JP2987295B2 - Method and apparatus for bonding liquid crystal panels - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for bonding a liquid crystal panel in which two glass substrates are bonded with a photocurable adhesive in a process of assembling the liquid crystal panel.

[0002]

2. Description of the Related Art A liquid crystal screen comprises a liquid crystal panel, a driver for controlling the liquid crystal panel, and a backlight for illuminating the liquid crystal panel from the back. The liquid crystal panel encloses liquid crystal and controls the voltage applied to the liquid crystal to transmit or block light from the backlight, thereby displaying a screen.

FIG. 5 is a view showing an example of the above-mentioned liquid crystal panel (color liquid crystal panel). In FIG. 5, reference numeral 101 denotes a color filter substrate, 102 denotes a TFT substrate, and 103 denotes a TFT substrate.
FT element (thin film transistor), 104 is a black matrix, 105 is a scatter spacer, 106 is an alignment film,
Reference numeral 07 denotes a sealant, and reference numeral 108 denotes a display ITO electrode. In the figure, the horizontal direction is shown on a smaller scale than the vertical direction for easy understanding.

Generally, a liquid crystal panel is, as shown in FIG.
It is composed of two glass substrates including a color filter substrate 101 and a TFT substrate, and one of them has a driving element for driving liquid crystal, for example, a TFT element 103 or a liquid crystal driving electrode formed of a transparent conductive film. Have been. On the other glass substrate, a light-shielding film 104 called a black matrix, and in the case of a color liquid crystal panel, a color filter and the like are formed.

The black matrix 104 is formed of, for example, a chromium vapor-deposited film, a black resin, or the like. Light from the backlight is emitted from portions other than the liquid crystal which are not related to image display, that is, liquid crystal driving elements and wiring portions. It acts as a blindfold so that it does not leak and disturb the image. In the manufacturing process of the liquid crystal panel, the above two glass substrates are separately manufactured and then bonded with an adhesive (sealant 107 in FIG. 5).
At this time, spherical fine particles called spacers (spacers 105 in FIG. 5) are sprayed between the two glass substrates to form a gap between the two glass substrates for injecting liquid crystal.

The above-mentioned adhesive also serves as a seal for preventing liquid crystal from leaking. That is, the adhesive is applied in a thin line shape so as to surround the screen display portion. The width of the line is 1 to
It is about 1.5 mm. FIG. 6 is a view showing a state in which an adhesive (sealant) is applied on a glass substrate. As shown in FIG.
Surface) products. Then, an adhesive is applied so as to surround each product, and after bonding to a part thereof, an injection port for injecting liquid crystal is provided. Adhesives are applied to the four corners of the glass substrate for temporary fixing.

When the two glass substrates are bonded to each other, the two glass substrates are aligned so that the black matrix 104 is correctly overlapped with the portion to be shielded from light. In this state, the adhesive for temporary fixing is cured, and the glass substrate is temporarily fixed. Further, the adhesive (sealant) is cured while applying pressure in a direction in which the two glass substrates approach each other so that the gap becomes uniform over the entire substrate. And after lamination,
The glass substrate is separated for each product, and liquid crystal is injected from the injection port and sealed.

[0008] Conventionally, in the step of bonding two glass substrates, bonding is performed using a thermosetting adhesive. However, in this method, it is necessary to perform the treatment at a high temperature in order to cure the adhesive, and the two glass substrates are displaced during bonding and curing due to the thermal expansion of the glass substrate, which causes a product defect. I was For this reason, recently, a bonding technique of using a light-curing adhesive to cure with light without applying heat has been developed and used.

[0009]

However, when the above-mentioned photo-curing type adhesive is used for bonding, there are the following problems. When irradiating a liquid crystal panel with light to cure the adhesive, it is required that parts other than the adhesive, such as the liquid crystal driving element, be irradiated with light as little as possible. This is because when the liquid crystal driving element or the like is irradiated with strong light that cures the adhesive, the characteristics thereof may change undesirably. Amorphous materials used for thin film transistors
The phenomenon that the electrical characteristics of a silicon (a-Si: H) thin film is deteriorated by light irradiation is a well-known example.

