Thanks to these features and additional refinements to the SXRD panel structure, contrast is substantially improved over H-LCD designs. The contrast ratio of Sony's 4K SXRD panel alone is better than 4000:1, when measured with a conoscope, a tool for analyzing the optical properties of bifringent materials. Total contrast ratio of Sony 4K projectors, when viewed on a screen with unity gain is greater than 1800:1. That's comparable to other digital projection technologies.
Long operating life
CRTs have phosphors that are subject to burn-in when an image stays on the screen too long. Projection CRTs are particularly susceptible, because they run at higher output to achieve high brightness. Fixed-pixel projector display panels are immune to burn-in, offering far longer life. And the SXRD panel is particularly robust.
Two thin sheets of material hold the liquid crystal in alignment. Typically this material is organic polyimide film. This generally works well but has less than optimal operating life in the stressful, high-heat environment of a digital projector. Sony's inorganic thin-film alignment layer not only maintains vertical liquid crystal alignment but also exhibits exceptional thermal stability. This extends the operating life of the SXRD panel.
In addition, H-LCD panels are squarely in the light transmission path, making them relatively difficult to cool. Because light reflects off the SXRD panels, their "dark" side is out of the light transmission path, making them easier to cool. This prolongs the panel life further still.
Minimum artifacts
There's more to picture quality than just the microdisplay panels. Electronic and electro-mechanical systems associated with the microdisplays can add artifacts not present in the original picture. These artifacts may be visible depending on picture content and viewing circumstances. When comparing microdisplay projection systems, three potential sources of artifacts stand out.
•Color wheels are used in consumer and affordable business-class projectors to generate multiple colors from a single microdisplay panel.
•Optical actuators are used to double the native resolution of the microdisplay panel.
•Spatial dithering is used to conceal limitations in a microdisplay panel.