Method for mounting light-emitting elements
In a first aspect of the present invention, it is suggested that a mounting method for mounting light-emitting elements as evenly as possible in a mounting area of a lighting device may permit increased number of light-emitting elements. In a second aspect of the present invention, a lighting device including a substrate with a circular mounting area, a plurality of light-emitting elements configured to be positioned at centers of equal smaller circular areas that are calculated to be equal in size in the circular mounting area, the equal smaller circular areas being equal in size to each other and set as large as possible without an overlapping portion in the circular mounting area, a total area of the equal smaller circular areas being smaller than the circular mounting area, and the light-emitting elements and the equal smaller circular areas being the same in number is suggested.
1. A mounting method for mounting N light-emitting elements in a circular mounting area provided on a substrate of a lighting device, the method comprising:
setting the circular mounting area of radius R on the substrate which is surrounded by an enclosure frame;
setting N smaller circular areas each with radius of r, wherein radius r is the maximum radius that allows the N smaller circular areas to be maximized and to be all contained inside the circular mounting area of radius R without an overlapping portion of the N smaller circular areas on the basis of the theory of close packing of circles;
mounting the N light-emitting elements at the substrate to be positioned at the center positions of the N smaller circular areas; and
electrically connecting the N light-emitting elements with electrodes, which are arranged around the mounting area on the substrate, by wire bonding; and
filling a sealing resin, which includes phosphor materials, within the enclosure frame in order to seal the N light-emitting elements therein and create a light emitting area,
wherein the N smaller circular areas are set with a packing ratio d of the N smaller circular areas in the mounting area to be 75% or higher, and N is an integer of 38 or more, and
wherein smaller circular areas positioned at the outermost periphery of the N smaller circular areas inside the mounting area are set in contact with a circumferential edge defining the mounting area.
2. The mounting method for mounting light-emitting elements according to claim 1 , wherein the mounting area of the substrate comprises an insulating white-colored reflection layer.
3. The mounting method for mounting light-emitting elements according to claim 1 , wherein the mounting area is set to be an insulation treatment given to a metal base of aluminum.
4. The mounting method for mounting light-emitting elements according to claim 1 , further comprising tracing the N smaller circular areas on the circular mounting area of radius R.
5. The mounting method for mounting light-emitting elements according to claim 1 , wherein mounting the N light-emitting elements at the substrate to be positioned at the center positions of the N smaller circular areas comprises mounting and adhering the light-emitting elements.