The present invention relates to the field of electric light bulbs. More specifically, the present invention relates to improved light bulbs that include light emitters of different wavelengths driven by a power source, without separate power regulators for each wavelength of light emitter.
The need for a more energy efficient electric light is clear. Although many attempts have been made to replace the incandescent lamp with LED technology, most are expensive, generate a great deal of heat, have poor omnidirectional light output, or fail to provide adequate spectral light output. Also, the smooth surface of incandescent light bulbs does not attract dirt and is easy to clean unlike the oddly shaped LED lamps offered with their convoluted heat sinks.
Existing LED replacement lamps typically use relatively few very bright LEDs operated at or near their electrical limit to generate sufficient light. This requires a power supply and separate heat sink. Because few individual light emitters are used the light is not radiated in an omnidirectional pattern, forcing awkward additions like reflecting fins, lenses, etc., in an attempt to overcome this shortcoming. For example, a table lamp fitted with a state of the current art LED bulb directs the majority of its light upward making it difficult to read or perform other tasks using such a lamp while sitting in a chair alongside the lamp. Additionally, few emitters may compromise possible improvements in color rendering. Although advances have been made in color temperature, color rendering may remain poor to unacceptable. Finally, few emitters concentrate not only the light but also the heat into a relatively small area, making it difficult to manage.
With the foregoing in mind, embodiments of the present invention are related to an improved light emitting apparatus. Furthermore, the improved light emitting apparatus may advantageously combine several light emitters of different wavelengths. The use of several light emitters may allow each individual light emitter to be run undercurrent, thereby reducing or eliminating the need for heat dissipation while maintaining the overall brightness of the device. Additionally, the use of multiple wavelength light emitters may allow the apparatus to output a broad spectrum of light. The novel electrical configuration of the light emitters allows all light emitters, even those outputting disparate wavelengths to be connected to a single power source while maintaining an essentially steady output wavelength profile. That is, separately regulated power supplies are not required for LEDs outputting disparate wavelengths. LEDs outputting disparate wavelengths may be powered by a single power profile and maintain a relatively constant output of each wavelength relative to the other wavelengths present in the apparatus.
The light emitters of the inventive apparatus may be connected to one another in a series or parallel configuration driven by a single power source, even though they may output disparate wavelengths of visible light. A separate power supply is not required for each color light emitter because the configuration of the inventive apparatus maintains essentially the same relative outputs of different light emitters, even if the different light emitters have different frequency spectrums, even as the power supply undergoes anticipated, or normal, fluctuations in current or voltage. Additionally, it is not necessary to provide feedback controls to a power supply to compensate for frequency spectrum output variations that may occur as the temperatures of the light emitters fluctuate. Due to the novel configuration of the inventive apparatus, the temperature or voltage fluctuation affecting any light emitter may occur proportionally to other light emitters and, due to the electrical connections between light emitters, may not need to be tightly controlled. Additionally, the fluctuation occurring in a single light emitter may have a negligible effect on the overall frequency spectrum of the apparatus, due to the large number of light emitters utilized in the design, and therefore be unnecessary to tightly regulate.
These and other features and advantages according to an embodiment of the present invention are provided by electrically connecting multiple light emitters with different voltage thresholds in a series or parallel configuration as described herein.
a is a schematic diagram of possible embodiments of the inventive apparatus.
a is a diagram illustrating an exemplary output frequency spectrum.
b is a diagram illustrating an exemplary output frequency spectrum.
c is a diagram illustrating the addition of exemplary output frequency spectrums.
The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Those of ordinary skill in the art realize that the following descriptions of the embodiments of the present invention are illustrative and are not intended to be limiting in any way. Other embodiments of the present invention will readily suggest themselves to such skilled persons having the benefit of this disclosure. Like numbers refer to like elements throughout.
In this detailed description of the present invention, a person skilled in the art should note that directional terms, such as “above,” “below,” “upper,” “lower,” and other like terms are used for the convenience of the reader in reference to the drawings. Also, a person skilled in the art should notice this description may contain other terminology to convey position, orientation, and direction without departing from the principles of the present invention.
Referring to
The light emitters 102 may be operated below their respective rated forward voltages. This may allow the light emitter 102 to output significantly less heat and may significantly alleviate the need for heat dissipation from the apparatus 100. An effect of operating the light emitters 102 in under voltage conditions is that each light emitter 102 may produce less lumen. This may be addressed by increasing the total number of light emitters 102 utilized in the apparatus 100. The use of numerous light emitters 102 distributed over a relatively large area aids in heat dissipation and may alleviate the need for a heat sink. A power versus brightness balance may be reached when the generated heat is manageable without use of bulky heat sinks and the amount of light generated provides sufficient illumination. The ambient temperature of the operating environment and the forward current de-rating curves for the light emitters 102 may be utilized in achieving the power versus brightness balance.
In one embodiment of the light emitting apparatus 100, at least two serial light emitters 102 may comprise a first series string 101. Each light emitter 102 will have a frequency spectrum. The frequency spectrums of the two serial light emitters 102 may be not be essentially equal to one another. For example, and not by way of limitation, the first serial light emitter may output a light that is essentially red, with a dominant wavelength of 625 nm. An exemplary frequency spectrum of such a light emitter is depicted in
The apparatus 100 may be made up of light emitters 102 of multiple colors in various combinations to produce light of any desired target frequency spectrum, including, but not limited to any desired color, part or parts of the visible color spectrum, the full visible color spectrum, or the like. It may be beneficial to utilize a variety of light emitters outputting a variety of frequency spectrums as a goal may be to provide light at all visible wavelengths for the best possible color rendering.
