The invention relates to compounds of general formula I

This invention relates to novel compounds which can inhibit angiogenesis, i.e. which can inhibit the generation or maturation of new blood vessels. It is believed that said compounds may be beneficial in the treatment of a variety of diseases, such as neoplastic diseases and in particular cancer.
It is now widely accepted that blocking angiogenesis around tumours could be a viable way of treating cancer, possibly as an adjuvant treatment. This is also reflected in the large number of development projects and clinical trials with angiogenesis inhibitors with different inhibitory approaches. It is estimated that more than 300 drug candidates are currently in various stages of testing [Matter, DDT, 6, 1005-1024, 2001]. The formation of new blood vessels is a very complex process, which may be targeted in a number of different ways. The candidate drugs, hence, include metalloprotease inhibitors, inhibitors of vascular endothelial growth factor (VEGF) formation, inhibition of VEGF receptors, integrin antagonist, growth factor antibodies, etc.
Of particular interest for the present invention are VEGF receptor inhibitors, most particular VEGFR-2 (KDR) receptor inhibitors. The clinically most advanced VEGF receptor inhibitor is semaxanib from Sugen, which was recently discontinued in Phase III studies. Analogues of semaxanib, however, continue to be in development. Another VEGF receptor inhibitor in clinical trial is PTK-787 from Novartis which has recently entered Phase III studies. Bilodeau has reviewed such inhibitors in clinical trials in Expert Opin. Investig. Drugs., 11, 737-745, 2002.
WO 01/29009 and WO 01/58899 describe pyridine derivatives as inhibitors of the VEGF receptor tyrosine kinase and the VEGF-dependent cell proliferation.
WO 02/090346 describes phthalazine derivatives as inhibitors of the VEGF receptor tyrosine kinase with angiogenesis inhibiting activity.
WO 04/056806 teaches 2-(1-H-indazol-6-ylamino)-benzamide compounds as protein kinases inhibitors which may be useful for the treatment of ophthalmic diseases.
PCT publications WO 00/27819, WO 00/27820, WO 01/55114, WO 01/81311, WO 01/85671, WO 01/85691, WO 01/85715, WO 02/055501, WO 02/066470, WO 02/090349, WO 02/090352, WO 03/000678, WO 02/068406, WO 03/040101, and WO 03/040102 all teach anthranilic acid amide derivatives which include compounds of general structure A, their preparation and their use as VEGF receptor tyrosine kinase inhibitors for the treatment of diseases associated with VEGF-dependent cell proliferation.

The use of anthranilic acid amide derivatives for other therapeutic purposes have previously been disclosed in, e.g. U.S. Pat. No. 3,409,688 (analgesic, anti-inflammatory, antiulcer), and in EP 564,356 (angiotensin II antagonist).
PCT publications WO 02/06213 and WO 99/01426 teach substituted phenylamino benzhydroxamic acid derivatives which include compounds of general structure B as MEK inhibitors, pharmaceutical compositions and methods of use thereof.

U.S. Pat. No. 5,155,110 teaches hydroxamic acid derivatives having cyclooxygenase and 5-lipoxygenase inhibiting properties and pharmaceutical compositions for treating conditions advantageously affected by the inhibition. The reference fails to describe tyrosine kinase inhibitory activity of the hydroxamic acid ester derivatives disclosed.

Hydroxamic acid esters and pharmaceutical use thereof

Abstract: wherein D, E, F, G, W, Y, R1, A, R9, X, B, R8 are as defined herein, and pharmaceutically acceptable salts, hydrates, or solvates thereof, for use—alone or in combination with one or more other pharmaceutically active compounds—in therapy, for treating diseases associated with deregulated angiogenesis, such as cancer.


Method and apparatus of splicing a paper web, in which a paper web from a new reel is spliced to a paper web from an emptying reel and a position of glue or two sided tape in the surface of the new paper reel is marked. The method includes receiving a command for splicing, determining the splicing time instant, accelerating a rotation of the new paper reel, detecting the glue or tape, controlling, based on the detected glue or tape, the rotation of the new paper reel in such a manner that the rotation speed of the new paper reel and the position of the glue or tape are as required at the splicing time instant, and splicing the paper web at the splicing time instant.

In some machinery relating to paper manufacturing, paper webs of the machine reels can be joined so that the post processing can be applied in a continuous manner. For example, in coating machines that are not part of the paper machine, the machine reels can be unwound through the coating machine one-by-one such that the paper can be spliced at full speed. The splicing of paper web refers to a process in which once a machine reel has become empty, the paper from a new machine reel can be attached to the paper from the previous reel so that the post-processing machine can run in continuous manner.
In splicing, the paper from the new machine reel can be glued or taped to the paper of the previous reel before the material in the previous reel ends. The remaining material length is estimated via rate of change in roll diameter, paper thickness calculation and speed. The new reel of material can be prepared by placing glue or two-sided tape to the surface of the material along the width of the reel. The new reel is accelerated such that the surface speed of the new reel corresponds with the speed of the web from the previous reel. The new reel-roll acceleration is initiated well in advance to be fully ready and stable before the splice takes place and material from previous reel runs out. The foreseen time of splice may have some inaccuracy, which is why sufficient time margin is added at a starting point.
When the new reel has reached the desired speed and position, a separate splicing roll or brush pushes the web from the previous reel to the surface of the new reel. The applied glue or tape attaches the webs together after which the web from the previous reel is cut. This way the post-processing machinery, such as an off-machine coating machine, can run continuously without interruptions.
In a splicing process the amount of material left in the emptied reel can be minimized so that as little as possible material is wasted. The tail of the material in the emptied reel can be problematic because after the web has been cut, the material from the previous reel can keep on unwinding for a few more seconds before stopping. This hanging tail can lead to unwanted breaks in the web when it, or parts of it, ends in the route of the new web. Mechanical brakes can be used for braking the emptied reel to stop it as fast as possible for avoiding the problems relating to the hanging tail.
WO 00/40491 discloses a method in which the amount of material left in the emptied reel can be minimized. The minimization can be carried out by gluing the paper layers together near the bottom of the reel, thus preventing the paper to unwind past this point. Making use of this requires the splicing and cutting to happen very close but still before the glued bottom layers appear, so that the cut and hanging tail can be stopped by the glue before any excess unwinding. The position of the bottom glue is identified to the system by a premark in the edge of the web, for example, a fixed distance before. The premark is done together with the bottom glue, in roll preparation area, before the coater.
In known splicing methods, such as in U.S. Pat. No. 4,077,580, when the diameter of the old reel reaches a certain value, the new reel is accelerated to the required splicing speed. The acceleration is carried out with constant parameters. The start of the acceleration takes place in good time before the actual splicing so that the new reel may rotate for minutes.
When the conditions for splicing are met, i.e., the diameter of the old reel reaches another limit, the angular position of the new reel is unknown or at least not predicted. This means that the splicing instant must be delayed until the new reel reaches a known position and then the required position for starting of the splicing. It may take up to one rotation of the new reel for waiting of the known and the required position, and the splicing can be started only after one more rotation of the new reel. Thus, when the conditions for splicing are met, the new reel is still be rotated one to two rotations, which can equal approximately 10 to 22 meters of paper from the old reel.
One of the disadvantages associated with the above methods is that the methods still leave unnecessary tail on the emptied reel. The tail can be up to the length corresponding the whole circumference of the new reel plus distance from emptied reel paper tangent to the cutting device plus the safety margin.
Further, the new reel is rotated somewhat longer than required, which may affect the adherence of the splice because the glue or tape on the surface of the rotating roll dries quickly.

Method and apparatus for accelerating a roll to a target


A package container forming flap apparatus capable of forming a tubular packaging material in a rectangular shape in cross section with reliability and accuracy. The package container forming flap apparatus lateral seal bars for laterally sealing a tubular packaging material, a pair of opposing fixed plates which are disposed respectively over each lateral seal bar in parallel with a seal surface thereof, forming arms for turning about axes which are parallel to a longitudinal direction of the tubular packaging material, and movable plates which are secured to the forming arms and together with the fixed plates to shape the tubular packaging material in a rectangular shape in cross section.

