Abstract: A projector includes a projection lens and a projector body. In the projection lens, a U-shaped optical path is formed by optical axis to optical axis. A lens barrel is a U-shaped barrel. A housing of the projector body includes a storage section. The projection lens is supported rotatably about the optical axis with respect to the housing, in an up-down direction and a right-left direction of the housing perpendicular to the optical axis, between a first position where the projection lens is stored inside a storage section provided in the housing and a second position where the projection lens is protruding from the housing.

Abstract: The projection optical system that projects an image, which is displayed on an image display surface on a reduction side, to a magnification side, in which at least one intermediate image is formed inside the projection optical system, and the projection optical system includes a first stop, of which an aperture diameter is variable, at a position closer to the reduction side than the intermediate image closest to the reduction side.

Abstract: The optical device projects an image, which is displayed on an image display surface on a reduction side, to a magnification side. The optical device includes: a first optical system; and a second optical system, in order from the magnification side to the reduction side along an optical path. The first optical system is an image forming optical system which is not telecentric on the reduction side, the second optical system is telecentric on the reduction side, the first optical system is housed in a first lens barrel, and the second optical system is housed in a second lens barrel, and an optical system on the optical path from a surface closest to the magnification side in the first optical system to a surface closest to the reduction side in the second optical system is shift-able with respect to the image display surface.

Abstract: The image forming optical system is capable of forming an image on a conjugated plane on a reduction side as an intermediate image and re-forming the intermediate image as a magnified image on a conjugated plane on a magnification side. The image forming optical system includes: a first adjustment group that moves along an optical axis in adjusting an image formation position of a region of the magnified image including a farthest point from the optical axis; and a second adjustment group that moves along the optical axis in adjusting an image formation position of a region of the magnified image including a nearest point from the optical axis. An optical element disposed closest to the magnification side is a lens. The second adjustment group has a positive refractive power as a whole, and is disposed closest to the reduction side.

Abstract: A projector includes a projection lens and a projector body. In the projection lens, a U-shaped optical path is formed by optical axis to optical axis. A lens barrel is a U-shaped barrel. A housing of the projector body includes a storage section. The projection lens is supported rotatably about the optical axis with respect to the housing, in an up-down direction and a right-left direction of the housing perpendicular to the optical axis, between a first position where the projection lens is stored inside a storage section provided in the housing and a second position where the projection lens is protruding from the housing.

Abstract: A projection-type display device includes: a display element including a rectangular displayable region in which an image is displayable; and a projection optical system. Assuming that a focal length of the projection optical system is f and a length of a long side of the displayable region is w, 0.15<|f|/w<0.45 is satisfied. An absorption layer that absorbs light is provided in at least a portion of a non-optically effective surface of a lens which is disposed closer to a reduction side than a first lens closest to an enlargement side in the projection optical system and at least a part of a portion which is irradiated with light that has been emitted from an image and reflected by an enlargement-side surface of the first lens or a reduction-side surface of the first lens.

Abstract: A zoom lens forms an intermediate image at a position conjugate to a reduction side imaging plane and forms the intermediate image again on a magnification side imaging plane. The zoom lens includes a plurality of lens groups including at least two movable lens groups, which move by changing spacings between the groups adjacent to each other in a direction of an optical axis during zooming, at a position closer to the reduction side than the intermediate image. Among the plurality of lens groups, a final lens group closest to the reduction side has a positive refractive power, and remains stationary with respect to the reduction side imaging plane during zooming. The zoom lens satisfies predetermined conditional expressions (1) and (2) about the focal lengths of the movable lens groups.

Abstract: The imaging optical system consists of a first optical system and a second optical system in order from a magnified side. The second optical system forms an image on an image display surface as an intermediate image, and the first optical system forms the intermediate image on a magnified-side conjugate plane. A height of a principal ray of light having a maximum angle of view becomes maximum on a lens surface of the whole system on the most magnified side, among heights of principal rays of light having a maximum angle of view on respective lens surfaces. The imaging optical system satisfies predetermined conditional expressions.

Abstract: The imaging optical system consists of a first optical system and a second optical system in order from a magnified side. The second optical system forms an image on an image display surface as an intermediate image, and the first optical system forms the intermediate image on a magnified-side conjugate plane. A height of a principal ray of light having a maximum angle of view becomes maximum on a lens surface of the whole system on the most magnified side, among heights of principal rays of light having a maximum angle of view on respective lens surfaces. The imaging optical system satisfies predetermined conditional expressions.

Abstract: A first holding barrel, a first mirror bending a first optical axis of the first holding barrel at 90°, a second holding barrel, a second mirror bending a second optical axis of the second holding barrel at 90°, and a third holding barrel are disposed on an optical axis from a screen side to an image forming panel. A first connection member connects the first holding barrel including the first mirror to the second holding barrel to be rotationally movable in increments of 90°. A second connection member connects the second holding barrel and the second mirror to the third holding barrel to be rotationally movable in increments of 90°. An orientation of a display image of the image forming panel is changed based on rotational movement states of an optical axis of a first sensor and an optical axis of a second sensor to make an orientation of a projection image on the screen match an original image.

