Patent ID: 9395541
Filing Date: 2016-07-19
CPC Classification: G02B

Claim Text:
1. A head-up display apparatus for displaying a virtual image of a display image by projecting the display image to a projection plane in an interior of a vehicle, the head-up display apparatus comprising: a projector projecting a light beam; and a screen including a plurality of optical elements that are arranged in a grid pattern on an outside surface of the screen, the screen diffusing the light beam projected from the projector toward the projection plane, wherein each of the plurality of optical elements has a curved surface having a convex or a concave shape, the light beam being diffused through the curved surface, one of the plurality of optical elements has a thickness at a curvature center point of the curved surface that is different from that of an other of the plurality of optical elements that is immediately adjacent to the one of the plurality of optical elements, the outside surface includes a receiving surface into which the light beam enters and an emitting surface from which the light beam is emitted, the curved surface is formed on at least one of the receiving surface and the emitting surface, m is defined as an odd numerical value greater than or equal to 1, λ is defined as a wavelength of the light beam, n is defined as a refractive index of the plurality of optical elements, a difference between the thickness of the one of the plurality of optical elements and the thickness of the other of the plurality of optical elements is defined as ΔT, and