In order to prevent these phenomena, when irradiating the liquid crystal panel with light, the light is radiated from the surface on which the black matrix is formed to the surface on which the liquid crystal driving elements and the like are formed. That is, light is emitted from the side opposite to the backlight (front side). As a result, an effect is obtained that the black matrix serves as a light shield and prevents the liquid crystal drive element and the like from being irradiated with light.

However, in an actual liquid crystal panel, the black matrix is usually formed so as to slightly cover the adhesive, and the width of the black matrix is 1 / the width of the adhesive.
It reaches about 3 (about 0.3 to 0.5 mm). this is,
This is to prevent light leakage of the backlight from the edge portion of the liquid crystal panel, and cannot be avoided due to the structure of the liquid crystal panel.

FIG. 7 is an enlarged view of the portion A in FIG. 5 (shown enlarged in the horizontal direction from FIG. 5). As shown in FIG. 7, when ultraviolet rays UV are irradiated from above the liquid crystal panel, A shadow portion S of about 0.3 to 0.5 mm is formed. That is, when light is irradiated from the surface on which the black matrix is formed by the above-described method in order to cure the adhesive, there is a problem that the portion covered by the black matrix becomes a shadow and the adhesive in this portion cannot be cured. Was.

When the liquid crystal is injected in a state where the adhesive is not sufficiently cured, the uncured adhesive component dissolves into the liquid crystal, deteriorating the characteristics of the liquid crystal, and peeling due to a decrease in adhesive strength. It may cause product failure. SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and a first object of the present invention is to irradiate a shadow portion formed by a black matrix with light, and An object of the present invention is to provide a method and an apparatus for bonding a liquid crystal panel, which can surely cure a mold adhesive.

A second object of the present invention is to surely cure a light-curable adhesive even when an adhesive having a large light absorption coefficient is used or when the thickness of the adhesive is large. It is an object of the present invention to provide a method and an apparatus for bonding a liquid crystal panel which can be performed. A third object of the present invention is to provide a method and an apparatus for bonding a liquid crystal panel which can be applied to a large glass substrate on which a plurality of products are mounted.

[0015]

According to a first aspect of the present invention, there is provided a liquid crystal panel bonding method for bonding two glass substrates with a photocurable adhesive. Of the two glass substrates, a light irradiating unit arranged so that light travels from one glass substrate on which a black matrix is formed to the other glass substrate on which a liquid crystal driving element or a liquid crystal driving electrode is formed is formed. Provided,
The light from the light irradiating unit is applied to a work in which an adhesive is sandwiched between two glass substrates in advance in a direction in which the two glass substrates relatively approach each other. The work is diffused in the vicinity of the work to irradiate the work.

According to a second aspect of the present invention, in the first aspect of the present invention, the workpiece is heated during or after light irradiation. According to a third aspect of the present invention, there is provided a liquid crystal panel bonding apparatus comprising: a light irradiating unit for emitting light; a work in which an adhesive is sandwiched between two glass substrates; A processing chamber provided with an opening or a light transmitting window for irradiating light from the work onto the work, a stage arranged in the processing chamber for holding the work, and two glass substrates of the work relatively It comprises a pressure mechanism for applying pressure in the approaching direction, and a light diffusing member arranged near the work between the work and the light irradiating section.

According to a fourth aspect of the present invention, in the third aspect of the present invention, the light transmitting window is constituted by a light diffusing member. According to a fifth aspect of the present invention, in the fourth aspect of the present invention, there is provided a support for dividing the light transmitting portion of the light diffusing member into a plurality. According to a sixth aspect of the present invention, in the third, fourth or fifth aspect, the light diffusing member is formed of a glass plate having a surface with minute irregularities.

