Patent ID: 8760766
Filing Date: 2014-06-24
Classification: G02B

Abstract:
1. A head-up display apparatus that is configured to project a display image onto a projection surface of a display member, which is installed in a vehicle, to enable a viewer located in a vehicle cabin of the vehicle to view a virtual image of the display image, the head-up display apparatus comprising: a projector that is configured to project a bundle of rays of light, which forms the display image; and a screen member, onto which the bundle of rays of light is projected from the projector, wherein the screen member diffuses the bundle of rays of light, which is projected from the projector, at a predetermined angle of diffusion directly or indirectly toward the display member to guide the bundle of rays of light to both of a main-viewing range and at least one sub-viewing range, which are preset and in each of which the virtual image is visually recognizable by the viewer, wherein: the screen member has a plurality of optical elements, each of which includes a primary curved surface and at least one secondary curved surface; the primary curved surface of each of the plurality of optical elements diffuses the bundle of rays of light toward the main-viewing range through the display member; the at least one secondary curved surface of each of the plurality of optical elements diffuses the bundle of rays of light toward the at least one sub-viewing range through the display member; and a radius of curvature of the primary curved surface of each of the plurality of optical elements is larger than a radius of curvature of the at least one secondary curved surface of the optical element.