Instruction Mannual (COB LED Package) CONTENTS 1. Product Description P.2 2. Handling COB LED package P.3 3. Soldering Process P.6 4. Mechanical Assembly P.7 5. Thermal Design P.10 6. Electrical Connection P.11 7. Chemical Incompatibility P.14 8. Solutions P.15 CITIZEN ELECTRONICS CO., LTD. 1-23-1, Kamikurechi, Fujiyoshida-shi, Yamanashi, 403-0001, Japan 䚷Tel. +81-555-23-4121 䚷http://ce.citizen.co.jp Copyright © 2010 CITIZEN ELECTRONICS CO., LTD. All Rights reserved. Ref.CE-P2468 03/13 1, Product Description 1-1, Introduction Citizen Electronics has been seeking the highest level of brightness and efficacy in the LED package industry. In addition, we have endeavored to work out technical solutions for many years. Through our advanced manufacturing technique and packaging technology, Citizen Electronics COB LED package series product will bring you a lighting space full of delight and beauty. 1-2, Citizen Electronics COB LED Package series delivers “A world’s best Lumen performance and efficacy”, “High reliability and long life based on proven data by actual measurement”, “Extensive product lineup”. This application note provides recommendations for handling, soldering, mechanical assembly, thermal design, electrical connection, chemical Incompatibility, solutions. Product Description of COB LED Package The mechanical feature of COB LED package series shows at Figure1. COB LED package has Anode (positive electrode) and Cathode (negative electrode) on the aluminum board. The resin area is composed of mounting LED dices on the aluminum board and enclosing them by silicone resin including fluorescent substance. Besides it is possible for COB LED Package to be assembled into the heatsink directly, though it is not possible for SMD type of LED package. Therefore it is not necessary to use the mounting flow and printed circuit board. COB LED Package has high thermal dissipation performance by mounting LED dies directly on the aluminum board. COB LED package series makes it possible to design the LED light fixture downsized. Example application for using the COB LED package fixture is street light, down light, spot light, bulb. ■Figure1 COB LED package Anode Resin area Aluminum board Cathode (TC measurement point) 2 Copyright © 2010 CITIZEN ELECTRONICS CO., LTD. All Rights reserved. CITIZEN ELECTRONICS CO., LTD. 1-23-1, Kamikurechi, Fujiyoshida-shi, Yamanashi, 403-0001, Japan Tel. +81-555-23-4121 http://ce.citizen.co.jp Ref.CE-P2468 03/13 2 , Handling COB LED Package 2-1, Precaution for taking out from the tray COB LED package series are supplied by packing tray which made from electrically conductive polystyrene. (Figure2) Please be aware to hold edge part of the tray and transport. (Figure3) If the force applied to the resin area inside of the tray, the bottom surface of the tray may press the resin area and have negative impact into the function, performance and reliability of these products. ■Figure3 The way for Transporting the tray Correct ■Figure2 Appearance of the packing tray Wrong NG The packing tray is designed stackable without contact and press this product, in the case trays are stacked on the same direction by matching the reference surface. (Figure8) Please be aware to open the tray on a flat surface and treat the LED package under the clean environment avoiding dust and particles, which may adhere to the resin area of the LED package. In the case the reference surface is set on left bottom side, Don’t push the tray the direction of LED package(cathode and Anode electrical pad) is located like Figure4. It is strongly recommended to use antistatic gloves for taking out from the packing tray, and not to handle by naked finger. (Figure5) In addition, please avoid the sharp objects like tweezers to catch and hold of LED packages, because they may affect the wire inside of the resin area to be disconnection, and it may affect the light break down. ■Figure4 The package part of the packing tray ■Figure5 The recommended way to hand out the production Anode Cathode Reference surface 3 Copyright © 2010 CITIZEN ELECTRONICS CO., LTD. All Rights reserved. CITIZEN ELECTRONICS CO., LTD. 1-23-1, Kamikurechi, Fujiyoshida-shi, Yamanashi, 403-0001, Japan Tel. +81-555-23-4121 http://ce.citizen.co.jp Ref.CE-P2468 03/13 2-2, Precaution for holding Please be aware to avoid putting mechanical stress on the LED package especially the resin area. It may affect