Abstract: A free-form surface lens is made of a transparent resin forming an oblique projection optical system including a free-form surface mirror in a projection type video display apparatus, this lens includes a lens effective region having a surface on which a predetermined free-form surface is formed, and an edge surface formed to surround the lens effective region, the lens effective region and the edge surface in a part of a circumference surrounding the lens effective region where the edge surface is not formed are joined to each other by at least either one of a curved surface and a flat surface set so as not to change a direction of a tilt of the lens effective region in vicinity of the lens effective region, and an end surface including at least either one of the curved surface and the flat surface is set as a tapered surface.

Abstract: A projection type image display device includes an oblique projection optical system that magnifies and projects modulated image light, and includes lens elements and a reflection mirror having a convex surface. A center of an outer shape of one or more of the lens elements at a nearest position to the reflection mirror is positioned above an optical axis. The reflection mirror has a reflection surface shape orthogonal to a projection plane inclusive of the optical axis of the reflection mirror. The reflection surface shape and lens element are formed as specified. For example, the reflection surface shape is formed so that an average radius of curvature in an area through which a light flux focused at a center of the projection plane passes is smaller than that of curvature in an area through which a light flux focused at an upper end portion of the projection plane passes.

Abstract: A free-form surface lens is made of a transparent resin forming an oblique projection optical system including a free-form surface mirror in a projection type video display apparatus, this lens includes a lens effective region having a surface on which a predetermined free-form surface is formed, and an edge surface formed to surround the lens effective region, the lens effective region and the edge surface in a part of a circumference surrounding the lens effective region where the edge surface is not formed are joined to each other by at least either one of a curved surface and a flat surface set so as not to change a direction of a tilt of the lens effective region in vicinity of the lens effective region, and an end surface including at least either one of the curved surface and the flat surface is set as a tapered surface.

Abstract: A free-form surface lens is made of a transparent resin forming an oblique projection optical system including a free-form surface mirror in a projection type video display apparatus, this lens includes a lens effective region having a surface on which a predetermined free-form surface is formed, and an edge surface formed to surround the lens effective region, the lens effective region and the edge surface in a part of a circumference surrounding the lens effective region where the edge surface is not formed are joined to each other by at least either one of a curved surface and a flat surface set so as not to change a direction of a tilt of the lens effective region in vicinity of the lens effective region, and an end surface including at least either one of the curved surface and the flat surface is set as a tapered surface.

Abstract: A projection type image display device includes an oblique projection optical system that magnifies and projects modulated image light, and includes lens elements and a reflection mirror having a convex surface. A center of an outer shape of one or more of the lens elements at a nearest position to the reflection mirror is positioned above an optical axis. The reflection mirror has a reflection surface shape orthogonal to a projection plane inclusive of the optical axis of the reflection mirror. The reflection surface shape and lens element are formed as specified. For example, the reflection surface shape is formed so that an average radius of curvature in an area through which a light flux focused at a center of the projection plane passes is smaller than that of curvature in an area through which a light flux focused at an upper end portion of the projection plane passes.

Abstract: A free-form surface lens is made of a transparent resin forming an oblique projection optical system including a free-form surface mirror in a projection type video display apparatus, this lens includes a lens effective region having a surface on which a predetermined free-form surface is formed, and an edge surface formed to surround the lens effective region, the lens effective region and the edge surface in a part of a circumference surrounding the lens effective region where the edge surface is not formed are joined to each other by at least either one of a curved surface and a flat surface set so as not to change a direction of a tilt of the lens effective region in vicinity of the lens effective region, and an end surface including at least either one of the curved surface and the flat surface is set as a tapered surface.