A rechargeable battery or cell is disclosed in which the electrode active material consists of at least one nonmetallic compound or salt of the electropositive species on which the cell is based, and the electrolyte or electrolyte solvent consists predominantly of a halogen-bearing or chalcogen-bearing covalent compound such as SOCl.sub.2 or SO.sub.2 Cl.sub.2. Also disclosed are cell component materials which include electrodes that consist primarily of salts of the cell electropositive species and chemically compatible electrolytes. These latter electrolytes include several newly discovered ambient temperature molten salt systems based on the AlCl.sub.3 --PCl.sub.5 binary and the AlCl.sub.3 --PCl.sub.5 --PCl.sub.3 ternaries.

This invention relates to ambient temperature, rechargeable, non-aqueous, all-inorganic electrochemical cells. More specifically, this invention relates to such cells utilizing a new type of electrode in which the active material consists entirely of one or more nonmetallic compounds or salts of the electropositive species on which the cell is based (e.g., Li.sup.+, Na.sup.+), which is typically the same as that of the main charge-carrying species in the electrolyte. In addition, this invention relates to ambient temperature, non-aqueous, inorganic electrolytes for use in cells based on this new electrode type.
The ultimate goal of the research underlying the present invention is to develop improved rechargeable batteries operating at or near room temperature that provide high specific energy and power densities suitable for electric vehicles. To allow for a wide range of ambient conditions, the desired temperature range for electric vehicle batteries as envisioned in the long term by the U.S. Advanced Battery Consortium (USABC) is -40 to 85.degree. C. At present, the lead-acid battery is the leading candidate for full-scale on-the-road electric vehicles due to its mature yet continually evolving technology and well-established manufacturing base. Its chief limitation, however, is a low specific energy which stems from a low cell voltage due to its use of aqueous electrolytes and the relatively high cell component material molecular or formula weights. Thus, worldwide efforts have been in progress to develop alternate battery chemistries that provide higher specific energy and power densities as required to insure the long term economic viability of electric vehicles.
Lithium is among the most promising of rechargeable battery electrode active materials because of its high standard potential and low electrochemical equivalent weight. For many years, ambient temperature rechargeable lithium batteries have been in an ongoing state of research and development to provide lightweight, economical power sources for a variety of applications ranging from notebook computers and heart pacemakers to full-scale aerospace and transportation needs. A recent review of all the different approaches taken to date in the design of ambient temperature rechargeable lithium batteries is provided by Hossain (Chap. 36 in Handbook of Batteries, 2nd ed., ed. by D. Linden, McGraw-Hill, Inc., 1995).
From a review of the patent literature and other published studies pertaining to advanced batteries considered for use in electric vehicles, it appears that the majority of research in ambient temperature lithium rechargeable batteries has been concentrated almost exclusively on two main types of cells which differ according to the form the lithium active material assumes during cell operation, i.e., i) those using lithium metal anodes, or ii) those using certain solid materials for both electrodes that can reversibly intercalate Li.sup.+ cations. Both types of cells may utilize a variety of liquid or solid (e.g., polymer) electrolytes. In type (ii) cells, often referred to as Li-ion ("lion") cells, Li.sup.+ cations are shuttled back and forth between the electrodes during charging and discharging, and no free lithium metal is present. Li-ion cells often utilize porous carbon at the anode and lithiated first row transition metal oxides (e.g., Li.sub.x MnO.sub.2) at the cathode, but many deviations from this basic design exist, e.g., certain lithiated transition metal compounds with potentials sufficiently close to that of metallic lithium (e.g., Li.sub.x WO.sub.2) may be used as anodes, or porous carbon electrodes may be used at both the cathode and anode, each differing in the amount of surface area. Much research has and continues to be devoted to the development of new (and/or to the improvement of existing) materials with enhanced Li.sup.+ ion intercalation storage capabilities. At present, however, neither lithium metal anode nor Li-ion cells are sufficiently developed for large-scale commercial use in electric vehicle batteries. For lithium metal anode batteries, safety problems associated with metal dendrites abound, and for Li-ion-type batteries, current limitations regarding long-term storage and specific energy and power density need to be overcome.
The present invention, which makes use of all-metal salt electrodes, is a significant departure from conventional battery designs. A review of the prior art shows that there are relatively few designs using lithium and other lightweight, electropositive metals in which the electrode active metal assumes the form of a distinct salt phase during some stage of cell operation. U.S. Pat. No. 4,154,902 by Schwartz describes both primary and rechargeable ambient temperature, non-aqueous cells in which, during the charging stage, the electrode active material is in the form of a dithionite salt of an alkali or alkaline earth metal. In the cell design of Schwartz, the dithionite salt (e.g., Li.sub.2 S.sub.2 O.sub.4) is dissolved in a suitable anhydrous solvent together with another salt of the same metal with a higher solubility (e.g., LiClO.sub.4) to enhance the electrolyte metal cation conductivity, and SO.sub.2 is usually added at saturation. During charging, the electrode active metal is deposited in metallic form at the anode and SO.sub.2 is produced at the cathode. During discharging, the dithionite salt is reformed from metal cations produced at the anode by oxidation of the metal and S.sub.2 O.sub.4.sup.2- anions produced at the cathode upon reduction of SO.sub.2. Throughout cell operation, a steady supply of dithionite salt is provided by the battery design which employs a system for forced circulation of the electrolyte.
It is well known that in primary lithium metal anode cells employing SO.sub.2 as the cathode active material, lithium dithionite salt, which has a low solubility in SO.sub.2 as well as in most other electrolyte solvents, is typically formed during cell discharge and is deposited as an electronically insulating layer (but with some ionic conductivity) on the cathode current collector or substrate. Cell failure in such systems often occurs when the cathode current collector is entirely or almost entirely covered with solid Li.sub.2 S.sub.2 O.sub.4. Under these conditions, further cell operation is not possible, and cells in which the cathode current collector is coated with solid Li.sub.2 S.sub.2 O.sub.4 are generally not considered to be rechargeable.
Schwartz's invention is of interest in that it teaches that it is possible to utilize the reaction product of spent anode active metal and cathode depolarizer (i.e., dithionite salt) as an electrode active material in rechargeable cells, at least in some systems. However, Schwartz's invention differs fundamentally from the present invention in that the anode active metal is not always present in oxidized form but rather undergoes repeated oxidation and reduction during cell cycling (as in all metal anode cell designs). Also, the electrode active metal dithionite salt appears to be utilizable in Schwartz's cells only in the form of an electrolyte solute, and no dithionite (or other) salt phase is deposited in solid form at either electrode at any stage of cell operation.
Another important aspect in which the present invention differs from that of Schwartz is that, in the latter invention, the rechargeable version of Schwartz's cell is limited to only SO.sub.2 since the cell chemistry is based on the use of dithionite salt as active material, whereas in the present invention, a wide variety of liquid cathode materials can be utilized, and in combination with a wide variety of electrode solid phase compositions which are generally not restricted or fixed by the chemical composition of the liquid cathode employed. As discussed in more detail below, it is far more difficult, both in theory and in practice, to utilize an oxychloride as the cathode active material in rechargeable cells than it is to use SO.sub.2. Hence, in that connection, it should be noted that it is only in the primary versions of Schwartz's cell design (wherein temporary use is also made of dithionite, but only as a precursor to the formation of lithium metal anodes in situ) that SOCl.sub.2 and other oxychlorides can be used as cathode depolarizers; such substances are not an integral part of any of Schwartz's rechargeable cells.
