Abstract: A charger includes a power source device having an outer casing constructed by housing, an upper housing and a side cover, which are formed of metal. Circuit boards and electric components are mounted to the lower housing. An indicator, a coupler resting case and a sensor are mounted on the upper housing. An opening is formed in the upper housing so that wires extending from the indicator and the sensor can be connected to wires extending from the circuit board through the opening of the upper housing, after the upper housing is placed on the lower housing. The opening is closed by a cover and is electromagnetically sealed.

Abstract: Disclosed is a battery gauging device during a battery charging, which is capable of gauging the charged capacity during a battery charging in a terminal. The device according to the invention comprises a charger for converting an AC voltage to a DC voltage, and outputting the converted voltage, a battery pack including a battery for charging an electric charge, first switching means for switching on/off the DC voltage, and second switching means switched on/off in accordance with a battery charge enable (BCE) signal so as to temporarily discharge the charged capacity during the battery charging, and a terminal including a battery gauging section for gauging a charged capacity inputted from the battery pack and a microprocessor for outputting the BCE signal to the switching means, and displaying the gauged value on a display section.

Abstract: This invention relates to an engine stall prevention apparatus for a hybrid vehicle. This engine stall prevention apparatus comprises a clutch operation detection device which detects an operation of a clutch; a clutch state determination device which determines the state of the clutch based on the relationship between the vehicle speed and the engine speed; a throttle opening degree determination device which determines the degree of throttle opening of the engine; a first engine speed modification device (S010) which modifies a charging/regeneration allowing lower limit engine speed value above which deceleration regeneration by the electric motor is allowed; and a half-engaged clutch determination maintaining device (S008) which outputs a determination signal indicating that the clutch is half-engaged for a predetermined period of time when the throttle is completely closed and the clutch is determined to be half-engaged.

Abstract: An electronic component helps realize the miniaturization of an electronic appliance with excellent applicability to a variety of rectification circuits. The electronic component 10 includes within a package FETs 21 and 22, and a switching control integrated circuit 23. Sources and drains of the FETs 21 and 22 are connected to exterior terminals 12a to 12d, respectively, and gates of the FETs 21 and 22 are connected to control signal output terminals 23a and 23b, respectively. An output voltage input terminal 23c, a mode setup signal input terminal 23d, a ground terminal 23e and a power source terminal 23f of the switching control integrated circuit 23 are coupled to the exterior terminals 12e to 12h.

Abstract: An energy management system for a motor vehicle has a first voltage supply terminal having a first nominal voltage and a second voltage supply terminal having a second nominal voltage. At least one of the first and second voltage supply terminals has a battery. A universal bi-directional DC-DC converter is coupled to exchange energy between the first and second voltage supply terminals. A third voltage supply terminal is provided for exchanging energy between the DC-DC converter and an external vehicle electrical system or battery charger. The energy exchanged between the first or second voltage supply terminals and the third voltage supply terminal is independent of the voltage and polarity of the external vehicle electrical system or battery charger.

Abstract: The invention relates to a switched-mode power supplying for a varying load in consecutive cycles of an operation period. Such a varying load may be, for example, a liquid crystal display device. The switched-mode power supply comprises converting means for converting an input voltage into an output voltage and control means arranged to generate a control signal for controlling the converting means. When chip-on-glass technology is used, parasitic resistances may introduce a lag in the output voltage regulation. In order to reduce the lag of the output voltage, the control means comprises memory means for storing status information corresponding to the load level relating to the switching pattern of the converting means in consecutive cycles, and the control means are arranged to generate the control signal from the retrieved status information.

Abstract: A CPU core voltage switching circuit installed in a personal digital assistant wherein, when the personal digital assistant is using an application software product, a CPU clock frequency is reduced to a half of the frequency used when the personal digital assistant is in an initial start state or a memory data initialization state.

Abstract: A reusable miniaturized detector that utilizes magneto-optic elements to detect the occurrence of an electrostatic discharge during the manufacture or handling of electrostatic discharge sensitive electronic components and circuit boards. The device may also be used to determine the polarity and magnitude of the electrostatic discharge. The device may be manually or automatically read, either by removing the device from the environment being monitored or continuously monitoring in situ. The device can also be configured to provide protection to some electrostatic discharge events which could damage sensitive components being monitored.

