US 11,886,083 B2Granted

Diffraction free color mask

OwnerSteen Svendstorp Krener-Iverseninventor

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Abstract

A monochrome display is converted into a color display by including an electrically controllable planar color filter plate switchable between primary colors and operating the display in a color field sequential mode. Hence the requirement for a color switchable illumination source is eliminated. For example the illumination source may be a white OLED, an illumination type which, in combination with a microlens array, has proven well suited for directional displays. Further the need for a color mask is eliminated, thereby eliminating problems of moiree interference with a microlens array and further eliminating problems of diffraction patterns in infrared images captured through the display for example for observer tracking purposes. The electrically controllable planar color filter plate may comprise two wavelength dependent wave retarders and two liquid crystal cells.

Claims33

Dependent claims

A display for directional control of an image to an observer, said display comprising:

a plurality of image pixels,
each image pixel defining an area having a plurality of subpixels,
each subpixel being addressable for emitting light in a direction towards said observer,
each pixel comprising
a thin film stack of an electroluminescent layer for generating substantially white light,
a color filter for transmitting a first wavelength or wavelength range of said substantially white light in a first time interval and a second wavelength or wavelength range substantially of said white light in a second time interval such that a color perceived by said observer being a combination of said first wavelength or wavelength range and said second wavelength or wavelength range,
an optical element for focusing light from a sub pixel of said plurality of subpixels,
said optical element having a focal point between said optical element and a point in front of and infinitely far away from said optical element,
said optical element having a diameter greater than 30% of an image pixel pitch, and said display comprising a single optical element per image pixel.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 17/439,007Filed 16 Mar 2020
Priority: EP 1916328315 Mar 2019
Published: US 2022/0146876 A112 May 2022
Granted: 30 Jan 2024
Term ends: Not estimatedThe source records don’t support an estimate.

Classification16 codes

G02B 30/29
Involving lenticular arrays: characterised by the geometry of the lenticular array, e.g. slanted arrays, irregular arrays or arrays of varying…
G02F 1/133526
Structural association of cells with optical devices, e.g. polarisers or reflectors: lenses, e.g. microlenses or Fresnel lenses
G02F 1/133607
Including a specially adapted diffusing, scattering or light controlling members: the light controlling member including light directing or…
G02F 1/13473
In which all the liquid crystal cells or layers remain transparent, e.g. FLC, ECB, DAP, HAN, TN, STN, SBE-LC cells: for wavelength filtering or…