Matsushita Electric Industrial Co., Ltd.

Masaru Ikedo

Masafumi Watari

Tadaoki Yamashita

Yoshitake Yasuno

Osamu Yamamoto

Hiroshi Tsutsui

Kazuhiro Kayashima

Takuhiro Ono

Takeo Miyata

Fumikazu Tateishi

Takashi Iwabuchi

Yoshiaki Hayashi

Hajimu Oonishi

Kiyoko Ohshima

Koyoko Ohshima

A method of manufacturing an unclad infrared optical fiber hot extrudes silver halide crystals through a die while simultaneously applying a pressure of 5 to 15 tons/cm.sup.2 to the crystals and a tensile load to the forming fiber, the tensile load being greater than the yield stress but smaller than the rupture stress of the infrared optical fiber. The method provides an infrared fiber having minimal variation in linearity.

Method of manufacturing an infrared optical fiber

An infrared optical fiber is disclosed which has a composition ratio of silver chloride and silver bromide in the range of 30 to 70 percent by weight of silver chloride, and has a diameter of 0.5 mm or less. The infrared optical fiber has great mechanical strength, so that it does not burn because of degradation in the laser beam transmission capability, even after 2,000 times of repetitive bending with a curvature radius of 20 mm, which is the condition necessary for use within the interior of a body, and it exhibits excellent radiant optical characteristics. In particular, an infrared optical fiber with a diameter of 0.35 mm or less is preferred, because such an infrared optical fiber withstands over 10,000 times of repetitive bending under the same condition as above and can therefore be repeatedly used many times. Also, by applying an appropriate load to the infrared optical fiber, the infrared optical fiber, which is of straight shape free from curving and which has excellent radiant optical characteristics, can be produced stably with a short manufacturing period of time. Furthermore, an optical fiber cable using such an infrared optical fiber, in which the infrared optical fiber is housed in a protective tube containing a dry inert gas, can be repeatedly used under wet conditions of high humidity and can be stored under ambient conditions for a long period of time.

Infrared optical fiber, a method of manufacturing the same, and an

A method of operating a laser is disclosed which includes irradiating an optical component in an atmosphere of dry air or dry inert gas with a laser beam, wherein the optical component is provided with an antireflection film having at least a layer of calcogenide glass and a layer of potassium chloride or lead fluoride.

Antireflection film

An antireflection film composed of a layer of arsenic triselenide having an optical thickness in the range between 2.518 and 2.783 .mu.m, a layer of potassium chloride having an optical thickness in the range between 1.151 and 1.272 .mu.m and a layer of arsenic triselenide having an optical thickness in the range between 0.577 and 0.749 .mu.m which are successively formed on a member of infrared radiation transmitting material formed of a mixture of thalium iodide and thalium bromide. The member provided with the three-layer antireflection film is used in an atmosphere of protective gas, such as dry air or dry N.sub.2 gas.

An optical fiber which is able to transmit high power infrared energy, and is flexible and long in life is described. The fiber consists essentially of a mixed crystal of 40 to 45 wt % of thallium bromide and the balance of thallium iodide, each having a purity not less than 99.9%. The fiber is free of any particles having a size not smaller than 1 .mu.m.

Optical fiber for infrared transmission consisting essentially of high

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. In each elemental area the electrode arrangement includes a diode, first parallel finger electrodes connected to a row electrode via the diode and second parallel finger electrodes connected to a column electrode and staggered relative to the first finger electrodes.

Image display device utilizing birefringence properties of ferroelectric

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.

Image converting and projecting method and apparatus for carrying out

A method of thermoluminescent dosimetry employing infrared radiation heating of a dosimeter. An incandescent lamp is used for the source of infrared radiation. The dosimeter is provided with a infrared radiation absorbing layer connected thermally to a thermoluminescent material layer. The infrared radiation absorbing layer is irradiated with infrared radiation, so that thermoluminescent material is not directly irradiated. The lamp is initially powered whereby the dosimeter is heated by infrared radiation of such high intensity as to tend to cause a heat equilibrium in the dosimeter above the temperature where thermal radiation is generated from the dosimeter. Then the power supplied to the lamp is cut or decreased, so that the dosimeter is heated by the afterglow of the lamp. Therefore the rate of temperature rise of the dosimeter becomes quite slow in the latter half of heating process, whereby the temperature of dosimeter easily falls into the required range.

Method of reading thermoluminescent dosimeter

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.

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Neyagawa, Japan

Masaru Ikedo