JP3513016B2 - Driving method and driving circuit for liquid crystal display 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 method and a driving circuit for driving a liquid crystal display device at high speed.

[0002]

2. Description of the Related Art Conventional twisted nematic (TN)
Alternatively, a driving method called a voltage averaging method has been used for a simple matrix liquid crystal display device such as a super twisted nematic (STN). In this drive method, when the number of scanning lines is N and the frame period is T, T / N is assigned to the selection period and (N-1) T / N is assigned to the non-selection period. That is, in one frame, there is a selection pulse of N present one in the other is made up in composed applied waveform bias wave having a peak value of 1 / b of the selection pulse ON voltage. The applied waveform is shown in A of FIG. The horizontal axis represents time and the vertical axis represents voltage.

[0003]

In this voltage averaging method, it is premised that the liquid crystal behaves as a so-called effective value response, whereby a predetermined contrast ratio can be obtained. The state of the effective value response is shown in C of FIG. The horizontal axis represents time, and the vertical axis represents transmitted light intensity when polarizing plates are arranged on both sides of the liquid crystal layer.

[0004] However, when driving a liquid crystal having a high-speed response as accommodate mice display or video display in the liquid crystal display device used in the terminal, using the driving method described above, the molecular axis of the liquid crystal molecules There for easily follow against voltage, as shown in B of FIG. 5 (b), it will indicate the so-called peak response behavior optical response waveform,
It will deviate from C in the RMS response. That is, the optical response waveform that rises selection period, can not be maintained in the non-selection period, the ratio of the attenuation increases, lower the flat <br/> average level of transmittance, a problem that the contrast ratio is reduced Occurs.

Such a problem is caused by a high duty cycle of hundreds or more.
Although when performing dynamic drive of I will come occurs with flat <br/> average response time of the so-called liquid crystal is below 150 msec, the average response time, particularly in the dynamic drive 100
It is remarkable Oite in the following liquid crystal msec.

Here, the average response time of the liquid crystal in the liquid crystal display device is defined in this specification as follows. That is, sufficient T _OFF light transmittance of time is OFF voltage at the time that has passed, and the light transmittance of the ON voltage T _ON, OF
The time when the F voltage is switched to the ON voltage is t ₁ , and then
The time when the light transmittance T becomes (T _ON −T _OFF ) × 0.9 + T _OFF is t ₂ , the time when the ON voltage is switched to the OFF voltage is t ₃ , and then the light transmittance T is (T _ON −T _OFF − T _OFF )
The average response time τ is represented by τ = ((t ₄ −t ₃ ) + (t ₂ −t ₁ )) / 2, where t ₄ is the time when × 0.1 + T _OFF .

By the way, TNRuckmongathan realizes so-called IH in order to realize driving and display uniformity at a low voltage.
Proposed AT method (1988 International Display R
esearch Conference). The driving method is

The N row electrodes are divided into P (P = N / M) subgroups each consisting of M row electrodes,

For any one column electrode, the data to be displayed for the selected subgroup is [d _{kM + 1} , d
_{kM + 2} ..., d _{kM + M} ]; d _{kM + j} = 0 or 1 (where 0 represents off and 1 represents on; and k represents 0 to (P-1 ) Is displayed in M-bit word,

The selection pattern of the row electrodes is _defined as [a _{kM + 1} , a _{kM + 2} ..., a _{kM + M} ]; a _{kM + j} = 0 or 1 2 ^M (= Q) kinds of M bit words (w ₁ , w ₂ , ...
-When displayed as w _Q ), it is characterized by driving in the following steps.

(1) Select the first row electrode subgroup. (2) Select the first M-bit word w ₁ as the row electrode selection pattern. (3) the selection pattern and the data pattern of the selected sub-group compared for each bit, the sum i of the outputs of these exclusive OR. (4) With respect to the above sum i, the voltage of the column electrode is defined as V _i . (5) V _i independently for each column of the matrix
Choose.

[0012] (6) in the row and column electrodes at the same time, the V _i is the column electrodes, 1st w ₁ (the non-selected row electrodes of the selection pattern of the row electrodes of the row electrodes is grounded, selected The row electrodes are filled with -V _r for 0 and + V _r for 1
And ), And voltage is applied during time T. (7) A new row electrode selection pattern w ₂ is selected, the corresponding column electrode voltage is selected in the same manner as in steps (3) to (5), and the column and row are simultaneously timed as in (6). During T
Apply voltage.

