2 9 Chromaticity co rdinates, cor elated colour temp rature CCT an colour ren erin.. 2 9.2 Cor elated colour temp rature CCT... 4 An ex H inf ormative Test eq ipment for temp rature me s
Mandatory marking 1 4
Information on the parameters shown in Table 1 shall be provided by the manufacturer or responsible vendor and be located as described
The information shall be related to the maximum performance operating temperature t p rated , except for the t p -point (item j), the dimensions (item n) and the availability of a heat sink (item o)
This information is in addition to the mandatory marking required by IEC 62031
For scaleable modules, refer to 6.1 and mark the reference dimensions in the leaflet
Table 1 – Mandatory marking and location of marking 1
When evaluating LED modules, key parameters to consider include the rated luminous flux (lm), photometric code, and rated median useful life along with the lumen maintenance factor It's essential to note the rated abrupt failure value and the lumen maintenance code, as well as the categories of rated chromaticity coordinate values for both initial and maintained states Additionally, the correlated colour temperature (K), rated colour rendering index, and the thermal performance rating (°C) are crucial Other important factors include the ageing time, ambient temperature range, rated efficacy (lm/W), and the dimensions with tolerances Lastly, the availability of a heat sink, displacement factor, and temperature ramping should also be assessed.
1 Regional requirements may apply and overrule
2 If the space on the LED module is not large enough, marking on the packaging only is sufficient
If the t p-point and t c-point coincide, the t p-point will not be individually marked on the LED module; instead, it will be included in the product datasheet The t p-point marking may optionally appear on the product itself, as well as in product datasheets, leaflets, or on websites.
5 Marking according to a) and b) of Table 1 is not required on the packaging where the product is not delivered in an end-consumer packaging
Additional marking 1 5
Manufacturers or responsible vendors may provide the relationships between at least three temperatures at the t p-point, including the recommended t p rating as outlined in Table 1, for built-in and integral LED modules, regardless of whether they include heat management An example of this can be found in Table 2.
Independent LED modules typically come with manufacturer-provided data that outlines the relationship between at least three ambient temperatures, including 25 °C, and their estimated lifetimes For reference, see Table 2.
Table 2 – LED module life time information t p temperature (°C) measured at the t p -point XX a XX a XX a
Rated life time (h) XX XXX a XX XXX a XX XXX a a Values to be declared by the LED module manufacturer
Additional information from the LED module manufacturer to the tabled t p temperatures and life time is allowed For the chosen life time, t p is a fixed value
NOTE Verification is currently not covered by this standard
In addition to 4.1 , the marking as given in Table 3 may be used
Table 3 – Optional marking and location of marking
Parameters LED module Packaging LED module datasheets, leaflets or website a) luminous intensity distribution – – x b) beam angle – – x c) peak intensity – – x
All measured dimensions of a LED module in a sample shall be within the tolerances as declared by the manufacturer or responsible vendor
Compliance is checked with suitable means of measurement
General test conditions 1 6
The LED modules for which compliance with this standard is claimed shall comply with the requirements of the safety standard IEC 62031
For compliance with EMC requirements except harmonics, reference is made to regional requirements For relevant standards see Bibliography
It should be regarded that only those types of LED modules are subject to EMC requirements which
• in case of harmonic current are directly connected to the mains and have active elements on board;
• in case of radiated or conducted disturbances are directly connected to the mains (Type 1 ) or to a battery;
• in case of immunity are directly connected to the mains (Type 1 ) or to a battery
Testing duration is 25 % of rated life time up to a maximum of 6 000 h
Alternatively, test data from IES LM-80 shall be used for the derivation of maintained values at 25 % of rated life, maximum 6 000 h, together with related compliance criteria, as specified in Annex I
Additional LED modules within the same family may experience reduced testing durations For family identification details, refer to Table 4, while Table 7 provides information on sample sizes for family testing.
Test conditions for testing electrical and photometric characteristics, lumen maintenance and life are given in Annex A
All tests are performed on a minimum of n identical LED modules, as specified in Table 7 The LED modules utilized in endurance testing must not be employed in any other tests.
For Type 2 and Type 3 LED modules, testing necessitates the use of a separate reference power supply and control gear, as specified by the LED module manufacturer or responsible vendor.
LED modules with dimming control shall be adjusted to maximum light output for all tests
LED modules with adjustable colour point shall be adjusted/set to one fixed value as indicated by the manufacturer or responsible vendor
LED modules, particularly those with scalable linear geometries, should be tested at a length of 50 cm If scalability is not applicable, testing should occur at the nearest available length.
50 cm The LED module manufacturer shall indicate which controlgear is suitable for this length.
Creation of module families to reduce test effort 1 7
This article introduces a framework for LED module manufacturers to enhance platform designs by utilizing data from an existing baseline product, which has been tested for operational time as outlined in section 6.1 The baseline product is recognized as the inaugural LED module that meets this standard and is designated as part of the family.
When selecting LED modules, it is crucial to consider each family individually, ensuring that all modules are produced by the same manufacturer and adhere to a consistent quality assurance system Variations within the range, such as Correlated Color Temperature (CCT), must maintain uniformity in materials, components, and construction methods Additionally, type test samples should be chosen in collaboration with both the manufacturer and the testing facility.
Requirements for the identification of a family of LED modules for type testing are given in definition 3.21 and used in Table 4
Testing time can be shortened to 1,000 hours for family 3 if the part characteristics meet the specified conditions in Table 4 This applies when critical components remain unchanged or when the same technology is utilized with updated materials.
