JPH11258621A - Flexible wiring board, liquid crystal display device, and electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the flexible wiring board which can be bent and made more small-sized, and the liquid crystal display device and electronic equipment using it. SOLUTION: The flexible wiring board 10 has a flexible base film 12 provided with slit parts 15 and 16 and a wire 14 which is formed on the base film 12 across the slit parts 15 and 16. The wire 14 has a lead-around part 14c, led around obliquely across the long axes of the slit parts 15 and 16, on the slit parts 15 and 16 and is covered with an insulating thin film 18 at least on the slit parts 15 and 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a flexible wiring board, a liquid crystal display using the same, and an electronic apparatus.

[0002]

2. Description of the Related Art In order to increase the degree of freedom in circuit layout and achieve higher density and integration of liquid crystal display devices, flexible wiring in which wiring or an IC (Integrated Circuit) chip is mounted on a film-shaped substrate has conventionally been used. A board is bent at a wiring portion.

[0003] In such a flexible wiring board, a slit portion is usually formed on a film-shaped substrate at a bent portion to facilitate bending. The wires are formed so as to cross the slit at right angles to the longitudinal axis of the slit in order to prevent the wires crossing the slit from contacting each other at the time of bending and causing a conduction failure.

[0004]

By the way, in recent years, there has been a tendency for electric and electronic equipment to be more strongly required to be smaller, thinner and lighter in addition to high performance and high function. Therefore, there is a demand for further miniaturization while maintaining and improving the performance of each component constituting the device.

However, in the above-mentioned prior art, since the longitudinal axis of the slit and the wiring must be orthogonal to each other, it is necessary to secure a slit forming area, and it is difficult to further reduce the size of the flexible wiring board which is easily bent.

[0006] The present invention has been made in view of the above problems, and an object of the present invention is to make it easy to bend, and
An object of the present invention is to provide a flexible wiring board that can be further miniaturized, a liquid crystal display device using the same, and an electronic apparatus.

[0007]

In order to solve the above-mentioned problems, the invention according to claim 1 is characterized in that a flexible base film provided with a slit portion is provided on the base film so as to cross the slit portion. A wiring formed on the slit portion, the wiring portion has a routing portion that is routed at an angle that obliquely intersects a longitudinal axis of the slit portion, and at least on the slit portion. It is characterized by being covered with an insulating thin film.

According to the first aspect of the present invention, it is possible to reduce the size of the flexible wiring board which can be easily bent.

That is, since the slit portion is formed in the base film, the flexible wiring board can be easily bent at this position. Then, the wiring traversing the slit portion has a routing portion on the slit portion which is routed at an angle crossing the longitudinal axis of the slit portion obliquely, and is covered with an insulating thin film on the slit portion. From, while preventing the occurrence of short circuit and poor conduction due to bending,
The wiring can be shorter than before. For this reason, it is possible to reduce the size of the flexible wiring board because the wiring can be shortened as compared with the related art.

Since the miniaturization is possible as described above,
It is possible to reduce the price by improving the efficiency in manufacturing the flexible wiring board and to save the space when the flexible wiring board is incorporated in another device.

In addition, on the slit portion, in addition to a routing portion obliquely intersecting with the longitudinal axis of the slit portion, a wiring portion that is orthogonal to or parallel to the longitudinal axis may be located.

Further, the insulating thin film may be formed so as to cover the slit portion, or may be formed on the wiring itself.

According to a second aspect of the present invention, there is provided a flexible base film having a bent portion, and a wiring formed on the base film across the bent portion,
The wiring has a routing portion on the bending portion that is routed at an angle that obliquely intersects the longitudinal axis of the bending portion, and the base film is formed to be thinner than the other at the bending portion. Features.

According to the second aspect of the present invention, it is possible to reduce the size of the flexible wiring board which can be easily bent.

