Abstract: A passive inductive switch for coupling a battery to a load in a remotely deployed battery-powered electronic device. The switch operates in response to a transmitted magnetic field at a particular frequency. The switch includes an antenna for transforming the magnetic field into an induced voltage and a voltage detector for sensing the induced voltage and triggering a switching element. The switch operates in a standby mode until a sufficient voltage is induced in the antenna which causes the switch to couple the battery to the load. In the standby mode the switch draws a negligible amount of power, which permits the device to be deployed in the field for long periods of time without expending significant battery power.

Abstract: An actuator for positioning of an optical element, such as a mirror, in an optic system that operates under vacuum conditions is provided and includes a first actuator body including a first actuator element that is hermetically sealed in the first actuator body and a second actuator body that includes a second actuator element that is hermetically sealed in the second actuator body. The first and second actuator bodies are hermetically sealed using any number of techniques including a welding process. Moreover, in one embodiment, the actuator operates under the Lorentz principle and the first actuator element is a magnet or magnet assembly and the second actuator element is a coil assembly with the first and second actuator bodies being free of attachment to one another.

Abstract: A permanent magnet (PM) stepping motor includes a rotor structure and a stator. The rotor structure includes an axis, multipolar yoke stacks, and at least one spacer. Each of multipolar yoke stacks includes an N multipolar yoke, a permanent magnet and an S multipolar yoke combined as a hamburger-like structure, and each N pole of the N multipolar yoke and each S pole of the S multipolar yoke are alternately aligned. One of the spacer is sandwiched between each pair of the multipolar yoke stacks. The stator circumnavigates the axis and the multipolar yoke stacks, and provides a magnetic field for the multipolar yoke stacks to make the axis rotating. This PM stepping motor has the advantage of a minimized magnetic pole pitch and a high torque, which cannot be achieved in conventional stepping motors.

Abstract: A small-sized and low-cost stepping motor includes a stator made of a soft magnetic material integrally having first and second outer magnetic poles, a first coil wound around a first bobbin externally fitted to the first outer magnetic pole, a second coil wound around a second bobbin externally fitted to the second outer magnetic pole, and a rotor part made of a soft magnetic material having a magnet fixed around a first column part by interference fit. The rotor part is rotatably supported by a first shaft part of a cover in a hole of the rotor part. An urging member made of a nonmagnetic material is rotatably fitted into the hole of the rotor part, and a compression coil spring urging the rotor part in the axial direction together with the urging member is disposed in the hole.

Abstract: A rotor and a stator are contained in a housing composed of front and rear frames, and a rectifier is mounted on the rear frame and covered with a rear cover having axial and radial openings. A minus heatsink plate having cooling fins extending in the axial direction is disposed to face the radial openings, forming radial air passages, and another air passage is formed between the minus heatsink plate and the rear frame. Cooling air introduced from the radial openings flows through the cooling fins and through the passage between the minus heatsink plate and the rear frame. Thus, efficiency for cooling the rectifier is enhanced.

Abstract: A winding of an electric machine is provided, where the winding includes at least one series of serially connected AC bars. Each AC bar includes a series of serially connected turns formed by litz wire having a plurality of strands, and at least one cooling tube. Individual strands of the plurality of strands are respectively positioned substantially adjacent to the at least one cooling tube at at least one transfer point for providing heat transfer from the respective individual strands to the at least one cooling tube.

Abstract: An anti-loose device for a motor includes a hollow shaft and a motor set. The hollow shaft seat, being provided with a recess and the motor set has an insulation frame, a silicone sheet and a locating member disposed between the insulation frame and the recess. The locating member has an engaging part, a first end part and a second end part and the engaging part is inset the recess with the first and the second end parts resisting the shaft seat and the upper edge of silicone steel sheet respectively so as to generate a function of locating the motor set.

Abstract: A ceiling fan suspended from a mounting rod and comprising a transverse support. A pair of hanging fans are distally mounted on the transverse support. A motor fixed to the mounting rod and spaced radially therefrom drives a gyro gear about an axis parallel to and spaced from the mounting rod. The gyro gear drives a central hub gear about an axis aligned with the mounting rod. The center gear is fixed to the rotatable hub coupled to the transverse support. The fan may be stopped at any point in its rotation and be pointed to direct air flow at a selection location. And the fan may be controlled by a remote control to allow a user to conveniently point the fan at any selected location.