According to the seventh aspect of the present invention, there is provided the third or fourth aspect.
Alternatively, in the fifth aspect of the present invention, the light diffusion member is formed of a glass plate containing a large number of minute air bubbles therein. The invention of claim 8 of the present invention relates to claims 3, 4,
In the fifth, sixth or seventh aspect of the present invention, a work cooling mechanism and / or a heating mechanism are provided.

[0019]

[Action]

(1) In the first and third aspects of the present invention, since the light from the light irradiating part is diffused near the work and irradiated onto the work as described above, the shadow covered by the black matrix The light also reaches the portion, and the adhesive in this portion can be cured.

Further, since this portion can be sufficiently cured, the uncured adhesive component dissolves into the liquid crystal, deteriorating the characteristics of the liquid crystal, and peeling due to a decrease in the adhesive strength. Nothing to do. (2) In the above invention, the light is diffused from the light irradiating section and irradiated onto the work to cure the adhesive in the shadow area, but the adhesive has a large light absorption coefficient (low transmittance). In the case or when the thickness of the adhesive is large, the intensity of the light reaching the depth of the shadow is greatly attenuated.

This is because light is greatly absorbed by the adhesive. If the overall light intensity is increased to obtain sufficient light intensity in this area, the light intensity in the area not covered by the black matrix becomes excessive, causing deterioration of the adhesive due to light, which may cause product defects. It can be. Therefore, in the invention of claim 2 of the present invention, the work is heated during or after the light irradiation.

[0022] For this reason, the insufficiently cured portion can be cured by heat with heat, and even when the adhesive has a large light absorption coefficient (low transmittance) or a large thickness as described above. Can be completely cured. In addition, since it is not necessary to increase the entire light intensity, the light intensity in a portion not covered by the black matrix does not become excessive and the adhesive does not deteriorate due to light. (3) In the above invention, when the light transmitting window and the light diffusing member are separately configured, the light passes through the two objects before reaching the work. When light passes through an object, the light attenuates due to loss due to surface reflection of the object. In the case of transparent glass, when light passes through a piece of glass, about 10 percent is lost due to surface reflection.

Therefore, when light passes through two objects, about 2
There is a problem that the light around 0% is attenuated, and the processing time becomes longer. Therefore, in the invention of claim 4 of the present invention, the light transmission window is formed of a light diffusion member. Therefore, the number of times that light passes through the object before reaching the workpiece is only one, and the loss due to surface reflection can be reduced, and the processing time can be shortened. (4) In recent liquid crystal manufacturing, a plurality of products have been manufactured from one large glass substrate for efficiency. When a pressure is applied to a work, the pressure needs to be 0.3 to 1 kgf per 1 cm ^2. For example, in the case of a glass substrate of 50 cm × 60 cm, the total pressure reaches 900 to 3000 kgf.

When the light diffusing member is arranged near the work as in the above invention, a large pressure is applied to the light diffusing member. The light diffusing member is usually made of a glass plate. However, if the light diffusing member is formed of a single glass plate, the thickness of the glass plate that can withstand the high pressure becomes thick, and it becomes very expensive and heavy. Therefore, in the invention of claim 5 of the present invention, a support for dividing the light transmitting portion of the light diffusing member into a plurality is provided.

Therefore, the pressure applied to the light diffusing member can be dispersed and supported, or the light diffusing member can be divided into a plurality of parts to reduce the pressure applied to one light diffusing member, and the glass plate can be made thin. Can be. Therefore, the price is low and the weight is light. In particular, even if the light diffusion portion is divided into a plurality of sections, the boundary between the sections is adjusted to the gap between a plurality of products on the substrate shown in FIG. 6 (a cutting allowance used for dividing and cutting out the products). It is possible to eliminate the adverse effects caused by the formation of a portion not exposed to light. (5) In the invention of claim 6 of the present invention, since the light diffusing member is formed of a glass plate having fine irregularities on the surface, the light diffusing member can be manufactured at a low cost by using ground glass that can be easily manufactured. Can be (6) As described above, if the ground glass is used, the light diffusion member can be made inexpensive. However, the ground glass has a problem that dirt attached to the surface is difficult to remove.

