Visualization Stations – The Big Picture Within Reach
LCD display panels come in all kinds of sizes. From the computer monitor on your desk to the television in your living room, these displays have become the de facto standard for high-resolution display products. In the commercial world, LCD displays are available up to 100” diagonal, and beyond. These large displays can be considered as the foundation to a Visualization Station all by
There are two major issues with tiled LCD video walls.
First, tiled LCD displays have seams. Economy LCD displays have bezels. No matter how you consider it, it’s like looking through a multi-paned window. The new LCD video wall displays have seams less than 2mm. Some have seams less than 1mm. There’s still a visible seam. Second, standard LCD displays offer around 500 NITS brightness. (consumer LCD panels typically have <400 NITS) Several manufacturers offer 700 NITS or greater output on their specialty LCD displays. In a high ambient light environment, even 800 NITS might not be enough brightness resulting in a washed-out look. This is certainly true where direct sunlight is in play. According to SMPTE (Society of Motion Picture and Television Engineers), the ratio of display brightness and light from ambient sources should be a ratio of at least 5:1. As a reference, sunlight streaming through a window will often exceed 20,000 lux! Direct sunlight outdoors can be 125,000 lux! NITS x Pi = lux Lux / Pi = NITS Using this formula, a 350 NITS consumer LCD display outputs 1100 lux. Then, using the 5:1 SMPTE recommendation, you can extrapolate that the consumer LCD can operate properly in up to 220 lux ambient lighting. You can likewise say that a 500 NITS commercial LCD display outputs 1570 lux. When you divide that by 5, the maximum ambient light is 314 lux. The right way to calculate this is with a light meter. It’s a worthwhile tool to have. Say, you measure the ambient light in a corporate lobby on a sunny day at 2,000 lux. Will an LCD video wall be the right choice? Let’s work backward. 2,000 lux divided by Pi (3.1416) equals 637 NITS. Apply the 5:1 rule and multiply 637 x 5 = 3,185 NITS. That’s what you need to reproduce a good picture on a sunny day. No, the LCD video wall would not be a good choice.
High-output video projectors have a place in the large video wall space. They can produce a very high lumen (lux per square meter) output. Especially when considering the new laser-driven projectors, this can provide a huge image at a reasonable cost. The caveat with projection is that ambient light can wash-out the projection screen. So, to determine whether projection is the right choice you must consider again the ambient light conditions.
Let’s work that out.
First, edge-blended projectors should have an overlap of about 30% to get the best results. So, if you need to have a 3840 x 1080 image, you need three, not two projectors. Two projectors will give you about 2688 x 1080, ideally. I’ve done video backdrops with three projectors and about a 35:9 aspect ratio. So, let’s say we’re making a 35’ x 9’ video backdrop like I did. We must deal with each projector by itself. So, each projector can fill a 16’ x 9’ screen. To find the lumens needed, calculate the total area of the screen in square feet. Measure the amount of ambient light at the screen location. Multiply that number by 5 and multiply the result by the area of the screen. In this case, the ambient light at the screen is only 10 foot-candles. 10 x 5 x 144 = 7200 lumens. We’ll need three, 7200-lumen projectors. Now in most cases, you’ll have much more ambient lighting than I had on-stage in a controlled lighting environment of an auditorium. But, you get the idea. You also can see where it can get impossible in high ambient light situations.
Let’s work this out.
We’re specifying a direct-view LED display for a house of worship. The first row of seating is about 20 feet back from the display location. 20 / 3.5 = 5.7mm pitch. There’s no available 5.7mm pitch available, so you’ll choose between say a 4mm, and a 7mm. In this case, I’d recommend using the 4mm because there’s not a huge difference in cost. However, in close viewing, and especially in interactive environments like boardrooms where the presenter might be right up on the display, the cost between a 1.2mm and 0.9mm pitch can be quite a lot of money. In summary, there are a few solutions to consider. Whether you choose LCD, projection, or direct-view LED will depend on all of the criteria we discussed here, as well as the total cost of ownership. When you have a project that requires a large video display solution, call your Starin team and we’ll assist you in choosing the correct solution and we’ll provide a complete, turnkey solution that guarantees success for you and for your customer.