Abstract: Provided is an observation apparatus including an image display element and an eyepiece optical system to be used to observe an image displayed on the image display element, in which the eyepiece optical system includes a plurality of lenses consisting of, in order from an image display plane side to an observation side, a first lens having a negative refractive power and a second lens having a positive refractive power, and in which a paraxial curvature radius of a lens surface on the image display plane side of the first lens, a paraxial curvature radius of a lens surface on the observation side of the first lens, a paraxial curvature radius of a lens surface on the image display plane side of the second lens, and a paraxial curvature radius of a lens surface on the observation side of the second lens are set appropriately.

Abstract: The present invention provides an eyepiece optical system for observing an image displayed on an image display surface. The eyepiece optical system includes a first lens having a positive refractive power, a second lens having a negative refractive power, and a third lens having a positive refractive power, which are arranged in this order from an image display surface side to an observation side. A focal length of the first lens, a focal length of the third lens, a curvature radius of a lens surface on the observation side of the first lens, and a curvature radius of a lens surface on the image display surface side of the second lens are appropriately set.

Abstract: Provided is an observation apparatus including an image display element and an eyepiece optical system to be used to observe an image displayed on the image display element, in which the eyepiece optical system includes a plurality of lenses consisting of, in order from an image display plane side to an observation side, a first lens having a negative refractive power and a second lens having a positive refractive power, and in which a paraxial curvature radius of a lens surface on the image display plane side of the first lens, a paraxial curvature radius of a lens surface on the observation side of the first lens, a paraxial curvature radius of a lens surface on the image display plane side of the second lens, and a paraxial curvature radius of a lens surface on the observation side of the second lens are set appropriately.

Abstract: The present invention provides an eyepiece optical system for observing an image displayed on an image display surface. The eyepiece optical system includes a first lens having a positive refractive power, a second lens having a negative refractive power, and a third lens having a positive refractive power, which are arranged in this order from an image display surface side to an observation side. A focal length of the first lens, a focal length of the third lens, a curvature radius of a lens surface on the observation side of the first lens, and a curvature radius of a lens surface on the image display surface side of the second lens are appropriately set.

Abstract: A manufacturing method uses a molding unit to manufacture lenses out of a structure with a plurality of lens intermediates coupled to each other through a runner. The molding unit includes a holding member provided with first opening parts and second opening parts coaxial with each other, and molding chambers. First molding dies and second molding dies are inserted into the first opening parts and the second opening parts respectively. The holding member is further provided with a path that allows introduction of the lens intermediates into the molding chambers. In a manufacturing process, the lens intermediates are guided to predetermined positions in the corresponding molding chambers by operating the structure to cause the lens intermediates and the runner to move along the path. Next, a pressing pressure is applied to the lens intermediates to form molded lenses.

Abstract: A composite lens of the present invention has a base lens and a resin lens placed on the base lens. The resin lens has, in an area outside an optically effective diameter, a first surface, a second surface that is adjacent to the first surface, and a third surface that is adjacent to the second surface in sequence from an optical axis to an outer circumference. The first surface has an inclined surface that becomes higher from the outer circumference toward the optical axis, and the inclined surface is connected to the second surface. The second surface has a plane that is substantially perpendicular to the optical axis, and the substantially perpendicular plane is connected to the first plane. The third surface has an inclined surface that becomes lower from an inner circumference toward the outer circumference.

Abstract: A composite lens of the present invention has a base lens and a resin lens placed on the base lens. The resin lens has, in an area outside an optically effective diameter, a first surface, a second surface that is adjacent to the first surface, and a third surface that is adjacent to the second surface in sequence from an optical axis to an outer circumference. The first surface has an inclined surface that becomes higher from the outer circumference toward the optical axis, and the inclined surface is connected to the second surface. The second surface has a plane that is substantially perpendicular to the optical axis, and the substantially perpendicular plane is connected to the first plane. The third surface has an inclined surface that becomes lower from an inner circumference toward the outer circumference.