JPH0316028B2 - - Google Patents

Description

[Detailed Description of the Invention] <Technical Field> The present invention relates to a display device having a display panel,
In particular, the present invention relates to a high-density information display device, such as an image display, in which a display medium is interposed between a transparent substrate having a transparent conductive film and a counter substrate having switching elements arranged in a matrix.

<Prior art> Conventionally, a flat image display device using, for example, a liquid crystal as a display medium interposed between a pair of substrates and a thin film transistor (hereinafter abbreviated as TFT) as a switching element has been developed, and its practical use has been progressing. is being promoted. FIG. 1 is a basic circuit diagram showing the main structure of such an image display device. A single pixel of the image display device consists of a TFT 1, a display electrode 2, a transparent electrode 3, and a liquid crystal 4. When displaying an image as a display panel, a gate line Gi and a source line Sj are used as wiring conductors for driving the TFT 1, respectively. More than 240 pixels are arranged in a matrix, and the number of pixels is nearly 60,000. Gate line Gi and source line
Sj extends from one end of the display panel to the other end, and must be formed to have a sufficiently longer length and a wider area than a general IC. Therefore, the gate line G
1. Disconnection or shorting of source line Sj, TFT
There is a high risk of occurrence of defects, etc., which causes a decrease in the yield of display panels.

In order to prevent the above defects of the display panel, the gate line
Separate lines from both ends of Gi, Gi′ and source lines Sj, Sj′
There is a method of inputting the same signal for LSI, but 1
Two LSIs are required to drive one line, and as the connection pitch becomes finer, the yield decreases due to microfabrication, and the increase in the number of driving LSIs increases costs. Usually a screwdriver
In order to reduce the number of LSIs and widen the connection pitch of gate lines Gi and source lines Sj, the connection terminals are formed with the odd numbered gate lines and source lines on one side and the even numbered lines on the other side. A method is used in which the lines are expanded twice and each line is driven from one side. For points where shorts occur at the intersection of gate lines and source lines, and defective points in the TFT, burn out the nearby gate lines or source lines with a laser, etc.
It is separated from other pixels by intentionally breaking the wire. In these cases, the result is the same as a disconnection of the gate line and source line themselves, and a line defect occurs after the disconnection point. In display devices that mainly display moving images such as television images, line defects are very noticeable, but point defects are almost invisible. For this reason, it has been proposed to convert line defects in display panels into point defects. This structure will be explained below.

(1) The first structure will be explained with reference to FIG.

A display panel includes a first substrate 11 (e.g., a glass substrate) on which TFTs 1 and display electrodes 2 are formed in a matrix, and a second substrate (e.g., a glass substrate) on which a common electrode 3 is formed (not shown), in which liquid crystal is sealed. If the source line 13 is disconnected, a third substrate (for example, a glass substrate) 14 having a larger external shape is provided separately from the first substrate 11, and the wiring electrode 15 is formed on the third substrate 14. The first substrate 11 and the third substrate 14 are adhesively fixed, and the output terminal e ₁ of the source driver and the terminal a ₁ of the source line 13 of the first substrate 11 are connected to establish electrical continuity. Next, the output terminal e ₁ and the terminal b ₁ of the third board 14 are connected, and the other terminal c ₁ on the third board 14 and the other terminal d ₁ of the source line 13 are connected.
Connect with. This causes the source signal to
It is supplied to pixels except _B1 , and a normal image is obtained by treating line defects as point defects. The disadvantage of this structure is that the third board 14 must be placed over the first board 11, so there is no suitable connection means on a mass-produced basis for connecting the terminals a ₁ - e ₁ , such as a source driver. and output terminal
e ₁ is mounted on a flexible wiring board (hereinafter referred to as FPC), and when the output terminal e ₁ and the terminal a ₁ on the first board 11 are simultaneously connected to multiple terminals, a third terminal located at the bottom of the FPC is used. The connection with the board 14 is
This causes inconveniences such as being unable to do so due to FPC being an obstacle.

(2) The second structure will be explained with reference to FIG.

