JPS62289816A - Driving method for optical modulation element - Google Patents

Abstract

PURPOSE:To drive a liquid crystal display panel having a high density picture element extending over a wide area, by forming a potential gradient in at least one conductive film surface for constituting a picture element. CONSTITUTION:A display photoconductive film 2, and parallel electric transmission electrodes 3 of an equal interval are superposed on a glass plate 1, and a picture element A is provided on a crossing part to an opposed photoconductive film 4 on an opposed glass plate. A gap between two substrates is set to about 1mu and a ferroelectric liquid crystal is injected. When electric transmission electrodes 3a, 3c are set to a reference voltage VE=0, and a signal voltage Va is applied to 3b, a gradient Va can be provided in length directions L1, L2 in the film 2 surface. When an inverted threshold value Vth is set to Va, and -Vb is applied to an opposed electrode, Va+Vb exceeding Vth is applied to the liquid crystal corresponding to length directions m1, m2 in the film 2 surface, and an area corresponding to m1 and m2 is converted to dark. Accordingly, when Vb is applied in accordance with a gradation at every picture element, a gradient can be expressed. According to this constitution, a display having a gradient can be executed by driving a liquid crystal panel having a high density picture element extending over a wide area.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method for driving an optical modulation element for a display panel, and more specifically, the present invention relates to a method for driving an optical modulation element for a display panel, and more particularly, the present invention relates to a method for driving an optical modulation element for a display panel. The present invention relates to a display panel using dielectric liquid crystal, particularly a method for driving a liquid crystal optical element suitable for high-density display.

[Prior Art] In a liquid crystal television panel using a conventional active matrix driving method, thin film transistors (TPTs) are arranged in a matrix for each pixel, and a gate-on pulse is applied to the TPTs to bring the source and drain into a conductive state. At this time, a video image signal is applied from the source and stored in the capacitor, and a liquid crystal (for example, twisted nematic: TN-liquid crystal) is driven in response to this stored image signal, and at the same time, the voltage of the video signal is modulated. Gradation display is performed by.

[Problems to be solved by the invention] However, in such active matrix drive type television panels using TN liquid crystals, the TFTs used are
Because TPT has a complicated structure, it requires a large number of structural steps and high manufacturing costs, and it is difficult to spread the thin film semiconductor (e.g. polysilicon, amorphous silicon) that makes up TPT over a large area. There are problems such as difficulty in forming a film over the entire area.

On the other hand, a passive matrix drive type display panel using TN liquid crystal is known as a device that can be manufactured at low manufacturing cost, but in this display panel, as the number of scanning lines (N) increases, one screen (one frame) 1 while scanning
The time during which an effective electric field is applied to one selected point (duty ratio) decreases at a rate of 1/H, which causes crosstalk and has drawbacks such as not providing a high-contrast image. Moreover, when the duty ratio becomes low, it becomes difficult to control the gradation of each pixel by voltage modulation, making it unsuitable for display panels with a high density of wiring, especially liquid crystal television panels.

In view of these problems, an object of the present invention is to provide a method for driving a display panel having high-density pixels over a wide area, and in particular, a method for driving an optical modulation element suitable for high-density display. be.

[Means for Solving the Problems] The present invention provides a plurality of striped conductive films and a first conductive film wired at both ends of the striped conductive films in the longitudinal direction.
a first substrate having a transmission electrode and a second transmission electrode;
a second substrate having a plurality of striped electrodes arranged opposite to the striped conductive film; and an optical modulation material disposed between the first substrate and the second substrate; Driving in which a plurality of levels of scanning signals are sequentially applied to the first electrical transmission electrode, an information signal is applied to the striped electrode in synchronization with the scanning signal, and the second electrical transmission electrode is connected to a reference potential point. method, or in the above method, a plurality of first stripe-shaped conductive films, a first electrical transmission electrode wired at both ends in the longitudinal direction of the conductive films, and a second conductive film.
a first substrate having a transmission electrode, a plurality of second stripe-like conductive films arranged opposite to each other so as to intersect with the first stripe-like conductive film, and wiring at both longitudinal ends of the conductive films. a second substrate having a third transmission electrode and a fourth transmission electrode; and an optical modulation material disposed between the first substrate and the second substrate; Sequentially applying a plurality of levels of scanning signals and connecting the second electrical transmission electrode to a reference potential point; applying a plurality of levels of information signals to the third electrical transmission electrode in synchronization with the scanning signal and the fourth electrical transmission electrode; A driving method in which a transmission electrode is connected to a reference potential point, and the reference potential of the reference potential point is set to 172, which is the threshold potential of the optical modulation material, or in addition to applying,
When connecting the transmission electrodes to the reference potential point, it is preferable to use a driving method in which the transmission electrodes are connected via a resistor having a value approximately equal to the resistance value between the two transmission electrodes.

