Overview
IEC 60747-5-8:2019 is an international standard developed by the International Electrotechnical Commission (IEC) that defines the test methods and terminology for determining various optoelectronic efficiencies of single light emitting diode (LED) chips or packages without phosphor. The standard ensures uniform methodology for evaluating the performance of optoelectronic devices, specifically excluding white LEDs intended for general lighting applications.
The standard covers measurement and reporting procedures for the following key efficiencies of LEDs:
- Power efficiency (PE)
- External quantum efficiency (EQE)
- Voltage efficiency (VE)
- Light extraction efficiency (LEE)
It also provides standardized definitions for injection efficiency (IE) and radiative efficiency (RE). For the measurement of LEE, reference is made to internal quantum efficiency (IQE) as detailed in IEC 60747-5-9 and IEC 60747-5-10.
Key Topics
Optoelectronic Efficiency Definitions
- Power Efficiency (PE): Ratio of radiant power output to input electrical power, indicating how effectively the LED converts electric input into emitted light.
- External Quantum Efficiency (EQE): Ratio of photons emitted into free space to electrons passing through the device, reflecting the device's photon generation effectiveness.
- Voltage Efficiency (VE): Ratio of mean photon energy to the energy supplied by the LED’s forward voltage, providing insight into energy transfer during emission.
- Light Extraction Efficiency (LEE): Ratio of photons emitted into free space to those generated in the active region, representing the effectiveness of light extraction.
- Internal Quantum Efficiency (IQE): Detailed in related standards, necessary for calculating LEE.
Test Methods and Measurement Sequence
- Standardized environmental conditions for testing (temperature, humidity).
- Stepwise procedures for measuring each efficiency, starting from radiant power and voltage measurement to spectral distribution and photon energy calculations.
- Use of standardized equipment as referenced in IEC 60747-5-6.
Test Reporting
- Comprehensive test reports including device data (maker, model, chip size), operating and test conditions, and all measured efficiency values.
Applications
IEC 60747-5-8:2019 is critical for:
- LED Manufacturers: Provides repeatable and comparable methods to evaluate and benchmark efficiency of non-phosphor LEDs, important for product development and quality control.
- Testing Laboratories: Facilitates precise and standardized LED efficiency measurements for certification, R&D, and compliance to international requirements.
- Component Sourcing and Specification: Enables design engineers to reliably compare device performance based on standardized data.
- Quality Assurance and Procurement: Ensures that purchased LED chips meet relevant efficiency standards.
These test methods are suited for a variety of optoelectronic LED applications in display, indicator, sensor, communication, and other non-lighting sectors where precise optoelectronic efficiency data is vital.
Related Standards
Those applying IEC 60747-5-8:2019 should also refer to related standards within the IEC 60747 series, including:
- IEC 60747-5-6: Semiconductor devices – Optoelectronic devices – Light emitting diodes (general test methods).
- IEC 60747-5-9: Test method of the internal quantum efficiency based on temperature-dependent electroluminescence.
- IEC 60747-5-10: Test method of the internal quantum efficiency based on room-temperature reference point.
- IEC 60050-845: International Electrotechnical Vocabulary – Lighting.
IEC 60747-5-8:2019 provides a harmonized, internationally recognized basis for measuring LED optoelectronic efficiencies, supporting performance transparency and global trade in the semiconductor and optoelectronic industries.