JPH11288002A - Liquid crystal driving circuit module and liquid crystal display device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the structure of a liquid crystal display device for improving the electric/mechanical reliability of a flexible connection circuit connecting a liquid crystal substrate and a liquid crystal driving module. SOLUTION: When a liquid crystal driving circuit module is bent to the loading face side of liquid crystal driving LSI 4 in a connection circuit which connects a liquid crystal substrate 2 and the liquid crystal driving circuit module, which is printed into multiple layers in a flexible insulating film and which can he bent, the conductor layer 6 of the connection circuit is arranged so that it is shifted in the direction of the surface of the insulating film from the center of the thickness of the insulating film 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a liquid crystal display substrate,
The present invention relates to a liquid crystal drive circuit module and a liquid crystal display device using the same.

[0002]

2. Description of the Related Art A liquid crystal display device generally has a structure including a liquid crystal panel in which a liquid crystal material is sandwiched between two opposing substrates, and a drive circuit module for driving the liquid crystal panel.

FIG. 8 is an explanatory sectional view showing a peripheral portion of a conventional liquid product display device, and FIG. 8B is an enlarged explanatory view of a portion E in FIG. In the figure, 101 is a display element, 102
Is a liquid crystal substrate, 103 is a color filter substrate, 104 is a driving LSI, 105 is a flexible insulating film, 106 is a conductor layer which is a driving circuit pattern, 107 is a lighting device provided on the back surface of the liquid crystal substrate 102, and 108 is a module A substrate,
112 is a drive LSI connection terminal, 113 is a liquid crystal drive module connection terminal, and 114 is liquid crystal.

Here, the liquid crystal material is held between the liquid crystal substrate 102 and the color filter substrate 103 to form a liquid crystal panel.

As a method of manufacturing a module substrate, first, a substrate made of soda glass, borosilicate glass, alumina, or the like having a thickness of 0.5 mm to 1.1 mm is placed on a substrate.
A photosensitive or non-photosensitive polyimide resin is applied and cured to form a base insulating layer. Subsequently, a conductor layer (copper) is formed on the base insulating layer by a sputtering method or an electroless plating method, and then a polyimide resin is formed to form a surface insulating layer. Thereafter, a notch for bending is made on the back surface of the module substrate with a diamond wheel to break the substrate. At this time, since the flexible insulating film has toughness and remains without being broken, the drive circuit module shown in FIG. 8 is formed.

Further, the driving module substrate is connected to the liquid crystal substrate mounting portion by soldering, and the driving LSI 104 is mounted at a predetermined position to manufacture a liquid crystal display device.

[0007]

As described above,
In the conventional liquid crystal display device, since the area of the drive circuit needs to be smaller than the area of the display portion of the liquid crystal panel, the flexible conductive film is bent to arrange the module substrate on which the drive circuit is mounted on the side surface or the back surface. It is essential. In this flexible conductive film, the position of the conductive layer is usually at the center of the entire thickness. However, when an excessive load is applied at the time of bending, there is a problem that a portion of the conductor layer may be damaged or the gland may be cut off.

In the case of forming a flexible connection circuit manufactured by forming a cutout on the back surface of a liquid crystal substrate and breaking the cutout, in the conventional structure, the strength of the circuit conductor in the flexible conductive film portion is reduced. There is a problem that it may not be possible to sufficiently maintain

The present invention solves the above-mentioned problems,
Reduce the damage of the conductor layer when bending the flexible conductor film,
In addition, a drive circuit module and a drive circuit module in which a flexible conductive film portion is not easily broken when forming a flexible connection circuit manufactured by providing a cutout on the back surface of a liquid crystal substrate and breaking the cutout are provided. It is an object to provide a liquid crystal display device using the same.

[0010]

According to the liquid crystal driving circuit module of the present invention, a flexible insulating film is formed on a substrate made of a hard base material having no flexibility. A liquid crystal drive circuit module having a conductive layer multi-layer printed in a conductive insulating film and a liquid crystal drive LSI mounted thereon, wherein the liquid crystal drive circuit module is
When the conductor layer is bent toward the mounting surface side of the SI, the conductor layer is arranged so as to be shifted from the center of the thickness of the insulating layer toward the surface of the insulating film.

