A privacy display comprises a polarised output spatial light modulator, reflective polariser, plural polar control retarders and a polariser. A birefringent surface relief diffuser structure is arranged to transmit light from the display with high transparency and provide diffuse reflection of ambient light to head-on display users. In a privacy mode of operation, on-axis light from the spatial light modulator is directed without loss and with low diffusion, whereas off-axis light has reduced luminance and increased diffusion. Further, overall display reflectivity is reduced for on-axis reflections of ambient light, while reflectivity is increased for off-axis light. The visibility of the display to off-axis snoopers is reduced by means of luminance reduction, increased frontal reflectivity and diffusion of ambient light. In a public mode of operation, the liquid crystal retardance is adjusted so that off-axis luminance and reflectivity are unmodified.

Disclosed is an optical assembly having a first variable transmission layer comprising a first electro-optically active material between a first pair of substrates, a second variable transmission layer comprising a second electro-optically active material between a second pair of substrates, and an electronically switchable birefringent layer, that is capable of altering the phase of incident light, situated between the first and second variable transmission layers. The layers are arranged such that light passing through the optical assembly can be altered based on the voltage applied to each layer. The light transmission levels can be altered between maximally transmissive, minimally transmissive, and semi-transparent levels between the maximally and minimally transmissive levels.

Disclosed is an optical assembly having a first variable transmission layer comprising a first electro-optically active material between a first pair of substrates, a second variable transmission layer comprising a second electro-optically active material between a second pair of substrates, and an electronically switchable birefringent layer, that is capable of altering the phase of incident light, situated between the first and second variable transmission layers. The layers are arranged such that light passing through the optical assembly can be altered based on the voltage applied to each layer. The light transmission levels can be altered between maximally transmissive, minimally transmissive, and semi-transparent levels between the maximally and minimally transmissive levels.

Optical film stacks are described. More particularly, optical film stacks including a half-wave retardation layer are described. Achromatic half-wave retardation layers, including achromatic half-wave layers formed from a quarter-wave and a three-quarters-wave retardation layer, are described. Film stacks including reflective polarizers tuned to reduce wavelength dispersion of the half-wave retardation layer are also described.

Optical film stacks are described. More particularly, optical film stacks including a half-wave retardation layer are described. Achromatic half-wave retardation layers, including achromatic half-wave layers formed from a quarter-wave and a three-quarters-wave retardation layer, are described. Film stacks including reflective polarizers tuned to reduce wavelength dispersion of the half-wave retardation layer are also described.

Systems and methods are disclosed for selectively allowing or preventing output of laser pulses. In some embodiments, a laser system comprises a shutter and a shutter motor. The shutter motor is configured to move the shutter in an alternating manner between a first position in which output of laser electromagnetic radiation is allowed a second position in which output of laser electromagnetic radiation is prevented.

A touch element includes a polymer phase retardation layer and a touch sensing structure. The polymer phase retardation layer receives the linearly polarized incident light and then produces a phase difference. The touch sensing structure is disposed on the polymer phase retardation layer.

A touch element includes a polymer phase retardation layer and a touch sensing structure. The polymer phase retardation layer receives the linearly polarized incident light and then produces a phase difference. The touch sensing structure is disposed on the polymer phase retardation layer.

Disclosed is a polymerizable liquid crystal material wherein an amount of a salt represented by the following formula (I) is less than 0.01 parts by mass per 100 parts by mass of a polymerizable liquid crystal compound, and an amount of a nitrogen-containing compound represented by the following formula (II) is 0.01 parts by mass or less per 100 parts by mass of the polymerizable liquid crystal compound. R.sup.1 to R.sup.5 each independently represent a hydrogen atom or a C1-C7 alkyl group, R.sup.6 and R.sup.7 represents a hydrogen atom, and X represents F.sup.−, Br.sup.−, Cl.sup.−, I.sup.−, HSO.sub.4.sup.−, 1/2(HPO.sub.4.sup.2−), H.sub.2PO.sub.4.sup.−, R—C(═O)—O.sup.−, 1/2(.sup.−O—(C═O)—R′—(C═O)—O.sup.−) or R—SO.sub.3.sup.−, where R represents a hydrogen atom or a monovalent hydrocarbon group, and R′ represents a single bond or a divalent hydrocarbon group. ##STR00001##

A phase delay device, its preparation method and a display equipment are provided. The phase delay device includes linear polarization layer, alignment layer and liquid crystal layer. The linear polarization layer is configured to convert received light into a linear polarization light; the alignment layer is configured to align liquid crystals of a first subpart of the liquid crystal layer based on a preset alignment angle; the liquid crystal layer is located at a side of the alignment layer away from the linear polarization layer, and includes a first subpart adjacent to the alignment layer, a second subpart having a spiral structure with a preset spiral angle and a third subpart; a liquid crystal alignment angle of the third subpart is determined based on the preset alignment angle and the preset spiral angle; birefringence of the liquid crystal layer does not decrease with an increase of visible light wavelength.