The optical modulating substance used in the present invention has a first optically stable state (for example, a bright state) and a second optically stable state (for example, a dark state) depending on the applied electric field. ), i.e. has at least two stable states with respect to an electric field, in particular liquid crystals having such properties are 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 these, chiral smectic C phase (Sac''), H phase (SmH phase), and I phase ( S
Suitable is a liquid crystal with one m, F phase (SmF gloss or G phase (Sac)).
URNAL DE PHYSIQUELETTERS”
) Volume 36 (L-69) 1975 “Ferroelectric Liquid Crystals” (rFerro
electric Liquid Cr7stals
J); “Applied Physics Letterspa (
”Applied ph7sics Letters
”) Volume 36, No. 11, 1980 “Submicro Second Bistiple Electro-Optic Switching in Liquid Crystals J.
(r Submicr.

5econd B15table Electroop
tic Switching 1nLiquid Cr
ystalsJ); “Solid State Physics” 1G (141)
1981 "Liquid Crystal", etc., and the ferroelectric liquid crystal disclosed in these documents can be used in the present invention.

More specifically, as an example of the ferroelectric liquid crystal compound used in the method of the present invention, decyloxybenzylidene-P'-amino-2-methylbutylcinnamate (DOBAMBC
), hexyloxybenzylidene-P'-amino-2
-Chloroprovir sinname) ()IOBACPC)
and 4-o-(2-methyl)-butylresolsiliten-4'-octylaniline (MBRA 8).

When constructing an element using these materials, the liquid crystal compound is Sac", S+aH", Sml", SmF",
In order to maintain the temperature in the S layer G, the element can be supported by a copper block or the like in which a heater is embedded, if necessary.

Note that FIG. 16 schematically depicts an example of a ferroelectric liquid crystal cell. 101 and 101' are In2O3, 5n0
It is a substrate (glass plate) coated with a transparent electrode such as 2 or ITO (indium tin oxide), between which a 5raC'' phase liquid crystal with a liquid crystal molecular layer 102 oriented perpendicular to the glass surface is sealed. A thick line 103 represents a liquid crystal molecule, and this liquid crystal molecule 10
3 is a dipole moment in the direction perpendicular to the molecule) (
P) has 104. When a voltage equal to or higher than a certain threshold is applied between the electrodes on the substrates 101 and 101', the helical structure of the liquid crystal molecules 103 is unraveled, and the liquid crystal molecules 103 are twisted so that all dipole moments (CP) 104 are oriented in the direction of the electric field.
The orientation direction can be changed. The liquid crystal molecules 103 have an elongated shape and exhibit refractive index anisotropy in the long axis direction and the short axis direction. Therefore, for example, polarizers can be placed above and below the glass surface in a cross-sectional relationship with each other. For example, it is easily understood that the liquid crystal optical modulation element is a liquid crystal optical modulation element whose optical characteristics change depending on the polarity of applied voltage.

Furthermore, when the thickness of the liquid crystal cell is made sufficiently thin (for example, I
g) As shown in Fig. 17, even when no electric field is applied, the helical structure of the liquid crystal molecules unravels (non-helical structure), and its dipole moment P or P' points upward (11
4) or downward (114').

When an electric field E or E' of different polarity above a certain threshold value is applied to such a cell as shown in FIG. The orientation is changed, and the liquid crystal molecules are accordingly aligned in either the first stable state 113 (bright state) or the second stable state 113' (dark state).

There are two advantages to using such a ferroelectric liquid crystal as an optical modulation element. First, the response speed is extremely fast.
Second, the alignment of liquid crystal molecules has a bistable state. To explain the second point with reference to FIG. 17, for example, when an electric field E is applied, liquid crystal molecules are oriented in a first stable state 113, but this first stable state 113 is maintained even when the electric field is turned off. , and when an electric field E' in the opposite direction is applied, the liquid crystal molecules align to the second stable state 113' and change the orientation of the molecules, but they remain in this state even after the electric field is cut off, and each stable state remains unchanged. It has a memory function. In order to effectively realize such fast response speed and bistability, it is preferable for the cell to be as thin as possible, and generally 0.5 to 20 tiles, especially 1. W ~ 5 le is suitable. A liquid crystal-electro-optical device having a matrix electrode structure using ferroelectric liquid crystals of this kind has been proposed, for example, by Clark and Ragaval in US Pat. No. 4,387,924.

