Hitachi, Ltd.

Kouji Kuwabara

Hiroyuki Sugawara

Kouji Sasaki

Toshiharu Shirakura

Satoshi Takemori

Hiroshi Kitaguchi

Shigeru Izumi

Tarou Takagi

Noriyuki Sadaoka

Shouhei Numata

Hiroshi Kamimura

Makoto Yano

Katsutoshi Satoh

Atsushi Yamagoshi

Yukio Kawakubo

Kiyoshi Okumura

Minoru Fujimoto

Kiyoshi Saito

Takao Umeda

Tadashi Sato

Yoshio Yoshioka

Hiroo Ohkawa

Kouji Ishiguro

Tuneyoshi Oohashi

Toshimichi Kichikawa

Kiwamu Takehisa

Norio Ikemoto

An X-ray sensor signal processing circuit and method used in an industrial X-ray CT apparatus for processing an output signal of a semiconductor X-ray sensor which detects a pulsed X-ray emitted from an accelerator and passed through an object to be inspected. The circuit includes a first resistor having one terminal connected to the X-ray sensor and an other terminal connected to ground, a first capacitor having one end terminal connected to a connection point of the X-ray sensor and the first resistor, an operational amplifier having an inverting input connected to an other terminal of the first capacitor, and an integrator having a second resistor and a second capacitor each connected to the operational amplifier in parallel. The circuit is configured so that at least bias conditions of the X-ray sensor and the first capacitor are returned to a steady state after irradiation of the pulsed X-ray.

X-ray sensor signal processor and X-ray computed tomography system using the same

An X-ray CT apparatus having X-ray irradiator for irradiating an X-ray to an object to be inspected, an X-ray sensor for detecting an X-ray passed through the object to be inspected, an X-ray sensor signal processing circuit for processing an output signal from the X-ray sensor, and a CT control apparatus for reconstructing an image of the object to be inspected on the basis of an output signal of the X-ray sensor processed by the X-ray sensor signal processing circuit. The X-ray sensor signal processing circuit removes a DC component from the output signal of the X-ray sensor and integrates the output signal of the X-ray sensor having the DC component removed therefrom.

An X-ray CT apparatus having X-ray irradiator for irradiating an X-ray to an object to be inspected, an X-ray sensor for detecting an X-ray passed through the object to be inspected, an X-ray sensor signal processing circuit for processing an output signal from the X-ray sensor, and a CT control apparatus for reconstructing an image of the object to be inspected on the basis of an output signal of the X-ray sensor processed by the X-ray sensor signal processing circuit. The X-ray sensor signal processing circuit includes a filter for removing a DC component from the output signal of the X-ray sensor, and an integration circuit for integrating the output signal of the X-ray sensor from which the DC component is removed by the filter.

An X-ray CT apparatus having X-ray irradiator for irradiating an X-ray to an object to be inspected, an X-ray sensor for detecting an X-ray passed through the object to be inspected, an X-ray sensor signal processing circuit for processing an output signal from the X-ray sensor, and a CT control apparatus for reconstructing an image of the object to be inspected on the basis of the output signal of the X-ray sensor processed by the X-ray sensor signal processing circuit. The X-ray sensor signal processing circuit includes a filter for removing a DC component from the output signal of the X-ray sensor and a circuit for obtaining a difference between a voltage corresponding to a current including a dark current generated in the X-ray sensor by incidence of the X-ray and a voltage corresponding to the dark current.

An X-ray CT apparatus having X-ray irradiator for irradiating an X-ray to an object to be inspected, an X-ray semiconductor sensor for detecting an X-ray passed through the object to be inspected, an X-ray sensor signal processing circuit for processing an output signal from the X-ray semiconductor sensor, and a CT control apparatus for reconstructing an image of the object to be inspected on the basis of the output signal of the X-ray semiconductor sensor processed by the X-ray sensor signal processing circuit. The X-ray sensor signal processing circuit includes a filter for removing a DC component from the output signal of the X-ray semiconductor sensor, and an integration circuit for integrating an output signal of the X-ray semiconductor sensor from which the DC component is removed by the filter.

An X-ray sensor signal processor including capacitorsfor removing DC components (dark currents) from output signals of semiconductor sensorstodetecting pulse-like X-rays passed through an object, and integrators (each of which is constituted by a combination of an operational amplifiera resistorand a capacitor) for integrating the output signals of the X-ray sensors after removal of the DC components by the capacitorsBy this, a value proportional to the average number of photons in X-rays can be obtained even in the case where a small number of incident photons are given, and an X-ray CT system using the X-ray sensor signal processor.

X-ray sensor signal processor and x-ray computed tomography system using the same

There is disclosed a solid-state laser resonator capable of outputting a high power linearly polarized laser beam, in which a laser beam subjected to the birefringence in the laser resonator is effected to minimize a component of the laser beam which is orthogonal with the direction of polarization definable by a Brewster plate upon traversing a quarter-wave plate, to enable the linear polarization output distribution of the laser beam to become uniform. With this, the emission efficiency and the output power of a linearly polarized laser beam are much improved.

