JPH07119907B2 - Driving method of optical modulator - Google Patents

Description

The present invention relates to a method of driving an optical modulator for a display panel, and more particularly to a display using a liquid crystal material having bistability, particularly a ferroelectric liquid crystal. The present invention relates to a driving method of a liquid crystal optical element suitable for a panel, particularly a high-density display.

[Prior Art] In a liquid crystal television panel using a conventional active matrix drive system, thin film transistors (TFTs) are arranged in a matrix for each pixel, and a gate-on panel is applied to the TFT to make a source and a drain conductive. At this time, the video image signal is applied from the source and stored in the capacitor, and the liquid crystal (for example, twisted nematic; TN-liquid crystal) is driven corresponding to the stored image signal, and at the same time, the voltage of the video signal is modulated. Is used for gradation display.

[Problems to be Solved by the Invention] However, in an active matrix drive type television panel using such a TN liquid crystal, since the TFT used has a complicated structure, the number of structural steps is large, High manufacturing cost is a bottleneck, and it is difficult to form a thin film semiconductor (for example, polysilicon or amorphous silicon) forming a TFT over a wide area.

On the other hand, a passive matrix drive type display panel using TN liquid crystal is known as one that can be manufactured at a low manufacturing cost. In this display panel, one screen (one frame) is displayed as the scanning line (N) increases. The time (duty ratio) in which an effective electric field is applied to one selected point during scanning decreases at a rate of 1 / N, which causes crosstalk and does not result in a high-contrast image. In addition, since it becomes difficult to control the gradation of each pixel by voltage modulation when the duty ratio is low, it is not suitable for a display panel having a high density of wirings, particularly a liquid crystal television panel.

In view of such problems, an object of the present invention is to provide a driving method of a display panel having high-density pixels over a large area, and in particular, a driving method of an optical modulator suitable for high-density display. is there.

[Means for Solving Problems] In the present invention, a plurality of pixels in which an optical modulation substance is arranged between a pair of conductive films facing each other are arranged in a matrix and scanning is performed by commonly connecting the plurality of pixels for each row. An optical modulation element including an electrode group and an information electrode group in which a plurality of pixels are commonly connected in each column, and each of the scanning electrodes includes the conductive film and two transmission lines having a resistance lower than that of the conductive film. Is a driving method of an optical modulation element for driving so that a potential difference gradient is generated between the pair of conductive films forming the pixel by applying different voltages to the two transmission lines. Forming a first potential gradient in the conductive film between the two and applying a first information signal to the information electrode group to determine the optical state of the entire area in the pixel; and between the two transmission lines. The conductive film of the first Forming a second potential gradient having the same direction as that of the potential gradient and having a different potential level, and applying a second information signal to the information electrode group to change the optical state of a specific region in the pixel. And a driving method of the optical modulation element.

The optical modulator used in the present invention includes a first optically stable state (for example, a bright state) and a second optically stable state (for example, a dark state) depending on an applied electric field. A substance having at least two stable states against an electric field, in particular a liquid crystal having such a property is used.

As a liquid crystal having bistability that can be used in the driving method of the present invention, a chiral smectic liquid crystal having ferroelectricity is most preferable, and among them, a chiral smectic C phase (SmC ^* ), H phase (SmH ^* ), I phase. (SmI ^* ), F
Phase (SmF ^* ) and G phase (SmG ^* ) liquid crystals are suitable. About this ferroelectric liquid crystal, "LE JOURNAL DE PHYSIQUE LET"
TERS ") Volume 36 (L-69) 1975" Ferroelectric Liquid Crystals "(" Ferroelectric Li
quid Crystals ”);“ Applied Physics
Letters "(" Applied physics Letters ") Volume 36, Vol.
No. 11, 1980 "Submicro Second Bistable Electro-Optic Switching In Liquid Crystals"("Submicro Second Bistable
Electrooptic Switching in Liquid Crystals ");
“Solid state physics” 16 (141) 1981 “Liquid crystal” and the like, and the ferroelectric liquid crystal disclosed therein can be used in the present invention.

