A method for driving an interlace system plasma display panel comprising applying a pulse higher than a discharge start voltage at the end of a sustain discharge period for a period in which only a cell that has executed a sustain discharge and cells adjacent to the former cell start discharge, executing an erase discharge of the cell that has executed the sustain discharge, and at times, the cells adjacent to the former cell, and when a given field is switched over to another field, executing a similar discharge, i.e., the whole surface write operation and a self-erase discharge, of the cell that has executed display before the switch-over of the given field before the whole surface write operation and the self-erase discharge are effected in the cell that is to execute display after the switch-over of the given field. This driving method applies a pulse having an opposite polarity of the polarity of the whole surface write pulse for a period longer than the pulse width of the sustain discharge pulse. On the other hand, an apparatus for driving a plasma display panel by using the driving method is also disclosed.

1. Field of the Invention
The present invention relates to a technology for driving a display panel including a group of cells as display devices having a memory function, and more particularly to a method for driving a plasma display panel and an apparatus for driving the same which are directed to an improvement in the contrast of an alternating current (AC) type plasma display panel. (Generally, the whole plasma display apparatus inclusive of the plasma display panel and peripheral circuits is referred to as a xe2x80x9cPDPxe2x80x9d.)
The AC type plasma display panel sustains discharge and carries out light emission display by alternately applying voltage waveforms of a plurality of pulses to two electrodes for sustaining this discharge. A discharge (lighting) operation for every discharge period finishes within a few micro-seconds (xcexcs) after the application of pulses. The ions defined as positive electric charges that are generated by this discharge operation are accumulated over an insulating layer on the electrode to which a negative voltage is applied, and electrons defined as negative electric charges are similarly accumulated over an insulating layer on the electrode to which a positive voltage is applied.
Therefore, if wall charges are first generated by causing the discharge by the pulses (write pulses) each having a relatively high voltage (write voltage) and then the pluses (sustain discharge pulses, that is, sustain pulses) each having a voltage lower than that of each of the write pulses (sustain discharge voltage) and an opposite polarity to each of the write pulses are applied to the electrodes, electric charges generated by the sustain pulses are superimposed on the wall charges previously accumulated by the write pulses so as to enhance the accumulated wall charges. As a result, the potential of the wall charges with respect to a discharge space becomes large and, at least, the above voltage exceeds a discharge threshold voltage at which the discharge starts. In other words, given cells that once effected the write discharge and have formed the wall charges have the characteristics that these cells sustain the discharge when the sustain discharge pulses are alternately applied thereto in opposite polarities. A phenomenon having the above characteristics is referred to as a xe2x80x9cmemory effectxe2x80x9d or xe2x80x9cmemory drivexe2x80x9d. The AC type plasma display panel carries out the display by utilizing this memory effect.
2. Description of the Related Art
The AC type plasma display panels can be classified into a two-electrode type which effects selective discharge (addressing discharge) and the sustain discharge by using two electrodes and a three-electrode type which effects addressing discharge by using a third electrode. In color plasma display panels for carrying out multi-gradation display, a phosphor inside the cells is excited by ultra-violet rays generated due to the discharge between different kinds of electrodes, but this phosphor involves the problem that it is extremely fragile against the impact of the ions defined as the positive charges that are generated simultaneously by the discharge. The former two-electrode type plasma display panel described above employs the construction in which the ions are allowed to collide directly with the phosphor and for this reason, the life of the phosphor is likely to become shortened. To avoid this problem, therefore, the latter three-electrode type plasma display panel utilizing a surface-discharge (that is, surface-discharge type plasma display panels) which is carried out between different electrodes that are located in the same plane, has been generally used in color plasma display panels.
Recently, an interlace system three-electrode type AC plasma display panel which is capable of providing a high definition display screen by reducing the pixel pitch (i.e., a space between adjoining cells) has recently attracted special attention. The method for driving the plasma display panel according to the prior art, etc, will be explained hereby with reference to FIGS. 1 to 9 that will be mentioned in the later-appearing xe2x80x9cBRIEF DESCRIPTION OF THE DRAWINGSxe2x80x9d in order to have the plasma display panel and its driving method according to the prior art more easily understood. The conventional method for driving the interlace system plasma display panel, etc, is typically described in Japanese Unexamined Patent Publication No. 9-160525 and No. 10-207417 corresponding to Japanese Patent Application No. 9-12700 filed on Jan. 27, 1997 by the same applicant (Fujitsu) as for the present invention. Such a driving method is referred to as the xe2x80x9cAlisxe2x80x9d (Alternate Lighting of Surfaces) method.
In a plasma display panel 10 having a schematic construction of a conventional surface-discharge type plasma display panel shown in FIG. 1, pixels are represented by dotted lines for only the display line (display row) L1. To simplify the explanation, the number of pixels of the plasma display panel 10 is assumed hereby as 6xc3x978=48 in terms of the monochromatic pixels. Incidentally, the present invention can be applied to both color display and monochromatic display, and one pixel of the color display corresponds to three pixels of the monochromatic display.
In order to facilitate the production of the plasma display panel and to provide high definition by reducing the pixel pitch, the plasma display panel 10 employs the construction in which the partitions in the row direction are removed from the conventional plasma display panels. To prevent the occurrence of the erroneous discharge due to influences between the adjacent display lines resulting from the removal of the partition, interlace scanning is carried out so that the voltage waveforms of the sustain pulses have mutually opposite phases between the odd-numbered rows and the even-numbered rows of the electrodes for surface-discharge as will be described later.
In FIGS. 2 and 3, a perspective view showing the state in which the opposing gap between the color pixels 10a of the plasma display panel shown in FIG. 1 is expanded and a longitudinal sectional view along a sustain electrode X1 of the color pixel 10a, is illustrated, respectively.
In FIGS. 2 and 3, transparent electrodes 121 and 122 of an ITO film, or the like, are disposed in parallel with each other on one of the surfaces of a glass substrate 11, and metal electrodes 131 and 132 of copper (Cu), or the like, are formed along the center line on the transparent electrodes 121 and 122 in order to reduce the voltage drop in the longitudinal direction of the transparent electrodes 121 and 122, respectively. The transparent electrode 121 and the metal electrode 131 together constitute the sustain electrode X1 while the transparent electrode 122 and the metal electrode 132 together constitute the scan electrode Y1. A dielectric member 14 for retaining the wall charges is deposited on the glass substrate 11 and the electrodes X1 and Y1, and an MgO protective film 15 is further deposited on the dielectric member 14.
Address electrodes A1, A2 and A3 and partitions 171 to 173 for partitioning these address electrodes are formed on the surface of the glass substrate 16 that opposes the MgO protective film 15 in the direction orthogonally crossing the sustain electrode X1 and the sustain electrode Y1. These partitions define discharge cells (which are also referred to merely as the xe2x80x9ccellsxe2x80x9d or xe2x80x9cslitsxe2x80x9d) in the regions where the addressing electrodes cross the sustain electrodes and the scan electrodes. A phosphor 181 emitting red light, a phosphor 182 emitting green light and a phosphor 183 emitting blue light when ultraviolet rays generated by the discharge are incident to them are deposited between the partitions 171 and 172, between the partitions 172 and 173 and between the partitions 173 and 174, respectively. A Ne+Xe Penning mixed gas, for example, is sealed into the discharge space between these phosphors 181 to 183 and the MgO protective film 15.
The partitions 171 to 174 function as spacers for preventing the ultra-violet rays generated by the discharge from being incident to the adjacent pixels and also for forming the discharge space. When the phosphors 181 to 183 are made of the same material, the plasma display panel 10 is a display panel for monochromatic display.
In an apparatus for driving a plasma display panel using the plasma display panel shown in FIG. 1, there are disposed a driving circuit for supplying a plurality of kinds of driving voltage pulses, that are necessary for writing predetermined display data to the selected cells, the sustain electrode, the scan electrode and the addressing electrode, and a control circuit for controlling the sequence of the supply of these driving voltage pulses. The driving circuit includes odd- and even-numbered X sustain circuits for supplying the write pulses and the sustain pulses to the sustain electrodes X1 to X5, odd- and even-numbered Y sustain circuits for supplying the scan pulses and the sustain pulses to the scan electrodes Y1 to Y4 and an addressing circuit for supplying the addressing pulses to the addressing electrodes A1 to A6.
In FIG. 4, a structural example of a frame for forming the color images of the plasma display panel shown in FIG. 1, is illustrated. In FIGS. 5A and 5B, a sequence of display scanning in the addressing period of the frame shown in FIG. 4, is illustrated.
The frame shown in FIG. 4 is divided into two fields, that is, an odd-numbered field and an even-numbered field. Each field comprises first to third subfields. In each sub-field of the odd-numbered field, the voltage having the waveform shown in the later-appearing FIG. 6 is supplied to each electrode of the plasma display panel 10 so as to cause the display lines L1, L3, L5 and L7 to display, and in each sub-field of the even-numbered field, the voltage having the waveform shown in the later-appearing FIG. 7 is supplied so as to enable the display lines L2, L4, L6 and L8 shown in FIG. 1 to display. The sustain discharge periods in the first to third sub-fields are T1, 2T2 and 4T1, respectively, and the sustain discharge is effected a number of times proportional to the length of the period in each sub-field. Consequently, the luminance has 8 (eight) kinds of gradations. Similarly, when the number of the sub-fields is 8 and the ratio of the sustain discharge periods is 1:2:4:8:16:32:64:128, the luminance has 256 kinds of gradations.
Scanning of the display lines in the addressing period is carried out in the number of sequence inside the white circle ◯ in FIG. 5A. In other words, the display lines are scanned in the sequence of L1, L3, L5 and L7 in the odd-numbered fields, and are scanned in the sequence of L2, L4, L6 and L8 in the even-numbered fields. Further, to reduce power consumption in the addressing period, it is possible to further divide each of the display lines L1, L3, L5 and L7 inside the odd-numbered fields into odd-numbered rows and even-numbered rows, and to scan serially one of these rows first and then to scan the other, as shown in FIG. 5B. This also holds true of the even-numbered fields.
In FIG. 6, the waveforms of the voltages applied to the electrodes in the odd-numbered fields in the first example of a conventional method for driving the plasma display panel, is illustrated. In FIG. 7, the waveforms of the voltages applied to the electrode in the even-numbered fields in the first example of the conventional method for driving the plasma display panel. Though the odd-numbered field and the even-numbered field have a plurality of sub-fields having mutually different sustain discharge periods in practice as shown in FIG. 4, the drawings show only one sub-field to simplify the related explanation.
First, a series of operations in the odd-numbered field will be explained with reference to FIG. 6. Symbols W, E, A and S in FIG. 6 represent the points of time in which the whole surface write discharge for all the cells, the whole surface self-erase discharge for all the cells, the addressing discharge and the sustain discharge occur, respectively. To simplify the explanation, the electrodes will be generically called as follows.
