JPH0412327A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To easily manufacture this liquid crystal display device at low cost although the device is equipped with display driving circuits by constituting the display driving circuits by forming many thin film transistors on substrates other than glass substrates where display electrodes are formed, and fitting driver elements which constitute this display driving circuits to terminal array edge parts of the glass substrates. CONSTITUTION:The display driving circuits 22a and 22b are constituted by forming many thin film transistors 23a and 23b on the striped substrates 21a and 21b other than the glass substrates 11 and 12 where the display electrodes 14 and 15 are formed, and the driver elements 20a and 20b which constitute the display driving circuits are fitted to the terminal array edge parts of the glass substrates 11 and 12. Then the driver elements 20a and 20b are only fitted by being connected to driving circuit connection terminals 14a and 15a at the terminal array edge parts of the glass substrates 14 and 15 to manufacture the liquid crystal display device equipped with the display driving circuits. Consequently, the manufacture is facilitated and the display driving circuits can be greatly reduced in cost.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a liquid crystal display device.

[Conventional technology]

A matrix-type liquid crystal display device that displays television images, etc. has display electrodes formed on the surfaces of a pair of glass substrates facing each other with a liquid crystal layer in between. A simple matrix type in which a large number of striped scanning electrodes are arranged parallel to each other on one surface, and a large number of striped signal electrodes orthogonal to the scanning electrodes are arranged parallel to each other on the other glass substrate surface; On one glass substrate surface, there are many pixel electrodes and thin film transistors that selectively drive each pixel electrode (
There is a TPT active matrix type in which TPT) are arranged vertically and horizontally and a counter electrode is formed on the other glass substrate surface.

Incidentally, recently, as the above-mentioned matrix type liquid crystal display device, one in which the display drive circuit is provided at the edge of the terminal arrangement of the glass substrate has been considered.

5 and 6 show a conventionally known liquid crystal display device equipped with a display drive circuit. Note that this liquid crystal display device is of a simple matrix type.

In Figures 5 and 6, 1 and 2 are liquid crystal layers LC.
The glass substrates 1.2 are a pair of glass substrates facing each other with the liquid crystal enclosed area in between, and the glass substrates 1.2 are bonded to each other via a frame-shaped sealing material 3 surrounding the liquid crystal sealed area. Of the pair of glass substrates 1 and 2, a large number of striped scanning electrodes (transparent electrodes) 4 are formed on one surface of one glass substrate (the upper substrate in the figure) and arranged in parallel with each other. A large number of striped signal electrodes (transparent electrodes) 5 are arranged in parallel to each other and are perpendicular to the scanning electrodes 4 on the 2nd surface of the glass substrate (lower substrate in the figure). Alignment films 6a and 6b are formed on the formation surfaces, respectively. In this liquid crystal display device, in order to lower the display drive duty ratio, the signal electrodes 5 are separated in the middle in the length direction, and each signal electrode 5 is individually driven.

Further, 7a is a plurality of scanning side drive circuit elements (two in the figure) attached to one end edge of one glass substrate 1, and 7b
denotes a plurality of signal side drive circuit elements (four in the figure) attached to both side edges of the other glass substrate 2, and each scanning side drive circuit element 7a connects its output terminal to one side of the glass substrate 2. Driving circuit connection lead wires 4a are led out from the ends of each of the scanning electrodes 4 and wired on the glass substrate 1 surface.
Each signal side drive circuit element 7b has its output terminal led out from the end of each signal electrode 5 to the other glass substrate 1 surface and wired. The drive circuit connection lead wire 5a is connected to the end of the drive circuit connection lead wire 5a by soldering or the like. Note that 8a is a wiring for external circuit connection wired on one surface of the one glass substrate, and 8b is a wiring for external circuit connection wired on the second surface of the other glass substrate. The input terminal is connected to each of the external circuit connection wirings 8a, 8b by solder or the like. Further, each of the drive circuit elements 7
As for a and 7b, a large number of MO5 are formed on a single crystal silicon substrate.
An IC chip in which a type transistor is formed is used, and the scanning side display drive circuit and the signal side display drive circuit are formed by the plurality of drive circuit elements (IC chips) 7a and 7b, respectively.
It is made up of.

