Abstract: The viewing angle of a liquid crystal display may be controlled by storing a digital code which represents the viewing angle, and converting the stored digital code to an analog voltage which is applied to the bias input of the liquid crystal display. To adjust the viewing angle, a new digital code is stored using keypad input. The invention is particularly suitable for microprocessor controlled displays, and eliminates the need for a hinged or pivoted display, or a viewing angle adjustment knob.

Abstract: A security system includes a display for displaying user prompts to select from a set of alternative options for controlling the system, so that the user may respond by selecting one of the options. If further information is necessary, second and subsequent sets of options are displayed for user selection. If an authorization code is required, a prompt for an authorization code is displayed. The sets of options are preferably displayed adjacent a keypad, so that an option may be selected by actuating the key adjacent the selected option. Sequences of commands need not be memorized by a user, and complicated keyboards are not required to control the security system.