Hydrogels of polymerized and crosslinked macromers comprising hydrophilic oligomers having biodegradable monomeric or oligomeric extensions, which biodegradable extensions are terminated on free ends with end cap monomers or oligomers capable of polymerization and cross linking are described. The hydrophilic core itself may be degradable, thus combining the core and extension functions. Macromers are polymerized using free radical initiators under the influence of long wavelength ultraviolet light, visible light excitation or thermal energy. Biodegradation occurs at the linkages within the extension oligomers and results in fragments which are non-toxic and easily removed from the body. Preferred applications for the hydrogels include prevention of adhesion formation after surgical procedures, controlled release of drugs and other bioactive species, temporary protection or separation of tissue surfaces, adhering of sealing tissues together, and preventing the attachment of cells to tissue surfaces.

This is a continuation-in-part of U.S. patent application Ser. No. 07/843,485, filed Feb. 28, 1992, entitled "Photopolymerizable Biodegradable Hydrogels as Tissue Contacting Materials and Controlled Release Carriers" by Jeffrey A. Hubbell, Chandrashekhar P. Pathak, and Amarpreet S. Sawhney.
Hydrogels as Controlled-Release Carriers
Biodegradable hydrogels can be carriers for biologically active materials such as hormones, enzymes, antibiotics, antineoplastic agents, and cell suspensions. Temporary preservation of functional properties of a carried species, as well as controlled release of the species into local tissues or systemic circulation, are possible. Proper choice of hydrogel macromers can produce membranes with a range of permeability, pore sizes and degradation rates suitable for a variety of applications in surgery, medical diagnosis and treatment.
Adhesives and Sealers
Fibrin gels have been used extensively in Europe as sealants and adhesives in surgery (Thompson et al., 1988, "Fibrin Glue: A review of its preparation, efficacy, and adverse effects as a topical hemostat," Drug Intell. and Clin. Pharm., 22:946; Gibble et al., 1990, (1990), "Fibrin glue: the perfect operative sealant?" Transfusion, 30(8):741). However, they have not been used extensively in the United States due to concerns relating to disease transmission from blood products. Synthetic polymers have been explored as adhesives (Lipatova, 1986, "Medical polymer adhesives," Advances in Polymer Science 79:65-93), but these materials have been associated with local inflammation, cytotoxicity, and poor biocompatibility.
Prevention of Postoperative Adhesions.
Formation of post-surgical adhesions involving organs of the peritoneal cavity and the peritoneal wall is a frequent and undesirable result of abdominal surgery. Surgical trauma to the tissue caused by handling and drying results in release of a serosanguinous (proteinaceous) exudate which tends to collect in the pelvic cavity (Holtz, G., 1984). If the exudate is not absorbed or lysed within this period it becomes ingrown with fibroblasts, and subsequent collagen deposition leads to adhesion formation.
Numerous approaches to elimination of adhesion formation have been Attempted, with limited success in most cases. Approaches have included lavage of the peritoneal cavity, administration of pharmacological agents, and the application of barriers to mechanically separate tissues. For example, Boyers et al., (1988) "Reduction of postoperative pelvic adhesions in the rabbit with Gore-Tex surgical membrane," Fertil. Steril., 49:1066, examined Gore-Tex surgical membranes in the prevention of adhesions. For a review of adhesion prevention, see Holtz (1984) "Prevention and management of peritoneal adhesions," Fertil. Steril., 41:497-507. However, none of these approaches has been cost effective and effective in in vivo studies.
Solutions of Poloxamer 407 have been used for the treatment of adhesions, with some success. Poloxamer is a copolymer of ethylene oxide and propylene oxide and is soluble in water; the solutions are liquids at room temperature. Steinleitner et al. (1991) "Poloxamer 407 as an Intraperitoneal Barrier Material for the Prevention of Postsurgical Adhesion Formation and Reformation in Rodent Models for Reproductive Surgery," Obstetrics and Gynecology, 77(1):48 and Leach et al. (1990) "Reduction of postoperative adhesions in the rat uterine horn model with poloxamer 407, Am. J. Obstet. Gynecol., 162(5):1317, examined Poloxamer solutions in peritoneal adhesion models and observed statistically significant reductions in adhesions; however, they were unable to eliminate adhesions, perhaps because of limited adhesion and retention on the injury site.
Oxidized regenerated cellulose has been used extensively to prevent adhesions and is an approved clinical product, trade-named Interceed TC7. This barrier material has been shown to be somewhat effective in rabbits (Linsky et al., 1987 "Adhesion reduction in a rabbit uterine horn model using TC-7," J. Reprod. Med., 32:17; Diamond et al., 1987 "Pathogenesis of adhesions formation/reformation: applications to reproductive surgery," Microsurgery, 8:103) and in humans (Interceed (TC7) Adhesion Barrier Study Group, 1989). It was shown to be more effective if pretreated with heparin, but was still unable to completely eliminate adhesions (Diamond et al., 1991 "Synergistic effects of INTERCEED(TC7) and heparin in reducing adhesion formation in the rabbit uterine horn model," Fertility and Sterility, 55(2):389).
In summary, several lavage/drug/material approaches have been explored, but none of these approaches has been able to eliminate adhesions. An ideal material barrier would not evoke an adhesion response itself, stay in place without suturing (Holtz et al., 1982 "Adhesion induction by suture of varying tissue reactivity and caliber," Int. J. Fert., 27:134), degrade over a few weeks' time, effectively reduce adhesions to very low extent, and be capable of delivering a drug to the local site of application for several days' time. None of the approaches developed and described to date meet these requirements.
Synthetic Biodegradable Polymers
The field of biodegradable polymers has developed rapidly since the synthesis and biodegradability of polylactic acid was first reported by Kulkarni et al., 1966 "Polylactic acid for surgical implants," Arch. Surg., 93:839. Several other polymers are known to biodegrade, including polyanhydrides and polyorthoesters, which take advantage of labile backbone linkages, as reported by Domb et al., 1989 Macromolecules, 22:3200; Heller et al., 1990 Biodegradable Polymers as Drug Delivery Systems, Chasin, M. and Langer, R., Eds., Dekker, New York, 121-161. Since it is desirable to have polymers that degrade into naturally occurring materials, polyaminoacids have been synthesized, as reported by Miyake et al., 1974, for in vivo use. This was the basis for using polyesters (Holland et al., 1986 Controlled Release, 4:155-180) of .alpha.-hydroxy acids (viz., lactic acid, glycolic acid), which remain the most widely used biodegradable materials for applications ranging from closure devices (sutures and staples) to drug delivery systems (U.S. Pat. No. 4,741,337 to Smith et al.; Spilizewski et al., 1985 "The effect of hydrocortisone loaded poly(dl-lactide) films on the inflammatory response," J. Control. Rel. 2:197-203).
The time required for a polymer to degrade can be tailored by selecting appropriate monomers. Differences in crystallinity also alter degradation rates. Due to the relatively hydrophobic nature of these polymers, actual mass loss only begins when the oligomeric fragments are small enough to be water soluble. Hence, initial polymer molecular weight influences the degradation rate.
Degradable polymers containing water-soluble polymer elements have been described. Sawhney et al., (1990) "Rapidly degraded terpolymers of dl-lactide, glycolide, and .epsilon.-caprolactone with increased hydrophilicity by copolymerization with polyethers," J. Biomed. Mater. Res. 24:1397-1411, copolymerized lactide, glycolide and .epsilon.-caprolactone with PEG to increase its hydrophilicity and degradation rate. U.S. Pat. No. 4,716,203 to Casey et al (1987) synthesized a PGA-PEG-PGA block copolymer, with PEG content ranging from 5-25% by mass. U.S. Pat. No. 4,716,203 to Casey et al. (1987) also reports synthesis of PGA-PEG diblock copolymers, again with PEG ranging from 5-25%. U.S. Pat. No. 4,526,938 to Churchill et al. (1985) described noncrosslinked materials with MW in excess of 5,000, based on similar compositions with PEG; although these materials are not water soluble. Cohn et al. (1988) J. Biomed. Mater. Res. 22:993-1009 described PLA-PEG copolymers that swell in water up to 60%; these polymers also are not soluble in water, and are not crosslinked. The features that are common to these materials is that they use both water-soluble polymers and degradable polymers, and that they are insoluble in water, collectively swelling up to about 60%.
Degradable materials of biological origin are well known, for example, crosslinked gelatin. Hyaluronic acid has been crosslinked and used as a degradable swelling polymer for biomedical applications (U.S. Pat. No. 4,987,744 to della Valle et al., U.S. Pat. No. 4,957,744 to Della Valle et al. (1991) "Surface modification of polymeric biomaterials for reduced thrombogenicity," Polym. Mater. Sci. Eng., 62:731-735).
Use of Biodegradable Materials for Controlled Drug Release.
Most hydrophilic drugs are mechanically dispersed as suspensions within solutions of biodegradable polymers in organic solvents. Protein and enzyme molecular conformations are frequently different under these circumstances than they would be in aqueous media. An enzyme dispersed in such a hydrophobic matrix is usually present in an inactive conformation until it is released into the surrounding aqueous environment subsequent to polymer degradation. Additionally, some proteins may be irreversibly denatured by contact with organic solvents used in dispersing the protein within the polymer.
Polymer Synthesis, Degradation and Local Synthesis
Rapidly-degrading polymers currently suggested for short-term macromolecular drug release may raise local concentrations of potentially hazardous acidic degradation byproducts. Further, all biodegradable synthetic polymers reported thus far can only be processed in organic solvents and all biodegradable polymers are synthesized under conditions which are not amenable to polymerization in vivo. Thus, it has not been possible to make implantable materials as precisely conformed barriers, shaped articles, or membranes capable of delivering bioactive materials to the local tissue.
It is therefore an object of the present invention to provide hydrogels which are biocompatible, biodegradable, and can be rapidly formed by polymerization in vivo.
It is a further object of the present invention to provide a macromer solution which can be administered during surgery or outpatient procedures and polymerized as a tissue adhesive, tissue encapsulating medium, tissue support, or drug delivery medium.
It is a still further object of the present invention to provide a macromer solution which can be polymerized in vivo in a very short time frame and in very thin, or ultrathin, layers.

