Abstract: A radiation quantum-counting method and apparatus for producing high resolution radiographic images capable of discriminating soft tissue cancer having a lcm size. The high resolution image is generated by a plurality of radiation sensitive elements, each element including a semiconductor material having a pair of electrodes mounted on opposite faces thereof. Each element is highly sensitive and produces a rapid pulse count since the thickness of the semiconductor material is substantially 0.1-0.5 mm, and the semiconductor material has an effective atomic number greater than 30 and an energy band gap greater than 1.3 eV. As a plurality of radiation quanta emanate from the radiation source, they are received by the plurality of radiation sensitive elements which detect individual radiation quantum and produce a pulse signal for each detected quantum. Coupled to each radiation sensitive element is a pulse amplifier for amplifying the pulse signals.

Abstract: In energy separated quantum-counting radiography according to the present invention, radiation penetrating the subject being examined is detected as pulses. The pulses are counted for each radiation energy group, each comprising a separate pulse height group, to thereby speedily obtain a high resolution radiation image of the various materials of the subject.

Abstract: An optical signal recording and reproduction or retrieval system which records a primary signal on a recording track provided on a recording medium by projecting a laser beam which has been modulated by the primary signal onto the recording track, and further records a secondary signal, by superposition, on the recording track by projecting the laser beam which has been modulated by the secondary signal having a frequency band which is different from that of the primary signal onto the recording track for enabling the deleting of the previously recorded primary signal.

Abstract: An optical recording and reproducing disc for recording and/or reproducing information by the application of laser beams having a wavelength .lambda. in the range of 0.7 to 1.0 .mu.m, the disc being constituted by a disc-shaped base having at least one spiral guide track thereon with top surfaces parallel to the surface of the base at a height above the base different from the top surfaces of the portions of the base between the spires of the track, which height is in the range of .lambda./12 to .lambda./6, the guide track having a width approximately equal to the effective diameter of the laser beams; and a uniform thickness coating of a light recording material on the top surface of the guide track and the portions of the base between the spires of the guide track, the light recording material being a material the transmittance and/or the reflectance of which is varied by irradiation by the laser beams.

Abstract: An image display device comprises first and second polarizers having their planes of polarizations oriented at right angles to each other and an electrooptic plate of ferroelectric ceramic material interposed between the first and second polarizers. A matrix electrode arrangement is secured to one surface of the ceramic plate to cause crystallographic structural changes to occur under the influence of a locally generated electric field, so that light passing through the first polarizer is refracted by an amount proportional to the magnitude of the electric field and emerges from the second polarizer with an intensity proportional to the electric field. The electrode arrangement includes a plurality of row electrodes and a plurality of column electrodes to define a plurality of elemental picture areas.

Abstract: A system and a method of recording information by changes of refractive index and light absorption coefficient on a thin film, and reproducing the recorded information byscanning a focussed monochromatic light along a track on a thin film of a selected thickness andletting a light component reflected at a light-incident surface of said thin film and the other light component reflected at an inside face of the opposite surface to said incident surface of the thin film interfere with each other thereby efficiently to vary intensity of reflection light.

Abstract: The optical density and/or the reflectivity of a recording layer included in an optical disk is selectively changed to record information by irradiation with a semiconductor laser beam, while the recording layer may be covered with a suitable protective film. The thickness of the recording layer is so determined that it is able to record information by means of a continuous wave type semiconductor laser beam, while the optical absorption rate of the recording layer is adjusted by setting the percentages of particular additives. The recorded information may be reproduced by the application of a laser beam, the incident power of which is lower than that of the recording beam, to detect the reflected light.

Abstract: An optical information recording material comprising a thin film of a suboxide of a metal or semimetal of Group IIIB, IVB, VB or VIB, e.g. TeO.sub.x where x<2.0 or BiO.sub.x where x<1.5, added with up to 50 mole % of S and/or Se. When irradiated with light of relatively low energy density, the thin film exhibits such changes in optical density that information can be optically recorded on this material with high contrast ratio. Recorded information can be reproduced by either transmitted light or reflected light and, when desired, can be erased by light irradiation of adequate energy density.

Abstract: A method of converting a color negative image into an inverted positive color image and an apparatus for carrying out the method. The image of the color negative film is decomposed into three images each in one of the three primary colors through associated color filters. The individual images thus produced are recorded in a light transmissive recording medium in inverted images, which are then illuminated by a light source disposed at a side in opposition to the negative film, whereby the inverted images are projected through the same optical system including the aforementioned color filters as the one used for the projection onto a screen as the inverted positive image. The recording medium is constituted by a light transmissive ceramic dielectric exhibiting a memory function. The inverted positive image may be projected at a magnified scale.

Abstract: A recorded disk preproducing system in which a signal pattern recorded on a master disk is transferred to a reproducing disk positioned in close contact with the master disk upon exposure to flashing light. The master disk includes a thin film of a light screening material such as in organic compound, chalcogen compound, or the like formed on a transparent glass substrate, and an information signal is recorded on the thin film as a pattern of varied light transmission. The reproducing disk has a thin film of a heat sensitive material such as amorphous chalcogen compound formed on a transparent resin substrate, and the optical density and/or a light reflectance of the heat sensitive thin film is varied in accordance with the recorded signal pattern of the master disk upon exposure to the flashing light.

Abstract: A phosphor for a thermoluminescent radiation dosimeter, comprising lithium tetraborate as a base material and copper as an activator. In addition to these components lithium octaborate may further be included as a base material, and silver as an activator. The phosphors according to the invention have an effective atomic number quite near to that of tissue, so that it is suitable for measuring the radiation dose absorbed by a tissue specimen. Further they exhibit emission a spectra peak at 368 m.mu. which is convenient for measuring the response of widely used photomultiplier tubes. The sensitivities to .gamma.-rays are also improved, compared to the known lithium borate phosphor.

Abstract: An optical information storage material having a substrate and a film deposited on the substrate, the state of said material can be changed from a low optical density state to a high optical density state by the application of electrical, optical or thermal energy. The major component of the film is GeO.sub.x1, SnO.sub.x1, SbO.sub.x2, TlO.sub.x2, BiO.sub.x2 or MoO.sub.x3 wherein 0 < x1 < 2.0, 0 < x2 < 1.5 and 0 < x3 < 3.0. The film can be a mixture of above-mentioned material and an additive for improving the properties thereof. The material is made by vacuum evaporating GeO.sub.2, SnO.sub.2, Sb.sub.2 O.sub.3, Tl.sub.2 O.sub.3, Bi.sub.2 O.sub.3 or MoO.sub.3 under deoxidization conditions.

Abstract: A thin layer of thermoluminescent material is formed on a substrate to form an image storage panel. A radiation image is projected onto the panel, and is stored by the thermoluminescent material.For reading, the panel is scanned by an infrared laser beam, and thermoluminescence proportional to the dose is emitted at the point of impingement of the laser beam. By scanning the storage panel with the laser beam, and by detecting the thermoluminescence, a series of emissions is obtained in the form of a video signal which is used to drive a display device.