LED灯具的性能评估白皮书（英文版）_6页_1mb

LED Luminaires Performance Evaluation Summary

Core Content

This white paper from Philips Lighting provides an in-depth evaluation of the performance of LED-based luminaires, focusing on both initial performance and over time performance. It outlines the standards used to measure and define these metrics, and highlights how Philips approaches the publication of performance data.

Main Viewpoints

Initial Performance Evaluation

Philips measures initial performance specifications for all LED-based luminaires in compliance with the relevant IEC standards. These specifications include:

• Initial rated input power (in W)
• Initial rated luminous flux (in lm)
• Initial LED luminaire efficacy (in lm/W)
• Luminous intensity distribution
• Initial Correlated Color Temperature (CCT) in K
• Initial rated Color Rendering Index (CRI)
• Initial rated chromaticity coordinates and expected tolerance (x, y) in SDCM

All initial specifications are measured at an ambient temperature of $25^{\circ}\mathrm{C}$.

Over Time Performance Evaluation

The performance of LED-based luminaires over time is evaluated using the IEC lifetime metric, which includes two key components:

1. Useful Life (LxBy): Describes the lumen maintenance of the luminaire over time. It is defined as the time during which y% of the population of luminaires fail to provide at least x% of the initial luminous flux. For example, $L_{80}B_{50}$ means that 50% of the population has failed to maintain at least 80% of the initial light output.
2. Time to Abrupt Failure (L0Cy): Describes the time at which y% of the population of luminaires no longer provide any light output due to failure of critical components. For example, $L_0C_{10}$ means that 10% of the population has failed abruptly.

Philips uses the LxBy metric to define the Rated Median Useful Life (e.g., $L_{80}B_{50}$), which is the value typically published on product datasheets, leaflets, or websites. The L0Cy metric is used to define the Time to Abrupt Failure, which is not currently published due to the lack of industry consensus on critical components to include in the calculation.

Key Information

IEC Performance Standards

Performance Over Time

• Useful Life is calculated based on lumen maintenance and is expressed as $\mathsf{L}{\mathsf{x}}\mathsf{B}{\mathsf{y}}$.
• Time to Abrupt Failure is based on the failure of critical components and is expressed as $\mathsf{L}0\mathsf{C}{\mathsf{y}}$.
• Philips uses a best-in-class tool to calculate these metrics using real-life endurance test data, accelerated testing, and design parameter analysis.

Published Performance Metrics

• Indoor LED Luminaires:

  • Median Useful Life values: $L_{90}B_{50}$, $L_{80}B_{50}$, $L_{70}B_{50}$
  • Driver failure rate at 5000 hours

• Outdoor LED Luminaires:

  • Useful Life value: $L_{80}B_{10}$
  • Driver failure rate at 5000 hours

All over-time performance claims are specified at an ambient temperature of $25^{\circ}\mathrm{C}$, with 12 burning hours per day and a number of switches aligned with the main application.

Additional Notes

• Over-time performance values are predictions, not direct measurements, due to the long lifespan of LED-based products.
• There is currently no standard for how to calculate these predictions, leading to variability in the quality of such data.
• Philips will publish the Abrupt Failure Value once there is industry consensus on which critical components to include in the calculations.