687results about How to "High diffraction efficiency" patented technology

Architectures are provided for selectively incoupling one or more streams of light from a multiplexed light stream into a waveguide. The multiplexed light stream can have light with different characteristics (e.g., different wavelengths and/or different polarizations). The waveguide can comprise in-coupling elements that can selectively couple one or more streams of light from the multiplexed light stream into the waveguide while transmitting one or more other streams of light from the multiplexed light stream.

Provided are wafer scale lenses having a diffraction surface as well as a refractive surface, and an optical system having the same. The wafer scale lens includes a lens substrate, a first lens element formed on the object side of the lens substrate, having a positive refractive power, a second lens element formed on the image side of the lens substrate, having a diffraction surface, and a third lens element deposited on the diffraction surface of the second lens element, having a negative refractive power. The invention allows miniaturized optical system and efficient calibration of angle of view, reducing the angle of light incident onto the diffractive surface, thereby increasing diffraction efficiency and eliminating high order diffraction light to improve picture quality.

In various embodiments described herein, a device comprising a light collector optically coupled to a photocell is described. The device further comprises a light turning film or layer comprising volume or surface diffractive features or holograms. Light incident on the light collector is turned by volume or surface diffractive features or holograms that are reflective or transmissive and guided through the light collector by multiple total internal reflections. The guided light is directed towards a photocell. In various embodiments, the light collector is thin (e.g., less than 1 millimeter) and comprises, for example, a thin film. The light collector may be formed of a flexible material.

A method of producing a hologram element is disclosed that is able to prevent spread of a polymerization reaction and light leakage during exposure with interference light, and improve productivity in mass production. The hologram element is for transmitting, reflecting, diffracting, or scattering incident light, and includes a pair of substrates, an isolation member between the substrates that forms an isolated region, and a photo-sensitive recording material sealed in the isolated region. The hologram element includes a periodic structure formed by exposing the recording material to interference light. The interference light is generated by two or more light beams, or by using a master hologram. The recording material is formed from a composite material including a polymerized polymer or a polymerized liquid crystal. The periodic structure is formed by exposing the recording material to the interference light to induce the polymerization reaction and phase separation in the composite material.

A grating structure with a dielectric coating is disclosed that operates efficiently away from the blaze angle in low order with a high diffraction efficiency and high wavelength dispersion. Such grating structure can be employed in Littrow configuration to provide, for example, cavity feedback in excimer lasers.

An optical element of which diffraction efficiency hardly varies with wavelength is provided by using an optical material satisfying the conditions that n_d>−6.667×10⁻³v^d+1.70 and θ_g,F≦−2×10⁻³ν_d+0.59 where n_d is a refractive index at d-line, ν_d is an Abbe number at the d-line, and θ_g,F is a second order dispersion at d-line, whereby diffraction efficiency is improved in any working visible wavelength region and more precise chromatic aberration correction is obtained.

A diffractive display system and a method of collecting first order light beams from a diffractive display of the system utilize holographic optical elements (HOEs) to deflect one of two first order diffracted light beams that emerge from each diffracting pixel of the diffractive display, so that the first order diffracted light beams can be separated from the zeroth order light beams. The utilization of the HOEs allows the system to be implemented in a compact optical configuration, without sacrificing any portion of the first order diffracted light. In a first embodiment, the system includes three HOEs that have static diffracting properties that are optimized for red, green and blue lights. For each set of light beams from a diffracting pixel of the diffractive display, the HOEs are holographically configured to deflect only one of the two first order diffracted light beams, such that the deflected first order light beam propagates in the same direction as the other non-deflected first order light beam. In a second embodiment, the system includes three HOEs that have reconfigurable diffracting properties that are also optimized for red, green and blue lights. In a third embodiment, the system further includes a holographic color filter that is comprised of three reconfigurable HOEs to sequentially illuminate the diffractive display with each of the tristimulus color lights.

The invention discloses mask-alignment aligning system and its grade combining system. The aligning system includes light source module, illumination module, imaging module, and detecting module. The grade combining system makes positive negative grade frequency spectrum facula of the alignment mark diffraction spectrum process corresponding overlap coherent, uses polychromatic light separating system to separate multiple wavelength light signal, measures light intensity or phase change at the corresponding position of the multiple wavelength multistage secondary diffracted facula to gain alignment mark position information. The invention has high alignment precision and stability.

A method for the elimination of image speckles in a scanning laser projection is suggested, in which a phase hologram is used for dividing the illumination beam of the projector into partial beams. The partial beams are heterodyned again on the image screen within the image element (pixels) to be projected in such a way that differing speckle patterns are formed which average each other out in the eye of the viewer over time and/or space. Thus, a device is provided especially for the laser projection which substantially eliminates or reduces the speckles at the viewer. However, the beam form and the beam density are hardly or not changed.