(8) All 2 ^M row electrode selection patterns are selected to complete one cycle. (9) The next row electrode subgroup is selected, and the above (2) is selected.
Continue the cycle of (8).

In particular, if V _i = V ₀ (2i-M) / MV _r = V ₀ N ^1/2 / M is selected, the ON / OFF ratio of the effective voltage value can be maximized.

The ratio of the effective voltage of ON to OFF at this time is V _ON / V _OFF = ((N ^1/2 +1) / (N ^1/2 -1))
^It becomes ^1/2 , which is equal to V _ON / V _OFF in the voltage averaging method used conventionally. Therefore, the contrast becomes the same. Further, since the effective voltage value of each lighting portion in the matrix becomes uniform, uniform display can be obtained regardless of the display pattern.

[0016] IHAT method, when applied to a liquid crystal showing a high-speed response, not necessarily cause the advantage, also,
Such a concept is not shown, and it has nothing to do with the method of driving the liquid crystal display panel at high speed. In particular, the need to drive the liquid crystal display device at high speed arises when displaying a moving image or a screen that switches at high speed.
Therefore, it is necessary to process the display data input one after another at high speed, but there is no description of a configuration suitable for such processing. The present inventor has newly found that a driving method extremely suitable for high-speed driving of a liquid crystal display panel can be obtained by adding a new improvement to this method, and has arrived at the present invention.

[0017]

The present invention has been made to solve the above-mentioned problems, and is a method of driving a liquid crystal display device having column electrodes and N row electrodes arranged in a matrix. N row electrodes are divided into a plurality of sub-groups of M row electrodes (2 ≦ M <N), and row electrodes are selected.
The voltage applied expressed in 1 and 0, all of the row electrodes in one sub-group to be selected, electrostatic represented by 1 and 0
Voltage vectors are applied simultaneously , and the row electrodes in the remaining non-selected subgroups are applied with any voltage of the voltage vectors.
The non-selection voltage which is a different voltage is applied, and the display data
On 1 represents off 0, after writing the sequential M memory area table <br/> display data corresponding to the row electrodes of the M present in every predetermined number of bits, read at the same time, the M present Of the voltage vectors applied to the row electrodes of M and row tables corresponding to the M row electrodes.
The signal to be applied to the column electrode is formed based on the exclusive OR with the indicated data, and the effective voltage value of each lighting portion is changed within one frame.
Each voltage vector changed with time to be uniform
This is a method of driving a liquid crystal display device, in which the voltage is sequentially applied to all subgroups . Hereinafter, a driving method to which the present invention is applied will be described. The driving method basically applies a selection pulse train simultaneously to a plurality of rows of one subgroup,
Further, by sequentially applying to the row electrodes in each sub-group, the row electrodes are selected, and the application of the selection pulse is dispersed within one frame, thereby non-selecting the optical state excited by the selection pulse. This is to reduce the attenuation in the period. As a specific example, N of a matrix liquid crystal display device having N row electrodes and L column electrodes is used.
The row electrodes of the selected collectively P number is divided into sub-groups (1 <P <N) 1 Tsunosa Bed group,

[0018] (a) a set of potential state of a particular subgroup made to include all possible potential state subgroups when to take two kinds of any of the potential line electrodes in a selected state In advance,
The set is divided into a plurality of sub-sets, and (b) all row electrodes belonging to one sub-group are simultaneously
Selected, such that the sub-group is any potential state belonging to one sub-set, potential states of the sub-set to
Are sequentially applied, and (c) step b is performed for all sub-groups, and (d) the sub-sets are changed, and steps b and c are performed for all sub-sets, thereby selecting the row electrodes. You can

That is, as in the IHAT method, one of the row electrodes is
When selecting one subgroup, instead of applying all the selection patterns of the row electrodes together continuously, the subgroup of the selected row electrodes is updated every time several selection patterns of the row selection waveform are applied. However, after selecting all the subgroups of the row electrodes, the method moves to the next selection pattern of the row selection waveform.

The present invention will be described in detail with reference to the embodiment shown in FIG. For simplicity, the number of row electrodes N is set to 400,
Consider dividing this into subgroups of M = 4 each. Therefore, at this time, the number of subgroups P is P as a whole.
= N / M = 100.