Table 4 – Allowed variations within a family
Part characteristics intended to be varied Conditions for acceptance
The temperature measurement point value of the LED package, as provided by the LED module supplier, along with other components, should remain the same or lower This is applicable if the rated lifetime is equal to or greater than that of the baseline product, as specified by the manufacturer or responsible vendor.
Optics (see NOTE 2) The test results showing the effect of optical material change shall be documented in the manufacturer’s technical file
The LED package temperature (t p) should remain constant or decrease if its rated lifetime is equal to or exceeds that of the baseline product, as specified by the manufacturer or responsible vendor.
Type 2 LED modules maintain a consistent or reduced temperature (t p) when their rated lifetime matches or exceeds that of the baseline product, as specified by the manufacturer or responsible vendor.
A statistical failure shall show equal or lower failures
NOTE 1 The value of t p can be used as long as the correlation between the temperature measurement value of LED and t p is defined (process under consideration)
Optics encompasses various components such as secondary optics (lenses), reflectors, trims, and gaskets, along with their interconnections The outcomes of these elements can affect luminous flux, peak intensity, intensity distribution, beam angle, and shifts in color coordinates, correlated color temperature (CCT), and color rendering index (CRI).
Any change on part tolerances are documented in the manufacturer’s technical file
Compliance testing of family members
The performance characteristics of family members before and after reduced testing time must align with the values specified by the LED module's manufacturer or vendor.
– results of acceleration operated life test
Documentation of data shall be provided to the testing station in the manufacturer’s technical file
All tested LED modules must maintain their measured values within the limits specified by the manufacturer or vendor The values recorded should match or exceed the provided specifications It is essential that every LED module in the sample successfully passes the testing criteria.
LED module power 1 9
For measurement conditions, see Annex A
The initial power consumed by each individual LED module in the measured sample shall not exceed the rated power by more than 10 %
The penultimate paragraph of 1 1 should be regarded.
Displacement factor (u.c.) 1 9
The displacement factor of integrated LED modules (Type 1 ) shall be measured according to Annex E LED modules with dimming control shall be adjusted to maximum light output
Displacement factor measurement of semi- and non-integrated LED modules (Type 2 and Type 3) is not applicable
NOTE 1 See Annex F for explanation and relation of displacement factor, distortion factor and power factor
NOTE 2 The distortion factor is covered by IEC 61 000-3-2: 2005/AMD 2: 2009 which deals with the limitations of harmonic currents injected into the public supply system
The measured displacement factor for each individual module of the sample shall not be less than the marked value by more than 0, 05
Luminous flux 1 9
Luminous flux is measured according to Annex A
The initial luminous flux of each individual LED module in the measured sample shall not be less than the rated luminous flux by more than 10 %.
Luminous intensity distribution, peak intensity and beam angle 1 9
The requirements of 8.2.4 and 8.2.5 shall be applied to LED modules having a directional (spot) distribution
NOTE Luminous intensity distribution of a LED module can be specific for an application
The light intensity emitted from the LED module in various directions is assessed using a goniophotometer All photometric data will be reported for the LED module functioning at its rated temperature, as specified in Clause A.1.
The allowed photometric variations detailed should take account of manufacturing tolerances
The distribution of luminous intensity shall be in accordance with that declared by the manufacturer The measurement is conducted according to A.3.3
The initial peak intensity of each LED module in the measured sample must meet or exceed the peak intensity value specified by the manufacturer or responsible vendor.
Compliance is checked according to Annex A
When a manufacturer or vendor specifies a beam angle value, each LED module in the sample must not differ by more than 25% from the rated value.
Compliance is checked according to Annex A.
Luminous efficacy
The efficacy of an LED module is determined by dividing its measured initial luminous flux by its initial input power For details on measuring luminous flux, refer to section A.3.2.
All tested LED modules must demonstrate an efficacy of at least 80% of the rated efficacy specified by the manufacturer or responsible vendor.
9 Chromaticity coordinates, correlated colour temperature (CCT) and colour rendering
Chromaticity coordinates
Initial chromaticity coordinates are recorded, followed by a second measurement of maintained chromaticity coordinates at the specified operational time Both sets of measured chromaticity coordinate values must fall within one of four categories, as outlined in Table 5 These categories correspond to specific MacAdams ellipses surrounding the rated chromaticity coordinate value, with the size of the ellipse, expressed in n-steps, indicating the tolerance or deviation in the chromaticity coordinates of each LED module.
For compliance of family members, refer to 6.2 3
All tested LED modules must have their measured chromaticity coordinate values, both initial and maintained, fall within specified categories These values should not exceed the established chromaticity coordinate tolerance limits.
4 Average value and confidence level are under consideration
5 Average value and confidence level are under consideration
The IEC 6271 7:201 4+AMD1 :201 5 standard specifies that the measured values of LED modules must align with the category indicated by the manufacturer or responsible vendor, as detailed in Table 1 Additionally, these measured values should meet or exceed the rated values For chromaticity coordinate measurements, sample LED modules must be chosen from four distinct batches.
Table 5 – Tolerance (categories) on rated chromaticity coordinate values
Size of MacAdam ellipse, centred on the rated colour target
The behavior of a LED module's chromaticity coordinates is defined by presenting the initial and maintained chromaticity coordinate measurements For further details, refer to Annex D.
This standard pertains to LED modules, allowing users to select a Correlated Color Temperature (CCT) value that best meets the specific needs of their application The establishment of standardized color target points is currently being evaluated.