[Function] The present invention includes two substrates having a plurality of conductive films and transmission electrodes, and an optical modulation material disposed between these substrates, and forms a potential gradient within the plane of these conductive films. However, this is a driving method in which scanning signals of multiple levels are applied to the conductive film and the transmission electrode. That is, the present invention applies an in-plane potential gradient to at least one of two conductive films that face each other and constitute one pixel, applies scanning signals of multiple levels, and scans a scanning line area corresponding to each level. It is something that forms. When voltages of multiple levels are applied to the transmission electrodes, the area between the electrodes is divided into multiple areas, and the display density increases accordingly.

[Example] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a perspective view showing one embodiment of an optical modulation element used in the present invention. In FIG. 1, 1 is one substrate, and 2 is a display conductive film laminated on the substrate 1. In FIG. Reference numeral 3 denotes transmission electrodes made of a low-resistance metal film, which are laminated in parallel on the display conductive film 2 at equal intervals. Further, another substrate (not shown) is opposed to the substrate l, and on the other substrate, a counter conductive film (or counter electrode) 4 is disposed to intersect with the transmission electrode 3, and the intersection The optical modulation material is sandwiched between the 0 display conductive film 2 and the counter conductive film 4 in which the pixel region A is formed.

In the liquid crystal optical element configured as described above, the transmission electrode 3
By applying a potential gradient within the surface of the display conductive film 20 by the signal voltage applied to the display conductive film 20, a potential difference gradient is generated in the electric field between the display conductive film 20 and the counter electrode 4. At this time, the transmission electrodes 3a and 3c are connected to the reference potential point VE (for example, O port),
When 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,
In-plane length directions Ll and L2 of the conductive film 2 between 3b and 3c
A potential gradient of Va can be applied to both. At this time, when the inversion threshold voltage vth of the ferroelectric liquid crystal is set as Va and -vb is applied to the counter electrode 4, as shown in FIG. A potential difference Va greater than the inversion threshold voltage vth in the ferroelectric liquid crystal
+Vb is applied, and the area corresponding to the set +12 can be reversed from a bright state to a dark state, for example. Therefore, in the present invention, gradation can be expressed by applying vb to each pixel with a value corresponding to the gradation. At this time, the voltage value of the voltage signal -vb applied to the counter electrode 4 may be modulated according to the gradation information, or the pulse width may be modulated according to the gradation information, or the voltage signal -vb applied to the counter electrode 4 may be modulated in accordance with the gradation information. The gradation can also be controlled by modulating the number of pulses.

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

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

A transparent conductive film of 5i02 film having a thickness of about 200 A was formed on the glass substrate l shown in FIG. 1 by sputtering to form a display conductive film 2. The sheet resistance of this 5i02 film was 106Ω/hole. Next, a 1000A thick film (teAj) was vacuum-deposited on the 5iO2 1112 and patterned again to form a plurality of transmission electrodes 3 as shown in FIG. In this embodiment, the interval between the transmission electrodes 3 is set to 23
It was set as 0 pots. The sheet resistance of this transmission electrode 3 is approximately 0.4Ω
/ mouth, and its width was about 20 feet. On the other hand, an ITO film covering area A was provided as a counter electrode 4 on the counter substrate. The sheet resistance of ITOlfi, which serves as the counter electrode, was approximately 20 Ω/hole.A polyvinyl alcohol layer of approximately 500 A was formed as a liquid crystal alignment film on the surface of each of the two substrates thus created, and then rubbed. Processed.

Next, the two substrates were placed facing each other, the gap was adjusted to about 1μ, 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 where the display conductive film 2 and the counter electrode 4 overlapped was 230 g x 230 p, and the capacitance after the liquid crystal was injected was about 3 PF. However, the width of pixel A is Ll/
2+ L2/2. Then, polarizing plates were arranged in a crossed nicol configuration on both sides of the liquid crystal cell formed in this way, and the optical characteristics were observed.