More specifically, examples of the ferroelectric liquid crystal compound used in the method of the present invention include desiloxybenzylidene-p'-amino-2-methylbutylcinnamate (DOBAMBC) and hexyloxybenzylidene-p'-amino-. 2-chloropropyl cinnamate (HOBACPC) and 4-o- (2
-Methyl) -butyl resorcylidene-4'-octylaniline (MBRA 8) and the like.

When an element is constructed using these materials, a heater is used for the element as necessary to maintain the liquid phase compound in a temperature state where SmC ^* , SmH ^* , SmI ^* , SmF ^* , and SmG ^*. It can be supported by an embedded copper block or the like.

FIG. 16 is a diagram for schematically illustrating an example of a ferroelectric liquid crystal cell. 101 and 101 ′ are substrates (glass plates) coated with transparent electrodes such as In ₂ O ₃ , SnO ₂ and ITO (Indium-Tin-Oxide), between which the liquid phase molecular layer 102 is perpendicular to the glass surface. A liquid crystal of SmC ^* phase oriented so that A thick line 103 represents a liquid crystal molecule, and the liquid crystal molecule 103 has a dipole moment (P _⊥ ) 104 in a direction orthogonal to the molecule. Board 101 and
When a voltage higher than a certain threshold is applied between the electrodes on 101 ', the helical structure of the liquid crystal molecules 103 is unwound, and the orientation direction of the liquid crystal molecules 103 is changed so that all the dipole moments (P _⊥ ) 104 are oriented in the electric field direction. be able to. The liquid crystal molecule 103 has an elongated shape, and exhibits refractive index anisotropy in the major axis direction and the minor axis direction thereof. Therefore, for example, polarizers arranged in a crossed Nicol positional relationship above and below a glass surface should be placed. For example, it is easy to understand that the liquid crystal optical modulation element has optical characteristics that change depending on the polarity of voltage application. If the liquid crystal cell is made sufficiently thin (for example, 1 μm),
As shown in FIG. 17, even when no electric field is applied, the helical structure of the liquid crystal molecule is unwound (non-helical structure), and its dipole moment P or P ′ is upward (114) or downward (1
Take one of 14 '). No. 17 in such a cell
As shown in the figure, when electric fields E or E'having different polarities equal to or higher than a certain threshold value are applied, the electric field E or E'is changed in the upward direction 114 or the downward direction 114 'according to the electric field vector of the dipole moment electric field E or E'. Liquid crystal molecules are in the first stable state 113
(Bright state) or second stable state 113 '(dark state)
Orient one of them.

There are two advantages of using such a ferroelectric liquid crystal as an optical modulation element. First, the response speed is extremely fast,
Secondly, the orientation of liquid crystal molecules has a bistable state. Explaining the second point with reference to FIG. 17, for example, when an electric field E is applied, the liquid crystal molecules are aligned in the first stable state 113. In this state, even if the electric field is cut off, the first stable state 11 is generated.
When 3 is maintained, and when an electric field E'in the opposite direction is applied, the liquid crystal molecules are oriented in the second stable state 113 'and change their orientation.
It has a memory function in each stable state. In order to effectively realize such a high response speed and bistability, it is preferable that the cell is as thin as possible, and generally 0.5 μ to 20 μ, particularly 1 μ to 5 μ is suitable.
A liquid crystal-electro-optical device having a matrix electrode structure using a ferroelectric liquid crystal of this kind has been proposed by Clarke and Lagabal in US Pat. No. 4,367,924.

