A servo method for an optical recording medium for detecting a tracking error signal by a push-pull method is disclosed. Before a servo operation, an amount of DC offset per track is obtained as an object lens of an optical pickup is moved in a specified direction, and a tracking servo is performed by compensating for a tracking error signal based on an initial amount of DC offset obtained by multiplying the amount of DC offset generated per track by the number of jumped tracks when the object lens is shifted. After movement of a sled by driving a sled servo, a sled servo is performed by compensating for the tracking error signal based on a value obtained by subtracting an amount of sled movement from the initial amount of DC offset, and thus an optical beam can always follow a track center even when the DC offset is generated in the tracking error signal.

1. Field of the Invention
The present invention relates to a system for an optical recording medium, and more particularly, to a servo method for a push-pull type optical recording medium.
2. Background of the Related Art
With the growth of audio and video media, an optical recording/reproducing apparatus for recording and reproducing video and audio data in a semi-permanent optical recording medium has been developed.
An optical recording medium, and especially an optical disc used for data recording and reproduction in the optical recording/reproducing apparatus is classified into three types according to its function and purpose: a read only memory (ROM) type, write one read many (WORM) type on which data can be written only once, and rewritable type on which data can be repeatedly written.
Here, as the ROM type optical disc, there exist a compact disc read only memory (CD-ROM), digital versatile disc read only memory (DVD-ROM), etc., and as the WORM type optical recording medium, there exist a recordable compact disc (CD-R) on which data can be written only once, recordable digital versatile disc (DVD-R) on which data can be written only once, etc.
Meanwhile, as the rewritable optical disc, there exist a rewritable compact disc (CD-RW), rewritable digital versatile disc (DVD-RW, DVD-RAM, and DVD+RW), etc.
Various methods of controlling a tracking such as a three-beam method, push-pull (PP) method, differential phase detection (DPD) method, etc., have been used in the optical discs of a CD or DVD series.
Here, according to the three-beam method, a pair of side beam spots for the tracking are arranged in front and rear of a main beam spot for decoding information, respectively. That is, the side beams are arranged opposite to each other from a track center by ¼ of a track width. This arrangement of the side beams is for preventing an omission of detected signals and for avoiding a cross talk from an adjacent track.
At this time, an optical detector includes a center optical detection element for detecting a light quantity of the main beam, and side optical detection elements for detecting a light quantity of the side beam. For example, as shown in FIG. 1, the center optical detection element is composed of four optical detection elements PDA, PDB, PDC, and PDD divided in a signal track direction and in a radial direction of the optical disc, respectively. Two side optical detection elements PDE and PDF are positioned on upper and lower ends of the center optical detection element, respectively. Here, a tracking error signal is obtained by calculating "e−f" with respect to electric signals e and f outputted from the side optical detection elements PDE and PDF.
Also, according to the push-pull (PP) method, the optical detection elements of the optical detector are divided into two parts in the track direction, and a tracking error signal is detected from a light quantity balance of the two-part optical detection elements. Specifically, this method uses the fact that the intensity distribution of light, that is diffracted and reflected by a pit and then incident again to an object lens, varies according to the relative variation of positions of the pit and spot.
At this time, if the shadow of the pit is equally detected by the both optical detection elements, the tracking error (TE) signal becomes "0", and this state is called a tracking-on (or on-track) state. On the contrary, if the optical beam deviates left and right from the track center, the tracking error (TE) signal has a positive (+) or negative (−) value, and this state is called a tracking-off (or off-track) state.
In case that the optical detector is divided into 4 optical detection elements PDA, PDB, PDC, and PDD in the signal track direction and radial direction of the optical disc, the tracking error signal according to the PP method can be obtained by calculating "(a+d)−(b+c)" with respect to the electric signals a, b, c, and d outputted from the optical detection elements of the optical detector. At this time, in case that the optical detector is divided into two parts in the track direction, the tracking error signal (=I1−I2) is detected from the light quantity balance of two photodiodes I1 and I2. That is, "a+d" of FIG. 1 corresponds to I1, and "b+d" corresponds to I2.
If it is assumed that the optical detector is the same as in FIG. 1, the main beam push-pull (BPP) signal can be obtained by calculating "(a+d)−(b+c)" with respect to the electric signals a, b, c, and d outputted from the center optical detection element of the optical detector, and the side beam push-pull (SPP) signal can be obtained by calculating "e−f" with respect to the electric signals e and f. Also, the differential push-pull (DPP) signal can be obtained by calculating "MPP-SPP". Here, in case that the optical detector is composed of 4 divided optical detection elements PDA, PDB, PDC, and PDD in the signal track direction and radial direction of the optical disc, or 2 divided optical detection elements I1 and I2 in the track direction, the PP signal and MPP signal have the same concept.
At this time, the MPP method has several conditions. According to one among them, if the wavelength of the light is λ and the depth of the pit is λ/4, i.e., if the diffraction by the pit is most effective and the depth of modulation becomes maximum, the tracking error signal cannot be obtained through the MPP method. In other words, since the pattern becomes symmetric when the depth of the pit is λ/4, the tracking error signal cannot be obtained through the 2-divided optical detector.
Meanwhile, the DPD method is an improvement of the MPP method. In the same manner as the MPP method, the DPD method uses the intensity distribution of light according to the relative positional change of the beam and pit, but it uses the 4-divided optical detector instead of the 2-divided optical detector.
Specifically, according to the DPD method, the intensity distribution of the light is received through the 4-divided optical detection elements, and the tracking error signal is generated through the detection of the phase difference in the radial direction.
Accordingly, the tracking error signal is outputted even if the depth of the pit is λ/4, and is not much affected by movement of the beam on the optical detector as well.
In case that the optical detector is divided into 4 optical detection elements PDA, PDB, PDC, and PDD in the signal track direction and radial direction of the optical direction, the DPD method obtains the tracking error signal through the detection of the phase difference between the electric signals of "a+c" and "b+d" based on the RF signal of "a+b+c+d" obtained from the electric signals a, b, c, and d outputted from the respective optical detection elements.
For example, the existing CD generates the tracking error signal using the three-beam method, and the CD recorder generates the tracking error signal using the differential push-pull (DPP) method. At this time, in case that the signal outputted from the center optical detection element is received and the tracking error signal is detected using the MPP method, the quantity of the MPP signal becomes great, and a DC offset is produced through a lens shift.
Accordingly, the CD recorder generates the tracking error signal in a manner that the DC offset is minimized using the DPP (DPP=MPP−SPP) method, i.e., using the signal obtained in the main push-pull (MPP) method and side push-pull (SPP) method, to solve the DC offset problem in the MPP method.
Also, the DVD-ROM generates the tracking error signal using the DPD method. Specifically, since the depth of the pit is λ/4 in case of the DVD-ROM, the tracking error signal cannot be detected through the MPP method. Thus, the DVD-ROM obtains the tracking error signal using the DPD method. Also, the DVD-R/RW detects the tracking error signal using the DPD method in case of reproducing a region where the signal is recorded, while it detects the tracking error signal using the MPP method in case of recording the signal. Also, the DVD-RAM detects the tracking error signal using the DPD method only with respect to a pre-pit region, while it detects the tracking error signal using the MPP method with respect to other regions.
Meanwhile, after the tracking error signal is detected using one among the above-described methods, a tracking servo should be performed using the detected tracking error signal. At this time, as the tracking servo driving method, there exist a method of driving the object lens only, and a method of driving the whole optical pickup. Here, in order to move the whole optical pickup, a sled motor should be driven by a sled servo.
Also, in case of a seek or search operation for searching a desired position on the optical disc, there exist a method of driving the object lens only, and a method of driving the whole optical pickup. Specifically, in case of a rough seek for Specifically, in case of a rough seek for jumping over several hundred tracks to several thousand tracks to reach a target track, the whole optical pickup is moved near the desired track through the drive of the sled motor, and then in case of a fine seek for jumping over several hundred tracks or less, the target track is sought only using the object lens of a tracking actuator.
Meanwhile, in case that the tracking error signal is detected by the MPP method as the object lens of the tracking actuator is moved left and right through the lens shifting method during the tracking servo, the spot is moved on the optical detector, and the DC offset is produced in the tracking error signal. That is, the DC offset is produced in the tracking error signal through the lens shift although the optical beam is positioned on the center track, and this causes the center of the reflected light not to coincide with the center of the optical detector. Here, The DC offset means that the position of the spot leans to the upper or lower part of the optical detector. In this case, since the optical beam is on the track center, the DC offset state should be maintained as it is.
As shown in FIG. 2A, if it is assumed that B indicates the normal focusing state that no lens shift is performed and A and C indicate the shifted positions of the object lens, FIGS. 2B to 2D show examples of the reflected light detected by the optical detector. That is, if it is assumed that the optical beam is positioned on the track center, the center of the reflected light coincides with the center of the optical detector as shown in FIG. 2C in case that the lens shift does not exist, and the center of the reflected light does not coincide with the center of the optical detector due to the DC offset as shown in FIGS. 2B and 2D in case that the lens shift is performed. Here, FIG. 2B shows an example that the DC offset is produced toward I2, and FIG. 2D shows an example that the DC offset is produced toward I1.
Then, a servo control section in the conventional optical recording/reproducing apparatus as shown in FIG. 3 judges that the optical beam deviates from the track center, and produces a control signal for controlling the center of the reflected light and the center of the optical detector to coincide with each other. Accordingly, the optical beam may deviate from the track center.
FIG. 3 is a block diagram illustrating the construction of the general optical disc recording/reproducing apparatus. Referring to FIG. 3, an optical pickup 102, under the control of a servo control section 104, puts the optical beam condensed by the object lens on the signal track of the optical disc 101. The light reflected from a signal recording surface is condensed again by the object lens, and then incident to the optical detector for detecting a focus error signal and tracking error signal.
For example, the optical detector is composed of a plurality of optical detection elements as shown in FIG. 1, and electric signals in proportion to the light quantities obtained by the respective optical detection elements are outputted to an RF and servo error generating section 103.
The RF and servo error generating section 103 detects an RF signal for data reproduction, and the focus error (FE) signal, tracking error (TE) signal, etc., for servo control from the electric signals outputted from the respective optical detection elements of the optical detector.
The detected RF signal is outputted to a data decoder (not illustrated) for reproduction, and the servo error signals such as the FE signal, TE signal, etc., are outputted to the servo control section 104.
The servo control section 104 outputs a drive signal for controlling the focus to a focus servo driving section 105 by processing the focus error (FE) signal, and outputs a drive signal for controlling the tracking to a tracking servo driving section 106 by processing the tracking error (TE) signal.
Then, the focus servo driving section 105 moves the optical pickup 102 up and down by driving the focus actuator in the optical pickup 102, so that the optical pickup 102 follows the up/down movement of the rotating optical disc 101.
The tracking servo driving section 106 moves the object lens of the optical pickup 102 in the radial direction by driving the tracking actuator in the optical pickup 102, and thus corrects the position of the beam to follow a specified track.
Also, in case of moving the whole optical pickup, a sled servo driving section 107 receives a sled control signal and forward (or reverse) signal from the servo control section 104, and drives a sled motor 108 to directly move the optical pickup body in a desired direction. Specifically, the servo control section 104 generates the sled control signal using the tracking error signal, and outputs the sled control signal to the sled servo driving section 107. That is, the tracking error signal becomes symmetric, i.e., positive (+) or negative (−), when the optical pickup 102 is not positioned on the center of the track. Meanwhile, the sled servo driving section 107 drives the sled motor 108 so that the rotation of the sled motor 108 corresponds to the quantity of output of the optical pickup 102, and this means that the control voltage of the sled motor 108 changes the rotating number of the sled motor to change the speed of the sled motor. For example, the forward signal inputted to the sled servo driving section 107 is the positive or negative voltage applied to the sled motor 108, and makes the sled motor 108 rotate to move the optical pickup 102 in the desired direction.
For example, as shown in FIG. 4, if it is assumed that a control reference voltage (i.e., center voltage TEref) is determined and the tracking error (TE) signal is inputted from the RF and servo error generating section 103, the servo control section 104 generates the tracking control signal so that the difference between the tracking error (TE) signal and reference voltage Teref (Δε=TE−TEref) becomes "0" if Δε is not "0". Then, the tracking servo driving section 106 generates a tracking drive (TD) signal in proportion to the tracking control signal outputted from the servo control section 104, and drives the tracking actuator in the optical pickup 102. If the tracking actuator is driven, the tracking drive voltage increases to move the object lens of the optical pickup 102 in the radial direction.
At this time, the servo control section 104 considers that the optical beam follows the track center when Δε becomes "0".
However, since the DC offset exists in the tracking error (TE) signal that has already inputted through the lens shift, the tracking drive (TD) signal outputted from the tracking servo driving section 106 has the DC offset as much as α. Accordingly, the tracking servo driving section 106 is overdriven as much as α.
As a result, the optical beam deviates from the track center. In this case, the tracking actuator cannot follow the track center often. Especially, if the DC offset becomes great, the tracking servo cannot follow the corresponding track, and thus the tracking servo becomes off. This causes the recording/reproduction of data to be difficult.
In particular, since the DVD recorder controls the tracking only using the MPP method during the recording operation, it is greatly affected by the DC offset generated by the lens mechanism. That is, as high-density DVDs are provided, the DC offset exerts a great effect on the cross talk or cross eraser (i.e., erasing data recorded on the neighboring track by affecting the neighboring track during the recording operation) Also, in the DVD-R/RW having a small PP signal, the gain of the sled motor should be increased to obtain the track control, and this causes a fatal influence to be exerted by the DC offset.
Meanwhile, even in case of moving the whole optical pickup by driving the sled motor 108, the DC offset may cause a problem.
Specifically, a dead zone exists in the sled motor 108. The dead zone means a region where the sled motor 108 cannot move. The sled motor 108 does not move until the input voltage becomes a predetermined level due to an initial frictional force.
If a voltage less than the predetermined level is applied to the sled motor 108, the sled motor 108 does not operate even with a power consumption, and the object lens is continuously moved in the radial direction.
Accordingly, in order to quickly drive the sled motor 108, i.e., in order to make the sled motor 108 quickly escape from the dead zone, the conventional method uses the increase of the gain of the sled motor 108. However, the increase of the gain may cause a transient response.

