JP4393253B2 - Liquid crystal display device and manufacturing method thereof - Google Patents

Description

  The present invention relates to a liquid crystal display device having a chip-on-glass (COG) structure in which an LSI is mounted on a glass substrate, and in particular, a liquid crystal display capable of preventing malfunction caused by migration between signal wires for LSI control. The present invention relates to an apparatus and a manufacturing method thereof.

  Conventionally, a chip-on-glass (COG) type liquid crystal display panel in which a chip or LSI for driving a liquid crystal display panel is mounted on a glass substrate is known (see, for example, Patent Document 1). In the COG type liquid crystal display panel, since the LSI is directly mounted on the glass substrate, the structure can be simplified and the cost can be reduced.

  In the COG type liquid crystal display panel, generally, a plurality of LSIs are arranged on the control wiring (gate) driving side and the signal wiring (drain) driving side along the edge of the liquid crystal display region. And the signal wiring for controlling these LSI is provided on the glass substrate. A plurality of signal wirings for supplying input signals to the LSI are provided adjacently between the LSIs or between the LSIs and the printed wiring board.

  As a material for the signal wiring, aluminum (Al) with low resistance and low cost is generally used, and an aluminum wiring structure that prevents generation of hillocks and whiskers has been proposed (for example, Patent Document 2).

  FIG. 1 shows a conventional signal wiring pattern provided on a COG type liquid crystal display panel. LSI 101a and LSI 101b are arranged along an end portion of a liquid crystal display region (not shown), and signal wirings 105a, 105b and 105c for connecting them are formed at a predetermined interval.

  At this time, if there is a potential difference between two adjacent signal wirings, there is a disadvantage that the two wirings come into contact with each other due to migration. In FIG. 1, a migration 106 is generated between the signal wirings 105a and 105b.

The migration phenomenon means that when a current continues to flow through a metal wiring under specified conditions, the metal that forms the metal wiring moves on the insulator (migration), and the insulation resistance between the wirings significantly decreases, resulting in a failure. It is a phenomenon that arrives. A typical example of a failure is a short circuit.
Japanese Patent Laid-Open No. 7-5487 JP-A-5-31528

  When migration occurs, the signal wirings 105a and 105b are short-circuited, and the potential of each signal wiring changes. In the example of FIG. 1, the potential in the migration 106 is an intermediate potential between the signal wiring 105a and the signal wiring 105b. For this reason, a legitimate signal is not input to the LSI, causing a malfunction.

  In order to prevent migration between wirings, conventionally, the electric field between wirings has been reduced by widening the distance between two adjacent wirings. However, in this method, the area of the wiring portion is increased and the outer size of the glass substrate constituting the liquid crystal panel is increased. As a result, the size of the entire liquid crystal display module increases.

  Since the liquid crystal display panel is mounted on a notebook personal computer or a mobile phone, it is desired to make it as small as possible. On the other hand, it is necessary to avoid a malfunction between the two signal wirings by avoiding migration.

  Therefore, the present invention provides a liquid crystal display device that can prevent functional failures even if migration between metal wirings occurs without increasing the size of the liquid crystal display device.

  In addition, a method for manufacturing such a liquid crystal display device is provided.

  In order to realize the liquid crystal display device as described above, a conductor pattern that is not connected to the input of the LSI is disposed between adjacent signal wirings input to the LSI on the glass substrate. By inserting a conductor pattern between adjacent signal wirings, migration occurs toward the nearest conductor pattern. Even if one adjacent signal line and the conductor pattern are short-circuited, the signal potential of the other signal line is not affected. Further, migration does not affect the signal potential of the other signal wiring. Therefore, a regular control signal is input to the LSI in each signal wiring.

In one aspect of the present invention, a liquid crystal display device
(A) a glass substrate;
(B) a liquid crystal display unit formed in a predetermined region on the glass substrate;
(C) an LSI mounted on the glass substrate and driving the liquid crystal display unit;
(D) two or more signal wirings connected to the input of the LSI;
(E) A conductor pattern that is disposed along the signal wiring between the adjacent signal wirings and is not connected to the input of the LSI.