Photopolymerizable biodegradable hydrogels as tissue contacting materials and controlled-release carriers

Board of Regents, The University of Texas System


A liquid ejection apparatus including a liquid supply unit having a supply unit case for accommodating a liquid charging portion, and a main body having a supply unit arranging part for arranging the liquid supply unit and a carriage part for moving along the vicinity of the supply unit arranging part, wherein the carriage side of the liquid supply unit arranged in the supply unit arranging part is provided with an information storing unit mounting portion formed to be protruded toward the carriage side, the supply unit arranging part is provided with a through window portion for causing the information storing unit mounting portion to penetrate therethrough, and carriage side information storing unit is formed in a portion corresponding to the through window portion in the carriage part for moving in the vicinity of the through window portion.

1. Field of the Invention
The present invention relates to a liquid ejection apparatus such as an image recording apparatus, for example, a printer.
2. Related Art
In general, a printer to be an ink jet type recording apparatus has an ink cartridge mounted on a carriage including an ink jet type recording head and employs a method in which the ink jet type recording head carries out printing upon receipt of the supply of an ink from the ink cartridge.
However, the printer of this kind has the capacity of the ink cartridge to be mounted on the carriage which is small, and cannot correspond to a comparatively large amount of printing for an office or business, for example. For this reason, there has been employed a method in which the ink cartridge is not provided on the carriage but on the ink jet recording apparatus body side, and a subtank is mounted on the carriage to supply an ink from the ink cartridge to the subtank (for example, see Japanese Patent Publication No. JP-A-2002-1980, FIG. 1).
Moreover, the ink jet type recording head provided in the printer has such a structure as to receive data on the type and residual amount of an ink charged in the ink cartridge, a serial number and an expiration date from the ink cartridge, thereby ejecting the ink properly.
For this reason, the ink cartridge is provided with an IC chip storing the data and a communicating portion for transferring the data in contact with the IC chip is provided in the printer. The communicating portion has such a structure as to be connected to the ink cartridge.
More specifically, the IC chip of the ink cartridge has such a structure as to supply data on the type of the ink to the printer through the connecting terminal of the communicating portion.
When the connecting terminal of the communicating portion is to transfer data together with the IC chip of the ink cartridge, they are to come in contact with each other.
For this reason, the data cannot be transferred until the position of the IC chip of the ink cartridge and that of the connecting terminal of the communicating portion are accurately set. Therefore, there is a problem in that the positioning is to be carried out accurately.
Moreover, data are varied every ink cartridge. Therefore, it is necessary to provide, in the communicating portion, the same number of connecting terminals as the number of the ink cartridges. Consequently, there is also a problem in that a cost cannot be reduced.
On the other hand, there is also a problem in that precision in the transfer of information is reduced when the information is transferred in non-contact without using the connecting terminal.


One embodiment of the present invention provides a system that augments a circuit design with a mechanism for detecting and correcting timing errors. This system first partitions the circuit into a set of blocks that are clocked by an independent clock source, and integrates an error signal propagation circuit between the set of blocks. For a respective block, the system determines a set of internal registers that are to be implemented as double data sampling registers, and replaces the determined set of internal registers with double data sampling registers, wherein a given double data sampling register is configured to generate an error signal when it detects a timing error. Then, the system integrates a two-phase error correction circuit into the respective block, wherein when notified of a timing error by a double data sampling register, the two-phase error correction circuit is configured to stall registers in the respective block.

1. Field of the Invention
The present invention generally relates to techniques and systems for detecting and correcting errors in a circuit. More specifically, the present invention relates to techniques and systems for augmenting a circuit design to detect and correct timing errors.
2. Related Art
Advances in semiconductor fabrication technology have given rise to dramatic increases in the number of transistors per semiconductor device by fabricating smaller transistors and compacting these transistors closer together. However, these new design practices can make a fabricated integrated circuit (IC) more vulnerable to physical faults or parasitic effects that can influence the performance of the IC. In response to these potential dangers, ICs are often designed with redundancy, error detection, and error correction whenever possible to make these circuits more robust. However, the performance and layout overhead associated with such error detection and correction circuits can make them prohibitive in a new circuit design.
Timing delay errors for a manufactured IC, in particular, are difficult to estimate and prevent during the initial design cycle for an IC. These errors occur when the computation for a given input vector cannot be completed before registers are sampled to capture a produced result. In some occasions, a timing delay error can occur in a manufactured IC as a result of a random manufacturing error, at which point the faulty IC can be discarded. However, when a timing delay error is encountered across a batch of manufactured ICs, the clock frequency for the ICs can be lowered to allow the ICs to operate correctly, but at the cost of sacrificing the performance level that the ICs were designed to operate under.
On the other hand, a manufactured IC may be capable of functioning at a higher frequency than was predicted for its circuit design. When a given circuit is designed and implemented, the circuit is generally designed to operate within a conservative set of values for process and environmental variables (i.e., a design corner). Moreover, the timing predictions for the circuit generated by analysis algorithms and models are usually padded to account for their inability to model some physical, electrical, and/or logic effects. These predictions produce a design margin, which is the difference in timing between the manufactured circuit and the analysis result, and it is a measure of how conservative the performance predictions are for a design process. When the assumed worst case scenarios fail to materialize in silicon due to a large design margin, the outcome of the large design margin is an overdesigned circuit, which is undesirable. It is common practice for a fabricated IC to be tested under a wide range of power and clock frequency parameters to determine the actual functioning parameters of the IC. A breaking point of the IC is usually found once the IC experiences timing errors.
A number of solutions have been developed for detecting and correcting timing errors, and a number of these solutions are based on double data sampling registers (DDSRs). A DDSR is a modified flip flop (FF) that is capable of detecting delay errors by using an extra "shadow" latch that samples the data later than a standard register, and then comparing the two sampled data for differences. If the "shadow" latch of the DDSR samples a value that is different than the regular latch of the DDSR, then the DDSR determines that it has detected an error. Once an error has been detected by a DDSR, an error signal is propagated to logic in the design that can correct the error.
However, existing systems that utilize DDSRs to implement an error detection circuit often require the presence of a specialized pipeline organization of the circuit, and perform error correction by flushing the pipeline and replaying the instructions/data. Two common DDSR solutions for performing error detection and error correction include:                Correcting an error in situ by either stalling the clock to allow time for replacing the incorrect value with the correct value from the "shadow" latch, or by stalling the data in a modified pipeline design.        Flushing a circuit pipeline after detecting an error in the pipeline, and allowing the circuit pipeline to recompute the results.
These implementations can impose a large physical overhead on a given circuit design, and can introduce a significant performance loss when flushing the pipeline to perform error correction. The first solution can impose strict limitations on what class of circuits can be augmented with the error detection and correction capabilities, as it requires simple pipelines. Furthermore, it also imposes a large circuit overhead due to its error correction mechanism and the modified circuit pipelines. The first solution is typically used for custom circuit designs, where error detection and error correction is applied to specific portions of the design. The second solution is not widely used to augment general ASIC designs with error detection and correction capabilities because it can impose a large performance overhead whenever an error is detected.

Two-phase clock-stalling technique for error detection and error correction


A level shifter circuit for ensuring a high impedance state even in a transitional period such as when activating an external power supply while reducing power consumption. A latch circuit is set to a low level by a set circuit when a high potential power supply voltage increases. When the high potential power supply voltage exceeds a threshold voltage, a p-channel MOS transistor of the latch circuit is activated and the high potential power supply voltage is applied to a first transistor via a connection node. When a high potential enable signal having normal high level signal voltage is provided to a second transistor, which is connected to the first transistor, the reset circuit provides the high level signal to the latch circuit and stops the voltage application to the first transistor via the connection node.

