The present invention provides propofol prodrugs, methods of making propofol prodrugs, pharmaceutical compositions of propofol prodrugs and methods of using propofol prodrugs and pharmaceutical compositions thereof to treat or prevent diseases or disorders such as migraine headache pain and post-chemotherapy or post-operative surgery nausea and vomiting.

Propofol (2,6-diisopropylphenol), (1), is a low molecular weight phenol that is widely used as an intravenous sedative-hypnotic agent in the induction and maintenance of anesthesia and/or sedation in mammals. The advantages of propofol as an anesthetic include rapid onset of anesthesia, rapid clearance, and minimal side effects (Langley et al., Drugs 1988, 35, 334-372). Propofol may mediate hypnotic effects through interaction with the GABAA receptor complex, a hetero-oligomeric ligand-gated chloride ion channel (Peduto et al., Anesthesiology 1991, 75, 1000-1009).

Propofol is rapidly metabolized in mammals with the drug being eliminated predominantly as glucuronidated and sulfated conjugates of propofol and 4-hydroxypropofol (Langley et al., Drugs 1988, 35, 334-372). Propofol clearance exceeds liver blood flow, which indicates that extrahepatic tissues contribute to the overall metabolism of the drug. Human intestinal mucosa glucuronidates propofol in vitro and oral dosing studies in rats indicate that approximately 90% of the administered drug undergoes first pass metabolism, with extraction by the intestinal mucosa accounting for the bulk of this presystemic elimination (Raoof et al., Pharm. Res. 1996, 13, 891-895). Because of its extensive first-pass metabolism, propofol is administered by injection or intravenous infusion and oral administration has not been considered therapeutically effective.
Propofol has a broad range of biological and medical applications, which are evident at sub-anesthetic doses and include treatment and/or prevention of intractable migraine headache pain (Krusz et al., Headache 2000, 40, 224-230; Krusz, International Publication No. WO 00/54588). Propofol, when used to maintain anesthesia, causes a lower incidence of post-operative nausea and vomiting ("PONV") compared to common inhalation anesthetic agents and numerous controlled clinical studies support the anti-emetic activity of propofol (Tramer et al., Br. J. Anaesth. 1997, 78, 247-255; Brooker et al., Anaesth. Intensive Care 1998, 26, 625-629; Gan et al., Anesthesiology 1997, 87, 779-784). Propofol has also been shown to have anti-emetic activity when used in conjunction with chemotherapeutic compounds (Phelps et al., Ann. Pharmacother. 1996, 30, 290-292; Borgeat et al., Oncology 1993, 50, 456-459; Borgeat et al., Can. J Anaesth. 1994, 41, 1117-1119; Tomioka et al., Anesth. Analg. 1999, 89, 798-799). Nausea, retching and/or vomiting induced by a variety of chemotherapeutic agents (e.g., cisplatin, cyclophosphamide, 5-fluorouracil, methotrexate, anthracycline drugs, etc.) has been controlled by low-dose propofol infusion in patients refractory to prophylaxis with conventional anti-emetic drugs (e.g., serotonin antagonists and corticosteroids).
Propofol has also been used to treat patients with refractory status epilepticus (Brown et al., Pharmacother. 1998, 32, 1053-1059; Kuisma et al., Epilepsia 1995, 36, 1241-1243; Walder et al., Neurology 2002, 58, 1327-1332; Sutherland et al., Anaesth. Intensive Care 1994, 22, 733-737). Further, the anticonvulsant effects of propofol have also been demonstrated in rat efficacy models at sub-anesthetic doses (Holtkamp et al., Ann. Neurol. 2001, 49, 260-263; Hasan et al., Pharmacol. Toxicol. 1994, 74, 50-53).
Propofol has also been used as an antioxidant (Murphy et al., Br. J. Anaesth. 1992, 68, 613-618; Sagara et al., J. Neurochem. 1999, 73, 2524-2530; Young et al., Eur. J. Anaesthesiol. 1997, 14, 320-326; Wang et al. Eur. J. Pharmacol. 2002, 452, 303-308). Propofol, at doses typically used for surgical anesthesia, has observable antioxidant effects in humans (De la Cruz et al., Anesth. Analg. 1999, 89, 1050-1055). Pathogenesis or subsequent damage pathways in various neurodegenerative diseases involve reactive oxygen species and accordingly may be treated or prevented with antioxidants (Simonian et al., Pharmacol. Toxicol. 1996, 36, 83-106). Examples of specific neurodegenerative diseases which may be treated or prevented with anti-oxidants include, but are not limited to, Friedrich's disease, Parkinson's disease, Alzheimer's disease, Huntington's disease, amyotrophic lateral sclerosis ("ALS"), multiple sclerosis ("MS"), Pick disease, inflammatory diseases and diseases caused by inflammatory mediators such as tumor necrosis factor (TNF) and IL-1.
A significant problem with the formulation and use of propofol is poor water solubility. Accordingly, propofol must be specially formulated in aqueous media using solubilizers or emulsifiers (Briggs et al., Anaesthesia 1982, 37, 1099-1101). For example, in a current commercial product (Diprivan®, Astra-Zeneca) an oil-in-water emulsion (the emulsifier is the lecithin mixture Intralipid®), is used to formulate propofol (Picard et al., Anesth. Analg. 2000, 90, 963-969). Unfortunately, the oil-in-water emulsion formulation causes discomfort and pain at the site of injection.
One potential solution to the poor water solubility of propofol that avoids the use of additives, solubilizers or emulsifiers and the attendant injection site pain, is a water-soluble, stable propofol prodrug that is converted to propofol in vivo. (Hendler et al., International Publication No. WO 99/58555; Morimoto et al., International Publication No. WO 00/48572; Hendler et al., U.S. Pat. No. 6,254,853; Stella et al., United States Patent Application No. US2001/0025035; Hendler, U.S. Pat. No. 6,362,234; Hendler, International Publication No. WO 02/13810; Sagara et al., J. Neurochem. 1999, 73, 2524-2530; Banaszczyk et al., Anesth. Analg. 2002, 95, 1285-1292; Trapani et al., Int. J. Pharm. 1998, 175, 195-204; Trapani et al., J. Med. Chem. 1998, 41, 1846-1854; Anderson et al., J. Med. Chem. 2001, 44, 3582-3591; Pop et al., Med. Chem. Res. 1992, 2, 16-21). A significant problem with these existing propofol prodrugs is their high stability in vivo. This stability prevents release of therapeutically significant concentrations of propofol, particularly when the prodrug is orally administered.
Accordingly, there is a need for propofol prodrugs, which are sufficiently labile under physiological conditions to provide therapeutically effective concentrations of propofol, particularly, when the prodrug is orally administered.

Prodrugs of propofol, compositions and uses thereof


A method of making a magnetic tunnel junction device is disclosed. The magnetic tunnel junction device includes a magnetic tunnel junction stack and an electrically non-conductive spacer in contact with a portion of the magnetic tunnel junction stack. The spacer electrically insulates a portion of the magnetic tunnel junction stack from an electrically conductive material used for a via that is in contact with the magnetic tunnel junction stack and a top conductor. The spacer can also prevent an electrical short between a bottom conductor and the top conductor. The spacer can prevent electrical shorts when the magnetic tunnel junction stack and a self-aligned via are not aligned with each other.

An magnetoresistance random access memory (MRAM) includes an array of memory cells. Each memory cell is a magnetic tunnel junction device. The magnetic tunnel junction device operates on the principles of spin tunneling. There are several types of magnetic tunnel junction devices including two prominent types, tunneling magnetoresistance (TMR) and giant magnetoresistance (GMR). Both types of devices comprise several layers of thin film materials and include a first layer of magnetic material in which a magnetization is alterable and a second layer of magnetic material in which a magnetization is fixed or "pinned" in a predetermined direction. The first layer is commonly referred to as a data layer or a sense layer; whereas, the second layer is commonly referred to as a reference layer or a pinned layer. The data layer and the reference layer are separated by a very thin tunnel barrier layer. In a TMR device, the tunnel barrier layer is a thin film of a dielectric material (e.g. silicon oxide SiO2). In contrast, in a GMR device, the tunnel barrier layer is a thin film of an electrically conductive material (e.g. copper Cu).
Electrically conductive traces, commonly referred to as word lines and bit lines, or collectively as write lines, are routed across the array of memory cells with a memory cell positioned at an intersection of a word line and a bit line. The word lines can extend along rows of the array and the bit lines can extend along columns of the array, or vice-versa. A single word line and a single bit line are selected and operate in combination to switch the alterable orientation of magnetization in the memory cell located at the intersection of the word line and the bit line. A current flows through the selected word and bit lines and generates magnetic fields that collectively acts on the alterable orientation of magnetization to cause it to switch (i.e. flip) from a current state (i.e. a logic zero "0") to a new state (i.e. a logic "1").
One problem in prior magnetic tunnel junction devices is that the electrically conductive materials that are used for the write lines can become shorted to each other and/or can cause a short between the data and reference layers. As a result, the short causes a resistance of the prior magnetic tunnel junction device to be too low and therefore the state of the alterable orientation of magnetization cannot be sensed by measuring a resistance across the magnetic tunnel junction device or by sensing a magnitude of current flow through the magnetic tunnel junction device. Consequently, the short is a defect that renders the magnetic tunnel junction device inoperable.
In FIG. 1, a prior magnetic tunnel junction device 200 includes a magnetic tunnel junction stack 230 that is crossed by and positioned between a column conductor 201 and a row conductor 213. A current lx flowing in the column conductor 201 generates a magnetic field Hy and a current ly flowing in the row conductor 213 generates a magnetic field Hx. The combined effect of the magnetic fields (Hy, Hx) acting on the alterable orientation of magnetization causes the alterable orientation to flip if a combined magnitude of the magnetic fields (Hy, Hx) is of a sufficient magnitude.
One disadvantage of the prior magnetic tunnel junction device 200 is that shorts created during a manufacturing of the device can significantly reduce manufacturing yields. For example, if during the manufacturing of the prior magnetic tunnel junction device 200, some of the material for the column conductor 201 comes into contact with the row conductor 213 or comes into contact with a side 230c of the magnetic tunnel junction stack 230, then the magnetic tunnel junction device 200 is defective due to a short circuit.
In FIG. 2, the prior magnetic tunnel junction stack 230 can include a pinned layer 209 of a magnetic material (e.g. made from nickel iron NiF) and including a pinned orientation of magnetization (not shown), a tunnel barrier layer 207 (e.g made from aluminum oxide Al2O3 for a TMR device), and a data layer 205 of a magnetic material (e.g. made from nickel iron cobalt NiFeCo) and including an alterable orientation of magnetization (not shown). During manufacturing, a pattern formed by a mask layer 220 is formed on a dielectric layer 221. Ideally, as depicted by dashed lines I, the pattern formed by the mask 220 would be perfectly aligned with the magnetic tunnel junction stack 230. However, in reality, there are errors introduced by the machines and the fabrication processes used to manufacture the prior magnetic tunnel junction device 200. As a result, an actual misalignment depicted by dashed lines A can occur.
In FIG. 3, the dielectric layer 221 is etched through the mask layer 220 to form a via 233 in the dielectric layer 221. Due to the misalignment, the via 233 extends beyond a top portion of the magnetic tunnel junction stack 230 and exposes a side portion 233m of the magnetic tunnel junction stack 230.
In FIG. 4a, during a metal deposition step, an electrically conductive material 235 fills in the misaligned via 233 including those portions in the side portion 233m which creates a short 235s between the magnetic tunnel junction stack 230 and the row conductor 213. In FIG. 4b, the column conductor 201 is formed on the electrically conductive material 235 resulting in a short 235t between the row and column conductors (213, 201) and the magnetic tunnel junction stack 230.
Consequently, there is a need for a method of making a magnetic tunnel junction device that reduces the potential for electrical shorts due to misalignment of a via relative to a magnetic tunnel junction stack.

