JPH08278483A - Liquid crystal image display device - Google Patents

Abstract

PURPOSE: To provide a bright liquid crystal image display device with high contrast and less flicker by inverting polarities of an image signal and a stored image signal and outputting them to a signal electrode drive means at the timing alternately switching the image signal with the stored image signal. CONSTITUTION: This device is constituted of a liquid crystal display panel 2, an image signal generation means 9, a scan electrode drive means 10 and a signal electrode drive means 11 consisting of an upper part signal electrode drive means 12 and a lower part signal electrode drive means 13. Then, the image signal generation means 9 is constituted of memories basically, and is provided with a switch means, etc., and stores the image signal SV1 based on read/write control signals EV, EL from a timing pulse generation means. Further, the means 9 switches the output of the memory based on a memory switch control signal CHA, and switches the image signal SVI based on generation source switch control signals CH1 , CH2 . Further, the means 9 switches the image signal SV1 based on image signal switch control signals CH3 , CH4 to output the image signals SVU, SVL, to the signal electrode drive means 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal image display device such as a projector or television using an active matrix type liquid crystal display panel.

[0002]

2. Description of the Related Art As disclosed in Japanese Patent Publication No. 4-67192, a conventional liquid crystal image display device has a scanning electrode driving means for driving scanning electrodes, a signal electrode driving means for driving signal electrodes, and a temporary image signal. An image signal storage unit for storing and outputting is provided, and the liquid crystal display panel is configured to be AC-driven at a predetermined timing.

FIG. 9 shows a basic configuration of a conventional liquid crystal image display device. In FIG. 9, a conventional liquid crystal image display device 50 is shown.
On one glass substrate (not shown), a plurality of scan electrodes X _{1 to} X _N arranged in the row direction and a plurality of signal electrodes Y _{1 to} Y _N arranged in the column direction are formed.

In the conventional liquid crystal image display device 50, a switching transistor 54 is provided at an intersection of a matrix formed by a plurality of scan electrodes X _{1 to} X _N and a plurality of signal electrodes Y _{1 to} Y _N.
The image signal S _V is accumulated at one end of the switching transistor 54, and a capacitor 55 for applying the accumulated charge to the liquid crystal 56 through an alignment film (not shown) is formed and connected.

Further, the conventional liquid crystal image display device 50 has a plurality of scan electrodes X _{1 to} X _N based on the scan electrode control signal C _V.
Scan electrode drive means 51 for supplying scan electrode drive signals at different timings, signal electrode drive means 52 for supplying the image signal S _V to the plurality of signal electrodes Y _{1 to} Y _N based on the signal electrode control signal C _H , image An image signal storage means (not shown) for temporarily storing and outputting the signal S _V is provided.

When a scan electrode driving signal (for example, H level) is supplied from the scan electrode driving means 51 to the scan electrode X ₁ , each switching transistor 54 is ON-controlled based on the scan electrode driving signal, and the signal electrode The image signal S _V is charged to each capacitor 55 from the signal electrode driving means 52 via the signal electrodes Y _{1 to} Y _N based on the control signal C _H , and an alignment film (not shown) is provided at one end of each liquid crystal 56. Applied through.

[0007] Image signal signal voltage proportional to the signal level of S _V, even after the switching transistor 54 is controlled to be turned off, reverse polarity video signal S _V of is applied via the switching transistor 54 in the next field It is held by the capacitor 55 until it is continuously applied to the liquid crystal 56.

When the image signal S _V is supplied to the liquid crystal 56 based on the predetermined timings of the scan electrode control signal C _V and the signal electrode control signal C _H , the liquid crystal 56 is driven and the image signal S
An image corresponding to _V is displayed on a liquid crystal display panel (not shown).

[0009] the entire image, scanning electrodes X ₁ sequentially scanning the to X _N, the image signal S _V corresponding to the position signal electrodes Y ₁ ~ by changing the polarity for each field as shown in FIG. 10
When provided by Y _N , the liquid crystals arranged in a matrix are AC-driven to display an image on the liquid crystal display panel.

In the conventional liquid crystal image display device, when the scan electrode control signal C _V and the image signal S _V are not supplied, the effective value of the signal voltage held in the capacitor 55 is caused by the leak current of the liquid crystal 56. In order to prevent the image display from becoming dark due to a decrease in the image signal, a buffer register or the like is provided in the image signal storage means, and the temporarily stored image signal S _V is charged into the capacitor 55 via the switching transistor 54 again during one field. This makes the image display brighter.

The display portion corresponding to the upper halves X _{1 to} X _M of the scanning electrodes is the upper field 51 a (hereinafter referred to as A screen),
The display section corresponding to the lower halves X _{M + 1 to} X _N of the scanning electrodes is divided into two parts, a lower field 51b (hereinafter referred to as B screen).

First, it is assumed that the image signal S _V of the B screen is digitally encoded and stored in a buffer register (not shown). Supplies directly an image signal S _V to the pixel electrode A screen corresponding to the scanning electrodes X ₁ and the signal electrodes Y _1, the picture element electrode B screen corresponding to the scanning electrodes X _{M + 1} and the signal electrodes Y ₁ The image signal S _V stored at the address M _{1,1 of the} buffer register is D / A converted and supplied.

