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PHOSPHOR CONVERTED WHITE LED

PHOSPHOR CONVERTED WHITE LED. Contents. 1. White LED 2. Phosphor Converted White LED 3. Characteristics of Phosphors for White LED application 4. Phosphors Claimed, Studied and Used in LED Application 5. Phosphor Mounting A. Fabrication B. LED Efficiency C. Epi Growth

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PHOSPHOR CONVERTED WHITE LED

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  1. PHOSPHOR CONVERTED WHITE LED

  2. Contents 1. White LED 2. Phosphor Converted White LED 3. Characteristics of Phosphors for White LED application 4. Phosphors Claimed, Studied and Used in LED Application 5. Phosphor Mounting A. Fabrication B. LED Efficiency C. Epi Growth D. Extraction Efficiency E. Junction F. LED Basics G. LED Business H. LED Applications

  3. 1. White LED : Introduction LED 형광체 G  B (A) multi chip (single color LED) R (1) R, G, B LED 백색 G B Advantage (vs. CCFL) (B) R single chip (multi color LED) * Increased Color Gamut * Mechanical Stability * Fast switching Time   (A) Y B Y Ph (2)  B LED + Phosphor (B) R/G R, G Ph B R/G/B (3) UV UV LED + Phosphor

  4. 1. White LED : Characteristics LCD BLU color stability chip degradation LED 형광체 color gamut Advantages vs. Disadvantages  (1-A) * Adv: adjustable white point sequential color potential Dis : complexity in control circuit large mixing & compensation area efficiency of green LED (e.g.) Lumileds (LCD TV, monitor) * Adv: adjustable white point sequential color potential small mixing & compensation area Dis : complexity in control circuit complexity in chip design efficiency of green LED (e.g.) Osram opto., Nichia (LCD monitor) * Adv : simple control circuit small mixing compensation area Dis : fixed white point no sequential color potential (e.g.) 2-A : small sized BLU, flash lamp 2-B : CRI  for lighting, BLU for LCD TV ? 3 : development of near UV LED G excellent (~100%) excellent (~100%) good (~70%) very good (~90%) excellent (~100%) good good very good very good excellent 2G/1B/1R B R 백색 (1-B) G B R (2-A) Y B  (2-B) R/G B (3) ? R/G/B UV

  5. 1. White LED : Application (Backlight) LCD Backlight – Lumileds

  6. 1. White LED : Application (Backlight)  LCD Backlight – Lumileds

  7. 1. White LED : Application (Backlight)  LCD Backlight – presented at 2004 FPD (Japan) by HannStar (Taiwan) Using R, G, B LED Using White LED What kind of white LED?

  8. 1. White LED : Application (Backlight)  Mixing & Compensation Area Osram Opto, Nichia G B R Lumileds G B R

  9. 2. Phosphor Converted White LED : Need for Phosphors (I) * Efficiency of Green LED > B LED * G Phosphor (530nm) = 60% * 70% * 87% = ~ 37 % G LED = ~ 20 %  2 G LED + 1 B LED + 1 R LED Why? Transition to indirect band-gap material at above 0.53 of Al Why? difficult to obtain high quality InGaN epi- layer due to re-evaporation of In from growth surface  wider FWHM of green LED and the subsequent low color purity

  10. 2. Phosphor Converted White LED : Need for Phosphors (I) * White를 위해 3.0 lm, 5.7 lm, 0.57 lm 이 필요함 * R LED의 경우 85%, B LED의 경우 65 %만 사용 * current ratio를 작게 가져가거나 or 2 G LED + 1 B, R LED * HB LED의 경우 I와 T에 따른 보상이 필요함

  11. 2. Phosphor Converted White LED : Need for Phosphors (II) * efficiency vs. temperature * efficiency vs. time (life time) - same effect for PC white LED - less effect for PC white LED optical feedback

  12. 2. Phosphor Converted White LED : Need for Phosphors (II)

