Illumination – Light source and modifier – Including selected wavelength modifier
Reexamination Certificate
2000-08-14
2003-02-18
O'Shea, Sandra (Department: 2875)
Illumination
Light source and modifier
Including selected wavelength modifier
C362S255000, C313S635000, C313S111000
Reexamination Certificate
active
06520664
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a colored luminaire, in particular a colored signaling light for automobiles, provided with a lamp and a luminaire cover inside which the lamp has a bulb with a coating of a layer comprising an organic pigment.
Colored luminaires are used in automobiles in various locations, for example for brake lights, indicator lights, and fog lights. In conventional colored luminaires, the bulb of the lamp is made from colorless glass, and the lamp is positioned under a colored, usually red or yellow luminaire cover. A more recent development involves the use of colored lamps for colored luminaires under a colorless or neutrally colored cover. This renders it possible to incorporate signaling lamps of various types as a group of lamps under one and the same luminaire cover.
Luminaires with colored lamps under a colorless or neutrally colored cover have the advantage that they render possible a flexible, optically attractive design for integrated front and rear luminaires. In addition, they are cheaper than luminaires with multiple housings or covers of various colors. These luminaires in addition are safer in traffic because the difference between switched-on and switched-off lights is more clearly noticeable in daylight in the case of luminaires having colored lamps and a colorless or neutrally colored luminaire cover.
In principle, inorganic or organic color pigments may be used for the colored, pigmented bulb coating of colored lamps. The known red and yellow inorganic color pigments are stable in the long term, but they do not have optimum colorimetric values. Bulb coatings with organic color pigments, for example the coatings with red pigments from the group of anthrachinon pigments known from JP-A-60 116958, can indeed be optimized as regards their color co-ordinates, but they tend towards the yellow in time.
As in many other branches of industry, the trend in the case of automobile lamps is towards an ever increasing miniaturization. Efforts are made to reduce the overall dimensions of the lighting units of an automobile and, for example, to integrate the signaling lights into the main lights. The lamps in such lighting units, however, are subjected to higher thermal loads.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a colored luminaire fitted with a lamp and a luminaire cover in which the lamp has a bulb with a coating of a layer comprising an organic color pigment, which lamp has a long useful life also at elevated ambient temperatures as well as optimized color co-ordinates, and which lamp is suitable for an automobile lighting unit.
According to the invention, this object is achieved by means of a colored luminaire fitted with a lamp and a luminaire cover wherein the lamp has a bulb coating with a first layer comprising a pigment, which pigment is chosen from a group comprising perylene pigments, perinone pigments, isoindoline pigments, and thioindigo pigments.
A luminaire with such a lamp has a long useful life. It is not attacked by UV radiation, moisture, and spray salt and is resistant to temperatures of between 250 and 350° C. Colored luminaires with bulb coatings comprising these pigments alone or in combination with further pigments for color correction comply with the color standards for automobile lights as defined by the E.C.E. for Europe and the S.A.E. for the USA.
In a preferred embodiment, the first pigment-containing layer in addition comprises an iron oxide pigment. An iron oxide pigment in the layer corrects the color value of the organic pigment, for example in the bluish range, for example from yellow to amber, or from orange/red to red. If the lamp is exposed to temperatures above 250° C. for a longer period in the luminaire, it will still have emergency running properties.
It may be preferable that the first pigment-containing layer comprises an iron oxide pigment and a silicon-oxygen compound. Such a layer adheres very well to the glass of the lamp bulb.
In a further preferred embodiment of the invention, a second pigment-containing layer is arranged between the bulb and the first pigment-containing layer, which second layer comprises an iron oxide pigment. If the lamp is exposed to strong and frequent temperature changes and the upper layer should flake off, this embodiment of the luminaire also has emergency running properties.
A transparent layer comprising a silicon-oxygen compound may be arranged between the bulb and the first pigment-containing layer. The mechanical strength of the coating is improved thereby.
It is also possible that the lamp comprises a transparent covering layer comprising a silicon-oxygen compound so as to improve the scratch resistance of the pigment-containing coating.
The invention also relates to a lamp with a bulb having a coating of a layer comprising a pigment chosen from a group which comprises the perylene pigments, perinone pigments, isoindoline pigments, and thioindigo pigments.
The invention will be explained in more detail below with reference to three embodiments.
A colored luminaire according to the invention is provided with a lamp and a luminaire cover inside which the lamp is present and comprises a bulb with a coating of a layer comprising a pigment chosen from the group of the perylene pigments, perinonepigments, isoindoline pigments, and thioindigo pigments.
Depending on the construction of the lamp, the coating may be provided on one or several walls of the lamp bulb, both on the inside and on the outside of the bulb.
The colored luminaire may in addition be fitted with other components, for example means for fastening the lamp in the luminaire, protection means against dust, damage, and moisture, as well as the components necessary for power supply, for example lampholders, cables, ballasts, starters, ignition devices, and connection terminals. A desired light distribution and a dazzle limitation may be achieved by means of optical reflectors, clear or frosted closing plates, rasters of metal or synthetic resin, scattering glass plates, and prismatic reflectors. In an embodiment of the invention, the luminaire contains two or more colored lamps under a joint luminaire cover which is colorless or neutrally colored.
Perylene, perinone, isoindoline, or thioindigo pigments are used for the first pigment-containing layer. The pigments used are polycyclical pigments which have been known for a longer time for coloring textile fibers. The pigments will be denoted hereinafter in accordance with their chemical structures or their color index (C.I.) as published jointly by Society of Dyers and Colourists and the American Association of Textile Chemists and Colorists.
Perinones [CAS 4424-06-0 (trans-perinone), CAS 4216-02-8 (cis-perinone)] are derivatives of 1,4,5,8-naphthalenetetracarbonic acid. Cis- and trans-perinone are obtained as a cis/trans isomer mixture through heating of 1,4,5,8-naphthalenetetracarbonic acid in the form of its monoanhydride, for example in glacial acetic acid at 120° C., with o-phenylenediamine. When the isomers are separated, the trans-perinone is obtained with a pure orange-yellow color and the cis-perinone with a red color.
The perylene pigments are derivatives of 3,4,9,10-perylenetetracarbonic acid. Preferably used may be: the reddish yellow and yellow pigments perylenetetracarbonic-acid bis(methylimide) PR 179 (CAS 5521-31-3), perylenetetracarbonic-acid dianhydride PR 224 (CAS 3049-71-6), bis-dimethylphenylperylimide PR 149, and perylenetetracarbonic-acid diimide) PV 29 (CAS 81-33-4). Generally, the perylene pigments are manufactured from 3,4,9,10-perylenetetracarbonic-acid anhydride through conversion with primary aliphatic amines or substituted anilines, possibly in the presence of a catalyst.
The isoindoline pigments have as their central structural element an isoindoline ring which may be substituted with various substituents via a C═C double bond. Depending on the substituent, the isoindoline pigments are yellow, orange, or red in color. PY 139 (CAS 36888-99-0) with the general formu
Amrein Thomas
Gruhlke Stefan
Opitz Joachim
DelGizzi Ronald E.
Halajian Dicroan
Keegan Frank
Koninklijke Philips Electronics , N.V.
O'Shea Sandra
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