Method and apparatus for the formation of granules of a larger size or mass of a desired range from a feed stock of smaller particles comprising feeding a meltable powdery material to be granulated, or a non-meltable powdery material with a meltable binder to the surface of a rotating spreader means in the form of a disk or bowl, at least a portion of which has been heated to a temperature above the melting point of the meltable component of the feed material wherein the rate of feeding, the energy input to the spreader means and the rotational speed of the spreader means are controlled so that there is sufficient time for at least a partial melting of the meltable component of the feed material substantially solely by contact with the heated surface of the spreader means, centrifugally spreading the material across the surface of the disk or bowl and dispersing the same from the edge thereof into an atmosphere cooler than the melting temperature to form the granulated product. For certain materials only a part of the powdery feed material is melted forming a liquid film carrying a major portion of substantially unaffected or minimally affected feed material to produce a product comprising individual granules containing a core as the major part of each granule with the original powdery material essentially unchanged maintained in self-sustaining form by a matrix of melted and resolidified particles bonded to each other at their surface.

1. Technical Field
The present invention is related to a method and apparatus for rapid granulation of particles, and to the resulting product. More particularly, the present invention is related to the formation of granules or particles of a larger size or mass of a desired range from a feed stock of smaller particles.
2. State of the Art
There are numerous techniques available for granulation of particles. A general review of current methods of granulation can be found in Chapter 7 of the "Handbook of Powder Science & Technology", edited by Fayed et al and published in 1984 by Van Nostrand Reinhold Co., New York.
Agglomeration or granulation of smaller or finer particles into relatively larger or bigger sized masses is desirable for several reasons. For instance, when microencapsulation or coating of fine particles is necessary to control the release or interaction of these particles into or with the surrounding medium or environment, it may be advantageous to have these fine particles compacted or clustered into larger sized masses so as to reduce the total interacting surface area. In other situations, the material is available only in smaller particle size than could be tolerated or used in a particular application or could be readily handled for further processing, e.g., filling capsules with a pharmaceutically active material in difficult to handle fine powdered form as originally synthesized. Other reasons for granulation may be related to esthetics, rheology or safety, e.g., preventing dust explosions or inhalation of toxic or allergenic materials, ease of conveying, prevention of caking, increasing bulk density, facilitating removal of solids from liquids or gases, separation of one kind of solid from another by size differential after processing, etc.
The methods or apparatus heretofore employed for granulation or agglomeration and clustering of fine particles such as powdered materials suffer from certain limitations or disadvantages. Some devices, for instance, tablet Presses have a lower size limit (about 1/8 inch) and a limit on the production rate (several thousand pieces per minute). Roll pressing and extrusion requires expensive precision equipment subject to wear and tear. Equipment of this nature may also have a product size limitation similar to that of tablet presses. Agitation methods include pan mixers, paddle mixers, inclined discs, rotating drums and the like. These methods as used by the prior art often suffer from low production rates and have high space requirements. On the other hand, those processes which employ spray drying tend to be expensive due to high energy cost. Prilling is generally limited to materials stable in molten form and to particles above 1 mm in diameter. Fluid bed granulation has high space requirements and the energy costs are also high.
Of special concern is the ability to granulate particles of materials which are easily decomposed or degraded, or which become sticky for a period of time after being melted and cooled. Most materials have a melting point as well as a decomposition temperature. Particularly difficult to deal with are materials which decompose or are otherwise deleteriously affected by temperatures close to, or at, the melting point. In general, however, it has been found that such decomposition results not only from reaching a particular temperature, but also from being maintained at that temperature for a particular length of time which may vary from one material to another. Many prior art granulation techniques fail to recognize this critical concept resulting in the inability to granulate or spray cool certain materials with conventionally available techniques because of the maintenance of the materials at the undesirable temperature for an excessive period of time. Frequently, for example, feed materials will be melted in their entirety and then fed as a liquid to a rotating disk or the like for centrifugal dispersion as in spray cooling. The resultant product from such techniques may be totally unacceptable in that it is "sticky" or otherwise difficult to handle for further processing, or important characteristics of the starting material may be effectively decreased or destroyed by such treatment.
Thus, a need for an improved, efficiently simple and cost effective granulation and spray-cooling process and apparatus, and particularly one that is sufficiently fast to be capable of handling especially thermally sensitive materials, is quite apparent.

Washington University Technology Associates, Inc.


A thermoplastic polycarbonate composition comprising: 10 to 30 wt % of a brominated polycarbonate; 10 to 80 wt % of a homopolycarbonate; optionally, 1 to 60 wt % of an aromatic poly(ester-carbonate) comprising carbonate units derived from bisphenol A, resorcinol, or a combination thereof, and ester units derived from a bisphenol, preferably bisphenol A, or resorcinol, and terephthalic acid, isoterephthalic acid, or a combination thereof, wherein a molar ratio of carbonate units to ester units ranges from 1:99 to 99:1; 5 to 15 wt % of a core-shell impact modifier; 1 to 10 wt % of an α,β-unsaturated glycidyl ester copolymer impact modifier; 0.01 to 1 wt % of a hydrostabilizer, preferably an epoxy hydrostabilizer; optionally, 0.1 to 10 wt % of an additive composition; wherein the wt % of each component is based on the total weight of the composition, which totals 100 wt %.

This disclosure relates to thermoplastic polycarbonate compositions, and in particular to thermoplastic polycarbonate compositions, methods of manufacture, and uses thereof.
Polycarbonates are useful in the manufacture of articles and components for a wide range of applications, from automotive parts to electronic appliances. Because of their broad use, particularly in electrical applications, it is desirable to provide polycarbonates with improved hydrolytic stability and electrical tracking resistance.
There accordingly remains a need in the art for thermoplastic polycarbonate compositions that have improved hydrolytic stability and electrical tracking resistance. It would be a further advantage if thermoplastic polycarbonate compositions had improved impact resistance, thermal properties, and flame retardance.

Thermoplastic polycarbonate compositions with improved hydrolytic stability and electrical tracking resistance and shaped articles thereof


A doorbell cam device for controlling access to a listing includes a microprocessor, a video interface, an input interface, a wireless network interface, an audio interface and a special computer program. The doorbell cam device is adapted to scan a machine readable optical label encoding a showing appointment, request a showing appointment management system to validate the showing appointment, receive a validation result, and notify an electronic lock system to open when the showing appointment is validated. The opened electronic lock system provides access to the listing for a user presenting a showing pass scanned by the video interface. The scanning can be triggered by a double-press of the input interface.

Mechanical locks and electronic locks are commonly used to control access to real estate properties. Some electronic locks, such as lockboxes, are capable of providing access for predetermined time periods. Certain electronic locks are also capable of control access to real estate properties based on one dimensional (1-D) barcodes and two dimensional (2-D) barcodes (also known as QR codes). As used herein, QR codes and three dimensional barcodes are also referred to as barcodes. Three dimensional (3-D) barcodes include a color dimension. The barcodes encode access data, such as access codes and allowed access time frame, and are scanned by the electronic locks. The electronic locks then authorize access to the real estate property, to which they are attached to, if the access data is authenticated.
The conventional real estate access control devices are not operatively coupled to real estate property showing appointment management system. A property showing appointment management system allows users (such as listing agents, showing agents, sellers, buyers, and others) to manage listings, managing listing agent profiles, manage showing agent profiles, schedule showing appointments, management showing appointments, communicate with others regarding real estate listings, collect and forward showing feedback, etc. The showing appointment management system can correctly authenticate accesses to properties without the risk of the access being compromised. Furthermore, the showing appointment management system maintains the up-to-date real estate data and assures the integrity of the data. Accordingly, there is a need for a system and method for control access to a real estate property via an electronic device attached to the property and the showing appointment management system.
Doorbells are widely used signaling devices for alerting persons inside real estate properties about the presence of visitors. A doorbell camera device (also referred to herein as a doorbell cam device) performs the functions of a conventional doorbell, and further incorporates a camera for providing video monitoring and surveillance capabilities. However, the conventional doorbell cam devices have never been operatively coupled to a showing appointment management system for managing showings and controlling access to the real estate property based on showing appointments. Therefore, there is a need for a new electronic device that reads showing data encoded in barcodes, communicates with the showing appointment management system to authenticate the showing data, and instructs an electronic lock to unlock itself after the showing data is authenticated.

Electronic device for providing access to properties


An envelope comprising a sheet of paper or the like which is folded along one foldine and then folded along a second foldline perpendicular to the first line to provide an envelope with an address viewable through a window but wherein an insert in the envelope cannot move to and obscure the view of the address through the window. One embodiment includes a return envelope made up of a portion of the aforesaid sheet and a second sheet which overlies said portion of the first sheet. Another embodiment provides a mailer without a viewing window and which is formed from a single ply foldable about orthogonally related foldlines and heat sealable along its edges to form a four-ply mailer.

