Spatial optical differentiators and layer architectures for oled display pixels

A method of fabricating a functional unit for an electroluminescent (EL) device pixel, the method comprising:

• forming a first layer of a spatial optical differentiator adjacent the EL device pixel, the first layer having a first refractive index;
• forming a second layer of the spatial optical differentiator over the first layer, the second layer having a second refractive index, wherein a difference between the first and second refractive indices is about 0.2 or greater;
• forming a third layer of the spatial optical differentiator over the second layer, the third layer having the first refractive index;
• and
• forming a fourth layer of the spatial optical differentiator over the third layer, the fourth layer having the second refractive index, wherein the spatial optical differentiator is configured to selectively reflect and transmit light based on an incident angle of light upon the functional unit.

A display structure, comprising:

• an array of electroluminescent (EL) device pixels;
• a functional unit disposed adjacent the array of EL device pixels, the functional unit comprising:
• a spatial optical differentiator disposed adjacent the EL device pixel, wherein the spatial optical differentiator is configured to selectively reflect and transmit light based on an incident angle of light upon the functional unit;
• a plurality of thin-film transistors forming a driving circuit array configured to drive and control the array of EL device pixels;
• and
• a plurality of interconnection layers, each interconnection layer in electrical contact between an EL pixel and a respective thin-film transistor of the plurality of thin-film transistors.