A liquid crystal display apparatus includes a circuit for generating an alternating signal and a correction time-period signal, the alternating signal indicating alternating of an opposed electrode voltage applied to an opposed electrode, the correction time-period signal indicating a time period during which a correcting voltage is applied to the opposed electrode voltage applied to the opposed electrode, and an opposed electrode voltage generating circuit that, in accordance with the alternating signal and the correction time-period signal and with respect to the alternated opposed electrode voltage applied to the opposed electrode, adds an upwardly convex correcting voltage to the alternated opposed electrode voltage when the alternated opposed electrode voltage is a positive polarity voltage, and subtracts the upwardly convex correcting voltage from the alternated opposed electrode voltage when the alternated opposed electrode voltage is a negative polarity voltage.

The present invention relates to a liquid crystal display. More particularly, it relates to a TFT liquid crystal display that allows display of high picture quality to be embodied with the use of a low voltage driving circuit. Also, it relates to the driving circuit therefor.
Referring to FIG. 2 and FIGS. 3A, 3B, the explanation will be given below concerning a conventional TFT liquid crystal display.
FIG. 2 is a block diagram for illustrating the conventional TFT liquid crystal display. Also, FIGS. 3A, 3B illustrate driving waveform diagrams for the conventional liquid crystal display.
In FIG. 2, a reference numeral 201 denotes an interface signal including display data and a synchronization signal that are transferred from a system (not illustrated). A numeral 202 denotes an interface circuit for generating display data and control signals that drive the conventional liquid crystal display. A numeral 203 denotes a signal driving circuit for generating a tone voltage corresponding to the display data. A numeral 204 denotes a scan driving circuit for selecting scanning lines in sequence. A numeral 205 denotes a power supply circuit for generating a power supply necessary for the operation of each block. Also, a numeral 206 denotes a liquid crystal panel on which there is executed a display corresponding to the display data inputted.
Of the signals that the interface circuit 202 generates, a numeral 207 denotes a control signal that controls the signal driving circuit 203 and includes the display data and the synchronization signal. A numeral 208 denotes a control signal that controls the scan driving circuit 204 and transfers a timing signal for scanning the scanning lines in sequence. A numeral 209 denotes a liquid crystal-applying voltage alternating signal xe2x80x9cMxe2x80x9d that is transferred to the power supply circuit 205.
Of the signals that the power supply circuit 205 generates, a numeral 210 denotes a tone voltage signal transferred to the signal driving circuit 203. The tone voltage signal 210 transfers a voltage that functions as a reference voltage of the tone voltage corresponding to the display data transferred to the liquid crystal panel 206. A numeral 211 denotes a scanning voltage signal transferred to the scan driving circuit 204. A numeral 212 denotes an opposed electrode voltage feeding line that transfers an opposed electrode voltage xe2x80x9cVcomxe2x80x9d to an opposed electrode of a liquid crystal 217 and an opposed electrode of a compensation capacitor 218. Here, the liquid crystals 217 and the compensation capacitors 218 constitute the liquid crystal panel 206. Moreover, a numeral 213 denotes a group of signal lines for transferring the tone voltage corresponding to the display data generated in the signal driving circuit 203. A numeral 214 denotes a group of scanning lines for transferring a scanning voltage that switches, into a selection or a non-selection state, each of the scanning lines generated in the scan driving circuit 204. A numeral 215 denotes pixels constituting the liquid crystal panel 206. The pixels 215 are formed at the intersection points of the group of signal lines 213 and the group of scanning lines 214, and thus the liquid crystal panel 206, eventually, has a matrix structure. Also, the numbers of the pixels 215 in the horizontal and the vertical directions are equivalent to the horizontal and the vertical resolutions. Incidentally, in general, in the case of a color liquid crystal display, the three primary colors, i.e., red, green and blue colors, constitute one pixel thereof. Accordingly, when the respective color pixels are arranged in the horizontal direction, the number of the pixels in the horizontal direction becomes equal to 3 times as large as the horizontal resolution. Also, the configuration employed commonly is that the pixels 215 arranged in the horizontal direction share one scanning line of the group of scanning lines 214 and the pixels 215 arranged in the vertical direction share one signal line of the group of signal lines 213. Furthermore, reference numerals within each of the pixels 215 denote the following components: 216 a thin film transistor (hereinafter, referred to as xe2x80x9cTFTxe2x80x9d), i.e., a switching element, 217 the liquid crystal, 218 the compensation capacitor, 219 a source electrode, 220 a between-gate/source parasitic capacitor configured between the scanning line (this is also referred to as xe2x80x9cgate linexe2x80x9d) 214 and the source electrode 219.
In FIGS. 3A, 3B, reference notations Vg(n), Vg(n+1) denote, of the group of scanning lines 214 illustrated in FIG. 2, driving waveforms of scanning lines that drive the nth line and the (n+1)th line, respectively. In addition, a notation Vgon denotes a selection voltage level, and a notation Vgoff denotes a non-selection voltage level. The notation Vcom indicates an ideal driving waveform of the opposed electrode voltage feeding line 212, and a notation Vcomh denotes a high electric potential voltage level and a notation VcomL denotes a low electric potential voltage level. A notation Vd indicates the tone voltage of the group of signal lines 213. When, with reference to the opposed electrode voltage Vcom, the tone voltage Vd is positioned on the negative polarity side, a voltage with negative polarity is applied to the pixel 215. Conversely, when the tone voltage Vd is positioned on the positive polarity side, a voltage with positive polarity is applied to the pixel 215. In the liquid crystal display, the electric potential difference between the opposed electrode voltage Vcom and the tone voltage Vd becomes equal to an effective voltage value applied to the liquid crystal 217. The effective voltage value causes the liquid crystal display to operate in such a manner that the luminance thereof is varied. Moreover, in the present embodiment, the explanation will be given based on the following characteristic: If the electric potential difference between the opposed electrode voltage Vcom and the tone voltage Vd is small, the display becomes a dark display (the example: black display) and if the electric potential difference is large, the display becomes a light display (the example: white display). In FIGS. 3A, 3B, the drain voltage Vd is the tone voltage executing the white display, and a notation VdWH denotes a white display drain voltage with positive polarity, and a notation VdWL denotes a white display drain voltage with negative polarity. When, with reference to the opposed electrode voltage Vcom, the drain voltage is positioned on the negative polarity side, an effective voltage value Vrms 1 is applied to the pixel. Conversely, when the drain voltage is positioned on the positive polarity side, an effective voltage value Vrms 2 is applied to the pixel.
Referring to FIG. 2 once again, the detailed explanation will be given below concerning the operation of the conventional TFT liquid crystal display.
The interface circuit 202 inputs the display data and the synchronization signal transferred by the interface signal 201. Then, the interface circuit 202 generates and outputs the control signal 207 to the signal driving circuit 203, the control signal 208 to the scan driving circuit 204, and the liquid crystal-applying voltage alternating signal M 209 to the power supply circuit 205. The signal driving circuit 203 fetches in sequence the display data by the amount of one horizontal line, using the display data and the synchronization signal transferred by the control signal 207. Then, after fetching the display data by the amount of one horizontal line, the signal driving circuit 203 outputs, simultaneously from the group of signal lines 213, the tone voltage corresponding to the fetched display data by the amount of one horizontal line. The signal driving circuit 203 continues outputting the tone voltage by the amount of one horizontal line during one horizontal time-period. Also, at this time, in parallel to the continuous outputting of the tone voltage, the signal driving circuit 203 executes an operation of fetching in sequence the display data of the next horizontal line.
Accordingly, it turns out that the display data that the interface circuit 202 outputs is converted into the tone voltage, then being outputted to the liquid crystal panel 206 during the next horizontal time-period. The signal driving circuit 203 repeats this operation, thereby outputting, to the liquid crystal panel 206, the tone voltage corresponding to the display data by the amount of one frame, i.e., by the amount of one screen. Also, the tone voltage that the signal driving circuit 203 outputs is generated by employing, as a reference voltage, the tone voltage transferred by the tone voltage line 210. In general, the reference voltage of the tone voltage transferred by the tone voltage line 210 is a voltage including a plurality of levels that range from the voltage for the black display to the voltage for the white display. Furthermore, the scan driving circuit 204 synchronizes with the control signal 208, thus applying a selection voltage to the group of scanning lines 214 from the 1st line in sequence. At this time, the selection voltage is applied to the TFT 216 in each of the pixels 215. As the result, the TFT 216 is switched into the selection state, thereby applying the tone voltage, which is transferred from each of the group of signal lines 213, to the liquid crystal 217 and the compensation capacitor 218. Then, if a non-selection voltage is applied to each of the scanning lines 214, the resultant non-selection state is maintained until it is switched back into the selection state next. In this way, in the liquid crystal display, the scanning is controlled in the sequence of the lines, and an amount of the light passing through the liquid crystal 217 is controlled at a voltage level of the effective voltage value applied to the liquid crystal 217. These controls have made it possible to embody the tone display.
Referring to FIGS. 3A, 3B once again, the explanation will be given below in more detail concerning the operation of applying the electric voltage to the liquid crystal 217 in the pixel 215. As illustrated in FIGS. 3A, 3B, if the selection voltage Vgon is applied to the scanning line G(n), the TFT 216 illustrated in FIG. 2 is switched into the xe2x80x9cONxe2x80x9d state. Then, as explained earlier, the drain (tone) voltage Vd transferred by the signal line 213 is applied to the liquid crystal 217 in the pixel 215. Meanwhile, if the non-selection voltage Vgoff is applied to the scanning line G(n), the TFT 216 is switched into the xe2x80x9cOFFxe2x80x9d state with this timing, and the voltage thereof is maintained. In the timing with which the selection voltage Vgon is applied to the scanning line G(n), the voltage level of the opposed electrode voltage feeding line 212 is the low electric potential voltage VcomL (negative polarity). Accordingly, the voltage applied to the liquid crystal turns out to be the voltage with positive polarity (The white display drain voltage is VdWH.). Similarly, in the timing with which the selection voltage Vgon is applied to the scanning line G(n+1), the voltage level of the opposed electrode voltage feeding line 212 is the high electric potential voltage VcomH (positive polarity). Accordingly, the voltage applied to the liquid crystal turns out to be the voltage with negative polarity (The white display drain voltage is VdWL.).
Generally speaking, it is required to apply an alternating voltage to the liquid crystal with a period of one frame (about 60 Hz). Consequently, in a line corresponding to each of the group of the scanning lines 214, it is required to apply, in a timing with which the voltage is applied next, a voltage the polarity of which is opposite to that of the voltage applied before. Furthermore, if the polarity of the tone voltage applied all over the surface of one screen is biased onto either of the two types of polarities, there occurs a flickering phenomenon called xe2x80x9cflickerxe2x80x9d. Accordingly, in the present embodiment, an alternating driving for each line has been embodied so that the tone voltage with positive polarity and that with negative polarity will be able to be applied for each line. Consequently, the voltage level of the opposed electrode voltage feeding line 212 alternates for each line the high electric potential voltage VcomH (positive polarity) and the low electric potential voltage VcomL (negative polarity).
