Abstract: A projection system is formed of a first optical system and a second optical system sequentially arranged from the demagnifying side toward the magnifying side and forms a first intermediate image and a second intermediate image in positions between a demagnifying-side image formation plane and a magnifying-side image formation plane of the projection system. The second optical system is a lens. The lens has a first transmissive surface, a reflective surface, and a second transmissive surface. The reflective surface has a concave shape, and the second transmissive surface has a convex shape protruding toward the magnifying side. An imaginary line specified in the lens inclines with respect to an imaginary vertical line perpendicular to the imaginary axis in a plane YZ, and the intermediate image is located between the first transmissive surface and the reflective surface.

Abstract: A projection system includes a first optical system and a second optical system including an optical element and disposed on the enlargement side of the first optical system. The optical element has a first transmissive surface, a first reflection surface disposed on the enlargement side of the first transmissive surface, a second reflection surface disposed on the enlargement side of the first reflection surface, and a second transmissive surface disposed on the enlargement side of the second reflection surface. The second reflection surface has a concave shape. A first optical axis of the first optical system and a second optical axis of the second reflection surface intersect each other.

Abstract: A projection system includes a first optical system including a plurality of lenses and a deflector, and a second optical system including an optical element having a concave reflection surface and disposed at the enlargement side of the first optical system. The deflector is disposed in one air gap of a plurality of air gaps provided between the lenses adjacent to each other in the first optical system, the air gap having the largest axial inter-surface distance in the first optical system. The first optical system includes a first section located at the reduction side of the deflector and a second section located at the enlargement side of the deflector. A first optical axis section of the first section and a second optical axis section of the second section intersect each other. The second section includes three or more lenses. The second section is shorter than the first section.

Abstract: A projection system includes a first and second optical system including an optical element and disposed at the enlargement side of the first optical system. The optical element has a first transmissive surface, a reflection surface, and a second transmissive surface. The second transmissive surface has a convex shape an aspheric shape. An effective light ray range of the second transmissive surface has a first end close to an optical axis of the reflection surface in a first axis direction along a first axis perpendicular to the optical axis and a second end far from the optical axis. A first radius of curvature at the first end is greater than a second radius of curvature at the second end, and a first center of curvature of the first radius of curvature is farther than a second center of curvature of the second radius of curvature from the first end.

Abstract: A projection system has a first optical system and a second optical system arranged on a magnifying side of the first optical system. The projection system forms an intermediate image in a position between a demagnifying-side image formation plane and a magnifying-side image formation plane of the projection system. The second optical system is an optical element having a first transmissive surface, a reflective surface, and a second transmissive surface arranged from a demagnifying side toward the magnifying side. The first transmissive surface and the reflective surface are located at one side with respect to an optical axis. The second transmissive surface is located at another side with respect to the optical axis. The reflective surface has a concavely curved shape. The second transmissive surface has a convexly curved shape protruding toward the magnifying side.

Abstract: A projection optical system has first and second optical systems disposed in order from a demagnification side toward a magnification side. An intermediate image is formed between demagnification-side and magnification-side imaging surfaces. The second optical system is an optical element having first transmission, reflecting, and second transmission surfaces in order from the demagnification toward the magnification sides. The first transmission and reflecting surfaces are located at one side with respect to an optical axis. The second transmission surface is located at the other side with respect to the optical axis. The reflecting surface has a concavely curved surface shape. The second transmission surface has a convexly curved surface shape protruding toward the magnification side. The optical element has a first member and a second member different in refractive index from the first member. A bonding surface between the first member and the second member has a curved surface shape.

Abstract: A projection optical system has a first optical system and a second optical system. The first and second optical systems are disposed in order from a demagnification side toward a magnification side. An intermediate image is formed between a demagnification-side imaging surface and a magnification-side imaging surface. The second optical system is an optical element having a first transmission surface, reflecting surface, and second transmission surface in order from the demagnification side toward the magnification side. The first transmission surface and reflecting surface are located at one side, and the second transmission surface is located at the other side with respect to the optical axis. The reflecting surface has a concavely curved surface shape. The second transmission surface has a convexly curved surface shape protruding toward the magnification side. The optical element has a first member and a second member different in refractive index.

Abstract: A projection system includes a first optical system and a second optical system including an optical element and disposed at the enlargement side of the first optical system. The first optical system includes a first lens and a second lens disposed at the reduction side of the first lens. The optical element has a first transmissive surface, a reflection surface disposed at the enlargement side of the first transmissive surface, and a second transmissive surface disposed at the enlargement side of the reflection surface. The first lens has aspheric surfaces at opposite sides. The second lens has aspheric surfaces at opposite sides. At least one of the first and second lenses is configured to move in an optical axis direction along a first optical axis of the first optical system.

Abstract: A projection system is formed of a first optical system and a second optical system sequentially arranged from the demagnifying side and forms an intermediate image in a position between a demagnifying-side image formation plane and a magnifying-side image formation plane of the projection system. The second optical system is a lens. The lens has a first transmissive surface, a reflective surface, and a second transmissive surface sequentially arranged from the demagnifying side toward the magnifying side. The reflective surface has a concave shape, and the second transmissive surface has a convex shape protruding toward the magnifying side. An imaginary line specified in the lens inclines with respect to an imaginary vertical line perpendicular to the imaginary axis in a plane YZ, and the intermediate image is located in the lens between the first transmissive surface and the reflective surface.

Abstract: An optical element has a first member having a first refractive index and a second member having a second refractive index different from the first refractive index. The optical element has a first transmissive surface, a reflective surface, and a second transmissive surface arranged from a demagnifying side toward a magnifying side in order. The first transmissive surface and the reflective surface are located in one side with respect to an optical axis of the optical element. The second transmissive surface is located in the other side with respect to the optical axis of the optical element. the reflective surface has a concave shape.

