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LED ( ) Long Win Science & Technology Co., Ltd. +886-3-4643221 E-mail: longwin@longwin.com Web Site: www.longwin.com

1. 2. -MCPCB 3. - 4. - 5. - / 6. Q&A. 3

度量 5

Tamb Tamb Heat sink Heat Pipe TIM Tj PCB TIM Heat Pipe Heat sink PCB T_j 6

1. A. Conduction B. Convection C. Radiation Q conduction Q convection Q radiation T ka X ha( Ts Ta) A( Ts 4 Ta ha( Ts Ta) 4 ) 7

1. LED 2. 3. 4. 5. ( ) 6. 7. (SRC) 8. 8

冷冷路路料 9

2. -MCPCB 10

MCPCB Al Cu (mm) 1.5 0.065 0.035 I I (. 2 /W) 0.075 0.325 0.0009 0.4 K* 237 2 385 13

(Thick film) (LTCC) (DPC) 16

LED DBC (Al 2 O 3 / AIN) layout 2~3 W/mK 10~22 W/mK LED 200~800 W/mK 24~170 W/mK LED 800 24~170 W/mK 17

3. - Thermal Interface Material (TIM) 18

Thermal Resistance Analysis Tamb Tamb Heat sink Heat Pipe TIM Tj PCB TIM Heat Pipe Heat sink PCB T_j 19

Contact Resistance Contact Resistance = F( roughness, pressure, temperature, material,..) Contact Resistance = Rc_upper + Rc_lower Total Thermal Resistance = R TIM + Rc_upper + Rc_lower 20

3.1 21

3.2 24

( ASTM D 5470) Press Q out T L3 Pad / Grease Tc Th Thermal isolated material Q h Heat Source T L2 T L1 Tu Tm T Q in = I V 25

ASTM D 5470 Fourier Law Q K A T h L T c Q T KA X R dt Q t K.A Thermal resistance ( /W) I R.A t K Thermal impedance (.cm 2 /W) K t I Thermal conductivity (W/m ) 26

ASTM D 5470 27

TIM K Measurement C p Transient k C p m s = Thermal diffusivity = Density = Heat capacity 2 Steady state T Q k A X ( Fourier law) m s 2 m s m Velocity Length C 1 V L 28

TIM K Measurement 1. Laser flash (Transient) 2. Hot disk (Transient) 3. Hot wire (Transient) 4. Heat flux (Steady) 29

2.3 ASTM D5470 Pad 30

PCM 32

Power Cycle 34

4. - 35

Container / Wick Structure / Working Fluid 36

Mesh Powder Groove 37

Thermal Response Thermal resistance Max. Heat Transfer Rate (Q max ) 39

W1 Weff W2 R1 R2 Weff W1 W 2 40

Coarse Pore Wick Fine Pore wick Sinter Powder Wick 43

LED 40/45mil Size LED Chip 1W Chip Heat Flux Almost= 100W / CM 2 3W Chip Heat Flux Almost= 300W / CM 2 Heat Flux IS Very High (Compare With CPU 60~130W/CM 2 ) High Heat Density (Hot Spot) Is the Key 44

Solve the Hot Spot of LED Chips Heating Area Vapor flow Top cover Wick Structure Bottom cover 45

Experiment 1 1. IR Camera 2. DC fan 3. LED on case1 or case 2 2 3 Case 1 Put LED on extruded AL heat sink. Case 2 Put LED on vapor chamber with extruded heat sink. Case 1 : Extruded AL heat sink Case 2 : vapor chamber on extruded AL heat sink 46

12W LED package 1-1 2-1 1-2 2-2 1-3 2-3 IR result for case 1 (Al heat sink only) IR result for case 2 (VC+Al heat sink) 1-1 : 58 1-2 : 29 2-1 : 55.2 2-2 : 31.2 47

10W thermal resistor 2-3 2-1 2-2 1-3 1-2 1-1 IR result for case 1 (Al heat sink only) 1-1 : 80.4 1-2 : 57.6 1-3 : 55.5 IR result for case 2 (VC + heat sink) 2-1 : 67.1 2-2 : 57.6 2-3 : 56.2 48

The Thermal Solutions For High Power LED II LED Chips Directly Bonded On Vapor Chamber Silicon Lens LED _Chips Solve the Heat Problem of Package Vapor Chamber Heat Sink 1. Substrate Removed. 2. Heat Spreader( Vapor Chamber ) LED Multi-chip using COB directly mounted on our VC. 3. Heat Sink Dissipates the Heat to Air 49

Thermal Solutions For High Power LED II Direct Bonding On VC Cu Substrate 50

Thermal Solutions For High Power LED II Cu VC 51

Thermal Solutions For High Power LED III LED Emitters Solder on Vapor Chamber using SMT Vapor Chamber SMD LED Emitters Circuit Layer Heat Sink 52

Thermal Solutions For High Power LED III The Prototypes of SMT Type Vapor Chamber For Cree XRE Series Vapor Chamber PCB With Cree XPG Series 53

4.3 (LHP) 54

5. - / Q = h A T For natural convection, h ~ 5 W / m 2 K 59

Schematic of induced main flow for pin fin and plate fin geometry. 61

Schematic of experimental setup 62

Total power input : Total heat loss : Heat transferred by heat sink : Heat transferred by Convection : Heat transferred by Radiation: 63

Schematic of induced main flow for a flat plate subject to three orientations Schematic of induced main flow for pin fin geometry subject to three orientations 64

- Optimum Spacing of Heat Sink 65

Relationship: Q C A 2 g d H NP H Q = flow rate in cfm, Cd = 0.65 (for unobstructed openings), A = opening area, square feet, Ti = indoor temp (Rankine), To = outdoor temp (Rankine), Hnp = height of "neutral pressure point (for simple systems, assume 1/2 way between top and bottom openings). Hb = height of bottom opening g = gravity. b T i T T i o P S i g H H NP T i T T o o 67

CFD

Flow Visualization Link Movies A. Natural Convection B. Force Convection

5.2 - / Cooler

Introduction Principle Operation Calibration Features Model Flow Pattern with Cooler Performance 83mm 69mm 45mm A B C D E

Introduction Principle Operation Calibration Features Model

Introduction Principle Operation Calibration Features Model 1 Lowest Fan rpm

Augmentation with the interrupted surfaces Thermal boundary layer restart

Augmentation with the interrupted surfaces Thermal boundary layer restart Fin patterns (for finned tube heat exchanger)

Augmentation - vortex generators

LED Liquid Cooling 81

Q & A 82

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