JP2001228805A - Planar display device and printed circuit board used for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plane display device, which is connected with a connecting pad group 10 of a printed circuit board 1 and a terminal group 20 of a tape carrier package(TCP) 2 and the printed circuit board 1 for this purpose and to provide such planar display device and printed circuit board, which can shorten the working time for soldering and can easily and visually decide as to whether clamping pad parts 11 at both ends of the connecting pad group 10 are subjected sufficiently to soldering. SOLUTION: The clamping pad parts 11, at both ends of the connecting pad group 10, are separated and formed to clamping pads 12 and 13 on a substrate inner and substrate end side. The clamping pads 13 on the end side of the substrate are provided with overhanging parts 13a so that fillets 41 of solders 4 are formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a flat display device such as a liquid crystal display device, and a drive input printed wiring board used for the flat display device. In particular, the input terminal group of the Tape Carrier Package (TCP)
The present invention relates to a device in which connection pads of a drive input printed wiring board are connected by soldering.

[0002]

2. Description of the Related Art In a flat display device such as a liquid crystal display device for displaying an image, which performs a matrix display, a connection terminal portion connected to a drive input system is generally provided on a peripheral portion of a display panel. A drive IC chip is directly mounted on this connection terminal portion and connected to a terminal group on the lower surface (COG: Chip).
On Glass) or TCP with driver IC chip
(OLB: Outer Lead Bond)
ing). In the case of the OLB system, the input side terminal group of each TCP is connected to the connection pad group of the driving printed wiring board, whereby the TCP
, A drive input signal is input to the display panel.

The connection between the input terminal group of the TCP and the driving printed circuit board according to the prior art will be described with reference to FIG.

[0004] A plurality of TCPs 2 are connected to the peripheral connection portion 31 of the display panel main body 3 via an ACF (anisotropic conductive film) or the like. A drive IC 25 is mounted substantially at the center of each TCP 2.

[0005] On the upper surface of the driving printed wiring board 1, there are provided connection pad groups 10 for connecting to the input terminal groups 20 of the respective TCPs 2. The connection between the connection pad group 10 and the output-side terminal group 20 of TCP2 is
This is performed by soldering.

[0006] As shown in the figure, connection pads 11 'located at both ends of a connection pad group 10 are connected to other connection pads 15'.
In comparison with the above, the dimensions in the substrate width direction (the direction perpendicular to the substrate edge 1a) and the substrate longitudinal direction (the direction along the substrate edge 1a) are large, and the area is significantly increased. The connection pads 11 at both ends can be used for the terminal connection even when a stress caused by deformation, impact, or thermal expansion acts on the terminal connection portion by soldering during the assembling operation and use of the flat panel display device. This is to maintain high reliability.

[0007]

However, in the case of a driving printed wiring board having the above-described connection pad pattern, only the connection pads 11 'at both ends are extremely large in area, and the amount of solder placed on the connection pads is also small. Notably more. Therefore, there is a difficulty in the heat radiation of the solder at the connection pads 11 'at both ends, and it takes a long time for the solder to harden. Therefore, the work time required for soldering the input side terminal group 20 and the connection pad group 10 of each TCP becomes significantly longer than when large connection pads 11 'are not provided at both ends.

If the dimensions of the connection pads 11 'at both ends are reduced, the heat radiation for cooling and solidifying the solder is improved, but the strength of the mechanical connection is reduced, and deformation and impact are caused accordingly. If the connection reliability decreases.

On the other hand, if the soldering is performed on the entire surface of each of the connection pads 11 'at both ends, sufficient mechanical connection reliability can be obtained. However, it is confirmed that the soldering is performed on the entire surface of the pad. Was difficult or took considerable time to confirm.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and in a flat display device and a printed wiring board for driving used in the flat display device, a connection pad of the printed wiring board and a terminal group of a tape carrier package are used. Provided is a device capable of reducing the work time required for soldering. In addition, the present invention provides a device that can easily confirm whether or not soldering has been performed on the entire surface of large pads at both ends of a connection pad group.

[0011]

According to a first aspect of the present invention, there is provided a flat panel display device comprising a tape carrier package for inputting a drive to a peripheral connection portion of a display panel body, and an input terminal group of each tape carrier package and soldering. A print having a connection pad group to be connected, and having, at both ends of each of the connection pad groups, a fastening pad portion having a dimension in the substrate width direction and the substrate longitudinal direction larger than other connection pads in the connection pad group. In a flat panel display device including a wiring substrate, the fastening pad portion is separated into a plurality of connection pads.

According to the above configuration, the dissipation of heat from the solder placed on the fastening pad portion is promoted, so that the time required for cooling and solidifying the solder is reduced, and therefore the time required for soldering can be reduced. .

