Abstract: In an optical display system that includes a waveguide with multiple diffractive optical elements (DOEs), gratings in one or more of the DOEs may have an asymmetric profile in which gratings may be slanted or blazed. Asymmetric gratings in a DOE can provide increased display uniformity in the optical display system by reducing the “banding” resulting from optical interference that is manifested as dark stripes in the display. Banding may be more pronounced when polymeric materials are used in volume production of the DOEs to minimize system weight, but which have less optimal optical properties compared with other materials such as glass. The asymmetric gratings can further enable the optical system to be more tolerant to variations—such as variations in thickness, surface roughness, and grating geometry—that may not be readily controlled during manufacturing particularly since such variations are in the submicron range.

Abstract: In an optical display system that includes a waveguide with multiple diffractive optical elements (DOEs), gratings in one or more of the DOEs may have an asymmetric profile in which gratings may be slanted or blazed. Asymmetric gratings in a DOE can provide increased display uniformity in the optical display system by reducing the “banding” resulting from optical interference that is manifested as dark stripes in the display. Banding may be more pronounced when polymeric materials are used in volume production of the DOEs to minimize system weight, but which have less optimal optical properties compared with other materials such as glass. The asymmetric gratings can further enable the optical system to be more tolerant to variations—such as variations in thickness, surface roughness, and grating geometry—that may not be readily controlled during manufacturing particularly since such variations are in the submicron range.

Abstract: In an optical display system that includes a waveguide with multiple diffractive optical elements (DOEs), gratings in one or more of the DOEs may have an asymmetric profile in which gratings may be slanted or blazed. Asymmetric gratings in a DOE can provide increased display uniformity in the optical display system by reducing the “banding” resulting from optical interference that is manifested as dark stripes in the display. Banding may be more pronounced when polymeric materials are used in volume production of the DOEs to minimize system weight, but which have less optimal optical properties compared with other materials such as glass. The asymmetric gratings can further enable the optical system to be more tolerant to variations—such as variations in thickness, surface roughness, and grating geometry—that may not be readily controlled during manufacturing particularly since such variations are in the submicron range.

Abstract: In an optical system that includes a waveguide with multiple diffractive optical elements (DOEs) incorporating diffraction gratings, light exiting a trailing edge of an upstream DOE enters a leading edge of a downstream DOE. One or more of the DOEs may include a leading and/or a trailing edge that have a graded profile. At a graded trailing edge of an upstream DOE, grating height smoothly decreases from full height to shallow height as a function of the proximity to the trailing edge. At a graded leading edge of the downstream DOE grating height smoothly increases from shallow height to full height as a function of distance away from the leading edge. By reducing a sharp boundary at the interface between the upstream and downstream DOEs, the graded profiles of the DOE edges enable optical resolution to be maintained decreasing sensitivity to misalignment between the DOEs that may occur during manufacturing.

Abstract: In an optical display system that includes a waveguide with multiple diffractive optical elements (DOEs), one or more of the DOEs is configured with gratings that have varying depth and varying directions for depth modulation, in which the modulation direction is aligned with the steepest change (i.e., slope) of grating depth. Depth modulation direction may change at a point of transition between different regions in the DOE. For example, with a zero axis being defined along a line parallel to a long side of a DOE, the depth modulation direction can change from a negative angle, with respect to the axis in the plane of the waveguide in one region, to a positive angle in another region, or vice versa. By varying depth modulation direction in a DOE, display uniformity in the optical display system may be increased.

Abstract: In an optical display system that includes a waveguide with multiple diffractive optical elements (DOEs), one or more of the DOEs is configured with gratings that have varying depth and varying directions for depth modulation, in which the modulation direction is aligned with the steepest change (i.e., slope) of grating depth. Depth modulation direction may change at a point of transition between different regions in the DOE. For example, with a zero axis being defined along a line parallel to a long side of a DOE, the depth modulation direction can change from a negative angle, with respect to the axis in the plane of the waveguide in one region, to a positive angle in another region, or vice versa. By varying depth modulation direction in a DOE, display uniformity in the optical display system may be increased.

Abstract: In an optical display system that includes a waveguide with multiple diffractive optical elements (DOEs), gratings in one or more of the DOEs may have an asymmetric profile in which gratings may be slanted or blazed. Asymmetric gratings in a DOE can provide increased display uniformity in the optical display system by reducing the “banding” resulting from optical interference that is manifested as dark stripes in the display. Banding may be more pronounced when polymeric materials are used in volume production of the DOEs to minimize system weight, but which have less optimal optical properties compared with other materials such as glass. The asymmetric gratings can further enable the optical system to be more tolerant to variations—such as variations in thickness, surface roughness, and grating geometry—that may not be readily controlled during manufacturing particularly since such variations are in the submicron range.

