An optical element includes an airtight container having opposing face walls in a thickness direction, and side walls connecting the end face walls; a first liquid sealed in the container and having polarity or conductivity; a second liquid sealed in the container and not mixed with the first liquid so as to define an interface between the first liquid and the second liquid; and voltage applying means for applying a voltage to the first liquid. Further, the first liquid and the second liquid have the same specific gravity and substantially the same refractive index, and minute particles made of a material that does not transmit light are mixed in the first liquid, such that the first liquid has less light transmittance than the second liquid. In a state in which the voltage is applied to the first liquid, the interface between the first liquid and the second liquid deforms, and a transmitting path of light is formed that passes through the end face walls and propagates in the thickness direction of the container.

1. Field of the Invention
The present invention relates to an optical element.
2. Description of the Related Art
An optical element 10 that adjusts the quantity of transmitted light by using electrocapillarity (electrowetting phenomenon) has been suggested (see JP-A-2001-228307).
As shown in FIG. 17, the optical element 10 includes an airtight container 16 that has end face walls 12 opposite to each other in a thickness direction, and side walls 14 connecting the end face walls 12, a first liquid 20 that is sealed in the container 16 and has polarity or conductivity, and a second liquid 22 that is sealed in the container 16 and has larger transmittance than the first liquid 20.
In addition, as the first liquid 20 and the second liquid 22, liquids having properties that are not mixed with each other, and liquids that have the same specific gradient are used. In a case in which only the first liquid 20 and the second liquid 22 are sealed in the container 16 without air permeating into the container 16, even though the container 16 is made to rotate or the container 16 is shaken, the initial state in which only the first liquid 20 and the second liquid 22 are sealed in the container 16 is maintained, and a state in which the interface 24 is substantially parallel to the end face wall 12 is maintained.
In FIG. 17, reference numeral 28 indicates an electrode for applying a voltage to the first liquid 20, and reference numeral 30 indicates an insulating film to cover the electrode 28.
In addition, when the voltage is applied to the first liquid 20 by a voltage applying means, by electrocapillarity, the interface 24 between the first liquid 20 and the second liquid 22 deforms, as shown by solid lines and broken lines of FIG. 17, and thus a transmitting path 18 of light that passes through the end face wall 12 and propagates in a thickness direction in the container 16 is formed.
Specifically, in a state in which a voltage is not applied, the first liquid 20 extends over the entire region in a direction orthogonal to a light transmitting direction, as shown by a solid line of FIG. 17, which results in obstructing light transmission or reducing the quantity of transmitted light. At this time, if an applied voltage is increased, as shown by broken lines in FIG. 17, the second liquid 22 comes into contact with the two end face walls 12 to form a transmitting path 18. By adjusting an applied voltage, a contact area between the second liquid 22 and one end face wall 12 is increased or decreased, and thus the size of the transmitting path 18 is adjusted.
In the optical element 10 according to the related art, it is very important to select liquids for the first liquid 20 and the second liquid 22 from various known liquids.
That is, liquids that have the same specific gravity should be selected as the first liquid 20 and the second liquid 22.
Accordingly, when an optical element 10 is manufactured, since there is a limit in kinds of used liquids, it is difficult to manufacture an optical element 10 having desired characteristic.
Accordingly, there is a need for simply manufacturing an optical element having predetermined characteristic.


A method includes determining a group to which each of a plurality of blocks belongs, the plurality of blocks being obtained by dividing each picture included in video image data; adding, to an output stream, group information expressing the group to which each of the plurality of blocks belongs; calculating an output time for each of the groups; determining output delay for each of the groups; adding, to the output stream, an output delay time from a decode time of each of the groups; controlling an encode amount so that data used for outputting all of the blocks included in one of the groups arrives at a decoding buffer of a decoding device and decoding is completed by an output time expressed by the output delay time; and performing encoding based on the encode amount that has been controlled.

