JP2902534B2 - Liquid crystal display - Google Patents

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.
More specifically, the connection between the liquid crystal display panel and the circuit board on which the drive circuit is formed is a connection having a semiconductor chip.
The present invention relates to a liquid crystal display device made by AB (tapeautomated bonding).

[0002] Here, TAB means that a large number of foil-like lead wires are held by a flexible film, connect one circuit terminal portion to the other circuit terminal portion, have flexibility, and This means that a semiconductor chip for signal processing is provided in the middle of a line.

[0003]

2. Description of the Related Art In public facilities such as train stations, a plurality of display modules each having a light emitting element such as an LED as a pixel are conventionally arranged in a vertical and / or horizontal direction for the purpose of displaying a destination or displaying a commercial advertisement. A display board is used. However, liquid crystal display devices have low power consumption,
With the recent increase in performance and cost reduction, display boards employing liquid crystal display devices have attracted attention, and are being developed and put into practical use. When a liquid crystal display device is used, it is necessary to provide a driving circuit board for driving the liquid crystal display panel. In order to display characters or graphics as a large screen by continuously arranging the liquid crystal display devices, it is preferable that the distance between the liquid crystal display devices is small. The circuit board is provided on the side of the liquid crystal display panel via the TAB on the back side of the liquid crystal display panel. Attached so as to extend at right angles. In this case, the number of terminals of the electrode film on the liquid crystal display panel side is very large, and it is difficult to connect to the driving circuit board side via the flexible circuit board with the large number of terminals. Therefore, a semiconductor element is mounted and connected to the circuit board using TAB with a reduced number of wires by signal processing.

[0004]

A liquid crystal display device constituting a large display board has a TAB at a side end of the liquid crystal display panel.
Each lead terminal of the circuit board is connected through the, and is bent in the vertical direction to the liquid crystal display panel using TAB. However, if the end of the TAB lead wire and the terminal of the circuit board are connected at the end of the circuit board, any external force applied to the circuit board or the like is applied to the connection at the end of the lead wire, and the connection is very thin. Since the wires are connected by soldering or the like, there is a problem that the wires are easily damaged by a slight external force.

For this reason, it is conceivable that the TAB is overlapped on the circuit board and held on the circuit board by the cover film portion on the back of the TAB. However, the semiconductor chip provided on the TAB collides with the circuit board, and on the contrary, the lead wire is not provided. There is a problem that a load is imposed on the connection part.

An object of the present invention is to solve such a problem and to provide a liquid crystal display device having a structure capable of reliably and reliably connecting a liquid crystal display panel, a TAB, and a circuit board.

[0007]

According to the liquid crystal display device of the present invention, a terminal portion of a circuit board on which a drive circuit is formed is connected to an electrode terminal of the liquid crystal display panel via a TAB having a semiconductor chip on the back side thereof. A liquid crystal display device to be connected,
The semiconductor chip is exposed through the opening of the TAB.
Electrically connected to the TAB lead wire
The surrounding area is fixed with resin, and
And a notch is provided at an end of the circuit board, and a terminal portion of the circuit board is provided at a center side of the notch, so that the TAB and the circuit board overlap and the notch is provided. The TAB and the circuit board are arranged such that the semiconductor chip fixed by the resin is inserted into the portion, and the lead wire of the TAB is connected to a terminal of the circuit board. The connected TAB and circuit board are respectively connected to two opposite sides of the liquid crystal display panel such that the semiconductor chip is on the back side, and the liquid crystal display panel is mounted on a case having side walls. And the TAB is bent downward along the side wall, and is fixed to the side wall of the case by screws via a support plate applied to the front side of the TAB. There.

