The digital desplay of watches and other devices are normally polarized. What related problem can occur when wearing polarized sunglasses?
When wearing polarized sunglasses, a common problem that can occur with the digital display of watches and other devices is the display appearing faded, dim, or completely blacked out. This happens due to a phenomenon called "cross-polarization."
To explain further, polarized sunglasses work by blocking the horizontally polarized light that reflects off surfaces such as water, roads, or car hoods. The lenses have a polarizing filter that only allows vertically polarized light to pass through, reducing glare and improving visibility.
On the other hand, digital displays like those found on watches, smartphones, and car navigation systems use a special type of polarized film. The liquid crystal displays (LCDs) in these devices transmit light waves that are polarized in a specific direction to create the images we see.
The problem arises when the polarization angle of the sunglasses and the display's polarized film are perpendicular or nearly so. In this case, the sunglasses' polarizing filter can block or severely reduce the light passing through the display, resulting in diminished visibility or complete blackout.
To mitigate this issue, manufacturers often align the polarization angle of their devices' displays at a 45-degree angle or adjust them based on the anticipated usage with sunglasses. However, not all devices are optimized for this compatibility, so visibility problems may persist when wearing polarized sunglasses.
To overcome this problem, you can try tilting your head slightly or adjusting the angle of your sunglasses to find a position where the display becomes visible again. Removing the sunglasses temporarily is also an option, especially if you need to read the display for an extended period.
Additionally, some manufacturers have started incorporating circular polarizers in their devices' displays, which are designed to be less affected by cross-polarization. This can help improve readability even when wearing polarized sunglasses, although it may still vary among different devices and sunglasses.