JPH10104581A - Liquid crystal device and electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify a Y driver used for a charge-discharge drive method, etc., and to miniaturize a liquid crystal device by driving using a voltage outputted by beforehand switching a binary voltage among the voltages used in a drive method discharging to a proper voltage after pixel capacity is charged to an excess voltage with a switch circuit. SOLUTION: The drive is performed by using the voltage beforehand switching the binary voltage among the voltages used in the drive method discharging to the proper voltage after the pixel capacity constituting a liquid crystal element is charged to the excess voltage with the switch circuit. For instance, in the liquid crystal device, the Y driver 13 consists of plural switch circuits selecting one voltage among the voltage Vs outputted by the switch circuit 12, a precharge voltage -Vpre outputted by a power source circuit 11 and a binary non-selective voltage ±Vsig/2, and respectively outputting them to the scan electrodes Y1-Y5 of the liquid crystal element 10. Then, the Y driver 13 is controlled by control signals Sy1, Sy0, YSCL and LP among a control signals group 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a liquid crystal device and an electronic apparatus using the same.

[0002]

2. Description of the Related Art In recent years, liquid crystal devices have been used particularly as display devices.
As a lightweight display device with low power consumption, it is widely used in electronic devices such as televisions, electronic organizers, personal computers, and mobile phones. And recently, MIM
In a so-called two-terminal active matrix liquid crystal device using a non-linear resistance element such as an element, a back-to-back diode element, a diode ring element, and a varistor element, a first selection voltage for applying a first selection voltage to a scanning electrode is provided. A new driving method (charge / discharge driving method) in which a liquid crystal element is driven by mixing a mode and a second mode in which a second selection voltage is applied to a scan electrode after a precharge voltage is applied is being spotlighted. is there. The charge / discharge driving method is disclosed in, for example, Japanese Patent Application Laid-Open No. 2-125225. In addition,
In the embodiment of 2-125225, a third voltage having a polarity opposite to the first selection voltage is used.
A third mode in which the selection voltage is applied to the scan electrodes, and a fourth mode in which the polarity is opposite to the second selection voltage after the precharge voltage is applied.
A method is disclosed in which the fourth mode of applying the selection voltage to the scan electrode is mixed and driven in addition to the first and second modes. (A method in which only the first and second modes are mixed and driven is a unipolar charge / discharge driving method.
The method of adding the above modes and driving them in a mixed manner is called a bipolar charge / discharge driving method. On the other hand, a driving method called a quaternary driving method using a binary selection voltage and a binary non-selection voltage, which is prior to the charge / discharge driving method, is also known.

Since the number of levels of the non-selection voltage is not directly related to the present invention, a detailed description thereof will be omitted. However, it is not always necessary to use two values as in the cited example, and it may be one value or more than three values.

A quaternary driving method using a binary non-selection voltage and a charging / discharging driving method will be briefly described with reference to FIGS.

FIG. 2 is a schematic diagram showing one configuration example of a two-terminal type active matrix liquid crystal element. FIG. 18 is a view showing an electric equivalent circuit per pixel of the liquid crystal element of FIG.
FIG. 20 is a diagram showing a driving waveform of the quaternary driving method, FIG. 20 is a diagram showing a driving waveform of the unipolar charging / discharging driving, and FIG. 21 is a diagram showing a driving waveform of the bipolar charging / discharging driving.

In FIG. 2, reference numeral 10 denotes a two-terminal type active liquid crystal element, and reference numerals 1 and 2 denote a pair of substrates sandwiching a liquid crystal layer (not shown). If necessary, deflection plates (not shown) are provided on both surfaces. Is attached. Y1 to Y5 are a plurality of scanning electrodes provided on the substrate 1, and X1 to X5 are signal electrodes provided on the substrate 2.

S is a non-linear resistance element, which is represented by a symbol at only one place in FIG.
It is provided at each intersection of the signal electrodes X1 to Y5 and the signal electrodes X1 to X5. In this embodiment, as the nonlinear resistance element S, an MIM element in which a thin insulating film is formed between metals is used, but any element having bidirectional diode characteristics may be used. P is a pixel electrode, which is represented by a symbol at only one place in the figure, but is provided so as to be connected to each of the nonlinear resistance elements S. In this embodiment, the non-linear resistance element S and the pixel electrode P are provided on the substrate 1, but may be provided on the substrate 2.

One pixel is formed by the non-linear resistance element S, the pixel electrode P connected to the non-linear resistance element S, and the opposing portion of the pixel electrode P and the signal electrode. Pixels formed at respective intersections of the signal electrodes X1 and X2 are denoted by symbols of the pixels 1 and 2. Then, a pixel capacitor is formed in which each of the signal electrodes X1 to X5 and the pixel electrode P opposed thereto are used as electrodes, and the liquid crystal layer is used as a dielectric.

Further, here, the voltage applied to the pixel capacitance
It is assumed that the deflecting plate is attached so that the transmittance decreases as the (pixel voltage) increases, that is, a normally white state is set.

In this embodiment, the number of the scanning electrodes Y1 to Y5 and the number of the signal electrodes X1 to X5 are as small as five. However, in order to simplify the drawing and the explanation, an actual liquid crystal panel usually has several hundreds or more. Consists of a number of

FIG. 18 is a diagram showing an electric equivalent circuit of one pixel in FIG. 2, where Rs is the resistance of the nonlinear resistance element S in FIG. 2 and Cp is the pixel capacitance made by the pixel in FIG. The nonlinear resistance element is
Generally, there is a threshold voltage at which voltage is applied to both ends (this voltage is referred to as Vt
h. ) Or lower, the resistance becomes high, and above this threshold voltage, the resistance becomes low.

Therefore, when a voltage Vin higher than the threshold voltage is applied between the scan electrodes Y1 to Y5 and the signal electrodes X1 to X5, the pixel capacitance is charged and the voltage increases through the low-resistance non-linear resistance element. However, when the voltage reaches Vin−Vth, the voltage applied to the non-linear resistance element becomes Vth, the non-linear resistance element has a high resistance, and charging is stopped.

Accordingly, the pixel voltage becomes Vin-Vth. The threshold voltage varies depending on the size and type of the non-linear resistance element, but is, for example, about ten and several volts in the case of the MIM element.

FIG. 19 is a diagram showing driving waveforms in the four-value driving method, in which voltage waveforms applied to the scanning electrode Y1 on behalf of the scanning electrodes Y1 to 5 of the liquid crystal element 10 in FIG. 2 are shown by solid lines.
In the drawing, t1 to 5 and T1 to 5 are scanning electrodes Y1 to Y1, respectively.
Reference numeral 5 denotes a selected period, and all the scan electrodes are sequentially selected. A period of one cycle is called a frame period. In the figure, two consecutive frame periods are defined as one frame and two frames. The voltage waveform applied to the pixel capacitance of the pixel 1 is indicated by hatching. It should be noted that the voltage waveform applied to all the signal electrodes X1 to X5 is set to a constant 0V in order to simplify the description.

As shown in FIG. 19, the voltage waveform applied to the scanning electrode is a selection voltage having an equal absolute value and a different polarity with respect to the voltage (0 V) applied to the signal electrode (this is referred to as ± Vs1). And non-selection voltage of same polarity and different polarity
(This is ± Vsig / 2). Here, the absolute value of the selection voltage is set to be larger than the threshold voltage Vth of the nonlinear resistance element, and the absolute value of the voltage is set to be smaller than the threshold voltage Vth of the non-linear resistance element when it is not selected.

In the first frame, a voltage of + Vs1 is applied when the odd-numbered scan electrodes Y1, 3, and 5 are selected, and a voltage of -Vs1 is applied when the even-numbered Y2 and Y4 are selected. The opposite is true for the second frame. Then, the non-selection voltage of + Vsig / 2 is continuously applied to the scanning electrode to which + Vs1 is applied during the selection period until the next selection period, and -Vsig / 2 is applied during the selection period.
After that, the non-selection voltage of -Vsig / 2 is continuously applied to the scan electrode to which Vs1 has been applied until the next selection period.

By applying the selection voltage (± Vs1) in each selection period by such driving, the pixel voltage of the pixel 1 becomes ± (Vs1−Vth), and the voltage is maintained after the selection is completed. Therefore, the effective voltage of the pixel 1 is Vs1−Vth, and the transmittance of the pixel 1 is a transmittance corresponding to the effective voltage.

