Patent Application
20080115883
1. Field of the Invention
The present invention generally relates to manufacturing methods and manufacturing apparatuses of panels, such as a liquid crystal display panel, which are formed by laminating a pair of substrate with each other. The present invention particularly relates to a manufacturing method and a manufacturing apparatus of a liquid crystal display panel, which is formed by injecting a liquid crystal into a cell space formed between a pair of transparent substrate. Hereinafter, a description will be given of a liquid crystal display panel as an example.
2. Description of the Related Art
In recent years, display devices represented by a liquid crystal display device, which performs screen display using a liquid crystal material, have been widely used as a display part of electronic equipments. A liquid crystal display device generally has a liquid crystal display panel, which is formed by injecting a liquid crystal into a cell space formed between a pair of transparent substrates so as to perform display by driving the liquid crystal by applying a drive voltage to electrodes of the liquid crystal display panel.
The transparent substrates of a liquid crystal display panel are, for example, glass substrates. A cell space into which a liquid crystal is injected is formed by laminating the glass substrates with each other by sandwiching a seal adhesive between the glass substrates. When laminating the glass substrates, it is necessary to apply a pressure onto the glass substrates so as to bring the seal adhesive into closely contact with the glass substrates. According to a conventional manufacturing method of a liquid crystal display panel, generally, the glass substrates are laminated by physically applying a press force onto the glass substrates
According to the method of physically applying a press force onto the glass substrates, it is difficult to apply a pressure uniformly onto the whole glass substrates. Thus, there is a problem in that a gap between the glass substrates to form the cell space becomes uneven. Additionally, in a case where a foreign matter is trapped between the glass substrates, a large press force is applied locally onto the glass substrates, which may generate a problem that the glass substrates are broken.
Instead of the glass substrates which are easily broken, transparent plastic substrates are used in some cases. However, when pressing a pair of plastic substrates from both sides, if there is a foreign matter between the plastic substrates, the plastic substrates may not be broken but deformed due to the foreign matter, which results in a problem in that the gap forming the cell space becomes uneven.
On the other hand, when laminating substrates with each other, if a surface area of each of the glass or plastic substrates is large, unevenness in the pressure being applied to the substrates tends to occur. Additionally, the pressing apparatus becomes large so that a large press force can be generated.
Conventionally, liquid crystal display panels are manufactured by laminating a pair of substrates, which forms a single liquid crystal display panel, one set by one set. However, the lamination process of the substrates requires a curing time for curing the seal material between the substrates. Thus, it takes a long time to manufacture many liquid crystal display panels, which results in a problem that a manufacturing cost of the liquid crystal display device is raised.
As a technique to reduce the manufacturing cost of the liquid crystal display device, there is suggested a method in which an opening is provided in the assembly of the laminated substrates and gas in the cell space is evacuated through the opening and thereafter a liquid crystal is injected through the same opening (for example, refer to Patent Document 1). In this method, a manifold for vacuum suction is pressed against the opening part of the substrate assembly so as to form a vacuum in the cell space through the manifold and the opening part.
Moreover, as a technique to apply a pressure onto the substrates with a simple mechanism, there is suggested a method in which a pair of substrates are sandwiched from both sides by magnetic sheets so as to press the substrates by a magnetic force (for example, refer to Patent Document 2).
Further, there is suggested a method of laminating large substrates and injecting a liquid crystal within a vacuum container (for example, refer to Patent Document 3). In this method, a magnetic fluid seal is used in a part where a vacuum pump is connected to the vacuum container.
Patent Document 1: Japanese Laid-Open Patent Application No. 2000-155325
Patent Document 2: Japanese Laid-Open Patent Application No. 2001-33791
Patent Document 3: Japanese Laid-Open Patent Application No. 2002-318378
In the conventional manufacturing method for manufacturing liquid crystal display panels, attention has been paid mainly to uniformization of pressure by manufacturing liquid crystal display panels one by one. Thus, it takes a time to manufacture many liquid crystal panels, and, as a result, there is a problem that the manufacturing cost of the liquid crystal display device goes up.