Method of making a magnetic tunnel junction device

Hewlett-Packard Development Company, LP.


A plasma display panel displaying grayscales by a combination of brightness weights of a plurality of subfields in a frame. A peak subfield index of a current frame is generated based on a highest grayscale value detected from an input image data of the current frame, wherein the peak subfield index contains information of at least one subfield that is not used in the current frame. At least one period of reset, address, and sustain periods of the at least one subfield that is not used in the current frame is removed in response to a control signal and the peak subfield index of the current frame. The control signal is generated based on a comparison of a peak subfield index of a previous frame that has been delayed by one frame and the peak subfield index of the current frame.

1. Field of the Invention
The present invention relates to a driving apparatus for a plasma display panel and an image processing method thereof, and in particular, to a driving apparatus for plasma display panel and an image processing method thereof that results in reduced power consumption without flickers.
2. Description of the Related Art
Recently, flat panel displays, such as a liquid crystal display (LCD), a field emission display (FED), and a plasma display panel (PDP) have been actively developed. The PDP is advantageous over other flat panel displays in regard to its high luminance, high luminous efficiency, and wide viewing angle.
A PDP displays an image by activating phosphor by ultraviolet (UV) rays generated by a discharge of an inert gas, e.g., He+Ne, He+Xe, or He+Ne+Xe. Such a PDP is classified into a direct current (DC) type or an alternating current (AC) type according to patterns of waveforms of driving voltages applied thereto and discharge cell structures thereof.
The DC PDP displays an image by applying a predetermined driving waveform to electrodes exposed to a discharge space. Since a DC PDP allows a direct current to flow through the discharge space while a voltage is applied to the exposed electrodes, such a DC PDP problematically requires a resistance for limiting the current. On the other hand, the AC PDP has electrodes covered with a dielectric layer that forms a capacitor to limit the current and protects the electrodes from the impact of ions during discharge. Accordingly, an AC PDP typically has a longer lifetime than a DC PDP.
FIG. 1 is a partial perspective view of an AC PDP.
As shown in FIG. 1, a conventional AC PDP includes scan and sustain electrodes 4 and 5 formed on an upper substrate 1 and address electrodes 8 formed on a lower substrate 6. Each of the scan and sustain electrodes 4 and 5 includes a transparent electrode and a metal bus electrode. The metal bus electrode has narrower width than the transparent electrode, and is disposed at a side of the transparent electrode.
The transparent electrode is usually formed of indium-tin-oxide (ITO). The metal bus electrode is usually formed of metal such as chrome Cr, and is formed on the transparent electrode so as to reduce a voltage drop by the transparent electrode having high resistance.
An upper dielectric layer 2 and a protective layer 3 are formed on the upper substrate 1 having the scan and sustain electrodes 4 and 5 formed thereon. Wall charges generated by a plasma discharge are accumulated on the upper dielectric layer 2. The protective layer 3 protects the upper dielectric layer 2 from damages caused by sputtering during the plasma discharge, and enhances emission efficiency of secondary electrons.
A lower dielectric layer 7 and barrier ribs 9 are formed on the lower substrate 6 on which the address electrodes 8 are formed, and a phosphor layer 10 is formed on the lower dielectric layer 7 and a surface of the barrier ribs 9. The address electrodes 8 are formed in a direction crossing the scan and sustain electrodes 4 and 5. The barrier ribs 9 are formed linearly or in a lattice pattern (not shown), and prevents UV rays and visible light generated by a discharge from leaking into adjacent discharge cells. The phosphor layer 10 is excited by the UV rays generated by a plasma discharge, and produces red, green, or blue color. An inert gas mixture is contained in a discharge space 11 formed by the upper substrate 1, the lower substrate 6, and the barrier ribs 9. A discharge cell (which may also be referred to as a cell) 12 is formed at an intersection region of the address electrode 8 and a pair of one scan electrode 4 and one sustain electrode 5 that are disposed in parallel.
FIG. 2 illustrates an electrode arrangement of a PDP.
Referring to FIG. 2, address electrodes A1 to Am are disposed in a column direction. Scan electrodes Y1 to Yn and sustain electrodes X1 to Xn are disposed in a row direction in pairs. Discharge cells are formed in an m×n matrix format, wherein a discharge cell 12 is formed at each area where one of the address electrodes A1-Am crosses a pair of the scan and sustain electrodes Y1-Yn and X1-Xn.
The PDP is driven by frames, where each frame is divided into a plurality of subfields having different numbers of light emitting periods in order to realize a time-division grayscale display. Each subfield includes a reset period for initializing every discharge cell, an address period for selecting turn-on cells (i.e., cells to be turned on), and a sustain period for realizing grayscales according to the number of discharges in the turn-on cells.
That is, as shown in FIG. 3, each of a plurality of subfields includes a reset period, an address period, and a sustain period. FIG. 3 illustrates an exemplary subfield arrangement wherein one frame includes eight subfields so as to realize 256 grayscales. The reset period and the address period of the subfields are of the same length independent of the subfields. However, the sustain periods increase in ratios of 2n (n=0,1,2,3,4,5,6,7) according to subfields, so as to realize grayscales.
For example, in order to realize a grayscale of level 3 at a specific discharge cell, the specific cell is discharged during first and second subfields SF1 and SF2. In addition, in order to realize a grayscale of level 127 at a specific discharge cell, the specific cell is discharged during first through seventh subfields SF1-SF7. That is, 256 grayscales of an image are realized in a PDP by a combination of subfields having different light emitting periods.
According to such a conventional PDP, subfields that do not contribute to grayscales are also driven by the reset period, the address period, and the sustain period, and accordingly, power consumption becomes problematically wasteful. For a detailed example, the grayscale of the level 3 is realized by the first and second subfields SF1 and SF2. That is, for the grayscale of the level 3, the third to eighth subfields SF3-SF8 do not contribute to the grayscale. However, in this case, the reset, address, and sustain periods are also performed in the third to eighth subfields SF3-SF8 that do not contribute to the grayscale, and accordingly unnecessary switching operations are performed, thereby causing wasteful power consumption.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the background of the invention, and therefore, unless explicitly described to the contrary, it should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art that is already known in this country to a person of ordinary skill in the art.

Driving apparatus for plasma display panel and image processing method thereof


A plasma display panel includes a front substrate and a rear substrate opposing one another; display electrodes formed on the front substrate, a dielectric layer formed on the front substrate covering the display electrodes, barrier ribs formed on the rear substrate and including first barrier rib members formed in a direction orthogonal to the display electrodes, and second barrier rib members formed in a direction parallel to the display electrodes, the first barrier rib members intersecting the second barrier rib members to define discharge cells; phosphor layers formed in the discharge cells, and address electrodes realized through conductive wires and coated with a dielectric material, the address electrodes being formed orthogonal to the display electrodes in the discharge cells. The address electrodes may be mounted on the second barrier rib members orthogonal to the display electrodes in the discharge cells.