Although a simple matrix type liquid crystal display device is shown in FIGS. 5 and 6, conventionally, even in a TPT active matrix type liquid crystal display device, the display drive circuits on the scanning side and the signal side are each formed from an IC chip. Each drive circuit element is attached to the edge of one of the glass substrates on which a pixel electrode and a thin film transistor for selectively driving the pixel electrode are formed. This TP
In the case of a T active matrix type liquid crystal display device, each terminal of each scanning side drive circuit element is connected to a lead wire derived from a scanning line (gate line) connected to the gate electrode of a thin film transistor for pixel electrode selection and driving, and Each terminal of the side drive circuit element is connected to a lead wire led out from a data line connected to the drain electrode of the thin film transistor.

[Problem to be solved by the invention]

However, in the above-mentioned conventional liquid crystal display device, the display drive circuit is configured by attaching a plurality of drive circuit elements made of IC chips to a glass substrate on which display electrodes are formed. must be attached one by one by connecting each output terminal to each lead wire wired on the surface of the glass substrate, which makes manufacturing of the liquid crystal display device troublesome. Since the IC chip formed with a large number of MO8 type transistors is expensive, the cost of the display driving circuit is high, making it difficult to reduce the manufacturing cost of the liquid crystal display device.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to provide a liquid crystal display device that is equipped with a display drive circuit and that can be manufactured easily and at low cost. It is about providing.

[Means to solve the problem]

In the liquid crystal display device of the present invention, the drive circuit connection terminals of each display electrode formed on the surface of the glass substrate are arranged along the edge of the glass substrate, and at least one of the drive circuit connection terminals of the display electrodes formed on the glass substrate is arranged along the edge of the glass substrate. A driver element, which constitutes a display drive circuit by forming a large number of thin film transistors using polysilicon semiconductors on a rectangular substrate made of heat-resistant glass with a length corresponding to the entire terminal array area, is attached to one side edge of the substrate. Each of the arranged output terminals is connected to and attached to each drive circuit connection terminal at the edge of the terminal array.

[Effect]

That is, in the present invention, a display drive circuit is formed by forming a large number of thin film transistors on a strip-shaped substrate different from a glass substrate on which display electrodes are formed, and a driver element forming this display drive circuit is attached to the glass substrate. According to the present invention, each of the output terminals of the driver element arranged on one edge of the driver element is connected to each drive circuit connection terminal on the edge of the terminal array of the glass substrate. A liquid crystal display device equipped with a display drive circuit can be manufactured by simply attaching the display drive circuit to a glass substrate on which display electrodes are formed. It is easier to manufacture than conventional liquid crystal display devices, and the display drive circuit made of the thin film transistors has a large number of MO3 on a single crystal silicon substrate.
Since it can be obtained at a much lower cost than an IC chip on which a type transistor is formed, the cost of the display drive circuit can also be significantly reduced.

Moreover, in the present invention, the thin film transistor constituting the display drive circuit of the driver element uses a polysilicon semiconductor, and the thin film transistor using this polysilicon semiconductor is different from the MO3 type transistor using a single crystal silicon substrate. However, since the operation speed is considerably faster than that of a thin film transistor using a normal amorphous silicon semiconductor, the display drive circuit of the driver element should be operated at a speed sufficiently high to drive the display of a liquid crystal display device. I can do it. In addition, since the polysilicon semiconductor is formed by heat treatment at high temperature,
In order to configure the display drive circuit of the driver element with a thin film transistor using a polysilicon semiconductor, the substrate of the driver element must be a heat-resistant glass substrate. A small, strip-shaped substrate with a length that corresponds to the entire terminal arrangement area of the formed glass substrate is used, therefore, the amount of expensive heat-resistant glass used can be reduced, and the large area on which the display electrodes are formed can be used. Since the glass substrate may be an inexpensive ordinary glass substrate that does not require heat resistance, the manufacturing cost of the liquid crystal display device can be reduced.

〔Example〕 Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

1 and 2 show the structure of the liquid crystal display device of this embodiment. The liquid crystal display device of this embodiment is of a simple matrix type, and 11 and 12 in the figure are a pair of glass substrates facing each other with a liquid crystal layer LC in between.
1.12 are all made of ordinary glass substrates such as Nesa Glass.

Note that the pair of glass substrates 11 and 12 are bonded together via a frame-shaped sealing material 13 that surrounds the liquid crystal sealed area.

Of the pair of glass substrates 11 and 12, a large number of striped scanning electrodes (transparent electrodes) 14 are arranged parallel to each other on the 11 surface of one glass substrate (the upper substrate in the figure), and the other On the 12th surface of the glass substrate (lower substrate in the figure), a large number of striped signal electrodes (transparent electrodes) 15 orthogonal to the scanning electrodes 14 are arranged parallel to each other. Alignment films 16a and 16b are formed on the electrode formation surfaces, respectively. In the liquid crystal display device of this embodiment, in order to reduce the display drive duty ratio, the signal electrodes 15 are separated in the middle in the length direction, and each signal electrode 15 is individually driven. There is.