Generally, video image data includes a large amount of data. Thus, a device for handling video image data compresses the video image data by encoding the video image data, when sending the video image data to another device or when storing the video image data in a storage device.
As a representative standard technology for encoding video images, MPEG (Moving Picture Experts Group phase)-2, MPEG-4, or MPEG-4 AVC/H.264 (H.264 MPEG-4 Advanced Video Coding) developed at ISO/IEC (International Standardization Organization/International Electrotechnical Commission) is widely used.
As standard encoding technologies described above, there is an inter encoding method for encoding a picture by using information of the picture that is the encoding target and information of pictures before and after the encoding target, and an intra encoding method for encoding a picture by using only information of the picture that is the encoding target.
Generally, the encoding amount of pictures or blocks that have been encoded by the inter encoding method is smaller than the encoding amount of pictures or blocks that have been encoded by the intra encoding method. Therefore, according to the selected encoding mode, the encoding amount of pictures becomes disproportionate within the same sequence. Similarly, according to the selected encoding mode, the encoding amount of blocks becomes disproportionate within the same picture.
Therefore, in order to transmit a data stream including encoded video images by a constant transmission rate even if the encoding amount varies over time, the transmission source device is provided with a transmitting buffer for a data stream, and the transmission destination device is provided with a receiving buffer for a data stream.
A delay caused by these buffers (hereinafter, "buffer delay") is the main factor causing a delay from when each picture is input in the encoding device until each picture is displayed in a decoding device (hereinafter "codec delay"). As the codec delay, there is decoding delay that is a delay relevant to decoding, and display delay that is a delay relevant to display (output).
By reducing the size of the buffer, the buffer delay and the codec delay are reduced. However, as the size of the buffer decreases, the degree in freedom in allocating the encoding amount for each picture decreases. Consequently, the image quality of a reproduced video image is deteriorated. The degree in freedom in allocating the encoding amount means the extent of variation in the encoding amount.
MPEG-2 and MPEG-4 AVC/H.264 respectively specify VBV (Video Buffering Verifier) and CPB (Coded Picture Buffer), which are operations of a receiving buffer in an ideal decoding device.
A video image encoding device controls the encoding amount so that the receiving buffer of an ideal decoding device does not overflow or underflow. An ideal decoding device is specified to perform instantaneous decoding, where the time taken for a decoding process is zero. For example, there is a technology for controlling a video image encoding device relevant to VBV (see, for example, Patent Document 1).
The video image encoding device controls the encoding amount to ensure that data of a picture to be decoded is stored in the receiving buffer at the time when the ideal decoding device decodes the picture, so that the receiving buffer of the ideal decoding device does not overflow or underflow.
The receiving buffer underflows when the video image encoding device transmits a stream by a constant transmission rate, but transmission of data used for decoding the picture is not completed until the time when the video image decoding device decodes and displays the pictures, because there is a large encoding amount for each picture. That is to say, underflow of the receiving buffer means that data used for decoding a picture is not present in the receiving buffer of the decoding device. In this case, it is not possible for the video image decoding device to perform a decoding process, and therefore frame skip occurs.
In order to perform a decoding process without causing the receiving buffer to underflow, the video image decoding device displays a picture after delaying a stream by a predetermined length of time from the receiving time.
As described above, an ideal decoding device is specified so that the decoding process is instantaneously completed by a processing time of zero. Therefore, assuming that the time of inputting an "i" th picture (hereinafter, also expressed as "P(i)") in the video image encoding device is t(i) and the time of decoding P(i) in the ideal decoding device is dt(i), it is possible to display this picture at the same time as the decode time, i.e., at dt(i).
For all pictures, the display time period of the picture {t(i+1)−t(i)} and {dt(i+1)−dt(i)} are equal, and therefore the decode time dt(i) becomes {dt(i)=t(i)+dly}, which is delayed by a fixed time dly from the input time t(i). Accordingly, the video image encoding device has to complete transmitting data used for decoding to the receiving buffer of the video image decoding device until the time dt(i).
FIG. 1 illustrates an example of the transition of the buffer occupancy amount of the receiving buffer according to the conventional technology. In the example of FIG. 1, the horizontal axis indicates the time and the vertical axis indicates the buffer occupancy amount of the receiving buffer. A line 10 indicated by a solid line indicates the buffer occupancy amount at each time point.
In the receiving buffer, the buffer occupancy amount is recovered at a predetermined transmission rate, and data used for decoding a picture at the decode time of each picture is extracted from the buffer. In the example of FIG. 1, data of P(i) starts to be input to the receiving buffer at a time at(i), and the last data of the P(i) is input at a time ft(i). The ideal decoding device completes decoding P(i) at a time dt(i), and it is possible to display P(i) at the time dt(i).
The ideal decoding device performs instantaneous decoding, while an actual video image decoding device takes a predetermined length of time to perform a decoding process. Generally, the decoding process time for one picture is shorter than the display period of a picture; however, the actual video image decoding device takes an amount of time close to the display period of a picture for performing the decoding process.
The data of P(i) is input to the receiving buffer from the time at(i) to the time ft(i). However, the time at which data used for decoding each block arrives between at(i) and ft(i) is not ensured. Therefore, the actual video image decoding device starts the process of decoding P(i) from the time ft(i). Accordingly, assuming that the maximum processing time to be taken for decoding one picture is ct, it is only possible to ensure that the actual video image decoding device completes the decoding process within the time ft(i)+ct.
The video image encoding device ensures that data used for decoding P(i) arrives at the receiving buffer until the time dt(i), i.e., it is ensured that ft(i) dt(i) is satisfied. Thus, when ft(i) is at the latest time, ft(i) becomes the same as dt(i).
In this case, the time at which completion of the decoding process of the entire P(i) is ensured is dt(i)+ct. To display all pictures at equal intervals, the video image decoding device is to delay the display times of the respective pictures by at least a time ct with respect to the ideal decoding device.
In VBV of MPEG-2 and CPB of MPEG-4 AVC/H.264, the difference between the arrival time of each encoded picture in the video image decoding device and the display time of each encoded picture that has been decoded is expressed as (ft(i)−at(i)+ct). That is to say, it is difficult to achieve a codec delay of less than the time ct, where the codec delay extends from when each picture is input to the encoding device to when the picture is output at the decoding device. That is to say, the time ct is usually the processing time for one picture, and therefore it is difficult to achieve a codec delay of less than the processing time for one picture.
Patent Document 1: Japanese Laid-Open Patent Publication No. 2003-179938
Non-patent Document 1: JCTVC-H1003, "High-Efficiency Video Coding (HEVC) text specification draft 6", Joint Collaborative Team on Video Coding of ITU-T SG16 WP3 and ISO/IEC JTC1/SC29/WG11, February 2012
Non-patent Document 2: MPEG-2 Test Model 5. April 1993.ISO-IEC/JTC1/SC29/WG11/N0400 (http://www.mpeg.org/MPEG/MSSG/tm5/)
In the conventional technology, it is difficult to make a codec delay become the processing time for one picture. However, there is the following method for making the codec delay become less than the processing time for one picture. For example, this method is for assigning each block in a picture to one of an N number of groups, and assigning a decode start time to each group. A group is, for example, one block line. A block line expresses a line of blocks in the horizontal direction of the picture.
If the amount of information generated in each group is made uniform, the difference in the decode start time of continuous groups matches the processing time for each group, and the time ct becomes the processing time ct/N of each group. Thus, as a result, it is possible to decrease the codec delay to the processing time for each group.
FIG. 2 illustrates an example where the codec delay is made to be less than one picture time by group division. A graph line 17 in FIG. 2 expresses the time transition of the buffer occupancy amount of the conventional method. Meanwhile, a graph line 15 in FIG. 2 expresses the time transition of the buffer occupancy amount according to group division.
According to the group division method, the decode start time dgt(i, n) of the "n" th group of P(i) (hereinafter, also expressed as G(i, n)) is defined, and the buffer occupancy amount is decreased. Each group is decoded by taking the group decode time ct/N indicated by the reference numeral 16 starting from the corresponding decode start time. Therefore, the delay in the display possible time (the time during which display is possible) of each group is reduced.
In the group division method, the amount of information generated in each group is substantially equal, and therefore the codec delay is reduced to the time per group. Codec delay is the maximum value in a case where the information generation amount in each block in the group is significantly disproportionate. However, under actual circumstances, the disproportion in the generated information amount in each block in the group is reduced by appropriate rate control. In this case, it is theoretically possible to further reduce the code delay, but this is difficult to achieve by the block division method. The reason for this is described with reference to FIGS. 3 through 6.
FIG. 3 illustrates operations of a receiving buffer of the video image decoding device. In the example of FIG. 3, the cumulative value of the amount of encoded data arriving at the receiving buffer, and the cumulative value of the encoded data consumed by a decoding process are used to express the operations of a receiving buffer.
A graph line 20 in FIG. 3 expresses the cumulative value of the amount of encoded data arriving at the receiving buffer. The encoded data is transmitted from the video image encoding device to the video image decoding device by a fixed rate R. In the example of FIG. 3, the first bit arrives at the receiving buffer of the video image decoding device at a time "at(0)", which is zero.
A graph line 21 in FIG. 3 expresses the cumulative value of encoded data consumed by an instantaneous decoding process in units of pictures. After the initial delay dly, the "i" th picture P(i) (i=0, . . . ) is sequentially subjected to instantaneous decoding at dt(i). The difference dt(i+1)−dt(i) in the instantaneous decode time between two continuous pictures is fixed. The encoding information amount of P(i) is expressed by b(i).
at(i) and ft(i) express the time at which the first bit in the encoded data of P(i) and the last bit in the encoded data of P(i) arrive at the video image decoding device, respectively. In order to prevent the receiving buffer of the video image decoding device from underflowing, all encoded data of P(i) is to arrive at dt(i). That is to say, dt(i)≧ft(i) and dt(i−1)≧at(i) are to be satisfied.
The capacity of the receiving buffer at each time corresponds to the difference between the graph line 20 and the graph line 21 at each time. For example, the capacity of the receiving buffer after instantaneous decoding of P(0) at time dt(0) is the bit amount indicated by a reference numeral 25.
FIG. 4 illustrates the operation of the receiving buffer focusing on one P(i). FIG. 4 is illustrated by enlarging part of FIG. 3.
Particularly, the example of FIG. 4 illustrates a case where instantaneous decoding is performed in units of pictures, the receiving buffer of the video image decoding device does not underflow, and at(i) and ft(i) are the latest times, i.e., dt(i)=ft(i) and dt(i−1)=at(i). In the example of FIG. 4, the number of groups N is 4, and the number of blocks and the generated information amount of each of the groups dgt(i, n+1)−dgt(i, n) is uniform.
A graph line 30 in FIG. 4 expresses the cumulative value of the amount of encoded data arriving at the receiving buffer of the video image decoding device. A graph line 31 expresses the cumulative value of the encoded data consumed by instantaneous decoding in units of pictures.
A graph line 32 expresses the cumulative value of the encoded data consumed by instantaneous decoding in the "n" th group G(i, n) of P(i) at dgt(i, n).
In the group division method, it is assumed that the amounts of generated information in the respective groups are averaged in the picture. That is to say, the total sum of the amounts of generated information in the blocks in the groups of P(i) is b(i)/N. b(i) is the amount of generated information in P(i).
The minimum value of the amount of generated information in the blocks in the groups of P(i) is zero, and the maximum value is b(i)/N. In a case where the blocks in P(i) are instantaneously decoded at equal intervals from dt(i−1) to dt(i), a graph line f(t) expressing the cumulative value of the consumed encoded data is present inside square areas indicated by reference numerals 35 through 38.
When the amounts of generated information in the blocks are equal, f(t) is a straight line (matching graph line 30) joining the bottom left vertex and the top right vertex of each of the square areas indicated by reference numerals 35 through 38. When a bit amount of the entire group is generated at the leading block, f(t) is a line connecting the left edge and the top edge of each of the square areas. The latter case corresponds to the maximum delay in terms of buffer delay.
In the example of FIG. 4, between the times of dt(i−1) to dt(i), the bits of the blocks in P(i) arrive at the receiving buffer. The arrival time g(x) of the "x" th bit (x=[1, b(i)]) is expressed by the following formula.
                              g                                (            x            )                          =                              dt                                      (                              i                -                1                            )                                +                                    (                                                dt                                                        (                    i                    )                                                  -                                  dt                                                        (                                          i                      -                      1                                        )                                                              )                        *                          (                              x                                  b                                                        (                    i                    )                                                              )                                                          Formula                                                  1
In view of the operations of an actual video image decoding device, a case where the blocks in P(i) are instantaneously decoded at equal intervals from dt(i−1) to dt(i) is considered. Assuming that the total number of blocks in the picture is M, the ideal instantaneous decode time p(i, m) of the "m" th block in P(i) is expressed by the following formula.
                              p                                (                          i              ,              m                        )                          =                              dt                                      (                              i                -                1                            )                                +                                    (                                                dt                                                        (                    i                    )                                                  -                                  dt                                                        (                                          i                      -                      1                                        )                                                              )                        *                          (                              m                M                            )                                                          Formula                                                  2
Depending on the shape of f(t), f(t) may be above the graph line 30. That is to say, f(p(i, m))<g(f(p(i, m))) is satisfied, and all bits used for decoding the block do not reach the receiving buffer of the video image decoding device, and underflow occurs. When the blocks have an equal number of bits, f(p(i, m))=g(f(p(i, m))) is satisfied and underflow does not occur, but this is the worst case in terms of buffer delay.
When a bit amount of the entire group is generated at the leading block, the arrival time of all bits used for decoding the leading block is delayed by dgt(i, n+1)−dtg(i, n).
In the group division method, the shape of f(t) is not known to the video image decoding device. Therefore, it is ensured that underflow is avoided even if the bit arrival delay of the leading block of G(i, n) is the maximum value dgt(i, n)−dgt(i, n−1). Thus, the instantaneous decode time of all blocks in G(i, n) are to be delayed to dgt(i, n). That is to say, the decode start time of the leading block in P(i) is dgt(i, 1). Thus, the first problem with the conventional technology is that it is not possible to further reduce the codec delay.
Furthermore, in the conventional technology, it is assumed that it is possible to instantaneously display the picture after decoding by a decode time ct/N. However, in Non-patent Document 1, an encoding method referred to as tiles is used, by which the picture is not only be divided horizontally, but may also be divided vertically. Thus, even after decoding by a decode time ct/N, there may be cases where it is not possible to instantaneously display the picture. An example where it is not possible to instantaneously display the picture is described with reference to FIG. 5.
FIG. 5 illustrates an example where instantaneous display of an image is not possible. In Non-patent Document 1, the areas of a picture, which are obtained by dividing the picture not only horizontally but also vertically, are referred to as tiles. In the example of FIG. 5, the picture is divided into four tiles.
In the order of top left, top right, bottom left, and bottom right, the tiles are referred to as tile 0 (t40), tile 1 (t41), tile 2 (t42), and tile 3 (t43), and the tiles are processed in this order.
Furthermore, inside each tile, there are several groups including plural blocks. In the example of FIG. 5, groups 0 through 3 are indicated by s41 through s44. In this case, the decoding is performed in the order of groups, which is a scan order or a decoding order as indicated by reference numerals sc41 to sc42.
Unlike the decoding order, the display order may be a raster scan depending on the display. In this case, the order is as indicated by the reference numeral sc43. In this case, even if the decoding process for the groups is completed, it is not be possible to instantaneously display the picture.
For example, immediately after decoding a group 0 (s41), the CTB in the left half of the upper stage of the picture included in the tile 0 (t40), e.g., a block b41 and a block b42, belong to the group 0 (s41) and are thus displayable. However, the CTB in the right half of the upper stage of the picture included in the tile 1 (t41), e.g., a block b45 and a block b46, belong to the group 2 (s43), are not decoded and are thus not displayable.
When the display is performed by raster scan, the structure is configured to display pictures in the order from the left edge of the screen to the right edge of the screen. Therefore, when the top stage of the picture is to be displayed, the block belonging to group 2 (s43) is to be displayed. Therefore, it is to be waited for group 2 (s43) to be decoded so that group 2 (s43) becomes displayable.
The time taken for the decoding of group 2 (s43) to be completed is the time taken to decode all blocks through which sc41 and sc42 pass in the scan order.
In the group division method, decoding may be performed quickly, but there is no consideration about the displayable time. Thus, the second problem with the conventional technology is that in order to ensure that a picture is displayed, the time for one picture is to be waited.
Furthermore, Non-patent Document 1 defines an operation when the bit amount to be used for decoding a picture is larger than the bit amount that may be accumulated in a buffer, in a case where the picture is more complex.
FIG. 6 illustrates an operation when the bit amount to be used for decoding a picture is larger than the bit amount that may be accumulated in a buffer. The video image encoding device adjusts the encoding amount so that the accumulation of rate R indicated by a predetermined rate 51 in a graph 50 in FIG. 6 does not exceed the accumulation 52 of the drawn out bit amount of the picture.
However, when the picture is complex, the bit amount accumulated in the buffer is not enough for encoding, and there are cases where underflow occurs. An example is the case of a graph 53 in FIG. 6.
When underflow occurs, as indicated by a graph 54 in FIG. 6, the decoding device does not start decoding at the original decode time dt(0) of the picture, but executes decoding at the time dt′ when bits used for decoding are received at the buffer.
Generally, the display timing of a delayed picture is the timing dt(1), which is when the next picture is supposed to be displayed. For the picture that is supposed to be displayed at the time dt(1), decoding is performed but displaying is skipped.
The third problem with the conventional technology is that Non-patent Document 1 does not clearly define the operation when underflow occurs is units of groups.

