Abstract: The invention relates to a waveguide display element comprising a waveguide body and an in-coupling grating (21) arranged to the waveguide body. The in-coupling grating (21) is configured to couple incoming light into the waveguide body into two separate directions (26A, 26B) using opposite diffraction orders (IC:+1, IC:?1) for splitting the field of view of the incoming light. Further the in-coupling grating (21) is configured, typically by setting its period suitably short, such that said coupling takes place only at wavelengths below a threshold wavelength residing in the visible wavelength range. The invention also relates to a waveguide stack (51 A, 51 B, 51 C).

Abstract: The invention relates to a diffractive waveguide display element comprising a waveguide body (13) having a first surface and a second surface opposite to the first surface, an outcoupling-diffractive optical element on said first surface for coupling light propagating inside the waveguide body out of the waveguide body, and a narrow-band reflector element (21) on said second surface. The invention also relates to a display device comprising such element.

Abstract: The invention relates to a laser projector for presenting an image on a waveguide plane. The projector comprises a laser source (10, 10A, 10B, 10C) capable of emitting a polychromatic light beam (11) or a plurality of narrow-wavelength light beams (11A, 11B, 11C), and a guidance element (12A, 12B) for directing light emitted by the light source to different pupils (16A, 16B, 16C) of the waveguide plane, the different pupils being displaced with respect to each other in the waveguide plane. The invention also concerns a personal display device comprising such projector.

Abstract: There is provided an exit pupil expander (EPE) for use in a diffractive display, the EPE comprising a plurality of diffractive zones on a waveguide and a plurality of non-diffractive zones between at least some of the diffractive zones.

Abstract: The invention relates to a waveguide display element (20) comprising a waveguide comprising at least three waveguide N layers (14A-14C) stacked on top of each other. There is also provided diffractive in-coupling gratings (16A-16C) associated with each waveguide layer (14A-14C) and being displaced with respect to each other in the plane of the layers, the in-coupling gratings (16A-16C) forming input pupils for different light wavelength ranges (13A-13C) coupled to the waveguide, and a diffractive out-coupling means (18) for coupling light in-coupled through the pupils and propagating in the layers out of the waveguide such that a polychromatic image is formed. The invention also concerns a personal display device comprising such element.

Abstract: The invention relates to a diffractive waveguide display device comprising an image projector capable of emitting laser rays at one or more wavelengths, a waveguide body having a first surface and an opposite second surface and adapted to guide said laser rays from the image projector between the first surface and the second surface, an out-coupling diffractive optical element on said first surface for coupling said laser rays out of the waveguide body, and an anti-interference coating (35) arranged on the second surface of the waveguide body aligned with the out-coupling diffractive optical element.

Abstract: A diffractive waveguide element for a personal display device includes a display waveguide extending in a waveguide plane, an in-coupling diffractive optical element arranged onto or into the display waveguide for diffractively coupling light rays into the display waveguide, and an out-coupling diffractive optical element arranged onto or into the display waveguide for coupling the diffractively coupled light rays out of the display waveguide. In addition, there is provided a ray multiplier element optically upstream of the out-coupling diffractive optical element, the ray multiplier element being capable of splitting a light ray incoming to the in-coupling grating into a plurality of parallel rays spatially displaced in the waveguide plane before they enter the out-coupling diffractive optical element. A waveguide display device is also provided.

Abstract: The invention provides the present invention provides a faecal detection sensor for an absorbent article. The sensor includes a faeces-sensitive material that reacts to the presence of a constituent of faecal matter, wherein the sensor exhibits an electrical property that changes following the reaction of the faeces-sensitive material. In embodiments of the invention the faeces sensitive material is a material that reacts due to the presence of a sulfur-containing compound in faecal matter, such as metallic faeces-sensitive materials, or is a material that reacts with a faecal enzyme and/or other constituents of faecal matter, such as organic faeces-sensitive materials.

Abstract: The invention relates to a diffractive optical grating and applications thereof. The grating comprises a first zone and a second zone each having a two-dimensionally periodic grating structure having a first period (dx) in a first direction, the first period being chosen to allow for diffraction of selected wavelengths of visible light along the first direction, and a second period (dy) in a second direction different from the first direction, the second period (dy) being short enough to prevent diffraction of said selected wavelengths along the second direction. According to the invention, the grating structures in the first zone and in the second zone have different modulation characteristics in said second direction for producing different diffraction efficiencies for the first and second zones. The invention provides a new design parameter, sub-wavelength modulation, for assisting in local adjustment of diffraction efficiency of gratings in particular in display applications.