  13. 3. Characteristics of Phosphors for White LED Application Parameters  Excitation WL  Absorption efficiency (Reflection)  Quantum efficiency  Stock shift  Luminance (Peak WL: Eye factor)  Emission color (Peak WL, FWHM)  Temperature dependency (Peak WL, Luminance)  Particle size  Scattering Particle  Surface modification  Refractive index (Phosphor, Encapsulation material)  Gravity (Phosphor, Encapsulation material)  Phosphor mixing ratio (CCT, CIE, CRI, Color Gamut) & thickness  Structure of phosphor coating layer  Environment friendly  Phosphor degradation  Radiation damage of encapsulation (epoxy or silicone) Illumination vs. backlight

  14. lm/W W/nm Br = 680  Y() P() d X =  X() P() d u = 4X / (X + 15Y + 3Z) x = X / (X + Y + Z) v = 6Y / (X + 15Y + 3Z) Y =  Y() P() d y = Y / (X + Y + Z) for uniform chromaticity coordinates (color difference between two point) Z =  Z() P() d 3. Characteristics of Phosphors for White LED Application  Basics of Radiometry and Photometry 1931 CIE X, Y, Z color matching function 555 nm  Photometry unit : lm, cd = lm/sr, lux = lm/m2, nit = cd/m2

  15. 3. Characteristics of Phosphors for White LED Application  Basics of Radiometry and Photometry Consider one photon at each wavelength, Br (Y) cie x cie y

  16. 3. Characteristics of Phosphors for White LED Application  Basics of Radiometry and Photometry : CIE (x,y) chromaticity diagram all the colors perceivable by human eyes 520 nm 530 nm 540 nm 510 nm 550 nm 560 nm 570 nm 500 nm 580 nm 590 nm 600 nm 610 nm 620 nm 490 nm 480 nm 470 nm 460 nm

  17. 3. Characteristics of Phosphors for White LED Application  Basics of Radiometry and Photometry : CIE (x,y) chromaticity diagram

  18. same cct v u y x 3. Characteristics of Phosphors for White LED Application  Basics of Radiometry and Photometry : CCT standard light sources (specific emission spectrum)  Different body color (R() S())  same cct, different (x,y)

  19. 3. Characteristics of Phosphors for White LED Application  Basics of Radiometry and Photometry : Color Gamut (Backlight) current ratio, phosphor ratio for white NTSC : (0.14,0.08), (0.21,0.71), (0.67,0.33)

  20. 3. Characteristics of Phosphors for White LED Application  Basics of Radiometry and Photometry : CRI (Illumination) general color rendering index, Ra color difference of each sample objects (u,v) between under standard light source and tested light source Ri = 100 – 4.6 Ei Ei =100 { [(uk,i– uk)-(uoi-uo)]2 + [(vk,i– vk)-(voi-vo)]2 }1/2  Ra = (R1 + ~ R5 ~ + R8) / 8

  21. 3. Characteristics of Phosphors for White LED Application  Basics of Radiometry and Photometry : Color Purity color purity = a / (a+ b) one of problems

  22. 3. Characteristics of Phosphors for White LED Application  Basics of Radiometry and Photometry : Color Mixing (di-chromatic)

  23. 3. Characteristics of Phosphors for White LED Application  Basics of Radiometry and Photometry : Color Mixing (tri-chromatic)

  24. 3. Characteristics of Phosphors for White LED Application  Basics of Radiometry and Photometry : values from measured spectrum

  25. 3. Characteristics of Phosphors for White LED Application  Basics of Radiometry and Photometry : values from simulated spectrum

  26. 3. Characteristics of Phosphors for White LED Application  Color Gamut CCFL

  27. 3. Characteristics of Phosphors for White LED Application  Color Gamut R, G, B LED

  28. 3. Characteristics of Phosphors for White LED Application  Color Gamut B LED + Y Ph

  29. 3. Characteristics of Phosphors for White LED Application  Color Gamut B LED + R,G Ph