The tolerance areas for color perception are derived from the ellipses established by MacAdam, as detailed in the 1943 publication of the Journal of the Optical Society of America, and are typically utilized for fluorescent and other discharge lamps.
NOTE 2 See Annex A for measurement method of chromaticity coordinate values for LED modules.
Correlated colour temperature (CCT)
To ensure interchangeability, preferred values are being evaluated The four-digit CCT value is divided by 100, and the resulting figure is rounded up to the nearest integer when applying the photometric code outlined in Annex D.
For compliance of family members, refer to 6 2 3
For all of the tested LED modules in a sample, the measured correlated colour temperature shall not move beyond the values as declared by the manufacturer or responsible vendor
NOTE In Japan, the requirements on colour classification and indication are specified in JIS Z 91 1 2.
Colour rendering index (CRI)
The initial colour rendering index (CRI) of a LED module is measured A second measurement is made at an operational time as stated in 6.1
For all tested LED modules in a sample the measured CRI values shall not have decreased by more than:
– 3 points from the rated CRI value (see Table 1) for initial CRI values, and
6 The colour variation between the LED modules in a sample from different production runs resembles the variation within longer periods of production
– 5 points from the rated CRI value (see Table 1) for maintained CRI values
The lifespan of an individual LED module, as detailed in Annex C, is influenced by two main factors: gradual light output degradation due to material deterioration and sudden light output degradation resulting from electrical component failure Both types of degradation are assessed through endurance tests, which serve as indicators of reliability and overall lifespan.
The definitions outlined in sections 3.2 and 3.7 highlight the Median Useful Life and the indicated fraction (B 50) of tested LED modules, which may not meet the testing requirements specified in sections 1.0.2 and 1.0.3.
The rated lumen maintenance factor may vary depending on the application of the LED module Dedicated information on the chosen percentage should be provided by the manufacturer
Due to the extended lifespan of LED modules, measuring actual lumen reduction over time (e.g., L70) is considered impractical and time-consuming Therefore, this standard utilizes test results to establish the expected lumen maintenance code for any LED module.
The lumen maintenance of LED modules varies significantly by type and manufacturer, making it challenging to represent all LEDs' lumen maintenance with straightforward mathematical formulas A rapid initial drop in lumen output does not necessarily indicate that an LED will fail to reach its rated lifespan.
NOTE 3 Other methods providing more advanced insight in lumen depreciation over LED module life are under consideration
The standard introduces "lumen maintenance codes" that address the initial reduction in lumen output until a specified operational time, as outlined in section 6.1 Three distinct codes are provided to define lumen maintenance as a percentage of the initial luminous flux.
Table 6 – Lumen maintenance code at an operational time as stated in 6.1
The initial luminous flux must be measured and subsequently repeated at the operational time specified in section 6.1 This initial value is normalized to 100% and serves as the baseline for assessing the lifespan of the LED module The luminous flux measured at the operational time indicated in section 6.1 will be expressed as a maintained value, representing a percentage of the initial luminous flux.
It is recommended to measure the lumen output values at 1 000 h intervals (expressed as a percentage of the initial value) for a total equal to an operational time as stated in 6.1
Assigning a code to LED modules provides additional insight into the reliability of their measured values; however, it does not predict their achievable lifetime Modules with a higher code may perform better or worse than those with a lower code.
For marking of the lumen maintenance factor (x) and the lumen maintenance codes, see Table 1
Compliance at 25 % of rated life with a maximum of 6 000 h test duration:
For compliance of family members, refer to 6 2 3
An individual LED module is considered having passed the test when the following criteria have been met
1) The measured luminous flux value at 25 % of rated life (with a maximum duration of
6 000 h) shall not be less than the luminous flux, multiplied by the rated lumen maintenance factor (x)
The lumen maintenance ratio, which compares the initial luminous flux to the maintained luminous flux, must align with the "lumen maintenance code" specified by the manufacturer or responsible vendor.
A sample of n LED modules, as outlined in Table 7, undergoes a rated lifetime test at 25% capacity for a maximum duration of 6,000 hours The test is considered successful if at least 90% of the LED modules meet the passing criteria by the end of the testing period.
(2) Measured luminous flux value at an operational time as stated in 6.1
(3) Lower limit line: claimed flux decrease over rated life L 70
Figure 2 – Luminous flux depreciation over test time
LED modules shall be subjected to the following tests specified in 1 0.3.2 to 1 0.3.4
NOTE All tests can be carried out in parallel with different LED modules
Luminous flux as % of initial luminous flux
The temperature cycling test will be performed according to IEC 60068-2-1, Test Nb: Change of temperature with a specified rate of change, under the specified conditions Either of the alternative tests 1 0.3.2.2 or 1 0.3.2.3 may be selected for this procedure.
The LED module must be mounted on a suitable heat sink and tested in accordance with IEC 60068-3-5, ensuring it operates at the specified nominal current and test voltage The heat sink should allow the LED module to reach its maximum rated t p temperature (± 10 K) after thermal stabilization, within a test chamber set to 40 °C ± 10 °C The maximum ambient temperature for the temperature cycle is the test chamber temperature at which t p is achieved, while the minimum ambient temperature is determined by subtracting 50 K from this value These temperatures define the parameters for the temperature cycle.
When the manufacturer declares in his literature a temperature range with minimum and maximum temperatures, these values shall be used
The test shall consist of 250 cycles
The LED module, after reaching its maximum ambient temperature, must be turned off Subsequently, the ambient temperature within the test chamber should be reduced at a rate of 10 K/min until it reaches the minimum test temperature.
