A novel millet cultivar, designated GG102, is disclosed. The invention relates to the seeds of millet cultivar GG102, to the plants of millet GG102 and to methods for producing a millet plant produced by crossing the cultivar GG102 with itself or another millet variety. The invention further relates to hybrid millet seeds and plants produced by crossing the cultivar GG102 with another millet cultivar.

The present invention relates to a new and distinctive millet cultivar, designated GG102. The term "millet" is applied to various grassy crops whose seeds are harvested for human food or animal feed. Compared to other cereal grains, millets are generally suited to less fertile soils and poorer growing conditions, such as intense heat and low rainfall and require shorter growing seasons.
The earliest recorded document about millet reports that it was a "holy plant" in China around 2800 BC. As an ancient staple of India, Egypt, and North Africa, millet was once dominant commodity; as wheat is today.
Millet is generally considered a minor crop in the U.S. because it has lost a great deal of importance as a cereal crop in favor of other cereal crops such as wheat and rice. However, millet is becoming more important in the U.S. due to its advantages as a rotational or cover crop as well as its use in the hunting industry when planted to attract wild foul, for example ducks and geese.
Millet prefers hot summers and is very drought-resistant once established, making it a great grain plant for most of North America, including the desert states. It will not thrive in the cool wet summers of the Pacific Northwest, British Columbia, or Northeastern Maine and Canada. In regions where summers are potentially cool and wet, millet should be planted in a sunny, well-protected location.
Millet can be grown as a sole crop, mixed crop or as an intercrop. Under traditional cropping systems, millets are largely grown as a component of mixed or intercropping patterns than as a sole crop. This is mainly because of the numerous advantages associated with the intercropping/mixed cropping systems.
Millets include five genera, Panicum, Setaria, Echinochloa, Pennisetum, and Paspalum, all of the tribe Paniceae; one genus, Eleusine, in the tribe Chlorideae; and one genus, Eragrostis, in the tribe Festuceae. The most important cultivated species of millet are foxtail (Setaria italica), pearl or cattail millet (Pennisetum glaucum), proso (Panicum miliaceum), Japanese barnyard millet (Echinochola crusgalli), finger millet (Eleusine coracana), browntop millet (Panicum ramosum), koda or ditch millet (Paspalum scrobiculatum), and teff millet (Eragrostis tef).
The present invention relates to Echinochola crusgalli, commonly know as Japanese Millet but also called barnyard millet or billion dollar grass. Japanese millet is grown principally as a forage grass. Japanese millet is usually grown as a late-season green feed in temperate climates with humid or sub-humid conditions. It makes the most rapid growth of all millets under favorable weather conditions, ordinarily producing ripe grain in 45 days after seeding. The ordinary growth habit of this annual grass is an erect plant 2–4 ft tall with a panicle inflorescence made up of 5–15 sessile erect branches. Spiklets are ordinarily brownish to purple and are borne on one side of each branch. Seeds are slightly longer than wide and are larger than those of barnyardgrass. Japanese millet makes its best growth on good soils. It is not ordinarily subject to major fungal diseases; it is susceptible to several species of head smuts.
Millets are generally grown on less fertile soils. All millets respond to nitrogen and phosphorus fertilizers, but there are only broad guidelines on fertility practices for millets. Nitrogen requirements for heavy forage production and heavy grazing will likely be double those required for hay or seed crops. Phosphorus requirements will also be higher than those for hay or seed crops. Nutrient requirements include potassium, sulfur, calcium, magnesium, iron, copper, boron, manganese, zinc, molybdenum, and chlorine. One or more of these nutrients may be limiting in the less fertile soils used by millet producers.
There are numerous steps in the development of any novel, desirable plant germplasm. Plant breeding begins with the analysis and definition of problems and weaknesses of the current germplasm, the establishment of program goals, and the definition of specific breeding objectives. The next step is selection of germplasm that possess the traits to meet the program goals. The goal is to combine in a single variety an improved combination of desirable traits from the parental germplasm. These important traits may include higher seed yield, resistance to diseases and insects, better stems and roots, tolerance to low temperatures, and better agronomic characteristics on grain quality.
Choice of breeding or selection methods depends on the mode of plant reproduction, the heritability of the trait(s) being improved, and the type of cultivar used commercially (e.g., F1 hybrid cultivar, pureline cultivar, etc.). For highly heritable traits, a choice of superior individual plants evaluated at a single location will be effective, whereas for traits with low heritability, selection should be based on mean values obtained from replicated evaluations of families of related plants. Popular selection methods commonly include pedigree selection, modified pedigree selection, mass selection, and recurrent selection, or a combination of these methods.
The complexity of inheritance influences choice of the breeding method. Various recurrent selection techniques were used to improve quantitatively inherited traits controlled by numerous genes. The use of recurrent selection in self-pollinating crops depends on the ease of pollination, the frequency of successful hybrids from each pollination, and the number of hybrid offspring from each successful cross.
Each breeding program should include a periodic, objective evaluation of the efficiency of the breeding procedure. Evaluation criteria vary depending on the goal and objectives, overall value of the advanced breeding lines, and number of successful cultivars produced per unit of input.
Promising advanced breeding lines are tested and compared to appropriate standards in environments representative of the target area. The best lines are candidates for new commercial cultivars; those still deficient in a few traits may be used as parents to produce new populations for further selection.
Development of new cultivars is a time-consuming process that requires precise forward planning, efficient use of resources, and a minimum of changes in direction.
One method of identifying a superior plant is to observe its performance relative to other cultivars. If a single observation is inconclusive, replicated observations provide a better estimate of its genetic worth.
The goal of plant breeding is to develop new, unique and superior millet cultivars and hybrids. The breeder initially selects and crosses two or more parental lines, followed by self-pollination and selection, producing many new genetic combinations. The breeder has no direct control at the cellular level; therefore, two breeders will not develop the same line, or even very similar lines, having the exact same traits.
The cultivars which are developed are unpredictable. This unpredictability is because the breeder's selection occurs in unique environments, with no control at the DNA level (using conventional breeding procedures), and with millions of different possible genetic combinations being generated. A breeder of ordinary skill in the art cannot predict the final resulting lines he develops, except possibly in a very gross and general fashion. The same breeder cannot produce the same cultivar twice by using the exact same original parents and the same selection techniques. This unpredictability results in the expenditure of large amounts of research monies to develop superior new millet cultivars.
Pedigree breeding is used commonly for the improvement of self-pollinating crops. Two parents which possess favorable, complementary traits are crossed to produce an F1. An F2 population is produced by selfing one or several F1's. Selection of the best individuals may begin in the F2 population; then, beginning in the F3, the best individuals in the best families are selected. Replicated testing of families can begin in the F4 generation to improve the effectiveness of selection for traits with low heritability. At an advanced stage of inbreeding (i.e., F6 and F7), the best lines or mixtures of phenotypically similar lines are tested for potential release as new cultivars.
Mass and recurrent selections can be used to improve populations of either self- or cross-pollinating crops. A genetically variable population of heterozygous individuals is either identified or created by intercrossing several different parents. The best plants are selected based on individual superiority, outstanding progeny, or excellent combining ability. The selected plants are intercrossed to produce a new population in which further cycles of selection are continued.
In a multiple-seed procedure, millet breeders commonly harvest one or more seeds from each plant in a population and thresh them together to form a bulk. Part of the bulk is used to plant the next generation and part is put in reserve. The procedure has been referred to as modified single-seed descent or the pod-bulk technique.
The multiple-seed procedure has been used to save labor at harvest. It is considerably faster to thresh panicles with a machine than to remove one seed from each by hand for the single-seed procedure. The multiple-seed procedure also makes it possible to plant the same number of seeds of a population each generation of inbreeding. Enough seeds are harvested to make up for those plants that did not germinate or produce seed.
Proper testing should detect any major faults and establish the level of superiority or improvement over current cultivars. In addition to showing superior performance, there must be a demand for a new cultivar that is compatible with industry standards or which creates a new market. The introduction of a new cultivar will incur additional costs to the seed producer, the grower, processor and consumer; for special advertising and marketing, altered seed and commercial production practices, and new product utilization. The testing preceding release of a new cultivar should take into consideration research and development costs as well as technical superiority of the final cultivar. For seed-propagated cultivars, it must be feasible to produce seed easily and economically.
Despite the importance of millets, production has remained low. Low yields of millets are generally attributed to lack of high yielding hybrids and to the fact that these crops are largely grown as rainfed crops.


The present invention allows a high-speed printing by a print head in which nozzles are arranged with a high density to reduce eddy flow caused between the print head and a print medium, providing an image with a high quality. Thus, the present invention allows the same printing region of the print medium to be sequentially printed by the respective nozzle arrays provided in the print head in accordance with image data thinned-out by the mask pattern M, thereby completing the image by multi-pass. Then, a plurality of pieces of image printed to be printed to the same printing region at which the nozzle arrays pass in one pass are alternately thinned-out by different high and low thinning-out ratios in the direction in which the nozzles are arranged.

