JP3501157B2 - Method and circuit for driving liquid crystal device and liquid crystal device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving method, a driving circuit and a display device for a liquid crystal element such as a liquid crystal display panel.

[0002]

2. Description of the Related Art Conventionally, multiplex driving by a voltage averaging method is known as one of the driving methods for the above liquid crystal element.

(Conventional Example 1) FIG. 21 is an applied voltage waveform diagram showing an example of a conventional driving method in the case where a simple matrix type liquid crystal element or the like as shown in FIG. 22 is multiplexed driven by a voltage averaging method. , in Figure 21 (a) · (b) is the voltage waveform applied to the scan electrodes X ₁ · X ₂ respectively, FIG. (c) the voltage applied to the signal electrodes Y ₁汲形, the (d) of FIG
Shows a voltage waveform applied to a pixel where the scan electrode X ₁ and the signal electrode Y ₁ intersect.

In this example, the scan electrodes X ₁ , X _2, ..., X _n are sequentially selected line by line to apply a scan voltage, and depending on whether each pixel on the selected scan electrode is on or off.
Those driven by applying a signal voltage corresponding thereto the signal electrodes Y _l, the Y ₂ ‥‥ Y _m.

However, the one in which the scanning electrodes are selected and driven one line at a time as described above has a problem that good display cannot be obtained unless the driving voltage is relatively high.

(Conventional Example 2) Therefore, in order to lower the driving voltage, a method of sequentially selecting and driving a plurality of scanning electrodes has been proposed (for example, A GENER).
ALIZD ADDRESS TECHNIQU
E FOR RMS RESPONDING MATR
IX LCDS, 1988 INTERNATIONA
L DISPLAY RESEARCH CONFER
ENCE P80-85).

FIG. 23 shows a plurality of scanning electrodes sequentially arranged as described above.
Shows an example of a conventional drive method that selects and drives poles at the same time
FIG. 3A is a waveform diagram of an applied voltage, in which FIG._l・
X₂The voltage waveform applied to the scanning electrode X is shown in FIG.₃・ X
_FourWaveform of voltage applied to the signal electrode Y_lApplied to
Voltage waveform, the scanning electrode X is shown in FIG._lAnd signal electrode Y _l
7 shows a voltage waveform applied to a pixel where and intersect.

In this example, two scanning electrodes are sequentially selected simultaneously to drive and display the display pattern shown in FIG. 22. First, two scanning electrodes X ₁ .X ₂ are selected, Each of the scan electrodes X _l and X _z is, for example, as shown in
A scanning voltage as shown in (a) of 2 is applied, and at the same time, a predetermined signal voltage described later is applied to each of the signal electrodes Y _{1 to} Y _m . Then, the scanning electrodes X ₃ and X ₄ are selected, and the scanning voltage similar to the above is applied to those electrodes, and at the same time, the signal electrodes Y _{1 to} Y _{m are selected.}
Apply signal voltage to. Then, one frame is set until all the scan electrodes X _{1 to} X _n are selected, and this is sequentially repeated.

The voltage waveform applied to the above scanning voltage is, for example, 2 when the number of simultaneously selected scanning electrodes is h.
A waveform having a pulse pattern number of ^h is used, and in this example, a waveform having a pulse pattern number of 2 ^Z = 4 is used.

On the other hand, the signal voltage applied to each of the signal electrodes Y _{1 to} Y _m has the same number of pulse patterns as the scanning voltage, and the signal voltage level of each pulse is the ON / OFF state of the pixel on the simultaneously selected scanning electrodes. OFF and the positive / negative of the scanning voltage pulse applied to the scanning electrode are set for each pulse.

In this example, when the scanning electrodes X ₁ and X ₂ are simultaneously selected as shown in FIG. 23 and a scanning voltage as shown in FIGS. 24A and 24A is applied, The signal voltage waveform of Ya in FIG. 24B is applied to each of the signal electrodes Y _{1 to} Y _m when the pixels on the scan electrodes X ₁ and X ₂ corresponding to the signal electrodes are sequentially turned on and off. The signal voltage waveforms of Yb are applied when they are off / on, Yc when they are both on, and Yd when they are both off.

In the above signal voltage waveform, when the scanning voltage pulse applied to the simultaneously selected scanning electrodes is positive, it is set to 1, and when the scanning voltage pulse is negative, it is set to -1. 1 is set to 1 when the switch is off, and each pulse is compared. Depending on the difference between the number of coincidences and the number of disagreements, when the difference is 2, V ₂ volt, when 0, 0 volt, and -2 Is -V ₂
The voltage of the volt is applied.

[0013] For example a signal voltage waveform of the Ya, since the pixels on the scanning electrodes X _l - X ₂ is sequentially turned on and off, in order, are arranged the -1-1, scanning electrodes X ₁ - X contrast ₂
24, the pulse waveforms in the first half of the period t _l are both negative and are arranged in order of −1 · −1. When the two are compared in order, first, −1 and −1 match, and next, −1 and 1. Therefore, the number of matches is 1, the number of mismatches is 1, the difference between the number of matches and the number of mismatches is 0, and a voltage of 0 V is applied in the first half of the period t ₁ of Ya. Then the second half of the pulse waveform of the period t _l scan electrodes X ₁ is positive, the scanning electrodes X ₂ is sequentially 1--1 because it is also negative and the first half of the period t _1, -1, the pixel When compared in order with 1, the number of matches is 0 and the number of mismatches is 2.
Difference in number of matches and number of mismatches in the second half of the period t _l -2 next Ya the voltage -V ₂ volts is applied.

Furthermore pulse waveform of the first half of the period t ₂ in FIG. 24, since the scanning electrodes X _l is positive scan electrode X ₂ at the negative, in order, -1-1, compared to -1-1 and the order of the pixel Then, the number of matches is 2, the number of mismatches is 0, the difference between the number of matches and the number of mismatches is 2, and the voltage of V ₂ volt is applied in the first half of the period t ₂ of Ya. The pulse waveform in the latter half of the period t ₂ is 1.1 in order because the scanning electrodes X ₁ and X ₂ are both positive. At 1, the difference between the number of matches and the number of mismatches becomes 0, and a voltage of 0 volt is applied in the latter half of the period t ₂ of Ya.

The voltages are set for the other signal voltage waveforms of Yb to Yd in the same manner as described above.

By the way, in the driving method of FIG. 23 driven in accordance with the display pattern of FIG.
Signal electric corresponding to the Ya to the signal electrodes Y _l as shown since the display pattern on the scanning electrodes X ₁ - X ₂ corresponding to the signal electrodes Y _l is sequentially turned on and off (c) of FIG. 23 Voltage is being applied.

In the above example, the positive selection pulse of the scanning voltage waveform is 1, the negative selection pulse is -1, the display of each pixel is -1 when the display is on, and 1 when the display of each pixel is off. Although the signal voltage waveform is set by the difference in the number of disagreements, either one may be set to 1 or -1, and the signal voltage waveform is set only by the number of the coincidences or the number of disagreements without calculating the difference between the number of the coincidences and the number of disagreements. You can also

(Conventional Example 3) FIG. 25 shows another conventional example in which a plurality of scanning electrodes are simultaneously selected and driven. In this example, the scanning electrodes are sequentially selected in units of three lines at a time and shown in FIG. Such a display is made.

That is, first, the three scan electrodes X ₁ .X ₂ .X
₃ Select, FIG. 25 to the scan electrodes X ₁ · X ₂ · X ₃ it like
(A) is applied, and at the same time, a predetermined signal voltage described later is applied to each of the signal electrodes Y _{1 to} Y _m . Then, in FIG. 26, the scanning electrodes X ₄ , X _5, and X ₆ are selected, and the scanning voltage as shown in FIG. _Apply signal voltage to _m . And until all of the scanning electrodes X ₁ to X _n is selected as one frame in FIG. 26, in which sequentially repeated.

Each of the above scanning voltage waveforms has a pulse pattern number of 2 ^h , where h is the number of scanning electrodes selected at the same time as in the prior art example 2. In this example, A waveform with a pulse pattern number of 2 ³ = 8 is used.