The present invention relates to a level shifter circuit for converting a voltage of a high level input signal into a high voltage in accordance with the input signal and outputting the high voltage and for further outputting a high impedance state using an output enable signal.
A level shifter circuit is known as a circuit for converting a low voltage signal to a high voltage signal. The level shifter circuit includes a circuit that performs a three-state output. The three states include low level output performed in accordance with the input level, high level output performed in accordance with the input level, and high impedance state output. The level shifter circuit for outputting three states includes a circuit that uses an output enable signal to determine whether to perform an output corresponding to the input level or a high impedance state output (refer to, for example, FIG. 1 of Japanese Laid-Open Patent Publication No. 2005-33530, and FIG. 2 of Japanese Laid-Open Patent Publication No. 8-307242).
Japanese Laid-Open Patent Publication No. 2005-33530 and Japanese Laid-Open Patent Publication No. 8-307242 each describe a level shifter circuit including an n-channel MOS transistor, which controls connection between an output terminal and a ground voltage line, and a p-channel MOS transistor, which controls connection between the output terminal and a high potential power supply voltage line. The level shifter circuit activates and deactivates the n-channel MOS transistor and the p-channel transistor in accordance with an output enable signal and an input signal to determine the output. The p-channel MOS transistor is activated when its gate terminal is provided with a signal having a low level.
In the level shifter circuit of Japanese Laid-Open Patent Publication No. 2005-33530, the high potential power supply voltage line is connected to the gate terminal of the p-channel MOS transistor via a resistor. Thus, current is consumed by the resistor when maintaining the output of the high potential power supply voltage. This increases the power consumption. In this level shifter circuit, the n-channel MOS transistor is arranged between the n-channel MOS and the output terminal, and the p-channel MOS transistor is arranged between the p-channel. MOS transistor and the output terminal. This decreases the difference of the voltage applied to the transistors and suppresses the voltage to below the gate withstand voltage and the drain-source withstand voltage of each transistor. Thus, reliable operation of the level shifter circuit is ensured even when using a transistor of which the gate withstand voltage or the drain-source withstand voltage is not large.
In the level shifter circuit disclosed in Japanese Laid-Open Patent Publication No. 8-307242, the gate terminal of the p-channel MOS transistor is biased by two inverters, which are connected in series. The inverters use the high potential power supply voltage line as a power supply. Thus, the voltage at the gate terminal and the voltage at the source terminal of the p-channel can be substantially equalized. This reduces the power consumption.
However, the p-channel MOS transistor is not always deactivated during a transitional period such as when an external power supply is activated. In other words, in such level shifter circuits, a high impedance state cannot be maintained when the voltage rises.
The level shifter circuit 100 shown in FIG. 4 may also be used. The level shifter circuit 100 includes an input signal level shifter circuit 30 and an enable signal level shifter circuit 50. In this level shifter circuit 100, the output enable signal is set to a high level signal when outputting an output signal with a voltage corresponding to the input signal, and the output enable signal is set to a low level signal when the output is in the high impedance state.
The input signal level shifter circuit 30 outputs an output signal corresponding to the input signal when the output enable signal has a low level. Specifically, when the input signal has a low level, the input signal level shifter circuit 30 outputs the ground voltage GND, which has the same voltage as the input signal as an output voltage VOUT, or as a signal having the same low level as the input signal. Furthermore, when the input signal has a high level, a high potential power supply voltage HVDD, which has a higher voltage than the input signal, is output as the output voltage VOUT of a high level signal corresponding to the input signal.
Furthermore, when the output enable signal E1 has a high level, the enable signal level shifter circuit 50 outputs a signal (hereinafter referred to as high potential enable signal E2) having a level corresponding to the output enable signal, that is, a voltage higher than the voltage of the output enable signal E1. The enable signal level shifter circuit 50 also outputs an inverted signal of the output enable signal (output disable signal D1) and a signal (hereinafter high potential disable signal D2) having a level corresponding to the output disable signal. The high potential disable signal D2 has a voltage that is higher than the voltage of the output disable signal D1.
The input signal level shifter circuit 30 will now be described in detail.
As shown in FIG. 4, the input terminal of the level shifter circuit 100, to which input voltage VIN is applied, is connected to the gate terminal of a transistor N31, the input terminal of an inverter 33, and the gate terminal of a transistor N36 in the input signal level shifter circuit 30.
The transistor N31 is an n-channel MOS transistor, the source terminal of which is connected to the ground voltage GND line. The drain terminal of the transistor N31 is connected to the high potential power supply voltage HVDD line via a transistor N34, a transistor P34, and a transistor P31.
A low potential power supply voltage VDD is supplied to the inverter 33 serving as driving voltage. The output terminal of the inverter 33 is connected to the gate terminal of the transistor N32. The inverter 33 outputs the inverted signal of the input signal (high level signal of the low potential power supply voltage VDD or low level signal of the ground voltage GND).
The transistor N32 is an n-channel MOS transistor, the source terminal of which is connected to the ground voltage GND line. The drain terminal of the transistor N32 is connected to the high potential power supply voltage HVDD line via a transistor N35, a transistor P35, and a transistor P32.
The transistors N34 and N35 are n-channel MOS transistors, the gate terminals to which a voltage Vn having a fixed value is applied in a normal state. The voltage Vn is a voltage that activates the n-channel MOS transistor having the source terminal to which the ground voltage GND is applied. Further, the voltage Vn is higher than the ground voltage GND by about 3 V. The transistors P34 and P35 are p-channel MOS transistors, the gate terminals to which a voltage Vp having a fixed value is applied in a normal state. The voltage Vp is a voltage that activates the p-channel MOS transistor having the source terminal to which the high potential power supply voltage HVDD is applied. The voltage Vp is a voltage lower than the high potential power supply voltage HVDD by about 3 V. In the preferred embodiment, the voltage Vp is higher than the voltage Vn. When the high potential power supply voltage HVDD is small, the relation of the voltages Vp and Vn with respect to magnitude is reversed.
The transistors P31 and P32 are p-channel MOS transistors. The source terminals of the transistors P31 and P32 are connected to the high potential power supply voltage HVDD line. The source of the transistor P34 and the gate terminal of the transistor P32 are connected to the drain terminal of the transistor P31. The source terminal of the transistor P35 and the gate terminal of the transistor P31 are connected to the drain terminal of the transistor P32. The gate terminal of a transistor P36 is also connected to the drain terminal of the transistor P32.
The transistor P36 is a p-channel MOS transistor, the source terminal of which is connected to the high potential power supply voltage HVDD line. The drain terminal of the transistor P36 is connected to the drain terminal of a transistor P40 serving as a first switch element and the gate terminal of a transistor P41 serving as a first output control element.
The transistors P40 and P41 are p-channel MOS transistors, the source terminals of which are connected to the high potential power supply voltage HVDD line. The high potential enable signal E2 is provided to the gate terminal of the transistor P40. The voltage of the high potential enable signal E2 becomes the high potential power supply voltage HVDD when the output enable signal E1 has a high level. When the output disable signal D1 has a high level and a transistor P52 is deactivated, the high potential enable signal E2 decreases until a transistor P55 is deactivated, and becomes the voltage determined by the voltage Vp and the threshold voltage Vthp of a transistor P38 (about "voltage Vp+threshold voltage Vthp"). The transistor P41 is connected via the transistor P42 to the output terminal that outputs the output voltage VOUT. The transistor P42 is a p-channel MOS transistor having a gate terminal to which the voltage Vp is applied.
The drain terminal of the transistor P36 is connected to the ground voltage GND line via the transistor P38, a transistor N38, a transistor N37, and the transistor N36. The transistor P38 p-channel MOS transistor having a gate terminal to which voltage Vp is applied. The transistor N38 is an n-channel MOS transistor having a gate terminal to which voltage Vn is applied. The transistor N37 is an n-channel MOS transistor, the gate terminal of which is provided with the output enable signal E1.
The transistor N36 is an n-channel MOS transistor having a gate terminal to which the input voltage VIN is applied, a source terminal connected to the ground voltage GND line, and a drain terminal connected to the source terminal of the transistor N37. The drain terminal of the transistor N36 is also connected to the drain terminal of a transistor N40 serving as a second switch element and the gate terminal of a transistor N41 serving as a second output control element. The transistors N40 and N41 are n-channel MOS transistors, the source terminals of which are connected to the ground voltage GND line.
The output disable signal D1 is provided to the gate terminal of the transistors N40. The transistor N41 is connected via a transistor N42 to the output terminal that outputs the output voltage VOUT. The transistor N42 is an n-channel MOS transistor having a gate terminal to which the voltage Vn is applied.
The enable signal level shifter circuit 50 will now be described in detail.
As shown in FIG. 4, the output enable signal E1 is provided to the gate terminal of a transistor N51 and to the input terminal of an inverter 53 in the enable signal level shifter circuit 50.
The transistor N51 is an n-channel MOS transistor having a source terminal connected to the ground voltage GND line and a drain terminal connected to the high potential power supply voltage HVDD line via a transistor N54, a transistor P54, and a transistor P51.
The inverter 53 is supplied with low voltage power supply voltage VDD serving as driving voltage. The output terminal of the inverter 53 is connected to the gate terminal of a transistor N52. The output terminal of the inverter 53 outputs the inverted signal of the output enable signal E1. The output signal from the inverter 53 becomes the output disable signal D1.
The transistor N52 of which gate terminal is connected to the output terminal of the inverter 53 is an n-channel MOS transistor. The transistor N52 has a source terminal connected to the ground voltage GND line and a drain terminal connected to the high potential power supply voltage HVDD line via a transistor N55, a transistor P55, and a transistor P52.
The transistors N54 and N55 are n-channel MOS transistors having gate terminals to which the voltage Vn is applied. The transistors P54 and P55 are p-channel MOS transistors having gate terminals to which the voltage Vp is applied.
The transistors P51 and P52 are p-channel MOS transistors. The source terminals of the transistors P51, P52 are connected to the high potential power supply voltage HVDD line. The source terminal of the transistor P54 and the gate terminal of the transistor P52 are connected to the drain terminal of the transistor P51. A signal from the drain terminal of the transistor P51 becomes the high potential disable signal D2. The source terminal of the transistor P55 and the gate terminal of the transistor P51 are connected to the drain terminal of the transistor P52. A signal from the drain terminal of the transistor P52 becomes the high potential enable signal E2.
When setting the level shifter circuit 100 to the high impedance state, the output enable signal E1 is set to a low level. This shifts the output disable signal D1 to a high level, activates the transistor N40, and the voltage at the drain terminal of the transistor N40 becomes the ground voltage GND. As a result, the voltage of the gate terminal of the transistor N41 also becomes the ground voltage GND. This deactivates the transistor N41.
When the output enable signal E1 is set to the low level, the high potential enable signal E2 also shifts to a low level. Therefore, voltage having a low level is applied to the gate terminal of the transistor P40. This activates the transistor P40 and the voltage at the drain terminal of the transistor P40 becomes the high potential power supply voltage HVDD. This results in the voltage at the gate terminal of the transistor P41 becoming the high potential power supply voltage HVDD. Thus, the transistor P41 is deactivated.
The transistor N37 of which gate terminal receives the output enable signal E1 is deactivated. As a result, current does not flow through the transistor P40 and the transistor N40. Thus, the voltage at the drain terminal of the transistor P40 approaches the high potential power supply voltage HVDD, and the voltage at the drain terminal of the transistor N40 approaches the ground voltage GND. This ensures that the high impedance is maintained.
In this manner, when the output enable signal is set to low level, the transistors N41 and P41 on both sides of the output terminal are deactivated. Thus, the level shifter circuit 100 enters the high impedance state.
In the level shifter circuit 100 shown in FIG. 4, the transistor P41 must be deactivated to obtain the high impedance state, as described above. Thus, in the level shifter circuit 100, the transistor P40 is activated to apply the high potential power supply voltage HVDD to the gate terminal of the transistor P41. Then, the high potential power supply voltage HVDD is applied to the gate terminal of the transistor P41, and the transistor P41 is deactivated. Furthermore, the high potential enable signal E2 is provided to the gate terminal of the transistor P40 to activate the transistor P40.
During activation of the power supply, the voltage value of the high potential enable signal E2 and the voltage value of the high potential disable signal D2 in the level shifter circuit 100 may be unstable when the voltages Vn and Vp have not yet been supplied even though circuits operated by low voltages such as the low potential power supply voltage VDD have already been activated. In this case, when the voltages of the high potential enable signal E2 and the high potential disable signal D2 are close to the high potential power supply voltage HVDD, activation of the transistor P40 cannot be ensured. As a result, the transistor P41 may not be deactivated. Accordingly, the high potential power supply voltage HVDD may not be applied to the gate terminal of the transistor P41 depending on the input signal. Thus, the level shifter circuit 100 may not enter the high impedance state even though the output enable signal E1 has a low level.


