JPH09105903A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device in which the readout frequency of the picture data in a display memory is lowered and whose power consumption is reduced and whose size is made small by incorporating the display memory on the substrate of a display screen. SOLUTION: In a liquid crystal display device having a first substrate 1 on which transparent electrodes 4 are formed, a second substrate 2 confronted with the first substrate 1 and on which electrodes 5 are formed and a liquid crystal layer 3 held in between the both substrates, a memory area 9 storing the picture data of a display picture is formed on the second substrate 2 and a display area is formed like covering the memory area 9 and moreover the device has plural layers of insulating layers 6, 8 held in between the memory area 9 and the display area and an equipotential layer 7 held in between the insulating layers 6, 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly to a thin and lightweight liquid crystal display device which is optimal for a small portable device.

[0002]

2. Description of the Related Art Conventionally, a personal computer is shifting from a desktop type used on a desk to a notebook type with more emphasis placed on portability. In particular, liquid crystal display devices such as notebook personal computers are required to be lighter and have lower power consumption.

When displaying an image on such a liquid crystal display device, the display memory built in the personal computer main body is accessed in full time to read the stored image data, and the display controller rearranges the image data for display. The display was transmitted to the driver circuit of the liquid crystal display device.

[0004]

However, although many of the images displayed on the liquid crystal display device of the personal computer change so frequently, the liquid crystal display device side does not have a memory property. Rewriting is performed in full time at a cycle of 70 Hz. At this time, the CPU (central processing unit) of the personal computer is a RAM
The image data in the display memory configured by (Random Access Memory) is constantly read.

The frequency of reading the image data in the memory is rewritten, for example, at 60 Hz, when one scanning line is selected to be 1/240, and the number of pixels on one scanning line is 640. It reaches up to 0.2MHz. In this way, the read frequency of the memory becomes very high,
A lot of power is consumed for the reading.

Writing in a liquid crystal display device is
Generally, the line sequential scanning method is used. In the line-sequential scanning method,
The image of one entire line (scan line) is simultaneously written by one writing. As a result, when the image data is read from the display memory, the read frequency becomes the lowest when the data of all the rows are read at a time, and the power consumption related to the memory read becomes the minimum.

In a conventional personal computer, the above-mentioned display memory is installed on the main body side containing a CPU, a power source, etc., and image data read from the display memory is transferred to a liquid crystal display device via wiring. It was sent.
In this case, in order to send the image data for one row read from the display memory to the liquid crystal display device at the same time, wiring for the number of pixels in one row is required. Therefore, in the example above, 640
Book wiring is required.

It is not easy to mount such a large number of wirings in an actual device. Therefore, it is necessary to install the display memory adjacent to the liquid crystal display device side. At this time, it is considered that the display memory is made to coexist in the drive circuit IC chip on the signal side of the liquid crystal display device, but a RAM having a large capacity is required for the display memory, the chip size is enlarged, and the display surface of the liquid crystal display device is increased. The frame portion becomes large, and its portability is alienated especially in a notebook personal computer or the like.

An object of the present invention is to provide a liquid crystal display device having low power consumption and a large ratio of the effective display area of the liquid crystal display device.

[0010]

The gist of the present invention to achieve the above object is as follows.

A first substrate on which a transparent electrode is formed;
A liquid crystal display device having a second substrate facing the other substrate and having electrodes formed thereon, and a liquid crystal layer sandwiched between the two substrates, a memory region for storing image data of a display image on the second substrate. A display region is formed so as to cover the memory region, and a plurality of insulating layers sandwiched between the memory region and the display region and an equipotential layer sandwiched between the insulating layers are formed. Characteristic liquid crystal display device.

The equipotential layer sandwiched between the insulating layers is a metal layer such as aluminum (Al) or chromium (C).
r), copper (Cu), silver (Ag), gold (Au), or the like.

The memory area for storing the image data is divided into blocks for each display column. The above memory area is a RAM or a ROM (Read Only Memory).
y) and RAM, and the ROM stores fixed-form image data.

Furthermore, a central processing element may be formed on the second substrate.