  30. 3. Characteristics of Phosphors for White LED Application  Color Gamut

  31. 4. Phosphors Claimed, Studied and Used in LED Application * What & How? - B light : converted to Yellow light by Phosphor converted to Red and Green (Yellow) light by Phosphor - UV light : converted to Red, Green, Blue light by Phosphor * Key Factor for Producing White light? - for General Lighting : color rendering index - for BLU : color gamut * Who (patent)? Phosphors for PC- White LED - Nichia - Osram Opto.(Siemens, Osram Lighting) - Lumileds (Philips) - Gelcore (GE) - Toyoda - LBG (LWB) - Toshiba - Matsushita

  32. 4. Phosphors Claimed, Studied and Used in LED Application • YAl5O12:Ce3+,Sm3+ • TbAl5O12:Ce3+ (Ba,Sr,Ca)2SiO4:Eu2+ * Commercially used Yellow Phosphorfor B LED - Nichia : YAG:Ce - Osram Opto : TAG:Ce - Lumileds (Philips) : YAG:Ce (Nichia), YAG:Ce,Pr - Gelcore (GE) : ? - Cree : YAG:Ce (Nichia) - Toyoda : YAG:Ce (Nichia) - Rohm, Lite-on, Everlight, Vishay : TAG:Ce (Osram) - Citizen : YAG:Ce (Nichia) - Stanley : YAG:Ce (?) - Samsung E.M. : TAG:Ce (Osram) - Seoul S.C. : Ortho-silicate:Eu (LWB,Toyoda) - Matsushita : ? * Commercially used Red, Green Phosphor for B LED - Strong Candidate : CaS:Eu, STG:Eu - Degradation of Sulfide Phosphors ? Luminance ? * Commercially used Phosphors for UV LED - Toyoda : ZnS:Cu,Al / Halo-phosphate:Eu / LOS:Eu

  33. 4. Phosphors Claimed, Studied and Used in LED Application Licensing : PC - White LED Rohm Samsung E.M. Citizen Lumileds Cree Osram Nichia Liteon Toshiba Everlight Toyoda UV LED + Phosphors * Seoul S.C : Phosphor from LWG(Toyoda) + B LED chip from Cree

  34. 4. Phosphors Claimed, Studied and Used in LED Application Matsushita 1. Publication : EP1447853 (2004, 8) 2. Priority : 2001, 10 3. * 1항 : UV LED (350~410nm) + B Ph (400~500nm) + G Ph (500~550nm) + R Ph(600~660nm) + Y Ph (550~600nm) * 2~8항 : Y Ph : (Sr1-a1-b1-xBaa1Cab1Eux)2SiO4, 0  a1 0.3, 0  b1 0.6, 0 ≺ x ≺ 1 B Ph : (M1-xEux)10(PO4)6Cl2, M = Ba, Sr, Ca, Mg (M1-xEux)(N1-yMny)Al10O17, M = Ba, Sr, Ca & N = Mg, Zn & 0  y  0.05 G Ph : (M1-xEux)(N1-yMny)Al10O17, M = Ba, Sr, Ca & N = Mg, Zn & 0.05  y  1 (M1-xEux)2SiO4, M = Ba, Sr, Ca, Mg R Ph : (Ln1-xEux)O2S, Ln = Sc, Y, La, Gd

