# Calculation of display luminance

Joined Feb 22, 2007
53
Hi,

According to this page: “Brightness is generally expressed by a numerical value of nits. A nit is a unit of measurement of luminance, or the intensity of visible light, where one nit is equal to one candela per square meter (CD/M2). The higher number of nits, the brighter the screen. Determining the right brightness for your application is extremely important. Common brightness requirements are 800 to 1,500 nits for indoor displays, and 1,500 to 2,500 nits for indoor displays in direct sunlight. For outdoors, on the other hand, up to 5,000 nits is generally recommended and for those in direct sunlight, 5,000+ nits is recommended.”

According to the datasheet of this Adafruit display, each LED gives, more or less, 200 mcd (that is 0.2 cd per LED). One LED is a 3 mm square (giving 9*10^(-6) m^(2)). That gives us more than 20 000 nits which is four times more than what is recommended above (which to me seems too good be true).

0.2 cd / ( 9*10^(-6) m^(2) ) is approx. 20 000 nits

Does this make sense? Are these calculation correct?

Thank you.

Best regards.