JP3199570B2 - 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 a display device having a display area of liquid crystal, plasma, EL or the like.

[0002]

2. Description of the Related Art A display device has an I / O for driving it.
C is provided, and various methods of mounting the driving IC have been proposed. Taking a liquid crystal display device as an example,
A method in which a driving IC is mounted on a film substrate, and the IC mounting film substrate is bonded to a display substrate, so-called TAB.
-Type liquid crystal display devices have been proposed (Japanese Utility Model Laid-Open No. 3-11).
No. 4820).

Hereinafter, a TAB mode liquid crystal display device 1 will be described with reference to FIGS. 8 and 9. FIG. 8 shows a TAB mode liquid crystal display device 1.
9 is a cross-sectional view taken along the line AA of FIG. 8.

According to the TAB mode liquid crystal display device 1, a liquid crystal is sealed between the upper glass substrate 2 and the lower glass substrate 3 to form a display area 4, and the inner surfaces of the upper and lower glass substrates 2, 3 are respectively provided. The display electrodes 5 and 6 are arranged so as to be orthogonal to each other,
These display electrodes 5 and 6 are connected to a lead wire 7 on the lower glass substrate 3. When the X direction is displayed along the long side of the display area 4 and the Y direction is displayed along the short side, a plurality of film substrates 8 made of polyimide are formed along both directions.
a and 8b are arranged. These film substrates 8a,
8b, one driving IC 9a, 9b is mounted, respectively, and further connected to a copper foil wiring 10 provided in each substrate 8a, 8b. In addition, these film substrates 8a, 8b
Includes a long bus line circuit board 11a,
11b is connected. 12 is a film substrate 8a, 8
b, an anisotropic conductive film for electrically connecting the copper foil wiring 10 and the lead-out wiring 7; 13 is a film substrate 8a, 8b
And the wiring of the circuit boards 11a and 11b.

[0005]

However, in the liquid crystal display device 1 having the above-mentioned structure, the copper wiring 10 and the lead wiring 7 on the film substrates 8a and 8b are not connected to the anisotropic conductive film 12.
It is difficult to reduce the electrode terminal pitch of the anisotropic conductive film 12 to less than about 100 μm. It is no longer compatible with the tendency to narrow the pitch.

In this color liquid crystal display device, 100 μm
10 m or less (for example, 77 μm), the driving ICs 9 a and 9 b must extend along the longitudinal direction. For this reason, the film substrate 8 a located at the end is not shown in FIG. As shown in the figure, it is necessary to route the lead wiring 7 in an oblique direction. As a result, the area for mounting the film substrate 8a is enlarged, and the display area 4
This film substrate 8a is mounted at a position deviated from the dimension area in the X direction (longitudinal direction), which causes a problem of increasing the size.

When the film substrate 8a deviates from a desired position as described above, it is only necessary to extend the lead-out wiring 7 for a long time, the distance between the individual lines becomes small, the production becomes difficult, and the production yield becomes low. In addition, at the level of liquid crystal technology, the resolution of photolithography and the pattern rules for mass production will be exceeded.
In some cases, a pattern cannot be designed, and it cannot be practically manufactured.

In order to solve the above problem, as shown in FIG. 8, in a configuration in which driving ICs 9a are arranged in the X direction above and below a display area 4, pixel electrodes are alternately arranged line by line. It has been proposed that the display area 4 be divided into upper and lower parts and the upper and lower divided planes be separately driven. Therefore, there is a problem that desired display quality cannot be obtained.

Furthermore, a technique for reducing the pitch of the conductive connecting portions of the anisotropic conductive film 12 to less than about 100 μm has been developed. However, a highly reliable fine pitch anisotropic conductive film which is still satisfactory. There is no current situation.

[0010]

[Means for Solving the Problems] The display device of the present invention comprises:
A plurality of film substrates each having a driving IC mounted thereon are arranged in a non-display area on a transparent substrate having a square or rectangular display area, and a plurality of connections are made to electrically conduct between the driving ICs. A circuit board having lines is arranged side by side on a transparent substrate, and the plurality of driving ICs are arranged obliquely along the sides of the display area, and each connection line of the film substrate and a pixel electrode of the display area are arranged. It is characterized by being arranged so that the electrical connection with the line is substantially the same as the arrangement direction of the driving ICs.

[0011]