1.Field of the Invention
The present invention relates to a package container forming flap apparatus in a filling and packaging apparatus for manufacturing package containers each having a rectangular shape in cross section and filled with a fluid content such as juice, etc. and a method of forming the package container using the same.
2. Prior Art
There is known a conventional filling and packaging apparatus comprising a rewinder for supporting a packaging material web in a rolled state, a winding apparatus for winding the web in order from the rewinder, a tube-forming apparatus for forming the wound web in a tubular shape after sterilizing it, a liquid supply pipe for filling a fluid content in the tubular shaped packaging material web, and a container-forming apparatus for laterally sealing the tubular web filled with the fluid content and cutting a sealed part of the tubular web to continuously form pillow-like containers each having a rectangular shape in cross section while downwardly supplying the tubular web by the length corresponding to one container, and a container shaping apparatus for bending each end part of the pillow-like containers to shape each pillow-like container in a parallelepiped container to be finally obtained (as disclosed in JP-A 58-193206 and JP-A 61-93010).
As a package container forming flap of a container forming apparatus in such a filling and packaging apparatus, it is known that a tubular body is formed in a rectangular shape by the movement of two pistons from two directions crossing at right angles with opposing plates after the tubular body is supplied between the opposing plates (U.K. Patent Number 1,012,867), or a tubular packaging material is formed in a box-shape from the bottom to the top thereof using longitudinal forming flap members 4 which turn longitudinally about axes 3 disposed in a direction parallel with a direction crossing at right angles with a longitudinal direction of the tubular packaging material 2 over the lateral seal bars 1 as shown in FIG. 1 when forming a liquid filling and packaging container by filling a content in a tubular packaging material web, laterally sealing and cutting this web after the plate-shaped packaging material web is formed in the tubular packaging material web (JP-A 58-193206) or a protrusion and a recess are provided on opposing surfaces of the forming flap members for forming the tube in a rectangular shape (JP-A 5-32208).
However, there are following drawbacks in these forming flaps.
In the forming flap as disclosed in U.K. Patent Number 1,012,867, the structure of the forming flap is made large and complex since the tubular body is formed in a rectangular shape by the plates and the pistons.
In the forming flap disclosed in JP-A 58-193206, since the forming flap members are turned in the longitudinal direction when the tubular shape is changed to a box-shape by the forming flap members, a soft packaging material such as paper is nipped between contact surfaces of the opposing forming flap members in the longitudinal direction, so that a fold or wrinkle 5 is produced at the side surfaces of the tubular packaging material 2 as shown in FIG. 2, which causes a problem that an external appearance is deteriorated, the tubular packaging material 2 does not have an intended size of the container, and proper inner capacity of the container is not obtained, thereby impairing a product value.
Further, since the forming flap members are turned approach to each other in a longitudinal direction thereof to form the tubular packaging material from a circular shape in cross section to a rectangular shape in cross section, the container has an inverted trapezoidal shape in longitudinal cross section because of the adjustment of the inner capacity of the container, which causes a problem of inconvenience of packaging or carriage of the container. Still further, the surface of the packaging material web is liable to be damaged because the inner surfaces of the forming flap members and the web slide when forming the tubular packaging material web.
In the forming flap as disclosed in JP-A 5-32208, the protrusion and the recess are defined on the contacting surfaces of the opposing forming flap members to improve the drawback of JP-A 58-193206 that the longitudinal forming flap members nip the packaging material web in the longitudinal direction thereof, whereby the nipping of the packaging material web can be prevented to some extent but it is not completely prevented. Further, the problem of inconvenience of the shape of the container that the container has the inverted trapezoidal shape in longitudinal cross section has not been solved so far.

Package container forming apparatus flap


Systems, methods and computer program products, implementing techniques for automatic data acquisition and the real-time display of automatically acquired data. A system implementing the techniques includes one or more automatic data acquisition devices that emit data; and a data integration system that receives data from the automatic data acquisition devices and processes the data. The data integration system includes a display system for displaying the data to a user. The display system is operable to generate a graphical display and to update the graphical display automatically and only when new data from the automatic data acquisition devices is available. The display system is operable to update only affected parts of the graphical display but not necessarily the entire display.

The present disclosure relates to data processing by digital computer, and more particularly to automatic data acquisition and the display of automatically acquired RFID (Radio Frequency Identification) data and sensor data.
Systems exist for integrating data acquisition devices such as RFID tag readers and sensor devices with enterprise software applications that make use of the data acquired by the data acquisition devices. In this specification, such systems will be referred to as data integration systems.
Data integration systems typically provide an application programming interface through which the enterprise applications can access the data collected by the data integration system. However, conventional data integration systems typically do not provide a user interface through which a human user can view the automatically acquired RFID and sensor data.


The present invention facilitates a control of a temperature of white color and color tones of respective colors of a color liquid crystal display device. To achieve such an aim, a display device of the present invention includes a display panel which arranges a plurality of color filters which differ in color for each pixel, and at least the color filter of one color is formed of a plurality of filter layers stacked on a transparent substrate.

1. Field of the Invention
The present invention relates to a display device and a manufacturing method thereof, and more particularly to a technique which is effectively applicable to a color liquid crystal display device.
2. Description of the Related Arts
As one of display devices, there exists a color liquid crystal display device which includes a liquid crystal display panel capable of performing a color display. The color liquid crystal display device is a display device which is capable of performing a high-definition color display and, recently, has been popularly used as a liquid crystal display panel for a liquid crystal television receiver set or a PC (Personal Computer), a display for a PDA (Personal Digital Assistant), a mobile phone or the like.
The liquid crystal display panel which is used in the color liquid crystal display device (hereinafter referred to as color liquid crystal display panel) is, for example, a display panel which is constituted by sealing a liquid crystal material between a first substrate (a TFT substrate) which arranges TFT (Thin Film Transistor) elements and pixel electrodes in an array and a second substrate (a color filter substrate) which arranges color filters of R (red), G (green) and B (blue) at positions corresponding to the pixel electrodes. Here, in the color liquid crystal display panel, a display pixel of one dot is constituted of a set which is formed of a R pixel having the red color filter, a G pixel having the green color filter, and a B pixel having the blue color filter.
In manufacturing the color filter substrate, for example, first of all, a black matrix which separates the R pixels, the G pixels and the B pixels on a transparent substrate formed of a glass substrate or the like is formed. Then, the red color filter for the R pixel, the green color filter for the G pixel and the blue color filter for the B pixel are sequentially formed on the transparent substrate.
In forming the color filters, a method which performs patterning of a resist in which pigment is dispersed using a photolithography method is most popularly adopted. In this method, for example, first of all, a negative resist in which pigment is dispersed is applied to a whole surface of the transparent substrate by coating, a solvent is removed by evaporation from the resist by heating so as to dry the resist. Next, the negative resist is exposed through a photo mask which blocks light except for predetermined pixel regions. After exposure, the resist in the pixel region is cured by light and is made insoluble against a developer. Accordingly, in developing the resist using alkaline solution, only regions except for the pixel regions are developed and removed whereby a pixel pattern of the color filter is obtained. Such steps are repeatedly performed with respect to the red, green and blue color filters.
Further, there also exists a method which uses a dry film resist in place of such a coating-type resist (for example, see Japanese Patent Laid-open Hei5-173320 (document 1)). In this method, a film-like negative resist in which pigment is dispersed is adhered to a transparent substrate by thermo-compression bonding and, thereafter, the above-mentioned exposure and development are performed thus forming a pixel pattern of a color filter. This method can simplify the step for forming the resist on the transparent substrate compared to the method which coats the resist. Further, by preliminarily forming an oxygen interrupting layer on the resist of the transfer film, a curing action is accelerated thus increasing the sensitivity of the resist. On the other hand, however, the method has demerits or drawbacks such as a high material cost, and no flexibility in a delicate control of color tones by changing coated film thicknesses.
Further, recently, aiming at the reduction of a material cost and a manufacturing cost, a method which forms a pattern by supplying pigment-dispersed ink to only pixel portions such as high accuracy printing (for example, described in Japanese Laid-open No. 294930/2003 (patent document 2) and ink jet printing (for example, described in Japanese Laid-open No. 221319/2000 (patent document 3).
Corresponding to a usage or an application to which the color liquid crystal display device is applied, a demand for, for example, a temperature of white color obtained by synthesizing lights which pass through the R pixel, the G pixel and the B pixel, the color reproducibility of respective colors and the like differs. Accordingly, in manufacturing the color filter substrate, it is necessary to control color tones of filter materials used for color filters of respective pixels by taking, for example, the color temperature of white color and the color reproducibility of respective colors into consideration.
As one of methods of controlling the temperature of white color and color reproducibility of respective colors, there exists a method which changes a film thickness of the pigment-dispersed resist. However, when the film thickness is largely changed, there arises a drawback such as irregularities in coating thickness and hence, only the color-tone change at a level of fine adjustment is possible. Accordingly, when the film thickness adjustment cannot cope with the required temperature of white color or the color reproducibility of respective colors, there arises a drawback that it is necessary to prepare a new pigment-dispersed resist in which the color tone is adjusted by changing a kind of pigment and a blending ratio of pigment. Further, each time the color filter substrate which differs in the temperature of white color and the color reproducibility of respective colors is manufactured, a changeover operation of the pigment-dispersed resist becomes necessary and hence, there arises a drawback that the production efficiency is lowered. Here, these drawbacks are drawbacks which are also shared in common by pigment-dispersed ink used in the above-mentioned high-definition printing and ink jet printing.
Further, as a method for controlling the temperature of white color and the color reproducibility of respective colors, for example, there has been also known a method which changes the numerical apertures of the respective pixels consisting of the R pixel, the G pixel and the B pixel, for example. However, in adopting this method, for example, it is necessary to change a pattern of an exposure mask corresponding to numerical apertures of the respective pixels or it is necessary to change sizes of the pixel electrodes on the TFT substrate. Accordingly, there has been a drawback that it is necessary to individually prepare the above-mentioned CF substrate and the TFT substrate corresponding to the required temperature of white color and color reproducibility of the respective colors.
It is an object of the present invention to provide a technique which facilitates a control of a temperature of white color and color tones of respective colors in a color liquid crystal display device, for example.
It is another object of the present invention to provide a technique which can easily form color filters of arbitrary color tones using a same filter material.
The above-mentioned object, other objects and novel features of the present invention will become apparent from the description of this specification and attached drawings.

Display device and manufacturing method thereof


A device for damping the movement of a movably supported structural part, in particular of a flap or the like in an automotive vehicle, where a tooth segment is located on the structural part, the tooth segment co-operating with a pinion which is associated with a rotary damping element and stationarily located relative to the structural part, whereby the rotary damping element is attached to a pivotally supported arm, in that the rotary damping element or the arm, respectively, has an extension, a guide portion being provided at the free end of the arm which co-operates with a guide path on the structural part such that the distance between the pinion and the tooth segment remains approximately constant.

