JPH0568006U - Vehicle lighting - Google Patents

Abstract

(57) [Abstract] [Purpose] In a conventional vehicle lamp, when the temperature difference between the interior of the lamp heated by a light bulb and the outside air is large, the moisture that condenses on the inner wall surface of the front lens becomes water drops and becomes cloudy. As a result, the illuminance and the light distribution characteristics are deteriorated and the user feels uncomfortable. [Structure] The front lens 2 has a front lens 2 having a resin anti-fogging film 7 formed on the inner wall surface thereof.
Even in a state in which a significant temperature difference occurs between the inner and outer surfaces of the inner wall surface and dew condensation occurs on the inner wall surface, the water content adhering to the inner wall surface is diffused into a water film having a uniform thickness due to the hydrophilicity of the antifogging film 7 to form a cloud. It is possible to solve the problem by preventing the occurrence of the occurrence of the occurrence of the deterioration of the performance of the vehicular lamp 1 such as a decrease in the illuminance and a poor light distribution, and without giving the user a feeling of discomfort.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a vehicular lamp such as a headlight or a taillight, and more particularly to improving anti-fog performance of the vehicular lamp.

[0002]

[Prior Art]

 FIG. 3 shows an example of a conventional headlamp 90 of this type of vehicular lamp. The headlamp 90 includes a housing 91 and a front lens 92, each of which is made of resin, and is substantially closed. A lamp chamber 93 is formed in the lamp chamber 93, and a reflecting mirror 94, a halogen bulb 95 and the like are housed inside the lamp chamber 93.

[0003]

[Problems to be solved by the device]

 However, in the above-described conventional headlamp 90, the temperature of the air in the lamp chamber 93 rises due to the lighting of the halogen bulb 95, and the moisture in the lamp chamber 93 evaporates, so that the ambient temperature in summer, winter, etc. Regardless of the condition, the humidity is relatively high. At this time, if the vehicle is traveling in an environment where the outside temperature is low in winter, the front lens 92 is cooled by the traveling wind, and as a result, dew-like dew condensation occurs on the inner wall surface of the front lens 92 and becomes cloudy. In addition to the problems in performance such as the deterioration of the light distribution characteristics and the decrease in illuminance, there is also a problem that the user feels uncomfortable and the commercialability is deteriorated, and it is an issue to solve these problems. It was supposed to be.

[0004]

[Means for Solving the Problems]

 As a concrete means for solving the above-mentioned conventional problems, the present invention provides a vehicular lamp in which a front lens is made of a synthetic resin, and a synthetic resin-based anti-fog coating is formed on an inner wall surface of the front lens. The present invention solves the conventional problems by providing a vehicular lamp characterized in that it does not cause fog on the inner wall side of the front lens.

[0005]

【Example】

 Next, the present invention will be described in detail based on an embodiment shown in the drawings. Reference numeral 1 in FIG. 1 is a vehicular lamp according to the present invention, and in this embodiment, a headlamp is shown as a concrete shape. Here, in the vehicle lamp 1, a lamp chamber 4 is configured such that a front lens 2 and a housing 3 each made of resin are in a substantially sealed state. Inside the lamp chamber 4, a reflecting mirror 5 and the like are provided. The point that the light bulb 6 as a heat source is provided is the same as that of the conventional example.

However, according to the present invention, an antifogging film 7 made of a resin material is formed on the inner wall surface of the front lens 2, that is, the surface on the lamp chamber 4 side. It is said that the occurrence of dew condensation is prevented to prevent fogging.

The antifogging film 7 will be described in more detail below. The antifogging film 7 should be formed in consideration of the adhesion to the member on which the front lens 2 is formed. Is preferable from the viewpoint of durability, and as a specific example, when the front lens 2 is made of acrylic resin, the antifogging film 7 has an acrylic monomer having a hydrophilic group and a hydrophobic group. A Kraft polymer obtained by Kraft polymerizing a monomer having

When the anti-fogging film 7 is formed using the kraft polymer, the craft polymer is dissolved in a solvent such as methyl cellosolve or ethyl cellosolve to form a solution, and a spray method or a flow coating method is used. The antifogging film 7 can be obtained by applying it to the inner wall surface of the front lens 2 by an appropriate means such as a method and heating and drying in an atmosphere of 50 to 100 ° C. for 10 to 40 minutes. At this time, an epoxy resin having a carboxyl group or a silica compound may be added.