Further, the ends of each scanning electrode 14 formed on the surface of the one glass substrate 11 are
The ends of each signal electrode 15 that is led out to the terminal array edge of one end edge and used as the scanning side drive circuit connection terminal 14a, and formed on the other surface of the substrate 12 are connected to both sides of the other glass substrate 12. The signal side drive circuit connection terminals 15a are led out to the edge of the terminal array on the edge, and each scanning side drive circuit connection terminal 14a is arranged in a row along the edge of the terminal array of one glass substrate 11. The signal-side drive circuit connection terminals 15a are arranged in one row along the edge of each terminal arrangement of the other glass substrate 12.

On the other hand, 20a is a scanning side driver element attached to the terminal array edge of one glass substrate 11, and 20b is a signal side driver element attached to each terminal array edge of the other glass substrate 12.

Each of the driver elements 20a, 20b has a length of the terminal array area of the terminal array edge of the one glass substrate 11 and the terminal array edge of the other glass substrate 12, respectively, as shown in FIGS. a rectangular substrate 21a slightly longer than that;
A large number of thin film transistors (hereinafter referred to as driver TPTs) 23a, each of which uses polyφ silicon as a semiconductor, are disposed on 21b.
23b is formed to constitute the scanning side display drive circuit 22a and the signal side display drive circuit 22b.
It is constructed by laminating a gate electrode, a gate insulating film, a polysilicon semiconductor layer facing the gate electrode with the gate insulating film interposed therebetween, and a source electrode and a drain electrode. The polysilicon semiconductor layer is made by heating a deposited layer of amorphous silicon at a high temperature to make it poly, and therefore the substrates 21a and 21b are made of quartz glass that can withstand the heat treatment that makes amorphous silicon poly. It is said to be a heat-resistant glass substrate such as.

The scanning side driver element 20a connects each output terminal 24a led out from the display driving circuit 22a to one side edge of the substrate 21a to each scanning side driver element 24a on one glass substrate 11 on which the scanning electrode 14 is formed. They are connected to the circuit connection terminals 15a and attached to the terminal arrangement edge of one of the glass substrates 11, and each signal side driver element 2
0b connects each output terminal 24b led out from the display drive circuit 22b to one side edge of the substrate 21b to the signal electrode 15.
are connected to the respective signal side drive circuit connection terminals 15b on the other glass substrate 12 formed with a Signal side driver elements 20a, 20
Each output terminal 24a, 24b of the glass substrate 11
．． The respective output terminals 24a, 24b are arranged at a pitch corresponding to the arrangement pitch of each of the drive circuit connection terminals 15a, 15b on the drive circuit connection terminal 15a, 12.
15b by solder 26 or the like.

Further, in FIG. 1, 27 indicates each driver element 20a,
This is the driver element fixing resin sold between the glass substrate 20b and the glass substrate 1112.

Also, a part of the other side edge of the substrate 21a of the scanning side driver element 20a and the substrate 2 of each signal side driver element 20b
The display drive circuit 22 is provided at one end edge of 1b.
A plurality of input terminals 25a, 25b derived from a, 22b
are formed, and these input terminals 25a, 25b are connected to the glass substrate 1 on which the scanning electrode 14 and the signal electrode 15 are formed.
Relay wiring 28a for external circuit connection wired at 1°12.

It is connected to 28b by solder or the like.

FIG. 4 is a block circuit diagram of the display drive circuit 22b configured in the signal side driver element 20b.

This display drive circuit 22b consists of a shift register 31 with a number of stages corresponding to the number of signal electrodes of the liquid crystal display device, and a level shifter 32 with the same number of stages as this shift register 31, and the shift register 31 receives input from an external circuit. The binary image data signals are sequentially captured in synchronization with the shift clock. The image data for one scanning line taken up to the last register of the shift register 31 is transferred from the shift register 31 to the level shifter in synchronization with a synchronization clock (scanning timing signal) inputted to the level shifter 32 from an external circuit. 32. Further, the level shifter 32 converts the image data for one scanning line into an output voltage corresponding to the voltage of a power source (binary power source) supplied from an external circuit.
This signal is output as an N level (high level) and OFF level (low level) signal to each data line 5 in synchronization with the next synchronization clock, and at the same time, image data for the next one scanning line is output. Take in from shift register 31.

