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

Patent metadata

Field	Value
Publication number	US-9785041-B2
Application number	US-201615139022-A
Country	US
Kind code	B2
Filing date	Apr 26, 2016
Priority date	May 1, 2015
Publication date	Oct 10, 2017
Grant date	Oct 10, 2017

Abstract

A discharge lamp driving device includes a discharge lamp driving unit configured to supply a driving current to a discharge lamp including electrodes, a controller configured to control the discharge lamp driving unit, and a voltage detection unit configured to detect an inter-electrode voltage of the discharge lamp, in which the controller controls the discharge lamp driving unit so that the driving current includes a hybrid period in which a first period for supplying an AC current with a first frequency to the discharge lamp and a second period for supplying a DC current to the discharge lamp are alternately repeated, in which the first frequency includes a plurality of different frequencies, and in which the controller changes the first frequency on the basis of at least one of the detected inter-electrode voltage and driving power supplied to the discharge lamp.

First claim

What is claimed is:

1. A discharge lamp driving device comprising:
a discharge lamp driving unit configured to supply a driving current to a discharge lamp including electrodes;
a controller configured to control the discharge lamp driving unit; and
a voltage detection unit configured to detect an inter-electrode voltage of the discharge lamp,
wherein the controller controls the discharge lamp driving unit so that the driving current includes a hybrid period in which a first period for supplying an AC current with a first frequency to the discharge lamp and a second period for supplying a DC current to the discharge lamp are alternately repeated,
wherein the first frequency includes a plurality of different frequencies, and
wherein the controller changes the first frequency on the basis of at least one of the detected inter-electrode voltage and driving power supplied to the discharge lamp.

2. The discharge lamp driving device according to claim 1 ,
wherein the controller sets the first frequency on the basis of the detected inter-electrode voltage, and
wherein the first frequency is set to become higher as the inter-electrode voltage increases.

3. The discharge lamp driving device according to claim 1 ,
wherein the controller sets the first frequency on the basis of the driving power, and
wherein the first frequency is set to become higher as the driving power is reduced.

4. The discharge lamp driving device according to claim 1 ,
wherein the first period includes a plurality of AC periods in which frequencies of the AC current supplied to the discharge lamp are different from each other, and
wherein the frequency of the AC current in the AC period becomes lower as the AC period is provided temporally later in the first period.

5. The discharge lamp driving device according to claim 1 ,
wherein the controller changes a length of the second period on the basis of at least one of the detected inter-electrode voltage and the driving power.

6. The discharge lamp driving device according to claim 1 ,
wherein, in a case where the detected inter-electrode voltage is higher than a first predetermined value, or the driving power supplied to the discharge lamp is lower than a second predetermined value, the controller controls the discharge lamp driving unit so that a third period is provided instead of the second period,
wherein the third period alternately includes a first DC period in which a DC current is supplied to the discharge lamp, and a second DC period in which a DC current with a polarity opposite to a polarity of the DC current supplied to the discharge lamp in the first DC period is supplied to the discharge lamp,
wherein a length of the first DC period is longer than a length of the second DC period, and
wherein the length of the second DC period is less than 0.5 ms.

7. A discharge lamp driving device comprising:
a discharge lamp driving unit configured to supply a driving current to a discharge lamp including electrodes; and
a controller configured to control the discharge lamp driving unit,
wherein the controller controls the discharge lamp driving unit to provide
a hybrid period in which a first period for supplying an AC current with a first frequency to the discharge lamp and a second period for supplying a DC current to the discharge lamp are alternately repeated,
a fourth period in which an AC current with a second frequency lower than the first frequency is supplied to the discharge lamp, and
a fifth period alternately including a third DC period in which a DC current is supplied to the discharge lamp, and a fourth DC period in which a DC current with a polarity opposite to a polarity of the DC current supplied to the discharge lamp in the third DC period is supplied to the discharge lamp,

wherein a length of the third DC period is longer than a length of the fourth DC period,
wherein the length of the fourth DC period is less than 0.5 ms, and
wherein a total of lengths of the third DC periods in the fifth period is longer than a length of the second period, and is longer than a length of half a cycle of the AC current with the second frequency in the fourth period.

8. The discharge lamp driving device according to claim 7 ,
wherein the length of the third DC period is ten times or more the length of the fourth period.

9. The discharge lamp driving device according to claim 7 ,
wherein the total of the lengths of the third DC periods in the fifth period is equal to or larger than 10 ms and equal to or less than 1.0 s.

10. The discharge lamp driving device according to claim 7 ,
wherein a plurality of the hybrid periods are provided, and
wherein the fifth period is provided between the hybrid periods which are temporally adjacent to each other, and is provided immediately after the first period.

11. The discharge lamp driving device according to claim 7 ,
wherein a plurality of the hybrid periods are provided, and
wherein the fourth period is provided between the hybrid periods which are temporally adjacent to each other, and is provided immediately after the first period.

12. The discharge lamp driving device according to claim 7 ,
wherein the controller controls the discharge lamp driving unit so that one of the fourth period and the fifth period is provided at a first predetermined interval.

13. The discharge lamp driving device according to claim 12 ,
wherein the controller controls the discharge lamp driving unit so that the fourth period is provided at a second predetermined interval larger than the first predetermined interval.

14. The discharge lamp driving device according to claim 13 ,
wherein the controller controls the discharge lamp driving unit to provide, in the second predetermined interval,
the fifth period alternately including the third DC period in which a DC current with a first polarity is supplied to the discharge lamp, and the fourth DC period in which a DC current with a second polarity is supplied to the discharge lamp, and
the fifth period alternately including the third DC period in which a DC current with the second polarity is supplied to the discharge lamp, and the fourth DC period in which a DC current with the first polarity is supplied to the discharge lamp.

15. The discharge lamp driving device according to claim 7 ,
wherein the first frequency includes a plurality of different frequencies.

16. The discharge lamp driving device according to claim 15 ,
wherein the first period includes a plurality of AC periods in which frequencies of the AC current supplied to the discharge lamp are different from each other, and
wherein the frequency of the AC current in the AC period becomes lower as the AC period is provided temporally later in the first period.

17. The discharge lamp driving device according to claim 7 ,
wherein a polarity of the DC current supplied to the discharge lamp in the third DC period and a polarity of the DC current supplied to the discharge lamp in the fourth DC period are inverted whenever the fifth period is provided.

18. The discharge lamp driving device according to claim 7 ,
wherein a starting polarity of the fourth period is inverted whenever the fourth period is provided.

19. The discharge lamp driving device according to claim 7 ,
wherein a polarity of the DC current supplied to the discharge lamp in the second period of the hybrid period is inverted whenever the second period is provided.

20. The discharge lamp driving device according to claim 7 , further comprising:

Assignees

• Seiko Epson Corp

Inventors

• Sato Shun
• Suzuki Junichi
• Kito Satoshi

Classifications

• H05B41/2886

  comprising a controllable preconditioner, e.g. a booster · CPC title

• G03B21/2053 Primary

  Intensity control of illuminating light (controlled by video signal processing H04N5/74 or H04N9/31) · CPC title

• H05B41/38

  Controlling the intensity of light · CPC title

• H05B41/2887

  characterised by a controllable bridge in the final stage · CPC title

• G03B21/2026

  Gas discharge type light sources, e.g. arcs · CPC title