The signal voltage applied to each of the signal electrodes Y _{1 to} Y _m has the same number of pulse patterns as the scanning voltage as in the above example, and the voltage level of each pulse is ON / OFF on the selected scanning electrode. A voltage having a magnitude corresponding to OFF is applied. For example, in this example, when the scanning voltage waveform applied to the simultaneously selected scanning electrodes X ₁ , X _2, and X ₃ is a positive pulse, When the on / off pulse is turned off, the on / off of the display data is compared for each pulse, and the signal voltage waveform is set according to the number of mismatches.

[0022] That is, as the number of mismatches applies a pulse voltage V ₃ when the -V _3, V ₂ when the -V _2, 2 is set to 1, 3 when the 0 in FIG. 25 It was done. The above voltage ratio between V ₂ and V ₃ is V ₂ : V ₃ = 1:
3 is set.

Specifically, the scan electrode X _l in FIG.
In the waveform of the voltage applied to X ₂ and X ₃ , the application of the voltage of V ₁ is turned on, the application of the voltage of −V ₁ is turned off, and the pixel display in FIG. When the mark is turned off, the signal electrode Y ₁ and the scan electrode X ₁ in FIG.
・ Display of pixels that intersect with X ₂ and X ₃ is turned on in order.
In contrast, the initial pulse patterns of the voltages applied to the scan electrodes X ₁ , X _2, and X ₃ are OFF, OFF, and OFF, respectively. Since the two are sequentially compared and the number of mismatches is 2, the voltage V ₂ is applied to the first pulse pattern of the signal electrode Y _l as shown in FIG. 25 (c).

The second pulse patterns of the voltage applied to the scan electrodes X ₁ , X _2, and X ₃ are OFF, OFF, and ON, respectively, and when compared with the above-mentioned pixel display ON, ON, and OFF, respectively. , And the number of mismatches is 3, the voltage V ₃ is applied to the second pulse of the signal electrode Y _l . In a similar manner, -V ₂ is applied to the V _2, 4 th pulse to the third pulse, or less, -V
_3, V _2, -V _2, is applied in the order of -V _2.

Further, when the next three scan electrodes X _{4 to} X ₆ are selected and the voltage shown in FIG. 25B is applied to the respective scan electrodes X _{4 to} X ₆ , the respective scan electrodes X _{4 to} X ₆ are applied. A voltage level corresponding to the on / off display of the pixel where the electrodes X _{4 to} X ₆ intersect the signal electrode and the on / off of each pulse pattern of the voltage applied to each of the scan electrodes X _{4 to} X ₆ Is applied as shown in FIG. 25 (c). 25D, the voltage waveform applied to the pixel where the scan electrode X ₁ and the signal electrode Y _l intersect, that is, the voltage waveform applied to the scan electrode X ₁ and the signal electrode Y _1. It is a composite waveform with a voltage waveform.

As described above, the method of sequentially selecting and driving a plurality of scanning electrodes simultaneously realizes the same on / off ratio as the method of selecting and driving one line at a time as shown in FIG. Therefore, there is an advantage that the drive voltage can be suppressed to a low level.

Next, the general requirements, points and procedures of the method of sequentially selecting and driving a plurality of scanning electrodes simultaneously as described above will be described step by step. A. Requirement a) N scan electrodes are divided into N / h subgroups. b) Each subgroup has h address lines. c) At a certain time, the signal electrode has an h-bit word (h
-Bit word).

D _{k * h + 1} , d _{k * h + 2} ... d _{k * h + h} ; d _{k * h + j} = 0 or 1 where 0 ≦ k ≦ (N / h) -1 ( k: subgroup) That is, the display data of one column is d _l , d ₂ , ... dh _h 0th subgroup dh _{+ 1} , dh _{+ 2}・ ・ ・ dh _{+ h} ... .... First subgroup d _{N-h + 1} , d _{N-h + 2} ... d _{N-h + h} ... N / th
It becomes the h-1 subgroup. d) The scan electrode selection pattern is an h-bit word pattern with a period of 2 ^h shown in the following equation.

A _{k * h + 1} , a _{k * h + 2} ... a _{k * h + h} ; a _{k * h + j} = 0 or 1 B. Procedure (1) One subgroup is selected at the same time. (2) One h-bit word is selected as the scan electrode selection pattern. (3) The scan voltage is −Vr for logic 0, + Vr for logic 1, and 0 V when not selected. (4) The scan electrodes and signal electrodes of the selected subgroup are compared bit by bit. (5) Determine the number i of pattern mismatches between the scan electrodes and the signal electrodes.

[0030]

[Equation 1]

(6) The voltage applied to the signal electrode is V _(i) . i is the number of disagreements. (Select one of the predetermined voltages according to the number of mismatches) (7) Determine the signal voltage (simultaneously or in parallel) based on the above method. (8) The scanning voltage and the signal voltage obtained as described above are applied to the display only during the time interval Δt. However, Δt is the minimum pulse width. (9) A new scan electrode selection pattern is selected, the above (4) to (6) are calculated again, and the next signal voltage is determined.
This is also applied by Δt. (10) One cycle (cycle) ends when all 2 ^h scan electrode selection patterns appear in each subgroup and N / h subgroups are selected.

1 cycle = Δt · 2 ^h · (N / h) C.I. Analysis Consider a scan electrode selection pattern when there are i mismatches.

When the scan electrode selection pattern of h-bit word length does not match the data pattern of the same h-bit word length by i bits, the number is _h C _i = {h! } / {I! (Hi)! } = Ci exist.

For example, h = 3, scan electrode selection pattern =
Considering the case of (0,0,0), the following table is obtained.

[0035]

[Table 1]

These are determined not by the scanning electrode selection pattern but by the number of bits of the word.

The amplitude V of the instantaneous voltage applied to the pixel
_{In the pixel} , when the scanning voltage is V _row and the signal voltage is V _column , V _pixel = (V _column −V _row ) or (V _row −V _column ) where V _row = ± Vr V _column = V _(i) Then, V _pixel = ten Vr 1 V _(i) or −Vr 1 V _(i) .

If V _row = ± Vr V _column = ± V _(i) , then V _pixel = Vr-V _(i) , Vr tens V _(i) , -Vr-V _(i) or -Vr tens V _{( i)} That is, _Vpixel = | Vr−V _(i) | or | Vr10V _(i) |.

[0039] Thus, specific amplitudes applied to pixels in the selected row - a (Vr tens V _(i)) or _{(Vr- V (i)) V} (i) in the non-selected rows. (If V _(i) is considered to be ambipolar, it becomes the description as in the above-mentioned document.) Generally, the voltage applied to the pixel should be as large as possible in the ON pixel and as small as possible in the OFF pixel. It is desirable to realize a high selection ratio.

Therefore, when on, | Vr + V _(i) | favors on-pixels and | Vr-V _(i) | favors on-pixels.

[0041] When _{off, | Vr-V (i)} | acts in favor of off-pixel, | Vr tens of V _(i) | may work against the off-pixel.

Here, the advantage for ON is to increase the effective voltage, and the disadvantage for ON is to decrease the effective voltage.

The number of combinations that i pieces selected from among the h _{bits, Ci = h C i = {} h! } / {I! (Hi)! }, And if there is a mismatch with i, this is i out of h bits.
This is the number when the bits do not match, and the number of mismatches is i at each level, so the total number of mismatches (total mismatch) is i · Ci.

Since these are distributed over h bits, the average number of mismatches per pixel (per bit) Bi is Bi = iCi / h (pieces / pixel).

The signal voltage V increases as the number of mismatches increases.
_When the level of _(i) is increased, V _pixel = V _row −V _column decreases as the number of mismatches increases.

Considering the mismatch to be a disadvantage for the on-pixel of interest, the number of mismatches gives the number of disadvantageous voltages (signal voltages).

Therefore, the number of disadvantageous voltages per pixel (on average) is Bi = i.Ci / h.

By the way, since i / h of Ci is disadvantageous, the rest, that is, Ai = {(h-i) / h} .Ci works advantageously. In addition, {(h-i) / h} · Ci ten (i / h) · Ci = (h /
h) Ci = Ci, Ai = Ci-Bi = {(h-1)! } / {I · (h−i−1)! } However, it is h> = i + 1.

In summary, V _ON (r, m, s) = {(S ₁ tens S ₂ tens S ₃ ) / S ₄ } ^1/2 V _OFF (r, m, s) = {(S ₅ 10 S ₆ 10 S ₃ ) / S ₄ ) ^1/2 . In addition, Is.

