Discharge lamp starting circuit

A starting circuit for a discharge lamp, comprising:

• a resonance circuit including a series circuit comprising a coil and a first capacitor;
• a discharge lamp connected to the connection of said coil and said capacitor of the series circuit of said resonance circuit so that the voltage between the two terminals of said capacitor of said resonance circuit is applied to the discharge lamp;
• an oscillator circuit for supplying an alternating voltage to said resonance circuit through a driver circuit, said oscillator circuit oscillating at a first frequency around the resonance frequency of said series circuit and at a second frequency different from the first frequency;
• a pulse generator connected to said discharge lamp for supplying pulses having a voltage which is high enough to cause a breakdown in said discharge lamp;
• a detector for detecting a lamp characteristic which can be used to confirm the starting of said discharge lamp;
• and
• a lighting controller for controlling the operating of said discharge lamp by causing said oscillator circuit oscillate at said first frequency when said detector fails to confirm the starting of said lamp and for causing said oscillator circuit to stop after said detector confirms the starting of said lamp;
• further comprising an oscillation controller for controlling said oscillator circuit to oscillate intermittently so that a first period wherein the oscillation is performed and a second period wherein the oscillation is stopped are repeated in turn, and a pulse controller for generating a signal to operate said pulse generator synchronously with the generation of a resonance voltage in response to a signal from said oscillation controller in a period when said oscillator circuit is oscillating;
• wherein said pulse generator has a rectifying circuit for rectifying a voltage of said resonance circuit for supplying said pulses.

A starting circuit for a discharge lamp, comprising:

• a resonance circuit including a series circuit comprising a coil and a first capacitor;
• a discharge lamp connected to the connection of said coil and said capacitor of the series circuit of said resonance circuit so that the voltage between the two terminals of said capacitor of said resonance circuit is applied to the discharge lamp;
• an oscillator circuit for supplying an alternating voltage to said resonance circuit through a driver circuit, said oscillator circuit oscillating at a first frequency around the resonance frequency of said series circuit and at a second frequency different from the first frequency;
• a pulse generator connected to said discharge lamp for supplying pulses having a voltage which is high enough to cause a breakdown in said discharge lamp;
• a detector for detecting a lamp characteristic which can be used to confirm the starting of said discharge lamp;
• and
• a lighting controller for controlling the operating of said discharge lamp by causing said oscillator circuit oscillate at said first frequency when said detector fails to confirm the starting of said lamp and for causing said oscillator circuit to stop after said detector confirms the starting of said lamp;
• further comprising an oscillation controller for controlling said oscillator circuit to oscillate intermittently so that a first period wherein the oscillation is performed and a second period wherein the oscillation is stopped are repeated in turn, and a pulse controller for generating a signal to operate said pulse generator synchronously with the generation of a resonance voltage in response to a signal from said oscillation controller in a period when said oscillator circuit is oscillating;
• wherein said pulse generator has a second capacitor for charging from a voltage generated by a rectifying circuit and a discharge gap connected to said second capacitor for generating said pulses, whereby said voltage supplied to said second capacitor is high enough to cause breakdown in said discharge gap to generate said pulses.

A starting circuit for a discharge lamp, comprising:

• a resonance circuit including a series circuit comprising a coil and a first capacitor;
• a discharge lamp connected to the connection of said coil and said capacitor of the series circuit of said resonance circuit so that the voltage between the two terminals of said capacitor of said resonance circuit is applied to the discharge lamp;
• an oscillator circuit for supplying an alternating voltage to said resonance circuit through a driver circuit, said oscillator circuit oscillating at a first frequency around the resonance frequency of said series circuit and at a second frequency different from the first frequency;
• a pulse generator connected to said discharge lamp for supplying pulses having a voltage which is high enough to cause a breakdown in said discharge lamp;
• a detector for detecting a lamp characteristic which can be used to confirm the starting of said discharge lamp;
• and
• a lighting controller for controlling the operating of said discharge lamp by causing said oscillator circuit oscillate at said first frequency when said detector fails to confirm the starting of said lamp and for causing said oscillator circuit to stop after said detector confirms the starting of said lamp;
• further comprising an oscillation controller for controlling said oscillator circuit to oscillate intermittently so that a first period wherein the oscillation is performed and a second period wherein the oscillation is stopped are repeated in turn, and a pulse controller for generating a signal to operate said pulse generator synchronously with the generation of a resonance voltage in response to a signal from said oscillation controller in a period when said oscillator circuit is oscillating;
• wherein said pulse generator applies said pulses to said discharge lamp via an auxiliary electrode for starting, said auxiliary electrode being set inside an actube of said discharge lamp.