Nec Corporation

Nec Microwave Tube, Ltd.

Shunji Tsuida

Hideo Makishima

Hironori Imura

Wako Suzuki

Provided is a multiprojection display system that includes a plurality of cameras installed in positions in which the cameras can capture images of image-capturing regions including marks whose visible light reflection ratio is higher than the projection region or support members whose ratio to reflect visible light is different from the projection region. An image processing circuit detects prescribed positions and positions of vertexes of projected images from data indicating the images captured by the cameras, and outputs data indicating the detected prescribed positions and image edge data indicating the positions of the vertexes of the projected images. A control unit adjusts, when the Positions of the vertexes of the projected images shift from the prescribed positions corresponding to the vertexes, the positions and sizes of the projected images so that the positions of the vertexes of the projected images can be matched with the prescribed positions.

Multiprojection display system and screen forming method

Provided is a multiprojection display system that includes a plurality of cameras configured to capture images of predetermined vertex regions including vertexes of projected images projected from two-dimensional scanning projectors onto a screen, an image-capturing timing control unit configured to control the cameras to capture images of the screen for a predetermine period including a display. start row of one frame of the projected image or a predetermined period including a display end row, and a vertex position detection unit configured to detect vertexes of the respective projected images from data relating to the plurality of images captured by the cameras, and to output data relating to image edges indicating positions of the vertexes. A projector control unit adjusts, when the vertex of the projected image shifts from a present reference position, a scanning range of the two-dimensional scanning projector so that the vertex can be matched with the reference position.

Electron tube device mounted with a cold cathode and a method of impressing voltages on electrodes of the electron tube device

A method and device are provided for preventing deterioration of a cold cathode in an electron tube device that utilizes the cold cathode as an electron source. In accordance with the expression defining the beam current of the electron tube device, Ib<P&mgr;&times;Va , where P&mgr; represents the perveance of an electron gun and Va represents a voltage impressed upon an accelerating electrode, the electric potential of the accelerating electrode or an adjacent electrode is maintained at the highest level of all electrodes in the electron tube at all times.

A cold-cathode electron gun includes a cold cathode, a conical Wehnelt electrode, and an undercut. The cold cathode has an emitter formed on a substrate to emit electrons,. a gate electrode formed on the substrate through a first insulating film so as to surround a distal end of the emitter, and a focusing electrode formed on the gate electrode through a second insulating film to correspond to the gate electrode. The conical Wehnelt electrode connects the focusing electrode to a first external power supply. The Wehnelt electrode has an opening, at its conical distal end, that comes into with the cold cathode to surround an emitter region including the emitter, gate electrode, and focusing electrode. The undercut is formed in a portion of the Wehnelt electrode which is to come into contact with the focusing electrode to correspond to the gate electrode, thereby forming a non-contact portion.

Field emission type cold-cathode electron gun with focusing electrode

A simply structured cavity resonator for a multi-cavity klystron which can position a movable tuning element at a location where the element should be located with respect to a widthwise direction of the element. The cavity resonator of the multi-cavity klystron includes a cavity envelope, and a movable tuning element slidable on upper and lower internal surfaces of the cavity envelope. Each of left and right internal surfaces of the cavity envelope have continuously formed first and second areas. A spacing between the first areas of the left and right internal surfaces of the cavity envelope is equal to a width of the movable tuning element, while a spacing between the second areas of the left and right internal surfaces of the cavity envelope is larger than the width of the movable tuning element. The second areas correspond go an available frequency band.

Tunable cavity resonator for a multi-cavity klystron

A klystron tuning mechanism includes a tuning element support mechanism, a preset section, a driving mechanism, and a pitch changing section. The tuning element support mechanism is arranged in a cavity resonator to be coupled to a tuning element, fixed in the cavity resonator, through bellows, and axially applies a biasing force to the tuning element. The preset section has a plurality of screw members axially positioned in accordance with preset tuning frequencies and selectively movable coaxially with the tuning element, and a preset plate having an internal thread portion meshed with the screw members. The preset section is retractably moved with respect to the tuning element support mechanism. The driving mechanism drives the preset section to retractably move so as to bring a selected one of the screw members into contact with the tuning element support mechanism against the biasing force, thereby positioning the tuning element to a preset position. The pitch changing section changes part of the pitch of the internal thread portion.

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Tokyo, Japan

Shunji Tsuida