JP2003017818A - Flexible circuit board and display unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flexible circuit board that is reduced in size and cost, and enhanced in wiring density. SOLUTION: This flexible circuit board has a prescribed wiring pattern formed on a film 37, a resist-removed section for mounting a drive IC 5 in a resist 12 coating the wiring pattern, and IC connecting terminals 6 in the resist-removed section. The circuit board also has terminals 3 for outside connection on the outside of the resist 12, alignment marks 7 for mounting the drive IC 5 at spots, from which the resist 12 is partially removed, and leads 11 which connect the terminals 6 and 3 to each other between the film 37 and the resist 12. The lead-out wiring 10 of the alignment marks 7 is arranged in parallel with the terminals 3 and alignment marks 4 for mounting displaying element are formed on the wiring 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible circuit board, and more particularly to an improvement in alignment marks for a flexible circuit board for mounting a display element.

The present invention also relates to a display device such as a liquid crystal or an El element using such a flexible circuit board.

[0003]

2. Description of the Related Art A conventional structure in which a flexible circuit board on which an IC is mounted is mounted on a liquid crystal display device will be described.

First, the manufacturing process of the flexible circuit board will be described with reference to FIGS.

FIG. 3 is a plan view of a conventional flexible circuit board obtained through the following steps, and FIG. 4 is a plan view of a liquid crystal display device in which the flexible circuit board 1 is mounted on a display element. .

20 to 30 μm is obtained by applying a polyimide varnish on a copper foil having a thickness of 4 to 12 μm and curing it.
By forming a thick polyimide film 37 and then etching a copper foil into a desired wiring pattern, an external connection terminal 3 for connecting to the display element 2 and an IC for connecting to the drive IC 5 which is the element chip. It is exposed as a display element mounting alignment mark 4 formed on both outer sides of the connection terminal 6 and the external connection terminal 3.

When the wiring pattern is formed by the etching as described above, at the same time, the driving IC mounting alignment mark 7, the driving IC mounting alignment mark pull-out wiring 10 drawn from the driving IC mounting alignment mark 7, the display element mounting The display element mounting alignment mark lead-out wiring 13 drawn out from the alignment mark 4 and the electrolytic plating pattern 9 are also provided in the region to be finally cut off during the contour cutting.

Therefore, the display element mounting alignment mark 4 is connected to the electroplating pattern 9 by the display element mounting alignment mark drawing wiring 13, and the drive IC mounting alignment mark 7 is also connected to the drive IC mounting alignment mark drawing wiring 10. Is connected to the electrolytic plating pattern 9.

Further, since the drive IC mounting alignment mark 7 exists in the lead 11 connecting the external connection terminal 3 and the IC connecting terminal 6, the drive IC mounting alignment mark lead-out wiring 10 contacts the lead 11. In order not to do so, the external connection terminals 3 are pulled out and connected to the electrolytic plating pattern 9.

Next, Au electroplating is performed on all the leads, the alignment marks, and the wiring. After that, a resist 12 is coated on the obtained wiring pattern, and a resist removing portion for mounting the driving IC 5 is provided in the resist 12 to expose the IC connection terminal 6, while the display element 2 is provided.
The external connection terminal 3 is also exposed by providing the resist removal portion also in the region to be connected to.

When removing the resist 12 as described above, at the same time, the alignment mark 4 for mounting the display element,
The drive IC mounting alignment mark 7, a part of the display element mounting alignment mark lead wiring 10 near the external connection terminal 3, and the drive element mounting alignment mark lead wiring 13 are also exposed.

After removing the resist, the flexible printed circuit board 1 is obtained by cutting the film sheet along a predetermined cut line 8.

Flexible circuit board 1 thus obtained
Recognizes the drive IC mounting alignment mark 7 on the flexible circuit board 1 by image processing or the like,
The drive IC 5 is connected by performing alignment with the drive IC 5.

Further, as shown in FIG. 3, the drive IC 5
Recognizing the display element mounting alignment mark 4 on the flexible circuit board 1 to which is connected by image processing or the like,
The display device is completed by performing alignment with the display element 2 and mounting the flexible circuit board 1 on the display element 2.

By providing the display element mounting alignment mark 4 as in the above structure, the flexible circuit board and the display element 2 can be aligned with high accuracy.