Sustain electrode (i.e. X electrode): electrodes X1 to X5 Odd-numbered sustain electrode: electrodes X1, X3 and X5 Even-numbered sustain electrode: electrodes X2 and X4 Scan electrode (i.e. Y electrode): electrodes Y1 to Y4 Odd-numbered scan electrode: electrodes Y1 and Y3 Even-numbered scan electrode: electrodes Y2 and Y4 Addressing electrode: addressing electrodes A1 to A6
On the other hand, symbols have the following meaning.
Vfxy: discharge start voltage between adjacent sustain electrode and scan electrode
Vfay: discharge start voltage between opposed addressing electrode and scan electrode
Vwall: voltage between positive wall charges and negative wall charges (wall voltage) due to wall charges generated by discharge between the adjacent sustain electrode and scan electrode
Typically, Vfxy=290V and Vfay=180V. Further, the voltage between the addressing electrode and the sustain electrodes is abbreviated as the voltage between the A-X electrodes and the voltage between the addressing electrode and the scan electrodes is abbreviated as the voltage between A-Y electrodes. Similar abbreviation will be used between other electrodes, too.
(1) Reset period
During the reset period, the voltage waveforms supplied to the sustain electrodes are the full surface write pulse (which is generally called the xe2x80x9cwrite pulsexe2x80x9d) and are mutually the same, the voltage waveforms supplied to the scan electrodes are 0V and are mutually the same, and the voltage waveforms supplied to the addressing electrodes are an intermediate voltage pulse and are mutually the same.
First, the applied voltage of each electrode is 0V. The positive wall charge exists on the lighting cells (pixels), that is, the MgO protective film 15 of the display slit on the sustain electrode side and the negative wall charge exists on the side of the scan electrodes (that is, the wall charges of the positive polarity remains) due to the last sustain pulse of the previous sustain discharge period of the reset period. The wall charges hardly exist on the side of the sustain electrode and on the side of the scan electrode of the cells which are in a lights-out state (i.e., an off state), that is, non-display slits.
The reset discharge pulse having a voltage Vw (that is, the write pulse) is supplied to the sustain electrode and an intermediate voltage pulse having a voltage Vaw is supplied to the addressing electrode during the period axe2x89xa6txe2x89xa6b. For example, Vw=310V and Vw greater than Vfxy. The whole surface write discharge for all the cells W (which is also called xe2x80x9call cell write dischargexe2x80x9d because the above write discharge is effected for all the cells irrespective of the lighting cells and the lights-out cells) between the adjacent X-Y electrodes, that is, between the X-Y electrodes of the display lines L1 to L8 irrespective of the existence of the wall charges. The wall charges having the opposite polarity (that is, the negative wall charges) occur as the resulting electrons and positive ions are extracted by the electric field due to the X-Y electrode voltage Vw, so that the field intensity of the discharge space decreases and the discharge finishes within one to several micro-seconds (xcexcs). Because the voltage Vaw is approximately Vw/2 and also because the voltage between the A-X electrodes and the voltage between the A-Y electrodes have mutually opposite phases but have a substantially equal absolute value, the average of the wall charges adhered to the phosphor by the discharge is substantially zero (0).
When the reset discharge pulse falls at t=b, that is, when the applied voltage having the opposite polarity to the wall voltage disappears, the wall voltage Vwall between the X-Y electrodes becomes larger than the discharge start voltage Vfxy, and the whole surface self-erase discharge E (which is also called xe2x80x9call cell self-erase discharge) occurs. In this instance, since the voltages of the sustain electrode, the scan electrode and the addressing electrode are 0V, it would be ideal that the wall charge is hardly generated by this whole surface self-erase discharge and the ions and the electrons are recombined with each other inside the discharge space to thereby accomplish complete neutralization. In practice, however, all the wall charges are not always neutralized completely in the whole surface self-erase discharge and a small amount of the wall charges having the negative polarity remain in the cells.
(2) Addressing period
In the addressing period, the voltage waveforms supplied to the odd-numbered sustain electrodes are mutually the same and the voltage waveforms supplied to the even-numbered sustain electrodes are mutually the same. Further, the voltage waveforms supplied to the non-selected scan electrodes are a voltage xe2x88x92Vsc and are mutually the same. The scan electrodes are selected in the order of Y1 to Y4, and a scan pulse having a voltage xe2x88x92Vy (that is, a scan pulse) is supplied to the selected scan electrodes while the non-selected scan electrodes are set to a voltage xe2x88x92Vsc. For example, Vsc=Vaxe2x88x9250V and Vy 4xe2x88x92150V.
In the condition (cxe2x89xa6txe2x89xa6d), the scan pulse of the voltage xe2x88x92Vy is supplied to the scan electrode Y1, and the addressing pulse of a voltage Va is supplied to the addressing electrodes of the cells required to be turned on. In this case, the relation Va+Vy greater than Vfay is established, and the addressing discharge occurs for only the cells required to be turned on, the wall charges having the opposite polarity occurs and the discharge finishes. At the time of this addressing discharge, the pulse of the voltage Vx is supplied to only the electrode X1 among the electrodes X1 and X2 adjacent to the electrode Y1. When the discharge start voltage between the X-Y electrodes triggered by this addressing discharge is Vxyt, the following relation is established:
Vx+Vsc less than Vxyt less than Vx+Vy less than Vfxy
The write discharge occurs between the X1-Y1 electrodes of the display line L1 and the wall charges of the opposite polarity, to an extent such that self discharge does not occur, are generated between the X1-Y1 electrodes and the discharge finishes. On the other hand, no discharge develops between the X2-Y2 electrodes of the display line L2.
In the condition (dxe2x89xa6txe2x89xa6e), the scan pulse of a voltage of xe2x88x92Vy is supplied to the electrode Y2, the pulse of the voltage Vx is supplied to the even-numbered sustain electrodes and the address pulse of the voltage Va is supplied to the addressing electrodes for the cells required to be turned on. Similarly, the write discharge occurs between the X2-Y2 electrodes of the display line L3, the wall charges of the opposite polarity are generated but no discharge develops between the X3-Y2 electrodes of the display line L4.
An operation similar to the above is thereafter executed in the same way at exe2x89xa6txe2x89xa6g.
The write discharge of the display data develops for the cells required to be turned on in the order of the display lines L1, L3, L5 and L7 and the positive wall charges are generated on the side of the scan electrode while the negative wall charges are generated on the side of the sustain electrode. In other words, the positive wall charges are generated in the selected cells (display slits) but no wall charges are generated in the non-selected cells (non-display cells).
(3) Sustain discharge period
A series of sustain pulses having the same phase and the same voltage Vs are supplied to the odd-numbered sustain electrodes and to the even-numbered scan electrodes during the sustain discharge period, and a series of sustain pulses having a phase deviated by 180xc2x0 (xc2xd cycle) from the former series are supplied to the even-numbered sustain electrodes and to the odd-numbered scan electrodes. On the other hand, the voltage Ve is supplied to the addressing electrodes in synchronism with the rising edge of the first sustain pulse and is held until the sustain discharge period is completed.
In the condition (h greater than t greater than p), the sustain pulse of the voltage Vs is supplied to the odd-numbered scan electrodes and the even-numbered sustain electrodes. The effective voltage of the cells between the odd-numbered electrodes Y and the odd-numbered electrodes X is Vs+Vwall, and the effective cell voltage between the even-numbered X-Y electrodes is Vsxe2x88x92Vwall. Further, the effective cell voltages between the odd-numbered X and even-numbered scan electrodes and between the even-numbered X and odd-numbered scan electrodes are 2Vwall, respectively. In this case, the following relation is established:
Vs less than Vfxy less than Vs+Vwall, 2Vwall less than Vfxy
The sustain discharge occurs between the odd-numbered Y electrodes and the odd-numbered X electrodes, the wall charges of the opposite polarity develop and the discharge finishes. No sustain discharge occurs between other electrodes. Therefore, the display is effective in only the odd-numbered display lines L1 and L5 inside the odd-numbered fields. The sustain discharge does not occur only this first time between the even-numbered Y electrodes and the even-numbered X electrodes.
In the condition (qxe2x89xa6txe2x89xa6r), the sustain pulse of the voltage Vs is supplied to the odd-numbered sustain electrodes and to the even-numbered scan electrodes. The effective voltages of the cells between the odd-numbered X and odd-numbered Y electrodes and between the even-numbered Y and even-numbered x electrodes are all Vs+Vwall, and the effective voltages between the odd-numbered Y and even-numbered X electrodes and between the odd-numbered X and even-numbered Y electrodes are zero. Consequently, the sustain discharge occurs between the odd-numbered X and odd-numbered Y electrodes and between the even-numbered Y and even-numbered X electrodes, and the wall charges having the opposite polarity occur, so that the discharge finishes. Therefore, display of all the odd-numbered display lines L1, L3, L5 and L7 of the odd-numbered fields becomes simultaneously effective.
Thereafter, the sustain discharge is repeated in the same way. In this case, as is obvious from the wall charges shown in FIG. 6, the effective voltages of the cells between the odd-numbered Y and even-numbered X electrodes of the non-display lines and between the odd-numbered X and even-numbered Y electrodes become zero. The last sustain discharge of the sustain discharge period is effected so that the polarity of the wall charges can return to the original state.
Next, the operation in the even-numbered fields will be explained. In FIG. 7, display of the display lines L1, L3, L5 and L7 of the pairs of the scan electrodes Y1 to Y4, and the sustain electrodes X1 to X4 respectively adjacent to the above scan electrodes in the upper positions, becomes effective in the odd-numbered fields as described above. In the even-numbered fields, display of the display lines L2, L4, L6 and L8 of the pairs of the electrodes Y1 to Y4, and the electrodes X2 to X5 respectively adjacent to the above scan electrode in the lower positions, may be effected. This can be accomplished by reversing the role of the electrode X1 and the electrode X2 for the electrode Y1, reversing the role of the electrode X2 and the electrode X3 for the electrode Y2, and so forth. In other words, the voltage waveforms supplied to the odd-numbered sustain electrodes and the even-numbered sustain electrodes that are grouped may be replaced with each other. FIG. 7 shows the waveforms of the voltages applied to the electrode in the even-numbered fields.
The operation in the even-numbered fields is obvious from the explanation given above and from FIG. 7. Generally speaking, the whole surface write discharge W and the whole surface self-erase discharge E are carried out in the reset period, the electrodes Y1 to Y4 are serially selected and the write discharge of the display data is effected in the order of the display lines L2, L4, L6 and L8 in the addressing period, and the simultaneous sustain discharge of these display lines L2, L4, L6 and L8 is repeated in the sustain discharge period.
Referring further to FIGS. 6 and 7, power consumption can be reduced if the number of pulses can be reduced. The number of pulses can be reduced if the pulses supplied to the odd-numbered sustain electrodes and the even-numbered sustain electrodes are rendered continuous during the addressing period. This can be accomplished by employing the arrangement shown in FIG. 5(B) for the scanning sequence. In other words, the display lines L1, L3, L5 and L7 inside the odd-numbered fields are further divided into the odd-numbered rows and the even-numbered rows, and after one of them is serially scanned, the other may be scanned. This also holds true of the even-numbered fields.
In the first example of the conventional interlace system plasma display panel driving method described above, the whole surface write discharge and the self-erase discharge are carried out every time in the reset period of each sub-frame and are not dependent on whether or not the sustain discharge is effected in the sustain discharge period immediately before this period. Therefore, background light emission becomes unnecessarily large and the contrast ratio is likely to decrease.
