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: An imaging optical system consists of, in order from a magnification side: a first optical system that forms an intermediate image on a position conjugate to a magnification side imaging surface; and a second optical system that re-forms the intermediate image on a reduction side imaging surface. The first optical system includes at least two focusing lens groups that move with different loci during focusing. The imaging optical system satisfies predetermined conditional expressions relating to the focusing lens groups.

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: The imaging optical system consists of first and second optical systems in order from a magnified side. The second optical system forms an image on an image display surface as an intermediate image. The first optical system forms the intermediate image on a magnified-side conjugate plane. A height H of a principal ray of light having a maximum angle of view becomes maximum on a lens surface of the whole system (having focal length f) on the most magnified side, among heights of principal rays of light having a maximum angle of view on respective lens surfaces, satisfying predetermined Conditional Expressions (1) and (2): 0.03<H×|f|/(L×I)<0.09??(1) 0.35<I/dl??(2) Where L is an optical axis distance between lens surfaces on the most magnified and reduced sides, I is a reduced side maximum image height, and dl is a maximum air spacing on the optical axis within the system.

Abstract: A projection lens, which is a projection lens to be attached to a projection apparatus body having an electro-optical device, includes: a zoom optical system including a plurality of lenses; a first holding portion that is to be connected to the projection apparatus body and through which light along a first optical axis passes; and a second holding portion through which light along a second optical axis, which is bent with respect to the first optical axis, passes and that is rotatable relative to the first holding portion. The zoom optical system is held by the first holding portion.

Abstract: The imaging optical system consists of, in order from a magnification side: a first imaging optical system that forms an intermediate image on a position conjugate to a magnification side imaging surface; and a second imaging optical system that re-forms the intermediate image on a reduction side imaging surface. The first imaging optical system consists of, in order from the magnification side, a first A lens group, a first optical path deflection unit that deflects an optical path, a first B lens group, and a second optical path deflection unit that deflects the optical path. In addition, the intermediate image is formed between the second optical path deflection unit and the second imaging optical system.

Abstract: A first optical system, a first mirror, a second optical system, a second mirror, and a third optical system are disposed in order on an optical axis from an image forming panel to a screen. A first optical axis of the first optical system, a second optical axis of the second optical system, and a third optical axis of the third optical system are formed in a U shape, and orientations of luminous fluxes of the first optical axis and the third optical axis are reversed. The first mirror, the second optical system, the second mirror, and the third optical system are held to make a second holding barrel with respect to the first optical system. The second holding barrel is rotationally moved in a rotational movement range of 45° with respect to a first holding barrel. In projecting portrait image instead of a landscape image, the second holding barrel is rotated in increments of 45° with respect to the first holding barrel.

Abstract: An imaging optical system consists of a first lens group and a second lens group, in order from a magnification side along an optical axis, an intermediate image is formed between the first lens group and the second lens group on the optical axis, at least one of the first lens group or the second lens group includes a reflector that bends the optical axis, the second lens group includes a movable lens group that moves during zooming, and predetermined conditional expressions are satisfied.

Abstract: The imaging optical system forms a first intermediate image at a position conjugate to the 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 a magnification side to the reduction side along the optical path. The imaging optical system is configured to be telecentric on the reduction side. The imaging optical system satisfies predetermined conditional expressions.

Abstract: The imaging optical system forms a first intermediate image at a position conjugate to the 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 a magnification side to the reduction side along the optical path. The imaging optical system is configured to be telecentric on the reduction side. The imaging optical system 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: The imaging optical system consists of, in order from the magnification side, a first optical system forming an intermediate image and a second optical system re-forming the intermediate image, and is configured to be telecentric on the reduction side. The imaging optical system satisfies predetermined conditional expressions relating to a ray height on a lens surface closest to the magnification side in the second optical system, a ray height on a lens surface closest to the reduction side in the first optical system, and heights of rays at a position where a principal ray with the maximum angle of view intersects with the optical axis in the second optical system.

Abstract: The imaging lens includes at least one negative lens that satisfies predetermined Conditional Expressions (1) to (3) indicating conditions in which dispersion is relatively low and refractive index is high while having a negative rate of change of the refractive index. A positive lens having a largest Abbe number at the d line among positive lenses included in the imaging lens satisfies predetermined Conditional Expressions (4) and (5).

Abstract: The wide-angle lens consists of a projection lens which is disposed closer to a magnified side than an intermediate image, and a relay lens which is disposed closer to a reduced side than the intermediate image and is configured to be attachable and detachable to and from the projection lens, and satisfies the following Conditional Expressions (1) and (2) 0<|FC/FC2|<0.2??(1) 0.

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 first optical system, a first mirror, a second optical system, a second mirror, and a third optical system are disposed in order on an optical axis from an image forming panel to a screen. A first optical axis of the first optical system, a second optical axis of the second optical system, and a third optical axis of the third optical system are formed in a U shape, and orientations of luminous fluxes of the first optical axis and the third optical axis are reversed. The first mirror, the second optical system, the second mirror, and the third optical system are held to make a second holding barrel with respect to the first optical system. The second holding barrel is rotationally moved in a rotational movement range of 45° with respect to a first holding barrel. In projecting portrait image instead of a landscape image, the second holding barrel is rotated in increments of 45° with respect to the first holding barrel.

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: The imaging optical system consists of, in order from a magnification side along an optical axis: a first lens group; a first optical axis deflection unit that deflects the optical axis; a second lens group; a second optical axis deflection unit that deflects the optical axis; and a third lens group. The imaging optical system forms an intermediate image between the first optical axis deflection unit and a surface closest to the magnification side in the first lens group.

Abstract: An imaging optical system consists of a first lens group and a second lens group, in order from a magnification side along an optical axis, an intermediate image is formed between the first lens group and the second lens group on the optical axis, at least one of the first lens group or the second lens group includes a reflector that bends the optical axis, the second lens group includes a movable lens group that moves during zooming, and predetermined conditional expressions are satisfied.

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.