Display devices using feedback-enhanced light emitting diodes are disclosed. The display devices include but are not limited to active and passive matrix displays and projection displays. A light emissive element disposed between feedback elements is used as light emitting element in the display devices. The light emissive element may include organic or non-organic material. The feedback elements coupled to an emissive element allow the emissive element to emit collimated light by stimulated emission. In one aspect, feedback elements that provide this function include, but are not limited to, holographic reflectors with refractive index variations that are continuous.

A method of manufacturing a security feature for identifying objects or documents of value. The method may include the steps of encoding information in a pattern; and ink jet printing a chiral nematic liquid crystal material from a reservoir using a print head on to a substrate in the pattern. Thus, the method forms a patterned array of chiral nematic liquid crystal material deposits. The print head, or the reservoir, or both, may be heated to a temperature above the clearing point of the chiral nematic liquid crystal material. The chiral axes of the chiral nematic liquid crystal material deposits may be aligned substantially perpendicular to the substrate such that a predetermined portion of the electromagnetic spectrum is selectively reflected over other regions of the electromagnetic spectrum by the chiral nematic liquid crystal material deposits.

Provided is a laser oscillation element including a cholesteric liquid crystal layer, in which even in a case where the intensity of excitation light is weak, laser oscillation can be induced. The laser oscillation element includes a cholesteric liquid crystal layer obtained by cholesteric alignment of a liquid crystal compound, in which in a cross-section of the cholesteric liquid crystal layer observed with a scanning electron microscope, bright portions and dark portions derived from the cholesteric liquid crystalline phase are tilted with respect to a main surface of the cholesteric liquid crystal layer, the cholesteric liquid crystal layer includes a colorant that emits light by excitation, and a luminescence wavelength range of the colorant and a selective reflection wavelength range of the cholesteric liquid crystal layer at least partially overlap each other.

The present invention relates to a method, system and device for transmitting information from an optical communication transmitter to a receiving station via a laser beam and for alignment of said laser beam emitted from said optical communication transmitter with said receiving station, wherein: said optical communication transmitter is displaced relative to said receiving station and comprises a laser, a radio receiver, a microprocessor and a liquid crystal on silicon spatial light modulator comprising a diffractive element, whereby said laser beam is emitted from said laser and is projected over an area by diffraction and reflection using said liquid crystal on silicon spatial light modulator, wherein said laser and said diffractive element are controlled by said microprocessor, wherein said laser beam has a longitudinal axis parallel to the propagation path of said laser beam, said receiving station comprises a photodiode receiver for detecting said transmitted laser beam and a radio transmitter, and said method comprises using a pointing diffraction mask and a tracking diffraction mask, wherein each pointing diffraction mask is generated in combination with a tracking diffraction mask in said diffractive element.