SMT Magazine: LED Thermal Management 2.0
Upcoming SlideShare
Loading in...5
×
 

SMT Magazine: LED Thermal Management 2.0

on

  • 1,840 views

New pie

New pie

Statistics

Views

Total Views
1,840
Views on SlideShare
1,840
Embed Views
0

Actions

Likes
1
Downloads
33
Comments
0

0 Embeds 0

No embeds

Accessibility

Upload Details

Uploaded via as Adobe PDF

Usage Rights

© All Rights Reserved

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Processing…
Post Comment
Edit your comment

    SMT Magazine: LED Thermal Management 2.0 SMT Magazine: LED Thermal Management 2.0 Document Transcript

    • EnginEEring solutions for pcb manufacturing Electronics Forecast: Hot andwww.smtonline.com Getting Hotter p.16 ju ly 2 0 1 1 Stategies for Beating the Heat: Recent Developments — LED Thermal Management 2.0 p.22 TECs and Micro TECs for Spot Cooling on Electronics p.28 Thermal Stress in Electronic Packaging p.32 July 2011 • SMT Magazine 1
    • Thermal Management Strategies for Beating the Heat:Recent Developments — LED Thermal Management 2.0by Yash Sutariya on an online registration form. With the rise ofSATuRn ELECTROnICS CORPORATIOn/ LEDs, however, thermal management’s role isSATuRn FLEx SySTEMS now prominent and designers are proactively addressing this discipline from the beginning. The process has been analyzed, taken apart and put back together while examiningIn SuMMARy the inter-relationships between each element in the finished product stack-up. We’veWith the LED market exploding while still come a long way, but there are still loomingin its infancy, both PCB producers and end challenges.users can expect to see consistent evolution We believe that there is always a solution.in not just standard MCPCB materials, but You joined us in checking that long-dormantalso potentially disruptive and game-changing thermal management requirement box…nowtechnologies and applications. we’re ready to start looking outside of it. For that, we turn our attention to Technology Evolution: LED Thermal Management 2.0. For the past two and half years, the PCB Where We’ve Beenindustry has been beating the heat as if we For the past two years, we’ve invested awere Dirk Nowitzki and the Dallas Mavericks. significant amount of resources into educatingSpeaking from the PCB fabrication link in the the industry to properly calculate their needssupply chain, the approach taken has been one based on commonly accepted methodologiesof refining loose methods of operation into a and materials. Instead of calling out thermally-finely-tuned best practice methodology. conductive MCPCB materials by brand name Prior to the recent rise of the LED, PCB (or no name at all), we have had industrythermal management was an afterthought and experts define material properties and showan obstacle—like one too many required fields us how to calculate our needs. (We’ve made a22 SMT Magazine • July 2011
    • Thermal Managementyear of promises, but the online version of the flex and rigid-flex PCB industry) proposed aLED Thermal Resistance Calculator is finally reasonable alternative.up-and-running.) Keep in mind that thermal conductivity The central purpose asserted in each of values are almost meaningless without takingthese various presentations was constant: thickness into account. Most thermallyCalculate your needs in terms of maximum conductive materials have a minimumthermal resistance, minimum electrical thickness of 0.003” to 0.004”. However, oninsulation and any other properties you felt a daily basis flex shops are using materials aswere critical to product performance. Then, thin as 0.001”. Therefore, even with a lowerlet your supplier search the globe for the most thermal conductivity value, a material thiscompetitive solution both in terms of pricing thin would pose very little thermal resistance.and lead time that meets your needs. Moreover, the flex PCB wraps around the Now that we’ve firmed up the ground four sides of this light post while the FR4we’ve been walking for years, it’s time to shake stiffener ensures thermal transfer by allowingthings up and rely on the innovation that has the PCB to be directly screwed to the metalhelped our industry survive for decades. As lamp housing.with any other successful industry, we foresee Initial tests showed that the time tomaterials and product evolution to change the equilibrium was approximately half that of thecurrent landscape in the coming years. prior design. Here are a few product innovations that, Click here for Flex LED PCB Kit.I believe, will emerge to address technologyrefinements: 1) product design; 2) material Material Improvementsimprovements; and 3) alternative materials/methodologies. Thermally Conductive Dielectrics As end