Light Management System with Distributed Light Input Ports and Light-Converting Layer

A light management system, comprising:

• a source of visible light configured to emit light at least in a first spectral band;
• a front surface configured to reflect light incident within a first angular range by total internal reflection and to transmit light incident within a second angular range different from the first angular range;
• a back sheet formed from an opaque reflective material and configured to reflect and scatter light, the back sheet being approximately coextensive in size with the front surface and spaced apart from the front surface, wherein the front surface and the back sheet are disposed in optical energy exchange relationship and cooperatively define a planar light-trapping structure configured to at least partially confine light between the front surface and the back sheet;
• a light converting layer approximately coextensive in size with and positioned between the front surface and the back sheet, the light converting layer having a monolithic sheet structure and comprising an active layer formed from an optically transmissive material, the active layer comprising a first light converting material having a first bandgap and a second light converting material having a second bandgap different from the first bandgap, at least one of the first or second light converting materials configured to absorb light in the first spectral band, at least one of the first or second light converting materials comprising quantum dots embedded in the optically transmissive material;
• a plurality of light input ports distributed across the planar light-trapping structure and configured to admit light from the source into a space between the front surface and the back sheet at a plurality of regions distributed across the planar light-trapping structure, a cumulative area of the plurality of light input ports being no more than approximately 10% of a total area of the planar light-trapping structure;
• and
• a plurality of optical elements, each of the plurality of optical elements being disposed in registration with a respective one of the plurality of light input ports and configured to angularly redistribute light emitted by the source,
• wherein the active layer has a thickness less than a thickness sufficient to absorb substantially all light in the first spectral band in a single transverse pass through the active layer, and wherein the planar light-trapping structure is configured to cause at least a portion of the light in the first spectral band to pass through the active layer multiple times.

A method of making a light management system, comprising:

• providing a source of visible light configured to emit light at least in a first spectral band;
• providing an optically transmissive sheet having a front surface, the front surface configured to reflect light having an incidence angle within a first angular range by total internal reflection, and to transmit light having an incidence angle within a second angular range different from the first angular range;
• providing a back sheet formed from an opaque reflective material and configured to reflect and scatter light, the back sheet being approximately coextensive in size with the front surface;
• providing a light converting layer having a monolithic sheet structure and comprising an active layer formed from an optically transmissive material, the active layer comprising a first light converting material having a first bandgap and a second light converting material having a second bandgap different from the first bandgap, at least one of the first or second light converting materials configured to absorb light in the first spectral band, at least one of the first or second light converting materials comprising quantum dots embedded in the optically transmissive material, the light converting layer being approximately coextensive in size with the front surface;
• providing a plurality of light input ports distributed in a two-dimensional array of rows and columns and configured to admit light from the source into a space between the front surface and the back sheet, a cumulative area of the plurality of light input ports being no more than approximately 10% of a total area of the front surface;
• providing a plurality of optical elements, each of the plurality of optical elements configured to angularly redistribute light emitted by the source;
• positioning each of the plurality of optical elements in registration with one of the plurality of light input ports;
• positioning the back sheet at a distance from and parallel to the front surface, such that the front surface and the back sheet are disposed in optical energy-exchange relationship and cooperatively define a planar light-trapping structure configured to at least partially confine light between the front surface and the back sheet;
• and
• positioning the light converting layer between the front surface and the back sheet,
• wherein the active layer has a thickness less than a thickness sufficient to absorb substantially all light in the first spectral band in a single transverse pass through the active layer, and wherein the planar light-trapping structure is configured to cause at least a portion of the light in the first spectral band to pass through the active layer multiple times.