[0021] Here, M is a divisor der lever of N, but the row number of electrodes in the subgroup is a configuration preferable for all uniform driving circuit necessarily be rather so, less sub of the number of row electrodes The number of selection patterns for the group is reduced, and there is no particular problem.

As has been proposed by the IHAT method, in order to select a row electrode in units of a subgroup consisting of a plurality of electrodes, it is necessary to change the selection voltage over time rather than keeping it constant. In the basic IHAT method, if the selection voltage is a binary value of + V _r and −V _r, and the number of row electrodes to be selected at the same time is M, the potential states of the possible subgroups (2 ^M types in total) can be obtained. All) are sequentially applied for the subgroup of row electrodes in question. As in this example, it is possible to simplify the actual driving circuit by setting the absolute values of the two kinds of selection voltages to be equal in absolute value and using opposite signs and setting the non-selection voltage to 0 (ground). Moreover, the signal is converted into an alternating current, which is preferable.

In this example, a set of potential states (having 2 ^M or more of elements) including all such potential states is first considered.
For example, when one subgroup consists of four row electrodes as in this example, the potential state that can be taken as a whole is 2 ⁴
= 16 types exist. In this case, the set of potential states of the row electrodes has 16 or more elements.

It is simple and preferable to set the number of elements to 2 ^M (that is, all the potential states appear once). However, in terms of drive timing, the same states can be overlapped as elements, or the above selection can be made. It is also possible to add a state other than the state in which the voltage can be binary. In any case,
In order to complete the selection of one subgroup, all the potential states that can take the selection voltage as binary must be applied to the subgroup of the row electrode. For simplicity, the number of elements in the set of potential states is 2 ⁴ = 16 for M = 4 for simplicity.
I mainly think about the case.

This set is shown in Table 1 as + V _r → 1, -V _r → 0, and the four row electrodes as a ₁ , a ₂ , a ₃ and a ₄ .

[0026]

[Table 1]

In this example, specifically, (1) such a set of potential states of subgroups of row electrodes is divided into a plurality of subsets, and (2) row electrodes belonging to one subgroup are A voltage is applied simultaneously in a batch so that the subgroups are in all potential states belonging to one subset, and (3) the second step is performed for all the row electrode subgroups. Row electrodes are selected by performing steps 2 and 3 for all sub-sets. This makes it possible to disperse the application of the selection pulse within one frame and reduce the attenuation of the optical state excited by the selection pulse in the non-selection period.

Regarding the method of dividing the set of potential states of the sub-group of row electrodes into a plurality of sub-sets, it is not necessary to make the number of elements of the sub-set uniform, but the number of elements of the set of potential states is 2 If there are ^M, 2 ^Mj ( ^0≤j
It is preferable for forming the driving circuit to form a sub-set having 2 ^j elements of ≦ M−1). However, since the selection pulses are distributed by the number of the sub-sets during the period of selecting one screen once, the number of the sub-sets should be large, and the most preferable one is j = 0, that is, the sub-sets. This is the case where the number of elements in the set is 1.

The case where j = 0 is described below.

The order of applying the individual potential states in the set of potential states is arbitrary. For example, if the voltages are applied in the order shown in Table 1, the natural binary system will be used. Alternatively, a random code or a gray code can be adopted.

It is also possible to use a frequency equalizing code in which the frequencies of the selected waveforms are equal for all the row electrodes in the row electrode subgroup. Table 2 shows an example of the case of M = 4.

[0032]

[Table 2]

Hereinafter, each of the potential states represented by 1, 0 will be referred to as a selection pattern. The selection pattern will be M.
Can be expressed in bit words. When selecting in the order of natural binary, in the example of FIG. 2, the selection pattern can be expressed by a 4-bit word, and (a
₁ , a ₂ , a ₃ , a ₄ ) = (0,0,0,0) → (1,
0,0,0) → (0,1,0,0) → −−− → (1,
It will change from 1, 1, 1). Then, for each selection pattern, the voltage for all sub-groups is applied, then it moves to the next selection pattern. In this case, 4 in the sub-group of the top row electrode in FIG.
FIG. 1 shows a time series change of the potentials of the row electrodes R _{1 to} R ₄ of the book.

By doing so, the selection pulses, which were conventionally arranged at a ratio of 1 to N as shown in FIG. 5, are dispersed at a ratio of 1 to N / M. Therefore, the non-selection period until the next selection pulse rises is shorter than that in the conventional voltage averaging method, and the degree of optical change is reduced, which contributes to prevention of deterioration in brightness and contrast.

