COB (LC013B, LC026B, LC040B) Strategy Marketing Team SAMSUNG Electronics
Index 1. Introduction 1 General structure of luminaire 2. Precautions 2 3. Assembly Process 3 1 Preparing Wire 2 Soldering Wire 3 Fixation of COB
Why mechanical guideline is needed? The COB itself could be assembled onto the substrate or lighting fixture. Therefore, they generally don t need any automatic surface mounting process. The below figure shows several key components, which are basic and important in a LED lighting. These parts are, in most cases, to be manually assembled by hand. During the manufacturing it is likely to have a more potential failure than that in an automatic process. And therefore, the mechanical guideline (for example install guide) should be very helpful to manufacture the lighting luminaires. In this document, the mechanical guideline are available for assembling a lighting fixture using Samsung COBs. - Precautions for mechanical treatment of Samsung COB - Assembling procedure to be recommended General structure of LED lighting The lighting is mainly composed of three major core parts like a heat sink, a power supplier and lighting part (lighting source and 2 nd optic components like a lens, reflector and diffusing plate). The COB is most important lighting source, which perform on the basic lighting and electrical characteristics. Heat sink is closely related with the operation conditions of COB, which may influence on the degradation of luminous properties in lighting. So it is very important to design a optimum heat sink and to attach COB to a heat sink for good heat dissipation. Diffusing plate Reflector Screw and Washer Electrical Wire COB Thermal Interface Material Heat Sink Example of lighting fixture Including COB 1
2. Precautions All users have to read these precautions before handling Samsung COBs. Environment of Working place The working area for assembly luminaire is recommended to be maintained clean for preventing any contamination and keeping workers safety. If all working area cannot be maintained clean, at least the space for assembly have to be kept clean Handling COB 1 Users have not to touch the lighting emitting surface(les) in any cases. At LES (Lighting Emitting Surface), the resin and phosphor cannot protect the bonding wire from deformation or disconnection by an external force 2 Users have to wear the anti-static gloves or anti-static wrist band. 3 When handling COB, user have to use the anti-static tweezers. (Especially, a sharpened-tip of the tweezers would have high possibility of giving a physical defect to COB) The sharp tip may physically damage the resin of LES 4 When switching on COB with an electrical power supplier, an unexpected or abrupt current should bring about EOS failure in COB. This may also bring about the failure in use or the decrease of life time of products. Please discharge the stored voltage of the power supplier. Bending COB 1 Because the substrate material of COB is aluminum alloy, it is easy to be plastically deformed by a physical force. Although COB is mounted on heat sink or lighting fixture, users have to avoid any unnecessary forces which can bring about any strain. 2The site for fixation of COB have to be flat, smooth and clean surfaced. 3 When fixing COB onto a fixture, the pressure should be uniformly put on COB. Chemical compatibility During manufacturing luminaire, the many chemicals could attack and contaminate COB. It is necessary to avoid the contaminants and chemicals in manufacturing process and operation. And we are providing the guideline for chemicals and relevant failure mode. (Refer to chemical guideline). Contamination and cleaning In the production of luminaire, COB can be contaminated by an unexpected contaminant. The organic material like as solder flux have to be cleaned out by using the tip of cotton swap soaked isopropyl alcohol(ipa). 2
Assembling process by using COB In order to bond COB onto an heat sink or luminaire, the fixation generally proceed in two steps. First step is soldering a wire to COB. The second step is attaching COB onto the fixture. In this document, the manual wire connection and fixation are described in order. General Procedure - Cutting the wire at length needed - Peel off the tip of wire and connect wire to COB - Assembling(Attaching) COB onto Heat sink (Lighting Fixture) - Inspection 1 Preparing Wire : Before connecting wire, wire have to be prepared at the length needed according to the right methods. The thickness of wire is mainly dependent on the assigned maximum ampere. The below table is available to select the optimal wire thickness with the maximum ampere ratings. In order to strip the end of wire, the optimal tool and method should be used for the safe and stable operations. AWG Area ( mm2 ) Assigned maximum Ampere rating (A) Prepared Cable 19 0.653 1.800 20 0.518 1.500 21 0.41 1.200 AWG26-19 (0.129~0.653 mm2 ) 22 0.326 0.920 23 0.258 0.729 24 0.205 0.577 25 0.162 0.457 26 0.129 0.361 Amperage vs. wire size of copper conductor from UL486E 3
Assembling process by using COB 2 Soldering wire For COB, it needs to be directly wired by soldering electrical wire. - Considered Materials It is most important to select the good materials for soldering. This would give an effect on the performance and reliability of lighting. And this will be eventually related with the life span of products Solder material : the soldering wire is recommended to be pb-free solders. Soldering flux : Using the soldering flux have to be carefully done so as not to leave a lot of flux residue. And after soldering, the residue of flux must be removed by isopropyl alcohol - Wire connection procedure Flux dispensing Alignment of Wire Soldering Cleaning In process of flux dispensing, the optimum amount of flux must be carefully dispensed only on the electrode Wire orientation have to be determined on the structure of luminaire Soldering have to be done with optimal amount of solder. The below figure shows the good example of soldering with the amount of solder. After soldering, the excess flux, dirt and other contaminants should be removed with cotton swap and isopropyl alcohol(ipa). (a) Minimum amount (b) Optimal amount (c) Excess amount Flux dispensing Soldering In line wire orientation Parallel wire orientation 4
3. Assembly Process _ 3 Fixation of COB 3 Fixation of COB This chapter depicted the how to fix COB at the predefined site. Although many fixation methods can be treated, the two basic method will be mentioned in the point of cost and convenience. The first is using the fixation screw, the second is using the holder, which are provided by holder makers. - Using fixation screw This COB could be fixed by fastening 2 pairs of screw and washer. The concaved corner is adequate shape for fixing COB with screws of M4. As shown in below figure, the two of 4 corners, which is just for fixing screw. The size of screw and hole is recommended in below table. The 2 corners close to electrode pads should not be allowed to fix screw. It is highly possible to bring about the electrical shortage. The torque for fixing screw is recommended to be 0.7~1.0 N m. Screw 1 Screw2 Screw Lock washer Flat washer Screw size Washer size Screw Hole size M4 M4 4.7± 0.1mm - Using holder for COB The using the holder is very convenient way to fix COB, to connect wires and to attach 2 nd optics like reflectors. Most features of holder are that the holder makes the electrical connection without soldering. This means that there is no need for a hot plate and for ventilation duck for exhausting fume. Considering holders, the luminaire is consisted of the key parts like as shown in below figures. As described earlier, three main parts could be functioned as thermal, optical and electrical. The holder play the role which can connect all key parts so as to perform the their functions. This means that the holder is very simple way to fix the COB or to manufacture the luminair. Heat Sink TIM LED Holder Reflector Fixation method [Source : TE type Z50 LED holder Brochure for Samsung COB ] 5
Date Revision History 2013.09.15 New Version 8