JP2753928B2 - Liquid crystal display - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display using a liquid crystal having a memory property, and more particularly to a liquid crystal display having a frame around a display.

[0002]

2. Description of the Related Art In an electro-optical medium having a memory property, a desired switching is performed by applying an electric field higher than a threshold value. State is maintained. A medium having such characteristics has a memory effect, and once the desired switching is performed by a write signal, the information is stored. Therefore, the medium can be applied to a large-capacity display element or the like.

A typical example of an electro-optical medium having such a memory property is a ferroelectric liquid crystal. A ferroelectric liquid crystal (FLC) is sandwiched between substrates having appropriate alignment treatment,
By creating a cell in which the liquid crystal is thin enough to eliminate the helical structure, two stable states having memory properties are developed.

Such a liquid crystal cell uses at least one polarizer and can distinguish the above two stable states into a dark state and a bright state by using birefringence of liquid crystal.
The switching between the two states is controlled by an electric signal applied through an electrode formed by performing desired patterning on the substrate.

In such a liquid crystal cell, generally, a scanning electrode group in the form of stripes is formed on one substrate and a group of information electrodes in the form of stripes is formed on the other substrate, and the liquid crystal cell is applied to these electrode groups. By combination of the scanning signal and the information signal, a bright state and a dark state are written to the pixel formed at the intersection of each electrode group, and are used as a display element.

[0006]

When an electro-optical medium having a memory property such as FLC is used as a display element, there are the following problems.

That is, the display element is housed in a chassis or a decorative box in order to maintain functionality, safety and aesthetics, and to protect the element electrical system. The surface may be hidden when viewed from an oblique direction. In order to avoid such a case, a frame portion (non-display portion) is provided around the display portion, and as long as the effective display area is viewed from an angle other than a certain range,
The device has been devised so that it is not hidden.

However, in this case, if the frame is a medium having a memory property such as FLC, the FLC is in an arbitrary state until an electric signal of a threshold value or more is applied. Becomes uncontrollable, and the display becomes uneven, which is unsightly in practical use and impairs aesthetic appearance. Therefore, it is necessary to make the frame part uniform by a certain electric signal. However, the memory property here is not limited as long as it satisfies image quality and display function as a display element. Therefore, it is necessary to apply the drive signal periodically.

Therefore, a frame driving electrode is provided around the display section, and an electric signal similar to that of the display section or substantially the same as that of the display section is applied to the electrodes to drive the liquid crystal in the frame section so that a uniform frame section is formed. Has been conventionally proposed (for example, Japanese Patent Publication No. 2-30022, Japanese Patent Publication No. 4-23275).

However, in the liquid crystal element having such a frame portion, the cell thickness is likely to be increased in the vicinity of the sealing material, the alignment state is likely to be rough in the vicinity of the liquid crystal injection port, and in the vicinity of the waveform applying circuit. The threshold value of the frame portion is liable to vary greatly due to the temperature fluctuation and the like, and stable display cannot be performed in the frame portion.

Further, when the conventional cell structure is used, there are the following problems in the durability of the liquid crystal cell. That is, it is known that the ferroelectric liquid crystal molecules move to some extent by a non-selection signal during matrix driving. This is apparent from the fact that when the optical response of the pixel to which the non-selection signal is applied is taken, the light amount fluctuates in synchronization with the applied pulse. In the so-called splay orientation (orientation in which the angle of the long axis of the molecule is greatly twisted between the upper and lower substrates), such fluctuation of the molecule retains the displayed content unless the stable position of the molecule is changed (switched) by the change. Since it was possible, there was no problem except for a slight decrease in contrast. However, in a cell having an orientation in which the change in the angle of the molecular major axis between the upper and lower substrates is relatively small (hereinafter referred to as a uniform orientation), a phenomenon in which liquid crystal molecules move in a layer by applying a voltage (for example, a non-selection signal). Can be seen. This phenomenon will be described in detail with reference to FIG.

FIG. 15A shows a cell state before voltage application, and FIG. 15B shows a cell state after voltage application. The ferroelectric liquid crystal 801 is sealed in a seal member 802. The alignment layer is made of a polyimide thin film, and the rubbing direction is performed in both (a) and (b) from bottom to top in parallel with the upper and lower substrates. By performing such processing, FIG.
As shown in (c), the smectic layer is generated in a direction perpendicular to the rubbing direction.