[0008]

According to the liquid crystal display device of the present invention, the other end of the TAB having one end connected to the side surface of the liquid crystal display panel is connected to the circuit board so as to overlap the semiconductor chip portion, and Since the notch is provided in a part of the circuit board in the semiconductor chip portion, the circuit board does not hit the semiconductor chip, but is held by the protective resist portion on the back side of the TAB, and is unnecessary for the connection portion of the lead wire. No force is applied. Therefore, protection of the TAB lead wire is achieved, and the reliability is greatly improved.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a liquid crystal display device of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a perspective explanatory view of one embodiment of the liquid crystal display device of the present invention, FIG. 2 is an enlarged plan view of a connection portion between a TAB and a circuit board, and FIG. 3 is a sectional view taken along line III-III of FIG.

As shown in FIG. 1, the liquid crystal display device of the present invention has a liquid crystal display panel 1 and a driving circuit mounted on both side end surfaces of the liquid crystal display panel 1 so as to extend in a direction perpendicular to the liquid crystal display panel. TAB for electrically connecting the substrate 2 to the liquid crystal display panel 1 and the driving circuit substrate 2
3 and a semiconductor chip 4 mounted on the TAB 3.

The liquid crystal display panel 1 has a liquid crystal material sandwiched between two transparent substrates such as glass and plastics. An electrode film is formed so as to face each transparent substrate, and between the electrode films. When a voltage is applied, only the display part is blocked from transmitting light to display images such as characters (positive type), and vice versa. At both ends.

The circuit board 2 for driving the liquid crystal display panel has a drive circuit in which electronic components such as ICs are mounted on a circuit board such as a printed board.
A notch 5 for inserting the semiconductor chip 4 mounted on the TAB 3 is provided at an end of the circuit board 2 on the side connected to the liquid crystal display panel 1. The size of the notch 5 is preferably, for example, about 6 to 7 mm in length and about 6 to 7 mm in width when the semiconductor chip 4 has a side of about 5 mm square. The notch 5 is for inserting the semiconductor chip 4 mounted on the TAB 3 when the TAB 3 and the circuit board 2 are overlapped as described later.
The terminal portion (not shown) of the circuit board 2 connected to the end of the lead wire 3b is provided further on the center side than the cutout portion 5.

Also, as shown in FIGS.
3 is a front side film 3a for protecting the thin lead wire 3b.
And a resist 3c on the back side, for example, about 75 μm made of a polyimide film or a polyester film.
The film 3a having a thickness of about 5 mm is made of tin or gold-plated copper film.
It is provided on the surface of the lead wire 3b having a width of about 100 μm. A lead wire 3b is provided on the back side of the lead wire 3b.
A resist 3c made of epoxy resin or the like and having a thickness of about 20 .mu.m is provided to protect the lead wires 3b from the connection ends of the lead wires 3b and the circuit board for connection to the connection terminals of the drive circuit board 2. Film 3a and resist 3c
Are partially removed to form the terminal portion 6. Also,
The opposite side of the lead wire 3b of the TAB 3 is the liquid crystal display panel 1
Are bonded to the respective electrode terminals by an anisotropic conductive adhesive film or the like.

For example, about 80 lead wires 3b are arranged on the liquid crystal display panel 1 side and about 20 lead wires 3b are arranged on the circuit board 2 side, and one side provided at a position distant from the terminal section 6 by about 5 mm, for example. For example, each end protrudes into a square opening 7 of about 5 mm. The semiconductor chip 4 is disposed in the opening 7 and the liquid crystal display panel 1 is provided.
And the respective lead wires 3 on the drive circuit board 2 side
The semiconductor chip 4 is connected to “b” via the bump 8.

The semiconductor chip 4 is located on the back side of the TAB 3.
In order to mount the lead wire 3b, the lead wire 3b
A bump 8 made of gold, solder, or the like is formed on the back side of the tip of the semiconductor chip 4 and the semiconductor chip 4 is fixed by thermocompression bonding at 400 to 500.degree. After that, a resin such as an epoxy resin is applied to the opening 7 to form a protective film 9 for protecting the thin lead wires and the semiconductor chip portion.

