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Dive into the research topics where Yoshihiro Nonaka is active.

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Featured researches published by Yoshihiro Nonaka.


ieee international magnetics conference | 1999

Write performance of heads with a 2.1-Tesla CoNiFe pole

Keishi Ohashi; Noboru Morita; Tadaaki Tsuda; Yoshihiro Nonaka

We examined the write performance of heads with a CoNiFe/NiFe composite write pole. The saturation induction B/sub s/ of the CoNiFe film was 2.1 T (21 kG). The CoNiFe layer thickness was typically 0.5-0.6 /spl mu/m, and the rest of the write pole was composed of Ni/sub 80/Fe/sub 20/. The dual high B/sub s/ layer structure with the CoNiFe films on both sides of the write gap gave excellent overwrite performance. It was over 30 dB for a medium that had a high coercivity of 560 kA/m (7.0 kOe).


SID Symposium Digest of Technical Papers | 2004

54.1: A Low-Power SOG LCD with Integrated DACs and a DC-DC Converter for Mobile Applications

Yoshihiro Nonaka; Hiroshi Haga; Hiroshi Tsuchi; Youichi Kitagishi; Tadahiro Matsuzaki; Mitsuhiro Sugimoto; Hiroshi Hayama; Hideki Asada

A low-power 262k-color SOG (System-On-Glass) LCD has been developed for mobile applications. It is integrated with a DC-DC converter and driver circuits that contain 6- bit DACs, and it consumes less than 5 mW in operations with a single voltage power supply of 2.5 V.


ieee international magnetics conference | 2000

Co-Ni-Fe write heads with a 10-/spl mu/m yoke length for high-speed recording

Yoshihiro Nonaka; Hiroaki Honjo; Tamaki Toba; Shinsaku Saito; Tsutomu Ishi; Mikiko Saito; Nobuyuki Ishiwata; Keishi Ohashi

We have developed a Co-Ni-Fe write head with a short yoke length for high-speed recording. By reducing the yoke length to 9.5 /spl mu/m, the eddy currents induced in a yoke with a relatively low resistivity (0.2 /spl mu//spl Omega/m) were reduced. The head of this short yoke had good write performance for a medium with a coercivity of 400 kA/m (5000 Oe) at frequencies up to 250 MHz (the overwrite less than -30 dB, and nonlinear transition shift less than 7%).


SID Symposium Digest of Technical Papers | 2003

51.1: A DC-DC Converter Circuit Integrated into a Poly-Si TFT LCD Containing a 6-bit DAC

Yoshihiro Nonaka; Hiroshi Tsuchi; Hiroshi Haga; Hideki Asada; Hiroshi Hayama; Naruaki Takada; Kenji Sera; Hiroyuki Uchida

A DC-DC converter composed of charge pumps and regulators has been integrated into a poly-Si TFT LCD that also contains a 6-bit DAC. It has the ability to supply regulated voltages to the 6-bit DAC and to the LCDs gate driver circuit.


ieee international magnetics conference | 1999

Highly defined narrow track write heads fabricated by focused ion beam trimming with the Al/sub 2/O/sub 3/ refilling process

Tsutomu Ishi; Yoshihiro Nonaka; T. Matsubara; Nobuyuki Ishiwata

We have developed a focused ion beam trimmed write head using Al/sub 2/O/sub 3/ refilling, in which an Al/sub 2/O/sub 3/ film was deposited and a two-step lapping process was performed after FIB trimming at the air bearing surface. This process provided highly defined pole edges without any rounded corners, well-filled hollows, and a damage-free read element. Good environment-proof characteristics were also obtained, because a diamond-like carbon film was deposited as a protective layer on the element after FIB trimming. The fabricated head showed good overwrite characteristics in half-micron width writing.


SID Symposium Digest of Technical Papers | 2007

46.3: DRAM‐Frame‐Memory Embedded SOG‐LCD

Hiroshi Haga; Yoshihiro Nonaka; Youichiro Kamon; Youich Kitagishi; Masayuki Jumonji; Kenichi Takatori; Hideki Asada

An SOG-LCD with integrated 230kb DRAM frame memory has been demonstrated. To achieve this dense integration, a memory system architecture for horizontal stripe was developed. Memory tests proved a 1MHz operation and retention time of 166ms. Fine images are displayed both in still images and moving pictures.


SID Symposium Digest of Technical Papers | 2005

24.4: A 510-Kb SOG-DRAM for Frame-Memory-Integrated Displays

Hiroshi Haga; Yoshihiro Nonaka; Youichi Kitagishi; Youichiro Kamon; Tadahiro Matsuzaki; Yoshinobu Sato; Hideki Asada; Tomohiko Otose; Daigo Sasaki

A system-on-glass (SOG) DRAM intended for integrated frame-memories of 262k-color QCIF+ displays has been developed. An integrated codec circuit reduces the number of memory cells and layout area by a factor of 2/3. By combining the SOG-DRAM, which has a data retention time of over 16.6 ms, with an embedded controller that enables simultaneous access for writing and reading, a frame-memory has been created. The operation was verified by chip measurement and demonstration.


SID Symposium Digest of Technical Papers | 2008

62.3: A Non‐Rectangular Heart‐Shaped SOG‐LCD

Yoshihiro Nonaka; Jiro Yanase; Hitoshi Yoshida; Kenichi Takatori; Koji Shigemura; Hideki Asada

A non-rectangular SOG-LCD has been developed by a well-polished system-integration technology including an arrangement in space. Driver circuits integrated along with curved sides of a heart-shaped screen with a hollow and an array of pixels slanting 45 degrees offer narrow bezels of less than 2 mm.


Archive | 2003

Charge pump-type booster circuit

Yoshihiro Nonaka


Archive | 2000

Magnetic head, method for making the same and magnetic recording/reproducing device using the same

Hiroaki Honjo; Nobuyuki Ishiwata; Tsutomu Ishi; Mikiko Saito; Shinsaku Saito; Tamaki Toba; Yoshihiro Nonaka

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