JP2003215538A - Capacitive coupling driving method, liquid crystal display device, program, and medium - Google Patents

Abstract

(57) [Summary] [Problem] There has been difficulty in designing a liquid crystal display device. SOLUTION: The capacitive coupling driving method of the present invention is a capacitive coupling driving method for a liquid crystal display device of a post-stage connection type, wherein when a voltage is applied to a signal electrode using polarity inversion, an active element is turned on. A scanning signal using three types of voltage values, ie, an on-voltage value VGH for turning off the active element, an off-voltage value VGL for turning off the active element, and a correction voltage value VE for correcting the potential of the pixel electrode, is applied to the scanning electrode. During the period in which the voltage value of the scanning signal shifts from the off-voltage value VGL to the on-voltage value VGH,
(1) a frame to which the compensation voltage value VE is applied;
This is a capacitive coupling driving method that alternately generates a frame to which an on-voltage value VGH is applied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capacitive coupling driving method, a liquid crystal display device, a program, and a medium.

[0002]

2. Description of the Related Art Conventionally, in a capacitive coupling driving method capable of reducing flicker and an afterimage, in order to reduce cost and power consumption, the number of types of voltage required for a scanning signal applied to a scanning electrode has been reduced.

In such a case, the correction amount of the image signal by the correction voltage is different for each frame between the positive polarity and the negative polarity, or the punch-through potential amount generated when the active element is turned off is different for each polarity. Different to

Therefore, the conventional capacitive coupling driving method (conventional example 1) in which the correction amount of the image signal by the correction voltage is inverted for each frame, which is different in the positive polarity and the negative polarity,
The conventional capacitive coupling driving method (conventional example 2) in which the amount of punch-through potential generated when the active element is turned off differs depending on the polarity will be described in order.

First, a conventional capacitive coupling driving method (conventional example 1) in an active matrix type liquid crystal display device will be described.

FIG. 3 shows an equivalent circuit of an active matrix type liquid crystal array in a so-called front stage connection type capacitive coupling drive system in which the pixel electrode potential is corrected by changing the voltage of the front stage scan electrode in the scanning direction of the scan electrode. It is shown.

In FIG. 3, 5 is one of a plurality of signal electrodes, 50 and 51 are continuous scanning electrodes, and 10 and 11
Is an active element connected to the signal electrode 5 and the scanning electrodes 50 and 51, 60 and 61 are pixel electrodes connected to the signal electrode 5 via the active elements 10 and 11, and 20 and 21 are pixel electrodes. Parasitic capacitances 60 and 61 and the scanning electrodes 50 and 51, 30, 31 are equivalent capacitances of liquid crystal pixels, 40 and 41 are storage capacitances for accumulating and correcting the pixel potential, and 70 is a pixel. A common electrode facing the electrode and connected to the liquid crystal pixel is shown.

FIG. 4 shows a pre-stage connection type capacitive coupling driving method (conventional example 1) in the liquid crystal array configured as described above.
This will be described using the drive waveform of.

FIG. 4 shows scan electrode 2n-1 and scan electrode 2n.
2 shows the voltage waveform of the pixel electrode 60, the voltage waveform of the signal electrode using polarity inversion with respect to the scan electrode 2n, and the voltage waveform of the pixel electrode 60.

First, the active element 10 connected by the voltage VGH of the scan electrode 2n is turned on to turn on the pixel electrode 60.
The image signal potential from the signal electrode is supplied to. Next, the active element 10 is turned off by the voltage VGL of the scan electrode 2n. At this time, the stored capacitance of the pixel electrode is lowered by the parasitic capacitance 20, and so-called punch-through occurs.

Subsequently, the potential of the scan electrode 2n-1 is set to VE.
By changing from VGL to VGL, the potential of the pixel electrode 60 is raised and a so-called correction potential is added. The potential difference between the pixel potential in this state and the potential of the common electrode 70 is applied to the liquid crystal pixel for about one frame.

In the next frame, that is, in the odd frame period, the voltage waveform of the scan electrode 2n is the same as the waveform of the scan electrode 2n-1 in the previous frame, while
The voltage waveform of the scan electrode 2n-1 is the same as that of the scan electrode 2 of the previous frame.
It is similar to the voltage waveform of n. This is because the voltage waveform of the scan electrode 2n further corrects the potential of the pixel electrode connected to the scan electrode 2n + 1 in the subsequent stage. Scan electrode 2n-1
The same applies to the voltage waveform of. Therefore,
In the odd-numbered frame, the same penetration as in the even-numbered frame occurs in the pixel electrode 60 connected to the scan electrode 2n, but no correction potential is applied.

