JPH08139132A - Carrier tape - Google Patents

Abstract

PURPOSE: To provide a carrier tape which is used for a flexible printed wiring board implemented to apparatus by bending, wherein a lead wire does not snap at the bend, even if a lead wire width of TAB becomes fine. CONSTITUTION: A carrier tape is constituted so that subslits 16 to 22 are formed at a position with a TAB external form line 10 to be blanked out, which are spaced a predetermined distance from both ends of slits 6 and 7 on a lead wire bend.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carrier tape, and more particularly to a carrier tape for a flexible printed circuit board which is folded and mounted on an apparatus.

[0002]

2. Description of the Related Art As a flexible printed circuit board to be bent and mounted, for example, TAB (Tape Automated) is used.
attached Bonding). TAB is obtained by bonding a large-scale integrated circuit to a flexible base film such as a polyimide film. For example, a TAB used for a liquid crystal display device has a driver IC for driving a liquid crystal as a large-scale integrated circuit, and is connected between a liquid crystal display panel and a printed circuit board for a liquid crystal display.

As an example, referring to FIG. 4, a conventional TA used in an active matrix type liquid crystal display panel using a TFT (thin film transistor) as a switching element.
B will be described. X driver board 32 for driving data lines
Are attached to the upper side of the liquid crystal display panel 30 via eight TABs 34. TAB34 has a liquid crystal drive IC
42, and slits 46 and 48 for bending the TAB 34 are formed. Liquid crystal display panel 3
A Y driver substrate 40 for driving a scanning line is attached to the 0 side surface via a TAB 38. In order to make the display peripheral portion of the panel 30 compact, as shown in FIG. 5 from the state of FIG. 4, the TAB 34 in which the lead wire 50 is adhered to the liquid crystal display panel 30 by, for example, ACF is 90 degrees at the slit 46, and Bend 90 degrees at the slit 48,
Bend 180 degrees as a whole and press X on the back of the liquid crystal display panel 30.
The connection with the driver board 32 is made. The slits 46 and 48 facilitate this bending and make TAB3
4 is formed along the bending line of the TAB 30 in order to reduce cracks and breaks in the bending portion of the lead wire 50.

The TAB 34 is a TAB as shown in FIG.
Formed from a carrier tape. A conventional TAB carrier tape will be described with reference to FIG. A sprocket hole 2 and a device hole 4 for mounting a large-scale integrated circuit are formed by punching in a longitudinal direction of a resin tape 1 serving as a base film of TAB. At the same time, slits 6 and 7 are formed in the TAB bent portion by punching. The slit 8 is also formed by punching at the same time, but this is not used for bending, but used for soldering the printed circuit board and the lead wire of the TAB in the area of the slit 8.

After a lead pattern is formed on the carrier tape, a predetermined driver IC is mounted in the device hole 4, and punched along the TAB outline 10, a TAB 34 is formed from the carrier tape.

The dimensions of the TAB 34 to be formed are shown in FIG.
As shown in the figure, the width C of the TAB 34 is 26 mm,
4, the length B of the slits 46 and 48 (slits 6 and 7) is 24 mm, and the widths A and A ′ of the suspenders 12 and 14 are 1 each.
mm. These suspenders 12 and 14 are TAB
It is a base film region (a region surrounded by a broken line in the figure) sandwiched between the outline 10 and both ends of the slits 6 and 7. When mounting the TAB 34, the suspenders 12 and 14 may be provided with the slit 46 or the slit 48 of the TAB 34.
(Corresponding to the slits 6 and 7 of the carrier tape) does not generate excessive tensile stress on the lead wire, and also functions as an elastic member when the TAB is bent to function as the suspenders 12 and 1.
It has an important function of making the curvature of the lead follow the curvature of 4. The suspenders 12 and 14 have these functions
In order to exhibit the effect, both must have the same material mechanical properties, so that the widths of the suspenders 12, 14 are desirably the same as possible.

If the widths of the suspenders 12 and 14 are different from each other, the functions of elasticity at the time of tensile stress and bending are different from each other. However, the problem with TAB using a conventional lead wire having a relatively large lead wire width is as follows. Did not occur. However, with the recent increase in the size and definition of the liquid crystal display panel, the demand for a reduction in the width of the TAB leads has been increasing.
In recent years, it has become necessary to reduce the width of the lead wire of about 80 μm to about half of the width, and the tensile and bending stress of the lead wire itself must be reduced. In such a situation, the mismatch between the material mechanical properties of the suspenders 12 and 14 is a factor that promotes lead disconnection and the like.

