Session 7: Consumer 3D TV Displays: What are the Technical Differences?
Peter Putman, Contributing Editor, Pro AV
Emissive Displays: CRT Imaging, Plasma, OLED
Pulse-width modulation for plasma displays; Because plasmas are either on or off, the must be pulsed for grey scale. Panasonic 3D plasma screens sizes vary between 42” to 103”.
OLED is proving very hard to manufacture in quantity. Brightness and color uniformity is a problem. Epson and Samsung have shown 40” OLED displays. They are super thin at under ½”.
Disadvantages of emissive displays include; color aging (blue channel goes the fastest), glare from ambient light, and they tend to be heavier.
Transmisive displays; LCD, HTPS
LCD displays, 120hz or faster for fast motion, bright saturated color, very high contrast and rightness, and the front LCD can be polarized for 3D.
LCD HD and 3D TVs are moving to backlit rather than reflective displays. The leading manufacturers are moving to 240hz and 480hz. The IR emitters are embedded in the front borders.
High Temp Poly Silicon (HTPS) projectors are just getting started in the marketplace. Typically they use short arc lamps or LEDs for the light source. LEDs last longer – 30,000 hours.
Disadvantages of transmissive displays include; narrow viewing angles, color shift, black level, contrast, cross-polarization can cause 3D images to black out. LCDs do poorly under high ambient light (washout), and motion blur issues (requires partial black frame insertion / LED backlights can help).
Reflective displays; DLP, LCoS, D-ILA
They can give you bright, saturated colors. LCoS can handle 120 hz, and DLP can produce extremely high switching rates. DLP for 3D home projectors is quite possible. There are two versions of DLP; RGB and RGB+white. The white can be used for flashes that synchronize the active shutter glasses.
Disadvantages of reflective displays include narrow viewing angles, color breakup artifacts, and lower contrast and black levels in D-ILA.
Finally, he reviewed the HDMI mandatory 3D formats. The info is available on the HDMI website.
Conclusion: the best 3D TVs so far are
– Plasma TVs,
– OLEDS,
– 3 chip DLP projection, and
– LED-backlit LCD TVs.