Moreover, there is a problem in that the pressure applied to the substrates, when laminating the substrates with each other, becomes uneven.
It is a general object of the present invention to provide an improved and useful manufacturing method and manufacturing apparatus of a panel, in which the above-mentioned problems are eliminated.
A more specific object of the present invention is to provide a manufacturing method and a manufacturing apparatus, which enables excellent lamination by pressurizing a pair of substrates with uniform pressure.
Another object of the present invention is to provide a manufacturing method and a manufacturing apparatus, which enables lamination of a plurality of sets of substrates at the same time.
In order to achieve the above-mentioned objects, there is provided according to one aspect of the present invention a manufacturing method of a panel that is formed by laminating a pair of substrates with each other, the manufacturing method comprising: a seal forming step of providing a first seal material on one of the substrates and providing a second seal material to completely surround the first seal material; a laminating step of laminating the pair of substrates with each other in a state where a cell space is formed between the substrates with the first and second seal materials sandwiched between the substrates; a depressurizing step of depressurizing an inner space of the second seal material containing the cell space through an opening provided outside the first seal material and inside the second seal material; and a removing step of removing a portion where the second seal material is provided so that the cell space formed by the first seal material remains.
In the manufacturing method according to the present invention, the seal forming step may include applying the first and second seal materials by a dispenser. The seal forming step may include providing the first seal material so as to form an opening connected to the cell space formed by the first seal material. An ultraviolet-light curable resin may be used as the first and second seal materials, and the seal forming step may include irradiating an ultraviolet light onto the first and second seal materials so as to set the first and second seal materials in a half-cured state. The laminating step may include irradiating an ultraviolet light onto the first and second seal materials so as to cure the first and second seal materials and tentatively fix the substrates to each other. The depressurizing step may include heating laminated the pair of substrates so as to cure the first and second seal materials. The depressurizing step may include supporting the pair of substrates by sandwiching a peripheral portion of an opening provided in the pair of substrates by a pair of magnets via elastic materials, and simultaneously connecting a suction pipe for depressurization to the opening via the elastic materials. The depressurizing step may be carried out in a state where a plurality of the pairs of substrates are accommodated in a heating oven. The seal forming step may include providing the first seal material so as to form a plurality of the cell spaces inside the second seal material.
The manufacturing method according to the present invention may further comprise a partition-wall forming step of forming partition walls in an area forming the cell space by the first seal material, the partition walls for dividing the cell space into small areas.
Additionally, there is provided according to another aspect of the present invention a manufacturing apparatus of a panel that is formed by laminating a pair of substrates with each other, the manufacturing apparatus comprising: a support mechanism that supports a substrate lamination assembly formed by laminating the pair of substrates and tentatively fixing to each other; and a depressurizing mechanism that depressurizes a cell space formed in the substrate lamination assembly through an opening formed in the pair of substrates of the substrate lamination assembly, wherein the support mechanism simultaneously performs the support of the substrate lamination assembly and the connection for depressurization of a space between the substrates by sandwiching a peripheral portion of the opening of the pair of substrates by a pair of elastic materials.
In the manufacturing apparatus according to the present invention, the support mechanism may include the pair of elastic materials and a magnet attached to each of the elastic materials, and the substrate lamination assembly may be supported by being sandwiched by the elastic materials by an attraction force between the magnets. The pair of elastic materials may include a first elastic material having a through hole and a second elastic material having no through hole, and wherein the connection for depressurization may be performed by positioning and fixing the substrate lamination assembly to the support mechanism so that the through hole of the first elastic material aligns with the opening of the substrate lamination assembly, and sealing the opening on a side opposite to a side facing the first elastic material by the second seal material. The support mechanism may further include a third elastic material having a through hole and a magnet attached to the third elastic material, and the support mechanism may support a plurality of the substrate lamination assemblies via the first and second elastic materials and the third elastic materials in a state where the plurality of substrate lamination assemblies can be depressurized.
