Patent ID: 6067137
Filing Date: 2000-05-23
Classification: G02F

Abstract:
An image display apparatus comprising:an image display device in which pixels are arranged;a diffraction grating having a lattice face;wherein the angle of contact of water at the lattice face in the diffraction grating is 70.degree. or more;wherein the diffraction grating is arranged on a display optical path of the image display device such that the lattice face of the diffraction grating faces toward a side of a viewer and a viewing angle of the image display device is enlarged by the diffraction grating;wherein the diffraction grating satisfies the following Equation (1):L/12<T.multidot.D.multidot.(n-1)/P<4.multidot.L (1)where T is given by the following Equation (2): ##EQU3## where a period of a lattice of the diffraction grating comprising a base portion and a lattice portion is represented by P, a period of the pixels of the image display device is represented by L, a stepwise difference between a recessed portion and a projected portion in the lattice portion of the diffraction grating is represented by D, an index of diffraction of the lattice portion of the diffracting grating is represented by n, a number of layers of from faces of the pixels of the image display device on the viewer's side to the base portion of the diffraction grating is represented by M, an index of diffraction of each of the layers of the faces of the pixels of the image display device on the viewer's side to the base portion of the diffraction grating is represented by ni, and a thickness of each of the layers is represented by ti, respectively.