According to a second aspect of the present invention, there is provided a flat panel display device, wherein a tape carrier package for inputting drive to a peripheral connection portion of a display panel body, and a connection pad group connected by soldering to an input terminal group of each tape carrier package. And a printed wiring board having, at both end portions of each of the connection pad groups, fastening pad portions having dimensions in the board width direction and the board longitudinal direction larger than those of the other connection pads in the connection pad group. The display device is characterized in that the fastening pad has an overhang protruding from the area covered by the tape carrier package, and the solder protrudes out of the area on the overhang.

With such a configuration, it can be easily visually confirmed that sufficient soldering has been performed on the entire surface of the fastening pad.

5. The flat display device according to claim 4, wherein between the two adjacent connection pad groups, the overhanging portion overhangs from one fastening pad portion to the adjacent fastening pad portion. And the overhanging portions projecting from the adjacent fastening pad portion toward the one fastening pad portion are provided alternately.

With this configuration, it is possible to minimize an increase in the arrangement pitch of the connection pad group due to the provision of the overhang.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an exploded perspective view of a main part of a flat display device of an embodiment, in which solder is omitted, and FIG. 2 is an exploded perspective view of a main part particularly showing a state of soldering.

As in the case of the above-described prior art, a plurality of TCPs 2 are connected to the peripheral connection portion 31 of the display panel body 3 by the ACF.
(Anisotropic conductive film) and the like, and a driving IC 25 is mounted one at a time in a substantially central portion of each TCP 2.

Further, on the upper surface of the driving printed wiring board 1 extending along the peripheral connection portion 31, the input terminal group 20 on the lower surface of each TCP 2 and the connection pad group 10 for connection by soldering, respectively. Are provided along the edge 1 a on the peripheral connection portion 31 side of the driving printed wiring board 1.

Each of the connection pad groups 10 is arranged such that the signal pads 15 are arranged at a fixed small interval from the edge 1a on the side of the peripheral connection portion 31, and the rows of the signal pads 15 are sandwiched from both sides. It comprises a board inner side fastening pad 12 and a board end side fastening pad 13 arranged between each fastening pad 12 and the edge 1 a on the side of the peripheral connection portion 31.

The board inner fastening pad 12 and the board end side fastening pad 13 form a mechanical fastening portion 11 for maintaining the reliability of terminal connection against deformation and impact. The dimensions in the width direction (the direction perpendicular to the substrate edge 1a) and in the longitudinal direction of the substrate are large, and are formed in a remarkably large area. The board inner fastening pad 12 and the board end side fastening pad 13 are arranged close to each other via a slit-shaped separation portion 14.

In the illustrated example, the signal pads 15 are strip-shaped extending in the width direction of the substrate and have the same size as each other.
It has a substantially square shape that is larger than the long side dimension. The board end side fastening pad 13 has substantially the same dimension in the board width direction as the board inner fastening pad 12, and has a slightly larger dimension in the board longitudinal direction than the board inner fastening pad 12. The board end side fastening pad 13 projects beyond the board inside fastening pad 12 outside the connection pad group 10, that is, away from the signal pad 15.
The dimension in the longitudinal direction of the board is larger than the fastening pad 12 inside the board.

As shown in FIG. 2, the connection pad group 10 and T
When the input side terminal group 20 of the CP 2 is connected by the solder 4, a part or all of the overhang portion 13 a
It protrudes outward from the edge 2a in the substrate longitudinal direction in CP2. Therefore, when the solder is connected, the solder 4 protrudes from the edge 2 a of the TCP 2, and the edge 4 a of the TCP 2
To form a fillet (semi-flesh) 41 raised to the surface.

A specific example of the dimensional configuration of the connection pad group 10 is as follows. The width and arrangement interval of the signal pads 15 are 0.4 mm, and one side of the fastening pad 12 on the inside of the substrate is 0.9 mm. Further, the overhang width of the overhang portion 13a of the board end side fastening pad 13 is 0.7 mm, and therefore, the size of the board end side fastening pad 13 in the board longitudinal direction is (0.9 + 0.7) mm.
= 1.6 mm.

According to the above embodiment, the fastening pads are formed separately from the two fastening pads 12 and 13, and the heat is dissipated from the space 14 between them, so that the solder is cooled and solidified. The time required is reduced. Therefore, the time required for the soldering operation can be significantly reduced. Moreover, even if the fastening pads are formed separately, the total area of the pad surface of the fastening pad portion 11 can be reduced without increasing the size and area for arranging the fastening pads.
And the mechanical connection strength can be kept the same as in the case of the above-mentioned prior art.