An optical apparatus is disclosed by which, even if heat is generated with optical elements in a diffraction grating-optical modulation apparatus, lights emitted from the optical elements is less likely to suffer from displacement therebetween. The optical apparatus includes an optical element, a mounting substrate, a support member, and a cooling/heat radiating member. The support member is attached to a first face of the mounting substrate while the optical element is attached to a second face of the mounting substrate. The cooling/heat radiating member is attached to the support member. The optical element and the support member are thermally connected to each other by a heat transmission element provided in the inside of the mounting substrate. The support member is made of a material having a thermal conductivity of 230 W/m·K or more.

A substrate is subjected to holographic exposure to a sinusoidal or half-sinusoidal resist pattern corresponding to grating groove thereon. Thereafter, the substrate and the resist pattern are subjected to a first etching step at which they are irradiated with an ion beam obliquely at an angle that is identical to the blaze angle in the presence of CF₄ as an etching gas, whereby they are cut until the height of the resist is about ⅓ of the initial value. Thereafter, the substrate is subjected to a second etching step at which the substrate is irradiated with an ion beam in the direction corresponding to the bisector of the vertex in the presence of a mixture of CF₄ and O₂ as an etching gas, whereby the substrate is cut until the resist disappears completely to an extent such that some overetching occurs.

The Holographic Beam Combiner, (HBC), is used to combine the output from many lasers into a single-aperture, diffraction-limited beam. The HBC is based on the storage of multiple holographic gratings in the same spatial location. By using a photopolymer material such as quinone-doped polymethyl methacrylate (PMMA) that uses a novel principle of “polymer with diffusion amplification” (PDA), it is possible to combine a large number (N) of diode lasers, with an output intensity and brightness 0.9 N times as much as those of the combined outputs of individual N lasers. The HBC will be a small, inexpensive to manufacture, and lightweight optical element. The basic idea of the HBC is to construct multiple holograms onto a recording material, with each hologram using a reference beam incident at a different angle, but keeping the object beam at a fixed position. When illuminated by a single read beam at an angle matching one of the reference beams, a diffracted beam is produced in the fixed direction of the object beam. When multiple read beams, matching the multiple reference beams are used simultaneously, all the beams can be made to diffract in the same direction, under certain conditions that depend on the degree of mutual coherence between the input beams.

The backlight for a flat display device including a light source, a light guide plate and a surface hologram is provided. The light guide plate is installed at one side of the light source, and light from the light source travels in the light guide plate while being totally reflected. The surface hologram is formed on at least one surface of the light guide plate. The surface hologram has a pattern of a predetermined grating interval and a predetermined grating depth in order to diffract light at a predetermined angle toward the light guide plate.

The invention discloses a holographic optical waveguide, and belongs to the technical field of augmented reality and virtual reality. The holographic optical waveguide comprises a planar optical waveguide, and an optical coupling in end and an optical coupling out end which are respectively arranged at the two ends of the planar optical waveguide. The optical coupling in end reflects received light rays so that the reflected light rays are enabled to meet the total reflection conditions to be transmitted to the optical coupling out end through multiple times of total reflection between the two reflecting surfaces of the planar optical waveguide. The received light rays are diffractively emergent out of the optical coupling out end. The optical coupling out end is a holographic grating. The holographic grating is a polarization holographic liquid crystal grating comprising a transparent substrate, a light orientation layer and a liquid crystal layer which are arranged in turn, wherein polarization holographic patterns having periodic structures are recorded on the light orientation layer. The invention also discloses a holographic optical waveguide display device. The polarization holographic liquid crystal grating is used as the optical coupling out end of the holographic optical waveguide so that 100% of diffraction efficiency can be achieved theoretically, and zero order waves can be suppressed and conjugate images can be eliminated.

The invention provides a method for manufacturing triangular groove echelon gratings with 90-degree vertex angles. Each triangular groove echelon grating is composed of a silicon grating structure (1), photoresist (3) and a metal film (4). A manufactured grating groove is a triangle with the vertex angle being 90 degrees, so that the diffraction efficiency higher than that of an echelon grating with the vertex angle being not 90 degrees can be achieved. Each grating structure is produced in an obliquely-cut monocrystalline wafer, the shining angles of the gratings are determined by an obliquely-cut angle for cutting each silicon wafer, and gratings with any blazing angles can be manufactured; according to the 90-degree vertex angles, grooves of silicon gratings with the vertex angles being not 90 degrees are filled with photoresist, then photoetching is conducted again, and the original silicon gratings with the vertex angles being not 90 degrees are converted into the triangular groove gratings with the vertex angles being 90 degrees. According to the manufactured grating structure, the shining face of each grating is a smooth monocrystal silicon <111> grate plane, scattering can be effectively lowered, and the diffraction efficiency of each grating is improved. The purpose that all the gratings have high diffraction efficiency on a broadband is achieved according to the fact that using wave bands can choose to be coated with various different reflecting film layers on the surfaces of the gratings.