LED light break down. Please handle the LED package with care. It is recommended to wear antistatic gloves to prevent dirt or other contaminants from adhering to the resin area. They may affect negative impact to the optical performance of LED package. Please ensure that any objects don’t attach and push the resin area. Please do not use sharp objects like tweezers to catch and hold of LED packages. The wire inside of the resin part may be disconnection and it may affect the light break down. The recommended way to handle shows at Figure6. ■Figure6 Recommended way to handle Correct Strongly recommended to use antistatic gloves Wrong NG NG Do not use tweezers Do not touch the resin area NG Do not touch with naked finger NG Do not touch the resin area 4 Copyright © 2010 CITIZEN ELECTRONICS CO., LTD. All Rights reserved. CITIZEN ELECTRONICS CO., LTD. 1-23-1, Kamikurechi, Fujiyoshida-shi, Yamanashi, 403-0001, Japan Tel. +81-555-23-4121 http://ce.citizen.co.jp Ref.CE-P2468 03/13 2-3, Precaution for handling i) The resin part is composed of the light emitting area and white dam erea. Please avoid the sharp objections (Figure7) to press the resin or stress, rub, attach and contact with. They might be affect the function, performance and reliability of this product to attack negatively impact. ■Figure7 Prohibitions of press the resin area Wrong NG Screw Driver NG NG Pen NG Finger Tweezer NG Screw ii) Please make sure the resin area should not be attached and contact by any other parts during assembly process. (Figure8) ■Figure8 Prohibition of contact between the resin area and other parts Correct Wrong NG Assembly part contact the emitting surface. iii) Please be aware not stack this product, It might occur damage into the LED package such as peeled, clacked, wire disconnected. (Figure9) ■Figure9 Prohibition of stacking LED packages Wrong NG 5 Copyright © 2010 CITIZEN ELECTRONICS CO., LTD. All Rights reserved. CITIZEN ELECTRONICS CO., LTD. 1-23-1, Kamikurechi, Fujiyoshida-shi, Yamanashi, 403-0001, Japan Tel. +81-555-23-4121 http://ce.citizen.co.jp Ref.CE-P2468 03/13 3 , Soldering Process 3-1, Recommended Soldering process 3-2-2, Position of Soldering Lead Wire on the soldering pad This product is not adaptable to reflow process. The conditions below are recommended for soldering. Please refer the positioning between the lead wire and the soldering pad at pictures below.(Figure10) Recommended soldering condition Out put of soldering iron : ■Figure10 The way for soldering lead wire Soldering bit temperature shall be 350䉝 or less Heating time : 3.5 seconds or less per land Correct Not over the conductive part of wire from soldering pad. No external force shall be applied to the resin area. In addition, please ensure that the soldering bit has no contact with the resin area. Next process of soldering should be carried out after the product has returned to ambient temperature. 3-2, Recommended Soldering Appearance 3-2-1, Appearance Condition of Soldering Lead Wire Make sure following the items. 1, The soldering fillet is formed. 2, The core part is solderad well. 3, The solder has shiny appearance. 4, There is not the protuberance or extreme raised on soldering. 5, The lead wire don’t floot up from the pad. 6, The solder covers well around outside and the side surface of lead wire. 7, There is not attach soldering (e.g. soldering ball, soldering flux) at out of the designated pad for soldering extremely. The solder lands on the 2/3 space of pad of LED package 8, board. The conductive part of lead wire doesn’t land on the 9, outside of the soldering pad. The height of the conductive part of lead wire and the 10, soldering don’t put over the height of the insulated plasted part. Wrong NG The conductive part of wire is over from soldering pad. NG NG 6 Over at front edge Over at bottom edge Copyright © 2010 CITIZEN ELECTRONICS CO., LTD. All Rights reserved. CITIZEN ELECTRONICS CO., LTD. 1-23-1, Kamikurechi, Fujiyoshida-shi, Yamanashi, 403-0001, Japan Tel. +81-555-23-4121 http://ce.citizen.co.jp Ref.CE-P2468 03/13 4, Mechanical Assembly 4-1-1, Reference Assembly1: M3Screw, Thermal conductivity two sided adhesive sheet Regarding assembling COB LED package CLL020, CLL022, CLL030, CLL032, CLL040, CLL042,CLL050, CLL052, CL-L100 series it is possible to fix on heatsink directly with M3 screw by using TI M (thermal interface material). A reference assembly of a lighting