Sony Precision Technology Inc.

Sony Manufacturing Systems Corporation

Mitsuru Ohno

Masaaki Kusumi

Michio Okano

Shigeru Ishimoto

Yasuo Nekado

Gunichi Nakamura

Tomoyuki Nakada

Teruyuki Miura

Hideki Nakamori

Yoshihiko Ohkawara

Touru Sumiya

Akitaka Tsunogae

In a magnetic sensor () including a substrate () having a magnetism-sensitive element () formed thereon, a hard membrane () is formed on the outermost surface, an organic film () to relieve the stress caused by the hard membrane () is formed under the hard membrane (), and an inorganic film () to relieve the stress caused by the organic film () is formed between the organic film () and magnetism-sensitive element (). Also, an intermediate film formed from an element having a large force of bonding to carbon may be formed between the organic film () and hard membrane (). Thus, the magnetic sensor (MR sensor, for example) can be protected against an external shock.

Magnetic sensor and position detector

In a scale device including a case member () having a guide opening () formed therein, seal lip members (A,B), a carrier unit () having seal lip pressing means () formed thereon, and a coupling member () which slides inside and relative to the guide opening (), the seal lip members (A,B) are pressed at end portions () thereof by the seal lip pressing means () in the vicinity of opposite end portions () of the coupling member () to prevent the seal lip members (A,B) from being spread. Thus, any gaps can be prevented from taking place between the seal lip members (A,B) and coupling member () in the vicinity of the opposite end portions () of the latter. Therefore, dust or the like can be prevented from entering the case member ().

Scale device including means for preventing the occurence of small gaps between opposing walls of a guide opening

In a scale device including a scale unit () and detector (), the scale unit () includes a scale member () formed from a long material and having at least a pair of fixing holes () formed therein across a position signal carrying area () defined thereon and which carries position signals, and a case member () housing the scale member () therein and having formed therein a pair of fixing holes () through which there is inserted a fastening member () to be screwed into a mounting hole () formed in a stationary part () of a machine to which the scale device is to be installed. The detector () is fixed to a moving part () of the machine, which moves relative to the stationary part (), and includes a sensor () which moves oppositely to the position signal carrying area () on the scale member (). The scale unit () is fixed to the stationary part () with the scale member () and case member () being fastened together by the fastening member (). Thus, the scale member () different in linear expansion coefficient from the stationary part () can be installed to the latter with a high precision, and the scale device can make a measurement with a high accuracy, independently of environmental conditions.

Scale device

A position transducer capable of accurately detecting an n-bit code by a small number of ABS detectors when there is provided one ABS track. In an ABS head, the ABS detectors to are disposed for a distance &lgr; between the first ABS detector and (n&plus;m)th ABS detector to satisfy a requirement (n&minus;1)&lgr;&plus;2&dgr;<&lgr; and a distance &lgr; between two successive ones of the ABS detectors to satisfy a requirement 2&dgr;<&lgr; <&lgr;&minus;2&dgr;, so that at least one ABS detector is opposite to a stable area T in each of micro-areas at successive bits.

Position transducer

There is provided a position transducer ( ) capable of accurately detecting an n-bit code by n ABS detectors from one ABS track. When an INC value is under j or over k, signal output from each of the ABS detectors is binarized based on a threshold h and also based on a threshold l. First, an ABS value decider ( ) decides that a bit is &ldquo;H&rdquo; when it has been judged as being &ldquo;H&rdquo; on the basis of both the thresholds and a bit is &ldquo;L&rdquo; when it is has been judged as being &ldquo;L&rdquo; on the basis of both the thresholds. When the INC value is under j, a lower bit has the same code as that of the deiced bit. So, the ABS value decider ( ) decides that the lower bit is &ldquo;H&rdquo; or &ldquo;L&rdquo;. On the other hand, when the INC value is over k, an upper bit has the same code as the decided code. Thus, the ABS value decider ( ) decides that the upper bit is &ldquo;H&rdquo; or &ldquo;L&rdquo;. The ABS value decider ( ) decides a yet-to-decide bit to be &ldquo;L&rdquo; when a bit adjacent to the bit is &ldquo;H&rdquo;, and &ldquo;H&rdquo; when the adjacent bit is &ldquo;L&rdquo;.

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Kanagawa, Japan

Mitsuru Ohno