Light guide plate unit and image display device

An image display device, comprising:

• a light guide plate unit, including:
• a light guide plate;
• a first diffraction grating provided on a first surface of the light guide plate;
• a second diffraction grating on the first surface side of the light guide plate;
• and
• a transition zone structure on the first surface side of the light guide plate, wherein the transition zone structure extends from a first end point at or adjacent to the first diffraction grating to a vertex point, and from the vertex point to a second end point at or adjacent to the second diffraction grating, and wherein the first and second end points are closer to the first surface of the light guide plate than the vertex.

A light guide plate unit, comprising:

• a light guide plate;
• a first diffraction grating disposed on a first surface side of the light guide plate;
• a second diffraction grating on the first surface side of the light guide plate;
• a transition zone structure on the first surface side of the light guide plate, wherein a part of the transition zone structure is between the first diffraction grating and the second diffraction grating;
• and
• a coating layer on at least portions of a side of the transition zone structure opposite a side of the transition zone structure adjacent the first surface side of the light guide plate.

A light guide plate unit, comprising:

• a light guide plate;
• a first diffraction grating disposed on a first surface side of the light guide plate;
• a second diffraction grating on the first surface side of the light guide plate;
• a transition zone structure above the first surface side of the light guide plate, wherein a part of the transition zone structure is between the first diffraction grating and the second diffraction grating;
• and
• a reflective coating layer on the first surface side of the light guide plate, wherein the reflective coating layer is disposed between the transition zone structure and the first surface side of the light guide plate.