Servo method for optical recording medium


The invention relates to flame retardants for plastics such as, for example, synthetic polymers and plastic compositions, as well as corresponding production methods and uses.

Most plastics are combustible and comparatively highly flammable. To reduce or preclude the risk of plastics burning in particular applications, it is therefore required to lower the flammability and/or to deploy flame-proof plastic compositions. For this purpose, flame retardants are usually added to the plastic with the aim of preventing igniting for a certain time or to significantly delay the spread of fire. Traditional flame retardants are based on chlorine- and bromine-containing compounds (frequently in combination with antimony trioxide), of phosphoric and nitrogenous compounds and of inorganic hydroxides. More recently, for environmental reasons, halogen-free fire proofing solutions are preferred.
EP 1 657 972 B1 relates to phosphinate complex compounds of the 2nd, 3rd, 12th and 13th groups and their use as flame retardants. In particular, phosphinate complexes of the formula

are described, in which M is one of the metals of the second, third, twelfth or thirteenth group of the periodic system of the elements;
x denotes the number 2 or 3;
R denotes a hydrogen atom or a 2 hydroxyphenyl residue;
B denotes a Lewis base;
y denotes the number 1 or 2; and
n denotes an integer from 1 to 100.
EP 2 183 314 B1 relates to phosphoric triazine compounds as fire retardants. In particular, compounds of the formula [(A-H)+]m [Mm+(HPO42−)m] and the formula [(A-H)+]m[Mm+(P2O74−)m/2] are disclosed, wherein (A-H)+ is a residue of the formula

and wherein X is H, CN, C(NH)NH2, C(O)NH2, C(NH)NHCN or its condensation product, wherein M is, independently of one another, Ca, Mg, Zn or Al and wherein m is 2 or 3.
A flame retardant composition is known from WO 2012/025362 which has at least one triazine-intercalated metal phosphate of the formula(A-H)a(+)[Mbm+(H2PO4)x1(−)(HPO4)x22(−)(PO4)x33(−)(PO3)y(−)](a−).pH2O
and comprises at least one additional flame retardant component. Here, each M is independently Cu, Mg, Ca, Zn, Mn, Fe, Co, Ni, TiO, ZrO, VO, B, Si, Al, Sb, La, Ti, Zr, Ce or Sn. The additional flame retardant component can be a metal phosphinate of the formula

wherein R1 and R2 is hydrogen or a straight-chain or a branched C1-C6 alkyl residue or a phenyl residue and Mt=Ca, Mg, Zn or Al and m=2 or 3.


The present invention relates to a multi-stage fiber amplifier in which the first and stages are connected by means including a filter for attenuating the amplified spontaneous emission. The pump source consists of a pair of light sources that are connected to a coupler that splits the power equally to two output legs. All of the pump power from the second coupler output leg is supplied to the second stage. A portion of the pump power from the second coupler output leg is converted in the first stage to amplified signal and amplified spontaneous emission, and the remainder of the power from that leg is supplied to the second stage.

