The present disclosure relates generally to a lighting device, and more particularly to a lighting device including two or more diffusers for blending light.
Light emitting diode (LED) based lighting systems may offer several energy and reliability advantages over other types of lighting systems such as, for example, incandescent or fluorescent lighting. Thus, LED based lighting systems may be used to replace other existing lighting technologies. Multicolored LED chips are commonly used in lighting applications where dynamic color mixing is desired. For example, light emitted from different colored LED chips may be mixed together and their respective brightness adjusted in order to produce white light.
One of the challenges faced in a multicolored application is mixing or blending the different colored LED chips properly so as to create uniform light. For example, red, green, and blue light produced by individual LEDs may need to be mixed or blended together to create white light. However, sometimes the light blending is not always consistent. In one approach to alleviate this issue, a solid object may be placed within a lighting device, between the individual LEDs and the diffuser in order to block the light that does not get mixed properly. In another approach, the light sources (e.g., the LEDs) may be positioned closer together such that the light the LEDs generate appears to be combined when viewed from the outside of the light bulb.
In addition to the mixing of light, another challenge faced in LED lighting is the issue of shadowing upon a diffuser of the light bulb. Specifically, sometimes shadows may be cast by objects located within a lighting cavity of the light bulb upon the diffuser. For example, in some types of lamps, the electronic driver circuit board may actually protrude into the lighting cavity. The driver circuit board may cast shadows upon the diffuser of the light bulb. In addition to the electronic driver circuit, other objects located within the lighting cavity that may cast a shadow on the diffuser include, but are not limited to, screws, wires, antennas, and reflectors. Accordingly, the physical structure of the lamp may need to be modified in order to prevent shadows from being cast upon the diffuser. Thus, there exists a continuing need in the art for a lighting device having improved light generating characteristics.
In one embodiment, a lighting device is disclosed, and includes at least one lighting element that emits light, an inner diffuser and an outer diffuser. The inner diffuser defines a lighting cavity and an outer surface, where the at least one lighting element is located within the lighting cavity. The outer diffuser surrounds the inner diffuser. The outer diffuser defines an inner surface. The outer surface of the inner diffuser and the inner surface of the outer diffuser cooperate together to define a space between the inner diffuser and the outer diffuser. The inner diffuser and the outer diffuser spread and blend the light emitted by the at least one lighting element.
In another embodiment, a light emitting diode (LED) light bulb is disclosed, and includes at least one LED for generating light, an inner diffuser, and an outer diffuser. The inner diffuser defines a lighting cavity and an outer surface. The LED is located within the lighting cavity. The outer diffuser surrounds the inner diffuser. The outer diffuser defines an inner surface. The outer surface of the inner diffuser and the inner surface of the outer diffuser cooperate together to define a space between the inner diffuser and the outer diffuser. The inner diffuser and the outer diffuser spread and blend the light generated by the LED.
The following detailed description will illustrate the general principles of the invention, examples of which are additionally illustrated in the accompanying drawings. In the drawings, like reference numbers indicate identical or functionally similar elements.
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The inner diffuser 32 and the outer diffuser 34 may both be any device for spreading and blending light emitted by the lighting elements 28. The inner diffuser 32 and the outer diffuser 34 may both be constructed of any material that allows for the spreading and blending of light such as, for example, plastic such as polycarbonate, or glass. In one embodiment, an outer surface 60 of the inner diffuser 32 may be coated with a material that causes the light generated by the lighting elements 28 to have a specific appearance. For example, if the lighting device 10 is a white light bulb, then the outer surface 60 of the inner diffuser 32 may be coated with white titanium dioxide particles. Additionally or alternatively, an outer surface 62 of the outer diffuser 34 may also be coated with a material as well, such as white titanium dioxide particles.
In one embodiment, the inner diffuser 32 may be constructed of a different material than the outer diffuser 34. For example, in one approach the inner diffuser 32 may be constructed of a plastic, such as polycarbonate, while the outer diffuser 34 may be constructed of glass in order to emulate a traditional light bulb. In an alternative embodiment, both the inner diffuser 32 and the outer diffuser 34 are both constructed of the same material.