Next, another capacitive coupling drive method using drive waveforms in another conventional example (conventional example 2) will be described.

FIG. 5 shows another example of the capacitive coupling drive waveform of the pre-connection type in the liquid crystal array shown in FIG. 3, in which the voltage waveforms of the scan electrode 2n-1 and the scan electrode 2n and the scan electrode 2n are shown.
The voltage waveform of the signal electrode and the voltage waveform of the pixel electrode 60 using the polarity reversal with respect to are shown.

First, in the even-numbered frame period in FIG. 5, similarly to the drive waveform shown in FIG. 4, for the pixel electrode 60 connected to the scan electrode 2n, the voltage VE of the scan electrode 2n-1 changes from VGL. Therefore, the potential is corrected.

After that, the voltage waveform of the scan electrode 2n drops from the voltage VGL to VE for the potential correction of the pixel electrode connected to the scan electrode 2n + 1 in the subsequent stage. As a result, as a voltage change of the scan electrode 2n, from VGH to VGL, V
Penetration occurs in two stages from GL to VE.

In the next odd frame, the scan electrode 2
By the change from the voltage VGL of n-1 to VE, the same amount of potential correction is performed in the opposite direction to the case of the even frame. Regarding penetration, from the voltage VGH of the scan electrode 2n to VE,
The change from VE to VGL results in VGH to V
Penetration occurs due to the change to GL.

[0018]

However, in the drive waveform (conventional example 1) shown in FIG. 4, the penetration amount in each frame is the same, but the potential correction amount of the pixel electrode is different. In the drive waveform (conventional example 2) shown in FIG. 5, the pixel electrode potential correction amount in each frame is the same, but the penetration amount is different.

Therefore, the voltage VCO applied to the common electrode is
It is necessary to adjust M so that the total amount of charges applied to the liquid crystal pixel becomes equal (that is, V is designed in advance).
In order to adjust the COM level, it is necessary to provide a VCOM variable means such as a variable resistor or an electronic volume). As a result, the cost of parts and the circuit mounting area have increased. Also, VCOM
Since the set level must be determined by the total amount of charge applied to the liquid crystal pixel, the voltage level design is complicated.

The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to provide a capacitive coupling driving method, a liquid crystal display device, a program, and a medium, which are easier to design in a liquid crystal display device. It is a thing.

[0021]

[Means for Solving the Problems] The first invention (Claim 1)
Corresponds to a plurality of active elements respectively connected to a plurality of signal electrodes and a plurality of scan electrodes arranged in a matrix, a plurality of pixels respectively connected to the active elements via pixel electrodes, A capacitive coupling driving method of a liquid crystal display device of a latter stage connection type, comprising: a common electrode facing a plurality of pixel electrodes with a plurality of pixels sandwiched therebetween, wherein voltage application to the signal electrode utilizes polarity inversion. When performed, three types of voltages, an on-voltage value VGH for turning on the active element, an off-voltage value VGL for turning off the active element, and a correction voltage value VE for correcting the potential of the pixel electrode. Applying a scan signal using a value to the scan electrode, wherein the voltage value of the scan signal shifts from the off voltage value VGL to the on voltage value VGH. In the period of order, which is (1) the frame compensation voltage value VE is applied, (2) the on produce a frame voltage VGH is applied alternately capacitive coupling driving method.

According to a second aspect of the present invention (corresponding to claim 2), VGH-VGL = VGL-V is provided between the ON voltage value VGH, the OFF voltage value VGL, and the compensation voltage value VE.
It is the capacitive coupling driving method according to the first aspect of the present invention in which the relationship of E is established.

In the third aspect of the present invention (corresponding to claim 3), the voltage value of the scanning signal directly shifts from the on-voltage value VGH to the off-voltage value VGL in each frame. It is a capacitive coupling drive method of the present invention.

According to a fourth aspect of the present invention (corresponding to claim 4), a plurality of active elements respectively connected to a plurality of signal electrodes and a plurality of scan electrodes arranged in a matrix,
A post-connection liquid crystal display device comprising a plurality of pixels each connected to the active element via a pixel electrode, and a common electrode facing the plurality of pixel electrodes with the plurality of pixels interposed therebetween, When the voltage application to the signal electrode is performed by using polarity inversion, an on-voltage value VGH for turning on the active element and an off-voltage for turning off the active element using a capacitive coupling driving method. A scan signal using three types of voltage values, a value VGL and a correction voltage value VE for correcting the potential of the pixel electrode, is applied to the scan electrode, and the voltage value of the scan signal is changed from the off-voltage value VGL. In the period for shifting to the ON voltage value VGH, (1) a frame to which the compensation voltage value VE is applied, and (2) a frame to which the ON voltage value VGH is applied. A liquid crystal display device produced alternately.