By the way, the threshold voltage of the non-linear resistance element also varies due to the manufacturing variation or the like. Therefore, for example, the threshold voltage of the nonlinear resistance element of the pixel 2 is
In this case, the effective voltage of the pixel 2 becomes Vs1− (Vth + ΔV), which is lower than that of the pixel 1, and the transmittance increases accordingly.

In other words, display unevenness occurs due to variation in the threshold voltage of the nonlinear resistance element of each pixel of the liquid crystal element.

FIG. 20 is a diagram showing driving waveforms in the unipolar charge / discharge driving method. The symbols in the drawing are the same as those in FIG.

The voltage waveforms applied to the scanning electrodes are different selection voltages (these voltages are referred to as Vs1 and Vs2), a precharge voltage (-Vpre) of the opposite polarity, and a binary non-selection voltage (this Is ± Vsig / 2). Here, the absolute value of the voltage in the selection voltage and the precharge is set higher than the threshold voltage Vth of the non-linear resistance element, and the absolute value of the non-selection voltage is set lower than the threshold voltage Vth of the non-linear resistance element.

Here, the scanning electrodes Y1 to Y5 are sequentially selected, and in each selection period, the first mode in which the first selection voltage (Vs1) is applied and the first precharge voltage (-Vpre) are applied. Later, a voltage is alternately applied in any mode as a second mode in which a second selection voltage (Vs2) is applied,
After the selection is completed, a non-selection voltage of + Vsig / 2 or -Vsig / 2 is applied.

Accordingly, the pixel voltage of the pixel 1 is first set in the same manner as in the four-value driving method in the first mode. The pixel capacitance is charged by applying the first selection voltage (Vs1), and the pixel voltage is set to V.
s1−Vth.

On the other hand, in the second mode, the pixel voltage is set to-(Vpre-Vth) by applying a precharge voltage (-Vpre) first. Here, the absolute value of the precharge voltage is set to be sufficiently large, and-(Vpre-Vt
The absolute value of h) is also a sufficiently large value.

The pixel capacitance is overcharged by applying a precharge voltage. Then, after that, the second selection voltage Vs2 is applied, and discharge is performed so that the pixel voltage becomes Vth-Vs2.

Here, the voltage Vs2 is calculated as follows: Vs2 = 2 · Vth−Vs1
By setting, the absolute value of Vth−Vs2 and Vs1−V
th has the same absolute value, and the effective voltage at this time is also Vs1−V
It becomes th. That is, the effective voltage is the same as in the four-value driving method.
That is, in the second mode, after the pixel capacitance is excessively charged by applying the precharge voltage, the second selection voltage V
Applying s2 until the pixel voltage becomes the proper value
In this mode, the electric charge is discharged from the pixel capacitance.

By the way, when the threshold voltage of the nonlinear resistance element of the pixel 2 is higher than that of the pixel 1 by ΔV due to manufacturing variation or the like, the pixel voltage of the pixel 2 becomes Vs1− (Vth + ΔV) in the first mode. , But in the second mode, (Vth + ΔV) −Vs2, which is higher than pixel 1. Therefore, when viewed as an effective voltage, the effective voltage is substantially the same as the effective voltage of the pixel 1, and even if the threshold voltage of the nonlinear resistance element of each pixel of the liquid crystal element varies, display unevenness hardly occurs. However, a DC component of 2ΔV is applied to the pixel capacitance.

FIG. 21 is a diagram showing driving waveforms in the bipolar charge / discharge driving method, and a solid line represents a voltage waveform applied to the scanning electrode Y1 of the liquid crystal element 10 in FIG.

In the bipolar charging / discharging driving method, the 1 frame and the 2 frame shown in the figure are repeated a plurality of times, and then the a frame and the b frame are repeated a plurality of times.

Here, the repetition of one frame and two frames is the unipolar charge / discharge drive described above, and
The frame is repeatedly driven by using voltages obtained by inverting the polarities of the respective voltages constituting the unipolar charge / discharge drive. That is, the second mode using the voltage -Vs1 as the third selection voltage, the voltage Vpre as the second precharge voltage, the voltage -Vs2 as the fourth selection voltage, and the second mode.
Is a driving method in which each of the scan electrodes is alternately selected in any one of the fourth modes in which the fourth selection voltage is mixed after the precharge voltage is applied.

Therefore, as in the unipolar charge / discharge driving, display unevenness hardly occurs, and the polarity is inverted, so that no DC component is applied to the pixel capacitance.

[0032]

As described above, the charge / discharge driving method has various advantages in that the display characteristics can be improved as compared with the quaternary driving method. However,
In the quaternary driving method, a scanning electrode driving means or a voltage output means (Y driver) for supplying these voltages to a plurality of scanning electrodes is a quaternary voltage per scanning electrode, that is, a binary selection voltage (Y-driver). ± Vs1) and binary non-selection voltage (± Vsig / 2),
In contrast, in the unipolar charge / discharge driving method, a five-valued voltage, that is, a two-valued selection voltage (Vs1 and Vs2) and a two-valued non-selection voltage can be used. (± Vsig /
2) and one of the one-valued precharge voltage (-Vpre) must be selected and output. Further, in the bipolar charge / discharge driving method, an eight-valued voltage, that is, a four-valued voltage is used. Select voltage
(± Vs1 and ± Vs2), one of the binary non-selection voltage (± Vsig / 2), and the binary precharge voltage (± Vpre) must be selected and output.

In general, the number of scanning electrodes constituting a liquid crystal element is as large as 100 or more. Therefore, if the number of voltages output from each scanning electrode is increased even by one value, the circuit configuration becomes extremely complicated as a whole. Further, the absolute values of the selection voltage and the precharge voltage are high voltages of about 10 to 30 V, and a circuit structure with a high withstand voltage is required. Therefore, the Y driver used in the charge / discharge driving method is considerably more complicated than the Y driver used in the quaternary driving method, and there is a problem that the Y driver becomes expensive and the outer shape becomes large.

The present invention has been made in view of the above-described problems, and has as its object to simplify a Y driver used in a charge / discharge driving method and the like, to provide a liquid crystal device and a liquid crystal device including the same. It is an object of the present invention to provide an electronic device that is inexpensive, small, and lightweight.

[0035]

According to a first aspect of the present invention, there is provided a liquid crystal device comprising: a plurality of scanning electrodes formed on one of a pair of substrates sandwiching a liquid crystal layer; A plurality of signal electrodes are formed on the other substrate so as to intersect with the electrodes of the scan electrode, and a non-linear resistance element and a pixel electrode are formed at each intersection of the scan electrode and the signal electrode. A liquid crystal element in which a pixel is formed by the scanning electrode or the signal electrode facing an electrode,
A signal electrode driving means for applying a pulse width or a voltage-modulated signal voltage waveform to each of the plurality of signal electrodes; and, in a first mode, applying a first selection voltage to each of the plurality of scan electrodes. In the mode, a first precharge voltage having a polarity opposite to that of the first selection voltage is applied to the center voltage of the signal voltage waveform, and then the first precharge voltage is set with reference to the center voltage of the signal voltage waveform. In a liquid crystal device including a scan electrode driving unit for applying a second selection voltage having a polarity opposite to a charge voltage to each of the plurality of scan electrodes, the scan electrode driving unit includes the first selection voltage and the second selection voltage. A first voltage switching unit for switching a voltage, and selecting one of the voltage output by the first switching unit, the first precharge voltage, and one or a plurality of non-selection voltages to perform each of the plurality of scans Electric Characterized by comprising a voltage output means for providing a.

The liquid crystal device of the present invention can be applied to a liquid crystal device driven by a so-called unipolar charge / discharge driving method. Further, according to the present invention, the configuration of the Y driver is configured by changing the voltage of one of the first selection voltage and the second selection voltage, the precharge voltage, and the one or more non-selection voltages output by the voltage switching means. Switch for selecting and outputting one of the voltages.