system is showing at Figure11. It may be applied to mounting screws is 0.6 Newtoncentimeters. Please follow the position information of Figure12 for fixture with M3 screws. It is strongly recommend to tightening screws on heatsink by second time, at first fix each side of screw temporarily, and tightening them finally in order not to put over power of mechanical stress into LED package. In order to reduce the thermal resistance at assembly, please use TIM on whole contact surface of the product. In the case of using thermal grease as the TIM, it is recommend to apply uniformly on the contact surface of the product. For using thermal sheet as the TIM, it is recommend to make sure that the product is not strained by stress when the screws are tightened for assembly. In addition, regarding assembling COB LED package CLL010, CLL012, please use the thermal conductivity two-sided adhesive sheet to fix on heatsink. As a reference information, we offer the information of TC-20SAS (Shin-Etsu Chemical Co., Ltd.). Dielectric voltage withstand test has been conducted on this product to see any failure after applying voltage between active pads and aluminum section of the product, and to pass at least 500V. Please confirm your final product for electrical safety of your product. ■Figure11 Reference assembly as fixing with M3 screws M3 screw Spring washer (䍺Φ6mm) Flat washer (䍺Φ6mm) TIM Heatsink ■Figure12 Recommended screw location and pitch 46.5 12.8 22.8 18.3 12.8 32.0 18.3 22.8 32.0 CLL020 CLL022 CLL030 CLL032 CLL040 CLL042 CLL050 CLL052 7 CL-L100series Copyright © 2010 CITIZEN ELECTRONICS CO., LTD. All Rights reserved. CITIZEN ELECTRONICS CO., LTD. 1-23-1, Kamikurechi, Fujiyoshida-shi, Yamanashi, 403-0001, Japan Tel. +81-555-23-4121 http://ce.citizen.co.jp Ref.CE-P2468 03/13 4-1-2, Reference Assembly2 : Connector A reference assembly of a lighting system using COB LED package shows in Figure13,14. Connector, COB LED package, TIM, Heatsink are assembled like Figure13. Please use TIM for better condition of heat dissipation. There is information about the recommended connector on “8, Solutions” of this application note. Please follow the specification of each maker’s connector. ■Figure13 Reference Assembly ■Figure14 Assembly image Connector COB LED Package TIM(Thermal Interface Materials) Heatsink 8 Copyright © 2010 CITIZEN ELECTRONICS CO., LTD. All Rights reserved. CITIZEN ELECTRONICS CO., LTD. 1-23-1, Kamikurechi, Fujiyoshida-shi, Yamanashi, 403-0001, Japan Tel. +81-555-23-4121 http://ce.citizen.co.jp Ref.CE-P2468 03/13 4-2, Precaution for assembly i) Please be aware to contact the resin area of the COB LED package during assembly. Please do not use sharp objects especially finger, screw, screw driver, pen to catch and hold of LED package. The wire inside of the resin area may be disconnection and affect the light breakdown. (Figure15) ii) In the case of assembling , please be aware to use the correct way which is followed by the specification of each products. Besides please do not fix the product by over torque and put huge stress into the product. (Figure16) ■Figure16 Prohibit huge stress and over torque ■Figure15 Prohibit using sharp objects Wrong Wrong NG Finger nail NG NG Over torque Screw iii) Please assemble the correct way and not to push the resin area with any other parts during assembling the product. (Figure17) ■Figure17 Prohibit incorrect assembly Wrong NG Screw driver NG Pen NG 9 Copyright © 2010 CITIZEN ELECTRONICS CO., LTD. All Rights reserved. CITIZEN ELECTRONICS CO., LTD. 1-23-1, Kamikurechi, Fujiyoshida-shi, Yamanashi, 403-0001, Japan Tel. +81-555-23-4121 http://ce.citizen.co.jp Ref.CE-P2468 03/13 5, Thermal Design 5-1, Significance of the heat dissipation structure An LED package radiates light and heat according to the input power. However, the surface area of an LED package is quite small, and the package itself is expected to release little heat into the atmosphere. An external radiator such as a heatsink is thus required. The heat dissipation structure up to the connection portion of the external radiator uses mainly heat conduction. Regarding LED packages, to control the junction temperature of the LED dice Tj is important. The Tj must be kept from exceeding the absolute maximum rating in the specifications under any conditions. As direct measurement of the junction temperature of a LED dice inside a package is difficult, the