1. Eric Dacquay Brian Freedman Lisa Harada

2.  Digital Light Processing (DLP) – What is it? ◦ Method of displaying images in a purely digital realm ◦ Made possible via the use of a Digital Micromirror Device (DMD) ◦ Extremely reliable for a mechanical device  History ◦ Created in 1987 by researchers at Texas Instruments ◦ Current structure of DMD pixel was developed in 1997

3.  Rear Projection ◦ 1-DMD  Front Projection ◦ 1-DMD ◦ 2-DMD ◦ 3-DMD

7.  Mirror structure is built on a standard CMOS 6T SRAM cell  Series of alternating metal and sacrificial layers used to build the structure  Some sacrificial layers are only removed during the packaging process

8.  Pulse Width Modulation ◦ Used to create varying shades of grey when reflecting white light ◦ Same processes used to create shades of red, green, and blue by reflecting light of these respective colours  Human Visual System ◦ Combines the various colour light pulses to form the final perceived colour ◦ Care must be taken in the choice of pulse patterns to avoid visual artefacts

9.  Extremely reliable  Possible problems: ◦ Hinge fatigue  Thin film materials are more compliant and less stiff  Distinctly different properties from macroscopic concept of bending metal (e.g., aluminium foil) ◦ Mirror damage due to operation at high frequency  In 5 us, the mirror tip moves 2 um with an average velocity of 40 cm/s  Terminal velocity of an oak leaf falling from a tree is approximately 100 cm/s

10. ◦ Adhesive forces  Capillary water condensation can cause the landing tip and surface to become stuck due to surface tension  van der Waals forces  Short range forces which cause materials to become attracted at molecular level  Solutions:  Redesign in 1995 added miniature springs to mirror landing tips  DMD sealed in a dry environment using hermetic packaging techniques

11.  Digital Micromirror Device is the heart of the Digital Light Processing system  The only purely digital projection system  Extremely reliable  Potential problems not posing any problems due to manufacturing environment and physics on the microscopic level