Display visibility and brightness in outdoor lighting

26 Oct 2022

Each generation of our rugged handheld computer models is designed with the best available display technology for outdoor visibility and function. Available display technologies have improved over time, as is visible in the latest generation of our products.

For additional information, see Four Display Factors to Consider When Choosing a Rugged Tablet for Outdoor Work.

Although NIT ratings measured in candela (one candlepower) per square meter (1cd/m²) are commonly used to compare device displays, they are not good measures of how viewable the display is in an outdoor setting. Luminance is not a measurement of display viewability, it only measures how much light is being emitted by the display. A display that has a highly measurable brightness can still provide a poor outdoor viewing experience due to the display technology and/or bonding process. Similarly, you can have a display technology, such as e-ink, with no measurable brightness that is highly visible outdoors. 

Since there is no industry standard for measuring and communicating display luminance, it is difficult to confidently compare values obtained. To obtain values worthy of comparison, each test of luminance would need to be conducted by the same person.

We provide the following range of values to acknowledge variation in luminance that occurs across the display, between displays, and due to aging of the display. These measurements were taken with the displays tested set to maximum brightness. In our testing. Mesa Pro displays measured between 800–956 cd/m². Mesa 3 revision 6 displays measured between 600-1000 (800 typical) cd/m². Revision 5 and previous displays measured between 350–785 cd/m². The original Mesa 2 displays measured between 450–590 cd/m².

Some specific conditions can potentially cause the display to be less visible than normal. Such conditions can include (but may not be limited to) the following.

• Display backlight and/or contrast is dim (particularly with transmissive instead of transflective displays). You may be able to manually adjust this setting to improve visibility.
• Tactical Mode may be enabled and needs to be disabled.
• Screen protector sheet is installed over the display. Crystal clear (glossy finish) protectors may cause reflections or glare, while anti-glare (matte finish) protectors may allow less light to and from the display. Removing or swapping the screen protector may help.
• Wearing polarized sunglasses (particularly when the polarization of the glasses aligns with the polarization of the display). Switching to different or non-polarized sunglasses may help. The display of the Mesa 3 and later Mesa 2 units work well with polarized sunglasses, or a polarized screen protector sheet may also be available, such as we provide for earlier Mesa 2 units.
• The display controller is not behaving properly, requiring a Hard Reset (hold the Power button for a full count of 20 seconds) or extended power removal (pull battery pack(s) and wall charger for at least 20 minutes).
• The display is damaged (such as extensive scratches), partially disconnected, or has a defect requiring repair or replacement.