JP3199564B2 - 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 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 have been proposed as means for providing the driving IC. As one example, there is a bare chip mounting of an IC, according to which a wiring on a substrate and the IC are connected by wire bonding.

The above proposal will be described with reference to FIGS. 9 to 12 by taking a COG type liquid crystal display device as an example (Japanese Patent Laid-Open No. Hei 4-3672).
No. 7). 9 is a plan view of the COG liquid crystal display device 1, FIG. 10 is a front view, and FIG. 11 is a side view.
FIG. 12 is a partially enlarged view.

[0004] Reference numeral 2 denotes an upper glass substrate and reference numeral 3 denotes a lower glass substrate having a size larger than that of the upper glass substrate 2. A liquid crystal is sealed between the upper and lower glass substrates 2 and 3 to form a display area 4. The display area 4 forms a rectangle, and the direction along the long side is displayed as the X direction, and the direction along the short side is displayed as the Y direction. In a region other than the display region 4 of the lower glass substrate 3, a plurality of long driving ICs 5a are arranged along the X direction, and a plurality of long driving ICs 5b are arranged along the Y direction. Arrange.

[0005] On the inner surfaces of the substrates 2 and 3 located in the display area 4, a number of display electrodes made of a transparent conductor are arranged so as to be orthogonal to each other between the two substrates. It is connected to the lead wiring 6 on the substrate 3. Reference numeral 7 denotes a signal input line group for driving each driving IC 5a, a so-called bus line.

The driving ICs 5a and 5b have electrode pads arranged along the longitudinal direction thereof, and these electrode pads are individually connected to the lead wiring 6. One driving IC 5a, 5b is connected to a predetermined number of lead wires 6, and the one driving I
The total length Lp of the C electrode pad array is smaller than the total length Ld of the corresponding array of the lead-out lines 6 (Lp> Ld).

[0007]

However, in the recent COG type liquid crystal display device 1, the pitch of each display electrode tends to become narrower with the development of color and higher definition. On the other hand, the driving ICs 5a, 5b The pitch of the electrode pads is about 100 μm, so that the narrowing of the display electrode pitch and the actual electrode pad pitch have become incompatible.

That is, when Lp> Ld, if the difference between the two is small, this problem becomes remarkable.
Even if the pitch narrows to such an extent that p <Ld, the driving ICs 5a and 5b must extend along the longitudinal direction. Therefore, of the driving ICs 5a arranged in a straight line, the driving I
In C5a, as shown in FIG.
Had to be routed diagonally. As a result, the area for mounting the driving IC 5a is enlarged, and the X
There is a problem that the device is mounted on the driving IC 5a at a position deviating from the dimension area in the direction (longitudinal direction), resulting in an increase in size. Also, the driving IC 5a
Is deviated from a desired position, the lead-out wiring 6 is simply extended for a long time, which is inferior in practicality.

Further, as shown in FIG. 13, when the lead-out wirings 6 are routed, the spacing between the individual lines becomes small, the production becomes difficult, the production yield decreases, and the resolution of photolithography at the level of liquid crystal technology is increased. In some cases, the design exceeds the limits of pattern rules in mass production and the like, making it impossible to design a pattern, and in some cases, manufacturing is impossible.

To solve such a problem, FIG.
As shown in (1), a configuration is also proposed in which the driving ICs 5a are arranged in the X direction above and below the display area 4, and the pixel electrodes are alternately drawn out line by line to the upper driving IC 5a and the lower driving IC 5a. However, according to this proposal, the inside of the display area 4 is divided into upper and lower parts, and the upper and lower divided planes cannot be driven separately, so that a desired display quality cannot be obtained. There is.

[0011] The applicant of the present invention is disclosed in Japanese Unexamined Patent Publication No. Hei.
According to No. 8, in the COG type liquid crystal display device 1, the bus line 7 is constituted by a multilayer wiring board in which wiring layers and insulating layers are alternately laminated, whereby a space for two-dimensional wiring is reduced. Although a small liquid crystal display device was proposed, the pitch of each display electrode tends to be narrower with colorization and higher definition in the liquid crystal display device of this configuration. There is a problem that the actual electrode pad pitch does not match.

[0012]

[Means for Solving the Problems] The display device of the present invention comprises:
In a non-display area on a substrate having a square or rectangular display area, a plurality of driving ICs and a circuit board having a plurality of connection lines for electrically connecting between the driving ICs are arranged. The plurality of driving ICs are arranged and arranged on a circuit board and / or on the substrate in a diagonal direction along a side of the display area, and are electrically connected to pixel electrode lines of the display area and connection lines of the circuit board. It is characterized by having.

