DLP / DMD Technology & Texas Instrument Jessica Lau

Background - DMD Digital Mircomirror Device (DMD) Invented by Larry Hornbeck of Texas Instrument Semi-conductor light switch Rectangular array of up to 1.3 million of hinge-mounted movable microscopic mirrors Size of a fifth of human hair Each mirror correspond to one pixel of image Mounted over a CMOS SRAM SRAM – Static Random Access Memory

DMD Not operating – parked at 0 degree On – Tilt +10 degrees Off – Tilt –10 degrees On/Off Switching – 1000 times/sec 848 x 600 DMD Consists of 508,800 tiny, tiltable mirrors A glass window seals and protects the mirrors.

Background - DLP DLP – Digital Light Processing Proprietary Display Technology developed by Texas Instrument Imaging system employ the use of one or two or three DMDs Consisted of a light source, color filter system, cooling system, illumination and projection optics, memory and signal processing support.

DLP Imaging System

How DLP works ? DMD chip DLP I – Gray Scale Image DLP II – Digital Color Creation Applications and Configurations

Step 1 – Signal Conversion Accepts both analog or digital signal All signals must be converted into digital Each pixel mapped directly to its own mirror at 1:1 ratio By electrically addressing the memory cell below each mirror with the digital signal, enables mirrors to tilt towards “On” or away from “Off” light source.

Step 2 – Gray Scale Image “On” – light Pixel vs. “Off” – Dark Pixel Mirror switched on more frequently than off – Reflects Light Gray Pixel Mirror switched off more than on – Reflects Dark Gray Pixel Rapid Switching allows up to 1024 shades of gray reflections Digitalized video signal entering DMD get converted into highly detailed grayscale image

Step 3 – Color Creation Color is added as white light from the lamp passes through a color wheel filter Color Wheel – RED, GREEN & BLUE As wheel spin, mirrors on DMD are tilted on for the exact amount of time required for each basic color Only 1 color is shined onto DMD at a time When spinning fast enough, human eyes blend alternating flashes to view “more” colors in the projected image.

Step 4 – Applications 1-chip DLP Projection System 16.7 millions of colors TV, projector, home theater system 3-chip DLP Projection System 35 trillion of colors 3 DMD configuration Each DMD dedicated to 1 color only White light passes through a prism to divide red, green and blue and later recombine to form image

Advantages Smaller package size Light in weight Higher Contrast Ratio ( by increasing the tilt of mirror to12 degrees, and featuring a black substrate under mirrors) Reduced Pixelation (less visible pixel grid compared to LCD)

Disadvantages “ ” Varies for different people “ ” (Use of spinning color wheel to modulate image causes color to separate out in distinct red, green and blue in any given instant of time) Varies for different people Break out and rapid sequencing of color blamed for headaches and eyestrain 1st generation – 60Hz, 3600RPM, 1x 2nd generation – 120Hz, 7200RPM, 2x Today – 120Hz, 7200RPM, 4x (6 segments of color wheel, double refresh rate) THE RAINBOW EFFECT 60 hz - Update color 60 times per second 1x – rotational speed

Q & A