Projection Display Apparatus

• US 20070285621A1
• Filed: 04/25/2007
• Published: 12/13/2007
• Est. Priority Date: 05/16/2006
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Kimura, Nobuyuki
• Granted Patent: US 7,807,957 B2
• Time in Patent Office: Days
• US Class Current: 353/20
• CPC Class Codes: H04N 5/7416 involving the use of a spatial light modulator, e.g. a light valve, controlled by a video signal
• CPC Class Codes: H04N 9/3105 for displaying all colours simultaneously, e.g. by using two or more electronic spatial light modulators simultaneous projection in colour photography G03B33/10; beam splitting or combining systems per se G02B27/10
• CPC Class Codes: H04N 9/3152 for shaping the light beam beam shaping per se G02B27/09

Abstract

A projection display apparatus in which the longitudinal direction of an arc type lamp is parallel with the longitudinal direction of an aperture of a polarization exchange element.

Claims

1. A projection display apparatus comprising:

an arc type lamp for emitting a light beam having an illumination intensity distribution,

reflectors for reflecting the light beam from the arc type lamp,

an array lens group composed of a first and a second array lens, for equalizing the illumination intensity distribution of the light beam from the reflectors,

a polarization exchange element comprising plurality of polarization exchange portions each comprising light shield parts for blocking light beams from the array lens group, aperture parts for allowing the light beams from the array lens group to pass therethrough, a polarized beam splitter film for splitting the light beams from the aperture parts into two kinds of light beams having different polarized directions, a reflection film for reflecting the light beam reflected by the polarized beam splitter film, and a half wave phase difference plate for changing polarized directions of light beams transmitted through the beam splitter film, for unifying the polarized directions of the light beams,

an image display element for modulating the light beams from the polarization exchange element, and

a projection lens for projecting the light beams from the image display elements,

wherein the longitudinal direction of the arc type lamp is the same as the longitudinal direction of the apertures.

2. A projection display apparatus as set forth in claim 1, comprising the reflectors which are composed of a first reflector located in front of the lamp and having a revolution paraboloid shape and a second reflector arranged in rear of the lamp and having a spherical shape, for reflecting the light beam from the lamp, and

a parallelizing lens for parallelizing light beams emitted from the lamp other than those directed to the first and second reflector, and light beams reflected by the second reflector.

3. A projection display apparatus as set forth in claim 2, wherein the first reflector on the side near the lamp has a diameter which is equal to that of the parallelizing lens.

4. A projection display apparatus as set forth in claim 3, wherein the following relationship is satisfied:

L=(φ

/2)÷

tan(π

−

θ

)

where L is a distance from the center of the lamp to the parallelizing lens, θ

is an angle of a light beam which is reflected by the first reflector in an outermost effective range, from the optical axis of a light beam emitted from the lamp, and φ

is a diameter of the parallelizing lens.

5. A projection display apparatus as set forth in claim 4, wherein the following relationship is satisfied:

R=(N−

1)×

L

where R is a radius of curvature of the parallelizing lens, N is a refractive index and L is a distance from the center of the lamp to the parallelizing lens.

6. A projection display apparatus as set forth in claim 2, wherein the first reflector and the second reflector are integrally incorporated with each other.

7. A projection display apparatus, comprising:

an arc type lamp for emitting a light beam having an illumination intensity distribution,

a first reflector having a revolution paraboloid shape, for reflecting the light beam from the lamp,

a second reflector having a spherical shape, for reflecting the light beam from the lamp,

a parallelizing lens for parallelizing alight beams, other than those emitted to the first and the second reflector, and a light beam reflected by the second reflector,

an array lens group composed of a first and a second reflector, for equalizing the illumination intensity distributions of the light beams from the first reflector and the parallelizing lens,

a polarization exchange element comprising a plurality of polarization exchange portions each comprising light shield parts for blocking light beams from the array lens group, aperture parts for allowing the light beams from the array lens group to pass therethrough, a polarized beam splitter film for splitting the light beams from the aperture parts into two kinds of light beams having different polarized directions, a reflection film for reflecting the light beams reflected by the polarized beam splitter film, and a half wave phase difference plate for changing polarized directions of light beams transmitted through the beam splitter film, for unifying the polarized directions of the light beams,

an image display element for modulating the light beams from the polarization exchange element, and

a projection lens for projecting the light beams from the image display elements,

wherein the longitudinal direction of the arc type lamp is the same as the longitudinal direction of the apertures.

8. A projection type display apparatus as set forth in claim 7, wherein the first reflector on the side near the lamp has a diameter which is equal to that of the parallelizing lamp.

9. A projection display apparatus as set forth in claim 8, wherein the following relationship is satisfied:

L=(φ

/2)÷

tan(π

−

θ

)

where L is a distance from the center of the lamp to the parallelizing lens, θ

is an angle of a light beam which is reflected by the first reflector in an outermost effective range, from the optical axis of a light beam emitted from the lamp, and φ

is a diameter of the parallelizing lens.

10. A projection display apparatus as set forth in claim 9, wherein the following relationship is satisfied:

R=(N−

1)×

L

where R is a radius of curvature of the parallelizing lens, N is a refractive index and L is a distance from the center of the lamp to the parallelizing lens.

11. A projection display apparatus as set forth in claim 7, wherein the first reflector and the second reflector are integrally incorporated with each other.

12. A projection display apparatus, comprising:

an arc type lamp for emitting a light beam having an illumination intensity distribution,

a first reflector having a revolution paraboloid shape, for reflecting the light beam from the lamp,

a second reflector having a spherical shape, for reflecting the light beam from the lamp,

a parallelizing lens for parallelizing light beams other those emitted toward the first and second reflector, and a light beam reflected by the second reflector,

an array lens group composed of a first and a second reflector, for equalizing the illumination intensity distributions of the light beams from the first reflector and the parallelizing lens,

a polarization exchange element comprising a plurality of polarization exchange elements, each comprising light shield parts for blocking light beams from the array lens group, aperture parts for allowing the light beams from the array lens group to pass therethrough, a polarized beam splitter film for splitting the light beams from the apertures into two kinds of light beams having different polarized directions, a reflection film for reflecting the light beams reflected by the polarized beam splitter film, and a half wave phase difference plate for changing polarized directions of light beams transmitted through the beam splitter film, for unifying the polarized directions of the light beams,

a color separating portion for separating the light beams from the polarization exchange element into light beams having a plurality of colors,

a plurality of image display elements arranged for the plurality of colors,

an optical synthesizing prism for synthesizing the light beams from the plurality of image display elements, and

a projection lens for projecting the light beams from the plurality of image display elements,

wherein the longitudinal direction of the arc type lamp is the same as the longitudinal direction of the apertures.

13. A projection type display apparatus as set forth in claim 12, wherein the first reflector on the side near the lamp has a diameter which is equal to that of the parallelizing lamp.

14. A projection display apparatus as set forth in claim 13, wherein the following relationship is satisfied:

L=(φ

/2)÷

tan(π

−

θ

)

where L is a distance from the center of the lamp to the parallelizing lens, θ

is an angle of a light beam which is reflected by the first reflector in an outermost effective range, from the optical axis of a light beam emitted from the lamp, and φ

is a diameter of the parallelizing lens.

15. A projection display apparatus as set forth in claim 14, wherein the following relationship is satisfied:

R=(N−

1)×

L

where R is a radius of curvature of the parallelizing lens, N is a refractive index and L is a distance from the center of the lamp to the parallelizing lens.

16. A projection display apparatus as set forth in claim 12, wherein the first reflector and the second reflector are integrally incorporated with each other.