U.S. Pat. No. 4,520,083 by Prater et al. describes an ambient temperature, non-aqueous, rechargeable cell having a reactive metal anode of the second kind, i.e., one that forms an insoluble product upon discharge in combination with a suitable electrolyte. In the cell design described therein, M.sup.+ cations (where M is the electrode active metal, e.g., Li) are expelled from the metal anode during discharging, and they immediately react with X.sup.- anions which are present in the electrolyte at a concentration much greater than that of M.sup.+ cations to form an insoluble metal salt, MX, which precipitates or deposits back on the anode. The electrolyte of this invention generally also contains a cathode depolarizer such as SO.sub.2. At the positive electrode, the cathode depolarizer is reduced to a product which can be either soluble or insoluble in the electrolyte. During charging, the slightly soluble active metal salt on the anode (MX) redissolves, the X.sup.- anions return to the electrolyte solution, and the active metal cation M.sup.+ is reduced back to metal form at the anode. At the positive electrode, the reduction product is reoxidized back to the original cathode depolarizer. As discussed by Prater et al., a low solubility in the electrolyte of both M.sup.+ cations and MX salt is believed to be necessary for this type of cell to work as effectively as possible. This condition is met by preparing electrolyte solutions which are at or near saturation in both M.sup.+ and MX. A large concentration of X.sup.- relative to M.sup.+ is provided for by adding another supporting salt, RX (wherein R is different from M), which is substantially more soluble in the electrolyte than MX. To bring M.sup.+ to saturation, a salt of M may be added to the electrolyte.
The cells of Prater et al. make use primarily of lithium (as well as other alkali and also alkaline earth metals) as the anode active material and multi-component electrolyte solvents consisting primarily of inorganic or organic compounds consisting of Group IIIA, IVA, VA, and VI elements, e.g., nitriles, ethers, cyclic ethers, sulfur oxides, and sulfur oxyhalides. For the cathode depolarizer, a number of possible redox couples were mentioned in the disclosure, e.g., Ag.sup.+ /Ag, X.sub.2 /X.sup.- (where X is a halogen), Fe(CN).sub.6.sup.3- /Fe(CN).sub.6.sup.4-, and thianthrene cation/thianthrene, but the Examples employ only SO.sub.2 as a cathode depolarizer which was cited as being the most preferred.
The invention of Prater et al. differs fundamentally from the present invention in that the anode active metal species, M, undergoes repeated oxidation and reduction during discharging and charging, as in conventional cells; hence, the anode active metal is not in the form of a solid salt phase at both electrodes during any stage of cell operation. Also, the present invention and that of Prater et al. differ in the type of predominant ionic charge carrier in the electrolyte; in the latter invention, M.sup.+ cations are not transported back and forth between the electrodes. Finally, it appears that Prater's invention is restricted to simple and demonstrably reversible redox couples such as, e.g., X.sub.n /X.sup.m- or X/X.sub.n.sup.m- (where m and n are integers), in contrast to the present invention.
It is well known that not only sulfur dioxide (SO.sub.2) but also thionyl chloride (SOCl.sub.2) and sulfuryl chloride (SO.sub.2 Cl.sub.2), have long been used as liquid cathodes in lithium primary batteries designed for very high specific energy and power density applications. In the development of improved electric vehicle batteries that can meet future energy and power requirements, it would be highly desirable to be able to exploit the promising properties of such cathode active materials in ambient temperature, rechargeable cells. Of these three liquid cathodes, the oxychlorides, i.e., SOCl.sub.2 and SO.sub.2 Cl.sub.2, are more preferred since they provide the highest cell voltages, but up until now, their use has been limited almost exclusively to primary cells. Sulfur dioxide (SO.sub.2) is the only one of these liquid cathodes that has been utilized to any significant degree in lithium and other anode active metal rechargeable batteries; this is most likely due to the much higher degree of reversibility of its redox couple. Besides those designs described above, rechargeable cells using a lithium metal anode, a catholyte of SO.sub.2 containing a salt such as LiAlCl.sub.4 added to impart a high Li.sup.+ conductivity, and carbon as cathode current collector are also known, e.g., the system described in U.S. Pat. No. 4,513.067 by Kuo et al.
U.S. Pat. No. 5,260,148 by Idota describes and ambient temperature rechargeable battery in which the anode active material consists of one or more lithium compounds or salts, Li.sub.p X, which are substantially insoluble in the electrolyte based on organic solvent. Here, X is an anion which may be either singly atomic or polyatomic and p is the anion valence of X. The electrolyte consists of an organic solvent containing a compound, A.sub.q Y.sub.r, where A is a cation which may be either singly atomic or polyatomic, and Y is an anion which may be either identical with or different from X provided that the lithium salt of Y is substantially insoluble in the electrolyte. The cathode active material consists of an anion-doped compound or compound containing a cation which is the same as A of the compound A.sub.q Y.sub.r in the electrolyte. In the Examples provided, A is a polyatomic organic cation such as tetrabutylammonium, tetraethylammonium, tetrapentylammonium, tetrabutylphosphonium, N-methylpyridinium, and N-methylpicolinium
When A is Li, there are two possibilities for an inorganic Li-containing cathode material according to Idota's disclosure, i.e., it may consist of a Li-doped transition metal chalcogenide such as Li.sub.x Mn.sub.2 O.sub.4 or Li.sub.x CoO.sub.2, or "a cathode material mixture may be prepared from the cathode active material by mixing it with the same ingredients as those used for preparing the anode material mixture." For A=Li, however, this implies that the electrolyte conductivity cannot be made very high, since the main claim specifies that the lithium salt of Y must have a low solubility in the electrolyte. Specific examples of cells in which A is Li were not provided, but in the disclosure, Idota states that for such cells, the electrolyte "is preferably based on a combination of the lithium compound and an inorganic lithium solid electrolyte. Further, lithium may be used therewith in such an amount that it dissolves slightly."
Idota's invention differs fundamentally from the present invention in several key aspects. Idota's invention for anode active material is restricted to organic solvent electrolytes. As will be shown, the present invention provides a wide variety of recipes for the electrode salt mixtures, far more than envisioned by Idota. Whereas Idota's invention is restricted to the use of Li as the anode active metal species, the present invention has been demonstrated on a wide variety of anode active metal species. Also, various additives such as, e.g., aliovalent salts that give rise to substantially improved electrode properties were discovered and developed, and are disclosed herein. The optimization of multi-component all-metal salt electrode compositions for A=Li is not considered in Idota's invention.
The present invention also makes advantageous use of certain liquid cathode materials which participate in a key way in the electrode half cell reactions, whereas Idota's invention is restricted to organic solvent electrolytes. These liquid cathodes include those for which the half cell reactions are highly irreversible, i.e., the sulfur oxychlorides SOCl.sub.2 and SO.sub.2 Cl.sub.2, and hence not amenable to conventional rechargeable cell designs. Such liquid cathodes would also be utilizable in Idota's invention for A=Li with either of the two possible types of inorganic cathode materials mentioned above, but that possibility was not mentioned in Idota's disclosure.
The present invention also addresses the problem of electrode-electrolyte compatibility, whereby for a given electrode material, suitable electrolytes are used so that high exchange current densities at the electrode-electrolyte interface can be realized. The exchange current density provides a measure of how quickly the determining half-cell reactions can take place, and thus, high exchange currents are well known to be necessary for achieving high current carrying capabilites and high power capacities in electrochemical cells. The present invention utilizes a variety of inorganic electrolytes which give rise to highly promising cell properties believed to arise from high exchange current densities. As will be shown, these electrolytes include not only the sulfur oxychlorides, for which such high exchange currents have previously been manifested by the high performance capabilities of Li primary batteries, but also certain newly-discovered ambient temperature molten salt electrolytes disclosed herein. Thus, another key aspect of the present invention is the discovery and development of compatible electrolytes for the metal salt electrodes suitable for larger size, high energy and power density rechargeable cells, a problem which Idota's invention does not address.
In contrast to SO.sub.2, the oxyhalide solvents, particularly SOCl.sub.2, have rarely been used in rechargeable batteries. This is because their practical use in such systems has generally been precluded by the high degree of irreversibility of the electroreduction reaction, which makes the in situ regeneration of any spent liquid cathode solvent impracticable. For primary lithium metal anode-SOCl.sub.2 cathode cells, the overall electroreduction reaction is EQU 4Li+2SOCl.sub.2.fwdarw.4LiCl+S+SO.sub.2 (1)