2) The switched off LED module shall be held at the minimum ambient temperature level for
50 min After this period the LED module shall be switched on and off at the low ambient temperature 1 0 times with the cycle 1 0 s on / 50 s off
4) Increase the temperature in the test chamber at a rate of 1 0 K/min to the maximum ambient test chamber temperature.
5) The switched on LED module shall be held at the maximum ambient temperature level for
50 min After this period the LED module shall be switched on and off at the high ambient temperature 1 0 times with the cycle 1 0 s on / 50 s off
At the conclusion of the test, all LED modules must function properly, maintaining a luminous flux that adheres to the specified lumen maintenance code for a minimum duration of 15 minutes, without exhibiting any physical damage from temperature cycling, such as cracks or label delamination.
The temperature requirements of A.1 do not apply
The LED module is placed in a test chamber in which the temperature is varied from ‒1 0 °C to +50 °C 7 over a 4 h period and for a test duration of 250 8 periods (1 000 h)
The LED module is mounted on an appropriate heat sink to reach its maximum rated t p temperature at +50°C test chamber temperature
A 4-hour testing period includes 1 hour at each extreme temperature, with a 1-hour transfer time between these extremes at a rate of 1 K/min During this process, the LED module operates for 17 minutes, and compliance is verified accordingly.
At the conclusion of the test, all LED modules must function properly, maintaining luminous flux within the specified lumen maintenance code for a minimum duration of 15 minutes, while also exhibiting no physical damage from temperature cycling, such as cracks or label delamination.
NOTE 1 The switching period of 34 min is chosen to get a phase shift between temperature and switching period NOTE 2 The temperature requirements of A.1 do not apply
NOTE 3 LED modules without or with integrated heatsink maybe do not reach the maximum rated t p temperature at + 50 °C test chamber temperature
General
All measurements must be conducted in a draught-free environment at a temperature of 25 °C, with a tolerance of ±1 °C, and a maximum relative humidity of 65% Additionally, the LED module should operate under steady state conditions during these measurements.
For air movement requirements, see 4.3.2 of CIE 1 21 :1 996
For temperature measurement, equipment as specified in the informative Annex H may be used
Maintenance and supply switching operations must occur within the temperature range of \( t_{p \, \text{rated}} - 5 \) to \( t_{p \, \text{rated}} \) at the manufacturer's specified maximum ambient temperature, allowing for a tolerance of (+0 K, -5 K) If no maximum ambient temperature is provided, a range of 20 °C to 25 °C should be used The temperature requirement for the supply switching test applies only during the ON time, and the \( t_{p \, \text{rated}} \) value must not be exceeded To achieve the correct \( t_{p \, \text{rated}} \), appropriate heat sinks or additional heating may be necessary For testing, the \( t_{p} \) point should be clearly marked and easily accessible, and while \( t_{p} \) and \( t_{c} \) may be located differently, the \( t_{c} \) value must also not be exceeded.
All test results must be presented as if conducted at the maximum recommended operating temperature (t p rated) of the LED module Testing may occur at various temperatures, but the relationship between t p rated and any other temperature must be clearly defined using data from the LED module manufacturer If there is uncertainty, reference measurements should be taken at t p rated Additionally, the t p measurement should be conducted under the most demanding operational conditions, depending on the control circuit used by the manufacturer The value of t p rated will be reported in Clause 4.
The manufacturer shall provide, on request, information on the method used to reproduce the claimed characteristics declared at t p -point
The test voltage, current, or power must remain stable within ± 0.5% during stabilization periods, with a tighter tolerance of ± 0.2% during measurements For aging and luminous flux maintenance testing, a tolerance of 2% is acceptable Additionally, the total harmonic content of the input should not exceed 3%, defined as the r.m.s summation of individual harmonic components with the fundamental set at 100% All tests must be conducted at the rated frequency, and for ranges, measurements should be taken at the frequency that has the most adverse effect on the temperature of the LED module.
For stabilisation, the following steps need to be conducted
1 ) Ascertain that the LED module has thermal management, either integrated or externally equipped
2) Operate the LED module and record the light output as a time depending variable and note the typical electrical mode of operation (by voltage, current or power)
During the stabilization period, light output measurements are taken at intervals of at least one minute An LED module can be considered stable and appropriate for testing if the difference between the maximum and minimum light output readings over the last 15 minutes is less than 0.5%.
If stabilisation conditions are not achieved within 45 min the measurement may be started and the observed fluctuations shall be reported
To expedite the measurement process for additional LED modules of the same type, a pre-stabilization phase can be implemented This involves operating the light source before it is mounted in the test system, based on the stabilization time noted in step 3 Consequently, subsequent LED modules can be measured after just 15 minutes in the test system.
The stabilization process typically involves a gradual reduction in light output until thermal stability is achieved However, fluctuations may still arise near this stability point, indicating that stabilization criteria have not been fully met Additionally, the conditions for stabilization may evolve with the implementation of a relevant CIE standard.
Unless otherwise specified for a specific purpose by the manufacturer or responsible vendor, LED modules shall be operated in free air for all tests including lumen maintenance tests
To ensure accurate measurements during life tests, it is essential that the test sample remains uncontaminated by pollutants such as dust throughout the testing period.
Electrical characteristics
Test voltage, current or power
The test voltage, current, or power must align with the rated specifications, as outlined in section A.1 for tolerance When dealing with a range, measurements should be taken at the input value that has the most significant impact on the temperature of the LED module.