That is, since a thinner bent portion is formed in the base film, bending of the flexible wiring board at this position becomes easier. Further, since the base film is not cut off, it is possible to prevent short-circuiting and poor conduction of wiring at the time of bending by the base film at the bent portion. Since the wiring crossing the bent portion is routed on the bent portion at an angle that obliquely intersects the longitudinal axis of the bent portion, the length of the wiring can be reduced as compared with the related art.
As described above, the wiring can be shortened as compared with the related art, so that the size of the flexible wiring board can be reduced.

Since the miniaturization is possible as described above, the cost can be reduced by improving the efficiency of manufacturing the flexible wiring board, and the space can be reduced when the flexible wiring board is incorporated into another device. It becomes possible.

In addition, on the bent portion, in addition to the routing portion obliquely intersecting with the longitudinal axis of the bent portion, a wiring portion that is orthogonal to or parallel to the longitudinal axis may be located.

According to a third aspect of the present invention, in the flexible wiring board according to the first or second aspect, an IC chip connected to the wiring is mounted on the base film. .

According to the third aspect of the present invention, since the IC chip connected to the wiring is mounted on the base film of the flexible wiring substrate which can be reduced in size, the flexibility of mounting the IC chip is improved. The size of the wiring board can be reduced.

The invention according to claim 4 has a liquid crystal display panel in which liquid crystal is sealed between two transparent substrates, and a flexible wiring board connected to the liquid crystal display panel. The flexible wiring board is the flexible wiring board according to any one of the first to third aspects.

According to the fourth aspect of the present invention, since the flexible wiring board connected to the liquid crystal display panel is a flexible wiring board that can be reduced in size, the flexible wiring in the liquid crystal display device is provided. The area occupied by the substrate can be reduced. For this reason, the liquid crystal display device can be downsized while maintaining the performance and functions, or by mounting more components while maintaining the size, to form a liquid crystal display device with higher performance and higher functionality. It is possible to do.

According to a fifth aspect of the present invention, there is provided a liquid crystal display device according to the fourth aspect.

According to the fifth aspect of the present invention, since a liquid crystal display device capable of miniaturization, high performance, and high functionality is used, an electronic device having a liquid crystal display device can be reduced in size and improved in performance.・ High functionality is possible.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram schematically showing an embodiment of a flexible wiring board according to the present invention, wherein FIG.
(B) is a sectional view taken along line bb in (a).

In FIG. 1, a flexible wiring board 10 has a large number of wirings 14 formed on one surface of a base film 12 and an IC chip 20 connected to the wirings 14.
And coated with a chip coat 22. Slits 15 and 16 are formed in the base film 12 so as to cross the wiring 14, and an insulating thin film 18 is formed in the slits 15 and 16. Further, on the surface of the flexible wiring board 10 where the wiring 14 is formed, the slit portion 1
The insulating coat 17 is formed avoiding the portions 5 and 16.

More specifically, the base film 12 is made of a polyimide resin and has flexibility. Then, rectangular slit portions 15 and 16 are formed in portions where flexibility is required more than others due to connection and arrangement with other components.
These slit portions 15 and 16 are formed parallel to each other.

The insulating thin film 18 is made of an insulating and flexible material such as a polyimide resin.
It is provided to protect and insulate the exposed wiring 14 at 5 and 16. In order to achieve such an object, the insulating thin film 18 is formed so as to be thinner than the base film 12 and to have such a thickness that the functions of the slit portions 15 and 16 are not lost, and to close the slit portions 15 and 16. The method for forming the insulating thin film 18 is not particularly limited, but in the present embodiment, it is formed by printing.

Incidentally, the insulating thin film 18 is
The formation position is not particularly limited as long as the wiring 14 can be reliably insulated at 16. For example, as shown in FIG. 1B, the wiring 14 may be formed on the back side of the wiring 14, may be formed on the front side of the wiring 14, or may be formed so as to sandwich the wiring 14 from both the front and back sides. Alternatively, the wiring 14 may be formed so as to coat the wiring 14 itself while leaving a gap between the adjacent wirings 14.

The wiring 14 is formed by plating a conductive foil on the base film 12. The plurality of wirings 14 are formed so as to connect the four sides of the IC chip 20 to the peripheral edges 12a and 12b of the base film 12.