In FIGS. 8 and 9, timing charts useful for explaining the second example of a conventional interlace system plasma display driving method worked out in consideration of the problem described above, are illustrated.
FIGS. 8 and 9 show the waveforms of one frame comprising the odd-numbered fields and the even-numbered fields. Though the odd-numbered field and the even-numbered field have, in practice, a plurality of sub-fields having mutually different sustain discharge periods as shown in FIG. 4, the drawings show only one sub-field to simplify the illustration.
Each sub-field has the reset period, the addressing period and the sustain discharge period as shown in the drawings. When the immediately previous sub-field finishes, the wall charge corresponding to the display of this sub-field remains, and the reset discharge is conducted in the reset period at the start of the next sub-field. This reset discharge is a strong discharge which is generated by applying a voltage exceeding the discharge start voltage between the sustain electrode Xi (where i is a given natural number) and the scan electrode Yn (where n is a given natural number), and makes uniform the charge distribution of each discharge cell irrespective of the discharge state in the immediately previous sub-field. The second example of the prior art sets the potential of each electrode to a level exceeding the discharge start voltage for the display slits and to a level less than the discharge start voltage for the non-display slits.
To begin with, the operation in the odd-numbered fields shown in FIGS. 8 and 9 will be explained. In the odd-numbered field, the positive pulse Vs is applied to the odd-numbered sustain electrodes X1, X3, . . . , X2ixe2x88x921 (where i is a given natural number) and a negative pulse xe2x88x92Vu is applied to the odd-numbered scan electrodes Y1, Y2, . . . , Y2nxe2x88x921 (where n is a given natural number). At the same time, the negative pulse xe2x88x92Vu is applied to the even-numbered sustain electrodes X2, X4, . . . , X2I whereas the positive pulse Vs is applied to the Y2, Y4, . . . , Y2n. As a result, the potential difference between the odd-numbered sustain electrodes and the scan electrodes X1-Y1, X3-Y3, . . . , X2ixe2x88x921-Y2nxe2x88x921 as the display slits in the odd-numbered field and the even-numbered sustain electrodes and scan electrodes X2-Y2, X4-Y4, . . . , X2ixe2x88x92I-Y2n become Vs+Vu. When this potential difference Vs+Vu is set to a potential higher than the discharge start voltage between the electrodes, the reset discharge is effected in each display slit. On the other hand, the potential difference between the odd-numbered scan electrodes and the even-numbered sustain electrodes as the non-display slits in the odd-numbered fields, i.e. Y1-X2, Y3-X4, . . . , Y2nxe2x88x921-X2i is zero, and no discharge occurs. Therefore, in the second conventional example described above, the reset discharge is effected in only the display slits.
Incidentally, it has been customary to apply the pulse Vaw to the addressing electrodes with the application of the whole surface write pulse, but the application of this pulse Vaw becomes unnecessary, because the voltage applied to each sustain electrode and to each scan electrode becomes lower than in the prior art and a possibility of the occurrence of the discharge with the addressing electrodes does not exist.
Due to the reset discharge described above, the wall charges having the mutually opposite polarities are accumulated in excess on both the sustain electrode and the scan electrode. Therefore, the self-erase discharge occurs due to the wall charges themselves by setting the potentials of both electrodes to an equal voltage or more concretely, by setting both electrodes to the ground potential, to thereby neutralize the wall charges.
In the subsequent addressing period, the write discharge corresponding to the input data, that in turn corresponds to the display data, is effected. Here, a method is employed which first executes the write operation of the odd-numbered electrodes and then executes the write operation of the even-numbered electrodes. In other words, the scan pulse xe2x88x92Vy is serially applied to the odd-numbered electrodes Y1, Y3, . . . , Y2nxe2x88x921. Incidentally, the base pulse xe2x88x92Vsc is applied to each scan electrode Yn during the addressing period, and the scan pulse xe2x88x92Vy is superposed with the base pulse xe2x88x92Vsc. The addressing pulse Va is selectively applied to the addressing electrode Aj (where j is a given natural number) in accordance with the input signal, and the discharge is effected between this addressing electrode and the scan electrode Y2nxe2x88x921 to which the scan pulse xe2x88x92Vy is applied. In this instance, since the pulse Vx is applied to only the odd-numbered sustain electrodes X1, X3, . . . , X2ixe2x88x921 in the odd-numbered fields, the write discharge is effected only between the odd-numbered sustain electrodes and scan electrodes X1-Y1, X3-Y3, X2ixe2x88x921-Y2nxe2x88x921, and the wall charges are built up on both electrodes. Next, the scan pulse xe2x88x92Vy is serially applied to the even-numbered scan electrodes Y2, Y4, . . . , Y2n. Similarly, the data pulse Va is selectively applied to the addressing electrodes Aj and the pulse Vx is applied this time to only the even-numbered sustain electrodes X2, X4, . . . , X2i. Consequently, the discharge is effected between only the even-numbered sustain electrodes and scan electrodes X2-Y2, X4-Y4, . . . , X2i-Y2n, and the wall charges are accumulated on both electrodes.
In the subsequent sustain discharge period, the sustain discharge pulse Vs is alternately applied to the sustain electrodes Xi and the scan electrodes Yn constituting the display slits, so that the sustain discharge is executed in the discharge cells in which the write discharge is effected. In this instance, the voltage pulse having the same phase is applied to the sustain electrodes and the scan electrodes constituting the non-display slits lest the discharge occurs between the sustain electrodes and the scan electrodes constituting the non-display slits. In other words, the sustain discharge pulse is alternately applied in the odd-numbered fields between the odd-numbered sustain electrodes and scan electrodes X1-Y1, X3-Y3, . . . , X2ixe2x88x921-Y2nxe2x88x921 and between the even-numbered sustain electrodes and scan electrodes X2-Y2, X4-Y4, . . . , X2i-Y2n constituting the display slits, but this pulse has the same phase between the odd-numbered scan electrodes and the even-numbered sustain electrodes Y1-X2, Y3-X4, . . . , Y2nxe2x88x921-X2i and between the even-numbered scan electrodes and the odd-numbered sustain electrodes Y2-X3, Y4-X5, . . . , Y2n-X2ixe2x88x921 constituting the non-display slits.
Next, in the even-numbered fields, the display slits are so changed as to be positioned between the odd-numbered scan electrodes and the even-numbered sustain electrodes Y1-X2, Y3-X4, . . . , Y2nxe2x88x921-X2i and between the even-numbered scan electrodes and the odd-numbered sustain electrodes Y2-X3, Y4-X5, Y2n-X2ixe2x88x921. The impressed voltage to each display slit is the same as that of the odd-numbered field. In other words, the positive pulse Vs is applied this time to the odd-numbered scan electrodes Y1, Y3, . . . , Y2nxe2x88x921 while the negative pulse xe2x88x92Vu is applied to the even-numbered sustain electrodes X2, X4, . . . , X2i. At the same time, the negative pulse xe2x88x92Vu is applied to the even-numbered scan electrodes Y2, Y4, . . . , Y2n while the positive pulse Vs is applied to the odd-numbered sustain electrodes X1, X3, . . . , X2 ixe2x88x921. In consequence, the voltage differences between the odd-numbered scan electrodes and the even-numbered sustain elctrodes Y1-X2, Y3-X4, . . . , Y2nxe2x88x921-X2i and between the even-numbered scan electrodes and the odd-numbered sustain electrodes Y2-X3, Y4-X5, . . . , Y2n-X2ixe2x88x921 as the display slits in the even-numbered fields become Vs+Vu that exceeds the discharge start voltage between these electrodes, and the reset discharge is executed in each display slit.
On the other hand, the potential difference between the odd-numbered sustain electrodes and scan electrodes X1-Y1, X3-Y3, . . . , X2xe2x88x921-Y2nxe2x88x921 and the even-numbered sustain electrodes and scan electrodes X2-Y2, X4-Y4, . . . , X2-Y2n as the non-display slits in the even-numbered fields are both zero and no discharge occurs. Therefore, the reset discharge is executed in only the display slits. After this reset discharge is completed, the self extinction discharge occurs in the same way as in the odd-numbered fields, and the wall charges generated by the reset discharge are neutralized.
In the subsequent addressing period, too, the driving sequence is executed in the same way as in the odd-numbered fields described above with the exception that the display slits are changed. Therefore, the detailed explanation of the driving sequence in the addressing period in the even-numbered fields will be hereby omitted.
In the subsequent sustain discharge period, too, the sustain discharge pulse Vs is alternately applied to the sustain electrodes and the scan electrodes constituting the display slits in the same way as in the case of the odd-numbered fields described above, and the sustain discharge is executed in the discharge cells in which the write discharge is effected. Therefore, the detailed explanation of the driving sequence in the sustain discharge period in the even-numbered fields, too, will be hereby omitted.
As described above, according to the first example of the conventional driving method of the interlace system plasma display panel, the full surface write discharge and the self-erase discharge are executed every time for all the slits during the reset period of each sub-frame irrespective of the display slits (that is, the slits between the sustain electrodes that have executed the sustain discharge and the scan electrodes) and the non-display slits (that is, the slits between the sustain electrodes that have not executed the sustain discharge and the scan electrodes). Therefore, background light emission becomes larger than necessary level and the contrast ratio decreases, accompanied by the deterioration of display quality. Further, according to the second example of the conventional driving method of the interlace system plasma display panel, the voltage of the reset discharge pulse is so set as to exceed the discharge start voltage by only the display slits. Therefore, the decrease in the contrast ratio due to the unnecessary reset discharge in the non-display slits can be avoided.
However, even when the second example of the conventional plasma display panel driving method is employed, there is no alteration in that the whole surface write discharge and the self-erase discharge are executed every time in the reset period of each sub-frame and for this reason, a drastic improvement in the contrast ratio cannot be expected.
In view of the problems described above, it is an object of the present invention to provide a method for driving a plasma display panel, and an apparatus for driving the same, which can improve display quality by improving a contrast ratio of a display screen of a plasma display panel, and can guarantee a stable discharge of a next field when a given field is changed to another field.
When driving a plasma display panel comprising a plurality of sustain electrodes and a plurality of scan electrodes disposed in parallel with each other on a substrate for each display line; a plurality of addressing electrodes isolated electrically from the sustain electrodes and the scan electrodes and disposed in so as to cross the sustain electrodes and the scan electrodes; and discharge cells formed in areas in which the addressing electrodes cross the sustain electrodes and the scan electrodes, a method for driving a plasma display panel according to the present invention includes odd-numbered fields for carrying out display between odd-numbered sustain electrodes and odd-numbered scan electrodes and between even-numbered sustain electrodes and even-numbered scan electrodes, and even-numbered fields for carrying out display between the odd-numbered sustain electrodes and the even-numbered scan electrodes and between the even-numbered sustain electrodes and the odd-numbered scan electrodes.
Further, in the driving method described above, each of the odd-numbered and even-numbered fields includes a reset period for applying a predetermined voltage to the sustain electrode, the scan electrode and the addressing electrode and executing a reset discharge in a plurality of discharge cells in order to make uniform a charge distribution among a plurality of discharge cells uniform; an addressing period for executing a write discharge between the scan electrode and the addressing electrode in a selected one of discharge cell and executing a selective write operation in accordance with display data; and a sustain discharge period for applying alternately a sustain discharge pulse to the sustain electrode and the scan electrode in order to repeatedly execute discharge light emission for displaying the display data in the discharge cell in which the selective write operation is executed in the addressing period.
