Surface Mount Package

In 2002, surface mount package LED (SMD LED) gradually market acceptance and market share from pin package steering SMD meet the entire electronics industry development trend, many manufacturers launched such products.

Most of the early SMD LED with transparent plastic body SOT-23 Improved, Dimensions 3.04 x 1.11mm and-reel packaging container Taping. SLM-125 series of high-brightness SMD with lens, SLM-245 series LED, the former for monochromatic light, which is for two-color or three-color light-emitting, developed on the basis of the SOT-23. , SMD LED in recent years become a development hot spot, a good solution to issues such as brightness, viewing angle, flatness, reliability, consistency, using the lighter PCB board and reflective layer materials, the need to fill in the reflective layer less epoxy resin, and to remove heavier carbon steel materials pin, by reducing size and weight, can easily reduce the product weight in half, eventually apply more perfect, especially suitable for indoor, semi-outdoor full color display applications.

Common SMD LED in several dimensions, and calculated according to the size (plus the necessary clearance) the viewing distance. Its cooling pad is an important channel for SMD LED vendor data are based on 4.0 × 4.0mm pads can be designed using the reflow soldering pads and pins equal. High brightness LED products can be used PLCC (Plastic Leaded Chip Carrier) -2 package, the external dimensions of 3.0 × 2.8mm, through the unique method of assembling high-brightness die thermal resistance of 400K / W, according to the CECC way welding, its luminous intensity at 50mA drive current issued 1250mcd. Seven-segment one, two, three and four digital SMD LED display character height of 5.08-12.7mm, wide display size choice. PLCC package to avoid the pin seven segment digital display manually insert the pin alignment process, in accordance with automatic pickup - mount equipment production requirements, flexible application design space to display a clear and bright. Multicolor PLCC package with an external reflector can be easily combined with light-emitting tube or light guide, reflective type alternative current transmission type optical design to provide uniform lighting for a wide range of regional R & D at 3.5V, 1A driver work under conditions of power SMD LED package.

Power-type package

LED chip and packaging to the direction of the high-power development, large current than Φ5mmLED 10-20 times luminous flux, we must adopt effective heat dissipation and packaging material deterioration solve the problem of bad light, shell and tube, and the package is the key LED packaging technology, can withstand the power of the number of W. 5W series of white, green, blue-green, blue power LED from early 2003 to supply and white LED light output up to 1871m 44.31m / W luminous efficiency green light decay, to develop affordable 10W power LED large area pipe; dagger size of 2.5 × 2.5mm, 5A current, the light output of up to 2001m, as solid-state lighting source development space.

Luxeon series power LED A1GalnN power-type flip-die flip chip bonding silicon carrier solder bump, and then complete flip chip bonding of silicon carrier loaded heat sink shell and tube, and the bonded lead encapsulation. This package for light extraction efficiency, thermal performance, are designed to increase the operating current density. Its main features are: low thermal resistance, generally only 14 ° C / W, the only conventional LED 1/10; may * package filled with stable flexible gel, in the range of -40-120 ℃ will not drastic temperature change and the internal stress generated by the gold wire is disconnected from the lead frame, and to prevent yellowing of the epoxy lens, the lead frame due to oxidation does not tarnish; reflector cup and the optimal design of the lens so that the radiation pattern is controllable and the highest optical efficiency. In addition, the performance of the output optical power, external quantum efficiency, the development of LED solid-state light source to a new level.

Norlux series power LED package structure for a combination of multi-chip of hexagonal aluminum plate for the base (so that it does not conductive), base diameter of 31.75mm, light-emitting area is located in the central part of about (0.375 x 25.4) mm diameter can accommodate 40 LED die, aluminum as a heat sink. The ultrahigh brightness produced by the bonding wire through the die base of the two points of contact with the positive and negative connections, according to the size of the desired output optical power to determine the number of base Ordering die, can be combined package AlGaInN and AlGaInP die, the emitted light were monochrome, color, or a synthetic white, enclosing with a high refractive index material by the shape of the optical design. This package is a combination of high-density packaging of the conventional tube core, the light extraction efficiency is high, low thermal resistance, and better protect the pipe core and the bonding wire, under a large current has a higher optical output power, is also a promising development LED solid-state light source.

In the application, can be encapsulated product assembled in the PCB board, with an aluminum core metal sandwich forming power density LED PCB plate as the device electrodes connected with wiring, the aluminum sandwich can be made to the heat sink using obtained The higher luminous flux and photoelectric conversion efficiency. In addition, good package SMD LEDs are small, can be flexibly combined, constitute a module type light guide plate-type condenser type, reflective type colorful lighting source.

Power type LED thermal characteristics directly affect the LED's operating temperature, luminous efficiency, emission wavelength, life, power type LED chip package design, manufacturing technology is particularly important.

The LED Development and application prospects

In recent years, LED luminous efficiency increased 100 times, costs decreased by 10 times, is widely used in large-area graphic display full-color screen status indication, sign lighting, signal displays, liquid crystal display backlighting, automotive combination taillights car lighting, etc., its development prospects to attract the global lighting large manufacturers have joined the LED light source and market development. Development and application prospects are very white LED, significant economic used as solid-state lighting devices, and environmentally-friendly, and is gradually replacing the traditional incandescent World annual growth rate of more than 20%, the United States, Japan, Europe and China Taiwan Province have launched a semiconductor lighting plan. Ordinary white LED luminous efficiency 251m / W, experts predict that 2005 may exceed 3001m / W. Excellent heat dissipation characteristics and optical properties of power type LED general lighting can adapt, academia and industry that is the only way of LEDs into the lighting market. To replace fluorescent lamps, white LED must have 150-2001m / W luminous efficiency, and Im price should be significantly lower than 0.015/Im (the current price of about 0.25 $ / Im, red LED for 0.065/Im) To achieve this goal there are many technical issues need to be studied, but to overcome to solve these problems is not very distant. LED luminous efficiency of light-emitting solid principles of physics, can approximate 100% LED known as the 21st century and the new light source, is expected to become the fourth-generation light source Following incandescent, fluorescent, high-intensity gas discharge lamp.