At this time, the wiring 14 has an end 14a connected to the IC chip 20 and an end 14b arranged at a wider pitch than the end 14a and connected to the peripheral edges 12a and 12b.
And a routing portion 14c connecting the end portion 14a and the end portion 14b. Then, the wiring 14 traversing the slit portion 15 bends on the slit portion 15 and moves from the routing portion 14c to the end portion 14b. On the other hand, the wiring 14 traversing the slit portion 16 traverses the slit portion 16 at the routing portion 14c. Further, the routing unit 14c
Are formed so as to obliquely intersect the longitudinal axes of the slit portions 15 and 16. Therefore, each wiring 14 is bent at the boundary between the end 14b and the routing portion 14c.

The end 14 a of the wiring 14 is covered with an insulating coat 17. This insulating coat 17 is used for wiring 1
4 is provided in order to provide insulation and prevent dust, foreign matter, solder, and the like from adhering to the wiring 14. And
The insulating coat 17 is formed by applying an epoxy or UV paint over the wiring 14.

The IC chip 20 and the chip coat 22 have a known structure. Therefore, detailed description thereof is omitted here.

The flexible wiring board 10 having such a structure is
Using the film-like substrate 11 shown in FIG.
It is formed by a utomated bonding method. That is,
Punch hole 11a formed at the end of film substrate 11
The IC chip 20 is collectively bonded via bumps to the end portions 14a of the wirings 14 protruding into the through holes 11b while moving the film-shaped substrate 11 by using the method. Thereafter, the IC chip 20 is covered with the chip coat 22 and is punched into a predetermined shape to complete the flexible wiring substrate 10 shown in FIG.

The IC chip 20 is connected to the base film 1
As long as it can be securely mounted on the T.2, a method other than the TAB method such as a wire bonding method can be used.

The flexible wiring board 1 having such a configuration
0 is the base film 1 in the slit portions 15 and 16.
2 is partially removed, so that the slits 15, 1
6 is improved in flexibility. For this reason, bending and the like become easier than before.

The slit portions 15 and 16 are formed of the insulating thin film 1.
8 so that in the direction of the arrow shown in FIG.
When the flexible wiring board 10 is bent at the positions of the slits 15 and 16, the wirings 14 do not contact each other, and the occurrence of a short circuit or the like is prevented.

Further, the wiring 14 and the slit portions 15 and 16
It is not necessary to make the longitudinal axes perpendicular to each other, so that the size of the flexible wiring board 10 can be reduced. Therefore, it is possible to improve the efficiency of manufacturing the flexible wiring board 10 at the time of manufacturing, and it is possible to provide the flexible wiring board 10 at a low price. Further, since the space occupied in the electronic device can be reduced, it is possible to reduce the size of the electronic device as a whole, increase the degree of freedom in assembling positions with other components, or increase the number of components to achieve higher functionality.

Next, FIG. 3 is a perspective view showing an embodiment of an electronic apparatus according to the present invention. The electronic device shown in FIG.
2 and a display unit 48 including a liquid crystal display screen 46.

The liquid crystal display screen 46 is formed including the liquid crystal display device 30 shown in FIG. In addition, FIG.
1 is a perspective view illustrating an embodiment of a liquid crystal display device according to the present invention.

Referring to FIG. 1, a liquid crystal display device 30 includes a liquid crystal display panel 32 and a flexible wiring board 10 connected thereto.

The liquid crystal display panel 32 has a first substrate 32a and a second substrate 32 made of transparent glass or plastic.
As shown in FIG. 5, a liquid crystal 38 is sealed through a seal member 36 between the layers b. Band-shaped transparent electrodes 34 and 35 made of ITO or the like are provided on the surfaces of the first substrate 32a and the second substrate 32b facing each other.
Thus, at least a dot matrix type liquid crystal display panel 32 is formed. Further, as shown in FIG. 4, the first substrate 32a and the second substrate 32b are formed such that the first substrate 32a is larger than the second substrate 32.

