Rear projection display device

• US 6,981,771 B1
• Filed: 06/30/2000
• Issued: 01/03/2006
• Est. Priority Date: 07/01/1999
• Status: Expired due to Term

• Current Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: Arai, Kazuhiro, Yoshii, Syoichi
• Primary Examiner(s): Perkey, W. B.
• Assistant Examiner(s): Cruz, Magda
• Application Number:
  US09/608,067
• Time in Patent Office: 2,013 Days
• Field of Search: 353/77, 353/29, 353/74, 353/71, 353/119, 353/31, 353 33- 34, 353/37, 353/20, 353/8, 349/5, 349 7- 9, 349/458, 359/460
• US Class Current: 353/74
• CPC Class Codes: G03B 21/10 Projectors with built-in or built-on screen
• CPC Class Codes: G03B 21/28 Reflectors in projection beam in illumination beam G03B21/2066

Abstract

A rear projection display device improves the brightness by improving the utilization efficiency of image light projected to a screen from slantly below. At least a green component of the image light is P-polarized to the screen (7). Therefore, reflection of light on the screen (7) is reduced.

Claims

1. A rear projection display device comprising a light source lamp, color splitting means for splitting light emitted from the light source lamp into a plurality of color components, a plurality of liquid crystal panels for optically modulating each color light split by the color splitting means, color synthesizing means for synthesizing each of the color light modulated by the liquid crystal panels, and projection means for projecting image light which is color-synthesized by the color synthesizing means on a screen from slantly above or slantly below,

wherein a polarization direction of at least one color component out of the image light irradiated on the screen is parallel to a vertical cross section of the screen, and the polarization direction of the at least one color component is manipulated to reduce reflection on the screen and to improve brightness,

wherein the polarization direction of at least the green component out of the image light irradiated on the screen is parallel to the vertical cross section of the screen,

wherein polarization direction adjusting means is provided for adjusting a polarization direction of at least the green component out of the image light synthesized by the color synthesizing means so that the polarization direction of at least the green component is parallel to the vertical cross section of the screen.

2. A rear projection display device comprising a light source lamp, color splitting means for splitting light emitted from the light source lamp into a plurality of color components, a plurality of liquid crystal panels for optically modulating each color light split by the color splitting means, color synthesizing means for synthesizing each of the color light modulated by the liquid crystal panels, and projection means for projecting image light which is color-synthesized by the color synthesizing means on a screen from slantly above or slantly below,

wherein a polarization direction of at least one color component out of the image light irradiated on the screen is parallel to a vertical cross section of the screen, and the polarization direction of the at least one color component is manipulated to reduce reflection on the screen and to improve brightness,

wherein the polarization direction of at least the green component out of the image light irradiated on the screen is parallel to the vertical cross section of the screen,

wherein polarization direction adjusting means is provided for adjusting a polarization direction of at least the green component out of the image light synthesized by the color synthesizing means so that the polarization direction of at least the green component is parallel to the vertical cross section of the screen,

wherein the polarization direction adjusting means comprises a retardation plate.

3. A rear projection display device comprising a light source lamp, color splitting means for splitting light emitted from the light source lamp into a plurality of color components, a plurality of liquid crystal panels for optically modulating each color light split by the color splitting means, color synthesizing means for synthesizing each of the color light modulated by the liquid crystal panels, and projection means for projecting image light which is color-synthesized by the color synthesizing means on a screen from slantly above or slantly below,

wherein a polarization direction of at least one color component out of the image light irradiated on the screen is parallel to a vertical cross section of the screen, and the polarization direction of the at least one color component is manipulated to reduce reflection on the screen and to improve brightness,

wherein polarization directions of all the color components of the image light irradiated on the screen are parallel to the vertical cross section of the screen,

wherein polarization direction adjusting means is provided for selectively adjusting a color component, of which a polarization direction is orthogonal with the vertical cross section of the screen, out of the image light synthesized by the color synthesizing means so that the polarization direction of the color component is parallel to the vertical cross section of the screen.

4. A rear projection display device comprising a light source lamp, color splitting means for splitting light emitted from the light source lamp into a plurality of color components, a plurality of liquid crystal panels for optically modulating each color light split by the color splitting means, color synthesizing means for synthesizing each of the color light modulated by the liquid crystal panels, and projection means for projecting image light which is color-synthesized by the color synthesizing means on a screen from slantly above or slantly below,

wherein a polarization direction of at least one color component out of the image light irradiated on the screen is parallel to a vertical cross section of the screen, and the polarization direction of the at least one color component is manipulated to reduce reflection on the screen and to improve brightness,

wherein polarization directions of all the color components of the image light irradiated on the screen are parallel to the vertical cross section of the screen,

wherein polarization direction adjusting means is provided for selectively adjusting a color component, of which a polarization direction is orthogonal with the vertical cross section of the screen, out of the image light synthesized by the color synthesizing means so that the polarization direction of the color component is parallel to the vertical cross section of the screen,

wherein the polarization direction adjusting means comprises a narrow band retardation plate.