High-power solid-state laser resonator

A method and a device are provided for generating a multi-pulse laser beam including at least three laser beams, from a single pulse laser beam oscillated from a single laser beam source and a method and an apparatus using the pulse generator for laser beam machining with a two-wavelength multi-pulse laser beam suitable for fine-patterning a multi-layered circuit board formed of metal thin films and resin layers or ceramic bodies. One pulse laser beam from the laser beam source is separated into linear polarized laser beams in first and second directions by a polarization beam splitter, with the beam in the first direction being outputted as a first pulse beam of the multi-pulse beam. The beam in the second direction is incident to a combination of an optical fiber or a glass plate and a 1/4 wavelength plate, and is delayed and non-linearly polarized there to become a delayed and non-linearly polarized laser beam. The laser beam is again incident to the polarization beam splitter, where the delayed non-linearized pulse beam separated in the first direction is outputted as a second pulse beam of the multi-pulse laser beam. The delayed non-linearized pulse beam separated in the second direction is passed again through the above-described delay and non-linearization loop to generate a third pulse beam.

Multi-pulse laser beam generation method and device and laser beam

A light beam (30) including a random polarization and radiated from a light source, such as laser oscillator (6) is separated into P wave polarization light beam and S wave polarization light beam by a beam splitter 33. After modulated by image information representative of characters to be printed, both the P and S wave polarization beams are merged and the resultant light beam is projected on the surface of a workpiece for marking a pattern.

Apparatus for reducing, enlarging and projecting image information

A laser marking apparatus comprises a pulse laser oscillator which emits a linearly polarized laser beam; a transmission type liquid crystal mask which displays a pattern to be marked on an article in one of a positive pattern display mode and a negative pattern display mode by dots arranged in a matrix form and which allows to pass the emitted laser beam but differentiates the polarization plane of the laser beam which has passed through masked portions from that through unmasked portions; a polarized beam splitter disposed downstream the transmission type liquid crystal mask for selectivity passing the laser beam to be irradiated on the article to be marked from the transmission type liquid crystal mask; a TV camera for detecting a discriminator indicating the thermal conductivity of the article to be marked; a recognition unit which determines the thermal conductivity of the article to be marked based upon the detected discriminator; and a control unit which controls the transmission type liquid crystal mask to operate in one of the positive pattern display mode and the negative pattern display mode based upon the determined thermal conductivity of the article to be marked in such a manner that when the determined thermal conductivity of the article to be marked is low, the positive pattern display mode is selected and when the determined thermal conductivity of the article to be marked is high, the negative pattern display mode is selected.

Laser Marking apparatus

Disclosed is a liquid crystal mask type laser marking system for transferring a pattern information onto an object to be worked. A laser beam emitted from a laser oscillator is applied to a liquid crystal mask having a pattern mask. The laser beam outgoing from the liquid crystal mask is applied to a wavelength converter, which converts the laser beam to one having a wavelength to which the object to be worked is sensitive. The converted laser beam is applied to the object to be worked.

Liquid crystal mask type laser marking system

A laser device equipped with a high-voltage pulse generator wherein the pulse generator supplies an electric energy from a dc power source in an on-off form of a supply voltage to a tank circuit through a transformer, with the switching on and off of the supply voltage being effected in synchronism with the resonance period of the tank circuit. The tank circuit stores the supplied electric energy as a resonance condition so that when the electric energy stored in the tank circuit reaches a predetermined value, a saturable reactor connected between the laser device and the tank circuit becomes saturated and the electric energy in the tank circuit is discharged to the laser device.

Laser device with high-voltage pulse generator, high-voltage pulse

A laser marker comprises a liquid crystal device for displaying pattern information representative of a character to be printed on an object to be worked, a pulse laser oscillator, a liquid crystal device power switch connected to the liquid crystal device, a laser switch connected to the pulse laser oscillator, and timer circuits operative to retard the operation of the laser switch with respect to that of the liquid crystal device power switch, whereby after the character to be printed is displayed properly on the liquid crystal device, a pulse laser beam is irradiated on the liquid crystal device so as to sharply print the character on the object.

Laser marker and method of laser marking

A discharge tube structure of a gas laser generator has end common vessels at its both end sections and an intermediate common vessel at its intermediate section. The end common vessels and intermediate common vessel are connected through the first and second cooling ducts to a centrifugal blower, which is provided at its center the first communicating port communicating with the first cooling duct and at least two second communicating ports communicating with the second cooling ducts opposed to each other with respect to the first communicating port. The simplified second cooling ducts allows the mixture gas to be supplied smoothly to the intermediate common vessel, thereby increasing the laser output.

Gas laser generator

A gas laser device has an anode and a cathode arranged oppositely in a discharge tube. The cathode comprises a plurality of cathode members each having a predetermined discharge effective cathode surface and each being electrically isolated from others. A switching circuit selects the cathode member(s) used for a continuous wave oscillation and the cathode member(s) used for a pulsed oscillation. The total area of the discharge effective cathode surface(s) of the cathode member(s) used for the pulsed oscillation is selected to be smaller than, preferably 1/3 to 1/2 of that of the discharge effective cathode surface(s) of the cathode member(s) used for the continuous wave oscillation.

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Hitachi, Japan

Kouji Kuwabara