Further, Vr / V ₀ = N ^1/2 / h ··· Row selection voltage V _(i) / V ₀ = (h-2i) / h = {1- (2i / h)}
... a column voltage, an _{R = (V ON / V OFF} ) max = {(N l / 2 dozen ^{1) / (N 1/2 -1)} } l / 2.

[0051]

However, in the conventional driving methods such as the above-mentioned conventional examples 1 to 3, as shown in FIG. 27, for example, in the first frame F, after a selection voltage is applied to a certain pixel, , Until the selection voltage is applied to the pixel in the next frame, the brightness T gradually decreases and the transmittance T in the ON state decreases with the passage of time t, while the transmittance T in the OFF state is slightly higher. However, there is a problem that the contrast between the ON state and the OFF state is poor.

Further, in the above-mentioned conventional example 3, as shown in FIG. 25, the pulse width applied to the scan electrodes and the signal electrodes becomes narrower as the number of scan electrodes selected at the same time becomes narrower, so that crosstalk due to the waveform waveform is reduced. There is a problem that the image quality increases and the image quality deteriorates. The problem becomes more serious, for example, when gradation display is performed by modulating the pulse width.

The present invention has been proposed in view of the above conventional problems, and an object thereof is to be able to favorably drive a liquid crystal element having a large number of electrodes and to have good display performance. An object is to provide a driving method, a driving circuit, and a display device for a liquid crystal element or the like.

[0054]

According to a method of driving a liquid crystal device described in the present invention, a plurality of scan electrodes and a plurality of signal electrodes intersecting the plurality of scan electrodes, each of the scan electrodes and each of the signal electrodes are provided. In a method of driving a liquid crystal device including a liquid crystal sandwiched between a plurality of scan electrodes, the plurality of scan electrodes are divided into subgroups, the scan electrodes in the subgroup are simultaneously selected, and the scan electrodes are simultaneously selected. Is a scanning voltage applied in a plurality of selection periods within one frame,
The plurality of selection periods for applying the scanning voltage are continuously set in one frame without an interval, and the scanning voltage applied in the plurality of selection periods continuously set in one frame Waveform has a pulse width larger than the selection period and has different frequency components in the plurality of simultaneously selected scan electrodes, and the frequency component is mutually different in the plurality of simultaneously selected scan electrodes. It is characterized in that the signal voltage is set so as not to differ greatly, and a signal voltage set based on the data to be displayed and the waveform of the scanning voltage is applied to the signal electrode.

In addition, the liquid crystal device according to the present invention is sandwiched between a plurality of scanning electrodes and a plurality of signal electrodes intersecting the plurality of scanning electrodes, and between the scanning electrodes and the signal electrodes. In a liquid crystal device including a liquid crystal, the plurality of scan electrodes are divided into subgroups, the scan electrodes in the subgroups are simultaneously selected, and the scan electrodes that are simultaneously selected are selected in a plurality of selection periods within one frame. A plurality of selection periods in which a scanning voltage is applied are continuously set in one frame without an interval, and the plurality of selection periods are continuously set in one frame. The waveform of the scanning voltage applied during the period has a pulse width larger than that in the selection period, the plurality of simultaneously selected scanning electrodes have different frequency components, and the frequency component is A plurality of scanning electrodes selected at the same time are set so as not to be significantly different from each other, and a signal voltage set based on the data to be displayed and the waveform of the scanning voltage is applied to the signal electrodes. And

Further, in the drive circuit of the liquid crystal device according to the present invention, a plurality of scanning electrodes and a plurality of signal electrodes intersecting the plurality of scanning electrodes, and between the scanning electrodes and the signal electrodes are provided. In a drive circuit of a liquid crystal device including a sandwiched liquid crystal, the plurality of scan electrodes are divided into subgroups, the scan electrodes in the subgroups are simultaneously selected, and the scan electrodes that are simultaneously selected are within one frame. Scanning voltage is applied in a plurality of selection periods, and the plurality of selection periods in which the scanning voltage is applied are continuously set in one frame with no interval and continuously set in one frame. The waveform of the scan voltage applied during the plurality of selection periods has a pulse width larger than that of the selection period, and has different frequency components between the plurality of simultaneously selected scan electrodes, and The frequency component is set so that the plurality of simultaneously selected scanning electrodes do not greatly differ from each other, and a signal voltage set based on the data to be displayed and the waveform of the scanning voltage is applied to the signal electrode. It is characterized by

Therefore, the method of driving a liquid crystal element or the like according to the present invention is a method of driving a liquid crystal element in which a liquid crystal element formed by interposing a liquid crystal layer between a substrate having scan electrodes and a substrate having signal electrodes is multiplexed. In the method, a plurality of scan electrodes are sequentially selected at the same time, and the selection period is divided into a plurality of times for driving in one frame. By adopting the driving method as described above, for example, in a first frame, a voltage is applied to a pixel several times from when the selection voltage is applied to the pixel in the next frame. Is applied, the brightness is maintained, and it is possible to prevent a decrease in contrast.

The drive circuit for a liquid crystal element or the like according to the present invention includes selection pulse data generated from the scan data generation circuit and display data on a plurality of simultaneously selected scan electrodes sequentially read from the frame memory. Is calculated by the calculation circuit, the conversion data as the calculation result is transferred to the signal electrode driver, the scan data generated from the scan data generating circuit is transferred to the scan electrode driver, and after scanning one screen, the next The above operation is repeated with the selected pulse data and the display data, and is repeated a plurality of times in one frame. By using the drive circuit as described above, it becomes possible to easily and surely execute the drive method as described above.

Further, in the display device according to the present invention, the select pulse data generated from the scan data generating circuit and the display data on the plurality of simultaneously selected scan electrodes sequentially read from the frame memory are processed by the arithmetic circuit. After the calculation, the converted data as the calculation result is transferred to the signal electrode driver, the scan data generated from the scan data generating circuit is transferred to the scan electrode driver, and when one screen is completely scanned, the next selected pulse data And a drive circuit configured to repeat the above operation according to display data, sequentially select a plurality of scan electrodes at the same time, and drive the selection period in a plurality of times in one frame. Is characterized by. With the above configuration, it is possible to provide a display device with good contrast.

[0060]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a driving method for a liquid crystal element and the like, a driving circuit and a display device according to the present invention will be specifically described based on the embodiments shown in the drawings.

(Embodiment 1) FIG. 1 is an applied voltage waveform diagram showing an embodiment of a method for driving a liquid crystal display device according to the present invention. FIG. 1 (a) is a diagram showing applied voltage to scan electrodes X ₁ and X _2. Voltage waveform, (b) is a voltage waveform applied to the scan electrodes X ₃ and X ₄ ,
(C) shows a voltage waveform applied to the signal electrode Y ₁ , and (d) shows a voltage waveform applied to a pixel where the scan electrode X ₁ and the signal electrode Y ₁ intersect.

FIG. 2 is a plan view showing a schematic structure of a liquid crystal element or the like (liquid crystal display module) driven by the above-mentioned applied voltage. In the figure, 1 is a scan electrode driver, 2 is a signal electrode driver, and X ₁ and X ₁ . ₂ ... X _n are scanning electrodes, and Y ₁ , Y ₂ ... Y _m are signal electrodes.

This embodiment is similar to FIG.
In the driving method shown in FIG. 3, the display is performed as shown in FIG. 2 by driving the selection period twice in one frame F.

That is, first, as shown in FIG._l
・ X₂Select the scan electrode X_l・ X₂In Fig. 23
Period t_lImmediately after applying the scanning voltage of
Electrode Y _l~ Y_mSignals set with the same requirements as the above-mentioned conventional example
Voltage is applied, then scan electrode X₃・ X_FourSelect above
Scan electrode X_l・ X₂Simultaneously when applying the same scanning voltage as
Each signal electrode Y₁~ Y_mApply a signal voltage to the
This is all scan electrodes X_l~ X_nRepeat until is selected
You Then again scan electrode X_l・ X₂Select
Period t₂Immediately after applying the scanning voltage of
Electrode Y₁~ Y_mSignal voltage to the scan electrode X₃
・ X_FourTo apply the scanning voltage and simultaneously
Electrode Y₁~ Y_mApply a signal voltage to the
Pole X_l~ X_nRepeat until is selected. The above operation 1
By executing it in frame F, you can display one screen
It is performed and this is sequentially repeated.