The characteristic of the present conventional driving system is as follows: The present conventional driving system can be configured using the signal driving circuit 203 that has a dynamic range of the tone voltage Vd illustrated in FIGS. 3A, 3B, i.e., a withstand voltage that the tone voltage with either of the polarities can generate. This is made possible by the fact that, in the driving system, the opposed electrode voltage Vcom of the opposed electrode voltage feeding line 212 has been alternated. In contrast to this, in general, when applying the tone voltage with positive polarity and that with negative polarity to the liquid crystal, a signal driving circuit becomes necessary that has a dynamic range 2 times as long as the above-described dynamic range illustrated in FIGS. 3A, 3B.
Next, referring to FIGS. 4A, 4B to FIGS. 7A, 7B, the explanation will be given below regarding problems in the conventional liquid crystal display. FIGS. 4A, 4B illustrate driving waveform diagrams in the respective portions in the case where the white display is performed by the conventional liquid crystal display. FIGS. 5A, 5B illustrate driving waveform diagrams in the respective portions in the case where the black display is performed by the conventional liquid crystal display. FIG. 6 illustrates an example of a displayed screen at the time of being displayed by the conventional liquid crystal display. FIGS. 7A, 7B illustrate driving waveform diagrams in the case where the example of the displayed screen illustrated in FIG. 6 is displayed by the conventional liquid crystal display.
Both of FIGS. 4A, 4B illustrate operations of applying the white display voltage. FIG. 4A illustrates an example where the tone voltage with negative polarity is applied. FIG. 4B illustrates an example where the tone voltage with positive polarity is applied. In FIG. 4A, a reference notation Vg denotes a voltage waveform applied to the respective scanning lines. In addition, Vgon denotes the selection voltage level, and Vgoff denotes the non-selection voltage level. Vd indicates the tone voltage waveform applied to the respective signal lines. VdWH denotes the white display voltage with positive polarity, and VdWL denotes the white display voltage with negative polarity. Vcom 1 denotes an opposed electrode voltage waveform inputted into the liquid crystal panel 206, and Vcom 2 denotes the opposed electrode voltage waveform inside the liquid crystal panel 206. Vs denotes a source voltage waveform of the source electrode 219 in the pixel 215 inside the liquid crystal panel 206. Also, the reference notations in FIG. 4B are the same as those in FIG. 4A.
Both of FIGS. 5A, 5B illustrate operations of applying the black display voltage. FIG. 5A illustrates an example where the tone voltage with negative polarity is applied. FIG. 5B illustrates an example where the tone voltage with positive polarity is applied. In FIG. 5A, Vd indicates the tone voltage waveform applied to the respective signal lines. In addition, VdBH denotes a black display voltage with positive polarity, and VdBL denotes a black display voltage with negative polarity. The other waveforms are the same as those of the driving voltages illustrated in FIG. 4A. Also, the reference notations in FIG. 5B are the same as those in FIG. 5A.
FIG. 6 presents the example of the displayed screen in the case where an intermediate luminance is displayed all over the entire screen and a white rectangle is displayed at the central portion. In FIG. 6, there is illustrated a phenomenon that the luminances come to differ between intermediate luminance display regions xe2x80x9cBxe2x80x9d where the white rectangle is not displayed and display regions xe2x80x9cAxe2x80x9d that are located on the right and the left sides of the white rectangle. This phenomenon is a picture quality deterioration called xe2x80x9ctransverse smearxe2x80x9d, which, in the conventional liquid crystal display, occurs in the case of the low voltage driving that alternates the opposed electrode voltage to be applied to the opposed electrode voltage feeding line.
FIGS. 7A, 7B illustrate driving waveform diagrams in the respective portions in the example of the displayed screen illustrated in FIG. 6. FIG. 7A illustrates the driving waveform diagram in the intermediate tone display regions xe2x80x9cBxe2x80x9d illustrated in FIG. 6, and FIG. 7B illustrates the driving waveform diagram in the intermediate tone display regions xe2x80x9cBxe2x80x9d illustrated in FIG. 6. Additionally, in the present conventional embodiment, there are described both of the examples where the tone voltage with negative polarity is applied. In FIG. 7A, Vd indicates a voltage waveform in the intermediate luminance display. VdGH denotes an intermediate luminance display voltage with positive polarity, and VdGL denotes an intermediate luminance display voltage with negative polarity. The other waveforms are the same as those of the driving voltages illustrated in FIG. 4A. Also, the reference notations in FIG. 7B are the same as those in FIG. 7A.
Next, the detailed explanation will be given below regarding the occurrence mechanism of the transverse smear, i.e., the phenomenon that the variation in the luminance occurs in the display regions xe2x80x9cAxe2x80x9d that are located on the right and the left sides of the white rectangle as illustrated in FIG. 6.
In the case of the low voltage driving that alternates the opposed electrode voltage to be applied to the opposed electrode voltage feeding line, since the opposed electrode voltage feeding line is common to all the pixels, there can be said the following: When the opposed electrode voltage is the high electric potential voltage (positive polarity), in all the pixels on the lines into which the tone voltage is to be written, the tone voltage with negative polarity is applied. Also, when the opposed electrode voltage is the low electric potential voltage (negative polarity), in all the pixels on the lines into which the tone voltage is to be written, the tone voltage with positive polarity is applied. As the result, it turns out that there occurs an electric current concentration. This electric current concentration is such that, through the liquid crystals 217 and the compensation capacitors 218 in all the pixels 215, electric currents in all the pixels flow into or out of the opposed electrode voltage feeding line in one direction. At this time, a time constant of the opposed electrode voltage feeding line exerts influences, thereby causing a distortion to occur in the opposed electrode voltage. FIGS. 4, 5 reflect and illustrate the manner of this process.
In the driving waveform diagrams in FIGS. 4A, 4B and FIGS. 5A, 5B, as illustrated in FIG. 2, there exists the between-gate/source parasitic capacitor 220 in each of the pixels 215 in the liquid crystal panel 205. Capacitance of the parasitic capacitor 220 is caused by the TFT 216, and thus is concerned with insulating films and silicon (the both are not illustrated) of the TFT 216. When the scanning line is transitioned from the selection state to the non-selection state, the TFT 216 is switched from the xe2x80x9cONxe2x80x9d state to the xe2x80x9cOFFxe2x80x9d state. At this time, the voltage that has been applied to the liquid crystal 217 and the compensation capacitor 218 is distributed to the parasitic capacitor 220 as well, since the above-described insulating films and silicon can also be regarded as capacitors.
Assuming that the capacitance of the parasitic capacitor 220 is Cgs, equivalent capacitance of the liquid crystal 217 is Clc, capacitance of the compensation capacitor 218 is Cstg, and the selection voltage of the scanning line is Vgon, xcex94Vgs, i.e., the voltage that has moved to the parasitic capacitor, is given by the following formula (1):
xcex94Vgs=(Cgs/(Cgs+Ccl+Cstg))xc3x97Vgonxe2x80x83xe2x80x83(1)
Consequently, it has been found that the voltage applied to the liquid crystal 217 drops by the amount of the voltage that has moved to the parasitic capacitor 220. This requires that Vcom 1, i.e., the opposed electrode voltage to be applied to the opposed electrode voltage feeding line, be shifted in advance down to a lower electric potential level by the amount of the voltage that will drop because of the influence of the parasitic capacitor 220.
Next, the explanation will be given below concerning operations of the respective voltage waveforms in pursuit of time. When applying VdWL, i.e., the white display voltage with negative polarity illustrated in FIG. 4A, if the selection voltage Vgon is applied to the scanning line, during a time-period xe2x80x9cT1xe2x80x9d, the source voltage vs is transitioned to the voltage level of the drain voltage Vd in the previous line (Vs is shifted up to a higher electric potential.). After that, if the opposed electrode voltage is alternated during a time-period xe2x80x9cT2xe2x80x9d, as illustrated in FIG. 4A, the source voltage Vs is shifted up to a higher electric potential in response to the alternating of the opposed electrode voltage. This is due to the fact that the variation in the opposed electrode voltage is steeper than writing speed of the TFT 216. After that, during time-periods xe2x80x9cT3xe2x80x9d, xe2x80x9cT4xe2x80x9d, the source voltage Vs is transitioned to the electric potential of the drain voltage Vd. Here, during the time-period xe2x80x9cT3xe2x80x9d, the source voltage Vs lies in a higher electric potential state than the opposed electrode voltage Vcom 2 inside the liquid crystal panel 206, and during the time-period xe2x80x9cT4xe2x80x9d, the source voltage Vs falls in a lower electric potential state than the opposed electrode voltage Vcom 2 inside the liquid crystal panel 206. In this operation, the source voltage electric potential is positioned at a considerably higher electric potential level as compared with the opposed electrode voltage electric potential. This increases the voltage distortion in the opposed electrode voltage, thus slowing down the convergence rate. Accordingly, in the timing with which the time-period xe2x80x9cT4xe2x80x9d is over, i.e., the timing with which the non-selection voltage Vgoff is applied to the scanning line, the electric potential difference between the source voltage Vs and the opposed electrode voltage Vcom 2 plays a role of VrmsWL 1, i.e., the effective voltage value to be applied to the liquid crystal 217. In the present conventional embodiment, the opposed electrode voltage Vcom 2 inside the liquid crystal panel 206 does not attain to the desired opposed electrode voltage Vcom 1. This generates an electric potential difference xcex94VcomH, which appears as a lack of the effective voltage value. Also, if the TFT 216 is transitioned to the xe2x80x9cOFFxe2x80x9d state, there occurs the above-described diving phenomenon of the voltage into the parasitic capacitor 220. This diving voltage level becomes equal to xcex94VgsWL. Thus, eventually, the resultant effective voltage value to be applied to the liquid crystal 217 becomes equal to xe2x88x92VrmsWL2 (=xe2x88x92VrmsWL1xe2x88x92xcex94VgsWH). Also, in this effective voltage value, there has occurred the lack of the effective voltage value that is equivalent to xcex94VcomH. This is because, as described above, the opposed electrode voltage Vcom 2 inside the liquid crystal panel 206 is lacked by the amount of xcex94VcomH as compared with the desired opposed electrode voltage Vcom 1.
Similarly, when applying VdWH, i.e., the white display voltage with positive polarity illustrated in FIG. 4B, if the selection voltage Vgon is applied to the scanning line, during a time-period xe2x80x9cT1xe2x80x9d, the source voltage vs is transitioned to the voltage level of the drain voltage Vd in the previous line (Vs is shifted up to a higher electric potential.). After that, during a time-period xe2x80x9cT2xe2x80x9d, alternating the opposed electrode voltage transitions the source voltage down to a lower electric potential voltage. Since the variation in the opposed electrode voltage is steeper than the writing speed of the TFT 216, as illustrated in FIG. 4B, the source voltage Vs is shifted down to the lower electric potential in response to the alternating of the opposed electrode voltage. After that, during time-periods xe2x80x9cT3xe2x80x9d, xe2x80x9cT4xe2x80x9d, the source voltage Vs is transitioned to the electric potential of the drain voltage Vd. Here, during the time-period xe2x80x9cT3xe2x80x9d, the source voltage Vs lies in a lower electric potential state than the opposed electrode voltage Vcom 2 inside the liquid crystal panel 206, and during the time-period xe2x80x9cT4xe2x80x9d, the source voltage Vs rises in a higher electric potential state than the opposed electrode voltage Vcom 2 inside the liquid crystal panel 206. In this operation, the electric potential difference between the opposed electrode voltage and the drain voltage has become larger than that in the above-described case illustrated in FIG. 4A where the tone voltage with negative polarity is applied. This condition increases amount of writing voltage during the time-period xe2x80x9cT4xe2x80x9d. Accordingly, the opposed electrode voltage Vcom 2 does not attain to the desired opposed electrode voltage Vcom 1, thus generating an electric potential difference xcex94VcomL. Consequently, the effective voltage value to be applied to the liquid crystal 217 becomes VrmsWH1, and thus it turns out that there has occurred a lack of the effective voltage value that is equivalent to xcex94VcomL. Also, if the TFT 216 is transitioned to the xe2x80x9cOFFxe2x80x9d state, there occurs the diving phenomenon of the voltage because of the above-described influence of the parasitic capacitor 220. This diving voltage level becomes equal to xcex94VgsWH. Thus, eventually, the resultant effective voltage value to be applied to the liquid crystal 217 becomes equal to VrmsWH2 (=VrmsWH1xe2x88x92xcex94VgsWL). Accordingly, it turns out that, on account of the insufficiency in the convergence of the opposed electrode voltage Vcom 2, there has occurred the lack of the effective voltage value that is equivalent to xcex94VcomL.