It is known for movable or pivotally supported structural parts in automotive vehicles, such as, for example, glove compartment covers, lids for ash-trays, holding grips or the like to exert a bias thereon by means of a spring and/or gravity. In connection with a cover for a glove compartment such a part is biased by a spring towards the open position. When actuated in the closed position it is only necessary to release the locking mechanism so that the cover opens automatically. In the case of a holding grip such a part is automatically biased towards its rest position. It is also known to dampen the movement of such structural parts by suitable damping means in order to moderate the effect of the spring means. Thus, undesired acoustic effects and wear are avoided. In many cases so-called rotary dampers are used. Rotary dampers usually include a rotor rotatably supported in a housing. A pinion is mounted upon the shaft of the rotor which meshes with a tooth segment. If a flap, cover or lid or the like is moved, the rotor is contemporarily rotated. A gap is formed between the rotor and the housing filled with a viscous medium adapted to perform a rotary dampening operation. A typical rotary damper is disclosed in the German patent publication DE 33 20 069.
Conventional rotary dampers have a damping effect in both rotational directions. In many cases this is not desired. If for example a cover for a glove compartment is biased to its opened position by a spring or by gravity, this force has to be overcome if the cover is closed manually. Also the damping effect of the rotary damper has to be overcome which may require a relatively high force.
Therefore, it has also become known to provide the rotary dampers with a free wheel mechanism. Such rotary dampers have a damping effect only in one rotational direction, whereas in the opposite direction the resistance against rotation is relatively small. Such a rotary damper is known from the German patent publication DE 37 22 114. Between the rotor and a shaft a ratchet clutch is connected such that a locking takes place only in one rotational direction. The coupling parts are biased by a spring towards each other. From the Austrian patent publication OE 224 496 it is known to provide a rotary damper for the hinge of a door, with the damper including a clutch spring which coacts with the walls of bores of the parts to be coupled. A disengagement of the coupling parts is achieved when the spring is wound up.
Rotary dampers which include a pinion and a tooth segment may develop noise. Above all, if the space between the pinion and segment changes, noise may not be avoided. Conventional arrangements of the kind described, however, cannot avoid tolerances.

Device for damping the movement of a movably supported structural part, in particular of a flap in an automotive vehicle of the like


A method for accounting for negative bias temperature instability in a rise delay of a circuit design, the method comprising the steps of create a cell and net model library with original rise numbers, construct the circuit design from the cell and net models, for each cell and net in the circuit design, calculate an original rise delay, apply a negative bias temperature instability model to determine a parameter shift, determine a new rise number from the parameter shift, and calculate a new rise delay by original rise delay* (original rise number)/(new rise number).

When a PMOS device is subjected to different operational conditions, a shift in certain operating parameters, such as threshold voltage, can often be observed. For example, when a PMOS device is operated at a given temperature and gate bias for a given time, there tends to be a shift, or degradation, in the threshold voltage of the device. This effect is generally referred to as negative bias temperature instability. This phenomenon tends to have a large effect on analog circuit elements, such as source coupled MOSFET pairs. However, the effect tends to be transient, and the threshold voltage returns to about its original value when the charged states de-trap after the gate stress is removed.
When designing an integrated circuit, issues such as negative bias temperature instability should be accounted for, or the integrated circuit may not function properly. Certain integrated circuits, such as mixed signal cells, analog circuits, and I/O circuits may not function at all. In addition, the effects of negative bias temperature instability tend to be different for alternating current devices than they are for direct current devices.
Various experiments have been performed to measure negative bias temperature instability effects on various transistor parameters, such as voltage threshold and saturation current, at different physical conditions, such as alternating current, direct current, gate voltage, temperature, frequency, duty cycle, and stress time. Different models have been developed based upon the experimental data so produced. These models all tend to correlate a given parameter shift as a function of duty cycle, frequency, time, and temperature.
A common practice in the industry is to build the model for such parameter shifts into a larger circuit modeling routine, such as a PMOS HSPICE model library, and characterize the cell library with the negative bias temperature instability model. One drawback of this approach is that the worst case parameter is built into the model library in order to cover all possible operating conditions. Because the model is frequency and temperature dependent, this approach tends to over margin the design in most embodiments. Another drawback of this approach is that the negative bias temperature instability worst case corner—high voltage and high temperature—does not match the worst case delay corner—low voltage and high temperature. Thus, this corner-centric model library may not represent the true worst case negative bias temperature instability effect. Multiple corner libraries tend to be prohibited due to the large HSPICE simulation time required.
What is needed, therefore, is a system for including negative bias temperature instability models in integrated circuit models that overcomes problems such as those described above, at least in part.

Negative bias temperature instability modeling


A heat exchanger for use in exchanging heat between corrosive or electrolc fluids has wetted components which are comprised of corrosion and erosion resistant materials. The use of corrosion and erosion resistant tube sheets, shell, and tubes permits the heat exchanger to operate at high flow rates to produce turbulent flow through the inlet tube sheet and tubes, thereby optimizing transfer efficiency between a corrosive fluid in the tubes and the regenerated fluid pumped through the shell.. In order to eliminate problems of temperature gradient and vibrations at the area where the tubes are joined to the inlet tube sheet, the shell is comprised of an inner and outer shell section to form annular flow diverting chambers therebetween. The inner shell section of each chamber is apertured so that flow is diffused over the entire surface, thereby avoiding direct impingement of fluid over the tubes.

The present invention relates generally to a regenerative heat exchange system for transferring heat from one fluid to another and pertains more particularly to a shell and tube system which is capable of transferring heat between electrolytic or corrosive fluids. The present invention is particularly suited for marine use such as in coastal installations, on drilling platforms, or aboard marine vessels where sea water is used as the cooling fluid.
In conventional marine duty heat exchangers, where sea water is used as the cooling fluid, the tube bundles are constructed of copper-alloy tubes and are mounted within a tubular steel shell. Steel inlet and outlet tube sheets are coupled to the inlet and outlet ends, respectively, of the shell by appropriate flanges and are correspondingly apertured to receive and support the ends of the tubes. Cooling seawater passes through the inlet tube sheet and into the tubes, whereupon heat is transferred thereto by recirculating a heated fluid through the shell.
The steel, copper alloy and other materials presently used in the construction of marine duty heat exchangers are heavy and subject to both corrosion and erosion. Copper alloy tubes are particularly subject to erosion at high fluid velocities. Prior art heat exchangers rely on the maintenance of non-turbulent flow conditions to prevent erosion of the tubes and other wetted components. For example, if sea water is pumped through a 3/4" diameter tube at a flow velocity through the center of the tube of approximately 8 ft/sec, laminar flow conditions can be established. Under laminar flow conditions, a thin layer of fluid at the tube walls is maintained at zero velocity, thereby eliminating the problem of erosion.
Unfortunately, however, the same thin layer of fluid at the tube walls which prevents erosion also results in a higher convective resistance and thus impedes heat transfer between the fluids. Since the turbulent flow regimes obtained at fluid velocities of 25 ft/sec or more are required for optimum heat transfer between the fluids, the reduction in erosion achieved by reducing fluid velocity to maintain laminar flow in the tubes comes at the direct expense of heat transfer efficiency.
Another disadvantage of reducing the flow rate of fluid within the pipes is a heightened risk of fouling the sea water side of the inlet tube sheet with biological material. Formations of scale deposits on the inlet side of the heat exchanger are also a problem associated with low flow rates.
It is therefore an object of the present invention to provide an erosion and corrosion resistant heat exchanger apparatus which also provides high transfer efficiency.
It is another object of the present invention to provide a heat exchanger apparatus which can be readily retrofitted into existing installations.
It is yet another object of the present invention to provide a heat exchanger which is resistant to fouling and the formation of scale deposits.
It is still another object of the present invention to provide a method of repairing the tubes within a heat exchanger constructed in accordance with the present invention.
It is also an object of the present invention to eliminate problems caused by tube vibrations at the tube sheets and by temperature gradients within the shell.

Corrosion resistant shell and tube heat exchanger and a method of repairing the same

The United States of America as represented by the Secretary of the Navy


A system and method of DFT-S-OFDM modulation is provided that uses a set of frequency domain patterns. For a given transmitter, for a set of DFT-S-OFDM symbols, the frequency domain pattern changes according to a time domain hopping pattern. Advantageously, the time domain hopping patterns are defined to allow only a certain amount of overlap, for example for only one DFT-S-OFDM symbol, between any two time domain hopping patterns. This functions to reduce the effect of a collision, when two transmitters use the same frequency pattern, they will do so only for part of the overall transmission. Optionally, frequency domain spectral spreading is used in the transmitter. This can further reduce the PAPR. In the receiver, successive interference cancellation may be employed to reduce the effect of colliding transmissions.

Non-Orthogonal Multiple Access (NoMA) is mainly intended for massive machine-type communications (mMTC). For mMTC devices, low peak-to-average power ratio (PAPR) waveform is desirable. However, many proposals for NOMA assume an orthogonal frequency division multiplexed (OFDM) waveform, which has high PAPR.
Efforts at collision mitigation for such OFDM-based NoMA schemes have focused on frequency domain resource mapping pattern and spreading sequence design.
Compared to some other NoMA schemes, interleave-grid multiple access (IGMA) has two advantages:
It consumes minimum spatial dimension, and hence has the best minimum mean square error (MMSE) interference rejection combining (IRC) performance;
It is applied to an OFDM waveform. While one transmitter's transmission can collide with another's, colliding with some transmissions may have minor impact due to, for example, low correlation in the spatial domain, while colliding with other transmissions may have a more severe impact. For transmissions that experience a severe impact, soft log likelihood ratios (LLRs) derived from severely impacted quadrature amplitude modulation (QAM) symbols can be significantly lower than those from other QAM symbols, but these lower LLRs can still contribute to decoding by a low code rate FEC code.
However, extending IGMA to create a low PAPR waveform is not straight forward.
It is well-known that single-carrier based waveforms have low PAPR compared to OFDM. One example of a single-carrier waveform is discrete Fourier transform-spread-OFDM (DFT-S-OFDM).
However, the effect of frequency domain partial collision upon DFT-S-OFDM is distortion. In other words, any distortion caused by a partial collision will remain in the demodulated signal, and its effect cannot be mitigated by soft LLR weighting. Another way to state this is that per-collision based soft information is lost in DFT-S-OFDM, because unlike in OFDM, a collision in DFT-S-OFDM is not per-QAM symbol based.