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

Now, as signal (a) -12V, 200ps
ec pulse, 8 V as signal (b), 200
If an erase step is provided in which the final sec pulse is applied in advance (called an erase pulse), the liquid crystal is switched to the first stable state, and the entire pixel A becomes a bright state (
With the cross polarizing plates arranged like this), from this state,
When various pulses as shown in FIGS. 5(a) to 5(e) are applied as signals (b) to the transmission electrode 3 and applied to the counter electrode 4 in synchronization with the pulse shown in FIG. The optical state is shown in FIG.

Pulse applied voltage -2V (corresponding to Figure 5(a)) and -5■
(corresponding to Fig. 5(b)), no change from the bright state 61 occurs (corresponding to Fig. 6(a)), but when the pulse applied voltage is -8V (corresponding to Fig. 5(C)), no change occurs from the bright state 61. The liquid crystal near the electrode 3 switches to a dark state 62 (corresponding to FIG. 6(b)). Furthermore, when the applied voltage is increased to -14 V (corresponding to FIG. 5(d)), the area of the dark state 62 becomes wider as shown (corresponding to FIG. 6(c)), and the applied voltage is 20 V.
(corresponding to FIG. 5(e)), the entire pixel A is switched to the dark state 62 (corresponding to FIG. 6(d)). In this way, an image with gradation can be formed. .

Furthermore, when signals (b) with different pulse widths as shown in Figures 7(a) to (e) and signals Ca) which are triangular waves as shown in Figure 8 are applied synchronously. However, the optical state change illustrated in FIG. 6 can be shown above. At this time, the pulse shown in FIG. 8 is applied to the transmission electrode, and in synchronization with this pulse, the pulse shown in FIG. 7 (a) to (e) is applied.
) By applying pulses shown in ) to the counter electrode 4 according to the gradation, gradation can be expressed.

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.

Further, as the transmission electrode 3 and counter electrode 4 of the present invention, aluminum (in addition to AI, gold, silver, and copper) can be used.

Metals such as chromium can be used and preferably have a sheet resistance of 102 Ω/hole or less. Furthermore, the conductive film 2 to which a potential gradient is applied has a resistance of 10 to 10 Ω/mouth to 10
A transparent conductive film with a sheet resistance of 9 Ω/hole can be used. Such sheet resistance can be designed to a reasonable value by adjusting the thickness of the transparent conductive film.

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

The display panel shown in FIG. 9 has high resistance striped conductive films 91a, 91b, 91c, . . . on a glass substrate l.
A plurality of striped conductive films 91 are arranged at both ends thereof in the longitudinal direction.
b +92c...and 93a, 93b, 93c・
... is wired.

Opposing electrodes 94a and 94b made of a striped conductive film are arranged on a counter substrate (not shown) facing the substrate 1, and a ferroelectric liquid crystal is arranged between the striped conductive film 91 and the counter electrode 94. Ru.

Now, one of the transmission electrodes 92a, 92b, 92c.
... is connected to the common reference electrode Vs, and the other transmission electrode 9
3a.

A scanning voltage is sequentially applied to 93b, 93c, . However, in the present invention, pixels are formed on the conductive films 91a, 91b, and 91c by patterning the electrodes, and the purpose is to display finer pixels using a driving method, so for example, the conductive film 91a in FIG. There is also a case where display is performed on pixels divided into three, and the display is driven as shown in each of FIGS. 10 to 12.

That is, as shown in FIG. 1O, for example, times tl, t2 . At t3, the peak value is VLI.
.

VL2. A pulse of VL3 is applied to the transmission electrode 93a. At this time, the power transmission electrodes 92 are connected in common, and as shown in FIG. 11, connected to a fixed resistor R3. Here, when a voltage v°C is applied to the transmission electrode 93, the voltage V applied to the transmission electrode 92 becomes Vs = VL-R1/(RL + R5) (R
L is the resistance value between the electrode 82 and the electrode 93). Here, the ninth
The procedure for writing a signal to the pixel A where the conductive film 91a and the counter electrode 94a intersect as shown in the figure is to first apply the voltage VLI to the voltage 93a at the time tl such that VLI = VT with respect to the liquid crystal threshold VT. and resistor R8 to V5
If it is set so that l=VT/2, then R3=RL from the above equation. In this way, VLI"VT is applied to the transmission electrode 93a, and at the same time VA=-V
When r/2 is applied to the counter electrode 94a, the pixel A in FIG.
A voltage exceeding the threshold value VT is applied to the liquid crystal in the entire area corresponding to the pixel A, and the entire area of the pixel A is written in white or black depending on the arrangement of the liquid crystal plate.

