Active solid-state devices (e.g. – transistors – solid-state diode – Incoherent light emitter structure
Reexamination Certificate
2001-04-02
2002-05-28
Nelms, David (Department: 2818)
Active solid-state devices (e.g., transistors, solid-state diode
Incoherent light emitter structure
C257S080000, C438S022000
Reexamination Certificate
active
06396081
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a light source for generating visible light, which is composed of a diode on a semiconductor basis or a semiconductor diode emitting light of a specific wavelength and of at least one luminophor into which the emitted light is directed and which luminophor generates visible light of another wavelength from the emitted light.
A light source of this type is known and is offered by Siemens AG located in Berlin and Munich under the trademark LUCO®. Given this light source, the diode is composed of a light diode, which emits blue light. The luminophor generates light in the yellow spectral range by absorption of the emitted blue light. The light outputted by this light source is white light, which results from the superimposition of the light generated in the yellow spectral range and a non-absorbed portion of the emitted blue light.
The known light source has a high efficiency, is constructionally simple, has small dimensions, is inexpensive and only requires a low operating voltage enabling battery operation.
A light source for generating visible light with the aid of a diode on a semiconductor basis is also known, which is composed of three light diodes, whereby a first one only emits the primary color red, a second one only the primary color green and a third one only the primary color blue. These three diodes are arranged, for example, in a housing such that the three emitted primary colors superimpose one another and thus generate white light. A luminophor is not necessary for this light source.
This light source is also highly efficient and only requires a low electrical operating voltage enabling battery operation. The intensities of the three primary colors, however, must be exactly matched to one another. For this reason and due to the necessity of three light diodes and an involved assembly technique, this light source is more involved and expensive compared to the light source of the first cited type.
Both light sources are constructionally simple and can be realized with small dimensions compared to a traditional luminophor lamp, wherein ultraviolet light having a wavelength of 253.7 nm is emitted from a discharge in gas, and which comprises at least one luminophor into which this emitted ultraviolet light beams and which generates visible light from this emitted ultraviolet light. The gas discharge of a luminophor lamp requires high electrical voltage and the dimensions of the lamp cannot downwardly transgress specific values due to constructional reasons. Luminophor lamps reach an efficiency of approximately 20%, which is high compared to the efficiency of approximately 4% of a conventional filament lamp.
Efficiency means the ratio of the optical performance outputted by the respective light source to the electrical performance utilized for generating this performance.
Given the conventional luminophor lamp, a luminophor can be used in the form of a mixture of different luminophor substances, each of which is activated at the wavelength 253.7 nm and respectively visible light of a wavelength having a spectrum composed of a plurality of wavelengths can be generated.
SUMMARY OF THE INVENTION
The invention is based on the object of providing a light source for generating visible light, whereby a significantly greater wealth of visible wavelengths and/or spectrums are available for forming a spectrum of the generated visible light.
This object is achieved by a light source comprising at least one semiconductor diode emitting ultraviolet light and at least one luminophor which generates visible light when the ultraviolet light is directed into the luminophor.
The inventive light source is a source of the aforementioned type, whereby, in contrast to the known light source of this type, the diode does not emit visible blue light but invisible ultraviolet light and whereby the luminophor generates the visible light from the emitted ultraviolet light and not from the emitted blue light.
The visible light generated by the inventive light source is advantageously free of a superimposition of light of a color and free of light of another color from a light diode.
Given the inventive light source, the generated visible light, similar to a conventional luminophor lamp, advantageously stems from the luminophor alone, since the ultraviolet light generated by the diode is invisible.
Advantageously, every arbitrary diode generating ultraviolet light-regardless of the wavelength-can be utilized with respect to the inventive light source. A luminophor must be selected, which is activated given the ultraviolet wavelength, which is generated by the respective diode. Essentially all ultraviolet wavelengths beyond the boundary to the visible violet, particularly the wavelengths of 150 nm to 400 nm, can be advantageously generated by the currently available diodes or by the diodes that will be available at lest in the near future, so that all these wavelengths, which particularly contain the wavelength 253.7 as well, are available to the inventive light source. Separate, particularly also new luminophors, can be used for each of these ultraviolet wavelengths, so that the palette of utilizable luminophors with respect to the inventive light source is much more versatile compared to the conventional luminophor lamp.
Given the conventional luminophor lamp, the ultraviolet light is limited to the very narrow-banded wavelength range (253.7 nm) of the gas discharge. Therefore, only luminophors that are activated at the wavelength 253.7 can be used for the lamp.
In particular, a far greater number of wavelengths and/or specturms of the outputted visible light can be advantageously realized with respect to the inventive light source than before, since not only the visible wavelengths and/or spectrums of the luminophors activated at the individual ultraviolet wavelength 253.7 nm but also the visible wavelengths and/or spectrums of the luminophors activated at the ultraviolet wavelengths that are different from 253.7 are available. The additional visible wavelengths and/or spectrums generated by the additionally available luminophors can advantageously differ greatly among one another and can differ greatly from the visible wavelengths generated by the luminophors that are activated at the individual ultraviolet wavelength 253.7 nm. Given the inventive light source, a considerably greater wealth of visible wavelengths and/or visible spectrums therefore is available for the generated visible light.
Similar to the conventional luminophor lamp, a luminophor in the form of a mixture and/or laminate composed of various luminophor substances, which are activated at one and the same ultraviolet wavelength and which, at this wavelength, can generate a plurality of visible wavelengths and/or spectrums, particularly various spectrums that are situated at a plurality of visible wavelengths, for example, which are available for forming a spectrum of the visible light outputted by the inventive light source, can be advantageously used given the inventive light source.
In contrast to the conventional luminophor lamp, wherein this possibility is limited to the individual ultraviolet wavelength 253.7 nm, this possibility is advantageously given for each individual wavelength of the ultraviolet range, particularly the range of 150 nm to 400 nm, given the inventive light source. Given the inventive light source, visible wavelengths and/or various spectrums situated at visible wavelengths can be generated dependent on the utilized mixtures and/or laminates composed of various luminophor substances but also dependent on the used ultraviolet wavelength, so that the inventive light source, compared to the conventional luminophor lamp, can output visible light of a spectrum, whereby a far greater versatility of visible wavelengths and/or visible spectrums is available for forming said visible light of a spectrum.
A laminate is composed of at least two layers arranged on top of one another, which layers are to be understood as substances that are different from one anothe
Averbeck Robert
Riechert Henning
Tews Helmut
Huynh Andy
Nelms David
Osram Opto Semiconductor GmbH & Co. OHG
Schiff & Hardin & Waite
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