An electrostatic discharge (ESD) protecting transistor and a method for fabricating the same, capable of consuming a high voltage or overcurrent applied to a semiconductor circuit device and thereby protecting the circuit device from the high voltage or overcurrent. The ESD protecting transistor is of an asymmetric charge coupled MOS transistor structure having a highly doped buried layer capable of dispersing a current flux, thereby removing an instant ESD impact and reducing generation of heat caused by a concentration of high current flux. Accordingly, an effect of improving the resistance characteristic to the ESD impact is provided.

1. Field of the Invention
The present invention relates to electrostatic discharge (ESD) protecting circuit capable of consuming a high voltage or overcurrent applied to a semiconductor circuit device and thereby protecting the circuit device from the high voltage or overcurrent, and more particularly to a transistor of such an ESD protecting circuit comprising an asymmetric charge coupled MOS thick film transistor having a highly-doped buried layer, capable of improving the characteristic thereof and the resistance characteristic to an ESD impact.
2. Description of the Prior Art
As semiconductor devices have a higher integration degree, the resistance characteristic to ESD impact is degraded because of the use of a lightly doped drain (LDD) structure and a shallow junction and the use of titanium silicide (TiSi.sub.2). For fabrication of semiconductor devices of the next generation, however, it is required that there be improvements in resistance characteristics to ESD impact.
For satisfying such a requirement, there has been proposed an ESD protecting circuit adapted to protect an internal circuit of a semiconductor circuit device from an external ESD impact. FIG. 1 is a circuit diagram illustrating such an ESD protecting circuit.
As shown in FIG. 1, the ESD protecting circuit includes a first transistor 100 which is a thick film transistor adapted to be turned on when a positive ESD impact is applied to an input of the circuit device. At the turned-on state, the first transistor 100 provides a bypass for allowing the positive ESD impact to be bypassed without giving any damage to the internal circuit. The first transistor 100 has a threshold voltage of about 15V or greater. The ESD protecting circuit also includes a second transistor 200 which is a thin film transistor serving as a bypass for bypassing a negative ESD impact.
The present invention concerns the application of the first, thick film transistor of the above-mentioned ESD protecting circuit. As representative of conventional techniques about the above-mentioned application, there have been two known techniques which are illustrated in FIGS. 2 and 3, respectively.
In the case of FIG. 2, the traditional thick film transistor 100 includes doped source/drain contact regions (source/drain electrodes) 24 and a gate oxide layer 28. By this connection structure, an N type channel is formed in a portion of a P type substrate 21 disposed beneath the gate oxide layer 28, when a positive ESD impact is externally applied to the transistor 100. The N type channel serves as a bypass for bypassing the positive ESD impact. At this time, the thick film transistor 100 is operated in an inversion mode. As a result, the N type channel is formed on the upper surface of the P type substrate. This results in a limitation on the maximum channel width.
Consequently, the conventional technique has a drawback of limiting the maximum current discharged through the channel because electrons can flow (in the direction of arrow 30) only through the channel inverted. In other words, there is a limitation on removal of the ESD impact. Due to the residue of ESD impact over the limit, the ESD protecting circuit itself or the internal circuit of the circuit device may be damaged. As a result, the ESD protecting circuit may not achieve its protection function.
Furthermore, where a particular metal such as titanium silicide is used in fabrication of a highly integrated semiconductor device to reduce the metal-substrate contact resistance, the resistance characteristic to ESD impact is greatly reduced.
For solving the drawback encountered in the above-mentioned traditional thick transistor structure, the technique illustrated in FIG. 3 has been proposed which uses a thyristor.
The technique of FIG. 3 utilizes a rapid bipolar characteristic of the thyristor having a PNPN structure. In this case, complex process steps are additionally required for fabrication of the thyristor, even though a superior resistance characteristic to ESD impact is obtained.
For this reason, such a transistor employing the thyristor has seldom been used in the case of a mass-produced semiconductor devices.
In FIGS. 2 and 3, the reference numerals 22 and 32 denote gate oxide films, respectively, reference numerals 25 and 30 denote electrodes while the reference numerals 23, 33 denote insulating films, respectively. Also, the reference numeral 34 denotes a source/drain, 36 a well, 37 a p+ region and 38 a gate oxide layer.

Electrostatic discharge protecting transistor

Hyundai Electronics Industries Co., Ltd.


A power sanding machine (10) has three circumferentially spaced cogged belts (40) to drive three discs (52) rotatably mounted to an inner bowl (30) which is rotatably mounted to a housing (12), which in turn is connected to an operating handle (14). Mechanical lock can rotationally affix the inner bowl (30) to the housing to circumferentially position a pulley at the left or right edge (326, 322) of the sanding machine or at the front end (330) of the sanding machine. Power cleaning and sanding machines (412, 500, 600) incorporate the three disc (52) arrangement or a direct-drive one disc arrangement (572, 672). The machines (412, 500, 600) include multiple floor finishing units (420, 514, 614) ganged together in unique arrangements.

Hardwood floors have long been a desirable trait in a home and are also common in gymnasiums, bowling alleys, and ballrooms. However, sanding and refurbishing a hardwood floor is one of the more difficult do-it-yourself tasks for a homeowner or business owner.
There are at present two basic types of sanding machines on the market. Firstly, there is a drum sander that has a single large drum that retains a sheet of abrasive material thereon. The large drum aggressively sands the floor but much care and skill must be used in feathering the machine to avoid gouging of the floor. This type of drum is usually not recommended for the do-it yourself market.
Another type of machine is a disc sander. The present sanding machines on the market commonly have a single belt that drive all three sanding discs which creates a side torque that drives the machine to one side as it sands the floor. The operator then needs to always counter the torque that promotes an uneven surface finishing and fatigue on the operator for larger sanding jobs.
Many machines also have higher operating speeds that allow little error in operating the machines. The high operating speeds can quickly cause gouging and knicks in the wood floor without having time to control or eliminate these gouges. Furthermore, the high operating speeds produce significant amount of noise.
The disc sander machines are not as aggressive as the drum type machines. Attempts have been made to increase the sanding force of the discs by increasing the weight of the sander. These weights are obtrusive horseshoe shaped steel members that are mounted on top of the sander housing. The external weights require an extra fastening device and if not tightly mounting the weights, extra chatter and vibration may occur.
These sanding machines also have a housing edge that is widely spaced from the operating sanding discs. This prevents the machine to sand close to walls. Furthermore the housing may have a high periphery which prevents it from intruding under the toe recess under many kitchen cabinets. As a result, even after adding a shoe molding to the edge of the floor, an unsanded edge may be showing. Therefore, additional smaller edge sanders need to be extensively used to approach the edge of the floor which further make the sanding process difficult.
Furthermore, the sanding creates great amount of sawdust, which needs to be controlled. The sawdust if not controlled can fill the room creating a mess and interfering with the visibility of the floor as it is being sanded. Secondly, uncontrolled sawdust, particularly when air born, may under certain circumstances be combustible from sparks or other ignition sources. If a vacuum is difficult to use on a floor sander, complacency is promoted in allowing loose saw dust to accumulate.
Furthermore, for do-it-yourself applications, an operator often leases or rents a machine which therefore requires the operator to carry the machine from the rental outlet. If the machine is not easily disassembled to easily carried components, the weight of the machine may cause difficulty for the operator to transport the sander between the rental place and his home. Furthermore, the need to rent separate, aggressive drum sanders, disc sanders, and square buffers limits the marketplace. Any person attempting to sand a floor himself may become discouraged if too many different pieces of equipment are needed or if the length of the job is too long and difficult.
The drum sanders, orbital sanders, and square buff sanders not only make it difficult for the do-it-yourself person but also for rental outlets in that the market is relatively small and the rental outlet must store a plurality of specialized machines.
Moreover, large-scale floor refinishing projects can be expensive due to the time-consuming, labor-intensive techniques that exist today. Large-scale floor refinishing projects include resurfacing gymnasiums, bowling alleys, ballrooms, and the like. Such projects usually involve hundreds of hours of cleaning and sanding the floor with an individual floor finishing machine. Thus, a large-scale project can often take several days to several weeks to complete.
What is needed is a machine that with appropriate attachments can replace a drum sander, orbital sander, square buff sander, as well as a diamond grinder, scarifier, and carpet scrubber.
What is also needed is a floor sander that can be aggressive in order to accomplish a commonly sized residential job within a reasonable amount and also be safe enough to significantly reduce gouging of the floor. What is also needed is a floor sander that can approach an edge of a floor within the distance of an ordinary shoe molding while reducing noise, that increases control and ease of use, reduces saw dust, and provides other conveniences for making a do-it-yourself operation feasible.
What is likewise needed is an apparatus that enables relatively faster cleaning and sanding of a floor to reduce the labor hours required to finish a large-scale project.


An improved flash EEPROM with a sense amplifier having a sensing characteristics suitable for sensing a data signal under an externally applied supply voltage Vcc in a lower range, and a sense amplifier having a sensing characteristics suitable for sensing a data signal under the supply voltage Vcc in a higher range. A Vcc level detecting device detects in which range the supply voltage Vcc is in, soasto selectively enable one of sense amplifiers. Since the data signal is amplified using the sense amplifier having the optimum sensing characteristics in accordance with the level of the supply voltage, the stored data can be accurately read.

