What is the optimal screen size for a mobile device used by a warfighter?  Is it the 7″ to 12″ display of the tablet?  The 3″ to 5″ of the smartphone?  Something in-between?

With the exception of security issues, the folks at the Pentagon and other real-echelon postings do not work in situations that much different than their civilian counterparts.   For its stateside personnel, the Army can probably fulfill its ambitious smartphone program with whatever Commercial Off the Shelf (COTS) products it chooses.

However, warfighters operate in much more demanding environment. Small differences can have huge consequences.

A number of factors favor smaller displays:

1) Rugged-Check the warranty of your laptop carefully, and you’ll probably find that it doesn’t cover displays. Displays are often the most fragile part of a mobile computer, and their vulnerability increases with size.

2) Power– Soldiers carry up to 35 pounds of batteries (Army, Marines Face Uphill Battle To Lighten Troops’ Battery Load).  A smaller display uses less power, and requires fewer replacement batteries.

3) Numerical pad-Some smartphones have increased the amount of real estate available for a display by getting rid of the numerical keypad. However, soldiers like keypads. They often have to digitally enter a great deal of numerical data, and don’t like holding down multiple keys to generate numbers (Army builds smart-phone doctrine).

4) Too big to handle– Big display equals big form factor. Warfighters don’t need to add extra weight to the estimated 130 pounds they are already lugging around. In addition, larger form factors can’t be stuffed into a pocket or held easily in one hand.  A clumsy, hard-to-handle mobile device may be an inconvenience to a civilian, but it could literally be a matter of life or death to a soldier in the middle of a firefight.

While tablets and other form factors with larger displays can be characterized as “too big to carry,” smartphones can be described as “too small to see.”  For video streaming, radar, thermal, and other Situational Awareness applications, bigger is better.   Information, such as landmarks, is lost in the degraded details of a small screen. Maps and geographical data cannot be viewed from the distance on the typical 3.5″ display of a smartphone.

Within each form factor, there are similar issues of portability vs. ease of viewing.  Would a 7″ or 12″ display be better for a combat tablet?  How about a 5″ screen on a smartphone?

What do you think?  In your opinion, what is the best screen size for a combat mobile device?