Video image encoding device, video image encoding method, video image decoding device, and video image decoding method


A computer method for redirecting input messages to an application that has at least one window redirected is provided. The method intercepts input messages, determines if the input messages are directed at the redirected application, and transforms the input messages to correspond to the actual location of the window that has been redirected before the input message is redirected to the application that has had at least one of its windows redirected.

In today's multi-tasking environments, users generally interact with computers through graphical user interfaces. Typically, these graphical user interfaces display an application's content within graphical windows on a display screen. Although multiple graphical windows can arise from a single program on a computer, the usual display screen includes windows from different programs executing independently of each other on the computer, or even several different computers.
With the development of faster computers having better graphical and multi-tasking capabilities, users may display a large number of windows on a desktop at any one time causing some windows on the display to overlap or obscure other windows. In order to view the obscured information, a user may resize or move the obstructing windows. This, however, may result in perhaps only seeing a portion of the desired information. Larger screen sizes and multiple monitors have been used to get around such a problem, but they are very expensive and can take up much desktop space. What is needed are new ways of interacting with windows in graphical user interfaces.
Typically, a user interacts with windows through various input devices, including a keyboard and a pointer device, such as a mouse. Many windowing systems provide mouse information to an application when the mouse pointer is located within an application's window boundary. Additionally, many applications rely on the mouse pointer being within its boundaries when manipulating the window by moving, resizing, selecting menu items, and the like. For example, the user may open a menu by locating the mouse pointer over a graphical menu and selecting the menu. As long as the mouse pointer remains over the menu, the menu will be visible. If the mouse pointer is moved outside of the menu's boundaries, however, the menu may disappear because the application assumes that the user is no longer interested in the menu.
Currently, there is no way of interacting with a graphical representation of a window as though the representation was a window object itself. While a user can apply transformations and effects to images on graphical displays, the user is not able to manipulate the graphical display through standard graphical user interface techniques. Accordingly, there is a need for a system and method for redirecting input so that a user may manipulate graphical images as if those images were window objects themselves.

This patent is subject to a terminal disclaimer.


There is provided a backlight unit that is capable of making it possible to highly condense light while simultaneously reducing costs. A backlight unit according to an embodiment of the present invention includes a light source for generating light; a lamp housing installed to cover the light source and for reflecting the light; and a light guide panel whereon there are formed a plurality of engraved patterns with a specific gap and a specific depth at the lower surface thereof, and wherein the vertical angle of the engraved pattern, which faces an out-coming surface of the light guide panel, is in a range of 30˜95°. Accordingly, it can be applicable to display panels of various sizes and a picture is improved at the same time. Also, in the backlight unit, it is possible to get rid of at least one of a prism sheet, a diffusion sheet and a reflecting sheet, thereby reducing costs. Moreover, this backlight unit can obtain a highly condensed light by using a light emitting diode that controls the curvature to condense the out-coming light within a specific angle.

1. Field of the Invention
The present invention relates to a backlight unit, and more particularly to a backlight unit that is capable of making it possible to highly condense light and reduces costs at the same time.
2. Description of the Background Art
Generally, a liquid crystal display LCD controls the transmittance of a light beam supplied from a backlight unit to display a desired picture on a screen by a liquid crystal display panel consisting of a plurality of liquid crystal cells arranged in matrix type form, and a plurality of control switches for switching the video signals to be supplied to each liquid crystal cell.
In conjunction with FIG. 1, there is explained a backlight unit as follows.
Referring to FIG. 1, a conventional backlight unit includes a light guide panel 4 for guiding a light beam via a light incident part 20; a reflecting plate 2 located under the light guide panel 4 for reflecting a light beam, which progresses to a lower surface and side surfaces of the light guide panel 4, to the upper surface; the first diffusion sheet 6 for diffusing the light beam passed through the light guide panel 4; the first and second prism sheet 8 and 10 for controlling the progress direction of the light beam passed through the first diffusion sheet 6; and the second diffusion sheet 12 for diffusing the light via the prism sheets 8 and 10 and protecting the prism sheets. The light incident part 20 consists of a lamp 22 for generating a light beam and a lamp housing 24 having the lamp 22 mounted on and reflecting the light beam to the light guide panel 4.
A cold cathode fluorescent lamp is mainly used as the lamp 22, and the light generated from the lamp 22 is incident on the light guide panel 4 through the incident surface located at the side surface of the light guide panel 4. The lamp housing 24 has a reflecting surface inside to reflect the light from the lamp 22 to the incident surface of the light guide panel 4. The light guide panel 4 makes it possible to deliver the light incident from the lamp 22 to where it is far away from the lamp 22. The reflecting plate 2 is installed at the lower surface of the light guide panel 4 to face it.
The reflecting plate 2 reflects again the light incident on itself through the rear surface of the light guide panel 4 to the light guide panel 4, thereby reducing light loss. A printed pattern formed at the lower surface of the light guide panel 4 is provide so that the light beam passed through the light incident part is reflected in a specific angle at the rear surface, being an inclined surface, to uniformly progress to an out-coming surface. At this moment, the light progressing to the lower surface and the side surface of the light guide panel 4 is reflected at the reflecting plate 2 to progress to the out-coming surface. The light come out via the light guide panel 4 diffuses light to the whole area.
On the other hand, the light incident on a liquid crystal display panel (not shown) has the highest light efficiency when perpendicular to the liquid crystal display panel. Therefore, it is desirable to deposit two forward directional prism sheets in order to make the progress angle of the light, which has come out of the light guide panel 4, perpendicular to the liquid crystal display panel. The light passed through the first and the second prism sheet 8 and 10 is incident on the liquid crystal display panel via the second diffusion sheet 12. The conventional backlight unit with such a composition can has a desired viewing angle profile only when it has two prism sheets. In this case, there are problems in that light loss is increased and manufacturing costs are increased as well.
There is illustrated in FIG. 2, a structure proposed to solve the problem. In conjunction with FIG. 2, it is explained as follows.
Referring to FIG. 2, a conventional backlight unit includes a light guide panel 4 for guiding a light beam via the light incident part 20, a reflecting plate 2 located at the lower part of the light guide panel 4 for reflecting a light beam progressing toward the lower and side surface of the light guide panel 4 to an upper surface thereof, a reverse directional prism sheet 14 controlling the progress direction of the light beam passed through the light guide panel 4, and a diffusion sheet 12 for diffusing a light beam passed through the reverse directional prism sheet 14.
The function and operation of the light incident part 20 and the reflecting plate 2 is explained sufficiently enough in FIG. 1 so that the detailed description will be omitted here.
A relief prism pattern provided at the lower surface of the light guide panel 4 is insufficient to satisfy a total reflection condition of the light beam passed through the light incident part 20 so that the light beam is made to progress to the upper surface uniformly. A reverse directional prism sheet 14 is arranged at the upper surface of the light guide panel 4. In this case, because the angle of the light beam coming out of the light guide panel 4 is over approximately 65°, it is desirable to keep the vertical angle of the prism sheet 14 between 63° and 70°.
Accordingly, the light beam passed through the prism sheet 14 becomes perpendicular to the liquid crystal display panel. The light beam passed through the prism sheet 14 is diffused and is progressed to the entire area by the diffusion sheet 12. The conventional backlight unit with such a composition has a problem in that the wall surface of the light guide panel 4 is mirrored or the bright line of the light incident part 20 is visible due to the use of the reverse directional prism sheet 14.
Therefore, there is an urgent need for a backlight unit that is capable of highly condensing light and minimizing the wall surface of the light guide panel 4 being mirrored and visibility of the bright line of the light incident part 20.
Such a backlight unit condenses light by use of a condensing sheet 16 with good condensing efficiency as shown in FIGS. 3 and 4.
The backlight unit for highly condensing light, shown in FIG. 3, has a relief pattern provided at the lower surface of the light guide panel 4 to provide a function of the prism sheets 10 and 8 and the diffusion sheets 6 and 12, as shown in FIG. 1. The light beam via the light guide panel 4 is passed through the condensing sheet 16 to improve its light condensing efficiency.
The backlight unit for highly condensing light, shown in FIG. 4, has a relief pattern formed at the lower surface of the light guide panel 4 and a prism foil 18 formed at the light out-coming area of the light incident part 20 for condensing the light that comes out of the lamp 22.
However, because the condensing sheet 16 shown in FIGS. 3 and 4 is so expensive that it is only used for aeronautical or military purposes. It can hardly be used for general purposes. Also, there is a problem in that the backlight unit for highly condensing light, shown in FIG. 4, has a size as large as the area where the prism foil 18 is formed.