1. Field of the Invention
The present invention relates, generally, to semiconductor memory devices, and particularly to semiconductor memory devices capable of correct reading of stored data under a variable supply voltage. The invention is particularly applicable to nonvolatile semiconductor memories such as flash EEPROMs.
2. Description of the Background Art
In recent years, semiconductor memory devices have been used in various electronic equipments. Particularly, programmable EPROMs capable of erasing data, EEPROMs and flash EEPROMs have been known as nonvolatile semiconductor memories having floating gates. The flash EEPROM is one of a flash erasing type memory (i.e., is operable to electrically and simultaneously erase all bits of stored data), and can program the data byte by byte. Further, one memory transistor forms one memory cell, which enables high integration on a semiconductor substrate.
Many small electronic equipments using semiconductor memories are powered not only by external power supplies but also by internal power supplies, i.e., batteries. The power can be supplied selectively from the external power supplies and internal power supplies
Generally, externally supplied power has a stable voltage level, but an output voltage of a battery decreases as a discharging time elapses In other words, when the power is supplied by the battery, the supply voltage is variable Although the invention is generally applicable to various semiconductor memories, an example, in which the invention is applied to a flash EEPROM, will be described hereinafter.
FIG. 9 is a block diagram showing a background of the invention, and particularly showing a flash EEPROM. Referring to FIG. 9, an EEPROM 200 includes a memory cell array 1 provided with a large number of memory cells MC arranged in rows and columns, a row decoder 2 for selectively activating word lines Xl-Xm, a column decoder 3a for selecting a memory block (or region) to be accessed, a column decoder 3b for selecting a bit line to be accessed in the memory block, a sense amplifier 5 for amplifying a data signal, and an output buffer 6 for supplying output data D.sub.0. Although the circuit block for reading the data is shown in FIG. 9, it should be noted that flash EEPROM 200 comprises a circuit block for writing the data, not shown.
In the reading operation, row decoder 2 decodes an externally applied row address signal (not shown) to activate selectively one of word lines Xl-Xm. Memory cell MC connected to the activated word line grounds bit lines BLl-BLn in accordance with the stored data signal Each memory cell MC is turned on or off in response to the stored data signal. Therefore, potentials of bit lines BLl-BLn are brought to a ground potential or a floating state in accordance with the data stored in the memory cell accessed by row decoder 2.
Column decoder 3a supplies block selecting signals YAl-YAi in response to an externally applied column address signal (not shown). NMOS transistors 6l-6i for selecting the blocks are selectively turned on in response to block selecting signals YAl-YAi, respectively. Column decoder 3b decodes the externally applied column address signal (not shown) to supply column selecting signals YBl-YBn. NMOS transistors 9l-9n for selecting the column are selectively turned on in response to column selecting signals YBl-YBn, respectively.
Therefore, the potential of one bit line selected by column decoder 3b, i.e., the read data signal is transmitted from the memory block selected by column decoder 3a to sense amplifier 5. Sense amplifier 5 amplifies the transmitted data signal, and the amplified data signal is supplied as output data D.sub.0 from output buffer 6.
FIG. 10 is a circuit diagram of sense amplifier 5 shown in FIG. 9. Referring to FIG. 10, sense amplifier 5 includes PMOS transistors 21, 22 and 23 as well as NMOS transistors 24, 25 and 26. Transistors 21, 22 and 23 have their gates grounded. Transistor 24 has a gate connected to a signal line 27. Transistors 22 and 25 are connected in series between power supply potential Vcc and signal line 27. Transistors 23 and 26 are connected in series between supply potential Vcc and signal line 27. Signal line 27 corresponds to signal line 27 shown in FIG. 9. Amplified signal SA.sub.5 is supplied through a common connection node of transistors 23 and 26.
Then, an operation of sense amplifier 5 for reading the data will be described below. First, a case will be described in which the data stored in the memory cell MC designated by row decoder 2 and column decoders 3a and 3b is "1". It is also assumed that the memory transistor forming the memory cell MC is turned on in this case. Therefore, the potential at input node N3 in sense amplifier 5 lowers, and thus transistor 24 is turned off. Thereby, the potential at node N2 rises, so that transistors 25 and 26 are turned on. Owing to the turn-on of transistors 25 and 26, the potential of node N3 is maintained at a level which is not very low. Consequently, amplified signal SA.sub.5 at the low level is supplied through output node N1.
In the foregoing operation, it is noted that transistor 25 operates to prevent excessive lowering of the potential of input node N3. If the potential of input node N3 is excessively lowered, the rising of the potential of the bit line would be delayed when the data signal at the inverted level (i.e., the high level in the above case) were read in the next read cycle. Therefore, it is noted that transistor 25 contributes to reduce the time required for reading the data.
When the memory cell MC designated by row decoder 2 and column decoders 3a and 3b stores "0", the designated memory cell MC is turned off. Therefore, the potential of input node N3 in sense amplifier 5 has the high level, and thus transistor 24 is turned on. Thereby, the potential of node N2 has the low level, and thus transistors 25 and 26 are turned off. Consequently, excessive increase of the potential of input node N3 is prevented. In this case, amplified signal SA.sub.5 at the high level is supplied through output node N1.
FIG. 11 is a diagram showing transition of an output voltage of sense amplifier 5 under variable supply voltage Vcc. Referring to FIG. 11, the abscissa represents the change of the supply voltage Vcc and the ordinate represents the change of the output voltage of sense amplifier 5. Referring to FIG. 11, when the data read from the memory cell is "0", sense amplifier 5 supplies the output voltage indicated by line SA.sub.50. When the memory cell stores the data of "1", sense amplifier 5 supplies the output voltage indicated by line SA.sub.51. As shown in FIG. 11, output voltage SA.sub.50 for the data of "0" and output voltage SA.sub.51 for the data of "1" changes as the supply voltage Vcc changes.
Further, line Vth in FIG. 11 indicates the change of threshold voltage of a circuit at the succeeding stage (e.g., output buffer 6 shown in FIG. 9) connected to the output of the sense amplifier 5. Line Vth indicates the threshold voltage of a circuit such as an inverter, which receives the output voltage of sense amplifier 5.
Flash EEPROM 200 is designed to operate properly under the fixed supply voltage Vcc. Specifically, sense amplifier 5 is designed to correctly sense the data signal supplied from the memory cell under the fixed supply voltage, e.g., Vcc of 5 V. In other words, conventional sense amplifier 5 supplies output data signals SA.sub.50 and SA.sub.51 suitable to threshold voltage Vth of the circuit connected in the succeeding stage when the fixed supply voltage (Vcc=5 V) is supplied.
Accordingly, when the electronic equipment receives the supply voltage from the battery, i.e., internal power supply, the output voltage of the battery gradually reduces as the discharging time of the battery elapses. This means that the supply voltage Vcc supplied to the semiconductor memory gradually reduces. As can be understood from FIG. 11, output voltages SA.sub.50 and SA.sub.51 of sense amplifier 5 and threshold constant voltage Vth of the circuit at the succeeding stage are designed to be optimum under the supply voltage Vcc of 5 V supplied thereto. In other words, they are designed to perform the correct data reading operation under the supply voltage of 5 V. Due to the lowering of supply voltage Vcc, a relation between output voltages SA.sub.50 and SA.sub.51 of sense amplifier 5 and threshold constant voltage Vth of the circuit in the succeeding stage changes in a direction indicated by an arrow AR in FIG. 11, so that the optimum relationship for the data reading is destroyed. Particularly, in a case that supply voltage Vcc lowers approximately below 3 V, all output voltages SA.sub.50 and SA.sub.51 exceed threshold voltage Vth. This means that all data is read as "0" under such supply voltage Vcc. In other words, lowering of supply voltage Vcc causes error in the data reading operation.
In order to avoid the above problems, there may be additionally provided other semiconductor memories which are provided with sense amplifiers having the optimum sensing characteristics under the supply voltage Vcc of 3 V. However, this increases the number of semiconductor devices used in the small electronic equipment, which is not preferred in view of the space and cost.

Semiconductor memory device capable of correct reading of data under variable supply voltage


An identification circuit (131) recognizes optical probes (112A, 112B) of different scanning types that are connected to a light source unit (113) and a control device (114), the frequency of the drive signal of a control circuit (130) for driving a scanner inside the optical probe is varied by this recognition signal, corresponding drive signals are applied to the optical probes connected, the scanner of each probe is scanned, and two-dimensional optical information is imaged by an imaging device (115) and displayed on a monitor (116).

Optical scanning probe devices have been developed in recent years with which optical information about an examination site is obtained by transmitting light generated by a light source device through an optical fiber, emitting this light from the tip of the optical fiber and shining it on the examination site, and scanning the focal position back and forth.
A conventional example of this is U.S. Pat. No. 5,120,953.
This conventional example discloses an endoscope that gives an enlarged view of the tissue at the examination site. This conventional example also discloses the technique of scanning the tip of an optical fiber with an actuator, and scanning the focal point with a condensing lens disposed in front of this actuator. The scanning of a focal point with a scanning mirror has also been disclosed in U.S. Pat. No. 5,742,419.
However, when optical fiber scanning is performed by scanning the optical fiber tip end with respect to the lens, the optical fiber, which is disposed along the optical axis of the lens, deviates from this optical axis, making it difficult to achieve high resolution.
Accordingly, the present applicant proposed an optical fiber and (object) lens scanning type of optical scanning probe with which the (object) lens is scanned along with the optical fiber tip in such a case.
With this type, the optical fiber tip disposed along the optical axis of the lens does not deviate in its relative position from the lens when scanned, so in principle the aperture number can be larger and higher resolution is possible.
On the other hand, because optical fiber and lens scanning requires the scanning of both the optical fiber tip and the lens with an optical fiber and lens scanning type of optical scanning probe, an optical fiber scanning type is advantageous in that faster scanning is possible.
Accordingly, when this apparatus is used inside the body, for example, if an optical fiber scanning type can be used if the site being observed is one that moves, such as the heart, and if an optical fiber and lens scanning type, which affords higher resolution, can be used if the site being observed does not move, then the resulting system will be extremely convenient.
The present invention was conceived in light of the above situation, and it is an object thereof to provide an optical scanning probe system with which it is possible to use the optical scanning probe best suited to the site being examined.
Another object is to provide an optical scanning probe with which higher resolution can be obtained.


