Abstract: An image combiner for a viewing device, such as a night vision device, is disclosed for combining a first image, such as generated symbology, with a second image, such as a view of an outside scene in reduced lighting conditions. A waveguide is provided for capturing the first image from a first viewing direction, and for directing the first image in a second viewing direction, the second viewing direction being substantially coincident with a viewing direction of the second image, such that the first image can combine with the second image. At least a portion of the waveguide is arranged to substantially transmit the second image, such that the second image can pass substantially through the waveguide.

Abstract: An image-providing light source device 58 is arranged to inject a non-coherent and collimated image into waveguide element 60. Light forming the image is dispersed by an optical element 76 so as to occupy a continuum of angles within the waveguide 60. The optical element 76 and a grating 70 are arranged such that the light exiting the waveguide occupies a single angle. Thereby, pupil banding of light exiting the waveguide 60 is mitigated.

Abstract: The present invention provides a projection display (10) for projecting a color image to a viewer (12) overlaid on a real world scene viewed through the display. The display comprises an image generator (16) for generating image bearing chromatic light for injection into a waveguide assembly (28) at a first range of field angles (44) and a second range of field angles (46). The waveguide assembly comprises a first waveguide (30) having a first input diffraction region (32) arranged to couple image bearing chromatic light in the first range of field angles into the first waveguide to propagate by total internal reflection; and a second waveguide (40) having a second input diffraction region (42) arranged to couple image bearing chromatic light in the second range of field angles into the second waveguide to propagate by total internal reflection.

Abstract: An optical waveguide comprising a body of material configured for the contained propagation of light therethrough, a surface relief grating configured to receive the propagating light and at least partially to diffract or reflect it out of the waveguide, and at least one layer of dielectric material of varying thickness having a first surface and a second surface which conforms to a profiled surface of the grating so that the grating exhibits a spatial variation in efficiency dependent on the varying thickness of the dielectric material.

Abstract: An optical waveguide (2) arranged to transmit light under total internal reflection has a first diffractive grating region (8) arranged to receive light and diffract the received light along the optical waveguide (2), an intermediate diffraction grating (10) optically coupled to the first diffractive grating region (8) arranged to expand received light in a first dimension and a second diffractive grating region (9) optically coupled to the intermediate diffraction grating (10) arranged to expand light in a second dimension, orthogonal to the first dimension and to output the light expanded in the first and second dimensions from the optical waveguide (2) by diffraction. The first and second diffractive grating regions (8,9) are fabricated as a common grating whereas the second grating is fabricated above the common grating in an area where the common grating is erased by a coating.

Abstract: A projection display is provided including a first plate-like waveguide (7), an image providing light source device (10 and 11) located to inject image bearing light into the first plate-like waveguide 7. An input means (12) is provided on the waveguide (7) to reflect the image bearing light internally along the waveguide (7). A transmission grating (13) within the first plate-like waveguide (7) is provided to output image bearing light from the waveguide (7). A second plate-like waveguide (8) is located co-planar with the first plate-like waveguide (7) and has a coupling grating (17) therein to receive the image bearing light from the first plate-like waveguide (7). The second plate-like waveguide (8) also includes an exit grating (18) therein for diffracting the received image bearing light, diffracted by the coupling grating (17) out of the second plate-like waveguide (8) towards a viewer (6).

Abstract: An optical waveguide (2) arranged to transmit light under total internal reflection has a first diffractive grating region (8) arranged to receive light and diffract the received light along the optical waveguide (2), an intermediate diffraction grating (10) optically coupled to the first diffractive grating region (8) arranged to expand received light in a first dimension and a second diffractive grating region (9) optically coupled to the intermediate diffraction grating (10) arranged to expand light in a second dimension, orthogonal to the first dimension and to output the light expanded in the first and second dimensions from the optical waveguide (2) by diffraction. The first and second diffractive grating regions (8,9) are fabricated as a common grating whereas the second grating is fabricated above the common grating in an area where the common grating is erased by a coating.

Abstract: A projection display 210 arranged to display an image to an observer 212 use waveguide techniques to generate a display defining a large exit pupil at the point of the observer 212 and a large field of view, while using a small image-providing light source device. The projection display 210 uses two parallel waveguides 214, 216 made from a light transmissive material. One waveguide 214 stretches the horizontal pupil of the final display and the other waveguide 216 stretches the vertical pupil of the final display and acts as a combiner through which the observer 212 views an outside world scene 220 and the image overlaid on the scene 220. In a color display, each primary color is transmitted within a separate channel R, G, B.

Abstract: A helmet or head-mounted apparatus has a visor or other curved optical element in front of at least one eye of a wearer, which element also is used as a waveguide. Image-bearing light is injected into the waveguide via an input diffractive element, and propagates through the visor to an output diffractive element which releases the light. The optical powers of the curved waveguide and the input and output diffractive elements are selected so that the released light is delivered as an image to the users eye.