A hydrocarbon synthesis catalyst is formed by contacting the catalyst precursor with a reducing gas comprising a mixture of hydrogen reducing gas and ammonia, at elevated temperature and pressure effective for conventional hydrocarbon synthesis catalyst formation by reduction in hydrogen.

1. Field of the Invention
The invention relates to activating a hydrocarbon synthesis catalyst with hydrogen and ammonia. More particularly, the invention relates to forming an active hydrocarbon synthesis catalyst, including a Fischer-Tropsch type of hydrocarbon synthesis catalyst, by contacting a hydrocarbon synthesis catalyst precursor, comprising at least one catalytic metal component, with a reducing gas comprising a mixture of hydrogen and ammonia, at conditions effective to reduce the precursor and form an activated catalyst, and to a hydrocarbon synthesis process using the catalyst.
2. Background of the Disclosure
The synthesis of hydrocarbons, including oxygenated hydrocarbons such as methanol, from a synthesis gas comprising a mixture of H2 and CO is well known. The synthesis gas feed is contacted with a Fischer-Tropsch catalyst at conditions effective for the H2 and CO in the feed gas to react and form hydrocarbons. The synthesis is known as a Fischer-Tropsch hydrocarbon synthesis. Depending on the catalyst and conditions, the hydrocarbons may range from oxygenated compounds such as methanol and higher molecular weight alcohols, to high molecular weight paraffins which are waxy solids at room temperature. The process also makes, in lesser amounts, alkenes, aromatics, organic acids, ketones, aldehydes and esters. The synthesis is conducted in a fixed or fluidized catalyst bed reactor or in a liquid phase slurry reactor. Hydrocarbon synthesis catalysts are also well known and typically include a composite of at least one iron group catalytic metal component supported on, or composited with, with at least one inorganic refractory metal oxide support material, such as alumina, amorphous, silica-alumina, zeolites and the like. Various catalyst preparation methods have been used to form hydrocarbon synthesis catalysts, including impregnation, incipient wetness, compositing, ion exchange and other known techniques, to form a catalyst precursor. The precursor must be activated to form the catalyst. Typical activation methods include oxidation or calcination, followed by reduction in flowing hydrogen, multiple oxidation-reduction cycles and also reduction without prior oxidation. Examples of catalyst preparation and activation methods for Fischer-Tropsch hydrocarbon synthesis catalysts are disclosed in, for example, U.S. Pat. Nos. 4,086,262; 4,492,774 and 5,545,674.
The invention relates to forming an active hydrocarbon synthesis catalyst, including a Fischer-Tropsch type of hydrocarbon synthesis catalyst, by contacting a hydrocarbon synthesis catalyst precursor, comprising at least one catalytic metal component, with a reducing gas comprising a mixture of hydrogen and ammonia, at conditions of temperature and pressure effective to reduce the precursor and form an active catalyst, and to a hydrocarbon synthesis process using the activated catalyst. It has been found that forming the hydrocarbon synthesis catalyst by reducing the precursor, with a reducing gas comprising a mixture of hydrogen and ammonia, improves the properties of the resulting activated catalyst with respect to at least one of increased C5+ selectivity, increased alpha (Schultz-Flory alpha) of the synthesis reaction and a reduction in methane make. These benefits are unexpected, in view of the fact that ammonia is a well known hydrocarbon synthesis catalyst poison. The catalyst precursor preferably comprises at least one catalytic metal component and at least one metal oxide catalyst support component.
The catalyst precursor may or may not be calcined prior to the reduction in the mixture of hydrogen and ammonia. The mixture of hydrogen and ammonia reducing gas may be substantialy comprised of hydrogen and ammonia or it may contain one or more diluent gasses which do not adversely effect or interfere with the activation, such as methane or argon and the like. The amount of ammonia present in the reducing gas will broadly range from 0.01 to 15 mole %, preferably 0.01 to 10 mole %, more preferably from 0.1 to 10 mole % and still more preferably from 0.5 to 7 mole %, based on the total gas composition. The hydrogen to ammonia mole ratio in the gas will range from 1000:1 to 5:1 and preferably from 200:1 to 10:1.
Thus, in one embodiment the invention is a process which comprises contacting a Fischer-Tropsch type of hydrocarbon synthesis catalyst precursor, comprising at least one catalytic metal component, and preferably at least one catalytic metal component and a metal oxide support type of component, with a reducing gas comprising a mixture of hydrogen and ammonia, at conditions effective to reduce the precursor and form an active catalyst. In another embodiment, the invention comprises a process for synthesizing hydrocarbons from a synthesis gas which comprises a mixture of H2 and CO, wherein the synthesis gas contacts with a Fischer-Tropsch type of hydrocarbon synthesis catalyst, at reaction conditions effective for the H2 and CO in the gas to react and form hydrocarbons and wherein the catalyst comprises a composite of at least one catalytic metal component and preferably also a metal oxide support component, and has been formed by contacting a catalyst precursor with a reducing gas comprising a mixture of hydrogen and ammonia, at conditions effective to reduce the precursor and form the catalyst. In a still further embodiment, at least a portion of the synthesized hydrocarbons are liquid at the synthesis reaction conditions. The conditions of temperature and pressure required to reduce the precursor and form a catalyst with a reducing gas comprising a mixture of hydrogen and ammonia in the practice of the invention, are the same conditions used for conventional hydrocarbon synthesis catalyst reduction and activation with hydrogen, in the absence of ammonia.
Hydrocarbon synthesis catalysts are well known and a typical Fischer-Tropsch hydrocarbon synthesis catalyst will comprise, for example, catalytically effective amounts of one or more Group VIII metal catalytic components such as Fe, Ni, Co and Ru. Preferably the catalyst comprises a supported catalyst, wherein the one or more support components of the catalyst will comprise an inorganic refractory metal oxide. The metal oxide support component is preferably one which is difficult to reduce, such an oxide of one or more metals of Groups III, IV, V, VI, and VII. The metal Groups referred to herein are those found in the Sargent-Welch Periodic Table of the Elements, (copyright) 1968. Typical support components include one or more of alumina, silica, and amorphous and crystalline aluminosilicates, such as zeolites. Particularly preferred support components are the Group IVB metal oxides, especially those having a surface area of 100 m2/g or less and even 70 m2/g or less. These support components may, in turn, be supported on one or more support materials. Titania, and particularly rutile titania, is a preferred support component, especially when the catalyst contains a cobalt catalytic component. Titania is a useful component, particularly when employing a slurry hydrocarbon synthesis process, in which higher molecular weight, primarily paraffinic liquid hydrocarbon products are desired. In some cases in which the catalyst comprises catalytically effective amounts of Co, it will also comprise one or more components or compounds of Re, Ru, Fe, Ni, Th, Zr, Hf, U, Mg and La, some of which are effective as promoters. A combination of Co and Ru is often preferred. Useful catalysts and their preparation are known and illustrative, but nonlimiting examples may be found, for example, in U.S. Pat. Nos. 4,568,663; 4,663,305; 4,542,122; 4,621,072 and 5,545,674.
The catalyst precursor is prepared by any convenient and known method, such as impregnation, incipient wetness, ion exchange, kneading, precipitation or coprecipitation, melt deposition or any other known compositing techniques. The catalytic metal component is typically applied as a solution of a compound of the metal that decomposes during the subsequent reduction or calcination, followed by reduction with the hydrogen and ammonia mixture according to the practice of the invention. For example, a cobalt component is typically applied to a support component as a nitrate salt. It is not uncommon to calcine the precursor after each application of reducible catalytic metal compound. After forming and extruding the precursor composite, it is typically pilled and dried. The precursor is then reduced or calcined and reduced, to form the catalyst. In the prior art, the reduction is achieved by contacting the precursor with flowing hydrogen or a hydrogen reducing gas, at conditions effective to reduce the catalytically active metal component (e.g., cobalt) to the metal form. A common method is known as the R-O-R method, in which the precursor is reduced in hydrogen, then calcined, followed by reducing again. In the prior art methods, the reducing hydrogen gas can be neat (all hydrogen), or mixed with one or more diluent gasses (e.g., methane, argon) which are inert towards the reduction. In the practice of the invention, the R-O-R method may also be used and a conventional hydrogen reducing gas employed for the first reduction, prior to calcination. However, in the practice of the invention, the second and final reduction, which is applied after the calcination, is achieved using a reducing gas comprising a mixture of hydrogen and ammonia. Typical reducing conditions effective for forming the catalyst comprising the reduced metal component on the support from the precursor, range from xc2xd to 24 hours, 200-500xc2x0 C, 1-100 bar, and a GHSV of 50-10000. The actual conditions will depend on the hydrogen concentration in the reducing gas, as well as the metal to be reduced and its precursor form (e.g., salt or oxide). In the catalyst forming and activation process of the invention, the catalyst precursor which may or may not have been calcined, is contacted with a reducing gas comprising a mixture of hydrogen and ammonia, at typical reducing conditions, as set forth above, similar to those used for normal reduction. The precursor may be merely the dried composite without calcining, a calcined composite, or a composite in which multiple catalytic metal salt depositions have been made onto the support, with or without calcining after each deposition. In the case of the R-O-R procedure, the catalyst of the invention is formed if during the second, or final reduction, the reducing gas comprises the hydrogen and ammonia mixture. Catalyst activation may be conducted according to the process of the invention, either prior to loading it into the hydrocarbon synthesis reactor or in-situ in the hydrocarbon synthesis reactor.
The catalyst formed according to the process of the invention may be used in either a fixed bed, fluid bed or slurry hydrocarbon synthesis processes, for forming hydrocarbons from a synthesis gas comprising a mixture of H2 and CO. These processes are well known and documented in the literature. In all of these processes, the synthesis gas is contacted with a suitable Fischer-Tropsch type of hydrocarbon synthesis catalyst, at reaction conditions effective for the H2 and CO in the gas to react and form hydrocarbons. Depending on the process, the catalyst and synthesis reaction variables, some of these hydrocarbons will be liquid, some solid (e.g., wax) and some gas at standard room temperature conditions of temperature and pressure of 25xc2x0 C. and one atmosphere, particularly if a catalyst having a catalytic cobalt component is used. In a fluidized bed hydrocarbon synthesis process, all of the products are vapor or gas at the reaction conditions. In fixed bed and slurry processes, the reaction products will comprise hydrocarbons which are both liquid and vapor at the reaction conditions. Slurry hydrocarbon synthesis processes are sometimes preferred, because of their superior heat (and mass) transfer characteristics for the strongly exothermic synthesis reaction and because they are able to produce relatively high molecular weight, paraffinic hydrocarbons when using a cobalt catalyst. In a slurry hydrocarbon synthesis process, a synthesis gas comprising a mixture of H2 and CO is bubbled up as a third phase through a slurry in a reactor which comprises a particulate Fischer-Tropsch type hydrocarbon synthesis catalyst dispersed and suspended in a slurry liquid comprising hydrocarbon products of the synthesis reaction which are liquid at the reaction conditions. The mole ratio of the hydrogen to the carbon monoxide in the synthesis gas may broadly range from about 0.5 to 4, but is more typically within the range of from about 0.7 to 2.75 and preferably from about 0.7 to 2.5. The stoichiometric mole ratio for a Fischer-Tropsch hydrocarbon synthesis reaction is 2.0, but it can be increased to obtain the amount of hydrogen desired from the synthesis gas for other than the hydrocarbon synthesis reaction. In a slurry hydrocarbon synthesis process, the mole ratio of the H2 to CO is typically about 2.1/1. Reaction conditions effective for the various hydrocarbon synthesis processes will vary somewhat, depending on the type of process, catalyst composition and desired products. Typical conditions effective to form hydrocarbons comprising mostly C5+ paraffins, (e.g., C5+-C200) and preferably C10+ paraffins, in a slurry process employing a catalyst comprising a supported cobalt component include, for example, temperatures, pressures and hourly gas space velocities in the range of from about 320-600xc2x0 F., 80-600 psi and 100-40,000 V/hr/V, expressed as standard volumes of the gaseous CO and H2 mixture (0xc2x0 C., 1 atm) per hour per volume of catalyst, respectively. These conditions nominally apply to the other processes as well.
Hydrocarbons produced by a hydrocarbon synthesis process according to the practice of the invention are typically upgraded to more valuable products, by subjecting all or a portion of the C5+ hydrocarbons to fractionation and/or conversion. By conversion is meant one or more operations in which the molecular structure of at least a portion of the hydrocarbon is changed and includes both noncatalytic processing (e.g., steam cracking), and catalytic processing (e.g., catalytic cracking) in which a fraction is contacted with a suitable catalyst. If hydrogen is present as a reactant, such process steps are typically referred to as hydroconversion and include, for example, hydroisomerization, hydrocracking, hydrodewaxing, hydrorefining and the more severe hydrorefining referred to as hydrotreating, all conducted at conditions well known in the literature for hydroconversion of hydrocarbon feeds, including hydrocarbon feeds rich in paraffins. Illustrative, but nonlimiting examples of more valuable products formed by conversion include one or more of a synthetic crude oil, liquid fuel, olefins, solvents, lubricating, industrial or medicinal oil, waxy hydrocarbons, nitrogen and oxygen containing compounds, and the like. Liquid fuel includes one or more of motor gasoline, diesel fuel, jet fuel, and kerosene, while lubricating oil includes, for example, automotive, jet, turbine and metal working oils. Industrial oil includes well drilling fluids, agricultural oils, heat transfer fluids and the like.