A method for transmitting beacons by nodes in a multi-tier wireless local area network is disclosed. First, a first beacon by a tier 1 node in the multi-tier wireless local area network is transmitted. Then, a second beacon by a tier 2 node is transmitted where the second beacon is transmitted based upon the time that the first beacon is sent by the tier 1 node.

Beacons are packets transmitted in a wireless local area network (WLAN) to communicate information about the WLAN and to communicate information about the capabilities of the sender. In general, IEEE standards relating to WLANs define how beacons may be transmitted in a single-tier WLAN but do not adequately address multi-tier WLANs. Further, the IEEE standards address how each individual node in the WLAN transmits a beacon without considering the relationship of beacons being transmitted by a number of nodes. Thus, there is not much synchronization between multiple nodes transmitting beacons. Because there is not much synchronization of multiple nodes transmitting beacons, nodes in a multi-tier WLAN may spend a lot of time performing a scan of neighbors, may not efficiently receive traffic, and may ultimately not see neighboring nodes. Because of this lack of synchronization, nodes in a multi-tier WLAN may consume unnecessary power and waste unnecessary capacity. Accordingly, there exists a need for an improved method of propagating beacons in a wireless local area network.
It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements are exaggerated relative to each other. Further, where considered appropriate, reference numerals have been repeated among the figures to indicate identical elements.

Multi-tier WLAN and method for propagating beacons in a multi-tier WLAN thereof


A jaw for a bar clamp having a trigger pivoted to a handle at a position on the handle that is spaced from the bar. The trigger directly contacting a drive lever at a contact point, such that the contact point between the trigger and the drive lever changes along the length of the drive lever as the trigger pivots with respect to the handle such that when the contact point is remote from the bar the trigger provides high mechanical advantage to the drive lever, and when the contact point is closer to the bar the trigger provides low mechanical advantage to the drive lever. Also, a method of using a bar clamp, including positioning first and second moving jaws on opposite sides of a member to be clamped and activating a mechanical motor to move the bar and force the first moving jaw toward the second moving jaw until both the first and second moving jaws securely clamp the first member to be clamped between the first and second moving jaws.

Known adjustable clamps include one moving jaw and one fixed jaw. U.S. Pat. No. 6,386,530 to Marks, U.S. Pat. No. 6,474,632 to Liou, U.S. Pat. No. 5,005,449 to Sorensen, U.S. Pat. No. 5,443,246 to Peterson, U.S. Pat. No. 5,265,854 to Whiteford, U.S. Pat. No. 5,853,168 to Drake, and U.S. Pat. No. 5,666,964 to Meilus, and U.S. Patent Application Publication Nos. 2003/0090048 to Verzino et al.; and 2004/0140602 to Gerritsen et al., which disclose various clamps, are each incorporated herein in its entirety by reference thereto, respectively.

Adjustable clamp and method of using an adjustable clamp


A wire electrical feeding device for an electrical discharge machine. Vibrator assemblies are utilized to feed the wire electrode through electrode guides of the electrical discharge machine. A first vibrator assembly vibrates through a locus which includes a component in the wire feeding direction. The wire electrode is selectively pressed against the first vibrator assembly when the first vibrator assembly is moving in a direction having a component in a wire feeding direction. In the alternative, a second vibrator assembly, which is coupled to the first, clamps the wire electrode when the first vibrator assembly is moving in a direction having a component in the wire feeding direction. The vibrator assembles may each be driven at different vibrational frequencies.

1. Field of the Invention
The present invention relates to a wire electrode feeder for a wirecut electrical discharge machine.
2. Description of the Related Art
FIG. 23 illustrates the arrangement of a conventional wire electrode feeder disclosed in, for example, Japanese Patent Publication No. 31333 of 1988, wherein a workpiece 1 has a starting hole 2 pre-drilled at a machining start point. A wire electrode 11 is continuously provided to the work piece by a supply motor 3, via a supply pulley 4 coupled with the supply motor 3, and a clamp pulley 5 disposed opposite to the supply pulley 4. A first link 6 is extended to the clamp pulley 5, and a second link 7 is coupled to the end of the first link 6, the second link being pivotally moveable about support pin 8. A coil spring 9 is disposed between the second link 7 and an external fixture. A solenoid 10 is coupled with the end of the second link 7 which is opposite to the side thereof which is coupled to the coil spring 9. The wire electrode 11 is supplied through a wire electrode guide pipe 12, having a die-shaped upper wire electrode guide 13 made of diamonds. A sintered metal portion 14 is disposed on the lower end of guide pipe 12 for holding the upper wire electrode guide 13 to the lower end of the guide pipe 12. There also is a die-shaped lower wire electrode guide 15 that is made of diamonds and is held by a sintered metal portion 16 and set in a lower guide body 17. A pair of take-up rollers 18a and 18b are disposed opposite to each other with the wire electrode 11 therebetween, and a take-up motor 19 is coupled with the take-up roller 18b.
The operation of the wire electrode feeder shown in FIG. 23 will now be described. The workpiece 1 is placed on a work table (not shown) that is freely movable within a horizontal plane according to control commands. At the beginning of machining, the workpiece 1 is first set so that the starting hole 2, pre-drilled therein, is coaxial with the guide pipe 12. The clamp pulley 5 is then released by the restoring force of the coil spring 9. In this state, the wire electrode 11 is inserted from the top into the groove of the wire supply pulley 4. The solenoid 10 is then activated to press the clamp pulley 5 against the wire supply pulley 4 and the wire supply motor 3 is driven to feed the wire electrode 11 through the guide pipe 12 in the direction of the upper wire electrode guide 13. Since the upper wire electrode guide 13 and lower wire electrode guide 15 are supported to be coaxial with each other by a holding mechanism (not shown) at the beginning of machining, the wire electrode 11 passes through the upper wire electrode guide 13 and the lower wire electrode guide 15 and is inserted between the pair of take-up rollers 18a and 18b. In this state, the take-up rollers 18a, 18b and take-up motor 19 are ready to feed the wire electrode 11, and the clamp pulley 5 is released by energizing solenoid 10. The guide pipe 12 is then raised and removed from within the workpiece 1 by a moving mechanism (not shown), and the wire electrode 11 is thus inserted, under tension, in the workpiece 1.
To facilitate the above-described operation, the leading edge of the wire electrode 11 is reshaped by cut-off reshaping means (not shown) into a tapered shape so as to easily penetrate into the die-shaped upper and lower wire electrode guides 13, 15.
FIG. 24 illustrates an alternative conventional wire electrode feeder employing a supersonic vibrator used as a wire feed driving source to feed a wire electrode.
In this conventional device, first, a wire electrode 11 is inserted into the wire electrode guide 101 and a starting hole (not shown) provided beforehand in a workpiece 1. Subsequently, a presser plate 109 is released from a supersonic vibrator 106 by a releasing mechanism (not shown). The wire electrode 11 is led to a gap between the presser plate 109 and the supersonic vibrator 106, and the presser plate 109 releasing mechanism is reset to force the wire electrode 11 to be pressed against the supersonic vibrator 106 by the preload spring 108.
On completion of the wire electrode 11 stretching operation as described above, two free ends of the elastic body 104, are caused to each resonate in a flexure oscillating secondary mode and a vertical oscillation primary mode due to piezo-electric devices 105a, 105b. By causing the two modes to be 90.degree. out of phase, both ends of the elastic body 104 are made to vibrate, on elliptical locuses in an identical direction of rotation, friction-driving the wire electrode 11 in a predetermined direction. The elastic body 104 included in the supersonic vibrator 106 is designed so that the two vibration modes have an identical resonant frequency and so that the vibration frequency is equal to the resonant frequency so as to cause a standing wave.
Also, in the conventional wire electrode feeder arranged as described above, the wire must be fed between the wire supply pulley 4 and clamp pulley 5 by the wire supply motor until it passes through the workpiece and reaches the take-up rollers, or supersonic vibrator. Accordingly, the wire electrode may tend to curl due to a slight speed and/or mounting position difference between the two pulleys. Also, the wire may buckle midway in the feeding path from the supply pulley to the electrode guide before the wire electrode passes the electrode guide.
Further, in the second conventional device wherein the wire electrode driving source comprises the supersonic vibrator, the wire electrode cannot be fed through the workpiece automatically, and after the wire electrode has been fed therethrough, friction, which tends to prevent the wire electrode from being driven is generated between the presser plate and wire electrode which are continuously pressed against the vibrator, and further since the vibrator and presser plate are of a flat shape, the wire electrode may be deformed or forced out of position.

Wire electrode feeder for wirecut electrical discharge machine


This invention relates to a photo-polymerization type photosensitive electrode paste composition for a plasma display panel that is capable of preventing a bubble from occurring on an electrode surface during an electrode paste printing process and a damage of an electrode pattern caused by adhesive strength reduction, and a method of fabricating the electrode using the same.

