uv leds的終端新應用 leds的終端新... · 2013. 9. 11. · uv leds的終端新應用 genesis...

UV LEDs的終端新應用

Genesis Photonics, Inc. 新世紀光電R&D center 研發中心Cheng-Yen Robert Chen, Ph. D.陳正言博士2013/09/04

Outline

¤Introduction to UV applications

¤Development Status of UV LEDs

¤Photoinitiated polymerization for UV LED active packaging and waveguide devices

¤Summary

UV Spectrum Range

• UVA能透入皮膚深部，氧化黑色素物質，使皮膚黑化，增強抵抗，也會導致黑色素瘤(Melanoma)。

• UVB可促進皮膚生成維生素D，引發皮膚下血管擴張，增加血流量，造成血管亢進發紅，進而成紅斑，脫皮、甚而發炎等。

• UVC有強烈的殺菌能力，破壤細胞DNA，可造成皮膚病變，灼傷眼角膜等。

2013/9/11 GENESIS PHOTONICS All Rights Reserved. 3

X-ray UV Visible Infrared

List of UV Applications

• 230 to 400 nm: optical sensors and instrumentation• 240 to 280 nm: sterilization of surface areas and water• 250 to 405 nm: forensic and bodily fluid detection and analysis• 260 to 300 nm: DNA/RNA/protein analysis, drug discovery• 300 to 320 nm: medical light therapy• 365 to 400 nm: polymer and ink printing• 375 to 395 nm: counterfeit detection• 390 to 410 nm: superficial/cosmetic sterilization


Source: http://electronicdesign.com/energy/

•治療乾癬 (311nm)，白斑，濕疹

http://electronicdesign.com/energy/

Intensity-dependent UV applications

UV-C

UV-A


Nitride UVLEDs

6

3.1 3.2 3.3 3.4 3.5

1

2

3

4

5

6

1

2

3

4

5

6

InN

GaN

AlN

ZnO

Band

gap

Ener

gy (e

V)

Lattice Constant (Å)

Bandgap Energy vs. Lattice Constant

400nm

200nm

UV-B

AlGaInN LEDs can cover UVA, UVB and UVC spectral range

Benefit of UV LEDs• Compactness• Robustness• low cost of ownership (system level)• Environmentally-friendly composition


Nichia

Luminus Devices

GPI SemiLEDs Crystal IS

UV LED business with 43% CAGR from 2012 to 2017

Source: UV LEDs report, March 2013, Yole Dévelopement

Development Status of UV LEDs


Development of UV LEDs


Source: http://www.i-micronews.com/Upload/iLED/iLED_June2013_IR.pdf

• 1st- UVA for Printing• 2nd- UVA for Curing• 3rd- UV-B and UV-C applications

http://www.i-micronews.com/Upload/iLED/iLED_June2013_IR.pdf

Performance Improvement of UV LED @ 395nm


> 20x improvement for the last decade

600mw

250mw

330mw

UVA LED Development in GPI

2009 2010 2011 2012 2013 201450

100

150

200

250

300

350

400

450

500

550

600

650

405nm 385nm 375nm

Die : 1x1 mm2

mW : GPI PKG Lamp @ 350mA

Rad

ial f

lux

(mW

)

Year

365nm

Hot (85oC)/Cold(25oC) factor of UVA LEDs

0 20 40 60 80 100 120 140

40

50

60

70

80

90

380nm 405nm 450nm

Hot

/Col

d Fa

ctor

(%)

Current Density (A/cm2)

ü Unlike blue InGaN LEDs, UV LEDs exist higher hot/cold factor at higher operation current density.

ü May be suitable for flip-chip design.

GPI flip chips- AT LED


ü Higher power density (W/cm2)ü Better reliabilityü Better thermal conductivityü Overdrive capability

Benefits of flip chips

GPI UV flip-chip LED

• Deliver more than 2000 mW/cm2 (390nm) in working distance• Lifetime > 20000 hrs• Operate at more than 100W


Module5050: 4*4(64ea of 45mil dies)

25mm

25mm

陶瓷基板

PCB板

(Top view)

Nail Gel UVA curing System


ü Wavelength: 390 to 410nmü 45mil flip chip operated @ 700mA to 1Aü Curing time: within 30 seconds