1. Field of the Invention
The present invention relates to a plasma display panel. More particularly, the present invention relates to a plasma display panel including discharge cells that are defined by barrier rib members formed on a rear substrate of the plasma display panel, in which the barrier rib members intersect and are parallel to display electrodes formed on a front substrate.
2. Description of the Related Art
A plasma display panel (PDP) is a display device that realizes the display of images by the illumination or excitation of phosphors by plasma discharge. Predetermined voltages are applied to electrodes formed on front and rear substrates of the PDP to realize plasma discharge in discharge cells defined by barrier ribs. Ultraviolet rays generated during discharge excite phosphor layers formed in a predetermined pattern to realize the display of visual images.
The PDP is classified into the two different types of the DC PDP and AC PDP, depending on the drive voltage waveform, that is, the discharge type. PDPs can be classified also as an opposing discharge PDP and a surface discharge PDP, depending on the electrode structure. The surface discharge PDP typically includes a front substrate and a rear substrate. Further, address electrodes are formed in a predetermined pattern on the rear substrate, and a dielectric layer is formed on the address electrodes. Barrier ribs are formed on the dielectric layer. The barrier ribs define discharge cells and prevent electrical and optical crosstalk between the cells. Phosphor layers are formed along at least one wall of each of the barrier ribs.
Display electrodes are formed in a predetermined pattern on a surface of the front substrate opposing the rear substrate. The display electrodes are orthogonal to the address electrodes. Further, the display electrodes are formed of a transparent material, and bus electrodes having a width that is less than a width of the display electrodes are formed on the display electrodes to reduce a line resistance of the same. A dielectric layer is formed covering the display electrodes and bus electrodes.
In the PDP structured as in the above, the barrier ribs define the discharge cells and prevent crosstalk between the discharge cells as described above, and also protect the discharge cells from external pressure applied during sealing of the front and rear substrates. If a height of the barrier ribs is increased, a size of the discharge cells is increased. This increases an area of deposition of the phosphor layers, which, in turn, enhances brightness. However, in the conventional stripe configuration of the barrier ribs (where the barrier ribs are aligned with the address electrodes), an increase in the height of the barrier ribs makes the space between the address electrodes and display electrodes greater. Since this increases an address voltage, there is a limit to how high the barrier ribs can be formed.
The applicant disclosed in U.S. Pat. No. 6,495,958 a plasma display panel that includes conductive wire electrodes such that power consumption is reduced during operation. This plasma display panel will be described with reference to FIG. 1.
As illustrated in the drawing, a PDP 100 includes a front substrate 102 and a rear substrate 104. Formed on a surface of the front substrate 102 opposing the rear substrate 104 are display electrodes 106 that include common electrodes 106a and scan electrodes 106b. A dielectric layer 108 is formed on the front substrate 102 covering the display electrodes 106, and a protection layer 110 such as a magnesium oxide layer is formed covering the dielectric layer 108. The common electrodes 106a and the scan electrodes 106b are formed in an alternating manner.
Barrier ribs 112 are formed in a stripe pattern on a surface of the rear substrate 104 opposing the front substrate 102. Discharge cells are formed between the barrier ribs 112. The barrier ribs 112 prevent crosstalk between the cells during discharge. Further, red, green, and blue phosphor layers 114 that are illuminated by discharge gas are formed in the discharge cells. Address electrodes 116 are formed on the phosphor layers 114 in a state orthogonal to the display electrodes 106 of the front substrate 102. The interaction between the address electrodes 116 and the discharge sustain (or display) electrodes 106 induces plasma discharges and has the phosphor illuminate in the neighborhood of the intersection of the address electrodes 116 and the display electrodes 106. The address electrodes 116 are formed as wires made of a conductive metal material such as aluminum, copper, gold, or white gold. The address electrodes 116 are coated with an insulation 118.
In the PDP 100 structured as described above, since the address electrodes 116 are mounted on the phosphor layers 114, the space between the address electrodes 116 and the display electrodes 106 may be reduced over more conventional PDPs in which the address electrodes are covered by a dielectric layer. Accordingly, the amount of power consumed may be reduced during operation of the PDP in proportion to the reduction in the space between the address electrodes 116 and the display electrodes 106. Also, the barrier ribs 112 may be formed to a greater height such that the discharge cells and the phosphor deposition area are increased to enhance brightness and realize more stable discharge.
However, a drawback of the above configuration is that terminal areas of the wire-type address electrodes 116 that protrude to the outside of the PDP are secured only by a sealant used to seal the substrates 102 and 104. This may result in the terminal areas of the address electrodes 116 from becoming unaligned during the sealing process so that a distance between the terminal areas varies from one terminal to the next.


A wavelength-agile laser transmitter apparatus and method are provided. The apparatus comprises a pump laser that is configured to output a pump beam at a first (pump) wavelength and an optical parametric oscillator. The optical parametric oscillator comprises a cavity that contains several optical components including a non-linear optical medium, a first, second and third optical elements, and a narrow linewidth filter. The non-linear optical medium is configured to convert light at the first wavelength to light at a second (signal) wavelength and a third (idler) wavelength that are each longer than the first wavelength. Light at the second and third wavelengths is allowed to partially resonate in the optical parametric oscillator, and the output beam of the apparatus corresponds to light at the third wavelength.

Optical parametric oscillators are well-known, non-linear optical devices capable of producing coherent radiation at a desired frequency via parametric amplification. In a conventional optical parametric oscillator (OPO), a pump source supplies a beam of laser light at a pump wavelength to an optical cavity bounded by end mirrors and containing a non-linear optical medium such as a non-linear optical crystal. As the pump beam propagates through the non-linear crystal within the cavity, photons at the pump wavelength are converted into photon pairs at two longer wavelengths, resulting in two lower-energy beams at these two wavelengths, conventionally called the signal wavelength and the idler wavelength. The sum of the frequencies of the signal and idler beams equals the frequency of the pump beam. The particular wavelengths of the signal and idler beams are determined by a number of factors, including: the pump wavelength, the type and cut of the non-linear crystal, and the design of the optical cavity. In addition, by adjusting the angle of the non-linear crystal, tuning of the signal wavelength and idler wavelength beams can be achieved.
Since typical operating conditions cause only a small fraction of the pump beam to be converted to the signal and idler beams in the initial pass through the non-linear optical crystal, the optical cavity of the OPO is generally designed to oscillate one or both of the parametrically generated beams such that the signal and/or idler beam is amplified in successive passes through the non-linear optical crystal. The OPO is considered a doubly resonant oscillator when both of the generated optical beams are resonated and is considered a singly resonant oscillator when only one of the generated optical beams is resonated. Specifically, the optical cavity can be designed with end mirrors which reflect only one of the signal and idler frequencies (singly resonant) or with end mirrors which reflect both the signal and idler frequencies (doubly resonant).
One application of an OPO is a light source for detection and/or identification of chemical/biological gases. Chemical or biological agents with narrow linewidths require laser linewidths a small fraction of their absorption features for accurate measurements, while other agents with broad features require multiple laser lines and linewidths consistent with atmospheric transmission windows. Thus, an OPO for such applications needs to have a tuning range of multiple (10 or more) wavelengths, be continuously tunable over this range and be capable of operating at a high repetition rate to allow for signal averaging measurements. Moreover, it is desirable to provide and OPO with a high frequency tuning rate for short collection times of data and quick assessment of a sampled region. Finally, the OPO should be relatively light and compact so that it can be deployed on a variety of platforms, including air and land vehicles.

Wavelength-agile laser transmitter using optical parametric oscillator


A release auxiliary device (6) includes a cover part (51) that is provided movably with respect to a receptacle (11) along the insertion/removal direction of a plug (12), and an inclined pressing part (52) that is provided in the cover part (51) and is touchable, from a lower side, to an end portion (41a) of a lever (41). The inclined pressing part (52) presses against the end portion (41a) of the lever (41) and moves the lever by moving the cover part (51) in a direction in which the plug (12) is detached, enabling release of engagement between engaging portions (42, 28).

1. Field of the Invention
The present invention relates to a retention release auxiliary device for an optical connector including a plug to which an optical fiber is coupled and a receptacle into which the plug is inserted.
2. Description of the Related Art
Along with expansion of information networks in recent years, optical fiber communication has become mainstream. Further, it is required to increase the number of optical lines and the density thereof.
A communication device is installed in each node of an optical communication system. A printed circuit board having a function of housing an optical line and controlling the same is mounted on a rack shelf of the communication device. An interface optical connector is mounted on the printed circuit board and an optical fiber is detachably connected to the optical connector. Such optical connectors having various shapes are proposed or standardized (see Japanese unexamined patent publication Nos. 2005-17602 and 11-64682 and Japanese patent No. 3390697). For example, an LC type connector that can be decreased in size and increased in density is normally used in a communication carrier in North America.
Such an optical connector has a latch mechanism for retention. A plug to which an optical fiber is connected is inserted into a receptacle and thereby the latch mechanism operates automatically, ensuring the coupling between the plug and the receptacle. When a lever provided in the plug is operated by fingers to release the latch mechanism, the plug can be detached from the receptacle.
Upon the detachment of the plug, in the case of an environment where a sufficient space is secured, it is easy to operate a small lever with fingers and release the latch mechanism. However, it is not easy in the case where an optical connector is mounted in a small space.
Specifically, usually, a plurality of the printed circuit boards described above are densely mounted on a shelf. In the case where, for example, a plurality of the printed circuit boards are made adjacent to one another and are installed in a slot, a receptacle of an optical connector is attached to a step-like front plate that is fastened to each of the printed circuit boards. In this case, it is necessary to house also an extension area of an optical fiber connected to the optical connector in an area within the shelf. Accordingly, it necessarily follows that the mounting position of the optical connector is a position back from the shelf surface. Under this condition, it is difficult to put fingers in order to attach/detach the plug. In particular, it is hard to operate the lever with fingers to release the latch mechanism.
For this reason, upon the detachment of the plug, a tool is conventionally necessary to release the latch mechanism.