[0016]

However, in the flexible circuit board 1 having the above structure, the display element mounting alignment marks 4 are formed on both outer sides of the external connection terminals 3, and accordingly, the display element mounting is performed. The alignment mark lead-out wiring 13 for use also has to be formed on both outsides thereof, which increases the outer size of the flexible circuit board 1 in order to secure the space, resulting in the recent miniaturization and high density. We were unable to meet the market needs for wiring and cost reduction.

Therefore, the present invention has been completed in view of the above, and an object thereof is to provide a flexible circuit board which achieves downsizing, high-density wiring, and cost reduction.

Another object of the present invention is to provide a display device which can be aligned with a display element with high mounting accuracy by using the flexible circuit board of the present invention.

[0019]

In the flexible circuit board of the present invention, a predetermined wiring pattern is formed on the surface of a film, a protective film is coated on the wiring pattern, and a protective film for mounting an element chip is provided in the protective film. A protective film removing portion is provided, an element chip connecting terminal is formed in the protective film removing portion, and an external connecting terminal is formed in an outer region of the protective film, and these element chip connecting terminal and external connecting terminal are provided with leads. An element chip mounting alignment mark is formed on the part where the connection is made and a part of the protective film is removed, and an element chip mounting alignment mark lead wire arranged in parallel with the lead is extended near the external connection terminal. A flexible circuit board comprising: an external connection terminal and / or an alignment mark for mounting an element chip; It is characterized in that form.

Further, in the display device of the present invention, the external connection terminal of the flexible circuit board according to claim 1 on which an element chip is mounted, and the lead group of the display element made of liquid crystal or EL are formed by the display element mounting alignment mark. It is characterized in that the external connection terminal and the lead group are connected to each other while being aligned.

[0021]

In the flexible circuit board of the present invention, the display element mounting alignment mark and the display element mounting alignment mark lead-out wiring are not required on both outsides of the external connection terminals used in the conventional flexible circuit board as in the above configuration. As a result, high-density wiring can be performed, and as a result, the number of wirings taken from the mother film is increased, so that the manufacturing cost is reduced and a low-cost flexible circuit board can be provided.

Further, in the display device of the present invention, when the flexible circuit board of the present invention on which the element chip is mounted is arranged on the display element, the wiring pattern of the display element and the external connection of the flexible circuit board are used. By connecting the output signal of the element chip to the display element by connecting to the terminal, a display device having a small size, high density wiring and low cost is provided.

[0023]

DETAILED DESCRIPTION OF THE INVENTION The flexible circuit board of the present invention will be described in detail below with reference to FIGS.

FIG. 1 is a plan view of a flexible circuit board of the present invention, and FIG. 2 is a plan view before being cut out as a flexible circuit board. The same parts as those of the conventional flexible circuit board are designated by the same reference numerals. (Flexible Circuit Board of the Present Invention) As shown in FIG. 2, the flexible circuit board 1 is coated with polyimide varnish on a copper foil having a thickness of 4 to 12 μm and cured to give 20
A polyimide film 37 having a thickness of 30 μm is formed, a copper foil is etched into a predetermined wiring pattern, and the wiring pattern is electrolytically plated with Au. The resist serving as the protective film is formed on the plated wiring pattern. 12 is applied, and then the resist 12 is partially removed so that a part of the wiring pattern is exposed.

The wiring patterns exposed through such steps include (1) IC connection terminals 6 (2) external connection terminals 3 (3) drive IC mounting alignment marks 7 (4) drive IC mounting A part of the alignment mark lead-out wiring 10 (5) There is an electrolytic plating pattern 9.

At the terminal 6 of (1) above, the driving IC
5 is implemented. The terminal 3 of (2) is a terminal extended from the terminal 6 through the lead 11. The alignment mark 7, which is (3), is formed between the wirings of the leads 11. The lead wiring 10 as (4) is
The line extends from the alignment mark 7 to the vicinity of the terminal 3 so as not to come into contact with the lead 11, and is exposed at the same time as the terminal 3 in the vicinity of the terminal 3. Also, (1) to (4)
Connects to pattern 9, which is (5).

