Abstract: A display device including a display panel and a backlight module is provided. The backlight module is correspondingly disposed below the display panel and includes light-emitting elements providing light beams and disposed on a circuit board, lens units each being disposed on a corresponding light-emitting element and having a concave inside surface covering the corresponding light-emitting element and a convex outside surface covering the concave inside surface, and an inverse prism sheet disposed between the lens units and the display panel, and the inverse prism sheet having inverse prisms with a vertex corner. At least a portion of the light beams emitted from the convex outside surface each has a predetermined light-emitting angle ?o larger than 30 degrees and less than 90 degrees. The backlight module has a height of cavity D being a distance between the vertex corner and the circuit board, and 10 ?m?D<30 mm.

Abstract: A display device including a display panel and a backlight module is provided. The backlight module is correspondingly disposed below the display panel and includes light-emitting elements providing light beams and disposed on a circuit board, lens units each being disposed on a corresponding light-emitting element and having a concave inside surface covering the corresponding light-emitting element and a convex outside surface covering the concave inside surface, and an inverse prism sheet disposed between the lens units and the display panel, and the inverse prism sheet having inverse prisms with a vertex corner. At least a portion of the light beams emitted from the convex outside surface each has a predetermined light-emitting angle ?o larger than 30 degrees and less than 90 degrees. The backlight module has a height of cavity D being a distance between the vertex corner and the circuit board, and 10 ?m?D<30 mm.

Abstract: A backlight module and a display apparatus are provided. The backlight module comprises a back plate, a light source and at least one light-permeable element. The light source disposed on the back plate has at least one light emitting element. The light-permeable element covers the light emitting element, which comprises a light input surface and a light output surface disposed opposite the light input surface. The light input surface faces the light emitting element and has an apex away from the light emitting element. When viewed from a cross section crossing the apex and perpendicular to the back plate, the light input surface has a first curve and a second curve connected to the first curve. A connection point between the first curve and the second curve is an inflection point.

Abstract: A light emitting device comprising a light emitting element and a secondary optical element is disclosed. The secondary optical element has a light output surface, a light incident surface and a bottom surface. The bottom surface is extended from the light incident surface and connected to the light output surface. The light output surface comprises a planar portion, and a convex curved surface portion. The planar portion is in the center of the light output surface, and the convex curved surface portion is around the planar portion. The light incident surface is a concave curved surface comprising a first curved surface and a second curved surface, which form a concave opening for receiving the light emitting element. The first curved surface is in the center of the light incident surface, and the second curved surface is connected to the bottom surface.