Abstract: In an electric power steering apparatus that generates an auxiliary steering torque by a brushless motor in response to a steering torque applied on a steering wheel and transmits it to an output shaft of a steering mechanism while reducing it by means of a reduction gear, the apparatus comprises a rotor (10) to which a cylindrical permanent magnet for rotational driving (12) and a member to be detected (13) for detection of a rotational angle of the rotor are attached and a cylindrical stator (30) opposed to the rotor in which a laminated core (16) on which a coil is wound, detection means (17) for detecting the rotational angle of the rotor by the member to be detected and a terminal (19) for providing connection to the coil are integrally formed by resin molding. At least one bearing (8, 9) for rotatably supporting the rotor is disposed radially inside the stator and between the permanent magnet for rotational driving and the member to be detected.

Abstract: A motor has a motor unit, an output shaft, a speed-reducing unit for controlling the motor unit, a control circuit board and a gear housing. The speed-reducing unit transmits a rotation of the rotation shaft of the motor unit to the output shaft to rotate slower than the rotation shaft. The gear housing is fixed to the motor unit and includes a generally flat shaped speed-reducing unit receiving portion, which installs at least a part of the speed-reducing unit therein, and a generally flat shaped circuit board receiving portion, which installs the control circuit board therein. The output shaft protrudes beyond and perpendicularly to a side face of the speed-reducing unit receiving portion. The circuit board receiving portion is inclined to the speed-reducing unit receiving portion around a center axis of the rotation shaft to be retracted from an output shaft side of the speed-reducing unit receiving portion.

Abstract: An inner magnet assembly for a rotary magnetic coupling, the inner magnet assembly having an inner ring body with magnet guides, magnets and an overlying sleeve.

Abstract: A permanent magnet rotary motor that can maintain higher torque density and reduce cogging torque more greatly than a conventional permanent magnet rotary motor. A pair of end surfaces of each of permanent magnets used for a rotor are substantially parallel to a virtual plane that extends in the radial direction of a rotor core while passing through the centers of a stator core and an arc surface. Then, the length of the arc surface in the peripheral direction of a rotor core and inclinations of inclined surfaces are so determined that a pole arc ratio ?1 of the arc surface and a pole arc ratio ?2 of a magnetic pole surface in each permanent magnet satisfy the relation of P/2N??2??1?1.38×P/2N.

Abstract: The invention relates to a rotor for an electric motor, particularly an electric line-start motor, comprising axially accommodating spaces (4 to 6) for conductor rods, and axially extending receiving spaces (10, 11) for permanent magnets (14, 15), which are-designed and located in such a way that they generate a permanent magnet field with a magnet axis (22) and a neutral axis (23). The aim of the invention is to ensure that the rotor runs as regularly as possible during the operation of the electric motor. To this end, the diameter of the rotor along the magnet axis is larger than that along the neutral axis (23).

Abstract: A synchronous motor includes a stator, a rotor and permanent magnets. The rotor includes a rotor iron core that is rotatable relative to the stator, and a plurality of conductor bars accommodated within corresponding slots in the rotor iron core. The conductor bars have their opposite ends shortcircuited by respective shortcircuit rings to form a starter cage conductor. The rotor also has a plurality of magnet retaining slots defined therein at a location on an inner side of the conductor bars, in which hole permanent magnets are embedded.

Abstract: An electrical machine including a rotor rotatable about an axis and a stator adapted to magnetically interact with the rotor. The stator including (t) teeth and one or more windings with compact coils disposed around the teeth. The one or more windings having (m) phases and (p) poles, where (t) is an integer and is greater than or equal to two, where (m) is an integer and is greater than or equal to two, where (p) is an integer, is greater than or equal to two, and is an even number, and where (t/p=m/2) or (t/p=m/4).

Abstract: A stator for an electric motor having a stator core which has a number of stator teeth and stator slots located between the stator teeth, the stator slots being designed to receive stator windings, the stator slots being given different depths in order to accommodate the portions of the stator windings of one phase or several phases of the electric motor respectively.

Abstract: A torque motor having an annular rotor and an annular stator. The stator includes a stator frame with iron cores and electrical windings arranged thereon. The iron cores and the electrical windings are arranged in at least one independent stator segment so that each stator segment is independently operable. Each stator segment has its own housing, in which the segment's iron core and the segment's electrical winding are installed. Each stator segment is configured to occupy a predetermined angular segment ?180° in the stator frame. Each stator segment is detachably joined to the stator frame so that the segment can be installed and removed independently of other stator segments without damaging its electrical winding or the stator frame.

