LED 측정장비소개 광전자정밀 2006. 10. www.optel-precision.com
목차 1. LED 정의 2. LED 원리 3. LED 구조 4. LED 제조공정 5. LED 응용분야및시장, 시장전망 6. 전기특성측정법및장비 7. 광특성측정법및장비 8. 열특성측정법및장비 9. 측정장비의발전방향 10. 광전자정밀 ( 주 ) 소개 2
LED(Light Emitting Diode) 소개 LED 란? 발광다이오드의약자로화합물반도체의특성을이용해전기신호를적외선또는빛으로변환시켜신호를보내고받는데사용되는반도체소자를말하며전자제품류와가정용가전제품, 리모컨, 자동차, 전광판, 각종자동화기기, 신호등, 조명기구등에사용된다. LED 의특징 1. 발광효율이높고저전류에서고출력을얻을수있다 2. 응답속도가빠르고펄스동작고주파에의한변조가가능하다 3. 광출력을전류제어로용이하게변화시킬수있다 4. 소형경량, 장수명이며, 소비전력이적다. 5. 작동온도범위가 -200 ~200 로극단적인곳에사용가능 6. 다양한색상연출가능 7. 수은을사용하지않는환경친화적광원 3
LED 원리 LED 전극에순방향전압 (P 층 :+, N 층 -) 를가하면전도대의전자가가전자대의정공과재결합을위하여천이될때그에너지만큼빛이나, 전파로방출된다. Eg 는반도체결정의재료및농도등에의하여차이를가짐에따라방출주파수나파장이달라진다. 4
LED 구조 5
LED 제조공정 Chip 제조공정 수입검사전처리증착전극형성 전극형성검사 개별화 Etching 외관선별 특성검사 세척 표면증착 PR Coating 메탈에칭 외관검사 보호코팅 메사에칭 전 사 작업성 Etching 이면증착 노 광 PR 제거 Rp-p Dicing 보호코팅제거 외관선별 전기적특성 건조 현 상 검 사 전반검사 Expaning 검 사 QRA 확인 Sintering 검 사 입 고 Package 제조공정 6
LED 응용분야및시장 Chip & Lamp 다양한영역에서상품화 Present 2005-2006 2007-2010 Module & System Back light LCD TV BL Automotive White LED Lamp Traffic signal Display/Sign Architectural Illumination ( 한국광기술원제공 ) 7
LED 발전방향및시장전망 <2005 년 LED 표준화포럼 > 8
LED s Properties and Measurement 1. Electrical properties 2. Optical Power(Quantity) properties 3. Optical Spectral properties 4. Thermal properties 9
Electrical properties of LEDs DC Test V f : Forward voltage I f : Forward current V r : Reverse voltage I r : Reverse current P : Power dissipation ( P = V f * I f ) Thyristor Test Response time Test T r : rise time T f : fall time Surge current Test ESD C p : Capacitance 10
DC Test Current V f, I f, V r, I r V r I f I r V f thyristor Voltage Power Dissipation P = V f * I f Thyristor Test Sweep Curve Some Points I, V I f Sourcing 20μA V f Low bound 0.50V V f High Bound 0.95V 100μA 0.70V 1.05V Tester Feedback DUT 200μA 1mA 0.85V 0.95V 1.10V 1.15V 2mA 1.00V 1.15V <Kelvin Probing Method> 11
Response time Test Definition Driving circuit 90% 10% 5V C1 5V R2 T r T f T r : rise time, T f : fall time 74AC T08 R1 Surge Current Test : ESD 1. Measure 1 I r (Reverse Current) 2. Load Surge Current( high voltage and small current pulse) 3. Measure 2 I r (Reverse Current) 4. Compare 2 I r with 1 I r 12
측정장비 DC 측정기 Keithley ESD 인가장비 NoiseKen Capacitance 측정기 Hioki 13
Optical power properties PHOTOMETRY UNIT SYMBOL RADIOMETRY UNIT SYMBOL Luminous Flux ( 광선속 ) lm ф V Radiant Flux ( 복사선속 ) W ф e Luminous Intensity ( 광도 ) lm/sr=cd I V Radiant Intensity ( 복사도 ) W/sr I e Luminance ( 광휘도 ) cd/m 2 = nit L V Radiance ( 복사휘도 ) W/sr*m 2 L e Luminous View Angle ( 광지향각 ) deg θ Radiant View Angle ( 복사지향각 ) deg θ 14
Equation I( λ) [ W / sr nm] for Barrel Φ( λ) [ W / nm] for Integrating Sphere spectrum (W/nm) 50 40 30 20 λe I V = K I( λ ) V( λ) dλ λs 10 0 350 450 550 650 750 850 wavelength (nm) Luminous Efficacy(lm/W) ΦV KV = V I f f Radiant Efficacy(W/W) Φe Ke = V I f f Radiant Intensity(W/sr) I e = λ E λ S I(λ) dλ Luminous Intensity(cd) I V Radiant Flux(W) Φ Φ e V = K λ E = Φ (λ) dλ λ S Luminous Flux(lm) = K λ λ λ E λ E S S I( λ ) V( λ) dλ Φ( λ ) V( λ) dλ 15