users become emboldened withProduct Design their newfound calculators and materials One gripe about MCPCBs is that they are testing methods, thermally conductive materialentirely two-dimensional and the product manufacturers have been coming out ofmust be designed to conform around the the woodwork with either new or improvedPCB. We came across one such limitation alternatives to those offered by the currentin regards to a three-dimensional lamp post establishment. We are approached almost on aapplication with a customer who was using weekly basis with new products offering lowerfour separate MCPCBs and connecting them cost or increased performance, or both. We tryaround the corners of the post using to keep our materials comparison chart updatedsoldered wires. but, with the frequency of new materials being Now, thermally conductive substrates, offered, it’s certainly a difficult task.regardless of brand, are all polymers. Thus, For the most part, continued innovationthese thin materials (commonly used in the has enabled materials manufacturers to improve the filler’s performance in increasing thermal conductivity, while simultaneously reducing thermal resistance by laminating dielectrics in thinner layers. While these are not game-changing technologies, if you will, at the end of the day they represent incremental improvements to the currently accepted technology base. Remember when you thought your two- pound Walkman was the cat’s pajamas? Don’t be surprised to see mainstream laminate manufacturers enter this market within the July 2011 • SMT Magazine 23
    • STRATEGIES FOR BEATING THE HEAT continuesthermal management next six to 12 months with product offerings that reduce cost and increase performance. Inks for Printed Electronics Over the past decade, the disruptive tech- nology of printed electronics has been making significant gains in flexible display/touch screen, smart label and flex PCB market share. Regardless of medium, the potential for direct materials savings and streamlined production accounts for a motivating one-two knockout punch. Alternative Materials/Methodologies One of the most interesting ideas we’ve played around with was the use of Pyrolytic Graphite embedded into FR4 material to achieve thermal conduction to the heatsink. With a thermal conductivity value four times Printed electronics involves screening electrically conductive inks (as opposed to etching copper circuits) and is used primarily on low-voltage applications since the inks to date have had too high an electrical resistance. As evolution dictates, there has been significant progress in reducing the electrical resistance of inks. We were approached by one of these manufacturers to help evaluate their ink for LED applications. While this is still in progress, the benefits of printing directly to a coated metal substrate are clear: The elimination of the often expensive and hard- to-procure thermally-conductive dielectric that is common to MCPCBs. At the moment, thermal and electrical material properties (responsible for electrically insulating the barrier between the conductive ink and the metal base) prevent this realization; for this purpose, prepreg, anodizing and even a simple coating of soldermask are being considered. “Tucker, the Man and His Dream” Paramount Pictures. 24 SMT Magazine • July 2011
    • STRATEGIES FOR BEATING THE HEAT continuesthermal management that of pure copper, Graphite PCB seemed It may no longer be the Wild West, but like a home run; however, cost and process let’s not get comfortable with the status quo! limitations represented challenges. Let’s make a commitment to keep the burr in I was about to submit this concept to our saddles. SMT the Tucker Motor Cars Hall of Fame when I received a phone call from a materials *Standard PCB materials are comprised of a manufacturer with a novel idea: Replace weave of fiberglass coated with epoxy (typically the fiberglass yarn* with carbon fiber that FR4 or Polyimide). has a thermal conductivity in excess of 200 W/mK. Hold that Tiger! Not only can you drill and plate through nicely, but the carbon yash Sutariya received his BBA from fiber acts as a heat spreader in the X, Y and the university of Michigan’s School Z axes. of Business Administration. After While the material for this particular is graduation, he worked in Valuation still under development, with some creative and Bankruptcy/Turnaround process applications it could surely be a Consulting. He is currently Vice game changer offering the potential for both President of Corporate Strategy significant performance increases as well as at Saturn Electronics Corporation (SEC) and modest cost reductions. Owner/President of Saturn Flex