LED光源散熱設(shè)計方法

1、鄒靜 （）GBU LED Lamps and SystemsJune 2010General Guide to the Heatsink Design for Fortimo modules ConfidentialGBU LED Lamps and Systems, June 20102Nice to know: Product leaflet; Design-in guide; Optical files; Catalog; Photometric files Certificates 3D file such as CAD fileConfidentialGBU LED Lamps an

2、d Systems, June 20103LED 模組會因為沒有接散熱器，過度受熱而壞掉模組會因為沒有接散熱器，過度受熱而壞掉嗎？嗎？ConfidentialGBU LED Lamps and Systems, June 20104LED 模組會因為沒有接散熱器，過度受熱而壞掉模組會因為沒有接散熱器，過度受熱而壞掉嗎？嗎？不會, 我們的模組有高溫保護功能，一旦模組溫度升到一定值，驅(qū)動器的輸出電流會自動減小，這會阻止模組溫度繼續(xù)升高。ConfidentialGBU LED Lamps and Systems, June 20105 LED Performance issue? Tj必須保持在特定

3、的溫度下，以免顏色飄移， 或者光通的改變。 Why Bother?ConfidentialGBU LED Lamps and Systems, June 20106 LED Performance issue? Tj必須保持在特定的溫度下，以免顏色飄移， 或者光通的改變。 Lifetime concern? 焊點經(jīng)歷一定次數(shù)冷熱循環(huán)后（熱脹冷縮的循環(huán)）會產(chǎn)生脫節(jié)。一般來說，焊點的溫度越高，脫節(jié)前經(jīng)歷的冷熱循環(huán)數(shù)越低。 Why Bother?ConfidentialGBU LED Lamps and Systems, June 20107 Tc 對于模組來講,只要 Tc保持在 650C or 5

4、50C, lifetime（B50L70）會在50000個小時左右。LLM模組由于具有CLO，所以lifetime不使用L70。 Tc and LifetimeModuleTc life (0C)DLM65Lexel65SLM65LLM55Twistable55ConfidentialGBU LED Lamps and Systems, June 20108Special features Fortimo LED linearConfidentialGBU LED Lamps and Systems, June 20109 多少的功率（百分比）變成了熱? ConfidentialGBU LED

5、 Lamps and Systems, June 201010How much power is turned into heat?一般來說一般來說, 有 remote phosphor的模組, 比如：2/3 的模組消耗的功率（系統(tǒng)功率 驅(qū)動器的功率）轉(zhuǎn)變成了熱。ConfidentialGBU LED Lamps and Systems, June 201011How much power is turned into heat?一般來說一般來說, 有 remote phosphor的模組, 比如：2/3 的模組消耗的功率（系統(tǒng)功率 驅(qū)動器的功率）轉(zhuǎn)變成了熱。RemotePhosphorTc

6、(C) POptical (W)Power module only WattWPEOpen5514.6532.844.71%4000K559.2432.828.17%3000K558.5732.826.13%1-45% = 55% 的功率轉(zhuǎn)換成熱!1-26% = 74% 的功率轉(zhuǎn)換成熱!轉(zhuǎn)換成光的效率ConfidentialGBU LED Lamps and Systems, June 201012How much power is turned into heat?一般來說一般來說, 有 remote phosphor的模組, 比如：2/3 的模組消耗的功率（系統(tǒng)功率 驅(qū)動器的功率）轉(zhuǎn)變成了

7、熱。Remote PhosphorTc(C) submountPOptical (W)Power module only WattWPEOpen5514.6532.844.71%4000K559.2432.828.17%3000K558.5732.826.13%Side story!ConfidentialGBU LED Lamps and Systems, June 201013How to get rid of heat?被動散熱主動散熱Thermal management:Heat spreading （傳熱）（傳熱）: 把熱傳到一個更大的面積Heat sinking （散熱）（散熱）:

8、 通過convection（熱對流）和radiation（ 熱輻射）使熱傳到空氣環(huán)境中。ConfidentialGBU LED Lamps and Systems, June 201014Thermal Management Heat spreading主要的傳熱機制（從模組到散熱器）是conduction（導(dǎo)熱）;為了增加模組和散熱器之間的熱傳導(dǎo)，一般要使用thermal interface materials (導(dǎo)熱介質(zhì)), 比如導(dǎo)熱膠，或者導(dǎo)熱膜，甚至導(dǎo)熱管.散熱器要用thermally conducting material（導(dǎo)熱材料）（導(dǎo)熱材料） 金屬是比較好的導(dǎo)熱材料 很多情況下鋁

