In the world of Digital Signage, the debate over Plasma or LCD (Liquid Crystal Display) continues to rage among prospective and current customers. But to more knowledgeable professionals in the industry, there are clear lines on when and how to use each of these technologies.
A Burning Question
Plasma technology is plagued with a bad reputation that, frankly, is exaggerated. Yes, it is correct that plasma screens have traditionally been susceptible to what is now infamously referred to as “burn-in”. Burn in is essentially the possibility that images can become permanently visible on the screen after long periods of display This typically happens when static images are continuously shown over a long period of time. It also can occur when items such as a “news ticker” are extensively displayed at in a portion of the screen as is common with many digital signage applications.
The good news is that burn in can be limited and nearly eliminated if the panel is used judiciously. Some simple fine tuning can go a long way to prolong the life of any plasma screen. By lowering contrast levels and brightness, rotating static images and ensuring playlists have plenty of full motion graphics; the potential for burn can be greatly reduced.
LCD panels have a distinct advantage when it comes to burn. It simply does not exist with LCD technology.
Performance
Plasma displays outperform LCD’s in many areas which can be of high importance in digital signage. Most notable of these is what the industry refers to as “Contrast Ratio”. Contrast Ratio is the difference between the blackest black and the whitest white which can be produced on a screen. The greater the difference between the two, the clearer the images will be. LCD’s have traditionally fallen short in this area. To put things in perspective, I will recount a typical equipment specification for any Captive Indoor Media customer.
We like LG equipment and use it in most every customer installation. For Plasma screens, we commonly use a Commercial Grade HDTV with a 10,000:1 Contrast ratio and Brightness levels of 1500cd/m². For LCD’s, we also suggest HDTV enabled panels yet the contrast ratio is only 400:1 with maximum brightness of 450cd/m². To boil things down, contrast ratio and brightness effect viewing angle, clarity of images and ultimately the effectiveness of the media being displayed. And, as is clear from the manufacturer listed specifications, Plasma continues to out pace LCD in image clarity and brightness.
With the above said, I would be remiss if I did not mention that LCD technology is rapidly catching up to Plasma. In fact, 2005 was the first year that LCD shipments exceeded Plasma display sales.
Life Expectancy
As it stands today, Plasma and LCD displays can be expected to last approximately 50,000 hours. This was not the case just a few years ago when Plasma was expected to last closer to 30,000 hours.
In a branch scenario, where business hours typically do not extend beyond 45 hours, a 50,000 hour life expectancy equates to over 20 years. Reality would suggest that 20 years is a high expectation but more important is that both LCD and Plasma are mature technologies. Both can be expected to perform for many years.
The Price
Until recently, there were clear price advantages for both LCD and Plasma as it related to the size of the screen. LCD screens have traditionally been the dominant technology in the smaller sizes while Plasma has been most successful in the 37”+ market. For the most part, this remains true today although LCD’s are competing heavily for a share of the larger screen marketplace.
The Decision
When everything gets boiled down, we typically turn to the size of the area available for the screen, the size of the location and the budget of the customer to help us create the best equipment solution. Frankly we use both technologies with regularity although Plasma remains the most popular, mainly for the performance in the larger screen models.
Today, financial institutions are building bigger branches with more space for customers to gather. Common sense dictates that the larger the screen is, the more visible it will be to the audience and the better the impact it will have.