When the cell thickness is made thin enough to cancel the helical pitch, the ferroelectric liquid crystal molecules can take two stable states, but one of the two states changes the direction of all the molecules in the cell. Keep them aligned. If this state is a state of + θ (FIG. 15D), another stable state exists at a position of −θ almost symmetrically with respect to the layer normal vector i.

When an electric field (for example, a rectangular wave of 10 Hz, ± 8 V) is applied to the entire surface of the cell under the state of + θ, the liquid crystal molecules maintain the inclination with respect to the layer normal of + θ, and FIG.
It starts to move in the layer in the direction from the point A in the middle to the point B. As a result, when voltage application is continued for a long time, a portion E without liquid crystal is generated at the A end as shown in FIG. 15B, and the cell thickness of the B portion is larger than that of the A portion. When the liquid crystal molecules are in the state of -θ, the liquid crystal moves in the layer from the B end to the A end, and a void portion such as an E portion where no liquid crystal exists is generated at the B end.

[0015] Such a phenomenon can take from 1000 hours to 2000 hours.
It occurs in a relatively short period of time. The presence of a part which cannot be controlled electro-optically, such as the part E, is not desirable in terms of display quality, and the drive control of the entire liquid crystal panel is difficult if the cell thicknesses of the parts A and B change with time. This has been a major problem as an optical element using a ferroelectric liquid crystal.

In particular, in the case of a display element having a frame portion around the display portion, the above-mentioned void portion and a portion having a large cell thickness tend to occur in the frame portion. The occurrence of voids and changes in cell thickness in such a frame portion cause the threshold value of the frame portion to vary greatly, as in the case where the above-described variation in cell thickness and roughening of the alignment state and temperature fluctuation have occurred. In some cases, stable display could not be performed in the frame portion, and the frame could not function sufficiently as a display device.

An object of the present invention is to enhance the function as a display device in view of the above-mentioned drawbacks of the prior art.

[0018]

In order to solve the above-mentioned problems, according to the present invention, a smectic layer structure is provided between an electrode substrate having a scanning electrode group and an electrode substrate having an information electrode group.
A display section for displaying a first stable state and a second stable state is formed by arranging liquid crystal having a memory property, and a frame scanning electrode and a frame information electrode are arranged outside the scanning electrode group and the information electrode group. In a matrix type liquid crystal display device which forms a frame part,
For one of the two stable states, 2
Compared to the waveform applied to the liquid crystal of the display unit through a plurality of electrode substrates, the waveform applied to the liquid crystal of the frame unit has a wider range in which a good display is maintained in the distribution of the threshold characteristics of the liquid crystal. Features.

In this case, for example, two light
Higher than the waveform applied to the liquid crystal of the display unit through the polar substrate
The waveform applied to the liquid crystal in the frame is brighter from the dark state of the liquid crystal
Range for maintaining good display in the distribution of threshold characteristics
To be wider. Alternatively , preferably, the frame portion is set to a dark display state, and the waveform given to the liquid crystal in the frame portion is
Good in the distribution of threshold characteristics from the bright state to the dark state
To keep the display range wide. In the latter case,
Preferably, the frame portion has a display luminance of 2 cd / cm ² or less,
Alternatively, dark display is performed so that the transmittance is 0.1% or less. In a preferred embodiment showing the latter aspect, all the pixels on the selected electrodes are set to a dark state as a scan selection signal applied by the driving device when each of the scan electrodes of the scan electrode group and the frame scan electrode are selected. A signal including a reset pulse is used.

[0020]

According to the operation and effect of the present onset bright, since the range of the threshold characteristics can be stably displayed (margin) is driving the frame unit in a broad waveform from the display unit drive waveform for a particular display state,
The frame portion can be set to the specific display state in a wide range with respect to variations in cell thickness and temperature and rough alignment state, and the function as a display device can be enhanced.