Abstract: A piezoelectric vibrator comprising: a thin rectangular piezoelectric plate formed of a material having a Young's modulus having two short edge surfaces and two long edge surfaces and two large planar face surfaces which plate has transverse resonant vibration modes parallel to its short edges and longitudinal resonant vibration modes parallel to its long edges and is formed with at least one cavity; and at least one electrode on each of the planar surfaces that is electrifiable to excite at least one vibration mode of the plate, wherein the at least one cavity is not filled with a material having a Young's modulus substantially equal to the Young's modulus of the material from which the plate is formed, such that the presence of the at least one cavity shifts a resonant frequency of at least one vibration mode of the plate with respect to the resonant frequency that characterizes the at least one vibration mode in the absence of the at least one cavity.

Abstract: There are provided a control apparatus for a vibration type actuator and a control method thereof, which are capable of efficiently driving the vibration type actuator regardless of changes in characteristic of the vibration type actuator, in load, and in characteristic of a circuit for generating a periodic signal, thereby minimizing power consumption. The control method includes the steps of detecting a vibration state of an elastic member in the actuator, detecting a phase difference between the periodic signal applied to the actuator or a signal for generating the periodic signal and a detection signal indicating the vibration state, and controlling the frequency and voltage of the periodic signal. The controlling step includes controlling the voltage of the periodic signal based on the detected phase difference.

Abstract: A method for controlling power supply in a buffered modulation mode is to control an inverter to perform energy transformation so that the inverter and a load in the rear end can function in a reliable characteristic range and prevent the load from aging too quickly. The method includes entering a total energy control regulation signal to an input end of an energy/time ratio synthesizing control unit to get an ON_OFF (High-Low) control sequence on output ends thereof, and adding a regulation energy of varying amplitudes during the ON-Time in the burst period of two ON_OFF cycles to prevent the excitation dynamical ratio of the inverter from being excessively large thereby to prevent the load from aging too quickly.

Abstract: The present invention relates to the field of battery and capacitor charging. In particular, the present invention provides pulsed current charging using changes, regardless of polarity, in the local energy environment to obtain power. The present invention relates, for example, to ambient energy charging thin film batteries, other batteries, or capacitors, via, for example, polyvinyladine fluoride homopolymer (PVDF), PVDF bi-axially poled, or other piezoelectric materials. Ambient energy may be defined as any change in energy within the local environment. Charging can be accomplished with, and is not limited to, positive or negative changes of the following energy types: thermal; visible light, including infrared and ultraviolet; mechanical motion or impact; triboelectric, including airflow or physical contact; movement in relation to a gravitational plane (increase or decrease in gravitational potential energy); and radio frequency (RF) electromagnetic energy, regardless of specific frequency.

Abstract: A piezoelectric/electrostrictive device includes: a ceramic substrate having a frame-like thick portion, a thin diaphragm portion, and a cavity formed by the thick portion and the thin diaphragm portion to communicate with the outside; and a piezoelectric/electrostrictive element having a layered structure including a lower electrode, a piezoelectric/electrostrictive film, and an upper electrode. Furthermore, the thin diaphragm portion is provided with an outward protruding arch shape, and in the piezoelectric/electrostrictive element, there remains a tensile stress parallel to a fixed surface of the element to the thin diaphragm portion. The piezoelectric/electrostrictive device is superior in response, and in the device high-precision (high-resolution, high-sensitivity) detection is possible, while effectively preventing decay of vibration of a thin diaphragm portion and maintaining displacement (amplitude) to be high.

Abstract: A piezoelectric actuator module having at least one piezoelectric component, one actuator foot, and one actuator head is surrounded by an axially extending bush. For sealing the piezoelectric actuator module in the axial direction, the actuator foot is adjoined by a diaphragm, which extends essentially in the radial direction, is joined to the bush, and has a cross section with various radii of curvature.

Abstract: A thin film piezoelectric element has a laminate including a piezoelectric film and a pair of electrode films placed so as to sandwich the piezoelectric film in between, a resin film formed so as to cover the laminate, and an electrode formed on the resin film and electrically connected to the electrode film. The resin film is formed so that a thickness of a region where the electrode is formed is larger than a thickness of a region corresponding to a displaced portion of the laminate.