The present invention pertains to mailers and particularly to mailers of a type readily enabling computer generated message and address information to be printed on a single paper ply which can be folded to form a self-contained multi-ply mailer. The mailer may have either a die-cut window for viewing the address information through the window when the paper ply is folded or be configured so that, when folded, address information is positioned for view without use of a die-cut window.
It is now quite common for mailers to be manufactured in automatic equipment, including means for so-called variable printing of names, addresses and other information under computer control. Many of these mailers, essentially envelopes, have a window for viewing the outgoing address which has been printed on an underlying panel in an area designed to lie within the confines of the window. Mailers are also designed to have inserts included therein, but inserts have created problems, for example, by moving into the address area and obscuring the view of the address information through the window. However, many customers prefer the use of die-cut windows for their mailings. Consequently, one of the problems associated with mailers using die-cut windows is to so locate the insert in the mailer such that the insert may not be physically able to obscure the viewing of the address information through the die-cut window.
From the standpoint of customer preference, as well as ease of printing computer-generated variable information on the mailer, the die-cut window is oftentimes not desirable. For example, a customer's computer printout program or data entry requirements may not conform to the placement of the die cut window on the mailer. Many customers require variable return addresses and these requirements often require two die-cut windows which, again, may not meet the printout or data entry requirements of the customer. Two die-cut windows also reduces available space on the mailer for substantive messages and the like. Also, certain printers may not accommodate forms with die-cut patched windows. Consequently, there is also a need for a single-ply mailer on which computer-generated variable information may be printed such that the ply, when folded to form the mailer, may display address information. It is also desirable in such mailer to conceal the computer-generated information, i.e., the substantive message part, within the mailer. This type of mailer should also be capable of receiving an insert.


A three dimensional printing system, the system including: a printhead; and a removable tray comprising a reservoir, the tray located in a print bed of the three dimensional printing system such that liquid purged from the printhead is deposited in the reservoir, wherein prior to the system purging liquid from the printhead, the system confirms that the tray is in place using a sensor.

This disclosure relates to removing liquid from a printhead. The method may be applied to a printbar comprising a plurality of printheads.
Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements. The figures are not necessarily to scale, and the size of some parts may be exaggerated to more clearly illustrate the example shown. Moreover, the drawings provide examples and/or implementations consistent with the description; however, the description is not limited to the examples and/or implementations provided in the drawings.

Hewlett-Packard Development Company, L.P.


A silver halide color photographic material composed of a support having thereon at least one light-sensitive silver halide emulsion layer, at least one layer thereof containing a yellow coupler represented by formula (I), a sparingly water-soluble epoxy compound represented by formula (II) and a water-insoluble but organic solvent-soluble homopolymer or copolymer: ##STR1## wherein R.sub.11 represents an N-arylcarbamoyl group; and Z.sub.11 represents a group capable of being released by a reaction with the oxidation product of an aromatic primary amine color developing agent; and ##STR2## wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4, which may be the same or different, each represents hydrogen, an aliphatic group, an aromatic group, an aliphatic oxycarbonyl group, an aromatic oxycarbonyl group or a carbamoyl group; provided that at least one of R.sub.1, R.sub.2, R.sub.3 and R.sub.4 represents a group other than hydrogen; R.sub.1, R.sub.2, R.sub.3 and R.sub.4 contain a total of 8 to 60 carbon atoms; and R.sub.1 and R.sub.2, or R.sub.1 and R.sub.3 may be linked to form a 5-membered to 7-membered ring. Because of the combination of the particular yellow coupler, epoxy resin and polymer, the storage stability of the yellow image formed in the material is excellent.

When a silver halide photographic material is exposed and then color developed, a color image is formed by the reaction of an aromatic primary amine developing agent as oxidized with the silver halide and a dye-forming coupler.
In color image formation, a subtractive color process is often used, in which complementary yellow, magenta and cyan color images are formed for reproduction of blue, green and red colors, respectively.
As yellow couplers, phenoxy group-releasable compounds are disclosed in U.S. Pat. Nos. 3,408,194 and 3,933,501; imido group-releasable compounds in U.S. Pat. Nos. 4,022,620, 4,057,432, 4,269,936 and 4,404,274; and heterocyclic group-releasable compounds in U.S. Pat. Nos. 4,046,575 and 4,326,024. Using these couplers, increases in coloring rate and fastness of color images formed are still desired.
In order to improve the fastness of the color images formed from these yellow couplers, U.S. Pat. No. 4,268,593 has proposed hindered amine compounds.
However, as compared with remarkable progress in the improvement of the fastness of magenta color images and cyan color images, the fastness of yellow color images is insufficient, and still remains at a low level. Accordingly, the improvement of the fastness of cyan color images is strongly desired in this technical field.
In color photographs, it is desired that all of the yellow, magenta and cyan color images be uniformly fast to light, heat and wet heat, and that the three colors be at the same level. The present inventors have earnestly sought compounds for improving the fastness of color images formed from yellow couplers.
The epoxy compounds described in U.S. Pat. No. 4,239,851 are known to improve the fastness of cyan color images against heat and wet heat; and the epoxy compounds described in U.S. Pat. No. 4,540,657 are known to reduce the yellow stain which would result from decomposition of magenta couplers. The latter U.S. Patent further mentions that the color images from aryloxy group-releasable yellow couplers could have improved fastness to light and heat, but this effect remains insufficient. JP-A-62-75450 (the term "JP-A" as used herein means an "unexamined published Japanese patent application") discloses cyclic ether compounds for reducing stains formed by processing with particular stable processing solutions. The present inventors have found that these compounds are effective for improving the fastness of the yellow color images, in particular in the dark under humid conditions, but the improvement in antifading properties in the light remained insufficient.
In the technical field of dispersing photographic oil-soluble compounds, it is known to disperse the compounds in oil-soluble homopolymers or copolymers, for example, as described in U.S. Pat. Nos. 3,619,195, 4,201,589 and 4,120,725.
The present inventors have now found that by incorporating a yellow coupler in a photographic material together with a water-insoluble but organic solvent-soluble polymer and an epoxy compound, not only the antifading properties of the image under wet heat is improved, but also the antifading properties thereof in light is surprisingly improved.

Silver halide color photographic material containing sparingly water soluble epoxy compound and organic soluble polymer


An extrusion blow molding apparatus for making hollow plastic articles includes a machine frame with an extruder horizontally received in the machine frame and having a nozzle head for vertically extruding a parison at one end face of the machine frame. A pair of split blow molds is disposed at this end face of the machine frame bilaterally underneath the nozzle head, with each blow mold cooperating with a blow mandrel secured to the machine frame above the blow mold. The extruder together with its drive and supply lines and at least one of the blow mandrels are detachably received in the machine frame so as to allow a positional exchange therebetween for allowing blow molding of round plastic articles as well as flat plastic articles.

The present invention refers to an extrusion blow molding apparatus for making hollow plastic articles.
An extrusion blow molding apparatus is known of the type having a machine frame which receives a horizontal extruder for vertically extruding a parison via its nozzle head at one end face of the machine frame. A pair of split blow molds is arranged symmetrically at the end face below the nozzle head, with each of the blow molds including a closing unit, a drive unit for horizontally sliding the blow mold underneath the nozzle head for receiving an extruded parison, and a blow mandrel secured to the machine frame above the blow mold.
An extrusion blow molding machine of this type is suitable for making hollow plastic articles of rotationally symmetrical cross section such as e.g. round bottles. Both blow molds are identical final blow molds which are moved horizontally by their respective drive unit from their initial position underneath the associated blow mandrel to a position underneath the nozzle head for seizing the parison being extruded by the nozzle head of the extruder. The parison is then blown to the finished hollow article by the respective blow mandrel after returning the respective blow mold into its initial position, with the finished hollow article being ejected after a suitable cooling period.
Such an extrusion blow molding apparatus is, however, not suitable for producing flat bottles since the construction lacks structural elements for transferring a semi-finished article from an intermediate blow mold to the final blow mold.
The European publication EP-PS 0 256 062 discloses an extrusion blow molding apparatus which includes two blow molds of different configuration for making flat bottles. One of the blow molds is an intermediate blow mold for making a semi-finished article of rotationally symmetrical cross section and the other blow mold represents a final blow mold by which this semi-finished article is transformed to a flat bottle. In this manner, flat bottles can be made through a particular material-saving process and with nearly even wall thickness at least over a major part of its height. The European application EP-PS 0 256 062 is, however, silent about the structure and design of the extrusion blow molding apparatus.
The production of hollow plastic articles of rotationally symmetrical cross section and hollow plastic articles of a cross section deviating therefrom necessitates the availability and operation of a separate extrusion blow molding apparatus for each type of hollow article. Depending on the order situation for both types of hollow articles, long stop periods for one or the other blow molding apparatus can be experienced and is unavoidable.

Extrusion blow molding apparatus for making hollow plastic articles


A silicon semiconductor substrate which realizes a defect-free region of void type crystals to a greater depth and allows the duration of production to be decreased and a method for the production thereof are provided. A silicon semiconductor substrate derived from a silicon single crystal grown by the Czochralski method or the magnetic field-applied Czochralski method, which is obtainable by using a silicon semiconductor substrate satisfying the relational expression, 0.2xe2x89xa7V/S/R, providing V denotes the volume of void type defects, S denotes the surface area thereof, and R denotes the radius of spherical defects presumed to have the same volume as the void defects having the volume of V, and heat treating this substrate at a temperature exceeding 1150xc2x0 C.

