Abstract: A high frequency power source is coupled with a capacitor of a large capacitance. An electric power of the power source is supplied to a plurality of discharge lamps repsectively through lamp load circuits associated therewith. Each load circuit includes a transformer limiting current to the lamp, and a switching means for selectively supplying the electric power from the power source to the lamp, through the transformer. Two types of the switching means, open control type and short control type, are used for the switching means of the discharge load circuit.

Abstract: A discharge lamp comprises a cylindrical lamp casing substantially formed of a metallic material, a transparent glass plate air-tightly fitted to one of the opened end of the lamp casing, a sealing stem air-tightly closing the other opened end of the lamp casing, and a pair of cathode and anode elements sealed in the lamp casing together with discharge gas. The lower portion of the lamp casing may be made in square or circular structure and may be composed of a metallic cylindrical portion extending to a half way of an axial length of the cylindrical lamp casing and a cylindrical transparent glass portion tightly surrounding the outer periphery of the metallic cylindrical portion of the further extending portion and having a front end extending to the sealing stem closing the other end of the lamp casing.

Abstract: A large image display apparatus comprises a plurality of discharge lamps each having an anode, a cathode and a light emitting tube, a display board having the plurality of discharge lamps thereon, a heating circuit for heating the cathodes of the plurality of discharge lamps, a power supply circuit for generating a rectified high frequency voltage and biasing the plurality of discharge lamps, an image signal generator for generating an image signal, and a control circuit for controlling the quantity of light emitted from each discharge lamp in response to the image signal.

Abstract: A large number of luminous display elements are arrayed on a board, and the quantity of light emitted by each display element is controlled in accordance with a video signal generated by a video signal generator. Each display element is constituted by a discharge lamp and a high frequency generator lighting the same.

Abstract: In a picture image display apparatus including a large number of display elements which are lighted by digitalized level adjusted light data produced by a video signal, the digitalized level adjusted light data are corrected by the difference between a mean quantity of light and the light quantity of each luminous element so as to light the luminous element during an interval corresponding to the level adjusted light data without using any light quantity adjusting circuit.

Abstract: An improvement of a plow or a harrow of the type in which a plurality of saucer-like disks carried by a rotary shaft inclined at an angle with respect to the direction of travel of a tractor are forced to rotate, thereby plowing uncultivated farm land. The plurality of disks or disk gang is supported by a parallel linkage system and the angle of the disk gang with respect to the direction of travel of the tractor can be freely selected so that, in accordance with the skill of an operator and soil condition which will be encountered, either the horizontal travel or the inclined travel may be selected.

Abstract: An apparatus for a gaseous discharge lamp includes a power controlling device for converting an AC voltage into a phase control output, a high frequency generating device for converting the output of the high frequency generating device into an high frequency output and a discharge lamp which is lighted by the output of the high frequency generating device and whose filament is heated. The high frequency generating device includes a DC power source for supplying a DC voltage to the power controlling device whenever the power controlling device remains to generate the phase control output. The output of the DC power source heats the filament of the discharge lamp for a period during which no phase control output is produced.