Further , when the frame portion is in the dark display state, the difference between the generation of the void portion and the retardation (change in cell thickness) can be hidden, and further, for example, a waveform including a pulse for resetting to the dark state can be provided. By using a waveform having a low threshold value for dark display, the display quality can be maintained for a long period of time without displaying a display defect due to the movement of liquid crystal molecules by displaying a dark portion even in a thick cell portion.

[0022]

Embodiment 1 Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

Here, the present invention is applied to the scanning electrode 1024.
A description will be given of an example in which the present invention is applied to a liquid crystal display device having a liquid crystal panel in which a liquid crystal panel in which a number of information electrodes, 2560 information electrodes, 23 frame scanning electrodes are provided at both ends of a scanning electrode, and 46 frame information electrodes are provided at both ends of an information electrode. I do.

FIG. 1 shows a circuit configuration of a liquid crystal display device according to one embodiment of the present invention. In the figure, 101 is a panel unit, 102 is a display unit, 103a, 103b, 103c are frame units, 105 is a wiring pattern connecting both ends of a frame scanning electrode 203 (see FIG. 2), and 106 is a frame information electrode 206 (FIG. 2).
Reference numeral 107 denotes a scanning signal application circuit, 108 denotes an information signal application circuit, 109 denotes a scanning signal control circuit, 110 denotes an information signal control circuit, 111 denotes a drive control circuit, and 112 denotes a graphic controller.

Data sent from the graphic controller 112 enters the scanning signal control circuit 109 and the information signal control circuit 110 through the drive control circuit 111, and is converted into address data and display data, respectively. At this time,
The data of the frame portion is generated by the drive control circuit 111, but may be generated by the graphic controller 112 in advance. Then, the scanning signal applying circuit 107 generates a scanning signal according to the address data, and the scanning electrode 202 (see FIG. 2) and the frame scanning electrode 203 (see FIG.
See). At this time, the scanning signal applying circuit 107 operates in the same manner as when the number of scanning electrodes is 1024 + 2. Also, the information signal applying circuit 108 according to the display data.
Generates an information signal, and the information electrode 205 of the panel unit 101
(See FIG. 2) and the frame information electrode 206 (see FIG. 2). At this time, the information signal applying circuit 108 has 25 information electrodes.
The same operation as when there are 60 + 2 lines is performed.

FIG. 2 shows an electrode pattern configuration of the panel section 101. In the figure, 1024 scanning electrodes 202 are provided on a scanning side substrate 201, and two frame scanning electrodes 203 are provided at both ends thereof.
There are three each, and a total of 1070 electrodes are arranged in one direction in the same shape. The information side substrate 204 has 2560 information electrodes 205 and 46 frame information electrodes 206 at both ends thereof. A total of 2652 electrodes have the same shape, and when the scanning side substrate 201 and the information side substrate 204 are overlapped, The electrodes on the substrates are arranged side by side in a direction that is perpendicular or nearly perpendicular. A matrix electrode is formed by overlapping the two substrates.

FIG. 3 is a partial sectional view of the panel section 101. In the figure, 301 is an analyzer, 311 is a polarizer, and these are arranged in crossed Nicols. Glass substrates 302 and 310 correspond to the scanning side substrate 201 and the information side substrate 204 in FIG.
9 is a transparent electrode corresponding to the scanning electrode 202 and the frame scanning electrode 203, the information electrode 205 and the frame information electrode 206 in FIG. 2, 304 and 308 are insulating films, 305 and 307 are alignment films, 306 is a ferroelectric liquid crystal, and 312. Is a seal member. The portion indicated by 313 is a pixel serving as a display unit.

FIG. 4 shows driving waveforms used in this embodiment.
In the figure, a waveform A is a scanning selection waveform of the display unit 102, and includes a reset pulse 401, a selection pulse 402, and an auxiliary pulse 403. Reset pulse 4
01 is for darkening all the pixels on the selected scanning electrode 202 (see FIG. 2). Waveform B is a scanning non-selection waveform of the display unit, and the voltage level is zero. Waveform C
Is a scan selection waveform of the frame portion, which is constituted by an auxiliary pulse 404 and a reset pulse 405 for setting all the pixels above the frame scan electrode 203 to a bright state when the frame scan electrode 203 (see FIG. 2) is selected. The waveform D is a scanning non-selection waveform of the frame portion, and the voltage level is zero. A waveform E is a display portion bright information signal when the display portion is scanned, a waveform F is a display portion dark information signal when the display portion is scanned, and a waveform G is a frame information signal when the display portion is scanned. Auxiliary pulse before and after 409-41
3 and the average potential in the unit period is zero. Waveforms H, I, and J are a bright information signal, a dark information signal, and a frame information signal during frame scanning, respectively, and all have a voltage level of zero.