where the LiCl is deposited at the positive electrode current collector (typically porous carbon). A prerequisite for the use of either SO.sub.2 Cl.sub.2 or SOCl.sub.2 as a liquid cathode in any rechargeable cell is that some mechanism be provided for the facile regeneration of spent cathode from the electroreduction products. For SOCl.sub.2, a mechanism would have to be provided for the recombination and re-reaction of three distinct chemical species, i.e., S, SO.sub.2, and Cl.sub.2. For SO.sub.2 Cl.sub.2, the only electroreduction products are SO.sub.2 and Cl.sub.2, and hence, the reformation of SO.sub.2 Cl.sub.2 is a more straightforward process than that of SOCl.sub.2 because only two species are involved. Also, the SO.sub.2 Cl.sub.2 reformation reaction is known to be catalyzable by carbon.
Even for SO.sub.2 Cl.sub.2, however, very few studies have been published on the use of such liquid cathodes in rechargeable cells. In one study by by Smith et al. (J. Electrochem. Soc., 137, 602 [1990]), the rechargeability of the Li--SO.sub.2 Cl.sub.2 couple was demonstrated at room temperature on small prototype cells with lithium metal anodes and carbon cathodes and test cells with all-lithium reference, test, and counter electrodes using 1.5 M LiAlCl.sub.4 --SO.sub.2 Cl.sub.2 as the catholyte. Both types of cells were found to exhibit moderately good rechargeability and efficiency, but in all cases, the number of cycles was generally limited to well below 60 due to cell failure. As discussed by Smith et al. and shown by the data, there appear to be two main causes of failure in Li--SO.sub.2 Cl.sub.2 cells, i.e., lithium metal dendrite formation, and a slow rate of regeneration of spent SO.sub.2 Cl.sub.2 from Cl.sub.2 and SO.sub.2. The latter phenomenon may occur in conjunction with certain deleterious side reactions such as Cl.sub.2 attack of Li, resulting in a gradual depletion of SO.sub.2 Cl.sub.2 from the cell. Whichever mode of failure predominates appears to be dependent on a number of interrelated factors, including the prior state of cell charge, the inter-electrode separation distance, and whether the cell is anode- or cathode-limited.
In the Smith et al. study, the effects of changes in catholyte composition were studied for the small prototype cells. Increasing the LiAlCl.sub.4 concentration from 1.5 to 3.0 M was found to double the cathode cycle life, which was attributed to a faster dissolution of lithium dendrites in the more corrosive 3.0 M electrolyte. Adding SO.sub.2 was found to have no effect on the cathode efficiency, but the discharge voltage regulation was greatly improved. This improvement was attributed to the suppression of SO.sub.2 Cl.sub.2 dissociation by SO.sub.2 which eliminates dissolved Cl.sub.2 from the catholyte, thus restricting the cathode reduction reaction to SO.sub.2 Cl.sub.2 alone rather than a mixture of Cl.sub.2 and SO.sub.2 Cl.sub.2. Adding Cl.sub.2 and/or SOCl.sub.2 to this system failed to regulate the discharge voltage and degraded cathode cycling efficiency to half the baseline electrolyte value. This undesirable effect might be due to the type of anodes used in the cells of the Smith et al. study, i.e., metallic lithium, which may act more as chlorine scavengers rather than as promoters of the in situ regeneration of the SO.sub.2 Cl.sub.2 cathode.
U.S. Pat. No. 4,894,298 by Vukson et al. describes a high temperature alkali metal plus halide rechargeable cell with SO.sub.2 Cl.sub.2 catholyte. The most typical version of this cell consists of a negative electrode of sodium metal and a positive electrode which includes a solid NaCl and SO.sub.2 Cl.sub.2 catholyte to which NaAlCl.sub.4 and AlCl.sub.3 are usually added to impart a high Na.sup.+ ionic conductivity. During charging, Na.sup.+ cations are released from the NaCl at the positive electrode and are reduced at the negative electrode to metallic form. Also, a volatile reaction product is produced which is believed to consist mostly of Cl.sub.2 gas formed at the positive electrode by anodic oxidation of the Cl.sup.- anions from the NaCl. During discharging, the sodium metal at the negative electrode is oxidized to Na.sup.+ cations which migrate to the positive electrode wherein SO.sub.2 Cl.sub.2 is reduced to Cl.sup.- anions and SO.sub.2, the latter of which is believed to constitute most of the volatile reaction product that is a part of the discharging reaction. The Cl.sup.- anions combine with Na.sup.+ cations to reform NaCl at the positive electrode.
As Vukson et al. also teach, the ability to regenerate spent SO.sub.2 Cl.sub.2 catholyte in situ is essential to the rechargeability of any cell incorporating such material. Vukson et al. provide a physical means in the cell design whereby gaseous SO.sub.2 and Cl.sub.2 generated at the positive electrode during charging and discharging, respectively, can be stored and later recombined as necessary to regenerate the SO.sub.2 Cl.sub.2 catholyte. In that way, rechargeability of a cell utilizing SO.sub.2 Cl.sub.2 as a catholyte is made possible even though the types of electrode active materials employed in designs of the type utilized by Vukson et al. make it infeasible to generate SO.sub.2 and Cl.sub.2 simultaneously during cell operation. The invention of Vukson et al. is illustrative of the types of elaborate means that sometimes have to be employed to make it feasible for SO.sub.2 and Cl.sub.2 to recombine to reform SO.sub.2 Cl.sub.2.
As will be shown, an important aspect of the present invention is that it is now possible to utilize fully such high performance liquid cathodes as SOCl.sub.2 and SO.sub.2 Cl.sub.2 in ambient temperature rechargeable batteries. This aspect stems from the discovery that certain all-metal salt electrode compositions were found to work quite well with both SOCl.sub.2 and SO.sub.2 Cl.sub.2. Possible theories and chemical mechanisms underlying this discovery are given below (see "Summary of Invention"). The present invention is the first known wherein cathode redox couples more complex that those of type X.sub.n /X.sup.m- or X/X.sub.n.sup.m- can be utilized in rechargeable cells.
Besides those electrolytes based on SOCl.sub.2 and SO.sub.2 Cl.sub.2, the author also discovered several new families of ambient temperature, all-inorganic molten salt electrolytes that work well with many of the all-metal salt electrode compositions which are disclosed herein. These molten salts are based on the low-melting binary, AlCl.sub.3 --PCl.sub.5, to which either PCl.sub.3, POCl.sub.3, or PSCl.sub.3 may be added. The synergistic effects of combining all-metal salt electrodes with these electrolytes are believed to stem from higher exchange current densities at the electrode-electrolyte interface. Also, depending on the metal salts comprising the electrode solid phases, these molten salt electrolytes may also serves as liquid electrodes (usually cathodes) since they all contain components that may undergo a variety of redox reactions involving either the uptake or liberation of Cl.sup.- ions from the phosphorus-containing components (i.e., PCl.sub.5, PCl.sub.3, POCl.sub.3, and/or PSCl.sub.3). Such redox reactions are also considerably more complex than those of type X.sub.n /X.sup.m- or X/X.sub.n.sup.m-.
It is the principle object of the present invention to provide an alternative approach to the development of high specific energy and power density rechargeable batteries that are potentially suitable for electric vehicle applications. This objective is accomplished by the use of a new electrode design together with supporting all-inorganic cell component materials, and a demonstration of the viability of said electrode design and cell component materials in larger-size prototype cells.
It is a further object to provide a wide range of rechargeable cell component materials for the construction of batteries based on the new electrode design. These materials include not only new electrode compositions utilizing metal salts as the principle electrode active material, but also new ambient temperature molten salt electrolytes that possess all the desired materials properties and appear to work synergistically with most of the electrode compositions developed herein.
It is a further object to provide means, utilizing the new electrode design described herein, for the use of promising and complex liquid or soluble electrodes in a rechargeable cell. In particular, it is a further object to provide means for the exploitation of both SOCl.sub.2 and SO.sub.2 Cl.sub.2 as liquid cathodes for high specific energy and power density cells. This is accomplished by the development of compatible all-metal salt electrodes of suitable chemical composition, as well as the discovery of an electrochemical "pre-treatment" of the catholyte that further improves the cell performance.
It is a further object to provide fabrication procedures for the construction of larger-size cell prototypes that effectively utilize the most promising cell materials discovered to date.
Other objects and advantages of the invention will become apparent from the following description and examples thereof.

