Patents by Inventor Noboru Akiyama
Noboru Akiyama has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 5734616Abstract: A static RAM includes pre-amplifiers, which are made up solely of emitter-follower transistors having their collectors supplied with the power voltage, in one-to-one correspondence to sub common data line pairs which are connected by column switches to complementary data line pairs of memory arrays. The pre-amplifier is provided with a first switch which turns on during the selected state to connect the sub common data line pair to the bases of the transistors and a second switch which turns on during the unselected state to provide the bases with a certain bias voltage lower than the readout signal voltage on the sub common data line pair. The emitter-follower transistors have their emitters connected commonly to form common emitter lines, which are connected to pairs of input terminals of main amplifiers made up of CMOS transistors.Type: GrantFiled: August 8, 1996Date of Patent: March 31, 1998Assignee: Hitachi, Ltd.Inventors: Hideto Kazama, Shuichi Miyaoka, Akihiko Emori, Kinya Mitsumoto, Tomoyuki Someya, Masahiro Iwamura, Noboru Akiyama
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Patent number: 5717684Abstract: A disk cartridge with a case comprises upper and lower shell halves, each of which has a head insertion hole and a spindle insertion hole. A pair of projections are provided inwardly at a joint portion between the two holes. The peripheral wall portions of the spindle insertion hole are extended inwardly toward tips of the projections in an arched form. An almost annular projection is provided along a periphery of the spindle insertion hole to increase a supporting portion for supporting the disk when the spindle is taken off from the spindle insertion hole. The inner peripheral walls of the head insertion hole are chamfered. A corner of the groove is chamfered to prevent the corner of the groove from being caught by a part of the guide frame.Type: GrantFiled: September 20, 1995Date of Patent: February 10, 1998Assignee: Dai Nippon Insatsu Kabushiki KaishaInventors: Noboru Akiyama, Katsumi Kameda
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Patent number: 5661693Abstract: A synchronous memory device is provided in which the cycle time is shorter than conventional memory devices. For example, by providing an output latch in a sense amplifier on a bit line, the time period from input of a clock signal to latching data in the output latch is shortened. In case of plural bit lines, a selector for selecting data in a plural output latch and a latch for latching a sense amplifier selection are provided.Type: GrantFiled: November 22, 1995Date of Patent: August 26, 1997Assignee: Hitachi, Ltd.Inventors: Takashi Akioka, Noboru Akiyama, Masahiro Iwamura, Seigoh Yukutake
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Patent number: 5654856Abstract: A disk cartridge comprises a case with an upper and a lower shell halves united together to accommodate a disk of 3.5 inches therein, a guide portion, a shutter, and a slider slid in the guide portion of the case for supporting the shutter. The shutter is moved by a drive pin to open and close a head and spindle holes. The slider enables the shutter to move smoothly along the guide portion and prevents the shutter from being disconnected from the guide portion when the case is dropped.Type: GrantFiled: January 17, 1996Date of Patent: August 5, 1997Assignee: Dai Nippon Insatsu Kabushiki KaishaInventors: Noboru Akiyama, Katsumi Kameda
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Patent number: 5646897Abstract: A logic circuit is provided for a memory device which can be operated at a high speed with a lower voltage power source level than conventional devices. This logic circuit can be used in a multi-bit test circuit executing the wired-OR-logic operation of complementary logic signals from a plurality of pre-sense amplifiers, receiving the output of the wired-OR-logic operation by an emitter follower using a bipolar transistor, and outputting an AND signal of the complementary logic signals by a level comparing circuit. A sense amplifier is also provided for executing the wired-OR-logic operation of complementary logic signals from a plurality of pre-sense amplifiers, raising the level of the output of the wired-OR-logic operation by a level shift circuit having a semiconductor element for applying an inverse bias potential to an input signal, executing the wired-OR-operation of the shifted up output and outputs from other blocks, and receiving and amplifying the output of the wired-OR-logic operation.Type: GrantFiled: April 21, 1995Date of Patent: July 8, 1997Assignee: Hitachi, Ltd.Inventors: Seigou Yukutake, Masahiro Iwamura, Kinya Mitsumoto, Takashi Akioka, Noboru Akiyama
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Patent number: 5638335Abstract: A memory device comprising a memory array having a plurality of bits, including parity bits, and comprising a plurality of memory blocks, and a bit structure changing section for changing the input/output bits of the memory array, wherein the number of the memory blocks are prescribed to be an integral multiple of three and the input/output bits of the plurality of memory blocks are even. Thereby, the bit structure of the semiconductor memory, having parity bits and which is capable of changing the input/output bits to a plurality of bit structures, can be changed while maintaining the bit structure of the memory blocks even and without increase in propagation delay time.Type: GrantFiled: May 17, 1996Date of Patent: June 10, 1997Assignee: Hitachi, Ltd.Inventors: Noboru Akiyama, Seigoh Yukutake, Sadayuki Ohkuma, Akihiko Emori, Takashi Akioka, Shuichi Miyaoka, Shinji Nakazato, Kinya Mitsumoto