When the frame is being scanned (when the frame is selected)
The voltage of each information signal is set to zero for the following reason. The trouble of generating the display data of the upper and lower frames is eliminated. Reduces power consumption during frame scanning. Avoid continuous drive to improve durability.

The reason why the frame portion is in the bright state is that the visual response to a pulse lower than the threshold value is slower than that in the dark state, and it is difficult to see flicker, flicker, crosstalk, light leakage due to alignment defects, and the like. It is.

FIG. 5 shows a composite waveform for displaying a bright state on the display section and the frame section. In the figure, a waveform K is indicated on a display unit 1.
02 (see FIG. 1), the composite waveform, waveform L
3c (see FIG. 1), the composite waveform, waveform M
3A and 3B (see FIG. 1) are combined waveforms.

FIG. 6 is a plot of the pulse width-transmittance characteristics of the waveforms K, L and M at 30 ° C. In the figure, the thin solid line indicates the characteristic of the waveform K, the thick solid line indicates the characteristic of the waveform L, and the broken line indicates the characteristic of the waveform M.

The measurement is performed gradually from the dark state to the pulse width (ΔT).
And gradually narrowed the pulse width from the middle. The voltages are V ₁ = 10 V, V ₂ = −10 V, V ₃ = 5.
5 V, V ₄ = 5 V, V ₅ = −5 V, and the transmittance was 100% in the bright state.

As is apparent from FIG. 6, a hysteresis phenomenon appears in all of the waveforms K, L and M. That is, the transmittance is different between the case where the pulse width is increased and the case where the pulse width is reduced even with the same pulse width. At this time, comparing the range in which each waveform can stably display the bright state, the waveforms L and M are compared with the waveform K.
Is more stable over a wide range. This is the waveform L,
M means that the range in which good bright display is maintained with respect to variations in threshold characteristics is wider. By expanding the margin of the frame portion, a more stable display can be achieved as a whole of the display device than before.

FIG. 7 shows a conventional drive waveform. 4 differs from that of FIG. 4 only in the waveform G which is a frame information signal at the time of scanning the display section. That is, the waveform G in FIG. 7 is exactly the same as the waveform E, whereas the waveform G in FIG.
An auxiliary pulse 414 corresponding to the auxiliary pulse 410 of the waveform E
Instead, the amplitude of the front auxiliary pulse 413 is set to 2
It has been to V _5. When the drive waveform of FIG. 7 is used in the apparatus of FIG. 1, the margin for the bright display of the frame portion does not increase because the bright information signal (waveform E) and the frame information signal (waveform G) are the same.

FIG. 8 shows another driving waveform used in the present invention. When the panel section 102 of FIG. 1 is driven using this waveform, a margin substantially equal to the case where the driving waveform shown in FIG. 4 is used is obtained. Also, by finely adjusting the values of V ₆ and V ₇ , the range in which good bright display is performed can be adjusted to some extent. However, while the frame information waveform shown in FIG. 4 is composed of ternary voltages of V ₄ , 2V ₅ and zero level, the frame information waveform shown in FIG. 8 is V ₄ , V ₆ , V ₇ and zero level. Therefore, a frame information signal applying circuit (not shown) for handling quaternary values is required separately from a display information signal applying circuit for handling ternary values (see FIG. 1), which increases the cost. .

FIG. 9 is a timing chart of signal transfer between the graphic controller 112 and the drive control circuit 111 of the apparatus shown in FIG. In FIGS. 1 and 9, SYNC is a synchronization signal, and its “L” level means a data transfer request from the drive control circuit 111 to the graphic controller 112. Data is transfer clock 1
4-bit parallel data (PD0 to P
D3) is transferred. Here, the address data and the display data are transferred using the same data bus. AH
/ DL is a signal for identifying the type of data being transferred. The "H" level means that address data is being transferred, and the "L" level means that display data is being transferred.

