JPH11194355A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve reliability of the electric connection of a liquid crystal display device where the pitch of an input terminal electrode group is not more than 70 μm by providing a wide part where an input terminal electrode exceeds the specified value of the pitch, setting the same part in an electrode adjacent to the electrode having the wide part on a side near a display part to be a narrow part and setting a minimum interval between the adjacent electrodes to more than a specified value. SOLUTION: An area sandwiched by a straight line 10 containing the edge of the display part side of the wide part 4 formed on the side near the display part and a straight line 11 containing the edge of the substrate end face side of the wide part 4 formed on a side near the substrate end face 9 of the adjacent electrode is an electric connection area by an anisotropic conductive connection means. The first 40-60% of the electric connection area, which is viewed from the display part side, by the anisotropic conductive connection means is the wide part, the first same part of the other input terminal electrode is the narrow part and the remaining part is the wide part. The interval between the straight lines 10 and 11 is set so that the minimum interval between the adjacent electrodes satisfies the condition of not less than 25 μm.

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 liquid crystal display panel having a TC.
The present invention relates to a liquid crystal display device in which a P-type driving LSI is electrically connected via anisotropic conductive connection means.

[0002]

2. Description of the Related Art With the increase in the number of display electrodes corresponding to higher definition and colorization of the screen of a liquid crystal display panel, the number of input terminal electrodes for supplying display signals to the display electrodes increases, and therefore the pitch of the input terminal electrodes Needs to be narrowed.

Conventionally, as a shape of an input terminal electrode group of a liquid crystal display panel, a transparent electrode having a constant line width is arranged in parallel with a certain interval (line distance) for ensuring insulation from an adjacent electrode. Was common.

However, according to such a method, when the pitch of the input terminal electrode group is reduced, the relative positional relationship between the input terminal electrode group and the output side electrode group of the TCP type driving LSI is remarkably affected, and one pitch Even if the measures of making the line width slightly larger and reducing the distance between the lines by that amount are incorporated, for example, when the pitch is 60 μm, the pitch is 20 μm.
With a slight deviation, the probability of occurrence of poor electrical connection (disconnection) between the two electrode groups and contact with adjacent electrodes is significantly increased, so that the reliability of the electrical connection is reduced and the yield is greatly reduced. there were.

[0005] Here, the relative deviation of the positional relationship between the two electrode groups is caused by various processing errors and work errors that occur at the time of component production and assembly, for example, variations at the time of etching the copper lead of the TCP type LSI. Line width thinning error, mechanically at the time of initial alignment under normal temperature atmosphere via anisotropic conductive connection means between input terminal electrode group of liquid crystal display panel and output side electrode group of TCP type driving LSI In addition, a displacement error or the like generated due to a difference in thermal expansion coefficient during thermocompression bonding is caused by cumulative addition.

In order to reduce such a deviation, there is a concept of minimizing individual errors that cause such deviation. For example, it is necessary to introduce a precise mounter device only by minimizing the initial alignment accuracy. As a whole, not only a huge equipment is required, but also a reduction in yield in each process is unavoidable, and the pitch applicable to mass production technology is 70 μm.
To the extent that is the limit.

[0007]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems and improves the reliability of electrical connection of a liquid crystal display device in which the pitch of input terminal electrode groups is 70 μm or less, with an increase in equipment load. It is intended to improve without any improvement.

[0008]

The anisotropic conductive connection means used for electrical connection between the input terminal electrode group of the liquid crystal display panel and the output side electrode group of the TCP type driving LSI includes metal microspheres or Anisotropic conductive film formed into a film by uniformly dispersing microspheres imparting conductivity such as metal-plated plastic microspheres in a thermoplastic or thermosetting resin that becomes solid at room temperature, Alternatively, an anisotropic conductive liquid adhesive resin in which similar microspheres are dispersed in a liquid thermosetting resin at room temperature is exemplified.

These are interposed between the input terminal electrode group of the opposed liquid crystal display panel and the output side electrode group of the TCP type driving LSI, and are heated and pressurized so as to be present between the corresponding electrodes. The microsphere is compressed, and conduction between both electrodes is achieved via the microsphere.

The number of microspheres existing between the two electrodes is proportional to the overlapping area of the two electrodes if the concentration in the anisotropic conductive connecting means is constant. The overlap width of both electrodes greatly affects the number of microspheres contributing to the above. In the case of a normal anisotropic conductive film in which microspheres having an average particle size of about 5 to 6 μm are dispersed, the overlap width is small. When the thickness is less than 10 μm, the reliability of the electrical connection is extremely reduced.