Ambient temperature, rechargeable cells with metal salt-based electrodes and a system of cell component materials for use therein


In the electron beam drawing method, the optimal irradiation amount of an electron beam in accordance with a drawing area ratio at each of drawing positions, is obtained prior to drawing a desired pattern by irradiating an electron beam on a sample. The optimal irradiation amount obtained is separated in a plurality of gradations as a correction amount for a reference irradiation amount of the electron beam. This separation is made finer as the drawing area ratio is higher. The representative correction amount data is determined for each of the plurality of gradations. The representative correction amount data determined is stored for each of the plurality of gradations, and a pattern is drawn on a sample with the optical irradiation amount corresponding to read data of the representative correction amount stored.

The present invention relates to an image picturing method and an image picturing device, which use an electron beam, and more specifically, to an electron beam image picturing method and image picturing device, which are effective for the correction of the proximity effect.
In the drawing of an image using an electron beam, the phenomenon called back scattering occurs, in which electron made incident on a substrate on which an image is to be written, scatters within the substrate and appears once again on the surface of the substrate. The range in which back scattering reaches (that is, the diameter of the back scattering) is dependent on the energy of incident electron and the material of the substrate.
As the incident energy becomes larger, the diameter of the back scattering becomes larger, and as the atomic number of the material of the substrate is larger, it becomes smaller. The ratio of the energy of the back scattering with respect to the incident energy is called back scattering coefficient, and the back scattering coefficient becomes larger as the atomic number of the material of the substrate is larger. However, for substrates of the same material, the coefficient may differ from one another depending upon the type of the light sensitive agent (resist) applied thereon.
The energy accumulated in a resist is the total of the energy of the incident electron and that of the electron back-scattered. In the case of a pattern having a drawing area ratio, the pattern is greatly influenced by the back scattering, and as compared with a pattern having a small drawing area ratio, the energy accumulated in the resist becomes larger for the same incident energy. The drawing area ratio used here is the ratio of the area of the image drawn to the area of desired region in the surface of the substrate.
The phenomenon in which the effective irradiation amount differs when the drawing area ratio differs within the region where the back scattering reaches, is called proximity effect. As a result of the proximity effect, patterns drawn with the same irradiation amount, will have resist pattern sizes different from each other when the drawing area ratio differs from one another. As a solution to this, the correction of the irradiation amount in accordance with the image drawing area ratio (the correction of proximity effect) is generally carried out. The correction amount can be obtained by calculation from the data of the pattern to be drawn, and the correction amount is stored as the irradiation amount correction data together with the pattern drawing data.
The irradiation amount correction data is stored usually as data of 256 gradations. As the number of gradations is larger, it is possible to make the correction of a higher efficiency; however the data amount becomes larger. Conventionally, the correction to be carried on is divided to correspond to 256 gradations at a certain width, which is equivalent to 0.7% of the reference irradiation amount for one gradation. Therefore, the correction amount of 0% to less than 0.7% is for the first gradation, the correction amount of 0.7% to less than 1.4% is for the second gradation, and so on.
As a pattern has a higher image drawing area ratio, the ratio of the back scattering energy occupied in the energy accumulated in the resist becomes larger, thus the contrast of pattern becomes poor. Therefore, the variance in the size of the resist pattern, which occurs due to the variance of the irradiation amount, differs depending upon the pattern drawing area ratio.
FIG. 1 shows the relationship between the pattern drawing area ratio and the amount of the variance in line width of a pattern, obtained in the case where the irradiation amount varies by 1 .mu.C/cm.sup.2. In the case where the pattern drawing area ratio is close to 100%, when the irradiation amount varies by 1 .mu.C/cm.sup.2, the line width of the resist pattern varies by about 23 nm, whereas when the drawing area ratio is close to 0%, the variance of the measurement of the line width can be limited small as about 10 nm for the same irradiation variance amount.
In the meantime, the correction amount is not in the form of continuous data, but is divided into 256 gradations, as described above. Since there are such gradations, stepwise differences, although they are small, are created in the correction amount data. For example, in the case where the correction amount for one gradation is 0.7% of the reference irradiation amount, an error of .+-.0.35% may be created. When this is applied to the resist whose reference irradiation amount 20 .mu.C/cm.sup.2, the error in the irradiation amount is .+-.0.07 .mu.C/cm.sup.2. Since the irradiation amount error is constant regardless of the drawing area ratio, in a region where the drawing area ratio is close to 0%, the error in dimension is about 0.7 nm, whereas in a region where the drawing area ratio is close to 100%, the error in dimension is about 1.6 nm. Thus, for different drawing area ratios, different effective irradiation amounts result. Therefore, the proximity effect correction efficiency differs from one case to another.
Further, usually, the optimal irradiation amount obtained when the drawing area ratio is 100% is assigned as a reference irradiation amount, and the range from a drawing area ratio of 100% to 0% is separated into 256 gradations to carry out the correction. Therefore, naturally, even in the case where the drawing area ratio is placed between 0% and 50%, the range between a drawing area ratio of 0% and that of 100% is separated into 256 gradations. Accordingly, the correction accuracy becomes poor.
In the meantime, there is recently a high demand of increasing the accuracy of photomasks used in the lithography step of the manufacture of semiconductors. More specifically, there is a demand of achieving a dimension accuracy of 10 nm (3 .sigma.) for a pattern on a photomask in the manufacture of a 0.13 .mu.m-device. There are a number of factors which causes an error in the pattern dimension of a photomask, for example, the error in the form of beam used in the electron beam drawing device, the variance in the irradiation amount, and the variation in the sensitivity of the resist. Therefore, it is required that the error in dimension which is due to the proximity effect correction should be 3 nm or less at least. There are some factors for errors caused due to the proximity effect correction, that is, for example, the error in the calculation of the proximity effect correction and the error of the corrected gradations. Here, it is preferable that the error in dimension due to the error of the corrected gradations should be 1 nm or less. Thus, the conventional proximity effect correcting method entails a problem that the error in dimension exceeds an allowable limit in the region where the drawing area ratio is large.

Electron beam image picturing method and image picturing device


A thermomorphic covering layer is applied to a heat-shrinkable body of thermoplastic material, e.g. a heat-shrinking sleeve adapted to surround and seal a cable splice so that when the heat-shrinking temperature is reached, the thermomorphic covering melts to form a continuous protective layer on the sleeve. It contains glass fibers or an insecticide or microbicide to protect the sleeve against pest deterioration.

Heat-shrinkable products have been used increasingly in recent years for a variety of purposes, including the sealing of cable or wire joints or splices and, more generally, the application of an insulating sleeve in electrical and like applications. A heat-shrinkable tubular section, hereinafter referred to as a heat-shrinkable sleeve, can be placed over a splice in a cable and subjected to heat from a radiant heating source, a burner, a contact heater or the like. The heat causes the shrinkable material to contract and form a tight seal around the joint which can be electrically insulating and hermetic.
Heat-shrinkable products can also be provided in the form of a tape which can be wrapped around electrical or other joints and which can be heated to the shrinking temperature to increase the tension of the type around the body to which it is applied and to effect fusion or adhesion of the inner surface of the heat-shrinkable material to the material to which it is applied.
In general with heat-shrinkable materials, the temperature development in the product is of considerable importance since the heat-shrinking operation requires a thermal softening and a subsequent hardening of the product to achieve the seal and the bonding to the body to which the product is applied. The temperature to which the material is brought is of special importance with heat-shrinkable materials which have an adhesive layer.
With temperatures which are too low, the adhesive layer may not melt and thus may not provide a satisfactory bond because there is insufficient adhesion of the shrunk material to the body to which it is applied.
With an excessively high temperature, the adhesive layer can be damaged or the heat-shrinkable material to which the adhesive layer is applied can be injured.
To avoid these drawbacks, it has been proposed to include thermally-sensitive coloring agents in or on the shrink products, these agents or substances providing certain color changes or color developments when appropriate temperatures are reached (see U.S. Pat. No. 3,816,335, U.S. Pat. No. 4,105,583, U.K. patent 1,511,053 and U.K. patent 2,038,478). Coatings of these thermally-sensitive coloring agents, however, provide no additional function and have not always been fully satisfactory.
The products made with these materials, for example, can be susceptible to insects, microorganisms and rodents and may suffer deterioration from such pests.
It is also known to provide a heat-shrinkable article of the aforedescribed type with at least one layer which, upon reaching the shrinking temperature, becomes transparent. The heat-shrinkable material or object can thus be provided of a particular color with a coloring agent, pigment or dyestuff which imparts a hue or color to the shrinkable material which is different from the color of the object to which the material is applied.
The heat-shrinkable article may itself comprise two cross-linked superposed layers of which only the inner layer is colored while the outer layer is not colored or is only weakly colored. In this system, the outer layer is not initially transparent, but rather is opaque to a greater or lesser extent so that the inner layer cannot be seen and its color is not ascertainable.
Only upon heating of the outer layer and the attainment of the desired temperature, which should lie as close as possible to the optimum shrinking temperature, does the outer layer become suddenly transparent so that the inner layer will become visible (see German patent document DE-OS 33 41 617).

Heat-shrinkable materials, especially for cable splices and junctions


A cutting tool [10] for use in forming circular and non-circular holes in a workpiece [16] includes a boring shaft [12] that is rotatable about an axis [15] and a boring head [14] that is secured to the boring shaft [12]. A cutting blade [46] extends beneath the bottom surface of the boring head [14] and is spaced apart from the axis [15]. A slug pin [58] extends from the bottom surface of the boring body to pierce and retain the slug after it has been cut to prevent it from falling into the workpiece [16].

Various apparatus are known for use in boring and cutting holes through workpieces. Conventional boring apparatus typically include a rotating cutting head which moves along an axis and into contact with a portion of a workpiece. These apparatus include a cutting blade extending forwardly from the cutting head and disposed generally parallel to and spaced from the axis to perform the cutting operation. The blade is positioned such that the rotation of the cutting head moves the blade along a circular path in a plane perpendicular to the axis. The hole is formed by advancing the cutting head along the axis towards the workpiece as it is rotated, until the cutting blade is moved completely through the workpiece.
A significant disadvantage of conventional boring tools is that both the hole which is formed, and the waste slug or plug which is cut from the workpiece, have side edges generally parallel to the axis. As a result, the waste slug or plug often falls through the hole into the workpiece. This is particularly undesirable where the tool is used to form holes in blow molded hollow workpieces, such as vehicle fuel tanks or the like, as the plugs are difficult to retrieve and must be manually removed. In an effort to prevent the slugs from falling into the workpiece, attempts have been made to cut tapered holes, such as disclosed in U.S. Pat. No. 5,653,560. Such devices, however, are expensive and complex, have numerous moving parts, often require computer feedback, and utilize large areas of space.
The apparatus described above are further disadvantageous in that they only allow for the cutting of holes in workpieces that are uniform or circular in shape. While various apparatus and techniques are known for cutting non-circular or arbitrary shaped holes in workpieces, they also suffer from a variety of significant disadvantages. First, these current apparatus and techniques require expensive technologies to control the operation of the cutting blade, such as CNC machinery, robot manipulation or other motion control or laser cutting. Additionally, current technologies for cutting non-circular holes generate chips during the cutting process. This also increases the cost of the process as it requires a separate vacuum step to remove any debris that has accumulated in the workpiece. This process also significantly increases the amount of time and expense required to cut holes in the workpiece.

