ZENIGATA LED
Dec 1, 2015
Handling Note
SHARP COB ZENIGATA LED SERIES
INDEX
① Products
② Storage Conditions
③ Thermal Considerations
④ LED Handling
⑤ Operating Temperature
⑥ Solder Connection
⑦ Operating Environment
⑧ Driver Design
⑨ Other Considerations
⑩ Safety Precautions
Contents in this technical document be changed without any notice due to the product modification.
Development DepartmentⅡ
Lighting Device Division
Electronic Components And Devices Group
http://www.sharp-world.com/products/device/
SHARP CORPORATION
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① Products
This note applies to Sharp's ZENIGATA series of LEDs.
・Petit ZENIGATA LED　・Mini ZENIGATA LED　・Mega ZENIGATA LED
・Tiger ZENIGATA LED
・Petit ZENIGATA（Size：12×mm）
・Mini ZENIAGTA（Size：12×15mm）
・Mega ZENIGATA（Size：20×24mm）
・Tiger ZENIGATA（Size：20×24mm）
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②　Storage Conditions
LED device are kept in trays which are piled on top of one another. These trays are packed
in moisture-proof bag.
Please use the LEDs as early as possible after opening the moisture-proof bag.
Please keep unused LEDs in the bag with some moisture absorbent material(silica gel) or
in a desiccator with controlled temperature and humidity. in this case, refer to the storage
conditions mentioned in the specification, and store accordingly.
The solder pad material of standard ZENIGATA LEDs is made of silver.
After opening the aluminum packing bag, if the LEDs are left open for long time, it is
possible that the solder pad will oxidize or react with corrosive gases (like Cl2,H2S,NH3,
SO2,NOx).
This could lead to difficulties during the soldering process and potentially cause damage
to the pad.
Therefore, please refrain from keeping the LEDs open for long time, and do not store the
LEDs in an environment that contains above stated corrosive gases.
The following images indicate the change in visual appearance of the pad after oxidation
damage:
Normal appearance
Oxidation damaged
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③　Thermal Considerations
When using an LED device, use highly thermal conductive material or adhesive sheet and mount
on appropriate heat sink.
If forward current ( IF ) is applied to LED device alone, without fixing the device to heat sink,
temperature of the device will increase beyond the maximum allowed values, and may lead
to smoke emission, and other LED device defects.
If the device is not mounted properly on the heat sink, heat dissipation does not occur propely,
potentially leading to over-heating, which may result in substrate cracking, and failure of the
LED.
Therefore,careful study should be done when designing a thermal solution before use.
3-1 Heat sink surface
The surface of heat sink on which the LED device will be mounted must be flat and free from
scratches and debris.
If the surface of the heat sink is not flat ( e.g.convex,concave), heat dissipation does not
occur properly,potentially increasing the case temperature as well as junction temperature,
and ultimately leading to failure of LED device.
Any scratches on the surface of heat sink could decrease the thermal conductivity.
Therefore please check the surface of heat sink before use.
Any deformation or damage to the heat sink surface will increase thermal resistance and
decrease heat dissipation, potentially leading to over-heating and ultimately failure of the LED.
If the surface of the heat sink is not flat(e.g.convex) it may induce cracking of the ceramic
substrate which will result in failure of the device.
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3-2 Mounting on Heat sink
When mounting LED device on heat sink, use highly thermal conductive adhesive material
or adhesive sheet.
In case of holder also,please mount in the similar way.
In either case, use effective heat dissipation material in between heat sink and ceramic
substrate as shown in below figure, and also take careful note of the reliability of heat
dissipation and adhesion.
Make sure the device will not detach from the heat sink even when used for long time, and
the case temperature does not exceed maximum rating value.
Increase in the temperature of LED device beyond the maximum allowed values may lead
to device deterioration, lead wire detachments, smoke emission, and other LED device defects.
LED device
Adhesive Material
Heat Sink
Closely contact
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3-3 Thermal adhesive selection
If opting to use a thermal adhesive to attach the LED to heat sink, please select a product
with high thermal conductivity.
Reliability tests should be performed before entering mass production,especially for high
wattage LEDs such as the Mega-ZENIGATA series.
