Abstract: A lens for headlamps of vehicles provided with a diffraction grating on a surface, wherein a phase function of the diffraction grating is represented by ? ? ( r ) = ? i = 1 N ? ? ? 2 ? i ? r 2 ? i where r represents distance from the central axis of the lens, and the relationship |?2|·(0.3R)2<|?4|·(0.3R)4 is satisfied where R represents effective radius of the lens, and wherein a second derivative of the phase function has at least one extreme value and at least one point of inflection where r is greater than 30% of R, a difference in spherical aberration between the maximum value and the minimum value at any value of r in 0?r?R is equal to or less than the longitudinal chromatic aberration for visible light, the diffraction grating is at least partially on the surface where r is greater than 30%, and the relationship 1 < ? ? ? ( R ) R 2 ? < 10 is satisfied.

Abstract: An illumination optical system having a light source and a single convex lens with a diffractive structure, wherein the phase function of the diffractive structure is represented by ? ? ( r ) = ? i = 1 N ? ? ? 2 ? i ? r 2 ? i where r represents distance from the central axis of the lens, the relationship |?2|·(0.3R)2<|?4|·(0.3R)4 is satisfied where R represents effective radius of the lens, the second derivative of the phase function has at least one extreme value and at least one point of inflection where r is greater than 30% of R, and the area of a surface of the light source is equal to or greater than 3% of the area of the entrance pupil when the light source side of the lens is defined as the image side.

Abstract: An illumination optical system having a light source and a single convex lens with a diffractive structure, wherein the phase function of the diffractive structure is represented by ? ? ( r ) = ? i = 1 N ? ? ? 2 ? i ? r 2 ? i where r represents distance from the central axis of the lens, the relationship |?2|·(0.3R)2<|?4|·(0.3R)4 is satisfied where R represents effective radius of the lens, the second derivative of the phase function has at least one extreme value and at least one point of inflection where r is greater than 30% of R, and the area of a surface of the light source is equal to or greater than 3% of the area of the entrance pupil when the light source side of the lens is defined as the image side.

Abstract: The projector-type headlamp comprises a projection lens unit and a light source unit. A diffraction grating designed to eliminate chromatic aberrations is provided on at least part of a lens surface of the lens unit. When an x axis in the horizontal direction and a y axis in the vertical direction are defined on a plane perpendicular to the optical axis, R1 is the maximum y coordinate on the lens surface, and 0?A<1, an area of the lens surface in which y<A·R1 comprises a curved surface or a flat surface, at least partially provided with the diffraction grating, and an area of the lens surface in which y?A·R1 comprises a separate curved surface that has a power greater than the power of the curved surface or flat surface, and is not provided with a diffraction grating.

Abstract: An optical lens includes a first lens group with negative refractive power, a second lens group with positive refractive power, and an aperture stop disposed between the first lens group and the second lens group. A total number of lenses in the first lens group is less than three, and a total number of lenses in the second lens group is less than five. The second lens group includes a first lens, a second lens and a third lens arranged in order in a direction away from the aperture stop. Each of the first lens and the second lens is an aspheric lens, and one of the first lens and the second lens has a diffractive optical surface.

Abstract: A lens for headlamps of vehicles provided with a diffraction grating on a surface, wherein a phase function of the diffraction grating is represented by ? ? ( r ) = ? i = 1 N ? ? ? 2 ? i ? r 2 ? i where r represents distance from the central axis of the lens, and the relationship |?2|·(0.3R)2<|?4|·(0.3R)4 is satisfied where R represents effective radius of the lens, and wherein a second derivative of the phase function has at least one extreme value and at least one point of inflection where r is greater than 30% of R, a difference in spherical aberration between the maximum value and the minimum value at any value of r in 0?r?R is equal to or less than the longitudinal chromatic aberration for visible light, the diffraction grating is at least partially on the surface where r is greater than 30%, and the relationship 1 < ? ? ? ( R ) R 2 ? < 10 is satisfied.

