Luminaire module having a light guide with a redirecting end-face

Abstract

A solid-state luminaire module includes one or more light-emitting elements (LEEs) arranged to provide light; and a light guide including a receiving end arranged to receive the light provided by the LEEs and an opposing end, a pair of opposing side surfaces extending along a length of the light guide to guide the received light in a forward direction to the opposing end, and a redirecting end-face located at the opposing end and configured to reflect the guided light—that reaches the opposing end—back into the light guide as return light, such that substantially all the return light impinges on the pair of opposing side surfaces at incident angles larger than a critical incidence angle and transmits through the pair of opposing side surfaces into the ambient as output light of the luminaire module, the output light to propagate in backward directions.

1 - 14 . (canceled) 
     
     
         15 . A luminaire module comprising:
 one or more light-emitting elements (LEEs);   a light guide comprising a receiving end arranged to receive light from the LEEs, an opposing end opposite the receiving end, and a side surface extending along a length of the light guide between the receiving end and the opposing end, the light guide configured to guide at least some of the light received at the receiving end along a forward direction via reflection of the light at the side surface to the opposing end of the light guide; and   a redirecting end-face located at the opposing end of the light guide, the redirecting end-face comprising microscopic surface structure and being configured to reflect at least some of the guided light back into the light guide as return light that impinges on the side surface at incident angles less than a critical angle allowing transmission of at least some of the return light from the light guide into an ambient environment as output light, the output light propagating in backward directions including obtuse angles relative to the forward direction.   
     
     
         16 . The luminaire module of  claim 15 , wherein the microscopic surface structure comprises a plurality of grooves. 
     
     
         17 . The luminaire module of  claim 16 , wherein the grooves are v-grooves or grooves defining a sawtooth pattern. 
     
     
         18 . The luminaire module of  claim 16 , wherein the grooves are symmetric grooves. 
     
     
         19 . The luminaire module of  claim 16 , wherein the grooves comprise planar facets. 
     
     
         20 . The luminaire module of  claim 16 , wherein the grooves comprise curved facets. 
     
     
         21 . The luminaire module of  claim 15 , wherein the microscopic surface structure comprises a plurality of parallel facets. 
     
     
         22 . The luminaire module of  claim 15 , wherein the microscopic surface structure comprises a plurality of curved facets. 
     
     
         23 . The luminaire module of  claim 15 , wherein the microscopic surface structure defines a plurality of apexes spaced apart from one another across a width of the redirecting end-face. 
     
     
         24 . The luminaire module of  claim 15 , wherein the light guide guides the guided light only by total internal reflection. 
     
     
         25 . The luminaire module of  claim 15 , further comprising an optical coupler having an input aperture and an exit aperture, the optical coupler arranged to receive light from the LEEs within a first angular range via the input aperture and arranged to provide light to the receiving end of the light guide within a second angular range via the exit aperture, wherein the light guide guides all light within the second angular range along the forward direction to the opposing end of the light guide. 
     
     
         26 . The luminaire module of  claim 25 , further comprising multiple of said optical couplers. 
     
     
         27 . The luminaire module of  claim 26 , wherein the multiple optical couplers are arranged along a path in a plane perpendicular to the forward direction and the light guide is an elongate light guide extending along the path. 
     
     
         28 . The luminaire module of  claim 15 , wherein the light guide is a solid light guide. 
     
     
         29 . The luminaire module of  claim 15 , wherein the light guide comprises a first material and the side surface of the light guide comprises a layer of a second material. 
     
     
         30 . The luminaire module of  claim 29 , wherein the layer comprises a coating. 
     
     
         31 . The luminaire module of  claim 29 , wherein the second material is a reflective material. 
     
     
         32 . The luminaire module of  claim 15 , wherein the redirecting end-face comprises a reflective coating. 
     
     
         33 . The luminaire module of  claim 32 , wherein the reflective coating comprises transparent portions. 
     
     
         34 . The luminaire module of  claim 15 , wherein the redirecting end-face includes light-transmitting portions that transmit guided light into the ambient environment. 
     
     
         35 . The luminaire module of  claim 15 , wherein the side surface comprises pairs of opposing faces. 
     
     
         36 . The luminaire module of  claim 35 , wherein the opposing faces are parallel opposing faces. 
     
     
         37 . The luminaire module of  claim 15 , wherein a shape of the light guide is a rectangular cuboid. 
     
     
         38 . The luminaire module of  claim 15 , wherein a shape of the light guide is a cylindrical shell. 
     
     
         39 . The luminaire module of  claim 15 , wherein a shape of the light guide is a right circular cylinder. 
     
     
         40 . The luminaire module for  claim 15 , wherein the microscopic surface structure comprises structures formed by molding, mechanical machining or laser formation. 
     
     
         41 . The luminaire module of  claim 15 , wherein the redirecting end-face transmits no guided light. 
     
     
         42 . The luminaire module of  claim 15 , wherein the microscopic surface structure splits the guided light into the return light and transmitted light, and wherein the redirecting end-face outputs at least some of the transmitted light in directions including acute angles relative to the forward direction into the ambient environment. 
     
     
         43 . The luminaire module of  claim 15 , wherein the microscopic surface structure of the redirecting end-face extends in a plane perpendicular to the forward direction.