[Operation] In the present invention, by forming a first potential gradient in the conductive film between the two transmission lines and applying a first information signal to the information electrode group, the entire area in the pixel is covered. After the optical state is set to either the bright state or the dark state, a second potential gradient having the same direction as the first potential gradient and a different potential level is applied to the conductive film between the two transmission lines. Is formed and a second information signal is applied to the information electrode group to determine the optical state of a specific area in the pixel which is previously set in the same state, so that one pixel is divided into a plurality of areas. Then, the display density becomes higher by that amount.

EXAMPLES Examples of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a perspective view showing an embodiment of an optical modulator used in the present invention. In FIG. 1, reference numeral 1 is one substrate and 2 is a display conductive film laminated on the substrate 1. Reference numeral 3 denotes a transmission electrode made of a low resistance metal film, which is laminated on the display conductive film 2 in parallel at equal intervals. Further, the other substrate (not shown) is opposed to the substrate 1, and the counter conductive film (or counter electrode) 4 is arranged on the other substrate so as to intersect with the transmission electrode 3 and the intersection thereof. A pixel area A is formed in the portion. The optical modulator is sandwiched between the display conductive film 2 and the counter conductive film 4.

In the liquid crystal optical element configured as described above, the transmission electrode 3
By applying a potential gradient within the surface of the conductive film for display 2 by the signal voltage applied to, a potential difference gradient is generated in the electric field between the counter electrode 4. At this time, the transmission electrode 3a and
When 3c is connected to the reference potential point VE (for example, 0 volt) and a predetermined signal voltage Va is applied to another transmission electrode 3b, as shown in FIG. 2 (a), between the transmission electrodes 3a and 3b, 3b and A potential gradient of Va can be applied to the in-plane length direction L ₁ and L ₂ of the conductive film 2 between 3c. The inversion threshold voltage Vth of this time ferroelectric liquid crystal as Va, is applied to -Vb to the counter electrode 4, the longitudinal direction m ₁ in the plane of the conductive film 2 as shown in FIG. 2 (b), m ₂ inversion threshold voltage Vth or higher potential difference Va + Vb to the ferroelectric liquid crystal corresponding is to be applied to, such m _1, m ₂
The region corresponding to can be inverted from the bright state to the dark state, for example. Therefore, in the present invention, the gradation can be expressed by applying Vb with a value according to the gradation for each pixel. At this time, the voltage signal −Vb applied to the counter electrode 4
May be modulated in its voltage value according to gradation information, or its pulse width may be modulated in accordance with gradation information,
Alternatively, the gradation can be controlled by modulating the number of pulses.

Further, in the present invention, prior to applying the gradation signal,
After passing through an erasing step to put the pixel into either a bright state or a dark state, an inversion voltage for inverting the state is controlled according to the gradation and applied to the ferroelectric liquid crystal. It is necessary.

Furthermore, preferred specific examples of the present invention will be described.

A transparent conductive film of a SiO ₂ film having a thickness of about 200 Å was formed on the glass substrate 1 in FIG. 1 by a sputtering method to form a display conductive film 2. The sheet resistance of this SiO ₂ film is
It was 10 ⁶ Ω / mouth. Next, Al is vacuum-deposited on the SiO ₂ film to a thickness of 1000Å and patterned again to form a first
As shown in the figure, a plurality of transfer electrodes 3 were formed. In this embodiment,
The distance between the transmission electrodes 3 was 230 μm. The sheet resistance of this transmission electrode 3 is about 0.4 Ω / port, and its width is about 20 μ. On the other hand, the counter substrate is covered with ITO that covers the area A.
The film was provided as the counter electrode 4. This counter electrode ITO
The sheet resistance of the membrane was about 20 Ω / mouth.

A polyvinyl alcohol layer having a thickness of about 500 Å was formed as a liquid crystal alignment film on each surface of the two substrates thus prepared, and subjected to rubbing treatment.