According to a second aspect of the present invention, there is provided a liquid crystal device having a third mode in addition to the liquid crystal element according to the first aspect, the signal electrode driving means, the first mode and the second mode. In the method, a third selection voltage having a polarity opposite to the first selection voltage with respect to a center voltage of the signal voltage waveform is applied to each of the plurality of scan electrodes, and in a fourth mode, the third selection voltage is applied to the signal voltage waveform. After applying a second precharge voltage having a polarity opposite to the third selection voltage with respect to the center voltage, a fourth selection having a polarity opposite to the second precharge voltage with respect to the center voltage of the signal voltage waveform. In a liquid crystal device including a scanning electrode driving unit for applying a voltage to each of the plurality of scanning electrodes, the scanning electrode driving unit includes the first selection voltage and the second selection voltage.
Second voltage switching means for switching between the first selection voltage and the second precharge voltage, and third voltage switching means for switching between the third selection voltage, the fourth selection voltage, and the first precharge voltage And voltage output means for selecting one of the voltage output from the second voltage switching means and the third voltage switching means and the non-selection voltage and applying the selected voltage to each of the plurality of scan electrodes. And

The liquid crystal device of the present invention can be applied to a liquid crystal device driven by a so-called bipolar charge / discharge driving method. Then, according to the present invention, the configuration of the Y driver is changed to any one of the first selection voltage, the second selection voltage, and the second precharge voltage output by the first voltage switching means,
Selects any one of the second selection voltage, the fourth selection voltage, the first precharge voltage, and one or more non-selection voltages output by the second voltage switching means. , And a switch configuration for output.

According to a third aspect of the present invention, in the liquid crystal device according to the first aspect, the first voltage switching means is provided on the same integrated circuit together with the voltage output means. It is characterized by the following.

The liquid crystal device of the present invention can be applied to a liquid crystal device driven by a so-called unipolar charge / discharge driving method. According to the present invention, by including the voltage switching means in the configuration of the Y driver using the integrated circuit, the space for providing the voltage switching means can be reduced.

According to a fourth aspect of the present invention, in the liquid crystal device of the second aspect, the second to third voltage switching means are provided on the same integrated circuit together with the voltage output means. It is characterized by having been done.

The liquid crystal device of the present invention can be applied to a liquid crystal device driven by a so-called unipolar charge / discharge driving method. According to the present invention, by including the voltage switching means in the configuration of the Y driver using the integrated circuit, the space for providing the voltage switching means can be reduced.

According to a fifth aspect of the present invention, there is provided the liquid crystal device according to the first aspect, wherein the power supply voltage for driving the voltage output means is changed by a change in the voltage output by the first voltage switching means. It is characterized by changing according to.

The liquid crystal device of the present invention can be applied to a liquid crystal device driven by a so-called unipolar charge / discharge driving method. According to the present invention, the withstand voltage of the switch of the Y driver can be reduced to a voltage obtained by adding several V to the precharge voltage at most.

According to a sixth aspect of the present invention, in the liquid crystal device according to the second aspect, the power supply voltage for driving the voltage output means is a voltage output by the second or third voltage switching means. It is characterized in that it changes in response to a change in.

The liquid crystal device of the present invention can be applied to a liquid crystal device driven by a so-called bipolar charge / discharge driving method. According to the present invention, the withstand voltage of the switch of the Y driver can be reduced to a voltage obtained by adding several V to the precharge voltage at most.

According to a seventh aspect of the present invention, there is provided an electronic apparatus including the liquid crystal device according to the first to sixth aspects. By doing so, it is possible to improve the display characteristics of a liquid crystal device as a display device used for electronic devices such as a television, a remote controller, a calculator, a mobile phone, a portable information device, a projector, and a personal computer, and reduce costs. In addition, it is possible to reduce the size and weight.

[0048]

Embodiments of the present invention will be described below with reference to the drawings.

[Embodiment 1] This embodiment relates to the first aspect of the present invention, and FIG. 1 is a diagram showing an example of the configuration of a liquid crystal device according to the present invention.

In FIG. 2, reference numeral 10 denotes a liquid crystal element. FIG. 11 is a power supply circuit, and 12 is a switch circuit. Reference numeral 13 denotes a scanning electrode driving circuit (referred to as a Y driver), and FIG. 14 is a signal electrode drive circuit
(Referred to as X driver). Reference numeral 15 denotes a control signal group.
Reference numeral 16 denotes a ground voltage (0 V).

Before giving a detailed description of FIG. 1, first, a specific driving waveform of the unipolar charge / discharge driving method and a basic concept of the present embodiment will be described.

In the unipolar charge / discharge driving method, there is a certain degree of freedom in setting the time for applying the first selection voltage, the second selection voltage, and the precharge voltage, so that the driving waveform applied to the scanning electrodes differs. . Here, five scanning electrodes Y
The driving waveform will be described by taking a liquid crystal element having 1 to Y5 as an example. FIG. 4 is a diagram illustrating an example of a driving waveform.

In the figure, VY1 to VY5 are scanning electrodes Y1 respectively.
To Y5. In the figure, t1
-5, and T1-5 indicate periods during which each of the scan electrodes Y1-5 is selected, and each of the periods is referred to as a 1H period. Then, all the scanning electrodes are sequentially selected, a period of one cycle is called a frame period, and the following two frame periods are one frame and two frames as shown in the figure.

In the first frame, when the odd-numbered scan electrodes Y1, 3, and 5 are selected, the first mode, that is, the first selection voltage (Vs1) is applied for 1H period, and the even-numbered Y is applied.
When 2 and 4 are selected, the first precharge voltage (-Vpre) is applied for 1H period before the 1H period, and the second selection voltage (Vs2) is applied for 1H period in the selection period.
That is, the selection is made in the second mode. And
In the second frame, each scanning electrode is selected in the reverse mode.

Then, during the selection period, the first selection voltage (Vs1)
The non-selection voltage of + Vsig / 2 is continuously applied to the scan electrode to which the voltage is applied until the next selection period, and the non-selection voltage of -Vsig / 2 is subsequently applied to the scan electrode to which Vs2 is applied during the selection period. The application is continued until the selection period.

The waveforms of one frame and two frames are repeated.

In this example, the period during which Vs1 or Vs2 is applied is a 1H period, and a method of driving with such a drive waveform is called a 1H write driving method.

FIG. 5 is a diagram showing another example of the driving waveform.

The reference numerals in the figure are the same as those in FIG. In the first frame, the odd-numbered scan electrodes Y1, 3, 5
Is selected in the first mode, ie, the first selection voltage.
(Vs1) is applied for 0.5H during the latter half of each selection period, and when even numbers Y2 and 4 are selected, the first half 0.5H of the selection period is applied.
The first precharge voltage (-Vpre) is applied during the period, and the second selection voltage (Vs2) is applied during the second half 0.5H period. Then, in the second frame, each scanning electrode is selected in the reverse mode.

FIG. 4 shows how to apply the non-selection voltage. The waveforms of one frame and two frames are repeated.

In this example, the period during which the voltage Vs1 and the voltage Vs2 are applied is 0.5H, respectively, and the method of driving with such a drive waveform is called the 0.5H write driving method.

FIG. 6 is a diagram showing still another example of the driving waveform.

The reference numerals in the figure are the same as those in FIG. In the first frame, the odd-numbered scan electrodes Y1, 3, 5
Is selected in the first mode, ie, the first selection voltage.
(Vs1) is applied for 1H period of each selection period, and even-numbered Y2,
4 is selected, the first precharge voltage (-Vpre) is applied in the 1.5H period from 1.5H period before the selection period, and the second selection voltage (Vs2) is applied in the 1H period in the selection period. Apply. Then, in the second frame, each scanning electrode is selected in the reverse mode.

FIG. 4 shows how to apply the non-selection voltage. The waveforms of one frame and two frames are repeated.

In this example, the period during which the precharge voltage is applied in the 1H write driving method shown in FIG.
This is a driving method extended in the H period.

As described above, in the charge / discharge driving method, there is a certain degree of freedom in setting the period for applying each voltage. In general, the period for applying the selection voltages Vs1 and Vs2 is set to 1H or less.
The period during which the precharge voltage (-Vpre) is applied is set to be approximately the same as the period during which the selection voltages Vs1 and Vs2 are applied, to about several H periods.

FIGS. 4 to 6 show examples of several types of driving waveforms for unipolar charge / discharge driving. As can be seen from FIGS. 4 to 6, in any case of the driving waveforms, the first selection voltage (Vs1) and It can be seen that the second selection voltage (Vs2) is not applied to the scan electrodes Y1 to Y5 at the same time. The present invention has been made focusing on this point.

