LED packages - Long-term luminous and radiant flux maintenance projection

IEC 63013:2017 is applicable to LED packages for general lighting services.
It specifies procedures and conditions for measuring the luminous flux maintenance of LED packages. It also provides the procedures and conditions (criteria) of projecting the long-term luminous flux maintenance based on limited luminous flux maintenance test data collected. Within the context of this document, wherever luminous flux measurement data is specified, radiant flux measurement data can also be used.

LED encapsulées - Projection à long terme concernant la conservation du flux lumineux et du flux énergétique

L'IEC 63013:2017 est applicable aux LED encapsulées d'utilisation courante.
Elle spécifie les procédures et les conditions pour mesurer la conservation du flux lumineux des LED encapsulées. Elle stipule également les procédures et les conditions (critères) de projection de la conservation du flux lumineux à long terme en se fondant sur des données d'essais collectées de la conservation du flux lumineux limitée. Dans le contexte du présent document, chaque fois que sont spécifiées des données de mesure du flux lumineux, des données de mesure du flux énergétique peuvent également être utilisées.

General Information

Status
Published
Publication Date
26-Jun-2017
Current Stage
PPUB - Publication issued
Start Date
27-Jun-2017
Completion Date
27-Jun-2017
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IEC 63013
Edition 1.0 2017-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
LED packages – Long-term luminous and radiant flux maintenance projection
LED encapsulées – Projection à long terme concernant la conservation du flux
lumineux et du flux énergétique
IEC 63013:2017-06(en-fr)
---------------------- Page: 1 ----------------------
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---------------------- Page: 2 ----------------------
IEC 63013
Edition 1.0 2017-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
LED packages – Long-term luminous and radiant flux maintenance projection
LED encapsulées – Projection à long terme concernant la conservation du flux
lumineux et du flux énergétique
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.140.99 ISBN 978-2-8322-4487-6

Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
---------------------- Page: 3 ----------------------
– 2 – IEC 63013:2017 © IEC 2017
CONTENTS

FOREWORD ........................................................................................................................... 3

INTRODUCTION ..................................................................................................................... 5

1 Scope .............................................................................................................................. 6

2 Normative references ...................................................................................................... 6

3 Terms and definitions ...................................................................................................... 6

4 Test method, data collection and sample size .................................................................. 7

5 Long-term luminous flux maintenance projection methods ............................................... 7

5.1 General ................................................................................................................... 7

5.2 Exponential fit function (EFF) .................................................................................. 7

5.2.1 Method ............................................................................................................ 7

5.2.2 Criteria ............................................................................................................ 7

5.3 Border function (BF) ............................................................................................... 8

5.3.1 Method ............................................................................................................ 8

5.3.2 Criteria ............................................................................................................ 8

5.3.3 Calculating the test data slope and the BF slope ............................................. 8

6 Temperature data interpolation ........................................................................................ 8

7 Adjustment of results ....................................................................................................... 8

8 Reporting......................................................................................................................... 9

Annex A (informative) Temperature acceleration – Arrhenius method (TA-A) ....................... 10

A.1 Method ................................................................................................................. 10

A.2 Criteria .................................................................................................................. 10

Annex B (informative) Process flow chart ............................................................................. 11

Annex C (normative) Border function (BF) ............................................................................ 12

Bibliography .......................................................................................................................... 14

Figure B.1 – Process flow chart ............................................................................................ 11

Figure C.1 – Three border functions ...................................................................................... 13

Table 1 – Information to be included in the report ................................................................... 9

Table C.1 – Calculated λ-value for three border functions ..................................................... 12

---------------------- Page: 4 ----------------------
IEC 63013:2017 © IEC 2017 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
LED PACKAGES – LONG-TERM LUMINOUS
AND RADIANT FLUX MAINTENANCE PROJECTION
FOREWORD

1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising

all national electrotechnical committees (IEC National Committees). The object of IEC is to promote

international co-operation on all questions concerning standardization in the electrical and electronic fields. To

this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,

Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC

Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested

in the subject dealt with may participate in this preparatory work. International, governmental and non-

governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely

with the International Organization for Standardization (ISO) in accordance with conditions determined by

agreement between the two organizations.

2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international

consensus of opinion on the relevant subjects since each technical committee has representation from all

interested IEC National Committees.

3) IEC Publications have the form of recommendations for international use and are accepted by IEC National

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5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity

assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any

services carried out by independent certification bodies.

6) All users should ensure that they have the latest edition of this publication.

7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and

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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is

indispensable for the correct application of this publication.

