Abstract: A projection type image display apparatus in which shortening of the projection distance (widening of the angle of view) and miniaturization of the projection optic system are realized is provided. It comprises, in a traveling direction of the light, an image display element, a lens group including a plurality of lenses, a first lens, a second lens, and a mirror to reflect light emitted from the second lens to be projected obliquely on a screen in this order. The refractive power of the first lens is positive and the refractive power of the second lens is negative. The first and the second lenses are moved in an interlocked relationship with each other along an optical axis of the lens group and a movement amount of the first lens is made larger than a movement amount of the second lens.

Abstract: There is provided a projection apparatus using an oblique projection optical system, which generates little reflection loss by providing a linear Fresnel lens at an incident surface in the case where the apparatus is used as a linear system, wherein said linear Fresnel lens makes total reflection of image light, and is capable of obtaining total surface property with good brightness in a region with small incident angle onto a screen, by using a total reflection Fresnel lens and a refraction Fresnel lens in combination. In addition, total surface property with further good brightness can be obtained by using a plurality of projection image display apparatuses in the same projection apparatus.

Abstract: An object of the invention is to reduce the size and weight of a video projector by shortening the length of the arm of a mirror rotator and reducing the size of a mirror. A video projector comprises a plurality of projection lenses through which image light rays from a liquid crystal panel are extracted in a magnified manner; a reflective mirror for reflecting the extracted image light rays onto a screen; and a mirror rotator for rotating the reflective mirror so that the extracted image light rays can be reflected in particular directions. Among the projection lenses, some of the projection lenses located farther away from the liquid crystal penal are partially cut such that areas through which the image light rays do not pass are cut off to create a lens cut-off space. The mirror rotator is placed in the lens cut-off space.

Abstract: In a projection type display apparatus for enabling to display an image, by projecting an image on an image display element(s), enlargedly, upon a nearly horizontal surface, such as, a table, a reflection mirror for reflecting a light from a light source is so disposed that an optical axis of the light source is nearly perpendicular to an optical axis of a lens group having a plural number of lens elements, which are disposed symmetric with respect to the optical axis.

Abstract: A projection type display apparatus including an oblique projection optical system having a plurality of lenses is disclosed. A lens nearest to a projection screen has a vertical effective image area through which a light flux passes. The lens is arranged at a position not including an optical axis shared by the largest number of lenses among the plurality of lenses. A flat mirror for returning the optical path is arranged between the particular lens and the projection screen at a predetermined angle to the optical axis. An enlarged image obtained by the light flux returned by the flat mirror is formed toward a display screen.

Abstract: In a projection type display apparatus for enabling to display an image, by projecting an image on an image display element(s), enlargedly, upon a nearly horizontal surface, such as, a table, a reflection mirror for reflecting a light from a light source is so disposed that an optical axis of the light source is nearly perpendicular to an optical axis of a lens group having a plural number of lens elements, which are disposed symmetric with respect to the optical axis.

Abstract: An image displaying apparatus, comprising: a first light modulator unit, which is configured to modulate a light incident thereon, responding to a first video signal, thereby to form a first image; one or a plural number of second light modulator units, which is/are configured to modulate a light from a light source, responding to a second video signal; and an enlarged image forming unit, being disposed on a light incidence side of the first light modulator unit, upon which a light modulated within the second light modulator unit is projected, enlargedly, thereby to form a second image thereon, wherein upon the first light modulator unit is incident the light of the second image formed on the enlarged image forming unit, and the first image is formed through modulation of the light of the second image responding to the first video signal.

Abstract: A projection type display apparatus including an oblique projection optical system having a plurality of lenses is disclosed. A lens nearest to a projection screen has a vertical effective image area through which a light flux passes. The lens is arranged at a position not including an optical axis shared by the largest number of lenses among the plurality of lenses. A flat mirror for returning the optical path is arranged between the particular lens and the projection screen at a predetermined angle to the optical axis. An enlarged image obtained by the light flux returned by the flat mirror is formed toward a display screen.

Abstract: A projection type image display apparatus includes a first lens group including a plural number of lenses being disposed in a direction of propagation light with respect to an image display element, a second lens group including a plural number of lenses being disposed in a direction of propagation light with respect to said first lens group and a reflection mirror, which is configured to reflect light emitted from at least one of said first and second lens groups, so as to project the light obliquely upon a screen. A ratio (Lo/Lp) of a diagonal size (Lo) of said screen and a distance (Lp) from a center of said reflection mirror to said screen is at least 2, and the second lens group includes a refractive lens having a negative power and a rotationally symmetric surface configuration.

Abstract: A projection display system includes a projection display unit and a member in a form of one of a windable screen, a white board and a notice board. The projection display unit projects an image light onto a projection plane of the member to display an image thereon. The projection display unit includes a light source, an image display element, a lighting optical system irradiating a beam of light from the light source on the image display element, and a projection optical system projecting the image light from the image display element toward the member. The projection optical system includes, in order toward the member from the image display element, a front lens group, and a reflecting mirror shaped to be axial-asymmetrical with respect to the optical axis.

Abstract: In a projection type display apparatus for enabling to display an image, by projecting an image on an image display element(s), enlargedly, upon a nearly horizontal surface, such as, a table, a reflection mirror for reflecting a light from a light source is so disposed that an optical axis of the light source is nearly perpendicular to an optical axis of a lens group having a plural number of lens elements, which are disposed symmetric with respect to the optical axis.