That is, a switch circuit for selecting one of the voltage Vs1 and the voltage Vs2 is provided in advance, and the output of the switch circuit is set to the voltage Vs, so that the switch of the Y driver circuit for supplying the voltage waveform applied to the scanning electrode of the liquid crystal element is provided. The configuration can be simplified to a switch configuration for selecting and outputting one of four values of the voltage Vs, ± Vsig / 2, and -Vpre.

Here, returning to FIG. 1, a specific configuration will be described.

FIG. 2 shows a detailed configuration example of the liquid crystal element 10 shown in FIG.
Shown in FIG. 2 is a schematic diagram showing an example of the configuration of a two-terminal active matrix liquid crystal element 10.
(Not shown). Y1 to Y5 are a plurality of scanning electrodes provided on the substrate 1, and X1 to X5 are signal electrodes provided on the substrate 2.

S is a non-linear resistance element, which is represented by a symbol at only one place in FIG.
It is provided at each intersection of the signal electrodes X1 to Y5 and the signal electrodes X1 to X5. In this embodiment, as the nonlinear resistance element S, an MIM element in which a thin insulating film is formed between metals is used, but any element having bidirectional diode characteristics may be used. P is a pixel electrode, which is represented by a symbol at only one place in the figure, but is provided so as to be connected to each of the nonlinear resistance elements S. In this embodiment, the non-linear resistance element S and the pixel electrode P are provided on the substrate 1, but may be provided on the substrate 2.

One pixel is formed by the non-linear resistance element S, the pixel electrode P connected thereto, and the portion where the pixel electrode P and the signal electrode are opposed to each other. Pixels formed at respective intersections of the signal electrodes X1 and X2 are denoted by symbols of the pixels 1 and 2.

Although the number of scanning electrodes and signal electrodes is as small as five, each is generally several hundred in order to simplify the explanation.

In FIG. 1, the power supply circuit 11 sets the first selection voltage Vs1, the second selection voltage Vs2, and the precharge voltage to -Vpr.
e and the binary non-selection voltage ± Vsig / 2 and the power supply voltages VDDHY and VDDY required to drive the Y driver 13 and the power supply voltage Vx required to drive the X driver 14 are generated.
Since these voltages are constant voltages and can be easily embodied, a detailed description of the configuration will be omitted.

The switch circuit 12 has a first selection voltage Vs1.
And a switch that selects one of the second selection voltage Vs2 and outputs the selected voltage as Vs.
In this case, Vs1 is selected when Ss = "1", and Vs2 is selected when Ss = "0".

The Y driver 13 selects one of the voltage Vs output from the switch circuit 12, the precharge voltage -Vpre output from the power supply circuit 11, and one of the two non-selection voltages ± Vsig / 2. Scanning electrodes Y1-5 of liquid crystal element 10
Control signal group 1
5 are controlled by control signals Sy1, Sy0, YSCL, and LP.

FIG. 3 shows a detailed configuration example of the Y driver 13.

In FIG. 3, reference numeral 301 denotes a 2-bit × n-bit shift register; 302, a 2-bit × n-bit latch circuit; and 303, n 4-input / 1-output switch circuits. Here, n is the number of scanning electrodes, which is 5 in this embodiment, but n is actually several tens to several hundreds. Also, Y driver 1
Reference numeral 3 generally comprises one or a plurality of integrated circuits.

The shift register 301 takes in the control signals Sy1 and Sy0 in synchronization with the control signal YSCL, which is a clock signal, and shifts the signals from top to bottom. Here, the control signal Sy1,
In Sy0, the state of “0,0” is 0, the state of “0,1” is 1, the state of “1,0” is 2, and the state of “1,1” is 3. Latch circuit 302
Captures the state of the corresponding bit in the shift register 301 in synchronization with the control signal LP.

The switch circuit 303 has a voltage input terminal V0
To Vs, + Vsig / 2, -Vsig / 2,-
One of the four voltages Vpre is selected and output according to the state of the bit of the corresponding latch circuit 302. Here, when the bit state of the corresponding latch circuit 302 is 3, the voltage at the V3 terminal is -Vpre, and when the bit state is 2, the voltage at the V2 terminal is-
When Vsig / 2, 1, V1 terminal voltage + Vsig / 2, when 0, V0
It is assumed that the terminal voltage Vs is selected.

The voltage VDDY is applied to the level shifter circuit 30.
1. The power supply voltage and voltage VDDH for driving the logic circuit of the latch circuit 302 are power supply voltages for driving the switch circuit 303. Further, GNDY is the ground voltage of the Y driver 13, and in this embodiment, the ground voltage 16 of the power supply circuit 11 of FIG.
(0 V).

Accordingly, by appropriately changing the control signals Sy1 and Sy0 in synchronization with the control signal YSCL for n clocks, 0 to 0 bits are stored in the 2-bit × n-bit shift register 301.
3 can be taken in, and then the control signal
By taking in the 2-bit × n-bit shift register value into the 2-bit × n-bit latch circuit 302 by LP, a voltage corresponding to an arbitrary value of 0 to 3, ie, Vs,
The voltage of either ± Vsig / 2 or -Vpre is applied to the liquid crystal element 1 of FIG.
0 is supplied to each of the scanning electrodes Y1 to Y5.

The Y driver 13 is the X driver 1 shown in FIG.
Reference numeral 4 denotes a circuit for outputting a signal voltage waveform having a pulse width or a voltage modulated to each of the signal electrodes X1 to X5 of the liquid crystal element 10, and is controlled by a plurality of control signals Sx in the control signal group 15. Since the specific configuration of the X driver 14 does not directly relate to the present invention, no further description will be given.

The control signal group 15 includes a control signal Ss for controlling the switch circuit 12, control signals Sy1, Sy0, YSCL and LP for controlling the Y driver 13, and a plurality of control signals Sx for controlling the X driver 14. Although it is made of a circuit (not shown) or the like, this specific configuration is not directly involved in the present invention and will not be described further.

The structure of the liquid crystal device according to the first embodiment is as described above.

Next, the operation of the liquid crystal device will be described.

FIG. 7 is a diagram showing the voltage waveforms of the scanning electrodes Y1 and Y2 and the timing of some signals of the control signal group 15 for explaining the operation. In the figure, t1 to t5, T1 to T5,
And the first and second frames are the same as those described in FIG. VY1 and VY2 indicate the voltage waveforms of the scan electrodes Y1 and Y2, the waveforms of the control signals Ss, YSCL, and LP in the control signal group 15, and the numerical values represented by the two bits Sy1,0 of the control signals Sy1, Sy0. Is shown.

In the figure, the control signal Ss has a period t1, 3, t
It becomes 1 at 5, T2 and T4, and becomes 0 at other periods, and the switch circuit 12 of FIG.
2. At T4, Vs1 is output as Vs, and Vs2 is output during other periods.

As shown in FIG. 7, in synchronization with the five clocks of the control signal YSCL, the control signals Sy1 and Sy0 are taken into the shift register circuit 301 of the Y driver 13 in FIG. 3 and shifted. The control signal LP becomes 1 at a rate of one for every five control signals YSCL, the data is taken into the latch circuit 302, and at the same time, the switch circuit 303 selects a voltage corresponding to the data, and the liquid crystal shown in FIG. The scanning electrodes Y1 to Y5 of the element 10 are used.

More specifically, as shown in FIG. 4, the control signal YSCL is generated 1H before the period t1, that is, during the period T5.
In synchronization with the control signals Sy1, Sy0, 2, 1, 2, 3,
The values change in the order of 0, and are taken into the shift register circuit 301 of the Y driver 13 in FIG. Therefore, when the fifth control signal YSCL is output, the data at the position corresponding to the scan electrodes Y1 to Y5 of the shift register circuit 301 is 0,
3, 2, 1, and 2.

This data is taken into the latch circuit 301 in synchronization with the control signal LP. Therefore, the data at the positions corresponding to the scan electrodes Y1 to Y5 of the shift register circuit 301 are also 0, 3, 2, 1, and 2 data. Accordingly, the voltage output from the switch circuit 303 is applied to the scan electrode Y1 by V
s, that is, -Vpre for Vs1, Y2, -Vsig / 2, Y4 for Y3.
+ Vsig / 2 and -Vsig / 2 at Y5, and this voltage is output during the period t1.