Abstract: A projection lens having an optical system includes: an incidence lens on which light from an electrooptic element is incident; and an emission lens that is positioned closest to a magnification side and emits an image toward a projection surface, in which an incidence optical axis of the incidence lens is shifted in a first direction orthogonal to the incidence optical axis with respect to a center of a screen of the electrooptic element, a projection angle, which is an angle of an emission optical axis of the emission lens with respect to the projection surface, is less than 90°, and assuming that an effective diameter of the emission lens is DE, and a focal length of an entire optical system including the emission lens is f, and a half angle of view of the entire optical system is ?, ? is equal to or greater than 60°, and a value of PA defined by Expression (1) is equal to or greater than 0.1 and equal to or less than 7.

Abstract: A zoom lens forms an intermediate image at a position conjugate to a reduction side imaging plane and forms the intermediate image again on a magnification side imaging plane. The zoom lens includes a plurality of lens groups including at least two movable lens groups, which move by changing spacings between the groups adjacent to each other in a direction of an optical axis during zooming, at a position closer to the reduction side than the intermediate image. Among the plurality of lens groups, a final lens group closest to the reduction side has a positive refractive power, and remains stationary with respect to the reduction side imaging plane during zooming. The zoom lens satisfies predetermined conditional expressions (1) and (2) about the focal lengths of the movable lens groups.

Abstract: A projection-type display device includes: a display element including a rectangular displayable region in which an image is displayable; and a projection optical system. Assuming that a focal length of the projection optical system is f and a length of a long side of the displayable region is w, 0.15<|f|/w<0.45 is satisfied. An absorption layer that absorbs light is provided in at least a portion of a non-optically effective surface of a lens which is disposed closer to a reduction side than a first lens closest to an enlargement side in the projection optical system and at least a part of a portion which is irradiated with light that has been emitted from an image and reflected by an enlargement-side surface of the first lens or a reduction-side surface of the first lens.

Abstract: An imaging optical system includes a plurality of lenses, and the plurality of lenses includes a lens pair consisting of two lenses arranged near each other, in which radii of curvature of two surfaces arranged near each other is close to each other, and which satisfies predetermined conditional expressions.

Abstract: The imaging optical system forms a first intermediate image at a position conjugate to a magnification side imaging surface and a second intermediate image at a position closer to a reduction side than the first intermediate image on an optical path and conjugate to the first intermediate image. The imaging optical system consists of a first optical system, a second optical system, and a third optical system in order from the magnification side to the reduction side along the optical path. The imaging optical system does not include a reflective member having a power.

Abstract: A zoom lens forms an intermediate image at a position conjugate to a reduction side imaging plane and forms the intermediate image again on a magnification side imaging plane. The zoom lens includes a plurality of lens groups including at least two movable lens groups, which move by changing spacings between the groups adjacent to each other in a direction of an optical axis during zooming, at a position closer to the reduction side than the intermediate image. Among the plurality of lens groups, a final lens group closest to the reduction side has a positive refractive power, and remains stationary with respect to the reduction side imaging plane during zooming. The zoom lens satisfies predetermined conditional expressions (1) and (2) about the focal lengths of the movable lens groups.

Abstract: The projection optical system forms an intermediate image of an image displayed on an image display surface and forms a magnified image by projecting the intermediate image. The projection optical system consists of a first optical system and a second optical system, in order from the reduction side to the magnification side. The first optical system is telecentric on the magnification side, is a coaxial system having a common first optical axis and is non-telecentric on the reduction side. The second optical system is a coaxial system having a common second optical axis and is telecentric on the reduction side. The first optical axis and the second optical axis are parallel.

Abstract: A projector includes a projection lens and a projector body. In the projection lens, a U-shaped optical path is formed by optical axis to optical axis. A lens barrel is a U-shaped barrel. A housing of the projector body includes a storage section. The projection lens is supported rotatably about the optical axis with respect to the housing, in an up-down direction and a right-left direction of the housing perpendicular to the optical axis, between a first position where the projection lens is stored inside a storage section provided in the housing and a second position where the projection lens is protruding from the housing.

Abstract: A projector includes a projection lens and a projector body. In the projection lens, a U-shaped optical path is formed by optical axis to optical axis. A lens barrel is a U-shaped barrel. A housing of the projector body includes a storage section. The projection lens is supported rotatably about the optical axis with respect to the housing, in an up-down direction and a right-left direction of the housing perpendicular to the optical axis, between a first position where the projection lens is stored inside a storage section provided in the housing and a second position where the projection lens is protruding from the housing.

Abstract: The imaging optical system consists of a first optical system and a second optical system in order from a magnified side. The second optical system forms an image on an image display surface as an intermediate image, and the first optical system forms the intermediate image on a magnified-side conjugate plane. A height of a principal ray of light having a maximum angle of view becomes maximum on a lens surface of the whole system on the most magnified side, among heights of principal rays of light having a maximum angle of view on respective lens surfaces, to satisfy the following predetermined Conditional Expressions (1) and (2). 0.03<H×|f|/(L×I)<0.09 . . . ??(1) 0.35<I/dl . . .