Example products with suitable thermal characteristics:(data provided by adhesive suppliers)
TIA600R
( Performance Materials)
6 W/m・K
To ensure good heat dissipation, check that the mating surface of the LED device and heat
sink are clean without any foreign materials on the surface, and that the thickness of the
adhesive is controlled to be less than 100um.
The adhesive should be spread uniformly across the entire back surface of the LED ceramic
substrate. It is recommended that adhesive material is pushed out from every side of the
substrate by pressing ZENIGATA LED on the heat sink during the mounting process.
1）Adhesive uniformity
If adhesive is not spread uniformly across the back side of the ceramic substrate, LED may be
damaged by local heat build-up, even if Tc is controlled with in specification.
In such cases, local variations in thermal expansion may cause the ceramic substrate to crack.
Resin degradation at non-adhesive area
I-
I+
Pink - adhesive
white - non-adhesive
2）Thermal grease selection
If opting to use a thermal grease to make contact between LED and heat sink, please select a
product with high thermal conductivity. Considerations on thickness and uniformity are the
same as for thermal adhesives. Please check lifetime performance of heat dissipation as this
may be affected by solidification or other forms of degradation after long periods of use.
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3) Thermal sheet selection
Please use highly adhesive thermal sheet to make contact between LED device and heat sink.
For better adhesive performance, thermal sheet which is soft is recommended to use.
Please use the thermal sheet which has thermal conductivity more than 3 W/m・K
Example:
FSL-B (DENKI KAGAKU KOGYO)
(data provided by the supplier)
3W/m・K
If the thermal sheet which doesnʼt have good adhesive property is used, gap may arise between
LED device and thermal interface material, which may affect the heat dissipation of the device.
If the LED device detaches from the thermal sheet, LED may get damage due to overheat.
Therefore fix the LED device using holder.
Please select a product which has good adhesive performance on both sides, and
thickness<0.3mm.
Moreover, the long-time reliability of the thermal sheet on the lighting fixtures should also be
studied carefully before use.
4) Reliability of adhesive, grease, thermal sheets
The performance of the adhesive, grease, thermal sheets may change due to the effect of
heat and light when used for long time.
The long-time reliability of thermal interface materials should be studied very carefully before
mass production.
ZENIGATA LEDs do exhibit some light leakage through the ceramic substrate.
Please carefully study the effect of heat and light on these materials.
Please take note of the effect of materials such as low molecular weight silicone compounds
that may emit from the grease or other materials used between heat sink and the LED device.
5) Effect of heat sink and other heat dissipation materials on LED deviceʼs light output
The light reflectivity efficiency of heat sink and other thermal interface materials may affect
the light-output of LED device.
Therefore it is very important to verify the following factors while designing thermal solutions:
1. Whether the initial reflectivity efficiency values of the above mentioned materials are stable
or not.
2. Whether any color change that occurs due to long term use has an effect on light output.
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3-4 COB Holder usage
When using a holder to fix the LED device with heat sink, please use a thermal interface
material (E.g.grease or thermal sheet) on the back side of the device.
LEDs with solder-less connection pad material are not compatible with soldering processes.
In case a solder-less electrical connector will be used, a different pad material is available
and should be considered depending on the application.
We recommend that electrical contact between LED and holder is made using spring
connectors to regulate the pressure applied to the LED.
If excessive pressure is applied it may result in damage to the LED contact pad or even
cracking of the ceramic substrate.
The performance of the holder may change due to the effect of heat and light when used
for long time.
The long-time reliability of holders should be studied very carefully before use.
3-5 Positioning of the LED device
When searching for the fixing-point for LED device or for the holder fixing design,please
avoid using the corners for position fixing, as there may be salient areas on the corners
(edges) of LED device.
Any excessive or uneven stress on the ceramic substrate could break the substrate.
Please design such that, proper/uniform stress is applied on the substrate, when fixing the
LED device using a holder.
In case of using an impact driver to fasten screw to fix the holder and the LED device,
make sure that the vibration created by the driver does not have any effect on the quality
issues of the LED device.
When fixing the LED device with a holder, please take note of any excessive or uneven stress
is applied when pressing the substrate with holder.
Due to this reason,gap may arise between LED device and thermal interface material,which
may affect the heat dissipation of the device.
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④　LED Handling
When mounting ZENIGATA LEDs, please handle by side part of substrate or the specified
area shown below.
