DARPATech 99 DARPA/MTO Bruce Gnade
High Definition Systems Objective: Develop leading-edge display technology to meet diverse, but specific, DoD needs. The goals include increased power efficiency, reduced weight and improved ruggedness, while pushing the state-of-the-art in display performance. Demonstrate DARPAfunded technology in military applications.
High Definition Systems Current emphasis for HDS program Accelerate the development of flexible, rugged displays (organic EL, zero-power reflective, selfassembled materials) Push maturing technologies to demonstration phase (FED, Color EL) Increase the demonstration of HDS supported technology (DMD, TFEL, plasma)
CLADS PROBLEM: CRT display systems used in AWACS, JSTARS and ABCCC are becoming unsupportable: Logistics Support: $208K/CRT, MTBF ~ 500 hours SOLUTION : Technology independent systemti-dmd, dpix- AMLCD, Photonics - Plasma, etc. Impact of FPD Technology: -1064 lb.. -1750 watts MTBF > 3300 hours +70% viewing area
Small Image Sources 640x480 AMEL for Land Warrior 1280 x 1024 AMLCD for Comanche DARPA, SSCOM, CECOM-NVESD, ARL, USARARL, Armstrong Labs, NAWC Kopin Corp, Planar Inc., Sarnoff Corp., Allied Signal, Thesys, UMC, MIT-LL, U of Fl, GTRI, GIT, Oregon Graduate Institute, Honeywell, Hughes, Kaiser
High Brightness Image Sources Rotocraft Avionics Systems Performance goals - 1280x1024-1650 ft-l - 80:1 contrast ratio - <1% reflectance - Viewing angle +/-30º Proposed Technologies AMLCD - Kopin Joint development program * DARPA * Comanche * Army * NVESD AMEL - Planar
Zero-Power Displays Advantages of cholesterics 1) Reflective in visible and IR 2) 2 AA batteries / year 3) Rugged plastic displays prevent breakage 4.0µm 4.5µm 5.5µm BLUE GREEN RED Pixel States BLACK ABSORBER P/2 Color Reflective Planar State Black State
Materials for Emissive Displays TFEL Phosphor Efficiency Brightness (cd/m2) Brightness (2kV, 72Hz, 30usec) Green 1.E+05 1.E+04 1.E+03 1.E+02 1.E+01 2 35 65 120 120 200 1100 4 65 120 220 200 350 1100 8 120 210 360 340 900 1100 16 210 350 550 540 1400 1100 24 350 410 700 720 2400 ZnS:Cu 1100 48 600 800 900 1050 4000 1100 80 900 1050 1050 1500 6000 1100 140 1200 1400 1400 2800 10000 1100 1 10 100 1000 Avg. Current Density (ua/cm2) Y2SiO5:Tb Gd2O2S:Tb Y3Al5O12:Tb SrGa2S4:Eu Required Brightness Normalized Luminous Eff. 1.2 1 0.8 0.6 0.4 0.2 0 SrCaGa 2 S 4 : Ce,O All with CIE y = 0.13-0.14 SrS:Ce with blue filter SrS:Ce,Ag with blue filter SrS:Cu,F with blue filter SrS:Cu,Ag
Active Matrix Backplanes on Flexible Substrates Relative Panel Eff. 1 0.8 0.6 0.4 0.2 Passive Matrix 100 cd/m 2 10 l/w in DC R col =15Ω/ R row =0.05 Ω/ 0.1 mm pixel 0.3 mm pixel Relative Panel Eff. 1 0.8 0.6 0.4 0.2 Active Matrix 100 cd/m 2 10 l/w in DC mob.=50cm 2 /Vs 0.1 mm pixel 0.3 mm pixel 0 0 200 400 600 800 No. of Row s 0 200 400 600 800 No. of Rows * Driving force for active matrix is power efficiency * Pulsed operation and low duty cycle in PM require high current * I 2 R losses can reduce PM power efficiency by 25X Provided by Jim Sturm - Princeton Univ. POEM
LLNL * Substrate = Polyester * Max. Processing Temp = 100 C *Max. Anneal Temp. = 150 C *Si Crystallization 308nm XeCl Excimer Laser I DS (Amps) Poly-Si TFTs on Plastic 10-3 µ n = 7.5 cm 2 /V-sec 10-4 10-5 V DS = 15V 10-6 10-7 10-8 10-9 V DS = 0.1V -10 10-11 10-12 10-13 10-10 0 10 20 wafer 30 7-7-96 #2 Die 40 L12 50 V GS (Volts) Transistor I-V Curves I DS (µa) 7.0 6.0 5.0 4.0 3.0 2.0 1.0 V GS = 30V V GS = 27.5V V GS = 25V 0.0 0 5 10 15 V DS (Volts) Transistor Process Flow Laser crystallized Si doped polysilicon polyester Source Al SiO 2 poly -Si SiO 2 308nm XeCl 35ns Pulse polyester polyester Gate Drain
Self Orienting, Fluidic Transport SOFT process Flow SOFT Advantages TFT process Flow 1) high performance electronics 2) technology independent 3) size independent 4) low temp. processing 5) low capital investment 6) 2x10 7 pixels/8 wafer Gate metal Glass Substrate a-si Si 3 N 4 Nitride Source Passivation Drain a-si Si 3 N 4 Glass Substrate Beckman Display Display Process
Active Matrix Organic LED Green: (Alq 3 ) Luminance: 850 nits Polysilicon Planar Systems Eastman Kodak Sarnoff Corp Princeton University Back Plane (MgAg) Polysilicon transistor OLED material Quartz Substrate
Polymer Switched Matrix Display Column Electrodes Up-Conversion Phosphor Emission Figure 2: Illustration of high brightness full color Blue polymer display using a diode array at 980 nm. Diode Laser Array Optical switches Waveguides Green Red Row Electrodes 1.) 1.) Low Low Power Power 2.) 2.) Large Large 3.) 3.) Flexible Flexible 4.) 4.) Optical Optical toolkit toolkit Energy (cm l ) 20,000 15,000 10,000 5,000 4 F 7/2 4 H 11/2 4 S 3/2 4 F 9/2 4 I 9/2 2 F 5/2 4 I 11/2 4 I 13/2 980 nm 515 nm 550 nm 650 nm 2 F 3/2 Yb 3+ Er 3+ 4 I 15/2 Ytterbium Erbium Optical IC Gemfire Up-Conversion Phosphors
Roll-to-Roll Display Processing Roll-to-Roll laser etching electrode patterning Roll-to-Roll display assembly Polaroid
Summary What do we want in displays? * Low power * Rugged * Sunlight readable * Interactive * Inexpensive