The design of PC LEDs, or phosphor-converted LEDs
In general, surface-mount PLCC type packages are used for mid-power LEDs. PLCC, or plastic leaded chip carrier, is an abbreviation. One or more semiconductor chips (or dies) are bonded or soldered onto a lead frame to create a surface-mount device (SMD). The lead frame, which is intended to provide electrical connection, thermal dissipation, and light reflection for the LED die, is built of a copper alloy or a nickel iron alloy. To increase electrical conductivity and offer high light reflection, it is plated with silver, gold, or other metals. Wire bonding is used to link the anode and cathode leads to the positive and negative electrodes of the LED die, respectively. Because most mid-power LEDs are constructed with anode and cathode pads on the base of the package rather than the conventional leads produced along the perimeter, modern mid-power LEDs are also known as Quad Flat No-lead (QFN) packages. The lead frame is molded in a plastic housing during the last step of packaging, creating a hollow. The epoxy resin or silicone-based polymer utilized to fill the cavity serves as the phosphor encapsulation matrix. There are many different form factors for SMD LEDs. The most widely used sizes are 2835 (3.5 x 2.8 mm) and 3030 (3.0 x 3.0 mm), with other sizes like 5630 (5.6 x 3.0 mm) and 3014 (3.0 x 1.4 mm) being utilized in specialized applications.
