Rugged notebooks and tablets are designed to withstand the challenges associated with harsh and unpredictable environments. Optimized for mobile workforces whose jobs take them out of the office, on the road, and even into battle, these devices connect users with their networks and applications.

The primary downside to these devices is that the slightest amount of sunlight reflection, touchscreen, or non-office lighting conditions creates challenges that wash out the display rendering the image almost unreadable.

Recent improvements in display technology have taken small steps to overcome this limitation. Unfortunately the approach used by most manufacturers has been more “brute force" than sophisticated design. The industry’s ‘brute force’ method calls for simply increasing the display brightness (measured in Nits). By adding additional backlights Nit ratings quickly increased from 250 to 500—and now to an eye-squinting 1,000 Nits.

Displays that incorporate multiple backlights to generate adequate light (1,000 Nits) to overpower direct sunlight are not the ideal solution one might think. While this is an improvement to standard technology the implementation has numerous weaknesses and customer trade offs which need to be considered before selecting a technology for mobile workforces.

Since Nit ratings only measure brightness, they are a poor indicator of display viewability. In the field, users need to be able to distinguish fine details such as text and graphics in order to be effective. Increasing brightness simply does not address the most important technical challenges nor does it indicate whether or not the display is truly viewable in bright sunlight.

Sunlight reflecting off the many layers of the touchscreen and LCD is the primary element that washes out the image making fine detail difficult to distinguish and colors to become muted. Reduce these reflections; both specular, (mirror like) and diffuse, (uneven) and you create a highly viewable display without increasing brightness.

Since Nit ratings are not an indicator of viewability, a more appropriate measurement of outdoor performance must be used. Contrast ratio; specifically high ambient contrast ratio, is used to measure the viewability of displays mounted in military aircraft cockpits and provides a much clearer characterization of viewability.

Measuring contrast ratio determines the level of detail that can be seen on the display, with the higher ratio providing richer color and crisper lineation. Commercial notebooks’ contrast ratio is typically measured indoors under optimal and predictable conditions. Typical indoor or “subdued light” contrast ratios vary from 150:1 to 300: 1 (or higher). In the mobile environment contrast ratio takes on critical importance, as the lighting in vehicle and outdoor environments is not the typical “subdued” office lighting. In an outdoor setting, the light source can come from many angles and be very bright and highly reflective. In this environment “daylight readability” based on DOD-STD-3009 "Lighting, Aircraft, Night Vision Imaging (NVIS) Compatible" is more appropriate and DynaVue® display meets or exceeds this standard.

DOD-STD-3009 provides specifications and guidance for the development of the primary flight displays and mission avionics controls and displays subsystem for aircraft and since the cockpit environment has similar lighting conditions as the outdoor worker, it is the ideal standard for mobile computers.

This DOD standard provides a realistic and easy to replicate measurement method to determine critical factors such as display reflectance and contrast ratio. The measured display performance references have been shown to correlate closely with perceived qualities. A contrast ratio of >3.0:1 is specified as the minimum acceptable level under high ambient (sunlight) illumination conditions. A display with high ambient contrast ratio above 3.0:1 is considered to be acceptable for outdoor viewability. Consumers require a display technology that provides optimum viewability in all lighting conditions. Rather than selecting a notebook display based on Nits alone, a high ambient contrast ratio must be taken into account in the selection process.