A data transmission system comprises a data transmission apparatus for transmitting plural pieces of object data for reproducing plural objects constituting a scene, and a data receiving apparatus for receiving the plural pieces of object data and reproducing the scene on the basis of the object data. The data transmission apparatus comprises a first transmission unit for transmitting first object data, amongst the plural pieces of object data, such that reproduction of the scene is performed at the receiving end on the basis of the first object data after the transmission of the first object data has been completed, and a second transmission unit for transmitting second object data other than the first object data, amongst the plural pieces of object data, such that reproduction of the scene is performed at the receiving end on the basis of the second object data during the transmission of the second object data.

The present invention relates to a data transmission method, a data transmission system, a data receiving method, and a data receiving apparatus and, more particularly, to a method for transmitting image data of MPEG4, through the Internet, according to a transmission mode adapted to the type of the image data.
In recent years, we have greeted the age of multimedia in which audio, video, and other data are integrally handled, and the conventional information media, i.e., means for transmitting information to men, such as newspapers, magazines, televisions, radios, and telephones, have been adopted as the targets of multimedia. Generally, xe2x80x9cmultimediaxe2x80x9d means media in which, not only characters, but also diagrams, speeches, and especially images are simultaneously expressed in relation with each other. In order to handle the conventional information media as the targets of multimedia, it is necessary to represent the data in digital formats.
When the quantity of data possessed by each of the above-described information media is estimated as the quantity of digital data, in the case of characters, the data quantity per character is only 1xcx9c2 byte. However, in the case of speech, the data quantity is 64 kbits per second (quality for telecommunication). Further, in the case of moving picture, the required data quantity is more than 100 Mbits per second (quality for current television broadcasting). So, in the above-described information media, it is not practical to handle such massive data as it is in the digital format. For example, although visual telephones have already been put to practical use by the ISDN (Integrated Services Digital Network) having a transmission ratio of 64 kbpsxcx9c1.5 Mbps, it is impossible to transmit an image from a television camera as it is by the ISDN.
So, data compression techniques are demanded. For example, for visual telephones, the moving picture compression techniques based on the H.261 and H.263 standards which have been standardized by ITU-T (International Telecommunication Unionxe2x80x94Telecommunication Sector) are employed. Further, according to the data compression technique based on the MPEG1 standard, it is possible to record image data as well as audio data in an ordinary music CD (compact disk).
MPEG (Moving Picture Experts Group) is an international standard relating to a data compression technique for an image signal corresponding to a moving picture, and MPEG1 is the standard for compressing moving picture data to 1.5 Mbps, i.e., data of a television signal to about {fraction (1/100)}. Since the transmission rate of the targets to which the MPEG1 standard is directed is limited to about 1.5 Mbps, in MPEG2 which has been standardized to meet the demand for higher image quality, moving picture data is compressed to 2xcx9c15 Mbps.
Furthermore, under the existing circumstances, standardization of MPEG4 is now proceeded by the working group for standardization of MPEG1 and MPEG2 (ISO/IEC JTC1/SC29/WG11), and this MPEG4 enables coding and signal processing in object units, and hereby realizes new functions required in the age of multimedia.
FIGS. 7, and 8(a)-8(d) are diagrams for explaining the object-by-object coding process.
In MPEG4, an image G corresponding to one frame shown in FIG. 7 is treated as a composite image which is obtained by compositing plural objects. The image G is composed of a background B (FIG. 8(a)), a big fish F1 as a first foreground (FIG. 8(b)), a small fish F2 as a second foreground (FIG. 8(c)), and a seaweed F3 as a third foreground (FIG. 8(d)).
Further, in the object-by-object coding process based on MPEG4, image data corresponding to the respective objects constituting the composite image G (the background B and the first to third foregrounds F1xcx9cF3) are encoded object by object. Then, coded image data (object data) corresponding to the respective objects are transmitted through a transmission medium.
On the other hand, in the object-by-object decoding process based on MPEG4, the coded image data corresponding to the respective objects are received object by object or in the multiplexed state, through the transmission medium. The received coded image data are decoded object by object, thereby generating decoded image data corresponding to each object. Then, the decoded image data corresponding to the respective objects are composited, thereby generating reproduced image data (scene data) corresponding to the composite image (decoded and reproduced image) G.
In the above-described process for transmitting the object-by-object coded image data, not only the coded image data (object data) obtained by coding the image data object by object but also control information are transmitted through the transmission medium. The control information includes, for example, scene description information which indicates the locations of the respective objects in one frame for compositing and displaying the objects, i.e., the display area of the composite image (refer to FIG. 15(b)).
Meanwhile, in recent years, a video distribution system has spread, in which the user can gain access to his/her favorite moving picture through a computer network.
FIG. 9 is a schematic diagram for explaining such video distribution system.
In a video distribution system 700, a plurality of networks 701, 702 and 703 are connected to each other, and a plurality of servers 705, 706 and 707 which distribute video information are connected to the networks 701, 702 and 703, respectively. Further, a plurality of video reception and reproduction terminal units (hereinafter referred to simply as xe2x80x9cterminal unitsxe2x80x9d) which receive the distributed video information are connected to the respective networks 701xcx9c703. To simplify the description, only a terminal unit 704 connected to the network 701 is shown in FIG. 9.
In the video distribution system 700 so constructed, when the terminal unit 704 receives video information distributed from the server 705, initially, the terminal unit 704 contacts the server 705, and effectuates a circuit connection with the server 705. Thereafter, the terminal unit 704 receives coded image data distributed from the server 705, and reproduces the image data by decoding.
Hereinafter, a description will be given of a specific process of obtaining predetermined image data through the Internet as the above-described network.
As described above, a plurality of information sources (servers) are connected to the Internet which forms the network in the current information distribution system, and the respective information sources contain, for example, information of home pages relating to various subjects. Now it is assumed that the terminal unit 704 is connected to an information source having information of a home page HP the title of which is xe2x80x9cWorld of Dinosaursxe2x80x9d, and this home page HP is displayed on a display of the terminal unit 704.
In this home page HP, as shown in FIG. 10, items of video scenes relating to dinosaurs are represented by character strings xe2x80x9cscene 1xe2x80x9dxcx9cxe2x80x9cscene 3xe2x80x9d, and the display areas of these character strings are designation areas D1xcx9cD3 for designating the moving pictures. In this state, the user moves the mouse pointer MP to the designation area D1 corresponding to the character string xe2x80x9cscene 1xe2x80x9d in the home page HP and clicks the mouse, an image MPs of a video scene P linked to the character string xe2x80x9cscene 1xe2x80x9d is displayed as shown in FIG. 11(a).
As a data transmission method for transmitting the image (text, audio, and video) data on the Internet, download type transmission and stream type transmission are currently employed.
In the download type transmission, a video file (image data) transmitted from a distribution server is once copied at the terminal and, thereafter, the image corresponding to the video file is reproduced. So, the terminal cannot start image reproduction until the file transmission is completed. That is, there is a latency time for transmission and, therefore, the download type transmission is not suitable for long-hours reproduction of video and audio. On the other hand, in the stream type transmission, while transmitting video data or the like from the distribution server to the terminal, image reproduction is carried out on the basis of the received data at the terminal end.
Therefore, data to be processed in real time, such as video data and audio data, are transmitted by the stream type transmission.
Recently, stream type transmission using a protocol called RTP (Real-time Transport Protocol) has been mainly employed. In a communication system in which a distribution server (transmitting end) S and a terminal (receiving end) T such as a personal computer are connected by a circuit such as ISDN in the Internet as shown in FIG. 16, transmission of image data is performed according to the RTP.
In the data transmission according to the RTP, processes for the respective packets are synchronized between the transmitting end and the receiving end by using time stamps as time information, and asynchronous (late arrival) packets and error packets in which transmission errors have occurred are discarded at the receiving end. Further, discarded or lost packets are detected at the receiving end, according to the absences of sequence numbers given to these packets.
Under the circumstances described above, in recent years, a method for transmitting image data of MPEG4 through the Internet has been examined.
In MPEG4, the video scene P shown in FIG. 11(a) is treated as a composite image G1 which is composed of four objects ob1, ob2, ob3, and ob4 (refer to FIG. 11(b)). That is, in this composite image G1, the object ob1 is a background as a still picture showing the sky or the like (FIG. 12(a)), the object ob2 is a first foreground as a cyclic moving picture showing a volcano (FIG. 12(b)), the object ob3 is a second foregound as a moving picture showing a big dinosaur (FIG. 12(c)), and the object ob4 is a third foreground as a moving picture showing a small dinosaur (FIG. 12(d)).
Hereinafter, a data transmission method based on MPEG4, which is currently examined, will be described by using FIGS. 15(a) and 15(b). In the following description, a plurality of servers may be connected to the terminal T.
In this data transmission method, image data corresponding to one scene (composite image) treated in MPEG4 is obtained for each of plural objects constituting the scene, from a predetermined server, by the RTP, through the Internet.