Activation of hydrocarbon synthesis catalysts with hydrogen and ammonia

ExxonMobil Research and Engineering Company


A wiper device for a vehicle which, when abnormal load is applied, absorbs the abnormal load so that wiping operation by a wiper blade can be carried out continuously. The wiper device is compact, and dimensional management thereof is easy. One end of a first crank lever forming a portion of a crank arm is attached to an output shaft, whereas a cylindrical portion is fixed by caulking to another end of the first crank lever by a pin. An annular portion is formed at one end of a second crank lever. An elastic rubber bush is interposed between the cylindrical portion and the annular portion. The first crank lever and the second crank lever are supported by the elastic rubber bush so as to be freely rotatable.

1. Field of the Invention
The present invention relates to a wiper device for a vehicle which absorbs an abnormal load applied thereto.
2. Description of the Prior Art
Conventionally, in wiper devices for vehicles, there is a drawback in that when the wiper device is operated with, for example, snow having accumulated on the wiper wiping range, the wiper blades collide against the accumulated snow such that the wiping operation is hampered. Therefore, abnormal load is generated at the wiper blades, and the operation of the entire wiper device stops.
In order to overcome this drawback, Japanese Utility Model No. 5-56694 discloses a wiper device for a vehicle which absorbs abnormal load such that continuous operation is possible.
As illustrated in FIGS. 10 and 11, in this wiper device, a first link rod 113 and a first pivot lever 114 are connected via a segment lever 115. The segment lever 115 is formed by a first connecting portion 121, which is supported so as to rotate freely with the first pivot lever 114, and a second connecting portion 122, which is set apart from the first connecting portion 121. The second connecting portion 122 is fixed by a second connecting pin 114c at whose outer periphery a buffer member 110 is disposed. In accordance with this wiper device, when abnormal load is applied, the segment lever 115 rotates around the first connecting portion 121 a predetermined angle with respect to the first pivot lever 114. The buffer member 110 compressively deforms in the radial direction in accordance with the rotation of the segment lever 115, so that the abnormal load can be absorbed.
However, in this disclosed art, the first pivot lever 114 and the segment lever 115 are attached at the first connecting portion 121 so as to be freely rotatable. A drawback arises in that, because there is joggling between the first connecting portion 121 and the segment lever 115, the dimensions of the first connecting portion 121 and the segment lever 115 must be strictly managed during manufacturing.
The rotational angle of the segment lever 115 is determined by the outer diameter dimension of the buffer member 110. Therefore, a drawback arises in that, in order to handle abnormal loads of wiper devices having large wiping angles, the outer diameter of the buffer member 110 must be made large, which leads to an increase in the size of the wiper device.
Other art related to the present invention are disclosed in U.S. Pat. No. 4,765,018; DE 3734309A1; DE 2820104A1; and FR 2557051.

Wiper device with elastic bush for absorbing excess load


The present disclosure provides an organic light emitting diode (OLED) substrate and a manufacturing method thereof, and a display device. The OLED substrate includes: a base substrate; a pixel defining layer on the base substrate, the pixel defining layer including pixel defining patterns for defining sub-pixel units, each sub-pixel unit being defined between adjacent two of the pixel defining patterns; and an organic light emitting layer on a side of the pixel defining layer away from the base substrate, the organic light emitting layer including a first portion in each sub-pixel unit and a second portion on each pixel defining pattern. Each pixel defining pattern is provided with a groove structure therein, and part of the second portion of the organic light emitting layer in the groove structure and the other part of the second portion of the organic light emitting layer are spaced apart from each other.

Organic light emitting diodes (OLEDs) have unique characteristics of self-luminescence, fast response, rich color, wide viewing angle, and capability of being fabricated on flexible substrates, and displays based on OLEDs are becoming the mainstream in the display field.
A pixel defining layer is typically fabricated on an OLED substrate to define and separate individual sub-pixel units, and the OLED substrate typically includes organic light emitting devices, whose functional layers and cathodes typically cover the entire surface of the OLED substrate.

Organic light emitting diode (OLED) substrate and manufacturing method thereof, display device

BEIJING BOE TECHNOLOGY DEVELOPMENT CO., LTD.


In a computer graphics system, an address generator processes physical and virtual addresses using a common command set. The address generator formulates addresses as a function of distance from the origin of the desired destination area in a destination memory to the requested position in the destination area. A plurality of context drawing commands is used to define a desired context in which drawing graphics commands operate. Different parts of the context are changeable/redefinable independently of the other parts. Graphics commands have a format of multiple fields having corresponding parameters arranged in order of common use of the parameter such that fields of less commonly used parameters are at an omittable end of the format. Raster drawing commands are delimited by a beginning and end indicator to form a drawing unit. For clip list processing, a drawing unit is stored as a single occurrence in the system command buffer.

