into high frequency power by the inverter 6, and light is emitted through the lighting power line 1 d. Supply to tube 1a. The starting is performed by applying a starting high-voltage pulse voltage of, for example, about 15 kV to the arc tube 1 a by the starting circuit 7.

The detecting section 8 is connected to both ends of a conductive path provided in the protective tube 1c via a protective tube damage detection signal line 1e, and applies a predetermined voltage between both ends of the conductive path provided in the protective tube 1c. When the current flowing through the conductive path becomes less than a predetermined value due to breakage of the protective tube 1c, that is, when the resistance value of the conductive path becomes more than a predetermined value, the protective tube is damaged. Generate a detection signal.

The control section 9 forcibly stops the operations of the converter 5, the inverter 6, and the starting circuit 7 in response to the protection tube breakage detection signal from the detection section 8 to stop the power supply to the arc tube 1a. Prevent electric shock accidents when replacing lamps and prevent ignition of vaporized fuel to ensure safety. In this case, the lighting circuit 1 in which the converter 5, the inverter 6 and the starting circuit 7 supply lighting power to the arc tube 1a
0.

The protection tube breakage detection signal of the detection unit 8 is also supplied to the display unit 11 so that when the protection tube 1c is damaged, it is displayed. The display unit 11 may be omitted. FIG. 2 shows an example of a conductive path pattern formed on the inner surface or the outer surface of the protective tube 1c. In this example, the linear conductive paths 12 are distributed and formed in a zigzag running state over the entire circumference of the protective tube 1c. ing. Therefore, even if any part of the protection tube 1c is damaged, the conductive path 12
Is broken or somewhere near that, the resistance value of the conductive path 12 increases, and the detection unit 8 detects an increase in the resistance value.

According to the vehicular headlamp lighting device of this embodiment, when the protective tube 1c surrounding the arc tube is broken, the power supply to the arc tube 1a is stopped, thereby preventing electric shock at the time of lamp replacement. In addition, it is possible to prevent ignition of the vaporized fuel by the high-voltage pulse when an accident occurs. Further, even if the lens portion 2a existing in front of the high-pressure discharge lamp 1 is cracked or chipped, the arc tube 1a
The power supply to the lamp is not stopped, and unnecessary turning off of the high-pressure discharge lamp 1 does not occur, and unnecessary lens replacement, that is, lamp replacement, can be stopped. Therefore, it is possible to easily and inexpensively secure safety aspects such as prevention of electric shock and prevention of ignition of vaporized fuel by high-voltage pulse voltage.

Further, since the protective tube 1c is attached to the base 1b to which the arc tube 1a is attached, wiring to the conductive path 12 can be performed together with wiring to the arc tube 1a, and a structure for detecting damage is provided. Is easy. A second embodiment of the present invention will be described with reference to FIG. In the vehicle headlamp lighting device, the pattern of the conductive paths 13 provided in the protection tube 1c is formed in a net shape and distributed over the entire circumference of the protection tube 1c. Therefore, even if any part of the protection tube 1c is damaged,
Disconnection or a state close to the disconnection occurs somewhere in the conductive path 13, the resistance value of the conductive path 13 increases, and the detection unit 8 detects an increase in the resistance value. Further, when the conductive path 13 is formed in a mesh shape in this manner, the conductive path 13 has an excellent electromagnetic shielding function, and radiation of high-frequency noise when the high-pressure discharge lamp 1 is lit at high frequency can be minimized. Therefore, malfunction of electronic devices such as an engine control computer installed near the high-pressure discharge lamp 1 can be effectively prevented.

The construction, operation and effect other than the above are the same as those of the first
This is the same as the embodiment. FIG. 4 shows a third embodiment of the present invention.
It will be described based on. In this vehicle headlamp lighting device, the voltage applied to the conductive path for detecting the breakage of the protection tube 1c is constantly increased, so that the power loss increases. Therefore, as shown in FIG. To the conductive path
As shown in (b), the current is intermittently supplied to reduce power loss due to damage detection.
In FIG. 4B, a period T ₁ indicates a normal operation period,
Period T ₂ are protective tube 1c shows a corrupted period, the power supply to the period T ₂ in the light emitting tube 1a is stopped.

The construction, operation and effects other than those described above are the same as those of the first embodiment. The frequency at which the voltage is intermittently applied is in the range of about several Hz to several tens of kHz, and the smaller the duty ratio, the smaller the power loss.

[0022]

According to the headlamp lighting device for a vehicle of the present invention, power supply to the light emitting tube is stopped when the protective tube surrounding the light emitting tube is broken, thereby preventing electric shock at the time of lamp replacement. In addition, it is possible to prevent ignition of the vaporized fuel by the high-voltage pulse when an accident occurs. Also, even if the lens existing in front of the high pressure discharge lamp is cracked or chipped, the power supply to the arc tube is not stopped,
Unnecessary turning off of the high-pressure discharge lamp does not occur, and unnecessary lens replacement can be stopped. Therefore, it is possible to easily and inexpensively secure safety aspects such as prevention of electric shock and prevention of ignition of vaporized fuel by high-voltage pulse voltage.

Furthermore, since the protective tube is attached to the base on which the arc tube is attached, wiring to the conductive path can be performed together with wiring to the arc tube, and the structure for damage detection is simple.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram showing a configuration of a vehicle headlamp lighting device according to a first embodiment of the present invention.

FIG. 2 is a schematic view showing an example of a conductive path pattern formed on an inner surface or an outer surface of a protective tube of a high-pressure discharge lamp.

FIG. 3 is a schematic diagram showing an example of a conductive path pattern formed on an inner surface or an outer surface of a protection tube in a vehicle headlamp lighting device according to a second embodiment of the present invention.

FIG. 4 is a waveform diagram of a voltage applied to a conductive path provided in a protection tube and a current flowing through the conductive path in the vehicle headlamp lighting device according to the third embodiment of the present invention.

[Description of Signs] 1 High-pressure discharge lamp 1a Arc tube 1b Base 1c Protective tube 2 Lamp body 2a Lens unit 3 Lighting device 4 DC power supply 5 Converter 6 Inverter 7 Starting circuit 8 Detecting unit 9 Control unit 10 Lighting circuit 11 Display unit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ identification code FIF21V 25/04 B60Q 1/04 E (58) Investigated field (Int.Cl. ⁶ , DB name) H05B 41/18 H05B 41 / 18 310 F21M 3/02 H02H 11/00 B60Q 1/04 F21V 25/04

Claims (1)

(57) [Scope of request for utility model registration] 1. A high-pressure discharge lamp in which a protective tube having conductive paths formed on at least one of an outer surface and an inner surface is attached to a base on which an arc tube is attached so as to surround the arc tube, and the arc tube. A lighting circuit for supplying lighting power to the power supply; a detection unit for supplying an electric current to the conductive path to detect an increase in the resistance value of the conductive path due to breakage of the protective tube; and the lighting in response to an output of the detection unit. A vehicle headlamp lighting device comprising: a control unit for forcibly stopping an operation of a circuit.