JPH0792564B2 - Driving method of display device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving method of a display device using a ferroelectric liquid crystal.

2. Description of the Related Art FIG. 4 is a sectional view showing a schematic configuration of a simple matrix panel in which a ferroelectric liquid crystal is sealed.

In FIG. 4, two glass plates 1a and 1b are arranged so as to face each other, and one glass plate 1a is the other glass plate.
A plurality of signal electrodes S (4 here) are provided on the surface facing 1b.
Main) are arranged in parallel with each other, and these signal electrodes S are covered with a transparent insulating layer 2a. A plurality of (four in this case) scanning electrodes L are arranged in parallel with each other on the surface of the other glass plate 1b facing the signal electrode S, and these scanning electrodes L are covered with a transparent insulating layer 2b. There is.

FIG. 5 is a plan view showing an arrangement configuration of the signal electrodes S and the scanning electrodes L described above, and the scanning electrodes L are arranged to intersect the signal electrodes S vertically.

In FIG. 4, alignment films 3a and 3b are formed on the insulating layers 2a and 2b by a process such as rubbing, and the ferroelectric liquid crystal 4 is formed in the space sandwiched between the upper and lower alignment films 3a and 3b.
Are interposed, and this is sealed with the sealant 5.
The above-mentioned insulating layers 2a and 2b are for protecting the sealed ferroelectric liquid crystal 4, and the alignment films 3a and 3b are for aligning the molecules of the ferroelectric liquid crystal 4 in a certain direction. . Polarizing plates 6a and 6b are laminated on the other surface of each glass plate 1a and 1b, and the polarizing axes of these polarizing plates 6a and 6b are deviated from each other by 90 degrees.

4 × 4 configured in this way (the previous numerical value indicates the number of scanning electrodes L, and the subsequent numerical value indicates the number of signal electrodes S)
In the simple matrix panel, the ferroelectric liquid crystal 4 interposed at the intersections of the signal electrodes S and the scanning electrodes L becomes the pixels A11 to A44, as shown in FIG. Here, the scan electrode L
Are sequentially represented from the top as L1, L2, L3, L4, and the signal electrodes S are sequentially represented as S1, S2, S3, S4 from the left, and each scan electrode Li (i = 1, 2,
Pixels in the portion where (3, 4) and each signal electrode Sj (j = 1, 2, 3, 4) overlap are represented as Aij.

FIG. 6 shows a waveform diagram when the above-mentioned 4 × 4 simple matrix panel is driven by a conventional driving method. 6 (1) to 6 (4) show voltage waveforms applied to the scan electrodes L1 to L4, and FIGS. 6 (5) and 6 (6) show voltage waveforms applied to the signal electrodes S1 and S2, respectively. Show. Also,
FIG. 6 (7) shows the effective voltage applied to the pixel A11 (scan electrode L1
Applied voltage V _{L1 −voltage} applied to signal electrode S 1 V _S1 ). Here, the amount of reflected or transmitted light of pixel A11 is controlled to maintain the display state in a dark state (off state). Indicates. Further, FIG. 6 (8) shows the waveform of the effective voltage applied to the pixel A12 (the applied voltage V _L1 to the scan electrode L1−the applied voltage V S2 to the signal electrode _S2 ). Here, the display state of the pixel A12 is shown. The case where it is held in the state (on state) is shown.

In the voltage waveform V _L1 applied to the scan electrode L1 shown in FIG. 6 (1), the waveform of the section ₀ to t ₀ is the pixel A1 on the scan electrode L1.
It is the selection voltage waveform A that can rewrite the display state of 1, A12, A13, A14, and t ₀ 〜2t ₀ , 2t ₀ 〜3t ₀ , 3t ₀ 〜
The waveform in each section of 4t ₀ is the non-selection voltage waveform B in which the display state of the pixel cannot be rewritten. When the period of one frame, that is, ₀ to 4t ₀ has elapsed, the selection voltage waveform A is applied to the scan electrode L1 again in the next section 4t _{0 to} 5t ₀ .