Modulation scheme in a wireless communication system


A dynamic interspinous process device for implantation with respect to a first vertebra and an adjacent second vertebra is provided. The dynamic interspinous process device may include a first attachment side and a second attachment side. Each of the first attachment side and second attachment side may include a central portion, a first wing extending from the central portion, a second wing extending from the central portion, and one or more slots extending from an interior side of the respective attachment side to an exterior side of the respective attachment side. The one or more slots of the respective attachment side may be configured to allow the first wing and the second wing to move relative to one another in a direction of a longitudinal axis of the dynamic interspinous process device.

Various types of implantable devices for spinal surgery, which generally may be referred to as "spinal devices" or "spinal implants," are commonly used to treat a variety of spinal conditions by stabilizing adjacent vertebrae in an effort to restore and maintain normal spacing and orientation of the treated vertebrae. Certain spinal devices, which may be referred to as "rigid devices" or "fusion devices," are configured to stabilize adjacent vertebrae in a substantially rigid or fixed manner to promote fusion (i.e., bone growth) between the adjacent vertebrae. Rigid devices may effectively fix the relative spacing and orientation of adjacent vertebrae until fusion is achieved, which may be facilitated by bone graft or bone growth promoting substances. Upon fusion, rigid devices may provide a load sharing function in combination with the bone formed between the adjacent vertebrae. Other spinal devices, which may be referred to as "dynamic devices" or "motion devices," are configured to stabilize adjacent vertebrae in a dynamic manner that allows a degree of relative movement between the adjacent vertebrae. As a result, dynamic devices may allow adjacent vertebrae to move relative to one another, such as in flexion, extension, lateral bending, and/or axial rotation of the spine, thereby inhibiting fusion between the adjacent vertebrae. Dynamic devices may provide a load sharing function in combination with the native spinal disc between the adjacent vertebrae or may carry substantially all loads applied to the respective vertebrae in instances where the spinal disc is removed. Rigid devices or dynamic devices may be used in the treatment of various degenerative diseases of the spine, including spondylolisthesis, degenerative disc disease, spinal osteoarthritis, degenerative scoliosis, and recurrent disc herniation, as well traumatic spinal injury. Example spinal devices include pedicle screws, facet screws, rods, plates, interbody cages, artificial discs, and other types of spacers, some of which may be used as stand-alone devices or may be used in combination with one another. Such spinal devices may be configured for rigid or dynamic stabilization, and the selection between rigid or dynamic treatment may depend on the type and/or severity of the spinal disease or traumatic injury to be addressed.
An interspinous process device, which also may be referred to as an "ISP device," is one type of spinal device that may be used for treatment of various spinal conditions. Generally described, an interspinous process device may include a portion that is positioned within an interspinous process space between a pair of adjacent vertebrae (i.e., the space between the spinous process of a first vertebra and the spinous process of an adjacent second vertebra) and one or more additional portions that interface with the spinous processes, the laminae, and/or other portions of the respective vertebrae. In certain instances, interspinous process devices may be used primarily to distract the spinous processes and restrict extension of the treated segment of the spine. Such devices may be referred to as "interspinous distraction devices" and generally may not be fixed to the vertebrae upon implantation thereof. In other instances, interspinous process devices may be used for fixation purposes to facilitate fusion of the treated segment of the spine, although such devices also may function to distract the spinous processes of the respective vertebrae. Such devices may be referred to as "interspinous fixation devices" and generally may be fixed to the respective vertebrae by one or more engagement features.
Certain interspinous process devices, which may be referred to as "rigid devices" or "fusion devices," are configured to stabilize adjacent vertebrae in a substantially rigid or fixed manner to promote fusion (i.e., bone growth) between the adjacent vertebrae. In this manner, such interspinous process devices may prevent or substantially inhibit relative motion of the adjacent vertebrae. Such rigid interspinous process devices generally may include one or more engagement features for fixedly attaching the device to the spinous processes, the laminae, and/or other portions of the respective vertebrae. Other interspinous process devices, which may be referred to as "dynamic devices" or "motion devices," are configured to stabilize adjacent vertebrae in a dynamic manner that allows a degree of movement between the adjacent vertebrae. Accordingly, such interspinous process devices may allow the adjacent vertebrae to move relative to one another, for example, in flexion and extension of the spine, thereby inhibiting fusion of the treated segment of the spine. Such dynamic interspinous process devices may or may not include engagement features for fixedly attaching the device to the spinous processes, the laminae, and/or other portions of the respective vertebrae.
Although existing interspinous process devices may be suitable for use in various applications, such devices may suffer from one or more potential drawbacks. For example, in some applications, certain rigid interspinous process devices may provide desired stabilization of the treated vertebrae but the lack of relative motion between the vertebrae may result in undesirable loads being carried by the rigid devices and may increase the incidence of failure of such devices over time. Additionally, the fixation provided by certain rigid interspinous process devices and subsequent fusion of the treated segment of the spine may cause increased stresses on the adjacent untreated segments and adjacent segment degeneration. With respect to dynamic interspinous process devices that allow for relative movement between the treated vertebrae, certain dynamic devices may not provide the type of controlled motion as may be desired in some applications. For example, the degree of movement allowed by such devices may be greater than or less than desired in some applications. Additionally, the relative movement between the treated vertebrae may not be adequately constrained in the desired anatomical direction(s). Certain dynamic interspinous process devices also may present issues of engagement between the device and the respective vertebrae becoming compromised over time due to the relative movement of the vertebrae. Moreover, certain dynamic interspinous process devices may have complicated designs including numerous components, which may increase the incidence of device failure and/or may result in the implantation and intraoperative assembly of the device being cumbersome and time consuming Finally, certain dynamic interspinous process devices may lack a means for adjusting the degree of relative movement allowed by the device and/or preventing relative movement, as may be desired. For example, it may be desirable to provide a greater degree or a lesser degree of relative movement in different treatment applications. Further, in certain instances, it may be desirable to change a treatment approach to allow a degree of relative movement or to prevent relative movement, during either an initial surgery or a follow-up surgery.
A need therefore exists for improved interspinous process devices and methods that address one or more of the above-described potential drawbacks of existing technology and allow for the use of interspinous process devices in a broader range of treatment options.

Convertible dynamic interspinous process devices and methods for spinal surgery


The present invention relates to a technique for preparing an anhydrosugar alcohol using hydrogenated sugar as a raw material and, more specifically, to a technique for preparing a high-purity anhydrosugar alcohol (in particular, isosorbide, isomannide, isoidide, and the like) having a purity of 98% or higher and containing less than 0.1% of sorbitol and a sorbitan isomer, which are impurities, in a high total distillation yield of 94% or higher (more preferably, 95% or higher) by adding an acid to hydrogenated sugar (for example, hexitol) to convert same to an anhydrosugar alcohol, and then distilling the converted liquid over two or more stages by sequentially using a combination of an external condenser type wiped film evaporator and an internal condenser type short path evaporator.

