New Nippon Electric Co., Ltd.

Nec Sylvania Corporation

Nec Home Electronics, Inc.

Isao Kaneda

A high intensity discharge (HID) lamp has an arc tube including a pair of main electrodes and at least one auxiliary electrode or probe, wherein a high frequency (HF) high voltage is applied to the probe for forming a high frequency (HF) ignition discharge for establishing a low frequency (LF) arc discharge between the main electrodes. In this ignition system, the electrodes of the arc tube are arranged so that an LF discharge path and an HF discharge path are positioned in an X- or a Y-configuration in the arc tube for causing easy lamp ignition. Also, to simplify the outer leads, it is desirable to mount the probe on one of the main electrodes by a dielectric member opposite another main electrode thereby to form a shorter gap between the probe and the other main electrodes than that between the main electrodes. The starting device of HID lamps has a high frequency-high voltage (HF-HV) generator, the output of which is applied, directly or indirectly, to the probe. Accordingly, sure ignition and hot-restrike can be achieved by applying through the outer leads a superimposed voltage including the source voltage and the HF-HV.

High intensity discharge lamp ignition system

In a discharge lamp lighting system comprising a DC or low frequency (LF) AC main source and a high frequency (HF) source, a high frequency component from the HF source and low frequency component from the main source are supplied in an overlapping manner to the discharge lamp. The HF source of the lighting device is energized by input current from the main source for producing a high frequency current. In addition, the lighting device for the discharge lamp include in combination an HF blocking circuit, an HF passing circuit and/or a matching circuit for the HF source to supply effectively a high frequency component to the discharge lamp, as well as a low frequency component from the main source. In a preferred embodiment, the discharge lamp lighting device includes an HF oscillating circuit for converting an LF component into an HF component and for supplying its intermittent output to the discharge lamp to reignite the discharge lamp at the initial part in each half cycle of the AC source, and to keep the lamp continuously lit.

Discharge lamp lighting device and system

A discharge lamp lighting circuit system comprises a discharge lamp, an intermittent oscillation circuit, and an arrangement for controlling the energy supplied for lighting the discharge lamp with a high power factor. The intermittent oscillation circuit is energized by a low frequency a.c. power supply, i.e. a commercial alternating current power supply, for intermittently generating a high frequency high voltage in each half cycle of the alternating current of the low frequency a.c. power supply. By supplying the low frequency alternating current voltage and the intermittent high frequency high voltage to the lamp the discharge lamp is reignited in each half cycle of the a.c. of the low frequency alternating current power supply and the lit state of the discharge lamp is sustained by the low frequency alternating current voltage. The supplied energy controlling arrangement supplies the low frequency current to the discharge lamp during the operation period of the intermittent oscillation circuit and it also supplies the high frequency current generated by the intermittent oscillation circuit, effectively to the discharge lamp, whereby the discharge lamp is lit with a high power factor.

Circuit system for lighting a discharge lamp or lamps

A parallel circuit of a capacitor and a switching element is connected to a hot cathode discharge lamp lighting device using a high frequency and high voltage generating means for permitting the flow of current into the filaments of the hot cathode type discharge lamp only at the lamp starting time. The switching element of the parallel circuit is a current controlled resistance element, such as a switching semiconductor, having a break-over voltage V.sub.BO lower than the capacitor terminal voltage during the initial ignition period and higher than the capacitor terminal voltage during the reignition or operation period, whereby the filament current to the discharge lamp may be used for preheating of the filament in the initial ignition period. The filament current may be stopped or reduced by turning off of the switching element by raising the terminal voltage of the capacitor in the reignition period during normal operation. Thus, the lumen-per-watt efficacy of the lighting device is improved since the filament current is substantially eliminated during the lamp operation. After the initial ignition period it is preferred to use the capacitor of the parallel circuit as an intermittent commutation capacitor in the high frequency and high voltage generating oscillation circuit having an oscillation capacitor, a nonlinear inductor and a thyristor.

Hot cathode discharge lamp lighting device

A high frequency and high voltage generating circuit for a discharge lamp lighting device controls its initial output at the starting time of a discharge lamp to prevent applying a high voltage to the discharge lamp in the 'cold cathode' state. The circuit comprises in combination an oscillation circuit having an oscillation capacitor, a non-linear inductor and a thyristor, and an initial output limiter for delaying the output supply until the lamp filament is sufficiently preheated for preventing sputtering and for extending the operational life of the discharge lamp. The output control is formed as a bias circuit for the nonlinear inductor and includes a thermistor with a negative or a positive temperature coefficient.

