Patent ID: 6556258
Filing Date: 2003-04-29
Classification: G02B

Abstract:
A display device comprising:a non light-emitting type display element for controlling the transmission of incident light to display an image, a light radiating unit arranged at the back of the display element for emitting illuminating light toward the display element and reflecting ambient light incident from the front of the display element at a given reflectivity toward the display element, the light radiating unit comprising a light source, a light guide, and at least one reflective film provided on the light guide for reflecting the ambient incident light into the light guide toward the display element, the light guide comprising an incident end face, at at least one end face, for taking in illuminating light from the light source, and a front face made up to a stepwise face, the stepwise face including step faces which become lower stepwise from the side of the incident end face to the other side and step-level-difference faces each of which connects the step faces which are adjacent, each of the step-level-difference faces including an emitting face for emitting the illuminating light projected from the incident end face, and an illumination brightness controller for controlling the intensity of the illuminating light so that the screen brightness of the display element comprising the total of reflected light of the ambient light reflected on the light radiating unit and transmitted light of the illuminating light is set up into a predetermined range according to the reflectivity of the light radiating unit and the environmental illumination of the ambient light radiated from the front of the display element.