the side it is also known to utilize more than one lamp light output from the lamp or lamps is normally spread out evenly over the lcd surface by some form of spreader or diffuser 30 if there is more than one lamp they are always connected in parallel so that the whole lcd surface is evenly illuminated fig2 shows an lcd panel in accordance with the present invention wherein more than one lamp is provided for backlight four lamps 20 are shown in the embodiment of fig2 but the minimum number should be two at least one of the lamps is independently controlled from the others the independently controlled lamp has a separate power line 55 to the battery not shown whereas the other lamps share a power line 50 to the battery the lamps may be electroluminescent panels incandescent sources light emitting diodes or even plasma discharge panels to mention a few examples in accordance with a preferred embodiment of the present invention an application input mode is defined for example by a window icon or a function key as 34 power typing 34 and in this mode three of the backlight lamps are turned off leaving only one lamp to illuminate 1 4 of the lcd screen and hence typically show 10 lines of text to the user it is necessary to tailor the application to synchronize to this mode so that just the bottom ten lines for example of the screen are used until the normal mode is re commanded in accordance.