temperature of a particular part on the 5-2, external package (the case temperature) Tc [ 䉝 ] is normally measured. Tj [ 䉝 ] is calculated using the thermal resistance between the junction and the case Rj-c [ 䉝 / W], and the input power Pi [W] considered as the emitted heat amount. The heat generated at the LED dice can be conducted to the external radiator efficiently because the package structure for the COB LED package minimizes the thermal resistance Rj-c. This document describes the detailed heat dissipation structure of the COB LED package and provides data necessary for thermal design of the lighting apparatus to maximize performance. Package structure and thermal resistance The cross-sectional structure example, where the COB LED package is connected to an external heatsink, is shown in Figure18.The package has a laminated structure of an aluminum substrate, insulating layers and conductive cooper foil pad. A distinctive point is that the LED dice is mounted directly on the well conductive aluminum substrate not on the insulating layer, which has low thermal conductivity. Thus, the heat generated at the LED dice can be efficiently conducted to the outside of the package. The aluminum substrate side of the package outer shell is thermally connected to the heatsink via TIM. As described above, the heat generated in the junction section of the LED dice is transferred mainly to the heatsink using heat conduction, through the LED dice to the adhesive for diemounting to the aluminum substrate to the TIM. The thermal resistance between the junction section of the LED ■Figure18 COB LED package Cross-Section diagram LED die TJ dice and the aluminum substrate side of the package outer shell is Rj-c, and the specific thermal resistance value of the package. Therefore, the following formula is used: Tj = Rj-c 䞉 Pi + Tc In addition, the thermal resistance of the TIM outside the package is R-TIM [ 䉝 / W], the thermal resistance with the heatsink is Rh [ 䉝 / W], and the ambient temperature is Ta [䉝]. Figure19 indicates the equivalent thermal resistance along the cross-sectional diagram in Figure18. As indicated, the thermal resistances Rj-c, R-TIM, and Rh are connected in series between the junction ■Figure19 temperature Tj and the Thermal Resistance Connection ambient temperature Ta. The thermal resistances outside the Tj Tj package R-TIM and Rh can be integrated into the thermal Rj-c Rj-c resistance Rc-a at this point. Tc Tc Thus, the following formula is R-TIM Rc-a also used: Tc Aluminum TIM Heatsink Rj-c R-TIM Tj = ( Rj-c + Rc-a ) 䞉 Pi + Ta Rh Rh Ta Ta Ta 10 Copyright © 2010 CITIZEN ELECTRONICS CO., LTD. All Rights reserved. CITIZEN ELECTRONICS CO., LTD. 1-23-1, Kamikurechi, Fujiyoshida-shi, Yamanashi, 403-0001, Japan Tel. +81-555-23-4121 http://ce.citizen.co.jp Ref.CE-P2468 03/13 6, Electrical Connection 6-1, Introduction Prior to driving an LED package, which is a kind of semiconductor, it is necessary to thoroughly comprehend its characteristics because it has various elements. For example, the forward current ‘If’ varies widely with fluctuation in the forward voltage ‘Vf’. In the case of Figure20, a 10% rise in Vf results in an increase of If by more than 40% under constant temperature conditions. The fluctuations in If have a significant influence on light emission and heat generation of LED packages. Especially, strict control of If is required for high-power LED packages used for lighting because they are driven by large current. In addition, the measures taken against heat release by an LED package are a crucial factor as Vf varies with temperature. When driving our LED packages, please be sure to read the relevant specifications and application notes and take appropriate measures according to their characteristics. 