JP2638197B2 - Connection structure between electrode terminal rows - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] The present invention relates to a connection structure between electrode terminal rows, and aims at improving the stability, reliability and yield of a connection by a conductive film between high-density terminal rows having a small electrode terminal width and electrode pitch. A device terminal portion having an electrode terminal line arranged in parallel, and a cable terminal portion having an electrode terminal line also arranged in parallel at the same pitch as the electrode terminal line of the terminal portion, so that both electrode terminal lines overlap. In the connection structure between the electrode terminal rows, which face each other, press the conductive film between them, press them with heat, and bond them by heating, the electrode widths (w ₁ , w ₂ ) of the respective electrode terminal rows of the device terminal section and the cable terminal section are determined. The sum (w ₁ + w ₂ ) is larger than the electrode pitch (p), and the gap between the electrode terminal rows is made equal in the short-mode and open-mode misalignment margins due to the misalignment (δ) between the center of both electrode terminals. Configure connection structure That.

[Industrial applications]

The present invention relates to an improvement in a connection structure between a device-side electrode panel having a high-density electrode terminal row and a flat cable having a high-density electrode terminal row.

In recent years, the development of display devices has been remarkable, and in particular, flat displays have rapidly spread in terms of thinness and light weight. Above all, liquid crystal display devices have low drive voltage and are inexpensive, and therefore are actively introduced into OA equipment fields such as personal computers and word processors.

Since liquid crystal display panels used for these applications are required to display characters and graphics, they are inevitably moving toward larger screens, more pixels, and higher definition. Has reached several hundreds, and the connection with the cable to connect to the drive circuit is extremely delicate, and it is becoming increasingly important in terms of quality and price.

[Conventional technology]

In general, a liquid crystal display device has a stripe-shaped transparent electrode (ITO: In ₂ O ₃ —SnO ₂ ) formed on _two glass panels, with both electrode surfaces facing each other, and perpendicular to each other, with an interval of about 10 μm. And stick them together. When a liquid crystal is injected into a gap formed by the two glass panels and a voltage is applied,
Due to the electro-optic effect of the liquid crystal or the like, the intersection of the two striped electrodes constitutes a pixel, and light and dark display is performed.

FIG. 4 is a view showing a conventional example of a connection structure between electrode terminal rows. FIG. 4A is a plan view, and FIG. 4B is a cross-sectional view along AA '. In the figure, reference numeral 10 denotes a liquid crystal device electrode panel portion, for example, a transparent glass plate having a size of 200 mm × 300 mm and a thickness of 1.1 mm, and 10a to 10g denoting stripe-shaped transparent electrodes (ITO) having a width of 0.27 mm, for example. The thickness is 100 nm, the distance between adjacent electrodes is 0.03 mm, that is, the pitch (p) between the electrodes is 0.3 mm.
Reference numeral 1 denotes a device terminal portion formed at the end of the stripe-shaped transparent electrode (ITO). In this example, the pitch is equal to that of the stripe-shaped transparent electrodes 10a to 10g, the width is 0.15 mm, and the space is 0.15 mm.
0.15mm line / space equidistant equipment terminal electrode row 1a
~ 1g.

20 is a so-called TAB cable (Tape Automated Bond
ng) is a kind of printed wiring board in which many conductor wirings are provided on a flexible thin resin board. Reference numeral 2 denotes a cable terminal portion. At the end of the TAB cable, cable terminal portion electrode rows 2a to 2g formed at the same width and at the same intervals as the device terminal portion electrode rows 1a to 1g are provided. 100 is a driver IC mounted on a TAB cable for driving a liquid crystal display panel.

Reference numeral 3 denotes a conductive film, which is a resin which functions as an adhesive, for example, a thermoplastic or semi-thermosetting resin, which is mixed with conductive particles, for example, Ni having a particle size of about 10 μm, and has a thickness of 0.01 to 0.05 mm.
This is a so-called anisotropic conductive film, which is electrically conductive in the film thickness direction when heated and pressed by being sandwiched between metal electrodes, but maintains insulation in the film surface direction.

That is, as shown in FIG. 2B, the cable terminal portion 2 of the TAB cable 20 is connected to the device terminal portion 1 of the liquid crystal device electrode panel portion 100 with the same conductive film 3 interposed therebetween, and the respective electrode rows 1a to 1g.
And 2a to 2g are overlapped so that they match, for example,
When heated and pressed at 150 ° C. and 20 kg / cm ² , the device terminal portion 1 and the cable terminal portion 2 are electrically connected via the metal particles 30 and mechanically bonded and fixed.

