摘要:
In a lighting apparatus containing a high pressure discharge lamp, an alternating current supplied to the discharge lamp at the time of steady lighting of the frequency (basic frequency) selected from a range between 60 and 1000 Hz and a low frequency having a frequency selected from a range between 5 and 200 Hz lower than the basic frequency is generated alternately. The frequency of the low frequency wave is changed in response to the change of the lighting voltage of the discharge lamp. The supply period of the basic frequency is increased and decreased little by little by every predetermined time.
摘要:
In a lighting apparatus containing a high pressure discharge lamp, an alternating current supplied to the discharge lamp at the time of steady lighting of the frequency (basic frequency) selected from a range between 60 and 1000 Hz and a low frequency having a frequency selected from a range between 5 and 200 Hz lower than the basic frequency is generated alternately. The frequency of the low frequency wave is changed in response to the change of the lighting voltage of the discharge lamp. The supply period of the basic frequency is increased and decreased little by little by every predetermined time.
摘要:
To maintain the shape of the projection on the electrodes of the tip end for a long time to extend the lifetime of a discharge lamp, a lighting device lighting a high pressure discharge lamp supplies alternating current such that an alternating current with a basic frequency at the time of the steady state lighting selected from a range between 60 and 1000 Hz and a low frequency of a half cycle with a frequency lower than the basic frequency are generated alternatingly. The alternating current is supplied such that the waveform with one polarity of the low frequency appears consecutively at least twice. It is also possible for the alternately generated low frequency to be lower than the basic frequency in a range from 5 to 200 Hz, and for the interval during which the basic frequency is supplied to be gradually increased and decreased at specified times.
摘要:
To maintain the shape of the projection on the electrodes of the tip end for a long time to extend the lifetime of a discharge lamp, a lighting device lighting a high pressure discharge lamp supplies alternating current such that an alternating current with a basic frequency at the time of the steady state lighting selected from a range between 60 and 1000 Hz and a low frequency of a half cycle with a frequency lower than the basic frequency are generated alternatingly. The alternating current is supplied such that the waveform with one polarity of the low frequency appears consecutively at least twice. It is also possible for the alternately generated low frequency to be lower than the basic frequency in a range from 5 to 200 Hz, and for the interval during which the basic frequency is supplied to be gradually increased and decreased at specified times.
摘要:
In an optimum frequency detection sequence of a discharge lamp, the frequency control circuit performs a sweep operation in which, while the frequency control circuit monitors a syntonization degree signal, a frequency control signal is changed, so that frequency is changed, starting from either an upper or lower limit frequency of a periodic driving circuit, in a range that does not exceed the other frequency, wherein after completion of the sweep operation, the frequency control circuit determines a value of the frequency control signal corresponding to a resonance frequency of the resonant circuit, and inputs the value into a frequency driving circuit, wherein at least in a period of the sweep operation, an inverter receives power supply from a sweep time power supply circuit for supplying electric power with constant supply capability, which is limited to a range in which breakdown does not occur in the discharge lamp.
摘要:
A discharge lamp lighting apparatus for lighting a discharge lamp, comprises an inverter which reverses a polarity of an output voltage and applies alternating voltage to the discharge lamp, and an inverter control circuit which generates an inverter control signal defining a polarity reversal operation of the inverter, based on a polarity reversal timing signal, wherein when the number of polarity reversals in one cycle of the polarity reversal timing signal is even, the inverter control circuit intermittently performs a first operation in which successive pulse-like part of the polarity reversal operation based on the polarity reversal timing signal is disregarded by odd number of times.
摘要:
A low cost DC—DC converter which facilitates a reduction of the switching loss in a wide, variable range of the continuity ratio of the main switching device includes a direct current source; an ON-OFF-controllable main switching device; a main coil which is series connected to the main switching device; a fly-wheel diode which is arranged such that the induction current of the above described main coil flows when the main switching device is shifted into the OFF state; a smoothing capacitor for smoothing the output of the main coil; an auxiliary coil, a resonant capacitor and an ON-OFF-controllable auxiliary switching device. The main switching device and the auxiliary switching device are controlled such that each are alternatively shifted into the ON state such that the main switching device is shifted into the ON state within a given time after the auxiliary switching device has been shifted into the OFF state.
摘要:
A discharge lamp lighting device having a discharge lamp which has a pair of tungsten-made electrodes each having a protrusion formed at the tip thereof and an electric power feeding device which feeds an alternate current electric power to the discharge lamp, and is characterized in that the power feeding device has a function of switching between a first lighting mode in which a rated electric power is fed to the discharge lamp and a second lighting mode in which a lower electric power than the rated electric power is fed to the discharge lamp to light the discharge lamp, and therefore, can control electric power to be fed to the discharge lamp under such conditions that the average electric power change rate becomes 0.01-2.1 W/s during a mode switching period in which the switching from the first lighting mode into the second lighting mode is carried out.
摘要:
A discharge lamp lighting apparatus for lighting a discharge lamp where a voltage generated in a secondary side winding can be superimposed on an output voltage of an inverter and is impressed between electrodes, where while a periodic drive circuit generates an inverter drive signal so that frequency of the inverter becomes a start-up initial frequency, electric supply control circuit controls a power supply circuit to output no-load opening voltage, where the frequency of the inverter gradually decreases until reaching a first threshold frequency from the start-up initial frequency, where when the frequency of the inverter reaches the first threshold frequency, the periodic drive circuit generates the inverter drive signal so that the frequency of the inverter becomes stable lighting frequency, and where the electric supply control circuit controls the power supply circuit to output current which is sufficient to maintain electric discharge of the discharge lamp.
摘要:
In a discharge lamp lighting apparatus, increase modulation on lamp current with a pulse is carried out according to a modulation signal. At a start-up of the discharge lamp or immediately thereafter, the increase modulation is restrained, and in a lighting steady state of the discharge lamp, the restraining of the increase modulation is released, and wherein when the restraining of the increase modulation is released, in a transition period from immediately after the start-up of the discharge lamp to the lighting steady state, the restraining of increase modulation is gradually released.