Abstract: The online learning system provides customized answer explanations based upon a user's incorrect response to a multiple choice question. The explanations identify trick answers and how to avoid them, incorrect assumptions, and/or incorrect calculations that caused the student to reach the incorrect solution. The system also tracks the user's progress and provides customized feedback based on measurable aspects of the user's progress. Course material is provided by the system using a video game and/or social gaming type of user interface that fosters competition to motivate students and also uses incentives such as experience points, levels of mastery, and the ability to earn virtual goods or unlock challenges as the user progresses.

Abstract: A heater and support structure for a line cathode includes heater electrodes and an S-shaped cathode support member arranged between the heater electrodes. The heater electrodes and the S-shaped support member have a higher resistance than the cathode and thus heat flows into the cathode to compensate for heat radiation losses and the support compensates for thermal expansion to retain the cathode at a substantially constant position.

Abstract: A cathode for a cathodoluminescent display device includes a plurality of low coefficient of expansion support columns arranged in a substantially parallel spaced relationship, a resistive cathode heater member extends between and is permanently affixed to the support columns. An electron emissive coating is on a portion of the cathode heater member between the columns.

Abstract: Microelectronic, locally-situated circuitry and memories, together with digital displays, are employed for modifying otherwise standard telephone stations so that the telephone stations can be utilized to store digital messages, such as the Caller's telephone number, transmitted by each of a plurality of Callers to an unattended User station. The unattended User station automatically retransmits a received digital message back to the Caller for verification, permitting the Caller to correct any error in the digital message or to send to the User station a verification signal that is also stored. All the stored information is available to the User upon his return, and may be used to automatically dial back the Callers.

Abstract: A support for supporting the line cathode of a flat panel display device is electrically insulative and has low thermal conductivity. The support is U-shaped and has a notch in the closed end for supporting the cathode a precise distance from the entrance to the guide mesh assembly. The support is spring loaded in the guide mesh assembly and is retained by retainer means on the support and in the guide mesh assembly.

Abstract: A flat panel display device is composed of a display section and an electron gun section which provides electron beams for forming a visual display on the display section. A line cathode within the electron gun section serves as the electron source. A plurality of electrode pairs are voltage biased to establish the conditions under which electrons are ejected from the cathode and also to focus electron beams for propagation along the display section.

Abstract: A flat panel display device having a plurality of electron propagation channels utilizes a line cathode. The cathode extends across all the channels and modulation electrodes associated with the channels cause the cathode to emit the electrons into the spaces between parallel guide meshes within the propagation channels. The cathode and modulation electrodes are arranged in a recessed cavity in the proximity of launch electrodes so that the electrons are emitted at high velocity into the propagation channels to travel curved paths along which the electron beams are converged into the spaces between the guide meshes. Electron propagation structure within the channels, therefore, is displaced from the cathode so that the cathode heat has a substantially reduced effect on the propagation structure, and the high electron velocity minimizes the effect of mechanical tolerances on the electron beam.

Abstract: In a flat panel display device including spaced parallel guide meshes between which electron beams propagate, the guide meshes are formed to include projections extending into the electron beam propagation space. The projections restrict the electron propagation space in a direction perpendicular to the planes of the guide meshes and thus capture electrons near the extremities of the space.

Abstract: In a flat panel cathodoluminescent display utilizing a plurality of electron guns a single line cathode is used as the electron source for all guns. Changes in electron beam current resulting from vibration of the line cathode are compensated for by the application of voltages which are related to the current changes. The compensating voltages are applied through an impedance network which relates the voltages in accordance with the envelope of vibration so that the actual compensations at the individual guns are related to the actual current changes at the respective guns.

Abstract: A system for controlling the emission of a device having a sense electrode for sensing a measure of an emission species from a source within the device. The sensed measure of the emission species is converted to a control signal. The output of the source is modified in response to the control signal by varying the time during which the source emits the emission species.

Abstract: The envelope of an image display device has front and rear walls spaced from one another with a cathodoluminescent screen on the front wall. Within the envelope are a plurality of electron beam guides parallel to the rear wall and a source of electrons at one end of the beam guide. Each beam guide has at least one electrode adjacent to and parallel to the rear wall. A plurality of spaced parallel wires arranged in a common plane are between the electrode and the front wall. An electrically conductive mesh is parallel to the plane of wires between the plane and the front wall. The mesh has a plurality of closely spaced apertures which are not greater than 26 microns wide in one dimension.

Abstract: A series of discrete heating current pulses are passed through a line cathode so as to cause the cathode to emit electrons therefrom. Between each consecutive pair of pulses is a cooling period during which no heating current flows through the cathode. Current is extracted from the cathode during this cooling period. In a preferred embodiment for an image display device, the heating pulse duration is about 10 .mu.sec and the cooling period is about 50.mu.sec. In this scheme, the heating period corresponds roughly to the horizontal retrace time between line times of 50.mu.sec.