In 1968, the HP company produced red LED light (wavelength 660nm), and then appeared yellow-green (wavelength 570nm), blue (wavelength 470nm) and pure green (wavelength 525nm) that can be used for display screens. Bright blue and pure green semiconductor wafer manufacturing technology is mainly in the hands of a few companies in Japan and the United States, resulting in relatively expensive prices.
The LED luminescent materials used in the display have the following forms:
①LED light (or single light)
It is generally composed of a single LED chip, a reflective bowl, a metal anode, and a metal cathode, and is covered with an epoxy resin shell with light-transmitting and light-concentrating capabilities. One or more (different colors) single lights can be used to form a basic pixel. Due to the high brightness, it is mostly used for outdoor display screens.
②LED dot matrix module
The light-emitting matrix is ??composed of several chips, and is encapsulated in a plastic shell with epoxy resin. Suitable for row and column scan drive, it is easy to form a high-density display, which is mostly used for indoor display.
③SMD LED light (or SMDLED)
It is a package of LED luminescent lamp in the form of soldering, which can be used for indoor full-color display, can achieve single-point maintenance, and effectively overcome the mosaic phenomenon.