Here, the voltage v applied to the transmission electrode 93a is VT
/2<VL<VT, V is applied to the counter electrode 94a.
When A=-VT/2 is applied at the same time, the region L (L is the distance measured from the power transmission electrode 93a) where the voltage Va applied to the liquid crystal satisfies Va>V7 is calculated by the following equation.

VL/2Ll= (VL-VT/2)/L (However,
Ll is the distance ra between the electrodes 92a and 93a), that is, V+
/2< Vt < VT L te, L=L+ (2-
VT/VL). Next, finding the conditions under which a voltage exceeding VT is applied to the liquid crystal in the 273 area of pixel A, VL2 = 3
As shown in FIG. 12, VL2, which is Vr/4, is
Just apply it to a. Also, the condition for applying a voltage exceeding VT to the liquid crystal in 1/3 area of pixel A is VL3 = 3V.
As shown in FIG. 12, VL3 which becomes T15 is
Just apply it to a.

In this way, VLI"VT is sequentially applied to the transmission electrode 93a.

VLz= 3 Vr/4, Vt3= 3 VT1
5, a voltage exceeding VT is sequentially applied to the liquid crystal in the entire area, ⅔ area, and ⅓ area of pixel A. However, the sign of the applied voltage is as shown in FIG. 13. For example, if ±VT/2 is applied alternately to the counter electrode 94a as shown in FIG. 13(a), the area Ll in FIG. Corresponding to the black and white display of L2 and L3, the power transmission electrode 93a has + as shown in FIG. 13(b).
Or a - sign is given. At this time, as is clear from FIG. 13, synchronization is achieved such that the polarity of the voltage applied to the counter electrode 94a is opposite. As a result of the above procedure, as shown in FIG. 13(C), the area Ll.

When white, black, and white are written in L2 and L3, as a result, white, black, and white are written in the areas (R), (G), and (B).

In this way, according to the driving method of the present invention, by applying voltages of multiple levels to the electrodes, it becomes possible to divide the area between the electrodes into multiple areas for display.

Although the example of dividing into three areas has been explained above, it is clear that the display can generally be divided into N areas, and N=
It also shows that when mXn, area gradation display is performed in m stages by dividing into n regions.

In other words, in FIG. 9, the stripe electrode 91
When there are n pixels, the driving method of the present invention, which applies voltage levels of m stages to the electric ai93, can display the number of pixels as mn, or when m = mI x m2, the number of pixels is +HXn. This makes it possible to display m2 levels of gradation.

This is a very important implementation point in that it can reduce the number of connections between panel electrodes and drive elements when performing high-density display such as 4 lines/+n or more or 16 lines/in or more. bring benefits.

Furthermore, it is possible to display high-density and high-quality images even if the number of panel electrodes and drive elements is reduced.
This has the great advantage of significantly reducing display panel manufacturing costs.

For example, in the case of an A4 size display panel, 2
Electrode patterning was performed at 00m+s with 1 line/■, 20
Even if connected with 0 drive elements at 1/m+w, if driven at 4 voltage levels using the driving method of the present invention, it can be displayed as 2 display pixels of 4/] layer, but conventionally In the display panel driving method, 4 electrodes/m+a are patterned, and 200×2=800 driving elements are patterned 4/m+a.
The connection must be made at a density of 1.0 mm, and the reduction in panel manufacturing costs is significant. Further, as shown in FIG. 13(C), for example, Red, G
reen, Bluec7) By arranging three color mosaic filters and applying three voltage levels according to the present invention, three color image displays can be sequentially displayed for one patterning electrode and one driving element. It will be done.

FIG. 14 is a partial circuit diagram showing one embodiment of the driving method according to the present invention, in which electrodes 93a, 93b, and 93c correspond to the electrodes with the same numbers in FIG. In Fig. 14, reference numerals 201a, 201b, and 201c are electrode changeover switches that can select contacts 1, 2, and 3, and each contact is connected to the output of a pulse drive power source 202 through three divided resistors 2.
03.204.205 is the output terminal divided by voltage.