The present invention relates to an optical amplifier for optical communications, and more particularly, to a multi-stage fiber amplifier in which the total available pump power, which is supplied from a single source, is optimally divided between the stages to provide maximum gain and minimum noise for a given spectral response.
High output power amplifiers are required for many applications, including, for example, multi-wavelength systems. One of the key performance characteristics of an amplifier is its output power, which is largely governed by how efficiently the pump light is converted into signal light.
FIG. 1 schematically illustrates that at the input of gain fiber 10 both the signal and the spontaneous emission (SE) are available to be amplified. The amount of SE that is amplified must be reduced relative to the amount of signal that is amplified so that signal amplification dominates in the utilization of pump power. The size of the signal is typically set by the system link loss and therefore cannot be increased. The amount of amplified spontaneous emission (ASE) could be reduced by reducing the total pump power. However, there would then be less pump power available for conversion to signal power. Since the erbium-doped fiber amplifier has utility in communication systems operating at 1550 nm, that fiber amplifier is specifically discussed herein by way of example. The invention also applies to fiber amplifiers containing gain ions other than erbium, since ASE also diverts pump power from the signal in amplifiers utilizing gain ions other than erbium. As shown by curve 18 of FIG. 2, the gain spectrum of a highly inverted erbium-aluminum-doped germania silicate fiber amplifier has a peak around 1532 nm and a broad band with reduced gain to about 1560 nm. Some prior art fiber amplifiers included means for reducing the 1532 nm peak to prevent the occurrence of such disadvantageous operation as wavelength dependent gain or gain (with concomitant noise) at unwanted wavelengths. The resultant gain spectrum might be as represented by curve 19, for example.
In one such fiber amplifier, a filter such as a fiber containing ions that absorb at the ASE wavelength is connected between two sections of gain fiber. The ASE is filtered from the output of the first gain fiber section by the ASE-absorbing fiber, and the resultant signal light is amplified by the second gain fiber section. Both the signal and pump light are introduced into the first gain fiber section, and the remnant pump light at the output of the first gain fiber section is used to pump the second gain fiber section. The lengths of gain fiber at both ends of the filter determine the amplifier gain and spectral response.
A modification of the above-described amplifier is described in the publication, R. I. Laming et al. "High-Sensitivity Two-Stage Erbium-Doped Fiber Preamplifier at 10 Gb/s", IEEE Photonics Technology Letters, vol. 4, No. 12, December 1992, pp. 1348-1340. In the fiber amplifier disclosed in that publication, the ASE absorbing fiber of the above-described amplifier is replaced by a 1536 nm isolator for suppressing the backward-traveling ASE. Since the isolator has a very high loss at the 980 nm pump wavelength, two wavelength division multiplexer (WDM) couplers are included in the circuit to provide a low-loss pump power bypass around the isolator.
Another fiber amplifier having ASE filtering is described in the publication "High Gain Two-Stage Amplification with Erbium-Doped Fibre Amplifier" by H. Masuda et al., Electronics Letters, 10 May 1990, vol. 26, No. 10, pp. 661-662. The ASE filter is connected between two fiber amplifier stages. Separate pump sources are connected to the two stages, the second stage being double pumped from two separate sources, whereby it receives more pump power than the first stage. The signal is amplified by the first fiber amplifier stage. The ASE wavelengths in the output of that amplifier are filtered, and the resultant signal is connected to the second amplifier stage. Since the input signal is relatively small, much of the pump power will be converted to ASE in the first stage. With the ASE filter in place, this ASE optical power is lost, as it does not reach the second stage. Therefore, in this type of configuration, the amount of power converted to ASE is minimized by reducing the ASE build up in the first stage by limiting the amount of pump power supplied to the first stage. In this kind of fiber amplifier, the pump conversion is enhanced, but a large number of pump sources is required.
U.S. Pat. No. 5,050,949 also teaches a two-stage fiber amplifier in which unequal pump power is supplied to each of the two stages. The gain spectrums of the two gain fibers are made different by selecting gain fibers having different host glasses and/or different gain ions. Since the gain spectrums of the two stages are different, signal gain equalization is achieved, rather than optimization of pump power conversion.

Fiber amplifier having efficient pump power utilization


A camera pedestal has a column attachable to a base. The base includes a base plate, side plates and a cover. The base and side plates are flat and are bolted together to facilitate manufacture. A cable guard system on the base has separate guard plates which can be independently shifted up and down quickly and easily by hand. A drag assembly sets a holding force on the guard plates. The guard plates have greater ground clearance at the ends away from the corners of the pedestal, to avoid contact with high points on an undulating or uneven ground surface.

The field of the invention is camera pedestals. Camera pedestals are used in production of motion pictures, video and television programs. They are most widely used in the production of television programs, in television studios. The pedestal supports the television camera. Most pedestals used in television have a telescoping column for raising and lowering the camera. Generally, they are also on wheels, so that the camera can be moved about as needed by the camera operator.
To avoid interfering with the television sound tracks, operation of all aspects of the pedestal must be very quiet. In addition, since the camera and pedestal are typically operated by a single camera operator, the pedestal should be easily operated with conveniently located controls.
Generally, various cables connect the camera on the pedestal to other equipment in the studio or sound stage. As the pedestal is moved about by the camera operator, the cables are dragged or pulled along the floor behind or along side of the pedestal. Other cables, for sound, lighting, power, etc. are usually also on the floor, and occasionally may be in the path of the camera pedestal. To prevent cables (or other obstacles) from interfering with smooth movement of the pedestal, various cable guards have been used on pedestals. While these cable guards have met with varying degrees of success, there remains a need for a pedestal having an improved cable guard, which can be quickly, easily, and quietly operated.
In the past, camera pedestals used in television studios have often been mechanically complicated, as well as costly and time consuming to manufacture and maintain. Accordingly, there remains a need for camera pedestal which can be more easily manufactured, maintained, and serviced.
To these ends, in a first aspect, a camera pedestal includes wheels attached to a base. The base preferably is a flat plate, for ease of manufacture and servicing. A telescoping column is supported on the base and has a camera platform moveable in a vertical direction. Cable guard plates on the base are slidable along guide posts in a vertical direction from an up position providing maximum ground clearance, to a down position, for increased effectiveness in preventing obstacles from interfering with the wheels.
The base is preferably triangular with a wheel or wheel pair at each corner base. The cable guard plates are advantageously, slidably attached to side plates attached perpendicularly to the base. A steering system is provided on the top side of the base. This allows all servicing and adjusting to be performed without the need for accessing the bottom side of the pedestal. The camera pedestal of the invention preferably, but not necessarily, has each of these features. Of course, each of the features may also be used separately, within the scope of the invention. The invention resides as well in sub-combinations of the features described.


A suspension system for motor vehicles includes level regulation for adjusting a predetermined height of the vehicle body. At least one piston-cylinder unit of the suspension system includes a work cylinder, a piston rod and a damping piston having damping valves. A pump is arranged between an oil reservoir and the piston-cylinder unit via corresponding inlet and outlet lines. The pump comprises a pump piston and a drive unit arranged so that a pressure of the piston-cylinder unit acts on a delivery side and on a driving side of the pump piston.

1. Field of the Invention
The present invention relates to a suspension system for motor vehicles with level regulation for adjusting a predetermined height of the vehicle body which includes at least one piston-cylinder unit with a work cylinder, a piston rod, a damping piston having damping valves, and a pump for an oil reservoir and corresponding inlet and outlet lines between the oil reservoir and the piston-cylinder unit.
2. Description of the Related Art
Suspensions with automatic level regulation for motor vehicles are known, for example, from German reference DE 32 12 433 A1 wherein the suspension units of the vehicle wheels are supplied from a central oil reservoir via correspondingly open hydraulic lines. Corresponding actuating valves connect the suspension units with the oil reservoir and are supplied with an appropriate amount of oil from the oil reservoir by a central pump. A flow regulator and a height sensor act in the oil circuit when needed to adjust the vehicle body to an appropriate height and the pump is activated in response to this flow regulator. A disadvantage in a suspension unit of this type is that hydraulic lines needed for the forward and reverse flow and the pressureless oil reservoirs require maintenance in that the filling level of the damping medium must be constantly monitored. Further, suspension units of this type cannot be retrofitted in an existing vehicle.
It is an object of the invention to provide a suspension system with level regulation which can be controlled and sensed electrically and which is also easily retrofitted in existing motor vehicles.
According to the present invention, the object is met in that a pump comprising a pump piston and a drive unit is arranged such that the pump piston is acted upon on the delivery side and on the driving side by the pressure of the piston-cylinder unit.
In the present invention, the pump piston itself provides for tightness by a close sliding fit. A slight oil leakage that occurs through the sliding fit is guided back to the oil reservoir again.
Since there are no seals acting on the pump piston, startup problems which generally occur from dynamic seals are minor even after long shelf times and with high internal pressure in the device.
The pump piston has a sliding fit relative to the pump cylinder. In this respect, absolute tightness is not required for the piston in the pump cylinder.
In another embodiment, the drive unit is provided with a cam and includes a pressure bearing for supporting a shaft carrying the cam. In this respect, the pressure in the oil reservoir is supported by the pressure bearing of the shaft when the cam is loaded toward the drive. This pressure bearing may comprise a ball bearing, thereby providing a low-friction support. Coated bearing bushes or other friction-reducing bearings may be used on the opposite side of the cam to ensure the lowest possible friction in the drive unit.
According to another embodiment, the pump is sealed relative to the piston-cylinder unit and relative to the atmosphere. Seals which seal statically and seal the housing parts relative to one another may be used for this purpose. This ensures lifetime durability of sealing.
According to yet a further embodiment, the shaft carrying the cam has at least one seal which seals toward the atmosphere.
In another embodiment, the shaft of the cam is sealed toward the atmosphere on both sides. This embodiment may be used when the shaft of the drive unit is to be loaded on both sides simultaneously so that a pressure bearing may be dispensed with.
The diameter of the shaft is approximately identical on both sides of the cam.
According to a further embodiment, a flow connection may extend from the drive side of the pump piston to the oil reservoir. In this respect, the pump piston may be pressure-compensated so that special piston ring seals may be dispensed with and so that leakage oil can easily be guided back to the oil reservoir.
The cam may be surrounded by a sliding ring which is contacted by the pump piston at the end face.
Furthermore, the sliding ring may comprise an external part of a rolling bearing.