Next, referring to FIGS. 5A, 5B, the explanation will be given below regarding the manner in which the black display voltage is applied. When applying VdBL, i.e., the black display voltage with negative polarity illustrated in FIG. 5A, if the selection voltage Vgon is applied to the scanning line, during a time-period xe2x80x9cT1xe2x80x9d, the source voltage Vs is transitioned to the voltage level of the drain voltage Vd in the previous line (Vs is shifted up to a higher electric potential.). After that, during a time-period xe2x80x9cT2xe2x80x9d, the opposed electrode voltage is alternated and, as illustrated in FIG. 5A, the source voltage Vs is shifted up to a higher electric potential in response to the alternating of the opposed electrode voltage. After that, during a time-period xe2x80x9cT3xe2x80x9d, the source voltage Vs is transitioned to the electric potential of the drain voltage Vd. Then, during a time-period xe2x80x9cT4xe2x80x9d, the source voltage Vs is stabilized and, at this point in time, the effective voltage value applied to the liquid crystal 217 is VrmsBL1. Here, taking a diving voltage xcex94VgsBL into consideration, it is found that the effective voltage value applied to the liquid crystal 217 in the holding state becomes xe2x88x92VrmsBL2 (=VrmsBL1xe2x88x92xcex94VgSBL). Namely, this means the following: The opposed electrode voltage Vcom 1 has been shifted onto the lower electric potential side. Accordingly, when the TFT 216 lies in the xe2x80x9cONxe2x80x9d state, the source voltage Vs is positioned nearer to the positive polarity side than the opposed electrode voltages Vcom 1, Vcom 2. Then, the TFT 216 is transitioned to the xe2x80x9cOFFxe2x80x9d state. This causes the diving voltage to occur, thereby changing the effective voltage value VrmsBL1 into the tone voltage with the negative polarity. In addition to this, in comparison with the case illustrated in FIG. 4A where the white display voltage is applied, the electric potential variation in the source voltage Vs is infinitesimal during the time-period xe2x80x9cT2xe2x80x9d. This condition enhances the convergence rate at which the opposed electrode voltage Vcom 2 converges onto the desired opposed electrode voltage Vcom 1. Consequently, there occurs none of the variation in the effective voltage value on account of the insufficiency in the convergence of the opposed electrode voltage Vcom 2.
When applying VdBH, i.e., the black display voltage with positive polarity illustrated in FIG. 5B, if the selection voltage Vgon is applied to the scanning line, during a time-period xe2x80x9cT1xe2x80x9d, the source voltage Vs is transitioned to the voltage level of the drain voltage Vd in the previous line (Vs is shifted up to a higher electric potential.). After that, during a time-period xe2x80x9cT2xe2x80x9d, the opposed electrode voltage is alternated and, as illustrated in FIG. 5B, the source voltage Vs is shifted down to a lower electric potential in response to the alternating of the opposed electrode voltage. After that, during time-periods xe2x80x9cT3xe2x80x9d, xe2x80x9cT4xe2x80x9d, the source voltage Vs is transitioned to the electric potential of the drain voltage Vd, and the source voltage Vs is stabilized. In comparison with the case illustrated in FIG. 4B where the white display voltage is applied, the electric potential variations in the source voltage Vs and the opposed electrode voltage Vcom 2 are small enough. This condition decreases the amount of the writing voltage, thus enhancing the convergence rate at which the opposed electrode voltage Vcom 2 converges onto the desired opposed electrode voltage Vcom 1. Assuming that the effective voltage value applied to the liquid crystal 217 is VrmsBH1 during the time-period xe2x80x9cT4xe2x80x9d and taking a diving voltage xcex94VgsBH into consideration, it is found that the effective voltage value applied in the holding state becomes xe2x88x92VrmsBH2 (=VrmsBH1xe2x88x92xcex94VgsBH). As is the case with the description in FIG. 5A, there occurs none of the variation in the effective voltage value on account of the insufficiency in the convergence of the opposed electrode voltage Vcom 2.
In this way, in the state where the electric potential difference between the opposed electrode voltage Vcom and the drain voltage Vd is large, the voltage distortion in the opposed electrode voltage Vcom becomes larger. As the result, there occurs the lack of the effective voltage value toward the liquid crystal 217. Conversely, in the state where the electric potential difference between the opposed electrode voltage Vcom and the drain voltage Vd is small, the voltage distortion in the opposed electrode voltage Vcom becomes smaller. As the result, there occurs no lack of the effective voltage value toward the liquid crystal 217.
Next, the explanation will be given below regarding causes of the picture quality deterioration illustrated in FIG. 6, referring to FIGS. 7A, 7B and taking into consideration the voltage-applied state in the white display and the voltage-applied state in the black display.
In the lines in the regions (A) illustrated in FIG. 6, the white display data are included in the display data in the horizontal direction. This condition causes the opposed electrode voltage waveform Vcom 2 inside the liquid crystal panel 206 to take on a voltage waveform as illustrated in FIG. 7A. Namely, there occurs a voltage variation in the opposed electrode voltage Vcom 2 that is attributed to the white display, and thus there occurs a lack of the effective voltage value that is equivalent to xcex94VcomGH as compare with the desired opposed electrode voltage Vcom 1.
Similarly, in the lines in the regions (B) illustrated in FIG. 6, all the display data in the horizontal direction are the intermediate tone display data. This condition causes the opposed electrode voltage waveform Vcom 2 inside the liquid crystal panel 206 to take on a voltage waveform as illustrated in FIG. 7B. Namely, it turns out that the opposed electrode voltage Vcom 2 attains to the desired opposed electrode voltage Vcom 1. Accordingly, even in the same intermediate luminance display, the effective voltage value applied to the liquid crystal 217 in the holding state becomes different by the amount of xcex94VcomGH, and thus there occurs a lack of the effective voltage value. As the result, the white display data are included in the display data in the horizontal direction, and thus the intermediate luminance of the lines becomes dark display. Consequently, the difference in the effective voltage value, i.e., the amount equivalent to the insufficiency in the convergence of the opposed electrode voltage, is able to be recognized by the human eyes as the variation in the luminance, then being perceived as the transverse smear explained earlier.
Next, based on FIGS. 8 to 12, the further explanation will be given below concerning another conventional embodiment of a liquid crystal display. By the way, the configuration components in a circuit illustrated in FIG. 8 are the same as those in the conventional embodiment illustrated in FIG. 2 except for a compensation electrode 213. Accordingly, here, the explanation will be given regarding only the points that differ from those in the embodiment in FIG. 2.
In FIG. 9, a reference notation G1 denotes, of a group of scanning lines 214 illustrated in FIG. 8, a driving waveform of a scanning line that drives the 1st line. In addition, Vgon denotes a selection voltage level, and Vgoff denotes a non-selection voltage level. Similarly, G2 denotes a driving waveform of a scanning line that drives the 2nd line. Vcom indicates a driving waveform of an opposed electrode voltage signal line 212, and VcomP denotes a voltage level with positive polarity and VcomN denotes a voltage level with negative polarity. Vd indicates a tone voltage of a group of signal lines 213. When, with reference to the opposed electrode voltage Vcom, the tone voltage Vd is positioned on the negative polarity side, a voltage with negative polarity is applied to a pixel 215. Conversely, when the tone voltage Vd is positioned on the positive polarity side, a voltage with positive polarity is applied to the pixel 215.
The electric potential difference between the opposed electrode voltage Vcom and the tone voltage Vd causes the liquid crystal display to operate in such a manner that the luminance thereof is varied.
Additionally, in the conventional liquid crystal display illustrated in FIG. 8, there takes place a phenomenon that a voltage applied to a liquid crystal 217 causes a current leakage during a holding time-period, thus instabilizing a holding voltage of the liquid crystal 217. In order to prevent this phenomenon, in the liquid crystal display, there is commonly provided the compensation electrode 213. In addition, since a driving voltage for the compensation electrode 213 is also the same as a driving voltage waveform of the opposed electrode voltage Vcom, the description thereof will be omitted in the explanation in FIG. 9 and thereafter.
Next, referring to FIGS. 9 to 12, the explanation will be given below concerning problems in the conventional liquid crystal display. FIGS. 10A, 10B are diagrams for illustrating examples of displayed screens at the time of being displayed by the conventional liquid crystal display. FIG. 11 is a current path diagram for explaining causes of the picture quality deterioration in the conventional liquid crystal display. FIG. 12 is a driving waveform diagram for explaining the causes of the picture quality deterioration in the conventional liquid crystal display.
FIG. 10A is about an example of the following case: An intermediate gray is displayed all over the entire screen, and at the central portion, there are displayed a white rectangle, a light gray (gray the luminance (lightness) of which is higher as compared with that of the intermediate gray displayed all over the entire screen) rectangle, and a lighter gray (gray the luminance (lightness) of which is higher as compared with that of the above-mentioned light gray) rectangle. In FIG. 10A, there is illustrated the following phenomenon: Luminances of grays in display areas located on the right and the left sides of the three rectangles are lowered as compared with that of gray in the other display areas, and in addition, the respective amounts of the lowering in the luminances of the grays in the display areas located on the right and the left sides of the three types of rectangles are varied depending on the luminance levels of the three types of rectangles displayed at the central portion.
Similarly, FIG. 10B is about an example of the following case: Gray is displayed all over the entire screen, and at the central portion, there are displayed a black rectangle, a dark gray (gray the luminance (lightness) of which is lower as compared with that of the gray displayed all over the entire screen) rectangle, and a darker gray (gray the luminance (lightness) of which is lower as compared with that of the above-mentioned dark gray) rectangle. In FIG. 10B, there is illustrated the following phenomenon: Luminances of grays in display areas located on the right and the left sides of the three rectangles are heightened as compared with that of gray in the other display areas, and in addition, the respective amounts of the heightening in the luminances of the grays in the display areas located on the right and the left sides of the three types of rectangles are varied depending on the luminance levels of the three types of rectangles displayed at the central portion.
FIG. 11 illustrates electric current paths in the case where a voltage applied to each pixel on a line that a scanning line G1 selects has positive polarity, and indicates the manner in which the electric currents are concentrated onto the opposed electrode voltage signal line 212 and the compensation electrode 213.
In FIG. 12, a reference notation CL1 denotes a horizontal synchronization signal. The signal CL1 becomes effective at a ratio of one time during one horizontal time-period, and becomes a timing signal with which tone display data by the amount of one horizontal line are outputted by being transformed into a tone voltage. A notation M denotes the liquid crystal-applying voltage alternating signal. The signal M executes a control of converting the polarity of the opposed electrode voltage Vcom into negative polarity at the time of xe2x80x9cLowxe2x80x9d level and converting the polarity of the opposed electrode voltage Vcom into positive polarity at the time of xe2x80x9cHighxe2x80x9d level. A notation Vda denotes a tone voltage waveform that is applied to a portion of Da described in FIG. 10A and that is described by simplifying the portion of Da (i.e., described by reducing the number of the lines). A notation Vdb denotes a tone voltage waveform that is applied to a portion of Db described in FIG. 10A and that is described by simplifying the portion of Db (i.e., described by reducing the number of the lines).
