JP2894728B2 - Liquid crystal display device and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a liquid crystal display device with a reduced thickness and a method for manufacturing the same.

(Prior Art) In various liquid crystal display devices such as a liquid crystal television, a display portion is formed large, but an electronic circuit other than the display portion is desired to be as small and compact as possible.

Conventionally, wire bonding (WB), tape automatic bonding (TAB), flip chip bonding (FCB), and the like have been used for assembling this type of electronic circuit. All of these use bare ICs as driving ICs, and can be said to be IC high-density mounting technologies aimed at miniaturization rather than those in a flat package.

Of these, tape automatic bonding is
It is superior in mass productivity compared to wire bonding, and has better stress reliability than flip-chip bonding, and can easily mount resistors, capacitors, and inductor passive component chips for spurious noise reduction filters. For this reason, it is widely adopted as an IC mounting technology for various liquid crystal display devices such as liquid crystal televisions.

For example, in a high-definition, high-definition image quality LCD, the display area of the glass substrate of the liquid crystal panel is 4 inches, and about 100,000 thin film transistors (TFTs) are arranged in the display area in a row and column direction. It is arranged to have the nature. Each of these thin film transistors constitutes a unit pixel, is connected to an independent transparent electrode for each unit pixel region, and applies a specific potential to a counter electrode provided through a liquid crystal, thereby obtaining a liquid crystal. Open the shutter.

Conventionally, as this type of liquid crystal display device, for example, a configuration described in Japanese Utility Model Laid-Open Publication No. Sho 60-82684 is known.

The liquid crystal display device described in Japanese Utility Model Application Publication No. 60-82684 is
Arrange a printed wiring board on the back side of the liquid crystal panel, connect the liquid crystal panel and the printed wiring board with a flexible board,
The printed wiring board is fixed by a support.

(Problems to be Solved by the Invention) Further, when the liquid crystal panel is of a transmission type, it is generally necessary to arrange a light source on the back side of the liquid crystal panel.

However, in the case of the liquid crystal display device described in Japanese Utility Model Application Laid-Open No. 60-82694, the thickness of the liquid crystal display device is the sum of the thicknesses of the liquid crystal panel, the printed wiring board, and the support, and the thickness can be reduced. Has problems that are difficult.

The present invention has been made in view of the above problems, and has as its object to provide a liquid crystal display device having a reduced thickness and a method of manufacturing the same.

[Configuration of the invention]

(Means for Solving the Problems) The present invention provides a transmissive liquid crystal panel having a predetermined display portion and a terminal at a peripheral portion, and a drive connected to one end of the liquid crystal panel for driving the liquid crystal panel. A plurality of tape carriers mounted with an IC for the outside and bent outside the connection portion with the liquid crystal panel, and circuit wiring connected to the other end side of each of the tape carriers and input to each tape carrier,
A printed wiring board disposed on the back side of the liquid crystal panel, and an opening disposed on the back side of the liquid crystal panel and corresponding to the display unit, wherein the printed wiring board is fixed around the opening. 1 support.

The first support has a recess corresponding to the printed wiring board.

Further, a second support is provided which has an opening facing the first support and corresponding to the opening of the first support, and which holds the printed wiring board together with the first support. Things.

(Operation) According to the present invention, a first support is disposed on the back side of a liquid crystal panel having an opening corresponding to a display unit, and a printed wiring board is fixed around the opening to form a transmission type liquid crystal panel. In such a case, a light source is often arranged on the back surface of the liquid crystal panel. Therefore, if the light source is made to correspond to the opening of the first support, the thickness can be reduced.

Further, since the first support has a concave portion corresponding to the printed wiring board, the thickness can be further reduced.

Furthermore, by sandwiching the printed wiring board between the first support and the second support, the printed wiring board can be easily and reliably arranged at a predetermined position, and assemblability is improved.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

1 to 4, a liquid crystal panel 11 has a large number of thin film transistors, transparent electrodes, and the like constituting a unit pixel on two glass substrates 11A and 11B.
Liquid crystal is sealed between the glass substrates 11A and 11B. The glass substrate 11A on the back side is larger than the glass substrate 11B on the front side, and the edge protrudes outward.
The liquid crystal panel 11 need not be a so-called FTF-LCD using thin film transistors, but may be another active matrix display device or a dot matrix display device. In any case, the liquid crystal panel 11 has glass substrates 11A and 11B, and a large number of lead terminals for driving pixels are arranged on the peripheral portion of the glass substrate 11A on the back side, for example, on three sides. With respect to the number of terminals, that is, the number of terminals in the vertical direction and the number of terminals in the horizontal direction, for example, a liquid crystal panel having a diagonal of 4 inches requires 220 terminals in the vertical direction and 480 terminals in the horizontal direction. And, as a driving IC for driving each pixel via each of these terminals, for example, 11
The one having 0 elements built in one chip is used, and the one having 120 elements built in one chip in the horizontal direction is used. In other words, driving is performed using two 110-element ICs in the vertical direction, and driving using four 120-element ICs in the horizontal direction.

