Bob Lambermont - Petrobras CRT technology 7 inch 8 inch 9 inch 12 inch Different tube size
Bob Lambermont - Petrobras Scheimpflug correction Projection can’t be done on tilted surface -> focus problem! -> focus problem!
Bob Lambermont - Petrobras Scheimpflug correction Required for projection on tilted screens
Bob Lambermont - Petrobras A picture can be built up with the following three scanning methods : Raster scan (standard CRT projector) Vector scan (e.g. radar screen) Raster-calligraphic (combination of two) Geometry can easily be modified in raster scan through influencing of deflection fields Picture build-up
Bob Lambermont - Petrobras Raster Calligraphic Raster image 1280* HzDay mode 1280* Hz 16 ms Pixel remains onscreen for 10 nsPoint remains onscreen for 1.5 µs 150 times longer !
Bob Lambermont - Petrobras CRT technology Strengths: Resolution (up to 2500x2000) Good contrast Easy geometrical correction / flexibility Color matching and uniformity Digital soft-edge Unbeatable video and data image quality Life time picture tubes Proven technology Weaknesses: Limited brightness up to 500 ANSI Lumen Needs low ambient lighting conditions Setup time Maintenance Not portable
Bob Lambermont - Petrobras Polarization Typical polarizer “eats” 50% of the unpolarized light power
Bob Lambermont - Petrobras LCD pixel By applying voltage over LCD pixel, transmission of light can be modulated.
Bob Lambermont - Petrobras LCD panel: implementation Response speed limited by thickness and characteristics of LC materialResponse speed limited by thickness and characteristics of LC material transmission limited by interconnects and transistorstransmission limited by interconnects and transistors Increase in resolution necessitates higher miniaturization (can be compensated by microlenses)Increase in resolution necessitates higher miniaturization (can be compensated by microlenses)
Bob Lambermont - Petrobras Panel technologies Amorphous Si HT Poly Si normal glass, low cost normal glass, low cost larger transistors => suitable for displays > 3” larger transistors => suitable for displays > 3” external drivers external drivers Quartz glass, expensive Quartz glass, expensive smaller transistors => suitable for displays suitable for displays < 2” integrated drivers integrated drivers
Bob Lambermont - Petrobras LCD Panels Panel sizes inch (p-Si) 3 inch (a-Si) 6 inch (a-Si) 10 inch (single panel)
Bob Lambermont - Petrobras LCD pros and cons +Well-established technology, stable +Compact, rugged, portable +“zero delay” +UXGA resolution available +Efficient in passive stereo projection (see further) -Response speed limited by LC material some smearing in fast moving images -non-perfect black (contrast ratio :1, but improving) -pixellization
Bob Lambermont - Petrobras LCOS: Liquid Crystal on Silicon Essentially: LCD in front of a reflectorEssentially: LCD in front of a reflector Available for microdisplays, projectionAvailable for microdisplays, projection D-ILA is JVC’s trade name for LCOSD-ILA is JVC’s trade name for LCOS
Bob Lambermont - Petrobras LCOS implementation LCD on top of CMOS chip that includes transistors and has reflective surfaceLCD on top of CMOS chip that includes transistors and has reflective surface Aperture ratio is higher than that of LCD (so less pixel visibility)Aperture ratio is higher than that of LCD (so less pixel visibility) Efficiency comparable to LCD due to non- perfect reflectionEfficiency comparable to LCD due to non- perfect reflection Easy to cool the chip!Easy to cool the chip!
Bob Lambermont - Petrobras LCOS addressing Requires complex optics: side at which chip is illuminated is the same as where the light needs to be extracted from!Requires complex optics: side at which chip is illuminated is the same as where the light needs to be extracted from!
Bob Lambermont - Petrobras LCOS integration Complex structure required!
Bob Lambermont - Petrobras LCOS pros and cons +Higher resolutions possible (up to QXGA) +small chip size (1.3” and smaller) +good response speed +good pixellization (smooth image) +higher contrast possible: up to and over 1000:1 reported +chips can be cooled to take high power illumination -alignment hard due to small chip size & high res -difficult to integrate -uniformity? (although seems to be countered now)
Bob Lambermont - Petrobras DMD: another reflective tech Ant leg on DMD chip Does not require polarized light!
Bob Lambermont - Petrobras DMD microstructure Only allows on/off modulation!
Bob Lambermont - Petrobras DMD: grayscale synthesis Frame delay! 1 frame for de-interlacing1 frame for de-interlacing 1 for sending data through CMOS chip1 for sending data through CMOS chip 0-1 frame (depending on gray scale) for gray synthesis0-1 frame (depending on gray scale) for gray synthesis
Bob Lambermont - Petrobras 3-chip DMD integration Each chip runs at 10 bits depth, 60 Hz NOTE: 10 bit Linear Gamma equals 8 bit LCD Gamma 8 bit LCD Gamma
Bob Lambermont - Petrobras 3-chip DMD pros & cons +Excellent picture quality (pixels almost invisible) +can take high power illumination +long life (?) +no smearing (but +good intensity uniformity, good color matching +good contrast (400:1) -Expen$ive! -BIG! -PWM artifacts -TI monopoly -Frame delay -Resolution limited to SXGA -Bright edge around chip makes optical blending difficult
Bob Lambermont - Petrobras Single-chip DMD Sequential illumination of single DMD chipSequential illumination of single DMD chip 3 or 4 segment color wheel3 or 4 segment color wheel chip runs at 8 bit, 240 Hz less bit depth!chip runs at 8 bit, 240 Hz less bit depth! +Compact -Moving part inside, requires synchronization -Motion artifacts (color breakup) due to color wheel
Bob Lambermont - Petrobras Thank you for your attention...