sumesh(dmd)

8/3/2019 sumesh(dmd)

http://slidepdf.com/reader/full/sumeshdmd 1/17

WELCOME - ALL OF YOU



DIGITAL MICROMIRROR

DEVICE(DMD)

Submitted by

SUMESH. E.MS7ECENO:41



WHAT IS DMD?

DMD IS AN OPTICAL SEMICONDUTOR THAT

IS THE CORE OF DLP PROJECTION

TECHNOLOGY IT IS SIMPLY KNOWN AS MIRROR ON CHIP

SIZE OF ONE FIFTH OF HUMAN HAIR.

IT IS THE COMBINATION OFELECTROMECHANICAL AND OPTICAL

FUNCTIONALITY



DMD

DMD is a member of MEMS and is electro

mechanical switch.

The DMD is fabricated over a CMOS memory

Each light switch has an aluminum mirror, 16

micro m squares, that can reflect light in one of

two directions, depending on the state of the

underlying memory cell.

DMD is based on the pulse width modulation

technique.



DMD cell Architecture

The fabrication of the DMDsuperstructure begins with acompleted CMOS memory ckt

A thick oxide is deposited overmetal-2 of the CMOS and thenplanarized using a chemicalmechanical polish (CMP)technique.

Rotation of the mirror isaccomplished throughelectrostatic attractionproduced by voltagedifferences developed betweenthe mirror and the underlyingmemory cell



THE MIRROR AS A SWITCH



FUNCTIONAL BEHAVIOR OFDMD

i. All are tiltable mirrors

ii. Each pixel corresponds to one colour

iii. When the memory cell is on (1) state, the mirror rotates

to +10 degrees

iv. when the memory cell is in off (0) state, the mirror rotates

to – 10 degrees

v. Grey scales are created by controlling the

proportion of ON and OFF times of the mirror

during one frame period

vi. Motion video display is created by changing the

SRAM data at the video frame rate



BLOCK DIAGRAM



Actual Working of DLP

The analog signals are digitized, decoded to Y/R-Y/B-

Y signals. The Y/C signals are then

converted from interlace to progressive format

The progressive scan-rate Y/R-Y/B-Y signals

are converted to R/G/B data in the Color SpaceConversion block.

This data is subjected to a degamma operation

Translates the R/G/B data into bit plane level datausing PWM technique.

It is used to drive the DMD display.

C ti f C l



Creation of Colour When a white light from the lamp is passed

through a color wheel filter, color is added Color Wheel consist of – RED, GREEN &

BLUE colors which rotates at high speed.

As wheel spin, mirrors on DMD are tiltedON

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.



COMPARISON

DMD DISPLAY

HIGH PIXELEFFICIENCY

HIGH FILL FACTOR

HIGH PICTUREQUALITY

LCD DISPLAY

COMPARITIVELYLESS

LOW FILL FACTOR

COMPARITIVELYLESS



Seamless Picture Advantage

The square mirrors on DMDs are 16 µm ²,separated by 1µmgaps, giving a fill factor of up to 90%.

DLP- PROJECTED

IMAGE

LCD-PROJECTED

IMAGE



APPLICATIONS

COMMONLY USED IN HDTV WIDELY USED IN HOLLOW GRAPHIC

VERSATILE DISC

DMD IS THE HEART OF DLP



ADVANTAGES

HIGH RELIABILITY

HIGH ASPECT RATIO HIGH CONTRAST RATIO

HIGH STABILITY



Disadvantages

“ ”

(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)

Break out and rapid sequencing of color blamed

for headaches and eyestrain



CONCLUSION

The general movement of the display industry

is in the digital direction

DMD-based displays preserve the digital

integrity of the source image all the way to the

eye.

The result is the best possible video quality.



THANK YOU!

sumesh(dmd)

Documents

Transcript of sumesh(dmd)