The ferroelectric liquid crystal used in the above examples contains a pyrimidine component and has the properties shown in the following table.

[0039]

[Table 1] According to the above-described embodiment, by applying a waveform having a wider margin to the display in the bright state than the waveform applied to the liquid crystal of the display unit to the frame, it is possible to maintain good display of the frame.

[0040]

Embodiment 2 A liquid crystal display device similar to that of FIG. 1 was constructed except that the waveform of FIG. 10 was used as a waveform for driving the panel section 102. The waveform of FIG. 10 is different from the waveforms of FIGS. 4 and 7 in a waveform C which is a frame selection scan waveform and a waveform G which is a frame information signal when scanning the display. That is, the waveform C in FIGS. 7 and 4 resets all the pixels on the frame scan electrode 203 (see FIG. 2) to the bright state when the frame scan is selected, whereas the waveform C in FIGS. While the phase is inverted and reset to the dark state, the waveform G in FIGS. 7 and 4 drives the frame portion in the bright state when the display section is scanned.
Waveform G is inverted to reset the waveform A reset pulse 40
In this case, the dark state which has been reset by 1 is maintained.

FIG. 11 shows a composite waveform applied to the liquid crystal.
In the figure, a waveform P is a composite waveform that makes the display unit 102 (see FIG. 1) bright, and a waveform Q is the display unit 102 and the frame unit 10.
3C (see FIG. 1) is a composite waveform for darkening the frames 103a and 103b (see FIG. 1), and a waveform R is a composite waveform for darkening the frames 103a and 103b (see FIG. 1).

As described above, when a voltage is applied for a long time, a portion (a void portion) without liquid crystal is generated at an end of the panel portion 101 (see FIGS. 1 and 15). In this embodiment, since the frame portion is provided, a void is formed in a part of the frame portion, and a thick portion of the cell is formed in the opposite frame portion.

However, in the present embodiment, the following effect is obtained by setting the frame portion to a dark state, and a good display of the frame portion is maintained even if the liquid crystal molecules are moved.

The first effect of this embodiment is that even if a void is generated, it is not visually recognized. That is, in the gap portion of the liquid crystal, light is not polarized, and the analyzer and the polarizer are arranged in crossed Nicols, so that portion looks black. Therefore, in the present embodiment, the frame portion is displayed in black similarly to the gap portion by setting the frame portion to a dark state, and even if a defect occurs, an effect of hiding the defect is provided. However, the liquid crystal molecules in the dark state fluctuate in accordance with the applied electric field, and do not provide perfect black display. Therefore, in order to prevent the difference between the void portion and the dark display portion from being visually recognized, the display brightness of the dark display portion is set to 2.
cd / cm ² or less or the transmittance is 0.1% or less, or the luminance difference between the void portion and the dark display portion is 2 cd / cm ^2.
Or within 0.1%. For this purpose, for example, the following methods (1) to (4) may be used. Reduce the amplitude of the information signal. That is, the amplitude of the information signal in the frame portion is reduced, and the bias ratio defined by V ₄ / (V ₄ −V ₂ ) is set to a value of 1/3 or less, for example, 1/3, 1/3.
If 3.9, 1 / 5.0, etc., the fluctuation of the liquid crystal of the selected pixel is reduced, and the dark display becomes blacker. FIG. 12 shows the transmittance characteristics of the dark display portion when the bias ratio is changed. Optimize analyzer and polarizer positions. The transmittance is also changed by changing the direction of the layer direction between the analyzer and the polarizer and the liquid crystal. FIG. 13 shows transmittance characteristics when the analyzer and the polarizer are fixed to crossed Nicols, and the angle (shift angle) θ between the direction of the layer direction and the polarization direction of the analyzer is changed. In the present embodiment, the darkness was obtained when θ = 9 ° at a temperature of 41 ° C. and a bias ratio of 1 / 3.3. Decrease the brightness of the backlight. A liquid crystal cell having a steep threshold characteristic is used.