Hydrogenated sugar (also referred to as "sugar alcohol") means a compound obtained by adding hydrogen to the reductive end group in sugar, and generally has a chemical formula of HOCH2(CHOH)nCH2OH wherein n is an integer of 2 to 5. According to the carbon number, hydrogenated sugar is classified into tetritol, pentitol, hexitol and heptitol (4, 5, 6 and 7 carbons, respectively). Among them, hexitol having 6 carbons includes sorbitol, mannitol, iditol, galactitol, etc. and in particular, sorbitol and mannitol are very useful materials.
Anhydrosugar alcohol has a diol form with two hydroxyl groups in the molecule, and can be produced by using hexitol derived from starch (for example, Korean Patent No. 10-1079518 and Korean Laid-open Patent Publication No. 10-2012-0066904). Because anhydrosugar alcohol is an environmentally friendly material derived from recyclable natural resources, it has received much interest for a long time and researches on its production continue to proceed. Among such anhydrosugar alcohols, isosorbide produced from sorbitol has the widest industrial applicability at present.
Anhydrosugar alcohol can be used in various fields including treatment of heart and blood vessel diseases, medicaments such as patch adhesive, mouthwash, etc., solvents for compositions in the cosmetics industry, emulsifiers in the food industry, etc. In addition, it can increase the glass transition temperature of polymer materials like polyester, PET, polycarbonate, polyurethane, epoxy resin, etc., and improve the strength of such materials. Furthermore, because anhydrosugar alcohol is an environmentally friendly material derived from natural resources, it is very useful in the plastics industry such as bioplastics and the like. It is also known that anhydrosugar alcohol can be used as an adhesive, environmentally friendly plasticizer, biodegradable polymer, and environmentally friendly solvent for water-soluble lacquer.
As such, anhydrosugar alcohol is receiving much interest because of its wide applicability, and the level of practical industrial application thereof is increasing. However, the conventional methods of producing anhydrosugar alcohol have limitations of high cost for the catalyst used in the dehydration reaction, low conversion rate, and low yields of distillation and purification, etc.
In order to produce anhydrosugar alcohol economically, it is essential to employ a technology of distilling anhydrosugar alcohol from the resulting liquid of conversion reaction within a short time with high yield and high purity.
As a distillation technology of distilling the conversion liquid after dehydration reaction, batch distillation or simple distillation—wherein anhydrosugar alcohol is simply distilled under reduced pressure directly after the conversion reaction in the reactor—is known.
By batch distillation or simple distillation, however, commercial-scale economical production is difficult since the distillation time is long. In addition, if the resulting liquid of a conversion reaction is distilled at a low temperature (e.g., 170° C. or lower), the distillation time increases, and if distilled at a relatively high temperature (e.g., 170° C. or higher), the distillation time decreases but the anhydrosugar alcohol is thermally decomposed at 170° C. or higher, and byproducts such as formic acid, furfural, etc. are generated, by which the purity of the product and the pH of the distillate are lowered. That is, as compared with the wiped-film evaporation explained below, since batch distillation or simple distillation requires relatively longer retention time of distillate and higher distillation temperature, thermal decomposition of alcohol is induced, generating the problem of lowering purity and yield of the distillate. To prevent such a thermal decomposition, use of an additive is required.
In order to overcome the deficiencies of batch distillation or simple distillation in distilling anhydrosugar alcohol from the resulting liquid of a conversion reaction, U.S. Pat. No. 7,439,352 suggested a technology of distilling anhydrosugar alcohol by wiped-film evaporation using an external condenser. In the wiped-film evaporation technology disclosed in this US patent, the condenser is operated outside of the distillator. In this type, however, the maximum vacuum circumstance that can be formed in the distillator technically is 1 mmHg; under such a vacuum degree the distillation temperature should be 170° C. or higher in order to conduct the distillation effectively. However, as stated earlier the anhydrosugar alcohol such as isosorbide is thermally decomposed at a distillation temperature of 170° C. or higher, and thereby the distillation yield and distillation purity are lowered. Accordingly, in the above US patent, the purity of the single-step distillation product is 97.1% or the like and the distillation yield is 80% or the like. However, such levels of purity and yield are still not suitable for a commercial-scale mass-production process.
In the above US patent, the isosorbide purity is increased to 99.9% through distillation of two (2) stages. However, the overall distillation yield is low (first stage/second stage yield 77.5%). To resolve the problem of such a low overall distillation yield, the above US patent employs a separate process for crystallizing the residue of the two-stage distillation and recovering isosorbide therefrom. However, in the overall process flow as such, the isosorbide is produced by two separate processes consequentially, which makes the uniform quality control much more difficult than a single-process production.
Therefore, a technology of producing anhydrosugar alcohol, which can provide high purity (e.g., 98% or higher) and a content of sorbitol and sorbitan isomer as impurities of less than 0.1% with a high overall distillation yield (e.g., 94% or higher, more preferably, 95% or higher), is required.

Method for preparing high-purity anhydrosugar alcohol using sequential combination of thin film distillation and short path distillation


An Oldham ring of a scroll type compressor having a swivel scroll of aluminum alloy. The Oldham ring is of cast aluminum alloy and has a pair of projections (a) serving to engage with a pair of guide grooves formed in a surface of the swivel scroll adjacent to a crankshaft. Sliding surfaces of the projections which are to be brought into contact with inner surfaces of the guide grooves are each covered with a metal sheet made of a metal which is different from aluminum and aluminum alloys. It is recommended that the metal sheet has the following thickness (t): t=0.5-2.5 mm, T/20.ltoreq.t.ltoreq.T/4 (where, T represents the widthwise dimension of the projection in the circumferential direction of the Oldham ring). The metal sheet is united with the Oldham ring by insert casting.

The present invention relates to an Oldham ring which is one of parts constituting a scroll type compressor, and more particularly, to an Oldham ring which is the part serving to prevent a swivel scroll from revolving on its own axis.
In typical scroll type compressors, the swivel scroll is driven by a crank shaft so as to be caused to move in reciprocating motion within a plane parallel to a circular base plate of the swivel scroll. The circular base plate is formed in the bottom surface thereof with a pair of rectilinear guide grooves. An Oldham ring is disposed so as to be adjacent to and parallel with the circular base plate. The Oldham ring has a pair of first projections formed on one surface thereof adjacent to the circular base plate, the first projections being brought into engagement with the guide grooves. The Oldham ring also has a pair of second projections formed on the other surface thereof opposite to the surface on which the first projections are formed, the second projections being brought into engagement with a housing of the compressor so as to prevent the revolution of the Oldham ring. The swivel scroll is driven to reciprocate in the rectilinear direction along the pair of first projections while being restrained from moving in the direction of revolution of itself due to the engagement relationship between the guide grooves and the first projections.
In the conventional scroll type compressor, it has been general to employ a swivel scroll and an Oldham ring made of an iron system material. However, in order to reduce noise and friction loss caused due to high- o speed revolution, it has been hoped eagerly to reduce the weight of the swivel scroll and the Oldham ring of the scroll type compressor. Accordingly, reduction of weight has been realized by making the swivel scroll of aluminum as disclosed in JP-A-62-248887. Further, it has been proposed, for reduction of weight, to make both the swivel scroll and the Oldham ring of aluminum alloy. Namely, as disclosed in JP-A-2-283882, not only the swivel scroll and the Oldham ring has been made of aluminum alloy so as to reduce the weight, but also, as means for avoiding seizure, scuffing and abnormal wearing caused by the sliding movement between aluminum alloy members, an intermediate layer of iron-system material has been disposed in the engaging portion between the swivel scroll and the Oldham ring by thermal spraying the melt of the iron-system material thereto so as to ensure the high-speed revolution.
The method of treating the surface of the engagement portion between the swivel scroll and the Oldham ring as disclosed in JP-A-2-283882 encounters with the problems such as deterioration of the precision of parts caused as a result of treatment, additional cost resulting from the surface treatment, durability of the coating film and the like.


A scan converting method of converting image data from a raster sequence scan to a block sequence scan to divide the image data into blocks each having predetermined vertical width and lateral width and converting the image data from the block sequence scan to the raster sequence scan. One block buffer having a size in which a vertical width is set to the vertical width of the block and a lateral width is set to the horizontal width of the raster is used. Raster data by the raster sequence scan is written into the block buffer. The block data by the block sequence scan is read out. The block data is written and the raster data is read out. Upon conversion from the raster sequence scan to the block sequence scan, the block buffer is read out by the block sequence scan, the raster data is written into empty addresses which are caused by the reading, and the read address by the next block sequence scan is obtained by a predetermined arithmetic operation on the basis of the order of writing. Upon conversion from the block sequence scan to the raster sequence scan, the block buffer is read out by the raster sequence scan, the block data is written into empty addresses which are caused by the reading, and the read address by the next raster sequence scan is obtained by a predetermined arithmetic operation on the basis of the order of writing.

1. Field of the Invention
The invention relates to scan converting methods and apparatus for performing a scan conversion between a raster sequence scan and a block sequence scan which are executed at the time of various image processes, such as image compressing and expanding process, and the like in a television, a scanner, a printer, and the like.
2. Related Background Art
Hitherto, in case of performing a JPEG system image compressing process or the like such as to image process image data every block, it is necessary to convert an order of scanning from an ordinary raster scan sequence of an image as shown in FIG. 1A to a block scan sequence as shown in FIG. 1B. In case of expanding the image, contrarily, it is necessary to reversely convert the scanning order from the block sequence to the raster sequence. For this purpose, as shown in FIG. 1C, two block buffers are provided and are switched. Namely, when converting from the raster sequence to the block sequence, one block buffer is written in accordance with the raster sequence and the other block buffer is read out in accordance with the block sequence. When reversely converting from the block sequence to the raster sequence, one block buffer is written in accordance with the block sequence and the other block buffer is read out in accordance with the raster sequence.
FIG. 2 is a block diagram showing a conventional scan converting apparatus.
In FIG. 2, a raster counter 101 generates an ordinary address for a raster sequence (hereinafter, referred to as a raster address). A block count conversion unit 102 converts the raster address into an address for a block sequence (hereinafter, referred to as a block address). The above two addresses are switched by a multiplexer 103 in accordance with the conversion or reverse conversion and are supplied to two block buffers 104 and 105, respectively. Input/output data is transmitted and received through input/output buffers 106 and 107.
Namely, when converting from the raster sequence to the block sequence, the I/O buffer 106 inputs raster data from the outside such as a camera or the like and is divided into blocks by using the block buffers 104 and 105, and the block data is outputted from the I/O buffer 107 to an image compressing unit or the like. Upon reverse conversion, the expanded block data is inputted to the I/O buffer 107 and is converted to the data of the raster sequence by using the block buffers 104 and 105 and is outputted as raster data from the I/O buffer 106 to a monitor or the like.
FIG. 3 shows a construction of the block count conversion unit 102. In this instance, FIG. 3 shows a case of pixels in which a size of one block comprises 8 pixels (in the vertical direction).times.8 pixels (in the lateral direction).
In FIG. 3, raster addresses which are advanced one by one to ordinary addresses A.sub.0 to A.sub.n from the raster counter 101 are received, address lines of A.sub.3 to A.sub.6 are replaced to upper addresses and are converted to addresses such that middle addresses are set to A.sub.6 to A.sub.r and lower addresses are set to A.sub.0 to A.sub.2, and those addresses are outputted as block addresses B.sub.0 to B.sub.n from an output buffer 109.
Namely, after the addresses of A.sub.0 to A.sub.6 were counted up to "8" in the horizontal direction, the addresses are again counted to "8" with respect to the next line. By repetitively executing the above operations with respect to eight lines, block addresses of one block are obtained. By continuing those operations for 1H, block addresses of one block buffer are derived.
As block addresses in the reverse conversion, the block addresses obtained by converting the upper addresses, middle addresses, and lower addresses of A.sub.0 to A.sub.n into A.sub.3 to A.sub.n-3, A.sub.n-2, to A.sub.r, and A.sub.0 to A.sub.2 are used.
Therefore, the addresses of lower three bits of A.sub.0 to A.sub.2 (corresponding to eight pixels) don't always need to be converted. In the above case, it is necessary to set a condition such that the addresses of a horizontal width (1H) of the block buffer are the power of "2".
In the conventional apparatus mentioned above, however, two sets of block buffers 104 and 105 are necessary, so that a circuit scale is large in proportion to the number of horizontal pixels of a picture plane. Particularly, as compared with the number of pixels of an image to monitor, since the number of horizontal pixels of an image which is handled by a scanner, printer, or the like of a high resolution is extraordinarily large, a scale of the block buffer is very large. When the block buffers are accessed, circuits for producing two kinds of addresses of the raster sequence and block sequence are necessary. There is a problem such that in order to switch each of the block buffers to the raster sequence and the block sequence, a circuit such as a multiplexer or the like to switch two kinds of addresses, a switching circuit such as input/output buffers 106 and 107 or the like to alternately supply the data to the two block buffers or to alternately extract the data from the two block buffers, and the like are necessary, so that in addition to those circuits, a whole circuit scale is extremely large.

