LUMILEDS AN1149-4

application brief AB204
replaces AN11494
Thermal Management
Considerations for SuperFlux LEDs
Thermal management is critical in the design of LED signal lamps because temperature affects
LED performance and reliability. The following section details the effects of temperature on
LEDs. In addition, thermal measurement techniques of LED signal lamps and recommended
design practices for proper thermal management are covered.
Table of Contents
Importance of Thermal Management
for High-Power LED Assemblies
Temperature Induced Effects on LED Light Output
Change in Dominant Wavelength (Color) as a Function
Of Junction Temperature
TemperatureInduced Failures of LEDs
Thermal Modeling of LED Assemblies
Thermal Resistance of LED Automotive Signal Lamps
JunctiontoAmbient Thermal Resistance Measurement Procedure
JunctiontoAmbient Thermal Resistance Measurement
Estimating JunctiontoAmbient Thermal Resistance
Evaluating Junction Temperature and Forward Current
Light Output and Forward Current
Derating Example Cases
Recommended Design Practices for Proper Thermal Management
PCB Design
Maximum Metallization
LED Spacing
Lamp Housing Design and Mounting of the LED Array
Circuit Design
Current Control
Power Dissipation
“Switching” Power Supplies
Ambient Temperature Compensation
Appendix 4A
Alternate JunctiontoAmbient Thermal Resistance
Measurement Procedure
2
2
2
3
4
4
5
5
6
6
7
7
8
8
8
9
9
10
10
10
11
11
12
12
Importance of Thermal Management
for HighPower LED Assemblies
Temperature Induced Effects on LED Light Output
The junction temperature of the LED affects the
Typical temperature coefficients for various high
device’s luminous flux, the color of the device,
brightness LEDs are listed in Table 4.1.
and its forward voltage. Junction temperature
can be affected by the ambient temperature
The degradation of flux as a function of
and by selfheating due to electrical power
increasing temperature for a typical redorange,
dissipation.
absorbingsubstrate (AS) or transparent
substrate (TS) AlInGaP LED is shown in Figure
The equation for luminous flux as a function of
4.1. Note, luminous flux has been normalized at
temperature (°C) is given below:
25°C.
ΦV (T2) = Φ V (T1)e
–k∆Tj
This graph shows the profound affect that
temperatures within the normal operating
Where:
guidelines can have on luminous flux. As shown,
ΦV (T1)= luminous flux at junction temperature T1
ΦV (T2)= luminous flux at junction temperature T2
an increase in the junction temperature of 75°C
can cause the level of luminous flux to be
k = temperature coefficient
reduced to onehalf of its room temperature
∆Tj = change in junction temperature (T2 T1).
value. From this, it is clear that temperature
effects on luminous flux must be accounted for
in the design of a LED assembly.
Table 4.1
Temperature Coefficient for High-Brightness LED Materials.
LED Material Type
Temperature Coefficient, k
AS AlInGap, Red-Orange
AS AlInGap, Amber
TS AlInGap, Red-Orange
TS AlInGap, Amber
9.52
1.11
9.52
9.52
x
x
x
x
10-3
10-2
10-3
10-2
Figure 4.1 Luminous flux versus ambient
temperature for a typical red-orange AS/TS AlInGap
LED when operated at a constant current.
Change in Dominant Wave-length (Color) as a Function
of Junction Temperature
The junction temperature of LEDs also affects
A rule that is easy to remember is the dominant
their dominant wavelength, or perceived color.
wavelength will increase one nanometer for every
10°C rise in junction temperature. In most
The equation for dominant wavelength, λd , as
designs of red automotive signal lamps, this
a function of temperature is:
change in color is not important because the
allowed color range is very large (approximately
90 nm). However, for some amber automotive
Where:
signal lamps, this color shift can be a concern
λd (T1)= dominant wavelength at junction
and should be accounted for where the allowed
temperature T1
color ranges are small (approximately 5 to 10 nm
λd (T2)= dominant wavelength at junction
depending on the regional specifications).
temperature T2
Temperature-Induced Failures of LEDs
LEDs are typically encapsulated in an optically
epoxy encapsulant to expand and contract more
clear epoxy resin. At a certain elevated
during temperature changes. This causes more
temperature, known as the glass transition
displacement of the wire bond within the LED
temperature, Tg, these epoxy resins transform
package, resulting in a premature wearout and
from a rigid, glasslike solid to a rubbery
breakage of the wire. Wire bond breakage results
material. A dramatic change in the coefficient of
in an open failure.
thermal expansion (CTE) is generally associated
with the Tg. The Tg is calculated as the midpoint
of the temperature range at which this change
in CTE occurs, see Figure 4.2.
