Waveguide and video image display device

A video image display device comprising:

• a video image generation unit that generates video image light;
• a coupling prism;
• and
• a waveguide, wherein
• the waveguide includes
• an incident surface on which video image light is incident,
• first and second internal reflection surfaces that propagate the video image light incident from the incident surface while totally reflecting the video image light, and are substantially parallel to each other, and
• a plurality N of partial reflection surfaces that reflect a part of the video image light propagating by being totally reflected by the first and second internal reflection surfaces, output the part of the video image light as output light from the first internal reflection surface to the outside of the waveguide, and transmit the part of the video image light being incident, and are disposed in substantially parallel to each other inside the waveguide, and
• intensity Ik of output light reflected by a k-th (k is an integer of equal to or greater than 1 and equal to or less than N) partial reflection surface is equal to or greater than intensity I(k+1) of output light reflected by a (k+1)-th partial reflection surface disposed adjacent to the k-th partial reflection surface in a direction away from the incident surface,
• wherein the coupling prism includes a first surface on which the video image light generated by the video image generation unit is incident and a second surface from which the video image light being incident is emitted to the incident surface of the waveguide,
• wherein when an angle formed between the partial reflection surface and the second internal reflection surface is θ, an angle formed between the first internal reflection surface and the first surface is substantially 2θ, and
• wherein the incident surface and the second surface are substantially parallel to each other.