摘要:
An apparatus is described for reading a flat record carrier on which information is stored in an optically readable track-shaped information structure. By the arrangement in the far field of the information structure and at one side of a plane which is formed by the optical axis of an objective system which is used for reading and a line parallel to the center line of the track portion to be read, of a radiation-sensitive detection system which consists of at least two detectors in approximately the position .beta./2, .beta. being the angle at which a first-order beam is diffracted in the lateral direction of the tracks, centering and focussing errors can be detected without the use of auxiliary beams and additional optical elements.
摘要:
A disc-shaped record carrier is described on which information is recorded in an optical structure of trackwise arranged areas and intermediate areas. By adapting the average dimensions of the areas to the average spatial frequencies on the record carrier a read signal can be obtained of sufficient modulation depth and minimal distortion. This is accomplished by increasing the track width with decreasing radius of the record carrier.
摘要:
An opto-electronic system is described for determining a deviation between the actual position of a radiation-reflecting plane in an optical imaging system and the desired position of said plane. Two auxiliary radiation sources are provided which are shifted in opposite directions relative to the optical axis of the imaging system and two radiation-sensitive detectors which are also shifted in opposite directions relative to the optical axis of the imaging system. Of the set of auxiliary radiation sources and the set of detectors the elements of one set are shifted relative to each other in the direction of the optical axis. The auxiliary radiation sources may be formed with the aid of a Fresnel zone plate.
摘要:
A device for detecting a centering error of a rotationally symmetrical surface (0.sub.1, 0.sub.2) of an object (0) with respect to a rotational axis (AR) about which axis the object is rotated for the purpose of the centering error detection is described. Two beams (b.sub.1, b.sub.2 ; b.sub.3, b.sub.4) at angles of approximately 90.degree. are directed onto the object and the variation in the phase difference caused by the centering error (.epsilon.) between the two beams (b.sub.1, b.sub.2 ; b.sub.3, b.sub.4) reflected by the surface is determined.
摘要:
A record carrier is described which is provided with an optically readable structure of trackwise arranged areas alternating with intermediate areas. Areas of at least two different types are provided. As a result, a high information density can be achieved. The different types of areas may also be used for centering a read beam relative to a track and for focussing the beam onto the track.
摘要:
A method and arrangement for aligning a mask comprising a mask-pattern relative to a substrate when the mask-pattern is repeatedly and directly imaged on the substrate, gratings in the mask and gratings on the substrate (phase gratings) being employed as alignment references. The gratings in the mask are located outside the mask pattern and the phase gratings are located on the substrate outside the area where the mask-pattern is imaged. The substrate (phase) gratings are imaged on one of the mask gratings with a projection system which is also used for projecting the mask-pattern on the substrate. The image of the gratings on the grating in the mask is adjusted. Thus, a very accurate alignment can be achieved.
摘要:
An apparatus is described for the pointwise scanning of an information surface. By arranging an observation objective system asymmetrically relative to a zero-order subbeam of the radiation coming from the information surface, and by utilizing a detector whose dimension in the scanning direction is small, the resolution can be increased.
摘要:
An apparatus is described for reading, by means of a beam of radiation, a disk-shaped information carrier which contains spirally arranged video and/or audio signals coded in optical form, which apparatus comprises a source of radiation and a radiation-sensitive signal detector cell, the information carrier being disposed in the radiation path between this source and this detector. By providing at least one grating, consisting of radiation-transmitting and radiation-absorbing stripes and on which an image of part of the grating-shaped structure of the information track in the vicinity of the portion of this track to be read may be formed, and a radiation-sensitive detection system, an accurate indication of axial and radial displacements of the optical imaging system relative to the information carrier can be obtained.
摘要:
Recording and/or reading of information on an optical record carrier is effected by scanning such record carrier with a radiation beam which is focussed by an objective lens into a scanning spot of a size which is diffraction-limited by the aperture of the objective lens. The effective size of the scanning spot is considerably reduced by including a layer of non-linear optical material in the record carrier, such material having an optical characteristic which changes with changes in intensity of the radiation incident thereon. The read/write resolution of information on the record carrier is thereby substantially increased.
摘要:
In a device for displaying three-dimensional pictures, N (with N=2, 3, 4 . . . ) recorded images corresponding to different spatial observation positions are displayed on one or more intermediate display screens (3, 4, 5, 82, 83, 84). The device comprises a viewing screen (6) having lens elements (20, 30) via which corresponding picture segments of the recorded images are displayed. An optical coupling (8, 44) having a plurality of light conductors (8) exists between the viewing screen and the intermediate display screen(s). The light conductors unambiguously associate groups of N corresponding picture segments with lens elements of the viewing screen. By means of the device, three-dimensional pictures can be observed without further auxiliary means for the viewer.