In a liquid crystal driving circuit module according to a second aspect of the present invention, the liquid crystal driving LSI is formed on the same liquid crystal substrate on which a liquid crystal display element is provided, and a cutout is provided on the back surface of the liquid crystal substrate to be cut. A liquid crystal drive circuit module having a foldable connection circuit formed by multi-layer printing of a conductive layer in a flexible insulating film, wherein the liquid crystal drive LSI is mounted Is bent in the front direction of the liquid crystal substrate, and the conductor layer is disposed so as to be shifted from the center of the thickness of the insulating layer toward the surface of the insulating film.

In a liquid crystal drive circuit module according to a third aspect of the present invention, the insulating film is made of any one of photosensitive polyimide, non-photosensitive polyimide, photosensitive epoxy, and non-photosensitive epoxy.

In a liquid crystal drive circuit module according to a fourth aspect of the present invention, when the thickness of the insulating film is 29 μm and the thickness of the conductive layer is 5 μm, the position of the conductive layer is the thickness of the insulating film. 6.5 to 7.5 μ from center to insulating film surface direction
It is arranged so as to be shifted by m.

In a liquid crystal driving module according to a fifth aspect of the present invention, the liquid crystal driving LSI is formed on the same liquid crystal substrate on which the liquid crystal display element is provided, and the liquid crystal substrate is cut off by providing a cutout on the back surface thereof. Formed by, and
What is claimed is: 1. A liquid crystal driving circuit module having a foldable connection circuit in which a conductive layer is printed in multiple layers in a flexible insulating film, wherein the liquid crystal substrate on which the liquid crystal driving LSI is mounted is directed in the front direction of the liquid crystal substrate. When the conductive layer is folded, the conductive layer is disposed so as to be shifted from the center of the thickness of the insulating layer toward the surface of the insulating film, and further, an adhesive resin is applied to the folded cross section of the liquid crystal substrate. It has been done.

In a liquid crystal driving circuit module according to a sixth aspect of the present invention, a liquid crystal driving LSI is formed on the same liquid crystal substrate on which a liquid crystal display element is provided, and a cutout is provided on the back surface of the liquid crystal substrate to be cut. A liquid crystal driving circuit module having a foldable connection circuit formed by multi-layer printing of a conductor layer in a flexible insulating film, wherein the liquid crystal substrate portion on which the liquid crystal driving LSI is mounted is provided. When bent 180 degrees in the front direction of the liquid crystal substrate, the position of the conductor layer is arranged so as to be shifted from the center of the thickness of the insulating layer toward the surface of the insulating film. An adhesive resin is injected into the bent portion and fixed.

A liquid crystal display according to a seventh aspect of the present invention comprises at least a liquid crystal drive circuit module according to the first aspect and a liquid crystal display panel.

A liquid crystal display according to an eighth aspect of the present invention comprises at least the liquid crystal drive circuit module according to the second, third or fourth aspect and a liquid crystal display panel.

A liquid crystal display according to a ninth aspect of the present invention comprises at least the liquid crystal drive circuit module according to the fifth aspect and a liquid crystal display panel.

A liquid crystal display according to a tenth aspect of the present invention comprises at least the liquid crystal drive circuit module according to the sixth aspect and a liquid crystal display panel.

According to the first aspect of the present invention, in the connection circuit multilayer printed on the flexible insulating film, the conductor layer of the connection circuit is arranged to be shifted from the center of the thickness of the insulating film in the surface direction. I have. For this reason, as shown in FIG. 5, the distribution of the bending stress in the cross section of the connecting circuit is such that the tensile stress generated in the conductor layer is smaller and the compressive stress is higher than when the conductor is arranged at the center of the thickness.