According to the display device having the above-described structure, the driving ICs mounted on the film substrate are arranged obliquely along the sides of the display area. When electrically connecting the pixel electrode lines, the connection lines between them are also arranged so as to be oblique along the sides of the display area. In order to reduce the pitch of the electrodes, the electrode arrangement is not directly and shortly connected to the connection lines of the film substrate, and the connection lines are obliquely arranged on the film substrate (the pitch of the conductive connection portions of the connection lines is around 100 μm). And a circuit board comprising a plurality of connection lines for electrically connecting between the driving ICs while rotating the lead wires from the display electrodes. Since it is provided in common between the film substrates, a space for the connection line is not required, and as a result, the pitch of the display electrodes can be narrowed due to the colorization and high definition of the display device, and the device can be used. Can be reduced in size. Moreover, even if the drawing wiring from the display electrode is routed, there is no need to reduce the distance between the individual lines.
As a result, the manufacturing is facilitated, the manufacturing yield is improved, and as a result, a low-cost, high-quality and highly reliable display device can be provided.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present embodiment will be described below by taking a color liquid crystal display device having a color filter as an example. (Example 1) FIGS. 1 to 7 show a TAB type liquid crystal display device 14 according to the present invention, FIG. 1 is a plan view of the TAB type liquid crystal display device 14, and FIG. It is sectional drawing by B. FIG. 3 shows a TAB mode liquid crystal display device 14.
FIG. 4 is a configuration diagram of a display electrode. Also,
FIG. 5 shows a drawing wiring pattern of the display electrode, and FIG. 6 shows another drawing wiring pattern. FIG. 7 shows a main part of the arranged film substrates.

In these figures, reference numeral 15 denotes a glass substrate on the segment side, and reference numeral 16 denotes a glass substrate on the common side having a smaller area than the glass substrate 15. The liquid crystal 18 is sealed, and a display area 19 is formed. This display area 19
Is a rectangle, and the direction along the long side is indicated as X direction, and the direction along the short side is indicated as Y direction. This display area 1
On the inner surface of each of the substrates 15 and 16 corresponding to 9, many display electrodes 20 a and 20 b made of a transparent conductor such as ITO are arranged so as to be orthogonal to each other between the substrates, and these display electrodes 20 a and 20 b Is connected to the lead wiring 21 on the glass substrate 15.

The display electrodes 20a arranged in the Y direction on the glass substrate 15 are signal electrodes, and the display electrodes 20b arranged in the X direction on the glass substrate 16 are scanning electrodes. Red (R), green (G),
In order to make each of the blue (B) electrode lines one set, the display electrode 2
The number of electrodes 0a is three times as large as that of the display electrode 20b.
In the case of a color liquid crystal display device, a color filter or the like is formed, but is omitted from the drawing.

A display area 19 is provided on the glass substrate 15.
A plurality of film substrates 22a made of polyimide are regularly arranged along both sides in the X direction, and a plurality of film substrates 22b made of polyimide are regularly arranged along the Y direction of the display area 19. Substrate 22
a and 22b respectively have one driving IC 23a, 2
3b is mounted and connected to the copper foil wirings 24a and 24b on the film substrates 22a and 22b. The film substrates 22a and 22b are connected to long circuit boards 25a and 25b for bus lines, respectively.
Reference numeral 26 denotes an anisotropic conductive film for electrically connecting the copper foil wirings 24a and 24b to the lead-out wiring 21, and 27 electrically connects the wiring of the film substrates 22a and 22b to the connection lines of the circuit boards 25a and 25b. Solder.

Each of the circuit boards 25a and 25b has, for example, a multilayer wiring structure in which one or two or more wiring layers can be formed inside the substrate, or a structure in which wiring layers are formed on both main surfaces. , 23b, a bus line group having a power supply and a signal line necessary for driving the power supply and a signal line, and further, if necessary, wiring each system such as a power supply, a logic, and the like, or various types supplied from the outside. A multilayer substrate on which a power supply and a signal processing circuit are mounted may be provided.

The substrate material of the circuit boards 25a and 25b includes, for example, a glass epoxy board, a BT resin board, an aramid fiber reinforced epoxy board, a board in which FPC is reinforced from the back with a glass epoxy, and a ceramic board.

Further, with respect to the shape of the film substrate 22a, the driving ICs 23a are arranged obliquely along the sides of the display area 19, and the row direction of the conductive connecting portions of the anisotropic conductive film 26 is set to the driving IC 23a. Are substantially parallel to the longitudinal direction, and the rows of the solders 27 are determined so as to be linear in order to electrically connect one electrode terminal of each driving IC 23a to the common circuit board 25a.

Furthermore, regarding the electrical connection state to the driving IC 23a, electrode pads are arranged on the driving IC 23a along both sides in the longitudinal direction, and one electrode pad is connected to the copper foil wiring 24a. Face-bonded so as to individually correspond to the display electrode 20a through the conductive connection portion of the anisotropic conductive film 26, and the other electrode pad is also connected to the wiring on the film substrate 22a. It is face-bonded and electrically connected to the connection line of the circuit board 25a via the solder 27.

Next, the state of electrical connection to the film substrate 22a will be described with reference to FIGS. 3 and 5. In this embodiment, one driving IC 23a is connected to a predetermined number of lead-out wires 21. The corresponding overall length Lt of the anisotropic conductive film 26 of the circuit board 25a in the conductive connection column direction is longer than the corresponding overall length Ld of the arrangement width of the lead-out wires 21 (Lt> Ld).
When an angle between the side of the display area 19 along the X direction and the longitudinal direction of the driving IC 23a is θ, it is preferable that the angle θ be set to a value equal to or more than COS ⁻¹ (Ld / Lt). , Optimally substantially θ = COS ⁻¹ (Ld / L
t).