According to a fifth aspect of the present invention (corresponding to claim 5), in the capacitive coupling driving method according to the first aspect of the present invention, when the voltage application to the signal electrode is performed by utilizing polarity inversion, the active element is used. ON voltage value VGH for turning on, OFF voltage value VGL for turning off the active element, and correction voltage value VE for correcting the potential of the pixel electrode.
It is a program for causing a computer to execute all or some of the steps of applying a scanning signal using a voltage value of a kind to the scanning electrode.

A sixth aspect of the present invention (corresponding to claim 6) is a medium carrying the program of the fifth aspect of the present invention, which can be processed by a computer.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) First, mainly in FIG.
The configuration of the liquid crystal display device of the present embodiment will be described with reference to FIG.

FIG. 2 shows an equivalent circuit of an active matrix type liquid crystal array in the capacitive coupling drive system of the latter stage connection type in the present embodiment, and each reference numeral represents the same means as in FIG.

However, in the present embodiment, the potential of the pixel electrode connected to each active element is corrected by the voltage change of the scanning electrode in the subsequent stage in the scanning direction of the scanning electrode. That is, the display device according to the present embodiment corrects the pixel electrode potential in the scanning direction of the scanning electrodes by the voltage change of the scanning electrodes in the subsequent stage, that is, a so-called downstream connection type active matrix array of the capacitive coupling drive system. It is characterized by a structure.

Next, the operation of the liquid crystal display device of the present embodiment will be described mainly with reference to FIG. Since the characteristic of the operation of the liquid crystal display device of the present embodiment is the capacitive coupling driving method, the latter-stage connection type capacitive coupling driving method in the liquid crystal array configured as described above will be described using the driving waveforms in FIG. To do. Note that FIG. 1 shows the voltage waveforms of the scan electrodes 2n and 2n + 1, the voltage waveform of the signal electrode using polarity inversion with respect to the scan electrode 2n, and the voltage waveform of the pixel electrode 61.

First, in the even-numbered frame period shown in FIG. 1, the voltage of the scan electrode 2n is changed from VGL one horizontal period before the signal voltage of the image signal to the active element 10 connected to the scan electrode 2n is applied from the signal electrode. Change to VGH. While the active element 10 is on, the voltage of the scan electrode 2n + 1 is once changed from VGL to VE.

Next, the voltage of the scan electrode 2n is changed from VGH to V
After changing to GL and applying the signal voltage of the image signal to the active element 10, the voltage of the scan electrode 2n + 1 is set to V.
The active element 11 is turned on by changing from E to VGH.

After that, the voltage of the scan electrode 2n + 1 is set to VGH.
To VGL, and the active element 11 is turned off.

Here, the voltage of the scan electrode 2n + 1 is set to VGL.
Is temporarily changed from VE to VE at the same time as the active element 10 is turned off or thereafter.
Changes the voltage of VGL to VGL via VGH (from VE to V
It is to change to GL).

The voltage of the scan electrode 2n changes from VGL to V
In one horizontal period after the signal voltage of the image signal for the active element 10 is applied from the signal electrode after changing to GH, the voltage value of the scanning signal of the present invention shifts from the off voltage value VGL to the on voltage value VGH. To correspond to the period.
Further, the voltage value of the scan signal of the present invention shifts from the off voltage value VGL to the on voltage value VGH in one horizontal period from the time when the voltage of the scan electrode 2n + 1 changes from VGL to VE to the time when it changes from VE to VGH. Corresponding to the period to do.

In the odd frame period, the scan electrode 2
The voltage waveform of n + 1 is similar to the waveform of scan electrode 2n in the previous frame, and the voltage waveform of scan electrode 2n is similar to the voltage waveform of scan electrode 2n + 1 in the previous frame. However, the timing of changing the voltage of the scan electrode 2n + 1 from VGL to VGH is one horizontal period before the voltage of the scan electrode 2n is changed from VGH to VGL.

Here, the voltage waveform of the scan electrode 2n + 1 is changed from VGL to VGH one horizontal period before the signal voltage of the image signal to the active element 11 is applied from the signal electrode, because the active element 10 is turned off at the same time. Alternatively, after that, the voltage waveform of the scan electrode 2n + 1 is changed to VG.
This is for changing from H to VGL.

