Projection unit comprising a volume hologram having a volume grating, and projection device having a projection unit

A projection unit which images a fed multicolored image having a first and a second wavelength into an exit pupil such that an observer can perceive said image as a virtual image when an eye of the observer is positioned in the exit pupil and the observer looks at the projection unit at a predetermined viewing angle, the projection unit comprising:

• a volume hologram, which deflects the multicolored image into the exit pupil for imaging purposes,
• wherein the volume hologram comprises a volume grating introduced by exposure for each wavelength of the color sub-images, the volume grating having a respective deflection efficiency profile which is dependent on the viewing angle and which is maximal for the predetermined viewing angle, and
• wherein the deflection efficiency profiles for a predetermined angular range around the predetermined viewing angle are set to be equal by virtue of the fact that, for each of the volume gratings introduced by exposure, the number of interference maxima introduced by exposure is the same and refractive index modulation introduced by exposure for the corresponding wavelength is the same for the volume gratings introduced by exposure.