According to the luminous color of LED, it can be divided into red, orange, green (yellow-green, standard green and pure green) and blue light. In addition, some LEDs contain chips of two or three colors.

According to whether light-emitting diodes are doped with scatterers, colored or colorless, light-emitting diodes of the above colors can be divided into four types: colored transparent, colorless transparent, colored scattering and colorless scattering. Scattering LEDs and LEDs are used as indicator lights.

Secondly, the LED lamps are classified according to the characteristics of the luminous surface of the LED.

According to the characteristics of light-emitting surface of LED, it can be divided into round lamp, square lamp, rectangle, surface LED, side tube and microtubule for surface mounting. The diameter of circular lamp is divided into φ2mm, φ4.4mm, φ5mm, φ8mm, φ 10mm and φ20mm. In foreign countries, light-emitting diodes with a diameter of 3 mm are usually marked as T-1; φ5mm is marked as t-1(3/4); Write φ4.4mm as T- 1( 1/4).

The angular distribution of circular light intensity can be estimated by half-value angle.

From the angle distribution diagram of luminous intensity, there are three types:

(1) high directivity. Generally, it is a pointed epoxy package or a package with a metal reflective cavity, and no scattering agent is added. The half-value angle is 5 ~ 20 or less, which has high directivity and can be used as a local lighting source or combined with a photodetector to form an automatic detection system.

(2) standard type. Usually used as an indicator light, its half-value angle is 20 ~ 45.

(3) Scattering type. This is an indicator lamp with a large viewing angle, with a half-value angle above 45 ~ 90, and a large number of scattering agents.

Third, according to the structure of LED

According to the structure of LED, there are full epoxy package, metal-based epoxy package, ceramic-based epoxy package and glass package.

4, according to the luminous intensity and working current

According to the luminous intensity and working current, there are LEDs with ordinary brightness (luminous intensity100 MCD); Luminous intensity between 10 and 100 MCD is called high brightness led. Generally, the working current of LED is in the range of ten milliamps to tens of milliamps, while the working current of low-current LED is below 2mA (the brightness is the same as that of ordinary LED).