Note that the voltage value of the scanning signal of the present invention changes from the off voltage value VGL to the on voltage value for one horizontal period from the time when the voltage of the scan electrode 2n once changes from VGL to VE to the time when it changes from VE to VGH. It corresponds to the period for shifting to VGH. In addition, the voltage of the scan electrode 2n + 1 changes from VGL to VGL.
In one horizontal period after the signal voltage of the image signal to the active element 11 is applied from the signal electrode after changing to GH, the voltage value of the scanning signal of the present invention shifts from the off voltage value VGL to the on voltage value VGH. To correspond to the period.

With the drive waveforms described above, the pixel electrode 60 connected to the active element 10 in an even frame.
At the end of the voltage application of the image signal to the VGH, the punch-through occurs due to the change from VGH to VGL. In addition, the scanning electrode 2n +
The voltage of 1 changes from VE to VGH and from VGH to VGL, that is, when the voltage of 1 relatively changes from VE to VGL, the potential of the potential of the pixel electrode 60 is corrected.

Also in the odd-numbered frame, at the end of the voltage application of the image signal to the pixel electrode 60, punch-through occurs due to the change from the voltage VGH of the scan electrode 2n to VGL, and then from the voltage VGH of the scan electrode 2n + 1 to VGL. The potential correction of the potential of the pixel electrode 60 is performed by the change of.

By designing the voltage so that the condition of VGL-VE = VGH-VGL is satisfied, the potential correction amount for the pixel electrode in the even frame and the potential correction amount for the pixel electrode in the odd frame can be equalized. It is possible (of course, even if such a condition is not satisfied, it is much more preferable than the case where there is a frame to which no correction potential is applied as in the above-mentioned conventional example 1).

Therefore, the voltage VCOM of the common electrode is
By setting the voltage value obtained by subtracting the amount of the punch-through potential from the center value of the amplitude of the image signal voltage to the signal electrode, it is applied to the liquid crystal pixel regardless of whether the image sending signal voltage has a positive polarity or a negative polarity. The total amount of electric charge can be made equal.

Further, according to the present embodiment, as in the case of using the four types of scan electrode voltages, the latter stage connection type capacitive coupling drive system using the three types of scan electrode voltages is used. Since the punch-through potential amount and the correction potential amount can be made equal in each frame with respect to the image signal potential and the common electrode voltage VCOM does not need to be adjusted, the scale of the power supply circuit is reduced, the pixel voltage design is facilitated, and the power supply circuit is reduced. The effect that the power consumption can be reduced can be obtained.

According to the invention, all or part of the above-mentioned liquid crystal display device of the present invention (or device, element,
A program that causes a computer to execute the functions of circuits, units, and the like, and includes a program that operates in cooperation with the computer. Of course, the computer is not limited to pure hardware such as a CPU, but may include firmware, an OS, and peripheral devices.

The present invention also provides a program for causing a computer to execute all or part of the steps (or steps, operations, actions, etc.) of the capacitive coupling driving method of the present invention described above, A program that operates in cooperation with a computer is included.

It should be noted that a part of the invention (or device,
Element, circuit, part, etc.), some steps (or steps, acts, acts, etc.) of the present invention means some means or steps among those plural means or steps, or It means some functions or some operations of means or steps.

In addition, a part of the device (or element,
(Circuits, parts, etc.) means some of the plurality of devices, or means (or elements, circuits, parts, etc.) of some of the devices, or one of the devices. It means a part of the functions of the means.

A computer-readable recording medium in which the program of the present invention is recorded is also included in the present invention. Further, one usage form of the program of the present invention may be a mode in which the program is recorded in a computer-readable recording medium and operates in cooperation with the computer. Further, one usage form of the program of the present invention may be a mode in which the program is transmitted through a transmission medium, read by a computer, and operates in cooperation with the computer. The recording medium includes a ROM and the like, and the transmission medium includes a transmission medium such as the Internet and light, radio waves, sound waves and the like.

The configuration of the present invention may be realized by software or hardware.

Further, the invention is a medium carrying a program for causing a computer to execute all or some of the functions of all or some of the above-mentioned liquid crystal display device of the present invention, which is readable by the computer. Also included is a medium in which the read program cooperates with the computer to perform the functions.

Further, the present invention is a medium carrying a program for causing a computer to execute all or some of the steps of all or some of the steps of the capacitive coupling driving method of the present invention described above. A medium is included that is readable and the program that is read cooperates with the computer to perform the operations.

[0053]

As is apparent from the above description,
INDUSTRIAL APPLICABILITY The present invention has an advantage that the design of a liquid crystal display device can be facilitated.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of drive waveforms of an active matrix type liquid crystal display device according to Embodiment 1 of the present invention.