According to the present invention, the extremely low reliability of the electrical connection between the input terminal electrode of the liquid crystal display panel and the output side electrode of the TCP type driving LSI via the anisotropic conductive connection means is extremely reduced.
Focusing on the fact that the overlap width rather than the overlap area of the two electrodes has a large effect as described above, we have conducted extensive research on the terminal shape that maintains a large overlap width even if a relative displacement occurs between the two electrodes. It has been completed and is as follows.

[1] One of the two substrates sandwiching the liquid crystal substance is bonded so as to protrude from the other, and an electrode group mainly composed of input terminal electrodes for electrical connection is formed at the protruding portion. In the liquid crystal display device, the output side electrode group of the TCP type driving LSI is electrically connected via anisotropic conductive connection means, the pitch of the input terminal electrodes is 70 μm or less, and each input terminal electrode Each has a wide portion exceeding 60% of the pitch, and an electrode adjacent to an electrode having a wide portion on the side closer to the display portion in the electrical connection region by the anisotropic conductive connection means has the same portion as the narrow portion. And a minimum gap between adjacent electrodes is 25 μm or more.

[2] Two adjacent input terminal electrodes are paired, and the first four input terminal electrodes are the first four when viewed from the display portion side of the electrical connection region by the anisotropic conductive connection means.
The liquid crystal display device according to [1], wherein 0% to 60% is a wide portion, and the other input terminal electrode has a narrow portion at the beginning and a wide portion at the beginning.

[3] A display part of an electrical connection region of the first and third input terminal electrodes formed by the anisotropic conductive connection means, wherein three continuous input terminal electrodes form a set. When viewed from the side, the first 50% to 75% is a wide portion, and the second input terminal electrode is the first pattern in which the same portion at the beginning is a narrow portion and the rest is a wide portion,
Conversely, the first 25% to 5% of the first and third input terminal electrodes
0% is a narrow portion and the rest is a wide portion, and the second input terminal electrode has a wide portion at the beginning of the same portion.
The liquid crystal display device according to [1], wherein the liquid crystal display device is any one of the patterns described above.

[4] The liquid crystal display device of [3], wherein the width of the wide portion of the second input terminal electrode in the first pattern and the second pattern is 100% or more of the pitch.

[5] The length of the wide portion of the first and third input terminal electrodes in the first pattern and the second pattern is 6 times the length of the input terminal electrode in the electrical connection region.
The liquid crystal display device according to [3] or [4], which has 0% to 70%.

[6] The liquid crystal display device of [3], [4] or [5], wherein the first pattern and the second pattern are alternately repeated.

[7] The width of the wide portion of the output side electrode of the TCP type driving LSI is smaller by 5 to 20 μm than the width of the wide portion of the input terminal electrode of the corresponding liquid crystal display panel. 4, 5, or 6 liquid crystal display devices.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a large overlapping width is maintained even if a relative displacement occurs between an input terminal electrode of a liquid crystal display panel and an output electrode of a TCP type driving LSI. In order to achieve this, it is important that each input terminal electrode has a wide portion that exceeds 60%, preferably more than 75%, of the pitch.

The pitch of the input terminal electrodes is 70 μm or less, and the minimum gap between adjacent electrodes is 2 mm for insulation.
In order to satisfy the above requirements while keeping the thickness at 5 μm or more, the same portion of the electrode adjacent to the electrode having the wide portion on the side close to the display portion in the electrical connection region by the anisotropic conductive connection means is set to the narrow portion. You.

The wide portion mainly serves for electrical connection to the output side electrode of the driving LSI, and the narrow portion mainly serves for conduction to the display electrode. Varying the width in the direction and separating the functions results in improved reliability of the electrical connection.

Here, the width of the narrow portion is 40% of the pitch width.
If the distance between adjacent electrodes is constant, the width of the wide portion can be increased as the ratio is reduced, but from the viewpoint of the stability of the etching step, etc.
It is preferable to leave a width of the order.

In one preferred embodiment of the present invention,
Two adjacent input terminal electrodes form a pair, and the first 40% to 60% of the first input terminal electrode is a wide portion when viewed from the display portion side of the electrical connection area by the anisotropic conductive connection means. In the other input terminal electrode, the same portion at the beginning is a narrow portion and the rest is a wide portion.

FIG. 1 shows an embodiment of the present invention, and is an enlarged plan view of a main part of an input terminal portion of a liquid crystal display panel. In FIG. 1, as in the case of the figures showing other terminal electrode shapes, for the sake of explanation, the magnification in the horizontal direction is further enlarged to about 20 times that in the vertical direction.