Initially, as already described with respect to FIG. 10, in the state where the home page HP is displayed on the display unit of the terminal T, when the user clicks the mouse at the designation area D1 corresponding to the character string xe2x80x9cscene 1xe2x80x9d, a session description protocol (SDP) (FIG. 13(a)) and an initial object descriptor (IOD) (FIG. 13(b)), which correspond to the scene (composite image) G1 and are linked to the character string xe2x80x9cscene 1xe2x80x9d, are transmitted from the server S containing these data to the terminal T through the Internet (refer to FIG. 9).
With reference to FIG. 13(a), in the SDP (hereinafter also referred to as SDP information), the type of data is described in association with a transmission mode and a URL (Uniform Resource Locator) of the data, which are required for reproduction of the composite image. To be specific, as the above-mentioned data, there are not only the object data (entity data) for reproducing the respective objects constituting the scene, i.e., image data, audio data, and text data, but also control information, i.e., an initial object descriptor (IOD), an object descriptor stream (ODS), and a scene description stream (SDS).
Further, as shown in FIG. 13(b), in the initial object descriptor (hereinafter also referred to as IOD information), data of the object descriptor (OD) corresponding to the ODS itself, and data of the object descriptor (OD) corresponding to the SDS itself, are stored.
Further, as shown in FIG. 14(a), in the ODS (hereinafter also referred to as ODS information), data of object descriptors (OD) of all objects constituting the scene are stored. Further, as shown in FIG. 14(b), in the SDS (hereinafter also referred to as SDS information), data of scene descriptions SD1xcx9cSDn corresponding to predetermined times t1xcx9ctn are stored.
When the SDP information and the IOD information are transmitted to the terminal T, the terminal T requests the server S to transmit the ODS information corresponding to the respective objects (i.e., object descriptors OD1xcx9cOD4) and the entity data, by specifying their uniform resource locators (URL) and synchronization sources (hereinafter referred to simply as SSRC). Further, the terminal T requests the server S to transmit the SDS information corresponding to the scene G1 (i.e., the scene descriptions SD1xcx9cSDn), by specifying the URL and SSRC. The SSRC is a channel ID for identifying a channel of the RTP packet.
On receipt of the request from the terminal T, the server S packetizes the requested data, gives the SSRC specified by the terminal to each packet, and transmits the packets to the terminal T according to the RTP.
The terminal T receives the image data (object data) of the respective objects constituting the scene G1, the object descriptors OD1xcx9cOD4, and the scene descriptions SD1xcx9cSDn. Based on these data, the terminal T reproduces and displays the image of the scene G1.
FIG. 15(a) shows the specific contents of the object descriptor OD1 (id=100), and FIG. 15(b) shows the specific contents of the scene description SD1 (time t1).
However, the image data according to MPEG4 includes data (control information) which prevents image reproduction if a transmission error occurs in this data, such as the SDP information, the IOD information, the SDS information, and the ODS information. When such data (control information) is transmitted according to the RTP, since recovery against the transmission error is not performed, the state where the image data cannot be reproduced, occurs frequently at the receiving end.
Further, when download type transmission and the stream type transmission are performed in arbitrary order, the image data are sometimes transmitted by the download transmission while reproducing the image data transmitted by the stream type transmission. In this case, the data transmission quantity during scene reproduction increases significantly, and the consumption of the transmission band of the network cannot be minimized.
Further, although the number of the objects constituting he scene and the hierarchy of the objects can be grasped from the SDS information and the ODS information, the correspondence between the address (URL) of the object data (image data corresponding to each object) and each object cannot be obtained.
The present invention is made to solve the above-described problems and has for its object to provide a data transmission method, a data transmission system, a data receiving method, and a data receiving apparatus, which avoid unreliability of image reproduction at a receiving terminal due to transmission error, and assure reliable image reproduction at the receiving terminal even when some transmission error occurs.
It is another object of the present invention to provide a data transmission method, a data transmission system, a data receiving method, and a data receiving apparatus, which prevent data transmission quantity during from increasing considerably scene reproduction, and thereby minimize the consumption of the transmission band of the network.
It is still another object of the present invention to provide a data transmission method, a data transmission system, a data receiving method, and a data receiving apparatus, in which each object can be associated with the URL (Uniform Resource Locator) of image data corresponding to the object, on the basis of the SDP (Session Description Protocol) corresponding to the scene.
Other objects and advantages of the invention will become apparent from the detailed description that follows. The detailed description and specific embodiments described are provided only for illustration since various additions and modifications within the scope of the invention will be apparent to those of skill in the art from the detailed description.
According to a first aspect of the present invention, there is provided a data transmission method of transmitting plural pieces of object data for reproducing plural objects constituting a scene, from the transmitting end to the receiving end. This method comprises a first transmission process of transmitting first object data, among the plural pieces of object data, such that reproduction of the scene is performed at the receiving end on the basis of the first object data after the transmission of the first object data has been completed; and a second transmission process of transmitting second object data other than the first object data, among the plural pieces of object data, such that reproduction of the scene is performed at the receiving end on the basis of the second object data during the transmission of the second object data. Therefore, extreme increase in the data transmission quantity during scene reproduction is avoided, and the consumption of the transmission band of the network is minimized.
According to a second aspect of the present invention, there is provided a data transmission method for transmitting scene data for reproducing a scene, from the transmitting end to the receiving end. This method comprises a first transmission process of transmitting first data which is a part of the scene data, in accordance with a first transmission protocol which does not necessarily perform retransmission against transmission errors; and a second transmission process of transmitting second data which is a part of the scene data, in accordance with a second transmission protocol which performs retransmission against transmission errors. The second data is scene description information and object relevant information, the scene description information indicating the hierarchy of the respective objects constituting the scene, by object identifiers which are given to the respective objects for identifying these objects, and the object relevant information indicating additional information relating to the respective objects, in association with the object identifiers of the respective objects. Therefore, this method can prevent image reproduction at the receiving end from becoming unreliable due to transmission error, and the receiving end can perform reliable image reproduction even when some transmission error occurs.
According to a third aspect of the present invention, there is provided a data transmission method for transmitting scene data for reproducing a scene, from the transmitting end to the receiving end. This method comprises the steps of transmitting object data for reproducing plural objects constituting the scene, object by object, from the transmitting end to the receiving end; and transmitting table information from the transmitting end to the receiving end, the table information associating an object identifier given to each object for identifying the object, with location information indicating the location of object data corresponding to the object. Therefore, the receiving end can associate each object with the location of object data corresponding to the object, on the basis of the table information.
According to a fourth aspect of the present invention, there is provided a data transmission system comprising a data transmission apparatus for transmitting plural pieces of object data for reproducing plural objects constituting a scene; and a data receiving apparatus for receiving the plural pieces of object data and reproducing the scene on the basis of the object data. The data transmission apparatus comprises a first transmission unit for transmitting first object data, among the plural pieces of object data, such that reproduction of the scene is performed at the receiving end on the basis of the first object data after the transmission of the first object data has been completed; and a second transmission unit for transmitting second object data other than the first object data, among the plural pieces of object data, such that reproduction of the scene is performed at the receiving end on the basis of the second object data during the transmission of the second object data. Therefore, extreme increase in the data transmission quantity during scene reproduction is avoided, and the consumption of the transmission band of the network is minimized.
According to a fifth aspect of the present invention, in the data transmission system of the fourth aspect, the data transmission apparatus transmits, by using the first transmission unit, control information for controlling transmission of the object data and reproduction of the objects, as initial data to be transmitted to the receiving end in the transmission process for data corresponding to one scene, the control information including transmission mode identification information indicating that the object data corresponding to each of the objects constituting one scene is to be transmitted by the first transmission unit or the second transmission unit. Therefore, in addition to the effect of minimizing the consumption of the transmission band of the network, this system can prevent image reproduction at the receiving end from becoming unreliable due to transmission error.