[Problems to be solved by the invention]

However, the electrode width of each of the electrode terminal rows is as narrow as 0.15 mm, and further, the electrode width tends to be further reduced due to the demand for higher definition of display and the demand for colorization in the future. Therefore, it is difficult to ideally connect the two electrode terminal rows as shown in the cross-sectional view of FIG.

FIG. 3 is a diagram showing the occurrence of a connection failure due to a displacement of the electrode terminal row. FIG. 3A shows an open mode in which the connection failure is open, and FIG. 3B shows a short mode in which the connection failure is short-circuited. FIG. For example, when the cable terminal portion 2 is displaced to the right in FIG. 1A, some of the electrode terminal row pairs have no metal particles interposed. Such a state is shown between 1b and 2b and between 1d and 2d, and conduction failure occurs in each electrode pair. In the case of the short mode shown in FIG. 2B, the positional deviation between the two electrode terminal rows is further increased, and the electrodes 2b and 2c of the electrode terminal rows of the cable terminal section 2 are made of metal particles 30 and the electrode terminals of the apparatus terminal section 1. A short-circuit failure occurs in which a short-circuit occurs via the electrode 1b in the column.

In the case of a display device, there is a serious problem that even if there is only one defective portion, the entire display panel will be defective.

[Means for solving the problem]

The above-mentioned object is to provide a device terminal section 1 having an electrode terminal row arranged in parallel and a cable terminal section 2 having an electrode terminal row also arranged in parallel at the same pitch as the electrode terminal row of the terminal section 1. In the connection structure between the electrode terminal rows which are opposed to each other so that the electrode terminal rows are overlapped, pressed and heated and bonded with the conductive film 3 interposed therebetween, the respective electrode terminal rows of the device terminal portion 1 and the cable terminal portion 2 are connected. (W ₁ , w ₂ )
₁ + w ₂ ) is larger than the electrode pitch (p), and the displacement margins in the short mode and the open mode due to the displacement (δ) between the center of both electrode terminals are made equal. This can be solved by a connection structure between the terminal rows.

[Action]

The connection between the two electrode terminal rows by the anisotropic conductive film 3 is as follows.
Since it is carried out through the metal particles 30 in the anisotropic conductive film 3, it depends on the particle diameter of the metal particles. I have. Therefore, the relationship between the degree of overlap between the upper and lower electrodes and the size of the metal particles affects the connection characteristics.

FIG. 1 is a view for explaining the principle of the present invention, wherein 1 is a device terminal portion, 2 is a cable terminal portion, 1a and 1b are device terminal portion electrode rows,
2a~2d the cable terminal electrode array, w ₁ is the electrode width of the device terminal portion electrode array, the electrode width of w ₂ is cable terminal electrode array, p is the two electrodes column electrode terminal pitch, [delta] is both electrode rows The displacement between the electrode centers, x is the overlap of the upper and lower electrodes, and y is the distance between the adjacent and opposing electrodes of the upper and lower electrode rows.

When the area where the open mode and the short mode do not occur is calculated from the above conditions, the result is as follows.

(A) When open mode _{x = w 1/2 + w} 2/2-δ ... (1) From the amount of overlap of the x ₀ to the open mode,
Conditions that do not open because the x> x _0, the region does not become open, i.e., the open mode margin delta _a is given by the following equation.

_{Δ a <1/2 (w 1 +} w 2) -x 0 ... (2) (b) short mode _{y = p-δ-w 1} /2 + w 2/2 ... (3) a short mode lowest electrode gap y _If it is set to ₀ , the condition that does not cause a short circuit is y> y _{0, and} therefore, the area that does not cause a short circuit, that is, the short mode margin Δ
_b is given by the following equation.

Δ _b <1/2 (w ₁ + w ₂ ) + p−y ₀ (4) FIG. 2 is a diagram for explaining the connection margin of the present invention, and the vertical axis represents the displacement (δ) of the upper and lower electrode terminal rows. The horizontal axis is the sum of the electrode widths of the upper and lower electrode terminal rows (w ₁ + w ₂ ). In the figure, in the case straight connection open mode placed the x = x ₀ in the formula (1), an open generating region the upper left portion across the straight line,
Connection good area lower right portion, i.e., represents the open mode margin delta _a.

On the other hand, the straight line in the short mode is represented by y =
If you place a y _0, the short generation region is the upper right portion across the straight line, connecting good area left lower portion, i.e., represents a short mode margin delta _b.