1. Field of the Invention
This invention relates to a plasma display panel, and more particularly to a photo-polymerization type photosensitive electrode paste composition for a plasma display panel that is capable of preventing a bubble from occurring on an electrode surface during an electrode paste printing process and a damage of an electrode pattern caused by adhesive strength reduction, and a method of fabricating the electrode using the same.
2. Description of the Related Art
Recently, a plasma display panel PDP as a flat panel display device has attracted attention for its easy manufacture in a large size. The PDP uses the phenomenon that a vacuum ultraviolet ray, which has a wavelength of approx. 147 nm emitted from the plasma occurring upon the discharge of inert gases, collides with a fluorescent film to be converted to red, green and blue lights of visible ray. Accordingly, the PDP is capable of displaying full colors, has a rapid response speed and has a wide-viewing angle to make easy realization of a large size display device of which the size is larger than 40 inches so that it attracts attention as one of next generation display devices such as high definition television HDTV etc.
The PDP normally displays a picture by controlling each discharge period of the pixels in accordance with digital video data. In such PDP is typical an alternating type PDP which has three electrodes as shown in FIG. 1 and is driven by an alternating current.
FIG. 1 is a diagram representing a cell structure arranged in the alternating type PDP with the type of matrix.
Referring to FIG. 1, the PDP cell includes an upper plate with a pair of sustaining electrodes 14 and 16, an upper dielectric layer 18 and a protective film 20 that are sequentially formed on an upper substrate 10, a lower plate with an address electrode 22, a lower dielectric layer 24, a barrier rib 26 and a fluorescent layer 28 that are sequentially formed on a lower substrate 12.
The upper substrate 10 and the lower substrate 12 are separated parallel to each other by the barrier rib 26.
Each sustaining electrode pair 14 and 16 includes a transparent electrode 14A and 16A with a relatively broad width and made of transparent electrode material ITO for transmitting visual ray, and a bus electrode 14B and 16B with a relatively narrow width and for compensating the resistance components of the transparent electrode 14A and 16A. Any one of the sustaining electrode pair 14 and 16 plays role of the scanning electrode and another one of the sustaining electrode pair 14 and 16 plays role of the sustaining electrode. The scanning electrode 14 is mainly supplied the scanning signal for the panel scanning and the sustaining signal for keeping the state of discharge. And the sustaining signal is mainly supplied to the sustaining electrode 16.
The wall electric charge, formed upon discharge, is accumulated on the upper dielectric layer 18 and the lower dielectric layer 24. The protective film 20 prevents the damage of the upper dielectric layer 18 by sputtering so as to increase the life of the PDP and to increase the efficiency of emission of the second electron. Magnesium oxide MgO is generally used for the protective film 30.
An address electrode 22 is formed in the direction of crossing the pair of sustaining electrodes 14 and 16. Data signals are supplied to the address electrode 22 for selecting cells to be displayed. The barrier rib 26 is formed parallel to the address electrode 22 and prevents the ultraviolet ray generated by the discharge from being exposed to the adjacent cells. The fluorescent layer 28 is spread on the surface of the barrier rib 26 and the lower dielectric layer 24 and generates one of visual rays among red, green and blue colors. And, inert gas for the gas discharge is injected into the discharge space thereinside.
The bus electrode 14B and 16B of the upper substrate 10 in such a PDP is formed to prevent a voltage drop of the transparent electrodes 14A and 16A, which are formed of Indium Tin Oxide ITO. Because the bus electrodes 14B and 16B shields the light emission to deteriorate brightness of PDP, it is necessary to be as narrow as possible within the limit where the required line resistance is acquired. The bus electrodes 14B and 16B are mainly formed by the vacuum deposition and etching process in the three-layered structure of chromium/copper/chromium. However, the forming method of the bus electrodes 14B and 16B of the three-layered structure of chromium/copper/chromium by the vacuum deposition has some problems that its processing time is long, the thin film forming device and material thereof is high in price and the environment can be contaminated upon etching.
Also, the address electrode 22 is formed by printing method in use of silver paste mainly. But, when forming the electrode by using the paste for printing, the pitch precision of the electrode and the electrode width gets very hard to control. In other words, the spread property becomes deteriorated upon the electrode print, and the adhesive strength to the glass substrate becomes decreased thereby having its resolution deteriorated.
Accordingly, there is required a new PDP electrode forming method which has less loss of the material and is appropriate to high precision by using a photolithography that is capable of forming a minute line width.

Photo-polymerization type photo-sensitive electrode paste composition for plasma display panel and fabricating method thereof

Abstract: A photo-polymerization type photo-sensitive electrode paste composition for a PDP according to the present invention includes a binder polymer for increasing viscosity; at least one of a multi-functional monomer and a multi-functional oligomer that are combined in the shape of chain in reaction to a radical; metal powder; a frit glass for gluing the metal powder; and a photo-initiator and solvent for generating the radical in reaction to a light.


A method for monitoring welding of a workpiece includes selecting light of a predetermined wavelength from that emitted by plasma produced by the welding process, generating signals indicative of the selected light's intensity, and correlating those signals with the cross-sectional area of the weld. An apparatus for monitoring welding of a workpiece includes a filter for passing selected light of a predetermined wavelength emitted by plasma, a signal generator which produces signals indicative of the intensity of the selected light, and means for correlating the signals with the weld's cross-sectional area.

Since the laser's inception, it has gained increasing acceptance in the industrial market as being a manufacturing tool that can increase efficiency and improve quality. The laser's increasing acceptance is due, in large part, to: its noncontact operational characteristic which eliminates costly fixturing; its easy automation and integration into manufacturing processes; its potential for greatly reducing process times; and its ability to access remote locations and be shared by several workstations for multiple processing. High power lasers are now being used in industry for a number of manufacturing applications including boring, cutting, welding, heat treating, and general machining.
Weld quality is a primary concern in industrial laser welding processes. Since many process variables can influence the quality of a laser weld (such as power, frequency, weld speed, focal length, position, workpiece composition, joint fit up, and shield gas), it is necessary to be able to determine the penetration of the weld independent of such process variables. Penetration of a weld is, probably, the single most important indicia of weld quality with a measure of same being required to permit adjustment of the process variables. By using appropriate process controls in which one or more of the aforementioned process variables are adjusted, the quality of the weld may be maintained within predetermined limits. The welding process can be monitored and controlled effectively if at least one measurable output can be related to the physical process of welding. Many process monitoring devices have been used for laser weld processed materials without notable success.
A method and apparatus for monitoring laser beam welding, illustrated in U.S. Pat. No. 5,155,329 issued Oct. 13, 1992, generally involves monitoring the intensity of light of predetermined wavelength emanating from a workpiece immediately before there is a rise in the intensity of an associated pulsating laser beam and correlating the emanating minimum light intensity with the depth of penetration of the laser weld zone. Since the weld depth of penetration is correlatable with the minimum intensity of emanating light prior to a rise in the intensity of the pulsating laser beam, the pulsating laser beam's intensity must be monitored as well as the emanating light intensity of the predetermined wave length. Accordingly, such method and apparatus involve a degree of complexity which is undesirable.
The present invention is directed to overcoming one or more of the problems set forth above.

Method and apparatus for monitoring weld quality


A chromosomal gene of Borrelia burgdorferi which encodes a conserved antigen of approximately 79 kD has been isolated and sequenced. The chromosomal gene, the gene product, and antibodies to the gene product may be used in diagnostic methods for the detection of Borrelia burgdorferi infection. The antigen and fragments thereof are suitable for use in vaccine compositions and methods.

1. Field of the Invention
Lyme disease was first described in the late 1970's as a unique grouping of arthritic symptoms in patients from Lyme, Connecticut. Subsequent investigation demonstrated that the disease is caused by infection with Borrelia burgdorferi, a spirochete, following exposure to deer (ixodid) ticks. It is now known that lyme disease in humans is a multi-systemic disorder characterized by dermatologic, rheumatologic, cardiac, and neurologic manifestations.
While several isolates of B. burgdorferi from North America and Europe have been characterized at both the genetic and antigenic level, the unequivocal diagnosis of lyme disease remains problematic. Isolation and cultivation of borrelia from infected patients is difficult and not practical for routine diagnosis. Immunological and genetic detection methods have not become generally available, at least in part because the known major antigens of B. burgdorferi have previously been thought to be coded on linear plasmid and have demonstrated significant antigenic variation with regard to the level of expression and molecular weight. There have also been reports of serological cross-reactivity with related human pathogens, such as B. hermsii (the causative agent of tick-born relapsing fever) and Treponema pallidum (the causative agent of syphilis).
It would therefore be desirable to provide improved methods for diagnosing lyme disease and in particular for unequivocally determining the presence of B. burgdorferi in patient samples. To provide such methods, it would be desirable to identify genetic and antigenic information which is widely conserved among B. burgdorferi strains and which can be used in a variety of detection protocols. More specifically, it would be desirable to identify a conserved chromosomal gene which encodes a major antigenic protein, where the gene can serve as the basis for genetic screening assays and the antigen can serve as the basis for immunologic screening assays.
2. Description of the Background Art
Immunochemical analyses of B. burgdorferi have revealed the presence of several immunodominant antigens that are recognized during the described stages of human infection. (Craft, et al. (1986). Clin. Invest. 78:934-938; Grodzicki, et al. (1988) J. Infect. Dis. 157:790-797; Nadal, et al. (1989) Pediatr. Res. 26:377-382) One of the immunodominant antigens was reported to have a molecular weight of approximately 83 kD. No description or characterization of the gene encoding this antigen had been reported prior to the work which is the subject of the present application. The data included in the Experimental section hereinafter was reported in LeFebvre et al. (1990) J. Clin. Microbiol. 28:1673-1675 and in Perng et al. (1991) Infect. Immun. 59:2070-2074.