A hydraulically actuated firing head for a tubing conveyed well perforating system includes an actuating piston responsive to a differential between tubing pressure and a sealed low pressure zone contained within the firing head. The actuating piston releases a firing piston which initiates a firing sequence.

1. Field Of The Invention
The present invention relates generally to tubing conveyed perforating systems, and particularly to such systems which are hydraulically actuated.
2. Description Of The Prior Art
One well known manner of completing an oil or gas well is through the use of a tubing conveyed completion system. A production tubing string has a packer located near a lower end thereof, and has a perforating gun suspended from the tubing string below the packer. The tubing string is lowered into place and the packer is set thus isolating the zone of the well below the packer. The perforating gun is then actuated to perforate the well casing adjacent the isolated zone and to allow formation fluid to immediately be produced up through the tubing string.
Many different techniques are known for actuating such tubing conveyed perforating guns. They can be mechanically actuated through use of a drop bar or slick line, and they can be hydraulically actuated by applying fluid pressure through a selected passageway.
It is also known to provide dual firing systems for a tubing conveyed perforating gun.
U.S. Pat. No. 4,836,109 to Wesson et al., and assigned to Halliburton Company, the assignee of the present invention, discloses a hydraulically actuated primary firing head utilizing a differential pressure actuating piston. The high pressure side of the actuating piston is communicated with well annulus pressure through a control line which extends below the packer. The low pressure side of the actuating piston is communicated with the isolated zone of the well. When the actuating piston is moved in response to an increase in well annulus pressure as communicated through the control line, a firing piston is released to initiate the firing of the perforating gun. A backup firing head is placed up on top of the primary firing head to provide an alternate means of firing the gun in the event the primary firing head fails to function or well conditions preclude the use of one of the systems after reaching total depth.
Other firing heads typical of those utilized by the assignee of the present invention include various mechanical and hydraulically actuated firing heads as shown on pages TCP-1001, TCP-1011, TCP-1013, TCP-1022, TCP-1014, TCP-1016, TCP-1020 and TCP-1018 of the Vann Systems Engineering Well Completion Product Catalog No. VS-0001 published by Vann Systems of Houston, TX, a division of Halliburton Company. Some of these structures such as the Time Delay Firing Head at pages TCP-1013, and the Pressure Actuated Firing Head at pages TCP-1022, contain a single actuating piston which also initiates the firing sequence, and is movable in response to an increase in tubing pressure.
U.S. Pat. No. 4,509,604 to Upchurch, and assigned to Schlumberger Technology Corporation discloses another pressure responsive tubing conveyed perforating system. It includes an actuating piston having its high pressure side communicated with the well annulus above the packer, and its low pressure side is communicated with the isolated zone of the well. Movement of the actuating piston releases a firing piston which initiates the firing sequence.
U.S. Pat. No. 4,523,643 to McGlothen, and assigned to Dresser Industries, Inc., discloses another hydraulically actuated tubing conveyed perforating system which operates in response to annulus pressure communicated from above the packer through a control line.

Firing head for a perforating gun assembly


A monitor/detector assembly in a synchrotron for either monitoring the position of a photon beam or detecting beam flux may additionally function as a vacuum barrier between the front end and downstream segment of the beamline in the synchrotron. A base flange of the monitor/detector assembly is formed of oxygen free copper with a central opening covered by a window foil that is fused thereon. The window foil is made of man-made materials, such as chemical vapor deposition diamond or cubic boron nitrate and in certain configurations includes a central opening through which the beams are transmitted. Sensors of low atomic number materials, such as aluminum or beryllium, are laid on the window foil. The configuration of the sensors on the window foil may be varied depending on the function to be performed. A contact plate of insulating material, such as aluminum oxide, is secured to the base flange and is thereby clamped against the sensor on the window foil. The sensor is coupled to external electronic signal processing devices via a gold or silver lead printed onto the contact plate and a copper post screw or alternatively via a copper screw and a copper spring that can be inserted through the contact plate and coupled to the sensors. In an alternate embodiment of the monitor/detector assembly, the sensors are sandwiched between the window foil of chemical vapor deposition diamond or cubic boron nitrate and a front foil made of similar material.

1. Field of the Invention
This invention relates to a monitor/detector assembly through which x-ray beams in a synchrotron are transmitted and which is used to either monitor the photon beam position or detect the beam flux for such beams, and more particularly, to a new and improved monitor/detector assembly to monitor the position of the photon beams or to detect the amount of beam flux within the x-ray beams produced in the synchrotron, the monitor/detector assembly having sensors made of low atomic number material, such as aluminum or beryllium mounted on a chemical vapor deposition diamond or cubic boron nitrate foil that also can be a barrier window.
2. Background of the Invention
High energy synchrotron radiation sources are used for research in the fields of endeavor such as the fields of material science, chemistry, physics, medical and biological imaging and geophysics. In a seven (7) GeV Advanced Photon Source (APS), high brilliance and intense synchrotron radiation is generated from insertion devices (IDs). These insertion devices include different types of magnetic wigglers and undulators. It is necessary to monitor the position of the beam so that if it is being missteered, appropriate adjustments can be made. Similarly, the amount of flux within the beam may need to be detected. In certain instances, the front end or ring side of the radiation beam developed by the APS has to be separated from the downstream or working end of the beam. This separation is accomplished through a barrier window that allows the beam to be transmitted through it while at the same time forms a vacuum barrier to separate the ring side of the beam that may be maintained at a superior vacuum level of 10.sup.-10 Torr from the downstream segment of the beam that may be maintained at a lower quality vacuum level of 10.sup.-8 to 10.sup.-6 Torr.
The cross-section of beams being produced in the APS can be visualized as having a core and a surrounding halo. The hard x-ray core of the beam is of a higher energy level than the surrounding halo and therefore can cause extremely high heat loads when it impinges on certain surfaces. On the other hand, the surrounding halo portion of the beam is of a lesser energy level and does not affect as much the surfaces on which it impinges.
In a previously designed arrangement, a photon beam position monitor (PBPM) was used to determine the position of the beam within the synchrotron. The PBPM included a plurality of spaced apart blades, each of which was formed of a chemical vapor deposition (CVD) diamond core coated with a photon sensitive metal, such as tungsten, molybdenum, titanium or a titanium alloy on the order of 1-5 microns thick. Each pair of such spaced apart blades projected in opposite directions towards each other into the path of the beams and based on the amount of energy impinging on the blades, the position of the beam could be determined.
While the positioning of the beam in the APS can be determined by such PBPM's, it would be advantageous to have a monitor/detector assembly that can be readily positioned in the path of the beam without significantly affecting the beams being transmitted through the assembly. Moreover, it would be advantageous to be able to combine in a single unit the functions performed by a barrier window that is used to isolate the front end of the beamline from the downstream end of the beamline and the PBPM. By having a single unit, only one such device needs to be mounted in the path of the beam and the costs associated with producing the devices and mounting them in the synchrotron are minimized. However, the combining of such devices into a single unit cannot be at the expense of the accuracy of the PBPM because it is important to the proper operation and use of the APS to monitor the exact position of the beam so that adjustments can be made if the beam is being missteered.
Accordingly, it is an object of the present invention to provide a new and improved monitor/detector assembly for a synchrotron for monitoring the position of the photon beam or for detecting the amount of flux in the beam.
It is an object of the present invention to provide a new and improved monitor/detector assembly for a synchrotron that functions as a barrier window between the front end and downstream segment of a beamline in the synchrotron as well as enables the monitoring of the position of the photon beam or the detection of the amount of flux in the beam.
It is another object of the present invention to provide a new and improved monitor/detector assembly for a synchrotron that provides the combined functions of a window that serves as a vacuum barrier between the front end or ring side of the beamline and the downstream segment of the beamline in the synchrotron and either a photon beam position monitor that can accurately determine the relative position of the beam within the synchrotron or a beam flux detector that can evaluate the amount of flux within the beam.
It is further object of the present invention to provide a new and improved monitor/detector assembly for use in a synchrotron that combines the functions of a barrier window with a photon beam position monitor or a beam flux detector with the window being formed of a chemical vapor deposition diamond or cubic boron nitrate foil that is fused to a base flange and the position monitor or beam flux detector including sensors of low atomic number material, such as aluminum or beryllium, that are disposed on the window foil.
A still further object of the present invention is to provide a new and improved monitor/detector assembly for use in a synchrotron that combines a barrier window with a photon beam position monitor or beam flux detector with sensors of low atomic number material, such as aluminum or beryllium, being sandwiched in between the window formed of a chemical vapor deposition diamond or cubic boron nitrate foil and a front foil of similar material.

