ABSTRACT
In some situations, illumination is essential to safe product use. Lighting can make people and objects more visible to others in ways that help prevent accidents. Lighting should be sufficiently bright, but not blinding. Integrating lighting into a product can also help people perform tasks more precisely, such as using an electric drill when one’s hand is placed close to the spinning drill bit, or inserting a test strip into a glucose meter’s illuminated slot and reading the test result on a back-lit screen. Normal indoor light levels typically fall in the range of 200-500 lux. Red lighting helps preserve night vision in cases where maintaining night vision is important, such as inside cars, airplanes and submarine control rooms. The eye is relatively insensitive to intensity changes in long-wavelength light, such as red light.
