Blu-ray Disc Demystified in Software

Paint QR-Code in Software Blu-ray Disc Demystified

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In recent years, there has been a dramatic expansion in the area of new display technologies We have gone from a world dominated by cathode ray tubes (CRTs) to one in which it will soon be difficult to find one With advances in these new display technologies, it is important to understand how Blu-ray and DVD are affected If you go down to your local consumer electronics store, you will see that standard definition televisions have all but disappeared, and there is a wide array of widescreen high definition displays available Most standard televisions are of the CRT genre and although there are a small number of CRT widescreen televisions still available, most widescreen displays are either plasma or LCD The leading reason for this differentiation is size It is very difficult to manufacture a glass tube CRT at very large sizes Given that the CRT is a type of vacuum tube technology, the tube itself must be able to structurally withstand the pressure of containing a vacuum without imploding As the tube grows larger, this becomes more difficult without any sort of internal support Additionally, it s a lot of glass, making it expensive and, more importantly, HEAVY Does that mean CRT is going away Almost, but not completely It s true that a 500+ pound CRT television will have a difficult time competing against the convenience of a relatively light, wall-mounted plasma screen or LCD Even in situations where taking up a large

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space is not a problem, the convenience of a lightweight DLP system may outweigh (pun intended) the CRT heavyweight However, it will be a shame to lose CRTs For one thing, there has been over 60 years of research applied to developing the color display technologies that CRT uses, including phosphors, screen masks and color dot distribution to name a few However, as the new technologies mature, considerable improvements have been made that are proving to make the good ol CRTs relics of a bygone era

Digital light processing (DLP) This type of display is based on the digital micromirror device (DMD), a silicon chip whose surface is covered by a matrix of tiny mirrors Through electrical signals, these mirrors can toggle from an off position to an on position and back Basically, each micromirror represents a pixel; by reflecting a light source off the mirror, one can project a black and white image Flickering the mirror at variable high rates creates the impression of varying amounts of light, thereby displaying a grayscale Passing the image through a rotating color wheel that is properly synchronized with the mirror flashes generates a color display This is the basis for most consumer rear-projection DLP televisions, which can offer a bright, crisp picture However, depending on the color wheels used and the sophistication of the display logic, DLP displays tend to have difficulty reproducing some of the darker color ranges Likewise, being a rear-projection device, there may be some light bleed, which can wash out the image, making black areas appear gray Some DLP displays may exhibit color shift problems, exaggerated sharpness, and excessive brightness The latter two characteristics, in particular, can overemphasize encoding artifacts in video Plasma display device panel (PDP) Plasma displays work by applying a charge to a small gas-filled cell The gas becomes ionized and, in turn, interacts with a phosphor on the surface of the cell, which glows a given color Because plasma displays work with phosphors, they are able to utilize much of the research that has gone into phosphor research for CRTs and reproduce more natural colors However, it also means that they may burn in quickly, just like a CRT, leaving a permanent after-image where something remained on screen for a length of time For example, channel logos that occupy a corner of the screen can begin to burn in after a period of time Plasma displays can consume large amounts of power compared to other types of displays, and tend to suffer from bleed-over effects in which the plasma from one cell bleeds over to other cells Liquid-crystal display (LCD) Liquid-crystal displays operate by sandwiching color filters and polarizing filters on either side of a liquid-crystal cell matrix, and placing a white backlight behind the sandwich The backlight remains lit while the display is active The liquid crystal in each cell, by default, stays curled up such that it blocks the polarized illumination from the backlight When a charge is applied to a cell, the crystal unwinds, allowing the illumination from the backlight to escape through the color filter One of the most noticeable problems with LCD is the limited viewing angle, although with the latest updates to these technologies, the viewing angle has been extended dramatically (up to as much as 178 degrees) Increased viewing angle tends to lead to increases in light bleed white light that escapes to wash out the picture and raise black levels In addition, the unwinding process