2000 yen LED bulb listed

In June 2009, Sharp launched LED bulbs with a price of around 4,000 yen. Companies competed to follow each other and promoted low prices at one stroke. After only a half year or so in December 2009, LED bulbs with a price of only about 2,000 yen were listed one after another.

One of them is the "Luminous" series (hereinafter referred to as Luminous bulbs) jointly developed by Doshisha and Orion Electric (Headquarters: Echizen City, Fukui Prefecture) and listed on December 14, 2009 (Fig. 1(a). ). The power consumption is 6.6W, the total luminous flux is 420lm (white), the equivalent of 60W incandescent lamp is 2480 yen (tax included), the power consumption is 4.7W, the total luminous flux is 310lm (white), The equivalent of a 40W incandescent lamp is priced at 1980 yen (tax included). In December 22nd, Otsuka Chamber of Commerce listed the "Lumidas-CL" series of LED bulbs developed by Korea FAWOO Technology for 2,380 yen (tax included) (Fig. 1(b)). This series includes products that consume 5W of electricity and have a total luminous flux of 292lm (white) instead of 20~30W incandescent lamps.

In the "Luminous bulb" co-developed by Donovan Electric and Doshisha, the price of a 40W incandescent lamp was 1,980 yen, which substantially reduced the price (a). The LED bulb "Lumidas-CL" produced by the Osaka Industrial Complex, which is marketed by FAWOO Technology of Korea, is characterized in that it adopts an elongated shape and dissipates heat from the inside of a vent hole penetrating through the central portion of the heat sink (b).

Equipped with dozens of LED packages

The key to realizing the low price of Luminous light bulbs with the aim of advancing development at a target of 1980 yen (Doshisha Lifestyle Business Unit, Lifestyle Products Minister and Director of Mines) is that the light bulbs are equipped with many small LED packages (Figure 2). The equivalent of 60W incandescent lamps is equipped with 40 LED packages, and the equivalent of 40W incandescent lamps is equipped with 34 LED packages.

In the past, many manufacturers used LED packages with input power of 1W in LED bulbs. The Luminous bulb is equipped with a hundred and a few dozen mW LED packages. Although there is an increase in the number of packages that need to be equipped, "to reduce the total cost of LED packages" (Doshisha). However, to install a large number of LED packages, it is difficult to reduce the area of ​​the mounting base plate. For many of these manufacturers in order to adapt the LED light bulbs to existing lighting fixtures, the diameter of the LED bulbs is controlled to be less than 60mm, which is the same as that of incandescent lamps, but the Luminous bulbs have been increased by 4mm to 64mm.

In the equivalent of 60W incandescent lamps, 40 small LED packages are installed. The heat of the mounting base plate can be transmitted to the heat sink via the metal plate.

The use of small LED packages also helps improve heat dissipation. Since the small heat source is dispersed on the LED board, there is no place where the concentration of temperature rises, and the temperature of the board easily becomes uniform.

Luminous bulbs' LED mounting bases use metal baseplates in products that are equivalent to 60W incandescent lamps, and resin baseplates rather than metal baseplates are used in products equivalent to 40W incandescent lamps. “Although the thermal conductivity is excellent, there is no need to use the more expensive metal backplanes (Doshisha) in products that have less LED packages and less heat. The equivalent of a 40W incandescent lamp uses a low-cost substrate that also makes a significant contribution to the price of less than 2,000 yen.

Ring configuration LED

Lumidas-CL also uses a large number of methods with a small LED package just like Luminous bulbs. The number of equipment is 20. In addition, a low-cost structure considering ease of assembly has also been adopted. For example, a snap-fitting (SnapFit) is used in the assembly of the resin case, and the connection between the LED mounting board, the power supply circuit board, and the lamp socket is made by soldering. Methods. In addition, the Korean LED lighting safety standard certification has been obtained.

A three-layer structure of a lens, a mirror, and a heat sink, respectively, from the outside is used as the hollow shape with a narrowed tip. The LED package is mounted on an annular bottom plate and then mounted at the base of the heat sink.

The appearance of the slender shape is unique, at first glance will feel that there is no heat sink, but in fact the heat sink is embedded in the central part of the bulb (Figure 3). A three-layer structure consisting of a lens, a mirror, and a heat sink, respectively, from the outside is used, and an annular LED mounting base plate is attached to the base of the heat sink (near the base).

The surface of the lens has holes, and air can enter and exit between the through holes in the central part of the heat sink and the outside. In other words, Lumidas-CL employs a structure that dissipates heat from the inside of the through hole of the heat sink. In addition, in order to facilitate the circulation of air, a notch is provided in the bottom plate of the power supply circuit arranged below the heat sink, and a slit is provided in the resin case under the bulb. In this way, air can circulate up and down inside the bulb.