Similarly, during this period t1, the next t2
The voltage data to be output during the period is captured. That is, as shown in FIG. 7, the control signals Sy1 and Sy1 are synchronized with the control signal YSCL.
y0 changes in the order of 2, 1, 2, 0 and 1, and is taken into the shift register circuit 301 of the Y driver 13 in FIG.
Therefore, when the fifth control signal YSCL is output, the data at the positions corresponding to the scan electrodes Y1 to Y5 of the shift register circuit 301 are 1, 0, 2, 1, and 2.

This data is taken into the latch circuit 301 in synchronization with the control signal LP. Therefore, the data at the positions corresponding to the scan electrodes Y1 to Y5 of the shift register circuit 301 are also 1, 0, 2, 1, and 2 data. Accordingly, the voltage output from the switch circuit 303 is applied to the scan electrode Y1 by V
Vs, ie, Vs2, sig / 2, Y2, −Vsig / 2, Y4, Y3
+ Vsig / 2 and -Vsig / 2 at Y5, and this voltage is output during the period t2.

Similarly, by repeating the operation of appropriately setting the data of the control signals Sy1 and Sy0 and writing the data to the Y driver, the waveform of the unipolar charge / discharge drive of the 1H write drive shown in FIG. 4 can be created. This drive can be performed.

Here, only the case of the unipolar charge / discharge drive waveform of the 1H write drive shown in FIG. 4 has been described, but the case of the unipolar charge / discharge drive waveform of the 0.5H write drive shown in FIG. 5 will be described. Is the control signal Sy1, twice in one selection period.
By appropriately setting the data of Sy0 and writing the data to the Y driver, a drive waveform can be created in the same manner as the 1H write drive. FIG. 8 is a diagram showing the timing when performing the 0.5H write drive. Although a detailed description of this diagram is omitted, the drive waveform of FIG. 5 can be obtained by giving control signals Sy1, Sy0, LP, YSCL and Ss as shown in the diagram. Further, the drive waveforms of FIG. 6 and other drive waveforms are also controlled by control signals Sy1, Sy0.
It can be easily realized by repeating the operation of appropriately setting the above data and writing the data to the Y driver.

As described above, paying attention to the fact that Vs1 and Vs2 are not simultaneously output, one of Vs1 and Vs2 is determined in advance.
By providing a circuit for selecting and outputting one of them, the switch configuration of the Y driver can be changed to a four-input one-output configuration in a unipolar charge / discharge driving method requiring five output voltages, and the configuration of the Y driver is simplified. It is possible to reduce the cost of the Y driver and reduce the size of the external shape, and thereby reduce the cost of the liquid crystal device and reduce the size of the external shape.

4 to 8, the voltages Vs1, Vs2, Vs
Although the case where pre and Vsig are positive voltages is shown as an example, it goes without saying that the voltages Vs1, Vs2, Vpre, and Vsig may be negative voltages.

Further, the configuration of the Y driver is not limited to the configuration of the present embodiment, and any configuration may be used as long as the configuration of the output switch can perform the above operation with four inputs and one output.

[Embodiment 2] The present invention relates to the second aspect of the present invention. Before describing this embodiment in detail, the driving waveforms of bipolar charge / discharge driving and the basic concept of this embodiment will be described. Will be described.

FIG. 9 is a diagram showing an example of a driving waveform in the bipolar charge / discharge driving method. The symbols and the like are the same as those in FIG. 4, in one frame and two frames, mode 1 in which the voltage Vs1 is the first selection voltage, voltage −Vpre is the first precharge voltage, and voltage Vs2 is the second selection voltage. The selection is made in any one of the two modes. a-frame and b-frame are voltage
The selection is performed in one of the mode 3 in which Vs1 is the third selection voltage and the mode 4 in which the voltage Vpre is the second precharge voltage and the voltage -Vs2 is the fourth selection voltage.

Here, in the bipolar charge / discharge driving method, generally, one frame and two frames are repeatedly driven a plurality of times, and then the a frame and the b frame are repeatedly driven a plurality of times, and this is repeated.

Here, the repetitive driving of one frame and two frames and the repetitive driving of a frame and b frame are respectively unipolar charge / discharge driving with inverted polarities.

Therefore, as in the first embodiment, the voltages Vs1 and Vs2 are not simultaneously applied to the scanning electrodes during the repetitive driving of one frame and two frames, and the voltage Vpre is not used. During repeated driving of the frame, the voltages -Vs1 and -Vs2 are not simultaneously applied to the scan electrodes, and the voltage -Vpre is not used.

Therefore, when driving one frame and two frames repeatedly, one of the voltages Vs1 and Vs2 is applied, and when driving a frame and b frames repeatedly, the voltage Vpre is used.
Is selected and output as + Vs, and at the time of repeated driving of one frame and two frames,
The voltage -Vpre is selected by selecting one of the voltages -Vs1 and -Vs2 when the frame a and the frame b are repeatedly driven.
By providing the second switch circuit that outputs the voltage as Vs, the switch configuration of the Y driver circuit that supplies the voltage waveform to be applied to the scan electrode of the liquid crystal element is ± Vs and ± Vsi
The switch configuration can be simplified to select one of the four values of g / 2.

FIG. 10 is a diagram showing a specific configuration example of the liquid crystal device of this embodiment.
Except for 5, the same configuration and operation as in the liquid crystal device of FIG.
The same numbers are assigned and the description is omitted. 101 is a power supply circuit.
Eight voltages of ± Vpre, ± Vs1, ± Vs2, ± Vsig / 2 are output.

Reference numerals 102a and 102b denote switch circuits, respectively. 102a selects one of the voltages + Vpre, + Vs1 and + Vs2 by a plurality of control signals Ssa, and sets the voltage +
Output as Vs. Similarly, 102b is a voltage −Vpre,
A control signal group 105 for selecting one of -Vs1 and -Vs2 by a plurality of control signals Ssb and outputting it as a voltage -Vs is a control signal group 105 for controlling the switch circuits 102a and 102b, and a Y driver 13 , And control signals Sx for controlling the X driver 14.

Voltage output from power supply circuit 101 ± Vsig / 2
The voltage of ± Vs output from the switch circuits 102a and 102b is supplied to the Y driver 13, but Vs is applied to the voltage input terminal V0, voltage + Vsig / 2 and V2 are applied to the V1 terminal in the Y driver 13 in FIG. -Vsig / 2, and supply the voltage -Vs to the V3 terminal. Therefore, when the bit state of the latch circuit 302 corresponding to this switch circuit is 3, the voltage Vs,
A voltage of -2, -Vsig / 2, a voltage of 1, + Vsig / 2, and a voltage of 0, + Vs are selected and output.

The configuration is as described above.

Here, in order to obtain the drive waveform shown in FIG. 9, the voltage -Vs supplied to the Y driver 13 is first reduced to the voltage -Vpre during the repetitive driving of one frame and two frames.
And the voltage Vs is set to one of the voltages Vs1 and Vs2. That is, this is the same as the unipolar charge / discharge drive of the first embodiment, and the switch circuit 102b selects the voltage −Vpre,
The control signal Ssb is set to output. The control signal Ssa may be set so that the switching circuit 102a selects one of the voltages Vs1 and Vs2 in the same manner as in the first embodiment.

Further, during the repetitive driving of the a-frame and the b-frame, the voltage + Vs supplied to the Y driver 13 is fixed to the voltage + Vpre, and the voltage -Vs is set to one of the voltages -Vs1 and -Vs2. That is, this is also the same as the unipolar charge / discharge drive in which the polarity is inverted in the first embodiment, and the switch circuit 102 is similar to the one-frame and two-frame repetitive drive.
a selects a voltage Vpre and outputs a control signal Ssa
And the switch circuit 102b sets the voltages -Vs1 and -Vs2
The control signal Ssb may be set such that the method of selecting either one is the same as in the first embodiment.

Here, when switching between the one-frame and two-frame repetitive driving and the a-frame and the b-frame repetitive driving, it may be necessary to output, for example, the voltages + Vs1 and + Vpre at the same time. One virtual scanning electrode that does not actually exist is added (in this embodiment, Y
6) The selection period t6 to T6 for the scanning electrode may be provided in the frame. The actual number of scanning electrodes is several hundred, and adding this single virtual electrode does not affect the display quality at all.