To avoid catastrophic failure of LED packages,
the junction temperature, Tj , should always be
kept below the Tg of the epoxy encapsulant.
Lumileds specifies a maximum junction
temperature, Tj (max) , which is below the Tg of the
Figure 4.2 Expansion-Temperature relationship for
clear, epoxy, LED encapsulants.
epoxy encapsulant used. For SuperFlux LEDs,
Tj (max) = 125 °C. If the Tj (max) is exceeded, the CTE
of the epoxy encapsulant will permanently and
dramatically change. A higher CTE causes the
3
Thermal Modeling of LED Assemblies
Thermal Resistance of LED Automotive Signal Lamps
Thermal resistance is associated with the
Assuming all the electrical power is dissipated in
conduction of heat, just as electrical resistance
the form of heat (approximately 5to10% of the
is associated with the conduction of electricity.
power is dissipated optically), the equation for
Defining resistance as the ratio of driving
junctiontopin thermal resistance (Rθjp) of an LED
potential to the corresponding transfer rate,
can be written in the form of the equation below:
thermal resistance for conduction can be
defined as shown in the equation below:
_
Where:
P = the total electrical power into the LED (If * Vf)
Where:
Rθ = thermal resistance between two points
For LED lamp assemblies, the equation for
∆T = temperature difference between those
junctiontoambient thermal resistance, Rθja,
of an individual LED within the assembly can
two points
be written as:
qX = rate of heat transfer between those two
points
The thermal resistance of an LED signal lamp
Where Tj = ∆Tj + Ta .
(junctiontoambient thermal resistance, or Rθja )
is made up of two primary components: the
As can be seen from this equation, in order to
thermal resistance of the LED package
determine Rθja of an LED within a lamp assembly,
(junctiontopin thermal resistance, or Rθjp ) and
the rise in junction temperature, and the electrical
the thermal resistance of the lamp housing (pin
power into the device must be determined. The
electrical power into the LED under test can
toambient thermal resistance, or Rθpa ). These
easily be determined by multiplying its forward
two components of thermal resistance are in a
current and forward voltage. The rise in junction
series configuration, therefore:
Rθjp +
(LED emitter)
Rθpa
(lamp housing)
=
temperature can be determined by measuring
Rθja
the change in forward voltage of the LED under
test.
(LED signal lamp)
This is shown graphically in Figure 4.3.
4
Figure 4.3 Graphic representation of the components
of thermal resistance.
Junction-to-Ambient Thermal Resistance Measurement Procedure
A simple method for measuring the Rθja of a lamp
Step 4: Assemble the modified PCB into the lamp housing
assembly is possible by assuming the Rθjp of the device
such that the thermocouple wires are extending
under test (DUT) is of a typical value. By making this
outside the lamp.
assumption, only the pin-to-ambient thermal resistance,
Step 5: Energize the entire lamp assembly at the design
Rθpa , needs to be measured to calculate the Rθja of the
lamp (Rθja = Rθjp + Rθpa). This simplified procedure for
voltage for a minimum of 30 minutes. This will allow
measuring Rθja is described below:
the lamp assembly to thermally stabilize.
Step 6: Measure the pin temperature of the DUT along with
Step 1: Assume the Rθjp of the LED emitter is that shown
the ambient temperature in the room.
in the data sheet (typical Rθja for HPWA-xx00 =
155 °C/W, and for HPWT-xx00 = 125 °C/W).
Step 7: Calculate the Rθpa of the lamp assembly using the
following equation:
Step 2: Pick one LED within the assembly to be used as
Tp - Ta
the DUT. The hottest LED in the assembly should
Rθpa =
be chosen, for example an LED in the middle of
the assembly and next to a resistor.
P
Where the power, P, into the DUT is calculated by
multiplying the heating/design current by its
Step 3: Solder a small thermocouple (approximately 0.25
corresponding forward voltage.
mm in diameter) onto one of the cathode leads of
the DUT near the top surface of the PCB. Large
Step 8: Calculate the Rθja of the lamp assembly by adding
thermocouples, which can alter the thermal
the Rθjp of the emitter from Step 1 to Rθpa from
properties of the DUT, should be avoided.
Step 7.