Abstract: In present invention provides a micro-display device having a source of illumination comprising an array of illuminating portions and an image generator arranged for receiving a signal comprising image data and comprising an array of image forming portions which may be selectively activated to project image-bearing light corresponding with the image data when illuminated by light from the source of illumination. A controller is also provided, arranged for receiving the image data and for selectively activating illuminating portions of the array of illuminating portions according to the image data and according to predetermined criteria relating to heat generation or power consumption by the micro-display device.

Abstract: The present invention relates to a projection display (10) for displaying an image to a viewer, comprising a curved waveguide (14) made of light transmissive material and having first and second opposed curvilinear surfaces (26, 28), an image-providing light source device arranged to inject collimated image bearing light into the waveguide, an input grating (20) coupled to or within the waveguide to diffract said image bearing light to propagate internally along the curved waveguide by total internal reflection, an output grating (22) provided along a side of the waveguide by which the image bearing light is diffracted out of the waveguide for viewing by the viewer, wherein the input grating and output grating have variable pitch gratings so that a collimated image injected into the waveguide can be output from the waveguide as a collimated image having an increased exit pupil.

Abstract: The present invention provides a projection display (10) for projecting a colour image to a viewer (12) overlaid on a real world scene viewed through the display. The display comprises an image generator (16) for generating image bearing chromatic light for injection into a waveguide assembly (28) at a first range of field angles (44) and a second range of field angles (46). The waveguide assembly comprises a first waveguide (30) having a first input diffraction region (32) arranged to couple image bearing chromatic light in the first range of field angles into the first waveguide to propagate by total internal reflection; and a second waveguide (40) having a second input diffraction region (42) arranged to couple image bearing chromatic light in the second range of field angles into the second waveguide to propagate by total internal reflection.

Abstract: A waveguide 112 includes a substrate of material 134 having optical layers 148, 152 applied to two external surfaces 146, 150. This reduces the critical angle c5 of the substrate of material 134 to provide greater interaction between image bearing light following a light path 140 and a grating element 142 and/or a greater total field of view 160, when compared to the total field of view 132 of a prior art waveguide 110, that is capable of being transmitted by the waveguide 112. Such a waveguide 112 can be used in a projection display.

Abstract: In a slab waveguide which expands an image-bearing pupil into a visible image, reflective edge surfaces are used to redirect once-diffracted light back through the same grating structure. The number of separate grating structures thereby can be reduced to two or even one, compared to three in the prior art.

Abstract: An image combiner for a viewing device, such as a night vision device, is disclosed for combining a first image, such as generated symbology, with a second image, such as a view of an outside scene in reduced lighting conditions. A waveguide is provided for capturing the first image from a first viewing direction, and for directing the first image in a second viewing direction, the second viewing direction being substantially coincident with a viewing direction of the second image, such that the first image can combine with the second image. At least a portion of the waveguide is arranged to substantially transmit the second image, such that the second image can pass substantially through the waveguide.

Abstract: An optical method of displaying an expanded colour image comprising extracting from input light bearing said coloured image a first spectral portion and a second spectral portion such that together the two portions contain sufficient information for the image to be displayed in substantially its original colours, separately expanding the two spectral portions each in two dimensions and recombining the expanded spectral portions to display the expanded colour image.

Abstract: A primary waveguide and a coupling waveguide are arranged so a user can view light from a forward scene through the primary waveguide. An image source generates an image which is diffractively coupled into the primary waveguide and internally reflected to an exit area for diffraction towards the user. Light from the forward looking scene is diffracted into the primary waveguide to be internally reflected and coupled to a image intensifier tube assembly. The image intensifier tube assembly enhances light from the forward looking scene and drives the image source such that an image of the enhanced light is overlaid on light from a forward scene at exit area.

Abstract: The present invention relates to a projection display (10) for displaying an image to a viewer, comprising a curved waveguide (14) made of light transmissive material and having first and second opposed curvilinear surfaces (26, 28), an image-providing light source device arranged to inject collimated image bearing light into the waveguide, an input grating (20) coupled to or within the waveguide to diffract said image bearing light to propagate internally along the curved waveguide by total internal reflection, an output grating (22) provided along a side of the waveguide by which the image bearing light is diffracted out of the waveguide for viewing by the viewer, wherein the input grating and output grating have variable pitch gratings so that a collimated image injected into the waveguide can be output from the waveguide as a collimated image having an increased exit pupil.

Abstract: The invention relates to a display device for displaying an image over a field of view. The device comprises: an optical arrangement for directing image bearing light from an image source so that the light has rays at a range of angles relative to an injection axis; and an optical waveguide having an input grating for diffracting into the waveguide said light over said range of angles such that all of the diffracted light is totally internally reflected within the waveguide and so that image bearing light output from the waveguide has a field of view corresponding to said range of angles, wherein the input grating is a surface relief grating having a profiled reflective surface and at least one layer of dielectric material conforming to the surface for diffracting light over said range of angles into the waveguide.

Abstract: A helmet or head-mounted apparatus has a visor or other curved optical element in front of at least one eye of a wearer, which element also is used as a waveguide. Image-bearing light is injected into the waveguide via an input diffractive element, and propagates through the visor to an output diffractive element which releases the light. The optical powers of the curved waveguide and the input and output diffractive elements are selected so that the released light is delivered as an image to the users eye.