On the other hand, the voltage waveform applied to the scan electrode L2 shown in FIG. 6 (2)
V _L2 is a waveform obtained by delaying the voltage waveform V _L1 applied to the scan electrode L1 by t ₀ , and the selection voltage waveform A is applied in the interval from t _{0 to} 2t ₀ . Further, the voltage waveform V _L3 applied to the scan electrode L3 shown in FIG. 6C is a waveform obtained by delaying the voltage voltage V _L2 applied to the scan electrode _L2 by t ₀ , and the selection voltage waveform A is 2t ₀ ~. It is applied in the interval of 3t ₀ . Further, the scanning electrode shown in FIG. 6 (4)
The applied voltage waveform V _{L4 to L4} is a waveform obtained by delaying the applied voltage waveform V _L3 to the scan electrode _L3 by t ₀ , and the selection voltage waveform A is 3
It is applied in the interval from t _{0 to} 4t ₀ .

That is, the selection voltage waveform A is applied to the scan electrodes L1, L2, L3, and L4 in line order thereof, and when the selection voltage waveform A is applied to one scan electrode L, the remaining scan electrodes L are applied. A non-selected voltage waveform B is applied to.

In the voltage waveform V _S1 applied to the signal electrode S1 shown in FIG. 6 (5), the waveforms in the sections ₀ to t ₀ , t _{0 to} 2t ₀ , 4t _{0 to} 5t ₀ are the pixels A11 and A21 on the signal electrode S1. state display state dark and dark signal voltage waveform F to the (oFF state), the interval 2t ₀ to 3
The waveforms t ₀ , 3t _{0 to} 4t ₀ are bright signal voltage waveforms E for setting the display state of the pixels A31, A41 to the bright state (ON state). On the other hand, in the voltage waveform V _S2 applied to the signal electrode S2 shown in FIG. 6 (6), conversely, the sections ₀ to t ₀ , t _{0 to} 2t ₀ , 4t _{0 to} 5t ₀ are the bright signal voltage waveform E. Therefore, the sections 2t _{0 to} 3t ₀ and 3t _{0 to} 4t ₀ have the dark signal voltage waveform F.

In this way, the effective voltages V _L1 −V _S1 and V _L1 −V _S2 shown in FIGS. 6 (7) and 6 (8) are applied to the pixels A11 and A12.
Is applied.

FIG. 7 is a waveform diagram showing the relationship between the effective voltage applied to the pixel and the reflected or transmitted light amount of the pixel. Of which
FIG. 7 (1) shows the effective voltage V _L1 −V _S1 applied to the pixel A11.
The waveform (same as FIG. 6 (7)) is shown, and FIG. 7 (2) shows the change in the reflected or transmitted light amount of the pixel A11 at this time. Further, FIG. 7 (3) shows the waveform of the effective voltage V _L1 −V _S2 (same as that of FIG. 6 (8)) applied to the pixel A12.
FIG. 4 (4) shows changes in the amount of reflected or transmitted light of the pixel A12 at this time.

As is apparent from FIG. 7, when the dark signal voltage waveform F is applied to the signal electrode S1 and the bright signal voltage waveform E is applied to the signal electrode S2, the selection voltage waveform A is applied to the scan electrode L1. , A very large displacement of the light quantity is observed in the pixels A11 and A12, and the cycle Ta = 4 from the application of the selection voltage waveform A to the scanning electrode L1 to the application of the selection voltage waveform A again
At × t ₀ , a strong light amount is generated in the pixels A11 and A12.

Here, the case of driving a 4 × 4 simple matrix panel is shown, so the above-mentioned cycle Ta is 4 × t ₀ , but in the case of driving an M × N simple matrix panel, M × N is generally used. In the period Ta of t ₀ , the pixel repeatedly generates a strong light amount.

