(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° to 20° or less, and the rectifier bridge has high directivity, which can be used as a local illumination light source, or combined with a light detector to form an automatic detection system.

(2) Standard type. It is usually used as an indicator light, and its half-value angle is 20° to 45°.

(3) Scattering type. This is an indicator light with a larger viewing angle, a half-value angle of 45° to 90° or more, and a larger amount of scattering agent.

LED light-emitting diodes are divided by current

According to the luminous intensity and working current, there are LEDs with ordinary brightness (luminous intensity of 100mcd); those with luminous intensity between 10 and 100mcd are called high-brightness light-emitting diodes. Generally, the working current of chip diodes is in the range of tens of mA to tens of mA, while the working current of low-current LEDs is below 2 mA (the brightness is the same as that of ordinary light-emitting tubes)