Integral window/photon beam position monitor and beam flux detectors for x-ray beams


The invention utilizes local search engines to view a display of local business listings in order of relevance to the user. Relevance to the user depends on a variety of factors whose importance varies by user and business—these factors include distance from user-defined starting location, business size, whether or not the business is local, content provided with listing, and relevance based on user-defined search terms. The system collects and parses business information from Web pages and other sources, stores the information in a format that facilitates searches, provides a simple way for users to initiate searches, analyzes all the factors mentioned above each time a search is performed, retrieves listings in order of factor importance, and displays results to the user in order and formatted to make further inspection and use of the results easy for the user.

1. Field of the Invention
The field of the invention relates to a method of conducting searches on the internet. Specifically, computers connected to each other using common communications protocols form computer networks, the most common and ubiquitous one being the Internet. Software on connected computers can often both transmit and receive data—software that "serves" data to many other computers is often called "server" software, and computers fulfilling this role are often called servers—software that primarily receives data from servers is often called "client" software, thus forming a "client-server" relationship on a computer network. One of the most common types of "client-server" relationship is between computers used for browsing the World Wide Web and computers "serving" Web pages to such "client" computers.
Within the realm of browsing for Web pages, a common task is utilizing a search engine Website to retrieve lists of links (and associated snippets of Web page content from the Web page the links were gathered from) to other Websites that the user expects will be relevant to them based on the search terms they used to conduct the search.
Search Engine Websites employ a variety of techniques to gather and "index" (enter into their internal databases) these lists of links and attach weighted values to words found within the Website associated with the indexed link. Users then conduct searches at the Search Engine Website, and the Search Engine Website attempts to sort the results displayed to the search engine user according to a ranking factor that measures the degree to which the search terms entered by the user match the overall weighted values associated with the links listed within the search engine database. Users judge for themselves whether or not the results displayed by a search engine Website are in fact relevant for their own purposes.
Search Engine Websites therefore utilize a variety of algorithms to generate the final ranking factor for each indexed link, in the hope that their algorithms will generate ranking factors that cause the displayed records (sorted according to the ranking factor) to be judged by their users as more relevant than results displayed by other search engine Websites given the same starting search terms. One of the most popular Search Engines in use today is Google (www.google.com).
2. Detailed Description of the Prior Art
The following ten patents and published applications are relevant to the present invention.    1. U.S. Pat. No. 6,240,425 issued to John Naughton on May 29, 2001 for "Geographic Search Engine Having Independent Selections Of Direction And Distance From Relocatable Hub" (hereafter the "Naughton Patent");    2. U.S. Pat. No. 6,650,998 issued to Charles Wayne Rutledge et al. on Nov. 18, 2003 for "Information Search System For Enabling A User OF A User Terminal To Search A Data Source" (hereafter the "Rutledge Patent");    3. United States Published Patent Application No. 2005/0160014 to Andy Moss et al. on Jun. 21, 2005 for "Techniques For Identifying And Comparing Local Retail Prices" (hereafter the "Moss Published Patent Application");    4. U.S. Pat. No. 6,980,982 issued to William T. Geddes, Jr. et al. on Dec. 27, 2005 for "Search System And Method Involving User And Provider Associated Beneficiary Groups" (hereafter the "Geddes Patent");    5. U.S. Pat. No. 7,231,405 issued to Xiongwu Xia and assigned to Doug Norman, Interchange Corp. on Jun. 12, 2007 for "Method And Apparatus of Indexing Web Pages Of A Web Site For Geographic Searchine Based On User Location" (hereafter the "Xia Patent");    6. United States Published Patent Application No. 2007/0150369 to Michael A. Zlvin on Jun. 28, 2007 for "Method And System For Determining The Optimal Travel Route By Which Customers Can Purchase Local Goods At the Lowest Total Cost" (hereafter the "Zlvin Published Patent Application");    7. United States Published Patent Application No. 2008/0086460 to Kelsey Byron Stewart on Apr. 10, 2008 for "Local Search Directory Techniques" (hereafter the "Stewart Published Patent Application");    8. U.S. Pat. No. 7,457,628 issued to Brad W. Blumberg et al. and assigned to Smarter Agent, LLC on Nov. 25, 2008 for "System And Method For Providing Information Based On Geographic Position" (hereafter the "Blumberg Patent");    9. United States Published Patent Application No. 2009/0106681 to Abhinav Gupta et al. on Apr. 23, 2009 for "Method And Apparatus For Geographic Specific Search Results Including A Map-Based Display" (hereafter the "Gupta Published Patent Application");    10. United States Published Patent Application No. 2009/0106225 to Wade S. Smith et al. on Apr. 23, 2009 for "Identification Of Medical Practitioners Who Emphasize Specific Medical Conditions Or Medical Procedures In Their Practice" (hereafter the "Smith Published Patent Application").
The Naughton Patent employs the general concept of having a search engine which provides specific information based upon a geographic location of the item being searched relative to the location of where the person is performing the search or relative to a specific desired location. However, the focus of this patent deals with locating real estate within a certain geographical area and then providing the information to the user about the specific real estate in a pre-selected zone that the user is interested in locating for the purposes of sales or rental.
The Rutledge Patent discloses a system and method are disclosed for searching a data source suing text string searches in which queries and information records are qualified by temporal and/or geographical references. In an exemplary embodiment, temporal and geographical references associated with a query are the date/time the query was last submitted by a user and the user's geographical area of interest (defined by ranges of latitude and longitude coordinates), respectively. The temporal and geographical references associated with an information record are the date/time the record was last modified and the "origin" of the record, respectively. A comparison between the temporal and geographic references associated with a query and those associated with the information records in the data source permits geographically irrelevant records to be suppressed and allows an individual user to receive only information that has been modified since the user last requested it. Thus, search results are automatically pre-filtered prior to transmission to the user thereby conserving network resources and reducing the amount of context-based filtering required of the user.
The Moss Published Patent Application discloses a computer software algorithm which relates to the aggregation and use of local retail information for the purpose of providing a wide variety of valuable services to consumers and retailers. The invention relates to providing services which help consumers find and compare the best prices of promotions for products at their local retail stores. The search interface is presented by which a consumer can identify a first price for a product offered by a first vendor in a geographic area. The search also aggregates local retail information and the retail information includes geographic location information for corresponding retailers. At least the portion of the retail information is retrieved and stored in a database index by the geographical location where the prices for the same product from other retailers in the area are also listed to enable consumers to determine the best price for the product in the area they are searching.
The Geddes Patent discloses a search system and method provide a user with a fast and efficient way to progressively expand a search for providers of a specified search object, such as a good, service, or information; while maintaining a desired link to a beneficiary group including a particular geographic community, a community of interest, or a user-preferred class of providers. More specifically, the user and/or provider is initially associated with at least one of a plurality of beneficiary groups, such as a local church for example, for searching for a provider associated with a user-specified beneficiary group or groups. Thus, a user may conduct a targeted search for a specified search object from providers associated with a similarly specified beneficiary group. The search or beneficiary group can thereafter be expanded by the user, until the user selects a provider of the user-specified good, service, or information, associated with the user-specified beneficiary group(s).
The Xia Patent discloses a method and apparatus of indexing web pages of a web site for geographical searching based upon user location. The patent discloses a local search engine geographically indexes information for searching by identifying a geocoded web page of a web site and identifying at least one geocodable web page of the web site. The system identifies a geocode contained within content of the geocoded web page of the web site. The system indexes content of the geocoded web page and content of the geocodable web page. The indexing including associating the geocode contained within content of the geocoded web page to the indexed content of the geocoded web page and the geocodable web page to allow geographical searching of the content of the web pages.
The Zivin Published Patent Application discloses a method and system for providing customers with means to determine a) how far the customer should be willing to travel to a vendor to purchase locally sold goods and b) what routes the customer should take to minimize his or her total costs. Customers use an Internet search engine to find products or services that they are interested in purchasing in their local area. The search results provide a list of goods along with their current price and store location. Customers select one or more goods they are interested in purchasing and add these goods to a shopping list. A recommendation is provided based on variables such as the customer's estimated value of time, traffic conditions, gas prices, parking fees, automobile miles per gallon, the difference in prices between stores, or other relevant variables. The recommendation informs that customers as to vendors at which he or she should purchase goods and the order in which the locations should be visited so as to minimize total purchase costs.
The Stewart Published Patent Application discloses various technologies and techniques are disclosed for providing and/or facilitating local searching. Basic information is imported from an external data provider about the businesses that are located in a particular locality. A customization feature allows each business to optionally add additional details to a respective business profile associated with the basic information. A categorized grouping of the businesses is created based at least in part upon the basic information. A web site is provided that allows an end user to access a local search directory containing at least the basic information about the businesses. Businesses are included in the directory without having to register. Search engines can use the categorized business directory to retrieve business information limited to a particular locality. A list of matching information is provided to the search engine for use by the search engine in responding to a user request.
The Blumberg Patent discloses a system and method for providing position information using a three-dimensional based grid is provided. The position information may be relayed to an electronic device by providing location information to a database and receiving location-centric information at the electronic device. The system may include a network for continuously updating the database in real-time.
The Gupta Published Patent Application discloses a method and apparatus for geographic specific search results in response to a search request having an address field includes retrieving map portion having the address thereon. The method and system further includes determining entities in geographic relation to the address and generating an entity listing, where the entity listing includes listing of the various entities. These entities may represent any type of business, club, library, government building/office, or other locations. The method and apparatus further includes determining various descriptive terms that relate to the entities which are in geographic relation to the address. These terms include hyperlinks to corresponding entity listings. The method and apparatus further includes generating a visual display that includes: the map portion with the address displayed thereon; an entity portion that includes the entity listing; and a term portion with a taxonomical display of the plurality of terms.
The Smith Published Patent Application discloses a scheme enables the identification of medical professionals having expertise with a particular medical condition or procedure. Areas of expertise are assigned to both conditions and procedures and medical professionals who treat the condition or perform the procedure. A description for treatment is received and used to identify a specific condition or procedure. Upon identification of the condition or procedure, the areas of expertise assigned to the condition or procedure are retrieved. Medical professionals who also have assigned one or more of the retrieved areas of expertise are then identified.
There is a significant need for an improved search engine which enables local businesses to be listed at the top of the search.