The second effect of this embodiment is that the dark display of the frame portion is stable with respect to the change in the cell thickness. That is, as the cell thickness increases, the electric field applied to the liquid crystal weakens,
It is easy to hold the state given by the reset pulse. FIG. 14 shows a temperature of 30 ° C. when the panel 102 having the structure shown in FIGS. 1 to 3 is driven by the composite waveforms P, Q, and R shown in FIG.
4 is a graph showing electric field-transmittance characteristics at the time of FIG. The transmittance is measured from the dark state gradually from the electric field E = (V ₄ −V ₂ ) / d.
(Where d is the cell thickness) was increased, and the electric field was gradually decreased from the middle. In FIG. 14, the characteristic of the waveform P is indicated by a broken line, the characteristic of the waveform Q is indicated by a thin solid line, and the waveform R is indicated by a solid line.
Are shown by the thickest solid line. The voltage shown in FIG. 10 and 11 _{V 1: V 2: V 3} : V 4: V 5 = 23: -2
The ratio was set to 3: 11: 10: -10, and the panel portion 102 was measured using a cell having a cell thickness d of about 1 μm. The transmittance was 100% in the bright state.

As is apparent from FIG. 14, the transmittance of each waveform is different between the case where the electric field is increased and the case where the electric field is decreased even if the same electric field is applied. That is, a hysteresis phenomenon appears. At this time, comparing the range in which the waveform P can stably display the bright state and the range in which the waveforms Q and R can stably display the dark state, the case where the cell thickness becomes thick, that is, the electric field E
Becomes smaller, the waveform P changes from the bright state to the dark state, whereas the waveforms Q and R continue to display the dark state.
In other words, darker display of the frame portion has an effect of expanding the range in which good display is maintained with an increase in cell thickness, as compared with bright display.

Since the waveform R has a wider range in which the dark display can be maintained better than the waveform Q, the frame portion is formed on the frame information electrode side 10.
3c (see FIG. 1) from the frame scanning electrode side 103a, 103b
The effect of bringing the frame portion into a dark state is greater when a defect is caused in (see FIG. 1). Therefore, the rubbing direction is set to -45 ° to 45 ° or 135 ° to 225 with respect to the direction of the scan electrode.
It is desirable to set within the range of °.

A third effect of the present embodiment is that a change in cell thickness (difference in retardation) is not perceived by a viewer as a defect. That is, interference fringes and color unevenness caused by a difference in retardation are noticeable in a bright display, but are difficult to understand in a dark display, and do not feel as a defect.

As described above, in this embodiment, since the frame portion is displayed in a dark state, the difference between the generation of the void and the retardation can be hidden, and a waveform having a low threshold value for the dark display (for example, resetting to the dark state) In this case, a dark portion can be displayed even in a portion where the cell thickness is large, and the display quality can be favorably maintained for a long time without showing a display defect due to movement of liquid crystal molecules.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a liquid crystal display device according to one embodiment of the present invention.

FIG. 2 is a diagram illustrating an electrode configuration of a panel unit in FIG.

FIG. 3 is a sectional view of a panel unit in FIG.

FIG. 4 is a signal waveform diagram used in the apparatus of FIG.

FIG. 5 is a composite waveform diagram of the signal waveforms of FIG.

FIG. 6 is a graph of a pulse width-transmittance characteristic when the panel unit shown in FIGS. 1 to 3 is driven using the waveform of FIG.

FIG. 7 is a diagram showing a conventional signal waveform.

FIG. 8 is a signal waveform diagram according to another embodiment of the present invention.

FIG. 9 is a communication timing chart in the apparatus of FIG. 1;

FIG. 10 is a signal waveform diagram according to still another embodiment of the present invention.

11 is a composite waveform diagram of the signal waveforms of FIG.

FIG. 12 is a graph of a bias ratio-luminance / transmittance characteristic of the panel unit shown in FIGS.

FIG. 13 is a graph showing shift angle-luminance / transmittance characteristics of the panel unit shown in FIGS.

14 is a graph of a pulse width-transmittance characteristic when the panel unit shown in FIGS. 1 to 3 is driven using the waveform of FIG.

FIG. 15 is an explanatory diagram of movement of liquid crystal molecules in a liquid crystal panel.

