Transparent LED layer between phosphor layer and light exit surface of lamp

摘要

A flexible light sheet lamp includes a thin substrate and an array of printed microscopic vertical LEDs (VLEDs) sandwiched between a transparent first conductor layer and a transparent second conductor layer. The light sheet has a light exit surface. The VLEDs have one surface, facing the light exit surface of the light sheet, covered with a reflective metal. A phosphor layer is provided such that the semi-transparent VLED layer is between the phosphor layer and the light exit surface. A reflector layer is provided such that the phosphor layer is between the reflector layer and the VLED layer. The substrate may form the light exit surface or the light exit surface may be the opposite side of the light sheet. Some VLED light passing through the phosphor layer is reflected by the reflector layer and re-enters the phosphor layer. Therefore, less phosphor is needed to achieve the desired conversion ratio.

主权项

1. An illumination structure having a light exit surface, the structure comprising:
a substrate; a transparent first conductor layer overlying the substrate; an array of vertical light emitting diodes (VLEDs), the VLEDs having a bottom electrode electrically contacting the first conductor layer, the VLEDs having a first surface covered with a reflective material such that a majority of all light emitted by the VLEDs is emitted through a second surface, opposite the first surface, wherein the first surface faces the light exit surface of the illumination structure; a transparent second conductor layer overlying the VLEDs, the VLEDs having a top electrode electrically contacting the second conductor layer; the VLEDs being illuminated by a voltage differential between the first conductor layer and the second conductor layer such that light passes through the first conductor layer and the second conductor layer; a wavelength-conversion layer having a third surface facing the second surface of the VLEDs, the wavelength-conversion layer having a fourth surface opposite the third surface; and a reflector layer opposing the fourth surface of the wavelength-conversion layer, such that the wavelength-conversion layer is between the array of VLEDs and the reflector layer, wherein at least some light emitted from the second surface of the VLEDs and some of the light emitted from the wavelength-conversion layer is reflected by the reflector layer to reenter the wavelength-conversion layer and ultimately exit through the light exit surface.