The flexible wiring board 10 is the same as the flexible wiring board 10 shown in FIG. 1, and for example, as shown in FIG.
At the end 14b of the wiring 14 crossing the slit portion 16, the wiring 14 is connected to the transparent electrode 34 of the first substrate 32a. Then, as shown in FIG.
It is bent at the slit part 16 so that 0 faces each other. For this reason, the flexible wiring board 10 is incorporated in the personal computer 40 of FIG. 2 in a form hidden behind the liquid crystal display panel 32.

FIG. 5 is a sectional view taken along line VV in FIG.

Since the liquid crystal display device 30 has such a configuration, the functions of the personal computer 40 can be improved by incorporating more components into the display unit 48. That is, by reducing the size of the flexible wiring board 10, the space occupied by the folded flexible wiring board 10 on the back side of the liquid crystal display panel 32 can be reduced. For this reason, it becomes possible to incorporate other components into the empty space.

Further, the liquid crystal display device 30 has a slit 1
Since the flexible wiring board 10 having 5 and 16 is used, the flexible wiring board 10 can be easily folded into the back side of the liquid crystal display panel 32. And the slit part 1
Since the insulating layers 5 and 16 are covered with the insulating thin film 18, such an arrangement does not cause a short circuit of the wiring 14. Therefore, a highly reliable liquid crystal display device 30 can be obtained.

FIGS. 6A and 6B are views showing another example of the flexible wiring board according to the present invention, wherein FIG. 6A is a plan view and FIG.
FIG. 3 is a schematic view of a cross section taken along line b′-b ′ of FIG.

In the figure, a flexible wiring board 50 is
IC chip 6 on PC (Flexible Printed Circuit) 51
0 is mounted and formed.

The FPC 51 is formed by forming a large number of wirings 54 on the surface of a base film 52 made of polyimide, and further covering the wiring with an insulating film 58. The insulating film 58 is formed after the mounting of the IC chip 60.

Here, the base film 52 has an end 5
A bent portion 56 is formed in each of 2a and 52b. The bent portion 56 is formed by making the thickness of the base film 52 in the portion thinner than the other portions.

Further, at least a part of the wiring 54 has a routing portion 54c that is routed at an angle that obliquely intersects the longitudinal direction of the bent portion 56, and traverses the bent portion 56 at the routing portion 54c. It is arranged to be. Other configurations are the same as those of the wiring 14 described above.

The insulating film 58 is made of a polyimide resin and is formed in a region other than the bent portion 56.

Since the flexible wiring board 50 has such a configuration, it is possible to further reduce the size of the easily bent flexible wiring board. That is, since the thickness of the substrate at the bent portion 56 is smaller than that of the other portions, the bending at this portion becomes easy. Further, since the base film 52 remains in the bent portion 56, the wiring 54 is not exposed in the bent portion 56. Further, the wiring 54
Is covered with the insulating film 58, so that the wires 54 hardly come into contact with each other regardless of whether the bent portion 56 is folded on the back side or the front side of the flexible wiring board 50. Therefore, the wiring 54 can be formed at an angle that obliquely intersects the longitudinal direction of the bent portion 56. Since it is not necessary to form all the wirings 54 at an angle perpendicular to the longitudinal axis of the bent portion 56, it is possible to promote the miniaturization of the flexible wiring substrate 50 that can be easily bent.

FIG. 7 is a schematic sectional view showing another embodiment of the liquid crystal display device according to the present invention.

In the figure, the liquid crystal display panel 32 has the same configuration as the liquid crystal display panel 32 shown in FIG. On the other hand, the flexible wiring board 50 has the same configuration as the flexible wiring board 50 shown in FIG. Then, the flexible wiring board 50
Is mounted on the liquid crystal display panel 32 instead of the flexible wiring board 10 shown in FIG.

More specifically, in the flexible wiring board 50, the wiring 54 is connected to the transparent electrode 34 of the first substrate 32a of the liquid crystal display panel 32 at the end 52b. And
The IC chip 60 is bent at the bending portion 56 so as to be hidden behind the liquid crystal display panel 32.

