In an optical system, a first optical section having positive power, a second optical section provided with a first diffractive element and having positive power, a third optical section having positive power, and a fourth optical section provided with a second diffractive element and having positive power are disposed along a light path of image light emitted from an image light generation device. A first intermediate image of the image light is formed between the first optical section and the third optical section, a pupil is formed in the vicinity of the third optical section, a second intermediate image of the image light is formed between the third optical section and the fourth optical section, and the fourth optical section collimates the image light to form an exit pupil. The first diffractive element and the second diffractive element are in a conjugate relation or a roughly conjugate relation.

An image in a predetermined hue is displayed at a display surface, and is emitted as image light. The image light is guided to a display position by an optical system, and is deflected by a diffraction optical element. The emitted image light includes light emitted from a first position of the display surface and light emitted from a second position of the display surface. A deflection angle at which the light emitted from the first position is diffracted by the diffraction optical element is larger than a deflection angle at which the light emitted from the second position is diffracted by the diffraction optical element. Of the image light in a wavelength range expressing the hue, a wavelength peak of the light emitted from the first position is present on a long wavelength side with respect to a wavelength peak of the light emitted from the second position.

A diffractive optical member includes a hologram element, a support member that supports the hologram element by contacting the hologram element from one side, and a covering film member that is a first film member and covers the hologram element by contacting the hologram element from a side opposite to the one side. The covering film member includes a coupling portion that is in contact with the support member, and the coupling portion is separated from the hologram element.

The present invention features new waveguide layouts for input, redirection (expansion), and output holograms that minimize cross talk between colors and allow all three colors to reside in a single waveguide. The use of multiple incoupling holograms that diffract different colors of light in different directions, or along different paths, through a waveguide substrate advantageously provides for a reduction of cross-talk between the colors of a holographic image. In a square-shaped design, red, green, and blue input and output holograms approximately overlay on top of each other. The green redirection hologram is laterally separated from the red and blue redirection holograms. Using this square-shape design, the light beams for the three colors are separated into two paths propagating from input to output holograms.

Disclosed is an improved diffraction structure for 3D display systems. The improved diffraction structure includes an intermediate layer that resides between a waveguide substrate and a top grating surface. The top grating surface comprises a first material that corresponds to a first refractive index value, the underlayer comprises a second material that corresponds to a second refractive index value, and the substrate comprises a third material that corresponds to a third refractive index value.

A holographic projector comprises an image processing engine arranged to, a hologram engine and a display engine. The image processing engine is arranged to receive a source image for projection. The source image comprises a first colour component and a second colour component. The image processing engine is further arranged to form a first colour secondary image from the first colour component by nulling alternate pixel values of the first colour component in accordance with a first checkerboard pattern. The image processing engine is further arranged to form a second colour secondary image from the second colour component by nulling alternate pixel values of the second colour component in accordance with a second checkerboard pattern. The first checkerboard pattern is opposite to the second checkerboard pattern. The hologram engine is arranged to determine a first colour hologram corresponding to the first colour secondary image and a second colour hologram corresponding to the second colour secondary image. The display engine is arranged to form a first colour holographic reconstruction from the first colour hologram and a second colour holographic reconstruction from the second colour hologram.

It is an objective of this disclosure to protect a highly transparent hologram light guide plate from water vapor and ultraviolet ray, thereby suppressing deterioration of the hologram light guide plate even when employed in a head mount display used in outdoor environments. A hologram light guide plate according to this disclosure comprises a protection layer that protects a hologram layer and an intermediate layer that is placed between a glass layer and the protection layer, wherein the glass layer and the hologram layer form a transfer layer that transfers image light. The intermediate layer causes the image light to transfer only in the transfer layer in a section from an input area of the image light to an output area of the image light.

Disclosed is an improved diffraction structure for 3D display systems. The improved diffraction structure includes an intermediate layer that resides between a waveguide substrate and a top grating surface. The top grating surface comprises a first material that corresponds to a first refractive index value, the underlayer comprises a second material that corresponds to a second refractive index value, and the substrate comprises a third material that corresponds to a third refractive index value.

An eye is illuminated with illumination light. A wavefront image of retina-reflected light is generated and an accommodative eye state value is determined based at least in part on the wavefront image.

Techniques disclosed herein relate to a near-eye display system. One example of an eye-tracking system includes a substrate transparent to visible light and infrared light and a reflective holographic grating conformally coupled to a surface of the substrate. The reflective holographic grating is configured to transmit the visible light and reflectively diffract infrared light in a first wavelength range for eye tracking. The refractive index modulation of the reflective holographic grating is apodized in a direction along a thickness of the reflective holographic grating to reduce optical artifacts in the visible light.