IPS, LED, OLED: The Latest Advances in Flat Panel Video Monitors
New technologies are on the horizon for production displays, as well as camera and field production monitors.
CRT displays have been the gold standard for precision quality-control monitoring for many years, but it’s getting hard to find CRT monitors these days. Improvements to flat panel displays combined with technology changes that reduce (but do 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 technology has worked well over the years, with good reliability and low power consumption. However, several variations of 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 recently introduced the BT-LH2170, a 21.5” LCD production monitor with IPS technology intended for critical viewing. One of the primary benefits of IPS technology 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, and a two-window display that can be used in combination with the y-map or zebra displays,” says Steven Cooperman, a product manager for Panasonic.
In an IPS display, the liquid crystal structure runs parallel to the viewing surface. 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 overall brightness as well.
Panasonic’s approach is to not only incorporate IPS but also add useful features to the monitor that make it easier for technical staff to evaluate the image.
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; rather, they are LCD displays that use an LED backlight. These LED/LCD hybrids bring big benefits: 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.
A recent trend in display technology is the use of organic light-emitting diodes (OLEDs), though 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 lives—in the range of five to seven years. This is not a problem for cell phones, as even the most high-tech and expensive phones are discarded as hopelessly obsolete after just two or three years, but life expectancy is much different for an expensive professional video monitor. 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 brought OLED displays to market.
“The performance [of IPS displays] was not for critical monitoring applications and we decided to look into other methods,” says Gary Mandle, senior product manager, Sony Electronics. “OLED is definitely one of them.”
The benefits of OLED displays—including high brightness and wide viewing angles—stem from the fact that the display actually consists of pixel-sized LEDs; 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, some 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” OLED display. The BVM-E250 features multiple color gamut display (SMPTE-C, EBU, ITU-R BT.709, 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 established technologies before committing to OLED.
“The issue with OLED so far has been low MTBF and the higher cost,” says Larry Enroth, director of sales for broadcast and postproduction at ViewZ. “We are hoping to see improvements in the marketability over the next year. In the meantime, the biggest advance is backlit 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” of 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.
Some manufacturers may be waiting for the right time to develop OLED displays, but there are many other display technologies that will meet the needs of today’s video producers. For example, the Plura MVM-147-16 is a 46” 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 can display a clock, audio levels and loss-of-video alarms.
At the other end of the size spectrum, Ikegami has the 9” 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.
Monitors are 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,” says 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.