A display backlight, comprises: an excitation source, LED (146), for generating blue excitation light (148) with a peak emission wavelength in a wavelength range 445 nm to 465 nm; and a photoluminescence wavelength conversion layer (152). The photoluminescence wavelength conversion layer (152) comprises a mixture of a green-emitting photoluminescence material with a peak emission in a wavelength range 530 nm to 545 nm, a red-emitting photoluminescence material with a peak emission in a wavelength range 600 nm to 650 nm and particles of light scattering material.

A diffusion lens includes a concave first lens surface, a convex second lens surface such that part of light incident on the first lens surface is output from the second lens surface, a side surface extending from a periphery of the second lens surface in a vertical direction of the diffusion lens such that part of the rest of the light incident on the first lens surface is output from the side surface, and a bottom surface extending from a periphery of the first lens surface in a horizontal direction of the diffusion lens to meet a periphery of the side surface. Rates of change of the first and second lens surfaces have the same sign. A pattern is formed on the side surface and the bottom surface to diffuse the light through the side surface and diffuse the light reflected by the bottom surface.

An electromagnetic flux controlling member includes an incidence surface for allowing incidence of an electromagnetic wave, and an emission surface for emitting the electromagnetic wave incident on the incidence surface to an outside. At least one of the incidence surface and the emission surface includes a base curved surface and a plurality of protrusions arranged on the base curved surface. Each of the plurality of protrusions includes a conical tip portion disposed such that at least a part of an edge of a bottom surface of the conical tip portion makes contact with the base curved surface, and a partially columnar leg portion disposed between the conical tip portion and the base curved surface. A central axis of the conical tip portion and a central axis of the partially columnar leg portion are parallel to a main axis of the electromagnetic flux controlling member.

Provided are a light guide film, a backlight unit, and a display device. Light guide portions are disposed in holes of a reflection plate on which light sources are disposed, and a light guide film is directly disposed on the reflection plate and the light guide portions to provide a light guiding function and a light shielding function. Therefore, a method of facilitating implementation of a backlight unit with a small thickness, which satisfies image quality is provided. Further, each of the light shielding patterns has different reflectances in different areas, thereby increasing the amount of light supplied to an area between light sources. Therefore, a backlight unit with a reduced number of light sources and improved image quality may be provided.

A back light unit includes an array of light emitting diodes, at least two optical films positioned above the array of light emitting diodes, and a pair of brightness enhancement films positioned above the at least two optical films. A majority of the optical films are light splitting optical films having a plurality of light splitting microstructures on at least one surface thereof.

Provided is a backlight unit including: a substrate; a plurality of light-emitting devices mounted on the substrate; and an optical sheet disposed above the light-emitting devices, wherein the optical sheet is in contact with a light-emitting surface of at least one light-emitting device via one surface thereof, and emits light of the light-emitting device incident on one surface thereof to the other surface facing the one surface, while refracting or dispersing the light in a direction different from a direction in which the light is incident due to an optical pattern formed therein.

In described examples, a system (e.g., a projection system) can include a diffractive optical element adapted to be illuminated by at least one coherent light beam. A lens array is coupled to receive a diffracted beam of light from the diffractive optical element. The lens array includes a first and a second array lens. The first array lens is coupled to receive a first sector of a pattern of illumination of the diffracted beam of light, and the second array lens is coupled to receive a second sector of the pattern of illumination of the diffracted beam of light. A spatial light modulator is coupled to receive overlapping diffracted beams of light from the first and second array lenses to form an image beam.

A light emitting device includes a substrate, a conductive layer, first and second reflective layers, a light emitting element, and an encapsulation layer. The conductive layer is disposed on the substrate. The first reflective layer covers the conductive layer and has an opening exposing a portion of the conductive layer. The light emitting element is disposed in the opening and electrically connects to the conductive layer. The second reflective layer is disposed on the first reflective layer and surrounds the light emitting element. The second reflective layer has an outer diameter. A top surface of the second reflective layer is lower than a top surface of the light emitting element. The encapsulation layer covers the light emitting element. There is a height between a highest point of the encapsulation layer and an upper surface of the first reflective layer. The encapsulating layer is directly contact with the outer diameter.

Disclosed is a light diffusing lens having a pointing angle distribution focused toward a lateral direction. The disclosed light diffusing lens includes a light entrance part having a concave shape formed inward from a lower part of the optical diffusing lens, a reflection part having a shape which is concave inward from an upper portion of the light diffusing lens and a light exit portion defined by an outer surface of the light diffusing lens, wherein the light entrance part has a first convex surface which is convex in an optical axial direction defined by a straight line passing through the center of the light diffusing lens as the straight line goes toward the inside of the light diffusing lens.

The present disclosure relates to a light diffusion characteristic and a light reflection characteristic, and a light source device, a backlight unit, and an electronic device that include the lens. By causing the light emitted from the light source of the light source device to have both light diffusibility and light directivity using the lens including a lower layer portion having a light diffusion characteristic and an upper layer portion having a light reflection characteristic, it is possible to improve a light emission characteristic of the light source device, and when an optical gap is reduced due to the thickness reduction of the backlight unit, the image quality of the backlight unit can be improved.