Abstract: An actuator, comprising a beam (2) including a laminated structure which has piezoelectric layers (30, 31, 32) and electrode layers (20, 21, 22, 23), a holding mechanism to hold the beam, a feeding terminal (10) to supply an exciting power to the electrode layers of the beam, and a contact mechanism provided in the holding mechanism, the holding mechanism comprising a case (1) including a space (5) to house the beam (2) and a holding part to hold at least one of an end and a central portion of the beam (2), the contact mechanism being configured to contact with a part of the beam (2) and prevent the beam from excessively deflecting when a great impact is added to the beam.

Abstract: A piezoelectric structure receives input from a voltage source to generate polarization and output voltage. Two surfaces are formed on the direction normal to the polarized direction. One surface has an input electrode electrically connecting to the voltage source and an output electrode to output voltage. Another surface has a ground electrode. The distance between the input electrode and the ground electrode is different from the distance between the output electrode and the ground electrode. Through the height difference of the two electrodes, the step-up and step-down ratio can be altered.

Abstract: A stacked type electromechanical energy conversion element which is compact in size and capable of providing higher output power and enhanced operating efficiency. A plurality of electrode layers are formed, respectively, on one surfaces of a plurality of piezoelectric layers, and the material layers and said electrode layers are stacked one upon another. Electrodes are formed at least in the plurality of material layers for providing electrical connections between corresponding ones of the plurality of electrode layers. The plurality of electrode layers have a non-uniform configuration depending on a predetermined strain distribution that is to occur in the stacked type electromechanical energy conversion element.

Abstract: An organic light emitting diode (OLED) display includes a substrate defined with a plurality of pixel areas, a heating circuit structure disposed on the substrate, and a plurality of OLEDs corresponding to each pixel area. The heating circuit structure includes two conductive lines not connected to each other, a plurality of heating lines electrically connected to the two conductive lines and covering portions of each pixel areas, and a ground electrode.

Abstract: Electron multipliers, radiation detectors, and methods of making the multipliers and detectors are described. In some embodiments an electron multiplier has a structure including a plurality of interconnected fibers having electron-emissive surfaces, the fibers having a width to thickness aspect ratio greater than one.

Abstract: A spark plug according to the invention includes a metal shell that has a threaded portion with an outer diameter of 10 mm or less, or equal to 12 mm, an insulator, a center electrode, and a ground electrode. The spark plug has an improved structure in which an end portion of the insulator tapers toward an end thereof that protrudes from an end of the metal shell, and dimensional parameters, including a space G of the spark gap in the spark plug, a taper degree of the end portion of the insulator that is represented by an outer diameter difference (D?D0) in the end portion, and a size T0 of the air pocket formed in the spark plug, each have an effective range determined based on the experimental investigation results from the inventors. The structure ensures high insulation properties and high ignition capability of the spark plug.

Abstract: A cathode ray tube comprises a panel having a fluorescent screen on an inner surface; a funnel connected to the panel, an electron gun housed in the funnel; emitting electron beams; and a shadow mask for selecting colors of the electron beams emitted from the electron gun, wherein the deflection yoke comprises a deflection coil for deflecting the electron beams in horizontal and vertical directions, a holder for insulating the deflection coil, and a ferrite core for reducing a magnetic field generated by the deflection coil, and an opening is formed on a flange portion of an opening section on a screen side of the deflection coil.

Abstract: A flat-type fluorescent lamp device includes first and second substrates facing each other, a plurality of first electrodes on the first substrate disposed along a first direction, each first electrode having protrusions extending from both sides of the first electrode along the first direction, a plurality of second electrodes on the first substrate, the second electrodes each having concave portions that correspond to the protrusions of the first electrode and convex portions that correspond to regions between the protrusions of the first electrode, a first fluorescent layer on an entire surface of the first substrate including the first and second electrodes, and a second fluorescent layer on the second substrate.

