Abstract: A system includes a transparent rod, a light guide assembly, and first and second transparent monolithic optical parts (TMOPs) having the same refractive index. The first TMOP has a first surface having two prism arrays separated by a flat surface having a partially reflective coating, and an opposite second flat surface. Each prism array has two prisms having first and second surfaces oblique to each other. The prism arrays' first surfaces have a partially reflective coating contrary to the second surfaces. The second TMOP has a surface having a geometrically complementary shape relative to the first TMOP first surface's shape and has an opposite second flat surface. When assembled using a first optically transparent adhesive, the first and second TMOPs' second surfaces are parallel. The rod has a partially reflective gradient coating on one surface where it's assembled with the light guide assembly using a second optically transparent adhesive.

Abstract: An optical guide including a first piece made from a transparent material, the first piece including on the surface an array of extraction microstructures composed of a succession of extraction microstructures arranged for projecting to a finite distance an image injected into the optical guide. Each extraction microstructure has a prismatic shape with two faces, one face being called an active surface and having a semi-reflective coating for extracting the image from the optical guide and the other face being called a passive surface and not having any semi-reflective coating. Each active surface is spherical and has an inclination smaller by a mean angle than any active surface immediately preceding in the succession of microstructures in the direction of propagation of the image in the optical guide.

Abstract: A light guide includes a first and second transparent monolithic optical parts (TMOP). The first TMOP has a first surface having two sets with one flat surface followed by one prism array. Each flat surface has a partially-reflective coating, and the first TMOP has a flat opposite second surface. Each prism array has two prisms having a first and a second surfaces which are oblique to each other and to the first TMOP's opposite second surface. The prism arrays first surfaces have a partially-reflective coating. The second TMOP has a first surface with a geometrically complementary shape relative to the shape of the first TMOP's first surface, and has a flat opposite second surface. The first and second TMOPs are assembled together using an optically transparent adhesive material, such that the second surfaces of the first and second TMOP of the light guide assembly are parallel to each other.

Abstract: An optical device includes an optical guide adapted for propagating a light beam by successive total internal reflections and an injection device adapted for injecting the light beam into the optical guide via an injection section. A polarizing material is present between the optical guide and the injection device at the injection section. The injection device includes a prism and an assembly formed by a quarter-wave plate and curved mirror, the injection device being arranged so that a light beam reflected by the polarizing material in the direction of the curved mirror passes through the quarter-wave plate and is then reflected by the curved mirror in the direction of the polarizing material and passes through the quarter-wave plate again.

Abstract: An optical guide comprises at least one guiding element adapted for enabling, by total internal reflections, transporting an image taking the form of a collimated light beam from an injection zone to an extraction zone where an extracting device for extracting the image is mounted. The optical guide comprises a retardation plate and a polarization beam splitter, the polarization beam splitter being placed between the guiding element and the extracting device. The optical guide is such that each ray of said collimated light beam striking the polarization beam splitter for the first time separates into two portions, a first portion being transmitted to the extracting device so as to define a first light imprint and a second portion being reflected by the polarization beam splitter, said second portion continuing to be guided by the guiding element and thus passing twice through the retardation plate before striking the polarization beam splitter so as to define a second light imprint.

Abstract: An optical guide comprises at least one guiding element adapted for enabling, by total internal reflections, transporting an image taking the form of a collimated light beam from an injection zone to an extraction zone where an extracting device for extracting the image is mounted. The optical guide comprises a retardation plate and a polarisation beam splitter, the polarisation beam splitter being placed between the guiding element and the extracting device. The optical guide is such that each ray of said collimated light beam striking the polarisation beam splitter for the first time separates into two portions, a first portion being transmitted to the extracting device so as to define a first light imprint and a second portion being reflected by the polarisation beam splitter, said second portion continuing to be guided by the guiding element and thus passing twice through the retardation plate before striking the polarisation beam splitter so as to define a second light imprint.

Abstract: An optical guide comprises an injection zone intended to inject into the optical guide a light signal and an extraction zone intended to provide the light signal after transport by the optical guide. The optical guide comprises, in a superposed manner, at least two guidance elements. In a zone situated between the injection zone and the extraction zone, the guidance elements are partially separated from one another by a semi-reflective coating of length, in the direction or propagation of the light signal in the optical guide, dependent on a minimum angle of incidence of the light signal and on the thickness of at least one of the guidance elements that the semi-reflective coating separates.

Abstract: An optical device includes an optical guide adapted for propagating a light beam by successive total internal reflections and an injection device adapted for injecting the light beam into the optical guide via an injection section. A polarising material is present between the optical guide and the injection device at the injection section. The injection device includes a prism and an assembly formed by a quarter-wave plate and curved mirror, the injection device being arranged so that a light beam reflected by the polarising material in the direction of the curved mirror passes through the quarter-wave plate and is then reflected by the curved mirror in the direction of the polarising material and passes through the quarter-wave plate again.

Abstract: The invention proposes a short-distance front projection system, that is to say with a wide angle, occupying a small volume and offering a possibility of focusing as well a zoom function. It makes it possible to obtain images with a diagonal greater than 2 meters, the whole of the optical system being at least 50 cm from the plane of the image. This projector is constructed on the basis of three optical elements: an ocular, an afocal lens system and a final group forming an objective intended to form the intermediate image in front of the mirror.

