JP3228619B2 - Display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a display device in which a display section of liquid crystal, plasma, EL, or the like is integrated with an IC for driving the display section.

[0002]

2. Description of the Related Art Various methods have been proposed as a means for providing a driving IC in a display device. One example of such a method is a bare chip mounting of an IC. And the IC are connected by wire bonding.

For example, in the field of liquid crystal display devices,
A COG type liquid crystal display device has been proposed. According to this liquid crystal display device, two glass substrates having electrodes on the inner surface are bonded together via a liquid crystal layer, and the periphery of the liquid crystal layer is sealed with a sealing material. The liquid crystal display cell configuration is stopped, and a driving IC is provided on one of the glass substrates,
The wiring terminals extending from the liquid crystal display cell and the driving IC are connected by wire bonding, and the driving IC is also connected to a flexible wiring board for an external connection terminal portion.

In addition, in the liquid crystal display device having this configuration, the connection wiring on the glass substrate is formed of a metal such as aluminum by a thin film process.
It was practically difficult to make the film thickness several μm or more. In particular, when connecting two glass substrates having electrodes on the inner surface thereof through a liquid crystal layer, the thickness of the connection wiring is set to 1 μm in order to make the distance between the substrates strict.
m had to be set around.

However, in the actual COG type liquid crystal display device, when the thickness of the connection wiring is set to about 1 μm, there is a problem that the resistance value of the wiring becomes large and the input signal between the electrodes is deteriorated. In order to solve the problem, the width of the connection wiring has been increased.

However, the occupied area increases due to the width of the connection wiring and the area required for the wiring, and the size of the device itself increases accordingly. In recent years, there has been a tendency to reduce the size of the device. Among them, there was a problem that the requirements were not met.

Further, this connection wiring is formed of a metal material such as aluminum. However, it is practically difficult to mount an electronic component chip on the aluminum connection wiring via solder. , A capacitor, a resistor, and the like cannot be directly mounted on the connection wiring.

On the other hand, in such a COG type liquid crystal display device, it has been proposed to attach a flexible circuit board (FPC) on which a bus line as a connection wiring is formed to a glass substrate (Japanese Patent Laid-Open No. 64-37533). No.).

FIG. 10 is a plan view of a main part of the liquid crystal display device 1 according to the present invention. According to FIG. 10, the upper glass substrate 2 and the lower glass substrate 3 having transparent electrodes (not shown) formed on their opposing surfaces. Liquid crystal is sealed between the two via a sealing material, and a connection pattern 4 connected to the transparent electrodes of the upper glass substrate 2 and the lower glass substrate 3 is formed on the overhang 3a of the lower glass substrate 3. ing. Reference numeral 5 denotes a flip-chip type driver (drive) IC with solder bumps, and reference numeral 6 denotes an FPC on which a bus line 7 is formed. A relay connection pattern 8 to the bus line 7 is formed on the overhang portion 3a by a metal that can be soldered. The FPC 6 is provided with a plurality of terminals 6a corresponding to a group of driver ICs 5 formed with a relay connection pattern 10 connected to the through-hole 9, and the relay connection pattern 10 of the terminal 6a and the relay connection pattern. 8 are electrically connected to each other through soldering or through an anisotropic conductive film. The FPC 6 is bent at a position A indicated by a two-dot chain line in the figure and is positioned on the back surface side of the lower glass substrate 3 so as to save space.

However, the liquid crystal display device 1 having this configuration
Since the solder bumps are used for fixing and electrically conducting the driver IC 5, the relay connection pattern 8 must be further formed, and this leads to an increase in the size of the liquid crystal display device 1 due to extra wiring. There was a problem.

In addition, the line width of each of the relay connection patterns 8, 10 for electrically conducting via soldering or anisotropic conductive film needs to be at least about 3 mm, which also makes the wiring pattern large. Therefore, there is a problem that the size of the liquid crystal display device 1 is increased.

The long FPC 6 is connected to the lower glass substrate 3.
When the FPC 6 is disposed along the overhang portion 3a, it is practically difficult to electrically conduct with high precision due to the flexibility of the FPC 6 itself, and there is a problem that mass productivity is difficult.

Further, the bending position of the FPC 6 is near the end of the lower glass substrate 3, and the bending is forcibly performed in the vicinity of the bending position. As a result, stress is generated in the FPC 6, and the reliability of the FPC 6 itself is significantly reduced. There is also the problem of doing.