Inverse square law I E 2 2 I E r r E : Irradiance or Illuminance I : Intensity r : distance between light source and detector 16
Area of radiation LED is not a point light source 17
CIE Average Intensity CIE Standard Condition A Circular aperture of area : 100mm 2 (diameter : 11.3mm) Distance : 316 mm, solid angle : 0.001 sr CIE Standard Condition B Circular aperture of area : 100mm 2 (diameter : 11.3mm) Distance : 100 mm, solid angle : 0.01 sr 18
Geometric sensitivity The small tilt of geometric axis will make the measured intensity to have large different value. The precision barrel and adapters are needed to align LEDs. Max : 4000mcd Max : 8000mcd 19
Photometer s photopic filter V(λ) is not the same as CIE s Relative spectral response of a typical commercial photometer 20
Spectral mismatch errors Error for the blue LED: - 20 % Error for the red LED : +15 % 21
Recommendation 22
Temporal dependence Pulse Mode Current Driving is recommended period current width Time Optical efficiency is also improved 23
Goniometer Φ = A E 2 π 2 ( θ φ ) da = r E ( θ, φ ) π, sin θ d θ d φ φ = 0 θ = 0 24
Integrating sphere CIE Recomendation 1) Size of integrating sphere r > 15 cm 2) Auxiliary lamp Self-absorption of the test LED 3) Standard LED Photometer is used and the reflection coefficient of integrating sphere is changing 4) Test LED is positioned at the center Backward emission is excluded and side way emission is partially lost E d = Φ ( 1 m) 4πr 2 Φ : Total flux of LED E d : Iluminance or Irradiance at detector m : Reflection coefficient of sphere r : Radius of integrating sphere 25
측정장비 Giga Hertz Optik Labsphere Optel Precision LMT 26
luminance Angle of measurement Imaging plane detector lens aperture Light source f 2 2 τπl(1 ) τπl ( D/ f ) E = = s = τωl 2 2 4 (1 + m) 4F L : luminance or radiance of light source f : focal length of lens D : effective diameter of lens s : distance between light source and lens m : magnification ratio Ω : solid angle with respect to aperture τ : transmission ratio of lens 27
측정장비 Minolta Topcon 28
Spatial Intensity distribution View Angle describes the spatial intensity distribution and is the difference between the angles corresponding to 50% of the maximum intensity. θ 0.5 = θ R 0.5 - θl 0.5 29
배광측정기 웨이퍼 단품패키지 모듈 30
배광측정기사양 SPECIFICATIONS Automated horizontal range(θ) A/D Transfer Resolution Minimum horizontal angle resolution Minimum axial range(φ) Minimum axial angle resolution Computer interface Linear positioning stage travel range Dimensions Enclosure Scan time Range of wavelength Sensor Sensing hole size Include power supply Power requirements Maximum Sample Dimension Maximum Sample Weight -135 ~ +135 16 Bit 0.1 0 ~ 360 0.1 RS232 35cm 800mmX800mmX1300mm lightproof enclosure Within 1 Minutes UV, IR Selectable Si Photo diode with V(λ) Filter 100 mm 2 0~200 ma 220V, 50/60Hz 1000mm 30 Kg 31