The end 52a is bent at a bent portion 56 near the end 52a for connection to a connector (not shown).

With the liquid crystal display device 30 having such a configuration, it is possible to incorporate more components into the display section 48 of the personal computer 40 shown in FIG. As a result, it is possible to improve the functions and reduce the size of the personal computer 40.

Since the flexible wiring board 50 having the bent portion 56 is used, the flexible wiring board 50
Can be easily folded on the back side of the liquid crystal display panel 32. Further, since the base film 52 remains in the bent portion 56, such an arrangement does not cause a short circuit of the wiring 54 or the like. Therefore, a highly reliable liquid crystal display device 30 can be obtained.

The embodiment of the present invention is not limited to the above-described example, and can be variously changed within the scope of the present invention.

For example, the wiring routing portions of the flexible wiring board may all have the same pitch, or portions having the same pitch and portions having an increased pitch may be mixed. The slit portion and the bent portion may be formed in any portion of such a routing portion as long as the slit portion and the bent portion include a region where the longitudinal axis and the wiring obliquely intersect. Further, one or more slit portions or bent portions may be formed in an arbitrary number. Further, a thin bent portion is formed instead of the slit portions 15 and 16 shown in FIG.
A slit portion may be formed at the position of the bent portion shown in FIG.

Further, 2 forming one liquid crystal display panel
The transparent substrates may be made of glass or a flexible film, or may be used by combining transparent substrates of different materials one by one.

Furthermore, the liquid crystal display device according to the present invention
It may be configured to include an input device.

The electronic device according to the present invention may be a mobile phone, a pager, or the like, in addition to the personal computer described above.

[Brief description of the drawings]

FIGS. 1A and 1B are schematic diagrams showing an embodiment of a flexible wiring board according to the present invention, wherein FIG. 1A is a plan view and FIG. 1B is a cross-sectional view taken along the line bb in FIG.

FIG. 2 is a diagram showing an embodiment of a flexible wiring board according to the present invention.

FIG. 3 is a perspective view illustrating an example of an electronic apparatus according to the invention.

FIG. 4 is a perspective view showing an embodiment of a liquid crystal display device according to the present invention.

FIG. 5 is a schematic view of a cross section taken along line VV in FIG. 4;

6A and 6B are diagrams showing another embodiment of the flexible wiring board according to the present invention, wherein FIG. 6A is a plan view, and FIG. 6B is a schematic view of a cross section taken along line b′-b ′ in FIG. is there.

FIG. 7 is a schematic sectional view showing another embodiment of the liquid crystal display device according to the present invention.

[Explanation of symbols]

 10, 50 Flexible wiring board 12, 52 Base film 14, 54 Wiring 14c, 54c Routing part 15, 16 Slit part 18 Insulating thin film 20, 60 IC chip 30 Liquid crystal display device 56 Bending part 58 Insulating film

Claims (5)

[Claims] 1. A flexible base film provided with a slit portion, and a wiring formed on the base film across the slit portion, wherein the wiring is formed of the slit portion. A flexible wiring board, comprising: a wiring portion on the slit portion, the wiring portion being routed at an angle obliquely intersecting with the longitudinal axis, and covered with an insulating thin film at least on the slit portion. 2. A flexible base film having a bent portion, and a wiring formed on the base film across the bent portion, wherein the wiring is formed by a longitudinal axis of the bent portion. The flexible wiring board according to claim 1, further comprising, on the bent portion, a routing portion that is routed at an obliquely intersecting angle, and wherein the base film is formed to be thinner than the other at the bent portion. 3. The flexible wiring board according to claim 1, wherein an IC chip connected to the wiring is mounted on the base film. 4. A liquid crystal display panel having liquid crystal sealed between two transparent substrates, and a flexible wiring board connected to the liquid crystal display panel, wherein the flexible wiring board comprises: A liquid crystal display device, comprising the flexible wiring board according to claim 1. 5. An electronic apparatus comprising the liquid crystal display device according to claim 4.