Mechanically actuated chip-less boring head for forming a hole in a workpiece


An apparatus is configured for testing a light emitting diode interface. The apparatus includes an integrated network device having a configuration register and logic for generating LED outputs based on detected network events and stored configuration register values. A light emitting diode is associated with the register. A processor is configured to send a signal to the integrated network device to set the configuration register to cause operation of the light emitting diode independent of network events. Hence, a light emitting diode interface of an integrated network device such as a network switch can be tested without sending data packets to the network device.

1. Field of the Invention
The present invention relates to testing of integrated network devices such as integrated network switches configured for switching data packets between subnetworks.
2. Background Art
Local area networks use a network cable or other media to link stations on the network. Each local area network architecture uses a media access control (MAC) enabling network interface devices at each network node to access the network medium.
Switched local area networks are encountering increasing demands for higher speed connectivity, more flexible switching performance, and the ability to accommodate more complex network architectures. For example, commonly-assigned U.S. Pat. No. 5,953,335 discloses a network switch configured for switching layer 2 type Ethernet (IEEE 802.3) data packets between different network nodes; a received layer 2 type data packet may include a VLAN (virtual LAN) tagged frame according to IEEE 802.1p (802.1D) protocol that enables the network switch to perform more advanced switching operations. For example, the VLAN tag may specify another subnetwork (via a router) or a prescribed group of stations.
Light emitting diode (LED) interfaces are incorporated into integrated network devices such as an integrated network switch to drive LEDs for visual indications of network events occurring in the switch, for example, port transmit activity, port receive activity, port speed (10 Mbps or 100 Mbps) congestion at a port, a self test event, etc. In order to test the function of the LED interface, typically, an emulator is provided to send data packets to a network switch under test in such a manner to have the logic of the network switch cause activation of the LED. This testing procedure may be costly and time consuming in that this procedure requires actually sending and receiving data packets merely to turn the LED on and off.
There is a need to test the light emitting diode (LED) interface of an integrated network device without sending data packets to the network device for activation of the LED.
This and other needs are attained by the present invention, where a method for testing the light emitting diode interface of an integrated network device includes sending a signal to the integrated network device to set a configuration register in the integrated network device to cause operation of the selected light emitting diode, independent of network events.
Another aspect of the present invention provides an apparatus configured for testing a light emitting diode interface of an integrated network device. The apparatus includes an integrated network device having a register and logic for generating LED outputs based on detected network events and stored configuration register values. A light emitting diode is associated with the configuration register. A processor is configured to send a signal to the integrated network device to directly set the configuration register to cause operation of a light emitting diode, independent of the network events.
Hence, a light emitting diode associated with an integrated network device such as a network switch can be tested without sending data packets to the network device and bypassing the logic of the network device by directly causing operation of the light emitting diode.
Additional advantages and novel features of the invention will be set forth in part in the description which follows and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The advantages of the present invention may be realized and attained by means of instrumentalities and combinations particularly pointed in the appended claims.

Arrangement for testing light emitting diode interface of an integrated network device


A thermoplastic molding composition having improved physical properties is provided, the composition comprising an intimate admixture of a high molecular weight polyester, from about 0.1 to about 25% by weight, based on the total composition, of a copolymer of ethylene and vinyl acetate and a filler, said composition having been prepared by melt blending the polyester, the copolymer and the filler and further reacting the resultant blend in the solid state.

This invention relates to improved thermoplastic molding compositions and, more particularly, to improved thermoplastic polyester molding compositions.
High molecular weight linear polyesters and copolyesters of glycols and terephthalic or isophthalic acid have been available for a number of years. These are described inter alia in Whinfield et al, U.S. Pat. No. 2,465,319, and in Pengilly, U.S. Pat. No. 3,047,539, incorporated herein by reference. These patents disclose that the polyesters are particularly advantageous as film and fiber formers.
With the development of molecular weight control, the use of nucleating agents and two-step molding cycles, poly(ethylene terephthalate) has become an important constituent of injection-moldable compositions. Poly(1,4-butylene terephthalate), because of its very rapid crystallization from the melt, is uniquely useful as a component in such compositions. Workpieces molded from such polyester resins, in comparison with other thermoplastics, offer a high degree of surface hardness and abrasion resistance, high gloss, and lower surface friction.
Recently, block copolyesters, wherein the major portion of the repeating units are poly(1,4-butylene terephthalate) blocks, have been found to have enhanced impact resistance.
U.S. Pat. No. 3,937,757 teaches that the tracking resistance of unfilled poly(1,4-butylene terephthalate) compositions can be improved by the addition of from 5 to 50% by weight of a polyolefin or ethylene copolymer, containing at least 50% by weight ethylene units, thereto.
It has now been surprisingly discovered that if a polyester, a copolymer of ethylene and vinyl acetate, and a filler are intimately admixed by melt blending and the admixture post-reacted in the solid state, thermoplastic compositions exhibiting vastly improved impact resistance, as well as other excellent properties, such as high tensile strength, high flexural moduli and low warp are provided.


The viewfinder of a camera include one or more lens elements that zoom in coordination with the camera's taking lens, and normal/panoramic masking plates that pivot about horizontal axis in coordination, with moving masking plates for the camera's back frame opening or with signaling elements. Since the panoramic masking plates are not in the image plane, the aperture in a provided aperture plate is a horizontal slit opening, which provides a great depth of focus, to maintain image sharpness, when the masking plates are in the panoramic position.

A panoramic photograph is one that is made from a narrow portion of an exposure having a greater width-to-length ratio, e.g., 1:3 than a normal size photographic exposure. When panoramic photography is carried out, the area of the exposure corresponding to a fully sized frame outside the exposure of the panoramic size frame constitutes unexposed areas in which predetermined data may be recorded by a camera. Masks or masking plates may also be used to cover the back frame of a camera, to signal to a photofinisher that a panoramic photograph is desired to be printed.
Cameras have been developed for producing both panoramic and normal photographs. A camera that produces panoramic and normal size photographs has masking plates selectively movable for masking the field lens so as to form a picture frame of a panoramic size, or for exposing a larger portion of the field lens for producing an image of normal size. An actuating mechanism provided on the lens mount selectively sets the masking plates in either the panoramic or normal size position.
When switching from the normal to the panoramic mode, the mask appearing in the viewfinder of the camera is changed in coordination with the position of the masking plates masking the back frame of the camera to give an indication to the user of the camera, that the camera is in the panoramic mode. When the masking plates are in the panoramic mode, the masking plates limit the field of view through the viewfinder. Thus, the viewfinder will also indicate the field of view of the camera in the panoramic mode.
Cameras with which photographs can be taken with great ease are in widespread use as compact cameras. Typically, the movable masking plate is placed in the image plane of the camera in order to produce sharp masking edges in the viewfinder. Sometimes, however, because of space constraints the movable masking plate can not be placed in the image plane of the viewfinder. When the movable masking plate is placed in locations that are somewhat removed from the image plane, portions of the mask will appear fuzzy in the viewfinder.
Problems To Be Solved By The Invention
One of the disadvantages of locating the movable masking plate to positions that are not near the image plane is that portions of the framing mask will not be sharp when viewed in the viewfinder. This is not aesthetically pleasing and is annoying to a photographer.
Another disadvantage of the prior art is that framing of the photograph is less accurate and more difficult, since the framing mask viewed in the viewfinder will not have sharp and crisp borders.


A delay circuit, e.g., for a semiconductor device, having a plurality of cascade-connected stages that successively delay an input signal, may include: plural cascaded-connected delay devices representing instances of a first type of delay unit corresponding to the stages, respectively; plural resistance units coupled between a node having a source voltage of varying magnitude Vvar and odd-numbered ones of the delay devices, respectively; and plural capacitance units coupled between a node having another voltage Vuni of substantially uniform magnitude relative to Vvar and nodes representing the outputs of the odd-numbered delay devices; where corresponding ones of the plurality of capacitor units and the plurality of resistance units represent instances, respectively, of a second type of delay unit.