In the figure, a portion extending from the boundary 1 on the display portion side to the substrate end surface 9 is an input terminal portion. Of these, the lead portion 2 from the display portion side and the C-plane processing for cutting off the corner of the substrate end surface are applied. Region 8 and regions excluding regions 3 and 6 adjacent thereto, that is, a straight line 10 including the edge of the wide portion 4 formed on the side closer to the display portion on the display portion side, and a substrate end surface 9 of the adjacent electrode. The region between the straight portion 11 and the edge of the wide portion 4 formed on the side closer to the substrate end surface is the electrical connection region by the anisotropic conductive connection means.

In FIG. 1, the center line of the wide portion 4 and the center line of the narrow portion 5 are aligned, and in order to maintain a constant pitch,
Although the entire input terminal group has an alternating pattern, if the center lines of the two are shifted as shown in FIG. 2, the degree of freedom of the combination pattern is increased, and the size can be reduced at both ends of the electrode group.

In FIG. 1, a narrow portion 5 is provided in front of an electrode having a wide portion 4 on the side close to the display section for convenience of inspection. As shown in FIG. 3, only the narrow part on the display part side which conducts to the display part may be left, and the narrow part on the end face side of the substrate may be omitted.

Here, a straight line including the edge of the wide portion 4 formed on the side closer to the display portion and farther from the display portion, and the substrate of the wide portion 4 formed on the side closer to the substrate end surface 9 of the adjacent electrode. The gap with the straight line including the edge farther from the end face is set so that at least the minimum gap between the adjacent electrodes satisfies the requirement of 25 μm or more, but may be set as large as about 50 μm to 300 μm. .

However, if the width is too large, a critical decrease in the superposed width of both electrodes at the time of electrical connection with the output side electrode of the TCP type driving LSI via the anisotropic conductive connection means will occur. Are not connected, but are disadvantageous because the overlapping area is too small.

In these two pairs, the lengths and widths of the wide portions of both input terminal electrodes are set to be substantially equal to each other, depending on the position relative to the output side electrode of the TCP type driving LSI. It is preferable that the overlap width and the overlap area of the respective electrodes are maintained even when the displacement occurs.

In another preferred embodiment of the present invention, three consecutive input terminal electrodes form a set, and the combination is formed of the first and third input terminal electrodes by the anisotropic conductive means. The first 50% to 75%, and preferably 60% to 70%, of the first connection terminal electrode when viewed from the display portion side is a wide portion. The first pattern, which is a wide portion, or conversely, the first 25% of the first and third input terminal electrodes
５０50%, preferably 30 %％ 40%, the narrow portion and the remaining portion are the wide portion, and the second input terminal electrode is in any one of the second patterns in which the same portion as the first portion is the wide portion. Has become.

FIG. 4 shows one embodiment of the present invention, in which 12 surrounded by a broken line indicates a first pattern, and 13 indicates a second pattern. In this embodiment, the width of the wide portion of the second input terminal electrode can be set to be about twice as large as those of the first and third electrodes, and can be set to 100% or more of the pitch width. Become.

In this case, the length of the wide portion of the second input terminal electrode is １ ／ of those of the first and third electrodes.
By this, the area of the wide portion of each terminal electrode that contributes to the electrical connection is made large and uniform, and even if there is a shift, the area of the portion that contributes to the electrical connection of each electrode is made uniform. It is possible to secure a large relationship while maintaining a certain relationship.

In this set of three, as shown in FIG. 4, alternately arranging the first pattern and the second pattern makes it possible to inspect the disconnection and short circuit of the display electrode of the liquid crystal display panel. It is preferable from the viewpoint.

That is, with such an arrangement, FIG.
The input terminal electrodes having wide portions on the side close to the end face of the substrate are lined up every other as shown in the figure, and this wide portion is connected in common without applying extra external leads, and voltage is applied thereto. Then, in the normal part, it lights every other line, if there is a short-circuit with the adjacent electrode, it lights three consecutively there, and if there is a disconnection, it turns off three consecutive lights in that part. In addition, the simplicity and reliability of the inspection are increased, and the input terminal pattern can be simplified.
It is possible to reduce the probability of occurrence of a poor electrical connection with the output side electrode of the mold driving LSI.

In the present invention, the entirety of the input terminal electrode group of the liquid crystal display panel is formed by combining a pair of two unit patterns or a set of three first unit patterns, a second unit pattern, and an alternate pattern thereof. In general, a repetitive regular pattern is used, but the entire pattern is formed by appropriately combining different types of unit patterns for the purpose of giving a relationship with the pattern of the display electrode and the lead-out electrode or for imparting distinctiveness. You can also.

