What does the brightness of the laser pointer depend on?

Red, green, blue and purple, the apparent brightness of the projector illuminated by the high power laser pointer not only depends on the power and surface reflectivity of the laser, but also depends on the color of the human eye. For example, because the human eye is most sensitive to green light with a wavelength of 520-570nm in the visible spectrum, and has a lower sensitivity to red or blue light, green light of the same wattage is brighter than other colors. The power of the laser pointer is usually measured in milliwatts. In the United States, lasers are classified by the American National Standards Institute and the U.S. Food and Drug Administration (FDA). Visible light power is less than 1 milliwatt (wavelength 400-700 nanometers) laser pointer is the second type (class 2 or class II); 3A class (class 3A or class IIIa) power is between 1 to 5 mW. Laser lasers Class 3B (Class 3B / IIIb) (power 5 to 500 mW) and Class 4 (class 4 / IV) (power greater than 500 mW).