Thus, according to the TAB mode liquid crystal display device 14 having the above configuration, the driving IC 23a is
Are arranged obliquely with respect to the side along the direction, whereby the lead-out wiring 21 is connected to the anisotropic conductive film 2 of the circuit board 25a.
6 without being directly and shortly connected in the row direction, the conductive connection portions of the anisotropic conductive film 26 (pitch P about 100 μm) are effectively turned around the diagonally arranged anisotropic conductive film 26. ) Connection. In addition, since the circuit board 25a is arranged in parallel with the glass substrate 15 and the film substrate 22a is provided so as to straddle the circuit board 25a and the glass substrate 15, the circuit board 25a can be made compact and the connection wiring inside the circuit board 25a can be reduced. The width can be increased, and the non-display area of the liquid crystal display device 14 is reduced with the overall reduction in the width of the connection wiring and the area required for routing the connection wiring.
4 could be downsized.

Further, even if the lead wiring 21 is routed,
There is no need to reduce the distance between the individual lines, thereby facilitating the production and improving the production yield. As a result, the low-cost, high-quality and highly reliable liquid crystal display device 14 is manufactured.
Could be provided.

According to an experiment repeatedly performed by the present inventors,
When an STN color liquid crystal display device 14 having a pitch of the display electrodes 20a of 0.077 mm is designed using a dedicated driver with 160 outputs as the driving IC 23a, the optimum angle of θ is 31.2 degrees. Was.

In the above embodiment, W shown in FIG.
1, that is, the film substrate 22 extending over the area of the copper foil wiring 24a of the film substrate 22a and the arrangement area of the driving IC 23a
Among the sides of “a”, the side extending over the region of the lead-out wiring 21 of the adjacent film substrate 22a is preferably small so as not to interfere with the adjacent film substrate 22a.

That is, as shown in FIG. 7, when arranging a plurality of film substrates 22a, the distance W4 from the corner P of the film substrate 22a to the side of the glass substrate 15 and the film width of the distance W4 In addition to the distance W5 occupied by the substrate 22a, at the intersection M between the line extending from the corner P to the side of the glass substrate 15 and the oblique side S of the adjacent film substrate 22a, the intersection M of the distance W4 In the case where the interval W6 is reached, the relational expression between W4, W5, and W6 may be set to W4> W5 + W6.

Further, W2 shown in FIG. 3, that is, the side along the 27 rows of the solder among the sides of the film substrate 22a is:
It is preferable to make the size small enough not to interfere with the adjacent film 22a (Ld ≧ W2).

Further, in the above embodiment, as shown in FIG.
6 are set to be substantially the same, but the conductive connecting portions of the anisotropic conductive film 26 are staggered as shown in FIG. The dimensions W3 of the bending portions may be alternately arranged to be longer and shorter.

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.

[0029]

As described above, according to the display device of the present invention, the drive IC mounted on the film substrate and the connection line between the connection line of the film substrate and the pixel electrode line in the display area are formed. Arranged diagonally along the side of the display area, this allows connection while effectively turning the lead wires from the display electrodes, and furthermore, the circuit board is provided in common between the film substrates, and as a result, In addition, the pitch of the display electrodes has been narrowed in accordance with the colorization and high definition of the display device, and the device has been reduced in size. Furthermore, according to the display device of the present invention, even if the lead-out wiring from the display electrode is routed, it is not necessary to reduce the distance between the individual lines, thereby facilitating the production and improving the production yield. A low-cost, high-quality and highly reliable display device can be provided.

[Brief description of the drawings]

FIG. 1 is a plan view of a liquid crystal display device according to an embodiment.

FIG. 2 is a cross-sectional view of a main part of the liquid crystal display device of the embodiment.

FIG. 3 is an enlarged view of a main part of the liquid crystal display device of the embodiment.

FIG. 4 is a configuration diagram of a display electrode of the color liquid crystal display device.

FIG. 5 is an explanatory diagram of a lead wiring pattern.

FIG. 6 is an explanatory diagram of a lead wiring pattern.

FIG. 7 is an enlarged view of a main part of the film substrate.

FIG. 8 is a plan view of a conventional liquid crystal display device.

FIG. 9 is a sectional view of a main part of a conventional liquid crystal display device.

FIG. 10 is an explanatory diagram of a lead wiring pattern for a film substrate.

[Description of sign]

 15, 16 Glass substrate 19 Display area 20a, 20b Display electrode 21 Lead wiring 22a, 22b Film substrate 23a, 23b Driving IC 24a, 24b Copper foil wiring 25a, 25b Circuit board 26 Anisotropic conductive film

Claims (1)

(57) [Claims] 1. A plurality of film substrates each having a driving IC mounted thereon are arranged in a non-display region on a transparent substrate having a square or rectangular display region, and each driving IC
A circuit board having a plurality of connection lines is provided side by side on a transparent substrate so as to electrically connect between them, and the plurality of driving ICs are arranged obliquely along the sides of the display area, and A display device, wherein electrical connection between each connection line of a film substrate and a pixel electrode line in a display area is arranged in substantially the same direction as the arrangement direction of the driving ICs.