Ageing
LED modules do not require any ageing prior to testing However, the manufacturer may define an ageing period of up to 500 h.
Photometric characteristics
Test voltage, current or power
Luminous flux
The initial and maintained luminous flux shall be measured after stabilisation of the LED module
NOTE 1 Method of measuring the luminous flux of LED modules is under consideration
NOTE 2 Reference is made to document CIE 84 IES LM-79-08 as well as Annex B of JIS C 81 55: 201 0 contain valuable information on measuring luminous flux
To ensure optimal performance of the LED module, it is essential to implement additional heating or heat sinking in the measurement setup to maintain the specified temperature at \$t_p\$ Manufacturers should be prepared to provide information upon request regarding the methods used to achieve the claimed characteristics at this temperature.
Luminous intensity distribution
Luminous intensity distribution shall be measured in accordance with CIE 1 21 and IEC TR 61 341
Luminous intensity distribution data must be provided for all variations of the LED module, including any specified optical attachments or accessories This data should adhere to an established international or regional format, as outlined in IEC 62722-1, Annex A, for informative purposes.
Information about photometric data and file formats can be found in IEC 62722-1 (in preparation), Clause 6 and Annex A, for informative (not normative) purposes.
Peak intensity
The peak intensity shall be measured in accordance with IEC TR 61 341
Beam angle
The beam angle shall be measured in accordance with IEC TR 61 341
It should be taken care that the beam angle is not determined by the half peak, but by the half centre beam intensity.
Colour rendering
Measurement of colour rendering index shall be made in accordance to CIE 1 3.3 and CIE 1 77.
Chromaticity coordinate values
Reference shall be made to IEC 60081 , Annex D: Chromaticity coordinates
The chromaticity coordinate values of LED modules can vary based on the radiation angle It is essential to use spatially averaged chromaticity coordinates unless the manufacturer specifies otherwise This averaging can be achieved through sphere photometry or other approved methods.
Annex B (informative) Information for luminaire design
Temperature stability
It should be safeguarded that the LED module performance temperature t p is not exceeded.
Binning procedure of white colour LEDs
Ingress protection
When a 'built-in' LED module is integrated into the luminaire enclosure and used in an application with a specific IP classification, the specifications of the LED module must align with this classification The final evaluation will be conducted on the luminaire itself.
The LED module design with regard to IP rating should be specified between the LED module maker and the LED luminaire maker
An “independent” classified LED module should be tested to the specified IP rating according to IEC 60598-1
LED modules, classified as “‘integral” should not be separately tested.
Annex C (informative)Explanation of recommended LED procuct lifetime metrics
General
The lifespan of an individual LED module is defined as the duration it maintains at least x% of its initial luminous flux under standard test conditions An LED module can reach the end of its life due to both gradual performance decline and sudden failures, resulting in either operational or non-operational states.
NOTE For better readability, the term LED product is used which has to be considered as LED based lighting product
An abrupt failure of a LED module signifies a complete module failure rather than an issue with individual LED packages In contrast, the failure of single LED packages typically leads to a gradual decline in the overall light output of the module When the light output falls below a specified percentage, it is classified as a parametric failure Figure C.1 illustrates the differences between gradual and abrupt failure modes in a luminaire that consists of a single LED module.
* Overall lumen depreciation includes also optical parts degradation of the LED luminaire; gradual lumen depreciation below x percent leads to a parametric failure
Figure C.1 – Lumen output over life of a LED-based luminaire comprised of a single LED module
The lifespan of LED products often exceeds what can be practically verified through testing, and the reduction in light output varies by manufacturer, complicating general predictions To address this, lumen maintenance codes have been established to account for the decrease in luminous flux over a specified operational time However, due to the limited duration of testing, the claimed lifespan of an LED product cannot be definitively confirmed or denied The recommended metrics for specifying LED product life are outlined below, providing the necessary background for the pass/fail criteria of the lifetime test.
It is recommended for LED products to specify the lumen maintenance apart from the abrupt failures in a standardised way giving more insight in light output behaviour
Life time specification for gradual light output degradation
The useful life, denoted as L x B y, refers to the duration until a percentage y of operating LED modules experiences a gradual light output degradation of percentage x.
A parametric failure occurs when light output falls below the lumen maintenance factor x, indicating that the product emits less light while still functioning The "B10 life" refers to the age at which 10% of products experience parametric failure, while the "B50 life," or median useful life, is the age at which 50% of LED modules fail parametrically It is important to note that this analysis only includes operating LED modules, excluding any non-operative units.
Example: L x B y = L 70 B 1 0 is understood as the length of time during which 1 0 % (B 1 0 ) of a population of operating LED modules of the same type have failed (parametrically) to maintain
70 % of their initial luminous flux
Figure C.2 – Life time specification for gradual light output degradation
The probability density function (pdf) can take various forms, such as Weibull, lognormal, exponential, or normal, depending on the measured data and the chosen projection method The shapes of the pdf and the projection curve shown in Figure C.2 are for illustrative purposes only.
The failure function F(t) or Cumulative Distribution Function (CDF(t)), is the failure percentile as function of time This is mathematically expressed as follows:
1 0 % percentile (time at which F ( t ) = 0,1 ) Measured data
Projection curve individual LED product
Lumen maintenance curve, connecting the B 50 points ( B 50 is 50 % percentile or median)
B expresses percentile gradual light output degradation
By definition F(t=infinite) is 1 (1 00 %) In other words the total area below the pdf curve from time is zero to infinity is one, meaning the whole population fails eventually
Example: Considering a lumen maintenance factor x of 70 %, 1 0 % of the population failed at time L 70 B 1 0 indicated by the grey area in Figure C.2, mathematical expressed as follows:
The reliability function equals: R(t)=1−F(t), expressing reliability.