The manufacturing apparatus according to the present invention may further comprise a heating oven that accommodates the support mechanism. The manufacturing apparatus may further comprise a suction apparatus located outside the heating oven so as to depressurize the substrate lamination assembly accommodated in the heating oven by using the suction apparatus as a suction source.
Additionally, there is provided according to another aspect of the present invention a manufacturing method of a panel that is formed by laminating a pair of substrates with each other, the manufacturing method comprising: a step of providing a seal part on at least one of the pair of substrates, the seal part to be provided between the pair of substrates; a step of facing the pair of substrates so as to sandwich the seal part therebetween; and a step of depressurizing a space between faced the substrates so as to laminate the pair of substrates with each other.
In the manufacturing method according to the present invention, the seal part may be provided on at least one of the pair of substrates so that the seal part surrounds a predetermined area with an opening formed by the seal part, the opening being formed by not providing a part of the seal part.
In the manufacturing method according to the present invention, a material may be used as the seal part, the material having an adhesion action to laminate the pair of substrates with each other. The manufacturing method according to the present invention may further comprise a step of forming a second seal part that surrounds the seal part outside an area where the seal part is formed, and wherein the depressurizing step may include depressurizing inside an area surrounded by the second seal part.
The manufacturing method according to the present invention may further comprise a step of forming a first opening and a second opening in an area inside the second seal part, the first opening formed in one of the pair of substrates and the second opening formed in the other of the pair of substrates at a position opposite to the first opening.
The manufacturing method according to the present invention may further comprise a connecting step of connecting, prior to the depressurizing step, a depressurizing mechanism performing depressurization to the first opening, and also connecting one of a seal material for sealing the second opening and a first opening formed in another pair of substrates to the second opening. In the manufacturing method according to the present invention, the connecting step may include connecting a plurality of the pair of substrates to the depressurizing mechanism, and the depressurizing step may include depressurizing spaces each of which is formed between respective one of the plurality of the pairs of substrates connected to the depressurizing mechanism simultaneously.
According to the present invention, the cell space is depressurized by evacuating gas from the cell space through the opening of the substrate lamination assembly having therein the cell space formed by laminating the substrates with each other, thereby allowing uniform pressurization of the substrates.
Other objects features and advantages of the present invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings.
A description will be given, with reference to the drawings, of lamination of substrates that constitute a liquid crystal display panel according to a first embodiment of the present invention. The liquid crystal display panel according to the present embodiment is formed by laminating two sheets of transparent substrate and injecting a liquid crystal into a space formed between the substrates.
First, a description will be given, with reference to
In the process shown in
First, a preparation process of the substrate 1a will be explained. As shown in FIG. 1-(a), transparent electrodes 2 are formed on the surface of the substrate 1a. The transparent electrodes 2 can be formed by a transparent and electrically conductive material. In FIG. 1-(a), the transparent electrodes 2 are indicated by dotted lines extending in a longitudinal direction in the figure for the sake of convenience. The transparent electrodes 2 are formed on the substrate 1a using photolithography. First, a resist made of an electrically conductive material is printed on the substrate la, and the transparent electrodes 2 of a linear form are formed by being subjected to exposure, development, etching and exfoliation processes. Thereafter, the substrate la is subjected to rinse and dry process, and, then, transferred to a partition-wall forming process.
In the partition-wall forming process, as shown in FIG. 1-(b), partition walls 3 are formed on the surface of the substrate 1a. Each of the partition walls 3 is a pillar-shaped member so that a portion surrounded by the partition walls 3 is defined as a single cell. The cell corresponds to a single pixel of the liquid crystal display device. In the partition-wall forming process, a resist made of a UV-curable resin is printed on the surface of the substrate 1a. The resist is subjected to a pre-baking process, and then subjected to exposure and development processes, which results in formation of the partition walls 3 in the resist. Then, portions of the resist other than the portions changed to the partition walls 3 are removed, and after being subjected to rinse and dry processes, only the partition walls 3 remain on the surface of the substrate 1a. Thereafter, the partition walls 3 are UV-cured, and bubbles in the partition walls 3 are removed by being subjected to a vacuum heating degassing process.
