JPH05225803A - Defogging method for lighting fixture for vehicle - Google Patents

Abstract

(57) [Summary] [Purpose] In conventional vehicle lamps such as headlamps, ventilation holes for relaxing internal pressure changes were opened in the engine room, so the lens was rapidly cooled during snowfall, car washing, etc. In such a state, the inside of the engine room is also in a high humidity state, and sucking this high humidity air causes a problem that the headlamp becomes cloudy. [Structure] The ventilation hole 5 of the headlamp 1 is opened in the vehicle interior 12, and the air in the vehicle interior 12 that is kept in the most dry state in the automobile 10 is sucked in.
The headlamp lamp chamber can be kept in a dry state without being affected by external conditions such as rainy weather or car washing, thereby preventing the front lens 2 from being fogged even in a rapidly cooled state. Solve.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicular lamp such as a headlamp, and more particularly, when the front lens of the vehicular lamp is rapidly cooled, such as during cold weather or when washing a car.
The present invention relates to a method for preventing dew condensation on the front lens.

[0002]

2. Description of the Related Art FIG. 3 shows an example of a headlamp 90 of a conventional vehicle lamp of this type. A light source 91 having a large amount of heat, such as a halogen bulb, is disposed in the lamp so that it can be turned on. At times, the air thermally expands and the pressure inside the lamp becomes high, causing problems such as deformation of the housing 92 and peeling off the adhesive of the front lens 93. Further, when the lighting is turned off, the inside of the lamp becomes negative pressure and flooding occurs. Therefore, a ventilation hole 92a having drip-proof performance is provided on the back surface of the housing 92 to alleviate the pressure fluctuation. A drain hole 92b is usually provided at the lowest position of the housing 92 in preparation for water from the ventilation hole 92a.

[0003]

However, in the above-mentioned conventional headlamp 90, the above-mentioned problems can be certainly prevented, but the ventilation hole 92a and the drain hole 92b are provided in the automobile 10. Since the opening is formed in the engine room 11, when the front lens 93 is cooled in a state where the humidity in the engine room 11 is extremely high, for example, when washing a car, the high suctioned from the inside of the engine room 11 is caused. The humidity of air causes dew condensation on the back surface of the front lens 93 to cause temporary fogging, which causes a problem that the user feels uncomfortable.

As a solution to this point, conventionally, a method has been proposed in which the thickness of the front lens 93 is increased to improve the heat insulating property to prevent cool air on the front surface from reaching the rear surface of the lens. From the surface or design side to the front lens 93
The amount of increase in the wall thickness naturally occurs, and as a result, the above-mentioned problems are reduced to some extent, which cannot be an essential solution.

[0005]

As a concrete means for solving the above-mentioned conventional problems, the present invention is provided with a ventilation hole for alleviating fluctuations in the lamp internal pressure caused by turning on and off a light source. In the vehicular lamp including the above, the ventilation hole is extended by a tube and is opened to the passenger compartment of the automobile, and breathing the air in the passenger compartment causes the occurrence of dew condensation when the front lens of the vehicle lamp is rapidly cooled. By providing an anti-fog method for a vehicle lamp, which is characterized by preventing the above, the above-mentioned conventional problems are solved.

[0006]

EXAMPLES The present invention will now be described in detail based on the examples shown in the drawings. FIG. 1 shows an example of a headlamp 1 as a first embodiment of an anti-fog method for a vehicle lamp according to the present invention.
In FIG. 1, the headlamp 1 is shown attached to a vehicle 10.

Here, the headlamp 1 has a light source 4 such as a halogen bulb, which generates a large amount of heat, in a lamp chamber formed by a front lens 2 and a housing 3. In order to alleviate the change, the ventilation hole 5 is provided at an appropriate position such as the back surface of the housing 3 and has the same structure as the headlamp 1 of the conventional example.

However, according to the present invention, the ventilation holes 5
Is not opened in the engine room 11 of the automobile 10 as in the conventional example, and by connecting the pipe 6 formed of, for example, metal or relatively hard resin to the ventilation hole 5. The passenger compartment is extended to the inside of the passenger compartment 12, and the passenger compartment is opened.

In the present invention, the headlamp 1 is used.
Since there is no possibility of water being flooded into the lamp, the conventionally provided drain hole is not provided, and the headlamp 1 is located at a position other than the vehicle compartment 12 opened through the pipe 6, for example, the engine room. For 11 and the like, the structure is completely sealed.