Systems, Inc. Conclusion Since joining the team, SEC has successfully With the LED market exploding while still navigated from a low-mix, high-volume in its infancy, both PCB producers and end automotive supplier to a high-mix, medium- users can expect to see consistent evolution to high-volume diversified supplier. As a in not just standard MCPCB materials, but result of the company’s transformation, also potentially disruptive and game-changing manufacturing capabilities now range from technologies and applications. quick-turn prototypes to scheduled volume The main concern is whether or not we are production while attending a broad cross-section keeping an open enough mind to see the value of industries to include industrial controls, proposition in these, and what are we going telecommunications, aerospace and power to do to foster and encourage out-of-the-box supply industries. thinking? 26 SMT Magazine • July 2011
    • PUBLISHER: Barry MaTTieS EDITORIAL ADVISORY BOARD continued barry@iconnect007.com MiCHaeL KONraD, Aqueous Technologies PUBLISHER: ray raSMUSSeN S. MaNiaN raMKUMar, PH.D., (916) 294-7147; ray@iconnect007.com Rochester Institute of Technology ray P. PraSaD, Ray P. Prasad Consultancy Group SALES MANAGER: BarB HOCKaDay (916) 608-0660; barb@iconnect007.com rOBerT rOWLaND, RadiSys Corp. VerN SOLBerG, Tessera Technologies Inc. EDITORIAL: Gary TaNeL, Circuitronics GROUP EDITORIAL DIRECTOR: ray raSMUSSeN (916) 294-7147; ray@iconnect007.com HaraLD WaCK, PH.D., ZESTRON America WiLLiaM e. COLeMaN, PH.D., Photo Stencil MANAGING EDITOR: HOLLy COLLiNS (252) 288-5118; holly@iconnect007.com MAGAZINE PRODUCTION CREW: TECHNICAL EDITOR: PeTe STarKey PRODUCTION MANAGER: SHeLLy STeiN +44 (0) 1455 293333; pete@iconnect007.com shelly@iconnect007.com MAGAZINE LAYOUT: rON MeOGrOSSi EDITORIAL ADVISORY BOARD: AD DESIGN: SHeLLy STeiN, BrySON MaTTieS CraiG HUNTer, Vishay INNOVATIVE TECHNOLOGY: BrySON MaTTieS JeNNie S. HWaNG, PH.D., H-Technologies Inc. COVER ART: SHeLLy STeiN, BrySON MaTTieS SMT® (Surface Mount Technology) is published by BR Publishing, Inc., PO Box 50, Seaside, OR 97138 ©2011 BR Publishing, Inc. does not assume and hereby disclaims any liability to any person for loss or damage caused by errors or omissions in the material contained within this publication, regardless of whether such errors or omissions are caused accidentally, from negligence or any other cause. July 2011, Volume 26, Number 7 • SMT© (Surface Mount Technology©) is published monthly, by BR Publishing, Inc. Ad IndexAdvances in Thermal Mgt. Conf... 69 Next Month in SMT Magazine We all greatly depend on our electronicsAegis............................................ 39 devices—perhaps a bit too much. We expectBlackfox....................................... 49Calumet Electronics...................... 45 them to work under a wide range of conditionsCA Picard..................................... 27 and failures can not only be irritating, but alsoChina Fastprint............................. 43 life-changing. The August issue of SMT MagazineDigi-Key Corp............................. 1, 2 will highlight high-reliability electronics withEasyBraid Co................................. 47 articles to help you make sense of processEPEC............................................. 19 requirements, detection, new and evolvingHunter Technology Corp............... 31 strategies (Occam and others), and help solveImagineering Inc......................... 7, 9IPC.......................................... 71, 73 issues such as tin whiskers.Lenthor Engineering..................... 33 We’ll feature articles from these industryManncorp...................................... 5 experts: Photo Stencil’s Dr. Bill Coleman willMeptec......................................... 67 discuss step stencils; Dr. Mike Pecht of CALCENordson Asymtek......................... 25 and Dr. Sanjay Tiku of Microsoft will focus onP. Kay Metal................................. 53 counterfeit products in military systems; CraigPrototron Circuits......................... 41 Hillman, Gregg Kittlesen and Randy Schueller ofSMTA........................................... 61 DfR Solutions will tackle a better approach to tinSunstone Circuits......................... 59Technica USA............................... 13 whisker mitigation; and many, many more.Ticona.......................................... 55 If you’re not yet a subscriber, don’t miss out!Totech.......................................... 11 Click here to receive SMT Magazine in yourTTM Technologies........................ 65 inbox each month.U.S. Circuit................................... 63 See you in August!Zestron......................................... 21 July 2011 • SMT Magazine 77