A typical computer graphics system employs a memory source of data to be displayed, an address generator, a graphics controller, and a video display unit (e.g., CRT and the like). Graphics commands are transmitted from a host processor and are written to a register interface. Operands of the graphics commands are stored on the graphics controller. Common variations of this include:
(1) the graphics controller reads graphics commands only from main memory via physical dma;
(2) the graphics controller reads graphics commands from physical main memory and can move operands between graphics controller memory and main physical memory. However, graphics operations cannot occur until the data is in graphics controller memory.
The stored operands include source addresses (i.e., main memory addresses) of data to be displayed and so-called destination addresses (i.e., memory locations in a frame buffer that supports the video display). Under the control of timing signals, the address generator provides appropriate pairs or sequences of operand addresses while the graphics controller sequentially operates on respective data to generate desired screen views on the video display unit. In particular, the graphics controller reads memory data into the frame buffer with respective source data being placed at respective destination addresses in the frame buffer. Thereafter the graphics controller provides a display of data to the display unit by enabling sequential reading of the contents of the frame buffer. That is, the frame buffer supports raster scanning from a first line through succeeding lines of the screen view on the display unit such that the screen view is continuously refreshed.
Existing problems or disadvantages of computer graphics systems of the prior art include:
Lack of direct access of virtual memory and lack of write access to main memory; PA1 The address generator can only draw to its own memory, i.e., the frame buffer or a graphics-private memory. This is a cost disadvantage, and in the case of large operands can be a performance disadvantage; PA1 The application/program (client) requesting execution of a graphics command is required to provide physical addresses if the graphics controller has the capacity to access main physical memory. Furthermore, if a graphics operation spans virtual pages, the client program must segment and translate virtual memory boundaries for each graphics operation so they don't span physical pages; PA1 High overhead for context setup, i.e., setup commands, to support a series of graphics operations and clip list processing commands. PA1 a computer graphics system that uses virtual main memory for offscreen operands. This eliminates the cost of maintaining graphics-private memory, eliminates overhead of moving operands in and out of graphics controller memory and simplifies the programming model; PA1 a computer graphics system that implements various other functions in main memory which are typically implemented with graphics-private memory; PA1 a computer graphics system that provides an efficient programming interface and serves as an independent graphics coprocessor that involves minimal to no CPU processing.

Address method for computer graphics system


An authentication method and system in a communication system are provided. An MS, a BS and an AAA server acquire a first MSK by a first EAP authentication for the MS in an EAP-in-EAP scheme. After the first EAP authentication, they acquire a second MSK by a second EAP authentication for the MS in the EAP-in-EAP scheme.

1. Field of the Invention
The present invention relates generally to a communication system, and in particular, to an authentication system and a method thereof in a communication system.
2. Description of the Related Art
Communication systems are being developed to provide users with service having various levels of Quality of Service (QoS). There are ongoing studies for supporting high-speed service by ensuring mobility and QoS in a Broadband Wireless Access (BWA) communication system such as Wireless Local Area Network (WLAN) and Wireless Metropolitan Area Network (WMAN). Institute of Electrical and Electronics Engineers (IEEE) 802.16a/d and IEEE 802.16e are such major systems.
With reference to FIG. 1, authentication, particularly by the twice Extensible Authentication Protocol (EAP) in a typical IEEE 802.16e communication system will be described herein. For notational simplicity, the twice EAP is called 'EAP-in-EAP' and an operation mode by EAP-in-EAP is called 'EAP-in-EAP mode'.
FIG. 1 is a diagram illustrating a signal flow for EAP-in-EAP authentication in a typical IEEE 802.16e communication system.
Referring to FIG. 1, the IEEE 802.16e communication system includes a Mobile Station (MS) 100, a Base Station (BS) 140, and an Authorization, Authentication, and Accounting (AAA) server 180. Since the IEEE 802.16e communication system operates in EAP-in-EAP, it authenticates in the twice EAP scheme. For convenience sake, authentication based on the EAP scheme is referred to as 'EAP authentication'. The first of the two EAP authentications is device authentication 120 and the second is user authentication 160 after the first EAP authentication is successful.
When device authentication is required, the BS 140 transmits an EAP-REQUEST/IDENTITY message to the MS 100, requesting EAP authentication. Because EAP messages are exchanged between the MS 100 and the BS 140 by Privacy Key Management (PKM)_EAP_TRANSFER in the IEEE 802.16e system, the BS 140 transmits a PKM_EAP/EAP-REQUEST/IDENTITY message to the MS 100 in step 101. The MS 100 replies by transmitting a PKM_EAP/EAP-RESPONSE/IDENTITY message in step 103.
The BS 140 forwards the PKM_EAP-EAP-RESPONSE/IDENTITY message to the AAA server 180. EAP messages are exchanged between the BS 140 and the AAA server 180 by Remote Authentication Dial-In User Service (RADIUS) protocol messages or DIAMETER protocol messages. In the illustrated case of FIG. 1, RADIUS protocol messages are used between the BS 140 and the AAA server 180. Hence, the BS 140 transmits a RADIUS ACCESS REQUEST/IDENTITY message to the AAA server 180 in step 105.
The AAA server 180 performs device authentication on the MS 100 by authenticating the PKM_EAP messages using EAP-Transport Level Security (TLS), EAP-Transport Level Security Pre-Shared Key (TLSPSK), EAP-Authentication and Key Agreement (AKA), or EAP-PSK in step 107. As a consequence of the device authentication, the AAA server 180 and the MS 100 share a Master Session Key (MSK) in steps 109 and 111.
The AAA server 180 transmits a RADIUS ACCEPT message as an EAP-SUCCESS message to the BS 140 in step 113. The RADIUS ACCEPT message includes the MSK. In step 115, the BS 140 transmit a PKM_EAP/EAP-SUCCESS message to the MS 100, notifying of the success of the EAP authentication.
In steps 117 and 119, the MS 100 and the BS 140 generate an EAP Integrity Key (EIK) and a Pairwise Master Key (PMK) from the MSK during the device authentication 120. The EIK generated created through the device authentication 120 is used to protect EAP messages transmitted during the second EAP authentication, i.e. the user authentication 160.
During the user authentication 160, the BS 140 transmits a PKM_EAP/EAP-REQUEST/IDENTITY message to the MS 100 when the user authentication is needed, in step 161. The MS 100 replies by transmitting a PKM_EAP/EAP-RESPONSE/IDENTITY message in step 163.
In step 165, the BS 140 converts the PKM_EAP/EAP-RESPONSE/IDENTITY message in the form of a RADIUS ACCESS REQUEST/IDENTITY message and transmits it to the AAA server 180.
The AAA server 180 performs user authentication on the MS 100 by authenticating the PKM_EAP messages using EAP-Message-DigestS (MD5) or EAP-Microsoft Challenge Authentication Protocol version 2 (MSCHAPv2) in step 167. Unlike the device authentication 120, no additional MSK is generated even when the user authentication is completed. Meanwhile, upon reception of a RADIUS ACCEPT message in step 169, the BS 140 transmits a PKM_EAP/EAP-SUCCESS message to the MS 100 in step 171. In steps 173 and 175, the MS 100 and the BS 140 generate an Authorization Key (AK) using the PMK. The creation of the AK will be described later in more detail with reference to FIG. 2.
As described above, in EAP-in-EAP authentication of the IEEE 802.16e communication system, an MSK is generated during the first EAP authentication only.
FIG. 2 is a flowchart illustrating a creation procedure for an AK in the typical IEEE 802.16e communication system. This operation takes place in the MS and the BS each and the creation of the AK will be described herein in the context of the BS.
Referring to FIG. 2, the BS receives an MSK generated during the first EAP authentication, i.e. the device authentication from the AAA server in step 211 and generates an EIK and a PMK using the MSK in step 213. Specifically, the BS generates an EIK and a PMK with a predetermined number of bits, for example, a 160-bit EIK and a 160-bit PMK by truncating the MSK.
In step 215, the BS generates an AK by applying the PMK to a predetermined function. Specifically, the BS uses the PMK in a Dot16KDF function, for example. The Dot16KDF function is expressed set forth in Equation (1) below asAK=Dot16KDF(PMK, SSID|BSID|'AK',160)   (1)where SSID is the Identifier (ID) of the MS for which the EAP authentication is performed, BSID is the ID of the BS, 'AK' is the AK created by the Dot16KDF, and 160 denotes the length of the AK, 160 bits. Hence, the Dot16KDF function generates a 160-bit AK using the PMK and a parameter of the SSID and the BSID in concatenation.
FIG. 3 is a diagram illustrating a signal flow for a Security Association & Traffic Encryption Key (SA-TEK) 3way handshake procedure for EAP-in-EAP authentication in the typical IEEE 802.16e communication system.
Referring to FIG. 3, the IEEE 802.16e communication system includes an MS 300, an adversary MS (ADV) 320, a BS 340, and an AAA server 360. The MS 300 and the BS 340 are normal devices/users, and the ADV 320 is an adversary device/user which has a valid key for the first EAP authentication and intercepts an EAP message from the MS 300 during the second EAP authentication.
The first EAP authentication is performed among the MS 300, the BS 340, and the AAA server 360 in the manner illustrated with reference to FIG. 1 in step 311. In steps 313 and 315, thus, the MS 300 and the BS 340 acquire an EIK (EIKMS) and a PMK (PMKMS).
Meanwhile, the ADV 320 also performs the EAP authentication with the BS 340 and the AAA server 360 in step 317. In steps 319 and 321, thus, the ADV 320 and the BS 340 acquire an EIK (EIKADV) and a PMK (PMKADV).
When user authentication is needed, the BS 340 then transmits a PKM_EAP/EAP-REQUEST/IDENTITY message to both the MS 300 and the ADV 320 in steps 323 and 325. The MS 300 replies by transmitting a PKM_EAP/EAP-RESPONSE/IDENTITY message in step 327. The ADV 320 monitors the PKM_EAP/EAP-RESPONSE/IDENTITY message, copies it, and transmits the copy using EIKADV in step 329.
Upon reception of the PKM_EAP/EAP-RESPONSE/IDENTITY messages from the MS 300 and the ADV 320, the BS 340 converts the PKM_EAP/EAP-RESPONSE/IDENTITY messages in the form of RADIUS REQUEST/IDENTITY messages and forwards them to the AAA server 360 in steps 331 and 333.
The AAA server 360 transmits ACCESS CHALLENGE messages to the MS 300 and the ADV 320 in steps 335 and 337. The ACCESS CHALLENGE messages each include authentication parameters for access attempt, CHALLENGE AND SECRETE.
The MS 300 generates a parameter VALUE using CHALLENGE and SECRETE included in the ACCESS CHALLENGE message. VALUE is created by a predetermined function, for example, an MD5 function expressed as set forth below in Equation (2):VALUE=MD5(ID, SECRET, CHALLENGE)   (2)where ID represents the ID of the MS 300.
In step 341, the MS 300 transmits a PKM_EAP/EAP-RESPONSE/RESPONSE message including its ID and VALUE to the BS 340. However, the ADV 320 intercepts the PKM_EAP/EAP-RESPONSE/RESPONSE message and transmits a PKM_EAP/EAP-RESPONSE/RESPONSE message including the ID of the ADV 320 and VALUE created by the MS 300 using EIKADV to the BS 340 in step 343.
The BS 340 then converts the PKM_EAP/EAP-RESPONSE/RESPONSE message received from the ADV 320 in the form of a RADIUS ACCESS REQUEST/RESPONSE message and forwards it to the AAA server 360 in step 345.
The AAA server 360 authenticates the ADV 320 using an ID, SECRET, and VALUE that it has in step 347. As the authentication is successful, the AAA server 360 transmits a RADIUS ACCEPT message notifying of the successful EAP authentication to the BS 340 in step 349. In step 351, thus, the ADV 320 succeeds in the EAP authentication when the SA-TEK 3-way handshake is performed among the ADV 320, the BS 340 and the AAA server 360. The phenomenon of the adversary device/user intercepting the AK of the normal device/user and performing EAP authentication is called Man-in-the-middle-attack.
As described above, because in EAP-in-EAP authentication, the typical IEEE 802.16e communication system generates an MSK during the first EAP authentication only and an AK is created using a PMK derived from the MSK, the man-in-the-middle-attack phenomenon takes place. As a result, a normal service is impossible to provide to a normal device/users, thereby decreasing the overall QoS of the system. Accordingly, there is a need for developing a new authentication method for eliminating the man-in-the-middle-attack phenomenon.