5. A rear projection display device comprising a light source lamp, color splitting means for splitting light emitted from the light source lamp into a plurality of color components, a plurality of liquid crystal panels for optically modulating each color light split by the color splitting means, color synthesizing means for synthesizing each of the color light modulated by the liquid crystal panels, and projection means for projecting image light which is color-synthesized by the color synthesizing means on a screen from a slant side,

wherein a polarization direction of at least one color component out of the image light irradiated on the screen is parallel to a horizontal cross section of the screen, and the polarization direction of the at least one color component is manipulated to reduce reflection on the screen and to improve brightness,

wherein at least one of the color components is green,

wherein polarization direction adjusting means is provided for adjusting a polarization direction of at least the green component out of the image light irradiated on the screen so that the polarization direction of at least the green component is parallel to the horizontal cross section of the screen.

6. A rear projection display device comprising a light source lamp, color splitting means for splitting light emitted from the light source lamp into a plurality of color components, a plurality of liquid crystal panels for optically modulating each color light split by the color splitting means, color synthesizing means for synthesizing each of the color light modulated by the liquid crystal panels, and projection means for projecting image light which is color-synthesized by the color synthesizing means on a screen from a slant side,

wherein a polarization direction of at least one color component out of the image light irradiated on the screen is parallel to a horizontal cross section of the screen, and the polarization direction of the at least one color component is manipulated to reduce reflection on the screen and to improve brightness,

wherein at least one of the color components is green,

wherein polarization direction adjusting means is provided for adjusting a polarization direction of at least the green component out of the image light irradiated on the screen so that the polarization direction of at least the green component is parallel to the horizontal cross section of the screen,

wherein the polarization direction adjusting means comprises a retardation plate.

7. A rear projection display device comprising a light source lamp, color splitting means for splitting light emitted from the light source lamp into a plurality of color components, a plurality of liquid crystal panels for optically modulating each color light split by the color splitting means, color synthesizing means for synthesizing each of the color light modulated by the liquid crystal panels, and projection means for projecting image light which is color-synthesized by the color synthesizing means on a screen from a slant side,

wherein a polarization direction of at least one color component out of the image light irradiated on the screen is parallel to a horizontal cross section of the screen, and the polarization direction of the at least one color component is manipulated to reduce reflection on the screen and to improve brightness,

wherein polarization directions of all the color components of the image light irradiated on the screen are parallel to the horizontal cross section of the screen,

wherein polarization direction adjusting means is provided for selectively adjusting a color component, of which polarization direction is orthogonal with the horizontal cross section of the screen, out of the image light synthesized by the color synthesizing means so that the polarization direction of the color component is parallel to the horizontal cross section of the screen.

8. A rear projection display device comprising a light source lamp, color splitting means for splitting light emitted from the light source lamp into a plurality of color components, a plurality of liquid crystal panels for optically modulating each color light split by the color splitting means, color synthesizing means for synthesizing each of the color light modulated by the liquid crystal panels, and projection means for projecting image light which is color-synthesized by the color synthesizing means on a screen from a slant side,

wherein a polarization direction of at least one color component out of the image light irradiated on the screen is parallel to a horizontal cross section of the screen, and the polarization direction of the at least one color component is manipulated to reduce reflection on the screen and to improve brightness,

wherein polarization directions of all the color components of the image light irradiated on the screen are parallel to the horizontal cross section of the screen,

wherein polarization direction adjusting means is provided for selectively adjusting a color component, of which polarization direction is orthogonal with the horizontal cross section of the screen, out of the image light synthesized by the color synthesizing means so that the polarization direction of the color component is parallel to the horizontal cross section of the screen,

wherein the polarization direction adjusting means comprises a narrow band retardation plate.

9. A rear projection display device comprising a light source lamp, color splitting means for splitting light emitted from the light source lamp into a plurality of color components, a plurality of liquid crystal panels for optically modulating each color light split by the color splitting means, color synthesizing means for synthesizing each of the color light modulated by the liquid crystal panels, and projection means for slantly projecting image light which is color-synthesized by the color synthesizing means on a screen,

wherein a polarization direction of at least one color component out of the image light irradiated on the screen is parallel to a plane including the image light irradiated on the screen and a normal of the screen, and the polarization direction of the at least one color component is manipulated to reduce reflection on the screen and to improve brightness,

wherein at least one of the color components is green,

wherein polarization direction adjusting means is provided for adjusting a polarization direction of at least the green component out of the image light irradiated on the screen so that the polarization direction of at least the green component is parallel to the plane including the image light irradiated on the screen and the normal of the screen.