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Patent number: 5638240Abstract: A disk cartridge comprises a case with an upper and a lower shell halves united together to accommodate a disk of 3.5 inches therein, a guide portion, a shutter, and a slider slid in the guide portion of the case for supporting the shutter. The shutter is moved by a drive pin to open and close a head and spindle holes. The slider enables the shutter to move smoothly along the guide portion and prevents the shutter from being disconnected from the guide portion when the case is dropped.Type: GrantFiled: April 19, 1995Date of Patent: June 10, 1997Assignee: Dai Nippon Insatsu Kabushiki KaishaInventors: Noboru Akiyama, Katsumi Kameda
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Patent number: 5627707Abstract: A case supporting structure has four support pins provided in a disk player, a pair of the support pins having two small size locating pins on upper surfaces of the support pins, and four support seat places formed on the lower shell half. A pair of the support seat places respectively have a circular opening to receive one of the locating pins and an elliptic opening to receive loosely another locating pin. The support seat places on the lower shell half are of small smooth areas to be supported on the support pins.Type: GrantFiled: September 1, 1995Date of Patent: May 6, 1997Assignee: Dai Nippon Insatsu Kabushiki KaishaInventors: Noboru Akiyama, Katsumi Kameda
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Patent number: 5619455Abstract: A pipeline-operating type memory system is arranged to have a first input unit for receiving a selector address signal for selecting data; a second input unit for receiving at least an address strobe signal, an X address signal and a Y address signal for selecting data; a first unit for receiving the X address signal and the Y address signal, latching these signals utilizing a first clock signal, and continuously outputting at least either of the X and the Y address signals until these address signals are unlatched; and a second unit for latching a selector address data signal output from the first input unit utilizing the first clock signal, and continuously and selectively outputting at least either of the address signal until the signal is unlatched. The memory system operates to transfer data in a manner to suit the pipeline operating cycle at a normal operating mode and at a fast page mode.Type: GrantFiled: March 23, 1993Date of Patent: April 8, 1997Assignee: Hitachi, Ltd.Inventors: Noboru Akiyama, Yuji Yokoyama, Tatsuyuki Ohta, Kunihiko Suzuki, Yutaka Kobayashi
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Patent number: 5602782Abstract: A pipeline-operating type memory system is arranged to have a first input unit for receiving a selector address signal for selecting data, a second input unit for receiving at least an address strobe signal, an X address signal and a Y address signal for selecting data; a first unit for receiving the X address signal and the Y address signal, latching these signals utilizing a first clock signal, and continuously outputting at least either of the X and the Y address signals until these address signals are unlatched; and a second unit for latching a selector address data signal output from the first input unit utilizing the first clock signal, and continuously and selectively outputting at least either of the address signal until the signal is unlatched. The memory system operates to transfer data in a manner to suit the pipeline operating cycle at a normal operating mode and at a fast page mode.Type: GrantFiled: June 6, 1995Date of Patent: February 11, 1997Assignee: Hitachi, Ltd.Inventors: Noboru Akiyama, Yuji Yokoyama, Tatsuyuki Ohta, Kunihiko Suzuki, Yutaka Kobayashi
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Patent number: 5526342Abstract: A disk cartridge has a case comprising an upper and a lower shell halves for accommodating a disk. The case has a spindle insertion hole, a head insertion hole and a shutter for opening and closing the two holes. The case has at least one of a disconnection preventing mechanism for preventing an elastic spring for urging the shutter from being disconnected from a slider and a part of the case, a drive pin smooth motion mechanism for moving a drive pin on the slider, a shutter locking mechanism for locking the shutter at a closing position, a disk center holding mechanism for supporting the disk at its center position, a disk periphery holding mechanism for holding the periphery of the disk, a writing protection mechanism for prevention new information from being recorded on the disk and a mechanism for forming the case with a good outer appearance.Type: GrantFiled: March 10, 1995Date of Patent: June 11, 1996Assignee: Dai Nippon Insatsu Kabushiki KaishaInventors: Noboru Akiyama, Katsumi Kameda
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Patent number: 5463639Abstract: An automatic pattern synchronizing circuit re-times the phase differences between clocks, thereby adjusting test pattern outputs from a device under test. The automatic pattern synchronizing circuit includes a reference voltage generator for providing a threshold voltage, a comparator for converting an input signal into a rectangular signal, a flip-flop, a pattern-counter part for counting a signal from the flip-flop and a control part for setting the threshold voltage in the comparator. The automatic pattern synchronizing circuit automatically synchronizes voltage patterns. In particular, the high and low voltage levels of the input waveform are automatically measured and the optimum threshold voltage is automatically set.Type: GrantFiled: April 28, 1994Date of Patent: October 31, 1995Assignee: Advantest CorporationInventors: Tetsuya Koishi, Noboru Akiyama, Yasuto Kumai
