Electric lamp and discharge devices – With optical device or special ray transmissive envelope – Polarizer or special ray transmission
Reexamination Certificate
1999-11-18
2001-10-09
Day, Michael H. (Department: 2879)
Electric lamp and discharge devices
With optical device or special ray transmissive envelope
Polarizer or special ray transmission
C313S315000, C313S635000
Reexamination Certificate
active
06300710
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a filament lamp for emission of yellow light. The invention relates especially to a filament lamp for emission of yellow light which is advantageously used for a head lamp or a fog lamp of a motor vehicle.
2. Description of Related Art
For example, a lamp which emits yellow light is used as the head lamp or fog lamp for a motor vehicle so that the driver acquires a suitable visual field even in thick fog or rain. In one such lamp, the standard range of chromaticity of the emitted yellow light is established by “ECE Regulation No. 37.”
Conventionally, as the lamp for emitting yellow light which is used for a motor vehicle head lamp a lamp is known which comprises:
a filament lamp with a colorless, transparent bulb;
a concave reflector which surrounds this filament lamp; and
a front glass which is located in an opening of this concave reflector, and in which the front glass is colored yellow by a cadmium-based dye.
However, since a heavy metal, such as cadmium or the like, has adverse effects on the human body, with respect to the environment, it is desirable not to use a material which contains a heavy metal, such as cadmium or the like, in a lamp for a motor vehicle.
As the means for producing a lamp which emits yellow light, providing the outside surface of the lamp bulb with a yellow colored film is known. A composition for producing a yellow colored film is known (published Japanese Patent Application HEI 6-92623). This composition is produced by a solution of an alkyl silicate, such as tetraethoxysilane or the like containing vanadium pentoxide powder with a grain size of less than or equal to 0.2 microns, finely distributed.
However, since a color film which is obtained by this composition does not satisfy the chromaticity range established by “ECE Regulation No. 37” or has a low light beam transmission factor, it is not suited for a color film for a lamp. Furthermore, when a dispersion mixing device, such as a ball mill or the like, is used to distribute the vanadium pentoxide powder, there is the danger that changes in the shade of the color film occur, and a reduction in the light beam transmission factor will arise, as a result of the fact that, when producing the composition, a powder is mixed in originating from the grinding medium and the inside wall of the device which has been formed by abrasion.
Furthermore, a filament lamp for emitting yellow light a lamp is known in which the outer surface of the bulb is provided with a multilayer film in which layers with a low index of refraction, such as silicon dioxide or the like, and layers with a high index of refraction, such a titanium dioxide or the like, are alternately placed on top of one another.
In one such multilayer film, light interference is used. Since it has the property that light is transmitted in a certain wavelength range, and at the same time, also has the property that light is reflected in a certain wavelength range, there is the disadvantage that, depending on the variation of the layer thickness and the radiation angle of the light, light besides yellow light is emitted.
SUMMARY OF THE INVENTION
The invention was devised to eliminate the above described disadvantages of the prior art. Therefore, a first object of the present invention is to devise a filament lamp for emission of yellow light in which yellow light can be emitted without a material being used which contains heavy metals which exert adverse effects on the environment, such as cadmium, lead and the like.
A second object of the invention is to devise a filament lamp for emitting yellow light which has a color film which can be easily produced, which has high transparency and high heat resistance, and in which the desired yellow light can be emitted without a material being used which contains heavy metals which have adverse effects on the environment, such as cadmium, lead and the like.
Theses objects achieved in accordance with the invention by a filament lamp for emitting yellow light which comprises:
a glass bulb,
a filament which is located in the bulb; and
a color film which is formed on the outer surface and/or the inner surface of the bulb, and is produced from a combined oxide of titanium, nickel and antimony.
The objects of the invention are also advantageously achieved by a filament lamp for emitting yellow light in which the above described color film has a weight ratio of titanium, nickel and antimony to one another of 5.6 to 8.6:3.6 to 6.6:1.0 to 1.8.
The objects are furthermore advantageously achieved according to the invention by the above described color film being produced by sintering of a coating liquid which is obtained by mixing the solution A described below with the solution B described below:
(Solution A)
Titanium alkoxide is added to a solution which is produced by dissolving nickel salt in an organic solvent and by dissolving antimony salt in the organic solvent and is reacted. A stabilizer which composed of a compound which can form a chelate with titanium is added to this solution. In this way solution A is produced.
(Solution B)
Water and then titanium alkoxide are added to a solution which is produced by dissolving nickel salt in an organic solvent and by dissolving antimony salt in the organic solvent and is reacted. Afterwards, a stabilizer which composed of a compound which can form a chelate with titanium is added. In this way, solution B is produced.
Basically, suitable organic solvents are all those in which the components used dissolve adequately and which do not lead to unwanted reactions with the reaction participants. Monovalent alcohols, glycolic ethers or acetic acid esters which can be used also in mixtures among one another are especially suitable.
The stabilizer is a compound which can form a chelate with titanium. Preferably, those stabilizers which lead to formation of chelate rings are preferred. It is preferred when the stabilizer is added to the titanium in a roughly stoichiometric amount so that it is ensured that both the titanium and also the stabilizer react essentially completely with one another.
Especially preferred stabilizers are &bgr;-diketones or &bgr;-keto acids. This bivalent stabilizers are feasibly added to the titanium in a molar ratio of roughly 2:1, therefore, in the aforementioned stoichiometric ratio which ensures essentially complete reaction of the two components.
Neither are the salts used especially limited. Suitably, those salts are used which dissolve in the solvent used to a sufficient degree. For example, nickel nitrate, tetraisopropoxy titanium, antimony trioxide, or tetrabutoxy titanium are suitable.
An especially preferred dye solution for sintering is obtained when the solutions A and B are mixed with one another with the weight percentages of 7 to 13 percent by weight nickel nitrate-6-hydrate, 0.6 to 1.2 percent by weight antimony trioxide, 10 to 15 percent by weight tetraisopropoxy titanium and 7 to 12 percent by weight acetyl acetone. Moreover, solution B contains 0.3 to 1.5 percent by weight water. In the coating solution in accordance with the invention, these solutions A and B are advantageously mixed with one another in a weight ratio to one another of 90:10 to 30:70.
In the following, the invention is further described using several embodiments described in the drawings.
REFERENCES:
patent: 4633127 (1986-12-01), Beurskens et al.
patent: 4800319 (1989-01-01), Van Kemenade et al.
patent: 5177395 (1993-01-01), Reisman
patent: 5578892 (1996-11-01), Whitman et al.
patent: 2 183 363 (1987-06-01), None
patent: 6-92623 (1994-04-01), None
J. Hackman, Nickel Antimony Titanate Yellow, Pigment Handbook 2nd ed. vol. 1, p375, Wiley & Sons, 1988.*
J. Hackman, Synthetic Inorganic Complexes, Pigment Handbood 1st ed, vol. 1, p419, 1973.*
Engelhard, Material Safty Data Sheet, Meteor Bright Yellow 8320, cira Nov. 1989.
Fujisawa Shigeki
Minamizono Hiroshi
Nakamori Katsumi
Okumura Yoshihiko
Day Michael H.
Nixon & Peabody LLP
Safran David S.
Ushiodenki Kabushiki Kaisha
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