Next, in a seal forming process shown in FIG. 1-(c), a seal material 4 is applied by a dispenser so as to surround an area where the partition walls 3 are formed. The seal material 4 is a material that seals to form a cell space between the substrates 1a and 1b when laminating the substrate 1a and the substrate 1b mentioned later. In the present embodiment, the seal material 4 has a bonding function to bond the substrates 1a and 1b to each other as well as a sealing function. In the example of FIG. 1-(c), the partition walls 3 and the seal material are formed on the same surface of the substrate la. The applied seal material 4 is pre-baked by irradiation of UV (ultraviolet light). In this state, the partition walls 3 and the seal material 4 are in a half-cured state, and have adhesion. It should be noted that the method of providing the seal material is not limited to the application by the dispenser, and, for example, an adhesive seal material sheet previously formed in a predetermined shape may be applied to the substrate 1a. It should be noted that, as shown in FIG. 1-(c), there is an area where the seal material 4 is not applied. This area serves as a liquid crystal injection opening 4a (shown in FIG. 1-(h)) for injecting a liquid crystal between the laminated substrates.
Although FIG. 1-(a) to FIG. 1-(c) show a process of preparing the substrate 1a, the substrate 1b is prepared concurrently. The preparation of the substrate 1b is performed in a process shown in FIG. 1-(d) to FIG. 1-(f). First, as shown in FIG. 1-(d), transparent electrodes 5 are formed on the surface of the substrate 1b. The transparent electrodes 5 are formed by a process similar to the process of forming the transparent electrodes 2. The transparent electrodes 5 are formed to extend in a direction perpendicular to the extending direction of the transparent electrodes 2. It should be noted that when the substrates 1a and 1b are laminated, the transparent electrodes 2 and the transparent electrodes 5 are arranged to be perpendicular to each other so as to serve as electrodes that apply a drive voltage to the liquid crystal filled in the cell space.
Next, as shown in FIG. 1-(e), an insulating film 6 is formed so as to cover the transparent electrodes 5. The insulating film 6 is formed by printing and applying a liquid insulating material onto the entire surface of the substrate 1b where the transparent electrodes 5 are formed, and pre-baking the insulating material. It should be noted that the insulating film 6 is also transparent, but is indicated by cross-hatching in FIG. 1-(e) for the sake of convenience.
Next, as shown in FIG. I-(f), the spacers 7 are scattered on the pre-baked insulating film 6. The spacers 7 are extremely small transparent particles that are interposed between the substrates 1a and 1b when the substrates 1a and 1b are laminated so as to form a gap forming the cell space. Accordingly, the partition walls 3 formed on the substrate 1a and the spacers 7 provided on the substrate 1b cause the substrate la and the substrate 1b to face each other with a predetermined distance therebetween.
After completion of the preparation of the substrates 1a and 1b as mentioned above, the process proceeds to a laminating process. In the laminating process, as shown in FIG. 1-(g), the surface of the substrate 1a on which the partition walls 3 are formed and the seal material 4 is applied and the surface of the substrate 1b on which the spacers 7 are scattered are positioned to face each other, and the seal material 4 and the partition walls 3 are cured by UV irradiation while pressing at low pressing force so as to tentatively fix the substrate 1a and the substrate 1b to each other.