The flexible circuit board 1 of the present invention
In the above, the display element mounting alignment mark 4 is provided on the external connection terminal 3 and / or the drive IC mounting alignment mark lead-out wiring 10 which is a part of the wiring pattern.

After such a partial resist removing step,
The flexible circuit board shown in FIG. 1 was obtained by cutting the film 37 along a predetermined cut line 8.

In mounting the drive IC 5 on the flexible circuit board 1 having the above-described structure, the drive IC mounting alignment mark 7 is recognized by image processing or the like, and the drive IC 5 is aligned with the drive IC 5 by recognizing the alignment mark.
It was possible to connect 5 accurately.

Anisotropic conductive film (ACF) is used for connection.
Or non-conductive paste (NCP) etc.
It is fixed by heating it at a temperature of 220 ° C.

Subsequently, the alignment mark 4 for mounting the display element on the flexible circuit board 1 to which the driving IC 5 is connected is recognized by image processing or the like, and the alignment mark 4 is aligned with the display element 2 to display the display element 2 on the flexible circuit board 1. The display device was completed by implementing.

Thus, the flexible circuit board 1 of the present invention
According to this, the display element mounting alignment mark 4 is formed in the external connection terminal 3 on the drive IC mounting alignment mark lead-out wiring 10 in the outer region of the resist 12, so that an external device used in a conventional flexible circuit board can be obtained. The display element mounting alignment mark 4 and the display element mounting alignment mark lead-out wiring 13 provided on both outer sides of the connection terminal 3 are no longer required, the design efficiency is improved, and the size can be reduced and high-density wiring can be performed. . Moreover, the achievement of such high-density wiring has increased the number of pieces taken from the mother film, thereby reducing the manufacturing cost.

Next, another example of the present invention will be described.

FIG. 5 is a plan view of another flexible circuit board. The same parts as those of the flexible circuit board shown in FIG. 1 are designated by the same reference numerals.

In the flexible circuit board 1 described above, the display element mounting alignment mark 4 is formed on the drive element mounting alignment mark lead-out wiring 10 in the external connection terminal 3, but instead of this, in the present example. Is a display element mounting alignment mark 4 formed on both outer ends of the external connection terminal 3. Even in such a configuration, the above-mentioned advantageous effects are obtained.

The present invention is not limited to the above-mentioned embodiment, and various modifications and improvements may be made without departing from the scope of the present invention. For example, although a copper foil is used in this example, instead of this, copper may be vapor-deposited on a polyimide film to form a film substrate.

In the above manufacturing process, a wiring pattern was formed, and then the wiring, the alignment mark, and the lead were electrolytically plated with Au to form the resist 12. Instead of this, an IC in which a wiring pattern is formed and the resist 12 is covered first and the resist 12 is not covered
The connection terminal 6, the external connection terminal 3, the display element mounting alignment mark 4 and the drive IC mounting alignment mark 7 may be electrolytically plated with Au.

Instead of the resist, another protective film such as a polyimide film may be formed.

The removing process is not limited to one, and for example, a mask is formed on the resist removing portion,
The wiring may be exposed by removing this after applying the resist. Alternatively, the wiring may be exposed by exposing the mask and etching.

Various element chips having a driving IC function, such as a memory and a controller, may be used as the element chips.

By connecting the lead wiring extending from one drive IC mounting alignment mark 7 to the lead 11, the lead 11 may also serve as the drive IC mounting alignment mark lead wiring.

Since the alignment mark is recognized by image processing or the like, various shapes and structures such as an X mark can be adopted as long as it is within the recognized range.

Further, the display element mounting alignment mark may be formed on both the external connection terminal 3 and the drive IC mounting alignment mark lead-out wiring 10.

Furthermore, the number of display element mounting alignment marks is two in this example, but is not limited to this.

For example, by further forming one, two, or three or more spare alignment marks,
Even if the original alignment mark is unclearly formed by the etching process in the previous step, it can serve as a substitute mark. and so on.

(Display Device of the Present Invention) In the present invention,
It is most effective in further miniaturizing the already miniaturized display device, and the display element mounting alignment mark 4 and the display provided on both outer sides of the external connection terminals 3 used in the conventional flexible circuit board 1 are provided. The effect is remarkable because the element mounting alignment mark lead-out wiring 13 is no longer necessary.

