Projector

• US 8,823,885 B2
• Filed: 03/04/2011
• Issued: 09/02/2014
• Est. Priority Date: 03/23/2010
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Endo, Takashi, Masuda, Tomoharu
• Primary Examiner(s): KIM, RICHARD H
• Application Number:
  US13/040,746
• Publication Number:
  US 20110234928A1
• Time in Patent Office: 1,278 Days
• Field of Search: None
• US Class Current: 349/8
• CPC Class Codes: G03B 21/006 using LCD's
• CPC Class Codes: G03B 21/14 Details
• CPC Class Codes: G03B 21/2053 Intensity control of illuminating light controlled by video signal processing H04N5/74 or H04N9/31
• CPC Class Codes: G03B 21/206 Control of light source other than position or intensity
• CPC Class Codes: G03B 21/2073 Polarisers in the lamp house peculiar to electronic spatial light modulators H04N9/3197
• CPC Class Codes: G03B 33/12 using beam-splitting or beam-combining systems, e.g. dichroic mirrors
• CPC Class Codes: H04N 9/3167 for polarizing the light beam polarizing optical systems per se G02B27/28

Abstract

A projector includes: an illuminator that outputs illumination light; a light modulator including a liquid crystal panel and a structural birefringent polarization separation element having a polarization separation surface inclined away from a central axis of the illumination light, the light modulator modulating the illumination light from the illuminator; and a projection system that projects the light modulated by the light modulator, wherein the illumination light outputted from the illuminator has an angular distribution in a first direction, which is perpendicular to the central axis of the illumination light, smaller than the angular distribution in a second direction, which is perpendicular to the first direction and the central axis of the illumination light, and the polarization separation surface of the structural birefringent polarization separation element has a structure that is not periodic along the first direction but is periodic along the second direction.

Claims

1. A projector comprising:

an illuminator that outputs light having a central axis; and

a light modulator including a liquid crystal panel and a structural birefringent polarization separation element having a polarization separation surface inclined away from the central axis of the light, the light modulator modulating the light from the illuminator,

the light outputted from the illuminator having an angular distribution in a first direction that is perpendicular to the central axis of the light and an angular distribution in a second direction that is perpendicular to the first direction and to the central axis of the light, the angular distribution in the first direction being smaller than the angular distribution in the second direction, and

the polarization separation surface of the structural birefringent polarization separation element having a structure that is not periodic along the first direction but is periodic along the second direction,

wherein the illuminator includes a light level adjuster having a movable light blocker that adjusts the angular distribution of the light and

wherein the light blocker has an opening with a width that increases in the first direction as the position in the opening changes from one side to an another side of the light blocker along the second direction, and the opening is asymmetrical in the second direction.

2. The projector according to claim 1, further comprising:

a projection system that projects the light modulated by the light modulator;

a plurality of light modulators in addition to the light modulator;

a color separation/light guiding section that separates the light outputted from the illuminator into red light, green light and blue light, guides the green light to the light modulator, and guides the red light and the blue light to the plurality of other light modulators; and

a light combining section that combines the green light modulated by the light modulator with the red light and the blue light modulated by the plurality of other light modulators and causes the combined light to enter the projection system.

3. The projector according to claim 1, further comprising:

a projection system that projects the light modulated by the light modulator.

4. The projector according to claim 1, wherein the polarization separation surface is a striped shaped grid.

5. The projector according to claim 1, wherein the illuminator includes the light level adjuster having a pair of light blockers, and the light level adjuster opening changes by moving the light blockers either away from or toward each other in the first direction.

6. The projector according to claim 5, wherein under the condition that the light level adjuster opening width gradually decreases, the angular distribution in the first direction gradually decreases, which increases a difference in angular distribution between the first and second directions.

7. A projector comprising:

an illuminator that outputs light having a central axis;

a light modulator including a liquid crystal panel and a structural birefringent polarization separation element having a polarization separation surface inclined away from the central axis of the light, the light modulator modulating the light from the illuminator; and

a projection system that projects the light modulated by the light modulator as image light,

the polarization separation surface of the structural birefringent polarization separation element having a structure that is not periodic along a first direction, but is periodic along a second direction, the first direction being perpendicular to the central axis of the light, the second direction being perpendicular to the central axis of the light and the first direction,

wherein the illuminator includes a light level adjuster having a movable light blocker that adjusts the angular distribution of the light, the light outputted from the illuminator having an angular distribution in a first direction that is perpendicular to the central axis of the light and an angular distribution in a second direction that is perpendicular to the first direction and to the central axis of the light, the angular distribution in the first direction being smaller than the angular distribution in the second direction, and

wherein the light blocker has an opening with a width that increases in the first direction as the position in the opening changes from one side to an other side of the light blocker along the second direction, and the opening is asymmetrical in the second direction.