At the same time, the address M of the buffer register
_The same image signal S _V provided to the picture element electrodes of the A screen corresponding to the scan electrode X ₁ and the signal electrode Y ₁ is A / D converted and rewritten to _1,1 .

[0014] Then, while supplying directly the image signal S _V to the pixel electrode A screen corresponding to the scanning electrodes X ₁ and the signal electrodes Y _2, corresponding to the scanning electrodes X _{M + 1} and the signal electrodes Y ₂ B Address of the buffer register M _1,2 on the picture element electrode of the screen
The image signal S _V stored in is converted to digital and supplied.

At the same time, the address M of the buffer register
_{1, 2,} and rewrites the image signal S _V of the pixel electrode A screen corresponding to the scanning electrodes X ₁ and the signal electrodes Y ₂ converts A / D.

Similarly, the image signal S _V is supplied to the picture element electrodes of the A screen from the picture element electrodes of the A screen corresponding to the scan electrodes X ₁ and the signal electrodes Y ₁ to the scan electrodes X _M and the signal electrodes Y _N. Execute up to the corresponding pixel electrode on the A screen.

On the other hand, the supply of the stored image signal S _V from the buffer register to the picture element electrodes of the B screen is performed from the picture element electrodes of the B screen corresponding to the scan electrode X _{M + 1} and the signal electrode Y _1. The pixel electrodes of the B screen corresponding to X _N and the signal electrode Y _N are executed.

Image signal S _V for all picture element electrodes of A screen
After the supply of, the image signal S _V of the A screen corresponding to 1/2 field is stored in the buffer register.

Similarly, the scan electrode X _{M + 1} and the signal electrode Y ₁
The image signal S _V is directly supplied to the picture element electrode of the B screen corresponding to the pixel address of the buffer register M at the picture element electrode of the A screen corresponding to the scan electrode X ₁ and the signal electrode Y _1.
The image signal S _V stored in ₁ , ₁ is D / A converted and supplied.

At the same time, the address M of the buffer register
_1,1 , B corresponding to the scan electrode X _{M + 1} and the signal electrode Y ₁
The same image signal S _V provided to the picture element electrodes of the screen is A / D
Convert and rewrite.

Next, the image signal S _V is directly supplied to the picture element electrodes of the B screen corresponding to the scan electrode X _{M + 1} and the signal electrode Y _2, and A corresponding to the scan electrode X ₁ and the signal electrode Y _2. Address of the buffer register M _1,2 on the picture element electrode of the screen
The image signal S _V stored in is converted to digital and supplied.

At the same time, the address M of the buffer register
₁ , ₂ , A corresponding to the scan electrode X _{M + 1} and the signal electrode Y ₂
The image signal S _V of the picture element electrode on the screen is A / D converted and rewritten.

Similarly, the image signal S _V is supplied to the picture element electrodes of the B screen from the picture element electrodes of the B screen corresponding to the scan electrode X _{M + 1} and the signal electrode Y ₁ to the scan electrode X _N and the signal electrode Y. Execute up to the picture element electrode of the B screen corresponding to _N.

On the other hand, the supply of the stored image signal S _V from the buffer register to the picture element electrodes of the A screen is carried out from the picture element electrodes of the A screen corresponding to the scan electrode X ₁ and the signal electrode Y _1. The picture element electrodes on the A screen corresponding to _M and the signal electrodes Y _N are executed.

Image signal S _V for all picture element electrodes of B screen
After the supply of, the buffer register stores the image signal S _V of the B screen corresponding to ½ field.

When the image signal S _V is supplied to the A screen, the stored image signal S _V from the buffer register is supplied to the B screen, and the image signal S _V is supplied to the B screen. Is supplied with the stored image signal S _V from the buffer register on the A screen.

The polarity of the image signal S _V provided to the signal electrodes through the signal electrode driving means 52 is inverted at a frequency of 30 Hz for each field by an inverting means (not shown).

As described above, the conventional liquid crystal image display device 50 is used.
The liquid crystal 56 includes a scan electrode driving means 51 for driving the scan electrodes, a signal electrode driving means 52 for driving the signal electrodes, and an image signal storage means for temporarily storing and outputting the image signal S _V.
The decrease in the image signal level due to the leak current is compensated by the recharging of the capacitor 55 by the image signal S _V supplied from the image signal storage means, and the liquid crystal display panel is driven with an alternating current at a frequency of 30 Hz while keeping it bright. Is configured.

[0029]

In the conventional liquid crystal image display device 50, as shown in FIG. 10, the polarity of the image signal S _V is inverted every one field, and the liquid crystal 56 is driven at a low frequency 3.
Since it is driven at 0 Hz, reproduced images with different brightness are generated for each field, and there is a problem that a flicker phenomenon occurs.

The present invention has been made to solve such a problem, and an object thereof is to provide a liquid crystal image display device capable of displaying a bright image by improving flicker.