Next, in the process shown in FIG. 1-(h), the seal material 4 and the partition walls 3 are baked and cured by heating, for example, at 180° C. for 90 minutes while forming a vacuum in the cell space formed by being surrounded by the seal material 4. By evacuating gas through the liquid crystal injecting opening 4a, which is a part not provided with the seal material 4, an atmospheric pressure is applied to the substrates 1a and 1b from outside, and, thereby, the substrates 1a and 1b are in a pressurized state by an atmospheric pressure. Since the pressure applied to the substrates 1a and 1b is generated by an atmospheric pressure, the substrates 1a and 1b are subjected to uniform pressure. Thereby, the substrate la and the substrate 1b are laminated with each other in a state where they are apart from each other by the spacers 7 by a predetermined distance (for example, 0.015 mm), and the cell space surrounded by the seal material 4 is formed between the substrates 1a and 1b. It should be noted that if the seal material 4 and the partition walls 3 are made of a thermosetting resin, the seal material 4 and the partition walls 3 are heated to bake as mentioned above. However, if, for example, the seal material 4 and the partition walls 3 are made of a room temperature setting resin or a UV curable resin, there is no need to heat the laminated substrates while evacuating gas from the cell space. The seal material 4 and partition walls 3 may be cured by a curing process suitable for the material of the seal material 4 and partition walls 3.
Then, after the liquid crystal is injected into the cell space from the liquid crystal injecting opening 4a in the liquid crystal injecting process shown in FIG. 1-(i), the cell space is completely sealed and the liquid crystal display panel is completed.
The substrate lamination assembly 10 shown in
Although a vacuum suction apparatus for forming a vacuum in the cell space is connected to the liquid crystal injecting opening 4a in the process shown in FIG. 1-(h), in the substrate lamination assembly 10 shown in
A description will now be given, with reference to
An attachment block 21 is attached to an end of the suction pipe 20 of the vacuum suction apparatus (for example, a vacuum pump) not shown in the figure. A connection rubber, which is a first elastic material, is incorporated into the attachment block 21.
The substrate lamination assembly 10 is arranged so as to align, for example, the opening 12 of the substrate la with a through hole of the connection rubber, and a seal rubber 24, which is a second elastic material, is arranged so as to close the opening 12 of the substrate 1b. An annular magnet 25 similar to a magnet 23 attached to the connection rubber 22 is incorporated in the seal rubber 24 so that the magnet 23 and the magnet 25 face and attract each other when the seal rubber 24 is arranged to close the opening 12 of the substrate 1b. According to the attraction force of the magnet 23 and the magnet 25, the substrate lamination assembly 10 is fixed to the attachment block 21 and supported thereon. In this state, the connection rubber 22 contacts and seals the periphery of the opening 12 of the substrate la, and the seal rubber 24 contacts and seals the periphery of the opening of the substrate 12b. Thus, airtightness near the opening 12 is acquired by the connection rubber 22 and the seal rubber 24, which allows more efficient evacuation of gas inside the substrate lamination assembly 10.
It should be noted that the connection rubber 22 and the seal rubber 24 are not limited to rubber if an elastic material having a seal function is used. The connection rubber 22 and the seal rubber 24 may be replaced with seal material formed of flexible plastics. However, in a case where the seal material is of a thermosetting type, it is preferable to use a material having heat resistance such as silicon or fluorocarbon since the baking process is performed in the state shown in
As mentioned above, if the substrate lamination assembly 10 shown in
It should be noted that since the substrate lamination assembly 10 shown in
A description will now be given, with reference to
In order to attach a plurality of the substrate lamination assemblies 10 to the same suction pipe 20, first, as shown in
Then, the opening 12 of a second sheet of the substrate lamination assemblies 10 is fit to the positioning pin 30, and, subsequently, a relay rubber 31b is fit to the positioning pin 30. Thereby, the magnet 32a incorporated in the relay rubber 31a and a magnet 32b incorporated in the relay rubber 31b attract each other, and, thus, the second sheet of the substrate lamination assemblies 10 is supported on the attachment block 21 via the first sheet of the substrate lamination assemblies 10 (the relay rubber 31a—the connection rubber 23). In this manner, a desired number of the substrate lamination assemblies 10 are fit to the positioning pin 30, and, thereafter, the positioning pin 30 is removed. At this time, the substrate lamination assemblies 10 other than the last sheet of the substrate lamination assemblies 10 are supported by the magnets arranged between the substrate lamination assemblies 10. Here, the last sheet of the substrate lamination assemblies 10 means the substrate lamination assemblies 10 fit to the positioning pin 30 for the last time. Thus, only the last sheet of the substrate lamination assemblies 10 has to be supported.