A receiving station (7) is proposed, having a receiving unit which is designed for radio reception of data from a measurement sensor (1), with two or more channels at different frequencies being available for selection for data transmission, which can receive data continuously from the measurement sensor on a current channel when in standby. According to the invention, a control unit (1) is provided, which scans the frequencies of the channels and blocks those channels for further selection in which a predefined interference level is exceeded. A measurement sensor as well as a measurement system having a receiving station and having a measurement sensor are also proposed.

(1) Field of the Invention
The invention relates to a receiving station and to a measurement sensor having a receiving unit for the radio reception of data from a measurement sensor with two or more available channels at different frequencies for data transmission which can continuously receive data from a measurement sensor on a current channel when it is on standby. The invention also pertains to a measurement sensor having a transmitting device for the radio transmission of data to a receiving station in which two or more channels are available at different frequencies for the selection of data transmission in which the measurement sensor has a receiving device for the radio reception of data and can change from a current channel to a different channel which is determined by receiving predetermined control data and to a measurement system having a receiving station and a measurement sensor. More particularly the invention pertains to a control unit which scans the frequencies of the channels and blocks those channels for further selection when a predetermined interference level is exceeded.
(2) Description Of Related Art Including Information Disclosed Under 37 C.F.R. 1.97 and 1.98
Measurement probes are regularly used for measurement of workpieces on machine tools. In the case of one known embodiment, measurement data which is recorded by the measurement probe is transmitted by radio to a receiving station for further processing. Normal channels which can be selected manually are normally available for radio transmission.
Thus, in the situation where one channel is subject to interference, it is possible to select a different channel, in which there is less interference or no interference. The manual selection has to be made at the receiving station and in a corresponding manner, on the measurement probe.
It may be necessary to manually change the channel a number of times in order to find a good channel.

Receiving station, measurement sensor as well as a measurement system having a receiving station and having a measurement sensor


A molecular sieve blend with improved performance characteristics produced by preparing or obtaining a hydrophilic zeolite, particularly a hydrophilic zeolite A with a low SiO2:Al2O3 ratio, preparing or obtaining a hydrophobic silicon based binder, particularly a hydrophobic colloidal silica or a hydrophobic siloxane based material, mixing the zeolite with the silicon based binder and, in one embodiment, a seed containing small quantities of a clay binding agent and the zeolite, to form a mixture, and forming the mixture into the molecular sieve blend.

Various embodiments relate to molecular sieve blends containing a combination of a hydrophilic zeolite, and a hydrophobic silicon based binder and preferably, a seed, preferably formed in a granulation process, utilized in the preparation of the molecular sieve blends, wherein the seed, in one embodiment, contains a clay binding agent, and processes of manufacture and use of these molecular sieve blends, such as for dehydration of liquid and gaseous hydrocarbon streams, drying of cracked C1-C4 hydrocarbon gas streams, dehydration of ethanol feed streams, and removal of various undesired materials from various types of feed streams. (For purpose of this disclosure "molecular sieve blends" are alternatively referred to as "adsorbents", "adsorbent blends", "molecular sieve adsorbent blends" or "molecular sieve adsorbents" or similar terms.)
Zeolites are hydrated metal alumino silicates having the general formulaM2/nO:Al2O3:xSiO2:yH2Owhere M usually represents a metal of an alkali or alkaline earth group, n is the valence of the metal M, x varies from 2 to infinity, depending on the zeolite structural type and y designates the hydrated status of the zeolite. Most zeolites are three-dimensional crystals with a crystal size in the range of 0.1 to 30 μm. Heating these zeolites to high temperatures results in the loss of the water of hydration, leaving a crystalline structure with channels of molecular dimensions, offering a high surface area for the adsorption of inorganic or organic molecules. Adsorption of these molecules is dependent upon the size of the zeolite channels. The rate of adsorption is limited by the laws of diffusion.
Zeolites are used for a number of processes. The choice of zeolite is important in a number of chemical processes well known to those skilled in the art. For example, catalytic processes of interest using zeolites in the petrochemical industry include reforming, hydrocracking, dewaxing, isomerization, fluid catalitic cracking (FCC), partial oxidation, alkylation and disproportionation of aromatics. Zeolites are also used for dehydration, adsorption of various compounds from feed streams and separation of various hydrocarbons in a feed stream.
Molecular sieves have been advantageous for a number of processes as the diffusion of materials into and out of the pores can be facilitated based on the pore size that is present within the particular molecular sieve. (For purposes of this disclosure "zeolite" and "molecular sieve" have the same meaning.)
One limitation on the utilization of zeolites is their extremely fine particle size. Large, naturally-formed agglomerates of zeolite crystals break apart easily. In addition, because the pressure drop through a bed containing only such fine zeolite crystals is prohibitively high, these zeolite crystals cannot be used alone in fixed beds for various dynamic applications, such as drying of natural gas, drying of air, separation of impurities from a gas stream, separation of some gaseous and liquid product streams and the like. Therefore, it is necessary to agglomerate these zeolite crystals with binder materials to provide an agglomerate mass containing the zeolite crystals, which exhibits a reduced pressure drop.
To overcome these issues and permit the utilization of zeolite crystals, different types of clays have conventionally been used as binder materials for those crystals, wherein the clay binders have generally been selected from attapulgite, palygorskite, kaolin, sepiolite, bentonite, montmorillonite, other types of clays and mixtures thereof. Particularly useful clay binders are formed from attapulgites.
In one example of the utilization of a molecular sieve adsorbent, water is removed from a cracked gas stream, for example, for the production of ethylene. The molecular sieve adsorbent is utilized immediately before a cryogenic process to remove water so that ice is not created during the process. However, inherent in the process is the fact that the hydrocarbon feed stream contains unsaturated hydrocarbons, such as alkenes and dienes, which are very reactive. These unsaturated hydrocarbons tend to form oligomers and polymers, which act as bed fouling agents and are commonly referred to as green oil or coke. These agents block adsorption channels, reduce the working capacity of the bed for dehydration and reduce useful adsorption life of the adsorbent. Accordingly, it is also important that the molecular sieve adsorbents produce very low quantities of green oil or coke during an adsorption process. Many of the clay binders that have been traditionally used as binder materials with zeolites contain metallic acid sites that encourage polymer/oligomer formation by a catalytic reaction. Conventionally, these clay binder materials are treated with a de-activating agent such as a phosphate solution to reduce this catalytic activity. Notwithstanding, there are still issues associated with the production of green oil/coke during processes for treatment of hydrocarbon feed streams when clay materials are used as the binder material with zeolites.
Silicon based materials have sometimes been used as a binder material with high silica molecular sieves to form catalyst agglomerates for specialty catalytic reactions, wherein the molecular sieves used have included, for example, ZSM-5, Y zeolites and SAPO zeolites. Because of the hydrophobic nature of both the silicon based binders and the high silica zeolites, these catalytic materials have been limited in use to organic reactions. For example, hydrophobic silicon based binders blended with hydrophobic high silica zeolites have been utilized as catalytic materials in the petrochemical industry for reactions including reforming, hydrocracking, dewaxing, isomerization, partial oxidation, alkylation, disproportionation of aromatics, and particularly as fluid catalytic cracking catalysts. These catalytic reactions conventionally utilize hydrophobic zeolites having a high silica content, wherein the SiO2:Al2O3 ratio is at least 50, preferably greater than 200 and as high as 600 or so. To enhance the high silica content of these zeolites, they are often dealuminized to increase their silica:alumina ratio, making them even more hydrophobic. The silicon based binders used with these catalysts are also required to be highly hydrophobic. Binders used to produce catalysts for these catalytic reactions are not included within this disclosure. Further, the binders of this disclosure are not conventionally utilized to form these catalysts.
One problem with many conventionally formed zeolite agglomerate blends is decreased diffusion. The larger the diameter of the formed zeolites, the slower the rate of diffusion of the molecules to be adsorbed. Particularly in the field of pressure swing adsorption, this effect is highly adverse to short cycle time and thus to productivity. Enhanced kinetic values or faster mass transfer rates can result in shorter cycle time and lower power consumption and thus higher adsorbent productivity.
Another important issue in choosing an appropriate adsorbent is the ability of that adsorbent to selectively adsorb a compound that is desired to be removed from the processing stream without also adsorbing the desired component or components of that stream. For example, an important feature of adsorbents used to remove water from an ethanol feed stream is not only their water adsorption capacity but also that the quantity of ethanol that is adsorbed by the adsorbents is limited. Frequently, it is necessary to balance the relative adsorption capabilities of these adsorbents.
Accordingly, it is one intent to disclose a process for the production of molecular sieve blends which are effective and highly selective for the removal of water from hydrocarbon feed streams, such as those containing ethanol or cracked gases.
It is a still further intent to disclose molecular sieve blends which maintain their physical properties and diffusion capabilities even with a reduced quantity of binder than is conventionally used.
It is a still further intent to disclose molecular sieve blends which limit the production of undesired oligomers and polymers during utilization.
It is an additional intent to disclose a process for the preparation of molecular sieve blends with enhanced diffusion rates.
It is a still further intent to disclose a process for the production of molecular sieve blends containing a hydrophobic silicon based binder that are effective and selective for adsorption processes.
It is a still further intent to disclose molecular sieve blends comprising a low silica, hydrophilic zeolite blended with a hydrophobic silicon based binder.
It is a still further intent to disclose molecular sieve blends comprising a low silica, hydrophilic zeolite, a hydrophobic silicon based binder and a seed comprising, in one embodiment, a clay binding agent, wherein a granulation seed process is utilized to produce the seeds used for the production of the molecular sieve blends.
It is a still further intent to disclose molecular sieve blends comprising a low silica, hydrophilic zeolite blended with a hydrophobic silicon based binder, and a seed, preferably comprising a clay binding agent, wherein a granulation seed process is utilized for the production of the seed, and wherein the seeds utilized in the granulation seed process comprises less than 25% by volume of the molecular sieve blends.
It is still further intent to disclose molecular sieve blends comprising a low silica, hydrophilic zeolite blended with a hydrophobic silicon based binder and a seed, preferably comprising a clay binding agent, wherein a granulation seed process is utilized for the production of the seed, wherein the composition of the seeds comprises clay and the hydrophilic zeolite, and wherein the clay comprises less than 5% by weight of the overall molecular sieve blends.
It is a still further intent to disclose a process for drying a feed stream comprising passing the feed stream over molecular sieve adsorbent blends comprising a low silica, hydrophilic zeolite, a hydrophobic silicon based binder, and a seed used for the production of the molecular sieve blends, preferably comprising a clay binding agent and the hydrophilic zeolite.
It is a still further intent to disclose a process for the separation of polar materials using molecular sieve blends comprising a zeolite, particularly a low silica hydrophilic zeolite, more particularly a low silica hydrophilic zeolite 3A, a hydrophobic silicon based binder, particularly a hydrophobic colloidal silica binder or, in a less preferred embodiment, a hydrophobic siloxane based binder, and a seed used in the production of the molecular sieve blends, preferably comprising a clay binding agent and the hydrophilic zeolite.
It is still further intent to disclose a process for separation of components of a gaseous or liquid feed stream, particularly an ethanol feed stream, comprising passing that gaseous or liquid feed stream over molecular sieve blends comprising a low silica hydrophilic 3A zeolite powder, a hydrophobic colloidal silica binder or, in a less preferred embodiment, a hydrophobic siloxane based binder, and a seed used in the production of the molecular sieve blends, preferably comprising a clay binding agent and the hydrophilic zeolite.
These and other intents are obtained from the processes for production, the processes for use and the products of the various embodiments disclosed herein.