According to a sixth aspect of the present invention, there is provided a data transmission system comprising a data transmission apparatus for transmitting scene data for reproducing a scene; and a data receiving apparatus for receiving the scene data and reproducing the scene. The data transmission apparatus comprises a first transmission unit for transmitting first data which is a part of the scene data, in accordance with a first transmission protocol which does not necessarily perform retransmission against transmission errors; and a second transmission unit for transmitting second data which is a part of the scene data, in accordance with a second transmission protocol which performs retransmission against transmission errors. The second transmission unit transmits, as the second data, scene description information and object relevant information, the scene description information indicating the hierarchy of the respective objects constituting the scene, by object identifiers which are given to the respective objects for identifying these objects, and the object relevant information indicating additional information relating to the respective objects, in association with the object identifiers of the respective objects. Therefore, this system can prevent image reproduction at the receiving end from becoming unreliable due to transmission error, and the receiving end can perform reliable image reproduction regardless of some transmission error.
According to a seventh aspect of the present invention, there is provided a data transmission system comprising a data transmission apparatus for transmitting, object by object, object data for reproducing plural objects constituting a scene; and a data receiving apparatus for receiving the object data and reproducing the scene on the basis of the object data. The data transmission apparatus comprises an information transmission unit for transmitting table information which associates an object identifier given to each object for identifying the object, with location information indicating the location of object data corresponding to the object. Therefore, the receiving end can associate each object with the location of object data corresponding to the object, on the basis of the table information.
According to an eighth aspect of the present invention, in the data transmission system of the seventh aspect, the information transmission unit transmits the table information in such a manner that the table information is included in control information for controlling transmission of the object data and reproduction of the objects, the control information being initial information to be transmitted to the receiving end in the transmission process for data corresponding to the scene. Therefore, the receiving end can associate each object with the location of object data corresponding to the object, on the basis of the table information.
According to a ninth aspect of the present invention, in the data transmission system of the seventh aspect, the information transmission unit transmits the table information in such a manner that the table information is included in object relevant information which indicates additional information relating to the respective objects in association with object identifiers of the respective objects. Therefore, the receiving end can associate each object with the location of object data corresponding to the object, on the basis of the table information.
According to a tenth aspect of the present invention, there is provided a data receiving method for receiving plural pieces of object data for reproducing plural objects constituting a scene, transmitted from the transmitted end, and reproducing the scene on the object data. This method comprises a first receiving process of receiving first object data among the plural pieces of object data, and reproducing the scene on the basis of the first object data after the reception of the object data has been completed; and a second receiving process of receiving second object data other than the first object data among the plural pieces of object data and, simultaneously reproducing the scene on the basis of the second object data. Therefore, extreme increase in the data transmission quantity during scene reproduction is avoided, and the consumption of the transmission band of the network is minimized.
According to an eleventh aspect of the present invention, there is provided a data receiving method for receiving scene data for reproducing a scene, transmitted from the transmitting end, and reproducing the scene. This method comprises a first receiving process of receiving first data which is a part of the scene data, transmitted according to a first transmission protocol which does not necessarily perform retransmission against transmission errors; and a second receiving process of receiving second data which is a part of the scene data, transmitted according to a second transmission protocol which performs retransmission against transmission errors. The second data is scene description information and object relevant information, the scene description information indicating the hierarchy of the respective objects constituting the scene, by object identifiers corresponding to the respective objects, and the object relevant information indicating additional information relating to the respective objects, in association with the object identifiers of the respective objects. Therefore, this method can prevent image reproduction at the receiving end from becoming unreliable due to transmission error, and satisfactory scene reproduction is performed regardless of some transmission error.
According to a twelfth aspect of the present invention, there is provided a data receiving method for receiving scene data for reproducing a scene, transmitted from the transmitting end, and reproducing the scene. This method comprises the steps of receiving object data for reproducing plural objects reconstituting the scene, which are transmitted object by object from the transmitting end; and receiving table information transmitted from the transmitting end, the table information associating an object identifier given to each object for identifying the object, with location information indicating the location of object data corresponding to the object. Therefore, during scene reproduction, each object can be associated with the location of object data corresponding to the object, on the basis of the table information.
According to a thirteenth aspect of the present invention, there is provided a data receiving apparatus for receiving plural pieces of object data for reproducing plural objects constituting a scene, transmitted from the transmitting end, and reproducing the scene on the basis of the object data. This apparatus comprises a first receiving unit for receiving first object data among the plural pieces of object data; a second receiving unit for receiving second object data other than the first object data among the plural pieces of object data; and a reproduction unit for reproducing the scene on the basis of the first object data and the second object data, in which scene reproduction based on the first object data is performed after reception of the first object data has been completed, while scene reproduction based on the second object data is performed in parallel with the reception of the second object data. Therefore, extreme increase in the data transmission quantity during scene reproduction is avoided.
According to a fourteenth aspect of the present invention, in the data receiving apparatus of the thirteenth aspect, control information for controlling transmission of the object data and reproduction of the objects is received by the first receiving unit, as initial data transmitted to the receiving end in the transmission process for data corresponding to the scene; and the object data corresponding to each object is received by one of the first and second receiving units, according to transmission mode identification information which is included in the control information and indicates that the object data is to be received by the first receiving unit or the second receiving unit. Therefore, in addition to the effect of minimizing the consumption of the transmission band of the network, this apparatus can prevent image reproduction at the receiving end from becoming unreliable due to transmission error.
According to a fifteenth aspect of the present invention, there is provided a data receiving apparatus for receiving scene data for reproducing a scene, transmitted from the transmitting end, and reproducing the scene. This apparatus comprises a first receiving unit for receiving first data which is transmitted as a part of the scene data in accordance with a first transmission protocol that does not necessarily perform retransmission against transmission errors; a second receiving unit for receiving second data which is transmitted as a part of the scene data in accordance with a second transmission protocol that performs retransmission against transmission errors. The second receiving unit receives, as the second data, scene description information and object relevant information, the scene description information indicating the hierarchy of the respective objects constituting the scene, by object identifiers corresponding to the respective objects, and the object relevant information indicating additional information relating to the respective objects, in association with the object identifiers of the respective objects. Therefore, this apparatus can prevent image reproduction at the receiving end from becoming unstable due to transmission error.
According to a sixteenth aspect of the present invention, there is provided a data receiving apparatus for receiving object data for reproducing objects constituting a scene, transmitted object by object from the transmitting end, and reproducing the scene. This apparatus comprises a first receiving unit for receiving first data which is transmitted as a part of the scene data in accordance with a first transmission protocol that does not necessarily perform retransmission against transmission errors; and a second receiving unit for receiving second data which is transmitted as a part of the scene data in accordance with a second transmission protocol that performs retransmission against transmission errors. The second receiving unit receives, as the second data, table information transmitted from the transmitting end, the table information associating an object identifier given to each object for identifying the object, with location information indicating the location of object data corresponding to the object. Therefore, even when some transmission error occurs, each object can be associated with the location of object data corresponding to the object on the basis of the table information.
According to a seventeenth aspect of the present invention, in the data receiving apparatus of the sixteenth aspect, the second receiving unit receives the table information as information included in control information for controlling transmission of object data corresponding to the respective objects and reproduction of the objects, the control information being received first as the scene data corresponding to one scene. Therefore, even when some transmission error occurs, each object can be associated with the location of object data corresponding to the object on the basis of the table information.
According to an eighteenth aspect of the present invention, in the data receiving apparatus of the sixteenth aspect, the second receiving unit receives the table information as information included in object relevant information transmitted from the transmitting end, the object relevant information indicating additional information relating to the respective objects, in association with object identifiers of the respective objects. Therefore, even when some transmission error occurs, each object can be associated with the location of the object data corresponding to the object on the basis of the table information.

