1. Overview

Light Emitting Diodes (LEDs) are semiconductor devices that convert electrical energy into light. The categories of infrared (IR), ultraviolet (UV), and visible LEDs are differentiated by their emission wavelengths. These devices play critical roles in modern technology, enabling applications from communication systems to medical diagnostics, with advantages including energy efficiency, compact size, and long operational lifetimes.

2. Main Types and Functional Classification

3. Structure and Composition

LED emitters typically consist of: - Die: Semiconductor material (e.g., GaAs for IR, AlGaN for UV, InGaN for visible) - Substrate: Sapphire or silicon carbide for mechanical support - Encapsulation: Epoxy or silicone lens for light extraction and protection - Contact Layers: Metal electrodes for electrical connection - Thermal Pad: For heat dissipation in high-power devices

4. Key Technical Specifications

5. Application Fields

Major industries include: - Consumer Electronics: Smartphones (proximity sensors), TVs (backlighting) - Healthcare: Pulse oximeters (IR), sterilization equipment (UV) - Industrial: Machine vision systems (visible), chemical detection (UV) - Security: Surveillance cameras (IR), document authentication (UV) - Automotive: Brake lights (visible), LiDAR systems (IR)

6. Leading Manufacturers and Products

7. Selection Recommendations

Key factors include: - Spectral matching to target application (e.g., 280-320 nm for DNA analysis) - Thermal management requirements (e.g., heatsinks for >1 W devices) - Environmental conditions (e.g., IP67 rating for outdoor use) - Cost vs. performance tradeoffs (e.g., high-efficiency UV LEDs for sterilization) - Compatibility with drive electronics (current/voltage specifications)

8. Industry Trends

Emerging developments: - Miniaturization for wearable devices (e.g., sub-1 mm IR LEDs) - Increased UV-C efficiency (targeting 10% wall-plug efficiency) - Integration with IoT systems (smart lighting networks) - Advancements in phosphor conversion for visible LEDs - Wide bandgap semiconductor adoption (GaN-on-SiC substrates) - Environmental regulations driving mercury-free UV solutions