[Explanation of symbols]

101: panel unit, 102: display unit, 103a, 103
b, 103c: frame portion, 107: scanning signal application circuit, 10
8: information signal application circuit, 109: scanning signal control circuit, 1
10: information signal control circuit, 111: drive control circuit, 11
2: graphic controller, 201: scanning side substrate,
202: scanning electrode, 203: frame scanning electrode, 204: information side substrate, 205: information electrode, 206: frame information electrode, 30
1: analyzer, 311: polarizer, 302, 31
0: glass substrate, 303, 309: transparent electrode, 304,
308: insulating film, 305, 307: alignment film, 306: ferroelectric liquid crystal, 312: sealing member, 401, 405, 4
06 to 408: reset pulse, 402,: selection pulse, 403, 404, 409 to 414: auxiliary pulse.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G09G 3/36 G02F 1/133

Claims (9)

(57) [Claims] 1. A liquid crystal having a smectic layer structure and having a memory property is disposed between an electrode substrate having a scanning electrode group and an electrode substrate having an information electrode group, and a first stability by the liquid crystal is provided. A matrix display element forming a display portion for displaying a state and a second stable state, and forming a frame portion by arranging a frame scanning electrode and a frame information electrode outside the scanning electrode group and the information electrode group; A signal waveform corresponding to the display content is applied to the liquid crystal of the display section via the two electrode substrates, and the liquid crystal of the frame section has a liquid crystal for one of the two stable states of the liquid crystal. A liquid crystal display device comprising: a driving device for applying a signal waveform whose range for maintaining good display in the distribution of the threshold characteristics is wider than the signal waveform applied to the liquid crystal of the display unit. 2. The two stable states of the liquid crystal in the display element are a bright state and a dark state, and the signal waveform applied to the liquid crystal in the frame portion via the two electrode substrates by the driving device is as described above. The signal waveform applied to a liquid crystal of the display unit has a wider range in which a range in which a good display in a bright state is maintained in a distribution of threshold characteristics from a dark state to a bright state of the liquid crystal. 2. The liquid crystal display device according to 1. 3. A signal waveform applied when each of the scanning electrodes of the scanning electrode group is selected includes a reset pulse for setting the liquid crystal in a dark state, a scanning selection pulse for setting a display state of a display unit, and a scanning auxiliary pulse. And the signal waveform applied to each information electrode of the information electrode group is the scan selection for setting a pixel formed at the intersection of the selected scan electrode and each information electrode to a desired stable state. A signal waveform applied to the frame information electrode, comprising: an information selection pulse synchronized with the pulse; and an information auxiliary pulse added before and after the information selection pulse to make the average potential of the information selection pulse zero. Is a frame selection pulse synchronized with the selection pulse for making the frame pixel formed at the intersection with the selected scan electrode bright, and the frame selection pulse added before and after the frame selection pulse. And an information auxiliary pulse before and after the information selection pulse has substantially the same pulse width and pulse amplitude as each other, and a frame auxiliary pulse before and after the frame selection pulse is used. pulse pulse width substantially the same as the information auxiliary pulse, the flat
3. The liquid crystal display device according to claim 2, wherein the amplitude from the equalizing potential is smaller in the rear frame auxiliary pulse than in the front frame auxiliary pulse. 4. The amplitude of the rear frame auxiliary pulse from the zero potential is zero, and the amplitude of the front frame auxiliary pulse is twice the amplitude of the information auxiliary pulse. 3. The liquid crystal display device according to 3. 5. A signal waveform applied when the frame scanning electrode is selected includes a frame scanning auxiliary pulse and a reset pulse for setting all the pixels formed on the frame scanning electrode to a bright state. Item 5. The liquid crystal display device according to any one of Items 2 to 4. 6. The liquid crystal display device according to claim 1, characterized in that the dark display state before Symbol frame portion. 7. The liquid crystal display device according to claim 6, wherein the display brightness of the frame portion is 2 cd / cm ² or less. 8. The liquid crystal display device according to claim 6, wherein the transmittance of the frame portion is 0.1% or less. 9. A scanning selection signal applied by the driving device when selecting each of the scanning electrodes of the scanning electrode group and the frame scanning electrode includes a pulse for resetting all pixels on the selected electrode to a dark state. 7. The liquid crystal display device according to claim 6, wherein: