North American Philips Corporation

U.S. Philips Corporation

Thomas S McKechnie

Jill F Goldenberg

William F Guerinot

Ralph H Bradley, Jr

Jeffrey Arthur Shimizu

Joshua D Eskin

The present invention is directed to illumination structures useful in display systems for projection video and television devices performing with high efficiency and good color rendition. Such illumination sources include a light source having an inner and outer envelope with plane mirrors within the outer envelope to direct reflected light, a light source providing randomly polarized light with polarizing structure for passing a desired polarization of the polarized light, and an arc lamp having at least two arcs for supplying uniform illumination in two dimensions. These illuminating structures enable significantly improved illumination in the appropriate projection video and television systems.

Illumination system for LCD projection television

Display systems useful for projection video and television systems are provided to perform with high efficiency and good color rendition. In these systems, color may be provided, as one example, by various light valves, such as liquid crystal displays. Each of the liquid crystal displays are positioned at equal path distances from an illuminating subsystem, and have equal path distances from the light valves to a projection subsystem. This enables optimum illumination of each of the light valves. Various embodiments of arranging the light valves, as well as providing illumination are described.

Display system with equal path lengths

A one-piece projection screen with improved overall efficiency and contrast, the elimination of corner illumination deficiencies and undesirable image artifacts. The optical power of the screen is divided between two or more surfaces acting as Fresnel lenses, and the region or medium separating the surfaces has a different index of refraction than that of the mediums upstream or downstream of the surfaces. The preferred embodiment of the projection screen includes a diffuser and a lenticular array downstream of the surfaces.

One-piece projection screen

A screen consists of a clear mechanically stable substrate and a bulk diffuser portion which is as close to the front lenticules as possible. The diffuser may be dispersed within the lenticules or in a separate area immediately adjacent to them. The screen may be a two element screen, either the front or the rear element having the clear substrate. Surface diffusion may be used as an alternative, or in addition to, the bulk diffuser.

Projection screen having high resolution and good mechanical stability

A bulk diffuser for rear projection television screens which exhibits a Gaussian intensity profile. By appropriately selecting the indices of refraction of the substrate and the spheres therein and the range of diameters of the spheres, the intensity half-angle is made equal to the energy half-angle.

Bulk diffuser for a projection television screen

A projection television system includes a planar projection screen, a CRT for producing a phosphor image, and a lens assembly for focusing the phosphor image onto the projection screen. The lens assembly is arranged such that its optical axis is skewed with respect to an axis normal to the projection screen. The system further includes a correction member on which the CRT and the lens assembly are fixed so that a planar outside surface of the CRT is oriented at the Scheimpflug angle with respect to a flat rear optical surface of the lens assembly. In a preferred embodiment, the correction member is integral with rear element of the lens assembly.

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Ossining, NY, United States of America

Thomas S McKechnie