In the driving method of the plasma display panel described above, a reset discharge pulse having a voltage higher than a discharge start voltage necessary for starting the reset discharge is applied in the reset period to the sustain electrode and the scan electrode for the period in which the discharge is started in the discharge cell that has executed the sustain discharge and the discharge cells adjacent to the former discharge cell, and then the potential difference between the sustain electrode and the scan electrode is made substantially zero so that an erase discharge can be done for the cells that have executed the sustain discharge.
Preferably, in the driving method according to the present invention, the time for applying the reset discharge pulse having a voltage higher than the discharge start voltage is set to a value not larger than 2 xcexcs.
Preferably, further, in the driving method according to the present invention, an auxiliary erase pulse having a gentle slope is applied to the sustain electrode or the scan electrode after the passage of the period in which the potential difference between the sustain electrode and the scan electrode is made substantially zero.
Preferably, further, in the driving method according to the present invention, the auxiliary erase pulse described above is set to a pulse having a polarity opposite to that of the reset discharge pulse having a voltage higher than the discharge start voltage.
Preferably, further, in the driving method according to the present invention, the auxiliary erase pulse is a pulse having the opposite polarity to that of the voltage pulse having a voltage higher than the discharge start voltage.
Preferably, further, in the driving method of the present invention, the auxiliary erase pulse is a pulse having the same polarity as that of the pulse having a voltage higher than the discharge start voltage, and is applied to the sustain electrode or scan electrode different from the electrode to which the reset discharge pulse having a voltage higher than the discharge start voltage is applied.
Preferably, further, in the driving method of the present invention, the reset discharge pulse having a voltage higher than the discharge start voltage is applied to either one of the sustain electrode and the scan electrode.
Preferably, further, in the driving method according to the present invasion, the reset discharge pulses having a voltage higher than the discharge start voltage are applied at the same timing.
Preferably, further, in the driving method according to the present invention, a first sustain voltage pulse, which has an opposite polarity to that of the reset discharge pulse having a voltage higher than the discharge start voltage and has a width larger than that of the sustain discharge pulse described above, is applied before the reset discharge pulse having a voltage higher than the discharge start voltage is applied.
Preferably, further, in the driving method according to the present invention, a second sustain voltage pulse having a width larger than that of the sustain discharge pulse is applied for every other display line between the sustain discharge period and the first sustain voltage pulse applied before the application of the reset discharge pulse having a voltage higher than the discharge start voltage.
In the driving method according to the present invention, further, each of the odd- and even-numbered fields includes a reset period in which a predetermined voltage is applied to the sustain electrode, the scan electrode and the addressing electrode in order to make uniform the charge distribution among a plurality of discharge cells and to execute the reset discharge in each of a plurality of discharge cells; an addressing period in which the write discharge is executed in the selected discharge cell between the scan electrode and the addressing electrode and the selective write operation is made in accordance with the display data; and a sustain discharge period in which the sustain discharge pulse is alternately applied to the sustain electrode and the scan electrode in order to repeatedly execute discharge light emission for displaying the display data in the discharge cell in which the selective write operation is made in the addressing period.
When the odd-numbered field and the even-numbered field are switched over to each other, a reset process is executed so that the whole surface write discharge is executed by applying the reset discharge pulse having a voltage higher than the discharge start voltage to the pair of the sustain electrode and the scan electrode, that has executed, or is to execute, the sustain discharge and the self-erase discharge is effected at the point of time in which the reset discharge pulse having a voltage higher than the discharge start voltage is eliminated, and after this reset process is executed, another reset process is executed so that a voltage having the opposite polarity to that of the voltage of the whole surface write discharge and approximate to the sustain discharge pulse is applied for a period larger than the width of the sustain discharge pulse and furthermore, the reset discharge pulse having a voltage higher than the discharge start voltage is applied in the pair of the sustain electrode and the scan electrode that is to effect the sustain discharge in the next odd-numbered field or even-numbered field to thereby execute the whole surface write discharge, and the self-erase discharge is executed at the point of time in which the reset discharge pulse having a voltage higher than the discharge start voltage is eliminated.
Preferably, in the driving method according to the present invention, after the reset process described above is executed for the pair of the sustain electrode and the scan electrode of either one of the odd-numbered and even-numbered display lines among the pairs of the sustain electrodes and the scan electrodes that have executed, or are to execute, the sustain discharge, the reset process is executed for the other pair of the sustain electrode and the scan electrode, the voltage having the opposite polarity to that of the whole surface write discharge in the reset process described above and approximate to the voltage of the sustain discharge pulse is applied for a period at least equal to the pulse width of the sustain discharge pulse, the reset process is further applied to the pair of the sustain electrode and the scan electrode of either one of the odd-numbered and even-numbered display lines in the next odd-numbered field or the next even-numbered field, and then the reset process is executed for the other pair of the sustain electrode and the scan electrode.
On the other hand, in a plasma display panel including a plurality of sustain electrodes and a plurality of scan electrodes disposed in parallel with each other for each display line on a substrate, a plurality of addressing electrodes electrically isolated from the sustain electrodes and the scan electrodes and disposed so as to cross the sustain electrodes and the scan electrodes and discharge cells formed in areas in which the addressing electrodes cross the sustain electrodes and the scan electrodes, respectively, an apparatus for driving a plasma display panel according to the present invention includes odd-numbered fields for carrying out display between odd-numbered sustain electrodes and odd-numbered scan electrodes and between even-numbered sustain electrodes and even-numbered scan electrodes, respectively, and even-numbered fields for carrying out display between the odd-numbered sustain electrodes and the even-numbered scan electrodes and between the even-numbered sustain electrodes and the odd-numbered scan electrodes, respectively.
In the driving apparatus described above, each of the odd-numbered and even-numbered fields includes a reset period for executing a reset discharge inside a plurality of discharge cells by applying a predetermined voltage to the sustain electrodes, the scan electrodes and the addressing electrodes in order to make uniform the charge distribution among a plurality of discharge cells; an addressing period in which a write discharge is effected between the scan electrode and the addressing electrode in a selected discharge cell, and executing a selective write operation; and a sustain discharge period in which a sustain discharge pulse is alternately applied to the sustain electrode and the scan electrode in order to repeatedly execute discharge light emission for displaying display data in the discharge cell in which the selective write operation is effected in the addressing period described above.
Here, the apparatus for driving the plasma display panel according to the present invention includes driving means for supplying a reset discharge pulse for the reset discharge described above, an addressing pulse for effecting the write discharge described above and a sustain discharge pulse for effecting the sustain discharge to the sustain electrode, the scan electrode and the addressing electrode; and control means for controlling the sequence for supplying the reset discharge pulse, the addressing pulse and the sustain discharge pulse. The control means applies the reset discharge pulse having a voltage higher than a discharge start voltage necessary for starting the reset discharge to the sustain electrode or the scan electrode in the reset period for a period of time in which the discharge is started in only the discharge cell that has executed the sustain discharge and to the discharge cells adjacent to the discharge cell that has executed the sustain discharge, and in this way, makes the potential difference between the sustain electrode and the scan electrode substantially zero, so that an erase discharge can be executed for at least the cell that has executed the sustain discharge.
Further, the apparatus for driving the plasma display panel according to the present invention includes driving means for supplying a reset discharge pulse for effecting a reset discharge, the addressing pulse for effecting a write discharge and a sustain discharge pulse for effecting a sustain discharge to the sustain electrode, the scan electrode and the addressing electrodes described above; and control means for controlling the sequence of supplying the reset discharge pulse, the addressing pulse and the sustain discharge pulse:
When the odd-numbered field and the even-numbered field are switched over to each other, the control means executes a control so that the whole surface write discharge can be effected by applying a reset discharge pulse having a voltage higher than the discharge start voltage in the pair of the sustain electrode and the scan electrode that has executed, or is to execute, the sustain discharge, a self-erase discharge is effected at the point of time in which the reset discharge pulse having the voltage higher than the discharge start voltage is removed, a voltage having a polarity opposite to that of the voltage of the whole surface write discharge and approximate to the voltage of the sustain discharge pulse is applied for a period at least equal to the width of the sustain discharge pulse; and in the next odd-numbered field or the even-numbered field, the control means executes its control so that the whole surface write discharge can be effected in the pair of the sustain electrode and the scan electrode by applying the reset discharge pulse having a voltage higher than the discharge start voltage, and the self-erase discharge can be effected at the point of time in which the reset discharge pulse having a voltage higher than the discharge start voltage is eliminated.
According to the method for driving the plasma display panel and the apparatus for driving the same in the present invention, the reset discharge is executed by applying the voltage higher than the discharge start voltage to only the discharge cell that has executed the sustain discharge and the discharge cells adjacent to the former discharge cell for the period for starting the discharge when the interlace system driving sequence is executed, and the auxiliary erase pulse having a gentle slope is used thereafter to reliably eliminate the wall charges remaining between the sustain electrodes and the scan electrodes to zero, so that the erase discharge can be carried out mainly in the discharge cells that have executed the sustain discharge and in some case, in the discharge cells adjacent to the former discharge cells, too. Because the discharge is not effected for other discharge cells that do not effect the sustain discharge, on the other hand, stable driving can be accomplished with an improved contrast ratio.
When the odd-numbered fields and the even-numbered fields are switched over to each other in executing the interlace system driving sequence in the method for driving the plasma display panel and the apparatus for driving the same according to the present invention, the similar discharge is executed for the fields before switching, before the whole surface write discharge and the self-erase discharge are effected for the fields after switching of the fields, and thereafter the sustain discharge pulse is applied in the polarity opposite to that of the whole surface write pulse. Therefore, the reset discharge and the addressing discharge after switching of the fields can be executed stably.