FIG. 5, FIG. 6 and FIG. 7 are explanatory diagrams showing the distribution of bending stress in the cross section of the connection circuit. In FIG. 6, 61 is an insulating film, 62 is a conductor wiring portion, 63 is a portion where a conductor peels off, 64 is a portion where the conductor peels off, D ₁ and D ₂ show bending directions,
h ₁ and h ₂ represents the stress, S ₁ to S ₆ shows the stress curve, respectively.

In addition, as shown in FIG. 2, when the liquid crystal and the driving circuit are mounted on the same substrate, and a cutout is formed on the back surface of the liquid crystal substrate and the liquid crystal substrate is cut to form a flexible connection circuit. Also, the conductor layer can be arranged so as to be shifted from the center of the thickness of the insulating layer in the surface direction. In this case, in addition to the above-described effect of the stress distribution, the thickness of the insulating layer below the conductor layer increases, so that the toughness of the flexible connection circuit when the substrate is broken increases.

In addition, a connection circuit having higher reliability can be obtained by preventing the conductor layer from reaching the surface of the insulating film at least at the bent portion. The reason for this is that, as shown in FIG. 6A, when the conductor layer reaches the surface, the conductor layer peels due to buckling when the connection circuit is bent, making it difficult to maintain the compressive stress. It is because it becomes.
If the conductor layer has not reached the surface, as shown in FIG. 6B, the insulation layer is arranged so as to surround the connection circuit, so that the conductor layer does not peel. Functionally satisfactory even if the conductor layer peels off,
For products with low reliability requirements, the insulating film on the surface of the conductor layer is unnecessary. However, when reliability is required, it is essential that the conductor layer be in the insulating film.

[0024]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

Embodiment 1 FIG. 1 is an explanatory sectional view showing the structure of a liquid crystal display according to an embodiment of the present invention.

In the figure, 1 is a display element, 2 is a liquid crystal substrate, 3 is a color filter substrate, 4 is a driving LSI, 5 is a flexible insulating film, 6 is a conductor layer which is a connection circuit pattern wiring,
7 is a lighting device provided on the back surface of the liquid crystal substrate 2, 8 is a liquid crystal driving circuit module substrate on which a driving LSI is mounted,
Reference numeral 12 denotes a drive LSI connection terminal, 13 denotes a liquid crystal drive module connection terminal, and 14 denotes a liquid crystal.
FIG. 2 is an enlarged explanatory view of a portion A in FIG.

In this embodiment, in a bendable liquid crystal drive circuit module on which a liquid crystal drive LSI is mounted, when the liquid crystal drive circuit module is bent 90 degrees toward the mounting surface of the liquid crystal drive LSI, the position of the conductive layer is changed. It is arranged so as to be shifted from the center of the thickness of the insulating layer toward the surface of the flexible insulating film. In the present embodiment, the other points that the liquid crystal drive circuit module substrate is configured as described above are the same as the conventional liquid crystal display device, and the liquid crystal substrate includes a liquid crystal substrate, a color filter substrate, and a liquid crystal sandwiched by both substrates. A liquid crystal display panel according to the present invention can be obtained by combining the liquid crystal liquid crystal display panel with the liquid crystal driving circuit module according to the present invention and adding a lighting device and the like.

Embodiment 2 FIG. 1 has described a structure in which a liquid crystal substrate and a liquid crystal drive circuit module are connected by a connection circuit. FIG. 2 is a cross-sectional explanatory view showing an example in which a liquid crystal and a driving circuit are mounted on the same substrate (liquid crystal substrate). In FIG.
The same elements as those shown in FIG. 1 are denoted by the same reference numerals (the same applies to FIG. 3 and subsequent figures). (B) of the figure is an enlarged explanatory view of a portion B in (a). In this structure, as shown in FIG. 2, a notch is provided on the back surface of the liquid crystal substrate and the liquid crystal substrate is cut to form a flexible connection circuit, and the drive circuit is bent 90 degrees in the front direction. At this time, the conductor layer is arranged so as to be shifted from the center of the thickness of the insulating layer in the surface direction.