The voltage to be applied to the column electrodes in this case will be described below. When a display pattern as shown in FIG. 2 is displayed, the data pattern corresponding to this is as shown in the table in the figure when ON is 1 and OFF is 0.
The column electrodes of the respective sub-group, which we divided into data pattern for each M bits (in FIG. 2 4 bits). For example, in the column electrode C ₉ , (d ₁ , d ₂ , d ₃ , d ₄ ) =
(1,0,1,0). In order to determine the voltage to be applied to each column electrode when one subgroup of the row electrode is in the potential state of Table 1, the 4-bit word of the selection pattern of the row electrode and the data of the corresponding column electrode. Exclusive-OR with the 4-bit word of the pattern.

For example, suppose that the voltage to be applied to the column electrode C ₉ of FIG. 2 is determined when the first subgroup of row electrodes of FIG. 2 is in the first potential state of Table 1. At this time, the exclusive OR i is expressed by Equation 1. It should be noted that the bar of the superscript in the number 1 to the table sum "negative".

[0037]

[Equation 1]

The voltage V _i applied to the column electrode when the exclusive OR becomes i may be determined as follows, for example.
The obtained exclusive OR is (M + 1) types (M = 4 above).
There are 5 types), and these are V _M , V _M-1 , ...
If V _i ..., V ₀ , then V ₀ <V ₁ <V ₂ ... <V
_i <... V _M-1 <V _M or V ₀ > V ₁ >...> V _i
>...> V _M-1 > V _M. In the following, for the sake of _{convenience, V 0 <V 1 <V} 2 ··· <V i <···
The case where V _M-1 <V _M is described.

For example, when the selection patterns shown in Table 1 are used and the display pattern of FIG. 2 is displayed, the voltages applied to the column electrodes C ₁ , C ₂ , C ₃ and C ₉ are as shown in FIG. Like In the figure, for example, R _{1 to} R ₄ are R _{1 to} R ₄
Shows the voltage change for the period in which the subgroup of row electrodes is selected. Here, R _{1 to} R ₄ , R _{5 to} R
₈ , R _{9 to} R ₁₂ are drawn independently. For ease of viewing, the time axis of the horizontal axis is different from that of other subgroups.
The selection period is omitted. Further, according to the present invention, when the selection pulse is dispersed and applied (for example, when j = 0 where the number of elements of the sub-set is 1), the voltage application shown in the graph is continuously performed. Instead, after one voltage is applied on the graph,
Voltage application to other subgroups is performed, after the time of voltage application to another subgroup has elapsed, the next voltage application on the graph is performed.

In practice, V _i should be selected so that V _i = V _c (2i−M) / M is approximated, where V _c is the maximum value of the column electrode voltage, in order to simplify the drive circuit. preferable.
Under the above conditions, the maximum value of V _i is V _c , and the interval between V _i and V _i-1 is constant at 2V _c / M regardless of i.

Under such conditions, the selection voltage V _r = V _c
It is the same as in the case of the IHAT method, that when selected near N ^1/2 / M, the effective voltage value V _ON / V _OFF is maximized and is equal to V _ON / V _OFF in the voltage averaging method. However, since sometimes it becomes an intermediate state between the peak value response and effective value response depending on the characteristics of the liquid crystal, necessarily the V _r
In some cases, it may be preferable to adjust in the vicinity of ^R _c , not to select V _c N ^1/2 / M accurately.

When M = 4 as shown in FIG. 2, V ₄ = + V
_{c, V 3 = + V c} / 2, V 2 = 0, V 1 = -V c / 2,
Select V ₀ = -V _c or the like. Also, V _r = 5 V _c .
In this case, R ₁ -C ₉ (ON state) and R ₂ -C in FIG.
FIG. 4 shows the voltage change in ₉ (OFF state). However, for ease of viewing, the horizontal time axis is drawn with the 99 lines in the non-selected state in FIG. 1 omitted.

In the conventional voltage averaging method, as shown in FIG. 5, selection pulses are arranged at a ratio of one to N.

Therefore, when applied to the fast response liquid crystal , the non-selection period is longer than the response time (decay time) of the liquid crystal, so that the optical state excited by one selection pulse is
As the speed increases as it decays during the non-selected period,
The degree of damping also increases. Therefore, the brightness at the time of ON is lowered and the contrast is also lowered.