Retention release auxiliary device for optical connector and printed circuit board device


A description is given of colloidal sulphur products, their preparation and their use as additives in lubricating oils. These products result from the reaction on a superbasic detergent additive, optionally modified by reaction with a boron derivative, of a "small size" sulphur carboxylic acid complying with the general formula EQU X--R.sup.1 --Sx--R.sup.3 --Sy--R.sup.2 --COOH. in which R.sup.1 and R.sup.2 each represent a divalent hydrocarbon radical, R.sup.3 represents a single bond or a divalent hydrocarbon radical, X represents a hydrogen atom or a carboxylic group and x and y are in each case a mean value from 1 to 4 when R.sup.3 is a hydrocarbon radical and the sum x plus y is a mean value from 1 to 4 when R.sup.3 represents a single bond. Apart from their detergent properties, these products have high extreme pressure and antiwear properties, as well as an improved thermal stability and a satisfactory corrosivity with respect to copper. They are particularly suitable for use in engine oils, gear oils, hydraulic fluids and metal working oils.

The invention relates to novel sulphur products compatible with lubricating oils. It also relates to the preparation of these products and their use as additives having an extreme pressure and antiwear actions in mineral or synthetic, lubricating oils, e.g. in engine oils, gear oils, hydraulic fluids or metal working oils.
Superbasic detergent additives have been known for a long time. Certain of them and their preparation have e.g. been described in U.S. Pat. Nos. 2,865,956, 3,150,088, 3,537,996, 3,830,739, 3,865,737, 4,148,740, 3,953,519, 3,966,621 and 4,505,830 and French Patent 2,101,813. There are variants of the superbasification reaction using high performance carbonates based on alkoxides and CO.sub.2, prior to the contacting with the alkali metal or alkaline earth salt of the acid compound and are more particularly described in U.S. Pat. Nos. 2,956,018, 3,932,289 and 4,104,180.
It is also known to modify superbasic detergent additives by incorporating boron derivatives, as is e.g. described in U.S. Pat. Nos. 3,929,650, 3,907,691, 4,965,003 and 4,965,004.
Finally, the modification of superbasic detergent additives by certain carboxylic acids, boric acids or phosphoric acids has also been described in U.S. Pat. No. 4,328,111.

Surbased colloidal product containing organic sulfur and their use as detergent additives having an antiwear and extreme-pressure effect in lubricating oils


The invention relates to an ablator composition for providing ablation protection after cure thereof. The. ablator composition includes the components of: (A) 100 parts by weight of a silicone elastomer composition which is curable to a silicone elastomer by addition reaction; (B) 50-200 parts by weight of an amorphous silica having an average diameter from 0.1 to 100 .mu.m; and (C) 1-15 parts by weight of a first fiber having an average length from 0.5 to 6 mm in a longitudinal direction thereof and an average diameter from 1 to 20 .mu.m. The first fiber is at least one of a carbon fiber and a synthetic quartz fiber. An ablating material prepared by curing the ablator composition is superior in heat insulation and substantially low in ablation rate, and thus protects a spacecraft or the like from a high temperature gas, for a long time.

The present invention relates to ablator compositions for protecting the underlying structure of a spacecraft or the like from the aerodynamic heating caused by travel at high speed during reentry through the atmosphere or caused by contact with gas and the like upon combustion of the propellant. An ablating material which is to be applied to the exterior of the underlying structure is prepared by curing the ablator composition.
British Patent Specification 1255132 discloses an ablative coating composition for protecting the surfaces of aerospace vehicles from the eroding effect of hot gases. This composition comprises: (A) 100 parts by weight of a silicone elastomer, (B) 1.0-100 parts by weight of silicon carbide, (C) 1.0-250 parts by weight of silica, and (D) 0.1-15 parts by weight of a high temperature decomposing fiber which melts at a temperature above 1650.degree. C.
Recently, there has been an increasing demand for ablating materials which are further improved in thermal protection and further lowered in ablation rate.


An exhaust gas control system (1) comprised with a continuous regeneration-type DPF (13), an exhaust throttle valve (16) and a DPF control means (30C), wherein the regeneration control is suspended, the multi injection control is performed, and the exhaust throttle valve is closed, when detecting a-stop condition of the vehicle during the regeneration control of the continuous regeneration-type diesel particulate filter device (13) by the regeneration means. Thereby, concerning the regeneration of the continuous regeneration-type DPF device (13), the DPF can be regenerated securely by burning PM efficiently even in a traveling pattern of frequent waiting for the traffic lights to change in urban areas.

The present invention relates to an exhaust gas purification system that purifies particulate matters (hereinafter "PM") from the exhaust gas discharged by diesel and other internal combustion engines using a continuous regeneration-type diesel particulate filter (hereinafter "DPF").
In the same way as for NOx, CO, and also HC etc., restrictions on the volume of PM discharged from internal combustion engines such as diesel engines grow severe every year. Techniques for collecting this PM in a filter known as a DPF and for reducing the quantity thereof by discharging externally have been developed.
DPFs for collecting this PM include a monolithic honeycomb form wall flow type filter made of ceramic, a fiber form type filter made of fiber shape ceramic or metal, and so on. An exhaust gas control system using one of these PDFs are installed on the way of the exhaust passage of an internal combustion engine, similarly to the other exhaust gas control systems, for cleaning exhaust gas generated in the internal combustion engine before discharging the same.
These DPF devices include a continuous regeneration-type DPF device wherein an oxidation catalyst is installed upstream of the DPF, a continuous regeneration-type DPF device wherein the PM combustion temperature is lowered by the effect of a catalyst supported on a filter with catalyst and PM is burned by the exhaust gas, etc.
The continuous regeneration-type DPF device wherein the oxidation catalyst is installed upstream of the DPF uses the fact that the oxidation of PM by NO2 (nitrogen dioxide) is executed at a lower temperature than the temperature at which the oxidation by oxidizing PM with oxygen in the exhaust gas is executed. This DPF device is composed of an oxidation catalyst and a filter. NO (nitrogen monoxide) in the exhaust gas is oxidized to NO2, by an oxidation catalyst supporting platinum or the like on the upstream side. PM collected by the filter on the downstream side is oxidized by this NO2 to CO2 (carbon dioxide). Thereby, PM is removed.
Besides, the continuous regeneration-type DPF device of filter with catalyst is composed of a filter with catalyst such as cerium oxide (CeO2). In this DPF device, PM is oxidized by a reaction (4CeO2+C→2Ce2O3+CO2, 2Ce2O3+O2→4CeO2, etc.) using O2 (oxygen) in the exhaust gas by means of the filter with catalyst, within the low temperature range (on the order of 300° C. to 600° C.). On the other hand, PM is oxidized by O2 (oxygen) in the exhaust gas, within the high temperature range (equal or superior to the order of 600° C.) which is higher than the temperature where PM is burned with O2 in the exhaust gas.
In this continuous regeneration-type DPF device of filter with catalyst, the oxidation catalyst is also installed on the upstream side. The installation of this oxide catalyst raises the exhaust gas temperature, through oxidation reaction of unburned HC and CO in the exhaust gas, and stimulates oxidation and removal of PM. At the same time, this oxidation reaction prevents the emission of unburned HC and CO into the atmosphere.
However, these continuous regeneration-type DPF devices also cause the problem of exhaust pressure rise by the clogging of this filter. In other words, when the exhaust gas temperature is equal or superior to 350° C., PM collected by this DPF is burned continuously and cleaned, and the DPF regenerates itself. However, in case of low exhaust gas temperature and in an operating condition of an internal combustion engine where the emission of NO is low, for example, in case where the low exhaust gas temperature state such as idling of internal combustion engine, low load/low speed operation continues, the oxidation reaction is not stimulated as the exhaust gas temperature is low, the catalyst temperature lowers and the catalyst is not activated and, moreover, NO lacks. Consequently, the aforementioned reaction does not occur and the filter can not be regenerated through oxidation of PM. As a result, PM continues to deposit in the filter and the filter clogging progresses.
As a measure against this filter clogging, it has been conceived to forcibly burn and remove the collected PM by forcibly raising the exhaust gas temperature, when the amount of clogging has exceeded a predetermined amount. As for means for detecting the filter clogging, there are some methods such as a method for detecting by the differential pressure across the filter, and a method for detecting through judgment of the PM accumulation quantity by calculating the quantity of PM collected from the engine operation state from a predetermined map data. Besides, as means for exhaust gas temperature raising, there is a method by injection control of the injection in the cylinder, or a method by fuel control in the direct fuel injection in the exhaust pipe.
The cylinder injection control executes an auxiliary injection after a main injection at a timing delayed from a normal burn so as to continue the burn at a delayed timing, in the case where the exhaust gas temperature is lower than the active temperature of an oxidation catalyst disposed upstream of the filter or supported on the filter. The exhaust gas is heated by executing so-called multi injection (multi-stage injection) to the temperature higher than the active temperature to execute a post injection (posterior injection) and then the fuel in the exhaust gas is burned by the catalytic reaction of the oxidation catalyst. Thereby the filter is regenerated by burning and removing collected PM after raising the exhaust gas temperature higher than a temperature the PM collected in the filter can be burned.
Normally with continuous regeneration-type DPF devices, as disclosed in Japanese patent application Kokai publication No. 2002-276340 and Japanese patent application Kokai publication No. 2003-286887, for example, when the collected quantity of PM reaches a preset limit, the traveling condition is automatically changed to regeneration mode and the collected PM is oxidized and removed by forcibly raising the exhaust gas temperature or increasing the quantity of NOx. And thereby, the filter is regenerated.
In the case where traveling patterns with a high exhaust gas temperature are generally frequent, such as the case in traveling on expressways is the main purpose of the user, an uneven accumulation of PM which does not appear as a differential pressure of the DPF device is developed at the periphery of the filter. Therefore, another method is conceived which forcibly burn the PM during traveling by supplying a traveling distance into a regeneration starting condition.
Nevertheless, in terms of actual traveling conditions, in particular, in such a place like an urban area, traveling and stopping are frequently repeated because of traffic signals and the like. Therefore the repetition makes internal combustion engine load varies between traveling condition and stationary idling condition in a complicated manner and the exhaust gas temperature which is important for the DPF regeneration control varies also in a complicated manner. For this reason, it is possible dependent on traveling patterns that DPF regenerating control will not terminate within the preset time or the exhaust gas temperature is not raised sufficiently. Therefore it arises a problem that the collected PM is not be burned and removed sufficiently.