In one embodiment of the inventive apparatus 100, the frequency spectrums or rated forward voltages of one or more of the light emitters 102 connected in a serial configuration may be disparate.
Each series string 201 has a series rated forward voltage equal to the sum of the rated forward voltages of each of the light emitters 201 or adjusting diodes in the series string 201. The series rated forward voltages of different series strings 201 which are connected in parallel may be unequal. However, when such series strings 201 are connected in parallel with one another, the actual voltage drop across the series strings 201 will be equal.
Each series string 201 has a series frequency spectrum equal to the sum of the frequency spectrums of each of the light emitters 202 in the series string 201. The series frequency spectrum of different series strings 201, which may be connected in parallel, may be unequal.
Each apparatus 200 may be connected to a power supply, which has a voltage and current profile (collectively, “power profile”). Often times, when driving LEDs, a power supply is regulated to provide voltage and current profiles to the LED which remain within tight tolerances. In some existing LED configurations, the relative brightness of LEDs with different frequency spectrums are tightly controlled by regulated power supplied to each LED and specifically by providing disparate power profiles to LEDs with disparate frequency spectrums or rated forward voltages. In the inventive apparatus 200, at least one light emitter 202 in each of the plurality of series strings 201 may receive the identical current and voltage profile from a power source. Each light emitter 202 in the apparatus 200 may receive the same current profile, modulated only by other light emitters or adjusting diodes in the apparatus 200. It may be unnecessary to regulate power independently for each series string 201. According to the inventive apparatus 200, it is not necessary to provide separate power profiles to light emitters 202 with disparate rated forward voltages or frequency spectrums. Rather, the electrical configuration of the inventive apparatus 200 operates to maintain relative brightness of disparate light emitters 202 within tolerances deemed suitable to maintain pleasing task, decorative, or functional lighting. Therefore, power regulators are not required in the inventive apparatus 200. Without separate power regulators for each group of light emitters 202 outputting a particular frequency spectrum the apparatus 200 may still maintain the target frequency spectrum output.
Utilizing the inventive configuration of light emitters 202, each light emitter 202 in a particular series string 201 may receive essentially the same current profile, while the voltage drop across each light emitter 202 may vary based upon characteristics inherent to the light emitter 202. Light emitters 202 with characteristics which produce different voltage drops across the light emitter 202 may be freely mixed within any series string 201. Adding additional light emitters 202 to a series string 201 may reduce the current to all light emitters 202 in the series string 201 by a small amount, while subtracting light emitters 202 may increase the current to all light emitters 202 in the series string 201. The current level required by the light emitters 202 to achieve the desired power versus brightness balance may be determined by choosing the correct number and combination of light emitters 202 in a series string 201 to match the voltage supplied by the desired power supply. An apparatus 200 that will be supplied by a higher voltage supply may require more light emitters 202 than one that will be supplied by a lower voltage supply. Alternatively, an apparatus 200 that may be supplied by a higher voltage supply may utilize light emitters 202 that have a higher voltage drop than one that is supplied by a lower voltage supply. The quantity of each light emitter 202 utilized in the apparatus with a specific frequency spectrum determines the overall frequency spectrum of the apparatus 200, so frequency spectrum of light emitters 202 must be considered in addition to voltage drop across the light emitters 202 when designing the apparatus 200. As the selection of voltage drop across a light emitter 202 is related to the frequency spectrum output of the light emitter 202, it may be important to note that it is not necessary for each individual series string 201 to match the target frequency spectrum. However, the combination of the frequency spectrums of all series strings 201 in the apparatus 200 should match, or approximate, the target frequency spectrum.
The frequency spectrum of each light emitter 202 in the configuration may optically combine with the frequency spectrums of the other light emitters in the configuration to produce a target frequency spectrum.
Turning to
According to the embodiment depicted in
In one embodiment of the inventive apparatus 300, a plurality of capacitors 306 may be electrically connected to the input of a plurality of light emitters 302. Separate capacitors 306 may be connected to the input of each light emitter 302 or capacitors 306 may be connected to the inputs of groups of light emitters 302.
Each supplemental light emitter added to the starting configuration may be powered by the same power source provided to the starting configuration, with no need to regulate the power to the supplemental light emitters according to characteristics inherent to the light emitters. The starting configuration or supplemental light emitters may be supplied with a current less than that for which the light emitter may be rated or less than that at which the light emitter may operate most efficiently.
A person of skill in the art will appreciate that one or more of the above provided embodiments may be included in designing the light emitting apparatus of the present invention. Additionally, a person of skill in the art will appreciate additional embodiments that would be included within the scope and spirit of the present invention, after having the benefit of this disclosure. Furthermore, a skilled artisan will appreciate that the operations described above, along with additional operations that would be apparent to those in the art, may be performed exclusively, incrementally, sequentially, simultaneously, or any other operative configuration.
Many modifications and other embodiments of the invention will come to the mind of one skilled in the art having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is understood that the invention is not to be limited to the specific embodiments disclosed, and that modifications and embodiments are intended to be included within the scope of the appended claims.