A planar light source includes: a light guide plate including: a first principal face, a second principal face located opposite the first principal face, and a plurality of through holes that are open at the first principal face and the second principal face; a plurality of light sources, wherein at least one of the light sources is located in the through holes of the light guide plate; a wiring substrate on which the plurality of light sources are located; a first light transmissive member located in a first of the through holes so as to cover at least a portion of a lateral face of the at least one light source located in the first through hole; and a second light transmissive member located in the first through hole so as to cover at least an upper face of the first light transmissive member.

An eyepiece for projecting an image to an eye of a viewer includes a waveguide configured to propagate light in a first wavelength range, and a grating coupled to a back surface of the waveguide. The grating is configured to diffract a first portion of the light propagating in the waveguide out of a plane of the waveguide toward a first direction, and to diffract a second portion of the light propagating in the waveguide out of the plane of the waveguide toward a second direction opposite to the first direction. The eyepiece furthers include a wavelength-selective reflector coupled to a front surface of the waveguide. The wavelength selective reflector is configured to reflect light in the first wavelength range and transmit light outside the first wavelength range, such that the wavelength-selective reflector reflects at least part of the second portion of the light back toward the first direction.

An eyepiece includes a planar waveguide having a front surface and a back surface. The eyepiece also includes a grating coupled to the back surface of the planar waveguide and configured to diffract a first portion of the light propagating in the planar waveguide out of a plane of the planar waveguide toward a first direction and to diffract a second portion of the light propagating in the planar waveguide out of the plane of the planar waveguide toward a second direction opposite to the first direction and a wavelength-selective reflector coupled to the front surface of the planar waveguide. The wavelength-selective reflector comprises a multilevel metasurface comprising a plurality of spaced apart protrusions having a pitch and formed of a first optically transmissive material and a second optically transmissive material disposed between the spaced apart protrusions.

There is provided an optical element including a light guide, an incoupler, and a beam splitter disposed in an optical path of a display beam between the incoupler and a light engine to generate the display beam. The display beam may comprise first and second beams. The beam splitter may split the display beam to form a first offspring beam including the first beam and a first portion of the second beam, and to form a second offspring beam including a second portion of the second beam. The first and second offspring beams may be incident upon the incoupler at first and second incidence positions respectively. The first incidence position may be different than the second incidence position. The incoupler may direct at least a portion of each of the first and second offspring beams into the light guide to form incoupled first and second offspring beams respectively.

Systems and methods to reduce diffraction-angle effects, such as instances of double-bounces and bounce separation spacing effects in a laser projection system including an optical engine with laser diodes configured to emit light beams of different wavelengths and a beam combiner having a reflective surfaces each configured to receive one of the light beams from one of the laser diodes and to reflect the received light beam such that an edge of the reflected light beam lies on a tangent common to the other light beams reflected from the other reflective surfaces. The laser projection system may be implemented in head-mounted display (HMD) including a waveguide having an incoupler to receive the combined light beam, where an edge of the incoupler corresponds to the tangent on which the edges of the plurality of light beams are aligned.

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 light emitting device includes light emitting elements, light-transmissive members, a covering member, at least one first protrusion, and two second protrusions. The light emitting elements are aligned in a first direction. The light-transmissive members are respectively disposed on upper surfaces of the light emitting elements. The covering member includes at least one first covering portion and two second covering portions. The at least one first covering portion is arranged between adjacent ones of the light-transmissive members, and the second covering portions are arranged at distal ends of the light emitting device in the first direction with the light-transmissive members being arranged between the second covering portions. The at least one first protrusion is arranged on an upper surface of the at least one first covering portion and being spaced apart from the light-transmissive members. The second protrusions respectively arranged on upper surfaces of the second covering portions.

An optical structure includes a grating coupler and a microlens. The grating coupler is configured to receive a laser light. The microlens is above the grating coupler, in which a metal shielding covers the microlens and has an opening to allow the laser light entering an effective coupling region of the grating coupler.

An optical system includes a light module, an optical element on a first grating coupler, and a second grating coupler. The light module emits three beams from different positions. The optical element is below the light module and is configured to change incident angles of the three beams and to focus the three beams at the same region of the first grating coupler. The first grating coupler is below the optical element and is configured to couple the three beams into a light-guide substrate. The light-guide substrate is connected to the first grating coupler and is configured to transmit the three beams. The second grating coupler is connected to the light-guide substrate and is configured to enable the three beams departing from the light-guide substrate after the three beams have traveled the same optical path.

An optical film, a method for manufacturing the same, and a backlight module are provided. The optical film is formed by a cadmium-free quantum dot gel layer, which includes a first polymer and a plurality of cadmium-free quantum dots dispersed therein. The first polymer includes: 1 wt % to 5 wt % of a photoinitiator; 3 wt % to 30 wt % of scattering particles; 10 wt % to 40 wt % of a thiol compound; 5 wt % to 30 wt % of a monofunctional acrylic monomer; 5 wt % to 20 wt % of a bifunctional acrylic monomer; 10 wt % to 40 wt % of a multifunctional acrylic monomer; 5 wt % to 20 wt % of an organosilicon grafted oligomer; and 100 ppm to 2,000 ppm of an inhibitor. The thiol compound includes a primary mercaptan and a secondary mercaptan, and a weight ratio of the primary mercaptan to the secondary mercaptan ranges from 1:3 to 3:1.