1. Field of the Invention
This invention relates to a silicon semiconductor substrate and a method for the production thereof. More particularly, the invention relates to a silicon semiconductor substrate which originates in a silicon semiconductor substrate so shaped as to permit easy extinction of void type defects by a heat treatment with a view to obtaining a defect-free region in a void type product and which, in consequence of a subsequent heat treatment, forms a deep defect-free surface layer, excels in device characteristics, and enjoys a satisfactory gettering property and to a method for the production thereof.
2. The Prior Art
Heretofore, as regards the improvement of the defect-freeness of the surface layer of the semiconductor substrate, the technique of heat-treating a given semiconductor substrate in an atmosphere of hydrogen gas at a temperature of 1200xc2x0 C. for a duration of not less than one hour thereby inducing expansion of a defect-free layer devoid of oxygen precipitate defects to a depth of 10 xcexcm from the surface layer has been reported (JP-A-06-252,154). This technique has been known to effect the extinction of void type defects (i.e. xe2x80x9cempty holexe2x80x9d type defects) to a depth of 1 to 3 xcexcm. Recently, the technique of effecting the extinction of the void type defects to a deeper region from the surface layer by decreasing the void type defects in size at a high density in consequence of the addition of nitrogen has been reported (JP-A-11-135,511 and JP-A-2000-256,092). In the latter invention, it is reported that the change in form of void type defects attracted interest and the addition of nitrogen in a pertinent shape of the defects proved effective.
The prior art mentioned above has barely unveiled the effect of the addition of nitrogen on the change of form manifested in the void type defects. Regarding the heat treatment which is performed for the purpose of effecting extinction of the void type defects, it has not imposed any limitation on the effective nitrogen concentration, the oxygen concentration, and the cooling rate to be used while the silicon single crystal being pulled passes through a temperature zone of 1100xc2x0 C. (hereinafter referred to simply as xe2x80x9ccooling ratexe2x80x9d). Specifically, in the void type defects, the voids which are point defects are diffused through the surface of the void type defects during the extinction thereof by the heat treatment. The diffusion in this case is proportional to the surface area forming the peripheral parts of the void type defects. The mere mention of the effect in the change of form does not deserve to be deemed as imposing a necessary limitation on the extinction of void type defects.
In fact, the heat treatment contemplated by the prior art induces extinction of the defects barely to the extent of recording a residual ratio on the order of percent at a depth of 0.5 xcexcm from the surface layer. It has not imposed on the void type defects a limitation enough for effecting extinction of the void type defects to such a density that the manufacture of a device under production conditions excelling in commercial productivity will not be adversely affected.
Owing to the current demand to produce silicon single crystals in increased diameters, the void type defects possibly gain unduly in growth, depending on the relevant production conditions. In the light of this fact, the prior art is suspected of manifesting its effect only insufficiently unless the addition of nitrogen is made in an adequate amount. From the viewpoint of permitting manufacture of a commercially useful silicon semiconductor substrate enjoying extinction of void type defects throughout to a deep region from the surface layer, therefore, the prior art is at a disadvantage in lacking limitations of conditions.
It is, therefore, an object of this invention to provide a novel silicon semiconductor substrate and a method for the production thereof in view of such drawbacks of the prior art as mentioned above.
To be specific, this invention is capable of effecting extinction of void type defects to a deep region from the surface layer, the feature which has not been attained by the prior art. For a fixed temperature of the heat treatment, this invention is capable of attaining the extinction of the void type defects to a region of a greater depth than the prior art.
This invention is directed to providing a method of production which enables a silicon semiconductor substrate possessing a defect-free layer of a required depth to be manufactured by performing a heat treatment for a shorter duration than the prior art in forming the defect-free layer in a fixed depth. The objects mentioned above are accomplished by the following items (1)xcx9c(10).
(1) A silicon semiconductor substrate derived from a silicon single crystal grown by the Czochralski method or the magnetic field-applied Czochralski method, characterised by satisfying the relation, 0.2xe2x89xa7V/S/R, providing V denotes the volume of void type defects, S the surface area thereof, and R the radius of spherical defects presumed to have the same volume as the void type defects having the volume of V.
(2) A silicon semiconductor substrate set forth in item (1) above, which contains nitrogen at a concentration of not less than 1xc3x971014 atoms/cm3 and not more than 1xc3x971016 atoms/cm3.
(3) A silicon semiconductor substrate set forth in item (1) above, wherein the void type defects in the silicon semiconductor substrate having an oxygen concentration of not more than 9.5xc3x971017 atoms/cm3 and a nitrogen concentration of not less than 5xc3x971014 atoms/cm3 and not more than 1xc3x971016 atoms/cm3, when presumed to have spherical volumes, have a radius R satisfying Rxe2x89xa630 nm.
(4) A silicon semiconductor substrate set forth in item (1) above, wherein the void type defects in the silicon semiconductor substrate having an oxygen concentration of not more than 8.5xc3x971017 atoms/cm3 and a nitrogen concentration of not less than 5xc3x971014 atoms/cm3 and not more than 1xc3x971016 atoms/cm3, when presumed to have spherical volumes, have a radius R satisfying Rxe2x89xa675 nm.
(5) A method for the production of a silicon semiconductor substrate, characterised by causing a silicon semiconductor substrate set forth in item (1) above as derived from a silicon single crystal grown by the Czochralski method or the magnetic field-applied Czochralski method using a cooling rate of not less than 1xc2x0 C./min while the silicon single crystal being pulled passes through a temperature zone of 1100xc2x0 C. to be heat-treated in a non-oxidising atmosphere at a temperature of not less than 1150xc2x0 C. for not less than one hour at least.
(6) A method for the production of a silicon semiconductor substrate, characterised by causing a silicon semiconductor substrate set forth in item (2) above as derived from a silicon single crystal grown by the Czochralski method or the magnetic field-applied Czochralski method using molten silicon containing nitrogen at a concentration of not less than 1xc3x971017 atoms/cm3 and not more than 1.5xc3x971019 atoms/cm3 and using a cooling rate of not less than 1xc2x0 C./min while the silicon single crystal being pulled passes through a temperature zone of 1100xc2x0 C. to be heat-treated in a non-oxidising atmosphere at a temperature of not less than 1150xc2x0 C. for not less than one hour at least.
(7) A method for the production of a silicon semiconductor substrate, characterised by causing a silicon semiconductor substrate set forth in item (3) above as derived from a silicon single crystal grown by the Czochralski method or the magnetic field-applied Czochralski method using molten silicon containing nitrogen at a concentration of not less than 5xc3x971017 atoms/cm3 and not more than 1.5xc3x971019 atoms/cm3 and using a cooling rate of not less than 5xc2x0 C./min while the silicon single crystal being pulled passes through a temperature zone of 1100xc2x0 C. to be heat-treated in a non-oxidising atmosphere at a temperature of not less than 1150xc2x0 C. for not less than one hour at least.
(8) A method for the production of a silicon semiconductor substrate, characterised by causing a silicon semiconductor substrate set forth in item (4) above as derived from a silicon single crystal grown by the Czochralski method or the magnetic field-applied Czochralski method using molten silicon containing nitrogen at a concentration of not less than 1xc3x97108 atoms/cm3 and not more than 1.5xc3x971019 atoms/cm3 and using a cooling rate of not less than 1xc2x0 C./min and less than 5xc2x0 C./min while the silicon single crystal being pulled passes through a temperature zone of 1100xc2x0 C. to be heat-treated in a non-oxidising atmosphere at a temperature of not less than 1150xc2x0 C. for not less than one hour at least.
(9) A method for the production of a silicon semiconductor substrate, characterised by heat-treating a silicon semiconductor substrate set forth in item (3) above in a non-oxidising atmosphere at a temperature of not less than 1200xc2x0 C. thereby causing the semiconductor substrate to acquire an oxygen concentration of not more than 6xc3x971016 atoms/cm3 at a depth of 1 xcexcm from the surface at the centre thereof, a locally concentrated part originating in a nitrogen segregation exhibiting a concentration of not less than twice as high as the average signal strength at the centre of the silicon substrate depth in the determination of nitrogen concentration by the method of secondary ion mass analysis (SIMS), a surface defect-free layer of a depth of not less than 5 xcexcm at least and less than 12 xcexcm from the surface, and an oxygen precipitate density of not less than 1xc3x97109 pieces/cm3 at the centre of depth of the central part of the silicon substrate.
(10) A method for the production of a silicon semiconductor substrate, characterised by heat-treating a silicon semiconductor substrate set forth in item (4) above in a non-oxidising atmosphere at a temperature of not less than 1200xc2x0 C. thereby causing the semiconductor substrate to acquire an oxygen concentration of not more than 5xc3x971016 atoms/cm3 at a depth of 1 xcexcm from the surface at the centre thereof, a locally concentrated part originating in a nitrogen segregation exhibiting a concentration of not less than twice as high as the average signal strength at the centre of the silicon substrate depth in the determination of nitrogen concentration by the method of secondary ion mass analysis (SIMS), a surface defect-free layer of a depth of not less than 5 xcexcm at least and less than 12 xcexcm from the surface, and an oxygen precipitate density of not less than 5xc3x97108 pieces/cm3 at the centre of depth of the central part of the silicon substrate.
The silicon semiconductor substrate according to this invention is obtained by slicing a segment of a prescribed thickness from a silicon single crystal grown by the Czochralski method (hereinafter referred to as xe2x80x9cCZ methodxe2x80x9d) or the magnetic field-applied Czochralski method (hereinafter referred to as xe2x80x9cmagnetic field-applied CZ methodxe2x80x9d).
To be specific, the CZ method comprises growing a silicon single crystal bar of a required diameter by causing a seed crystal to contact the melt of a polycrystalline silicon raw material accommodated in a quartz crucible and slowly pulling it upward as kept in rotation meanwhile. The crystal while being pulled can be doped with nitrogen by having a nitride placed in advance in the quartz crucible or injecting the nitride into the molten silicon or having the ambient gas encircling the site of crystal growth contain nitrogen from the beginning. In this case, the amount of the dopant incorporated into the crystal can be controlled by adjusting the amount of the nitride, the concentration of the nitrogen gas, or the duration of the injection. The magnetic field-applied CZ method is identical with the CZ method, except it performs the operation of pulling a crystal bar while continuing application of a magnetic field to the interior of the quartz crucible. In this manner, the nitrogen concentration can be easily controlled in the range of 1xc3x971017xcx9c1.5xc3x971019 atoms/cm3 in the silicon melt or in the range of 1xc3x971014xcx9c1xc3x971016 atoms/cm3 in the silicon single crystal.
Further, this invention prefers the oxygen concentration in the silicon single crystal bar to be controlled in the range of 6xc3x971017xcx9c1xc3x971018 atoms/cm3 during the growth of the single crystal bar doped with nitrogen by the CZ method or the magnetic field-applied CZ method.
During the growth of the silicon single crystal bar, the necessity for decreasing the oxygen concentration in this crystal bar to a level in the range mentioned above may be fulfilled by any of the methods heretofore adopted popularly. The adjustment of the oxygen concentration in the range mentioned above can be easily attained by such means as, for example, decreasing the rotational frequency of the crucible, increasing the flow rate of the gas to be introduced, lowering the atmospheric pressure, and adjusting the temperature distribution and the convection in the molten silicon.
Further, this invention, while growing the silicon single crystal bar doped with nitrogen by the CZ method or the magnetic field-applied CZ method, prefers the cooling rate of the growing crystal to be controlled in the range of 1xcx9c15xc2x0 C./min. Actually, the realisation of these conditions for the production of crystal may be attained, for example, by a method of adjusting the pulling speed of the crystal thereby increasing or decreasing the speed of the growth of the crystal. It may be otherwise attained by installing within the chamber of an apparatus for the production of a silicon single crystal by the CZ method or the magnetic field-applied CZ method a device which is capable of cooling the crystal at an arbitrary cooling rate. As the cooling device of this nature, it suffices to use a device which can cool a given crystal by blowing a cooling gas or adopt a method for disposing at a fixed position on the surface of the molten silicon a water-cooling ring adapted to encircle the crystal in growth. In this case, by using the cooling method mentioned above and adjusting the speed of pulling the crystal in growth, it is made possible to confine the cooling rate within the range mentioned above.
