A near-eye display system comprising an image source, a modulation stack, and an imaging assembly. The modulation stack, in one embodiment, comprises one or more digital light path length modulators.

A telescope includes a primary mirror, a secondary mirror configured to move along a first axis, and a tertiary mirror configured to move along a second axis. The secondary and tertiary mirrors are configured to move along respective axes in a synchronized manner to focus a beam of electromagnetic radiation from the primary mirror. The telescope further may include an anamorphic deformable mirror configured to achieve wavefront control and correction of optical aberrations. The telescope further may include a first linear actuator configured to move the secondary mirror along the first axis and a second linear actuator configured to move the tertiary mirror along the second axis.

A telescope includes a primary mirror, a secondary mirror configured to move along a first axis, and a tertiary mirror configured to move along a second axis. The secondary and tertiary mirrors are configured to move along respective axes in a synchronized manner to focus a beam of electromagnetic radiation from the primary mirror. The telescope further may include an anamorphic deformable mirror configured to achieve wavefront control and correction of optical aberrations. The telescope further may include a first linear actuator configured to move the secondary mirror along the first axis and a second linear actuator configured to move the tertiary mirror along the second axis.

The focus-corrected optical filter apparatus includes multiple optical filter assemblies supported by a movable support member. Each optical filter assembly includes an optical filter and a corrector that form a filter-corrector pair that move together with the support member. Each corrector is formed to compensate for the adverse effects of chromatic aberration of a focusing lens at the given wavelength of the corresponding optical filter in the filter-corrector pair. Example correctors are flat glass plates with different thicknesses. The focus-corrected optical filter apparatus is arranged so that the different optical filter assemblies can be sequentially inserted into the optical path of a focused multi-wavelength light beam to sequentially form substantially monochromatic focused light beams having the different wavelengths but have the same focus position.

A system to adjust light path length comprising a digital light path length modulator, the digital light path length modulator comprising a polarization modulator to receive polarized light and to modulate a polarization of some or all of the polarized light. The system further comprising an optical path length extender (OPLE) having an entry surface and an exit surface, to direct the light entering the OPLE with a first polarization through the entry surface and along a first light path through the OPLE to exit through the exit surface, and to direct the light entering the OPLE with a second polarization through the entry surface and along a second light path through the OPLE to exit through the exit surface, the second light path through the OPLE having a light path length two or more times longer than the first light path length through the OPLE.

A near-eye display system comprising an image source, a modulation stack, and an imaging assembly. The modulation stack, in one embodiment, comprises one or more digital light path length modulators.

An inner surface image inspection apparatus includes: an image-capturing unit; a lens-barrel attached in front of the image-capturing unit, the lens-barrel containing lenses; an insert unit of a cylindrical shape attached to a leading end of the lens-barrel, the insert unit adapted to be inserted into the hole of the inspection object; a mirror disposed in the insert unit in such a manner that a reflecting surface of the mirror is inclined relative to the optical axis of the lenses of the optical system; and a linear motion mechanism configured to move the mirror in parallel to the optical axis.

A system comprising an optical path length extender (OPLE) having two light paths having different path lengths, such that light entering the OPLE with a first polarization is directed through a first light path, and light entering the OPLE with a second polarization is directed through a second light path through the OPLE. The OPLE includes a first polarization sensitive reflective element at a first angle to the light entering the OPLE and a second angled polarization sensitive reflective element at a second angle to the light entering the OPLE, the second angled polarization sensitive reflective element intersecting the first polarization sensitive reflective element. The system further includes a mirror with an optical power.

A method includes providing frames of video data for being displayed by a head mounted display (HMD). Pixel data is encoded in a pixel of at least some of the video data frames, the encoded pixel data defining a focal state of an optics block of the HMD for displaying the respective frame of the video data to a user. The predetermined focal state is determined from a plurality of available focal states of the optics block, each focal state corresponding to a different focal plane of a virtual image generated based on the video data. The pixel used for encoding may be disposed outside a region of the frame that is displayable by the HMD.

An image capture system comprising an optical path length extender (OPLE) to direct the light having a first polarization through a first light path through the OPLE, and to direct the light having a second polarization through a second light path through the OPLE, the first and second light paths having different light path lengths. The image capture system further comprising an image sensor to capture a plurality of image portions at a plurality of focal distances.