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

Patent metadata

Field	Value
Publication number	US-9532439-B2
Application number	US-201414503853-A
Country	US
Kind code	B2
Filing date	Oct 1, 2014
Priority date	Oct 11, 2013
Publication date	Dec 27, 2016
Grant date	Dec 27, 2016

Abstract

A discharge lamp driving device includes: a discharge lamp driving unit which supplies drive power to a discharge lamp; and a control unit which controls the discharge lamp driving unit according to a waveform of the drive power. The waveform has n launching periods and a low-power mode lighting period. The n launching periods include a first launching period in which the drive power increases toward refresh power that is equal to or above drive power in a low-power mode and equal to or below rated power, and (n−1) launching periods in which the drive power is maintained at the refresh power. The control unit, in an x-th launching period, supplies the discharge lamp with a drive current having a drive frequency equal to or below a drive frequency of a drive current supplied to the discharge lamp in an (x−1)th launching period.

First claim

What is claimed is:

1. A discharge lamp driving device comprising:
a discharge lamp driving unit which supplies drive power to a discharge lamp; and
a control unit which controls the discharge lamp driving unit according to a waveform of the drive power;
wherein the waveform has n (n being a natural number equal to or above 2) launching periods and a low-power mode lighting period,
the n launching periods include:
a first launching period in which the drive power increases toward refresh power that is equal to or above drive power in a low-power mode and equal to or below rated power, and
(n−1) launching periods in which the drive power is maintained at the refresh power,

the control unit, in an x-th (x being a natural number equal to or above 2 and equal to or below n) launching period, supplies the discharge lamp with a drive current having a drive frequency equal to or below a drive frequency of a drive current supplied to the discharge lamp in an (x−1)th launching period, and
the control unit adjusts at least the drive frequency that is a part of the drive frequencies in the plural launching periods according to a degree of deterioration of the discharge lamp.

2. The discharge lamp driving device according to claim 1 , wherein the drive current in the n launching periods intermittently includes a second waveform pattern having a higher load on the discharge lamp than in a first waveform pattern that is a basic waveform pattern of the drive current supplied to the discharge lamp in each launching period.

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

4. The discharge lamp driving device according to claim 2 , wherein the drive current includes the second waveform pattern in the (n−1) launching periods in which the drive power is maintained at the refresh power.

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

6. The discharge lamp driving device according to claim 2 , wherein the control unit adjusts at least one of an insertion time of the second waveform pattern, an insertion interval of the second waveform pattern, a number of times of insertion of the second waveform pattern, and a configuration of the second waveform pattern, according to the degree of deterioration of the discharge lamp.

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

8. The discharge lamp driving device according to claim 2 , wherein the second waveform pattern includes a drive current pattern having a drive frequency equal to or below 500 Hz or a drive current pattern combining DC driving and AC driving.

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

10. The discharge lamp driving device according to claim 1 , wherein the control unit detects the degree of deterioration of the discharge lamp by referring to an inter-electrode voltage of the discharge lamp in the low-power mode.

11. The discharge lamp driving device according to claim 10 , wherein the control unit refers to the inter-electrode voltage at an arbitrary time point in the first launching period and estimates the inter-electrode voltage in the low-power mode on the basis of the result of the reference to the inter-electrode voltage.

12. The discharge lamp driving device according to claim 10 , wherein the control unit reads out the inter-electrode voltage referred to and stored at the time of previous lighting of the discharge lamp, at the time of next lighting of the discharge lamp, and estimates the inter-electrode voltage in the low-power mode on the basis of the result of the reading of the inter-electrode voltage.

13. The discharge lamp driving device according to claim 1 , wherein the drive frequency in the first launching period is equal to or above 500 Hz.

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

15. A discharge lamp driving method in which a discharge lamp is driven according to a waveform of drive power having n (n being a natural number equal to or above 2) launching periods and a low-power mode lighting period,
the n launching periods including a first launching period in which the drive power increases toward refresh power that is equal to or above drive power in a low-power mode and equal to or below rated power, and (n−1) launching periods in which the drive power is maintained at the refresh power,
the method comprising:
in an x-th (x being a natural number equal to or above 2 and equal to or below n) launching period, supplying the discharge lamp with a drive current having a drive frequency equal to or below a drive frequency of a drive current supplied to the discharge lamp in an (x−1)th launching period; and
adjusting at least the drive frequency that is a part of the drive frequencies in the plural launching periods according to a degree of deterioration of the discharge lamp.

Assignees

• Seiko Epson Corp

Inventors

• Nakagomi Yoichi
• Suzuki Junichi

Classifications

• H05B41/382

  during the transitional start-up phase · CPC title

• H05B41/16

  in which the lamp is fed by DC or by low-frequency AC, e.g. by 50 cycles/sec AC {, or with network frequencies} · CPC title

• H04N9/3197

  using light modulating optical valves · CPC title

• H04N9/312

  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

• H04N9/3167

  for polarizing the light beam (polarizing optical systems per se G02B27/28) · CPC title