In a discharge lamp driver, a control section is configured to alternately repeat a first period in which an AC current is supplied and a second period in which a DC current is supplied, and when a first drive power lower than a rated power of the discharge lamp is supplied and an accumulated lighting time of the discharge lamp is shorter than a predetermined time, the control section is configured to set the length of the first period to be greater than that in a case where the first drive power is supplied and the accumulated lighting time is equal to or longer than the predetermined time, and set the frequency of the AC current during the first period to be higher than that in the case where the first drive power is supplied and the accumulated lighting time is equal to or longer than the predetermined time.

A discharge lamp drive device includes a discharge lamp driver adapted to supply a drive current to a discharge lamp having a first electrode and a second electrode, a control section adapted to control the discharge lamp driver, and a storage section adapted to store a plurality of drive patterns of the drive current. The control section is configured to select one drive pattern of the plurality of drive patterns based on machine learning, and execute the selected drive pattern. In a case in which a predetermined condition is fulfilled, the control section executes a predetermined drive pattern of the plurality of drive patterns without selecting and executing the drive pattern based on the machine learning.

A discharge lamp drive device includes a discharge lamp driver adapted to supply a drive current to a discharge lamp, a control section adapted to control the discharge lamp driver, and a storage section adapted to store a plurality of drive patterns of the drive current. Each of the drive patterns has a plurality of drive parameters. The plurality of drive patterns includes a first drive pattern and a second drive pattern different from each other in a value of at least one of the plurality of drive parameters. The control section is configured to execute the first drive pattern and the second drive pattern in accordance with at least one of accumulated lighting time of the discharge lamp and an individual of the discharge lamp in a case in which an inter-electrode voltage of the discharge lamp is at a predetermined voltage value.

A discharge lamp drive device includes a discharge lamp driver adapted to supply a drive current to a discharge lamp having a first electrode and a second electrode, a control section adapted to control the discharge lamp driver, and a storage section adapted to store a plurality of drive patterns of the drive current. Each of the plurality of drive patterns has a plurality of drive parameters. The control section executes at least three of the drive patterns in a case in which drive power to be supplied to the discharge lamp is in a predetermined power band, and in a case in which an inter-electrode voltage of the discharge lamp is a predetermined voltage value. Any two of the at least three drive patterns are different from each other in a value of at least one of the plurality of drive parameters.

A discharge lamp drive device includes a discharge lamp driver adapted to supply a drive current to a discharge lamp having a first electrode and a second electrode, a control section adapted to control the discharge lamp driver, and a storage section adapted to store a plurality of drive patterns of the drive current. The control section is adapted to select one drive pattern of the plurality of drive patterns based on machine learning, and execute the selected drive pattern.

A discharge lamp lighting device includes a control unit adapted to control a frequency of the AC electric current supplied to a discharge lamp by a feeding unit, in different manners within a first term and a second term which are alternately repeated, the control unit is adapted to control the frequency of the AC electric current such that, within the first term, the frequency of the AC electric current becomes at least one frequency out of plural set frequencies, and is further adapted to control the frequency of the AC electric current, based on a predetermined frequency and an electric current within the previous first term, such that, within the second term, the frequency of the AC electric current becomes a frequency lower than this predetermined frequency.

According to an aspect of the invention, a discharge lamp driving device includes a discharge lamp driving section, a control section, and a voltage detecting section. The control section is configured to execute a first discharge lamp driving for executing a first control and a second control for supplying a driving current including a direct current and an alternating current to a discharge lamp. In the first discharge lamp driving, the control section executes the first control when the interelectrode voltage is equal to or smaller than a first threshold voltage at predetermined setting timing and executes the second control when the interelectrode voltage is larger than the first threshold voltage at the predetermined setting timing. A rate of the direct current in the second control is larger than a rate of the direct current in the first control.

A projector according to the invention includes a discharge lamp, a cooling section, and a control section. The control section is configured to execute a first cooling control in which a number of revolutions of the cooling section does not depend on an inter-electrode voltage of the discharge lamp and a second cooling control for controlling the cooling section based on first control information indicating a relation between the inter-electrode voltage and the number of revolutions. The number of revolutions in the first cooling control is equal to or smaller than the number of revolutions in the second cooling control. When the inter-electrode voltage is larger than a first voltage value or when a cumulative lighting time of the discharge lamp is larger than a first time, the control section configured to switch the control of the cooling section from the first cooling control to the second cooling control.

A discharge lamp lighting device includes a control unit adapted to control a frequency of the AC electric current supplied to a discharge lamp by a feeding unit, in different manners within a first term and a second term which are alternately repeated, the control unit is adapted to control the frequency of the AC electric current such that, within the first term, the frequency of the AC electric current becomes at least one frequency out of plural set frequencies, and is further adapted to control the frequency of the AC electric current, based on a predetermined frequency and an electric current within the previous first term, such that, within the second term, the frequency of the AC electric current becomes a frequency lower than this predetermined frequency.

A gas discharge lamp includes at least two electrodes arranged in a manner spaced apart with a spacing in a discharge vessel filled with gas. A method of operating a ballast includes applying electrical energy to the electrodes. The ballast provides an electrical electrode current including a ripple current being dependent on an operating frequency of converter. Operating frequency is dependent on a charging time period and a discharging time period for an electrical energy store of the converter. The operating frequency is chosen such that the ripple current in the region of an arc discharge brings about a resonant excitation of the gas, and providing a pause time period between the discharging time periods and the respectively succeeding charging time period, the time duration of which pause time period is chosen such that a sum formed from the time periods attains the period duration corresponding to the operating frequency.