[0031]

In order to solve the above problems, a liquid crystal image display device according to the present invention includes an image signal storage means for temporarily storing and outputting an image signal in an image signal generation means, and an image signal and an image. Image signal switching means for inverting the polarity of the stored image signal from the signal storage means, alternately switching the image signal and the stored image signal, and inverting the polarities of the image signal and the stored image signal at the timing of this switching. And output to the signal electrode driving means.

Further, in the liquid crystal image display device according to the present invention, the signal electrode driving means includes an upper signal electrode driving means corresponding to the upper half of the scanning electrode and a lower signal electrode driving means corresponding to the lower half of the scanning electrode. And an image signal and a stored image signal whose polarities are inverted every ½ field are alternately supplied to the upper signal electrode drive means and the lower signal electrode drive means.

Further, in the liquid crystal image display device according to the present invention, the image signal storage means has a multi-ported storage means which individually has an input terminal for inputting the image signal and an output terminal for outputting the stored image signal. And having a capacity capable of storing an image signal corresponding to ½ of the total number of picture element electrodes.

The liquid crystal display of the liquid crystal image display device according to the present invention is characterized in that a dielectric mirror is arranged between the picture element electrode and the liquid crystal.

[0035]

In the liquid crystal image display device according to the present invention, the image signal generating means temporarily stores and outputs the image signal and the polarity of the image signal and the stored image signal from the image signal storing means is inverted. The image signal and the stored image signal are alternately switched, and at the timing of this switching, the polarities of the image signal and the stored image signal are inverted and output to the signal electrode drive means. The capacitor whose holding voltage has dropped due to the leak current can be charged again.

Further, in the liquid crystal image display device according to the present invention, the signal electrode driving means includes the upper signal electrode driving means corresponding to the upper half of the scanning electrodes and the lower signal electrode driving means corresponding to the lower half of the scanning electrodes. Since the image signal and the stored image signal whose polarity is inverted every ½ field are alternately supplied to the upper signal electrode driving means and the lower signal electrode driving means, the image signal is the same as the conventional scanning time. 2
The liquid crystal can be driven by reversing at the double frequency.

Further, in the liquid crystal image display device according to the present invention, the image signal storage means has a multi-ported storage means which individually has an input terminal for inputting an image signal and an output terminal for outputting the stored image signal. Since it has a capacity capable of storing an image signal corresponding to ½ of the total number of picture element electrodes, the polarity of the signal electrode drive signal for driving the liquid crystal is inverted in ½ field, and the conventional scanning time However, the liquid crystal can be driven by inverting the image signal at twice the frequency.

Further, in the liquid crystal display of the liquid crystal image display device according to the present invention, since the dielectric mirror is arranged between the picture element electrode and the liquid crystal, the optical reflectance can be improved.

[0039]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an overall configuration diagram of a liquid crystal image display device according to the present invention. In FIG. 1, a liquid crystal image display device 1
Is composed of a liquid crystal display panel 2, an image signal generating means 9, a scanning electrode driving means 10, a signal electrode driving means 11 including an upper signal electrode driving means 12 and a lower signal electrode driving means 13.

The liquid crystal display panel 2 has a pair of glass substrates 3A and 3B facing each other, a transparent electrode 4 arranged on the inner surface of the glass substrate 3A, and a vertical alignment film 7 between the glass substrate 3A and the glass substrate 3B. It is composed of a liquid crystal 5, which is sealed in via a film, a pixel electrode 6 arranged on the inner surface of the glass substrate 3B, a lower alignment film 7 and a dielectric mirror 8 arranged between the pixel electrodes 6.

On the inner surface of the glass substrate 3B or on the inner surface of the glass substrate 3B, for example, on a silicon substrate (not shown), a plurality of scanning electrodes in the horizontal direction and a plurality of signal electrodes in the vertical direction are formed. The patterns are formed in a matrix, and switching transistors are formed at the intersections of the scanning electrodes and the signal electrodes.

The switching transistor may be a MOS transistor formed on a silicon substrate or a TFT transistor formed on a glass substrate.

A scan electrode, a signal electrode, and a pixel electrode 6 are connected to the three terminals (for example, the gate, source, and drain of the FET) of each switching transistor, and based on the scan electrode drive signal supplied to the scan electrode. , ON / OFF control of the switching transistor is performed, and the image signals S _VU and S _VL are supplied from the signal electrode to the pixel electrode 6.

The switching transistor is a MOS transistor formed on a silicon substrate. The liquid crystal display panel 2
In the case of the reflective type, since the silicon substrate is not optically transparent, a dielectric mirror 8 made of a dielectric material is arranged between the picture element electrode 6 connected to the MOS transistor and the liquid crystal 5, and the optical Further, a liquid crystal display panel having a better reflectance is constructed.

The scan electrode driving means 10 is provided with a shift register or the like, and a plurality of scans are performed based on the control of the scan electrode control signal C _V from a timing pulse generating means (not shown) composed of, for example, an oscillator, a frequency divider or the like. The electrodes are sequentially driven at the same time intervals to control ON / OFF of the switching transistor.