Abstract: An optical guide comprises an injection zone intended to inject into the optical guide a light signal and an extraction zone intended to provide the light signal after transport by the optical guide. The optical guide comprises, in a superposed manner, at least two guidance elements. In a zone situated between the injection zone and the extraction zone, the guidance elements are partially separated from one another by a semi-reflective coating of length, in the direction or propagation of the light signal in the optical guide, dependent on a minimum angle of incidence of the light signal and on the thickness of at least one of the guidance elements that the semi-reflective coating separates.

Abstract: The invention proposes a short-distance front projection system, that is to say with a wide angle, occupying a small volume and offering a possibility of focusing as well a zoom function. It makes it possible to obtain images with a diagonal greater than 2 metres, the whole of the optical system being at least 50 cm from the plane of the image. This projector is constructed on the basis of three optical elements: an ocular, an afocal lens system and a final group forming an objective intended to form the intermediate image in front of the mirror.

Abstract: The invention relates to informative eyeglasses (500) comprising: —an optical guide (514) forming an eyeglass lens (500) and exhibiting an injection section (504) and an extraction section (508), —a catadioptric collimator (150) comprising: —a refractive entrance surface (202), a first reflecting surface (204), a second reflecting surface (206) and a refractive exit surface (208), each surface (202, 204, 206, 208) constituting a surface of revolution with the same axis of revolution, said axis of revolution constituting the optical axis (102) of the collimator (150), —an illumination source (104) generating an incident light beam (108) illuminating the refractive entrance surface (202), and the axis of which is shifted with respect to said optical axis (102) and which is substantially in the focal plane of said catadioptric collimator (150).

Abstract: A method for illuminating the surface of an object by using a source beam is provided. The source beam is partitioned into as many illumination sub-beams as there are surface elements to be illuminated, and their aperture is modulated as a function of the predetermined luminous intensity to be assigned to the surface element. Each surface element is illuminated with the aid of one of said illumination sub-beams. Used for illuminating the imagers of projection devices, this method makes it possible to add a second modulation stage allowing the display contrast of the images to be improved.

Abstract: The invention is directed at least in part to a method of illuminating an imager for projecting images, implementing light-emitting diodes of different colors, the diodes being designed to provide a beam illuminating the imager. According to various embodiments of the invention, for a set of at least one imager, the method includes receiving each image of the set; determining a color base dependent on the set of at least one image, called a secondary color base; and dynamically controlling the diodes according to the secondary color base. The invention also relates to a system implementing the method and a projector comprising such a system.

Abstract: A display device comprises revolving coloured wheels, so as to generate a periodic coloured beam, and an imager which modulates the coloured beam as a function of a received video signal. The coloured beam (8) takes successively at each period a plurality of primary colours in synchronism with the images generated by the imager for each primary colour. By adjustment of the relative position of the coloured wheels, it is possible to modify the hue of the primary colours so as to best match them to the received video signal.

Abstract: The invention relates to informative eyeglasses (500) comprising:—an optical guide (514) forming an eyeglass lens (500) and exhibiting an injection section (504) and an extraction section (508),—a catadioptric collimator (150) comprising:—a refractive entrance surface (202), a first reflecting surface (204), a second reflecting surface (206) and a refractive exit surface (208), each surface (202, 204, 206, 208) constituting a surface of revolution with the same axis of revolution, said axis of revolution constituting the optical axis (102) of the collimator (150),—an illumination source (104) generating an incident light beam (108) illuminating the refractive entrance surface (202), and the axis of which is shifted with respect to said optical axis (102) and which is substantially in the focal plane of said catadioptric collimator (150).

Abstract: Optical system for a projector, comprising: at least a first polarizing beam splitter for splitting a source illumination beam into a first illumination beam linearly polarized along a first direction and a second illumination beam polarized perpendicular to the first direction; at least one color wheel intersecting the polarized illumination beams in two different regions and producing a first color beam linearly polarized along the first direction and a perpendicularly polarized second color beam; and two imagers illuminated by the first and second polarized color beams respectively.

Abstract: The invention relates to a projection system comprising: a polychromatic light source and at least one imaging assembly illuminated by an associated polychromatic illumination beam, and comprising: two separate colored wheels, respectively called first and second colored wheel; and three separate imagers, respectively called first, second and third imagers. At least one part of the polychromatic beam, called first source beam, illuminating the first colored wheel which separates said source beam into a first monochromatic beam and into a two-tone beam, said first monochromatic beam illuminating the first imager and said two-tone beam being transmitted toward the second colored wheel. The second colored wheel being illuminated by said two-tone beam and separating said two-tone beam into second and third monochromatic beams, respectively illuminating said second and third imagers respectively.

Abstract: The invention relates to a backlighting system for a liquid-crystal display screen, comprising: an illumination source producing an illumination beam; an objective illuminated by said illumination beam; at least one folding mirror illuminated by the illumination beam coming from the objective; and a Fresnel lens capable of collimating and redirecting the illumination beam reflected by said at least one folding mirror, the beam transmitted by the Fresnel lens being intended to back-light said display screen.

Abstract: Method for illuminating the surface of an object by using a source beam, in which: said source beam is partitioned into as many illumination sub-beams as there are surface elements to be illuminated, their aperture being modulated as a function of the predetermined luminous intensity to be assigned to said surface element, each surface element is illuminated with the aid of one of said illumination sub-beams. Used for illuminating the imagers of projection devices, this method makes it possible to add a second modulation stage allowing the display contrast of the images to be improved.