As a means for improving the first structure, a structure using a printed circuit board (hereinafter referred to as PWB) as an auxiliary board will be described. FIG. 3A is a plan view showing the second structure, and FIG. 3B is a sectional view taken along line F-F' of A. In the figure, 11 is the first substrate, 12 is the second substrate, 24 is the source line, 21 is the PWB, and 22 is the
Correction wiring on the PWB, 23 indicates the FPC. The gate line and source line drivers of the first substrate 11 are mounted on the FPC 23, and the electrodes (not shown) on the FPC and the electrodes _l2 on the first substrate 11 are connected to the first substrate 11.
A multi-terminal connection is made on the outer periphery of the board 11. After this, the PWB 21 is placed and fixed on top of the FPC 23. If a disconnection _B2 occurs on the display panel,
A source signal is supplied between terminals a ₂ and B ₂ of the source line 24, but not between terminals B ₂ and d ₂ .
Connecting the terminal a ₂ of the source line 24 to which the source signal is supplied and the terminal b ₂ on the PWB 21, and connecting the other terminal c ₂ and the other terminal d ₂ on the source line 24 through the wiring 22. line defects are removed. However, in this case FPC
In order to place the PWB 21 on top of the 23, there is a gap of 1 mm to 1 mm between the terminals (a ₂ , d ₂ ) on the first board 11.
A 1.5 mm step difference occurs, which is very disadvantageous when connecting using thin metal wire. Furthermore, even if a display defect is discovered during the testing stage of the display panel, the display defect cannot be corrected until after multi-terminal connection is made to the FPC 23 on which drivers and the like are mounted, and the PWB 21 is placed and fixed thereon. Furthermore, even if an attempt is made to reduce the area of the display device including the display area by bending the FPC 23 connected to the first substrate 11, there is a drawback that the area occupied by the PWB 21 will obstruct the area.

In addition to the above, the first structure requires a process of bonding the first substrate 11 and the third substrate 14, and the second structure requires a process of fixing the first substrate 11 and PWB 21 and fixing parts. , both of which lead to increased costs.

<Object of the Invention> The present invention has been made in order to eliminate the above-mentioned conventional drawbacks, and provides a display device that can easily correct defects that occur on the display panel at any time after the completion of the display panel manufacturing process. The purpose is to provide.

<Embodiment> FIG. 4A is a configuration diagram of a display panel section explaining one embodiment of the present invention, and FIG. 4B is a sectional view taken along line X-X'.
a first substrate 11 on which switching elements arranged in a matrix and metal wiring (source lines and gate lines) for driving the switching elements are formed;
a first substrate 1 disposed opposite to the first substrate 11;
A display cell is formed with a second substrate (glass substrate) 12 on which a counter electrode of a transparent conductive film smaller than 1 is formed, and a field-effect nematic liquid crystal is sealed in the cell. A display panel is manufactured in which the overlapping region of the second substrate 12 serves as a display screen. The metal wiring and the counter electrode are connected to a drive circuit, and the liquid crystal is driven for display. That is, by selectively controlling the switching elements on and off by appropriately selecting the metal wiring extending outward from the display screen from one edge of the display screen to the other edge, the drain directly connected to the switching element is connected. The electro-optical characteristics of the liquid crystal interposed between the electrode and the counter electrode change, and a matrix display corresponding to the selection of the switching elements is performed. in this case,
The display pattern is visible to an observer via the second substrate 12. In such a liquid crystal display device, metal wiring and an insulating layer are formed at the stage of manufacturing the display panel, and these are used to form a second layer on the first substrate 11.
A source line 32 made of a first metal is extended to the outer region of the substrate 12 to form a terminal h for connection between the correction terminals a ₃ and d ₃ and the FPC 31 on which the source driver is mounted. Also, the source line 32 is connected to the substrate 1.
After forming an insulating layer 34 on the region extending to both outsides of the source line 32, a correction wiring 33 is formed using a second metal in a direction substantially perpendicular to the source line 32. After the end of the correction wiring 33 is bent at a right angle, the first
The external connection is made at the edge of the substrate 11. Formed on the correction wiring 33 are terminals b ₃ and c ₃ that serve as first and second connection parts that can be electrically connected to the externally extending portions of the source line 32 on the left and right sides of the display panel, respectively. . These b ₃ and c ₃ are correction terminals of the source line 32
It is lead-connected to a ₃ and d ₃ and is disposed near the source line 32. The line width of the correction wiring 33 is approximately twice that of the source line 32 in the display area.
The line spacing is also made to be approximately equal to the line width. Furthermore, if the insulating layer 34 is made appropriately thick, even if a defect such as a break or a short occurs in the source line 32 or the gate line (not shown), such a defect will hardly occur in the correction wiring section 33. . After manufacturing the display panel 11, if a defective part B3 is found in the source line 32 and a disconnection occurs in an electrical test, a source signal is normally supplied from terminal _a3 to defective part _B3 of the source line 32. However, the other B _{3 is}
No signal is supplied to −d ₃ . The terminal a ₃ at one end of the source line 32 and the terminal b ₃ of the correction wiring 33 are connected, the source signal is taken out to the outside by an FPC 31, etc., and the correction signal is connected from the other side of the first board 11 by an FPC 31 etc. By connecting terminal c ₃ on the wiring and terminal d ₃ on the source line, the source signal can be connected to the disconnected part.
It is supplied to all source lines 32 except _B3 . Therefore, line defects can be removed and converted into point defects that are hardly recognizable on image display. The correction wiring 33 is arranged in parallel on the first substrate 11 on the outside of the source terminal h formation region and connects to the connection terminal k.
are formed, and the wiring f ₁ , g ₁ , f ₂ ,
It will be connected to g ₂ through this connection terminal k. By arranging the connection terminal k of the correction wiring 33 in parallel with the source terminal h and forming it on the edge of the first substrate 11 in this way, simultaneous connection with the source line 32 is possible. The metal wiring and correction wiring 33 are the same as before.
It can be formed from foil, vapor deposited film, plating film, printed layer, etc. of Al, Cu, Ni, Au, etc.