The signal electrode driving means 11 comprises an upper signal electrode driving means 12 for driving the upper half of the liquid crystal display screen and a lower signal electrode driving means 13 for driving the lower half of the liquid crystal display screen. Based on the control of the upper signal electrode control signal C _HU and the lower signal electrode control signal C _HL from the timing pulse generating means, the image signals S _VU and S _VL from the image signal generating means 9 are supplied to the signal electrodes. The image signals S _VU and S _VL display the upper half and lower half of the liquid crystal display screen, respectively.

The image signal generating unit 9, constitutes a memory in the base, a switch unit or the like, read / write control signal E _U from the timing pulse generating means (not shown), the storage of the image signal S _VI based on E _L Do.

Further, the image signal generating means 9 switches the output of the memory based on the memory switching control signal C _HA , and switches the image signal based on the source switching control signals C _H1 and C _H2 .

Further, the image signal generating means 9 switches the image signal based on the image signal switching control signals C _H3 and C _H4 ,
The image signals S _VU and S _VL are provided to the signal electrode driving means 11.

FIG. 2 shows a basic configuration diagram of a main part of the liquid crystal image display device according to the present invention. In FIG. 2, the liquid crystal image display device 1 of the present invention includes an upper signal electrode driving means 1 for driving the signal electrodes Y _{1 to} Y _N corresponding to the upper halves X _{1 to} X _M of the scanning electrodes.
2. Signal electrodes Y corresponding to the lower halves X _{M + 1 to} X _N of the scanning electrodes
_{11 to} Y _NN is provided with lower signal electrode driving means 13,
Based on the upper signal electrode control signal C _HU , the upper signal electrode driving means 12 is driven to display the upper field 10a (hereinafter referred to as A screen) in the upper half of the liquid crystal display screen by the image signal S _VU and the lower signal. The lower signal electrode driving means 13 is driven based on the electrode control signal C _HL to generate the image signal S _VL.
Due to the lower field 10b of the lower half of the liquid crystal display screen
9 is different from the conventional liquid crystal image display device 50 shown in FIG. 9 in that (hereinafter, referred to as B screen) is displayed.

The liquid crystal image display device 1 is provided with the image signal generating means 9 shown in FIG. 1, and in the first 1/2 field, the A screen is displayed directly on the basis of the image signal S _V not passing through the storage means. At the same time, the screen B is displayed based on the image signal S _V temporarily stored in the storage means corresponding to the screen B.

On the other hand, after 1/2 field, the A screen is displayed based on the image signal S _V temporarily stored in the storage means corresponding to the A screen, and the B screen is displayed without the storage means. This is performed based on the signal S _V.

The liquid crystal image display device 1 halves such a series of display operations under the control of the image signal generating means 9.
The configuration is repeated for each field, and the polarities of the image signals S _VU and S _VL are inverted every ½ field.

The number of scan electrodes corresponding to the A screen and the B screen is equal when the total number of scan electrodes is even, but when the total number of scan electrodes is odd, the number of scan electrodes is changed to the A screen and the B screen. The difference in the number of corresponding scan electrodes may be one.

FIG. 3 is a block diagram of the essential parts of the image signal generating means of the liquid crystal image display device according to the present invention. In FIG. 3, the image signal generation means 9 is an image signal storage means 1.
4, image signal switching means 15 is provided.

The image signal storage means 14 is provided with upper field storage means and lower field storage means (not shown) which are basically composed of a memory, and supplies the input image signal S _VI to the image signal switching means 15 and also generates a timing pulse. read / write control signal E _U from the means, temporarily stored on the basis of E _L.

Further, the image signal storage means 14 selects the output of the upper field storage means and the lower field storage means based on the memory switching control signal C _HA from the timing pulse generation means, and temporarily stores them in the memory. The image signal S _VM is provided to the image signal switching means 15.

The image signal switching means 15 receives the image signal S _VI based on the source switching control signals C _H1 and C _H2 from the timing pulse generating means and the image signal S temporarily stored in the memory.
_Switch to _VM .

Further, the image signal switching means 15 inverts the polarities of the switched image signal S _VI and image signal S _VM , and outputs the image signal switching control signals C _H3 and C _H4 from the timing pulse generating means. Based on this, the inverted and non-inverted image signals S _VI and S _VM are switched, and the image signals S _VU and S _VL are provided to the signal electrode driving means 11.

FIG. 4 is a block diagram of the essential parts of the image signal storage means of the liquid crystal image display device according to the present invention. In FIG. 4, the image signal storage means 14 includes an A / D converter 16,
Upper field storage means 17 having a memory such as a RAM
And lower field storage means 18, D / A converter 1
9. The switch means SWA.

The A / D converter 16 performs digital code conversion on the image signal S _VI and supplies it to the upper field storage means 17 and the lower field storage means 18.

The upper field storage means 17 is a read / write
Storing signals based on the write control signal E _U, or outputs the stored signal.