Abstract: A device for sensing velocity variations in a conductive body 10 moving through a magnetic gap 12 between two discrete portions 13, 14 of a magnetic circuit 15, the magnetic circuit 15 generating a magnetic flux 16 in the gap 12 to induce eddy currents 17 in the body 10 moving therethrough, the device comprising eddy current sensor means 20 defining at least one further gap 24 through which the body 10 is also moved, and at least one sensor coil 18 having a voltage induced therein by variations in the induced eddy currents, said voltage being detectable to provide an indication of variations, that is to say accelerations or decelerations, in the velocity of the moving body 10.

Abstract: The sheet resistance meter has: a coil which produces a magnetic field; a sensor head provided to enable the magnetic field to induce eddy currents in a thin film formed on a substrate so that the lines of a magnetic force exerted by the magnetic field extend on one side of the substrate; a control device for detecting the sheet resistance of the thin film according to a variation of the magnetic field caused by the eddy currents; a capacitor for achieving resonance with the coil; and a groove section, a primary air port, an auxiliary air port, and a side air port, provided in the sensor head, for controlling the temperature of the coil. The arrangement stabilizes results of the measurement of a sheet resistance by a sheet resistance meter of a one-sided eddy current detection type when it is used continuously.

Abstract: A magnetic resonance imaging apparatus applied flip-pulses and gradient magnetic field pulses to generate a plurality of MR signals and to add encoding information to the MR signals, applies pre-pulses to obtain a predetermined effect, and generates an image on the basis of the MR signals. The MR signals include first MR signals arranged in a first region in a k-space and second MR signals arranged in a second region in the k-space. An applying condition for the second MR signals is differed from that for the first MR signals. The applying condition is defined as a ratio of the number of the pre-pulses to the number of the flip-pulses applied in an unit time.

Abstract: A shielding method and apparatus for an antenna disposed on an elongated support adapted for disposal within a borehole. The shield providing predetermined attenuation of one or more electromagnetic energy field components as the field components interact with the shield. The shield composed of a flexible strip or cylindrical body and respectively comprising a transverse conductive element or a transverse slot therein. The shields being adapted to cover an antenna mounted on the support. The shields being compatible for use in conjunction with saddle, tilted coils or multi-layered tri-axial coils to produce a pure transverse magnetic dipole electromagnetic field. The shields are also used in methods for shielding an antenna disposed on a support to provide predetermined attenuation of an electromagnetic field component as the field components interact with the shield.

Abstract: If outputs of a couple of Hall ICs constituting a throttle valve position sensor are within an operating range of throttle valve position, and if a relationship between the outputs are within a predetermined error range, both the Hall ICs are determined to be normal. In contrast, if the outputs are equal to an upper clamp voltage or a lower clamp voltage, and if a relationship between the outputs is out of the predetermined error range, at least one of the Hall ICs is determined to be abnormal. Furthermore, if the outputs are within a failure reference voltage range, it is determined that there is an abnormality between the throttle valve position sensor and an ECU. In this way, abnormalities in the sensor and abnormalities between the sensor and the ECU can also be detected.

Abstract: The invention relates to a electromagnetic method (and an apparatus) for determining the flow rate of a medium in a measuring tube (2), the medium flowing through the measuring tube (2) essentially in the direction of the measuring tube axis (10), a magnetic field permeating the measuring tube (2) essentially perpendicularly to the measuring tube axis (10), a measurement voltage being induced in at least one measuring electrode (3; 4) arranged essentially perpendicularly to the measuring tube axis (10), and the induced measurement voltage yielding information about the volumetric flow of the medium in the measuring tube (2).

Abstract: Hall ICs constituting a redundant throttle valve position sensor are used to measure a rotational angle value indicative of a position of a throttle valve and a temperature value indicative of an ambient temperature change, which is continuously monitored, around the Hall ICs. The rotational angle value measured by the Hall ICs is appropriately adjusted based on the measure temperature value of its own, and a throttle valve position is determined in an externally connected ECU based on the adjusted angle value. In addition, the temperature value measured by one Hall IC is inputted to the ECU. In the ECU, various control values, such as a resistance value of an electric motor, can be appropriately adjusted based on the measured temperature value.

Abstract: A socket and a printed circuit board for testing a semiconductor device packaged by a chip scaled package (CSP) method, and a semiconductor device testing method are provided. In order to test the semiconductor device packaged by a CSP method, the upper wall of the testing socket has a socket aperture formed to expose the pads of the semiconductor device to be tested to the outside of the testing socket. The testing socket may be mounted under the printed circuit board. The printed circuit board has a board aperture formed over the socket aperture. The pads of a semiconductor device are directly probed through both the socket aperture and the board aperture, so that the waveforms of a semiconductor device can be measured.