The divided outputs are VLl, VL2 .
VL3, each of the switches 201a, 201
b, 201c, respectively, and by selecting contacts 1, 2.3, VL1. VL2. Apply the potential of VL3. As a result, the electrode 91a shown in FIG.
White or black can be sequentially written in the areas obtained by dividing each of 91b and 91c into three.

At this time, the sheet resistance of the striped electrode 81 is S〒0
When the thickness of the two films is 100A or less, it is 106Ω/ro or less. The resistance value R between the electrodes 92a and 93a in FIG. 9 was approximately 1Ω with a gap of 200μ and an electrode length of 200111111. Therefore, each electrode 92a, 92b, 93c is connected in common, and the bias resistor Rst-1 shown in FIG.
The threshold value V of the liquid crystal, which was selected as Ω, was IOV, the pulse width was 11 seconds, and a pulse voltage of ±VT/2 = ±5 V and pulse width of 1 ms was applied sequentially to the stripe electrodes 94a, 94b, etc. . Here, the transmission electrodes 93a, 93b
, 93c is at the voltage level VLI shown in FIG.

VL2. At VL3, Vz= lh= l0V VL2= 3 VT/4= 7.5 VVL3= 3
A pulse voltage of V115=6 V was applied. The sign of the pulse was carried as shown in FIG. 13, and the pixel was made white or black.

Further, each of the dividing resistors 203, 204, and 205 was set to R(203) = 25Ω, R(204) = 15Ω, and R(205) = 80Ω so as to provide each of the above-mentioned pulse voltages.

As described above, in this example, a liquid crystal display panel having the configuration shown in FIG. 9 was fabricated in A4 size with a stripe electrode density of 4 lines/l, and by using the driving method according to the present invention, one side display density was 3 x 4 = 12 lines. A binary monochrome display panel of /■ was manufactured.

FIG. 15 is a circuit diagram showing another embodiment of the drive circuit according to the present invention, with the same number arrangement as in FIG. 14.
Significant improvements have been made in the following points. That is, the switch groups 201a, 201b, and 201c are simply single-contact switches, and are not multi-contact switches in which each switch corresponds to each resolution point, as in the embodiment of FIG. 14. The multiple contacts in the example of FIG. 14 are consolidated into one switch 20B in the example of FIG. For example, in the example of FIG. 14, the number of contacts is mXn, while in the example of FIG. 15, the number is reduced to m+n.

Regarding the optical modulation element, the most preferable example is a ferroelectric liquid crystal, particularly a ferroelectric liquid crystal having at least two stable states, but the present invention is not limited thereto, and may be applied to other optical modulation elements. It can also be applied to twisted nematic liquid crystals, guest host liquid crystals, etc. as modulation elements.

[Effects of the Invention] As explained above, according to the present invention, a display panel having high density pixels over a wide area can be driven by forming a potential gradient in the plane of at least one conductive film constituting a pixel. A method, particularly a method for driving an optical modulation element suitable for high-density display, can be provided.

[Brief explanation of drawings]

1 and 9 are perspective views of the basic structure of an optical modulation element implementing the driving method of the present invention, FIG. 2 is its potential gradient diagram, FIG. 3 is its basic wiring diagram, and FIG. Figures 5, 7, 8, and 10. Figure 12 and Figure 13 are voltage waveform diagrams, Figure 14 and Figure 1.
5 is a partial circuit diagram, FIG. 6 is a state diagram of a pixel, FIG. 11 is a wiring diagram of a resistor, and FIGS. 18 and 17 are schematic diagrams of a ferroelectric liquid crystal cell. 1; Substrate, 2.92. Conductive fc membrane, 3.93; Electrical transmission electrode, 4.94. Counter electrode. Agent Yutaka 1) To control the Yoshitsukako, figure 1 figure 2 circuit wiring figure 3 wave shape 2 of square (a) figure 4 (Q) -2v t square L (b) Dipping 50 Figure 5 Optical state diagram of pixels Figure 6 Figure 6 IL (b) Forming mouth Figure 7 Figure 7 (1) surface Sugiguchi Figure 8 Amago's 7''4 Visible circle t 1t2 t3 Voltage I-form decoy No. 10 Saito line of Saito line E3 Fig. 11 Fig. 13 Evil circuit entrance Fig. 15 Figure 17

Claims (6)