Methods and compositions for diagnosing lyme disease

The Regents of the University of California


A position sensor detects a position of an objective lens for irradiating light onto an optical disk. An output adjustment of the position sensor is used for correcting characteristics change due the change with the passage of time. The position of an objective lens and the output of a position sensor are measured at a reference time, the ratio at the neutral point is determined in advance, and when the device is used, the position of the objective lens and the output of the position sensor are measured. The output level at the neutral point during using the device is calculated from the measurement result and the ratio at the neutral point.

1. Field of the Invention
The present invention relates to an output adjustment method for a lens position sensor of an optical disk device for adjusting the output of the lens position sensor that detects a position of an object lens of the optical head, and the optical disk device, and more particularly to an output adjustment method for a lens position sensor of an optical disk device that detects a neutral point accurately even if the output of the lens position sensor changes due to the change with the passage time of the lens position sensor, and the optical disk device thereof.
2. Description of the Related Art
Because of advancements in optical storage technology, optical disk devices using optical storage disks are widely used for compact disk (CD) devices, DVD (Digital Versatile Disk) devices, magneto-optical (MO) disk drives and others.
As FIG. 21 shows, in such an optical disk device, light is irradiated from an optical head 2000 onto an optical disk 1000, and a reflected light thereof is received by an optical detector 2030 for reading. And the focus position shift FES of the irradiated light and the track position shift TES are also detected from the reflected light.
In other words, spiral or concentric tracks have been formed on the optical disk 1000, and it is effective for fine reading and writing to focus the irradiated light on the recording face of the disk and position the light to the track position of the disk.
For this, the focus control mechanism for controlling the focus of the objective lens 2010 of the optical head 2000, according to the detected focus position shift and the track control mechanism 2020 for controlling the objective lens 2010 to position the track position, according to the detected track position shift, are provided.
To control the lens position, the lens position sensor 2040 is installed on the lens 2010, and the signal LPOS, according to the displacement of the lens 2010, is acquired from the lens position sensor 2040, and the lens position is controlled based on the signal LPOS.
The lens position signal LPOS is used for locking so that the lens 2010 does not sway during seeking, and for removing the offset of the track position shift (error) signal.
As FIG. 23 shows, when the positional relationship of the optical head 2000 and the objective lens 2010 is not shifted, the relationship of the TES amplitude waveform and tracking position is expressed by a TES amplitude waveform having a symmetric sine wave of which center is the zero level (tracking position) indicated by the straight line. Since the center position of the TES waveform is exactly at the tracking position, a fine track servo can be implemented.
If the positional relationship between the optical head 2000 and lens 2010 shifts, however, offset is generated in the TES amplitude., and a shift occurs, as shown in FIG. 24. In the case of FIG. 24, the track servo is executed at the edge of the TES waveform, which makes the track servo unstable.
In this way, when the positional relationship of the optical head 2000 and lens 2010 shifts, this must be corrected, so the lens position is detected by the above mentioned lens position signal LPOS, and the offset of TES is corrected.
In this method of detecting the lens position, an error may be generated due to the change of the passage time and contamination of the sensor 2040, for example. In other words, as FIG. 22 shows, the lens shift amount and the output of the lens position sensor changes due to the change of the passage time, which makes it difficult to cancel the offset accurately.
To correct this change of output, a differential detection type has been proposed, where a pair of light receiving sections are provided to the lens position sensor 2040, so as to obtain the difference between the outputs of the pair of light receiving sections (e.g. Japanese Patent Application Laid-Open No. 7-235064).
A magneto-optical disk device, which is a type of optical disk device, is often used as a stationary type, so the position of the device rarely changes. However today magneto-optical disks are becoming compact, and are seen used in portable equipment fields. And if used as portable equipment, the attitude of the device when used is unknown.
If the attitude changes, the objective lens, which is supported such that moving in the track position is possible, tends to cause a position shift between the lens position and optical head, due to gravity and other influences, and the amount of shift tends to increase.
If the differential detection type in prior art is used for correcting this, a pair of detection sections and a differential circuit must be installed, so it is not preferable to decrease cost and size for portable equipment, since the number of components increases and mechanical components become complicated.
Also considering the change of the passage time, the characteristics of the initial status change because the light intensity of the LED section of the sensor changes, or the light receiving sensitivity of the sensor changes due to dust which attaches to the detector section, for example. Therefore, if a pair of light receiving sections is installed, they do not always deteriorate in the same way, even if the differential type is used, and correction of the change of output may be difficult in some cases.

Output adjustment method for lens position sensor of optical disk device and optical disk device thereof


The present device relates to a slide assembly for a zipper, and a method for manufacturing a zipper slide assembly. The slide assembly is formed in a single die cast operation to include the slide member and the pull member being formed simultaneously. Portions of the bridge and pull member are formed to provide a first side to side angle of pull when the pull member cooperates with the first end of the bridge, and a second side to side angle of pull when the pull member cooperates with the second end of the bridge.

A zipper, zip, fly or zip fastener, formerly known as a clasp locker or slide fastener, is a commonly used device for binding the edges of an opening of fabric or other flexible material, like on a garment or a bag. It is used in clothing (e.g., jackets and jeans), luggage and other bags, sporting goods, camping gear, and other items.
The bulk of a zipper/zip consists of two rows of protruding teeth, which may be made to interdigitate, linking the rows, carrying from tens to hundreds of specially shaped metal or plastic teeth. These teeth can be either individual or shaped from a continuous coil, and are also referred to as elements. The slider is operated by hand, and moves along the rows of teeth. Inside the slider is a Y-shaped channel that meshes together or separates the opposing rows of teeth, depending on the direction of the slider's movement.
In general, a zipper represents a small amount of the overall cost of a product. However, if it fails, the entire garment or device may be unusable until the zipper is replaced or repaired. Problems often lie with the slider portion of the zipper. Sliders are typically made of a slide portion and a pull. The user grabs the pull, which is pivotally connected to the slide, and pushes or pulls the slide in one direction or the other to cause the slide to move. Movement of the slide causes the teeth to engage or disengage with each other as the movement occurs. Slides are typically manufactured to include one or more pieces to which the pull is later assembled. Assembly of the pull to the slide is usually accomplished by bending a bridge portion of the slide, which is die cast having a gap to create an interlocking engagement between the two components. Other methods require assembly of extra bridge components which may be bent, staked or otherwise secured to the slide. However, these constructions are weak and prone to breakage with repeated use, causing the pull to become separated from the slide.
It has been proposed in the past to form the slide and the pull in a single operation. However, the proposed methods, devices and resulting zipper products have been unable to be produced or are unacceptable to the industry when produced from metal. Producing a metal slider assembly with the pull interlocked with the bridge has proven to be extremely difficult due to the rigid properties of the metal, which makes tool retraction from around the formed part very difficult without modifying the geometry of the part in an undesirable manner.
For example, U.S. Pat. No. 2,736,062 to Scheuermann et al. discloses a method of molding a slide and pull together in a single operation. Scheuermann utilizes four slides that intersect at 45 degree angles with respect to each other. The slides intersect at the bridge and pull portions of the slider assembly with the pull positioned at a vertical right angle with respect to the top surface of the slide. However, this method, as shown in the drawings, requires the inner surfaces of the pull loop and the bridge to include 45 degree or similar angles that form sharp points along the inner surfaces. The sharp points cause stress risers in the part, and the sharp corners wear very quickly, causing any surface coatings to be worn away. This results in discoloration of the slide assembly, and often results in corrosion of the parts during a washing cycle. In addition, the modified geometry severely limits the movement of the pull within the bridge by reducing the space that the pull has to rotate and slide within the bridge.
U.S. Pat. No. 5,604,962 to Mayerhofer, U.S. Pat. No. 5,698,243 to Wakabayashi, U.S. Pat. No. 4,210,196 to Weiner, and U.K. Patent No 2,220,608 to Liso all show variations of the Scheuermann device, which all require the angles inside of the bridge and the pull to retract the tools. Even though the angles are not depicted in all of the patents, the tooling cannot be retracted through hardened metal, and thus must be there for the tooling to function.
U.S. Pat. No. 2,509,278 to Scheuermann discloses a mold that rotates the pull about its vertical axis to try and eliminate the angles on the inner surface of the pull loop. However, the angles are still required on the inner surface of the bridge, and the difficulty in producing the tools with the precision required for the pull rotation about the vertical axis has proven too costly.
U.S. Pat. No. 4,790,973 to Minami et al. discloses a different method and device for molding slider assemblies. Minami molds the slide first and, once the slide has solidified, a core is partially retracted to form the pull in a secondary molding operation while the slide is still positioned in the mold.
U.S. Pat. No. 5,013,511 to Akashi discloses yet another method and device for forming a zipper slide from metal. Akashi, like Minami, forms the slide portion in a first operation and forms the pull in a secondary operation. However, the pull of Akashi includes a pin which engages the bridge of the slide instead of the loop as disclosed in other prior art.
U.S. Pat. No. 4,985,969 to Terada et al. discloses yet another method and device for forming a zipper slide assembly. Terada forms the pull in combination with an intermediate pull portion with the two portions interlocked with a pin member that is formed within a mold as a secondary operation.
U.K. Patent Application No. 2,289,917 to YKK Corp. discloses a locking slider assembly. The YKK locking slider discloses forming the pull in a separate mold and placing the pull in a secondary mold where the slide is formed around a pin portion of the pull to complete the assembly.
Thus, a need in the art exists for a device and method of forming a slide in combination with a pull, wherein the slide and pull can be formed from metal without the need for modified geometry of the slide assembly, including internal angled surfaces in the bridge and the loop portion of the pull. A need also exists in the art for a slide and pull that operate to allow a larger degree of side to side movement between the slide and pull when operated in a first direction, and a more limited degree of side to side movement in a second direction to better accommodate ergonomics of the user and to better operate the slide fastener.
The combined slide and pull assembly should satisfy the ergonomic needs that a zipper slide assembly must satisfy in order to achieve acceptance by the end user. This includes providing a slide bridge that includes an internal surface geometry that allows free movement and rotation of the pull. Further, the zipper slide assembly should not require excessive strength to operate or include oversized component parts. Moreover, the zipper slide assembly must assemble together in such a way so as not to detract from the aesthetic appearance of the completed zipper assembly or garment assembly. The slide assembly should accommodate side to side movement of the puller during closure of the slide assembly, while restricting side to side movement during opening of the slide assembly for smoother operation and improved ergonomics of the slide assembly during operation thereof.
Thus, the present invention provides a die cast zipper slide assembly formed in a single operation which overcomes the disadvantages of prior art zipper slide assemblies formed in one or multiple operations. The zipper slide assembly of the present invention not only provides for relative ease in manufacturing, it also permits slides and pulls to be manufactured together without the need to put motion limiting and failure prone angles on the inner surfaces of the bridge and pull loop. The present invention also provides a manufacturing method which utilizes at least one side shifting slide, thereby eliminating the need for slides that interlock at angles and require the part geometry to be modified to accommodate the slide angles.