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A gap or space 80 may be defined between the inner diffuser 32 and the outer diffuser 34. In one embodiment, the space 80 may be an air-filled gap. Alternatively, the space 80 may be a vacuum instead. In another embodiment, the space 80 may be filled with a material that allows for the transmission of light such as, but not limited to, clear silicon. The outer surface 60 of the inner diffuser 32 and an inner surface 82 of the outer diffuser 34 cooperate together to define the space 80. It is to be understood the geometry or volume of the space 80 should not be limited to the specific configuration as shown in the figures. It is to be understood that the outer surfacer 60 of the inner diffuser 32 may even contact or touch the inner surface 82 of the outer diffuser 34 in one embodiment.
In the embodiment as shown, the outer diffuser 34 includes a generally rounded or dome-shaped profile that corresponds to a type A light bulb. However, it is to be understood that this illustration is merely exemplary in nature. Indeed, the outer diffuser 34 may include any number of shapes or geometries so long as the outer diffuser 34 contains and surrounds the inner diffuser 32. Moreover, as explained above, the outer surface 60 of the inner diffuser 32 may contact the inner surface 82 of the outer diffuser 34.
It is to be understood that providing at least two diffusers for the lighting device 10 (i.e., the inner diffuser 32 and the outer diffuser 34) generally improves light output. More specifically, objects located within the lighting cavity 70 (such as the upper portion 64 the driver board 26) may cast shadows upon the inner diffuser 32. However, because the lighting device 10 includes an additional diffuser (i.e., the outer diffuser 34) for further distribution of light, the shadows created by objects located within the lighting cavity 70 may not be noticeable as the light generated by the lighting elements 28 exits the outer diffuser 34. In other words, the use of multiple diffusers substantially eliminate any shadows created by objects located within the lighting cavity 70 to be cast upon the outer diffuser 34.
It should also be understood that while the figures illustrates two diffusers (i.e., the inner diffuser 32 and the outer diffuser 34), the lighting device 10 should not be limited to just two diffusers. Instead, the disclosed lighting device 10 may include more than two diffusers as well, where each diffuser may be contained by another diffuser that is larger in size. Moreover, while the figures illustrate the inner diffuser 32 having a different geometry than the outer diffuser 34, it is to be understood that the inner diffuser 32 may include a similar shape as the outer diffuser 34, but is smaller in size such that the inner diffuser 32 may fit within the outer diffuser 34.
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In the exemplary embodiment as shown in the figures, the lighting elements 28 are each individual LEDs. For example, in one embodiment, the individual lighting elements 28 (e.g., the LEDs) may be differently colored LEDs, such as red, green, and blue LEDs. The light emitted from the differently colored LEDs may be mixed together by the inner diffuser 32 and the outer diffuser 34 in order to produce white light. It is to be understood that providing multiple diffusers generally enhances and improves the amount of color mixing between the differently colored LEDs, thereby providing a more uniform white light.
Although a uniform white light is discussed, it should be understood that the lighting device 10 is not limited to just producing white light. For example, in another embodiment, the lighting device 10 may produce a light of a different wavelength instead such as, for example, red, green, blue, orange, pink, or violet light. Moreover, it is to be understood that the disclosure is not limited to LED lighting, and the lighting elements 28 may be other types of light emitting elements instead. For example, in another embodiment, the lighting device 10 may be a compact fluorescent light (CFL), or an incandescent light. Moreover, it should also be understood that in another embodiment, the lighting elements 28 may actually reflect light generated from another light source (not shown) that is located within the lighting device 10, or even by a source external to the lighting device 10. For example, the lighting elements 28 may be mirrors or reflectors that may reflect the light generated from the sun.
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Referring generally to the figures, the disclosed lighting device 10 generates more uniform light when compared to some other types of lighting devices currently available that only include a single, outer diffuser. This is because the multiple diffusers cooperate together to distribute the light generated by the lighting elements 28. The multiple diffusers allow for objects, such as the driver board 26, to protrude into the lighting cavity 70 of the lighting device 10, without creating objectionable shadowing along the outer surface 62 of the outer diffuser 34. Moreover, the disclosed lighting device 10 may also result in enhanced color mixing between differently colored LEDs.
While the forms of apparatus and methods herein described constitute preferred embodiments of this invention, it is to be understood that the invention is not limited to these precise forms of apparatus and methods, and the changes may be made therein without departing from the scope of the invention.
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