Data transmission method, data transmission system, data receiving method, and data receiving apparatus

Matsushita Electric Industrial Co., Ltd.


A container for collecting body fluids comprising, a receptacle having a cavity, and a siphon assembly having a pair of opposed spaced walls defining a chamber, a port communicating with the chamber to receive the fluids, and a siphon passageway. The passageway has an upper portion spaced a substantial distance above a lower portion of the chamber and located below an upper portion of the chamber, a first portion connecting the passageway upper portion to the lower portion of the chamber, and a second portion extending downwardly from the passageway upper portion and communicating with the receptacle cavity.

The present invention relates to liquid drainage systems, and more particularly to liquid collection receptacles.
In the past, catheters have been used to drain urine from a patient's bladder. In such a procedure, a distal end of the catheter, such as a Foley catheter, is inserted through the patient's urethra into the bladder, and a retention balloon adjacent the distal end of the catheter is inflated in the bladder to retain the catheter in place. The catheter has a drainage eye adjacent the distal end of the catheter communicating with a drainage lumen extending from the drainage eye to a proximal end of the catheter which remains outside the patient's body during use of the catheter. Accordingly, urine drains from the bladder through the drainage eye and lumen to the proximal end of the catheter after which the urine is collected in a receptacle.
On occasion it is necessary to drain urine directly from one or both of the patient's ureters or kidneys. For example, subsequent to certain ureterotomy procedures a ureteral catheter is passed through the urethra, bladder, and ureterovesicle junction, such that drainage eyes in the ureteral catheter are located upstream from the surgical site, and possibly in the enlarged renal pelvis adjacent the kidney. Urine drains through the drainage eyes and a drainage lumen extending through the ureteral catheter to a proximal end of the catheter outside the patient's body for collection of the urine. Thus, contact of a substantial amount of urine against the surgical site in the ureter is prevented. The Foley catheter is simultaneously used to drain urine passing from the uncatheterized ureter into the bladder and to drain any residual urine from the catheterized ureter which might eventually leak between the catheter and the ureter.
In the event that surgery has been performed on both ureters a second ureteral catheter is placed in the other ureter, and urine drains through both ureteral catheters, while residual urine is drained from the bladder through the Foley catheter, which may also be utilized to stabilize the ureteral catheters. A pair of ureteral catheters may also be used after surgery on the bladder to prevent urine from passing into the bladder. Similarly, ureteral catheters may be used for both ureters during a partial differential study, where the relative output of urine from both kidneys is determined.

Collection container with siphon assembly


A power plant includes a primary and a secondary power cycle, with the secondary power cycle including a thermal reservoir adapted for the absorption of heat rejected from the primary power cycle during the simultaneous generation of power from the secondary power cycle. Heat is withdrawn from the thermal reservoir during periods of reduced power demand, allowing latitude in the scheduling of heat rejection from the power plant.

This invention relates generally to energy storage for the load leveling of power plants, and more particularly to load leveling storage schemes which simultaneously reduce the rate of peak heat rejection of an associated power plant.
The demand for electricity from a power system typically varies between a given base load and a higher peak rate. To accommodate this varying demand electrical power systems have historically operated their most efficient power plants in a constant "base loaded" mode and have added additional power plants to the system power grid as demand increases in order of decreasing power plant efficiency, with the least efficient plant being the last added.
More recently, load leveling systems involving the storage of energy have been introduced as a means of avoiding the use of less efficient power plants during periods of peak power demand, as well as to allow existing power plants to operate in the efficient "base loaded" mode while avoiding the addition of costly new peaking power plants. These load leveling systems typically involve the storage of energy (mechanical, electrical or thermal) in some reservoir during off-peak hours and withdrawing it during hours of greater need. The scarcity of suitable sites for pumped hydro-storage schemes and the projected high cost of electrical storage has resulted in a growing interest in thermal storage.
Conventional thermal storage systems include steam storage, hot water storage, and thermal storage in hot oil reservoirs. However, each of these conventional thermal storage systems requires that the stored thermal energy be withdrawn and converted to a useable form of energy during periods of peak power demand, thereby resulting in an increase in the peak heat rejection rate of the associated power plant.
The accommodation of this increased rate of peak heat rejection typically requires the construction and use of additional plant capacity to transfer the rejected heat to a heat sink. This additional capacity may be in the form of larger cooling towers, spray ponds, or the like. As a result, power plant construction, operating and maintenance costs are all significantly increased in power plants utilizing conventional thermal storage systems.
Accordingly, it is an object of the present invention to provide a new and improved method and system for increasing the deliverable peak power of a power plant while simultaneously reducing the rate of heat rejection typically associated with peak power production.
Thus, through the practice of the present invention a power plant intended to meet a given peak load can be designed with a primary power cycle having an output below the intended plant peak power output. Similarly, such a plant could include a rejected heat transfer capacity less than that required for a typical power plant of equal design peak power output, especially if compared to a power plant employing a conventional thermal storage system. Accordingly, the savings in capitol costs as well as in operating and maintenance costs resulting from the practice of the present invention are significant. Of course, it is appreciated that these benefits are not limited to electrical power systems, and that similar savings are obtainable with other power plants operating to satisfy variable power demands.

Means and method for simultaneously increasing the delivered peak power and reducing the rate of peak heat rejection of a power plant


A mobile communicator consisting of a wrist strap and an actual combined mobile communicator connected to the strap which includes at least two separate mobile communicator parts. The parts of the mobile communicator are mechanically connected by joints so that they can be folded inwardly against one another in repose position and can be opened profitably sequentially and in parallel when in a usage position. The mobile communicator parts are arranged to be opened outwardly for use in essentially a vertical direction compared with the plane of the wrist strap.

1. Field of the Invention
The present invention relates to a foldable mobile wrist communicator according to the preamble of the patent claim 1. Mobile communicator here means also wireless telephones on the whole.
2. Description of the Prior Art
The patent publication U.S. Pat. No. 5,274,613 presents a watch and a radio telephone mounting on a wrist strap. In the prior art solution a watch and a mobile radio communicator are located in a foldable unit, which can be attached to or disconnected from a wrist strap. The foldable unit is opened out so that the topmost part of the foldable unit pivots out to the left and the middle part to the right as seen from the left hand while the bottom part remains in its initial position. That is to say the foldable unit pivots out tangent to the wrist strap i.e. perpendicular to the arm line. When unfolded the unit functions as a radio telephone which has a microphone on one end and an earphone on the other end of the opened unit.
However, the prior art solution has its disadvantages. Whole electronics has been planned to be inserted in one wrist strappable unit. In this way the unit becomes large and heavy, which makes the usage of the unit on the wrist strap quite inconvenient. Especially the power unit solutions of the mobile communicators still today are of the size and weight class, which are very difficult to fit together with the unit in question. One notable disadvantage is also that because the current supply is fixed when the current supply runs low, the watch and the mobile communicator are out of order till the current supply has been charged again.
The radio mobile communicator of the prior art opens out to a very inconvenient position when it is used on the wrist. When the longitudinal direction is perpendicular to the longitudinal direction of the arm talking to the phone and other usage of the radio telephone is difficult because irrespective of whether the opened out mobile communicator is located inside or outside of the wrist the user must always hold his hand in an unnatural position as he speaks to the phone. In addition, when the watch and the radio telephone are combined it is impossible to use and carry them separately only one at a time.


A salt of a mono- and/or dialkyl ester of a sulfonated dicarboxylic acid is provided, where the dicarboxylic acid contains 4 to 8 carbon atoms and the alkyl groups are derived from 2-propylheptanol. A composition including (a) one or more salt(s) of a mono- and/or dialkyl ester(s) of a sulfonated dicarboxylic acid(s), where the dicarboxylic acid contains 4 to 8 carbon atoms and the alkyl groups are derived from 2-propylheptanol; and (b) one or more organic solvents liquid at 20° C. with a boiling point above 250° C. at 1 bar is also provided.

1. Field of the Invention
The invention relates generally to salts of mono- and dialkyl esters of sulfonated dicarboxylic acids, and more particularly to compounds and compositions including salts of mono- and dialkyl esters of sulfonated dicarboxylic acids, wherein the dicarboxylic acids contain 4 to 8 carbon atoms and the alkyl groups are derived from 2-propylheptanol, and to the use of the salts.
2. Background Information
Salts of mono- and dialkyl esters of sulfonated dicarboxylic acids have been known for some time. They are also known as mono- and disulfosuccinates, respectively, and are used as surfactants inter alia in emulsion polymerization, as wetting agents for paints, for coating paper and paperboard and for pharmaceutical purposes (cf. for example the synoptic article by Breuer, W. and Höfer, R. in Tenside, Surfactants, Detergents, 2003, 40 (4), 208-214).
By virtue of its favorable properties, including for example the low dynamic surface tension of aqueous solutions, the sodium salt of di-2-ethylhexyl sulfosuccinate in particular is widely used. However, for production-related reasons and in consequence of ester cleavage reactions, the corresponding formulations contain free, i.e., unbound, 2-ethyl hexanol. In view of its unpleasant odor and taste, this free 2-ethylhexanol is a disadvantage for many applications, particularly in the food industry. In addition, both 2-ethylhexyl alcohol and the sodium salt of di-2-ethylhexyl sulfosuccinate are classified as water hazards (Water Hazard Class 2).

