In the past decade touch screen technology has been integrated into almost every facet of our lives, from smart phones and computer tablets to public information kiosks. While innovative technologies developed over the past few decades have been tried and tested, many touch screen options don’t work well in the more demanding environments of in-theater military applications or industrial workspaces. Some of the most commonly used forms of touch screen technology today include capacitive touch, surface acoustic waves, Infrared (IR) Touch, and resistive touch. There are many other forms, such as optical touch, multi-touch analog resistive (MARS or AMR), dispersive signal, and acoustic pulse recognition, but these are not as widely used. Below is run down of the more popular types of touch screen technology, their benefits and drawbacks, and whether those technologies work or don’t work for rugged use.
Most everyone is familiar with projected capacitive (p-cap) touch as it is used commonly in smart phones and tablets. This technology has many advantages including the ability to provide excellent image clarity and brightness, withstand heavy use and abuse, and offer multi-touch input. But for many military and industrial applications, it is has drawbacks. The p-cap touch screen must be touched by a finger or conductive stylus. In environments where gloves are likely to be worn and styluses are likely to be lost, the potential work disruption is undesirable. Also, the electric field projected from the touch screen creates an EMI field that can interfere with other equipment or be detectable by hostile forces. These two factors remove projective capacity touch screen technology as a viable option for most military and industrial applications.
Surface Acoustic Wave (SAW)
This newer technology is competitive because it offers durability and excellent optics. Like projective capacitive, it has excellent clarity, light transmission, and resolution. It can also sense pressure as long as you are using a soft-tipped object, which means that gloves can be worn during use. But for rugged applications, it has one major drawback in that it operates by registering sound waves. The device will register false touches due to the vibration that occurs in many industrial and military applications. This makes SAW a technology inappropriate for most rugged environments.
Analog Resistive Touch
Analog Resistive touch is a proven technology with many benefits, including low electromagnetic interference (EMI), low cost and lower power consumption. The touch resolution is very high (typical 4096 x 4096), allowing it to work well with programs requiring written input. Since it is pressure sensitive, the user can input data while wearing gloves or using a stylus, and it reduces the chance of accidental input, e.g., it won’t register a fly landing on the screen. As with all technology options, there are some minor drawbacks. Only single touches are registered; multi-touch is not a viable option. Also over time, the touch placement will drift, especially in extreme temperature or high humidity environments. Periodic calibration of the screen is required, but is a simple and fast procedure. The resistive membrane also reduces the light emission of the display by about 10%.
Infrared (IR) Touch
IR Touch is also a proven technology. It has excellent optical properties since there is no overlay over the screen. It supports large screen formats, is extremely durable, and will respond to any input device that will interrupt the light signal crossing over the video screen. This technology will also support multi-touch, allowing upwards of 10 simultaneous points of input. There is no EMI generated, and with NVIS Filters it works well for night-vision applications, both important for many military operations. IR touch can be installed over display surface enhancements such as bonded glass Anti-Reflective (AR) filters. The only drawbacks would include accidental input and minor pointer drift. The screen doesn’t have to actually be touched for input, only the light grid floating directly above the glass needs to be interrupted, e.g., a fly landing on the screen would register. Also, at very large sizes the cursor can drift near the corners. But the drawbacks are minor relative to the benefits.
What We Choose for Chassis Plans’ Rugged LCD Products
Chassis Plans has recently introduced IR Touch with multi-touch technology for its 24” rackmount LCD monitors, the CPX1-24 and CPI1-24. This is one of the only multi-touch screen rugged monitors this size in the market. It’s appropriate for military and industrial operations, offers expansive workspace, is extremely high resolution at 4096×4096 points, requires no touch activation force, is sealed to IP65 from the front, and supports multi-touch gesture technology. Chassis Plans offers analog resistive touch options for most of its rugged LCD products because of its many benefits, including durability and reliability. Our RhinoTouch® surface technology protects the monitor surface layer from humidity, scratches, vandalism, flames, chemicals, and more. RhinoTouch® also provides an option for a finger print resistive oleophobic Anti-Reflective coating.