FIG. 2 is a configuration diagram of an active matrix type liquid crystal array in a capacitive coupling drive system of a latter stage connection type according to the first embodiment of the present invention.

FIG. 3 is a configuration diagram of an active matrix type liquid crystal array in a capacitive coupling drive system of a front stage connection type in Conventional Example 1.

FIG. 4 is an explanatory diagram of drive waveforms of an active matrix type liquid crystal display device in Conventional Example 1.

FIG. 5 is an explanatory diagram of drive waveforms of an active matrix type liquid crystal display device in Conventional Example 2.

[Explanation of symbols]

5 signal electrodes 10 and 11 active elements 20 and 21 connected to signal electrodes and scan electrodes parasitic capacitances 30 and 31 between pixel electrodes and scan electrodes equivalent capacitances 40 and 41 of liquid crystal pixels for accumulating and correcting pixel potentials Storage capacitor 50, 51 Scan electrode 60, 61 Pixel electrode 70 connected to signal electrode via active element 70 Common electrode connected to liquid crystal pixel facing pixel electrode

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G09G 3/20 G09G 3/20 622D 622M 624 624B 3/36 3/36 F term (reference) 2H092 HA02 HA06 JA24 JA37 JA41 NA25 NA26 NA29 PA06 2H093 NA31 NA33 NA34 NB00 NC01 ND10 ND39 ND54 NE03 NG16 5C006 AA01 AA16 AC11 AC22 AC28 AF42 AF44 AF46 AF51 AF71 BB16 BC03 BC06 BF42 FA16 FA18 FA23 FA26 FA45 FA47 FA51 GA22 BB26DD03A02 5C080 A02 GG02 GG08 JJ03 JJ04 KK43

Claims (6)

[Claims] 1. A plurality of active elements respectively connected to a plurality of signal electrodes and a plurality of scanning electrodes arranged in a matrix, a plurality of pixels respectively connected to the active elements via pixel electrodes, A capacitive coupling driving method of a liquid crystal display device of a latter-stage connection type, comprising: a common electrode facing a plurality of pixel electrodes with a plurality of pixels interposed therebetween, wherein voltage application to the signal electrode utilizes polarity inversion. When performed, three types of voltages, an on-voltage value VGH for turning on the active element, an off-voltage value VGL for turning off the active element, and a correction voltage value VE for correcting the potential of the pixel electrode. Applying a scan signal using a value to the scan electrode, wherein the voltage value of the scan signal shifts from the off voltage value VGL to the on voltage value VGH. In the period for which,
(1) A frame to which the compensation voltage value VE is applied,
(2) A capacitive coupling driving method for alternately generating a frame to which the on-voltage value VGH is applied. 2. Between the on-voltage value VGH, the off-voltage value VGL, and the compensation voltage value VE, VGH-
The capacitive coupling driving method according to claim 1, wherein a relationship of VGL = VGL-VE is established. 3. The voltage value of the scan signal is changed from the ON voltage value VGH to the OFF voltage value VG in each frame.
3. The capacitive coupling drive method according to claim 1, wherein the method directly shifts to L. 4. A plurality of active elements respectively connected to a plurality of signal electrodes and a plurality of scanning electrodes arranged in a matrix, a plurality of pixels respectively connected to the active elements via pixel electrodes, A latter-stage connection type liquid crystal display device comprising a common electrode facing a plurality of pixel electrodes with a plurality of pixels sandwiched therebetween, wherein a voltage is applied to the signal electrode by using polarity inversion, Using a coupling driving method, an on-voltage value VGH for turning on the active element, an off-voltage value VGL for turning off the active element, and a correction voltage value VE for correcting the potential of the pixel electrode are used. A scan signal using three kinds of voltage values is applied to the scan electrodes, and the voltage value of the scan signal shifts from the off voltage value VGL to the on voltage value VGH. In the period for,
(1) A frame to which the compensation voltage value VE is applied,
(2) A liquid crystal display device in which the frames to which the on-voltage value VGH is applied alternate. 5. The capacitive coupling driving method according to claim 1, wherein when voltage application to the signal electrode is performed by utilizing polarity inversion, an ON voltage value VGH for turning on the active element, the active element All or part of the step of applying a scan signal to the scan electrode, which uses three kinds of voltage values of an off voltage value VGL for turning off the pixel electrode and a correction voltage value VE for correcting the potential of the pixel electrode. A program that causes a computer to execute. 6. A medium carrying the program according to claim 5, which can be processed by a computer.