Thus, in the CZ method or the magnetic field-applied CZ method, the silicon single crystal bar doped with nitrogen in a required concentration, made to contain oxygen in a required concentration, and grown at a required cooling rate can be obtained. This silicon single crystal bar is then sliced with such a cutting device as the inner peripheral blade slicer or the wire saw and subjected to the steps of chamfering, lapping, etching, and grinding to manufacture a silicon single crystal wafer. Naturally, these steps are enumerated here for the exclusive purpose of illustration. Various other steps such as washing are also conceivable. The sequence of these steps may be altered or part of the steps may be omitted properly to suit the purpose of use of the finished product.
The silicon single crystal wafer which is obtained as described above permits manufacture of a silicon semiconductor substrate which satisfies the relation, 0.2xe2x89xa7V/S/R, providing V denotes the volume of void type defects (i.e. xe2x80x9cempty holexe2x80x9d type defectsxe2x80x9d), S the surface area thereof, and R the radius of spherical defects presumed to have the same volume as the void type defects having the volume of V. Subsequently by subjecting the silicon semiconductor substrate to a gettering heat treatment and/or a heat treatment required for the production of a device, it is made possible to decrease the void type defects in the surface layer with excellent operational efficiency to such an extent as to preclude occurrence of defects in the produced device.
This invention defines the volume of the void type defects. The volume, V, and the surface area, S, were the numerical values obtained in the relevant experiment by tilting a sample of TEM and three-dimensionally measuring the void type defects in shape. The radius, R, was found by calculating the relational expression, V=4ΠR3/3, wherein V denotes the volume found by the visual observation of TEM.
The silicon semiconductor substrate contemplated by this invention has the nitrogen concentration thereof fall in the range of 1xc3x971014 atoms/cm3xcx9c1xc3x971016 atoms/cm3 as determined by the analysis of nitrogen in accordance with the method of secondary ion mass analysis (SIMS). Then, the void type defects in the silicon single crystal, as specifically described herein below, have the shape thereof changed from an octahedron to a plate and further from a plate and/or a plate-like shape of a large ratio of change of shape to an oxygen precipitate (wholly OSF region), depending on the concentration of nitrogen increased by addition and the cooling rate used while the silicon single crystal being pulled passes through a temperature region of 1100xc2x0 C. In this region, since the void type defects of a shape other than the octahedron have a large surface area as compared with the conventional octahedral void type defects, the heat treatment performed subsequently tends to promote diffusion of voids which are point defects and give rise to a surface defect-free layer. As regards the range for the ratio of volume/surface area of the void type defects of the shape of a plate and further the shape of a plate and/or a bar which have a larger surface area than the octahedral void type defects, it suffices to control the void type defects of such a shape as satisfies the relational expression, 0.2xe2x89xa7V/S/R, by the state thereof prior to the heat treatment. When this relational expression is satisfied, the subsequent heat treatment will facilitate the extinction of the void type defects. Then, the amount of added nitrogen necessary for satisfying this condition is required to satisfy at least the condition of this invention, i.e. the range of 1xc3x971014 atoms/cm3xcx9c1xc3x971016 atoms/cm3.
The silicon semiconductor substrate whose void type defects have been rendered more extinctive by the heat treatment is preferred to have an oxygen concentration of not more than 9.5xc3x971017 atoms/cm3 and a nitrogen concentration in the range of 5xc3x971014xcx9c1xc3x971016 atoms/cm3 when the cooling rate is not less than 5xc2x0 C./min before it is heat-treated in a non-oxidising atmosphere such as, for example, an atmosphere of one member or a mixture of two or more members selected from among such gases as hydrogen, nitrogen, argon, and helium. When the cooling rate is not less than 1xc2x0 C./min and less than 5xc2x0 C./min, the oxygen concentration is preferred to be not more than 8.5xc3x971017 atoms/cm3 and a nitrogen concentration to be in the range of 1xc3x971013xcx9c1xc3x971016 atoms/cm3. Then, when the void type defects in the silicon semiconductor substrate whose nitrogen concentration has been controlled as described above have been made to assume spherical volumes, the radius R of such spherical volumes is preferred to satisfy the condition, Rxe2x89xa630 nm, when the cooling rate is not less than 5xc2x0 C./min and the condition, Rxe2x89xa675 nm, when the cooling rate is not less than 1xc2x0 C./min and less than 5xc2x0 C.
Here, the case of using a cooling rate of not less than 1xc2x0 C./min and less than 5xc2x0 C./min and the case of using a cooling rate of not less than 5xc2x0 C./min are discriminated because the nitrogen concentration that induces a change in form of the void type defects from an octahedron through a shape of plate and a shape of bar varies across a cooling rate of about 5xc2x0 C./min as the boundary and the former cooling rate tends to increase the surface area to a greater extent than the latter cooling rate for a fixed amount of added nitrogen and to bring a greater effect in attaining extinction of the void type defects by the subsequent heat treatment even when such void type defects have larger dimensions. The radius R which this invention contemplates in presuming the void type defects to possess spherical volumes, therefore, is allowed to have a larger numerical value in the former case of using a slower cooling rate.
The reason for discriminating the ranges of oxygen concentration by the magnitude of cooling rate is that the ease with which the inner walls of the void type defects grow a silicon oxide film increases in accordance as the cooling rate is decreased and, for the sake of the extinction of the void type defects, the inner wall oxide film must be wholly diffused till extinction as the first step. When the cooling rate is slow, therefore, it becomes necessary to decrease the inner wall oxide film in thickness. To be specific, the oxygen concentration in the silicon semiconductor substrate prior to the heat treatment which is performed for the sake of the extinction of the void type defects must be controlled to a lower level than when the cooling rate is fast. Actually, the oxygen concentration of the silicon semiconductor substrate prior to the heat treatment is preferred to be limited within the range contemplated by this invention as will be specifically described herein below.
Of the silicon semiconductor substrate derived from the silicon single crystal grown by the CZ method or the magnetic field-applied CZ method using a cooling rate exceeding 1xc2x0 C./min, preferably falling in the range of 1xcx9c15xc2x0 C./min, the silicon semiconductor substrate that satisfies the relation, 0.2xe2x89xa7V/S/R, before undergoing the heat treatment contemplated by this invention is heat-treated in the non-oxidising atmosphere mentioned above at a temperature exceeding 1150xc2x0 C., preferably falling in the range of 1150xcx9c1250xc2x0 C., for a duration exceeding one hour, preferably falling in the range of 2xcx9c4 hours when the maximum final temperature is 1150xc2x0 C. or in the range of 1xcx9c2 hours when the maximum final temperature is in the range of 1200xcx9c1250xc2x0 C. to produce a silicon semiconductor substrate which possesses a defect-free layer containing no void type defect in the surface layer and excelling in yield of device.
For the purpose of satisfying the condition, 0.2xe2x89xa7V/S/R, for the shape allowing easy extinction of the void type defects thereby obtaining a silicon semiconductor substrate which has attained extinction of the void type defects in the surface layer of the silicon semiconductor substrate as aimed at by this invention, the silicon semiconductor substrate prior to the heat treatment is only required to contain nitrogen in a concentration in the range of 1xc3x971014xcx9c1xc3x971014 atoms/cm3. For the purpose of enabling the silicon semiconductor substrate to incorporate therein nitrogen in the concentration mentioned above, it suffices to employ the CZ method or the magnetic field-applied CZ method in pulling molten silicon on the condition that the molten silicon contains nitrogen at a concentration in the range of 2xc3x971017xcx9c1.5xc3x971019 atoms/cm3 during the course of a pulling operation. The cooling rate used while the silicon single crystal being pulled passes through a temperature zone of 1100xc2x0 C. is only required to exceed 1xc2x0 C./min. More preferably by defining the nitrogen concentration and the cooling rate respectively, the extinction of the void type defects from the surface of the silicon substrate subsequent to the heat treatment which is aimed at the extinction of the void type defects can be secured to a deeper region. When the cooling rate is not less than 1xc2x0 C./min and less than 5xc2x0 C./min, the nitrogen concentration in the silicon semiconductor substrate is preferred to be in the range of 1xc3x971015xcx9c1xc3x971016 atoms/cm3 and that in the molten silicon in the process of being pulled is preferred to be in the range of 1xc3x971018xc3x971.5xc3x971019 atoms/cm3 for the sake of the incorporation of nitrogen at the concentration mentioned above. When the cooling rate is not less than 5xc2x0 C./min, the nitrogen concentration in the silicon semiconductor substrate is preferred to be in the range of 5xc3x971014xcx9c1xc3x971016 atoms/cm3 and that in the molten silicon in the process of being pulled is preferred to be in the range of 2xc3x971017xcx9c1xc3x971019 atoms/cm3 for the sake of the incorporation of nitrogen at the concentration mentioned above. When the silicon semiconductor substrate derived from the silicon single crystal grown under the conditions mentioned above is heat-treated in the non-oxidising atmosphere mentioned above at a temperature exceeding 1150xc2x0 C., preferably falling in the range of 1150xcx9c1250xc2x0 C. for a period exceeding one hour, preferably falling in the range of 2xcx9c4 hours when the maximum final temperature is 1150xc2x0 C. or in the range of 1xcx9c2 hours when the maximum final temperature is in the range of 1200xcx9c1250xc2x0 C., it produces a semiconductor substrate containing no void type defect in the surface layer and excelling in device yield.
The inner wall oxide film of the void type defects needs control as described above. When the cooling rate during the course of a pulling operation is not less than 1xc2x0 C./min and less than 5xc2x0 C./min, the oxygen concentration prior to the heat treatment is preferred to be not more than 8.5xc3x971017 atoms/cm3. When the cooling rate is not less than 5xc2x0 C./min, the oxygen concentration prior to the heat treatment is preferred to be not more than 9.5xc3x971017 atoms/cm3.
According to this invention, when the silicon semiconductor substrate having the R satisfy the formula Rxe2x89xa630 nm is heat-treated in the non-oxidising atmosphere mentioned above at a temperature exceeding 1200xc2x0 C., preferably falling in the range of 1200xcx9c1250xc2x0 C. to produce a silicon semiconductor substrate having an oxygen concentration of not more than 6xc3x971016 atoms/cm3 at a depth of 1 xcexcm from the surface at the centre of the semiconductor substrate and a locally concentrated part originating in a nitrogen segregation exhibiting a concentration of not less than twice as high as the average signal strength at the centre of the silicon substrate depth in the determination of nitrogen concentration by the method of secondary ion mass analysis (SIMS), the produced silicon semiconductor substrate possesses a surface defect-free layer of a depth of not less than 5 xcexcm at least and less than 12 xcexcm from the surface, enjoys a satisfactory device yield such that the oxygen precipitate density is not less than 1xc3x97109 pieces/cm3 at the centre of depth in the central part of the silicon substrate, and excels in the gettering property.
Further, according to this invention, when the silicon semiconductor substrate having the R satisfy the formula Rxe2x89xa675 nm is heat-treated in the non-oxidising atmosphere mentioned above at a temperature exceeding 1200xc2x0 C., preferably falling in the range of 1200xcx9c1250xc2x0 C. to produce a silicon semiconductor substrate having an oxygen concentration of not more than 5xc3x971016 atoms/cm3 at a depth of 1 xcexcm from the surface at the centre of the semiconductor substrate and a locally concentrated part originating in a nitrogen segregation exhibiting a concentration of not less than twice as high as the average signal strength at the centre of the silicon substrate depth in the determination of nitrogen concentration by the method of secondary ion mass analysis (SIMS), the produced silicon semiconductor substrate possesses a surface defect-free layer of a depth of not less than 5 xcexcm at least and less than 12 xcexcm from the surface, enjoys a satisfactory device yield such that the oxygen precipitate density is not less than 5xc3x97108 pieces/cm3 at the centre of depth in the central part of the silicon substrate, and excels in the gettering property.

