Patent ID: 6906693

Claim:
A liquid crystal display device having a case internally accommodating a liquid crystal display panel which display an image represented by an applied image signal, said liquid crystal display panel having a display screen exposed externally of the case, said case being formed to include a freely openable and closable light admission window for admitting outside light, and a light guide path being formed for introducing the outside light, which has been admitted by opening said light-admission window, to the back side of said liquid crystal display panel, said liquid crystal display device comprising: a backlight device for projecting backlight toward the back side of said liquid crystal display panel; a setting unit for setting whether to admit outside light from said light-admission window or to project backlight from said backlighting device; a signal correction circuit for subjecting the applied image signal for subjecting the applied image signal to at least one correction selected from the group consisting of a gamma correction, luminance correction, contour correction, hue correction, and color saturation correction to compensate for incident external light directly on the front surface of the liquid crystal display panel for outdoor display in response to a setting by said setting unit for admission of the outside light without projecting back light; a back light control circuit for turning on said backlight device in response to a setting by said setting unit for projection of the backlight; an output circuit for making a connection to an external display unit that displays the image represented by the applied image signal and that is removably attached to the liquid crystal display device; and an output-circuit control unit for turning said output circuit off in response to a setting by said setting unit for admission of outside light.