1. Field of the Invention
The present invention relates to an ink jet printing method and an ink jet printing apparatus printing apparatus which print an image on a print medium by using an ink jet print head having a nozzle array in which nozzles for ejecting ink are arranged with a high density.
2. Description of the Related Art
With the diffusion of information processing devices and communication devices (e.g., computer, word processor), output devices for outputting digital image according to digital image information processed by the information processing devices have been increasingly required. One of these output devices is an ink jet printing apparatus printing apparatus that ejects ink droplets to form dots on a print medium to form an image. This ink jet printing apparatus printing apparatus has been widely used. This ink jet printing apparatus printing apparatus uses a print head that is designed, in order to improve the printing speed and the resolution of a printed image, to include a great number of integrated and arranged ejecting sections (hereinafter also referred as nozzles). The ejecting section consists of an ink ejecting port for ejecting ink droplets, a fluid path, and a printing element or the like.
Furthermore, there has been recently another demand for the output of a color printed image. Thus, an ink jet printing apparatus printing apparatus for printing a color image performs a printing operation using not only a print head for ejecting black ink but also print heads for ejecting a plurality of color inks. In the printing operation, the print heads have no contact with a print medium, thus providing a printing operation with low noise. The ink jet printing apparatus printing apparatus also can print an image having a high resolution with a high speed by arranging the nozzles with a higher density. Furthermore, this type of ink jet printing apparatus printing apparatus does not require a special processing (e.g., development, fixing) to a to-be-printed material (e.g., plain paper). Thus, this type of ink jet printing apparatus printing apparatus has various advantages such as the one providing a high quality image with a low cost. An on-demand-type ink jet printing apparatus printing apparatus in particular can provide a color image easily and can be downsized and simplified and thus is expected to create a growing demand in the future. With the increasing demand for a color-printed image, ink jet printing apparatus printing apparatuses are required to provide an image having a higher quality with a higher speed.
On the other hand, with the background of the recent technical progress for the integrated arrangement of nozzles, a print head having a further higher density and a longer length is becoming possible. Generally, a print head having a high density and a long length is called a long print head. This long print head can increase the width of a region that can be printed on a print medium by one printing scan to the print medium when compared to a case where a conventional short print head is used. Thus, this technique has been further developed as a useful technique for realizing a high-speed printing that has been conventionally impossible while maintaining a high image quality equal to that of a conventional design.
However, in the case of the ink jet printing apparatus printing apparatus as described above that uses a long print head having a high density, a problem as described below may be caused.
Specifically, when a long print head in which nozzles are arranged with a high density simultaneously ejects a great number of ink droplets while performing a printing scan by the print head or a scan of a print medium with a high speed, the print head and the print medium have therebetween irregular air current (eddy flow). This causes a problem that positions to which ink droplets land on the print medium are fluctuated. Furthermore, it has been known that the eddy flow between the print head and the print medium has a significant influence on how the ink droplets are ejected, which is also one of the causes of the deterioration of an ink landing accuracy. Another problem is that the fluctuation of the ink landing positions as described above causes the image to have a stripe-like or spiral-like uneven density, remarkably deteriorating the image quality. This has been hindrance to the realization of the printing of a high-quality image with a high speed.
As a technique for solving the stripe-like uneven density as described above, techniques disclosed in Japanese Patent Laid-Open No. 2001-18376 or Japanese Patent Laid-Open No. 2002-96455 are known.
Japanese Patent Laid-Open No. 2001-18376 discloses a technique in which nozzle arrays provided in a print head are divided to the printing ones and no-printing ones with a fixed pitch and the fixed pitch is further minutely divided. This technique can cause the stripe uneven density (stripe-uneven printing) to be the one that is difficult to be visually recognized.
Japanese Patent Laid-Open No. 2002-96455 also discloses a mask pattern for allocating, when a printing method is used by which a plurality of main scans complete an image within the same printing region, the operation for providing the image within the same printing region to a plurality of main scans. This mask pattern is set so that the end part side of the nozzle arrays have a higher thinning-out ratio than that of the center side. The use of this mask pattern can reduce the frequency at which the end part nozzle is used, thereby eliminating the uneven density caused by twisted eject from the end part nozzle.
However, the techniques according to the above Patent References still have room for improvement in that deterioration of an image due to eddy flow caused between a print head and a print medium is not sufficiently avoided. Specifically, the eddy flow caused between a print head and a print medium may be caused not only at the end part of the nozzle array but also at the entire region of the nozzle array. Influence by eddy flow between nozzle arrays also cannot be ignored. Thus, it is difficult for only the conventional techniques to avoid the deterioration of an image due to the generation of the eddy flow.
What is required for ink jet printing apparatus printing apparatuses in the future is to realize a printing of an image with both of a further higher speed and a further high quality. To do so, the deterioration of the quality of an image due to the eddy flow as described above needs to be improved.

Ink jet printing method and ink jet printing apparatus


A pressurized-flow self-cleaning whirlpool tub system includes a plurality of water/air jets arranged to introduce air-entrained water jets into a tub basin and a suction outlet from which water in the tub basin is withdrawn. A water distribution circuit is connected to each of the water/air jets for delivering water to each water/air jet. A recirculation pump receives water from the tub basin, pressurizes the water, and delivers the pressurized water to the water distribution system. A cleaning-agent dispenser is provided to receive a cleaning agent in liquid or solid form and mix the cleaning agent with water from the pressurized water supply. In a cleaning mode of operation, a suction valve is closed and the cleaning agent is introduced into the water carrying conduits to effect pressurized cleaning of the water contacting surfaces of the water pathway.

The present invention relates to a pressurized-flow self-cleaning whirlpool tub system and, more particularly, to a self-cleaning whirlpool system and method that is both relatively simple in design and efficient in use.
Whirlpool tub systems typically include a tub structure which have water/air jets designed to introduce streams of pressurized water and air into the tub. Water is typically withdrawn from the tub through a suction inlet, pressurized in a recirculation pump, and distributed to the water/air jets through a water distribution line for re-introduction into the tub basin.
During normal use, the recirculated water includes various types of contaminants, including dirt, bacteria, skin cells, and oils. The contaminants are deposited as a thin layer on the interior surfaces of the various water-carrying conduits and represents a sub-optimal sanitary condition.
Various techniques and procedures have been developed to clean the water-handling system of whirlpool bath systems. For example, the tub basin can be filled with water and an appropriate cleaning agent added to the water (typically a detergent, deodorant, and/or disinfectant) and the tub system operated in the usual manner to circulate the cleaning agent. After the cleaning cycle is completed, the tub is drained in the usual manner. The tub basin is thereafter refilled with clean rinse water that is recirculated to rinse the cleaning agent from the water conduits. In some cases, a second rinse cycle is indicated. After the rinse water is drained from the tub basin, the surfaces of the tub are typically wiped clean. This cleaning technique is generally effective, although tub basins that are relatively large require a correspondingly large volume of the cleaning agent to achieve an effective concentration in the circulated water. Additionally, the requirement for one or more rinse cycles results in a large volume of water being used. The time required to effect cleaning, including the final wipe-down of the tub surfaces, results in labor costs that may be inconsistent with commercial whirlpool tub applications.
Other approaches have been developed to provide closed-loop recirculation through the water conduits. For example, U.S. Pat. No. 4,979,245 entitled "Self-Cleaning Whirlpool System for Bathtubs in General" discloses a representative closed-loop system in which a bypass conduit is provided to effectively isolate the water-carrying components from the tub basin. The recirculation pump is then operated to recirculate a cleaning agent within the water path. While such closed-loop recirculation systems tend to be effective, they are also complex and expensive to install.

Pressurized flow self-cleaning whirlpool tub system


Provided is a method of fabricating a semiconductor device. The method includes forming an anti-reflection layer on a lower layer, forming photoresist patterns on the anti-reflection layer, forming protection patterns to cover the photoresist patterns, respectively, etching the anti-reflection layer using the photoresist patterns covered with the protection patterns as an etch mask to form anti-reflection patterns, forming spacers to cover sidewalls of the anti-reflection patterns, and removing the anti-reflection patterns.

Example embodiments of the inventive concepts relate to a method of fabricating a semiconductor device, and in particular, to a method of fabricating a semiconductor device using a double patterning technology.
In order to realize a highly-integrated semiconductor device, it is necessary to have a method of forming fine patterns. For example, to integrate more and more devices per a given area, a size of each pattern should be as small as possible. In other words, patterns should be formed in such a way that a pitch thereof is reduced. Due to the recent drastic reduction in the design rule of the semiconductor device, it becomes more and more difficult to form fine patterns with a desired small pitch by only using a photolithography technology with a specific resolution limitation.

Method of forming fine patterns in an anti-reflection layer for use as a patterning hard mask


A traffic supervisory method for supervising a group of packets generated in a terminal according to an assigned traffic characteristic in which the maximum number of packets generated within a regular period time T is set at N comprises respectively counting the number of packets which are generated within regular time periods .alpha.i.multidot.T ({.alpha.i.vertline.1.ltoreq.i.ltoreq.M, 1.ltoreq..alpha.1<.alpha.2<. . . <.alpha..sub.M }) in a packet flow and judging the packets to violate the assigned traffic characteristic in the case where more packets are generated than .alpha.i.multidot.(1+.beta.i).multidot.N({.beta.i.vertline.1.ltoreq.i.ltor eq.M, .beta.1.gtoreq..beta.2> . . . >.beta..sub.M =0}) within at least one regular interval of time .alpha.i.multidot.T.

