Various embodiments provide a projection arrangement. The projection arrangement may include a discharge lamp; and a ballast for the discharge lamp. The ballast is designed to provide, during operation of the projection arrangement, a lamp current in the form of alternating current and having an average frequency and a preset waveform, which has a preset commutation scheme, to the discharge lamp. The preset commutation scheme is preset by a preset time sequence of commutations of the lamp current. The ballast is designed to provide the lamp current in such a way that the preset commutation scheme of the lamp current is deviated from repeatedly with at least one preset intervening time period by at least one DC phase with a preset time duration.

A control method of an electronic ballast of a gas discharge lamp (HID), to generate a PWM1 signal for controlling on/off of a left upper arm switch, a PWM2 signal for controlling on/off of a right upper arm switch, a PWM3 signal for controlling on/off of a left lower arm switch, and a PWM4 signal for controlling on/off of a right lower arm switch, the PWM1 signal and the PWM3 signal are low frequency signals and have an identical frequency and an opposite phase, the PWM2 signal and the PWM4 signal are high frequency signals. Duty ratios of PWM signals for controlling arms of a semiconductor full bridge circuit are changed according to a power consumption of the gas discharge lamp (HID) to control the power consumption of the gas discharge lamp (HID).

A control method of an electronic ballast of a gas discharge lamp (HID), to generate a PWM1 signal for controlling on/off of a left upper arm switch, a PWM2 signal for controlling on/off of a right upper arm switch, a PWM3 signal for controlling on/off of a left lower arm switch, and a PWM4 signal for controlling on/off of a right lower arm switch, the PWM1 signal and the PWM3 signal are low frequency signals and have an identical frequency and an opposite phase, the PWM2 signal and the PWM4 signal are high frequency signals. Duty ratios of PWM signals for controlling arms of a semiconductor full bridge circuit are changed according to a power consumption of the gas discharge lamp (HID) to control the power consumption of the gas discharge lamp (HID).

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 configured to supply drive electric current to a discharge lamp having a first electrode and a second electrode, a control unit configured to control the discharge lamp driver; and a storage unit configured to store a plurality of drive patterns of the drive electric current. The control unit is configured to select one drive pattern from among the plurality of drive patterns based on machine learning, and implement the selected drive pattern. The control unit is configured to adjust a drive electric power supplied to the discharge lamp based on illumination level information relating to an illumination level of the discharge lamp, while performing switching among the drive patterns based on the machine learning, in a case where an inter-electrode voltage of the discharge lamp is larger than a given voltage value.

A discharge lamp drive device includes a discharge lamp driver configured to supply drive electric current to a discharge lamp having a first electrode and a second electrode, a control unit configured to control the discharge lamp driver; and a storage unit configured to store a plurality of drive patterns of the drive electric current. The control unit is configured to select one drive pattern from among the plurality of drive patterns based on machine learning, and implement the selected drive pattern. The control unit is configured to adjust a drive electric power supplied to the discharge lamp based on illumination level information relating to an illumination level of the discharge lamp, while performing switching among the drive patterns based on the machine learning, in a case where an inter-electrode voltage of the discharge lamp is larger than a given 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. 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 driver includes a discharge lamp driving unit configured to supply drive current to a discharge lamp and a control unit configured to control the discharge lamp driving unit. The drive current has a modulation drive period in which a first period in which AC current having a frequency higher than 1 kHz is supplied and a second period in which DC current is supplied are alternately repeated. In the modulation drive period, the control unit periodically changes length of a first DC period included in the second periods and in which DC current of a first polarity is supplied, and length of a second DC period included in the second periods and in which DC current of a second polarity is supplied, and increases one of the length of the first DC period and the length of the second DC period while decrease the other one.

This projection-type image display device is provided with: a lamp drive unit that drives a lamp; a lamp voltage detection unit that detects a lamp interelectrode voltage (hereinafter referred to as a lamp voltage); an image correction unit that corrects image qualities of image signals to be supplied to an image display element; and a control unit that controls a correction quantity of the image correction unit on the basis of the lamp voltage detected by means of the lamp voltage detection unit. Consequently, deterioration of visibility of a projection image can be suitably suppressed.

A discharge lamp driver includes a discharge lamp driving unit configured to supply drive current to a discharge lamp and a control unit configured to control the discharge lamp driving unit. The drive current has a modulation drive period in which a first period in which AC current having a frequency higher than 1 kHz is supplied and a second period in which DC current is supplied are alternately repeated. In the modulation drive period, the control unit periodically changes length of a first DC period included in the second periods and in which DC current of a first polarity is supplied, and length of a second DC period included in the second periods and in which DC current of a second polarity is supplied, and increases one of the length of the first DC period and the length of the second DC period while decrease the other one.