Therefore, in the invention of claim 7 of the present invention, the light diffusing member is formed of a glass plate containing a large number of minute bubbles inside. Since the surface of the glass plate containing a large number of minute bubbles is smooth, the dirt attached to the surface of the light diffusion member is formed by forming the light diffusing member with a glass plate containing a large number of minute bubbles therein. Can be easily dropped. (7) As described above, by heating the work during or after light irradiation, the insufficiently hardened portion can be auxiliary-hardened by heat.

Therefore, in the invention of claim 8 of the present invention, a work cooling mechanism and / or a heating mechanism are provided. Then, by heating the work by the heating mechanism, the insufficiently cured portion can be cured auxiliary. Further, by providing the cooling mechanism, it is possible to prevent an undesired temperature rise of the work due to heat from the lamp.

[0028]

FIG. 1 is a diagram showing a first embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a lamp that emits ultraviolet light, 2 denotes a mirror, 3 denotes a light transmitting window member and a light diffusing member that also serves as a light diffusing member, and FIG.
As shown in FIG. 2, the surface is made of ground glass having minute irregularities, or as shown in FIG. 3B, glass containing minute bubbles.

Reference numeral 4 denotes a work integrally formed by sandwiching an adhesive between the two glass substrates.
Are radiated by the mirror 2, are diffused by the light transmitting window member and light diffusing member 3, and enter the work 4 on the substrate side provided with the black matrix. 5 is a processing chamber, 6 is a stage on which a work is placed, and 7 is a guide member for guiding the stage 6 in the vertical direction. The stage 6 can be moved up and down by a stage elevating mechanism (not shown). As the stage elevating mechanism, a well-known moving mechanism combining a hydraulic cylinder, a motor, a ball screw, and the like can be used.

Reference numeral 10 denotes a heater, and reference numeral 11 denotes a water-cooled tube. The work can be heated by the heater 10. In order to prevent the work from being undesirably heated by the irradiated light, the work is cooled by the water-cooled tube 11. Can be cooled. Reference numeral 12 denotes a through hole provided in the stage 6, which introduces air from an air introduction port 13 and supplies air to the lower surface of the work 4 through the through hole 12, thereby forming the work 4.
Up and pressurized.

In this embodiment, the step of bonding the liquid crystal panels is performed as follows. (1) The work 4 is placed on the stage 6 in the processing chamber 5.
As described above, the work 4 is formed integrally by sandwiching an adhesive between two glass substrates, and is placed on the stage 6 such that the substrate side on which the black matrix is provided faces upward. Is done. (2) The stage 6 is raised by a stage elevating mechanism (not shown) to bring the work 4 sufficiently close to the light transmitting window member / light diffusing member 3, and then the position of the stage 6 is maintained. This holding can be realized by a well-known method such as providing an electromagnetic brake mechanism or the like in the stage elevating mechanism, or simply abutting the stage 6 against a stopper block or the like. (3) Air is introduced from the air inlet 13 of the stage 6,
Air is supplied to the lower surface of the work 4 through the through hole 12.
The work 4 rises by air pressure, and the upper surface comes into contact with the light transmitting window member / light diffusion member 3 and is pressed by air pressure. (4) The lamp 1 is irradiated with ultraviolet rays. Ultraviolet rays are diffused by the light transmitting window member and light diffusing member 3 and enter the work 4. Since the light is diffused by the light transmitting window member and the light diffusing member 3 and enters the work 4, the adhesive is uniformly irradiated.

If necessary, the stage 6 is heated by the heater 10 during the light irradiation or after curing to some extent by the light irradiation. Accordingly, even when the light absorption coefficient of the adhesive is large, or when the thickness of the adhesive is large, the adhesive can be sufficiently cured. By the way, in the conventional method that does not use the light diffusion member, first, the portion not covered by the black matrix is cured with light, and then the shadow portion covered by the black matrix is cured by heat. Since it is not cured at all, it requires a high temperature and a long time (200 ° C., 2 hours) similar to the curing method using only heat.