Control method for an exhaust gas purification system and an exhaust gas purification system


An alteration detection apparatus generates index information based on a document in a storage. The alteration detection apparatus acquires index information that is associated with information identifying a document. The alteration detection apparatus determines whether there is an alteration added to the acquired document based on a result of comparison between the generated index information and the acquired index information. The alteration detection apparatus detects, when there is an alteration, an altered part in the acquired document based on the result of comparison between the generated index information and the acquired index information.

Hash functions have conventionally been used to determine whether there is an alteration in a document subject to verification. For example, in a conventional technique, a hash value of an entire original document and a hash value of an entire document to be verified are compared, and it is determined that there is an alteration in a part of the document subject to verification when the hash values differ from each other. Moreover, in a conventional technique, after determining that there is an alteration in a document, processing to identify an altered part in the altered document is performed (Japanese Laid-open Patent Publication Nos. 2007-052698 and 2013-125445).

Non-transitory computer readable recording medium, alteration detection method, and alteration detection apparatus


Endoprosthesis, such as a stent, includes at least one annular element defined by a first set of strut members interconnected to define apices proximate opposite sides of the annular element. The annular element further includes a foot extension extending between at least one pair of circumferentially-adjacent strut members. The foot extension has first and second foot portions extending circumferentially from corresponding ends of the circumferentially-adjacent strut members, and are contoured to provide at least two areas of flexure. The first and second foot portions are joined at a toe portion of the foot extension, and define a circumferentially-directed apex between the pair of circumferentially-adjacent strut members. Preferably, at least one or more additional annular elements, each defined by interconnected strut members, are provided. The annular elements are generally expandable between a delivery configuration and a deployed configuration. The annular elements are longitudinally aligned and connected at connection locations with connectors, wherein at least one of the connectors is constructed of a bio-absorbable material.

Stents, grafts and a variety of other endoprostheses are well known and used in interventional procedures, such as for treating aneurysms, for lining or repairing vessel walls, for filtering or controlling fluid flow, and for expanding or scaffolding occluded or collapsed vessels. Such endoprostheses can be delivered and used in virtually any accessible body lumen of a human or animal, and can be deployed by any of a variety of recognized means. One recognized indication of endoprostheses, such as stents, is for the treatment of atherosclerotic stenosis in blood vessels. For example, after a patient undergoes a percutaneous transluminal coronary angioplasty or similar interventional procedure, an endoprosthesis, such as a stent, is often deployed at the treatment site to improve the results of the medical procedure and to reduce the likelihood of restenosis. The endoprosthesis is configured to scaffold or support the treated blood vessel; if desired, the endoprosthesis can also be loaded with beneficial agent so as to act as a delivery platform to reduce restenosis or the like.
The endoprosthesis is typically delivered by a catheter delivery system to a desired location or deployment site inside a body lumen of a vessel or other tubular organ. To facilitate such delivery, the endoprosthesis must be capable of having a particularly small cross profile to access deployment sites within small diameter vessels. Additionally, the intended deployment site may be difficult to access by a physician and often involves traversing the delivery system through the tortuous pathway of the anatomy. It therefore is desirable to provide the endoprosthesis with a sufficient degree of longitudinal flexibility during delivery to allow advancement through the anatomy to the deployed site.
Generally endoprosthesis' are constructed of multiple rings that are connected either through a connection section or a connection element, wherein the number of connection sections or elements as well as the thickness of the struts that comprise the rings control the flexibility of the endoprosthesis. Although it is not specifically known how much vessel restenosis can be attributed to stent rigidity, it is know that a reasonably stiff stent may injure the vessel during motion (i.e. pulsatile heart movement). Therefore, it is desirable to produce an endoprosthesis, which has good stiffness properties for deployment within a vessel and wherein the stiffness properties of the endoprosthesis can be changed after deployment within a vessel.
Once deployed, the endoprosthesis should be capable of satisfying a variety of performance characteristics. The endoprosthesis should have sufficient rigidity or outer bias when deployed to perform its intended function, such as opening a lumen or supporting a vessel wall. Similarly, the endoprosthesis should have suitable flexibility along its length when deployed so as not to kink or straighten when deployed in a curved vessel. It also may be desirable to vary the rigidity or flexibility of the endoprosthesis along its length, depending upon the intended use. Additionally, it may be desirable for the endoprosthesis to provide substantially uniform or otherwise controlled coverage, e.g., as determined by the ratio of the outer surface of the endoprosthesis to the total surface of the vessel wall along a given length. For example, increased coverage may be desired for increased scaffolding, whereas decreased coverage may be desired for side access to branch vessels. Control of the cross profile and length of the endoprosthesis upon deployment also is desirable, at least for certain indications.
Numerous designs and constructions of various endoprosthesis embodiments have been developed to address one or more of the performance characteristics summarized above. For example, a variety of stent designs are disclosed in the following patents: U.S. Pat. No. 4,580,568 to Gianturco; U.S. Pat. No. 5,102,417 to Palmaz; U.S. Pat. No. 5,104,404 to Wolff; U.S. Pat. No. 5,133,732 to Wiktor; U.S. Pat. No. 5,292,331 to Boneau; U.S. Pat. No. 5,514,154 to Lau et al.; U.S. Pat. No. 5,569,295 to Lam; U.S. Pat. No. 5,707,386 to Schnepp-Pesch et al.; U.S. Patent 5,733,303 to Israel et al.; U.S. Pat. No. 5,755,771 to Penn et al.; U.S. Pat. No. 5,776,161 to Globerman; U.S. Pat. No. 5,895,406 to Gray et al.; U.S. Pat. No. 6,033,434 to Borghi; U.S. Pat. No. 6,099,561 to Alt; U.S. Pat. No. 6,106,548 to Roubin et al.; U.S. Pat. No. 6,113,627 to Jang; U.S. Pat. No. 6,132,460 to Thompson; and U.S. Pat. No. 6,331,189 to Wolinsky; each of which is incorporated herein by reference.
An additional problem with existing endoprosthesis designs is the difficulty in properly placing the endoprosthesis within a vessel prior to deployment of the endoprosthesis. Current endoprosthesis designs have thinner struts that utilize less radiopaque material and therefore do not appear as well under fluoroscopy. An attempt to address the reduced radiopacity is to include at least one marker band disposed on the delivery device, wherein the marker band may be utilized to indicate an end of the endoprosthesis device or any length there along. Other methods of increasing the radiopacity of an endoprosthesis include the addition of radiopaque markers either disposed upon a surface of the endoprosthesis or within a retaining member associated with endoprosthesis. A shortcoming of present designs is that many are very difficult to manufacture and therefore lead to increased costs. Also, due to size limitations of the radiopaque material used, the markers do not provide sufficient visibility for precise placement.
Another limitation of current endoprosthesis designs is their unsuitability for materials with high elastic limits such as bioabsorbable polymers. The expansion of endoprosthesis devices such as stents generally relies on the plastic deformation of the stent material and typical stent designs do not undergo enough strain during expansion to plastically deform bioabsorbable polymers. This can result in excessive recoil of the stent and sub-optimal apposition of the stent against the vessel wall. Therefore, it is also desirable to provide a stent design that enables expansion of the stent to a greater diameter without plastically deforming the stent material.
Although the various designs for endoprostheses that have been developed to date may address one or more of the desired performance characteristics, there a remains need for a more versatile design for an endoprosthesis that allows improvement of one or more performance characteristics without sacrificing the remaining characteristics.


A compression body is inserted into the contraction joint between two tunnel lining elements, which body deforms in response to a compressive load caused by the tunnel lining elements moving towards each other. The compression body is composed of a material containing voids, and has a compressive strength of at least 1 MPa and a void fraction of between 10% and 90% of its total volume. The compression body may be composed, for example, of steel foam, or of a mixture which contains cement and blown-glass particles or plastic particles.

The exemplary embodiments of the present invention relates to a method and a device for stabilizing a cavity excavated in underground construction. This method and this device are preferably applied in poor rock which exerts pressure but has little strength.
In underground structures (tunnels, galleries, caverns, and the like), a known procedure is to secure the excavated cavity using a lining, i.e., using supporting means such as steel arches, gunned concrete, anchors, and prefabricated concrete elements (tubing). In poor pressure-exerting rock of low strength, the profile of the excavated cavity has a tendency to narrow. This results in forces acting on the lining which generate compressive stresses in the supporting means. The known supporting means under these circumstances are therefore designed so a to be able to give way. As a result of this giving-way action, the pressure of the rock generally subsides.
Publication EP-B-1 034 096 is the most obvious prior art here which shows and describes a tunnel lining which has at least two lining elements acting as supporting segments which are separated by a contraction joint running longitudinally within the tunnel. Upset tubes have been placed into these contraction joints, each of which is located between an outer and inner upset tube and mounted at their faces between two pressure-transfer plates. Pressure is transferred through these pressure plates from the lining segments onto each upset tube. At a given axial load exceeding the buckling resistance of the upset tube, the upset tube buckles in stages and becomes shorter. While overcoming a resistance in the circumferential direction of the tunnel, the lining segments are able to move towards each other and simultaneously exert a resistance of the structure against the rock.
This known tunnel lining has certain practical disadvantages. In the area of the faces of the upset tubes, a local concentration of stress occurs in the lining segments. As a result, other measures must be taken beyond the installation of the pressure transfer plates in order to preclude the lining segments from sustaining damage due to this concentration of stress. This action is disadvantageous in terms of cost. In the case of a lining composed of gunned concrete, the contraction joint must additionally be protected during production of the lining against penetration by the gunned concrete. In addition, problems may arise from a possible tilted position of the upset tubes due to transverse movements by the lining segments relative to each other.