Authentication system and method thereof in a communication system


An apparatus, method and system is described herein for dynamic power control of a power domain. A power limit over a time window is provided. And over a control loop period a power interface determines energy consumption of the power domain, intelligently budgets power among devices within the power domain based on the energy consumption, converts those budgets to performance maximums for the power domain, and limits performance of devices in the power domain to the performance maximums utilizing a running average power limit.

Advances in semi-conductor processing and logic design have permitted an increase in the amount of logic that may be present on integrated circuit devices. As a result, computer system configurations have evolved from a single or multiple integrated circuits in a system to multiple hardware threads, multiple cores, multiple devices, and/or complete systems on individual integrated circuits. Additionally, as the density of integrated circuits has grown, the power requirements for computing systems (from embedded systems to servers) have also escalated. Furthermore, software inefficiencies, and its requirements of hardware, have also caused an increase in computing device energy consumption. In fact, some studies indicate that computers consume a substantial amount of the entire electricity supply for the United States of America.
As a result, there is a vital need for energy efficiency and conservation associated with integrated circuits. And as servers, desktop computers, notebooks, ultrabooks, tablets, mobile phones, processors, embedded systems, etc. become even more prevalent (from inclusion in the typical computer, automobiles, and televisions to biotechnology), the effect of computing device sales stretches well outside the realm of energy consumption into a substantial, direct effect on The United States economy, as computing device related sales already have a large causal relationship with The United States Gross Domestic Product. Moreover, computer sales internationally have drastically increased; especially in emerging markets.
When power consumption becomes more of a factor, the trend towards always increasing performance is now being counterbalanced with power consumption concerns. For example, some power capping technologies, such as those utilized in data centers, ensure power doesn't exceed a limit. However, within platforms or single integrated circuits, power consumption and regulation has predominately been decentralized and uncoordinated. As an example, in a typical server, the memory subsystem may consume as much as ⅓ of the total power budget for a platform. Yet, up until now memory has not been incorporated in a platform power budget. So, even if a power cap is placed on the server, ⅓ of the power consumption resides outside the budget, which potentially significantly limits power saving opportunities.
Furthermore, even components that fall within the power budget are often not efficiently managed. Previously, static power capping limits may be set on components according to an overall budget. But the static limits typically include guard bands (headroom for error associated with static assumptions that are not dynamically tailored to a platform or component), which limit the potential for power savings. Moreover, such capping techniques are often worse for burst-like workloads, such as memory. As a result, there is currently no efficient way of dynamically translating a power limit to a domain and/or component that maximizes performance for a given power limit.

Method, apparatus, and system for energy efficiency and energy conservation including dynamic control of energy consumption in power domains


An apparatus and a method for processing high speed data using hybrid Direct Memory Access (DMA) are provided. The method includes determining a size of data to be transmitted, determining a memory access method of the data by comparing the determined size of the data with a first threshold, and determining an I/O bus access method of the data by comparing the determined size of the data with a second threshold.

1. Field of the Invention
The present invention relates to an apparatus and a method for processing high speed data using hybrid Direct Memory Access (DMA). More particularly, the present invention relates to an interface between a host processor and a peripheral Input/Output (I/O) unit for processing high speed data.
2. Description of the Related Art
DMA denotes a technique allowing a peripheral I/O unit to directly access a memory via a DMA controller without a host processor. DMA allows the peripheral I/O unit to operate even while the host processor performs an operation of a different process. Thus, DMA enhances data throughput and Central Processing Unit (CPU) use performance.
In a conventional art, as a method for accessing an I/O bus in order to transmit I/O data to a memory, only one of a DMA method, a non-DMA method, and a polling driving method or an interrupt driving method in case of the non-DMA method has been used. In the polling driving method and the interrupt driving method, a CPU provides a service to a peripheral I/O unit. In the interrupt driving method, a CPU provides a service only when a peripheral I/O unit requests the service. Therefore, the interrupt driving method is advantageous in the case where an amount of data to be transferred at one time via an I/O bus is large. On the other hand, in the polling driving method, a CPU monitors whether a peripheral I/O unit requires a service or whether the peripheral I/O unit is ready to receive a service using a predefined time interval. Therefore, the polling driving method is advantageous in the case where an amount of data to be transferred at one time via an I/O bus is small. That is, the polling driving method may provide better throughput in an aspect of data processing than the interrupt driving method, but has a poor tradeoff in the aspect of a bus occupancy rate.
A CPU sharing performance may be controlled depending on a selection of an I/O bus access method. When only one of the above methods for accessing an I/O bus is used, deterioration in a CPU use performance may result. For example, in the case where only the interrupt driving method is implemented, the interrupt driving method is also used in order to transfer small-sized data. In this case, since an additional overhead for interrupt processing is required despite small data, performance deterioration may result. On the other hand, in the case where only the polling driving method is implemented, during transmission of data having a size larger than a predefined size, other processors cannot share a resource because the resource is busy, and performance deterioration may result. Such limitations may be disadvantageous in an application where transmission of small-sized signaling data frequently occurs and high speed data transmission and excellent CPU use performance are required.
Therefore, a need exists for an apparatus and method for processing high speed data and improving a CPU use performance.

Apparatus and method for processing high speed data using hybrid DMA


The present invention is a method and apparatus for real time in-situ measuring of the downhole chemical and or physical properties of a core of an earth formation during a coring operation. The present invention comprises several embodiments that may use electromagnetic, acoustic, fluid and differential pressure, temperature, gamma and x-ray, neutron radiation, nuclear magnetic resonance, and mudwater invasion measurements to measure the chemical and or physical properties of the core that may include porosity, bulk density, mineralogy, and fluid saturations. The present invention comprises a downhole apparatus coupled to an inner and or an outer core barrel near the coring bits with a sensor array coupled to the inner core barrel for real time gathering of the measurements. A controller coupled to the sensor array controls the gathering of the measurements and stores the measurements in a measurement storage unit coupled to the controller for retrieval by a computing device for tomographic analysis.