Then, while supporting the last sheet of the substrate lamination assemblies 10, the seal rubber 24 is attached to the opening 12 of the last sheet of the substrate lamination assemblies 10 as shown in
As mentioned above, by using the substrate lamination assembly 10 shown in
After the process of evacuating gas is ended, the substrate lamination assemblies 10 can be removed easily by stopping the evacuation and merely removing the seal rubber 24 and the relay rubber 31 by hand.
Moreover, the portions of the substrate lamination assemblies 10 sandwiched by the connection rubber 21, the relay rubbers 31 and the seal rubber 24 are outside portions of the portions where the cell spaces are formed, and a force of the magnets to sandwich the substrate lamination assemblies 10 is not applied to the portion of the substrates where the cell spaces are formed, and, thus, a local force is not applied to the portion where the cell space is formed, which enables formation of the cell space having uniform gap.
Further, since the substrate laminating process is performed in a state where the opening is provided at one position of the substrate lamination assembly and the substrate lamination assembly is suspended due to a gravity by supporting the opening part, an external force other than an atmospheric pressure due to the evacuation is not applied to the substrate lamination assembly, which results in formation of the cell space having uniform gap.
Here, a plurality of cell spaces can be formed in a single sheet of the substrate lamination assembly by applying the structure of the substrate lamination assembly 10 shown in
In the substrate lamination assembly 40 shown in
The substrate lamination assembly 40 is connectable to the vacuum suction apparatus according to a method shown in
Thus, if a plurality of cell spaces are formed in a single sheet of the substrate lamination assembly, gas can be evacuated simultaneously from a plurality of cell spaces corresponding to a plurality of liquid crystal display panels by merely connecting the single sheet of the substrate lamination assembly to the vacuum suction apparatus. Accordingly, the curing process of the seal material forming a plurality of cell spaces can be performed at the same time, which results in a reduction in the manufacturing cost per one liquid crystal display panel. Additionally, by connecting a plurality of substrate lamination assemblies each of which having a plurality of cell spaces formed therein according to the method shown in
A description will now be given, with reference to
The baking apparatus as a manufacturing apparatus of the liquid crystal display panel shown in
In the oven 50, a support mechanism is provided so as to support the substrate lamination assembly 60. The support mechanism includes the attachment block 21, the connection rubber 22, the relay rubbers 31a and 31b, the seal rubber 24, and the magnets 23, 32a, 32b and 25 attached to the rubbers shown in
A plurality of the substrate lamination assemblies 60 can be accommodated in the oven 50 in a state where they are supported on the attachment block 21. Here, the substrate lamination assembly 60 has the same structure as the substrate lamination assembly 40 shown in
In the example shown in
A plurality of substrate lamination assemblies 60 in which the substrates are tentatively fixed to each other in the process shown in FIG. 1-(g) is attached to the attachment block 21 in the oven 50, and, thereafter, the vacuum suction apparatus 51 is operated so as to evacuate gas from the substrate lamination assemblies 60 and a temperature inside the oven 50 is raised to a curing temperature (for example, 180° C.) of the seal material 4 and the temperature is maintained for a predetermined time (for example, 90 minutes). Thereby, the seal material 4 is completely cured, which results in completion of the liquid crystal display panel.
After the seal material 4 is completely cured, the substrate lamination assemblies 60 are taken out of the oven 50, and each substrate lamination assembly 60 is cut and divided into individual cell spaces. Thereafter, a liquid crystal is injected into each cell space, and the liquid crystal display panels are completed.
As mentioned above, according to the baking apparatus shown in
The present invention is not limited to the specifically disclosed embodiments, and variations and modifications may be made without departing from the scope of the present invention.
Present invention is based on Japanese priority application No. 2006-313404 filed Nov. 20, 2006, the entire contents of which are hereby incorporated herein by reference.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2006-313404 | Nov 2006 | JP | national |