Metal one piece slide and pull for slide fastener


An integrated semiconductor memory includes a memory cell field having memory cells disposed in matrix form, word lines and internal bit lines forming pairs of internal bit lines for triggering the memory cells. Internal weighting circuits are each assigned to a respective one of the internal bit line pairs. An external pair of bit lines is commonly assigned to the internal bit lines. Pairs of separation transistors are each assigned to a respective one of the internal bit line pairs for electrical separation of the respective internal bit line pair from the external pair of bit lines. A bit line decoder triggers the pairs of separation transistors. An external weighting circuit is provided. A discriminator device and a precharging device are connected to the external bit line pair. The internal bit lines of each pair of internal bit lines are triggered separately from one another. The internal bit lines of each pair of internal bit lines are connected to the external bit line pair separately from one another.

Field of the Invention .Iaddend.
The invention relates to an integrated semiconductor memory, having memory cells disposed in matrix form in a memory cell field, which are triggerable through word lines and internal bit lines forming pairs of internal bit lines, one internal weighting circuit per internal bit line pair, one pair of separation transistors per internal bit line pair for the electrical separation of the internal bit line pair from an external pair of bit lines that are common to the internal bit Lines, a bit line decoder for triggering the pairs of separation transistors, an external weighting circuit, and a discriminator device and a precharging device which are connected to the external bit line pair.
Modern integrated semiconductor memories contain a great number of memory cells. For instance, modern DRAMs have a memory capacity of 4 or 16 megabits. The testing time for typical function tests is known to increase linearly at least twice as fast as the number of memory cells increases. Many test patterns in fact produce a quadratic increase in testing time as memory capacity increases. Attempts have therefore already been made for some time to provide devices in the semiconductor memory itself that make it possible to shorten the testing time. For instance, that can be attained by operating a plurality of memory cells (which operate independently of one another in normal operation) parallel to one another in the test mode, ascertaining the outcome of testing internally in the memory, and finally making the results available as an error signal at the usual data output terminal.
A circuit configuration of that generic type is known, for instance, from Published European Application 0 283 907 A1 corresponding to U.S. Pat. No. 4,956,819. That device enables a simultaneous readout of (test) data from all of the memory cells disposed along one word line. Such a memory can accordingly be tested parallel, line by line. There are two disadvantageous aspects of the known circuit configuration: First, for the test mode, a potential that is quantitatively between the two typical supply potentials of the semiconductor memory must be furnished to trigger the separation transistors. That requires an independent generation of potential on the semiconductor chip itself. Second, in the test mode, it may happen that if an error occurs in one memory cell in a single word line, the internal weighting circuit assigned to the memory cell, after an initially correct weighting, will incorrectly flip into a state that indicates that the (actually defective) memory cell is functioning properly. One way in which that may happen, if the potential at the gate of the separation transistors is dimensioned disadvantageously, is that the (correct) data, which are read out from the other memory cells on the same word line and naturally reach the external bit line in the form of electrical potential over their internal bit lines and thus also reach the bit line connected to the defective memory cell, may pull or push this bit line to a potential that causes the internal weighting circuit to flip. Thus the internal weighting circuit flips from the state that originally correctly indicated the defective memory cell to a state that is meant to indicate a "good" cell.
It is accordingly an object of the invention to provide an integrated semi-conductor memory, which overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices of this general type and which des so in such a way that the aforementioned error cannot occur.
With the foregoing and other objects in view there is provided, in accordance with the invention, an integrated semiconductor memory, comprising a memory cell field having memory cells disposed in matrix form, word lines and internal bit lines forming pairs of internal bit lines for triggering the memory cells, internal weighting circuits each being assigned to a respective one of the internal bit line pairs, an external pair of bit lines being commonly assigned to the internal bit lines, pairs of separation transistors each being assigned to a respective one of the internal bit line pairs for electrical separation of the respective internal bit line pair from the external pair of bit lines, a bit line decoder for triggering the pairs of separation transistors, an external weighting circuit, a discriminator device and a precharging device connected to the external bit line pair, means for triggering the internal bit lines of each pair of internal bit lines separately from one another, and means for connecting the internal bit lines of each pair of internal bit lines to the external bit line pair separately from one another.
In accordance with another feature of the invention, the separate triggering means are part of the bit line decoder and operate as a function of a pair of test signals.
In accordance with a further feature of the invention, the bit line decoder has a decoder line, and the separate triggering means include a pair of series-connected switch transistors having sources connected in common to the decoder line, drains connected to gates of the separation transistors, and gates connected to the pair of test signals, for separate triggering of the pairs of separation transistors.
In accordance with an added feature of the invention, the separation transistors are first separation transistors, the separate triggering means trigger the transistors of each pair of first separation transistors in parallel with one another, and there are provided pairs of second separation transistors each being assigned to a respective one of the pairs of first separation transistors for separate triggering of the internal bit lines of each pair of internal bit lines, each of the first separation transistors being connected in series with a respective one of the second separation transistors, and in each pair of second separation transistors, one transistor being controlled by a first test signal and the other transistor being controlled by a second test signal.
In accordance with an additional feature of the invention, the pairs of second separation transistors are disposed between the memory cell field and the pairs of first separation transistors.
In accordance with yet another feature of the invention, the pairs of second separation transistors are disposed between the external bit line pair and the pairs of first separation transistors.
In accordance with yet a further feature of the invention, there is provided a common diffusion zone acting as respective source and drain zones for a transistor of a pair of second separation transistors and one transistor of a pair of first separation transistors connected thereto.
In accordance with yet an added feature of the invention, there are provided conductor tracks of the external bit line pair, and conductor tracks carrying the test signals and shielding with respect to the conductor tracks of the external bit line pair.
In accordance with a concomitant feature of the invention, in a test mode, one of the bit lines of the external bit line pair is precharged to logical 1, and the other of the bit lines of the external bit line pair is precharged to a potential being lower than the value of logical 1 by half an amount by which the one bit line of the external bit line path precharged to logical 1 drops in the case of error.
Other features which are considered as characteristic for the insertion are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in an integrated semiconductor memory, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scone and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.


An agent may be coupled to receive a clock signal associated with the bus, and may be configured to drive a signal responsive to a first edge (rising or falling) of the clock signal and to sample signals responsive to the second edge. The sampled signals may be evaluated to allow for the driving of a signal on the next occurring first edge of the clock signal. By using the first edge to drive signals and the second edge to sample signals, the amount of time dedicated for signal propagation may be one half clock cycle. Bandwidth and/or latency may be positively influenced. In some embodiments, protocols which may require multiple clock cycles on other buses may be completed in fewer clock cycles. For example, certain protocols which may require two clock cycles may be completed in one clock cycle. In one specific implementation, for example, arbitration may be completed in one clock cycle. Request signals may be driven responsive to the first edge of the clock signal and sampled responsive to the second edge. The sampled signals may be evaluated to determine an arbitration winner, which may drive the bus responsive to the next occurrence of the first edge.