By driving as described above, an optical response as shown in FIG. 3 is obtained, and as is clear from the comparison with the conventional example of FIG. 27, it is brighter than before in the on state and darker than before in the off state. Therefore, the contrast can be improved and the flicker can be reduced.

Next, a configuration example of a drive circuit for executing the above-described drive method will be described with reference to FIGS.

FIG. 4 is a block diagram showing an example of a drive circuit. In the figure, 1 is a scan electrode driver, 2 is a signal electrode driver, 3 is a frame memory, 4 is an arithmetic circuit, 5 is a scan data generation circuit, and 6 is a circuit. It is a latch.

FIG. 5 is a block diagram of the scan electrode driver. 11 is a shift register, 12 is a latch, 13 is a decoder, and 14 is a level shifter.

FIG. 6 is a block diagram of the signal electrode driver, in which 21 is a shift register, 22 is a latch, 23 is a decoder, and 24 is a level shifter.

In the above configuration, each scanning voltage waveform is
Data generated by the scan data generating circuit 5 of FIG. 4 which indicates positive selection, negative selection, or non-selection is generated and transferred to the scan electrode driver 1.

In the scan electrode driver 1, as shown in FIG. 5, the scan data signal S3 from the scan data generating circuit 5 is transferred to the shift register 11 by the scan shift clock signal S5, and the data of each scan electrode in one scan period is transferred. After the transfer, each data is latched by the latch signal S6, the data representing the state of each scan electrode is decoded, and one of the three switches is turned on by the analog switch 15 for each output to select the positive selection. The voltage V ₁ is output to the selected scan electrode, the voltage −V ₁ is output when the negative selection is performed, and the voltage 0 is output when the negative selection is not performed.

On the other hand, for each signal voltage waveform, the display data signal Sl for each of the two simultaneously selected scanning electrodes from the frame memory 3 is read, and the selected pulse data is selected from the display data signal Sl and the scanning data signal S3. Are latched, and the display data signal Sl and the selection pulse data signal S4 are converted by the arithmetic circuit 4. The data conversion is performed, for example, in the manner described in the second conventional example, and is transferred to the signal electrode driver 2.

In the signal electrode driver 2, as shown in FIG. 6, the data signal S2 from the arithmetic circuit 45 is transferred to the shift register 21 by the shift clock signal S7, and the data of each scanning electrode in one scanning period is transferred and then latched. Signal S
Each data is latched by 8, the data representing the state of each scan electrode is decoded, and one of the three switches is turned on by the analog switch 25 for each output, and V is turned on.
_2, it outputs one of the voltages of -V _2, 0 volts to the respective signal electrodes.

By using the driving circuit as described above, the driving method as described above can be easily and surely executed.

If a display device having the above-mentioned display element or the like is provided with the above-mentioned drive circuit and the above-mentioned drive method is executed, a display device with high contrast can be obtained. .

In the above embodiment, the selection period is set to 1
Although the voltage is applied twice in the frame F, the voltage may be applied twice or more, for example, four times. Further, in the above-described embodiment, two scan electrodes are selected according to the arrangement order, but they may be selected without necessarily following the arrangement order. The above changes are the same in the examples described later.

(Embodiment 2) FIG. 7 is an applied voltage waveform diagram showing another embodiment of the method for driving a liquid crystal display device according to the present invention.

In this embodiment, the scanning voltage waveforms applied to the simultaneously selected scanning electrodes are alternately switched every frame F. The other structure is the same as that of the first embodiment.

As described above, if the scanning voltage waveforms applied to the simultaneously selected scanning electrodes are alternated for each frame F, it is possible to prevent the occurrence of display unevenness due to the difference in the applied voltage waveforms.

Also in this embodiment, since the voltage is applied by dividing the selection period into two times within one frame F, the contrast can be improved and the flicker can be reduced as in the first embodiment.

Further, in this embodiment, the same drive circuit as that of the above embodiment can be used, and a display device having high display quality using the same can be provided.

In the above embodiment, the scanning voltage waveforms are switched every frame, but they may be switched every plural frames.

In the first and second embodiments, the case where two scanning electrodes are simultaneously selected has been described as an example, but it is also possible to select and drive three or more scanning electrodes at the same time as in later-described embodiments. . In that case, as in the second embodiment, the scanning voltage waveforms applied to the scanning electrodes selected at the same time can be sequentially replaced every other frame or every other frames.

(Embodiment 3) FIG. 8 is an applied voltage waveform diagram showing another embodiment of the method for driving a liquid crystal element or the like according to the present invention. FIG. 8 (a) shows application of voltage to scan electrodes X ₁ and X ₂ . Voltage waveform, (b) is a voltage waveform applied to the scan electrodes X ₃ and X ₄ ,
(C) shows a voltage waveform applied to the signal electrode Y _l , and (d) shows a voltage waveform applied to a pixel at which the scanning electrode X _l and the signal electrode Y _l intersect.

This embodiment is similar to the above-mentioned first embodiment, and simultaneously performs two operations.
Scan electrodes are selected one by one, a scan voltage having a voltage waveform as shown in FIG. 8A is applied to the simultaneously selected scan electrodes, and the selection period is driven twice in one frame. By doing so, the display as shown in FIG. 2 is performed.

The order of selecting the scan electrodes is the same as in the first embodiment. First, the scan electrodes X ₁ and X ₂ are selected, and the scan voltage is applied to the scan electrodes X ₁ and X ₂ in the period of t _1. At the same time, a predetermined signal voltage corresponding to the display data is applied to each of the signal electrodes Y _{1 to} Y _m , and then the scan electrodes X ₃ and X ₄ are selected to perform the same scan voltage as the scan electrodes X ₁ and X _2. Is applied in the period of t ₁₁ , and at the same time, a predetermined signal voltage corresponding to the display data is applied to each of the signal electrodes Y _{1 to} Y _m , and this is applied to all scan electrodes X 1.
Repeat until _{1 to Xn} are selected.

Next, the scan electrodes X _l and X ₂ are selected again and t
At the same time as applying the scanning voltage in the period of ₂ , each signal electrode Y ₁
To Y _m are applied with a predetermined signal voltage according to display data, and then the scan electrodes X ₃ and X ₄ are selected to select the scan electrodes X ₁ and X _2.
The same scanning voltage is applied during the period of t ₁₂ and at the same time, a predetermined signal voltage corresponding to the display data is applied to each signal electrode Y _{1 to} Y _m , and all the scanning electrodes X _{1 to} X _n select it. Repeat until done. The above operation is executed within one frame F to display one screen, and this is sequentially repeated.

In this embodiment, the waveform of the scanning voltage applied to each scanning electrode is inverted for each frame to perform so-called AC driving. In this case, it is also possible to invert the positive / negative for every plurality of frames, and the AC drive as described above can be applied to the above-mentioned embodiment or the embodiment described later.

In the present embodiment, the signal voltage set in the same manner as in the conventional example 2 and the example 1 is applied to each of the signal electrodes Y _{1 to} Y _m described above. A description will be given based on FIGS. 9 and 10.

FIG. 9 shows, for example, the scan electrodes X which are simultaneously selected.
4 shows four types of display patterns of pixels on _l · X ₂ . That is, in the figure, the black circle is turned on and the white circle is turned off. In the display pattern a, the pixels on both scan electrodes X ₁ and X ₂ are both off, and in the display pattern b, the dormitory on scan electrode X ₁ is off. And the pixel on the scan electrode X ₂ is turned on, and the display pattern c
_{Shows the} case where the pixel on the scan electrode X _{l is} on and the pixel on the scan electrode X ₂ is off, and the display pattern d is the case where both the pixels on both scan electrodes X _l and X ₂ are on.

FIG. 10 shows the relationship between the scanning voltage waveform applied to the simultaneously selected scanning electrodes and the signal voltage waveform applied to each signal electrode. X ₁ · X ₂ in FIG. The scanning voltage waveforms applied to the scanning electrodes X ₁ and X ₂ , Ya to Yd in FIG. 9B are the display patterns a to A in FIG.
indicating the respective signal electrodes Y _l signal voltage waveform applied to to Y _m in response to d.