This patent is subject to a terminal disclaimer.

Molecular sieve adsorbent blends and uses thereof


A luff roller reefing and roller furling sail is provided with a luff pad (6) made up of a laminate of a sail fabric (1) adhesively bonded to a polyurethane elastomeric foam (3). The pad is then adhesively bonded and/or stitched to the length of the luff of a sail (5), tapered from mid-luff to the tack and head. A luff tape is preferably adhesively bonded and stitched over each face of the laminate. When the sail is furled, the tapered luff pad provides bulk to cause more fabric to be drawn from the central portion of the sail, reducing draft and controlling position of the draft in partially furled conditions, and maintaining aerodynamically sound shape in the sail for windward performance.

Roller furling and roller reefing (partial furling) of sails has come to be common and popular on a substantial variety of sailing vessels, and permits effective sail handling with reduced crew requirements and a host of other advantages.
In such systems, the sail is supported on and fixed to a stay which is adapted to rotate. When the sail is in place, it will be furled by being rolled around the outside of the rotatable stay. When fully rolled up, or furled, the sail may be left in place, ready for immediate use, not requiring stowage below decks, or crew handling to get it there. Unfurling is rapid and undemanding, so that making sail and getting under weigh is facilitated.
A wide variety of roller furling systems are known in the art, and do not per se form a part of the present invention, which is suitable for use with any such system.
Roller furling systems are also frequently employed in partially furled condition to reef the sail. In increased winds, where the sail area is greater than desirable, roller reefing is effective to reduce sail area, heeling moment, leeway, and to preserve control, particularly steering control, of the vessel. Roller reefing is progressive, and adaptable to wind and wave conditions as they occur. The alternative to reefing is to change to a smaller sail, which is demanding of crew and in some conditions working on the bow is hazardous. Other reefing techniques for headsails are not generally desirable, and represent little or no improvement on changing sails.
It is characteristic of such roller furling systems that as the luff of the sail is rolled on its stay, luff tension on the sail is decreased, and to a degree the bulk of material in the structure of the foot and leach of the sail cause the volume of material rolled around the stay to be greatest at the tack and the head. As a consequence, the sail develops excessive sag and draft in the center, and the location of the maximum draft moves aft. The problem is exacerbated by bias stretch of the sail fabric, which is ordinarily least controllable in the central portions of the sail structure. These aspects of roller furling are counter productive, as the shape of the sail is less effective, particularly for sailing to windward. Heeling moments remain higher than desirable, and boat performance is lost.
It has long been recognized that increasing the bulk of the roll in the mid-region of the luff of the sail as it is partially furled can alleviate much of the problem, and make roller reefing a far more effective technique. It is also known that the increased bulk of the furled sail on the stay is aerodynamically superior to the sag and stretch of the sail.
Such expedients as enlarging the central, mid-luff portion of the stay, or hoisting an elongated member along the luff to become rolled into the sail as the furling takes place have been tried. The enlarged stay is aerodynamically undesirable. The hoisting of a luff "partner" is a backward step, since it puts the crew back on the bow of the vessel in dangerous conditions and circumstances.

Luff pad for roller reefing and furling sails


A burner is provided with a burner block having a recess formed in the back thereof for receiving a fuel atomiser and a plurality of oxygen inlets for creating a converging cone of oxygen for intersection with any fuel issuing from the atomiser. Such an arrangement also provides a protective wall for protecting the atomiser from the harsh environment to which the burner is exposed and simplifies the oxygen supply arrangements.

The present invention relates to a burner and relates particularly, but not exclusively, to a burner having a comparatively short flame length.
WO89/02051 discloses an oxygen-fuel burner and a method of generating an oxidising flame. The burner includes a central body with a central oxygen nozzle and at least one fuel nozzle, a casing surrounding the central body, at least one peripheral oxygen nozzle radially outside the fuel nozzle, and an oxygen chamber outside the central body, all nozzles being at least substantially parallel. The central oxygen nozzle and the peripheral oxygen nozzle are connected to different sources of oxygen such that it is possible to deliver oxygen at different pressures to each nozzle. Such an arrangement creates a rather laminar fuel and oxygen flow which is not conducive to good mixing and results in a flame length somewhat longer than might be desired. Whilst this can be an advantage in some situations, i.e. where protection of the burner tip is desirable, this burner does not lend itself to use in situations where it is desirable to create a fully developed flame at a point comparatively close to the burner tip.
Also known is a modification of the above burner in which a fuel atomiser is positioned centrally within the burner body and oxygen is used to atomise fuel oil which is then directed downstream thereof and mixed with a further stream of oxygen before being combusted. This arrangement exposes the comparatively expensive atomiser to the hostile environment associated with the application in which the burner is situated and, where metal is being melted, molten metal will often splash the atomiser thereby damaging it and reducing its effectiveness. Once damaged, such atomisers become comparatively inefficient and require replacements which can only be achieved by dismantling the burner. Clearly, this is extremely undesirable, particularly when the burner is used in a continuous process.


The system utilizes fluid pressure achieved by increasing depth as a primary component for generation of energy. The system operates by varying its depth through changes in buoyancy. The ballast changes are controlled by electronics powered by a battery charged by a generator driven by a hydraulic system. Rather than utilizing a motor driven pump to generate pressure in the hydraulic system, a piston-like cylinder is applied pressure by the change in hydrostatic pressure as depth increases and draws fluid back into the cylinder as pressure decreases. As the system sinks, outside pressure forces hydraulic fluid to power a generator that charges a battery and powers a pump to deballast. As the system rises, the lowering of ambient pressure, and other internal forces, causes the hydraulic fluid to return to its initial state, where once the ballast begins to take in fluid, the whole process will continue to repeat.