9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of

patent rights. IEC shall not be held responsible for identifying any or all such patent rights.

International Standard IEC 63013 has been prepared by subcommittee 34A: Lamps, of IEC

technical committee 34: Lamps and related equipment.
The text of this International Standard is based on the following documents:
FDIS Report on voting
34A/2008/FDIS 34A/2015/RVD

Full information on the voting for the approval of this International Standard can be found in

the report on voting indicated in the above table.

This document has been drafted in accordance with the ISO/IEC Directives, Part 2.

---------------------- Page: 5 ----------------------
– 4 – IEC 63013:2017 © IEC 2017

The committee has decided that the contents of this document will remain unchanged until the

stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to

the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
---------------------- Page: 6 ----------------------
IEC 63013:2017 © IEC 2017 – 5 –
INTRODUCTION

One of the benefits of LED lighting is their long lifetime compared to that of many other light

source technologies.

However, there is currently no international standard for predicting the long-term luminous flux

maintenance of LED packages. This document is intended to close this gap by specifying

methods for the long-term luminous flux maintenance projection.

This document is the result of the discussions led by a special expert group within IEC

technical committee 34 on this topic.

This expert group had collected a set of luminous flux maintenance measurements of 39 LED

package types, each tested at three different temperatures.
Various projection methods were analysed based on this set of test data.

Regarding the selection of models, there was a controversial discussion among the experts

and no unanimous agreement could be found.

It was concluded at the meeting in Berlin on 21 January 2014 to choose the TM-21 method as

the starting point of the analysis and to have the border function as an alternative in case the

TM-21 method was not applicable. It was further concluded that the Arrhenius temperature

acceleration should be included in an informative annex.

At the meeting on 26 January 2015 in Washington some further editorial improvements were

made and it was agreed to submit this document to IEC as a new project with a view to

developing a full international standard.

This new project was approved and all comments received during the enquiry stage were

discussed by the project team and resolved. This document incorporates the changes agreed

by the project team.
---------------------- Page: 7 ----------------------
– 6 – IEC 63013:2017 © IEC 2017
LED PACKAGES – LONG-TERM LUMINOUS
AND RADIANT FLUX MAINTENANCE PROJECTION
1 Scope
This document is applicable to LED packages for general lighting services.

It specifies procedures and conditions for measuring the luminous flux maintenance of LED

packages. It also provides the procedures and conditions (criteria) of projecting the long-term

luminous flux maintenance based on limited luminous flux maintenance test data collected.

Within the context of this document, wherever luminous flux measurement data is specified,

radiant flux measurement data can also be used.
These projection methods employ data collected as per ANSI/IES LM-80-15 (LM-80).

The long-term projection is based on the exponential-fit-function procedure of IES TM-21-11

(TM-21), and gives an alternative border function procedure in the case where the

exponential-fit-function of IES TM-21-11 is not applicable.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their

content constitutes requirements of this document. For dated references, only the edition

cited applies. For undated references, the latest edition of the referenced document (including

any amendments) applies.

IEC 62504, General lighting – Light emitting diode (LED) products and related equipment –

Terms and definitions
IES TM-21-11, Projecting Long Term Lumen Maintenance of LED Light Sources
IES LM-80-08 , IES Approved Method for Measuring Lumen Maintenance of LED Light
Sources

ANSI/IES LM-80-15, IES Approved Method: Measuring Luminous Flux and Color Maintenance

of LED Packages, Arrays and Modules
3 Terms and definitions

For the purposes of this document, the terms and definitions given in IEC 62504 and the

following apply.

ISO and IEC maintain terminological databases for use in standardization at the following

addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
__________

Withdrawn. This edition was replaced in 2015 by IES LM-80-15, IES Approved Method: Measuring Luminous

Flux and Color Maintenance of LED Packages, Arrays and Modules.
---------------------- Page: 8 ----------------------
IEC 63013:2017 © IEC 2017 – 7 –
3.1
case temperature

temperature value of the thermocouple attachment point as specified by the manufacturer

4 Test method, data collection and sample size

Luminous flux maintenance test data shall be collected according to the methods described in

ANSI/IES LM-80-15. Test data collected according to IES LM-80-08 shall be acceptable.

When collecting data for long-term luminous flux maintenance projection, it is recommended

to use intervals smaller than 1 000 h for the measurement of the luminous flux and to perform

measurements beyond 6 000 h.
Recommendations on sample size are found in IES TM-21-11.
5 Long-term luminous flux maintenance projection methods
5.1 General
The following projection methods are included in this document:
• Exponential fit function (EFF)
• Border function (BF)

The EFF method shall be used as the primary method, with the BF method used as an

alternative only when the EFF calculation yields a negative or zero α−value, see Annex B

(Flowchart).