The upper field storage means 17 is for reading / reading.
When the write control signal E _U is kept at H level for 1/2 field, the signal from the A / D converter 16 is stored corresponding to the A screen for 1/2 field shown in FIG. To do.

[0064] In addition, the top field memory means 17, for example, read / write control signal E _U is 1/2 L level
When the field time is continued, the stored signal is
It is provided to the make contact a of the switch means SWA corresponding to the screen A shown in FIG.

Similarly, the lower field storage means 18 is
A signal is stored based on the read / write control signal E _L , or the stored signal is output.

The lower field storage means 18 is a read / write
When the write control signal E _L continues to be at H level for 1/2 field, the signal from the A / D converter 16 is stored corresponding to the B screen for 1/2 field shown in FIG. To do.

In the lower field storage means 18, for example, when the read / write control signal E _L changes the L level to ½.
When the field time is continued, the stored signal is
It is provided to the make contact b of the switch means SWA corresponding to the screen B shown in FIG.

The read / write control signal E _U and the read / write control signal E _L change to H and L levels for each 1/2 field, and the upper field storage means 17 is operated.
However, in the case of a storage operation, the lower field storage means 18
Performs an output operation, and the upper field storage means 17
However, in the case of output operation, the lower field storage means 18
Are configured to perform a memory operation.

The switch means SWA is 1 / based on the memory switching control signal C _HA from the timing pulse generating means.
The output of the upper field storage means 17 and the lower field storage means 18 is switched every two fields and is provided to the D / A converter 19 via the common contact c.

The D / A converter 19 receives the digitally encoded image signal stored in the upper field storage means 17 and the lower field storage means 18, and is delayed by 1/2 field with respect to the image signal S _VI . The image signal S _VM is reproduced.

FIG. 5 is a block diagram of the essential parts of the image signal switching means of the liquid crystal image display device according to the present invention. In FIG. 5, the image signal switching means 15 is a switching means SW.
1, SW2, SW3, SW4, and inverting means 20, 21.

In the first 1/2 field of the first field, the switching means SW1 controls the source switching control signal C _H1 from the timing pulse generating means.
The common contact c is connected to the make contact a by controlling (for example, H level), and the image signal S _{VI is provided} to the inversion means 20 and the make contact a of the switch means SW3.

The inverting means 20 comprises, for example, an inverter, inverts the polarity of the image signal S _V , and switches the switch means SW3.
To the break contact b.

The switch means SW3 connects the common contact c to the make contact a by controlling the image signal switching control signal C _H3 (for example, H level), and outputs the image signal S _VU of (+) polarity.

On the other hand, the switch means SW2 connects the common contact c to the break contact b under the control of the source switching control signal C _H2 (for example, L level) from the timing pulse generating means, and inverts the image signal S _VM. 21, provided to the make contact a of the switch means SW4.

The inverting means 21 is provided with, for example, an inverter, inverts the polarity of the image signal S _VM , and switches the switch means SW4.
To the break contact b.

The switch means SW4 is controlled by the image signal switching control signal C _H4 (for example, H level) so that the common contact c.
Is connected to the make contact a to output the image signal S _VL of (+) polarity, for example.

In the ½ field of the ½ field after the first field, the switch means SW1 outputs the source switching control signal C from the timing pulse generating means.
By controlling _H1 (for example, L level), the common contact c is connected to the break contact b, and the image signal S _{VM is provided} to the inverting means 20 and the make contact a of the switch means SW3.

The inverting means 20 comprises, for example, an inverter, inverts the polarity of the image signal S _VM , and switches the switch means SW3.
To the break contact b.

The switch means SW3 connects the common contact c to the break contact b under the control of the image signal switching control signal C _H3 (for example, L level), and outputs the image signal S _VU of (-) polarity.

On the other hand, the switch means SW2 controls the common contact c to make contact a by controlling the source switching control signal C _H2 (for example, H level) from the timing pulse generating means.
The image signal S _VI is supplied to the inverting means 21 and the make contact a of the switch means SW4.

The inverting means 21 is provided with, for example, an inverter, inverts the polarity of the image signal S _VI , and switches the switch means SW3.
To the break contact b.

The switch means SW4 connects the common contact c to the break contact b by the control of the image signal switching control signal C _H4 (for example, L level), and outputs the image signal S _VL of (−) polarity.

Similarly, after the second field, 1/2
Image signals S _VU and S with different polarities for each field
_VL is output with the polarity changed. Image signals S _VU and S
_VL is repeatedly output at 60 Hz.

FIG. 6 shows a block diagram of another embodiment of the image signal storage means of the liquid crystal image display device according to the present invention. In FIG. 6, the image signal storage means 22 includes a switch means S.
WA is abolished and upper field storage means 17
And, instead of the lower field storage means 18, a half field storage means 23 composed of a memory such as a RAM is provided.
This is different from the image signal storage means 14 shown in FIG. 4 in that one memory stores and outputs the image signal data one by one.

First, the half-field storage means 23 stores A /
An image signal digitally encoded by the D converter 16 for redisplaying the B screen is displayed, for example, at addresses 1, 2,
Suppose that they are stored in 3, ...