[0045] In contrast, in the present invention, because they are dispersed at a ratio of one selection pulse to N / M present, a non-selection period to stand next selection pulse, the voltage averaging This is shorter than that of the method, and the degree of change in the optical state is reduced, which is considered to contribute to the prevention of deterioration in brightness and contrast.

An example of a circuit adopted to realize the present invention is shown in FIG. The LCD panel has N row electrodes and L
The column electrodes are arranged in a matrix , and the N row electrodes are divided into subgroups of M row electrodes as described above, and the subgroups are collectively selected. Further, as display data, α-bit parallel data is transferred and displayed.

The selection signal formation was performed as follows. First, a pulse train serving as a reference is generated by the pulse generator 1 and input to the clock of the column address counter 2. The pulse train divided by the column address counter 2 to 1 / α is input as the clock signal 4 to the clock of the L / α stage shift register 15. In addition, α /
The load signal 5 divided into L is used as the clock of the subgroup counter 6, the clock of the flip-flop 7, the load of the L / α bit latch 16, the clock of the M N / M stage shift registers 18, and 1 It is input to the clock of the N / M stage shift register 19 of. Where L / α
The stage shift register 15 and the L / α bit latch 16 are
If g is a natural number that satisfies 2 ^g-1 <M + 1 ≦ 2 ^g , then g
× α pieces are required.

Further, the load signal 5 is divided into M / N by the subgroup counter and input to the data of the flip-flop 7, and the output of the flip-flop 7 is used as a frame signal 8 for the clock of the row stage counter 9 and one N / M
Input to the data of the stage shift register 19. The M-bit output of the row stage counter 9 is directly input or converted into a gray code or the like and input to the data of the M N / M-stage shift registers 18, respectively.

The outputs of the M N / M stage shift registers 18 and the output of one N / M stage shift register 19 are input to the N-bit 3-level driver 20, and the N outputs of the 3-level driver 20 are output. Input to the row electrodes of the liquid crystal panel 21.

Further, ON / OFF corresponding to display data
Signal formation was performed as follows. The display data 10 is
For M ・ k + 1 lines, M ・ k + 2 lines, ..., M ・ k +
M RAMs 1 for M rows (k = 0, ... N / M-1)
1, 11, ..., 11 are sequentially written as α-bit data, and the output of the column address counter 2 is used as a RAM address 3 for these M RAMs.
, 11 are input in parallel for addressing.

The α-bit display data is stored in M RAMs 1
, 11, ... Simultaneously read from the row stage counter 9 and α exclusive OR formation with the corresponding rows of the row stage counter 9 and exclusive OR with the adder 14 and addition to obtain a g-bit result And The result is input to the data of the L / α stage shift register 15, and is sequentially shifted by the clock signal 4, and when all the data of the L / α stage are completed, the parallel output is sent to the L / α bit latch 16 and the load signal 5 Memory in. The output of the L / α bit latch 16 is input to L (M + 1) level drivers 17,
The L outputs of the (M + 1) level driver 17 are input to the column electrodes of the liquid crystal panel 21, respectively. As described above, according to the present invention, the display data on the M row electrodes that are simultaneously selected are sequentially written into the M memory areas, and then simultaneously read to display the display data (logical value) and the corresponding row. The signal to be applied to the column electrode is formed based on the exclusive OR with the voltage vector (logical value) applied on the electrode. As described above, in the driving method of the liquid crystal display device in which a plurality of row electrodes are selected at the same time, a plurality of display data on the plurality of row electrodes are used for the calculation for determining the voltage on the column electrodes. Therefore, as described above, the display data on the M row electrodes that are simultaneously selected is sequentially written into the M memory areas, and then the simultaneous reading operations are performed, so that the display data that is input one after another can be efficiently input. It is possible to calculate well at high speed.

[0052]

(Embodiment 1) An average response time of 80 msec using the above circuit configuration.
A liquid crystal display device provided with STN liquid crystal of (25 ° C.) is N = 2.
40, M = 4, frame frequency (which means a frequency for scanning one screen. The same applies to the embodiment and the IHAT method) 90
When driven by the driving method of the present invention at Hz, the maximum contrast ratio was 80: 1.

At this time, j = 0 (that is, the number of elements in the sub-set is 1), and the frequency equalizing code as shown in Table 2 is used for the order of selecting individual potential states from the set of potential states. Using. Furthermore, V _i = V _c (2i−M) /
M and V _r = V _c N ^1/2 / M were selected, and the absolute value of the voltage was adjusted so that the maximum contrast ratio was obtained.