It is preferable that the first substrate of the liquid crystal display device is a transparent substrate and the second substrate is made of single crystal silicon.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION RAM or R serving as a display memory
AM and ROM are formed on one substrate surface of the liquid crystal display device,
A drive circuit is formed adjacent to the display memory. And
Each display electrode is formed so as to cover these display memory and drive circuit, and this is connected to the drive circuit.

Due to the above, the outside of the effective display area (frame portion)
Therefore, it is possible to obtain a liquid crystal display device having a large ratio of effective display area to the entire area of the liquid crystal display device. Further, when the effective display areas are the same, the overall size of the liquid crystal display device can be reduced.

Since the display memory is provided on the surface of the substrate, it and the signal electrode provided on the upper surface of the substrate form a coupling capacitance, which may cause unexpected modification of the image data stored in the display memory. The phenomenon that image data cannot be read occurs. In order to prevent this, the equipotential layer is provided. The equipotential layer blocks the electric field between the signal electrode and the display memory, and an unnecessary electric field based on the coupling capacitance is not applied to the display memory.

[0019]

The present invention will now be described in more detail based on the embodiments of the present invention.

[Embodiment 1] FIG. 1 is a schematic configuration diagram of a liquid crystal display device according to the present embodiment.

A liquid crystal layer 3 is sandwiched between a first substrate 1 and a second substrate 2 which faces the first substrate 1. First substrate 1
A plurality of stripe-shaped transparent scanning electrodes 4 are formed on the substrate. On the second substrate 2, a plurality of stripe-shaped signal electrodes 5 orthogonal to the scanning electrodes 4 are formed.
The intersection of the scanning electrode 4 and the signal electrode 5 becomes a display pixel.

Although FIG. 1 shows an example of a matrix display of 4 rows × 8 columns, in a liquid crystal display device of an actual personal computer, a very large matrix such as 480 × 640 (rows × columns) is formed.

A metal layer (equipotential layer) 7 sandwiched between the first insulating layer 6 and the second insulating layer 8 is provided between the signal electrode 5 and the second substrate 2. .

A display memory 9 for storing screen information on the surface of the second substrate 2 and a signal side drive circuit 10 for supplying a signal voltage to the signal electrodes 5 according to image data in the display memory 9.
Are formed. The signal side drive circuit 10 and the signal electrode 5 are connected by a contact 11. Further, a signal side interface 12 for supplying voltage and data transfer is connected to the extension of the signal side drive circuit 10.

On the other hand, a scanning electrode 4 is formed on the first substrate 1 side, and a scanning side driving circuit 13 on which a driving circuit chip 14 for supplying a scanning signal voltage is mounted is connected.

A clock signal, a drive voltage, image data and the like are sent from the controller 15 to the signal side interface 12 and the scanning side drive circuit 13.

To apply the signal voltage to the signal electrode 5, the image data in the display memory 9 is read, the image data is converted into the signal voltage by the signal side drive circuit 10, and the signal voltage is applied to the signal electrode 5 via the contact 11. To be done.

The first substrate 1 on the observer side is made of a transparent material, and a thin plate or film of glass plate, polycarbonate, acrylic resin or the like is used, and the thickness of the substrate is 0.1.
About 5 mm.

The second substrate 2 may be transparent or opaque, and a single crystal silicon substrate, alkali-free glass or the like is used. In particular, when a single crystal silicon substrate is used, the display memory 9, the signal side drive circuit 10 or the signal side interface 12 can be directly formed on the single crystal silicon substrate using a semiconductor process. Further, the controller 15 can also be made by using a semiconductor process in the same manner, and by doing so, space saving can be further improved.

When non-alkali glass is used, the display memory 9, the signal drive circuit 10 and the signal interface 12 can be directly formed on the substrate by using a p-SiTFT (Thin Film Transistor) process. Further, it is possible to make the controller 15 similarly by using a p-SiTFT process to save space.

Scan electrode 4 formed on first substrate 1
Is an oxide of indium and tin (IntimTin Oxide)
Alternatively, a transparent and electrically conductive material such as tin oxide is used.