10. A rear projection display device comprising a light source lamp, color splitting means for splitting light emitted from the light source lamp into a plurality of color components, a plurality of liquid crystal panels for optically modulating each color light split by the color splitting means, color synthesizing means for synthesizing each of the color light modulated by the liquid crystal panels, and projection means for slantly projecting image light which is color-synthesized by the color synthesizing means on a screen,

wherein a polarization direction of at least one color component out of the image light irradiated on the screen is parallel to a plane including the image light irradiated on the screen and a normal of the screen, and the polarization direction of the at least one color component is manipulated to reduce reflection on the screen and to improve brightness,

wherein at least one of the color components is green,

wherein polarization direction adjusting means is provided for adjusting a polarization direction of at least the green component out of the image light irradiated on the screen so that the polarization direction of at least the green component is parallel to the plane including the image light irradiated on the screen and the normal of the screen,

wherein the polarization direction adjusting means comprises a retardation plate.

11. A rear projection display device comprising a light source lamp, color splitting means for splitting light emitted from the light source lamp into a plurality of color components, a plurality of liquid crystal panels for optically modulating each color light split by the color splitting means, color synthesizing means for synthesizing each of the color light modulated by the liquid crystal panels, and projection means for slantly projecting image light which is color-synthesized by the color synthesizing means on a screen,

wherein a polarization direction of at least one color component out of the image light irradiated on the screen is parallel to a plane including the image light irradiated on the screen and a normal of the screen, and the polarization direction of the at least one color component is manipulated to reduce reflection on the screen and to improve brightness,

wherein polarization directions of all the color components of the image light irradiated on the screen are parallel to the plane including the image light irradiated on the screen and the normal of the screen,

wherein polarization direction adjusting means is provided for selectively adjusting a color component, of which a polarization direction is orthogonal with the plane including the image light irradiated on the screen and the normal of the screen, out of the image light synthesized by the color synthesizing means so that the polarization direction of the color component is parallel to the plane.

12. A rear projection display device comprising a light source lamp, color splitting means for splitting light emitted from the light source lamp into a plurality of color components, a plurality of liquid crystal panels for optically modulating each color light split by the color splitting means, color synthesizing means for synthesizing each of the color light modulated by the liquid crystal panels, and projection means for slantly projecting image light which is color-synthesized by the color synthesizing means on a screen,

wherein a polarization direction of at least one color component out of the image light irradiated on the screen is parallel to a plane including the image light irradiated on the screen and a normal of the screen, and the polarization direction of the at least one color component is manipulated to reduce reflection on the screen and to improve brightness,

wherein polarization directions of all the color components of the image light irradiated on the screen are parallel to the plane including the image light irradiated on the screen and the normal of the screen,

wherein polarization direction adjusting means is provided for selectively adjusting a color component, of which a polarization direction is orthogonal with the plane including the image light irradiated on the screen and the normal of the screen, out of the image light synthesized by the color synthesizing means so that the polarization direction of the color component is parallel to the plane,

wherein the polarization direction adjusting means comprises a narrow band retardation plate.

13. A rear projection display device comprising:

a light source lamp,

color splitting means for splitting light emitted from the light source lamp into tree color components of red, green and blue,

a plurality of liquid crystal panels for optically modulating each color light split by the color splitting means,

color synthesizing means for synthesizing each of the color light modulated by the liquid crystal panels,

polarization direction adjusting means for selectively adjusting a color component which is an S-polarized component to a surface of a screen on which image light is irradiated, out of the image light synthesized by the color synthesizing means so that the S-polarized component becomes a P-polarized component to the surface of the screen on which the image light is irradiated, and

projection means for slantly projecting image light which is color-synthesized by the color synthesizing means on a screen,

wherein all color components out of the image light irradiated on the screen are P-polarized to the surface of the screen on which the image light is irradiated.

14. The rear projection display device according to claim 13, wherein

the polarization direction adjusting means comprises a narrow band retardation plate.

15. The rear projection display device according to claim 13, wherein

the relation i-min<

α

<

i-max is satisfied, where an angle of a maximum value i-max and a minimum value i-min is formed by a normal of a back surface of the screen and a principal ray of the image light irradiated on the back surface of the screen, and an angle α

is obtained when the reflectivity of light, which is P-polarized to the surface on which the image light is irradiated, to the back surface of the screen is minimum.

16. The rear projection display device according to claim 13, wherein

the relation j-min<

β

<

j-max is satisfied, where an angle of a maximum value j-max and a minimum value j-min is formed by a normal of a front surface of the screen and a principal ray of the image light irradiated on the front surface of the screen, and an angle β

is obtained when the reflectivity of light, which is P-polarized to the surface of the screen on which the image light is irradiated, to the front surface of the screen is minimum.