Discharge lamp lighting device with a delayed-output oscillation circuit

A discharge lamp is ignited in every half cycle in its operating system including a discharge lamp operating circuit provided with a low frequency alternating current power source, a single winding type current limiter. The discharge lamp is connected to the power source through the current limiter and a series circuit including a high voltage output generator is connected in parallel to the discharge lamp. The high voltage output generator operates during the lamp operation for reigniting the discharge lamp. The voltage of the low frequency alternating current power source is set to less than the required reignition voltage of the discharge lamp during its operation, whereby the lamp current stabilizer size is minimized. Further, a filament preheating circuit is arranged to use current derived from the high voltage generator. The filament preheating circuit is combined with this operating circuit and so is a time delay for assuring a stable operation.

Discharge lamp operating system

The present discharge lamp system comprises two or more serially connected discharge lamps connected across a pair of power input supply terminals through a ballast circuit and two or more serially connected semiconductor starter circuits. The starters are connected in parallel with their respective discharge lamps and have inherent breakdown voltages, whereby the total value of the breakdown voltages for each starter is higher than the source voltage at the power supply terminals. The system further comprises voltage dividing circuit elements enabling the conduction of one of the starters before the conduction of the other starter or starters in response to the source voltage, whereby the starters operate sequentially. At least one of the starters employs a backswing booster including a series circuit of a nonlinear inductor and a switching semiconductor and a capacitor connected in parallel with the series circuit to provide a sufficient starting voltage for the associated discharge lamp.

Discharge lamp lighting system using series connected starters

A discharge lamp lighting device combines one or more discharge lamps and a backswing booster including essentially a power source circuit having a power source connected in series with a ballast and a high voltage generating circuit having an oscillation capacitor and a series circuit of a nonlinear inductor and a switching semiconductor. The supply voltage for the discharge lamp from the power source circuit is established to the extent permissible by the lower limit for sustaining an arc discharge of the lamp so that the terminal voltage of the ballast in the lamp operation is maintained as low as possible. The preferred backswing booster is of small size and an impedance circuit having a capacitor either with or without a bias coil is added to the high voltage generating circuit to produce a momentary high voltage. A leakage transformer or a voltage transformer with a tap or with a supplemental winding may be coupled to the power source circuit to establish a specified potential point from which voltage for the high voltage generating circuit is supplied to reduce the applied voltage during the lamp operation. An economical lighting device for the sequential ignition of two discharge lamps by means of a single high voltage generating circuit is disclosed.

Discharge lamp lighting device using a backswing booster

It is the purpose of the present discharge lamp lighting system to provide reignition energy to a discharge lamp in each half cycle of the a.c. power source. The discharge lamp is connected to a conventional a.c. power source through ballast means and an oscillation booster circuit, which provides an intermittent oscillation output for the reignition operation of the discharge lamp. The operation period of the intermittent oscillation output is so controlled that the reignition operation period is included in each half cycle of the discharge lamp current. The lamp voltage and source voltage are established to agree as much as possible with each other for minimizing the terminal voltage of the ballast means, whereby a compact and economical device with a small inductance ballast means is achieved.

Arc discharge sustaining circuit system for a discharge lamp

A discharge lamp lighting apparatus includes three oscillation circuits. The first comprises a linear inductor and a capacitor connected in series to a power source. The second oscillation circuit is connected across the capacitor and includes a bounce or backswing booster inductor and a voltage responsive switching element connected in series. The third oscillation circuit comprises the bounce inductor and its distributed capacity. The bounce booster inductor has a magnetic core with a shape and of a material providing an abrupt saturation characteristic. The core factor K of the core is small and may have a ratio of the cross sections of the wound to the unwound parts thereof of less than one half. Alternatively, the ratio of the wound part of the core to the unwound part thereof is less than one fourth and a conventional core material may be employed for the core. Further, the peak temperature characteristic such as the first peak of the initial permeability of the core material may be selected in the range of -40.degree.C to +5.degree.C. The core is provided with a small gap to improve lamp starting operation at high temperatures, the gap having conventional as opposed to mirror polished faces.

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Otsu, Japan

Isao Kaneda