Problems to be Solved by the Invention As described above, when an M × N simple matrix panel is driven by a conventional driving method, a strong light amount is repeatedly generated at a cycle Ta = M × t ₀ , but human vision has a frequency of 60 Hz. Since it is considered to be a low band pass filter of When a large amount of light is repeatedly generated in the period of, this is perceived as flicker and the display quality is degraded.

Assuming that the minimum time width of the unit applied voltage waveform required to rewrite the memory state of the ferroelectric liquid crystal is t _m (seconds), four unit applied voltage waveforms are assigned to one section t ₀ in the above conventional example. Therefore, t ₀ = 4 × t _m (seconds) (2) is required for one section t ₀ , and therefore the above-mentioned cycle Ta is Ta = 4 × M × t _m (seconds) (3) ). At this time, in order to prevent flicker from being detected, 1 / (4 × M × t _m )> 60 (Hz) (4) That is, t _m <1 / (240 × M) (sec) (5) ) Must be met. That is, this condition is, for example, to drive a simple matrix panel of M = 400 (the number of scanning electrodes is 400), t _m <1 / (240 × 400) ≈10 (μsec) (6) It means that we have to develop the ferroelectric liquid crystal material. Conversely speaking, for example, t _m = 100 (μ
When a simple matrix panel of M = 400 using a ferroelectric liquid crystal material of (sec) is driven by the conventional driving method, a strong light quantity is obtained at a cycle Ta = 4 × M × t _m = 0.16 (sec) (7) It is repeatedly generated, and this is felt as flicker, and the display quality is significantly deteriorated.

Therefore, an object of the present invention is to provide a display device driving method capable of driving a display device using a ferroelectric liquid crystal without causing strong flicker.

Means for Solving the Problems The present invention interposes a ferroelectric liquid crystal between a plurality of scanning electrodes and a plurality of signal electrodes arranged in directions intersecting with each other,
The ferroelectric liquid crystal at the intersection of the scanning electrode and the signal electrode is used as each pixel, and a signal voltage waveform corresponding to display data is applied to the signal electrode while the display state of the pixel on the electrode is applied to the scanning electrode. A rewritable selection voltage waveform is line-sequentially applied, and the pixel is applied at a timing when the selection voltage waveform is applied to another scan electrode until one selection frame applies the selection voltage waveform again to the same scan electrode. In the method for driving a display device in which a non-selection voltage waveform whose display state is not rewritable is repeatedly applied, as the non-selection voltage waveform, a basic non-selection voltage waveform and a specific non-selection voltage waveform, With the signal voltage waveform applied to the signal electrode, when the basic non-selected voltage waveform is applied to the scan electrode, the amount of reflected or transmitted light of the pixel on the scan electrode changes. When a specific non-selective voltage waveform is applied to the same scan electrode, the displacement amount that changes the amount of reflected or transmitted light of the pixel on that scan electrode is set to be larger than Then, in the period in which the selection voltage waveform is sequentially applied to the other scan electrodes,
Of multiple non-selective voltage waveform application timings with a period of about 20 ms or less, all non-selective voltage waveform application at a single timing immediately after the selective voltage waveform is applied, or before and after the selective voltage waveform is applied. A method of driving a display device, characterized in that the application is performed at a plurality of non-selection voltage waveform application timings less than the number of timings, while a basic non-selection voltage waveform is applied at other non-selection voltage waveform application timings. Is.

Operation According to the present invention, one frame period that occurs when the state in which the non-selection voltage waveform is applied to the scan electrode is switched to the state in which the selection voltage waveform is applied by the specific non-selection voltage waveform applied to the scan electrode The displacement of the reflected or transmitted light amount of the pixel, which is smaller than the displacement of the reflected or transmitted light amount of the pixel, repeatedly occurs at a cycle of about 20 msec or less during the period of one frame. Is reduced due to the luminance displacement that occurs in a cycle of about 20 msec or less.