1. Field of the Invention
The present invention relates generally to the field of subterranean formation evaluation during well coring operations. More specifically, this invention relates to measurement while coring techniques for the real time in-situ measurement of the chemical and or physical properties of a core during coring operations.
2. Description of the Related Art
Coring operations occur during the drilling of oil, gas, and water wells to recover parts of the subterranean earth formation (a core) for analysis of the chemical properties, physical properties, and or fluid saturations of the core within the earth formation. The downhole assembly for a coring operation generally comprises a coring bit, an inner and outer core barrel, and one or more stabilizers that provide weight on the core bit and stability to the entire downhole assembly during operation. As the coring proceeds, the coring operator periodically brings the inner core barrel, which also serves as a container for the core downhole, to the surface (a "trip") to remove the core for analysis at the surface.
When bringing the core from the bottom of the well hole to the surface, significant pressure and temperature changes occur that result in gas expansion as well as the evolution of gas from the oil. During this de-pressurization (the bringing to the surface) the chemical and or the physical properties of the core including the fluid saturations undergo a substantial change, which means that the analysis of the core at the surface will have some amount of error because of this change in the core from its down hole state. Pressure coring and Sponge Barrel coring are techniques used in the past to avoid the above problems. However, the use of these techniques is somewhat rare due to the expense involved in their use.
Another technique is to add mudwater tracers to the drilling mud to account for changes in the fluid saturation of the core due to flushing by the mud filtrate, depressurization, and other processes. The addition of the mudwater tracers to the drilling mud occurs at the surface, which allows the tracers to "invade" the core during the coring process. When recovered at the surface, the analysis of the core requires radially sectioning of the core, extraction, and searching for the tracer to monitor the mudwater invasion. This analysis technique is both time consuming and expensive and still may not provide accurate measurements as noted above, especially if the core contains the three fluid phases present in it. Another disadvantage of this technique is that it does not correct for any changes in the porosity of the rock.
Due to the high cost of coring, most chemical and or physical information about the subterranean earth formation comes from wireline downhole well logging. This method for measurement gathering involves lowering a measurement device attached to a wire into the drilling hole.
One problem with this type of measurement technique is that the sensor source and the sensor detector are both inside the borehole, which results in sending the measurement signal out into the general subterranean earth formation measure where the signal will reflect and scatter. As a result only a small volume of the earth formation near the wellbore responds to the applied sensor source. Even then, signal artifacts due to the borehole rugosity may cause large errors in the measurements. Another problem with this technique is that it does not define or restrict the volume of the earth formation investigated by the sensor signal very well. And finally, the analysis of the measurements gathered by this technique requires many semi-empirical corrections (to the measurements) to account for the poorly defined geometry and other factors including mud filtrate invasion.
The present invention is an apparatus and method for measuring the downhole chemical and or physical properties of the core during the coring operation. The present invention accomplishes this by appropriately instrumenting the core barrel with a downhole measurement device that allows the in-situ and real time measurement of the chemical and or physical properties of the core such as the porosity, bulk density, mineralogy, and also the fluid saturations of the core. The present invention offers many advantages over the prior techniques including the ability to measure the in-situ saturations of oil, water, and gas that are not currently possible with the current techniques. Additionally, the present invention offers an advantage over wireline downhole well logging because the sensor signal travels through the core within the inner core barrel, which is a known geometry (the inner core bore) unlike the earth formation along the well hole, that causes the sensor signal to scatter or reflect. Another advantage of the present invention is that it completes most if not all of the measurement gathering of the core before the core reaches the surface, which minimizes the cost of analyzing the core after it is at the surface.

Downhole in-situ measurement of physical and or chemical properties including fluid saturations of cores while coring


A method of operating a working machine of the kind including a body, a ground engaging structure, the body carrying a superstructure which is rotatable relative to the body about a first generally upright axis, the superstructure providing a mounting for a working arm which permits the working arm to be pivoted up and down about a generally horizontal axis and to be rotated about a second generally upright axis, the working arm including a mounting structure for releasably carrying at an outermost end thereof, a working implement, the method including providing on the machine a working implement holding device, and rotating the superstructure relative to the body about the first generally upright axis, and manipulating the working arm about the generally horizontal axis and the second generally upright axis to bring the working implement carried by the working arm into holding engagement with the holding device whereby the holding device holds the working implement, releasing the working implement from the mounting structure, and manipulating the working arm to move the mounting structure away from the holding device.

This invention relates to a method of operating a working machine of the kind which has a working arm with a working implement carried at an outermost end thereof.
So called "quick couplings" are know which permit a working implement to be readily and releasably mounted on the outermost end of a working arm. When thus carried by the working arm, the implement may be used by manipulating the working arm, which may include a plurality of pivotally connected components. The implement too may be manipulated to perform working operations. Typically such quick couplings enable a range of working implements conveniently to be severally fitted to the working arm, and preferably without the need for difficult manual handling of the implement.
It will be appreciated that such a working machine needs to be driven or transported around e.g. a construction site or other working environment, and may need to be driven or transported from site to site.
Current practice requires that working implements of the machine, which are not carried by the working arm and are required at different locations, are transported separately from the machine. Hence there is a need to load an implement transporter with the implements. This is all inconvenient, and inefficient.


An exchange member establishes a threshold credit value for transactions by a non-member institution. The threshold value is provided to a credit authorization service of the exchange, which acts as a surrogate for the exchange members. Securities transaction or orders from non-member institutions are then transmitted from the non-member institution to the credit authorization service of the exchange. The credit authorization service compares the transaction with a percentage of the pre-established threshold value. If the transaction does not exceed the percentage of the pre-established threshold, the system forwards the transaction to the exchange. If the transaction does exceed the percentage of the pre-established threshold, the system notifies the sponsoring exchange member and possibly the non-member institution. The percentage of the pre-established threshold may be less than or equal to 100 percent of the pre-established value. The exchange member has various opportunities to change the threshold value. The identity of the non-member institution and the identity of the exchange member may be removed or masked on the transaction.

1. Field of the Invention
The invention relates to the field of financial transactions and more particularly to the field of non-member institution securities transactions on a member securities exchange.
2. Description of the Related Art
In member exchange systems, securities transactions or orders are processed through exchange members before being exposed to the exchange floor for trading. Under the existing regulations and exchange rules, there is no opportunity for a non-member institution to directly submit a transaction to the exchange without submitting the transaction to a member first. Electronic order submission by the non-member institution may reduce order turn-around time, however, even where non-member institutions can electronically submit orders to the exchange through members, the non-member institution identity is typically included with the order, and therefore known or available on the floor. Non-member institutions want their identity to remain anonymous or hidden for at least as long as the order is being filled. Additionally, most non-member institutions executing transactions on the exchange would also like to stream-line the order submission process and reduce order turnaround time, wherever possible.
Accordingly, there is a need to maintain the anonymity of the institution or party placing the order, without violating the exchange regulations or rules, and reduce transaction execution times.

Method and system for credit authorization in a member exchange


Techniques for processing incoming signals conforming to a plurality of standards or communication formats with a single baseband receive section are disclosed. In one aspect, a plurality of analog processing components are adjusted in response to a format select signal, set according to one of a plurality of supported formats or standards. In another aspect, the operating mode of an A/D converter is tuned in response to the format select signal. In yet another aspect, the response characteristics of a jammer filter are tuned in response to the format select signal. In yet another aspect, the adjustment of the plurality of analog processing components is carried out by varying the frequency of a sample clock in response to the format select signal. Various other aspects are also presented. These aspects have the benefit of allowing a single baseband receive section to be deployed to process analog signals conforming to a plurality of communications standards or formats, in a power and area efficient manner.

Communication systems are deployed to facilitate communication between one or more devices, according to a pre-determined signaling process. The signaling processes often conform to a standard, whether the standard is proprietary or determined by an industry consortium. For example, wireless communication systems involve communication between a base station and a mobile unit through radio frequency (RF) transmission. These systems may be based on code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), or some other modulation techniques. Example CDMA standards include (1) the "TIA/EIA-95-B Mobile Station-Base Station Compatibility Standard for Dual-Mode Wideband Spread Spectrum Cellular System" (the IS-95 standard), (2) the standard offered by a consortium named "3rd Generation Partnership Project" (3GPP) and embodied in a set of documents including Document Nos. 3G TS 25.211, 3G TS 25.212, 3G TS 25.213, and 3G TS 25.214 (the W-CDMA standard), (3) the standard offered by a consortium named "3rd Generation Partnership Project 2" (3GPP2) and embodied in a set of documents including "C.S0002-A Physical Layer Standard for cdma2000 Spread Spectrum Systems," the "C.S0005-A Upper Layer (Layer 3) Signaling Standard for cdma2000 Spread Spectrum Systems," and the "C.S0024 cdma2000 High Rate Packet Data Air Interface Specification" (the cdma2000 standard), and (4) others. Other wireless systems, such as GSM, AMPS, and other TDMA systems are in use throughout the world. Additional wireless standards providing for various forms of wireless data connection include the IEEE 802.11 standard and Bluetooth.
In addition to wireless standards, there are standards for communication using wires or optical fiber. Each standard differs in at least one of a variety of ways, including frequency, bandwidth, modulation format, etc., and devices that communicate according a standard must support the various properties of that standard. Devices capable of supporting more than one standard are referred to as multi-mode or multi-standard devices. New standards emerge over time, and systems supporting various standards are deployed and active. Multi-standard devices allow a user to communicate in a broader geographical area, or with a greater variety of data speeds and features, than a device supporting only a single standard with its fixed set of features, and limited geographical deployment. As an example, in the field of wireless communications, nation-wide and world-wide roaming agreements between network operators deploying heterogeneous systems are driving demand for mobile stations which support the various standards deployed in their networks.
The baseband receive section in a receiver receives baseband analog signals and performs subsequent processing before generating digital output. Analog signals coming into the baseband receiver usually undergo a filtering operation to attenuate unwanted frequencies or noise, followed by an analog-to-digital (A/D) conversion.
In the past, baseband receivers have been designed to handle a single standard. Generalizing this approach for handling multiple standards may involve creating separate signal paths corresponding to each standard supported, each with its own circuitry. A byproduct of this approach may be that separate interfaces, each requiring programming for switching between the multiple supported modes may be required. Multiple signal paths, switches, registers, and interface software add complexity, cost, and power consumption that increase with the number of standards supported.
There is therefore a need in the art for a multi-standard baseband receiver that processes incoming signals conforming to a plurality of standards or communication formats in a cost, chip area, and power effective manner, with an interface that promotes programming efficiency and minimum complexity.