6-2, ■Figure20 Vf-If characteristic (%) 160 Relat ive If cha nge 140 120 100 80 60 40 80 100 90 120 110 Relat ive Vf cha nge (%) Constant current drive system (recommended) The system that continues to supply a certain current to an LED package even under the conditions that Vf varies with heat generation or other factors is said to be a ‘constant current drive system’. This system allows relatively stable driving of LED packages even under changing environmental conditions or other parameters. In general, an LED package has a tendency for Vf, which applies a certain current to an LED package, to decrease as the temperature increases. (Figure21) Citizen Electronics recommends the constant current drive system to ensure stable light emitting output and reliability. ■Figure21 Tc-Vf characteristic Relat ive Vf cha nge (%) 110 105 100 95 90 0 20 40 60 Case temper at u re Tc 11 80 100 (䉝) Copyright © 2010 CITIZEN ELECTRONICS CO., LTD. All Rights reserved. CITIZEN ELECTRONICS CO., LTD. 1-23-1, Kamikurechi, Fujiyoshida-shi, Yamanashi, 403-0001, Japan Tel. +81-555-23-4121 http://ce.citizen.co.jp Ref.CE-P2468 03/13 6-3, 6-4, Constant voltage drive system Whereas the constant current drive system continues to supply a certain current to an LED package, the system that continues supplying a certain voltage to an LED package is said to be a ‘constant voltage drive system’. As described above, an LED package has a tendency for Vf, which applies a certain current to an LED package, to decrease as the temperature increases. In the case of Figure18, when the case temperature Tc is 90°C, the same amount of current is achieved by approximately 5% lower Vf than that of the condition in which Tc is 25°C. From another perspective, when an LED package is operated with a certain voltage, the more the temperature increases, the larger the current that flows through the LED package. In cases of driving with a constant voltage, as shown in Figure22, temperature changes lead to changes in Vf and current as the temperature of an LED package is unstable due to variance in environmental temperature or other factors. Accordingly, the brightness of an LED package can be unstable as it depends on current. Thus, when driving with a constant voltage is employed, an appropriate measure such as the connection of current control resistance needs to be implemented based on an assumption of the temperature in actual use. ■Figure22 Precautions for inrush current When an LED package is connected to capacitive load such as a capacitor, instantaneous inrush current may occur during on/off operations. For instance, this includes the case where the second side of energized power circuit is turned on/off. Citizen Electronics recommends usage that avoids the occurrence of inrush current as much as possible. In cases where the occurrence of inrush current is unavoidable, please be sure to take measures to prevent exceeding the absolute maximum rating of the relevant LED package. 6-5, Connection between multiple LED packages When connecting multiple identical LED package products, the series connection makes current flowing through LED packages uniform. Citizen Electronics recommends series connection to ensure stable lightemitting output and reliability. On the other hand, a parallel connection should be considered for Vf variation between LED packages. Some measures, such as the appropriate current regulation resistor being connected to each LED package in series based on the temperature conditions in actual use, are required to apply even current to each LED package with different Vf characteristics. Instability due to driving with constant current Temperature change of LED package Vf change Current change Brightness change 12 Copyright © 2010 CITIZEN ELECTRONICS CO., LTD. All Rights reserved. CITIZEN ELECTRONICS CO., LTD. 1-23-1, Kamikurechi, Fujiyoshida-shi, Yamanashi, 403-0001, Japan Tel. +81-555-23-4121 http://ce.citizen.co.jp Ref.CE-P2468 03/13 6-6, A parallel connection of LED packages There is the way below for using n LED packages as the parallel connection. 6-6-1, The case of using constant current drive system The way to prepare the Constant current circuit for each LED package line.(Figure23) ■Figure23 ■ If1,Ifn LP n LP1 If 1 volt age sou rce If n Current for each LED package ■ CC1,CCn Constant Current drive V CC1 ■ LP1,LPn CCn LED package 6-6-2, The case of using current-limiting resistor The equivalence circuit in the case setting current-limiting resistor for each LED package line.