Probably even a less experienced designer knows, that a colour TFT display is usually more attractive and mainly better readable if it has a relatively higher brightness (backlight). That´s a well known fact, but despite this only recently standard displays had a brightness of approx. only 200 Cd/m2. That was fully sufficient for indoor use, however when using at a strong ambient light or even a sunlight, the readability went rapidly down. New more efficient white LEDs enabled construction of substantially more powerful backlight while keeping a low power consumption, that´s why nowadays TFT displays usually feature brightness of approx. 300-400 Cd/m2.
Such displays are already subjectively pleasantly bright and contrast (indoor). And outdoor - let´s say they are usable.
Why is a more powerful backlight necessary for outdoor use?
The answer is relatively simple. Contrast of a display is simply said ratio of a white surface brightness (white pixels) to a black surface brightness. The problem is, that a black surface is never fully black, what in praxis means, that small portion of backlight leaks through (contrast drop in a dark environment). At the same time the black surface also reflects some light portion falling from outside (contrast drop in a strong-light environment). When we realize, that a light intensity outdoor can be in order of magnitude higher then indoor, especially on a direct sunlight, so even in case that a black surface would reflect only 2% of a falling light, the resulting brightness of black pixels will rise significantly. Finally, white to black pixels brightness ratio will substantially fall, what´s a main reason of a poor contrast of TFT displays at a strong ambient light.
A solution of this problem can be a usage of high brightness displays. „Super bright“ TFT displays commonly feature brightness of 600-1000 Cd/m2 (or even more). Company Winstar offers super bright TFT displays in 3,5/4,3/5,7 a 7,0“ sizes with resolution of 320x240 to 1024x600 pixels.
Practically all sizes are available without touch panel, as well as with a touch panel (resistive or capacitive). All are with enhanced operating temperatures range (-20...+70´C) and also available is a 4,3“ type, which besides a high brightness features enhanced viewing angles range (O-film TFT display).
Maybe it´s worth to mention, that if you´re searching for the highest brightness of a display and you can live without a touch panel, in that case you´ll gain 25-35% higher brightness in comparison with the same display with a touch panel.
Overview of available TFT types with a high brightness can be found in this document.
In respect to a wide range of versions and modifications, these type are so far as items upon order. Upon request we´re able to promptly supply you with samples as well as main batches for production and in case of interest also to keep desired types on stock.