[0013]

According to the display device having the above structure, a plurality of driving ICs arranged in the non-display area on the substrate are arranged so that their longitudinal directions are oblique to the sides of the display area. ,
This eliminates the need to connect the electrode array directly and shortly to the driving IC in response to the trend of narrowing the pitch of each display electrode accompanying the recent trend toward colorization and high definition. A connection with a driving IC having a pitch of about 100 μm between electrode pads can be made while turning a lead wire from a display electrode near the IC. In addition, since the plurality of driving ICs are provided on a circuit board including a plurality of connection lines for electrically connecting the respective driving ICs, and / or on the board (for example, when there is a concave portion). By providing the driving IC on the circuit board), a small display device can be provided.

Furthermore, 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.
As a result, a low-cost, high-quality and highly reliable display device can be provided.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present embodiment will be described below by taking a color liquid crystal display device as an example. 1 to 7 show a COG type color liquid crystal display device 8 according to the present invention. FIG. 1 is a plan view of the COG type liquid crystal display device 8, and FIG.
B is a cross-sectional view, and FIG.
FIG. 4 is an enlarged view of a main part of a portion indicated by S in FIG. 1, FIG. 5 is a side view of a main part of the liquid crystal display device 8 shown in FIG. 4, and FIG. FIG. 7 is a view showing a circuit board 9 mounted with a driving IC.

According to these figures, reference numeral 10 denotes a glass substrate on the segment side, and 11 denotes a glass substrate on the common side having a smaller area than the glass substrate 10, and a sealing agent is provided between the glass substrates 10 and 11. The liquid crystal 13 is enclosed by 12 and a display area 14 is formed. This display area 14
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 10 and 11 corresponding to 4, many display electrodes 15 a and 15 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 15 a and 15 b Is connected to the lead wiring 16 on the glass substrate 10. The lead wiring 16 is made of ITO
And a metal layer such as aluminum is laminated on a transparent conductor layer such as.

The display electrodes 15a arranged in the Y direction on the glass substrate 10 are signal-side electrodes, and the display electrodes 15b arranged in the X direction on the glass substrate 11 are scanning-side electrodes. In order to make each of the red (R), green (G), and blue (B) electrode lines one set,
The number of electrodes a is three times that of the display electrodes 15b. still,
In the case of a color liquid crystal display device, a color filter or the like is formed, but is omitted in the drawing.

In the non-display area of the glass substrate 10, the driving I
Circuit boards 9 and 18 for mounting C17a and 17b
(For example, a glass epoxy board (CEL-445A manufactured by Shin Kobe Electric Co., Ltd.) having a thickness of 0.2 mm is mounted, and the circuit board 9 has a structure in which an IC mounting area 19 is formed in a protruding manner as shown in FIG. Each of the circuit boards 9 and 18 has a multilayer wiring structure in which one or more wiring layers can be formed inside the boards, or a structure in which wiring layers are formed on both main surfaces, and includes driving ICs 17a and 17b. The bus lines that have the power supply and signal lines necessary for driving the power supply are wired, and if necessary, the power supply, logic and other systems are wired for each layer, or various power supplies and A multi-layer substrate on which a signal processing circuit is mounted may be provided, and the glass substrate 1 may be provided via a thermosetting adhesive.
It is fixed on 0. When performing this thermal bonding, the difference in the coefficient of thermal expansion between the circuit board 9 and the glass substrate 10 is 10 ppm /
It is better to set the temperature below ° C.

In this embodiment, the circuit boards 9, 1
8 is fixed on the glass substrate 10 and then the circuit board 9 is fixed.
The driving IC 17a is die-mounted on the IC mounting area 19, and the other driving IC 17b is arranged side by side along the longitudinal side surface of the circuit board 18, and a plurality of long driving ICs 17a are arranged along the X direction. In addition, a plurality of long driving ICs 17b are arranged along the Y direction.

Next, the mounting state of the driving IC 17a is shown in FIG.
This will be described with reference to FIGS. This driving IC 17
a has an output electrode pad 20 along its longitudinal direction.
And electrode pads 21 for input are arranged, and the electrode pads 20 are wire-bonded and connected so as to individually correspond to the lead-out wirings 16, and the other electrode pad 21 is connected to the electrode pads arranged on the circuit board 9. Wire bonding connection. Then, a predetermined number of lead wires 1
6, one driving IC 17a is connected, and the total length Lp of the electrode pad array of the one driving IC 17a is
Is the total length Ld of the arrangement of the lead wirings 16 corresponding thereto.
(Between Po and Pn of the display electrode 15a) (Lp> Ld).

