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.