Discharge lamp driving device, light source device, projector, and discharge lamp driving method

Patent metadata

Field	Value
Publication number	US-9398275-B2
Application number	US-201514637147-A
Country	US
Kind code	B2
Filing date	Mar 3, 2015
Priority date	Mar 11, 2014
Publication date	Jul 19, 2016
Grant date	Jul 19, 2016

Abstract

A discharge lamp driving device includes: a discharge lamp driving unit that supplies a driving current for driving a discharge lamp to the discharge lamp; and a control unit that controls the discharge lamp driving unit. The control unit controls the discharge lamp driving unit such that the driving current having driving periods is supplied to the discharge lamp, the driving period including: a mixing period which alternately has an AC period in which an alternating current is supplied to the discharge lamp and a first DC period in which a direct current is supplied to the discharge lamp and a second DC period which is provided immediately after the mixing period and in which a direct current having a polarity which is opposite to that of the direct current in the first DC period is supplied to the discharge lamp.

First claim

What is claimed is:

1. A discharge lamp driving device comprising:
a discharge lamp driving unit that supplies a driving current for driving a discharge lamp to the discharge lamp; and
a control unit that controls the discharge lamp driving unit,
wherein the control unit controls the discharge lamp driving unit such that the driving current having driving periods is supplied to the discharge lamp, the driving period including:
a mixing period which alternately has an AC period in which an alternating current is supplied to the discharge lamp and a first DC period in which a direct current is supplied to the discharge lamp and
a second DC period which is provided immediately after the mixing period and in which a direct current having a polarity which is opposite to that of the direct current in the first DC period is supplied to the discharge lamp, and

the length of the first DC period is shorter than the length of the AC period, longer than the length of a half cycle of the alternating current in the AC period, shorter than the length of the second DC period, and equal to or greater than 0.5 ms and equal to or less than 7.0 ms.

2. The discharge lamp driving device according to claim 1 ,
wherein the driving current has a plurality of the driving periods,
the direct currents in the first DC periods of the adjacent driving periods have different polarities from each other, and
the direct currents in the second DC periods of the adjacent driving periods have different polarities from each other.

3. The discharge lamp driving device according to claim 1 , wherein the number of the first DC periods included in the mixing period is equal to or greater than 5 and equal to or less than 50.

4. The discharge lamp driving device according to claim 1 , wherein a frequency of the alternating current in the AC period is equal to or greater than 1 kHz.

5. The discharge lamp driving device according to claim 1 , wherein the length of the AC period is equal to or greater than 1 cycle and equal to or less than 20 cycles.

6. The discharge lamp driving device according to claim 1 , wherein the length of the first DC period is equal to or greater than 1.0 ms and equal to or less than 5.0 ms.

7. A projector comprising:
a discharge lamp that emits light,
the discharge lamp driving device according to claim 1 ;
a light modulation element that modulates light emitted from the discharge lamp according to a video signal; and
a projection optical system that projects the light modulated by the light modulation element.

8. A projector comprising:
a discharge lamp that emits light,
the discharge lamp driving device according to claim 2 ;
a light modulation element that modulates light emitted from the discharge lamp according to a video signal; and
a projection optical system that projects the light modulated by the light modulation element.

9. A projector comprising:
a discharge lamp that emits light,
the discharge lamp driving device according to claim 3 ;
a light modulation element that modulates light emitted from the discharge lamp according to a video signal; and
a projection optical system that projects the light modulated by the light modulation element.

10. A projector comprising:
a discharge lamp that emits light,
the discharge lamp driving device according to claim 4 ;
a light modulation element that modulates light emitted from the discharge lamp according to a video signal; and
a projection optical system that projects the light modulated by the light modulation element.

11. A projector comprising:
a discharge lamp that emits light,
the discharge lamp driving device according to claim 5 ;
a light modulation element that modulates light emitted from the discharge lamp according to a video signal; and
a projection optical system that projects the light modulated by the light modulation element.

12. A projector comprising:
a discharge lamp that emits light,
the discharge lamp driving device according to claim 6 ;
a light modulation element that modulates light emitted from the discharge lamp according to a video signal; and
a projection optical system that projects the light modulated by the light modulation element.

13. A method of driving a discharge lamp that is driven by supplying a driving current to the discharge lamp, the method comprising:
supplying the driving current having driving periods to the discharge lamp, the driving period including:
a mixing period which alternately has an AC period in which an alternating current is supplied to the discharge lamp and a first DC period in which a direct current is supplied to the discharge lamp and
a second DC period which is provided immediately after the mixing period and in which a direct current having a polarity which is opposite to that of the direct current in the first DC period is supplied to the discharge lamp,

wherein the length of the first DC period is shorter than the length of the AC period, longer than the length of a half cycle of the alternating current in the AC period, shorter than the length of the second DC period, and equal to or greater than 0.5 ms and equal to or less than 7.0 ms.

14. The method of driving a discharge lamp according to claim 13 ,
wherein the driving current has a plurality of the driving periods,
the direct currents in the first DC periods of the adjacent driving periods have different polarities from each other, and
the direct currents in the second DC periods of the adjacent driving periods have different polarities from each other.

Assignees

• Seiko Epson Corp

Inventors

• Suzuki Junichi
• Nakagomi Yoichi

Classifications

• H05B41/3928

  for high-pressure lamps, e.g. high-intensity discharge lamps, high-pressure mercury or sodium lamps · CPC title

• G03B21/202

  Incandescent light sources · CPC title

• H04N9/312 Primary

  Driving therefor (driving of electronic spatial light modulators in displays other than projection devices G09G3/34, G09G3/36; control of liquid crystal elements G02F1/133; control of micromechanical modulators G02B26/08) · CPC title

• H04N9/3105

  for displaying all colours simultaneously, e.g. by using two or more electronic spatial light modulators (simultaneous projection in colour photography G03B33/10; beam splitting or combining systems per se G02B27/10) · CPC title

• G03B21/005

  Projectors using an electronic spatial light modulator but not peculiar thereto · CPC title