Example FIG. 3 is a schematic diagram showing an electrode array configuration of a simple matrix panel having 256 scanning electrodes using a ferroelectric liquid crystal to which a driving method according to an example of the present invention is applied. In the figure, the scan electrodes are sequentially represented as L1, L2, ..., Li, ..., L256 from the top, and the signal electrodes are sequentially represented as S1, S2, ..., Sj, ... from the left, and the scan electrodes Li (i = 1,2 , ...) and the signal electrode Sj (j = 1,2,
Pixels in the overlapping portion are represented by Aij.

FIG. 1 shows a waveform diagram when the above simple matrix panel is driven by the driving method of this embodiment. Of which, the first
FIGS. 1 (1) and 2 (2) show voltage waveforms applied to the scanning electrodes L1 and L2, respectively, and FIGS. 1 (3) and 1 (4) show voltage waveforms applied to the signal electrodes S1 and S2, respectively. Further, FIG. 1 (5) shows the voltage V _L1 applied to the scan electrode _L1 and the signal electrode S1.
Difference voltage V _L1 −V _{S1 of} the voltage V _S1 applied to
Shows the waveform of such an effective voltage, FIG. 1 (6) the difference between voltages V _L1 -V _S2 of the voltage V _S2, is applied to the voltage V _L1 and the signal electrode S2, it is applied to the scanning electrodes L1, that is, the pixel A12 The waveform of such an effective voltage is shown.

FIG. 2 is a waveform diagram in which the waveforms for each section t _{1 of the} waveform diagram shown in FIG. 1 are classified and shown. Of which, Figure 2 (1)
The waveform shown in FIG. 2 is a selection voltage waveform A that is applied to the scan electrode Li and can rewrite the display state of the pixel Aij on the scan electrode Li. The waveform shown in FIG. 2B is applied to the scan electrode Li. However, the basic non-selection voltage waveform B in which the display state of the pixel Aij on the scan electrode Li cannot be rewritten
Is. The waveform shown in FIG. 2 (3) is a specific non-selected voltage waveform C.

The waveform shown in FIG. 2 (4) is the dark signal voltage waveform F applied to the signal electrode Sj to turn the display state of the pixel Aij on the signal electrode Sj into the dark state (off state). The waveform shown in (5) is a bright signal voltage waveform E which is also applied to the signal electrode Sj to bring the display state of the pixel Aij on the signal electrode Sj into the bright state (ON state).

2 (6) to (11) show the waveform of the effective voltage applied to the pixel Aij, of which the waveform A-F in FIG. 2 (6) is the selection voltage waveform A applied to the scan electrode Li and the signal electrode Sj. A waveform when the dark signal voltage waveform F is applied is shown in FIG. 2, and the waveform AE in FIG. 2 (7) shows that the selection voltage waveform A is applied to the scan electrode Li and the bright signal voltage waveform E is applied to the signal electrode Sj. The waveform when applied is shown.

The waveform B-F in FIG. 2 (8) has a basic non-selection voltage waveform B applied to the scanning electrode Li and a dark signal voltage waveform F on the signal electrode Sj.
Shows the waveform when the voltage is applied, and the waveform B in FIG. 2 (9)
-E shows a waveform when the basic non-selected voltage waveform B is applied to the scan electrode Li and the bright signal voltage waveform E is applied to the signal electrode Sj.

In the waveform C-F of FIG. 2 (10), a specific non-selective voltage waveform C is applied to the scan electrode Li and the dark signal voltage waveform F is applied to the signal electrode Sj.
Shows the waveform when a voltage is applied, and the waveform C in Fig. 2 (11)
-E shows a waveform when a specific non-selected voltage waveform C is applied to the scan electrode Li and a bright signal voltage waveform E is applied to the signal electrode Sj.