Next, the two substrates are opposed to each other and adjusted so that the gap becomes about 1 μ, and the ferroelectric liquid crystal (p-η-octyloxybenzoic acid-p ′-(2-methylbutyloxy) phenyl ester and p- A liquid crystal composition containing η-nonyloxybenzoic acid-p ′-(2-methylbutyloxy) phenyl ester as a main component was injected. The shape of the partial pixel A in which the display conductive film 2 and the counter electrode 4 overlap was 230 μ × 230 μ, and the electrostatic capacity after liquid crystal injection was about 3 PF. However, the width of the pixel A was _{L 1/2 + L 2/} 2. Then, on both sides of the liquid crystal cell thus formed. The polarizing plate was arranged in crossed Nicols and the optical characteristics were observed.

FIG. 3 is a schematic diagram showing a method of applying an electric signal,
The display conductive film 2 is formed on the substrate 1, and the transmission electrode 3 is further arranged thereon, and the counter conductive film 32 is formed on the counter substrate 31.
And the ferroelectric liquid crystal 33 is sandwiched between the two substrates. The counter conductive film 32 is connected to the first drive circuit 34, and the display conductive film 2 is connected to the second drive circuit 35. FIG. 4 shows the waveform of the signal (a) generated by the drive circuit 34 of FIG. 3, and FIG. 5 shows the waveform of the signal (b) generated by the drive circuit 35 of FIG.

Now, by providing an erasing step that gives a -12 V, 200 μsec pulse as the signal (a) and an 8 V, 200 μsec pulse as the signal (b) in advance (referred to as an erasing pulse), the liquid crystal is brought into the first stable state. As a result of switching, the entire pixel A is in a bright state (the cross polarizing plate is arranged in this way). From this state, when various pulses as shown in FIGS. 5 (a) to 5 (e) are given to the counter electrode 4 in synchronization with the pulse of FIG. 4 applied to the transmission electrode 3 as the signal (b). FIG. 6 shows the optical state of the pixel A of FIG.

There is no change from the bright state 61 (corresponding to FIG. 6 (a)) at the pulse applied voltage −2V (corresponding to FIG. 5 (a)) and −5V (corresponding to FIG. 5 (b)). , Pulse applied voltage −8V
In (corresponding to FIG. 5 (c)), the liquid crystal in the vicinity of the transmission electrode 3 switches to the dark state 62 (corresponding to FIG. 6 (b)).
Further, when the applied voltage is increased to −14 V (corresponding to FIG. 5 (d)), the region of the dark state 62 becomes wide as shown (corresponding to FIG. 6 (c)), and the applied voltage 20 V (corresponding to FIG. 6 (c)). Fig. 5 (e)
Then, the whole pixel A is switched to the dark state 62 (corresponding to FIG. 6 (d)). In this way, an image with gradation can be formed.

Further, various signals (b) having different pulse widths as shown in FIGS. 7 (a) to (e) and a triangular signal (a) as shown in FIG. 8 were given in synchronization. At any time, the optical state change illustrated in FIG. 6 can be shown above. At this time, the panel shown in FIG. 8 is applied to the transmission electrode and applied to the counter electrode 4 in synchronization with this pulse in accordance with the pulse gradation shown in FIGS. Can express sex.

The liquid crystal 33 of this embodiment shown in FIG. 3 is a ferroelectric liquid crystal, more preferably a chiral smectic liquid crystal in a bistable state.

In addition to aluminum (Al), metals such as gold, silver, copper and chromium can be used for the transmission electrode 3 and the counter electrode 4 of the present invention, and the sheet resistance thereof is preferably 10 or less.
² Ω / □ or less. Furthermore, as the conductive film 2 to which a potential gradient is applied, a transparent conductive film having a sheet resistance of 10 KΩ / port to 10 ⁹ Ω / port can be used. Such sheet resistance can be designed to an appropriate value by adjusting the film thickness of the transparent conductive film.

FIG. 9 is a perspective view showing a specific example in which the gradation surface according to the present invention is applied to matrix driving.

