North American Philips Corporation

North American Philips Consumer Electronics Corp.

U.S. Philips Corporation

Philips Electronics North America Corporation

Nap Consumer Electronics Corp.

Ralph H Bradley, Jr

William F Guerinot

Jill F Goldenberg

Thomas S McKechnie

Peter J Janssen

Jeffrey Arthur Shimizu

Joseph P Bingham

Detlev Otto

Joshua D Eskin

Stephen T Troemel

Eugene Lubchenko

Leendert Vriens

Johan Andrea

A color projection video system utilizing only a single light valve. A white light source is separated into into red, green and blue bands. Scanning optics cause the RGB bands to be sequentially scanned across a light valve, such as a transmission LCD panel. Prior to each color passing over a given row of panels on the light valve, that row will be addressed, by the display electronics with the appropriate color content of that portion of the image which is being displayed. The image is projected by a projection lens onto a viewing surface, such as a screen. The sequence of light bands occurs so quickly as to give the viewer an appearance of simultaneous full color.

Single panel color projection video display

A video color image projector which includes a block of crossed dichroic mirrors for combining the light rays from image rasters on respective monochrome image display devices and a projection lens for projecting the composite color rays so as to form an enlarged color image on a display screen. Each display device has a faceplace which is convex on the interior surface thereof and having thereon an interference filter in the form of an internal angularly reflecting coating (IARC). Each faceplate is liquid - coupled to a negative power lens element, so that the faceplate, coupling liquid (or gel) and such lens element effectively constitute a single negative power field flattener lens at each entrance side of the dichroic block. The composite color rays at the exit side of the dichroic block are projected on the display screen by an assembly of lens elements which includes at least one optically positive lens element. The focal length of the complete projection lens formed by such assembly and each of the negative field flattener lenses may be from 0.5 to 0.9 times the diagonal D of the image raster on each display device, so that the projector is sufficiently compact to be included in a cabinet suitable for consumer television receivers.

Short focal length video color projector employing dichroic mirror block

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

A rear projection screen for color television of the type having an array of vertically oriented, parallel lenticular elements on the front surface, uses two diagonally crossed, parallel lenticular element arrays embedded in the screen to control spreading of light into the front lenticular array, achieving better control and less attenuation of the light than systems using surface of bulk diffusion or a single horizontal lenticular array.

Rear projection screen

A front projection screen has lenticules separated by grooves. A black plastic structure having protruding black ribs is aligned with the lenticules so that the ribs protrude into the grooves with clearance on both sides. For a front projection screen the base from which the ribs protrude is shaped to conform to the shape of the tips of the lenticules and is light absorbent. Preferably, the structure is a molded plastic manufactured by the same tooling and replication techniques which produce the lenticular array.

Lenticular arrays for front projection screens and contrast improving

A wide screen television monitor capable of displaying standard width picture in which uneven 'Coulomb aging' is minimized. The television monitor includes circuitry for causing the standard width picture to cyclically traverse the width of the display screen of the television monitor in accordance with a prescribed function. The period of repetition of this movement is of such a duration that a casual observer of the television monitor is unaware of the movement of the picture.

Dual aspect ratio display with cyclicly moving raster area to prevent

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

LCD color television front projection screen has a rear vertically oriented lenticular lens array, the sidewalls of the lenticules steeply inclined to achieve total internal reflection of rays from a projected image into tip regions of the lenticules, an external reflective surface behind the array for reflecting the projected rays back into an audience field in front of the screen, and black masking between the lenticules for absorbing ambient rays.

Front projection screen with rear light concentrating lens array

Color television rear projection screen having a front vertically oriented lenticular lens array, a circular Fresnel lens component with an infinite second conjugate, and a horizontally oriented linear Fresnel lens component with a finite second conjugate, the screen having improved luminance uniformity.

Rear projection screen with improved luminance uniformity

In a color picture projection system three monochrome pictures are superimposed to form a color display on a projection screen by means of a chromatic projection lens system in each of three channels. Each channel has a reflector to fold the light path. Since at least one monochrome picture (e.g. the blue picture) includes radiation within a desired band of wavelengths corresponding to its associated color and radiation outside of this desired band, the reflector in this channel is wavelength-selective and reflects only the radiation within the desired band towards the projection screen. The undesired radiation is transmitted through the reflector so that it does not reach the projection screen. Achromatic lenses are therefore not required.

Color picture projection system with a wavelength-selective reflector

A rear projection screen is disclosed which uses a front surface lenticular array to distribute light from projection light sources through a horizontal angle of virtually 180.degree. with uniform luminance. Each lenticular element of the array is characterized by having a height to width ratio of at least 3:2 and a pitch width to tip width ratio of at least 2:1. The lenticular array is further characterized as having the capability of having up to two-thirds of the front surface area black masked. When used in a color television system, the rear projection screen exhibits minimal color shift.

Growing community of inventors

Kingsport, TN, United States of America

Ralph H Bradley, Jr