Method for driving plasma display panel and apparatus for driving the same


An electronic metering apparatus for metering liquids with a drive, at least one displacer device with a displacer chamber and a displacer element arranged therein, which is connected to the drive, at least one holding device for a pipette point, which has a passage channel which is connected with the displacer chamber, a data memory with memory locations for different calibration data concerning different pipette points and/or different liquids and/or different usage conditions, an electric selection device for selecting calibration data, an electric control unit, which is connected to the electric selection device, the data memory, and to the electric drive motor of the drive and/or an electric display device, and which controls the movement of the displacer element by means of the electric motor and/or the display of the metering volume through the display device with recourse to the calibration data from the data memory, selected with the aid of the selection device, and an electric power supply.

The present invention is related to an electronic metering apparatus for metering liquids.
Known electronic metering apparatuses for metering liquids have a drive with an electric motor and an electronic display device, respectively, and a displacer device driven by the motor, which comprises a cylinder with a plunger arranged movable therein. The displacer device can be communicatingly connected to a replaceable pipette point. By means of the displacer device, an air cushion is dislocated, which aspirates liquid into the pipette point and ejects it from the same, respectively. Pipette points and syringes are preferably disposable objects for single use, made from a plastic material. The stroke volume of the plunger does not exactly correspond to the picked-up and delivered liquid volume. This is particularly due to the fact that the air column becomes somewhat longer through the weight of the liquid, so that the stroke volume exceeds the liquid volume.
From WO 2005/079988 A1, the entire contents of which is incorporated herein by reference, a pipette with an electronic display and a calibration function is known. The calibration function includes the input of an actually pipetted volume at a certain displayed volume into the control system of the pipette via a user interface. The control system calculates calibration data and memorizes them in a memory. By means of the calibration data, the stroke length of the plunger or the volume displayed by the display device is corrected, so that the displayed volume corresponds better to the actually metered volume. It is possible to memorize different calibration data in the control system, which are used for different pipetting functions (also called "modes of operation"), like direct pipetting or reverse pipetting. Direct pipetting includes the direct pick-up of the desired volume to be delivered, whereas reverse pipetting includes the pick-up of a volume which is greater than the desired volume to be delivered, which is delivered thereafter.
In the known pipette, a new calibration may become necessary, when one of the provided modes of operation is not selected but other conditions of operation are changed instead.
Departing from this, the present invention is based on the objective to provide an electronic metering apparatus, the use of which under different modes of operation is less impaired by calibrations.

Electronic metering apparatus for metering liquids


An apparatus for providing a set of spatial cues associated with an upmix audio signal having more than two channels on the basis of a two-channel microphone signal has a signal analyzer and a spatial side information generator. The signal analyzer is configured to obtain a component energy information and a direction information on the basis of the two-channel microphone signal, such that the component energy information describes estimates of energies of a direct sound component of the two-channel microphone signal and of a diffuse sound component of the two-channel microphone signal, and such that the directional information describes an estimate of a direction from which the direct sound component of the two-channel microphone signal originates. The spatial side information generator is configured to map the component energy information and the direction information onto a spatial cue information describing the set of spatial cues associated with an upmix audio signal having more than two channels.