Scan converting method and apparatus for raster to block and block to raster using a shared block buffer and two input/output buffers, one being raster, the other scan


An impact tool comprising a motor, a hammer 8 that is rotated and axially moved by a drive force of the motor, an anvil 3 that repeats engagement/disengagement from the hammer 8 accompanying rotation and axial movements of the hammer 8, and a tip tool 4 mounted to the anvil 3, the anvil 3 comprising a first split piece 3A, which includes pawls 3c (first concave-convex part) on an opposite side to the hammer and repeats engagement/disengagement from the hammer 8, a second split piece 3B, which includes pawls 3f (second concave-convex part) engageable with the pawls (first concave-convex part) 3c of the first split piece 3A in a direction of rotation, and to which the tip tool 4 is mounted, and a rubber damper (elastic body) 13 interposed between the first and second split pieces 3A, 3B to prevent direct contact between the pawls (first concave-convex part) 3c and the pawls (second concave-convex part) 3f in the direction of rotation and in an axial direction.

An impact tool being a configuration of a power tool generates a rotary impact force with a motor as a drive source to rotate a tip tool to intermittently give an impact force thereto to perform a work such as thread fastening, etc., and is presently used widely since the impact tool has a feature in that reaction is small, a clamping capacity is high, and so forth. Since such impact tool includes a rotary impact mechanism to generate a rotary impact force, however, noise while working is large to cause a problem.
FIG. 12 shows a longitudinal cross section of a general impact tool used conventionally.
The conventional impact tool shown in FIG. 12 comprises a cell pack 1 as an electric source, and a motor 2 as a drive source, and drives a rotary impact mechanism part to give rotation and impact to an anvil 3, thereby intermittently transmitting a rotary impact force to a tip tool 4 to perform a work such as screwing, etc.
In the rotary impact mechanism part built in a hammer casing 5, rotation of an output shaft (a motor shaft) of the motor 2 is reduced in speed through a planetary gear mechanism 6 to be transmitted to a spindle 7, so that the spindle 7 is rotationally driven at a predetermined speed. Here, the spindle 7 and a hammer 8 are connected to each other by a cam mechanism, the cam mechanism comprising a V-shaped spindle cam groove 7a formed on an outer peripheral surface of the spindle 7, a V-shaped hammer cam groove 8a formed on an inner peripheral surface of the hammer 8, and balls 9 that engage with the cam grooves 7a, 8a. Also, the hammer 8 is constantly biased toward a tip end (rightward in FIG. 12) by a spring 10, and positioned with a clearance from an end surface of the anvil 3 by means of engagement of the balls 9 and the cam grooves 7a, 8a when being stationary. Projections, respectively, are formed symmetrically in two locations on opposite rotary flat surfaces of the hammer 8 and the anvil 3. In addition, a screw 11, the tip tool 4, and the anvil 3 are constrained relative to one another in a direction of rotation. Also, in FIG. 12, the reference numeral 14 denotes a bearing metal that bears the anvil 3 rotatably.
As described above, when the spindle 7 is rotationally driven, rotation thereof is transmitted to the hammer 8 through the cam mechanism, and the projection on the hammer 8 engages with the projection on the anvil 3 to rotate the anvil 3 before the hammer 8 makes a half revolution, but when relative rotations are generated between the hammer 8 and the spindle 7 by reaction forces of the engagement, the hammer 8 begins to retreat toward the motor 2 while compressing the spring 10 along a spindle cam groove 7a. When backward movement of the hammer 8 causes the projection on the hammer 8 to get over the projection on the anvil 3 to release engagement of the both, the hammer 8 is quickly accelerated in a direction of rotation and forward owing to elastic energy accumulated in the spring 10 and the action of the cam mechanism in addition to torque of the spindle 7 to be moved forward by the bias of the spring 10, and the projection thereon engages again with the projection on the anvil 3 to begin to rotate together. At this time, since a large rotary impact force is applied to the anvil 3, the rotary impact force is transmitted to the screw 11 through the tip tool 4 mounted to the anvil 3.
Thereafter, the same actions are repeated, the rotary impact force is intermittently and repeatedly transmitted to the screw 11, and the screw 11 is screwed into a timber 12 being a clamped object.
By the way, since the hammer 8 makes longitudinal movements simultaneously with rotary movements in a work, in which such impact tool is used, these movements serve as a source of vibration to axially vibrate the timber 12, being a clamped object, through the anvil 3, the tip tool 4, and the screw 11 to generate a large noise.
Here, it is found that a noise energy from an object being clamped accounts for a large ratio in noise while working with the use of an impact tool, it is required that a vibration force transmitted to an object being clamped be restricted to a small extent in order to achieve reduction in noise, and various measures have been examined (see, for example, JP-A-7-237152 and JP-A-2002-254335).


The present invention discloses a universal replaceable back radar, wherein a head sleeve and a vehicle-reversing module thereof are separately designed and coated, an ultrasonic head is coupled to the connecting block of the vehicle-reversing module, an angle-adjust pad is also clamped to the connecting block of the vehicle-reversing module, and a big and a small hook platelets each with different heights are separately installed at both sides of one face of the angle-adjust pad and press against the internal face of a downward-tilt or an upward-tilt bumper. The universal replaceable back radar of the present invention can simplify the assemblage thereof and save the coating step thereof and its man-hour.

As the technology and science continuously progress and the standard of living continuously rises, the automobile has been the primary transportation equipment in daily living and brings great convenience to people, and almost every family has at least one automobile now. However, owing to fast-increasing quantity of the automobiles, the streets are crowded with the automobiles; thus, in addition to that driving the automobile always has a crisis of collision, street parking also challenges the driver's skill because of the obstacles around the parking place or other automobiles before or behind the parking bay. Furthermore, some driver, whose driving skill is not sophisticated enough, cannot accurately estimate the distance between the automobile and the obstacles around the parking bay by visual observation, so that a scratch or collision will occur often, which puts a great strain on the driver, and besides the damage of the driver's own automobile, the driver has to reimburse the damage to another's automobile if the collision incurs a damage to another's automobile.
Thus, there is a manufacturer developing a device of back radar, wherein an infrared detector, or another sensor, is installed on the rear bumper or another portion of the automobile and a receiver is installed inside the driving compartment. When reversing the automobile, the detector A installed in the rear of the automobile, as shown in FIG. 1 and FIG. 2, can measure the distance between the automobile and the obstacles behind the automobile. When the distance is equal to or short than the preset value, the receiver inside the driving compartment will display and alarm to remind the driver to keep on reversing or to drive forward. Such a device can help the driver of a big vehicle or the driver lacking sophisticated skill to some extent; however it has the following drawbacks:
Firstly, the inner face the cover flange B1 of the head sleeve B of the conventional detector A is vertical, and the head sleeve B can only apply to a planar bumper and cannot apply to an upward-tilt or downward-tilt bumper; thus, the conventional detector cannot be assembled to various automobiles, and its utilization is limited.
Secondly, in the conventional detector A, the head sleeve B and the ultrasonic head C1 of the vehicle-reversing module C are coated separately before the ultrasonic head C1 is assembled to the device body; however, the appearance of the top portion of the ultrasonic head C1 will be muddled because of the previous coating, and the detecting face's paint of the ultrasonic head C1 cannot be concealed when the ultrasonic head C1 is further assembled into the head sleeve B; thus, additional coating is needed, and additional man-hour is spent thereon.
Thirdly, the head sleeve B and the vehicle-reversing module C are coated separately before assemblage; however, the paint on the surface of the ultrasonic head C1 is apt to be scratched when the ultrasonic head C1 is assembled into the head sleeve B, which needs additional coating step and lowers the efficiency of assemblage; furthermore, the workshop cannot rapidly assemble the ultrasonic head with the device body and the head sleeve B via preparing multiple ultrasonic heads C1 to meet the demand of the consumer; thus, the assemblage thereof is slow and time-consuming.