Abstract: A microlens array, each microlens containing N sides of a convex polygon and N curved surfaces corresponding to the sides, wherein when the line passing through the microlens vertex and perpendicular to the polygon plane is z axis, the line passing through the intersection point (origin) between z axis and the plane and perpendicular to a side is x axis, z coordinate of the curved surface corresponding to the side is z=f(x), a distance from the origin to the side is t, a virtual curved surface in 0?|x|?t is z=F(x), refractive index of the microlens is no, A and C represents constants, and g ? ( x ) = dF ? ( x ) dx = - x ? x ? · Cx 2 + A n 0 ? 1 + ( Cx 2 + A ) 2 - 1 , ? g ? ( x ) - 0.035 ? df ? ( x ) dx ? g ? ( x ) + 0.035 is satisfied and f (x) is determined such that an illuminance distribution in an illuminated area is more uniform than that in the case that the curved surface is shaped in a segment of a circle.

Abstract: An optical imaging system according to the present invention includes, in order from an object side to an image side, a first lens with negative refractive power, a second lens that is a meniscus lens having a convex image-side surface, an aperture stop, a third lens with positive refractive power, and a lens group with positive refractive power. When the center thickness of the first lens is represented as t1, the center thickness of the second lens is represented as t2 and the focal length of the whole system is represented as f, t1/f>1.2 and t2/f>1.2 are satisfied.

Abstract: The projector-type headlamp comprises a projection lens unit and a light source unit. A diffraction grating designed to eliminate chromatic aberrations is provided on at least part of a lens surface of the lens unit. When an x axis in the horizontal direction and a y axis in the vertical direction are defined on a plane perpendicular to the optical axis, R1 is the maximum y coordinate on the lens surface, and 0?A<1, an area of the lens surface in which y<A·R1 comprises a curved surface or a flat surface, at least partially provided with the diffraction grating, and an area of the lens surface in which y?A·R1 comprises a separate curved surface that has a power greater than the power of the curved surface or flat surface, and is not provided with a diffraction grating.

Abstract: An optical lens includes a first lens group with negative refractive power, a second lens group with positive refractive power, and an aperture stop disposed between the first lens group and the second lens group. A total number of lenses in the first lens group is less than three, and a total number of lenses in the second lens group is less than five. The second lens group includes a first lens, a second lens and a third lens arranged in order in a direction away from the aperture stop. Each of the first lens and the second lens is an aspheric lens, and one of the first lens and the second lens has a diffractive optical surface.

Abstract: A microlens array, each microlens containing N sides of a convex polygon and N curved surfaces corresponding to the sides, wherein when the line passing through the microlens vertex and perpendicular to the polygon plane is z axis, the line passing through the intersection point (origin) between z axis and the plane and perpendicular to a side is x axis, z coordinate of the curved surface corresponding to the side is z=f(x), a distance from the origin to the side is t, a virtual curved surface in 0?|x|?t is z=F(x), refractive index of the microlens is no, A and C represents constants, and g ? ( x ) = ? F ? ( x ) ? x = - x ? x ? · Cx 2 + A n 0 ? 1 + ( Cx 2 + A ) 2 - 1 , ? g ? ( x ) - 0.035 ? ? f ? ( x ) ? x ? g ? ( x ) + 0.035 is satisfied and f (x) is determined such that an illuminance distribution in an illuminated area is more uniform than that in the case that the curved surface is shaped in a segment of a circle.

Abstract: An optical imaging system according to the present invention includes, in order from an object side to an image side, a first lens with negative refractive power, a second lens that is a meniscus lens having a convex image-side surface, an aperture stop, a third lens with positive refractive power, and a lens group with positive refractive power. When the center thickness of the first lens is represented as t1, the center thickness of the second lens is represented as t2 and the focal length of the whole system is represented as f, t1/f>1.2 and t2/f>1.2 are satisfied.

