III. MEMS Projection Helvetica 20 Displays

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1 Helvetica 26 Helvetica 22 III. MEMS Projection Displays Micro Mirror Projection - Texas Instruments DMD - Daewoo Elec. AMA Grating Light Valve - Silicon Light Machines Image Projection Color Synthesis Pixel Addressing 46

2 History of Micromechanical Helvetica 26 Projection Display (1) Westinghouse Helvetica Mirror-Matrix 22 Device Surface micromachined Built on SOS (Sapphire) Addressed by electron beam Deflect up to 4 Contrast ratio: 10 to 1 Difficulty in HNA release etch Limited resolution in electron beam R. N. Thomas, "The mirror matrix tube: A novel light valve for projection display," IEEE T-ED, 22, 765 (1975) 47

3 History of Micromechanical Helvetica 26 Projection Display (2) IBM Cantilever Helvetica Light Modulator 22 Array ~ +/- 1 deg. K. E. Petersen, "Micromechanical Light Modulator Array Fabricated on Silicon," Appl. Phys. Lett. vol. 31, 521 (1977). 48

4 History of Micromechanical Helvetica 26 Projection Display (3) Texas Instruments, Helvetica Deformable 22 Mirror Device (DMD) 128 x 128 Deformable Mirrors Mirror Size 51 m x 51 m DRAM like operation (hold & refresh) response 25 s hold 200 ms Addressed by embedded MOS Transistors Air gap 620 nm Mirror fill factor 32 % L. J. Hornbeck, "128 x 128 Deformable Mirror Device," IEEE Trans. ED (1983). 49

5 Prototypes Helvetica of TI 26DMD Helvetica 22 L. J. Hornbeck,"Deformable Mirror Spatial Light Modulator, " Proc. SPIE vol (1989) 50

6 MEMS Projection Helvetica 26 Display (1) Helvetica 22 Digital Micromirror Helvetica Device 20 Texas Instruments References [1] Graphic Images --> [2] Up-to-date --> P. F. Van Kessel, L.J. Hornbeck, R. E. Meier,M. R. Douglass, "A MEMS-based projection display," Proc. IEEE, vol.86, (1998) [3] Up-to-date --> L. J. Hornbeck, "Digital Light Processing for High Brightness, High Resolution Applications," Proc. SPIE vol (Electronic Imaging EI'97, Feb , 1997, San Jose, CA). [4] MEMS & DMD ---> Gregory A. Magel, "Micromachining in Optics," com/dlp/resources/whitepapers/pdf/micro.pdf [5] History overview ---> L. J. Hornbeck,"From cathode rays to digital micromirrors: A history of electronic projection display technology," whitepapers/pdf/titj03.pdf 51

7 Good Example Helvetica of "Quantity 26 Changes Quality" Texas Helvetica Instruments 22 Digital Mirror Device (DMD) for Digital Light Processing (DLP) 52

8 Principle Helvetica of Image 26 Projection Electrostatic On-Off Helvetica Control 22 of Mirror Array 53

9 Advantage of Helvetica MEMS Projection 26 Display Compared with Helvetica Liquid 22 Crystal Display + High Contrast and High Brightness due to Fill Factor ~ 1 + Controlled both in digital mode (PWM) and analog mode (SLM) + Small size + New market for Portable Projector and Large Screen TV Monitors LCD Image DLP Image PWM: Pulse Width Modulation SLM: Spatial Light Modulation 54

10 Structure Helvetica of DMD 26 Aluminum Mirror Helvetica on Addressing 22 CMOS SRAM 55

11 Fabrication Helvetica Process 26 of DMD Al mirror ---- CMOS Helvetica Process compatible 22 Photoresist sacrificial layer --- removed by plasma etching DMD on CMOS SRAM by 6 mask process 56

12 Electrostatic Helvetica Operation 26 Helvetica 22 Mechanical Restoring Torque Landing Electrode Driving Electrodes GND Electrostatic Torque Angle Angle Angle Angle Angle 57

13 Mechanical Helvetica Characteristics 26 of DMD Temporal Response Helvetica 22 to Step Voltage Resonant Frequency ~ 50 khz Step Response ~ 12 s CMOS 5 V Drive 450 Billion Contacts 58

14 Number Helvetica of Pixels 26 Helvetica 22 SVGA XGA SXGA 848 x x x , ,432 1,310,720 Typical Notebook PC LCD 59

15 Addressing Helvetica Architecture 26 CMOS SRAM Helvetica for Electrostatic 22 Operation CMOS 5 V Drive 60

16 Brightness Helvetica Control 26 Pulse Width Modulation Helvetica for 22Gray Scale Image ON OFF Dark Similar to the principle of LCD display Bright Time 61

17 Color Synthesis Helvetica by One 26 DMD Chip Helvetica 22 62

18 Color Synthesis Helvetica by Two 26 DMD Chips Helvetica 22 63

19 Color Synthesis Helvetica by Three 26 DMD Chips Helvetica 22 64

20 Schematic of Helvetica Three-DMD 26 Projector Can you figure Helvetica out how 22it works?... 65