Method and device for stabilizing a cavity excavated in underground construction

Abstract: When a predetermined compressive load is exceeded, the voids within the compression body collapse in a stepwise manner, or are compressed in a stepwise manner.


Certain aspects of the present disclosure provide methods and apparatus for multiuser transmission during a grant to utilize unused portion of a transmit opportunity (TXOP) that is assigned to an initiator device. A responder device may receive, from an initiator device, at least one grant to utilize unused portion of the TXOP. In response to the grant and during the unused portion of the TXOP, The responder device may transmit a first message intended for the to the initiator device, and one or more messages intended for one or more other stations using multi-user transmission schemes. The messages transmitted to stations other than the initiator device may include an indication that the station does not need to respond (e.g., with an acknowledgment) upon receipt of the message.

In order to address the issue of increasing bandwidth requirements that are demanded for wireless communications systems, different schemes are being developed to allow multiple user terminals to communicate with a single access point by sharing the channel resources while achieving high data throughputs. Multiple Input Multiple Output (MIMO) technology represents one such approach that has recently emerged as a popular technique for next generation of communication systems. MIMO technology has been adopted in several emerging wireless communications standards such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard. The IEEE 802.11 denotes a set of Wireless Local Area Network (WLAN) air interface standards developed by the IEEE 802.11 committee for short-range communications (e.g., tens of meters to a few hundred meters).
The IEEE 802.11 (REVmb) standard defines a Reverse Direction Grant (RDG) mechanism, which allows a station to grant time to a responding station to send data frames. The regular media access control (MAC) protocol (without RDG) may only allow transmission of an acknowledgment message after short inter-frame space (SIFS). The RDG protocol extends the regular MAC protocol to allow data transmission in addition to the acknowledgment transmission after SIFS.
As defined in the IEEE 802.11 standard, data transmissions during an RDG are restricted to frames that are addressed to the station that granted the RDG (e.g., the RDG initiator). This 'single user' limitation may preclude a station from sending data frames to multiple stations simultaneously, or sending data frames to the stations that are not the RDG initiator.

Multi-user transmission during reverse direction grant


A transfer device for indexing workpieces through successive stations of a die in a stamping press is provided wherein the carriage and work engaging fingers are driven through separate drives actuated by the press ram. Each drive has an output shaft for operating the carriage and work engaging fingers, respectively. Each drive is compact and saves space by utilizing a plurality of links to drive the output shaft through 180.degree. of rotation so that desired accelertion and decelaration can be achieved. Each drive is a stand-alone mechanism adapted for use with existing transfer devices.

A transfer device comprises a base on which a workpiece carriage is slidably mounted for movement to successive work stations. The carriage in turn supports workpiece gripping fingers. Such transfer devices are disclosed, for example, in U.S. Pat. Nos. 3,165,192; 3,411,636 and 4,032,081. Such transfer devices are operated by the ram of a press through an actuator mounted on the carriage for reciprocation along a path parallel to the path of travel of the carriage on the base. The ram drives the actuator and further drives both the carriage and the workpiece engaging fingers through numerous gears. During travel of the actuator, the workpiece engaging fingers are moved inward or outward to engage or disengage a workpiece, depending upon the direction of travel of the actuator, and thereafter, the carriage is shifted on the base laterally with respect to the finger movement through a stroke corresponding to the distance between successive stations.
Such prior transfer devices incorporate a cam and/or a rack and pinion to drive an output shaft to actuate the carriage and work engaging fingers. With prior cam driven transfer devices, only 90.degree. rotation of the output shaft was possible to drive the carriage and the work engaging fingers. As a result, the work engaging fingers, for example, start moving at a slow acceleration and end movement at the highest velocity resulting in high impact forces between the fingers and the workpieces. This produces wear of parts and subjects the device to shock with the possibility of damage. Rack and pinion drives allow 180.degree. shaft rotation resulting in carriage and finger motion starting at a slow acceleration and decelerating at the end of movement to avoid backlash and high inertial forces. However, in order to achieve the 180.degree. rotation, the rack must be excessively long requiring much space and, for example, interferes with changing of the die.
It is therefore a general object of the invention to provide a drive for each a carriage and for work engaging fingers that achieves optimum acceleration and deceleration through its range of motion to avoid damage caused by backlash and high inertial forces, that is an independent stand-alone assembly adapted for use with existing transfer devices, and that is compact and saves space.


A method of forming an electronic device includes etching a portion of a first gate dielectric layer to reduce a thickness of the gate dielectric layer within that portion. In one embodiment, portions not being etched may be covered by mask. In another embodiment, different portions may be etched during different times to give different thicknesses for the first gate dielectric layer. In a particular embodiment, a second gate dielectric layer may be formed over the first gate dielectric layer after etching the portion. The second gate dielectric layer can have a dielectric constant greater than the dielectric constant of the first gate dielectric layer. Subsequent gate electrode and source/drain region formation can be performed to form a transistor structure.

1. Field of the Disclosure
This invention relates generally to electronic devices, particularly electronic devices having gate dielectric layers that are partially etched.
2. Description of the Related Art
Electronic components in electronic devices continue to decrease in size, while the density of components increases. In particular, the processing requirements for forming such electronic devices is becoming more involved. Electronic devices have transistors and each type of transistor may include different gate dielectric layers. The type of gate dielectric layer may be determined by calculating the necessary capacitance of a region. Varying the thickness of the gate dielectric layer, varying the type of gate dielectric material, or combination thereof is a typical method of controlling the capacitance of a region.
Typically, when forming electronic components, particularly gate structures, a form-mask-etch process sequence is repeated for gate dielectric layers. The effect of the form-mask-etch process is to effectively form different gate dielectric layers of different thicknesses where each gate dielectric layer is separately formed during differential growth or deposition cycles. However, the repetition of the process exposes the substrate surface to chemicals that roughen the surface of the substrate.
The surface roughening of the substrate, which can result from the repetitious form-mask-etch process sequence may cause locations of high electrical field and non-uniform gate dielectric thickness. The effect of which is increased likelihood that the electronic device will have a region of failure and degradation of the overall device. Moreover, processes that require many forming steps are more expensive and increase manufacturing costs of the device. Therefore, the longer and the more involved the process, the more likely the processing will degrade the components quality while increasing the prices to manufacture.


A force sensing resistor includes two substrates. Conductive traces including first, common, and calibration fingers are on the first substrate and define a contact area. A spacer surrounds the contact area and attaches the substrates together such that a cavity separates the substrates in the contact area. A first resistive layer is on the second substrate and arranged within the cavity. In response to a force moving one substrate, the first resistive layer electrically connects the first and common fingers with a resistance dependent upon resistivity of the first resistive layer and the applied force to produce an electrical signal indicative of the applied force. A second resistive layer is arranged within the cavity and electrically connects the calibration and common fingers with a resistance dependent upon resistivity of the second resistive layer to produce an electrical signal indicative of the resistivity of the second resistive layer.

1. Field of the Invention
The present invention generally relates to force sensing resistors and, more particularly, to a force sensing resistor (FSR) having a calibration element and to a method of manufacturing such an FSR.
2. Background Art
Pressure sensitive transducers ("pressure transducers") generate a signal indicative of the amount of pressure applied to a flexible substrate. Pressure transducers may also generate a signal based on the location of pressure applied to the flexible substrate. Pressure transducers provide input for a wide variety of applications such as remote controls, game controllers, mouse pads, tactile sensors, and the like.
A construction for a pressure transducer includes one or more force sensing resistors (FSR). Various FSRs have been disclosed, such as those described in U.S. Pat. Nos. 4,314,227; 4,314,228; and 4,489,302. A typical FSR includes three parts: a (flexible or rigid) base, a spacer, and a flexible resistive substrate. Electrically conductive traces are arranged on the base typically in separated interdigitated sets. These traces may be configured in a single zone or in multiple zones to allow, for example, pointing devices as described in U.S. Pat. Nos. 5,659,334 and 5,828,363. The spacer spaces apart the flexible resistive substrate from the base. The spacer is typically a ring of material placed onto the base around the outer edge of the conductive traces. The spacer is also typically coated with an adhesive to connect the base to the flexible resistive substrate and hold the FSR together.
The flexible resistive substrate may be made of a polymer coated on its inner face with semi-conductive or resistive ink, giving force sensing properties to the FSR. U.S. Pat. Nos. 5,296,837 and 5,302,936 describe such FSR ink. FSR ink has a high humidity coefficient of resistance. When an FSR is used in changing humidity conditions, the high humidity resistance coefficient of the FSR ink limits the usefulness of the FSR to situations where only changes in force may be measured.
In pressure transducer applications, an FSR determines applied force. Such force, for example, may be the force applied by a finger to a button; the force applied to the barrel of a pen; the force applied in each direction of a four-direction pointing device; etc. In each application, the resistance of the FSR is measured and then converted to a force using a known relationship between force and resistance. This known relationship depends on the FSR geometry and on the mechanical characteristics of the actuator that contacts the FSR surface and is typically determined independently for each designed application.
A pressure transducer may include many FSRs arranged in a pattern or an array across the area of the pressure transducer. The location of an object touching the pressure transducer may be determined by which of the FSRs are activated in response to the touch. Typically, pressure transducers are manufactured in mass quantities over time. A problem is that manufacturing tolerances between the FSRs of pressure transducers manufactured over time may be +/−25%. These tolerance variances are caused by day-to-day and batch-to-batch FSR ink inconsistencies and by daily variations in manufacturing equipment setup. Thus, a need exists for an FSR that may be corrected for the effects caused by manufacturing variations and for the effects caused by temperature and humidity variations.

