Electronic Design

Digital Video Peaks As CRTs Continue Downslide

Most people couldn’t care less about high-definition television (HDTV) and other advances in digital video technologies. In fact, one in four people think they have HDTV when they really only have one or two of the four components necessary for true HDTV: HD signal, HD TV set, HD receiver, and HD antenna or dish (unless, of course, you have cable).

For other people, though, HDTV is long overdue. I’ve owned an HDTV for several years now, but I didn’t bother with the other components until last month. That’s because until recently, there was no compelling reason for me to take the plunge. I just finally got tired of going to other people’s houses to watch sports in high definition.

And I’m not alone. According to the Sports Video Group of the Consumer Electronics Association, 22% of sports fans watch sporting events in HD they otherwise wouldn’t have watched. Even more amazing is that 22% of non-sports fans start watching more sports after getting HDTV.

So maybe there’s something fascinating about being able to make out the details of a divot or see the drops of sweat on an athlete’s face that brings the realism of the game into your home. Suddenly, the folks who thought they didn’t want or need HDTV now must have it. Expect lots of folks to join me in making the move to HD this year for several reasons:

  • Just about everything revolving around HD is improving, from picture quality to significant price breaks.
  • All broadcasts must be in HD by February 2009.
  • According to DisplaySearch, based on the expected number of HD-capable TV shipments this year plus those sold in prior years, the number of potential U.S. HDTV users will be 76 million.
  • National broadcast networks like ABC and Fox continue to provide more and more HD broadcasts while companies like HDNet provide round-the-clock HD broadcasts.

For a breakdown of digital television technologies, including the difference between progressive scan (the p in 1080p) and interlaced (the i in 1080i) applications, as well as how the technologies work, see “Tuning In To Digital TV.”

“Mr. Green, He’s So Serene, He’s Got A TV In Every Room”
Perhaps you’ve seen the commercial where a man is watching a soccer game while going through his daily activities, and no matter which room he walks into and no matter his viewing angle, he can keep watching the game. This commercial is quickly becoming a reality as television enters some interesting new venues.

For example, TV is making its way into portable media players, mobile phones, and even handheld video games (see “High-Resolution Television Coming To A Cell Phone Near You). The implications of this video explosion are tremendous.

Soon, you’ll be able to catch that episode of CSI under virtually any circumstance and be able to continue watching even if your circumstances change. If you’re watching a show on your couch in your living room, you can continue to watch it in your car and wherever your final destination may be, as long as you have a broadcast signal.

LCDs Steal Market Share From Plasma Displays
Liquid crystal displays (LCDs) have overcome low contrast, poor color accuracy and angle of view, and motion blur to become serious candidates in the HDTV market.

Traditionally, poor contrast ratios lead to dark images and washed-out black backgrounds. Technologies such as Samsung’s patterned vertical alignment (PVA) helps to shut out light from bright backlights in dark scenes, allowing for a static contrast ratio up to 2300:1. This technology also helps increase the view angle.

Motion blur is a problem with LCDs due to their nature as a “hold-type” display, where images are maintained throughout the entire frame, which causes moving images to blur. This is in contrast to CRT-type displays, in which images only persist for a short time after being written to the screen.

To combat motion blur, a refresh rate of 100 or 120 Hz (up from 50 or 60 Hz) is used. But just increasing the refresh rate won’t eliminate motion blur. That’s why Samsung developed Motion compensated Frame Interpolation (McFI), which estimates (interpolates) motion between frames based on actual information contained in each adjacent frame.

Plasma displays suffer from disadvantages like the need to create light before modulation, higher power consumption, and image burn-in. They also become increasingly difficult to manufacture when trying to maintain high resolution as the screen size is reduced. This is why you never see plasma used in small applications, such as cell phones.

As the price of LCDs continues to fall with respect to plasma displays, they will continue to grab market share. Of course, some sort of breakthrough in plasma technology could change the dynamics and reverse the trend.

And if 2006’s “Black Friday” (the day after Thanksgiving) is any indication, HD LCD televisions are set to have a very good year. According to the NPD Group, a market research company, only 75 40-in. or larger LCD TVs capable of 1080p were sold in the U.S. on 2005’s Black Friday. Last year, that number soared to about 22,000 units.

(Based on the NPD Group week ending Nov. 25, 2006, the weekly point of sale information is derived from a subset panel of retailers that also contribute to NPD’s projected monthly point of sale panel.)

LCDs of other sizes and resolutions experienced this growth as well. The NPD group also noted that CRT TVs often were still available later that weekend while LCD and plasma TVs sold out on 2006’s Black Friday (see “LCD TVs Get Ready To Take Over The Market”).

HD DVD vs. Blu-ray
Remember the Betamax versus VHS bout of the 1970s and 1980s? Get ready for the next big battle: Blu-ray versus HD DVD (Fig. 1). As these heavyweights go head to head this year, the hype will be hot and heavy, and there’s the potential for some drawn-out lawsuits.

Consumers will be the beneficiaries as well as the victims of such a war. Benefits will include a rapid price drop in both equipment and HD media. But the drawback will be the same as it was with Betamax versus VHS—not all movies will be available in both formats until a clear winner emerges.

Blu-ray can hold up to 50 Gbytes per disc, while HD DVD can hold up to 30 Gbytes. Currently, Blu-ray technology also costs more (see “HD DVD Versus Blu-ray” at Drill Deeper 14521 and “Standards Around The House”).

A New Beginning
As soon as you make up your mind and plop down a few hundred dollars for a Blu-ray or HD DVD player, you may wake up the next day and find that your purchase has become obsolete. Say hello to Displaytech’s holographic data storage (HDS).

This technology uses spatial light modulators (SLMs) based on ferroelectric liquid crystal on silicon (FLCOS) technology for a storage capacity that’s 10 to 100 times larger than HD DVD. InPhase Technologies currently is incorporating SLM into HDS drives.

Essentially, holograms are created by splitting two beams of light with a laser. The split causes the beams to interfere with one another, forming a pattern that includes phase and amplitude information for each beam. Next, a photorefractive material is placed at the point where the laser interferes with the beams.

This allows the interference pattern to be recorded on the material. Information then can be reconstructed by removing one of the beams of light, in which case the hologram causes light to be diffracted in the direction of the beam that was removed. At that point, the original information may be reconstructed.

According to IDC, commercially available HDS drives will appear sometime this year, with the technology competing for market share by 2010. But don’t worry. You can justify getting an HD DVD or Blu-ray player now by purchasing the latest gaming console from Sony, Nintendo, or Microsoft, which include blue laser disc players (Fig. 2).

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