Abstract: An image display apparatus including an image display device in which pixels are arranged in a dot-like form and a diffraction grating having a lattice face with a water contact angle of 70.degree. or more. 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.

Abstract: A light diffusing sheet including a clear film (#1) and two light diffusing layers (#2 and #3) formed consecutively thereon. The diffusing sheet is characterized in that the first light diffusing layer (#2) is a film of clear resin incorporated with a light-diffusing material, and the second light diffusing layer (#3) is a film of clear resin having a corrugated surface structure. The first light diffusing layer (#2) has a thickness of 10 .mu.m to 500 .mu.m and the light diffusing material has a weight concentration of less than 3%. The difference in refractive index between the clear resin and light diffusing material is 0.01 .ltoreq. .DELTA.n .ltoreq. 0.12, and the average particle diameter of the light diffusing material is between 4 .mu.m to 30 .mu.m.

Abstract: A two-dimensional diffraction grating (5, 14) has a plurality of grating elements arranged in two directions (X, Y) different from each other. The grating elements in one of the directions (X, Y) have a substantially uniform grating height (h) when viewed in an arbitrarily chosen section along such one of the directions (X, Y) and, also, the grating elements in the other of the directions (X, Y) have a substantially uniform grating height (h) when viewed in an arbitrarily chosen section along the other of the directions (X, Y). An image display device includes an image display unit (4) including a plurality of pixels (10) patterned in a dot matrix in two dimensions and having a path (2) of travel of imagewise rays of light, and the two-dimensional diffraction grating (5) disposed on the path (2) of travel of the imagewise rays of light leading from the image display unit (4).

Abstract: An image display apparatus includes an image display device such as, for example, a liquid crystal display panel, having a plurality of dot-shaped picture elements arranged in a two-dimensional pattern, and a diffraction grating disposed on an optical path through which imagewise rays of light emerging from the device travel. To minimize a reduction in quality and contrast of an image displayed by the device, the member has a spatial cut-off frequency chosen to be of a value lying between the sampling frequency, determined by the pitch between picture elements of the image display device, and the Nyquist frequency. For the same purpose, the intensity of .+-.1st order light relative to the intensity of 0-th order light in the diffraction grating is within the range of 60 to 80% at a center wavelength of the image display device, and the sum of the intensity of the 0-th order light and that of the .+-.

Abstract: To effectively cut off false signals and false color signals which would occur in an imaging device and also to suppress a reduction in quality of images which would result from a generation of a ring-shaped flare, an optical low pass filter comprises a transparent substrate having first and second surfaces opposite to each other. The optical low pass filter is adapted to be disposed between a photo-taking lens and a solid-state imaging element with the first surface confronting the solid-state imaging element. The first surface of the transparent substrate is formed with a diffraction grating. The transparent substrate used in the optical low pass filter is so designed and so structured as to have a thickness (mm) which satisfies the equation, 2.multidot.g.multidot.tan (.theta.1)+2.multidot.t.multidot.tan (.theta.c)<0.9, wherein g represents the distance of spacing between the first surface of the transparent substrate and an image plane of the solid-state imaging element; .theta.

Abstract: An optical low pass filter for use in an imaging device including an objective lens and a solid state image sensor forming a plurality of picture elements thereon, which filter comprises a diffraction grating disposed between the objective lens and the solid state image sensor. The diffraction grating is of a type which the periodicity of an image of the diffraction grating projected onto the solid state image sensor by the objective lens is selected to be twice or 1/n of the periodicity of the picture element, wherein n represents an integer.

Abstract: The present invention provides a process for producing a blazed diffraction grating by using a transmission modulation diffraction grating as a photomask in photolithography. The photomask is composed of a relief modulation diffraction grating (A) made of a transparent material and a blazed diffraction grating (B) made of a material containing a ray absorbing agent. The diffraction grating (A) and the diffraction grating (B) are mated with each other through their grating surfaces.