Concerning the opposed electrode voltage Vcom, a full line (VcomA) indicates a waveform diagram of the opposed electrode voltage signal line 212 connected to an output terminal of a power supply circuit 205 illustrated in FIG. 8. Moreover, a dashed line (VcomB) indicates a waveform diagram inside a liquid crystal panel 206.
Next, referring to FIGS. 11, 12, the detailed explanation will be given below regarding the causes of the picture quality deterioration described in FIGS. 10A, 10B.
The luminances that the present conventional liquid crystal display displays are controlled by an effective voltage value Vdrms that is applied to the liquid crystal 217. The liquid crystal display is controlled so that, for example, when the effective voltage value is high, it displays a color of high luminance (white) and, when the effective voltage value is low, it displays a color of low luminance (black).
In FIG. 11, the opposed electrode voltage signal line 212 and the compensation electrode 213 are common to the respective pixels. Accordingly, in all the pixels, the electric currents are concentrated onto the opposed electrode voltage signal line 212 and the compensation electrode 213. When the electric currents are concentrated in this way, such loads as resistances (not illustrated) in the opposed electrode voltage signal line 212 and the compensation electrode 213 cause a voltage distortion to occur in the opposed electrode voltage and a compensation electrode voltage.
This voltage distortion has been found to be as illustrated in FIG. 12. Namely, during time-periods tH 1, tH 2 (both of which are the uppermost gray display areas of the rectangle region illustrated in FIG. 10A) and tH 9 (which is the lowermost gray display area of the rectangle region illustrated in FIG. 10A), the voltage level of the tone voltage remains constant (the tone voltage at the intermediate voltage level) in the horizontal direction as indicated by Vda, Vdb, and the opposed electrode voltage turns out to be expressed by VcomB. Meanwhile, during time-periods tH 3, tH 4 (both of which are the display areas of the white rectangle region illustrated in FIG. 10A), tH 5, tH 6 (both of which are the display areas of the lighter gray rectangle region illustrated in FIG. 10A) and tH 7, tH 8 (both of which are the display areas of the light gray rectangle region illustrated in FIG. 10A), Vda plays a role of executing the white rectangle display, the lighter gray rectangle display and the light gray rectangle display, which increases quantity of the electric current.
This condition increases quantity of the electric currents concentrated onto the opposed electrode voltage signal line 212 and the compensation electrode 213. This, further, prevents the opposed electrode voltage VcomB inside the liquid crystal panel 206 from attaining to the voltage level of the desired opposed electrode voltage VcomA. As the result, the opposed electrode voltage Vcom is lowered by the following amounts: xcex94Vcom 1 at the time of the white rectangle display, xcex94Vcom 2 at the time of the lighter gray rectangle display, and xcex94Vcom 3 at the time of the light gray rectangle display.
Also, in correspondence with the luminance levels of the three types of rectangles displayed at the central portion, the quantity of the electric currents concentrated onto the opposed electrode voltage signal line 212 and the compensation electrode 213 is also varied. Concretely speaking, the amount of the opposed electrode voltage Vcom that has been lowered as compared with the desired opposed electrode voltage VcomA is varied like +Vcom 1, xcex94Vcom 2, and xcex94Vcom 3. This results in a condition that effective voltage values, each of which has been lowered in the following way, are applied to the liquid crystal 217: With reference to the original effective voltage value Vdrms obtained during tH 1, tH 2 and tH 9, Vdrmsxe2x88x92xcex94Vcom 1 in the white rectangle display during tH 3, tH 4, Vdrmsxe2x88x92xcex94Vcom 2 in the lighter gray rectangle display during tH 5, tH 6, and Vdrmsxe2x88x92xcex94Vcom 3 in the light gray rectangle display during tH 7, tH 8.
The luminances that the liquid crystal display displays are controlled by the effective voltage value applied to the liquid crystal 217. Consequently, if the desired opposed electrode voltage fails to be obtained, the result is as follows: The display luminances are varied, and the luminances of grays in the display areas located on the right and the left sides of the three types of rectangle regions in the Db region described in FIG. 10A are lowered as compared with that of gray in the other display areas.
Meanwhile, as illustrated in FIG. 10B, there are provided the black rectangle region, the darker gray rectangle region and the dark gray rectangle region. This decreases quantity of the electric currents concentrated onto only the line region, thereby increasing the effective voltage value applied to the liquid crystal. Accordingly, there occurs the phenomenon that the luminances are heightened.
In this way, in the conventional liquid crystal display, the quantity of the electric currents concentrated onto the opposed electrode voltage signal line 212 and the compensation electrode 213 has been increased/decreased in correspondence with the display data. This has fluctuated the amount of the voltage distortion in the opposed electrode voltage and the compensation electrode voltage, thus causing the picture quality deterioration to occur.
The present invention has been made in view of the above-described problems. An object thereof is to provide a liquid crystal display that allows display of high picture quality to be embodied with the use of a low voltage driving circuit, and a driving method therefor.
It is an object of the present invention to provide a liquid crystal display that allows display of high picture quality to be embodied with the use of a low voltage driving circuit.
The present invention has been made in order to accomplish the above-described object. As the first mode thereof, there is provided a liquid crystal display including a liquid crystal panel having M units of pixels in the horizontal direction and N units of pixels in the vertical direction, each of the pixels including a switching element and a liquid crystal, a signal driving circuit for inputting display data and generating a tone voltage corresponding to the inputted display data so as to apply the tone voltage to one group of the pixels arranged in the horizontal direction and corresponding to the display data, and a scan driving circuit for selecting, in sequence, any one group of the pixels arranged in the vertical direction, the scan driving circuit, then, applying a selection voltage to the one group of the pixels arranged in the vertical direction and selected at that time and, meanwhile, applying a non-selection voltage to the other groups of the pixels arranged in the vertical direction and not selected at that time, the liquid crystal having, at one end thereof, an opposed electrode common to the respective pixels, wherein, when the selection voltage outputted by the scan driving circuit is applied to the switching element in each of the pixels, the tone voltage generated by the signal driving circuit is applied to the liquid crystal so that display luminance is controlled by an effective voltage value of the tone voltage toward the opposed electrode, and there are further included a circuit for detecting amount of data of the inputted display data and a power supply circuit for executing, in correspondence with the detected amount of the display data, an addition/subtraction control of a correction voltage value over an opposed electrode voltage value applied to the opposed electrode.
In the present invention, in order to accomplish the above-described object, there is provided a liquid crystal display apparatus or a driving method therefor, including a liquid crystal panel having M units of pixels in the horizontal direction and N units of pixels in the vertical direction, each of the pixels including a switching element and a liquid crystal, a signal driving circuit for inputting display data and generating a tone voltage corresponding to the inputted display data so as to apply the tone voltage to one group of the pixels arranged in the horizontal direction and corresponding to the display data, and a scan driving circuit for selecting, in sequence, any one group of the pixels arranged in the vertical direction, the scan driving circuit, then, applying a selection voltage to the one group of the pixels arranged in the vertical direction and selected at that time and, mean-while, applying a non-selection voltage to the other groups of the pixels arranged in the vertical direction and not selected at that time, the liquid crystal having, at one end thereof, an opposed electrode common to the respective pixels, wherein, when the selection voltage outputted by the scan driving circuit is applied to the switching element in each of the pixels, the tone voltage generated by the signal driving circuit is applied to the liquid crystal so that display luminance is controlled by an effective voltage value of the tone voltage toward the opposed electrode, and there are further included a member for detecting amount of data of the inputted display data and a voltage correcting member for executing a correction to the opposed electrode voltage value or an applying time-period thereof in correspondence with the detected amount of the display data and for each horizontal time-period.
Here, it is allowable that the voltage correcting member is configured to have, as an example, a circuit for generating a correction time-period controlling signal, the correction time-period controlling signal being generated for controlling the time-period during which the correction is executed to the opposed electrode voltage value in correspondence with the detected amount of the display data and for each horizontal time-period, and a circuit for executing an addition/subtraction control of a constant correction voltage value over the opposed electrode voltage value in correspondence with the correction time-period controlling signal generated and during only a time-period corresponding to the detected amount of the display data within each horizontal time-period. In this case, it is preferable that the circuit for generating the correction time-period controlling signal should include a data converting circuit including decoder circuits, a coincidence circuit, and a counter circuit. Also, it is preferable that the circuit for executing the addition/subtraction control of the correction voltage value should include an analog addition/subtraction circuit and an analog selecting circuit.
Also, it is allowable that the voltage correcting member is configured to have, as another example, a circuit for generating a correction time-period controlling signal for executing a correction to the opposed electrode voltage value during only a fixed time-period within one horizontal time-period, and a circuit for executing an addition/subtraction control of a correction voltage value over the opposed electrode voltage value in correspondence with the correction time-period controlling signal generated and during only a fixed time-period within one horizontal time-period. In this case, it is preferable that the circuit for generating the correction time-period controlling signal should include a counter circuit and a coincidence circuit. Also, it is preferable that the circuit for executing the addition/subtraction control of the correction voltage value should include a digital/analog converting circuit, an analog addition/subtraction circuit, and an analog selecting circuit.
Also, it is allowable that the voltage correcting member is configured to have, as still another example, a circuit for generating a correction time-period controlling signal, the correction time-period controlling signal being generated for controlling a time-period during which a correction is executed to the opposed electrode voltage value in correspondence with the detected amount of the display data and within one horizontal time-period, and a circuit for executing an addition/subtraction control of a correction voltage value over the opposed electrode voltage value during only a time-period corresponding to the correction time-period controlling signal generated, the correction voltage value corresponding to the detected amount of the display data. In this case, it is preferable that the circuit for generating the correction time-period controlling signal should include a data converting circuit including decoder circuits, a coincidence circuit, and a counter circuit. Also, it is preferable that the circuit for executing the addition/subtraction control of the correction voltage value should include a digital/analog converting circuit, an analog addition/subtraction circuit, and an analog selecting circuit.