Embodiments according to the invention are related to an apparatus for providing a set of spatial cues associated with an upmix audio signal having more than two channels on the basis of a two-channel microphone signal. Further embodiments according to the invention are related to a corresponding method and to a corresponding computer program. Further embodiments according to the invention are related to an apparatus for providing a processed or unprocessed two-channel audio signal and a set of spatial cues.
Another embodiment according to the invention is related to a microphone front end for spatial audio coders.
In the following, an introduction will be given into the field of parametric representation of audio signals.
Parametric representation of stereo and surround audio signals has been developed over the last few decades and has reached a mature status. Intensity stereo (R. Waal and R. Veldhuis, "Subband coding of stereophonic digital audio signals," Proc. IEEE ICASSP 1991, pp. 3601-3604, 1991.), (J. Herre, K. Brandenburg, and D. Lederer, "Intensity stereo coding," 96th AES Conv., February 1994, Amsterdam (preprint 3799), 1994.) is used in MP3 (ISO/IEC, Coding of moving pictures and associated audio for digital storage media at up to about 1.5 Mbit/s—Part 3: Audio. ISO/IEC 11172-3 International Standard, 1993, jTC1/SC29/WG11.), MPEG-2 AAC (, Generic coding of moving pictures and associated audio information—Part 7: Advanced Audio Coding. ISO/IEC 13818-7 International Standard, 1997, jTC1/SC29/WG11.), and other audio coders. Intensity stereo is the original parametric stereo coding technique, representing stereo signals by means of a downmix and level difference information. Binaural Cue Coding (BCC) (C. Faller and F. Baumgarte, "Efficient representation of spatial audio using perceptual parametrization," in Proc. IEEE Workshop on Appl. Of Sig. Proc. to Audio and Acoust., October 2001, pp. 199-202.), (, "Binaural Cue Coding—Part II: Schemes and applications," IEEE Trans. on Speech and Audio Proc., vol. 11, no. 6, pp. 520-531, November 2003.) has enabled significant improvement of audio quality by means of using a different filterbank for parametric stereo/surround coding than for audio coding (F. Baumgarte and C. Faller, "Why Binaural Cue Coding is better than Intensity Stereo Coding," in Preprint 112th Conv. Aud. Eng. Soc., May 2002.), i.e. it can be viewed as a pre- and post-processor to a conventional audio coder. Further, it uses additional spatial cues for the parametrization than only level differences, i.e. also time differences and inter-channel coherence. Parametric Stereo (PS) (E. Schuijers, J. Breebaart, H. Purnhagen, and J. Engdegard, "Low complexity parametric stereo coding," in Preprint 117th Conv. Aud. Eng. Soc., May 2004.), which is standardized in IEC/ISO MPEG, uses phase differences as opposed to time differences, which has the advantage that artifact free synthesis is easier achieved than for time delay synthesis. The described parametric stereo concepts were also applied to surround sound by BCC. The MP3 Surround (J. Herre, C. Faller, C. Ertel, J. Hilpert, A. Hoelzer, and C. Spenger, "MP3 Surround: Efficient and compatible coding of multi-channel audio," in Preprint 116th Conv. Aud. Eng. Soc., May 2004.), (C. Faller, "Coding of spatial audio compatible with different playback formats," in Preprint 117th Conv. Aud. Eng. Soc., October 2004.), and MPEG Surround (J. Herre, K. Kjörling, J. Breebaart, C. Faller, S. Disch, H. Purnhagen, J. Koppens, J. Hilpert, J. Rödén, W. Oomen, K. Linzmeier, and K. S. Chong, "Mpeg surround—the iso/mpeg standard for efficient and compatible multi-channel audio coding," in Preprint 122th Conv. Aud. Eng. Soc., May 2007.) audio coders introduced spatial synthesis based on a stereo downmix, enabling stereo backwards compatibility and higher audio quality. A parametric multi-channel audio coder, such as BCC, MP3 Surround, and MPEG Surround, is often referred to as Spatial Audio Coder (SAC).
Recently a technique was proposed denoted spatial impulse response rendering (SIRR) (J. Merimaa and V. Pulkki, "Spatial impulse response rendering i: Analysis and synthesis," J. Aud. Eng. Soc., vol. 53, no. 12, 2005.), (V. Pulkki and J. Merimaa, "Spatial impulse response rendering ii: Reproduction of diffuse sound and listening tests," J. Aud. Eng. Soc., vol. 54, no. 1, 2006.), which synthesizes impulse responses in any direction (relative to the microphone position) based on a single audio channel (W-signal of Bformat (M. A. Gerzon, "Periphony: Width-Height Sound Reproduction," J. Aud. Eng. Soc., vol. 21, no. 1, pp. 2-10, 1973.), (K. Farrar, "Soundfield microphone," Wireless World, pp. 48-50, October 1979.) plus spatial information obtained from the B-format signals. This technique was later also applied to audio signals as opposed to impulse responses and called directional audio coding (DirAC) (V. Pulkki and C. Faller, "Directional audio coding: Filterbank and STFTbased design," in Preprint 120th Conv. Aud. Eng. Soc., May 2006, p. preprint 6658.) DirAC can be viewed as a SAC, which is applicable directly to microphone signals. Various microphone configurations have been proposed for use with DirAC (J. Ahonen, G. D. Galdo, M. Kallinger, F. Kúch, V. Pulkki, and R. Schultz-Amling, "Analysis and adjustment of planar microphone arrays for application in directional audio coding," in Preprint 124th Conv. Aud. Eng. Soc., May. 2008.), (J. Ahonen, M. Kallinger, F. Küch, V. Pulkki, and R. Schultz-Amling, "Directional analysis of sound field with linear microphone array and applications in sound reproduction," in Preprint 124th Conv. Aud. Eng. Soc., May. 2008.). DirAC is based on Bformat signals and the signals of the various microphone configurations are processed to obtain B-format, which then is used in the directional analysis of DirAC.
In view of the above, it is the objective of the present invention to create a computationally efficient concept for obtaining a spatial cue information, while keeping the effort for the sound transduction reasonably small.

Apparatus, method and computer program for providing a set of spatial cues on the basis of a microphone signal and apparatus for providing a two-channel audio signal and a set of spatial cues

Fraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V.


A memory stores a log that includes first, second, and third datasets each containing server information collected at different times. The processor forms vectors from the datasets, calculates distance vectors between them and uses the distance vectors and pairwise angles between distance vectors to predict a dataset for a first future time. When the first future time arrives, the processor collects the server information, stores it in a fourth dataset, and calculates a variance between that dataset and the predicted dataset. Using the variance, distance vectors, and angles, the processor determines a second predicted dataset corresponding to a second future time, from which it determines a server usage prediction. If the server usage prediction is below a decommission threshold, the processor decommissions the server. If the server usage prediction is above a capacity threshold, the processor generates a report advising an administrator to upgrade or remove projects from the server.

Organizations commonly operate large data centers to provide centralized computational services to both their customers and internal users. Each project a customer/internal user of an organization wishes to execute using the data center's resources requires access to one or more of the data center's servers, provisioned with the appropriate operating system and software for the specific project. To meet computational demands, large data centers may contain thousands of servers.


A system, method, and computer program product are provided for collecting trace information based on a computational workload. The method includes the steps of compiling source code to generate a program, launching a workload to be executed by the parallel processing unit, collecting one or more records of trace information associated with a plurality of threads configured to execute the program, and correlating the one or more records to one or more corresponding instructions included in the source code. Each record in the one or more records includes at least a value of a program counter and a scheduler state of the thread.

Programmers use various debugging tools to analyze the source code that they generate in order to create more efficient programs. A plethora of debugging tools are available that enable programmers to analyze their programs. Some techniques include the utilization of trace tools to collect information about events generated by an application, operating system, driver, or hardware. Many processors enable such trace information to be collected. Trace information can be collected where the current program counter value for the active thread is sampled at periodic intervals such as every 10,000 cycles or when an event counter reaches a particular value (e.g., after every 100 cache misses, after 50 branch calls, etc.). Such collection methods may be enabled by hardware implemented within the processor such as the Performance Monitor included in the Intel® x86 family of CPUs or the ETM (Embedded Trace Macrocell) in some ARM® processors. In another instance, the application can be instrumented to collect such information (i.e., the driver may add instructions to the source code to collect call count and timing information for functions or basic blocks).
The techniques described above have been implemented in various microprocessors, but these techniques have their drawbacks. The embedded trace tools typically only collect information about the active threads (i.e., the one or two threads in a particular processor core that are issued during the current clock cycle). This may work for microprocessor architectures that only have a few active threads running at once, but this technique fails to collect information about the hundreds or thousands of stalled threads during any given clock cycle in today's graphics processing architectures. Similarly, instrumenting the application source code has its drawbacks as well. Tools may be used to modify already compiled binary code or software programmers may add explicit instrumenting instructions in the source code. Instrumenting the application in this manner may impact code generation, increase the size of the compiled program, and/or decrease performance of the code, therefore leading to different results than if the code were executed without such instrumentation.
Conventional parallel processing unit architectures do not include sufficient hardware infrastructure to collect trace information for the sheer number of threads being processed by the processing unit per clock cycle. For example, up to 120 instructions per cycle may be issued on many of today's GPUs, requiring a huge amount of memory bandwidth to transmit this data to a memory for analysis. The parallel processing unit architectures are also not optimized to handle interrupts without interfering with the performance of the program. Similarly, software instrumentation tends to also interfere with the operation of the program, thus skewing results compared with the execution of the program without instrumentation. Thus, there is a need for addressing these issues and/or other issues associated with the prior art.

System, method, and computer program product for collecting execution statistics for graphics processing unit workloads


A security document form such as a bank draft, or other document of value may incorporate a see-through and write-able hologram or diffractive grating as an anticounterfeit measure. The hologram may extend over all or a portion of the form such as the signature entry area and other data entry areas of the form, e.g. the date, name and numerical value areas. A Previous patent utilizing metallized holograms for such applications does not permit good photocopying or microfilming of the document on account of their high reflectance. This photocopying problem is solved by using a see-through, writable hologram which allows clearly legible photocopies to be made for legitimate use but appearing clearly fraudulent when passed off as the original. An ink-compatible top surface is made by coating with ink-receptive material or by corona discharge treatment as is well known in the industry. Writing or impact printing over the ink-compatible surface of the hologram partially occults the hologram underneath such writing and may cause the embossed surface of the hologram to become etched, so that even if the ink is somehow erased or removed, the writing trace would still remain, thus making it unalterable. The use of such an overlaminated hologram or diffractive grating can be accomplished by tamper-proof pressure sensitive holographic labeling, by hot-stamping the hologram with heat activated adhesive backing, or by embossing the hologram onto polymeric thermoplastic directly coated on the substrate paper or plastic card. The use of such a writable hologram also permits incorporation, of many other anticounterfeit features. Optionally, the hologram may also be covered with a protective laminate after the writing has been applied. This invention thus offer an aesthetically pleasing and cost effective means of forgery prevention for large volume users, while making it prohibitively costly for those attempting to counterfeit.

