LED knowledge: How many types of LEDs can be divided into

LED stands for Light Emitting Diode. This semiconductor device comes in various types depending on its properties and applications:

1. By Luminous Color:

Based on the color of the emitted light, LEDs can be categorized into several groups: red, orange, green (which can further be subdivided into yellow-green, standard green, and pure green), blue, and white light. Additionally, some LEDs consist of multiple colored chips, allowing them to emit different hues simultaneously.

The various-colored LEDs can also be grouped based on their transparency and scattering properties: colored transparent, colorless transparent, colored scattering, and colorless scattering. The scatter-type LEDs are often used as indicator lights.

In general, LED displays commonly utilize red, green, and blue LEDs. For lighting purposes, however, white LEDs are more frequently employed.

2. By Light-Emitting Surface Characteristics:

LEDs can also be classified by the shape and characteristics of their light-emitting surfaces. These include round, square, rectangular, surface-mount, side-emitting, and surface-mounted micro LEDs. Round LEDs are available in sizes like φ2mm, φ4.4mm, φ5mm, φ8mm, φ10mm, and φ20mm. Internationally, a φ3mm LED is typically called T-1, φ5mm is T-1 (3/4), and φ4.4mm is T-1 (1/4).

From the perspective of angular light intensity distribution, LEDs can be divided into three categories:

(1) Highly directional. These are usually epoxy-packaged with a pointed tip or a metal reflector case and lack scattering agents. Their half-angle is 5°-20° or less, providing strong directionality, suitable for localized illumination or combined with detectors to create automated systems.

(2) Standard type. Often used as indicator lights, their half-angle ranges from 20° to 45°.

(3) Scattering type. These have a wide viewing angle with a half-angle of 45° to 90° or more, containing a significant amount of scattering agents, making them ideal for general-purpose indicators.

3. By Structure:

LEDs vary structurally as well. They can be fully epoxy-sealed, mounted on a metal base with epoxy, built on a ceramic base with epoxy, or encased in glass.

4. By Luminous Intensity and Operating Current:

Standard brightness LEDs typically have a luminous intensity under 100mcd and operate at currents between 10mA and tens of milliamps. High-intensity LEDs have a luminous intensity ranging between 10 and 100mcd. Low-current LEDs, on the other hand, operate at currents below 2mA but still maintain similar brightness levels as standard LEDs.

LED technology continues to evolve rapidly, offering new possibilities in both display and lighting solutions. Its versatility makes it a key player in modern electronics, from consumer gadgets to advanced industrial applications.