If at least one temperature data set leads to the application of the BF method (α ≤ 0), then all

temperature data sets of the same LED package shall be evaluated with the BF method.

Annex A describes a temperature acceleration method according to the temperature
acceleration Arrhenius (TA-A) formula.
5.2 Exponential fit function (EFF)
5.2.1 Method

The exponential fit function method (EFF), as described in IES TM-21-11, is based on the

assumption that after early luminous flux degradation modes are complete, the subsequent

test data can be fitted and extrapolated using an exponential curve-fit function, using the

formula
f (t) = B exp(−αt) (1)

The luminous flux maintenance projection shall be performed according to IES TM-21-11,

Section 5.
5.2.2 Criteria

The EFF method shall be applied only to data sets showing normal degradation with α > 0, a

“downward” projection. In cases where the data fit yields an EFF with α ≤ 0, a “flat or upward”

projection, then the BF method shall be applied.
---------------------- Page: 9 ----------------------
– 8 – IEC 63013:2017 © IEC 2017
5.3 Border function (BF)
5.3.1 Method

The border function (BF) method is based on the assumption that an exponential model is a

conservative estimation of the actual long-term luminous flux maintenance, and is applied

when the criteria of 5.2.2 have met.
The border function shall be calculated according to Annex C.

Each border function has an associated life and luminous flux maintenance target value.

The associated life target is considered to be a median life and shall be a multiple of 5 000 h

and the luminous flux maintenance target shall be 70 %, 80 % or 90 %.
5.3.2 Criteria

• the tested luminous flux value is greater than the value calculated as per the border

function for at least the last 2 000 h of the test, and is supported by at least 3 successive

measurements points, and

• the value of the slope of the test data for the last 2 000 h of the test is greater than the

corresponding value of the slope of the border function for the same time period (for the

calculation of the slopes see 5.3.3),

then the associated median life and luminous flux maintenance target value of the BF may be

used as the projected median life L for the tested LED package.
5.3.3 Calculating the test data slope and the BF slope

Calculate the slope of the test data for the last 2 000 h by making a linear fit to all averaged

test points in that time period. At least 3 successive measurement points shall be applied. The

regression coefficient of the linear fit shall be reported.

The corresponding slope of the BF for the last 2 000 h is approximated by the formula

BFslope = -λ exp(-λ (t -1 000 h)) (2)
end
where t is the time of the last test point.
end
6 Temperature data interpolation

If temperature interpolation is employed, then it shall be performed according to the Arrhenius

formula in IES TM-21-11, Clause 6.
NOTE Additional information on the Arrhenius method can be found in IEC 62506.
Temperature interpolation is limited to the temperature range between the tested
temperatures.
7 Adjustment of results
The results of 5.2 and 5.3 shall be adjusted according to IES TM-21-11, 5.2.5.
---------------------- Page: 10 ----------------------
IEC 63013:2017 © IEC 2017 – 9 –
8 Reporting

The report of the luminous flux maintenance projection shall include the following information

shown in Table 1. Only L and L values adjusted as per Clause 7 shall be reported,

70 xx
according to the notation in IES TM-21-11, 5.2.6.
Table 1 – Information to be included in the report
Description of LED package tested (manufacturer, model, catalogue number)
Sample size
Number of failures during testing period
Forward current(s) used in the test mA
Maintenance test duration h
Case temperature(s) during testing
Projection method used
(including values of mathematical fit parameters)
Test duration used for projection as per IES TM-21-11 h to h
Reported L (Dk) (e.g. 85 °C, tested) h
Reported L (Dk) (e.g. 95 °C, interpolated) h
Reported L (Dk) (e.g. 105 °C, tested) h
---------------------- Page: 11 ----------------------
– 10 – IEC 63013:2017 © IEC 2017
Annex A
(informative)
Temperature acceleration – Arrhenius method (TA-A)
A.1 Method

The Arrhenius method is based on the basic assumption that the ageing (degradation)

mechanism can be accelerated by raising the case temperature and that the activation energy

E can be used to describe this acceleration behaviour. The basic equations describing this

model are that the luminous flux degrades according to a function f(t,ρ) with degradation

parameter ρ depending on temperature T as follows
(A.1)
ρ(T ) = K exp(−E /k T )
a B