1. Field of the Invention
The present invention relates to a traffic supervisory method for supervising packets to determine whether or not the packets violate a traffic characteristic in a packet switching method or an asynchronous transfer mode (ATM) switching method and a traffic supervisory apparatus for performing the method.
2. Description of Background
Generally, for example, in a packet switched network in which virtual channels are set up among terminals and a regular transmission quality is guaranteed, a call set up control is required to set up the virtual channels. The call set up control is performed for guaranteeing a regular transmission quality of a virtual channel by predicting a certain transmission quality decided by allocating the virtual channel to a terminal when a call set up request occurs and rejecting the call set up request when the predicted transmission quality is inferior to a required transmission quality.
The prediction of the transmission quality is performed according to each traffic characteristic of a virtual channel. For example, the prediction is performed by utilizing one specific value declared as the traffic characteristic by the terminal or utilizing another specific value registered in advance as the traffic characteristic.
A traffic characteristic is defined as a peak rate of generated packets, an average rate, a burst property, and the like. In particular, a method has been proposed to provide the traffic characteristic by utilizing a regular period time T and the maximum number N of packets generated within the regular period time T.
However, even if a call set up is performed by a call set up control, a requested transmission quality is not satisfied in practice when a packet violating the declared traffic characteristic is generated in a call during an actual communication. Therefore, each packet must be supervised to determine whether or not the packet generated at one virtual channel violates the traffic characteristic utilized for the set up control, to reject a violating packet when the violation occurs, and to avoid extending an adverse influence to the transmission quality of the other virtual channels.
Also, the generation of the packets in each terminal must be controlled to generate the packets according to the declared traffic characteristic.
Therefore, a conventional traffic supervisory method has been proposed as follows. In the method, the traffic characteristic is provided by utilizing a regular period time T and the maximum number N of packets generated within the regular period time T as mentioned above. Then, the number of packets generated within the regular period time T is measured and the packets generated beyond N in number are judged to violate the traffic characteristic so that the violating packets are rejected.
However, when the traffic characteristic is supervised by utilizing the above method, a drawback is, for example, produced in the generation of the packets shown in FIG. 1
FIG. 1 shows the highest degree of traffic deviation in the conventional art.
As shown in FIG. 1, in the case where a group of packets (N in number) is intensively generated at a peak rate N/T.sub.0 at the latter period T.sub.0 of a first regular period time T and another group of packets (N in number) is also intensively generated at a peak rate N/T.sub.0 at the first period T.sub.0 of a second regular period time T, a group of packets exceeding N in number is detected between a first measuring time t1 and a second measuring time t2 when a starting point t3 of the terminal cycle at which the terminal generates the packets differs from another starting point t1 of the supervising cycle in a packet switched network.
Therefore, even if a group of packets (N in number) is generated in a terminal in one cycle according to a traffic characteristic which is assigned to the terminal, in the packet switched network it is determined whether more packets have been generated than a predetermined value N. That is, the packets are judged to violate the assigned traffic characteristic.
To avoid the above judgement, the coincidence of two types of cycles must be guaranteed. One type of cycle is utilized at the terminals and another type of cycle is utilized in the switched network. However, it is not easy to control both cycles.
Also, whenever a plurality of terminals connected with a multiplexed line through a multiplexing device to efficiently utilize a subscriber's line and many packets which are respectively transmitted through corresponding virtual channels arrive at a multiplexing device to be multiplexed, statistical fluctuation is generated at the time intervals determined by the multiplexed packets.
In detail, as shown in FIG. 2, because a group of packets A is multiplexed with another group of packets B in order of the generation, time intervals T1, T2 between packets are for example changed to time intervals T1', T2'. Therefore, even if the packets A are generated at a terminal A according to the assigned traffic characteristic, the packets A are shifted in the multiplexing device so that the assigned traffic characteristic is not satisfied at the outlet of the multiplexing device.
Therefore, when the traffic supervision is performed, it is judged that the packets violate the assigned traffic characteristic even if the packets are generated in the terminal according to the assigned traffic characteristic.
Moreover, when a single virtual channel in a subscriber's loop is utilized for communication, the packets generated by an end user are provided to the multiplexing device. Therefore, the peak rate in the virtual channel can be supervised.
However, the end users sometimes communicate with each other by multiplexing a plurality of virtual channels to the single subscriber's loop by utilizing a private branch exchange (PBX) to efficiently utilize the subscriber's loop. In this case, it is impossible to avoid the statistical fluctuation at the arrival intervals of the packets generated by the multiplexing process without utilizing a specific multiplexing method by assigning a regular time slot to each virtual channel.
Therefore, even if the packets are generated in each virtual channel according to a predetermined peak rate, the arrival interval of the packets is sometimes shortened less than the minimum interval decided by the predetermined peak rate in the peak rate supervisory location of the multiplexing device. For the above reason, in the conventional peak rate supervisory method, the packets generated in the terminal according to the assigned traffic characteristic are judged to violate the assigned traffic characteristic.

Traffic supervisory method and traffic supervisory apparatus


The present invention provides multivalent vaccines for the treatment of B-cell malignancies (e.g., lymphomas and leukemias). The present invention also provides methods for the production of custom vaccines, including multivalent vaccines for the treatment of immune cell tumors malignancies as well as methods of treating immune cell tumors using custom vaccines.

As an increasing number of genes are isolated and developed for the expression of a wide array of useful polypeptide drugs, there is an increasing need to enhance the efficiencies and economies of the process. It is advantageous to obtain such polypeptides from mammalian cells since such polypeptides or proteins are generally correctly folded, appropriately modified and completely functional, often in marked contrast to those proteins as expressed in bacterial cells.
When large amounts of product are required, it is necessary to identify cell clones in which the vector sequences are maintained (i.e., retained) during cell proliferation. Such stable vector maintenance can be achieved either as a consequence of integration of the vector into the DNA of the host cell or by use of a viral replicon such as bovine papillomavirus (BPV).
The use of viral vectors such as BPV-based vectors for the generation of stable cell lines expressing large amounts of a recombinant protein has been successful in some cases; however, the use of viral vectors is limited by the fact that the viral vectors are restricted in the cell types in which they can replicate. Furthermore expression levels and episomal maintenance of the viral vector can be influenced by the DNA sequences inserted into the vector.
Where the vector has been integrated into the genomic DNA of the host cell to improve stability, the copy number of the vector DNA, and concomitantly the amount of product which could be expressed, can be increased by selecting for cell lines in which the vector sequences have been amplified after integration into the DNA of the host cell.
A known method for carrying out such a selection procedure is to transform a host cell with a vector comprising a DNA sequence which encodes an enzyme which is inhibited by a known drug. The vector may also comprise a DNA sequence which encodes a desired protein. Alternatively the host cell may be co-transformed with a second vector which comprises the DNA sequence which encodes the desired protein.
The transformed or co-transformed host cells are then cultured in increasing concentrations of the known drug hereby selecting drug-resistant cells. It has been found that one common mechanism leading to the appearance of mutant cells which can survive in the increased concentrations of the otherwise toxic drug is the over-production of the enzyme which is inhibited by the drug. This most commonly results from increased levels of its particular MRNA, which in turn is frequently caused by amplification of vector DNA and hence gene copies.
It has also been found that when drug resistance is caused by an increase in copy number of the vector DNA encoding the inhibitable enzyme, there is a concomitant increase in the copy number of the vector DNA encoding the desired protein in the DNA of the host cell. There is thus an increased level of production of the desired protein.
The most commonly used system for such co-amplification uses dihydrofolate reductase (DHFR) as the inhibitable enzyme. This enzyme can be inhibited by the drug methotrexate (MTX). To achieve co-amplification, a host cell which lacks an active gene which encodes DHFR is either transformed with a vector which comprises DNA sequences encoding DHFR and a desired protein or co-transformed with a vector comprising a DNA sequence encoding DHFR and a vector comprising a DNA sequence encoding the desired protein. The transformed or co-transformed host cells are cultured in media containing increasing levels of MTX, and those cell lines which survive are selected.
The co-amplification systems which are presently available suffer from a number of disadvantages. For instance, it is generally necessary to use a host cell which lacks an active gene encoding the enzyme which can be inhibited. This tends to limit the number of cell lines which can be used with any particular co-amplification system.
For instance, there are at present, only two cell lines known which lack the gene encoding DHFR and both of these cell lines are derivatives of the CHO-K1 cell line. These DHFR.sup.- CHO cell lines cannot be used to express certain protein products at high levels because CHO cells lack specialized postranslational modification pathways. For example, the production of functional human protein C requires that the cell possess the vitamin K-dependent y-carboxylation pathway; CHO cells cannot properly modify the human protein C protein [Walls et al., (1989) Gene 81:139].
Attempts to use DHFR genes as dominant selectable markers in other cell lines (i.e., cell lines synthesizing wild type levels of DHFR) has not proved satisfactory. For instance, a MTX-resistant mutant DHFR or a DHFR gene under the control of a very strong promoter can act as a dominant selectable marker in certain cell types but such high concentrations of MTX are required that it has not been possible to achieve high copy numbers by selection for gene amplification using current methodologies.
Another approach to allow the use of DHFR as a dominant selectable marker in DHFR.sup.+ cell lines is the use of both the DHFR gene and a gene encoding a selectable marker, such as the hygromycin phosphotransferase (hyg) gene, in addition to the gene of interest [Walls, et al. (1989), supra]. This approach is used to circumvent the problem of amplification of the endogenous dhfr gene during selection with MTX. The cells are transfected with DNA encoding the three genes and the cells are first selected for their ability to grow in hygromycin. The cells are then selected for the ability to grow in increasing concentrations of MTX. While this approach allows for the co-amplification of genes in dhfr.sup.+ cell lines, present protocols show that the dhfr gene is amplified to a higher degree than the gene of interest with successive rounds of amplification (i.e., stepwise increases in MTX concentration). For example, in several amplified clones the dhfr gene was present at approximately 100 copies while the gene of interest was present at only 20 copies.
Clearly, the art needs improved methods which would consistently provide for the coincidental amplification of the amplifiable marker and the gene of interest in a variety of cell lines. Furthermore, the art needs a means of amplfying DNA sequences of interest which is efficient, reproducible and which is not limited to the use of specialized enzyme deficient host cell lines or to a limited number of cell lines.
Improved methods which consistently provide for the coincidental amplification of the amplifiable marker and the gene of interest in a variety of cell lines and which are efficient and reproducible would allow the production of custom tumor-specific vaccines on a scale commensurate with patient demand. Current methods for producing custom tumor vaccines for the treatment of B-cell lymphoma are insufficient to meet current and anticipated future demand.

Vaccines for treatment of lymphoma and leukemia


A sense amplifier circuit for use in a ROM comprises, an excess charge detecting circuit for producing a detection output when a potential of a bit line exceeds a normal value, and an excess charge discharging circuit which operates in response to said excess charge detecting circuit for discharging a bit line charge and for returning the bit line potential to the normal value.. The excess charge detecting circuit and the excess charge discharge circuit can be realized by a diode connected transistor connected between the bit line and an inverter of the sense amplifier. When the bit line potential is about to exceed the predetermined value, the transistor turns on to prevent the bit line potential from exceeding the predetermined value.