Although not shown, the display drive circuit 22a configured in the scan side driver element 20a is a shift register with a number of stages corresponding to the number of scan electrodes of the liquid crystal display device, similar to the display drive circuit 22b of the signal side driver element 20b. and a level shifter with the same number of stages as this shift register, and a display drive circuit 22a of this scanning side driver element 20a.
sequentially outputs a selection signal to each scanning electrode 14. In addition,
The display driving circuit 22a of the scanning side driver element 20a only receives a signal inputted from an external circuit to the shift register as a scanning electrode selection signal rather than an image data signal, and the basic operation is that of the signal side driver element 20b. This is the same as the display drive circuit 22b.

That is, the liquid crystal display device of this embodiment includes each glass substrate 1 on which a display scanning electrode 14 and a signal electrode 15 are formed.
1. A large number of driver TFTs 23 a and 23 b are formed on strip-shaped substrates 21 a and 21 b different from 1.12 to constitute scanning side and signal side display drive circuits 22 a and 22 b, and a scanning side display drive circuit is formed. 22a and the signal side driver element 20b forming the signal side display drive circuit 22b are connected to each glass substrate 11.
．． Each terminal is attached to the edge of the 12 terminal arrays.

According to this embodiment, the driver element 20a.

20b, each output terminal 24a, 2 arranged on one side edge.
4b to each drive circuit connection terminal 14a, 15a on the edge of the terminal array of the glass substrate 11.12, a liquid crystal display device equipped with a display drive circuit can be manufactured. Compared to a conventional liquid crystal display device in which a display drive circuit is constructed by attaching drive circuit elements one by one to a glass substrate on which display electrodes are formed, manufacturing is simpler, and the driver TFT 23a, 2
A display drive circuit 22a consisting of 3b.

22b is the display drive circuit 22a because it can be obtained at a much lower cost than an IC chip in which a large number of MO8 type transistors are formed on a single crystal silicon substrate.

The cost of 22b can also be significantly reduced.

Moreover, in the liquid crystal display device of this embodiment, the driver TFTs 23a and 23b constituting the display drive circuits 22a and 22b of the driver elements 20a and 20b are made of polysilicon semiconductors. The TPT using the driver elements 20a, 20 has a considerably faster operating speed than the TPT using the ordinary amorphous silicon semiconductor, although it is different from the MO3 type transistor using the single crystal silicon substrate.
The display drive circuit b can be operated at a sufficiently high speed for display drive of a liquid crystal display device. Further, since the polysilicon semiconductor is formed by heat treatment at high temperature, the display drive circuit 2 of the driver elements 20a and 20b
2a.

22b is a TFT 23a using a polysilicon semiconductor,
23b, the substrates 21a and 21b of the driver elements 20a and 20b must be heat-resistant glass substrates such as quartz glass.
substrate 21a.

21b may be a small rectangular substrate slightly longer than the length of the terminal arrangement area of the glass substrate 11.12 on which the display scanning electrode 14 and signal electrode 15 are formed, so that the amount of expensive heat-resistant glass used can be reduced. Furthermore, the large-area glass substrates 11 and 12 on which display electrodes (scanning electrodes 14 and signal electrodes 15) are formed may be ordinary inexpensive glass substrates (such as Nesa glass substrates) that do not require heat resistance. Therefore, the manufacturing cost of the liquid crystal display device can be reduced.

Further, in the liquid crystal display device, the driver element 20a
, 20b are glass substrates, and the substrates 21a, 21b and the glass substrates 11°12 forming the display electrodes 14.15 have different heat resistances but almost the same coefficient of thermal expansion. From, display electrode 14.1
A driver element 20a has display driving circuits 22a and 22b formed on strip-shaped substrates 21a and 21b that are slightly longer than the length of the terminal array area.
, 20b are attached, there is no possibility of peeling at the connecting portion of the driver elements 20a, 20b due to fat expansion and contraction due to temperature changes.

Note that in the above embodiment, the scanning electrode 14 and the signal electrode 1
5 is connected to the drive circuit connection terminal 14a.

15a, but this drive circuit connection terminal 14a, 1
5a may be formed at the ends of lead wires led out from the scanning electrodes 14 and signal electrodes 15. In that case, the lead wires are bent and wired to connect each drive circuit connection terminal 14a, 15a. may be arranged at a pitch different from that of the scanning electrodes 14 and the signal electrodes 15. Further, if the substrates 21a and 21b of the driver elements 20a and 20b have a length corresponding to the entire terminal array area of the glass substrate 11 and 12 on which at least display electrodes (scanning electrodes 14 and signal electrodes 15) are formed, Its length may be arbitrary.