Spectral properties of LEDs UNIT SYMBOL UNIT SYMBOL Peak Wavelength ( 최고파장 ) λ p Color coordinate ( 색좌표 ) x, y Full Width Half Max ( 반측폭 ) FWHM Dominant Wavelength ( 주파장 ) λ d Centroid Wavelength ( 중심파장 ) λ c Purity ( 색순도 ) Center Wavelength ( 중간파장 ) λ m Color Rendering Index ( 연색지수 ) R a Correlated Color Temperature ( 상관색온도 ) T c 32
Wavelength Peak Wavelength λ p : Wavelength at maximum intensity Band Width FWHM : λ 0.5 = λ 0.5 - λ 0.5 Center Wavelength λ.0.5m = (λ 0.5 + λ 0.5 ) / 2 Centroid Wavelength λ c λ 2 2 = λ I( λ) dλ λ 1 λ λ 1 I( λ) dλ 33
34 = 830 360 ) ( ) ( λ λ λ d x I k X = 830 360 ) ( ) ( λ λ λ d y I k Y = 830 360 ) ( ) ( λ λ λ d z I k Z Z Y X X x + + = Z Y X Y y + + = Tristimulus Values CIE 1931 Chromaticity Diagram CIE 1976 Chromaticity Diagram Z Y X X u 3 15 4 + + = Z Y X Y v 3 15 9 + + = CIE 1931 CIE 1976 Color coordinates
Dominant Wavelength Dominant Wavelength Wavelength of the monochromatic stimulus that matches the color stimulus considered Purity (1/3, 1/3) P e = y yn y y d n or P e = x xn x x d n 35
36 Correlated Color Temperature (CCT) ( ) ( ) { } j T j j T j U U m V V d = 1 1 1 1 1 1 + = j j j j j j c T T d d d T T U T, V T : color coordinates 1 2 0 5 2 1, ] 1 ) / )[exp( / ( ), ( Ω = T n c n c T L e λ λ λ λ λ Planck s law Linear interpolation Color Temperature
Color Rendering Index Color Rendering Index (CRI) CRI is a unit of measure that defines how well colors are rendered by different illumination conditions in comparison to a standard (i.e. a thermal radiator or daylight). When CRI is calculated, it can be rated on a scale from 0-100. On this scale, a CRI of 100 would represent that all color samples illuminated by a light source in question, would appear to have the same color as those same samples illuminated by a reference source. 37
Color Rendering Index CIE No.13.3(TC-3.2) 1995 1. Reference source is a perfect radiation source (CIE combined source) that has the same color temperature with the test source. 2. 15 Reference reflectance samples, which are provided by CIE, have the known spectral reflectances. 3. Calculate the color coordinates from resulted spectrums that are the product of reference source and reference samples, the product of test source and reference samples. 4. Calculate the distance between the reflected test and the reflected reference color coordinates 5. Calculate average CRI and special CRI. Reflectivity 0.75 0.70 0.65 0.60 0.55 0.50 0.45 0.40 0.35 0.30 0.25 0.20 0.15 0.10 0.05 425nm 475nm 525nm 575nm 625nm Wavelength [ 시험색의분광반사율 ] R1 R2 R3 R4 R5 R6 R7 R8 38
Spatial spectrum distribution 39
Influence of temperature on radiation Slight change in the shape of the distribution, whole distribution will shift significantly in the direction of longer wavelength 온도변화에따른베럴분광특성변화 상대분광복사조도 0.03 0.025 0.02 0.015 0.01 0.005 20 도 40 도 60 도 80 도 100 도 120 도 Shift of peak wavelength with temperature λp 0.1...0. 3 nm T K C 0 400 450 500 550 600 650 700 750 800-0.005 파장 40