The present invention relates to a sense amplifier circuit for a reading circuit of a semiconductor memory apparatus, and more particularly to a sense amplifier circuit for a read only memory.
Recent non-volatile memories such as read-only memories (called ROM hereinafter) are required to have large capacity and to operate at high speed. In order to realize a large memory capacity, the memory cell area must be decreased, even if this requires that the current-driving ability of the memory cell transistor be decreased. Thus, it is necessary to develop a sense amplifier which operates at a small cell current.
A ROM is formed as shown in FIG. 1. 10 is a memory cell array comprising a plurality of word lines WL and bit lines BL, and a memory cell 10a provided at respective crossing portions of these word lines WL and bit lines BL. Memory cell 10a comprises, for example, a MOS transistor whose gate is connected to word line WL and whose drain is connected to bit line BL. Memory cell 10a may comprise a bipolar transistor. Word lines WL are selected by row decoder 11 and bit lines BL are selected by column decoder 12, and an address signal is input to these row and column decoders through address buffer 13. The read output of a bit line BL selected by the column decoder 12 is amplified by sense amplifier 14 and is outputted externally through output buffer 15.
That portion designated as sense amplifier 14, comprising a serial connection of load 21, transistor Q.sub.1 and memory cell 20, as shown in FIG. 2, is connected between power source V.sub.CC and ground GND. A potential at the crossing point of load 21 and transistor Q.sub.1 is detected by voltage output circuit 22. The source potential v.sub.a of transistor Q.sub.1 is inverted by inverter 23 and applied to a gate of transistor Q.sub.1. Memory cell 20 comprises a plurality of memory cells 20a, 20b . . . as shown in FIGS. 3A and 3B. FIG. 3A designates a serial type memory cell and FIG. 3B designates a parallel type memory cell. In a serial type memory, memory cells 20a, 20b . . ., which are formed of transistors, store either "1" or "0" depending on whether the transistor is of an enhancement type or of a depletion type. In a parallel type memory, "1" or "0" is stored depending on whether the threshold value is high or low.
In the configuration of FIG. 3A, the non-selection word line is made to level H and the selection word line is made to level L. When the word line WLb is selected, other word lines WLa, WLc, . . . are at H level and transistors 20a, 20c . . . are on regardless of whether the stored value is "1" or "0". Only transistor 20b, belonging to the selected word line, is turned on and off, depending on whether 1 or 0 is stored. If transistor 20b is of the depletion type it is on and if it is of the enhancement type it is off. Accordingly, depending on whether memory cell 20b is of the depletion type or the enhancement type, the data stored in memory cell 20b is determined to be 1 or 0, and thus a current flows or does not flow in bit line BLa. The potential V.sub.C at the connecting point between load 21 and transistor Q.sub.1 in FIG. 2 changes depending on whether or not the bit line current (i.sub.cel) flows and voltage output circuit 22 detects potential V.sub.C and produces read out data.
In the configuration of FIG. 3B, the selected word line is at H level and the non-selected word line is at L level. Accordingly, memory cells belonging to non-selected word lines are turned off regardless of whether "1" or "0" is stored, and only the memory cell belonging to the selected word line is turned on or off depending on whether "1" or "0" is stored. A current flows or does not flow in bit line BLa, depending on whether the memory cell is turned on or off, thereby changing the voltage V.sub.C. Voltage output circuit 22 then detects the voltage V.sub.C and produces the read-out data. Voltage output circuit 22 basically comprises only a line, but may be formed of a circuit for driving an output side circuit to be connected to the sense amplifier.
A column selection gate, which is turned on or off depending on the output of decoder 12, is provided between transistor Q.sub.1 and the bit line (cell group).
By making the slope of the input-output characteristic abrupt when inverter 23 in a transient state, the variation of the bit line voltage v.sub.a is suppressed, whether the bit line current I.sub.CEL is turned on or off. As shown in FIG. 5, when the cell is on, i.e., when the bit-line current flows, the voltage v.sub.a decreases, but the output v.sub.b of inverter 23 increases. When the cell is off, the voltage V.sub.a increases but the output V.sub.b of inverter 23 decreases quickly, thus decreasing the width of the variation of the voltage v.sub.a. This is effective for high speed operation. The voltage V.sub.C is equal to V.sub.CC -Rx.sub.icel under the condition that the resistance of load 21 is R and changes as shown in the drawing, depending on whether the cell is switched on or off.
Various kinds of inverters 23 are shown in FIGS. 4A to 4H. FIG. 4A shows an E-D type, FIG. 4B an E--E type, FIG. 4C and FIG. 4D CMOS types in which Qa is an n-channel enhancement type MOS transistor, Qb is an n-channel depletion type MOS transistor and Qd is a p-channel type MOS transistor. FIGS. 4E to 4H show only load portions. The gate of p-channel type transistor Qd is connected to ground in FIGS. 4C and 4G, connected to input IN in FIG. 4D and connected to the drain (output OUT) in FIG. 4H. The input-output characteristic of inverter 23 is shown in FIG. 6. When the input voltage v.sub.a is L (low), the output voltage v.sub.b is H (high), and when the input voltage v.sub.a is H (high), the output voltage v.sub.b is L (low). The input and the output characteristic changes proportionally between the above two states, as shown in FIG. 6. The variation width .DELTA.v.sub.a of the voltage v.sub.a in FIG. 6 is obtained from this proportionate area. Thus, the variation .DELTA.v.sub.b, which is expanded from the variation width .DELTA.v.sub.a, can be obtained. The boundary at which the transistor Q.sub.1 is turned on/off, is determined from v.sub.b -v.sub.a =V.sub.th1, assuming that V.sub.th1 is the threshold voltage of the transistor. P1 is a balance point at which the cell is turned off and P2 is the balance point when the cell is tuned on. The variation of voltage v.sub.a is small, as shown in FIG. 6.
For multi-value logic, the current is divided into several steps and for binary-value logic, the two states, i.e., the state in which current flows and the state in which current does not flow, are provided. Let us explain the example of two steps in which the current flows or does not flow.
As described above, the output of inverter 23 is fed back to the input of inverter 23 through transistor Q.sub.1. Moreover, the input-output characteristic of the inverter is abrupt. Therefore, the range of variation of v.sub.a can be made small, and v.sub.b can be changed quickly. That is, the variation of V.sub.a is made small so that the existence of a bit line capacitance shown in FIG. 7 does not greatly affect the operation of the cell 20, and the range of the variation in v.sub.b is made large, thus enabling the on/off control of transistor Q.sub.1 to be conducted at high speed and with certainty. When the memory cell is changed from a state in which current flows to a state in which current does not flow, the current stops flowing when v.sub.b -v.sub.a is equal to the V.sub.th of Q.sub.1 (at point P1). When a current flows in the memory cell, a charging operation of the bit line capacitance 24 is conducted and then completed. Thus, a current flowing through the bit line capacitance of the bit line is made 0. Thus, v.sub.b -v.sub.a changes until the current flowing into transistor Q.sub.1 becomes equal to the cell current (P.sub.2).
A column selection gate shown in FIG. 7 is connected between a cell 20 and a sense amplifier comprising transistor Q.sub.1, inverter 23 and load 21 and has a relatively large capacitance. As shown in FIG. 8, a parasitic capacitance C.sub.WB exists between bit line BL and word line WL. C.sub.BL is a parasitic capacitance existing between bit line BL and ground. The bit line potential is almost equal to v.sub.a. Thus, a change in v.sub.a means that the bit line potential changes and that the charges stored in bit line capacitances C.sub.BL and C.sub.WB change accordingly. When a current flows in the cell 20, the cell 20 has caused a discharge current of the bit line capacitance to flow, in addition to a sense current. The current flowing in the cell 20 and the sensed current differ in accordance with the amount of the discharge current. This is a factor contributing to access delay.
The fact that the change in v.sub.a is small means that the change in bit line potential is small and thus that the change in charge stored in the bit line is small, thereby decreasing the delay in access speed caused by the discharge current and providing an advantage of increased operation speed.
However, when the bit line potential exceeds that required for normal operation, the sense amplifier operates only after the excess charge is discharged by the cell transistor.
The reason for the above operation is that a variation in word line potential is reflected on a bit line by a parasitic capacitance C.sub.WB between a word line and a bit line and that an operation point of a sense amplifier varies in accordance with a power source potential variation caused by a noise.
Excess charge-up due to the power source voltage variation is explained by referring to FIGS. 9 and 10. The power source voltage is changed from an ordinary state (state A in FIG. 9) of a cell off-state at the power source voltage V.sub.CC to a state at power source voltage V.sub.CC +.DELTA.V. The input voltage v.sub.a of inverter 23 is detected under a new power source voltage V.sub.cc +.DELTA.V as if it would apparently decrease, thereby increasing v.sub.b (state B in FIG. 9, a.fwdarw.b in FIG. 10). As a result, current flows through transistor Q.sub.1 and the bit line capacitance is charged up. As a result, v.sub.a increases and v.sub.b decreases, thereby providing a new stable state under the voltage V.sub.CC +.DELTA.V (state C, b.fwdarw.c). When the source voltage is returned from this state to V.sub.CC, it is detected as if v.sub.a had increased and v.sub.b had decreased (state D, c.fwdarw.d). However, even if v.sub.b decreases by a large amount, transistor Q.sub.1 only turns off at a voltage of less than v.sub.b -v.sub.a =V.sub.th1 and the current supply is cut off. Therefore, v.sub.a maintains the present potential by means of a bit line capacitance (as shown by a dashed line in state E, d). When the state of the cell changes from OFF to ON as a result of an address selection by an addres signal ADDRESS, the excess charge is discharged through a cell transistor. The potential of v.sub.a decreases and the potential of v.sub.b increases (as shown by a dashed line in state F', d.fwdarw.a). After excess charge is discharged, until v.sub.b -v.sub.a >V.sub.th1, an ordinary sense operation is carried out (state G, a.fwdarw.e). In the conventional current driving capability of a cell transistor, a time delay or a surplus time period shown in a state F' and d.fwdarw.a time delay is relatively unimportant, but when the current driving capability of the cell, i.e., the current driving capability by which the input-output characteristic is driven from d to e, becomes weak because of a fine pattern of the cell, the time delay in this surplus time period F' becomes large, greatly affecting access time.