In this case, for forming the flexible insulating film, for example, a photosensitive polyimide, a non-photosensitive polyimide, a photosensitive epoxy, or a non-photosensitive epoxy having good adhesion to a liquid crystal substrate (eg, glass) is used. Can be. When the material is changed, the adhesion between the flexible insulating film and the conductor layer (for example, copper) is relatively inferior to that of the flexible insulating film and the substrate (for example, glass). Due to various factors, it is necessary to change the position where the conductor layer is shifted from the center of the thickness of the insulating layer in the surface direction each time. In one example of the present embodiment, the total thickness of the flexible insulating film (polyimide) is 29 μm.
When the thickness of the conductor layer (copper) is 5 μm, the optimum value of the amount of shift is set to 6.5 to 7.5 μm. Here, the reason why the optimum value of the shift amount is set to 6.5 μm or more is to reduce the tensile stress on the liquid crystal surface side. This is for maintaining the toughness of the insulating layer. Even when the thickness of the flexible insulating film and the thickness of the conductor layer are different, the optimum value of the amount to be shifted in consideration of the above-mentioned adhesive strength factor and the tensile stress on the liquid crystal surface side and the toughness of the lower insulating layer. Can be determined.

Third Embodiment FIG. 3 is a cross-sectional view showing an example in which, after the drive circuit module is bent in the same structure as in FIG. 2, an adhesive resin 9 is applied to the folded cross section of the liquid crystal substrate and fixed. FIG.
(B) of the figure is an enlarged explanatory view of the portion C in (a). Here, a room temperature curing type resin can be used as the bonding resin 9, and specific examples include a silicone resin.

Fourth Embodiment FIG. 4 shows a structure in which a liquid crystal and a driving circuit are mounted on the same substrate, and a cutout is provided on the back surface of the liquid crystal substrate to be cut to form a flexible connection circuit. 2 is an explanatory cross-sectional view showing an example of a structure in which a driving circuit is bent 180 degrees in the front direction, and FIG. 2B is an enlarged explanatory view of a portion D in FIG. In this case, the conductor layer is arranged so as to be shifted in the surface direction from the center of the thickness of the insulating film. In this structure, after the drive circuit is bent, the bonding resin 9 may be injected into the bent portion of the liquid crystal substrate and fixed. Here, a room temperature curing type resin can be used as the bonding resin 9, and specific examples include a silicone resin.

[0032]

According to the first aspect of the present invention, when the drive circuit module is bent 90 degrees in the back direction of the liquid crystal substrate, the conductor layer of the flexible connection circuit is turned from the center of the thickness of the insulating layer to the surface. Because it is shifted in the opposite direction to
Due to the effect shown in FIG. 6, the tensile stress on the liquid crystal surface side of the conductor layer is reduced. For this reason, the destruction of the conductor layer can be prevented, and the electrical and mechanical reliability of the liquid crystal substrate increases. Although the compressive stress of the conductor layer increases, the compressive stress does not contribute to the destruction, so that the effect of improving the strength occurs as described above.

According to the second aspect of the present invention, the substrate of the drive circuit portion cut off from the liquid crystal substrate is moved 90 degrees in the front direction.
Since the conductor layer of the flexible connection circuit is displaced from the center of the thickness of the insulating film in the surface direction during the bending, the tensile stress on the liquid crystal surface side of the conductor layer is reduced by the effect shown in FIG. Become smaller. For this reason, the destruction of the conductor layer can be prevented, and the electrical and mechanical reliability of the liquid crystal substrate increases. Although the compressive stress of the conductor layer increases, the compressive stress does not contribute to the destruction, so that the effect of improving the strength occurs as described above.

In addition, since the conductor layer is displaced in the surface direction from the center of the thickness of the insulating layer when the liquid crystal substrate is broken, in addition to the effect of the stress distribution, the thickness of the insulating layer below the conductor layer is reduced. By increasing the toughness, the toughness of the flexible connection circuit when the substrate is broken is increased, and the insulating layer is less likely to be broken.