As described above, in the bipolar charge / discharge driving method, the voltages + Vs1, + Vs2, and + Vpre and the voltages -Vs1, -V
Paying attention to the fact that Vs2 and -Vpre are not output at the same time, a circuit that selects and outputs one of the voltages Vs1, Vs2, and Vpre in advance and one of the voltages -Vs1, -Vs2, and -Vpre
By providing a circuit for selecting and outputting one of them, the switch configuration of the Y driver can be a four-input one-output configuration even in a bipolar charge / discharge driving method requiring an eight-value output voltage. It is possible to simplify, reduce the cost of the Y driver and downsize the outer shape,
As a result, the cost of the liquid crystal device and the size of the liquid crystal device can be reduced.

[Embodiment 3] The present embodiment relates to the third aspect of the present invention and relates to the configuration of a voltage output means, that is, a Y driver.

In this embodiment, the switch circuit 12 of FIG. 1 is incorporated in a Y driver 13 formed of an integrated circuit. FIG. 11 is a diagram showing an example of the configuration of the Y driver of this embodiment.

The Y driver of this embodiment is denoted by 1103, and the same configuration and operation as in FIG.
The same numbers are assigned and the description is omitted.

A switch circuit 12 operates in the same manner as the switch circuit 12 shown in FIG.

Since the above configuration and operation are performed, the same operation as the switch circuit 12 and the Y driver 13 shown in FIG. 1 can be performed.

Here, the Y driver 1103 generally has several tens to several hundreds of switch circuits 303, and even if one more switch circuit 12 is added, the scale, outer shape, and cost of the integrated circuit can be reduced. Is almost unchanged. Therefore, FIG.
When considering a liquid crystal device that performs unipolar charge / discharge driving as described above, the external switch circuit 12 becomes unnecessary, and the external shape and
Cost can be reduced.

[Embodiment 4] The present embodiment relates to the invention of claim 4, and relates to the configuration of the voltage output means, that is, the Y driver. In the fourth embodiment, the Y driver in unipolar charge / discharge driving has been described. However, the same applies to the Y driver in amphoteric charge / discharge driving.

That is, the switch circuits 102a, 1a,
02b may be incorporated in the Y driver 13 formed of an integrated circuit. FIG. 12 is a diagram showing a configuration example of another embodiment relating to the configuration of the Y driver.

In the present embodiment, the Y driver is denoted by 1203, and in the figure, except for 102a and 102b, the same configuration and the same operation are performed as in FIG.

Reference numerals 102a and 102b denote switch circuits which operate in the same manner as the switch circuits 102a and 102b shown in FIG.

Since the above configuration and operation are performed, the same operations as the switch circuits 92a and 92b and the Y driver 13 shown in FIG. 10 can be performed. Therefore, similarly to the third embodiment,
In the case of a liquid crystal device which performs bipolar charge / discharge driving as shown in FIG. 10, the external shape and cost can be reduced by eliminating the need for the external switch circuits 102a and 102b.

[Embodiment 5] This embodiment is directed to claim 5, but before describing the liquid crystal device of this embodiment in detail, the basic concept of this embodiment will be described.

In the first embodiment, the unipolar charge / discharge driving method requiring five voltage values has been shown to be able to be driven by a four-valued Y driver. However, the voltage range output by the Y driver is Vs1 + Vpre. Therefore, the withstand voltage of the integrated circuit constituting the Y driver is higher than this voltage, and the characteristics of the nonlinear resistance element and the liquid crystal in the liquid crystal element are different. For example, when the MIM element is used as the nonlinear resistance element, it is necessary. Voltage may be around Vs1 = 20V and around Vpre = 30V, and the withstand voltage required for the Y driver is 50-60.
In some cases, the voltage may reach about V, and an extremely high withstand voltage is required.

Here, from the voltage waveform of the 0.5H write driving method shown in FIG. 5, it can be seen that the scan electrodes Vs1, Vs2 and -Vpre are not output at the same time.

In general, without being limited to this driving, in the 2 selection period, that is, in the 2H period, when the time at the beginning of this period is set to 0, the time for applying Vs1 is ta1 to ta2, and -Vpre is applied. The time is tb1 to tb2, and the time when Vs2 is applied is tc1.
Tc2, where ta1> 0 or = 0, ta2 <tb1 or ta2 = tb1, tb2 <tc1 or tb2 = tc1, tc2 <2H
Alternatively, in the charge / discharge driving method in which the time for applying each voltage is set so as to satisfy the relationship of tc2 = 2H, the voltages Vs1, Vs2, and -Vpre are not simultaneously applied to the scan electrodes.

The present invention focuses on this, and the voltage Vpr
If e is assumed to be a positive voltage, when a switch circuit having a Y driver outputs a voltage −Vpre, the highest voltage output by another switch circuit is Vsig / 2. here,
Vpre + Vsig / 2 is defined as voltage VDDH. Next, when one switch circuit of the Y driver outputs the voltage Vs1, the highest voltage output by the other switch circuits is lower than the voltage Vs1, and the lowest voltage is higher than Vs1−VDDH.

Similarly, when a switch circuit having a Y driver outputs a voltage Vs2, the highest voltage output from another switch circuit is lower than the voltage Vs2, and the lowest voltage is Vs2.
higher than s2-VDDH.

Therefore, the power supply voltage required to drive the Y driver is VDDH, and the voltage at the upper end of this power supply voltage is changed to the voltages Vsig / 2, Vs1, and Vs2 as necessary, and the drive is performed. −Vpre, Vs1, Vs2 can be output, and the withstand voltage of the Y driver is VDDH, ie,
Vpre + Vsig / 2. Here, since Vsig is generally about 2 to 6 V, the breakdown voltage of the Y driver can be reduced to less than 40 V in the case where the MIM element is used as the above-described nonlinear resistance element.

Here, a specific configuration example of this embodiment will be described with reference to the drawings.

FIG. 13 is a diagram showing a specific configuration example of the present embodiment. In the figure, the parts other than 131 and 135 operate in the same manner as in FIG.

131 is a power supply circuit, 135 is a control signal group,
136 is an isolation circuit.

Here, the ground voltage GNDY of the Y driver 13 is not common with the ground voltage of the power supply circuit 131.

FIG. 14 is a diagram showing a detailed configuration example of the power supply circuit 131.

Referring to FIG. 14, reference numeral 1401 denotes the X driver 14 shown in FIG.
The power source is a single power source in this figure, but a plurality of power sources depending on the configuration of the X driver 14 in FIG. Reference numerals 1402a to 1402g denote voltage sources, each of which has a voltage of -Vsig / 2, + Vsig / 2, + Vs2, + Vsig / 2.
Vs1, -Vpre, Vs2-VDDH, and Vs1-VDDH are generated. Here, the value of VDDH is Vsig / 2 + Vpre.

Reference numerals 1403a and 1403b are linked switch circuits for switching and outputting the voltages of the voltage sources 1402b to 1402g in accordance with the numerical values represented by the two bits of the control signals Sv1 and Sv0. That is, when the numerical value represented by the two bits of the control signals Sv1 and Sv0 is 0, 1, and 2, the switch circuit 140
3a outputs Vs1, Vs2, and Vsig / 2 as a voltage VDDHY, respectively, and the switch circuit 1403b outputs Vs1-VDDH, Vs2-VDDH, and -Vpre as a voltage GNDY, respectively. Therefore, the voltage between the voltage VDDHY and GNDY is always VDDH.

Reference numeral 1404 denotes a power supply regulator which operates at a voltage VDD.
This circuit generates a constant voltage of 3 to 5 V based on the voltage of HY to GNDY.

The voltage VDDHY output from the power supply circuit is supplied to the terminals VDDHY and V0 of the Y driver 13, and the voltage G
NDY is supplied to the terminals GNDY and V3 of the Y driver 13, and
sig / 2 is supplied to the V1 terminal, and -Vsig / 2 is supplied to the V2 terminal.

The configuration and operation of the power supply circuit 131 are as described above.

In FIG. 13, the control signal group 135 includes control signals Sv 1 and Sv 0 for controlling the power supply circuit 121, the Y driver 13
, And control signals Sx for controlling the X driver 14.

The isolation circuit 16 is connected to the ground voltage 1
Control signals Sy1, Sy0, YSCL, LP based on 6 (0V)
Is a circuit that converts a signal into a logical signal based on the ground voltage GNDY of the Y driver 13. In this embodiment, the circuit is configured by a so-called photo coupler that converts an electric signal into an optical signal and then converts the optical signal into a voltage. ing.