As societies continue to flourish and advance, the demand for power generation continues to increase. Currently, there is growing concern about a lack of sustainable energy sources. Electricity is currently produced in the majority by hydraulic energy conversion, carbon-based thermal energy conversion, and nuclear thermal energy conversion. The hydraulic power is the most significant source of energy.
The prior art shows a plurality of hydraulic power systems employing a buoyant element or elements that cyclically move in response to rising and falling levels of liquid within a receptable in which the buoyant element is located. Many attempts have been made to convert the energy contained in waves into electricity. Unfortunately, the construction and handling of the known systems is difficult and complex and depends on the water conditions.
Although the known hydraulic system to produce energy has served the world well and will continue to serve us well for years to come, the growing limitations and disadvantages of these sources of energy are becoming more evident.
For example, U.S. Pat. No. 5,921,082 discloses a hydro-buoyant electrical power generating plant that generates electricity from a source of hydraulic pressure. The energy that pressurizes the hydraulic fluid is derived from movements of a lever arm that has its fulcrum fixed to a stationary land mass, so that the fulcrum's position is fixed relative to the lever's opposite "movable" end. A cylinder drives the hydraulics, but the cylinder is driven by a moving "weight" attached to the lever arm that is manually pumping the cylinder. This reference requires that a fluid be externally pumped in and out in order for the object to move vertically through the water column. This motion then drives a hydraulic cylinder that then utilizes this pressure for energy generation. The reference uses a mechanical motion of buoyancy to drive a commonly used existing hydraulics system to generate power. Unfortunately, this system requires a large change in ballast weight in order to accomplish the force required for this mechanical driving of hydraulic cylinders.
Another example is US Patent Application Publication No. 2016/0208770, which discloses a power generator that generates power using buoyancy of a body located in a fluid column to generate electricity. The device includes a fluid column contained by a tank inside a piston. The piston has a hollow interior, capable of being filled with a fluid. The piston includes an inlet, operating from a filling position to a non-filling position, located on a top portion of the piston and also a rod connected to a power generator. A ballast device is connected to the piston. This invention has a cylinder that drives hydraulics, but the cylinder is driven by a moving "weight" that acts in line with the cylinder. This reference requires that a fluid be externally pumped in and out in order for the object to move vertically through the water column. This motion then drives a hydraulic cylinder that then utilizes this pressure for energy generation. The reference uses a mechanical motion of buoyancy to drive a commonly used existing hydraulics system to generate power. Unfortunately, the Berling system requires a large change in ballast weight in order to accomplish the force required for this mechanical driving of hydraulic cylinders. In order to generate any meaningful electricity, a large amount of fluid should be pushed into the hydraulic motor driving the generator. In order to push a large amount of fluid, the cylinder would need to have a large displacement. The larger the displacement, the more force required to move the cylinder. More force is only generated by adding more weight (in this case, water weight) to the system for operation. This means there is an even larger amount of energy consumption for the pumping of water into the object.
There is a need to have an energy production system that does not depend on water conditions and that does not require costly and complicated infrastructure.

Differential ambient pressure powered hydraulically driven generator battery


A safety belt retractor having a load limiting device is provided. The load limiting device comprises: a hollow spool (1) on which a webbing can be wound, a locking disk (2) having a flange (21) and a sleeve (22) attached thereto, and a torsion bar (3); the locking disk (2) can be mounted with the flange (21) on an end of the spool (1) and can extend with the sleeve (22) into a hollow chamber of the spool (1), and the spool (1) is rotatable in relation to the locking disk (2); the torsion bar (3) can be arranged in the hollow chamber of the spool (1) and is fixed on the spool (1) and on the locking disk (2) in a rotationally secured manner. The load limiting device further comprises a load limiting ring (5) with a thread (51) on the inner circumference, the load limiting ring (5) can be rotated around the sleeve (22) with the rotation of the spool (1), and the sleeve (22) is provided on its outer circumference with an engaging section (221) and with a resistance part for applying a resistance to the load limiting ring (5), the sleeve (22) having in the engaging section (221) a mating thread which matches with the thread (51) of the load limiting ring (5) and the resistance part being arranged downstream of the engaging section (221) in the axial displacement direction of the load limiting ring (5).

A safety belt retractor can comprise a safety belt tensioner and a load limiting device.
In case of collisions of a vehicle, first of all, the safety belt tensioner can tension the safety belt to eliminate the marginal space between the safety belt and the human body; and then, with the forward movement of the human body the safety belt is pulled out and then the load limiting device can reduce the tensioning strength of the safety belt so as to reduce the force applied to the passenger.
Therefore, the load limiting device of the safety belt retractor is used for providing a certain limited force to the human body. The conventional load limiting devices of the safety belt retractor employ a torsion bar. When the load reaches a certain level, the torsion bar begins to be twisted, so that the safety belt is pulled out and thereby is released, realizing a load limiting function of the safety belt. However, usually the force exerted by the load limiting device can only remain constant, i.e. keep at a basic load limiting value as defined by the torsion bar.
Nevertheless, depending on the particular types of vehicles and on the mating manners between the safety belt retractor and the airbag, it is sometimes further desired that the limited force exerted by the load limiting device of the safety belt retractor changes. For example, the load limiting value can increase or decrease, and in special cases can even become infinite.
To this end, it is currently proposed to provide an additional limited force by steel wires or blades or the like, so as to vary the limited force provided by the load limiting device of the safety belt retractor. However, it is difficult to accurately control the load limiting value provided by the load limiting devices of these prior solutions. Furthermore, these prior solutions has a space limitation, that is, when the load limiting value of the load limiting device changes, the rotation angle of the spool can only maximally reach about 300 degree, and thus the pull-out amount of the webbing wound around the spool is limited. Therefore, the safety belt retractors of these prior solutions have a great limitation when in use.

Safety belt retractor with a load limiting device and vehicle having the same

TRW AUTOMOTIVE TECHNOLOGIES (SHANGHAI) CO. LTD


An operation device for a vehicle, capable of being used in a vehicle air conditioner system. The operation device has front panels that have a light transmissive portion, and a flexible printed circuit board shaped to correspond to the arrangement of the front panels. The flexible printed circuit board includes a plurality of light emitting elements at positions respectively corresponding to the positions of the front panels. There are switching means, disposed at the rear of the printed circuit and arranged so that these switching means are operated in response to the operation of the front panels. The rear portion of the front panel can be moved together with light emitting elements in response to the operation of the front panel.

1. Field of the invention
The present invention relates to an operation device for a vehicle air conditioner and, in particular, to an operation device including an illumination type operation switch.
2. Related art
Conventionally, in an operation device for a vehicle air conditioner, there generally are light transmissive front panels with light being projected from the back surfaces of the respective front panels to enhance the visibility of the operation device.
This type of an operation device for a vehicle air conditioner is structured such that lights from a plurality of light emitting elements of high luminance are guided to the central portions of the back surfaces of the respective front panels by lightguides each having a high light-transmittance, and The operation device also has switch means, each having an electric function which are disposed in the peripheral edge portions of the back surfaces of the respective front panels. A switch of this illumination type, as disclosed in Japanese Patent Publication No. 6-283077 of Heisei or Japanese Patent Publication No. 5-325703 of Heisei, illustrates a structure in which light emitting elements are respectively disposed in the central portions of the back surfaces of the respective front panels, while switch means are respectively disposed in the peripheral edge portions of the back surfaces of the respective front panels.
However, in the above-mentioned conventional operation device for a vehicle air conditioner, it is difficult to achieve both ease of operation and accurate visibility of the switches. The above-mentioned various kinds of illumination type switches are structured such that a light guide for enhancing the visibility of a light emitting element is disposed in the central portion of the back surface of each front panel. Thus, the function of the operation switch is displayed substantially in the central portion of the front panel. Moreover, the illumination of the front panel in the portion where the function of the operation switch is displayed works effectively.
However, by placing the illuminating portion of the switch in the center portion of the front panel, the switch means, which is allowed to perform its switching operation when the front panel is operated, cannot be placed in the center portion of the front panel. The switch means must be disposed in the peripheral edge of the back surface of the front panel. Therefore, when the front panel is operated, a force to incline the front panel can be applied to the front panel.
Moreover, it is difficult to operate device because the relationship between the illuminating elements and the operational switches, are reversed. On the other hand when the switch is placed in the central portion of the front panel, the operation of the switch means can be truly improved, but the illumination efficiency of the front panel is lowered, thus impairing the superiority of the operation switch of an illumination type.

Operation device for vehicle air conditioner

Kabushiki Kaisha Tokai Rika Denki Seisakusho


The freezing of water pipes in a dwelling in cold climates is prevented by separating some of the cold water delivered to the dwelling and conducting that separated cold water into heat exchanging relationship with a hot water tank. The thus-warmed water is caused to flow through a cold water main of the dwelling whenever an outlet is automatically periodically opened by means of a temperature sensing valve unit connected to the outlet. The water flowing through the cold water main warms the water in branch lines and at the outlet to prevent that water from freezing.

