Abstract: In a head-mounted image display apparatus (1) for viewing images on a liquid crystal display means virtually enlarged by an enlarging lens while worn on the head, main apparatus (10) comprises a front case (2), which is positioned at the frontal region side when said main apparatus is worn on the head, and a back case (3), which is positioned at the occipital region. In addition, an air bag (8), which inflates to cause the frontal region to contact a buffer pad affixed to the inside surface of the front case (2), is provided on the inside of the back case (3). The back case (3) is able to rotate on connecting member 5 to the front case (2). Adjustment mechanisms for moving the optical system in the pupil distance direction and in the direction of the optical axes is disposed inside main apparatus (10), and the knobs therefor are centrally disposed on the front of main apparatus (10).

Abstract: A head-mounted display device for enlarging an image formed by an image display element as a virtual image. The head-mounted display device according to this invention comprises a virtual image forming optical system (3) including an image display element (9) and a lens (11) for enlarging an image formed by the image display element (9); a device main body (1) that houses the image forming optical means (3); and a switching means mounted in the device main body (1) for holding the virtual image forming optical system (3) in such a way that the system (3) can be moved in the direction of the width of the eye and placing the virtual image forming optical system (3) in front of one of the user's eyes. The image display element (9) and the lens (11) are disposed so that the optical axis of the virtual image forming optical system (3) approximately aligns with the user's line of sight taken while he or she is looking horizontally.

Abstract: An image intensifier apparatus of this invention comprises a photocathode for converting a first optical image to corresponding photoelectrons, a microchannel plate for multiplying the photoelectrons, impressed with a voltage at both ends thereof, and a fluorescent screen for converting the photoelectrons multiplied in the microchannel plate to a second optical image, emitting the second optical image to an image pickup device. Resistance of the microchannel plate is greater than or equal to 2.8.times.10.sup.15 G.OMEGA. and less than or equal to 2.8.times.10.sup.16 G.OMEGA. per channel.

Abstract: A polarizer optical device for receiving and transmitting light is provided. The polarizer optical device includes a light separating section for separating the light into two polarization components which are othogonal with respect to one another. Further, the optical device is provided with a polarization rotating section for rotating the two polarization components so that a phase difference between the two polarization components othogonal to each other is 1/2.lambda.. Finally, a light combining section is provided for combining the light into a outputted light beam. The light combining section may be formed with a combination of birefringent prisms and isotropic mediums interfacing one another. In these configurations, the refractive index of each prism or medium is selected so that an angle formed with two unparallel incident lights differs from an angle formed with two output or transmitted lights.

Abstract: An optical system, that includes a light source having sufficient coherency to provide a predominate operating wavelength and a diffraction grating lens system to focus the light from the light source to an image point on the optical axis of the optical system, provides for change of position of the image point along the optical axis over a wide focusing range with suppression of generated aberration. In particular, the optical system comprises a light source both movable in the direction of the optical axis and capable of variation in wavelength and a diffraction grating lens system that condenses the beam from the light source onto an image point on and along the optical axis, which system is effective in cancelling out aberration generated due to movement of the light source.