A device includes a transmitter, at least one temperature sensor; and a controller. The controller is responsive to the at least one temperature sensor indicating that a temperature has risen above a first threshold to control the transmitter to reduce transmit power from a first power level to a second power level, wherein the second power level is a non-zero power level.

It is well known to attach modules to laptop or notebook computers to provide additional functionality thereto. Examples include Wi-Fi (IEEE 802.11) and 3G data card modules which connect to a laptop via a PCMCIA (Personal Computer Memory Card International Association) interface. It is known also to provide a Wi-Fi module as an ExpressCard, which is a form of PCI-Express device. Wi-Fi and 3G data modules also can be connected by USB (Universal Serial Bus) interface to a laptop computer.
Such modules can be external or internal. A module is powered by electrical power provided over the interface by which it is connected to the laptop computer. The main components of a module are a transceiver, a processor (which provides a control function as well as a processing function), buffer memory and an antenna connector. An antenna within the laptop can be connected to the module via the antenna connector. The presence of the processor and the memory results in operation of the modules being dependent on the ambient temperature falling within an acceptable range.
It is known to provide a module with a temperature sensor by which it can be detected whether the temperature of the module is above the upper limit of the acceptable range and thus close down the module's transmitter.

Temperature-dependent power adjustment of transmitter


Two Mach-Zehnder optical interferometer circuits are accurately point-symmetrically connected to each other to form a first point-symmetrically connected optical interferometer circuit constituting a light input side circuit. Optical signals having a plurality of wavelengths are input to a light input terminal. A second point-symmetrically connected optical interferometer circuit having the same functional structure as the first point-symmetrically connected optical interferometer circuit is connected to a through port, which is an output terminal of the light input side circuit, as a first light output side circuit. A cross port, which is the other output terminal of the light input side circuit, is connected to a second light output side circuit having at least one of Mach-Zehnder optical interferometer circuits whose transmittance characteristics are different from those of the Mach-Zehnder optical interferometer circuits.

In recent years, an Internet has been popularized in home, and high-speed and cheap communication services, in which a constant connection has been made by ADSL or FTTH, of which a transmission speed is several Mbps, and of which a monthly subscription is several tens of dollars, have been provided. Further, with the spread of broadband communication, a large amount of contents have been distributed, and a video chat has come into wide use.
With the spread of broadband communication, a B-PON system capable of providing high-speed data communication having a data transmission speed of 100 Mbps at a peak time and of simultaneously distributing multi-channel (for example, a maximum of 500 channels) image signals using one optical fiber has been used as an international standard of ITU-T. The structure of this system is shown in FIG. 26 (for example, see an outline of the B-PON system described in the home page of an NTT-AS institute).
Further, in FIG. 26, a communication station 40 is connected to a user home 41 through a communication optical fiber 45. In FIG. 26, B-ONU indicates a data-based subscriber station apparatus for data, WDM indicates an optical coupler, V-ONU indicates an image-based subscriber station apparatus, NE-OSS indicates a data-based monitor control apparatus, B-OLT indicates a data-based service station apparatus, EMDX indicates an Ether demultiplexing apparatus, and V-OLT indicates an image-based service station apparatus.
The salient characteristic of this system is that one optical wavelength is added to two wavelengths used for the transmission and reception of high-speed data by an additional optical wavelength arrangement and thus the distributed multi-channel images can be simultaneously seen. In general, wavelengths of high-speed data communication signals to be transmitted and received are included in a wavelength band of 1.49 μm (1.48 μm to 1.50 μm) or a wavelength band of 1.31 μm (1.26 μm to 1.36 μm), and an image is distributed at a wavelength band of 1.55 μm (1.55 μm to 1.56 μm), which is an amplifying band of EDFA.
Since optical signals having three types of wavelengths are transmitted through one optical fiber, the B-PON system requires a wavelength multiplexing and demultiplexing function having an optical signal multiplexing and demultiplexing function (the multiplexing and demultiplexing of optical signals having a plurality of wavelengths) and a function of distributing image signals with the same intensity. Conventionally, a dielectric multi-layer filter has been used as an optical component having the wavelength multiplexing and demultiplexing function. An optical component having the wavelength multiplexing and demultiplexing function requires a broadband wavelength multiplexing and demultiplexing characteristic and a high-isolation characteristic greater than, for example, 25 dB, and a development of such a broadband wavelength multiplexing and demultiplexing filter is demanded.
Further, since optical signals having three types of wavelengths are transmitted through one optical fiber, the B-PON system requires an optical signal multiplexing and demultiplexing device having an optical signal multiplexing and demultiplexing function (the multiplexing and demultiplexing of optical signals having a plurality of wavelengths) and an optical splitter for splitting image signals at the same intensity.
Accordingly, an object of the present invention is to provide a broadband wavelength multiplexing and demultiplexing filters improved for or capable of meeting the above-mentioned requirements. In addition, another object of the present invention is to provide an optical splitter with an optical signal multiplexing and demultiplexing function, which is suitable for a B-PON system, etc.

Broadband wavelength multiplexing and demultiplexing filter and optical splitter with optical signal multiplexing and demultiplexing function


This invention generally relates to display driver circuits for electro-optic displays, and more particularly relates to circuits and methods for reducing the re-emission of absorbed light, for example to increase the color gamut of organic light emitting diode displays. A driver for a display comprising a plurality of light emitting diode display elements, the driver comprising addressing circuitry to address said display elements, a first driver to cooperate with said address circuitry to provide a forward drive to at least one of said display elements to illuminate the display element, and a second driver to provide a reverse bias drive to others of said display elements at the same time as said at least one display element is illuminated to reduce a level of photoluminescence from said others of said display elements.