Abstract: Disclosed herein is a dynamic type circuit which transmits a signal between relatively long-distant circuit blocks lying within a semiconductor integrated circuit chip. A whole signal path thereof comprises a plurality of sections. A section formed by a first type of signal line, which is precharged to a high level and to which a decision as to whether it is driven to a low level according to a signal inputted from a preceding section or it is left in floating state, is made, and a section formed by a second type of signal line, which is precharged to a low level in reverse and to which a decision as to whether it is driven to a high level according to a signal inputted from a preceding section or it is left in a floating state, is made, exist in alternate shifts. The respective sections are respectively connected to preceding-stage sections through MOS transistors for driving signal lines for the sections.

Abstract: A semiconductor integrated circuit device is composed of logic gates each provided with at least two MOS transistors. The logic gates are connected to a first potential point and a second potential point. The semiconductor integrated circuit device includes a current control device connected between the logic gate and the first potential point and/or between the logic gate and the second potential point for controlling a value of a current flowing in the logic gate depending on an operating state of the logic gate. The circuit can be used in devices that cycle in operation between high and low power consumption modes, such as microprocessors that have both an operation mode and a low power back-up or sleep mode used for power reduction.

Abstract: Problems associated with using bipolar differential circuits over a wide common mode voltage range are solved using first and second amplifier circuits 3 and 5, respectively operating over first and second voltage sub-ranges. The low voltage differential signal (LVDS) 1 is applied across a pair of series connected resistors 7 and 9, and to the inputs of the amplifiers 3 and 5. The common mode voltage signal 11 is fed to the inputs of third and fourth amplifiers 15 and 17. The third and fourth amplifiers 15 and 17 ensure that the LVDS receiver has a constant linear transfer characteristic over the differential input signal range and over the full common mode range, especially over the amplifier transition region.

Abstract: A master-slave D type flip-flop circuit includes a power consumption circuit including a reference stage in parallel with a master and a slave stage of the flip-flop circuit. This structure advantageously provides a switching of the flip-flop circuit on each of the leading and trailing edges of the clock signal for the sequencing of the flip-flop circuit.

Abstract: A variable capacitance circuit enables electrostatic capacity to be adjusted as a trimmer capacitor, and that enables a temperature characteristic to be set variably. An input voltage is made to lead by a phase angle of 90° due to a differentiating circuit, before being amplified by an in phase amplifier, thus a current with phase angle of 90° shifted is obtained in such a manner as to take out the output while passing through a resistor. Gain and/or an output resistance of the amplifier are made to set variable. If a thermistor is combined with the circuit as a resistance of the differentiating circuit, temperature coefficient can be made to set variable.

Abstract: A perfect integrator emulator includes a first multiplier multiplying an input with a first constant, KNEW, and generating a scaled input, a summer summing the scaled input with a previously generated scaled output and generating an accumulated output, a delay adding a predetermined amount of delay to the accumulated output and generating a delayed output, a second multiplier multiplying the delayed output with a second constant, KOLD, and generating the scaled output. The constants KNEW and KOLD are chosen such that the accumulated output emulates a perfect integrator's relative weighting, and saturation protection is guaranteed.

Abstract: A predistortion linearizer of a power amplifier capable of improving the nonlinearity of the power amplifier by compensating changes in the power amplifier's nonlinear characteristics according to the lapse of time or an external environment and easily implementing the reverse characteristics of the power amplifier's nonlinear characteristics is disclosed. The predistortion linearizer of the power amplifier as disclosed includes a control unit for controlling a gain and phase of an input signal so that they are the reverse of the power amplifier's nonlinear characteristics, and a unit for compensating changes in the power amplifier's distortion characteristics according to the lapse of time or an external environment, upon receipt of the output of the control unit.

Abstract: A circuit interfacing balanced RF Power Amplifier with unbalanced load has first shunt inductor and series capacitor connected to first output and first shunt capacitor and series inductor connected to second output of amplifier, and comprises second shunt inductor connected to second output and feeding current to this output.