  As the conductor pattern, for example, an isolated pattern in which both ends are connected to nowhere, two or more parallel conductor patterns extending between adjacent signal wirings, and a plurality of island shapes arranged along the signal wiring between adjacent signal wirings As long as the pattern is divided from the input to the LSI, any shape can be adopted.

In another aspect of the present invention, a method for manufacturing a liquid crystal display device is provided. The manufacturing method of the liquid crystal display device is as follows:
(A) A matrix-shaped thin film transistor array is formed on a glass substrate, and a signal wiring extending to a predetermined position on the glass substrate and between the two adjacent signal wirings along the signal wiring. forming a conductor pattern which does not reach the predetermined position Te,
(B) forming a liquid crystal display on the thin film transistor array;
(C) mounting an LSI at the predetermined position.

  Even if migration occurs between the metal wires for LSI control as the device is used for a long time, the operation of the LSI can be properly maintained, and the inconvenience in function of the liquid crystal display panel can be avoided.

  FIG. 2 is a schematic plan view of a COG type liquid crystal display panel to which the present invention is applied. The COG type liquid crystal display panel 10 includes a TFT substrate 12 in which a thin transistor (TFT) array (not shown) is disposed on a glass substrate, and a liquid crystal layer (not shown) in a liquid crystal display (TFT-LCD) portion 15 of the liquid crystal display panel 10. ) With a color filter (CF) substrate 13 facing the TFT substrate 12 and a plurality of LSIs 11 arranged along the end of the liquid crystal display unit 15.

  The LSI 11 is connected to a connection terminal connected to a printed wiring board by interconnection with a signal wiring 16. In FIG. 2, the signal wiring 16 is illustrated as a single line for convenience, but may be composed of a plurality of metal wirings adjacent to each other. Although not shown, each LSI 11 has a data line connected to the drain of the TFT or a gate line connected to the gate of the TFT in order to drive the TFT constituting the liquid crystal display element of the liquid crystal display unit 15. It shall be extended.

  FIG. 3 is a diagram illustrating an example of a signal wiring pattern according to an embodiment of the present invention. Between the LSIs 11a and 11b, which are drive circuits for the liquid crystal display elements, signal wirings 21, 22, and 23 connected to the inputs of these LSIs are arranged. In addition, signal wirings 31, 32, and 33 connected to the input of the LSI 11b from an external circuit (not shown) are provided.

  A conductor pattern 26 is disposed between the signal lines 21 and 22, and a conductor pattern 27 is disposed between the signal lines 22 and 23. The conductor patterns 26 and 27 are independent patterns whose both ends are not connected anywhere. Since no voltage is supplied to the conductor patterns 26 and 27, the conductor patterns 26 and 27 are in a floating state.

  On the other hand, a conductor pattern 36 is disposed between the signal wirings 31 and 32, and a conductor pattern 37 is disposed between the signal wirings 32 and 33. One end sides of the conductor patterns 36 and 37 are disconnected without being connected anywhere. The other end side may be connected to a printed wiring board or the like, for example, or may be floating.

  The signal wirings 21 to 23 and the signal wirings 31 to 33 need only be formed with the conventional wiring width and wiring interval in the liquid crystal display panel, and it is not necessary to change the design in particular in order to apply the present invention.

  As an example, the line width is, for example, 100 μm, and they are arranged at an interval of 100 μm. The conductor patterns 26, 27, 36, and 37 have a pattern width of 20 μm, for example, and are arranged between two adjacent signal wirings.

  By inserting such a conductor pattern between adjacent signal wirings, it is possible to prevent LSI malfunctions due to migration without changing the conventional wiring design and without increasing the size of the liquid crystal display panel. Can do. This will be described with reference to FIG.

  FIG. 4 is a diagram for explaining migration in the signal wiring pattern of FIG. As the liquid crystal display panel 10 continues to be used, the signal wiring 21 and the conductor pattern 26 come into contact with each other due to the movement of the metal atoms constituting the signal wiring, and migration 28 occurs. The voltage applied to the signal wiring 21 is connected to the conductor pattern 26, but the conductor pattern 26 is disconnected from the LSIs 11a and 11b and is in a floating state. Therefore, no error signal is input from the conductor pattern 26 to the LSI 11a or 11b.

