MANUTENÇÃO DAS CARACTERÍSTICAS NOMINAIS
DE LUMINÁRIAS A LED:
INDUTORES OU INIBIDORES DA CONFIABILIDADE
(Maintenance of Led Luminaire Nominal Characteristics: Reliability Inductors and Inhibitors)
Oswaldo Sanchez Junior
IPT – CTMNE – LEO e
USP – IEE – PPGE
São Paulo - Brasil
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IPT (2013)
Infraestrutura:
Sede: Cidade Universitária - São Paulo - SP
Unidades: Franca e São José dos Campos - SP
Unidades Técnicas:
Centros e Núcleos: 11
Laboratórios e Seções Técnicas: 37
Colaboradores:
428 Pesquisadores
295 Técnicos
267 Apoio Administrativo
105 Estagiários
Orçamento: R$153 M
68% P&D&I e serviços
32% GESP
Produção Científica:
Documentos técnicos emitidos: 26.951
Publicações: 338
Patentes: 11
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Source: Moon-Hwan Chang et al., Light emitting diodes reliability review,
Microelectronics Reliability 52 (2012) 762–782.
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THE ENGINE OF LED TECHNOLOGY IN LIGHTING
Source: Azevedo, I.L., M.G. Morgan and F. Morgan. 2009. The transition
to solid-state lighting. Proceedings of the IEEE 97:481-510.
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TYPES OF FAILURES ENCOUNTERED
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A TYPICAL GAP ASSESSMENT
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LED STRUCTURE
Source: Moon-Hwan Chang et al., Light emitting diodes reliability review,
Microelectronics Reliability 52 (2012) 762–782.
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AREAS IN NEED OF IMPROVEMENT AND STUDY REGARDING LEDS:
•the internal quantum efficiency of the active region
•light-extraction technology
•current-flow design
•the minimization of resistive losses
•electrostatic discharge stability
•increased luminous flux per LED package
•purchase cost
THERMAL STANDARDS DEPENDENCE:
(functions of the junction temperature)
•light output
•Color
•life-time.
Source: Moon-Hwan Chang et al., Light emitting diodes reliability review,
Microelectronics Reliability 52 (2012) 762–782.
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LED LIFETIMES CAN VARY FROM 3 MONTHS
TO AS HIGH AS 50,000–70,000 H
Source: Moon-Hwan Chang et al., Light emitting diodes reliability review,
Microelectronics Reliability 52 (2012) 762–782.
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ONE METHOD FOR PREDICTING THE LIFETIME OF LEDS
(1) measuring the light output of samples at each test readout time;
(2) estimating LED life under the accelerated test conditions (using
functional curve fitting of time-dependent degradation under the test
conditions) or finding observed lifetime for L50 or L70;
(3) calculating an acceleration factor; and
(4) predicting lifetime under the usage conditions by using the
acceleration factor multiplied by the lifetime of the test condition, as
shown in Eq. (1):
Where:
Ea is the activation energy [eV],
Tu is the junction temperature at usage conditions,
Ta is the junction temperature at accelerated conditions, and
k is the Boltzmann constant (8.6 EE-5 eV/K)
Source: Moon-Hwan Chang et al., Light emitting diodes reliability review,
Microelectronics Reliability 52 (2012) 762–782.
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Source: Moon-Hwan Chang et al., Light emitting diodes reliability review,
Microelectronics Reliability 52 (2012) 762–782.
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Source: Moon-Hwan Chang et al., Light emitting diodes reliability review,
Microelectronics Reliability 52 (2012) 762–782.
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ANALYSING THE BEHAVIOUR OF LED MODULE DRIVER
UNDER VARIATION OF AMBIENT TEMPERATURE
Fluorescence vs. Phosphorescence:
Source: Moon-Hwan Chang et al., Light emitting diodes reliability review,
Microelectronics Reliability 52 (2012) 762–782.
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COLOR PERCEPTION WITH TWO DIFFERENT LEDS MODELS
Source: U.S. Department of Energy 2012 Building
Technologies Program Solid-State Lightning Fact Sheet
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Overview of the test luminaire:
Experimental set-up to obtain LED
emission spectrum. The luminaire
inside the oven is on a settled
temperature and aiming its light to
PTFE target we can obtain the
spectrum with the radiometer.
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Temperature at different spots of the luminaire versus the
ambient temperature inside the oven:
M + C: LED module and controller inside the greenhouse.
M - C: LED module inside the greenhouse and outside controller.
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Effect of the variation of the temperature over the CRI:
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Effect of the variation of the ambient temperature over the
chromatic coordinate X and Y:
y
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Effect of the variation of ambient temperature over the
correlated color temperature:
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Spectrum emitted by the lamp for the MC procedure during extreme
ambient temperature: 34.5 º C and 85.7 º C
espectro
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Effect of the increased temperature on total harmonic distortion:
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Effect of the ambient temperature on electric current:
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CONCLUSIONS
-We can note a sharply influence of the variation of the
temperature in distinct components that makes up a
luminaire project.
-These components most of the time are sold as separated
items and most of the time when these items are put
together sometimes the compability between these items
and the final product is not took into account.
RECOMMENDATIONS
-This experiment may be improved to analyze others
colorimetric and electrical parameters that are part of the
project of the luminaire.
-Also analyze different types of luminaires, such as those
used for public lightning.
-The new parameters to study could be life cycle and the
luminaire´s degradation suiting the boundary conditions to a
Brazilian reality.
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Obrigado pela oportunidade!
Contatos:
Oswaldo Sanchez Junior
Fone (55 +11) 3767-4588
E-mail: [email protected]
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