Method of conducting searches on the internet to obtain selected information on local entities and provide for searching the data in a way that lists local businesses at the top of the results


This invention relates to an anode assembly for a magnetron used to generate microwaves in a microwave oven. An object of the invention is to inexpensively prevent the generation of gas due to impurities within the active space within the anode assembly. Such gas can interfere with the movement of thermally excited electrons within the active space and thereby cause abnormal oscillation of the microwave energy output. In the invention, the surfaces of the magnetron's hollow anode cylinder and plate-shaped anode vanes are made of electrical-grade copper with a coating of oxygen-free copper having an extremely low impurity content.

1. Field of the Invention
This invention relates to an anode assembly for a magnetron used in a microwave oven, which is usually referred to as an electronic range, to generate microwaves for cooking foodstuffs contained in the oven.
2. Description of the Prior Art
Conventional magnetrons are illustrated in FIGS. 1 and 2 of the accompanying drawings. Such conventional magnetrons comprise a direct-heated filament(referred to as a cathode) 1 disposed axially at its central position and an anode cylinder (referred to as an anode) 2 which is an anode structure mounted in a radially outwardly spaced, in surrounding relation to the cathode.
In addition, the magnetron includes a magnetic circuit comprising a magnet 4 (see FIG. 1) and a magnetic pole 5 and provided within a yoke 3 (see FIG. 1) serving as a frame, to apply a magnetic flux into an active space 12 defined between the filament 1 and the anode cylinder 2; an output section comprising an antenna lead 6, an antenna seal 7, an ceramic insulator 8 and an antenna cap 9 (see FIG. 1) for emitting microwave energy transferred from the anode cylinder 2 to the exterior of the magnetron; radiation fins 11 (see FIG. 1) for radiating heat resulting from collision of thermally excited electron with a plurality of vanes 10 disposed radially on the inner periphery of the anode cylinder; and a filter circuit for preventing an unnecessary high frequency component produced in the active space 12 from flowing back to a power source.
When the magnetron thus constructed performs oscillating operation, the thermally excited electron emitted from the filament 1 effect cycloidal movement as they undergo the force of an electric field induced between the vanes 10 and the filament 1 and the magnetic flux applied into the active space 12 between the vanes 10 and the filament 1 and the magnetic flux applied into the active space 12 between the filament and the anode cylinder by the magnetic pole 5 of the magnetic circuit. The thermally excited electron thus accelerated generate the microwave energy which will be received by the vanes 10. The microwave energy transferred to the vanes is emitted through the antenna lead 6 of the output section to the exterior of the magnetron to dielectrically heat and cook the foodstuffs placed within the microwave oven.
The anode cylinder 2 and the anode vanes 10 constituting the anode assembly for the magnetron are made entirely of an expensive material having extremely low impurity content, such as oxygen-free copper. However, use of the expensive oxygen-free copper for making the anode cylinder 2 and the anode vanes 10 causes increase of the cost of the magnetron, while the electrical-grade copper used for the parts results in generation of gas due to a small quantity of the impurities emitted into the active space of the anode assembly. The gas may interfere with the movement of the thermally excited electron, thereby causing abnormal oscillation or a moding phenomenon in which a pattern of the microwave mode in the active space is not maintained constantly.

Anode assembly for a magnetron covered by an oxygen free copper film


A cover member of a gas supply manifold has a bent rising wall portion that is formed by bending a part of the cover member so as to rise in an opposite direction of a main body. The bent rising wall portion is in a form of a loop surrounding the entire circumference of a gas supply flow path and an area around the gas supply flow path. Such configuration increases the rigidity of the cover member and prevents large distortion of the cover member and leakage of gas from the gas supply flow path. As a result, the thickness of the cover member is reduced and the weight and the production cost of the gas supply manifold are also reduced.

Field of the Invention
The present invention relates to a gas supply manifold for use in a constitutional element of a gas powered water heating apparatus and a gas combustion device provided with the gas supply manifold.
Description of the Related Art
Generally, a gas combustion device provided for a gas powered water heating apparatus has a plurality of burner heads (combustion pipes) for burning fuel gas arranged in a burner case and fuel gas is supplied from a gas supply manifold into the burner heads.
The gas supply manifold is disclosed in, for example, Patent Literatures 1 and 2. The gas supply manifold disclosed in these Patent Literatures has a main body provided with a plurality of gas injection nozzles and has a cover member overlapped on the main body via a sealing packing. The cover member constitutes a gas supply flow path between the cover member and the main body and is fastened to the main body with a screw. The cover member and the main body are manufactured by pressing a metal plate.
In such a configuration, the number of members and the production cost of the gas supply manifold are reduced. In addition, the gas supply manifold is made thin and the weight is reduced.
However, there is still room for improvement in the related art as mentioned below.
It is desired that the production cost of the gas supply manifold be further reduced and the weight reduction be further promoted comparing with the related art. For this purpose, the thickness (sheet thickness) of the cover member can be reduced. However, when the thickness is merely reduced, the cover member easily twists and causes deformation such as warp. Such deformation causes leakage of fuel gas out of the gas supply flow path formed between the cover member and the main body. Therefore, there is need for appropriately preventing such problems.
The number of screwed portions of the cover member to the main body can be increased for suppressing warp and deformation of the cover member. In such a case, the screwing procedure becomes complicated and the production cost increases. Further, even when the number of the screwed portions is increased, it is difficult to adequately suppress warp and deformation of the cover member.

Gas supply manifold and gas combustion device provided with the same


A method of electrically testing an electrical component containing a plurality of networks with at least one node. The method uses segmented, charge limiting testing to charge the nodes and detect shorted or disconnected nodes while preventing accumulated charges in the networks from making uncharged nodes appear charged. The method is well suited for voltage contrast electron beam testing of unpopulated high density multichip modules and interconnect substrates.