Junction-to-Ambient Thermal Resistance Measurement
These sections give detailed instructions on
not available. An alternate method for measuring
how to perform thermal resistance
thermal resistance is provided in Appendix 4A.
measurements on LED assemblies. The first
This method monitors the change in forward
method described in the box above, Junction
voltage of the LED to determine the change in
toAmbient Thermal Resistance Measurement
junction temperature and thermal resistance.
Procedure, allows for simple measurements to
This method requires an elaborate test setup and
be made on lamp assemblies without an
precise measurements. This technique is
elaborate test setup. The second method
commonly used by Lumileds Lighting.
presented, Estimating JunctiontoAmbient
Thermal Resistance, eliminates the need for
Lumileds will evaluate the thermal resistance of
measured thermal resistance. This type of
LED assemblies and signal lamps upon request.
estimation is ideal for early evaluations, where
Please contact your local applications engineer
an actual prototype and/or test equipment is
for information.
5
Table 4.2
Typical Rθja Values for the Classes of LED Lamp Assemblies
Typical Rθja (°C/W)
LED Lamp Classification
Class
Class
Class
Class
1
2
3
4
325
400
500
650
Estimating Junction-to-Ambient Thermal Resistance
Class 3: Multiple rows, or an x-y arrangement, of LEDs with
The procedures described in Junction-to-Ambient Thermal
Resistance Measurement Procedure are accurate
the current-limiting resistors/ drive circuitry located
methods for determining the Rθja of an LED within a
off of the PCB, either in the wire harness assembly
plastic lamp assembly. However, in some cases, the time
or on a separate PCB.
and/or equipment may not be available to perform such
Class 4: Multiple rows, or an x-y arrangement, of LEDs with
testing. In these cases, an educated estimate may be the
best method available. Lumileds has developed some
the current-limiting resistors/ drive circuitry located
basic classifications of LED lamp assemblies and
on the same PCB as the LEDs. This is the most
corresponding Rθja estimates. Below is an explanation
common situation for LED rear combination lamp
of the different classes, and the Rθja estimates.
applications.
Table 4.2: lists the typical Rθja values for each class of LED
Class 1: Single row of LEDs with the current-limiting
resistors/drive circuitry located off of the PCB,
lamp assembly listed above. These are only
either in the wire harness assembly or on a
estimates and should not be used for detailed,
separate PCB.
worst-case analyses.
Class 2: Single row of LEDs with the current-limiting
resistors/drive circuitry located on the same PCB
as the LEDs. This is the most common situation
for LED CHMSL assemblies.
Evaluation Junction Temperature and Forward Current
The primary concern when evaluating the
Tj = (Rθ ja. P LED) + Ta
thermal characteristics of an LED assembly
Tj = (Rθ ja. If LED . Vf LED) + Ta
is to ensure that the junction temperature of
the LEDs is kept below the specified maximum
Typical values for Ta(max) are shown in Table 4.3.
value (125 °C for SuperFlux LEDs). There are
three factors which determine junction
To determine the worstcase, highest junction
temperature: 1) ambient temperature, 2) Rθ ja,
temperature, this equation becomes:
and 3) power into the LED. Below is a sample
Tj max = (Rθ ja. P LED max ) + Ta max
junction temperature calculation, which
Tjmax = (Rθ ja. If max . Vf max ) + Ta max
illustrates how these three factors interact:
Tjmax ≤ 125°C
6
Lumileds plots these curves for different values
referred to as the derating curves. The derating
of Rθ ja along with their intersection with the
curves for HPWTxx00 devices, are shown in
maximum drive current of 70 mA, and their
Figure 4.4. Derating curves for HPWAxx00
intersection with the maximum ambient
devices are provided in the SuperFlux LED
temperature of 100 °C and includes this graph
Technical Data Sheet. Refer to sidebar Derating
in all LED data sheets. This graph is typically
Example Cases for further explanation.
Light Output and Forward Current
The relationship between light output and
decrease as forward current is increased. For
forward current for different thermal resistances
assemblies with high Rθ ja, a great deal of heating
is shown in Figure 4.5. For LED assemblies with
occurs resulting in high junction temperatures.
low thermal resistances (Rθ ja = 200 °C/W), the
In these cases, the effects of increasing junction
relative flux increases almost proportionally to
temperature can offset the effects of increasing
the forward current. However, for LED
forward current. Proper thermal management
assemblies with high thermal resistances
and drive current selection is critical to
(Rθ ja = 600 °C/W), the relative flux can actually
maximizing the performance of LEDs.
