Abstract: The device comprises an aperture stop disc divided into a plurality of mutually exclusive filtering segments comprising a first, a second and a third filtering segment ; the third filtering segment is adapted to pass a third portion of the spectrum which is included in the portion of the spectrum passing the first and second filtering segments. Due to third filtering segment, the aperture assigned to the color component corresponding to the third portion of the spectrum—preferably blue—is larger than the aperture assigned to the color component corresponding to the portion of the spectrum passing the first and second filtering segments.

Abstract: Method in which a component image associated with a primary color of green hue is processed in a suitable manner to reduce the spatial frequencies corresponding to the transition zones in this component image and in which a plurality of component images including the processed component image are successively displayed. Thanks to the invention, the color break-up defects are noticeably reduced. The invention applies especially to anti-piracy image display methods.

Abstract: To generate a full-color left view, a the cyan(left) component of the anaglyph is added with its red component after being laterally shifted to the left, and, symmetrically, to generate a full-color right view, the red(right) component of the anaglyph is added with its cyan component after being laterally shifted to the right. According to the invention, the shift to the left of the red(right) component is obtained by adding the “details” of the cyan(left) component to a blurred red(right) component, and vice-versa. The “details” of the cyan(left) component is preferably calculated by subtracting a blurred cyan(left) component from the cyan(left) component itself.

Abstract: An illuminating device is described comprising an optical source emitting an unpolarized light beam, a polarizing beam splitter comprising a grid polarizer situated between the faces of two prisms. The light beam penetrates into the first prism through a face and reaches the polarizing beam splitter that transmits the light having a first polarization direction to the face that reflects it toward an exit face. In addition, the splitter reflects the light having a second polarization direction to the face that reflects it toward an exit face.

Abstract: Method to display an image using four or more primaries having different spectral distributions that are distributed into three groups of primaries, wherein, in a visual color space, all primaries belonging to the same group have the same visual color and are metamehc. Each image being got from a combination of three primary images and each primary image being associated with each visual color of a group, the different primaries of each group are spatially or sequentially distributed over the primary image associated with this group, then allowing an efficient anti-copy protection based on metamerization of images, without any supplemental video processing.

Abstract: The invention relates to a projection system for displaying at least one visual image based on three primary colors, comprising a signal processing unit for converting said visual image into at least a visual image based on four primary colors, a frequency band being associated to each color primary, first display means for displaying three first primary colors of said visual image on a screen and second display means for displaying at least the fourth primary color of said visual image on said screen. According to the invention, the system further comprises optical filtering means that are adapted to enhance the separation between the frequency spectrum of the first three primary colors of the first display means and the frequency spectrum of the at least fourth primary color of the second display means. Application to anti-camcorder systems.

Abstract: A method to display images using four or more different primaries having different spectral distributions wherein, in the LMS color space, at least two of these primaries have the same L coordinates and the same M coordinates; thank to the invention, different metamers, when being legally displayed, will be not only perceptually indistinguishable to a viewer with normal color vision but also indistinguishable by most of the viewers with non-normal color vision.

Abstract: Method in which a component image associated with a primary colour of green hue is processed in a suitable manner to reduce the spatial frequencies corresponding to the transition zones in this component image and in which a plurality of component images including the processed component image are successively displayed. Thanks to the invention, the colour break-up defects are noticeably reduced. The invention applies especially to anti-piracy image display methods.

Abstract: A projection module intended to project an image on a screen defining a specified projection plane is disclosed. The module includes an objective, for emitting an imaging beam; a curved mirror; and at least two deflection surfaces for deflecting the imaging beam, the deflection surfaces being placed in the path of the imaging beam between the objective and the curved mirror.

Abstract: A method to display images using four or more different primaries having different spectral distributions wherein, in the LMS color space, at least two of these primaries have the same L coordinates and the same M coordinates; thank to the invention, different metamers, when being legally displayed, will be not only perceptually indistinguishable to a viewer with normal color vision but also indistinguishable by most of the viewers with non-normal color vision.

Abstract: The invention relates to a projection system for displaying at least one visual image based on three primary colours, comprising a signal processing unit for converting said visual image into at least a visual image based on four primary colours, a frequency band being associated to each colour primary, first display means for displaying three first primary colours of said visual image on a screen and second display means for displaying at least the fourth primary colour of said visual image on said screen. According to the invention, the system further comprises optical filtering means that are adapted to enhance the separation between the frequency spectrum of the first three primary colours of the first display means and the frequency spectrum of the at least fourth primary colour of the second display means. Application to anti-camcorder systems.

Abstract: Method to display an image using four or more primaries having different spectral distributions that are distributed into three groups of primaries, wherein, in a visual color space, all primaries belonging to the same group have the same visual color and are metamehc. Each image being got from a combination of three primary images and each primary image being associated with each visual color of a group, the different primaries of each group are spatially or sequentially distributed over the primary image associated with this group, then allowing an efficient anti-copy protection based on metamerization of images, without any supplemental video processing.

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 of displaying images on a projection screen in front of a place for an audience, by using different visually-equivalent metameric colors for different portions of images, and by simultaneously illuminating said place for the audience with perturbing infrared radiations and by simultaneously detecting any image capture device in the place for the audience, wherein: the different metameric colors that are visually-equivalent have different spectral wavelength distributions at least in the red region of wavelengths, detection is performed through the perturbing infrared radiations that are reflected by any object in the place for the audience. Such a system seems impossible to circumvent by pirates using camcorders.

Abstract: The invention relates to an illumination system for combining two light beams. A prism bounded by two entrance faces that form a dihedron. An integrator is coupled to an exit face (20.3) of the prism. Each beam penetrates the prism via one of the entrance faces and is reflected by internal reflection on the other entrance face toward the exit face. These beams are substantially focused onto the entrance face of the integrator in such a way that the latter delivers an almost uniform exit beam. Applications: Projection and backprojection apparatus.

Abstract: The invention relates to a projection objective comprising at least one lens and intended to transmit a divergent light beam onto a flat screen. A hyperbolically shaped mirror is oriented so as to receive, on its convex face, the light emanating from the lens. The invention also relates to a corresponding projection apparatus.

Abstract: The invention relates to a projection system comprising an image source and an objective lens for producing an imaging beam and producing a first image there behind, wherein the first image is off-axis with respect to the imaging beam optical axis. The inventive system comprises a concave mirror which is arranged after the first image on the imaging beam path and produces a second image on a projection plane from the first image.

Abstract: The invention relates to a projection module intended to project an image on a screen defining a specified projection plane. The module comprises: an objective, which itself comprises means for emitting an imaging beam; a curved mirror; and at least two deflection surfaces for deflecting the imaging beam, these surfaces being placed in the path of the imaging beam between the objective and the curved mirror. The invention also relates to an optical motor and to a corresponding projection system.

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: The invention relates to a projection objective comprising at least one lens and intended to transmit a divergent light beam onto a flat screen. A hyperbolically shaped mirror is oriented so as to receive, on its convex face, the light emanating from the lens. The invention also relates to a corresponding projection apparatus.