When the front lens 2 is made of a polycarbonate resin, the anti-fogging film 7 is a cross-linked polyurethane composed of polycarbonate diol and polyisocyanate, and a polyalkylene polyamine and a dibasic carbon. It is preferably produced by a mixture of a condensation product with an acid, and the blending ratio of the cross-linked polyurethane and the condensation product is preferably in the range of 1: 1 to 2: 1 by weight.

When the antifogging film 7 is formed by a mixture of the crosslinked polyurethane and the condensation product, the condensation product is mixed in an aqueous dispersion of the crosslinked polyurethane in the above weight ratio. Then, the antifogging film 7 is formed by applying it to the inner wall surface of the front lens 2 by an appropriate means such as a spraying method or a flow coating method, and heating and drying in an atmosphere of 100 to 140 ° C. for 10 to 30 minutes. Will be obtained.

Next, the operation and effect of the vehicular lamp 1 of the present invention having the above-described structure will be described. By forming the antifogging film 7 on the inner wall surface of the front lens 2, for example, in cold weather. When a large temperature difference is generated between the inner and outer surfaces of the front lens 2 such as the lighting of the light bulb 6, the air which becomes relatively high in humidity due to the heating inside the lamp chamber 4 is the inner wall surface side of the front lens 2, that is, Condensation occurs when it touches the cloudy film 7, and at this time, as shown in FIG. 2, the adhered water is diffused into a water film 8 due to the hydrophilicity of the anti-fog film 7, and It does not become water drops.

Therefore, when viewing the front surface of the front lens 2 in the above-described state, so-called fog is not recognized, and the water film 8 produced by diffusion due to the hydrophilicity is thin and uniform. In addition, the viewer will not be aware that the water film 8 has been formed, and at the same time, the illuminance and light distribution characteristics will not be substantially affected.

In the above embodiments, when the front lens 2 is made of an acrylic resin, it is a kraft polymer, and when it is made of a polycarbonate resin, it is a mixture of a cross-linked polyurethane and a condensation product to prevent defrosting. Although the example of forming the protective film 7 has been described, the results of the study conducted by the inventor to make the present proposal show that the front lens 2 made of an acrylic resin is an antifogging film of a mixture of a crosslinking polyurethane and a condensation product. It has been confirmed that even if 7 of them are combined, or if the front lens 2 of polycarbonate resin is combined with the anti-fogging film 7 of the kraft polymer, the practical effects are obtained. ..

[0014]

[Effect of the device]

 As described above, according to the present invention, by providing a vehicular lamp in which the resin-based anti-fog coating is formed on the inner wall surface of the front lens, a significant temperature difference is generated between the inner and outer surfaces of the front lens. Even when dew condensation occurs on the inner wall surface, the water content that adheres to the inner wall surface is diffused into a water film with a uniform thickness due to the hydrophilicity of the anti-fogging film, preventing the occurrence of fogging and lowering the illuminance. It is extremely effective in improving the quality and marketability of this type of vehicle lighting by eliminating the deterioration of performance of the vehicle lighting due to poor light distribution and without causing the user to feel uncomfortable. Is.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a vehicular lamp according to the present invention.

FIG. 2 is a sectional view of an essential part showing the operation of the same embodiment.

FIG. 3 is a cross-sectional view showing a conventional example.

[Explanation of symbols]

 1 ... Vehicle lamp 2 ... Front lens 3 ... Housing 4 ... Light room 5 ... Reflecting mirror 6 ... Light bulb 7 ... Anti-fog film 8 ... Water film

Claims (4)

[Scope of utility model registration request] 1. A vehicular lamp having a front lens made of synthetic resin, wherein the front lens is made of an acrylic resin, and an acrylic monomer having a hydrophilic group has a hydrophobic group on an inner wall surface of the front lens. A vehicular lamp having an antifogging film formed of a kraft polymer obtained by kraft polymerization of a monomer. 2. The anti-fogging film is composed of a cross-linked polyurethane composed of a polycarbonate diol and a polyisocyanate, and a mixture of condensation products of a polyalkylene polyamine and a dibasic carboxylic acid. The vehicle lighting described. 3. A vehicular lamp having a front lens made of a synthetic resin, wherein the front lens is made of a polycarbonate resin, and a cross-linked polyurethane made of polycarbonate diol and polyisocyanate is formed on an inner wall surface of the front lens. And an anti-fogging film formed of a mixture of condensation products of polyalkylene polyamine and dibasic carboxylic acid. 4. The antifogging film is made of a kraft polymer obtained by kraft-polymerizing an acrylic monomer having a hydrophilic group with a monomer having a hydrophobic group.
The vehicle lighting described.