JPH0533009Y2 - - Google Patents

Description

[Detailed explanation of the invention] <Industrial application field> This invention is generally used to bond a large-scale integrated circuit to a tape-shaped base film.
Concerning improvements to a tape-type integrated circuit board called TABLSI.

<Prior art> Many small portable devices such as word processors and personal computers use liquid crystal display elements in their displays. Demand is also getting stronger. The connection between the liquid crystal display unit and the control circuit is generally made using a rubber connector or a flexible printed circuit board, but these both have limitations in miniaturization because they use a printed circuit board equipped with a package-type LSI. There is.

To solve this problem, TAB (TapeAutomatedBonding) LSI (hereinafter referred to as
Attempts have been made to use tape-type integrated circuit boards (or simply integrated circuit boards), and some are beginning to be put into practical use. In this case, in order to make the display section more compact, the integrated circuit board is bent and the printed circuit board and the integrated circuit board are connected on the back side of the liquid crystal display element.

By the way, as shown in FIG. 3, the terminal portion of the liquid crystal display element 1 is different between the SEG terminal 11 and the COM terminal 12. is attached to the top surface of the glass 14. Therefore, as shown in FIG. 4, when connecting the tape-type integrated circuit board 2 to the liquid crystal display element 1, when connecting it to the SEG terminal 11, it is bent so that the base film 21 is on the inside and the conductor 22 is on the outside. When connecting to the COM terminal 12, the base film 21 is bent on the outside and the conductor 22 is on the inside. 23 indicates an LSI bonded to the base film 21.

Figure 5 shows the state in which the connections are made in this way and the liquid crystal display unit is assembled as a set. 3 is a printed circuit board, 4 is a chassis,
5 is jumper wire for connection between SEG printed boards,
6 indicates jumper wires for connection between the COM printed circuit board and the SEG printed circuit board.
Further, FIG. 6 shows a conventional tape-type integrated circuit board 2a, in which a portion to be bent is punched out to form an elongated slit 24 in advance to make it easier to bend.

<Problem to be solved by the invention> As shown in Figure 4a, when connecting the tape-type integrated circuit board 2 to the SEG terminal 11, the base film 21 is bent inside, which is different from the conventional tape-type integrated circuit board 2. In the case of the circuit board 2a, each slit 24 is bent approximately 90 degrees as shown in FIG. At this time, a tensile stress is applied to the conductor 22, and the base film 21 is bent inward at areas other than both ends of the slit 24 in the longitudinal direction, and the width of the slit is narrowed, so the tensile stress applied to the conductor 22 does not become so large. ,
Since the width of the slit remains wide near the end portion 24a, a large stress is applied to the conductor 22 at that portion. For this reason, the possibility of wire breakage due to environmental stress is extremely high.
When conducting a thermal shock test in which the conductor was left at 70°C for 30 minutes alternately, the conductor, which normally withstands 100 cycles, broke in less than 30 cycles.

Conventionally, in order to solve these problems, the slit 24 was formed long and the conductor 22 was wired inside the slit 24 as far away from both ends as possible, or a dummy conductor that was wider and stronger than a normal conductor was used. Measures have been taken, such as providing the slits 24 near both ends 24a. However, if you try to make the slit longer, the stress applied to the slit during the manufacture of tape-type integrated circuit boards will cause the conductor to wrinkle or warp when pasted onto the film, making it difficult to produce a uniform conductor-attached film. Further, when a dummy conductor is provided, the actual wiring space for the conductor becomes narrower, and the wiring pitch of the conductor becomes smaller, resulting in problems such as a decrease in yield during manufacturing.

This invention was developed in view of these problems, with the purpose of providing a tape-type integrated circuit board that does not break due to bending.

<Means for solving the problem> In order to achieve the above-mentioned object, this invention provides a tape-type integrated circuit board in which an integrated circuit is bonded to a flexible tape-shaped base film, with two elongated slits arranged parallel to each other in the portion of the base film that will become the bent portion.

<Function> The amount of bending per slit at both ends of the slit is half that of the conventional method with one slit, so the tensile stress applied to the conductor is significantly reduced, and the conductor can be placed near both ends of the slit. The possibility of wire breakage decreases even if the wire is disconnected.

<Example> Next, an example shown in the drawings will be described. FIG. 1 is a diagram showing a tape-type integrated circuit board 2 of the embodiment, and FIG.
The figure is a perspective view of the integrated circuit board 2 folded and wired, and the same parts as in the above description are denoted by the same reference numerals, and redundant explanation is omitted.

In the figure, 25 is a slit provided in the bent portion of the base film 21;
Two slits 24 which are thinner than the conventional slits 24 are arranged in parallel. The base film 21 may have a thickness of, for example, an aromatic polymide film.
The size of each slit 25 is 0.4 mm, the length is 22 mm, and the distance between two adjacent slits 25 is 0.4 mm. The conductor 22 is a copper wiring plated with tin of 1 μm or less, and the thickness of the copper is 1 oz (approximately 35 μm).
It is. Although a large number of conductors 22 are provided,
Intermediate parts are omitted and only a part is shown. Furthermore, similar effects can be expected even if Upilex film is used as the base film 21.

When the tape-type integrated circuit board 2 having such a structure is bent and connected to the liquid crystal display element 1, as shown in FIG. As a result, each slit 25 is bent at an angle of 45 degrees at the end 25a of each slit 25, resulting in a smooth bend as a whole. When we conducted a thermal shock test on the integrated circuit board 2 bent in this way by leaving it at -25°C and 70°C for 30 minutes alternately as described above, no disconnection occurred even after 100 cycles or more. Even in the bending test, the conductor 22 did not break, confirming that its durability against wire breakage was greatly improved.

<Effects of the Invention> As is clear from the above-described embodiments, the tape-type integrated circuit board of this invention has two elongated slits arranged in parallel in the bent portion of the base film.

Therefore, when connected to a liquid crystal display element in a bent state, the stress applied to the conductor is reduced, making it less likely that wires will break when incorporated into a liquid crystal display unit, making it ideal for display parts of devices such as word processors and personal computers. This makes it possible to improve the reliability of liquid crystal display units used in

[Brief explanation of the drawing]

1a and 1b are a front view and a side view, respectively, of an embodiment of the invention, FIG. 2 is a perspective view of the device bent and wired to a liquid crystal display element,
Figures a, 3b and 3c are respectively a front view, a top view and a side view of a liquid crystal display element, and Figures 4a and 4b are respectively a tape-type integrated circuit board attached to a liquid crystal display element. Figure 5 is a side view of the connected state, and Figure 6a is a perspective view of a liquid crystal display unit assembled by connecting the tape-type integrated circuit board to the liquid crystal display element.
6b are a front view and a side view of the conventional example, respectively, and FIG. 7 is a perspective view of the conventional example in a bent and wired state. DESCRIPTION OF SYMBOLS 1...Liquid crystal display element, 2...Tape type integrated circuit board, 21...Base film, 22...Conductor, 2
3...LSI, 25...slit, 25a...end of slit.

Claims (1)

[Scope of utility model registration request] A tape-type integrated circuit board formed by bonding an integrated circuit to a flexible tape-like base film, characterized in that two elongated slits are provided in parallel in a bent part.