  35. 4. Phosphors Claimed, Studied and Used in LED Application LBG (LBW) 1. Publication : WO 02/054502 (2002, 7) (KR공개 2003-74641) 2. Priority : 2000, 12 3. * 1항 : UV or B LED + (2-x-y)SrO x(BauCav)O (1-a-b-c-d)SiO2, aP2O5, bAl2O3, cB2O3, dGeO2 : yEu2+ * 형광체를 강조하여 1항에서 claim * B Ph : alkaline earth aluminates:Eu2+, Mn2+ R Ph : Y(V, P, Si)O4:Eu2+, Y2O2S:Eu3+, Bi3+, alkaline earth magnesium disilicate (M3-x-yMgSi2O8:Eu2+, Mn2+) 1. Publication : WO 02/054503 (2002, 7) with Toyota Gosei (KR공개 2003-91951) 2. Priority : 2000, 12 3. * 1항 : LED + Ph로 이루어진 발광장치에서 형광체는 ortho-silicate * 3항(종) : ortho-silicate를 규정함. (2-x-y)SrO x(BauCav)O (1-a-b-c-d)SiO2, aP2O5, bAl2O3, cB2O3, dGeO2 : yEu2+ * LED + Ph”로 이루어진 발광장치상의 구조 등에 대한 claim이 주를 이룸.

  36. 4. Phosphors Claimed, Studied and Used in LED Application Toyoda Gosei 1. Publication : KR1997-0030949 (1997, 6) 2. Priority : 1995, 11 3. * 1항 : Phosphor + UV * Reject : 재심사 청구 1. Patent : US6791116 (2004, 9) with Matsushita 2. Priority : 2002, 4 3. * Scattering material과 phosphor를 함유한 diode 발광장치 1. Publication : JP2004-127988 (2004, 4) (WO 04/032251) 2. Priority : 2002, 9 3. * UV or Blue LED + Y, R, G, B Phosphor * Y Ph = (2-x-y)BaO x(SruCav)O (1-a-b-c-d)SiO2, aP2O5, bAl2O3, cB2O3, dGeO2, : Eu2+

  37. 4. Phosphors Claimed, Studied and Used in LED Application Toyoda / Toshiba * Near UV LED + R, G, B Ph ?

  38. 4. Phosphors Claimed, Studied and Used in LED Application Toshiba 1. Publication : JP2004-103443 (2004, 4) 2. Priority : 2002, 9 3. * B LED + Y, R Phosphors 1. Publication : JP2003-318447 (2003, 11) 2. Priority : 2002, 4 3. * LED (400~500 nm) + Ph 1 (500~600 nm) + Ph 2 (600~700 nm) 1. Publication : JP1999-246857 (1999, 9) 2. Priority : 1998, 2 3. * UV LED + R Ph * 1항 : R Ph = (La1–x–yEuxSmy)2O2S, 0.01  x 0.15, 0.0001  y  0.03 * 형광체를 강조하여 1항에서 claim * 5항 : La 대신 Y or Gd를 일부 함유 KASEI?

  39. 4. Phosphors Claimed, Studied and Used in LED Application Toshiba 1. Publication : JP2000-183408 (2000, 6) 2. Priority : 1998, 12 3. * UV LED + B Ph + O Ph (excited by B Ph) * B Ph = M10(PO4)6Cl2:Eu2+ * O Ph = (Y,Gd)3Al5O12:Ce3+ 1. Publication : JP2002-203991 (2002, 7) 2. Priority : 1997, 9 3. * UV LED + R, G, B Phosphors

  40. 4. Phosphors Claimed, Studied and Used in LED Application 1. Publication : JP1996-36835 (1998, 2) 2. Priority : 1996, 7 3. * 형광체 특허임 * (Y 1-p-q-r GdpCeqSmr)3(Al1-sGas)5O12, 0  p 0.8, 0.003  q  0.2, 0.003  r  0.08, 0  s  1 Nichia 1. Patent : US5998925 (1999, 12) (Family : US6069440, US6608332, US6614179, JP2927279) 2. Priority : 1996, 7 3. * 1항(독) : Garnet material, A3B5O12:Ce, A = Y, Lu, Sc, La, Gd, Sm & B = Al, Ga, In * 2항 :Y와 Al을 함유하는 yttrium aluminum garnet material * 3항 : (Re1-rSmr)3(Al1-sGas)5O12:Ce, 0  r 1, 0  s  1, Re = Y, Gd 1. Patent : US6069440 (2000, 5) 2. Priority : 1996, 7 3. * 1항(독) : Blue light 일부를 흡수할 수 있는 형광체 1. Patent : US6614179 (2003, 9) 2. Priority : 1996, 7 3. * 1항(독) : (Re1-rSmr)3(Al1-sGas)5O12:Ce, 0  r 1, 0  s  1, Re = Y, Gd

