Illumination device and display device using it

Abstract

An illumination device is provided of the type arranged at the front which is of low power consumption and of high recognisability both when the illumination is turned on and when illumination is turned off. An illumination device arranged at the front face of an illuminated object has a light-guide plate forming a transparent flat plate shape and formed with point-form optical extraction structures on its surface or in a position facing this surface, and a light source arranged opposite and end face of this light-guide plate. The light source is for example a point light source. The optical extraction structures are for example pillar-shaped projections and these are arranged two-dimensionally. The function is provided that, when this illumination device is arranged at the front of the illuminated body, rays are projected on to the illuminated body and rays reflected by the illuminated body are transmitted with scarcely any dispersion. There is also provided a function of transmitting external light with scarcely any dispersion of rays reflected by the illuminated body when the illumination is not turned on. A point light source such as a light emitting diode (LED) or electric light bulb can be employed and low power consumption can easily be achieved.