Intersection of two straight lines open mode margin delta _a the short mode margin delta _b are equal, that is, overall margin becomes maximum condition of the electrode connection, the sum of the electrode width to provide an intersection of the two straight lines and w _0, the formula From (1) and (3), w ₀ = p + (x ₀ −x ₀ ) (5) Since x ₀ > y ₀ is usually satisfied, the sum of the electrode widths (w ₁ +
w ₂ ) is larger than the electrode pitch p.

That is, according to the method of the present invention, it is possible to realize a connection structure in which a maximum connection margin can be obtained more reasonably than the conventional connection structure between electrode terminal rows having an equal electrode width and an equal interval. .

〔Example〕

The size of the liquid crystal device electrode panel 10 is 200 mm x 300
mm, a transparent glass plate with a thickness of 1.1 mm, on which In ₂
A striped transparent electrode (ITO) made of a mixed oxide of O ₃ -SnO ₂ was formed.

The electrode pitch of the device terminal electrode row formed at the end is two types of 200 μm and 100 μm, and the electrode terminal width (w ₁ ) and the space between electrodes (s ₁ ) are changed by three types, respectively, a total of six types. A sample of the liquid crystal panel terminal section was prepared.

On the other hand, TAB cable (Tape Automated Bonding) 20
Has two electrode pitches of 200 μm and 100 μm, and has an electrode width (w ₂ ) different from the electrode row of the device terminal section.
A total of six types of TAB cable terminal samples were prepared, each with three types of space between electrodes (s ₂ ).

As the anisotropic conductive film 3, conductive particles, for example, having a particle size of about 10 μm are contained in a semi-thermosetting resin serving as an adhesive.
Ni was mixed and used in the form of a film having a thickness of 15 μm. This was sandwiched between the two electrode terminals, and the electrodes were overlapped so that the respective electrode lines coincided with each other.
A pressure of ² cm ² was applied and heated and pressed for 20 seconds to bond.

Thus, the open, short, and connection resistance of the permanent sample was measured.

Table 1 is a table showing samples and measurement data of the examples of the present invention.

In the table, sample numbers * 1 and * 4 have the same electrode line width and space, that is, data in the case of the prior art.

On the other hand, sample numbers * 2, * 3, * 5, and * 6 show data when the connection structure according to the method of the present invention is employed. That is, both the sum of the electrode width of (w ₁ + w ₂₎ Yes made larger than the electrode pitch p, and the electrode width as the open mode margin delta _a the short mode margin delta _a equals w ₁ and w ₂ Is set.

As a result, the total margin Δ is
In each case, the improvement was 30%, which was a large improvement.

In the present embodiment, the case of the electrical connection between the electrode terminal example of the terminal portion of the liquid crystal display panel and the electrode terminal row of the TAB cable terminal portion has been described, but the present invention is not limited to this, and the same applies. Needless to say, the present invention can be applied to a connection structure of another product performed for the purpose.

〔The invention's effect〕

As described above, according to the present invention, as the open mode margin delta _a the short mode margin delta _b is equal and have set the electrode width w ₁ and w _2, overall margin of electrode connections greatly Therefore, for example, it greatly contributes to the improvement of the quality and reliability of the electrical connection between the terminal portion of the liquid crystal display panel and the TAB cable terminal portion and the improvement of the product yield.

[Brief description of the drawings]

FIG. 1 is a view for explaining the principle of the present invention, FIG. 2 is a view for explaining a connection margin of the present invention, FIG. 3 is a view showing a state of occurrence of a connection failure due to a displacement of an electrode terminal row, and FIG. FIG. 9 is a diagram showing a conventional example of a connection structure between electrode terminal rows. In the figure, 1 is a device terminal portion, 2 is a cable terminal portion, 3 is a conductive film, and 30 is a metal particle.

Claims (1)

(57) [Claims] 1. A device terminal section (1) having an electrode terminal row arranged in parallel, and a cable terminal section having an electrode terminal row arranged in parallel at the same pitch as the electrode terminal row of the terminal section (1). And 2) facing each other so that both electrode terminal rows are overlapped with each other, and pressing and heating and bonding with the conductive film (3) interposed therebetween to connect the electrode terminal rows, wherein the device terminal section (1) and the cable the sum of the electrode width of the respective electrode terminal row of the terminal portions _{(2) (w 1, w} 2) (w 1 + w 2) is,
A connection structure between electrode terminal rows, wherein the margin is larger than the electrode pitch (p), and the short-circuit and open-mode misalignment margins due to misalignment (δ) between the center of both electrode terminals are equal. .