An illumination device suppresses a variation in color tone caused by a difference in optical path length from a light source without requiring a complicated manufacturing process. The illumination device includes: a single light source emitting monochromatic light; a light guide body transmitting the light emitted from the light source; a plurality of light emitting portions provided at positions having different optical path lengths from the light source, respectively, to transmit the light; and color conversion layers disposed between the light emitting portions and the light guide body to convert a color of the light transmitted through the light guide body.

Disclosed herein is a waveguide-based display comprising: a waveguide, a source of image modulated light projected over a field of view; an input coupler for coupling said light into a total internal reflection (TIR) path within the waveguide; and a grating structure for providing beam expansion of the TIR light in at least one direction and extracting the TIR light from the waveguide. The grating structure may include a plurality of grating elements having at least two different grating prescriptions and at least one surface relief grating formed by a phase separation process.

Disclosed is an imaging directional backlight including an array of light sources, and a control system arranged to provide variable distribution of luminous fluxes, scaled inversely by the width associated with the respective light sources in the lateral direction, across the array of light sources. The luminous intensity distribution of output optical windows may be controlled to provide desirable luminance distributions in the window plane of an autostereoscopic display, a directional display operating in wide angle 2D mode, privacy mode and low power consumption mode. Image quality may be improved and power consumption reduced.

A transaction card includes at least one metal layer having one or more apertures therein. A light guide is disposed beneath the metal layer. The light guide has a light output and a light input. The light output is positioned to transmit light through at least the one or more apertures of the metal layer. At least one LED is positioned to transmit light into the light guide light input

An imaging directional backlight apparatus including a waveguide, a light source array, for providing large area directed illumination from localized light sources. The waveguide may include a stepped structure, in which the steps may further include extraction features optically hidden to guided light, propagating in a first forward direction. Returning light propagating in a second backward direction may be refracted, diffracted, or reflected by the features to provide discrete illumination beams exiting from the top surface of the waveguide. The directional backlight may be arranged to switch between at least a first wide angular luminance profile mode and a second narrow angular luminance profile mode. The directional backlight is arranged to illuminate an LCD with a bias electrode arranged to switch liquid crystal directors in black state pixels between a first wide angular contrast profile mode and a second narrow angular contrast profile mode. Performance of privacy operation for off-axis snoopers is enhanced in comparison to displays with only directional backlights or switchable contrast properties.

A plasma etching method using a Faraday cage, comprising: providing a Faraday cage having a mesh portion on an upper surface thereof in a plasma etching apparatus; providing a quartz substrate having a metal mask with an opening provided on one surface of the metal mask in the Faraday cage; and patterning the quartz substrate with plasma etching.

Provided is a display module, including: a shell; a display panel, wherein the display panel is disposed in the shell and is connected to the shell; a first light emitting component, wherein the first light emitting component is connected to the display panel and is configured to emit light of a target wavelength; and a fingerprint recognition sensor, wherein the fingerprint recognition sensor is disposed between the shell and the display panel and is fixedly connected to the shell; an orthographic projection of the fingerprint recognition sensor onto the display panel and an orthographic projection of the first light emitting component onto the display panel do not overlap; and the fingerprint recognition sensor is configured to recognize a fingerprint based on received light of the target wavelength reflected by an obstacle.

Techniques for overcoating slanted structures and devices obtained using the techniques are disclosed. In some embodiments, a method of forming an overcoat layer on a surface-relief structure on a substrate includes receiving the substrate with the surface-relief structure. The surface-relief structure includes a plurality of ridges slanted with respect to the substrate, and a plurality of grooves each between two adjacent ridges. The method further includes depositing, in each cycle of a plurality of cycles, a uniform layer of an overcoat material on surfaces of the plurality of ridges and bottoms of the plurality of grooves. The deposited layers of the overcoat material and the plurality of ridges collectively form a light-coupling structure on the substrate. A surface of the overcoat layer is planar.

An electronic device may have light-emitting devices. A light-emitting device may include light-emitting diodes, a display, or other components that emit visual output. One or more image transport layers may be included in the electronic device. An image transport layer may have an input surface that receives an image and an output surface to which the image transport layer transports the image for viewing by a user. The image transport layers may have areas with compound curvature and other shapes. Deformed image transport layer structures such as deformed fibers in a coherent fiber bundle may be configured to hide gaps in displays and other structures. Displays may include light detectors that serve as a two-dimensional touch sensor. The touch sensor may detect touch input on an output surface of an image transport layer. Image transport layer material may be incorporated into buttons, elongated housings, wearable devices, and other equipment.

The present disclosure provides a metal back plate and a manufacturing process thereof, a backlight module and an electronic device. The metal back plate is used for the backlight module. The metal back plate includes a first area and a second area. The grain size of the metal material in the first area is larger than the grain size of the metal material in the second area. The first area is formed with a first opening.