In the case of the above-mentioned regular pattern, for example, when the set of three first unit patterns is repeated, and the total number of required input terminal electrodes does not become a multiple of three, Alternatively, the termination may be completed in the middle of the unit pattern, or the dummy electrodes constituting the electrode group together with the input terminal electrodes may be mainly incorporated in the unit patterns at both ends to complete the operation.

Here, the dummy electrode is used to increase the certainty of the conductive connection by making the crimping force applied to each input terminal electrode uniform,
For the main purpose of adjusting the mismatch between the required number of input terminal electrodes and the number of output electrodes of the TCP LSI, a plurality of input terminals are provided at both ends of the input terminal of the liquid crystal display panel and the output electrodes of the TCP LSI. It is something that can be done.

In the present invention, as in the conventional case, the input terminal group having the above-mentioned shape comprises a transparent conductive film made of indium tin oxide or the like formed on a transparent substrate, together with a display electrode and a routing electrode. It can be formed by a method such as patterning by a photolithography method, and does not require any increase in equipment load when implementing the present invention.

While the input terminal group of the liquid crystal display panel has been mainly described above, the shape of the output side electrode group of one TCP type LSI is such that when both electrode surfaces are opposed to each other and overlapped, In a state where there is no displacement, the center of the wide portion of each corresponding electrode coincides with each other, and the wide portion of the output electrode of the LSI does not protrude from that of the input terminal electrode of the panel. It is preferable to make it 20 μm smaller.

By doing so, when the relative position between the input terminal electrode of the panel and the input terminal electrode is shifted, the change of the overlap width and the overlap area of each electrode can be reduced, and the overlap width of 10 μm can be reduced. It is possible to increase the allowable width of the shift until the occurrence of disconnection, which increases when broken, and the occurrence of short-circuiting due to approach to an adjacent electrode.

The position generated based on the difference in the coefficient of thermal expansion between the input terminal electrode group of the liquid crystal display panel and the output electrode group of the TCP type driving LSI at the time of thermocompression bonding via the anisotropic conductive connection means. It is also possible to use a contrivance such as previously increasing the pitch of the former at room temperature relatively by an amount corresponding to the deviation error.

[0043]

Hereinafter, the present invention will be described in more detail with reference to more specific examples. The patterns of the input terminal electrodes of the liquid crystal display panel are three types shown in FIGS. 5A, 5B, and 5C, the length of the electrical connection region is 2000 μm, the pitch of the input terminal electrodes is 60 μm, and FIG. ), The length of the wide portions of the first and third electrodes in (c) is 1350 μm, that of the second electrode is 550 μm, and the TCP type driving corresponding to each input terminal electrode is performed. The width of the wide portion of the output side electrode of the LSI for use was set to be 10 μm smaller than that of each input terminal electrode.

The pattern (a) is a comparative example in which the width of each conventional input terminal electrode is constant, and the patterns (b) and (c) both have the width of each input terminal electrode changing in the length direction. This corresponds to an embodiment of the present invention, and the pattern (b) is an example of a pair of two, and the pattern (c) is an example of a set of three. FIG.
In FIG. 2, only the pattern of the electrical connection region is shown to avoid complication.

Example 1 Minimum gap between adjacent electrodes is 25 μm
, The width of the wide part of each pattern, and
Table 1 below summarizes the relationship between the amount of lateral displacement between the two electrodes and the overlap width and overlap area.

[0046]

[Table 1]

As can be seen from Table 1, in the case of the conventional pattern (a) having no change in width, the deviation amount is 20 μm and the superimposition width is 10 μm, which is a risk of disconnection. In the case of the patterns (b) and (c) in which the width is changed, when the shift amount is 20 μm, the minimum is 2 μm.
A superimposed width of 2.5 μm and a superimposed area of 30325 square μm are ensured. Further, even if the deviation amount becomes 22.5 μm, a superimposed width of 17.5 μm and a superimposed area of 23625 square μm remain at least. It is evident that the tolerance for deviation has increased and the reliability of the electrical connection has been improved.

Example 2 Minimum gap between adjacent electrodes is 30 μm
, The width of the wide part of each pattern, and
Table 2 below summarizes the relationship between the amount of lateral displacement between the two electrodes, the overlap width, and the overlap area.