Lifetime specification for abrupt light output degradation
The time to abrupt failure, denoted as C y, refers to the duration until a specific percentage y of LED modules experiences sudden light output degradation This metric indicates the age at which a certain percentage of LED modules have failed abruptly, as illustrated in Figure C.3.
C 1 0 refers to the duration in which 10% of initially functioning LED modules of the same type cease to emit any light.
Combined gradual and abrupt light output degradation
The length of time until a percentage y of a population of LED lamps reaches combined gradual and abrupt light output degradation, meaning the LED lamps have either
50 % fa ilu re s 90 % fa ilu re s
R abrupt parametrically failed, no longer producing at least x % of their initial luminous flux, or abruptly failed, is called the LED Lamp Life (or “F y life”) and expressed as M x F y
The equation M x F y = L 70 F 1 0 represents the duration in which 10% (F 1 0) of a specific population of LED lamps has failed, either through parametric or abrupt failure modes, resulting in a reduction of luminous flux to below 70% of their original output or complete loss of light.
The “F 50 life”, is defined as the median LED lamp life and called M x
The combined gradual and abrupt light output degradation can be constructed from the above two specifications via reliability curves in three steps
Step 1 : Reliability curve for parametric failures due to gradual light output degradation (see Figure C.4)
Figure C.4 – Reliability curve R gradual for gradual light output degradation Step 2: Reliability curve for abrupt light output degradation (see Figure C.3)
The reliability curve in Figure C.3 expresses also the survivals of the LED products
Step 3: Reliability curve for combined degradation (see Figure C.5)
50 % fa ilu re s 90 % fa ilu re s
Overview of LED lifetime metrics and related lighting product groups
In the lighting industry, various lifetime metrics are utilized to effectively communicate with different end users For general consumers using LED lamps, providing the median life based on combined failure criteria, which includes both abrupt and parametric failures, is typically sufficient However, professional customers in the lighting market often require separate estimates for time to failure functions, encompassing both abrupt failures and luminous flux maintenance These detailed values enable them to perform calculations for lighting installations, including maintenance cycle estimations.
Figure C.6 provides an overview of various lifetime metrics discussed in this annex, along with related products The upper frame A highlights quantities from failure functions that are particularly relevant to professionals, while the lower frame B presents simpler quantities intended for general market communication.
Co m bi ne d Fa ilu re Va lu e ( C F V )
Figure C.6 – Overview of LED lifetime metrics
Example lifetime metric values
The introduction of the median useful life \( L_x \), the abrupt failure value, and the median LED lamp life offers a complete set of definitions for effectively communicating lifetime-related specifications for LED products.
When specifying different values, see Tables C.1 , C.2 and C.3 below for example values Individual LED packages or LED dies within a LED product are not addressed
In various LED products, the lifetime metrics are interconnected; typically, as the lumen maintenance factor rating rises, the rated life and AFV values tend to decline.
NOTE LED modules with constant lumen output are under consideration
Table C.1 – Example lifetime metric values for lumen maintenance factor ratings numbers in %
Standard set of B: quantities for communication to market
General set of A: lifetime metrics for providing product data
LED luminaires LED lamps combined gradual and abrupt light output degradation
LED Lamp Life ( M x F y ) nb hrs at x % of light including abrupt failures with y % of the population failed named:
The median life of LED lamps, denoted as \( M_x \), represents the number of hours at which 50% of the population experiences light output at \( x\% \), accounting for both abrupt and gradual failures This metric is crucial for understanding the performance and longevity of LED lighting, particularly at the rated maximum usable life (MUL).
Time to Abrupt Failure ( C y ) nb hrs at y % abrupt failures
Useful Life ( L x B y ) nb hrs at x % light with y % of the population failed
Median Useful Life ( L x ) nb hrs at x % light for 50 % of the population
% abrupt failures at L x at rated MUL named:
Table C.2 – Example lifetime metric values for abrupt failure numbers in %
Table C.3 – Example lifetime metric values of x for median LED lamp life (combined failures) numbers in %
Table C.4 – Example lifetime metric values x (%) 70 80 90
Annex D (normative) Explanation of the photometric code
Example of photometric code like 830/359, meaning:
– initial spread of chromaticity coordinates within a 3-step
MacAdam ellipse – maintained spread of chromaticity coordinates at 25 % of rated life
(with a maximum duration of 6 000 h) within a 5-step MacAdam ellipse – code of lumen maintenance at 25 % of rated life (with a maximum duration of 6 000 h), in this example: ≥90 % of the 0 h value
The colour rendering value is expressed as one figure which is obtained by using the intervals:
NOTE In Japan, the requirements on colour classification and indication is specified in JIS Z 91 1 2
Annex E (normative) Measurement of displacement factor
General
The phase shift angle (φ 1 ) of the displacement factor (cos(φ 1 )) of 7.2 shall be measured according to the definition of E.2 and with the measurement requirements of Clause E.3
Phase shift angle definition
The phase shift angle φ 1 between the fundamental (I 1 ) harmonic current and the mains voltage (U mains ) is determined as described in Figures E.1 and E.2:
Figure E.1 – Definition of the fundamental current phase shift angle φ 1
Figure E.2 – Definition of the fundamental current phase shift angle φ 1
Measurements requirements
Measurement circuit and supply source
The measurement circuit and the supply source are defined in Annex A of IEC 61 000-3-2:2005.