The image signal stored in the address 1 of the half field storage means 23 is controlled by the data control signal CLK (for example, H level), and is a D / A converter as a redisplay signal for redisplaying the B screen. 19 provided.

The D / A converter 19 receives the output of the half-field storage means 23, reproduces the image signal for redisplaying the B screen, and outputs the image signal S _VM .

On the other hand, the image signal S _VI input first is
It is directly output as a display signal for displaying the A screen, digitally encoded by the A / D converter 16 and controlled by the data control signal CLK (for example, L level) to redisplay the A screen. It is stored as a signal at address 1 of the half-field storage means 23.

Similarly, the image signal stored at the address 2 of the half-field storage means 23 is the data control signal C.
It is controlled by LK (for example, H level) and provided to the D / A converter 19 as a redisplay signal for redisplaying the B screen.

The D / A converter 19 receives the output of the half-field storage means 23, reproduces the image signal for re-displaying the B screen, and outputs the image signal S _VM .

On the other hand, the next input image signal S _VI is A
It is directly output as a display signal for displaying a screen and digitally encoded by the A / D converter 16,
It is controlled by the data control signal CLK (for example, L level) and is stored in the address 2 of the half field storage means 23 as a redisplay signal for redisplaying the A screen.

By repeating the same series of operations from the address 3 onward, the image signal S _VI is directly displayed on the screen A and the image signal S _VM is displayed on the screen B.
Is displayed again.

In the case of redisplaying by the image signal S _{VM on the} screen A and direct display by the image signal S _{VI on the} screen B, first, in the half field storage means 23, A
The image signal digitally encoded by the D / D converter 16 for redisplaying the A screen is displayed at, for example, addresses 1, 2,
.. are stored in memory cells 3, ...

FIG. 7 shows a signal pattern diagram of the liquid crystal image display device. In FIG. 7, a signal pattern diagram of each part will be described with reference to FIGS. 4 and 5. At point (a), the basic image signal S _VI is sequentially input for each field.

At point (b), a signal pattern diagram digitally encoded by the A / D converter 16 is shown. In E _U (read / write control signal), the first one of each field
Writing control of the upper field storage means 17 is performed in the / 2 field, and reading control is performed in the subsequent 1/2 field.

With E _L (read / write control signal), writing control of the lower field storage means 18 is performed in the first ½ field of each field, and read control is performed in the latter ½ field. Done.

At point (c), 1/2 after each field
In the field, a signal pattern diagram of the output by reading the upper field storage means 17 is shown. At point (d), a signal pattern diagram of an output by reading from the lower field storage means 18 is shown in the first 1/2 field of each field.

In C _HA (memory switching control signal), the switch means SWA is connected to the break contact b side in the first ½ field of each field and connected to the make contact b side in the latter ½ field. It

At point (e), the first 1 / th of each field
The signal pattern diagram of the output by the reading of the lower field storage means 18 is shown in 2 fields, and the signal pattern diagram of the output by the reading of the upper field storage means 17 is shown in 1/2 field after each field.

At point (f), the first 1 / th of each field
An image signal S _{VM obtained} by reproducing the output of the lower field storage means 18 in two fields by the D / A converter 19
The signal pattern diagram of
In the field, a signal pattern diagram of the image signal S _{VM obtained} by reproducing the output of the upper field storage means 17 by the D / A converter 19 is shown.

With C _H1 (source switching control signal), the switch means SW1 is connected to the make contact a side in the first ½ field of each field and to the break contact b side in the latter ½ field. To be done.

With C _H2 (source switching control signal), the switch means SW2 is connected to the break contact b side in the first ½ field of each field and connected to the make contact a side in the latter ½ field. To be done.

At point (g), the first 1 / th of each field
In 2 fields, the same signal pattern diagram as the image signal S _VI of the first ½ field of point (a) is shown, and in the ½ field after each field, ½ after point (f).
The same signal pattern diagram as the image signal S _VM is shown based on the output of the read-out of the upper field storage means 17 of the field.

At point (h), the first 1 / th of each field
In 2 fields, the same signal pattern diagram as the image signal S _VM based on the output of the lower field storage means 18 of the first 1/2 field of point (f) is read, and the 1/2 field after each field. And 1 after point (a)
The same signal pattern diagram as the image signal S _VI of the / 2 field is shown.

In C _H3 (image signal switching control signal), the switch means SW3 is connected to the make contact a side in the first 1/2 field of each field and to the break contact b side in the latter 1/2 field. To be done.

In C _H4 (image signal switching control signal), the switch means SW4 is connected to the make contact a side in the first 1/2 field of each field and connected to the break contact b side in the latter 1/2 field. To be done.