The signal electrode 5 is a thin film of aluminum (Al), chromium (Cr), copper (Cu), silver (Ag), gold (Au) or the like, and is formed in a stripe shape orthogonal to the scanning electrode 4. These also serve as electrodes and reflection films for incident light. Alternatively, the scanning electrode 4 may be a transparent electrode, and a reflection layer for incident light may be formed below the electrode. As the reflective layer, a white diffuser plate made of calcium oxide, titanium oxide, or the like, or a coloring layer colored with a specific color such as paint is used.

The two insulating layers 6 and 8 are made of silicon oxide (S
iO ₂ ), silicon nitride (SiN), tantalum oxide (T
(iO) or the like, an inorganic thin film, an organic film such as polyimide, an acrylic resin, or a tetrafluoroethylene resin, or a laminated film thereof.

The surfaces of the display memory 9 composed of a thin film circuit and the signal side drive circuit 10 have fine irregularities. Similarly, the surface of the signal electrode 5 also has fine irregularities, and the irregularities cause the reflected light to become scattered light, thereby improving the visibility as a display device. When it is desired to control the reflected light in a specific direction regardless of the unevenness, it is effective to smooth the uneven surface to form an uneven pattern having a specific shape.

In order to smooth the irregularities on the second substrate 2, the insulating layers 6 and 8 are formed of an organic smoothing film of polyimide, acrylic resin or the like having a thickness of 0.1 to 5 μm.

In particular, in order to avoid the influence of leakage current,
An inorganic film is used for the insulating layer 8 between the display memory 9, the signal side drive circuit 10 and the metal layer (equipotential layer) 7, and an organic film is formed on the display memory 9 and the signal side drive circuit 10 by covering them. Good.

As the liquid crystal layer 3, a guest-host type liquid crystal mode in which a dichroic dye and a liquid crystal material used in a normal liquid crystal display device are combined, and a liquid crystal material containing a dichroic dye is dispersed in a polymer film. Depending on the purpose, a known guest-host type polymer dispersed liquid crystal mode, or a TN type or STN type nematic liquid crystal mode in which a polarizing plate is arranged on the first substrate 1 on the observation side and twisted and aligned is used. Used.

Next, the state in which the display of the present embodiment is performed will be described. In the display state, a voltage of several volts to 60 volts is applied to the signal electrode 5 for driving the liquid crystal.

On the other hand, the display memory 9 stores the image data while being charged to its capacity. Since the insulating layer is formed between the signal electrode 5 and the display memory 9, a coupling capacitance is formed between the signal electrode 5 and the display memory 9. When a voltage is applied to the signal electrode 5,
Due to this coupling capacitance, an unexpected electric field is applied to the display memory 9 and electric charges are accumulated, and as a result, unexpected modification of data may occur in the display memory 9 or reading may become impossible.

To prevent this, two insulating layers 6 and 8 are provided and an equipotential layer is formed between them. This equipotential layer blocks the electric field generated between the signal electrode and the display memory,
Prevent unnecessary voltage from being applied to the display memory. In this example, the metal layer 7 made of an aluminum (Al) thin film was formed as the equipotential layer.

The display memory 9 is divided into blocks for each column of the signal electrodes 5. The data of the corresponding address of the display memory 9 is read, converted into a signal voltage for driving the liquid crystal by using the signal side drive circuit 10, and the voltage is applied to the liquid crystal layer 3 by the signal electrode 5 via the contact 11. This state will be described with reference to FIG.

As described above, the scanning electrodes 4 and the signal electrodes 5 are orthogonal to each other, and the intersections thereof form display pixels. In terms of an electric circuit, the liquid crystal layer 3 of the pixel portion is shown as a capacitance in FIG. A scan side drive circuit 13 is connected to the scan electrodes 4. An integrated circuit (IC) for applying a scanning signal voltage to the scanning electrodes 5 is formed on the tape TAB on the scanning side drive circuit 13.
It is implemented by the (Tape Autmotive Bonding) method. The IC and the scanning side drive circuit 13 are connected to each other by thermocompression bonding using an anisotropic conductive tape.

A method of directly mounting the IC chip on the substrate can also be used, and furthermore, the IC chip mounted on the printed circuit board can be connected by the anisotropic conductive tape.

A case where image data is written from the controller 15 to the display memory 9 will be described by taking a display device having a matrix of display pixels of 4 rows × 8 columns as an example.

