JPS62284390A - Display unit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a display device equipped with a TPT (thin film transistor).

[Prior art] In recent years, digital watches, game devices, TVs, etc.
2. Description of the Related Art Display devices that display single numbers, figures, etc. are now on sale on a large scale, and we are now at the dawn of the digital display era.

As typical materials used in these digital display devices, liquid crystal materials are overwhelmingly widely used. By the way, the displayed content or the amount of displayed information tends to increase more and more, and as the amount of information increases,
The reality is that the number of wires from the drive circuit within the display substrate or at the edge of the substrate is increasing.

In order to cope with the increase in the number of drive wiring lines, there is a method of arranging connection terminals for connection with an external drive circuit at the edge of the display board, or a part of the display board other than the display part - the drive line. Display devices are currently being implemented using one of several methods, such as mounting an integrated circuit.

Regarding the former, there have been reports regarding connection technology for reliable connection of individual connection terminal metals. Particularly in areas north of medium-density display devices, where the amount of information is relatively large, manufacturing yields were quite low.

On the other hand, in the latter case, it is possible to mount an integrated circuit on the display substrate (this makes it possible to increase the wiring density from the drive circuit and further reduce the mounting size of the entire display device including the drive circuit). ,Mounting technology i:,It can be said that it is excellent.

Depending on the shape of the chip to be mounted, there are mainly three types of
types, namely dual in-line barra canes (D
IP) type, Tape Automated Honteink (
TAB) type and flip-chip type, both of which had some practical problems.

Among these, the DIP type has a size of 1OII11×
Since it is large (20II11) and the wiring width must be wide, it is not possible to increase the packaging density. T
On the contrary, the AB type and flip-chip type can reduce wiring density to the same level as the pinch density of the bonding pad, which is the external wiring extraction part of the integrated circuit. problems with alignment, and miniaturization of wiring by Azuma, who routed wiring from the four edges of the chip.
Furthermore, a new problem has arisen in that it lacks consistency with the wiring density of the display device substrate. As a result, the display device board ends up becoming larger, and the reliability of the connection between the connection terminals is a serious problem because of the difference in thermal expansion coefficient between the display board and the chip, which tends to cause continuity failures during thermal shock tests. It becomes.

By the way, in medium density liquid crystal display devices, especially in devices for cars 1, a display with a wide viewing angle is desired, and if the number of pixels is small, static drive is used.

However, as the number of pixels increases, static driving becomes difficult, and there is a tendency for Guinamink driving to be performed, albeit at a low duty ratio, and in this case, problems such as a narrow viewing angle are starting to occur.

[Problem that the invention attempts to solve] Unreleased 1! Jl is intended to address the difficulties faced by the prior art in terms of connection technology due to the increase in the number of wiring lines and the consistency of wiring densities between integrated circuits and display substrates.

In addition, the present invention aims to provide a novel improvement in viewing angle by performing static display regarding liquid crystal display devices, especially in display devices for which a wide viewing angle is desired such as those used in automobiles. .

In addition, it is an attempt to eliminate deterioration in reliability F, such as peeling of connection terminals due to differences in thermal expansion coefficients between the drive circuit and the display device substrate due to aging cycles of the display substrate.

[Means for Solving the Problems] The present invention has been made to solve the problems mentioned in @, and in a display element that displays numbers, characters, figures, etc., the display element other than the display portion and the seal portion The present invention provides a display device featuring water, which is equipped with a substrate on which at least one thin film transistor for thin film switching is formed.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic diagram of the basic configuration of the present invention. 2 is a display device substrate, 2 is a transparent electrode substrate (counter substrate), 3 is a sealant bonded part of both substrates, 4 is a substrate on which TPT is formed, and 5 is a signal line which is a group of display wiring wired on the display substrate. Group, 6 is TPT
A scanning gate line group 7 indicates a display electrode group indicating display contents. Also, 8 is a TF connected to the TFT array.
This is a T array signal line group. 9 is the wiring of the counter electrode,
It is usually called a common electrode.

Note that, for the sake of simplicity, the present invention will be described using a liquid crystal display device as an example. In a liquid crystal display device, in the display portion, wiring is normally conducted from the display electrodes on the display substrate to the ends of the substrate. If an attempt is made to increase the amount of display information on these display devices, the number of connection terminals to the drive circuit will naturally increase accordingly. The present invention is implemented to reduce the number of connection terminals. In the present invention, a TFT array is arranged outside the display portion and seal portion of the display substrate as shown in FIG. Second
The figure shows the arrangement of TPT in the present invention.
This is one representative example. Although the number of lines in the gate line group for TPT scanning is three in the description here, the present invention is not limited to this number in any way. Further, FIG. 3 is an equivalent circuit diagram of FIG. 2.

