LCD legibility : Standard, outdoor, sun readable
Standard LCD screens are not legible in bright light environments. Specific technologies exist to provide outdoor or sunlight readable LCD screens. He is a simple description
There are 3 aspects in sun readability:
- screen brightness
- operating temperature
As far as outdoor legibility is concerned, there are 3 main types of LCD displays:
1- Standard LCD technology, readable in normal indoor light; they use backlight (fluorescent or LED), they are called transmissive. They are not legible in very bright environmment, not to mention in direct sunlight, because external brightness overwhelms the backlight.
2- Optical bonding : indoor legibility is excellent (unchanged), it is good outdoor in bright light, poor in direct sun light. Optical bonding provides an anti-glare treatment.
3- Transflective LCD : Legibility is excellent in all environments. The outdoor light is reused by the LCD panel to enhance its brightness, without increasing electric consumption. Actual brightness in the sun is higher than indoor. It is necessary to compensate the extremely high brightness in sunny conditions.
High brightness is not efficient outdoor without anti-glare.
Standard indoor electronics is "qualified" up to 35 or 40°C, some LCD or panel PC can be used up to 50 or 60°C.
In any case, to stay in the sun for a long time, 60°C is not enough. Some LCD panels can be used up to 85°C - this option is available up to 17''.
Dark areas appear when LCD panels are used over the expected highest temperature, making them not readable. In most cases, the dark areas disappear when the temperature goes down, but the LCD display is unreadable as long as they remain.