1. A mobile device for generating a variably displayable keyboard, comprising: a memory device in which instructions are stored for generating two or more groups of basic images, wherein a different keyboard display is generated by each of said groups of basic images so that a surface area of a key generated by a first group of basic images is different from a surface area generated by a second group of basic images; one or more holographic units for presenting each of said two or more groups of basic images; touch screen means transparent to ambient light by which a key of said displayed single group of basic images is selectable and is able to generate an input signal, said touch screen means comprising toggling means for toggling between different keyboard displays; and a microprocessor receiving from said toggling means an activation signal which is indicative of a selected group of basic images, said microprocessor retrieving from said memory device instructions corresponding to said selected group; wherein in response to said retrieved instructions, said microprocessor transmitting data for displaying said selected group of basic images by said one or more hologram projecting units; and said microprocessor receiving said input signal; wherein said transmitted data is indicative of a command for optimally utilizing a surface area of the keyboard display corresponding to the selected group with respect to a mobile device type and key allocation constraints of said selected group, while maximizing a displayed key size; wherein first and second keyboard displays have a same surface area although the surface area of one or more keys is different in the first display than in the second display.