Handling Note SHARP COB ZENIGATA LED SERIES

Transcription

1 Handling Note SHARP COB ZENIGATA LED SERIES

2 This note applies to Sharp's ZENIGATA series of LEDs. Petit ZENIGATA LED Mini ZENIGATA LED Mega ZENIGATA LED Tiger ZENIGATA LED

3 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:

4 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.

5 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

6 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) ST0903 (Silanex Technology) 30 W/m K 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. 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.

7 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.

8 Handling Note 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.

9 Handling Note Contents in this technical document be changed without any notice due to the product modification. 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 8

10 Handling Note White Resin area Coloured resin area (light emitting area) 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.

11 Handling Note 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. 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 M mm 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.

12 Solder iron Solder iron Solder iron does not touch the resin. 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.

13 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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15 Handling Note <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]

16 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.

17 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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