Abstract: In an optical system that includes a waveguide with multiple diffractive optical elements (DOEs) incorporating diffraction gratings, light exiting a trailing edge of an upstream DOE enters a leading edge of a downstream DOE. One or more of the DOEs may include a leading and/or a trailing edge that have a graded profile. At a graded trailing edge of an upstream DOE, grating height smoothly decreases from full height to shallow height as a function of the proximity to the trailing edge. At a graded leading edge of the downstream DOE grating height smoothly increases from shallow height to full height as a function of distance away from the leading edge. By reducing a sharp boundary at the interface between the upstream and downstream DOEs, the graded profiles of the DOE edges enable optical resolution to be maintained decreasing sensitivity to misalignment between the DOEs that may occur during manufacturing.

Abstract: A display system comprises an optical waveguide and a light engine. The light engine generates multiple input beams which form a virtual image. An incoupling grating of the optical waveguide couples each beam into an intermediate grating of the waveguide, in which that beam is guided onto multiple splitting regions. The intermediate grating splits that beam at the splitting regions to provide multiple substantially parallel versions of that beam. Those multiple versions are coupled into an exit grating of the waveguide, in which the multiple versions are guided onto multiple exit regions. The exit grating diffracts the multiple versions of that beam outwardly. The multiple input beams thus cause multiple exit beams to exit the waveguide which form a version of the virtual image. The incoupling and intermediate gratings are substantially contiguous, separated by no more than 100 micrometres in width along a common border.

Abstract: Microfabrication processes and apparatuses for fabricating microstructures on a substrate are disclosed. The substrate has a current diffraction grating pattern formed by current surface modulations over at least a portion of the substrate's surface that exhibit a substantially uniform grating linewidth over the surface portion. An immersion depth of the substrate in a fluid for patterning the substrate is gradually changed so that different points on the surface portion are immersed for different immersion times. The fluid changes the linewidth of the surface modulations at each immersed point on the surface portion by an amount determined by the immersion time of that point, thereby changing the current diffraction grating pattern to a new diffraction grating pattern formed by new surface modulations over the surface portion that exhibit a spatially varying grating linewidth that varies over the surface portion.

Abstract: A microfabrication apparatus for fabricating a microstructure on a substrate is disclosed and comprises a partitioning system arranged to provide an aperture, a particle source that can generate a beam of particles for patterning the substrate and a substrate holder which supports the substrate. Relative motion is effected between the aperture and the substrate over a portion of the substrate's surface so that different points on the surface portion are exposed at different times. Whilst that motion is ongoing, one or more exposure conditions are varied so that the different points are subject to different exposure conditions. Corresponding microfabrication processes and products obtained thereby are also disclosed.

Abstract: Various optical components are disclosed herein, which have diffraction gratings formed by modulations of at least portions of their outer surfaces. The gratings exhibit gradually varying characteristics that vary over the surface portion so as to gradually vary the manner in which the incident light is diffracted at different points on the surface portion. Display systems incorporating such optical components are also disclosed.

Abstract: Microfabrication processes and apparatuses for fabricating microstructures on a substrate are disclosed. The substrate has a current diffraction grating pattern formed by current surface modulations over at least a portion of the substrate's surface that exhibit a substantially uniform grating linewidth over the surface portion. An immersion depth of the substrate in a fluid for patterning the substrate is gradually changed so that different points on the surface portion are immersed for different immersion times. The fluid changes the linewidth of the surface modulations at each immersed point on the surface portion by an amount determined by the immersion time of that point, thereby changing the current diffraction grating pattern to a new diffraction grating pattern formed by new surface modulations over the surface portion that exhibit a spatially varying grating linewidth that varies over the surface portion.

Abstract: The invention relates to an electrospray ionization (ESI) device for forming a stream of ionized sample molecules. The device comprises a sample introduction zone for receiving a liquid-form sample, a tip for spraying the sample into aerosol or gaseous form, and a flow channel connecting the sample introduction zone and the tip. According to the invention, the flow channel comprises an array of transversely oriented microstructures adapted to passively transport the liquid-form sample introduced to the sample introduction zone to the tip by means of capillary forces. The invention concerns also a manufacturing method and applications of the ESI device, in particular mass spectrometry. The device can be used without external pumping of sample liquid.

Abstract: The invention relates to an electrospray ionization (ESI) device for forming a stream of ionized sample molecules. The device comprises a sample introduction zone for receiving a liquid-form sample, a tip for spraying the sample into aerosol or gaseous form, and a flow channel connecting the sample introduction zone and the tip. According to the invention, the flow channel comprises an array of transversely oriented microstructures adapted to passively transport the liquid-form sample introduced to the sample introduction zone to the tip by means of capillary forces. The invention concerns also a manufacturing method and applications of the ESI device, in particular mass spectrometry. The device can be used without external pumping of sample liquid.