Abstract: A discharge lamp includes a glass bulb and a pair of electrodes provided at both ends of the glass bulb. At least one of the electrodes is an external electrode formed on an outer surface of the glass bulb as a thin layer whose maximum thickness is 70 ?m or less, and an end portion of the external electrode becomes smaller in thickness towards an end of the external electrode.

Abstract: A discharge lamp lighting device includes a high frequency power supply for supplying high frequency power to the discharge lamp via a first impedance element, a DC power supply for applying DC voltage to the discharge lamp via a second impedance element, a dimming control circuit for carrying out a dimming of the discharge lamp by controlling the power supplied to the discharge lamp, a DC voltage detection circuit for detecting a DC component of the voltage applied to the discharge lamp, and an output correction unit for making a correction to the power supplied to the discharge lamp in accordance with a value detected by the DC voltage detection circuit. It can light the discharge lamp stably regardless of a variation in temperature.

Abstract: A discharge lamp operation apparatus includes an AC power supply (10), a voltage converting circuit (11), an inverter circuit (13), a load circuit (15), a controller (1), and a pulse voltage superimposing section (3). The pulse voltage superimposing section (3) controls the switching elements (Q3, Q4) of the inverter circuit (13) to superimpose a pulse voltage to the voltage applied across the discharge lamp (LA). The period until the discharge lamp (LA) is lighted is divided into a preheating period to preheat the discharge lamp and a startup period to start the discharge lamp. During the startup period, the controller (1) raises gradually the output voltage (Vdc) of the voltage converting circuit (11), and the voltage superimposing section (3) superimposes the pulse voltage on the voltage applied across the discharge lamp (LA).

Abstract: An electronic ballast for a discharge lamps has a dimming control for varying an input DC voltage and an input driving frequency in combination to achieve a lamp dimming in accordance with a dimmer demand. The ballast includes a dimming processor with a memory for storing a table that gives a predetermined relation between the dimming demand and a voltage command designating the input DC voltage as well as a frequency command designating the input driving frequency. A command processing unit is included in the processor to derive the voltage and frequency commands that matches with the dimmer demand so as to vary the light output of the lamp in accordance with the voltage command and the frequency command, respectively derived from the table.

Abstract: A discharge lamp lighting device includes a high frequency power supply for supplying high frequency power to the discharge lamp via a first impedance element, a DC power supply for applying DC voltage to the discharge lamp via a second impedance element, a dimming control circuit for carrying out a dimming of the discharge lamp by controlling the power supplied to the discharge lamp, a DC voltage detection circuit for detecting a DC component of the voltage applied to the discharge lamp, and an output correction unit for making a correction to the power supplied to the discharge lamp in accordance with a value detected by the DC voltage detection circuit. It can light the discharge lamp stably regardless of a variation in temperature.

Abstract: An electronic ballast for a discharge lamps has a dimming control for varying an input DC voltage and an input driving frequency in combination to achieve a lamp dimming in accordance with a dimmer demand. The ballast includes a dimming processor with a memory for storing a table that gives a predetermined relation between the dimming demand and a voltage command designating the input DC voltage as well as a frequency command designating the input driving frequency. A command processing unit is included in the processor to derive the voltage and frequency commands that matches with the dimmer demand so as to vary the light output of the lamp in accordance with the voltage command and the frequency command, respectively derived from the table.

Abstract: A discharge lamp operation apparatus includes an AC power supply (10), a voltage converting circuit (11), an inverter circuit (13), a load circuit (15), a controller (1), and a pulse voltage superimposing section (3). The pulse voltage superimposing section (3) controls the switching elements (Q3, Q4) of the inverter circuit (13) to superimpose a pulse voltage to the voltage applied across the discharge lamp (LA). The period until the discharge lamp (LA) is lighted is divided into a preheating period to preheat the discharge lamp and a startup period to start the discharge lamp. During the startup period, the controller (1) raises gradually the output voltage (Vdc) of the voltage converting circuit (11), and the voltage superimposing section (3) superimposes the pulse voltage on the voltage applied across the discharge lamp (LA).

Abstract: A discharge lamp driving device capable of detecting a lamp life end reliably in a high or low temperature environment for circuit protection, yet preventing the occurrence of the cataphoresis phenomenon. Impedance elements Z1 and Z1 are inserted respectively between one filament ends of individual discharge lamps La1 and La2 and a node (the ground) having no high frequency amplitude in order to detect a difference between AC components of individual lamp voltages VLa1 and VLa2 in closed loops of the discharge lamps La1 and La2 and the impedance elements Z1 and Z1 in order to judge whether or not the depletion of the emitter occurs. Thus, it is possible to reliably judge the presence of abnormality even when the amplitudes of the lamp voltages VLa1 and VLa2 varies in a range of low to high temperature.

Abstract: A discharge lamp driving device capable of detecting a lamp life end reliably in a high or low temperature environment for circuit protection, yet preventing the occurrence of the cataphoresis phenomenon. Impedance elements Z1 and Z1 are inserted respectively between one filament ends of individual discharge lamps La1 and La2 and a node (the ground) having no high frequency amplitude in order to detect a difference between AC components of individual lamp voltages VLa1 and VLa2 in closed loops of the discharge lamps La1 and La2 and the impedance elements Z1 and Z1 in order to judge whether or not the depletion of the emitter occurs. Thus, it is possible to reliably judge the presence of abnormality even when the amplitudes of the lamp voltages VLa1 and VLa2 varies in a range of low to high temperature.