(Comparative Example 1) The conventional voltage averaging method was used in a 1/240 duty ratio and a 1/1.
5 bias ratio, liquid crystal display similar with a frame frequency 90Hz
When the display device was driven, the maximum contrast ratio was 47:
It was 1.

(Comparative example 2) N = 240, M = 4, frame frequency 90 by IHAT method
When driven at Hz, the maximum contrast ratio was 30:
Became 1.

(Embodiment 2) In the driving method of the present invention, the same liquid crystal display device as in Embodiment 1 was driven in the same manner except that the pulse width was 12 μsec instead of defining the frame frequency as 90 Hz. The contrast ratio was 75: 1.

(Comparative Example 3) The liquid crystal display device of Example 2 with a duty ratio of 1/240, a bias ratio of 1/15 and a pulse width of 12 µsec by the conventional driving method.
When the apparatus was driven, the maximum contrast ratio was 55: 1.

(Embodiment 3) Using the above circuit configuration, the average response time is 45 msec.
A liquid crystal display device provided with STN liquid crystal of (25 ° C.) is N = 2.
When driven by the driving method of the present invention with 40, M = 3 and a frame frequency of 90 Hz, the maximum contrast ratio was 3
It became 0: 1.

In this case, j = 0 (that is, the number of elements in the sub-set is 1), and the order of selecting individual potential states from the set of potential states is the natural binary code of the order shown in Table 1. Was used. Further, as in Examples 1 and 2, V
_i = V _c (2i−M) / M and Vr = V _c N ^1/2 / M were selected, and the absolute value of the voltage was adjusted so that the maximum contrast ratio was obtained.

(Comparative Example 4) With the conventional voltage averaging method, the duty ratio is 1/240, 1/1
The liquid of Example 3 with a bias ratio of 5 and a frame frequency of 90 Hz.
The maximum contrast ratio is 1 when the crystal display device is driven.
It became 8: 1.

[0061]

According to the present invention, there is an effect that the calculation for determining the voltage on the column electrode, which is necessary in the driving method for simultaneously selecting a plurality of row electrodes, can be efficiently performed. In addition , by distributing a plurality of selection pulses in one frame, the optical averaging method in the conventional simple matrix method has an optical comparison with one selection pulse in one frame. It has become possible to suppress changes in the state to a small extent. This is effective in driving a liquid crystal display device having a liquid crystal whose average response time during dynamic driving is 100 msec or less, and particularly 50 msec or less.

Since the present invention basically makes use of the characteristics of the IHAT method, if M ≧ 4, the supply voltage can be reduced as compared with the conventional voltage averaging method. ing.

In this case, the supply voltage is further reduced as M is increased, but if the number of M is large, the number of levels (M + 1) of the waveform applied to the column electrode also increases and the hardware becomes complicated. So far, M = 3-4 is preferable.

[0064] Further, a row selection pattern as natural binary, Comparing the frequency component of the driving waveforms of IHAT method and the present invention, in the case of the IH AT method, the first row in the same subgroup and M-th row In the present invention, the frequency component of the selection pulse does not change in any row and any column, whereas the frequency component of the selection pulse is significantly different in the liquid crystal display device having a large frequency dependency of the threshold voltage. A uniform display can be obtained.

Similarly, with respect to the display uniformity by driving, the effect is large as compared with the conventional voltage averaging method.

In the conventional method, the frequency component of the drive waveform greatly varies depending on the display pattern, which causes display unevenness. However, in the present invention, the variation in frequency component due to the display pattern is small, and thus display unevenness occurs. Considered difficult.

[Brief description of drawings]

FIG. 1 is a graph showing a time-series change in potential for row electrode subgroups R _{1 to} R ₄ .

FIG. 2 is a conceptual diagram showing a display pattern of a liquid crystal display device .

FIG. 3 shows column electrodes C ₁ , C ₂ and C in the display pattern of FIG.
_3, a graph showing the voltage applied to C _9.

FIG. 4 shows R ₁ -C ₉ and R ₂ -C in the display pattern of FIG.
_The graph which shows the voltage of ₉ .

FIG. 5 is a graph showing an effective value response and a peak value response.

FIG. 6 is a block diagram showing an example of a circuit that realizes the driving method of the present invention.

