Patent ID: 8344995

Claim:
A portable display device, comprising: a display formed with electronic paper, the electronic paper being configured to display data in response to applied electrical current, and to maintain displaying of the data in an absence of the applied electrical current; an illuminating unit configured to selectively illuminate each particular region of a plurality of regions of the display, the illuminating unit comprising a plurality of light sources which are individually associated with one or more of the plurality of regions of the display; a controller configured to activate the illuminating unit, selectively activating a first group of the plurality of light sources to illuminate a particular region of the display responsive to user contact, wherein the first group comprises at least one of the plurality of light sources; and an illumination sensor configured to detect luminance of ambient light, wherein: the controller is further configured to operate in a nighttime mode in which the illuminating unit is activated, or to operate in a daytime mode in which the illuminating unit is not activated; the illuminating unit is activated based upon the detected luminance such that the nighttime mode is automatically activated when a level of the detected luminance is less than a preset value; and in the daytime mode, the displayed data that is associated with the particular region of the display is distinguished from the displayed data of other regions of the display based upon a different size or color of text of the displayed data.