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Introduction of COBAdvantage and disadvantage of COB module

2014. 06. 13.

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Lighting is a technology with a purpose to contribute to human beings in all aspects of life.From the beginning of human history, Lighting technology have been developed from torchlight based on SUN light to the fluorescent lamps representing the modern age.Lighting is classified into Indoor, Outdoor, Special lightings, and the normal light source familiar with us is indoor lighting in most parts.Outdoor lighting is for Street lights , commercial sign boards, traffic lights, and sustained mainly By electrical engineers.Special lightings is BLU for Celluar phone and TV and vehicle head lights etc.

▣ Outline of Lighting

▣ History of Lighting

※ One of the semiconductor, LED is expected to replace the conventional lightings like incandescent lamps, fluorescent lamps, with infinite possibility, opening the newhistory of lighting.

▣ Outline and history of Lighting

LED Lamp(white power LED)

Metal Halide Lamp

Halogen Lamp

Flourescent Lamp

Incandescent lamp

16 years

50 years

53 years

74 years

133 years

Data from POSCO LED & SINHAN INVESTMENT

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▣ Strategical Business Area of LED Lighting

LightingLED

products

SpecialLED

products

LEDmaterial

LEDLight

source

For DisplayLED module / System

LCD/TV BLU

Signage

Special

lightings

MaterialsLight source

manufacturing

fixturesPackage(/module

/heat disspation/

power source)

Products

(single/composi

teness)

Indoor

Normal

lightings

Transport light

(land,marine,air,leisure)

Special lights(environment, medical, etc..)

Outdoor

Special LED module

Lighting

LED module

▣ About LED Lighting

Definition : LED( Light Emitting Diode ) is one of the semiconductors radiating the lights when the current flows , and the LED lighting industry uses it to produce LED products.

▣ Business area of LED lighting

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▣ Three methods to extract White Light from LED

Three typical methods of Generating LED White Light

InGaN LEDAlGaAs LED

Blue Green Light

White Light

InGaN LED

Red

White Light

UV LED RGB Phosphor Blue LED Yellow Phosphor

White Light

Red+Green+Blue LEDs UV LED+RGB Phosphor Blue LEDs+Yellow Phosphor

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▣ Comparison between COB LED Module & Package Type

COB : Chip on BoardSMD : Surface Mounting Device The best technology in the world

Without PKG process, LED bare chip is bonded

directly on the heat sink. And it’s finished with

resin molding.

COB type maximizes the heat dissipation

High luminance efficiency

Suitable for downsizing the housing

Wide radiation angle (170 deg.)

Saving the cost compared to PKG type

Deterioration of luminous efficiency and heat

dissipation

The production process is complicated

Narrow radiation angle (120 deg.)

Comparatively high cost

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SMD’s normal Structure review

• applied process: SMT–surface mounting technology

SMD is attached on MCPCB

( LED ) (Metal core base cuircut)

• MCPCB: 40mm*34mm thick:1.5mm• Bonding Area: Dia. 8mm

LED chip bonded on the MCB withsolderMany layers of insulators betweenMCB and mount

Insulator is thin and Heat radiation is comparatively good

Cited : Korean Optical magazine 2010 JuneCOB lamp radiation char. Research.

▣ Comparison between COB LED Module & Package Type

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Heat conductivity of Materials

• Heat conductivity: (3 kind )unit expressing how wellconvey the heat.Kcal / mh C˚w/m²C˚w/mk

1 W/(mk) = 0.8596 cal/h m C˚

1 Kcal = 4.184 J= 4,186.8J

1W = 1 J/s

Coefficient of H²O: 0.6W/mkCoefficient of ICE : 1.6W/mk

Ice convey heat 2.5~3.6 timesbetter than water.

When high conductivity interfaced between the lowsIt acts as heat-insulator,Preventing heat radiation.

Non-

conductor

minerals

▣ Comparison between COB LED Module & Package Type

section

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131 C˚

120 C˚

Temp. diff.:11 C˚

5 layers of materilasWith different condutivity is interfaced oneach others up & down, heat is not easyto be conveyedheat-load is accumulated inside the chip

▣ Comparison between COB LED Module & Package Type

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The reason whyThe temp. dropedIs the insulatorWas removed In meaingful degree,so that the heatResistance droped.

