The patent's assignee is
News editors obtained the following quote from the background information supplied by the inventors: "As everyone knows, LED illumination has irreplaceable advantages, such as energy saving, low power consumption, and electrical-to-optical conversion efficiency near to 100%. It can save more than 80% energy compared with the traditional light source with the same illuminating efficiency and has a longer service life. In view of the above advantages, the LED is more and more used as a light source such as a lot of LED retrofit lamps in the market. Such LED retrofit lamps have the same appearance and profile as the traditional light source such as incandescent lamp or lamp tube, thus they can be more applicable to the existing illuminating systems as a light source.
"An LED retrofit lamp is disclosed in the prior art. The LED retrofit lamp has a lamp holder connected with a power supply a heat sink that has one end fixed on the lamp holder and the other end thermally contacting a printed circuit board carrying an LED chip, and a hemispherical bulb provided at the other end of the heat sink to enclose the printed circuit board carrying the LED chip. The heat sink of such LED retrofit lamp is configured to be hollow with an LED driver arranged therein for the LED chip. However, the light intensity distribution of such LED retrofit lamp is not quite uniform because the bulb used as a diffuser usually has a simple structure made from a glass or plastic, while such diffuser cannot distribute the light according to requirements and merely can slightly change the beam angle.
"Another prominent shortcoming is a low inner space utilization ratio of such LED retrofit lamp. In the existing LED retrofit lamp, the LED chip usually should be arranged uniformly and symmetrically on the printed circuit board in order to distribute the light on various directions as uniformly as possible. In this situation, the printed circuit board divides the LED retrofit lamp into two parts, i.e. a heat sink part below the printed circuit board, and a bulb part over the printed circuit board. As the LED driver for driving the LED chip is arranged in the heat sink, and the inner space of the heat sink is limited, the volume of the LED driver is required to be reduced as small as possible. As everyone knows, reduction of the volume of the electronic device leads to notable increase of the cost, which obviously increases the cost of the LED retrofit lamp."
As a supplement to the background information on this patent application, VerticalNews correspondents also obtained the inventors' summary information for this patent application: "Therefore, various embodiments provide an LED lighting assembly that is characterized by good light intensity distribution performance, high inner space utilization ratio and simple structure, and is easily manufactured. In addition, various embodiments provide an LED retrofit lamp having the LED lighting assembly of the type above.
"According to various embodiments, the LED lighting assembly has a printed circuit board with an LED chip, a heat sink thermally conducted with the printed circuit board, wherein the LED lighting assembly further comprises a light guide body configured as a bulb, the light guide body having an end surface as a light input coupling surface of light from the LED chip, an outer surface as a light emergent surface and an inner surface, and wherein the inner surface is structured so as to form a reflecting surface reflecting at least part of light from the end surface to the outer surface. In the LED lighting assembly according to the present disclosure, the bulb is configured as the light guide body, after the light goes into between the inner and outer surfaces of the bulb from the end surface, it is reflected by the reflecting surface which then changes an emergent angle of the light and enables the light intensity distribution of the light to be more uniform on the light emergent surface of the whole bulb.
"According to various embodiments, a plurality of annular grooves is provided on the inner surface. The annular grooves are spaced apart in a direction from the end surface to a top of the bulb. With the configuration of the annular grooves on the inner surface, reflecting surfaces facing to the light emergent surface are formed on the inner surface, so that an emergent angle and light intensity distribution of the light are adjusted using the reflecting surfaces.
"Preferably, a cross section of the annular groove is in a V shape, and the reflecting surface is defined by two groove side surfaces of the V shape-annular groove, wherein the reflecting surface faces to the outer surface. The light coming from the end surface projects onto the reflecting surface constructed by the groove side surfaces in a V shape and is reflected to an expected direction.
"Further preferably, a plane defined by each annular groove is parallel to a plane defined by the end surface. Such configuration of the annular groove provides an arrangement rotationally symmetrical in relation to an optical axis so that the LED lighting assembly according to the present disclosure obtains illumination rotationally symmetrical in relation to the optical axis.