The configuration of the present embodiment is as described above.

Next, the operation of this embodiment will be described. FIG.
FIG. 4 is a diagram showing voltage waveforms of scanning electrodes and timings of control signals for explaining the operation.

The symbols in the figure are the same as those in FIG. 7, and as shown in the figure, the control signals Sv1 and Sv0 correspond to the periods t1, 3, t5 and T5.
2. t2, t2 so that the voltage VDDHY becomes Vs1 at T4.
4, so that it becomes Vs2 in the second half of each period of T1, T3, and T5, and Vsig / 2 in the first half of each period of t2, t4, T1, T3, and T5. Where t
In the first half of each period of 2, t4, T1, T3, T5, the voltage VDD
When HY becomes Vsig / 2, the voltage GNDY becomes -Vpre.

Then, before the 0.5HH period preceding the latter half of the period t1, that is, in the first half of the period t1, as shown in FIG.
It changes in the order of 2, 1, and 0 and is taken into the shift register circuit 301 of the Y driver 13 in FIG. Therefore, when the fifth control signal YSCL is output, the data at the positions corresponding to the scan electrodes Y1 to Y5 of the shift register circuit 301 are 0, 1, 2, 1, and 2.

This data is taken into the latch circuit 301 in synchronization with the control signal LP. Therefore, the data at the positions corresponding to the scan electrodes Y1 to Y5 of the shift register circuit 301 are also 0, 2, 2, 1, and 2 data. Accordingly, the voltage output from the switch circuit 303 is applied to the scan electrode Y1 by V
DDHY, that is, voltages + Vs1, + Vsig / 2 for Y2, and -Vs for Y3
ig / 2, Y4 becomes + Vsig / 2, and Y5 becomes -Vsig / 2, and this voltage is output during the 0.5H period from the latter half of the period t1.

Similarly, in the latter half period of t1, as shown in the figure, the control signals Sy1 and Sy0 are synchronized with the control signal YSCL.
2, 1, 2, 3, 1 in order, and the Y driver 1 in FIG.
3 is taken into the shift register circuit 301. Therefore, when the fifth control signal YSCL is output, the data at the positions corresponding to the scan electrodes Y1 to Y5 of the shift register circuit 301 are 1, 3, 2, 1, and 2.

This data is taken into the latch circuit 301 in synchronization with the control signal LP. Therefore, the data at the positions corresponding to the scanning electrodes Y1 to Y5 of the shift register circuit 301 are also 1, 3, 2, 1, and 2 data. Accordingly, the voltage output from the switch circuit 303 is applied to the scan electrode Y1 by V
sig / 2, GND2 at Y2, ie, -Vpre, Y3 at -Vsig / 2, Y4
+ Vsig / 2, and -Vsig / 2 at Y5, and this voltage is output for the first half of the period t2 for 0.5H.

Similarly, by repeating the operation of setting the data of the control signals Sy1 and Sy0 as appropriate and writing the data to the Y driver, the 0.5H write operation shown in FIG. 5 is performed using the Y driver having a withstand voltage of about Vpre + Vsig / 2. A driving unipolar charge / discharge driving waveform can be generated, and this driving can be performed.

As described above, in the charge / discharge driving method, there is a certain degree of freedom in setting each voltage. For example, it is set so that the voltage voltages Vs1, Vs2, and -Vpre are not simultaneously applied to the scanning electrodes of the liquid crystal element. By changing the voltage of the Y driver as a whole in such a setting, the switch configuration of the Y driver in the unipolar charge / discharge driving method requiring five output voltages as in the first embodiment is possible. Can be configured to have four inputs and one output, and the withstand voltage of the Y driver can be significantly reduced. Therefore, the configuration can be further simplified, and the cost and size of the Y driver can be further reduced. Thus, the cost of the liquid crystal device and the size of the liquid crystal device can be reduced.

Note that Vpre, Vs
1 and Vs2 are both drawn with positive values.
Re, Vs1, and Vs2 may both be negative values.

Further, in this embodiment, the case where the power supply voltage of the logic circuit of the Y driver is a positive voltage with respect to the ground voltage GNDY of the Y driver 13 is described. Is the higher voltage, voltage VDDHY, and the power supply voltage of the logic circuit may be a negative voltage. In this case, the voltage regulator 1404 in FIG. 14 may be changed to a voltage regulator that outputs a negative voltage with GNDY as an input, based on VDDHY.

[Embodiment 6] The present embodiment relates to a liquid crystal device according to claim 6, but before a detailed description of the liquid crystal device of this embodiment, the basic concept of this embodiment will be described.

As described in the second embodiment, the bipolar charge / discharge drive method includes unipolar charge / discharge drive using voltages Vs1, Vs2, and -Vpre and unipolar charge / discharge drive using voltages -Vs1, -Vs2, and Vpre. This is a combination of charge and discharge drive.

Therefore, similarly to the fifth embodiment, the drive waveform of the charge / discharge drive is appropriately set so that Vs1 and -Vpre or -Vs1 and Vpre are not simultaneously applied to the scanning electrode of the liquid crystal element, thereby obtaining the second embodiment and the like. Then, as the withstand voltage of the Y driver,
What required 2 · Vpre was replaced with Vpr in the same manner as in the fifth embodiment.
A bipolar charge / discharge drive driving method can be performed using a Y driver having a relatively low withstand voltage of about e + Vsig / 2.

FIG. 16 shows a specific configuration example of the liquid crystal device of this embodiment.

In the figure, the structure and operation are the same as those of the liquid crystal device of FIG. 13 except for 161 and 165.

161 is a power supply circuit, and 165 is a control signal group.

FIG. 17 is a diagram showing a detailed circuit configuration example of the power supply circuit 161. In the figure, 1702b to 1702g and 1
Except for 703a and 1703b, the configuration and operation are the same as the configuration of the power supply circuit 131 in FIG.

Reference numerals 1702b to 1702g denote voltage sources, -Vsig / 2, -Vs2, -Vs1, VDDH-Vsig / 2, -Vpr, respectively.
e, generate voltages of VDDH-Vs2 and VDDH-Vs1. Here, the value of VDDH is Vsig / 2 + Vpre.

Reference numerals 1703a and 1703b denote interlocking switch circuits, and voltage sources 1402b to 1402b corresponding to a numerical value represented by two bits of control signals Sv1 and Sv0 and a control signal Sv2.
2g, and switches and outputs voltages of 1702b to 1702g.

That is, the control signal Sv2 is "0" and the control signal Sv
When the numerical value represented by two bits of 1, Sv0 is 0, 1, 2, the switch circuit 1703a outputs Vs1, Vs2,
Vsig / 2 is output as a voltage VDDHY, and the switch circuit 1703b outputs Vs1-VDDH, Vs2-VDDH,
-Output Vpre as voltage GNDY. And the control signal S
When v2 is "1" and the numerical values represented by the two bits of the control signals Sv1 and Sv0 are 0, 1, and 2, the switch circuit 1703a
Are VDDH-Vs1, VDDH-Vs2, and Vpre, respectively.
Output as DHY and switch circuit 1703b
Outputs -Vs1, -Vs2, and -Vsig / 2 as a voltage GNDY.

In summary, when the control signal Sv2 is "0" and the numerical value represented by the two bits of the control signals Sv1 and Sv0 is 0, VDD
When HY = Vs1,1 VDDHY = Vs1,2 When GNDY = -Vp
When the re control signal Sv2 is "0" and the numerical value represented by the two bits of the control signals Sv1 and Sv0 is 0, GNDY = -Vs1, and 1 when GND.
When Y = -Vs1,2, VDDHY = Vpre, and the control signal Sv
By 2, the polarity is reversed.

The configuration and operation of power supply circuit 161 are as described above.

In FIG. 16, a control signal group 165 includes control signals Sv2, Sv1, Sv0 for controlling the power supply circuit 161, control signals Sy1, Sy0, YSCL, LP for controlling the Y driver 13 and a plurality of signals for controlling the X driver 14. Of the control signal Sx.

The liquid crystal device of this embodiment has the above-described configuration.

By switching the control signal Sv2 between 0 and 1 every several frames, unipolar charge / discharge driving with inverted polarity can be performed alternately.