1. Field of the Invention
This invention is related to digital systems and, more particularly, to buses within digital systems.
2. Description of the Related Art
A bus is frequently used in digital systems to interconnect a variety of devices included in the digital system. Generally, one or more devices are connected to the bus, and use the bus to communicate with other devices connected to the bus. As used herein, the term "agent" refers to a device which is capable of communicating on the bus. The agent may be a requesting agent if the agent is capable of initiating transactions on the bus and may be a responding agent if the agent is capable of responding to a transaction initiated by a requesting agent. A given agent may be capable of being both a requesting agent and a responding agent. Additionally, a "transaction" is a communication on the bus. The transaction may include an address transfer and optionally a data transfer. Transactions may be read transactions (transfers of data from the responding agent to the requesting agent) and write transactions (transfers of data from the requesting agent to the responding agent). Transactions may further include various coherency commands which may or may not involve a transfer of data.
The bus is a shared resource among the agents, and thus may affect the performance of the agents to the extent that the bus may limit the amount of communication by each agent and the latency of that communication. Generally, a bus may be characterized by latency and bandwidth. The latency may be affected by the amount of time used to arbitrate for the bus and to perform a transaction on the bus. The bandwidth may be affected by the amount of information (e.g. bits or bytes) that may be transmitted per cycle, as well as the amount of time used to perform the transfer. Both latency and bandwidth may be affected by the physical constraints of the bus and the protocol employed by the bus.
For example, many bus protocols require two clock cycles for arbitration: the transmission of the requests for the bus during the first clock cycle and the determination of the grant (and transmittal of the grant, in a central arbitration scheme) during the second clock cycle. The transaction may be initiated by the agent receiving the grant during the third clock cycle. The clock cycles may each be a period of a clock signal associated with the bus. Similarly, most bus protocols are limited in the number of bytes of data which may be transferred per clock cycle (e.g. 8 bytes is typical). Accordingly, transferring a cache block of data (which tends to dominate the transfers performed in modem digital systems) requires multiple clock cycles (e.g. 4 clock cycles for a 32 byte cache block on an 8 byte bus).

Bus sampling on one edge of a clock signal and driving on another edge


A marine vessel running controlling apparatus includes a steering angle acquiring unit which acquires the steering angle of a steering mechanism provided in a marine vessel, and a control unit which controls a lift force difference generating unit for generating a lift force difference between a port side and a starboard side of the marine vessel according to the steering angle acquired by the steering angle acquiring unit. The control unit may control the lift force difference generating unit to increase the heel angle of the marine vessel in a direction defined by the steering angle, if the steering angle falls outside a neutral range.

1. Field of the Invention
The present invention relates to a marine vessel including a lift force difference generating unit which generates a lift force difference between a port side and a starboard side of the marine vessel, and a marine vessel running controlling apparatus for a marine vessel.
2. Description of the Related Art
An inertial navigation system provided in a marine vessel is generally capable of detecting the yaw angular speed, the roll angle, and the pitch angle of the marine vessel. In an ordinary marine vessel running state, the roll angle of the marine vessel is zero during straight traveling of the marine vessel, and is non-zero during turning of the marine vessel. On the other hand, the marine vessel steadily has a non-zero roll angle over a long period of time when traveling with its gravity center shifted to a starboard side or a port side due to unevenly loaded cargo or due to wind blowing on its broadside. Such a steady-state roll angle, i.e., an average of roll angles measured over a long period of time, is herein referred to as "heel angle", which is intended to be differentiated from the roll angle. The attitude of the marine vessel observed when the heel angle is zero with respect to a water surface or a transverse axis of the marine vessel is parallel to the water surface is herein referred to as "neutral attitude".
When a marine vessel 80 travels in a non-neutral attitude at a non-zero heel angle as shown in FIG. 11A, a lift force difference occurs between a starboard side and a port side of a hull 81 of the marine vessel 80, making it difficult for the marine vessel to travel straight. At this time, as shown in FIG. 11B, an operator of the marine vessel operates a steering wheel 82 to balance the lift forces on the starboard side and the port side, thereby causing the marine vessel to travel straight. In this state, however, the traveling direction of the marine vessel 80 does not coincide with the bow direction of the marine vessel 80, so that the hull 81 is subjected to a great resistance. This reduces the propulsive efficiency of a propulsion system 83.
Automatic attitude controlling apparatuses for controlling the marine vessel in the neutral attitude are disclosed, for example, in U.S. Pat. No. 5,474,012 and Japanese Unexamined Patent Publications No. HEI9(1997)-76992, No. HEI9(1997)-315384, and No. 2004-224103. With the use of any of these apparatuses, the trim angles of outboard motors or the angles of flaps are controlled according to an output of a roll angle sensor to keep the heel angle at zero.
If the operator performs a steering operation to nullify the heel angle, however, the automatic attitude controlling apparatus is no longer operative. Therefore, the marine vessel continuously travels with its propulsion system driven at a reduced propulsive efficiency.

Marine vessel running controlling apparatus, and marine vessel employing the same


A plurality of pits representing recording target information are formed on an optical disk, while a laser light having a predetermined power is irradiated onto the optical disk. When information is being recorded, a condition index representing a recording condition of the optical disk is derived with the use of an equation which is changeable in accordance with the kind of the optical disk and the operational environment of a recording apparatus. The power of the laser light irradiated onto the optical disk is adjusted so that the recording condition may be a predetermined recording condition based on the derived condition index.

1. Field of the Invention
The present invention relates to an information recording method, a recording condition detection method, and an information recording apparatus.
2. Description of the Related Art
A recording condition of an optical disk is represented by two parameters, namely, "asymmetry" and "β".
Each of "asymmetry" and "β" represents an asymmetric characteristic of the waveform of a reproduction signal (RF (Radio Frequency) waveform) which is obtained when information recorded on an optical disk is reproduced.
"Asymmetry" is derived from a reproduction signal obtained by DC (direct-current) coupling, whereas "β" is derived from a reproduction signal obtained by AC (alternating-current) coupling.
A recording apparatus for recording information on an optical disk changes the power of a laser light irradiated on the optical disk in accordance with a digital signal obtained by EFM (Eight to Fourteen Modulation). Due to this, a plurality of pits representing information to be recorded are formed on the optical disk.
The time width (pulse width) of the high level and the low level of the aforementioned digital signal is generally regulated to three times to eleven times as large as a predetermined reference time width T.
Since the recording apparatus changes the power of a laser light in accordance with pulse widths 3T to 11T, the lengths of pits to be formed also vary in accordance with the pulse widths 3T to 11T.
FIGS. 1A and 1B respectively show waveforms of reproduction signals obtained from pits having lengths corresponding to the aforementioned pulse widths 3T to 11T. Specifically, FIG. 1A is a diagram showing waveforms of reproduction signals (HF (High Frequency) signals) obtained by DC coupling, and FIG. 1B is a diagram showing waveforms of reproduction signals (HF signals) obtained by AC coupling.
As shown in FIGS. 1A and 1B, the frequencies and amplitudes of the reproduction signals vary in accordance with the lengths of the pits. For example, the amplitude of a reproduction signal obtained from a pit having the length of 3T (the shortest pit) is the smallest, while the amplitude of a reproduction signal obtained from a pit having the length of 11T (the longest pit) is the largest.
Let it be assumed in FIG. 1A that the local maximum level of the reproduction signal of 3T is I3L and the local minimum level thereof is I3P, and the local maximum level of the reproduction signal of 11T is I11L and the local minimum level thereof is I11P. In this case, the "asymmetry" is represented by the equation (1) below.Asymmetry={(I3L+I3P)/2−(I11L+I11P)/2}/(I11L−I11P)  (1)
Further, let it be assumed in FIG. 1B that AC-GND is zero level, the maximum level (land level) of the waveform envelopes is A1, and the minimum level (pit level) of the waveform envelopes is A2. In this case, "β" is represented by the equation (2) below.β=(A1+A2)/(A1−A2)  (2)
There is a relationship shown in FIG. 2 between the parameter β (asymmetry) and jitter, for example.
As shown in FIG. 2, when the value of β is extremely large or extremely small, the jitter value becomes large.
The value range of β in which jitter values are equal to or smaller than a tolerable level is generally called "power margin". The power margin varies in accordance with the kinds of optical disks.
In a case where information is to be recorded on an optical disk having a narrow power margin, the information must be recorded such that the values of β become uniform.
When recording information, experimental writing is first performed in a PCA (Power Calibration Area) prepared on the optical disk, in order to perform so-called OPC (Optimum Power Calibration). As a result, the power of a laser light that realizes the optimum recording condition (optimum power) is derived.
Afterwards, the information to be recorded is recorded on the data recording area prepared on the optical disk, by the optimum power derived by the OPC.
However, although the information is recorded by the optimum power derived by the OPC, there are some cases where the recording condition can not be kept optimum, due to various causes described below.
Such causes are, for example:
(a) changes in the property inside the optical disk;
(b) changes in the angle between the optical axis of the laser light and the recording surface of the optical disk, caused by radial skews, warping of the disk, etc.;
(c) changes in the property of the optical disk, due to changes in the temperature between the time of performing the OPC and the time of recording information; and
(d) changes in the wavelength of the laser light, due to changes in the characteristic of a semiconductor element which emits the laser light, caused by changes in the temperature between the time of performing the OPC and the time of recording information.
As one method for solving the above described problems, there is a method called "running OPC". The running OPC is for keeping the optimum recording condition, by detecting the recording condition even while information is recorded and by correcting the power of the laser light irradiated on the optical disk based on the detected recording condition.
Such a method for detecting the recording condition during information recording is disclosed in, for example, Unexamined Japanese Patent Application KOKAI Publication No. 2000-215454 (Publication 1), Unexamined Japanese Patent Application KOKAI Publication No. H9-270128 (Publication 2), and Unexamined Japanese Patent Application KOKAI Publication No. H9-91705 (Publication 3).
The technique disclosed in Publication 1 derives the recording condition during information recording, using the equation (3) below.Recording condition=(B value)/(PEAK value)  (3)                B value: the minimum intensity of a reflection light from an area where a pit is to be formed during information recording        PEAK value: the maximum intensity of a reflection light from the area where a pit is to be formed during information recording
The technique disclosed in Publication 2 derives the recording condition during information recording, using the equation (4) below.Recording condition=Am/N−Bm  (4)                Am: the average of the maximum intensities of reflection lights from the areas where pits are to be formed        N: a constant corresponding to the kind of the optical disk        Bm: the average of the intensities of reflection lights which are observed when the reference time width T passes from the points from which the respective pits are to be formed
The technique disclosed in Publication 3 derives the recording condition during information recording, using the equation (5) below.Recording condition=Vp/P1  (5)                Vp: the level of a reflection light from the area where a pit is to be formed during information recording        P1: the power of the laser light for forming pits
However, the techniques disclosed in Publications 1, 2, and 3 are not able to keep the optimum recording condition derived by the OPC throughout the information recording in some cases.
Specifically, when the kinds of the optical disks are changed or operational environments of the recording apparatus are changed, the recording condition may not be represented correctly by the equations (3), (4), and (5). Therefore, the recording condition might be changed even when the running OPC is performed by using the equations (3), (4), and (5).
The techniques disclosed in Publications 1, 2, and 3 do not at all take into consideration the fact that the most appropriate calculation required to derive the recording condition is different depending on the kinds of the optical disks and the operational environments of the recording apparatus. Therefore, there are some cases where the techniques disclosed in Publications 1, 2, and 3 can not keep the optimum recording condition derived by the OPC throughout the information recording.
The contents of Publications 1, 2, and 3 described above are incorporated herein by reference.