1. Field of the Invention
This invention generally relates to display driver circuits for electro-optic displays, and more particularly relates to circuits and methods for reducing the re-emission of absorbed light, for example to increase the colour gamut of organic light emitting diode displays.
2. Related Technology
Organic light emitting diodes (OLEDs) comprise a particularly advantageous form of electro-optic display. They are bright, colourful, fast-switching, provide a wide viewing angle and are easy and cheap to fabricate on a variety of substrates. Organic LEDs may be fabricated using either polymer or small molecules in a range of colours (or in multi-coloured displays), depending upon the materials used. Examples of polymer-based organic LEDs are described in WO 90/13148, WO 95/06400 and WO 99/48160; examples of so called small molecule based devices are described in U.S. Pat. No. 4,539,507.
A base structure 100 of a typical organic LED is shown in FIG. 1a. A glass or plastic substrate 102 supports a transparent anode layer 104 comprising, for example, indium tin oxide (ITO) on which is deposited a hole transport layer 106, an electroluminescent layer 108, and a cathode 110. The electroluminescent layer 108 may comprise, for example, a PPV (poly(p-phenylenevinylene)) and the hole transport layer 106, which helps match the hole energy levels of the anode layer 104 and electroluminescent layer 108, may comprise, for example, PEDOT:PSS (polystyrene-sulphonate-dope polyethylene-dioxythiopene). Cathode layer 110 typically comprises a low work function metal such as calcium and may included an additional layer immediately adjacent electroluminescent layer 108, such as a layer of aluminum, for improved electron energy level matching. Contact wires 114 and 116 and to the anode the cathode respectively provide a connection to a power source 118. The same base structure may also be employed for small molecule devices.
Other examples of materials which may be employed for layer 108 include poly(2-methoxy-5-(2′-ethyl)hexloxyphenylene-vinylene)("MEH-PPV"), a PPV derivative (e.g. a di-alkoxy or di-alkyl derivative), a polyfluorene and/or a co-polymer incorporating polyfluorene segments, PPVs and/or related co-polymers, poly(2,7-(9,9-di-n-octyfluorene)-(1,4-phenylene-((4-secbutylphenyl)imino)-1,4-phenylene)) ("TFB"), ("PFB") poly(2,7-(9,9-di-n-octyfluorene)-(1,4-phenylene-((4-methylphenyl)imino)-1,4-phenylene-((4-methylphenyl)imino)-1,4-phenylene))("PFM"), poly(2,7-(9,9-di-n-octyfluorene)-(1,4-phenylene-((4-methoxyphenyl)imino)-1,4-phenylene-((4-methoxyphenyl)imino-1,4-phenylene)) ("PFMO"), poly(2,7-(9,9-di-n-octyfluorene) ("F8") or poly (2,7-(9,9-di-n-octyfluorene)-3,6-Benzothiadiazole) ("F8BT"). Alternatively a so-called small molecule such as tris-(8-hydroxyquinoline aluminum)("Alq3") as described in U.S. Pat. No. 4,539,507, may be employed.
In the example shown in FIG. 1a light 120 is emitted through transparent anode 104 and substrate 102 and such devices are referred to as "bottom emitters". Devices which emit through the cathode may also be constructed, for by keeping the thickness of cathode layer 110 less than around 50-100 nm so that the cathode is substantially transparent.
Organic LEDs may be deposited on a substrate in a matrix of pixels to form a single or multi-colour pixelated display. A multicoloured display may be constructed using groups of red, green, and blue emitting pixels. In such displays the individual elements are generally addressed by activating row (or column) lines to select the pixels, and rows (or columns) of pixels are written to, to create a display. So-called active matrix displays have a memory element, typically a storage capacitor and a transistor, associated with each pixel whilst passive matrix displays have no such memory element and instead are repetitively scanned, somewhat similarly to a TV picture, to give the impression of a steady image.
FIG. 1b shows a cross section through a passive matrix OLED display 150 in which like elements to those of FIG. 1a are indicated by like reference numerals. In the passive matrix display 150 the electroluminescent layer 108 comprises a plurality of pixels 152 and the cathode layer 110 comprises a plurality of mutually electrically insulated conductive lines 154, running into the page in FIG. 1b, each with an associated contact 156. Likewise the ITO anode layer 104 also comprises a plurality of anode lines 158, of which only one is shown in FIG. 1b, running at right angles to the cathode lines. Contacts (not shown in FIG. 1b) are also provided for each anode line. An electroluminescent pixel 152 at the intersection of a cathode line and anode line may be addressed by applying a voltage between the relevant anode and cathode lines.
Referring now to FIG. 2a, this shows, conceptually, a driving arrangement for a passive matrix OLED display 150 of the type shown in FIG. 1b, A plurality of constant current generators 200 are provided, each connected to a supply line 202 and to one of a plurality of column lines 204, of which for clarity only one is shown. A plurality of row lines 206 (of which only one is shown) is also provided and each of these may be selectively connected to a ground line 208 by a switched connection 210. As shown, with a positive supply voltage on line 202, column line; 204 comprise anode connections 158 and row lines 206 comprise cathode connections 154, although the connections would be reversed if the power supply line 202 was negative and with respect to ground line 208.
As illustrated pixel 212 of the display has power applied to it and is therefore illuminated. To create an image connection 210 for a row is maintained as each of the column lines is activated in turn until the complete row has been addressed, and then the next row is selected and the process repeated. Alternatively a row may be selected and an the column written in parallel, that is a row selected and a current driven onto each of the column lines simultaneously, to simultaneously illuminate each pixel in a row at its desired brightness. Although this latter arrangement requires more column drive circuitry it is preferred because it allows a more rapid refresh of each pixel. In a further alternative arrangement each pixel in a column may be addressed in turn before the next column is addressed, although this is not preferred because of the effect, inter alia, of column capacitance as discussed below. It will be appreciated that in the arrangement of FIG. 2a the functions of the column driver circuitry and row driver circuitry may be exchanged.
It is usual to provide a current-controlled rather than a voltage-controlled drive to an OLED because the brightness of an OLED is determined by the current flowing through it, this determining the number of photons it outputs in a voltage-controlled configuration the brightness can vary across the area of a display and with time, temperature, and age, making it difficult to predict how bright a pixel will appear when driven by a given voltage. In a colour display the accuracy of colour representations may also be affected.
FIGS. 2b to 2d illustrate, respectively, the current drive 220 applied to a pixel, the voltage 222 across the pixel, and the light output 224 from the pixel over time 226 as the pixel is address. The row containing the pixel is addressed and at the time indicated by dashed line 228 the current is driven onto the column line for the pixel. The column line (and pixel) has an associated capacitance and thus the voltage gradually rises to a maximum 230. The pixel does not begin to emit light until a point 232 is reached where the voltage across the pixel is greater than the OLED diode voltage drop. Similarly when the drive current is turned off at time 234 the voltage and light output gradually decay as the column capacitance discharges. Where the pixels in a row are all written simultaneously, that is where the columns are driven in parallel, the time interval between times 228 and 234 corresponds to a line scan period.
It is desirable to be able to provide a grayscale-type display, that is one in which the apparent brightness of individual pixels may be varied rather than simply set either on or off. In the context of this invention "grayscale" refers to such a variable brightness display, whether a pixel is white or coloured.
The conventional method of varying pixel brightness is to vary pixel on-time using Pulse Width Modulation (PWM). In the context of FIG. 2b above the apparent pixel brightness may be varied by varying the percentage of the interval between times 228 and 234 for which drive current is applied. In a PWM scheme a pixel is either full on or completely off but the apparent brightness of a pixel varies because of integration within the observer's eye.
Pulse Width Modulation schemes provide a good lines brightness response but to overcome effects related to the delayed pixel turn-on they generally employ a pre-charge current pulse (not shown in FIG. 2b) on the leading edge 236 of the driving current waveform, and sometimes a discharge pulse on the trailing edge 238 of the waveform. As a result, charging (and discharging) the column capacitance can account for half the total power consumption in displays incorporating this type of brightness control. Other significant factors which the applicant has identified as contributing to the power consumption of a display plus driver combination include dissipation within the OLED itself (a function of OLED efficiency), resistive losses in the row and column lines and, importantly in a practical circuit, the effects of a limited current driver compliance, as explained in more detail later.
FIG. 3 shows a schematic diagram 300 of a generic driver circuit for a passive matrix OLED display. The OLED display is indicated by dashed line 302 and comprises a plurality n of row lines 304 each with a corresponding row electrode contact 306 and a plurality m of column lines 308 with a corresponding plurality of column electrode contacts 310. An OLED is connected between each pair of row and column lines with, in the illustrated arrangement, its anode connected to the column line. A y-driver 314 drives the column lines 308 with a constant current and an x-driver 316 drives the row lines 304, selectively connecting the row lines to ground. The y-driver 314 and x-driver 316 are typically both under the control of a processor 318. A power supply 320 provides power to the circuitry and, in particular, to y-driver 314.
FIG. 4 shows a typical active matrix OLED driver circuit 400. A circuit 400 is provided for each pixel of the display and ground 402, Vss 404, row select 414 and column data 416 busbars are provided interconnecting the pixels. Thus each pixel has a power and ground connection and each row of pixels has a common row select line 414 and each column of pixels has a common data line 416.
Each pixel has an organic LED 406 connected in series with a driver transistor 408 between ground and power lines 402 and 404. A connection 409 of driver transistor 408 is coupled to a storage capacitor 410 and a control 412 couples gate 409 to column data line 416 under control of row select line 414. Transistor 412 is a field effect transistor (FET) switch which connects column data line 416 to gate 409 and capacitor 410 when row select line 414 is activated. Thus when switch 412 is on a voltage on column data line 416 can be stored on a capacitor 410. This voltage is retained on the capacitor for at least the frame refresh period because of the relatively high impedances of the gate connection to driver transistor 408 and of switch transistor 412 in its "off" state.
Driver transistor 408 is typically an FET transistor and passes a (drain-source) current which is dependent upon the transistor's gate voltage less a threshold voltage. Thus the voltage at gate node 409 controls the current through OLED 406 and hence the brightness of the OLED.
A voltage-driven active matrix display is described in U.S. Pat. No. 5,684,365 and a current-driven active matrix display is described in WO 99/65012. Other specific examples of OLED display drivers are described in U.S. Pat. No. 6,014,119, U.S. Pat. No. 6,201,520, U.S. Pat. No. 6,332,661, EP 1,079,361A and EP 1,091,339A; OLED display driver integrated circuits are also sold by Clare Micronix of Clare, Inc., Beverly, Mass., USA. The Clare Micronix drivers provide a current controlled drive and achieve grayscaling a conventional PWM approach; U.S. Pat. No. 6,014,119 describes a driver circuit in which pulse width modulation is used to control brightness, U.S. Pat. No. 6,201,520 describes driver circuitry in which each column driver has a constant current generator to provide digital (on/off) pixel control; U.S. Pat. No. 6,332,661 describes pixel driver circuitry it which a reference current generator sets the current output of a constant current driver for a plurality of columns, but this arrangement is not suitable for variable brightness displays; and EP 1,079,361A and EP 1,091,339A both describe similar drivers for organic electroluminescent display elements in which a voltage drive rather than a current drive is employed.
Display technologies based upon inherently emissive devices, unlike, for example, LCDs, tend to have a bright and visually pleasing appearance. There is a continuing need to improve the visual contrast of emissive displays and OLED-based displays in particular, but it is not always clear what effects contribute to contrast reduction. The applicant has recognised that the electroluminescent material normally used in both organic and inorganic light emitting diodes are generally also photoluminescent, and that this photoluminescence can contribute to contrast reduction.
Photoluminescence is a phenomenon in which, broadly speaking, a material absorbs light at one wavelength and re-emits light at a longer wavelength. This photoluminescence can be difficult to observe, even under laboratory conditions, but has the effect of giving a display a less lively appearance, particularly under bright ambient light conditions, and especially outdoors in sunlight. The applicant has found that such contrast-reducing photoluminescence can be stimulated either by absorbed ambient light or by self-absorption particularly, for example, in a display comprising a plurality of pixels, where light from one pixel can cause a neighbouring nominally off pixel to photoluminesce. In a colour display this effect can also cause a colour shift, as described further later.
In more detail, referring to FIGS. 1a and 1b, incident ambient light passes through the substrate 102, transparent anode 104, and hole transport layer 106 to the layer of electroluminescent material 108 where it is absorbed generating excitons, that is bond electron-hole pairs. Alternatively excitons may be generated by light from nearby illuminated pixels propagating through the electroluminescent layer 108, and/or transparent anode layer 104, and/or hole transport layer 106, and/or substrate 102.
With no applied field a significant fraction of these optically excited excitons rapidly radiatively decay emitting light substantially isotropically according to the photoluminescence spectra of the material or materials forming layer 108. The fraction of the excitons decaying radiatively depends upon the photoluminescence efficiency of the material and upon the applied field. When diode formed by the device is in an off state—typically, but not necessarily, when the anode and the cathode are at the same electrical potential—layer 108 is in a quiescent photo-emitting state. Thus when the display is viewed an observer sees a combination of the emitted photoluminescence and reflected and/or scattered light from the display, both of which tend to reduce the display contrast.
Prior art contrast improving techniques have concentrated upon the use of anti-reflection devices, such as filters, the circular polariser described in U.S. Pat. No. 6,211,613 (WO97/38452) assigned to the present applicant, and the black anti-reflection cathode described in U.S. Pat. No. 5,049,780. However these techniques can be insufficient, for example reducing the desired light emission. Moreover these techniques are unable to reduce the level of self-stimulated photoluminescence.
Background prior art relating the improvement of colour purity in electroluminescent display is described in EP 1 087 444, which relates to separate red, green and blue gamma correction, and in EP 1 093 322, which relates to OLED device instruction.
The applicant has recognised that contrast in a light emitting diode-based display, such as a passive or active matrix OLED-based display, may be increased by reducing the contrast-reducing photoluminescence. Where the display comprises light emitting diodes, especially organic LEDs, this photoluminescence may be reduce or quenched by reverse biasing selected ones of the light emitting diodes, that is those LEDs not emitting at any particular moment in time.
The possibility of improving OLED display contrast by reducing or quenching photoluminescence has never previously been recognised. Schemes for applying reverse bias to OLED display are known in the prior art, but these are not intended or suitable for improving contrast by the reduction of photoluminescence. Consequently these prior at reverse biasing schemes exhibit some differences from those described below for contrast-improving photoluminescence reduction.
U. Lemmer et. al., Synthetic Metals, 67 (1994) 169-172 describes the experimental observation of the basic phenomenon of photoluminescence quenching in an ITO/PPV/A1 structure.
WO98/41065 discloses the application of either polarity of driving voltage to an electroluminescent polymer-based display to drive either red light emission from an interface of the polymer or green light emission from the bulk of the polymer.
However, in both cases, the light emitting semiconductor is forward biased (the device effectively comprises two back-to-back diodes).
U.S. Pat. No. 6,201,520 describes the use of reverse biasing for non-selected pixels in a pixilated OLED display to prevent crosstalk which could otherwise be caused by the (electrically) semi-excited state of the non-selected pixels. However U.S. Pat. No. '520 does not specify any particular value of reverse bias drive and does not provide any teaching on the application of a reverse bias drive sufficient to provide an improved contrast display by photoluminescence quenching. Furthermore the mechanism for applying a reverse bias in U.S. Pat. No. '520 limits the reverse bias voltage to the forward bias voltage whereas, generally speaking, it is preferable to apply a larger reverse bias voltage than the forward voltage to achieve adequate photoluminescence reduction for improved contrast.
U.S. Pat. No. 5,965,901, assigned to the present applicant, describes the use of a pulse driving scheme for an organic light-emitting polymer device to improve device lifetime in which positive pulses are separated by negative (reverse bias) pulses. However this document does not contemplate applying reverse bias to some pixels at the same time as applying forward bias to others and is thus unsuitable for reducing photoluminescence stimulated by emission from pixels within the display. Furthermore again the document does not provide any teaching on the application of a reverse bias drive sufficient to provide an improved contrast display by photoluminescence quenching.
EP 1094438A describes the periodic application (for example, every frame) of reverse bias to reduce leakage current due to through-film shorts.