"According to various embodiments, the end surface is supported on the printed circuit board, and is provided with an accommodating recess in which the LED chip is received. As the LED chip is often arranged to protrude from the printed circuit board, the arrangement of the accommodating recess on the end surface can well receive the LED chip therein so as to make the assembling easier with a pleasing appearance and a compact structure.
"According to various embodiments, an interval between the annular grooves in a direction from the end surface to the top of the bulb gradually becomes smaller. As the distance from the annular groove to the LED chip becomes bigger, the interval between the annular grooves gradually gets smaller, which is favorable for obtaining a uniform light intensity distribution.
"Preferably, an angle between two groove side surfaces of each annular groove is in a range of 60.degree. to 120.degree.. Further preferably, the bulb is divided in the direction from the end surface to the top of the bulb into a bottom area, a middle area and a top area, wherein an angle between two groove side surfaces of the annular groove in the bottom area, middle area and top area is 120.degree.-110.degree., 110.degree.-80.degree., and 80.degree.-60.degree., respectively. As the distance from the annular groove to the LED chip gets bigger, the angle between two groove side surfaces of each annular groove gets smaller, so as to obtain a predetermined illuminating angle range by selecting different angle ranges.
"According to various embodiments, the LED lighting assembly further has an additional reflecting cover neighboring the inner surface in an inner side of the bulb. The light from the LED chip cannot be completely reflected by the reflecting surfaces and goes through the light emergent surface, but part of the light may pass through the inner surface to go into an inside of the bulb, thus the additional reflecting cover is provided in the inside of the bulb to reflect this part of light out of the bulb so as to reduce light loss as small as possible.
"According to various embodiments, the printed circuit board has an excavated central region and a peripheral region arranged with the LED chip. Preferably, the heat sink is provided with a hollow region communicated with the central region of the printed circuit board. Thus, the bulb and the heat sink jointly define a relatively big installation space to accommodate electronic devices such as LED driver. This prominently increases an inner installation space of an LED electronic assembly, improves a space utilization ratio thereof, and there is no need to make a compromise on the size of the electronic devices such as LED driver because of a crowded inner installation space.
"According to various embodiments, the bulb is configured to be a hemispherical shape with a cavity or a hollow column, cube, pyramid or cone.
"Advantageously, the bulb consists of two, four or six sub bulbs equally divided on a circumference thereof, and these sub bulbs are bonded or welded together. This extremely simplifies the manufacturing difficulty of the bulb, and greatly reduces the assembling difficulty of the LED lighting assembly according to the present disclosure.
"Preferably, the bulb is made from a glass or a plastic. Of course, the bulb also may be made from other transparent or semi-transparent materials suitable as a bulb.
"According to various embodiments, the LED retrofit lamp has a lamp holder and the LED lighting assembly as described above, wherein the lamp holder is fixed on the heat sink of the LED lighting assembly to connect the LED lighting assembly to the power supply. Such LED retrofit lamp is characterized by good light intensity distribution performance, a high inner space utilization ratio and simple structure, and is easily manufactured.
BRIEF DESCRIPTION OF THE DRAWINGS
"In the drawings, like reference characters generally refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the disclosed embodiments. In the following description, various embodiments described with reference to the following drawings, in which:
"FIG. 1 is a sectional view of an LED retrofit lamp according to the present disclosure;
"FIG. 2 is a schematic diagram of a bulb of an LED lighting assembly according to the present disclosure;
"FIG. 3 is a light path map of reflection of light in a bulb;
"FIG. 4A-FIG. 4C are curve diagrams of light intensity of the LED lighting assembly according to the present disclosure; and
"FIG. 5A-FIG. 5B are sectional views of alternative embodiments of a bulb."
For additional information on this patent application, see: Zhang, Qihui; Ming, Yusheng; Li, Anmiao; Buchhauser, Dirk.
Keywords for this news article include:
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