Furthermore, in this FPC 6, a bus line 7 is actually provided on one surface, and a relay connection pattern 10 is formed on the other surface via a through hole 9. 2 bus lines
It is practically difficult to form a multilayer structure having more than one layer due to its own bent structure.

Further, instead of the liquid crystal display device 1 provided with the FPC, a configuration in which a so-called TAB in which a driving IC is mounted on a tape carrier, that is, a so-called TAB is provided on a glass substrate has been proposed. FIG. 11 is a cross-sectional view of a main part of the TAB-type liquid crystal display device 11, in which a transparent electrode (not shown) is formed on the opposing surfaces of the upper glass substrate 12 and the lower glass substrate 13 with a sealing material interposed therebetween. (Not shown) is enclosed, and the upper glass substrate 12 is placed on the overhang 13a of the lower glass substrate 13.
And a connection pattern (not shown) connected to each transparent electrode of the lower glass substrate 13. 14 is a driving IC
Reference numeral 15 denotes a TAB mounted on a film carrier 16, and the driving IC 15 is fixed via solder bumps 17 and electrically connected, and the IC 15 is covered with a protective resin 18. Further, a circuit board (PCB) 19 provided with a bus line is connected to the overhanging portion 1 of the lower glass substrate 13.
3a, the circuit board 19 and the overhang 13a
The TAB 14 is fixed on the first and second electrodes and is electrically connected. For such fixing and conduction, the circuit board 19 uses the solder 20, and the overhang 13 a uses the anisotropic conductive film 21.

However, according to the TAB mode liquid crystal display device 11, the TAB 14 must be joined to the circuit board 19 and the overhang 13a by two types of members, and different connection methods must be adopted. However, this increases the number of processes and the number of parts, and as a result,
There is a problem that the manufacturing cost increases.

Further, the problem that the number of steps increases, the number of parts increases, and the manufacturing cost increases as described above.
The same can be said for the liquid crystal panel described in JP 23612B.

[0018]

According to the present invention, there is provided a display device according to the present invention, wherein a driving IC is disposed in a non-display area on a glass substrate having a display area defined in the X direction and the Y direction.
The end face of the glass substrate and the end face of the circuit board made of the multilayer wiring are connected so as to be in contact with each other, and the input wiring for the driving IC is formed on the circuit board, and the input wiring and the driving IC are connected to each other. An apparatus connected by wire bonding, wherein the glass substrate and the circuit board are fixed with an upper reinforcing plate on the side where a driving IC is provided, and the upper reinforcing plate is soldered to the circuit board. A circuit board provided corresponding to a driving IC arranged in the X direction;
The circuit boards provided corresponding to the driving ICs arranged in the directions are separated from each other, and the adjacent ends of these circuit boards are electrically connected to each other by FPC pieces.

According to a second aspect of the present invention, there is provided a display device according to the present invention, wherein an end face of a glass substrate having a display area defined in the X direction and the Y direction is connected to an end face of a circuit board made of multilayer wiring so as to abut. A device in which a driving IC is provided on a circuit board, an extraction electrode from a display area is formed in a non-display area of the glass substrate, and the extraction electrode and the driving IC are connected by wire bonding. A circuit board in which the glass substrate and the circuit board are fixed with an upper reinforcing plate on the side where the driving IC is provided, the upper reinforcing plate is soldered to the circuit board, and further provided in the X direction. And the circuit boards arranged in the Y direction are separated from each other, and the adjacent ends of these circuit boards are electrically connected to each other by FPC pieces.

[0020]

According to the display device of the present invention, a circuit board composed of multilayer wiring is arranged in parallel with the driving IC mounting board so that the end faces thereof are in contact with each other, and the driving IC mounting board is provided on the circuit board. Forming input wiring, input wiring and driving IC
And are connected by wire bonding.
According to the display device of the second aspect, a circuit board made of multilayer wiring is arranged in parallel so that end faces abut on the board, and a driving IC is arranged on the circuit board, and one of the boards is provided. In this configuration, an extraction electrode from the display area is formed in the non-display area, and the extraction electrode and the driving IC are connected by wire bonding.

In the case of both circuit boards arranged as described above, bus lines required for the driving IC are formed on this board, a power supply, a processing circuit, etc. are mounted, and various wirings are formed in multiple layers. It is possible to increase the width of these connection wirings while limiting the dimensions of the circuit board, and as a result, the overall width of the connection wirings and the area required for their routing can be reduced. With the miniaturization, the size of the liquid crystal display device can be reduced.

If necessary, for example, a connector, a capacitor, a resistor and the like can be directly mounted on the connection wiring on the circuit board.

