CPC G02B 6/0038 (2013.01) [G02B 6/0065 (2013.01); G02B 6/0076 (2013.01); G02B 27/0172 (2013.01); G02B 2027/0112 (2013.01)] | 14 Claims |
1. A diffractive waveguide stack comprising:
a first diffractive waveguide for guiding light in a first visible wavelength range, the first diffractive waveguide comprising a first material and having a first refractive index and a first yellowness index at a selected wavelength, and a first target refractive index at a midpoint of the first visible wavelength range; and
a second diffractive waveguide for guiding light in a second visible wavelength range, the second diffractive waveguide comprising a second material and having a second refractive index and a second yellowness index at the selected wavelength, and a second target refractive index at a midpoint of the second visible wavelength range; and
a third diffractive waveguide for guiding light in a third visible wavelength range, the third diffractive waveguide comprising a third material and having a third refractive index and a third yellowness index at the selected wavelength, and a third target refractive index at a midpoint of the third visible wavelength range,
wherein:
the first material differs from the second material and the third material, and the second material differs from the third material,
the first visible wavelength range comprises red light, the second visible wavelength range comprises green light, and the third visible wavelength range comprises blue light,
the first yellowness index exceeds the second yellowness index at the selected wavelength, and the second yellowness index exceeds the third yellowness index at the selected wavelength, and
a difference between any two of the first target refractive index, the second target refractive index, and the third target refractive index is less than 0.005.
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