Also, by providing the overhanging portion 13a, after soldering, the fastening pads 12, 13 can be checked simply by visually checking whether or not the appropriate fillet 41 of the solder 4 exists at the end 2a of the TCP 2. It can be easily determined whether or not the soldering has been sufficiently performed on the entire surface. This is because an appropriate fillet 41 is formed only when the solder placed on the board end side fastening pad 13 sufficiently heat-flows and is appropriately pressed from the connection terminal 21 of the TCP 2.

Further, by forming such a fillet 41, some improvement in connection strength can be expected.

In the above embodiment, the connection pad group 10
Of the two fastening pads 12, 1
3, but may be formed by three or four fastening pads. If the total area is substantially the same, substantially the same connection strength can be obtained, and the dissipation of heat from the separation portion 14 is promoted by an amount corresponding to the separation. In addition,
Here, the separation of the fastening pads is not limited to complete separation but may be partially continuous due to the constricted portion, as long as heat is sufficiently dissipated.

Although the overhang portion 13a is provided on the board-side fastening pad 13, the board-side fastening pad 12 may be provided. Alternatively, the board-side fastening pad 12 may be provided on both the fastening pads 12, 13. .

On the other hand, in the illustrated example, one fastening terminal 21 is provided at each end of the terminal group 20 of the TCP 2. However, two fastening terminals are provided at both ends of the terminal group 20 of the TCP2, and the fastening pads 12 and 13 are respectively provided.
May be connected.

In the above description, it is assumed that the connection pads at both ends in the connection pad group 10 are fastening pads for mechanical connection, and pads other than the fastening pads are signal pads. However, the connection pads at both ends also serve purposes such as ground connection and signal input in many cases. Further, connection pads other than the both end portions are used for purposes other than signal input and the like as necessary. Note that the connection pads at both ends may be dummy pads that are not used for electrical connection.

Next, a second embodiment will be described with reference to FIG.

In the driving printed circuit board 1 according to the second embodiment, the connection pad groups 10-n-1, 10-n, 10-n + 1,
.. Are provided on the substrate end side fastening pad 13 at the end on one side (left side in the figure) as in the above embodiment, and the connection pad groups 10-n-1 and 10-n are provided. ,
At the end of the other side (the right side in the figure) of 10-n + 1,...

Therefore, the overhanging portion of the left-side fastening pad portion 11 of one connection pad group 10-n and the overhanging portion of the right-side fastening pad portion 11 of the left adjacent connection pad group 10-n-1 are alternately arranged. Become. The same applies to the connection between the rightmost fastening pad portion 11 of one connection pad group 10-n and the leftmost fastening pad portion 11 of the connection pad group 10-n + 1 on the right.

For this reason, the connection pad groups 10-n-1, 10-
Even when there is no dimensional margin between n, 10-n + 1,..., connection pad groups 10-n-1, 10-n, 10-n by providing overhanging portions 12a, 13a. +1... Is increased only by the length e of the overhanging portions 12a and 13a in the substrate longitudinal direction.

As described above, according to the second embodiment, although the configuration of the fastening pad portion 11 is asymmetrical on the left and right, the interval between the connection pad groups 10 can be made smaller, which is advantageous.

In the second embodiment, the arrangement of the pads in each connection pad group 10 is the same. For example, for one connection pad group 10-n, the projecting portion For the adjacent connection pad groups 10-n-1 and 10-n + 1, an overhanging portion can be provided on the fastening pad 12 inside the substrate. Even with such a configuration, the overhanging portions are alternated between the adjacent connection pad groups 10, so that the same effect as in the second embodiment can be obtained.

The projecting portions 12a, 13a may have a shape projecting from the fastening pads 12, 13 in a peninsula shape.
That is, the size of the overhang portions 12a and 13a on the substrate width side may be smaller than the size of the fastening pads 12 and 13 on the substrate width side.

[0039]

As described above, the time required for cooling and solidifying the solder can be reduced, and therefore the time required for soldering can be reduced. Alternatively, it can be easily visually confirmed that sufficient soldering has been performed on the entire surface of the fastening pad.

[Brief description of the drawings]

FIG. 1 is a schematic exploded perspective view of a principal part showing a flat panel display according to a first embodiment of the present invention.

FIG. 2 is a schematic exploded perspective view of a principal part showing a state where the flat display device of the first embodiment is soldered and assembled.

FIG. 3 is an exploded perspective view schematically showing a main part of a flat panel display according to a second embodiment.