In FIG. 2, the address (m) in the row direction is 0, 1, 2, 3 and the address (n) in the column direction is 0,
1, 2, 3, ..., 7 As an operation for writing the image data in the display memory 9, the writing is started from the address (0, 0), and first, the data is written to the address (0, 7) while the address is shifted in the column direction. When the writing of the data of the first line (m = 0) is completed, the process moves to the writing of the second line (m = 1). These addresses are
This corresponds to the arrangement of pixels on the display surface. In this way,
Data is sequentially written up to the last address (3, 7).

When displaying, the data in the display memory 9 is read and a voltage is applied to the signal electrode 5 via the signal side drive circuit 10. The display memory at the time of writing is (0,
A total of one memory space is formed from addresses 0) to (3, 7), but at the time of reading, it is treated as an aggregate of a plurality of memories that are blocked for each column (n).

The liquid crystal display device as described above employs the line-sequential scanning method, but when the image data in the display memory is read out, the data in the same row (m) are read out at the same time. In FIG. 2, when the signal side drive circuit 10 reads out the contents of the display memory in the row m = 0, converts it into a drive voltage and applies it to the signal electrode 5, at the same time, the scan side drive circuit 13 causes the scan electrode 4 on the 0th column to move. The selection voltage is applied to the pixels. As described above, writing is performed on all the pixels of the scan electrode 4 in the 0th column.

Next, m = 1 row of data is read and m =
Writing is performed on pixels in one row, and the pixels sequentially move to the next row.

As a result, when the frame frequency for rewriting is 70 Hz in the liquid crystal display device having the display capability of 640 × 480 pixels, the read frequency is 33.6 kHz.

On the other hand, in the conventional one having the display memory on the personal computer main body side, the reading frequency is 21.
5 MHz. Therefore, in the case of the present embodiment, the reading frequency is lowered by about three digits, and the power consumption is about 1/10.
It will be about 00.

Since the display memory 9 is provided on the substrate surface of the liquid crystal display device, the peripheral (frame) portion of the effective display area is
Only by disposing the contact 11 connected to the scanning side drive circuit 13 and the signal electrode 5, the frame portion can be remarkably reduced, and a small liquid crystal display device with low power consumption can be provided.

[Embodiment 2] FIG. 3 is a schematic configuration diagram of a liquid crystal display device in which two sets of signal side drive circuits are formed and a defect due to circuit redundancy is improved.

A liquid crystal layer 3 is sandwiched between a first substrate 1 and a second substrate 2 facing the first substrate 1, and a plurality of stripe-shaped transparent scanning electrodes 4 are formed on the first substrate 1. There is. A plurality of stripe-shaped signal electrodes 5 orthogonal to the scanning electrodes 4 are formed on the second substrate 2, and the intersections of the scanning electrodes 4 and the signal electrodes 5 become display pixels. The structure of the matrix is the same as in FIG. Further, a metal layer 7 sandwiched between the first insulating layer 6 and the second insulating layer 8 is formed between the signal electrode 5 and the second substrate 2.

A data bus 16 for sending out the image data read out from the display memory 9 is formed adjacent to the display memory 9, and a first signal side drive circuit 17 is provided at one end of the data bus 16 to output the image data. First converted to signal voltage
Via the contact 18 to the signal electrode 5.

A second end is provided at the other end of the data bus 16.
Signal side drive circuit 19 of the first signal side drive circuit 1
Similar to 7, the image data is converted into a signal voltage. The signal voltage obtained by the second signal side drive circuit 19 is applied from the other end side of the signal electrode 5 via the second contact 20.

Image data is sent from the controller 15 to the display memory 9 via the signal side interface 12. A scanning side driving circuit 13 having a driving circuit chip 14 mounted thereon is attached to one end of the scanning electrode 4.

The characteristics of this embodiment will be described with reference to FIG.
The image data stored in the display memory 9 is the first embodiment.
Is the same as

The display memory 9 corresponding to each column (n) of the signal electrodes 5 is provided with a data bus 16 for temporarily holding the read image data. The image data read out for each column is sent to the data bus 16. Both ends of the data bus 16 are connected to signal side drive circuits 17 and 19, respectively, and a signal voltage is simultaneously applied to each signal electrode 5 from both ends. Therefore, the capability of supplying voltage to each electrode is increased, and it is possible to prevent deterioration of image quality due to insufficient voltage supply.

