Patent ID: 8675283
Filing Date: 2014-03-18
Classification: G02B

Abstract:
1. A head-up display apparatus that is configured to project a display image onto a projection surface of a vehicle and thereby 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 that diffuses the bundle of rays of light such that the bundle of rays of light is guided to a viewing range, in which the virtual image is visually recognizable by the viewer in the vehicle cabin, wherein: the screen member includes a plurality of optical elements; a surface of each of the plurality of optical elements forms a curved surface that diffuses the bundle of rays of light, which enters the curved surface; and the plurality of optical elements is arranged continuously one after another in two or more directions at each corresponding pitch that is set to adjust a peak-to-peak interval of diffracted rays, which are formed in the viewing range by diffraction of the bundles of rays diffused by the plurality of optical elements, to a value that is equal to or smaller than 8 mm.