Abstract: A plasma display device comprises blue phosphor which restricts adsorption of water and hydrocarbon gases to a surface thereof, reduces degradation of luminance and chromaticity change, and improves discharge characteristic. Among phosphor layers used for a plasma display, a blue phosphor layer comprises one of compounds symbolized by Ba1-xMgAl10O17:Eux and Ba1-x-ySryMgAl10O17:Eux, of which phosphor contains 0.2 to 0.8 in number x of Eu atoms, and the Eu atoms comprises 25% to 85% concentration of bivalent Eu ions, and 15% to 75% concentration of trivalent Eu ions.

Abstract: The inventive white-light emitting luminescent conversion LED uses a chlorosilicate luminous substance which is doped with europium in addition to containing Ca and Mg and a garnet rare-earth substance, especially Y and/or Tb. This results in high quality color reproduction and highly constant lighting properties at various temperatures.

Abstract: Various OLED display and device structures are disclosed which reduce shorting.

Abstract: There is disclosed an organic electro luminescence display device that is adaptive for preventing the deterioration of its light emitting efficiency and picture quality, and a fabricating method thereof. An organic electro luminescence display device that is adaptive for preventing the deterioration of its light emitting efficiency and picture quality, and a fabricating method thereof are provided. The organic electro luminescence display device as embodied includes an organic electro luminescence array having first and second electrodes formed on a substrate with an organic light emitting layer therebetween, and a barrier rib in parallel to any one of the first and second electrodes; a protective barrier rib formed to enclose the organic electro luminescence array; and at least one dummy barrier rib located inside a corner area of the protective barrier rib and formed to be bent along the protective barrier rib.

Abstract: A plasma display panel includes a first substrate and a second substrate opposing one another with a predetermined gap therebetween. Address electrodes are formed on the first substrate. Also, barrier ribs are mounted in the gap between the first substrate and the second substrate, and define discharge cells in a predetermined display region of the first and second substrates. Phosphor layers are formed in the discharge cells. Further, scanning electrodes and display electrodes are formed on the second substrate. The scanning electrodes and the display electrodes each have a pitch in the display region that is identical to a pitch in terminal regions, which are formed to the outside of the display region.

Abstract: A plasma display panel with reinforcing electrodes arranged at both ends of discharge cells along a direction address electrodes are formed and coupled to display electrodes. The reinforcing electrodes may comprise carbon-based material such as carbon nanotubes or graphite, and they may be stacked in two or more layers and covered with a dielectric layer and a protective layer. The dielectric layer may be interposed between the reinforcing electrodes and the display electrodes. The dielectric layer may expose the reinforcing electrodes so that the protective layer covers the reinforcing electrodes. A portion of the protective layer corresponding to the reinforcing electrodes has a surface roughness of about 300 nm to about 700 nm.

Abstract: A plasma display panel includes plural discharge cells and a barrier rib layer which defines the discharge cells. Each discharge cells has two opposing electrodes on front and rear substrates, respectively, for generating discharge therebetween, discharge gas and phosphor films. The barrier rib layer is fabricated as a sheet separate from the substrates, is provided with openings each forming a discharge space, and is sandwiched between the substrates. The following relationships are satisfied: 0.1?S2/S1?0.4; 100 Torr ×mm?pd?400 Torr×mm; and 0.2 mm?d, where S1 is an area of a projection of a space occupied by one discharge cell onto the front substrate, S2 is an area of a portion of the front substrate for projecting light from the discharge cell, p is a pressure of the discharge gas, and d is a distance between the electrodes.

Abstract: The invention relates to a lamp for a vehicle headlight with low-beam function, which lamp has an outer envelope and emits at least visible light of different colors from several regions of the outer envelope, characterized in that in that a partial coating is at least provided on the outer envelope such that, when the low-beam function is being realized, at least that region of the traffic space which lies above the bright-dark cut-off can be at least partly illuminated with visible colored light which is scattered at said partial coating, while at the same time that region of the traffic space which lies below the bright-dark cut-off can be illuminated with visible light of a different color in defined regions.

Abstract: A magnetic field compensation winding arrangement for a cathode ray tube includes a magnetic field compensation winding positioned on the cathode ray tube to compensate for an ambient magnetic field. An operational amplifier is used for generating a magnetic field compensation current in the winding. A pair of digital-to-analog converters are used for generating a pair of signals, respectively, that are coupled to the amplifier to control the magnetic field compensation current.