(Figure24) ■Figure24 ■ If1, LP n LP1 constantvoltage source If 1 Current for each LED package ■ R1, If n Ifn Rn Current-limiting resistor V Rn R1 13 ■ LP1, LPn LED package Copyright © 2010 CITIZEN ELECTRONICS CO., LTD. All Rights reserved. CITIZEN ELECTRONICS CO., LTD. 1-23-1, Kamikurechi, Fujiyoshida-shi, Yamanashi, 403-0001, Japan Tel. +81-555-23-4121 http://ce.citizen.co.jp Ref.CE-P2468 03/13 7, Chemical Incompatibility The LED pakage contains a silicone to protect the LED dies and the silicone is gas permeable. Some VOCs(volatile organic compound) and chemicals will cause discoloration, surface damage, crack, erosion. Table1 is showing the list of harmful materials will damage the silicone. Please do not use them together with the LED package. If it is necessary to use them together, please consider and test them before use. ■Table1 List of harmful materials that will damage the silicone. ~ Chemical Name ~ hydrochloric acid sulfuric acid nitric acid acetic acid sodium hydroxide potassium hydroxide ammonia MEK (Methyl Ethyl Ketone) MIBK (Methyl Isobutyl Ketone) Toluene Xylene Benzene Gasoline Mineral spirits dichloromethane tetrachloromethane Castor oil lard linseed oil petroleum silicone oil halogenated hydrocarbons (containing F, Cl, Br elements) rosin flux 14 Copyright © 2010 CITIZEN ELECTRONICS CO., LTD. All Rights reserved. CITIZEN ELECTRONICS CO., LTD. 1-23-1, Kamikurechi, Fujiyoshida-shi, Yamanashi, 403-0001, Japan Tel. +81-555-23-4121 http://ce.citizen.co.jp Ref.CE-P2468 03/13 8, Solutions The short list below shows some commercially available design resources. Citizen Electronics introduce a variety of solutions (Optical solutions, Thermal solutions, Electrical solutions, Electrical devices, Connectors, Sockets) that may be used to handle and assemble Citizen Electronics LED package approved or qualified suppliers for customers convenience. It is the responsibility of the customer to fully qualify and validate luminaire design components and assembly processes to meet all code and regulatory requirement. Please check the detail at the URL site below. This information contained in URL may be changed without notice. Top page of solution information URL http://ce.citizen.co.jp/lighting_led/jp/technology/solutions/index.html Optical solutions Introducing manufacturers who provide lenses, reflectors or holders for our LED packages. URL http://ce.citizen.co.jp/lighting_led/jp/technology/solutions/lens.html Thermal solutions Introducing manufacturers who provide heatsink, thermal interface materials for our LED packages. URL http://ce.citizen.co.jp/lighting_led/jp/technology/solutions/heat.html Electrical solutions Introducing manufacturers who provide power supplies, drivers for our LED packages. URL http://ce.citizen.co.jp/lighting_led/jp/technology/solutions/power.html Electronic devices Introducing manufacturers who provide electronic devices for our LED packages. URL http://ce.citizen.co.jp/lighting_led/jp/technology/solutions/device.html Connectors Introducing manufacturers who provide connectors for our LED packages. URL http://ce.citizen.co.jp/lighting_led/jp/technology/solutions/connector.html Sockets Introducing manufacturers who provide Socket for our LED packages. URL http://ce.citizen.co.jp/lighting_led/jp/technology/solutions/socket.html 15 Copyright © 2010 CITIZEN ELECTRONICS CO., LTD. All Rights reserved. CITIZEN ELECTRONICS CO., LTD. 1-23-1, Kamikurechi, Fujiyoshida-shi, Yamanashi, 403-0001, Japan Tel. +81-555-23-4121 http://ce.citizen.co.jp Ref.CE-P2468 03/13 ● CITIZEN ELECTRONICS CO., LTD. shall not be liable for any disadvantages or damages resulting from the use of technical information or data included in this document or the impossibility of download and use, responsibility for the cause of lawsuit or any other damages or losses. ● This technical information or data shall be provided ‘as is’ to users and CITIZEN ELECTRONICS CO., LTD. does not guarantee the absence of error or other defects in this technical information or data, conformance of this technical information or data to specific purpose, this technical information or data or its use will not infringe the rights of users or third parties or any other content. ● CITIZEN ELECTRONICS CO., LTD. reserves the right to make changes to technical information or data without notification. Information contained in this document such as sentences, photographs and images is subject to copyright, and is protected by law. Unless it is for “duplication for private use” or “quotation” under copyright law, any duplication or diversion of this information without permission of CITIZEN ELECTRONICS CO., LTD. is prohibited by law. CITIZEN ELECTRONICS CO., LTD. 1-23-1, Kamikurechi, Fujiyoshida-shi, Yamanashi, 403-0001, Japan Tel. +81-555-23-4121 http://ce.citizen.co.jp Requests / Inquiries [email protected] Website for LEDs for lighting http://ce.citizen.co.jp/lighting_led/jp/ Ref.CE-P2468 03/13