Image combiner and image display unit

摘要

A plate part is positioned in front of the eye of the user. An image combiner causes light from an image display element to be superimposed on light that is transmitted through the plate part and conducts this light to the eye. The light from the image display element reaches the eye after being diffracted and reflected by a reflective type HOE inside the plate part. The wavelength at which the diffraction efficiency shows a maximum value when the chief rays that are emitted from the center of the display part of the image display element are diffracted and reflected by the reflective type HOE and the wavelength at which the diffraction efficiency shows a maximum value when the chief rays that are emitted from the peripheral portions of the display part in a specified direction are diffracted and reflected by the reflective type HOE are substantially different.