Abstract: An apparatus for detecting the reconnection of a lamp filament to an electronic ballast driving a fluorescent lamp. A control circuit controls an inverter circuit to providing power to a filament control circuit. The filament control circuit preheats and powers the lamp filament of the one or more lamps. A pulse generator generates an input signal as a function of the number of lamp filament connected to the filament control circuit. A current sensor generates a first voltage indicative of whether a lamp filament has been reconnected to the circuit. A peak detector generates a peak voltage signal when the first voltage indicates a reconnection of a lamp filament has occurred. A sensing circuit generates a command signal to provide to the control circuit to supply power to the filament control circuit to preheat and power the lamp when the peak detector generates the peak voltage signal.

Abstract: A method for operating a semiconductor processing apparatus that plasma-processes a semiconductor wafer mounted on a stage placed in a container using a plasma generated therein. The method includes setting a temperature of the semiconductor wafer, and controlling an operation of the semiconductor processing apparatus based on information about the temperature of the semiconductor wafer which is set.

Abstract: A charged particle source utilizes a novel plasma processing chamber, RF coil and ion optics, to achieve high uniformity. The plasma processing chamber has a re-entrant vessel which is movable, and which includes extensions of adjustable shape or position, to make more uniform the plasma contained within the chamber. One or more magnets, which may be static or moving, may be included within the re-entrant vessel. The ion optics include a grid with a number of apertures, and tuning features each surrounding an aperture. These tuning features either reduce the diameter of the associated aperture, or increase the length of that aperture, to create more uniform beamlets emerging from the grid. The RF coil includes a flux concentrator positioned adjacent to the winding in at least one angular region thereof to tune the magnetic field produced thereby.

Abstract: An apparatus for producing light includes a chamber that has a plasma discharge region and that contains an ionizable medium. The apparatus also includes a magnetic core that surrounds a portion of the plasma discharge region. The apparatus also includes a pulse power system for providing at least one pulse of energy to the magnetic core for delivering power to a plasma formed in the plasma discharge region. The plasma has a localized high intensity zone.

Abstract: A light-emitting device includes a plurality of light-emitting elements, particularly three light-emitting diodes and one phototransistor, and acquires excellent white color characteristics. A plurality of light-emitting elements and one light-detecting element are provided onto a substrate. Particularly, one each light-emitting elements for emitting each of first, second and third color is provided and one light-detecting element detects light emitted from each of the light-emitting elements.

Abstract: A method for driving an organic light emitting display panel including a plurality of organic light emitting diode which are coupled to a plurality of segment lines and a plurality of common lines in a matrix structure comprises the steps of: (A) precharging a first organic light emitting diode connected to a first common line and a second organic light emitting diode connected to a second common line, wherein the first common line neighbors on the second common line; (B) supplying a first driving current to the first organic light emitting diode; (C) supplying a second driving current to the second organic light emitting diode; and (D) discharging electrified charge of the first and second organic light emitting diodes.

Abstract: A plasma display panel of an AC 3-electrode plane discharge type includes a front substrate and a back substrate. A plurality of sets of plane discharge electrodes are formed on the front substrate to extend to a row direction, and a plurality of address electrodes formed on the back substrate to extend a column direction. A plurality of row separation walls are formed on the back substrate and the plurality of address electrodes to extend in the row direction, and a plurality of column separation walls are formed on the back substrate to extend in the column direction. A plurality of discharge cells are arranged in matrix.

Abstract: An apparatus for powering a lamp connected to a ballast circuit. A DC bus provides a DC voltage signal to an inverter. A control circuit selectively energizes the inverter to generate an AC signal for powering the lamp load via the rectifier circuit and an inverter circuit. A detection circuit connected between the lamp and inverter generates a detection signal indicating whether an arc condition is present in the circuit. The detection circuit also senses the magnitude of the detection signal and generates a command signal to provide to the control circuit to inhibit power from being supplied to the lamp during an arc condition. A switching circuit is coupled between the output of the detection circuit and circuit ground and responsive to an ignition signal from the control circuit to direct the detection signal to ground during an ignition period.

Abstract: A lamp driving apparatus of a liquid crystal display device includes m lamp groups in which a plurality of lamps generating light are disposed; n (n<m) inverter parts to generate an AC voltage for driving the lamps; an inverter controller to control the inverter parts; and a multiplexer to selectively supply the AC voltage generated at the n inverter parts to the n lamp groups among the m lamp groups. In each frame, a clock signal is divided into n divided signals. Different sets of lamp groups are driven during each of the divided signals.