Stereoscopic display device

A display device comprising:

• a backlight configured to provide coherent light and comprises a light source, and
• a stack of layers traversed by light emitted from the backlight, wherein the stack of layers comprises:
• a masking layer comprising an array of optical elements, wherein at least some of the optical elements are diffractive optical elements, and
• a display layer comprising an array of amplitude light modulators,
• wherein the array of optical elements comprises at least two types of optical elements, wherein the types differ in their output angular distribution,
• wherein the backlight comprises an optical device having a first waveguide and a second waveguide for guiding light beams emitted from the light source, wherein light beams guided by different waveguides arrive at different areas of the masking layer, wherein each of the light beams arriving at the masking layer from each waveguide is coherent,
• wherein the optical device further comprises a bus waveguide, a first optical coupler, and a second optical coupler, wherein the first optical coupler is configured to couple the light beams emitted from the light source from the bus waveguide to the first waveguide, and the second optical coupler is configured to couple the light beams emitted from the light source from the bus waveguide to the second waveguide.