Image display device

A device for displaying an image consisting of a set of pixels, comprising:

• a substrate provided with an orthogonal reference frame and comprising an upper face,
• an illumination module,
• a common electrode,
• a set of addressing waveguides optically coupled to the illumination module, extending in parallel to an oriented axis xa, parallel to xi,
• a set of addressing electrodes extending in parallel to an oriented axis ya, forming an angle β with the axis yi,
• a matrix of light extraction structures;
• wherein the display device is such that
• the common electrode, the matrix of extraction structures, the set of addressing waveguides and the set of addressing electrodes successively extend from the upper face, in distinct planes parallel to the upper face, and such that
• each extraction structure of the matrix is arranged at an intersection of an addressing waveguide and an addressing electrode, and comprises:
• an intermediate waveguide of a liquid crystal extending in parallel to the upper face from an input face of the intermediate waveguide to an output face of the intermediate waveguide,
• wherein the intermediate waveguide is arranged between the addressing electrode and the common electrode so as to switch a refractive index of the liquid crystal along a direction of polarization, from a first level to a second level strictly greater than the first level, when a variation in an electric potential difference is applied between the addressing electrode and the common electrode, and
• the input face forming an angle γ with the upper face of the substrate greater than or equal to 30 degrees and an angle equal to the angle β with the axis yi:
• a high index region extending from the output face of the intermediate waveguide, to the input face of an adjacent extraction structure of the matrix of extraction structures, the high index region having a refractive index np strictly greater than the first level;
• wherein the display device is configured such that for each extraction structure;
• the first level, the second level, and the arrangement of the intermediate waveguide with respect to the addressing waveguide are such that an optical mode derived from the illumination module and guided in the addressing waveguide, is at least partly coupled by evanescent coupling from the addressing waveguide to the intermediate waveguide, only when the refractive index of the liquid crystal is equal to the second level so as to generate an emitted beam propagating in the high index region from the output face to the input face of the adjacent extraction structure, and
• the angle β is greater than or equal to a strictly positive minimum inclination angle beyond which the emitted beam is reflected by total internal reflection on the input face of the adjacent extraction structure into a reflected beam, to be extracted from the display device into a pixel beam corresponding to the display of a pixel of the image.