The display device of the present invention will be described below with reference to FIGS. 6 to 9 using a liquid crystal display device as an example. The same members as those of the display device shown in FIG. 3 are designated by the same reference numerals.

FIG. 6 is a plan view of a simple matrix type liquid crystal display device according to the present invention, and FIG. 7 is a plan view as a display element before the flexible circuit board of the present invention is mounted on the liquid crystal display device. Is. 8 and 9 are plan views showing the wiring pattern of the display element.

First, the outline of this liquid crystal display device will be described with reference to FIG. 6, which has a structure in which one flexible circuit board 1 is provided for one display element 2 and has a large area glass substrate 14 and a small area. The display screen 35 is provided by disposing the glass substrate 15 and the liquid crystal material therebetween.

A wiring pattern extending from the display screen 35 is formed on the non-display screen on the large area glass substrate 14.

As shown in FIG. 7, this wiring pattern has a structure in which the large-area glass substrate 14 is gathered and arranged near one side, and a plurality of scanning leads 16 are arranged near both outsides. And multiple signal leads 1 near the center
A signal lead group 19 in which 7 are arranged is formed and connected to the flexible circuit board 1. The normal space 2 is provided between the scanning lead group 18 and the signal lead group 19.
0 is provided.

The wiring structure of the scanning leads 16 and the signal leads 17 will be described with reference to FIGS. 8 and 9. First, the wiring configuration of the scanning lead 16 will be described with reference to FIG.

The scanning leads 16 are arranged on the large-area glass substrate 36 so as to be orthogonal to the signal leads 17, and the upper half of the scanning leads 16 on the display screen is in one direction and the lower half is in the other direction. The scan lead group 18 extends on the screen and is laid out near the connection with the external connection terminal 3 on the flexible circuit board.

In the wiring structure of the signal lead 17 shown in FIG. 9, the signal lead 17 is arranged on the glass substrate 15 of the small area so as to be orthogonal to the scanning lead 16, and the signal lead 17 on the display screen is externally connected. The signal lead group 19 is laid out near the connection with the connection terminal 3.

The scanning lead group 18 and the signal lead group 19 thus formed at the connecting portion are connected to the external connection terminals 3 on the flexible circuit board, and thereby the drive mounted on the film 37 of the same board. An output voltage is applied to the display element 2 from the IC 5 to provide a structure for displaying.

Thus, in the display device having the above structure,
This is a structure in which one flexible circuit board is arranged for one display element, and one drive IC 5 is mounted on this circuit board. According to this structure, both ICs for scanning and signal are provided by this IC. An output voltage is applied to the device to display an image.

According to such a display device, the following operational effects are also obtained.

As shown in FIG. 7, two scanning lead groups 18
In the wiring pattern having the structure in which the signal lead group 19 is interposed between the lead groups 18 and 19, a space 20 is provided between the lead groups 18 and 19. This space 20 is used for the scanning lead when performing the full lighting inspection. This is to prevent the 16 and the signal lead 17 from being short-circuited.

The all-lighting inspection is performed by using a zebra rubber, that is, a rubber in which electricity flows in a vertical direction in which conductive layers and insulating layers are alternated and which is insulated in a horizontal direction and which conducts only in one direction. A signal is applied to check for breaks in each lead.

The space 20 as described above has not been conventionally used for purposes other than such inspection, but the space can be effectively used by using the flexible circuit board 1 of the present invention. That is, when mounting the flexible circuit board 1 on the display element 2, as shown in FIGS.
As shown in FIG. 4, the display device mounting alignment mark 4 on the flexible circuit board 1 may be provided between the scanning lead group 18 and the signal lead group 19 (in the case of this configuration, the display shown in FIG. This corresponds to the element mounting alignment mark 4), whereby the display element mounting alignment mark 4 on the flexible circuit board 1 can be arranged in the space 20. Therefore, by using the flexible circuit board 1 shown in FIG. 1 as compared with the flexible circuit board shown in FIG. 4, further miniaturization of the liquid crystal display device can be achieved.

(Specific Configuration Example of Liquid Crystal Display Panel) The liquid crystal panel 20 used for the display screen 35 will be described with reference to FIG. The figure is a cross-sectional view of the liquid crystal display panel 36.