Further, the liquid crystal display device of this embodiment can easily cope with a defect. As shown in FIG. 5, it is assumed that the disconnection defect 40 occurs between the m = 2nd row and the M = 3rd row of the n = 2th column signal electrode. For image display, the scanning signal voltage is sequentially applied to the scanning electrodes 4 from the 0th row by the scanning side drive circuit 13. Data is read from the display memory 9 in synchronization with this scanning signal voltage and sent to the data bus 16, converted into a signal voltage by the two signal side drive circuits 17 and 19, and a voltage is applied from the signal electrode 5 to the liquid crystal layer 3. It

At this time, in the case of only the first signal side drive circuit 17, since there is no defect in the signal electrode up to the m = 2th row, the signal voltage is supplied and normal writing is possible.
However, due to the disconnection defect 40, the signal voltage cannot be supplied to the M = th third row and below, and the pixels below the disconnection defect 40 are defectively displayed.

In this embodiment, the second signal side drive circuit 19
Since the signal voltage based on the same data can be supplied from the other end of the signal electrode 5 by the above, it is possible to display other than the disconnection defect 40 portion without any problem.

As described above, according to this embodiment, even if a disconnection defect or the like occurs, the defect can be repaired by the self-circuit, so that the inspection of the liquid crystal display device can be simplified.

[Embodiment 3] FIG. 6 is a schematic diagram of a liquid crystal display device according to this embodiment.

A liquid crystal layer 3 is sandwiched between a first substrate 1 and a second substrate 2 which faces the first substrate 1, and a plurality of stripe-shaped transparent scanning electrodes 4 are formed on the substrate 1. A plurality of stripe-shaped signal electrodes 5 that are orthogonal to the scanning electrodes 4 are formed on the substrate 2, and the intersections thereof are display pixels.
The matrix is x8 (rows x columns).

A metal layer 7 sandwiched between a first insulating layer 6 and a second insulating layer 8 is formed between the signal electrode 5 and the substrate 2. A display memory 9 for storing screen information on the substrate 2
And a signal side drive circuit 10 which converts the signal voltage into a signal voltage using the image data in the display memory 9 and supplies the signal voltage to the signal electrode 5, and is electrically connected to the signal electrode 5 by a first contact 18. .

Voltage is supplied on the extension of the signal side drive circuit 10,
A signal side interface 12 for data transfer is connected. A scan side drive circuit 13 on which a drive circuit chip 14 that supplies a scan signal voltage is mounted is connected to the scan electrodes 4. A clock signal, voltage, image data, etc. are sent from the controller 15 to the signal side interface 12 and the scanning side drive circuit 13.

In order to apply a signal voltage to the signal electrode 5, the image data in the display memory 9 is read out, the signal side drive circuit 10 converts the image data into a signal voltage, and the first
Is applied to the signal electrode 5 via the contact 18. At this time, the signal voltage generated by the signal side drive circuit 10 is applied from the opposite end of the signal electrode 5 through the signal bus line 21 and the second contact 20.

The signal bus line 21 is formed on the second substrate 2 by a thin film of aluminum (silver, gold, platinum, copper, chromium, etc.) which is a low resistance material. Also, the second
The contact 20 is also formed in the same manner as the first contact 18.

According to the above, unlike the second embodiment, since there are not two sets of signal side drive circuits (17, 19), there is no concern about variations in the characteristics of the two signal side drive circuits.

[Embodiment 4] FIG. 7 is an explanatory view of another defect correction of the liquid crystal display device of the present invention, and is a schematic plan view of the liquid crystal display device as seen from the first substrate 1 side. The edge portion of the first substrate 1 is shown by a broken line, and the edge portion of the second substrate 2 is shown by a solid line.