At point (i), the first 1 / th of each field
2 shows the signal pattern diagram of the (+) polarity for driving the upper signal electrode 12 shown in FIG. 2, and the 1/2 signal after each field shows the upper signal electrode 12 shown in FIG.
Shows a signal pattern diagram of (-) polarity for driving

At point (j), the first 1 / th of each field
2 shows a signal pattern diagram of (−) polarity for driving the lower signal electrode 13 shown in FIG. 2, and in the 1/2 field after each field, the lower signal electrode 13 shown in FIG.
Shows a signal pattern diagram of (-) polarity for driving

FIG. 8 shows a signal pattern diagram of another embodiment of the liquid crystal image display device. In FIG. 8, a signal pattern diagram of each part will be described with reference to FIG. FIG. 8 is different from FIG. 7 in that the image signal S _V shown in FIG. 8A is stored in the storage means 23 and output one by one according to the data control signal CLK.

At points (i) and (j), a signal pattern diagram similar to the signal pattern diagram shown in FIG. 7 is obtained.

At points (i) and (j) shown in FIGS. 7 and 8, for example, the image signals S _VU and S _VL are time- _sequentially displayed on all screens of the A screen and the B screen with (+) polarity first. The image signal S _VU having the (-) polarity is output after 1/2 field after being output by the capacitor formed on the liquid crystal display panel.
Supplied on the bottom line of the screen.

When the (-) polarity image signal S _VU is supplied to the lowermost line of the A screen, the (+) polarity image signal S _VL is held in the uppermost line of the B screen.
At the boundary between the A screen and the B screen, the electric field may be disturbed by the potential difference between the image signal S _VU of (−) polarity and the image signal S _VL of (+) polarity, and the liquid crystal may be difficult to react.

In this case, white lines may be displayed on the display screen in the normally white mode liquid crystal and black lines may be displayed in the normally black mode liquid crystal, resulting in a difficult screen.

In order to make the white line or the black line displayed on the liquid crystal screen inconspicuous, the phase of the image signal switching control signal C _H4 shown in FIGS. 7 and 8 is changed to the image signal switching control signal C _H3.
On the other hand, it may be shifted by 1/2 field and the phase of the image signal S _VL at point (j) may be shifted by 1/2 field with respect to the image signal S _VU at point (i).

By shifting the phase of the image signal S _VL by 1/2 field, the image signal S _{VL at} the points (i) and (j) can be obtained.
_VU and _SVL always have different polarities.

At points (i) and (j), for example, the image signal S _VU corresponding to the A screen and the image signal S _VL corresponding to the B screen are first (+) polarity and (−) polarity in time series, respectively. Image signal S _VU of (-) polarity after 1/2 field after being held by the capacitor formed on the liquid crystal display panel.
Is supplied to the bottom line of the A screen.

When the (-) polarity image signal S _VU is supplied to the lowest line of the A screen, the (-) polarity image signal S _VL is held in the highest line of the B screen. Since the image signals S _VU and S _VL are of the same polarity, the electric field is normally applied and the liquid crystal normally reacts at the boundary between the A screen and the B screen.

As described above, when the polarities of the image signals S _VU and S _VL at points (i) and (j) are always different from each other, for example, a reflective liquid crystal image display having a high aperture ratio is displayed. The device can further improve the display quality of the image.
In addition, since the transmissive liquid crystal image display device has a low aperture ratio and a black matrix shields light between pixels, there is no particular difference in image display quality.

The present invention particularly has a negative dielectric anisotropy,
It is possible to improve the display of the liquid crystal which is vertically aligned by coating the substrate with a silane coupling agent, a chromium complex or the like.

As described above, the liquid crystal image display device 1 is configured to invert the polarities of the image signals S _VU and S _VL for each 1/2 field, and drive the liquid crystal 5 at a frequency of 60 Hz for display.

[0122]

As described above, in the liquid crystal image display device according to the present invention, the image signal generating means includes the image signal storing means for temporarily storing and outputting the image signal, and the image signal and the image signal storing means. Image signal switching means for inverting the polarity of the stored image signal, alternately switching the image signal and the stored image signal, and inverting the polarities of the image signal and the stored image signal at the timing of this switching to drive the signal electrode. It is possible to improve the brightness of the liquid crystal display because the capacitor whose holding voltage is lowered by the leak current of the liquid crystal can be charged again by outputting to the means.

Further, in the liquid crystal image display device according to the present invention, the signal electrode driving means includes the upper signal electrode driving means corresponding to the upper half of the scanning electrode and the lower signal electrode driving means corresponding to the lower half of the scanning electrode. And an image signal and a stored image signal whose polarities are inverted every 1/2 field are alternately supplied to the upper signal electrode driving means and the lower signal electrode driving means, and the image signal is generated in the same manner as the conventional scanning time. Since the liquid crystal can be driven by reversing at the double frequency, the flicker phenomenon can be improved.

Further, in the liquid crystal image display device according to the present invention, the image signal storage means has a multi-ported storage means which individually has an input terminal for inputting an image signal and an output terminal for outputting the stored image signal. And having a capacity capable of storing an image signal corresponding to ½ of the total number of pixel electrodes,
Inversion of the polarity of the signal electrode drive signal that drives the liquid crystal is 1/2
It is done in the field, and although it is the same as the conventional scanning time,
Since the liquid crystal can be driven by inverting the image signal at twice the frequency, the flicker phenomenon can be improved with a simple configuration.

