Display with active contrast enhancement

A display comprising:

• an image-producing component having a multiplicity of imaging lines for producing an image, each imaging line being regularly updated to provide light that produces part of the image, largely all of each such image part being displayed largely simultaneously at any time when that image part is being displayed;
• and
• a set of shutter strips, each (a) associated with at least one of the imaging lines, (b) situated in front of each so-associated imaging line outside the image-producing component, and (c) being switched during operation of the display between a light-transmissive state and a light-absorptive state such that each shutter strip is in its light-transmissive state at least partly while each imaging line associated with that strip is providing light for creating the image, the shutter strips constituting parts of a liquid-crystal structure in which liquid-crystal material comprises host cholesteric liquid crystal and guest black dichroic dye, part of the liquid-crystal material being present in each shutter strip and, when that shutter strip is in its light-absorptive state, having a cholesteric twist whose twist pitch is no more than 5 μm.

A method comprising the steps of:

• producing an image by regularly updating each of a multiplicity of imaging lines of an image-producing flat-panel component to provide light that produces part of the image;
• and
• switching each of a set of shutter strips, each associated with at least one of the imaging lines and being situated in front of each so-associated imaging line outside the image-producing component, between a light-transmissive state and a light-absorptive state such that each shutter strip is in its light-transmissive state at least partly while each imaging line associated with that strip is providing light for creating the image, the shutter strips constituting parts of a liquid-crystal structure in which liquid-crystal material comprises host cholesteric liquid crystal and guest black dichroic dye, part of the liquid-crystal material being present in each shutter strip and, when that shutter strip is in its light-absorptive state, having a cholesteric twist whose twist pitch is no more than 5 μm.