Waveform B-F in FIG. 2 (8) and waveform C-F in FIG. 2 (10)
As is clear from the comparison with the waveform of FIG. 2 (9) and the waveform of FIG. 2 (11) with the waveform of FIG.
Pixel Ai when a specific non-selective voltage waveform C is applied to the scan electrode Li is larger than the displacement amount G _{b at} which the amount of reflected or transmitted light of the pixel Aij changes when the basic non-selective voltage waveform B is applied to the pixel Ai.
The displacement amount G _c at which the reflected or transmitted light amount of j changes is larger. Conversely, the non-selected voltage waveforms B and C are determined so that _Gb < _Gc (8).

Further, a comparison between the waveform AF in FIG. 2 (6) and the waveform CF in FIG. 2 (10), or the waveform AE in FIG. 2 (7) and the waveform in FIG. 2 (11). As is clear from the comparison with CE,
The pixel when the selection voltage waveform A is applied to the scan electrode Li is more than the displacement amount G _{c at} which the amount of reflected or transmitted light of the pixel Aij changes when the specific non-selection voltage waveform C is applied to the scan electrode Li.
The displacement amount G _a at which the reflected or transmitted light amount of Aij changes is larger. That is, the relationship of G _b <G _c <G _a (9) holds among G _a , G _b , and G _c .

In the waveform diagram of FIG. 1, the applied voltage V _L1 to the scan electrode _L1
In FIG. 1 (1), the section 0 to t ₁ has the selection voltage waveform A, and the basic non-selection voltage waveform B is repeated over several sections thereafter. Also, the applied voltage V to the scan electrode L2
_L2 (see FIG. 1 (2)) is one section t ₁ away from the scan electrode L1.
The selected voltage waveform A is obtained in the delayed section of t _{1 to} 2t ₁ . That is, the selection voltage waveform A is sequentially applied to the scan electrodes Li according to the line order, and the selection voltage waveform A is applied again to the same scan electrode Li after the period Ta of one frame, that is, the period of 256t ₁ has elapsed. It In addition, after the selection voltage waveform A is applied to each scan electrode Li, eight periods of the interval t1
At Tc, a specific non-selective voltage waveform C is repeatedly applied in addition to the basic non-selective voltage waveform B. As another embodiment of the present invention, the basic non-selective voltage waveform B is not included and the specific non-selective voltage waveform B is not included. Although only the voltage waveform C may be applied, it is preferable to include the basic non-selected voltage waveform B as described later in order to eliminate flicker.

Here, the specific non-selective voltage waveform C is applied also to the subsequent two periods Tc not shown in the section corresponding to the period Tc shown in FIGS. 1 (1) and 1 (2). In general, it does not matter if the specific non-selective voltage waveform C is applied in a plurality of sections before and after the section corresponding to the cycle Tc. That is, all the non-selection voltage waveform application timings before and after the time 0 to t1 in FIG. 1 to which the selection voltage waveform is applied (255 (= 256-1) times in this embodiment)
The specific non-selective voltage waveform C may be applied at a plurality of non-selective voltage waveform application timings less than that. In the period Ta of one frame, only the basic non-selection voltage waveform B is applied in a section other than the section in which the selection voltage waveform A and the specific non-selection voltage waveform C are applied.

In the simple matrix panel used here, ZLI-3488 manufactured by Merck is used as the ferroelectric liquid crystal, and the minimum time of the unit applied voltage waveform required to rewrite the memory state of this ferroelectric liquid crystal material. The width t _m is A- in Fig. 2 (6).
F, the maximum voltage applied by A-E in Fig. 7 (7) is about ± 18V, which is quite slow at 200 to 300 (μsec). On the other hand, in the waveform diagram of FIG. ₁ , six unit time applied voltage waveforms are assigned to one section t ₁ , so one section t _{1 in} this case is t ₁ = 300 (μsec) × 6 = 1.8 (msec)… (10) is set. Therefore, one frame period Ta
Is Ta = 256 × t ₁ = 256 × 1.8 (seconds) ≈ 0.46 (seconds) (11), and the cycle Tc corresponding to the eight intervals t ₁ described above.
Becomes Tc = 8 × t ₁ = 8 × 1.8 = 14.4 (msec) (12). This cycle Tc is smaller than a value 16.6 (msec) obtained by converting the frequency of 60 Hz (passband frequency when human vision is regarded as a low bandpass filter) into a cycle. Conversely,
The cycle Tc in which the application of the specific non-selective voltage waveform C is repeated is set in advance to a value smaller than 16.6 (msec), and a value smaller than 20 (msec) at most in the present invention as described later. ing.