However, the substrate 21a of these driver elements 20a, 20b
, 21b is a glass substrate 11.1 on which display electrodes are formed.
It is desirable to have a length that does not protrude outward.

Furthermore, although the liquid crystal display device of the above embodiment is of a simple matrix type, the present invention can also be applied to a TPT active matrix type liquid crystal display device. The thin film transistor for pixel electrode selection does not require very high speed operation due to the responsiveness of the liquid crystal, so a normal thin film transistor using an amorphous silicon semiconductor can be used.)
Drivers similar to those in the above embodiment are installed at the edge of the array of scan line terminals and the edge of the array of data line terminals of one glass substrate on which scan lines and data lines connected to the gate electrode and drain electrode of the thin film transistor are formed. It is sufficient to attach each element.

[Effects of the Invention] The present invention comprises a display driving circuit formed by forming a large number of thin film transistors on a strip-shaped substrate different from a glass substrate on which display electrodes are formed, and a driver element comprising this display driving circuit. is attached to the edge of the terminal array of the glass substrate, and according to the present invention, each output terminal arranged on one side edge of the driver element is connected to each drive circuit on the edge of the terminal array of the glass substrate. It is possible to manufacture a liquid crystal display device equipped with a display drive circuit by simply connecting it to the connection terminal and installing it.
It is easier to manufacture than a conventional liquid crystal display device in which a display drive circuit is constructed by attaching a plurality of drive circuit elements each made of C chips to a glass substrate on which display electrodes are formed. Furthermore, since the display drive circuit made of the thin film transistors can be obtained at a much lower cost than an IC chip in which a large number of MO3 type transistors are formed on a single crystal silicon substrate, the cost of the display drive circuit can also be significantly reduced.

Furthermore, in the present invention, the thin film transistor constituting the display drive circuit of the driver element is made of a polysilicon semiconductor, and the thin film transistor using this polysilicon semiconductor is different from the MO8 type transistor using a single crystal silicon substrate. However, since the operation speed is considerably faster than that of a thin film transistor using a normal amorphous silicon semiconductor, the display drive circuit of the driver element should be operated at a speed sufficiently high to drive the display of a liquid crystal display device. I can do it. In addition, since the polysilicon semiconductor is formed by heat treatment at high temperature,
In order to configure the display drive circuit of the driver element with a thin film transistor using a polysilicon semiconductor, the substrate of the driver element must be a heat-resistant glass substrate. A small, strip-shaped substrate with a length corresponding to the entire terminal arrangement area of the formed glass substrate is sufficient, so the amount of expensive heat-resistant glass used can be reduced, and a large-area glass substrate on which display electrodes are formed can be used. Since the substrate may be an inexpensive ordinary glass substrate that does not require heat resistance, the manufacturing cost of the liquid crystal display device can be reduced.

[Brief explanation of drawings]

1 to 4 show an embodiment of the present invention, and FIG. 1 is a cross-sectional view taken along the line II in FIG. 2, and a Glock circuit diagram of the display drive circuit. FIG. 5 is a plan view of a conventional liquid crystal display device, and FIG. 6 is an enlarged sectional view taken along the line Vl--Vl in FIG. LC...Liquid crystal layer, 11.12...Glass substrate, 14
... Scanning electrode (display electrode), 5... Signal electrode (display electrode), 14a, 15a... Drive circuit connection terminal, 20a... Scanning side driver element, 20b... Signal side driver Element, 21a, 21b...Strip substrate (heat-resistant glass substrate), 22a, 22b...Display drive circuit, 23a, 23b...Thin film transistor using polysilicon semiconductor, 24a, 24b...Output terminal. Applicant's agent Patent attorney Takehiko Suzue

Claims (1)

[Claims] In a liquid crystal display device in which display electrodes are formed on the surfaces of a pair of glass substrates facing each other with a liquid crystal layer in between, drive circuit connection terminals of each display electrode formed on the glass substrate surfaces are connected to the edges of the glass substrates. Along with arranging the
A display drive circuit is formed by forming a large number of thin film transistors using polysilicon semiconductors on a strip-shaped substrate made of heat-resistant glass having a length corresponding to at least the entire terminal arrangement area of the glass substrate at the terminal arrangement edge of the glass substrate. 1. A liquid crystal display device characterized in that a driver element comprising a driver element is mounted with output terminals arranged on one side thereof connected to respective drive circuit connection terminals on the edge of the terminal arrangement.