A display device includes a first diffraction element that diffracts light emitted from a light source section in front of an observer such that the light is directed to an eye of the observer, and a second diffraction element that is disposed in an optical path from the light source to the first diffraction element to diffract the light such that the light is directed to the first diffraction element. The first diffraction element has a wider wavelength width than the second diffraction element at the half value of diffraction efficiency with respect to light in a first wavelength range, a second wavelength range, and a third wavelength range. This structure reduces a decrease in intensity of the light diffracted by the second diffraction element and the first diffraction element even if a wavelength at which diffraction efficiency is maximum is shifted in the first diffraction element.

A handheld wand comprises a probe at a distal end of the elongate handheld wand. The probe includes a light projector and a light field camera. The light projector includes a light source and a pattern generator configured to generate a light pattern. The light field camera includes a light field camera sensor, the light field camera sensor comprising an image sensor comprising an array of sensor pixels, and an array of micro-lenses disposed in front of the image sensor such that each micro-lens is disposed over a sub-array of the array of sensor pixels.

Optical scanner and electrophotographic image forming apparatus are provided. The optical scanner includes a light source, configured to emit a light beam; an optical deflector, configured to deflect the light beam emitted from the light source; a first optical unit, arranged there-between and including a refraction unit and a diffraction unit; and a second optical unit, arranged in a light exit direction of the optical deflector and configured to make the light beam deflected by the optical deflector form an image on a scanning target surface. A range of a ratio of a refractive power Φ.sub.r to a diffractive power Φ.sub.d of the first optical unit in a main scanning direction is 0.3<Φ.sub.r/Φ.sub.d<0.5; and a range of a ratio of a refractive power Φ.sub.s to a diffractive power Φ.sub.n of the first optical unit in a sub scanning direction is 0.7<Φ.sub.s/Φ.sub.n<1.0.

An image projection device includes: a light source that emits a laser beam; a control unit that generates an image light beam, and controls emission of the image light beam; a scan unit that scans the image light beam to convert it into scan light; a first light converging unit that is disposed before a user's eye, converges the scan light at a first convergence point near a pupil, and then irradiates the retina with the scan light to project the image on the retina; and a second light converging unit that converges the scan light at a second convergence point before the first light converging unit, and then irradiates the first light converging unit with the scan light; wherein a scan angle of the scan light is substantially the same size as a convergence angle at which the scan light converges to the first convergence point.

A method of displaying an image to a viewer includes operating a fiber scanning projector to produce a scanned light beam incident on an incoupling diffractive optical element (DOE) coupled to a waveguide. A portion of the light beam is reflected via a reflective back surface of the incoupling DOE. The reflected portion of the scanned light beam is incident on a reflective optical element, which reflects the light beam back to the incoupling DOE. The returning light beam is then diffracted by the incoupling DOE to produce a second pass first diffracted light beam. The second pass first diffracted light beam is propagated within the planar waveguide via total internal reflection (TIR) to an outcoupling DOE, which directs a portion of the second pass first diffracted light beam toward an eye of a viewer to display the image to the user.

A method for facilitating surgery using an augmented reality system, comprises retrieving patient data relating to a surgical procedure on a patient, generating virtual content comprising a virtual three-dimensional (3D) anatomical model based on the patient data, and displaying the virtual content, such that, when viewed by the first user, the virtual 3D anatomical model appears to be fixed at a physical location, whereby the virtual 3D anatomical model may be viewed by the first user from any angle or orientation merely by walking around the physical location.

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.

A diffraction optical waveguide, a grating structure, and a display device are disclosed. An arrangement period of a grating line of the grating structure is T and the grating line has a cross-sectional profile with a narrow top and a wide bottom. The cross-sectional profile includes five feature points, which respectively have coordinates (0, 0), (L2, H2), (L3, H3), (L4, H4), (L5, 0), and satisfy: 0.2T≤L2<L3<L4≤L5≤T; L3≤0.8T; L3−L2≥0.1T; L4≥0.8T; 0≤H2≤λ; 0.2λ≤H3≤λ; 0.6λ≤H4≤1.8λ; max(H2, H3)≤H4; −0.6λ≤H3−H2≤0.6λ, 0.6λ≤H3+H2≤1.8λ; 0.5λ/T≤H3/L3≤2λ/T, where λ is a wavelength. According to an embodiment of the present disclosure, the cross-sectional profile can be adjusted by controlling parameters of the feature points, the optical effect is improved and degrees of freedom in design and regulation are increased.

Fiducial patterns that produce 2D Barker code-like diffraction patterns at a camera sensor are etched or otherwise provided on a cover glass in front of a camera. 2D Barker code kernels, when cross-correlated with the diffraction patterns captured in images by the camera, provide sharp cross-correlation peaks. Misalignment of the cover glass with respect to the camera can be derived by detecting shifts in the location of the detected peaks with respect to calibrated locations. Devices that include multiple cameras behind a cover glass with one or more fiducials on the cover glass in front of each camera are also described. The diffraction patterns caused by the fiducials at the various cameras may be analyzed to detect movement or distortion of the cover glass in multiple degrees of freedom.

An optical imaging system employing a device containing a sequence of first (pre-dispersor) and second (main) volume holograms configured to operate as a sequence of optical diffractive elements possessing different blazing curves. A pre-cursor hologram has a thickness smaller than the thickness of the following, disperser hologram, and a comparatively broad spectral selectivity as compared to that of the main hologram, allowing the pre-cursor to diffract light in transmission within a very large range of the angles of incidence. The use of the combination of the pre-cursor and the main holograms not only implements selective imaging of the chosen target object at every angle at which various portions of the object are seen at the optical system, but also facilitates the spectroscopic measurements of such object.