Do not touch the colored resin area of the LED or the white dam ring that surrounds it,
as there are wire connections underneath. Additional components(holder, lens) should
be designed to avoid this area.
Holding section
・TIGER-ZENI, MEGA-ZENIGATA, MINI-ZENIGATA, PETIT-ZENIGATA
> Use anti static gloves or tweezers that are not sharp, and handle at the specified handling area.
> Do not handle at the solder pads > Do not handle on the resin area (including white resin)
> Do not handle with bare hands
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Coloured resin area
(light emitting area)
White Resin area
Electrodes
(solder pads)
※There are wire connections beneath white resin area and light
emitting area. Any external pressure on this area could bend or
cut-off the wires, which may result in device failure.
If any external pressure is applied on the resin area, damage may occur to the wires
underneath the resin as shown in below figure.
(X-ray inspection)
Wire
deformation
Wire cut
Wire cut
Wire
deformation
It is recommended to avoid using pointed tools for handling ZENIGATA LEDs, as they
may damage the resin area on the LED device.
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⑤ Operating Temperature
The temperature of LED devices should be maintained as per the Tc (case temperature)
measured at the measuring point mentioned in the specification, and always use it inside
the range of de-rating curve.
While measuring Tc, please take care of the following things:
● The LED device mounting surface should be flat/plain surface.
● The substrate surface temperature should be uniform.
● Refer to section6 for regulations related to soldering temperature and reliabilities.
The de-rating curve in the specification does not guarantee solder connection.
⑥ Solder Connection
In case of solder connection, use the LED device that is designed with soldered
electrical connections.
An example for solder connection:
Soldering Duration: 3 seconds (Keep the device on the material that has less
conductivity while soldering)
Soldering iron: HAKKO FX-591(Main Body), FM-2028(solder iron), T12-B2(solder iron tip)
Soldering iron tip temperature: 380 degrees
Soldering Material: Wire solder Senju Metal Industry M705 0.65mm
Temperature controlled soldering iron is recommended to use. However, solder may not
melt properly or contaminate electrodes, depending on the material properties of soldering
iron, solder, and also heat dissipation performance of the material on which soldering is done.
Therefore, please check the conditions carefully before soldering.
If soldering is done after the LED is mounted on heat sink, it may be difficult to reach a high
enough temperature to melt the solder. In that case, increase the temperature of the soldering
tip to ensure a high quality soldered connection.
If pre-soldering is possible before mounting on heat sink, it is recommended to do pre-soldering
on electrodes of the LED device.
The ceramic substrate has a very high thermal conductivity. Due to this reason, when soldering,
do not keep the LED device on a high thermal conductive object, as this may prevent the solder
pad reaching a sufficiently high temperature. We recommend using hotplate with preset
temperature. (preset condition:100 deg. to 150 deg: under 60 seconds)
A soldering material with good reliability at elevated temperatures is essential because the LED
will go through many temperature cycles during its lifetime. Lower quality materials may
experience cracking or creep. The soldering iron should not touch the resin(circular) area of
the LED. To avoid damage to this area, you are advised to do the soldering process such that
the soldering tool approaches the pad from the outside of the LED, as depicted in the diagram
below.
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Solder iron
Solder iron does not touch the resin.
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Solder iron
Solder iron may touch the resin.
※LEDs with Solder connection pad material are not compatible for solder-less connection.
Others:
・Please do not attempt to re-solder a detached wire as this may result in a connection with
reduced strength.
・Soldering should be performed on a stable stand. Avoid soldering ZENIGATA LED devices
on vibrating or moving objects.
・Please ensure that the entire pad is covered in solder.
・Please prevent flux and other soldering particles from touching the resin.
・Flow/reflow soldering techniques are not applicable for ZENIGATA LED devices.
・Please refrain from using soldering paste.
・Please arrange wire to not cause mechanical stress to the solder pad.
・Secure the solder wettability on whole solder pad and leads.
・In case of using at high temperatures, use the soldering material that can withstand
creep failures.
・LED devices that are designed for soldered connections, should not be connected with
other solder-less electrical connectors. Solder-less connections are prone to oxidation
and sulphurization, which could cause defects in electrical connectivity.
In case a solder-less electrical connector will be used, a different pad material is available
and should be considered depending on the application.
・LEDs with solder-less connection pad material are not compatible with soldering processes.