Requirements for measurement equipment
The requirements for measurement equipment are defined in IEC 61 000-4-7.
Test conditions
The test conditions for the measurements of the displacement / phase-angle associated with some types of equipment are given in the following clause: see C.5 of IEC 61 000-3- 2:2005/AMD 2:2009
NOTE Test conditions for LED light sources in IEC 61 000-3-2:2005, C.5 are under consideration
Annex F (informative) Explanation of displacement factor
General
The metric power factor (l) is a composite metric and consists of the primary metrics displacement factor (κdisplacement) and distortion factor (κ distortion )
The relation between the composite metric l and its primary metrics κdisplacement and κ distortion is as follows: distortion nt displaceme κ κ l= ⋅ with
The phase shift angle ϕ 1 represents the difference between the fundamental components of the supply voltage and the mains current Total harmonic distortion (THD) is measured based on the harmonics present in the mains current, as specified by IEC 61 000-3-2 The relationship between the individual harmonics of the mains current and the THD is described by a specific equation.
I n is the amplitude of the n th harmonic of the mains current.
Recommended values for displacement factor
No negative effects on the power grid are to be expected from integrated LED modules (Type
1 ) when complying with the recommendation as in Table F.1
Table F.1 – Recommended values for displacement factor
Metric P ≤ 2 W 2 W < P ≤ 5 W 5 W < P ≤ 25 W P > 25 W κ di spl acemen t (cos ϕ 1 ) No limit ≥ 0,4 ≥ 0,7 ≥ 0,9
The values are practical examples and give guidance
Annex G (informative) Examples of LED dies and LED packages
LED die
Schematic examples of LED dies are given in Figure G.1
1 n-GaN 5 MQW active region (Multi
Quantum Well) 9 intermediate conducting substrate/submount
2 p-GaN 6 roughened n-GaN 1 0 submount/package
3 metal anode/cathode contacts 7 sapphire 1 1 submount/package
4 patterned n-contact 8 wire bond 1 2 package a) Thin-film-flip-chip LED b) Flip-chip LED c) Vertical thin-film-chip LED
Figure G.1 – Schematic drawings of LED dies
LED package
Schematic examples of LED packages are given in Figure G.2
2 Printed Circuit Board (PCB) 6 Heat sink
4 Die attach 8 Copper tracks a) Surface mounted LED package with lead wires
2 Printed Circuit Board (PCB) 6 thermal pad
4 LED die 8 copper tracks b) Surface mounted LED package without lead wires
Figure G.2 – Schematic drawings of LED packages
Annex H (informative) Test equipment for temperature measurement
General
This article provides recommendations for measuring temperature on LED modules within a draught-proof enclosure, based on IEC 60598-1, Annex K It emphasizes that while specific measurement methods are preferred for their precision and accuracy, alternative methods may be utilized if they demonstrate comparable performance.
normative) Use of IES LM-80 for lumen maintenance, colour rendering index
General
The LED module's initial and maintained values are assessed based on chromaticity coordinates (9.1), Color Rendering Index (CRI) (9.3), and lumen maintenance (10.2) To minimize testing time for maintained values at 25% of rated life (up to 6,000 hours), data from IES LM-80 can be utilized, provided that the conditions outlined in Clause I.2 and the compliance criteria in Clause I.3 are satisfied.
If the LED module and LED package have not undergone testing per IES LM-80, it is essential to complete the full testing duration as specified by this International Standard.
Criteria for the use of IES LM-80
I.2.1 LED package data used for LED modules
If data from an IES LM-80 test report applied to an LED package is available, the test conditions in 6.1 are applicable for LED modules with a test duration of 1 000 h
For compliance criteria after 1 000 h testing, see Clause I 3
I.2.2 LED module with IES LM-80 data
If the LED module has been tested in accordance with IES LM-80 including CRI, the test duration of 6.1 may be avoided
The chromaticity data, CRI, and lumen maintenance at 25% of rated life, with a maximum of 6,000 hours, must be sourced from the IES LM-80 test report to meet the maintained value requirements outlined in sections 9.1, 9.3, and 10.2.
The combination of the selected maximum r.m.s input current and maximum solder temperature from the IES LM-80 report shall represent the worst case condition of the LED module
All performance data for this standard is associated with the reference temperature \( t_p \) rated on the LED module The rated temperature \( t_{p,\text{rated}} \) is measured at the reference location, known as the \( t_p \)-point, as defined by the manufacturer.
The LED module must operate at its specified temperature, \( t_p \), while the case temperature of the LED package, \( T_s \), should be measured according to IES LM-80 standards It is crucial that the maximum recorded value of \( T_s \) within the LED module does not surpass the temperature limit established in the IES LM-80 report.
In case of an LED module family according to Table 4, the T s temperature measurement shall be performed with the LED module configuration that results in the highest T s temperature
The maximum r.m.s input current of the LED package in the LED module shall not exceed the r.m.s input current that was tested as a part of the IES LM-80 test
In applications utilizing IES LM-80 for lumen maintenance and chromaticity coordinates data, it is essential to disable any control circuits in the control gear that automate the compensation for light output degradation over time.
Compliance criteria
LED modules tested per section 9.1, with a maintained test duration as outlined in I.2.1, must comply with the initial color variation category specified by the manufacturer or responsible vendor, as indicated in Table 5.