As is clear from these figures, by arranging the TFT array at the edge of the display substrate, the number of connection terminals from the display substrate to the external drive circuit can be reduced by the number of display electrode wirings (i.e., the number of TFT
Number of T array output electrodes, 1l-n-1, l-2~n-2
, 1-3~n-3---1 total 3Xn pieces), TFT
Array signal line group (S-1, S-2, ---9 in this example)
It can be seen that it is possible to reduce the number of lines to n lines)+TFT array gate signal line group (three lines G-1, G-2, and G-3 in this example).

The number of substrates on which this TPT is formed may be one as in the example shown in FIG. 1, or may be divided into two or more substrates.

In the present invention, since the TPT is not directly formed on the substrate of the display device, the display device can be manufactured easily and the yield can be increased. Furthermore, the substrate on which the TPT is formed and the display device can be tested separately and then assembled together, resulting in better workability than inspecting and repairing after one assembly.

In the present invention, the electrodes of the signal lines on the substrate of this display device and the TP
It may be connected to the electrode of the T substrate by a connection technique such as an anisotropic conductive film, soldering, or wire bonding.

Further, by making the substrate of this display device and the substrate of TPT have the same coefficient of thermal expansion, specifically, made of the same material, defects are less likely to occur even in a full cycle test.

[Operation] FIG. 4 shows an example of a block diagram of a drive circuit for driving the display device of the present invention. Display signal generation circuit 10
The shift register 11 addresses the location where the display signal is to be displayed using the synchronization signal generated by the latches 1 and 12. It will be remembered.

When the input of the display signal to the latch-1 is completed, the display signal generation circuit should then address the gate scanning shift register 15.

When the gate line is selected, the display signals stored in the latch 1 pass through the output inversion circuit 14 and are simultaneously input to the display signal line group of the TFT array without being inverted.

By the way, at the same time that the input of the display part number 1 to the latch-1 ends, a timing signal is sent from the signal generation circuit to start inputting the display signal to the latches-2 and 13. At this time, the display signals already stored in latch-1 are swept out all at once. At the same time as the input of the display signal to latch-2 is finished, the input of the display signal to latch-1 is started again in the same way, but this time, the display signals that have already been input to latch-2 are input all at once. Sweep it out. The display signal swept out from the latch-2 is inputted to a different display location from the one described above by selecting the gate line next to the aforementioned gate line by the gate scanning shift register. Lunch 1 display part number like this-1
, a so-called line-sequential method is used in which alternate switching of inputs to latch-2 and alternate sweep-out and sequential selection of gate lines are performed.

Furthermore, in the drive circuit, when a series of gate line scans (1 field) is completed, the display signal generation circuit outputs an activation signal for the latch output inverting circuit [4], and a subsequent series of gate line scans (1 field) is output from the display signal generation circuit. field) sometimes latch-1
All the display signals swept out from latch-2 are inverted by this latch output inverting circuit. In this way, the output inversion circuit completes the inversion operation when the display signal generation circuit issues an inversion release signal upon completion of a series of gate line scans (l field). By performing the latch output inversion operation every cycle of a series of gate scans in this manner, the liquid crystal is AC driven.

FIG. 5 shows an example of the timing chart of the above-mentioned driving. For the sake of simplicity, the number of gate lines is G-1, G
-2, G~3 and three.

Lunch-1 includes N-1, N-2, N-3---N-
n.

Latch-2 has N'-1, N'-2, N'-3----
There are n memories, N'-n, respectively, and the display signal is alternately input as latch = latch-2.

On the other hand, the timing chart when driving the TPT shows G-1, G-2, and G-3 as gate signals. Furthermore, gate signal G-1 is selected;

The display electrode signal when S-1, S-2---S-n is input as the TPT input signal is il----n-1
The waveform will be Furthermore, the TPT input signals S-1, S-2---S-n and display electrode signals when the gate signals G-2 and G-3 are selected are shown.

As described above, it can be seen that the arrangement of the TFT array on the display substrate according to the present invention has no problems with the liquid crystal driving method and can be driven satisfactorily.

In addition, for medium-density displays such as those used in automobiles that require low duty ratio drive, the technology of the present invention makes it possible to display with static drive, which significantly reduces visual dependence. This is what we provide.

[Example] ITOII, which is a transparent electrode, was deposited on a 100×150 mm glass substrate by electron beam evaporation. Next, IT
A desired display electrode was formed on the O film by a photolithography process. At this time, a total of 150 wires were required to display three-digit numbers and an analog tachometer display. Further, display electrodes were formed on a counter substrate facing the same substrate by the same photolithography process.

As the glass substrate, we used a low alkali glass substrate (R7059J manufactured by Corning) and a normal plate glass substrate. 2
Deposition+in CV D Method V-YorStO;+M
was used.

