Image projection apparatus
First Claim
1. An image projection apparatus comprising a projection optical system for projecting an image displayed on a display surface onto a screen, the projection optical system including at least four curved reflecting surfaces,wherein the projection optical system does not form an intermediate real image of the display surface between the display surface and the screen, andwherein, assuming that a ray of light that travels from a center of the display surface through a center of an aperture stop to a center of the screen surface is called a screen center ray, the following conditions are fulfilled:
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0.5<
DL/HL<
3.5,
10<
θ
<
70,
Fnoy≦
3.5, and
Fnoz≦
3.4,whereDL represents an optical distance traveled by the screen center ray from a last surface of the projection optical system to the screen surface,HL represents a dimension of the screen surface in a direction parallel to a plane formed at the center of the screen surface by a normal to the screen surface and the screen center ray,θ
represents an angle of incidence at which the screen center ray is incident on the screen surface,Fnoy represents an f-number in a direction corresponding to the height direction of the display surface, andFnoz represents an f-number in a direction corresponding to the width direction of the display surface.
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Accused Products
Abstract
An oblique projection optical system for leading rays of light from a display surface on which an image is displayed to a projection surface in such a way that the ray of light from the center of the display surface is obliquely incident on the projection surface in order to project a magnified image of the image displayed on the display surface onto the projection surface includes a plurality of reflecting surfaces having a power. At least two of the reflecting surfaces have a free-form curved surface, and, of all the reflecting surfaces, the one closest to the projection surface has a negative power and at least one of the other has a positive power. Alternatively, in a rear projection optical system having a projection optical system for projecting an image displayed on a panel display surface onto a screen surface, the projection optical system includes at least four curved-surface reflecting mirrors.
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Citations
38 Claims
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1. An image projection apparatus comprising a projection optical system for projecting an image displayed on a display surface onto a screen, the projection optical system including at least four curved reflecting surfaces,
wherein the projection optical system does not form an intermediate real image of the display surface between the display surface and the screen, and wherein, assuming that a ray of light that travels from a center of the display surface through a center of an aperture stop to a center of the screen surface is called a screen center ray, the following conditions are fulfilled: -
0.5<
DL/HL<
3.5,
10<
θ
<
70,
Fnoy≦
3.5, and
Fnoz≦
3.4,where DL represents an optical distance traveled by the screen center ray from a last surface of the projection optical system to the screen surface, HL represents a dimension of the screen surface in a direction parallel to a plane formed at the center of the screen surface by a normal to the screen surface and the screen center ray, θ
represents an angle of incidence at which the screen center ray is incident on the screen surface,Fnoy represents an f-number in a direction corresponding to the height direction of the display surface, and Fnoz represents an f-number in a direction corresponding to the width direction of the display surface. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. An image projection apparatus comprising:
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a reflective display panel for displaying a two-dimensional image on a panel display surface thereof; and an oblique projection optical system for projecting the image on the panel display surface to a projection surface in such a way that a ray of light from a center of the panel display surface is obliquely incident on the projection surface, the oblique projection optical system being a substantially oblique telecentric optical system having an entrance pupil located substantially at infinity and inclined relative to an axis parallel to a height direction of the panel display surface, wherein the oblique projection optical system includes at least four curved reflecting surfaces. - View Dependent Claims (26, 27, 28, 29, 36, 37, 38)
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30. An image projection apparatus comprising:
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a reflective display panel for displaying a two-dimensional image on a panel display surface thereof; and an oblique proiection optical system for projecting the image on the panel display surface to a projection surface in such a way that a ray of light from a center of the panel display surface is obliquely incident on the projection surface, the oblique projection optical system being a substantially oblique telecentric optical system having an entrance pupil located substantially at infinity and inclined relative to an axis parallel to a height direction of the panel display surface, further comprising a screen located at the projection surface, the screen including an optical member, the optical member having a Fresnel portion, wherein the Fresnel portion fulfills the following condition;
[a pitch of the Fresnel portion]/[a size of a pixel of a projected image on the screen]<
0.5. - View Dependent Claims (31, 32, 33, 34, 35)
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Specification