A head up display can use a catadioptric collimating system. The head up display includes an image source. The head up display also includes a collimating mirror, and a polarizing beam splitter. The light from the image source enters the beam splitter and is reflected toward the collimating mirror. The light striking the collimating mirror is reflected through the beam splitter toward a combiner. A field lens can include a diffractive surface. A corrector lens can be disposed after the beam splitter.

The imaging lens consists of, in order from the object side, a front group, an aperture stop, and a rear group. The front group includes a diffractive optical element having a positive lens and a negative lens in order from the object side. A diffractive surface is provided between an object side surface of the positive lens and an image side surface of the negative lens. Assuming that a distance on an optical axis from the diffractive surface to the aperture stop in a state in which an object at infinity is in focus is Ddoe, and a focal length of the whole system in a state in which the object at infinity is in focus is f, the imaging lens satisfies Conditional Expression (1): 0.02<Ddoe/f<0.11.

According to an embodiment, a method of producing a lens unit in which lens unit is formed by curing a light-transmitting resin and includes a plurality of lens portions includes: forming, by resin, a first lens portion including a first lens surface and a second lens surface; forming, by resin integrally with first lens portion, a cylindrical support portion extending in a direction parallel to an optical axis direction of first lens portion; forming, by resin integrally with support portion, a second lens portion including a third lens surface facing second lens surface and a fourth lens surface, and having an optical axis coinciding with optical axis of first lens portion; and forming a diffraction grating integrally when any one or more of first lens surface, second lens surface, third lens surface, and fourth lens surface is formed.

A high magnification MWIR continuous zoom optical system is described herein that consists of the following components: a front detachable extender group, a fixed group for focusing incoming radiation, three moving groups for zooming and generating an intermediate image and a relay group. The mentioned optical system has the ability to work with MWIR radiation (3-5 m) and generate a thermal image from the gathered radiation. The system also has the ability to zoom continuously in a wide variable focal length range with a high magnification ratio of 20. With the use of a cooled detector, the combined system allows its user to be able to receive high quality thermal images in all FOV configurations.

A light redirecting film and a method for manufacturing the same are provided. The light redirecting film comprises a substrate, a first diffraction grating layer of a first curable resin on the substrate and a second diffraction grating layer of a second curable resin on the first diffraction grating layer. Wherein the grating directions of the first diffraction grating layer and the second diffraction grating layer cross each other at an angle of 9010, and the difference of the refractive index of the first curable resin and the second curable resin is no less than 0.1 and no more than 0.3.

A light redirecting film in a sandwich-laminated structure is provided. The light redirecting film comprises a first layer, a second layer; and an intermediate layer sandwiched between the first layer and the second layer. The intermediate layer includes a first grating surface having a plurality of first gratings extending in a first grating direction and a second grating surface opposite to the first grating surface having a plurality of second gratings extending in a second grating direction, wherein the first grating direction and the second grating direction cross each other at an angle of 9010, and the first grating surface and the second grating surface of the intermediate layer are gap-filled and planarized with the first layer and the second layer respectively to generate the light redirecting film.

Disclosed is a four-dimensional (4D: 3D+time) multi-plane broadband imaging apparatus capable of recording 3D multi-plane and multi-colour images simultaneously. The apparatus comprises: one or more non-reentry quadratically distorted (NRQD) gratings (5) which can produce a focal length and a spatial position corresponding to each diffraction order, thus simultaneously transmitting wavefront information between multiple object/image planes (2) and a single image/object plane (7); a grism system (4) which can limit chromatically-induced lateral smearing by creating a collimated beam in which the spectral components are laterally displaced; a lens system (3) which is configured to adjust the optical path; and the optical detector(s) (6). In an optical system, the multiple object/image planes (2), the lens system (3), the grism system (4), the NRQD grating(s) (5), the optical detector(s) (6) and the single image/object plane (7) are located on the same optical axis (1). This simple, easy-to-use and compact apparatus can meet many different requirements and serve a large range of high throughput applications.

A method for assessing the similarity between a power profile of a manufactured optic device and a nominal power profile upon which the power profile of the manufactured optic device is based. The method comprises measuring the power profile of manufactured optic device, identifying a region of interest from the measured power profile of manufactured optic device, and applying an offset to the measured power profile to substantially minimize a statistical quantifier for quantifying the similarity between the nominal power profile and the offset measured power profile. The method further comprises comparing the offset and the statistical quantifier to predefined quality control metrics, determining whether the measured power profile meets the predefined quality control metrics based, at least in part on the comparison. In exemplary embodiments, the method may further comprise determining whether to associate the manufactured optic device with another nominal power profile, if the measured power profile does not meet the predefined quality control metrics.

A diffractive optical element 10 includes a first diffraction grating 4, a second diffraction grating 5, films 6 formed between the first diffraction grating 4 and the second diffraction grating 5. The DOE 10 satisfies a conditional expression of n.sub.2<n.sub.1<n.sub.ha, where n.sub.ha is an average refractive index of films 6b formed between grating wall surfaces 4b and grating wall surfaces 5b at a wavelength of 550 nm, n.sub.1 is a refractive index of the first diffraction grating 4 at a wavelength of 550 nm, and n.sub.2 is a refractive index of the second diffraction grating 5 at a wavelength of 550 nm. The films 6b and films 6a that are formed between grating surfaces 4a and grating surfaces 5a satisfy a predetermined relationship.

Provided is a focusing device that includes a substrate and a plurality of scatterers provided at both sides of the substrate. The scatterers on the both sides of the focusing device may correct geometric aberration, and thus, a field of view (FOV) of the focusing device may be widened.