The activation energy E and two measured points at time and temperature conditions (τ ,T )

a 1 1

and (τ ,T ) where light degradation to a luminous flux maintenance factor is observed can be

2 2
used to describe an acceleration factor according to the formula
τ E  1 1 
 
1 a
 
AF = = exp × − (A.2)
 
 
τ k T T
2 B  1 2 
where
AF is the acceleration factor due to temperature differences;
E is the activation energy in eV;
k is the Boltzmann constant in eV/K;
τ , τ are the times with τ > τ in h;
1 2 1 2
T , T are the temperatures with T < T in K.
1 2 1 2

The Arrhenius luminous flux maintenance projection should be performed according to

IEC 62506:2013, 5.6.1.2.
A.2 Criteria
The following criteria are applicable:

– The activation energy E should be known for application of the Arrhenius model. The LED

package manufacturer estimates the activation energies for the relevant degradation

modes each time they qualify a new component technology. The activation energy should

be in the range 0,1 eV < E < 1,0 eV.

– There should be no evidence for positive degradation, i.e. no “upward” projection in the

data set.

– For each temperature in the data set, higher temperatures should show more rapid

degradation.

– The TA-A method should not be used if evidence exists that the temperature acceleration

has caused a change in degradation mode.

– If there is evidence for more than one significant degradation mode, then the TA-A method

should be applied to each degradation mode separately. For example, if the data set

shows a significant change in degradation rate, i.e. mode 1 completed and mode 2

continued onward, then the acceleration factor determined for mode 1 should only be

applied to mode 1 and not to mode 2 or any future degradation modes.
---------------------- Page: 12 ----------------------
IEC 63013:2017 © IEC 2017 – 11 –
Annex B
(informative)
Process flow chart
Figure B.1 outlines the process described in this document.
LM-80 test data
Clause 4
EFF (IES TM-21-11)
Subclause 5.2.1
Criteria
α ≤ 0 Border function
Subclause
Subclause 5.3
5.2.2
α > 0
Temperature
Interpolation
Clause 6
Adjustment
Clause 7
Reporting
Clause 8
IEC
Figure B.1 – Process flow chart
---------------------- Page: 13 ----------------------
– 12 – IEC 63013:2017 © IEC 2017
Annex C
(normative)
Border function (BF)
A border function B(t) shall be defined using the formula
B(t) = exp(-λt) (C.1)
where
λ is the exponential coefficient;
t is the time in hours.

Setting t = L and B(L ) = x/100 and solving this equation for λ gives the parameter for use in

x x
the border function equation.
Example:

Using 70 % as a target for the luminous flux maintenance projection, the following values for

the exponential coefficient λ are calculated, see Table C.1.
Table C.1 – Calculated λ-value for three border functions
Luminous flux maintenance L [h] 25 000 35 000 50 000
-5 -5 -6
Corresponding value of λ [1/h] 1,43 ×10 1,02×10 7,13×10

Other values for λ can be calculated for other target L values and for other L targets.

70 x
Figure C.1 shows the three border functions given in Table C.1.
---------------------- Page: 14 ----------------------
IEC 63013:2017 © IEC 2017 – 13 –
L 25 000 h
0,9 L 35 000 h
L 50 000 h
0,8
0,7
0,6
0,5
0 5 000 10 000 15 000 20 000 25 000 30 000 35 000 40 000 45 000 50 000 55 000
Time (h)
IEC
Figure C.1 – Three border functions
Lumen maintenance
---------------------- Page: 15 ----------------------
– 14 – IEC 63013:2017 © IEC 2017
Bibliography
IEC 62506:2013, Methods for product accelerated testing
___________
---------------------- Page: 16 ----------------------
– 16 – IEC 63013:2017 © IEC 2017
SOMMAIRE

AVANT-PROPOS .................................................................................................................. 17

INTRODUCTION ................................................................................................................... 19

1 Domaine d'application ................................................................................................... 20

2 Références normatives .................................................................................................. 20

3 Termes et définitions ..................................................................................................... 20

4 Méthode d'essai, recueils des données et effectif d'échantillon ...................................... 21

5 Méthodes de projection concernant la conservation du flux lumineux à long terme ........ 21

5.1 Généralités ........................................................................................................... 21

5.2 Fonction d'approximation exponentielle (EFF) ....................................................... 21

5.2.1 Méthode ........................................................................................................ 21

5.2.2 Critères ......................................................................................................... 22

5.3 Fonction enveloppe (BF) ....................................................................................... 22

5.3.1 Méthode ........................................................................................................ 22

5.3.2 Critères ............................................................................

...

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