[Explanation of symbols]

1: Pulse generator 2: Column address counter 3: RAM address 4: Clock signal 5: Load signal 6: Subgroup counter 7: Flip-flop 8: Frame signal 9: Row stage counter 10: Display data 11: RAM 14: Exclusive Logical OR formation and adder 15: L / α stage shift register 16: L / α stage bit latch 17: ( M + 1 ) level driver 18: N / M stage shift register 19: N / M stage shift register 20: 3 levels Driver 21: LCD panel

Front page continued (72) Inventor Takeshi Kuwata 1160 Hazawa-machi, Kanagawa-ku, Yokohama, Kanagawa Prefecture Asahi Glass Electronic Product Development Center (72) Inventor Yutaka Nakagawa 1160, Hazawa-machi, Kanagawa-ku, Yokohama, Asahi Glass Electronics Co., Ltd. Product Development Center (72) Inventor Hidemasa Taka 1160 Hazawa-machi, Kanagawa-ku, Yokohama, Kanagawa Prefecture Asahi Glass Electronic Product Development Center (72) Inventor Takashi Yamashita 1150, Hazawa-machi, Kanagawa-ku, Yokohama Asahi Glass Co., Ltd. Central Research Laboratory (56) Reference JP-A-5-100642 (JP, A) JP-A-56-130795 (JP, A) JP-A-51-56118 (JP, A) JP-A-56-138789 (JP, A) JP 54-45600 (JP, A) T.I. N. RUCKMONGTHAN, A GENERALIZED ADDR ESSING TECHNIQUE FOR FRON RMS RESPONDING MATRIX LCDS, CONFER ENCE RECORD OF THE THE 1988 INTERNATION DISPAYC ONE RESEARCH FEATURES 18th 1988. 80-85 JURGEN NEHRING, Ultimate Limits for Matrix Addressing of RMS-Responding Liquid-Crystal Di displays, IEEE TRANSA, 1979, ELECTRONE USA. ED-26, NO. 5, p. 795-802 (58) Fields investigated (Int.Cl. ⁷ , DB name) G09G 3/00-3/38 G02F 1/133 505-580

Claims (9)

(57) [Claims] 1. Column electrodes arranged in a matrix and N row electrodes.
A method of driving a liquid crystal display device having a pole, comprising:
The row electrodes are a plurality of sub electrodes each including M (2 ≦ M <N) row electrodes.
Divide into groupsThe voltage applied to the row electrode when selected is 1
And 0, select All row electrodes in one subgroupHas
The voltage vectors represented by 1 and 0 are applied at the same time, The remaining row electrodes in the unselected subgroupThe voltage
A voltage that is different from any voltage in the vectorNon-selective power
Apply pressure,Display data on is 1 and off is 0, M Book row electrodesCorresponding toDisplay dataEvery predetermined number of bits
ToAfter writing sequentially to M memory areas, read simultaneously.
ThenThe M Applied on the row electrodes of the bookVoltage vector and the M lines
Display data corresponding to the row electrodes ofBased on exclusive OR with
Signal to be applied to the column electrodesEach within one frame
It changes with time so that the effective voltage value of the lighting part becomes uniform.
Apply each applied voltage vector to all subgroups sequentially
A method for driving a liquid crystal display device. 2. The method of driving a liquid crystal display device according to claim 1, wherein M is a divisor of N. 3. The method for driving a liquid crystal display device according to claim 1, wherein M = 3. 4. The method of driving a liquid crystal display device according to claim 1, wherein M = 4. 5. A liquid crystal having a response time of 150 ms or less is a liquid.
The method for driving a liquid crystal display device according to claim 1, which is provided in a crystal display device. 6. The method for driving a liquid crystal display device according to claim 1, wherein the order of applying the voltage vector is a natural binary order. 7. The method of driving a liquid crystal display device according to claim 1, wherein the order of applying the voltage vector is the order of uniform frequency code. 8. The M RAMs are arranged as M memory areas, the display data on the M row electrodes are written into the M RAMs, and then read simultaneously from the M RAMs.
8. A method for driving a liquid crystal display device according to any one of items 7 to 7. 9. A drive circuit for a liquid crystal display device, comprising a column electrode driver and a row electrode driver, for carrying out the method for driving a liquid crystal display device according to claim 1, wherein A driving circuit in which the row electrode driver is a 3-level driver having N outputs and the column electrode driver is a (M + 1) level driver having L outputs, where L is the number of outputs.