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Patent number: 5444691Abstract: A guide portion is provided in a front edge of a disc cartridge in an insertion direction to a recording and reproducing apparatus. A slider is slidingly engaged with the guide portion. A shutter is fixed to the slider. Head insertion holes and spindle holes formed in the cartridge case ere opened or closed by the shutter. A generation of friction or wear chips due to the sliding contact between the shutter and cartridge may be prevented.Type: GrantFiled: June 28, 1994Date of Patent: August 22, 1995Assignee: Dai Nippon Insatsu Kabushiki KaishaInventor: Noboru Akiyama
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Patent number: 5436783Abstract: A structure for moving a shutter comprises a slider for supporting the shutter and a spring member for urging the slider. The one end of the slider forms an engaging projection body which has a pair of projections. A dividing groove is extended into the one end of the slider between the two projections. One of the pair of projections is extended in the shutter opening direction longer than the other projection.Type: GrantFiled: April 12, 1994Date of Patent: July 25, 1995Assignee: Dai Nippon Insatsu Kabushiki KaishaInventors: Noboru Akiyama, Katsumi Kameda
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Patent number: 5408458Abstract: A guide portion is provided in a front edge of a disc cartridge in an insertion direction to a recording and reproducing apparatus, A slider is slidingly engaged with the guide portion. A shutter is fixed to the slider. Head insertion holes and spindle holes formed in the cartridge case are opened or closed by the shutter. A generation of friction or wear chips due to the sliding contact between the shutter and cartridge may be prevented.Type: GrantFiled: July 19, 1993Date of Patent: April 18, 1995Assignee: Dai Nippon Insatsu Kabushiki KaishaInventor: Noboru Akiyama
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Patent number: 5406547Abstract: A disk cartridge has a shutter provided on a slider to open and close an opening portion of a case which has a shutter locking mechanism for locking the shutter at its closed position. The shutter locking mechanism comprises a receiving recess provided on the slider, into which a portion of the head of a stopper accommodated in a room of the case is projected in a closed state of shutter.Type: GrantFiled: November 29, 1993Date of Patent: April 11, 1995Assignee: Dai Nippon Insatsu Kabushiki KaishaInventors: Noboru Akiyama, Katsumi Kameda
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Patent number: 5392246Abstract: An area of a semiconductor chip, on which a memory is disposed, is divided into a plurality of memory blocks and redundant memory blocks, each memory block is divided into a plurality of unit arrays of columns for replacing, each redundant memory block is divided into a plurality of unit arrays of redundant columns, a plurality of memory cells are disposed in each unit array of columns for replacing and each unit array of redundant columns, a memory cell group in each unit array of columns for replacing is connected to a word line and a data line, a redundant memory cell group of each unit array of redundant columns is connected to a redundant word line and a redundant data line, a first data selection circuit for controlling data selection with respect to the unit array of redundant columns is disposed in each memory block, a second data selection circuit for controlling data selecting with respect to the unit array group of redundant columns is disposed in each redundant memory block, and a third data selecType: GrantFiled: March 3, 1994Date of Patent: February 21, 1995Assignee: Hitachi, Ltd.Inventors: Noboru Akiyama, Kinya Mitsumoto, Takashi Akioka, Seigoh Yukutake
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Patent number: 5381293Abstract: A disk cartridge comprises a case with an upper and a lower shell halves united together to accommodate a disk of 3.5 inches therein, a guide portion, a shutter, and a slider slid in the guide portion of the case for supporting the shutter. The shutter is moved by a drive pin to open and close a head and spindle holes. The slider enables the shutter to move smoothly along the guide portion and prevents the shutter from being disconnected from the guide portion when the case is dropped. The slider also having grooved projections thereon which allow the projections to compress and be inserted into guide portions of the case.Type: GrantFiled: April 12, 1994Date of Patent: January 10, 1995Assignee: Dai Nippon Insatsu Kabushiki KaishaInventors: Noboru Akiyama, Katsumi Kameda
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Patent number: 5373469Abstract: A high-speed memory employing the pipeline technique is disclosed, in which the minimum operating cycle time is reduced by use of a latch circuit for a small signal using a bipolar transistor. A small-signal latch circuit operating at a signal smaller than an output signal level is inserted between an amplifier circuit for amplifying the data held in a memory cell circuit and an output buffer circuit. A switch signal is also interposed between the latch circuit and the amplifier circuit, thereby shortening the cycle time.Type: GrantFiled: May 29, 1992Date of Patent: December 13, 1994Assignee: Hitachi, Ltd.Inventors: Takashi Akioka, Noboru Akiyama, Yutaka Kobayashi, Tatsuyuki Ohta, Koyo Katsura
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Patent number: 5325257Abstract: A disk cartridge comprises a case with an upper and a lower shell halves united together to accommodate a disk of 3.5 inches therein, a guide portion, a shutter, and a slider slid in the guide portion of the case for supporting the shutter. The shutter is moved by a drive pin to open and close a head and spindle holes. The slider enables the shutter to move smoothly along the guide portion and prevents the shutter from being disconnected from the guide portion when the case is dropped.Type: GrantFiled: September 3, 1993Date of Patent: June 28, 1994Assignee: Dai Nippon Insatsu Kabushiki KaishaInventors: Noboru Akiyama, Katsumi Kameda