In addition, as compared with a conventional liquid crystal display device provided with an FPC, a circuit board is arranged side by side so that end faces abut on a substrate in a display area without using an FPC. The problem caused by bending, that is, the poor electrical accuracy, is eliminated, and thus a highly reliable and high quality display device can be mass-produced.

Further, even when compared with a conventional liquid crystal display device having a TAB, the problem caused by mounting the TAB, that is, the TAB is connected to two kinds of members by different connection methods, thereby increasing the number of steps. However, the problem of an increase in the number of parts is eliminated, and as a result, manufacturing costs are reduced.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present embodiment will be described below by taking a liquid crystal display device as an example.

(Example 1) FIGS. 1 to 3 show a CO according to the first aspect.
FIG. 1 is a sectional view of a main part of the liquid crystal display device 22, FIG. 2 is an exploded view, and FIG. 3 is a perspective view.

According to these figures, reference numeral 23 denotes a segment-side glass substrate, and reference numeral 24 denotes a common-side glass substrate having an area smaller than that of the glass substrate 23.
The liquid crystal is sealed by the sealant 25 between 24, and the display area 26 is formed. A driving IC 27 is mounted in a non-display area of the glass substrate 23, and a glass epoxy substrate 28 (CEL-445A manufactured by Shin-Kobe Electric Co., Ltd.) is provided side by side so that end faces abut on the substrate 23. I do. The substrate 28 has a multilayer wiring structure in which one or more wiring layers can be formed inside the substrate. When the glass epoxy substrates 28 having such a multilayer wiring structure are juxtaposed, the glass substrate 23 and the glass epoxy substrate 28 The thickness of each plate is preferably substantially the same in order to maintain the fixing strength between them.

As a fixing means for this juxtaposition, there is a method of simply fixing the contact surface with an adhesive. Alternatively, as described later, a small piece is separately attached near the contact, and the reinforcing means is used. You may fix it with it. 29 is the glass substrate 2
These are connection wirings of electrodes arranged on the inner surfaces of Nos. 3 and 24.

It is preferable that the thermal expansion coefficients of the glass substrate 23 and the glass epoxy substrate 28 are substantially the same. When a normal plate glass is used for the glass substrate 23, the coefficient of thermal expansion is 8 to 9 × 10 ⁻⁶ / ° C., whereas the coefficient of thermal expansion of the glass epoxy substrate 28 is also 8 to 9 × 10 ^−6.
/ ° C. However, the coefficient of thermal expansion is 10 to 15 × 10 ⁻⁶ /
Use of another type of glass epoxy substrate 28 having a temperature of ℃ did not cause any problem. There are two types of driving ICs 27, an IC 27a in the X direction of the display area 26 and an IC 27b in the Y direction.
8a and 28b. The glass epoxy board 28a is a signal-side circuit board, and is a multi-layer board in which bus lines necessary for driving the IC 27a, power supplies, logic, and other systems are wired for each layer. Pads for wire bonding are arranged. The glass epoxy board 28b is a circuit board on the scanning side, and is a multilayer board on which bus lines necessary for driving the IC 27b and a circuit for processing various power supplies and signals supplied from the outside are mounted. Pads for wire bonding with each IC 27b are arranged. Further, terminals are provided in the vicinity of the glass epoxy substrate 28b of the two glass epoxy substrates 28a, and the terminals are connected to the glass epoxy substrate 28b. Then, the adjacent ends of the substrates 27 and 28 are electrically connected to each other by a jumper (small FPC piece) not shown.

The glass epoxy substrates 28a and 28b
The bus lines above are wire-bonded 30 to ICs 27a and 27b, respectively.
a, 27b are wire bonding 3 with connection wiring 29;
1 has been done. These wire bondings 30, 31
Is performed with a gold wire, and the corresponding bonding pad is surface-treated with gold, aluminum, or the like.

Thus, in the liquid crystal display device 22 of the present embodiment, the bus lines required for the driving IC 27 are formed on the glass epoxy substrate 28, and furthermore, each system such as a power supply and a logic is wired for each layer. Alternatively, the glass epoxy substrate 28 is provided with a multilayer substrate on which a processing circuit for various power supplies and signals supplied from the outside is mounted, whereby the glass epoxy substrate 28 can be reduced and the width of the connection wiring on the substrate 28 can be reduced. As a result, the size of the liquid crystal display device 22 can be reduced with the overall reduction in the width of the connection wiring and the area required for the routing. For example, it was experimentally confirmed that the size was reduced by about 20 mm in the X direction as compared with the conventional COG type liquid crystal display device.