Liquid crystal display and driving method therefor


A secure approval chain for runtime protection is disclosed. As an application or pod is developed in a pipeline, an approval engine ensures that the pod is approved by all approvers. The approval engine generates a deployment token that is added to the configuration data of the pod and that can be used at deployment to perform various security operations including pod verification, runtime environment control and enforcement, and pod or application verification.

CI/CD (Continuous Integration/Continuous Delivery or Deployment—referred to herein as a pipeline) is a method for continuously delivering applications. A pipeline is typically configured to automate the process of delivering software and allows multiple builds to be generated, tested, validated, and the like. A pipeline may include many steps or stages from building an application to the running the application in a runtime environment.
The pipeline may have many stages. By way of example only, applications are compiled, packaged, and scanned for threats (e.g., source and binaries) in a typical pipeline. The pipeline may also perform configuration checks, perform run-time vulnerability scans, deploy the application, and use data protection techniques.
However, there is often room for improvement in the pipeline. Stated differently, pipelines may have gaps with respect, by way of example only, to various stages including security and deployment. The problem faced by entities that use pipelines is how to identify and effectively resolve or remedy the gaps. In addition, the remedies should integrate into the pipeline efficiently.

Secure approval chain for runtime protection


The present invention relates generally to methods and devices for detecting, destroying and removing urinary calculi and other similar structures anywhere within an animal body, and more specifically to a method for locating such structures, fragmenting and vaporizing them and related detection and control schemes. The method for destruction and detection of urinary stones, calculi and similar structures includes the following steps: (a) providing a laser source suitable for performing laser lithotripsy; (b) initiating transmission of laser energy via a fiber optic laser delivery device so as to impinge upon a urinary stone or other structure and create a sparkle or emission of visible light; (c) transmitting the sparkle or emission of visible light reflected back through the fiber optic laser delivery device to a photomultiplier tube; (d) detecting an amplified signal corresponding to the sparkle or emission of visible light created upon fragmentation of the urinary stones, calculi or other obstruction; (e) creating a control signal for the power supply of the laser source; (f) controlling the laser source so as to continue to transmit laser energy through the fiber optic laser delivery device to a urinary stone or other structure; (g) repeating steps (c) through (f) until no sparkle or visible light emission is detected; and (h) terminating transmission of the laser energy.

