What are LED filaments?

LED filaments are an innovative technology, where a normal 3.0 V LED chip is adhered inside a leadframe cup with epoxy, and dispensers are used in the packaging process to make PLCC packages. LED filaments basically comprise of many LED chips placed next to each other in a series connection onto a glass substrate, and then are compressed into LED packages. The LED luminaires possess low current and high voltage features, which effectively lowers LED thermal dissipation and driver costs, giving it a competitive edge.

These LED filaments are a new type of LED packaging, and one of the most popular on the market because it can be used to make LED E27 bulbs similar to incandescent bulbs, which can easily achieve omnidirectional 360 degree lighting.

LED filaments usually are made with 28 pieces of 1016 LEDs that are 0.02W, these LED chips use series connection to be placed on sapphire substrates that are 38 mm long and 1.5 mm wide, before it is coated with phosphor. LED filaments tend to use 10 mA electric current to drive the devices, and use 84V and have a luminous efficiency of 0.84W and light output of 100 lm. The LEDs lumen efficiency can reach 120 lm/W, and combined with red LED chips the CRI can reach above 95, and possess excellent optoelectronic features.

By using LED filaments the companies can make small to mid-power LED bulbs or candle lights that usually comprise of four LED filaments. The filaments can be arranged in two series connections or two parallel connections to reach the power output of 3.6W LED bulb or LED candle light, or reach 400 lm luminous output that can be used to replace 40W incandescent bulbs.

Incandescent bulb manufacturers can use current technology and production lines to make LED filament bulbs, which use existing incandescent bulb glass leadframe designs to connect the LED filaments. By using special highly transmissivity incandescent bulb technology and automatic glass bulb blowing technology to make incandescent LED bulbs with high C/P ratio.