Abstract: There is a manufacturing limit on how small ceramic coaxial resonators can be produced, which leads to a limit on the frequency of resonance for these resonators. One technique to double the effective frequency of a ceramic coaxial resonator is to couple each end of a resonator to a Colpitts oscillator, the oscillators being balanced and out-of-phase by 180°. During operation, the resonator is effectively divided in half with a virtual ground forming in the center. This allows a single resonator to operate as two resonators of half the original size. Hence, the oscillation frequency for each of these balanced oscillators is doubled when compared to the frequency of similar oscillators that have separate ceramic coaxial resonators of similar size. If this technique is further implemented within a push-pull design tuned to the third harmonic, the output oscillation frequency becomes six times that of an oscillator using a separate ceramic coaxial resonator of similar size.

Abstract: The present invention concerns a low frequency oscillator device including a quartz resonator (1) and an electronic maintenance circuit for maintaining the vibrations of said quartz resonator. According to the present invention, the quartz resonator is arranged to vibrate according to a torsional mode and therefore has a single cutting angle defined by a rotation at a determined angle (&thgr;) about the crystallographic axis X of the quartz crystal. This resonator includes in particular at least one undesired fundamental flexural vibrating mode at a first frequency and a desired fundamental torsional vibrating mode at a second frequency higher than said first frequency. Moreover, the electronic maintenance circuit is an inverter circuit (2) whose transconductance value (gm) is determined such that said device cannot oscillate according to the undesired fundamental flexural vibrating mode but according to the desired fundamental torsional vibrating mode of said resonator.

Abstract: The invention relates to a tunable on-chip capacity circuit for a semiconductor chip (10) mounted on a substrate (30) and including a plurality of power supply decoupling capacitors (20-23) which can be selectively activated or deactivated by being switched on or off the power supply system. An on-chip detecting circuit (32) determines a circuit specific load/unload frequency of the on-chip power supply network, and on-chip control means (28, 33) responsive to signals of the detecting circuit increases or decreases the total of the on-chip capacity (CSD) by selectively activating or deactivating power supply decoupling capacitors (20-23). Off-chip path impedances (LMC, RMC), an off-chip capacity (CM) and the total on-chip capacity (CC), including the plurality of power supply decoupling capacitors (20-23) and parasitic on-chip capacities (CP), form a resonance loop (40) which is tunable by changing the total capacity (CSD) of the on-chip power supply decoupling capacitors.

Abstract: A stacked type dielectric filter comprises two sets of resonators arranged in a dielectric substrate constructed by laminating a plurality of dielectric layers, in which each of the resonators includes two resonance electrodes superimposed in a stacking direction; wherein one resonance electrode of the two resonance electrodes for constructing each of the resonators is formed to have a wide width as compared with the other resonance electrode. Accordingly, even when any stacking deviation occurs in the plurality of resonance electrodes during the production, it is possible to decrease the variation of characteristics. Thus, it is possible to maximally exhibit the effect (high Q value, small size, and high performance) to be obtained by constructing the resonator by superimposing the plurality of resonance electrodes in the stacking direction.

Abstract: A double-tuned circuit of a tuner that can be switched for tuning to a plurality of frequency bands by turning a switching diode ON or OFF restrains degradation of a selectivity caused by an undesirable additional tuning circuit or parasitic tuning circuit formed by a capacitance generated when the switching diode is OFF and inter-terminal capacitance of a resistor. A double-tuned circuit of a tuner is also provided that exhibits good selectivity with reduced damping to a tuning circuit in a low-band receiving mode, and also exhibits a wider tuning range. A feed resistor for high-band receiving is directly connected to a switching diode in a primary tuning circuit, and the feed resistor for high-band receiving is connected to a switching diode via a coil in a secondary tuning circuit.

Abstract: An air-wound, coil-type, passive inductor includes a surface which allows the coil to be picked-up using a vacuum probe of a head of a pick-an-place machine and the surface does not interfere with adjusting the spacing between the loops of the coil for tuning the coil after the coil is attached to a circuit board. Terminal ends of the coil are placed on solder paste on interconnection pads on the circuit board, then the board is heated to reflow the solder, and then washed to remove the flux contained in the solder paste. The surface may be adapted to be removed or at least degraded by the heating, or the washing, or afterwards by a mechanical method of removal without damaging the coil.

Abstract: A secure system using a continuously-changing key that depends on the user's body part. A preferred embodiment obtains an image of the user's fingerprint and cements it according to a random generator. Only part of the image and not all of the image is sent at one time. The random segmentation insures that part of the image that is sent continuously varies from time to time. Therefore, an unauthorized receiver can receive only part but not all of the image. That only part of the image which is received will usually not be the same at the second as it is at the first time. Therefore, a received code cannot later be used to fool the system with the same credit card.