In the display panel shown in FIG. 9, a plurality of high-resistance striped conductive films 91a, 91b, 91c ... Are arranged on the glass substrate 1, and low-strength electrical transmission is provided at both longitudinal ends of each striped conductive film 91. The electrodes 92a, 92b, 92c ... And 93a, 93b, 93c ... Are wired. Counter electrodes 94a and 94b made of a stripe-shaped conductive film are arranged on a counter substrate (not shown) facing the substrate 1, and a ferroelectric liquid crystal is arranged between the stripe-shaped conductive film 91 and the counter electrode 94. It

Now, one of the transfer electrodes 92a, 92b, 92c ...
, and the scanning voltage is sequentially applied to the other transmission electrodes 93a, 93b, 93c .... However, according to the present invention, the pixel formed by patterning the electrodes is formed on the conductive films 91a, 91b, 91c, and the pixel is displayed on a finer pixel by the driving method. Therefore, for example, the conductive film 91a shown in FIG. In some cases, the image is displayed on pixels divided into three, and the pixel is driven as shown in each of FIGS. 10 to 12.

That is, as shown in FIG. 10, for example, time t _{1 at 1} ms intervals,
At t ₂ and t ₃ , pulses having peak values V _L1 , V _L2 , and V _L3 are applied to the transmission electrode 93a. At this time, the transmission electrodes 92 are commonly connected and are connected to the fixed resistance R _{S as} shown in FIG.
When the voltage V _L is applied to the transfer electrode 93, the voltage V _S applied to the transfer electrode 92 becomes V _S = V _L R _S / (R _L + R _S ) (R _L is the electrode 92 and the electrode Resistance value between 93). here,
Procedure for writing a signal to the pixel A at the intersection of the conductive film 91a and the counter electrode 94a shown in FIG. 9, the voltage V _L1 First, the time t _1
So that V _L1 = V _T with respect to the liquid crystal threshold V _T ,
When the resistance R _{S is set} to V _S1 = V _T / 2 by applying it to the transmission electrode 93a, R _S = R _L from the above formula. In this way, V _L1 = V _T is applied to the transmission electrode 93a, and at the same time V _A
= −V _T / 2 is applied to the counter electrode 94a, the pixel A of FIG.
A voltage exceeding the threshold value V _T is applied to the liquid crystal in the entire area corresponding to, and the entire area of the pixel A is written in white or black corresponding to the arrangement of the liquid crystal plate.

Here, the voltage V _L applied to the transmission electrode 93a is set to V _T / 2 <V _L <V
_{When T} is _T , a region L in which the voltage Va applied to the liquid crystal is Va> V _T when V _A = −V _T / 2 is simultaneously applied to the counter electrode 94a.
(L is the distance measured from the transmission electrode 93a) is calculated by the following equation.

V _L / 2L ₁ = (V _L −V _T / 2) / L (where L ₁ is the distance between the electrodes 92a and 93a) That is, V _T / 2 <V _L <V _T , and L = L ₁ ( 2-V _T / V _L ). Next, the condition for applying a voltage exceeding V _T to the liquid crystal in the 2/3 area of the pixel A is obtained. As shown in FIG. 12, V _L2 is V _L2 = 3V _T / 4. Can be applied to. Further, the condition a voltage exceeding the liquid crystal V _T 1/3 region of the pixel A is applied, the V _L3 = 3V _T / 5 to become V _L3, as shown in FIG. 12, applied to the electrical transmission electrode 93a do it.

In this manner, V _L1 = V _T , V _L2 = 3V _T / 4,
By applying V _L3 = 3V _T / 5, the whole area of pixel A, 2
A voltage exceeding V _T is sequentially applied to the liquid crystal in the / 3 region and the 1/3 region. However, the sign of the applied voltage is as shown in FIG. 13. For example, when ± V _T / 2 is alternately applied to the counter electrode 94a as shown in FIG. 13 (a), the region L in FIG. ₁ , L ₂ , L ₃
Corresponding to black and white display, + or-is given to the transmission electrode 93a as shown in FIG. 13 (b). still,
At this time, as is clear from FIG. 13, synchronization is established such that the polarity is opposite to the voltage applied to the counter electrode 94a. As a result of the above procedure, as shown in FIG. 13C, when white, black, and white are written in the regions L ₁ , L ₂ , and L ₃ , the results (R), (G), ( White, black, and white are written in the area B).

