Projection optical system, head-up display device, and vehicle
AssigneesMaxell, Ltd., Hitachi Industry & Control Solutions, Ltd.
InventorsMasahiko Yatsu, Koji Hirata, Shigeki Hoshino
Life of this patent
Estimating the term…
Abstract
A compact head-up display device is provided. For that purpose, the head-up display device includes a projection optical system which includes an image forming unit to display image information and an ocular optical system to reflect light emitted from the image forming unit to display a virtual image. In the ocular optical system, a free-form surface lens and a free-form surface concave mirror are arranged in order from the image forming unit. The shape of the free-form surface concave mirror is such that curvature radius RY1 in projection on a vertical cross section of the coordinate system of an eye-box is smaller than curvature radius RX1 in projection on a horizontal cross section.
Claims17
A projection optical system including an ocular optical system to reflect light emitted from an image forming unit for generating image information and project the light on a windshield to display a virtual image,
- wherein the ocular optical system includes a free-form surface lens and a free-form surface concave mirror in order from the image forming unit, and
- if a horizontal direction of an eye-box is defined as X axis, a vertical axis is defined as Y axis, and a direction perpendicular to an XY plane is defined as Z axis,
- when, as for a luminous flux corresponding to a view-point as an arbitrary point in a field of view, a curvature radius (positive value) of a circle determined by three points as projections on a YZ plane of intersections of three light rays passing through two points, an upper and a lower point, and a center point on the Y axis of the eye-box on the free-form surface concave mirror is expressed as RY4 and a curvature radius (positive value) of a circle determined by three points as projections on an XZ plane of intersections of three light rays passing through two points, a left and a right point, and a center point on the X axis of the eye-box on the free-form surface concave mirror is expressed as RX4, RX4>RY4 is satisfied.
A head-up display device comprising:
- an image forming unit to emit light containing image information;
- and
- an ocular optical system to reflect light emitted from the image forming unit and project the light on a windshield to display a virtual image,
- wherein the ocular optical system includes a free-form surface lens and a free-form surface concave mirror in order from the image forming unit, and
- if a horizontal direction of an eye-box is defined as X axis, a vertical axis is defined as Y axis, and a direction perpendicular to an XY plane is defined as Z axis,
- when, among intersections on the free-form surface concave mirror of a luminous flux corresponding to a view-point as an arbitrary point in a field of view, a positive curvature radius of a circle determined by three arbitrary points projected on a YZ plane is expressed as RY1 and a positive curvature radius of a circle determined by three arbitrary points projected on an XZ plane is expressed as RX1, RX1>RY1 is satisfied.
Dependencies are inferred from the claim text.