  Further, since no other voltage is applied to the signal wiring 21 and the signal wiring 22 electrically, only regular signals are input to the corresponding terminals of the LSIs 11a and 11b. As a result, even if migration occurs, the reliability of the liquid crystal display panel 10 can be maintained without affecting the operation of the LSIs 11a and 11b.

  5A to 5C are cross-sectional views taken along the line A-A ′ of FIG. 3. The arrangement examples of the signal wirings 21 and 22 and the conductor pattern 26 inserted between them in the stacking direction are shown.

  In FIG. 5A, all of the signal wirings 21 and 22 and the conductor pattern 26 are formed on the glass substrate 41. The signal wirings 21 and 22 and the conductor pattern 26 are the same steps as the formation of the gate electrode (not shown) of the TFT constituting the liquid crystal display element in the liquid crystal display (TFT-LCD) portion 15 and the control signal line connected thereto. At the same time. A structure in which aluminum (Al) or an Al—Nd alloy is laminated with titanium (Ti) or molybdenum (Mo), for example, an Al / Ti laminated layer or an AlNd / Mo laminated layer is adopted as the signal wirings 21 and 22 and the conductor pattern. Can do.

  The signal wirings 21 and 22 and the conductor pattern 26 are covered with insulating films 42 and 42.

  On the other hand, in the example shown in FIG. 5B, the conductor pattern 26 is formed in a layer different from the signal wirings 21 and 22. The signal wirings 21 and 22 are directly located on the glass substrate 41. The conductor pattern 26 is located above the signal wirings 21 and 22 via the insulating film 42 between the signal wirings 21 and 22. In this case, the pattern width of the conductor pattern is set so that the distance between the signal wiring 21 and the conductor pattern 26 is shorter than the distance between the signal wirings 21 and 22. Similarly, the distance between the signal wiring 22 and the conductor pattern 26 is set to be shorter than the distance between the signal wirings 21 and 22.

  5B, the signal lines 21 and 22 are formed in the same process as the gate electrode (not shown) of the TFT of the liquid crystal display unit 15 and the control signal line. The insulating film 42 covering the signal wirings 21 and 22 is formed in the same process as the gate insulating film formed on the gate electrode in the liquid crystal display unit 15. The conductor pattern 26 is formed in the same process as a TFT source electrode and drain electrode (not shown) of the liquid crystal display unit 15 and a signal line for supplying a scanning signal to the TFT.

  With such a configuration, even if the metal atoms constituting the signal wiring 21 move through the insulating film 42 due to the migration effect and come into contact with the nearest conductor pattern 26, the conductor pattern 26 is in a floating state. An error signal is never input. Further, since the signal wiring 21 is not affected by the potential of the other signal wirings 22, a normal signal is supplied from the signal wiring 21 to the input terminal of the corresponding LSI. Therefore, malfunction can be prevented.

  In the example shown in FIG. 5C, the conductor pattern 26 is formed directly on the glass substrate 41, and the signal wirings 21 and 22 are formed in an upper layer via the insulating film 42 with the conductor pattern 26 interposed therebetween. Also in this arrangement example, the pattern width of the conductor pattern is such that the distance between the signal wiring 21 and the conductor pattern 26 or the distance between the signal wiring 22 and the conductor pattern 26 is shorter than the distance between the two signal wirings 21 and 22. Set.

  The conductor pattern 26 is formed in the same process as the TFT gate electrode and the control signal line of the liquid crystal display unit 15. The insulating film 42 covering the conductor pattern 26 is formed in the same process as the gate insulating film formed on the gate electrode in the liquid crystal display unit 15. The upper signal wirings 21 and 22 are formed in the same process as the source and drain electrodes of the TFT of the liquid crystal display unit 15 and the signal line for supplying a scanning signal to the TFT.