9、是首選，因為造工比較方便，價格也比較合適。ConfidentialGBU LED Lamps and Systems, June 201015Thermal Management Heat sinking (Convection) 影響熱對流的因素如下: 熱對流系數(shù) Pconv = hc* Aeff* (Tc-Tamb), 有效面積 熱阻(Rth)如下: Rth= T/Pheat = 1/ (h* Aeff* ) 熱功率 Tcase環(huán)境溫度ConfidentialGBU LED Lamps and Systems, June 201016主動散熱和被動散熱的比較： ConfidentialGB

10、U LED Lamps and Systems, June 201017Thermal management Heat sinking (Radiation) 熱輻射的影響因素也可以寫成如下： Prad = hr *Aeff* (Tc-Tamb), 熱輻射系數(shù) 熱輻射因素和emission coefficient(放熱系數(shù))成正比，而emission coefficient 和 表面處理有關(guān)：ConfidentialGBU LED Lamps and Systems, June 201018Thermal management Heat sinking (Radiation) 整個散熱（熱對流

11、 + 熱輻射）： Pheat = h * Aeff* (Tc-Tamb), 在我們模組的工作范圍內(nèi)，一般來說，熱輻射在整個散熱中占到 20% - 40% 左右，整個的傳熱系數(shù)在2-10之間。ConfidentialGBU LED Lamps and Systems, June 201019Heatsink ExamplesPassivePassivePassivePassiveActiveActiveConfidentialGBU LED Lamps and Systems, June 201020要考慮的因素： 用導(dǎo)熱性能好的材料 鋁是較好的選擇 散熱器的整個有效面積 Aeff = 1/ (

12、h*Rth) 散熱片的擺放位置 散熱片之間的距離 散熱片的長度 散熱片的厚度 用放熱系數(shù)較大的表面處理 鋁一般用噴漆或者陽極 為了保證模組和散熱器之間的熱傳導(dǎo)，要用導(dǎo)熱介質(zhì)ConfidentialGBU LED Lamps and Systems, June 201021Heatsink verification: Measuring Tc (with heatsink attached) The stabilization time for Tc can be between half an hour up to 3 hours, which depends on the measureme

13、nt environment. In general, it takes longer to stabilize in an enclosed environment, such as a simulated ceiling environment. Thermal couple can be used to measure Tc. Ensure good contact between the thermal couple and the module by taping (aluminum tape) or applying a thin layer of quick drying glu

14、e and string relief Thermal couple has certain dimensions, so it is not recommended to put them between a module and a heat sink directly unless there is already a groove made on the heatsink. However, Tc can also be measured towards the side of the module, which of course will be a few degrees less

15、 than the temperature in the center.ConfidentialGBU LED Lamps and Systems, June 201022樣例: 模擬的天花板環(huán)境中Tc的測量Tc等了1-2小時候才穩(wěn)定； 一般來講，在一個封閉的環(huán)境中，Tc要等比較長的時間才可以穩(wěn)定下來ConfidentialGBU LED Lamps and Systems, June 201023樣例: Tc 在敞開環(huán)境中的測量盡量避開空氣流動比較大的地方！盡量避開空氣流動比較大的地方！+ 100C56.80CT_ambientConfidentialGBU LED Lamps and Sy

16、stems, June 201024ConfidentialGBU LED Lamps and Systems, June 201025DLM: 在U型的邊上測如果散熱器安裝在DLM的底部，邊上的溫度應(yīng)該610C，只要可以基本保證Tc650CSimulation made with heatsink attached to the sides.ConfidentialGBU LED Lamps and Systems, June 201026散熱器設(shè)計的流程 收集基本的一些信息，比如多少的熱功率，以及設(shè)計上的一些形狀或者 大小的限制等等； 把以上信息輸入到熱學(xué)軟件中,進行計算機模擬; 初步判斷

17、模擬結(jié)果對散熱器設(shè)計進行修正; eg. Mould the first heatsink and do extensive real temperature testing. ConfidentialGBU LED Lamps and Systems, June 2010Measurement results240mmx60mmx30mmWhat is h?ConfidentialGBU LED Lamps and Systems, June 201028What is h?A = 0.24x 0.03 x 9 x 2 = 0.13m2T = 52-25.6 = 26.40CP_heat = 16WP_heat = h * A * TSo h = 16/(0.13 * 26.4) = 4.6 W/m2 0C現(xiàn)在我們知道了h,下一步就要回到紅色標(biāo)示的公式去計算所需要的面積! 改進已有的散熱器,再進行測量,直到達到需要的Tc.ConfidentialGBU LED Lamps and Systems, June 201029Heatsink VendorsBelow are a few links to professional heatsink providers: For passive cooling: AVC: http:/.tw/ For