Abstract: A command control device is provided for enabling a user to specify or select an address through intuition and with one touch, instead of an address displayed in text form such as a complicated command string or bookmark, which cannot be selected intuitively. An information processing section includes an image capture section, a central processing section, and a command control section. The information processing section carries out a process according to a program stored in a program storage. The information processing section carries out the process first by receiving a user's instruction provided through an input section. Then, the information processing section makes an output section present image display corresponding to command control information stored in a command control information storage. Then, the information processing section executes a command that corresponds to the image display.

Abstract: 1.

Abstract: A method and system for recording acceleration and body position data from elderly or disabled persons. The fall monitoring system includes signal feature extraction and interpretive methods for characterizing accelerations and body positions during fall events. The system can detect health and life threatening fall events in elderly persons, and can autonomously notify nursing personnel or family members that the person is in need of immediate assistance.

Abstract: A mobile object tracking system is provided for tracking the removal and use of specific objects within a group checked out from storage between the time the objects are checked out and the replacement of the objects in the storage. The system includes a system controller and a storage unit that receive and store a series of object carriers therein. Each object carrier includes a series of object holders in which id tags for the group of objects checked out of the storage are received. The object carrier monitors the time each object is removed from the object carrier, which information is thereafter communicated to the system controller.

Abstract: A response-adjustable temperature sensor (306, Rext), particularly for a transponder (102, 200, 400) capable of measuring one or more parameters (e.g., temperature, pressure) and transmitting a data stream (FIGS. 3C, 4B) to an external reader/interrogator (106). The transponder typically operates in a passive mode, deriving its power (Vxx, Vcc, Vdd) from an RF interrogation signal received by an antenna system (210, 410), but can also operate in a battery-powered active mode. The transponder includes memory (238, 438) for storing measurements, calibration data, programmable trim settings (436b), transponder ID and the like.

Abstract: The invention encompasses an electrical apparatus. Such apparatus includes RFID circuitry on a first substrate, and sensor circuitry on a second substrate. A receiving structure is associated with one of the RFID circuitry and the sensor circuitry, and at least one connecting structure is associated with the other of the RFID circuitry and the sensor circuitry. The at least one connecting structure is removable received within the receiving structure. The invention also encompasses a method of forming an electrical apparatus. A first substrate and a second substrate are provided. The first substrate has RFID circuitry thereon, and the second substrate has sensing circuitry thereon. A receptacle is joined with one of the RFID circuitry and the sensor circuitry, and has at least one orifice extending therein. At least one prong is joined with the other of the RFID circuitry and the sensor circuitry.

Abstract: A remote receiver unit is for use in an animal behavior modification system that applies an electrical shock to an animal. The remote receiver unit has an electrical shock device including two electrodes configured for contacting the animal, a source of alternating current voltage, and an electrical transformer with a primary coil and a secondary coil. The primary coil is electrically connected to the source of alternating current voltage. The secondary coil is electrically connected to at least one of the two electrodes. The transformer has an output impedance of less than 900 ohms. A receiver circuit is electrically connected to the shock device. The receiver circuit is configured for activating the shock device in response to a received signal.

Abstract: An apparatus monitors the movement of a person through an exit. The apparatus comprises an electronic article surveillance system adapted to generate an electromagnetic field at the exit and a tag worn by the person. The tag is responsive to the electromagnetic field. It is caused to alarm upon departure of the person from the exit. The tag is further provided with an alarm means for alarming the electronic article surveillance system.

Abstract: The alarm system is capable of detecting both conductive and non-conductive liquid level increases, designed for indoor operation, and ideally suited for detecting basement flooding or leaky domestic steel oil tanks or other fluid containment devices. A float, positioned above any surface such as a contained area (sump or drip pan), rises with the presence of a liquid, allowing a spring-loaded switch to rise, triggering a 9-volt powered battery electric circuit. The electric circuit, enclosed in a plastic enclosure, activates an audible pulsating alarm when triggered. A battery voltage monitor incorporated in the electric circuit, tests the battery voltage on a continuous bases, and will trigger the unit into the alarm mode when the battery voltage is insufficient to sustain continuous operation. A simple convenient self check feature allows the user to simply check the unit at any time.

Abstract: A printer for reporting a printer error state to a user using sound, a control method for the printer, and a data storage medium storing the control method as a computer-readable program use a printing unit (print head 208) that prints text or graphics, a detector (cover open sensor 251, no-paper sensor 252, temperature sensor 253) that detects specific printer error states, and settings memory (RAM 204) that stores a setting determining whether errors are reported using sound. A sound generator (buzzer 231) emits sound when a particular error state is detected by the detector and a setting instructing acoustic error state reports is stored in the settings memory (RAM 204).

