Question
An inkjet printer uses tiny dots of red, green, and blue ink toproduce an image. Assume that the dot separation on the printedpage is the same for all colors. At normal viewing distances, theeye does not resolve the individual dots, regardless of color, sothat the image has a normal look. The wavelengths for red, green,and blue are lambda red = 660 nm,lambda green = 550 nm, andlambda blue = 470 nm. The diameter of thepupil through which light enters the eye is 2.0 mm. For a viewingdistance of 0.35 m, what is the maximumallowable dot separation? s = 1
Explanation / Answer
use rayleighs criterion... . 1.22 = D y /L where y isthe separation. . Note that longer wavelength has larger max separation, so wehave to use the shortest wavelength of 470 nm . and y = 1.22 L / D = 1.22 * 0.35 * 470 x10-9 / .002 = 1.003 x10-4 meters