Derating Example Cases
Case 1—Class 1 LED CHMSL
From Table 4.2 the thermal resistance can be estimated
Consider an LED CHMSL application using 12 HPWT
as Rθja = 650 °C/W. Using Figure 4.4, the maximum
MH00 LEDs in a row, with a current limiting resistor in the
allowable forward current through each LED is 30 mA at
wire connector. The auto manufacturer has specified a
Ta(max) = 75 °C.
maximum ambient temperature of 75 °C.
As can be seen from these simplified sample cases, the
From Table 4.2 the thermal resistance can be estimated
Rθja has a major impact on junction temperature, and thus
as Rθja = 325 °C/W. Using Figure 4.4, the maximum
maximum allowable forward current. The different
allowable forward current through each LED is 55 mA
applications using the same LED have a difference in
at Ta (max) = 75 °C.
maximum forward current of nearly 2:1.
Case 2—Class 4 LED Rear Combination Lamp (RCL)
A more detailed determination of maximum forward current is
Consider an LED RCL application using 36 HPWTMH00
presented in Application Brief 203 Electrical Design
LEDs in a 6x6 pattern, with the drive circuitry on the same
Considerations for SuperFlux LEDs.
PCB as the LEDs. The auto manufacturer has specified a
maximum ambient temperature of 75 °C.
7
Recommended Design Practices for
Proper Thermal Management
PCB Design
Proper PCB design can reduce the Rθ ja of a
cathode leads of the LEDs are ideal. Very little
LED lamp assembly, and thus reduce the
heat is conducted through the anode leads of
junction temperature of the LEDs. Listed below
the LED, so additional metallization surrounding
are some recommended practices for the
these leads does not help.
design of LED PCBs.
Maximum Metallization
Conventional PCB design involves connecting
various points on the board with traces of
sufficient width to handle the current load. This
process is usually visualized as adding traces to
a blank PCB. For LED PCBs, this process
should be reversed—visualized as removing
metal only where needed to form the electrical
circuit. Large metal pads surrounding the
Figure 4.4 Graph of HPWT-xxOO Derating Curves.
Table 4.3
Typical Ta (max) Values for Automotive Signal Lamps
Typical Ta (max) (°C)
Application
Exterior-mounted signal lamp
Interior-mounted CHMSL
Interior, head-liner mounted CHMSL
Figure 4.5 Relative Luminous Flux vs. Forward
Current.
70
80
90
Figure 4.6 LED CHMSL PCB with proper
metallization and component placement.
8
The resistors should be located in a remote
minimized to prevent resistors from heating
portion of the PCB (away from the LEDs), on a
adjacent LEDs. This can be accomplished by
separate PCB, or in the wire harness if possible.
thinning down these traces, or by having
If this is not possible, the resistors should be
metallized areas contacting the LEDs and
distributed evenly along the PCB to distribute
resistors only contact the anode leads of the
the heat generated. In addition, the traces from
LED. A portion of an LED CHMSL PCB depicting
resistors to metallized areas surrounding
the design concepts discussed is shown in
cathode leads on the LEDs should be
Figure 4.6.
LED Spacing
Most of the electrical power in an LED is
optical constraints will allow. Most CHMSL
dissipated as heat. Tighter LED spacing
applications use only a single row of LEDs at
provides a smaller area for heat dissipation,
spacing greater than 15 mm which is ideal, as
resulting in higher PCB temperatures and thus
opposed to many amber turn signal applications
higher junction temperatures. The LEDs should
which use a tightly spaced (less than 10 mm) xy
be spaced as far apart as packaging and
array of LEDs.
Lamp Housing Design and Mounting of the LED Array
LED lamp housings should be designed to
PCB along its top and bottom edges to slots in
provide a conductive path from the backside of
the side of the lamp housing. Again, the area for
the PCB to the lamp housing. This is typically
conduction into the lamp housing is reduced to
accomplished by mounting the backside of the
the contact areas of the slots, which reduces the
PCB directly to the lamp housing such that they
effectiveness of conduction.
are contacting one another across the entire
length of the PCB. This mounting scheme can
If the PCB is mounted in such a way that
be improved by applying a thermally conductive
conduction to the lamp housing is not effective
pad between the PCB and the lamp housing.
