Toshiba and SHARP new LED light bulb (two): radiator structure

The connection structure of the radiator is different

The hemispherical part of the diffused LED light is called a spherical lampshade". The spherical lampshade of Toshiba lighting is made of polycarbonate, which is fixed on the 4 position above the radiator. The spherical bulb is usually made of glass. This is because LED light is not easy to heat, so can use resin. Moreover, when the resin is used, the bulb is not easy to break when the bulb is dropped, and the safety is improved.

The lower part of the spherical lampshade is provided with a LED substrate. In Toshiba lighting products, 6.9W (white, total luminous flux 565lm) rated power consumption of products, LED substrate on the LED package number of 7 (Figure 3) *5.

Figure 3: LED upper backside of the substrate and the radiator Toshiba lighting LED lamp (shell) on the contact surface, the direct use of 2 screws.

A connector for connecting a power supply circuit line is installed on a LED substrate of Toshiba lighting. The connector is a product that does not need to be welded, and the simplicity of assembly is estimated. In addition, Toshiba's LED bulb is assembled in a Japanese factory.

The LED substrate is fixed by 2 screws, and the upper surface of the radiator can be seen after the substrate is removed. In this part, the planarization of the LED substrate is carried out by means of mechanical machining, and the substrate can be fully attached to the back of the substrate so as to obtain the thermal conductivity.

SHARP's LED light bulb is made of glass *6. 7.5W (daylight, total luminous flux 560lm) rated power consumption products on the LED substrate are equipped with 6 LED packages (Figure 4). The wiring between the circuit board of the power supply is connected by welding.

Figure 4: SHARP LED bulb upper LED substrate using 3 screws fixed on the metal plate, between the two is coated with heat conducting oil. In addition, the wiring of the power circuit board is welded.

The LED substrate by 3 screws fixed on the metal plate, between the two is coated with thermal grease (Grease). Fixed LED substrate is not made of aluminum alloy casting radiator, but another metal plate. Although the material is aluminum alloy, but the surface can not see traces of machining. This metal plate LED substrate, the application performance may not be sufficient, so need to use thermal grease.

The metal plate is fixed on the radiator by using 3 screws (not fixing the screws of the LED substrate). Remove the metal plate to see that the radiator is filled with black resin (Figure 5) *7. The estimation of these resin fillings to promote heat conduction, but on the back of these resin and the metal plate does not contact, so that its main purpose is to transfer power supply circuit board heat radiator, rather than the heat emitted by the LED package.

Figure 5: internal metal plate SHARP LED bulb with 3 screws fixed on the radiator (shell). The radiator is filled with the filling material, but is not contacted with the back of the metal plate, and the heat can only be transmitted through the contact part of the metal plate and the radiator. In addition, there is a O ring between the two, to ensure the tightness.

The contact part of the radiator and the metal plate is annular, and the area is not large. The contact part of the back surface of the metal plate is provided with a circle of flanges, which is not only easy to be positioned when assembled, but also slightly expands the contact area. In addition, the external metal plate is exposed to the light bulb, a bulb design decoration.

Configuration of the metal plate and the surrounding part of the radiator contact O ring is not available. If it is to maintain the tightness, then the role of the ring should be to prevent the leakage of liquid resin filled material, to prevent the water from the outside. It is also one of the purposes to promote heat transfer from the metal plate to the radiator. (to be continued, "the" dismantling group)

*5: Toshiba lighting 4.1W (white, total luminous flux 340lm) LED bulb is equipped with 4 LED packages.

*6: the inner surface of the glass is coated with a light scattering coating, which can change the direction of the LED light into uniform surface light.

*7: SHARP LED bulbs, dismantling products (rated power consumption of 7.5W products) heavy 158g, 4.1W product weight 118g. It can be inferred that there may be differences between components and internal structures.