1. Field of the Invention
The present invention is directed to a method of electrically testing an electrical component containing a plurality of networks with at least one node. More particularly, the invention uses segmented, charge limiting testing to charge the nodes and detect shorted and disconnected nodes while preventing accumulated charges in the networks from making uncharged nodes appear charged.
2. Description of Related Art
Advanced substrate fabrication strategies require judicious use of in-process final test and inspection tools. Automatic test and inspection techniques continually need to be improved to match increasing complexity of advanced electrical components. In addition, test and inspection are often keys in reducing costs and increasing functionality of electrical networks in electrical components.
High packaging densities require finer line and pad size and more wiring levels of interconnection networks in order for a single component to have 10,000 chip-to-board interconnect bonding pads. To reduce costs and increase yields it may be necessary to verify the correctness of each process step where many such steps are used to produce the final component. Electrical testing of sub-assemblies as well as the completed components becomes increasingly difficult as the density of the networks increases and the dimensions of pads decrease. As a result, conventional methods of mechanical probing such as flying probe or bed-of-nails testers are not likely to meet reliability and cost effectiveness standards. New techniques are needed to replace expensive, delicate and short lived mechanical probes that may damage the component being tested.
One such technique is voltage contrast electron beam testing. Electron beams can charge networks of pads within unpopulated substrates as well as dynamically sense (read) the electrical potential of the pads. This discrimination between charged and uncharged pads allows for detection of shorts and disconnects (opens). Voltage contrast electron beam testing requires that the beam be accurately vectored to probe the nodes where it must charge the nodes or measure the node voltages uniformly over large areas. Further, before testing and between complete test sequences an electron flood gun must uniformly remove the charges from the component. The physics of electron beam interactions with various substrate materials governs the ability to charge, read voltage, and erase charge in the materials. Beam parameters must be determined for each set of conductor/insulator substrate materials. Charge retention by the conductor networks must exceed testing times and inadvertent contamination can cause unacceptable leakage resistances. Therefore, substrate material condition, cleaning methods, and conditioning requirements must be specified. Advantageously, electron beams can be positioned by rapid electromagnetic or electrostatic deflection systems based on CAD data alone. Furthermore, electron beams have been used for pad sizes below 100 microns and pad numbers of several tens of thousands. For instance, in "A Dynamic Single E-Beam Short/Open Testing Technique," Scanning Electron Microscopy/1985/III (pages 991-999) Brunner et al. report that on a module containing 30,000 pads the charge and read times summed up to less than one minute. Thus, electron beams are an effective tool for testing a wide variety of printed circuit boards, multichip modules, substrates and other electrical components. Voltage contrast electron beam systems are disclosed, for example, in U.S. Pat. Nos. 4,829,243 to Woodard et al. and 4,843,329 to Beha et al.
For a more complete understanding of the present invention, it is necessary to discuss a few related test algorithms. A one-pass test method (nodes tested once for shorts and once for opens) well suited for electron beam testing is taught by R. Schmid et al. in "Design and application of an e-beam test system for microwiring substrates,"34th Electron, Ion and Photon Beams Conference, R2, May 29, 1990. Another one-pass test method is disclosed by Myers et al. in U.S. Ser. No. 07/631,111 filed Dec. 20, 1990. Such one-pass algorithms are generally performed by charging a node in a first network and testing the other nodes in the first network for being uncharged (disconnected or open), testing each node in a second network for being charged (shorted) and then charging one node in the second network and testing the remaining nodes in the second network for being uncharged, and repeating this procedure for the remaining networks until either all the nodes have been tested or a defect has been found. Such one-pass tests are relatively fast but ascertain only the existence of opens or shorts in the component.
The necessity of determining the location of any defect depends on the purpose of conducting the test. Various test purposes include (1) determining whether the part is good or bad; (2) identifying bad networks; and (3) a complete functional description of network interconnection. The one-pass open and short testing procedure described above can be employed to discriminate good substrates from bad substrates, which may be sufficient in many cases as the occurrence of defects may be infrequent. The one-pass test which effectively is a simple open and short test may be sufficient particularly where the substrate needs to be labelled good or bad but fault location is not required. The one-pass test may be advantageous since the relatively few decisions, measurements, and charge excitations permit rapid testing. In addition, the one-pass test can be discontinued after the first defect is detected. However, it may be desirable to more fully test the networks to detect more of the defects therein in order to provide further fault information. Myers et al. disclose a two-pass test to provide such information. The first pass comprises the above-mentioned one-pass test with a few additional steps. The second pass algorithms are relatively complicated and shall not be described herein. To summarize, the two-pass tests determine which of the networks are defective; the more sophisticated two-pass test also determines precisely how the faulty nodes or networks are connected and thus details all functional faults.
Unfortunately, performing such tests with electron beam and voltage contrast equipment to detect opens and shorts may cause charge buildup in high density multichip modules. As more and more electrical networks are charged to find opens and shorts, the electrical potential of other networks rises. Depending on the density and design of the multichip module, it is possible for the potential of nodes in the networks which have not been charged to appear as shorted when, in fact, they are not. This drawback is hereinafter referred to as the "accumulated charge effect." Needless to say, there is a need for a charge limiting test algorithm which overcomes the accumulated charge effect.

Segmented charge limiting test algorithm for electrical components

Microelectronics and Computer Technology Corporation


An improvement in a coin operated vending machine for vending bulk articles comprises means for deflecting loose articles away from the entrance to the dispensing aperture. The means comprises a resilient rolling member, extending across an entry notch to a housing shielding the aperture, and rotating in a direction opposite to the direction of revolution of an advancing dispensing wheel, thus gripping and ejecting loose articles in the vicinity of the entry notch.

Coin operated vending machines for dispensing bulk merchandise, so-called "bulk vendors", are widely used to dispense small vendible items. The dispensing mechanism utilized in conventional bulk vendors requires that the merchandise being dispensed have a relatively uniform configuration approximating a sphere or a spheroid. Thus, merchandise such as gumballs are ideal for vending from a bulk vendor, because of their smooth spherical configuration. However, dispensing non-spherical articles such as packages of chewing gum, novelty items and the like from a bulk vendor requires that each article be individually packaged in a rigid capsule of more or less spherical or spheroidal configuration.
A typical bulk vendor of the type heretofore known is described in U.S. Pat. No. 4,534,492, the specification of which is incorporated herein by reference. The conventional dispensing mechanism utilized in bulk vendors of this type includes means positioned above a revolving dispensing wheel, which permits the passage through a dispensing aperture of only those items carried in containers formed in the dispensing wheel while excluding other loose articles contained in the product bin. Such means conventionally comprises a housing having a notch facing opposite to the direction of revolution of the dispensing wheel. An article carried in one of the containers formed in the dispensing wheel passes through the notch as the wheel advances, and as the container comes into alignment with the dispensing aperture the article is dispensed through a delivery chute, while loose articles contained in the product bin are deflected away from the dispensing aperture by the housing. Thus, for each coin inserted the bulk vendor dispenses only the article or articles carried in a single container of the dispensing wheel.
To assist in deflecting loose articles away from the aperture, a series of resiliently flexible members, typically springs, have been used to form a resilient curtain across the entry notch in the housing. An article seated in a container will deflect the springs sufficiently to enable passage of the article through the entry notch to the interior of the housing, permitting access to the dispensing aperture, while other loose articles contained in the product bin cannot deflect the springs sufficiently to enter the housing and are thus deflected over the exterior of the housing and remain in the product bin.
The main disadvantage to such conventional bulk vendors is that they are useful only for dispensing articles comprising a rigid capsule. Soft capsules carried on top of the dispensing wheel, entrained in the flow of product outside of the containers, tend to deform as the springs are deflected, and partially enter the entry notch along with an article carried in the container. Because the soft capsule is flexible, rather than being deflected over the housing as the dispensing wheel revolves the article is forced into the notch. This deflects the springs toward the inside of the housing, forming a "V"-shaped entry passage which converges in the direction of revolution of the dispensing wheel. As the wheel advances, the loose article becomes wedged against the dispensing wheel, crushing the capsule of both the article carried in the container and the loose article carried on top of the dispensing wheel. The soft capsule is easily deformed and collapsed in the notch, blocking the entry to the housing, and eventually jams the vendor. Since the dispensing wheel revolves in only one direction, the crushed article can only be removed by maintenance personnel, until which time the vendor remains out of service. The merchandise contained in the capsule can be mutilated beyond salvage in the process.
The rigid capsule typically used to package non-spherical vendible articles is formed in two portions. The article is deposited into the receptacle portion and the closure portion is then manually attached. The thickness of plastic required to maintain rigidity in the capsule, and the need to manually seal the portions of the capsule together, give rise to considerable expense in the production of vendible articles. This increases the cost of each article dispensed from the vendor. Moreover, since the purchaser's interest is in the article within the capsule, the capsule itself is generally discarded after purchase, which results in considerable wastage of non-biodegradable materials.
It is accordingly extremely advantageous to be able to dispense from a bulk vendor non-spherical merchandise packaged in a soft plastic capsule. A typical soft capsule is composed of polystyrene and has a vacuum formed receptacle portion into which the merchandise is deposited. The capsule is sealed by heat sealing a plastic or metal foil closure portion onto the filled receptacle portion. The entire packaging process can thus be effected by machine, and the capsule itself is recyclable and utilizes considerably less plastic than the rigid capsules required by conventional bulk vendors. Overall the cost of packaging merchandise in the soft capsule can be one-third or less of the cost of packaging in a rigid capsule.
The present invention overcomes this disadvantage by providing a bulk vendor capable of dispensing merchandise contained in a soft capsule. This is accomplished by replacing the resilient flexible members forming a deflecting curtain over the entry notch with a resilient rolling member. The rolling member extends across the entry notch and rotates in opposition to the revolution of the dispensing wheel, preferably at a speed slightly greater than that of the dispensing wheel.
An article carried in the container of the dispensing wheel will pass underneath the rolling member with minimal deflection thereof. However, loose articles contained in the product bin, when urged toward the entry notch by the advancing dispensing wheel, are frictionally engaged by the rolling member and ejected over the top of the housing. By employing a resilient rolling member which rotates in opposition to the dispensing wheel, and thus actively ejecting loose articles away from the vicinity of the entry notch (rather than using resilient members which merely passively deflect articles away from the notch) the bulk vendor embodying this improvement is able to dispense merchandise in a soft capsule without jamming or deforming the capsule. The bulk vendor embodying this improvement is thus able to vend merchandise at a substantially lower cost than conventional bulk vendors, and results in considerably less wastage when the capsule is discarded by the purchaser.


The present invention relates generally to body tissue fixation systems, including body tissue fixation hardware comprising biocompatible, bioabsorbable (resorbable) thermoplastic plates, and methods of using those systems and hardware.