Abstract: A projection type image display device using, in a projection optical system thereof, a flat mirror, which is easy to design and manufacture, as a projection mirror is provided. The projection optical system is a diagonal projection optical system and includes plural lenses. Among the plural lenses, the one disposed closest to the flat mirror has an effective area, along the vertical direction of an image, through which a light beam passes and which is off an optical axis of the other plurality of lenses, shared by the most lenses so as not to allow light reflected from the projection mirror to return to the projector body. A polarization converter using, for example, a quarter wavelength plate is provided at an output surface of a crossed prism to decrease reflectance differences between differently colored light and to thereby prevent the occurrence of color unevenness.

Abstract: A projection display system comprising a projection display unit including a light source, an image display element, a lighting optical system irradiating a beam of light on the image display element, and a projection optical system projecting an image light from the image display element toward a screen. The projection optical system including a lens group composed of a plurality of lens elements arranged in order toward the screen from the image display element and symmetrically with respect to an optical axis, and a reflecting mirror shaped to be axial-asymmetrical with respect to the optical axis. The projection display system further comprises a screen 5. The projection display unit projects the image light onto a projection plane of the screen to display an image.

Abstract: A projection type image display apparatus includes a first lens group including a plural number of lenses being disposed in a direction of propagation light with respect to an image display element, a second lens group including a plural number of lenses being disposed in a direction of propagation light with respect to said first lens group and a reflection mirror, which is configured to reflect light emitted from at least one of said first and second lens groups, so as to project the light obliquely upon a screen. A ratio (Lo/Lp) of a diagonal size (Lo) of said screen and a distance (Lp) from a center of said reflection mirror to said screen is at least 2, and the second lens group includes a refractive lens having a negative power and a rotationally symmetric surface configuration.

Abstract: A projection type image display apparatus includes an image display element, a projection unit including a first lens group and a second lens group formed with a plural number of lenses, a reflection mirror configured to reflect light emitted from the second lens group thereon after the light passes through the first lens group so as to project the light on a screen obliquely, and a mechanism configured to enable movement of at least one lens of the second lens group in a direction of an optical axis. The first lens group is fixed with respect to a bottom portion of the mechanism and is configured to compensate for an aberration of an optical system thereof. The second lens group is configured to enable movement of at least one lens of the second lens group with respect to the first lens group and the bottom portion of the mechanism.

Abstract: There is provided a projection image display apparatus which is excellent in quality of a display screen image even if a projection lens using a plastic lens having an asymmetrical shape with respect to an optical axis is used. The apparatus includes a projection lens which obliquely projects video light on a screen, an integrator which aligns a polarization direction of light from a light source, and an image display element (P, PL) which modulates light having the aligned polarization direction by an image signal. The projection lens includes multiple plastic lenses, and each of the multiple plastic lenses is arrayed, respectively, by shifting a gate direction to each other by 180 degrees. When the projection lens includes n sheets (n is a natural number) of plastic lenses, each of the multiple plastic lenses may be arrayed, respectively, by shifting a gate direction to each other by (360/n) degrees.

Abstract: In a projection type image display apparatus, for enlarging an image on a image display apparatus 1 by means of a projection lens 2, thereby projecting the enlarged image onto a screen 6, obliquely, being inclined thereto, between the projection lens 2 and a rear-surface mirror 5, there are disposed free shaped surface mirrors 3 and 4, each having a free shaped surface for compensating a trapezoidal distortion due to oblique projection of the enlarged image. The surface configuration of the free shaped surface mirror is so shaped as to satisfy a following equation: |L1?L2|>1.4·Dv if assuming that a distance for a light beam of an upper end of the enlarged image to reach the screen after being reflected upon a free shaped surface is “L1”, a distance for a light beam of a lower end of the enlarged image to reach the screen after being reflected upon the free shaped surface is “L2”, and a distance from an upper end of an image on the screen to a lower end thereof is “Dv”.

Abstract: A projection-type image display apparatus includes an enlarging projection optical unit which is configured to project an image displayed on an image display element enlargedly upon a display portion, a display controller portion which is configured to move a position of the image within a display surface of the image display element. The enlarging projection optical unit has a lens group for projecting the image enlargedly, wherein the display controller portion moves the image so as to display the image within the display surface of the image display element by projecting a portion selectively fitted to the display portion when displaying on the display portion through the enlarging projection optical unit.

Abstract: A projection type image display apparatus in which shortening of the projection distance (widening of the angle of view) and miniaturization of the projection optic system are realized is provided. It comprises, in a traveling direction of the light, an image display element, a lens group including a plurality of lenses, a first lens, a second lens, and a mirror to reflect light emitted from the second lens to be projected obliquely on a screen in this order. The refractive power of the first lens is positive and the refractive power of the second lens is negative. The first and the second lenses are moved in an interlocked relationship with each other along an optical axis of the lens group and a movement amount of the first lens is made larger than a movement amount of the second lens.

Abstract: A projection type display apparatus includes: a lens group comprising a plurality of lenses arranged in the traveling direction of light with respect to an image display element; a first lens arranged in the traveling direction of light with respect to the lens group; a second lens arranged in the traveling direction of light with respect to the first lens; and a mirror for reflecting light emitted from the second lens and obliquely projecting the reflected light onto a screen, wherein a lens, among the lens group, nearest to the first lens is a meniscus lens with its convex surface facing the direction of the first lens, wherein the first lens is a meniscus lens with its convex surface facing the direction of the second lens, and wherein the second lens is a meniscus lens with its convex surface facing the direction of the mirror.