In these figures, the display area 14
The angle between the side along the X direction and the longitudinal direction of the driving IC 17a is θ, the effective width of the electrode pad region on the circuit board 9 is W1, the short side length of the driving IC 17a is W2,
Assuming that the effective width of the pad area on the lead-out wiring 16 is W3, this angle θ is defined as SIN ⁻¹ ｛(W1 + W2 + W3) /
It is preferable to set the value to be equal to or more than Ld｝, and optimally, substantially θ = SIN ^-1 {(W1 + W2 + W3) / Ld}.

Thus, according to the COG type liquid crystal display device 8 having the above structure, the longitudinal direction of the driving IC 17a is obliquely arranged with respect to the side of the display area 14 along the X direction, thereby connecting the lead wiring 16 to the driving IC 17a. Driving ICs 17 in an oblique array without connecting directly and shortly to
The connection with the electrode pad 20 (pitch around 100 μm) on the driving IC 17a was made while effectively turning to the vicinity of “a”. Moreover, since the driving IC 17a is provided on the circuit board 9, the size of the driving IC 17a itself can be reduced, and the width of the connection wiring therein can be increased. The non-display area of the liquid crystal display device 8 became smaller with the overall reduction in size, and as a result, the liquid crystal display device 8 could be downsized.

Further, even when the lead-out wirings 16 are routed, it is not necessary to reduce the distance between the individual lines, thereby facilitating the production and improving the production yield. As a result, low cost, high quality and high cost are achieved. Reliable liquid crystal display 8
Could be provided.

According to an experiment repeatedly performed by the present inventors,
When an STN color liquid crystal display device 8 in which a dedicated driver having 128 outputs is used as the driving IC 17a and the pitch of the display electrodes 15a is 0.077 mm is designed,
The optimum angle of the above θ was 31 degrees.

In the above embodiment, the driving IC
17a is provided on the circuit board 9, but as another embodiment, as shown in FIG.
Of the liquid crystal display device 8
The same operation and effect were obtained when the same was used. As still another example, the configuration of FIG. 7 and the configuration of FIG. 8 may be combined.

The present inventor employed glass epoxy boards for the circuit boards 9 and 18, but also used a BT resin board, an aramid fiber reinforced epoxy board, a board whose FPC was reinforced with a glass epoxy from the back, a ceramic board, or the like. I think it is OK.

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, the driving ICs 17a related to the circuit board 9 are arranged diagonally, but the driving ICs 17b may be similarly arranged diagonally for the circuit board 18.

[0028]

As described above, according to the display device of the present invention, a plurality of driving ICs arranged in a non-display area on a substrate are provided.
Are arranged such that the longitudinal direction is oblique to the sides of the display area, and thereby, the lead wires from the display electrodes are turned around the driving ICs in the oblique arrangement, thereby forming the electrode pads. A plurality of driving ICs can be connected to a driving IC having a pitch of about 100 μm, and the plurality of driving ICs are provided on a circuit board including a plurality of connection lines for electrically connecting the driving ICs. Alternatively, the driving IC is inserted into a circuit board having a concave portion, and as a result, the size of the display device can be reduced.

Further, according to the display device of the present invention, even if the lead-out wiring from the display electrode is routed, the individual line spacing becomes relatively large, thereby facilitating the production and improving the production yield. As a result, 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 partial cross-sectional view of the liquid crystal display device of the embodiment.

FIG. 3 is a plan view of a circuit board.

FIG. 4 is an enlarged view of a main part of the liquid crystal display device of the embodiment.

FIG. 5 is a side view of a main part of the liquid crystal display device of the embodiment.

FIG. 6 is a schematic view of an arrangement structure of display electrodes.

FIG. 7 is a perspective view showing a driving IC mounted state on a circuit board.

FIG. 8 is a perspective view showing a state where driving ICs are arranged side by side on a circuit board.

FIG. 9 is a plan view of a conventional liquid crystal display device.

FIG. 10 is a front view of a conventional liquid crystal display device.

FIG. 11 is a side view of a conventional liquid crystal display device.

FIG. 12 is an enlarged view of a main part of a conventional liquid crystal display device.

FIG. 13 is an enlarged view of a main part, showing a state in which a lead wiring is led to a driving IC.

[Description of sign]

 10, 11 Glass substrate 15a, 15b Display electrode 16 Lead wiring 17a, 17b Driving IC 9, 18 Circuit board 20, 21 Electrode pad

Claims (1)

(57) [Claims] A non-display area on a substrate having a square or rectangular display area, a circuit board having a plurality of drive ICs and a plurality of connection lines for electrically connecting the respective drive ICs; And the plurality of driving ICs are arranged and arranged on the circuit board and / or the board in a diagonal direction along the side of the display area, and are connected to the pixel electrode lines of the display area and the connection lines of the circuit board. A display device which is electrically connected.