Abstract: A communication apparatus automatically sets the most appropriate communication mode in accordance with the location at which the communication apparatus is used. For example, the communication mode is switched between operating as a master station and operating as a remote station of a wireless communication system depending on whether or not connection is made to a wired communication line.

Abstract: A remote control signal from a remote controller (2) is received by one of remote control optical reception parts (4a to 4d), and the respective reception signals are decoded by decoders (11a to 11d). At this moment, the decoders (11a to 11d) extract an address code included in the reception signals received by the remote control optical reception parts (4a to 4d). Based on this address code, an effective-ineffective signal showing effectiveness or ineffectiveness of the decode signal is created. When the effective-ineffective signal shows effectiveness, a decoder selection part (12) adopts a decoder signal of the corresponding decoder.

Abstract: A spin valve magnetoresistive effect type element assessment device includes a head assaying device having a magnetic disk provided with an assaying track where magnetic information is recorded, an oscilloscope for receiving a reproducing signal from an SV head employing an SV element through an amplifier, and a PC for measuring a track profile, namely, data representing relative position dependency of an output from the SV head with respect to the assaying track by controlling the head assaying device and oscilloscope.

Abstract: A CAD data compressing method is disclosed, that comprises the steps of generating a component figure list, and generating data of a plurality of pattern groups each containing a pointer to a component figure of the component figure list.

Abstract: An electric device 100 has a conversion unit 102, and a &Sgr; &Dgr; modulator 106 which functions as a D/A converter is included therein. The electric device 100 inputs an indication signal 40 for requesting a shift to test mode. The electric device testing apparatus 10 has an analog test pattern generator 16 for generating a pattern for testing an analog unit 108 of the electric device 100. The pattern generated herein is a digital signal. Consequently, after it is converted to an analog signal by the &Sgr; &Dgr; modulator 106, a testing process is performed.

Abstract: A device for the unambiguous measurement of the angle of roll of a projectile, comprises at least a radar equipped with means of processing and sending a signal to the casing of the projectile in at least one direction of incident polarization; a set of parallel grooves made on the casing, the depth of which is modulated dissymmetrically with respect to the axis of symmetry of the projectile; the axis of symmetry of the projectile not passing through the point of the antenna of the radar where the antenna beam is generated, the processing means analyzing, in reception, a signal back-scattered by the casing of the projectile, the signal being modulated as a function of the angle of roll of the projectile, the modulation having two maximum local values corresponding to two angular roll positions of the projectile such that the polarization {right arrow over (E)} is parallel to the grooves, the processing means removing the 180° ambiguity by comparing the levels of the local maximum values.

Abstract: Insulating-resin-made attachment part 13A is equipped with connection terminal 10 electrically connected to antenna element 3, and connection terminal 10 is directly connected to a prescribed circuit of a radio machine. As a mounting means to the radio machine, snap part 9 having a metal part projecting out of the sidewall of attachment part 13A is disposed.

Abstract: A broadband partial fan cone direction finding antenna and array disclosed. The antenna includes a radiator having a partial cone shape. The radiator substantially occupies a spatial area defined by a portion of a cone and the cone is defined by a cone axis, a cone height, and a cone angle. The cone has a base and an apex, and the portion of the cone is defined by a cone sweep angle. The cone sweep angle is determined as the angle subtended by a projection of the portion of the cone projected onto a plane that is perpendicular to the cone axis. The cone sweep angle is less than 360° so that the portion of the cone is bounded on its sides by edges which extend radially from the apex of the cone outward to the base of the cone.

Abstract: A PDP that can maintain favorable color balance is provided. In the PDP which is equipped with back phosphor layers of the three colors red, green, and blue in a back panel, front phosphor layers are provided in a front panel respectively in opposition to back phosphor layers other than the back phosphor layer whose luminance degrades fastest with time among the red, green, and blue back phosphor layers. These front phosphor layers are prone to luminance deterioration caused by ultraviolet radiation or ion bombardment, and therefore accelerate the luminance degradation speeds of their opposite back phosphor layers. Accordingly, the luminance of light emitted from each of the two combinations of the front and back phosphor layers is brought to be more balanced with the luminance of light emitted from the back phosphor layer with the highest luminance degradation speed. Hence the PDP can maintain favorable color balance over a long time.