In this shape, for example, the drive circuit module was bent 180 times by 50 times. In the conventional structure, the conductor layer was broken, but in the present structure, the conductor layer was not broken. Although the number of times of destruction varied depending on the circuit pattern of the conductor layer, the strength of this structure was improved in any case.

According to the third aspect of the present invention, since the insulating film is made of any one of photosensitive polyimide, non-photosensitive polyimide, photosensitive epoxy and non-photosensitive epoxy, it has good adhesion to the liquid crystal substrate. This has the effect of reducing the tensile stress on the liquid crystal surface side of the conductive layer.

According to the fourth aspect of the invention, when the thickness of the insulating film is 29 μm and the thickness of the conductor layer is 5 μm, the position of the conductor layer is from the center of the thickness of the insulating film to the insulating film. Since it is arranged so as to be shifted by 6.5 to 7.5 μm in the surface direction, in addition to the effect of stress distribution, the thickness of the insulating layer below the conductor layer is increased, so that the flexible connection is achieved. This has the effect of increasing the toughness of the circuit for use when the substrate is broken, making it difficult for the insulating layer to break.

According to the fifth aspect of the invention, in addition to the effects described in the second aspect of the present invention, the liquid crystal substrate has a structure in which an adhesive resin is applied to and fixed to the folded section of the liquid crystal substrate. Thus, the substrate of the drive circuit portion that has been broken can be held, and the compressive stress generated in the cross section of the flexible connection circuit can be maintained. For this reason, the destruction of the conductor layer can be prevented, and the electrical and mechanical reliability of the liquid crystal substrate increases.

According to the sixth aspect of the present invention, the substrate of the drive circuit portion cut off from the liquid crystal substrate is moved 18
At the time of bending by 0 degree, the conductor layer of the flexible connection circuit is displaced from the center of the thickness of the insulating layer in the surface direction, and the resin for bonding is injected into the bent portion of the liquid crystal substrate and fixed. Therefore, in addition to the effect described in claim 2, the substrate of the drive circuit portion cut off from the liquid crystal substrate can be held, and the compressive stress generated in the cross section of the flexible connection circuit can be maintained. Further, in the present structure, the substrate of the drive circuit portion is folded, so that the frame area of the liquid crystal substrate can be extremely reduced.

According to the invention according to claim 7, since at least the liquid crystal drive circuit module according to claim 1 and the liquid crystal display panel are provided, the electric and mechanical reliability of the liquid crystal substrate is increased. A display device can be provided.

According to the eighth aspect of the present invention, since at least the liquid crystal drive circuit module and the liquid crystal display panel according to the second, third or fourth aspect are provided, the electrical and mechanical reliability of the liquid crystal substrate is improved. Can be provided.

According to the ninth aspect of the present invention, since at least the liquid crystal drive circuit module according to the fifth aspect and the liquid crystal display panel are provided, the liquid crystal substrate has increased electrical and mechanical reliability. A display device can be provided.

According to the tenth aspect, since at least the liquid crystal drive circuit module and the liquid crystal display panel according to the sixth aspect are provided, the electrical and mechanical reliability of the liquid crystal substrate is increased. Further, since the substrate of the drive circuit portion is folded, a liquid crystal display device in which the frame area of the liquid crystal substrate can be extremely reduced can be provided.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view of a liquid crystal display device according to a first embodiment of the present invention.

FIG. 2 is an explanatory sectional view of a liquid crystal display device according to Embodiment 2 of the present invention.

FIG. 3 is an explanatory sectional view of a liquid crystal display device according to Embodiment 3 of the present invention.

FIG. 4 is an explanatory sectional view of a liquid crystal display device according to a fourth embodiment of the present invention.

FIG. 5 is a conceptual explanatory diagram illustrating the operation of the present invention.

FIG. 6 is a conceptual explanatory view when a conductor layer having an insulating film reaches the surface of the insulating film.

FIG. 7 is a conceptual explanatory diagram when a conductor layer having an insulating film reaches the surface of the insulating film.