Although the first useful lasers were developed in the 1960s, recent advances in laser and fiber optic delivery systems have greatly enhanced the use of this technology in the field of medicine. Today there are numerous types of laser systems designed for operation in a wide range of applications primarily related to surgical and other medical procedures.
Laser fibers are used in different ways, including incision, necrosis or killing of live tissue, excision or removal of tissue and structure, and cauterization of tissue. A very focused beam would provide the greatest amount of control during either operation. Cauterization and necrosis of living tissue is accomplished by coagulation, or more precisely with respect to the laser itself, by photocoagulation of contacted or penetrated tissue. In this process the laser beam causes the proteins in the contacted tissue to heat up rapidly and thermally denature. This essentially kills living tissue and seals blood vessels. The process has been likened to frying an egg. In practice, during an incision procedure cauterization of the incised tissue is likely to occur simultaneously. Thus, laser surgery is often characterized by an absence of bleeding during the surgery.
A common type of laser known as a CO2 laser delivers radiation with a wavelength of 10.64 microns. However, in order to focus or channel the radiated energy produced by a CO2 laser it is necessary to configure sets of mirrors in certain ways. These systems are typically large and expensive. With the mid-1980s FDA approval of the Nd:YAG type laser delivering electromagnetic energy at a wavelength of 1.064 microns, it became possible to generate and focus the laser radiation through a silica core optical fiber. Recently, the Holmium: Yttrium-silver-garnet (Ho:YAG) laser has become an important tool in the hospital and clinic due to it's relatively low cost and wide range of applications suitable for it's use.
Lasers, and in particular Ho:YAG lasers, have been used for a variety of purposes in urology. Such procedures include performing partial or full nephrectomies (removal of one or both of the kidneys), laser-assisted trans-urethral resections of the prostate (a TURP is a procedure required for managing benign prostatic hyperplasia or BPH--a frequent condition caused by swelling of the prostate), treatment of superficial bladder carcinomas or tumors, and other laparascopic procedures.
Numerous modalities exist for the destruction of urinary tract calculi, aside from lasers. These include electrohydraulic probes, ultrasonic probes, electromechanical impactors, and the lithoclast (a compressed air-driven metal pin). Focused shock waves can be delivered from an external source in a procedure known as extracorporeal shock wave lithotripsy or ESWL.
Destruction of gall stones and urinary stones with lasers has been studied as early as 1979. The following is a brief survey of various types of lasers useful for such procedures:
Excimer lasers (xenon, fluoride and xenon chloride) produce shorter wavelength laser radiation. Standard excimer lasers have a pulse duration of 10 nanoseconds which is too short for easy transmission through fibers. Longer pulsed excimer lasers (up to 100 nanoseconds) can be transmitted through optical fibers more easily. Fragmentation of calculi is efficient but one drawback is that both tissue and stone absorb excimer wavelengths strongly, without any beneficial selectivity. The laser is also useful for tissue ablation.
Pulsed dye lasers operate efficiently at a pulse duration of 1 microsecond, which is ideal for stone fragmentation. These lasers emit at wavelengths from the ultraviolet to the red, according to the dye chosen. The maximum differential absorption between stone and ureter tissue occurs at 504 nanometer and this wavelength is, therefore, useful.
Alexandrite lasers are solid-state lasers which emit at 720 nanometer. The pulse duration is typically 10 to 100 nanoseconds, the longer durations more efficiently transmitted. The disadvantage of using the lower durations, with attending high peak pulse power, is that the fiber becomes eroded rapidly during fragmentation of a stone. The longer pulsed alexandrite lasers transmit better but fragmentation of certain calculi is still not highly efficient due to the unfavorable absorption at these wavelengths.
Titanium sapphire lasers are semiconductor lasers, and therefore have the potential to be relatively smaller and more economical than others. They emit at approximately 850 nanometer. Between 3 and 13 microseconds, shorter pulse durations are favored requiring pulse energies of 100 to 200 mJoules to fragment calculi. The action on pale calculi is relatively inefficient and the laser has a variable effect on calculi as the stones shrink and change size and composition during their destruction.
Continuous wave Nd:YAG lasers, though widely used in numerous medical and other applications, should never be used to fragment urinary calculi pulsing the laser will allow fragmentation however. The 100 microsecond laser has been described as having the capability of fragmenting uric acid and gallstones, but not pale calculi. The 10 microsecond Nd:YAG laser has been used at pulse energies of 30 mJoules via 400 micron core fibers to fragment calculi. The high peak power allows fragmentation in spite of poor absorption. At these low-pulse energies, the fiber transmission is feasible. However, the distal end of the fiber is at risk of destruction should it touch the stone. Therefore, solutions include shaping a lens at the distal end of the fiber and placing a metal cap on the end of the fiber which forms a type of shock wave.
The Ho:YAG laser produces light at a wavelength of 2,000 to 2,100 nanometer (2.0 to 2.1 microns), depending upon the precise formulation of the holmium rod, in a pulsed fashion. These wavelengths are well absorbed by water, and thus their use for stone fragmentation is not obvious. Of the devices available, the energy of each pulse and the frequency can be varied. The energy levels typically used are between 0.2 and 2.8 Joules per pulse and the frequency is typically varied between 5 and 20 Hertz. Typical pulse durations are 350 microseconds. The energy produced can be transmitted along suitable silica-based optical fibers, typically ranging in core size between 250 and 750 microns. One drawback of the Ho:YAG laser is that the regimen described has an equally powerful effect on tissue, such as the ureter, and damage can be expected should the laser fiber touch it during delivery.
Endoscopes of various designs are widely used for ureteroscopy. Rigid instruments are generally employed for the distal ureter and may be advanced into the mid- and proxima-ureters in some patients. Actively deflectable, flexible ureteroscopes can be used in the proximal portions of the ureter and the intrarenal collecting system to access most areas. A working channel of at least 2.2 French is recommended for placement of the smaller fibers, such as the 200 micron diameter fiber..
The construction of optical fibers used in surgical procedures is fairly simple. A quartz, plastic or silicone cladding is used to constrain the laser light to the quartz core. Theoretically, only a few of the entering photons are directed straight down the axis of the fiber. Transmission of the radiant beam is possible since the rest of the photons are constrained to the core of the fiber due to internal reflectance by the quartz cladding interface. Very few photons escape the fiber. The technology related to the use of silica core fibers in medical lasers is well known, e.g. B. P. McCann, Photonics Spectra, May 1990, pp 127-136.

Method of detection and destruction of urinary calculi and similar structures


Light source modules are disclosed, which include an emitter having a light-emitting surface and a pyramid collector mounted onto the emitter over the emitting surface. Also disclosed are illumination systems, including a plurality of light source modules, each light source module comprising an emitter having a light-emitting surface and a pyramid collector mounted onto the emitter over the emitting surface. The illumination systems further include an illumination target and a system of optical elements disposed between the at least one light source module and the illumination target.

Illumination systems have a variety of applications, including projection displays, backlights for liquid crystal displays (LCDs) and others. Projection systems usually include a source of light, illumination optics, an image-forming device, projection optics and a projection screen. The illumination optics collect light from a light source and direct it to one or more image-forming devices in a predetermined manner. The image-forming device(s), controlled by an electronically conditioned and processed digital video signal, produces an image corresponding to the video signal. Projection optics then magnify the image and project it onto the projection screen. White light sources, such as arc lamps, in conjunction with color wheels have been and still are predominantly used as light sources for projection display systems. However, recently, light emitting diodes (LEDs) were introduced as an alternative. Some advantages of LED light sources include longer lifetime, higher efficiency and superior thermal characteristics.
One example of an image-forming device frequently used in digital light processing systems is a digital micro-mirror device (DMD). The main feature of a DMD is a rectangular array of rotatable micro-mirrors. The tilt of each mirror is independently controlled by the data loaded into the memory cell associated with each mirror, to steer reflected light and spatially map a pixel of video data to a pixel on a projection screen. Light reflected by a mirror in an ON state passes through the projection optics and is projected onto the screen to create a bright field. On the other hand, light reflected by a mirror in an OFF state misses the projection optics, which results in a dark field. A color image also may be produced using a DMD, e.g., utilizing color sequencing, or, alternatively, using three DMDs, one for each primary color.
Other examples of image-forming devices include liquid crystal panels, such as a liquid crystal on silicon device (LCOS), which are typically rectangular. In liquid crystal panels, the alignment of the liquid crystal material is controlled incrementally (pixel-to-pixel) according to the data corresponding to a video signal. Depending on the alignment of the liquid crystal material, polarization of the incident light may be altered by the liquid crystal structure. Thus, with appropriate use of polarizers or polarizing beam splitters, dark and light regions may be created, which correspond to the input video data. Color images have been formed using liquid crystal panels in the manner similar to the DMDs.
Performance of optical systems, such as illumination optics of a projection system, may be characterized by a number of parameters, one of them being etendue. The etendue, ε, may be calculated using the following formula:ε=A*Ω≅π*A*sin2θ=π*A*NA2where Ω is the solid angle of emission or acceptance (in steradians); A is the area of the receiver or emitter, θ is the emission or acceptance angle, and NA is the numerical aperture. If the etendue of a certain element of an optical system is less than the etendue of an upstream optical element, the mismatch may result in loss of light, which reduces the efficiency of the optical system. Thus, performance of an optical system is usually limited by the element that has the smallest etendue. Techniques typically employed to decrease etendue degradation in an optical system include increasing the efficacy of the system (lm/w), decreasing the source size, decreasing the beam solid angle, and avoiding the introduction of additional aperture stops.
Traditional optics used in illumination systems have included various configurations, but their off-axis performance has been satisfactory only within narrowly tailored ranges. In addition, optics in traditional illumination systems have exhibited insufficient collection characteristics. In particular, if a significant portion of a light source's output emerges at angles that are far from the optical axis, which is the case for most LEDs, conventional illumination systems fail to capture a substantial portion of such light. In addition, although some traditional reflective collimators have acceptable collection characteristics, for example, elliptical and parabolic reflectors, such reflectors are usually characterized by rotationally symmetrical bias. Such a bias generally results in the rounding of the resultant image, as well as in lack of overall correspondence between a point on the light source and a point on the target plane, thus causing loss of order and degradation of etendue. These and other shortcomings prompted complicated designs of optical elements and systems, which involved, e.g., utilization of complicated aspheric surfaces and complex combinations of numerous elements.