Silicon semiconductor substrate and method for production thereof

Wacker Siltronic Gesellschaft Fxc3xcr Halbleiter Materialien AG


Zn-Mg alloy is plated by vapor deposition on the surface of metals. Since Zn and Mg are vapor-deposited as a vapor mixture of an optional ratio on the surface of metals, plated layers of excellent corrosion resistance, peeling resistance of coating film, formability, etc. can be formed. There is disclosed a method of forming uniform vapor mixtures of Zn and Mg, and vapor-depositing them on the surface of metals as the method forming the vapor-deposited layers.

1. Field of the Invention
The present invention concerns metal materials of excellent corrosion resistance plated with a Zn-Mg alloy by vapor deposition, which are extremely useful as outer plates for vehicles or home electrical or electronic products, as well as various building materials. They include those materials that are used with or without coating, as well as include those materials used with or without fabrication such as in press molding.
Metal substrate materials to be plated in accordance with the present invention include Fe or Fe-based alloys, as well as non-iron metals such as Cu, Al and Ti or alloys thereof. They may be in any of shapes such as plates, corrugated, tubular or rod-like materials, as well as profiled materials H- or I-cross sectioned rods, with no particular restrictions. Although explanation is to be made hereinafter mainly for the most representative steel sheets, the technical scope of the present invention should not be construed only thereto.
2. Description of the Prior Art
Zn-plating has generally been employed as means for applying corrosion Resistant proof to steel sheets, etc. However, the demand for the improvement of the corrosion proofness of steel sheets, etc. has because increased, and Zn-plated steel sheets in the prior art can no more satisfy the requirement of users. It may be considered to improve the corrosion resistance by increasing the deposition amount of plating, but it brings about drawbacks such as powdering upon press molding, degradation upon spot welding and increased cost.
In view of the such a technical background, steel sheets plated with Zn-alloys such as Zn-Ni, Zn-Fe, Zn-Mn, Zn-Co, etc. utilizing the electroplating method have been developed, as well as steel sheets plated with multi-component Zn-Al alloys such as Zn-Al-Misch metal, Zn-Al-Si, Zn-Al-Mg, Zn-Al-Sn, etc. using the hot dip galvanizing method have also been developed.
However, for the Zn-alloy plated steel sheets obtained by the electroplating method, the following problems have been pointed out.

Zn-Mg alloy vapor deposition plated metals of high corrosion resistance, as well as method of producing them


When this image processing device forms an image on a sheet, an image data storage unit stores image data received by an image data reception unit. An image formation count unit counts the number of times the image of the stored image data is formed by an image output unit. An information addition unit adds additional information to the image data according to the counted number of times. The image output unit forms the image of the image data together with the additional information on the sheet.

1. Field of the Invention
The present invention generally relates to an image processing device, and more particularly, to an image processing device having a security function in a printing apparatus, such as a printer, a copying machine, or a facsimile, or in an input apparatus, such as a scanner, which stores obtained image data in the apparatus itself.
2. Description of the Related Art
Recently, recording media, such as a DRAM (Dynamic Random Access Memory) and a HDD (Hard Disk Drive) have become less costly; accordingly, it has become possible to store a large quantity of image data in an image processing device at a low cost. Thus, a storing (filing) function can be added to an apparatus which conventionally has only a function of printing on a sheet, or printing image data read from a subject document. Since an apparatus having the storing function is capable of storing image data that have been processed before, the apparatus can perform a reprocessing (i.e., outputting a same image data again) in a largely shortened operation time.
Whereas such apparatuses have become more convenient as above, there has occurred a security problem. Specifically, there has occurred a risk that a third person may illegally output the stored image data. Conventionally, a personal identification using a password has been introduced in an attempt to prevent such an illegal output.
By the way, though not aimed at preventing an illegal output of stored image, Japanese Laid-Open Patent Application No. 6-268791 describes a digital copying apparatus that can perform a normal copying process, and at the same time, can display image data on a monitor, for the purpose of tracking an illegal use of the apparatus. Additionally, Japanese Laid-Open Patent Application No. 7-212602 describes a copying apparatus having a security function which attempts to prevent an illegal use by converting image data into image data suitable for a reductive printing, and storing the image data. Thus, monitoring stored image data, or applying a predetermined process to image data upon storing the image data, is intended to enable a conjecture of the presence of an illegal use, or a conjecture of an illegal user.
However, regarding the above-mentioned conventional apparatuses, once the password for the personal identification is broken, it becomes difficult to conjecture whether or not there has been an illegal output, or who has output image data illegally. In addition, the digital copying apparatus and the copying apparatus having the security function described in Japanese Laid-Open Patent Application No. 6-268791 and Japanese Laid-Open Patent Application No. 7-212602, respectively, are aimed at preventing an illegal deed concerning a first output upon storing image data, and thus cannot deal with an illegal output of already stored image data (a second output onward). Further, those copying apparatuses are not contrived to facilitate a reprocessing using the stored image data.

Image processing device forming an image of stored image data together with additional information according to an image formation count


The present invention discloses an induction flush device connecting water supply and a toilet bowl. The induction flush device includes a tank, a fixing board, a flush valve set and a panel. The panel is mounted on a side of the tank. The flush valve set is mounted on the fixing board. The tank forms a first guiding element thereon, and the fixing board forms a second guiding element thereon for cooperating with the first guiding element, thereby the fixing board is movable relative to the tank. The flush valve set includes an anti-reverse valve, an electromagnetic valve, a flexible inlet pipe for connecting with the water supply, and a flexible outlet pipe for draining water to toilet bowl. The flush valve set is movable relative the tank with the fixing board for repairing or replacement.