FIG. 4 is an exploded perspective view schematically showing a main part of a flat panel display according to a conventional technique.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Driving printed wiring board 10 Connection pad group 12, 13 Connection pad (fastening pad) at both ends of connection pad group 15 Connection pad (signal pad) other than both ends of connection pad group 2 TCP (tape carrier package) 20 TCP Input terminal group 3 Display panel body 4 Solder 41 Solder fillet

Claims (15)

[Claims] 1. A tape carrier package for inputting drive to a peripheral connection portion of a display panel main body, and a connection pad group connected by soldering to an input terminal group of each tape carrier package. A flat display device comprising, at both ends of a pad group, a printed wiring board having fastening pad portions having dimensions in the board width direction and the board longitudinal direction larger than those of other connection pads in the connection pad group, A flat display device, wherein a pad portion is separated into a plurality of connection pads. 2. A tape carrier package for performing a drive input to a peripheral connection portion of a display panel main body, and a connection pad group connected by soldering to an input terminal group of each tape carrier package. A flat display device comprising, at both ends of a pad group, a printed wiring board having fastening pad portions having dimensions in the board width direction and the board longitudinal direction larger than those of other connection pads in the connection pad group, A flat display device, wherein a pad portion has an overhanging portion protruding out of a region covered by the tape carrier package, and the solder protrudes out of the region on the overhanging portion. 3. The device according to claim 1, wherein the fastening pad has an overhang protruding outside the area covered by the tape carrier package, and the solder protrudes out of the area over the overhang. Item 2. The flat panel display according to item 1. 4. An overhanging portion between two adjacent connection pad groups extending from one fastening pad portion toward the adjacent fastening pad portion; 4. The flat display device according to claim 2, wherein the projecting portions projecting from the pad portion toward the one fastening pad portion are provided alternately. 5. 5. The flat display device according to claim 1, wherein the fastening pad portion is separated into a fastening pad on an end of the substrate and a fastening pad on the inner side of the substrate. 6. The flat display device according to claim 5, wherein the overhanging portions are provided on fastening pads on the end of the substrate at both ends of the connection pad group. 7. A connection pad group connected to an external terminal group by soldering, wherein both ends of each of the connection pad groups are in the substrate width direction and in the substrate width direction with respect to other connection pads in the connection pad group. A printed wiring board having a fastening pad having a large longitudinal dimension, wherein the fastening pad is separated into a plurality of connection pads. 8. A connection pad group connected to an external terminal group by soldering, wherein both ends of each of the connection pad groups are in the substrate width direction and in the substrate width direction more than other connection pads in the connection pad group. What is claimed is: 1. A printed wiring board having a fastening pad portion having a large dimension in a longitudinal direction, wherein the fastening pad portion has an overhanging portion protruding outside a region covered with the external terminal group. 9. A tape carrier package for inputting a drive to a peripheral connection portion of a display panel main body, and a connection pad group connected by soldering to an input terminal group of each tape carrier package. A flat display device comprising, at both ends of a pad group, a printed wiring board having a fastening pad portion having a dimension in a board width direction or a board longitudinal direction larger than other connection pads in the connection pad group, A flat display device, wherein a pad portion is divided into a plurality of connection pads along a dividing line in the longitudinal direction of the substrate. 10. A tape carrier package for inputting drive to a peripheral connection portion of a display panel main body, and a connection pad group connected by soldering to an input terminal group of each tape carrier package. A flat display device comprising, at both ends of a pad group, a printed wiring board having a fastening pad portion having a dimension in a board width direction and a board longitudinal direction larger than other connection pads in the connection pad group, The pad section is separated into a plurality of connection pads,
At least one of the separated connection pads has an overhang protruding out of the area covered by the tape carrier package, and the solder protrudes out of the area on the overhang. Flat display device. 11. A tape carrier package for performing drive input to a peripheral connection portion of a display panel main body, and a connection pad group connected by soldering to an input terminal group of each tape carrier package. A flat display device comprising, at both ends of a pad group, a printed wiring board having fastening pad portions having dimensions in the board width direction and the board longitudinal direction larger than those of other connection pads in the connection pad group, A flat display device, wherein the pad portion has a constricted portion. 12. The tape carrier package according to claim 1, wherein terminals at both ends of the input terminal group of the tape carrier package to be fastened to the fastening pad are divided corresponding to the fastening pad. The flat panel display according to claim 1. 13. A pad according to claim 1, wherein said fastening pad comprises at least one of a ground connection pad, a signal input pad and a dummy pad.
11. The flat panel display according to items 10 and 10. 14. In each of the connection pad groups, the fastening pad portion at one end is provided with the overhang portion at the end of the board, and the fastening pad portion at the other end is provided with the overhang inside the board. The flat display device according to claim 4, wherein an overhang portion is provided. 15. The overhanging portion is provided at an end of the substrate at the fastening pad portions at both ends in one of the connection pad groups, and the fastening pad portions at both ends in the connection pad group adjacent to the overhang portion are provided. The flat display device according to claim 4, wherein the overhang portion is provided inside the substrate.