Head-up display system

A head-up display system that displays a virtual image so as to be superimposed on a real view visually recognizable through a light-transmitting member, the head-up display system comprising:

• a display that emits a light flux visually recognized by an observer as the virtual image;
• and
• a light guide body that is disposed apart from the light-transmitting member and projects the light flux to the light-transmitting member,
• wherein the light guide body includes an incident surface on which the light flux from the display is incident, a coupling region that changes a traveling direction of the light flux incident on the incident surface, a first expansion region that expands a visual recognition region by replicating the light flux propagated from the coupling region into a plurality of light fluxes in a first direction, a second expansion region that expands the visual recognition region by replicating the light fluxes replicated in the first expansion region in a second direction intersecting the first direction, and an emission surface from which the light fluxes replicated in the second expansion region are emitted,
• wherein a light beam at a center of the light flux emitted from the display is incident while being inclined with respect to a normal direction of the incident surface of the light guide body,
• wherein, when a direction in which the observer visually recognizes the virtual image from the visual recognition region of the virtual image is a Z-axis, a horizontal direction orthogonal to the Z-axis is an X-axis, and a direction orthogonal to an XZ plane formed by the X-axis and the Z-axis is a Y-axis, in the light guide body, the light flux incident on the coupling region and changed in the traveling direction propagates to the first expansion region, is replicated in the first direction that is the horizontal direction, and propagates to the second expansion region, and is replicated in the second direction in the second expansion region and is emitted from the emission surface,
• wherein the light guide body is inclined with respect to the Z-axis in a cross-sectional view of a YZ plane formed by the Y-axis and the Z-axis, and
• wherein the light guide body is disposed so as to be inclined with respect to the light-transmitting member in a cross-sectional view of the YZ plane, and a light beam at a center of the light fluxes emitted from the light guide body is emitted toward the light-transmitting member at an angle inclined toward the visual recognition region relative to an axis perpendicular to the emission surface of the light guide body in a cross-sectional view of the YZ plane.