Optical films are disclosed. More particularly, optical films including a collimating reflective polarizer are disclosed. The optical films are useful in backlights, and in particular backlight recycling cavities. Constructions suitable with both edge-lit and direct-lit backlights are disclosed.

A backlight module and a display device are provided. The backlight module includes a polarizing light guide plate configured to convert incident light into first polarized light and second polarized light, a polarization direction of the first polarized light being perpendicular to a polarization direction of the second polarized light.

An illuminating device includes: a light source; a light guide plate which converts light emitted from the light source into a surface light ray and emits the surface light ray through a front surface of the light guide plate; and an optical sheet which changes a propagation direction of the surface light ray emitted from the light guide plate. The light source is arranged in opposition to one end surface of the light guide plate. A polarization state converting structure to convert a polarization state of the light propagating through the light guide plate is provided in a rear surface of the light guide plate. The polarization state converting structure contains an inclination plane having a ridge line extending in a direction perpendicular to the extension direction of the one end surface.

A display device includes a light source module, a first light modulation module, a first polarizer layer, and a first color modulation layer. The light source module generates a first color light that is polarized to the first light modulation module, wherein the first light modulation module selectively modulates the polarization direction of the first color light. The first polarizer layer then receives the first color light and selectively blocks, partially blocks, or does not block the first color light from passing through. The first color modulation layer receives the first color light and generates a second color light.

Embodiments include an optical system that may be included in a waveguide display. An example apparatus includes an image generator configured to generate an image having an upper portion and a lower portion. A waveguide is provided with an in-coupler and an out-coupler, the in-coupler being arranged to couple the upper and lower portions of the image along an optical path to the out-coupler. Along the optical path, at least first and second polarization-selective diffraction gratings are configured to cooperatively direct the upper portion of the image toward the out-coupler. At least third and fourth polarization-selective diffraction gratings are configured to cooperatively direct the lower portion of the image toward the out-coupler.

A switchable directional backlight for a privacy display comprises a waveguide with first and second opposing input ends and a turning film arranged to collect light output from the waveguide for input into a spatial light modulator. The waveguide has an array of light deflecting features arranged on one guiding surface and an opposing planar surface. Light deflecting features are arranged such that light input from the first input end is output with a narrow angular range and light input from the second input end is output with a wide angular range.

A display device includes an image projector and a pupil-replicating lightguide having an out-coupling grating with configurable dynamic spatial distribution of out-coupling efficiency that may be adjusted depending upon several factors including currently displayed portion of the field of view as well as the eye position and orientation at the eyebox of the display device. For scanning display systems, the out-coupling grating may be configured to have a high-efficiency grating area that “runs” along the grating in coordination with the scanning to provide a more efficient light utilization in the display device.

A switchable privacy display comprises a spatial light modulator (SLM), a first switchable liquid crystal (LC) retarder and first passive retarder between a first pair of polarisers and a second switchable LC retarder and second passive retarder between a second pair of polarisers. The first switchable LC retarder comprises two homeotropic alignment layers and the second switchable LC retarder comprises two homogeneous alignment layers. In privacy mode, on-axis light from the SLM is directed without loss, whereas off-axis light has reduced luminance to reduce visibility to off-axis snoopers. The display may achieve privacy operation in landscape and portrait orientations. Further, display reflectivity may be reduced for on-axis reflections of ambient light, while reflectivity may be increased for off-axis light to achieve increased visual security. In public mode, the LC retardance is adjusted so that off-axis luminance and reflectivity are unmodified. The display may switch between day-time and night-time operation.

A light source module including a first backlight module, a second backlight module, a turning film, and a first absorptive polarizer film is provided. The first backlight module has a first side and a second side. The first backlight module includes a first light guide plate (LGP) having a first light incident surface and a first light source disposed beside the first light incident surface. The second backlight module is arranged at the second side. The second backlight module includes a second LGP having a second light incident surface and a second light source disposed beside the second light incident surface. The turning film is arranged at the first side. The turning film includes a plurality of reverse prisms. The reverse prisms extend along an extension direction. The first absorptive polarizer film is disposed between the first backlight module and the second backlight module. A display device is also provided.

Display devices include waveguides with metasurfaces as in-coupling and/or out-coupling optical elements. The metasurfaces may be formed on a surface of the waveguide and may include a plurality or an array of sub-wavelength-scale (e.g., nanometer-scale) protrusions. Individual protrusions may include horizontal and/or vertical layers of different materials which may have different refractive indices, allowing for enhanced manipulation of light redirecting properties of the metasurface. Some configurations and combinations of materials may advantageously allow for broadband metasurfaces. Manufacturing methods described herein provide for vertical and/or horizontal layers of different materials in a desired configuration or profile.