Abstract: A projector type headlight can include a projection lens arranged on an optical axis extending in a longitudinal direction of a vehicle, and a light source unit arranged on a more rear side than a back side focal plane of the projection lens, the projection lens including resin lenses which are arranged on the optical axis. A resin lens out of the resin lenses arranged closer to the light source unit includes a diffraction grating provided on a lens face in a side opposite to a light source, the resin lens out of the resin lenses arranged closer to the light source unit has a lens face having a positive power, which is arranged in a light source side, and the diffraction grating is designed so as to cancel chromatic aberration of light emitted from the light source unit and emitted forward through the resin lenses.

Abstract: A projector type headlight can include a projection lens arranged on an optical axis extending in a longitudinal direction of a vehicle, and a light source unit arranged on a more rear side than a back side focal plane of the projection lens, the projection lens including resin lenses which are arranged on the optical axis. A resin lens out of the resin lenses arranged closer to the light source unit includes a diffraction grating provided on a lens face in a side opposite to a light source, the resin lens out of the resin lenses arranged closer to the light source unit has a lens face having a positive power, which is arranged in a light source side, and the diffraction grating is designed so as to cancel chromatic aberration of light emitted from the light source unit and emitted forward through the resin lenses.

Abstract: An imaging optical system includes three reflecting mirrors having first to third reflection surfaces and is configured, such that in an XYZ orthogonal coordinate system using an optical axis at the center of the field of view as Z-axis, the optical axis at the center of the field of view and an optical axis of an image plane are in parallel to each other Assuming that along the path of the beam traveling along the optical axis at the center of the field of view a distance between the second reflection surface and the third reflection surface is L2, a distance between the third reflection surface and the image plane is L3 and fy1 and an equivalent F-number of the imaging optical system is represented as Fno, the relational expression 0.5<Fno(L2/L3)<1.3 is satisfied.

Abstract: To provide a compact image forming optical system in which an incident angle to an imaging plane of a solid-state imaging device is small and whose chromatic aberration, astigmatism, field curvature, and distortion are reduced. An image forming optical system of a first embodiment of the present invention comprises four lenses arranged from the object side to the imaging plane side in order, that are a first lens that is a double-convex lens, a second lens that is a double-concave lens, a third lens that is a positive meniscus lens that is convex toward an image side, and a fourth lens that is a negative meniscus lens that is convex toward an object side. An aperture is placed closer to the object than the image side surface of the first lens.

Abstract: An imaging optical system includes three reflecting mirrors having first to third reflection surfaces and is configured, such that in an XYZ orthogonal coordinate system using an optical axis at the center of the field of view as Z-axis, the optical axis at the center of the field of view and an optical axis of an image plane are in parallel to each other by changing orientation of the optical axis in a YZ section while maintaining the orientation of the optical axis in an XZ section. At least one of the three reflection surfaces is rotationally asymmetric. Assuming that along the path of the beam traveling along the optical axis at the center of the field of view a distance between the second reflection surface and the third reflection surface is L2, a distance between the third reflection surface and the image plane is L3 and fy1 and an equivalent F-number of the imaging optical system is represented as Fno, the relational expression 0.5<Fno(L2/L3)<1.3 is satisfied.

Abstract: To provide a compact image forming optical system in which an incident angle to an imaging plane of a solid-state imaging device is small and whose chromatic aberration, astigmatism, field curvature, and distortion are reduced. An image forming optical system of a first embodiment of the present invention comprises four lenses arranged from the object side to the imaging plane side in order, that are a first lens that is a double-convex lens, a second lens that is a double-concave lens, a third lens that is a positive meniscus lens that is convex toward an image side, and a fourth lens that is a negative meniscus lens that is convex toward an object side. An aperture is placed closer to the object than the image side surface of the first lens.

Abstract: An imaging optical system capable of moving a meridian image plane further closer to an ideal imaging plane vertical to an optical axis with the number of lenses kept constant. At least one plane of at least one optical element and including at least one optical element is divided into at least one zonal area surrounding an optical axis and a center area including the optical axis.

Abstract: An imaging optical system capable of moving a meridian image plane further closer to an ideal imaging plane vertical to an optical axis with the number of lenses kept constant. At least one plane of at least one optical element and including at least one optical element is divided into at least one zonal area surrounding an optical axis and a center area including the optical axis.