Salts of alkyl esters of sulfonated dicarboxylic acids and compositions containing same


The present invention relates to a method of fabricating a MOS transistor on a semiconductor wafer. The semiconductor wafer comprises a silicon substrate. A gate is first formed in a predetermined area on the surface of the semiconductor wafer. A first ion implantation process is then performed to form a doped area on the surface of the silicon substrate adjacent to the gate, the doped area serving as a heavily doped drain (HDD). A uniform and oxygen-free dielectric layer is formed on the surface of the semiconductor wafer that covers the gate. A spacer is formed on each wall of the gate. Finally, a second ion implantation process is performed to form a source and a drain on the surface of the silicon substrate adjacent to the spacer.

1. Field of the Invention
The present invention relates to a method of fabricating a MOS transistor on a semiconductor wafer.
2. Description of the Prior Art
As the density of integration of semiconductor devices increases, complementary metal-oxide-semiconductor (CMOS) transistors have gradually taken the place of N-type metal-oxide-semiconductors (NMOS) in recent years. The CMOS transistor is typically composed of one PMOS transistor and one NMOS transistor. A PMOS transistor comprises a gate, a P-type source and drain (S/D) and an N-type silicon substrate.
Boron is generally used as a dopant in the prior art method to form a heavily doped drain (HDD) and an S/D region. However, owing to the small atomic volume of boron, the phenomenon of out diffusion is usually observed after using boron in an ion implantation process. Boron out diffusion effects will seriously influence the electrical properties of the MOS transistor, especially when the design line width is less than 0.18 micrometers or even less than 0.15 micrometers. In addition, using a silicon dioxide layer as an etching stop layer when forming spacers in the prior art method also results in oxide-enhanced diffusion (OED) effects during the ion implantation process. Furthermore, the silicon dioxide layer will increase the rate of boron out diffusion and decrease the boron concentration in the HDD. Consequently, there is a need to improve the manufacturing process of forming the PMOS transistor so as to enhance the quality of the semiconductor products.
Please refer to FIG. 1 to to FIG. 4 FIG. 1 to FIG. 4 are cross-sectional diagrams of the prior art method of fabricating a PMOS transistor 30 on a semiconductor wafer 10. As shown in FIG. 1, the semiconductor wafer 10 comprises a silicon substrate 12, and an N-well 11 on the surface of the silicon substrate 12 isolated by a shallow trench 14. The semiconductor wafer 10 also comprises a gate 22, which is located on the surface of the N-well 11. The gate 22 comprises a dielectric layer 20 located on the N-well 11 and a doped polysilicon layer 21 located on the dielectric layer 20. The dielectric layer 20, composed of silicon dioxide (SiO.sub.2), serves as a gate oxide layer of the PMOS transistor 30. The doped polysilicon layer 21 serves as a gate electrode of the PMOS transistor 30.
As shown in FIG. 2, a uniform liner oxide layer 16, composed of silicon dioxide (SiO.sub.2), is first formed on the surface of the semiconductor wafer 10. A P.sup.- ion implantation process is then performed to form an HDD 23 on the surface of the silicon substrate 12 adjacent to the gate 22. The dosage of boron in the P.sup.- ion implantation process is about 1.times.10.sup.14 to 5.times.10.sup.15 atoms/cm.sup.2, and the energy of the boron ions is about 10 to 15 KeV. Next, a silicon nitride layer 18 is uniformly formed on the surface of the liner oxide layer 16.
Basically, the liner oxide layer 16 is used as an etching stop layer when forming silicon nitride spacers. It also serves as a buffer layer to release thermal stress produced by the silicon nitride spacers. However, boron has a tendency to diffuse into the liner oxide layer 16. As a result, it is difficult to control the concentration of boron in the HDD 23 in the prior art method. Furthermore, during the P.sup.- ion implantation process, the liner oxide layer 16 causes a serious dosage loss problem and OED effects.
Next, as shown in FIG. 3, a conventional etching back process is used to vertically remove a portion of the silicon nitride layer 18 down to the surface of the liner oxide layer 16. The remaining portion of the liner oxide layer 16 on each wall of the gate 22 becomes a spacer 19. A heavier doping process, or a P.sup.+ ion implantation process, is then used to form an S/D 24 of the PMOS transistor 30 on the silicon substrate 12 adjacent to the gate 22. Boron, or boron fluoride ions (BF.sub.2.sup.+), with an energy of about 10 KeV and a dosage of about 2.times.10 .sup.15 to 1.times.10.sup.16 atoms/cm.sup.2 are usually used in the P.sup.+ ion implantation process. Thereafter, an annealing process at a temperature of 1000 to 1050.degree. C. is performed to diffuse the boron ions into the S/D 24 to achieve a desirable profile and to repair the damage done to the silicon substrate 12 from the ion implantation process.
Next, as shown in FIG. 4, a dry etching process is performed to etch the liner oxide layer 16 that is not covered by the spacer 19. Then, a self-aligned silicide (salicide) process is performed. A metal layer (not shown) is first formed on the surface of the semiconductor wafer 10 that covers the gate 22. A thermal process is next used to form a silicide layer 26 on top of the gate 22 and on the surface of the S/D 24. A wet etching process is next used to remove the metal layer thereby completing the PMOS transistor 30.
The liner oxide layer 16 can prevent channeling effects during the P.sup.- ion implantation process and can also prevent damage to the silicon substrate. Unfortunately, the liner oxide layer 16 also causes a serious dosage loss during the P.sup.- ion implantation process, which makes it difficult to precisely control the concentration of boron in the HDD 23. In order to overcome the problem of dosage loss, boron ions with higher energy must be used during the P.sup.- ion implantation process in the prior art method. However, these more energetic ions will result in undesirable deeper junction depths and OED effects, as well as short channel effects. In addition, out diffusion of boron into the liner oxide layer 16 also causes a decrease of the concentration of boron in the HDD 23.

Method of fabricating a MOS transistor on a semiconductor wafer


Electric discharge breakdown in an optical waveguide pattern formed on a crystal substrate having pyroelectric effect is substantially extinguished or reduced, so that the yield of optical waveguide devices in the manufacturing process can be increased. A plurality of optical waveguide patterns 5 are formed, in parallel, by means of heat treatment on a substrate 2 of lithium niobate having pyroelectric effect, and the formed waveguide patterns are cut into a predetermined chip-shape. In the manufacturing method of this optical waveguide device, patterns are formed so that both ends of the optical waveguide pattern 5 are respectively communicated at a position where both ends of the optical waveguide pattern 5 are out of an effective chip range. Further, a dummy pattern 26 is formed at a position close to a waveguide pattern 25.

Recently, in the field of information processing and transmission, attention has been given to an information processing system in which an optical communication system is used for increasing the amount of information transmitted and extending the functions of the system. Accordingly, there is a great demand for optical control devices such as optical switches and optical modulators to control optical signals. Further, there is a demand for optical control devices in which processing is carried out at high speed, the efficiency is high, the dimensions are reduced, and parts are integrated.
As examples of optical control devices used for optical communication which satisfy the demands described above, optical modulators and optical switches are known in which optical waveguide patterns are formed on a crystal substrate, and electrodes and others are arranged on these patterns. Especially, in order to enhance the efficiency and speed, attention is given to a substrate in which a crystal of lithium niobate (LiNbO.sub.3) or lithium tantalate (LiTaO.sub.3) is used because the crystal is a ferroelectric substance provided with electro-optical effect.
In the case of the optical waveguide device in which a crystal of LiNbO.sub.3 or LiTaO.sub.3 is used as the substrate, a pattern of the optical waveguide is formed in the following manner:
An optical waveguide pattern is formed on a substrate, using a metal such as titanium (Ti), by means of photolithography. When the substrate and pattern are heated to a temperature of 1000.degree. C. to 1050.degree. C., Ti metal on the substrate is thermally diffused, so that an optical waveguide pattern is formed, the width of which is usually several .mu.m to several tens of .mu.m, and the length of which is several mm to several tens of mm.
Since the above substrate, made of LiNbO.sub.3 or LiTaO.sub.3, exhibits a strong pyroelectric effect, an electric charge is generated when the temperature is changed, so that the substrate surface is electrically charged and a high potential is generated on the surface. Accordingly, a large amount of pyroelectric charge tends to accumulate on the metallic pattern (optical waveguide pattern) when the metallic pattern of Ti is heated so as to be diffused onto the substrate surface. As a result, an electric discharge is caused in a portion on the substrate, and the optical wavelength pattern is damaged.
When the rate of increase of the temperature is reduced to provide a gentle temperature change in the case where the substrate is heated, serious problems are not caused. However, in the case where the substrate is heated to a temperature from 1000.degree. C. to 1050.degree. C., taking into consideration that the productivity is enhanced, the substrate is heated, for example, at a rate of 10.degree. C./min. In this case, there is a possibility that an electric discharge is caused between the waveguide patterns by the pyroelectric effect.
In this connection, the following method can be considered. The temperature of the substrate is not quickly increased, and any generated electric charge is neutralized by ions included in the atmosphere. In this way, an excessive amount of electric charge is not accumulated on the waveguide pattern. However, this method is disadvantageous in that a complicated ion supply device is required. Therefore, this method can not be put into practical use.

