Mitsubishi Denki Kabushiki Kaisha

Takuya Ohira

Masato Saito

Ryo Suzuki

Shigeru Matsuno

Sadayuki Matsumoto

Masakazu Takabayashi

Keiji Fukuyama

Junichiro Hoshizaki

Hiroyuki Teramoto

Kiichi Yoshiara

Keiji Watanabe

Hajime Takeya

Susumu Hoshinouchi

Yoshinori Hatanaka

Minoru Kobayashi

Takashi Shinjo

Ryosuke Namiki

Takashi Hashimoto

Minoru Hashimoto

Hiroshi Yamaguchi

Kinjiro Sano

Hisao Nakanishi

Toyokazu Kamata

Tetsuya Shiroishi

Kiyoshi Saitou

Kiyoshi Saitoh

Riichi Kondo

Kinjirou Sano

Takashi Shinjou

Yoshiko Fujima

A polarization dispersion compensation apparatus includes a polarization controller, a polarization beam splitter, an optical delay circuit, and a polarization beam combiner. The polarization controller controls polarization of an optical signal so that the polarization axis of the input optical signal substantially coincides with the optical axis of an optical transmission line, and the polarization beam splitter section splits the optical signal into two polarized components perpendicular to each other. The optical delay circuit section causes a difference in delay between the two polarized components, and the polarization beam combiner section combines the two polarized components output from the optical delay circuit section. Each of the polarization beam splitter section and the polarization beam combiner section includes a symmetric Mach-Zehnder interferometer having optical transmission lines in two arms, each arm including a temperature control and a birefringence portion for compensating polarization dispersion between the two polarized components.

Polarization dispersion compensating apparatus

A variable dispersion compensator includes an optical waveguide, a temperature controller. The optical waveguide has a chirped grating having a Bragg wavelength changing along the longitudinal direction of the grating. A temperature distribution T (x) is applied to a central portion of the grating, defined as a region where a distance x from an end of the grating is a range of 20 % to 80 % of total length of the grating. Temperature distribution T (x) and T (x) are applied to end portions of the grating, defined as two regions extending from respective ends of the grating to the central region, respectively. At least one of T (x) and T (x) has a distance dependence different from that of the T (x).

Variable dispersion compensator

In a polarization mode dispersion compensating apparatus for controlling polarization mode dispersion of an optical signal, a first optical monitor detects and outputs, based on an optical signal outputted from a first optical transmission line having a grating, a first detection signal indicating magnitude of waveform distortion of the first optical transmission line, and a second optical monitor detects and outputs, based on an optical signal output from a second optical transmission line having a grating, a second detection signal indicating magnitude of waveform distortion of the second optical transmission line. A calculator circuit calculates from the first and second detection signals an output signal. A controller controls a polarization controller based on the output signal from the calculator circuit.

PMD compensating apparatus for controlling polarization controller based on detection of magnitude of waveform distortion

A method of manufacturing a grating in an optical waveguide that includes a core and a cladding covering the core. The method includes scanning a laser beam along an optical axis of the optical waveguide to modulate the refractive index of the core. The core is made of a material having a refractive index that is changeable upon irradiation by radiation. In addition, in scanning the core, the irradiation range of the laser beam is controlled and the core is scanned several times. Therefore, a predetermined distribution of irradiation is obtained in a direction of the optical axis of the grating.

Method of manufacturing grating

A temperature control device for controlling temperature variable devices disposed near a grating of a variable dispersion equalizer including an optical waveguide having the grating. The temperature variable devices control temperatures independently of each other. The temperature control device includes a controller for controlling the temperature variable units, and a storage device which stores temperature control patterns including combinations of control signals for the respective temperature variable units. The controller controls the temperature variable devices with a control signal of at least one of the temperature control patterns selected from the storage device.

Temperature control system for a grating

A cathode for an electron tube provided with a base containing at least one kind of reducing agent, a metal layer whose main component is tungsten formed on the base, and an electron emission material layer whose main component is an alkaline-earth metal oxide including barium formed thereon, deformation of the base in operation is controlled by composing the metal layer with a porous metal layer and limiting the thickness and the porosity of the metal layer. As a result, it is possible to achieve a cathode for an electron tube applicable to a cathode-ray tube for a display in which the cutoff voltage is liable to change.