Electroluminiscent display and driver circuit to reduce photoluminesence


A well servicing composition containing an aqueous phase and an oil phase and an ether carboxylic acid of the formula:RO(CH2CH2O)x(CH2CHR1O)yCH2—COOXwherein, R is a saturated or unsaturated, branched or unbranched alkyl or alkenyl group containing 6 to 22 carbon atoms, x is a number from 1 to 20 and y is 0 or a number from 1 to 20, provided that the sum of x and y is at least 1 and at most 25, R1 is an alkyl group containing 1 to 4 carbon atoms and X comprises at least one member selected from the group consisting of a hydrogen atom, monovalent cations and polyvalent cations.

It is known that drilling fluids for sinking wells in rock and bringing up the rock cuttings are flowable water- or oil-based systems that are thickened to a limited extent. Oil-based systems are acquiring increasing significance in practice and are used in particular in offshore drilling operations. Oil-based drilling fluids are generally used as so-called invert emulsion muds which consist of a 3-phase system: oil, water and fine-particle solids. Drilling fluids such as these are preparations of the w/o emulsion type, i.e. the aqueous phase is heterogeneously and finely dispersed in the continuous oil phase. A range of additives may be used for stabilizing the system as a whole and for establishing the required performance properties, including in particular emulsifiers and emulsifier systems, weighting agents, fluid loss additives, viscosity adjusters and optionally an alkali reserve. Further details can be found, for example, in the Article by P. A. Boyd et al., "New base oil used in low toxicity oil muds", Journal of Petroleum Technology, 1985, 137-142.
A key criterion for evaluating the usefulness of invert drilling fluids in practice are their rheological characteristics. Certain viscosity values have to be maintained in drilling fluid systems suitable for practical application. In particular, uncontrolled thickening and hence increases in the viscosity of the drilling fluid have to be strictly prevented because, otherwise, the pipe can become stuck during drilling (cf. Manual of Drilling Fluids Technology, NL Baroid/NL Inc. 1985, Chapter "Stuck Pipe") and can only be freed by expensive, time-consuming measures. In practice, therefore, suitable diluents are added to the drilling fluid systems before and also during drilling. It is known from the prior art that anionic surfactants from the group of fatty alcohol sulfates, fatty alcohol ether sulfates and alkyl benzenesulfonates are preferably used for this purpose. It has been found in practice, however, that although compounds of this type can effectively influence the rheology of the drilling fluids, problems can arise with diluents known from the prior art when drilling fluids are used at low external temperatures. This applies in particular at temperatures of 50° F. (10° C.) and lower. There is invariably an increase in viscosity which is difficult or impossible to control, even when known diluents are used.
In addition, it is important to ensure that the drilling fluid which is pumped into the ground is heated, for example, to temperatures of 150 to 250° F. (66 or 121° C.), depending on the depth, and—in the case of very deep wells—to temperatures of up to 350° F. (178° C.), although it is not always desirable for the rheology of the drilling fluid at high temperatures to be influenced at the same time. Instead, only selective influencing in the critical low temperature range is desirable in many cases.
In addition, all additives and auxiliaries used in offshore and onshore drilling fluid systems are expected to satisfy stringent biodegradability and toxicity requirements. Also, the ambient conditions prevailing during drilling operations, such as high temperatures, high pressures, changes in pH caused by the inrush of acidic gases, etc., impose high demands on the choice of possible components and additives.
If water-based drilling fluid systems in emulsion form are used, as is often the case today, the presence of emulsifiers is essential. A large number of suitable compounds are known to the expert, for example from the disclosure of EP 0 948 577, of which the technical teaching is confined to special temperature-dependent emulsions. However, a large number of emulsifiers suitable for use in drilling fluids are mentioned in that document, cf. the disclosure of paragraphs 0066 to 0076 of EP 0 948 577 B1.
The choice of emulsifiers for well servicing systems and, more particularly, drilling fluids is primarily directed at finding substances which lead to maximum stability of the emulsion, even under the extreme conditions of practical application, i.e. an increase in the viscosity of the drilling fluid and, more particularly, breaking of the emulsion should be strictly prevented. This applies in particular to emulsions of the water-in-oil type.

Borehole treating substance containing ether carboxylic acids


Methods of servicing a wellbore in contact with a subterranean formation include passing an ester-based fluid into the wellbore and reducing a temperature of the ester-based fluid by an amount effective to cause the ester-based fluid to set, e.g., by from about 10° F. to about 20° F. The ester-based fluid includes a water in ester-based oil emulsion, a pH controlling additive, e.g., hydrated lime, in the water-phase, and an emulsifier to stabilize the pH controlling additive. Cooling the ester-based fluid causes the emulsion to destabilize, resulting in the release of the pH controlling additive. This release raises pH of the ester-based fluid by an effective amount to cause it to set. Wellbore servicing fluids comprising the foregoing ester-based fluid may be employed as environmentally friendly sealants or spotting fluids in wellbores.

Natural resources such as gas, oil, and water residing in a subterranean formation or zone are usually recovered by drilling a wellbore down to the subterranean formation while circulating a drilling fluid through the drill pipe and the drill bit and upwardly through the wellbore to the surface. The drilling fluid serves to lubricate the drill bit and carry drill cuttings back to the surface. After the wellbore is drilled to the desired depth, the drill pipe and drill bit are typically withdrawn from the wellbore while the drilling fluid is left in the wellbore to provide hydrostatic pressure on the formation penetrated by the wellbore and thereby prevent formation fluids from flowing into the wellbore.
The next operation in constructing the wellbore usually involves running a string of pipe, e.g., casing, in the wellbore. During this operation, the drilling fluid may remain relatively static in the wellbore for up to 2 weeks, depending on the depth of the wellbore and the difficulty in running the string of pipe in the wellbore. While drilling fluids do not set into hard masses, they do increase in gel strength over time when they are static. As such, the gel strength of the drilling fluid may build up during this period of time. Next, primary cementing is typically performed whereby a cement slurry is pumped down through the string of pipe and into the annulus between the string of pipe and the walls of the wellbore to allow the cement slurry to set into a hard mass (i.e., sheath), and thereby seal the annulus. The cement slurry ideally displaces the drilling fluid from the annulus. However, if the drilling fluid has developed gel strength, portions of the drilling fluid are bypassed by the cement slurry such that areas of the annulus contain drilling fluid rather than the preferable cement slurry. Since the drilling fluid is not settable, complete zonal isolation of the subterranean formation is not achieved, and formation fluids can undesirably flow into and through the wellbore.
To overcome the problems associated with incomplete drilling fluid displacement, so-called settable spotting fluids have been developed to displace drilling fluids from wellbores prior to primary cementing. They have rheological properties to provide for such displacement even if the drilling fluids have relatively high gel strengths. Further, they typically can set over time into a rigid mass having compressive strength, thereby isolating subterranean formations even if the settable spotting fluids are bypassed during primary cementing.
Traditional settable spotting fluids (SSFs) are water-based fluids comprising blast furnace slag, which is the blast furnace by-product formed in the production of cast iron. Such water-based SSFs are incompatible with oil-based drilling fluids and can occasionally cause hole-stability problems or damage to the permeability of producing subterranean formations. Further, the slag-containing SSFs are limited to wellbores having bottomhole static temperatures (BHSTs) of 90° F. or less, i.e., the temperatures at which they slowly set. Further, the slag-containing SSFs prematurely set if they become mixed with cement. To prevent such premature setting, a strong set retarder is typically added to the SSF, and a spacer fluid is commonly inserted between the SSF and the cement slurry.
Oil-based SSFs have been developed that can be used in wellbores drilled with oil-based fluids and that avoid the problems of the water-based SSF's described above. However, such oil-based SSF's contain hydrocarbons that are detrimental to the environment. A need therefore exists for an environmentally friendly SSF that can be used in wellbores having BHSTs greater than 90° F. and that do not prematurely set when exposed to cement.