That is, the pixels on both scan electrodes X ₁ and X ₂ are shown in FIG.
When both are off as in the display pattern a, the signal voltage waveform of Ya in FIG. 10B is applied,
Similarly, it is indicated that a signal voltage waveform of Yb is applied in the case of display pattern b, a signal voltage waveform of Yc is applied in the case of display pattern c, and a signal voltage waveform of Yd is applied in the case of display pattern d.

The above-mentioned signal voltage waveform is 1, when the scanning voltage pulse applied to each scanning electrode X ₁ · X ₂ is positive, −1 when the scanning voltage pulse applied to each scanning electrode X ₁ · X ₂ is negative, as in the case of the conventional example 2 and the example 1. when display of each pixel is on -1, compared assuming the off 1 and for each pulse, the difference between the number of matches and number of mismatches is, V ₂ volts when 2, when the 0 0 Volt, -2 at-
The V ₂ volts is obtained so as to respectively applied.

For example, when both scan electrodes X ₁ and X ₂ are off as in the display pattern a of FIG. 9, both are 1
And, when arranged in order, becomes 1.1. On the other hand,
In the period of t ₁ at 0, the pulse waveform of the scan electrode X ₁ is positive, and the pulse waveform of the scan electrode X ₂ is negative, and thus becomes −1. Comparing 1 · −1 and 1.1 of the above display in order, the former is matched with 1 and 1, the latter is not matched with −1,
Since the number of matches is 1 and the number of mismatches is also 1, subtracting the number of mismatches from the number of matches gives 0, and 0 volt is applied during the period of t ₁ of Ya. Further, in the period of t ₂ , the pulse waveforms of the scan electrodes X ₁ and X ₂ are both positive, so that they are 1.1, and when compared with 1.1 in the above display in order, both match, the number of matches is 2, and the number of mismatches is 2. Is 0, so the number of disagreements is subtracted from the number of coincidences to be 2, and the signal voltage of V ₂ volts is applied during the period t ₂ of Ya.

A predetermined voltage is applied to the other signal voltage waveforms Yb to Yd according to the difference between the number of matches and the number of mismatches in a similar manner.

Incidentally, according to the display pattern of FIG.
In the driving method of FIG. 8 according to the present embodiment driven,
Signal electrode Y of FIG._lScan electrode X corresponding to_l・ X₂Table above
Since the display pattern is on / off, the display pattern in FIG.
Corresponding to the turn, signal electrode Y _lIs shown in Fig. 8 (c).
Like t_lAnd t₂Signal corresponding to Yc in the period
Voltage is being applied.

The display pattern on the scan electrodes X ₃ and X ₄ corresponding to the signal electrode Y ₁ in FIG. 2 is also on / off, which corresponds to the display pattern in FIG. 9c and is shown in FIG. 8 (c). As described above, the signal voltage corresponding to Yc is applied to the signal electrode Y ₁ during the period of t _ll and t _l2 .

As described above, also in this embodiment, two scanning electrodes are sequentially selected and the selected period is divided into two times for driving in one frame F, so that the same as in the first embodiment. The effect can be obtained.

Actually, when 240 scanning electrodes were provided and the driving voltage was V _I = 16.8 V and V ₂ = 2.1 V, the optical response was the same as in FIG.
In the on-state, it became brighter than in the past, and in the off-state, it became darker than before and the contrast was improved, and flicker could be reduced.

Also in the driving method of the present embodiment, the drive circuit shown in FIG. 4 similar to that of the first embodiment, the scan electrode driver shown in FIG. 5 and the signal electrode driver shown in FIG. 6 can be used. In this case, the calculation of the difference between the number of coincidences and the number of non-coincidences is performed by the arithmetic circuit 4 in FIG. 4 similarly to the above-described embodiment, and the signal converted by the arithmetic circuit 4 is transferred to the signal electrode driver 2. A signal voltage waveform to be applied to each signal electrode may be created.

By using the driving circuit as described above, it is possible to easily and surely execute the driving method as described above and to provide a display device having excellent display performance.

(Embodiment 4) FIG. 11 is an applied voltage waveform diagram showing another embodiment of the method for driving a liquid crystal element or the like according to the present invention. FIG. 11 (a) shows the applied voltage waveforms applied to the scanning electrodes X _{1 to} X _4. Voltage waveform, (b) is a voltage waveform applied to the scan electrodes X ₅ and X ₆ ,
(C) shows a voltage waveform applied to the signal electrode Y _l , and (d) shows a voltage waveform applied to a pixel at which the scan electrode X ₁ and the signal electrode Y _l intersect.

In this embodiment, four scanning electrodes are selected at the same time, a scanning voltage having a voltage waveform as shown in FIG. 11A is applied to the simultaneously selected scanning electrodes, and the selection period is set to 1 The display as shown in FIG. 2 is performed by driving the frame four times.

That is, first, the scan electrodes X _{1 to} X ₄ are selected,
A scan voltage is applied to the scan electrodes X _{1 to} X ₄ in a period of t ₁ , and at the same time, a predetermined signal voltage according to display data is applied to each of the signal electrodes Y _{1 to} Y _m , and then the scan electrodes X _{5 to} X 4. Select ₈ . Note that FIG. 11B shows only the scanning electrodes X ₅ and X ₆ due to space limitations. The selected scan electrodes X _{5 to} X ₈
At the same time by applying a scanning voltage similar to the scanning electrodes X ₁ to X ₄ in the period t _11, a predetermined signal voltage corresponding to display data to the signal electrodes Y _l to Y _m is applied, which all Repeat until the scan electrodes X _{1 to} X _n are selected.

Next, the scan electrodes X _{1 to} X ₄ are selected again and t
At the same time as applying the scanning voltage in the period of ₂ , each signal electrode Y _l
To Y _m , a predetermined signal voltage corresponding to the display data is applied, and then the scan electrodes X _{5 to} X ₈ are selected to select the scan electrodes X ₁ and X _2.
And simultaneously applying the same scan voltage in the period t _l2 and, a predetermined signal voltage corresponding to display data to the signal electrodes Y _l to Y _m is applied, all the scanning electrodes X ₁ to X _n This selection Repeat until done.

Then, the same operation as described above is repeated four times in one frame F to display one screen.

Also in the present embodiment, the waveform of the scanning voltage applied to each scanning electrode is inverted for each frame to perform so-called AC driving.

In this embodiment, the signal voltage set in the same manner as in the third embodiment is applied to each of the signal electrodes Y _{1 to} Y _m , and the procedure is shown in FIG.
And it demonstrates based on FIG.

[0109] Figure 12 shows a display pattern on the scan electrodes, for example, the scan electrodes X ₁ to X on ₄ simultaneously selected, the black circles in FIG ON, turns off the white circles,
Eight display patterns a to h are illustrated.

FIG. 13A shows the scanning voltage waveforms applied to the scanning electrodes X _{1 to} X _4, and Ya to Yh in FIG. 13B.
Are signal electrodes Y _l according to the display patterns a to h of FIG.
3 shows signal voltage waveforms applied to Y _m .

That is, the scan electrodes X _{1 to} X ₄ which are simultaneously selected
When all the upper pixels are off like the display pattern a in FIG. 12, Ya in FIG.
Similarly, when the display pattern b is Yb, the display pattern c is Yc, and the display pattern d is
In the case of Y, the display pattern e is Ye, the display pattern f is Yf, the display pattern g is Yg, and the display pattern h is Yh.

The above-mentioned signal voltage waveform is ₁ when the scanning voltage waveform applied to each scanning electrode X _{1 to} X ₄ is a positive selection pulse, and is − when the scanning voltage waveform is a negative selection pulse, as in the third embodiment.
1, -1 when the display of each pixel is on, 1 when it is off
The number of matches and the number of mismatches are calculated on the assumption that the difference between the number of matches and the number of mismatches is 4 V, ₃ V, 2 V, ₂ V, 0 V, and -2. Is -V ₂ volts,
When -4 so that a voltage of -V ₃ volts respectively. The ratio of the above zero pressure V ₂ · V ₃ is V ₂ :
It is set to V ₃ = 1: 2.

