Abstract: The present disclosure provides an optical system that includes a prism having an incident surface, an exit surface, and one or more reflecting surfaces. A first intermediate imaging position of a light flux in a first direction is located inside the prism. The first intermediate imaging position is different from a second intermediate imaging position of the light flux in a second direction orthogonal to the first direction.

Abstract: An optical system according to the present disclosure includes a first sub-optical system including an aperture stop and a second sub-optical system including a prism. The prism has a first transmission surface located on the reduction side, a second transmission surface located on the magnification side, and at least one reflection surface located on the optical path between the first transmission surface and the second transmission surface. A first reflection surface closest to the intermediate imaging position has a shape with a concave surface facing a direction into which a light ray incident on first the reflection surface is reflected. A curvature shape of the first reflection surface is set such that some of multiple principal rays passing through the reduction conjugate point intersect on the optical path between the first reflection surface and the second transmission surface.

Abstract: An optical system according to the present disclosure includes a first sub-optical system including an aperture stop and a second sub-optical system including a prism. The prism has a first transmission surface located on the reduction side, a second transmission surface located on the magnification side, and at least one reflection surface located on the optical path between the first transmission surface and the second transmission surface. A first reflection surface closest to the intermediate imaging position has a shape with a concave surface facing a direction into which a light ray incident on first the reflection surface is reflected. A curvature shape of the first reflection surface is set such that some of multiple principal rays passing through the reduction conjugate point intersect on the optical path between the first reflection surface and the second transmission surface.

Abstract: The present disclosure provides an optical system that includes a prism having an incident surface, an exit surface, and one or more reflecting surfaces. The optical system includes a first scanning element configured to scan in a first direction a light that enters and reflect the light in a direction of the incident surface of the prism, and a second scanning element configured to scan in a second direction the light that exits from the exit surface of the prism, the second direction being orthogonal to the first direction. The incident surface of the prism has a convex shape with respect to the first scanning element.

Abstract: The present disclosure is directed to an optical system having a reduction conjugate point on a reduction side and a magnification conjugate point on a magnification side, and internally having an intermediate imaging position having a conjugate relationship with each of the reduction conjugate point and the magnification conjugate point, the optical system including: a prism provided on the magnification side, the prism formed of a transparent medium; and a sub-optical system provided between the reduction conjugate point and the prism, the sub-optical system, wherein the prism includes a first transmission surface positioned on the reduction side, a second transmission surface positioned on the magnification side, and at least one reflection surface positioned therebetween, wherein the following Expression is satisfied: 0.40<(TN?((NI?1)/8))/PN2<0.64.

Abstract: The present disclosure provides an optical system that includes a prism having an incident surface, an exit surface, and one or more reflecting surfaces. The optical system includes a first scanning element configured to scan a light that enters and has a plurality of wavelengths in a first direction, and reflect the light in a direction of the incident surface of the prism. The optical system includes a second scanning element configured to scan in a second direction the light that exits from the exit surface of the prism, the second direction being orthogonal to the first direction. The incident surface of the prism has a concave shape with respect to the first scanning element.

Abstract: The optical system includes a first sub-optical system including an aperture stop and a second sub-optical system including a prism. The prism has a first transmission surface located on a reduction side, a second transmission surface located on a magnification side, and at least one reflection surface between the first transmission surface and the second transmission surface. The first sub-optical system includes a plurality of rotationally symmetric lens elements.

Abstract: An optical device includes a lens element, a first scanning element, and a controller. The lens element directs first light emitted from the first light-emitting element and second light emitted from the second light-emitting element, to a predetermined position. The first scanning element is arranged at the predetermined position, on which first light and second light exiting the lens element are incident at mutually different angles. The controller provides light emission control to start light emission at light emission timings shifted. The first light-emitting element and the second light-emitting element is arrayed such that an optical axis of first light and an optical axis of second light are contained in a same plane. The controller controlees the light emission timings of the first light-emitting element and the second light-emitting element in response to rotation actions of the first scanning element.

Abstract: A prism includes a first intermediate imaging position at which a component in a first direction of the light flux is imaged and a second intermediate imaging position at which a component in a second direction orthogonal to the first direction of the light flux is imaged, different from the first intermediate imaging position. At least one of the first intermediate imaging position and the second intermediate imaging position lying within a first range from the second surface between the first surface and the second surface or lying within a second range from the second surface between the second surface and the third surface. The first range has a length less than one-half of an optical path length from the first surface to the second surface, and the second range has a length less than one-half of the optical path length from the second surface to the third surface.

Abstract: An optical system according to the present disclosure includes a first sub-optical system including an aperture stop and a second sub-optical system including a prism. The prism has a first transmission surface located on the reduction side, a second transmission surface located on the magnification side, and at least one reflection surface located on the optical path between the first transmission surface and the second transmission surface. A first reflection surface closest to the intermediate imaging position has a shape with a concave surface facing a direction into which a light ray incident on first the reflection surface is reflected. A curvature shape of the first reflection surface is set such that some of multiple principal rays passing through the reduction conjugate point intersect on the optical path between the first reflection surface and the second transmission surface.

