Head-up display system

An independent optical unit for head-up display system for motor vehicle configured to display in a field of view of a driver a final virtual image arising from an object image originating from a projector, said unit comprising:

• a first optical component configured to reflect an incident light ray emanating from the projector towards the field of view of the driver;
• a second optical component placed in the field of view of the driver and intersecting with the light ray reflected by the first optical component for the positioning of the final virtual image;
• and,
• an adjustment means configured to facilitate adjustment of a second position of the second optical element relative to a first position of the first optical element, wherein
• the first optical component is configured to enlarge the object image and increase a depth of field of the object image, and
• the second optical component is configured to orient the final virtual image in a vertical plane in the field of view, the second optical component being made of a transparent material characterized as having a lenticular shape of which the face on the side of the second optical component toward the driver is flat and includes a diffraction grating for positioning the final virtual image, said diffraction grating comprising at least one set of straight lines that are parallel and equidistant having a pitch between 0.4 micrometers (μm) and 1 μm, a ratio of a width of the line over the pitch between 0.3 and 0.6, such that the final virtual image is positioned in the vertical plane without producing for the driver a deformation of the exterior scene visible through the second optical component, the said lenticular shape and the diffraction grating being designed to not deform the exterior scene visible to the driver through the second optical component.