Further, in the liquid crystal display of the liquid crystal image display device according to the present invention, since the dielectric mirror can be arranged between the picture element electrode and the liquid crystal to improve the optical reflectance, the liquid crystal display can be improved. The brightness of can be improved.

Therefore, it is possible to provide a liquid crystal image display device which is bright, has high contrast, and has little flicker.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a liquid crystal image display device according to the present invention.

FIG. 2 is a basic configuration diagram of a main part of a liquid crystal image display device according to the present invention.

FIG. 3 is a block diagram of a main part of an image signal generating means of a liquid crystal image display device according to the present invention.

FIG. 4 is a block diagram of the essential parts of the image signal storage means of the liquid crystal image display device according to the present invention.

FIG. 5 is a block diagram of the essential parts of the image signal switching means of the liquid crystal image display device according to the present invention.

FIG. 6 is a block diagram of another embodiment of the image signal storage means of the liquid crystal image display device according to the present invention.

FIG. 7 is a signal pattern diagram of the liquid crystal image display device according to the present invention.

FIG. 8 is a signal pattern diagram of another embodiment of the liquid crystal image display device according to the present invention.

FIG. 9 is a basic configuration diagram of a conventional liquid crystal image display device.

FIG. 10 is an image signal pattern diagram of a conventional liquid crystal image display device.

[Explanation of symbols]

1 ... Liquid crystal image display device, 2 ... Liquid crystal display panel, 3A, 3
B ... Glass substrate, 4 ... Transparent electrode, 5 ... Liquid crystal, 6 ... Picture element electrode, 7 ... Alignment film, 8 ... Dielectric mirror, 9 ... Image signal generating means, 10 ... Scan electrode driving means, 11 ... Signal electrode driving Means, 12 ... Upper signal electrode driving means, 13 ... Lower signal electrode driving means, 14, 22 ... Image signal storage means, 15 ... Image signal switching means, 16 ... A / D converter, 17 ... Upper field storage means, 18 ... Lower field storage means, 19 ...
D / A converter, 20, 21 ... Inversion means, 23 ... Half field storage means, 5a ... Switching transistor, 5b
... condenser, 10a ... upper field, 10b ... lower field, SWA, SW1, SW2, SW3, SW4
... switch means, X _{1 to} X _N ... scan electrodes, Y _{1 to} Y _N , Y ₁₁
To Y _NN ... signal _{electrodes, S VI, S VM, S} VU, S VL ... image signals, C _HU ... upper electrode control signal, C _HL ... lower electrode control signal, E _U, E _L ... read / write control signal, _CHA ... Memory switching control signal, _CH1 , _CH2 ... Source switching control signal,
C _H3 , C _H4 ... Image signal switching control signal, a ... Make contact,
b ... Break contact, c ... Common contact.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masato Furuya, 3-12 Moriya-cho, Kanagawa-ku, Yokohama, Kanagawa, Japan Victor Company of Japan, Ltd. (72) Hiroyuki Bonde, 3-Moriya-cho, Kanagawa-ku, Yokohama, Kanagawa Address 12 Victor Company of Japan, Ltd.

Claims (4)

[Claims] 1. A liquid crystal enclosed between a pair of opposed substrates, a plurality of scanning electrodes arranged on the surface of one of the substrates and arranged in a row direction, and a plurality of signal electrodes arranged in a column direction, Switching elements connected to respective intersections of the matrix formed by the scanning electrodes and the signal electrodes,
A liquid crystal display panel including a pixel electrode connected to each of the switching elements and a scanning electrode driving unit for driving the scanning electrode, a signal electrode driving unit for supplying an image signal to the signal electrode, the image signal In the liquid crystal image display device having image signal generating means for generating the image signal, the image signal generating means includes an image signal storing means for temporarily storing and outputting the image signal, and the image signal and the image signal storing means. Image signal switching means for inverting the polarity of the stored image signal, alternately switching the image signal and the stored image signal, and at the timing of this switching, reverse the polarity of the image signal and the stored image signal. A liquid crystal image display device, which outputs to the signal electrode driving means. 2. The signal electrode driving means comprises upper signal electrode driving means corresponding to the upper half of the scanning electrode and lower signal electrode driving means corresponding to the lower half of the scanning electrode, wherein the upper signal electrode 2. The liquid crystal image display device according to claim 1, wherein the drive means and the lower signal electrode drive means are alternately supplied with the image signal and the stored image signal whose polarities are inverted every 1/2 field. 3. The image signal storage means comprises a storage means having a multiport structure, which individually has an input terminal for inputting the image signal and an output terminal for outputting the stored image signal, and the total number of picture element electrodes. 2. The storage device has a capacity capable of storing the image signal corresponding to [1/2] of the image signal.
The liquid crystal image display device described. 4. The liquid crystal image display device according to claim 1, wherein the liquid crystal display has a dielectric mirror disposed between the picture element electrode and the liquid crystal.