Semiconductor devices, e.g., , memory devices, etc., are generally provided with a delay circuit for adaptively delaying signals generated locally or for delaying externally-applied signals. Such a delay circuit has been used as a timing control component in semiconductor devices.
The delay circuit typically provided in this field has a chain configuration constructed of CMOS inverters, and resistances and capacitors. The delay chain uses an external or internal source voltage as an operating voltage. If the operating voltage increases, an amount of delay induced by such a delay chain is reduced based on a change of internal impedance, etc.
FIG. 1 depicts a delay circuit used with a semiconductor device, according to the Background Art. In FIG. 1, CMOS inverters INV1-INV4 are cascade-connected and represent four stages that constitute the delay chain. Each stage includes a CMOS inverter INVi, a capacitance unit Ci, and a resistance unit Ri. Resistance units R1, R3 are connected between each of odd-numbered CMOS inverters INV1, INV3 and a source voltage node, e.g., an externally-applied source voltage VEXT, respectively. Resistance units R2, R4 are each connected between each of even-numbered CMOS inverters INV2, INV4 and a node having ground voltage, respectively. Capacitance units C1, C3 are connected between VEXT and the outputs of odd-numbered CMOS inverters INV1, INV3, respectively. Capacitance units C2, C4 are connected between outputs of even-numbered CMOS inverters INV2, INV4 and a node having ground voltage, respectively.
Each of CMOS inverters INV1-INV4 functions as a unit delay. Resistance unit R1 and capacitance unit C1 together constitute another type of delay unit, namely an RC-type delay unit. Similarly, resistance unit R2 & capacitance unit C2, resistance unit R3 & capacitance unit C3 and resistance unit R4 & capacitance unit C4 constitute RC-type delay units, respectively.
An input signal IN that is provided at an input terminal is delayed by a delay operation of inverters INV1-INV4, resistance units R1-R4 and capacitance units C1-C4, and is then output at an output terminal as output signal OUT.
Operation of the Background Art delay chain of FIG. 1 will now be described. If a level of VEXT increases (due to any of various causes), current flowing through resistance units R1, R3 increases, and so the operating current of inverters INV1, INV3 increases. As such operating current increases, the delay times to complete the inverting operation (representing the delay times induced by inverters INV1, INV3) decrease, respectively.
Some types of apparatus can benefit from a delay chain's reduction in delay time associated with an increase in VEXT. For example, in a high-speed semiconductor memory device, operation of a sense amplifier (for sensing data of a memory cell) can cause a level of the array source voltage (which is the operating voltage applied to cells in a memory device) to drop momentarily. To prevent such a momentary drop in the array source voltage, the Background Art employs a scheme for adaptively overdriving an array source voltage generator (that generates the array source voltage) in which a control pulse is: generated in response to a sense amplifier enable signal; and is then passed through the delay circuit of FIG. 1. Accordingly, the width of the control pulse is reduced when the array source voltage increases, which reduces a degree to which the array source voltage generator is overdriven.

Delay circuit with more-responsively adapting delay time


A method is disclosed for scribing at least three grid contacts of a photovoltaic cell to electrically isolate them from the grid contact pattern used to collect solar current generated by the cell, and using the scribed segments for determining parameters of the cell by a combination of contact end resistance (CER) measurements using a minimum of three equally or unequally spaced lines, and transmission line modal (TLM) measurements using a minimum of four unequally spaced lines. TLM measurements may be used to determine sheet resistance under the contact, R.sub.sk, while CER measurements are used to determine contact resistivity, .rho..sub.c, from a nomograph of contact resistivity as a function of contact end resistance and sheet resistivity under the contact. In some cases, such as the case of silicon photovoltaic cells, sheet resistivity under the contact may be assumed to be equal to the known sheet resistance, R.sub.s, of the semiconductor material, thereby obviating the need for TLM measurements to determine R.sub.sk.

This invention relates to a method for measuring the resistivity of contacts on photovoltaic cells, and more particularly to a method for measuring contact resistivity of collector grid contacts using isolated segments of grid lines for contact end resistance and transmission line model measurements.
Measurement of contact resistance R.sub.c is of increasing importance in two semiconductor technologies: integrated circuits (IC) and photovoltaics (PV). The sizes of IC device features are continually decreasing, which causes an increase in the resistance of the conductor/semiconductor interface. A contact resistance R.sub.c of less than 10.sup.-6 ohm-cm.sup.2 is now desirable for very large scale integration(VLSI) applications. The practice is to produce a test pattern at some unused area of the VLSI. Conventional tests are then conducted to determine the parameters of the VLSI for quality control without affecting the operational circuit pattern.
Most PV manufacturers have not yet had to be concerned about contact resistance. Photovoltaic devices using crystalline silicon typically have contact resistance losses of less than 0.01% of the generated power. For nonconcentrating solar power applications, this loss is acceptable. However, if a PV concentrator cell is working at a 100-sun level, a change in the contact resistance can cause an appreciable power loss. Similarly, if the contact resistance of conductive coatings or metallizations on thin-film PV devices is too high, or changes with time, contact resistance can have important research and development implications. As a result of this increased interest, the various contact resistance measurement methods used for semiconductors have been examined.
Contact resistance can be measured by either ac or dc methods. Because ac methods introduce detrimental parasitic influences and, in common with dc measurement, require determination of small voltages or small voltage differences, only dc measurement techniques are of real interest. H. H. Berger reviewed the dc contact resistance measurement techniques in a paper titled "Contact Resistance and Contact Resistivity," J. Electrochem. Soc., Vol. 119, No. 4, pp 506-513, 1972. At that time he listed five different methods: twin contact, differential, extrapolation, interface probing and transmission line model (TLM). The analyses done by Berger showed that the differential, interface probing, and TLM approaches were potentially the three best. All three methods require specialized sample structures, although it is shown below that the TLM method can obviate this by use of modified portions of the standard PV-device grid-line metallization. Berger and others have improved on the TLM method.
More recently a direct contact resistance (DCR) measurement method was proposed by Proctor and Linholm in a paper titled "A Direct Measurement of Interfacial Contact Resistance," Electron. Device Letters, EDL-3 No. 5, May 1982, pp 294-296. This direct method has potential application in IC and PV research and development. However, the direct method requires three photolithographic steps to prepare a sample. This is a serious limitation when investigating samples of production crystalline PV devices. DCR measurement on many proposed thin-film PV devices would be impossible due to lack of a diffused layer. For these reasons, a different measurement approach is required for PV devices.
In all of the TLM approaches it is necessary to account for the effect of contact end resistance, R.sub.E. This effect was noted by Berger, supra. Later work reported by Harrison in a paper titled "Characterising Metal Semiconductor OHMIC Contacts," Proc. IREE Aust., pp 95-100, used the contact end resistance measurement and the contact resistance measurement to determine the attenuation constant for electrically short contacts. Subsequent work by Reeves and Harrison, reported in a paper titled "Obtaining the Specific Contact Resistance from Transmission Line Model Measurements," Electron. Device Lett., EDL-3 No. 5, May 1982, pp 111-113, extended the utility of contact end resistance measurement to the determination of modifications in sheet resistivity under contacts due to the alloying/sintering process.
The literature does not disclose any physical explanation for the phenomenon of contact end resistance. The best definition is by Harrison, supra: "R.sub.E is defined as the ratio of the contact output voltage V(d) to the contact input current I(o) when the contact output current is zero." While this definition is accurate, it does not provide a basis for understanding the phenomenon.
In a paper titled "Ohmic Contacts for VLSI Device Applications," Conf. on Microelectronics, Adelaide, Australia 12-14 May 1982, Reeves and Harrison showed a schematic representation of the various resistances found when measuring resistances of contacts. A similar representation is included here as FIG. 1. This shows where the contact end resistance may be found. Another view of a contact by Reeves and Harrison, and earlier by Berger in a paper titled "Contact Resistance on Diffused Resistors," Dig. Techn. Papers, 1969 IEE International Solid-State Circuit Conference (ISSCC) pp 160, 161, contains lines representing current flow and flux as shown in FIG. 2 herein.
The important concept here is the reduction of current flux across the metal-semiconductor interface as a function of distance from the leading edge of the contact. According to convention, the nature of a contact changes from an electrically short contact to an electrically long contact according to the following relationship: EQU d.gtoreq.2/.alpha. (1)
where:
d=contact length, cm PA1 .alpha.=attenuation constant, cm.sup.-1 PA1 R.sub.sk =sheet resistance under the contact, .OMEGA./.quadrature. PA1 .rho..sub.c =contact resistivity, .OMEGA.-cm.sup.2 PA1 R.sub.c =contact resistance, .OMEGA. PA1 R.sub.E =contact end resistance, .OMEGA. PA1 R.sub.sk =sheet resistivity under the contact, .OMEGA./.quadrature. PA1 .rho..sub.c =contact resistivity , .OMEGA.-cm.sup.2 PA1 d=width of collector grid line, cm PA1 w=length of segment of collector grid line, cm PA1 L.sub.1, L.sub.2 =line-to-line distances, cm
The attenuation constant is defined by: EQU .alpha.=(R.sub.sk /.rho..sub.c).sup.1/2 ( 2)
where:
If the electrically short contact (.alpha.d<2) is visualized as a combination of a high contact resistance R.sub.c and a low sheet resistance R.sub.sk under the contact, then some of the current between contact 1 and contact 2 in FIG. 1 will have to flow through the conductor/semiconductor interface at the right edge of contact 2. A voltage measurement between contact 2 and contact 3 will include the interface at the right edge of contact 2 and thus there will be a voltage between contacts 2 and 3 due to a portion of the current between contacts 1 and 2. That voltage is a measurement of contact end resistance R.sub.E for contact 2. If the contact is electrically long (.alpha.d.gtoreq.2), then there will be little or no current flow across the interface at the right edge of contact 2 and therefore a very small, or no, contact end resistance, R.sub.E, measured. The equations for contact resistance and contact end resistance from Berger, J. Electrochem. Soc., Vol. 119, No. 4, pp 506-513, 1972, have been reformulated as: EQU R.sub.c =(R.sub.sk .rho..sub.c).sup.1/2 /(w tan h [d(R.sub.sk /.rho..sub.c).sup.1/2 ]) (3) EQU R.sub.E =(R.sub.sk .rho..sub.c).sup.1/2 /(W sin h [d(R.sub.sk /.rho..sub.c).sup.1/2 ]) (4)
where:
Equations (3) and (4) show that contact resistance is dependent upon both the quality of the contact and the modification of the semiconductor surface due to application of the contact. Work by Reeves and Harison, Electron. Device Lett., EDL-3, No. 5, May 1982, pp 111-113 has shown that the sheet resistance of a lightly doped silicon surface (R.sub.s =2100 .OMEGA./.quadrature.) may change by a factor of 5 while a gallium arsenide surface may change by a factor of 20 when metal is applied by alloying or sintering. Heavily doped silicon (R.sub.s =40 .OMEGA./.quadrature.), however, should change very little due to metallization sintering since it is already degenerate. This fact allows the substitution of a measured sheet resistance, R.sub.s, value for the sheet resistivity under the contact, R.sub.sk, for most present production solar cells. For gallium arsenide or other compound semiconductors, if modification of the sheet resistivity due to contact application can be shown to be predictable, then the modified value can be used. This substitution should not affect process control inspection since the determination of contact resistivity of poor contacts (using .rho..sub.c .ltoreq.1.times.10.sup.-3 .OMEGA.-cm.sup.2 as a definition of a good contact) is relatively insensitive to sheet resistivity values. This relationship is illustrated in FIG. 3.
Most contact resistance measurements for process control are made by using the TLM method along with a contact end resistance measurement. The TLM measurement relies upon a special pattern of three unequally spaced parallel contacts and the following equations from Berger, J. Electrochem. Soc., Vol. 119 No. 4, pp 506-513, 1972: ##EQU1## where: R.sub.1, R.sub.2 =measured resistance values, .OMEGA.
Note that since most PV cells have equally spaced grid lines for optimum device performance, the TLM approach cannot be used without modification of the grid lines because the denominator of equations (5) and (6) becomes zero.

