Head up display device that utilizes a backlight toroidal mirror to adjust an eye box

A head up display device that utilizes a backlight Toroidal mirror to adjust an eye box, suitable for use with an imaging semi-reflector and comprising:

• a backlight source for projecting a backlight beam;
• the backlight Toroidal mirror being rotatable and including an X-axis curvature in an axis X and a Y-axis curvature in an axis Y, wherein the X-axis curvature is different from the Y-axis curvature, and the backlight Toroidal mirror is used to reflect the backlight beam of the backlight source;
• a display panel configured to display an image and the backlight beam from the backlight Toroidal mirror passing through the display panel to form an image beam;
• and
• an imaging concave mirror configured to reflect the image beam to the imaging semi-reflector to form a display panel virtual image on a side of the imaging semi-reflector away from a viewer, and a backlight real image which is on another side of the imaging semi-reflector close to the viewer and in the viewer's eyes, wherein the backlight real image is the eye box;
• wherein there is an off axis optical path between the backlight source and the backlight Toroidal mirror, the backlight source is reflected and focused on an X-axis backlight focusing plane by the X-axis curvature, the backlight source is reflected and focused on a Y-axis backlight focusing plane by the Y-axis curvature, a range of the eye box is from the X-axis backlight focusing plane to the Y-axis backlight focusing plane, a rotation of the backlight Toroidal mirror elongates or shortens the range of the eye box on an imaging optical path of the backlight real image, so that the viewer's eyes remain within the eye box while moving along the imaging optical path of the backlight real image.