On the other hand, as described above, while curing with light,
Alternatively, if curing is carried out by heat after curing to some extent by light, the treatment is completed at a low temperature in a short time (120 ° C., 30 minutes). Further, since the temperature is low, there is no problem that the two glass substrates during bonding and curing are shifted due to thermal expansion. In the case where the work is undesirably heated by the irradiation of ultraviolet rays, cooling may be performed by flowing cooling water through the water cooling pipe 11. (5) After irradiating and heating the ultraviolet rays for a time necessary for the adhesive to cure, stop the irradiation and heating of the ultraviolet rays, stop the air supply, lower the stage 6, and lower the bonded work. Remove 4.

As described above, in the present embodiment, since the diffused light is incident on the work, the work can be irradiated with the ultraviolet light without unevenness. Since the ultraviolet rays can be irradiated, the adhesive can be sufficiently cured. In addition, since a heating mechanism is provided, even when the light absorption alone is insufficient, such as when the light absorption coefficient of the adhesive is large, or when the thickness of the adhesive is large, the combined use of heating can be used. The adhesive can be sufficiently cured.

Further, since the cooling mechanism is provided, the work is not heated to an undesired temperature by the light. In the above embodiment, the work is pressurized by air pressure. However, as the means for pressurizing the work, various other known means can be used. For example, the stage is moved to the work side by a hydraulic mechanism or the like. Then, the work can be pressurized.

FIG. 3 is a view showing a second embodiment of the present invention. This embodiment shows an embodiment of an apparatus suitable for applying to a bonding step of a large glass substrate on which a plurality of products are mounted. (A) shows the configuration of the present embodiment, and (b) shows the configuration when the present embodiment is not applied. 1A and 1B, the same components as those shown in FIG. 1 are denoted by the same reference numerals, 3 is a light transmitting window member / light diffusing member, 4 is a work, 6 is a stage, 22 Is a support for supporting the light transmitting window member and the light diffusing member 3.

As described above, in recent liquid crystal manufacturing, a plurality of products are manufactured from a single large glass substrate in order to improve efficiency. Hang on. For this reason, in the case where the glass substrate is large, in order to withstand the above large pressure, FIG.
As shown in (b), the thickness of the light transmitting window member / light diffusing member 3 becomes thick, and there is a problem that the light transmitting window member and the light diffusing member 3 become expensive and heavy.

Therefore, in the present embodiment, attention is paid to the fact that there is a gap (shaving margin) between a plurality of products on the glass substrate as shown in FIG. A support 22 is provided in the gap, and the light transmission window member and the light diffusion member 3 are supported by the support 22. Thereby, the thickness of the light transmitting window member / light diffusing member 3 can be reduced as shown in FIG.
The device can be inexpensive and its weight can be reduced.

Although the support 22 is provided at one position in the drawing, a plurality of supports may be provided as needed. FIG. 4 is a diagram showing a modification of the above embodiment, and the same components as those shown in FIG. 3 are denoted by the same reference numerals. In this embodiment, the light transmitting window member / light diffusing member 3 is divided at the support 22. According to this embodiment, the thickness of the light transmitting window member / light diffusing member 3 is the same as in the above embodiment. The thickness of the device can be reduced, the device can be inexpensive and its weight can be reduced, and the device can be made more inexpensive because a large light diffusing member is not required.

[0040]

As described above, the following effects can be obtained in the present invention. (1) Light from the light irradiating part is diffused in the vicinity of the work to irradiate the work, so that the light reaches the shadow part covered by the black matrix and the adhesive in this part can be cured. .