1. Field of the Invention
The present invention relates to an induction flush device, and particularly to an induction flush device for flushing a toilet bowl.
2. Related Art
Induction flush devices are often used to automatically flush toilet bowls, such as urinals and squat pans.
In prior art, wall-embedded induction flush device normally has a tank embedded at a predetermined position on a wall, a chamber provided in the tank, and a flush valve set. An inlet pipe is connected with an end of the flush valve set for supplying water, and an outlet pipe is connected with another end of the flush valve set for draining water to flush the toilet bowl.
The flush valve set consists of an anti-reverse valve and an electromagnetic valve. The anti-reverse valve connects with the inlet pipe. The electromagnetic valve has an end connecting with the outlet pipe and electrically connecting with an external infrared induction source.
The external infrared induction source is arranged at a cover of a front side of the tank. The infrared induction source activates the electromagnetic valve after use, and then water flows through the outlet pipe to flush the water bowl.
Although the flush valve set automatically flush a toilet bowl, it has to be removed from the chamber of the tank when the flush device needs to be repaired. In order to reduce volume and manufacture cost, the chamber of the tank has dimension nearly fit for size of the flush valve set. In a whole, the flush device is troublesome to be repaired, even some components thereof cannot be repaired or replaced.


The present invention relates to a method and an apparatus for producing cell population of the same chronological age. Cells of a predetermined age are collected onto an array of surfaces. The collected cells are retained on the said surface during their continuous cultivation and kept from mixing with their descendants by means of flushing away their offspring. Sampling of surface from the array at desired time gives cell populations of desired cell age for examination, assay and other different uses.

1. Field of the Invention
The present invention relates to a method and apparatus that facilitates the collection of age-homogenous cell population and the maintenance of age synchrony in the collected cell population. More particularly, the invention is directed to a process and equipment for producing truly age-homogeneous cell population by obtaining an initial cell population in a very short period of time and maintaining the age homogeneity of this population during the subsequent aging process by constant removal of their offspring.
2. Description of Related Art
(1) The existing methods for cell synchronization.
Since early 1950s, various efforts have been made for obtaining xe2x80x9csynchronizedxe2x80x9d cell population. For comprehensive reviews, see examples by E. Zeuthen (Synchrony in Cell Division and Growth, Interscience Publishers, New York, 1964), C. E. Helmstetter (Meth. Enzymol., 1, 327-363, 1969), and W. Krek and J. A. DeCaprio (Meth. Enzymol., 254, 114-124, 1995). In general, methods developed for cell synchronization can be classified as selection synchronization and induction synchronization.
In selection synchronization, a difference in the physicochemical properties of the cells in different divisional stages is often used as a basis for xe2x80x9ccell cyclexe2x80x9d (reproduction cycle) stage-specific separation. The physicochemical properties being utilized can be intrinsic cell properties such as the cell size and the cell density or artificially afforded properties such as the labeled molecules incorporated into the biomass or labeled molecules attached to the cell surface.
In induction synchronization, cells at different developmental stages are stopped at or induced into a predetermined developmental stage. Upon a desired time, these cells are allowed to proceed into subsequent development at the same release time to start the synchronization. The most frequently used agents for stopping or inducing cell development are those that interfere or promote xe2x80x9ccell cyclexe2x80x9d (cell reproduction cycle).
A special cell synchronization device called xe2x80x9cbaby machinexe2x80x9d has been developed (C. E. Helmstetter and D. J. Cummings, Proc. Natl. Acad. Sci. USA, 50, 767-774, 1963; C. E. Helmstetter, New Biol., 3, 1089-1096, 1991; C. E. Helmstetter et al., J. Bacteriol., 174, 3445-3449, 1992). With this approach, baby cells released from the cells bound to a filter are collected and are allowed to grow together in further cultivation. It is hoped that the continuous cultivation of these baby cells should yield cell cycle synchrony for long time. But in reality, this expectation has never been realized, even when this method is used for synchronization of Escherichia coli and yeast (C. E. Helmstetter, New Biol., 3, 1089-1096, 1991; C. E. Helmstetter et al., J. Bacteriol., 174, 3445-3449, 1992).
A plate release technique has been used for synchronizing Caulobacter, an asymmetric bacterium that divides into a swarmer cell and a stalked cell (S. T. Degnen and A. Newton, J. Mol. Biol. 64, 671-680, 1972). Due to the adhesive property of the holdfast at the tip of the stalk, stalked cells attach to the surface such as the plate surface of the Petri dish and remain attached during their subsequent cell divisions. However, swarmer cells swim into the liquid phase once there are divided from the attached stalked cells because the motor activity of the polar flagellum on each swarmer cells. Thus, cell age synchronization of Caulobacter can be started simply by collecting swarmer cells released in a short period when they are divided from the adhered stalked cells. However, many studies have repeatedly shown that subsequent cultivation of these age-synchronous swarmer cells unavoidably leads to cell cycle asynchrony once the second cell cycle starts. This is because, while a stalked cell will divide soon after it finish the first cell cycle, a swarmer cell must grow into a stalked cell and then enters the next cell cycle. Thus, to achieve continuous cell cycle synchronization of Caulobacter, it is necessary to perform repeated density centrifugation to separate the two types of Caulobacter cells. This repeated centrifugation process is labor-intensive and time-consuming. For this reason, few studies on Caulobacter have extended into the second cell cycle of its life span.
Some methods have been developed for obtaining old cells of budding yeasts. One method is based on the size/density difference between the bigger mother cells and the smaller baby buds and requires successive repetition of rate-zonal sedimentation in sucrose density gradients to separate larger old cells from smaller young cells (N. K. Egilmez et al., J. Gerontol. Biol. Sci., 45, B9-B17, 1990). Another method depends on selectively labeling young cells with biotin and then obtains these biotin-labeled cells when they grow older through the binding between biotin and avidin, which is coated on magnetic beads (T. J. Smeal et al., Cell, 84, 633-642, 1996).
(2) The drawbacks of existing methods for cell synchronization.
It is well known that all existing methods of cell synchronization are inadequate for maintaining cell division synchrony for more than a few cell division cycles, whether the cells populations are prokaryotic unicellular microorganisms, eukaryotic unicellular microorganisms, or eukaryotic tissue cells of multicellular organisms (E. Zeuthen, Synchrony in Cell Division and Growth, lnterscience Publishers, New York, 1964; C. E. Helmstetter et al., J. Bacteriol., 174, 3445-3449, 1992). The underlying causes for such rapid deterioration of the synchrony in continuous culture of the initially synchronized cell population remains enigmatic.
A fundamental assumption made explicitly or inexplicitly for existing cell synchronization methods is that two cells formed from one cell are daughter cells of the same generation and of the same age (F. C. Neidhardt et al., Physiology of the Bacterial Cell: A Molecular Approach, Sinauer Associates, Inc., Sunderland, Mass., 1990; B. Alberts et al., Molecular Biology of the Cell, 3rd ed., Garland Publishing, Inc., New York, 1994). Because of this widely held but unproven assumption, it is generally believed that, once a cell population is obtained at or induced to the same cell division stage, it should automatically yield cells of the same division stage (often inappropriately called the cell age) during the subsequent cultivation.
However, this dogmatic view of cell life and cell synchronization is contradictory to the reality of many forms of cellular life and is also logically fallacious (S. V. Liu, Logical Biology, 2000, 5-16, 2000). A new model for cellular life proposes that the two cells formed from the division of one cell really belong to two successive generations and of different ages (S. V. Liu, Science in China, 42, 644-654, 1999). If the new model is correct, it means that the fundamental assumption made in most existing cell synchronization methods is invalid.
Collectively, the existing methods for cell synchronization often suffer one or more of the following drawbacks:
(a) The initial cell population used for starting cell synchronization often comprises cells of different ages. It has been widely believed that cells at the same divisional (reproduction) stages are of the same age. However, this assumption does not reflect all the reality and is logically invalid. For example, to say that all pre-divisional cells are of the same cell age is just like to say that all the pre-laboring mothers are of the same age. This statement is not true because even women of different ages can become pregnant at the same time and thus become xe2x80x9csynchronousxe2x80x9d in their reproduction stages.
(b) Cells belong to different generations are mixed in the continuous cultivation of the initially cell divisional stage- or cell age-synchronized cell population. The basic assumption of one mother cell divides into two daughter cells violates the fundamental principle of biological reproduction, which means a process for generation succession and genetic inheritance. Although final disproval of this erroneous assumption requires further scientific investigations, it is not difficult to point out the logical flaw of this argument and its incompatibility with the general principle of life. For example, no one would believe that a female human being would become just one of her offspring after she finishes the laboring. Thus, without separating the offspring from their parents, the continuous cultivation of the initial age-synchronous cell population will naturally lead to a mixing of two successive generations and thus age heterogeneity. To illustrate this point with a more familiar form of livexe2x80x94the human being, no one would believe that a human population consisting of the same age of different females will remain its age homogeneity if their newborns stays together with them.
(c) Induction synchronization methods developed today are capable of achieving only the cell division (reproduction) synchronization, not necessarily the cell age synchronization. Theoretically, all agents affecting the cell cycle (cell reproduction cycle) works on all cells regardless of their ages. It is thus possible to make cells of different chronological age to be stopped at or to be induced into the same reproductive (cell cycle) stage. For this reason, cell cycle-synchronized cell population is not necessarily cell age-synchronized.
(d) Tedious and unnatural procedures are used in age-specific cell synchronization methods. So far only a few methods can be used to obtain truly age-homogenous cell populations at the age older than one cell reproduction cycle and these methods are used for obtaining old yeast cells (N. K. Egilmez et al., J. Gerontol. Biol. Sci., 45, B9-B17, 1990; T. J. Smeal et al., Cell, 84, 633-642, 1996). However, these methods require tedious processes and specialized agents or equipments. For example, repetitive centrifugations are required for collecting old yeast cells and separating them from young budding cells in order to achieve long-term cultivation of the initial mother cells. This repeated centrifugation is cumbersome, time-consuming, and labor-intensive. Besides, cells treated by this process also experience unnatural physiological conditions. Another technique developed for obtaining age-specific population of yeasts involves labeling baby yeast cells with biotin and then retrieving these biotin-labeled cells at their older ages by using magnetic beads coated with avidin which specifically bind biotin (T. J. Smeal et al., Cell, 84, 633-642, 1996). This method involves artificially change cell properties and can be used only for those cells that can incorporate biotin onto their cell surface. The method also requires a special instrumentxe2x80x94a magnetic sorter.
Another technique that holds a promise for obtaining cells of the specific age is flow cytometry, if cells can be labeled at specific age and such labeling molecules can be tracked by the flow cytometry. However, if the collection process spreads over a long period of time, then a chronological age gap will still exist among the different cells. Thus, flow cytometry maybe inadequate and certainly is expensive for obtaining large number of age-synchronized cell population.
In essence, all existing xe2x80x9cone-stepxe2x80x9d synchronization methods, which desire to achieve long-term cell synchronization by just obtaining the initial cell population of the same division cycle stage or cell age, are theoretically unable to produce truly age-synchronized cell population in subsequent cultivation of the population. Those xe2x80x9cmultiple-stepxe2x80x9d synchronization methods, which required repeated centrifugal separations or requires first labeling the cells and then retrieving the labeled cells, can obtain truly age-homogenous cell population at the old ages but takes a lot of time, cost, and labor. Cells obtained through these methods often experience unnatural living conditions and these artificial stresses may interfere with the study of the physiological status of the cells.
There is no prior synchronization method that satisfies the two essential requirements for obtaining truly age-synchronized cell population: the collection of initial cell population at a very narrow range of specific cell age and the continuous cultivation of the initial cell population in a manner that avoids them being mixed with their offspring. Besides, in all existing methods for cell synchronization, the processes for producing synchronized cell population and processes for monitoring cell development/verifying cell synchronization status are separate tasks. This adds difficulty for real-time control of the cell synchronization process.
It is therefore a primary object of the present invention to develop a means for easily obtaining truly age homogenous cell population for long period of cultivation.
It is also an object of this invention to find a means for obtaining cell synchrony in a most natural and least stressful way.
It is another object of the present invention to find a method that can be used simultaneously for monitoring the development and synchrony of the cell population and for obtaining the synchronous cell population.
It is still another object of this invention to provide a scalable method of cell synchronization that can be adjusted to the different requirements.
It is also an objective of this invention to design a cell synchronization process that can be easily automated.
The present invention pertains to a generalized method and apparatus that can result in long-term age synchronization of cell population. It is based on a newly proposed theory of cell life that claims a parent-child relationship between the two cells formed from one cell. From this new understanding of cell life, it is understood that true age synchronization of any cell population can be achieved only through the absolute separation of the original parent cells from any of their offspring cells.
The present invention differs from all previous cell synchronization methods. First, an initial cell population is captured onto the surface within a very short period of time to ensure the highest age homogeneity in the initial cell population. Second, only the initially captured age-homogeneous cells are kept and their offspring are continuously removed so that the age purity of the initial population is maintained. Third, when using a transparent surface material to capture the initial cell population, the status of cell synchronization can be continuously monitored, either by installing a microscopic lens directly above one area of the cell-attached surface or by taking a piece of the surface for microscopic examination. This in-process monitoring allows collection of cells at the desired specific cell age and cell reproduction stage. Fourth, the initial cell populations can be captured on individual surface areas that are separately mounted. This allows multiple collections of cells at the different cell ages without disrupting the operation of overall process.
In comparing with the baby machine, the present invention obtains highly age-homogenous initial cell population and continuously maintains the age purity in the subsequent cultivation. In the baby machine, cells immobilized onto a surface come from an exponential-phase culture, which in fact contains cells of various ages, as indicated by the wide size distribution. Thus, without an age-differentiating measure, cells of any age can adhere to the surface. Besides, the contact time allowed for cells to adhere to the surface is too long relative to its length of cell reproduction cycle. This long duration of collecting initial cell population introduces a great age difference among the collected cells. The consequence of these shortcomings is that cells collected on the same surface do not divide in a synchronized fashion. When cell synchronization begins with an age-mixed population, long-term cell age synchronization will be difficult, if not impossible, to achieve. The present invention overcomes these shortcomings by obtaining only the newborn cells in a very short period of time. This will insure a high age synchrony in the initial cell population and. Furthermore, although baby machine can collect baby cells as the starting population for synchronization, it does not separate the offspring from the parent in the continuous cultivation of this initial population. Thus, age mixing occurs in all subsequent cultivation of the culture. The present invention overcomes this problem by constantly removing the offspring from the initially captured cells.
In comparing with the methods developed for obtaining old yeast cells, the present invention employs more natural and simpler procedures. The invention takes advantage of the adhering capability of some microorganisms and thus does not introduce any foreign substance or force in collecting these microorganisms. Alternatively, the methods may use a surface that has been made attractive to the cells that lack natural adhering capacity. Compared with the repeated centrifugations employed in the some methods for achieving long-term synchrony, the present invention represents a natural way of achieving cell synchronization.
Other advantages of the present invention include:
(a) low cost for equipments and reagents;
(b) high speed in obtaining synchronized cells;
(c) great flexibility for satisfying the different demand;
(d) convenience for on-line real-time monitoring of the synchronization process;
(e) opportunity for obtaining cells of different ages;
(f) feasibility for automation.