A memory cell transistor connects its drain with a corresponding subbit line. In a program operation, a selected subbit line is connected to a program main bit line. In a read operation, a selected subbit line is connected with the base of a bipolar transistor, so that a channel current of a selected memory cell transistor flows as a base current. The bipolar transistor amplifies this base current, and controls a current flowing through a read main bit line.

1. Field of the Invention
The present invention relates to a nonvolatile semiconductor memory device, and more specifically, it relates to a nonvolatile semiconductor memory device for writing and erasing data in and from memory cells and reading data from the memory cells with a low power supply voltage.
2. Description of the Background Art
A flash memory, which is a kind of nonvolatile semiconductor memory device, can be fabricated at a lower cost than a dynamic random access memory (DRAM), and is recently expected as a memory device for the future generation.
FIG. 59 is a circuit diagram showing the structure of a memory cell array 5000 of a conventional NOR flash memory. A plurality of word lines WL and a plurality of bit lines BL are arranged on the memory cell array 5000. FIG. 59 representatively shows word lines WL1, WL2, WL3, . . . and bit lines BL1, BL2 and BL3, . . . Memory cells QC are provided on the respective intersections between the word lines WL and the bit lines BL. The memory cells MC are formed by floating gate MOS transistors.
The structure of a memory cell transistor forming each memory cell QC is now described.
FIG. 60 is a model sectional view for illustrating the memory cell transistor of the conventional nonvolatile semiconductor memory device. As shown in FIG. 60, the memory cell transistor has an N-type source region 2 and an N-type drain region 3 formed on a major surface of a P-type semiconductor substrate 1, a floating gate electrode 5 formed above a channel region which is held between the source region 2 and the drain region 3 through a tunnel oxide film 4, and a control gate electrode 7 formed above the floating gate electrode 5 through an insulating film 6. The source region 2 and the drain region 3 of each memory cell transistor is formed by ion implantation through masks of side wall insulating films 9 formed on side walls of the floating gate electrode 5 and the control gate electrode 7.
Referring to FIGS. 59 and 60, a source line SL is connected to the source region 2 of each memory cell QC. A bit line BL is connected to the drain region 3. A word line WL is connected to the control gate electrode 7.
The source-to-drain conductivity (channel conductance) varies with a potential applied to the control gate electrode 7. The potential of the control electrode 7, which is so increased that a current starts to flow between the source and the drain, is called a threshold voltage Vth. The threshold voltage Vth is increased as electrons are stored in the floating gate electrode 5.
The memory cell transistor stores information by changing the charged state of the floating gate electrode 5. The floating gate electrode 5, which is electrically isolated from the exterior by the insulating films 9, is in a structure for storing information in a nonvolatile manner.
Read, write and erase operations of the NOR flash memory are now briefly described.
In the write operation, electrons are injected into the floating gate 5 by channel hot electron injection. Thus, the threshold voltage Vth of the memory cell transistor changes from a low level to a high level.
In the erase operation, the electrons are extracted from the floating gate electrode 5 by an F-N (Fowler-Nordheim's) tunnel phenomenon at a gate edge of the source or the drain. Thus, the threshold voltage Vth changes from a high level to a low level.
In the read operation, a voltage of about 1 V is applied to a selected bit line BL and an external power supply voltage VCC is supplied to a selected word line WL, for reading information depending on whether or not a current flows between the source and the drain of the memory cell transistor positioned on the intersection between the selected word line WL and the selected bit line BL.
FIGS. 61 and 62 illustrate threshold voltage distributions of the NOR flash memory. As shown in FIG. 61, such a state that the threshold voltage Vth is higher than the external power supply voltage VCC (5 V) is referred to as a write state, and such a state that the threshold voltage Vth is lower than the external power supply voltage VCC (5 V) is referred to as an erase state in the NOR flash memory.
The NOR flash memory writes information bitwise, and simultaneously erases information from all bits or bits included in every prescribed block. Therefore, the threshold voltage distribution in the erase state is wider than that in the write state.
As shown in FIG. 62, employment of the present external power supply voltage VCC of 3.3 V results in the so-called overerased cells having threshold voltages Vth of not more than 1.5 V.
FIG. 63 is a circuit diagram for illustrating the problem of overerased cells in the flash memory. It is assumed that data is read from a memory cell QC1 which is connected to a bit line BL and memory cells QC2, QC3, QC4, . . . connected to the same bit line BL are overerased. A voltage of about 1 V is applied to the bit line BL, in order to read the data from the memory cell QC1. Further, the external power supply voltage VCC is applied to a word line WL1 connected with the memory cell QC1.
In this case, leakage currents i0 flow in the bit line BL through the overerased memory cells QC2, QC3, QC4, . . . although the potentials of word lines WL2, WL3, WL4, . . . connected thereto are 0 V. As a result, the selected memory cell QC1, which is in a write state, is erroneously determined as being in an erase state although no current originally flows through this memory cell QC1. Thus, the presence of such overerased cells QC2, QC3, QC4, . . . is a critical defect in operation of the flash memory.
A DINOR (divided bit line NOR) flash memory dividing bit lines into sectors is now described.
U.S. Pat. No. 5,659,505 discloses the contents of such a DINOR flash memory. The contents are now briefly described.
FIG. 64 is a circuit diagram showing the structure of a memory cell array 6000 of a conventional DINOR flash memory.
As shown in FIG. 64, the memory cell array 6000 includes two memory cell array blocks BLK0 and BLK1. FIG. 64 representatively shows four memory cell transistors MC for each memory cell array block BLK0 or BLK1. The memory cell array block BLK0 includes memory cell transistors MC1a and MC1b having drains connected to a subbit line SBL1 respectively, memory cell transistors MC2a and MC2b having drains connected to a subbit line SBL2 respectively, a selector gate SG1 opening/closing connection between a main bit line BL1 and the subbit line SBL1, and a selector gate SG2 for opening/closing connection between a main bit line BL2 and the subbit line SBL2.
Control gate electrodes of the memory cell transistors MC1a and MC2a are connected to a word line WL1, and those of the memory cell transistors MC1b and MC2b are connected to a word line WL2.
The memory cell array block BLK1 also includes memory cell transistors MC3a and MC3b having drains connected to a subbit line SBL3 respectively, and memory cell transistors MC4a and MC4b having drains connected to a subbit line SBL4 respectively.
The memory cell array block BLK1 further includes a selector gate SG3 for opening/closing connection between the main bit line BL1 and the subbit line SBL3, and a selector gate SG4 for opening/closing connection between the main bit line BL2 and the subbit line SBL4.
Control gate electrodes of the memory cell transistors MC3a and MC4a are connected to a word line WL3, and those of the memory cell transistors MC3b and MC4b are connected to a word line WL4.
The DINOR flash memory performs write, erase and read operations for memory cells after selecting the corresponding memory cell array block BLK by opening/closing the corresponding selector gate SG. Each memory cell transistor MC is formed by a floating gate MOS transistor.
The erase and write operations of the DINOR flash memory are now described.
FIG. 65 illustrates threshold voltage distributions of memory cells of the DINOR flash memory with an external. power supply voltage VCC of 3.3 V.
In the erase operation, electrons are collectively injected into the floating gate electrode 5 by an F-N tunnel phenomenon on the overall channel surface. Thus, the threshold voltage Vth changes from a low level to a high level.
In the write operation, on the other hand, the electrons are extracted by an F-N tunnel phenomenon at the gate edge of the drain. Namely, low and high threshold voltage distribution sides are referred to as write and erase states respectively in the DINOR flash memory.
Further, the DINOR flash memory extracts the electrons by applying a pulse voltage bitwise and further repeats an operation (verify operation) of verifying the threshold voltage Vth, thereby narrowing the low threshold voltage side distribution. Consequently, the lower limit of the low threshold voltage side distribution exceeds 1.5 V, to implement the operation with the external power supply voltage VCC of 3.3 V.
On the other hand, there is such a tendency that a lower voltage operation, a lower power consumption operation and a higher-speed read operation are required to a nonvolatile semiconductor memory device.
FIG. 66 illustrates threshold voltage distributions of the memory cells of the DINOR flash memory with an external power supply voltage VCC of 1.8 V.
When the external power supply voltage VC is lower than the present value of 3.3 V (e.g., 1.8 V), the lower limit of the low threshold voltage side is reduced below 1.5 V as shown in FIG. 66, to result in the so-called overwritten cells. Consequently, it is conceivably difficult to implement a read operation employing the external power supply voltage VCC as such despite the aforementioned technique of the DINOR flash memory.
In order to solve this problem, conceivable is means of stepping up the low external power supply voltage VCC to about the present voltage level (3.3 V) in read operation for applying the stepped-up voltage to word lines.
When this means is applied, however, the read operation is retarded due to the time required for the steppe operation. Further, power consumption is increased due to the steppe operation. In addition, the number of circuits operating at 3.3 V is so increased that the effect of power consumption reduction by the low voltage of 1.8 V is disadvantageously reduced.
In the DINOR memory cell structure, further, non-selected memory cells (e.g., 63 memory cells) connected to a single subbit line generate a read leakage current as a whole.
When the power supply voltage VCC is 3.3 V, the lower limit of the write threshold voltage (Vth) distribution is 1.5 V, as shown in FIG. 65. When the threshold voltage Vth is written in a value of not more than 1.5 V, the total leakage current of 63 non-selected memory cells on the same bit line to which a control gate voltage Vcg of 0 V is applied reaches a value similar to a read current Iread to disable a correct read operation, resulting in an overwrite failure.
When the threshold voltage Vth of the memory cells is 1.5 V, a current corresponding to the read current Iread flows following application of a control gate voltage Vcg of 1.5 V thereto. FIG. 67 shows current-voltage characteristics in this case.
Referring to FIG. 67, symbol Ileak denotes the value of the leakage current of the aforementioned non-selected memory cells with the control gate voltage Vcg of 0 V.
Consider a characteristic value G, expressed in the following equation, indicating inclination of the current-voltage characteristics: EQU G=.differential.(log I)/.differential.Vcg
If memory cells increasing the characteristic value G are obtained, such memory cells have the current-voltage characteristics shown by dotted lines in FIG. 67, on the assumption that the leakage current Ileak remains unchanged under the control voltage Vcg of 0 V.
If such characteristics are obtained, no overwrite failure results even if the lower limit of the write threshold voltage distribution is 0.5 V. This is because the leakage current Ileak of non-selected memory cells remains unchanged regardless of the characteristics.
If the lower limit of the write threshold voltage distribution can be reduced, reduction of a read voltage is enabled, and reduction of the power supply voltage VCC is also enabled while maintaining a high-speed read operation with no step-up.
While the physical parameters of the memory cell transistors may be changed in order to increase the characteristic value G, no remarkable improvement can be expected even in this case.
FIG. 68 shows the relation between the control gate voltage Vcg and a source-to-drain current I flowing in a memory cell transistor.
As shown in FIG. 68, the characteristic value G under the read current Iread can be remarkably increased if the value of the read current Iread can be reduced.
In general, however, reduction of the read current Iread leads to reduction of a read speed.