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⑦ Operating Environment
This product is not designed for use under any of following conditions:
● A high moisture environment.
● In briny air or corrosive gas (Cl, H2S, NH3, SO2, NOx, etc.)
● Under direct sunlight (due to photo voltaic effect).
● Outdoor exposure.
● Dust.
● Water, oil, medical fluid or organic solvent.
Careful attention should be made to the nature of compounds out gassed by materials and
components within an LED lighting fixture - specifically their compatibility with the LED device.
If such compounds are prone to photo-degradation the degradation the degradation products
must also be considered.
The closed nature of many lighting fixtures means that such compounds can become trapped,
potentially resulting in high concentrations close to the LED.
Some compounds known to be detrimental to the LED include silicones, volatile organic
solvents(VOCs), strong acids and alcohols.
If a customer intends to use a ZENIGATA LED under any of these conditions they will need
to confirm performance and reliability for themselves.
The chemicals listed in below table have potential risks to react with chip, silicone resin or
other materials in LED device and may cause quality problems for LED device.
Therefore, the materials which contain or generate these chemicals should not be used in
the vicinity of LED device.
If they are necessary to use around LED device, please evaluate and check the effect of these
chemicals on LED device performance and reliability
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<Effect of LED light on surrounding materials>
The light from LED could change the color or shape of surrounding materials.
Please check the reliability of these materials with LED device before use.
<Under sunlight>
When an LED is illuminated under sunlight the photoelectric effect can induce a reverse
voltage and damage the device.
Please prevent direct and indirect illumination of ZENIGATA LEDs
by sunlight
The photo-voltaic effect is dependent on the properties of the light illuminating a chip and the
characteristics of the chip itself. ZENIGATA LEDs are connected in series, meaning the LED
chip with the lowest electromotive force(E.M.F) will be affected by the reverse voltage of all
LED chips in the series.
Current [nA]
I-V Behavior
Light intensity
Voltage[V]
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⑧ Driver Design
・LED chips are connected in both series and parallel in ZENIGATA LED. With increase in
temperature, the voltage of LEDs will decline. Therefore, do not use constant voltage
power supplies as current may increase beyond safe limits. It is recommended to use
the constant current power supply (Avoid using Constant Voltage Power Supply).
・When multiple ZENIGATA LEDs are used, connect the LED devices in series only.
If the ZENIGATA LEDs are connected in parallel, there is a danger that high currents
may pass through those LEDs with the lowest voltages.
Therefore avoid connecting ZENIGATA LEDs in parallel.
＋
Power Source
−
Do not connect the ZENIGATA LEDs in parallel
・Please use a driver with built-in surge protection.
・Do not apply reverse polarity to the LED. Furthermore, when the LED is not in operation
avoid applying any voltage(forward or reverse voltage).
・Design the driver to avoid spikes in current as inrush currents may cause gold contact
wires to melt.
・If the LED device is switched(ON/OFF) excessively, the resin surface on the device will
expand and shrink several times due to the temperature difference.
This could damage the wires in between LED dies, and may lead to device failure.
Therefore, before using the LED device, please do the tests considering usage environment.
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⑨ Other Considerations
・To protect from electrostatic damage, please use an anti static wrist band when handling.
・Do not use tools and processes which create a large amount of vibration as this may damage
the LED.
・The light and heat released from LED device may change the properties of materials of LED
lighting fixtures(LENS, reflectors, holders) that are used around the LED.
Therefore, the material properties of fixtures should be considered carefully before designing.
・If the LED lighting fixtures are designed in such a way, that the light from the LED device is
concentrated narrowly, or when high power LED devices like MEGA ZENIGATA are used,
it is important to check the light energy from the LEDs do not cause any abnormal heat
generation or smoke emission due to light observation or color degradation of the fixtures.
・Avoid cleaning, since silicone resin may be eroded by cleaning.
⑩ Safety Precautions
・Looking directly at LEDs for a long time may result in hurting your eyes.
・In the event of excess current(over ratings) being supplied to the device, hazardous
Phenomena including abnormal heat generation, smoke emission, or fire can be caused.
Take appropriate measures to avoid excess current and voltage.
・Please confirm the safety standards or regulations of application devices.
・Please be careful with substrate edges, which may injure your hands.
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