United States: Want to develop short-term prediction LED system life test program

Technology Dynamics Because LEDs emit light directly from a solid, they are simple and rugged, have no consumable parts, and have low heat loss and long life. Theoretically, the life of a single chip can reach 100,000 hours, but the actual application of LED lamps and lanterns is often a series and parallel combination of dozens of chips, and also with a power supply, so the combined LED lamp life of about 50,000 hours. Even so, it is much longer than the life of incandescent lamps (about 1,000 hours) and energy-saving lamps (about 10,000 hours).

In many applications, most LED lighting systems last longer than traditional light sources. However, some users of solid-state lighting (SSL) may find that the failure rate of the selected LED product is much faster than that stated in the data sheet. Shortening the life cycle will hurt the user's confidence. LED system failures can be fatal (the product can not emit light) or the data is different (having light, but much less than the design value).

The LED system has many components (as shown in Figure 1) and any component failure can cause the system to fail. However, the current industry will practice testing LED devices and consider 70% of the lumen depreciation time (such as parameter failure) as the lifetime of the LED system. Since industry standards only require the testing of one component in the system and the lifetime of the LED system is evaluated by considering only one type of failure, the manufacturer's reported product life may be in some applications more than the actual product time used by the consumer. It's much longer. The Rensselaer Lighting Research Center (LRC) conducted a study to illustrate the problem and propose potential changes in practice.

Figure 1: Composition of LED system components

Since 2009, the Lighting Research Center (LRC) at Rensselaer Polytechnic Institute has been studying the lifetime of LED systems to develop a test program for short-term life prediction. Early studies funded by the Solid State Lighting System and Technology Alliance (ASSIST) found that the cause of the failure was due to Delta temperature or temperature changes in the on/off cycle and the residence time or duration of the system operating at the highest steady state temperature (see figure 2). In 2014, the Bonneville Power Bureau and the New York State Energy Research and Development Agency (NYSERDA) jointly funded the expansion of earlier research. In this study, three types of LED systems purchased from the market were tested, including LEDA lamps, LED MR16 lamps, and LED downlights. A total of 277 LED products were tested.

Figure 2: LED temperature-period curve

Solid State Lighting SSL Test Development

Overall, the research results show that in order to more accurately estimate the lifetime of the LED system, the new test practice must include system-wide testing and on/off switching. When reporting system life, the shorter of the two failure modes (fatal or parametric) should be regarded as the life of the product, because in the application, the LED system may encounter two types of failures and Conditions, one type can dominate.

Research results show that if the operating temperature and the typical on/off mode are known, a test program can be developed to accurately predict the lifetime of the LED system in any application. By testing the entire LED system, including a power cycle with enough dwell time, and by considering lethality and parametric failure, the LED system lifetime can be accurately predicted over a 3000-hour test period.

At present, the incorrect specification of product specifications is caused by the industry's testing requirements for LED product life cycle data. Therefore, there is an urgent need to modify industry testing standards to better guide product manufacturers and consumers.

The original title of the LED industry test standard is not enough life is difficult to accurately estimate!

Specifications

Recessed LED Downlight with built-in Microwave Motion Sensor

Model	AM-6.0GY
Luminous flux	800~900lm
Luminous Efficacy	>80lm/W
Colour Rendering index	80
Beam Angle	140°
Light Decay	<30% over 10,000 hours
Rated Lifespan	>30,000 hours
Power consumption	10 watts
Input voltage / Frequency	80-260vac 50-60HZ
Reflector / Diffuser	Frosted diffuser
Operating Environment	-20°c~+50°c
Dimensions	Φ193*77mm
Hole Cut Size	Φ160~Φ180mm
LED Source	56pcs SMD2835
Working mode	ON/OFF or Full/Dim
Sensor Range	180*360 degree
Sensor Distance	6-8m Radius
Delay Time	18-25s

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