Information recording method, recording condition detection method, and information recording apparatus


A method and apparatus for representing and storing the schedules of recurring events. The schedules are represented by recurrence rules generated according to a specific grammar. According to the grammar, each recurrence rule is composed of one or more recurrence commands. Each recurrence command corresponds to a cycle and includes a time interval indicator that specifies the duration of the cycle and a repeat quantity that determines the number of times the cycle is repeated in the schedule. Each recurrence command may also include an occurrence list that specifies at what times during a particular cycle the event occurs. The occurrence list may specify times in absolute or relative terms. Thus, the grammar supports recurrence rules for representing the schedule "first and tenth of every month" as well as the schedule "second Thursday and last Friday of every month". To represent schedules that terminate before the last event in the last cycle is completed, a symbol may be inserted into the occurrence list to distinguish the events that are performed on the last cycle from the events that are not performed on the last cycle. Complex schedules that involve cycles repeated within cycles are represented by multiple-command recurrence rules. The stored recurrence rules may be parsed to determine when events will occur. The grammar may be applied to a variety of applications, including calendar programs, video cassette recorders and home automation devices.

Numerous software programs have been developed that allow users to store schedules of events into a computer. Typically, such programs also generate visual displays that illustrate the events that will occur during a specified time period (e.g. calendars). Using such programs, users may, for example, enter information about events that are scheduled to occur during a particular month. The software stores the information on a storage device. At any time thereafter, users may instruct the software to generate a calendar of the month. When generating the calendar, the software generates indications of the scheduled events on the appropriate days of the calendar.
Calendar applications that use a client/server model have been developed. With such applications, a user interacts with a client application to enter information about events, including when the events will occur. The client application transmits data representing the events to a server application. The server application stores data representing the events. Subsequently, the client application may transmit data representing a time period, such as a particular month or year, to the server application. The server application reads the stored event data, determines which events are scheduled to occur during the specified time period, and transmits data representing the appointments that are scheduled to occur during the specified time period back to the client application. The client application then generates a calendar of the specified time period along with visual indications of the events that will occur during the specified time period.
Some events occur on a regular basis. Rather than require a user to enter information for each occurrence of a recurring event, most calendar applications allow the user to specify a first occurrence of the event and a recurrence interval for the event. For example, a user may have to attend a certain meeting every Friday at 10:00 am. Rather than enter information for each occurrence of the meeting, the user can enter information about the first occurrence of the meeting and an indication that the meeting takes place on a weekly basis (the "recurrence interval").
When generating a calendar for a particular time period, calendar applications that support recurring events must calculate if and when the event will occur during the particular time period. The calendar application makes this determination based on the initial occurrence time and the recurrence interval. Typically, a calendar application makes this determination when a user requests a calendar display of a particular period.
Current calendar applications support many typical recurrence intervals. For example, some current calendar applications allow a user to specify that an event recurs daily, weekly, monthly, or Monday through Friday. However, events that recur at less typical intervals may require multiple entries. For example, to specify an event that occurs every Monday and Wednesday, a user may have to schedule the event as if it were two weekly events. That is, the user may have to input a first event entry to indicate that the event occurs weekly every Monday, and then a second event entry to indicate that the event occurs weekly every Wednesday. Events that recur at less regular patterns may be even more difficult to specify. Consider, for example, an event that occurs on the second Tuesday and the fourth Friday of every month.
Events that recur at smaller intervals within larger intervals may be impossible to specify using current calendar applications. For example, consider an event that occurs every Monday (weekly) of every third month (monthly). Similarly, consider an event that occurs every hour (hourly) of every Wednesday (weekly).
It is clearly desirable to provide a mechanism to represent complex schedules with single event entries. It is further desirable that the schedules be represented and stored in a concise fornat to minimize the storage space required for event schedule information.

Method and apparatus for representing recurring events

International Business Machines Corporation


A wire feed device for a wire cut electric spark machine in which a wire is delivered from a wire bobbin in the direction orthogonal to the axis of the wire bobbin to prevent a "jump" of the wire as well as a fluctuation in wire tension arising from the jump, and which can reduce a space required for the arrangement thereof, includes a roller intervening between a wire bobbin with a wire accumulatively wound therearound, and a guide roller. The intervening roller is adapted to reverse the delivery direction of the wire sent from the wire bobbin toward the guide roller, and presents an outer peripheral surface having surface capable of not only confining at all times a wire delivery angle within a predetermined angle regardless of a wire delivery position, but also maintaining the same length of the wire extending from the wire delivery position, via the intervening roller, up to the guide roller.

For the purpose of machining a workpiece, a wire cut electric discharge machine intermittently generates a spark or discharge between the workpiece and a wire electrode (hereinbelow, referred to simply as a wire) running along a wire running passage, while displacing the wire with respect to the workpiece. A wire feed device to be mounted on the electric discharge machine and for running the wire, typically comprises a wire bobbin, a guide roller for guiding the wire, a tension roller operative to apply a tension to the wire, and a feed roller for the drive of the wire, in which the wire is tensioned-along the wire running passage extending through the above-described rollers, and then the feed roller is rotationally driven to deliver the subsequent wire from the wire bobbin.
During the delivery of the wire, a wire delivery position lying on the wire bobbin is displaced in the width direction of the bobbin, and the direction in which the wire delivery position is displaced is reversed when the outermost wire layer is replaced by the subsequent wire layer. With the displacement of the wire delivery position, there varies an angle (hereinafter, referred to as a wire delivery angle) defined by an imaginary line extending through the wire delivery position and orthogonally to the axis of the wire bobbin, and a line obtained by projecting the wire let out from the wire bobbin onto an imaginary plane extending through the wire delivery position.
In case the wire is delivered diagonally from the wire bobbin toward the guide roller with a larger wire delivery angle, the delivered wire possibly runs onto the adjacent wire constituting a wire layer to which that wire is to belong. On the contrary, with the displacement of the wire delivery position, the wire which ran onto the adjacent wire possibly returns to the ordinary winding position. Such running onto the adjacent wire and or return to its ordinary position of the wire (hereinafter, referred to as a "jump" of the wire), may lead to a fluctuation in the wire tension, to degrade the machining accuracy, in particular, the surface roughness, which brings about a deterioration in quality of machined product.
Incidentally, it is possible to reduce the wire delivery angle which would otherwise cause a "jump", by enlarging the interval between the wire bobbin and the guide roller. The provision of a greater interval between the wire bobbin and the guide roller enough to prevent the occurrence of "jump" leads to an excessive enlargement in size of the electric discharge machine, which is impractical.


A device and method for determining the position for a working part of a machine with a position-determining apparatus is disclosed. A detector is placed at a defined place on the machine to determine the position in a fixed coordinate system. A positional relationship device determines the positional relationship of the working part in relation to the detector in a machine-based coordinate system. A calculating device calculates, with signals from the position-determining apparatus and the positional relationship device, the position of the working part in the fixed coordinate system. The position-determining apparatus comprises an inclination- and orientation-measuring device that measures the instantaneous position and orientation of the position of the machine in the fixed coordinate system. The calculating device converts the measuring result from the position-determining apparatus and the positional relationship device to give the instantaneous position and orientation of the working part in the fixed coordinate system.

The present invention relates generally to determining the position of a working part of a tool on a machine and, in particular, relates to the controlling the position of a working part of a tool of an industrial machine, such as, for example a ground-leveling machine, crane, dredger or the like.
During road construction or the leveling of ground, for example for buildings, parks or playgrounds, vehicle displays or the like, ground preparation machines are used which are to give a predetermined topography to the piece of ground through, on one hand digging and on the other hand piling up material.
It is important in this connection that the working tools on the machines which are used can be accurately controlled to the exact right working level in the intended section. The control should preferably even be able to be remote-controlled automatically so that the desired topography in the right position inside a section should be able to be written into a computer program and information concerning suitable processing should be able to be given continuously and automatically to the driver of the vehicle. It should also, in the cases where it is possible, be able to have automatic controlling of the machines in order to perform certain work completely automatically.
This implies that for ground-working equipment one needs to keep track of the exact position in space of the working tools' positions in space, the angular position in both horizontal and vertical directions and their working directions.

Device and method for determining the position of a working part