A signal voltage obtained by converting the image data in the display memory 9 by the first signal side drive circuit 17 is applied to the signal electrode 5 through the contact 11. Also,
The image data is sent to the second signal side drive circuit 19 through the data bus 16. A first pad 22 is formed on the end of the signal electrode 5, and a second pad 23 is formed on the output side of the second signal side drive circuit 19. These pads 22 and 23 are thin films of ITO (thin films of indium oxide, chromium, gold, platinum, copper, etc. are also possible) at the end portions on the second substrate 2 which are not covered with the first substrate 1. Is formed by.

Now, the disconnection defect 4 is present on a certain signal electrode 5 '.
The case where there is 0 will be described. In the first signal side drive circuit 17, the signal voltage can be applied only to the lower side of the disconnection defect 40. Therefore, the first pad 22 and the second pad
And the pad 23 of the same are connected by the correction contact 24. The correction contact 24 can be formed by a wire bonding method using a fine wire such as platinum or aluminum, a method of irradiating a metal such as cobalt with laser, or a method of connecting a copper wire with solder or an electrically conductive adhesive. .

In general, such a broken portion is inspected and corrected in the state of the board before the device is assembled, but a special inspection device is required for that. According to the present embodiment, since the disconnection point is corrected at the end portion of the substrate which is not covered with the substrate, it can be performed after assembling the liquid crystal display device, and no special inspection device is required and much labor is not required.

In FIG. 7, the second signal side drive circuit 1
Although 9 is formed between the second pad 23 and the data bus 16, the same effect can be obtained by forming it between the first pad 22 and the signal electrode 5.

[Embodiment 5] FIG. 8 is a schematic configuration diagram of a liquid crystal display device according to this embodiment. In this embodiment, a switching circuit for actively driving liquid crystal is formed on a substrate.

A liquid crystal layer 3 is sandwiched between a transparent first glass substrate 1 and a single crystal silicon second substrate 2. A common electrode 4 of ITO is formed on the first substrate 1.

On the second substrate 2, a first insulating layer 6, a metal layer 7 and a second insulating layer 8 are laminated. A matrix of TFTs 25 and pixel electrodes 26 is formed on the second insulating layer 8. A display memory 9 is formed below the first insulating layer 6.

The source drive circuit 2 is provided at one end of the display memory 9.
7 is formed and connected to the source wiring 29 via the source side contact 28. A gate drive circuit 30 orthogonal to the source drive circuit 27 is formed on the second substrate 2. The gate drive circuit 30 is connected to the gate wiring 32 via the gate side contact 31.

The signal side interface 12 is connected to the end of the second substrate 2 and receives a signal from the controller 15. The controller 15 is also connected to the common electrode 4 and controls the potential thereof.

The image data in the display memory 9 is read out,
The source side drive circuit 27 converts the signal voltage. The gate side drive circuit 30 formed on the same substrate generates a gate drive waveform and applies it to the gate of the TFT 25 via the gate wiring 32. The scanning method at this time is the same as in the first embodiment.
Similarly, scan every column.

The signal voltage is passed through the source line 29 and T
When a voltage is applied to the source of the FT25 and a voltage is applied to the gate, the TFT25 is turned on and the signal voltage is
In addition to the pixel electrode 26 connected to the drain side of 5,
Electric charges having the liquid crystal layer 3 as a capacitance are accumulated to drive the liquid crystal.

In the present embodiment, the gate wiring side is sequentially scanned, and the TFT 25 remains in the OFF state until a voltage is next applied to the gate of the TFT, so that the charge accumulated in the above process is retained as it is. . Note that the electric field generated between the pixel electrode 26 and the display memory 9 below it by this charge is blocked by the metal layer 7 to protect the data in the display memory 9.

In this embodiment, since the scanning side driving circuit is formed on the second substrate 2, a more compact liquid crystal display device can be realized. Further, by configuring so that the signal voltage can be applied to both ends of the source wiring 29, it is possible to easily deal with defects and the like as in the above embodiment.

Although the TFT is used as the switching element in this embodiment, it is also possible to use a switching element utilizing non-linearity in which an insulating layer is sandwiched between two layers of metal or a two-terminal element in which a diode is combined. it can.

Although the controller 15 is installed outside, it may be formed on the second substrate 2. In addition, the display memory 9
Is composed of a ROM and a RAM, data of an image to be rewritten is sequentially stored in the RAM, and a fixed format is stored in the ROM in advance. As a result, almost no full-time rewriting such as standard formats,
The power required for writing to the display memory 9 can be reduced.

