Abstract: A zoom lens consists of, in order from an object side, a negative first lens group, a positive second lens group, a positive third lens group, a negative fourth lens group, and a positive fifth lens group. The first lens group consists of, in order from the object side, a first A lens group that does not move during focusing, a first B lens group that moves during focusing, and a first C lens group that does not move during focusing. During zooming, the first lens group and the fifth lens group do not move, and the second lens group, the third lens group, and the fourth lens group move. The fourth lens group includes a stop. The zoom lens satisfies a predetermined conditional expression.

Abstract: The zoom lens consists of a first lens group, a front group, a middle group, and a rear group, in order from an object side. The first lens group has a positive refractive power and includes a negative lens and a positive lens, successively in order from a position closest to the object side to an image side. The front group consists of one or more lens groups that move during zooming and has a negative refractive power as a whole throughout an entire zoom range. The middle group includes only one lens group as a lens group. The rear group consists of a plurality of lens groups. An aperture stop is disposed between a lens surface closest to the image side in the front group and a lens surface closest to the object side in the rear group. The zoom lens satisfies predetermined conditional expressions.

Abstract: A zoom lens consists of, in order from the object side, a first lens group that has a positive refractive power, a middle group that includes a plurality of lens groups in which the spacings between adjacent lens groups change during zooming, and the final lens group. The focusing group that moves during focusing is disposed in the middle group. The zoom lens satisfies predetermined conditional expressions.

Abstract: The zoom lens consists of, in order from the object side, a first lens group that has a positive refractive power, a second lens group that has a positive refractive power, and a subsequent group. During zooming, a spacing between the first lens group and the second lens group changes, and a spacing between the second lens group and the subsequent group changes. The subsequent groups include a focusing group that moves during focusing.

Abstract: The zoom lens consists of, in order from an object side, a positive first lens group, a negative second lens group, a third lens group, a positive fourth lens group, and a positive fifth lens group. During zooming, the second lens group, the third lens group, and the fourth lens group move. The first lens group consists of, in order from an object side, a negative first a lens group, a positive first b lens group that moves during focusing, and a positive first c lens group. A most-image-side lens of the first b lens group is a negative meniscus lens having a convex surface facing an object side.

Abstract: The zoom lens consists of, in order from an object side, a positive first lens group, a negative second lens group, a positive third lens group, a positive fourth lens group, and a positive fifth lens group. During zooming, the second lens group, the third lens group, and the fourth lens group move. The first lens group consists of, in order from an object side, a negative first a lens group, a positive first b lens group that moves during focusing, and a positive first c lens group. The second lens group includes one positive lens and one or more negative lenses successively in order from a most object side to an image side.

Abstract: A zoom lens consists of, in order from an object side, a negative first lens group, a positive second lens group, a positive third lens group, a negative fourth lens group, and a positive fifth lens group. The first lens group consists of, in order from the object side, a first A lens group that does not move during focusing, a first B lens group that moves during focusing, and a first C lens group that does not move during focusing. During zooming, the first lens group and the fifth lens group do not move, and the second lens group, the third lens group, and the fourth lens group move. The fourth lens group includes a stop. The zoom lens satisfies a predetermined conditional expression.

Abstract: There is provided a head-up display device which has a small size and of which the aberration is small and the range of an eye box in a vertical direction is wide. The head-up display device 10 includes a first optical system that includes at least one concave mirror arranged along an optical path of display light in order from an image display surface 1, and a second optical system that includes at least one concave mirror arranged along the optical path of the display light in order from the image display surface 1 side. An intermediate image is formed between the first and second optical systems on the optical path, and the first optical system includes a double reflection mirror that reflects the display light twice on the optical path.

Abstract: The zoom lens consists of, in order from an object side, a positive first lens group, a negative second lens group, a positive third lens group, a positive fourth lens group, and a positive fifth lens group. During zooming, the second lens group, the third lens group, and the fourth lens group move. The first lens group consists of, in order from an object side, a negative first a lens group, a positive first b lens group that moves during focusing, and a positive first c lens group. The second lens group includes one positive lens and one or more negative lenses successively in order from a most object side to an image side.

Abstract: The zoom lens consists of, in order from an object side, a positive first lens group, a negative second lens group, a third lens group, a positive fourth lens group, and a positive fifth lens group. During zooming, the second lens group, the third lens group, and the fourth lens group move. The first lens group consists of, in order from an object side, a negative first a lens group, a positive first b lens group that moves during focusing, and a positive first c lens group. A most-image-side lens of the first b lens group is a negative meniscus lens having a convex surface facing an object side.