웨이퍼레벨측정장비 양산장비 품질관리및연구용 Main 화면 Map 화면 41
단품레벨측정장비 양산용 품질관리및연구용 42
모듈레벨측정장비 다채널측정장비 조명기구측정용 43
사양 Specification Peak Wavelength Dominant Wavelength Luminous Intensity Radiant Intensity CIE Chromaticity Diagram Full With Half Max Current I I f, r Voltage V f, V r *Luminous Flux *Radiant Flux Pulse mode Sourcemeter Spectral Range Thermal Electric Controller λ P λ d I v I e C x, C y FWHM Φ v Φ e Source Measurement Range Range* Accuracy Resolution I:0~10A 350~830nm * ±0.5nm 0.3nm I:0~10A 380~780nm * ±0.5nm 0.3nm I:0~10A 10~10000mcd 10% 0.1mcd I:0~10A 0.05~100mW/sr 10% 0.1μW/sr I:0~10A 0~0.7 ±0.005 0.002 I:0~10A 1~300nm * ±0.5nm 0.3nm 0~100μA ±(0.02%+12nA) 1nA V:0~40V 100μA~1A ±(0.03%+700uA) 10μA 1A~3A ±(0.05%+1mA) 10μA 0~1V ±(0.015%+200uV) 10μV I:0~10A 1~6V ±(0.015%+1mV) 10μV 6~40V ±(0.015%+8mV) 100μV I:0~10A 0.01~100lm 10% 0.001lm I:0~10A 50μW~10W 10% 1μW Minimum Pulse width : 200μsec (source only) Channel number : 1~36, Range:1~10A (Selectable) Multi channel sensor type, monochromatic type TE Cooled sensor type, CCD, PDA sensor type UV, UV~Visible, Visible, Visible~NIR, UV~NIR, UV~IR ( Selectable ) 온도범위 : -20~120 (Resolution : ±0.1 ) (Selectable) 전원공급기, 자동온도컨트롤시스템, 수냉식냉각플레이트, PT 100 Ω 센서 44
Adapter I 45
AdapterⅡ 46
Adapter Ⅲ LED 의열을제어하기위하여설계된 Adapter. TEC를이용하여 LED Package의 PIN 및 Heat Slug부분온도를신속하고정확하게제어. 사용자의요구에따라다양한형태의 LED를측정할수있도록사용자주문방식의설계가가능. Specification Temperature range -20~150 Accuracy ±0.5 Resolution 0.1 47
Input optics Ocean optics Instrument systems International light 48
Thermal properties of LEDs Calibration Factor (K-factor) Junction Temperature (T j ) Thermal Resistance (R th ) Structure Function 49
Methods 50
Heat Transfer Path 51
Thermal Modeling 52
Definition Voltage V 1 K V 2 thermocouples Set forward current so small that the junction temperature is assumed to be close to ambient temperature. T j T a (I f = 1mA) 53 T 1 T 2 Temperature K-factor K = ( V 2 V 1 ) / ( T 2 T 1 ) Thermal Resistance Θ J-P = ( T j T p ) / ( V f I f - Φ e ) Where, V is forward voltage T is junction temperature
Steady state and Transient state Steady state Transient state 2 I f, 2 V f 2 I f 1 I f 3 I f =1mA 3 V f Measure V f at more than 1Mhz sampling rate 2 T j = K ( 3 V f - 1 V f ) + 1 T j Where 3 T j = 2 T j Θ j-p = ( 2 T j - 2 T p ) / ( 2 I f 2V f ) Junction Temperature Vs Time Time constant spectrum, Structure function(r-c network) Differential Structure function Thermal analysis for structure 54
Structure function Dynamic Temperature Measurements: Tools Providing a Look into Package and Mount Structures Andras Poppe, MicReD Ltd. and Vladimir Szekely, Budapest University of Technology and Economics Copyright c2002 ElectronicsCooling Online 55
Influence of temperature on radiation Φv(mlm) 18000 16000 Luminous Flux 14000 12000 10000 8000 6000 4000 2000 0 0 20 40 60 80 100 120 140 온도 Peak 광효율 (K=lm/W) 612 20 Peak 610 608 606 604 602 600 598 596 0 20 40 60 80 100 120 140 온도 K (lm/w) 18 16 14 12 10 8 6 4 2 0 0 20 40 60 80 100 120 140 온도 56