Method and apparatus for producing age-synchronized cells


In order to provide processor elements and programmable devices, which have little restriction on logical block arrangement and wiring, and which can improve a degree of integration, processor element 1 includes: arithmetic units 11 that perform arithmetic processing on the basis of functions which have implemented instruction sets generated in accordance with programs; registers 12 that store arguments of the functions; bypass switches 13 of the arithmetic units 11; bypass switches 14 of the registers 12; a connection setting unit 16 that switches the connections of function units 20; a multiplexer 17 that switches the input to the connection setting unit 16; a demultiplexer 18 that switches the output destination of the output from the connection setting unit 16; and a selection unit 15 that switches, in accordance with a state, the bypass switches 13, 14, the connection setting unit 16, the multiplexer 17 and the demultiplexer 18.

In recent years, a programmable device such as a field programmable gate array (FPGA) and a dynamically reconfigurable processor (DRP) has been used.
For example, PTL 1 discloses a programmable device. The programmable device disclosed in PTL 1 generates a configuration code for achieving a plurality of circuits having different features, and stores the configuration code in a memory, for each task to be executed. When the programmable device operates, a circuit appropriate for causing the programmable device to execute according to an operation state of a system is selected from among the plurality of circuits having different features, and a configuration code associated with the selected circuit is loaded from the memory to the programmable device. The programmable device starts processing with respect to input data by the selected circuit at a stage when loading of the configuration code is completed.

Processor element, programmable device, and processor element control method


A method and apparatus are provided for controllably dispensing flux on a substrate having a plurality of conductive terminals. Flux having a viscosity range between 10 centipoises and about 150 centipoises is sprayed on the substrate and the conductive terminals at a valve pressure range between about 1.5 psi and about 30 psi via a dispense nozzle of a flux dispenser. Upon a subsequent high temperature solder reflow process, the sprayed flux on the substrate is mostly removed by thermal decomposition to volatile species, thereby significantly reducing flux residue remaining on the surface of the substrate between the conductive terminals.

