LED

 What is LED?

LED stands for Light Emitting Diode, a kind of semiconductor which is used to give and receive the electronic signal into infrared rays or light, using the characteristics of compound semiconductor. This is used for household appliances, remote controller, electric bulletin board, various kinds of automation appliances.


• Infrared LED Chip
  Stands for IRED(Infrared Emitting Diode) Chip. The manufactured chip is used for IR Emitter, TV remote controller, optical switch, IR LAN, and for a module for wireless digital data communication.
  
  
• Visible LED Chip
  Stands for VLED (Visible Light Emitting Diode) Chip, whose color covers red, green and orange etc. This chip is assembled into lamp to be used for light source of indication or signal of various electric products .

 Semiconductor used for LED

• General Level

  GaP GaN GaAs GaAIAs Green, Red Blue Red, Infrared Red, Infrared

• Super Level

  GaAIAs GaAsP GaN InGaN GaP Red Red, Yellow Blue Green Green

• Ultra Level

  GaAIAs InGaAIP GaN InGaN Red Yellow, Orange, Red Blue Green

 Color of LED by wavelengths

LED is divided into General level, Super level, Ultra level, depending on the curving angle. 100mcd and under belongs to General level, 500mcd and under belonging to Super level, and 500mcd and over belongs to Ultra level.


• General Level

  400 ~ 450 450 ~ 470 470 ~ 557 557 ~ 567 567 ~ 572 572 ~ 585 585 ~ 605 605 ~ 630 630 ~ 700 Pure Blue General Blue Pure Green General Green Yellow Green General Yellow General Amber General Orange General Red

• Super Level

  470 572 650 660 Super Blue Super Yellow Green Super Red Super Red

• Ultra Level

  591 610 624 639 660 Ultra Yellow Ultra Amber Ultra Orange Ultra Red Ultra Red

 LED production process

• In-line process
  In-line processing consists of die bonding process and wire bonding process. These two processes are made automatically by automatic image recognition system. In die bonding process, it is important to place the chip on silver epoxy already spread on the center of the lead frame cup with proper pressure, on the other hand in wire bonding process, it is important to bond gold wire with electrode of the upper side of semiconductor and lead frame of one side with proper pressure to connect.
  
  
• Mold process
  Mold process is a process where the lead frame with the chip bonded is molded into epoxy. LED lamp is completed when idiomorph is spread automatically and the lead frame is soaked in the mold cup where epoxy is soaked, finally to be hardened in the electric oven.
  
  
• Test and classification process
  A process where of the electric and optical characteristics of LED are measured to classify depending on the performances.
  
  
• Tapping process
  A process where the LED lamp is formed and attached on the tape so that it can be used for the automatic inserter which allows electric devices to be inserted into the PCB board automatically.

 Outlook for LED industry

LED has a lot of advantages due to the property of semiconductor in terms of processing speed, power consumption, and durability, favored as electronic indication devices. Besides, it has a good possibility of replacing lighting apparatus as the products with high brightness produced.

LED is widely used as various kinds of indicating devices as it is not blinding, without short circuit of its filament unlike conventional electric lamps, being manufactured small. Its semi-permanent durability (one million hours or so) is another advantage. Especially as the full color of LED is possible due to the general use of blue LED, with lowered prices, the prospect for its use is in good shape.