Therefore, in the bipolar charge / discharge driving method requiring an eight-valued output voltage as in the second embodiment, the switch configuration of the Y driver can be a four-input one-output configuration, and further, as in the fifth embodiment. Since the withstand voltage of the Y driver can be significantly reduced, the structure can be further simplified, the cost of the Y driver can be further reduced, and the outer shape can be further reduced. As a result, the cost and the outer size of the liquid crystal device can be reduced. Can be planned.

As described in the second embodiment, it may be necessary to simultaneously output, for example, + Vs1 and + Vpre at the time of polarity switching.
In addition to this, it suffices to provide a selection period for this scanning electrode.

Further, in this embodiment, the case where the power supply voltage of the logic circuit of the Y driver is a positive voltage with respect to GNDY is described. When the driver is configured and the power supply voltage of the logic circuit becomes a negative voltage with respect to the highest potential VDDHY, the voltage regulator 1704 in FIG. good.

[Embodiment 7] As described above, Embodiment 1
In the liquid crystal device described in (6), since the configuration of the Y driver is simplified, the size and weight are reduced and the cost is reduced while obtaining high quality with little display unevenness by the charge / discharge driving method.

Therefore, it is most suitable as a display member of a high-quality, small, lightweight, and inexpensive electronic device. Examples include car navigation systems, portable information devices,
It is ideal for LCD TVs, multi-function calculators with graphic display functions, mobile phones, laptops and various other personal computers.

Further, it is possible to provide a product which has no display unevenness, is low in cost, is small, and is lightweight by using it for a light valve of a projection display device such as a projector in which display unevenness is easily seen. Become.

[0175]

According to the first aspect of the present invention, a unipolar charge / discharge driving method requiring a quinary voltage can be driven by a quaternary output Y driver, so that cost reduction and space saving can be achieved.

According to the second aspect of the present invention, the bipolar charge / discharge driving method that requires an eight-value voltage can be driven by a four-value output Y driver, so that cost reduction and space saving can be achieved.

According to the third aspect of the present invention, by incorporating one external switch circuit into the Y driver,
Since an external switch circuit can be eliminated, constant cost and space saving can be achieved.

According to the fourth aspect of the present invention, by incorporating two external switch circuits into the Y driver,
Since an external switch circuit can be eliminated, cost reduction and space saving can be achieved.

According to the fifth aspect of the present invention, since the unipolar charge / discharge driving method requiring a five-value voltage can be driven by a low-breakdown-voltage four-value output Y driver, further cost reduction and space saving can be achieved. .

According to the sixth aspect of the present invention, the bipolar charge / discharge driving method requiring an eight-value voltage can be driven by a low-breakdown-voltage four-value output Y driver, so that cost and space can be further reduced. .

According to the invention of claim 7, claims 1 to 7 are provided.
Since the liquid crystal device described above is mounted, an electronic device having a display portion with good display quality can be provided at a small size and at a low price.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration example of a liquid crystal device according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a configuration example of a liquid crystal element used in the liquid crystal device according to the first embodiment of the present invention.

FIG. 3 is a diagram illustrating a configuration example of a Y driver used in the liquid crystal device according to the first embodiment of the present invention.

FIG. 4 is a diagram showing an example of a voltage waveform of unipolar charge / discharge driving.

FIG. 5 is a diagram showing another example of the voltage waveform of the unipolar charge / discharge drive.

FIG. 6 is a diagram showing still another example of the voltage waveform of the unipolar charge / discharge drive.

FIG. 7 is a diagram illustrating voltage waveforms of scan electrodes and timings of control signals for explaining the operation of the liquid crystal device according to the first embodiment.

FIG. 8 is a diagram showing timing when performing 0.5H write driving.

FIG. 9 is a diagram showing an example of a driving waveform in a bipolar charge / discharge driving method.

FIG. 10 is a diagram illustrating a specific configuration example of a liquid crystal device according to a second embodiment.

FIG. 11 is a diagram illustrating a configuration example of a Y driver according to a third embodiment.

FIG. 12 is a diagram illustrating a configuration example of a Y driver according to a fourth embodiment.

FIG. 13 is a diagram showing a specific configuration example of a liquid crystal device according to a fifth embodiment.

FIG. 14 is a diagram illustrating a configuration example of a power supply circuit used in a liquid crystal device according to a fifth embodiment.

FIG. 15 is a diagram showing a voltage waveform of a scanning electrode and a timing of a control signal for explaining the operation of the liquid crystal device according to the fifth embodiment.

FIG. 16 is a diagram showing a specific configuration example of a liquid crystal device according to a sixth embodiment.

FIG. 17 is a diagram illustrating a configuration example of a power supply circuit used in a liquid crystal device according to a sixth embodiment.

FIG. 18 is a diagram showing an electric equivalent circuit of one pixel of the liquid crystal element of FIG. 2 of the related art.

FIG. 19 is a diagram showing a driving waveform of a conventional four-level driving method.

FIG. 20 is a diagram showing a driving waveform of a conventional unipolar charge / discharge drive.

FIG. 21 is a diagram showing drive waveforms of a bipolar charge / discharge drive according to the related art.

[Explanation of symbols]

 10. Liquid crystal element 11. Power supply circuit 12. Switch circuit 13. 13. Scan electrode drive circuit (Y driver) 14. Signal electrode drive circuit (X driver) Control signal group 16. Ground voltage (0V)

Claims (7)

[Claims] A plurality of scanning electrodes are formed on one of a pair of substrates sandwiching a liquid crystal layer, and a plurality of signal electrodes are formed on the other substrate so as to intersect the scanning electrodes.
A liquid crystal element in which a non-linear resistance element and a pixel electrode are formed at each intersection of the scanning electrode and the signal electrode, and a pixel is formed by the scanning electrode or the signal electrode facing the pixel electrode and the pixel electrode; A signal electrode driving means for applying a pulse width or a voltage-modulated signal voltage waveform to each of the plurality of signal electrodes; and, in a first mode, applying a first selection voltage to each of the plurality of scan electrodes. In the mode, a first precharge voltage having a polarity opposite to that of the first selection voltage is applied to the center voltage of the signal voltage waveform, and then the first precharge voltage is set with reference to the center voltage of the signal voltage waveform. In a liquid crystal device including a scan electrode driving unit that applies a second selection voltage having a polarity opposite to a charge voltage to each of the plurality of scan electrodes, the scan electrode driving unit includes the first selection voltage and the second selection voltage. A first voltage switching means for switching a selected voltage; and a voltage output from the first switching means, the first precharge voltage, and one or a plurality of non-selection voltages. A liquid crystal device comprising voltage output means for applying a voltage to a scanning electrode. 2. A liquid crystal device according to claim 1, wherein said signal electrode driving means, said first mode and said second mode, and in a third mode, a center voltage of said signal voltage waveform is adjusted. A third selection voltage having a polarity opposite to that of the first selection voltage is applied to each of the plurality of scan electrodes. In a fourth mode, the third selection voltage and the center voltage of the signal voltage waveform are applied to the third selection voltage. A scan electrode for applying a second selection voltage having a polarity opposite to that of the second precharge voltage with respect to a center voltage of the signal voltage waveform to the plurality of scan electrodes after applying a second precharge voltage having a reverse polarity. In a liquid crystal device including a driving unit, the scanning electrode driving unit switches the first selection voltage, the second selection voltage, and the second precharge voltage, the second voltage switching unit, and the third voltage switching unit. Selection voltage and the fourth selection Voltage switching means for switching the voltage and the first precharge voltage, and selecting any one of the voltage output from the second voltage switching means and the third voltage switching means and the non-selection voltage. And a voltage output means for applying a voltage to each of the plurality of scanning electrodes. 3. The liquid crystal device according to claim 1, wherein said first voltage switching means is provided on the same integrated circuit together with said voltage output means. 4. The liquid crystal device according to claim 2, wherein said second and third voltage switching means are provided on the same integrated circuit together with said voltage output means. 5. A liquid crystal device according to claim 1, wherein a power supply voltage for driving said voltage output means changes according to a change in a voltage output by said voltage switching means. 6. A liquid crystal device according to claim 2, wherein a power supply voltage for driving said voltage output means changes according to a change in a voltage output by said first or second voltage switching means. Characteristic liquid crystal device. 7. An electronic apparatus comprising the liquid crystal device according to claim 1.