The present invention relates to the prevention of water pipe freeze-up in a dwelling.
During cold weather conditions, it is possible for one or more water pipes in a dwelling to freeze and then burst, whereby expensive repairs to the pipes and the dwelling itself may be required.
In moderate climates where the minimum outside temperature only rarely extends below freezing, dwellings might not be provided with an indoor valve for shutting-off the supply of water to an outdoor faucet. In such a case, the risk of freezing can be avoided by placing on the outdoor faucet an automatically actuable valve unit which senses the temperature of water at the faucet and opens to emit a water flow whenever the temperature approaches the freezing point. In this way, warmer ground water from within the dwelling will reach the faucet, whereupon the temperature sensor will cause the valve unit to close. Accordingly, the valve unit will open and close periodically during periods of cold weather, in order to prevent the water from freezing at the faucet. A temperature sensitive valve unit of this type is disclosed for example in the inventor's U.S. Pat. No. 4,657,038 issued Apr. 14, 1987, and can be purchased from KDL Technologies, P.O. Box 1375, Alachua, Fla. 32615 under the name FREEZE/GUARD.TM..
While the use of such a temperature sensitive valve unit successfully functions to prevent pipe freeze-up in moderate climates, it may not be as successful in colder climates. That is, in colder climates (e.g., where the ground water temperature can be expected to fall below 42.degree. F.), the water temperature within certain pipes within the dwelling may fall below freezing despite the use of a temperature sensitive valve unit. While this can happen in the case of dwellings which are occupied, it is especially problematic in the case of homes which are unoccupied during the winter. In the latter case, it is necessary to drain the water pipes which is a time-consuming and often difficult procedure.
It is, therefore, an object of the invention to prevent water pipe freeze-up in any climate, even in the case of unoccupied dwellings in cold climates.

Methods and apparatus for prevention of water pipe freeze-up in a dwelling


Deadblow hammers capable of minimizing or eliminating recoils when the hammers impact their targets are discussed which have easy access anti-recoil chambers and which have open sockets for receiving handles that extend the length of the hammerhead body. These hammers incorporate filler materials, which function to negate the effects of the hammer recoils, with improved filling port(s) for filling the filler materials. Golf clubs with anti-recoil chamber and insert elements are also discussed.

It is a well-known principle that every action has is an equal and opposite reaction (Newton's Third Law). Thus, for a hammer, when the impact surface of the hammerhead impacts a target, the hammer is jolted backwards due to the reaction caused by the hammerhead striking its target. This opposite reaction is commonly referred to as hammer recoil.
For minimizing or eliminating hammer recoils, which cause vibrations and injuries to the user, numerous hammers were invented. Broadly speaking, these hammers utilize some form of inserts placed in a hollow chamber within the hammerhead, or within a separate hollow body having a hollow chamber attached to the hammerhead. The inserts are configured to move from a rear surface of the hollow chamber to a front surface of the hollow chamber. Accordingly, when the hammer moves in a first direction to impact its target, the inserts are pushed by the rear surface of the hollow chamber to move in the same first direction.
As the impact surface of the hammerhead impacts a target and starts its recoil in a second direction, the inserts still move in the first direction within the hollow chamber and impact the front surface of the hollow chamber, in the first direction. The inserts impacting against the front surface of the hollow chamber thus cancel the recoil in total or substantially. The amount of cancellation depends, in part, on the weight percentage of the inserts compared to the weight of the hammerhead. Without being restricted to any particular theory, the deadblow impact or feel to the user also depends on the distance the insert travels before it impacts the front surface, which will influence how far the hammer recoils before the insert impacts the front surface to cancel out the effect.
U.S. Pat. No. 6,234,048 to Carmien discloses a non-recoil hammer, with a hammerhead that has an open socket for receiving a separate hollow canister. The hollow canister connects to a tool handle and contains a relatively high mass moveable filler material in a hollow chamber, such as steel shot pellets. The hollow canister is received within the open socket to form a completed hammer. Due to the two-piece design, the hammer is more complicated and costly to manufacture.
U.S. Pat. No. 5,916,338 to Bergkvist et al. discloses a hammer having a hammerhead with an impact element and a cavity at least partially filled with particulate material, such as steel shot, so as to dampen the recoil of the hammer. The impact element is forged with the head as a single piece or may be formed as a separate part that is connected to the head by welding. However, since the cavity extends the full length of the hammerhead, the handle cannot attach to the hammerhead by passing through central portion of the hammerhead, but is attached via partial through hole at the central portion of the hammerhead. This makes the handle more susceptible to slippage or separation from the hammerhead. Furthermore, because of the cavity, a conventional handle with a split end for wedging the handle with a wedge is not useable with the disclosed hammerhead.
U.S. Pat. No. 4,039,012 to Cook discloses a non-rebound hammer having a hammerhead portion with forwardly and rearwardly facing metallic impact surfaces. The head portion contains a hollow cylindrical core for receiving a quantity of pellets, such as small lead shots. The hammerhead also contains a core hole for receiving a handle rod. The handle rod and the hammerhead are then co-molded with an encasement. Due to the co-molded configuration, the entire hammer must be discarded when damage is done to the handle.
U.S. Pat. No. 2,604,914 to Kahlen discloses a hammerhead having a rebound-preventing means. The hammerhead has a body with a striking head at each end of the body. Each striking head is formed integrally with the body, or alternatively it may be secured to the body as a separate piece. A chamber is formed in the body immediately behind the striking heads. The chamber contains irregularly shaped particles 26, as shown in FIG. 3 of the '914 patent. The particles almost completely fill the chamber, with the total weight of the particles dependent on the recoil quality of the striking head, the size of the hammer, and the weight of the head. Due to the lengthwise chamber, a ferrule is used to connect a handle to the body. This makes the body unnecessarily bulky.
There is therefore a need for a non-recoil hammer or deadblow hammer that minimizes or negates the effects of hammer recoils and that do so without the shortcomings of prior art deadblow hammers. Additionally, there is also a need for a method of making the desired deadblow hammer.


A pre-paid purchasing system comprises a pre-paid purchasing card and a plurality of single use access codes on the card. Each access code is usable to authorize one payment of an amount which is subtracted from the pre-paid amount of the card. After use, an access code becomes null and void. Moreover, a method for managing purchases of goods and services from the Internet, mail-order catalogs, any merchant, etc. is proposed.

This invention relates to a pre-paid purchasing system and a method for activating a transaction for purchasing goods or services from the Internet, mail-order catalogues, or other merchants. The purchasing system comprises a pre-paid card with a multiple code system, with access codes and security codes. Advantageously, access codes and security codes are stored or printed on two separate cards and the codes from each card working in conjunction with each other.
Merchants selling their products to the consumers commonly accept credit cards for the purchasing of their goods. Consumers often use their credit cards for all their purchasing needs, be it from the Internet, mail-order catalogues, or any merchant selling goods or services, who except credit cards.
Credit cards are designed to create a convenient method for the consumers to make purchases, but there are some major disadvantages to having and using a credit card. For example, when a person has their credit card stolen or loses their credit card. The owner of the lost, or stolen credit card has to call the financial institution of that credit card to report and cancel the lost, or stolen credit card. After calling the financial institution and cancelling the lost or stolen credit, that person has to wait for a new credit card to arrive from the financial institution. Which creates an inconvenience to the cardholder, if that lost or stolen credit card is their only credit card. Also, someone other than the owner of the lost or stolen credit card, making a purchase on the lost or stolen credit card, before the owner of the lost or stolen credit card can call the financial institution of that credit card to report their credit card has been lost or stolen. If a charge is made to the lost or stolen credit card, the owner of the lost or stolen credit card has to prove to the financial institution, they didn't make that particular charge.
There is no secure system to protect the consumer from having their credit card stolen and used by the person who has stolen the credit card, or from having their credit card number stolen and cloned, which can then be sold to interested parties. A high security risk area for consumers using their credit card is the Internet. When consumers enter their credit card number for the purchase they are making, their credit card number can be intercepted by a computer hacker. The stolen credit card number can be used by the person who intercepted the number, or the credit card numbers can be cloned and sold to interested parties throughout the world, and used to make numerous purchases illegally. Long before the owner of the credit card becomes aware of what has happened. The theft of credit card numbers from the Internet has long been a problem which causes a great inconvenience to the card holder. The same holds true for mail-order catalogues. Consumers using their credit card when making a purchase from mail-order catalogues, are also at risk of having their credit card number stolen and used by someone other than the owner of the credit card.
Also, some consumers who use credit cards, are at risk of spending money they don't have. With a credit card, you buy now pay later, which often leads to some consumers spending more money than they have. Which makes it very difficult for that consumer to pay their monthly credit card statement, and possibly go into debt.
On the other hand there are consumers who are limited to using cash, a money order, or writing a personal check to make a purchase, because they are without a credit card. Also, there are financial institutions that offer people with a bad credit history, credit cards, but in order for a person to obtain a credit card from these financial institutions, a person must make a deposit of money in to an account at that particular financial institution. This type of credit card is referred to as a secured credit card. With secured credit cards, comes a very high interest rate, which the person obtaining a secured credit card has to accept if they want to have a credit card.


A system to control a threading operation includes a first tubular and a second tubular, wherein the first tubular and the second tubular include corresponding thread profiles. The system further includes a drive assembly configured to rotate the second tubular with respect to the first tubular, wherein vertical and rotation movements of the drive assembly are controllable through a drive assembly controller, and wherein the drive assembly controller is configured to operate in a threading mode when the second tubular is threaded with the first tubular.