127 C˚

121 C˚

HeatDiff.: 6 C˚

127 C˚

▣ Comparison between COB LED Module & Package Type

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The reason the temp.Has droped greatlyIs because that theInsulators was totallyRemoved.

▣ Comparison between COB LED Module & Package Type

Ni/Ag gilding( for easy soldering )

Temp.diff.: 4 C˚

101 C˚

105 C˚

Solder only between LED bare chip &Metal core Base

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▣ Heat Radiation comparision between SMD Package LED COB Module

The temperatureDifference betweenSMD type andKOREASUNLED’s COB type is26 C˚20% lower level

The temp. of MCPCBis19 C˚16% lowr level

Heat radiation relatesLife span, color Rendeing, Economiceffect.

1. Structure of surface mounting type of LED Package & Thermal simulation data

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▣ Comparision of Optical out and Color rendering changes

LED BLU : 120 mm * 6 mm (thickness:1.6mm )LED chip: 350㎛*350㎛ inGaN/Sapphire kinds

Rated current: Nor. 50mA -> Exper. 200mA

SMD : Output drop big, , Color Cord. Fluctuate Big

COB with insulator : somewhere in the middle

COB (SUNLED) : Output no change, Color cord.almost no change.

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ITEMPower

(W)Q’ty

Power

Consump.

(W)

Luminance

efficiency

Total

Luminance

flux

Luminance

Competitor’s

LED High-bay

(Package)

125 10 1,250 77 lm/W9,625

lm

700~

100lx

KOREASUNLED

LED High-bay120 10 1,200 100 lm/W 12,000lm

528~

220lx

Saving effect

(compared to

Metal-halide

lamp)

70 0Save up to

70%

23% better

than

competitor

s

20%

brighter

than

competitor

s

▣ Comparision of Optical out and Color rendering changes

SMD Package shows various unsuitablenessFor commercial use under increased rated current

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Summery of KOREASUNLED type of COB module’s advantage

1. Heat Radiation : Optical output does not drop even when increased the drive currentdue to the good heat radiation effect

2. Optical Output : Easy to increase the optical output without increasing the numberof LED chips, suitable for the products requiring Big illuminance flux.

3. Color cordinate fluctuation: small fluctuation range looked as important in commercial

4. Application : Suitable for High-power LED products for Lightingsfor the replacement of Metal Hallide, Sodium Lamps=> LED high-bay, Flood light, Street Light, Guard light

50W, 70W, 100W, 150W, 175W

200W, 250W, 350W, 400W

1KW

60W, 80W, 100W

120W, 150W

▣ Comparision of Optical out and Color rendering changes

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COB Contents Remarks

M

E

R

I

T

s

１. Good Optical, Electrical, Heat characteristics

2. Excellent Water tolerance & high temp.

property

3. Superb Electrical Efficiency (over85%,

the most 95%)

5. Good color rendering near to natural light

( R + G + B )

6. Weight lightening,miniatuariation

7. Ecomony in investments

８. No Shadow phenominon

9. Superb Heat radiation effect

10. Easy to make flat light source

11. Simplified production process

12. Suitable for long-distance lighting

13. 20% higher brightness than SMD

High Power COB: 50W~60W of COB mod.

high-bay, flood light, street light, guard

light, tunnel light, etc

integration of 0.2W, 0.3W LED bare

chips in small space

0.2W* 300 = 60W

0.3W* 400 = 120W

0.37W * 432 = 159W

Low Power COB: 5W ~ 20W of COB mod.

Apt. interior, Hotel room, shopping mall

integrated in small space with

0.1W of LED bare chips

0.1W * 100 = 10W

D

E

M

E

R

I

T

s

1. Lens optical technology needed

2. Rapid degradation expected without

reasonable heat management

Optical design manpower secured.

Securing the heat radiation technology and current control technology for COB.

▣ Merits and demerits of COB LED Module

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▣ Merits and Demerits of Package Type Product LED COB Module

characteristics Package Type COB Type

Radiation angle 120 deg. 170 deg.

Thermal radiation Bad Excellent

Using PACKAGE Use Don’t use

Dot Visible invisible ( glare↓ repulsion↓)

Dot defect

Desoldered lead frame

causes faulty per Dot :

Offends the eye

It’s invisible if failures occur because

of using micro mini chip

Price Expensive Cheap

Uniformity of CCT Difficult Easy

Luminance efficiencyLow (75~85lm/W)

Use 1W~3W LED chip, Poor efficiency.