For example, the display pattern a in FIG.
Scan electrode X₁~ X_FourWhen all the pixels above are off,
The display is 1, and when they are arranged in order,
On the other hand, t in FIG.₁In the period of
Is the scan electrode X₁~ X_FourIs 1 because all the waveforms of are positive,
When they are arranged in order, they become 1.1.1.1.1, and both are compared in order.
Then all match, the total number of matches is 4, the number of mismatches is 0
Then, if the number of mismatches is subtracted from the number of matches, it becomes 4._l
During the period₃A voltage of volt is applied. Also t ₂Period of
In between, four scan electrodes X₁~ X_FourWaveforms are positive and positive in order
・ Because it is negative and negative, it is 1.1 ・ -1 ・ -1 in sequence,
The number of matches can be compared by comparing the above display with 1.1.1.1.
Is 2, the number of mismatches is also 2, and 0 is obtained by subtracting the number of mismatches from the number of matches
And then Ya's t₂0 volt is applied during the period
Be done. Similarly t₃In the period of, four scan electrodes X₁~ X_Four
Waveforms are positive / negative / positive / negative in order, so 1-
It is 1 ・ 1 ・ -1, and it is in order from 1 ・ 1 ・ 1 ・ 1 in the above display
The number of matches is 2, the number of mismatches is 2, and
If the number of disagreements is subtracted, it becomes 0, and t of Ya₃0 during the period
A voltage of volt is applied. Furthermore t_FourIn the period of 4
Two scan electrodes X₁~ X_FourWaveforms are positive, negative, negative, positive
Therefore, it is 1--1, -1.1 in order, and the above display
When compared in order with 1.1.1.1.1, the number of matches is 2,
The matching number is also 2, and if the number of mismatches is subtracted from the number of matches, it becomes 0, and Y
a t_FourA voltage of 0 volt is applied during the period.

Next, in the display pattern shown in FIG. 12B, the pixels on the scan electrodes X _{1 to} X ₄ are turned on / off in order.
Because it is on-off Yes -1, 1, -1, 1, in the period t ₁ in FIG. 13 (a) In contrast, because all waveform of the scanning electrodes X ₁ to X ₄ are positive, 1 in order
When the two are compared in order, the number of matches is 2, the number of mismatches is 2, and when the number of mismatches is subtracted from the number of matches, it becomes 0, and the voltage of 0 volt is obtained during the period of t _l of Yb. Is applied.

In the period of t ₂ , four scan electrodes X ₁ to
The waveform of X ₄ is positive / positive / negative / negative in order, so 1 in order
・ 1 ・ -1 ・ -1 and -1 ・ 1 ・ -1 in the above display
・ Comparison with 1 in order shows that there are 2 matches and 2 mismatches,
When the number of mismatches is subtracted from the number of matches, it becomes 0, and a voltage of 0 volt is applied during the period t ₂ of Yb.

Similarly, during the period of t ₃ , the four scan electrodes X ₁
The waveforms of X ₄ to X ₄ are positive, negative, positive, and negative, respectively, so that they are 1-1-1.-1 in order, and -1.1-
In comparison to the 1-1 and forward, the number of matches in all mismatch 0, with the number of mismatches is 4, becomes -4 Subtracting the number of mismatches from the number of matches, the period t ₃ of Yb voltage of -V ₃ volts applied To be done.

Further, in the period of t ₄ , the four scan electrodes X ₁
Since the waveforms of X ₄ to X ₄ are positive, negative, negative and positive in order, they are 1 · −1 · −1 · 1 in order, and −1.1 · − of the above display
Comparing with 1 and 1 in order, the number of matches is 2, and the number of mismatches is also 2.
Then, when the number of mismatches is subtracted from the number of matches, it becomes 0, and t _{4 of} Yb
A voltage of 0 volt is applied during the period.

In the same manner for the other display patterns c to h, when the difference between the number of coincidences and the number of non-coincidences is 4, it is V ₃ volt, when it is ₂ , the voltage is V ₂ volt, when it is 0, 0 volt, -2.
In this case, a voltage of -V ₂ V is applied in the case of, and a voltage of 1 V ₃ is applied in the case of -4, and signal voltage waveforms Yc to Yh corresponding to the respective display patterns c to h are formed.
It should be noted that eight display patterns other than the eight display patterns a to h shown in FIG. 12 can be generated, and the signal voltage waveforms are formed for these display patterns in the same manner as described above.

By comparing the display contents of each pixel on the scan electrodes selected at the same time with the polarity of the selection pulse of the scan electrode waveform, the difference between the number of coincidence and the number of non-coincidence is calculated. A signal voltage according to the display content is applied to each signal electrode. Incidentally, in the driving method of FIG. 11 according to the present embodiment, which is driven according to the display pattern of FIG. 2, the display patterns on the scan electrodes X _{1 to} X ₄ corresponding to the signal electrode Y ₁ of FIG. Since it is on / off / on / off, it corresponds to the display pattern b in FIG. 12, and the signal electrode Y _l is t ₁ · as shown in FIG.
During the period of t ₂ , t _3, and t ₄ , the signal voltage corresponding to Yb in FIG. 13B is applied.

As described above, also in the present embodiment, four scanning electrodes are sequentially selected and the selected period is divided into four times for driving in one frame F. Therefore, the same as in the first embodiment. The effect can be obtained.

Actually, 240 scanning electrodes are provided and the driving voltage is V _l = 12 V, V ₂ = 1.5 V, V ₃ =
When driven at 3 volts, the same optical response as in FIG. 3 was obtained, and when in the on state, it was brighter than in the past, and when in the off state, it was darker than in the past and contrast was improved, and flicker could be reduced.

Also in the driving method of this embodiment, the drive circuit shown in FIG. 4 which is substantially the same as that in the first embodiment, the scan electrode driver shown in FIG. 5 and the signal electrode driver similar to FIG. 6 can be used. it can.

In this case, the calculation of the difference between the number of coincidences and the number of non-coincidences is performed by the arithmetic circuit 4 shown in FIG. 4 as in the above embodiment, and the signal converted by the arithmetic circuit 4 is sent to the signal electrode driver 2. A signal voltage waveform to be transferred and applied to each signal electrode may be created.

At this time, the analog switch 25 of the signal electrode driver shown in FIG. 6 is provided with three switches for each of the signal electrodes Y _{1 to} Y _m to manually apply three kinds of voltages of V2, 0 and -V2. its is a configuration to output either voltage, in the present embodiment provided with five switches for each signal electrodes _{Y 1 ~Y m V3, V2,0,} -V2, 5 single V3
It may be configured so that the seed voltage is input and any one of the voltages is output. By using the driving circuit as described above, it is possible to easily and surely execute the driving method as described above and to provide a display device having excellent display performance.

In the third and fourth embodiments, the selection period is divided into two or four times within one frame F, but the division number is arbitrary.

In the third and fourth embodiments described above, two or four scanning electrodes are selected at the same time, but three or four or more scanning electrodes can be selected and driven.

(Embodiment 5) FIG. 14 is an applied voltage waveform diagram showing an embodiment of a method for driving a liquid crystal element or the like according to the present invention.

In the conventional example shown in FIG. 25, a plurality of scanning electrodes are sequentially selected at the same time, and the selection period thereof is collectively provided at one place in one frame F. The period is divided into a plurality of times in one frame F.

In particular, in the case of the drawing, the voltage waveform consisting of eight pulse patterns (blocks) applied to the scan electrodes and the signal electrodes in the conventional example of FIG. 25 is divided into eight at regular intervals for each pulse pattern. The following shows an example of output.

[0130] That is, the first three scanning electrodes selected for X _l · X ₂ · X ₃ as shown in FIG. 14, eight applied to the scanning electrodes X _l · X ₂ · X ₃ in FIG. 25 The first pulse of the pulse pattern is applied, and at the same time, a signal voltage waveform of a predetermined voltage level corresponding to the number of disagreements between the selection pulse and the display data is applied to each of the signal electrodes Y _{1 to} Y _m in the same manner as in the conventional example. Apply. Then, the selected scan electrodes X ₄ , X ₅ ,
The first pulse of the eight pulse patterns applied in FIG. 25 is applied to X ₆ , and at the same time a signal voltage waveform of a predetermined voltage level is applied to each of the signal electrodes Y _{1 to} Y _m .

This was done for all scan electrodes.
Then again the first scan electrode X_l・ X₂・ X ₃Return to above 8
Applying the second pulse of one pulse pattern
Ku. And for all scan electrodes, the eight pulse patterns
One frame F ends when the turn is applied
It is something.