The liquid crystal display panel 36 may be a completely transmissive type, a reflective type, or a semi-transmissive type liquid crystal display device. By using a backlight,
Be transparent or semi-transparent.

In this example, a reflective liquid crystal display device which becomes a reflective type by not using a backlight will be described.

According to the STN type color liquid crystal display panel 36 shown in FIG. 10, the transparent substrate 24 made of glass or synthetic resin and the transparent substrate 34 are opposed to each other, but an acrylic resin material or the like is provided on the inner surface of the transparent substrate 34. Random convex array groups are formed by arranging a large number of substantially hemispherical convex portions 33 with a resin made of, and silver or silver alloy as a light reflecting material is coated on the convex array groups and reflected. The film 32 is formed, and the color filter 31 is provided on the reflective film 32.
Further, between the color filters 31, a thin film made of a metal such as aluminum or chromium or a black matrix which is a light-shielding film formed of a photosensitive resist may be formed.

Then, SiO is formed on the color filter 31.
_2. Overcoat layer 30 made of resin is coated, and a plurality of transparent electrodes 29 made of ITO arranged in parallel and an alignment film 28 made of polyimide resin rubbed in a certain direction are sequentially formed on the overcoat layer 30. ing.

On the other hand, on the inner surface of the transparent substrate 24, a plurality of transparent electrodes 25 made of ITO arranged in parallel are formed, and an alignment film 26 made of a polyimide resin rubbed in a certain direction is formed.
And are sequentially formed.

The transparent electrode 25 and the transparent electrode 29 are orthogonal to each other. In addition, S is formed between the transparent electrode 25 and the alignment film 26.
an insulating layer made of iO ₂ may be provided.

The color filter 31 is formed by photolithography by coating a substrate with a photosensitive resist prepared in advance by a pigment dispersion method, that is, a pigment (red, blue, green, etc.).

Various transparent substrates 24 thus formed,
34 is attached by a sealing material via the liquid crystal layer 27 made of chiral nematic liquid crystal twisted at an angle of 200 to 270 °, for example. Further, a large number of spacers (not shown) are arranged between the transparent substrates 24 and 34 to keep the thickness of the liquid crystal layer 27 constant.

On the display screen side of the liquid crystal display panel 36 having the above structure, a first retardation film 23, a second retardation film 22 made of polycarbonate, etc., and a polarizing plate 21 made of an iodine film are sequentially formed to form a reflection type liquid crystal display. It becomes a device.

In the reflection type liquid crystal display device having the above-mentioned structure, the irradiation light by the external irradiation such as sunlight and fluorescent light is generated by the polarizing plate 21, the second retardation film 22, the first retardation film 23 and the liquid crystal layer. Light that sequentially passes through the display screen 27 but is incident on the inside of the display screen passes through the color filter 31 and is reflected by the reflective film 32.
After passing through the first retardation film 23, the second retardation film 22 and the polarizing plate 21, light is emitted and stable and clear color display can be performed.

The transparent electrode 24 of the liquid crystal display panel 36 described above is a signal lead, and the transparent electrode 29 is a scanning lead.

The liquid crystal display device is not limited to the above embodiment, and various modifications and improvements can be made without departing from the scope of the present invention. For example, in the above embodiment, a reflective STN simple simple matrix type color liquid crystal display device has been described, but a transmissive type and a semi-transmissive type may be used. Similar effects can be obtained even in a monochrome liquid crystal display device, a monochrome type STN type simple matrix liquid crystal display device, or a TN type simple matrix type liquid crystal display device.

[0074]

As described above, according to the flexible circuit board of the present invention, a predetermined wiring pattern is formed on the surface of the film, a protective film is coated on the wiring pattern, and an element chip is mounted in the protective film. And a terminal for external connection is formed in the outer region of the protective film, and at least these IC connecting terminal, external connecting terminal and both of them are connected. An element is formed by the lead connecting the terminals to form the wiring pattern, and an alignment mark for mounting an element chip is formed on a part of the protective film, and the element is aligned with the lead and is pulled out from the alignment mark for mounting the element chip. Alignment mark lead-out wiring for chip mounting is provided, and terminals for external connection and / or alignment mark lead-out wiring for element chip mounting By forming the alignment mark for mounting the display element on the display element, the alignment mark for mounting the display element used in the conventional flexible circuit board and the wiring for pulling out the alignment mark for mounting the display element drawn from the alignment mark are not required, and the design Efficiency was improved and high-density wiring was possible.