With the above configuration, (1) the terminals b 3 and _{c 3} of the correction wiring are formed in the immediate vicinity of the terminals a ₃ and d ₃ on the source line 32, and both terminals a ₃
Since both ~d _{and 3} are on the same surface of the same substrate, the length of the wire connection can be made very short, on the order of several hundred μm, and furthermore, since there are no steps, the wire connection can be made easily.

(2) Terminals a ₃ and d ₃ on source line 32 and correction wiring 3
Terminals b ₃ and c ₃ of No. 3 are formed on the same surface, and the distance can be specified in advance, making it possible to automate wiring connections and reduce costs.

(3) Correction wiring 33 Source line 3 of first substrate 11
By forming it on the same surface as 2, the connection terminal k can be provided on the same surface as the source line terminal h when the correction wiring is taken out to the outside, and it can be drawn out using the FPC 31 for drawing out the source line. Become.

(4) If the correction wiring width and line spacing are each several tens of μm, the wiring pitch is 100 to 200 μm, and even if 10 correction wirings 33 are formed, the correction wiring area is 1.
It only increases by ~2 mm, and the display panel hardly becomes larger.

(5) Since the correction wiring 33 is formed on the first substrate 11, it is formed on the third substrate 14 in FIG. 2 and in FIG.
PWB21 is no longer required, and the board attachment process and parts to fix PWB21 (not shown)
Since the number of parts can be reduced, costs can be reduced.

(6) Since the correction wiring 33 can be formed without increasing the normal display panel manufacturing process, it is possible to significantly reduce costs.

(7) By forming the correction wiring 33 on the display panel, defects discovered by electrical tests after the completion of the display panel manufacturing process can be corrected at any time after the liquid crystal is injected and sealed.

You can obtain excellent advantages such as:

Note that although the above description has been made regarding the source line, the same explanation can be applied to the gate line as well.

Further, although the description has been made using a liquid crystal as a display medium and a TFT as a switching element, there is no problem in using an electrochromic material as a display medium and a MOSFET, MIM, diode, etc. as a switching element.

<Effects of the Invention> As described above, by using the present invention, the line area where no signal is supplied, that is, the line defect, which occurs due to a defect in the wiring conductor, becomes a line defect with the connecting portions located on both sides of the correction wiring. By interconnecting the connecting points of the wiring conductors at the outer positions on the left and right sides of the display panel and constructing a new signal supply path using correction wiring, it is possible to supply signals, and it is possible to supply signals only to the defective parts. It will be converted into a point defect. Therefore, the yield of the display device is improved, and defects on the display panel can be easily corrected, and costs can be reduced. The number of line defects that occur in a display panel is generally on the order of a few lines or less at most, and the probability that two or more defective portions exist in one wiring conductor is extremely low. Therefore, the present invention can eliminate line defects very effectively by arranging wiring conductors with a small number of lines outside the display panel. It also works well and is suitable for mass production.
Its technical value is enormous.

[Brief explanation of the drawing]

FIG. 1 is a basic circuit diagram of an image display device using conventional switching elements. 2 and 3A and 3B are configuration diagrams showing the structure of a conventional display panel. FIG. 4A is a plan view of a liquid crystal display panel illustrating one embodiment of the present invention. FIG. 4B is a sectional view taken along line XX' in FIG. 4A. 11...first substrate, 12...second substrate, 3
1...FPC, 32... Source line, 33... Correction wiring, 34... Insulating layer.

Claims (1)

[Scope of Claims] 1. A display comprising a display panel in which a display driving wiring conductor extends from one edge of the display screen to the other edge and extends outside the display screen area, and in which a display medium is installed. In the apparatus, a correction wiring for correcting a defect in the wiring conductor is arranged outside the display panel, and the correction wiring has one side of the wiring conductor that passes through the display panel with the display screen in between. a first connection part connectable to the other end of the wiring conductor; the other side has a second connection part connectable to the other end of the wiring conductor; A display device comprising a signal supply path correction function that converts defects into point defects. 2. The display device according to claim 1, wherein the wiring conductors are formed in a matrix within the display screen area. 3. Claim 1 in which the vicinity of the end of the correction wiring is laminated in a direction intersecting the wiring conductor via an insulating layer.
Display device as described in section.