Waveguide having unidrectional illuminance

A luminaire, comprising:

• a transparent optical waveguide comprising a primary light-emitting surface and a secondary surface opposite the primary light-emitting surface;
• a light source coupled to the transparent optical waveguide;
• a plurality of light extraction features disposed on the primary light-emitting surface;
• and
• wherein the plurality of light extraction features comprises a first portion adjacent to the primary light-emitting surface and a second portion distal from the primary light-emitting surface, and wherein the first portion comprises a truncated hemispherical shape in cross section and the second portion comprises one of a truncated conical shape and a cylindrical shape in cross section such that light is directionally extracted from the primary light-emitting surface in a direction away from the secondary surface to illuminate a surrounding that is viewable through the transparent optical waveguide;
• a housing wherefrom the luminaire is vertically suspended for providing general illumination lighting in a direction away from a viewer.

A method of illumination using an optical waveguide comprising a primary light-emitting surface and a secondary surface opposite the primary light-emitting surface, the method comprising:

• providing the optical waveguide;
• injecting light into the optical waveguide;
• and
• wherein the waveguide comprises a plurality of light extraction features that produce an illumination characteristic resulting from the plurality of extraction features directing light out of the optical waveguide away from the primary light-emitting surface;
• wherein the plurality of light extraction features comprises a first portion adjacent to the primary light-emitting surface and a second portion distal from the primary light-emitting surface;
• and
• wherein the first portion comprises a truncated hemispherical shape in cross section and the second portion comprises one of a truncated conical shape and a cylindrical shape in cross section;
• directionally extracting light from the primary light-emitting surface through the plurality of light extraction features in a direction away from the secondary surface to direct light onto an object that is viewable through the secondary surface and the primary light-emitting surface.

A method of illumination using an optical waveguide comprising a primary light-emitting surface and a secondary surface opposite the primary light-emitting surface, the method comprising:

• providing the optical waveguide;
• disposing a plurality of light extraction features onto the primary light-emitting surface, the plurality of light extraction features comprising a first portion adjacent to the primary light-emitting surface and a second portion distal from the primary light-emitting surface, wherein the first portion comprises a truncated hemispherical shape in cross section and the second portion comprises one of a truncated conical shape and a cylindrical shape in cross section;
• injecting light into the optical waveguide;
• arranging a light source within a housing;
• mounting the optical waveguide on the housing wherein a coupling end of the optical waveguide is disposed in the housing adjacent to the light source;
• and
• directionally extracting light from the primary light-emitting surface through the plurality of light extraction features in a direction away from the secondary surface to direct at least 95% of the injected light out of the optical waveguide and onto an object that is viewable through the secondary surface and the primary light-emitting surface.