Reshaping light source modules and illumination systems using the same


An electric potential fixing apparatus of the present invention is an electric potential fixing apparatus that is connected to a connection line (17) between two capacitances, the first capacitance (14) and the second capacitance (15) that is directly connected to the first capacitance, includes the first high resistance (3), the second high resistance (4) that is connected directly to the first high resistance, a voltage dividing unit that outputs electric potential divided by the first high resistance and the second high resistance to the output terminal, the third capacitance (8) that is connected in parallel to at least either of the first high resistance and the second high resistance, and a voltage supply unit (1) operable to maintain constantly electric potential of the connection line between the two capacitances (14) and (15), holding combined total electric charge quantity of the first capacitance and the second capacitance, and the output terminal of the voltage supply unit is connected to a signal line between the two capacitances.

Conventionally, a capacitance measurement apparatus that measures a capacitance value of a capacitive sensor such as a capacitor microphone whose electrostatic capacitance changes in response to received physical quantity (acceleration, pressure, gas, light, sound wave and so on) is known. FIG. 1 shows a conventional capacitance measurement apparatus 100. As shown in FIG. 1, the conventional capacitance measurement apparatus 100 includes an operational amplifier OP, an AC voltage generation apparatus OSC, a capacitive sensor Cs, resistance Rf that is feedback impedance. The AC voltage generation apparatus OSC generates an operation signal Vin that is applied to the capacitive sensor Cs at the time of measuring the capacitance. The capacitive sensor Cs and an inversion input terminal of the operational amplifier OP are connected by the signal line L. The resistance Rf is connected between the signal line L and the operational amplifier OP. Additionally, the capacitive sensor Cs is connected between the inversion input terminal of the operational amplifier OP and the AC voltage generation apparatus OSC. One terminal of the AC voltage generation apparatus OSC is connected to standard electric potential.
As for an operation of the conventional capacitance measurement apparatus 100 shown in FIG. 1, when voltage Vin from the AC voltage generation apparatus OSC is supplied, alternating current flows to the capacitive sensor Cs. In this case, since input impedance of the operational amplifier OP is ideally infinite, all the current that flows to the capacitive sensor Cs flows to the resistance Rf.
Output of the capacitance measurement apparatus Vout can be derived from the following method.
When the amplitude of the operation signal is V, the angular velocity of the operation signal is ωin, the standard capacitance of the capacitive sensor is Cd, the amplitude of change capacitance of the capacitive sensor Cs is C, and the angular velocity of capacitance change is ωc, the operation signal Vin and the capacitance of the capacitive sensor Cs can be represented byVin=V sin ωint  (1)Cs=Cd+C sin ωct  (2)
Since the current Is that flows through the capacitive sensor can be represented byIs=d(CsVin)/dt  (3)and the output Vout can be represented byVout=−IsRf  (4),by the expressions (1) through (4)Vout=−Rf{(Cd+C·sin ωct)·ωin·cos ωint+C·ωc·cos ωct·sin ωint}V  (5)is derived.
As is known from this expression (5), the output Vout has a term whose coefficient is the angular velocity of the capacitance change ωc. This means that in the case of the feedback impedance being the resistance, when the capacitance of the capacitive sensor changes at the frequency ωc, the output Vout that depends on the frequency ωc is outputted (the output Vout has frequency dependence). Consequently, in the case of the feedback impedance being the resistance, a processing circuit that does not have a frequency characteristic in the subsequent stage must be configured, and therefore there is a problem that the size of the circuit becomes large.
There, technology that the feedback impedance is configured not by the resistance but by the capacitance is proposed. FIG. 2 shows the capacitance measurement apparatus 101 whose feedback impedance is configured by the capacitance Cf. In this case, since the electric charge stored in the capacitive sensor Cs and that stored in the feedback capacitance Cf. are equal,−Cf·Vout=Cs·Vin  (6)holds, and therefore the output Vout can be represented byVout=−(Cd+C sin ωct)/Cf·V sin ωin  (7)
As is known from this expression, output voltage Vout does not include a term that is proportional to the angular velocity ωc. This is because the electric charge of the signal line L that is connected to two capacitances is maintained constantly when the feedback impedance is configured by the capacitance.
As described above, since the term that is proportional to frequency of capacitance change dose not appear in circuit output, there is no need to set up a processing circuit newly in the subsequent stage. As a result, it is possible to prevent the size of the circuit from becoming large.
However, in the case of configuring the feedback impedance by the capacitance Cf, the signal line L that connects Cf and the capacitive sensor becomes floating state electrically. For this reason, the electric potential of the signal line L becomes unstable and abnormality in a circuit operation that the circuit output is saturated with the power voltage may occur.
To prevent such a circuit abnormality, as shown in FIG. 2, it is conceivable to fix the electric potential of the signal line L by connecting resistance Rg between the signal line L and the ground.
However, in the case of fixing the electric potential by the resistance Rg, at the time of measuring the capacitance, there may be a case that potential difference in the both terminals of the resistance Rg is generated and that current flows through the resistance Rg. In that case, since the amount of electric charge varies in quantity, there is a problem that the sensibility of the capacitance measurement apparatus 101 decreases.
Consequently, it is desirable to propose a means to fix the electric potential of the signal line L without changing the electric charge quantity of the signal line L.
Additionally, when the standard capacitance Cd of the capacitive sensor Cs is very large compared with the capacitance change C, there is a problem that the capacitance change is not fully reflected in the output Vout.
Consequently, even if the standard capacitance Cd is very large compared with the capacitance change C, a circuit with satisfactory sensibility is desirable.
The present invention is done to solve the above-mentioned problems and the object of the present invention is to provide a capacitance measurement apparatus equipped with an electric potential fixing means for fixing the electric potential level of the signal line without changing the electric charge quantity of the signal line of the capacitance measurement apparatus and a standard capacitance cancel means for canceling the effect that the standard (fixed) capacitance of the capacitive sensor has on the circuit output.

Potential fixing device and potential fixing method


A directory enabled network element, which in one embodiment, is a network device that has an element that enables querying, accessing, and updating directory information that is managed by a directory service of a network. An application programming interface (API) is configured to receive directory services requests from application programs (APs) and provide the directory services requests to the directory enabling element. A locator service is accessible using the API and configured to locate servers that provide the directory services. A bind service in the directory enabling element is coupled to a security protocol. An event service is configured to receive registration of an event and an associated action from an AP, notify the AP when the event occurs, and execute the associated responsive action. The network device can thereby automatically authenticate itself to a directory service.