Abstract: The present disclosure provides an optical system that includes a prism having an incident surface, an exit surface, and one or more reflecting surfaces. The optical system includes a first scanning element configured to scan in a first direction a light that enters and reflect the light in a direction of the incident surface of the prism, and a second scanning element configured to scan in a second direction the light that exits from the exit surface of the prism, the second direction being orthogonal to the first direction. The incident surface of the prism has a convex shape with respect to the first scanning element.

Abstract: The present disclosure provides an optical system that includes a prism having an incident surface, an exit surface, and one or more reflecting surfaces. A first intermediate imaging position of a light flux in a first direction is located inside the prism. The first intermediate imaging position is different from a second intermediate imaging position of the light flux in a second direction orthogonal to the first direction.

Abstract: An image projection device includes an image display element that forms a projection image, a transmissive optical system that is disposed on an emission surface side of the image display element and includes a diaphragm and a plurality of lenses, and a reflection optical system that includes a first mirror reflecting light emitted from the transmissive optical system and having positive power and a second mirror that is a plane mirror for reflecting light reflected by the first mirror on a projection surface. The first mirror is disposed between the second mirror and the projection surface in a direction along an optical axis of the transmissive optical system. An intermediate image is formed between the transmissive optical system and the first mirror.

Abstract: The present disclosure provides an optical system that includes a prism having an incident surface, an exit surface, and one or more reflecting surfaces. The optical system includes a first scanning element configured to scan a light that enters and has a plurality of wavelengths in a first direction, and reflect the light in a direction of the incident surface of the prism. The optical system includes a second scanning element configured to scan in a second direction the light that exits from the exit surface of the prism, the second direction being orthogonal to the first direction. The incident surface of the prism has a concave shape with respect to the first scanning element.

Abstract: A projection optical system is a projection optical system for projecting an image in an image display element on a projection target surface in an enlarged manner, and includes a transmissive optical system and a reflection optical system. The transmissive optical system includes a plurality of lenses and an aperture diaphragm. The reflection optical system includes a first reflecting surface that reflects light emitted from the transmissive optical system and a second reflecting surface that reflects light emitted from the first reflecting surface. A principal ray of the reference rays is a ray passing through a center of the aperture diaphragm among the reference rays. Local power of the first reflecting surface at a position where the principal ray enters the first reflecting surface is larger than local power of the second reflecting surface at a position where the principal ray enters the second reflecting surface.

Abstract: An image projection device includes an image display element that forms a projection image, a transmissive optical system that is disposed on an emission surface side of the image display element and includes a diaphragm and a plurality of lenses, and a reflection optical system that includes a first mirror reflecting light emitted from the transmissive optical system and having positive power and a second mirror that is a plane mirror for reflecting light reflected by the first mirror on a projection surface. The first mirror is disposed between the second mirror and the projection surface in a direction along an optical axis of the transmissive optical system. An intermediate image is formed between the transmissive optical system and the first mirror.

Abstract: A projection optical system is a projection optical system for projecting an image in an image display element on a projection target surface in an enlarged manner, and includes a transmissive optical system and a reflection optical system. The transmissive optical system includes a plurality of lenses and an aperture diaphragm. The reflection optical system includes a first reflecting surface that reflects light emitted from the transmissive optical system and a second reflecting surface that reflects light emitted from the first reflecting surface. A principal ray of the reference rays is a ray passing through a center of the aperture diaphragm among the reference rays. Local power of the first reflecting surface at a position where the principal ray of the reference rays enters the first reflecting surface is larger than local power of the second reflecting surface at a position where the principal ray of the reference rays enters the second reflecting surface.

Abstract: A projection optical system is an optical system for projecting an image light flux formed in an image display element onto a projection surface, and includes a transmission optical system and a reflection optical system. The transmission optical system is located on an emission surface side of the image display element and includes a stop and a plurality of lenses. The reflection optical system includes a positive-power first mirror and a second mirror. Conditional Expression (1) is satisfied 0<TL/ft<10??(1) where ft is a focal length of the transmission optical system, and TL is a distance parallel to an optical axis of the transmission optical system from a position where the first mirror reflects a principal ray of the image light flux, to the image display element.

Abstract: A projection optical system is an optical system that magnifies and projects an image onto a projection surface from an oblique position defined by a Y-axis and a Z-axis. The image is displayed on an image display element, is defined by a positive direction of an X-axis and a positive direction of the Y-axis, and includes a long side parallel to the X-axis and a short side parallel to the Y-axis when a positional relationship is expressed using an XYZ coordinate. The projection optical system includes a transmission optical system and a transmission element. An incident angle of a light beam of the image incident on a reference vertical intersecting line with respect to one of surfaces of the transmission element is zero only at one point on the reference vertical intersecting line.

Abstract: A projection optical system is an optical system for projecting an image light flux formed in an image display element onto a projection surface, and includes a transmission optical system and a reflection optical system. The transmission optical system is located on an emission surface side of the image display element and includes a stop and a plurality of lenses. The reflection optical system includes a positive-power first mirror and a second mirror. Conditional Expression (1) is satisfied 0<TL/ft<10 ??(1) where ft is a focal length of the transmission optical system, and TL is a distance parallel to an optical axis of the transmission optical system from a position where the first mirror reflects a principal ray of the image light flux, to the image display element.