Abstract: A projection optical system has first and second optical systems disposed in order from a demagnification side toward a magnification side. An intermediate image is formed between demagnification-side and magnification-side imaging surfaces. The second optical system is an optical element having first transmission, reflecting, and second transmission surfaces in order from the demagnification toward the magnification sides. The first transmission and reflecting surfaces are located at one side with respect to an optical axis. The second transmission surface is located at the other side with respect to the optical axis. The reflecting surface has a concavely curved surface shape. The second transmission surface has a convexly curved surface shape protruding toward the magnification side. The optical element has a first member and a second member different in refractive index from the first member. A bonding surface between the first member and the second member has a curved surface shape.

Abstract: A projection optical system has a first optical system and a second optical system. The first and second optical systems are disposed in order from a demagnification side toward a magnification side. An intermediate image is formed between a demagnification-side imaging surface and a magnification-side imaging surface. The second optical system is an optical element having a first transmission surface, reflecting surface, and second transmission surface in order from the demagnification side toward the magnification side. The first transmission surface and reflecting surface are located at one side, and the second transmission surface is located at the other side with respect to the optical axis. The reflecting surface has a concavely curved surface shape. The second transmission surface has a convexly curved surface shape protruding toward the magnification side. The optical element has a first member and a second member different in refractive index.

Abstract: A projection system has a first optical system and a second optical system arranged on a magnifying side of the first optical system. The projection system forms an intermediate image in a position between a demagnifying-side image formation plane and a magnifying-side image formation plane of the projection system. The second optical system is an optical element having a first transmissive surface, a reflective surface, and a second transmissive surface arranged from a demagnifying side toward the magnifying side. The first transmissive surface and the reflective surface are located at one side with respect to an optical axis. The second transmissive surface is located at another side with respect to the optical axis. The reflective surface has a concavely curved shape. The second transmissive surface has a convexly curved shape protruding toward the magnifying side.

Abstract: A projection system is formed of a first optical system and a second optical system sequentially arranged from the demagnifying side and forms an intermediate image in a position between a demagnifying-side image formation plane and a magnifying-side image formation plane of the projection system. The second optical system is a lens. The lens has a first transmissive surface, a reflective surface, and a second transmissive surface sequentially arranged from the demagnifying side toward the magnifying side. The reflective surface has a concave shape, and the second transmissive surface has a convex shape protruding toward the magnifying side. An imaginary line specified in the lens inclines with respect to an imaginary vertical line perpendicular to the imaginary axis in a plane YZ, and the intermediate image is located in the lens between the first transmissive surface and the reflective surface.

Abstract: A lens has a first transmissive surface, a reflective surface, and a second transmissive surface sequentially arranged from a demagnifying side toward a magnifying side. The first transmissive surface and the reflective surface are located at the lower side of an imaginary axis extending in an axis-Z direction, and the second transmissive surface is located at the upper side of the imaginary axis. The reflective surface has a concave shape, and the second transmissive surface has a convex shape protruding toward the magnifying side. An imaginary line that connects an upper intersection to a lower intersection inclines with respect to an imaginary vertical line perpendicular to the imaginary axis in a plane YZ.

Abstract: A projection system is formed of a first optical system and a second optical system sequentially arranged from the demagnifying side toward the magnifying side and forms a first intermediate image and a second intermediate image in positions between a demagnifying-side image formation plane and a magnifying-side image formation plane of the projection system. The second optical system is a lens. The lens has a first transmissive surface, a reflective surface, and a second transmissive surface. The reflective surface has a concave shape, and the second transmissive surface has a convex shape protruding toward the magnifying side. An imaginary line specified in the lens inclines with respect to an imaginary vertical line perpendicular to the imaginary axis in a plane YZ, and the intermediate image is located between the first transmissive surface and the reflective surface.

Abstract: A second group has different power in the vertical direction and the horizontal direction of the liquid crystal panel. Therefore, the horizontal-to-vertical ratio of the image of the liquid crystal panel and the horizontal-to-vertical ratio of the image projected on the screen can be set to be different. That is, the projection optical system is able to convert the aspect ratio which is a ratio of width and height. At this time, at the time of converting the aspect ratio, that is, at the time of switching the projection state, it is possible to adjust the position of the image on the screen through a zoom operation or a shift operation of the first driving mechanism or the fourth driving mechanism.

Abstract: A projector includes: a body including a light source, a display plane illuminated with light from the light source, and a projection optical system which projects light from the display plane; and a projection unit which projects the light from the display plane, which is projected from the projection optical system, toward an illumination-targeted plane, wherein the projection unit includes a negative power convex angle-widening mirror, and wherein the angle-widening mirror reflects light forming an image plane of the display plane for angle-widening, the image plane being inclined to the display plane.

Abstract: A projection system includes: a relay system that focuses light having exited through a first image plane on a second image plane; and an enlarging system that enlarges and projects an image focused on the second image plane on a third image plane, wherein the relay system includes a first lens element on which the light having exited through the first image plane is incident, the first lens element having positive refracting power, a reflective member that reflects a light having passed through the first lens element, the reflective member having positive refracting power, and a second lens element on which a light reflected off the reflective member is incident and which focuses the light reflected off the reflective member on the second image plane, the second lens element having positive refracting power.

Abstract: A projection lens includes, in order from an enlargement side, a first optical system, a second optical system, and a third optical system. At least a portion of an intermediate image is formed so as to overlap the second optical system.