The waveform of the voltage applied to the signal electrode S1 shown in Fig. 1 (3)
In V _S1 , the waveforms of the sections 0 to t ₁ , t _{1 to} 2t ₁ , 4t _{1 to} 5t ₁ , ... Are the dark signal voltage state F shown in FIG.
_The waveforms ₁ to 3t ₁ , 3t _{1 to} 4t ₁ , ... Are bright signal voltage waveforms E shown in FIG. 2 (5). In contrast, in the applied voltage waveform V _S2 to the signal electrode S2 shown in FIG. 1 (4), the interval 0 to t ₁ Conversely,
t _{1 to} 2t ₁ , 4t _{1 to} 5t ₁ , ... are the bright signal voltage waveform E, and the interval 2
t _{1 to} 3t ₁ , 3t _{1 to} 4t ₁ , ... Are dark signal voltage waveforms F.

Accordingly, the waveform of an effective voltage V _L1 -V _S1 applied to the pixel A11 in the interval 0 to t _1, the waveform A-F next to the dark state as shown in FIG. 2 (6), at the same interval 0 to t ₁ pixel The waveform of the effective voltage V _L1 -V _S2 applied to A12 is the waveform AE in the bright state shown in FIG. 2 (7).

As described above, in this driving method, the period Ta of one frame is
During the period, the state in which the basic non-selective voltage waveform B is applied to the scan electrode Li is switched to the state in which the specific non-selective voltage waveform C is applied, and the reflected or transmitted light amount of the pixel Aij on the scan electrode Li is displaced by the displacement amount. Since the change in the amount of light that changes by G _c is repeated many times at a period T _{c of} 16.6 (msec) or less, the state in which the basic non-selection voltage waveform B is applied is switched to the state in which the selection voltage waveform A is applied, and the pixel Aij A part of the change in the amount of light that changes in the amount of reflected or transmitted light in each period Ta by the displacement amount G _a is absorbed in the change in the amount of light that is repeated in the period Tc.

Therefore, the flicker due to the change in the light amount repeated in the cycle Ta is significantly reduced. As mentioned above, centering on the cycle Tc, several sections before and after it
The specific non-selective voltage waveform C can be applied even at t ₁ , but it has been confirmed by the experiments by the present inventors that the flicker that is visually perceptible can be weakened by setting the number of times of application to 3 to 5. It was In addition to such conditions, it was confirmed that flicker can be hardly felt by slightly shifting the polarization axes of the upper and lower polarizing plates of the simple matrix panel from the maximum contrast angle.

In the above embodiment, the case of driving a simple matrix panel having 256 scanning electrodes has been described. However, in general, when a simple matrix panel of M × N using ferroelectric liquid crystal is driven, a specific non-specific Cycle of applying selected voltage waveform C
Tc is determined as follows.

First, a section t required to form each voltage waveform A-F
_When the minimum time width of the unit applied voltage waveform required to rewrite the memory state of the ferroelectric liquid crystal material is t _m , 1 is determined as a value larger than this time width t _m .

Next, by determining an integer H that satisfies the relation of t ₁ × H <16.6 (msec) (13) and minimizes the integer K of K × H ≧ M (14), Tc = T ₁ × H (15), the period Tc is determined. Even if 16.6 (msec) is changed to about 20 (msec) in the equation (13), the effect of reducing flicker can be improved as a result.

