# US 8,783,876 B2 · Projector that controls discharge lamp in response to deterioration

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- Number: US 8,783,876 B2
- Document ID: US8783876B2
- Status: Granted
- Kind: B2
- Application number: 13/316,819
- Filed: 2011-12-12
- Published: 2012-06-28
- Granted: 2014-07-22
- Earliest claimed: 2010-12-24
- Assignees: Seiko Epson Corporation
- Applicants: Tetsuo Terashima; Shun Sato
- Inventors: Tetsuo Terashima; Shun Sato
- Web page: https://patentgrep.com/patent/US8783876B2

## CPC

- G03B 21/2053: {Intensity control of illuminating light (controlled by video signal processing H04N5/74 or H04N9/31)}
- G03B 35/16: by sequential viewing
- H04N 9/3155: {for controlling the light source (light source control per se H05B35/00 – H05B47/00; control of an illumination source for displays in general G09G3/3406)}
- H04N 13/341: using temporal multiplexing
- H04N 13/363: using image projection screens (volumetric display H04N13/388)
- H05B 41/2887: {characterised by a controllable bridge in the final stage}
- H05B 41/2928: {for protecting the lamp against abnormal operating conditions}
- H05B 45/375: using buck topology
- G03B: APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR (optical parts of such apparatus G02B; photosensitive materials or processes for photographic purposes G03C; apparatus for processing exposed photographic materials G03D)
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION
- H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL

## Abstract

A projector that outputs a first image and a second image alternately, includes a discharge lamp driving section that supplies, to a discharge lamp, a drive current that drives the discharge lamp; a state detecting section that detects a deteriorating state of the discharge lamp; and a control section that controls the discharge lamp driving section, wherein the control section controls the discharge lamp driving section so that the absolute value of the drive current becomes relatively small in the first period and relatively large in the second period and, in the second period, the control section controls the discharge lamp driving section so that the discharge lamp driving section supplies an alternating current to the discharge lamp as the drive current and controls the discharge lamp driving section so that at least part of the frequency of the drive current is decreased with the progress of the deteriorating state.

## Claims

### Claim 1

A projector that outputs a first image and a second image alternately while performing switching between the first image and the second image with given switching timing, comprising:
a discharge lamp;
a discharge lamp driving section that supplies, to the discharge lamp, a drive current that drives the discharge lamp;
a state detecting section that detects a deteriorating state of the discharge lamp; and
a control section that controls the discharge lamp driving section,
wherein
a period sandwiched between a time at which switching is performed and the next time at which switching is performed starts with a first period and ends with a second period,
the control section controls the discharge lamp driving section so that the absolute value of the drive current becomes relatively small in the first period and relatively large in the second period, and
in the second period,
the control section controls the discharge lamp driving section so that the discharge lamp driving section supplies an alternating current to the discharge lamp as the drive current, and
the control section controls the discharge lamp driving section so that at least part of the frequency of the drive current is decreased with the progress of the deteriorating state.

### Claim 2 (depends on 1)

The projector according to claim 1, wherein
in the first period,
the control section controls the discharge lamp driving section so that the discharge lamp driving section supplies an alternating current to the discharge lamp as the drive current, and
the control section controls the discharge lamp driving section so that at least part of the frequency of the drive current is increased with the progress of the deteriorating state.

### Claim 3 (depends on 1)

The projector according to claim 1, wherein
the control section controls the discharge lamp driving section so that the average value of drive power throughout the first period and the second period becomes constant.

### Claim 4 (depends on 1)

The projector according to claim 1, wherein
the control section controls the discharge lamp driving section so that the drive current undergoes polarity reversal within the first period and undergoes polarity reversal within the second period.

### Claim 5 (depends on 1)

The projector according to claim 1, wherein
the control section controls the discharge lamp driving section so that the average value of the drive power remains constant in the first period and in the second period as the frequency value is decreased.