As described above, according to the driving method of the present invention, it is possible to divide the region between the electrodes into a plurality of regions for display by applying voltages of a plurality of levels to the electrodes.

Although the example of three divisions has been described above, it is clear that the display can be generally divided into N areas and N =
When m × n, it is also shown that there are m stages of area gradation display divided into n regions.

In other words, when there are n stripe electrodes 91 in FIG. 9, the driving method of the present invention in which m voltage levels are applied to the electrodes 93 can be displayed as mn pixels, or m = When m ₁ × m ₂ is set, the number of pixels of m ₁ × n
m ₂ gradation display is possible.

This is a great mounting advantage in that the number of connections between the panel electrodes and the driving elements can be reduced when high-density display of 4 lines / mn or more or 16 lines / mn or more is performed. Bring In addition, even if the number of electrodes on the panel and the number of driving elements themselves are reduced, high-density and high-quality display is possible, which is a great advantage that the manufacturing cost of the display panel is significantly reduced.

For example, in the case of A4 size display panel, 200m in the width direction
Even if electrode patterning is performed at a rate of 1 line / mm and 200 drive elements are connected at a rate of 1 line / mm, for example, if the drive method of the present invention drives at four voltage levels, 4 lines / mm It can be displayed as the number of binary display pixels, but in the conventional display panel driving method, patterning of 4 electrodes / mm of electrode, 200 × 2 = 80
Since 0 driving elements must be connected at a density of 4 / mm, the panel manufacturing cost is greatly reduced. In addition, for example, as shown in FIG. 13 (c), a color mosaic filter of three colors of Red, Green, and Blue is arranged in one patterning electrode to apply three voltage levels according to the present invention. For example, color image display of three colors is sequentially performed for one patterning electrode and one driving element.

FIG. 14 is a partial circuit diagram showing one embodiment of the driving method according to the present invention. The electrodes 93a, 93b, 93c correspond to the electrodes with the same numbers in FIG. In FIG. 14, 201a, 201b, and 201c are electrode changeover switches, and contacts 1, 2 and 3 can be selected. At each contact, the output of the pulse drive power source 202 is divided by three dividing resistors 203, 204 and 205. It is an output terminal. This divided output corresponds to V _L1 , V _L2 , and V _L3 in FIG. 12, and the switches 201a, 201b, and 201c are sequentially connected to the contacts 1, 2, and
By selecting ₃ , the potentials of V _L1 , V _L2 , and V _L3 are sequentially applied. As a result, white or black can be sequentially written in the regions shown in FIG. 9 in which the electrodes 91a, 91b, 91c are each divided into three.

At this time, the sheet resistance of the stripe electrode 91 is 10 ⁶ Ω / port or less when the thickness of the SnO ₂ film is 100 Å or less. The resistance value R _L between the electrodes 92a and 93a in FIG. 9 has a gap of 200 μ and an electrode length of 2
At 00 mm, it was about 1 kΩ. Therefore, each electrode 92a, 92b, 92c
, And the bias resistor R _S shown in FIG. 11 was selected to be 1 kΩ. The liquid crystal threshold V _T is 10 V, the pulse width is 1 ms, and ± V _T / 2 = ± 5 V, pulse width is sequentially applied to the stripe electrodes 94a, 94b.
A pulse voltage of 1 ms was applied. Here, the transmission electrodes 93a, 93b, 9
The voltage applied to 3c is the voltage level V shown in FIG.
In _L1, V _L2, V _L3, was applied a pulse voltage of _{V L1 = V T = 10V V} L2 = 3V T /4=7.5VV L3 = 3V T / 5 = 6V. The sign of the pulse was carried as shown in FIG. 13, and the pixel was white or black. Also, each division resistor
203, 204 and 205 were set to R (203) = 25Ω R (204) = 15Ω R (205) = 60Ω so as to give the above pulse voltages.