Abstract: The invention conerns a display element for a personal display system, a personal display, a method and a use. The display element comprises a lightguide capable of guiding light by total internal reflections, a diffractive in-coupling grating, and a diffractive out-coupling grating. The in-coupling grating is adapted to couple light directed thereto to the lightguide so as to allow propagation of the light to the out-coupling grating. According to the invention, the in-coupling grating is adapted to couple light to the lightguide as at least two diffraction wavefronts and the display element further comprises at least two different exit pupil expander gratings adapted to guide said wavefronts respectively to the out-coupling grating along different paths. The invention allows for reducing the size of diffractive display elements.

Abstract: The invention concerns a multi-pupil lightguide element, a diffractive personal display, multi-pupil projector, a method for displaying an image and a use. The element comprises lightguide means, diffractive in-coupling means for coupling an image directed to the in-coupling means into the lightguide means, and diffractive out-coupling means for coupling said image out of the lightguide means. According to the invention, the diffractive in-coupling means comprise at least two in-coupling gratings laterally displaced from each other on said lightguide means for receiving segments of said image, and the diffractive out-coupling means is optically associated with said at least two in-coupling gratings for reproducing said image from said image segments. The invention allows for expanding the field-of-view of near-to-eye displays, for example.

Abstract: An optical see-through display element and a display device using such an element. The element having a transparent substrate including two opposite faces, an in-coupling structure for coupling light into the substrate, and a diffractive out-coupling grating structure arranged on the transparent substrate for displaying the in-coupled light on the transparent substrate. The diffractive out-coupling structure includes at least two multi-layer gratings superimposed on top of each other on at least one of said opposite faces of the substrate. In particular, multilayer gratings reducing diffraction of transmissive light can be used. The element and device help to increase the out-coupling efficiency of diffractive displays and provides also technology to simultaneously maintain high image quality and transparency.

Abstract: The invention relates to an optical see-through display element and a display device using such element. The element comprises a transparent substrate comprising two opposite faces, an in-coupling structure for coupling light into the substrate, and a diffractive out-coupling grating structure arranged on the transparent substrate for displaying the in-coupled light on the transparent substrate. According to the invention, the diffractive out-coupling structure comprises at least two multi-layer gratings superimposed on top of each other on at least one of said opposite faces of the substrate. In particular, multilayer gratings reducing diffraction of transmissive light can be used. The invention helps to increase the out-coupling efficiency of diffractive displays and provides also technology to simultaneously maintain high image quality and transparency.

Abstract: The invention relates to optical devices comprising a transparent substrate and a first transparent grating layer on the substrate, the grating layer comprising periodically alternating zones having different refractive indices. According to the invention, the device comprises a second transparent grating layer located on top of the first grating layer and also comprising periodically alternating zones having different refractive indices so that the zones of the first grating layer having higher refractive index are at least partly aligned with the zones of the second grating layer having lower refractive index and vice versa, the second grating layer reducing the amount of light diffracted to non-zero transmission orders. The invention allows for reducing the so-called rainbow effect for example in head-up displays (HUDs).

Abstract: The invention relates to a method for manufacturing liquid- guiding structural layers by flexo or gravure printing on a substrate sheet, using a printing solution, which alters the properties of the substrate sheet in such a way that liquid flow is prevented in the area of the structural layers. The penetrability of the printing layer into the substrate sheet can be regulated by the printing-cylinder pressure and the composition of the printing solution. In the method it is possible to use printing solutions consisting of economical polymers and a solvent. In terms of printing technology, the invention is compatible with existing printing machines and is thus highly suitable for mass production.

Abstract: The invention relates to optical devices comprising a transparent substrate and a first transparent grating layer on the substrate, the grating layer comprising periodically alternating zones having different refractive indices. According to the invention, the device comprises a second transparent grating layer located on top of the first grating layer and also comprising periodically alternating zones having different refractive indices so that the zones of the first grating layer having higher refractive index are at least partly aligned with the zones of the second grating layer having lower refractive index and vice versa, the second grating layer reducing the amount of light diffracted to non-zero transmission orders. The invention allows for reducing the so-called rainbow effect for example in head-up displays (HUDs).

Abstract: The invention relates to a method for manufacturing liquid- guiding structural layers by flexo or gravure printing on a substrate sheet, using a printing solution, which alters the properties of the substrate sheet in such a way that liquid flow is prevented in the area of the structural layers. The penetrability of the printing layer into the substrate sheet can be regulated by the printing-cylinder pressure and the composition of the printing solution. In the method it is possible to use printing solutions consisting of economical polymers and a solvent. In terms of printing technology, the invention is compatible with existing printing machines and is thus highly suitable for mass production.