FIG. 8 is an explanatory sectional view showing a conventional liquid crystal display device.

[Description of Signs] 1 display element, 2 liquid crystal substrate, 3 color filter substrate, 4 driving LSI, 5 flexible insulating film, 6 conductor layer,
7 lighting device, 8 drive circuit module board, 9 resin for bonding.

Claims (10)

[Claims] 1. A flexible insulating film is formed on a substrate made of a rigid base material having no flexibility, a conductor layer is printed in a multilayer in the flexible insulating film, and a liquid crystal driving LSI is formed. A foldable liquid crystal driving circuit module mounted thereon, wherein when the liquid crystal driving circuit module is bent toward the mounting surface side of the liquid crystal driving LSI, the position of the conductive layer is from the center of the thickness of the insulating layer to the surface of the insulating film. A liquid crystal drive circuit module arranged to be shifted in the direction. 2. A liquid crystal driving LSI is formed on the same liquid crystal substrate on which a liquid crystal display element is provided, and is formed by forming a cutout on the back surface of the liquid crystal substrate and breaking the liquid crystal substrate. What is claimed is: 1. A liquid crystal driving circuit module having a foldable connection circuit in which a conductor layer is multilayer-printed in an insulating film, wherein a liquid crystal substrate portion on which the liquid crystal driving LSI is mounted is bent in the front direction of the liquid crystal substrate. A liquid crystal driving circuit module, wherein the position of the conductor layer is shifted from the center of the thickness of the insulating layer toward the surface of the insulating film. 3. The liquid crystal drive circuit module according to claim 2, wherein the insulating film is made of one of photosensitive polyimide, non-photosensitive polyimide, photosensitive epoxy, and non-photosensitive epoxy. 4. When the thickness of the insulating film is 29 μm and the thickness of the conductive layer is 5 μm, the position of the conductive layer is 6.5 to 7 from the center of the thickness of the insulating film toward the surface of the insulating film. .5μ
4. The liquid crystal drive circuit module according to claim 3, wherein the liquid crystal drive circuit module is arranged so as to be shifted by m. 5. A liquid crystal driving LSI is formed on the same liquid crystal substrate on which a liquid crystal display element is provided, and is formed by forming a cutout on the back surface of the liquid crystal substrate and breaking the same, and is flexible. What is claimed is: 1. A liquid crystal drive circuit module having a foldable connection circuit in which a conductor layer is multilayer-printed in an insulating film, wherein the liquid crystal substrate portion on which the liquid crystal drive LSI is mounted is bent toward the front of the liquid crystal substrate. ,
A liquid crystal drive circuit module, wherein the position of the conductor layer is displaced from the center of the thickness of the insulating layer toward the surface of the insulating film, and an adhesive resin is applied to a folded section of the liquid crystal substrate; . 6. A liquid crystal driving LSI is formed on the same liquid crystal substrate on which a liquid crystal display element is provided, a notch is provided on the back surface of the liquid crystal substrate, and the liquid crystal driving LSI is formed by cutting. What is claimed is: 1. A liquid crystal driving circuit module having a foldable connection circuit in which a conductor layer is printed in multiple layers in a film, wherein a liquid crystal substrate portion on which the liquid crystal driving LSI is mounted is bent 180 degrees in a front direction of the liquid crystal substrate. Meanwhile, the position of the conductor layer is arranged so as to be shifted from the center of the thickness of the insulating layer toward the surface of the insulating film, and an adhesive resin is injected into the bent portion of the liquid crystal substrate and fixed. Liquid crystal drive circuit module. 7. A liquid crystal display device comprising at least the liquid crystal drive circuit module according to claim 1 and a liquid crystal display panel. 8. A liquid crystal display device comprising at least the liquid crystal drive circuit module according to claim 2, and a liquid crystal display panel. 9. A liquid crystal display device comprising at least the liquid crystal drive circuit module according to claim 5 and a liquid crystal display panel. 10. A liquid crystal display device comprising at least the liquid crystal drive circuit module according to claim 6 and a liquid crystal display panel.