Method of manufacturing an optical waveguide device


A driving method of the invention is suitable for an active matrix type liquid crystal display apparatus having row and column electrodes. The driving method includes the steps of applying a gate-one pulse for writing data for one line to the column electrodes to each of the row electrodes. The gate-on pulse has a pulse waveform which includes at least one concave portion during a horizontal period.

1. Field of the Invention
The present invention relates to a driving apparatus and method for an active matrix type liquid crystal display (LCD) apparatus having row and column electrodes in a lattice arrangement, picture element electrodes for display located in regions defined by the row and column electrodes in a matrix arrangement, and switching transistors connected to the picture element electrodes and the row and column electrodes.
2. Description of the Prior Art
FIG. 3 shows an exemplary active matrix type LCD apparatus of 4.times.4 matrix. Row electrodes (gate electrode wirings) 1-4 and column electrodes (source electrode wirings) 5 are arranged in a lattice in the row and column directions. In regions defined by the row and column electrodes, picture element electrodes 20 are arranged in a matrix. At each of the crossings of the row and column electrodes, a switching transistor 10 is provided. For the switching transistor 10, for example, a thin film transistor (TFT) is used. Gate terminals 11 of the switching transistors 10 are respectively connected to the row electrodes 1-4. Source terminals 12 of the switching transistors 10 are connected to the column electrodes 5, and drain terminals 13 thereof are connected to the corresponding picture element electrodes 20.
The column electrodes 5 are connected to a column electrode driving circuit 40. The column electrode driving circuit 40 periodically and sequentially applies data for one line to the column electrodes 5. When the switching transistors 10 are turned ON by a pulse applied from a row electrode driving circuit 30 to the row electrodes 1-4, a signal VS applied to each of the column electrodes 5 is applied to each of the picture element electrodes 20. By sequentially scanning a pulse applied from the row electrode driving circuit 30 to the row electrodes 1-4, and by varying column electrode data in synchronism with the timing, and image is displayed on the active matrix type LCD apparatus.
FIG. 4 schematically shows a configuration of the row electrode driving circuit 30. The row electrode driving circuit 30 includes a shift register 31, and four AND gates 32 respectively connected to output terminals Q1, Q2, Q3, and Q4 of the shift register 31. The shift register 31 inputs data SP at a data terminal (a terminal D) and a clock pulse CL at a clock terminal (a terminal CK), and shifts the data SP in accordance with the clock pulse CL. As a result, the shift register 31 outputs the shifted data SP to the AND gates 32 at the respective output terminals Q1, Q2, Q3, and Q4. The clock pulse CL and a LOW signal are also input into the AND gates 32. The AND gates 32 AND these input signals, and output gate-on pulses VG1-VG4 onto the row electrodes 1-4, respectively.
FIG. 5 shows waveforms of signals. Hereinafter, a waveform indicated by (N) in a figure is referred to as an Nth waveform. For example, in FIG. 5, the first to fourth waveforms shows those of the gate-on pulses VG1-VG4, the fifth waveform shows that of the clock pulse CL, the sixth waveform shows that of the data SP, and the seventh waveform shows that of the LOW signal.
Conventionally, each of the gate-on pulses VG1-VG4 applied to the row electrodes 1-4 is a one-shot pulse, as shown by the first to fourth waveforms in FIG. 5. The gate-on pulses have a waveform including an HI (high level) period and a LOW (low level) period. During the HI period, the corresponding switching transistor 10 is in an ON state, and during the LOW period, the corresponding switching transistor 10 is in an OFF state. As a result, only during the HI period of each of the gate-on pulses VG1-VG4, the signal VS shown by the eighth waveform in FIG. 5 is applied to the picture element electrodes 20 connected to the respective row electrodes 1-4 through the corresponding switching transistors 10. Accordingly, electrical charges are charged in a liquid crystal layer as a display medium of picture elements. The electrical charges are held in the liquid crystal layer during the LOW period of the gate-on pulses VG1-VG4, and each of the picture elements exhibits a transmissivity depending on the voltage applied to the picture element.
According to the conventional driving method shown in FIG. 5, in order to prevent the liquid crystals from deteriorating due to a DC voltage applied to an LCD apparatus, the polarity of the applied voltage is inverted for every line (for each of the row electrodes 1-4). In other words, a 1H inversion (the polarity is inverted every one horizontal period) system is adopted. The 1H period (one horizontal period) coincides with a period of a National Television System Committee (NTSC) television signal (1H=63.5 .mu.s).
When the gate-on pulse VG1 of the first waveform in FIG. 5 is applied to the row electrode 1 in FIG. 3, and the signal VS of the eighth waveform in FIG. 5 is applied to the column electrode 5 in FIG. 3, according to the driving method mentioned above, the potential of a picture element electrode 20 at the crossing of the row and column electrodes 1 and 5 varies. If the gate-on period is sufficiently long, the liquid crystal layer is sufficiently charged. The potential variation VLC of the picture element 20 at the crossing is saturated, as shown by the ninth waveform in FIG. 5.
In order to increase the scanning speed for improving the functionality of the LCD apparatus, it is necessary to shorten the gate-on period. However, if the gate-on period is shortened, the liquid crystal layer is insufficiently charged. This results in an insufficient voltage application to the liquid crystal layer, and causes problems in displaying an image as follows.
For example, we consider the case of the transmission type LCD apparatus of a normally white system (during no voltage application: white (light is transmitted), during voltage application: black (light is shielded)). As the scanning speed is increased, the gate-on time period is not sufficient. This causes a short of charge phenomenon in which sufficient voltage is not applied to the liquid crystal layer. As a result, there arises problems in that the resulting display is whitish and a sufficient display contrast cannot be obtained, as compared with the case where the charging is sufficiently performed by applying a voltage of the same level to a column electrode.
The above-mentioned problems are specifically shown by a ninth waveform in FIG. 6. FIG. 6 shows signal waveforms in a driving method, one horizontal scanning period is set to be one-half of the period of the NTSC television signal. The gate-on pulses VG1-VG4 respectively shown by first to fourth waveforms in FIG. 6 are applied to the row electrodes 1-4. The gate-on pulses VG1-VG4 are produced by inputting a clock pulse CL of a fifth waveform, data SP of a sixth waveform, and a LOW signal of a seventh waveform in FIG. 6 into the respective input terminals of the row electrode driving circuit 30. The signal VS shown by an eighth waveform in FIG. 6 indicates a signal to be applied to the column electrodes 5 shown in FIG. 3.
A ninth waveform VLC in FIG. 6 represents the variation in potential applied to a picture element electrode 20 at the crossing of the row electrode 1 and the column electrode 5, when the signal VS shown by the eighth waveform in FIG. 6 is applied to the column electrode 5. Since the gate-on period of the gate-on pulse of the first waveform is shorter than that of the first waveform shown in FIG. 5, the charge to the liquid crystal layer is not sufficient. As a result, the potential of VLC cannot reach a sufficient level.
The potential of VLC should reach the level indicated by a broken line of the ninth waveform in FIG. 6. However, in actuality the potential of VLC only reaches the level indicated by the solid line thereof.
For the reasons mentioned above, there arises a problem that display contrast sufficient for the display quality of the LCD apparatus cannot be obtained according to the driving method shown in FIG. 6.