As described above, in this embodiment, the liquid crystal display panel having the structure shown in FIG. 9 was formed in A4 size with the stripe electrode density of 4 lines / mm, and the one side display density of 3 was obtained by the driving method according to the present invention.
We produced a binary monochrome display panel with × 4 = 12 lines / mm.

FIG. 15 is a circuit diagram showing another embodiment of the drive circuit according to the present invention, which has the same numbering arrangement as that of FIG. 14, but is greatly improved in the following points. That is, the switch groups 201a, 201b, 201c are mere one-contact switches, and are not multi-contact switches in which each switch corresponds to each resolution point as in the embodiment of FIG. The multi-contact portion of the example of FIG. 14 is integrated into one switch 206 in the example of FIG. 15, and as a result, when comparing the number of contacts, one electrode is resolved into n with m electrodes. If so, in the example of FIG. 14, the number of contacts is mx
While the number is n, in the example of FIG. 15, it is drastically reduced to m + n.

Regarding the optical modulation element, the case where the ferroelectric liquid crystal, and sometimes the ferroelectric liquid crystal having at least two stable states, has been described as the most preferable example, but the present invention is not limited thereto and other optical elements are used. It can be applied to twist nematic liquid crystal, guest-host liquid crystal, etc. as a modulator.

[Effects of the Invention] As described above, according to the present invention, a display panel having high-density pixels over a wide area is formed by forming a potential gradient in at least one conductive film surface forming a pixel. It is possible to provide a method, in particular, a method for driving an optical modulator suitable for high-density display.

[Brief description of drawings]

1 and 9 are perspective views of the basic structure of an optical modulator for implementing the driving method of the present invention, FIG. 2 is its potential gradient diagram, FIG. 3 is its basic wiring diagram, and FIG. Figure 5, Figure 5, Figure 7, Figure 8, Figure 10, Figure 12, and Figure 13 are voltage waveform diagrams, Figures 14 and 15 are partial circuit diagrams, and Figure 6 is a pixel state diagram. FIG. 11 is a resistance wiring diagram, and FIGS. 16 and 17 are schematic diagrams of a ferroelectric liquid crystal cell. 1; substrate, 2,92; conductive film, 3,93; transfer electrode, 4,94; counter electrode.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hisashi Shindo 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) References JP 61-201217 (JP, A) JP 52 -20851 (JP, A) JP-A-52-122098 (JP, A)

Claims (2)

[Claims] 1. A scanning electrode group in which a plurality of pixels in which an optical modulation substance is arranged between a pair of conductive films facing each other are arranged in a matrix, and a plurality of pixels are commonly connected in each row, and a plurality of pixels in each column. A group of information electrodes to which pixels are connected in common, wherein the scanning electrodes have an optical modulation element having the conductive film and two transmission lines each having a resistance lower than that of the conductive film, A driving method of an optical modulation element for driving so that a potential difference gradient is generated between the pair of conductive films forming the pixel by applying different voltages, wherein the first conductive film is formed on the conductive film between the two transmission lines. Forming a potential gradient and applying a first information signal to the information electrode group to determine the optical state of the entire area in the pixel; and the first conductive film between the two transfer lines. Gradient in the same direction as the potential gradient And forming a second potential gradient having a different potential level and applying a second information signal to the information electrode group to determine an optical state of a specific region in the pixel. And a method for driving an optical modulator. 2. The method for driving an optical modulation element according to claim 1, wherein the optical modulation substance is a ferroelectric liquid crystal.