The disclosure relates to the technical field of liquid crystal display, and discloses a backlight module and a display device. The backlight module includes a light guide plate and a plurality of light emitting diodes arranged in a first direction, where the light guide plate is provided with a first region and a second region along a second direction, and the first direction and the second direction intersect with each other; and dots of the first region include a plurality of isolated cluster structures, and a dot density between any two adjacent cluster structures is lower than a dot density of each of the cluster structures.

An optical structure includes a high refractive-index layer and a low refractive-index layer laminated on the high refractive-index layer and having a refractive index lower than that of the high refractive-index layer, and is disposed on a display surface of a display device. An interface between the layers has a concave-and-convex shape, and each of a concavity and a convexity in the shape has a flat portion extending in a surface direction of the layers. A side surface of the concave-and-convex shape, which extends between the flat portions of the concavity and convexity, is a curved surface or a folded surface that is convex to the low refractive-index layer. A difference between a maximum angle and a minimum angle, which are defined between the side surface of the concave-and-convex shape and a normal direction of the layers, is not less than 3 degrees and not more than 60 degrees.

To provide a technique for suppressing brightness non-uniformity of an area illuminated by a light source and also suppressing a decline in contrast between areas caused by incidence of a luminous flux of the area to another area. Provided is a light guide plate including: a diverging portion which is provided on an opposite side of a light exit surface from which light is emitted, the diverging portion causing a luminous flux emitted from a light emitting element to diverge; and a restricting portion which is provided, when a prescribed range from the light emitting element on the light exit surface is defined as an illuminated area illuminated by the light emitting element, in at least a periphery of the illuminated area on the light exit surface and which deflects or shields light traveling from inside toward outside of the illuminated area to restrict traveling, toward a side of the light exit surface, of light traveling toward the outside of the illuminated area.

Provided are a backlight unit and a liquid crystal display device including the backlight unit, the backlight unit being capable of switching between viewing angles in the liquid crystal display device and having a configuration in which the brightness values of emitted light on the “+” side and the “−” side at a polar angle with respect to the normal line are symmetric to each other. The backlight unit includes: a light guide plate; a first light source that guides light into the light guide plate from a long side or a short side of the light guide plate; a second light source that guides light into the light guide plate from a side of the light guide plate different from that of the first light source; a first diffraction element that is provided on one main surface of the light guide plate and diffracts only light emitted from one of the first light source or the second light source; a second diffraction element that is provided on another main surface of the light guide plate and diffracts only light emitted from another one of the first light source or the second light source; and a reflection plate that is provided on a surface of the light guide plate opposite to a light emission surface.

A backlight unit according to various embodiments of the disclosure may include a light source, a light guide plate configured to guide light emitted from the light source and disposed to face in a first direction, and an optical film disposed over the light guide plate. The optical film may include a first prism sheet including first prism structures arranged side by side to each other along a second direction perpendicular to the first direction, and a second prism sheet disposed over the first prism sheet and including second prism structures arranged side by side to each other along a third direction forming an acute angle with the second direction.

A display system including an image source, an optical image deflector unit with an image entry surface, and a first optics arranged between the image entry surface and the image source. The image source generates image information for one or more focal distances which is directed towards the image entry surface by the first optics. The optical image deflector unit includes a first surface and a second surface. The first surface is arranged to reflect the directed image information towards a semi-reflective outcoupling surface, with an angle of incidence higher than a first angle. The semi-reflective outcoupling surface is arranged between the first and the second surface to reflect the reflected one or more image information towards the first surface, with an angle of incidence lower than the first angle. The image entry surface is arranged between the image source and a semi-reflective outcoupling surface.

A light-emitting module includes a light-guiding plate having an upper surface with a first hole and having a rectangular shape in a top view, and a light-emitting element opposite to the first hole and disposed opposite to the upper surface. The first hole includes a first portion and a second portion between the first portion and the upper surface. The first portion is provided with a first opening at a boundary between the first portion and the second portion and a first lateral surface inclined with respect to the upper surface. A shape of the first opening in the top view is defined by a first axis parallel to a short side of the rectangular shape of the light-guiding plate and a second axis parallel to a long side of the rectangular shape and shorter than the first axis in a plan view.

An optical structure includes a high refractive-index layer and a low refractive-index layer laminated on the high refractive-index layer and having a refractive index lower than that of the high refractive-index layer, and is disposed on a display surface of a display device. An interface between the layers has a concave-and-convex shape, and each of a concavity and a convexity in the shape has a flat portion extending in a surface direction of the layers. A side surface of the concave-and-convex shape, which extends between the flat portions of the concavity and convexity, is a curved surface or a folded surface that is convex to the low refractive-index layer. A difference between a maximum angle and a minimum angle, which are defined between the side surface of the concave-and-convex shape and a normal direction of the layers, is not less than 3 degrees and not more than 60 degrees.

A display device capable of minimizing a light loss occurring due to photodiffraction by scattering, through a light scattering unit, light outputted by a light output unit in a given direction is provided. A part for the display device includes a light scattering unit configured to scatter light, and a light guide unit configured to expand the scattered light in a given direction. The light guide unit includes a light guide, a first optical element disposed on one surface or other surface of the light guide and a second optical element disposed on the one surface or the other surface of the light guide.

According to one embodiment, an electronic device includes a liquid crystal panel and an illumination device. The illumination device includes a first light guide having a first opening and facing the liquid crystal panel, a first light source facing the first light guide, a second light guide provided in the first opening and having a first main surface facing the liquid crystal panel, a second main surface, and a side surface, a second light source having a light emitting surface facing the side surface, and a wavelength conversion element located between the side surface and the light emitting surface, and configured to convert a wavelength of light from the second light source.