Driving apparatus and method for an active matrix type liquid crystal display apparatus


External cavity optically-pumped semiconductor lasers (OPS-lasers) including an OPS-structure having a mirror-structure surmounted by a surface-emitting, semiconductor multilayer (periodic) gain-structure are disclosed. The gain-structure in pumped by light from diode-lasers. The OPS-lasers can provide fundamental laser output-power of about two Watts (2.0 w) or greater. Inactivity frequency-converted arrangements of the OPS-lasers can provide harmonic laser output-power of about one-hundred milliwatts (100 raw) or greater, even at wavelengths in the ultraviolet region of the electromagnetic spectrum. These high output powers can be provided even in single axial-mode operation. Particular features of the OPS-lasers include a heat sink-assembly for cooling the OPS-structure, a folded resonator concept for providing optimum beam size at optically-nonlinear crystals used for frequency conversion, preferred selection of optically-nonlinear materials for frequency-conversion, and compound resonator designs for amplifying second harmonic-radiation for subsequent conversion to third or fourth harmonic radiation.

The present invention relates in general to external-cavity optically-pumped semiconductor lasers (hereinafter, OPS-lasers) including a surface-emitting, semiconductor multilayer (periodic) gain-structure. The invention relates in particular to arrangements or such lasers which can provide fundamental laser output-power of about two Watts (2.0 w) or greater, and inactivity frequency-converted arrangements of such lasers which can provide harmonic laser output-power of about one-hundred milliwatts (100 mm) or greater.
The term OPS-lasers, as used herein, refers to a class of vertical-cavity surface-emitting semiconductor lasers wherein optical gain is provided by recombination of electrical carriers in very thin layers, for example, about 150 Angstrom units (A) or less, of a semiconductor material These layers are generally termed quantum-well (QW) layers or active layers.
In an OPS-laser, several QW layers, for example, about fifteen, are spaced apart by separator layers also of a semiconductor material, but having a higher conduction band energy that the QW layers. This combination of active layers and separator layers may be defined as the gain-structure of the OPS-laser. The layers of the gain-structure are epitaxially grown. On the gain-structure is an epitaxially-grown multilayer mirror-structure, often referred to as a Bragg mirror. The combination of mirror-structure and gain-structure is referred to hereinafter as an OPS-structure.
In an (external cavity) OPS-laser, another (conventional) mirror, serving as an output-coupling mirror is spaced-apart from the OPS-structure, thereby forming a resonant cavity with the mirror-structure of the aDS-structure. The resonant cavity, accordingly, includes the gain-structure of the OPS-structure. The mirror-structure and gain-structure are arranged such that QW layers of the gain-structure are spaced apart by one half-wavelength of the fundamental laser wavelength, and correspond in position with antinodes of a standing-wave of the fundamental laser-radiation in the resonator. The fundamental-wavelength is characteristic of the composition of the QW layers.
Optical pump-radiation (pump-light) is directed into the gain-structure of the OPS-structure and is absorbed by the separator layers of the gain-structure, thereby generating electrical-carriers. The electrical-carriers are trapped in the QW layers of the gain-structure and recombine. Recombination of the electrical-carriers in the QW layers yields electromagnetic radiation of the fundamental-wavelength. This radiation circulates in the resonator and is amplified by the gain-structure thereby generating laser-radiation.
OPS-lasers have often been used in the prior art as a means of conveniently testing QW structures for later use in electrically-pumped semiconductor lasers. More recently, OPS-lasers have been investigated as laser-radiation sources in their own right. The emphasis of such investigation, however, appears to be on providing a compact, even monolithic, device in keeping with the generally compact nature of semiconductor lasers and packaged arrays thereof.
The gain-structure of DES-structures may be formed from the same wide range of semiconductor-materials/substrate combination contemplated for diode-lasers. These include, but are not limited to, InGaAsP/InP InGaAs/GaAs, AlGaAS/GaAs, InGaAsP/GaAs and InGaN/Al2O3, which provide relatively-broad spectra of fundamental-wavelengths in ranges, respectively, of about 960 to 1800 nanometers (nm); 850 to 1100 nm; 700 to 850 nm; 620 to 700 nm; and 425 to 550 nm. There is, of course, some overlap in the ranges. Frequency-multiplication of these fundamental-wavelengths, to the extent that it is practical, could thus provide relatively-broad spectra of radiation ranging from the yellow-green portion of the electromagnetic spectrum well into the ultraviolet portion.
In conventional solid-state lasers, fundamental-wavelengths, and, accordingly, harmonies thereof (produced by frequency-doubling or frequency-mixing) are limited to certain fixed wavelengths characteristic of a particular dopant in a particular crystalline or glassy host, for example, the well-known 1064 nm wavelength of neodymium-doped yttrium aluminum garnet (Nd:YAG) While one of these characteristic wavelengths may be adequate for a particular application, it may not be the optimum wavelength for that application.
OPS-lasers provide a means of generating wavelengths, in a true CW mode of operation, which can closely match the optimum wavelength for many laser applications, in fields such as medicine, optical metrology, optical lithography, and precision laser machining. Prior-art OPS-lasers, however, fall far short of providing adequate power for such applications. It is believed that the highest fundamental output-power that has been reported, to date, for an OPS-laser is 700 mW at a wavelength of about 1000 nm (Kuznetsov. et al., IEEE Photonics Tech. Lett 9, 1063 (1997)). For an inactivity frequency-doubled OPS-laser, it is believed that highest output-power that has been reported is 6 mW at a wavelength of about 488 nm (Alford et al. Technical Digest of the IEEE/OSA Conference on Advanced Solid State Lasers, Boston MA, February 1-3 1999, pp 102-184). It believed that there has been no report to date of generation of continuous wave (CW) ultraviolet (UV) radiation in an OPS-laser, either directly or by frequency-multiplication.
However flexible an OPS-laser may be in potentially offering a wide selection of wavelengths, in order to be competitive in applications in which solid-state and other lasers are currently used, at least an order-of-magnitude, and preferably two orders-of-magnitude increase in power over that offered by prior-art OPS-lasers is required. This power increase must also be achieved without sacrifice of output-power stability and beam-quality. Further, in order to be applicable in the broadest range of applications the range of OPS-laser wavelengths available at high-power and with high beam-quality must be extended into the UV region of the electromagnetic spectrum, preferably to wavelengths less than 300 nm.
The present invention is directed to providing high-power OPS-lasers, including high-power OPS-lasers providing ultraviolet radiation, i.e., at wavelengths less than about 425 nm. In one particular aspect, an OPS-laser in accordance with the present invention comprises an OPS-structure having a gain-structure surmounting a mirror-structure. The gain-structure includes a plurality of active layers having pump-light-absorbing layers therebetween. The active layers have a composition selected to provide emission of electromagnetic radiation at a predetermined fundamental-wavelength between about 425 nanometers and 1800 nanometers when optical-pump light is incident on the gain-structure. The mirror-structure includes a plurality of layers of alternating high and low refractive index and having an optical thickness of about one-quarter wavelength of the predetermined wavelength.
A laser-resonator is formed between the mirror-structure of the OPS-structure and a reflector spaced apart therefrom. An optical arrangement is provided for delivering the pump-light to the gain-structure, thereby causing fundamental laser-radiation having the fundamental wavelength to oscillate in the laser-resonator. A heat-sink arrangement is provided f or cooling the OPS-structure. An optically-nonlinear crystal is located in the laser-resonator and arranged for frequency-doubling the fundamental laser-radiation, thereby providing frequency-doubled radiation having a wavelength half of the fundamental wavelength.
The laser-resonator, the optically nonlinear-crystal, the OPS-structure, the heat-sink arrangement and the optical pump-light-delivering arrangement are selected and arranged such that the resonator delivers the frequency-doubled radiation as output-radiation having a wavelength between about 212 nanometers and 900 nanometers at an output-power greater than about 100 milliwatts. The laser preferably has a resonator length greater than about 5.0 cm
In one embodiment of a high-power OPS-laser in accordance with the present invention, stable, single axial-mode, CW laser output-power of about 4.0 W at 488 nm wavelength is achieved by inactivity frequency-doubling 976 nm radiation from a single OPS-structure using an optically-nonlinear crystal of lithium triborate (LBO) in a resonator having a length of about twenty-five centimeters (cm). The OPS-structure has active layers of an In0.18Ga0.82As composition, and pump-light-absorbing (separator) layers of a GaAs0.978P0.022 composition. The laser is pumped by about 34.0 W of 808 nm radiation from two diode-laser arrays. Numerical models indicate that the same resonator may be modified by including an optically-nonlinear crystal for mixing the fundamental and frequency-doubled radiation to produce about 120.0 mW of (frequency tripled or third-harmonic) 325 nm UV radiation. A simplified configuration of the resonator of this example was used without an optically nonlinear crystal to deliver fundamental output-power of about 10 W.
The 4.0 W of frequency-doubled output-power represents over two orders-of-magnitude increase over what is believed to be the highest reported frequency-doubled output-power of any prior-art OPS-laser. It is believed that frequency-tripled output of any power has not been achieved in a prior-art OPS-laser.
Numerical models indicate that in a resonator similar to the resonator of the example above, an OPS-structure having a gain-structure InxGa1xe2x88x92xP quantum wells with InyGa1xe2x88x92yAszP1xe2x88x92z separator layers therebetween, wherein x is selected to provide fundamental radiation at 750 nm may be pumped by 12.0 Watts of pump-light at 670 nm, using a 5 mm-long LBO crystal for frequency doubling to provide output-power in excess of 1 Watt at the frequency-doubled wavelength of 375 nm.
This remarkable increase in OPS-laser output-power and the ability to generate high, CW, UV output-power, either by frequency-doubling or frequency-tripling, is achieved without sacrifice of beam-quality. Single mode operation provides that OPS-lasers in accordance with the present invention can have a beam quality less than 2.0 times, and as low as 1.2 times the diffraction limit. This high-beam quality makes the inventive OPS-lasers ideal for applications in which the output radiation must be focused to a very small spot for making precise incisions in inorganic or organic material, or must be efficiently coupled into an optical fiber for transport to a location where it is to be used.
In another aspect of an OPS-laser in accordance with the present invention, the laser includes first and second resonators arranged such that a portion of the resonator axes of each are on a coaxial path. The first resonator includes an OPS-structure arranged outside the coaxial path to provide a selected fundamental-wavelength of laser radiation. Located on the coaxial path of the first and second resonators is an optically-nonlinear crystal arranged for frequency-doubling the fundamental radiation. The first and second resonators are interferometrically matched to maintain optimum phase-matching between fundamental and frequency-doubled radiation in the optically-nonlinear crystal. Fundamental-wavelength radiation and frequency-doubled radiation circulate together only along the coaxial path. An optically-nonlinear crystal ia located in the second resonator outside the coaxial path for doubling the frequency of the frequency-doubled radiation thereby providing frequency-quadrupled radiation. Numerical models indicate that by using the 976 nm OPS-structure and pumping arrangement of the above-described first embodiment, this second embodiment is capable of providing about 2.0 W of frequency-quadrupled (244 nm) radiation.
In yet another aspect of an OPS-laser in accordance with the present invention, the laser includes first and second interferometrically-matched resonators arranged such that a portion of the resonator axes are on a coaxial path. The coaxial path includes a first optically-nonlinear crystal arranged for frequency-doubling as discussed above with respect to the second embodiment. Fundamental-wavelength radiation and frequency-doubled radiation circulate together only along the coaxial path. A second optically-nonlinear crystal is located in the coaxial path of the first and second resonators for mixing the fundamental radiation with frequency-doubled radiation thereby providing frequency-tripled radiation. Numerical models indicate that by using the 976 nm OPS-structure and pumping arrangement of the above-described first embodiment, this third embodiment is capable of providing about 4.0 W of frequency-tripled (325 nm) radiation.
Other, more general, aspects of OPS-lasers in accordance with the present invention include but are not limited to: design of heat-sink configurations and bonding methods for cooling an OPS-structure which allow the above exemplified high pump-powers to be directed on the OPS-structure while maintaining a safe operating temperature therefor; design of optically-long resonators for providing a relatively large fundamental mode-site at OPS-structure to take advantage of a larger pumped-area, thereby increasing laser output-power; design of specific, folded-resonator configurations for optimizing output of frequency-converted radiation and preventing reflection of the frequency-converted radiation back into the OPS-structure where it would be lost through absorption; selection of a specific ratio of pumped area to mode-size at the OPS to optimize use of gain, and to prevent generation to transverse modes of oscillation; use of an inactivity wavelength-selective element for preventing oscillation of fundamental radiation at wavelengths outside the spectral range of acceptance of optically nonlinear crystals; selection of optically nonlinear materials for maximum spectral acceptance to allow the use of efficient and tolerant wavelength-selective devices for the former; configuration of OPS-structures to eliminate parasitic lateral oscillation which would otherwise reduce output power; design of OPS-structures for minimum net stress and reliability under high power operation; use of radial-index gradient lens to optimize multiple optical-fiber delivery of pump-light; and design of mirror-structures for the inventive OPS-structure for maximum thermal-conductivity thereby facilitating cooling of the OPS-structures.
It will be particularly evident from the detailed description of the present invention presented below that for achieving the high powers discussed above, OPS-laser resonators in accordance with the present invention depart radically from the xe2x80x9ccompactnessxe2x80x9d philosophy of prior-art OPS-lasers and are inventively configured for inactivity frequency multiplication. It will also be evident that significant attention is directed to thermal management of OPS-structures, to the design of OPS-structures themselves, and to selection of frequency multiplication materials, in order to achieve the remarkable output-power levels, and stability of the inventive OPS-lasers. It will further be evident that certain inventive aspects of the invention are applicable to both high and low-power OPS-lasers, or even to laser types other than OPS-lasers.