In the present embodiment as well, since the selection pulse is applied a plurality of times in one frame, particularly eight times in the present embodiment as described above, the non-selection period in each pixel, that is, the off period is further shortened. As in the case of FIG. 3, the on-state is brighter and the off-state is darker so that the contrast can be enhanced and the flicker can be reduced.

Also in the driving method of this embodiment, the drive circuit, scan electrode driver and signal electrode driver similar to those in the first embodiment can be used. in this case,
The calculation of the number of mismatches is performed by the arithmetic circuit 4 in FIG. 4 as in the first embodiment, and the signal converted by the arithmetic circuit 4 is transferred to the signal electrode driver configured as in the fourth embodiment. The signal voltage waveform applied to each signal electrode may be created.

Further, by using the drive circuit as described above, it is possible to easily and surely execute the drive method as described above and to provide a display device having excellent display performance.

The order of issuing the selection pulse in each selection period in this embodiment is arbitrary, and can be appropriately changed in one frame F. Further, in the present embodiment, the eight pulse patterns are divided into eight, one by one, but it is also possible to output a plurality of pulses, for example, two in four times.

(Embodiment 6) As described above, a plurality of (h)
The number of bit word patterns in the case of selecting and driving the scanning electrodes is 2 ^h as described above. For example, when h = 3 in the above example, there are 2 ³ = 8 patterns. . The ON / OFF pattern of the voltage applied to the _three scan electrodes X ₁ , X _2, and X ₃ can be expressed as shown in the following table, with ON being 1 and OFF being 0.

[0137]

[Table 2]

When a voltage waveform applied to each scan electrode is formed based on this, it becomes as shown in FIG. However, the waveform shown in FIG. 6A has variations in frequency, and display unevenness may occur when the waveform is actually used.

Therefore, the arrangement is appropriately changed to eliminate the deviation of the frequency components, which is the waveform of FIG. 25B. This waveform is used in the conventional example of FIG.

However, not only when the waveform as shown in FIG. 15A is used, but also when the waveform as shown in FIG. The number of bit-word patterns increases exponentially, and as a result, each pulse width is inevitably narrowed, which may cause a so-called summary when actually applied to a pixel. When gradation display is performed by modulation, the pulse width becomes narrower, which causes crosstalk.

Therefore, in this embodiment, the waveform of the voltage applied to the scan electrodes is set in the following manner to widen the pulse width.

The waveform of the voltage applied to the scan electrodes is as follows. Each scanning electrode can be distinguished. The frequency components applied to each scan electrode should not differ significantly. It is decided in consideration of the fact that the interchangeability within one frame or several frames is guaranteed.

That is, Natural Binary, Walsh,
The pattern of the applied voltage is appropriately selected from the orthogonal function system such as Hadamard in consideration of the above conditions.

Of these, the above items are absolute conditions.
In order to satisfy the items in particular, it is determined that the voltage waveforms applied to the scan electrodes have different frequency components.

FIG. 1 shows the decision made in consideration of the above requirements.
(C) of FIG. 5, the applied voltage waveform includes different frequency components of X _l : 4 * Δt X ₂ : 4 * Δt, 2 * Δt X ₃ : 2 * Δt.

In FIG. 16, a voltage waveform applied to the scanning electrodes is formed based on the waveform of FIG. 15 (c), and a voltage waveform to the signal electrodes corresponding thereto is formed in the same manner as in the conventional example. FIG. 7 is a waveform diagram of an applied voltage in the case of driving by driving.

While the shortest pulse width is Δt in FIGS. 15 (a) and (b) and the conventional example shown in FIG. 25, the narrowest pulse width is shown in FIGS. 15 (c) and 16. It is 2Δt, and can be doubled. By thus widening the pulse width, it is possible to reduce the influence of waveform summary, reduce crosstalk, and increase the number of scan electrodes selected at the same time. Note that the waveforms in the above embodiments are examples and can be changed appropriately, and the selection order of scan electrodes, the arrangement order of pulse patterns applied to each scan electrode, and the like can be changed arbitrarily.

FIG. 17 shows an example in which the drive waveform of FIG. 16 is applied a plurality of times within one frame F as in the fifth embodiment.

With the above arrangement, the contrast in the on / off state can be enhanced as in the fifth embodiment, and the flicker can be reduced, and the crosstalk due to the waveform waveform can be reduced. Further, the same drive circuit as that of the fifth embodiment can be used, and the same display device can be obtained.

[0150] In Example 7 above embodiment, as the voltage level of the signal electrodes, but using four levels of _{V 3 · V 2 · -V 2} · one V _3, the number of levels following You can reduce it as you like.

First, a general method for reducing the number of voltage levels will be described.

Of the above h subgroups, e lines are set as virtual scanning electrodes (virtual lines), and by controlling the matching / mismatching of the data of the virtual scanning electrodes, the overall matching /
The number of mismatches is limited and the number of drive voltage levels of the signal electrodes is reduced.

When the number of mismatches is Mi and Vc is an appropriate constant, the applied voltage V _column to the signal electrode is

[0154]

[Equation 2]

Alternatively, simply, V _column = V _(i) 0 ≦ i ≦ h In any case, V _column has h 11 levels.

For example, consider the case where the subgroup h = 4 and the virtual scan electrode e = 1.

[0157] The level number in the case of h = 3 as in the above described embodiment, -V _3, a 4-level _{-V 2, V 2, V 3} , an even number of mismatches in the virtual scanning electrodes when the The following table shows the control.

[0158]

[Table 3]

As described above, the original voltage level of 4 steps can be changed to 3 steps. If the number of mismatches is odd, the number of mismatches after correction in the above table becomes 1, 1, 3, and 3 in order from the top, and the voltage level after correction is, for example, Va · Va · Vb · It can be at two levels of Vb.

[0160] Further subgroups at h = 4, the voltage level when no reduced voltage level, for example -V _3, -
While 5 levels of V ₂ , 0, V ₂ and V ₃ are required, if the virtual scan electrodes are controlled so that an even number of mismatches occur,
It becomes like the following table.

[0161]

[Table 4]

As described above, the original voltage level of 5 steps can be changed to 3 steps. Also in the above case, the voltage level can be set so that the number of mismatches becomes an odd number.

The virtual scanning electrode need not be actually provided because it does not normally need to be displayed, but when it is provided, it should be provided in a portion that does not affect the display. For example, in a liquid crystal display device or the like. 18, provisional scanning electrodes X _{n + 1} ... Are provided outside the display region R, as shown in FIG.
Alternatively, if there are extra scan electrodes outside the display region R, they can be used as virtual scan electrodes.

The number of levels can be further reduced by increasing the number e of virtual scanning electrodes. In that case, as described above, when e = 1, the number of mismatches is controlled to be divided by 2, but when e = 2, the number of mismatches is all 3.
You can control it so that it breaks. However, all of them may be divided by 3 to leave 1 or 2 or more.

Further, the maximum reduction number that can be reduced by the above method is 1 / (e + 1), and when e = 1, it is 1/2 except 0V.

In FIG. 19, the voltage level applied to the signal electrode is reduced by sequentially using three scan electrodes and one virtual scan electrode, and the selection period is divided into a plurality of times within one frame for driving. Here is an example.

In the present embodiment, the selection period is divided into four times within one frame, and the number of mismatches is counted for each of the four scan electrodes including the virtual scan electrode, and the number of mismatches is always an odd number. By doing so, the number of mismatches becomes 1 or 3, and accordingly, the voltage level of the signal voltage waveform becomes V ₂ and −.
It has two levels of V ₂ .

Specifically, for example, when the display as shown in FIG. 18 is performed, as shown in FIG. 20, the first selected scan electrode X ₁ , X ₂ , X ₃ is followed by the virtual scan electrode X. _{n + 1}
(In practice, it may not be provided as described above, and if it is provided, it is desirable to provide it outside the display region R as shown in FIG. 10), and the voltage applied to the scanning electrode is positive. With respect to the time t _l with the case of ON being on and the case of minus being OFF, each scan electrode X _l · X ₂ ·
The X _3, the voltage pulse V _l · V _l · -V _l are applied respectively, assuming that V _l is applied to the virtual scanning electrodes X _{n + 1,} then the signal electrodes Y ₁ and the virtual scanning When the data displayed in the pixel at the intersection of the electrodes X _{n + 1} is turned off, the number of mismatches becomes 1, and a voltage pulse of −V ₂ may be applied to the signal electrode.