In addition, as compared with a conventional liquid crystal display device provided with an FPC, no FPC is used, and therefore, a problem caused by bending the FPC, that is, a poor electrical accuracy can be solved.

Furthermore, the number of parts is reduced as compared with the conventional liquid crystal display device provided with a TAB, so that the number of steps is reduced, and as a result, the manufacturing cost is reduced.

The driving IC 2 is mounted on the glass substrate 23.
7, a highly reliable wire bonding 31 was achieved due to the surface smoothness of the substrate 23. Furthermore, since the connection wiring 29 does not extend to the end of the glass substrate 23, there is an advantage that the edge of the glass plate is not affected by cracks or cracks.

(Example 2) In a liquid crystal display device 32 according to a second embodiment of the present invention, as shown in FIG. The substrate 28 was used, and the other configuration was the same. In the figure, members having the same functions as those shown in FIGS. 1 to 3 are denoted by the same reference numerals.

Also in the liquid crystal display device 32 of this embodiment, the substrate 28 can be reduced by the glass epoxy substrate 28 as a multilayer substrate, and the width of the connection wiring on the substrate 28 can be increased. Has been achieved.

(Example 3) In this example, as shown in FIGS. 5 to 9, in the liquid crystal display device 22 in which the driving IC 27 is mounted on the glass substrate 23, the glass epoxy substrate 28 is arranged in parallel with the glass substrate 23. As the fixing means, a liquid crystal display device 33 fixed by this reinforcing means using a small piece or a glass epoxy plate made of, for example, carbon steel SS41 or S35C separately. 5 is a plan view of the liquid crystal display device 33, FIG. 6 is a front view thereof, FIGS. 7 and 8 are cross-sectional views of main parts of the liquid crystal display device 33, and FIG. It is a perspective view. In the figure, the same parts as those shown in FIGS. 1 to 3 are denoted by the same reference numerals.

FIG. 7 shows a configuration in which a lower reinforcing plate 35 (for example, a glass epoxy plate) is attached via an adhesive layer 34 such as a double-sided tape to fix the glass epoxy substrate 28a.

The lower reinforcing plate 35 is a strip-shaped plate, and the size of the short side is such that the glass epoxy substrate 28a is fixed to the glass substrate 23, and that it does not reach the display area of the substrate 23. To decide. The longitudinal dimension may be about the entire length of the glass epoxy substrate 28a. The thickness of the plate 35 may be at most 1 mm, for example, 0.3 mm.

FIGS. 8 and 9 show a structure in which the glass substrate 23 and the upper reinforcing plate 37 are fixed via an adhesive layer 36 such as a thermosetting adhesive. The glass epoxy board 28b and the upper reinforcing plate 37 are fixed via an adhesive layer 36 such as solder. In addition, this soldering makes it easy to remove the glass epoxy board 28b, and the board 28b can be reused.

When the glass epoxy substrate 28 is fixed by the reinforcing plates 35 and 37 as described above, the structure shown in FIGS. 5 and 6 is obtained. In FIG. 5, the above-mentioned jumper (small FPC piece for electrically connecting the adjacent ends of the boards 27 and 28) is illustrated by reference numeral 38, and 39 is a connector.

As for the lower reinforcing plate 35, the driving IC 27
Since the width of the non-display area serving as the array surface of the IC a is relatively small (for example, 5 mm or less), and in order to protect the wire bonding 30 and 31 of the IC 27a, this IC is used.
In order to avoid the influence of this sealing step, a lower reinforcing plate 35 is attached to the back side of the glass substrate 23 to seal the sealing 27a with a resin.

The upper reinforcing plate 37 has a drive I
Since the width of the non-display area serving as the array surface of C27b is relatively wide (for example, 10 mm or more), the upper reinforcing plate 37 is attached to the upper side of the glass substrate 23 so as not to be affected by insertion and removal of the connector 39 and the like. . Such an upper reinforcing plate 37 is preferably formed of a highly rigid metal or a heat-resistant resin.

Thus, in the liquid crystal display device 33 of the present embodiment, each reinforcing plate 3 is different from the liquid crystal display device 22 of (Example 1).
It was firmly fixed with 5, 37, and thereby high reliability was obtained over a long period of time.

In addition, the present inventor employed a glass epoxy board as a circuit board as an example. In addition, a circuit board such as a BT resin board, an aramid fiber reinforced epoxy board, a board in which FPC is reinforced from the back side with a glass epoxy, a ceramic board, etc. It was experimentally confirmed that the same operation and effect were obtained even when the substrate was provided in parallel with the glass substrate 23.