Further, in the present invention, since the high-density wiring is achieved, the number of wirings taken from the mother film is increased, which reduces the manufacturing cost, and as a result, achieves the miniaturization and cost reduction of the flexible circuit. The substrate could be provided.

Further, in the display device of the present invention, the flexible circuit board of the present invention on which the element chip is mounted is arranged on the display element, and the wiring pattern of the display element and the external connection terminal of the flexible circuit board. By connecting the output signal of the element chip to the display element by connecting to the display element, a display device having a small size, high density wiring, and low cost is provided.

[Brief description of drawings]

FIG. 1 is a plan view of a flexible circuit board of the present invention.

FIG. 2 is a plan view of the flexible circuit board of the present invention before film cutting.

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

FIG. 4 is a plan view of a conventional liquid crystal display device.

FIG. 5 is a plan view of another flexible circuit board of the present invention.

FIG. 6 is a plan view of a display device on which the flexible circuit board of the present invention is mounted.

FIG. 7 is a plan view of a display device on which the flexible circuit board of the present invention is mounted.

FIG. 8 is a plan view in which scanning leads are wired on a display screen.

FIG. 9 is a plan view in which signal leads are wired on a display screen.

FIG. 10 is a cross-sectional view of a liquid crystal display panel.

[Explanation of symbols]

1 ... Flexible circuit board 2 ... Display element 3 ... External connection terminal 4 ... Alignment mark for mounting display element 5 ... Drive IC 6 ... IC connection terminal 7 ... Alignment mark for driving IC 8 ... Outer shape 9 ... Electroplating pattern 10 ... Wiring for pulling out alignment mark for driving IC 11 ... Lead 12 ... Resist 13 ... Alignment mark lead-out wiring for mounting display element 14 ... Large area glass substrate 15 ... Small area glass substrate 16 ... Scan lead 17 ... Signal lead 18 ... Scanning lead group 19 ... Signal lead group 20 ... space 21 ... Polarizing plate 22 ... Second retardation film 23 ... First retardation film 24 ... Upper glass substrate 25 ... Transparent electrode 26 ... Alignment film 27 ... Liquid crystal layer 28 ... Alignment film 29 ... Transparent electrode 30 ... Overcoat layer 31 ... Color filter 32 ... Reflective film 33 ... Hemispherical convex portion 34 ... Lower glass substrate 35 ... Display screen 36 ... Liquid crystal display panel 37 ... Film

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01L 23/12 H01L 23/12 FF term (reference) 2H092 GA32 GA38 GA40 GA43 GA45 GA46 GA48 GA50 GA51 GA59 HA11 HA12 HA18 HA24 HA25 HA28 MA02 MA10 MA11 MA12 MA14 MA17 MA43 NA17 NA25 NA27 NA29 PA06 5E338 AA12 AA16 BB65 BB75 CC01 CD32 DD12 DD32 EE41 EE43 5F044 KK03 KK21 5G435 AA18 BB12 EE40 EE47 KK03 KK09

Claims (2)

[Claims] 1. A predetermined wiring pattern is formed on the surface of a film, a protective film is coated on the wiring pattern, and a protective film removing portion for mounting an element chip is provided in the protective film. Element chip connection terminals, external connection terminals are formed in the outer region of the protective film, these element chip connection terminals and external connection terminals are connected by leads, and a part of the protective film is removed. A flexible circuit board, in which an alignment mark for mounting an element chip is formed in a portion where the lead is provided, and an alignment mark lead-out wiring for mounting the element chip arranged in parallel with the lead extends near the external connection terminal. A flexible circuit board having a display element mounting alignment mark formed on a terminal and / or an element chip mounting alignment mark lead-out wiring. 2. The external connection terminal of the flexible circuit board according to claim 1 on which an element chip is mounted and the lead group of the display element made of liquid crystal or EL are aligned with the display element mounting alignment mark, and A display element characterized in that these external connection terminals are connected to a lead group.