High-power external-cavity optically-pumped semiconductor lasers


A filter driver may be instantiated in a smartcardreader class, and used to modify the smartcard status in an operating system.

Smartcards are portable devices that include an embedded integrated circuit. Smartcards may be passive memory devices or contain a microcontroller and associated memory for various functions. Smartcard form factors include plastic cards, fobs, subscriber identification modules (SIMs), and the like.
Applications for smartcards include payment systems, access control, identification, cryptographic controls and authentication, and telecommunications.
Following installation of necessary driver software or support applications or both, or during regular use, a smartcard may not be fully installed or recognized. This condition may require a user to physically remove and reinstall the smartcard to bring the card to full functionality within the system.

Simulation of smartcard removal and reinsertion


This unattendant data center environment protection, control and management system is able to provide means for monitoring temperature and humidity, managing power supply, and controlling access condition for a protected zone, and further, able to achieve the aim of remote control and management effect in any situation and from any distance by means of phone communication, interconnection to local network, or the internet web.

1. Field of the invention
The present invention relates to unattendant data center environment protection, control, and management system, in particular, a system which can provide means for monitoring temperature and humidity, managing power supply, and controlling entry to a protected zone. Moreover, the system of the present invention is able to achieve the aim of remote control and management effect in any situation and distance bye means of phone communication, interconnection to local network, or the internet web.
2. Description of the Prior Art
How to maintain environmental security is an important concern of people with the first priority. Most of the people rely on too much to door lock device thinking that the degree of security increases in propotion to the amount of door locks installed. In actual situation, it is regretful that even a sophisticated lock is unable to fully protect itself from being broken by an alert and skilful burgler!
The recently invented security system contributed to ensuring the environmental security a lot. However, a security system must be handled, controlled, and managed by specialized security personnel. As soon as an alarm signal informing abnormality is received, the clew who are patrolling nearest the site are dispatched there to exclude the emergency, but such a time-delayed response is by no means relevantly appreciable because it has already lost the critical time to protect the customer.
In order to solve the above described problem, the present inventor carried out theoretical studies and simulating experiments. Base on these studies and researches, the present inventor came to propose this invention.
It is an object of the present invention to provide unattendant data center environment protection, control, and management system which can provide means for monitoring temperature and humidity, managing power supply, and controlling access condition for a protected zone.
It is another object of the present invention to provide aforesaid system which is able to carry out the aforesaid missions remotely and relevantly in any situation and distance by means of phone communication, interconnection to local network, or the internet web.
To achieve these and other objects described above, the system of the present invention comprises an ECM (environment control and management) security subsystem, an ECM power switch subsystem, an ECM power sharing subsystem, and an ECM power Uninterruptible Power Supply (UPS) subsystem. By operation of these subsystems, it is able to conduct missions of monitoring temperature and humidity, managing power supply, and controlling entry to a protected zone from a control center, and to carry out the aforesaid missions remotely and relevantly in any situation and distance by means of phone communication, interconnection to local network, or the internet web.

Unattendant data center environment protection, control, and management system