Multilayer reflector with selective transmission

A selectively transmissive reflector comprising:

• a dielectric stack of optical repeating units including at least two different materials having different refractive indices, the dielectric stack being designed to substantially reflect light of a predetermined wavelength when the light propagates in the film at a propagation angle within a first group of angles and to substantially transmit the light when the light propagates in the film at a propagation angle within a second group of angles, one of the first group and the second group of angles including angles above a critical angle;
• a first surface optically coupled to the dielectric stack and selectively treated to couple at least a portion of light at the predetermined wavelength, having a propagation angle in the dielectric stack above the critical angle, between the dielectric stack and a medium surrounding the first surface;
• and
• a second surface selectively treated to couple at least a portion of light, having a propagation angle in the dielectric stack above the critical angle, between the dielectric stack and a medium surrounding the second surface, wherein a coupling efficiency of at least one of the first and second surfaces for coupling light having a propagation angle in the dielectric stack that exceeds the critical angle is different for different regions of the dielectric stack.

A selectively transmissive reflector comprising:

• a dielectric stack of optical repeating units including at least two different materials having different refractive indices, the dielectric stack having a first reflection characteristic for light of a particular wavelength propagating in the stack at a propagation angle less than a first angle and a second reflection characteristic for light of the particular wavelength propagating in the stack at a propagation angle greater than a second angle, the second angle being greater than or equal to the first angle;
• a first surface optically coupled to the dielectric stack and selectively treated to couple at least a portion of light at the particular wavelength into the dielectric stack at a propagation angle in the dielectric stack above the second angle;
• and
• a second surface selectively treated to couple at least a portion of light at the particular wavelength and propagating in the stack at a propagation angle above the second angle out of the stack, wherein a coupling efficiency of at least one of the first and second surfaces is different for different regions of the dielectric stack.

An optical film, comprising:

• a multilayer stack of dielectric materials including layers of at least two different materials having different refractive indices along at least one in-plane axis of the film, the layers forming consecutive parallel planes, the multilayer stack being bounded by a first surface layer having an index of refraction n1 and a second surface layer;
• an input layer disposed on at least a portion of the first surface layer to direct at least a portion of light incident on the input layer into the first surface layer at a transmission angle θt, measured from an axis normal to the plane of the first surface layer, which satisfies the relationship
• θt<sin−1(1/n1);
• and
• an output layer disposed on at least a portion of the second surface layer to permit at least a portion of light transmitted through the multilayer stack at the transmission angle θt to exit the optical film through the output layer.

A selectively transmissive reflector, comprising:

• a multilayer dielectric stack having a first surface and a second surface, the dielectric stack substantially reflecting light within a predetermined bandwidth, a bandedge of the bandwidth being defined by a maximum angle of propagation through the dielectric stack for light incident directly on the first surface;
• an input layer formed on at least a portion of the first surface to permit light within the predetermined bandwidth to enter the dielectric stack at a propagation angle which exceeds the maximum angle;
• and
• an output layer formed on at least a portion of the second surface to prevent total internal reflection of the light propagating through the dielectric mirror at the propagation angle which exceeds the maximum angle such that light is selectively transmitted through the mirror at locations corresponding to the input and output layer.

A selectively transmissive mirror, comprising:

• a multilayer stack of dielectric materials having a first and second surface and including layers of at least two different materials having different refractive indices along at least one in-plane axis of the film, the stack substantially reflecting light incident on the film within a predetermined bandwidth, the bandedge of the bandwidth being selected to reflect light propagating through the dielectric stack at a predetermined propagation angle;
• a first treatment applied to at least a portion of the first surface, wherein at least a portion of any light within the predetermined bandwidth incident on the treated portion of the first surface is directed into the dielectric stack at a propagation angle which exceeds the predetermined propagation angle and wherein at least a portion of any light propagating through the dielectric stack from the second surface at an angle which exceeds the predetermined propagation angle exits the dielectric at the treated portion of the first surface;
• and
• a second treatment applied to at least a portion of the second surface, wherein at least a portion of any light within the predetermined bandwidth incident on the treated portion of the second surface is directed into the dielectric stack at a propagation angle which exceeds the predetermined propagation angle and wherein at least a portion of any light propagating through the dielectric stack from the first surface at an angle which exceeds the predetermined propagation angle exits the dielectric at the treated portion of the second surface, the second treatment being applied such that an amount of any light within the predetermined bandwidth directed into the dielectric stack through the second surface at a propagation angle which exceeds the predetermined propagation angle or an amount of any light exiting the dielectric stack through the second surface varies for different portions of the second surface.