Influence of temperature on radiation Slight change in the shape of the distribution, whole distribution will shift significantly in the direction of longer wavelength 온도변화에따른베럴분광특성변화 상대분광복사조도 0.03 0.025 0.02 0.015 0.01 0.005 20 도 40 도 60 도 80 도 100 도 120 도 Shift of peak wavelength with temperature λp 0.1...0. 3 nm T K C 0 400 450 500 550 600 650 700 750 800-0.005 파장 57
측정장비 Optel Precision MicReD 58
Main Problems for measurement The measured values of Electrical, thermal and spectral properties are almost same among companies, but the measured values of optical power properties are very different. The reasons 1. Area of radiation is not a point 2. Geometric sensitivity of spatial power distribution 3. Temporal dependence 4. Photometer s photopic filter V(λ) is not the same as CIE s 5. Auxiliary lamp is not used in the integrating sphere 6. Different ambient temperature and thermal resistance 59
Current Issues for Measurement LED for illumination High optical power (more than 1W) High optical efficacy (more than 80lm/W) High color rendering index (more than 80) Low junction temperature Strong for ESD Multi chips Low price Versatile packages Measurement Sourcemeter Multi channels High electric power Pulse sourcing Spectrometer Correct cosine corrector Large integrating sphere and auxiliary lamp High dynamic range (TE cooled sensor) Thermal tester High power heat sink Steady and transient state analysis Adapter Versatile shapes Capable of controlling temperature 60
광전자정밀 ( 주 ) 소개 회사명광전자정밀 Optel Precision Co., Ltd. 설립년월 1997 년 11 월, 현재전주시첨단벤처단지內입주 사업개황광계측전문기업으로서, 현재, LED, PD, 기타일반광원등의다양한특성을측정하는 10 여가지장비를제조판매 사업목표 광계측분야최고의지식기업을지향하며, 고품질의제품을세계시장에공급함으로써고객의경쟁력을높이고고객과더불어번영한다 사업영역측정대상물 광소자 (LED, LED Module, PD, Photo Coupler, Photo TR etc.) 일반광원 (Lamp, 형광등, CCFL, 기타 ) 측정항목 광학적특성, 전기적특성, 열적특성등. 측정장비 분광분석기, 지향각측정기, Sourcemeter, 온도제어기, 기타복합제품측정용도 양산용, 품질관리용, 연구개발용 61
회사연혁 1997 년회사창립 1998 년 Spectrometer (OPC-2000) 지향각측정장치 (OPC-3000) 개발 LED Chip 외관검사장치개발 1999 년 Vision Inspection 관련특허취득정밀스캐닝스테이지및광헤드관련특허 2 건취득수광소자측정기 (OPC-4000) 개발 2000 년 Blue LED 용 Wafer Scriber 장비개발 LED Chip Counter 개발 2001 년 Blue LED 용 Wafer Breaker 개발 LPH Sorter 개발 2002 년 Rotating Analyzer Ellipsometer 개발 Spectrometer 신제품개발 (OPI-2100) PD Chip Prober 개발 LED Chip Prober 개발 2003 년 LEOS (OPI-100) 개발 2004 년 Goniophotometer (OPI-300) 개발 Optical Power Meter(OPI-400) 개발조명용 LED 측정기술표준화포럼참여 2005 년 PO on Block TesterOPI-500) 개발 PD Package Tester OPI-510) 개발 u-leos 개발 (OPI-200) LED Thermal TesterOPI-600) 개발 LED Temperature controllable Adapter (OPA- 100) 개발사업장이전 - 전주첨단벤처단지중소기업청인정벤처기업기술신용보증기금운영자금보증 2006 년광도측정클럽참여 LED 표준화컨소시엄참여 62
사업분야 LED TEST LEOS Multi-Channel LEOS IN-LINE LED TESTER GONIOPHOTOMETER GONIOMETER OPM SPECTROMETER PROBER HANDLER LED THERMAL TESTER CHIP COUNTER Temperature-Controllable Adapter LIGHT SOURCE TEST SPECTROMETER MODULE TESTER BLU TESTER PD TEST PD Tester PD Prober POB Tester 63