Development of UVC LEDs


UV-C Applications

• Germicidal Disinfection• Water Purification• Surface Sterilization• Air Purification• Analytical Instrumentation, Emitters• Protein Analysis, DNA Sequencing, Drug Discovery• Forensic Analysis• Optical Sensing• Ozone Monitoring


λ

Absorption

260nm 280nm

DNA/RNA

protein

Comparison of UVC LED with Mercury lamp and Xenon lamp


Source:http://www.cisuvc.com

http://www.cisuvc.com

EQE from 10% to >50%l AlInGaP Red LED : 1988à2000 (12 years)l InGaN Blue LED : 1998à2007 (9 years)l AlInGaN DUV LED : 2012à2020 (8 years or less) ??

LED history from Red to DUV


Source: Hideki Hirayama (RIKEN) report in “LED 50 YEARS”

Evolution of UV-C LED Performance-by RIKEN, Japan

Evolution of UV-C LED Performance-by RIKEN, Japan


Source: Hideki Hirayama (RIKEN) report in “LED 50 YEARS”

A commercial UVB LED

2013/3

Al2O3

AlxGa1-xN (8μm)

AlN/AlGaN SLS

AlGaN/AlGaN SLS

AlxGa1-xN (0.3μm)

AlxGa1-xN (0.4μm)

AlN buffer (2.4 μm)

ü The epitaxial structure is quite different from InGaN blue LEDs.

ü Much larger forward voltage remain space of improvement.

120mw 90mw 13mw 1mw

EE=75% IQE X EE=15% LEE=8%

WPE=0.8%

Commercial 275nm LED performance

l (1) Dislocation reduction (IQE)Ø quality of AlN on sapphireà TD ~2~3 E8 /cm2 , (0 0 2)=190 arsec , (1 0 2)=300 arsecØ n-AlGaN Al=60% à (0 0 2)=307 arsecØ MQWà IQE > 50%

l (2) Reduction of optical loss (LEE)Ø high absorption in p-layer à p-AlGaN/AlGaN SL 60% Transmission @275nmØ low contact reflection in DUV à p-pad R=70% , n-pad R=50% @275nmØ lack of encapsulation à surface roughing & encapsulated

l Summary Ø LEE > 25% ,IQE>50% à EQE>11% , WPE>7%

EQE breakdown

Highlights of some UVC LED Performance


Company Wp IQE LEE EQE WPE

UV Craftly Co. Ltd 285nm >80% 15%14.3%(peak)>10% (normal) ---

SETI 275nm 55% >25% 11% 7%

Meijo Univ. ~365nm 29% 11.4% 3.4% 2.6%

Berlin Technical Univ. 305nm 23% 4.5% 0.5%

Crystal IS270nm260nm 70% 15%

8.2%@100mA6.5%@65mA

4.5%4.9%

(Data updated in 2012)

ü IQE depends on high quality AlxGa1-xN material & structure design.

ü LEE is very important for DUV development , including material absorption & chip reflectance process.

ü Thermal decay , burn in decay , lifetime decay also need to be considered seriously.

Brief Summary

Photoinitiated polymerization for UV LED active packaging and waveguide devices


Blue LED active packing method with photosensitive polymerization


Ref: 17 March 2008 / Vol. 16, No. 6 / OPTICS EXPRESS, 3680

An optical curing process

Chain reaction of photo-induced polymerization


GPI collaboration with National Taiwan University

Simulation of UV propagation


Simulation Results


Constant LED power Constant exposure time


Experimental results

32

GPI collaboration with National Taiwan University

ü Suitable for flip chips (no wire bonding)ü mm-scale optical lensü Control of LED radiation pattern through UV exposure conditions

UV-induced photo-initiated polymerization for self-written waveguides


X-type waveguide

Y-type waveguide

Simulation Results

ü Combining with automation control, similar to 3D printing technology, complex optical coupling devices could be fabricated.

Summary

• With outstanding properties, UV LEDs provides versatile application possibilities.

• Applications of UVA LEDs in printing and curing industry are increasing firmly.

• The population of UVB/UVC LED applications depends strongly on the performance improvement of UV LEDs.

• Novel applications of UV LEDs are expected to come along with LED technology breakthrough.


uv leds的終端新應用 leds的終端新... · 2013. 9. 11. · uv leds的終端新應用 genesis...

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