Background Art In general, a vehicle lamp unit consists of a reflective plate, a front lens provided on a front side of the reflective plate, and an incandescent lamp provided inside of the reflective plate and the front lens. Recently, the front lens is made of a transparent material. The incandescent lamp provided inside of a vehicle sometimes uses a colored light-emitting bulb.

However, there is a problem in that the color of the tight-emitting bulb shows through around the reflective plate since the colored light-emitting bulb is not coated. Accordingly, the incandescent lamp requires an additional cover to prevent the color of the light-emitting bulb from showing through, resulting in an increase in the production cost of a vehicle lamp unit.

In order to overcome the aforementioned problem, there has been provided an incandescent lamp where a colored light-emitting bulb is coated with chrome, whereby the incandescent lamp has a metallic color. However, there have occurred other problems that environmental concerns, such as pollution resulting from the disposal of a foam agent, are left out of consideration, and the light intensity of the incandescent lamp decreases remarkably.

Description of Drawings The above and other features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings in which: FIG. 1 is a cross-sectional view showing a vehicle lamp unit equipped with a heatproof oxide-coated incandescent lamp according to the present invention.

Technical Problem An object of the present invention is to provide a heatproof oxide-coated incandescent lamp in which a metal-colored oxide film is formed on an outer surface of a colored light- emitting bulb, and by which a vehicle lamp unit with a neat appearance can be provided.

In order to achieve the above object, there is provided a heatproof oxide-coated incandescent lamp comprising a light-emitting bulb 5 and an oxide film 6 formed on an outer surface of the light-emitting bulb 5, wherein the oxide film 6 is composed of an oxide particle, which is made by coating an oxide having a low index of refraction with an oxide having a high index of refraction, and an inorganic polymer made of silica and titanium oxide.

Technical Solution According to the present invention, there is also provided a heatproof oxide-coated incandescent lamp, wherein the oxide particle is made of a mica particle coated with titanium oxide.

According to the present invention, there is also provided a heatproof oxide-coated incandescent lamp, wherein the inorganic polymer is a solution made by hydrolysis of silicon alkoxide and titanium alkoxide.

Therefore, it is possible to provide an oxide film which has a high heatproof property and a metallic color due to a mica particle and an inorganic polymer formed on an outer surface of a light-emitting bulb and can prevent a decrease in the light intensity of an incandescent lamp by use of the mica particle having a component ratio of between 3 and 20% by taking the light intensity of an incandescent lamp into account.

Accordingly, an additional cover is not necessary besides a transparent front lens since the color of the light-emitting bulb is not visible, whereby a vehicle lamp unit can be manufactured at low cost and with a neat appearance.

Advantageous Effects According to a heatproof oxide-coated incandescent lamp of the present invention, it is possible to provide an oxide film 6, which has a high heatproof property and a metallic color due to a mica particle and an inorganic polymer formed on an outer surface of a light-emitting bulb 5 and can prevent a decrease in the light intensity of an incandescent lamp 4 by use of the mica particle having a component ratio of between 3 and 20% by taking the light intensity of an incandescent lamp 4 into account. Accordingly, an additional cover is not necessary besides a transparent front lens 3 since the color of the light-emitting bulb 5 is not visible, whereby a vehicle lamp unit 1 can be manufactured at low cost and with a neat appearance.

Best Mode Since an oxide film 6, which is formed on an outer surface of a colored light-emitting bulb 5 of a heatproof oxide-coated incandescent lamp 4 provided inside of a reflective plate 2 and a transparent front lens 3 of a vehicle lamp unit 1, has the same metallic color as the reflective plate 2, the color of the light-emitting bulb 5 is not visible and thus an additional cover is not necessary besides the transparent front lens 3, whereby the vehicle lamp unit 1 can be manufactured at low cost and with a neat appearance.

Meanwhile, the heatproof oxide-coated incandescent lamp 4 is not limited to the vehicle lamp unit 1 but may be employed in a typical lamp which should have a neat appearance.

Mode for Invention The present invention will now be described more fully with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown.

FIG. 1 is a perspective view showing a construction of a vehicle lamp unit 1. The vehicle lamp unit 1 comprises a reflective plate 2, a transparent front lens 3 provided on a front side of the reflective plate 2, an incandescent lamp 4 fixed on a top side of an inner space surrounded by the reflective plate 2 and the front lens 3.

On the outer surface of a light-emitting bulb 5 of the incandescent lamp 4, there is applied an oxide film 6 composed of a mica particle, which is coated with titanium oxide, and an inorganic polymer, which is made of silica and titanium oxide.

Here, the mica particle composing the oxide film 6 has a diameter of 2-100 ; um, and

the titanium oxide coating rate is 10-50%.

In addition, the inorganic polymer, together with the mica particle, composing the oxide film 6 is a solution made by hydrolysis of silicon alkoxides and titanium alkoxide.

That is, the solution is made by mixing 30-60% silicon alkoxide hydrolyzed by 1-12 % water with 2-30% titanium alkoxide and then adding 0. 0-3. 0% viscosity-enhancement agent thereto.

Here, examples of silicon alkoxide include trimethoxysilane (TMS), triethoxysilane (TES), methyltrimethoxysilane (MTMS), and methyltriethoxysilane (MTES). Examples of titanium alkoxide include titanium tetra-n-butoxide, titanium ethoxide, and titanium isoproxide.

In addition, examples of solvents, which are mixed with the inorganic polymer, include ethyl acetate, isopropyl alcohol, ethanol, dipropylene glycol, etc.

Meanwhile, the oxide film 6 has a component ratio of a mica particle: an inorganic polymer = 3-20% : 80-97%. The mica particle not greater than 3% results in an insufficient coating, and the mica particle not less than 20% results in a remarkably reduced light intensity. Accordingly, the mica particle coating ratio is preferably between 3 and 20%.

The heatproof oxide-coated incandescent lamp with the aforementioned structure comprises the metal-colored oxide film 6, which has a high heatproof property and is formed to have a component ratio of a mica particle : an inorganic polymer = 3-20% : 80-97% on the outer surface of the light-emitting bulb 5. Accordingly, it is possible to prevent the light intensity of the incandescent lamp from decreasing by use of the mica particle having a coating ratio between 3 and 20%.

In addition, it is possible to simply form the oxide film 6 since the oxide film 6 is applied

in a spray manner.

Since an oxide film 6, which is formed on an outer surface of a colored light-emitting bulb 5 of a heatproof oxide-coated incandescent lamp 4 provided inside of a reflective plate 2 and a transparent front lens 3 of a vehicle lamp unit 1, has the same metallic color as the reflective plate 2, the color of the light-emitting bulb 5 is not visible and thus an additional cover is not necessary besides the transparent front lens 3, whereby the vehicle lamp unit 1 can be manufactured at low cost and with a neat appearance.

Meanwhile, the heatproof oxide-coated incandescent lamp 4 is not limited to the vehicle lamp unit 1 but may be employed in a typical lamp which should have a neat appearance.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. The exemplary embodiments should be considered in descriptive sense only and not for purposes of limitation.

Therefore, the scope of the invention is defined not by the detailed description of the invention but by the appended claims, and all differences within the scope will be construed as being included in the present invention.