ALEXANDRIA, VA.—Although 4K cameras and their respective monitors were all over the floor of the NAB Show, new technologies are proliferating for 1080p displays and their smaller cousins that are used for camera monitoring and field production.
CRT displays have been the gold standard for many years when the requirement was for precision quality-control monitoring. However, it’s getting hard to find CRT monitors, and improvements to flat-panel displays, combined with technology changes that reduce (although not eliminate) the need for calibrated displays, make flat-panel LCD monitors the most popular choice today.
Traditional LCD displays use a cold-cathode fluorescent lamp (CCFL) as the light source behind the LCD layer. This has worked well over the years, with good reliability and low power consumption. However, several variations on flat-panel display design are starting to push LCD/CCFL aside as the predominant monitor technology.
Still, LCD display technology is getting more refined with each passing year. LCD displays are low-cost, lightweight and can produce excellent images, and new LCD developments such as In-Plane Switching (IPS) promise to give LCD displays much wider viewing angles and better visibility in bright light.
Panasonic BT-LH2170 IPS monitor Panasonic recently introduced the BT-LH2170, a 21.5-inch LCD production monitor with IPS technology. Intended for critical viewing, one of the big benefits of IPS is that it permits a very wide viewing angle.
“The LH2170 will incorporate advanced 3D assist functions and expanded display functionality such as in-monitor display, Y-Map display that makes it easy to confirm luminance level map, a Zebra display that is the same function that a pro camera utilizes to detect the level over or assigned in between level portion, and a two-window display that can be used in combination with the Y-Map or Zebra displays,” said Steven Cooperman, a product manager for Panasonic.
IPS works by putting the liquid crystal structure parallel to the viewing surface, which improves the viewing angle and overall brightness. Instead of a CCFL light source shining through a relatively deep LCD matrix, IPS puts the light source closer to the display’s surface, thus widening the viewing angle. IPS usually offers an improvement in viewing in bright light, as well.
Panasonic’s approach is to not only incorporate IPS, but add useful features to the monitor that make it easier for technical staff to evaluate the image.
LED BACKLIGHTING
Another improvement in LCD technology is the use of LEDs for the backlight instead of CCFLs. It’s important to understand that displays with LED backlights are not technically “LED” displays, but rather LCD displays that use LED backlight. These LED/LCD hybrids bring big benefits with deep blacks and improved contrast, thinner cases, lighter weight and lower power consumption.
With an LED backlit display, each LED can be addressed independently and turned on and off as needed. With the light source off, the pixel becomes a true black, instead of the dark gray that results from a CCFL being constantly on behind the black pixel. The resultant leap in contrast ratio is easy for anyone to see.
Since individual LEDs are turned on and off, LED backlight assemblies usually draw less power than CCFLs of the same size, which means the monitor draws less power and produces less heat.
The hottest new display technology for the past couple of years is the organic light-emitting diode (OLED), and it’s not really all that new—the technology behind OLED was patented in the early 1980s. Although OLED displays have been available by the millions in cell phones for the past three years, developing the technology for larger displays has proved a challenge.
For one thing, some implementations of OLED tend to have relatively short life, in the five-to-seven year range. This is not a problem for cell phones, as even the most high-tech and expensive phones are discarded as hopelessly obsolete after two or three years.
However, life is much different for an expensive professional video monitor, and customers will expect them to work for 10 years or more. That’s the big reason why just a handful of companies (notably Sony, TVLogic and Marshall) have released OLED displays.
“The performance [of IPS displays] was not for critical monitoring applications and we decided to look into other methods,” said Gary Mandle, senior product manager, Sony Electronics. “OLED is definitely one of them.”
PIXEL-SIZED LEDS
The big benefits of OLED stem from the fact that the display actually consists of pixel-sized LEDs. The surface of the display emits the image, which means that OLED monitors have superb viewing angles as well as high brightness because the light from the LEDs does not pass through a controlling matrix such as that used in LCD/LED hybrid displays.
Since every pixel can be switched on and off, the contrast from an OLED monitor is exceptional. Finally, OLED displays are amazingly slim and can be as thin as a sheet of cardboard, with resultant savings in weight.
Sony now has OLED monitors in its product line, including the BVM-E250 25-inch OLED display. The BVM-E250 features multiple color gamut display (SMPTE C, EBU, ITU-R BT709, S gamut and native) and a 12-bit professional display engine, in addition to traditional OLED characteristics that include powerful contrast ratios and exceptionally wide viewing angles.
Other companies are watching the development of OLED but are refining other advances before committing to OLED.
“The issue with OLED so far has been low MTBF and the higher cost,” said Larry Enroth, director of sales for broadcast and post-production at ViewZ in Anaheim, Calif. “We are hoping to see improvements in the marketability over the next year. In the meantime, the biggest advance is back-lit LED displays with 12-bit internal processing, zero dead pixels and 33,000 hours MTBF.”
Last year, one OEM panel manufacturer announced that it had developed a blue pixel layer, the “Achilles heel” for OLED displays, with a typical life of 38,000 hours—equivalent to more than four years of continuous operation. Assuming those numbers hold up, there may be more OLED monitors in the next couple of years.
MORE FEATURES
Some manufacturers may be waiting for the right moment to develop OLED displays, but there are many other ways to design monitors that meet the needs of today’s video producers. For example, the Plura MVM-147-16 is a 46-inch LCD monitor with a built-in 16-input multiviewer. In addition to displaying up to 16 video signals on a single panel, the MVM-147-16 also can display a clock, audio levels and loss-of-video alarms.
At the other end of the size spectrum, Ikegami has the nine-inch HLM-907WR LCD monitor. In a rugged case, the HLM-907WR has a 1280 x 720-pixel display, making it one of the few small monitors that has a true HD image. That makes it a good choice for a producer’s monitor in production trucks and for field monitoring.
There are monitors available for many other specializations, such as 3D and the latest: 4K monitoring.
“4K is taking off, but it’s still in its early stages when talking about professional displays,” said Sony’s Gary Mandle. “There are many things changing as we speak—we are investigating 4K potentially using OLED and also Crystal LED.”
There will continue to be refinement and advancement in professional video monitors, as well as continued creativity shown by manufacturers with monitors that pack in more features and capabilities.