  With such a configuration, the same effect as the configuration shown in FIGS. 5A and 5B can be achieved.

  FIG. 6 shows a modification of the conductor pattern shown in FIG. In the modification of FIG. 6, a plurality of conductor patterns that are not connected to the LSI input are arranged between two adjacent signal wires. For example, isolated conductor patterns 56 a and 56 b are arranged between the signal wirings 21 and 22, and independent conductor patterns 57 a and 57 b are arranged between the signal wirings 22 and 23. Similarly, between the signal wirings 31 and 32 and between the signal wirings 32 and 33, conductor pattern pairs 66a and 66b that are not connected to the LSI 11b and conductor pattern pairs 67a and 67b extend in parallel with each other.

  However, it is not necessary to use a plurality of conductor patterns arranged between all adjacent signal wirings, and it may be combined with an example in which one conductor pattern is inserted as shown in FIG.

  The plurality of conductor patterns 56a, 56b, 57a, 57b, 66a, 66b, 67a, 67b inserted between adjacent signal wirings may be formed in the same layer or in different layers. In any case, it is formed in the same process as the thin film transistor (TFT) of the liquid crystal display unit 15 without changing the arrangement configuration such as the line width and interval of the conventional signal wiring.

  In the configuration example of the conductor pattern of FIG. 6, even if migration 58a, 58b occurs from both the signal wirings 21 and 22 toward the conductor pattern between them, these migrations are performed in parallel in a floating state. It stops at the extending conductor patterns 56a and 56b. Therefore, contact of the signal wirings 21 and 22 input to the LSI 11 can be more effectively prevented. As a result, it is possible to prevent a change in the potential of the signal propagating through the signal wiring and improve the operation reliability of the liquid crystal display panel.

  The same applies to the signal lines 22 and 23, the signal lines 31 and 32, and the signal lines 32 and 33.

  FIG. 7 shows still another modification of the conductor pattern shown in FIG. In the modification of FIG. 7, a plurality of island-shaped conductor patterns are arranged along the direction of the signal wiring between two adjacent signal wirings. An island-shaped conductor pattern 76 is disposed between the signal wirings 21 and 22, and an island-shaped conductor pattern 77 extends between the signal wirings 22 and 22. Further, an island-shaped conductor pattern 86 is disposed between the signal wirings 31 and 32, and an island-shaped signal wiring 87 is disposed between the signal wirings 32 and 33.

  However, it is not necessary to configure the conductor pattern between all the signal wirings as an island pattern, and it may be combined with one conductor pattern shown in FIG. 3 or a plurality of conductor patterns shown in FIG.

  According to the configuration of FIG. 7, even if migration occurs from an arbitrary signal wiring input to the LSI 11a or 11b, it remains in local contact with the nearest island-shaped conductor pattern and affects the adjacent signal wiring. Can be prevented. Even if migration 78a, 78b occurs from both adjacent signal wirings 21, 22 toward the nearest island-shaped conductor pattern 76, each conductor pattern 76 is isolated in a floating state. Does not affect the signal potential.

  As described above, by inserting a conductor pattern that is not connected to an LSI input between adjacent signal wirings, malfunctions such as malfunctions can be prevented even if migration occurs.

