Toshiba lighting and SHARP new LED bulb interior structure

With light emitting diode (LED) as the light source lighting device with the characteristics of low power consumption, long life gradually began to penetrate in the market. Among them, the desire to replace incandescent bulbs, light bulbs and other traditional fluorescent lamp bulb type LED lighting (hereinafter referred to as LED bulbs) is more concerned recently. Because in accordance with the calculation of the LED life of the bulb unit price has been the same as the traditional light bulb, so it is expected to accelerate the popularity of ordinary families.

The first low-cost LED light bulb manufacturers are SHARP. SHARP announced on June 11, 2009, the company will be the actual price of less than 4000 yen as a selling point to enter the LED bulb market. The price setting is very striking, about half the price of the LED light bulb. In March 2009 LED started selling Toshiba lighting (Toshiba Lighting) to make a quick response to SHARP products released after 11 days, which was released in June 22nd and SHARP in July 15th with the listing of new low-cost LED lighting products *1, *2.

Figure 1: low cost LED bulb Toshiba lighting and SHARP have been listed on the price of about half of the previous, that is, the price of less than 4000 of the price of ordinary light bulb type LED lighting (LED bulb). In order to prevent the luminous efficiency is reduced, the life is shortened, the LED heat dissipation is very important. Therefore, the lower part of the LED bulb is a radiator made of aluminum alloy castings.

The lower part of the bulb is a radiating part

Low price does not mean that LED bulbs can abandon the low power consumption, long life and other unique advantages. Moreover, the product to be based on the market, but also need to have a higher heat capacity.

LED light emitted by the light bulb infrared component less. Therefore, compared with incandescent bulbs, bulb type fluorescent lamp, light irradiation part of the slow heating *3. But LED itself will heat, so the heat is indispensable. Once more than the allowable temperature of the LED chip, the luminous efficiency of the LED will decline, the life of the bulb will have a negative impact.

From an external point of view, the characteristics of LED bulbs can be said to improve the results of heat dissipation. Look at the LED bulb from the side, the lower side of the whole side of the radiator (Figure 1). Toshiba lighting, SHARP are made of aluminum alloy radiator.

Comparison of the two radiators, in addition to color, shape differences are also very obvious. In terms of height, although SHARP products slightly more, but the heat sink area is greater than the Toshiba lighting. Toshiba lighting products channel depth from bottom to top gradually increased, while SHARP is up and down the basic high.

The larger the surface area, the higher the heat dissipation performance. In the case of limited size, increasing the depth of the channel is one of the ways to increase the surface area, but with the increase in the depth of the channel, the power circuit board, resin shell and other internal installation space will be reduced by *4.

The internal space of the radiator for Toshiba lighting is cylindrical, and the SHARP product is close to the conical shape (Figure 2). While maintaining the insulation, the power supply circuit board is installed on the bulb shell.

The main structure of figure 2:LED Toshiba lighting LED lamp radiator (shell) of the cylinder side 16 right angled triangle trench, cover plate. Above directly fixed LED substrate. The power supply circuit board is fixed in the cup-shaped resin shell. On the other hand, SHARP LED bulb radiator has a taper cylinder shape, the surface is installed with 60 pieces of less than a few mm blades. The LED substrate is fixed on the circular plate on the top of the radiator. The power circuit board is fixed on the upper side of the radiator, which is inserted into the conical (but most of the side surface) resin shell A.

The LED chip is the largest source of heat for the LED bulb, which is packaged in a plurality of LED chips, and then mounted on a substrate made of aluminum alloy. The LED substrate of the aluminum alloy is fixed on the upper part of the radiator. SHARP products, LED substrate and heat sink also sandwiched between the metal plate.

This article will combine Toshiba lighting products and SHARP products LED light bulbs, detailing its internal structure.

*1: SHARP initially scheduled for July 15, 2009. But in July 9th the company issued a decision to postpone the listing because it is "beyond expectations". Support dimmer, equipped with dimming / toning function of LED bulbs will be the same year in September 1st, other LED bulbs will be listed in the same year in August 1st.

*2: bulb giant Panasonic, although in March 2009 held the "Lighting Fair 2009" Exhibition on the light bulb LED reference, but as of early August 2009, the company has not yet put into production specific plans".

*3:LED lamp light in the ultraviolet region of the composition is relatively small, so also has not attracted the advantages of UV sensitive insects.

*4: to increase the surface area of the blade height, or to reduce the blade spacing (increase the number of slices). Toshiba lighting refers to the flow of air around the radiator (convection) when determining the spacing and height of the blades.