The ease with which modern computer graphic systems and high resolution copiers can generate high quality fake documents has caused a rapid and dramatic increase in document fraud. Commonly forged documents include checks, and other documents such as birth certificates, travelers checks, stock certificates, credit cards, receipts for valuables; government documents such as immigration papers, identification cards, social security cards, permits, licenses, tax documents, and other valuable documents such as property title papers, academic transcripts, diplomas, admission tickets, lottery tickets, etc. Holograms have been incorporated into security documents such as credit cards and driver licenses for many years to increase the difficulty of forging them. Holograms can be made very difficult to duplicate even for expert holographers. For examples, computer generated 2D or 3D holograms, in true color, in multiplexes, in many levels (up to 17), or holograms with covert images that are visible only under specific light or condition, etc.
Dennison discloses a method for mass-producing holograms for use with security documents (WO8903760) by coating thermoplastic onto metallized paper and/or heat-resistant plastic substrates which may be employed for embossing holograms or diffractive patterns at high speed. If non-holographic information or art work is to be printed over the top surface, the hologram can be covered with an ink-compatible layer to make it ink-receptive. However, such holograms are conventionally protected with a transparent laminate to preserve the integrity of the holograms and to deter their duplication.
A variety of patents have been issued for using non-continuous reflective holograms to deter forgery. For example, Malik U.S. Pat. No. 5,411,296 for laminating written personal data, photos, and the like between a substrate and a protected discontinuous hologram; Malik U.S. Pat. No. 5,145,212, for using analogous protected discontinuous holograms including a non-transparent structure of 2 side-by-side non-continuous holograms, each restructuring a separate image; Malik U.S. Pat. No. 5,142,383, for discontinuous metallized holograms including alpha-numeric shapes; and Malik U.S. Pat. No. 4,921,319 for surface relief holographic structure with reflection from an air interface created by adhesive or spacer and welded edges. Boswell (U.S. Pat. No. 5,464,690) for another example, describes a method of hot stamping finalized document with metallized hologram.
A magnetic layer or magnetic ink has also been used on holograms to increase the difficulty of forging. For examples, Sander (U.S. Pat. No. 4,631,222) describes a hot embossed holographic layer on top of a magnetic layer; Suess et al U.S. Pat. No. 5,383,687 disclose a method for producing an embossed holographic layer with an additional magnetic layer and a metallic layer.
With the exception of U.S. Pat. No. 5,267,753 which involves writable metallized holograms on checks, where the hologram is deliberately intended to be partially destroyed by the writing or printing, all the anticounterfeit holograms are covered with a protective top layer. In metallized holograms, however, the high reflectance from the reflective metal causes black blotches in photocopies when reproduced with a microfilm camera or photo-copier. This is an undesirable feature for the banking industry which microfilms or otherwise photocopies their checks daily. What is needed is a see-through writable hologram with lower reflectance that would permit microfilming and photocopying to yield a clearly legible copy for legitimate record purposes but clearly illegitimate when passed off as an original.
See-through holograms on paper or plastic substrate can be made by coating polymer/thermoplastic such as polypropylene, polyvinyl chloride, polyester, or styrene, etc. and embossing the hologram on it, as is well known in the industry. Slightly more reflective holograms can also be made by depositing very slight amount of metal, of the order of nanometer thickness. These polymeric layer can also accept additives to enhance counterfeit resistance while remaining essentially transparent and not too highly reflective as in the case of metallized holograms. There are several materials that are suitable as additives to the polymer used for fabricating a see-through and writeable holograms. Addition of such materials to the see-through writeable hologram can enhance their easy authentication and increase their counterfeit-resistance. Among these materials are:
(a) Thermochromic dyes that changes color upon temperature change (when pressed between two fingers, for example) can be added to the holographic polymeric resin or to the printing ink on the paper to be covered with the hologram. Borowski (U.S. Pat. No. 5,403,039), for example, describes a thermochromic printing ink for lottery tickets. In some cases, the stability of the dye can be improved by incorporating the dye in the plastic solid, or in others, by laminating it between protective layers. PA1 (b) Photochromic dyes that can reversibly change color upon exposure to light can be incorporated into the ink or into polymer comprising the hologram. Tagaya, et a, U.S. Pat. No. 5,474,715 for example, describe methods of incorporating photochromic material in thin film. PA1 (c) Fluorescent dyes with high extinction coefficients that can emit at specific wavelengths when excited with a light source at another specific wavelength. Such dyes can also be incorporated into polymeric resins used for making the hologram or printed on the document before covering it with the transparent hologram. Sachetti (U.S. Pat. No. 5,172,937), for example describes the use of fluorescent and phosphorescent dyes for attractive and protective labels. Fluorescent and phosphorescent compounds have been available from many companies such as SICPA Secureink Corporation, De la Rue Corp., etc.

Anticounterfeit documentation with see-through and write-able hologram


In some embodiments, an electronic device presents information about, and facilitates downloading of, featured applications in an app store application. In some embodiments, an electronic device facilitates browsing of applications and games by category. In some embodiments, an electronic device facilitates presentation of information about in-app purchases for a game or application in an app store application. In some embodiments, an electronic device facilitates the purchase of in-app purchases for the games or applications that are available on the electronic device. In some embodiments, an electronic device facilitates the download/purchase of games, applications and/or in-app purchases from outside of an app store application that is for browsing such content available on the electronic device. In some embodiments, an electronic device autoplays media content corresponding to applications (e.g., games, non-game applications, etc.) in an app store application so as to facilitate the ordered presentation of the media content to the user.

User interaction with electronic devices has increased significantly in recent years. These devices can be devices such as computers, tablet computers, televisions, multimedia devices, mobile devices, and the like.
In some circumstances, applications are downloadable to such a device, and user interaction with such a device entails browsing and downloading such applications to the device. Enhancing these interactions improves the user's experience with the device and decreases user interaction time, which is particularly important where input devices are battery-operated.

User interfaces for downloading applications on an electronic device


Methods and an apparatus for distributing digital content via a host receiver (e.g., direct-to-home satellite host receiver) are disclosed. The disclosed techniques include transmission of a host identifier and a client identifier from a host receiver and a client device to a satellite transmission station. The identifiers are used by the transmission station to lookup unique encryption keys associated with the host receiver and client device. The transmission station then transmits one or more encrypted keys to the host and/or client. In addition, the transmission station transmits encrypted content to the host. In turn, the host decrypts the content using one encryption key, re-encrypts the content using another encryption key, and passes the content along to the client device. By using the smart card, tuner, and/or storage device of the host receiver, the client device need not include a smart card, tuner, and/or storage device.

Information distribution systems, such as cable and satellite television systems, including transmission stations and reception stations have become so prevalent that most consumers take them for granted. The wide bandwidth available in some digital information distribution systems allows content providers to provide viewers with vast amounts of programming content. For example, while past conventional analog cable television systems provided viewers with tens of channels, modern satellite television systems, such as, for example, the DIRECTV® system provides viewers with literally hundreds of choices of programming content.
However, one drawback of satellite television systems is the need for a separate satellite receiver "box" for each television set. Almost all modern televisions are equipped to tune a plurality of analog channels received from an analog cable or terrestrial broadcast system. However, most televisions are not equipped to decode any channels received from a digital satellite system. In order to adapt a television to receive and decode channels from a digital satellite system, a satellite receiver is connected to the television.
The need for a separate satellite receiver for each television in a household greatly increases the cost of a satellite television system. The satellite receiver typically includes a satellite connection, a tuner, a decoder, a conditional access smartcard, as well as many other components. Some satellite receivers also include a hard disk (or other mass storage device) to record content for subsequent viewing. As a result, the per television cost of a satellite system typically exceeds the per television cost of an analog cable system.
If the consumer is asked to bear theses costs, the consumer may avoid adding additional televisions to his/her satellite system, or the consumer may choose not to install a satellite system altogether. On the other hand, if the satellite system provider bears these costs, the provider may need to charge more money and/or make less profit.

Methods and apparatus for distributing digital content


A system and process to deplete or remove oxygen in the ullage of a fuel tank to reduce the oxygen/fuel vapor ratio below a lower explosion limit by exposing the ullage compounds to an oxygen removal catalyst active at a relatively low temperature. The oxygen removal catalyst may be a non-precious metal catalyst. A selective reaction of the oxygen by the catalyst forms primarily alcohols, aldehydes, and/or ketones and produces less than about 5% water by volume. The selective reaction, occurring at the relatively low temperature, reduces the risk of flammability of the fuel.