  41. 4. Phosphors Claimed, Studied and Used in LED Application Nichia 1. Publication : US2004-135504 (2004,7) 2. Priority : 2002, 3 3. * 형광체 자체가 1항이며, 연색성 증가위해 Red 성분의 보충을 갖는 형광체 조성 LxMyN(2/3x + 4/3y):R, LxMyOzN(2/3x + 4/3y – 2/3z):R where, L = Mg, Ca, Sr, Ba, Zn & M = Si (essential), C, Ge & R = Eu2+ (essential), RE * LED : below 500 nm Ph : 520 ~ 780 nm 1. Patent : JP3419280 (2003, 4) 2. Priority : 1996, 11 3. * 365 nm  LED 400 nm, Red Ph * aMgO bLi2O Sb2O3 : cMn dMgO eTiO2 : fMn jCaO kMO TiO2 : iPr, M = Zn, Mg, Sr, Ba 1. Publication : JP1998-112557 (1998, 4) 2. Priority : 1996, 10 3. * LED + (M,Eu,Q)O n(Al1-m,Bm)2O3, M = Mg, Ca, Sr, Ba, Zn & 0 m 0.5 & 0.5 n10 Q (co-activator) = Mn, Zr, Nb,… etc.

  42. 4. Phosphors Claimed, Studied and Used in LED Application Nichia 1. Publication : JP1999-046019 (1999,2) 2. Priority : 1997, 7 3. * Phosphor mounting by Ink jet method JP : 2998696 (1999), 3036465 (2000), 2900928 (1999), 3065258 (2000) JP Publication : 1998-154830, 1998-228249, 1998-233533, 1998-247750, 1999-199781

  43. 4. Phosphors Claimed, Studied and Used in LED Application Nichia * YAG : (Y 1-p-q-r GdpCeqSmr)3(Al1-sGas)5O12 온도 특성 향상 Gd Gd

  44. 4. Phosphors Claimed, Studied and Used in LED Application Nichia * YAG : (Y 1-p-q GdpCeq)3(Al1-sGas)5O12

  45. 4. Phosphors Claimed, Studied and Used in LED Application Nichia * YAG : (Y 1-p-q GdpCeq)3(Al1-sGas)5O12

  46. 4. Phosphors Claimed, Studied and Used in LED Application Nichia When using YAG, low Ra at low CCT For “High Ra” or “warm white” : new red phosphor ! (655 nm)

  47. 4. Phosphors Claimed, Studied and Used in LED Application Nichia High CRI – daylight white LED, using shorter YAG and red phosphor 3.2 V / 20 mA 1.8 lm / 28.3 lm/W 4600 K (0.357/0.355) Ra = 76.2 3.3 V / 20 mA 1.67 lm / 28.3 lm/W 4670 K (0.355/0.361) Ra = 87.7

  48. 4. Phosphors Claimed, Studied and Used in LED Application Nichia High efficacy or CRI – warm white LED, using YAG and red phosphor 3.22 V / 20 mA 1.49 lm / 23.1 lm/W 2810 K (0.451/0.408) Ra = 72.5 3.24 V / 20 mA 1.23 lm / 18.9 lm/W 2830 K (0.449/0.408) Ra = 87.5

  49. 4. Phosphors Claimed, Studied and Used in LED Application Light for 21C : Stanley/Mitsubishi/Kasei/Yamaguch Univ. * Near UV LED + R, G, B Ph

  50. 4. Phosphors Claimed, Studied and Used in LED Application Light for 21C : Stanley/Mitsubishi/Kasei/Yamaguch Univ. * Near UV LED + R, G, B Ph

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