Here, the vertical and horizontal sides of the display unit with a diagonal of 4 inches are 60 mm x
80mm. If the pitch of the terminals arranged on the periphery of the liquid crystal panel 11 is smaller than 200 μm, the connection technology becomes sophisticated and connection becomes difficult, so the horizontal side is divided into an upper side and a lower side, and
The terminal pitch is set to 333 μm by arranging the terminals one by one. The terminal pitch is 272 even if the vertical side is only one side.
μm, and two ICs are arranged on one side of one side.

The vertical driving IC 12Y and the horizontal driving IC 12X are mounted on and electrically connected to the corresponding plurality of tape carriers 13Y and 13X, respectively. This connection is made by the drive IC12X and 12Y terminals with gold (Au) bumps formed and the copper (Cu) lead to tin (Su)
After aligning the terminals of the plated polyimide film-based tape carriers 13X and 13Y with the terminals, Au / Sn eutectic is performed by heating and pressing, and then joined, so-called ILB (Inner Lead B
onding).

Next, what is called OLB (Outer Lead Bonding), in which the tape carriers 13X and 13Y on which the driving ICs 12X and 12Y are mounted as described above, are connected to the terminals at the peripheral portion of the liquid crystal panel 11, is called an OLB (Outer Lead Bonding). A conductive film is used. That is, the terminals of the liquid crystal panel 11 and the output terminals on one end side of the tape carriers 13X and 13Y are formed at the same pitch, and after the terminals of the liquid crystal panel 11 and the tape carriers 13X and 13Y are aligned, the anisotropic The terminal of the liquid crystal panel 11 and the tape carriers 13X and 13Y are connected by heating and pressing with the conductive film interposed therebetween.

Further, the printed wiring board 14 includes four elongated printed wiring boards 14 a, which are divided and formed corresponding to each side of the liquid crystal panel 11.
14b, 14c and 14d, of which three printed wiring boards 14
In a, 14b, and 14c, the circuit groups that individually connect the terminal groups of the driving ICs 12X and 12Y and that apply specific voltages and signals to the input terminals of the driving ICs 12X and 12Y are formed. .
Further, another printed wiring board 14d is provided with a control IC 16 and a signal input / output unit 17 such as a signal input / output cable or FPC is connected to the printed wiring boards 14a, 14b, 14c. Circuit wiring for supplying a control signal from a control IC 16 for controlling the drive to the drive ICs 12X and 12Y is formed. Then, divided printed wiring boards 14a, 14b, and 14c are provided for each side of the liquid crystal panel 11 having the tape carriers 13X and 13Y, and the input terminals on the other ends of the tape carriers 13X and 13Y are printed. Solder connections are made to the terminals of the boards 14a, 14b, 14c, respectively.

Reference numerals 21 and 22 denote a pair of plate-like first and second supports formed of a synthetic resin such as an ABS resin, respectively. An opening 23 corresponding to the display section of the liquid crystal panel 11 is provided in the upper first support body 21, and a concave step 24 corresponding to the outer shape of the liquid crystal panel 11 is formed around the opening 23 on the upper surface side. In addition, a concave portion 25 corresponding to each of the printed wiring boards 14a, 14b, 14c, and 14d is formed on the four sides on the lower surface side, and a control portion is provided above the concave portion 25 corresponding to one printed wiring board 14d. The storage recess 26 of the IC 16 is formed. The lower second support 22 has an opening 27 corresponding to the opening 23 of the first support 21. The printed wiring boards 14a and 14b are provided on three sides around the opening 27 on the upper surface side. , 14c corresponding to the driving ICs 12X,
12Y storage recesses 29 are formed, and wiring recesses 30 are formed at both ends of each recess 28.

Then, the liquid crystal panel 11 has the tape carriers 13X, 13Y
After connecting the printed wiring boards 14a, 14b, and 14c to the tape carriers 13X and 13Y,
The first support 21 is disposed on the back of
3X, 13Y LCD panel from outside of the connection with LCD panel 11
Fold it almost in a U-shape to the back side of 11. In this case, if the polyimide base film corresponding to the bent portion is partially removed, no stress is generated in the OLB portion even when bent.

Then, the three printed wiring boards 14a, 14b, 14c arranged on the back side of the liquid crystal panel 11 by bending each of the tape carriers 13X, 13Y fit into the recess 25 of the first support 21,
Further, the other printed wiring board 14d is fitted in the recess 25 with the control IC 16 positioned in the storage recess 26. Then, the printed wiring boards 14a, 14b, 14c, 14d are connected by soldering using a predetermined cable or the like.

Next, the second support 22 is brought into contact with the lower surface of the first support 21, and the printed wiring boards 14a, 14b, 14c are positioned in the recesses 28, and the driving ICs 12X, 12Y are stored in the recesses. Located within 29,
Furthermore, the printed wiring board 14d is supported on a plane, and
The connection cables and the like between the printed wiring boards 14a, 14b, 14c, 14d are housed in the recesses 30, and the printed wiring boards 14a, 14b, 14c, 14d
Is sandwiched between the first support 21 and the second support 22.