Method for contact resistivity measurements on photovoltaic cells and cell adapted for such measurement


Cell binding agent-drug conjugates comprising bridge linkers, and methods of using such linkers and conjugates are provided.

Proteins, specifically antibodies have been extensively used in therapeutic applications, in vitro assays as research reagents and in vivo as diagnostic tools or as therapeutic drugs (Gad, S. C. Drug discovery handbook, published by Wiley-Interscience, 2005). For many applications the protein needs to be modified with an interesting group, such as a cytotoxic drug, a radio label element or a chromphore molecule for use in therapy or a detection agent when used in diagnostics (Teicher, B. A. et al. Clin. Cancer Res. 2011, 17, 6389-97; Elsadek, B. et al., J. Control Release, 2012, 157, 4˜28). One of these applications, called antibody-drug conjugates (ADCs), which is the exquisite targeting ability of antibodies in combination with the cytotoxic action of anticancer agents, enables to target and deliver drugs to cancer cells leaving normal cells largely unaffected, has been intensely exploitation in the last two decades. In particular, since US FDA approvals of Adcetris (brentuximab vedotin) in 2011 and Kadcyla (ado-trastuzumab emtansine) in 2013, the applications of antibody-drug conjugate (ADC) as a promise targeted treatment of cancers have been exploded and almost every major pharmaceutical and biotech company has adopted this approach (Chari, R. et al, Angew. Chem., Int. Ed. 2014, 53, 3796-3827; Sievers, E. L. et al. Annu Rev Med. 2013, 64, 15-29; Mehrling, T. Future Oncol, 2015, 11, 549). Currently there are more than 50 ADC drugs in the clinic trials according to www.clinictrails.gov.
The first-generation ADCs, including Kadcyla and Adcetris, are produced through nonselective conjugation of native lysine amines or interchain cysteine thiols on an anti-body respectively to a cytotoxic drug. Since there are over 50 surface-exposed lysines and 8 hinge cysteine residues in IgG1 antibodies, this nonselective conjugation results in randomly cross-linkage of cytotoxic drugs to practically all areas of the antibody molecule, particularly having a diverse population of ADCs with a wide distribution of drugs per antibody (DAR) (Wang, L., et al. 2005 Protein Sci. 14, 2436; Hamblett, K. J., et al. 2004 Clin. Cancer Res. 10, 7063). Thus some of the undesired ADC subpopulation could lead to shorter circulation half-life, lower efficacy, potentially increased off-target toxicity and a wide range of in vivo pharmacokinetic (PK) properties (Hamblett, K. J. et al, Clin. Cancer Res. 2004, 10, 7063-7070; Adem, Y. T. et al, Bioconjugate Chem. 2014, 25, 656-664; Boylan, N. J. Bioconjugate Chem., 2013, 24, 1008-1016; Strop, P., et al 2013 Chem. Biol. 20, 161-167). In addition, with this classical conjugation, the batch-to-batch consistency in ADC production can be challenging and may require diligent manufacturing capabilities (Wakankar, A. mAbs, 2011, 3, 161-172).
Therefore, biotechnology companies and academic institutions are highly focusing on establishing novel reliable methods for site-specific ADC conjugation. So far, there are several approaches developed in recent years for site selective ADC preparation (Panowski, S, 2014, mAbs 6, 34). They include incorporation of unpaired cysteines, e.g. engineered reactive cysteine residues, called THIOMAB from Genentech (Junutula, J. R., et al 2010 Clin. Cancer Res. 16, 4769; Junutula, J. R., et al 2008 Nat Biotechnol. 26, 925-32; U.S. Pat. Nos. 8,309,300; 7,855,275; 7,521,541; 7,723,485, WO2008/141044), genetically introduced glutamine tag with Streptoverticillium mobaraense transglutaminase (mTG) (Strop, P., Bioconjugate Chem., 2014, 25, 855-862; Strop, P., et al., 2013, Chem. Biol. 20, 161-167; U.S. Pat. No. 8,871,908 for Rinat-Pfizer) or with Microbial transglutaminase (MTGase) (Dennler, P., et al, 2014, Bioconjug. Chem. 25, 569-578. US pat appl 20130189287 for Innate Pharma; U.S. Pat. No. 7,893,019 for Bio-Ker S.r.l. (IT)), incorporation of thiolfucose (Dennler, P., et al, 2014 Bioconjugate Chemistry 25, 569; Okeley, N. M., et al 2013 Bioconjugate Chem. 24, 1650), incorporation of unnatural amino acids through mutagenesis (Axup, J. Y., et al., 2012, Proc. Natl. Acad. Sci. 109, 16101-16106; Zimmerman, E. S., et al., 2014, Bioconjug. Chem. 25, 351-361; Wu, P., et al, 2009 Proc. Natl. Acad. Sci. 106, 3000-3005; Rabuka, D., et al, 2012 Nat. Protoc. 7, 1052-67; U.S. Pat. No. 8,778,631 and US Pat Appl. 20100184135, WO2010/081110 for Sutro Biopharma; WO2006/069246, 2007/059312, U.S. Pat. Nos. 7,332,571, 7,696,312, and 7,638,299 for Ambrx; WO2007/130453, U.S. Pat. Nos. 7,632,492 and 7,829,659 for Allozyne), Incorporation of selenocysteine into antibodies (Hofer, T., et al 2009, Biochemistry 48, 12047-12057; U.S. Pat. No. 8,916,159 for US National Cancer Institute), Convertion of cysteines located in the CXPXR consensus sequence to formylglycine (FGly) with formylglycine generating enzyme (FGE) (Drake, P. M., et al., 2014, Bioconjug. Chem. 25, 1331-1341. Carrico; Isaac S. et al U.S. Pat. Nos. 7,985,783; 8,097,701; 8,349,910, and US Pat Appl 20140141025, 20100210543 for Redwood Bioscience), and through glycoengineeringly introduction of sialic acid with the use of galactosyl- and sialytransferases (Zhou, Q., et al 2014, Bioconjug. Chem., 25, 510-520, US Pat Appl 20140294867 for Sanofi-Genzyme). These above methods have produced nearly homogeneous product profiles, but they are required anti-body-engineering processes and reoptimization of cell culture conditions. Moreover, expression yields for genetic encoding of an unnatural amino acid were typically not promisingly high enough (Tian, F., et al, 2014, Proc. Natl. Acad. Sci. U.S.A. 111, 1766-71) which has a significant impact on the cost of goods of the ADC. In addition, it has been known that ADCs obtained by conjugation to cysteine side chains often display limited stability in circulation, leading to premature disconnection of the cytotoxic payload before the tumor site is reached (Junutula, J. R., et al 2008, Nat. Biotechnol. 26, 925-32).
The disulfide bond structures of the four subclasses of IgG antibodies were known in the 1960s (Milstein C. Biochem J 1966, 101:338-351; Pink J R, Milstein C. Nature 1967, 214:92-94; Frangione B, Milstein C. Nature 1967, 216:939-941; Pink J R, Milstein C. Nature 1967, 216:941-942; Frangione B, et al. Biochem J 1968, 106, 15-21; Frangione B, Milstein C. J Mol Biol 1968; 33:893-906; Edelman G M, et al. Proc Natl Acad Sci USA 1969; 63:78-85; Frangione B, et al. Nature 196, 221:145-148, Spiegelberg, H. L. et al Biochemistry, 1975, 10, 2157-63). Disulfide bond structure is critical for the structure, stability, and biological functions of IgG molecules. Among the four subclasses of IgG antibodies, IgG1, IgG2, IgG3 and IgG4, each IgG contains a total of 12 intra-chain disulfide bonds; each disulfide bond is associated with an individual IgG domain. The two heavy chains are connected in the hinge region by a variable number of disulfide bonds: 2 for IgG1 and IgG4, 4 for IgG2 and 11 for IgG3. The light chain of the IgG1 is connected to the heavy chain by a disulfide bond between the last cysteine residue of the light chain and the fifth cysteine residue of the heavy chain. But, for IgG2, IgG3 and IgG4, the light chain is linked to the heavy chain by a disulfide bond between the last cysteine residue of the light chain and the third cysteine residue of the heavy chain (Liu, H. and May, K., 2012, mAbs 4, 17-23). On the ranks of the susceptibility of disulfide bonds in human IgG1 antibodies by experimental reduction, differential alkylation, and LC-MS analysis (Liu, H, et al Anal. Chem., 2010, 82, 5219-5226), inter chain disulfide bonds are more susceptible to reduction than intra chain disulfide bonds, and the disulfide bonds between the light chain and heavy chain were more susceptible than disulfide bonds between the two heavy chains. The upper disulfide bond of the two inter heavy chain disulfide bonds was more susceptible than the lower one. Furthermore, disulfide bonds in the CH2 domain were the most susceptible to reduction. Disulfide bonds in VL, CL, VH, and CH1 domains had similar and moderate susceptibility, while disulfide bonds in the CH3 domain were the least susceptible to reduction (Liu, H, et al Anal. Chem., 2010, 82, 5219-5226).
Based on the more susceptibility of inter chain disulfide bonds in human IgG1 antibodies, several institutions and companies adopted the chemically specific conjugation strategy through rebridging reduced interchain disulfide bonds of a native antibody, such as, using bromo or dibromo-maleimides, called next generation maleimides (NGMs) (Schumacher, F. F., et al 2014, Org. Biomol. Chem. 12, 7261-7269; UCL Cancer Institute), applying bis-alkylating reagents via a three-carbon bridge (Badescu, G., et al., 2014, Bioconjug. Chem. 25, 1124-1136., WO2013/190272, WO2014/064424 for PolyTherics Ltd), with di-substituted heteroaryl bridge (US Pat Appl. 2015/0105539 for Concortis Biosystem), or through di-maleimide as a bridge (WO2014/114207). We have also used bromo maleimide and dibromomaleimide linkers to conjugate both drugs and antibodies for a quite while (WO2014/009774, PCT/M2012/053554). However, these above bridge linkers were designed in the way to conjugate only one cytotoxic agents to a pair of disulfide bonds, and therefore at most of time they only produced ADCs at DAR less than 2 (drugs per antibody), due to limited numbers (about two pairs) of reduced disulfide bonds are more accessible for conjugation.
As one of the major issues for ADCs is the limited numbers or amount of cytotoxic compound that ultimately reaches the tumor, and the favorable DAR over 3 is much important factor for improvement of ADC therapeutical index (Epenetos, A. A. et al, Cancer Res., 1986, 46, 3183-3191; Chari, R. V. Acc. Chem. Res., 2008, 41, 98-107, Zhao, R. Y. et al, 2011, J. Med. Chem. 54, 3606-3623), we therefore disclose novel acetylenedicarboxyl linkers of this invention that not only are able to conjugate two or more drugs per linker for achieving higher DARs (≥4), but also can selectively rebridge pairs of reduced inter chain disulfide bonds on surface of antibody due to the nature of stretch-out triple bond of the acetylenedicarboxyl group, particularly when two cytotoxic agents are linked at both ends of the stretch-out bridge linker, forming a quite large size (>20 Å) of molecule which in turn hardly accesses to the other disulfide bond sites, such as reduced intra chain disulfide bonds beneath the antibodies. The acetylenedicarboxyl linkers of this invention therefore can be used for selective bridging the pairs of free thiols on the inter chain of antibody, which are generated by overloaded TCEP or DTT, and for producing an ADC having DAR (drugs per antibody) over four. And the over reduced pairs of thiol groups that are inaccessibly reached by the bridge linkers, particularly by the stretch-out acetylenedicarboxyl linkers containing two cytotoxic agents, can be recoupled (regenerated) by an oxide, e.g. dehydroascorbic acid (DHAA) or Cu(II), to form back disulfide bonds at the end of conjugation. In a word, these bridge linkers of the invention can make homogeneous production of specific ADCs in a simple manner.