[Claims] (1) A first substrate having a plurality of striped conductive films and a first power transmission electrode and a second power transmission electrode wired at both ends of the striped conductive films in the longitudinal direction; a second substrate having a plurality of striped electrodes arranged opposite to each other, and an optical modulation material disposed between the first substrate and the second substrate;
Driving in which a plurality of levels of scanning signals are sequentially applied to the first electrical transmission electrode, an information signal is applied to the striped electrode in synchronization with the scanning signal, and the second electrical transmission electrode is connected to a reference potential point. 1. A method for driving an optical modulation element, characterized in that: (2) a first substrate having a plurality of first striped conductive films and a first power transmission electrode and a second power transmission electrode wired at both ends in the longitudinal direction of the conductive films; a second substrate having a plurality of second stripe-shaped conductive films arranged opposite to the conductive film, and a third power transmission electrode and a fourth power transmission electrode wired at both ends of the conductive film in the longitudinal direction; an optical modulation material disposed between the first substrate and the second substrate, and sequentially applies scanning signals of multiple levels to the first transmission electrode, and sets the second transmission electrode to a reference potential. The driving method is characterized in that a plurality of levels of information signals are applied to the third transmission electrode in synchronization with the scanning signal, and the fourth transmission electrode is connected to a reference potential point. A method for driving an optical modulation element according to claim 1. (3) a first substrate having a plurality of striped conductive films and a first power transmission electrode and a second power transmission electrode wired at both longitudinal ends of the striped conductive films; a second substrate having a plurality of striped electrodes arranged opposite to each other, and an optical modulation material disposed between the first substrate and the second substrate;
Driving in which a plurality of levels of scanning signals are sequentially applied to the first electrical transmission electrode, an information signal is applied to the striped electrode in synchronization with the scanning signal, and the second electrical transmission electrode is connected to a reference potential point. A method for driving an optical modulation element, characterized in that the reference potential of the reference potential point is set to 1/2 of the threshold potential of the optical modulation substance. (4) a first substrate having a plurality of first striped conductive films and a first power transmission electrode and a second power transmission electrode wired on both ends of the conductive film in the longitudinal direction; a second substrate having a plurality of second stripe-shaped conductive films arranged opposite to the conductive film, and a third power transmission electrode and a fourth power transmission electrode wired at both ends of the conductive film in the longitudinal direction; an optical modulation material disposed between the first substrate and the second substrate, and sequentially applies scanning signals of multiple levels to the first transmission electrode, and sets the second transmission electrode to a reference potential. In the driving method, the reference potential of the reference potential point is optically connected to a reference potential point, and an information signal is applied to the third electrical transmission electrode in synchronization with the scanning signal, and the fourth electrical transmission electrode is connected to a reference potential point. 2. The method of driving an optical modulation element according to claim 1, wherein the threshold voltage is set to 1/2 of the threshold potential of the modulation substance. (5) a first substrate having a plurality of striped conductive films and a first power transmission electrode and a second power transmission electrode wired at both longitudinal ends of the striped conductive films; a second substrate having a plurality of striped electrodes arranged opposite to each other, and an optical modulation material disposed between the first substrate and the second substrate;
A plurality of levels of scanning signals are sequentially applied to the first electrical transmission electrode, and an information signal is applied to the striped electrode in synchronization with the scanning signal, and the second electrical transmission electrode is connected to the first electrical transmission electrode. Driving the optical modulation element according to claim 1, which is a driving method in which the optical modulation element is connected to a reference potential point via a resistance having a value substantially equal to the resistance value between it and the second transmission electrode. Method. (6) a first substrate having a plurality of first striped conductive films and a first power transmission electrode and a second power transmission electrode wired at both ends in the longitudinal direction of the conductive films; a second substrate having a plurality of second stripe-shaped conductive films arranged opposite to the conductive film, and a third power transmission electrode and a fourth power transmission electrode wired on both ends of the conductive film in the longitudinal direction; an optical modulating material disposed between the first substrate and the second substrate, the scanning signal having a plurality of levels is sequentially applied to the first transmission electrode, and the second transmission electrode Connecting to a reference potential point via a resistance approximately equal to the resistance value between the first and second transmission electrodes, and applying an information signal to the third transmission electrode in synchronization with the scanning signal. Further, the driving method is characterized in that the fourth transmission electrode is connected to a reference potential point via a resistance having a value approximately equal to the resistance value between the third transmission electrode and the fourth transmission electrode. A method for driving an optical modulation element according to claim 1.