A keyboard system with changeable key displays comprising: - a keyboard having a plurality of keys with transparent housing, the transparent housing having a keycap and a bottom cover to enclose the keycap; - a pressure foot attached to the bottom cover of the key to transfer depression movement when the user depresses the key; - a plurality of display panels each disposed inside the transparent housing of each key, the display panels are capable to display different set of indicia based on control signals triggered by a user; - a first flexible printed circuit board membrane connected to the display panel with a flexible connector, the first PCB membrane receiving data signals relevant to the indicia of the key displays and processing the data signals to be displayed by the display panel; - a key mat with a plurality of bulging protrusions along its upper surface disposed underneath the first PCB membrane, each bulging protrusion extending through the first PCB membrane and disposed between the pressure foot and the first PCB membrane, the bulging protrusions are collapsed when the pressure feet are being depressed; - a second flexible printed circuit board membrane and a third flexible printed circuit board membrane disposed underneath the first PCB membrane with a gap therebetween, whereby when the corresponding key is being depressed, the applied force pushes the pressure foot and causes the bulging protrusions to be collapsed, and electronic circuits of the second PCB membrane and the third PCB membrane are contacted to complete their connection to produce corresponding key output signals; - a system controller connected to the first PCB membrane, the system controller having a digital controller and a memory, the digital controller processing the control signals and retrieving data relevant to indicia from a database stored inside the memory, and the digital controller further sending the data signals to the first PCB membrane; and - a displays controller connected to the system controller allowing the user to change their desired key displays by manipulating the control signals sent to the system controller. - a keyboard having a plurality of keys with transparent housing, the transparent housing having a keycap and a bottom cover to enclose the keycap; - a pressure foot attached to the bottom cover of the key to transfer depression movement when the user depresses the key; - a plurality of display panels each disposed inside the transparent housing of each key, the display panels are capable to display different set of indicia based on control signals triggered by a user; - a first flexible printed circuit board membrane connected to the display panel with a flexible connector, the first PCB membrane receiving data signals relevant to the indicia of the key displays and processing the data signals to be displayed by the display panel; - a key mat with a plurality of bulging protrusions along its upper surface disposed underneath the first PCB membrane, each bulging protrusion extending through the first PCB membrane and disposed between the pressure foot and the first PCB membrane, the bulging protrusions are collapsed when the pressure feet are being depressed; - a second flexible printed circuit board membrane and a third flexible printed circuit board membrane disposed underneath the first PCB membrane with a gap therebetween, whereby when the corresponding key is being depressed, the applied force pushes the pressure foot and causes the bulging protrusions to be collapsed, and electronic circuits of the second PCB membrane and the third PCB membrane are contacted to complete their connection to produce corresponding key output signals; - a system controller connected to the first PCB membrane, the system controller having a digital controller and a memory, the digital controller processing the control signals and retrieving data relevant to indicia from a database stored inside the memory, and the digital controller further sending the data signals to the first PCB membrane; and - a displays controller connected to the system controller allowing the user to change their desired key displays by manipulating the control signals sent to the system controller.