(trapped air is a very poor conductor of heat),
The thermally conductive pad conforms to the
then allowances for convective cooling should be
features on the backside of the PCB and
made. The most common technique to take
provides a larger contact area for conduction.
advantage of natural convection is to put holes in
the top and bottom side of the lamp housing to
Often the PCB is mounted to the lamp housing
allow for vertical air flow over the PCB. However,
on top of raised bosses. In this case, the area
where the lamp housing must be sealed for
for conduction into the lamp housing is reduced
environmental reasons, this type of approach is
to the contact area on the top side of the
impractical.
bosses, greatly reducing its effectiveness.
Another common configuration mounts the
9
Circuit Design
Circuit design can help control the junction
temperature of the LEDs in two important ways:
1) minimize fluctuations in the drive current
(power input), and 2) dissipate a minimum
amount of heat, or dissipate heat in such a
way as to minimize its effect on the LEDs.
Figure 4.7 Schematic of a current control circuit for
LED automotive lamp applications.
Current Control
An ideal drive circuit will provide the same
current to the LEDs even as ambient
temperatures and battery voltages vary.
Inexpensive, simple current control circuits
can be designed to accomplish this task.
A schematic of such a circuit is shown in
Figure 4.7.
Current control circuits are often too expensive
Figure 4.8 LED forward current vs. battery voltage
for circuits of two, three, four and five LEDs in
series with a current limiting resistor.
and unnecessary for LED CHMSL applications.
The most common LED CHMSL drive circuit
consists of a current limiting resistor(s) and a
Power Dissipation
silicon diode for reverse voltage protection in
If the LED drive circuit is in a remote location
series with the LEDs. In this circuit design,
relative to the LEDs (in the wire harness or on a
the input current into the LEDs varies as the
separate PCB), then the power dissipated by the
battery voltage changes. The current control
drive circuit does not affect the junction
characteristics of this type of circuit improve
temperature of the LEDs. Drive circuit heating
as larger resistor/s are used with fewer LEDs
is a concern when the drive circuit is on the same
in series. However, circuits with fewer LEDs in
PCB as the LEDs. Drive circuit power dissipation,
series will have greater heat generation in the
and thus heat generation is inversely proportional
drive circuit. Figure 4.8 graphs the forward
to the number of LEDs in series. Circuits with
current provided to the LEDs vs. the input
fewer LEDs in series will have greater heat
battery voltage for resistor circuits with three,
generation in the drive circuit.
four, and five LEDs in series.
For most automotive applications in which the
For more information on picking the optimum
battery voltage is approximately 13 V, Lumileds
design current, and LED drive circuit for your
recommends configuring four LEDs in series. Four
application, please reference Application Brief
LEDs in series is a good compromise between
203 Electrical Design Considerations for
forward current control, heat generation, and
SuperFlux LEDs.
minimum turnon voltage for the LED array.
10
Ambient Temperature Compensation
Drive circuitry can be designed which
compensates for increasing ambient temperature
by decreasing the forward current to the LED
array. This allows the lamp designer to drive the
LED array at a higher forward current by reducing
the amount of current derating.
Figure 4.9 LED driver module for automotive
lighting applications.
Temperature compensation is achieved by
incorporating temperature sensitive components
“Switching” Power Supplies
into the drive circuitry, such as positive
Current sources, which operate efficiently over a
temperature coefficient (PTC) resistors. An
wide range on input voltages, can be designed
example of the resistance vs. temperature
using pulsewidth modulation (PWM) circuitry.
characteristics of a PTC resistor is shown in
Such circuits have the advantage of low heat
Figure 4.10.
dissipation, and large input voltage compliance.
This type of power supply is traditionally used in
applications where electrical efficiency and heat
dissipation are of critical importance, such as a
laptop computer. Due to their widespread
adoption in other applications, the cost of
components has decreased, and their
availability has increased, making this an
interesting alternative for driving LED arrays.
A block diagram of a simple switching current
source is shown in Figure 4.9.
Figure 4.10 Resistance-Temperature curve for
PTC resistor.
The PWM module varies the pulse width based
on the input and feedback voltages. The
feedback voltage is proportional to the current
It can be seen that the resistance of such a device
through the LED array, where voltage is
radically increases when the body temperature of
measured directly above a small fixed
the PTC resistor reaches the switching
resistance connected to ground. The filter
temperature. By designing a drive circuit such that
circuitry is used to smooth out the output
the switching temperature occurs at a
voltage of the PWM / transistor switch. With
temperature less than Ta(max), full current derating
minor modifications, this type of circuit can be
is not necessary.
used to drive multiple LED arrays and a variety
of drive circuits.