Traditional orthopedic and traumatological fixation systems to facilitate bone fracture healing (osteosynthesis) typically employ metallic hardware, e.g., plates, screws, rods and the like, formed of biocompatible, corrosion resistant metals such as titanium and stainless steel. Typical metallic plates are described, e.g., in the book, F. Sequin and R. Texhammar, AO/ASIF Instrumentation, Springer-Verlag, Berlin, Heidelberg, 1981, at p. 21-22, 55-79, 107-108, 117-122, the entire disclosure of which is incorporated herein by reference. While such systems are generally effective for their intended purposes, they possess a number of inherent shortcomings. For example, metal release to the surrounding tissues has been reported. See, e.g., L.-E. Moberg et al. Int. J. Oral. Maxillofac. Surg. 18 (1989) at pp. 311-314, the entire disclosure of which is incorporated herein by way of this reference. Other reported shortcomings include stress shielding, see P. Paavolainen et al., Clin Orthop. Rel. Res. 136 (1978) 287-293, the entire disclosure of which is incorporated herein by way of this reference, and growth restriction in young individuals, see K. Lin et al, Plast. Reconstr. Surg. 87 (1991) 229-235, the entire disclosure of which is likewise incorporated herein by way of this reference. In infants and young children, there is the risk that metallic plates and screws can sink into and below the cranial bone, as a consequence of skull bone growth, thereby threatening the brain. See, e.g., J. Fearon et al., Plast. Reconstr. Surg. 4 (1995) 634-637, the entire disclosure of which is incorporated herein by way of this reference. Therefore, it is generally recommended that non-functional implants should be eventually removed, at least in growing individuals. See C. Lindqvist, Brit. J. Oral Maxillofac. Surg. 33 (1995) p. 69-70, the entire disclosure of which is incorporated herein by way of this reference.
Especially in maxillofacial and in cranial surgery, metallic mini plates are popular for use. See e.g., W. Muhlbauer et al., Clin. Plast. Surg. 14 (1987) 101-111; A. Sadove and B. Eppleg. Ann. Plast. Surg. 27 (1991) 36-43; and R. Suuronen, Biodegradable Self-reinforced Polylactide Plates and Screws in the Fixation of Osteotomies in the Mandible, Doctoral Thesis, Helsinki University, Helsinki, 1992, p. 16, and references therein, the discloures of which are incorporated herein by reference. Mini plates are small, thin, narrow plates, which have holes for screw fixation. They are typically located on bone, perpendicularly over the fracture to fix the bone mass on both sides of the fracture to each other. Typical geometries of mini plates are described e.g. in U.S. Pat. No. 5,290,281 at FIGS. 6A-6F, the entire disclosure of which is incorporated herein by way of this reference.
The main advantage of metallic plates (like titanium, stainless steel and cobalt chrome molybdenum plates), is that they are strong, tough and ductile so that they can be deformed or shaped (e.g., bended) at room temperature in the operation room, either by hand or with special instruments, to a form corresponding to the surface topography of bone to be fixed. In this way, the plate can be fixed flush on the bone surface to which the plate is applied.
In light of the above shortcomings of metallic plates, however, bioabsorbable plates have been developed for fracture fixation. Longitudinal, six-hole plates were developed for orthopaedic animal studies. See Eitenmuller et al., European Congress on Biomaterials, Abstracts, Instituto Rizzoli, Bologna, 1986, p. 94, the entire disclosure of which is incorporated herein by this reference. However, because of their inadequate strength, some of the plates were broken in animal experiments involving fracture fixation.
A special advantage of bioabsorbable plates is that they can be provided with openings for the insertion therethrough of surgical fasteners (like screws), while allowing means to permit the formation of additional fastener openings therethrough during a surgical procedure at the surgeon's discretion, as has been described in European Patent specification EP 0 449 867 B1, the entire disclosure of which is incorporated herein by way of this reference.
The main disadvantage of prior art bioabsorbable plates is that they can be deformed (bended) permanently and safely only at elevated temperatures above their glass transition temperature (T.sub.g), as has been described e.g. in EP 0 449 867 B1 and in U.S. Pat. No. 5,569,250, the entire disclosures of which are incorporated herein by way of this reference. Below their T.sub.g, the prior art bioabsorbable plates are brittle and break easily when deformed. Only at temperatures above the T.sub.g does the molecular structure of prior art plates have enough mobility to allow shaping (e.g., bending) without the risk of breaking. Accordingly, U.S. Pat. No. 5,569,250 describes a biocompatible osteosynthesis plate that is capable of being used in a secured relationship over a plurality of adjacent bone portions. That biocompatible osteosynthesis plate includes an elongated section having a top face and a bottom face, at least one fastener opening disposed between the top face and the bottom face, and means disposed upon the elongated section to permit the formation of additional fastener openings therethrough, during a surgical procedure. The osteosynthesis plate is in a first thermochemical state in a first configuration and is capable of being converted to a second thermochemical state so that it may be deformed prior to fixation. The first thermochemical state is typically room temperature (operation room conditions) and the second thermochemical state is typically an elevated temperature above the T.sub.g of the polymer material (e.g., for polylactides between 50-60.degree. C.). Accordingly, in order to shape the plates disclosed in U.S. Pat. No. 5,569,250, they must be changed from their first thermochemical state to the second thermochemical state by heating, and thereafter they must be changed again back to the first thermochemical state prior to fixation. Because the thermal conductivity of polymeric materials is poor, the conversion of material to a second temperature is a slow process. Therefore, the clinical use of plates of U.S. Pat. No. 5,569,250 is tedious, slow and complex, especially if the surgeon must shape the plate several times to make it fit exactly to the form of the bone to be fixed.
K. Bessho et al., J. Oral. Maxillofac. Surg. 55 (1997) 941-945, the entire disclosure of which is incorporated herein by reference, described a bioabsorbable poly-L-lactide miniplate and screw system for osteosynthesis in oral and maxillofacial surgery. However, in order to shape the plates of that reference, they first must be heated by immersion in a hot sterilized physiologic salt solution or by the application of hot air until they become plastic, and only then can they be fitted to the surface of the bone.
EP 0 449 867 B1 describes a plate for fixation of a bone fracture, osteotomy, arthrodesis etc., said plate being intended to be fixed on bone at least with one fixation device, like a screw, rod, clamp or corresponding device, wherein the plate comprises at least two essentially superimposed plates to provide a multilayer plate construction. The individual plates of said multilayer plate construction are flexible, so as to permit a change of form of said multilayer plate construction to substantially assume the shape of the bone surface in the operation conditions by means of an external force, such as by hand and/or by bending instrument directed to said multilayer plate construction, whereby each individual plate assumes a position of its own with respect to other individual plates by differential motion along the respecitive surfaces of coinciding plates.
Although the said multilayer plate fits even the curved bone surface without heating of individual plates, the clinical use of multilayer plates is tedious, because the single plates easily slip in relation to each other before fixation. Additionally, the thickness of multilayer plate system easily becomes too thick for cranio maxillofacial applications, causing cosmetic disturbances and increased risks of foreign body reactions.
U.S. Pat. No. 4,671,280, the entire disclosure of which is incorporated herein by reference, describes the manufacturing of a fastener member or staple, by the winding of an oriented bioabsorbable polymeric filament around a forming bar, which winding is carried out at a temperature below the glass transition temperature of the polymer. Ordinarily, winding will be done at ambient temperature. Because the oriented filament is quite stiff, the coils are bowed out slightly from the sides of the forming bar. Thus, the coils do not fully assume the desired fastener member (or staple) configuration until the filaments are heated, which will normally be done during the annealing step (see, e.g., U.S. Pat. No. 4,671,280; Column 5, first two paragraphs). Thus, while U.S. Pat. No. 4,671,280 may describe some bending of drawn filament at an ambient temperature, the bending does not give the desired configuration of the material until the filaments are additionally heated. The filaments are heated during the annealing step to a temperature above the glass transition temperature of the material (see also Example 1 of U.S. Pat. No. 4,617,280).
A need, therefore, exists for a bioabsorbable (bioresorbable or biodegradable) osteosynthesis device, like a plate, which is thin and substantially rigid and substantially deformable at a first thermochemical state, being also dimensionally stable before and after deformation (shaping) in the said first thermochemical state. A need also exists for a bioabsorbable (bioresobable or biodegradable) osteosynthesis plate, which is strong, tough, does not produce a substantial inflammatory response, and which plate can be deformed, yet dimensionally stable at temperatures below the glass transition temperature (T.sub.g) of the material from which the device is made, to facilitate shaping. A need further exists for such a bioabsorbable (bioresorbable or biodegradable) osteosynthesis plate, which is strong, tough, does not produce a substantial inflammatory response, and which plate can be deformed, yet dimensionally stable at room temperature in operation room conditions, to facilitate the shaping of the plate. Likewise, a need exists for such a bioabsorbable (bioresorbable or biodegradable) osteosynthesis plate, which is strong, tough, does not produce a substantial inflammatory response, and which plate can be deformed, yet dimensionally stable in operation room conditions (in the first thermochemical state) to allow its fixation on bone without distortion of the configuration of the bone fragments to be fixed, and which shaped plate is also dimensionally stable at a second thermochemical state, in tissue conditions, when fixed on bone surface to facilitate non-problematic bone fracture healing.

Bioabsorbable, deformable fixation plate