Ushio Denki Kabushiki Kaisha

Kosuke Saka

Takashi Yamashita

Kazuhiro Goto

Minoru Fukuda

Shigeyoshi Matsumoto

Shoichi Terada

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.

Discharge lamp lighting device

A discharge lamp lighting apparatus is provided with a pulse generation part, and a power supply part converts DC applied voltage into alternating current corresponding to a frequency of the pulse, and supplies the alternating current to the discharge lamp. The pulse generation part is structured to alternately output a first pulse and a second pulse that has a lower frequency than the first pulse. The frequency of the second pulse is set to a predetermined reference frequency when a value of the applied voltage coincides with a predetermined reference value, is set to a lower frequency than the reference frequency when the value of the applied voltage exceeds the reference value, and is set to a frequency that is equal to or lower than the reference frequency when the value of the applied voltage falls below the reference value.

Discharge lamp lighting apparatus

A high-pressure discharge lamp lighting device is used for projector devices that allow controlling the mean electric power at a desired value with a slow processing speed. A color wheel rotates and disperses the beam from lamp into each of the color components, such that the electric power supplied to the lamp is controlled at different levels for each segment of the color wheel and the power feeding device control part finds the mean electric power by sampling the electric power supplied.

High pressure discharge lamp lighting device

A first energy ratio A/B of a first alternating current of a steady frequency supplied to a lamp is set to a value C, when the lamp is horizontally placed. A second alternating current of a lower frequency, whose second energy ratio A/B is set to the value C, is inserted. When the lamp is vertically placed, a first energy ratio A'/B&#x2032; is set to the value C or a value D, which is smaller than the value C. A second ratio A&#x2032;/B&#x2032; is set to the value D or a value E, which is lower than the value C. A and A&#x2032; each represents an energy that flows from a first electrode of a pair of electrodes of the lamp to a second electrode of the pair. B and B&#x2032; each represents an energy that flows from the second electrode to the first electrode.

Light source apparatus

In a light source apparatus, an alternating current is supplied to a high pressure discharge lamp from a power supply apparatus to light the lamp. The arrangement state of the lamp is detected by a detection circuit. When the lamp is horizontally arranged, electric energy, whose flow direction is from one electrode of the lamp to the other electrode, is set to be approximately the same as electric energy, whose flow direction is from the other electrode to the one electrode. When the lamp is vertically arranged, while a cycle, which is the same as a polarity change cycle in the horizontal arrangement, is maintained, electric energy, which flows from an upper electrode to a lower electrode, is set to be smaller than electric energy, which flows from the lower electrode to the upper electrode.

Growing community of inventors

Hyogo, Japan

Kosuke Saka