[0049]

[Table 2]

As can be seen from Table 2, in the case of the conventional pattern (a) having no change in width, the shift amount is 15 μm and the superimposition width is 10 μm, which is a risk of disconnection. In the case of the patterns (b) and (c) in which the width is changed, when the shift amount is 20 μm, the minimum is 15 μm.
In this case, the overlap width of 20 μm and the overlap area of 20250 square μm are secured. In this case as well, the allowable width of the shift is increased, and the reliability of the electrical connection is improved. Even if the shift amount further increases to 25 μm, a superimposition width of 20 μm and a superimposition area of 19000 square μm remain, and it is apparent that the improvement effect is remarkable.

[0051]

According to the present invention, the displacement of the input terminal electrode at the time of electrical connection between the liquid crystal display panel and the TCP type driving LSI via the anisotropic conductive connection means is as small as 70 μm or less. The tolerance is increased, and the reliability of the liquid crystal display device can be improved without increasing the facility load.

Further, in a mode in which two types of unit patterns of a set of three input terminal electrodes are alternately arranged, the simplicity and reliability of the inspection of the liquid crystal display panel are increased.

[Brief description of the drawings]

FIG. 1 is an enlarged plan view of a main part of an input terminal portion of a liquid crystal display panel according to one embodiment of the present invention.

FIG. 2 is an enlarged plan view of a main part of an input terminal portion of the liquid crystal display panel according to one embodiment of the present invention.

FIG. 3 is an enlarged plan view of a main part of an input terminal portion of the liquid crystal display panel according to one embodiment of the present invention.

FIG. 4 is an enlarged plan view of a main part of an input terminal portion of the liquid crystal display panel according to one embodiment of the present invention.

FIG. 5A is an enlarged plan view of a main part showing a shape of an input terminal electrode of an existing liquid crystal display panel in an electrical connection region.
(B), (c) The principal part enlarged plan view which shows the shape in the electrical connection area of the input terminal electrode of the liquid crystal display panel of this invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Boundary part of input terminal part on display part 2 Leading part from display part 4 Wide part of input terminal electrode 5 Same narrow part 8 C-plane processing area 9 Board end face 10 Display part side boundary of electrical connection area 11 Same board end face Side boundary 12 A set of three first patterns 13 A second pattern.

Claims (7)

[Claims] 1. One of two substrates sandwiching a liquid crystal substance is pasted so as to protrude from the other, and an electrode group mainly composed of an input terminal electrode for electrical connection is formed at the protruding portion. In a liquid crystal display device in which an output-side electrode group of a TCP-type driving LSI is electrically connected via anisotropic conductive connection means, a pitch of the input terminal electrodes is 70 μm or less, and each input terminal electrode is Each of the electrodes adjacent to the electrode having a wide portion exceeding 60% of the pitch and having the wide portion on the side closer to the display portion in the electrical connection region by the anisotropic conductive connection means has the same portion as the narrow portion. And a minimum gap between adjacent electrodes is 25 μm or more. 2. Two adjacent input terminal electrodes are paired, and the first 40% of one input terminal electrode is viewed from the display portion side of the electrical connection region by the anisotropic conductive connection means when viewed from the display portion side.
2. The liquid crystal display device according to claim 1, wherein a wide portion accounts for about 60%, and the other input terminal electrode has a narrow portion at the beginning and a wide portion at the rest. 3. A set of three consecutive input terminal electrodes, the combination being formed from the display portion side of the first and third input terminal electrodes in the electrical connection region by the anisotropic conductive means. The first 50% to 75% is the wide part,
The second input terminal electrode has a first pattern in which the same portion at the beginning is a narrow portion and the remaining portion is a wide portion, or conversely, the first 25% to 50% of the first and third input terminal electrodes are 2. The liquid crystal display device according to claim 1, wherein the remaining portion is a wide portion with a narrow portion, and the second input terminal electrode is one of the second patterns in which the same portion as the first portion is a wide portion. 4. The liquid crystal display device according to claim 3, wherein the width of the wide portion of the second input terminal electrode in the first pattern and the second pattern is 100% or more of the pitch. 5. The length of the wide portion of the first and third input terminal electrodes in the first pattern and the second pattern is 60% of the length of the input terminal electrode in the electrical connection region.
The liquid crystal display device according to claim 3, wherein the ratio is about 70%. 6. The liquid crystal display device according to claim 3, wherein the first pattern and the second pattern are alternately repeated. 7. The method according to claim 1, wherein the width of the wide part of the output side electrode of the TCP type driving LSI is smaller than that of the corresponding wide part of the input terminal electrode of the liquid crystal display panel by 5 to 20 μm.
2, 3, 4, 5 or 6 liquid crystal display devices.