Force sensing resistor with calibration element and method of manufacturing same


An electrical connector includes a female connector (10) and a male connector (20). The female connector (10) includes a female connector body (11) and a vertical wall (12) that define an accommodating space (17), a positioning block (13) disposed in the accommodating space (17), a latch edge (121) and a blocking wall (122) protruded from the vertical wall (12), and a latch space (18) defined by the latch edge (121) and female connector body (11). The male connector (20) having front, rear, and side end surfaces (211, 212, 213) is plugged into the accommodating space (17) and includes a male connector body (21), an extension plate (22), and a hook (23) latched to the latch edge (121), and the rear end surface (212) abuts the blocking wall (122), and the side end surface (213) has a positioning notch (217) for positioning the positioning block (13).

In the field of electronic products, signals are transmitted through a conductive wire or a printed circuit installed on a circuit board. If it is necessary to transmit the signals from the conductive wire to a printed circuit of the circuit board or vice versa, the two are generally electrically coupled to each other through a wire-to-board electrical connector for convenient assembling.
In general, the electrical connector includes a female connector and a male connector, wherein the former has an accommodating space and a pair of latch edges; the latter includes a male connector body, a pair of elastic arms extended from the male connector body and disposed with an interval therebetween, and a hook extended from each elastic arm. When used, the male connector is installed into the accommodating space of the female connector and the hook of each elastic arm is latched to one latch edge, so that the male connector is fixed to the female connector securely.
To detach the male connector from the female connector, each elastic arm is flipped, removing each hook from its latch edge to separate the two connectors successfully. Because each elastic arm is in a slender strip shape, the structural strength is poor, as the elastic wall may be easily broken off from the male connector body when the each elastic arm is flipped. Obviously, the conventional electrical connector requires improvements.
In view of the foregoing problem, the inventor of the present invention, based on years of experience in the related industry, conducted extensive research and experiments to develop an electrical connector in accordance with the present invention to overcome the problem of the prior art.


The present invention relates to a lid for closing a centrifuge rotor, characterized by a form-fitting, rotation-actuated closure mechanism which, pre-positioned on the centrifuge rotor, moves automatically into a closed position by virtue of the intrinsic weight of the lid.

Centrifuges are devices with which containers can be subjected to centrifugal force. In the laboratory, for example, suspensions in test tubes can be treated in this way in order to precipitate the floating solid material at the bottom of the test tube. As a rule, centrifuges have a rotary drive with a vertical drive shaft, on which a rotor can be placed. Normally provided in the rotor are compartments, into which containers which are to be centrifuged can be inserted. The rotors of the centrifuge are often interchangeable, in order to centrifuge vessel contents in one of the rotors while other rotors are only just being loaded with containers, or can be ready for further processing together with containers already centrifuged.
Since, for example, test tubes are pushed into the rotors so as to be open at the top, operational reliability is served, inter alia, by keeping the containers in a liquid-tight chamber during the centrifuging in the rotor. On the other hand, this chamber should be accessible as well as possible for the purpose of simple loading. Since, in particular in the laboratory, a number of actions are often carried out at the same time and the centrifuges nevertheless have to be closed carefully, it is particularly advantageous to be able to use devices having as few actions as possible, having as little actuating movement as possible and, if at all possible, operationally reliably with only one hand. In this regard, known centrifuges need improvement.


The present invention makes it possible to improve the accuracy of wet etching and miniaturize a semiconductor device in the case of specifying an active region of a vertical type power MOSFET formed over an SiC substrate by opening an insulating film over the substrate by the wet etching. After a silicon oxide film having a small film thickness and a polysilicon film having a film thickness larger than the silicon oxide film are formed in sequence over an epitaxial layer, the polysilicon film is opened by a dry etching method, successively the silicon oxide film is opened by a wet etching method, and thereby the upper surface of the epitaxial layer in an active region is exposed.

The present invention relates: to a semiconductor device, and in particular to a technology effectively applicable to a semiconductor device including a silicon carbide substrate, and a manufacturing method thereof.
A semiconductor power device is required to have a low on resistance and a low switching loss in addition to a high withstanding voltage but the performance of a silicon (Si) power device that currently is the mainstream is coming close to its theoretical limits. Silicon carbide (SiC) has a breakdown field strength about one digit larger than Si and hence the resistance of a device can be reduced theoretically by not less than three digits by reducing the thickness of a drift layer to retain withstanding voltage to about one tenth and increasing an impurity concentration by about a hundred times. Further, SiC has a band gap about three times larger than Si and hence can withstand high temperature operation and an SiC semiconductor device is expected to have performance exceeding an Si semiconductor device.
With attention focused on the advantages of SiC, the research and development of a DMOS (Double-Diffused MOSFET) as a power MOSFET (Metal Oxide Semiconductor Field Effect Transistor) of a high withstanding voltage has been advanced.
An example of a manufacturing method of a DMOS is described in Patent Literature 1 (Japanese Unexamined Patent Application Publication No. 2008-227172). It describes that a stepped section that is an insulating film having a film thickness larger than a gate insulating film is formed beside the gate insulating film by a thermal oxidization method by making use of the accelerated oxidation characteristic of an amorphous layer as a substrate.

Manufacturing method of semiconductor device and semiconductor device


Aqueous concentrate herbicidal compositions are provided comprising a herbicidally effective amount of ammonium salt of N-phosphonomethylglycine wherein the molar ratio of ammonia to N-phosphonomethylglycine provides a pH of about 6 to about 7, and a herbicidal efficacy enhancing amount of one or more surfactants. Compositions of the invention are storage-stable over a wide range of temperatures. Also provided is a method of killing or controlling vegetation comprising diluting a composition of the invention in water and applying the diluted composition to foliage of the vegetation.

