According to an embodiment of the present technology, an image display apparatus includes a light source; an image generation unit; and a projection optical system. The image generation unit generates image light by modulating a light beam emitted from the light source. The projection optical system includes a first lens group that is disposed on an optical axis of the generated image light and has a first refractive power, a second lens group that is disposed on the optical axis and has a second refractive power, a first movement mechanism that moves the first lens group, and a second movement mechanism that moves the second lens group corresponding to the first refractive power, the second refractive power, and the movement of the first lens group.

An optical system includes a reflective optical system on a magnification side along an optical path of the projection optical system and a refractive optical system on a reduction side along the optical path. The reflective optical system includes one reflective optical element having a power. The refractive optical system includes a front group on the magnification side and a rear group on the reduction side. The front group having, in order from the magnification side toward the reduction side, a first lens group with a positive or negative refractive power, a second lens group, and a third lens group with a positive refractive power. The rear group has a positive refractive power. The first lens group moves to the magnification side, and the second lens group and the third lens group move to the reduction side in a change in focus from a long distance to a short distance.

A projection system includes a first optical system and a second optical system. The second optical system includes a first lens group disposed on an enlargement side of an intersection position where a chief ray of an off-axis beam having a maximum angle of view intersects with an optical axis of the projection system in the second optical system, a second lens group disposed on the reduction side of the intersection position and having negative power, and a third lens group disposed on the reduction side of the second lens group and having positive power. The second lens group includes a first lens having positive power, a second lens disposed on the reduction side of the first lens and having positive power, and a third lens disposed on the reduction side of the second lens and having negative power. The third lens group includes two lenses each having positive power.

Disclosed systems and methods for the remote detection of atmospheric gas may include (1) receiving, at a collector, thermal infrared energy from at least one atmospheric column, (2) receiving, at optical subsystems, the thermal infrared energy over optical paths, (3) focusing the thermal infrared energy onto diffraction gratings that disperse the thermal infrared energy at a wavelength within a mid-wavelength infrared (MWIR) spectral region and a wavelength within a long-wavelength infrared (LWIR) spectral region, (4) receiving, at detectors, the thermal infrared energy dispersed from the diffraction gratings within the MWIR spectral region and the LWIR spectral region, (5) determining spectral component data associated with the thermal infrared energy in the MWIR spectral region and the LWIR spectral region, (6) sending the spectral component data to a computing device, and (7) identifying an atmospheric gas based on the spectral component data.

A optical projection device disposed close to a projection surface and capable of further widening an angle is provided. A optical projection device includes first optical system including lens groups movable and second optical system reflecting light emitted from the first optical system. The first optical system includes first lens frame which holds first lens group positioned at side closest to the second optical system among the movable lens groups and includes cam pin, guide barrel which includes straight groove, cam barrel which includes cam groove with which the cam pin is engaged, the first lens frame includes frame protruding portion protruding from the cam barrel to second optical system side and holding the first lens group, and notch is provided in such way that portion is formed to be cut out at side through which light reflected by the second optical system passes, in the frame protruding portion.

The present invention discloses an ultra-small-sized 4K-resolution ultra-short-focus projection optical system, which is characterized by including in sequence in a projection direction: a DMD chip, an equivalent prism, a 4K oscillating mirror, a refraction lens assembly and an aspherical reflector. Through reasonable distribution of focal power, the semi-aperture size of the reflector is reduced to be less than 50 mm, and the assembling sensitivity is substantially reduced, so that batch production can be realized.

A front projection display device is provided including an image-generating source configured to generate an image, a wide angle lens system adapted to receive the image, and a screen. The wide angle lens system may be configured to increase distortion of the image in a first stage and decrease distortion of the image in a second stage. The screen may be configured to receive the image from the wide angle lens system on a first side and reflect the image back to a viewer on the first side. In another embodiment, a screen is provided for a front projection system, the screen may be configured to receive light from a steep angle and may include any number of surface topographies configured to reflect light back to the viewer along a desired viewing plane.

A remote imaging apparatus, and corresponding method, includes a hyperbolic primary mirror that receives light from a remote object to be imaged. The primary mirror has a continuous surface that reflects, at least twice, the light from the remote object. The apparatus also includes a hyperbolic secondary mirror having a continuous surface that reflects, at least twice, the light from the remote object. The secondary mirror delivers the light to a field corrector via a port of the hyperbolic primary mirror, and the field corrector is configured to correct for an optical aberration of one or both of the hyperbolic primary and secondary mirrors. Embodiments can provide low distortion, small aspect ratios, and small form factors and moments of inertia for fleets satellite-based and other imaging systems.

An ultra-short throw projector device includes a lens system. The lens system includes a first lens group configured to form a first intermediate image from an incident display image; a second lens group configured to form a second intermediate image from the first intermediate image; an aperture configured to be disposed on a point where the first intermediate image is formed between the first lens group and the second lens group; a reflection mirror configured to reflect and magnify the second intermediate image and form an image on a screen; and a light path changing prism configured to change a light path in the vertical direction or other directions, the prism being disposed at a point on the light path of the lens system, at least one of an incident surface and a refracting surface being an aspherical surface or a freeform surface.

There is provided a projection optical system capable of projecting an image formed on an image forming unit on a projection plane, which has an extremely short projection distance and a small size.