Next, the operation and effect of the present invention having the above-described structure will be described. Since the ventilation hole 5 is opened in the passenger compartment 12, the inside of the headlamp 1 is turned on by turning on and off the light source 4. When breathing in the lamp room, especially during inhalation immediately after shifting from the lighting state to the extinguishing state, even if outside air is in a high humidity state such as rainy weather, air conditioning is performed and the vehicle interior is adjusted to a low humidity state The air of 12 is sucked, and as a result, the inside of the headlamp 1 is always kept in a low humidity state.

Further, even in a state where the front lens 2 surface is rapidly cooled due to a car wash or the like, the headlamp 1 does not suck in the air in the engine room 11 which is humid due to the car wash, and the occupant lives For this reason, the air in the vehicle interior 12 is made waterproof so that the humidity does not rise so much due to a car wash. Therefore, the head lamp 1 does not become extremely humid.

This means that the inside of the headlamp 1 is always kept in a relatively low humidity state, and even when the front lens 2 surface is rapidly cooled such as snowfall or car washing, the rear surface of the front lens 2 is cooled. This will prevent condensation from forming on the surface. At the same time, a drainage hole is not required and the structure is hermetically sealed in a high humidity place such as the engine room 11, so that the above-mentioned operation is further ensured.

FIG. 2 is also a second embodiment of the present invention, and the first embodiment described above exclusively utilizes the heat generation and cooling of the light source 4 and the breathing action of the headlamp 1 itself makes the passenger compartment. In contrast to the purpose of inhaling the dry air inside 12, the second embodiment is intended to forcibly introduce relatively dry air into the headlamp 1.

In order to achieve the above-mentioned object, one of the rear surfaces of the housing 3 of the headlamp 1 is opened in the vehicle interior 12 by the pipe 6 in exactly the same manner as described in the first embodiment. In addition to the ventilation hole 5, another one of the ventilation holes 7 is provided, and the other one of the ventilation holes 7 is a pipe 8 having a similar structure, which has a pressure slightly higher than the atmospheric pressure, such as a blowing passage of the air conditioner 13. Is connected to the positive pressure portion 13a.

With the above structure, the dehumidified air of the air conditioner 13 is always introduced into the interior of the head lamp 1 from the other one ventilation hole, and this air is supplied to the one ventilation hole. It will be returned to the passenger compartment via the vehicle 5.
Therefore, relatively dry air constantly circulates inside the lamp chamber of the headlamp 1, so that not only is the humidity kept low, but even if inundation occurs, it can be dried quickly. Become.

The operations and effects other than those described above are exactly the same as those of the previous embodiment, and therefore detailed description thereof is omitted here. In addition, although the above-described embodiments have been described by taking headlamps as examples, the present invention is not limited to headlamps, and can also be implemented in vehicular lamps such as tail lamps. It may be opened in a trunk room that is almost as waterproof as the passenger compartment 12.

[0017]

As described above, according to the present invention, the ventilation hole of a vehicle lamp such as a headlamp is opened in the vehicle interior to suck in the air in the vehicle interior, which is the most dry state of the vehicle. Thus, the interior of the vehicular lamp can be made dry without being affected by external conditions such as rainy weather or car washing, whereby the front lens surface is rapidly cooled, for example, during snowfall or car washing. Even under the condition, it is possible to prevent the user from feeling uncomfortable as it is unlikely to cause dew condensation inside, and to exert an excellent effect on quality improvement.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a first embodiment of an antifogging method for a vehicle lighting device according to the present invention.

FIG. 2 is a schematic cross-sectional view showing a second embodiment of the method for preventing fog of a vehicular lamp according to the present invention.

FIG. 3 is a schematic sectional view showing a conventional example.

[Explanation of symbols]

 1 ... Headlamp 2 ... Front lens 3 ... Housing 4 ... Light source 5, 7 ... Ventilation hole 6, 8 ... Pipe 10 ... Car 11 ... Engine room 12 ... Car room

Claims (2)

[Claims] 1. A vehicular lamp having a ventilation hole for reducing fluctuations in pressure inside the lamp caused by turning on and off a light source, wherein the ventilation hole is a tube that extends into a passenger compartment of an automobile. A method for defrosting a vehicular lamp, comprising preventing the occurrence of dew condensation when the front lens of the vehicular lamp is rapidly cooled by breathing the air in the vehicular lamp. 2. The ventilation holes are provided at two positions of the vehicle lamp, one of the ventilation holes is extended to an interior of an automobile and opened, and the other of the ventilation holes is used as a positive pressure portion of an air conditioner. A method for defrosting a vehicular lamp, comprising opening and breathing air from the vehicle compartment or an air conditioner to prevent dew condensation when the front lens of the vehicular lamp is rapidly cooled.