Although the display viewing angle is measured objectively, assessing it can be quite subjective. Whether or not a display can be read from a specific angle can depend on the light levels, the size of the text or graphics being viewed and the operator’s eyesight.
With a handheld unit, generally, the operator will move the instrument so that they can clearly read the display. With a bench unit, they may be forced to view the display from an awkward angle, looking at the instrument from the side or from above. When we work with customers on this issue, we always try to understand how the equipment will be used and where the operator will be sitting.
What technology offers the best viewing angle?
The best way to achieve a better viewing angle is to use an IPS display such as a 2.8” portrait TFT. These displays offer a 70-85° viewing angle from all four directions. This is much better, and they can be used in either orientation without penalty. IPS technology offers a lot of other advantages too – better contrast, a deeper black, and a very sharp image. It really is a great looking display technology as you can see in the video below showing the difference in viewing angle between an IPS and a TN display.
How can I improve the viewing angle on an existing display?
If you’re committed to a standard TN such as our 2.8” portrait TFT there are still a number of things that you can do. A recently introduced technology is polarising o-film that redirects light improving viewing angles. Applying o-film gives you typically an additional 10 degrees of viewability in any direction, at the price of a slight loss of sharpness in the image.
An alternative is to add a ‘moth-eye’ film to the front of the display to reduce reflections which can affect viewability, especially from oblique angles. For best results, this needs to be optically bonded to the display. The optically clear glue used in Optical Bonding prevents cracks in the cover glass and creates one solid part helping the display survive drop tests.
In what another way can I improve the readability of the display?
Optically bonding the cover glass to the front of the display doesn’t strictly speaking increase the viewing angle but it does improve appearance and readability in general. It eliminates the internal reflection between the glass layers in the display by eliminating internal reflection between the layers. This increases display contrast so that it can be read more easily even in bright conditions. Even when switched off, an optically bonded display will appear black rather than a murky grey.
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