N-phosphonomethylglycine, otherwise known as glyphosate, is well known in the art as an effective post-emergent foliar applied herbicide. Glyphosate is an organic compound with three acidic groups, and in its acid form is relatively insoluble in water. Glyphosate is, therefore, normally formulated and applied as a water-soluble salt. Although monobasic, dibasic and tribasic salts of glyphosate can be made, it has generally been preferred to formulate and apply glyphosate, in the form of a monobasic salt, for example as a mono-(organic ammonium) salt such as the mono(isopropylamine), often abbreviated to IPA, salt. Roundup.RTM. herbicide containing the IPA salt of glyphosate is sold by Monsanto Company as an aqueous solution concentrate (SC) formulation which is generally diluted in water by the user prior to application to plant foliage. The mono-(inorganic ammonium), i.e., NH.sub.4.sup.+, salt of glyphosate is also commercially available, mainly contained in dry water-soluble granule (SG) formulations such as Rival.RTM. herbicide and Roundup.RTM. Dry herbicide of Monsanto Company, which are dissolved in water by the user prior to application to plant foliage. Other commercial glyphosate products include Touchdown.RTM. herbicide of Zeneca, an aqueous SC formulation containing the mono(trimethylsulfonium), often abbreviated to TMS, salt of glyphosate, and Roundup.RTM. Geoforce herbicide of Monsanto Company, a dry SG formulation containing the monosodium salt of glyphosate.
When the terms "ammonium", "monoammonium" and "diammonium" are used herein to refer to salts of glyphosate, these terms apply strictly to inorganic ammonium, i.e., NH.sub.4.sup.+, unless the context demands otherwise. Glyphosate rates and concentrations given herein, even where the glyphosate is present as a salt or salts, are expressed as acid equivalent (a.e.) unless the context demands otherwise.
Various salts of glyphosate, methods for preparing salts of glyphosate, formulations of glyphosate or its salts and methods of use of glyphosate or its salts for killing and controlling weeds and other plants are disclosed in U.S. Pat. No. 4,507,250 to Bakel, U.S. Pat. No. 4,481,026 to Prisbylla, U.S. Pat. No. 4,405,531 to Franz, U.S. Pat. No. 4,315,765 to Large, U.S. Pat. No. 4,140,513 to Prill, U.S. Pat. No. 3,977,860 to Franz, U.S. Pat. No. 3,853,530 to Franz, and U.S. Pat. No. 3,799,758 to Franz. The aforementioned patents are incorporated herein in their entirety by reference.
Glyphosate salts generally require the presence of a suitable surfactant for best herbicidal performance. The surfactant may be provided in the concentrate formulation, or it may be added by the end user to the diluted spray solution. The choice of surfactant is very important. For example, in an extensive study reported in Weed Science, 1977, volume 25, pages 275-287, Wyrill and Burnside found wide variation among surfactants in their ability to enhance the herbicidal efficacy of glyphosate.
Use of a highly concentrated aqueous formulation of glyphosate in the form of a salt made with the inorganic base ammonia would be advantageous. Ammonia is lower in cost than most other bases, readily available, low in molecular weight, relatively highly soluble in water and a natural nutrient for the growth of plants and other organisms. The use of ammonium salts of glyphosate for preparing aqueous concentrate formulations of glyphosate suitable for killing and controlling weeds and other plants has, however, been limited until the present invention disclosed herein. The limitations reported have included one or more of the following: difficulties arising from chemical and physical properties of the ammonium salts of glyphosate, lack of definition of suitable surfactants for preparing high-loaded liquid concentrates of such salts, reduced weed control, and requirement for complex processes for preparing liquid ammonium glyphosate compositions substantially lower in the amount of glyphosate acid equivalent than the compositions of the present invention.
Preparations of aqueous herbicidal compositions of glyphosate, all or part of which is in the form of its monoammonium and/or diammonium salts, have been disclosed. European Patent No. 0 290 416 discloses aqueous concentrates containing a cationic polyoxyalkylene alkylamine (including alkenylamine) surfactant together with glyphosate, a portion of which is in the form of the monoammonium salt and another portion of which is in the form of a salt wherein the surfactant provides the counterion. The formulations composed partly of monoammonium glyphosate as disclosed in this European Patent have a maximum total concentration of glyphosate in all forms present of 300 grams of acid equivalent per liter (g a.e./l) and are formed by a multi-step process involving separately preparing the monoammonium and surfactant salts of glyphosate in order to be able to combine them in mixture.
In Weed Research, 1996, volume 36, pages 241-247, Nalewaja, DeVilliers and Matysiak disclose the use as herbicides of compositions containing monoammonium and diammonium glyphosate as well as compositions based on the isopropylammonium, sodium and calcium salts of glyphosate. These compositions did not contain any surfactants as prepared. Two nonionic surfactants and one cationic surfactant were separately added, immediately before application to plant foliage, to relatively dilute solutions with indicated maximum glyphosate concentration of less than 10 g a.e./l. The monoammonium and diammonium salt compositions reportedly exhibited less herbicidal activity and glyphosate uptake than the corresponding isopropylammonium salt compositions and required the addition of surfactant separately.
Herbicidal aqueous concentrate formulations of water-soluble salts of glyphosate containing ammonium sulfate have been reported in European Patent 0 274 369. The glyphosate used was reported to be in the form of the isopropylammonium salt; however the presence of ammonium cations together with glyphosate anions resulting from introduction of ammonium sulfate could be considered to provide ammonium glyphosate.
Water-soluble dry solid compositions based on monoammonium glyphosate as agriculturally acceptable herbicidal formulations containing effective surfactants have been developed to overcome some of the aforementioned limitations. As disclosed in European Patent Application No. 0 378 985 and European Patent Application No. 0 582 985, the usefulness of these solid non-aqueous formulations has been limited by one or more of the following: the generally complex, lengthy, and relatively expensive processes for preparation, inconvenient handling properties, and difficulties in agronomic usage. In addition, although many farmers and agricultural spray operators exhibit no strong preference between dry and liquid formulations, a substantial proportion strongly prefer to use liquid, especially aqueous, formulations for a variety of reasons.
It is, therefore, an objective of the present invention to provide a storage-stable, highly concentrated aqueous formulation containing an ammonium salt of glyphosate in a herbicidally effective amount together with a herbicidal efficacy enhancing amount of one or more agriculturally acceptable surfactants.
This objective is rendered particularly difficult by the problems of surfactant compatibility with ammonium glyphosate solutions of high ionic strength. For example, in a direct comparison of mono(isopropylammonium) glyphosate and monoammonium glyphosate, it has been found that, at equal glyphosate a.e. concentration in water, a monoammonium glyphosate solution is significantly more difficult to formulate as a storage-stable concentrate than a mono(isopropylammonium) glyphosate solution. This increased difficulty is manifested in various ways, as outlined below.
The range of surfactants compatible with monoammonium glyphosate at, for example, a glyphosate concentration of 360 g a.e./l and a surfactant concentration of 180 g/l, is much more restricted than the range of surfactants compatible with mono(isopropylammonium) glyphosate at the same glyphosate and surfactant concentrations. As one instance, at the illustrative concentrations given immediately above, the surfactant MON 0818 of Monsanto Company, based on polyoxyethylene (15) tallowamine, shows excellent compatibility with mono(isopropylammonium) glyphosate, but is incompatible with monoammonium glyphosate, this incompatibility resulting in immediate phase separation, or "salting out" of the surfactant from the glyphosate salt solution. PA1 For a given surfactant at a given concentration, the maximum concentration, or "loading", of glyphosate a.e. in a storage-stable aqueous concentrate formulation is, for most surfactants, significantly lower in the case of the monoammonium salt than in the case of the mono(isopropylammonium) salt of glyphosate. PA1 For a given loading of glyphosate a.e., the maximum concentration of most surfactants that can be accommodated in a storage-stable aqueous concentrate formulation is significantly lower when the glyphosate is present as the monoammonium salt than as the mono(isopropylammonium) salt. PA1 Additional compatibilizing agents such as octylamine hydrochloride that are unnecessary in aqueous concentrate formulations of mono(isopropylammonium) glyphosate with a particular surfactant can be required for acceptable storage stability in the case of monoammonium glyphosate. PA1 At given glyphosate a.e. and surfactant concentrations, the maximum temperature that an aqueous concentrate formulation can withstand without phase separation is generally lower with monoammonium glyphosate than with mono(isopropylammonium) glyphosate. An indication of this maximum temperature is obtainable by measuring cloud point by methods known to those of skill in the art. PA1 1. quaternized long chain amines: PA1 2. quaternized polyoxyalkylene long chain amines: PA1 3. quaternized pyridines: PA1 4. quaternized carboxylated imidazolines (closed and open chain): PA1 5. trialkylbetaines: PA1 6. amine oxides:
It is a further objective of the present invention to provide a storage-stable, highly concentrated aqueous formulation containing an ammonium salt of glyphosate and one or more surfactants and having a superior level of herbicidal effectiveness by comparison with current commercial standard glyphosate salt formulations such as Roundup.RTM. herbicide or Touchdown.RTM. herbicide.
The difficulty of meeting this objective is compounded by the fact that herbicidal effectiveness of glyphosate salt solutions is highly dependent upon two factors: selecting a suitable surfactant and providing as high a concentration of that surfactant as possible in the concentrate formulation. Using the monoammonium salt of glyphosate in place, for example, of the mono(isopropylammonium) salt militates against both of these factors.
Even without replacing the salt of glyphosate, it is difficult to enhance the herbicidal effectiveness of the present Roundup.RTM. and Touchdown.RTM. formulations, containing respectively the mono(isopropylammonium) and mono(trimethylsulfonium) salts. Any substantial increase in the concentration of surfactant in these products is achievable only at the expense of reducing glyphosate a.e. loading. Likewise, any substantial increase in glyphosate a.e. loading of these products is achievable only at the expense of surfactant concentration and therefore brings with it at least a risk of reduced herbicidal effectiveness.
Thus the hurdle to be surmounted in developing an aqueous ammonium glyphosate formulation that meets all the criteria of (i) having a high glyphosate a.e. loading, (ii) containing a suitable herbicidal efficacy enhancing surfactant, and (iii) having a high enough concentration of that surfactant to provide herbicidal effectiveness greater than that of commercial standard glyphosate salt formulations, is truly a high one. Nonetheless, the objectives set out above have now been met by the invention described and claimed herein.

High-loaded ammonium glyphosate formulations


In a dental device for the investigation of the optical properties of tooth tissue, in particular for the recognition of caries, plaque, bacterial infection, concretions and tartar, having a generator for generating an excitation radiation, which is to be directed onto a tooth tissue region to be investigated, a radiation detector and a radiation evaluator for the detection and evaluation of a response radiation arising from the irradiated tooth tissue region as response to the irradiation, and an indicator means for the indication of a measurement result determined by the evaluation means on the basis of the detected response radiation, the excitation radiation generator, the radiation detector and at least also the indicator being integrated in a dental handpiece.

1. Field of the Invention
The invention relates to a dental device for the investigation of the optical properties of tooth tissue. In particular the present invention relates to a device for the detection of fluorescent substances on teeth, for example of caries, plaque, bacterial infection, concretions or tartar.
2. Related Technology
In dental diagnostics, optical investigation devices, with the aid of which for example caries, plaque, bacterial infection, concretions or tartar can be recognized, have long been known and known in different variants. It is common to all known devices that a tooth tissue region to be investigated is first irradiated with an excitation radiation, in response to which a response radiation is issued from the tooth. This response radiation may contain both the return reflected radiation of the same wavelength and also a fluorescence radiation. The response radiation is in turn detected and delivered to an evaluation unit which on the basis of the spectrum of the response radiation determines whether one of the above-mentioned substances is present or not. The known optical diagnostic methods and devices differ thereby in the employed wavelength(s) for the excitation radiation and in the evaluation of the detected response radiation. A first possibility consists in investigating whether there has arisen at the tooth a fluorescence radiation as reaction to the excitation radiation. Another possibility consists in, in the case of so-called reflection spectrometry, investigating which wavelengths are reflected in what manner from the tooth surface.
Devices of this kind are described for example in DE 297 04 185 U1, DE 197 09 500 C1 or DE 100 13 210 A1. These known devices have a dental handpiece with an investigation probe, via which the excitation radiation is directed to the tooth to be investigated and the response radiation radiated back from the tooth is detected. The light source for generating the excitation radiation is thereby often arranged directly in the handpiece, whilst in contrast the evaluation of the response radiation is mostly effected in a console, which is connected with a handpiece via connection tube. This console has on the one hand the electronics for the control of the light source for the excitation radiation and also for the evaluation of the response radiation. Beyond this, there are provided at the console indicator means of the form of a display, which depict the measurement results and thereby provides information as to whether the region just investigated manifests one of the above-mentioned fluorescent substances or not. The final diagnosis, i.e. the determination whether the increased fluorescence is caused by caries or not, is then made by the dentist.

Dental device for the investigation of the optical properties of tooth tissue