—Computer Networks
A computer network typically comprises a plurality of interconnected entities ("network elements") that transmit ("source") or receive ("sink") data frames. A common type of computer network is a local area network ("LAN") that generally comprises a privately owned network within a single building or campus. LANs employ a data communication protocol (LAN standard) such as Ethernet, FDDI, or Token Ring, that defines the functions performed by the data link and physical layers of a communications architecture (i.e., a protocol stack), such as the Open Systems Interconnection (OSI) Reference Model. In many instances, multiple LANs may be interconnected by point-to-point links, microwave transceivers, satellite hookups, etc., to form a wide area network ("WAN"), metropolitan area network ("MAN") or Intranet. These internetworks may be coupled through one or more gateways to the global, packet-switched internetwork known as the Internet.
Each network entity preferably includes network communication software, which may operate in accordance with Transport Control Protocol/Internet Protocol (TCP/IP) or some other suitable protocol. A protocol generally consists of a set of rules defining how entities interact with each other. In particular, TCP/IP defines a series of communication layers, including a transport layer and a network layer. At the transport layer, TCP/IP includes both the User Data Protocol (UDP), which is a connectionless transport protocol, and TCP which is a reliable, connection-oriented transport protocol. When a process at one network entity (source) wishes to communicate with another entity, it formulates one or more messages and passes them to the upper layer of the TCP/IP communication stack. These messages are passed down through each layer of the stack where they are encapsulated into packets and frames. Each layer also adds information in the form of a header to the messages. The frames are then transmitted over the network links as bits. At the destination entity, the bits are re-assembled and passed up the layers of the destination entity's communication stack. At each layer, the corresponding message headers are also stripped off, thereby recovering the original message which is handed to the receiving process.
One or more intermediate network devices are often used to couple LANs together and allow the corresponding entities to exchange information. For example, a bridge may be used to provide a "bridging" function between two or more LANs. Alternatively, a switch may be utilized to provide a "switching" function for transferring information, such as data frames or packets, among entities of a computer network. Typically, the switch is a computer having a plurality of ports (i.e., logical network interfaces ("LI" or "interfaces)) that couple the switch to several LANs and to other switches. The switching function includes receiving data frames at a source port and transferring them to at least one destination port for receipt by another entity. Switches may operate at various levels of the communication stack. For example, a switch may operate at Layer 2 which, in the OSI Reference Model, is called the data link layer, and includes the Logical Link Control (LLC) and Media Access Control (MAC) sub-layers.
Other intermediate devices, commonly known as routers, may operate at higher communication layers, such as Layer 3, which, in TCP/IP networks, corresponds to the Internet Protocol (IP) layer. IP data packets include a corresponding header which contains an IP source address and an IP destination address. Routers or Layer 3 switches may re-assemble or convert received data frames from one LAN standard (e.g., Ethernet) to another (e.g., Token Ring). Thus, Layer 3 devices are often used to interconnect dissimilar subnetworks. Some Layer 3 intermediate network devices may also examine the transport layer headers of received messages to identify the corresponding TCP or UDP port numbers being utilized by the corresponding network entities. Many applications are assigned specific, fixed TCP and/or UDP port numbers in accordance with Request For Comments (RFC) 1700. For example, TCP/UDP port number 80 corresponds to the Hypertext Transport Protocol (HTTP), while port number 21 corresponds to File Transfer Protocol (FTP) service.
—Network Element Intelligence
A significant drawback of current network technology is that routers primarily store the information needed to set other network elements as needed to carry out network services ("provisioning"). Workstations or PCs that carry out network management functions typically have information useful in determining how to interconnect network elements ("configuration"), and network service policies, but do not have the knowledge of how to carry out these higher level policies onto a specific router with a given NOS. Further, such devices normally do not have a means to deliver such policies onto a router in such a way that router understands exactly how to integrate the policies into its internal software structure in order to provision the required network services for that network element.
A related drawback is that provisioning is typically carried out using a complicated, arcane, command-line interface (CLI) that is supported by routers. A technician enters one or more CLI commands into a router or other device using a terminal interface. This is called manual CLI provisioning.
Second generation network elements often support Simple Network Management Protocol (SNMP) and can be provisioned using SNMP messages and Management Information Base (MIB) variable values. However, many thousands of non-SNMP devices are currently used in existing networks. For these devices, there is no adequate way to carry out provisioning changes, and in particular, there is no way to carry out provisioning changes in a secure way because the CLI typically receives a non-encrypted user name and password ("cleartext"). Further, some large enterprises do not believe that SNMP version 1 is secure enough for use in mission-critical networks. SNMP version 2 included better security provisions, but never became a standard. SNMP version 3 also includes better security provisions, but is recently proposed and not currently a standard.
—Directory Services
Directory services, separate from network elements, are now used in networks. A network element may contact a directory server that forms part of a directory service, using an agreed-upon protocol, to locate other network elements, clients and servers in a network. Directory services are described generally in publications, including, for example, R. Orfali et al., "Client-Server Survival Guide" (New York: John Wiley & Sons, 3d ed., 1999), at pp. 131–139.
The first generation of directory services, such as Novell Directory Service (NDS), conformed to the ITU X.500 standard and provided access to static information. Rapid network growth has created the need for more robust, scalable and secure directory services. Second generation directory services, such as Microsoft Active Directory, Netscape Directory, and others that conform to Lightweight Directory Access Protocol (LDAP), offer more powerful information and a schema that models the entire network. LDAP is defined in public documents such as RFC 1777, RFC 1823, and RFC 2251 through RFC 2256, inclusive. Microsoft Active Directory is under development and not yet commercially released. It is an anticipated component of Microsoft Windows 2000. Netscape Directory has been the predominant directory server for UNIX platforms. NDS has recently improved its compliance with standards, as well as its security services, which use Public Key Infrastructure (PKI). Kerberos and PKI are the most significant standards-based, industry-backed security technologies available today.
Active Directory uses Kerberos credentials to accomplish authentication of users and processes. Using Active Directory, a network element can authenticate itself to the directory before the network element can communicate with the directory. This ensures that only recognized network elements can obtain sensitive directory information, thereby helping to protect the network against unauthorized use or attack. Further, an authenticated network element is logged into the directory as a trusted client, and can do more than a non-trusted or non-authenticated client. For example, a trusted client can access policies in the directory; associate policies with devices; and apply more sophisticated configuration information.
On the other hand, PKI (public key infrastructure) enables users of unsecured public networks such as the Internet to securely and privately exchange data and monetary value through the use of a public and a private cryptographic key pair that is obtained and shared through a trusted authority. The public key infrastructure provides for digital certificates that can identify individuals or organizations and directory services that can store and, when necessary, revoke them. Although the components of a PKI are generally understood, a number of different vendor approaches and services are emerging. Meanwhile, an Internet standard for PKI is under consideration.
The public key infrastructure assumes the use of public key cryptography, which is the most common method on the Internet for authenticating a message sender or encrypting and decrypting a message. Traditional cryptography has usually involved the creation and sharing of a secret key for the encryption and decryption of messages. This secret or private key system has the significant flaw that if the key is discovered or intercepted by someone else, messages can easily be decrypted. For this reason, a combination of public key cryptography and the public key infrastructure is the preferred approach on the Internet.
A public key infrastructure consists of:
—A certificate authority (CA) that issues and verifies digital certificates. A certificate includes the public key or information about the public key.
—A registration authority (RA) that acts as the verifier for the certificate authority before a digital certificate is issued to a requester.
—One or more directories where the certificates (with their public keys) are held (usually in an ITU X.500 standard directory).
—A certificate management system.
However, in current approaches, routers, switches, gateways, load balancers, and other elements of a conventional packet-switched network cannot automatically authenticate themselves to the directory. A separate service is required to facilitate such authentication. Thus, there is a need to provide a way for a router or other network element to authenticate itself to the directory automatically, for example, when the network element is powered up.
There is also a specific need for a way to carry out authentication of a router or other network element to the directory using Kerberos credentials rather than CLI passwords that are communicated in cleartext.
The widely distributed nature of directory services is extremely useful for geographically and logically distributing policies and configurations. A drawback of this approach, however, is that there is no inherent mechanism whereby a router or other network element can locate the nearest directory server. There is a need for a location service with which a network element can find the nearest directory server.
Another drawback of current directory services is that they lack an event notification mechanism, unlike typical database servers that do have event services. There is a need for a standalone event notification service for signaling network elements for some network services such as provisioning requests.
More broadly, there is a need in this field for an improved method or mechanism that enables network elements such as routers, switches, gateways and hubs to query, access, and update data of a second generation directory service in a secured fashion.
There is a particular need for a system that can use the IETF Policy Framework to model various policies of network services, describing the behavior of both hardware and software elements in network elements in the network and their relationships in a set of Directory Schema, and sending out provisioning requests from users to network element through event notification. There is also a need for Directory-enabled software components in a network element (Agents) that can obtain provision policy data from the Directory by event notification, interrupt the policy data, and apply the policy internally within the NOS to change the behavior of a network element.
There is also a need for a network management application that understands the semantics of network elements and that can provision network elements by directly sending configuration commands into the network elements through use of event notification.


Systems and methods for notifying a user that a restrained party is within a specified distance of a specified location are disclosed. A method according to the invention includes storing identity data that represents an identity of a restrained party, location data that represents a specified location, and distance data that represents a specified distance from the specified location. A restrained party location signal that represents a current location of the restrained party is received. From the location data and the distance data, a determination is made as to whether the current location of the restrained party is within the specified distance from the specified location. If the current location of the restrained party is within the specified distance from the specified location, an alert is transmitted to one or more contacts.

Unfortunately, it is sometimes necessary for a person to obtain a restraining order against another person. A restraining order typically prohibits a restrained party from being within a certain specified distance from a certain specified location related to the restraining party. For example, a restraining order might prohibit the restrained party from being within a certain distance from the restraining party's house or place of business, or from being with a certain distance from the restraining party regardless of where the restraining party is located.
It is possible, however, for the restrained party to violate the restraining order (i.e., to be within the specified distance from the specified location) without the restraining party's knowledge. For example, the restrained party might be waiting outside the restraining party's house while the restraining party sleeps. It is also possible for the restrained party and the restraining party to be in the same place, such as a shopping mall, for example, by pure coincidence, without either knowing that the other is there.
Additionally, even if the restraining party is aware that the restrained party is in violation of the restraining order, the restraining party must take affirmative action to notify authorities, such as the police or the courts. The time that it takes for the restraining party to notify authorities, however, might be enough time for the restrained party to cause harm to the restraining party, or to escape, leaving the restraining party with no proof that the restrained party violated the restraining order.
It would be advantageous, therefore, if there were available systems and methods for providing notification that a restrained party is within a specified distance of a specified location. Such systems and methods would be particularly advantageous if they provided for notification of the restraining party as well as other third parties, such as authorities or emergency services, for example.

Systems and methods for providing notification of a location of a restrained party

BellSouth Intellectual Property Corporation