If a classroom is using a projector to deliver a 100-inch image, which is typically recommended for analytical viewing up to 16 feet away, how easy will it be for an educator or student to interact with content where interaction is a priority? Such a large image isn’t a practical solution and may even be the reason interactive projector sales have fallen dramatically in the last few years.
According to Futuresource, less than 2 percent of interactive whiteboards used with projectors were over 90 inches prior to 2020, while about 75 percent of interactive flat panels purchased in 2022 were in the 75” class or greater. We can extrapolate, then, that most screens used in interactive teaching are between 65 and 90 inches, regardless of whether they use a projector or IFP. Size, for many reasons, should be a secondary priority. The first priority should be useability. Useability includes not only features such as brightness, contrast, and resolution, but also interactivity.
“Brightness” is a buzz word in the world of displays and specifically for projectors. All projectors are bright, but how do they stack up against smart boards and how can they be compared when projectors are measured in lumens and LCD panels are measured in nits? Using an estimated brightness calculator from Projector Central, one can estimate the brightness of a 5,000-lumen projector on a 100-inch screen. According to Futuresource, over 80 percent of classroom projectors sold in North America were less than 5,000 lumens, while nearly every model of a classroom interactive smart board had 350 nits or higher. What we found is that both 5,000-lumen ultra-short throw projectors and interactive displays in 98 inches and 86 inches deliver similar brightness.
So if brightness and size tend to provide an equivalent experience, let’s take a look at another factor: contrast. Contrast is the key to readability of text and graphics, and the indicator where the similarities between projectors and interactive flat panels begin to diverge. Compared to interactive whiteboards, projectors struggle in the contrast department. That’s because classrooms are well lit, whether artificially or naturally. Studies abound that well-lit spaces encourage alertness and productivity and are one of the first hallmarks of the modern-era classroom.
All those bright lights might keep students awake, but they lower the contrast on a projected image, making it harder to read. While projectors need a low ambient light or an expensive projection screen engineered specifically for high contrast, interactive whiteboards hold up in bright environments thanks to their backlit LCD screen. No changes to the room or other investment are necessary. In fact, contrast was one of several motivating factors for Gladewater ISD in Gladewater, Texas, to make the switch to interactive whiteboards for all its classrooms.
In addition to contrast, low resolution also impacts readability. Resolution is the measurement of pixels–little dots of color arranged vertically and horizontally on the screen–that are available to create the image it needs to depict. A 4K resolution, for instance, has 3840 pixels vertically and 2160 pixels horizontally, or 3860×2160 pixels, which totals to over 8 million pixels.
In 2022, about 80 percent of projectors sold to schools in the United States had fewer than 1 million pixels. A typical WXGA resolution–1280×800 pixels–projector on a 100-inch screen delivers less than 15 pixels per inch. If that same WXGA projector is used on a smaller 75-inch interactive whiteboard, that’s still less than 20 pixels per inch. A 75-inch 4K interactive display is able to produce 58 pixels per inch. The result is a detailed image that’s easier to read.
We can’t talk about the comparison between projectors and interactive displays without of course talking about interactivity. Active classrooms incorporate movement into the classrooms. While there are several ways to do this, the most prolific today is at the display. Students are incredibly motivated and excited to use screen technology to learn. The best classroom displays enable a teacher or a student to use their finger, a stylus, or even a paintbrush to write on the screen. Some models have up to 40 points of touch so that groups of students can easily write on the screen simultaneously.
While interactivity is available for projectors, finger touch capability typically comes at an extra cost, and the most popular models only enable six points of touch–a significant limitation for a modern classroom. Also, compared to the best zero bond touch displays, the response time on a projector interactive display is much lower. There’s also calibration involved for a projector, which isn’t always exact and can become glitchy over time.