Cathode for electron tube

Cathode-ray tube having oxide cathode and method for producing the same

An electron tube cathode comprises a base (1) formed mainly of nickel, an alloy layer (4) disposed on the base (1) and including nickel and tungsten having a grain size smaller than that of the base, and an electron emissive material layer (5) deposited on the alloy layer, and including an oxide (6) of an alkaline-earth metal containing at least barium, and a rare earth metal oxide (7) of 0.01 to 25 weight percent and containing at least one of scandium oxide and yttrium oxide. The cathode has a life characteristics improved compared with the prior art, even if operated with a current density of 3 A/cm.sup.2 or more.

Electron tube cathode

A cathode for an electron tube including a base body having nickel as a major component and including at least one kind of reducing agents, a metal member in a layer-like shape, which has as a major component a metal provided with a reducing power equivalent to or smaller than a reducing power of the at least one kind of reducing agents included in the base body and larger than a reducing power of nickel and which is formed on faces of the base body, an electron emitting substance layer formed by depositing alkaline earth metal oxides including barium on the metal member, wherein the metal member is formed on the faces of the base body such that the base body is restrained from deforming by thermal stresses of intermetallic compounds formed at portions of the base body bounded with the metal member.

Cathode for an electron tube

Cathode for electronic tube

A control electrode portion for passing electrons through a given electron-passing hole selected from a plurality of electron-passing holes provided on an insulating substrate is formed by coating the insulating substrate with a conductive film and dividing the into a plurality of conductive films as control electrodes. This structure obviates the mesh structure of electrons which are necessary in the case of arranging control electrodes on the insulating substrate, thereby realizing high-definition display devices with improved luminance. In addition, planar display devices provided with a surface insulated substrate produced by forming an insulating film on a conductive substrate having electron-passing holes and a plurality of separate control electrodes arranged on the surface insulated substrate, it is possible to prevent the charge-up effect which obstructs the passage of electron beams and, hence, to enhance the luminance at least by (1) providing a voltage applying circuit for applying a predetermined voltage to the conductive substrate, (2) providing a portion at which the conductive substrate is exposed between the adjacent control electrodes.

Planar display apparatus having exposed insulated substrate portion

Planar display devices which have a small thickness and used as a display unit of a television set, a monitor or the like. A control electrode portion for passing electrons through a given electron-passing hole selected from a plurality of electron-passing holes provided on an insulating substrate is formed by coating the insulating substrate with a conductive film and dividing them into a plurality of conductive films as control electrodes. This structure obviates the mesh structure of electrons which are necessary in the case of arranging control electrodes on the insulating substrate, thereby realizing high-definition display devices with improved luminance. In addition, planar display devices provided with a surface insulated substrate produced by forming an insulating film on a conductive substrate having electron-passing holes and a plurality of separate control electrodes arranged on the surface insulated substrate, it is possible to prevent the charge-up effect which obstructs the passage of electron beams and, hence, to enhance the luminance by (1) providing a voltage applying means for applying a predetermined voltage to the conductive substrate, (2) providing a portion at which the conductive substrate is exposed between the adjacent control electrodes, and so on.

Planar display apparatus

A flat display apparatus is disclosed which includes a grid interposed between and spaced apart from control electrodes and an electron source. The grid which includes holes has a higher potential applied than the one applied to a cathode so as to enable electrons to pass through the holes. An additional grid may be interposed between and spaced apart from the grid and the control electrodes. Alternatively, a rear electrode is located between adjacent porous cover electrodes to connect them, and a second rear electrode is located near the rear electrode and has a lower potential applied than the one applied to the cover electrodes.

Flat display apparatus with supplemental biasing

A metal layer of not more than 2.0 .mu.m thick is formed on a base, containing nickel as the main ingredient and a reducing agent such as silicon and magnesium, by depositing tungsten by an electron beam under heating in a vacuum. The base is heat treated in a hydrogen atmosphere at 800.degree. to 1,100.degree. C. An emissive material layer, containing an alkali earth metal oxide and 0.01 to 25 wt % of a rare earth metal oxide, the alkali earth metal oxide containing at least barium oxide, is formed on the metal layer. Thus, life characteristics of the cathode, especially during the operation at a high current density such as not less than 2A/cm.sub.2, are greatly enhanced.

Growing community of inventors

Tokyo, Japan

Takuya Ohira