Nonvolatile semiconductor memory device operable at high speed with low power supply voltage while suppressing increase of chip area


The application describes a method and system for controlling a processing of video data such that the video data may be transmitted over a connection in a communication network, where the connection employs a plurality of protocol layers. The processing of video data for transmission is performed at a first layer. A value or values of one or more transmission condition parameters indicative of transmission conditions in the network are acquired, where these transmission condition parameters are specific for a second layer provided lower than the first layer. Then one or more values of one or more video control parameters usable at the first layer are derived from the value of the least one transmission condition parameter and the processing of video data is performed in accordance with the derived one or more values.

Video transmission or video streaming within communication networks, such as ISDN networks or the Internet has become an important application of such communications networks. In the future, packet oriented mobile networks like GPRS (General Packet Radio Service) and UMTS (Universal Mobile Telephone Standard) will be commonly used to connect mobile users to fixed communication networks like the above-mentioned ISDN networks or the Internet. It is therefore important to employ efficient and intelligent support of high quality video streaming into wireless radio networks.
A radio channel is a critical resource since its bandwidth is limited. Furthermore, it is a highly unreliable data channel, which requires special techniques to obtain a desired quality-of-service. Additionally, packet switched wireless networks provide variable user data rates depending on the number of concurrently ongoing communications within the same cell.
In order to support data applications (such as file transfer etc.), which require a reliable data link, a combination of forward error correction (FEC) and retransmission-based automatic repeat request (ARQ) is commonly used.
Compared to reliable data transmission, video streaming has rather different requirements. Namely, video streaming is usually less sensitive against data losses, but very delay sensitive. Data transmissions have opposite characteristics, i.e. they are very sensitive to data loss, but not very sensitive to delay. In other words, in the case of video streaming, the loss of certain parts will lead to a certain deterioration of picture quality, which is usually tolerable to a certain degree, but a strong delay (as for example caused by packet retransmission) will require complicated buffering mechanisms and make real-time transmission impossible. Therefore, video streaming is typically conducted by adjusting appropriate parameters, such that the data rate of the video transmitter (for example a video coder) can be easily adapted to the available transmission bandwidth. For example, the input rate of video data into a coder can be controlled, the coding mode can be controlled, or the amount of overhead employed for error correction, such as forward error correction, can be controlled. Existing wireless transmission schemes in mobile networks neither address the special requirements of video streaming nor the advantages resulting from the ability to control the bit rate of a video data source in an appropriate and efficient way.

Method and system for controlling a processing of video data


A first conductivity type cladding layer 2, a first side multilayer 9, an active layer 4, a second side multilayer 10, and a second conductivity type cladding layer 3 are provided in a semiconductor light emitting device. The first side multilayer 9 is provided between the first conductivity type cladding layer 2 and the active layer 4, and the second side multilayer 10 is provided between the active layer 4 and the second conductivity type cladding layer 3. Each of the multilayer 9, 10 is transparent with respect to the light generated at the active layer 4, having a bandgap larger than that of the active layer 4, and lattice-matched with the active layer 4.

1. Field of the Invention
The present invention relates to a semiconductor light emitting device, in more particularly to a semiconductor light emitting device, in which a current spreading property can be improved without increasing a thickness of an active layer, a thickness of a semiconductor layer and an area of a first electrode.
2. Related Art
As to a light emitting diode (LED) which is a semiconductor light emitting device, it is possible to fabricate a high luminance LED emitting various color lights such as blue, green, orange, yellow, and red, since it is possible to grow a GaN based high quality crystal or an AlGaInP based high quality crystal by using MOVPE (Metal Organic Vapor Phase Epitaxy) method in recent years. In accordance with the provision of a high luminance light emitting diode, applications of the LED are widened, e.g. a back light of a liquid crystal display, a brake lump for a vehicle, so that demand for the LED increases year by year.
Since the growth of a high quality crystal by the MOVPE method has been achieved, a light emitting efficiency inside the light emitting device is nearing to a theoretical limit value. However, the light extract efficiency from the light emitting device to the outside is still low, and enhancement of the light extract efficiency is expected.
For example, a high luminance red LED is made from AlGaInP based materials, and has a double hetero structure comprising a conductive GaAs substrate, an n-type AlGaInP layer comprising an AlGaInP based material with a composition which is lattice-matched with the conductive GaAs substrate, a p-type AlGaInP layer, and an active layer which is a part of a light emitting part comprising AlGaInP or GaInP, and the active layer is sandwiched by the n-type AlGaInP layer and the p-type AlGaInP layer. The AlGaInP based material here is a general term of various kinds of materials mainly comprising AlGaInP, in that composition ratios or additives are different from each other. In the semiconductor light emitting device using AlGaInP based material, materials such as GaInP, GaP may be used together.
Since a bandgap of the GaAs substrate is narrower than that of the active layer in such a semiconductor light emitting device, most of the light emitted from the active layer is absorbed by the GaAs substrate, so that the light extract efficiency is deteriorated.
As means for solving this problem, there is a technique for improving the light extract efficiency by forming a layer with a multilayer reflective film structure comprising semiconductors having different refractive indices between the active layer and the GaAs substrate to reflect the light emitted to the GaAs substrate, thereby reducing an absorption of the light in the GaAs substrate. However, according to this technique, only the light having a limited incident angle with respect to the multilayer reflective film structure layer is reflected. In other words, only a part of the light emitted to the GaAs substrate is reflected, so that it is difficult to improve the light extract efficiency enough.
Thus, Japanese Patent Laid-Open No. 2002-217450 discloses another technique for realizing a high luminance by manufacturing a semiconductor light emitting device in which a double hetero structure part comprising AlGaInP based material is grown on a GaAs substrate for growth, sticking the double hetero structure part on a supporting substrate such as Si or GaAs thereafter via a metal layer with a high reflectance, and removing the GaAs substrate used for the growth. According to this technique, since the metal is used as a reflective layer, the reflection with high reflectance can be realized without selecting an incident angle with the reflective layer. For this reason, it is possible to provide a higher luminance than the aforementioned technique in which the multilayer reflective film structure is formed. In other words, it is possible to achieve the higher luminance by extracting the light generated in the active layer more effectively.
In the conventional semiconductor light emitting device, a thickness of the semiconductor layer (epitaxial layer) is increased to improve the current spreading, thereby realizing the high luminance. However, in the semiconductor light emitting device in which the high luminance is achieved by effectively reflecting a light at a reflective metal film, a step for removing and sticking a substrate is required, so that the thickness of the semiconductor layer cannot be much increased. When the thickness of the semiconductor layer is increased, a warping of the epitaxial wafer is also increased, so that it is difficult to conduct the step of removing and sticking the substrate, thereby deteriorating a production yield.
Further, there is a disadvantage in a material cost when the thickness of the semiconductor layer is increased.
So as to solve this problem, as a technique for improving the current spreading (current dispersion) without increasing the thickness of the semiconductor layer, a configuration in which a first electrode comprises a narrow wire electrode is proposed. According to this structure, the current spreading can be improved in accordance with an increase in an area of the first electrode by using the narrow wire. However, there is disadvantage in that the light is difficult to be extracted to the outside, since an area of a shadow of the first electrode is increased. Namely, there is a trade-off relationship between the current spreading and the light extract. In more concrete, the change in the area of the first electrode is affected by the trade-off relationship between the improvement in the current spreading and the increase in the shadow of the first electrode.
In the semiconductor light emitting device, in which the high luminance is achieved by effective reflecting the light at the reflective metal film, the light emitted from the active layer is reflected at the reflective metal film and transmitted again through the active layer. However, since the active layer is not perfectly transparent with respect to the emitted light, the light reflected at the reflective metal film is absorbed in the active layer to some extent. So as to reduce the absorption of the light, it is desirable to reduce a thickness of the active layer. However, when the thickness of the active layer is excessively reduced, there is a disadvantage in that the light output is deteriorated due to an overflow of carriers.