With more and more classroom environments becoming one of activity and movement, it’s highly likely teachers are moving around too or don’t want to be tethered to their desk and computer. This can mean they’ll need to be supported with tools such as wireless screen sharing for those using devices, or to use an interactive whiteboard that integrates a computer system. An integrated interactive whiteboard is built in to enable PC-free and device-free teaching. These displays are their own devices, featuring software, local storage, and the ability to connect to cloud storage services such as Google. Most interactive projectors are passive devices, requiring the connection and use of a separate computer.
For schools that have determined that interactivity is important, the interactive whiteboard tools available to them will be a vital part of that experience. Whiteboarding software with remote collaboration will allow students to contribute from anywhere. Perhaps the school is simply upgrading their interactive displays; in that case, look for displays that enable a teacher to import their old whiteboard files, including those stored in the industry standard IWB file format. This enables teachers to save and share their best lessons with other teachers without worrying about which whiteboard software they are using. This capability is not offered in a standalone projector.
Cloud storage has become the standard, especially those utilizing Google. The top-selling boards enable teachers to instantly connect to their network and cloud-based drives to access lessons and media content with a single tap. This capability is also now available in the latest smart projectors running either Windows or Android operating systems.
For schools that want to record classroom lessons and lectures and make them available for students to review later, an interactive display with onboard microphones and lecture capture software will enable a seamless experience. Educators can instantly record their voice, record the screen, and mix in audio from other sources like YouTube into a single file that can be shared with students afterwards. This isn’t something a projector will offer.
While the inherent size of a display shouldn’t be the crowning priority, it does bear significance on interactivity. A 100-inch projector screen with a 16:10 aspect ratio is over 4.5 feet tall and can be as tall as 5 feet high. This can make the upper parts of a projector hard to reach for some children. Many schools have constructed stages in front of those projectors being used interactively, which poses a safety risk and makes the screen off limits to those with physical disabilities.
By contrast, an interactive display uses a widescreen 16:9 aspect ratio, which puts the extra
working area to each side rather than on top. This makes it easier for all users to access and for multiple students to work side by side. To create a more inclusive classroom, interactive displays also have the advantage of being mounted on height adjustable stands that can move up and down to accommodate anyone without having to recalibrate the display.
Portable display mounts also introduce another advantage for the flipped classroom model. While it’s nearly impossible to reposition a ceiling-mounted projector in a different area of the room where the activity is happening, with a modern interactive whiteboard mounted on a portable stand, schools can move the display wherever and whenever it’s needed. The cost of these stands is quite affordable, with high-quality models selling for under $500 individually or, when purchased in bulk, for even less.
Safety and Maintenance
The final considerations to make are those of safety and maintenance. Blue light, flicker, and glare are all unique challenges to the interactive display category. Like virtually all mobile devices and LCD monitors, there is risk of increased blue light exposure. Schools that are proceeding with interactive whiteboards will want to select ones certified using EyeSafe® low blue light filters to protect users from this exposure. Flicker-free technology and anti-glare glass will also help to alleviate any eye strain associated with these displays.
For those selecting projectors, zero maintenance will be key. Today, interactive displays, as well as the best laser projectors, are completely dust proof, thanks to a sealed engine design. LCD projector technology requires filters and regular cleaning. If the filters are not cleaned regularly, a projector can overheat, burn out the bulb, and void the warranty of the unit. The labor costs and time costs involved in projector filter cleaning is recognized by COSN as an identifiable recurring total cost of ownership (TCO) using the Gartner TCO model.
The End of the Display Wars?
Interactive flat panel displays have several advantages over projectors, including better classroom ergonomics, advanced usability and safety features, and higher resolution. Projectors create slightly larger images compared to the largest 98-inch interactive displays. But both displays can create bright images, and the cost of a projector and interactive display is about the same when all the extra costs for mounts, screens, and filter maintenance on LCD models are factored in. The easiest way to compare these different types of displays is to evaluate them based on how your teachers plan on using them. For traditional display use and teaching where the teacher is at the front of classroom, both projectors and interactive displays are very effective. If the desire is to flip the classroom, or have teachers move from one location to another, then interactive displays are a more likely choice. Evaluate the use and then the decision will present itself.
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