Incidentally, a spacer made of particulate plastic was used between the display substrate and the counter substrate to adjust the cell cap, and a polyimide alignment film was applied to each substrate and rubbed. Further, outside the display portion and seal portion of the display substrate, the portion where the TFT array is mounted was previously plated with Ni (electroless plating).

On the other hand, the TPT substrate had a size of 82×3 mm+, and was of the same type as the display substrate in order to match the coefficient of thermal expansion. In this case, in the case of a plate glass substrate, about 4
000 of 5INx was deposited by plasma CVD to serve as an alkali blocking layer. A TFT trial fabrication process which is normally carried out on this substrate was carried out, and a 50.times.3 TFT array as shown in FIG. 2 was fabricated. The size of the TPT was 50 mm/L, and the line width of the wiring was 50 lm for the gate signal line, signal line, and signal output line. Furthermore, the TPT repetition pitch was set to 400 pm pitch.

This reduces the line density wired on the display board to a pitch of 400 lm (250 lines, 150 lm space).
As a result of setting this and obtaining consistency during TPT mounting, it was possible to easily obtain a connection yield of 100% for connection terminals.

The connection between the TPT wiring and the wiring on the display board is an anisotropic conductor 1r.
The test was carried out using L membrane (“Anisolm” manufactured by Hitachi Chemical Co., Ltd.).

A liquid crystal display device using a substrate on which a TPT is formed in this manner can be statically driven despite the large number of signal lines in the display device, and can be driven with a wide viewing angle.

[Effects of the Invention] The present invention makes it possible to significantly reduce the number of connection terminals for one display device with an external circuit by mounting a board on which at least one switching TPT is formed on the display board. This has excellent effects in manufacturing display devices.

According to the present invention, in general, the signal line group of the TFT array is
In this book, the TPT array gate signal line group is formed into m trees (where n>m
), it is usually possible to drive up to nXm display electrodes, and in this case, the number of connection terminals with the external drive circuit is n
This makes it possible to reduce the number of wires to 10 m, which has the effect of improving yield.

In addition, by making the material of the display substrate and the TPT substrate the same, the results of a thermal cycle test in which the temperature was changed between -30°C and ÷100°C in a short period of time showed that the connection terminals could not be peeled off due to the difference in the thermal expansion coefficient of the substrate. etc. does not occur at all and has an excellent effect in terms of reliability.

In addition, by increasing the number of source lines than the number of gate lines, a horizontally elongated TPT substrate can be created, so the electrodes of the display substrate can be patterned at a pitch of 4004 m (250 final l lines, 150 loose spaces) in one direction. It is also effective in improving yield during patterning.

The number of input source lines equal to the number of display electrodes/the number of gate electrodes is taken out from the opposite side of the display electrode and connection part of the TPT substrate, and the number of input source lines taken out from the display substrate is reduced to input source lines + gate lines + common lines. Since it can be statically driven by TPT switching, it has the advantage of providing good viewing angle and contrast.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a display device in which a TFT array is mounted on one end of a display substrate. FIG. 2 is a plan view of the TFT array, and FIG. 3 is an equivalent circuit diagram of the TFT array of FIG. FIG. 4 is a block diagram of a driving circuit for driving the display device of FIG. 1, and FIG. 5 shows a timing chart for driving the display device of FIG. 1. 1-m-display device substrate 2-m=transparent electrode substrate 3-m-sealant adhesive portion 4--substrate on which TPT is formed 5-m-signal line group which is a display array group wired on the display substrate 6---TPT scanning gate line group 7---, display electrode group 8---TFT array signal line group 9-11 common electrode line 1O---1 display signal generation circuit 11-m-shift register ( For signals) 12-m-latch-1 13-m-latch-2 14-m-latch output inversion circuit 15---Shift register (for gate scanning) Han Gaku! 51zl (s,) Female Worker't JEL I Umoriko Itoda t2-7F1j Seisho July 1986,) 7th

Claims (4)

[Claims] (1) In display elements that display numbers, characters, figures, etc.
On the substrate other than the display part and seal part, at least one
A display device characterized by mounting a substrate on which three or more thin film transistors for switching are formed. (2) The display device is a liquid crystal display device using at least one transparent electrode substrate and an electrode substrate facing the transparent electrode substrate at a predetermined interval, and filling the gap with liquid crystal. Display device according to scope 1. (3) The substrate on which the thin film transistor is formed is a thin film transistor array formed by arranging a plurality of thin film transistors, and the number of source lines, which are signal lines, is greater than the number of gate lines, which are scanning lines. Display device as described in section. (4) The display device according to claim 1, wherein the substrate on which the thin film transistor is formed is made of the same material as the display electrode substrate.