TAB 3 on which this semiconductor chip 4 is mounted
Is aligned with the electrode terminals of the liquid crystal display panel 1 and connected by, for example, an anisotropic conductive adhesive film. Then, the lead terminal 6 at the other end of the TAB 3 matches the terminal of the circuit board 2, In addition, after the semiconductor chip 4 is positioned so as to be inserted into the notch 5 of the circuit board 2, the terminal portion 10 of the circuit board 2 and the end of the lead wire 3b of the TAB 3 are joined by, for example, hand soldering or thermocompression bonding. Connected by soldering according to the law. This connection may be made by a conductive adhesive other than the soldering, such as the anisotropic conductive adhesive film described above.

After that, the circuit board 2 is firmly fixed by bending at the TAB 3 portion and fixing it to the case 13 with the support plate 11 and the screws 12, so that no load is applied to the TAB 3 and cutting of the lead wire 3b is performed. No problem.

According to the present invention, as described above, the TAB 3 and the circuit board 2 are overlapped until the semiconductor chip 4 reaches the circuit board 2, and the notch 5 is formed in the circuit board 2 in the semiconductor chip 4. There is a characteristic in the place where it is provided.

As a result, even when the semiconductor chip must be mounted on the back surface of the TAB 3, the semiconductor chip 4 escapes and the TAB 3 and the circuit board 2 come into planar contact over a wide range, and the lead wire 3b of the TAB 3 Even after the terminals of the circuit board 2 are connected by soldering or the like, a force is not applied only to the soldered portion at the distal end of the weak lead wire 3b, so that a stable distribution of force is achieved. In addition, by using this contact portion and fixing it with, for example, a double-sided tape, a soldering portion at the tip of the lead wire 3b is not further applied, and the reliability of the connection portion with the terminal portion of the circuit board 2 is further improved. Can be done. After the circuit board 2 is bent at the TAB 3 as described above, the case 13 is
In this case, since the TAB 3 and the circuit board 2 can be fixed at the same time, the reliability is further improved.

In the above embodiment, an example was described in which the circuit boards were connected to both sides of the liquid crystal display panel, but they may be connected not only to both sides but also to one side or three or four sides.

[0021]

According to the present invention, the connection between the other end of the TAB having one end connected to the liquid crystal display panel and the circuit board and the semiconductor mounted on the back surface of the TAB in the circuit board are provided. Since the tip has escaped, T
AB and the circuit board are held by planar contact over a wide range, and no force is applied only to the connection portion of the TAB lead wire tip, so that the reliability of the connection portion can be greatly improved.

[Brief description of the drawings]

FIG. 1 is an explanatory perspective view of one embodiment of a liquid crystal display device of the present invention.

FIG. 2 is an enlarged plan view of a connection portion between a TAB and a circuit board.

FIG. 3 is a sectional view taken along line III-III in FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid crystal display panel 2 Circuit board 3 TAB 4 Semiconductor chip 5 Notch part 8 Bump

Claims (1)

(57) [Claims] To 1. A electrode terminals of the liquid crystal display panel, the terminal portion of the circuit substrate over which the driver circuit is formed, a liquid crystal display device which is connected via a TAB having a semiconductor chip on the back surface side, the semiconductor The chip is exposed through the opening of the TAB.
Electrically connected to the TAB lead wire
The surrounding area is fixed with resin, and
And a notch is provided at an end of the circuit board, and a terminal portion of the circuit board is provided at a center side of the notch, so that the TAB and the circuit board overlap and the notch is provided. The TAB and the circuit board are arranged such that the semiconductor chip fixed by the resin is inserted into the portion, and the lead wire of the TAB is connected to a terminal of the circuit board. The connected TAB and circuit board are respectively connected to two opposite sides of the liquid crystal display panel such that the semiconductor chip is on the back side, and the liquid crystal display panel is mounted on a case having side walls. A liquid crystal display device wherein the TAB is bent downward along the side wall, and is fixed to the side wall of the case by screws via a support plate applied to the front side of the TAB.