Light source drive device, display apparatus, and light source drive method

Patent metadata

Field	Value
Publication number	US-9538627-B2
Application number	US-201414157925-A
Country	US
Kind code	B2
Filing date	Jan 17, 2014
Priority date	Feb 7, 2013
Publication date	Jan 3, 2017
Grant date	Jan 3, 2017

Abstract

A light source drive device includes a supply unit that supplies a high-frequency first drive signal and a second drive signal whose frequency is lower than a frequency of the first drive signal to a discharge lamp which has a pair of electrodes, and a control unit that controls the supply unit so that the first drive signal and the second drive signal of fixed durations are alternately supplied and that controls the supply unit so that the first drive signal is supplied in a case where a voltage between the pair of electrodes is below a threshold.

First claim

What is claimed is:

1. A light source drive device comprising:
a supply unit that supplies a first drive signal which has a first frequency and a second drive signal which has a second frequency lower than the first frequency of the first drive signal to a discharge lamp which has a pair of electrodes; and
a control unit that controls the supply unit so that the first drive signal and the second drive signal are alternately supplied to the discharge lamp, wherein
when a voltage between the pair of electrodes is below a threshold, the control unit is configured to switch from the second drive signal to the first drive signal; and
when the voltage is not below the threshold, and a time during which the second drive signal is supplied to the discharge lamp exceeds a predetermined period, the control unit is configured to switch from the second drive signal to the first drive signal.

2. The light source drive device according to claim 1 ,
wherein the control unit controls the supply unit so that the first drive signal and the second drive signal are alternately supplied to the discharge lamp, since the voltage between the pair of electrodes is below the threshold.

3. A display apparatus comprising:
a discharge lamp that includes a pair of electrodes;
the light source drive device according to claim 2 ; and
an optical modulator that modulates light which is output from the discharge lamp according to image data.

4. The light source drive device according to claim 1 ,
wherein the control unit controls the supply unit so that the predetermined period is lengthened as the voltage between the air of electrodes increases.

5. A display apparatus comprising:
a discharge lamp that includes a pair of electrodes;
the light source drive device according to claim 4 ; and
an optical modulator that modulates light which is output from the discharge lamp according to image data.

6. The light source drive device according to claim 1 ,
wherein the threshold is lower than a voltage between the pair of electrodes at a discharge initiation time of the discharge lamp and is equal to or higher than a voltage which is 10 V lower than the voltage between the pair of electrodes at the discharge initiation time of the discharge lamp.

7. The light source drive device according to claim 6 ,
wherein the threshold is lower than a voltage which is 3 V lower than the voltage between the pair of electrodes at the discharge initiation time of the discharge lamp and is equal to or higher than a voltage which is 7 V lower than the voltage between the pair of electrodes at the discharge initiation time of the discharge lamp.

8. A display apparatus comprising:
a discharge lamp that includes a pair of electrodes;
the light source drive device according to claim 7 ; and
an optical modulator that modulates light which is output from the discharge lamp according to image data.

9. A display apparatus comprising:
a discharge lamp that includes a pair of electrodes;
the light source drive device according to claim 6 , and
an optical modulator that modulates light which is output from the discharge lamp according to image data.

10. The light source drive device according to claim 1 ,
wherein the first frequency of the first drive signal is at least 1 kHz.

11. A display apparatus comprising:
a discharge lamp that includes a pair of electrodes;
the light source drive device according to claim 10 ; and
an optical modulator that modulates light which is output from the discharge lamp according to image data.

12. The light source drive device according to claim 1 ,
wherein the second drive signal has a plurality of frequency periods.

13. A display apparatus comprising:
a discharge lamp that includes a pair of electrodes;
the light source drive device according to claim 12 ; and
an optical modulator that modulates light which is output from the discharge lamp according to image data.

14. A display apparatus comprising:
a discharge lamp that includes a pair of electrodes;
the light source drive device according to claim 1 ; and
an optical modulator that modulates light which is output from the discharge lamp according to image data.

15. A light source drive method comprising:
alternately supplying a first drive signal which has a first frequency and a second drive signal is which has a second frequency lower than the first frequency of the first drive signal to a discharge lamp which has a pair of electrodes;
when a voltage between the pair of electrodes is below a threshold, switching from the second drive signal to the first drive signal; and
when the voltage is not below the threshold, and a time during which the second drive signal is supplied to the discharge lamp exceeds a predetermined period, switching from the second drive signal to the first drive signal.

Assignees

• Seiko Epson Corp

Inventors

• Suzuki Junichi

Classifications

• G03B21/2053

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

• G03B21/2026

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

• H05B41/2887 Primary

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

• H05B41/36

  Controlling · CPC title

• H05B41/2883

  the controlled element being a DC/AC converter in the final stage, e.g. by harmonic mode starting · CPC title