Set-on demand, ester-based wellbore fluids and methods of using the same


A turbocharger includes a drive shaft to transmit a driving force of an actuator to a mechanism in the turbo housing, and a bush to rotatably support the drive shaft, wherein a seal is provided at an end portion on the open-air side of the bush. The seal includes a seal body made of resin and a metallic spring fitted into a recessed portion of the seal body, wherein an internal lip portion of the seal body is pressed by the elastic force of the spring to the outer circumferential surface of the drive shaft. Further, an end surface that is contactable with a member (drive link) disposed on the open-air side of the drive shaft is formed in the seal body. The seal having the above-described structure is provided at the end portion on the open-air side of the bush so as to achieve excellent sealability, so that this securely prevents exhaust gas in the turbo housing from passing through between the outer circumferential surface of the drive shaft and the inner circumferential surface of the bush and flowing out to the outside.

An internal combustion engine (hereinafter referred to as an engine) mounted in a vehicle and the like is equipped with a turbocharger (supercharger) that utilizes exhaust energy. Generally, the turbocharger includes a turbine wheel that is rotated by exhaust gas flowing through an exhaust path of the engine, a compressor impeller to forcibly transfer air in an intake path to a combustion chamber of the engine, and a link shaft to link the turbine wheel with the compressor impeller. With respect to the turbocharger with the structure described above, the turbine wheel disposed in the exhaust path is rotated by the exhaust energy, which allows the compressor impeller disposed in the intake path to rotate in accordance with the rotation of the turbine wheel so as to provide supercharged intake air and forcibly transfer the supercharged air to the combustion chamber of each cylinder of the engine.
As for the turbocharger of this type, there has been known a variable nozzle vane type turbocharger in which supercharged pressure with respect to the exhaust energy is adjustable.
For example, the variable nozzle vane type turbocharger includes a variable nozzle vane mechanism that includes a plurality of nozzle vanes (also referred to as variable vanes) that are disposed in the exhaust gas flow path of a turbine housing and configured to change the flow path area of the exhaust gas flow path, an actuator to provide displacement (rotation) for the nozzle vanes, and the like. The turbocharger changes the opening degree of the nozzle vanes so as to change the flow path area (throat area) between the nozzle vanes adjoined to each other, whereby adjusting the velocity of the exhaust gas introduced to the turbine wheel (for example, see Patent Documents 1 to 3). Thus, the adjustment of the velocity of the exhaust gas is carried out, so that the rotational velocity of the turbine wheel and the compressor impeller can be adjusted, and the pressure of air introduced to the combustion chamber of the engine can be adjusted, which, for example, makes it possible to improve torque responsiveness associated with acceleration and the degree of freedom of conformity in terms of output, fuel consumption (fuel consumption rate), and emission. Also, with respect to the turbocharger, as a method of controlling supercharged pressure, for example, there has been a method in which an exhaust bypass path to bypass the turbine wheel is provided, and a wastegate valve to open and close the exhaust bypass path is provided, and the opening degree of the wastegate valve is adjusted, and the amount of the exhaust gas that bypasses the turbine wheel is adjusted, so as to control the supercharged pressure (see Patent Document 2).


A coating application system may include a pair of towers movable along a respective pair of floor tracks. A crossbeam may extend between the pair of towers. The cross beam may have opposing beam ends. A universal joint may couple each beam end to a tower to allow the crossbeam to rotate about a vertical axis and about a horizontal axis. A robotic device may be mounted to the crossbeam. The robotic device may include an end effector for performing one or more operations on an aircraft exterior surface.

The painting of an aircraft is a relatively challenging and time-consuming process due to the wide range of dimensions and unique geometry associated with aircraft. For example, the wings extending outwardly from the fuselage present geometry that can interfere with the painting process. The height of the vertical tail above the horizontal tail can present challenges in accessing the exterior surfaces of the vertical tail. In this regard, the process of painting an aircraft may require access by personnel to the aircraft exterior surfaces for manual operations such as sanding, cleaning, and masking of the surfaces prior to the application of one or more coatings of primer and paint, followed by de-masking and inspection of the aircraft surfaces.
The application of coatings to aircraft exterior surfaces must also be performed in a precise manner. For example, the process of applying paint to the aircraft surfaces must be carried out with a high level of control to ensure an acceptable level of coating thickness to meet performance requirements and visual expectations. The process of painting is further challenged by the large amount of exterior surface area of an aircraft.
As can be seen, there exists a need in the art for a system and method for applying a coating to an aircraft that can be accurately performed in a relatively low-cost manner and in a reduced amount of time.

Aircraft coating application system and method


A method receives an intermediate graphical representation (IGR) of a document, the IGR including a plurality of non-intersecting edges and determines a plurality of vertices using the IGR. The vertices include endpoints of the edges and a split point, being determined by splitting a first edge into two or more portions using an endpoint of at least one second edge, wherein the first edge and the second edge are from the plurality of non-intersecting edges, associates vertices from the plurality of vertices with at least one edge from the IGR using endpoints of the one edge, wherein the associating includes selecting, from the determined plurality of vertices, a plurality of neighbouring vertices to said one edge to define a region with the endpoints of the one edge. The method processes the region using at least the endpoints of said one edge and the associated neighbouring vertices.

In some printing architectures, measures such as removing overlapping objects, combining complex objects, and flattening compositing stacks are highly desirable steps to take. In some cases, some components in a printing architecture may only partially support a drawing interface over which graphical objects are sent, and so such steps are necessary to successfully print any print job. In other cases, such steps are desirable to improve the performance of a subsequent rasterisation processing step.
An object-based graphics system known as a Raster Image Processor (RIP) can generate an intermediate graphic representation of a page from a PDL (page description language) document, such as a PDF or PostScript document. The intermediate graphic representation represents the same page as the original PDL document, but in a format more suitable for rendering by a printer engine onto a print media, such as paper. One such intermediate graphic representation format is an edge-based representation, where each region is encoded only by an activating edge and colour data associated with the activating edge. This format is efficient for rasterising the page into an image as all overlapping regions have been resolved. This format is therefore also highly suited to processing steps often performed by a rasterisation module, such as combining complex objects and flattening compositing stacks.
Thus, one way of performing processing steps such as resolving overlaps between objects, combining complex objects, and flattening compositing stacks is to use a RIP system to generate an edge-based representation. One drawback of this approach is that the edge-based representation does not explicitly store the full boundaries of each non-overlapping object. This can hinder subsequent processing steps which rely on knowing the boundaries of each region.
One method of determining the boundaries of each region in an edge-based representation is to rasterise the edge-based representation, and then apply a pixel-wise outline extractor algorithm in order to detect and extract each region. However, this approach is cumbersome and slow as it involves rasterising the entire edge-based representation format into an image first, and then detecting the boundary of the regions by inspecting the image on a pixel-by-pixel basis.
Another method converts a PDL page to an intermediate non-overlapping object representation. However, this method cannot easily be used with a RIP system which efficiently performs processing such as combining complex objects and flattening compositing stacks, because the output of the RIP system is an edge-based representation, not a PDL page representation.

Method of detecting regions in an edge-based representation


In one embodiment, a method of forming doped regions in a substrate of a back side contact solar cell includes the steps of depositing a first doped oxide layer on a back side of a substrate, depositing a first undoped oxide layer over the first doped oxide layer, diffusing a first dopant from the first doped oxide layer into the substrate to form a first doped region in the substrate, and diffusing a second dopant into the substrate by way of a front side of the substrate, wherein the diffusion of the first dopant and the second dopant into the substrate are performed in-situ. The method may further include the steps of patterning the first doped and undoped oxide layers to expose portions of the back side of the substrate and depositing a second doped and undoped oxide layers on the back side of the substrate.

1. Field of the Invention
The present invention relates generally to solar cells, and more particularly but not exclusively to methods and apparatus for fabricating solar cells.
2. Description of the Background Art
Solar cells are well known devices for converting solar radiation to electrical energy. They may be fabricated on a semiconductor wafer using semiconductor processing technology. Generally speaking, a solar cell may be fabricated by forming p-doped and n-doped regions in a silicon substrate. Solar radiation impinging on the solar cell creates electrons and holes that migrate to the p-doped and n-doped regions, thereby creating voltage differentials between the doped regions. In a back side contact solar cell, the doped regions are coupled to metal contacts on the back side of the solar cell to allow an external electrical circuit to be coupled to and be powered by the solar cell. Back side contact solar cells are also disclosed in U.S. Pat. Nos. 5,053,083 and 4,927,770, which are both incorporated herein by reference in their entirety.
Just like in most manufacturing processes, each step employed in the manufacture of solar cells has an associated cost. Thus, techniques for simplifying the fabrication of solar cells are generally desirable.

This patent is subject to a terminal disclaimer.

Use of doped silicon dioxide in the fabrication of solar cells