LED modules tested in accordance with section 9.3, with a maintained test duration as outlined in I.2.1, must achieve a Color Rendering Index (CRI) value that is no more than 3 points lower than the value declared by the manufacturer or responsible vendor, as specified in Table 1.
LED modules evaluated according to 10 2 with a maintained test duration as specified in I.2.1 shall meet the lumen maintenance code as declared by the manufacturer or responsible vendor according to Table 6
IEC 60598-1 , Luminaires – Part 1: General requirements and tests
IEC 62384, DC or AC supplied electronic controlgear for LED modules – Performance requirements
IEC 6261 2:201 3, Self-ballasted LED lamps for general lighting services with supply voltages >
IEC 62707-1 , LED-binning – Part 1: General requirements and white colour grid
IEC 62722-1 9 , Luminaire performance – Part 1: General requirements
IEC PAS 62722-2-1 , Luminaire performance – Part 2-1: Particular requirements for LED luminaires
CISPR 1 5:2005, 1 0 Limits and methods of measurement of radio disturbance characteristics of electrical lighting and similar equipment
CIE 84:1 989, The Measurement of Luminous Flux
IES LM-79-08, Electrical and photometric measurements of solid state lighting products
JIS C 81 55:201 0, LED modules for general lighting service – Performance requirements
JIS Z 91 1 2:201 2, Classification of fluorescent lamps and solid state lighting products by chromaticity and colour rendering property
Journal of the Optical Society of America, 1 943
1 0 Seventh edition This edition has been replaced in 201 3 by CISPR 1 5:201 3, Limits and methods of measurement of radio disturbance characteristics of electrical lighting and similar equipment
4 Marquage 64 4.1 Marquage obligatoire 64 4.2 Marquage additionnel 65
The article discusses six testing conditions, beginning with general testing conditions It emphasizes the creation of LED module families to minimize testing efforts, detailing the general principles, variations within a family, and compliance testing for family members.
7 Entrée électrique du module de LED 68 7.1 Puissance du module de LED 68 7.2 Facteur de déphasage (u.c.) 68
The article discusses standardized luminous efficiency, focusing on key aspects such as luminous flux, light intensity distribution, maximum intensity, and beam angle It provides general information on these topics, measurement techniques, and details on light intensity distribution, maximum intensity values, and beam angle values Additionally, it covers the concept of luminous efficacy, emphasizing its importance in evaluating lighting performance.
9 Coordonnées trichromatiques, température de couleur proximale (CCT) et rendu des couleurs 69 9.1 Coordonnées trichromatiques 69 9.2 Température de couleur proximale (CCT) 70 9.3 Indice de rendu des couleurs (IRC) 71
1 0 Durée de vie du module de LED 71
1 0.3.2 Essai de cycles de températures 73
1 0.3.4 Essai accéléré de durée de fonctionnement 75
1 2 Informations relatives à la conception du luminaire 76
Annex A outlines the measurement methods for LED module characteristics, including electrical and photometric properties Key electrical characteristics include testing voltage, current, and power, as well as aging effects Photometric characteristics cover testing voltage, luminous flux, intensity distribution, maximum intensity, beam angle, color rendering, and trichromatic coordinate values Annex B provides design information for luminaires, focusing on temperature stability, color binning procedures for white LEDs, and LED module protection ratings Annex C explains recommended methods for measuring LED product lifespan, detailing specifications for gradual and sudden luminous efficacy degradation, combined degradation, and an overview of measurement methods with example lifespan values Annex D presents the photometric code explanation, while Annex E discusses phase factor measurement, including definitions, measurement requirements, and testing conditions Annex F elaborates on the phase factor, providing recommended values Annex G offers examples of LED chips and encapsulated LEDs, and Annex H details testing equipment for temperature measurement, including setup and procedures Finally, Annex I addresses the use of IES LM-80 for maintaining luminous flux, color rendering index, and trichromatic coordinate data.
I.1 Généralités 98 I.2 Critères relatifs à l'utilisation de l'IES LM-80 98 I.2.1 Données de LED encapsulées utilisées pour les modules de LED 98 I.2.2 Module de LED avec données de l'IES LM-80 98 I.2.3 Conditions limites 98 I.3 Critères de conformité 99 I.3.1 Coordonnées trichromatiques 99 I.3.2 Indice de rendu des couleurs (IRC) 99 I.3.3 Facteur de conservation du flux lumineux 99 Bibliographie 1 00
The article presents various figures related to LED technology, including types of LED modules and their luminous flux depreciation over time It highlights the luminous efficiency of single LED modules throughout their lifespan and specifies the life expectancy for gradual degradation of normalized luminous efficiency Additionally, it includes reliability curves for both abrupt and progressive degradation of luminous efficiency, as well as a combined degradation analysis The article also provides an overview of methods for measuring LED lifespan and defines the phase angle of the fundamental current in relation to the mains current, illustrating both leading and lagging scenarios Finally, it features schematic drawings of LED chips and encapsulated LEDs.
The article includes essential tables detailing mandatory and optional markings for LED modules, lifespan information, and variations within families Key tables cover tolerances for trichromatic coordinates, luminous flux maintenance codes, and sample sizes Additionally, examples of lifespan measurement values for maintenance factors, sudden failures, and median lifespan of LED lamps are provided Recommended values for the phase factor are also included, ensuring comprehensive guidance on LED module specifications and performance metrics.
MODULES DE LED POUR ÉCLAIRAGE GÉNÉRAL –
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