Abstract: There is provided a head-up display device which has a small size and of which the aberration is small and the range of an eye box in a vertical direction is wide. The head-up display device 10 includes a first optical system that includes at least one concave mirror arranged along an optical path of display light in order from an image display surface 1, and a second optical system that includes at least one concave mirror arranged along the optical path of the display light in order from the image display surface 1 side. An intermediate image is formed between the first and second optical systems on the optical path, and the first optical system includes a double reflection mirror that reflects the display light twice on the optical path.

Abstract: An optical filter having spectral properties that reflects light of a first wavelength band and transmits light of a second wavelength band that does not include the first wavelength band is provided between a greater distance optical system that displays a virtual image at a greater distance from an image reflection surface and a closer distance optical system that displays a virtual image at a closer distance from the image reflection surface. The optical filter aligns the optical paths of display light of the greater distance optical system and the closer distance optical system and guides the display light to the image reflection surface. Further, the powers of the greater distance optical system and the closer distance optical system are set to be different.

Abstract: A head-up display device includes a first mirror having power, a second mirror having power, and a light-blocking member that is provided with an aperture. An image reflective surface has a convergence action. Display light emitted from an image display surface is reflected by the first mirror and the second mirror in this order, passes through the aperture, and reaches the image reflective surface. The image display surface is disposed on the same side as an observer and on a side opposite to the first mirror with respect to luminous flux that travels toward the aperture from the second mirror. The first mirror is a concave mirror. The shape of the cross-section of the second mirror taken along a front-rear direction is a convex shape.

Abstract: A head-up display device includes optical path deflecting means, a first mirror having power, a second mirror having power, and a light-blocking member that is provided with an aperture. Display light emitted from an image display surface is reflected by the optical path deflecting means, the first mirror, and the second mirror in this order, passes through the aperture, and reaches an image reflective surface. The image display surface and the optical path deflecting means are disposed on the same side as an observer and on a side opposite to the first mirror with respect to luminous flux that travels toward the aperture from the second mirror, and the image display surface is disposed on a side opposite to the second mirror with respect to luminous flux that travels toward the first mirror from the optical path deflecting means.

Abstract: A head-up display device includes a first mirror having power, a second mirror having power, and a light-blocking member that is provided with an aperture. An image reflective surface has a convergence action. Display light emitted from an image display surface is reflected by the first mirror and the second mirror in this order, passes through the aperture, and reaches the image reflective surface. The image display surface is disposed on the same side as an observer and on a side opposite to the first mirror with respect to luminous flux that travels toward the aperture from the second mirror. The first mirror is a concave mirror. The shape of the cross-section of the second mirror taken along a front-rear direction is a convex shape.

Abstract: A head up display apparatus includes: a first mirror having power; a second mirror having power; and a light shielding member provided with an aperture. The aperture is provided between an image display surface and the second mirror. Display light which is output from the image display surface is reflected by the first mirror, the second mirror, and the first mirror in this order, and reaches a front windshield (image reflection surface) by passing through the aperture.

Abstract: A projection lens includes a compound aspherical lens in which a resin layer is formed on a surface of a glass lens and a lens surface of the resin layer on the air contacting surface side has an aspherical shape. If the glass transition temperature of the resin layer is taken as Tg and its unit is taken as ° C., Tg of at least one of the resin layers is 150<Tg<280. The projection lens is configured to satisfy a given conditional expression with respect to the at least one of the resin layers.

Abstract: A head up display apparatus includes: a first mirror having power; a second mirror having power; and a light shielding member provided with an aperture. The aperture is provided between an image display surface and the second mirror. Display light which is output from the image display surface is reflected by the first mirror, the second mirror, and the first mirror in this order, and reaches a front windshield (image reflection surface) by passing through the aperture.

Abstract: An optical filter having spectral properties that reflects light of a first wavelength band and transmits light of a second wavelength band that does not include the first wavelength band is provided between a greater distance optical system that displays a virtual image at a greater distance from an image reflection surface and a closer distance optical system that displays a virtual image at a closer distance from the image reflection surface. The optical filter aligns the optical paths of display light of the greater distance optical system and the closer distance optical system and guides the display light to the image reflection surface. Further, the powers of the greater distance optical system and the closer distance optical system are set to be different.

Abstract: A projection zoom lens constituted by: a negative first lens group; a positive final lens group; and moving lens groups between the first and the final lens groups that move independently while changing magnification, satisfies the conditional formulae below: 1.00<(Rf2?Rr2)/(Rf2+Rr2)??(1) 0.00?(Rr2?Rf3)/(Rr2+Rf3)<0.15??(2) 2.5<Bf/Im???(9) wherein Rf2 and Rr2 respectively are the radii of curvature of the front and rear surfaces of the second lens from the magnification side within the most reduction side moving lens group, Rf3 is the radius of curvature of the front surface of the third lens from the magnification side within the most reduction side moving lens group, Bf is the back focus of the entire system at the reduction side at the wide angle end as an air converted length, and Im? is the maximum effective image circle diameter at the reduction side.