Further, since this part can be sufficiently cured, the uncured adhesive component does not dissolve into the liquid crystal and does not deteriorate the characteristics of the liquid crystal. Also, there is no occurrence of peeling due to a decrease in adhesive strength. (2) By heating the work during or after light irradiation, the insufficiently hardened part can be cured with heat, and the adhesive has a large light absorption coefficient or is thick In some cases, it can be completely cured. Also,
Since it is not necessary to increase the entire light intensity, the light intensity in a portion not covered by the black matrix does not become excessive and the adhesive does not deteriorate due to light. (3) By configuring the light transmission window with a light diffusing member, the number of times that light passes through the object before reaching the work can be reduced to one, and the loss due to surface reflection can be reduced. Can be shortened. (4) Since a support is provided to divide the light transmitting portion of the light diffusion member into a plurality of parts, the pressure applied to the light diffusion member can be dispersed and supported, or the light diffusion member can be divided into multiple parts to make one light diffusion The pressure applied to the member can be reduced, and the glass plate can be thinned. Therefore, the price is low and the weight is light. In particular, even if the light diffusing portion is divided into a plurality of sections, by adjusting the boundary between the sections to the gap between a plurality of products on the substrate, it is possible to eliminate the adverse effect caused by the formation of a section not exposed to light. (5) Since the light diffusing member is formed of a glass plate having fine irregularities on its surface, the light diffusing member can be made inexpensive using easily ground glass. (6) By forming the light diffusing member from a glass plate containing a large number of minute air bubbles therein, dirt attached to the surface of the light diffusing member can be easily removed. (7) By providing the work heating mechanism, the work can be heated by the heating mechanism, and the insufficiently hardened portion can be auxiliary-cured. Further, by providing the cooling mechanism, it is possible to prevent an undesired temperature rise of the work due to heat from the lamp.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of a light diffusing member according to the embodiment of the present invention.

FIG. 3 is a diagram showing a second embodiment of the present invention.

FIG. 4 is a diagram showing a modification of the second embodiment.

FIG. 5 is a diagram illustrating an example of a configuration of a liquid crystal panel.

FIG. 6 is a view showing a state in which an adhesive is applied on a glass substrate.

FIG. 7 is a partially enlarged view of FIG. 5;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Lamp 2 Mirror 3 Light transmission window member and light diffusion member 4 Work 5 Processing chamber 6 Stage 7 Guide member 10 Heater 11 Water cooling tube 12 Through hole 13 Air inlet 22 Support

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G02F 1/1339 505 G02F 1/13 101

Claims (8)

(57) [Claims] 1. A liquid crystal panel bonding method for bonding two glass substrates with a photo-curable adhesive, comprising the steps of: starting from one of the two glass substrates on which a black matrix is formed; Alternatively, a work is provided in which a light irradiator is provided so that light travels in the direction of the other glass substrate on which the liquid crystal drive electrode is formed, and an adhesive is sandwiched between two glass substrates in advance to form an integrated shape. On the other hand, in a state where pressure is applied in a direction in which the two glass substrates relatively approach each other, light from the light irradiation unit is diffused in the vicinity of the work to irradiate the work with light. Lamination method. 2. The method according to claim 1, wherein the work is heated during or after light irradiation. 3. A light irradiating unit for emitting light, a work integrally formed by sandwiching an adhesive between two glass substrates, and an opening for irradiating the work with light from the light irradiating unit. A processing chamber having a light transmitting window, a stage arranged in the processing chamber to hold the work, a pressurizing mechanism for applying pressure in a direction in which the two glass substrates of the work approach relatively, A device for bonding a liquid crystal panel, comprising: a light diffusing member disposed in the vicinity of a work between the work and a light irradiation unit. 4. The liquid crystal panel bonding apparatus according to claim 3, wherein the light transmitting window is a light diffusing member. 5. The liquid crystal panel bonding apparatus according to claim 4, further comprising a support for dividing the light transmitting portion of the light diffusing member into a plurality of parts. 6. The liquid crystal panel bonding apparatus according to claim 3, wherein the light diffusing member is a glass plate having a surface with minute irregularities. 7. The liquid crystal panel bonding apparatus according to claim 3, wherein the light diffusing member is a glass plate containing a large number of minute air bubbles therein. 8. A work cooling mechanism and / or a heating mechanism are provided.
8. A device for bonding a liquid crystal panel according to claim 7.