Consider the case in which the switching
temperature of the PTC resistor is achieved at an
11
ambient temperature of 50 °C at the maximum
input voltage. The forward current at Ta < 50 °C
is 55 mA, and due to the increase in resistance
the forward current at Ta > 50 °C is 30 mA. In
such a case, the maximum junction
temperature will be achieved at 50 °C,
therefore, 50 °C can be used as Ta(max) in the
Figure 4.11 Current control circuit using
temperature compensation.
current derating calculations.
An example of a current control circuit using
temperature compensation is shown in
Figure 4.11.
Appendix 4A
Alternate Junction-to-Ambient Thermal Resistance
Measurement Procedure
Step 1: Pick one LED within the assembly
wires to one cathode lead and to one anode lead
to be used as the DUT. The hottest LED in the
of an LED, which is of the same type as the DUT.
assembly should be chosen, for example an
Next solder the other end of these wires directly
LED in the middle of the assembly and next to
to the PCB in such a way as to have this dummy
a resistor.
LED take the place of the DUT in the circuit.
Step 2: Electrically isolate the DUT from the rest
Step 5: Assemble the modified PCB into the lamp
of the circuit by cutting the appropriate Copper
housing such that the dummy LED and the DUT
traces on the printed circuit board (PCB).
wires are extending outside the lamp.
Step 3: Solder long thin wires onto one cathode
Step 6: Measure the initial Vf of the DUT at a very
lead and one anode lead of the DUT. These
low test current. This test current should be low
wires should be long enough to extend outside
enough such that it causes a minimum amount
the lamp housing once it is reassembled
of heating (1 mA is recommended).
because they will be used to apply the heating
current and to measure the ∆Vf of the DUT.
Step 7: Energize the entire lamp assembly at the
design voltage, and DUT at the design current for
Step 4: Complete the original circuit of the PCB
the individual LEDs for a minimum of 30 minutes.
assembly by attaching a dummy LED onto the
This will allow the lamp assembly to thermally
PCB to take the place of the isolated DUT. This
stabilize.
can be accomplished by soldering long, thin
12
Step 8: Measure the Vf of the DUT at the
Step 11: Calculate the power, P, into the DUT by
heating current (Vf heating).
multiplying the heating/design current by its
Step 9: Turn off all power to the lamp, and
corresponding Vf heating as determined in Step 8.
immediately (≤ 10 ms) remeasure the Vf of
the DUT at the test current selected in 6).
Step 12: Calculate Rθ ja using the values of ∆Tj and
P calculated in Steps 10 and 11. Lumileds can
Step 10: Calculate the ∆Tj of the DUT by
provide the Rθ ja measurements of LED lamp
dividing the ∆ Vf (∆Vf = Vf (Step 6) Vf (Step 9)) by
assemblies as described above as a service to its
the appropriate factor in Table 4.3.
LED customers.
Table 4.3
Ratios of the change in forward voltage vs. the change
in junction temperature for high-brightness led materials
LED Material Type
∆ Vf /∆ Tj ( mV / °C)
AS AlInGap
TS AlInGap
-2.0
-2.0
13
Company Information
Lumileds is a worldclass supplier of Light Emitting Diodes (LEDs) producing
billions of LEDs annually. Lumileds is a fully integrated supplier, producing
core LED material in all three base colors (Red, Green, Blue)
and White. Lumileds has R&D development centers in San Jose,
California and Best, The Netherlands. Production capabilities in
San Jose, California and Malaysia.
Lumileds is pioneering the highflux LED technology and bridging the gap
between solid state LED technology and the lighting world. Lumileds is
absolutely dedicated to bringing the best and brightest LED technology to
enable new applications and markets in the Lighting world.
LUMILEDS
www.luxeon.com
www.lumileds.com
For technical assistance or the
location of your nearest Lumileds
sales office, call:
2002 Lumileds Lighting. All rights reserved. Lumileds Lighting is a joint venture between Agilent Technologies and Philips
Lighting. Luxeon is a trademark of Lumileds Lighting, LLC. Product specifications are subject to change without notice.
Publication No. AB204 (Sept2002)
14
Worldwide:
+1 408-435-6044
US Toll free: 877-298-9455
Europe: +31 499 339 439
Asia: +65 6248 4759
Fax: 408-435-6855
Email us at [email protected]
Lumileds Lighting, LLC
370 West Trimble Road
San Jose, CA 95131