The printed wiring boards 14a, 14b, 14c, 14d and a pair of first
In the step of assembling with the first and second support members 21 and 22, the positioning pins provided in advance on the first and second and support members 21 and 22 and the positioning holes to be fitted to the positioning pins are used.

As described above, the printed wiring board 14 having the circuit wiring to be input to each of the tape carriers 12X and 12Y is divided into small printed wiring boards 14a, 14b, 14c and 14d, thereby forming a single large board. The cost of the printed wiring board 14 can be reduced as compared with that of the liquid crystal panel. Therefore, the cost of the liquid crystal display device can be reduced, and the larger the area of the display unit of the liquid crystal panel 11, the greater the effect.

The printed wiring board 14 is a small printed wiring board 14a,
Before being divided into 14b, 14c, 14d and assembled on the back side of the liquid crystal panel 11, the input terminals of the tape carriers 13X, 13Y and the terminals of the printed wiring boards 14a, 14b, 14c can be connected by soldering,
In addition, since this soldering connection can be made at a position away from the polarizing plate 18 of the liquid crystal panel 11, the yield can be improved without contaminating the polarizing plate 18 with flux, solder, or the like. The plates 14a, 14b, 14c, 14d can be easily and reliably arranged at predetermined positions by being sandwiched between the pair of first and second supports 21, 22,
Good assemblability. In this case, each printed wiring board 14a, 14b, 14
If c and 14d and the pair of first and second supports 21 and 22 are connected and fixed by a positioning pin, a positioning hole, or the like, assembly can be performed without a special jig or tool.

Incidentally, as in the above embodiment, each of the tape carriers 13X, 13X
The printed wiring boards 14a, 14 connected to this by bending Y
By arranging b and 14c on the back side of the liquid crystal panel 11,
The width of the frame around the liquid crystal panel 11 can be reduced, but in some cases, the printed wiring boards 14a, 14b, 14c
Some of them, for example, only the tape carrier 13Y of the printed wiring board 14b is bent, and the other printed wiring boards are arranged outside similarly to the printed wiring board 14d, and a pair of first
Alternatively, it may be held between the first supports 21 and 22.

〔The invention's effect〕

According to the present invention, in the case of a transmissive liquid crystal panel, a first support is arranged on the back side of a liquid crystal panel having an opening corresponding to a display unit, and a printed wiring board is fixed around the opening. In many cases, a light source is arranged on the back of the liquid crystal panel. Therefore, if the light source is made to correspond to the opening of the first support, the thickness can be reduced.

[Brief description of the drawings]

1 is an exploded perspective view showing an embodiment of the liquid crystal display device according to the present invention, FIG. 2 is a plan view showing an assembled state of FIG. 1, FIG. 3 is a cross-sectional view taken along the line III-III of FIG. Fig. 4 is Fig. 2 IV-
FIG. 4 is a sectional view of an IV part. 11… LCD panel, 12X, 12Y… Drive IC, 13X, 13Y…
... tape carrier, 14, 14a, 14b, 14c, 14d ... printed wiring board, 21 ... first support, 22 ... second support, 23, 2
7 ... opening, 25, 28, 30 ... recess.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G09F 9/00

Claims (4)

(57) [Claims] 1. A liquid crystal display device comprising: a transmissive liquid crystal panel having terminals on a predetermined display portion and a peripheral portion; and a driving IC connected to one end of the liquid crystal panel and driving the liquid crystal panel. A plurality of tape carriers bent outside the connection portion with the panel, and a circuit wiring connected to the other end of each of the tape carriers and input to each of the tape carriers, are arranged on the back side of the liquid crystal panel. A printed wiring board, and a first support that has an opening disposed on the back side of the liquid crystal panel and corresponds to the display unit, and that fixes the printed wiring board around the opening. Characteristic liquid crystal display device. 2. The liquid crystal display device according to claim 1, wherein the first support has a recess corresponding to the printed wiring board. 3. A second support which has an opening facing the first support and corresponding to the opening of the first support, and which holds the printed wiring board together with the first support. 3. The liquid crystal display device according to claim 2, comprising: 4. A liquid crystal display, comprising: a transmissive liquid crystal panel having terminals on a predetermined display portion and a peripheral portion; and a driving IC connected to one end of the liquid crystal panel and driving the liquid crystal panel. A plurality of tape carriers bent outside the connection portion with the panel, and circuit wiring connected to the other end side of each of these tape carriers and input to each tape carrier,
A printed wiring board disposed on the back side of the liquid crystal panel, and an opening disposed on the back side of the liquid crystal panel and corresponding to the display unit, wherein the printed wiring board is fixed around the opening. 1. A method of manufacturing a liquid crystal display device comprising: the support of (1), wherein the liquid crystal panel and the printed wiring board are connected, the tape carrier and the printed wiring board are connected, and the tape carrier is bent. A method for manufacturing a liquid crystal display device, comprising: positioning the printed wiring board on the back side of the liquid crystal panel; and fixing the printed wiring board with the support.