Also, a section in which a specific non-selective voltage waveform D different from the specific non-selective voltage waveform C is applied.
It may be applied over several sections before and after t ₁ . However, when the non-selection voltage waveform D is applied to the scan electrode Li, the pixel
Non-selection is performed so that the relationship G _b <G _d <G _a (16) holds between the displacement G _d where the reflected or transmitted light amount of Aij changes and the other displacements G _b and G _a. The voltage waveform D is fixed.

As described above, according to the driving method of the display device of the present invention,
Depending on the specific non-selected voltage waveform applied to the scan electrodes,
The displacement of the reflected or transmitted light amount of the pixel, which is smaller than the displacement of the reflected or transmitted light amount of the pixel in one frame period, which occurs when the state of applying the non-selective voltage waveform to the scan electrode is switched to the state of applying the selective voltage waveform is The flicker caused by the displacement of the reflected or transmitted light amount in one frame period is changed in the period of 20 msec or less during the period of one frame. Therefore, the effect is obtained that the display quality is significantly improved.

[Brief description of drawings]

FIG. 1 is a waveform diagram showing a voltage applied to a display device when a driving method according to an embodiment of the present invention is used, and FIG. 2 is a waveform diagram showing various waveforms of the applied voltage for each unit section. FIG. 3 is a schematic diagram showing an electrode arrangement configuration of a simple matrix panel using a ferroelectric liquid crystal to which the driving method of the embodiment is applied, and FIG. 4 uses a ferroelectric liquid crystal to which a conventional driving method is applied. Sectional view showing a schematic configuration of a simple matrix panel, fifth
FIG. 6 is a plan view showing the electrode arrangement of the simple matrix panel, FIG. 6 is a waveform diagram when the simple matrix panel is driven by a conventional driving method, and FIG. 7 is applied to the pixels of the simple matrix panel. It is a wave form diagram which shows the relationship between an effective voltage and the brightness | luminance of a pixel. L1, L2, ..., Li ... scan electrodes, S1, S2, ..., Sj ... signal electrodes,
A11, A12, ..., Aij ... Pixel, A ... Selection voltage waveform, C ...
Specific non-selected voltage waveform, B ... Basic non-selected voltage waveform,
E …… Bright signal voltage waveform, F …… Dark signal voltage waveform, Tc ……
Application cycle of non-selective voltage waveform C, Ta ... 1 frame cycle

Claims (1)

[Claims] 1. A ferroelectric liquid crystal is interposed between a plurality of scanning electrodes and a plurality of signal electrodes arranged in a direction intersecting with each other, and the ferroelectric liquid crystals at the portions where the scanning electrodes and the signal electrodes intersect each other. As a pixel, a signal voltage waveform corresponding to display data is applied to the signal electrode, while a selection voltage waveform capable of rewriting the display state of the pixel on the electrode is line-sequentially applied to the scanning electrode. Until a selection voltage waveform is applied to the same scan electrode again after a frame, a non-selection voltage waveform whose pixel display state cannot be rewritten is repeatedly applied at the timing when the selection voltage waveform is applied to another scan electrode. In the method for driving a display device as described above, as the non-selection voltage waveform, a basic non-selection voltage waveform and a specific non-selection voltage waveform are applied in a state where the signal voltage waveform is applied to the signal electrode. , When a specific non-selective voltage waveform is applied to the same scan electrode rather than a displacement amount that changes the amount of reflected or transmitted light of pixels on that scan electrode when the basic non-selective voltage waveform is applied to the same scan electrode The displacement amount that changes the amount of light reflected or transmitted by the pixel on the scan electrode is determined to be larger, and the selection voltage waveform is sequentially applied to the other scan electrodes after the selection voltage waveform is applied. During the applied period,
Of multiple non-selective voltage waveform application timings with a period of about 20 ms or less, all non-selective voltage waveform application at a single timing immediately after the selective voltage waveform is applied, or before and after the selective voltage waveform is applied. A method of driving a display device, characterized in that the application is performed at a plurality of non-selection voltage waveform application timings less than the number of timings, while a basic non-selection voltage waveform is applied at other non-selection voltage waveform application timings. .