Further, as the controller 15, it is possible to form on the substrate 2 a central processing element which not only handles the display but also executes the calculation and the like, and by doing so, the main parts of the personal computer are integrated and made compact. can do.

In Examples 1 to 5 described above, the metal layer 7 sandwiched between the two insulating layers 6 and 8 is in an electrically floating state, but the metal layer 7 is grounded or a specific potential is applied. It is also effective to fix it to.

[0088]

According to the present invention, low power consumption and
Since the number of parts attached to the frame portion of the effective display area can be reduced and the overall size can be reduced, a liquid crystal display device having a large effective display area can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a liquid crystal display device of Example 1.

FIG. 2 is an operation explanatory diagram of a circuit of the liquid crystal display device of FIG.

FIG. 3 is a schematic configuration diagram of a liquid crystal display device of Example 2.

FIG. 4 is an operation explanatory diagram of a circuit of the liquid crystal display device of FIG.

FIG. 5 is an explanatory diagram of a defect repairing method.

FIG. 6 is a schematic configuration diagram of a liquid crystal display device of Example 3.

FIG. 7 is an explanatory diagram of another defect correction method.

FIG. 8 is a schematic configuration diagram of a liquid crystal display device of Example 5.

[Explanation of symbols]

1 ... 1st substrate, 2 ... 2nd substrate, 3 ... liquid crystal layer, 4 ... scanning electrode, 5 ... signal electrode, 6 ... 1st insulating layer, 7 ... metal layer, 8 ... 2nd insulating layer, 9 ... Display memory, 10 ... Signal side drive circuit, 11 ... Contact, 12 ... Signal side interface, 13 ... Scan side drive circuit, 14 ... Drive circuit chip,
15 ... Controller, 16 ... Data bus, 17 ... First signal side drive circuit, 18 ... First contact, 19 ... Second
Signal side drive circuit, 20 ... Second contact, 21 ... Signal bus line, 22 ... First pad, 23 ... Second pad, 24 ... Correction contact, 25 ... TFT, 26 ... Pixel electrode, 27 ... Source Drive circuit, 28 ... Source side contact, 29 ... Source wiring, 30 ... Gate drive circuit, 31 ...
Gate side contact, 32 ... Gate wiring, 40 ... Disconnection defect.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Nobuhiro Takeda 7-1-1 Omika-cho, Hitachi City, Ibaraki Prefecture Hitachi Ltd. Hitachi Research Laboratory (72) Inventor Toru Sasaki 7-chome, Omika-cho, Hitachi City, Ibaraki Prefecture No. 1 Hitachi Ltd. Hitachi Research Laboratory

Claims (9)

[Claims] 1. A liquid crystal display device having a first substrate on which a transparent electrode is formed, a second substrate opposite to the first substrate and on which an electrode is formed, and a liquid crystal layer sandwiched between the two substrates. In, a memory area for storing image data of a display image is formed on the second substrate, a display area is formed so as to cover the memory area, and a plurality of layers sandwiched between the memory area and the display area. And an equipotential layer sandwiched between the insulating layers. 2. The liquid crystal display device according to claim 1, wherein the equipotential layer sandwiched between the insulating layers is made of a metal thin film. 3. The matrix display according to claim 1, wherein the electrodes formed on the first substrate and the electrodes formed on the second substrate are composed of a plurality of stripe-shaped electrodes which are orthogonal to each other. The described liquid crystal display device. 4. The liquid crystal display device according to claim 3, wherein the memory area for storing the image data is divided into blocks for each column of the display surface. 5. The liquid crystal display device according to claim 1, wherein the memory area for storing the image data is composed of a RAM. 6. The liquid crystal display device according to claim 1, wherein the memory area for storing the image data is composed of a ROM and a RAM, and the ROM stores fixed-size image data. 7. The liquid crystal display device according to claim 1, wherein a central processing element is formed on the second substrate. 8. The liquid crystal display device according to claim 1, wherein the second substrate is single crystal silicon. 9. The liquid crystal display device according to claim 3, wherein a switching element is provided on the second substrate.