[0008]

However, for example, in a module process of a liquid crystal display device or the like, a TA is removed from a carrier tape.
When punching B, it is difficult to punch along the TAB outline 10, and in reality, the suspenders 12, 1
In the vicinity of No. 4, the die is misaligned by about ± 0.5 mm at the maximum from the TAB outline 10 which is the line to be punched, and is punched. Therefore, for example, the width A of the suspenders 12 is 0.5 mm, and the width A ′ of the suspenders 14 is 1.5 mm.
mm, suspenders 1 at both ends of slit 6
In many cases, the widths of 2 and 14 are formed differently. As a result, the mechanical properties of the suspenders with a relatively short width are inferior, and the stress applied to the lead wire that crosses the slit is concentrated on the side with a relatively short width. There is a problem that the possibility of disconnection of the lead wire is increased.

An object of the present invention is to provide a carrier tape in which a lead wire is not broken at a bent portion of the TAB even if the lead wire width of the TAB is reduced. It is a further object of the present invention to provide a carrier tape capable of equalizing the width of the suspenders. It is another object of the present invention to provide a carrier tape that facilitates a punching step for a TAB outline.

[0010]

An object of the present invention is to provide a carrier tape having a slit formed in a bent portion of a lead, having a sub-slit formed at a predetermined distance from both ends of the slit. Achieved by carrier tape. Further, the above object is achieved by a carrier tape, wherein the sub-slit is formed at a position including an outline of a flexible printed board formed by punching. Still further, the above object is achieved by a carrier tape, wherein the slit-side end of the sub-slit has a distance from the outer shape line that is equal to or greater than the amount of punching displacement.

[0011]

According to the present invention, the sub-slit is formed at a position including the outline of the flexible printed circuit board (for example, TAB) to be stamped at a predetermined distance from both ends of the slit of the lead bent portion. A TAB having a suspender formed in the same width, which is not affected by the positioning error of the punching in the punching step, can be formed by punching.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A carrier tape according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a plan view of the carrier tape according to the present embodiment. A sprocket hole 2 and a device hole 4 for mounting a large-scale integrated circuit are formed by punching in a longitudinal direction of a resin tape 1 serving as a base film of TAB. At the same time, slits 6 and 7 are formed in the TAB bent portion by punching. The slit 8 is also formed by punching at the same time, but this is not used for bending, but used for soldering the printed circuit board and the lead wire of the TAB in the area of the slit 8. The above is no different from the conventional carrier tape. The dimensions of the TAB 34 to be formed are, for example, the width C of the TAB 34 is 26 mm, and the length B of the slits 46 and 48 (slits 6 and 7) of the TAB 34 is 24.
The point of being mm is exactly the same as the conventional carrier tape of FIG.

In the carrier tape according to the present embodiment, sub-slits 16 and 18 are formed at distances A and A ′ from both ends of the slit 6. Similarly, the sub-slit 2 is separated from the opposite ends of the slit 7 by a predetermined distance A, A '.
0 and 22 are formed. Sub slits 16-22
Can be formed at the same time when the slits 6 and 7 are punched out. The regions sandwiched between the slit and the sub-slit are the suspenders 12, 14, and their widths A, A 'are each 0.5 mm.

The sub-slit will be described in more detail with reference to FIG. FIG. 2 is an enlarged view of the suspender 12 of FIG. The sub-slit 16 is formed by a stamped TA
It is formed so as to include the B outline 10. The end of the sub-slit 16 on the side of the slit 6 has a distance D from the TAB outline 10 that is equal to or more than the positional deviation of the die punched. In this embodiment, it is usually plus or minus 0.3 m
Although a mold having an accuracy of m or less was used, D was set to 0.5 mm in consideration of an error due to a problem of suddenness during mass production. Although not described, the other sub-slits 18 to 22 have the same configuration.

For example, copper is deposited on the carrier tape on which the slits 6 and 7 having the sub-slits 16 to 22 at the ends are formed and then patterned to form lead wires. In this embodiment, the width of the lead wire is about 40
Microns, the number of leads is about 240, and the lead pitch is about 90 microns. Thereafter, after a tin plating process and a solder resist process, the driver IC is mounted in the device hole 4 and subjected to a wiring process, and the IC is formed with a sealing resin.
To complete the tape carrier.