1. Field of the Disclosure
Embodiments disclosed herein relate generally to tubular connections. More specifically, embodiments of the present disclosure relate to a method and apparatus for controlling the rate of assembly of tubulars to maintain a rate within a selected set of parameters during make-up.
2. Background Art
Drilling wells in subsurface formations for oil and gas wells is expensive and time consuming. Formations containing oil and gas are typically located thousands of feet below the earth's surface. Therefore, thousands of feet of rock and other geological formations must be drilled through in order to establish production. Casing joints, liners, and other oilfield tubulars are frequently used to drill, complete, and produce wells. For example, casing joints may be placed in a wellbore to stabilize and protect a formation against high wellbore pressures (e.g., wellbore pressures that exceed a formation pressure) that could otherwise damage the formation. Casing joints are sections of pipe (e.g., steel or titanium), which may be coupled in an end-to-end manner by threaded connections, welded connections, or any other connection mechanisms known in the art.
It should be understood that certain terms are used herein as they would be conventionally understood, particularly where threaded tubular joints are connected in a vertical position along their central axes such as when making up a pipe string for lowering into a well bore. Typically, in a male-female threaded tubular connection, the male component of the connection is referred to as a "pin" member and the female component is called a "box" member. As used herein, "make-up" refers to engaging a pin member into a box member and threading the members together through torque and rotation.
Referring initially to FIG. 1, a rotary drilling system 10 including a land-based drilling rig 11 is shown. While drilling rig 11 is depicted in FIG. 1 as a land-based rig, it should be understood by one of ordinary skill in the art that embodiments of the present disclosure may apply to any drilling system including, but not limited to, offshore drilling rigs such as jack-up rigs, semi-submersible rigs, drill ships, and the like. Additionally, although drilling rig 11 is shown as a conventional rotary rig, wherein drillstring rotation is performed by a rotary table, it should be understood that embodiments of the present disclosure are applicable to other drilling technologies including, but not limited to, top drives, power swivels, downhole motors, coiled tubing units, and the like.
As shown, drilling rig 11 includes a mast 13 supported on a rig floor 15 and lifting gear comprising a crown block 17 and a traveling block 19. Crown block 17 may be mounted on mast 13 and coupled to traveling block 19 by a cable 21 driven by a draw works 23. Draw works 23 controls the upward and downward movement of traveling block 19 with respect to crown block 17, wherein traveling block 19 includes a hook 25 and a swivel 27 suspended therefrom. Swivel 27 may support a Kelly 29 which, in turn, supports drillstring 31 suspended in wellbore 33. Typically, drillstring 31 is constructed from a plurality of threadably interconnected sections of drill pipe 35 and includes a bottom hole assembly ("BHA") 37 at its distal end.
As is well known to those skilled in the art, the weight of drillstring 31 may be greater than the optimum or desired weight on bit 41 for drilling. As such, part of the weight of drillstring 31 may be supported during drilling operations by lifting components of drilling rig 11. Therefore, drillstring 31 may be maintained in tension over most of its length above BHA 37. Furthermore, because drillstring 31 may exhibit buoyancy in drilling mud, the total weight on bit may be equal to the weight of drillstring 31 in the drilling mud minus the amount of weight suspended by hook 25 in addition to any weight offset that may exist from contact between drillstring 31 and wellbore 33. The portion of the weight of drillstring 31 supported by hook 25 is typically referred to as the "hook load" and may be measured by a transducer integrated into hook 25.
Generally, threaded tubular products (typically casing, but may apply to drill-pipe, drill-collars, etc, referred to as tubulars or joints) may be assembled, or made-up, on drilling rigs by holding a lower joint fixed in the rotary table and by turning and lowering an upper joint into the lower joint. The upper joint may be turned by using the topdrive and lowering may be accomplished using the drawworks. Alternatively, already made-up tubulars may be unthreaded, also known as break-out, to disassemble a tubular string.
While "spinning" the two joints together (while the threads are engaging), torque may be limited to a fraction of a desired connection torque until the threads have fully engaged. Once the threads have fully engaged, the rotating torque may rise to the spinning torque limit and the rotation may stall. To complete the connection process, the torque limit is then increased to a final desired connection value, at which point rotation may re-commence and stall again at the final desired torque value, or make-up torque, for the connection.
Once the threads on the upper and lower joints are engaged, a drilling operator must lower the tubular at a correct rate to successfully spin the joints together. If the joint is lowered too quickly or too slowly, the threading process may stall out prematurely, or damage the threads. To lower at the "correct" rate while the threads are spinning together, the drilling operator may watch the indicated hookload and may modulate the drawworks speed by hand. If the lowering speed is too great, then the hookload decreases and the drilling operator may slow down, and vice-versa. In addition, the drilling operator is responsible for watching the rig floor and the tubular joint to ensure the process is safely and properly conducted.
While lowering the first tubular to be stabbed into the second tubular, very accurate control of the lowering speed may be required. Typically, the drilling operator may use a joystick that is scaled to allow a maximum operating speed of the drawworks to be achieved at a full travel of the joystick. The drilling operator may enter a reduced maximum speed, which would achieve the fine control, but may then need to manually enter a faster speed in order to manipulate the assembled tubulars after threading is completed.
Accordingly, there exists a need for an improved control system which reduces drilling operator intervention during threading and unthreading of tubular connections.

Electronic threading control apparatus and method


An optical transmission apparatus is provided in which high optical output power is secured in an optical transmitter, the fine adjustment of the optical axis is unnecessary, and the propagation range of the optical output signal can be adaptively changed. A diffusing liquid lens includes a first liquid and a second liquid containing a scattering material that scatters light, and the curvature of the boundary surface between the first and the second liquids is changed according to the control voltage applied from a controlling unit. A first optical signal outputted from a light emitting device is diffused in the first liquid, and emitted as a second optical signal having a spread angle corresponding to the curvature of the boundary surface and a substantially uniform radiant intensity distribution.

1. Field of the Invention
The present invention relates to an optical transmitter, and more particularly, to an optical transmitter that transmits an optical signal to an optical receiver through free space.
2. Description of the Background Art
Conventionally, an optical space communication that transmits an optical signal through free space has been known. Since light which serves as the transmission medium in the optical space communication has directivity, it is necessary to adjust the optical axis between the optical transmitter and the optical receiver.
FIG. 21 is a view of an example of an optical space transmission apparatus having an optical axis adjusting function.
An optical transmitter 101 and an optical receiver 102 respectively have optical axis adjusting mechanisms 103a and 103b that are rotatable about a horizontal axis and a vertical axis. To enable the optical communication between the optical transmitter 101 and the optical receiver 102, the optical axis adjusting mechanisms 103a and 103b are adjusted so that the optical axes of the optical transmitter 101 and the optical receiver 102 substantially coincide with each other.
For example, when the optical receiver 102 is disposed at a point a, it is necessary for the optical axes of the optical transmitter 101 and the optical receiver 102 only to be adjusted so that the light receiving surface of the optical receiver 102 is included in a propagation plane Pa of the light emitted from the optical transmitter 101. On the other hand, when the optical receiver 102 is disposed at a point b, it is necessary to adjust the optical axes so that the light receiving surface of the optical receiver 102 is included in a propagation plane Pb smaller than the propagation plane Pa at the point a.
Thus, in the optical space transmission apparatus shown in FIG. 21, although the optical axis adjustment is easy when the distance between the optical transmitter 101 and the optical receiver 102 is comparatively long, the shorter the distance is, the more difficult the optical axis adjustment is.
Accordingly, to solve this problem, an optical space transmission apparatus as described below is known (see, for example, Japanese Examined Patent Publication No. 06-83145 (FIG. 1)).
FIG. 22 is a view of the schematic structure of a conventional optical transmission apparatus.
With reference to FIG. 22, an optical transmitter 201 and an optical receiver 202 are disposed so as to be opposed to each other. The optical transmitter 201 has: a transmission circuit unit 203; a light emitting device 204 that converts an electrical signal into an optical signal; a zoom lens 205; a drive controlling unit 206 that outputs a control signal for adjusting the zoom ratio of the zoom lens 205; and an optical axis adjusting mechanism 207a that adjusts the optical axes. The optical receiver 202 has an optical axis adjusting mechanism 207b.
The optical axes of the optical transmitter 201 and the optical receiver 202 are adjusted by using the optical axis adjusting mechanisms 207a and 207b like the example of FIG. 21. In addition, some of the lens elements constituting the zoom lens 205 move backward and forward along the optical axis according to the control signal outputted from the drive controlling unit 206. Since the movement of the lens elements changes the spread angle of the optical signal, the area of the propagation plane of the optical signal emitted from the optical transmitter 201 changes with respect to the light receiving surface of the optical receiver 202.
Therefore, even when the distance between the optical transmitter 201 and the optical receiver 202 is comparatively short, the adjustment of the optical axes of the optical transmitter 201 and the optical receiver 202 can be facilitated by adjusting the zoom ratio of the zoom lens 205 so that the spread angle of the emitted light is increased.
However, in the optical space transmission apparatus, from the viewpoint of user safety, the optical output power is restricted. Therefore, in actuality, optical communication cannot be performed with the spread angle being increased by the zoom lens 205.
Specifically, when the optical signal outputted from the light emitting device 204 is emitted through the zoom lens 205, the light source viewed from the exit plane of the zoom lens 205 is assumed to be the point source. For example, when the light emitting device 204, which is operable to emit light of a wavelength λ of 850 nm, outputs an optical signal through the zoom lens 205, the maximum optical output power satisfied the eye safety is determined to be 0.78 mW according to the IEC60825-1 standard.
The determined optical output power is not sufficient for performing optical communication. Therefore, to efficiently use the limited optical output power, it is necessary to operate the optical axis adjusting mechanisms 207a and 207b to thereby make the optical axes of the optical transmitter 201 and the optical receiver 202 coincide with each other and then, make an adjustment to reduce the spread angle of the emitted light again by the zoom lens 205.
Further, since the substantial light receiving sensitivity of the optical receiver 202 decreases as the communication speed increases, it is desirable that the optical output power outputted from the optical transmitter be as high as possible.