Acetylenedicarboxyl linkers and their uses in specific conjugation of a cell-binding molecule


A hinge fastening structure and method of creating a hinge to box-section pillar joint which includes a fastener extending from the pillar outer panel to the pillar inner panel wherein the fastener includes first and second threaded portions of substantially identical pitch but different diameters adjacent to the head and the tip thereof respectively. The fastening structure and method may also be applicable for attaching other forms of hardware to box-section structures.

In general, automotive door hinges are attached to the hinge pillar of a vehicle by means of bolted or welded connection. The hinge pillar is usually a vertically oriented box structure constructed from an inner hinge pillar panel and an outer hinge pillar panel. With few exceptions, it is generally accepted that the door hinges are attached to the outer hinge pillar panel only.
If an automotive door hinge is connected to the outer hinge pillar panel substantially as shown in FIGS. 7 and 8, the phenomenon known as, "oil canning" occurs in zone A of FIG. 7. This oil canning occurs due to the outer hinge pillar panel being of inadequate gauge to carry the sag and open overload forces imparted by the door. When a load is placed on the hinge, the outer hinge pillar panel will tend to flex in the vicinity of the hinge in the manner of the base of an oil can. This can lead to the creation of a permanent set in the outer hinge pillar panel and will ultimately lead to fit and finish problems with the door system as it becomes misaligned with the surrounding body structure. This will also tend adversely to affect the opening and closing of the door system as a whole.
Outer hinge pillar panels in isolation tend to be structurally incapable of carrying door hinge loads and usually require some form of secondary reinforcement. However, the completed hinge pillar structure, constructed from the outer and inner hinge pillar panels is far stiffer than its constitutive components and is capable of carrying much larger loads. A reinforcing member adjacent the outer hinge pillar panel, as illustrated in FIG. 8, has been used to help reduce oil canning, but the results so achieved have been less then desirable.
It has been previously proposed to use a fastener to fasten the hinge through the outer hinge pillar panel to the inner hinge pillar panel including a tube surrounding the fastener which acts as a spacer to ensure that the outer hinge pillar panel and the inner hinge pillar panel do not collapse towards one another. This arrangement possesses the advantage of spreading the applied hinge loadings into the entire pillar rather than concentrating them on the outer hinge pillar panel and therefore significantly reduces oil canning. However, inclusion of the tube makes manufacturing the joint extremely complex.
In the prior art it is also known to weld hinges to the hinge pillar. The structure includes a hinge essentially welded to the outer hinge pillar panel, passing through the pillar and tack welded to the inner hinge pillar panel. This again offers the advantage of spreading the applied hinge loadings into the entire pillar rather than concentrating them on the outer hinge pillar panel. However, such a hinge is difficult to repair. In addition, often water may enter the hinge pillar if the weld is not properly completed leading to rust problems. An example of such a device is found in a hinge integral with a hinge pin receiving opening manufactured by Ed Scharwachter GmbH & Co. LG which is welded, not fastened, to the hinge pillar.
The present invention overcomes the problems of the prior art while providing for a strong and stable fastening structure and joint. The present invention also provides a low cost and simple means of fastening a door hinge to a vehicle.
It is therefore a basic objective of this invention to provide a hinge fastening structure and a method of creating a hinge joint which is simple, efficient and effective.
It is a further object of this invention to provide a hardware fastening structure and a method for attaching hardware to box-section structures.
It is a further object of the invention to provide a fastening structure and method of fastening which improves the overall performance of the hinge joint particularly with regard to resistance to applied loads.
It is a further object of the invention to provide a hinge fastening means with reduced weight.
It is a further object of the invention to provide a hinge fastening structure with improved rigidity.
It is a further object of the invention to provide a novel fastener for mounting hinges to hinge pillars.
Further and other objects of the invention will become apparent to those skilled in the art when considering the full summary of the invention and the more detailed description of the preferred embodiments illustrated herein.

Hinge fastening structure and method of creating a hinge pillar joint