A TAB 34 is formed from the carrier tape by punching this tape carrier along the TAB outline 10 in the module process of the liquid crystal display device. At this time, even if the positioning error in die punching is within a range of ± 0.5 mm, the sub slit 1
Since the widths of the suspenders 12, 14 determined by 6 to 22 and the slits 6, 7 do not depend on the die punching error and do not change, the suspenders 12, 14 can ensure the same suspender width. .

When suspenders 12 and 14 having the same suspender width are mounted on the TAB 34,
The slits 46 and 48 of the TAB 34 (corresponding to the slits 6 and 7 of the carrier tape) do not generate unreasonable tensile stress on the lead wire, and also function as an elastic member when the TAB is bent, and the curvatures of the suspenders 12 and 14 and the curvature of the lead It is guaranteed that the important effect of obeying the above is achieved.

As described above, according to the carrier tape of this embodiment, even if a die having a positioning error at the time of punching is used, a TAB having the same suspender width can be formed, and the lead wire width can be reduced. However, it is possible to prevent the lead wire from being broken at the bent portion of the TAB.

Further, according to the carrier tape of the present embodiment, the dummy lead for reinforcement which is conventionally provided at the end of the bending slit is not required, and the lead wiring can be easily routed.

Next, a carrier tape according to a second embodiment of the present invention will be described with reference to FIG. This embodiment is based on the premise that a carrier tape is provided with two parallel elongated slits 24 and 26 at a bent portion in order to reduce the amount of bending per lead slit. Slit 2
Sub-slits 16 and 18 are formed at both ends of the suspenders 12 and 14 from both ends of the suspenders 4 and 26. The sub-slits 16, 18 are formed in a rounded trapezoidal shape, with the upper bottom portion facing both ends of the slits 24, 26.

As described above, when there are a plurality of adjacent slits, one sub-channel is provided for the plurality of slits.
A slit may be formed and each suspender may be provided.

The present invention is not limited to the above embodiment, and various modifications are possible. In the above embodiment, the carrier tape in which the slits 6, 7 and 8 are formed at right angles to the direction in which the sprocket holes 2 are arranged has been described. However, for example, even if the slits are formed in parallel to the direction in which the sprocket holes 2 are arranged. The present invention can be similarly applied.

Although the above embodiment has been described with respect to a TAB carrier tape which is bent at 180 degrees, the present invention is not limited to this. The TAB carrier tape may be bent at 90 degrees, that is, a TAB having one bent portion where a slit is formed. It is naturally adaptable.

[0024]

As described above, according to the present invention, the widths of the suspenders are made equal to each other, and even if the lead wire width is miniaturized, the lead wire is not broken at the bent portion and the reliability is improved.
Can be realized, the cost of the mold can be reduced by using the mold with the conventional accuracy, and the punching process with the TAB outline can be facilitated.

[Brief description of drawings]

FIG. 1 is a view showing a carrier tape according to a first embodiment of the present invention.

FIG. 2 is a partially enlarged view of the carrier tape according to the first embodiment of the present invention.

FIG. 3 is a view showing a carrier tape according to a second embodiment of the present invention.

FIG. 4 is a diagram showing a TAB mounting state.

FIG. 5 is a TAB sectional view showing a state in which an X driver substrate is arranged on the back surface of the liquid crystal display panel.

FIG. 6 is a view showing a conventional carrier tape.

[Explanation of symbols]

 Reference Signs List 1 resin tape 2 sprocket hole 4 device hole 6, 7 slit 8 slit 10 TAB outline 12, 14 suspender 16, 18, 20, 22 sub-slit 24, 26 slit 30 liquid crystal display panel 32 X driver board 34, 38 TAB 40 Y driver board 42 Liquid crystal drive IC 46, 48 Slit 50 Lead wire

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masayuki Morimoto 1623 Shimotsuruma, Yamato-shi, Kanagawa 14 Yamabe Works, Japan BM Co., Ltd. (72) Yoshifumi Natsuyama 1623 Shimotsuruma, Yamato-shi, Kanagawa 14 Inside Japan BM Co., Ltd. Yamato Office

Claims (3)

[Claims] 1. A carrier tape having a slit formed in a bent portion of a lead, wherein the carrier tape has sub-slits formed at a predetermined distance from both ends of the slit. 2. The carrier tape according to claim 1, wherein the sub-slit is formed at a position including an outline of a flexible printed circuit board formed by punching. 3. The carrier tape according to claim 2, wherein the slit-side end portion of the sub-slit has a distance equal to or greater than a positional deviation amount of punching from the outer shape line. .