High (100lm/W)

Use 0.06~0.2W LED chip, Good efficiency

Total luminous fluxEmit less total luminous flux

because of low luminance efficiency

Emit much more total luminous flux

because of high luminance efficiency

Degree of integration Difficult : limited to Package size Possible : micro mini size

Lens Apply small lenses (for 1W~3W) Applying big lenses (for 10~50W)

Angle control limited No limit

The range of light with lens Less than 30m More than 150m

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▣ Comparison LED lightings with traditional lightings

Reference (LED lighting)

ITEMLED lighting

(KOREASUNLED)Metal halide lamp Sodium lamp Induction lamp

Shape

Luminance efficiency

Light emission

Light

source Light

source

Light

source

Light

source

Radiation angle

Reflector

Rate of using light

Luminance efficiency

(actually)

Within 140° 360° 360° 360°

needless necessity necessity necessity

More than 95% Below 60% Below 60% Below 60%

Photo

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▣ Comparison LED lightings with traditional lightings

ITEMLED lighting

(SUNLED)Metal halide lamp Sodium lamp Induction lamp

Life time >50,000 hr 9,000 hr 12,000 hr > 50,000 hr

Deciining of total luminance flux very slow fast fastlittle bit slow compared to Metal

halide/Sodium

Maintaining the total luminance

fluxmore than 90% 66% 57.50% 81%

CRI > 80 Ra 60~80 Ra 28~32 Ra 70~80 Ra

Color Various cool warm, uniformed similar to fluorescent lamp

lighting hour immediately impossible impossible immediately

Weight around 4.5 kg (120W) around 6 kg(400W) around 6 kg400W) around 1 kg

Heat

59~70℃Heat dissipation design

required

300~400℃High thermal affects to

products

300~400℃High thermal affects to

products

90℃

Fire/Explosion risk low high high low

The glare no afterimage, little glare little afterimage, much glare little afterimage, much glare no afterimage, little glare

Luminance variability depending

on input voltage

no variability because of using

constant current

variable depending on input

voltage

variable depending on input

voltage

no variability because of using

constant current

Uniformity of color uniform not uniform not uniform uniform

gathering insect very low high low average

plants overgrowth low low high(need to turn off lights) average

The rate of containing mercury ZERO more than 30mg more than 30mg more than 6mg

Accessory Convertor(about 1kg) ballast(about 5kg) ballast(about 5kg) ballast(about 1kg)

Initial investment high average low high

Maintenance cost low high high low

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▣ Comparison between LED Package Type and LED COB Module

ITEM Package Type COB Type(KOREASUNLED)

1.Luminance efficiency

LED PKG decrease luminance efficiency because there is a lot of the light loss through reflector and surface

Luminance efficiency is improved because the surface of COB Module is metal or FR4 PCB

2.Heat dissipation

(A constancy of light)

Insulator makes conductivity low. Because a constancy of light is sharply dropped, it shorten the life of a light.

A constancy of light is improved, because of the structure which LED Chip is directly attached on metal PCB. It makes conductivity high and the life of light longer

Light

HEAT SINK

Light

Heat Sink

Insulator

Metal or FR4 PCB

Conduction

HEAT SINK

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ITEM Package Type COB Type(KOREASUNLED)

3.Miniaturize

It’s difficult to miniaturize because LED Package needs some spaces for mounting devices

It’s able to miniaturize less than ¼ compared to PKG when it’s used for same power consumption.

4.Cost

It’s needed SMD process for LED Package

The cost can be saved, because certain process can be omitted

▣ Comparison between LED Package Type and LED COB Module

Heat Sink

Metal or FR4 PCB

Heat Sink

Metal or FR4 PCB

SMD

HEAT SINK

HEAT SINK

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1. KOREASUNLED’s Various Kinds of COB module

1) KOREASUNLED’s COB modules for LED TUBE , LED Panel , LED High Bay

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1. Various Kinds of KOREASUNLED’s products using COB

Products Model COB used Picture

LED BULB SBL-017A

LED TUBE SFL-0221

LED High-Bay SFD-0800

LED Flood Light SFD-2509

SFD-4009

LED Street Light

LED Guard Light

SSL-0900

SGL-0800

LED Plant Panel SPL-H367

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▣ LED application fields

AutomotiveBack light/Key pad Traffic signal

Display/Sign IlluminationWhite LEDLamp

1. Broad Application field of LED

= The End =