Discharge lamp lighting apparatus and projector

Patent metadata

Field	Value
Publication number	US-9578726-B2
Application number	US-201213672149-A
Country	US
Kind code	B2
Filing date	Nov 8, 2012
Priority date	Nov 11, 2011
Publication date	Feb 21, 2017
Grant date	Feb 21, 2017

Abstract

A discharge lamp lighting apparatus for lighting a discharge lamp in which an electric discharge medium, which contains xenon, is enclosed in an electric discharge container, and a pair of cathode electrode and anode electrode for main discharge is arranged to face each other, comprises a starter for generating dielectric breakdown in the electric discharge container of a discharge lamp, and a power supply circuit for supplying discharge current to the discharge lamp, wherein the power supply circuit has an output current modulation circuit for modulating the magnitude of current passed through the discharge lamp in at least a lighting steady state, according to a modulation signal, and wherein the output current modulation circuit controls speed of change so as to be 2.6 A or less per millisecond in case the magnitude of the lamp current per square millimeter in a cross section of the cathode electrode decreases.

First claim

What is claimed is:

1. A discharge lamp lighting apparatus for lighting a discharge lamp in which an electric discharge medium, which contains xenon, is enclosed in an electric discharge container, and a cathode electrode and anode electrode for main discharge are arranged to face each other, the discharge lamp lighting apparatus comprising:
a starter that generates a high voltage at start-up time to produce dielectric breakdown in the electric discharge container of the discharge lamp, and
a power supply circuit that supplies discharge current to the discharge lamp,
wherein the power supply circuit comprises an output current modulation circuit that is controllable by a modulation signal to modulate a magnitude of the discharge current by superimposing a rectangle pulsed current onto the discharge current, the discharge current continuously passes through the discharge lamp in at least a lighting steady state,
wherein the output current modulation circuit is configured to control a speed at which a magnitude of the discharge current per square millimeter in a cross section of the cathode electrode decreases by an amount not greater than 3.0 A per millisecond.

2. The discharge lamp lighting apparatus according to claim 1 , wherein the output current modulation circuit limits the speed at which the magnitude of the discharge current per square millimeter in a cross section of the cathode electrode decreases to a speed at which undershoot of lamp voltage does not occur.

3. The discharge lamp lighting apparatus according to claim 1 , wherein the output current modulation circuit controls the speed at which the magnitude of the discharge current per square millimeter in a cross section of the cathode electrode increases so as to be 2.6 A per millisecond or less.

4. The discharge lamp lighting apparatus according to claim 1 , wherein the output current modulation circuit limits the speed at which the magnitude of the discharge current per square millimeter in a cross section of the cathode electrode increases to a speed at which overshoot of the lamp voltage does not occur.

5. The discharge lamp lighting apparatus according to claim 2 , wherein the output current modulation circuit controls the speed at which the magnitude of the discharge current per square millimeter in a cross section of the cathode electrode increases so as to be 2.6 A per millisecond or less.

6. The discharge lamp lighting apparatus according to claim 2 , wherein the output current modulation circuit limits the speed at which the magnitude of the discharge current per square millimeter in a cross section of the cathode electrode increases to a speed at which overshoot of the lamp voltage does not occur.

7. The discharge lamp lighting apparatus according to claim 3 , wherein the output current modulation circuit limits the speed at which the magnitude of the discharge current per square millimeter in a cross section of the cathode electrode increases to a speed at which overshoot of the lamp voltage does not occur.

8. A projector comprising the discharge lamp lighting apparatus of claim 1 , which starts and lights the discharge lamp, wherein light flux generated by the discharge lamp is changed into color sequential light flux by a dynamic colored filter, whereby an image is displayed by projection using the color sequential light flux.

9. A method of lighting a discharge lamp in which an electric discharge medium, which contains xenon, is enclosed in an electric discharge container, and a cathode electrode and anode electrode for main discharge are arranged to face each other, the method comprising:
supplying a discharge current to the discharge lamp,
applying a modulation signal to modulate a magnitude of the discharge current by superimposing a rectangle pulsed current onto the discharge current, the discharge current continuously passes through the discharge lamp in at least a lighting steady state, and
controlling a speed at which a magnitude of the discharge current per square millimeter in a cross section of the cathode electrode decreases by an amount not greater than 3.0 A per millisecond.

10. The method of claim 9 , further comprising limiting the speed at which the magnitude of the discharge current per square millimeter in a cross section of the cathode electrode decreases to a speed at which undershoot of lamp voltage does not occur.

11. The method of claim 9 , further comprising controlling the speed at which the magnitude of the discharge current per square millimeter in a cross section of the cathode electrode (E 1 ) increases so as to be 2.6 A per millisecond or less.

12. The method of claim 9 , further comprising limiting the speed at which the magnitude of the discharge current per square millimeter in a cross section of the cathode electrode increases to a speed at which overshoot of the lamp voltage does not occur.

13. A method of lighting a discharge lamp according to claim 1 , the method comprising:
supplying a discharge current to the discharge lamp,
modulating the magnitude of the discharge current passed through the discharge lamp in at least a lighting steady state, according to a modulation signal, and
controlling a speed at which the magnitude of the discharge current per square millimeter in a cross section of the cathode electrode decreases so as to be 3.0 A or less per millisecond.

14. The method of claim 13 , further comprising limiting the speed at which the magnitude of the discharge current per square millimeter in a cross section of the cathode electrode decreases to a speed at which undershoot of lamp voltage does not occur.

15. The method of claim 13 , further comprising controlling the speed at which the magnitude of the discharge current per square millimeter in a cross section of the cathode electrode increases so as to be 2.6 A per millisecond or less.

16. The method of claim 13 , further comprising limiting the speed at which the magnitude of the discharge current per square millimeter in a cross section of the cathode electrode increases to a speed at which overshoot of the lamp voltage does not occur.

17. The method of claim 13 , wherein the magnitude of the discharge current per square millimeter in a cross section of the cathode decreases by an amount not greater than 1.6 A per millisecond.

18. The discharge lamp lighting apparatus according to claim 1 , wherein the magnitude of the discharge current per square millimeter in a cross section of the cathode electrode decreases by an amount not greater than 1.6 A per millisecond.

19. The method of claim 9 , wherein the magnitude of the discharge current per square millimeter in a cross section of the cathode decreases by an amount not greater than 1.6 A per millisecond.

Assignees

• Ushio Electric Inc

Inventors

• Okamoto Masashi

Classifications

• G03B21/2053

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

• G03B21/14

  Details · CPC title

• H05B41/2928 Primary

  for protecting the lamp against abnormal operating conditions · CPC title

• H05B41/3928

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

• Y02B20/202

  Cross-Sectional Technologies · mapped topic