The present invention relates to semiconductor packaging technology, and more particularly to flip-chip and related chip scale semiconductor packaging technology.
A common task in the manufacture of microelectronic components involves the manufacture of single chip or multi-chip modules having input/output pins which are inserted into a substrate. The input/output pins provide the needed electrical connections to the integrated circuit chip or chips, which are subsequently connected to the substrate or carrier. In other presently known manufacturing processes, a chip is soldered directly to a printed circuit board. With either process, solder flux compositions have typically been applied to the pins in order to connect the component to the selected substrate, for instance, the printed circuit board.
As electronic devices become smaller and more dense, greater demand is placed on the ability to establish efficient, reliable interconnections from a semiconductor chip to a substrate. There are at least three well-known methods for interconnecting chips to substrate. Those three methods are (a) face-up wire bonding, (b) face-up tape-automated bonding, and (c) the flip-chip method. Among these three methods, the flip-chip methods is frequently chosen as a preferred method of semiconductor packaging for it allows the interconnection of high density devices having a large number of input and output paths. Also, the flip-chip method provides short conductivity leads from the chip to the substrate, a small device footprint, low inductance, high frequency capabilities, and good noise control.
As shown in FIG. 1B, a flip-chip is a semiconductor chip 10 that is mounted onto a substrate 18 with the surface of the chip 10 facing the substrate 18. Although several materials may be used to form an interconnection between the flip-chip 10 and substrate 18, solder is one of the more commonly employed materials for flip-chip bumps 12. In the solder interconnect process termed xe2x80x9ccontrolled-collapse chip connection xe2x80x9c(C4)xe2x80x9d, the solder bumps 12 are deposited on a wettable conductive terminal on the semiconductor chip 10. Then the semiconductor chip 10 is aligned with the substrate 18 so that the solder bumps 12 are directly over solder wettable terminals 20 of the substrate 18. The solder bump are then tacked to the substrate 18 and reflowed in the presence of solder flux, creating an electrical and mechanical connection from the chip 10 to the substrate 18 as well as a path for heat dissipation.
Typically, the chip-substrate joining process involves application of a flux on the chip 10 and/or the solder wettable terminals 20 of the substrate 18. As shown in FIG. 1A, flux 16 is manually brushed over the entire surface of the semiconductor chip 10 by a brush 14, including the previously formed flip-chip bumps 12. For the purpose of increasing cleaning efficiency, Low-solid fluxes, or xe2x80x9cno-clean fluxesxe2x80x9d, which contain small amounts, e.g., about 1% to 5% by weight of solids (activator and vehicle) and the remainder liquid solvent, such as isopropyl alcohol, are being increasingly used by circuit board manufacturers in an effort to eliminate the need to clean the circuit boards after soldering. Because of the small amount of solids within no-clean fluxes, the amount of residue left on the board is significantly reduced, as compared to the amount of residue remaining after the use of conventional rosin-based fluxes. These low-solid, no clean fluxes are particularly attractive because, as their name implies, flux cleaning of the circuit boards after soldering is not required, which results in a significant cost savings.
After flux application, the chip 10 is aligned to the substrate 18 having the flip-chip pads 20 on its surface, which is further facilitated by the flux viscosity and tackiness. The chip-substrate assembly is then subjected to solder reflow in a furnace under nitrogen or forming gas. In the subsequent cooling cycle of the thermal profile for joining, the solder hardens and at the same time, the residual flux vapors deposit on the various exposed surfaces.
Under the high temperature solder reflow environment, the flux is mostly removed by thermal decomposition to volatile species but a small fraction of these thermally activated species undergoes crosslinking reactions, resulting in resinous/carbonaceous byproducts as residue 22 (FIG. 1B) on the C4 connections and all other surfaces on the chip 10 and the substrate 18 that are exposed to the volatile species during the solder reflow professing. The flux residue 22 must be removed from all critical surfaces prior to further operation, otherwise it can lead to function failure during long term use due to stress corrosion during the exposure to temperature and humidity environment. Further need for removal of flux residue is dictated by the observation that if any residual film of flux residue remains on the substrate or device surface material, it causes detriment to the adhesion of C4 epoxy encapsulant or underfill which is required for enhanced C4 fatigue life and C4 reliability during production on-off cycles.
Therefore, there exists a need for improved and production worthy methodology which reduces flux residue from all critical surfaces.
These and other needs are met by the present invention which provides a method for depositing flux on a substrate having a plurality of conductive terminals to reduce flux residue from all critical areas of a chip surface. The present invention also provides an apparatus for dispensing flux on a substrate having conductive terminals to reduce flux residue from all critical areas of a chip surface.
The method in accordance with the present invention includes positioning a substrate having a plurality of conductive terminals on a predetermined location. Subsequently, flux having a viscosity range between about 10 centipoises and about 150 centipoises is controllably sprayed on the substrate at a valve pressure range between about 1.5 psi and about 30 psi to deposit the flux on the plurality of conductive terminals. In certain embodiments of the present invention, a flux dispenser equipped with a flux needle and containing the flux is used to deposit the flux on the substrate and the conductive terminals thereon.
The apparatus in accordance with the present invention comprises a flux fluid chamber containing flux having a viscosity range between about 10 centipoises and about 150 centipoises, and a flux dispense nozzle connected to the flux fluid and spraying the flux at a valve pressure range between about 1.5 psi and about 30 psi to deposit the flux on the plurality of conductive terminals. In certain embodiment of the present invention, the flux needle is used as the flux-dispensing nozzle.
Hence, the flux having a viscosity range between about 10 centipoises and about 150 centipoises is controllably sprayed on the substrate at a valve pressure range between about 1.5 psi and about 30 psi to deposit the flux on the substrate and the conductive terminals thereon. This has an advantage of significantly reducing flux residue remaining on the substrate after the high temperature solder reflow process, since the flux is mostly removed by thermal decomposition to volatile species during the high temperature solder reflow process. Thus, the present invention reduces the risk of the device""s functional failure during long-term use due to stress corrosion caused by exposure to temperature and humidity, thus achieving enhanced C4 fatigue life and reliability during production on-off cycle.
Additional advantages of the present invention will become readily apparent to those skilled in this art from the following detailed description, wherein only the preferred embodiment of the present invention is shown and described, simply by way of illustration of the best mode contemplated for carrying out the present invention. As will be realized, the invention is capable of other and different embodiments, and its several details are capable of modifications in various obvious respects, all without departing from the present invention. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive.

Controlled and programmed deposition of flux on a flip-chip die by spraying


A magnetic tape recording and playback apparatus includes a tape driving system for driving a tape, a recording/playing system for recording/playing/erasing and a linking device for mechanically linking the operations of the tape driving system with the recording/playing system. The tape driving system includes a motor, a gear train coupled to the motor and a reel shaft for rotating reels of the cassette. The gear train includes an planetary gear which swings. The planetary gear selectively rotates the reel shaft in correspondence with respective operation modes of the magnetic recording and playback apparatus. The linking device includes a cam coupled to the planetary gear and a head base mounting a recording/playing head. The cam transmits the driving power from the motor to the head base through the planetary gear. The head base moves corresponding to the shape of the cam and in association with the operation of the planetary gear. Operation such as recording and playing is carried out on the tape by the movement of the head base.

1. Field of the Invention
The present invention relates to a magnetic tape recording and playback apparatus in which modes of running the tape are switched in accordance with electric signal.
2. Description of the Background Art
Generally, a magnetic tape recording and playback apparatus comprises a tape driving system for running a cassette tape inserted thereto and a recording/playback system for recording/playing magnetic signals on the tape.
The tape driving system comprises, as basic elements, a motor serving as a power source, a pair of reel shafts engaging reels of the cassette tape and transmitting means for transmitting the rotation of the motor to the reel shafts.
The recording/playing system comprises a recording/playing head for recording magnetic signals on the tape or for reading magnetic signals recorded on the tape, and an erasing head for erasing the magnetic signals.
The basic operation modes of the magnetic tape recording and playback apparatus are a stopping mode, recording/playing mode, fast forwarding mode and rewinding mode. Various operation of the tape driving system and of the recording/playing system are combined to carry out prescribed operations in the respective operation modes. For example, in the recording/playing mode, the tape driving system rotates the motor so that a take-up reel of the cassette tape is rotated in a direction of taking up. At the same time, the recording/playing system moves forward a recording/playing head so that the recording/playing head is brought into contact with the surface of a tape running. The recording/playing head records or reads magnetic signals to and from the tape.
In the rewinding mode, the tape driving system rotates the motor to rotate a supply reel of the cassette tape. At the same time, the recording/playing system moves rearward the recording/playing head s that the recording/playing head is spaced away from the surface of the tape.
In this manner, various operation modes can be realized by controlling the operation of the tape driving system and the recording/playing system of the magnetic tape recording and playback apparatus. An example of a mechanism of the tape driving system is shown in U.S. Pat. No. 4,528,606. The tape driving mechanism shown in this example comprises a pair of rollers for transmitting rotation provided between a capstan shaft and a pair of reel shafts. The pair of rollers are rotatively attached to a rocking bracket. The rocking bracket is rotatively attached to the capstan shaft. A belt is wound around the pair of rollers and a pulley provided on the capstan shaft. The rotation of the motor is transmitted to the capstan shaft. The rocking bracket swings in a prescribed direction corresponding to the direction of rotation of the capstan shaft. By the swinging movement of the rocking bracket, either one of the pair of rollers is coupled to one of the reel shafts, so that the rotation is transmitted thereto.
An example of a mechanism of the recording/playing system is disclosed in U.S. Pat. No. Re. 32,007. The recording/playing head and the erasing head are mounted on a head base. The head base is movably attached on a chassis. The head base moves forward/rearward toward the surface of the inserted cassette tape. The head base is connected to a cam by means of a controlling lever. The cam is operated by a controlling motor. The controlling motor rotates in accordance with respective operation modes of the magnetic tape recording and playback apparatus. The cam moves forward/rearward the head base through the controlling lever corresponding to the operation of the controlling motor.
The mechanism of the tape driving system and the recording/playing system of a magnetic tape recording and playback apparatus is also shown in Japanese Patent Laying-Open Number 42659/1984. The tape driving system comprises a capstan shaft, a driving gear attached to the capstan shaft, a pair of planetary gears engaging with the driving gear and a rotary plate rotatably attached to the capstan shaft for rotatably supporting the planetary gear. The rotation of the motor is transmitted to the capstan shaft. The rotation of the capstan shaft swings the rotary plate in a prescribed direction. Consequently, one of the planetary gears engages with one of the reel shaft gears. The rotation of the motor is transmitted to the reel shaft gear through the capstan shaft, the driving gear and the planetary gear.
The recording/playing system comprises a head base on which the recording/playing head and the erasing head are mounted. The head base is movably attached on the chassis. The head base has its one end coupled to a turning lever connected to a plunger of a solenoid. The operation of the plunger of the solenoid moves forward/rearward the head base through the turning lever. That operation of the tape driving system and the movement of the head base are related with each other by means of an electric controlling system.
As described above, in the conventional magnetic tape recording and playback apparatuses, the mechanism of the tape driving system and that of the recording/playing system are independent from each other, and generally the prescribed operation modes are set by electric controlling means. Such structure is against the current trend of reducing the size of the magnetic recording and playback apparatuses, as it is large and the control system is complicated.

Magnetic tape recording and playback apparatus