DISPLAY DEVICE AND OPTICAL ELEMENT FOR USE IN SAID DISPLAY DEVICE

A display device 1 includes: an image display element 11 configured to display an image to be displayed; a collimator 12 configured to convert light emitted from each point on the image displayed on the image display element 11 into collimated light; a first light guide 131 formed of a flat plate made of a first material transparent to the light; a second light guide 132 formed of a plate member made of a second material transparent to the light, the second light guide having one surface and the other surface, the one surface of the second light guide being a flat surface in contact with one of surfaces of the flat plate of the first light guide, the other surface of the second light guide being a sawtooth surface 1320; and a beam splitter 133 formed on an interface between the first light guide 131 and the flat surface of the second light guide 132, the beam splitter being configured to transmit a part of the light and reflect the remainder of the light, wherein the sawtooth surface 1320 of the second light guide is configured by alternately combining a first surface 1321 and a second surface 1322, the first surface 1321 being non-parallel to a propagating direction of the light propagating through the second light guide after passing through the interface and being configured to transmit the light, the second surface 1322 being substantially parallel to the propagating direction.