The present invention is not limited to the liquid crystal display device as in the above embodiment, but can be applied to various display devices such as plasma and EL. In addition to this embodiment, various changes and improvements can be made without departing from the scope of the present invention.

For example, in this embodiment, two glass epoxy substrates 28a and one glass epoxy substrate 2
8b, one glass epoxy substrate 28a and one glass epoxy substrate 28
b, or may be collectively formed by one glass epoxy substrate 28.

Further, the mounting surface of the driving IC 27 on the glass substrate 23 or the glass epoxy substrate 28 may be the back surface on the side shown in the above embodiment.

The means for fixing the glass substrate 23 and the glass epoxy substrate 28 is not limited to the above-mentioned example, and may be juxtaposed by any other desired method.

[0050]

As described above, according to the display device of the first aspect, a circuit board composed of multi-layer wiring is continuously connected to the drive IC mounting board so that the end faces thereof are in contact with each other. In this configuration, the input wiring for the driving IC is formed, and the input wiring and the driving IC are connected by wire bonding. Further, according to the display device of the second aspect, a circuit board made of multilayer wiring is continuously provided so that end faces abut on the board, a driving IC is provided on the circuit board, and a non- In this configuration, an extraction electrode from the display area is formed in the display area, and the extraction electrode and a driving IC are connected by wire bonding.

According to these two inventions, it is possible to increase the width of the connection wiring while limiting the size of the circuit board, thereby reducing the overall width of the connection wiring and the area required for its routing. With the miniaturization, the miniaturization of the liquid crystal display device could be achieved. Further, if necessary, for example, a connector, a capacitor, a resistor and the like could be directly mounted on the connection wiring on the circuit board.

Further, according to the present invention, a display device having high reliability and high quality can be mass-produced and a manufacturing cost can be reduced as compared with a display device provided with a conventional FPC or a display device provided with a TAB. did.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a liquid crystal display device according to an embodiment.

FIG. 2 is an exploded view of the liquid crystal display device of the embodiment.

FIG. 3 is a perspective view of the liquid crystal display device of the embodiment.

FIG. 4 is a sectional view of a main part of a liquid crystal display device according to another embodiment.

FIG. 5 is a plan view of a liquid crystal display device of still another embodiment.

FIG. 6 is a front view of a liquid crystal display device according to still another embodiment.

FIG. 7 is a sectional view of a main part of a liquid crystal display device according to still another embodiment.

FIG. 8 is a sectional view of a main part of a liquid crystal display device according to still another embodiment.

FIG. 9 is a perspective view of a main part of a liquid crystal display device according to still another embodiment.

FIG. 10 is a plan view of a main part of a conventional liquid crystal display device.

FIG. 11 is a sectional view of a main part of a conventional liquid crystal display device.

[Description of sign]

 Reference Signs List 23 glass substrate 26 display area 27 driving IC 28 glass epoxy substrate 29 connection wiring 30, 31 wire bonding 35 lower reinforcing plate 37 upper reinforcing plate

Claims (2)

(57) [Claims] A driving IC disposed in a non-display area on a glass substrate having a display area defined in an X direction and a Y direction;
The end face of the glass substrate and the end face of the circuit board composed of the multilayer wiring are connected so as to be in contact with each other, the input wiring for the driving IC is formed on the circuit board, and the input wiring and the driving IC are connected by wires. A display device connected by bonding, wherein the glass substrate and a circuit board are
At the installation side of the drive IC, fix it with the upper reinforcing plate.
A circuit board provided by soldering the upper reinforcing plate to the circuit board, and further provided for a driving IC arranged in the X direction;
A circuit board provided corresponding to the driving IC arranged in the Y direction is separated, and the adjacent ends of these circuit boards are separated by FPC.
A display device characterized in that it is electrically connected to one side. 2. A driving IC is provided on a glass substrate having a display area defined in an X direction and a Y direction so that an end surface of a glass substrate having a display area defined in the X direction and the Y direction is in contact with an end surface of a circuit substrate formed of multilayer wiring. A display electrode formed from a display area in a non-display area of the glass substrate, and the extraction electrode and a driving IC are connected by wire bonding, wherein the glass substrate and the circuit board are connected to each other.
At the installation side of the drive IC, fix it with the upper reinforcing plate.
The upper reinforcing plate is soldered to the circuit board, and the circuit board arranged in the X direction and the circuit board arranged in the Y direction are separated. A display device characterized in that the display device is electrically connected.