Next, regarding the period of t ₂ , assuming that V ₁ is applied to the virtual scan electrode X _{n + 1} , the number of mismatches is 3, and the voltage pulse of V ₂ is applied to the signal electrode. Good. Further, assuming that V _l is applied to the virtual scan electrode X _{n + 1} during the period of t _3, the number of mismatches is 3, and the voltage pulse of V ₂ may be applied to the signal electrode. Further, assuming that −V ₁ is applied to the virtual scan electrode X _{n + 1} during the period of t _4, the number of mismatches is 1, and a −V ₂ voltage pulse may be applied to the signal electrode.

In this way, assuming that the polarity of the selection pulse applied to the virtual scan electrode and the display data are set so that the number of mismatches is always an odd number such as 1, 3, ... Is reduced, and the number of levels can be two in the above embodiment. However, the number of mismatches may be an even number as described above. In each period of Fl and F2, the alternating voltage is applied by setting the applied voltage to the opposite polarity.

When the number of levels of the voltage applied to the signal electrode is reduced as described above, the circuit configuration of the liquid crystal driver or the like is simple, and a drive circuit similar to that of the above embodiment can be used. A display device having a good display performance can be obtained as in the above-mentioned embodiment.

INDUSTRIAL APPLICABILITY As described above, the driving method for a liquid crystal element and the like, the driving circuit, and the display device according to the present invention have the above-mentioned configurations, and therefore the following effects can be obtained. 1) Since a plurality of scanning electrodes are sequentially selected at the same time and the selection period is divided into a plurality of times for driving in one frame, as shown in FIG. 3, ON is brighter and OFF. Can be made darker and the contrast can be increased. 2) Since the selection pulse is applied multiple times in one frame, flicker is not noticeable. Further, even if the frame frequency is lowered, there is little flicker, the frame frequency can be lowered, and crosstalk can be reduced. 3) Display can be performed by lowering the driving voltage. 4) Since the frame frequency can be lowered as described above, it is possible to lengthen the pulse width, thereby reducing the crosstalk due to the summary of the waveform and improving the image quality.

As described above, according to the present invention, various effects can be obtained. For example, by applying to various display devices such as a liquid crystal display such as a computer and a word processor, the display quality and reliability can be improved. Is something that can be done.

[Brief description of drawings]

FIG. 1 is a waveform diagram of applied voltage showing an embodiment of a method for driving a liquid crystal element or the like according to the present invention.

FIG. 2 is a plan view showing a schematic configuration of a liquid crystal display or the like.

FIG. 3 is a graph showing a relationship between a voltage applied to a pixel and a transmittance according to an example.

FIG. 4 is a block diagram showing an embodiment of a drive circuit.

FIG. 5 is a block diagram of a scan electrode driver.

FIG. 6 is a block diagram of a signal electrode driver.

FIG. 7 is an applied voltage waveform diagram showing another embodiment of the method for driving a liquid crystal element or the like according to the present invention.

FIG. 8 is an applied voltage waveform diagram showing another embodiment of the method for driving a liquid crystal element or the like according to the present invention.

FIG. 9 is an explanatory diagram of a display pattern.

FIG. 10 is a waveform diagram of a voltage applied to a signal electrode according to a display pattern.

FIG. 11 is an applied voltage waveform diagram showing another embodiment of the method for driving a liquid crystal element or the like according to the present invention.

FIG. 12 is an explanatory diagram of a display pattern.

FIG. 13 (a) is a waveform diagram of voltage applied to scan electrodes,
(B) is a waveform diagram of the voltage applied to the signal electrodes according to the display pattern.

FIG. 14 is an applied voltage waveform diagram showing another embodiment of the method for driving a liquid crystal element or the like according to the present invention.

FIG. 15 is an explanatory diagram showing an example of changing the waveform of the voltage applied to the scan electrodes.

FIG. 16 is an applied voltage waveform diagram in the case of driving by applying a changed scanning voltage.

FIG. 17 is an applied voltage waveform diagram showing another embodiment of the method for driving a liquid crystal element or the like according to the present invention.

FIG. 18 is an explanatory view showing an arrangement example of virtual electrodes.

FIG. 19 is an applied voltage waveform diagram showing another embodiment of the method for driving a liquid crystal element or the like according to the present invention.

FIG. 20 is an explanatory diagram showing a procedure for reducing a signal voltage level by using virtual electrodes.

FIG. 21 is an applied voltage waveform diagram showing an example of a conventional method for driving a liquid crystal element or the like.

FIG. 22 is an explanatory diagram of a display pattern.

FIG. 23 is an applied voltage waveform diagram showing another example of a conventional method of driving a liquid crystal element or the like.

FIG. 24 is an explanatory diagram of a signal voltage waveform applied to a signal electrode according to a display pattern.

FIG. 25 is an applied voltage waveform diagram showing another example of a conventional method for driving a liquid crystal element or the like.

FIG. 26 is an explanatory diagram of a display pattern.

FIG. 27 is a graph showing a relationship between a voltage applied to a pixel and a transmittance according to a conventional example.

Continuation of front page (51) Int.Cl. ⁷ Identification code FI G09G 3/20 622 G09G 3/20 622Q 623 623U 631 631B 641 641E

Claims (3)

(57) [Claims] 1. A method of driving a liquid crystal device, comprising: a plurality of scan electrodes; a plurality of signal electrodes intersecting the plurality of scan electrodes; and a liquid crystal sandwiched between the respective scan electrodes and the respective signal electrodes. The plurality of scan electrodes are divided into subgroups, the scan electrodes in the subgroup are simultaneously selected, and the scan electrodes selected simultaneously are applied with a scan voltage in a plurality of selection periods within one frame. , A plurality of selection periods for applying the scanning voltage are continuously set in one frame without an interval, and the scanning is applied in the plurality of selection periods continuously set in one frame The voltage waveform has a pulse width larger than that of the selection period, has different frequency components from the plurality of simultaneously selected scan electrodes, and has a frequency component different from each other. A number of scanning electrodes are set so as not to be significantly different from each other, and a signal voltage set based on the data to be displayed and the waveform of the scanning voltage is applied to the signal electrodes. Driving method. 2. A liquid crystal device comprising: a plurality of scan electrodes; a plurality of signal electrodes intersecting the plurality of scan electrodes; and a liquid crystal sandwiched between the scan electrodes and the signal electrodes. Scanning electrodes are divided into subgroups, the scanning electrodes in the subgroups are simultaneously selected, and scanning voltages are applied to the scanning electrodes simultaneously selected in a plurality of selection periods within one frame. Waveforms of the scanning voltage applied in the plurality of selection periods that are continuously set in one frame by setting a plurality of selection periods in which a voltage is applied continuously without an interval in one frame Has a pulse width larger than the selection period, the plurality of simultaneously selected scan electrodes have different frequency components, and the frequency component is the same as the plurality of simultaneously selected scan electrodes. The liquid crystal device is characterized in that the signal voltages are set so that they do not significantly differ from each other, and a signal voltage set based on the data to be displayed and the waveform of the scanning voltage is applied to the signal electrodes. 3. A drive circuit of a liquid crystal device, comprising: a plurality of scan electrodes, a plurality of signal electrodes intersecting the plurality of scan electrodes, and a liquid crystal sandwiched between the respective scan electrodes and the respective signal electrodes. The plurality of scan electrodes are divided into subgroups, the scan electrodes in the subgroup are simultaneously selected, and the scan electrodes selected simultaneously are applied with a scan voltage in a plurality of selection periods within one frame. , A plurality of selection periods for applying the scanning voltage are continuously set in one frame without an interval, and the scanning is applied in the plurality of selection periods continuously set in one frame The waveform of the voltage has a pulse width larger than the selection period, has different frequency components from each other among the plurality of simultaneously selected scan electrodes, and the plurality of simultaneously selected frequency components. Driving of a liquid crystal device, characterized in that the scanning electrodes are set so as not to differ greatly from each other, and a signal voltage set based on the data to be displayed and the waveform of the scanning voltage is applied to the signal electrodes. circuit.