Finally, the following notes are disclosed regarding the above description.
(Appendix 1) Glass substrate,
A liquid crystal display unit formed in a predetermined region on the glass substrate;
An LSI mounted on the glass substrate and driving the liquid crystal display unit;
Two or more signal wirings connected to the input of the LSI;
A liquid crystal display device comprising: a conductor pattern which is disposed between adjacent signal wirings and which is not connected to an input of the LSI.
(Supplementary note 2) The liquid crystal display device according to supplementary note 1, wherein the conductor pattern is an isolated pattern in which both ends are connected to nowhere.
(Supplementary note 3) The liquid crystal display device according to supplementary note 1 or 2, wherein the conductor pattern is composed of two or more parallel conductor patterns extending between the adjacent signal wirings.
(Supplementary Note 4) The liquid crystal display according to Supplementary Note 1 or 2, wherein the conductor pattern includes a plurality of island-like patterns arranged along the signal wiring between the adjacent signal wirings. apparatus.
(Additional remark 5) The said conductor pattern is located in the same layer as the said signal wiring, The liquid crystal display device in any one of Additional remark 1-4 characterized by the above-mentioned.
(Additional remark 6) The said conductor pattern is located in the layer different from the said signal wiring, The liquid crystal display device in any one of Additional remark 1-4 characterized by the above-mentioned.
(Supplementary note 7) The liquid crystal display device according to supplementary note 6, wherein a distance between the conductor pattern and an adjacent signal line is set smaller than a distance between the adjacent signal lines.
(Supplementary Note 8) A thin film transistor array in a matrix shape is formed on a glass substrate, and the signal wiring extending to a predetermined position on the glass substrate and the two adjacent signal wirings are positioned on the predetermined substrate. Forming a conductor pattern that does not reach the position of
Forming a liquid crystal display on the thin film transistor array;
A method of manufacturing a liquid crystal display device including a step of mounting an LSI at the predetermined position.
(Supplementary note 9) The method for manufacturing a liquid crystal display device according to supplementary note 8, wherein at least one of the signal wiring and the conductor pattern is formed in the same step as the formation of the gate electrode of the thin film transistor.
(Additional remark 10) The manufacturing method of the liquid crystal display device of Additional remark 8 or 9 characterized by forming the said conductor pattern as an isolated pattern in which the both ends are not connected anywhere.

It is a figure which shows the conventional signal wiring pattern of a COG type | mold liquid crystal display panel. 1 is a schematic plan view of a COG type liquid crystal display panel to which the present invention is applied. It is a figure which shows the signal wiring pattern on the COG type liquid crystal display panel which concerns on one Embodiment of this invention. It is a figure for demonstrating the electromigration which may generate | occur | produce with the signal wiring pattern of FIG. FIG. 4 is a cross-sectional view taken along the line A-A ′ of FIG. 3, illustrating an arrangement example of signal wirings and conductor patterns between the wirings. It is a figure which shows the modification of the signal wiring pattern on the COG type | mold liquid crystal display panel which concerns on one Embodiment of this invention. It is a figure which shows another modification of the signal wiring pattern on the COG type liquid crystal display panel which concerns on one Embodiment of this invention.

Explanation of symbols

10 Liquid crystal display panel (liquid crystal display device)
11, 11a, 11b LSI
12 TFT substrate 13 CF substrate 15 TFT-LCD (liquid crystal display)
16 Signal wiring 21, 22, 23, 31, 32, 33 Signal wiring 26, 27, 36, 37, 56a, 56b, 57a, 57b, 66a, 66b, 67a, 67b, 76, 77 connected to the input of the LSI 86, 87 Conductor patterns 28, 58a, 58b, 78a, 78b between the wires Migration 41 Glass substrate

Claims (5)

A glass substrate;
A liquid crystal display unit formed in a predetermined region on the glass substrate;
An LSI mounted on the glass substrate and driving the liquid crystal display unit;
Two or more signal wirings connected to the input of the LSI;
A liquid crystal display device comprising: a conductor pattern which is disposed along the signal wiring between the adjacent signal wirings and which is not connected to the input of the LSI.   The liquid crystal display device according to claim 1, wherein the conductive pattern is an isolated pattern in which both ends are not connected anywhere.   The liquid crystal display device according to claim 1, wherein the conductor pattern is composed of two or more parallel conductor patterns extending between the adjacent signal wirings.   3. The liquid crystal display device according to claim 1, wherein the conductor pattern includes a plurality of island-like patterns arranged along the signal wiring between the adjacent signal wirings. A matrix-shaped thin film transistor array is formed on the glass substrate, and the signal wiring extending to a predetermined position on the glass substrate and the two adjacent signal wirings along the signal wiring. Forming a conductor pattern that does not reach the position of
Forming a liquid crystal display on the thin film transistor array;
A method of manufacturing a liquid crystal display device including a step of mounting an LSI at the predetermined position.

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