This invention relates to an oxygen depletion and removal system (ORS) and a nitrogen generating system (NGS). This invention also relates to an on board inert gas generation system (OBIGGS), flammability reduction system (FRS), nitrogen generating system (NGS), and fuel tank inerting system (FTIS).
There are risks associated with the flammability of a fuel tank ullage composition. One approach to reducing the risk is to supply inert gas into the fuel tank. This reduces the oxygen concentration in the ullage and achieves an oxygen/fuel vapor ratio below the lower explosion limit (LEL).
Two ways to supply inert gas are by: 1) generating a nitrogen-enriched air (NEA) stream from outside air using an air separation membrane; and 2) generating a carbon dioxide stream from fuel. The first approach of using a membrane requires heavy, expensive membrane modules that require high pressure, cool, filtered air to operate efficiently. High pressure air is obtained from dedicated compressors, which add weight and use power; or from engine bleed air, which incurs a fuel penalty for the airplane. Cooling the air may require heat exchangers. Filtering the air requires removal of ozone and liquid and solid particulates by filters that require replacement.
The second approach, using CO2 has certain disadvantages. The production of CO2 consumes fuel. The fuel may also contain sulfur, which may form corrosive sulfur oxides. The production of CO2 from fuel also produces water, which needs to be removed from the carbon dioxide stream before being returned to the fuel tank. The second approach may also require a heater to operate efficiently.
The prior art includes a process discussed at a presentation in New Jersey on 2 Nov. 2005, titled Next Generation OBIGGS: Developments at Phyre Technologies. This process reduces oxygen content in the fuel tank by using oxygen as an oxidizing agent to produce CO2 and water. The process involves high temperature for catalytic oxidation and, as a result, a heat exchanger is needed to reduce the heating requirement and to cool the product before entering the fuel tank.
U.S. Pat. No. 3,847,298 ("the '298 patent") discloses the inerting of aircraft ullage by catalytic oxidation of liquid fuel with bleed air. FIG. 1 of the '298 patent illustrates the general process. A reactor is used to produce gas such as CO2 and H2O. The gas is then cooled by a cooling system or gas cooler. After the gas is cooled, it enters a moisture remover to remove H2O before the gas is recycled back to the fuel tank. The catalytic reaction occurs at high temperature −"500°/600° F."—as described at column 3, line 10 of the '298 patent. Moreover, the reactor operates in an open loop using engine bleed air to react with fuel from the tank.
U.S Patent Publication No. 2002/0028168 discloses inert gas production by combustion of an organic hydrocarbon fuel. This production is in an internal combustion engine followed by a catalytic process to substantially remove oxygen. As shown in FIG. 1, an exhaust stream from the engine passes through a heat exchanger to cool the exhaust gas, and the cooled exhaust gas stream is compressed with a compressor. The compressed gas is then heated and additional fuel is introduced into the exhaust gas stream. The heated and pressurized exhaust gas stream is then passed through a packed bed catalytic system to convert oxygen in the exhaust gas to CO2 and water vapor and thus produce inert gas containing less than 1000 ppm of oxygen.
As can be seen, there is a need for a low temperature, closed loop flow circuit that draws the ullage from the tank and passes the flow through the catalyst. There is also a need for use of a lighter, smaller catalyst; and a more cost-efficient way to reduce the oxygen/fuel vapor ratio in a fuel tank ullage that does not generate undesired by-products or use high pressures or temperatures, and does not create a fuel penalty by consuming fuel or using engine bleed air.


Continuous data protection is performed as two parallel processes: copying a data block from the storage device into the backup storage device (creating initial backup) and copying the data block to be written to the data storage into the incremental backup. When a write command is directed to a data storage block, it's intercepted and redirected to the backup storage, and data, which is to be written in accord to the write request, is written to the incremental backup on the backup storage. If write command is also directed to a data storage block identified for backup that has not yet been backed up, the identified data storage block is copied from the storage device to the intermediate storage device, the write command is executed on the identified data storage block from the storage device, and the data storage block is copied from the intermediate storage device to the backup storage device. In case of an error accessing a block on the storage device, the block is marked as invalid. The system suspends a write command to the storage device during the initial data backup process if the intermediate storage device has reached a selected data capacity; and copies a selected amount of data from the intermediate storage device to the backup storage device.

1. Field of the Invention
The present invention relates to continuous data protection, and more particularly, to continuously archiving data on storage devices and with preselected time intervals.
2. Background Art
Currently, there are a number of conventional methods that relate to organization of data archiving. One of these is a backup of the entire hard drive, which typically involves copying of the hard drive content onto some other medium, such as another hard disk drive, a DVD ROM, a DVD RAM, a flash disk, etc. The primary disadvantage of such a method is the need to backup what is frequently a very large amount of data, which, on the one hand, results in a relatively lengthy process of archiving, and, on the other hand, frequently requires relatively large available space for the archived data. This ultimately results in a relatively high cost of archiving per unit of archived data.
Another approach is often referred to as "incremental backup," which generally decreases the amount of space required for the archiving. With the incremental backup, typically the content of the hard disk drive is archived, or stored somewhere once. After that, only that data that has been changed, or added, since the previous backup, or since the pervious incremental backup, is actually archived. Recovery of data from the archive typically involves merging of the original backup and the various incremental backups.
For conventional backups it is possible to restore data to the point at which the backup was taken. In case of a system failure the data can be restored from the last incremental backup. In this case, data from the time of this incremental backup creation up to time of a system failure will be lost.
On the other hand, continuous data protection is different from traditional backups. In case of a continuous data protection an initial backup is created as in case of traditional backup, but new data (which is written on the storage device) is backed up in the incremental backup (so called a continuous incremental backup, or open-for-editing incremental backup) in parallel to writing on the storage device. In other words, data is backing up to the incremental backup during the process of data writing to the storage device, but not after the passage of some time, when a user decides to make a backup of data from the data storage device.
Vcom's Autosave provides a continuous data protection. However its technology is based on file level backup and thus its system cannot be restored after a critical system failure. Block level backup provides the backing up clusters on the data storage, but not the file as a whole, so, for a block level backup, less space is necessary.
Symantec's GoBack provides a continuous data protection on the block level backup. However, GoBack uses a buffer space for storage of its change files using FIFO (First In First Out). This limits the amount of data, and, eventually, how far back is possible to go back to restore. Thus, when the buffer space becomes full, GoBack starts to delete its earlier checkpoints and storage of earlier data.
Goback's technology is based on a file level monitoring and logging technique. It needs to consume a large chunk of the hard disk space to create a history change file. The monitoring system picks up every file change, regardless of whether or not it is worth it. A simple system restart will generate hundreds of file changes to log. The details of file change history logging consumes the hard disk space quickly and puts tremendous pressure on system resources.
Accordingly, there is a need in the art for an effective and efficient method of continuous backing up data, with minimal time and effort, so data backup process allows a computer system to remain online, with possibility to restore data from the backup in the point of time forewent the system failure and in the pre-selected point of restoration.

Method and system for continuous data protection


A process for separation of solid and liquid components in a distillation whole stillage utilizing airless spray drying is disclosed, which is more efficient and economical than conventional processes. In the process, distillation whole stillage resulting from distillation of fermented biomass is first subjected to an evaporation step for separating the whole stillage into a condensate and a concentrate including water, dissolved solids and suspended solids. The concentrate is then subjected to airless steam spray drying for converting the concentrate into dried solids, steam and vapors. All steam and vapors resulting from the airless steam spray drying step are then redirected as energy source to a processing step upstream of the airless spray drying step. At least some of the steam generated in the airless spray drying step is airless steam.

Efficient lingocellulose biomass conversion to ethanol results in a distillation whole stillage that has very fine residue particles (mostly lignin, protein and ash) that cannot be separated effectively or economically using typical separation equipment such as centrifuges due to the large volume of fluid in a typical plant. In known processes, the solid and liquid components are separated using a mechanical filter separator consisting of fine cloth presses squeezed together using hydraulic pressure created by electrical motors. The separated liquid portion from the filter press is then fed to an evaporator for further condensing and the solid portion to a conventional dryer or it is burnt as a wet energy material in a special boiler.
Whole stillage soluble solids left in the liquid portion are deleterious to recycling back into the lignocellulose biomass conversion process and must be removed and treated. Typical solid liquid separation technologies remove suspended solids only and allow the soluble solids to pass through the separation step. Treatment of lignocellulosic soluble solids (e.g. digestion) is not very effective in high yield enzymatic lingocellulose to ethanol conversion processes. Concentration of the soluble solids can be energy efficiently done with a multi effect evaporation train, but total water removal can not be achieved as the fluid becomes very vicious as the water is evaporated from the liquid. Thus, additional treatment such as an air dryer is required which consumes large amounts of energy and the additional treatment is complex due to the stickiness of the solids.
Equipment required to effectively perform solid liquid separation, such as a filter press, is expensive due to the large volume of biomass to process. Also, using a filter press is inefficient as it only removes about 50% of the liquid from the solids.
As such, the high moisture solids treated by filter press technology requires further drying in order for the solids to be used as a fuel in standard boiler combustion systems, otherwise the wet mixture can only be combusted using more complex fluidized bed combustion systems which are designed to handle higher amounts of water. The removal of liquid in this manner requires additional energy, usually in the form of heat energy derived from natural gas or coal, and electrical energy to run the hydraulic pumps that "squeeze" the solids in the filter press, which energy cannot be reused for other purposes effectively or economically, due to contamination of steam with air. When steam is contaminated with air, added energy is no longer fully reusable, since the steam then transfers heat to its surroundings at a lower temperature, making the transfer much less useful. As most of the work we to be done in an ethanol plant is to boil water, any condensing temperature below that of boiling water is not readily useful. This better understood from the below chart, which shows the impact of air in steam at various pressures.
Resulting Temperature - Air and Steam MixtureMixture0% AirPressure(Pure Steam)5% Air10% Air15% Air(psig)(bar)(° F.)(° C.)(° F.)(° C.)(° F.)(° C.)(° F.)(° C.)20.152191042161022131012109950.35227108225107222106219104100.7239115237114233112230110201.4259126256124252122249121
For example, when the mixture is dried for use in a standard combustion boiler and it is dried in a separate dryer, the steam used for drying cannot be recycled, since it contains too much air (normal condensing temperature is around 60 C as there is normally over 70% air), which means the drying costs are very high when using this standard drying technology.
Depending on the type of lignocellulosic feedstock, these drying and combustion systems may require thermal oxidizers to reduce odours emitted to the environment from volatile organic compounds within the mixture.
As such, the steps of evaporation and conventional drying require significant amounts of energy and post treatment and, consequently are expensive.
It is therefore desirable to provide a process for separation of solid and liquid components which requires less capital and is more energy efficient.