Projector

Patent metadata

Field	Value
Publication number	US-9250507-B2
Application number	US-201313955114-A
Country	US
Kind code	B2
Filing date	Jul 31, 2013
Priority date	Aug 3, 2012
Publication date	Feb 2, 2016
Grant date	Feb 2, 2016

Abstract

Two light modulators, a first light modulator and a second light modulator, suffice for four light sources, a first light source, a second light source, a third light source, and a fourth light source, whereby the cost can be lowered as compared with a configuration in which three light modulators are required. As a result, cost reduction is achieved. Further, since two light modulators suffice, the size of the projector can be reduced as compared with the configuration in which three light modulators are required.

First claim

What is claimed is:

1. A projector comprising:
a first light source that emits first light;
a second light source that emits second light having a wavelength shorter than the wavelength of the first light;
a first light modulator that modulates the first light and the second light and outputs the modulated light fluxes as first polarized light;
a third light source that emits third light having a wavelength shorter than the wavelength of the first light;
a fourth light source that emits fourth light having a wavelength shorter than the wavelength of the third light;
a second light modulator that modulates the third light and the fourth light and outputs the modulated light fluxes as second polarized light;
a combiner that combines the first light, the second light, the third light, and the fourth light by directing the first light and the second light having exited out of the first light modulator in a predetermined direction based on one of transmission and reflection and directing the third light and the fourth light having exited out of the second light modulator in the predetermined direction based on the other one of transmission and reflection different from the one of transmission and reflection; and
a controller that drives the first light source and the third light source to emit the first light and the third light simultaneously in a first period, drives the second light source and the fourth light source to emit the second light and the fourth light simultaneously in a second period following the first period, controls the first light modulator to perform modulation corresponding to the first light in the first period and modulation corresponding to the second light in the second period, and controls the second light modulator to perform modulation corresponding to the third light in the first period and modulation corresponding to the fourth light in the second period.

2. The projector according to claim 1 ,
wherein the first light is red light,
the second light and the third light are green light, and
the fourth light is blue light.

3. The projector according to claim 1 ,
wherein each of the first light source, the second light source, the third light source, and the fourth light source is a light emitting diode, and
the controller drives the first light source, the second light source, the third light source, and the fourth light source to emit light by supplying each of the first light source, the second light source, the third light source, and the fourth light source with a pulse voltage in the first period or the second period.

4. The projector according to claim 1 ,
wherein the first light modulator and the second light modulator modulate the first light, the second light, the third light, and the fourth light in such a way that an image formed by each of the first light, the second light, the third light, and the fourth light has a plurality of pixels arranged in a matrix, and
the first light modulator and the second light modulator are so disposed that the images formed by the first light and the second light modulated by the first light modulator and the images formed by the third light and the fourth light modulated by the second light modulator are combined with each other with the plurality of pixels contained in the images formed by the first light and the second light shifted from the plurality of pixels contained in the images formed by the third light and the fourth light in row and column directions by one-half the pitch between the pixels.

5. The projector according to claim 1 ,
wherein each of the first light modulator and the second light modulator is a liquid crystal device.

6. The projector according to claim 1 ,
wherein one of the first polarized light and the second polarized light is P-polarized light and the other is S-polarized light.

Assignees

• Seiko Epson Corp

Inventors

• Narimatsu Shuji
• Yajima Akitaka

Classifications

• G03B21/2033

  LED or laser light sources · CPC title

• G09G2340/0457

  Improvement of perceived resolution by subpixel rendering · CPC title

• G09G3/001

  using specific devices not provided for in groups G09G3/02 - G09G3/36, e.g. using an intermediate record carrier such as a film slide; Projection systems; Display of non-alphanumerical information, solely or in combination with alphanumerical information, e.g. digital display on projected diapositive as background (slide projectors per se G03B23/00 = 42 HP) · CPC title

• G02F1/1313

  specially adapted for a particular application · CPC title

• G03B33/12

  using beam-splitting or beam-combining systems, e.g. dichroic mirrors · CPC title