Patent Grant
9140421
The present disclosure relates generally to a lighting device and, more particularly, to a lighting device using light emitting diodes (LEDs).
For some lighting applications, e.g., domestic lighting, direct and indirect lighting have different purposes. For example, direct lighting is used for reading, while indirect lighting is used to provide a comfortable atmosphere. More light emitting diodes (LEDs) are used nowadays for many lighting applications, including domestic lighting. Direct lighting and indirect lighting using LEDs are provided by separate lighting devices with different layouts, which can be costly and inconvenient.
A lighting device includes a first heat sink having a first surface and a second surface, and a second heat sink having a third surface and a fourth surface. The third surface is bonded to the second surface. The lighting device includes a plurality of first light emitting diode (LED) modules mounted on the first surface, and a plurality of second light emitting diode (LED) modules mounted on the fourth surface. One or more the first LED modules radiates lights in a first direction. One or more the second LED modules radiates lights in a second direction. The first and second LED modules are covered by respective non-reflective caps. The first and second LED modules are selectively turned on or off. The first LED modules are arranged on an outer region of the lighting device, and the second LED modules are arranged on an inner region of the lighting device.
Reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:
The making and using of various embodiments are discussed in detail below. It should be appreciated, however, that the present disclosure provides many applicable inventive concepts that can be embodied in a wide variety of specific contexts. The specific embodiments discussed are merely illustrative of specific ways to make and use, and do not limit the scope of the disclosure.
Light caps 103a and 103b are used to cover (enclose) the LED modules 102a and 102b. The light caps 103a and 103b can have arbitrary shapes and colors, which may be transparent, semitransparent, or partially transparent, etc., depending on applications. The heat sinks 110a and 110b can be one piece or multiple pieces held together (by bonding or by other mechanical means), depending on appearance and mechanical design. Good thermal management could be achieved by various arrangements of heat sinks 110a and 110b with different shapes, e.g., circular, square, rectangular, ring, band, linear, etc.
The lighting device 100 can be mechanically fixed in various ways, e.g., hung from the ceiling, mounted on a pole or stand (not shown), etc. The lighting device 100 with the LED modules 102a and 102b mounted at different directions is suited for multi-directional lighting applications. In particular, the double-sided design shown in
According to table 1, only direct lighting LED modules such as 102b are turned on at the first setting in the sequence, e.g., with a switch or button operation. At the second setting in the sequence, only indirect lighting LED modules such as 102a are turned on. At the third setting in the sequence, both are turned on, and at the fourth setting in the sequence, both are turned off. There can be many variations on the operation of the settings in the sequence. For example, there can be more settings in the sequences than just four settings as in Table 1, and the controlled units can be different (e.g., half of the direct lighting LED modules can be controlled separately from the other half of the direct lighting LED modules, etc.)
The substrate 116 could comprise silicon, ceramic, or any other suitable material. In some embodiments, a complex integrated circuit with LED or other detector circuit can be fabricated based on silicon processes. The substrate 116 can have different thicknesses, e.g., about 400 μm (but could be thicker or thinner). The substrate 116 is mounted on the PCB 118. In various embodiments, different PCBs, e.g., a PCB including FR-4, an Al-based metal core PCB (MCPCB), or Cu-based MCPCB, or any other kinds of PCB can be used. The PCB allows easier installation of the LED module and for effective thermal-conductive function.
The heat sinks 110a and 110b can comprise Al, Cu, Ag, Fe, any combination thereof, or any other suitable material. The dimension of the heat sinks 110a and 110b depends on specifications (e.g., how much power or heat, temperature requirements, etc.). For example, a 10 W LED source may need greater than 30000 mm2 of heat spreading in some embodiments.
In
The arrangement scheme can be varied and there can be different mixing of LED modules for different lighting directions, e.g., a part of inside LED modules 204 can be mounted on the same side as the outside LED modules 202 for a different lighting direction from the rest of the inside LED modules 204 (i.e., the same lighting direction as the outside LED modules 202). There can be many other variations with different shapes such as triangular, rectangular, oval, star-shape, etc. for different arrangements.
In
For example, the thermal grease can be ceramic-based, metal-based, carbon based, liquid metal based, etc. Ceramic-based thermal grease is a ceramic powder suspended in a liquid or gelatinous silicone compound, which may be described as silicone paste or silicone thermal compound, e.g., beryllium oxide, aluminum nitride, aluminum oxide, zinc oxide, and silicon dioxide. Metal-based thermal grease contain solid metal particles (usually silver or aluminum). Carbon based thermal grease may contain diamond powder or short carbon fibers. A liquid metal based thermal grease contains liquid metal alloys, e.g., of gallium.
In
According to some embodiments, a lighting device includes at least one heat sink. At least two light emitting diode (LED) modules are mounted on the at least one heat sink. The at least two LED modules are mounted at different directions on the at least one heat sink so that a first LED module of the at least two LED modules generally radiates lights in a first direction for a direct lighting and a second LED module of the at least two LED modules generally radiates lights in a second direction for an indirect lighting by reflecting on a surface.
According to some embodiments, a method of fabricating a lighting device includes mounting at least two light emitting diode (LED) chips on substrates for forming at least two LED modules. At least two LED modules are mounted at different directions on at least one heat sink so that a first LED module of the at least two LED modules generally radiates lights in a first direction for a direct lighting and a second LED module of the at least two LED modules generally radiates lights in a second direction for an indirect lighting by reflecting on a surface.
A skilled person in the art will appreciate that there can be many embodiment variations of this disclosure. Although the embodiments and their features have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the embodiments. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, and composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosed embodiments, processes, machines, manufacture, compositions of matter, means, methods, or steps, that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present disclosure.
The above method embodiment shows exemplary steps, but they are not necessarily required to be performed in the order shown. Steps may be added, replaced, changed order, and/or eliminated as appropriate, in accordance with the spirit and scope of embodiment of the disclosure. Embodiments that combine different claims and/or different embodiments are within the scope of the disclosure and will be apparent to those skilled in the art after reviewing this disclosure.
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| Number | Date | Country | |
|---|---|---|---|
| 20130039041 A1 | Feb 2013 | US |
